JPH0911405A - Plastic moldings with protected surface and manufacture thereof - Google Patents

Abstract

PURPOSE: To obtain plastic moldings having high surface hardness and favorable durability by laminating a first and a second layers formed of a mixture of a (partial) hydrolyzate of alkoxysilane with acrylic resins and a third layer formed of an organopolysiloxane resin, each composition being shown by the respective formulas, on the surface of a plastic base material. CONSTITUTION: A first and a second layers and a third layer are successively laminated on the surface of a plastic base material, wherein the first and the second layers are formed by thermosetting with the heat of reaction a mixture of 1-40wt.% and 40-90wt.% of a (partial) hydrolyzate of an alkoxysilane, shown by formula I (wherein R<2> represents an organic group having a 1-4C alkyl group, R<3> represents a 1-4C alkyl group and n represents an integer of 0-2), with 99-60wt.% and 60-10wt.% of respective acrylic resins having 1/99-50/50 of molar ratios in repeating unit formulas II, III and 1/99-100/0 of molar ratios in repeating unit formulas IV, V, in repeating units shown by formulas II, III, IV, V (wherein X represents a hydrogen atoms, R<4> represents a 2-5C alkylene group and R<5> represents a 1-4C alkyl group), while the third layer is formed by thermosetting an organopolysiloxane resin of a substance of a (partial) hydrolyzate of alkoxysilane shown by formula VI.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-protected plastic molding and a method for producing the same. More specifically, the present invention relates to a plastic molded article having a surface hardness significantly improved by coating the surface of a plastic substrate with a cured film having a specific three-layer structure, and a method for producing the same.

[0002]

2. Description of the Related Art Plastic materials are used in various fields because of their advantages such as impact resistance, light weight, workability and transparency. In particular, transparent plastics such as acrylic resin, polycarbonate resin, and styrene resin are widely used as substitutes for glass. However, these resins have drawbacks such as poor scratch resistance, easy scratching of the surface, and easy attack by a solvent.

For the purpose of improving these drawbacks, many proposals have heretofore been made to improve the surface hardness by coating the surface of plastic with a silicone-based cured film. For example, a coating composition comprising a partial condensate of trihydroxysilane and colloidal silica (Japanese Patent Application Laid-Open No. 51-25)
No. 736, JP-A-55-94971), and these cured coatings impart excellent abrasion resistance to plastic substrates. However, these coating compositions tend to crack when thickly applied because of shrinkage associated with the formation of a crosslinked network structure when they are heat-cured, and therefore, usually about 6 μm.
It is used with a film thickness of m or less. However, since the coating film thickness is thin, the influence of the surface hardness of the plastic substrate becomes strong, and sufficient scratch hardness cannot be obtained. Further, a composition is disclosed in which a hydrolysis-condensation product of a tetraalkoxysilane, an alkyltrialkoxysilane and a dialkyldialkoxysilane can be applied to a certain thickness with a suitable composition ratio among the three (Japanese Patent Laid-Open No. 62-275170). Gazette). With such a composition, the scratch hardness of the substrate is slightly improved, but the abrasion resistance is not obtained, and the surface is easily scratched by rubbing with steel wool or the like. In addition, urethane-based paint film, photo-cured film of polyfunctional acrylate-based resin,
A method has been proposed in which an organopolysiloxane-based thermosetting film is sequentially laminated to improve both scratch hardness and abrasion resistance of plastics (Japanese Patent Laid-Open No. 58-89359). In such a method, the photocurable layer and the siloxane layer do not adhere to each other at all, and therefore it is necessary to further provide an adhesive layer therebetween. Moreover, since the photo-curing and the thermo-setting are combined, not only the operation is complicated, but also the use of the photo-curing film causes a problem in durability such as weather resistance. Further, as a method for improving the surface hardness of a plastic substrate, a primer composition containing an acrylic resin having an alkoxysilyl group on the substrate has been disclosed (JP-A-5-78615). However, such a method having a two-layer structure has insufficient adhesion between the base material and the primer layer and has a problem in durability.

[0004]

An object of the present invention is to have a high surface hardness which is excellent in abrasion resistance and scratch hardness, and
It is to provide a plastic molded product having good durability.

[0005]

The inventors of the present invention have conducted extensive studies to improve the drawbacks of such a plastic molded product, and as a result, by laminating a three-layer structure consisting of specific layers on the surface of the plastic substrate, the surface hardness is improved. That is, the inventors have found that a plastic molded product having excellent abrasion resistance and scratch hardness and having excellent adhesion durability can be obtained, and thus the present invention has been accomplished.

That is, the present invention provides the following formula (A) on the surface of the plastic substrate.

[0007]

Embedded image R ² _n —Si (OR ³ ) _4-n ... (A) [wherein R ² is an alkyl group having 1 to 4 carbon atoms, a vinyl group, or a methacryloxy group, an amino group, an epoxy group] Group, an organic group having at least one group selected from the group consisting of mercapto groups, R ³ is an alkyl group having 1 to 4 carbon atoms, and n is an integer of 0 to 2. ] A (partial) hydrolyzate of alkoxysilane, a partial condensate thereof, or a mixture thereof of 1 to 40% by weight (based on the weight of R ² _n SiO _{(4-n) / 2) represented} by the following formula (B1 ) And (B2)

[0008]

Embedded image

[Wherein, X is a hydrogen atom or a methyl group, R ⁴ is an alkylene group having 2 to 5 carbon atoms, and R ^{5 is}
Is an alkyl group having 1 to 4 carbon atoms. ] And the molar ratio (p / q) of the repeating units (B1) and (B2) is 1/99 to 50/50.
The first layer formed by reacting and heat-curing a mixture or a reaction product of the acrylic resin (I) of 99 to 60% by weight, a (partial) hydrolyzate of the alkoxysilane represented by the formula (A), and a partial condensation thereof. 40 to 90% by weight of a substance or a mixture thereof (weight basis by R ² _n SiO _{(4-n) / 2} conversion) and the following formulas (C1) and (C2)

[0010]

Embedded image

[Wherein, X is a hydrogen atom or a methyl group, R ⁴ is an alkylene group having 2 to 5 carbon atoms, and R ^{5 is}
Is an alkyl group having 1 to 4 carbon atoms. ] And the molar ratio (r / s) of the repeating units (C1) and (C2) is 1/99 to 100/0.
A second layer formed by reacting and thermosetting a mixture or reaction product of 60 to 10% by weight of acrylic resin (II), which is represented by the following formula (E):

[0012]

Embedded image R ⁹ _v —Si (OR ¹⁰ ) _4-v ... (E) [wherein R ⁹ is an alkyl group having 1 to 4 carbon atoms, a vinyl group, or a methacryloxy group, an amino group, a glycidoxy group] It is a C1-C3 alkyl group substituted by one or more groups selected from the group consisting of groups, R ¹⁰ is a C1-C4 alkyl group, and v is an integer of 0-2. ] A third layer obtained by thermosetting an organopolysiloxane resin composed of a (partial) hydrolyzate of alkoxysilane, a partial condensate thereof, or a mixture thereof represented by It is a plastic molded product having a characteristic surface protection.

The first layer of the present invention is formed by reacting a (partial) hydrolyzate of an alkoxysilane, a partial condensate thereof or a mixture thereof and a mixture or a reaction product of an acrylic resin having a specific functional group with each other by heat curing. This is a thin film layer containing a large amount of organic components (acrylic resin components).

The alkoxysilane used in the first layer of the present invention is a tetra-, tri- or dialkoxysilane represented by the following formula (A).

[0015]

Embedded image in _{^{R 2 n -Si (OR 3)}} 4-n ··· (A) the above formulas, R ² is an alkyl group having 1 to 4 carbon atoms, a vinyl group, or a methacryloxy group, an amino group, an epoxy group , An organic group having at least one group selected from the group consisting of mercapto groups, R ³ is an alkyl group having 1 to 4 carbon atoms, and n is an integer of 0 to 2.

Here, the organic group is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, which may be linear, branched, or a combination thereof. . The organic group may have as a substituent one or more groups selected from methacryloxy group, amino group, epoxy group and mercapto group. When n is 2, R ² may be the same or different and may be a combination of two or more kinds.

Examples of such alkoxysilanes include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, vinyltrimethoxysilane and vinyltriethoxysilane. , 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- (2-aminoethyl ) -3-Aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, dimethyldimethoxysilane,
Examples thereof include vinylmethyldimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane and 3-aminopropylmethyldiethoxysilane. Tetraalkoxysilane and methyltrialkoxysilane are preferable in terms of scratch hardness of the obtained cured film, and methyltrimethoxysilane and methyltriethoxysilane are preferable in terms of economy and durability of the cured film. These compounds can be used alone or in combination of two or more.

The (partial) hydrolyzate of alkoxysilane and its partial condensate include those obtained by partially or entirely hydrolyzing the alkoxysilane, condensates obtained by subjecting part or all of the hydrolyzate to a condensation reaction, and The condensate is condensed with a raw material alkoxysilane which is not hydrolyzed,
These are obtained by a so-called sol-gel reaction.

The (partial) hydrolyzate of alkoxysilane and its partial condensate are usually 0.5 to 10 times equivalent, preferably 1 to 5 times equivalent to 1 equivalent of alkoxy group, and further 1 to 5 times equivalent to said alkoxysilane. Preferably, 1.5 to 3 times equivalent water is added, and the alkoxysilane is partially or entirely hydrolyzed in the presence of an acid catalyst with or without a solvent, and the hydrolysis. Part or all of the product is condensed, and these are obtained by so-called sol-gel reaction. The sol-gel reaction liquid containing the (partial) hydrolyzate of alkoxysilane and its partial condensate thus obtained is usually aged and used. The aging period depends on the type and concentration of the alkoxysilane used, the amount of water, the type and amount of the catalyst, and the type and amount of the diluting solvent, and therefore cannot be specified unconditionally, but usually the aging period of several hours to several days is required. After being applied, it is used in a coating composition.

Examples of the acid catalyst used here include inorganic acids such as hydrochloric acid, phosphoric acid, sulfuric acid, nitric acid, nitrous acid, perchloric acid and sulfamic acid, formic acid, acetic acid, propionic acid, butyric acid, oxalic acid, succinic acid, Organic acids such as maleic acid, lactic acid and p-toluenesulfonic acid can be mentioned. From the catalytic effect, the stability of the composition, the residual property when formed into a cured film, etc., preferably hydrochloric acid,
Acetic acid, particularly preferably acetic acid, is mentioned. The inorganic acid is usually 0.0001 to 2 N, preferably 0.001.
A concentration of 1 to 1 N, usually 0.1 to 50% by weight, preferably 1 to 20% by weight based on the alkoxysilane is used for an organic acid.

The solvent as a diluent can be preferably used either before the hydrolysis reaction of the alkoxysilane or during the reaction, that is, during the aging.

Further, the above solvent is usually an alcohol solvent such as methanol, ethanol, isopropanol, n-butanol, sec-butanol, 4-methyl-2-pentanol, 2-ethoxyethanol or 2-butoxyethanol. Used. These solvents are 2
More than one species can be used in combination.

The above sol-gel reaction solution preferably has a pH of 3.0 to 6.0 from the viewpoint of stability.

The acrylic resin (I) used in the first layer of the present invention is a (meth) acrylate polymer having a hydroxyl group, which is mainly composed of repeating units represented by the following formulas (B1) and (B2). .

[0025]

Embedded image

In the formula, X is a hydrogen atom or a methyl group, R ⁴ is an alkylene group having 2 to 5 carbon atoms, and R ^{5 is}
Is an alkyl group having 1 to 4 carbon atoms, and p / q is a molar ratio of 1/99 to 50/50. Further, (meth) acrylate means methacrylate or acrylate.

The acrylic resin (I) is a copolymer of a hydroxyl group-containing (meth) acrylate and an alkyl methacrylate, and can contain other vinyl monomer components described later. Examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate and 2- Hydroxy-isopropyl methacrylate, 2
-Hydroxy-isopropyl acrylate, 4-hydroxybutyl methacrylate, 4-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, 2-
Hydroxybutyl acrylate, 2-hydroxy-2 methyl-propyl methacrylate, 2-hydroxy-2 methyl-propyl acrylate, 2-hydroxy-2 methyl-butyl methacrylate, 2-hydroxy-pentyl acrylate, 2-hydroxy-3-methyl-propyl Methacrylate, 3-hydroxy-2,2-dimethylpropyl methacrylate and the like can be mentioned. From the viewpoint of the obtained performance and economy, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl methacrylate and 2-hydroxypropyl acrylate are particularly preferable. These compounds may be used alone or in 2
They can be used in combination of two or more species. Examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate and the like. In terms of the obtained performance, methyl methacrylate and ethyl methacrylate are particularly preferable. It is considered that when the number of carbon atoms of the alkyl group of the alkyl methacrylate is 5 or more, the hydrophobicity increases, but the compatibility with the sol-gel solution decreases and microphase separation easily occurs, and as a result, whitening may occur, which is not preferable. These compounds may be used alone or in combination of two or more.

The acrylic resin (I) has the above formula (B
The molar ratio of the (meth) acrylate repeating unit having a hydroxyl group represented by 1) to the alkyl methacrylate repeating unit represented by the above formula (B2) is p and q, respectively.
Then, p / q is a molar ratio of 1/99 to 50/50,
It is preferably a polymer mainly composed of 5/95 to 40/60. If the hydroxyl group content is less than 1 mol%, sufficient durability may not be obtained, and if it is greater than 50 mol%, the adhesion to the substrate may decrease.

The acrylic resin is preferably used in an amount of not more than 30 mol% with respect to the above (meth) acrylate polymer for the purpose of improving adhesiveness, solubility, durability, etc. without impairing its original performance. Other vinyl monomers can be added as a copolymerization component in a proportion of 15 mol% or less.

Examples of the vinyl monomer include styrene, vinyl acetate, acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate and 2-ethylhexyl methacrylate.

The acrylic resin can be obtained by polymerizing the above-mentioned (meth) acrylate having a hydroxyl group and alkyl methacrylate by any known method, but it contains random copolymerizability and ionic impurities. The radical copolymerization method in an inert solvent is preferable because it does not exist.

Examples of the polymerization solvent include hydrocarbons such as benzene, toluene, xylene, cyclohexane and hexane, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, 1,2-dimethoxyethane,
Examples thereof include ethers such as 1,3-dioxane and tetrahydrofuran, esters such as ethyl acetate, butyl acetate and ethoxyethyl acetate, and alcohols such as methanol, ethanol, isopropanol and n-butanol. Two or more kinds of these solvents may be used in combination.

A known radical initiator may be appropriately used as the polymerization initiator, and the polymerization temperature and the polymerization time depend on the initiator to be used and cannot be generally specified, but usually 50.
To 100 ° C, preferably 60 to 80 ° C for 2 to 24 hours,
It is preferably 4 to 10 hours.

The molecular weight of the acrylic resin of the first layer of the present invention is at least 20,000 or more, preferably 50,000 or more in terms of weight average molecular weight in order to sufficiently exhibit the performance as the first layer.

The first layer in the present invention comprises a sol-gel reaction liquid containing the (partial) hydrolyzate of the alkoxysilane, a partial condensate thereof or a mixture thereof, and a solution in which the acrylic resin (I) is dissolved. It is formed by mixing and preferably standing at room temperature for several hours or more, and then using this as a coating composition. By leaving the coating composition at room temperature for several hours or longer, a transparent and crack-free uniform cured film can be obtained. The reason for this is that when left as such, the (partial) hydrolyzate, its partial condensate or a mixture thereof (sol-gel reaction product) partially reacts with the hydroxyl group of the side chain of the acrylic resin or hydrogen bond. It is presumed that micro-uniformization will be performed.

The above-mentioned (partial) hydrolyzate of alkoxysilane, its partial condensate or a mixture thereof (sol-gel reaction product) and the acrylic resin (I) are mixed in a ratio of 1 to 40% by weight, preferably the former. 5 to 35% by weight (however, R
² _n SiO calculated as _{(4-n) / 2)} the latter is 99 to 60% by weight, preferably 95 to 65 wt%. If the amount of the sol-gel reaction product is too large, the cured film may be easily cracked and the adhesion to the plastic substrate may be deteriorated. If it is too small, the durability of the cured film, especially the water resistance may be deteriorated.

As a solvent for dissolving the acrylic resin,
After mixing with a sol-gel reaction liquid containing such a sol-gel reaction liquid,
It is only necessary that both components of the acrylic resin and the sol-gel reaction liquid are dissolved and the stability of the sol-gel reaction product is not impaired. Specifically, ethanol, isopropanol, n
Alcohols such as butanol, sec-butanol, 2-ethoxyethanol, 4-methyl-2-pentanol, 2-butoxyethanol, diacetone alcohol,
Ketones such as acetone, methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, methyl n-amyl ketone, cyclohexanone, diisopropyl ether, tetrahydrofuran, 1,4-dioxane,
1,3-dioxolane, 1,2-dimethoxyethane,
Ethers such as 1,2 diethoxyethane, hydrocarbons such as benzene, toluene, xylene, cyclohexane, n-hexane, ethyl acetate, butyl acetate, 2
-Ethoxyethyl acetate, 2-butoxyethyl acetate, esters such as ethyl butyrate, acetonitrile, nitromethane and the like can be mentioned. Of these, ketone solvents are preferable, and methyl ethyl ketone and methyl isobutyl ketone are particularly preferable. Further, two or more kinds of these solvents can be used in combination.

The above-mentioned coating composition used for forming the first layer of the present invention has a solid content of what is composed of a cured product obtained by a sol-gel reaction and an acrylic resin (I) (hereinafter referred to as solid content). The content is usually 1 to 40% by weight, preferably 3 to 30% by weight, and the solvent as the remaining amount may be entirely derived from the sol-gel solution and the acrylic resin solution, or newly added. Is also good. The solvent is selected from the above acrylic resin solvents. Also, at least about 10% by weight or more, preferably about 2% of the total amount of solvent.
It is desirable that 0% by weight is selected from the above alcohol solvents.

The coating composition is usually used as a curing catalyst.
Alkali metal salts of aliphatic carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, lactic acid, tartaric acid and succinic acid, alkali metal salts such as sodium salt, potassium salt, benzyltrimethylammonium salt, tetramethylammonium salt, tetraethylammonium salt, etc. Quaternary ammonium salt of, preferably sodium acetate, potassium acetate, tetramethylammonium acetate, benzyltrimethylammonium acetate.

Since the amount of the curing catalyst varies depending on the curing temperature and the curing time, it cannot be generally stated, but usually 100 parts by weight of the alkoxysilane (however, the weight calculated as R ² _n SiO _{(4-n) / 2) is used.} It is preferably added in an amount of 0.1 to 15 parts by weight based on (calculated as a standard).

Further, the coating composition may contain a melamine resin for the purpose of improving durability such as water resistance and improving scratch hardness. Examples of such melamine resins include those in which a part or all of the methylol groups of hexamethylolmelamine are methyl etherified, or those in which a part or all of the methylol groups are butyl etherified, and the like, and their monomers. Alternatively, various oligomers are commercially available, and any of them can be preferably used. Examples thereof include Cymel resin manufactured by Mitsui Cytec Co., Ltd. and Uban resin manufactured by Mitsui Toatsu Chemicals, Inc. The melamine resin is 10 parts by weight based on 100 parts by weight of the acrylic resin (I).
It is used in an amount of 0 parts by weight or less, preferably 50 parts by weight or less.

An acid catalyst can be used for the purpose of curing the melamine resin at a relatively low temperature in a short time. Examples of the acid catalyst include benzenesulfonic acid, p-toluenesulfonic acid, methanesulfonic acid, phthalic acid, maleic acid, itaconic acid, succinic acid, citric acid, acetic acid, propionic acid, phosphoric acid, phosphorous acid, phenylphosphonic acid. ,nitric acid,
Examples thereof include hydrochloric acid, sulfuric acid, sulfamic acid, etc., and these acids are appropriately selected according to the purpose. The acid is usually added in an amount of 20 parts by weight or less, preferably 5 parts by weight or less, based on 100 parts by weight of the melamine resin.

Further, the above coating composition may contain a light stabilizer and an ultraviolet absorber in order to improve the weather resistance of the plastic substrate. Further, these agents can be used in combination.

Examples of the light stabilizer include bis (2,2,2
6,6-Tetramethyl-4-piperidyl) carbonate, bis (2,2,6,6-tetramethyl-4-piperidyl) succinate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate , 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 4-
Hexanoyloxy-2,2,6,6-tetramethylpiperidine, 4-octanoyloxy-2,2,6,6-
Tetramethylpiperidine, bis (2,2,6,6-tetramethyl-4-piperidyl) diphenylmethane-p,
p'-dicarbamate, bis (2,2,6,6-tetramethyl-4-piperidyl) benzene-1,3-disulfonate, bis (2,2,6,6-tetramethyl-4-piperidyl) phenyl Hindered amines such as phosphite, nickel bis (octylphenyl) sulfide,
[2,2′-thiobis (4-tert-octylphenolate)] N-butylamine nickel, [2,2′-thiobis (4-tert-octylphenolate)] triethanolamine nickel, nickel complex-3,5 Examples include nickel complexes such as di-tert-butyl-4-hydroxybenzyl phosphate monoethylate and nickel dibutyl dithiocarbamate. These agents may be used alone or in combination of two or more.
It is used in an amount of 50 parts by weight or less, preferably 20 parts by weight or less with respect to parts by weight.

Examples of the ultraviolet absorber include 2-hydroxy-4-methoxybenzophenone and 2-hydroxy-
Benzophenones such as 4-octoxybenzophenone, 2,4-dihydroxybenzophenone and 2,2′-dihydroxy-4-methoxybenzophenone, 2- (5′-
Methyl-2'-hydroxyphenyl) benzotriazole, 2- [2'-hydroxy-3 ', 5'-bis (α,
α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (3 ′, 5′-di-tert-butyl-
2′-hydroxyphenyl) benzotriazole, 2-
(3'-tert-butyl-5'-methyl-2'-hydroxyphenyl) -5-chlorobenzotriazole, 2
-(2'-hydroxy-5'-tert-octylphenyl) benzotriazole, 2- (3 ', 5'-di-t
ert-Butyl-2'-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3 ', 5'-di-te
benzotriazoles such as rt-amyl-2′-hydroxyphenyl) benzotriazole, cyanoacrylates such as ethyl-2-cyano-3,3-diphenylacrylate, 2-ethylhexyl-2-cyano-3,3-diphenylacrylate , Phenyl salicylate, p-
Salicylates such as tert-butylphenyl salicylate and p-octylphenyl salicylate, diethyl p
And benzylidene malonates such as methoxybenzylidene malonate and bis (2-ethylhexyl) benzylidene malonate. These agents may be used alone or in combination of two or more.
It is used in an amount of 100 parts by weight or less, preferably 50 parts by weight or less, based on parts by weight.

The coating composition for the first layer in the present invention is applied onto a plastic substrate by a commonly used method such as dip coating, spray coating, flow coating, roll coating, bar coating and spin coating. The shape of the base material can be appropriately selected. The base material coated with such a composition is usually subjected to dry removal of the solvent from room temperature to a temperature not higher than the heat distortion temperature of the base material, and then at a temperature of about 40 to about 140 ° C for about 10 minutes to about 4 hours. By heat-curing, the composite film of the organopolysiloxane and the acrylic resin, which is the first layer of the present invention, is formed.

A part or all of the heat curing can also serve as the heat curing of the second layer and the third layer, which will be described later, which are laminated on the first layer.

The film thickness of the first layer is required to sufficiently adhere the plastic substrate to the second and subsequent layers in the present invention, and to maintain the necessary amount of the above-mentioned weather resistance improver. It is sufficient that it is usually 0.1 to 10 μm, preferably 1 to 5 μm.
m.

When the composite film composed of the organopolysiloxane and the acrylic resin (I) forms the first layer, the adhesion between the second layer, which will be described later, and the plastic base material becomes good, and the durability is excellent. It is possible to obtain a molded plastic product.

The second layer in the present invention is obtained by thermosetting a mixture or reaction product of a (partial) hydrolyzate of an alkoxysilane, a partial condensate thereof or a mixture thereof and an acrylic resin having a specific functional group. Is a thin film layer.

As the (partial) hydrolyzate of alkoxysilane, its partial condensate or a mixture thereof used in the second layer in the present invention, the same ones as those used to form the above-mentioned first layer should be used. You can

The hydroxyl group-containing acrylic resin (II) used in the second layer of the present invention is a (meth) acrylate polymer mainly composed of repeating units represented by the following formulas (C1) and (C2).

[0053]

Embedded image

In the formula, X is a hydrogen atom or a methyl group, R ⁴ is an alkylene group having 2 to 5 carbon atoms, and R ^{5 is}
Is an alkyl group having 1 to 4 carbon atoms. When the molar amounts of the repeating units represented by the above formulas (C1) and (C2) are r and s, respectively, r / s is 1/99 to 100 / in a molar ratio.
0. Further, (meth) acrylate means methacrylate or acrylate.

The acrylic resin (II) is a homopolymer of a hydroxyl group-containing (meth) acrylate or a copolymer of the hydroxyl group-containing (meth) acrylate and an alkyl methacrylate. A monomer component can be included. Examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl methacrylate and 2
-Hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate, 2-hydroxy-isopropyl methacrylate, 2-hydroxy-isopropyl acrylate, 4-
Hydroxybutyl methacrylate, 4-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxy-2 methyl-propyl methacrylate, 2-hydroxy-2 methyl-propyl acrylate, 2-hydroxy-2 methyl-butyl Methacrylate, 2-hydroxy-
Pentyl acrylate, 2-hydroxy-3-methyl-
Examples include propyl methacrylate and 3-hydroxy-2,2-dimethylpropyl methacrylate. In terms of the obtained performance and economy, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 2
-Hydroxypropyl methacrylate and 2-hydroxypropyl acrylate are preferred. These compounds may be used alone or in combination of two or more. Further, as the alkyl methacrylate, methyl methacrylate,
Ethyl methacrylate, n-propyl methacrylate,
Examples thereof include isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate and tert-butyl methacrylate. In terms of the obtained performance, methyl methacrylate and ethyl methacrylate are particularly preferable. It is considered that when the number of carbon atoms of the alkyl group of the alkyl methacrylate is 5 or more, the hydrophobicity increases, but the compatibility with the sol-gel solution decreases and microphase separation easily occurs, resulting in whitening, which is not preferable. . These compounds may be used alone or in combination of two or more.

In the acrylic resin (II), the molar ratio (r / s) of the (meth) acrylate repeating unit having a hydroxyl group and the alkyl methacrylate repeating unit is 1 /
It is a polymer mainly composed of 99 to 100/0, preferably 5/95 to 100/0. If the hydroxyl group content is less than 1 mol%, sufficient scratch hardness cannot be obtained.

The acrylic resin is preferably used in an amount of 30 mol% or less with respect to the above (meth) acrylate polymer for the purpose of improving the adhesiveness, solubility, durability and the like without impairing its original performance. Other vinyl monomers can be added as a copolymerization component in a proportion of 15 mol% or less.

Examples of the vinyl monomer include styrene, vinyl acetate, acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate and 2-ethylhexyl methacrylate.

The acrylic resin (II) can be obtained by polymerizing the above-mentioned (meth) acrylate having a hydroxyl group and alkylmethacrylate by any known method. The radical copolymerization method in an inert solvent is preferable because it does not contain impurities.

As the polymerization solvent, hydrocarbons such as benzene, toluene, xylene, cyclohexane and hexane, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, 1,2-dimethoxyethane,
Examples thereof include ethers such as 1,3-dioxane and tetrahydrofuran, esters such as ethyl acetate, butyl acetate and ethoxyethyl acetate, and alcohols such as methanol, ethanol, isopropanol and n-butanol. Two or more kinds of these solvents may be used in combination.

As the polymerization initiator, a known radical initiator may be appropriately used, and the polymerization temperature and the polymerization time depend on the initiator to be used and cannot be generally specified, but usually 50.
To 100 ° C, preferably 60 to 80 ° C for 2 to 24 hours,
It is preferably 4 to 10 hours.

The acrylic resin (II) has a weight average molecular weight of 20,000 to 600,000, preferably 40,000 to 400,000. When the molecular weight is lower than 20,000, the coating property and the flexibility of the obtained film are low and cracks are easily generated, and when the molecular weight is higher than 600,000, the stability of the coating composition described later is lowered.

The second layer in the present invention comprises a sol-gel reaction liquid containing the (partial) hydrolyzate of the alkoxysilane, its partial condensate or a mixture thereof, and a solution in which the acrylic resin (II) is dissolved. It is formed by mixing and preferably standing at room temperature for several hours or more, and then using this as a coating composition. By leaving the coating composition at room temperature for several hours or longer, a transparent and crack-free uniform cured film can be obtained. The reason for this is presumed that during the standing period, the sol-gel reaction product partially reacts with the hydroxyl group of the side chain of the acrylic resin or is hydrogen-bonded to be micro-homogenized.

The above-mentioned (partial) hydrolyzate of alkoxysilane, its partial condensate or a mixture thereof and the acrylic resin (II) are mixed in a proportion of 40 to 90% by weight, preferably 50 to 80% by weight. (However, calculated on the basis of weight by R ² _n SiO _{(4-n) / 2} conversion), the latter is 60 to 10% by weight, preferably 50 to 20% by weight. If the amount of the sol-gel reaction product is too large, cracks are likely to occur in the cured film, and if it is too small, the durability, particularly water resistance, of the cured film decreases, and the scratch hardness of the cured film becomes insufficient.

The solvent for the acrylic resin may be any solvent as long as it dissolves both components after mixing with the sol-gel reaction solution and does not impair the stability of the sol-gel reaction product. Specifically, ethanol, isopropanol, n-butanol, sec-butanol, 2-ethoxyethanol, 4-methyl-2-
Alcohols such as pentanol, 2-butoxyethanol, diacetone alcohol, acetone, methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, methyl n-amyl ketone, cyclohexanone and other ketones, diisopropyl ether, tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane, 1,
Ethers such as 2-dimethoxyethane and 1,2-diethoxyethane, hydrocarbons such as benzene, toluene, xylene, cyclohexane and n-hexane, ethyl acetate, butyl acetate, 2-ethoxyethyl acetate and 2-butoxyethyl acetate. , Esters such as ethyl butyrate, acetonitrile, nitromethane and the like. Of these, ketone solvents are preferable, and methyl ethyl ketone and methyl isobutyl ketone are particularly preferable.
Further, two or more kinds of these solvents can be used in combination.

The above solution consisting of the acrylic resin and the solvent is added with water and an acid catalyst to the solution before mixing with the sol-gel reaction solution, and as described above, the side chain alkoxysilyl group of the acrylic resin is added. , Can be previously (partially) hydrolyzed.

The coating composition used for forming the second layer of the present invention comprises a cured product obtained by a sol-gel reaction and an acrylic resin (II) having the above specific functional group (hereinafter referred to as solid content). Content) is usually 3 to 50% by weight, preferably 5 to 35% by weight, and the residual solvent is
The total amount may be derived from the sol-gel solution and the acrylic resin solution, or may be newly added. The solvent is selected from the above acrylic resin solvents. Also,
At least about 10% by weight or more, preferably about 20% by weight of the total amount of the solvent is selected from the above alcohol solvents.

The coating composition is usually used as a curing catalyst.
Alkali metal salts of aliphatic carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, lactic acid, tartaric acid and succinic acid, alkali metal salts such as sodium salt, potassium salt, benzyltrimethylammonium salt, tetramethylammonium salt, tetraethylammonium salt, etc. Quaternary ammonium salt of, preferably sodium acetate, potassium acetate, tetramethylammonium acetate, benzyltrimethylammonium acetate.

Although the amount of the curing catalyst varies depending on the curing temperature and the curing time, it cannot be generally stated, but usually 100 parts by weight of the alkoxysilane (however, calculated as R ² _n SiO _{(4-n) / 2} ). It is preferable to add it in 0.1 to 15 parts by weight.

The coating composition may also contain a melamine resin for the purpose of improving durability such as water resistance and scratch resistance. Examples of the melamine resin include those in which some or all of the methylol groups of hexamethylolmelamine are methyl etherified, or those in which some or all of the methylol groups are butyl ether, and the like, and their monomers. Alternatively, various oligomers are commercially available, and any of them can be preferably used. Examples thereof include Cymel resin manufactured by Mitsui Cytec Co., Ltd. and Uban resin manufactured by Mitsui Toatsu Chemicals, Inc. The melamine resin is usually 100 parts by weight based on 100 parts by weight of the acrylic resin.
It is used in an amount of not more than 50 parts by weight, preferably not more than 50 parts by weight.
Excessive addition of the melamine can cause the composition to gel.

An acid catalyst can be used for the purpose of curing the melamine resin at a relatively low temperature in a short time. Examples of the acid catalyst include benzenesulfonic acid, p-toluenesulfonic acid, methanesulfonic acid, phthalic acid, maleic acid, itaconic acid, succinic acid, citric acid, acetic acid, propionic acid, phosphoric acid, phosphorous acid, phenylphosphonic acid. ,nitric acid,
Examples thereof include hydrochloric acid, sulfuric acid, sulfamic acid, etc., and these acids are appropriately selected according to the purpose. The acid is usually added in an amount of 20 parts by weight or less, preferably 5 parts by weight or less, based on 100 parts of the melamine resin.

Further, in the composition for the second layer, for the purpose of further improving the weather resistance of the plastic substrate, the additives such as the light stabilizer and the ultraviolet absorber as described above are coated in the second layer. It can be contained in an amount that does not impair the performance. Usually, two or more of these agents can be used in combination, and the total amount of the additives can be 20 parts by weight or less, preferably 10 parts by weight or less, based on 100 parts by weight of the solid content of the composition.

The coating composition for the second layer in the present invention is applied on the first layer formed on the plastic substrate. As the coating method, commonly used methods such as dip coating, spray coating, flow coating, roller coating, bar coating and spin coating are used.
It can be appropriately selected depending on the shape of the molded body. The applied molded body is usually subjected to solvent removal by drying at a temperature from room temperature to a temperature not higher than the heat distortion temperature of the substrate, and then 40 to 1
By heat-curing at a temperature of 40 ° C. for 10 minutes to 4 hours, a composite film of the organopolysiloxane and the acrylic resin, which is the second layer of the present invention, is formed.

Part or all of the heat curing can also serve as the heat curing of the third layer laminated on the second layer.

The film thickness of the second layer varies depending on the required scratch hardness, but is usually 3 to 100 μm, preferably 5 to 100 μm.
The thickness is 80 μm, more preferably 8 to 50 μm. If the film thickness is less than 3 μm, the effect of improving scratch hardness cannot be obtained, and if it is more than 100 μm, cracks are likely to occur.

The third layer contains a (partial) hydrolyzate of an alkoxysilane represented by the following formula (E), a partial condensate thereof or a mixture thereof as a substantial solid content, and contains a solvent, an acid and a small amount of curing. It is formed using a coating composition comprising a catalyst.

[0077]

Embedded image wherein _{^{R 9 v -Si (OR 10)}} 4-v ··· (E), wherein R ⁹ is an alkyl group having 1 to 4 carbon atoms, a vinyl group, or methacryloxy group, amino group, glycidoxy It is a C1-C3 alkyl group substituted by one or more groups selected from the group consisting of groups, R ¹⁰ is a C1-C4 alkyl group, and v is an integer of 0-2. As the above-mentioned alkoxysilane, any of tetra-, tri-, and dialkoxysilane can be used. Examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, and tetra-n-butoxysilane. Above all, tetramethoxysilane and tetraethoxysilane are preferable in terms of economy and reactivity. Examples of the trialkoxysilane include methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, methyltrin-butoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane, propyltrimethoxysilane, and the like. Butyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-
Methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, methacryloxymethyltrimethoxysilane, methacryloxymethyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycid Examples include xypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane. Of these, methyltrialkoxysilane is preferable in terms of wear resistance and crack resistance of the cured film to be obtained, and methyltrimethoxysilane and methyltriethoxysilane are preferable in terms of economy and reactivity. Examples of dialkoxysilanes include dimethyldimethoxysilane, vinylmethyldimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-aminopropylmethyldiethoxysilane. These compounds can be used alone or in combination of two or more.

From the viewpoint of the performance of the resulting coating film, the alkoxysilane is 40 mol% or less of tetraalkoxysilane and 6
It is preferably composed mainly of 0 mol% or more trialkoxysilane. By using tetraalkoxysilane, the abrasion resistance of the resulting coating film is improved, but when tetraalkoxysilane is used in an amount of more than 40 mol%, the coating film becomes relatively brittle and cracks easily occur.

The (partial) hydrolyzate of alkoxysilane and its partial condensate are synonymous with those obtained by so-called sol-gel reaction in the above-mentioned first and second layers.

The third layer preferably contains colloidal silica. That is, a trialkoxysilane represented by the following formula (D) as the substantial solid content (the above formula (E))
(Corresponding to v = 1 in 1), a partial hydrolyzate thereof, a partial condensate thereof or a mixture thereof and colloidal silica, and a coating composition comprising a solvent, an acid and a small amount of a curing catalyst.

[0081]

Embedded image wherein _{^{R 7 -Si (OR 8) 3}} ··· (D), wherein R ⁷ is an alkyl group having 1 to 4 carbon atoms, a vinyl group, or methacryloxy group, amino group, glycidoxy group It is an alkyl group having 1 to 3 carbon atoms substituted with one or more groups selected from the group, and R ⁸ is an alkyl group having 1 to 4 carbon atoms.

Examples of the trialkoxysilane represented by the above formula (D) include methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, methyltrin-butoxysilane, ethyltrimethoxysilane and ethyltriethoxysilane. , Ethyltriisopropoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, methacryloxymethyltrimethoxy Silane, Methacryloxymethyltriethoxysilane, 3-
Aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane and the like can be mentioned.

Further, in terms of wear resistance of the obtained cured film,
At least 70% by weight of the trialkoxysilane is preferably methyltrialkoxysilane, more preferably the total amount of the trialkoxysilane is methyltrialkoxysilane, and more preferably methyltrimethoxysilane and methyltriethoxysilane. . These compounds can be used alone or in combination of two or more. It is also preferable to add a small amount of the above trialkoxysilane other than methyltrialkoxysilane for the purpose of imparting another function.

Colloidal silica has a particle size of 5
It is -100 nm, preferably 10-30 nm, and usually an aqueous dispersion or a lower aliphatic alcohol dispersion containing 10 to 50% by weight of colloidal silica is used, and an aqueous dispersion is preferably used. Such colloidal silica is commercially available under the trade name of, for example, Snowtex manufactured by Nissan Chemical Industries, Cataloid manufactured by Catalysts & Chemicals Industry, Oscar, Ludox manufactured by DuPont of the United States, and Nalcoag manufactured by Nalco Chemical of the United States. .

The mixing ratio of the (partial) hydrolyzate of trialkoxysilane, its partial condensate or a mixture thereof with colloidal silica depends on the stability of the coating composition used, the transparency of the cured film obtained, and the abrasion resistance. 90% to 30% by weight of a (partial) hydrolyzate of the trialkoxysilane, a partial condensate thereof, or a mixture thereof in the finally formed third layer.
(However, it is calculated on the basis of the weight of R ⁷ SiO _3/2 ), and the colloidal silica is made to be 10 to 70% by weight. Further, such (partial) hydrolyzate, its partial condensate or a mixture thereof, and colloidal silica are contained in the coating composition in an amount of 10 to 5 as a substantial solid content.
It is contained in an amount of 0% by weight, preferably 15 to 30% by weight.

The (partial) hydrolyzate of the alkoxysilane represented by the above formula (E) (and (D)) and its partial condensate are usually 1 to 10 times the equivalent amount of the alkoxy group of the alkoxysilane. Equivalent, preferably 1.5-7 times equivalent,
More preferably, it can be obtained by adding 2 to 4 times equivalent amount of water, and reacting in the presence of an acid catalyst without solvent or under dilution with a solvent. In the case of the trialkoxysilane of the above formula (D), the colloidal silica aqueous dispersion used usually contains a sufficient amount of water necessary for the hydrolysis reaction and partial condensation reaction of the trialkoxysilane. You may add more water. The thus obtained alkoxysilane (partial) hydrolyzate, its partial condensate or a mixture thereof is condensed with Si-O when a Si-OH is produced by hydrolysis in a water / alcohol-based acidic medium. -Si bond formation. However, the condensation is partial rather than complete and the condensate retains a significant amount of Si-OH groups and is thereby dissolved in the water / alcohol solvent.

The sol-gel reaction liquid containing the (partial) hydrolyzate of the alkoxysilane, its partial condensate, or a mixture thereof is usually aged and used. The aging period at this time depends on the type and concentration of the alkoxysilane used, the amount of water, the type and amount of the catalyst, and the type and amount of the diluting solvent, so it cannot be said unequivocally, but it is usually a few hours to several days. It is then used as a composition for coating.

As the solvent used in the coating composition,
It is necessary that the above-mentioned (partial) hydrolyzate of alkoxysilane, its partial condensate or a mixture thereof is stably dissolved, and for that purpose, at least 20% by weight or more,
It is desirable that 50% by weight or more is alcohol. Examples of such alcohol include methanol, ethanol, isopropanol, n-butanol,
sec-butanol, 2-ethoxyethanol, 4-methyl-2-pentanol, 2-butoxyethanol and the like can be mentioned, and a low-boiling alcohol having 1 to 4 carbon atoms is preferable, and solubility, stability and coating property are preferable. In particular, isopropanol is preferred. In the solvent, a lower aliphatic alcohol accompanying the hydrolysis of the trialkoxysilane, an excess amount of water as a dispersion medium of colloidal silica, which does not participate in the hydrolysis reaction, or a dispersion medium of colloidal silica Also included are lower aliphatic alcohols. Other solvents are required to be mixed with water / alcohol, for example, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, 1,
Examples thereof include ethers such as 4-dioxane and 1,2-dimethoxyethane, and esters such as ethyl acetate and ethoxyethyl acetate.

The solvent used in the coating composition is
It is necessary that the above-mentioned (partial) hydrolyzate of alkoxysilane, its partial condensate or a mixture thereof is stably dissolved, and for that purpose, at least 20% by weight or more,
It is desirable that 50% by weight or more is alcohol. Examples of such alcohol include methanol, ethanol, isopropanol, n-butanol,
sec-butanol, 2-ethoxyethanol, 4-methyl-2-pentanol, 2-butoxyethanol and the like can be mentioned, and a low-boiling alcohol having 1 to 4 carbon atoms is preferable, and solubility, stability and coating property are preferable. In particular, isopropanol is preferred. The solvent also contains a lower aliphatic alcohol that accompanies hydrolysis of the alkoxysilane. As the other solvent, it is necessary to be miscible with water / alcohol, for example, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, ethers such as tetrahydrofuran, 1,4-dioxane and 1,2-dimethoxyethane, Examples thereof include esters such as ethyl acetate and ethoxyethyl acetate.

The coating composition has a pH of 3.0 to 6.0, preferably 4.0 to 6.0, by containing an appropriate acid.
It is necessary to adjust it to 5.5. As a result, the hydrolysis reaction and partial condensation reaction of the alkoxysilane can be promoted, gelation at room temperature can be prevented, and storage stability can be increased. Such an acid may be added to the alkoxysilane in advance, or may be added after hydrolysis of the alkoxysilane. Further, the addition can be performed once or divided into two or more times. Examples of the acid used include hydrochloric acid, phosphoric acid, sulfuric acid, nitric acid, nitrous acid, perchloric acid, inorganic acids such as sulfamic acid, formic acid, acetic acid, propionic acid, butyric acid, oxalic acid, succinic acid, maleic acid, and lactic acid. Examples thereof include organic acids such as p-toluenesulfonic acid, and hydrochloric acid or acetic acid is particularly preferable. The acid varies depending on its acidity and the like, but is usually added in an amount of 2% by weight or less based on the composition.

Further, the coating composition contains a catalyst for promoting heat curing. As such a catalyst, the same one as the above-mentioned second layer curing catalyst can be used. Particularly, sodium acetate, potassium acetate, benzyltrimethylammonium acetate, and tetramethylammonium acetate are preferable. The addition amount varies depending on the curing conditions, but 0.01 to 5% by weight, preferably 0.05
~ 2% by weight. If the addition amount is less than 0.01% by weight, a sufficient curing rate cannot be obtained, and if the addition amount is more than 5% by weight, the storage stability is lowered or a precipitate is generated.

The coating composition for the third layer in the present invention is applied onto the second layer and heated to form a third layer.
A layer is formed. To apply such a coating composition, a commonly used method such as dip coating, spray coating, flow coating, roll coating, bar coating, spin coating is used, and it may be appropriately selected depending on the shape of the molded product. You can The applied molded body is usually subjected to solvent evaporation removal at a temperature from room temperature to a temperature not higher than the heat distortion temperature of the substrate. Then, it is heat-cured at a temperature of 50 to 150 ° C. for 10 minutes to 4 hours, and the residual silanol is condensed in this process, and the abrasion-resistant and solvent-resistant thin film of the third layer of the present invention is formed on the plastic molded article. It is firmly adhered via the first layer and the second layer.

As described above, part or all of the heat curing operation can also serve as the heat curing of the second layer.

The thickness of the third layer is usually 1 to 10 μm, preferably 2 to 8 μm, more preferably 3 to 7 μm. If the film thickness is smaller than 1 μm, sufficient abrasion resistance cannot be obtained, and if it is larger than 10 μm, cracks are likely to occur.

For the purpose of improving the coatability of the above-mentioned composition for the first layer, the second layer and the third layer of the present invention and the smoothness of the resulting coating film, a known leveling agent is added to the composition. Can be used. The amount added is usually in the range of 0.01 to 2% by weight based on the composition.

The plastic substrate used in the present invention may be transparent or opaque, and examples of such a substrate include polycarbonate resins such as poly (bisphenol-A carbonate), acrylic resins such as polymethylmethacrylate, polyethylene terephthalate and polybutylene. Polyester resins such as terephthalate and poly (ethylene-2,6-naphthalate), nylon-6, nylon-6,6
And other vinyl resins such as polystyrene, polyacrylonitrile, acrylonitrile-styrene copolymer, polyvinyl chloride, poly-4-methylpentene, and polypropylene. Due to the usefulness of the obtained coating effect and the adhesiveness to the substrate, polybisphenol-
A polycarbonate resin such as A carbonate and an acrylic resin such as polymethylmethacrylate are preferable, and poly (bisphenol-A carbonate) is particularly preferable.

[0097]

The surface-protected plastic molded article of the present invention thus obtained has a layer obtained by reacting a sol-gel reaction product with an acrylic resin having a hydroxyl group and heat-curing the first layer and the second layer. Consists of a three-layer structure
Further, the content of the sol-gel reaction product in each layer increases in the order of the first layer, the second layer, and the third layer, so that a molded article having high wear resistance, scratch hardness, and solvent resistance with durability. Is.

Such molded articles are, for example, windows of aircraft, vehicles, automobiles, headlight lenses, windows of construction machinery, optical lenses, mirrors, glasses, goggles, sound insulation walls, traffic light lenses, etc. Curve mirror, building, house, garage,
It can be preferably used for greenhouses, windows such as arcades, roofs, windshields, name plates, and other various sheets and films.

[0099]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, parts and% mean weight basis.

Reference Examples 1 to 6 (Synthesis Examples of Acrylic Resins A to F) (Synthesis Examples of Acrylic Resins A to F) a) A flask equipped with a reflux condenser and a stirrer and replaced with nitrogen was charged with 2-hydroxyethyl. Methacrylate (hereinafter abbreviated as HEMA) 13.1 parts, MMA 90.1 parts, azobisisobutyronitrile (hereinafter abbreviated as AIBN) 0.1
Add 6 parts and 200 parts of 1,2-dimethoxyethane,
Dissolved. Then, the mixture was reacted in a nitrogen stream at 70 ° C. for 6 hours with stirring. The obtained reaction system was purified by reprecipitation in a mixed solvent of n / 1-hexane and isopropyl alcohol in a weight ratio of 3/1, and HEMA / MMA composition ratio 10/90 (molar ratio).
95 parts of copolymer (acrylic resin-A) was obtained. The weight average molecular weight of the polymer was 100,0 by GPC measurement.
00.

Similarly, HEMA / MMA / composition ratio 3
Copolymer of 0/70 (molar ratio) (acrylic resin-
B), a 67/33 (molar ratio) copolymer (acrylic resin-C) was synthesized. Weight average molecular weight is 20 each
It was 50,000 and 60,000.

B) 39.0 parts of HEMA, 80.1 parts of ethyl methacrylate (hereinafter abbreviated as EMA), AIBN0.
108 parts of copolymer (acrylic resin-D) having a HEMA / EMA composition ratio of 30/70 (molar ratio) was obtained in the same manner as in the above e) except that 16 parts and 240 parts of 1,2-dimethoxyethane were used. The weight average molecular weight of the polymer is 1
It was 80,000.

C) 2-hydroxypropyl methacrylate (hereinafter abbreviated as HPMA) 43.2 parts, MMA 70.1
HP, in the same manner as in b) above, except that 0.16 parts of AIBN and 220 parts of 1,2-dimethoxyethane were used.
108 parts of a copolymer (acrylic resin-E) having a MA / MMA composition ratio of 30/70 (molar ratio) was obtained. The weight average molecular weight of the polymer was 150,000. d) 2-hydroxyethyl acrylate (hereinafter abbreviated as HEA) 23.2 parts, MMA80.1 parts, AIBN0.1
HEA / MMA composition ratio 2 in the same manner as in the above a) except that 6 parts and 200 parts of 1,2-dimethoxyethane were used.
95 parts of a 0/80 (molar ratio) copolymer (acrylic resin-F) was obtained. The weight average molecular weight of the polymer is 150,
000.

The following test methods were used to evaluate the performance of the cured coating film.

(1) Adhesiveness: Vertically on the surface of the test piece with a knife,
Make 100 crosses by making cuts at 1 mm intervals. Cellophane tape (product name: Cellophane tape manufactured by Nichiban Co., Ltd.) was applied on the surface of the tape, and then peeled off at a stretch in a direction of 90 degrees from the surface, and the adhesiveness was evaluated by the number of eyes left on the surface. Therefore, 100/100 is completely bonded, 0/1
00 means complete peeling. (Based on JIS K5400)

(2) Scratch hardness: With the hand of the measurer, the pencil was moved forward while pressing the cylindrical core while keeping the pencil at an angle of about 45 degrees with respect to the surface of the test piece. The hardness was evaluated by the hardness of a hard pencil. (JIS K5
According to 400)

(3) Abrasion resistance: A Taber abrasion tester (manufactured by Toyo Seiki Co., Ltd.) was used to abrade the surface of the test piece under the conditions of an abrasion wheel CS-10F, a load of 500 g, and 500 cycles. Difference in required haze value before and after abrasion (Δ haze value)
Was evaluated. (JIS K6735 or ASTM D10
44)

[0108]

[Equation 1] Haze value (%) = (diffuse transmittance / total light transmittance) × 100

(4) Scratch resistance: The surface of the test piece was # 0000.
After rubbing with steel wool, the state of scratches on the surface was visually evaluated in the following 5 grades. 0: No scratch even if rubbed strongly 1: Slightly scratched when rubbed strongly 2: Slightly scratched when rubbed strongly 3: Scratched when strongly rubbed 4: Even scratched when weakly rubbed

(5) Boiling resistance: The test pieces were boiled in tap water for 2 hours or 5 hours, and the appearance change, adhesion and scratch resistance of the coating film were evaluated.

[Example 1] (Composition for first layer) 4.0 parts of methyltrimethoxysilane was placed in an Erlenmeyer flask, and a solution of 0.4 parts of acetic acid and 1.9 parts of water was stirred while being externally cooled. Added below. After continuing stirring at room temperature for about 1 hour, 12 parts of isopropanol (hereinafter abbreviated as IPA) and 0.04 part of sodium acetate were added to the reaction solution. Further, stirring was continued at room temperature for about 24 hours. Then, in the reaction solution, the acrylic resin-A1
A composition 1-1 was prepared by dissolving in a mixed solvent of 0 part, 45 parts of sec-butanol and 45 parts of methyl ethyl ketone (hereinafter abbreviated as MEK), and filtering with a 1 μm filter.

(Composition for the second layer) 30.5 parts of methyltrimethoxysilane was placed in an Erlenmeyer flask, and a solution of 3.0 parts of acetic acid and 14 parts of water was added with stirring while externally cooling. After continuing stirring at room temperature for about 1 hour, 20 parts of isopropanol (hereinafter abbreviated as IPA) and 0.3 part of sodium acetate were added to the reaction solution. Further, stirring was continued at room temperature for about 24 hours. Then, a solution of 5.0 parts of the acrylic resin-B and 27 parts of methyl ethyl ketone (hereinafter abbreviated as MEK) was added to and dissolved in the reaction solution. The solution was then aged for 24 hours. A composition 1-2 was prepared by adding 0.2 parts of a polysiloxane-based paint additive Perenol S4 (trade name: San Nopco Ltd.) and filtering through a 1 μm filter.

(Composition for the third layer) A 30% colloidal silica aqueous dispersion (manufactured by Catalysts & Chemicals Co., Ltd .: trade name: Cataloid SI-3) in 30 parts of methyltrimethoxysilane.
0) An acidic dispersion of 20 parts mixed with 3.5 parts acetic acid was added with vigorous stirring under external cooling. Then, after continuing stirring at room temperature for 3 hours, 35 parts of IPA and 0.2 part of sodium acetate were added. The pH value of the system was 5.3. After standing at room temperature for 3 days, the composition 1-3 was prepared by filtering with a 1 μm filter.

(Production and Evaluation of Molded Article) Composition 1-1 was coated on a plate made of poly (bisphenol-A carbonate) resin (hereinafter abbreviated as PC) with a thickness of 3 mm with a # 20 wire bar, and the temperature was kept at room temperature. After allowing it to stand for 20 minutes at the bottom, it was dried at 120 ° C for 30 minutes. The coating film thickness was 2.5 μm. Next, the composition 1-2 was applied on the coating surface of the laminate with a # 50 wire bar, allowed to stand at room temperature for 20 minutes, and then heated at 100 ° C. for 20 minutes. The coating film thickness was 15 μm. Further, the composition 1-3 was applied onto the surface of the laminated film with a # 20 wire bar, left standing at room temperature for 20 minutes, and then heat-cured at 130 ° C. for 1 hour. The coating film thickness in this operation was 5 μm.

The obtained molded product was good in appearance and transparent without cracks. The grid check is 100/100
Showed good adhesion. The pencil hardness was 4H, the Taber abrasion test had a Δ haze value of 1.8%, and the steel wool test had a rating of 0, indicating a very high surface hardness. When the molded body was immersed in boiling water for 5 hours, no change in appearance was observed and the adhesiveness was 100/100. In addition, the result of rubbing the surface after immersion with steel wool was 0, indicating excellent boiling water resistance.

The compositions 1-2 and 1-3 were stably used for coating without gelation for one month or longer.

On the other hand, in the case of the base material PC plate having no protective layer, the pencil hardness was 3B, the Taber abrasion test result was Δhaze value of 48%, and the steel wool test result was 4. .

Comparative Example 1 A cured layer of Composition 1-1 having a thickness of 2.5 μm and Composition 1 were prepared in the same manner as in Example 1 except that Composition 1-2 was not applied onto a 3 mm thick PC plate. -3
The cured layer of 5 μm was sequentially laminated. This molded body was transparent and smooth, and no crack was observed. The adhesiveness is 100/100 in a cross-cut test, and the Taber abrasion test is Δ.
The haze value was 1.8%, and the result of the steel wool test was 0, but the pencil hardness was F. The molded body is
A slight whitening of the coating film was observed after immersion in boiling water for 2 hours, and cracking occurred in the coating film after immersion for 5 hours, and a decrease in adhesion was also observed.

Comparative Example 2 A cured layer of Composition 1-1 and a cured layer of Composition 1-2 having a thickness of 2.5 μm and 15 μm were prepared in the same manner as in Example 1 except that the composition 1-3 was not applied. A PC board molded body that was sequentially laminated was obtained. The molded product had an adhesiveness of 100/100 in a cross-cut test, a pencil hardness of 2H, a Taber abrasion test of Δ haze value of 9%, and a steel wool test result of 2. .

Comparative Example 3 A cured layer of Composition 1-2 and a cured layer of Composition 1-3 were laminated in the same manner as in Example 1 except that the composition 1-1 was not applied. A molded PC plate was obtained. The adhesiveness of the molded product was 0/100 in a cross-cut test. The pencil hardness and Taber abrasion tests could not be evaluated because the coating film peeled off during the measurement.

[Example 2] (Composition for the first layer) 4.0 parts of methyltrimethoxysilane was placed in an Erlenmeyer flask, and a solution of 0.4 parts of acetic acid and 1.9 parts of water was stirred while being externally cooled. Added below. After continuing stirring at room temperature for about 1 hour, 12 parts of IPA and 0.04 part of sodium acetate were added to the reaction solution. Further, stirring was continued at room temperature for about 24 hours. Then, in the reaction solution, it was dissolved in a mixed solvent consisting of 18 parts of the acrylic resin-B, 80 parts of sec-butanol and 80 parts of MEK, and filtered through a 1 μm filter to prepare a composition 2-1.

(Second Layer Composition) A composition 2-2 was prepared in the same manner as in Example 1 except that 5.0 parts of acrylic resin-C was used instead of acrylic resin-B.

(Composition for Third Layer) The above composition 1-3 was used.

(Manufacture and Evaluation of Molded Article) In exactly the same manner as in Example 1, the first layer 5 μm, the second layer 20 μm and the third layer 5.5 μm were sequentially laminated on the PC plate having a thickness of 3 mm. The obtained molded product had a total light transmittance of 91.5%, and the appearance was transparent and good. Adhesiveness is 100/1 in a cross-cut test
The pencil hardness was 5H, the Taber abrasion test result was a Δ haze value of 1.7%, and the steel wool test result was an evaluation of 0. After the boiling water immersion test for 5 hours, the molded product showed no change in appearance, adhesiveness and surface hardness.

Example 3 Composition 2-1 was applied on a polymethylmethacrylate (abbreviated as PMMA) resin plate having a thickness of 2 mm.
Was applied with a # 10 wire bar, allowed to stand at room temperature for 20 minutes, and then dried at 80 ° C. for 30 minutes. Coating thickness is 2.5
μm. Then, the composition 1-2 is applied to the surface of the coating film.
Was applied with a # 40 wire bar, allowed to stand at room temperature for 20 minutes, and then heated at 80 ° C. for 20 minutes. The coating film thickness was 11 μm. Further, the composition 1-3 was coated with # 16 on the surface of the coating film.
Apply it with a wire bar and leave it for 20 minutes at room temperature.
It was heat-cured at ℃ for 4 hours. The coating thickness in this operation is 4
μm. The adhesiveness of the obtained molded product is 100/10.
The surface hardness was 0, the pencil hardness was 7H, the Δhaze value was 2.4% in the Taber abrasion test, and the steel wool test was 0. The coated film did not show any change even after immersion in boiling water for 5 hours.

On the other hand, the surface hardness of the base material PMMA is
The pencil hardness was 2H, the Taber abrasion test had a Δ haze value of 29%, and the steel wool test had an evaluation of 4.

[Example 4] (Composition for the first layer) 4.0 parts of methyltrimethoxysilane was placed in an Erlenmeyer flask, and a solution of 0.4 parts of acetic acid and 1.9 parts of water was stirred while being externally cooled. Added below. After continuing stirring at room temperature for about 1 hour, 12 parts of IPA and 0.04 part of sodium acetate were added to the reaction solution. Further, stirring was continued at room temperature for about 24 hours. Then, in the reaction solution, it was dissolved in a mixed solvent consisting of 15 parts of the acrylic resin-D, 68 parts of sec-butanol and 68 parts of MEK, and filtered through a 1 μm filter to prepare a composition 4-1.

(Composition for the second layer) 28.5 parts of methyltrimethoxysilane was placed in an Erlenmeyer flask, and a solution of 3.0 parts of acetic acid and 12 parts of water was added with stirring while externally cooling. After continuing stirring at room temperature for about 1 hour, 16 parts of IPA and 0.3 part of sodium acetate were added to the reaction solution. Further, stirring was continued at room temperature for about 2 hours. Then, a solution consisting of 6.0 parts of the acrylic resin-A and 42 parts of MIBK was added to the reaction solution, and stirring was further continued for 4 hours. After adding 0.2 parts of the polysiloxane coating additive Perenol S4, the mixture was filtered through a 1 μm filter to prepare a composition 4-2.

(Composition for Third Layer) 40% colloidal silica aqueous dispersion (catalyst chemical industry Co., Ltd .: trade name Cataloid SI-4) in 27 parts of methyltrimethoxysilane.
0) An acidic dispersion prepared by mixing 18 parts, 3.6 parts of water and 4 parts of acetic acid was added with vigorous stirring under external cooling. Next, after continuing stirring at room temperature for 24 hours, 38 parts of IPA and 0.4 part of benzyltrimethylammonium acetate were added. The pH value of the system was 5.2. After standing at room temperature for 2 days, the composition 4-3 was prepared by filtering with a 1 μm filter.

(Manufacture and Evaluation of Molded Article) A first layer of 1.5 μm was formed on a PC plate having a thickness of 3 mm by the dip coating method.
The second layer 10 μm and the third layer 5 μm were sequentially laminated. As a result of evaluating the coating film performance of the obtained molded product, the adhesiveness was 100/100 in a cross-cut test, and the pencil hardness was 3H.
The result of the Taber abrasion test was Δhaze value of 1.5%, and the result of the steel wool test was 0. After the boiling water immersion test for 5 hours, the laminate did not show any change in appearance, adhesiveness and surface hardness.

[Examples 5 to 6] The same procedure as in Example 1 was carried out except that the acrylic resin-E or -F was used in place of the acrylic resin-A in the preparation of the coating composition for the first layer. Then, a PC molded plate was produced. As a result of evaluating the coating film performance of the obtained molded product, the adhesiveness was 100 in the cross-cut test.
/ 100, the pencil hardness was 4H, the result of the Taber abrasion test was ΔHaze value of 1.8%, and the result of the steel wool test was 0. After the boiling water immersion test for 5 hours, the laminate did not show any change in appearance, adhesiveness and surface hardness.

[Example 7] (Composition for the first layer) In composition 1-1 used in Example 1,
Composition exactly as in Example 1 except that 1.0 part of Cymel 303 (methyl ether type hexamethylol melamine resin) manufactured by Mitsui Cytec Co., Ltd. and 0.03 part of p-toluenesulfonic acid were further added and dissolved. 7-1 was prepared.

(Composition for Second Layer) Composition 2-2 was used.

(Composition for Third Layer) The above composition 4-3 was used.

(Manufacture and Evaluation of Molded Article) The first layer of 1.5 μm was formed on a PC plate having a thickness of 3 mm by the dip coating method.
The second layer 10 μm and the third layer 3.5 μm were sequentially laminated.
As a result of evaluating the coating film performance of the obtained molded product, the adhesiveness was 100/100 in a cross-cut test, the pencil hardness was 3H, and the result of the Taber abrasion test was Δhaze value of 1.5%.
The result of the steel wool test was 0. Also,
The coating film did not change at all even after the boiling water test for 5 hours.

[Examples 8 to 10] A PC molded article was produced in exactly the same manner as in Example 1 except that the above acrylic resins -D, -E and -F were used for the second layer. As a result of evaluating the coating film performance of each of the obtained molded products, the adhesiveness was 100/100 in a cross-cut test, the pencil hardness was 4H, and the Taber abrasion test result was Δhaze value of 1.7, respectively.
1.6 and 1.6%, and the result of the steel wool test was 0. After the boiling water immersion test for 5 hours, the laminate did not show any change in appearance, adhesiveness and surface hardness.

[Example 11] (Composition for the first layer) In composition 2-1 used in Example 1,
Mitsui Cytec Co., Ltd. Cymel 303 (methyl ether type hexamethylol melamine resin) (3.0 parts) and p-toluenesulfonic acid (0.1 parts) were added and dissolved.
Composition 11-1 was prepared in exactly the same manner as in Example 2.

(Composition for the second layer) 24.4 parts of methyltrimethoxysilane was placed in an Erlenmeyer flask, and a solution consisting of 2.5 parts of acetic acid and 12 parts of water was added under external cooling while stirring. After continuing stirring at room temperature for about 1 hour, 16 parts of isopropanol (hereinafter abbreviated as IPA) and 0.3 part of sodium acetate were added to the reaction solution. Further, stirring was continued at room temperature for about 24 hours. In the reaction solution, Aldrich (Aldr
ich) poly (2-hydroxyethylmethacrylate) (viscosity average molecular weight of about 300,000) and a solution of 10.0 parts of ethanol and 40 parts of ethanol were added and dissolved, and aging was continued for 24 hours. After adding 0.2 parts of polysiloxane coating additive Perenol S4, a composition 11-2 was prepared by filtering with a 1 μm filter.

(Composition for Third Layer) Composition 1-3 was used.

(Manufacture and Evaluation of Molded Article) In the same manner as in Example 1, the first layer 2 μm, the second layer 15 μm and the third layer 5 μm were sequentially laminated on the PC plate (thickness 3 mm). As a result of evaluating the coating performance of the obtained laminate, the adhesiveness was 100/100 in a cross-cut test, the pencil hardness was 4H, and the result of the Taber abrasion test was Δhaze value of 1.6%. The result of the steel wool test was 0. Also, the coating film is 5
It did not change at all after the boiling water test for hours.

[Examples 12 to 13] 3.0 parts of Cymel 303 (methyl ether type hexamethylol melamine resin) manufactured by Mitsui Cytec Co., Ltd. and p were added to the composition 11-2 for the second layer used in Example 11. -Toluene sulfonic acid 0.1 part (Example 12) or Cymel 370 (methyl ether type hexamethylol melamine resin) 3.0 parts and itaconic acid 0.1 part (Example 13) are added and dissolved, respectively. A PC molded product was produced in exactly the same manner as in Example 11. As a result of evaluating the coating film performance of the obtained molded body, the adhesiveness was 100/100 in the cross-cut test, the pencil hardness was 4H, and the result of the Taber abrasion test was Δhaze value of 1.5 each. It was 1.6%, and the result of the steel wool test was 0. After the boiling water immersion test for 5 hours, the molded product showed no change in appearance, adhesiveness and surface hardness.

Example 14 (Composition for First Layer) The composition 1-1 was used.

(Composition for Second Layer) The composition 1-2 was used.

(Third Layer Composition) 20 parts of tetramethoxysilane was dissolved in 7 parts of IPA, and 10 parts of 0.01N hydrochloric acid aqueous solution was added thereto while vigorously stirring under external cooling. Then, the mixture was stirred at room temperature for 3 hours, and then left standing at 10 ° C. for 24 hours or more for aging to prepare a sol-gel reaction solution of tetramethoxysilane. 13.6 parts of methyltrimethoxysilane was mixed with 3 parts of the sol-gel reaction liquid, and 5.4 parts of 0.01N hydrochloric acid aqueous solution was added thereto while vigorously stirring under external cooling. Then, after stirring at room temperature for 3 hours, IPA 8.9
Parts, 1.8 parts of 10% sodium acetate acetic acid solution were added. The pH value of the system was 5.2. After standing at room temperature for 3 days, the composition 14-3 was prepared by filtering with a 1 μm filter.

(Manufacture and Evaluation of Molded Product) PC thickness 3 mm
The composition 1-1 was applied to the plate of No. 2 with a # 20 wire bar, allowed to stand at room temperature for 20 minutes, and then dried at 120 ° C. for 30 minutes. The coating film thickness was 2.5 μm. Then, the composition 1-2 was applied onto the coating surface of the laminate with a # 50 wire bar, allowed to stand at room temperature for 20 minutes, and then heated at 80 ° C. for 20 minutes. The coating film thickness was 15 μm. Further, the composition 14-3 was applied onto the surface of the laminated film with a # 20 wire bar, allowed to stand at room temperature for 20 minutes, and then heat-cured at 120 ° C. for 1 hour. The coating film thickness in this operation was 4.5 μm.

The obtained molded product was good in appearance and transparent without cracks. The grid check is 100/100
Showed good adhesion. The pencil hardness was 4H, the Taber abrasion test had a Δ haze value of 4.5%, and the steel wool test had a rating of 0, indicating a very high performance surface hardness. When the laminate was immersed in boiling water for 5 hours, no change in appearance was observed and the adhesiveness was 100/100. In addition, the result of rubbing the surface after immersion with steel wool was 0, indicating excellent boiling water resistance.

Compositions 1-2 and 1-3 were used stably for coating without gelation for one month or longer.

[Example 15] (Composition for the first layer) The composition 4-1 was used.

(Composition for Second Layer) The composition 4-2 was used.

(Composition for Third Layer) To 20 parts of tetraethoxysilane, 7 parts of a 0.01N hydrochloric acid aqueous solution was added with vigorous stirring under external cooling. Then, stirring was continued at room temperature for 3 hours, and then the mixture was allowed to stand at 10 ° C. for 24 hours or more for aging to prepare a sol-gel reaction solution of tetraethoxysilane. 28 parts of methyltrimethoxysilane was mixed with 3 parts of the sol-gel reaction solution, and 11.1 parts of 0.01 N hydrochloric acid aqueous solution was added thereto while vigorously stirring under external cooling. Then, after stirring at room temperature for 3 hours, 18.5 parts of IPA and 3.5 parts of a 10% sodium acetate acetic acid solution were added. The pH value of the system was 5.2. After standing at room temperature for 3 days, it was filtered through a 1 μm filter to prepare a composition 15-3.

(Manufacture and Evaluation of Molded Article) The first layer of 1.5 μm was formed on a PC plate having a thickness of 3 mm by the dip coating method.
The second layer 10 μm and the third layer 5 μm were sequentially laminated. As a result of evaluating the coating film performance of the obtained molded product, the adhesiveness was 100/100 in a cross-cut test, and the pencil hardness was 3H.
The result of the Taber abrasion test was Δ Δ haze value of 4.2%, and the result of the steel wool test was 0. Further, after the boiling water immersion test for 5 hours, the molded product showed no change in appearance, adhesiveness and surface hardness.

[Example 16] (Composition for first layer) The composition 7-1 was used.

(Composition for Second Layer) The composition 4-2 was used.

(Composition for the third layer) 20 parts of tetramethoxysilane was dissolved in 3 parts of IPA, 2 parts of acetic acid and 12 parts of water were added.
Parts were added under external cooling with vigorous stirring. Then, the mixture was stirred at room temperature for 3 hours, and then left standing at 10 ° C. for 24 hours or more for aging to prepare a sol-gel reaction solution of tetramethoxysilane. 6 parts of methyltrimethoxysilane was mixed with 3 parts of the sol-gel reaction solution, and 0.6 part of acetic acid and 3.0 parts of water were added with vigorous stirring under external cooling. Then, after stirring at room temperature for 3 hours, 4 parts of IPA and 2 parts of benzyltrimethylammonium acetate were added. After standing at room temperature for 6 days, it was filtered through a 1 μm filter to prepare a composition 16-3.

(Manufacture and Evaluation of Molded Product) A first layer of 1.5 μm was formed on a PC plate having a thickness of 3 mm by the dip coating method.
The second layer 10 μm and the third layer 3.5 μm were sequentially laminated.
As a result of evaluating the coating film performance of the obtained molded product, the adhesiveness was 100/100 in a cross-cut test, the pencil hardness was 3H, and the result of the Taber abrasion test was Δhaze value of 3.2%.
The result of the steel wool test was 0. Also,
The coating film of the molded body did not change even after the boiling water test for 5 hours.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location C09D 133/14 PGC C09D 133/14 PGC 183/06 PMT 183/06 PMT

Claims (6)

[Claims] 1. A surface of a plastic substrate is represented by the following formula (A): R ² _n —Si (OR ³ ) _4-n ... (A) [wherein R ² has 1 to 10 carbon atoms. 4 is an organic group having at least one group selected from the group consisting of an alkyl group, a vinyl group, a methacryloxy group, an amino group, an epoxy group, and a mercapto group, and R ³ is an alkyl group having 1 to 4 carbon atoms. , N is an integer of 0-2. ] A (partial) hydrolyzate of alkoxysilane, a partial condensate thereof, or a mixture thereof of 1 to 40% by weight (based on the weight of R ² _n SiO _{(4-n) / 2) represented} by the following formula (B1 ) And (B2) [Wherein, X is a hydrogen atom or a methyl group, R ⁴ is an alkylene group having 2 to 5 carbon atoms, and R ⁵ is 1 to 1 carbon atoms.
4 alkyl group. ] The molar ratio (p / q) of the repeating units (B1) and (B2) is 99% to 60% by weight of the acrylic resin (I) which is mainly composed of the repeating unit represented by A first layer formed by reaction heat curing of a mixture or a reaction product, a (partial) hydrolyzate of an alkoxysilane represented by the above formula (A), a partial condensate thereof or a mixture thereof 40 to 90% by weight (R ² _n SiO
₍ Weight basis by _{(4-n) / 2} conversion) and the following formulas (C1) and (C2) [Wherein, X is a hydrogen atom or a methyl group, R ⁴ is an alkylene group having 2 to 5 carbon atoms, and R ⁵ is 1 to 1 carbon atoms.
4 alkyl group. ] 60 to 10% by weight of an acrylic resin (II) which is mainly composed of a repeating unit represented by the formula (1) and has a molar ratio (r / s) of the repeating units (C1) and (C2) of 1/99 to 100/0. A second layer formed by reaction heat curing of a mixture or a reaction product, represented by the following formula (E): embedded image R ⁹ _v —Si (OR ¹⁰ ) _4-v (E) [wherein R ⁹ is An alkyl group having 1 to 4 carbon atoms, a vinyl group, or an alkyl group having 1 to 3 carbon atoms substituted with one or more groups selected from the group consisting of a methacryloxy group, an amino group, and a glycidoxy group, and R ¹⁰ is carbon It is an alkyl group of the numbers 1 to 4, and v is an integer of 0 to 2. ] A third layer obtained by thermosetting an organopolysiloxane resin comprising a (partial) hydrolyzate of alkoxysilane, a partial condensate thereof, or a mixture thereof represented by the following formula is sequentially laminated from the first layer. A characteristic molded plastic body with a protected surface. 2. The third layer has the following formula (D): R ⁷ —Si (OR ⁸ ) ₃ (D) [wherein R ⁷ is an alkyl group having 1 to 4 carbon atoms, A vinyl group, or an alkyl group having 1 to 3 carbon atoms substituted with one or more groups selected from the group consisting of methacryloxy group, amino group and glycidoxy group, and R ⁸ is an alkyl group having 1 to 4 carbon atoms. . ] (Partial) hydrolyzate of trialkoxysilane, its partial condensate or a mixture thereof represented by 90 to 30% by weight (based on the R ⁷ SiO _3/2 basis) and 10 to 70% by weight of colloidal silica. The surface-protected plastic molded article according to claim 1, which comprises a layer obtained by thermosetting an organopolysiloxane resin. 3. The surface-protected plastic molded product according to claim 2, wherein at least 70% by weight of the trialkoxysilane used for forming the third layer is methyltrialkoxysilane. 4. The surface according to claim 1, wherein the alkoxysilane used for forming the third layer is mainly composed of 40 mol% or less of tetraalkoxysilane and 60 mol% or more of trialkoxysilane. The protected plastic molding. 5. The surface-protected plastic molded product according to claim 1, wherein the plastic substrate is a polycarbonate resin. 6. A composition containing a mixture or reaction product of a (partial) hydrolyzate of an alkoxysilane, a partial condensate thereof or a mixture thereof and an acrylic resin having a hydroxyl group is applied onto a plastic substrate. Then, by heating, a first layer is formed, and a mixture or reaction of a (partial) hydrolyzate of an alkoxysilane, a partial condensate thereof or a mixture thereof with an acrylic resin having a hydroxyl group on the first layer. Characterized in that a composition containing a compound is applied, and then a second layer is formed by heating, a composition containing an organopolysiloxane resin is applied on the second layer, and then a third layer is formed by heating. A method for producing a plastic molded product whose surface is protected.