JPH06299088A - Coating composition and surface-coated molding - Google Patents

Abstract

PURPOSE:To obtain a coating composition which can be applied without using any solvent and can give a cured coating film excellent in abrasion, scratch, weather and water resistances, etc., by mixing a cross-linking-polymerizable compound having (meth)acryloyloxy groups with silica particles surface-modified with a hydrolyzate of an alkoxy compound. CONSTITUTION:The composition comprises a cross-linking-polymerizable compound having at least two acryloyloxy groups and/or methacryloyloxy groups in the molecule or a mixture comprising at least 50 pts.wt. this compound and a compound copolymerizable therewith and silica particles surface-modified with a hydrolyzate of an alkoxysilane compound having a functional group which can generate a free radical when irradiated with an actinic radiation. The term 'surface-modified with a hydrolyzate' means that a hydrolyzate of a silane compound is held on at least part of the surface of a silica particle, so that the surface properties of this particle are improved.

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.

[0006]

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.

[0007]

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,
And (b) a coating composition comprising silica particles whose surface is modified with a hydrolyzate of an alkoxysilane compound having a functional group that generates a free radical upon irradiation with an active energy ray. Another aspect of the present invention is an article whose surface is coated with a cured product of such a coating composition.

[0008]

In the coating composition of the present invention, the surface of the silica particles (b) is modified with a hydrolyzate of an alkoxysilane compound having a functional group that produces a free radical upon irradiation with active energy rays. The silica particles (b) can be dispersed in the component (a) at a high concentration, and the above objects such as improvement of abrasion resistance can be achieved. Furthermore, irradiation of active energy rays causes free radicals to be generated on the surface of the silica particles, causing polymerization of the component (a), so that the polymer of the component (a) is firmly bonded to the silica surface, and a cured coating film is obtained. Will develop a 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.

A 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 (meth) acryloyloxy, and may have an ether bond, a thioether bond, an ester bond, an amide bond, a urethane bond or the like in its molecule.

Examples of the crosslinkable polymerizable compound (a-1) include ester compounds obtained from polyhydric alcohols and (meth) acrylic acid or their derivatives, or polyhydric alcohols and polycarboxylic acids and (meth) acrylics. 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 (I)

[0014]

[Chemical 1] (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 (I) 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 (I) include diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate and 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.

An ester compound obtained from a polyhydric alcohol, a polyvalent carboxylic acid, and (meth) acrylic acid or a derivative thereof 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) include 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 (II)

[0022]

[Chemical 2] (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 described above. As the copolymerizable compound (a-2), for example, a compound having one (meth) acryloyloxy 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, 2,3,3-tetrafluoropropyl (meth) acrylate, 1H, 1H,
5H-octafluoropentyl (meth) acrylate,
N-hydroxybutyl (meth) acrylamide, hydroxymethyl diacetone (meth) acrylamide, N-hydroxyethyl-N-methyl (meth) acrylamide,
The following general formula (III) or (IV)

[0024]

[Chemical 3]

[0025]

[Chemical 4] (In the general formulas III and IV, 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 (III) or (IV) include methoxydiethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate and 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 a silica particle whose surface is coated with a hydrolyzate of a silane compound having a functional group that generates a free radical upon irradiation with an active energy ray. Here, the active energy ray refers to an electromagnetic wave (more specifically, one having a wavelength of 200 to 500 nm) in an area mainly in the ultraviolet region and partially including visible light, and a free radical is generated by irradiation with the active energy ray. The functional group (hereinafter, abbreviated as “radical-generating functional group”) to be used typically includes, but is not limited to, a benzoyl group, a thiuram sulfide group, an azo group, and a peroxide group. . Further, “the surface is modified with a hydrolyzate” means that the hydrolyzate of the silane compound is retained on a part or all of the surface of the silica particle, and thereby the surface characteristics are modified. Means 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, for example, 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.

As a method for obtaining a silane compound having a radical-forming functional group used in the present invention, (i) a radical-forming functional group and at least one group of a hydroxyl group, an amino group and a carboxyl group (hereinafter referred to as a reactive group) ) And an alkoxysilane compound having an isocyanate group by reacting the reactive group with the isocyanate group, (ii) having both a radical-forming functional group and a reactive group A compound and a method obtained by an esterification reaction of an alkoxysilane compound having a carboxyl group or a glycidyl group, (iii) a method obtained by a Friedel-Crafts reaction of benzoyl chloride and phenyltrialkoxysilane, and the like. i)
The method obtained by reacting the compound having both a radical-forming functional group and a reactive group with an alkoxysilane compound having an isocyanate group is preferable in that the reaction can be carried out under mild conditions.

Examples of the compound having both a radical-generating functional group and a reactive group include 2-hydroxybenzophenone, 4-hydroxybenzophenone, 2-aminobenzophenone, 4-aminobenzophenone, 2-benzoylbenzoic acid and 4-benzoylbenzoic acid. Acid, benzoin, 2-
Hydroxy-2-methyl-1-phenylpropane-1-
On, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 4- (2 -Hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxythioxanthone and the like and mixtures thereof can be mentioned.

As the alkoxysilane compound having an isocyanate group, OCN (CH ₂ ) ₃ Si (O
_{CH 3) 3, OCN (CH} 2) 3 Si (OC 2 H 5)
₃ , OCN (CH ₂ ) ₃ Si (OCH ₃ ) ₂ CH ₃ , O
_{CN (CH 2) 3 Si (} OC 2 H 5) 2 CH 3 and the like, and mixtures thereof.

Component (b) in the coating composition of the present invention
To obtain the above, only a silane compound having a radical-forming functional group 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, and tetra n-.
Butoxysilane, tetrahexyl orthosilicate, tetraphenyl orthosilicate, tetrabenzyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyl Examples thereof include dimethoxysilane, diphenyldimethoxysilane, methylethyldiethoxysilane, methylphenyldimethoxysilane, methoxyethyltriethoxysilane 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.

In the coating composition of the present invention, a photopolymerization initiator can be used in order to completely cure the composition by irradiation with active energy rays. The photopolymerization initiator is not particularly limited as long as it can cause the polymerization reaction of the component (a). Specific examples include carbonyl compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, acetoin, butyroin, toluoin, benzyl, benzophenone, p-methoxybenzophenone; tetramethylthiuram monosulfide, tetra Sulfur compounds such as methyl thiuram disulfide; Azo compounds such as azobisisobutyronitrile and azobis-2,4-dimethylvaleronitrile;
Examples thereof include peroxide compounds such as benzoyl peroxide and ditertiary 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 blending amount of the photopolymerization initiator is preferably 10 parts by weight or less with respect to 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 an organic solvent, but may be provided with an organic solvent (c) if necessary.
As the organic solvent (c), a solvent that can uniformly mix the component (a) and the photopolymerization initiator and can uniformly disperse the component (b) is used. Boiling point at atmospheric pressure is 50 ° C or higher 20
It is suitable that the temperature is 0 ° C. or lower and the viscosity at room temperature (25 ° C.) is 10 centipoise or lower. 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, if 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.

[0043]

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) Abrasion resistance According to the Taber abrasion test method, CS-10F abrasion 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 with a razor blade at intervals of 1 mm to make 11 cuts in each length and width to make 100 goggles, and a commercially available cellophane tape was adhered well, and then 90 ° front direction 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 determined 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.

Reference Example Synthesis of an alkoxysilane compound having a functional group which produces a free radical upon irradiation with active energy rays: 4-hydroxybenzophenone 9
9.1 parts by weight, 10-2.5 parts by weight of 3- (trimethoxysilylpropyl) isocyanate, 200 parts by weight of benzene and 0.1 part by weight of di-n-butyltin disurate were mixed and stirred at 50 ° C. for 40 hours. Then, the solvent in the reaction product was completely distilled off under vacuum to obtain a viscous liquid.
It was confirmed from the infrared absorption spectrum and ¹ H-NMR spectrum of the product that the hydroxyl group and the isocyanate group had completely disappeared, and a carbamate bond had been formed, and the compound having the following structure (hereinafter, silane compound (1) Has been generated).

[0051]

[Chemical 5] In the same manner as above, benzoin, 2-hydroxy-2-
Methyl-1-phenylpropan-1-one (manufactured by Merck, trade name Darocur 1173) or 1-hydroxycyclohexyl phenyl ketone (manufactured by Ciba-Geigy, trade name Irgacure 184) and 3- (trimethoxysilylpropyl) isocyanate Depending on the reaction, compounds having the following structures (hereinafter, silane compound (2),
(3) and (4) are obtained).

[0052]

[Chemical 6]

[0053]

[Chemical 7]

[0054]

[Chemical 8] <Example 1> Isopropyl alcohol-dispersed colloidal silica (silica content 30% by weight, Catalyst Kasei Kogyo Co., Ltd.)
Manufactured by the trade name OSCAL-1432), 5.6 parts by weight of silane compound (1) synthesized in Reference Example, 0.0
1.5 parts by weight of 1N aqueous hydrochloric acid solution was added, and the mixture was stirred at 40 ° C. for 1 hour. Thereafter, 45 parts by weight of 1,6-hexanediol diacrylate (hereinafter abbreviated as C6DA) was added,
All volatile components were distilled off under reduced pressure. Then, 2- (2-hydroxy-5-tert-) as an ultraviolet absorber is added to this.
Butylphenyl) benzotriazole (hereinafter referred to as UA-1
Abbreviated as Ciba Geigy, trade name Tinuvin-PS)
3.9 parts by weight was added and dissolved to obtain a coating composition.

A polycarbonate plate (manufactured by Mitsubishi Rayon Co., 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.

<Example 2> 50 parts by weight of the same colloidal silica as used in Example 1 was mixed with silane compound (1) 5.
6 parts by weight and 1.5 parts by weight of 0.01 N hydrochloric acid aqueous solution were added, and the mixture was stirred at 40 ° C. for 1 hour. After that, C6DA 35
Parts by weight and 15 parts by weight of a trimethylolethane / acrylic acid / succinic acid (molar ratio 2/4/1) condensate (hereinafter abbreviated as TAS) were added, and all volatile components were distilled off under reduced pressure. Next, trimethylbenzoyldiphenylphosphine oxide (hereinafter, referred to as APO) as a photopolymerization initiator
1.8 parts by weight and benzophenone (hereinafter, BN)
(Abbreviated as P) 0.7 parts by weight, UA-1 as an ultraviolet absorber
3.9 parts by weight was added and dissolved to obtain a coating composition.

This coating composition was used as a coating solution and applied on a polycarbonate plate in the same manner as in Example 1 and cured to obtain a resin plate whose surface was protected by a cured film. This resin plate was also evaluated in the same manner as in Example 1. The results are shown in Table 2.

<Examples 3 to 9 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 10> 100 parts by weight of the same colloidal silica as used in Example 1 was added to the silane compound (1).
11.2 parts by weight and 3 parts by weight of 0.01 N hydrochloric acid aqueous solution were added, and the mixture was stirred at 40 ° C. for 1 hour. Then, bis (acryloyloxyethyl) hydroxyethyl isocyanurate (trade name, Aronix M-21, manufactured by Toagosei Co., Ltd.)
5) 40 parts by weight, 10 parts by weight of C6DA, and 60 parts by weight of isobutyl alcohol were added and well stirred. Next, 0.8 parts by weight of APO as a photopolymerization initiator and 2.4 parts by weight of methylphenylglyoxylate (hereinafter abbreviated as MPG), and 5 parts by weight of UA-1 as an ultraviolet absorber were added and dissolved therein. To obtain a coating composition.

Then, this coating composition was applied by dip coating to a polycarbonate plate similar to that used in Example 1 at a rate of 0.3 cm / sec to form a coating film, which was then applied in an atmosphere at room temperature for 10 minutes.
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.

[0061]

[Table 1] (Abbreviations in Table 1) C6DA: 1,6-hexanediol diacrylate TAS: Condensate of trimethylolethane / acrylic acid / succinic acid (molar ratio 2/4/1) FA731A: tris (acryloyloxy) isocyanurate ( Hitachi Chemical Co., Ltd., trade name FA-731A) THFA: Tetrahydrofurfuryl acrylate M-215: Bis (acryloyloxyethyl) hydroxyethyl isocyanurate (Toagosei Co., Ltd. trade name, Aronix M-215) S- 1: Isopropyl alcohol-dispersed 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. ), Product name Snowtex O) PTMS: Phenyl Tol Tokishishiran

[0062]

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

[0063]

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, is caused. Can solve various problems.

 ─────────────────────────────────────────────────── ─── 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). The surface is modified with a mixture of the above and a compound (a-2) copolymerizable therewith, and (b) a hydrolyzate of an alkoxysilane compound having a functional group that generates a free radical upon irradiation with an active energy ray. A coating composition comprising silica particles. 2. A molded product whose surface is coated with the cured product of the coating composition according to claim 1.