JPH08309934A - Surface protected plastic molding and method for producing the same - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a durable plastic molded article having high abrasion resistance, scratch hardness and solvent resistance. [Structure] On the surface of a plastic substrate, a first layer made of a methacrylate acrylic resin, an alkoxysilane, a (partial) hydrolyzate thereof, a partial condensate thereof or a mixture thereof, and a methylmethacrylate monomer and trimethylvinylsilane A second layer obtained by reaction thermosetting of an acrylic resin made of a copolymer with an alkoxysilyl group-containing vinyl monomer and a third layer obtained by thermosetting an organopolysiloxane resin are sequentially laminated from the first layer. A plastic molded article whose surface is protected, which is characterized by:

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, a plastic molded product having a remarkably improved surface hardness by sequentially laminating an acrylic resin layer, a cured product layer of an acrylic resin and an organopolysiloxane, and a cured organopolysiloxane layer on the surface of a plastic substrate. And a manufacturing method thereof.

[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 (JP-A-62-62).
-275170). 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.

Further, a urethane coating film, a photo-curing film of a polyfunctional acrylate resin, and an organopolysiloxane thermosetting film are sequentially laminated on a substrate to improve both scratch hardness and abrasion resistance of the plastic. Method (JP-A-58-8)
9359). In this way,
The photo-curing 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.

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 (Japanese Patent Laid-Open No. 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.

[0007]

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 intended to provide a plastic molded product having good durability and a method for producing the same.

[0008]

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 wear resistance and scratch hardness, and further having excellent adhesion durability can be obtained, and thus reached the present invention.

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

[0010]

[Chemical 7]

[Wherein R ¹ is an alkyl group having 1 to 4 carbon atoms. ] A first layer comprising a polymethacrylate acrylic resin (I) containing 50 mol% or more of the repeating unit represented by the following formula (B):

[0012]

Embedded image R ² _n —Si (OR ³ ) _4-n ---------- (B) [wherein R ² is an alkyl group having 1 to 4 carbon atoms, a vinyl group, or An organic group having at least one group selected from the group consisting of a methacryloxy group, an amino group, an epoxy group and a mercapto group, R ³ is an alkyl group having 1 to 4 carbon atoms, and n is an integer of 0 to 2. is there. ] A (partial) hydrolyzate of alkoxysilane, a partial condensate thereof or a mixture thereof represented by 50 to 90% by weight (based on R ² _n SiO _{(4-n) / 2} ) based on the following formula (C ) And (D)

[0013]

[Chemical 9]

[Wherein, X is a hydrogen atom or a methyl group, R ⁴ and R ⁵ are each independently an alkyl group having 1 to 4 carbon atoms, and m is an integer of 0 or 1. ] And the molar ratio (p / q) of such repeating units (C) and (D) is 99.99 /
A second layer obtained by reaction thermosetting a mixture or reaction product of acrylic resin (II) having an alkoxysilyl group of 0.01 to 50/50 with 50 to 10% by weight, and thermosetting the organopolysiloxane resin. A third aspect of the present invention is a plastic molded article having a protected surface, which is formed by sequentially laminating the third layer from the first layer.

In the present invention, the composition containing the acrylic resin (I) is applied onto a plastic substrate and then heated to form a first layer, and the alkoxysilane (part) is formed on the first layer. ) A composition containing a hydrolyzate, a partial condensate thereof or a mixture thereof and a mixture or a reaction product of the above-mentioned acrylic resin (II) having an alkoxysilyl group is applied, and then the second layer is formed by heating. A method for producing a plastic molded article having a protected surface, characterized in that the composition containing the organopolysiloxane resin is applied onto the second layer, and then the third layer is formed by heating.

The acrylic resin (I) constituting the first layer in the present invention is a polymethacrylate resin whose repeating unit has a structure represented by the following formula (A) in an amount of 50 mol% or more.

[0017]

[Chemical 10]

Here, R ¹ in the formula is an alkyl group having 1 to 4 carbon atoms such as a methyl group and an ethyl group. Examples of such a resin include a homopolymer of polyalkyl methacrylate or 50 mol% or more of alkyl methacrylate and 50 mol% or more.
The following copolymers with other vinyl monomers are preferred. The other vinyl monomer is not particularly limited as long as it can be copolymerized, but acrylic acid, methacrylic acid or derivatives thereof are preferable from the viewpoint of durability such as adhesiveness or weather resistance. Specifically, acrylic acid, methacrylic acid, acrylic acid amide, methacrylic acid amide, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate,
Butyl acrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2
-Hydroxypropylmethacrylate, N, N-diethylaminoethylmethacrylate, glycidylmethacrylate, and an alkoxysilyl group such as 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane Vinyl monomers may be mentioned. The copolymer with the vinyl monomer containing an alkoxysilyl group has the following formulas (A) and (G)

[0019]

[Chemical 11]

A copolymer of a methacrylate-based monomer and a methacrylate-based monomer having an alkoxysilyl group, which is composed of a repeating unit represented by the following formula, can be preferably used.

In the formula, R ¹ is an alkyl group having 1 to 4 carbon atoms. R ¹⁰ is an alkyl group having 1 to 4 carbon atoms,
l is an integer of 0 or 1.

When the molar amounts of the repeating units represented by the above formulas (A) and (G) are r and s, the above copolymer has a molar ratio r / s of 99.99 / 0.01 to 50. / 5
It is preferably 0. By copolymerizing the methacrylate-based monomer having an alkoxysilyl group with the methacrylate-based monomer, the adhesiveness with the second layer is further enhanced, so that the durability of the molded product in the boiling water immersion is further improved. However, when the amount of the methacrylate-based monomer having the alkoxysilyl group is more than half of the total amount of the copolymerization components, the copolymer is apt to gel and lacks storage stability, and similarly the adhesiveness in boiling water diminishes. There is. The molar ratio r / s of such a copolymer is more preferably 99/1 to 60/40, and further preferably 97.
/ 3 to 70/30.

Further, the copolymer is the R in the above formula (A).
¹ is a methyl group or an ethyl group, and R in the above formula (G)
More preferably, ¹⁰ is a methyl group and l is 0.

Since such a copolymer has an alkoxy group, it is structurally similar to the second layer to be described later and has an affinity, so that it is presumed that the adhesiveness with the second layer is further enhanced. It

The above acrylic resin may contain a single repeating unit represented by the above formula (A) or a combination of two or more thereof. Further, a ternary compound containing the repeating unit represented by the above formula (A) alone or in combination of two or more, and using as the copolymerization component one or more of the vinyl monomers listed above. It may be a copolymer of a system or more.

The acrylic resin used in the present invention may be a single kind or a blend of two or more kinds.

The molecular weight of the above acrylic resin 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.

As a method for forming the first layer by coating the acrylic resin (I) used in the present invention on a plastic substrate, a composition comprising the above acrylic resin and an inert volatile solvent is usually used. The coating is applied to the surface of the base material, and then the solvent is dried and removed by heating or the like. Examples of such an inert and volatile solvent, that is, a solvent that does not react with or dissolve the plastic as the base material, include water, methanol, ethanol, isopropanol, n-butanol, sec-butanol, and amyl. Alcohols, alcohols such as methoxyethanol, ethoxyethanol, butoxyethanol, diacetone alcohol, ethyl formate, ethyl acetate,
Butyl acetate, ethoxyethyl acetate, butoxyethyl acetate, ethylene glycol diacetate and other esters, n-hexane, n-heptane, isooctane, benzene, toluene, xylene and other hydrocarbons, diethyl ether, tetrahydrofuran, 1,4-
Ethers such as dioxane, 1,3-dioxolane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, acetone, methyl ethyl ketone,
Examples thereof include ketones such as methyl isobutyl ketone and cyclohexanone, acetonitrile, and nitromethane. These solvents can be used as a mixture of two or more kinds. Usually, in such a composition, the acrylic resin is 1 to 40% by weight,
It is preferably contained in an amount of 3 to 30% by weight.

Further, the above 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 UV absorber include benzophenones such as 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-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 above-mentioned composition containing an acrylic resin is applied to a plastic substrate by a commonly used method such as dip coating, spray coating, flow coating, roll coating, bar coating and spin coating. It can be appropriately selected depending on the shape and the like. The base material coated with such a composition is usually dried at room temperature to a temperature not higher than the heat deformation temperature of the base material to remove the solvent, whereby the acrylic resin layer forming the first layer in the present invention is obtained.

The thickness of such an acrylic resin layer is a film necessary for sufficiently adhering the plastic base material to the second and subsequent layers in the present invention, and for holding the necessary amount of the above weather resistance improver. It may have any thickness, and is usually 0.1 to 10 μm, preferably 1 to 5 μm.

By forming the first layer of the acrylic resin, the adhesion between the second layer, which will be described later, and the plastic base material becomes good, and a plastic molded product having excellent durability can be obtained.

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

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

[0037]

Embedded image R ² _n —Si (OR ³ ) _4-n ---------- (B) wherein R ² is an alkyl group having 1 to 4 carbon atoms, a vinyl group, or An organic group having at least one group selected from the group consisting of a methacryloxy group, an amino group, an epoxy group, and a mercapto group, R ³ is an alkyl group having 1 to 4 carbon atoms, and n is an integer of 0 to 2. . Such an organic group is an aliphatic hydrocarbon group having 1 to 10 carbon atoms which can include a cyclic structure, and the hydrocarbon group has a part of the carbon atoms thereof as a hetero atom such as an oxygen atom or a nitrogen atom. It may be replaced.

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. Among them, alkyltrialkylsilanes such as methyltrimethoxysilane and methyltriethoxysilane are preferable in terms of scratch resistance and crack resistance of the cured film obtained. 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 so-called sol-gel reaction.

The above-mentioned (partial) hydrolyzate of alkoxysilane and its partial condensate are usually 0.2 to 5 times equivalent, preferably 0.5 to 2.5 times, equivalent to 1 equivalent of alkoxy group with respect to alkoxysilane. Equivalent, and more preferably 0.8-1.
It can be obtained by adding 5 times equivalent water and diluting with or without a solvent in the presence of an acid catalyst. The sol-gel reaction liquid containing the (partial) hydrolyzate of the alkoxysilane thus obtained, its partial condensate, or a mixture thereof is
It is usually used after aging. 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.

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. Hydrochloric acid and acetic acid are preferable, and acetic acid is particularly preferable, from the viewpoint of catalytic effect, stability of the coating composition, and residual property when formed into a cured film. The inorganic acid has a concentration of usually 0.0001 to 2N, preferably 0.001 to 1N, and the organic acid usually has a concentration of 0.1 to 50% by weight, preferably 1 to 50% with respect to the alkoxysilane.
Used at 20% by weight.

The solvent (diluting 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-mentioned 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
One or more species can be used in combination.

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

The acrylic resin (II) having an alkoxysilyl group used for constituting the second layer of the present invention is a methacrylate-based copolymer consisting essentially of repeating units represented by the following formulas (C) and (D). It is a polymer.

[0046]

[Chemical 13]

In the formula, X is a hydrogen atom or a methyl group, R ⁴ and R ⁵ are each independently an alkyl group having 1 to 4 carbon atoms, and m is an integer of 0 or 1.

The acrylic resin is a copolymer of alkylmethacrylate and vinylalkoxysilane. Examples of the silyl group-containing vinyl monomer for deriving the repeating unit represented by the above formula (D) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltrin-butylsilane, vinylmethyldimethoxysilane, and vinyl. Examples thereof include methyldiethoxysilane, vinylmethyldi-n-propoxysilane, vinyldimethylmethoxysilane, vinyldimethylisobutoxysilane and the like. Vinyltrimethoxysilane is particularly preferable in terms of the performance and economy of the resulting copolymer. These compounds may be used alone or in combination of two or more.

The composition (p / q) of the copolymer consisting essentially of the repeating units represented by the above formulas (C) and (D) is
The molar ratio is 99.99 / 0.01 to 50/50, preferably 98/2 to 70/30. When the silyl group-containing monomer unit is less than 0.01 mol%, that is, the repeating unit (q) represented by the above formula (D) is 0.01
If it is less than mol%, the unit has poor compatibility with the (partial) hydrolyzate of the alkoxysilane, its partial condensate, or a mixture thereof, and the resulting cured film is devitrified or whitened, and has a sufficient scratch hardness. I can't get it. Further, when the amount of the silyl group-containing monomer unit is more than 50 mol%, that is, when q exceeds 50 mol%, the above composition tends to gel and the storage stability is poor.

The weight average molecular weight of the acrylic resin is preferably 20,000 to 600,000, more preferably 40,000 to 400,000. When the molecular weight is less than 20,000, the coating property and the flexibility of the obtained film are low, and cracks are likely to occur, resulting in 600,00.
If it is higher than 0, the stability of the coating composition described below may be reduced.

The acrylic resin has the formula (C)
And substantially consisting of the repeating units represented by (D) alone or in combination of two or more. Formula (C) above,
The repeating unit other than the repeating unit represented by (D) is
For the purpose of enhancing adhesiveness, solubility, durability, etc. without impairing its original performance, 30 mol% or less of all repeating units,
The repeating unit derived from another vinyl monomer can be contained in a proportion of preferably 15 mol% or less.

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

The above-mentioned acrylic resin can be obtained by vinyl-copolymerizing an alkyl methacrylate and the above-mentioned silyl group-containing vinyl monomer by any known method, but it is random copolymerizable and does not contain ionic impurities. Preferably, it is produced by a radical copolymerization method in an inert solvent.

Inert solvent (polymerization solvent) used at that time
Examples include hydrocarbons such as benzene, toluene, xylene, cyclohexane and hexane, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, 1,
Ethers such as 2-dimethoxyethane, 1,3-dioxane and tetrahydrofuran, esters such as ethyl acetate, butyl acetate and ethoxyethyl acetate, methanol, ethanol, isopropanol, n-
Examples include alcohols such as 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. The polymerization temperature and the polymerization time cannot be generally specified because they depend on the initiator used, but usually 50.
~ 100 ° C, preferably 60-80 ° C for 2-24 hours,
It is preferably 4 to 10 hours.

The second layer in the present invention comprises a sol-gel reaction liquid containing the above (partial) hydrolyzate of alkoxysilane, its partial condensate or a mixture thereof, and the above acrylic resin (II) having a specific functional group. It is formed by mixing with a dissolved solution, preferably standing at room temperature for several hours or more, and then using this as a coating composition. By coating with the coating composition that has been left at room temperature for several hours or longer, a transparent and uniform cured film without cracks can be obtained. For this reason, if you leave it like this, (part)
It is presumed that the hydrolyzate, its partial condensate or their mixture (sol-gel reaction product) partially reacts with the alkoxysilyl group of the side chain of the acrylic resin having the above-mentioned specific functional group to be micro-homogenized. To be done.

The above-mentioned (partial) hydrolyzate of alkoxysilane, its partial condensate or a mixture thereof (sol-gel reaction product) and such an acrylic resin are mixed in a proportion of 50 to 90% by weight, preferably 60% by weight. -80% by weight (however, calculated on the basis of weight by R ² _n SiO _{(4-n) / 2} conversion), the latter is 50-10% by weight, preferably 40-20
% By weight. If the amount of the sol-gel reaction product exceeds 90% by weight, cracks are likely to occur in the cured film, and if it is less than 50% by weight, the stability of the coating composition decreases and the cured film has insufficient scratch hardness.

As a solvent for dissolving the acrylic resin,
After mixing with a sol-gel reaction liquid containing such a sol-gel reaction product,
It is sufficient that it can dissolve both components of the acrylic resin and the sol-gel reaction liquid and does not impair the stability of the sol-gel reaction product. 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 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 to form 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-mentioned specific functional group (hereinafter referred to as solid content). 3) to 50% by weight, preferably 5 to 35% by weight, and the total amount of the solvent may be derived from a solution containing the sol-gel reaction solution and an acrylic resin. Alternatively, it may be newly added. The solvent is selected from the solvents that dissolve the above acrylic resin. Also, at least about 1 of the total amount of solvent
It is desirable that 0% by weight or more, preferably about 20% by weight, be selected from the above alcohol solvents.

The above-mentioned coating composition is usually used as a curing catalyst formic acid, acetic acid, propionic acid, butyric acid, lactic acid, tartaric acid,
Lithium salt of aliphatic carboxylic acid such as succinic acid, alkali metal salt such as sodium salt and potassium salt, quaternary ammonium salt such as benzyltrimethylammonium salt, tetramethylammonium salt and tetraethylammonium salt,
It preferably contains sodium acetate, potassium acetate, tetramethylammonium acetate and 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, 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, dip coating, spray coating, flow coating, roll coating, bar coating,
A commonly used method such as spin coating is used, and can be appropriately selected depending on the shape of the substrate. The coated molded body is usually subjected to dry removal of the solvent at room temperature to a temperature not higher than the heat distortion temperature of the substrate, and then 40 to 140 ° C.
By heating (and reacting) for 10 minutes to 4 hours at this temperature, a composite film of the second layer of the present invention, which is an organopolysiloxane and an acrylic resin having an alkoxysilyl group, is formed.

Part or all of the heat curing can also serve as the heat curing of a third layer, which will be described later, which is laminated on the second layer.

The thickness of the second layer formed on the first layer varies depending on the required scratch hardness, but is usually 3 to 50 μm.
m, preferably 5 to 40 μm, more preferably 10 to
It is 30 μm. If the film thickness is smaller than 3 μm, the scratch hardness improving effect cannot be obtained, and if it is larger than 50 μm, cracks are likely to occur.

The composite film constituting the second layer in the present invention has good adhesiveness to the above-mentioned first layer and the third layer described later, and is a plastic molding excellent in durability during boiling water. You can get the body.

The third layer in the present invention is a thin film layer obtained by thermosetting an organopolysiloxane resin.

The third layer contains, for example, a (partial) hydrolyzate of trialkoxysilane represented by the following formula (E), a partial condensate thereof or a mixture thereof and colloidal silica as a substantial solid content, and a solvent. , A coating composition consisting of an acid and a small amount of a curing catalyst.

[0070]

Embedded image R ⁶ —Si (OR ⁷ ) ₃ ---------- (E) wherein R ⁶ is an alkyl group having 1 to 4 carbon atoms, a vinyl group, or a methacryloxy group, It is an alkyl group having 1 to 3 carbon atoms substituted with one or more groups selected from the group consisting of an amino group and a glycidoxy group, and R ⁷ is an alkyl group having 1 to 4 carbon atoms.

Examples of the trialkoxysilane represented by the above formula (E) include methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, methyltrin-butoxysilane, ethyltrimethoxysilane and ethyltriethoxysilane. , Ethyltriisopropoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, methacryloxymethyltrimethoxysilane 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 to 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 R ⁶ SiO _3/2 weight basis), 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.

As another preferred embodiment of the third layer,
For example, a coating composition containing a (partial) hydrolyzate of an alkoxysilane represented by the following formula (F), a partial condensate thereof or a mixture thereof as a substantial solid content, and comprising a solvent, an acid and a small amount of a curing catalyst. It is formed using a thing.

[0076]

Embedded image R ⁸ _v —Si (OR ⁹ ) _4-v ---------- (F) wherein R ⁸ is an alkyl group having 1 to 4 carbon atoms, a vinyl group, or 1 to 3 carbon atoms substituted with one or more groups selected from the group of methacryloxy group, amino group and glycidoxy group
R ⁹ is an alkyl group having 1 to 4 carbon atoms, and v is an integer of 0 to 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-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane and the like can be mentioned. Of these, methyltrialkoxysilane, in terms of wear resistance and crack resistance of the obtained cured film,
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 second layer.

The (partial) hydrolyzate of the alkoxysilane represented by the above formulas (E) and (F) and the partial condensate thereof are usually 0.6 to 5 times as much as 1 equivalent of the alkoxy group of the alkoxysilane. Equivalent, preferably 0.8 to 3.5 times equivalents, more preferably 1 to 2 times equivalents of water is added, and obtained by reacting in the presence of an acid catalyst, without solvent or under dilution with a solvent. You can In the case of the trialkoxysilane represented by the above formula (E), 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. , If necessary, 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.

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. 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 of the present invention is applied onto a plastic molded body in which the first layer and the second layer of the present invention are sequentially laminated and heated to form the third layer. To apply such a coating composition, a commonly used method such as dip coating, spray coating, flow coating, roll coating, bar coating, or spin coating is used,
It can be appropriately selected depending on the shape of the molded body. 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 50-150
Heat curing at a temperature of ℃ for 10 minutes to 4 hours, the residual silanol is condensed in this process, the abrasion-resistant and solvent-resistant thin film of the third layer in the present invention, the first layer and the first layer on the plastic molded body. It is firmly adhered through the two layers.

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

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. 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. Polycarbonate resins such as polybisphenol-A carbonate and acrylic resins such as polymethylmethacrylate are preferable, and poly (bisphenol-A carbonate) is particularly preferable, from the viewpoint of usefulness of the obtained coating effect and adhesion to the substrate.

[0091]

The surface-protected plastic molded product of the present invention thus obtained is a three-layered structure in which the sol-gel reaction product and an acrylic resin having an alkoxysilyl group are reacted and thermally cured to form a second layer. By configuring the structure, a molded article having high durability, abrasion resistance, scratch hardness, and solvent resistance can be obtained. Such molded products include, for example, windows of aircraft, vehicles, automobiles, headlight lenses, etc., windows of construction machinery, optical lenses, mirrors, glasses, goggles, etc.
Sound insulation walls, traffic light lenses, curve mirrors, buildings,
It can be preferably used for homes, garages, greenhouses, windows such as arcades, roofs, windshields, name plates, and other various sheets and films.

[0092]

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 9 (Synthesis Examples of Acrylic Resins A to I) a) Methyl methacrylate (hereinafter abbreviated as MMA) was placed in a flask equipped with a reflux condenser and a stirrer and purged with nitrogen.
95.1 parts, 3-methacryloxypropyltrimethoxysilane (hereinafter abbreviated as MPTMS) 12.4 parts, azobisisobutyronitrile (hereinafter abbreviated as AIBN) 0.16 parts, and 1,2-dimethoxyethane 200 parts Added and dissolved. Then, the mixture was reacted in a nitrogen stream at 70 ° C. for 6 hours with stirring. The obtained reaction system was reprecipitated and refined in n-hexane to obtain 95 parts of a copolymer (acrylic resin-A) having an MMA / MPTMS composition ratio of 95/5 (molar ratio). The weight average molecular weight of the polymer was 150,000 as measured by GPC.
Met. Similarly, MMA / MPTMS composition ratio 9
Copolymer of 0/10 (molar ratio) (acrylic resin-
B), a copolymer of 75/25 (molar ratio) (acrylic resin-C) was synthesized. Weight average molecular weight is 30 each
It was 50,000 and 60,000.

B) 100 parts of ethyl methacrylate (hereinafter abbreviated as EMA), 11.5 parts of MPTMS, AIBN0.
95 parts of a copolymer (acrylic resin-D) having an EMA / MPTMS composition ratio of 95/5 (molar ratio) was obtained in the same manner as in the above a) except that 16 parts and 240 parts of 1,2-dimethoxyethane were used. The weight average molecular weight of the polymer is 18
It was 10,000.

C) 90 parts of MMA, 6.9 parts of ethyl acrylate (hereinafter abbreviated as EA), 1.5 parts of acrylic acid (hereinafter abbreviated as AA), 0.14 parts of AIBN and 20 parts of toluene.
Same as a) above except that 0 parts are used, MMA / E
A / AA composition ratio 90/8/2 (molar ratio) copolymer 9
3 parts (acrylic resin-E) were obtained. The weight average molecular weight of the polymer was 160,000.

D) Polyethylmethacrylate 92 parts (acrylic resin-F) was obtained in the same manner as in the above a) except that 100 parts of EMA, 0.12 part of AIBN and 200 parts of toluene were used. The weight average molecular weight of the polymer is 200,
It was 000.

E) 80.1 parts of MMA, 28.7 parts of vinyltrimethoxysilane (hereinafter abbreviated as VTMS), 0.16 parts of azobisisobutyronitrile (hereinafter abbreviated as AIBN) and 200 parts of 1,2-dimethoxyethane. In the same manner as in the above a) except that is used, the MMA / VTMS composition ratio 9
90 parts of 5/5 (molar ratio) copolymer (acrylic resin-
G) was obtained. The weight average molecular weight of the polymer was 120,000 as measured by GPC.

Similarly, an MMA / VTMS composition ratio of 85
/ 15 (molar ratio) copolymer (acrylic resin-H) was synthesized. The weight average molecular weight was 60,000.

F) EMA 93.4 parts, VTMS 25.5
Parts, AIBN 0.16 parts and 1,2-dimethoxyethane 240 parts were used in the same manner as in the above a) except that EM was used.
Copolymer 9 with A / VTMS composition ratio of 95/5 (molar ratio)
5 parts (acrylic resin-I) were obtained. The weight average molecular weight of the polymer was 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)

[0104]

[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 water 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 the first layer) 10 parts of the acrylic resin-A was separated.
Dissolve in a mixed solvent consisting of 45 parts of c-butanol and 45 parts of methyl isobutyl ketone (hereinafter abbreviated as MIBK) to give 1
A composition 1-1 was prepared by filtering with a 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 3 hours. Then, to the reaction solution, a solution containing 5.0 parts of the acrylic resin-G and 27 parts of MIBK was added,
Further stirring was continued for 12 hours. Polysiloxane paint additive Perenol S4 (trade name: manufactured by San Nopco Ltd.) 0.
After adding 2 parts, the composition was filtered through a 1 μm filter to give a composition 1-2.
Was prepared.

(Composition for the third layer) A 30% colloidal silica aqueous dispersion (catalyst chemical industry Co., Ltd .: trade name Cataloid SI-3) was preliminarily added to 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 this solution composition was 5.3. This was left at room temperature for 3 days and then filtered through a 1 μm filter to prepare a composition 1-3.

(Production and Evaluation of Molded Article) Composition 1-1 was coated on a 3 mm-thick plate made of poly (bisphenol-A carbonate) resin (hereinafter abbreviated as PC) with a # 20 wire bar, and the mixture was cooled to 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. Then, the composition 1-2 was applied on the coating surface of the laminate with a # 50 wire bar, and allowed to stand at room temperature for 20 minutes, and then at 80 ° C. for 3 minutes.
Heat for 0 minutes. The coating film thickness was 15 μm. Furthermore,
The composition 1-3 was applied on 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 130 ° C. for 1 hour. The coating film thickness in this operation was 5 μm.

The obtained molded product was good in appearance and was transparent with no 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 a PC plate having a base material 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 (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 cracks 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 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 12% Δ haze, and a steel wool test result of 2. . [Comparative Example 3] Example 1 except that the composition 1-1 was not applied.
In exactly the same manner as described above, a PC plate molded body was obtained in which a cured layer of Composition 1-2 and a cured layer of Composition 1-3 were sequentially laminated in a thickness of 15 μm and 5 μm, respectively. The adhesiveness of the molded product is 0/10 in a cross-cut test.
It was 0. 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) 15 parts of the acrylic resin-B was added to the composition.
35 parts of c-butanol and methyl ethyl ketone (hereinafter ME
It was dissolved in a mixed solvent consisting of 40 parts (abbreviated as K) and filtered through a 1 μm filter to prepare a composition 2-1.

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

(Composition for the third layer) A 40% colloidal silica aqueous dispersion (catalyst chemical industry Co., Ltd .: trade name Cataloid SI-4) was previously added to 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 this solution composition was 5.2. This was left at room temperature for 2 days and then filtered with a 1 μm filter to prepare a composition 2-3.

(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 92%, and the appearance was transparent and good. Adhesiveness is 100/100 in a cross-cut test
The pencil hardness was 5H, the Taber abrasion test result was Δhaze value 1.7%, and the steel wool test result was 0 rating. 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 formed 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 formed on 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 30 minutes. The coating film thickness was 11 μm. Further, the composition 1-3 was applied on the surface of the laminated film with # 1.
Apply with a wire bar of No. 6 and leave at room temperature for 20 minutes, then
It was heat-cured at 0 ° C. for 4 hours. The coating film thickness in this operation was 4 μm. The adhesiveness of the obtained molded body is 100/1
The surface hardness was evaluated by pencil hardness of 7H, Δhaze value of 2.0% in Taber abrasion test, and steel wool test of 0. The molded body 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) The acrylic resin-D15 part was n-
Composition 4-1 was prepared by dissolving in a mixed solvent consisting of 35 parts of butanol and 40 parts of MIBK and filtering with a 1 μm filter.

(Composition for the second layer) 28.5 parts of methyltrimethoxysilane were 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 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 2 hours. Then, to the reaction solution was added a solution consisting of 6.0 parts of the acrylic resin-I and 42 parts of MIBK,
Further stirring was 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) 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 this solution composition was 5.2. This was left at room temperature for 3 days and then filtered through a 1 μm filter to prepare a composition 4-3.

(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 Δhaze value of 3.2%, and the result of the steel wool test was 0. Further, after the boiling water immersion test for 5 hours, the molded body did not show any change in appearance, adhesiveness and surface hardness.

Examples 5 to 6 PC laminates were produced in exactly the same manner as in Example 1 except that the acrylic resin -E or -F having a film thickness of 2 μm was used as the first layer. 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 4H, and the result of the Taber abrasion test was Δhaze value of 1.8%. Yes, the steel wool test result was a 0 rating. After the boiling water immersion test for 2 hours, the molded product did not show any change in appearance, adhesiveness and surface hardness.

Example 7 (Composition for First Layer) 15 parts of the acrylic resin C was dissolved in a mixed solvent consisting of 35 parts of 2-ethoxyethanol and 40 parts of MIBK and filtered through a filter of 1 μm to prepare composition 7-
1 was prepared.

(Composition for Second Layer) The composition 2-2 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, a composition 7-3 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 Δ haze value of 4.1%, and the result of the steel wool test was 0. Further, 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 Internal reference number FI Technical display location C09D 133/14 PFY C09D 133/14 PFY 143/04 PGL 143/04 PGL 183/04 PMN 183/04 PMN

Claims (8)

[Claims] 1. A surface of a plastic substrate is represented by the following formula (A): [In the formula, R ¹ is an alkyl group having 1 to 4 carbon atoms. ] A polymethacrylate-based acrylic resin (I) containing 50 mol% or more of the repeating unit represented by
A layer of the following formula (B): embedded image R ² _n —Si (OR ³ ) _4-n ……………… (B) [wherein R ² is an alkyl group having 1 to 4 carbon atoms, vinyl Group or an organic group having one or more groups selected from the group consisting of methacryloxy group, amino group, epoxy group and mercapto group, R ³ is an alkyl group having 1 to 4 carbon atoms, and n is 0 to 2 Is an integer. ] A (partial) hydrolyzate of alkoxysilane, a partial condensate thereof or a mixture thereof represented by 50 to 90% by weight (based on R ² _n SiO _{(4-n) / 2} ) based on the following formula (C ) And (D) [Wherein, X is a hydrogen atom or a methyl group, and R ⁴ ,
R ⁵ is independently an alkyl group having 1 to 4 carbon atoms, and m is an integer of 0 or 1. ] And the molar ratio (p / q) of such repeating units (C) and (D) is 99.99 / 0.01-.
Second layer formed by reaction thermosetting of a mixture or reaction product with 50 to 50% by weight of an acrylic resin (II) having an alkoxysilyl group of 50/50, and third layer formed by thermosetting an organopolysiloxane resin. A surface-protected plastic molded article, which is obtained by sequentially laminating the above from the first layer. 2. The first layer has the following formulas (A) and (G): [However, R ¹ is an alkyl group having 1 to 4 carbon atoms. R ¹⁰
Is an alkyl group having 1 to 4 carbon atoms, and l is an integer of 0 or 1. ] The repeating unit (A) and (G) has a molar ratio (r / s) of 99.99 / 0.01 to 50/50 and a polymethacrylate acrylic resin. The surface-protected plastic molded article according to claim 1. 3. The third layer has the following formula (E): R ⁶ —Si (OR ⁷ ) ₃ ---------- (E) [wherein R ⁶ is a carbon number. 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 ⁷ has 1 carbon atom ~ 4 alkyl groups. ] (Partially) hydrolyzate of trialkoxysilane, its partial condensate or a mixture thereof of 90 to 30% by weight (based on R ⁶ SiO _3/2 basis) and 10 to 70% by weight of colloidal silica. The surface-protected plastic molded product according to claim 1 or 2, which is composed of a layer obtained by thermosetting an organopolysiloxane resin. 4. The surface protected plastic molding according to claim 3, wherein at least 70% by weight of the trialkoxysilane used for forming the third layer is methyltrialkoxysilane. 5. The third layer is represented by the following formula (F) embedded image _{^{R 8 v -Si (OR 9)}} 4-v ---------- (F) [ provided that wherein R ⁸ Is a C1-C4 alkyl group, a vinyl group, or a C1-C3 substituted with one or more groups selected from the group of methacryloxy group, amino group, and glycidoxy group.
R ⁹ is an alkyl group having 1 to 4 carbon atoms, and v is an integer of 0 to 2. ] The surface-protected plastic according to claim 1 or 2, which comprises a layer obtained by thermosetting an organopolysiloxane resin comprising the hydrolysis of alkoxysilane, a partial condensate thereof, or a mixture thereof represented by Molded body. 6. The alkoxysilane represented by the formula (F) used in the third layer is mainly composed of 40 mol% or less of tetraalkoxysilane and 60 mol% or more of trialkoxysilane. 5. A plastic molded product whose surface is protected according to 5. 7. The surface-protected plastic molded product according to claim 1, wherein the plastic substrate is a polycarbonate resin. 8. A first layer is formed by applying the composition containing the acrylic resin (I) onto a plastic substrate and then heating the composition to form a first layer, and (partial) hydrolysis of an alkoxysilane on the first layer. Compound, a partial condensate thereof or a mixture thereof, and an acrylic resin having the alkoxysilyl group (I
The composition containing the mixture or reaction product with I) is applied, and then the second layer is formed by heating, the composition containing the organopolysiloxane resin is applied on the second layer, and then the second layer is formed by heating. A method for producing a plastic molded article whose surface is protected, which comprises forming three layers.