Title of Invention

"UV-CURABLE AQUEOUS EMULSION, PREPARATION THEREOF AND SOLVENTLESS COATING COMPOSITION COMPRISING THE SAME"

Abstract ABSTRACT "UV-CURABLE AQUEOUS EMULSION, PREPARATION THEREOF AND SOLVENTLESS COATING COMPOSTION COMPRISING THE SAME" The present invention relates to a UV-curable aqueous coating composition is characterized by using a UV-curable aqueous emulsion obtained by urethane reaction with a mixture comprising a poly-carbonate polyol or polyester polyol; an isocyanate compound; a urethane-reactive carboxylic acid; a UV-curable acrylic oligomer having 2 to 9 functional acrylate groups; a UV- curable acrylic monomer; and a urethane-reactive acrylate without an organic solvent. The inventive aqueous composition provides good environmental acceptability and satisfactory film properties comparable to those of the prior oily UV-curable coating composition and thereofore, it is useful for coating various plastics.
Full Text Technical Field
The present invention relates to a UV-curable aqueous emulsion, a method for
preparing the same and a solventless coating composition comprising the same.
Background Art
There have been developed various UV-curable aqueous coating compositions for
plastics which contain no environmentally hazardous organic solvent. For example,
Gennan Patent No. 2936039 discloses a coating composition comprising a waterdispersible
urethane acrylate prepared using amino sulphonic acid-alkali metal or -
alkaline earth metal salt. However, this method provides a coating film having poor
water resistance due to the alkali metal ion present on the film surface.
U.S. Patent No. 4,287,039 discloses a method of dispersing a polyester urethane
acrylate by using a dispersant. However, the film produced by this dispersion method
shows poor water resistance, hardness, gloss due to the presence of moisture on the
film.
U.S. Patent Nos. 5,135,963, 6,011,078, 6,207,744, 6,335,397, 6,436,540, and
6,538,046 disclose curable polyurethane aqueous coating dispersions. The UV-curable
polyurethane aqueous coatmg dispersions disclosed in these patents are obtained by
using oligomers having larger molecular weights to ensure the stability of dispersion in
water, but films obtained by using these dispersions have lower crosslinking densities,
which does not fulfill plastic coating requirements.
Disdosure of Invention
Technical Problem
Accordingly, it is a primary object of the present invention to provide a UV-curable
aqueous coating composition having good environmental acceptability and satisfactory
plastic coating film properties comparable to those of an oil-based UV-curable coating
composition.
Technical Solution
In accordance with one aspect of the present invention, there is provided a UVb
curable aqueous emulsion comprising :
(a) a urethane reaction product of 1 to 10 % by weight of a polycarbonate polyol or
polyester polyol, 1 to 10 % by weight of an isocyanate compound, 0.1 to 5 % by
weight of a reactive carboxylic acid, 1 to 10 % by weight of a UV-curable acrylic
oligomer having 2 to 9 functional acrylate groups and 5 to 20 % by weight of a UVcurable
acrylic monomer; and
(b) 0.1 to 20 % by weight of a urethane-reactive acrylate, 0.01 to 1 % by weight of a
radical polymerization inhibitor and 55 to 75 % by weight of water, based on the total
weight of the UV-curable aqueous emulsion.
In accordance with one aspect of the present invention, there is provided a process
for preparing a UV-curable aqueous emulsion comprising :
(a) subjecting a mixture of 1 to 10 % by weight of a polycarbonate polyol or
polyester polyol, 1 to 10 % by weight of an isocyanate compound, 0.1 to 5 % by
weight of a reactive carboxylic acid, 1 to 10 % by weight of a UV-curable acrylic
oligomer having 2 to 9 functional acrylate groups and 5 to 20 % by weight of a UVcurable
acrylic monomer, based on the total weight of the UV-curable aqueous
emulsion, to a urethane reaction in the presence of a metallic catalyst;
(b) adding 0.1 to 20 % by weight of a urethane-reactive acrylate and 0.01 to 1 % by
weight of a radical polymerization inhibitor to the urethane reaction product obtained
in step (a); and
(c) neutralizing the mixture obtained in step (b) with a basic compound and adding
dropwise 55 to 75 % by weight of water thereto,
In accordance with still another aspect of the present invention, there is provided a
solventless UV-curable aqueous coating composition comprising (A) 90 to 99 % by
weight of the inventive UV-curable aqueous emulsion and (B) 1 to 10 % by weight of
a photoinitiator, based on the total weight of the composition.
Mode for the Invention

The inventive UV-curable aqueous emulsion is derived by subjecting a mixture of 1
to 10 % by weight of a polycarbonate polyol or polyester polyol, 1 to 10 % by weight
of an isocyanate compound, 0.1 to 5 % by weight of a reactive carboxylic acid, 1 to 10
% by weight of a UV-curable acrylic oligomer having 2 to 9 functional acrylate
groups, 5 to 20 % by weight of a UV-curable acrylic monomer, 0.1 to 20 % by weight
of a urethane-reactive acrylate and 0.01 to 1 % by weight of a radical polymerization
inhibitor to a urethane reaction, based on the total weight of the UV-curable aqueous
emulsion, in the presence of a metallic catalyst;
The method of preparing the UV-curable aqueous emulsion according to the present
invention is described in detail as follows:

The reaction is carried out until the content of the isocyanate(NCO%) measured by
the neutralization titration method is 2 to 5% by weight based on the product.
i) Polycarbonate polyol or polyester polyol
Representative examples of the polycarbonate polyol used in the present invention
include PCDL T4692 or PCDL T5651 (Asahi Kasei Co.).
The polyester polyol may include a polyester diol having 2 functional groups,
which can be conventionally obtained by mixing an excessive amount of a diol with a
dicarboxylic acid at a room temperature and subjecting the resulting mixture to an ester
condensation reaction in the presence of a metallic catalyst at 150 to 215 °C, preferably
about 210 °C for about 24 hours, until the acid value of the product as measured using
the neutralization titration method becomes 0.5 mg KOH/g or less. The diol may be
used in an amount of 1.2 to 1.7 eq. based on the 1 eq. of the dicarboxylic acid.
Representative examples of the diol used in manufachire of the polyester diol
include glycols having 2 to 15 carbon atoms such as neopentyl glycol, 1,4- butanediol,
1,6-hexanediol, diethyleneglycol, dipropyleneglycol, triethyleneglycol and tripropyleneglycol,
and preferably neopentyl glycol. Representative examples of the dicarboxylic
acid include maleic acid, maleic anhydride, fumaric acid, succinic acid,
glutamic acid, adipic acid, isophthalic acid, phtalic anhydride, crotonic acid, ataconic
acid, and a monoalkylester thereof, and preferably adipic aicd or isophthalic acid.
The polycarbonate polyol and polyester polyol preferably has a number-average
molecular weight of 1,000 to 3,000 g/mol and an OH value determined by back
titration of 50 to 2(M) mg KOH/g.
The polycarbonate polyol or polyester polyol is used in an amount of 1 to 10 %,
j
preferably 4 to 8 % by weight based on the total weight of the UV-curable aqueous
emulsion.
ii) Isocyanate compound
The isocyanate compound used in the present invention is preferably an aliphatic or
aromatic isocyanate having two or more hinctional isocyanate groups, and representative
examples thereof include 1,6-hexamethylene diisocyanate, isophorene diisocyanate,
1,4-cyclohexyl diisocyanate, 2,2,4-trimethyl hexamethylene diisocyanate
4
and tetramethylxylene diisocyanate.
The isocyanate compound is used in an amount of 1 to 10 %, preferably 3 to 7 % by
weight based on the total weight of the UV-curable aqueous emulsion. When the
amount of the isocyanate compound is larger than 10 % by weight, the cured coating
film becomes brittle due to an excessively high crosslinking density and suffers from
crack generation by heat or impact, and when less than 1 % by weight, mechanical
properties of the coating film become poor.
iii) Reactive carboxylic acid
Representative examples of the reactive carboxylic acid for introducing the hydrophilic
group to polyurethane acrylate include dimethylolpropanoic acid(DMPA),
dimethylolbutanoic acid(DMBA) and the like, and DMBA is preferred in order to keep
the viscosity low during the reaction.
The reactive carboxylic acid is used in an amount of 0.1 to 5 %, preferably 0.5 to 2
% by weight based on the total weight of the UV-curable aqueous emulsion. When the
amount of the reactive carboxylic acid is more than 5 % by weight, the solubility in
water increases resulting in the rise in the viscosity of an emulsion, and when less than
0.1 % by weight, an emulsion may not be formed or the storage stability deteriorates.
iv) UV-curable acrylic oligomer
In order to obtain satisfactory plastic coating film properties comparable to those of
the prior oil-based UV-curable coating composition, a UV-curable acrylic oligomer is
added and dispersed.
Representative examples of the UV-curable acylic oligomer used in the present
invention include urethane acrylate, polyurethane acrylate, ester acrylate, polyester
acrylate and a mixture thereof, having 2 to 9 functional aciylate groups, and commercially
available materials include, for example, EB-1290, EB-830 (commercially
available from SK-UCB, Korea) which have 6 functional acrylate groups and EB-
4883, EB-9260, EB-9384 (commercially available from SK-UCB, Korea) which have
3 functional acrylate groups. The oligomer is used in an amount ranging from 1 to 10
% by weight, preferably 6 to 9 % by weight based on the total weight of the UVcurable
aqueous emulsion.
The properties of the emulsion may be controlled by mixing a high functional
oligomer having 4 or more functional acrylate groups and a low functional oligomer
having 3 or less functional acrylate groups. The weight ratio of the low functional
oligomer : the high fiinctional oligomer may range from 1:0.5 to 1:3. When the ratio of
the high functional oligomer exceeds the upper limit, the cured coating film becomes
brittle due to an excessively high crosslinking density and suffers from crack
f
generation by heat or impact, and when it less than the lower limit, the chemical and
mechanical properties of the coating fibn become poor.
v) UV-curable acrylic monomer
The UV-curable acrylic monomer used in the present invention acts as a reactive
diluent instead of an organic solvent to control the curing rate and enhance the
adhesion, as well as to control the viscosity of the reactant.
The UV-curable acyUc monomer has no hydroxyl group and thus it is non-reactive.
Representative examples thereof include an acrylic acid ester of an aliphatic
polyhydric alcohol or alkoxy derivative thereof, for example trimethylolpropane
triacrylate(TMPTA), tripropyleneglycol diacrylate(TPGDA), 1,6-hexamethylenediol
diacrylate(HDDA), 1,4-butanediol diacrylate(l,4-BDDA), 1,3-isobutanediol diacrylate,
isobonyl acrylate(IBOA) or a mixture thereof.
The monomer is used in an amount ranging from 5 to 20 % by weight, preferably
12 to 16 % by weight based on the total weight of the UV-curable aqueous emulsion.
When the amount is more than 20 % by weight, the curing rate becomes low, and
mechanical and chemical properties of the coating film become poor, and when less
than 5 % by weight, the viscosity of the react become higher while UV-curable
emulsion becomes unstable.
In the present invention, the UV-curable acrylic monomer may be employed in an
amount ranging from 50 to 500 % by weight, based on the UV-curable acrylic
oligomer.
vi) Metallic catalyst
The reaction of preparing the UV-curable aqueous emulsion may be accelerated in
the presence of a metallic catalyst. Representative examples of the metallic catalyst
used in the reaction include a tin-based compound such as dibutyltin dilaurylate and an
amine compound such as DBU(l,8-diazabicyclo[5,4,0]undec-7-ene) and the like, and
the metallic catalyst may be used in a catalytically effective amount.

In step (b), the reaction is carried out at 70 to 90 °C until the isocynate peak at 2,260
cm' in a fourier transform infrared spectrom (FT-IR) disappears completely.
vii) Urethane-reactive acrylate
The urethane-reactive acrylate used in the present invention preferably has one or
more hydroxyl groups and 1 to 6 functional acrylate groups per molecule. Representative
examples of the urethane-reactive acrylate used in the present invention
7
include 2-hydroxyethyl acrylate(2-HEA), 2-hydroxypropyl acrylate(2-HPA),
caprolactone acrylate (Tone M-lOO, commercially available from U.C.C), a mixture of
pentaerythritol triacrylate and pentaerythritol tetraacrylate, a mixture of dipentaeiythritol
pentaacrylate and dipentaerythritol hexaacrylate and the like. Preferred are
a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate and a mixture
of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate. In each mixture,
the content of pentaerythritol triacrylate or dipentaerythritol tetraacrylate preferably
ranges from 50 to 60 % by weight.
The urethane- reactive acrylate is used in an amount ranging from 0.1 to 20 % by
weight, preferably 1 to 10 % by weight, based on the total weight of the UV-curable
aqueous emulsion.
viii) Radical polymerization inhibitor
Representative examples of the radical polymerization inhibitor used in the present
invention include hydroquinone, p-methoxyphenol, nitrobenzene,
BHT(2,6-di-tetra-butyl-4-methyIphenol) and the like.
The radical poljnnerization inhibitor is used in an amount ranging from 0.01 to 1 %
by weight, preferably 0.1 to 5 % by weight based on the total weight of the UV-curable
aqueous emulsion.

In order to enhance the aqueous dispersion stability, carboxyl groups in the
urethane-reaction product obtained in step (b) may be neutralized in part or as a whole
using a basic compound, and water is added dropwise thereto in an amount of 55 to 75
% by weight, based on the total weight of the UV-curable aqueous emulsion to obtain
an aqueous emulsion having a solid content of 25 to 45 % by weight.
Representative examples of the basic compound include organic or inorganic bases,
for example alkali or alkaline-earth metal hydroxide, oxide, carbonate or hydrogen
carbonate, and ammonia or primary, secondary or tertiary amine and the like,
preferably sodium hydroxide or tertiary amine such as triethylamine, triethanolamine,
dimethylethanolamine or diethylethanolamine. The basic compound used in the
reaction may be in the range of 0.8 to 1 eq. based on the carboxylic acid used.

The inventive UV-curable aqueous coating composition comprises (A) 90 to 99 %
by weight of a UV-curable aqueous emulsion prepared in accordance with the
inventive method and (B) 1 to 10 % by weight of a photoinitiator, based on the total
8-
weight of the composition
Representative examples of the photoinitiator which functions to generate radicals
by UV irradiation to initiate the crosslinking of unsaturated hydrocarbons include
1-hydroxyl cyclohexyl phenyl ketone(IRGACURE 184; conmiercially available from
Ciba Specialty Chemicals), bis(2,4,6-trimethyl benzoyl) phenyl phosphine
oxide(IRGACURE 819; commercially available from Ciba Specialty Chemicals),
2,4,6-trimethylbenzoyl diphenyl phosphine(TPO),
2-hydroxy-2-methyl-l-phenyl-l-propane(DARC)CUR 1173; commercially available
from cmA-GEIGY), IRGACURE 500, benzophenone(BP) and a mixture thereof, and
it is used in an amount ranging from 1 to 10 % by weight, preferably from 2 to 6 % by
weight based on the total weight of the composition.
In order to enhance the slip and gloss characteristics of the coating film, the
inventive coating composition may further comprise a leveling agent in an amount
ranging from 0.1 to 5% by weight based on the total weight of the composition, the
leveling agent being any of the conventional materials used in the coating composition,
preferably TEGO RAD 2200N(commercially available from Tego chemie Co.), BYK-
333, BYK-347, BYK-348 (commercially available from BYK chemie Co.), and a
mixture thereof.
In addition, so as to enhance the property of the coating film, the inventive coating
composition may further comprise additives such as XP-1045, XP-0596 and XP-0746
(nano-silica containing compound) (commercially available from hanse chemie Co.) in
an amount ranging from 0.1 to 2% by weight based on the total weight of the
composition.

In accordance with the present invention, the coating film may be prepared by spray
coating, dip coating, flow coating or spin coating the inventive coating composition on
the surface of a substrate to form a UV-curable fihn thereon, drying the coating layer at
room temperature and curing the dried layer by means of UV irradiation.
The inventive coating film may have a thickness ranging from 20 to 50 J
m
, and have improved properties in term of adhesion, pencil hardness, gloss and
moisture-, chemical-, abrasion- and acid-resistance.
As described above, the inventive UV-curable coating composition comprising the
inventive UV-curable aqueous emulsion having no organic solvent is capable of
providing a coating film having good environmental acceptability and satisfactory
properties comparable to those of the prior oil-based UV-curable coating composition.
Accordingly, it is useful as environmentally friendly plastic aqueous coating products.
1
The following Examples and Comparative Examples are given for the purpose of illustration
only and are not intended to limit the scope of the invention.

Preparation Example 1
535g of neopentyl glycol, 665g of adipic acid and 0.3g of dibutyl tin oxide were
added to a 4-neck round bottom flask, and the temperature was raised to 150°C under a
nitrogen atmosphere. After the condensation reaction started, the temperature was
maintained at 150°C for 1 hour, the reaction temperature was then raised to 210°C at a
rate of 5°Cymin, and at 210°C, 300 g of toluene was added thereto. The resulting
mixture was subjected to an azeotropic distillation until the acid value of the reaction
product became 0.5 mg KOH/g or less. After completion of the reaction, residual
toluene, water and unreacted starting materials were removed at 18G°C under a vacuum
to obtain a polyester diol having a number-average molecular weight of about 1,000 g/
mol calculated from the hydroxyl group value.
Preparation Example 2
The procedure of Preparation Example 1 was repeated except for using 550 g of
neopentyl glycol and a combination of 370g of adipic acid and 280g of isophthalic acid
as the dicarboxylic acid component, to obtain a polyester diol having a numberaverage
molecular weight of 2,000 g/mol.

Preparation Example 3
27g and 53g of polyester diols obtained in Preparation Example 1 and 2, respectively,
18g of dimethylolbutylic acid (DMBA) as a urethane-reactive carboxylic
acid, 64g of isophorene diisocyanate(IPDI), 80g of EB-1290(SK-UCB) as a UVcurable
acryUc oligomer, 70g of trimethylolpropane triacrylate(TMPTA) and 60g of
hexamethylene diaciylate(HDDA) as a UV-curable monomer were added to a 4-neck
round bottom flask while stirring. Then, O.lg of p-methoxyphenol(HQ-MME) as a
radical polymerization inhibitor and O.lg of dibutyltin dilaurylate(DBTDL) as a
reaction catalyst were added thereto, and the resulting mixture was stirred at 85°C.
When the content of isocyanate(NCO %) reached 2.2%, 17g of
2-hydroxyethylacrylate(2-HEA) as a urethane-reactive acrylate and O.lg of DBTDL as
a catalyst were successively added and the resulting mixture was reacted at 85°C until
I
#
the isocyanate peak on an FT-IR scan disappeared. The reaction mixture was cooled to
50°C and 1 Ig of triethylamine(TEA) was added dropwise thereto over 10 minutes, and
then the resulting mixture was kept at the same temperature for 1 hour to neutralize the
mixture. 600g of distilled water was then added thereto with vigorous agitating to
obtain a UV-curable aqueous emulsion containing a polyurethane acrylate dispersing
agent having 2 functional acrylate groups.
Preparation Eyamplc 4
The procedure of Preparation Example 3 was repeated except for using 40g of EB-
1290 and 40 g of EB-9260(SK-UCB) instead of 80g of EB-1290, and 80g of TMPTA
and 50g of HDDA instead of 70g of TMPTA and 60g of HDDA as the UV-curable
monomer component, to obtain a UV-curable aqueous emulsion containing a
polyurethane acrylate dispersing agent having 2 functional groups.
Prpipararinn F.Taniplft S
The procedure of Preparation Example 3 was repeated except for using 40g of EB-
1290 and 40 g of EB-9260 instead of 80g of EB-1290, and 70g of TMPTA, 40g of
HDDA and 35g of isobonyl acrylate(IBOA) instead of 70g of TMPTA and 60g of
HDDA, to obtain a UV-curable aqueous emulsion containing a polyurethane acrylate
dispersing agent having 2 functional groups.
Preparation Kyamplt;! tf
The procedure of Preparation Example 3 was repeated except for using 19g and 38g
of polyester diols obtained in Preparation Example 1 and 2, respectively, 46g of IPDI,
60g of TMPTA and 70g of HDDA as the UV-curable monomer component, 66g of a
mixture(l/l mole ratio) of pentaerythritol triacrylate and pentaerythritol tetraacrylate as
the urethane-reactive acrylate component, and 8g of TEA, to obtain a UV-curable
aqueous emulsion containing a polyurethane acrylate dispersing agent having 6
functional groups.
Preparation Eyamplft 7
The procedure of Preparation Example 6 was repeated except for using 40g of EB-
1290 and 40g of EB-9260 as the UV-curable oUgomer, and 60g of TMPTA and 60g of
HDDA as the UV-curable monomer component, to obtain a UV-curable aqueous
emulsion containing a polyurethane acrylate dispersing agent having 6 functional
groups.
Preparation ETamplc 8
II
The procedure of Preparation Example 6 was repeated except for using 30g of EB-
1290 and 30g of EB-9260 as the UV-curable oUgomer, and 60g of TMPTA, 50g of
HDDA and 50g of IBOA as a UV-curable monomer, to obtain a UV-curable aqueous
emulsion containing a polyurethane acrylate dispersing agent having 6 functional
groups
Preparation Kyample 9
The procedure of Preparation Example 6 was repeated except for using 15g and 31g
of polyester diols obtained in Preparation Example 1 and 2, respectively, lOg of
dimethylolbutylic acid (DMBA), 37g of IPDI, and 90g of a mixture of dipentaerythritol
pentaacrylate and dipentaerythritol hexaacrylate as the urethane-reactive
acrylate component to obtain a UV-curable aqueous emulsion containing a
pol3narethane acrylate dispersing agent having 10 functional groups.
PreparatioD FTampla in
The procedure of Preparation Example 9 was repeated except for using 30g of EB-
1290 and 40g of EB-9260 as the UV-curable oUgomer, and 60g of TMPTA and 70g of
j
HDDA as the UV-curable monomer, to obtain a UV-curable aqueous emulsion
containing a polyurethane acrylate dispersing agent having 10 functional groups.
Preparatinn F.Tample 11
The procedure of Preparation Example 9 was repeated except for using 30g of EB-
1290 and 40g of EB-9260 as the UV-curable oligomer, and 50g of TMPTA, 50g of
HDDA and 50g of IBOA as the UV-curable monomer, to obtain a UV-curable aqueous
emulsion containing a polyurethane acrylate dispersing agent having 10 functional
groups,

F.^amplcs 1 tn 9
95g of the UV-curable aqueous emulsion obtained in Preparation Example 3,3%
by weight of DAROCUR 1173 (CIBA-GEIGY) as a photoinitiator and 1.4 % by
weight of BYK-333 and 0.6 % by weight of BYK-347(BYK chemie) as a leveling
agent were mixed, and the resulting mixture was stirred for 30 minutes to obtain a
solventless UV-curable coating composition (Example 1).
A similar procedure was repeated using each of the UV-curable aqueous emulsion
obtained in Preparation Examples 4 to 11, to obtain eight solventless UV-curable
12-
i
coating compositions (Examples 2-9).
ComparaHvg F.^aniplf 1
In accordance with the composition of a conventional UV-curable coating
composition, 15 % by weight of EB 1290,11 % by EB 9260, 6 % by weight of
trimethylolpropane triacrylate and 7 % by weight of methylenediol diacrylate were
added to a mixture of 30 % by weight of toluene, 15 % by weight of methyl isobutyl
ketone, 5 % by weight of ethyl acetate and 5 % by weight of ethyl cellosolve while
stirring. Then, 5 % by weight of DAROCUR 1173 as a photoinitiator and 1 % by
weight of BYK-333(BYK chemie) as a leveling agent were added thereto, and the
resulting mixture was stirred for 30 min to obtain a UV-curable coating
composition(non-volatile content, 45%).

F.TamplR^ i n f i l l s
Each of the UV-curable coating compositions obtained in Examples 1 to 9 was
coated on a polycarbonate substrate coated witii a UVP-9500SI(S) (SSCP Co., Ltd) by
spray coating, the resulting coating was dried at 60°C for 5 min, and cured twice at a
line speed of 10/min under a light intensity of 380 mJ/cm with a Fusion Lamp(Fusion
System Co.), to obtain a total of nine coating films.
Comparatf vg F.yanipli;i 2
The procedure of Examples 10 to 18 was repeated except for using the UV-curable
coating composition obtained in Comparative Example 1 and drying at 60°C for 1 or 2
min to remove the organic solvent to obtaine a coating fihn.

The physical and chemical characteristics of the coating films obtained in
Examples 10 to 18 and Comparative Example 2 were evaluated in accordance with the
following methods.
(1) Adhesion Property : ASTM D3359-87
A coating film was cut in a checkered pattern at 1mm intervals to form 100 1mm x
Irnm squares. An adhesive test tape was firmly attached to the formed pattern and
removed with a sharp peeling motion, which was repeated three times. The state of the
pattern was examined and the results were evaluated according to the following
)3
criteria:
5B : no peeling at the cut edge or within the patterned area
4B : slight peeling at the cut edge and peeling of less than 5% of the patterned area
3B : some peeling and breakage at the cut edge and peeling less than 15% of the
patterned area
(2) Pencil Hardness : ASTM D3363-74
A test coating film was scratched with a pencil of varying hardness under a
constant pressure at an angle of 45 degrees, which was repeated five times. The
hardness value of the pencil produced only one scratch or breakage of the coating layer
is referred to as the pencil hardness.
(3) Gloss
The gloss value of a test coating film was measured at light acceptance and incident
angles of 60 degrees with a B YK-GARDNER glossmeter, and the result obtained was
expressed as a percentage value based on the gloss value of the base plane of 100.
(4) Abrasion resistance
The surface of a test coating film was rubbed with an eraser under a 500g-load at a
rate of 40 times/min until the substrate surface became visible with the naked eye, and
the abrasion resistance was expressed in terms of the number of rubbing.
© ; 2,000 times or more, O ; 1,700 to 2,000 times or more
(5) Chemical resistance
The surface of a test coating film was dipped in 99.3% methanol, followed by
rubbing with an eraser under a 500g-load at a rate of 40 times/min until the substrate
surface became visible with the naked eye, and the chemical resistance was expressed
in terms of the number of rubbing.
®; 300 times or more, O ; 260 to 300 times or more
(6) Moisture resistance
The degree of deformation and the state of adhesion were evaluated after exposing a
test coating film to a condition of 50 °C and 95% relative humidity for 72 hours.
j
® ; excellent, O ; good
(7) Acid resistance
The degree of defonnation and the state of adhesion were evaluated after treating a
test coating film with a standard pH 4.6 solution for 72 hours.
® ; excellent, O; good
(8)UVtest(QUV)
The degree of defonnation and the state of adhesion property were evaluated after
keeping a test coating film for 72 hours with a UV tester(QUV, Q-Pannel).
The physical properties of the coating films thus measured are showed in Table 1.
Table 1
I
-S "
e a *^
J^ _^ I
Id
a
t » I l l s
g. I I, I I -2 .§ B
5 "- 5 a i
As shown in Table 1, the coating fibns obtained using the inventive coating compositions
exhibit equal or better properties in terms of adhesion property, pencil
hardness, gloss, abrasion resistance, chemical resistance, moisture resistance and acid
resistance, as compared to those obtained using conventional compositions while the
inventive coating film are generated without any environmental hazard.
While the invention has been described with respect to the above specific embodiments,
it should be recognized that various modifications and changes may be
made to the invention by those skilled in the art which also fall within the scope of the
invention as defined by the appended claims.









We Claim
1. A UV-curable aqueous emulsion comprising:
(a) a urethane reaction product of
1 to 10 % by weight of a polycarbonate polyol or polyester polyol,
1 to 10 % by weight of an isocyanate compound,
0.1 to 5 % by weight of a reactive carboxylic acid,
1 to 10 % by weight of a UV-curable acrylic oligomer having 2 to 9 functional
acrylate groups and, wherein the UV-curable acrylic oligomer is selected from the
group consisting of urethane acrylate, polyurethane acrylate, ester acrylate, polyester
acrylate and a mixture thereof, and wherein the UV-curable acrylic
oligomer is a mixture of an oligomer having 4 or more functional acrylate groups and
an oligomer having 3 or less functional acrylate groups,
5 to 20 % by weight of a UV-curable acrylic monomer selected from the group
consisting of trimethylolpropane triacrylate (TMPTA), tripropyleneglycol diacrylate
(TPGDA), 1,6-hexamethylenediol diacrylate (HDDA), 1,4-butanediol diacrylate (1,4-
BDDA), 1,3-isobutanediol diacrylate, isobonyl acrylate (IBOA) and a mixture
thereof; and
0.01 to 1 % by weight of a radical polymerization inhibitor and
55 to 75 % by weight of water,
based on the total weight of the UV-curable aqueous emulsion.
2. The UV-curable aqueous emulsion as claimed in claim 1, wherein the polycarbonate
polyol or polyester polyol has a number-average molecular weight of 1,000 to 3,000 g/
mol and an OH value of 50 to 200 mg KOH/g.
3. The UV-curable aqueous emulsion as claimed in claim 1, wherein the reactive carboxylic
acid is dimethylolpropanoic acid (DMPA) or dimethylolbutanoic acid (DMBA).
4. The UV-curable aqueous emulsion as claimed in claim 1, wherein the oligomer having 3
or less functional acrylate groups is mixed with the oligomer having 4 or more functional
arylate groups in a weight ratio of 1:0.5 to 1:3.
n
5. The UV-curable aqueous emulsion as claimed in claim 1, wherein the UV-curable acrylic
monomer is in an amount ranging from 50 to 500% by weight, based on UV-curable
acrylic oligomer.
6. The UV-curable aqueous emulsion as claimed in claim 1, wherein the urethane-reactive
acrylate is 2-hydroxyethyl acrylate(2-HEA), 2-hydroxypropyl acrylate(2-HPA),
caprolactone acrylate, a mixture of pentaerythritol triacrylate and pentaerythritol
tetraaciylate, or a mixture of dipentaerythritol pentaaciylate and dipentaerythritol
hexaacrylate.
7. A process for preparing a UV-curable aqueous emulsion comprising:
(a) subjecting a mixture of 1 to 10 % by weight of a polycarbonate polyol or polyester
polyol, 1 to 10 % by weight of an isocyanate compound, 0.1 to 5 % by weight of a
reactive carboxylic acid, 1 to 10 % by weight of a UV-curable acrylic oligomer having 2
to 9 functional acrylate groups wherein the UV-curable acrylic oligomer is selected from
the group consisting of urethane acrylate, polyurethane acrylate, ester acrylate, polyester
acrylate and a mixture thereof, and wherein the UV-curable acrylic oligomer is a mixture
of an oligomer having 4 or more functional acrylate groups and an oligomer having 3 or
less functional acrylate groups, and 5 to 20 % by weight of a UV-curable acrylic
monomer selected from the group consisting of trimethylolpropane triacrylate (TMPTA),
tripropyleneglycol diacrylate (TPGDA), 1,6-hexamethylenediol diacrylate (HDDA), 1,4-
butanediol diacrylate (1,4-BDDA), 1,3-isobutanediol diacrylate, isobonyl acrylate (IBOA)
and a mixture thereof, based on the total weight of the UV-curable aqueous emulsion, to
a urethane reaction in the presence of a metallic catalyst; or an amine compound;
(b) adding 0.1 to 20 % by weight of a urethane-reactive acrylate and 0.01 to 1 % by
weight of a radical polymerization inhibitor to the urethane reaction product obtained in
step (a); and
(c) neutralizing the mixture obtained in step (b) with a basic compound and adding
dropwise 55 to 75 % by weight of water thereto.
8. The process as claimed in claim 7, wherein the reaction in step (a) is carried out until the
content of the isocyanate (NCO %) become 2 to 5 % by weight based on the product.
9. The process as claimed in claim 7, wherein the basic compound is selected from the
group consisting of alkali or alkaline-earth metal hydroxide, oxide, carbonate or
hydrogen carbonate, and ammonia or primary, secondary or tertiary amine.
10. The process as claimed in claim 7, wherein the metallic catalyst is a tin-based
compound.
11. A UV-curable aqueous coating composition comprising (A) 90 to 99 % by
weight of a UV-curable aqueous emulsion as claimed in claim 1 and (B) 1 to 10 % by
weight of a photoinitiator, based on the total weight of the composition.
12. A plastic article having a cured coating film of the coating composition
as claimed in claim 11.
Dated this 12"^ day of August, 2008 ^ OT^^^ ^^^^^—_ _
ANUPAM TRIVEDI
OF K & S PARTNERS
ATTORNEY FOR THE APPLICANT(S)

;

Documents:

6921-delnp-2008-Abstract-(19-08-2013).pdf

6921-delnp-2008-abstract.pdf

6921-DELNP-2008-Assignment-(01-12-2011).pdf

6921-delnp-2008-Assignment-(29-03-2012).pdf

6921-delnp-2008-assignment.pdf

6921-delnp-2008-claims.pdf

6921-DELNP-2008-Correspondence Others-(01-12-2011).pdf

6921-delnp-2008-Correspondence Others-(06-12-2013).pdf

6921-DELNP-2008-Correspondence Others-(16-02-2012).pdf

6921-delnp-2008-Correspondence Others-(17-07-2014).pdf

6921-delnp-2008-Correspondence Others-(26-09-2013).pdf

6921-delnp-2008-Correspondence Others-(29-03-2012).pdf

6921-delnp-2008-Correspondence-Others-(08-07-2013).pdf

6921-delnp-2008-Correspondence-Others-(19-08-2013).pdf

6921-delnp-2008-correspondence-others.pdf

6921-delnp-2008-Description (Complete)-(19-08-2013).pdf

6921-delnp-2008-description (complete).pdf

6921-DELNP-2008-Form-1-(01-12-2011).pdf

6921-delnp-2008-Form-1-(29-03-2012).pdf

6921-delnp-2008-form-1.pdf

6921-DELNP-2008-Form-2-(01-12-2011).pdf

6921-delnp-2008-Form-2-(19-08-2013).pdf

6921-delnp-2008-Form-2-(29-03-2012).pdf

6921-delnp-2008-form-2.pdf

6921-delnp-2008-Form-3-(06-12-2013).pdf

6921-delnp-2008-Form-3-(08-07-2013).pdf

6921-delnp-2008-form-3.pdf

6921-delnp-2008-form-6.pdf

6921-DELNP-2008-GPA-(01-12-2011).pdf

6921-delnp-2008-GPA-(29-03-2012).pdf

6921-delnp-2008-pct-101.pdf

6921-delnp-2008-pct-210.pdf

6921-delnp-2008-pct-237.pdf

6921-delnp-2008-pct-304.pdf

6921-delnp-2008-pct-308.pdf

6921-delnp-2008-Petition-137-(19-08-2013).pdf


Patent Number 266029
Indian Patent Application Number 6921/DELNP/2008
PG Journal Number 14/2015
Publication Date 03-Apr-2015
Grant Date 27-Mar-2015
Date of Filing 12-Aug-2008
Name of Patentee AKZO NOBEL INDUSTRIAL COATING INTERNATIONAL B.V.
Applicant Address Velperweg 76,NL-6824 BM Amhem, The Netherlands
Inventors:
# Inventor's Name Inventor's Address
1 KIM, DONG SOO GGOTMOENOEULMAEUL SINAN APT., 241-1205, #883-6, JEONGJA 2-DONG, JANGAN-GU, SUWON-SI, GYEONGGI-DO 440-302, REPUBLIC OF KOREA
2 JEONG, TAE YUN WHITEVIL 205, #1172-2, SA-DONG, SANGROK-GU, ANSAN-SI, GYEONGGI-DO 426-170, REPUBLIC OF KOREA
3 HONG, SU DONG UREUKJUGONG APT.,707-1401, # 1146-11, SANBON-DONG, GUNPO-SI, GYEONGGI-DO 435-040, REPUBLIC OF KOREA
4 OH, JUNG-HYUN DONGBUSTARVILLA 403, #1503-7, JUNG-DONG, HAEUNDAE-GU, BUSAN 612-010, REPUBLIC OF KOREA
PCT International Classification Number C09D 175/04
PCT International Application Number PCT/KR2007/000245
PCT International Filing date 2007-01-15
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10-2006-0003743 2006-01-13 Republic of Korea