JP3061894B2 - Coating composition and method for surface modification of resin molded article - 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 coating composition and a method for modifying the surface of a resin molded article having improved abrasion resistance and weather resistance.

[0002]

2. Description of the Related Art Polycarbonate resins are generally transparent,
Excellent performance such as easy moldability, heat resistance, impact resistance, etc.
Wide application development is in progress. However, since the surface is apt to be damaged due to insufficient surface hardness, the product yield is reduced, and the appearance is impaired, so that it is strongly required to improve the wear resistance.

Further, the polycarbonate resin has insufficient weather resistance as compared with other synthetic resins, and when used outdoors, the appearance deterioration such as a decrease in transparency, occurrence of cracks and crazing or an increase in yellowish color is remarkable. At present, it is not practical, and there is a strong demand for improvement in weather resistance. In particular, for applications such as cover lenses for automobile headlights, tail lamps, side lamp covers, and glazing materials for automobiles, there is a strong demand for improvement in both wear resistance and weather resistance.

Various proposals have been made for improving the wear resistance and weather resistance of polycarbonate resin molded articles.
Most relate to two-coat systems.

[0005] As a specific example of the two-coat system, a paint in which an ultraviolet absorber is mixed with an acrylic, melamine, urethane or silicone resin, oligomer or monomer is coated on the surface of the molded polycarbonate resin. After applying, heat or ultraviolet rays, and irradiating an active energy ray such as an electron beam to form a film, a paint composed of acrylic, melamine, urethane or silicon is applied to the surface, and heat or There is a method of forming a crosslinked cured film by irradiating active energy rays such as ultraviolet rays and electron beams. The feature of this proposal is that the undercoat layer (primer layer) absorbs ultraviolet rays and the like that cause deterioration of the resin surface, prevents peeling and electrification of the coating, and improves weather resistance.

However, a problem with the two-coat system is that the adhesiveness of the interface between the undercoat layer and the overcoat layer (cured film) is sufficiently imparted, as well as the adhesion of the undercoat layer film to the surface of the polycarbonate resin molded article. It is important that the adhesion between the layers greatly differs depending on the degree of curing of the undercoat layer film. That is, in order to satisfy both the performance of the interface adhesion and the wear resistance, it is necessary to set the degree of curing of the undercoat layer film within a certain range. In many cases, it is not easy from the aspect, and it is generally difficult to obtain a product excellent in both performances. Further, in the case of the two-coat system, not only is the processing step complicated, but also the processing time is long, which is disadvantageous economically in many cases.

The present inventors have fully recognized the problems in the case of such a two-coat system, and studied a cured film provided with abrasion resistance, abrasion resistance and weather resistance in a one-coat system. A coating composition in which a UV absorber and a specific thermoplastic resin are added to a monomer mixture containing a special multifunctional monomer is excellent in the effect of improving abrasion resistance, scratch resistance and weather resistance (Japanese Patent Laid-Open No. 56-127635)
No.). This composition was applied to the surface of a polycarbonate resin molded product, and then a cured product was formed on the surface obtained by irradiating ultraviolet light in an air atmosphere.Accordingly, in a weather resistance test such as accelerated exposure and outdoor exposure, Also had good yellowing resistance, transparency, gloss retention and the like, and were excellent in weather resistance.

[0008]

However, when a long-term exposure test is conducted, a cured film formed from the above-mentioned coating composition may show a decrease in transparency and gloss retention or yellowing. There is a need for coating compositions that can provide even higher levels of weatherability.

[0009]

The inventors of the present invention have conducted intensive studies to improve the weather resistance without lowering the abrasion resistance, and as a result, have found that a specific polyfunctional monomer is one component of the coating composition. As a result, the present inventors have found that it is possible to improve the weather resistance of an abrasion-resistant polycarbonate resin molded product, and have completed the present invention.

The gist of the present invention is as follows. 100 parts by weight of a monomer mixture having the following composition (1) pentaerythritol tri (meth) acrylate, pentaerythritol (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol At least one polyfunctional monomer selected from the group consisting of penta (meth) acrylate and dipentaerythritol hexa (meth) acrylate;
80% by weight, (2) general formula (I)

[0011]

Embedded image (In the formula, n is an integer of 1 to 8, and at least two Xs represent a CH ₂ CH—C00— group and a CH ₂ ＣC (CH ₃ ) —
COO— group, CH ₂ ＣＨCH—COO— (CH ₂ ) ₅ —OC
O- _{group, CH 2 = C (CH 3} ) -COO- (CH 2) 5 -O
It is selected from the group of CO- groups, the rest being -OH groups. 5) to 50% by weight of a polyfunctional monomer represented by
And (3) 10 to 60% by weight of a monomer having one (meth) acryloyloxy group in one molecule and having at least one of a hydroxyl group, a cyclic ether bond and a chain ether bond in the molecule, B. 3 to 35 parts by weight of an ultraviolet absorber, C.I. (Meth) acrylic acid alkyl ester polymer 0.5
D. to 10 parts by weight; A coating composition comprising 0.1 to 10 parts by weight of a photopolymerization initiator, and a coating composition comprising: The present invention relates to a method for modifying the surface of a resin molded product, which comprises forming a cured film of the above.

The A- (1) component used in the present invention, that is, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate The polyfunctional monomer selected from the group consisting of dipentaerythritol penta (meth) acrylate and dipentaerythritol hexa (meth) acrylate is excellent in polymerization activity by ultraviolet irradiation in air, And exhibit high wear resistance. One of these monomers may be used alone, or two or more thereof may be used in combination.

The proportion of the monomer used is in the range of 30 to 80% by weight, preferably 40 to 70% by weight in the monomer mixture [A]. When the amount of the monomer is less than 30% by weight, curing in an air atmosphere becomes insufficient and an uncured state is obtained, or wrinkles are generated in a cured film, transparency is reduced, and the monomer is cured. However, a cured film having sufficient abrasion resistance cannot be obtained. Conversely, when used in excess of 80% by weight,
Although the abrasion resistance and curability are improved, cracking occurs when heated at high temperatures due to the reduced flexibility of the coating, and cracks are also observed in the coating over time for weather resistance. Become like

The polyfunctional monomer A represented by the general formula (I)
The component (2) is an isocyanurate-based monomer, and specific examples include tris (acryloyloxyethyl) isocyanurate, tris (methacryloyloxyethyl) isocyanurate, and caprolactone-modified tris (methacryloyloxy). Examples include monomers such as ethyl) isocyanurate, caprolactone-modified tris (acryloyloxyethyl) isocyanurate, and bis (acryloyloxyethylhydroxyethyl) isocyanurate. One of these monomers may be used alone, or two or more thereof may be used in combination. As these monomers, those produced and commercially available by a known method can be used. For example, product name FA-7
Tris (acryloyloxyethyl) isocyanurate (manufactured by Hitachi Chemical Co., Ltd.) commercially available under the trade name 31A.

The polyfunctional monomer A- (2) has excellent polymerization activity by irradiation with ultraviolet rays in the air, and is essential for improving weather resistance without lowering the abrasion resistance of the cured film. Component. By using the component A- (2) in combination, the long-term weather resistance is improved, the transparency and gloss of the cured film are maintained, the yellowing is reduced, and the more practical cured film that can sufficiently withstand long-term exposure. Can be formed. A-
When the component (2) is used in combination, the effect of improving the heat resistance is also recognized, and no cracks are observed even in a heat test at a high temperature, and a more practical cured film can be formed.

The proportion of the monomer used is 5 to 50% by weight, preferably 10 to 40% by weight in the monomer mixture [A].
Range. When the amount of the monomer is less than 5% by weight, the effect of improving the weather resistance becomes insufficient. On the other hand, when the amount exceeds 50% by weight, the abrasion resistance of the cured film becomes insufficient, or the curability becomes insufficient. It becomes sufficient and the uncured state and the transparency are lowered.

The monomer A- (3) component having one (meth) acryloyloxy group in one molecule and having at least one of a hydroxyl group, a cyclic ether bond and a chain ether bond in the molecule is Specifically, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate,
Examples thereof include tetrahydrofurfuryl (meth) acrylate, ethoxyethyl (meth) acrylate, ethyl carbitol (meth) acrylate, tetrahydrofurfuryloxyethyl (meth) acrylate, and caprolactone-modified tetrahydrofurfuryl (meth) acrylate.

These monomers are essential components for imparting adhesion to a polycarbonate resin molded product.
It is also a component for imparting smoothness and flexibility to the cured film. Further, it is excellent in polymerization activity by ultraviolet irradiation in the air, has an effect of improving the curability of the film, and is a component necessary for forming a uniform cured transparent film without wrinkles. Among them, tetrahydrofurfuryl (meth) acrylate, tetrahydrofurfuryloxyethyl (meth) acrylate, and caprolactone-modified tetrahydrofurfuryl (meth) acrylate are preferable.
As the monomer A- (3) component, one type may be used alone,
Also, two or more kinds may be used in combination.

The proportion of the monomer used is in the range of 10 to 60% by weight, preferably 20 to 50% by weight in the monomer mixture [A]. When the amount of the monomer is less than 10% by weight, the adhesion of the cured film is insufficient, and the curability is reduced, so that the cured film is wrinkled and the transparency is insufficient. Conversely, if the amount exceeds 60% by weight, a cured film having sufficient wear resistance cannot be obtained.

The above are the essential monomers constituting the monomer mixture [A].

The component (B) of the ultraviolet absorbent used in the present invention is not particularly limited, and broadly includes light stabilizers for polymers, for example, those similar to hindered amines. It can be used as long as it is uniformly dissolved in the composition and has good weather resistance.However, from the viewpoint of good solubility in the composition of the present invention and improvement in weather resistance, benzophenones and benzophenones are preferred. An ultraviolet absorber having a maximum absorption wavelength in the range of 240 to 380 nm, which is a compound derived from a triazole, phenyl salicylate or phenyl benzoate, is preferred.

Specific examples of the ultraviolet absorber [B] include 2
-Hydroxybenzophenone, 5-chloro-2-hydroxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone,
2-hydroxy-4-n-octoxybenzophenone,
4-dodecyloxy-2-hydroxybenzophenone, 2
-Hydroxy-4-octadecyloxybenzophenone,
2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4-dimethoxybenzophenone, phenyl salicylate, p-tert-butylphenyl salicylate, p- (1,1,3,3-tetramethyl Butyl) phenyl salicylate, 3-hydroxyphenylbenzoate, phenylene-1,3-dibenzoate, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-
5-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-3,5-di-te
rt-butylphenyl) benzotriazole, 2- (2
-Hydroxy-5-tert-butylphenyl) benzotriazole, 2- (2-hydroxy-4-octyloxyphenyl) benzotriazole, and the like. These ultraviolet absorbers may be used alone or in combination of two or more.

The amount of the ultraviolet absorber [B] is preferably in the range of 3 to 35 parts by weight, more preferably 5 to 20 parts by weight, per 100 parts by weight of the monomer mixture [A]. When the amount is less than 3 parts by weight, the effect of improving the weather resistance of the abrasion-resistant polycarbonate resin molded product is not sufficient, and when the amount exceeds 35 parts by weight, the abrasion resistance of the cross-linked cured film becomes insufficient and the curing is hardened. The properties are lowered, and an uncured state or even when cured, a uniform cured film cannot be obtained.

The alkyl (meth) acrylate polymer [C] used in addition to the monomer mixture [A] is as follows:
The effect of a dispersing aid that can improve the adhesion of the coating to the substrate and reduce the uniformity of a large amount of UV absorbers in the coating without reducing the coating appearance such as transparency or smoothness of the crosslinked cured coating. It is an essential component for improving the weather resistance of a polycarbonate resin molded article having excellent wear resistance.

Although a method for improving the weather resistance of a coating by incorporating an ultraviolet absorber in a coating material is known, a large amount of a composition for forming a coating having a highly crosslinked structure as in the present invention is contained in the composition. It was not possible to disperse the UV absorber. That is, even if a large amount of an ultraviolet absorber is added to the coating composition, a large amount of the ultraviolet absorber is not sufficiently uniformly held in the crosslinked cured film during curing of the coating composition,
Either it aggregates in the form of fine islands in the crosslinked cured film or leaches out on the surface of the cured film, and the entire film becomes milky white or the surface hardness and wear resistance of the cured film are extremely reduced.

In fact, the crosslinked cured film formed from the monomer mixture [A] of the present invention also contains only a small amount of an ultraviolet absorber. If a large amount of the ultraviolet absorber is added in excess of this amount, various defects as described above occur, and if the addition amount of the ultraviolet absorber is reduced, the above-mentioned problems are eliminated, but the weather resistance is reduced. The improvement effect becomes insufficient.

However, it has been found that the above problems can be solved at once by adding a small amount of the above-mentioned alkyl (meth) acrylate polymer [C] to the coating composition of the present invention.

The (meth) acrylic acid alkyl ester polymer [C] used in the present invention has an intrinsic viscosity [η] (g / l) of 0.01 as a standard of the average molecular weight of the polymer.
It is in the range of ~ 0.30, and is preferably selected from a homopolymer of a monomer selected from alkyl (meth) acrylates having an alkyl group having 1 to 8 carbon atoms or a copolymer thereof. . When the intrinsic viscosity [η] of the (meth) acrylic acid alkyl ester polymer [C] is less than 0.01, the (meth) acrylic acid alkyl ester polymer [C]
When the dispersing effect of the ultraviolet absorbent [B] in the crosslinked cured film is not sufficient, and when it exceeds 0.30,
The solubility of the alkyl (meth) acrylate polymer [C] in the coating composition of the present invention may be insufficient, or the smoothness of the cured film may be reduced. Also, when the alkyl group has 9 or more carbon atoms, the solubility of the (meth) acrylic acid alkyl ester polymer [C] in the coating composition becomes poor, and the smoothness and abrasion resistance of the cured film decrease. Or you may.

Specific examples of the alkyl (meth) acrylate ester polymer [C] include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and i-butyl (meth) acrylate. ) Acrylate, amyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, 2-ethyl-1-hexyl (meth) acrylate, 3-pentyl acrylate, 3-methyl-
Examples thereof include homopolymers of 1-butyl acrylate, 2-ethyl-1-butyl allylate, and 2-heptyl acrylate, and copolymers thereof. One of these polymers may be used alone, or two or more thereof may be used in combination.

The compounding amount of the alkyl (meth) acrylate ester polymer [C] to 100 parts by weight of the monomer mixture [A] is 0.5 to 10 parts by weight, preferably 1 to 6 parts by weight. is there. If the amount is less than 0.5 part by weight, a large amount of the ultraviolet absorber cannot be contained, and
When the amount exceeds 0 parts by weight, the smoothness and abrasion resistance of the crosslinked cured film are reduced.

When an ultraviolet ray is used as the active energy ray, it is preferable to add a photopolymerization initiator [D] to the monomer mixture [A], and a specific example of these compounds is benzoin. , Benzoin methyl ether,
Benzoin ethyl ether, benzoin propyl ether, benzoin isobutyl ether, acetoin, butyroin, toluoin, benzyl, benzophenone, p-
Methoxybenzophenone, 2,2-diethoxyacetophenone, α, α-dimethoxy-α-phenylacetophenone, methylphenylglyoxylate, ethylphenylglyoxylate, 4,4′-bis (dimethylaminobenzophenone), 2-hydroxy- 2-methyl-1-
Carbonyl compounds such as phenylpropan-1-one,
Sulfur compounds such as tetramethylthiuram monosulfide and tetramethylthiuram disulfide, azo compounds such as azobisisobutyronitrile and azobis-2,4-dimethylvaleronitrile, benzoyl peroxide, ditertiary butyl peroxide And acylphosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

The amount of the photopolymerization initiator [D] to be added is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the monomer mixture [A]. And the like, or a decrease in weather resistance is not preferred, and when the addition amount is too small, curing by ultraviolet rays becomes poor.

The above are essential components constituting the present invention. The coating composition can be applied easily, and the coating can be smooth and uniform.
From the viewpoint of improving the adhesion to the substrate, it is preferable to apply using an appropriate organic solvent.

Specific examples of the organic solvent include alcohols such as ethanol, isopropyl alcohol, normal-propyl alcohol, iso-butyl alcohol and normal-butyl alcohol; aromatic hydrocarbons such as benzene, toluene and xylene; Ketones such as acetone and methyl ethyl ketone, ethers such as dioxane, esters such as ethyl acetate, n-butyl acetate and iso-amyl acetate, polyhydric alcohol derivatives such as methyl cellosolve, ethyl cellosolve and butyl cellosolve, methoxybutanol and methoxypropanol Is mentioned. One of these organic solvents may be used alone, or two or more thereof may be used in combination.

The amount of the organic solvent used is in the range of 10 to 2,000 parts by weight based on 100 parts by weight of the monomer mixture [A]. If the amount of the organic solvent is less than 10 parts by weight, the coating may not have excellent smoothness and uniformity, and if it exceeds 2000 parts by weight, the thickness of the coating may be too thin. It is too much, and the wear resistance and weather resistance may decrease.

If necessary, monomers other than the monomer mixture [A] component (UV, EB curing handbook-raw material edition / Polymer Publishing Association); light stabilizers (for example, hindered amines); Agents, stabilizers such as thermal polymerization inhibitors, leveling agents, defoamers, thickeners, antistatic agents, surfactants such as antifoggants, etc. may be appropriately blended and used in the present coating composition. Good.

As a method of applying the coating composition of the present invention to, for example, the surface of a molded article of a polycarbonate resin, a method such as brush coating, flow coating, spray coating, spin coating or dip coating is employed. The dip coating method is preferred from the viewpoint of the coating workability, the smoothness and uniformity of the coating, and the spray coating method is particularly preferred from the viewpoint of the shape dependency of the molded article.

After the coating composition is applied to the surface of the polycarbonate resin molded article, the coating is set at a temperature in the range of room temperature to 120 ° C. for a time in the range of 1 minute to 60 minutes for the purpose of improving the adhesion and smoothness of the coating. You can do it.

The coating amount of the coating composition is preferably such that the thickness of the cured film is in the range of 1 to 30 μm, preferably 3 to 10 μm. When the film thickness is less than 1 μm, sufficient surface hardness, abrasion resistance, and scratch resistance cannot be obtained. When the film thickness is more than 30 μm, adhesion to a base material is reduced, and cracks are easily generated in the coating. Or

As a means for curing the coating applied to the surface of the polycarbonate resin molded article, a known method of irradiating active energy rays such as α, β and γ rays may be used, but the coating composition of the present invention is cured. It is preferable to use an ultraviolet ray as a means for causing this. As a light source for generating ultraviolet light, an ultraviolet lamp is generally used in terms of practicality and economy, and specific examples include a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, and a metal halide lamp. Can be

Regarding the atmosphere for ultraviolet irradiation, the irradiation in an inert gas such as nitrogen, carbon dioxide, argon or the like is of course acceptable, but the monomer mixture [A] of the present invention can be efficiently cured even in ordinary air. This is the most economically preferable method.

The coating composition of the present invention can be used to produce a polycarbonate resin molded article having excellent surface properties such as abrasion resistance and weather resistance, but other synthetic resin molded articles such as thermoplastic resin , Regardless of the thermosetting resin, various synthetic resin molded products, specifically, polymethyl methacrylate resin, polyallyl diglycol carbonate resin,
Sheet-like molded products and film-shaped molded products made from polystyrene resin, acrylonitrile-styrene copolymer resin (AS resin), polyvinyl chloride resin, acetate resin, ABS resin, polyester resin, polymethacrylimide resin, polyamide resin, etc. Abrasion resistance, light resistance, and the like can also be imparted to rod-shaped molded products and various injection molded products.

As polycarbonate resin molded products, various molded products molded from polycarbonate resins such as bisphenol-type polycarbonate, aliphatic polycarbonate and diethylene glycol bisallyl carbonate, for example, injection molded products such as head lamp lenses for automobiles,
It is widely used taking advantage of its excellent properties such as impact resistance, heat resistance and transparency. However, as a disadvantage, the surface hardness and weather resistance are insufficient, and improvement of these properties is strongly demanded. By using the coating composition of the present invention, a polycarbonate resin molded article having excellent wear resistance and weather resistance is provided. Can be obtained.

[0044]

The present invention will be described in more detail with reference to the following examples. The evaluation in the examples was performed by the following method.

1. Wear resistance and abrasion resistance # 000 steel wool (manufactured by Nippon Steel Wool Co., Ltd., Bonstar (trade name)) was mounted on a 25φ circular pad, and the pad was placed on the surface of a sample held on a reciprocating abrasion tester table. Was placed and subjected to 50 reciprocal scratches under a load of 1000 g. The sample was washed with a neutral detergent, and the haze was measured using a haze meter. Abrasion resistance and abrasion resistance are represented by (haze value after abrasion-haze value before abrasion).

2. Adhesiveness 11 vertical and horizontal scratches on the sample surface with a razor.
Insert at intervals of 5 mm, make 100 squares, and press cellophane tape (width 25 mm, made by Nichiban Co.) against the squares and remove it sharply upward. The evaluation of the adhesion is shown by the number of remaining stitches / the total number of stitches (100).

3. Appearance (1) Transparency Shown as haze (%) using a haze meter.

(2) Cracks Observed visually, and the following criteria were used.

…: No cracks generated Δ: slight cracks generated ×: countless cracks generated (3) Yellow band color computer (manufactured by Suga Test Instruments Co., Ltd., SH-
Displayed in yellow degree (Y · I) using 4).

4. The weather resistance was tested using a sunshine carbon weather meter (WEL-SUN-DC type, manufactured by Suga Test Instruments Co., Ltd.). Test conditions: Black panel temperature 63 ± 3 ° C, rainfall 1
A 2 minute / 60 minute cycle. After the test, the appearance (transparency, crack and Y · I) was evaluated according to Section 3.

5. Heat resistance The sample was left in an atmosphere of 120 ° C. to 150 ° C. for 1 hour, taken out, and then observed for appearance (cracks).

Embodiments 1-3. Comparative Examples 1 to 3 The coating compositions shown in Table 1 were prepared and applied to a 3 mm-thick injection molded plate (manufactured by General Electric, trade name; Lexan LS-2, color tone: 111) by a spray coating method. And left at 40 ° C. for 5 minutes. Then, in an air atmosphere, a high-pressure mercury lamp (manufactured by Eye Graphics, output: 120 W / cm)
^{Using 2} ), the composition was cured under the condition that the total irradiation amount of ultraviolet rays was 2500 mj / cm ² (wavelength 340 nm to 380 nm). The film thickness at this time was 5 microns. Table 1 shows the obtained results.

[0053]

[Table 1] DPHA: dipentaerythritol hexaacrylate FA-731A: tris (acryloyloxyethyl)
Isocyanurate, manufactured by Hitachi Chemical Co., Ltd. M-325: Caprolactone-modified tris (acryloyloxyethyl) isocyanurate, manufactured by Toagosei Co., Ltd. M-215: bis (acryloyloxyethylhydroxyethyl) isocyanurate, Toagosei Co., Ltd. THF-A: Terolahydrofurfuryl acrylate (meth) acrylic acid alkyl ester polymer: polyethyl methacrylate, intrinsic viscosity [η] 0.09 (g /
l) BIP: benzoin isopropyl ether BNP: benzophenone UV-A: 2- (hydroxy-5-tert-butylphenyl) benzotriazole, trade name Tinuvin-P
S (manufactured by Ciba-Geigy) UV-A: 2,4-dihydroxybenzophenone, trade name Biosorb 100 (manufactured by Kyodo Yakuhin).

Examples 4 and 5, Comparative Examples 4 and 6 The coating compositions shown in Table 2 were prepared. Using this, processing was carried out according to Examples 1 to 3. The film thickness at this time was 5 microns. Table 2 shows the obtained results.

[0055]

[Table 2]

[0056]

The polycarbonate resin molded article produced by using the coating composition of the present invention is excellent not only in abrasion resistance and weather resistance but also in adhesion and durability to a substrate. For example, it is applied to applications such as head lamp lenses for automobiles and is extremely useful, and its industrial value is great.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takashi Kawaguchi 4-160 Sunadabashi, Higashi-ku, Nagoya City, Aichi Prefecture Inside Mitsubishi Rayon Co., Ltd. Product Development Laboratory (72) Inventor Osamu Takemoto 4-chome Sunadabashi, Higashi-ku, Nagoya City, Aichi Prefecture No. 1-60 Mitsubishi Rayon Co., Ltd. Product Development Laboratory (56) References JP-A-63-86763 (JP, A) JP-A-2-173163 (JP, A) JP-A-59-93733 (JP, A) JP-A-1-180338 (JP, A) JP-A-64-31811 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 4/02 C08J 7/04 C09D 4 / 00 CA (STN) CAOLD (STN) REGISTRY (STN)

Claims (2)

(57) [Claims] 1. A. First Embodiment Monomer mixture 10 having the following composition
0 parts by weight (1) Pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate and dipentaerythritol 30 to 80% by weight of at least one polyfunctional monomer selected from the group consisting of pentaerythritol hexa (meth) acrylate (2) (In the formula, n is an integer of 1 to 8, and at least two X's represent a CH ₂ ＣＨCH—COO— group and a CH ₂ ＣC (CH ₃ ) —
COO— group, CH ₂ ＣＨCH—COO— (CH ₂ ) ₅ —OC
O- _{group, CH 2 = C (CH 3} ) -COO- (CH 2) 5 -O
It is selected from the group of CO- groups, the rest being -OH groups. 5) to 50% by weight of a polyfunctional monomer represented by
And (3) a monomer 10 having one (meth) acryloyloxy group in one molecule and having at least one of a hydroxyl group, a cyclic ether bond and a chain ether bond in the molecule.
~ 60% by weight, B. 3 to 35 parts by weight of an ultraviolet absorber, C.I. (Meth) acrylic acid alkyl ester polymer 0.5
D. to 10 parts by weight; 0.1 to 10 parts by weight of a photopolymerization initiator 2. The coating composition according to claim 1, which is applied to the surface of a polycarbonate resin molded product and irradiated with ultraviolet rays to form a cured film having a thickness of 1 to 30 microns on the surface of the polycarbonate resin molded product. Surface reforming method for resin molded products.