JP3197918B2 - Coating composition and surface modification method of synthetic 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 a coating composition capable of forming an abrasion-resistant and abrasion-resistant cured film and a method for modifying the surface of a wear-resistant synthetic resin molded article using the same.

[0002]

2. Description of the Related Art Synthetic resin molded articles such as polymethyl methacrylate resin, polycarbonate resin and polyarylate resin are not only lightweight and excellent in impact resistance, but also inexpensive and easy to mold, as compared with glass. And has been widely used in many fields by taking advantage of these advantages. For example, it is used as a glazing material for automobiles, buses, aircraft, and the like, or as lenses such as headlamp lenses and corner lenses, as well as lenses for spectacles and optical devices.

[0003] However, these synthetic resin molded products have insufficient surface hardness, so that the surface of the molded product is brought into contact with other objects, impact, scratching, etc. during transportation of the molded product, mounting of parts, or use. They may be damaged, resulting in reduced product yields or poor aesthetics.

[0004] Therefore, there is a strong demand for improving the surface hardness of these synthetic resin molded articles, and many methods for improving the surface hardness have been conventionally proposed. For example, a coating composed of a partially condensed reaction product of a silane mixture containing alkyltrialkoxysilane as a main component and colloidal silica is applied to the surface of a molded article, and then this is subjected to a heat treatment to form a cured film and improve abrasion resistance. How to improve,
A coating mainly composed of a polyfunctional acrylate having two or more (meth) acryloyloxy groups in one molecule is applied to the surface of the molded article, and then irradiated with ultraviolet rays to form a cured film and improve abrasion resistance. A method of doing so has been proposed.

[0005] The former is an excellent method because it has a large effect of improving abrasion resistance, but requires a primer coating treatment due to poor adhesion to a molded product, which increases the cost and complicates the treatment process. I do. Further, since the heat treatment requires a long time, there is a difficulty in productivity.

[0006] The latter is a process having an extremely short curing time of several seconds to several tens of seconds due to the ultraviolet curing method and excellent in productivity. In recent years, a method that can be cured even in the air has been proposed, and it can be said that this method is extremely economically useful. However, the latter ultraviolet curing method tends to have a lower abrasion resistance level than the former thermosetting method, and it is known that the abrasion resistance level is clearly lower especially when the wear material is abrasive. I have.

[0007] Japanese Patent Publication No. 57-500984 discloses an ultraviolet-curable silicone coating material composition that makes use of the advantages of both methods. By using ultraviolet rays for curing, the curing time, which was a fundamental problem of silicon-based coating materials, can be greatly reduced, and curing can be performed in a short time of several seconds to several minutes, which has an advantage in terms of productivity. Is recognized.

[0008]

However, the above-mentioned coating composition has a problem that it is impossible to achieve both the improvement of the abrasion resistance of the cured coating and the improvement of the adhesion of the coating to the surface of the molded article. It has been found. That is, this composition is composed of an ultraviolet-curable acrylic component and a colloidal silica-combined silicon component. Although the adhesion of the coating is improved when the acrylic component is increased, the wear resistance of the cured coating is increased by increasing the acrylic component. Drops.
In particular, a decrease in surface wear resistance due to abrasive grains tends to be significant due to an increase in the acrylic component.

Conversely, when the silicon content increases, the abrasion resistance of the cured coating is improved, but the adhesion of the coating to the molded article is reduced, and the initial adhesion is not only reduced, but also with the thermal cycle test and the high temperature. -Adhesion problems will occur in tests under severe environmental conditions, such as tests under high humidity, and furthermore, such as weather resistance tests.

[0010]

Means for Solving the Problems In view of the above-mentioned problems, the present inventors have conducted intensive studies on the compatibility between the wear resistance of a cured film and the adhesion to a molded product. The inventors have found that the above-mentioned problems can be solved by forming a coating composition using an acrylic polymer as a crosslinked cured film on the surface of a synthetic resin molded article, and have completed the present invention.

That is, the present invention provides (a) a primary particle size of 1 to
Colloidal silica composed of 200 nm silica particles 5
80% by weight, (b) the following general formula (I)

[0012]

Embedded image (Where X is CH ₂ ＝ CH—COO—, CH ₂ ＣC (CH
₃₎ -COO- or CH ₂ = CH- group, R ¹ is a single bond or
A divalent hydrocarbon group, R ² and R ³ are a monovalent hydrocarbon group, a
Represents an integer of 1 to 3, b represents an integer of 0 to 2, and a + b represents an integer of 1 to 3. 5) to 80% by weight of a hydrolysis or condensation reaction product of one or more of the monomers represented by

(C) 10 to 90% by weight of a structural unit derived from an alkyl ester of acrylic acid and / or methacrylic acid having 1 to 8 carbon atoms, and a hydroxyl value of 10 to 300 mgK
A coating composition comprising 1 to 30% by weight of an OH / g acrylic copolymer and (d) 0.1 to 5% by weight of an ultraviolet-sensitive photoinitiator.

Another aspect of the present invention is characterized in that the above-mentioned coating composition is applied to the surface of a synthetic resin molded product, and a cross-linked cured film is formed on the surface of the synthetic resin molded product by irradiating ultraviolet rays. This is a method for modifying the surface of a synthetic resin molded product.

[0015]

The primary particle size used in the present invention is 1 to 200 nm.
Colloidal silica (a) component comprising silica particles of
Ultrafine particles of silicic anhydride were made into a colloidal solution. Further, colloidal silica in a powder form containing no dispersion medium can also be used. Examples of the dispersion medium of colloidal silica include water; alcohols such as methanol, ethanol, iso-propanol, n-butanol, and n-propanol; polyhydric alcohols such as ethylene glycol; polyhydric alcohol derivatives such as ethyl cellosolve and butyl cellosolve; Ketones such as methyl ethyl ketone, methyl isobutyl ketone, and diacetone alcohol; monomers such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and tetrahydrofurfuryl acrylate; and general organic solvents are particularly preferred in the present invention. It is preferable to use alcohols having 1 to 4 carbon atoms.

As these colloidal silicas, commercially available ones manufactured by a known method can be used. It is necessary to use particles having a particle size of 1 to 200 nm , particularly preferably 5 to 80 nm . Particle size is 1 n
If it is less than m , it is difficult to obtain a stable dispersion due to poor stability of the dispersion state, and if it is more than 200 nm , the transparency of the coating film becomes poor, and only a highly turbid product can be obtained. .

Although colloidal silica is available in an acidic or basic form, it is more preferable to use an acidic form in the present invention.

Colloidal silica is a hard coating having abrasion resistance,
It significantly improves the surface hardness and exhibits an excellent effect particularly in an abrasion test using abrasive grains as an abrasive. However, when a film is formed by using colloidal silica alone, the adhesion to the surface of the molded article is extremely poor, so that the film is cracked or the film peels off, so that it cannot be used alone. The mixing ratio of colloidal silica is 5 to 80% by weight, preferably 1 to 80% by weight in the coating composition.
It is 0 to 70% by weight, more preferably 20 to 65% by weight. When the compounding ratio is less than 5% by weight, the abrasion resistance of the cured film is insufficient. On the contrary, when the compounded amount is more than 80% by weight, cracks are generated in the cured film and adhesion is lowered. Become. The use ratio of colloidal silica indicates a value converted as a solid content of silica particles.

In the present invention, a hydrolysis or condensation reaction product (b) of one or more monomers represented by the above general formula (I) (hereinafter abbreviated as silica-based condensation polymer) is used.

Examples of the monomer represented by the general formula (I) include β-acryloyloxyethyltrimethoxysilane, β-acryloyloxyethyltriethoxysilane, γ-acryloyloxypropyltrimethoxysilane, γ-acryloyloxypropyl Triethoxysilane, β-acryloyloxyethylmethyldimethoxysilane, β-acryloyloxyethylmethyldiethoxysilane, γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropylmethyldiethoxysilane, β-acryloyloxyethylethyldimethoxysilane , Β-acryloyloxyethylethyldiethoxysilane, γ-acryloyloxypropylethyldimethoxysilane, γ-acryloyloxypropylethyldiethoxysila , Β-methacryloyloxyethyltrimethoxysilane, β-methacryloyloxyethyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltriethoxysilane, β-methacryloyloxyethylmethyldimethoxysilane, β-methacryloyloxy Ethylmethyldiethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, γ
-Methacryloyloxypropylmethyldiethoxysilane, β-methacryloyloxyethylethyldiethoxysilane, β-methacryloyloxyethylethyldimethoxysilane, γ-methacryloyloxypropylethyldiethoxysilane, γ-methacryloyloxypropyldiethoxysilane, γ-methacryloyl (Meth) acryloyloxy-functional silanes such as oxypropyldimethoxysilane; vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane.

[0021]

The silica-based polycondensate (b) is prepared by adding one or more of these monomers together with water in the presence of an effective amount of a hydrolysis catalyst such as hydrochloric acid at a temperature from room temperature to reflux temperature in the range of about 1-1.
It can be obtained by a conventional method such as stirring for 0 hour.

The proportion of the silica-based condensation polymer (b) used in the coating composition is 5 to 80% by weight, preferably 10 to 80% by weight.
It is 70% by weight, more preferably 15 to 65% by weight.
When the use ratio is less than 5% by weight, the abrasion resistance of the cured film becomes insufficient, the film is cracked or turbid, and a processed product having good appearance cannot be obtained. Conversely, if it exceeds 80% by weight, the curability becomes insufficient and the abrasion resistance is disadvantageous.

The proportion of the silica-based polycondensate (b) used herein indicates the weight of the product of the hydrolysis and condensation reaction, and includes alcohol, water, and other volatile substances by-produced in the course of the reaction. It does not contain any components.

The structural unit derived from the alkyl ester of (meth) acrylic acid having 1 to 8 carbon atoms used in the present invention is 10 units.
-90% by weight, and the hydroxyl value is 10-300 mgKOH /
g of the acrylic copolymer (c) is obtained by copolymerizing an alkyl ester of (meth) acrylic acid having 1 to 8 carbon atoms and an α, β-ethylenically unsaturated monomer having a hydroxyl group as essential components. Copolymer.

Examples of the alkyl ester of (meth) acrylic acid having 1 to 8 carbon atoms include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate,
T-butyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-methacrylate
And butyl and 2-ethylhexyl methacrylate.

As the α, β-ethylenically unsaturated monomer having a hydroxyl group, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, acrylic acid 2-hydroxybutyl, methacrylic acid 2
Monomers such as -hydroxybutyl, 4-hydroxybutyl acrylate, and 4-hydroxybutyl methacrylate can be mentioned as typical examples.

The acrylic copolymer is composed of acrylic acid, methacrylic acid, itaconic acid,
Fumaric acid, unsaturated acids such as maleic anhydride, (meth) acrylates such as cyclohexyl acrylate, cyclohexyl methacrylate, stearyl methacrylate,
One or two or more monomers such as aromatic vinyl compounds such as styrene, α-methylstyrene and vinylpyridine may be copolymerized.

The acrylic copolymer can be produced by copolymerizing a predetermined ratio of a monomer mixture by a conventional method such as solution polymerization, suspension polymerization, emulsion polymerization, or bulk polymerization. Is obtained by a solution polymerization method in which a polymerization initiator and a chain transfer agent are allowed to act on a monomer mixture in the presence of an organic solvent such as xylene, toluene, ethyl acetate, n-butyl acetate, methyl ethyl ketone, or ethylene glycol monoethyl ether acetate. Acrylic copolymers are preferred. The molecular weight of the acrylic copolymer is preferably about 10,000 to about 100,000 in terms of weight average molecular weight. The use of the alkyl ester of (meth) acrylic acid having 1 to 8 carbon atoms in the alkyl group in the range of 10 to 90% by weight in the monomer mixture can improve the compatibility stability of the coating composition and the transparency of the cured film. It is indispensable from the viewpoint of properties and abrasion resistance. When this condition is not satisfied, the film becomes turbid and has poor transparency, so that it is difficult to form a practical film.

As a component to be copolymerized with the alkyl ester of (meth) acrylic acid, an α, β-ethylenically unsaturated monomer having a hydroxyl group, for example, 2-hydroxyethyl methacrylate is an essential component. This monomer is used in such an amount that the resulting copolymer has a hydroxyl value of 10 to 300 mgKOH / g, preferably 20 to 250 mgKOH / g. When the hydroxyl value is less than 10 mgKOH / g, the adhesion of the cured film to the surface of the molded product becomes insufficient, or the film becomes cloudy and the transparency decreases. Conversely, if it exceeds 300 mgKOH / g, the abrasion resistance of the cured film is undesirably reduced.

When the acrylic copolymer (c) is used in combination with the colloidal silica (a) and the silica-based condensed polymer (b), the surface of the molded article can be reduced without reducing the abrasion resistance of the cured film. It has become possible to greatly improve the adhesion of the coating to the film. The cured film formed only from the component (a) and the component (b),
Adhesion after a hot water test or a thermal cycle test is insufficient, and it is difficult to form a practical film. On the other hand, when the component (c) is used together, the durable adhesiveness is also improved, so the use of the component (c) is essential.

The mixing ratio of the acrylic copolymer (c) is as follows:
1 to 30% by weight in the coating composition, preferably 3 to
It is 25% by weight, particularly preferably 5 to 20% by weight. If the use ratio is less than 1% by weight, the adhesion becomes insufficient, and if it exceeds 30% by weight, the abrasion resistance decreases, which is not preferable.

Means for applying the coating composition of the present invention to the surface of a synthetic resin molded article and then curing the formed film include the following curing catalyst in the coating composition, for example, ammonium perchlorate. , Perchloric acid, hydrochloric acid, paratoluenesulfonic acid, sodium acetate, tetrabutoxy titanium,
Using a well-known compound such as n-butylamine, it is possible to bake at a temperature lower than the deformation temperature of the molded article (about 130 ° C.) for 20 minutes to 5 hours, but in the case of the present invention, the ultraviolet-sensitive photoinitiator is used. The method of irradiating and curing by using ultraviolet rays is a particularly preferable method in terms of productivity and economy. Also,
The coating may be cured by irradiating active energy rays such as α-rays, β-rays and γ-rays having the same effect as ultraviolet rays.

When ultraviolet rays are used as a means for curing the coating,
The ultraviolet-sensitive photoinitiator (d) component in the coating composition
Is suitable in terms of curability and uniformity of the coating.
It is. The component (d) is not particularly limited.
Uniformly dissolved in the coating composition of the present invention,
If the ratio is high and the cured film does not cause coloring, use
Can be used. UV-sensitive photoinitiator (d)
For example, benzophenone, benzoin methyl ether
Benzoin ethyl ether, benzoin isopropyl
Ether, benzoin isobutyl ether, benzene
, Diethoxyacetophenone, methylphenylglio
Xylate, 2-hydroxy-2-methyl-1-phenyl
Lupropan-1-one, 1-hydroxycyclohexyl
Phenyl ketone, benzyl dimethyl ketal, 2,4
6-trimethylbenzoyldiphenylphosphine oxa
And a radical-type initiator such as the following general formula (R⁷ -C₆ H_Four )_e X⁺MQ_f ^- (III) (wherein X is an atom selected from I, P and S;
Is metal or metalloid, Q is selected from Cl, F, Br and I
Which is represented by R⁷ Is hydrogen or carbon number 1-12
Is a monovalent hydrocarbon group, e is an integer of 2 or 3,
f is an integer of 4 to 6. Cation type start
Agents can be mentioned. M represented by the general formula (III)
Q_f ^-Is any kind of ionic species, preferably SbF
₆ ^-, AsF ₆ ^-, BF_Four ^-And PF₆ ^-Is selected from Click
Specific examples of the on-type initiator include tetrafluoroborane
Acid, hexafluorophosphoric acid, hexafluoroarsenic acid and
Diphenyliodonium of xafluoroantimonic acid
Salts: tetrafluoroboric acid, hexafluorophosphoric acid, f
Xafluoroarsenic acid and hexafluoroantimonic acid
Liphenylsulfonium salts and the like can be mentioned.

The radical initiator and the cationic initiator may be used alone or in combination. Further, the radical type initiator and the cationic type initiator may be used in combination of two or more of the same type.

The proportion of the ultraviolet-sensitive photoinitiator (d) used is 0.1 to 5% by weight in 100% by weight of the coating composition. If the use ratio is less than 0.1% by weight, the curability is insufficient, so that a uniform cured film cannot be formed, or if the use ratio exceeds 5% by weight, the cured film is colored. Sometimes.

The coating composition of the present invention may contain, if necessary, an organic solvent, a monomer other than the component (b), for example, a monomer having one (meth) acryloyloxy group in one molecule,
A polymerizable monomer such as a polyfunctional monomer having two or more (meth) acryloyloxy groups in one molecule; a stabilizer such as an ultraviolet absorber, an antioxidant, and a thermal polymerization inhibitor; a leveling agent; Surfactants such as an antifoaming agent, a thickener, an antisettling agent, a pigment dispersant, an antistatic agent, and an antifogging agent; a curing catalyst selected from acids, alkalis, salts, and the like may be appropriately blended and used. Good.

The organic solvent is used in combination with the uniform solubility and dispersion stability of the coating composition, the adhesion to the molded product, the smoothness and uniformity of the coating, and the like. The organic solvent is not particularly limited as long as it can exhibit the above performance. Specific examples of the organic solvent include alcohols such as ethanol, i-propyl alcohol, n-propyl alcohol, i-butyl alcohol and n-butyl alcohol, aromatic hydrocarbons such as benzene, toluene and xylene, and acetone. And ketones such as methyl ethyl ketone, ethers such as dioxane, esters such as ethyl acetate, n-butyl acetate and iso-amyl acetate, and polyhydric alcohol derivatives such as methyl cellosolve, ethyl cellosolve and butyl cellosolve. One of these organic solvents may be used alone,
Also, two or more kinds may be used in combination.

For the purpose of improving the weather resistance, it is preferable to use an ultraviolet absorber or a hindered amine light stabilizer, or to use both of them. By using these, the weather resistance of the obtained film, for example, yellowing resistance of the film due to exposure,
Retention of gloss and transparency, resistance to cracking or adhesion to a synthetic resin molded article substrate, etc. are further improved.

The ultraviolet absorbent used in the present invention is not particularly limited, and any ultraviolet absorbent which can be uniformly dissolved in the coating composition and has good weather resistance can be used. From this point, an ultraviolet absorber derived from a benzophenone-based, benzotriazole-based, phenyl salicylate-based, phenyl benzoate-based, or cyanoacrylate-based compound and having a maximum absorption wavelength in the range of 240 to 380 nm is preferred. Especially when the synthetic resin molded product is polycarbonate resin, prevention of deterioration of the molded product surface,
For example, the blending of an ultraviolet absorber is particularly preferred for improving yellowing resistance and the like.

As a method of applying the coating composition of the present invention to, for example, the surface of a synthetic resin molded product, 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 of the composition for application, the smoothness and uniformity of the coating, the adhesion of the coating to the substrate, and the spray coating method is particularly preferred from the viewpoint of applicability to the shape of the molded article. .

The coating amount of the coating composition is preferably such that the cured film has a thickness 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 the 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 synthetic resin molded product, a method of irradiating active energy rays such as α, β and γ rays can be applied, but the coating composition of the present invention is cured. It is preferable to use ultraviolet rays as a means. As a light source for generating ultraviolet light, an ultraviolet lamp is 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. As the exposure atmosphere of the ultraviolet irradiation, an inert gas such as nitrogen, carbon dioxide, argon gas or the like may be used, or a normal air atmosphere may be used. In addition, before the coating applied to the surface of the synthetic resin molded product is cured with ultraviolet rays, an infrared ray or a hot air drying furnace is used at a temperature range of 20 ° C. to 120 ° C. for 1 minute to improve adhesion of the coating. A heat treatment for 60 minutes may be performed.

In the present invention, the synthetic resin molded article used for producing a synthetic resin molded article having excellent abrasion resistance and abrasion resistance is not limited to thermoplastic or thermosetting resin, and various synthetic resin molded articles, for example, Sheet-shaped molding manufactured from polymethyl methacrylate resin, polycarbonate resin, polyallyl diglycol carbonate resin, polystyrene resin, acrylonitrile-styrene copolymer resin, ABS resin, polyester resin, polyacrylate resin, polyamide resin, polymethacrylimide resin, etc. Products, film-shaped products, rod-shaped products and various injection-molded products. Among these molded products, molded products manufactured from polymethyl methacrylate resin, polycarbonate resin, polymethacrylimide resin, etc. are often used taking advantage of properties such as optical properties, heat resistance and impact resistance. These molded articles are particularly preferable as synthetic resin molded articles used in the present invention, because they are strongly required to improve abrasion resistance, scratch resistance, durability, and weather resistance.

[0045]

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. In the examples, “parts” and “%” are based on weight. 1. Abrasion resistance and abrasion resistance (1) Steel wool abrasion test # 000 steel wool (Nippon Steel Wool Co., Ltd. product, Bonstar R attached to a 25φ circular pad, sample surface held on a reciprocating abrasion tester table) The sample was washed 100 times under a load of 1000 g by reciprocating abrasion, and the sample was washed with a neutral detergent and measured for haze using a haze meter. (2) Taber abrasion test The Taber abrasion test was performed in accordance with ASTM D. 1044.
Under the conditions of 10F, a load of 500 g, and a wear frequency of 300 cycles, the haze value is shown in the same manner as in the steel wool scratch test. 2. Adhesiveness 11 vertical and horizontal 1.5 mm razors on the sample surface
Scratches reaching the base material of the molded product are made at intervals, and 100 squares are made, and cellophane tape (25 mm wide, manufactured by Nichiban)
Is pressed against the eye and rapidly removed upward. The evaluation of the adhesion was performed as follows.

(3) When the same location was tested three times, no peeling was observed.

△: When the same location was tested three times, less than 50 squared peelings were observed.

X: When the test was carried out three times at the same place, 50 to 100 square peelings were observed. 3. Appearance (1) Transparency The haze value is measured using a haze meter. (2) Cracks Observed visually, and the following criteria were used.

Δ: no cracks generated; Δ: slight cracks generated; ×: countless cracks generated. Hot water test After immersion in hot water of 80 ° C. for 2 hours and then taking out from the hot water, and left at room temperature for 1 hour, the adhesion was evaluated in accordance with paragraph 2. 5. Weather resistance test Q. U. Using V (a UV tester manufactured by Q Panel), an accelerated exposure test was performed for 1000 hours, with one cycle of ultraviolet irradiation 4 hours (atmospheric temperature 65 ° C.)-Condensation 4 hours (atmospheric temperature 45 ° C.). The crank of the coating was visually observed with respect to the sample after the exposure, and the adhesion was evaluated in accordance with Section 2.

Preparation of Acrylic Copolymers (1) to (5) 150 g of toluene and 50 g of n-butyl acetate were charged into a reaction vessel equipped with a stirrer and a condenser while replacing the atmosphere with nitrogen.
After the temperature was raised, 300 g of the monomer mixture shown in Table 1, 6 g of azobisisobutyronitrile and 1.5 g of n-dodecylmercaptan were added dropwise over about 2 hours to cause a stirring reaction. Further, 1.5 g of azobisisobutyronitrile was added, and 90 ° C.
And the reaction was stirred for 5 hours. Immediately before the completion of the reaction, 100 g of methyl ethyl ketone was added to terminate the reaction. The obtained copolymer had a nonvolatile content of 50% and a weight average molecular weight of 1.2.
10,000 to 30,000.

[0051]

[Table 1] Example 1 In a 1 14-neck flask reaction vessel equipped with a stirrer and a condenser, γ-
124 g of methacryloyloxypropyltrimethoxysilane (trade name: A-174, manufactured by Nippon Unicar) was charged,
While stirring the mixture, 27 g of a 0.001N hydrochloric acid aqueous solution was added, and then 515 g of isopropanol-dispersed colloidal silica (SiO ₂ concentration: 30% by weight, trade name: IPA-ST, manufactured by Nissan Chemical Industries, Ltd.) was gradually added. 51.5 g (25.75 g of non-volatile content) of the system copolymer (1) was charged.

After the mixture was stirred at room temperature for 1 hour, the reaction system was put under reduced pressure and volatile components were distilled off at 45 to 50 ° C. About 30 minutes after the start of the distillation, the distillation was stopped when the viscosity of the reaction system began to increase. The weight of the volatiles distilled out of the reaction system was 300 g. Next, the temperature of the reaction system was raised, and the reaction was carried out with stirring at 80 ° C. for 2 hours while refluxing the remaining volatiles. The obtained reaction product was a pale and colored viscous transparent liquid.

The reaction product was left to stand for one day and at room temperature, aged, weighed in an amount of 100 g, and added 0.5 g of a photopolymerization initiator methylphenylglyoxylate and 0.5 g of benzophenone.
g, 160 g of organic solvent isobutanol, 40 g of n-butyl acetate, and 40 g of ethyl cellosolve, and the mixture was stirred to prepare a transparent coating composition.

Using this coating composition, a methacrylic resin injection molded plate 3 mm thick, 100 × 100 mm (trade name: Acrypet-VH001 Tone Clear, Mitsubishi Rayon Co., Ltd.)
Was spray-coated to form a film, and then allowed to stand in a room temperature atmosphere for 20 minutes to evaporate the solvent. Then, this was put in an air atmosphere using a high-pressure mercury lamp (manufactured by IGRAPHIC Co., Ltd.) at 1500 mg / cm ² (wavelength 320 to 38).
Ultraviolet rays (integrated energy of ultraviolet rays of 0 nm) were irradiated to obtain a wear-resistant methacrylic resin plate having a cured film thickness of 8 μm. Example 2 A wear-resistant methacrylic resin plate was obtained according to Example 1 except that the acrylic copolymer (5) was used. The cured film thickness at this time was 7 μm. Example 3 Into the reaction vessel used in Example 1, 124 g of vinyltrimethoxysilane (trade name: A-171, manufactured by Nippon Unicar) was charged, and while stirring, 45 g of a 0.001 N hydrochloric acid aqueous solution was added. Then, 515 g of isopropanol-dispersed colloidal silica was gradually added, and finally 51.5 g of an acrylic copolymer (1) was charged. The mixture was stirred at room temperature for 5 hours, and then left to stand for one day to mature.

Next, the reaction system containing the ripening solution was placed under reduced pressure, and volatile components were distilled off at about 40 ° C. About 30 minutes after the start of the distillation, the distillation was stopped when the viscosity of the reaction system began to increase. The weight of volatiles distilled from the reaction system is 3
It was 20 g. Next, the temperature of the reaction system was raised, and the mixture was stirred at 80 ° C. for 2 hours while refluxing the remaining volatiles to cause a reaction. The obtained reaction product was a pale and colorless viscous transparent liquid. Using this reaction product, a coating composition was prepared according to Example 1. The treatment was performed in the same manner as in Example 1 except that the setting conditions of Example 1 were changed to 80 mC / min for ² minutes at 80 ° C. to obtain an abrasion-resistant methacrylic resin plate having a cured film thickness of 7 μm. Reference Example 4 118 g of γ-glycidoxypropyltrimethoxysilane (trade name: A-187, manufactured by Nippon Unicar) was charged into the reaction vessel used in Example 1, and distilled water 2 was added thereto while stirring.
7 g, then 500 g of isopropanol-dispersed colloidal silica were gradually added, and finally 60 g of the acrylic copolymer (1) was added. At room temperature, this mixture is
After stirring for an hour, the temperature of the reaction system was raised, and the reaction was carried out for 5 hours while refluxing volatile components. The obtained reaction liquid was a viscous transparent liquid colored slightly pink. After the reaction solution was aged overnight, 2 g of diphenyliodonium hexafluoroarsenate was added as a photoinitiator to prepare a coating composition. This coating composition was applied to the substrate of Example 1 by dip coating, allowed to stand at room temperature for 30 minutes, and then irradiated with 1500 mj / cm ² of ultraviolet light in an air atmosphere to obtain a cured film having a thickness of 5 m.
A μm-wear-resistant methacrylic resin plate was obtained. Reference Example 5 80 g of γ-methacryloyloxypropyltrimethoxysilane and 60 g of γ-glycidoxypropyltrimethoxysilane were charged into the reaction vessel used in Example 1, and 31.1 g of a 0.001N hydrochloric acid aqueous solution was added thereto while stirring. And then isopropanol-dispersed colloidal silica 50
0 g gradually, and finally the acrylic copolymer I shown in Table 1
Was charged. The mixture was reacted according to Reference Example 4, and 1 g of benzoinpropyl ether photoinitiator and 1 g of diphenyliodonium hexafluoroarsenate were added to the obtained reaction product to prepare a coating composition. The coating composition was treated according to Reference Example 4 to obtain a cured film having a thickness of 5.5 μm.
m was obtained. Example 6 The charged composition of Example 1 was changed as follows.

Γ-methacryloyloxypropyltrimethoxysilane 124 g 0.001 N hydrochloric acid aqueous solution 27 g Iso-propanol dispersed colloidal silica 434 g Acrylic copolymer (1) 100 g The reaction was carried out according to Example 1 with the above charged composition and color. A transparent viscous liquid was obtained. Using this, the same coating composition as in Example 1 was prepared. A treatment was performed in the same manner as in Example 1 to obtain a wear-resistant methacrylic resin plate having a cured film thickness of 8 μm. Example 7 To 100 g of the reaction product of Example 1, 0.5 g of methylphenylglyoxylate and 0.5 g of benzophenone were added, 3.4 g of 2,4-dihydroxybenzophenone as an ultraviolet absorber, 160 g of isobutanol, and n-butyl acetate 40 g and 40 g of ethyl cellosolve were added and stirred to prepare a coating composition.

Next, using this coating composition, polycarbonate
Nate resin injection molded board 3mm thick, 100 × 100mm (product
Name Lexan LS-2 Tone Clear, General Elect
Rick) to form a film, then dry
It was set in a dryer at 80 ° C. for 10 minutes. Then this
Using a high-pressure mercury lamp in air atmosphere, 2500 mj / cm ^Two 
Irradiation of ultraviolet light, abrasion-resistant polycarbonate with a cured film thickness of 7 μm
A carbonate resin plate was obtained. Example 8 This mixture was prepared under the same composition as in Example 1 but kept at room temperature for 1 hour.
Stirred. Next, raise the temperature of the reaction system and reflux the volatile components.
After stirring for 3 hours while aging, the mixture is aged overnight and the reaction product
Was prepared. Benzoin iso-propyl was added to the reaction product.
And 1.2 g of benzophenone.
A dressing composition was prepared. Using this, the ultraviolet light of Example 4 was used.
Irradiation fee 2000mj / cm^Two Example 4 except for changing to
Abrasion-resistant methacrylic tree with a cured film thickness of 6 μm
A fat plate was obtained. Example 9 This mixture was prepared at room temperature for 20 hours using the same composition as in Example 1.
After stirring for a while, the mixture was left to mature at room temperature for one week. This ripe
Preparation and processing of the coating composition according to Example 8 using the composition
To a wear-resistant methacrylic resin plate with a cured film thickness of 6 μm.
Obtained. Comparative Examples 1 to 3 According to Example 1 except that the acrylic copolymer was changed.
A reaction solution was prepared. Acrylic copolymer used and obtained
The appearance of the reaction solution thus obtained is as follows.

Comparative Example 1 Acrylic Copolymer (2) Turbid Low Viscosity Liquid Comparative Example 2 〃 ３ (3) Turbid Relatively High Viscous Liquid Comparative Example 3 〃 ４ (4) Transparent Brown Wax State Using the obtained reactant, a coating composition was prepared in the same manner as in Example 1 and treated under the same conditions as in Example 1 to obtain a wear-resistant methacrylic resin plate. The film thickness of the processed product was 7 to 8 μm. Comparative Example 4 124 g of γ-methacryloyloxypropyltrimethoxysilane, 27 g of a 0.001 N aqueous hydrochloric acid solution and 515 g of isopropanol-dispersed colloidal silica were charged into the reaction vessel of Example 1, stirred at room temperature for 1 hour, and then volatiles were refluxed. While stirring for 4 hours. The obtained reaction product was a pale pink low-viscosity transparent liquid. Using this reaction product, a coating composition was prepared and treated according to Example 8, to obtain an abrasion-resistant methacrylic resin plate having a cured film thickness of 5 μm. Comparative Example 5 The reaction vessel of Example 1 was charged with 248 g of γ-methacryloyloxypropyltrimethoxysilane and 54 g of a 0.001 N aqueous hydrochloric acid solution, and further an acrylic copolymer (1)
Was added, and the mixture was stirred at room temperature for 20 hours and left overnight at room temperature. Next, 0.7 g of methylphenylglyoxylate and 0.7 g of benzophenone were added to 100 g of the reaction solution.
g and 50 g of isopropyl alcohol were added to prepare a coating composition. Using this coating composition, a treatment was carried out in accordance with Example 8 to obtain a 6 μm-thick abrasion-resistant methacrylic resin plate. Comparative Example 6 In a 11-neck flask reaction vessel equipped with a stirrer and a condenser, γ-
124 g of methacryloyloxypropyltrimethoxysilane (trade name: A-174, manufactured by Nippon Unicar) was charged,
While stirring, 27 g of a 0.001 N hydrochloric acid aqueous solution was added, and then 515 g of iso-propanol-dispersed colloidal silica (SiO ₂ concentration: 30% by weight, trade name: IPA-ST, manufactured by Nissan Chemical Co., Ltd.) was gradually added. And finally 1,6
-51.5 g of hexanediol diacrylate was charged.

After the mixture was stirred at room temperature for 1 hour, the reaction system was put under reduced pressure and volatile components were distilled off at 45 to 50 ° C. About 30 minutes after the start of the distillation, the distillation was stopped when the viscosity of the reaction system began to increase. The weight of the volatiles distilled out of the reaction system was 300 g. Next, the temperature of the reaction system was raised, and the reaction was carried out with stirring at 80 ° C. for 2 hours while refluxing the remaining volatiles. The obtained reaction product was a pale yellow viscous transparent liquid.

The reaction product was left to stand at room temperature for 24 hours, aged, weighed, and weighed at 100 g.
g, 160 g of organic solvent isobutanol, 40 g of n-butyl acetate, and 40 g of ethyl cellosolve, and the mixture was stirred to prepare a transparent coating composition.

Using this coating composition, a methacrylic resin injection molded plate 3 mm thick and 100 × 100 mm (trade name: Acrypet-VH001 Tone Clear, Mitsubishi Rayon Co., Ltd.)
Was spray-coated to form a film, and then allowed to stand in a room temperature atmosphere for 20 minutes to evaporate the solvent. Then, this was put in an air atmosphere using a high-pressure mercury lamp (manufactured by IGRAPHIC Co., Ltd.) at 1500 mg / cm ² (wavelength 320 to 38).
(Integrated energy of ultraviolet light of 0 nm) was applied to obtain an injection-molded plate of abrasion-resistant methacrylic resin having a cured film thickness of 8 μm.

Table 2 shows the results obtained in the above Examples and Comparative Examples.

[0063]

[Table 2]

[0064]

The abrasion-resistant synthetic resin molded article obtained by using the coating composition of the present invention is excellent not only in abrasion resistance and scratch resistance but also in adhesion to a substrate. It is particularly useful for automotive-related parts with high demands on durability and weather resistance, particularly for applications such as headlight lens covers, tail lamps and side lamps.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Kawaguchi 4-160 Sunadabashi, Higashi-ku, Nagoya City, Aichi Prefecture 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-64-4664 (JP, A) JP-A-64-69673 (JP, A) JP-A-3-47854 (JP, A) ) Table 57-500984 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 1/00-201/10

Claims (2)

(57) [Claims] (A) 5 to 80% by weight of colloidal silica composed of silica particles having a primary particle size of 1 to 200 nm ; (b) the following general formula (I): (Where X is CH ₂ ＝ CH—COO—, CH ₂ ＣC (CH
₃₎ -COO- or CH ₂ = CH- group, R ¹ is a single bond or
A divalent hydrocarbon group, R ² and R ³ are a monovalent hydrocarbon group, a
Represents an integer of 1 to 3, b represents an integer of 0 to 2, and a + b represents an integer of 1 to 3. 5) to 80% by weight of a hydrolysis or condensation reaction product of at least one of the monomers represented by the formula (c), (c) acrylic acid and / or methacrylic acid having 1 to 1 carbon atoms.
A structural unit derived from the alkyl ester of 8 to 10 to 90
A coating composition comprising 1 to 30% by weight of an acrylic copolymer having a hydroxyl value of 10 to 300 mg KOH / g and (d) 0.1 to 5% by weight of a UV-sensitive photoinitiator. Wherein applying the coating composition of claim 1 wherein the surface of the synthetic resin molded article, and forming a cross-linked cured film on the surface of the synthetic resin molded product by irradiating ultraviolet rays synthesis A method for modifying the surface of resin molded products.