JPH0723431B2 - Coating composition and synthetic resin molded article using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a coating composition for surface curing of synthetic resin molded articles, sheets and films, and weathering of the composition by UV irradiation, especially prevention of coloration over time. The present invention relates to a synthetic resin molded product on which a coating film having excellent wear resistance, hardness, adhesion and flexibility is formed.

<Prior art> Compared with glass products, synthetic resin molded products are not only superior in characteristics such as lightness and toughness, but also have advantages such as low cost and easy molding, and are used in a wide range of fields. There is. However, since these synthetic resin molded products lack surface hardness and wear resistance, the surfaces are easily damaged by the effects of contact, impact, scratching, etc. Various methods for forming a cross-linked cured coating have been conventionally studied. For example, a method has been proposed in which a polymerizable monomer is applied to the surface of a synthetic resin molded article, and then ultraviolet rays are irradiated to form a crosslinked cured coating on the surface to obtain a coating having excellent abrasion resistance. (Japanese Patent Publication 48-
No. 42211, Japanese Patent Publication No. 49-22951, and Japanese Patent Laid-Open No. 53-1029.
36, JP-A-53-104638, JP-A-58-101121
However, although abrasion resistance, which is a drawback of synthetic resin molded products, is improved by these methods, photodegradation due to sunlight, artificial rays, etc. remains a practical problem, Improvement of weather resistance is often required. As a method for improving such defects, a method for applying a coating composition containing various light stabilizers, irradiating ultraviolet rays or the like to form a crosslinked cured coating on the surface, and obtaining a coating excellent in weather resistance, etc. Is proposed. (JP-A-56-141309) Also, as a conventionally known technique, a light stabilizer and an antioxidant are combined for improving weather resistance, or two kinds of light stabilizers such as an ultraviolet absorber and a hindered amine are used. It is known that a great effect can be seen by combining with a light stabilizer. (Chemical industry 5,72 (1985)) <Problems to be solved by the invention> However, a synthetic resin molded article is produced by using a coating composition containing such an additive as a light stabilizer and an antioxidant. Even if a film is applied, sufficient weather resistance is not always obtained, and if hardness and wear resistance are to be improved, problems such as poor flexibility and generation of cracks in the heat cycle test are likely to occur. There is. Particularly in the case of weather resistance, in the case of synthetic resin moldings such as vinyl chloride resin, coloring with time is remarkable, and strong improvement has been desired. Further, from the viewpoint of the manufacturing process, when it is irradiated with ultraviolet rays in the air, it is necessary that the curability is excellent, and it is necessary to satisfy the above-mentioned quality problems. The present inventors have arrived at the present invention as a result of extensive studies to improve these points. That is, when the surface-curing composition of the present invention is applied to a synthetic resin molded article and irradiated with ultraviolet rays in the air, the curability is very good, and hardness, abrasion resistance, flexibility, and prevention of crack formation in a heat cycle test. It has been found that a coating film having excellent balance properties and having excellent weather resistance (no change in coloring and abrasion resistance with time) and excellent adhesion is formed.

<Means for Solving the Problems> The present invention relates to a. A. A polyhydric alcohol having 4 or more hydroxyl groups in one molecule, and a polyfunctional monomer 20 to which the hydroxyl groups are substituted with 3 or more acryloyloxy groups. 75 parts by weight of b. Dipentaerythritol, tripentaerythritol, itrimethylolpropane or ditrimethylolethane, a polyfunctional polyester acrylate or polyisocyanate compound obtained by co-esterification with dicarboxylic acid and acrylic acid, and a hydroxyl group-containing polymerizable acrylic resin. 10-60 parts by weight of one or both of the polyfunctional urethane acrylates obtained by the reaction with the monomer, and c. Monomer having a boiling point of 150 ° C or higher (normal pressure) and a viscosity of 10 centipoise or lower (25 ° C). 100 parts by weight of acrylate mixture consisting of 0 to 40 parts by weight of diacrylate On the other hand, 0.01 to 5 parts by weight of a light stabilizer having at least one or more cyclic hindered amine structure, 0.01 to 5 parts by weight of at least one antioxidant, and 0.01 to 5 parts by weight of at least one ultraviolet absorber. A coating composition consisting of an additive and a photosensitizer added to the coating composition and applied to a synthetic resin molded article, sheet or film, and then irradiated with ultraviolet rays to form a cured film on the surface. It is a synthetic resin molded product characterized by the above.

Examples of the polyhydric alcohol in the above a) include pentaerythritol, diglycerin, ditrimethylolethane, ditrimethylolpropane, dipentaerythritol, and tripentaerythritol.

Therefore, the polyfunctional monomer having three or more acryloyloxy groups in one molecule is a polyacrylate of a triacrylate or higher of those polyhydric alcohols.

These may be used alone or in combination of two or more within the composition range thereof.

Specific examples of the dicarboxylic acid in the above b) include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid, alicyclic dicarboxylic acids such as hexahydrophthalic acid and methylhexahydrophthalic acid, succinic acid and malon. And saturated and unsaturated aliphatic dicarboxylic acids such as acids, adipic acid, sebacic acid, maleic acid.

Further, anhydrides of the above carboxylic acids can be used as well. Among these dicarboxylic acids, hexahydrophthalic acid, tetrahydrophthalic acid, malonic acid, succinic acid, glutaric acid, adipic acid and sebacic acid can be preferably used. Acrylic acid as well as these dicarboxylic acids, ditrimethylolethane, ditrimethylolpropane, dipentaerythritol or tripentaerythritol using a polyester acrylate by a co-esterification reaction, the curability by ultraviolet irradiation in the air is very good, It is possible to impart flexibility to the cross-linked cured coating without lowering the wear resistance of the cross-linked cured coating and enhance the adhesion to the substrate. Further, it is possible to suppress the generation of cracks in the weather resistance test and increase the crosslink density, and as a result, it is possible to improve hardness and wear resistance.

The molar ratio of dicarboxylic acid, acrylic acid and ditrimethylolethane or ditrimethylolpropane used when synthesizing polyester acrylate is 0.4 to 0.8: 3.3 to 2.0:
1 is preferred. Further, in the case of dipentaerythritol, 0.4 to 0.8: 5.5 to 3: 1 is preferable, and in the case of tripentaerythritol, 0.4 to 0.8: 8 to 4: 1 is preferable. The ester reactability at this time is not particularly limited and can be carried out by a conventional method. Further, one kind of polyester acrylate can be used, and two or more kinds thereof may be mixed in the composition range. Aliphatic dicarboxylic acids, such as polyester acrylates derived from hexahydrophthalic anhydride, tetrahydrophthalic anhydride, etc., are compared to aliphatic dicarboxylic acids such as succinic acid, malonic acid, adipic acid, sebacic acid, etc. It is particularly preferable because it has excellent crack resistance after the weather resistance test.

Further, as the polyisocyanate compound in the above-mentioned component b), tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isophoon diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, or aromatic isocyanates among these diisocyanate compounds is used. Diisocyanate compound obtained by hydrogenation (for example, diisocyanate compound such as hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate) triphenylethane triisocyanate, dimethylene triphenyl triisocyanate,
A divalent or trivalent polyisocyanate compound such as the above, or a polyisocyanate compound obtained by polymerizing a diisocyanate compound is used.

Further, the hydroxyl group-containing polymerizable acrylic monomer includes 1,6-hexanediol diacrylate and glycerin diacrylate obtained by partial esterification reaction of polyhydric alcohols such as β-hydroxyethyl acrylate and β-hydroxypropyl acrylate with acrylic acid. Examples thereof include acrylate, trimethylolpropane diacrylate, ditrimethylolpropane triacrylate, and dipentaerythritol tetraacrylate.

Specific examples of the mono- and diacrylates having a boiling point of 150 ° C. or higher (normal pressure) and a viscosity of 10 centipoise or lower (25 ° C.) in the component c) include tetrahydrofurfuryl acrylate, 2-hydroxyethyl acrylate,
2-Hydroxypropyl acrylate, 1,6-hexanediol diacrylate, 1,3-butanediol diacrylate, neopentyl glycol diacrylate and the like are preferable. These may be used alone or in a mixture of two or more within the composition range.

Mono- and diacrylates give a smooth surface to the crosslinkable cured coating formed on the synthetic resin molded product,
Necessary to provide flexibility as well as adhesion. The monoacrylic acid ester is not particularly limited as long as it has the above-mentioned physical properties, but one having a hydroxyl group, a cyclic ether bond or an ester bond is particularly preferable because it has excellent polymerizability in air. Further, as the light stabilizer added to the acrylate mixture, 4-benzoyloxy-
2,2,6,6-Tetramethylpiperidine, sebacic acid-bis (2,2,6,6-tetramethyl-4-piperidyl), sebacic acid-bis (N-methyl-2,2,6,6- Tetramethyl-4
-Piperidyl), and other oligomer type and polymer type light stabilizers having a cyclic hindered amine structure are used.

Antioxidants include 2,6-di-t-butyl-4-methylphenol, tetrakis- [methylene-3- (3 ', 5'
-Di-t-butyl-4'-hydroxyphenyl) propionate] methane and other hindered phenol derivatives,
Phosphite derivatives such as trinonylphenyl phosphite and triphenyl phosphite are used.

Examples of the ultraviolet absorber include hydroxybenzoate derivatives such as 2,4-di-t-butylphenyl-3 ', 5'-di-t-butyl-4'-hydroxybenzoate, phenyl salicylate and 4-t-butylphenyl. Salicylate derivatives such as salicylate, benzophenone derivatives such as 2,4-dihydroxybenzophenone and 2-hydroxy-4-methoxybenzophenone, cyanoacrylate derivatives such as ethyl-2-cyano-3,3-diphenylacrylate, 2- ( 2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl)-
Benzotriazole derivatives such as 5-chlorobenzotriazole are used. The above-mentioned components a), b),
The composition of the coating composition of the present invention comprising c), a light stabilizer, an antioxidant and an ultraviolet absorber will be described in detail. The content of the polyfunctional monomer of component a) is 20 to 75 parts by weight, preferably 30 to 65 parts by weight. If the proportion of the polyfunctional monomer is less than 20 parts by weight, a cured coating with sufficient abrasion resistance cannot be obtained, and if it exceeds 75 parts by weight, the abrasion resistance is good, but the flexibility and synthetic resin molding The film has poor adhesion, and the heat cycle resistance and weather resistance are also reduced.

The component b) polyester acrylate may be one or two.
One or more dicarboxylic acids or dipentaerythritol,
Tripentaerythritol, ditrimethylolpropane, and ditrimethylolethane can be used in combination, and the content of polyester acrylate is 10 to 60 parts by weight, preferably 15 to 50 parts by weight. If the amount of polyester acrylate exceeds 60 parts by weight, the wear resistance of the cured coating decreases, and if it is less than 10 parts by weight, the cured coating has flexibility and adhesion to synthetic resin molded products, heat cycle resistance and weather resistance. Is reduced, which is not preferable. The same can be said for the case of polyfunctional urethane acrylate as for the case of polyester acrylate. The same can be said when a polyester acrylate and a polyfunctional urethane acrylate are used in combination.

The content of mono- and diacrylates of component c) is 0
To 40 parts by weight, preferably 0 to 30 parts by weight. If the content of the mono- and di-acrylic acid ester exceeds 40 parts by weight, a sufficient cured film cannot be obtained. The boiling point (normal pressure) of the mono- and di-acrylic acid esters is 150 ° C.
When it is lower than the above range, the coating composition of the present invention tends to volatilize when applied to the surface of a synthetic resin molded article and cured, which is not preferable. The viscosity is 10 centipoise (25
If it exceeds (° C.), the viscosity of the coating composition becomes high, which is not preferable. By using a light stabilizer, an antioxidant, and an ultraviolet absorber, improvement of weather resistance,
In particular, it is possible to improve the effect of preventing coloration over time and improve wear resistance. The amount of light stabilizer used is 10% by weight of the acrylate mixture of the present invention.
0.01 to 5 parts by weight, preferably 0.1 to 2 parts by weight, or the amount of the antioxidant used is 0.01 to 5 parts by weight, preferably 0.05 to 100 parts by weight of the acrylate mixture of the present invention.
The amount of the ultraviolet absorber used is 0.01 to 5 parts by weight, preferably 0.05 to 1 part by weight, based on 100 parts by weight of the acrylate mixture of the present invention. However, if the amount of the light stabilizer used is too small, the abrasion resistance is lowered. If the amount is too large, the anti-coloring effect is weakened and the adhesion is deteriorated, which is not preferable. If the amount of the antioxidant and the amount of the ultraviolet absorber used are too small, the anti-coloring effect will be weakened, and if the amount is too large, the adhesiveness will be deteriorated. Further, the light stabilizer, antioxidant and ultraviolet absorber may be used alone or in combination of two or more.

Compared to the case of using the above three types, no anti-coloring effect was observed in the case where only the light stabilizer was added, and the abrasion resistance was improved in the case where only the antioxidant or the ultraviolet absorber was added. Is not recognized at all. Further, the system using two light stabilizers and antioxidants together and the system using two light stabilizers and ultraviolet absorbers together do not have sufficient coloring preventing effect. No improvement in wear resistance is observed in the system in which the two are used together.

Next, the method of using the coating composition of the present invention will be described in detail. The coating composition of the present invention is mixed with a suitable solvent and a photosensitizer, applied to a synthetic resin molded article, and then irradiated with ultraviolet rays to be cured. In addition, α rays, β rays, γ
It can also be cured by irradiation with active energy rays such as rays and electron rays. As a photosensitizer, benzoin, benzoin ethyl ether, 2-hydroxy-2-methyl-1
-Phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, azobisisobutyronitrile, benzoyl peroxide and other generally known photosensitizers are used. The amount of these photosensitizers used is 1 to 10 parts by weight, preferably 2 to 5 parts by weight, based on 100 parts by weight of the coating composition of the present invention. If the amount of the photosensitizer used is too large, the cured film will be colored, and if it is too small, insufficient curing will occur.

Examples of the solvent include alcohols such as ethanol, propanol, isopropanol and butanol, aromatic hydrocarbons such as benzene and toluene, acetic acid esters such as ethyl acetate and butyl acetate, ketones such as acetone and methyl ethyl ketone, and 2- (2 Ethers such as -ethoxyethoxy) ethanol, glycol monomethyl ether, glycol monoethyl ether and dioxane are used.

The solvent may be used in an amount of 0 to 250 parts by weight per 100 parts by weight of the coating composition of the present invention.

As the synthetic resin molded article for surface-coating the coating composition of the present invention, a thermoplastic resin molded article, a thermosetting resin molded article is used without distinction, for example, polymethyl methacrylate, polycarbonate, polyallyl diglycol carbonate resin, ABS. Molded products such as resin, polystyrene, PVC, polyester resin, and acetate resin are used. Especially in the case of PVC, it can be seen that by using the coating composition of the present invention, the weather resistance, in particular, the effect of preventing coloration over time is significantly exhibited as compared with the prior art. As a coating method, a known method such as brush coating, spray coating, roll coating, and dipping method may be appropriately used. The point is that any method can be used as long as a desired uniform thickness and a smooth surface can be obtained, and it is preferable to appropriately select it according to the shape of the object to be coated.

The thickness of the coating is in the range of 1 to 30μ, preferably 2.5 to 20μ, and if it is 1μ or less, sufficient hardness cannot be obtained.
If it exceeds 30 μ, cracks are likely to occur.

<Effects of the Invention> A coating composition composed of a polyester acrylate synthesized using dipentaerythritol, tripentaerythritol, ditrimethylolpropane or ditrimethylolethane, or a polyfunctional urethane acrylate of the present invention contains another polyhydric alcohol. It can be seen that the coating composition is superior in hardness and weather resistance as compared with the coating composition composed of the acrylate synthesized. Further, the coating composition of the present invention is a light stabilizer,
It can be seen that it is superior in weather resistance, especially in prevention of coloration over time and abrasion resistance, as compared with a system in which additives such as an antioxidant and an ultraviolet absorber are removed. Furthermore, the coating composition of the present invention is excellent in heat cycle resistance test and flexibility.

<Examples> Examples will be specifically described below, but the present invention is not limited to these examples.

Production Example of Coating Composition Components a. Polyfunctional Monomer Synthesis Example 1 Synthesis of Dipentaerythritol Hexaacrylate In a glass reactor equipped with a stirrer, thermometer, and water separator, 127 g of dipentaerythritol and 259 acrylic acid.
g, 127 g of mixed solvent (benzene: cyclohexane = 2: 1)
Sulfuric acid 6.35 g, copper sulfate 0.51 g, and hydroquinone monomethyl ether 0.03 g were charged.

The reaction is carried out under reflux while stirring and blowing air, the distilling organic solvent-water azeotrope is separated from water after cooling, the organic solvent is reacted by returning to the reaction system, water 52C.C. Distilled. Then, the reaction solution was cooled, 254 g of a mixed solvent (benzene: cyclohexane = 2: 1) was added, the solution was neutralized with an aqueous solution of caustic soda having a concentration of 10%, and then separated, and the oil layer was washed with a 10% saline solution.

The oil was dried over anhydrous magnesium sulfate, and the mixed solvent (benzene: cyclohexane = 2: 1) was removed under reduced pressure at 50 to 60 ° C. to obtain 271 g of dipentahexaacrylate as a residue of the kettle. This product has a viscosity of 9410 cps / 25 ° C and an ester value of 552.
(Theoretical value 582.5).

Synthesis Example 2 Synthesis of ditrimethylolpropane propane tetraacrylate Substituting 127 g of dipentaerythritol of Synthesis Example 1 with 125 g of ditrimethylolpropane and 259 g of acrylic acid with 173 g, the same reaction as in Synthesis Example 1 was carried out. 223 g of tetraacrylate was obtained.

This product had a viscosity of 568 cps / 25 ° C and an ester value of 470 (theoretical value: 482).

b. Polyester acrylate Synthesis Example 1 127 g (0.5 mol) of dipentaerythritol, 38 g (0.26 mol) of adipic acid, 187 g (2.6 mol) of acrylic acid were added to 1 glass reactor equipped with a stirrer, thermometer, and water separator. , Benzene 127 g, sulfuric acid 6.3 g, copper sulfate 0.5 g, and hydroquinone monomethyl ether 0.03 g were charged.

While stirring and blowing air, the reaction is carried out under reflux, and the benzene and water azeotrope that distills out is separated from water after cooling, and benzene reacts by returning to the reaction system, distilling water 52C.C. did. Then, the reaction solution was cooled, a mixed solvent of benzene: cyclohexane (5: 1) was added, and the mixture was neutralized with an aqueous solution of caustic soda having a concentration of 10%, then separated, and the oil layer was washed with a 10% saline solution. Oil is dried over anhydrous magnesium sulfate 50-60
The benzene-cyclohexane mixed solvent was removed under reduced pressure at ℃, and 30 g of pale yellow polyester acrylate was obtained as a residue in the kettle. This product has a viscosity of 3020 cps at 50 ° C and an ester value of 519.
Met.

Synthesis Examples 2 to 16 Polyester acrylates were synthesized by carrying out the esterification reaction in the same manner as in Synthesis Example 1 except that the amounts of polyhydric alcohol, dicarboxylic acid and acrylic acid were changed. The results are shown in Table-1.

b. Polyfunctional Urethane Acrylate Synthesis Example 17 242 g of trimethylolpropane diacrylate and 0.25 g of hydroquinone monomethyl ether were placed in a glass reactor 1 equipped with a stirrer, a thermometer and a dropping funnel, and the temperature was adjusted to 6
2,4-Tolylene diisocyanate 85
g was added dropwise over 1 hour. Stir at the same temperature for 1 hour,
Add 0.05 g of dibutyltin diacetate and add 2 more
After continuing the reaction for a time to complete the reaction, 325 g of a polyfunctional urethane acrylate was obtained. The isocyanate content of this product was 0.03%.

Synthetic Examples 18 to 31 A polyfunctional urethane acrylate was synthesized by performing the reaction in the same manner as in Synthetic Example 17 except that the types and amounts of the hydroxyl group-containing polymerizable monomer and the polyisocyanate were changed. The results are shown in Table-2.

Comparative Synthesis Example 1 (Synthesis 1 of Comparative Polyester Acrylate) (When Polyhydric Alcohol Other Than the Present Invention is Used) Trimethylolethane 120.2 g (in a glass flask 2 equipped with a stirrer, a thermometer, and a water separator) ( 1 mole), 65.0 g of succinic acid (0.55 mol), 158.6G acrylic acid (2.20 mol), was charged toluene 1000 g, Cu Cl ₂ 3 g, the p- toluenesulfonic acid 13.5 g.

While stirring and blowing air, the reaction is carried out under reflux, the toluene-water azeotrope to be distilled out is separated from water after cooling, and the toluene is reacted by returning it to the reaction system, and water 52C.C. is distilled. I put it out. After cooling the reaction solution, the oil layer was separated and the oil layer was adjusted to 0.
It was washed twice with a 5% sulfuric acid aqueous solution and further washed three times with pure water. After washing, the oil is dried over anhydrous magnesium sulfate and then 50-
Toluene was removed under reduced pressure at 60 ° C. to obtain a pale yellow polyester acrylate as a residue in the kettle. The viscosity of this compound is 20
It was 8300 cps at ℃.

Comparative Synthesis Example 2 (Synthesis 2 of Comparative Polyester Acrylate) (When Polyhydric Alcohol Other than the Present Invention is Used) 120.2 g (1 mol) of trimethylolethane of Comparative Synthesis Example 1
Was changed to 136 g (1 mol) of pentaerythritol, and the reaction was performed in the same manner as in Comparative Synthesis Example 1 except that 158.6 g (2.2 mol) of acrylic acid was changed to 237.9 g (3.3 mol). Got The viscosity of this compound was 1550 cps at 50 ° C.

Examples 1 to 10 and Comparative Examples 1 to 20 As shown in Table 3 and Table 4, the coating composition of the present invention was blended with a solvent and a photosensitizer and the thickness was
A 2 mm hard vinyl chloride resin plate (made by Taiki Equipment Co., Ltd.) is dipped to form a coating film, left for 20 minutes, and then the resin plate is placed in the air for a metal halide lamp (UE Graphics UE
0151-302C, M015-L31) from a distance of 100 mm to 120
W, UV irradiation for 5 seconds. The weather resistance, hardness, appearance, and adhesion of the vinyl chloride resin plate formed of the cured coating film thus obtained were investigated and are shown in Tables 3 and 4, 5. The composition in the table and the description of the evaluation method are as follows.

Note 1) Monoacrylic ester: Tetrahydrofurfuryl acrylate 2) Solvent: Toluene: Isopropanol = 1: 1 3) Photosensitizer: 1-Hydroxycyclohexyl phenyl ketone 4) Abrasion resistance: Abrasion test with # 0000 steel A : No scratches even with strong rubbing B: Slight scratches with strong rubbing C: Slight scratches with light rubbing D: Significant scratches with light rubbing 5) Hardness: Pencil hardness according to JIS K5651-1966 6) Adhesion Cross-cut cellophane tape peeling test ... 1mm for coating
Insert 11 film cutting lines in each of the vertical and horizontal directions to reach the base material, make 100 1mm ² grids, and attach cellophane tape on them to rapidly peel off. This cellophane tape operation was repeated 3 times at the same location, and the number of unpeeled cells is shown.

7) Weather resistance Atlas Yubucon (Toyo Seiki Seisakusho) was used as an accelerated exposure acceleration test device. The conditions are repeated UV exposure at 60 ° C. for 4 hours and then wet exposure at 40 ° C. for 4 hours.
Under these cycle conditions, appearance steel wool test and adhesion after 300 hours and 500 hours were performed.

8) Heat cycle test A molded article with a cured coating formed on the surface is immersed in warm water at 65 ° C for 1 hour, then immediately immersed in ice water for 10 minutes, and then at 80 ° C.
The operation of drying for 1 hour is repeated 5 times. After the heat cycle test, the appearance, abrasion resistance and adhesion are tested.

9) Light stabilizer sebacic acid-bis (2,2,6,6-tetramethyl-4-piperidine) 10) Light stabilizer sebacic acid-bis (N-methyl-2,2,6,6-tetramethyl- 4-piperidine) 11) Light stabilizer 4-benzoyloxy-2,2,6,6-tetramethylpiperidine 12) Light stabilizer 4-octanoyl-2,2,6,6-tetramethylpiperidine 13) Antioxidant Tetrakis- [methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] 14) Antioxidant n-octadecyl-3- (3', 5'-di-t- Butyl-
4'-Hydroxyphenyl) propionate] 15) Antioxidant Trinonylphenyl phosphite 16) Antioxidant triphenyl phosphite 17) UV absorber 2-hydroxy-4-methoxybenzophenone 18) UV absorber 2- (2 '-Hydroxy-5'-methylphenyl) benzotriazole 19) UV absorber 2- (2'-hydroxy-3 ', 5'-di-t-butylphenyl) benzotriazole 20) UV absorber ethyl-2-cyano- 3,3-diphenyl acrylate

Claims (4)

[Claims] 1. A). A polyhydric alcohol having 4 or more hydroxyl groups in one molecule, and 20 to 75 parts by weight of a polyfunctional monomer in which 3 or more acryloyloxy groups are substituted for the hydroxyl groups, and b). Obtained by reacting dipentaerythritol, tripentaerythritol, ditrimethylolpropane or ditrimethylolethane with a dicarboxylic acid and acrylic acid to obtain a polyfunctional polyester acrylate or polyisocyanate compound and a hydroxyl group-containing polymerizable acrylic monomer. 10 to 60 parts by weight of one or both of the polyfunctional urethane acrylates and c). 0 to 40 mono- and diacrylates with a boiling point of 150 ° C or higher (normal pressure) and a viscosity of 10 centipoise or lower (25 ° C)
0.01 to 5 parts by weight of at least one or more light stabilizer having a cyclic hindered amine structure, at least one or more kinds of antioxidants to 0.01 to 5 parts by weight, and further at least one kind to 100 parts by weight of an acrylate mixture consisting of A coating composition comprising 0.01 to 5 parts by weight of the above ultraviolet absorber. 2. The coating composition according to claim 1, wherein the polyhydric alcohol is dipentaerythritol, tripentaerythritol, ditrimethylolpropane or ditrimethylolethane. 3. A). In a polyhydric alcohol having 4 or more hydroxyl groups in one molecule, 20 to 75 parts by weight of a polyfunctional monomer in which the hydroxyl groups are substituted with 3 or more acryloyloxy groups, and b). A polyfunctional polyester acrylate obtained by co-esterifying dipentaerythritol, tripentaerythritol, ditrimethylolpropane or ditrimethylolethane with dicarboxylic acid and acrylic acid, or by reacting a polyisocyanate compound with a hydroxyl group-containing polymerizable acrylic monomer. Either one or both of the polyfunctional urethane acrylates are
Parts by weight and c). 0 to 40 mono- and diacrylates with a boiling point of 150 ° C or higher (normal pressure) and a viscosity of 10 centipoise or lower (25 ° C)
0.01 to 5 parts by weight of at least one or more light stabilizer having a cyclic hindered amine structure, at least one or more kinds of antioxidants to 0.01 to 5 parts by weight, and further at least one kind to 100 parts by weight of an acrylate mixture consisting of A surface-hardening coating is prepared by adding a photosensitizer to a coating composition consisting of the addition of 0.01 to 5 parts by weight of the above-mentioned ultraviolet absorber, coating the composition on a synthetic resin molded article, sheet or film, and then irradiating it with ultraviolet rays. A synthetic resin composition characterized by being formed. 4. The synthetic resin molded article according to claim 3, wherein the polyhydric alcohol is dipentaerythritol, tripentaerythritol, ditrimethylolpropane or ditrimethylolethane.