Title of Invention

A METHOD OF MAKING A POLYMER USING CONDENSATION POLYESTER

Abstract Embodiments relate to a relatively rapid transesterification process including transesterifying condensation polymers such as polyethylene terephthalate (PET), or other polyesters used in commerce, with a modifying monomer mix containing other monomers to manufacture new polymers containing the pre-condensed moieties. The process preferably only involves transesterification as a reaction mechanism. The process preferably produces a rapid buildup of molecular weight and/or polymer uniformity by the high temperature transesterification of the condensation polymer with the modifying monomer mixture. The process can be performed in any suitable vessel including an extrusion line, and it has the advantage of greatly reduced cycle times over currently used condensation polymer utilization processes such as the recycling of PET into other materials.
Full Text Polymer Manufacturing Process
BACKGROUND
1. Field of the Invention
[0001] Embodiments relate generally to a transesterification process involving at
least the transesterification of polyester terephthalate (PET) or other
polyesters used in commerce, with a modifying monomer mixture to
produce new polymers. The new polymers so produced are useful, for
example, as adhesives in the manufacture of a variety of carpet products
and other textiles, or for other adhesive uses.
2. Description of Related Art
[0002] Esterification typically includes the condensation of organic carboxylic
acids and alcohols to yield ester linkages. Polyesters are made when
multifunctional carboxylic acids are reacted with multifunctional alcohols to
yield polymers containing repeating ester units. Polyesters have become
important polymer components used in a variety of industries.
[0003] The esterification reaction required to manufacture polyester polymers
usually takes a great deal of time compared to other polymerization
reactions. For example, a typical aromatic polyester of moderate
molecular weight can require between 12 and 24 hours to finish whereas
an aromatic styrene polymer prepared by free radical polymerization can
take as little as one hour to complete. There are several reasons for this
increased duration. One reason is that the temperatures required for
esterification are much higher on the order of 200 to 250 degrees
Centigrade than those of other reactions such as free radical
polymerization which require temperatures of only 70 to 100 degrees
Centigrade. Another reason more time is needed is when higher
molecular weight polyesters (such as those greater than 10,000 average
number mw) are the goal. With higher molecular weight polyesters, the
reaction becomes longer when the equivalents of hydroxyl and acid
components are closer to being equal.
[0004] While initially the reaction proceeds rapidly, once reaction temperatures
have been reached the reaction starts slowing down as the free acids and
hydroxyl groups become less concentrated in the mix. As the reaction
slows additional steps and techniques are used to continue the reaction
and create larger and larger molecular weights. With very large molecular
weights (those greater than 30,000 mw) most often the material is
transferred from the original vessel to one where more surface area, heat
and/or agitation can be applied. Even larger molecular weights can be
obtained by using additional processing steps such as solid state reactions
or transesterification.
[0005] The following is an excerpt from Organic Chemistry by Morrison and Boyd,
pages 679-680, second edition: "In the esterification of an acid, an alcohol
acts as a nucleophilic reagent; in hydrolysis of an ester, an alcohol is
displaced by a nucleophilic reagent. Knowing this, we are not surprised to
find that one alcohol is capable of displacing another alcohol from an
ester. This alcoholysis (cleavage by an alcohol) of an ester in called
transesterification." "Transesterification is an equilibrium reaction. To shift
the equilibrium to the right, it is necessary to use a large excess of the
alcohol whose ester we wish to make, or else to remove one of the
products from the reaction mixture. The second approach is the better one
when feasible, since in this way the reaction can be driven to completion."
[0006] When making condensation polyesters, transesterification can be used as
an additional processing step to achieve higher molecular weights with
already condensed polymers or monomers. At higher temperatures the
elimination of an alcohol and subsequent removal of it by vacuum will
greatly increase molecular weight. At some point the end group can be
liberated and removed by heat and/or vacuum thus building molecular
weight. To extend the molecular weight of preformed polymers,
transesterification sometimes follows an initial esterification step where the
monomer mix, usually containing excess glycols, is first reacted to a point
where most of the free carboxylic groups are used up. Or
transesterification can be used alone to create polymers where the
carboxylic groups have been pre-formed into esters with an easily
volatilized alcohol, most commonly methanol. Thus both esterification and
transesterification can be used separately or together in the process of
making polyesters.
[0007] Over the years, many processes have been developed for manufacturing
polyesters. In the 1940's it was discovered that polyester polymers could
be made having very desirable properties such as clarity and high impact
strength through the condensation of aromatic dicarboxylic acids with
glycols using high temperatures and long reaction times to achieve higher
molecular weights. By far the most important synthetic polyester today is
polyethylene terephthalate (PET). This polymer is one where the
multifunctional carboxylic acid is a terephthalate or terephthalic acid and
the multifunctional alcohol is ethylene glycol. PET is a crystalline polymer
that can be used for a variety of items such as film textile, fiber, beverage
bottles, and other types of containers.
[0008] One method of making PET is to start with dimethyl terephthalate and
transesterify with ethylene glycol liberating methanol. As methanol is
removed from the process the molecular weight is driven up. Several
transesterification catalysts have been used for this method. Due to the
environmental problems associated with methanol, it has become more
common to use terephthalic acid and ethylene glycol with a suitable
esterification catalyst. Again there are a number of such catalysts used.
[0009] Esterification of terephthalic acid requires high temperatures, in excess of
200 °C, and long reaction times, sometimes longer than 24 hours. Thus it
becomes a very energy intensive polymer to make. When very high
molecular weights are needed, 50,000 or greater (which is considered low
compared to other polymers), solid state reactors are used to vacuum as
much glycol off as possible thus extending the chain length through
transesterification and the removal of glycol. Additional heat and time are
needed.
[0010] The PET manufacturing segment of the polymer industry has become so
large that the cost of the raw materials of the PET polymer is low in
comparison to other similar performance polymers. Large PET processing
lines dedicated entirely to the manufacture of the PET polymers produce
PET polymer on a continuous basis. Due to this production there has
been a great deal of controversy over the large amounts of PET that are
being recovered from post consumer waste streams. Due to this
abundance of post consumer waste, there have been a large number of
patents issued that concern the utilization of this PET waste. As we
progress in the manufacturing techniques for other monomers and the
need for higher performance materials become greater we will naturally
expect to see the utilization of other condensation polymers to the point
where they become prevalent in the waste streams. This has already
started to happen with PET containing other barrier materials and with
PEN or polyethylene napthalate.
[0011] As the waste stream from recycling started producing waste PET in
abundance there were several patents written to utilize this potential raw
material source. These patents became a technology in their own right.
The first approaches to using PET were geared toward breaking down the
ester linkages through hydrolysis with water or glycolysis. Glycolysis is a
specific form of transesterification where excess glycol is used to degrade
the molecular weight. In this way the individual components of the PET
can be regenerated. In U.S. Pat. No. 4,078,143 issued to Malik, et al.
entitled "Process for depolymerizing waste ethylene terephthalate
polyester", a process is described where PET is broken down by glycolysis
to bis-(2-hydroxy ethyl) terephthalate, a monomer that can be utilized to
reform the PET. In U.S. Pat. No. 4,163,860, issued to Delatte, et al.
entitled "Process for obtaining dimethyl terephthalate from polyester scrap"
methanol is used to transesterify scrap PET back to dimethyl terephthalate
that is purified for use in the PET manufacturing process. In U.S. Pat. No.
4,355,175, issued to Pasztaszeri entitled "Method for recovery to
terephthalic acid from polyester scrap", a method of hydrolyzing the PET
and purifying and recovering the terephthalic acid is described. In U.S.
Pat. No. 4,578,502 issued to Cudmore entitled "Polyethylene terephthalate
saponification process", a process is described wherein PET is broken
down into its monomeric constituents through saponification with alkali. In
U.S. Pat. No. 4,929,749 issued to Gupta, et al. entitled "Production of
terephthalate esters by degradative transesterification of scrap or virgin
terephthalate polyesters", higher boiling alcohols are used to transesterify
the PET into lower molecular weight materials for use as raw materials for
the manufacture of other polymers. In U.S. Pat. No. 5,101,064 issued to
Dupont, et al. entitled "Production of terephthalate esters by degradative
transesterification of scrap or virgin terephthalate polyesters", a process is
described where groups having 6 to 20 carbons are used to degrade the
PET, distill off the glycol byproduct, and recover the diester.
[0012] In U.S. Pat. No. 5,266,601 issued to Kyber, et al. entitled "Process for
preparing polybutylene terephthalate from PET scrap" a method of using
PET by glycolysis and ester exchange with 1,4 butanediol and subsequent
polycondensation is described. In U.S. Pat. No. 5,319,128 issued to
Dupont, et al. entitled "Production of terephthalate esters by degradative
transesterification of scrap or virgin terephthalate polyesters" a method of
tranesterifying PET using higher molecular weight alcohols with 6 to 20
carbons and then recovering the diesters of terephthalate is described. In
U.S. Pat. No. 6,031,128 and 6.075,163 issued to Roh, et al. entitled
"Process for manufacturing terephthalic acid", a process is described for
manufacturing terephthalic acid from waste PET whereby PET is
hydrolyzed to disodium terephthalate and then acid neutralized to recover
the free terephthalic acid. In U.S. Pat. No. 6,472,557 issued to Pell, Jr. et
al. entitled "Process for recycling polyesters", a process for depolymerizing
PET to dimethylterephthalate and then hydrolyzing it to terephthalic acid
for reuse is described. Although all of these processes work, they are all
very energy intensive ways of recycling the PET and do not utilize the time
and energy that has already gone into making the PET polyester. More
often these processes end up costing as much or even more than the cost
of the monomers they are trying to reclaim. This is in large part due to the
low cost of the beginning PET feed stocks and the refined methods for
converting to the starting monomers. Also the additional energy required
to reclaim the monomers from recycled PET adds substantially to the cost.
[0013] In the techniques used below, it is not necessary to take the PET polymer
all the way to its monomeric constituents and thus at least part of the time
and energy of conversion of the terephthalic acid and ethylene glycol is
conserved. However in all cases the transesterification conversion is done
to break down the PET linkages and lower the molecular weight to much
lower oligomeric forms prior to subsequent reactions.
[0014] There also are a number of methods for the utilization of PET as a raw
material for the manufacture of other polymers where terephthalic acid
and/or ethylene glycol can be integrated as one of the components. One
such area is in the use of PET to make polyols that in turn are used for
making urethane foams. In U.S. Pat. No. 4,439,549 issued to Brennan
entitled "Novel aromatic polyester polyol mixtures made from polyethylene
terephthalate residues and alkylene oxides" a method of reacting PET with
glycol to degrade to an oligomeric polyol and then subsequent reaction of
the polyol with an isocyanate moiety to produce rigid foam is described. In
U.S. Pat. No. 4,469,824 issued to Gigsby, Jr., et al. entitled "Liquid
terephthalic ester polyols and polyisocyanate foams therefrom", PET is
digested with diethylene glycol and other glycols with some of the ethylene
glycol and then removed to form a polyol that reacts with an isocyanate to
form a polyisocyanate foam. In U.S. Pat. No. 4,485,196 issued to
Speranza entitled "Liquid phase polyols which are alkylene oxide adducts
of terephthalic esters" a technique of making polyols for further processing
into urethane foams is described. The polyol is further reacted by
ethoxylation or propoxylation to liquefy and inhibit crystallinity. It is then
useful for further conversion into polyurethanes. In U.S. Pat. No.
5,948,828 issued to Reck entitled "Technology development and
consultancy" reclaimed PET is digested with diethylene glycol, insolubles
are removed, and ethylene glycol and free diethylene glycol are removed
to achieve a final hydroxyl value for a polyol. In U.S. Pat. No. 6,573,304
issued to Durant, et al. in June of 2003 entitled "Method for obtaining
polyols and polyol thus obtained" a process for transesterification with
glycols and subsequent removal of free glycols stopping at a narrow
molecular weight is described. These methods utilize excess glycol and
transesterification to shift the equilibrium back to lower molecular weight
entities that can be further processed.
[0015] Some techniques developed utilizing PET have at least partially preserved
some of the ester moieties and therefore some of the time and energy
already used in making the PET. In U.S. Pat. No. 4,977,191 issued to
Salsman entitled "Water-soluble or water dispersible polyester sizing
compositions", a process is described where other polymers are made by
first degrading the PET into oligomers containing the terephthalate moiety
and second building back up the molecular weight using other aromatic or
aliphatic acids. In U.S. Pat. No. 5,726,277 issued to Salsman entitled
"Adhesive compositions from phthalate polymers and the preparation
thereof adhesive compositions are described that are made from PET
that is digested or transesterified with glycols and oxyalkylated polyols,
either ethoxylated or propoxylated. A similar type of reaction is used in
U.S. Pat. No. 5,958,601 issued to Salsman entitled "Water
dispersible/redispersible hydrophobic polyesters resins and their
application in coatings". In this patent however an ester of a fatty acid and
alcohol containing free hydroxyl groups is used in combination with glycols
to degrade the PET polymer to lower molecular weight species before a
molecular weight buildup is done with additional aromatic acids.
[0016] There are additional polymer applications where PET has been used as a
raw material as well. In U.S. Pat. No. 5,820,982 issued to Salsman
entitled "Sulfoaryl modified water-soluble or water-dispersible resins from
polyethylene terephthalate or terephthalates" compositions are described
which contain the terephthalate moieties along with sulfonated aromatic
groups. Such resins are useful for adhesives, ink resins, dye leveling on
polyester and nylon fibers, etc. The process for preparation of these
compositions requires a PET glycolysis step followed by additional acids
and a molecular weight buildup esterification step. The processing times
can be 12 to 24 hours. In U.S. Pat. No. 6,133,329 issued to Shieh, et ai.
entitled "Thermoplastic polyester resin composition" a composition is
described where PET is first digested with a glycol mixture for 3 hours at
high temperatures and then reacted with a natural oil for making it
compatible with hydrocarbon and hydrofluorocarbon blowing agents. In
U.S. Pat. No. 6,512,046 issued to Ueno, et al. entitled "Polymerizable
unsaturated polyester resin composition" several compositions are
described where PET is first depolymerized to achieve a polyester
skeleton, then built back up with a dibasic acid, and further reacted with an
unsaturated monomer. In U.S. Pat. No. 6,534,624 issued to Ito, et al.
entitled "Process for producing alkyd resins" a process is described where
polyester is depolymerized and then esterified in a mixture of alcohols,
glycols, fatty acids, etc. It is noted in this patent that the use of
terephthalic acid has not been in practice in the past with alkyd technology
because this component is more costly than phthalic or phthalic anhydride.
Again all of these patents, some very recent, describe first a
depolymerization step and then an esterification step to build back up
molecular weight to make polymers suitable for other areas of use.
[0017] Other techniques deal with the use of reclaimed PET by cleaning up the
PET from other wastes and using it as a co-blend prior to or in an extruder
with virgin PET or other polymers that can be coextruded with the PET.
Once reheated PET loses intrinsic viscosity (I.V.). Intrinsic viscosity has
become a much easier method of comparing molecular weights of PET
than other more time consuming methods. Once processed, the intrinsic
viscosity drops and its use as a feedstock for the original article made
becomes limited. In U.S. Pat. No. 5,225,130 issued to Deiringer entitled
"Process for reclaiming thermally strained polyester scrap material" mixed
streams of recycled PET are cleaned and post condensed with virgin PET.
In U.S. Pat No. 5,503,790 issued to Clements entitled "Method of
producing disposable articles utilizing regrind polyethylene terephthalate"
recycled PET is used to create articles that are less demanding of higher
intrinsic viscosity. In U.S. Pat. No. 5,554,657 issued to Brownscombe, et
al. entitled "Process for recycling mixed polymer containing polyethylene
terephthalate" a process for recovering PET that involves dissolving the
PET from a recycled stream, removing the solvents, and rinsing the PET is
described. In U.S. Pat. No. 6,399,695 issued to Moriwaki, et al. entitled
'Thermoplastic polyester resin composition" PET is melted with a
polyolefin or glycidyl methacrylate to produce a composite material. In
U.S. Pat. No. 6,583,217 issued to Li, et al. entitled "Composite material
composed of fly ash and waste polyethylene terephthalate" the PET is
mixed with the entitled materials and extruded. In the above references
no reaction of the PET takes place even though there are subsequent
reprocessing steps. There are many other references where recycled
PET is cleaned and used as part of the mixture back into articles such
bottles, film, etc. Limitations due to the lower intrinsic viscosity of the
recycled PET reduce the amount used in critical applications to 5% or
less.
[0018] There are also current practices where PET is modified by transesterifying
with polyethers. These can be glycols or alcohols that have been
ethoxylated or propoxylated. These polymers contain the block segments
of PET with block segments of the polyethers and thus usually exhibit
properties of both. In U.S. Pat. No. 4,785,060 issued to Nagler entitled
"Soil release promoting PET-POET copolymer, method of producing same
and use thereof in detergent composition having soil release promoting
property" PET and a polyoxyethylene polymer are reacted together in a
reactor such that an equilibrium is reached. This reaction is based on
transesterification of the hydroxyl end groups of the polyether with the
ester linkages contained in the PET. In U.S. Pat. No. 6,454,982 issued to
Branum entitled "Method of preparing polyethylene modified polyester
filaments" a method is described wherein polyethylene glycol is reacted
into PET under transesterification conditions and solid stated to a higher
intrinsic viscosity.
[0019] In the referenced documents, glycols, polyethers, or simple glycol
monoesters are used to degrade or lower the molecular weight of the PET
in order to get to monomeric or oligomeric forms of terephthalic acid that
can be further utilized as a polyol source for urethanes, to use as adhesive
components with glycidyl ethers to form epoxies, or as coatings and/or
adhesives.
[0020] Another polymer of commerce is polyethylene naphthalate PEN. Within
the last few years there has been much activity regarding the use of PET
with PEN polymers. This is due in part to better properties such as clarity,
strength, and increased crystallinity that translates to better barrier
properties obtained with PEN. However, PEN is much more expensive
than PET. Therefore, several processes for making copolymers of the two
have been developed. In U.S. Pat. No. 5,902,539 issued to Schmidt, et al.
entitled "Process for making PEN/PET blends and transparent articles
therefrom" a process is described where ethylene glycol is used to reduce
the intrinsic viscosity and increase the range of use for PET and PEN
copolymers.
[0021] The following is an excerpt from U.S. Pat. No. 6,414,063, issued to
Bassam, et al. entitled "Nucleated pet/pen polyester compositions." "It is
known that medium content PET/PEN compositions (compositions with
PET:PEN ratios around 50:50) are amorphous in nature. The range of
compositions which display this amorphous behaviour is generally
accepted to be around PET:PEN=20:80 to PET:PEN=80:20, as described
by two PEN manufacturers-Shell (see FIG. 1 of presentation to "BevPak"
conference, Spring 1995, U.S.A) and Hoechst-Trevira (page 4 of
Polyclear.RTM. N technical literature). The disadvantage of this behaviour
is that the use temperature of compositions in the 80/20 to 20/80 region is
substantially reduced. The use temperature is dependent on the glass
transition temperature (Tg) in this region. In contrast, the use temperature
of PET/PEN compositions with the crystalline melt temperature (Tm). Tm is over 100 °C higher than the
Tg for PET/PEN compositions; hence resulting in the substantial reduction
in use temperature observed in the 20/80 to 80/20 composition region.
The same observations on the amorphous/crystalline nature of PET/PEN
compositions were also made by Lu and Windle (see FIG. 2 in Polymer 36
(1995), pages 451 459) and Andresen and Zachmann (Colloid & Polymer
Science 272 (1994), page 1352). Andresen and Zachmann also found
that blends of PET and PEN formed a single phase within 2 minutes of
melting. This is usually good evidence for rapid formation of a PET/PEN
copolyester by transesterification. Thus the behaviour of PET/PEN blends
and copolymers can be expected to be the same with regards to
crystallisation during all melt processing operations. In the case of bottle
manufacture using PET/PEN copolymers and blends, U.S. Pat. No.
5,628,957 (to Continental PET Technologies Inc.) states that mid-range
PET/PEN compositions containing 20 to 80% PEN are substantially
amorphous and describes the use of an additional strain-hardenable (ie.
crystallisable) layer for these mid-range PET/PEN bottles."
[0022] It is especially interesting to note from this patent that the blends formed a
single phase within 2 minutes of melting. Presumably from this and
information presented in the description one can surmise that ester
compatibility increases the rate of transesterification. Also, it can be
inferred that PET and PEN copolymer combinations have been made via
melting and/or processing since combinations of the two polymers were
started. Again transesterification of the two is the chemistry that makes
this happen. In U.S. Pat. No. 6,586,558 issued to Schmidt, et al. entitled
"Process for making PEN/PET blends and transparent articles therefrom"
glycols are used to lower the intrinsic viscosity and allow more
processable viscosities for blends of these two polymers. Again
transesterification allows this to occur.
[0023] While there has been a lot of activity directed toward utilizing PET as a
raw material to manufacture other polymers or as a composite material,
PET is not being utilized in these polymers as a raw material. The
problems that exist with these prior techniques include raw material
contamination, difficulty of reaction, and incompatibility with one or more of
the other reactive groups. For instance, in U.S. Pat. No. 5,250,333 issued
to McNeely, et al. entitled "Modified polyethylene terephthalate" there is
described compositions where other alkoxylated polyols and dicarboxylic
acids are used in combination with terephthalic acid and ethylene glycol to
produce a less crystalline form of PET. Indeed there are many
applications that use terephthalate moieties but require less crystallinity
than that of PET. For instance, there are many film applications that
require less crystallinity for more elastomeric properties. The polyois
mentioned in the previous paragraphs are another example. In U.S. Pat.
No. 6,428,900 issued to Wang entitled "Sulfonated copolyester based
water dispersible hot melt adhesive" a polyester which contains water
dispersible sulfonated branched copolyester polymers is described.
These copolyester polymers use difunctional carboxylic acids like
terephthalic acid in their makeup. Crystallinity would inhibit water
redispersibility which is an important aspect of the disclosure. In U.S. Pat.
No. 6,555,623 issued to Yang, et al. entitled "Preparation of unsaturated
polyesters" a process is described where MPD (methyl propanediol) is
used along with aromatic diacids such as terephthalic acid and maleic
anhydride to produce unsaturated polyesters suitable for further reaction
through the unsaturated group. Again polymer crystallinity is to be
avoided.
[0024] There are a number of polymers that currently utilize phthalic anhydride as
a preferred difunctional aromatic acid. One reason for this is that for
practical considerations one of the acid groups has already been reacted
and is an anhydride. This lowers the weight percent needed in the
subsequent polymers being made. In addition phthalic anhydride
esterifies at lower temperatures than terephthalic acid. Using terephthalic
acid as an alternate would not be as economical to begin with. But
terephthalic acid could be used if the right process to use recycled PET
were available that would eliminate this economical difference.
[0025] There are a number of polymers containing ester linkages and the number
and scope of polymers that utilize or could utilize the raw materials that
make up PET or other condensation polymers of commerce are too
numerous to list within the scope of this write. The following broad based
articles of commerce all use or have used terephthalic acid (or aromatic
acids like phthalic acid or anhydride) and/or ethylene glycol in their
monomer makeup:
(1) Adhesives: either hot melt, water borne, or reactive;
(2) Ink resins: both as the binding agent and the carrier vehicle;
(3) Unsaturated resins: alone or in combinations with reactive
diluents such as acrylics or styrene for composite mixtures with
fiberglass, carbon fiber, etc.;
(4) Alkyd resins: both long and short alkyds for coatings and
paint applications;
(5) Urethanes: As the polyoi portion together with isocyanates
to form adhesives, structural resins, or foams;
(6) Films: Less crystalline films for shrink wrap, laminating, etc.;
and
(7) Polyols for powder coatings or fusable coatings.
[0026] As described above, PET (either virgin or recycled) is recognized as a
material that can be used to make more PET, PET composites, or other
polymers that contain terephthalate groups. The processes that have
been used to make these materials contain within their steps glycolysis (or
hydrolysis) of the ester linkages to create the beginning monomers such
as terephthalic acid, or a much lower molecular weight terephthalate
oligomer that can be reacted to generate more PET or other polymers
through esterification. In no circumstance has there been activity that
indicates advantage taken of the high molecular weight of PET (polyester
polymers) being used to build higher molecular weight, on the order of
10,000 to 20,000, through transesterification with a lower molecular weight
polyester.
[0027] In U.S. Patent 7,157,139 issued to Salsman (Jan. 2007) the issue of
preservation of the high molecular weight of PET is addressed. The high
molecular weight in PET is used to build the molecular weight of a lower
molecular weight modifying polymer. The process described therein
preferably involves two-steps that can be used to take full advantage of
the high molecular weight of a precondensed polymer, like PET, to
produce a new high molecular weight polymer. The first step, which
involves no polymer of commerce, takes all the other monomers that are
to be contained within the finished polymer, and reacts them first through
esterification to form a modifying polymer containing terminal hydroxyl
groups. In the second step, a commercially available condensation
polymer such as PET is transesterified with the modifying polymer using
heat and agitation to form the finished polymer.
[0028] The description herein of certain advantages and disadvantages of various
features, embodiments, methods, and apparatus disclosed in other
publications is not intended to limit the scope of the present embodiments.
Indeed, the preferred embodiments may include some or all of the
features, embodiments, methods, and apparatus described above without
suffering from the same disadvantages.
SUMMARY OF THE EMBODIMENTS
[0029] It is a feature of an embodiment to provide a process for manufacturing a
polyester polymer. Still another feature is to provide a process for
manufacturing a polyester polymer from PET or other commercially
available condensation polymers.
[0030] An additional feature of the embodiments is to provide a process for
modifying PET or other commercially available condensation polymers.
Yet another feature is to provide a process for modifying PET or other
commercially available condensation polymers without degradation to form
high molecular weight cross-linked polymers.
[0031] It is an additional feature of the embodiments to provide a process for
modifying PET or other commercially available condensation polymers by
utilizing a plurality of appropriate monomers. Still an additional feature is
to provide a process for modifying PET or other commercially available
condensation polymers by transesterifying the appropriate monomer mix
with the PET or other commercially available condensation polymers.
[0032] In accordance with these and other related features, the embodiments
provide a process for manufacturing a polyester polymer from PET or
other commercially available condensation polymers. The process
involves selecting a beginning monomer mix from a plurality of appropriate
monomers and transesterifying with the PET or other commercially
available condensation polymers to form a useful new polymer. No
polyesterification is used in the process.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] The terminology used herein is for the purpose of describing particular
embodiments only, and is not intended to limit the scope of the present
invention. As used throughout this disclosure, the singular forms "a," "an,"
and "the" include plural reference unless the context clearly dictates
otherwise. Thus, for example, a reference to "a carpet backing" includes a
plurality of such carpet backings, as well as a single carpet backing, and a
reference to "an adhesive composition" is a reference to one or more
adhesive compositions and equivalents thereof known to those skilled in
the art, and so forth.
[0034] Unless defined otherwise, all technical and scientific terms used herein
have the same meanings as commonly understood by one of ordinary skill
in the art to which this invention pertains. Although any methods and
materials similar or equivalent to those described herein can be used in
the practice or testing of the present invention, the preferred methods,
devices, and materials are now described. All publications mentioned
herein are cited for the purpose of describing and disclosing the various
materials, compositions, and carpet manufacturing methods that are
reported in the publications and that might be used in connection with the
invention. Nothing herein is to be construed as an admission that the
embodiments described herein are not entitled to antedate such
disclosures by virtue of prior invention.
[0035] Monomers in the process disclosed herein typically are molecules that
have molecular weights lower than 1,500 and contain one, two, or more
than two reactive hydroxyl or ester groups that can transesterify with
esters. The phrase "modifying monomer mix" as it is used herein, includes
a monomer or mixtures of monomers used to modify through
transesterification a PET, PEN, or other high molecular weight polyester of
commerce (herein referred to as PET), to achieve a new polymer with new
desired properties.
[0036] The process described herein preferably entails a one step reaction used
to build up a new polymer using PET or other high molecular weight
polyesters. The one step can be accomplished in stages of PET adds to a
modifying monomer mix that has characteristics that both dissolve and
transesterify the PET. Transesterification is a reaction that takes place
when an OH or alcohol group becomes a nucleophile and exchanges take
place at an ester linkage. A polymer preferably is made containing these
groups as a combination of end groups and esterified linkages. While not
intending on being bound by any theory of operation, the inventor believes
that as PET is added, molecular weight builds as the monomers break into
the PET and become oligomer chains containing functional groups.
Subsequent PET is not only believed to be dissolved faster by an oligomer
that now possesses terephthalate moieties, but produces larger and larger
molecular weight chains as more and more PET is added.
Transesterification continuously occurs above the polymer's Tg (glass
transition temperature) and the alcohol generated from the nucleophile
displacement itself becomes a nucleophile that can further react. In this
way the reaction may continue until at some point equilibrium is reached
where no further change in the polymer mixture occurs as the number of
new end groups formed is in equilibrium with the amount and type of new
ester linkages formed and the mixture becomes a homogeneous new
polymer. If the modifying monomer mix contains large segments in
between reactive end groups, then the homogeneous new polymer can
take on characteristics more like the large segments. If the mixture
contains segments with end groups that participate more or less equally in
the transesterification process, then the new polymer becomes a
homogeneous polymer with new properties relative to the starting
materials.
[0037] One of the parameters the inventor believes important to control in
polymer synthesis is molecular weight. In the process disclosed herein, it
is believed that multi-functional monomers containing more than two
reactive groups in the modifying monomer mix introduce sites that provide
cross-link density. Cross-link density can be important in maintaining
molecular weight properties. The final molecular weight may be controlled
by the amount of monomers containing more than two reactive groups in
the modifying monomer mix and the percentage of that modifying
monomer mix reacted with the PET. For instance, if PET is used in
quantities above 60 percent, a lower amount of multifunctional monomers
containing more than two reactive groups are needed in the modifying
monomer mix as PET supplies the linear molecular weight needed to
make a polymer of sufficient molecular weight. Sufficient molecular weight
depends upon the final properties desired and is usually high enough to
achieve some tenacity and or film strength. Further processing of the new
polymer, however, may be desirable.
[0038] With the manufacture of polyesters through condensation alone the
molecular build up is rapid initially and slows down considerably as the
molecular weight increases. The processdescribed herein differs
substantially from other processes that utilize PET in that no esterification
reaction is needed. The polymer process is based completely on
transesterification. This not only opens up the use of a much broader
range of reaction vessels, but also greatly reduces process times since in
polymer synthesis transesterification is a much faster reaction than
polyesterification.
[0039] The process described in the embodiments eliminates many of the
problems associated with the known processes described earlier. Known
processes digest PET to reconstitute the original starting materials, which
in many cases is more expensive than the cost of manufacturing the
starting materials. Once digested, the materials have to be re-condensed,
which is inherently energy inefficient and produces toxic levels of glycol
and dioxane in the waste stream. Thus, only small amounts of PET are
reprocessed in this manner. In contrast, the process of the embodiments
eliminates these problems since it preserves the ester linkages already
formed in the commercially available condensation polymer so that re-
condensation of monomers or oligomers is unnecessary. In this regard, it
becomes easier to consider transesterification as the molecular weight
building step for the lower molecular weight modifying monomer mix. As
PET is added, molecular weight builds, and depending on the amount of
monomers containing more than two reactive groups, cross link density
increases. The reaction mass changes from monomeric, to oligomeric,
and then to polymeric as more PET is added and the reaction proceeds.
[0040] The process of the embodiments preferably involves the rapid
transesterification of a PET polymer with a modifying monomer mix.
Careful monitoring of temperatures and reaction rates are not necessary
with the only requirement being enough heat to transesterify the mixture to
an equilibrium state. Reaction rates are dependent on several factors
including (1) time, (2) temperature, (3) modifying monomer mix, (4)
hydrophilicity of modifying monomer mix, (5) number and type of hydroxyl
functionality contained in the modifying monomer mix, and (6)
transesterification catalyst. Of these factors, higher temperatures are
believed to have the most effect on the time required to complete the
reaction. For example, depending upon the catalyst, good
transesterification of terephthalates starts around 200 °C, greatly
accelerates around 240 °C, and is very rapid around 260 d°C. Reaction
time at 200 °C is about ten hours to transesterify PET with a glycol like
diethylene glycol. Reaction rate is reduced to about one hour at 240 °C
and only fifteen minutes at 260 "C. Heating is not as significant an issue
since water is not being produced to hinder the increase in temperature .
With more hydrophobic modifying monomers and modifying monomers
with secondary hydroxy! groups or esters, these reaction times would be
longer since the solubility of the PET is lower. Those skilled in the art will
appreciate that the choice of the beginning modifying monomer mix may
reduce reaction time, because selecting those monomers that provide
more rapid breakdown may be useful to offset these longer reaction times.
[0041] In some instances, the process of the embodiments does not require the
condensers or condensation receivers that are required in typical
esterification vessels, and consequently, less expensive equipment can be
used. In fact it is possible to complete the reaction in an extruder set up
for the needed dwell times and mixing required. If no condensate is
removed, no venting or condensers are required. The final desired
polymer can be synthesized without further esterification, a major time
consuming step in high molecular weight polyester synthesis. The
embodiments disclosed herein therefore provide advantages such as
lower reaction times, lower waste streams, higher utilization of PET, and
higher finished molecular weights with less energy and time.
[0042] When utilizing the process described in the preferred embodiments, it may
be advantageous to eliminate some of the lower molecular weight glycols
produced in equilibrium in the reaction. For example, in the case of PET,
it may be advantageous to remove some ethylene glycol as it is formed.
In this way the properties imparted by the modifying monomer mix can be
amplified. Removal of some ethylene glycol also may shift the equilibrium
to a higher molecular weight so less monomers containing more than two
reactive groups are needed for molecular weight gain through cross link
density. This allows for the production of more linear polymers. If a
monomer is used that has ester end groups such as a methyl ester, then
methanol is produced in the reaction and can be removed to extend
molecular weight.
[0043] The staged addition of the PET or condensation polymer may become
more relevant as the total level used in making new polymers is increased
above about 40 percent. At this point, it may become difficult to maintain
the PET in a suspended state in a reactor, and problems can arise as the
PET reaches its melting point and is more compatible with itself than with
the modifying monomer mix. If the PET is added in stages of increasing
amounts to the modifying monomer mix, it is possible to produce new
polymers that contain more than 90 percent of the PET.
[0044] Staging the addition of the condensation polymer and allowing some
equilibrium to be reached at each stage may reduce problems in an
agitated reactor. The problems are much less pronounced if the process
is performed within an extruder. However, other problems such as
incompatibility between the PET and the modifying monomer mix can
make extruder reactions more difficult, when compared to an agitated
reactor.
[0045] The process described herein enables production of a a polymer in two
parts. First, a polymer can be made in a reactor using PET to build
properties such as molecular weight. Then, additional PET can be added
in an extruder to create an even higher molecular weight polymer with
properties that only very high molecular weight polyester polymers can
achieve.
[0046] One of the purposes for staging the addition of PET is in allowing each
addition to react in before additional material is added. A secondary
purpose is to allow the temperatures to come back to a level where rapid
transesterification can occur. One can readily see that with the proper
equipment, the PET staging could be part of a continuous feed system
that maintains the reaction conditions at optimum temperatures and
optimum amount of fresh PET, until the entire amount of PET needed has
been added.
[0047] This process can be used for generating polymers for a variety of
applications. Lower molecular weight polymers, with subsequently lower
melting points, provide excellent adhesives. Hydroxyl-terminated resins
prepared in accordance with the embodiments described herein can be
used as polyols for further reaction with epoxies or isocyanates in
urethane production. Slightly higher molecular weight polymers prepared
in accordance with the embodiments can be used as coatings such as hot
melt coatings or powder coatings. Higher molecular weight polymers
prepared in accordance with the embodiments also can be used as fibers.
Further uses could involve augmentation of current film or fiber forming
resins. Further processing of the polymers prepared in accordance with
the embodiments with anhydrides could yield acid-terminated polymers for
neutralization with bases and modified water dispersibility.
[0048] The preferred embodiments described herein relate to a method of making
a polymer using a commercially available condensation polyester as a raw
material that includes selecting a modifying monomer mix, and
transesterifying the modifying monomer mix with the commercially
available condensation polyester at a quantity predetermined by an end
use application, to produce a final polymer. In accordance with the
process, the modifying monomer mix includes at least one monomer, the
at least one monomer preferably being a molecule including a hydroxyl or
an ester, that is capable of participating in transesterification reactions,
and that has a molecular weight of less than 1500. The modifying
monomer mix preferably does not include components derived from the
commercially available condensation polyester.
[0049] Suitable commercially available condensation polyesters useful as a raw
material in the processes described herein include those capable of
transesterification with the modifying monomer mixture. Preferably, the
commercially available condensation polyesters are those selected from
PET, PBT, PEN, PTT (polytrimethylene terephthalate), and most
preferably, these condensation polymers are recycled from existing
materials containing these materials. The commercially available
condensation polyesters typically are used in an amount ranging from
about 30 to about 96 weight percent, based on the total weight of the
polymer produced, and preferably from about 60 to about 80 weight
percent. Skilled artisans are capable of selecting a suitable commercially
available condensation polyester for use in the embodiments, using the
guidelines provided herein.
[0050] The modifying monomer mix useful in the processes described herein
preferably include those with pendant hydroxyl or ester groups, and
preferably, although not necessarily, have a molecular weight of less than
about 1500. The molecular weight can be calculated from the structure
from the monomer, or is already known from manuals (e.g., trimethylol
propane has a molecular weight of about 134). Preferably, the molecular
weight of the monomer mix is less than about 1,300, and more preferably
less than about 1,200, wherein the molecular weight is the total molecular
weight of all of the monomers used in the mixture.
[0051] The monomer mix may include a single monomer, or a mixture of
monomers. Suitable monomers include, but are not limited to alcohols,
acids, polyethoxylates, ethoxylate condensates, esters, di-esters, tri-
esters, and amines and amides with functional alcohol groups. Suitable
alcohols include, but are not limited to butanol, hexanol, lauryl alcohol,
decanol, glycerine, trimethylolpropane, neopentyl glycol, ethylene glycol,
sorbitol, pentaerythritol, cyclohexane dimethanol, stearyl alcohol, and the
like. Suitable acids include, but are not limited to adipic, lauric, palmitic,
stearic, oleic, behenic, linolenic, succinic, maleic, maleic anhydride,
butanoic, phthalic, phthalic anhydride, isophthalic, terephthalic, trimellitic
anhydride, and the like. Suitable polyethoxylates include, but are not
limited to diethylene glycol, triethylene glycol, polyethylene glycol 200,
polyethylene glycol 400, polyethylene glycol 600, polyethylene glycol 800,
polyethylene glycol 1000, and the like. Suitable ethoxylate condensates
include, but. are not limited to 1 to 25 moles of ethylene oxide on the
alcohols or acids listed above. Suitable esters, di-esters, and tri-esters
include, but are not limited to the acids and the (alcohols, polyethoxylates,
or ethoxylate condensates) above such as butyl laurate, ethylene glycol
distearate, cyclohexane dimethanol dioleate, etc. Suitable amines or
amides with functional alcohol groups include, but are not limited to
ethylene oxide condensates of amines. It is preferred in the embodiments
that the monomers used to formulate the monomer mix are not the same
monomers used to make the commercially available polyester with which it
is reacted.
[0052] The amount of monomers used in the monomer mix typically will vary
depending on the desired use of the resulting polymer. Those skilled in
the art will be capable of determining the amount of monomer mix useful in
the processes described, using the guidelines provided herein.
[0053] The time of reaction and temperature of reaction also may vary depending
on the monomer mix and commercially available polyester. Preferably,
the reaction takes place at a temperature within the range of from about
150 to about 350 °C, preferably from about 200 to about 290 °C, and for a
period of from about 0.5 to about 10 minutes, preferably from about 1 to
about 5 minutes. The embodiments now will be described with reference
to the non-limiting examples.
Examples
[0054] The following examples, unless otherwise stated, were all prepared in a
250 milliliter flask fitted with a condenser, a funnel for the introduction of
polymer adds, a thermometer, a variable speed agitator, a tube for the
introduction of an inert gas, and a heating mantel with a scaled rheostat
controller. The table in the examples represent the ingredients,
percentage of each, amount in grams charged, and number and quantity
of staged adds in grams. The PET (polyethylene terephthalate) used was
repelletized PET obtained from the recycling of PET beverage bottles.
The PEN (polyethylene naphthalate) was pelletized, virgin material.
Example 1:

[0055] The bis-diethylene glycol adipate and the Tyzor TPT were added to the flask
and heated to 200°C with agitation. The PET was then added in stages. After
each add the temperature was brought to 250°C with agitation and allowed to
become fully homogeneous and clear before the next staged add. The final
polymer was held at 250°C for an additional 30 minutes before cooling. Total
time for this reaction was 2 hours and 10 minutes. The polymer's properties
improved with each add of PET. Although still somewhat tacky the polymer
exhibited decreased crystallinity at room temperature. There was not enough
room in the flask for more PET adds, but it was evident that higher molecular
weights could be obtained with increasingly levels of PET.
Example 2:

[0056] The bis-diethylene glycol adipate and the Tyzor TPT were added to the
flask and heated to 200°C with agitation. The PET was then added in
stages. After each add the temperature was brought to 250°C with
agitation and allowed to become fully homogeneous and clear before the
next staged add. The polymer was held an 30 minutes at 250°C after all
adds. Total time for this reaction was 2 hours and 30 minutes. The
polymer produced had much higher strength properties relative to
Example 1. PET having higher molecular weight is building up the new
polymers molecular weight with increasing levels. This resin appeared to
be a suitable candidate for a hot melt adhesive.
Example 3:

[0057] The bis-diethylene glycol isophthalate and the Tyzor TPT were added to
the flask and heated to 200°C with agitation. The PET was then added in
stages. After each add the temperature was brought to 250°C with
agitation and allowed to become fully homogeneous and clear before the
next staged add. The polymer was held an additional 30 minutes at 250°C
after the last PET add. Total time for this reaction was 2 hours and 40
minutes. The polymer produced had the appearance of a more non-
crystalline PET polymer, with a clear appearance even after slowly
cooling. At this level of linear monomer the strength properties were much
more like a hot melt resin than PET. The Isophthalic moiety (a known
decrystallizer for PET) was reacting in completely and was believed to
assist in decrystallizing the highly crystalline PET chains.
Example 4:


[0058] The bis-diethylene glycol isophthalate, the ethoxylated glycerine, and the
Tyzor TPT were added to the reaction vessel and heated to 200°C.
Ethoxylated glycerine was used because glycerine alone did not produce
satisfactory results using similar conditions, although glycerine alone may
be satisfactory under other operating conditions. The PET was added in
stages with each stage brought up and back up to 250°C. After all the
PET was added the polymer was kept at 250°C for an additional 30
minutes to insure equilibrium and homogeneity of the polymer. This
reaction proceeded without problems. The polymer had an initial viscosity
after finishing of 4 poise at 175°C. The polymer produced was not
believed to be suitable for a coating polymer because the strength was too
low, but the resulting polymer had properties that were suitable for other
polymer applications.
Example 5:
[0059] A vacuum of 20 In. Hg was exerted on the polymer of Example 4 for 12
minutes at 250°C. The viscosity went to 9 poise at 175°C. The viscosity
of this polymer was 9 poises at 175°C. The strength was good and better
than Example 4 but the polymer did not have adequate resilience for use
as a coating polymer. The resulting polymer would be suitable for other
polymer applications.
Example 6:

[0060] The bis-diethylene glycol isophthalate, the glycerine-25, the trimethylol
propane, and the Tyzor TPT were added to the reaction flask and the
temperature was brought up to 200°C. as rapidly as possible. After the
first staged add of PET and each subsequent add the temperature was
brought up to 250°C rapidly with the rheostat set on 80% after a clear,
homogeneous reaction mass was achieved. After bringing up the
temperature on the last add to 250°C. it was held for 10 minutes and then
a 20 minute vacuum at 250°C was completed before cooling.
[0061] This reaction was much faster than previous ones. The trimethylol
propane appeared to transesterify easily with the PET, and to act as a
better solvent in the initial stages. After all adds were completed, the initial
viscosity was 3 poise at 175°C and after a vacuum of 20 minutes at 250°C
it was 7 poise at 175°C. This material seemed to be less crystalline which
points to either molecular weight or cross-link density helping to prevent
crystallization.
Example 7:

[0062] The cyclohexane dimethanol, the ethoxylated glycerine, and the Tyzor
TPT were added to the reaction vessel and heated to 200°C. The PET
was added in stages with each stage brought up to 250°C and allowed to
become homogeneous and clear before the next stage. After all the PET
was added the polymer was kept at 250°C for an additional 1 hour to
insure equilibrium and homogeneity of the polymer.
[0063] This reaction proceeded without problems. The polymer had an initial
viscosity of 3 poise at 175°C. The cyclohexane dimethanol, a known
decrystallizer for PET, was added to lower the crystallinity. Surprisingly,
the addition did not appear to lower the crystallization temperature, and
did not appear to lower the isophthalates and cross-link density, when
compared to the polymer produced in accordance with Example 4. This
material was easy to grind into a powder and fuse again with temperature.
A possible advantage with the higher crystalline material would be to
produce a fusible coating or thermoforming polymers or compositions that
could be used alone or in combination with other reactive or protective
ingredients to provide a coating or thermoforming composition that had
lower glass transition temperatures but was still a powder at room
temperatures. This formula would be useful as a compound for fusible
coatings or thermoforming applications.
Example 8:

[0064] The polypropylene glycol (M.W. 1000), the trimethylol propane, and the
Tyzor TPT were added to the reaction flask and the temperature was
brought up to 200°C as rapidly as possible. After the first staged add of
PET and each subsequent add the temperature was brought up to 250°C
rapidly with the rheostat set on 80% after a homogeneous reaction mass
was achieved from the previous add. After only 100 grams of PET had
been added the viscosity of the polymer seemed to be growing too rapidly.
[0065] This reaction was different in that a clear phase after the PET adds was
never achieved. The polypropylene glycol may have had some solubility
problems , which may have had an effect on the reactivity of the
secondary hydroxyl group. The reaction resulted in the synthesis of a
gelled polymer suspended in the polypropylene glycol. Once the material
was removed from the flask the gelled polymer separated from the
polypropylene glycol. This polymer, composed of trimethylolpropane and
PET, was strong, resilient, rubber-like and non- crystalline. The viscosity
was greater than 100 Poise at 200°C. The cross-link density was so high
that the molecular weight was essentially approaching infinity rapidly, and
the presence of the polypropylene glycol as a separate phase was
beneficial.
[0066] Hot melt adhesive are polymers that have good adhesion usually to a
variety of substrates. They have relatively low melting point and set up
quickly to resilient but strong polymers.
Example 9:

[0067] The ethoxylated glycerine, the trimethylol propane, and the Tyzor TPT
were added to the reaction flask and the temperature was brought up to
200°C as rapidly as possible. After the first staged add of PET and each
subsequent add the temperature was brought up to 250°C rapidly with the
rheostat set on 80% after a homogeneous and clear reaction mass was
achieved from the previous add. The reaction mass was held at 250°C for
an additional 30 minutes after the last add was clear and homogeneous.
All of the PET was added without difficulties.
[0068] This reaction was far better than using polypropylene glycol or glycerine in
that the extra ethylene oxide on the glycerine not only produced easily
accessable primary hydroxyls, but also seemed as more of a solvent for
the PET. Clear phases at each add were easy to achieve. The viscosity
after the final PET had been added was 6 Poises at 175°C but went to 10
Poise after a 30 minute hold. This material had improved properties of
resiliency, tenacity, adhesion to a variety of substrates, and a relatively low
melting point. The resulting polymer would provide a good hot melt
adhesive or in other adhesive applications.
Example 10:

[0069] The ethoxylated glycerine, the trimethylol propane, and the Tyzor TPT
were added to the reaction flask and the temperature was brought up to
200°C as rapidly as possible. After the first staged add of PET and each
subsequent add the temperature was brought up to 250°C rapidly with the
rheostat set on 80% after a homogeneous and clear reaction mass was
achieved from the previous add. The reaction mass was held at 250°C for
an additional 30 minutes after the last add was clear and homogeneous.
All of the PET was added without difficulties.
[0070] This reaction was similar to Example 8 only in that a larger percentage of
PET was used. All conditions were the same and after the last add had
reached 250°C, and cleared the reaction mass was held for an additional
30 minutes. The polymer had a viscosity of 13 Poise at 175°C. and was
even stronger in properties to Example 8. The polymer had a tendency to
crystallize if cooled too slowly.
Example 11:

[0071] The polyethylene glycol with a molecular weight of 400 and the Tyzor TPT
were added to the reaction flask and the temperature was brought up to
200 C. as rapidly as possible. After the first staged add of PET and each
subsequent add the temperature was brought up to 250°C rapidly with the
rheostat set on 80% after a homogeneous and clear reaction mass was
achieved from the previous add. The reaction mass was held at 250°C for
an additional 30 minutes after the last add was clear and homogeneous.
[0072] This reaction was run mainly to see if enough of the PET had broken down
to provide water solubility. With this much ethylene oxide-containing
material, water dispersibility should be achieved if the reaction is
complete. The material dispersed in water easily and stayed clear for
more than an hour. Since the hydroxyl value would be high on this
polymer and it remained in a liquid state, it would make an excellent polyol
for further reactions.
Example 12:
[0073] The reaction product of Example 10 was further processed. The initial
viscosity was low, 1 Poise at 175°C, so a vacuum was set up and the
product was held for 1 hour total at 250°C and with a 20 mm Hg vacuum.
Samples were taken every 20 minutes. The initial viscosity became 3
Poise at 175°C after 20 minutes of vacuum, 8 Poises after another 20
minutes, and 17 Poises after the final 20 minutes. The removal of the
ethylene glycol as it was formed created larger molecular weights, and it is
conceivable that vacuum could continue to be applied until the molecular
weight was quite high.
Example 13:

[0074] The PEG 400, 20+Alcohol (a 20 carbon linear chain alcohol), and the
Tyzor TPT were added to the reaction flask and the temperature was
brought up to 200°C as rapidly as possible. After the first staged add of
PET and each subsequent add the temperature was brought up to 250°C
rapidly with the rheostat set on 80% after a homogeneous but slightly less
than clear reaction mass was achieved from the previous add. The
reaction mass was held at 250CC for an additional 30 minutes after the last
add was clear and homogeneous. The PET seemed to dissolve and react
without difficulties.
[0075] The 20+Alcohol was added to assess whether some chain termination
with a longer chain aliphatic group would render the polymer less tacky at
room temperature. This apparently worked quite well however upon
standing some of the less massive unreacted 20+Alcohol migrated to the
surface. Although some reacted in apparently not all of the 20+ alcohol
reacted. This migration to the surface could be useful in some
applications and not desirable I in others. The polymer appeared to exhibit
excellent adhesion when poured hot onto a substrate, and consequently,
would make a good hot melt adhesive candidate.
Example 14:

[0076] The PEG 400, ethoxylated stearyl alcohol, and the Tyzor TPT were added
to the reaction flask and the temperature was brought up to 200°C as
rapidly as possible. After the first staged add of PET and each
subsequent add the temperature was brought up to 250°C rapidly with the
rheostat set on 80% after a homogeneous and clear reaction mass was
achieved from the previous add. The reaction mass was held at 250°C for
an additional 30 minutes after the last add was clear and homogeneous.
The PET seemed to dissolve and react without difficulties.
[0077] The ethoxylated stearyl alcohol was added to assess whether some
termination with a longer chain aliphatic group would render the polymer
less tacky at room temperature. An ethoxylated C-18 alcohol was
selected to determine whether the ethoxylate group would add reactivity
and solubility to the reaction over the unmodified alcohol of Example 12.
The results of a clear melt and no apparent blooming of unreacted
material to the surface confirmed that the ethoxylated stearyl alcohol
added reactivity and solubility to the reaction. The polymer appeared to
have improved adhesion when poured hot onto a substrate, but
crystallized too rapidly and may not have been strong enough for some
coating applications. The viscosity was 2 Poise at 175°C.
Example 15:

[0078] The PEG 400, ethoxylated stearyl alcohol, trimethyolpropane, and the
Tyzor TPT were added to the reaction flask and the temperature was
brought up to 200°C as rapidly as possible. After the first staged add of
PET and each subsequent add the temperature was brought up to 250°C
rapidly with the rheostat set on 80% after a homogeneous and clear
reaction mass was achieved from the previous add. The reaction mass
was held at 250°C for an additional 30 minutes after the last add was clear
and homogeneous. The PET seemed to dissolve and react without
difficulties.
[0079] Adding the trimethylolpropane to the polymer of Example 13 improved the
strength and resilience of the polymer. The polymer appeared to exhibit
excellent adhesion when poured hot onto a substrate and was
approaching good film strength. Upon setting some crystallization
occurred. The viscosity was 5 Poise at 175°C.
Example 16:

[0080] The ethoxylated glycerine, ethoxylated stearyl alcohol, trimethylolpropane,
and the Tyzor TPT were added to the reaction flask and the temperature
was brought up to 200°C as rapidly as possible. After the first staged add
of PET and each subsequent add the temperature was brought up to
250°C rapidly with the rheostat set on 80% after a homogeneous and clear
reaction mass was achieved from the previous add. The reaction mass
was held at 250°C for an additional 30 minutes after the last add was clear
and homogeneous. A vacuum was pulled for 10 minutes. The PET
seemed to dissolve and react without difficulties.
[0081] The ethoxylated glycerine was added to provide additional branched sites
for strength characteristics through the increase of cross-link density,
when compared with the polymer prepared in accordance with Example
14. The results showed that this addition did provide a slight boost in
viscosity to 5 Poise at 175°C. The viscosity increase is believed to be
attributable to an increase in molecular weight. The polymer was tough
and resilient and slightly less crystalline than the polymer prepared in
accordance with Example 14. A 10-minute vacuum of 20 in Hg was
applied at 250°C and the viscosity was 12 Poise at 175°C. Compounds
were made using this polymer that proved to be suitable for hot melt
coating applications.
Example 17:

[0082] The reaction of Example 11 was repeated using no Tyzor TPT to catalyze
with. The polyethylene glycol with a molecular weight of 400 was added to
the reaction flask and the temperature was brought up to 200"C as rapidly
as possible. After the first staged add of PET and each subsequent add
the temperature was brought up to 270CC rapidly with the rheostat set on
80% after a homogeneous and clear reaction mass was achieved from the
previous add. The reaction mass was held at 270°C for an additional 30
minutes after the last add was clear and homogeneous.
[0083] This Example was conducted to assess whether the PET would
transesterify without a catalyst. The PET appeared to add in slower, and
consequently, the temperature was increased 20 °C, which appeared to
somewhat offset the absence of catalyst. Transesterification will occur
with some forms of PET even without additional catalyst.
[0084] Sizing Compositions — film forming polymers that can be dispersed or
dissolved in water are widely used for sizing textile fibers and paper
products. These polymers in many instances have to retain their solubility
because they are later removed.
Example 18:

[0085] The bis-diethylene glycol sulfo-isophthalate (sodium salt), the glycerine
ethoxylate, the trimethylolpropane, and the Tyzor TPT were added to the
reaction vessel and heated to 200°C. The PET was added in stages with
each stage brought up to 250°C before the next stage. After all the PET
was added the polymer was kept at 250°C for an additional 1 hour to
insure equilibrium and homogeneity of the polymer.
[0086] This reaction proceeded without problems. The polymer had an initial
viscosity of 3 poise at 175°C. A vacuum of 20 in Hg was applied for 10
minutes and the polymer's viscosity went to 12 Poise at 175°C. This resin
dispersed easily in hot water. The bis-diethylene glycol sulfosiophthalate,
sodium salt, was added to provide a water-soluble group to the polymer.
This polymer would make a suitable candidate for sizing compositions, ink
jet resins, and any film-forming compositions that require water
dispersibiiity.
[0087] Higher molecular weight fiber or film — In the production of fibers or films,
the viscosity, resiliency, or other properties of the molten resin should be
high enough to allow further processing with the molten material. With
many films, a certain degree of cross-link density is incorporated into the
polymer to achieve this. It becomes necessary at times to approach the
gellation point of the polymer in order to achieve these running properties.
With the process of the preferred embodiments, one skilled in the art can
approach the gellation point by selecting an appropriate cross-link density
in the modifying monomer mix, thereby achieving unheard of properties
with great accuracy. In fact, in many cases gellation is a desirable property
to achieve high strengths and cohesive properties. With this process, and
the proper choice of beginning multifunctional alcohols or esters, gellation
can be approached with large quantities of the commercially available
condensation polymer.
Example 19:


[0088] The PEG 400, ethoxylated stearyl alcohol, trimethylolpropane, and the
Tyzor TPT were added to the reaction flask and the temperature was
brought up to 200°C as rapidly as possible. After the first staged add of
PET and each subsequent add through add 7 the temperature was
brought up to 250°C. rapidly with the rheostat set on 80% after a
homogeneous and clear reaction mass was achieved from the previous
add. Prior to add 8 the temperature of the reaction mass was raised to
270°C to offset the increase in viscosity. After add 8 the reaction was
returned to 270°C. After Add 9 the reaction mass was brought up to
290°C and again back to 290°C after add 10 and 11. The reaction mass
was held at 250°C for an additional 1 hour after the last add was clear and
homogeneous.
[0089] It was difficult to stir such a small amount of modifying monomer mix with
any amount of PET. A kettle designed to agitate small amounts better
initially would be preferred. Therefore, the reactor utilized in this example
required small initial adds and careful attention. No more PET was added
because of the obvious viscosity increase that occurred with the last add
of PET. The final polymer had a melt viscosity of greater than 100 Poise at
200°C. but was still movable at higher temperatures. One could easily
draw out a fiber from the molten mass and continue to draw indefinitely.
This was a good film and fiber forming polymer.
[0090] Polyols — The process described herein also can be used for making a
variety of polyols. A polyol is generally a lower molecular weight material
containing terminating hydroxyl groups that can take part in other
reactions to form higher molecular weight materials. A common use for
these polyols is in making polyurethane. Polyurethane is a rigid, semi-
rigid, or flexible polymer that can be used to make a number of materials
such as adhesives, insulating foam, foam structural items like shoe
insoles, rubber-like structural items, and rigid structural items.
Example 20:

[0091] The polyol of Example 17 was further reacted according to the formula
above to produce a polyurethane foam. All the ingredients were mixed in
a cup. The polymethylene polyphenylpolyisocyanate was added last to
ensure good mixing. After a few minutes the reaction started and
produced a volume of foam. Once cooled the foam was rigid, tough, and
suitable for some structural foam applications.
Example 21:


[0092] The polyol of Example 4 was further reacted according to the formula
above to produce a polyurethane. All the ingredients were mixed in a
beaker after heating the polymer to 130 °C. The polymethylene
polyphenylpolyisocyanate was added last to ensure good mixing and
mixed as rapidly as possible.
[0093] The reaction was quite rapid and vigorous stirring was conducted to obtain
an adequate mixture of the the components before the reaction started.
Significant heat was produced. Once cooled, the polymer was extremely
tough and would be suitable for some molding applications. This is about
the maximum molecular weight polymer that could be mixed by hand. It
would be easy to produce an article with even less of the polymethylene
polyphenylpolyisocyanate and a higher molecular weight polymer if the
mixing was carried out in an extruder.
[0094] Film forming, acid-terminated, water-dispersible compositions or powder
coatings:
Example 22:
[0095] The polymer from Example 14 was further processed by melting and
pouring back into the reaction flask. Heating was continued until the
polymer was 180 degrees C. An additional 10% of trimellitic anhydride
was added to the 176.9 g. mass to get a final weight of 196.6 grams. The
reaction mass was brought back to 180°C and held for 1 hour.
[0096] The polymer produced from this further processing was higher in
molecular weight and had a finished viscosity of 15 Poise at 175°C. It had
a relatively high Tg and was easy to grind into a powder that could be
refused with heat. The powder also dispersed into 70°C hot water
containing 1 % ammonium hydroxide to make a 20% dispersion suitable as
a water dispersible coating composition. This polymer would make a
suitable candidate for sizing compositions, ink jet resins, and any film-
forming compositions that require water dispersibility. Due to its relatively
high glass transition temperature it also would make a good candidate for
an acid-terminated powder coating.
[0097] Film Compositions from Polyethylene Naphthalate (PEN) — PEN is a
relatively new polymer. Prior to the construction of a manufacturing site by
Amoco specifically for the manufacture of NDC, or dimethyl-2,6-
naphthalenedicarboxylate the intermediate for PEN, the cost of PEN was
prohibitive for all but the most demanding applications. Today, however,
many items of commerce utilize PEN.
[0098] There are advantages of using PEN over PET for packaging of certain
articles. For example, the barrier properties of PET are not believed to be
adequate for certain applications where barrier properties are desirable.
PET has been used for bottling beer, but because of the high permeability
of oxygen, it sometimes causes the flavor to deteriorate rapidly. There
have been several products where PET is laminated with a high oxygen
barrier film to try to compensate for this. PEN has the needed barrier
properties. This and the fact that it can take higher temperatures that are
used to pasteurize some liquids, it is expected that the use of PEN will
increase over the next decade.
[0099] The process of the embodiments described herein can make use of PEN
as the commercially available condensation polymer. The temperatures
usually required to use this process with PEN are greater than that of PET,
and typically are on the order of 250 to 280 °C.
Example 23:


[0100] The PEG 400, trimethylolpropane, and the Tyzor TPT were added to the
reaction flask and the temperature was brought up to 200°C as rapidly as
possible. After the first staged add of PEN the temperature was brought to
260°C and produced some amount of foam due to boiling of the monomer
mix. This subsided and with each subsequent add through add 8 the
temperature was brought up to 265°C rapidly with the rheostat set on 80%
after a homogeneous and clear reaction mass was achieved from the
previous add. After add 8 the reaction was returned to 280°C and held for
1 hour. This material seemed to behave similar to PET but required
higher temperatures for transesterification to occur rapidly. The finished
polymer was flexible and a good film forming material.
[0101] In the following examples, the process disclosed herein was performed in
a small reactor suitable for making enough material to compound and run
onto carpet.
Example 24:

[0102] The ethoxylated glycerine, the trimethylol propane, and the Tyzor TPT
were added to the reactor and the temperature was brought up to 430°F
as rapidly as possible. After the first staged add of PET the temperature
was brought up to 450°F, after the 2nd and 3rd add up to 460°F, after the
4th and 5th add up to 470°F, after the 6th add up to 475°F, after the 7th and
8th add up to 480F, and after the 9th and final add back up to 490° to 500°F
for 1 hour. All of the PET was added without difficulties.
[0103] The reaction went very similar to the lab reactions. The hot melt polymer
produced was further compounded into a backing material suitable for
carpet backing. The material was run and the carpet samples were tested
and found to be suitable for commercial applications.
Example 25:

[0104] The ethoxylated glycerine, trimethylol propane, ethoxylated stearyl
alcohol, and the Tyzor TPT were added to the reactor and the temperature
was brought up to 430°F as rapidly as possible. After the first staged add
of PET the temperature was brought up to 450°F, after the 2nd and 3rd
add up to 460°F, after the 4th and 5th add up to 470°F, after the 6th add up
to 475°F, after the 7th add up to 480°F and after the 8th and final add back
up to 490° to 500°F for 1 hour. All of the PET was added without
difficulties and produced a clear, homogeneous melt.
[0105] The hot melt polymer made from this example was further processed into
a compound and applied to the back of carpet. The finished product was
ideal for a carpet backing material with good properties of tuft bond,
flexibility, Velcro, etc. The polymer made above was sent to a laboratory
to run a GPC (gell permeation chromatography) for molecular weights.
The molecular weight was determined to be 12,579 with a polydispersity of
4.64.
[0106] The embodiments have been described with reference to particularly
preferred embodiments and examples. Those skilled in the art will
appreciate that various modifications may be made to the embodiments
without significantly departing from the spirit and scope thereof.
What is claimed is:
1. A method of making a polymer using a commercially available
condensation polyester as a raw material comprising:
selecting a modifying monomer mix, wherein the modifying
monomer mix comprises at least one monomer, wherein the at least one
monomer is a molecule comprising a hydroxyl or an ester, is capable of
participating in transesterification reactions, and has a molecular weight of
less than 1500, and wherein the modifying monomer mix does not
comprise components derived from the commercially available
condensation polyester; and
transesterifying the modifying monomer mix with a predetermined
amount of the commercially available condensation polyester, to produce
a final polymer.
2. The method of claim 1, wherein the commercially available
condensation polyester is polyethylene terephthalate.
3. The method of claim 1, wherein the commercially available
condensation polyester is polyethylene naphthalate.
4. The method of claim 1, wherein the at least one monomer
comprises an ester.
5. The method of claim 1, wherein the at least one monomer is
ethoxylated.
6. The method of claim 1, wherein the final polymer is a polyol.
7. The method of claim 6, further comprising reacting the polyol with
an isocyanate to produce a polyurethane.
8. The method of claim 1, wherein transesterifying further comprises
applying a vacuum..
9. The method of claim 1, further comprising reacting the final polymer
with an anhydride to produce an acid-terminated polymer.
10. A hot melt adhesive comprising the final polymer produced by the
method of claim 1.
11. A film forming coating comprising the final polymer produced by the
method of claim 1.
12. A powder coating resin or component of a fusible coating system
comprising the final polymer produced by the method of claim 1.
13. A flexible film comprising the final polymer produced by the method
of claim 1.
14. A water dispersible polymer for water borne coating formulations,
sizing formulations, and ink jet formulas comprising the final polymer
produced by the method of claim 1.
15. A method of making a polymer using a commercially available
condensation polyester as a raw material comprising:
selecting a modifying monomer mix, wherein the modifying
monomer mix does not comprise components derived from the
commercially available condensation polyester; and
transesterifying the modifying monomer mix with a predetermined
amount of the commercially available condensation polyester, wherein
transesterifying is carried out for a period of time of less than about 5
hours, and at a temperature of from about 200 °C to about 290 • C,
wherein the transesterification produces a final polymer.
16. The method of claim 15, wherein the commercially available
condensation polyester is polyethylene terephthalate.
17. The method of claim 15, wherein the commercially available
condensation polyester is polyethylene naphthalate.
18. The method of claim 15, wherein the at least one monomer
comprises an ester.
19. The method of claim 15, wherein the at least one monomer is
ethoxylated.
20. The method of claim 15, wherein the final polymer is a polyol.
21. The method of claim 20, further comprising reacting the polyol with
an isocyanate to produce a polyurethane.
22. The method of claim 15, further comprising applying a vacuum
during the step of transesterifying.
23. The method of claim 15, further comprising reacting the final
polymer with an anhydride to produce an acid-terminated polymer.
24. A hot melt adhesive comprising the final polymer produced by the
method of claim 15.
25. A film forming coating comprising the final polymer produced by the
method of claim 15.
26. A powder coating resin or component of a fusible coating system
comprising the final polymer produced by the method of claim 15.
27. A flexible film comprising the final polymer produced by the method
of claim 15.
28. A water dispersible polymer for water borne coating formulations,
sizing formulations, and ink jet formulas comprising the final polymer
produced by the method of claim 15.



Embodiments relate to a relatively rapid transesterification process including transesterifying condensation polymers
such as polyethylene terephthalate (PET), or other polyesters used in commerce, with a modifying monomer mix containing other
monomers to manufacture new polymers containing the pre-condensed moieties. The process preferably only involves transesterification as a reaction mechanism. The process preferably produces a rapid buildup of molecular weight and/or polymer uniformity
by the high temperature transesterification of the condensation polymer with the modifying monomer mixture. The process can be
performed in any suitable vessel including an extrusion line, and it has the advantage of greatly reduced cycle times over currently
used condensation polymer utilization processes such as the recycling of PET into other materials.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=3GpDTUr/3c9rRehzqfLvzw==&loc=wDBSZCsAt7zoiVrqcFJsRw==


Patent Number 271480
Indian Patent Application Number 3502/KOLNP/2009
PG Journal Number 09/2016
Publication Date 26-Feb-2016
Grant Date 23-Feb-2016
Date of Filing 08-Oct-2009
Name of Patentee BEAULIEU GROUP, LLC D/B/A BEAULIEU OF AMERICA
Applicant Address 1502 CORONET DRIVE, DALTON, GA 30722 UNITED STATES OF AMERICA
Inventors:
# Inventor's Name Inventor's Address
1 SALSMAN, ROBERT, KEITH 164 PHEASANT RUN, HOSCHTON, GA 30548 UNITED STATES OF AMERICA
PCT International Classification Number C08G 64/00
PCT International Application Number PCT/US2008/004079
PCT International Filing date 2008-03-28
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 11/693,185 2007-03-29 U.S.A.