JPH06322291A - Coating composition and surface-coated molded product - Google Patents

Abstract

PURPOSE:To obtain a coating compsn. capable of forming a cured coating film excellent in abrasion resistance, solvent resistance, scuff resistance, weatherability and water resistance, by using a specific cross-linking- polymerizable compd., specific silica particles and a specific photopolymn, initiator. CONSTITUTION:A coating compsn. comprises a cross-linking-polymerizable compd. having at least 2 (meth)acryloyloxy groups (e.g., 1,6-hexanediol diacrylate) per molecule or a mixture of at least 50wt.% of the above-mentioned compd. and a compd. copolymerizable therewith, silica particles having the surfaces thereof modified with the hydropyzate of a silane compd. of the formula [R<1> and R<2> are each H or a 1-10C hydrocarbon group; R<3> is an (ether bond- and/or carbonyl bond-contg.) bivalent 1-10C hydrocarbon group; R<4> is a bivalent 1-10C hydrocarbon group; R<5> is a 1-3C hydrocarbon group; R<6> is H or a 1-10C hydrocarbon group; m is 0 to 1; and n is 0 to 2], and a photopolymn initiator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition capable of forming a coating film having excellent abrasion resistance and solvent resistance by irradiation with an active energy ray, and a cured film of this coating composition. The present invention relates to a surface-coated molded product such as a synthetic resin molded product coated with.

[0002]

2. Description of the Related Art In recent years, it has been widely practiced to use a transparent plastic material having a high crush resistance as a substitute for transparent plate glass. However, transparent plastic materials have the significant drawbacks of having a softer surface than glass and being prone to surface wear and scratches.

Many attempts have hitherto been made to improve the wear resistance of plastics. One of the most common methods is, for example, as described in JP-A-53-102936, JP-A-53-104638, JP-A-54-97633 and the like, a plurality of acryloyloxy groups or methacryloyl groups in the molecule. There is a method in which a compound having an oxy group is applied to a molded article and cured by heat or active energy rays such as ultraviolet rays to obtain a molded article having excellent scratch resistance. In this method, the curing liquid is relatively inexpensive and the productivity is excellent, but at present the abrasion resistance of the coated molded article is limited because the cured coating is an organic material.

On the other hand, in order to impart a higher surface hardness to the molded product, for example, JP-A-48-26822 and JP-A-5-26822.
A method of applying an alkoxysilane compound as described in JP-A-9-64671 to the surface of a plastic molded article and curing it by heat, or JP-A-56-106969.
Japanese Patent Laid-Open No. 272041/1990 discloses a method in which a mixture of colloidal silica and an organic resin is applied to the surface of a plastic molded article and cured by heat. However, since a solvent is used in these methods, a drying step is required, which tends to cause a problem in the appearance of the coated molded product, and since it needs to be cured by heat, it consumes a large amount of energy. This is industrially disadvantageous because it takes a long time. Further, drying with a solvent is not preferable from the viewpoint of protection of the global environment, which has recently received a great deal of attention.

On the other hand, Japanese Patent Publication No. 1-55307 and 3
-2168 gazette, the same 3-6190 gazette, JP-A-59.
-204669, 62-256874,
JP-A-2-64138, JP-A-4-18423 and JP-B-62-21815 disclose a coating composition comprising colloidal silica, an alkoxysilane having an acryl group or a methacryl group, and a polyfunctional acrylate. It is disclosed. These can be used without a solvent if necessary, and can impart a considerably excellent surface hardness to a plastic molded product, but due to the hydrophilic property derived from the structure of the acryl group or methacryl group in the alkoxysilane compound, The interface of the colloidal silica and the alkoxysilane in the coating film is easily hydrolyzed, resulting in deterioration of the weather resistance and water resistance of the coating film.

Further, Japanese Patent Laid-Open No. 3-56514 discloses that
A coating composition is disclosed which comprises a polyfunctional acrylate partially modified with an aminoorganofunctional silane and colloidal silica. According to the disclosure, in the sense of utilizing a compound having both an acrylic group and an alkoxysilyl group, which is obtained by Michael-adding an aminoorganofunctional silane to a part of double bonds in a polyfunctional acrylate, The above, colloidal silica, and an alkoxysilane having an acrylic group or a methacrylic group,
It is considered similar to coating compositions consisting of polyfunctional acrylates.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art. That is, the object of the present invention is a coating composition that can be applied without using a solvent, and is excellent in abrasion resistance, scratch resistance and weather resistance due to curing, water resistance, high surface hardness and good appearance. It is intended to provide a coating composition capable of forming a film, and a molded article whose surface is coated with a cured product of the coating composition.

[0008]

The present invention provides (a) a crosslinkable polymerizable compound (a) having at least two acryloyloxy groups and / or methacryloyloxy groups in the molecule (a).
-1) or a mixture of 50% by weight or more of the crosslinkable compound (a-1) and a compound (a-2) copolymerizable therewith,

[0009]

[Chemical 2] (B) General formula (I) (in the formula, R ¹ and R ² are each independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms,
R ³ is a divalent hydrocarbon group having 1 to 10 carbon atoms which may have an ether bond and / or a carbonyl bond, R 3
⁴ is a divalent hydrocarbon group having 1 to 10 carbon atoms, R ⁵ is a hydrocarbon group having 1 to 3 carbon atoms, R ⁶ is a hydrogen atom or 1 to carbon atoms
10 hydrocarbon groups, m represents 0 or 1, and n represents an integer of 0 to 2). A coating composition comprising silica particles whose surface is modified with a hydrolyzate of a silane compound represented by and (c) a photopolymerization initiator. In addition, another invention is
An article whose surface is coated with a cured product of such a coating composition.

[0010]

In the coating composition of the present invention, the surface of the silica particles (b) is modified with the hydrolyzate of the silane compound represented by the general formula (I). The silica particles (b) can be dispersed at a high concentration, and the above-mentioned objects such as improvement of abrasion resistance can be achieved. Furthermore, since the silane compound represented by the general formula (I) has hydrogen bonded to the carbon adjacent to the nitrogen atom, it acts as a hydrogen donor and forms a complex with the photopolymerization initiator (c). It has the function of generating radicals. For example, when benzophenone is used as the photopolymerization initiator (c), the following reaction occurs upon irradiation with active energy rays.

[0011]

[Chemical 3] Further, the hydrogen bonded to the carbon adjacent to the nitrogen atom in the silane compound represented by the general formula (I) is also abstracted by the radical growing during the polymerization to generate a reinitiable radical.

For these reasons, radicals are generated in the silane compound represented by the general formula (I) bonded to the surface of silica particles by irradiation with active energy rays, and polymerization of the component (a) is caused. The component (a) polymer is firmly bonded to the silica surface, and the cured coating film exhibits high surface hardness. More notably, the coating composition of the present invention can improve the weather resistance and water resistance of the coating film, which has been a problem in the prior art.

The present invention will be described in detail below.

Component (a) in the coating composition of the present invention
Is a crosslinkable polymerizable compound having at least two acryloyloxy groups and / or methacryloyloxy groups (hereinafter abbreviated as (meth) acryloyloxy group) in the molecule.
It is (a-1). The component (a) is composed of 50% by weight or more of the crosslinkable compound (a-1) and a compound (a) copolymerizable therewith.
-2) and may be a mixture.

Crosslinkable polymerizable compound (a-1) having at least two (meth) acryloyloxy groups in the molecule
Is a hydrocarbon or a derivative thereof, which is a moiety other than the (meth) acryloyloxy group, and may have an ether bond, a thioether bond, an ester bond, an amide bond, a urethane bond, etc. in its molecule. .

As the crosslinkable compound (a-1), for example, an ester compound obtained from a polyhydric alcohol and (meth) acrylic acid or a derivative thereof, or a polyhydric alcohol, a polycarboxylic acid and (meth) acrylic Examples thereof include ester compounds obtained from acids or their derivatives. Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and an average molecular weight of about 30.
0 to about 1000 polyethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol (ie 2,2-dimethyl-1,3-propanediol), 2-ethylhexyl-1,3-hexanediol, 2,2′-thiodiethanol, 1,4-cyclohexane Dihydric alcohols such as dimethanol; trimethylolpropane (ie 1,1,1-trimethylolpropane), pentaglycerol (ie 1,1,1-trimethylolethane), glycerol, 1,2,4-butanetriol , 1,2,6-hexanetriol and other trivalent alcohols; Others , Pentaerythritol (ie 2,
2-bis (hydroxymethyl) -1,3-propanediol), diglycerol, dipentaerythritol and the like can be mentioned.

As an example of the crosslinkable polymerizable compound (a-1) obtained as a poly (meth) acrylate of a polyhydric alcohol,
The following general formula (II)

[0018]

[Chemical 4] (In the formula, n represents an integer of 0 to 4, and four or more Xs present in the molecule have two or more of them represent a (meth) acryloyloxy group, and the rest are each independently a hydrogen atom or a hydroxyl group. , An amino group, an alkyl group or a substituted alkyl group).

Specific examples of the compound represented by the general formula (II) include trimethylolpropane tri (meth).
Acrylate, trimethylolethane tri (meth) acrylate, pentaglycerol tri (meth) acrylate, pentaerythritol tri (meth) acrylate,
Pentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tripentaerythritol tetra (meth) acrylate ) Acrylate, tripentaerythritol penta (meth) acrylate,
Examples include tripentaerythritol hexa (meth) acrylate and tripentaerythritol hepta (meth) acrylate.

Examples of poly (meth) acrylates of polyhydric alcohols other than the compound of the general formula (II) include diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth). ) Acrylate, 1,4-
Examples thereof include butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, glycerin tri (meth) acrylate and the like.

When an ester compound obtained from a polyhydric alcohol and (meth) acrylic acid is used as the crosslinkable polymerizable compound (a-1), particularly preferable ester compounds are diethylene glycol di (meth) acrylate and triethylene glycol di ( (Meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaglycerol triacrylate , Dipentaglycerol pentaacrylate and the like.

The ester compound obtained from the polyhydric alcohol, polyvalent carboxylic acid, and (meth) acrylic acid or their derivatives which can be used as the crosslinkable polymerizable compound (a-1) is basically a polyhydric alcohol. It can be obtained by reacting a mixture in which the hydroxyl groups of γ and the carboxyl groups of both polyvalent carboxylic acid and (meth) acrylic acid are finally equivalent. Among these ester compounds, preferred are polyhydric alcohols which are dihydric alcohols, trihydric alcohols, or a mixture of dihydric alcohols and trihydric alcohols, and which are used as polyhydric carboxylic acids. The esterified product obtained by using. When a mixture of trihydric alcohol and dihydric alcohol is used, the molar ratio of the trihydric alcohol and the dihydric alcohol may be arbitrarily selected. When the divalent carboxylic acid and (meth) acrylic acid are used in combination, the molar ratio is such that the carboxyl group of the divalent carboxylic acid is 2 mol or less with respect to 1 mol of the carboxyl group of (meth) acrylic acid. Preferably. When the divalent carboxylic acid is in excess of the above range, the viscosity of the produced ester may be too high, and it may be difficult to form a coating film.

Examples of the divalent carboxylic acid or its derivative used in the synthesis of the above-mentioned ester compound include aliphatic dicarboxylic acids such as succinic acid, adipic acid and sebacic acid; tetrahydrophthalic acid and 3,6-endomethylenetetrahydrophthalic acid. Alicyclic dicarboxylic acids such as; phthalic acid, isophthalic acid, terephthalic acid and other aromatic dicarboxylic acids; other thiodiglycolic acid, thiodivaleric acid,
Diglycolic acid, maleic acid, fumaric acid, itaconic acid,
And chlorides, anhydrides and esters thereof.

Specific examples of the above-mentioned ester compound used as the crosslinkable polymerizable compound (a-1) are malonic acid / trimethylolethane / (meth) acrylic acid, malonic acid / trimethylolpropane / (meth) acrylic acid, and malon. Acid / glycerin / (meth) acrylic acid, malonic acid / pentaerythritol / (meth) acrylic acid, succinic acid / trimethylolethane / (meth) acrylic acid, succinic acid / trimethylolpropane / (meth) acrylic acid, succinic acid / Glycerin / (meth) acrylic acid, succinic acid / pentaerythritol / (meth) acrylic acid, adipic acid / trimethylolethane / (meth) acrylic acid, adipic acid / trimethylolpropane / (meth) acrylic acid, adipic acid /
Pentaerythritol / (meth) acrylic acid, adipic acid / glycerin / (meth) acrylic acid, glutaric acid / trimethylolethane / (meth) acrylic acid, glutaric acid / trimethylolpropane / (meth) acrylic acid, glutaric acid / glycerin / (Meth) acrylic acid, glutaric acid / pentaerythritol / (meth) acrylic acid, sebacic acid / trimethylolethane / (meth) acrylic acid, sebacic acid / trimethylolpropane / (meth) acrylic acid, sebacic acid / glycerin / (Meth) acrylic acid, sebacic acid / pentaerythritol / (meth) acrylic acid, fumaric acid / trimethylolethane / (meth) acrylic acid, fumaric acid / trimethylolpropane / (meth) acrylic acid, fumaric acid / glycerin / ( (Meth) acrylic acid, fumaric acid / penta Risuritoru / (meth) acrylic acid, itaconic acid / trimethylolethane / (meth) acrylic acid, itaconic acid / trimethylolpropane / (meth) acrylic acid, itaconic acid / pentaerythritol /
It is a saturated or unsaturated polyester polyacrylate or polymethacrylate obtained by a combination of compounds such as (meth) acrylic acid, maleic anhydride / trimethylolethane / (meth) acrylic acid, maleic anhydride / glycerin / (meth) acrylic acid.

Further, as the crosslinkable polymerizable compound (a-1), for example, trimethylolpropane toluylene triisocyanate, the following general formula (III)

[0026]

[Chemical 5] (In the formula, each R independently represents hexamethylene diisocyanate, tolylene diisocyanate, diphenylethane diisocyanate, xylene diisocyanate, 4,4 ′.
Represents the residue of methylenebis (cyclohexylisocyanate), isophorone diisocyanate or trimethylhexamethylene diisocyanate. And a polyisocyanate such as a compound represented by the formula (1) and an acrylic monomer having active hydrogen (for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxy-3-methoxypropyl (meth) acrylate, N-methylol (meth)). Acrylamide, N-hydroxy (meth) acrylamide, etc.)
And a urethane (meth) acrylate obtained by reacting 1 mol or more of an acrylic monomer per 1 mol of an isocyanate group by a conventional method; and a poly [[tri (meth) acrylate] such as tris (2-hydroxyethyl) isocyanuric acid. (Meth) acryloyloxyethyl] isocyanurate.

Component (a) in the coating composition of the present invention
May be a mixture of 50% by weight or more of the crosslinkable compound (a-1) and the compound (a-2) copolymerizable therewith. As the copolymerizable compound (a-2), for example, a compound having one (meth) acryloyl group in the molecule is used. Specifically, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate,
t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-hydroxyethyl (meth)
Acrylate, 2-hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, benzyl (meth)
Acrylate, 1,4-butylene glycol mono (meth) acrylate, ethoxyethyl (meth) acrylate, ethylcarbitol (meth) acrylate, 2-hydroxy-3-chloropropyl (meth) acrylate,
(Meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, N-hydroxypropyl (meth) acrylamide, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,2 3,3-Tetrafluoropropyl (meth) acrylate, 1H, 1H, 5H-octafluoropentyl (meth) acrylate, N-hydroxybutyl (meth) acrylamide, hydroxymethyldiacetone (meth) acrylamide, N-hydroxyethyl-
N-methyl (meth) acrylamide, the following general formula (IV)
Or (V)

[0028]

[Chemical 6]

[0029]

[Chemical 7] (In the general formulas IV and V, n represents 1 to 10, X represents a (meth) acryloyloxy group, R represents an alkyl group, a substituted alkyl group, a phenyl group, a substituted phenyl group, a benzyl group or a substituted benzyl group. Shown)), and the like.

Examples of the mono (meth) acrylate represented by the general formula (IV) or (V) include methoxydiethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, butoxyethylene. Examples thereof include glycol (meth) acrylate.

Further as the copolymerizable compound (a-2), for example, β- (meth) acryloyloxyethyl hydrogen phthalate, β- (meth) acryloyloxyethyl hydrogen succinate, β- (meth) acryloyloxypropyl hydrogen succinate. And various known epoxy (meth) acrylates, urethane (meth) acrylates, and the like.

Component (b) in the coating composition of the present invention
Is silica particles whose surface is modified with a hydrolyzate of a silane compound represented by the general formula (I). Here, "the surface is modified with a hydrolyzate" means that the hydrolyzate of the silane compound is retained on a part or the whole of the surface of the silica particles, whereby the surface characteristics are modified. Means that. In addition, the silica particles in which the hydrolyzate, which has undergone the condensation reaction, is simultaneously held are also included. This surface modification in the present invention can typically be easily carried out by causing hydrolysis of a silane compound or a hydrolysis and condensation reaction in the presence of silica particles.

Colloidal silica can be used as the silica particles. The average particle size of silica is usually 1 nm to 1
The average particle size is preferably 10 nm to 500 nm, although it is not particularly limited. When colloidal silica is used, its dispersion medium is not particularly limited, but usually water; alcohols such as methanol, ethanol, isopropyl alcohol, n-butanol; cellosolves; dimethylacetamide, xylene and the like are used. Particularly preferred dispersion media are alcohols, cellosolves and water.

Examples of the silane compound represented by the general formula (I) used in the present invention include H ₂ NC ₃ H ₆ Si (O
_{CH 3) 3, H 2 NC} 3 H 6 Si (OC 2 H 5) 3,

[0035]

[Chemical 8] _{CH 3 NHC 3 H 6 Si (} OCH 3) 3, C 2 H 5 NH
C ₃ H ₆ Si (OCH ₃ ) ₃ ,

[0036]

[Chemical 9] _{H 2 NC 2 H 4 NHC 3} H 6 Si (OCH 3) 3,

[0037]

[Chemical 10] Etc. and mixtures thereof.

Component (b) in the coating composition of the present invention
In order to obtain the above, only the silane compound represented by the general formula (I) may be hydrolyzed and condensed in the presence of silica particles, or may be cohydrolyzed and condensed with another silane compound. Such other silane compounds include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetra-i-propoxysilane, tetra-n-butoxysilane, tetrahexyl orthosilicate, tetraphenyl orthosilicate, tetrabenzyl orthosilicate, methyl. Trimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, diphenyldimethoxysilane, methylethyldiethoxysilane, methylphenyldimethoxysilane, methoxy Examples thereof include ethyltriethoxysilane and trimethylmethoxysilane.

When colloidal silica is used as the silica particles, the silane compound is mixed in a dispersion of colloidal silica and hydrolyzed by water in the system or newly added water to modify the surface with the hydrolyzate. The obtained silica particles (b) are obtained. An inorganic acid or an organic acid can be used as a catalyst for the hydrolysis reaction of the silane compound. Examples of the inorganic acid include hydrohalic acid such as hydrochloric acid, hydrofluoric acid, hydrobromic acid, sulfuric acid, nitric acid,
Phosphoric acid or the like is used. Organic acids include formic acid, acetic acid,
Examples thereof include oxalic acid, acrylic acid and methacrylic acid.

A solvent can be used in the hydrolysis reaction system of the silane compound in order to carry out the reaction mildly and uniformly. As this solvent, those capable of compatibilizing the reaction product silane alkoxide with water and the catalyst are desirable. Specific examples thereof include water; alcohols such as methanol, ethanol and isopropyl alcohol; ketones such as acetone and methyl isobutyl ketone; ethers such as tetrahydrofuran and dioxane. As the solvent, the above-mentioned colloidal silica dispersion medium may be used as it is, or a necessary amount may be newly added. The amount of the solvent used is not particularly limited as long as it can dissolve the reaction product uniformly, but if the concentration of the reaction product becomes too dilute, the reaction rate may be significantly slowed down. The hydrolysis and condensation reaction of the silane compound is carried out at a temperature of room temperature to about 120 ° C. for 30 minutes to 24 hours.
It is carried out under the condition of about time, preferably at room temperature to the boiling point of the solvent for about 1 to 10 hours.

The compounding ratio of the component (b) is not particularly limited, but the silane compound is preferably 5 to 200 parts by weight, more preferably 25 to 100 parts by weight with respect to 100 parts by weight of silica particles (solid content in the case of colloidal silica). Use 100 parts by weight. Further, the compounding ratio of the component (a) and the component (b) is not particularly limited, but, relative to 100 parts by weight of the silica particles (solid content in the case of colloidal silica) in the component (b),
The component (a) is preferably used in an amount of 5 to 1000 parts by weight, more preferably 20 to 200 parts by weight.

The photopolymerization initiator (c) in the coating composition of the present invention is capable of causing the polymerization reaction of the component (a). Specific examples include benzoin, benzoin methyl ether and benzoin ethyl ether. , Benzoin isopropyl ether, benzoin isobutyl ether, acetoin, butyroin, toluoin, benzyl,
Carbonyl compounds such as benzophenone and p-methoxybenzophenone; sulfur compounds such as tetramethylthiuram monosulfide and tetramethylthiuram disulfide; azobisisobutyronitrile and azobis-2,4-
Examples thereof include azo compounds such as dimethylvaleronitrile; peroxide compounds such as benzoyl peroxide and ditert-butyl peroxide; and phosphine oxide compounds such as trimethylbenzoyldiphenylphosphine oxide and benzoyldiethoxyphosphine oxide. These polymerization initiators may be used alone or in combination of two or more. The photopolymerization initiator (c) which is particularly suitable for use in the present invention is one capable of forming a complex with a hydrolyzate of a silane compound having a methylene hydrogen adjacent to a nitrogen atom. When an initiator is used, the hydrogen bonded to carbon is abstracted by the mechanism described above to initiate radical polymerization, so that the polymer of component (a) is firmly bonded to the surface of silica via the hydrolyzate of the silane compound. be able to. Specific examples of such a photopolymerization initiator include:
Mention may be made of benzophenone derivatives and thioxanthone derivatives.

The content of the photopolymerization initiator in the coating composition of the present invention is preferably 10 parts by weight or less based on 100 parts by weight of the component (a).

The method for obtaining the coating composition of the present invention is not particularly limited. For example, a dispersion of colloidal silica is mixed with a silane compound and, if necessary, water or a catalyst and reacted under the above-mentioned reaction conditions. The component (a) is mixed in the liquid after this reaction, and then the dispersion medium of the colloidal silica and the volatile matter generated by the hydrolysis reaction of the silane compound are removed, and then, if necessary, a photopolymerization initiator and other additives. Is particularly preferred.

The coating composition of the present invention is basically provided without containing an organic solvent, but may be provided with an organic solvent if necessary. As this organic solvent, one that can uniformly mix the component (a) and the photopolymerization initiator and can uniformly disperse the component (b) is used. It is suitable that the boiling point at normal pressure is 50 ° C. or more and 200 ° C. or less and the viscosity at normal temperature (25 ° C.) is 10 centipoise or less. Specifically, alcohols such as ethanol, isopropyl alcohol, normal propyl alcohol, normal butyl alcohol, and isobutyl alcohol; aromatic hydrocarbons such as benzene and toluene; ketones such as acetone and methyl ethyl ketone; ethers such as dioxane; Examples thereof include esters such as ethyl acetate and butyl acetate, N, N-dimethylformamide, and the like, and these organic solvents can be used alone or in combination of two or more.

Furthermore, in the coating composition of the present invention, various additives such as a surface smoothing agent, a surfactant, an ultraviolet absorber and a storage stabilizer can be appropriately added and used as necessary. .

Examples of methods for applying the coating composition to the surface of various molded articles include brush coating method, casting method, roller coating method, bar coating method, spray coating method, air knife coating method, dipping method and the like. Examples thereof include, but are not limited to. The coating amount of the coating composition on the surface of the molded article is preferably such that the cured film has a thickness of 1 to 30 μm. If the film thickness is less than 1 μm, abrasion resistance is poor, and if the film thickness exceeds 30 μm, cracks and the like tend to occur in the cured film, which is not preferable. By irradiating the coating film formed by such a method with active energy rays such as ultraviolet rays to cure it, a good cured film can be formed.

The molded products having a coating film formed on the surface thereof according to the present invention are various molded products which are required to have improved surface abrasion resistance and the like. In particular, a synthetic resin molded article is typically exemplified, for example, polymethylmethacrylate, a copolymer having methylmethacrylate as a main constituent, polystyrene, styrene-methylmethacrylate copolymer, styrene-acrylonitrile copolymer, polycarbonate, Preferred materials include cellulose acetate butyrate resin, polyacrylic diglycol carbonate resin, polyvinyl chloride resin, polyester resin, and the like.

[0049]

EXAMPLES The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the examples. In addition, the measurement and evaluation of various physical properties in the examples were performed by the methods described below.

1) Scratch resistance No. 000 steel wool was attached to a 25φ circular pad,
This pad was placed on the surface of a sample held on a reciprocating abrasion tester table, and reciprocally scratched 100 times under a load of 1000 g. After washing this sample, the haze value was measured with a haze meter. The steel wool scratch resistance (%) is represented by (haze value after scratch)-(haze value before scratch).

2) Wear resistance According to the Taber wear test method, CS-10F wear wheels and 50
A weight of 0 g was combined and the haze value after 100 rotations was measured with a haze meter. The haze value was measured at four locations around the orbit of the wear cycle, and the average value was calculated. The Taber abrasion resistance (%) is represented by (haze value after Taber test)-(haze value before Taber test).

3) Adhesion of coating film The sample was cut into 11 pieces in the vertical and horizontal directions at intervals of 1 mm with a razor blade to form 100 pieces of crevices, and a commercially available cellophane tape was closely adhered to the sample. When the film is rapidly peeled off, the number of cells (x) remaining without peeling off the film is indicated by x / 100.

4) Appearance Defects such as banding, spots, cracks, and cloudiness were visually judged and evaluated as follows. ○: No particular defects. × ... As a ΔYI value, occurrence of yellowish color of 4.0 or more, cracks, clouding and the like are observed.

5) Weather resistance Sunshine weather meter (Suga Test Instruments Co., Ltd. WE)
L-SUN-DC type) with a black panel temperature of 63
The appearance was evaluated after 2000 hours of exposure in a cycle of 12 minutes of rainfall at 48 ° C and 48 minutes of drying.

6) Water resistance After immersing the test piece in water at 80 ° C. for 25 days, the appearance,
The adhesion was evaluated.

<Example 1> 50 parts by weight of isopropyl alcohol-dispersed colloidal silica (silica content 30% by weight, manufactured by Catalysts & Chemicals Industries Co., Ltd., trade name OSCAL-1432) was added to N-phenyl-γ-aminopropyltrimethoxy. 5.6 parts by weight of silane (hereinafter abbreviated as PAPTS) and 1.5 parts by weight of deionized water were added, and the mixture was stirred at 40 ° C. for 1 hour.
Then, 45 parts by weight of 1,6-hexanediol diacrylate (hereinafter abbreviated as C6DA) was added, and all volatile components were distilled off under reduced pressure. Next, 1.8 parts by weight of trimethylbenzoyldiphenylphosphine oxide (hereinafter abbreviated as APO) and 0.7 parts by weight of benzophenone (hereinafter abbreviated as BNP) as a photopolymerization initiator, and 2- (2- Hydroxy-5-tert-butylphenyl) benzotriazole (hereinafter abbreviated as UA-1, manufactured by Ciba-Geigy, trade name Tinuvin-PS) 3.9
Part by weight was added and dissolved to obtain a coating composition.

This coating composition was applied to a polycarbonate plate (Mitsubishi Rayon Co., Ltd., trade name Dialite, thickness 1 m).
m) was applied, and a polyester film (manufactured by Dia foil Co., Ltd., thickness 50 μm) was applied thereon, and the mixture was tightly pressure-bonded using a sponge roll, and thoroughly squeezed so that the thickness of the applied film was about 7 μm. Then, the polyester film surface side is irradiated at a speed of 2 m / min under a 120 W / cm metal halide lamp (with a parallel reflector, an ozoneless type, a distance from the object to be irradiated is 30 cm) adjusted to an irradiation width of 13 cm. Was passed. Then, only the polyester film is peeled off, and further 120 W / cm
High-pressure mercury lamp (with parallel reflector, ozone type,
An irradiation width of 13 cm and a distance between the subject and the lamp of 30 cm) were passed at a speed of 2 m / min to obtain a resin plate whose surface was protected by a cured film of the coating composition. The hardness, adhesion, appearance, weather resistance and water resistance of this resin plate were evaluated according to the methods described above. The results are shown in Table 2.

<Examples 2 to 5 and Comparative Examples 1 and 2> Table 1
A coating composition having various compositions shown in Table 1 was prepared in the same manner as in Example 1, and the polycarbonate plate or the polymethylmethacrylate plate used in Example 1 (Mitsubishi Rayon Co., Ltd., trade name Acrylite, thickness 1 mm) was prepared. By applying and curing the above in the same manner as in Example 1, a resin plate whose surface was protected by a cured film was obtained. These resin plates were evaluated in the same manner as in Example 1. The results are shown in Table 2.

Example 6 To 30 parts by weight of the same colloidal silica as used in Example 1, 1.7 parts by weight of phenyltrimethoxysilane (hereinafter abbreviated as PTMS) and 0.8 parts by weight of deionized water were added. The mixture was stirred at 40 ° C for 1 hour.
Then, 30 parts by weight of C6DA and 20 parts of a condensate of trimethylolethane / acrylic acid / succinic acid (molar ratio 2/4/1) (hereinafter abbreviated as TAS) are added, and most of volatile components are distilled off under reduced pressure. did. Then, 1.7 parts by weight of γ-aminopropyltrimethoxysilane (hereinafter abbreviated as APTMS) was added, and the mixture was stirred at 40 ° C. for 1 hour. Then, the volatile matter was completely distilled off, and 1.7 parts by weight of APO, 0.6 parts by weight of BNP and 3.7 parts by weight of UA-1 were added to obtain a coating composition.

By curing this coating composition in the same manner as in Example 1, a resin plate whose surface was protected by a cured film was obtained. The evaluation results are shown in Table 2.

<Examples 7 and 8> A coating composition having the composition shown in Table 1 was prepared in the same manner as in Example 6, and the coating solution was cured in the same manner as in Example 1 to give a cured film. To obtain a resin plate whose surface was protected. The evaluation results are shown in Table 2.

Example 9 25 parts by weight of N, N-dimethyl-m-aminophenol, 37.4 parts by weight of γ-trimethoxysilylpropyl isocyanate and 0.02 part by weight of di-n-butyltin dilaurate were mixed. A viscous liquid was obtained by stirring at 60 C for 18 hours. The infrared absorption spectrum and ¹ H-NMR spectrum of the product show that the hydroxyl group and the isocyanate group have completely disappeared to form a carbamate bond, and N, N-dimethyl-m-aminophenyl represented by the following structural formula is shown. It was confirmed that -γ-trimethoxysilylpropyl carbamate was produced (hereinafter abbreviated as DMPTS).

[0063]

[Chemical 11] Using DMPTS as a silane compound, a coating solution was prepared and cured in the same manner as in Example 1 to obtain a resin plate whose surface was protected by a cured film. The composition of the coating liquid and the evaluation results of the resin plate are shown in Tables 1 and 2, respectively.

Example 10 PAPTS 11.2 was added to 100 parts by weight of the same colloidal silica as used in Example 1.
Parts by weight and 3 parts by weight of deionized water were added, and the mixture was stirred at 40 ° C. for 1 hour. Then, 40 parts by weight of bis (acryloyloxyethyl) hydroxyethyl isocyanurate (Aronix M-215, manufactured by Toagosei Co., Ltd.), 10 parts by weight of C6DA and 6 of isobutyl alcohol.
0 part by weight was added and well stirred. Next, 2.4 parts by weight of APO as a photopolymerization initiator and 0.
8 parts by weight and 5 parts by weight of UA-1 as an ultraviolet absorber were added and dissolved to obtain a coating composition.

Then, this coating composition was applied by dip coating to the same polycarbonate plate as used in Example 1 at a rate of 0.3 cm / sec to form a film, and the film was formed at room temperature in an atmosphere of 10
Let stand for a minute to evaporate the solvent. Then, irradiation was performed in the same manner as in Example 1 except that the polyester film was not covered, the distance between the subject and the lamp during irradiation with the high-pressure mercury lamp was 15 cm, and the passing speed was 1.5 m / min. A resin plate whose surface was protected by the cured film of 1. was obtained. This resin plate was also evaluated in the same manner as in Example 1.
The results are shown in Table 2.

[0066]

[Table 1] (Abbreviations in Table 1) THFA: Tetrahydrofurfuryl acrylate M-215: Bis (acryloyloxyethyl) hydroxyethyl isocyanurate (trade name Aronix M-215 manufactured by Toagosei Co., Ltd.) S-1: Isopropyl alcohol dispersion type Colloidal silica (silica content 30% by weight, manufactured by Catalyst Kasei Kogyo Co., Ltd., trade name OSCAL-1432) S-2: Water-dispersed colloidal silica (silica content 20% by weight, Nissan Chemical Industries, Ltd., trade name Snow) Tex O) DETX: 2,4-diethylthioxanthone MPG: methylphenylglyoxylate

[0067]

[Table 2] (Abbreviations in Table 2) PC: Polycarbonate PMMA: Polymethylmethacrylate

[0068]

The coating composition of the present invention can be applied without the use of a solvent, and the coating film formed by coating and curing the composition is excellent in abrasion resistance and scratch resistance and has a good appearance. Is. It also exhibits excellent weather resistance and water resistance, and is effective in preventing the occurrence of cracks in the film.

In addition, since the surface-coated molded article of the present invention has its surface covered with the above-mentioned cured compound film, for example, deterioration of aesthetics due to scratches, which has been a problem in the conventional synthetic resin molded articles, can be avoided. Can solve various problems.

[Procedure amendment]

[Submission date] August 5, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0064

[Correction method] Change

[Correction content]

Example 10 PAPTS 11.2 was added to 100 parts by weight of the same colloidal silica as used in Example 1.
Parts by weight and 3 parts by weight of deionized water were added, and the mixture was stirred at 40 ° C. for 1 hour. Then, 40 parts by weight of bis (acryloyloxyethyl) hydroxyethyl isocyanurate (Aronix M-215, manufactured by Toagosei Co., Ltd.), 10 parts by weight of C6DA and 6 of isobutyl alcohol.
0 part by weight was added and well stirred. Then, 0.8 parts by weight of APO as a photopolymerization initiator and methylphene were added thereto.
2.4 parts by weight of ruglioxylate and 5 parts by weight of UA-1 as an ultraviolet absorber were added and dissolved to obtain a coating composition.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Watanabe 20-1 Miyukicho, Otake City, Hiroshima Prefecture Mitsubishi Rayon Co., Ltd. Central Research Laboratory

Claims (2)

[Claims] 1. A crosslinkable polymerizable compound (a-1) having (a) at least two acryloyloxy groups and / or methacryloyloxy groups in the molecule, or 50% by weight of the crosslinkable polymerizable compound (a-1). A mixture of the above and the compound (a-2) copolymerizable therewith, (B) General formula (I) (in the formula, R ¹ and R ² are each independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms,
R ³ is a divalent hydrocarbon group having 1 to 10 carbon atoms which may have an ether bond and / or a carbonyl bond, R 3
⁴ is a divalent hydrocarbon group having 1 to 10 carbon atoms, R ⁵ is a hydrocarbon group having 1 to 3 carbon atoms, R ⁶ is a hydrogen atom or 1 to carbon atoms
10 hydrocarbon groups, m represents 0 or 1, and n represents an integer of 0 to 2). A coating composition comprising silica particles whose surface is modified with a hydrolyzate of a silane compound represented by and (c) a photopolymerization initiator. 2. A molded product whose surface is coated with the cured product of the coating composition according to claim 1.