JP3474964B2 - Plastic molded body with protected surface and method for producing the same - Google Patents

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, by sequentially laminating an acrylic resin layer, a cured product layer of an acrylic resin and an organopolysiloxane, and a cured product layer of colloidal silica-containing organopolysiloxane on the surface of a plastic substrate, a plastic whose surface hardness is remarkably improved. TECHNICAL FIELD The present invention relates to a molded body 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. 51-2)
736 and 55-94971),
These cured coatings impart excellent abrasion resistance to plastic substrates. However, these coating compositions tend to crack when thickly applied due to the shrinkage associated with the formation of a crosslinked network structure when they are heat-cured. Therefore, they are usually used in a thickness of about 6 μm or less. However, since the coating film thickness is thin, the influence of the surface hardness of the plastic base material 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 insufficient, and the surface is easily scratched by rubbing it 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 of improving the surface hardness of a plastic substrate, there is a method of applying a primer composition containing an acrylic resin having an alkoxysilyl group on the substrate and forming a film having a high surface hardness on the primer composition. It is disclosed (Japanese Patent Laid-Open No. 5-78615). However 2
Such a method having a layered structure has insufficient adhesion between the base material and the primer layer and has a problem in durability.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a plastic molding having a high surface hardness which is particularly excellent in wear resistance and scratch hardness, and excellent in durability, and a method for producing the same. It is in.

[0008]

The present inventor has conducted earnest research 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, according to the present invention, a first layer made of an acrylic resin, an alkoxysilane, and
The (partial) hydrolyzate, its partial condensate, or a mixture thereof, and a second layer formed by reacting and thermally curing an acrylic resin having a hydroxyl group, and an organopolysiloxane resin containing colloidal silica, which is thermally cured. A plastic molded article having a protected surface, characterized in that a third layer is sequentially laminated from the first layer.

In the present invention, a composition containing an acrylic resin is applied onto a plastic substrate and then heated to form a first layer, and alkoxysilane and its (partial) hydrolysis are formed on the first layer. Composition, a partial condensate thereof, or a mixture thereof and a mixture or a reaction product of an acrylic resin having a hydroxyl group, and then a composition is applied, and then a second layer is formed by heating, and a colloidal layer is formed on the second layer. A method for producing a plastic molded article having a protected surface, which comprises applying a composition containing an organopolysiloxane resin containing silica and then heating it to form a third layer.

[0011]

[0012]

[0013]

[0014]

Acrylic constituting the first layer in the present invention
The resin has the following formulas (A) and (B)

[0016]

[Chemical 8]

Alkyl polymers consisting of repeating units represented by
Tacrylate and alkoxysilyl group-containing (meth) acrylate
A copolymer with a rate vinyl monomer is used .

Here, in the above formulas (A) and (B),
R ¹ is an alkyl group having 1 to 4 carbon atoms such as a methyl group and an ethyl group. R ⁸ has 1 to 4 carbon atoms such as methyl group and ethyl group.
Is an alkyl group, and l is an integer of 0 or 1.

When the molar amounts of the repeating units represented by the above formulas (A) and (B) are s and t, respectively, the above copolymer has a molar ratio s / t 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 monomer having the alkoxysilyl group is more than 50 mol% of the total amount of the copolymerization components, the copolymer is apt to gel and lacks in storage stability, and similarly the adhesiveness after immersion in boiling water is deteriorated. I have something to do. The molar ratio s / t of such a copolymer is more preferably 99/1 to 60/40, and further preferably 97/3 to 70/30.

Further, the copolymer has R ^{1 of the} above formula (A).
Is more preferably a methyl group or an ethyl group, R ^{8 in the} above formula (B) is a methyl group, and 1 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, or partially chemically bonded to the second layer.
It is presumed that the adhesion with the layer will be further enhanced.

The upper SL acrylic resin may be a mixture of two or more even alone.

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 on a plastic substrate, a solution composition prepared by dissolving the acrylic resin in an inert volatile solvent is usually used. It is carried out by coating the surface of the material and then removing the solvent by drying 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, etc. esters, n-hexane, n-heptane, isooctane,
Hydrocarbons such as benzene, toluene, xylene, ethers such as diethyl ether, tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone And the like, acetonitrile, nitromethane and the like. These solvents are usually used alone, but two or more kinds may be mixed and used. Usually, the acrylic resin content in the solution composition is 1 to 40% by weight, preferably 3 to 30% by weight.

If desired, a light stabilizer and an ultraviolet absorber may be added to the solution composition in order to improve the weather resistance of the plastic molded product. Further, these agents can be used in combination.

Examples of the light stabilizer include bis (2,2,6,6-tetramethyl-4-piperidyl) carbonate and 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-
Hindered amines such as 4-piperidyl) phenyl 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,
Nickel complexes such as 5-di-tert-butyl-4-hydroxybenzylphosphoric acid monoethylate and nickel dibutyldithiocarbamate may be mentioned. These agents may be used alone or in combination of two or more, and usually 50 parts by weight or less, preferably 2 parts by weight, relative to 100 parts by weight of the acrylic resin.
It is used in an amount of 0 parts by weight or less.

Examples of the ultraviolet 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, αdimethylbenzyl) 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-tert-butyl-2'-hydroxyphenyl)-
Benzotriazoles such as 5-chlorobenzotriazole, 2- (3 ', 5'-di-tert-amyl-2'-hydroxyphenyl) benzotriazole, ethyl-2
-Cyano-3,3-diphenyl acrylate, 2-ethylhexyl-2-cyano-3,3-diphenyl acrylate and other cyanoacrylates, phenyl salicylate, p-tert-butylphenyl salicylate, p-
Salicylates such as octylphenyl salicylate, diethyl p-methoxybenzylidene malonate, bis (2
-Ethylhexyl) benzylidene malonate and the like. These agents may be used alone or in combination of two or more, and usually 100 parts by weight or less, preferably 5 parts by weight or less, relative to 100 parts by weight of the acrylic resin.
It is used in an amount of 0 parts by weight or less.

The above-mentioned solution composition containing an acrylic resin can be applied to a plastic substrate by a commonly used method such as dip coating, spray coating, flow coating, roller coating, bar coating or spin coating. It can be appropriately selected depending on the shape of the base material and the like.
The applied base material is usually dried at room temperature to a temperature not higher than the heat distortion temperature of the base material to remove the solvent, whereby the acrylic resin layer which is the first layer in the present invention is formed.

The thickness of the acrylic resin layer constituting the first layer is the same as that of the plastic substrate and the second layer in the present invention described later.
It may have a film thickness necessary for sufficiently adhering the layer and the subsequent layers, and for maintaining the necessary amount of the additive for improving the weather resistance, and usually 0.1 to 10 μm, preferably 1 to 5 μm
Is.

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 thin film layer obtained by thermosetting an alkoxysilane and an acrylic resin having a specific functional group.

The starting alkoxysilane used here is, for example, tetra-, tri- or dialkoxysilane represented by the following formula (C).

[0033]

Embedded image _{^{R 2 n -Si (OR 3)}} 4-n (C) wherein, 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 and a mercapto An organic group having one or more groups selected from the group consisting of 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 or cyclic, or may be branched, and these may be combined. It may have been done. The organic group may include a structure in which a part of carbon atoms constituting the organic group is replaced with a hetero atom such as an oxygen atom or a nitrogen atom. The organic group may have one or more groups selected from the group consisting of methacryloxy group, amino group, epoxy group and mercapto group as a substituent. 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 above-mentioned alkoxysilane is usually added in an amount of 0.5 to 10 relative to 1 equivalent of the alkoxy group in the alkoxysilane.
Double equivalent, preferably 1 to 5 equivalents, more preferably 1.
A sol-gel reaction solution is prepared by adding 5 to 3 equivalents of water and diluting with or without a solvent in the presence of an acid catalyst. Such a sol-gel reaction liquid, in addition to the raw material alkoxysilane,
By the usual sol-gel reaction, a part or all of the alkoxysilane is hydrolyzed (partial), a part or all of the hydrolyzate is condensed (partial) condensate, and the condensate is hydrolyzed. It usually contains a reaction product of condensation with a raw material alkoxysilane.

The sol-gel reaction liquid 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 that, it is used in the 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 and maleic acid. Organic acids such as 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 the diluent can be preferably used either before the hydrolysis reaction of the alkoxysilane or during the reaction, that is, during the aging.

The above-mentioned solvent is usually methanol, ethanol, isopropanol, n-butanol, sec.
An alcohol solvent such as butanol, 4-methyl-2-pentanol, 2-ethoxyethanol or 2-butoxyethanol is used. Two or more of these solvents 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 hydroxyl group-containing acrylic resin used to form the second layer in the present invention is, for example, a (meth) acrylate polymer containing 1 mol% or more of the repeating unit represented by the following formula (D). Can be mentioned.

[0043]

[Chemical 10]

Here, X is a hydrogen atom or a methyl group, and R ⁴ is an alkylene group having 2 to 5 carbon atoms such as an ethylene group. The acrylic resin is a (meth) acrylate-based acrylic resin containing a repeating unit represented by the above formula (D) in an amount of preferably 10 mol% or more, more preferably 20 mol% or more, still more preferably 30 mol% or more. The hardness of the cured film forming the layer is increased, which is desirable.

Further, the acrylic resin may be a (meth) acrylate polymer mainly composed of repeating units represented by the following formulas (D) and (E).

[0046]

[Chemical 11]

In the formula, X is a hydrogen atom or a methyl group, R ⁴ is an ethylene group, a propylene group or the like having 2 to 2 carbon atoms.
5 is an alkylene group, and R ⁵ is an alkyl group having 1 to 4 carbon atoms such as a methyl group and an ethyl group. Further, (meth) acrylate means methacrylate or acrylate.

The (meth) acrylate-based polymer is a homopolymer of a (meth) acrylate having a hydroxyl group or a copolymer of a hydroxyl group-containing (meth) acrylate and an alkyl methacrylate. A vinyl monomer component can be included. Examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate and 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-propyl methacrylate, 3-hydroxy-
2,2-dimethylpropyl methacrylate and the like can be mentioned. From the viewpoint of performance and economy of the resulting acrylic resin, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl methacrylate and 2-hydroxypropyl acrylate are particularly preferable. These compounds may be used alone or in combination of two or more.

As the alkyl methacrylate,
Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate,
Examples thereof include 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 is increased, but compatibility with the sol-gel reaction solution is lowered and microphase separation is likely to occur, resulting in whitening, which is preferable. Absent. These compounds may be used alone or in combination of two or more.

The (meth) acrylate polymer has a hydroxyl group represented by the formula (D) (meth).
Molar ratio (p / q) of repeating unit of acrylate and repeating unit of alkyl methacrylate represented by the above formula (E)
Is 1/99 to 100/0, preferably 5/95 to 10
It is a (co) polymer mainly composed of 0/0. When the repeating unit represented by the formula (D) is less than 1 mol%, that is, when the hydroxyl group is less than 1 mol%, sufficient scratch hardness cannot be obtained.

In addition, the acrylic resin is used in an amount of 30 with respect to the (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 not more than mol%, preferably not more than 15 mol%.

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 has a weight average molecular weight of 20,000 to 600,000, preferably 4
It is in the range of 10,000 to 400,000. Molecular weight is 2
When it is less than 10,000, the coating property and the flexibility of the obtained film are low and cracks are likely to occur, and when it is more than 600,000, the stability of the coating composition described later is lowered.

The above-mentioned acrylic resin is 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.

As such an inert solvent (polymerization solvent),
Hydrocarbons such as benzene, toluene, xylene, cyclohexane, hexane, acetone, methyl ethyl ketone,
Ketones such as methyl isobutyl ketone, ethers such as 1,2-dimethoxyethane, 1,3-dioxane and tetrahydrofuran, esters such as ethyl acetate, butyl acetate and ethoxyethyl acetate, methanol, ethanol, isopropanol, n-butanol Alcohols such as 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 second layer in the present invention comprises a sol-gel reaction liquid containing the above-mentioned alkoxysilane as a raw material, a (partial) hydrolyzate of the alkoxysilane, a partial condensate thereof or a mixture thereof, and the above-mentioned acryl having a hydroxyl group. It is formed by mixing a solution of a resin in a solvent, preferably leaving it at room temperature for several hours or more, and then using it as a coating composition for the second layer of the present invention. By leaving at room temperature, a transparent and uniform cured film without cracks can be obtained. The reason for this is that a sol-gel reaction product such as a (partial) hydrolyzate, a partial condensate thereof or a mixture thereof, which is formed by the reaction of the alkoxysilane during the standing period, and a hydroxyl group on the side chain of the acrylic resin are used. It is presumed that it partially reacts or is hydrogen-bonded to be micro-homogenized.

Regarding the mixing amount ratio of the raw material alkoxysilane and the acrylic resin, the former is 40 to 90% by weight, preferably (partial) hydrolyzate of the alkoxysilane, its partial condensate or a mixture thereof, preferably 50. ~ 80% by weight
(However, calculated as R ² _n SiO _{(4-n) / 2} ), the latter is 60
10 to 10% by weight, preferably 50 to 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 40% by weight, durability of the cured film, particularly water resistance is lowered, and scratch resistance of the cured film is insufficient.

As a solvent for dissolving the acrylic resin, after mixing with a sol-gel reaction liquid containing a sol-gel reaction product, both components of the acrylic resin and the sol-gel reaction liquid are dissolved,
Any material that does not impair the stability of the sol-gel reaction product may be used. Specifically, ethanol, isopropanol, n-
Alcohols such as butanol, sec-butanol, 2-ethoxyethanol, 4-methyl-2-pentanol, 2-butoxyethanol, diacetone alcohol, acetone, methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, methyl n-amyl ketone, Ketones such as 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 coating composition used to form the second layer of the present invention contains the one obtained by the sol-gel reaction and the acrylic resin having a specific functional group (hereinafter referred to as solid content). Is usually 3 to 50 when calculated as R ² _n SiO _{(4-n) / 2} obtained by the sol-gel reaction.
The solvent as the remaining amount may be derived from the solution containing the sol-gel reaction liquid and the acrylic resin, or may be newly added. The solvent may be selected from the above acrylic resin solvents. Also, at least 1 of the total amount of solvent
0% by weight or more, preferably 20% by weight or more can be selected from the above alcohol solvents.

In the above coating composition, 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, calculated as R ² _n SiO _{(4-n) / 2} ). It is preferable to add it in 0.1 to 15 parts by weight.

A melamine resin may be added to the coating composition for the purpose of improving durability such as water resistance and 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 can be preferably used. For example, "Cymel resin" manufactured by Mitsui Cytec Co., Ltd. and "Uban resin" manufactured by Mitsui Toatsu Chemicals, Inc. may be mentioned. The melamine resin can be used in an amount of 150 parts by weight or less, preferably 80 parts by weight or less, based on 100 parts by weight of the acrylic resin.

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.

In addition, the coating composition for the second layer contains the additives such as the light stabilizer and the ultraviolet absorber as described above for the purpose of further improving the weather resistance of the plastic substrate. It can be contained in an amount that does not impair the coating 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
It 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 base material and the like. The applied molded body is usually subjected to dry removal of the solvent at a temperature from room temperature to a temperature not higher than the heat distortion temperature of the substrate, and then 40 to 14
A composite of a silica sol, which is the second layer in the present invention, which is produced by using alkoxysilane as a starting material, and an acrylic resin having a hydroxyl group capable of reacting with this, which is the second layer in the present invention, by heat-curing at a temperature of 0 ° C. for 10 minutes to 4 hours. A film 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 8 to 50 μm. Improvement of thickness 8 [mu] m smaller than the scratch hardness can not be obtained, 50 [mu] m
If it is larger, cracks are likely to occur. Second in the present invention
The above-mentioned composite film constituting the layer has good adhesiveness to the above-mentioned first layer and a third layer to be described later. By using such a composite film as an intermediate layer, scratch resistance and boiling water It is possible to obtain a plastic molded article having excellent durability in, for example,

The third layer in the present invention is a thin film layer obtained by thermosetting an organopolysiloxane resin containing colloidal silica. Here, the organopolysiloxane resin containing colloidal silica is a hydrolyzate of trialkoxysilane produced based on the sol-gel reaction,
It mainly consists of a condensate and a reaction product of these with colloidal silica. Specific examples thereof include (partial) hydrolysis of trialkoxysilane, a partial condensate thereof, or a mixture thereof, and a (partial) condensate of colloidal silica and (partial) hydrolysis of the trialkoxysilane. Also included are reactive trialkoxysilanes and colloidal silica.

The third layer has, for example, the following formula (F)

[0071]

Embedded image Trialkoxysilane represented by R ⁶ —Si (OR ⁷ ) ₃ (F), colloidal silica,
It is formed by applying a coating composition comprising a solvent, an acid and a small amount of a curing catalyst on the second layer and then curing the composition by heating. Such a coating composition also contains a (partial) hydrolyzate of trialkoxysilane, a partial condensate thereof, or a mixture thereof, in which trialkoxysilane is formed by a sol-gel reaction.

In the above formula (F), R ⁶ is a carbon number substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a vinyl group, a methacryloxy group, an amino group and a glycidoxy group. It is an alkyl group having 1 to 3 and R ⁷ is an alkyl group having 1 to 4 carbon atoms.

Examples of the trialkoxysilane include methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane and methyltrin-n-.
Butoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane,
Propyltrimethoxysilane, butyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane,
Methacryloxymethyltrimethoxysilane, methacryloxymethyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane,
3-glycidoxy propyl triethoxysilane etc. are mentioned.

Further, in terms of wear resistance of the obtained cured film,
At least 70% by weight of the trialkoxysilane is methyltrialkoxysilane, and the total amount of the trialkoxysilane is preferably methyltrialkoxysilane, and among them, methyltrimethoxysilane and methyltriethoxysilane are preferable. 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
-100 nm, preferably 10 to 30 nm, and usually 10 to 50% by weight of an aqueous dispersion or a lower aliphatic alcohol dispersion, preferably an aqueous dispersion is 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 trialkoxysilane and colloidal silica is determined by the stability of the coating composition, the transparency of the cured film obtained, the abrasion resistance and the presence or absence of cracks. 90 to 30% by weight based on the cured film of the organopolysiloxane containing colloidal silica, including the (partial) hydrolyzate of the trialkoxysilane, its partial condensate or these condensates.
Colloidal silica is used in an amount of 10 to 70% by weight based on (provided that R ⁶ SiO _3/2 is used). Further, these are contained in the composition in an amount of 10 to 10 as a substantial solid content.
It is contained in the range of 50% by weight, preferably 15 to 30% by weight.

The (partial) hydrolyzate and partial condensate of trialkoxysilane in the coating composition are formed in situ by adding an aqueous colloidal silica dispersion to trialkoxysilane. When Si—OH is generated by hydrolysis in an acidic aqueous medium, hydroxyl groups are condensed to form a Si—O—Si bond. However, the condensation is partial rather than complete and the condensate contains significant amounts of Si.
It retains the -OH groups and is thereby dissolved in a water / alcohol solvent. The coating composition usually becomes a stable composition by further aging for several hours to several days.

The colloidal silica aqueous dispersion generally contains a sufficient amount of water necessary for trialkoxysilane hydrolysis and partial condensation reaction, but water may be further added if necessary. Alkoxy group of trialkoxysilane 1
The equivalent is usually 1 to 10 times equivalent, preferably 1.5.
-7 times equivalent, and more preferably 2-4 times equivalent of water is used.

The solvent used in the coating composition is
It is necessary that the partial condensate of the above trialkoxysilane is stably dissolved, and for that purpose, it is desirable that at least 20% by weight, and preferably 50% by weight or more, be alcohol. Examples of such alcohols include methanol, ethanol, isopropanol, n-butanol, sec-butanol, 2-ethoxyethanol, 4-methyl-2-pentanol, 2-butoxyethanol and the like, which have a low carbon number of 1 to 4. Alcohols having a boiling point are preferable, and isopropanol is particularly preferable in terms of solubility, stability and coatability. The solvent also includes a lower alcohol that accompanies the hydrolysis of the trialkoxysilane, water as a dispersion medium of colloidal silica, or a lower alcohol that does not participate in the hydrolysis reaction. 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 coating composition has a pH of 3.0 to 6.0, preferably 4.0 by adding a suitable acid.
It is necessary to adjust it to 5.5. As a result, hydrolysis and partial condensation reaction of the trialkoxysilane can be promoted, gelation at room temperature can be prevented, and storage stability can be increased. Such an acid may be added to the trialkoxysilane or colloidal silica dispersion in advance, or both may be added after mixing. Further, the addition can be performed once or divided into two or more times. Examples of the acid used 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,
Organic acids such as butyric acid, oxalic acid, succinic acid, maleic acid, lactic acid, and p-toluenesulfonic acid are mentioned, and acetic acid is particularly preferable from the viewpoint of storage stability. 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 coating composition.

Further, a catalyst for promoting heat curing is added to the coating composition. As the catalyst, the above-mentioned second layer curing catalyst is used. Particularly, sodium acetate, potassium acetate, benzyltrimethylammonium acetate, and tetramethylammonium acetate are preferable. The addition amount varies depending on the curing conditions, but it is 0.
It is 01 to 5% by weight, preferably 0.05 to 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 is applied onto the second layer. As a coating method, a commonly used method such as dip coating, spray coating, flow coating, roller coating, bar coating or spin coating is used, and it can be appropriately selected depending on the shape of the substrate. 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 usually 50-1
Heat cure at a temperature of 50 ° C for 10 minutes to 4 hours, silanol remaining in this process is condensed and silsesquioxane R
⁴ The thin film of the third layer, which has changed to the SiO _3/2 structure and is excellent in wear resistance and solvent resistance, is firmly bonded through the first layer and the second layer, and the plastic molded product of the present invention is obtained. .

A part or all of the above-mentioned 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 2 to 10 μm, preferably 3 to 8 μm, more preferably 4 to 7 μm. If the film thickness is smaller than 2 μm, sufficient abrasion resistance cannot be obtained, and if it is larger than 10 μm, cracks are likely to occur in the thin film.

A known leveling agent can be used for the purpose of improving the coatability of the composition for the first layer and the second or third layer of the present invention and the smoothness of the resulting coating film. . The addition amount is usually 0.01 to 2% by weight with respect to the composition.
Is the range.

The plastic substrate used in the present invention may be transparent or opaque, and examples of the substrate include a polycarbonate resin such as poly (bisphenol-A carbonate), an acrylic resin 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.

[0087]

The surface-protected plastic molded article of the present invention thus obtained is composed of the first acrylic resin.
Layer, a layer obtained by reacting a sol-gel reaction product with an acrylic resin having a hydroxyl group and thermally cured is a second layer, and a thin film layer obtained by thermally curing an organopolysiloxane resin containing colloidal silica is a third layer. By forming the three-layer structure, a molded article having high wear resistance, scratch hardness, and solvent resistance with durability can be obtained.

The surface-protected plastic molded product of the present invention thus obtained has excellent transparency, durability, high abrasion resistance, scratch hardness, and solvent resistance. , Windows of automobiles, headlight lenses, etc., windows of construction machinery, optical lenses, mirrors, glasses, goggles, sound insulation walls of roads, mirrors, windows of buildings, houses, garages, greenhouses, roofs, etc. Etc., can be preferably used for nameplates and the like.

[0089]

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

Reference Examples 1 to 12 (Synthesis Examples of Acrylic Resins A to L) 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) MMA 90 parts, ethyl acrylate (hereinafter abbreviated as EA) 6.9 parts, acrylic acid (hereinafter abbreviated as AA) 1.5 parts, AIBN 0.14 parts and toluene 20
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) 13.1 part of 2-hydroxyethyl methacrylate (hereinafter abbreviated as HEMA), MMA90.1
Parts, azobisisobutyronitrile (hereinafter abbreviated as AIBN) 0.16 parts and 200 parts of 1,2-dimethoxyethane were used for polymerization in the same manner as in the above a) and the weight of n-hexane and isopropyl alcohol. Purified by reprecipitation in a mixed solvent of 3/1 ratio, HEMA / MMA composition ratio 10/9
95 parts of 0 (molar ratio) copolymer (acrylic resin-G)
Got The weight average molecular weight of the polymer was 100,000 as measured by GPC.

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

F) 39.0 parts of HEMA, 80.1 parts of ethyl methacrylate (hereinafter abbreviated as EMA), AIBN0.
108 parts of a copolymer (acrylic resin-J) 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.

G) 2-Hydroxypropyl methacrylate (hereinafter abbreviated as HPMA) 43.2 parts, MMA 70.1
HP, in the same manner as in e) above, except that 0.16 parts of AIBN and 220 parts of 1,2-dimethoxyethane were used.
108 parts of copolymer (acrylic resin-K) having a MA / MMA composition ratio of 30/70 (molar ratio) was obtained. The weight average molecular weight of the polymer was 150,000.

H) 2-hydroxyethyl acrylate (hereinafter abbreviated as HEA) 23.2 parts, MMA 80.1 parts,
AIBN 0.16 parts and 1,2-dimethoxyethane 20
In the same manner as in the above a) except that 0 part was used, HEA /
95 parts of a copolymer (acrylic resin-L) having an MMA composition ratio of 20/80 (molar ratio) was 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) Adhesion: Using a knife, make cuts on the surface of the test piece at intervals of 1 mm in the vertical and horizontal directions to form 100 cross-cuts. 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 means complete adhesion and 0/100 means complete peeling. (Compliant with JIS K5400) (2) Scratch hardness: The pencil of the operator is 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 the hardest pencil that is not damaged. (Based on JIS K5400) (3) Abrasion resistance: Taber abrasion tester (Toyo Seiki Co., Ltd.)
Made wheel), wear wheel CS-10F, load 500 g, 5
The surface of the test piece was abraded under the condition of 00 cycles, and the difference in haze value before and after abrasion (Δ haze value) obtained from the following equation was evaluated.
(Based on JIS K6735 or ASTM D1044)

[0101]

[Equation 1]

(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 strongly rubbed 1: Slightly scratched if strongly rubbed 2: Slightly scratched if strongly rubbed 3: Scratched if strongly rubbed 4: Scratched even if weakly rubbed (5) Boiling water resistance: Test piece in tap water The appearance change, adhesiveness and scratch resistance of the coating film after boiling for 2 hours or 5 hours were evaluated.

Example 1 (Composition for First Layer) 10 parts of the acrylic resin-A was se
Dissolve in a mixed solvent of 45 parts of c-butanol and 45 parts of methyl isobutyl ketone (hereinafter abbreviated as MIBK), and
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 24 hours. Then, a solution of 5.0 parts of the acrylic resin-G 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. 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 composition 1-2.
Was prepared.

(Composition for the third layer) 30% of methyltrimethoxysilane was preliminarily mixed with 30% aqueous dispersion of colloidal silica (manufactured by Catalysts & Chemicals Co., Ltd .: trade name Cataloid SI-3).
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 0.4 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 20 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 article 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 1.7%, and the steel wool test had an evaluation of 0, indicating that the surface hardness was very high. 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.

On the other hand, in the case of the PC plate of the 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 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. The PC board laminated body laminated | stacked one by one was obtained. The adhesion of the laminate was 100/100 in a cross cut test, the pencil hardness was 3H, the Taber abrasion test was Δhaze value 11%, and the result of the steel wool test was 2. .

Comparative Example 3 A cured layer of Composition 1-2 and a cured layer of Composition 1-3 were successively 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) 15 parts of the acrylic resin-A was mixed with se.
The composition 2-1 was dissolved in a mixed solvent consisting of 35 parts of c-butanol and 40 parts of MIBK and filtered through a 1 μm filter.
Was prepared.

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

(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 91.4%, 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 The same coating as in Example 1 was applied onto a polymethylmethacrylate (abbreviated as PMMA) resin plate having a thickness of 2 mm. The obtained molded body has the first layer 2.
It had a coating film of 5 μm, second layer 15 μm, and third layer 5 μm. The adhesiveness of the molded product was 100/100, which was not changed even after the boiling water test for 5 hours. The surface hardness of the molded product is 7H in pencil hardness, and Δhaze value is 1. in the Taber abrasion test.
The evaluation was 9% and the steel wool test was 0, and no change was observed 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 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 0.7 part of benzyltrimethylammonium acetate were added to the reaction solution. Further, stirring was continued at room temperature for about 24 hours. Next, 7.0 parts of the acrylic resin-H and MIBK were added to the reaction solution.
A solution consisting of 42 parts was added and stirring was continued for 4 hours. The polysiloxane-based paint additive Perenol S4 was added to 0.2%.
After adding 2 parts, the composition was filtered with a 1 μm filter to obtain composition 4-2.
Was prepared.

(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. Then, after continuing stirring at room temperature for 24 hours, 38 parts of IPA and 0.8 part of benzyltrimethylammonium acetate were added. The pH value of the system was 5.2. After standing at room temperature for 2 days, it was filtered through a 1 μm filter to prepare a composition 4-3.

(Manufacture and Evaluation of Molded Article) The first layer 3 μm and the second layer 1 were formed on a PC plate having a thickness of 3 mm by the dip coating method.
0 μm and a third layer 5 μm were sequentially laminated. As a result of evaluating the coating film performance of the obtained molded product, the adhesiveness was 1 in a cross-cut test.
The result was 00/100, the pencil hardness was 3H, the Taber abrasion test result was Δhaze value 1.6%, and the steel wool test result was 0 evaluation.

[0123]

Example 5 (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 to prepare 1
Composition 7-1 was prepared by filtering with a μm filter.

(Composition for Second Layer) The acrylic resin-G
A composition 7-2 was prepared in exactly the same manner as in Example 1 except that 5.0 parts of the acrylic resin-I was used instead of.

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

(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 a dip coating method.
The second layer 15 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 4H.
The result of the Taber abrasion test was Δ haze value of 1.7%, and the result of the steel wool test was 0. Further, the coating film did not change at all even after the boiling water test for 5 hours.

[Examples 6 to 8 ] PC laminates were produced in exactly the same manner as in Example 1 except that the acrylic resins -J, -K and -L were used for the second layer. As a result of evaluating the coating film performance of the obtained molded body,
In both cases, the adhesiveness is 100/100 in the cross-cut test,
The pencil hardness was 4H, the results of the Taber abrasion test were Δhaze values of 1.7, 1.6, and 1.6%, respectively, 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 9 (Composition for First Layer) 15 parts of the acrylic resin B was dissolved in a mixed solvent consisting of 35 parts of sec-butanol and 40 parts of MIBK and filtered through a 1 μm filter to obtain composition 11-1. Prepared.

(Composition for the second layer) 24.4 parts of methyltrimethoxysilane was placed in an Erlenmeyer flask, and a solution of 2.5 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 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.

(Production 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 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 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 10 to 11 ] 3.0 parts of "Cymel 303" (methyl ether type hexamethylol melamine resin) manufactured by Mitsui Cytec Co., Ltd. and 0.1 part of p-toluenesulfonic acid were added to the composition for the second layer. Parts (Example 10 ), 3.0 parts of "Cymel 370" (methyl ether type hexamethylol melamine resin) and 0.1 parts of itaconic acid (Example 11 ) were added and dissolved.
Two types of PC laminates were produced in exactly the same manner as in Example 9 . As a result of evaluating the coating 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 result of the Taber abrasion test was Δhaze value of 1.5 each. , 1.6%, and the steel wool test result was evaluated as 0. After the boiling water immersion test for 5 hours, the molded product showed no change in appearance, adhesiveness and surface hardness.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-3-168227 (JP, A) JP-A-7-108218 (JP, A) JP-A-6-166847 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B32B 1/00-35/00 B05D 1/00-7/26

Claims (8)

(57) [Claims] 1. The following formula (A) is provided on the surface of a plastic substrate.
And (B) ## STR2 ## (However, in the formula, R ¹ is an alkyl group having 1 to 4 carbon atoms.
R ⁸ is an alkyl group having 1 to 4 carbon atoms, and l is 0 or 1
Is an integer. ) Consists of repeating units
, The molar ratio of the repeating units (A) and (B) (s /
Polymer whose t) is 99.99 / 0.01 to 50/50
First layer of methacrylate-based acrylic resin, alkoxysilane, its (partial) hydrolyzate, Ri Na cured reaction heat an acrylic resin having a partial condensate thereof or a mixture thereof to hydroxyl groups, and thickness Is 8-50μ
m Der Ru second layer, plastic molding the organopolysiloxane resin containing colloidal silica was protecting the surface, characterized in that successively laminated a third layer comprising a thermoset. 2. The second layer has the following formula (C): embedded image R ² _n —Si (OR ³ ) _4-n (C) (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 0 to 0. Which is an integer of 2), its (partial) hydrolyzate, its partial condensate or a mixture thereof 40 to 90% by weight (R ² _n SiO ²
₍ Weight basis by conversion to _{(4-n) / 2} ) and the following formula (D) (However, in the formula, X is a hydrogen atom or a methyl group, and R ⁴ is an alkylene group having 2 to 5 carbon atoms.) A (meth) acrylate-based acrylic resin 60 containing 1 mol% or more of the repeating unit represented by plastic molding, which is protecting the surface of claim 1, wherein the a 10% by weight a layer formed by thermally curing. 3. The acrylic resin of the second layer has the following formulas (D) and (E): (However, 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 1 to 1 carbon atoms.
4 is an alkyl group. ) Is a (meth) acrylate-based acrylic resin mainly composed of the repeating unit represented by the formula (1) and having a molar ratio (p / q) of the repeating units (D) and (E) of 1/99 to 100/0. The surface-protected plastic molded article according to claim 2 . 4. The third layer has the following formula (F): embedded image R ⁶ —Si (OR ⁷ ) ₃ (F) (wherein R ⁶ 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 ⁷ is an alkyl group having 1 to 4 carbon atoms.). Trialkoxysilane shown, its (partial) hydrolyzate, its partial condensate or a mixture thereof 90 to 30% by weight (weight basis based on R6SiO3 / 2 conversion) and colloidal silica 10 to 70% by weight.
Plastic moldings protected surface according to any one of claims 1 to 3, the organopolysiloxane resin, characterized in that a layer formed by thermally curing consisting of. 5. The surface-protected plastic molding according to claim 4 , wherein at least 70% by weight of the trialkoxysilane used for forming the third layer is methyltrialkoxysilane. 6. A plastic molded body that is protecting the surface according to any one of claims 1 to 5, the plastic substrate is characterized in that it is a polycarbonate resin. 7. A compound represented by the following formula (A) on a plastic substrate:
(B) [of 13] (However, in the formula, R ¹ is an alkyl group having 1 to 4 carbon atoms.
R ⁸ is an alkyl group having 1 to 4 carbon atoms, and l is 0 or 1
Is an integer. ) Consists of repeating units
, The molar ratio of the repeating units (A) and (B) (s /
Polymer whose t) is 99.99 / 0.01 to 50/50
Applying a composition containing a tacrylate-based acrylic resin,
Then, the first layer is formed by heating, and a composition containing an alkoxysilane, a (partial) hydrolyzate thereof, a partial condensate thereof or a mixture thereof and an acrylic resin having a hydroxyl group is formed on the first layer. A second layer is formed by coating and then heating, and a composition containing an organopolysiloxane resin containing colloidal silica is coated on the second layer, and then the third layer is formed by heating. A method for producing a plastic molded body whose surface is protected. 8. An organopolysiloxane resin containing colloidal silica is represented by the following formula (F) : embedded image R ⁶ —Si (OR ⁷ ) ₃ (F) (wherein R ⁶ has 1 to 4 carbon atoms ). Alkyl group of vinyl
Group, or methacryloxy group, amino group and glycidoxy group
Charcoal substituted with one or more groups selected from the group consisting of
It is an alkyl group having a prime number of 1 to 3, and R ⁷ has a carbon number of 1 to 4.
It is an alkyl group . From 90 to 30% by weight (based on the weight of R ⁶ SiO _3/2 ) of colloidal silica and 10 to 70% by weight of trialkoxysilane, its (partial) hydrolyzate, its partial condensate or a mixture thereof. The method for producing a plastic molded article having a protected surface according to claim 7, wherein: