JP3187603B2 - 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.

Further, Japanese Patent Application Laid-Open No. 3-56514 discloses that
A coating composition comprising a polyfunctional acrylate partially modified with an aminoorganofunctional silane and colloidal silica is disclosed. According to the disclosure, in the sense that a compound having both an acryl group and an alkoxysilyl group obtained by Michael addition of an aminoorganofunctional silane to a part of a double bond in a polyfunctional acrylate is used. As described above, colloidal silica, and alkoxysilane having an acrylic group or a methacryl group,
It is considered analogous to a coating composition comprising a multifunctional acrylate.

[0007]

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.

[0008]

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,

[0009]

Embedded image (B) general formula (I) wherein 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;
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 the surface of which is modified with a hydrolyzate of a silane compound represented by formula (1) and (c) a photopolymerization initiator. Another aspect of the present 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 object such as improvement of abrasion resistance can be achieved. Furthermore, the silane compound represented by the general formula (I) has a hydrogen bonded to carbon adjacent to a nitrogen atom and thus 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 by irradiation with active energy rays.

[0011]

Embedded image Further, hydrogen bonded to carbon adjacent to a nitrogen atom in the silane compound represented by the general formula (I) is also extracted by a radical that grows during polymerization, and generates a restartable radical there.

For these reasons, the irradiation of the active energy ray generates radicals in the silane compound represented by the general formula (I) bonded to the surface of the silica particles, causing polymerization of the component (a). The polymer of the component (a) is firmly bonded to the silica surface, and the cured film exhibits a 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).

Crosslinked polymerizable compound (a-1) having at least two (meth) acryloyloxy groups in the molecule
Is a group in which the residue other than the (meth) acryloyloxy group 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 (II)

[0018]

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.).

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, 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 compound of the general formula (II) 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 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, 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, malonic 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 cross-linkable polymerizable compound (a-1), for example, trimethylolpropane toluylene triisocyanate represented by the following general formula (III)

[0026]

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 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, 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, hydroxymethyldiacetone (meth) acrylamide, N-hydroxyethyl-
N-methyl (meth) acrylamide, the following general formula (IV)
Or (V)

[0028]

Embedded image

[0029]

Embedded image (In the general formulas IV and V, 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 (IV) or (V) 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 modified with a hydrolyzate of a silane compound represented by the general formula (I). Here, "the surface is modified with the 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 thereby the surface characteristics are modified. Means that. 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.

As the silane compound represented by the general formula (I) used in the present invention, for example, H ₂ NC ₃ H ₆ Si (O
CH ₃ ) ₃ , H ₂ NC ₃ H ₆ Si (OC ₂ H ₅ ) ₃ ,

[0035]

Embedded image CH ₃ NHC ₃ H ₆ Si (OCH ₃ ) ₃ , C ₂ H ₅ NH
C ₃ H ₆ Si (OCH ₃ ) ₃ ,

[0036]

Embedded image H ₂ NC ₂ H ₄ NHC ₃ H ₆ Si (OCH ₃ ) ₃ ,

[0037]

Embedded image 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 co-hydrolyzed and condensed with another silane compound. Such other silane compounds include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetra-i-propoxysilane, tetra-n-butoxysilane, tetrahexylorthosilicate, tetraphenylorthosilicate, tetrabenzylorthosilicate, methyl Trimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, diphenyldimethoxysilane, methylethyldiethoxysilane, methylphenyldimethoxysilane, methoxymethyl Ethyl triethoxy silane, trimethyl methoxy silane and the like can be mentioned.

When colloidal silica is used as the silica particles, the silane compound is mixed in 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 mixing ratio in the 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 the 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.

The photopolymerization initiator (c) in the coating composition of the present invention is capable of causing a polymerization reaction of the component (a), and specific examples thereof 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, azobis-2,4-
Examples include azo compounds such as dimethylvaleronitrile; peroxide compounds such as benzoyl peroxide and di-tert-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. Particularly preferred photopolymerization initiators (c) for use in the present invention are those capable of forming a complex with a hydrolyzate of a silane compound having a methylene hydrogen adjacent to a nitrogen atom, and such a photopolymerization initiator. When an initiator is used, hydrogen bonded to carbon is extracted by the above-described mechanism and radical polymerization is started, so that the polymer of the component (a) is firmly bonded to the silica surface via a hydrolyzate of a silane compound. be able to. Specific examples of such a photopolymerization initiator include:
Benzophenone derivatives and thioxanthone derivatives can be mentioned.

The amount 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 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 necessary containing an organic solvent. As the organic solvent, one that can be mixed uniformly with the component (a) and the photopolymerization initiator and that can uniformly disperse the component (b) is used. Suitable are those having a boiling point at normal pressure of 50 ° C. or more and 200 ° C. or less and a viscosity at normal 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.

[0049]

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) Wear 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 coating film The sample was cut by eleven vertical and horizontal lines at intervals of 1 mm with a razor blade to form 100 gobangs, and after adhering a commercially available cellophane tape, 90 ° forward. 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, manufactured by 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.

Example 1 N-phenyl-γ-aminopropyltrimethoxy was added to 50 parts by weight of isopropyl alcohol-dispersed colloidal silica (silica content: 30% by weight, trade name: OSCAL-1432, manufactured by Kasei Kagaku Kogyo KK). 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.
Thereafter, 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
A part by weight was 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.

<Examples 2 to 5 and Comparative Examples 1 and 2>
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 6> To 30 parts by weight of the same colloidal silica 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. And stirred at 40 ° C. for 1 hour.
Thereafter, 30 parts by weight of C6DA and 20 parts of a condensate (hereinafter abbreviated as TAS) of trimethylolethane / acrylic acid / succinic acid (molar ratio: 2/4/1) were added, and almost all volatile components were 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. Thereafter, volatile components were 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.

This coating composition was cured in the same manner as in Example 1 to obtain a resin plate whose surface was protected by a cured film. Table 2 shows the evaluation results.

<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 obtain a cured film. Thus, a resin plate whose surface was protected was obtained. Table 2 shows the evaluation results.

EXAMPLE 9 25 parts by weight of N, N-dimethyl-m-aminophenol, 37.4 parts by weight of γ-trimethoxysilylpropyl isocyanate and 0.02 parts by weight of di-n-butyltin dilaurate were mixed. At 60 C for 18 hours to obtain a viscous liquid. According to the infrared absorption spectrum and ¹ H-NMR spectrum of the product, 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 It was confirmed that -γ-trimethoxysilylpropyl carbamate was produced (hereinafter abbreviated as DMPTS).

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Embedded image 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. Tables 1 and 2 show the composition of the coating solution and the evaluation results of the resin plate, respectively.

Example 10 To 100 parts by weight of the same colloidal silica used in Example 1, 11.2 parts by weight of PAPTS and 3 parts by weight of deionized water were added, and the mixture was stirred at 40 ° C. for 1 hour. Thereafter, bis (acryloyloxyethyl) hydroxyethyl isocyanurate (trade name ARONIX M, manufactured by Toagosei Co., Ltd.)
-215) 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 was added thereto.
And 2.4 parts by weight of methylphenylglyoxylate ,
5 parts by weight of UA-1 was added and dissolved as an ultraviolet absorber to obtain 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.
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.

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

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

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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, it is possible to reduce the aesthetic property of a synthetic resin molded article due to scratches which has conventionally been a problem. Various problems can be solved.

Continuation of the front page (72) Inventor Hiroyuki Watanabe 20-1 Miyuki-cho, Otake City, Hiroshima Prefecture Inside Mitsubishi Rayon Co., Ltd. Central Research Laboratory (56) References JP-A-3-56514 (JP, A) JP-A-5-565 86308 (JP, A) Patent 3035468 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 7/12

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) A mixture comprising the above and a compound (a-2) copolymerizable therewith, (B) general formula (I) wherein 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;
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 has been modified with a hydrolyzate of a silane compound represented by the formula: and (c) a photopolymerization initiator. 2. A molded article whose surface is coated with a cured product of the coating composition of claim 1.