JP3035402B2 - Abrasion resistant UV curable coating composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abrasion-resistant ultraviolet-curable coating composition which forms a coating film having excellent abrasion resistance by being applied to a plastic substrate and cured. More specifically, the present invention relates to an abrasion-resistant ultraviolet-curable coating composition that forms a coating film having excellent adhesion to a plastic substrate, transparency, and abrasion resistance.

[0002]

2. Description of the Related Art Generally, plastic products,
For example, polycarbonate, polymethyl methacrylate, polyethylene terephthalate, ABS resin and the like are used in various applications because of their excellent light weight, easy processability, impact resistance and the like. However, these plastic products have a drawback that they are easily scratched due to their low surface hardness and significantly impair the original transparency or appearance of the resin. It is difficult. Various hard coating agents such as an acrylic hard coating agent and a silicon hard coating agent have been proposed as coating materials that impart abrasion resistance to such a plastic substrate and increase the surface hardness. Among these hard coat agents, acrylic hard coat agents are characterized by short curing time and excellent productivity due to ultraviolet curing, but have the disadvantage of inferior abrasion resistance compared to silicon hard coat agents. Was. In order to improve the abrasion resistance of this acrylic hard coat agent, publication 57-57,984 discloses an ultraviolet curable coating obtained by adding a hydrolyzate of a hydrophilic silica sol and an acryloxy-functional or glycidoxy-functional silane compound to acrylate. A composition is disclosed. However, since the colloidal silica used in the present invention is a water-dispersed type, there is a limitation that acrylate, which has good miscibility with water, must be used for acrylate, and sufficient abrasion resistance is still not obtained. Not obtained. In order to avoid this drawback, JP-A-59-204669 discloses an abrasion-resistant coating obtained by adding a hydrophobic silica sol using an organic solvent as a dispersion medium to a polyfunctional acrylate and a hydrolyzate of a silane compound having an unsaturated group. A composition for a membrane is disclosed. Since a hydrophobic silica sol using an organic solvent as a dispersion medium is used as the silica sol in the coating composition, the selection range of usable polyfunctional acrylates is expanded, and the hardness is further improved.
However, the silane compound having an unsaturated group used in the composition is, for example, a monofunctional (meth) such as 3- (meth) acryloxypropyltrimethoxysilane.
Because it is an acryloyl compound, when it is blended with a polyfunctional acrylate, the acryloyl group density decreases from the viewpoint of the whole composition, and as a result, the crosslink density at the time of ultraviolet curing is unavoidable, and is still comparable to silicon-based hard coat agents Abrasion resistance could not be obtained. The present invention solves the conventional problems as described above, and adherence to a plastic substrate,
An object of the present invention is to provide an abrasion-resistant ultraviolet-curable coating composition that forms a coating film having excellent transparency and abrasion resistance.

[0003]

As a result of intensive studies, the present inventors have been able to solve the above-mentioned conventional problems. That is, the present invention provides (a) a compound obtained by reacting an epoxy group-containing silane coupling agent with a reaction product of a hydroxyl group-containing polyfunctional acrylate having a hydroxyl group and three or more acryloyl groups in a molecule and an acid anhydride, Abrasion-resistant UV-curable coating comprising (b) a polyfunctional acrylate having three or more acryloyl groups in a molecule, (c) a silica sol using an organic solvent as a dispersion medium, and (d) a photopolymerization initiator. The present invention provides a composition, and can form a coating film having excellent adhesion to a plastic substrate, transparency, and abrasion resistance.

Hereinafter, the present invention will be described in more detail. (Component (a)) The present invention is obtained by reacting a reaction product of a hydroxyl group-containing polyfunctional acrylate having a hydroxyl group and three or more acryloyl groups in a molecule and an acid anhydride with an epoxy group-containing silane coupling agent. One feature is the use of a compound. Since this compound has three or more acryloyl groups in the molecule, even when mixed with the polyfunctional acrylate as the component (b), there is almost no decrease in the acryloyl group density. It reacts with silanol groups present on the particle surface of the silica sol as component (c). High wear resistance can be realized by both effects. Examples of the hydroxyl group-containing polyfunctional acrylate having a hydroxyl group and three or more acryloyl groups in a molecule (hereinafter, simply referred to as hydroxyl group-containing polyfunctional acrylate) include pentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, and These mixtures and the like can be mentioned. Next, as the acid anhydride, succinic anhydride, dodecenylsuccinic anhydride, glutaric anhydride, maleic anhydride, citraconic anhydride, itaconic anhydride, phthalic anhydride, tetramethylene maleic anhydride, tetrahydrophthalic anhydride, 4-hydrophthalic anhydride,
Methyl-1,2,3,6 tetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendmethylenetetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, trimellitic anhydride, cyclopentanetetracarboxylic acid Acid dianhydrides, and mixtures thereof. The reaction between the hydroxyl group-containing polyfunctional acrylate and the acid anhydride is carried out by mixing the respective compounds at a ratio of -COOCO-group / -OH group ≤ 1,
It is performed by stirring at ~ 110 ° C for 1-8 hours.
Next, as an epoxy group-containing silane coupling agent,
3-glycidoxypropyltrimethoxysilane, 2-glycidoxyethyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-glycidoxyethyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-glycidoxyethylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-glycidoxyethylmethyldiethoxysilane, 3- (3,4-epoxycyclohexyl) propyltrimethoxysilane, 2- ( 3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3- (3,3
4-epoxycyclohexyl) propyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, and the like. A compound obtained by reacting a hydroxyl group-containing polyfunctional acrylate with an acid anhydride,
The reaction with the epoxy group-containing silane coupling agent is carried out by mixing at a ratio of epoxy group / —COOH group ≦ 1;
It is performed by stirring at 0 ° C. for 1 to 20 hours. The reaction between a hydroxyl group-containing polyfunctional acrylate and an acid anhydride, and the reaction between a compound obtained by reacting a hydroxyl group-containing polyfunctional acrylate with an acid anhydride and an epoxy group-containing silane coupling agent include, for example, methyl ethyl ketone and methyl isobutyl ketone. In the presence of an organic solvent such as, cyclohexanone, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, ethyl acetate, propyl acetate, butyl acetate, toluene, xylene, or three or more acryloyl molecules in the molecule (b). It can be carried out in the presence of a polyfunctional acrylate having a group. Further, in order to promote the reaction, for example, a catalyst such as benzyldimethylamine, triethylamine, tributylamine, triethylenediamine, benzyltrimethylammonium chloride, benzyltrimethylammonium bromide, tetramethylammonium bromide, cetyltrimethylammonium bromide, triphenylstibine and the like. Can be used. The amount used is 0.1 to 5% by weight, particularly preferably 0.2% by weight, based on the reaction raw material mixture (excluding the reaction solvent).
~ 2% by weight. In order to prevent polymerization due to an acryloyl group during the reaction, for example, hydroquinone, hydroquinone monomethyl ether, catechol, pt
It is preferable to use a polymerization inhibitor such as -butyl catechol, phenothiazine, etc., in an amount of 0.01 to 1% by weight, particularly preferably 0.05 to 0% by weight, based on the reaction raw material mixture (excluding the reaction solvent). 0.5% by weight.

(Component (b)) Next, polyfunctional acrylates having three or more acryloyl groups in the molecule include:
Trimethylolpropane triacrylate, EO-modified trimethylolpropane triacrylate, PO-modified trimethylolpropane triacrylate, trimethylolpropane tetraacrylate, tris (acryloxyethyl) isocyanurate, caprolactone-modified tris (acryloxyethyl) isocyanurate, pentaerythritol Triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, alkyl-modified dipentaerythritol acrylate, alkyl-modified dipentaerythritol tetraacrylate, alkyl-modified dipentaerythritol pentaacrylate, caprolactone-modified dipentaerythritol hexaacrylate , And mixtures of two or more of these and the like. Among these, dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, and mixtures thereof are particularly desirable from the viewpoint of abrasion resistance. The amount of the components (a) and (b) used is preferably (a) / (b) = 0.1 to 10 (weight ratio) from the viewpoint of the abrasion resistance of the resulting ultraviolet-cured coating film.

(Component (c)) Next, silica sol using an organic solvent as a dispersion medium includes silica having a particle diameter of 5 to 30 nm.
Solids having a solid content of 10 to 40%, and a dispersion medium of methyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, ethylene glycol, ethyl cellosolve, dimethylacetamide, a mixed solvent of xylene and n-butyl alcohol, and the like can be given. . Among them, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, ethyl cellosolve, silica sol using a mixed solvent of xylene and n-butyl alcohol is used to form a hydroxyl group-containing polyfunctional acrylate (a) component and an acid anhydride. Good compatibility with a compound obtained by reacting an epoxy group-containing silane coupling agent with a reactant, and a polyfunctional acrylate having at least three acryloyl groups in a molecule as component (b), resulting in a coating film obtained It is particularly desirable in terms of transparency. The amount of silica sol in which an organic solvent is used as a dispersion medium is as follows: solid content of silica sol / ａ (a)
Component + (b) component｝ (weight ratio) is preferably 0.1 to 5. When the weight ratio is less than 0.1, almost no improvement in wear resistance due to the silica sol is recognized. On the other hand, when the weight ratio exceeds 5, the crosslink density due to the acryloyl group decreases, and the abrasion resistance decreases.

(Component (d)) Next, as a photopolymerization initiator, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, diethoxyacetophenone, benzyl dimethyl ketal, 2-hydroxy-2-methylpro Piophenone, 1-hydroxycyclohexylphenyl ketone, benzophenone, 2,4,6-trimethylbenzoindiphenylphosphine oxide, 2-methyl- [4
-(Methylthio) phenyl] -2-morpholino-1-
Propanone, 2-benzyl-2-dimethylamino-1-
(4-morpholinophenyl) -butan-1-one, Michler's ketone, isoamyl N, N-dimethylaminobenzoate, 2-chlorothioxanthone, 2,4-diethylthioxanthone, and the like. These photopolymerization initiators include Two or more of them can be used in combination as appropriate. The photopolymerization initiator is used in an amount of 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the total of the components (a) and (b).

The composition of the present invention contains an ultraviolet absorber (for example, benzotriazole,
Benzophenone-based, salicylic acid-based, cyanoacrylate-based ultraviolet absorbers), ultraviolet stabilizers (eg, hindered amine-based ultraviolet stabilizers), antioxidants (eg, phenolic, sulfur-based, phosphorus-based antioxidants), antiblocking agents, Various additives such as a slip agent and a leveling agent which are compounded in such a composition can be compounded. Further, for the purpose of adjusting the viscosity, an organic solvent (for example, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone,
Ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, ethyl acetate, propyl acetate, butyl acetate, toluene, xylene, etc.) can also be added.

The composition of the present invention can be applied to a plastic substrate such as polycarbonate, polymethyl methacrylate, polyethylene terephthalate and ABS resin by dipping, flow coating, spraying, bar coating, gravure coating and roll coating. , Blade coating, air knife coating, etc., under a condition that a hard coat layer of 1 to 50 μm, preferably 3 to 20 μm is obtained on the surface of the plastic substrate after solvent drying and UV irradiation. Will be constructed. The composition of the present invention can be cured by using a lamp such as a xenon lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a carbon arc lamp, and a tungsten lamp.
The irradiation is performed for 2 seconds.

[0010]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the examples, parts and% mean parts by weight and% by weight, respectively. Example 1 (Preparation of component (a)) A mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate containing 67 mol% of dipentaerythritol pentaacrylate (manufactured by Nippon Kayaku Co., Ltd .: Kayarad DP)
HA, hydroxyl value 69 mgKOH / g) and succinic anhydride
Take 163 g and 10 g flasks each so that -COOCO- group / -OH group = 0.5, and further add toluene 49
g and hydroquinone monomethyl ether (0.17 g) were added and reacted at 110 ° C. for 3 hours. The acid value of the reaction product is 27mg
KOH / g. Then, 23.6 g of 3-glycidoxypropyltrimethoxysilane and 2 g of tetramethylammonium bromide were added thereto,
After reacting for 0 hours, the acid value became 2 mgKOH / g. As a result, a reaction product of dipentaerythritol pentaacrylate and succinic anhydride and 3-glycidoxypropyltrimethoxysilane (compound A) is
Prepared in dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, and toluene. The obtained composition (I) was prepared by mixing Compound A, dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, and toluene
34% and 21%, respectively, of the total weight of the composition (I)
%, 25% and 20%. (Preparation of abrasion-resistant ultraviolet curable coating composition) 50 parts of composition (I), silica sol using xylene and n-butyl alcohol as a dispersion medium (Nissan Chemical Industries: XBA-ST, solid content 30%, xylene 45) %, N-butyl alcohol 2
(5%) 133 parts and benzyldimethyl ketal 2 parts were mixed to obtain an abrasion-resistant ultraviolet-curable coating composition. The abrasion-resistant UV-curable coating composition was applied to a transparent 2 mm-thick polycarbonate plate using a bar coater so that the coating thickness after drying was 10 μm, and was heated and dried at 100 ° C. for 10 minutes. Using a high-pressure mercury lamp (emission length: 62.5 cm) with an output of 7.5 kw and an output density of 120 w / cm installed vertically to the sample passing direction, ultraviolet light was emitted at a position of 10 cm below the light source and at a conveyor speed of 2 m / min. And cured by ultraviolet light. The adhesion of the hard coat layer formed on the polycarbonate plate to the polycarbonate plate was evaluated by making 100 cross-cuts at 1 mm intervals on the hard coat layer with a cutter knife and compressing and strongly peeling Nichiban cellophane tape. / 100, good adhesion was obtained (cross-cut tape method JIS K5400). Further, the transparency of the obtained hard coat-treated polycarbonate plate was evaluated by cloudiness value (%) and found to be 0.6%, indicating that the transparency was good. The cloudiness value of the 2 mm thick polycarbonate plate before the hard coat treatment was 0.5% (cloudiness value = Td / Tt × 100 Td: scattered light transmittance, T
t: Total light transmittance JISK7105). Next, abrasion resistance was measured by using a wear wheel of CS-10F manufactured by Calibrase Co., Ltd. under a load of 500 g for 100 revolutions of Taber abrasion test. The difference between the cloudiness value after the Taber abrasion test and the cloudiness value before the Taber abrasion test was ΔH. Was 0.8%, and the abrasion resistance was good. The same Taber abrasion test was performed on a 2 mm-thick polycarbonate plate not subjected to the hard coat treatment, and the obtained ΔH was 46.7% (Taber abrasion test method ASTM D1044).

Example 2 50 parts of the composition (I) obtained in Example 1, xylene and n
67 parts of silica sol (XBA-ST, manufactured by Nissan Chemical Industries, Ltd.) using butyl alcohol as a dispersion medium and 1.5 parts of benzyldimethyl ketal were mixed to obtain an abrasion-resistant ultraviolet-curable coating composition. A hard-coated polycarbonate plate was obtained in the same manner as in Example 1, except that this abrasion-resistant ultraviolet-curable coating composition was used. The adhesion, transparency, and abrasion resistance were evaluated in the same manner as in Example 1.
0/100, cloudiness value: 0.6%, ΔH: 1.0%, and good results were obtained.

Example 3 50 parts of the composition (I) obtained in Example 1, xylene and n
267 parts of silica sol (XBA-ST manufactured by Nissan Chemical Industries, Ltd.) using butyl alcohol as a dispersion medium and 3 parts of benzyldimethyl ketal were mixed to obtain an abrasion-resistant ultraviolet-curable coating composition. A hard-coated polycarbonate plate was obtained in the same manner as in Example 1, except that this abrasion-resistant ultraviolet-curable coating composition was used. When the adhesion, transparency, and abrasion resistance were evaluated in the same manner as in Example 1, the adhesion was 100/1.
00, cloudiness value: 0.6%, ΔH: 0.6%, and good results were obtained.

Example 4 A hard-coated polyethylene terephthalate film was obtained in the same manner as in Example 1 except that a transparent 100 μm thick polyethylene terephthalate film was used instead of the transparent 2 mm thick polycarbonate plate. . The adhesion between the hard coat layer formed on the polyethylene terephthalate film and the polyethylene terephthalate film was evaluated in the same manner as in Example 1.
At 0/100, good adhesion was obtained. When the transparency of the obtained hard-coated polyethylene terephthalate film was evaluated by cloudiness value (%), it was 3.8%.
And the transparency was good. The haze value of the 100 μm-thick polyethylene terephthalate film before the hard coat treatment was 3.7%. Next, when the wear resistance was evaluated, ΔH was 0.6%, and the wear resistance was good. The hard coat treatment was not performed.
ΔH of polyethylene terephthalate having a thickness of 0 μm is 23.
It was one.

Example 5 (Preparation of Component (a)) A mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate containing 67 mol% of dipentaerythritol pentaacrylate (Kayarad DP, manufactured by Nippon Kayaku Co., Ltd.)
HA, a hydroxyl value of 69 mgKOH / g) and tetrahydrophthalic anhydride in 81.3 g and 15.2 g flasks, respectively, so that -COOCO-group / -OH group = 1, and further 30 g of toluene and 0.1 g of hydroquinone monomethyl ether. And reacted at 110 ° C. for 3 hours. The acid value of the reaction was 46 mg KOH / g. Then to this one,
3-glycidoxypropyl trimexisilane 23.6
g, cetyltrimethylammonium bromide 1.2 g
And reacted at 110 ° C. for 12 hours.
mg KOH / g. As a result, a reaction product of a reaction product of dipentaerythritol pentaacrylate and tetrahydrophthalic anhydride with 3-glycidoxypropyltrimethoxysilane (compound B) was prepared in dipentaerythritol hexaacrylate and toluene. . The obtained composition (II) was prepared by adding compound B, dipentaerythritol hexaacrylate, and toluene to 61%, 19%, respectively, based on the total weight of composition (II).
Contains 20%. (Preparation of Wear-Resistant UV-Curable Coating Composition) Composition (I
I) 50 parts, silica sol using xylene and n-butyl alcohol as a dispersion medium (Nissan Chemical Industries: XBA-ST) 13
3 parts and 2 parts of benzyldimethyl ketal,
An abrasion-resistant UV-curable coating composition was obtained. A hard-coated polycarbonate plate was obtained in the same manner as in Example 1, except that this abrasion-resistant ultraviolet-curable coating composition was used.
When the adhesion, transparency and abrasion resistance were evaluated in the same manner as in Example 1, the adhesion was 100/100 and the haze value was 0.6.
%, ΔH: 0.9%, and good results were obtained.

Example 6 (Preparation of component (a)) A mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate containing 67 mol% of dipentaerythritol pentaacrylate (Kayarad DP, manufactured by Nippon Kayaku Co., Ltd.)
HA) and maleic anhydride are converted to a -COOCO- group / -OH
The flasks were placed in 102 g and 9.8 g flasks, respectively, so that the group was 0.8, and 34 g of toluene and 0.11 g of hydroquinone monomethyl ether were further added thereto and reacted at 110 ° C. for 3 hours. The acid value of the reaction was 39 mg KOH / g. Then, 23.6 g of 3-glycidoxypropyltrimethoxysilane and 1.4 g of tetramethylammonium bromide were added thereto, and the mixture was reacted at 110 ° C. for 12 hours. As a result, the acid value became 2 mgKOH / g. As a result, a reaction product (compound C) of a reaction product of dipentaerythritol pentaacrylate and maleic anhydride with 3-glycidoxypropyltrimethoxysilane was converted to dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, and toluene. Prepared in The obtained composition (III) was prepared by adding compound C, dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, and toluene to 51%, 20%, and 9%, respectively, based on the total weight of composition (III). %, 20%
contains. (Preparation of abrasion resistant ultraviolet curable coating composition) Composition (II
I) 50 parts, silica sol using n-butyl alcohol as a dispersion medium (manufactured by Nissan Chemical Industries: NBA-ST, solid content 20%,
200 parts of n-butyl alcohol (80%) and 1 part of benzyldimethyl ketal were mixed to obtain an abrasion-resistant ultraviolet-curable coating composition. A hard-coated polycarbonate plate was obtained in the same manner as in Example 1, except that this abrasion-resistant ultraviolet-curable coating composition was used. When the adhesion, transparency, and abrasion resistance were evaluated in the same manner as in Example 1, the adhesion: 1
00/100, cloudiness: 0.7%, ΔH: 0.7%, showing good results.

Comparative Example 1 50 parts of the composition (I) obtained in Example 1 was stirred and mixed with 133 parts of a silica sol (ST-30, manufactured by Nissan Chemical Industries, 30% solid content) using water as a dispersion medium. However, the solution became cloudy and separated when allowed to stand, and a wear-resistant ultraviolet-curable coating composition that formed a transparent film could not be obtained.

Comparative Example 2 67 mol of dipentaerythritol pentaacrylate
% Of a mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (manufactured by Nippon Kayaku Co., Ltd .: Kayarad DPHA) 35 parts, 3-glycidoxypropyltrimethoxysilane 5 parts, toluene 10 parts, xylene and n-butyl Silica sol using alcohol as a dispersion medium (Nissan Chemical Industries: XBA-ST) 13
3 parts and 2 parts of benzyldimethyl ketal were mixed to obtain an ultraviolet-curable coating composition. A hard-coated polycarbonate plate was obtained in the same manner as in Example 1 except that this ultraviolet-curable coating composition was used. When the adhesion, transparency, and abrasion resistance were evaluated in the same manner as in Example 1, the adhesion was 8:
0/100, cloudiness value: 0.6%, ΔH: 4.2%, and adhesion and abrasion resistance were not sufficient.

Comparative Example 3 2-Vidroxyethyl acrylate and succinic anhydride were
Each of 23.2 g and 10 g was placed in a flask so that -COOCO-group / -OH group = 0.5, and 0.03 g of hydroquinone monomethyl ether was further added thereto, followed by a reaction at 110 ° C for 3 hours. The acid value of the reaction was 170 mg KOH / g. Then, 23.6 g of 3-glycidoxypropyltrimethoxysilane and 0.6 g of tetramethylammonium bromide were added thereto, and the mixture was reacted at 110 ° C. for 6 hours. As a result, the acid value became 2 mgKOH / g. A mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate containing 20 parts of the obtained compound and 67 mol% of dipentaerythritol pentaacrylate (manufactured by Nippon Kayaku Co., Ltd .: Kayarad DPH)
A) 20 parts, 10 parts of toluene, silica sol using xylene and n-butyl alcohol as a dispersion medium (Nissan Chemical: X
BA-ST) 133 parts and benzyl dimethyl ketal 2 parts were mixed to obtain an ultraviolet-curable coating composition. A hard-coated polycarbonate plate was obtained in the same manner as in Example 1 except that this ultraviolet-curable coating composition was used.
Evaluation of adhesion, transparency, and abrasion resistance in the same manner as in Example 1. Adhesion: 100/100, cloudiness: 0.6
%, ΔH: 5.8%, and the wear resistance was not sufficient.

[0019]

According to the present invention, an abrasion-resistant ultraviolet-curable coating composition for forming a coating film having excellent adhesion to a plastic substrate, transparency and abrasion resistance can be obtained.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-11-131013 (JP, A) JP-A-11-123737 (JP, A) JP-A-10-212448 (JP, A) JP-A 8- 27290 (JP, A) JP-A-5-171099 (JP, A) JP-A-5-86205 (JP, A) JP-A-60-217230 (JP, A) JP-A-58-189212 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C09D 4/02 C08J 7/04 CA (STN) CAOLD (STN) REGISTRY (STN) WPIDS (STN)

Claims (2)

(57) [Claims] 1. A compound obtained by reacting an epoxy group-containing silane coupling agent with a reaction product of a hydroxyl group-containing polyfunctional acrylate having a hydroxyl group and three or more acryloyl groups in a molecule and an acid anhydride, (B) a polyfunctional acrylate having three or more acryloyl groups in the molecule, (c)
A wear-resistant ultraviolet-curable coating composition comprising a silica sol containing an organic solvent as a dispersion medium and (d) a photopolymerization initiator. 2. The method according to claim 1, wherein (b) the polyfunctional acrylate having three or more acryloyl groups in the molecule is selected from the group consisting of dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate and a mixture thereof. A composition as described.