JPH08300569A - Surface protected plastic molding and method for producing the same - Google Patents

Abstract

PURPOSE: To improve resistance to wear, scratch hardness and the like by laminating successively a first layer composed of acrylic resin, a second layer obtained by reaction-thermosetting alkoxysilane, its hydrolyzate, its condensate or a mixture thereof with acrylic resin containing hydroxy, and a third layer obtained by thermosetting organopolysiloxane resin. CONSTITUTION: A composition containing acrylic resin is applied on a plastic base and heated thereon to form a first layer, and a composition containing alkoxysilane, its (partial) hydrolyzate, its partial condensate or a mixture of them and also containing a mixture of reaction product of alkoxysilane reacted with acrylic resin containing hydroxy is applied on the first layer. Then, a second layer is formed by heating, and a composition containing organopolysiloxane resin is applied on the second layer, and a third layer is formed by heating. As for acrylic resin constituting the first layer, polymethacrylate resin provided with the repeating unit represented by the formula of 50 molar % or more is used.

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 an organopolysiloxane cured product layer on the surface of a plastic substrate,
TECHNICAL FIELD The present invention relates to a plastic molding having a remarkably improved surface hardness and a method for producing the same.

[0002]

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

For the purpose of improving these drawbacks, many proposals have heretofore been made to improve the surface hardness by coating the surface of plastic with a silicone-based cured film. For example, a coating composition comprising a partial condensate of trihydroxysilane and colloidal silica (Japanese Patent Application Laid-Open No. 51-2)
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, the partial condensate or a mixture thereof and a second layer formed by reaction thermosetting with an acrylic resin having a hydroxyl group, and a third layer formed by thermosetting an organopolysiloxane resin, A plastic molded article having a protected surface, which is characterized by being laminated in order 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 a composition are applied, and then a second layer is formed by heating, and an organo 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 a polysiloxane resin and then forming a third layer by heating.

Examples of the acrylic resin constituting the first layer in the present invention include polymethacrylate resins having 50 mol% or more of the repeating unit represented by the following formula (A).

[0012]

[Chemical 7]

In the above formula (A), R ¹ is an alkyl group having 1 to 4 carbon atoms. Examples of such an alkyl group include a methyl group, an ethyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group and the like, and a methyl group and an ethyl group are particularly preferable.

The acrylic resin is preferably a homopolymer of polyalkylmethacrylate or a copolymer of 50 mol% or more of alkyl methacrylate and 50 mol% or less of other vinyl monomer. Other vinyl monomers are not particularly limited as long as they are copolymerizable, but in terms of durability such as adhesiveness or weather resistance,
Acrylic acid, methacrylic acid or their derivatives are preferred. Specifically, acrylic acid, methacrylic acid, acrylic acid amide, methacrylic acid amide, methyl acrylate,
Ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, 2-hydroxyethyl acrylate, 2
-Hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, N, N-diethylaminoethyl methacrylate, glycidyl methacrylate, and further 3-methacryloxypropyltrimethoxysilane, 3-
Examples thereof include (meth) acrylate vinyl monomers containing an alkoxysilyl group such as acryloxypropyltriethoxysilane and 3-methacryloxypropylmethyldimethoxysilane.

The above-mentioned copolymer of alkyl methacrylate and alkoxysilyl group-containing (meth) acrylate vinyl monomer has the following formulas (A) and (B):

[0016]

Embedded image

A copolymer composed of the repeating unit represented by the following formula can be preferably 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 is partially chemically bonded to the second layer. It is presumed that the adhesiveness of is further improved.

The acrylic resin may be composed of one type of repeating unit represented by the above formula (A) and may contain a combination of two or more types. Further, a ternary compound containing one or more combinations of repeating units represented by the above formula (A) and obtained by using one or more of the above vinyl monomers as a copolymerization component. It may be a copolymer of a system or more. The acrylic resin is
It may be a single kind or a mixture 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 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 reactively 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. Such an acrylic resin is a (meth) acrylate-based acrylic resin containing the 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 that forms the second 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 such vinyl monomers include styrene, vinyl acetate, acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, 2-ethylhexyl methacrylate and the like.

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, but cannot be generally specified, but it is 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 is 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 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 above 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, formic acid, acetic acid, propionic acid, butyric acid, lactic acid, tartaric acid, etc. are usually used as a curing catalyst.
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.

Further, 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.

Further, in order to further improve the weather resistance of the plastic substrate, the coating composition for the second layer may contain additives such as a light stabilizer and an ultraviolet absorber as described above for the second layer. 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 comprises
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 thickness of the second layer varies depending on the required scratch hardness, but it is usually 3 to 100 μm, preferably 5 to 100 μm.
The thickness is 80 μm, more preferably 8 to 50 μm. If the film thickness is less than 3 μm, the effect of improving scratch hardness cannot be obtained, and if it is more than 100 μm, cracks are likely to occur. The composite film constituting the second layer in the present invention has good adhesiveness with the above-mentioned first layer and a third layer described later,
By using such a composite film as the intermediate layer, it is possible to obtain a plastic molded product having excellent scratch resistance and durability during boiling water.

The third layer in the present invention is a thin film layer obtained by reaction thermosetting of an organopolysiloxane resin.
Here, the organopolysiloxane resin is a hydrolyzate of an alkoxysilane produced based on the sol-gel reaction,
And its condensate. Specifically, it is (partial) hydrolysis of alkoxysilane, a partial condensate thereof, or a mixture thereof, and also includes unreacted alkoxysilane.

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

[0070]

Embedded image After coating a coating composition comprising an alkoxysilane represented by R ⁶ _v —Si (OR ⁷ ) _4-v (F), a solvent, an acid and a small amount of a curing catalyst on the second layer, It is formed by heat curing. Such a coating composition also contains a (partial) hydrolyzate of alkoxysilane produced by sol-gel reaction of the alkoxysilane, a partial condensate thereof, or a mixture thereof.

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. 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 alkoxysilane include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, and tetra-n-butoxysilane. Above all,
Tetramethoxysilane and tetraethoxysilane are preferable from the viewpoint of economy and reactivity. Examples of the trialkoxysilane include methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, methyltrin-butoxysilane, ethyltrimethoxysilane,
Ethyltriethoxysilane, ethyltriisopropoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, methacryl Roxymethyltrimethoxysilane, methacryloxymethyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, etc. Can be mentioned. Of these, the wear resistance of the obtained cured film,
Methyltrialkoxysilane is preferable in terms of crack resistance, and methyltrimethoxysilane and methyltriethoxysilane are preferable in terms of economical efficiency 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.

In view of the performance of the coating film obtained, the alkoxysilane is 40 mol% or less of tetraalkoxysilane and 6
It is preferable to use a mixture mainly composed of 0 mol% or more of trialkoxysilane. By using such a mixture, the abrasion resistance of the coating film obtained 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 alkoxysilane and its partial condensate are usually 0.6 to 5 times equivalent, preferably 0.8 to 3.5 times, equivalent to 1 equivalent of alkoxy group in alkoxysilane. It can be obtained by adding an equivalent amount, more preferably 1 to 2 times equivalent amount of water, and reacting in the presence of an acid catalyst, without solvent or under dilution with a solvent. The alkoxysilane (partial) hydrolyzate thus obtained,
The sol-gel reaction liquid containing the partial condensate or a mixture thereof is usually aged and used. The aging period at this time depends on the type and concentration of the alkoxysilane used, the amount of water, the type and amount of the catalyst, and the type and amount of the diluting solvent, so it cannot be said unequivocally, but it is usually a few hours to several days. It is then used as a composition for coating.

As the solvent used in the coating composition,
It is necessary that the above-mentioned alkoxysilane, its (partial) hydrolyzate, its partial condensate or a mixture thereof is stably dissolved, and for that purpose, at least 20% by weight or more, preferably 50% by weight or more is alcohol. Is desirable. Examples of the alcohol include methanol, ethanol, isopropanol, n-butanol, sec-butanol, 2-ethoxyethanol, 4
-Methyl-2-pentanol, 2-butoxyethanol and the like are mentioned, alcohols having a low boiling point of 1 to 4 carbon atoms are preferable, and isopropanol is particularly preferable from the viewpoint of solubility, stability and coatability. 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 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.

Further, colloidal silica may be added to the above coating composition, if necessary.

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 above-mentioned alkoxysilane and colloidal silica is determined in view of the stability of the coating composition, the transparency of the obtained cured film, the abrasion resistance and the occurrence of cracks, etc., and is finally produced. Based on a cured film of organopolysiloxane containing colloidal silica, the former contains 90 to 30% by weight of (partial) hydrolyzate of the alkoxysilane, its partial condensate or these condensates (however,
Colloidal silica is used at 10 to 70% by weight, based on R ⁶ SiO _3/2 ). Further, these are contained in the composition in an amount of 10 to 50% by weight, preferably 15 to 30% by weight, as a substantial solid content.

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 tend 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.
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.
A layer, a layer obtained by reacting a sol-gel reaction product with an acrylic resin having a hydroxyl group and thermally curing it as a second layer, and a thin film layer obtained by thermally curing an organopolysiloxane resin as a third layer. By forming it, it becomes a durable molded article having high abrasion resistance, scratch hardness, and solvent resistance.

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) 2-Hydroxyethyl methacrylate (hereinafter abbreviated as HEMA) 13.1 parts, MMA 90.1
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)
I 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) 4-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) Adhesiveness: Vertically on the surface of the test piece with a knife,
Cuts are made at intervals of 1 mm horizontally to form 100 cross-cuts. Cellophane tape (product name: Cellophane, manufactured by Nichiban Co., Ltd.) was applied on the surface of the film, and then pulled at once in a direction of 90 degrees from the surface for peeling, 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: Using a Taber abrasion tester (manufactured by Toyo Seiki Co., Ltd.), wear wheels CS-10F, load 5
The surface of the test piece was abraded under the conditions of 00g and 500 cycles,
The difference in haze value before and after abrasion (Δ haze value) obtained from the following equation was evaluated. (JIS K6735 or ASTM D1044
According to)

[0103]

[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 strongly rubbed 1: Slightly scratched if strongly rubbed 2: Slightly scratched if strongly rubbed 3: Scratched if strongly rubbed 4: Even scratched weakly

(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 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: San Nopco Ltd.) 0.2
After adding 1 part, the composition 1-2 was prepared by filtering with a 1 μm filter.

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

(Production and Evaluation of Molded Article) Composition 1-1 was coated with a # 20 wire bar on a plate made of poly (bisphenol-A carbonate) resin (hereinafter abbreviated as PC) and having a thickness of 3 mm, 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 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 3.2%, and the steel wool test gave a rating of 0, indicating a very high surface hardness. When the laminate was immersed in boiling water for 5 hours, no change in appearance was observed and the adhesiveness was 100/100. In addition, the result of rubbing the surface after immersion with steel wool was 0, indicating excellent boiling water resistance.

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 having a thickness of 2.5 μm and Composition 1 were prepared in the same manner as in Example 1 except that the composition 1-2 was not applied onto a PC plate having a thickness of 3 mm. −
A cured layer of 3 (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, the Taber abrasion test has a Δ haze value of 1.8%, and the result of the steel wool test is 0.
The pencil hardness was F. In the molded product, slight whitening of the coating film was observed by immersion in boiling water for 2 hours,
The coating film was cracked by the immersion for 5 hours and the adhesiveness was lowered.

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 adhesiveness of the molded product was 100/100 in a cross-cut test, the pencil hardness was 3H, the Taber abrasion test was Δhaze value 10%, 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 added to the composition.
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 Product) In exactly the same manner as in Example 1, the first layer was 5 μm and the second layer was formed on the PC plate having a thickness of 3 mm.
A layer of 20 μm and a third layer of 5.5 μm were sequentially laminated. The obtained molded product had a total light transmittance of 91.4%, and the appearance was transparent and good. Adhesiveness is 100 / in cross-cut test
100, the pencil hardness was 5H, the Taber abrasion test result was Δ haze value 3.3%, and the steel wool test result was 0 rating. After boiling water immersion test for 5 hours,
The molded body did not show any 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 product had a coating film of the first layer 2.5 μm, the second layer 15 μm, and the third layer 5 μm. The adhesiveness of the molded body is 100/100,
It did not change at all after the 5 hour boiling water test. The surface hardness of the molded product was evaluated by pencil hardness 7H, Δhaze value 3.5% in Taber abrasion test, and steel wool test 0, and no change was observed even after immersion in boiling water for 5 hours.

On the other hand, the surface hardness of PMMA as the base material 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 was placed in an Erlenmeyer flask, and a solution of 3.0 parts of acetic acid and 12 parts of water was added under external cooling while stirring. After continuing stirring at room temperature for about 1 hour, 16 parts of isopropanol (hereinafter abbreviated as IPA) and 0.7 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) To 20 parts of tetraethoxysilane, 7 parts of a 0.01N hydrochloric acid aqueous solution was added with vigorous stirring under external cooling. Then, stirring was continued at room temperature for 3 hours, and then the mixture was allowed to stand at 10 ° C. for 24 hours or more for aging to prepare a sol-gel reaction solution of tetraethoxysilane. 28 parts of methyltrimethoxysilane was mixed with 3 parts of the sol-gel reaction solution, and 11.1 parts of 0.01 N hydrochloric acid aqueous solution was added thereto while vigorously stirring under external cooling. Then, after stirring at room temperature for 3 hours, 18.5 parts of IPA and 3.5 parts of a 10% sodium acetate acetic acid solution were added. The pH value of the system was 5.2. After standing at room temperature for 3 days, a composition 4-3 was prepared by filtering with a 1 μm filter.

(Manufacture and evaluation of molded body) PC having a thickness of 3 mm
The first layer 3 μm, the second layer 10 μm, and the third layer 5 μm were sequentially laminated on the plate by the dip coating method. As a result of evaluating the coating film performance of the obtained molded product, the adhesiveness was 100/100 in a cross-cut test, the pencil hardness was 3H, and the result of the Taber abrasion test was Δ haze value of 4.2%. The result of the steel wool test was 0.

[Examples 5 to 6] PC laminates were produced in exactly the same manner as in Example 4 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 performances of the two kinds of the obtained laminates, the adhesiveness was 100/100 in a cross-cut test, the pencil hardness was 3H, and the result of the Taber abrasion test was Δ haze value of 4. The result of the steel wool test was 0%. Two
After the boiling water immersion test for a time, the laminate did not show any change in appearance, adhesiveness and surface hardness.

[Example 7] (Composition for the first layer) The acrylic resin-C15 part 2
Composition 7 was dissolved in a mixed solvent consisting of 35 parts of ethoxyethanol and 40 parts of MIBK and filtered through a 1 μm filter.
-1 was prepared.

(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 the third layer) 20 parts of tetramethoxysilane was dissolved in 3 parts of IPA, and further 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 body) PC having a thickness of 3 mm
First layer 1.5μ on the plate using dip coating method
m, the second layer 15 μm, and the third layer 5 μm were sequentially laminated.
As a result of evaluating the coating 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 4.5%.
The result of the steel wool test was 0. Also,
The coating film did not change at all even after the boiling water test for 5 hours.

[Examples 8 to 10] A PC laminate was 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 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 Δ haze value of 3.2, respectively.
It was 3.1 and 3.1%, and the result of the steel wool test was 0. After the boiling water immersion test for 5 hours, the laminate did not show any change in appearance, adhesiveness and surface hardness.

Example 11 (1st layer composition) 15 parts of the acrylic resin B was sec.
-Dissolved in a mixed solvent consisting of 35 parts of butanol and 40 parts of MIBK, filtered through a 1 μm filter, and the composition 11-1
Was 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.

(Manufacture and Evaluation of Molded Product) In the same manner as in Example 1, the first layer 2 μm and the second layer were formed on the PC plate (thickness 3 mm).
A layer of 15 μm and a third layer of 5 μm were sequentially laminated. As a result of evaluating the coating 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 3.2%. 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 12 to 13] In the composition for the second layer,
"Cimel 303" (methyl ether type hexamethylol melamine resin) manufactured by Mitsui Cytec Co., Ltd. 3.0 parts and p-toluenesulfonic acid 0.1 part (Example 12),
Two types of PC laminates were carried out in exactly the same manner as in Example 11 except that 3.0 parts of "Cymel 370" (methyl ether type hexamethylol melamine resin) and 0.1 part of itaconic acid (Example 13) were further added and dissolved. A plate was made. As a result of evaluating the coating film performance of each of the obtained molded products, the adhesiveness was 100/100 in the cross-cut test, and the pencil hardness was 4 in all cases.
H, the result of the Taber abrasion test was 3.1 and 3.2%, respectively, and the result of the steel wool test was 0. After the boiling water immersion test for 5 hours, the molded product showed no change in appearance, adhesiveness and surface hardness.

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Claims (10)

[Claims] 1. A reaction thermosetting of a first layer made of an acrylic resin, an alkoxysilane, a (partial) hydrolyzate thereof, a partial condensate thereof, or a mixture thereof with an acrylic resin having a hydroxyl group on the surface of a plastic substrate. A surface-protected plastic molded article comprising a second layer thus obtained and a third layer obtained by thermosetting an organopolysiloxane resin, which are sequentially laminated. 2. The first layer has the following formula (A): (However, R ¹ is an alkyl group having 1 to 4 carbon atoms in the formula.) A layer made of a polymethacrylate acrylic resin containing 50 mol% or more of a repeating unit represented by the formula. A surface-protected plastic molding as described above. 3. The first layer has the following formulas (A) and (B): (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. ), And the molar ratio of the repeating units (A) and (B) (s /
The surface-protected plastic molded article according to claim 2, wherein t) is a polymethacrylate acrylic resin having 99.99 / 0.01 to 50/50. 4. 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 A surface-protected plastic molding according to any one of claims 1 to 3, which is a layer formed by thermosetting 10 to 10% by weight. 5. The acrylic resin of the second layer is represented by 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 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. 5. The surface-protected plastic molded product according to claim 4. 6. The third layer has the following formula (F): embedded image R ⁶ _v —Si (OR ⁷ ) _4-v (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. V is an integer of 0 to 2), which is a layer formed by heat-curing an organopolysiloxane resin composed of an alkoxysilane represented by the formula (1), a (partial) hydrolyzate thereof, a partial condensate thereof, or a mixture thereof. The surface-protected plastic molding according to any one of claims 1 to 5. 7. The alkoxysilane represented by the formula (D) used for forming the third layer is mainly composed of 40 mol% or less of tetraalkoxysilane and 60 mol% or more of trialkoxysilane. 7. The surface-protected plastic molding according to claim 6. 8. The surface-protected plastic molded product according to claim 1, wherein the plastic base material is a polycarbonate resin. 9. A first layer is formed by applying a composition containing an acrylic resin on a plastic substrate and then heating the same, and alkoxysilane, a (partial) hydrolyzate thereof, or a hydrolyzate thereof is formed on the first layer. A composition containing a partial condensate or a mixture thereof and an acrylic resin having a hydroxyl group is applied, and then a second layer is formed by heating, and a composition containing an organopolysiloxane resin is applied on the second layer. Then, a method for producing a plastic molded article whose surface is protected, characterized in that the third layer is formed by heating. 10. The surface-protected plastic molded product according to claim 9, wherein the organopolysiloxane resin comprises an alkoxysilane, a (partial) hydrolyzate thereof, a partial condensate thereof, or a mixture thereof. Manufacturing method.