JP6794681B2 - Metal surface topcoat composition and resin molded product - Google Patents

Description

The present invention relates to a metal surface topcoat composition, for example, a metal surface topcoat used for coating the surface of a resin molded product on a metallized surface by vacuum deposition or sputtering, and forming a topcoat by irradiation with active energy rays. Regarding the composition.

Ultraviolet curable resins are widely used because they are excellent in productivity and energy saving when forming a coating film. For example, Patent Document 1 describes that an ultraviolet curable resin can be used as a topcoat material for a metal surface obtained by metallizing the surface of a resin molded product by vacuum deposition or sputtering. Examples of such resin molded products to be metallized include lighting, reflectors such as lights, reflector parts, home appliances such as mobile phones, and cosmetic containers.

JP-A-2010-031152

However, the top coat formed by using the ultraviolet curable resin described in Patent Document 1 has good scratch resistance and adhesion, but has a problem that interference fringes are generated and a good appearance cannot be obtained. Therefore, an object of the present invention is to provide a metal surface topcoat composition capable of suppressing the occurrence of interference fringes on a metal surface and forming a topcoat layer having an excellent balance between scratch resistance and adhesion.

As a result of diligent studies to solve the above problems, the present inventors have combined a specific compound into the composition to suppress the occurrence of interference fringes without deteriorating the scratch resistance and to have excellent adhesion. We have found that a coating film having the above can be obtained, and have reached the present invention.
In the present invention, a copolymer (A) containing 15 to 60% by mass of a structural unit derived from a vinyl-based monomer having a ring structure in which the glass transition temperature of a homopolymer is 100 ° C. or higher, and a urethane di having a bisphenol skeleton ( A metal surface topcoat composition containing each component of a compound (C) having a (meth) acryloyl group other than the meta) acrylate (B) and the urethane (meth) acrylate (B), wherein the component (A), ( The component (A) is 16 to 35% by mass, the component (B) is 15 to 40% by mass, and the component (C) is 25 to 69, based on a total of 100% by mass of the component B) and the component (C). The composition is in mass%.

The metal surface topcoat composition of the present invention is applied to a metal surface and irradiated with active energy rays to suppress the occurrence of interference fringes and form a topcoat layer having an excellent balance between scratch resistance and adhesion. be able to. When this composition is used as a top coat material for a metallized resin molded product, it is possible to obtain a metallized resin molded product having excellent appearance and durability, particularly a metallized resin molded product used for mobile phones and cosmetic containers. it can.

Hereinafter, the present invention will first describe the components of the metal surface topcoat composition (hereinafter, also referred to as “the present composition”).

The component (A) used in the present invention has a copolymer weight containing a structural unit derived from a vinyl-based monomer (a-1) having a ring structure in which the glass transition temperature (Tg) of the homopolymer is 100 ° C. or higher. It is a coalescence. The component (A) is obtained by, for example, polymerizing a mixture of monomers containing a vinyl-based monomer (a-1) in the presence of a radical polymerization initiator by a solution polymerization method, a massive polymerization method, an emulsion polymerization method, or the like. Can be manufactured. The component (A) is a component that alleviates the polymerization shrinkage that occurs when the coating film of the present composition is irradiated with active energy rays and is cured, and improves the adhesion to the metal surface. Further, since the component (A) has a ring structure, it is a component that improves the refractive index of the cured film of the present composition, and by improving the refractive index of the cured film, the occurrence of interference fringes can be suppressed. The Tg of the homopolymer can be obtained by using the value described in the Polymer Handbook "PolymerHandBook, J. Brandrup, Interscience, 1998". If not stated, it can be calculated using a measured value of a differential scanning calorimeter or the like.

Specific examples of the vinyl-based monomer (a-1) include dicyclopentanyl methacrylate (175 ° C.), dicyclopentanyl acrylate (120 ° C.), dicyclopentenyl methacrylate (120 ° C.), and isobornyl methacrylate (20 ° C.). 150 ° C.), acryloylmorpholine (147 ° C.), adamantyl methacrylate (141 ° C.), adamantyl acrylate (153 ° C. ) (temperature in parentheses is Tg). Among these, dicyclopentanyl methacrylate and isobornyl methacrylate are preferable because the homopolymer has a high Tg, a high refractive index, and is easily available. In addition, "(meth) acrylic" is a general term for "acrylic" and "methacryl", and other "(meta) acrylic ..." is also a group derived from "acrylic" and "methacryl". It is a generic term.

These vinyl-based monomers (a-1) may be used alone or in combination of two or more.
The proportion of the structural unit derived from the vinyl-based monomer (a-1) contained in the component (A) is 15 to 60% by mass, preferably 30 to 50% by mass. The higher the ratio, the higher the refractive index of the cured film, and the smaller the ratio, the higher the adhesion of the cured film.
The component (A) contains a structural unit derived from a vinyl-based monomer (a-2) other than the vinyl-based monomer (a-1). The vinyl-based monomer (a-2) is not particularly limited, and a vinyl-based monomer copolymerizable with the vinyl-based monomer (a-1) can be used. Specific examples of the vinyl-based monomer (a-2) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, and the like. Isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, methoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-Hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, styrene, α-methylstyrene, pt-butylstyrene, vinyltoluene, N, N-dimethyl ( Examples thereof include meta) acrylamide, N, N-diethyl (meth) acrylamide, (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid and the like. The vinyl-based monomer (a-2) may be used alone or in combination of two or more.

The blending amount of the component (A) in the present composition is 16 to 35% by mass with respect to the total 100% by mass of the components (A) to (C). The larger the amount of the component (A), the higher the refractive index of the cured film, so that interference fringes are suppressed, and the smaller the amount, the higher the scratch resistance of the cured film tends to be. From the viewpoint of the balance between the suppression of interference fringes and the scratch resistance, the amount of the component (A) is preferably 20 to 30% by mass.

The component (B) is a urethane di (meth) acrylate having a bisphenol skeleton. The component (B) can be produced, for example, by reacting a diol (b-1) having a bisphenol skeleton, a diisocyanate (b-2) and a hydroxyalkyl (meth) acrylate (b-3).

Specific examples of the diol (b-1) include an ethylene oxide adduct of bisphenol A (additional number n = 1 to 15), a propylene oxide adduct (additional number n = 1 to 15), and a caprolactone adduct (additional number n = 1 to 15). Addition mole number n = 1 to 10) Further, ethylene oxide adduct of bisphenol S (addition mole number n = 1 to 10), propylene oxide adduct (addition mole number n = 1 to 10), and the like can be mentioned. .. As a raw material for the component (B), these diols can be used alone or in combination of two or more. Among these, the bisphenol A ethylene oxide adduct is preferable, and the bisphenol A ethylene oxide 1 mol adduct and the bisphenol A ethylene oxide 2 mol adduct are more preferable because they are easily available industrially.

Specific examples of the diisocyanate (b-2) include tolylene diisocyanis, xylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexamethylene diisocyanate, methylcyclohexane diisocyanate, norbornene diisocyanate, tolylene diisocyanate, and hydrogenated xylene diisocyanate. Examples thereof include isocyanate, naphthalene diisocyanate, tetramethylxylene diisocyanate, diisocyanate dimerate, and trimethylhexamethylene diisocyanate. As the raw material of the component (B), these diisocyanates can be used alone or in combination of two or more. Among these, isophorone diisocyanate is preferable in that the viscosity of the obtained component (B) is lowered and the workability at the time of coating of the present composition is improved.

Specific examples of the hydroxyalkyl (meth) acrylate (b-3) component include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl. Hydroxyl group-containing (meth) acrylates such as (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and pentaerythritol tri (meth) acrylate; represented by caprolactone-modified products and alkylene oxide-modified products of hydroxyl group-containing (meth) acrylates. Examples thereof include hydroxyl group-containing (meth) acrylate-modified products; addition reactants of monoepoxy compounds such as butyl glycidyl ether, 2-ethylhexyl glycidyl ether, and glycidyl (meth) acrylate with (meth) acrylic acid. As a raw material for the component (B), these hydroxyalkyl (meth) acrylates can be used alone or in combination of two or more. Among these, 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) are obtained in that the viscosity of the obtained component (B) is lowered and the workability when coating the composition is improved. ) Acrylate, 4-hydroxybutyl (meth) acrylate is preferable.

The addition reaction for producing the component (B) from the components diol (b-1), diisocyanate (b-2) and hydroxyalkyl (meth) acrylate (b-3) can be carried out according to various conventionally known methods. For example, diisocyanate (b-2) is added dropwise over 2 to 6 hours to a mixture of a diol (b-1) heated to 30 to 90 ° C. and a catalyst such as dibutyltin dilaurate, and further added to 1 to 3 hours. A method of synthesizing the component (B) can be mentioned by reacting, then dropping hydroxyalkyl (meth) acrylate (b-3) over 1 to 3 hours, and further reacting for 1 to 3 hours.

The blending amount of the component (B) in the present composition is 15 to 40% by mass with respect to the total 100% by mass of the components (A) to (C). The larger the amount of the component (B), the higher the refractive index of the cured film, so that interference fringes are suppressed, and the smaller the amount, the higher the scratch resistance of the cured film tends to be. From the viewpoint of suppressing interference fringes, the amount of the component (B) is preferably 30 to 40% by mass.

The component (C) is a compound having a (meth) acryloyl group other than the component (B). Specific examples of the component (C) include hexafunctional (meth) acrylic acid esters such as dipentaerythritol hexa (meth) acrylate and caprolactone-modified dipentaerythritol hexa (meth) acrylate;
Five-functional (meth) acrylic acid esters such as dipentaerythritol hydroxypenta (meth) acrylate and caprolactone-modified dipentaerythritol hydroxypenta (meth) acrylate;

Tetrafunctional (meth) acrylic acid esters such as ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, and pentaerythritol ethoxy-modified tetra (meth) acrylate;
Trimethylolpropane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ethoxylated pentaerythritol tri (meth) acrylate, tris (2-hydroxyethyl) isocyanurate Polyfunctional trifunctional (meth) acrylic acid ester such as tri (meth) acrylate;

Ethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, methyl Pentandiol di (meth) acrylate, neopentyl glycol di (meth) acrylate of hydroxypivalate, tetraethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tricyclodecanedimethanol di (meth) acrylate, bis (2-Acryloyloxyethyl) -2-hydroxyethyl isocyanurate, cyclohexanedimethanol di (meth) acrylate, polyethoxylated bisphenol A di (meth) acrylate, hydrogenated bisphenol A di (meth) acrylate, polyethoxylated Hydrogenated bisphenol A di (meth) acrylate, di (meth) acrylic acid ester of caprolactone adduct (n + m = 2-5) of bisphenol A, di (n + m = 2-5) of caprolactone adduct of hydrogenated bisphenol A Di (meth) acrylic acid esters such as di (meth) acrylic acid esters of meta) acrylic acid esters and caprolactone adducts of bisphenol F (n + m = 2-5);

Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n- Nonyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, 2-dicyclopentenoxyethyl (meth) acrylate, isobornyl ( Meta) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, methoxyethoxyethyl (meth) acrylate, ethoxyethoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2 -Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate and ethylene oxide adduct, 2 Additions of -hydroxyethyl (meth) acrylate and propylene oxide, additions of 2-hydroxyethyl (meth) acrylate and organic lactone such as addition of 2-hydroxyethyl (meth) acrylate and ε-caprolactone (meth) Acrylate;

(Meta) acrylamides such as N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide;

Polybasic acids such as phthalic acid, succinic acid, hexahydrophthalic acid, tetrahydrophthalic acid, terephthalic acid, azelaic acid, adipic acid, polyhydric alcohols such as ethylene glycol, hexanediol, polyethylene glycol, polytetramethylene glycol and (meth) ) Polyester di (meth) acrylate obtained by reaction with acrylic acid or a derivative thereof;

An organic diisocyanate is added to the hydroxyl group of an alcohol composed of one or a mixture of two or more kinds such as alcan diol, polyether diol, polyester diol, and spiroglycol, and one or more (meth) in the molecule is added to the remaining isocyanate group. Examples thereof include urethane di (meth) acrylates (excluding component (B)) obtained by reacting an acryloyloxy group and a hydroxy group-containing (meth) acrylic acid ester having one hydroxy group.

As the component (C), these compounds may be used alone or in combination of two or more.
As the component (C), dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, pentaerythritol tetraacrylate, and pentaerythritol triacrylate because the cured film has a good balance between scratch resistance and adhesion and is inexpensive and easily available. , Tris (2-hydroxyethyl) isocyanurate triacrylate, ethylene oxide 4 mol-modified bisphenol A diacrylate, tetrahydrofurfuryl acrylate are preferable, and pentaerythritol tetraacrylate and pentaerythritol further improve the balance between scratch resistance and adhesion. More preferred are triacrylate and tetrahydrofurfuryl acrylate.

The blending amount of the component (C) in the present composition is 25 to 69% by mass with respect to the total 100% by mass of the components (A) to (C). The larger the amount of the component (C), the higher the scratch resistance of the cured film, and the smaller the amount, the better the adhesion. From the viewpoint of the balance between scratch resistance and adhesion, the amount of the component (C) is preferably 40 to 60% by mass.

It is preferable to use ultraviolet rays to cure the composition. Therefore, it is appropriate to add various known photopolymerization initiators to the present composition. Specific examples of the photopolymerization initiator include benzoin, benzoin monomethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, acetophen, benzyl, benzophenone, p-methoxybenzophenone, diethoxyacetophenone, benzyl dimethyl ketal, 2,2-diethoxyacetophenone. , 1-Hydroxycyclohexylphenylketone, methylphenylglycolate, ethylphenylglycolate, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-ethylanthraquinone and other carbonyl compounds; tetramethylthiurammono Sulfur compounds such as sulfide and tetramethylthiuram disulfide; acylphosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and the like can be mentioned. These can be used alone or in combination of two or more. Among these, benzophenone and methylphenylglycolate are preferable because they are excellent in curability. Further, the blending amount thereof is preferably 0.1 part by mass or more, and more preferably 1 part by mass or more with respect to 100 parts by mass of the total amount of the components (A) to (C). Further, it is preferably 15 parts by mass or less, and more preferably 10 parts by mass or less.

The present composition may contain known photosensitizers such as methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, amyl 4-dimethylaminobenzoate, and 4-dimethylaminoacetophenone. The blending amount is preferably 0.1 part by mass or more, and more preferably 1 part by mass or more with respect to 100 parts by mass of the total amount of the components (A) to (C). Further, it is preferably 10 parts by mass or less, and more preferably 5 parts by mass or less.

The present composition may contain an organic solvent in order to adjust the viscosity. Examples of organic solvents include ketone compounds such as acetone, methyl ethyl ketone and cyclohexanone; ester compounds such as methyl acetate, ethyl acetate, butyl acetate, ethyl lactate and methoxyethyl acetate; alcohol compounds such as ethanol, isopropyl alcohol and butanol, Ether compounds such as diethyl ether, ethylene glycol dimethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether and dioxane; aromatic compounds such as toluene and xylene; aliphatic compounds such as pentane, hexane and petroleum naphtha can be mentioned. The blending amount is preferably 100 to 500 parts by mass with respect to 100 parts by mass of the total amount of the components (A) to (C).

In addition, the present composition includes leveling agents, adhesion-imparting agents, defoaming agents, anti-settling agents, lubricants, abrasives, rust preventives, antistatic agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, etc. Various additives may be blended.

This composition can be used for various purposes as a metal surface topcoat composition for providing a topcoat layer on a metal surface. In particular, it is very useful as a material for forming a top coat layer on the surface of a metal thin film layer of a metallized resin molded product. An intermediate layer called a middle coat may be provided between the top coat layer and the metal thin film layer formed by the present composition for the purpose of coloring or the like. Examples of the molded product to be subjected to this metallization treatment include molded products such as ABS resin, PC resin, AS resin, PP resin, and alloy resin of these resins. Examples of the metallization treatment method include forming a thermosetting or ultraviolet curable undercoat layer on these molded products before the metallization treatment, followed by a vacuum deposition method, an ion plating method, and a sputtering method. Examples thereof include a method of forming a metal thin film such as aluminum and tin.

Examples of the method of applying the present composition to the metal surface include brush coating, spray coating, dip coating, spin coating, flow coating and the like. The spray coating method and the flow coating method are preferable from the viewpoint of coating workability and smoothness and uniformity of the coating film.

As a method for curing the coating film of the present composition, a method of irradiating with active energy rays is preferable. Examples of the active energy ray include ultraviolet rays and electron beams. As the source of ultraviolet rays, for example, a high-pressure mercury lamp can be used. As the irradiation condition of ultraviolet rays, it is preferable that the amount of ultraviolet energy is about 500 to 4,000 mJ / cm ² . The film thickness of the cured film of the present composition is preferably 3 to 40 μm.

When an organic solvent is added to the composition, it is preferable to volatilize the solvent before irradiating it with active energy rays. In that case, it is preferable to volatilize the organic solvent at 40 to 130 ° C. for 1 to 20 minutes with an IR heater or warm air.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. In the following, all "parts" mean "parts by mass". In addition, various measurements and evaluations in Examples and Comparative Examples were carried out by the following methods.
1. 1. [Interference fringes]
The appearance of the top coat layer applied to the metal thin film layer was visually evaluated. The evaluation was judged according to the following criteria.
"◎": No interference fringes are observed.
"○": Slight interference fringes are observed.
"X": Interference fringes are clearly observed.
2. 2. [Scratch resistance]
The surface of the top coat layer applied to the metal thin film layer was rubbed with steel wool (# 0000, manufactured by Bonstar Co., Ltd.) 5 times, and the fragility was visually observed, and the hardness was evaluated according to the following criteria.
"○": There are no scars. Or there are slight scars.
"X": Scars are clearly observed.
3. 3. [Adhesion]
The adhesion between the topcoat layer and the metal thin film was evaluated by a grid peeling test. That is, a cutter knife is used to make cut grooves in the top coat layer applied to the metal thin film layer at 1 mm intervals to reach the base material, 100 1 mm ² grids are made, and cellophane tape (registered trademark) is attached onto the cut grooves. The grids that were peeled off and peeled off were counted. The evaluation was judged according to the following criteria.
"○": No peeling.
"△": Number of peels 1 to 50.
"X": Number of peels 51 to 100.
4. [Moisture resistance]
The prepared sample was placed in a wetness tester at 50 ° C. and a relative humidity of 95% for 96 hours, taken out, and then subjected to a grid peeling test by the method of 3 above to evaluate the adhesion. The evaluation was judged according to the following criteria.
"○": No peeling.
"△": Number of peels 1 to 50.
"X": Number of peels 51 to 100.

<Synthesis Example 1> [Production of Polymer (PA-1: Component A)]
1280 g of butyl acetate was placed in a 4 L four-necked flask and heated so that the internal temperature became 90 ° C. Next, the internal temperature was kept at 90 ° C. while stirring the inside of the flask, and 890 g of methyl methacrylate (Tg: 100 ° C.), 350 g of isobutyl methacrylate (Tg: 48 ° C.), 350 g of isobornyl methacrylate (150 ° C.) and polymerization were placed in the flask. A monomer-containing mixture containing 6 g of azobisisobutynitrile as a catalyst was added dropwise at a constant velocity over 4 hours. After that, 0.2 g of azobisisobutynitrile was additionally added into the flask every hour for a total of 4 times, the temperature was raised to 98 ° C. after the addition, and the mixture was stirred and cooled for 2 hours, and 1120 g of butyl acetate was added. The weight average molecular weight was obtained copolymer 5.8 × 10 ⁴ to (PA-1).

For the weight average molecular weight, after preparing a tetrahydrofuran solution (0.4% by mass) of the sample, 100 μl of the above solution was injected into a TOSO gel permeation chromatography apparatus equipped with TOSO columns (GE4000HXL and G2000HXL). , Flow rate: 1 ml / min, eluent: tetrahydrofuran, column temperature: 40 ° C., measured by gel permeation chromatography, and converted with standard polystyrene.

<Synthesis Example 2> [Production of Polymer (PA-2: Component A)]
50 copolymers (PA-2) having a weight average molecular weight of 5.8 × 10 ⁴ were prepared in the same manner as in Synthesis Example 1 except that the total amount of isobornyl methacrylate was replaced with dicyclopentanyl methacrylate (Tg: 175 ° C.). A toluene solution containing% was obtained.

<Synthesis Example 3> [Production of Polymer (PA-3: Copolymer Solution for Undercoat Material)]
The monomers to be dropped were N- (n-butoxymethyl) acrylamide (-20 ° C.) 300 g (30%), methyl methacrylate 400 g (40%) and styrene (Tg: 100 ° C.) 300 g (30%). Otherwise in the same manner as in Synthesis Example 2, the weight-average molecular weight to obtain a toluene solution containing copolymer of 3.0 × 10 ⁴ to (PA-3) 50%.

<Synthesis Example 4> [Production of Urethane Acrylate (UA: Component B)]
A 3 L four-necked flask is charged with 285 g of a bisphenol A PO adduct (trade name: ADEKA BPX-11, manufactured by ADEKA Corporation), 21 g of neopentyl glycol, 0.2 g of dibutyltin dilaurate, and 244 g of butyl acetate in a water bath. It was heated so that the internal temperature became 60 ° C.

The internal temperature was maintained at 60 ° C. while stirring the contents of the flask, and 436 g of isophorone diisocyanate was added dropwise from a dropping funnel with a side tube at a constant velocity over 2 hours, and the mixture was further stirred at the same temperature for 1 hour for reaction.
Next, the temperature of the contents of the flask was raised to 70 ° C., and 232 g of 2-hydroxyethyl acrylate charged in another dropping funnel and 1.5 g of 2,6-di-tershaributyl-4-methylphenol were uniformly mixed and dissolved. The solution was added dropwise at a constant velocity over 1 hour while maintaining the temperature inside the flask at 70 ° C. Then, the temperature of the contents of the flask was maintained at 70 ° C. and the reaction was carried out for 6 hours to produce urethane acrylate UA having a weight average molecular weight of 4,500.

<Adjustment of undercoat material>
100 copies of PA-3, DPHA (manufactured by Nippon Kayaku Co., Ltd., trade name: KAYARAD DPHA) 30 copies, EO-modified hydrogenated bisphenol A diacrylate (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name: New Frontier HBPE) -4) 10 parts, 5 parts of dicyclopentenyloxyethyl acrylate (manufactured by Hitachi Kasei Kogyo Co., Ltd., trade name: Funkryl FA-512A), 5 parts of benzophenone, 80 parts of butyl acetate and 100 parts of isobutanol are mixed. An undercoat material was produced by stirring.

<Example 1>
Next, the components shown in Table 1 were weighed in a stainless steel container and stirred for 30 minutes until the whole became uniform to prepare a metal surface topcoat composition. Next, the test piece (5 cm × 9 cm, thickness 3 mm), which is a molded product of ABS resin, was spray-coated with the above-mentioned undercoat material. Furthermore, the organic solvent is volatilized under heating conditions held in a warm air dryer at 60 ° C. for 3 minutes, and the active energy rays of 100 mW / cm ² and integrated light intensity of 1000 mJ / cm ² are irradiated in the air with a high-pressure mercury lamp. A coating film (undercoat layer) was formed so that the film thickness after curing was about 10 to 15 μm. Next, a metal thin film layer was formed by vapor deposition using a vacuum vapor deposition apparatus EBA-800 manufactured by ULVAC, Inc. so that the aluminum film thickness was 100 nm by a vacuum vapor deposition method. On the metal thin film layer, the metal surface topcoat composition was spray-coated so that the film thickness after curing was 10 to 15 μm. The organic solvent was volatilized by holding this in a warm air dryer at 60 ° C. for 3 minutes. Then, a top coat layer was formed by irradiating with an active energy ray of 100 mW / cm ² and an integrated light intensity of 1000 mJ / cm ² with a high-pressure mercury lamp. The evaluation results of the obtained samples are shown in Table 1.

<Examples 2 to 5, Comparative Examples 1 to 4>
Table 1 shows the results of preparing and evaluating samples in the same manner as in Example 1 except that the metal surface topcoat composition was prepared using the components shown in Table 1.

The abbreviations in Table 1 represent the following compounds.
-"DPHA": A mixture of dipentaerythritol hexa and pentaacrylate (trade name: KAYARAD DPHA, manufactured by Nippon Kayaku Co., Ltd.)
-"PETIA": A mixture of pentaerythritol tetra and triacrylate (trade name: PETIA, manufactured by Daicel Ornex Co., Ltd.)
-"A-9300S": Tris (2-hydroxyethyl) isocyanurate triacrylate (trade name: NK ester A-9300S, manufactured by Shin Nakamura Chemical Industry Co., Ltd.)
-"BPE-4": EO4 molar modified bisphenol A diacrylate (New Frontier BPE-4, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.)
-"THFA": Tetrahydrofurfuryl acrylate (trade name: Viscoat # 150, manufactured by Osaka Organic Chemical Industry Co., Ltd.)
・ "BP": Benzophenone (trade name: benzophenone, manufactured by Daido Kasei Kogyo Co., Ltd.)
-"MBF": Methylphenylglycolate (trade name: VICURE-55, manufactured by Showa Kosan Co., Ltd.)
-"PM-21": Phosphate group-containing methacrylate (trade name: KAYAMER PM-21, manufactured by Nippon Kayaku Co., Ltd.)
-"SH-28PA": Silicon-based leveling agent (trade name: SH-28PA, manufactured by Toray Dow Corning Co., Ltd.)
・ "Toluene": manufactured by Idemitsu Kosan Co., Ltd. ・ "Xylene": manufactured by Idemitsu Kosan Co., Ltd. ・ "Butyl acetate": manufactured by Daicel Chemical Industry Co., Ltd. ・ "Swazole # 1000": Solvent Naphtha (trade name: Swazole #) 1000, manufactured by Cosmo Matsuyama Oil Co., Ltd.

From the above results, since the metal surface topcoat composition of the example was a mixture of the component (A), the component (B) and the component (C) in a predetermined ratio, there were no interference fringes on the metal surface. It was found that a topcoat layer having an excellent balance between scratch resistance and adhesion can be formed on the metal surface. It was also found that this top coat layer has good moisture resistance and excellent durability.

On the other hand, from the comparative example, if the amount of the component (A) is small, interference fringes are observed and the adhesion is poor, if the amount of the component (A) is large, the scratch resistance is poor, and the component (B) Interference fringes were observed when the blending amount was small, and it was found that the adhesion was also poor, and that the scratch resistance was poor when the blending amount of the component (B) was large.

Claims (2)

The homopolymer is selected from the group consisting of dicyclopentanyl methacrylate, dicyclopentanyl acrylate, dicyclopentenyl methacrylate, isobornyl methacrylate, acryloyl morpholine, adamantyl methacrylate and adamantyl acrylate having a glass transition temperature of 100 ° C. or higher. A copolymer (A) containing 15 to 60% by mass of a structural unit derived from a vinyl-based monomer (a-1) having one or more ring structures, and a urethane di (meth) acrylate having a bisphenol skeleton. A metal surface topcoat composition containing each component of B) and a compound (C) having a (meth) acryloyl group other than the urethane (meth) acrylate (B), wherein the component (A), the component (B) and The component (A) is 16 to 35% by mass, the component (B) is 15 to 40% by mass, and the component (C) is 25 to 69% by mass with respect to the total 100% by mass of the component (C). ,Composition. Resin molded product A resin molded product having a metal layer and a coating layer of the metal surface topcoat composition according to claim 1 on the surface of a base material in this order.