Title of Invention

POLYTRIMETHYLENE TEREPHTHALATE RESIN AND METHOD FOR PREPARING THE SAME."

Abstract A polytrimethylene terephthalate resin which comprises 90 to 100 mole % of a trimethylene terephthalate recurring unit and 0 to 10 mole % of at least one monomer unit derived from a monomer which is different from the monomer used for forming said recurring unit and is copolymerizable with at least one monomer used for forming VDLGUHFXUULQJXQLWDQGH[KLELWV $ DOLPLWLQJYLVFRVLW\ >@ RIWR4.0 dl/g, (B) a molecular weight distribution (Mw/Mn) of 2.0 to 2.7, (C) a brightness index L value (L-1) of 70 to 100 and a chromaticness index b* value (b*-1) of -5 to 25, and (D) , after the heat treatment at 180°C for 24 hours in an air atmosphere, a L value (L-2) of 70 to 100 and b* value (b*-2) of -5 to 25. (FIG. - 1)
Full Text TITLE OF THE INVENTION
Polytrimethylene terephthalate resin
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a polytrimethylene
terephthalate resin. More particularly, the present in-
vention is concerned with a polytrimethylene terephtha-
late resin comprised mainly of trimethylene terephthalate
recurring units, which has the following characteristics:
an intrinsic viscosity of from 0.8 to 4.0 dl/g; a molecu-
lar weight distribution (Mw/Mn) of from 2.0 to 2.7; a
psychometric lightness L-value (L-l) of from 70 to 100
and a psychometric chroma b*-value (b*-l) of from -5 to
25; and a psychometric lightness L-value (L-2) of from 70
to 100 and a psychometric chroma b*-value (b*-2) of from
-5 to 25 as measured after heating the polytrimethylene
terephthalate resin at 180 °C for 24 hours in air. By
using the polytrimethylene terephthalate resin of the
present invention, a shaped article having high strength
and excellent color can be stably produced on a commer-
cial scale. Further, the present invention is also con-
cerned with a method for stably producing the poly-
trimethylene terephthalate resin with high productivity
on a commercial scale.
Prior Art
A polytrimethylene terephthalate resin (hereinaf-
ter, referred to as "ptt") not only has characteristics
similar to those of a nylon (e.g., soft feeling due to
the low elasticity of the resin, excellent elastic re-
covery and good dyeability), but also has characteris-
tics similar to those of a polyethylene terephthalate
(hereinafter, referred to as "PET") (e.g., wash and
wear property, dimensional stability and discoloration
resistance). Therefore, a PTT has been attracting at-
tention as a raw material which can be used for produc-
ing carpets, clothes, shaped articles and the like.
For further expanding the application fields of a
PTT, it has been desired to improve the strength and
color of the fibers and shaped articles of a PTT.
For improving the strength of the fibers and
shaped articles of a polymer, it is necessary to in-
crease the polymerization degree of the polymer, and to
narrow the molecular weight distribution of the polymer
so as to reduce the amount of low molecular weight
components in the polymer. Further, for improving the
color of the fibers and shaped articles of a polymer,
it is necessary not only to improve the whiteness of
the polymer, but also to improve the heat resistance of
the polymer so as to prevent the discoloration of the
polymer, which is caused by the thermal history experi-
enced by the polymer during the drying, melting and the
like.
As a polymerization method for producing a PTT, a
melt polymerization method is widely known. For exam-
ple, Unexamined Japanese Patent Application Laid-Open
Specification No. Hei 5-262862 (corresponding to U.S.
Patent No. 5,340,909), WO98/23662, WO01/14450 and
WO01/14451 disclose a method in which a melt polymeri-
zation is performed using a polymerization vessel
equipped with a stirrer. The above-mentioned polymeri-
zation vessel has advantages in that it exhibits excel-
lent volume efficiency and has a simple structure.
Such a polymerization vessel can be used on a small
scale for efficiently performing a polymerization to
produce a polymer having a high polymerization degree.
However, when the above-mentioned polymerization vessel
is used for performing a polymerization on a commercial
scale, the depth of the liquid reaction mixture in the
polymerization vessel inevitably becomes deep, leading
to a marked occurrence of heat decomposition of the
polymer. Thus, a polymer having high polymerization
degree cannot be produced on a commercial scale.
Various techniques have been proposed for produc-
ing a PTT having a high polymerization degree by melt
polymerization. Examples of such techniques include a
technique in which a lower alcohol diester of
terephthalic acid and trimethylene glycol are subjected
to a transesterification reaction and a polycondensa-
tion reaction in the presence of a titanium compound,
wherein the molar ratio of the lower alcohol diester of
terephthalic acid to trimethylene glycol is in the
range of from 1/1.2 to 1/1.8 (Unexamined Japanese Pat-
ent Application Laid-Open Specification No. Sho 51-
140992); a technique in which an organometal catalyst
is used as a polycondensation catalyst, and an organic
sulfonic acid or an aliphatic carboxylic acid is used
as a catalyst auxiliary (U.S. Patent No. 4,611,049); a
technique in which a tin catalyst is used as a polycon-
densation catalyst (Unexamined Japanese Patent Applica-
tion Laid-Open Specification No. Hei 5-262862 (corre-
sponding to U.S. Patent No. 5,340,909)),- a technique in
which a specific titanium catalyst is used as a poly-
condensation catalyst (Unexamined Japanese Patent Ap-
plication Laid-Open Specification Nos. 2000-159875 and
2000-159876); a technique in which an antimony compound
is used as a polycondensation catalyst (Chemical Fiber
International Vol. 46, pp 263-264, 1996); a tech-
nique in which heat decomposition of a PTT is sup-
pressed by using a hindered phenol-type stabilizer hav-
ing a specific structure (Unexamined Japanese Patent
Application Laid-Open Specification No. Sho 51-142097);
and a technique in which the by-production of acrolein
(formed by heating of a prepolyiner and a polymer in air
during the polymerization) is suppressed by blocking
the terminals of the prepolymer and the polymer with a
phosphorus-containing stabilizer and a hindered phenol
-type stabilizer (WO98/23662 and WO99/11709). However,
the above-mentioned techniques are disadvantageous in
that the molecular weight of the obtained PPT is not
satisfactorily high, in that a lowering of the molecu-
lar weight of the PTT occurs during the molding thereof,
and/or in that a discoloration of the PTT occurs. Thus,
by the above-mentioned techniques, a PTT having satis-
factory properties cannot be obtained.
Further, a method is proposed in which, for the
purpose of obtaining a high molecular weight PTT which
exhibits excellent heat stability during the spinning
of the PTT, a solid-phase polymerization of a PTT pre-
polymer having a relatively low molecular weight is
performed, in which the PTT prepolymer has not suffered
heat decomposition and has excellent color (Unexamined
Japanese Patent Application Laid-Open Specification No.
Hei 8-311177, Japanese Patent Application prior-to-
examination Publication (Tokuhyo) No. 2000-502392 and
Korean Patent No. 1998-061618). However, the solid-
phase polymerization proceeds while releasing
trimethylene glycol (hereinafter, referred to as "TMG")
from the surface of pellets of the prepolymer during
the polymerization reaction. Therefore, the polymeri-
zation degree varies depending on the size and shape of
the pellets, and also varies depending on the position
in the pellets. Therefore, the PTT obtained by this
method is markedly non-uniform with respect to the po-
lymerization degree. Further, in the solid-phase po-
lymerization, the pellets of the solid prepolymer get
rubbed with one another over a long period of time,
thereby generating a polymer powder which becomes a
loss. Furthermore, in the above-mentioned method, the
solid-phase polymerization should be conducted after
the production of the prepolymer by the melt polymeri-
zation and the like, and thus, the entire process for
producing a PTT becomes complicated and costly. Still
further, the presence of the polymer powder in the
spinning process causes breakage or fuzzing of polymer
fibers. For removing the polymer powder, an addition
step therefor becomes necessary.
As a method for producing a PTT having a high po-
lymerization degree only by melt polymerization, a
technique has been proposed in which the polymerization
is performed using a disc ring reactor or a cage type
reactor (WO00/64962) or a disc and donut conductor (U.S.
Patent No. 5,599,900) to withdraw the TMG efficiently
from the reaction system. However, each of the above-
mentioned apparatuses is a horizontal agitation-type
polymerizer which is equipped with a rotary driving
part. Therefore, in the above-mentioned method, when a
polymerization is performed under a high vacuum for ob-
taining a polymer having a high polymerization degree,
it is impossible to seal the driving part completely.
Thus, it is impossible to prevent the intrusion of a
trace amount of oxygen into the polymer, and hence, a
discoloration of the polymer inevitably occurs. Espe-
cially, in the case of a PTT, such discoloration mark-
edly occurs. When the driving part is sealed with a
sealing liquid, it is likely that the sealing liquid
gets mixed with the polymer, thereby lowering the qual-
ity of the resultant PTT. Further, even when the driv-
ing part of the apparatus is tightly sealed at the
start of the operation thereof, the tightness of the
sealing is lowered during the operation conducted for a
long period of time. Thus, the above-mentioned method
also has a serious problem with respect to the mainte-
nance of the apparatuses.
On the other hand, a method for producing a resin
(other than PTT) is known in which the polymerization
apparatus used therein does not have a rotary driving
part, and a polymerization is performed by allowing a
prepolymer to fall from a perforated plate (free-fall
polymerization method).
For example, a method is disclosed in which a
polyester prepolymer is allowed to fall in the form of
fibers in vacuo in an attempt to obtain a polyester
having a desired molecular weight (U.S. Patent No.
3,110,547). In this method, a polymerization reaction
is performed in a one pass mode without recycling the
polymer, because the recycling of a polymer which has
already been allowed to fall in the form of fibers
causes the lowering of the quality of the final polyes-
ter. However, the above-mentioned method has the fol-
lowing disadvantages. The polymer in the form of fi-
bers are easily broken during the polymerization reac-
tion, thereby causing a disadvantageously large varia-
tion in quality of the final condensation polymer prod-
ucts. In addition, a low molecular weight condensation
polymer is scattered from the polymer fibers during the
polymerization reaction to stain the lower surface of
the perforated plate. Due to such staining of the
lower surface of the perforated plate, it becomes dif-
ficult to cause the polymer to fall in the form of fi-
bers, so that the polymer fibers contact with one an-
other to cause breakage of the polymer fibers or the
polymer fibers are combined together to form a thick
fiber in which the reaction does not proceed effi-
ciently.
In order to solve these problems, various methods
have been proposed. Examples of such methods include a
method in which a polyester or a polyamide is produced
by allowing a prepolymer to fall along and in contact
with the surface of a perforated guide or a wire guide,
which is vertically arranged in a reaction vessel, so
that the polymerization of the prepolymer is effected
during the fall thereof (Examined Japanese Patent Ap-
plication Publication No. Sho 48-8355 and Unexamined
Japanese Patent Application Laid-Open Specification No.
Sho 53-17569); a method for continuously condensation-
polymerizing bis-(ß-hydroxyalkyl) terephthalate (which
is an initial-stage condensation product of polyethyl-
ene terephthalate (PET)), in which bis-(ß-hydroxyalkyl)
terephthalate is allowed to fall along and in contact
with wire guides in an atmosphere of inert gas, wherein
the wire guides are hung vertically from the holes of a
perforated plate, so that the polymerization of bis-(ß-
hydroxyalkyl) terephthalate is effected during the fall
thereof (Examined Japanese Patent Application Publica-
tion No. Hei 4-58806); and a method for producing a
melt-polycondensation polymer, such as a polyester, a
polyamide and a polycarbonate, in which a melt
-polycondensation prepolymer is caused to absorb an in-
ert gas, and then, polymerized under reduced pressure
(WO99/65970 which also discloses an apparatus used in
the method).
However, each of the above patent documents only
describes a method for producing a polyester, such as a
PET, or nylon, and has no proposal or suggestion about
the production of a PTT. As a result of the studies of
the present inventors, it has been found that, when any
of the above-mentioned methods are simply applied to
the production of a PTT (that is, when the production
of a PTT is conducted by the above-mentioned methods,
using raw materials and conditions which are conven-
tionally used in the production of a PTT), a foaming of
a polymer vigorously occurs, thereby staining the lower
surface of the perforated plate or the inner wall of
the reaction vessel having the guides provided therein.
A PTT is susceptible to heat decomposition, as compared
to a PET. Therefore, the stain caused by the above
-mentioned vigorous foaming of the polymer is easily
decomposed. When the resultant decomposition products
get mixed with the polymer, disadvantages are caused in
that the quality of the polymer is lowered, in that the
desired polymerization degree cannot be obtained, and
in that the obtained PTT suffers discoloration. Fur-
ther, the simple application of the above-mentioned
methods to the production of PTT is accompanied by
problems in that it is difficult to achieve a satisfac-
torily high polymerization degree, and in that the fi-
nal PTT contains low molecular weight polymers, which
result in a broad molecular weight distribution of the
final polymer and are likely to lower the mechanical
strength of an ultimate shaped article.
As mentioned above, the conventional methods for
producing a PTT have the following problems:
(1) It is difficult to produce a PTT having a high
polymerization degree only by melt polymerization (i.e.,
without solid-phase polymerization) on a commercial
scale. When the production of a PTT is conducted by
solid-phase polymerization, disadvantages are caused in
that the molecular weight distribution of the obtained
PTT becomes too broad, and in that the production proc-
ess becomes complicated and costly (due to the loss
caused by the formation of polymer powder).
(2) When it is attempted to produce a PTT having high
polymerization degree by using a specific catalyst or
stabilizer, the obtained polymer is likely to suffer
heat decomposition and discoloration.
With respect to the free-fall method (in which a
polymerization is performed by allowing a prepolymer to
fall freely in the form of fibers from a perforated
plate) and the guide-wetting fall method (in which a
polymerization is performed by allowing a prepolymer to
fall along and in contact with a guide), it is known
that these methods can be used for producing polyamide
and polyesters (such as a PET) other than a PTT. How-
ever, the application of the above-mentioned methods to
the production of a PTT is not known, and a PTT having
satisfactory properties cannot be obtained by a simple
application of these methods to the production of a PTT
which is different from the above-mentioned polyamides
and other polyesters with respect to the melt viscosity,
and resistance to heat decomposition, and volatilities
of by-products.
For these reasons, there has been a demand for the
development of a method which can be used for producing
an excellent PTT having a high polymerization degree on
a commercial scale, which PTT can be used for stably
producing a shaped article having excellent strength
and color.
SUMMARY OF THE INVENTION
In this situation, the present inventors have made
extensive and intensive studies with a view toward
solving the above-mentioned problems accompanying the
prior art techniques. As a result, it has unexpectedly
been found that, by polymerizing a molten form of a
specific trimethylene terephthalate prepolymer by the
so-called "guide-wetting fall process" at a temperature
of from the crystalline melting point of the prepolymer
to 290 ° C, it becomes possible to produce a specific
excellent polytrimethylene terephthalate resin which
can be used for stably producing a shaped article
exhibiting excellent strength and color. The above-
mentioned specific polytrimethylene terephthalate resin
is composed mainly of recurring units of trimethylene
terephthalate, and has the following characteristics:
an intrinsic viscosity [n] of from 0.8 to 4.0 dl/g; a
molecular weight distribution (Mw/Mn) of from 2.0 to
2.7; a psychometric lightness L-value (L-1) of from 10
to 100 and a psychometric chroma b*-value (b*-l) of
from -5 to 25; and a psychometric lightness L-value (L-
2) of from 70 to 100 and a psychometric chroma b*-value
(b*-2) of from -5 to 25 as measured after heating the
polytrimethylene terephthalate resin at 180 ° C for 24
hours in air. The present invention has been completed,
based on these novel findings.
Accordingly, it is an object of the present inven-
tion to provide a polytrimethylene terephthalate resin
which can be used for stably producing a shaped article
having excellent strength and color on a commercial
scale.
The foregoing and other objects, features and ad-
vantages of the present invention will be apparent from
the following description and appended claims taken in
connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
Fig. 1 shows an explanatory diagrammatic view of
an example of a reaction vessel which can be used in
the present invention;
Fig. 2 shows explanatory diagrammatic views of ex-
amples of an inert gas absorption device and a reaction
vessel, which can be used in the present invention; and
Each of Figs. 3 to 6 is an explanatory diagram-
matic view of one form of a production system used for
practicing the method of the present invention.
Description of Reference Characters and Numerals
A: Polytrimethylene terephthalate prepolymer
B: Polytrimethylene terephthalate resin
C: Mixture of raw materials (including a starting
monomer, a reactant monomer, a catalyst, an additive
and the like)
D: Exhaust gas
E: Inert gas
1, 14, 18, 28, 32, N2 and N7: Transferring pump
2 : Inlet for prepolymer A
3 , N4 : Perforated plate
4 : Observing window
5, N5: Guide
5 " : Polymer falling along and in contact with
the guide
6 : Inlet for gas
7, 13, 17, 21, 24, 27 and 31: Vent
8 : Withdrawal pump for polymer 5"
9: Outlet for polymer 5"
10: Polymerizer
11: Esterification reaction vessel
12, 16, 20, 23, 26 and 30: Agitation element
15: First vertical agitation type polymerizer
19: Second vertical agitation type polymerizer
22: Horizontal agitation type polymerizer
25: First transesterification reaction vessel
29: Second transesterification reaction vessel
Nl: Inert gas absorption device
N3 : Inlet for raw materials
N6: Inlet for inert gas
DETAILED DESCRIPTION OF THE INVENTION
In one aspect of the present invention, there is
provided a polytrimethylene terephthalate resin com-
prising -.
90 to 100 mole % of trimethylene terephthalate re-
curring units, and
0 to 10 mole % of at least one monomer unit se-
lected from the group consisting of monomer units ob-
tained from comonomers which are other than the mono-
mers used for forming the trimethylene terephthalate
recurring units and which are copolymerizable with at
least one of the monomers used for forming the
trimethylene terephthalate recurring units,
the polytrimethylene terephthalate resin having
the following characteristics (A) to (D):
(A) an intrinsic viscosity [r|] of from 0.8 to 4.0
dl/g;
(B) a molecular weight distribution of from 2.0 to
2.7 in terms of the Mw/Mn ratio, wherein Mw represents
the weight average molecular weight of the poly-
trimethylene terephthalate resin and Mn represents the
number average molecular weight of the polytrimethylene
terephthalate resin;
(C) a psychometric lightness L-value (L-l) of from
70 to 100 and a psychometric chroma b*-value (b*-l) of
from -5 to 2 5; and
(D) a psychometric lightness L-value (L-2) of from
7 0 to 100 and a psychometric chroma b*-value (b*-2) of
from -5 to 25 as measured after heating the poly-
trimethylene terephthalate resin at 180 ° C for 24 hours
in air.
For easy understanding of the present invention,
the essential features and various preferred embodi-
ments of the present invention are enumerated below.
1. A polytrimethylene terephthalate resin comprising:
90 to 100 mole % of trimethylene terephthalate re-
curring units, and
0 to 10 mole % of at least one monomer unit se-
lected from the group consisting of monomer units ob-
tained from comonomers which are other than the mono-
mers used for forming the trimethylene terephthalate
recurring units and which are copolymerizable with at
least one of the monomers used for forming the
trimethylene terephthalate recurring units,
the polytrimethylene terephthalate resin having
the following characteristics (A) to (D):
(A) an intrinsic viscosity [r\] of from 0.8 to 4.0
dl/g;
(B) a molecular weight distribution of from 2.0 to
2.7 in terms of the Mw/Mn ratio, wherein Mw represents
the weight average molecular weight of the poly-
trimethylene terephthalate resin and Mn represents the
number average molecular weight of the polytrimethylene
terephthalate resin;
(C) a psychometric lightness L-value (L-l) of from
70 to 100 and a psychometric chroma b*-value (b*-l) of
from -5 to 2 5; and
(D) a psychometric lightness L-value (L-2) of from
70 to 100 and a psychometric chroma b*-value (b*-2) of
from -5 to 25 as measured after heating the
polytrimethylene terephthalate resin at 180 ° C for 24
hours in air.
2. The polytrimethylene terephthalate resin according
to item 1 above, wherein the polytrimethylene
terephthalate resin has an intrinsic viscosity [r\] of
from 1.25 to 2.5 dl/g.
3. The polytrimethylene terephthalate resin according
to item 1 or 2 above, which has a terminal carboxyl
group content of from 0 to 20 meq/kg.
4. The polytrimethylene terephthalate resin according
to any one of items 1 to 3 above, which has a molecular
weight distribution of from 2.0 to 2.6.
5. The polytrimethylene terephthalate resin of any
one of items 1 to 4 above, which is in the form of pel-
lets.
6. The polytrimethylene terephthalate resin according
to item 5 above, wherein the pellets have an average
weight of from 1 to 1000 mg per pellet, and wherein the
pellets contains a powder of the polytrimethylene
terephthalate resin in an amount of 0 to 0.5 % by
weight, based on the total weight of the pellets, which
powder passes through a 30-mesh filter and does not
pass through a 300-mesh filter.
7. The polytrimethylene terephthalate resin according
to item 5 or 6 above, wherein the pellets have a crys-
tallinity (Xc) of 40 % or less, wherein the crystallin-
ity is defined by the following formula:
Xc (%) = {?c X (?s - ?a)}/{?s X (?c - ?a)} X
100
wherein pa is 1.300 g/cm3 which is an amor-
phous density of trimethylene terephthalate
homopolymer, pc is 1.431 g/cm3 which is a
crystal density of trimethylene terephtha-
late homopolymer, and ps represents a den-
sity (g/cm3) of the pellets.
8. A method for producing a polytrimethylene
terephthalate resin, which comprises:
(1) providing a molten form of a trimethylene
terephthalate prepolymer comprising:
90 to 100 mole % of trimethylene terephthalate re-
curring units, and
0 to 10 mole % of at least one monomer unit se-
lected from the group consisting of monomer units ob-
tained from comonomers which are other than the mono-
mers used for forming the trimethylene terephthalate
recurring units and which are copolymerizable with at
least one of the monomers used for forming the
trimethylene terephthalate recurring units,
the trimethylene terephthalate prepolymer having
an intrinsic viscosity [n] of from 0.2 to 2 dl/g, and
(2) polymerizing the molten form of a trimethylene
terephthalate prepolymer at a temperature which is
equal to or higher than the crystalline melting point
of the prepolymer and is not higher than 290 °C under
reduced pressure by the guide-wetting fall process in
which the prepolymer is allowed to fall along and in
contact with the surface of a guide so that polymeriza-
tion of the prepolymer is effected during the fall
thereof.
9. The method according to item 8 above, wherein the
molten prepolymer is continuously fed to a polymeriza-
tion reaction zone for effecting the polymerization of
the prepolymer in the step (2) and the resultant poly-
trimethylene terephthalate resin produced in the step
(2) is continuously withdrawn from the polymerization
zone, so that the step (2) for prepolymer polymeriza-
tion is continuously performed.
10. The method according to item 8 or 9 above, wherein
the guide has at least one portion selected from the
group consisting of a concave portion, a convex portion
and a perforated portion.
11. The method according to any one of items 8 to 10
above, wherein the prepolymer falling along and in con-
tact with the surface of the guide is in a foaming
state.
12. The method according to any one of items 8 to 11
above, wherein the polymerization in the step (2) is
performed, while introducing inert gas to the polymeri-
zation reaction zone.
13. The method according to item 12 above, wherein the
amount of the inert gas introduced to the polymeriza-
tion reaction zone is in the range of from 0.05 to 100
mg per gram of the polytrimethylene terephthalate resin
withdrawn from the polymerization reaction zone.
14. The method according to item 12 or 13 above,
wherein at least a part of the inert gas is introduced
to the polymerization reaction zone, independently from
the feeding of the trimethylene terephthalate prepoly-
mer to the polymerization reaction zone.
15. The method according to any one of items 12 to 14
above, wherein at least a part of the inert gas is in-
troduced to the polymerization reaction zone in such a
form as absorbed or contained in the trimethylene
terephthalate prepolymer.
16. The method according to any one of items 8 to 15
above, wherein the prepolymer has an intrinsic viscos-
ity [t|] of from 0.5 to 2.0 dl/g and a terminal carboxyl
group ratio of 50 % or less in terms of the molar ratio
(%) of the terminal carboxyl groups of the prepolymer
to all terminal groups of the prepolymer.
17. The method according to any one of items 8 to 16
above, wherein the prepolymer is produced by at least
one polymerization method selected from the following
methods (a) to (d):
(a) a polymerization method using a vertical agi-
tation type polymerizer;
(b) a polymerization method using a horizontal
agitation type polymerizer;
(c) a polymerization method using a free-fall po-
lymerizer having a perforated plate; and
(d) a polymerization method using a thin film type
polymerizer.
18. The method according to item 17 above, wherein the
prepolymer is produced by the method (b).
19. A polytrimethylene terephthalate resin produced by
the method of any one of items 8 to 18 above.
Hereinbelow, the present invention is described in
detail.
The polytrimethylene terephthalate resin of the
present invention comprises:
90 to 100 mole % of trimethylene terephthalate re-
curring units, and
0 to 10 mole % of at least one monomer unit se-
lected from the group consisting of monomer units ob-
tained from comonomers which are other than the mono-
mers used for forming the trimethylene terephthalate
recurring units and which are copolymerizable with at
least one of the monomers used for forming the
trimethylene terephthalate recurring units.
The trimethylene terephthalate recurring units are
formed by reacting a terephthalic acid material with a
trimethylene glycol material. Examples of terephthalic
acid materials include terephthalic acid, and diesters
of terephthalic acid, such as dimethyl terephthalate.
Examples of trimethylene glycol materials include 1,3-
propanediol, 1,2-propanediol, 1,1-propanediol, 2,2-
propanediol, and a mixture thereof. From the viewpoint
of stability, 1,3-propanediol is especially preferred,
as a trimethylene glycol material.
Examples of the above-mentioned comonomers include
ester-forming monomers, such as 5-sulfoisophthalic acid
sodium salt, 5-sulfoisophthalic acid potassium salt, 4-
sulfo-2,6-naphthalenedicarboxylic acid sodium salt,
3,5-dicarboxylic acid benzenesulfonic acid tetramethyl-
phosphonium salt, 3,5-dicarboxylic acid benzenesulfonic
acid tetrabutylphosphonium salt, 3,5-dicarboxylic acid
benzenesulfonic acid tributylmethylphosphonium salt,
3,6-dicarboxylic acid naphthalene-4-sulfonic acid
tetrabutylphosphonium salt, 3,6-dicarboxylic acid naph-
thalene-4-sufonic acid tetramethylphosphonium salt,
3,5-dicarboxylic acid benzenesulfonic acid ammonium
salt, 3,2-butanediol, 1,3-butanediol, 1,4-butanediol,
neopentyl glycol, 1,5-pentamethyleneglycol, 1,6-
hxamethylene glycol, heptamethylene glycol, octamethyl-
ene glycol, decamethylene glycol, dodecamethylene gly-
col, 1,4-cyclohexanediol, 1,3-cyclohexanediol, 1,2-
cyclohexanediol, 1,4-cyclohexanedimethanol, 1,3-
cyclohexanedimethanol, 1,2-cyclohexanedimethanol, ox-
alic acid, malonic acid, succinic acid, gultaric acid,
adipic acid, heptanedioic acid, octanedioic acid, seba-
cic acid, dodecanedioic acid, 2-methylgultaric acid, 2-
methyladipic acid, fumaric acid, maleic acid, itaconic
acid, 1,4-cyclohexanedicarboxylic acid, 1,3-
cyclohexanedicarboxylic acid and 1,2-
cyclohexanedicarboxylic acid.
The polytrimethylene terephthalate resin of the
present invention may further comprise: cyclic or chain
oligomers other than polytrimethylene terephthalate
resin; monomers, such as dimethyl terephthalate (here-
inafter, referred to as "DMT"), terephthalic acid
(hereinafter, referred to as "TPA") and trimethylene
glycol (hereinafter, referred to as "TMG"); and/or any
of various additives, such as a delustering agent, a
thermal stabilizer and a flame retardant.
For obtaining a fiber or a shaped article, which
has excellent strength and color, and which is aimed at
in the present invention, it is necessary not only to
improve the polymerization degree of the polytrimethyl-
ene terephthalate resin while narrowing the distribu-
tion of polymerization degree, but also to improve the
whiteness of the resin while improving the resistance
of the resin against the discoloration at high tempera-
tures .
As a yardstick of the polymerization degree, the
intrinsic viscosity [r|] can be used. For obtaining the
above-mentioned excellent fiber or shaped article,
which has excellent strength, it is necessary that the
resin (used for producing the fiber or shaped article)
have an intrinsic viscosity of 0.8 dl/g or more. On
the other hand, from the viewpoint of improving the
moldability of the resin and the ease in measuring the
amount of the resin in a gear pump, the intrinsic vis-
cosity should not be too high. For this reason, it is
necessary that the intrinsic viscosity [n] be 4.0 dl/g
or less. The intrinsic viscosity [n] is preferably in
the range of from 1.05 to 3.0 dl/g, more preferably
from 1.25 to 2.5 dl/g, still more preferably from 1.3
to 2.0 dl/g.
Further, for improving the strength of the above-
mentioned fiber or shaped article, not only should the
average polymerization degree be high, but also the
amount of a low molecular weight polymer should be low,
namely, the molecular weight distribution should be
narrow. In the present invention, the molecular weight
distribution is expressed in terms of a value (Mw/Mn)
which is calculated by dividing the weight average mo-
lecular weight (Mw) by the number average molecular
weight (Mn), wherein each of Mw and Mn is measured by
gel permeation chromatography. In the present inven-
tion, it is necessary that the Mw/Mn value be 2.7 or
less. The Mw/Mn value is preferably 2.6 or less, more
preferably 2.5 or less, still more preferably 2.4 or
less. In general, the lower limit of the molecular
weight distribution of a condensation polymer is 2.
With respect to the color of the polytrimethylene
terephthalate resin, for suppressing the darkening of the
ultimate shaped article and for enabling the resin to ex-
hibit a desired color by the use of a dye or a pigment,
it is necessary that the polytrimethylene terephthalate
resin have a psychometric lightness L-value (L-l) of 70
or more and a psychometric chroma b*-value (b*-l) of -5
or more. From the viewpoint of suppressing the discol-
oration of the resin by heat decomposition, it is neces-
sary that the polytrimethylene terephthalate resin have a
psychometric chroma b*-value of 25 or less. There is no
particular limitation with respect to the upper limita-
tion of the (L-l) value, but in general, it is 100. The
(L-l) value is preferably 75 or more, more preferably 80
or more. The (b*-l) value is preferably from -3 to 15,
more preferably from -2 to 10.
Further, from the studies of the present inventors,
it has been found that, for improving the whiteness of
the ultimate shaped article, a polytrimethylene
terephthalate resin used for producing a shaped article
should exhibit not only excellent whiteness, but also
excellent resistance to discoloration during the heat-
ing of the resin (e.g., during the high temperature
drying, melt molding or the like of the resin). The
reason for this is not clear, but it is presumed that
the discoloration of the resin is caused by not only
the thermal decomposition of the resin per se, but also
certain substances or functional groups which are in-
evitably contained in the polytrimethylene terephtha-
late resin. It is considered that the above-mentioned
substances or functional groups are formed by heat de-
composition of a prepolymer (used in the production of
the polytrimethylene terephthalate resin) and/or the
polytrimethylene terephthalate resin. However, espe-
cially when the below-mentioned polymerization method
proposed by the present inventors is employed, it is
possible to obtain a polytrimethylene terephthalate
resin which has excellent resistance to the discolora-
tion during the heating. The reason for this is con-
sidered as follows. The proposed method is advanta-
geous not only in that the leakage of oxygen into the
polymerization reaction system can be suppressed,
thereby preventing the formation of the above-mentioned
substances and functional groups, but also in that the
surface area of the prepolymer being polymerized in the
polymerizer employed in this method is extremely large
as compared to the case of polymerizers which are con-
ventionally employed for the production of a poly-
trimethylene terephthalate resin, and the surface of
the prepolymer is efficiently renewed, so that the
above-mentioned substances or functional groups, if any,
can be easily withdrawn from the reaction system.
As a yardstick of the susceptibility to discolora-
tion by heat, the color of a polytrimethylene
terephthalate resin after heating at 180 °C for 2 4
hours in air can be used. In the present invention,
the polytrimethylene terephthalate resin heated under
the above-mentioned conditions needs to have a psycho-
metric lightness L-value (L-2) of 70 or more, and a
psychometric chroma b*-value (b*-2) of from -5 to 25.
The psychometric lightness L-value (L-2) is preferably
7 5 or more, more preferably 8 0 or more. The psychomet-
ric chroma b*-value (b*-2) is preferably from -4 to 21,
more preferably from -3 to 18, still more preferably
from -2 to 16.
In the present invention, for preventing the hy-
drolysis of the polytrimethylene terephthalate resin
even when the shaping of the resin which has not been
fully dried is performed, and for improving the
weatherability of a shaped article of the poly-
trimethylene terephthalate resin, it is preferred that
the polytrimethylene terephthalate resin of the present
invention has a terminal carboxyl group content of not
more than 30 meq/kg (based on the weight of the poly-
trimethylene terephthalate resin). The terminal car-
boxyl group content is preferably not more than 20
meq/kg, more preferably not more than 15 meq/kg, still
more preferably not more than 10 meq/kg. It is pre-
ferred that the terminal carboxyl group content is as
small as possible.
The polytrimethylene terephthalate resin of the
present invention can be used, for example, for produc-
ing an extrusion-molded article, such as a film or a
sheet. In the production of such an extrusion-molded
article, it is desired that the polytrimethylene
terephthalate resin simultaneously satisfies all of
such requirements as a very high molecular weight, a
very narrow molecular weight distribution and a very
low terminal carboxyl group content. Therefore, it is
preferred that the polytrimethylene terephthalate resin
for use in the production of an extrusion-molded arti-
cle has an intrinsic viscosity [r\] of from 1.25 to 2.5
dl/g, an Mw/Mn ratio of 2.6 or less and a terminal car-
boxyl group content of 20 meq/kg or less; it is more
preferred that the resin has an intrinsic viscosity [n]
of from 1.30 to 2.0 dl/g, an Mw/Mn ratio of 2.5 or less
and a terminal carboxyl group content of 15 meq/kg or
less; and it is still more preferred that the resin has
an intrinsic viscosity [?] of from 1.30 to 2.0 dl/g, an
Mw/Mn ratio of 2.4 or less and a terminal carboxyl
group content of 10 meg/kg or less. When the produc-
tion of the polytrimethylene terephthalate resin is
conducted by the below-mentioned polymerization method
proposed by the present inventors, the polymerization
rate is high and the surface area of the prepolymer be-
ing polymerized is large. Therefore, not only can the
polymerization degree be improved, but also the termi-
nal carboxyl group content can be lowered to a level
which has never been achieved by the conventional melt
polymerization. Further, in this method, the polymeri-
zation degree can be improved while maintaining a high
piston flowability (the "high piston flowability" means
a property that the flowing resin in the polymerizer
has no local variation of the flow rate, i.e., the
flowing resin as a whole has a uniform flow rate).
Thus, by the proposed method, it is possible to obtain
a polytrimethylene terephthalate resin having a narrow
molecular weight distribution, i.e., a resin which does
not contain polymers having largely different molecular
weights. When a polytrimethylene terephthalate resin
is produced by solid-phase polymerization, the resin
produced exhibits a high polymerization degree. How-
ever, in the solid-phase polymerization, the polymeri-
zation degree varies depending on the reaction site in
the pellets (i.e., whether the reaction site is at an
inner portion or outer portion of the pellets), and
also varies depending on the size and shape of the pel-
lets, so that it is very difficult to obtain a polymer
having a narrow molecular weight distribution. By the
proposed polymerization method, it has, for the first
time, become possible to produce a polytrimethylene
terephthalate resin which can be suitably used for the
commercial scale production of the above-mentioned ex-
trusion-molded article.
The polytrimethylene terephthalate resin of the
present invention, which is in a molten form obtained
immediately after the production thereof, can be spun
or shaped. Alternatively, the resin can be formed into
pellets, and then re-melted at the time of spinning or
shaping of the resin.
When the resin is used in the form of pellets, it
is desired that the amount of loss is small, and that
the pellets can be extruded uniformly by means of an
extruder. Therefore, it is preferred that each pellet
has an appropriate size, and that the amount of polymer
powder adhering to the surface of the pellets is small.
In the present invention, it is preferred that the
average weight of pellets is from 1 to 1,000 mg per
pellet. The pellets having such an average weight is
advantageous in that uniform extrusion of the pellets
by means of a extrusion molding machine becomes easy,
that the pellets can be handled with ease at the time
of transportation, drying and spinning thereof, and
that the drying rate of the pellets becomes fast. The
average weight of the pellets is more preferably from 5
to 500 mg per pellet, still more preferably from 10 to
200 mg per pellet. With respect to the shape of the
pellet, there is no particular limitation, and the
shape of the pellet may be any of a sphere, a rectangle,
a cylinder and a cone. However, from the viewpoint of
ease in handling of the pellets, it is preferred that
the length of the largest portion of each pellet is 15
mm or less, more advantageously 10 mm or less, still
more advantageously 5 mm or less.
With respect to the polymer powder adhering to the
surface of the pellets, it is preferred that the amount
of the polymer powder is in the range of from 0 to
0.5 % by weight, based on the total weight of the pel-
lets, which powder passes through a 30-mesh filter and
does not pass through a 300-mesh filter. When the
amount of the polymer powder is 0.5 % by weight or less,
not only is the loss decreased, but also it becomes
possible to prevent the clogging of a pneumatic line
(i.e., pipe line in which pellets are transferred by
gas) or a filter of an air-exhaust ventilator attached
to a dryer, and to suppress the pressure variation in
an extruder during the spinning, molding or compounding,
so that ultimate products having a uniform quality can
be easily obtained. It is preferred that the amount of
the polymer powder is as small as possible. From a
practical point of view, the amount of the polymer pow-
der is preferably in the range of from 0 to 0.2 % by
weight, more preferably from 0 to 0.1 % by weight,
still more preferably from 0 to 0.05 % by weight, based
on the total weight of the pellets.
Further, it is preferred that the pellets have a
crystallinity (Xc) of 0 to 40 %, wherein the crystal-
Unity is defined by the following formula:
Xc (%) = {?c X (?s - ?a)}/(?s X (?c - ?a)> X
100
wherein pa is 1.300 g/cm3 which is an amor-
phous density of trimethylene terephthalate
homopolymer, pc is 1.431 g/cm3 which is a
crystal density of trimethylene terephtha-
late homopolymer, and pE represents a den-
sity (g/cm3) of the pellets.
The above-mentioned crystal density of trimethyl-
ene terephthalate homopolymer (1.431 g/cm3) is a theo-
retical value which is calculated from the number of
crystal lattices of trimethylene terephthalate ho-
mopolymer. The above crystal density value (1.431
g/cm3) is described in "Poritorimechirenterefutareto no
Kesshoudanseiritsu (Crystal elasticity of poly-
trimethylene terephthalate)" ("Zairyou (Material)",
written by Katsuhiko Nakamae, Vol. 35, No. 396, p. 1067,
2000). Further, the amorphous density of trimethylene
terephthalate homopolymer (1.300 g/cm3) is obtained by
measuring the density of a sample amorphous polymer ob-
tained by quenching a trimethylene terephthalate ho-
mopolymer in a molten form. (With respect to the sample
polymer, it can be confirmed that the sample polymer is
amorphous, when no crystal peak is observed in the
analysis of the sample polymer by X-ray diffractorae-
try. )
When the pellets have the above-mentioned crystal-
linity, it becomes possible to prevent a problem which
is unique to a PTT and is unlikely to arise in the case
of other polyesters, such as a PET and a PBT (polybuty-
lene terephthalate), i.e., a problem that pellets be-
come brittle and generate a large amount of polymer
powder during the transportation of the pellets by
means of a pneumatic conveyor or a feeder. It is pre-
ferred that the crystallinity is from 0 to 35 %, more
advantageously from 0 to 30 %.
In the present invention, the crystallinity of a
pellet means an average value of crystallinity values
measured at different portions of the pellet. Specifi-
cally, for example, it is preferred that, when a sur-
face portion of the pellet is cut away from a central
portion of the pellet and crystallinities of these por-
tions are measured, both of the surface portion and the
central portion are in the above-mentioned crystallin-
ity range. Further, it is preferred that the differ-
ence in crystallinity between the surface portion and
the central portion is 40 % or less, more advanta-
geously 30 % or less, still more advantageously 20 % or
less .
For obtaining pellets having the above-mentioned
crystallinity, it is preferred that a polytrimethylene
terephthalate in a molten form, which is obtained by
polymerization, is extruded into a strand or a sheet,
and, subsequently, the obtained strand or sheet is im-
mersed in a coolant, such as water, to cool the strand
or sheet, followed by cutting of the strand or sheet to
obtain pellets. It is preferred that the temperature
of the coolant is 20 °C or less, more advantageously
15 °C or less, still more advantageously 10 °C or less.
From the viewpoint of economy and ease in handling of
the pellets, it is preferred to use water as a coolant.
Naturally, the temperature of water as a coolant is
0 °C or more. It is preferred that the cutting to ob-
tain pellets is performed with respect to the strand or
sheet solidified by cooling the extruded strand or
sheet to 55 ° C or lower within 120 seconds after the
extrusion.
Hereinbelow, the method for producing the poly-
trimethylene terephthalate resin of the present inven-
tion is described in detail.
The method for producing the polytrimethylene
terephthalate resin of the present invention comprises
the following steps (1) and (2):
(1) providing a molten form of a trimethylene
terephthalate prepolymer comprising:
90 to 100 mole % of trimethylene terephthalate re-
curring units, and
0 to 10 mole % of at least one monomer unit se-
lected from the group consisting of monomer units ob-
tained from comonomers which are other than the mono-
mers used for forming the trimethylene terephthalate
recurring units and which are copolymerizable with at
least one of the monomers used for forming the
trimethylene terephthalate recurring units,
the trimethylene terephthalate prepolymer having
an intrinsic viscosity [?] of from 0.2 to 2 dl/g, and
(2) polymerizing the molten form of a trimethylene
terephthalate prepolymer at a temperature which is
equal to or higher than the crystalline melting point
of the prepolymer and is not higher than 290 °C under
reduced pressure by the guide-wetting fall process in
which the prepolymer is allowed to fall along and in
contact with the surface of a guide so that polymeriza-
tion of the prepolymer is effected during the fall
thereof.
As mentioned above, a polymerizer which does not
have a rotary driving part has been proposed as a poly-
merizer for producing resins other than a poly-
trimethylene terephthalate. However, the melt
-polycondensation reaction for producing a poly-
trimethylene terephthalate greatly differs from the
melt-polycondensation reactions for producing other
types of polyesters, such as a PET and a PBT, and for
producing polyamides. Therefore, a practical produc-
tion of a polytrimethylene terephthalate cannot be re-
alized simply by employing the polymerizers which have
been used for the production of the other types of
polyesters and for the production of polyamides. The
important differences between the polytrimethylene
terephthalate, and polyamides and the other types of
polyesters (such as a PET and a PBT) are explained be-
low.
Firstly, both of the melt-polycondensation reac-
tion for producing polyamides and the melt
-polycondensation reaction for producing the other
types of polyesters are equilibrium reactions. However,
the equilibrium constants of the above two reactions
greatly differ from each other. In general, the equi-
librium constants of the melt-polycondensation reac-
tions for producing polyamides are in the order of 10 ,
whereas the equilibrium constants of the melt
-polycondensation reactions for producing the other
types of polyesters is approximately 1. Thus, despite
that both of the reactions for producing polyamides and
the reactions for producing the other types of polyes-
ters are polycondensation reactions, the equilibrium
constants of the reactions for producing the other
types of polyesters are extremely small as compared to
those of the reaction for producing the polyamides.
When an equilibrium constant of a certain reaction is
large, the reaction proceeds even without efficiently
withdrawing a by-product from the reaction system.
Therefore, it is easy to increase the polymerization
degrees of polyamides. With respect to the other types
of polyesters (such as a PET and a PBT), although the
equilibrium constants of the reactions for producing a
PET and a PBT are small, the by-products can be easily
withdrawn from the reaction systems, so that it is also
easy to increase the polymerization degree of each of a
PET and a PBT. The reason for this is as follows. In
the case of a PET, the PET has a satisfactory heat sta-
bility, and hence, a polymerization reaction for pro-
ducing the PET can be performed at a temperature (gen-
erally from 280 to 300 °C) which is much higher than
the boiling point (198 °C) of ethylene glycol which is
a by-product of the polymerization reaction. By per-
forming the polymerization at such a high temperature,
the vapor pressure of ethylene glycol can be increased
and, hence, the ethylene glycol can be easily withdrawn
from the reaction system. Also in the case of a PBT,
1,4-butanediol, which is a by-product of the polymeri-
zation reaction for producing a PBT, can be easily
withdrawn from the reaction system. The reason for
this has not yet been elucidated, but is considered as
follows. In the polymerization reaction system for
producing a PBT, 1,4-butanediol (which is a by-product
having a high boiling point) is converted into low
boiling point substances, such as tetrahydrofuran
(formed by hydrolysis) and butadiene (formed by heat
decomposition), which low boiling point substances can
be easily withdrawn from the reaction system.
As in the case of the polymerization reactions for
producing the other types of polyesters, the polymeri-
zation reaction for producing a polytrimethylene
terephthalate has a low equilibrium constant, and hence,
the by-produced trimethylene glycol (TMG) needs to be
efficiently withdrawn from the reaction system so as to
advance the polymerization reaction. The TMG has a
boiling point as high as 214 °C. On the other hand,
the polytrimethylene terephthalate is susceptible to
heat decomposition, so that the polymerization reaction
for producing the polytrimethylene terephthalate needs
to be performed at a low temperature. Therefore, it is
difficult to withdraw the TMG from the reaction system.
Further, when the polymerization degree of a poly-
trimethylene terephthalate becomes high, the following
disadvantage is caused. The viscosity of the poly-
trimethylene terephthalate also becomes high and, hence,
it becomes difficult to withdraw TMG from the reaction
system. In such a case, a heat decomposition of the
polytrimethylene terephthalate markedly occurs, so that
the reaction rate is lowered, and then, the polymeriza-
tion degree of the polytrimethylene terephthalate
starts to be lowered. If the polymerization reaction
is performed at a high temperature, the withdrawal of
the TMG becomes easier; however, the heat decomposition
of the polytrimethylene terephthalate markedly occurs,
thereby leading to the above-mentioned disadvantage
that, when the polymerization degree of a poly-
trimethylene terephthalate becomes high and the viscos-
ity of the polytrimethylene terephthalate also becomes
high, the reaction rate is lowered, and then, the po-
lymerization degree of the polytrimethylene terephtha-
late starts to be lowered.
However, as a result of the studies of the present
inventors, it has unexpectedly been found that, when a
molten form of a polytrimethylene terephthalate pre-
polymer having an intrinsic viscosity within the above-
mentioned specific range is polymerized by the above-
mentioned guide-wetting fall process at an appropriate
temperature under reduced pressure, a polytrimethylene
terephthalate can be produced without causing the prob-
lems accompanying the conventional polymerization meth-
ods for producing the other types of polyesters, such
as a PET, and for producing polyamides, i.e., methods
in which a polymerization is performed by allowing a
prepolymer to fall in the form of fibers or to fall
along and in contact with a guide, such as a wire.
With respect to the guide-wetting fall process,
reference can be made, for example, to U.S. Patent Nos .
5,589,564, 5,840,826, 6,265,526 and 6,320,015.
The features of the method of the present inven-
tion are described below.
Firstly, for obtaining a polytrimethylene
terephthalate resin having a high polymerization degree
only by melt polymerization, it is required not only to
suppress the heat decomposition of the PTT, but also to
remove efficiently a TMG (by-product of the reaction
for producing the PTT). In the method of the present
invention, these requirements are satisfied by perform-
ing the polymerization by allowing a prepolymer to fall
along and in contact with the guide at an appropriate
temperature under reduced pressure to thereby increase
the surface area of the prepolymer. Further, by allow-
ing the polymer to fall along and in contact with a
guide, it becomes possible to prevent the disadvanta-
geous fluctuation of qualities of the products, wherein
the fluctuation occurs due to the breakage of the poly-
mer flow in the polymerizer.
Secondly, for preventing the discoloration of the
polymer which is caused by the entrance of oxygen and a
sealing liquid into the polymer, it is required to em-
ploy a polymerizer having no rotary driving part at a
portion of the polymerizer, which portion contains a
gaseous phase during the polymerization. In the guide-
wetting fall process, there is no need for the polymer-
izer to have a rotary driving part in such a gaseous
phase portion of the polymerizer, and the polymerizer
exhibits an excellent sealability under a highly vac-
uumized condition, so that a discoloration caused by
leakage of oxygen into the polymerizer can be almost
completely prevented. Further, since the polymerizer
has no rotary driving part, a mixing of a sealing liq-
uid into a polymer would not occur, and the maintenance
of the polymerizer is easy. Thus, a high quality poly-
trimethylene terephthalate which is free from a disad-
vantageous discoloration can be obtained.
Thirdly, for stably producing a polytrimethylene
terephthalate resin on a commercial scale, it is re-
quired to suppress the foaming of the prepolymer intro-
duced into the polymerization reaction zone, so as to
prevent the staining of the lower surface of the perfo-
rated plate and inner wall of the polymerizer. In the
method of the present invention, this requirement is
satisfied by introducing a prepolymer having an in-
creased viscosity, more specifically by polymerizing a
prepolymer having a high intrinsic viscosity within a
specific range at a specific low temperature. By vir-
tue of this feature, it becomes possible to suppress
the lowering of the quality of the polytrimethylene
terephthalate resin, which is caused by the mixing or
entrance of the stain into the polytrimethylene
terephthalate resin.
Thus, by the method of the present invention, the
problems accompanying the conventional techniques for
performing a melt-polycondensation to produce a poly-
trimethylene terephthalate resin can be solved, and it
becomes possible to produce resin which is free from a
discoloration caused by heat decomposition, and which
has high quality and high polymerization degree. Such
effects are unexpected from the conventional techniques
for performing polymerization reactions for producing
polyamides and the other types of polyesters.
In the present invention, it is necessary to in-
troduce a trimethylene terephthalate prepolymer in a
molten form through the holes of the perforated plate
into the polymerization reaction zone at a temperature
which is equal to or higher than the crystalline melt-
ing point of the prepolymer and is not higher than
290 °C, wherein the prepolymer has an intrinsic viscos-
ity [r|] of from 0.2 to 2 dl/g.
In the present invention, the "trimethylene
terephthalate prepolymer" means a polycondensation
product which has a molecular weight lower than the fi-
nal polytrimethylene terephthalate resin obtained
therefrom.
In the present invention, it is important to sup-
press the scattering of the prepolymer in the polymeri-
zation reaction zone, which is caused by the vigorous
foaming of the prepolymer. In the present invention,
for suppressing the scattering of the prepolymer, and
for effectively removing the by-produced TMG from the
reaction system, it is essential to introduce the
above-mentioned prepolymer having a specific intrinsic
viscosity [r|] into the polymerization reaction zone at
the above-mentioned specific temperature. When the
scattering of the prepolymer is caused by the vigorous
foaming of the prepolymer introduced through the holes
of the perforated plate into the polymerization reac-
tion zone, the polymer adheres to the lower surface of
the perforated plate and the inner wall of the polymer-
izer, thereby staining them. The prepolymer which ad-
heres to the lower surface of the perforated plate and
the inner wall of the polymerizer remains in the poly-
merizer for a long period of time, and hence, suffers
heat decomposition to form a discolored low molecular
weight product and/or a discolored modified product.
When such discolored products get mixed with the final
48
polytrimethylene terephthalate resin, the quality of
the resin is lowered. For suppressing the scattering
of the prepolymer caused by the vigorous foaming
thereof, it is necessary that the prepolymer has an in-
trinsic viscosity [?] of 0.2 or more. Further, for
constantly producing a resin having a narrow molecular
weight distribution, it is preferred that the prepoly-
mer has a high viscosity. The reason for this is as
follows. In the guide-wetting fall process employed in
the present invention, a fluctuation of polymerization
degree of the prepolymer being polymerized may occur
due to the fluctuation of the falling rate of the pre-
polymer and the fluctuation of the level of surface re-
newal of the prepolymer, leading to a broad molecular
weight distribution of the final resin. For preventing
such fluctuation of the falling rate of the prepolymer
and fluctuation of the level of surface renewal of the
prepolymer, it is preferred that the viscosity of the
prepolymer is high.
However, on the other hand, when the prepolymer
has too high an intrinsic viscosity, it becomes diffi-
cult to withdraw efficiently the by-produced TMG from
the reaction system. Further, when the intrinsic vis-
cosity is too high, the amount of the by-produced TMG
becomes extremely small, so that it becomes difficult
to cause an appropriately mild foaming of the prepoly-
mer during the fall thereof in the polymerizer, which
foaming of the prepolymer is an important feature of
the polymerization method of the present invention.
Thus, it becomes difficult to improve the polymeriza-
tion degree of the polytrimethylene terephthalate resin.
For preventing the above disadvantages, it is nec-
essary that the prepolymer has an intrinsic viscosity
[?] of 2 dl/g or less. It is preferred that the pre-
polymer has an intrinsic viscosity [?] of from 0.3 to
1.8 dl/g, more advantageously from 0.4 to 1.5 dl/g.
In addition, for preventing disadvantages (e.g.,
vigorous foaming of the prepolymer, and heat decomposi-
tion of the prepolymer) which are caused by the low
viscosity of the prepolymer and which lead to a lower-
ing of the quality of the polytrimethylene terephtha-
late resin, it is necessary that the temperature of the
prepolymer introduced into the polymerization reaction
zone be 290 °C or less. On the other hand, for uni-
formly introducing the prepolymer into the polymeriza-
tion reaction zone without solidifying the prepolymer
in the holes of the perforated plate, and for causing
the prepolymer as a whole to fall uniformly along and
in contact with the guide without partially solidifying
the prepolymer during the fall thereof, it is necessary
that the temperature of the prepolymer introduced into
the polymerization reaction zone be equal to or higher
than the crystalline melting point of the prepolymer.
In the present invention, the crystalline melting
point of the prepolymer means a temperature at which an
endothermic peak ascribed to the melting of a crystal
is observed in a differential scanning calorimetry
(DSC) chart of the prepolymer, wherein the DSC chart is
obtained by means of an input compensation-type differ-
ential scanning calorimeter (trade name: Pyris 1; manu-
factured and sold by Perkin Elmer, Inc., U.S.A.) under
the following conditions:
Measuring temperature: 0 to 280 °C, and
Rate of temperature elevation: 10 "C/min.
The temperature of the prepolymer introduced into
the polymerization reaction zone is preferably 5 ° C or
more higher than the crystalline melting point of the
prepolymer and not higher than 280 °C, more preferably
10 ° C or more higher than the crystalline melting point
of the prepolymer but not higher than 27 5 ° C, still
more preferably 15 oC or more higher than the crystal-
line melting point of the prepolymer but not higher
than 26 5 °C.
In the present invention, the above-mentioned per-
forated plate is a plate having a plurality of
through-holes through which the prepolymer is intro-
duced into the polymerization reaction zone. There is
no particular limitation with respect to the thickness
of the perforated plate. However, the thickness of the
perforated plate is generally in the range of from 0.1
to 300 mm, preferably from 1 to 200 mm, more preferably
from 5 to 150 mm. The perforated plate needs to have a
strength sufficient to sustain the pressure inside the
chamber of the polymerizer, into which the molten pre-
polymer is fed. Also, when the guide(s) in the polym-
erization reaction zone of the polymerizer is (are)
hung from the perforated plate, it is necessary that
the perforated plate can sustain the weight of the
guide(s) and the molten prepolymer which is falling
along and in contact with the surface of the guide(s).
For this reason, it is preferred that the perforated
plate is reinforced with a rib. The shape of the hole
of the perforated plate is generally selected from a
circle, an ellipse, a triangle, a slit, a polygon, a
star and the like. The area at the opening of each
hole is generally in the range of from 0.01 to 100 cm2,
preferably from 0.05 to 10 cm , more preferably from
0.1 to 5 cm . Further, nozzles or the like may be at-
tached to the holes of the perforated plate. The dis-
tance between mutually adjacent holes of the perforated
plate is generally from 1 to 500 mm, preferably from 25
to 100 mm, as measured between the respective centers
of the mutually adjacent holes. The perforated plate
may have tubes attached thereto, such that the hollow
portions of the tubes serve as the holes of the perfo-
rated plate. Further, the hole of the perforated plate
may have a tapered configuration. It is preferred that
the size and shape of the hole are determined so that
the pressure loss which occurs when the molten form of
a prepolymer passes through the perforated plate is
from 0.01 to 5 MPa, more preferably from 0.1 to 5 MPa.
When the pressure loss is in the above-mentioned range,
it becomes easy to obtain a resin having a further im-
proved polymerization degree (the reason for this is
not clear). In general, it is preferred that the mate-
rial used for the perforated plate is selected from the
group consisiting of metallic materials, such as
stainless steel, carbon steel, Hastelloy, nickel, tita-
nium, chromium and alloys other than mentioned.
Further, it is preferred that a filter is provided
in the flowing path of the prepolymer in the polymer-
izer at a point which is upstream of the perforated
plate. The reason for this is that the filter can be
used for removing an impurity, if any, which is con-
tained in the prepolymer, and which may cause the clog-
ging of the holes of the perforated plate. The type of
filter is appropriately selected so that the impurity
having a size larger than the diameter of the holes of
the perforated plate can be removed, and that the fil-
ter is not destroyed by the passage of the prepolymer
therethrough.
Examples of methods for causing the molten pre-
polymer to pass downwardly through a perforated plate
provided in the polymerizer and fall along and in con-
tact with the guide include a method in which the pre-
polymer is allowed to fall only by liquid head or by
gravity, and a method in which the prepolymer on the
perforated plate is pressurized by using a pump or the
like to thereby force the molten prepolymer to pass
downwardly through a perforated plate. It is preferred
that the fluctuation of the amount of falling prepoly-
mer is suppressed by means of a pump which has a meas-
uring ability, such as a gear pump.
There is no particular limitation with respect to
the number of holes of the perforated plate. The ap-
propriate number of holes of the perforated plate var-
ies depending on the polymerization conditions (such as
a polymerization temperature and a polymerization pres-
sure), the amount of the catalyst used, the range of
the molecular weight of the prepolymer, and the like.
For example, when it is intended to produce the resin
at a rate of 100 kg/hr, it is preferred that the perfo-
rated plate has 1 to 104 holes, more advantageously 2
to 102 holes.
In the present invention, it is necessary that the
prepolymer which has been introduced through the holes
of the perforated plate into the polymerization reac-
tion zone is polymerized by allowing the prepolymer to
fall along and in contact with the guide in the polym-
erization reaction zone under reduced pressure. It is
preferred that the prepolymer in the polymerization re-
action zone is in a foaming state such that the bubbles
formed in the prepolymer in the polymerization reaction
zone would not be broken instantaneously. It is espe-
cially preferred that the prepolymer at a lower portion
of the guide is in a foaming state. Needless to say,
it is most preferred that the whole of the prepolymer
in the polymerization reaction zone is in a foaming
state.
The guide used in the method of the present inven-
tion may be any of a wire, a chain, a wire mesh (each
of the chain and the wire mesh is made by combining
wires), a jungle gym-like body (having a lattice struc-
ture composed of wires), a flat or curved thin plate, a
perforated plate, and a filler column (which is formed
by regularly or irregularly piling fillers together).
For efficiently withdrawing TMG from the reaction
system, it is preferred that the surface area of the
falling prepolymer is increased. Therefore, it is pre-
ferred that the guide is a wire, a chain, a wire mesh
or a jungle gym-like body. Further, for more effi-
ciently withdrawing TMG from the reaction system to
further improve the polymerization rate, it is espe-
cially preferred not only to increase the surface area
of the guide, but also to form concave portion(s)
and/or convex portion(s) on the surface of the guide
which are arranged along the length thereof, so as to
promote the agitation and surface renewal of the pre-
polymer falling along and in contact with the surface
of the guide. Thus, it is preferred that the guide has
at least one portion selected from the group consisting
of a concave portion, a convex portion and a perforated
portion. Specifically, it is preferred to use a guide
having a structure which hampers the fall of the poly-
mer, such as a chain, a jungle gym-like body or a wire
having concavo-convex portions on the surface thereof
along which the prepolymer falls. Needless to say, the
above-mentioned guides can be used in combination.
In the present specification, the term "wire"
means a body in which the ratio of the length of the
body to the average perimeter of the cross-section of
the body is very large. There is no particular limita-
tion with respect to the cross-sectional area of the
wire. However, in general, the cross-sectional area is
in the range of from 10-3 to 102 cm2 , preferably from
10-2 to 10 cm2, more preferably from 10"1 to 1 cm2.
There is no particular limitation with respect to the
shape of the cross-section of the guide, and the shape
is generally selected from a circle, an ellipse, a tri-
angle, a quadrangle, a polygon, a star and the like.
The shape of the cross-section of the wire may be uni-
form or may vary along the length of the wire. The
wire may be hollow. Further, the wire may be made of a
single strand, or made of a plurality of strands,
wherein, for example, the strands are twisted together.
The surface of the wire may be smooth or may have con-
cavo-convex portions as mentioned above, a locally pro-
truding portion or the like. There is no particular
limitation with respect to the material used for the
wire, but the material is generally selected from the
group consisting of, for example, stainless steel, car-
bon steel, Hastelloy, nickel, titanium, chromium and
other alloys. If desired, the wire may be subjected to
surface treatment. Examples of surface treatments in-
elude plating, lining, passivation, and washing with an
acid.
The "wire mesh" means a body which is made by com-
bining the above-mentioned wires so as to form a lat-
tice. The wires can be linear or curved, and the angle
between the combined wires can be appropriately se-
lected. With respect to the area ratio of the wires of
the wire mesh to the open spaces (which ratio is meas-
ured with respect to the projected image of the wire
mesh), there is no particular limitation, but the area
ratio is generally in the range of from 1/0.5 to
1/1,000, preferably from 1/1 to 1/500, more preferably
from 1/5 to 1/100. It is preferred that the area ratio
of the wire mesh does not vary horizontally relative to
the vertical direction of the wire mesh. Further, it
is preferred that the area ratio of the wire mesh along
the vertical length of the wire mesh does not vary or
varies such that, when the wire mesh is provided as the
guide in the polymerizer, the area of each open space
at a lower portion of the wire mesh becomes smaller
than that at an upper portion of the wire mesh (which
means that the area ratio at a lower portion of the
wire mesh becomes larger than that at an upper portion
of the wire mesh).
In the present invention, the "chain" means a body
in which rings formed by the above-mentioned wires are
linked together. The shape of rings can be a circle,
an ellipse, a rectangle, a square or the like. The
rings can be linked in one dimension, two dimensions or
three dimensions.
In the present invention, the term "jungle gym
-like body" means a material in which the above
-mentioned wires are three-dimensionally combined with
one another so as to form a lattice. The wires used
can be linear or curved, and the angle between the com-
bined wires can be appropriately selected.
Examples of wires having convex portion(s) and/or
concave portion(s) on the surface thereof (along and in
contact with which the prepolymer is allowed to fall)
include a wire to which a rod having a circular or po-
lygonal cross-section is attached such that the rod ex-
tends substantially vertically of the wire, and a wire
to which a disc-shaped or cylindrical-shaped body is
attached such that the wire penetrates through the
disc-shaped or cylindrical-shaped body around the cen-
ter thereof. It is preferred that the convex portion
has a height which is at least 5 mm larger than the
diameter of the wire. As a specific example of wires
having convex portion(s), there can be mentioned a wire
to which a plurality of discs are attached at intervals
of from 1 to 500 mm, in which each disc has a diameter
which is at least 5 mm larger than the diameter of the
wire and not more than 100 mm, and a thickness of from
approximately 1 to 10 mm.
With respect to the chain, jungle gym-like body
and wire having concavo-convex portions on the surface
thereof, which are used as the guides, there is no par-
ticular limitation on the volume ratio of the skeleton
of the guide (e.g., wires used to form the guide) to
the open spaces in the guide. However, in general, the
volume ratio is in the range of from 1/0.5 to 1/10 ,
preferably from 1/10 to 1/10 , more preferably from
1/102 to 1/105. It is preferred that the volume ratio
does not vary horizontally of the downwardly extending
guide. Further, it is preferred that the volume ratio
of the downwardly extending guide along the length of
the guide does not vary or varies such that, when the
guide is provided in the polymerizer, the volume ratio
at a lower portion of the guide becomes larger than
that at an upper portion of the guide.
The above-mentioned guides can be used individu-
ally or in combination, depending on the configuration
of the guides. When the guide is a wire or a linear
chain, the number of guide(s) used is generally in the
range of from 1 to 100,000, preferably from 3 to 50,000.
When the guide is a wire mesh, a chain formed by two-
diraensionally combining the wires, a thin plate or a
perforated plate, the number of guide(s) used is gener-
ally in the range of from 1 to 1,000, preferably from 2
to 100. When the guide is a chain formed by three-
dimensionally combining the wires, a jungle gym-like
body or a filler column, the number of the guide(s) can
be appropriately selected depending on the sizes of the
polymerizer and the polymerization reaction zone where
the guide(s) is (are) provided.
When a plurality of guides are used, it is pre-
ferred to arrange the guides so as for the guides not
to contact with each other by using a spacer or the
like.
In the present invention, in general, the prepoly-
mer is introduced through at least one hole of the per-
forated plate into the polymerization reaction zone
where the prepolymer is allowed to fall along and in
contact with the guide. The number of holes of the
perforated plate can be appropriately selected depend-
ing on the shape of the guide. In the method of the
present invention, the prepolymer which has passed
through a single hole of the perforated plate can be
allowed to fall along and in contact with a plurality
of guides. However, for causing the prepolymer to fall
uniformly so as to obtain a resin having a narrow mo-
lecular weight distribution constantly, it is preferred
that the number of guide(s) along which the prepolymer
(which has passed through a single hole of the perfo-
rated plate) is allowed to fall is small. For example,
when the guide is a wire, it is preferred that the num-
ber of guide(s) along which the prepolymer (which has
passed through a single hole of the perforated plate)
is allowed to fall is 3 or less. There is no particu-
lar limitation with respect to the position of the
guide(s) in the polymerizer so long as the prepolymer
can fall along and in contact with the guide(s), and
the guide(s) can be provided such that the guide passes
through the hole of the perforated plate or is hung be-
low the hole of the perforated plate.
With respect to the distance over which the molten
prepolymer (having passed through the holes of the per-
forated plate) falls along and in contact with the sur-
face of the guide, the distance is preferably from 0.3
to 50 m, more preferably from 0.5 to 20 m, still more
preferably from 1 to 10 m.
The flow rate of prepolymer passing through the
holes of the perforated plate is preferably in the
range of from 10+2 to 10 liters/hr per hole of the
perforated plate, more preferably from 0.1 to 50 li-
ters/hr per hole of the perforated plate. When the
flow rate of prepolymer is within the above-mentioned
range, it becomes possible to prevent a marked lowering
of the polymerization rate and the productivity of the
final resin.
In the method of the present invention, it is pre-
ferred that the average falling time of the prepolymer
is in the range of from 10 seconds to 100 hours, more
preferably from 1 minute to 10 hours, still more pref-
erably from 5 minutes to 5 hours, most preferably from
20 minutes to 3 hours.
In the method of the present invention, as men-
tioned above, it is necessary that the polymerization
reaction (performed by allowing the prepolymer to fall
along and in contact with the guide) be performed under
reduced pressure. By performing the polymerization re-
action under reduced pressure, TMG (which is by-
produced during the polymerization reaction) is effi-
ciently withdrawn from the reaction system so as to ad-
vance the polymerization reaction. The reduced pres-
sure means a pressure which is lower than the atmos-
pheric pressure. Generally, it is preferred that the
polymerization is conducted under a pressure of 100,000
Pa or less, more preferably 10,000 Pa or less, still
more preferably 1,000 Pa or less, most preferably 100
Pa or less. There is no particular limitation with re-
spect to the lower limit of the pressure under which
the polymerization is conducted. However, from the
viewpoint of the size of the equipment for reducing the
pressure in the reaction system, it is preferred that
the pressure is 0.1 Pa or more.
Further, an inert gas which does not adversely af-
fect the polymerization reaction can be introduced into
the reaction system under reduced pressure, so as to
remove the by-produced TMG in such a form as entrained
by the inert gas . In the method of the present inven-
tion, the inert gas is generally used in an amount of
from 0.005 to 100 mg per gram of the polytrimethylene
terephthalate resin withdrawn from the polymerization
reaction zone.
Conventionally, it has been understood that the
introduction of inert gas into a polycondensation reac-
tion system lowers the partial pressure of a by-product
formed during the polycondensation reaction, thereby
displacing the equilibrium of the reaction in the di-
rection of the desired product formation. However, in
the present invention, the inert gas is introduced into
the reaction zone only in a very small amount, and
hence, the improvement of the polymerization rate by
the lowering of partial pressure of a by-product cannot
be expected. Thus, from the conventional understanding,
the function of the inert gas used in the method of the
present invention cannot be explained. From the stud-
ies of the present inventors, it has surprisingly been
found that the introduction of inert gas into the po-
lymerization reaction zone causes an appropriately mild
foaming of the molten prepolymer on the guide, so that
not only is the surface area of the molten prepolymer
greatly increased, but also the surface renewal of the
prepolymer vigorously occurs without staining the inner
wall of the polymerizer. It is presumed that a vigor-
ous movement of the prepolymer at various portions (in-
cluding inner and surface portions) thereof causes the
remarkable improvement in the polymerization rate.
As the inert gas introduced into the polymeriza-
tion reaction zone, it is preferred to use inert gas
which does not cause discoloration, denaturation or de-
composition of the polymer. Preferred examples of in-
ert gases include nitrogen gas, argon gas, helium gas,
carbon dioxide gas and a lower hydrocarbon gas. Need-
less to say, a mixture of the above mentioned gases can
also be used in the present invention. As the inert
gas, it is more preferred to use nitrogen gas, argon
gas, helium gas and/or carbon dioxide gas. Among these
gases, nitrogen gas is most preferred from the view-
point of availability.
In the present invention, the amount of inert gas
introduced into the polymerization reaction zone may be
very small. Specifically, it is preferred that the
amount of inert gas is in the range of from 0.05 to 100
mg per gram of the final resin withdrawn from the po-
lymerization reaction zone. By using the inert gas in
an amount of 0.05 mg or more per gram of the final res-
in withdrawn from the polymerization reaction zone, it
becomes possible to foam the polymer satisfactorily so
as to increase the polymerization degree. On the other
hand, by using the inert gas in an amount of 100 mg or
less, it becomes easy to maintain the appropriate
reduced pressure in the polymerization reaction zone.
It is preferred that the amount of inert gas introduced
into the polymerization reaction zone is in the range
of from 0.1 to 50 mg per gram of the final resin with-
drawn from the polymerization reaction zone, more ad-
vantageously from 0.2 to 10 mg.
Examples of methods for introducing the inert gas
into the polymerization reaction zone include a method
in which at least a part of the inert gas is introduced
to the polymerization reaction zone, independently from
the feeding of the trimethylene terephthalate prepoly-
mer to the polymerization reaction zone, and a method
in which at least a part of the inert gas is introduced
to the polymerization reaction zone in such a form as
absorbed and/or contained in the trimethylene
terephthalate prepolymer, such that the inert gas is
caused to be discharged from the prepolymer under re-
duced pressure in the polymerization reaction zone.
These two methods can be used individually or in combi-
nation .
In the present invention, it is preferred to em-
ploy the above-mentioned method in which at least a
part of the inert gas is introduced to the polymeriza-
tion reaction zone in such a form as absorbed by the
trimethylene terephthalate prepolymer or in such a form
as contained in the trimethylene terephthalate prepoly-
mer. The former means that the inert gas is dissolved
in the prepolymer, and is not present in the form of
bubbles in the prepolymer. On the other hand, the lat-
ter means that the inert gas is present in the form of
bubbles in the prepolymer. When the inert gas is pre-
sent in the form of bubbles in the prepolymer, it is
preferred that the size of each bubble is as small as
possible. It is preferred that the average diameter of
each bubble is 5 mm or less, more advantageously 2 mm
or less.
When the inert gas is introduced to the polymeri-
zation reaction zone, independently from the feeding of
the prepolymer to the polymerization reaction zone, it
is preferred to feed the inert gas to the polymerizer
at a position remote from the perforated plate and
close to the outlet for withdrawing the final resin.
Further, it is preferred to feed the inert gas to the
polymerizer at a position remote from the vent to which
a vacuum gas discharge line is connected.
On the other hand, examples of methods for causing
the inert gas to be absorbed by and/or contained in the
prepolymer include a method using any of conventional
absorption devices, such as a packed column type ab-
sorption device, a tray-containing column type absorp-
tion device, a spraying device-containing column type
absorption device (in which a liquid is sprayed in a
gas to be absorbed in the liquid), a turbulent contact
absorption device, a gas-liquid film cross-contacting
type absorption device, a high-speed rotary flow type
absorption device, an absorption device utilizing me-
chanical force, which are described in "Kagaku Souchi
Sekkei"Sousa Shiriizu No. 2, Kaitei Gasu Kyushu (Design
and Operation of Chemical Devices, No. 2, Gas Absorp-
tion (Revised Version))", pp. 49-54 (published on March
15, 1981 by Kagaku Kogyosha, Inc., Japan); and a method
in which the inert gas is injected into the prepolymer
in a conduit for transferring the prepolymer to the po-
lymerizer. Most preferred is a method using a device
in which the prepolymer is allowed to fall along and in
contact with the surface of a guide in an atmosphere of
inert gas to thereby cause the prepolymer to absorb the
inert gas during the fall thereof. In this method, in-
ert gas having a pressure higher than the pressure in-
side the polymerizer is introduced into the gas absorp-
tion device. The pressure of the inert gas introduced
into the gas absorption device is preferably from 0.01
to 1 MPa, more preferably from 0.05 to 0.5 MPa, still
more preferably from 0.1 to 0.2 MPa.
In both of the above-mentioned methods for intro-
ducing the inert gas into the polymerization reaction
system, it is preferred that at least a part of the
prepolymer falling in the polymerization reaction zone
is in a foaming state. It is especially preferred that
the prepolymer at a lower portion of the polymerization
reaction zone is a forming state. Needless to say, it
is most preferred that the whole of the prepolymer fal-
ling in the polymerization reaction zone is in a foam-
ing state. In the present invention, the "foaming
state" encompasses both a state in which the formed
bubbles are immediately broken and a state in which the
formed bubbles are maintained for a relatively long
time.
In the method of the present invention, it is nec-
essary that the temperature in the polymerization reac-
tion zone is equal to or higher than the crystalline
melting point of the prepolymer, and not higher than
290 °C. By performing the polymerization reaction at a
temperature which is equal to or higher than the crys-
talline melting point of the prepolymer, it becomes
easy to cause the prepolymer to fall stably without
causing the prepolymer to get too viscose or solidified.
Further, by performing the polymerization reaction at a
temperature which is not higher than 290 °C, a discol-
oration of the prepolymer caused by heat decomposition
of the prepolymer is suppressed, and hence, a poly-
trimethylene terephthalate resin having high quality
can be easily obtained. It is preferred that the dif-
ference between the temperature in the polymerization
reaction zone (which is within the above-mentioned
range) and the temperature of the molten prepolymer in-
troduced into the polymerization reaction zone through
the perforated plate is 20 °C or less, more advanta-
geously 10 °C or less, still more advantageously 5 °C
or less, and it is most preferred that the temperature
in the polymerization reaction zone and the temperature
of the molten prepolymer introduced into the polymeri-
zation reaction zone are the same. The temperature in
the polymerization reaction zone can be controlled by
adjusting the temperature of a heater or a jacket which
is provided on the inner wall of the polymerizer, or by
adjusting the temperature of a heater or a heating me-
dium which is provided inside the guide.
In the present invention, for improving the polym-
erization rate, it is preferred that the prepolymer
contains a polycondensation catalyst.
Examples of polycondensation catalysts include ti-
tanium alkoxides, such as titanium tetrabutoxide and
titanium tetraisopropoxide; titanium compounds, such as
titanium dioxide and a double salt of titanium dioxide
and silicon dioxide; antimony compounds, such as dian-
timony trioxide and antimony acetate; and tin compounds,
such as butyl stannate, butyltin tris(2-ethylhexoate)
and tin 2-ethylhexanoate. Of these, titanium tetrabu-
toxide and tin 2-ethylhexanoate are especially pre-
ferred from the viewpoint of improvement in the polym-
erization reaction rate and the color of the final
resin. These catalysts can be used individually or in
combination. It is preferred that the polycondensation
catalyst is contained in the prepolymer in an amount of
from 0.001 to 1 % by weight, more advantageously from
0.005 to 0.5 % by weight, still more advantageously
from 0.01 to 0.2 % by weight, based on the weight of
the prepolymer.
In the present invention, for obtaining a poly-
trimethylene terephthalate resin having a very high mo-
lecular weight, it is preferred that the polymerization
degree of the prepolymer is increased, and that the
terminal carboxyl group ratio of the prepolymer is low-
ered, wherein the terminal carboxyl group ratio is a
molar ratio (%) of the terminal carboxyl groups at the
terminals of the prepolymer to the total of terminal
groups of the prepolymer. It is preferred that the
prepolymer has an intrinsic viscosity [?] of 0.5 or
more. By using a prepolymer having such a high intrin-
sic viscosity, it becomes possible to obtain a desir-
able falling rate of the prepolymer and a desirable
foaming state of the prepolymer, thereby greatly im-
proving the polymerization rate. It is preferred that
the prepolymer has an intrinsic viscosity [r|] of 0.55
or more, more preferably 0.60 dl/g or more.
On the other hand, it is preferred that the pre-
polymer has a terminal carboxyl group ratio of 50 % or
less. The terminal carboxyl group ratio is calculated
by the following formula:
Terminal carboxyl group ratio (%)
= (terminal carboxyl group content)/(total terminal
group content) x 100
wherein:
the terminal carboxyl group content is the molar
amount of carboxyl group per kg of a sample, and
the total terminal group content is the total mo-
lar amount of terminal groups per kg of a sample.
When the terminal carboxyl group ratio is 50 % or
less, the polymerization reaction rate can be improved,
so that a resin having a high molecular weight can be
obtained and that a discoloration of the resin can be
suppressed. The terminal carboxyl group ratio is more
preferably 30 % or less, still more preferably 20 % or
less, most preferably 0 %.
The above-mentioned prepolymer which is suitable
for producing a resin having a high molecular weight
has a high intrinsic viscosity. Therefore, when such a
prepolymer is used, it becomes difficult not only to
withdraw TMG from the reaction system due to the high
viscosity of the prepolymer, but also to produce the
prepolymer by means of a conventional vertical agita-
tion type polymerizer. In addition, for decreasing the
terminal carboxyl group ratio of the prepolymer, it is
necessary to improve the polymerization rate and sup-
press heat decomposition. Therefore, it is preferred
that the prepolymer is produced by means of a horizon-
tal agitation type polymerizer equipped with one or two
stirrers, each having a large surface area and a high
surface renewal efficiency.
The method of the present invention can be prac-
ticed in either a manner in which the prepolymer in a
molten form is continuously fed into the polymerizer
and introduced into the polymerization reaction zone
through the holes of the perforated plate, and the pre-
polymer in a molten form is allowed to fall along and
in contact with the guide to thereby perform a polym-
erization, and all of the resultant resin is withdrawn
form the polymerizer; or a manner in which a part of
the resin (obtained by the above-mentioned polymeriza-
tion performed by allowing the prepolymer to fall along
and in contact with the guide) is recycled to the poly-
merizer and subjected to further polymerization. How-
ever, it is preferred to employ the former (in which,
all of the obtained resin is withdrawn from the poly-
merizer). When the method of the present invention is
practiced in the above-mentioned manner in which a part
of the obtained resin is recycled to the polymerizer
and subjected to further polymerization, for suppress-
ing the heat decomposition of the resin which occurs at
a reservoir portion of the polymerizer (i.e., a bottom
portion of the polymerizer where the resin obtained by
the polymerization is accumulated.) and a conduit for
recycling of the resin, it is preferred to reduce the
retention times and lower the temperatures at the
above-mentioned reservoir portion and conduit.
Hereinbelow, the method for producing a poly-
trimethylene terephthalate prepolymer which is used in
the present invention is described in detail.
As representative examples of preferred methods
for producing the polytrimethylene terephthalate pre-
polymer on a commercial scale, there are the following
two methods which differ in the materials used. In one
of the methods, a lower alcohol diester of terephthalic
acid and TMG are subjected to transesterification reac-
tion to obtain bis(3-hydroxylpropyl)terephthalate
(hereinafter, referred to as "BHPT") which is an inter-
mediate of a PTT, and the obtained BHPT is subjected to
a polycondensation reaction, thereby obtaining a PTT
prepolymer (hereinafter, this method is referred to as
a "transesterification method"). In the other method,
terephthalic acid and TMG are subjected to an esterifi-
cation reaction to obtain BHPT, and the obtained BHPT
is subjected to a polycondensation reaction as in the
above-mentioned transesterification method, thereby ob-
taining a PTT prepolymer (hereinafter, this method is
referred to as "direct esterification method").
Further, the production of the polytrimethylene
terephthalate prepolymer can be performed in either a
batchwise manner in which all of the raw materials are
charged into the polymerizer at once and reacted to-
gether simultaneously to obtain a PTT prepolymer, or a
continuous manner in which the raw materials are con-
tinuously fed into the polymerizer to continuously ob-
tain a PTT prepolymer. In the present invention, it is
preferred that the production of the PTT prepolymer is
performed in a continuous manner, and that the resul-
tant prepolymer is continuously polymerized by the
method of the present invention.
In the present invention, the above-mentioned BHPT
may contain unreacted raw materials (such as
terephthalic acid, a lower alcohol diester of
terephthalic acid and TMG) and a PTT oligomer. However,
it is preferred that the BHPT comprises 70 % by weight
or more of the BHPT and/or a low molecular weight PTT
oligomer, based on the total weight of the BHPT, and
the above-mentioned unreacted raw materials and PTT
oligomer.
Hereinbelow, explanations are made on some exam-
ples of the methods for obtaining the BHPT.
First, an explanation is made on the "transesteri-
fication method". In the transesterification method,
the BHPT is produced by subjecting dimethyl terephtha-
late (hereinafter, referred to as "DMT") (which is a
lower alcohol diester of terephthalic acid) and TMG to
a transesterification reaction at 150 to 240 ° C in the
presence of a transesterification catalyst. In the
transesterification reaction, the DMT used as a raw ma-
terial exhibits a high volatility, so that it is pre-
ferred to use two or more reactors in combination, and
to control the reaction temperature appropriately.
It is preferred that the lower alcohol diester of
terephthalic acid and the TMG are charged into the re-
actor in a molar ratio (a lower alcohol diester of
terephthalic acid/TMG molar ratio) of from 1/1.3 to 1/4,
more advantageously from 1/1.5 to 1/2.5. When the
amount of TMG is too small so that the above-mentioned
ratio is larger than 1/1.3, the reaction time is likely
to become disadvantageously long. Also when the amount
of TMG is too large so that the above-mentioned ratio
is smaller than 1/4, the reaction time is likely to be-
come disadvantageously long, because it becomes neces-
sary to volatilize the excess TMG.
In the transesterification method, it is necessary
to use a transesterification catalyst. Preferred exam-
ples of transesterification catalysts include titanium
alkoxid.es, such as titanium tetrabutoxide and titanium
tetraisopropoxide; tin compounds, such as tin 2-
ethylhexanoate; cobalt acetate; calcium acetate; and
zinc acetate. Among these catalysts, titanium tetrabu-
toxide and tin 2-ethylhexanoate are preferred because
they function also as catalysts in the subsequent poly-
condensation reaction to produce the final resin. The
amount of transesterification catalyst is preferably in
the range of from 0.02 to 1 % by weight, more prefera-
bly from 0.05 to 0.5 % by weight, still more preferably
from 0.08 to 0.2 % by weight, based on the weight of
the diester of terephthalic acid.
Next, an explanation is made on the "direct es-
terification method". In the direct esterification
method, the BHPT is produced by subjecting terephthalic
acid and TMG to esterification reaction at 150 to
240 ° C.
It is preferred that the terephthalic acid and the
TMG are charged into a reactor in a molar ratio
(terephthalic acid/TMG molar ratio) of from 1/1.05 to
1/3, more preferably from 1/1.1 to 1/2. When the
amount of TMG is too small so that the above-mentioned
molar ratio is larger than 1/1.05, the reaction time is
likely to become disadvantageously long and the resul-
tant prepolymer is likely to be discolored. Also when
the amount of TMG is too large so that the above
-mentioned molar ratio is smaller than 1/3, the reac-
tion time is likely to become disadvantageously long
because it becomes necessary to volatilize the excess
TMG.
In the direct esterification method, free protons
derived from terephthalic acid function as a catalyst.
Therefore, in the direct esterification method, an es-
terif ication catalyst is not always necessary. However,
for improving the reaction rate, it is preferred to use
an esterification catalyst. Preferred examples of es-
terif ication catalysts include titanium alkoxides, such
as titanium tetrabutoxide and titanium tetraisopropox-
ide, and tin compounds, such as tin 2-ethylhexanoate.
It is preferred that the amount of esterification cata-
lyst used is from 0.02 to 1 % by weight, more prefera-
bly from 0.05 to 0.5 % by weight, still more preferably
from 0.08 to 0.2 % by weight, based on the weight of
terephthalic acid.
For advancing the esterification reaction smoothly,
it is preferred to add BHPT to a raw material mixture
at the start of the reaction in an amount of 5 to 80 %
by weight, based on the total weight of the raw mate-
rial mixture and the BHPT. When the production of BHPT
is performed in a batchwise manner, the esterification
reaction can be initiated by simultaneously charging
the terephthalic acid and the TMG (raw materials) into
a reactor. On the other hand, when the production of
BHPT is performed in a continuous manner, the esterifi-
cation reaction can be performed by continuously feed-
ing a predetermined amount of a mixture of terephthalic
acid and TMG into a reactor to perform a transesterifi-
cation reaction, while withdrawing a predetermined
amount of the reaction product (BHPT) from the reactor.
The BHPT obtained by any of the above-mentioned
methods is then subjected to polycondensation, thereby
obtaining the prepolymer used in the present invention.
The production of the prepolymer by polycondensa-
tion is performed by subjecting the BHPT to reaction at
a predetermined temperature under reduced pressure or
in an inert gas atmosphere, while withdrawing by-
produced TMG from the reaction system.
It is preferred that such polycondensation reac-
tion is performed at 230 to 280 °C. When the reaction
is performed at a temperature lower than 230oC, disad-
vantages are likely to occur that the formed prepolymer
gets solidified and that the reaction time becomes long.
On the other hand, when the reaction is performed at a
temperature which is higher than 280 °C, a disadvantage
is likely to occur that a vigorous heat decomposition
of the formed prepolymer occurs, and the resultant pre-
polymer cannot be used for producing a polymer having
excellent color. It is preferred that the polyconden-
sation reaction is performed at a temperature of from
232 to 275 °C, more advantageously from 235 to 270 °C.
As mentioned above, the polycondensation reaction
can be performed under reduced pressure or in an inert
gas atmosphere. When the reaction is performed under
reduced pressure, the pressure is appropriately con-
trolled, talcing into consideration the sublimation of
the BHPT and polycondensation product, and the reaction
rate. When the reaction is preformed in an inert gas
atmosphere, it is important that the inside of a reac-
tor used is always satisfactorily purged with inert gas
to withdraw the by-produced TMG efficiently from the
reaction system.
When the BHPT is subjected to polycondensation, it
is preferred to use a polycondensation catalyst. When a
polycondensation catalyst is not used, the reaction time
is likely to become disadvantageously long. Preferred
examples of polycondensation catalysts include titanium
alkoxides, such as titanium tetrabutoxide and titanium
tetraisopropoxide; titanium dioxide and a double salt of
titanium dioxide and silicon dioxide; antimony compounds.
such as diantimony trioxide and an antimony acetate; and
tin compounds, such as butyl stannate, butyltin tris(2-
ethylhexoate) and tin 2-ethylhexanoate. From the view-
point of improving the reaction rate and color of the
final resin, titanium tetrabutoxide and tin 2-
ethylhexanoate are especially preferred. The above-
mentioned catalysts can be used individually or in com-
bination. The amount of polycondensation catalyst used
is preferably from 0.001 to 1 % by weight, more prefera-
bly from 0.005 to 0.5 % by weight, still more preferably
from 0.01 to 0.2 % by weight, based on the weight of the
prepolymer. When a compound which functions as a poly-
condensation catalyst is used in the production process
of the BHPT, it is preferred that the total amount of
the compounds capable of functioning as a polycondensa-
tion catalyst is within the above-mentioned range.
Examples of devices for conducting such polycon-
densation reaction include a vertical agitation type
polymerizer, a horizontal agitation type polymerizer
equipped with one or two stirrers, a free-fall type
thin film polymerizer having trays therein, and a thin
film polymerizer in which the prepolymer is allowed to
fall on a plane surface of an angled plate. Needless
to say, these polymerizers can be used in combination.
When a polycondensation of BHPT is performed in a
batchwise manner, a single polymerizer can be employed
from the start of the polycondensation reaction through
the completion of the polycondensation reaction. Need-
less to say, two or more polymerizers can be used. On
the other hand, when a polycondensation of BHPT is per-
formed in a continuous manner, for effectively advanc-
ing the reaction, it is preferred to perform the reac-
tion of from the polycondensation to the formation of
the prepolymer in a stepwise manner, using two or more
different polymerizers, wherein the two or more poly-
merizers are operated under different temperature
-pressure conditions.
In the present invention, if desired, various ad-
ditives can be incorporated into the PTT resin by co-
polymerization or mixing. Examples of additives in-
clude a delustering agent, a thermal stabilizer, a
flame retardant, an antistatic agent, an anti-foaming
agent, an orthochromatic agent, an antioxidant, an ul-
traviolet absorber, a nucleating agent and a brightener.
These additives can be added at any time during the
production of the PTT resin.
In the present invention, from the viewpoint of
improving the whiteness and melt stability of the PTT
resin, and suppressing the formation of organic sub-
stances having a molecular weight of 300 or less, such
as acrolein and an allyl alcohol, it is preferred that
a stabilizer is added at an appropriate stage of the
production of the PTT resin, more advantageously before
the polycondensation of BHPT.
Preferred examples of such stabilizers include
pentavalent and/or trivalent phosphorus compounds and
hindered phenol compounds.
Examples of pentavalent and/or trivalent phospho-
rus compounds include trimethyl phosphate, triethyl
phosphate, tributyl phosphate, triphenyl phosphate,
trimethyl phosphite, triethyl phosphite, tributyl
phosphite, triphenyl phosphite, phosphoric acid and
phosphorous acid. Among the above-mentioned phosphorus
compounds, trimethyl phosphite is especially preferred.
It is preferred that the amount of phosphorus compound
added is in the range of from 2 to 250 ppm by weight,
more advantageously from 5 to 150 ppm by weight, still
more advantageously from 10 to 100 ppm by weight, in
terms of the weight of phosphorus atom contained in the
PTT.
The hindered phenol compound is a phenol deriva-
tive which has a substituent exhibiting a steric hin-
drance at a position adjacent to the phenolic hydroxyl
group, and has at least one ester bond in its molecule.
Examples of hindered phenol compounds include pen-
taerythritol-tetrakis[3-(3,5-di-tert-butyl-4-
hydroxyphenyl)propionate] , 1,1,3-tris(2-methyl-4 -
hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-
2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene,
3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)-
propionyloxy]-1,1-dimethylethy1}-2,4,8,10-
tetraoxaspiro[5,5 Jundecane, l,3,5-tris(4-tert-butyl-3 -
hydroxy-2,6-dimethylbenzene)isophthalic acid, triethyl
glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)-
propionate], 1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4-
hydroxyphenyl)propionate], 2,2-thio-diethylene-bis[3-
(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and oc-
tadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-
propionate].
Among the above-exemplified hindered phenol com-
pounds , pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-
4-hydroxyphenyl)propionate] is preferred.
It is preferred that the amount of hindered phenol
compound added is in the range of from 0.001 to 1 % by
weight, more advantageously from 0.005 to 0.5 % by
weight, still more advantageously from 0.01 to 0.1 % by
weight, based on the weight of the PTT resin. Needless
to say, the above-mentioned stabilizers can be used in
combination.
Next, preferred examples of the polymerizer used
in the method of the present invention are described
below, referring to the drawings.
Fig. 1 shows an explanatory diagrammatic view of a
specific example of a polymerizer used in the method of
the present invention. In Fig. 1, trimethylene
terephthalate prepolymer A is fed through inlet 2 into
polymerizer 10 by means of transferring pump 1. Then,
prepolymer A is introduced through perforated plate 3
into the interior (polymerization reaction zone) of po-
lymerizer 10, and is allowed to fall along and in con-
tact with guides 5. The pressure in the interior (po-
lymerization reaction zone) of polymerizer 10 is con-
trolled so as to maintain a predetermined reduced pres-
sure. If desired, inert gas E, such as nitrogen, can
be introduced into the polymerizer through inlet 6 for
a gas. TMG (which is distilled from the prepolymer)
and inert gas E are discharged as exhaust gas D from
vent 7. The resultant PTT resin B is withdrawn from
the polymerizer by means of withdrawal pump 8 through
outlet 9. Polymerizer 10 is heated by means of a
heater or a jacket so as to maintain the temperature
inside the polymerizer at a desired level.
Fig. 2 shows explanatory diagrammatic views of
specific examples of an inert gas absorption device and
a polymerizer, which can be used in the present inven-
tion when the inert gas is introduced to the polymeri-
zation reaction zone in such a form as absorbed or con-
tained in the PTT prepolymer, and the inert gas is
caused to be released from the prepolymer in the polym-
erization reaction zone under reduced pressure. In Fig.
2, PTT prepolymer A is continuously fed through inlet N3
into the inert gas absorption device Nl by means of
transferring pump N2 . Then, the prepolymer is continu-
ously fed through perforated plate 4 into the interior
of the inert gas absorption device, into which inert
gas E is introduced through inlet N6 for inert gas. In
the inert gas absorption device, the prepolymer is al-
lowed to fall along and in contact with guides 5. The
resultant prepolymer (which contains and/or has ab-
sorbed therein the inert gas) is fed through inlet 2
into polymerizer 10 by means of transferring pump 7.
The prepolymer is then continuously fed through perfo-
rated plate 4 into the interior (polymerization reac-
tion zone) of polymerizer 10, and is allowed to fall
along and in contact with guides 5.
The pressure in the interior (polymerization reac-
tion zone) of polymerizer 10 is controlled so as to
maintain a predetermined reduced pressure. The inert
gas which is absorbed and/or contained in prepolymer A
is released from the prepolymer in the polymerization
reaction zone of the polymerizer. TMG (which is dis-
tilled from the prepolymer) and the inert gas (which is
introduced into the polymerizer) are discharged as ex-
haust gas D through vent 7. The resultant PTT resin B
is continuously withdrawn from outlet 9 by means of
withdrawal pump 8. Inert gas absorption device Nl and
polymerizer 10 are heated by means of a heater or a
jacket so as to maintain the temperature inside the po-
lymerizer at a desired level.
In each of the above-mentioned methods, the PTT
resin (obtained by a polymerization performed by allow-
ing the prepolymer to fall along and in contact with
the guide) which is accumulated at the bottom portion
of the polymerizer is withdrawn from the outlet by
means of a withdrawal pump. It is preferred that the
withdrawal of the PTT resin from the polymerizer is
performed in a manner such that the amount of the PTT
resin accumulated at the bottom portion of the polymer-
izer becomes as small as possible and constant. When
the withdrawal of the PTT resin is performed in such a
manner, it becomes easy to prevent the PTT resin from
suffering disadvantages, such as discoloration (caused
by heat decomposition), lowering of polymerization de-
gree, and fluctuation of the quality. The amount of
the PTT resin accumulated at the bottom portion of the
polymerizer can be controlled by means of transferring
pump 1 and withdrawal pump 8, while observing the
amount of the PTT resin accumulated at the bottom por-
tion of the polymerizer.
The polymerizer used in the present invention can
be equipped with a stirrer at the bottom portion
thereof, but such a stirrer is not necessary. Thus, in
the method of the present invention, it is possible to
perform a polymerization reaction using a polymerizer
having no rotary driving part, so that the polymerizer
can be tightly sealed even when a polymerization is
performed under high vacuum conditions. The sealabil-
ity of the rotary driving part of the withdrawal pump
is improved due to the liquid head, as compared to that
of a polymerizer having a rotary driving part.
The method of the present invention can be con-
ducted using either a single polymerizer or a plurality
of polymerizers. Further, it is also possible to use a
multi-chamber polymerizer prepared by dividing an inner
space of a single polymerizer into a plurality of hori-
zontally adjacent chambers or a plurality of vertically
adjacent chambers.
In the present invention, it is preferred to in-
crease, in advance, the polymerization degree of the
prepolymer (which is to be subjected to the above-
mentioned guide-wetting fall polymerization process) to
some extent by at least one polymerization method se-
lected from the following methods (a) to (d):
(a) a polymerization method using a vertical agi-
tation type polymerizer;
(b) a polymerization method using a horizontal
agitation type polymerizer;
(c) a polymerization method using a free-fall po-
lymerizer having a perforated plate,- and
(d) a polymerization method using a thin film
type polymerizer.
Examples of horizontal agitation type polymeriz-
ers include a screw-type polymerizer (such as a single-
screw type polymerizer or a twin-screw type polymer-
izer) and an independent agitation element type poly-
merizer, which are described in "Hanno Kougaku Kenkyu-
kai kenkyu Repoto: Riakutibupurosessingu Part 2 (Re-
search Group on Reaction Engineering, Research Report:
Reactive Processing Part 2)", Chapter 4, edited by The
Society of Polymer Science, Japan, 1992.
With respect to the free-fall polymerizer having a
perforated plate, reference can be made to, for example,
U.S. Patent No. 5,596,067. When the free-fall polymer-
izer is used, a polymerization is performed by allowing
the prepolymer to fall freely from the holes of the
perforated plate provided in the polymerizer. More
specifically, a polytrimethylene terephthalate prepoly-
mer in a molten form is allowed to fall freely from the
holes of the perforated plate, thereby improving the
polymerization degree of the prepolyraer. Herein, the
expression "fall freely" means that the prepolymer is
allowed to fall without contacting any materials (such
as a guide and an inner wall of the polymerizer) which
obstruct the fall of the prepolymer. The prepolymer is
allowed to fall freely in the form of a film, a fiber,
a droplet, a fog or the like. TMG which is produced
during the polycondensation reaction is withdrawn from
the reaction system during the fall of the prepolymer.
In the above-mentioned method using a free-fall
polymerizer, there is no particular limitation with re-
spect to the shape of the holes of the perforated plate,
and generally, the shape can be a circle, an ellipse, a
triangle, a slit, a polygon, a star or the like. The
cross-sectional area of each of the holes is generally
in the range of from 0.01 to 100 cm , preferably from
0.05 to 10 cm , more preferably from 0.1 to 5 cm .
Further, the holes can have a nozzle or a short guide
attached thereto. However, it is necessary that the
nozzle or the short guide is attached to the holes so
that the prepolymer can fall freely after having passed
through the nozzle or after having fallen along and in
contact with the guide. The distance between mutually
adjacent holes of the perforated plate is generally
from 1 to 500 mm, preferably from 5 to 100 mm, as meas-
ured between the respective centers of the mutually ad-
jacent holes. With respect to the distance over which
the prepolymer (having passed through the holes of the
perforated plate) falls freely, the distance is pref-
erably from 0.3 to 50 m, more preferably from 0.5 to 20
m. The amount of prepolymer which is caused to pass
through the holes varies depending on the molecular
weight of the prepolymer, but is generally in the range
of from 10"4 to 104 liters/hr, preferably from 10"2 to
102 liters/hr, more preferably from 0.1 to 50 liters/hr,
per hole of the perforated plate. There is no particu-
lar limitation with respect to the time for allowing
the prepolymer to fall freely from the perforated plate,
but in general, it is in the range of from 0.01 second
to 1 hour. The thus obtained prepolymer may be with-
drawn from the polymerizer. Alternatively, the ob-
tained prepolymer may be recycled to the free-fall po-
lymerizer, and subjected to further free-fall polymeri-
zation. The recycling of the obtained prepolymer to
the polymerizer has the following advantage. When the
free-fall polymerization is performed while recycling
the obtained prepolymer, the area of the prepolymer
surface renewed per unit time is large, as compared to
that in the case where the obtained prepolymer is not
recycled. Therefore, by recycling the obtained polymer
to the polymerizer, it becomes easy to achieve a de-
sired degree of polymerization.
Further examples of vertical and horizontal agi-
tation type polymerizers include those which are de-
scribed in "Kagaku Souchi Binran (Handbook of Chemical
Apparatuses)", Chapter 11, edited by The Society of
Chemical Engineers, Japan, 1989. There is no particu-
lar limitation with respect to the shape of the vessel,
and in general, the shape may be a vertical or horizon-
tal cylinder. Further, there is no particular limita-
tion with respect to the shape of the agitation element,
and the shape of agitation element can be a paddle, an
anchor, a turbine, a screw, a ribbon, double wings or
the like.
Examples of thin film type polymerizers include a
wall-wetting fall polymerizer, and polymerizers
equipped with a centrifugal thin film type heat ex-
changer, a liquid film scraping type heat exchanger or
the like. As an example of the above-mentioned wall
-wetting fall polymerizer, there can be mentioned a po-
lymerizer described in the above-mentioned "Kagaku
Souchi Binran (Handbook of Chemical Apparatuses)",
Chapter 11, p. 461, published by The Society of Chemi-
cal Engineers, Japan, 1989. The thin film type poly-
merizer may have a multi-tubular structure. Further,
the prepolymer obtained by the wall-wetting fall may be
recycled to the polymerizer, and subjected to further
wall-wetting fall polymerization. Examples of liquid
film scraping type heat exchangers and centrifugal thin
film type heat exchangers include those which are de-
scribed in "Netsukoukanki Sekkei Handobukku (Handbook
for designing a heat exchanger)". Chapters 21-22, pub-
lished by Kougakutosho Ltd., Japan, 1974.
The production of a prepolymer from the raw mate-
rials can be performed in either a batchwise manner or
a continuous manner. When the prepolymer is produced
in a batchwise manner, all of the raw materials or the
whole of a reaction product (i.e., a prepolymer having
a molecular weight lower than a desired level) are or
is charged into a reaction vessel and reacted for a
predetermined period of time, and then, the whole of
the resultant reaction product is transferred to an-
other reaction vessel. On the other hand, when the
prepolymer is produced in a continuous manner, raw ma-
terials or a reaction product (i.e., a prepolymer hav-
ing a molecular weight lower than a desired level) are
or is continuously fed into a reaction vessel, while
continuously withdrawing the resultant reaction product
from the reaction vessel. For obtaining a large amount
of a polytrimethylene terephthalate resin having a uni-
form quality, it is preferred that the production of
the prepolymer is performed in a continuous manner.
With respect to the material of the polymerizer
used in the present invention, there is no particular
limitation. In general, the material is selected from
the group consisting of, for example, stainless steel,
nickel and glass lining.
Next, preferred examples of combinations of poly-
merizers which are used for producing a PTT resin from
the raw materials are described below, referring to the
drawings. However, the combinations of polymerizers
usable in the present invention should not be limited
to those examples.
Fig. 3 shows an example of a system used for pro-
ducing the PTT resin from terephthalic acid and TMG as
raw materials, which system comprises a combination of
vertical agitation type polymerizers and a polymerizer
used for performing the guide-wetting fall process. In
Fig. 3, mixture C containing raw materials (terephthalic
acid and TMG) and a catalyst is charged into esterifica-
tion reaction vessel 11, and subjected to an esterifica-
tion reaction for a predetermined period of time, while
stirring by means of agitation element 12, thereby ob-
taining bis(3-hydroxylpropyl)-terephthalate (BHPT). The
atmosphere inside the reaction vessel is an atmosphere
of inert gas, such as nitrogen gas, and/or an atmosphere
containing water (steam) and/or TMG which are distilled
from a reaction mixture in the reaction vessel. In gen-
eral, the pressure inside the reaction vessel is con-
trolled so as to be around atmospheric pressure. The
water and TMG (which are distilled from the reaction
mixture) and/or excess nitrogen gas are discharged from
vent 13 as exhaust gas D. The BHPT obtained in esteri-
fication reaction vessel 11 is transferred by means of
transferring pump 14 to first vertical agitation type
polymerizer 15, where the BHPT is subjected to polymeri-
zation for a predetermined period of time, while stir-
ring by means of agitation element 16, thereby obtaining
a low molecular weight prepolymer A. The inside of the
polymerizer is under reduced pressure, or inert gas
(such as nitrogen gas) is flowed through the inside of
the polymerizer. The water and TMG (which are distilled
from polymer A) and/or excess nitrogen gas is discharged
from vent 17 as exhaust gas D.
The low molecular weight prepolymer A obtained in
first vertical agitation type polymerizer 15 is trans-
ferred by means of transferring pump 18 to second ver-
tical agitation type polymerizer 19, where the prepoly-
mer A is subjected to polymerization for a predeter-
mined period of time, while stirring by means of agita-
tion element 20, thereby obtaining a prepolymer. The
inside of the polymerizer is under reduced pressure, or
inert gas (such as nitrogen gas) is flowed through the
inside of the polymerizer. The water and TMG (which
are distilled from the prepolymer A) and/or excess ni-
trogen gas is discharged from vent 21 as exhaust gas D.
The prepolymer A having an increased molecular weight,
which is obtained in second vertical agitation type po-
lymerizer 19, is transferred and continuously fed
through inlet 2 into polymerizer 10 by means of trans-
ferring pump 1. In polymerizer 10, the prepolymer A is
caused to pass through perforated plate 3, and is in-
troduced into the interior (polymerization reaction
zone) of the polymerizer, where the prepolymer A is al-
lowed to fall along and in contact with guides 5. The
pressure in the polymerization reaction zone is con-
trolled so as to be a predetermined reduced pressure.
TMG (distilled from the prepolymer A) and inert gas E
(which is optionally introduced into the polymerizer
through inlet 6 for a gas) if any, are discharged from
vent 7. The obtained PTT resin B is continuously with-
drawn from outlet 9 by means of withdrawal pump 8.
Esterification reaction vessel 11, first vertical
agitation type polymerizer 15, second vertical agita-
tion type polymerizer 19, polymerizer 10, conduits and
transferring pumps are heated by means of a heater or a
jacket so as to maintain the temperatures of the reac-
tion vessel, polymerizers, conduits and pumps at de-
sired levels.
Fig. 4 shows an example of a system used for pro-
ducing the PTT resin from terephthalic acid and TMG as
raw materials, which system comprises a combination of
a vertical agitation type polymerizer, a horizontal
agitation type polymerizer and a polymerizer for per-
forming the guide-wetting fall process. In Fig. 4,
mixture C of raw materials (terephthalic acid and TMG)
and a catalyst is charged into esterification reaction
vessel 11, and subjected to an esterification reaction
for a predetermined period of time, while stirring by
means of agitation element 12, thereby obtaining BHPT.
The atmosphere inside the reaction vessel is an atmos-
phere of inert gas, such as nitrogen gas, and/or an at-
mosphere containing water (steam) and/or TMG which are
distilled from a reaction mixture in the reaction ves-
sel. In general, the pressure inside the reaction ves-
sel is controlled to approximately atmospheric pressure.
The water and TMG (which are distilled from the reac-
tion mixture) and/or excess nitrogen gas are discharged
from vent 13 as exhaust gas D. The BHPT obtained in
esterification reaction vessel 11 is transferred by
means of transferring pump 14 to first vertical agita-
tion type polymerizer 15, where the BHPT is subjected
to polymerization for a predetermined period of time,
while stirring by means of agitation element 16,
thereby obtaining a low molecular weight prepolymer A.
The inside of the polymerizer is under reduced pressure,
or inert gas (such as nitrogen gas) is flowed through
the inside of the polymerizer. The water and TMG
(which are distilled from polymer A) and/or excess ni-
trogen gas is discharged from vent 17 as exhaust gas D.
The low molecular weight prepolymer A obtained in
first vertical agitation type polymerizer 15 is trans-
ferred by means of transferring pump 20 to horizontal
agitation type polymerizer 22, where the prepolymer A
is subjected to polymerization for a predetermined pe-
riod, while stirring by means of agitation element 23,
thereby obtaining a prepolymer A having an increased
molecular weight. The inside of the polymerizer is un-
der reduced pressure, or inert gas (such as nitrogen
gas) is flowed through the inside of the polymerizer.
The water and TMG (which are distilled from polymer A)
and/or excess nitrogen gas is discharged from vent 24
as exhaust gas D. The prepolyraer A having an increased
molecular weight, which is obtained in horizontal agi-
tation type polymerizer 22, is transferred and continu-
ously fed through inlet 2 into polymerizer 10 by means
of transferring pump 1. In polymerizer 10, the pre-
polymer A is caused to pass through perforated plate 3,
and is introduced into the interior (polymerization re-
action zone) of the polymerizer, where the prepolymer A
is allowed to fall along and in contact with guides 5.
The pressure in the polymerization reaction zone is
controlled to a predetermined reduced pressure. TMG
(distilled from the prepolymer A) and inert gas E
(which is optionally introduced into the polymerizer
through inlet 6 for a gas) if any, are discharged from
vent 7. The obtained PTT resin B is continuously with-
drawn from outlet 9 by means of withdrawal pump 8.
Esterification reaction vessel 11, vertical agi-
tation type polymerizer 15, horizontal agitation type
polymerizer 22, polymerizer 10, conduits and transfer-
ring pumps are heated by means of a heater or a jacket
so as to maintain the temperatures of the reaction ves-
sel, polymerizers, conduits and pumps at desired levels.
Each of Figs. 5 and 6 shows an example of a sys-
tem used for producing the PTT resin from DMT and TMG
as raw materials . In each of Figs . 5 and 6 , mixture C
of raw materials and a catalyst is charged into first
transesterification reaction vessel 25, and the resul-
tant reaction product is transferred to second trans-
esterif ication reaction vessel 29. In each of first
transesterification reaction vessel 25 and second
transesterification reaction vessel 29, mixture C of
raw materials is subjected to a transesterification re-
action for a predetermined period of time, while stir-
ring by means of agitation element (26 or 30), thereby
obtaining BHPT. The atmosphere inside the reaction
vessel is an atmosphere of inert gas, such as nitrogen
gas, and/or an atmosphere containing methanol and/or
TMG which are distilled from a reaction mixture in the
reaction vessel. In general, the pressure inside the
reaction vessel is controlled to approximately atmos-
pheric pressure. The vent of each of the reaction ves-
sels is connected to a fractionating column. TMG dis-
tilled from the fractionating column is recycled to the
reaction vessel. Methanol and excessive nitrogen are
discharged from the fractionating column. The obtained
BHPT is subjected to polycondensation in the same man-
ner as mentioned above in connection with the systems
shown in Figs. 3 and 4, thereby obtaining prepolymer A
and then, PTT resin B.
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinbelow, the present invention will be de-
scribed in more detail with reference to the following
Examples and Comparative Examples, which should not be
construed as limiting the scope of the present inven-
tion .
In the following Examples and Comparative Examples,
various measurements and analyses were conducted by the
following methods.
(1) Intrinsic viscosity [?]
Intrinsic viscosity [?] of a polymer (i.e., a pre-
polymer or a final polytrimethylene terephthalate
resin) was measured by means of an Oswald viscometer.
Specifically, with respect to each of o-chlorophenol
solutions of a polymer, which have different concentra-
tions [C] (g/100 ml) of the resin, the relative viscos-
ity [?sp] was measured at 35 °C. The obtained {?sp/C)
values were plotted against the concentrations of the
resin, and the resultant gradient is extrapolated into
the zero (0) concentration to thereby obtain an intrin-
sic viscosity [?] of the polymer. That is, the intrin-
sic viscosity [?] of the polymer was calculated by the
following formula:
102
[?] = lim (T]sp/C)
.
(2) Crystalline melting point
The crystalline melting point of a prepolymer was
measured by means of a differential scanning calorime-
ter (trade name-. Pyris 1; manufactured and sold by
Perkin Elmer, Inc., U.S.A.) under the following condi-
tions :
Measuring temperature: 0 to 280 ° C
Rate of temperature elevation: 10 • C/min
Specifically, a temperature at which an endother-
mic peak ascribed to the melting of a crystal is ob-
served in the obtained differential scanning calo-
rimetry (DSC) chart was defined as the crystalline
melting point of the prepolymer, wherein the determina-
tion of the peak was conducted using an analytic soft-
ware attached to the calorimeter.
(3) Terminal carboxyl group content
1 g of a polymer (i.e., a prepolymer or a final
polytrimethylene terephthalate resin) was dissolved in
25 ml of benzyl alcohol, followed by addition of 25 ml
of chloroform, thereby obtaining a mixture. The ob-
talned mixture was subjected to a titration with a 1/50
N solution of potassium hydroxide in benzyl alcohol.
From the obtained titration value VA (ml) and a blank
test value Vo (ml) which is obtained by a titration
conducted in the absence of the polymer, the terminal
carboxyl group content was calculated by the following
formula:
Terminal carboxyl group content (meq/kg)
= (VA - Vo) x 20 .
(4) Total terminal group content
The total amount of terminal groups per kg of a
sample is defined as the total terminal group content.
Specifically, the total terminal group content (meq/kg)
is calculated from the intrinsic viscosity [?] by the
following formula:
Total terminal group content (meq/kg)
= 1,000/(polymerization degree x 206) x 2 x 1,000
wherein:
the polymerization degree
= intrinsic viscosity [?] x 144.6 - 26.2.
(5) Molecular weight distribution
The ratio of the weight average molecular weight
(Mw) to the number average molecular weight (Mn) (Mw/Mn
ratio) was used to evaluate the molecular weight dis-
tribution of a polytrimethylene terephthalate resin.
The Mw and Mn of a polytrimethylene terephthalate resin
were determined by gel permeation chromatography (GPC).
Specifically, the GPC was conducted under the following
conditions:
Apparatus: chromatograph model HLC-8120 (manufac-
tured and sold by Tosoh Corporation, Japan);
Columns: HFIP804-803 (30 cm) (manufactured and
sold by Showa Denko K.K., Japan) (x 2);
Carrier: hexafluoroisopropanol;
Measurement temperature: 40 °C; and
Flow rate : 0.5 ml/min.
A calibration curve used in the determination of the Mn
and Mw was obtained by using standard polymethyl
methacrylate (PMMA) samples (manufactured and sold by
Polymer Laboratories Ltd., U.K.). The molecular
weights of the PMMA samples used were 620, 1,680, 3,805,
7,611, 13,934, 24,280, 62,591 and 186,000, respectively.
(6) Color (L-value and b*-value)
A pellet of a polytrimethylene terephthalate resin
(PTT) was heated at 100 °C for 10 minutes to partially
crystallize the pellet. The color (in terms of L-value
and b*-value thereof) of the obtained partially crys-
tallized pellet was measured by means of a color meas-
uring computer (manufactured and sold by SUGA TEST IN-
STRUMENTS Co., Ltd., Japan).
Separately from the above, another pellet of PTT
resin was heated at 180 °C for 24 hours, and then, the
color thereof was measured in the same manner as men-
tioned above, except that the heating at 100 °C for
partially crystallizing the PTT resin was not conducted
since the pellet was already crystallized by the above
-mentioned heating at 180 °C. The thus obtained
L-value and b*-value of the PTT resin were used as a
yardstick of the discoloration of the PTT resin caused
by the heating.
(7) Pellet size
Approximately 2 g of pellets were used as sample
pellets . The total weight of the sample pellets was
accurately weighed, and the number of sample pellets
was counted. From the total weight and the number of
the sample pellets, the average weight of the pellets
was calculated.
(8) Polymer powder
The amount of polymer powder attached to the sur-
face of pellets was measured as follows.
1. 1 kg of pellets were placed In a beaker filled
with water.
2. The pellets in the beaker were stirred for 5
minutes to wash away the polymer powder from
the surface of the pellets.
3. The contents of the beaker were filtered
through a 30-mesh filter. Then, the pellets on
the filter were repeatedly washed with water so
that broken pieces of pellets and/or polymer
powder would not remain on the pellets.
4. The resultant filtrate obtained in step 3 above
was filtered again through a 300-mesh filter.
The residue on the filter was dried at 80 "C
under reduced pressure, namely, under a pres-
sure of 1 kPa. The dried residue was weighed,
and the measured weight was defined as the
weight of the polymer powder.
(9) Crystallinity
The density of the pellets was measured in accor-
dance with JIS-L-1013, in which the density of
the pellets was measured by gradient density tube
method in which a gradient density tube prepared using
tetrachlorocarbon and n-heptanone was used. The meas-
urement was conducted with respect to 10 pellets, and
the average of the measured values was defined as the
density of the pellets. Using the obtained value (ps)
of the density, the crystallinity of the pellets was
calculated by the following formula:
Xc (%) = {?c x (?s - ?a)}/(?s x (?c - ?a)> x
100
wherein pa is 1.300 g/cm3 which is an amor-
phous density of trimethylene terephthalate
homopolymer, pc is 1.431 g/cm3 which is a
crystal density of trimethylene terephtha-
late homopolymer, and ps represents a den-
sity (g/cm3) of the pellets.
Example 1
Using the device as shown in Fig. 1, production of
polytrimethylene terephthalate resin B was conducted as
follows. A polytrimethylene terephthalate (PTT) pre-
polymer A having an intrinsic viscosity [?] of 0.5 dl/g,
a terminal carboxyl group ratio of 7 % and a crystal-
line melting point of 230 ° C was fed through, prepolymer
feeding inlet 2 into polymerizer 10 by means of trans-
ferring pump 1 . In polymerizer 10 , PTT prepolymer A
was caused to pass through the holes of perforated
plate 3 in a molten form at 260 °C (temperature of the
molten polymer) and at a rate of 10 g/min per hole, and
then, was allowed to fall along and in contact with
guides 5 at an atmospheric temperature of 260 oC, which
is the same as the temperature of the molten prepolymer
(having passed through the holes of perforated plate 3),
under reduced pressure, namely, under a pressure of 10
Pa, to thereby perform a polymerization to obtain PTT
resin B. The obtained PTT resin B was withdrawn from
outlet 9 by means of withdrawal pump 8. The perforated
plate had a thickness of 50 mm and nine holes, each
having a diameter of 1 mm, in which the holes of the
perforated plate are arranged such that a checkered
pattern is formed when lines connecting the holes are
drawn on the surface of the perforated plate. The
guide was a wire made of stainless steel, which wire
had a circular cross- section, and had a diameter of 3
mm and a length of 5 m. Guides 5 were attached to per-
forated plate 4 so that each hole of perforated plate 5
had one guide 5 attached thereto. The withdrawal pump
was operated while observing the polymer inside the po-
lymerizer through observing window 4, so that almost no
polymer was accumulated at the bottom of the polymer-
izer. (The above-mentioned prepolymer A contained ti-
tanium tetrabutoxide (polymerization catalyst) and
trimethyl phosphate (stabilizer) in amounts of 0.1 % by
weight and 100 ppm by weight (in terms of the weight of
phosphorus), respectively, both of which are based on
the weight of the prepolymer.) The results are shown
in Table 1.
In the above-mentioned polymerization, the reten-
tion time was 60 minutes. The retention time herein is
a value calculated by dividing the total amount of the
prepolymer and polymer inside the polymerizer by the
feeding rate of the prepolymer.
With respect to the staining of the lower surface
of the perforated plate, which was caused by the foam-
ing of the prepolymer immediately below the holes of
the perforated plate, the level of staining was low.
The obtained PTT resin had a high molecular weight, a
narrow molecular weight distribution, a low terminal
carboxyl group content, and excellent color. Further,
the degree of discoloration of the obtained PTT resin
occurring by heating was very small.
The obtained PTT resin was solidified in cool wa-
ter having a temperature of 5 °C, and then, cut into
pellets, each having a weight of 20 rag. The amount of
polymer powder (which had adhered to the pellets) was
as low as 0.01 % by weight, and the pellets had a crys-
tallinity of 5 %. Therefore, the obtained pellets were
not easily broken and easy to handle.
Examples 2 to 4
In each of Examples 2 to 4, polymerization was
performed in substantially the same manner as in Exam-
ple 1, except that polymerization was performed under
the conditions indicated in Table 1. The results are
shown in Table 1. In each of Examples 2 to 4, with re-
spect to the staining of the lower surface of the per-
forated plate, which was caused by the foaming of the
prepolymer immediately below the holes of the perfo-
rated plate, the level of staining was low. The ob-
tained PTT resins had a high molecular weight, a narrow
molecular weight distribution, a low terminal carboxyl
group content, and excellent color. Further, with re-
spect to each of the obtained PTT resins, the degree of
discoloration occurring by heating was very small.
Comparative Examples 1 to 4
In each of Comparative Examples 1 to 4, polymeri-
zation was performed in substantially the same manner
as in Example 1, except that the polymerization was
performed under the conditions indicated in Table 1 .
The results are shown in Table 1.
In Comparative Example 1, the temperature of the
molten preploymer introduced into the polymerization
reaction zone was too high, so that a vigorous foaming
of the prepolymer occurred just below the holes of the
perforated plate, thereby markedly staining the lower
surface of the perforated plate. The obtained PTT
resin was discolored to assume a yellow color and the
color of the PTT resin thereof was non-uniform. Fur-
ther, the PTT resin suffered severe discoloration by
heating.
In Comparative Example 2, the temperature of the
molten preploymer introduced into the polymerization
reaction zone was too low, so that the prepolymer was
solidified, and hence, the prepolymer could not pass
through the holes of the perforated plate.
In Comparative Example 3, the prepolymer had an
intrinsic viscosity [?] of 0.18 dl/g, which was too low,
so that a vigorous foaming of the prepolymer occurred
just below the holes of the perforated plate, thereby
markedly staining the lower surface of the perforated
plate, and the inner wall of the polymerizer. The ob-
tained PTT resin contained a large amount of black im-
purities (heat deterioration products). Further, the
obtained PTT had a low molecular weight.
In Comparative Example 4. polymerization in the
polymerizer was performed under atmospheric pressure.
As a result, it was found that the polymerization de-
gree of the obtained PTT was not increased, but rather
lowered by the heat decomposition.
Example 5
A polymerization was performed in substantially
the same manner as in Example 1, except that the guide
was changed to a jungle gym-like body, in which wires
(each having a diameter of 3 mm) were three
-dimensionally connected with one another at intervals
of 30 mm as viewed in the vertical direction and at in-
tervals of 50 mm as viewed in the horizontal direction.
The upper end portions of the wires extending in the
vertical direction were attached to the holes of the
perforated plate. The results are shown in Table 1.
With respect to the staining of the lower surface of
the perforated plate, which was caused by the foaming
of the prepolymer immediately below the holes of the
perforated plate, the level of staining was low.
The obtained PTT resin had a high molecular weight
a narrow molecular weight distribution, and excellent
color. Further, the degree of discoloration of the ob-
tained PTT resin occurred even by heating.
Example 6
Polymerization was performed in substantially the
same manner as in Example 1, except that the guide was
changed to a wire mesh, in which wires (each having a
diameter of 3 mm) were two-dimensionally connected with
one another at intervals of 30 mm as viewed in the ver-
tical direction and at intervals of 50 mm as viewed in
the horizontal direction. The upper end portions of
the wires extending in the vertical direction were at-
tached to the holes of the perforated plate. The re-
sults are shown in Table 1.
With respect to the staining of the lower surface
of the perforated plate, which was caused by the foam-
ing of the prepolymer immediately below the holes of
the perforated plate, the level of staining was low.
The obtained PTT resin had a high molecular weight,
a narrow molecular weight distribution, a low terminal
carboxyl group content, and excellent color. Further,
the degree of discoloration of the obtained PTT resin
occurring by heating was very small.
Example 7
Using the production system as shown in Fig. 3,
130 kg of a polytrimethylene terephthalate (PTT) resin
was continuously produced per day, in which
terephthalic acid and TMG were used as raw materials.
With respect to the apparatuses used in the above-
mentioned production system, each of esterification re-
action vessel 11, first vertical agitation type poly-
raerizer 15 and second vertical agitation type polymer-
izer 19 was a vertical agitation type polymerizer
equipped with a stirrer having paddle-shaped agitation
blades, and polymerizer 10 was the same as used in Ex-
ample 5 .
Specifically, production of the PTT resin was per-
formed as follows. Terephthalic acid and TMG were
mixed together (terephthalic acid/TMG molar ratio =
1/1.5), followed by addition of 0.1 % by weight of ti-
tanium tetrabutoxide, based on the weight of
terephthalic acid, thereby obtaining a mixture (in the
form of a slurry). The obtained mixture was continu-
ously charged into esterification reaction vessel 11,
and a polymerization was performed in substantially the
same manner as in Example 1, except that the polymeri-
zation was performed under the conditions indicated in
Tables 1 and 2, thereby obtaining a polytrimethylene
terephthalate (PTT) resin. During the polymerization.
trimethyl phosphate (stabilizer) was continuously added
to first vertical agitation type polymerizer 15 in an
amount of 20 ppm by weight, based on the weight of the
polymer. The results are shown in Table 1.
The prepolymer which was fed into the final poly-
merizer 10 satisfied the requirements of the present
invention, and the obtained PTT resin had a high mo-
lecular weight, a narrow molecular weight distribution,
a low terminal carboxyl group content, and excellent
color. Further, the degree of discoloration of the ob-
tained resin occurring by heating was very small.
Example 8
Using the production system as shown in Fig. 4,
130 kg of a polytrimethylene terephthalate (PTT) resin
was continuously produced per day, wherein terephthalic
acid and TMG were used as raw materials. With respect
to the apparatuses used in the above-mentioned produc-
tion system, each of esterification reaction vessel 11
and first vertical agitation type polymerizer 15 was a
vertical agitation type polymerizer equipped with a
stirrer having paddle-shaped agitation blades; horizon-
tal agitation type polymerizer 22 was equipped with a
uniaxial stirrer having disc-shaped agitation blades;
and polymerizer 10 was the same as used in Example 5.
Specifically, production of the PTT resin was per-
formed as follows. Terephthalic acid and TMG were
mixed together (terephthalic acid/TMG molar ratio =
1/1.5), followed by addition of 0.1 % by weight of ti-
tanium tetrabutoxide, based on the weight of
terephthalic acid, thereby obtaining mixture C (in the
form of a slurry). The obtained mixture C was continu-
ously charged into esterification reaction vessel 11,
and polymerization was performed in substantially the
same manner as in Example 1, except that the polymeri-
zation was performed under the conditions indicated in
Tables 1 and 3, thereby obtaining a polytrimethylene
terephthalate (PTT) resin. During the polymerization,
trimethyl phosphate (stabilizer) was continuously added
to first vertical agitation type polymerizer 15 in an
amount of 20 ppm by weight, based on the weight of the
polymer. The results are shown in Table 1.
The prepolymer which was fed into the final poly-
merizer 10 satisfied the requirements of the present
invention, and the obtained PTT resin had a high mo-
lecular weight, a narrow molecular weight distribution,
a low terminal carboxyl group content, and excellent
color. Further, the degree of discoloration of the ob-
tained PTT resin occurring by heating was very small.
Example 9
Using the production system as shown in Fig. 5,
130 kg of polytrimethylene terephthalate (PTT) resin
was continuously produced per day, wherein DMT and TMG
were used as raw materials . With respect to the appa-
ratuses used in the above-mentioned production system,
each of first transesterification reaction vessel 25
and second transesterification reaction vessel 29 was a
vertical agitation type polymerizer equipped with a
stirrer having turbine blades (26 or 30); each of first
vertical agitation type polymerizer 15 and second ver-
tical agitation type polymerizer 19 was equipped with a
stirrer having paddle-shaped agitation blades (16 or
20); and polymerizer 10 was the same as the polymerizer
used in Example 5, except that the number of holes of
the perforated plate was changed to four (wherein the
four holes were arranged such that a square is formed
when lines connecting the holes are drawn on the sur-
face of the perforated plate); the length of each guide
5 was changed to 9 m, and the length of the polymerizer
casing was increased accordingly. During the operation
of polymerizer 10, the prepolymer was caused to pass
through the holes of the perforated plate at a rate of
23 g/min per hole.
Specifically, production of the PTT resin was per-
formed as follows. DMT and a mixture of TMG and tita-
nium tetrabutoxide (amount of titanium tetrabutoxide =
0.1 % by weight, based on the weight of DMT) (DMT/TMG
molar ratio = 1/1.5) were continuously charged into es-
terification reaction vessel 11, and polymerization was
performed under the conditions indicated in Tables 1
and 4, thereby obtaining a polytrimethylene terephtha-
late (PTT) resin. During the polymerization, trimethyl
phosphate (stabilizer) was continuously added to first
vertical agitation type polymerizer 15 in an amount of
20 ppm by weight, based on the weight of the polymer.
The results are shown in Table 1.
Prepolymer A which was fed into the final polymer-
izer 10 satisfied the requirements of the present in-
vention, and the obtained PTT resin B had a high mo-
lecular weight, a narrow molecular weight distribution,
a low terminal carboxyl group content, and excellent
color. Further, the degree of discoloration of the ob-
tained resin occurring by heating was very small.
The obtained polytrimethylene terephthalate resin
was immersed in cool water having a temperature of 5 ° C
to thereby solidify the PTT resin. The solidified PTT
resin was cut into pellets, each having a weight of 20
mg. The amount of polymer powder (which had adhered to
the pellets) was as low as 0.01 % by weight, and the
pellets had a crystallinity as low as 5 %. Therefore,
the obtained pellets were not easily broken and easy to
handle.
Example 10
Polymerization was performed in substantially the
same manner as in Example 9, except that nitrogen gas E
was introduced through inlet 6 into polymerizer 10 in
an amount indicated in Table 1, thereby obtaining a
polytrimethylene terephthalate (PTT) resin (the condi-
tions employed in this Example are indicated in Tables
1 and 4). The results are shown in Table 1.
Prepolymer A which was fed into the final polymer-
izer 10 satisfied the requirements of the present in-
vention, and the obtained PTT resin B had a high mo-
lecular weight, a narrow molecular weight distribution,
a low terminal carboxyl group content, and excellent
color. Further, the degree of discoloration of the ob-
tained resin occurring by heating was very small.
Example11
Polymerization was performed in substantially the
same manner as in Example 9, except that the production
system as shown in Fig. 6 was employed instead of the
production system as shown in Fig. 5 (i.e., except that
horizontal agitation type polymerizer 22 equipped with
a uniaxial stirrer having disc-shaped agitation blades
23 was used instead of second vertical agitation type
polymerizer 19), thereby obtaining a polytrimethylene
terephthalate resin (the conditions employed in this
Example are indicated in Tables 1 and 5). The results
are shown in Table 1.
Prepolymer A which was fed into the final polymer-
izer 10 satisfied the requirements of the present in-
vention, and the obtained PTT resin B had a high mo-
lecular weight, a narrow molecular weight distribution,
a low terminal carboxyl group content, and excellent
color. Further, the degree of discoloration of the ob-
tained resin occurring by heating was very small.
Example 12
Polymerization was performed in substantially the
same manner as in Example 11, except that nitrogen gas
E was introduced through inlet 6 into polymerizer 10 in
an amount indicated in Table 1, thereby obtaining a
polytrimethylene terephthalate (PTT) resin (the condi-
tions employed in this Example are indicated in Tables
1 and 5).
Prepolymer A which was fed into the final polymer-
izer 10 satisfied the requirements of the present in-
vention, and the obtained PTT resin B had a high mo-
lecular weight, a narrow molecular weight distribution,
a low terminal carboxyl group content, and excellent
color. Further, the degree of discoloration of the ob-
tained resin occurring by heating was very small.
Examples 13 and 14
In each of Examples 13 and 14, polymerization was
performed in substantially the same manner as in Exam-
ple 12 (in which the production system as shown in Fig.
6 was employed), except that, in Example 13, guides 5
provided in polymerizer 10 were changed to chains, each
formed by the combination of elliptical rings (the di-
ameter of a wire forming each ring was 3 mm; the major
axis of the ellipse defined by each ring was 50 mm; and
the curvature of each ring was 2 0 mmF)) , and that, in
Example 14, guides 5 provided in polymerizer 10 were
changed to wires, each having a diameter of 5 mm and
having welded thereto discs (each having a diameter of
20 mmF) and a thickness of 3 mm) at intervals of 200 mm
in a manner such that the wire penetrates the center of
each disc, thereby obtaining a polytrimethylene
terephthalate resin (the conditions employed in these
Examples are indicated in Tables 1 and 6) . The results
are shown in Table 1.
Prepolymer A which was fed into the final polymer-
izer 10 satisfied the requirements of the present in-
vention, and the obtained PTT resin B had a high mo-
lecular weight, a narrow molecular weight distribution,
a low terminal carboxyl group content, and excellent
color. Further, the degree of discoloration of the ob-
tained resin occurring by heating was very small.
Comparative Example 5
The prepolymer obtained in Example 13 was immersed
in cool water having a temperature of 5 °C to thereby
solidify the prepolymer. The solidified prepolymer was
then cut into pellets, and the pellets were dried at
120 °C in air. 100 kg of the dried pellets were
charged into a 300 liter tumbling solid-phase polymer-
izer, and solid-phase polymerization was performed at
205 °C for 72 hours, while flowing nitrogen gas into
the polymerizer at a rate of 100 liters/hr, thereby
obtaining a polytrimethylene terephthalate (PTT) resin.
The results are shown in Table 1.
The obtained PTT resin had a satisfactorily high
molecular weight. However, the obtained resin had a
broad molecular weight distribution. Further, the ob-
tained pellets not only had attached thereto polymer
powder in an amount as large as 1.0 % by weight, but
also had a crystallinity as high as 55 %, and hence.
the obtained, pellet was brittle. If it is attempted to
transfer the obtained pellets by means of a feeder or a
pneumatic conveyer, the pellets would be broken,
thereby forming a large amount of polymer powder.
Comparative Example 6
Polymerization was performed in substantially the
same manner as in Example 12, except that the amount of
a polytrimethylene terephthalate resin produced per day
was reduced to 75 kg, and that polymerizer 10 was not
used, thereby obtaining a polytrimethylene terephtha-
late resin. The results are shown in Table 1.
The obtained PTT resin had a low polymerization
degree, a broad molecular weight distribution and a
high terminal carboxyl group content. Further, the de-
gree of discoloration of the obtained resin occurring
by heating was very large
Example 15
Polymerization was performed in substantially the
same manner as in Example 1, except that the system as
shown in Fig. 2 was employed in which inert gas was in-
troduced into the polymerizer by means of inert gas ab-
sorption device Nl, and that the polymerization was
performed under the conditions indicated in Table 1.
Perforated plate N4 provided in inert gas absorption
device Nl had nine holes, each having a diameter of 1
mm, in which the holes of the perforated plate are ar-
ranged such that a checkered pattern is formed when
lines connecting the holes are drawn on the surface of
the perforated plate. Each of guides N5 used in inert
gas absorption apparatus Nl was a wire made of
stainless steel, which had a circular cross-section,
and had a diameter of 5 mm and a length of 3 m. Guides
N5 were attached to perforated plate N4 so that each
hole of perforated plate N5 had one guide N5 attached
thereto. Nitrogen gas E was fed into the gas absorp-
tion apparatus so that the internal pressure thereof
was 0.11 Pa. Prepolymer N5" was allowed to fall along
and in contact with guides N5 so as to cause the pre-
polymer to absorb and contain nitrogen gas. Transfer-
ring pump N7 was operated while observing the prepoly-
mer inside the gas absorption apparatus through the ob-
serving window, so that almost no prepolymer was accu-
mulated at the bottom of the gas absorption apparatus.
Prepolymer A withdrawn from inert gas absorption appa-
ratus Nl contained very small bubbles. After conduct-
ing the production of the PTT resin for a while in the
above-mentioned manner, the feeding of nitrogen gas
E into inert gas absorption apparatus Nl was stopped.
and the difference in the internal pressure of inert
gas absorption apparatus Nl before and after the stop-
ping of the feeding of nitrogen gas was measured. As a
result, it was found that the difference in the amount
of nitrogen gas was 0.5 mg per gram of the prepolymer.
This difference in the amount of nitrogen gas was de-
fined as the amount of nitrogen gas which was absorbed
by and contained in the prepolymer. Using the thus ob-
tained amount of nitrogen gas absorbed by and contained
in the prepolymer, the amount of nitrogen gas intro-
duced into the polymerizer was calculated on the as-
sumption that all nitrogen gas contained in the pre-
polymer was introduced into the polymerizer. The re-
sults are shown in Table 1. When the prepolymer fal-
ling in polymerizer 10 was observed through observing
window 4, it was found that the prepolymer was in a
foaming state and contained a large amount of bubbles.
The resultant polytrimethylene terephthalate resin had
a high molecular weight, a narrow molecular weight dis-
tribution and a low terminal carboxyl group content,
and excellent color. Further, the degree of discolora-
tion of the obtained resin occurring by heating was
very small.
Example 16
Polymerization was performed in substantially the
same manner as in Example 9, except that the second
vertical agitation type polymerizer was replaced by a
free-fall polymerizer (which is the same as polymerizer
10 of Fig. 5 except that guides 5 were removed so that
the prepolymer was caused to fall freely from the holes
of perforated plate 3), thereby obtaining a poly-
trimethylene terephthalate resin (the conditions em-
ployed in this Example are indicated in Tables 1 and 4).
The free-fall polymerizer was operated at 260 ° C under
a pressure of 100 Pa. The results are shown in Table 1
Prepolymer A which was fed into the final polymer-
izer 10 satisfied the requirements of the present in-
vention, and the obtained PTT resin B had a high mo-
lecular weight, a narrow molecular weight distribution,
a low terminal carboxyl group content, and excellent
color. Further, the degree of discoloration of the ob-
tained resin occurring by heating was very small.
Example 17
Polymerization was performed in substantially the
same manner as in Example 9, except that the second
vertical agitation type polymerizer was replaced by a
thin film type polymerizer (which is the same as poly-
merizer 10 of Fig. 5 except that the perforated plate
had 4 holes arranged, in a line, and that a flat board
is vertically provided as guide 5, so that prepolymer A
is allowed to fall in the form of a film on the flat
board), thereby obtaining a polytrimethylene terephtha-
late resin (the conditions employed in this Example are
indicated in Tables 1 and 4). The thin film type poly-
merizer was operated at 260 ° C under a pressure of 100
Pa. The results are shown in Table 1.
Prepolymer A which was fed into the final polymer-
izer 10 satisfied the requirements of the present in-
vention, and the obtained PTT resin B had a high mo-
lecular weight, a narrow molecular weight distribution,
a low terminal carboxyl group content, and excellent
color. Further, the degree of discoloration of the ob-
tained resin occurring by heating was very small.
INDUSTRIAL APPLICABILITY
The polytrimethylene terephthalate resin of the
present invention can be stably produced on a commer-
cial scale without performing solid-phase polymeriza-
tion. Further, the polytrimethylene terephthalate
resin of the present invention has an intrinsic viscos-
ity within an appropriate range, a narrow molecular
weight distribution, and excellent color, and hence,
can advantageously be used for stably producing a fiber
or shaped article which has high strength and excellent
color on a commercial scale.
We claim:
1. A poly trimethylene terephthalate resin comprising:
90 to 100 mole % of trimethylene terephthalate recurring units, and
0 to 10 mole % of at least one comonomer unit said trimethylene
terephthalate recurring units,
said poly trimethylene terephthalate resin having the following
characteristics (A) to (D):
(A) an intrinsic viscosity (?) of from 0.8 to 4.0 dl/g;
(B) a molecular weight distribution of from 2.0 to 2.7 in
terms of the Mw/Mn ratio, wherein Mw represents the
weight average molecular weight of said
poly trimethylene terephthalte resin and Mn represents the
number average molecular weight of said
poly trimethylene terephthalate resin;
(C) a psychometric lightness L-value (L-1) of from 70 to 100
and a psychometric chroma b*-value (b*-l) of from -5 to
25; and
(D) a psychometric lightness L-value (L-2) of from
70 to 100 and a psychometric chroma b*-value (b*-2) of
from -5 to 25 as measured after heating said poly-
trimethylene terephthalate resin at 180 " C for 24 hours
in air.
2. The polytrimethylene terephthalate resin according
to claim 1, wherein said polytrimethylene terephthalate
resin has an intrinsic viscosity [?] of from 1.25 to 2.5
dl/g.
3. The polytrimethylene terephthalate resin according
to claim 1 or 2, which has a terminal carboxyl group
content of from 0 to 20 meq/kg.
4. The polytrimethylene terephthalate resin according
to any one of claims 1 to 3, which has a molecular
weight distribution of from 2.0 to 2.6.
5. The polytrimethylene terephthalate resin of any one
of claims 1 to 4, which is in the form of pellets,
6. The polytrimethylene terephthalate resin according
to claim 5, wherein said pellets have an average weight
of from 1 to 1000 mg per pellet, and wherein said pel-
lets contains a powder of said polytrimethyfene terephthaiate resin in an amount
of 0 to 0.5% by weight,, based on the total weight of said peliets , which powder
passes through a 30-mesh filter and does not pass through a 300-mesh filter.
7. The polytnm ethyiene terephthaiate resin according to claim 5 or 6, wherein
said peiiets have a crystallinity (Xc) of 40% or less, wherein said crystallinity is
defined by the following formula:
Xc (%) - { ? X (?s-?a) }/ { ?, X (?c-?a)} X 100
wherein ?a is 1.300 g/cm3 which is an amorphous density of trimethylene
terepbthalate homopolymer, ? is 1 431 g/cm3 which is a crystal density of
trimethylene terephthaiate homopoiymer, an ?s represents a density (g/cm3) of
said pellets,
8. A method for producing a polytrimethyiene terephthaiate resin, which
comprises:
(1) providing a molten form of a trimethylene terephthaiate prepolymer
comprising:
90 to 100 mole % of trimethylene terephthaiate recurring units, and
0 to 10 mole % of at least one comanomer unit other than said
trimethylene
terephthaiate recurring units,
said trimethylene terephthaiate prepolymer having an
intrinsic viscosity [?] of from 0.2 to 2 dl/g. and
(2) polymerizing said molten form of a trimethylene
terephthaiate prepolymer at a temperature which is 5°C or
more higher than the crystalline melting point of said
prepolymer but is not higher than 280°C under reduced
pressure by the guide wetting fall process in which said
prepolymer is allowed to fall along and in contact with the
surface of a guide so that polymerization of said prepolymer
is effected during the fall thereof.
9. The method according to claim 8, wherein said molten prepolymer
is continuously fed to a polymerization reaction zone for effecting
the polymerization of said prepolymer in said step (2) and the
resultant poly trimethylene terephthaiate resin produced in said step
(2) is continuously withdrawn from said polymerization zone, so
that said step (2) for prepoiymer polymeriza-
tion is continuously performed.
10. The method according to claim 8 or 9, wherein said
guide has at least one portion selected from the group
consisting of a concave portion, a convex portion and a
perforated portion.
11. The method according to any one of claims 8 to 10,
wherein said prepolymer falling along and in contact
with the surface of said guide is in a foaming state.
12. The method according to any one of claims 8 to 11,
wherein the polymerization in said step (2) is performed,
while introducing inert gas to said polymerization reac-
tion zone.
13. The method according to claim 12, wherein the
amount of said inert gasN introduced to said polymeriza-
tion reaction zone is in the range of from 00.5 to 100
mg per gram of said polytrimethylene terephthalate resin
withdrawn from said polymerization reaction zone.
14. The method according to claim 12 or 13, wherein at
least a part of said inert gas is introduced to said po-
lymerization reaction zone in a manner wherein the in-
troduction of the part of said gas is conducted sepa-
rately from the feeding of the trimethylene terephtha-
late prepolymer to the polymerization reaction zone.
15. The method according to any one of claims 12 to 14,
wherein at least a part of said inert gas is introduced,
to said polymerization reaction zone in such a form as
absorbed or contained in said trimethylene terephthalate
prepolymer.
16. The method according to any one of claims 8 to 15,
wherein said prepolymer has an intrinsic viscosity [?]
of from 0.5 to 2.0 dl/g and a terminal carboxyl group
ratio of 50 % or less in terms of the molar ratio (%) of
the terminal carboxyl groups of the prepolymer to all
terminal groups of the prepolymer.
17. The method according to any one of claims 8 to 16,
wherein said prepolymer is produced by at least one po-
lymerization method selected from the following methods
(a) to (d):
(a) a polymerization method using a vertical agita-
tion type polymerizer;
(b) a polymerization method using a horizontal agi-
tation type polymerizer;
(c) a polymerization method using a free-fall poly-
merizer having a perforated plate; and
(d) a polymerization method using a thin film type
polymerizer.
18. The method according to claim 17, wherein said pre-
polymer is produced by said method (b).
19. A polytrimethylene terephthalate resin produced by
the method of any one of claims 8 to 18.
A polytrimethylene terephthalate resin comprising:
90 to 100 mole % of trimethylene terephthalate recurring
units, and 0 to 10 mole % of at least one monomer unit
5 obtained from a comonomer other than the monomers used
for forming the recurring units and copolymerizable with
at least one of the monomers used for forming the recur-
ring units, which resin has the following characteris-
tics: (A) an intrinsic viscosity [?] of from 0.8 to 4.0
10 dl/g; (B) an Mw/Mn of from 2.0 to 2.7; (C) a psychomet-
ric lightness L-value (L-1) of from 70 to 100 and a
psychometric chroma b*-value (b*-l) of from -5 to 25;
and (D) a psychometric lightness L-value (L-2) of from
70 to 100 and a psychometric chroma b*-value (b*-2) of
15 from -5 to 25 as measured after heating the resin at
180 °C for 24 hours in air.

Documents:

1542-kolnp-2004-granted-abstract.pdf

1542-kolnp-2004-granted-claims.pdf

1542-kolnp-2004-granted-correspondence.pdf

1542-kolnp-2004-granted-description (complete).pdf

1542-kolnp-2004-granted-drawings.pdf

1542-kolnp-2004-granted-form 1.pdf

1542-kolnp-2004-granted-form 18.pdf

1542-kolnp-2004-granted-form 2.pdf

1542-kolnp-2004-granted-form 3.pdf

1542-kolnp-2004-granted-form 5.pdf

1542-kolnp-2004-granted-gpa.pdf

1542-kolnp-2004-granted-letter patent.pdf

1542-kolnp-2004-granted-reply to examination report.pdf

1542-kolnp-2004-granted-specification.pdf

1542-kolnp-2004-granted-translated copy of priority document.pdf


Patent Number 218985
Indian Patent Application Number 01542/KOLNP/2004
PG Journal Number 16/2008
Publication Date 18-Apr-2008
Grant Date 16-Apr-2008
Date of Filing 13-Oct-2004
Name of Patentee ASAHI KASEI KABUSHIKI KAISHA
Applicant Address 2-6, DOJIMAHAMA 1-CHOME, KITA-KU OSAKA-SHI OSAKA 530-8205 JAPAN
Inventors:
# Inventor's Name Inventor's Address
1 KATSUHIRO FUJIMOTO 3-19-6 SASAGE, KOUNAN-KU YOKOHAMA-SHI, KANAGAWA-KEN 234-0052, JAPAN
2 TSUTOMI HISADA, 2591-13, ONUKICHO 4-CHOME NOBEOKA-SHI, MIYAZAKI-KEN 882-0803 JAPAN
3 YOICHIRO AZUMA, ASAHI KASEI OTAKA APARTMENT 3-705, 1005-1, HIGASHI-TOMII, KURASHIKI-SHI, OKAAMA -KEN 710-0847 JAPAN
PCT International Classification Number C08G63/183
PCT International Application Number PCT/JP03/07567
PCT International Filing date 2003-06-13
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2002-172735 2002-06-13 Japan