JPH1095937A - Coating agent and resin molded product having cured coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a coating agent containing a (meth)acrylate monomer and surface-treated metal oxide particles, capable of imparting high surface hardness to resin molded products and capable of being converted into a non-solvent type coating agent. SOLUTION: This coating agent contains (A) a (meth)acrylate monomer or its partial condensation product and (B) metal oxide particles whose surface are treated with the hydrolysate of a silane compound of the formula [R<1> is a monovalent hydrocarbon or a fluorinated alkyl; R<2> is a divalent 1-10C (substituted) hydrocarbon; R<3> , R<4> are each H, methyl; X is a hydrolyzable group; Y is a divalent or larger (substituted) hydrocarbon, etc.; (a) is an integer of 1-3; (b) is an integer of 1-5]. The particles are preferably colloidal silica. The components A and B are preferably compounded in an A/B weight ratio of 100/(5-2,000). The coating agent can thereby give resin molded products high in surface hardness and especially good in transparency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a resin molded article having a coating agent and a coating film having high hardness.

[0002]

2. Description of the Related Art Conventionally, as an alternative to a transparent glass plate,
It is widely known that a transparent resin material having high resistance to destruction is used. However, the transparent resin material has a serious disadvantage that the surface is softer than glass and is easily damaged by surface wear and scratching.

There have been many attempts to improve the abrasion resistance of this resin material.
As described in JP-A-3-102936, JP-A-53-104638, JP-A-54-97633, etc., a compound having a plurality of (meth) acryloyloxy groups in a molecule is molded into a resin. This is a method of obtaining a resin molded product having excellent abrasion resistance by applying the composition on a substrate and curing the same with heat or active energy rays such as ultraviolet rays. However, such a method has the advantage that the curing liquid is also relatively inexpensive and excellent in productivity, but since the cured coating film is an organic substance,
There is a limit in obtaining abrasion resistance of a resin molded product having a cured coating film.

On the other hand, in order to impart a higher surface hardness to a resin molded product, as described in, for example, JP-A-48-26822 and JP-A-59-64671, an alkoxysilane compound is used. A method in which the composition is applied to a molded article and cured by heat, or disclosed in JP-A-56-10696.
As described in, for example, Japanese Patent Application Laid-Open No. 9-205, a method is known in which a mixture of colloidal silica and a resin is applied to a resin molded product and cured by heat.

However, these methods also require a drying step because of the use of a solvent, and require curing by heat, which consumes a large amount of energy and requires a long time for curing, which is industrially disadvantageous. Further, the fact that the solvent must be volatilized in the curing step of the coating film is very undesirable from the viewpoint of protection of the global environment.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin molded product having a coating agent capable of imparting a high surface hardness to a resin molded product and having no solvent and a cured coating film having a high surface hardness. To provide.

[0007]

Means for Solving the Problems The present invention relates to a method for preparing a fine particle surface comprising a (meth) acrylate monomer (a) or a partial condensate thereof and a hydrolyzate of a silane compound represented by the following general formula [1]: Wherein the coating agent comprises treated metal oxide fine particles (b).

[0008]

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The present invention also provides a resin molded product having a cured coating film obtained by radical polymerization of a coating layer obtained by applying the coating agent on the surface of the resin molded product.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below.
In the present invention, (meth) acryloyloxy group means acryloyloxy group and / or methacryloyloxy group, (meth) acrylic acid means acrylic acid and / or methacrylic acid, and (meth) acrylate means acrylate and / or methacrylate.

In the coating agent of the present invention, (meth) acrylate monomer (a) which is one of the constituent components
Is a component for imparting the hardness of the cured coating film, and may be a partial condensate thereof. The (meth) acrylate monomer (a) is mainly composed of a polyfunctional (meth) acrylate monomer (a ₁ ) having at least two (meth) acryloyloxy groups in the molecule. In the (meth) acrylate monomer (a ₁ ), the residue for bonding each (meth) acryloyloxy group is carbon hydrogen or a derivative thereof, and an ether bond, a thioether bond,
It may contain an ester bond, an amide bond, a urethane bond and the like.

The polyfunctional (meth) acrylate monomer (a ₁ ) includes, for example, polyhydric alcohol and (meth)
Esterified product obtained from acrylic acid or its derivative, or polyhydric alcohol, polycarboxylic acid and (meth)
A linear ester obtained from acrylic acid or a derivative thereof is exemplified.

Specific examples of an ester obtained from a polyhydric alcohol and (meth) acrylic acid or a derivative thereof include diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, and tetraethylene glycol di (meth) acrylate. Such as polyethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 3-acryloyloxy -2-hydroxypropyl (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, pentaglycerol tri (meth) acrylate, pentaerythritol tri (meth) Acrylate, pentaerythritol tetra (meth) acrylate, glycerin tri (meth) acrylate, a compound represented by the following general formula [3],

[0014]

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For example, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tripentaerythritol tetra (meth) acrylate, tripentaerythritol Examples include pentaerythritol penta (meth) acrylate, tripentaerythritol hexa (meth) acrylate, and tripentaerythritol hepta (meth) acrylate.

The linear ester obtained from a polyhydric alcohol, a polycarboxylic acid and (meth) acrylic acid or a derivative thereof includes a hydroxyl group of the polyhydric alcohol, a polycarboxylic acid and (meth) acrylic acid or A saturated or unsaturated polyester poly (meth) acrylate obtained by subjecting a mixture in which both carboxyl groups of the derivative and the carboxyl group have an equal amount to a condensation reaction.

Specific examples of preferred combinations include trimethylolethane / malonic acid / (meth) acrylic acid, trimethylolpropane / malonic acid / (meth) acrylic acid, glycerin / malonic acid / (meth) acrylic acid, Erythritol / malonic acid / (meth) acrylic acid, trimethylolethane / succinic acid / (meth) acrylic acid, trimethylolpropane / succinic acid / (meth)
Acrylic acid, glycerin / succinic acid / (meth) acrylic acid, pentaerythritol / succinic acid / (meth) acrylic acid,

Trimethylolethane / adipic acid / (meth) acrylic acid, trimethylolpropane / adipic acid / (meth) acrylic acid, glycerin / adipic acid / (meth) acrylic acid, pentaerythritol / adipic acid /
(Meth) acrylic acid, trimethylolethane / glutaric acid / (meth) acrylic acid, trimethylolpropane / glutaric acid / (meth) acrylic acid, glycerin / glutaric acid / (meth) acrylic acid, pentaerythritol / glutaric acid / ( (Meth) acrylic acid, trimethylolethane /
Sebacic acid / (meth) acrylic acid, trimethylolpropane / sebacic acid / (meth) acrylic acid, glycerin /
Sebacic acid / (meth) acrylic acid, pentaerythritol / sebacic acid / (meth) acrylic acid,

Trimethylolethane / fumaric acid / (meth) acrylic acid, trimethylolpropane / fumaric acid /
(Meth) acrylic acid, glycerin / fumaric acid / (meth)
Acrylic acid, pentaerythritol / fumaric acid / (meth) acrylic acid, trimethylolethane / itaconic acid /
(Meth) acrylic acid, trimethylolpropane / itaconic acid / (meth) acrylic acid, glycerin / itaconic acid /
(Meth) acrylic acid, pentaerythritol / itaconic acid / (meth) acrylic acid, trimethylolethane / maleic anhydride / (meth) acrylic acid, trimethylolpropane / maleic anhydride / (meth) acrylic acid, glycerin / maleic anhydride Acid / (meth) acrylic acid, pentaerythritol / maleic anhydride / (meth) acrylic acid, and the like.

Other examples of the polyfunctional (meth) acrylate monomer (a ₁ ) include trimethylolpropane toluylene diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, xylene diisocyanate, and 4,4'- An isocyanate represented by the following general formula [4] obtained by reacting a diisocyanate such as methylene bis (cyclohexyl isocyanate), isophorone diisocyanate, or isophorone diisocyanate with a diol is added with an active hydrogen group-containing (meth) acrylate per isocyanate molecule. Urethane (meth) acrylate or tris (2-hydroxyethyl) isocyanuric acid di (meth) obtained by reacting 3 mol or more by a conventional method.
Poly [(meth) acryloyloxyethyl] isocyanurate such as acrylate and tri (meth) acrylate, and the like, and further known epoxy poly (meth)
Acrylate, urethane poly (meth) acrylate and the like can be mentioned.

[0021]

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As the (meth) acrylate having an active hydrogen used in the reaction with the isocyanate, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-methoxypropyl ( (Meth) acrylate, N-methylol (meth) acrylamide, N-hydroxy (meth) acrylamide, 1,2,3-propanetriol-1,3-di (meth) acrylate, 3- (meth) acryloyloxy-2-hydroxy Propyl (meth) acrylate and the like.

The (meth) acrylate monomer (a) includes:
Polyfunctional (meth) acrylate monomer having at least two (meth) acryloyloxy groups in the molecule (a ₁ )
Besides, viscosity reduction of coating agent due to dilution effect,
From the viewpoint of improving the adhesion between the cured coating layer and the substrate and imparting flexibility to the cured coating film, a monofunctional (meth) acrylate monomer copolymerizable with the polyfunctional (meth) acrylate monomer (a ₁ ) The monomer (a ₂ ) may be contained as a mixture.

Examples of the copolymerizable monofunctional (meth) acrylate monomer (a ₂ ) include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, i-butyl (meth) acrylate ,
t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, tridecyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (Meth) acrylate, glycidyl (meth) acrylate,
Tetrahydrofurfuryl (meth) acrylate, benzyl (meth) acrylate, ethoxyethyl (meth) acrylate, ethyl carbitol (meth) acrylate,
2-hydroxy-3-chloropropyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, 1H, 1H, 5H-octa Examples include fluoropentyl (meth) acrylate, phenyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and cyclohexyl (meth) acrylate.

The mixing ratio of the polyfunctional (meth) acrylate monomer (a ₁ ) and the monofunctional (meth) acrylate monomer (a ₂ ) in the (meth) acrylate monomer (a) is as follows:
From the viewpoint of the hardness of the cured coating film and the adhesion to the substrate, the polyfunctional (meth) acrylate monomer (a ₁ ) has a content of 50 to 100.
Wt%, it is preferable monofunctional (meth) acrylate monomer (a ₂₎ is a mixture consisting of the ratio of 50 to 0% by weight. If the polyfunctional (meth) acrylate monomer (a ₁ ) in the mixture is less than 50% by weight, it is not possible to impart sufficient hardness to a cured coating film obtained from the obtained coating agent.

In the coating agent of the present invention,
The metal oxide fine particles (b) whose surfaces are treated with the hydrolyzate of the silane compound represented by the general formula [1], which is the other component, are silanes represented by the general formula [1]. These are inorganic fine particles in which the surface of metal oxide fine particles is modified with a hydrolyzate of a compound. In the present invention, "the surface is modified with a hydrolyzate" means that a hydrolyzate of a silane compound is retained by a condensation reaction on a part or all of the surface of the inorganic fine particles or a state in which the condensate is further retained. It means that the surface properties have been modified. In addition, the metal oxide fine particles (b) include metal oxide fine particles in which a condensation reaction between hydrolysates of a silane compound has progressed and which is held on the same fine particle surface.

In the present invention, the metal oxide fine particles (b)
Used to treat the surface of the metal oxide fine particles when obtaining
The silane compound represented by the general formula [1] that generates a hydrolyzate includes a silane compound having a mercapto group,
The same type as the polyfunctional (meth) acrylate monomer (a ₁ ),
It can be prepared by reacting a polyfunctional (meth) acrylate monomer having at least two (meth) acryloyloxy groups in the molecule. This reaction is
This reaction is known as a Michael-type addition reaction, and the reaction proceeds at room temperature without a catalyst, and the reaction speed can be increased by the catalyst. Examples of the catalyst used in this reaction include metal alkoxide, piperidine, quaternary ammonium salt, tertiary phosphine, etc. Among them, tertiary phosphine, particularly triphenyl phosphine, is preferable in view of the degree of catalytic activity and handleability.

The reaction between the silane compound having a mercapto group and the polyfunctional (meth) acrylate monomer can be accelerated by performing the reaction in a solvent. Solvents are preferred, and low-boiling alcohols such as ethanol and isopropanol are more preferred from the viewpoint of removing the solvent from the reaction product.

The silane compound having a mercapto group is preferably a compound represented by the following general formula [5].

[0030]

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Specific examples of R ¹ in the general formula [5] include methyl, ethyl, propyl, butyl, phenyl, octadecyl, 2-phenylethyl, vinyl, 3,3,3
-Trifluoropropyl, 2- (perfluoroethyl)
Ethyl, 2- (perfluorobutyl) ethyl and the like. Specific examples of R ₂ include methylene, ethylene, butylene, hexylene, propylene, decylene, and —CH ₂ C.
_{H 2 CH (CH 3) -} , - CH 2 CH (CH 3) -, - CH
Examples thereof include an unsubstituted divalent hydrocarbon group such as ₂ CH (CH ₃ ) CH ₂ — and a divalent hydrocarbon group having a substituent such as 2-hydroxypropyl. As a specific example of X,
Examples include an alkoxy group, an amino group, and an isopropenoxy group.

Examples of the silane compound having a mercapto group include, for example, γ-mercaptopyropytritrimethoxysilane, γ-mercaptopyropytritriethoxysilane, γ-
Mercaptopyropyrdimethoxysilane, γ-mercaptopyropyrethyldimethoxysilane, γ-mercaptopyropylmethyldiethoxysilane, γ-mercaptopyropyrethyldiethoxysilane, γ-mercaptopyropyryldimethoxysilane, δ-mercaptobutyltrimethoxysilane Silane, δ-mercaptopropyltriethoxysilane, δ-mercaptobutylmethyldimethoxysilane, δ
-Mercaptobutylethyldimethoxysilane, δ-mercaptobutylmethyldiethoxysilane, δ-mercaptobutylethyldiethoxysilane, γ-mercaptoisobutyltrimethoxysilane, γ-mercaptoisobutylmethyldimethoxysilane, γ-mercaptobutyltrimethoxysilane, γ -Mercaptobutylmethyltrimethoxysilane, γ-mercapto-2-hydroxypropyltrimethoxysilane, γ-mercapto-2-hydroxypropyltriethoxysilane, γ-mercapto-2-hydroxypropylmethyldimethoxysilane, γ-mercapto-2- Hydroxypropylethyldiethoxysilane, γ
-Mercaptopropyldimethylmethoxysilane, γ-mercaptopropyldiethylethoxysilane, β-mercaptoethyltrimethoxysilane, β-mercaptoethyltriethoxysilane, γ-mercaptopropyltriaminosilane and the like.

In the present invention, the metal oxide fine particles treated with the hydrolyzate of the silane compound represented by the general formula [1] include glass fiber chips, glass foils, silica, titanium oxide, alumina, talc and the like. , Mica,
Fine particles or colloidal dispersions such as clay and aluminum hydroxide are mentioned. Among them, colloidal dispersions such as silica and alumina, particularly colloidal silica are preferably used in order to obtain a cured film having good transparency.

The particle diameter of the metal oxide fine particles is not particularly limited, but preferably has an average particle diameter of 1 nm to 1 μm, and is preferably an average particle diameter in order to obtain a cured coating film having good transparency. It has a particle size of 10 to 500 nm. When using colloidal silica as the metal oxide fine particles, there is no particular limitation on the dispersion medium, but as the dispersion medium,
Water, methanol, ethanol, isopropyl alcohol, alcohols such as n-butanol, cellosolves,
Examples thereof include dimethylacetamide and xylene. Water, alcohols, and cellosolves are preferably used because the preparation of the coating agent is particularly simple.

In order to obtain the metal oxide fine particles (b), the surface treatment of the metal oxide fine particles with the hydrolyzate of the silane compound represented by the general formula [1] is carried out in the presence of the metal oxide fine particles. After hydrolyzing the compound or hydrolyzing the compound, the hydrolyzate can be easily subjected to a condensation reaction. In the surface treatment, the silane compound represented by the general formula [1] is preferably 0.1 to 500 parts by weight, more preferably 0.5 to 200 parts by weight, based on 100 parts by weight of the metal oxide fine particles. It should be done in.

The metal oxide fine particles obtained under the condition that the amount of the silane compound is less than 0.5 part by weight have poor dispersion stability in the coating agent, and the metal oxide fine particles obtained under the condition from 200 parts by weight. The coating agent containing fine particles tends to have a high viscosity and is expensive in terms of cost.

As a catalyst for promoting the hydrolysis of the silane compound, an inorganic acid or an organic acid can be used. Examples of the inorganic acid include hydrochloric acid, hydrofluoric acid, hydrohalic acid such as hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like.Examples of the organic acid include formic acid, acetic acid, and the like.
Examples include oxalic acid and (meth) acrylic acid. Organic acids can be used.

In the reaction system for hydrolyzing the silane compound in obtaining the metal oxide fine particles (b), a solvent can be used in order to carry out the reaction mildly and uniformly. The solvent used is preferably a silane alkoxide that is a hydrolyzate, one that is compatible with water and a catalyst, for example, water, methanol, ethanol, alcohols such as isopropyl alcohol, acetone, ketones such as methyl isobutyl ketone, Ethers such as tetrahydrofuran and dioxane; The amount of the solvent used is such that if the concentration of the reactant is too low, the reaction rate tends to be extremely slow, so long as the reactant can be uniformly dissolved.
There is no particular limitation.

The hydrolysis and condensation reaction of the silane compound represented by the general formula [1] in the presence of the metal oxide fine particles may be carried out at a temperature of 20 to 120 ° C. for 30 minutes, depending on the amount of the solvent used. It is sufficient to use a solvent having a boiling point of 20 ° C. or higher for 1 to 10 hours under the conditions of the boiling point.

In the coating agent of the present invention, there are provided (meth) acrylate monomer (a) and metal oxide fine particles (b) surface-treated with a hydrolyzate of a silane compound represented by the above general formula [1]. Is not particularly limited,
Preferably, the amount of the (meth) acrylate monomer (a) is in the range of 5 to 2,000 parts by weight with respect to 100 parts by weight of the metal oxide fine particles (b). In consideration of the viscosity of the coating agent, (meth) acrylate monomer (a)
A range of 00 parts by weight is preferred.

The coating agent of the present invention can be cured by thermal polymerization and / or photopolymerization, and a polymerization initiator can be appropriately added to the coating agent of the present invention in order to accelerate the curing reaction. Examples of the polymerization initiator include thermal polymerization initiators such as lauroyl peroxide, benzoyl peroxide, propionoyl peroxide, t-butylperoxylaurate, dicumyl peroxide, di-t-butyl peroxide, cumene hydro. Peroxide initiators such as peroxides,
2,2′-azobisisobutyronitrile, 1,1′-azobis-1-cyclopentanonitrile, dimethyl-2,
2'-azobisisobutyrate, 1,1'-azobiscyclohexanecarbonitrile, 4,4'-azobis-4
-Cyanovaleic acid, 2,2'-azobis-2-
An azo initiator such as benzylpropionitrile and the like can be mentioned.

As the photopolymerization initiator, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, acetoin, butyroin, toluoin, benzyl, benzophenone, p-methoxybenzophenone, 2,2-diene Ethoxyacetophenone, α, α
-Dimethoxy-α-phenylacetophenone, methylphenylglyoxylate, ethylphenylglyoxylate, 4,4′-bis (dimethylamino) benzophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, , 4,6-trimethylbenzoyldiphenylphosphine oxide, benzoyldiethoxyphosphine oxide, thioxanthone, 2-chlorothioxanthone, 2,4-dichlorothioxanthone, 2-
Methylthioxanthone, 2,4-dimethylthioxanthone, 2-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, etc., and particularly 2,4,6-trimethylbenzoyldiphenylphosphine oxide, benzoyldiethoxyphosphone Fin oxide is preferred.

These thermal polymerization initiators and photopolymerization initiators are
Used alone or as a mixture. The amount of the polymerization initiator added to the coating agent is 100
It is preferably 0.01 to 10 parts by weight based on parts by weight. If the amount of the polymerization initiator is less than 0.01 part by weight, the effect as the polymerization initiator tends to be insufficient, and 10
If the amount is more than 10 parts by weight, coloring of the cured coating film and poor weather resistance tend to occur.

If necessary, additives such as a surface smoothing agent, a surfactant, an ultraviolet absorber, a light stabilizer, a heat stabilizer and a storage stabilizer may be added to the coating agent of the present invention. .

The coating agent of the present invention can be used as a solventless type, but if necessary, may contain an organic solvent. As the organic solvent, particularly, it is possible to uniformly mix the (meth) acrylate monomer (a) and the polymerization initiator and to uniformly disperse the metal oxide fine particles (b). Although not limited, those having a boiling point at normal pressure of 50 to 200 ° C and a viscosity at 25 ° C of 10 centipoise or less are suitable.

Examples of the organic solvent used include alcohols such as ethanol, isopropyl alcohol, normal propyl alcohol and normal butyl alcohol, aromatic hydrocarbons such as benzene and toluene, ketones such as acetone and methyl ethyl ketone, and dioxane. Ethers, esters such as ethyl acetate and butyl acetate,
N, N-dimethylformamide and the like. These solvents are used alone or in combination of two or more.

When the coating agent of the present invention is applied to the surface of a resin molded product and this coating layer is cured by radical polymerization, a cured coating film having a high surface hardness can be formed. Accordingly, another aspect of the present invention is a resin molded product having a cured coating film obtained by radical polymerization of a coating layer obtained by applying a coating agent to the surface of the resin molded product.

The cured coating film in the resin molded article having the cured coating film of the present invention, via a structure represented by the following general formula [6], a polymer comprising the (meth) acrylate monomer (a) The cured coating film is bonded to the metal oxide fine particles (b). The cured coating film bonded by the structure represented by the general formula [6] not only has a performance of very high surface hardness, but also has good heat moldability. Even after heat molding a resin molded product having
It maintains the same high surface hardness as before heat molding.

[0049]

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The structure represented by the general formula [6] has a metal oxide fine particle (b) obtained by adding a silane coupling agent having a mercapto group to the surface of the metal oxide fine particle, and a (meth) acrylate monomer By mixing (a) and performing radical polymerization, it can be obtained by reacting the mercapto group of the silane coupling agent with the (meth) acrylate group of the (meth) acrylate polymer by a chain transfer reaction.

Specifically, the resin molded article having the cured coating film of the present invention can be obtained, for example, by the following method. First, in the (meth) acrylate monomer (a) or a partial condensate thereof, metal oxide fine particles in which the surface of the metal oxide fine particles is modified with a hydrolyzate of a silane compound represented by the above general formula [1] (B) is added to obtain a preparation liquid (coating agent). When this preparation liquid is applied to a resin molded product and cured by heat and / or light, the above-mentioned general formula [6]
A resin molded article having a cured coating film in which the (meth) acrylate polymer and the metal oxide fine particles (b) are bonded via the structure represented by

The resin molded article on which the cured coating film is formed by the coating agent of the present invention is not particularly limited, and examples thereof include a molded article of a known resin such as an acrylic resin and a polycarbonate resin. In particular, the cured coating film obtained by curing the coating agent of the present invention is excellent in transparency, scratch resistance, and abrasion resistance. It is suitable for an optical component material requiring transparency, scratch resistance and abrasion resistance.

Further, the resin molded article having the cured coating film of the present invention has good transparency, scratch resistance and abrasion resistance even after heat molding such as bending, so that the head for automobiles can be obtained. It can be used for applications such as lamp cases, motorcycle helmet shields, vehicle window materials, refrigerated or frozen showcase window materials, and resin building materials.

[0054]

The present invention will be described below in more detail with reference to examples. In addition, the measurement and evaluation of each physical property in the examples were based on the following methods.

<Total Light Transmittance> According to JIS K7105, the total light transmittance was measured using a reflection transmittance meter (manufactured by Murakami Color Research Laboratory, product number HR-100).

<Adhesion> 11 cuts were made on the cured coating surface of the sample at 1 mm intervals vertically and horizontally with a razor blade.
After making zero eyes and attaching cellophane tape (adhesive tape manufactured by Nichiban Co., Ltd.) to the surface of the eyes, it was peeled off at a stretch in the direction of 90 °, leaving the cured coating film without peeling from the substrate. The number of eyes (n) is indicated by n / 100.

<Haze Value and Scratch Resistance> A # 000 steel wool was mounted on a circular pad surface having a diameter of 25 mm, and a sample piece was fixed on a reciprocating friction tester table with the cured coating surface facing up. A circular pad was placed so that the steel wool surface was in contact with the cured coating surface, and the test machine was operated under a load of 1000 g under a load of 1000 g.
Zero reciprocation was performed, and a steel wool test of the cured coating film of the sample piece was performed. After the steel wool test was completed, the sample piece was washed and dried, and then the haze value of the cured coating film of the sample piece was measured as a haze value using a haze meter. Scratch resistance (%) = Haze value (%) of test piece after steel wool test-Haze value (%) of test piece before steel wool test

<Abrasion resistance> Regarding the cured coating film of the sample piece,
Using the Taber abrasion test method, using a CS-10F wear wheel, a wear test was performed at 100 rotations and 500 rotations with a load of 500 g per wheel, and the haze value of the wear portion of the sample piece was measured with a haze meter, and the value was calculated by the following equation. Was determined to have scratch resistance. The haze was measured at four points on the trajectory of the wear cycle, and the average value was obtained. Abrasion resistance (%) = Haze value (%) of test piece after Taber abrasion test-Haze value (%) of test piece before Taber abrasion test

(Example 1) 133 parts by weight of isopropanol, 104 parts by weight of 1,6-hexanediol diacrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd .; hereinafter, referred to as C6DA), γ-mercaptopyropyrpropyltrimethoxysilane (Shinetsu Silicone) Manufactured by KBM-803) 30 parts by weight,
Triphenylphosphine (hereinafter referred to as TPP) 0.6
The mixture consisting of parts by weight was stirred at room temperature for 72 hours to prepare a silane compound-containing mixture (A).

While stirring 125 parts by weight of isopropanol-dispersed colloidal silica (manufactured by Nissan Chemical Industries, Ltd., IPA-ST, solid content: 30% by weight), 100 parts by weight of the silane compound-containing mixture (A) and 0.01 part by weight were mixed. 4.5 parts by weight of a specified hydrochloric acid was added, and the mixture was stirred at 40 ° C. for 1 hour to hydrolyze the silane compound in the silane compound-containing mixture (A), and a condensation reaction between the hydrolyzate and silica was performed.
A surface-modified silica was obtained. Then, C6DA21.9
4 parts by weight of a polyester acrylate (hereinafter referred to as TAS) obtained by a condensation reaction of trimethylolethane / succinic acid / acrylic acid (molar ratio 2: 1: 4) were added, and the mixture was stirred uniformly. The pressure was reduced to remove volatile components, to obtain a dispersion (B).

To 100 parts by weight of the obtained dispersion (B), 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Luc, manufactured by BASF, Inc.) was used as a photopolymerization initiator.
2.8 parts by weight of irin TPO (hereinafter, referred to as TPO) and 1 part by weight of benzophenone (manufactured by Wako Pure Chemical Industries, Ltd.) were added and dissolved by stirring to obtain a coating agent.

The obtained coating agent is applied to a 2 mm-thick polycarbonate plate (Dialite P, manufactured by Mitsubishi Rayon Co., Ltd .; hereinafter, referred to as a PC plate), and a thickness of 5 mm is applied to the coated surface.
A biaxially stretched film of polyethylene terephthalate having a thickness of 0 μm was covered and laminated, and the thickness was set to 8 μm with a rubber roll. Then, after holding in an atmosphere of 70 ° C. for 40 minutes,
After passing through a 120 W / cm metal halide lamp (distance 210 mm) at a speed of 1.6 m / min with the film surface facing upward at a speed of 1.6 m / min, the first stage of curing is performed, and after the film is peeled off, the coating surface is oriented upward. Then, it passed under a high-pressure mercury lamp with an output of 120 W / cm (distance 210 mm) at a speed of 1.6 m / min to perform the second-stage curing. Table 1 shows the evaluation results of the obtained surface-hardened PC boards.

Example 2 A coating agent was obtained in the same manner as in Example 1 except that TAS was changed to dipentaerythritol hexaacrylate (KAYARAD DPHA, manufactured by Nippon Kayaku Co., Ltd.). . Using this coating agent, a PC board having a cured coating film formed thereon was obtained in the same manner as in Example 1. Obtained surface-hardened PC
Table 1 shows the evaluation results of the plates.

Example 3 A coating agent was obtained in the same manner as in Example 1 except that TAS was changed to trimethylolpropane acrylate (TMPTA, manufactured by Osaka Organic Chemical Industry Co., Ltd.). Using this coating agent, a PC board having a cured coating film formed thereon was obtained in the same manner as in Example 1. Table 1 shows the evaluation results of the obtained surface-hardened PC boards.

Example 4 The procedure of Example 1 was repeated, except that the TAS was replaced by tritris (2-hydroxyethyl) isocyanurate diacrylate (Aronix M-215, manufactured by Toa Gosei Chemical Industry Co., Ltd.). In the same manner as in Example 1, a coating agent was obtained. Further, a PC having a cured coating film formed using this coating agent in the same manner as in Example 1
I got a board. Table 1 shows the evaluation results of the obtained surface-hardened PC boards.

Example 5 A 3 mm thick polymethyl methacrylate plate (Acrylite L, manufactured by Mitsubishi Rayon Co., Ltd .;
PMMA plate), a 50 μm-thick biaxially stretched film of polyethylene terephthalate was put on the coated surface and laminated, and the film thickness was set to 8 μm with a rubber roll. Next, after holding for 40 minutes in an atmosphere of 70 ° C., the film was passed under a metal halide lamp having an output of 120 W / cm (distance 210 mm) at a speed of 1.6 m / min with the film surface facing upward to cure the first stage. After the film was peeled off, the film was passed under a high-pressure mercury lamp with an output of 120 W / cm (distance 210 mm) at a speed of 1.6 m / min with the coating surface facing upward to perform second-stage curing. Table 1 shows the evaluation results of the obtained surface-hardened PMMA plates.

(Example 6) Using the coating agent obtained in Example 2 and forming a cured coating film in the same manner as in Example 5,
An MMA plate was obtained. Table 1 shows the evaluation results of the obtained surface-hardened PMMA plates.

(Comparative Example 1) TAS 40 parts by weight, C6D
A 60 parts by weight, 2.8 parts by weight of TPO, and 1 part by weight of benzophenone were mixed and dissolved by stirring to obtain a coating agent. The obtained coating agent is applied to a PC board having a thickness of 2 mm, a biaxially stretched film of polyethylene terephthalate having a thickness of 50 μm is put on the application surface, and a film thickness of 8 is applied with a rubber roll.
It was set to μm. Then, output 1 with the film side up
Under a 20 W / cm metal halide lamp (distance 210
mm) at a speed of 1.6 m / min to cure the first stage, peel off the film, put it on the coating surface and output 120 W
/ M under a high pressure mercury lamp (distance 210 mm) is 1.6 m
/ Min and a second stage of curing was performed. Table 1 shows the evaluation results of the obtained surface-hardened PC boards.

Comparative Example 2 A coating agent was obtained in the same manner as in Comparative Example 1, except that TAS was changed to dipentaerythritol hexaacrylate. Further, a PC board having a cured coating film formed thereon was obtained in the same manner as in Comparative Example 1 using this coating agent. Obtained surface hardening P
Table 1 shows the evaluation results of the C plate.

(Reference Examples 1 and 2) Untreated PC board and PM
Table 1 also shows the evaluation results of the MA plate.

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[Table 1]

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The coating agent of the present invention is a coating agent which can impart high surface hardness to a resin molded product and can be made solvent-free. The resin molded article having the cured coating film of the coating agent of the present invention has a high surface hardness and is particularly suitable as a transparent resin molded article.

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI C09D 183/08 G02B 1/10 Z

Claims (4)

[Claims] 1. Metal oxide fine particles whose surfaces are treated with a (meth) acrylate monomer (a) or a partial condensate thereof and a hydrolyzate of a silane compound represented by the following general formula [1]: A coating agent comprising (b). Embedded image 2. The method according to claim 1, wherein the (meth) acrylate monomer (a) is
Polyfunctional (meth) acrylate monomer having at least two (meth) acryloyloxy groups in the molecule (a ₁ )
50-100% by weight and copolymerizable therewith monofunctional (meth) acrylate monomer (a ₂₎ a coating agent according to claim 1 which is a mixture consisting of 50 to 0% by weight. 3. The coating agent according to claim 1, wherein the metal oxide fine particles are colloidal silica. 4. A resin molded article having a cured coating film obtained by radical polymerization of a coating layer obtained by applying the coating agent according to claim 1, 2 or 3 on the surface of the resin molded article.