JP3179932B2 - Coating composition and surface-coated molding - Google Patents

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 irradiating active energy rays, and a cured film of the coating composition. The present invention relates to a surface-coated molded product such as a synthetic resin molded product coated with a resin.

[0002]

2. Description of the Related Art In recent years, it has been widely used to use a transparent plastic material having high crush resistance as an alternative to a transparent plate glass. However, transparent plastic materials have the serious drawback of being softer than glass and more susceptible to surface wear and scratching.

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

On the other hand, in order to impart a higher surface hardness to a molded article, for example, Japanese Patent Application Laid-Open Nos.
A method in which an alkoxysilane compound as disclosed in JP-A-9-64671 or the like is applied to the surface of a plastic molded product and cured by heat, or disclosed in JP-A-56-106969.
Japanese Patent Application Laid-Open No. Hei 2-272204 discloses a method in which a mixture of colloidal silica and an organic resin is applied to the surface of a plastic molded product and cured by heat. However, these methods require a drying step due to the use of a solvent, which tends to cause a problem in the appearance of the coated molded article, and require a large amount of energy consumption due to the need for curing by heat. It is industrially disadvantageous because it requires a long time. Furthermore, drying using a solvent is not preferable from the viewpoint of global environmental protection, which has been particularly noted in recent years.

On the other hand, Japanese Patent Publication No. 1-55307 and 3
JP-A-2168, JP-A-3-6190, 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 or methacryl group, and a polyfunctional acrylate. It has been disclosed. These can be used in the absence of a solvent if necessary, and can impart considerably excellent surface hardness to a plastic molded product.However, because of the hydrophilic properties derived from the structure of the acryl group or methacryl group in the alkoxysilane compound, The interface between the colloidal silica and the alkoxysilane in the coating was susceptible to hydrolysis, resulting in impaired weather resistance and water resistance of the coating.

[0006]

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

[0007]

The present invention relates to (a) a cross-linkable polymerizable compound (a) having at least two acryloyloxy groups and / or methacryloyloxy groups in a molecule;
-1) or a mixture comprising at least 50% by weight of the crosslinkable polymerizable 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 free radicals upon irradiation with active energy rays. Another aspect of the present invention is an article having a surface coated with a cured product of the 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 capable of generating free radicals upon irradiation with active energy rays. In addition, the silica particles (b) can be dispersed at a high concentration in the component (a), and the above object such as improvement of abrasion resistance can be achieved. Furthermore, irradiation with active energy rays generates free radicals on the surface of the silica particles and causes polymerization of the component (a). Therefore, the polymer of the component (a) is firmly bonded to the silica surface, and the cured film is formed. Will exhibit high surface hardness. More remarkably, the coating composition of the present invention can improve the weather resistance and water resistance of a coating film which has been a problem in the prior art.

Hereinafter, the present invention will be described in detail.

Component (a) in the coating composition of the present invention
Are cross-linked polymerizable compounds having at least two acryloyloxy groups and / or methacryloyloxy groups (hereinafter abbreviated as (meth) acryloyloxy groups) in the molecule.
(a-1). This component (a) is composed of at least 50% by weight of a crosslinkable polymerizable compound (a-1) and a compound (a) copolymerizable therewith.
-2).

A crosslinked polymerizable compound (a-1) having at least two (meth) acryloyloxy groups in the molecule
Is a group in which the residue other than (meth) acryloyloxy is a hydrocarbon or a derivative thereof, and the molecule may contain an ether bond, a thioether bond, an ester bond, an amide bond, a urethane bond, or the like.

As the crosslinkable polymerizable 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 An ester compound obtained from an acid or a derivative thereof is exemplified. Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and having 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 (that is, 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 Trihydric alcohols such as 1,2,6-hexanetriol; and others , Pentaerythritol (ie, 2,
2-bis (hydroxymethyl) -1,3-propanediol), diglycerol, dipentaerythritol and the like.

Examples of the crosslinkable polymerizable compound (a-1) obtained as a polyhydric alcohol poly (meth) acrylate include:
The following general formula (I)

[0014]

Embedded image (In the formula, n represents an integer of 0 to 4, and four or more Xs in the molecule, two or more of which represent a (meth) acryloyloxy group, and the rest each independently represent a hydrogen atom or a hydroxyl group. , An amino group, an alkyl group or a substituted alkyl group.).

As the compound represented by the general formula (I), specifically, 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, tripentaerythritol penta (meth) acrylate,
Examples thereof include tripentaerythritol hexa (meth) acrylate and tripentaerythritol hepta (meth) acrylate.

Examples of poly (meth) acrylates of polyhydric alcohols other than the compounds of the above general formula (I) include, for example, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate and tetraethylene glycol di (meth) acrylate. ) Acrylate, 1,4-
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 preferred 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 And dipentaglycerol pentaacrylate.

An ester compound obtained from a polyhydric alcohol, a polycarboxylic 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. By reacting a mixture such that the hydroxyl groups of the above and the carboxyl groups of both the polyvalent carboxylic acid and the (meth) acrylic acid are finally equivalent. Among these ester compounds, preferred are polyhydric alcohols such as dihydric alcohols, trihydric alcohols, and mixtures of dihydric alcohols and trihydric alcohols. And esterified products obtained using the above. When a mixture of a trihydric alcohol and a dihydric alcohol is used, the molar ratio between the trihydric alcohol and the dihydric alcohol may be arbitrarily selected. The molar ratio of the dicarboxylic acid and the (meth) acrylic acid when used together is such that the carboxyl group of the dicarboxylic acid is 2 mol or less per 1 mol of the carboxyl group of (meth) acrylic acid. Is preferred. If the divalent carboxylic acid is in excess of the above range, the resulting ester may have an excessively high viscosity, making it difficult to form a coating film.

Examples of the divalent carboxylic acid or a derivative thereof used in the synthesis of the above 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, aromatic dicarboxylic acids such as terephthalic acid; other thioglycolic acid, thiodivalic acid,
Diglycolic acid, maleic acid, fumaric acid, itaconic acid,
And their chlorides, anhydrides and esters.

Specific examples of the above ester compounds used as the crosslinkable polymerizable compound (a-1) include malonic acid / trimethylolethane / (meth) acrylic acid, malonic acid / trimethylolpropane / (meth) acrylic acid, 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 / pentane 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 by a combination of compounds such as (meth) acrylic acid, maleic anhydride / trimethylolethane / (meth) acrylic acid, and maleic anhydride / glycerin / (meth) acrylic acid.

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

[0022]

Embedded image (Wherein R is each independently hexamethylene diisocyanate, tolylene diisocyanate, diphenylethane diisocyanate, xylene diisocyanate, 4,4 ′
-Represents the residue of methylene bis (cyclohexyl isocyanate), isophorone diisocyanate or trimethylhexamethylene diisocyanate. ) And an acrylic monomer having active hydrogen (eg, 2-hydroxyethyl (meth) acrylate, 2-hydroxy-3-methoxypropyl (meth) acrylate, N-methylol (meth) Acrylamide, N-hydroxy (meth) acrylamide, etc.)
And urethane (meth) acrylate obtained by reacting 1 mol or more of an acrylic monomer per 1 mol of isocyanate group by a conventional method; poly [such as tri (meth) acrylate of 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 polymerizable 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, ethyl carbitol (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]

Embedded image

[0025]

Embedded image (In the general formulas III and IV, n represents 1 to 10, X represents a (meth) acryloyloxy group, and R represents an alkyl group, a substituted alkyl group, a phenyl group, a substituted phenyl group, a benzyl group or a substituted benzyl group. Mono) (meth) acrylate represented by the following formula:

The mono (meth) acrylate represented by the general formula (III) or (IV) includes, for example, methoxydiethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, butoxyethylene Glycol (meth) acrylate and the like.

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 and urethane (meth) acrylates.

Component (b) in the coating composition of the present invention
Are silica particles whose surface is coated with a hydrolyzate of a silane compound having a functional group that generates free radicals upon irradiation with active energy rays. Here, the active energy ray refers to an electromagnetic wave (more specifically, a wavelength of 200 to 500 nm) in a region including the ultraviolet region and partially including visible light, and generates free radicals by irradiation with the active energy beam. Typical functional groups (hereinafter abbreviated as "radical generating functional group") include, but are not limited to, benzoyl group, thiuram sulfide group, azo group, peroxide group and the like. . Further, "the surface has been modified with a hydrolyzate" means that the hydrolyzate of the silane compound is held on a part or the whole of the surface of the silica particles, and the surface characteristics are thereby modified. Means In addition, the silica particles in which the condensation reaction of the hydrolyzate has progressed are also included. Typically, this surface modification in the present invention can be easily performed by hydrolyzing a silane compound in the presence of silica particles, or by causing a hydrolysis and condensation reaction.

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

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

Compounds having both a radical-forming functional group and a reactive group include 2-hydroxybenzophenone, 4-hydroxybenzophenone, 2-aminobenzophenone, 4-aminobenzophenone, 2-benzoylbenzoic acid, and 4-benzoylbenzoate. 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 Examples thereof include -hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexylphenylketone, 2-hydroxythioxanthone, and the like, and mixtures thereof.

As an 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 mixtures thereof can be mentioned.

Component (b) in the coating composition of the present invention
In order 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 co-hydrolyzed and condensed with another silane compound. Such other silane compounds include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetra-i-propoxysilane, tetra-n-
Butoxysilane, tetrahexyl orthosilicate, tetraphenylorthosilicate, tetrabenzylorthosilicate, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyl Examples include dimethoxysilane, diphenyldimethoxysilane, methylethyldiethoxysilane, methylphenyldimethoxysilane, methoxyethyltriethoxysilane, and trimethylmethoxysilane.

When colloidal silica is used as the silica particles, the silane compound is mixed into a dispersion of colloidal silica and hydrolyzed with water in the system or newly added water, whereby the surface is modified with the hydrolyzate. The obtained silica particles (b) are obtained. As a catalyst for performing the hydrolysis reaction 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, and the like.
Phosphoric acid or the like is used. Organic acids include formic acid, acetic acid,
Oxalic acid, acrylic acid, methacrylic acid and the like can be mentioned.

In the hydrolysis reaction system of the silane compound, a solvent can be used in order to carry out the reaction mildly and uniformly. The solvent is desirably one that can make the silane alkoxide, which is a reactant, water and a catalyst compatible. Specific examples include water; alcohols such as methanol, ethanol, and isopropyl alcohol; ketones such as acetone and methyl isobutyl ketone; and ethers such as tetrahydrofuran and dioxane. As the solvent, the above-described dispersion medium of colloidal silica may be used as it is, or may be newly added in a necessary amount. The amount of the solvent to be used is not particularly limited as long as the reactant can be uniformly dissolved, but if the concentration of the reactant is too low, the reaction rate may be significantly reduced. The hydrolysis and condensation reaction of the silane compound is carried out at a temperature of about room temperature to about 120 ° C. for 30 minutes to 24 hours.
The reaction is carried out for about 1 hour, preferably at about room temperature to about the boiling point of the solvent for about 1 to 10 hours.

The blending ratio in component (b) is not particularly limited, but the silane compound is preferably 5-200 parts by weight, more preferably 25-200 parts by weight, per 100 parts by weight of silica particles (solid content in the case of colloidal silica). Use 100 parts by weight. The mixing ratio of the component (a) and the component (b) is not particularly limited, either, but 100 parts by weight of the silica particles (solid content in the case of colloidal silica) in the component (b)
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 may 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 a 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, and p-methoxybenzophenone; tetramethylthiuram monosulfide, Sulfur compounds such as methylthiuram disulfide; azo compounds such as azobisisobutyronitrile and azobis-2,4-dimethylvaleronitrile;
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 amount of the photopolymerization initiator 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 silane compound and, if necessary, water or a catalyst are mixed with a dispersion of colloidal silica and reacted under the above-described reaction conditions. The component (a) is mixed into the liquid after the reaction, and then a dispersion medium of colloidal silica and volatile components generated by a hydrolysis reaction of the silane compound are removed. Then, if necessary, a photopolymerization initiator and other additives are added. Is particularly preferred.

The coating composition of the present invention is basically provided as containing no organic solvent, but may be provided as containing an organic solvent (c) if necessary.
As the organic solvent (c), a solvent that can be uniformly mixed with the component (a) and the photopolymerization initiator and that can uniformly disperse the component (b) is used. Boiling point at normal pressure is 50 ° C or more and 20
Suitable are those having a viscosity of 0 ° C. or less and a viscosity at room temperature (25 ° C.) of 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; 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.

Further, 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 the method of applying the coating composition to the surface of various molded articles include a brush coating method, a casting method, a roller coating method, a bar coating method, a spray coating method, an air knife coating method, a dipping method and the like. Although it is mentioned, it is not particularly limited. The amount of the coating composition to be applied to the surface of the molded article is suitably applied so that the film thickness after curing becomes 1 to 30 μm. When the film thickness is less than 1 μm, the abrasion resistance is poor, and when the film thickness exceeds 30 μm, cracks and the like tend to easily 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 and curing the coating film, a good cured coating film can be formed.

The molded articles having a film formed on the surface according to the present invention are various molded articles which are required to have improved surface abrasion resistance and the like. In particular, typical examples include molded products made of synthetic resins, such as polymethyl methacrylate, a copolymer having methyl methacrylate as a main component, polystyrene, styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer, polycarbonate, Preferred materials include cellulose acetate butyrate resin, polyacryl diglycol carbonate resin, polyvinyl chloride resin, and polyester resin.

[0043]

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

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

2) Abrasion resistance According to the Taber abrasion test method, CS-10F wear wheels and 50
The haze value was measured with a haze meter when the weights of 0 g were combined and rotated 100 times. The haze value was measured at four points around the orbit of the wear cycle, and the average value was calculated. The Taber abrasion (%) is represented by (haze value after Taber test)-(haze value before Taber test).

3) Adhesion of the coating film The sample was cut with a razor blade at intervals of 1 mm at intervals of 11 mm in length and width to make 100 gobangs, and after adhering a commercially available cellophane tape, it was turned forward by 90 °. The number of squares (x) remaining without peeling off the film when the film is rapidly peeled off is indicated by x / 100.

4) Appearance Defects such as banding, spots, cracks, and cloudiness were visually determined and evaluated as follows. …: No noticeable defect. X: Yellowish color or a crack, clouding, or the like having a ΔYI value of 4.0 or more is observed.

5) Weather resistance Sunshine weather meter (WE, Suga Test Instruments Co., Ltd.)
L-SUN-DC type) and black panel temperature 63
After exposure for 2,000 hours at a cycle of rainfall at 12 ° C for 12 minutes and drying for 48 minutes, the appearance was evaluated.

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

Reference Example Synthesis of an alkoxysilane compound having a functional group that generates a free radical upon irradiation with an active energy ray: 4-hydroxybenzophenone 9
9.1 parts by weight, 102.5 parts by weight of 3- (trimethoxysilylpropyl) isocyanate, 200 parts by weight of benzene, and 0.1 part by weight of di-n-butyltin disulfate were mixed and stirred at 50 ° C. for 40 hours. Thereafter, the solvent in the reaction product was completely distilled off under vacuum to obtain a viscous liquid.
From the infrared absorption spectrum and ¹ H-NMR spectrum of the product, it was confirmed that the hydroxyl group and the isocyanate group had completely disappeared, and a carbamate bond had been formed, and a compound having the following structure (hereinafter referred to as a silane compound (1)) Abbreviated) was generated.

[0051]

Embedded image In the same manner as above, benzoin, 2-hydroxy-2-
Methyl-1-phenylpropan-1-one (manufactured by Merck, trade name Darocure 1173) or 1-hydroxycyclohexylphenyl ketone (manufactured by Ciba Geigy, trade name Irgacure 184) and 3- (trimethoxysilylpropyl) isocyanate By the reaction, compounds having the following structures (hereinafter, silane compound (2),
(Abbreviated as (3) and (4)).

[0052]

Embedded image

[0053]

Embedded image

[0054]

Embedded image <Example 1> Isopropyl alcohol-dispersed colloidal silica (silica content 30% by weight, Catalyst Chemical Industry Co., Ltd.)
5.6 parts by weight of a silane compound (1) synthesized in Reference Example,
1.5 parts by weight of a 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-) was added thereto as an ultraviolet absorber.
Butylphenyl) benzotriazole (hereinafter UA-1)
Abbreviation, Ciba Geigy Co., trade name Tinuvin-PS)
3.9 parts by weight were added and dissolved to obtain a coating composition.

This coating composition was coated on a polycarbonate plate (manufactured by Mitsubishi Rayon Co., Ltd., trade name: Dialite, thickness: 1 m).
m), and tightly pressed with a sponge roll while covering with a polyester film (manufactured by Diafoil Co., Ltd., thickness: 50 μm), and squeezed so that the thickness of the coating film became about 7 μm. Next, 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 ozone-less type, a distance to an object to be projected of 30 cm) adjusted to an irradiation width of 13 cm. Passed. Next, only the polyester film was peeled off, and further 120 W / cm
High pressure mercury lamp (with parallel reflector, ozone type,
It passed under an irradiation width of 13 cm and a distance of 30 cm between the object and the lamp 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. Table 2 shows the results.

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

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

<Examples 3 to 9 and Comparative Examples 1 and 2> Table 1
Were prepared by the same method as in Example 1, and the polycarbonate plate or the polymethyl methacrylate plate (manufactured by Mitsubishi Rayon Co., Ltd., trade name: acrylite, thickness 1 mm) used in Example 1 was prepared. By applying and curing 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. Table 2 shows the results.

Example 10 A silane compound (1) was added to 100 parts by weight of the same colloidal silica as used in Example 1.
11.2 parts by weight and 3 parts by weight of a 0.01 N hydrochloric acid aqueous solution were added, and the mixture was stirred at 40 ° C. for 1 hour. Thereafter, 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 the mixture was stirred well. Next, 0.8 parts by weight of APO as a photopolymerization initiator, 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 give a coating composition.

Next, this coating composition was applied to the same polycarbonate plate as used in Example 1 by dip coating at a rate of 0.3 cm / sec to form a coating film.
Allowed for minutes to evaporate the solvent. Then, irradiation was carried out in the same manner as in Example 1 except that the polyester film was not covered, the distance between the object 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 was obtained. This resin plate was evaluated in the same manner as in Example 1.
Table 2 shows the results.

[0061]

[Table 1] (Abbreviations in Table 1) C6DA: 1,6-hexanediol diacrylate TAS: Trimethylolethane / acrylic acid / succinic acid (molar ratio 2/4/1) condensate FA731A: Tris (acryloyloxy) isocyanurate ( TFA: Tetrahydrofurfuryl acrylate M-215: Bis (acryloyloxyethyl) hydroxyethyl isocyanurate (Toagosei Co., Ltd., trade name ARONIX M-215) manufactured by Hitachi Chemical Co., Ltd. S- 1: Colloidal silica dispersed with isopropyl alcohol (silica content 30% by weight, trade name OSCAL-1432, manufactured by Kasei Kagaku Co., Ltd.) S-2: Water-dispersed colloidal silica (silica content 20% by weight, Nissan Chemical Industries, Ltd.) ) Made, trade name Snowtex O) PTMS: phenyl tri Tokishishiran

[0062]

[Table 2] (Abbreviations in Table 2) PC: polycarbonate PMMA: polymethyl methacrylate

[0063]

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

Further, since the surface-coated molded article of the present invention has its surface covered with the above-mentioned cured multi-layered film, for example, a synthetic resin molded article has a problem such as a decrease in aesthetics due to scratches which has been a problem in the past. Various problems can be solved.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Watanabe 20-1 Miyukicho, Otake City, Hiroshima Prefecture Mitsubishi Rayon Co., Ltd. Central Research Laboratory (56) References Patent 3025587 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) C09D 4/00

Claims (2)

(57) [Claims] (1) 50% by weight of a crosslinked polymerizable compound (a-1) having at least two acryloyloxy groups and / or methacryloyloxy groups in a molecule, or the crosslinked 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 free radicals by irradiation with active energy rays. Coating composition comprising silica particles. 2. A molded article having a surface coated with a cured product of the coating composition according to claim 1.