JP2015120892A - Clear coat composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a clear coat composition which has low colorability, has a high refractive index without using a filler, shows a glossy feeling even when a filler is used, and can be coated in a thick film.SOLUTION: Provided is a clear coat composition for top coat, comprising an aromatic ring-containing (meth)acrylate, a functional group-containing (meth)acrylate-based polymer obtained by copolymerizing a functional group-monomer represented by formula (I), and a crosslinking group. [Ris H or a methyl group; and Ris a hydroxyl group; a carboxyl group; an epoxy group; a C1-4 alkyl group having a hydroxyl group, carboxyl group, or an epoxy group; a hydroxyalkyloxycarbonyl group where the hydroxyalkyl group has 1 to 4 carbon atoms; or a group represented by the following formula (n is an integer of 3 to 20).]

Description

  The present invention relates to a clearcoat composition. More specifically, the present invention relates to an object to be coated such as a skin of a car body of a car such as a passenger car, a truck, a motorcycle, or a bus, and a skin of a home electric product such as an automobile part, an electronic device, a mobile phone, or an audio device. In particular, the present invention relates to a clear coat composition that can be suitably used for coatings such as outer panels of automobile bodies and automobile parts.

  As a coating resin composition that forms a coating film that has a high refractive index, excellent heat resistance, heat aging resistance and mechanical properties, and also excellent chemical resistance, solvent resistance, and adhesion to a substrate. There has been proposed a coating resin composition comprising a graft-modified cyclic olefin polymer obtained by graft polymerization of an olefin polymer with a hydroxyl group-containing unsaturated compound, and a curing agent (for example, see Patent Document 1). In addition, as a coating material used in a coating film forming method for forming a coating film excellent in a sense of depth, smoothness and sharpness, a colored base coating material (A), a clear coating material (B) and a clear coating material (C) are used. It has been proposed that the refractive index of the cured coating film of the clear coating (B) be 0.02 or more larger than the refractive index of the cured coating film of the clear coating (C) (see, for example, Patent Document 2). ).

  In general, in order to increase the refractive index of a coating film, a filler such as metal oxide particles is added to a paint used as a raw material for the coating film. However, when the filler is added to the paint, not only the transparency of the formed coating film is lowered, but also the filler may be aggregated, so it is difficult to increase the thickness of the coating film. Since it settles in the paint over time, it is difficult to uniformly disperse the filler in the paint.

  Therefore, in recent years, a clear coat composition that has low colorability, has a high refractive index without using a filler, has an excellent gloss feeling even when a filler is used, and can be applied to a thick film. The development of is awaited.

JP-A-5-302057 Japanese Patent Laid-Open No. 10-05679

  The present invention has been made in view of the prior art, has a high refractive index without using a filler, and changes in glossiness, sharpness and hue even when a filler is used. It is an object of the present invention to provide a clear coat composition that provides the above.

The present invention
(1) A clearcoat composition for use in a topcoat, comprising an aromatic ring-containing (meth) acrylate and formula (I):

[Wherein, R ¹ is a hydrogen atom or a methyl group, R ² is a hydroxyl group, a C 1-4 alkyl group having a hydroxyl group, a carboxyl group, a C 1-4 alkyl group having a carboxyl group, an epoxy group or an epoxy. An alkyl group having 1 to 4 carbon atoms having a group, a hydroxyalkyloxycarbonyl group having 1 to 4 carbon atoms of a hydroxyalkyl group, or a formula:

(Wherein n represents an integer of 3 to 20)
A clear coat composition comprising a functional group-containing (meth) acrylate polymer obtained by polymerizing a monomer component containing a functional group-containing monomer represented by formula (2), and (2) The clearcoat composition according to (1), further comprising a filler having an average particle diameter of 3 to 30 nm in an amount of 0 to 25 parts by mass per 100 parts by mass of the functional group-containing (meth) acrylate polymer. About.

  According to the present invention, a clear coat that has low colorability, has a high refractive index without using a filler, has an excellent gloss feeling even when a filler is used, and can be applied to a thick film. A composition is provided.

  As described above, the clear coat composition of the present invention is a clear coat composition used for a top coat, and contains an aromatic ring-containing (meth) acrylate and formula (I):

[Wherein, R ¹ is a hydrogen atom or a methyl group, R ² is a hydroxyl group, a C 1-4 alkyl group having a hydroxyl group, a carboxyl group, a C 1-4 alkyl group having a carboxyl group, an epoxy group or an epoxy. An alkyl group having 1 to 4 carbon atoms having a group, a hydroxyalkyloxycarbonyl group having 1 to 4 carbon atoms of a hydroxyalkyl group, or a formula:

(Wherein n represents an integer of 3 to 20)
It contains a functional group-containing (meth) acrylate polymer obtained by polymerizing a monomer component containing a functional group-containing monomer represented by formula (II) and a crosslinking agent.

  In the present invention, “(meth) acrylate” means acrylate or methacrylate, and acrylate and methacrylate may be used alone or in combination. “(Meth) acrylic acid” means acrylic acid or methacrylic acid, and acrylic acid and methacrylic acid may be used alone or in combination.

  Examples of the aromatic ring-containing (meth) acrylate include aryl (meth) acrylate and aralkyl (meth) acrylate, but the present invention is not limited to such examples. In addition, the aryl group of aryl (meth) acrylate and the aralkyl group of aralkyl (meth) acrylate may have a substituent within the range which does not inhibit the objective of this invention.

  As an aryl group which aryl (meth) acrylate has, carbon number, such as a phenyl group, a tolyl group, a xylyl group, a biphenyl group, a naphthyl group, an anthranyl group, a phenanthralyl group, becomes like this, Preferably it is 6-30, More preferably Examples of the aryl group include 6 to 18, more preferably 6 to 12, and the present invention is not limited to such examples.

  The aralkyl group (also referred to as an aralkyl group) possessed by the aralkyl (meth) acrylate has, for example, preferably 7 to 30, more preferably 7 carbon atoms such as a benzyl group, a phenylethyl group, a methylbenzyl group, and a naphthylmethyl group. -18, more preferably 7-12 aralkyl groups and the like can be mentioned, but the present invention is not limited to such examples.

  Aromatic ring-containing (meth) acrylates have low colorability, have a high refractive index without using fillers, and are excellent in gloss even when using fillers, and can be applied to thick films. From the viewpoint of obtaining a clear coat composition that can be produced, an aromatic ring-containing (meth) acrylate having a refractive index of 1.50 or more is preferred.

  Examples of the aromatic ring-containing (meth) acrylate having a refractive index of 1.50 or more include benzyl (meth) acrylate, naphthyl (meth) acrylate, anthranyl (meth) acrylate, phenanthryl (meth) acrylate, and 2- (naphthoxy). Carbonylamino) ethyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, o-phenylphenoxyethyl (meth) acrylate, 2- (meth) ) Acryloyloxyethyl-2-hydroxyethylphthalic acid, 2,2-bis [4- (meth) acryloyloxyethoxyphenyl] propane, 2,2-bis [4- (meth) acryloyloxydiethoxypheny ] Propane, 2,2-bis [4- (meth) acryloyloxypolyethoxyphenyl] propane, 2,2-bis [4- (meth) acryloyloxydiethoxyphenyl] propane, 1- (meth) acryloyloxy-2 , 4,6-tribromobenzene, 1- (meth) acryloylethoxy-2,4,6-tribromobenzene, paracumylphenol ethylene oxide modified (meth) acrylate, nonylphenol ethylene oxide modified (meth) acrylate, N, N-dimethyl Benzyl chloride salt of aminoethyl (meth) acrylate, benzyl chloride salt of N, N-diethylaminoethyl (meth) acrylate, benzyl chloride salt of N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminopropyl (meth) ) Benzyl chloride salt of acrylate, p-toluenesulfonic acid alkyl (carbon number of alkyl group: 1 to 18) salt of N, N-dimethylaminoethyl (meth) acrylate, p of N, N-diethylaminoethyl (meth) acrylate -Toluenesulfonic acid alkyl (carbon number of alkyl group: 1-18) salt, p-toluenesulfonic acid alkyl (carbon number of alkyl group: 1-18) salt of N, N-dimethylaminopropyl (meth) acrylate, N , N-diethylaminopropyl (meth) acrylate p-toluenesulfonic acid alkyl (carbon number of alkyl group: 1 to 18) salt, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, Hydroxyl group content such as 4-hydroxybutyl (meth) acrylate (meta ) Phthalic anhydride adducts of acrylates and the like, but the present invention is not limited to such examples. These aromatic ring-containing (meth) acrylates may be used alone or in combination of two or more.

  Among the aromatic ring-containing (meth) acrylates, benzyl (meth) acrylate, naphthalene (meth) acrylate, anthranyl (meth) acrylate, phenanthryl (meth) acrylate and naphthalene-containing urethane-modified methacrylate are preferable, and benzyl (meth) acrylate and anthranyl (Meth) acrylate and 2- (naphthoxycarbonylamino) ethyl (meth) acrylate are more preferred. These aromatic ring-containing (meth) acrylates may be used alone or in combination of two or more.

  The monomer component used in the present invention includes the aromatic ring-containing (meth) acrylate and the formula (I):

[Wherein, R ¹ is a hydrogen atom or a methyl group, R ² is a hydroxyl group, a C 1-4 alkyl group having a hydroxyl group, a carboxyl group, a C 1-4 alkyl group having a carboxyl group, an epoxy group or an epoxy. An alkyl group having 1 to 4 carbon atoms having a group, a hydroxyalkyloxycarbonyl group having 1 to 4 carbon atoms of a hydroxyalkyl group, or a formula:

(Wherein n represents an integer of 3 to 20)
A functional group-containing monomer represented by

  The functional group-containing monomer is used to introduce a functional group into the resulting polymer. Examples of the functional group possessed by the functional group-containing monomer include a hydroxyl group, a carboxyl group, and an epoxy group. These functional groups may be used alone in one molecule, or a plurality of the same or different functional groups may exist in one molecule.

In the functional group-containing monomer represented by the formula (I), R ¹ is a hydrogen atom or a methyl group. R ² is a hydroxyl group, an alkyl group having 1 to 4 carbon atoms having a hydroxyl group, a carboxyl group, an alkyl group having 1 to 4 carbon atoms having a carboxyl group, an epoxy group or an alkyl group having 1 to 4 carbon atoms having an epoxy group. A hydroxyalkyloxycarbonyl group wherein the hydroxyalkyl group has 1 to 4 carbon atoms or a group:

(Wherein n represents an integer of 3 to 20). Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group.

  Examples of the functional group-containing monomer represented by the formula (I) include vinyl alcohol, (meth) allyl alcohol, hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl. (Meth) acrylate, (meth) acrylic acid, allyl carboxylic acid, glycidyl (meth) acrylate, polyethylene glycol mono (meth) acrylate having an added mole number of ethylene oxide group of 3-20 [for example, manufactured by Nippon Emulsifier Co., Ltd., Trade names: MA-50A, MA-80A, MA-100A, MA-150MF, etc.], etc., but the present invention is not limited to such examples. These functional group-containing monomers may be used alone or in combination of two or more.

  In the present invention, “(meth) acrylic acid” means acrylic acid or methacrylic acid, and acrylic acid and methacrylic acid may be used alone or in combination.

  Among the functional group-containing monomers represented by the formula (I), the coloring property is low, it has a high refractive index without using a filler, and is excellent in gloss even when a filler is used. From the viewpoint of obtaining a clear coat composition that can be applied to a thick film, hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate, (meth) acrylic acid, and glycidyl (meth) acrylate are preferred. These functional group-containing monomers may be used alone or in combination of two or more.

  The content of the aromatic ring-containing (meth) acrylate and the content of the functional group-containing monomer in the monomer component vary depending on the functional group of the cross-linking agent described later and the amount of use thereof. However, by sufficiently reacting the resulting functional group-containing (meth) acrylate polymer and the crosslinking agent, the coloring property is low, and the filler has a high refractive index without using a filler. From the viewpoint of obtaining a clear coat composition that is excellent in gloss even when used, and can be applied to a thick film, the content of the aromatic ring-containing (meth) acrylate is usually preferably from 5 to 90% by mass. More preferably, it is 10-85 mass%, More preferably, it is 15-80 mass%, The content rate of a functional group containing monomer becomes like this. Preferably it is 10-95 mass%, More preferably, it is 15-90 mass% More preferably 20 to 85 wt%.

  In the present invention, the monomer component includes other monomers (hereinafter simply referred to as aromatic ring-containing (meth) acrylate and functional group-containing monomers) within a range that does not impair the object of the present invention. "Other monomer") may be contained in an appropriate amount.

  Examples of the other monomer include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, and tert-butyl (meth) acrylate. , N-amyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, decyl (meth) acrylate Alkyl (meth) acrylates such as dodecyl (meth) acrylate; N-substituted (meth) acrylamides such as N-methylol (meth) acrylamide and N-butoxymethyl (meth) acrylamide; (meth) acrylonitrile Aliphatic (meth) acrylic monomer having a carbon-carbon unsaturated double bond; other than the aromatic ring-containing (meth) acrylate such as styrene, α-methylstyrene, tert-butylstyrene, chlorostyrene, vinyltoluene However, the present invention is not limited to such examples. These other monomers may be used alone or in combination of two or more.

  The content of other monomers in the monomer component is low in colorability, has a high refractive index without the use of fillers, and is excellent in glossiness even when fillers are used. From the viewpoint of obtaining a clear coat composition that can be applied to the film, it is preferably 85% by mass or less, more preferably 75% by mass or less, and still more preferably 65% by mass or less.

  Examples of the method for polymerizing the monomer component include a bulk polymerization method, a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, and the like, but the present invention is not limited to such examples. Among these polymerization methods, the solution polymerization method is preferable.

  When the monomer component is polymerized by a solution polymerization method, for example, the polymerization initiator is dissolved in an organic solvent, and the monomer component is added to the solution while stirring the obtained solution. In addition to polymerizing the components, the monomer components can be polymerized by dissolving the monomer components in an organic solvent and adding the polymerization initiator to the solution while stirring the resulting solution.

  Examples of the organic solvent include ketone compounds such as acetylacetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, and isophorone, ether compounds such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and dioxane, butyl acetate, ethylene glycol monomethyl ether acetate, Examples include acetates such as ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate; hydrocarbon compounds such as toluene and xylene, but the present invention is limited to such examples only. is not. These solvents may be used alone or in combination of two or more. Usually, the amount of the organic solvent is preferably adjusted so that the concentration of the monomer component is 15 to 80% by mass.

  When polymerizing the monomer component, it is preferable to use a polymerization initiator. Examples of the polymerization initiator include azobisisobutyronitrile, azoisobutyronitrile, methyl azoisobutyrate, azobisdimethylvaleronitrile, benzoyl peroxide, potassium persulfate, ammonium persulfate, benzophenone derivatives, phosphine oxide derivatives, benzoketones Derivatives, phenylthioether derivatives, azide derivatives, diazo derivatives, disulfide derivatives and the like can be mentioned, but the present invention is not limited to such examples. These polymerization initiators may be used alone or in combination of two or more. Although the quantity of a polymerization initiator is not specifically limited, Usually, it is preferable that it is about 0.05-20 mass parts per 100 mass parts of monomer components.

  A chain transfer agent may be used when the monomer component is polymerized. The chain transfer agent can be used usually by mixing with a monomer component. Examples of the chain transfer agent include mercaptan group-containing compounds such as lauryl mercaptan, dodecyl mercaptan, and thioglycerol, and inorganic salts such as sodium hypophosphite and sodium hydrogen sulfite. It is not limited. These chain transfer agents may be used alone or in combination of two or more. Although the quantity of a chain transfer agent is not specifically limited, Usually, it is preferable that it is about 0.01-10 mass parts per 100 mass parts of monomer components.

  There is no particular limitation on the polymerization reaction temperature and atmosphere when the monomer components are polymerized. Usually, the polymerization reaction temperature is about 60 to 200 ° C. The atmosphere during the polymerization reaction is preferably an inert gas atmosphere such as nitrogen gas, for example. In addition, the polymerization reaction time of the monomer component varies depending on the polymerization reaction temperature and the like and cannot be determined unconditionally, but is usually about 3 to 20 hours.

  By polymerizing the monomer component as described above, a functional group-containing (meth) acrylate polymer is obtained.

  The weight average molecular weight of the functional group-containing (meth) acrylate polymer is preferably 1000 to 500,000, more preferably 4500 to 100,000, considering the film-forming property of the clear coat composition and the workability during coating. . In addition, the weight average molecular weight of a functional group containing (meth) acrylate type polymer is a value when measured based on the method as described in a following example.

  Next, a clear coat composition is obtained by mixing the functional group-containing (meth) acrylate polymer obtained above and a crosslinking agent. In addition, when the functional group-containing (meth) acrylate polymer is prepared by a solution polymerization method, a reaction solution containing the functional group-containing (meth) acrylate polymer obtained by the solution polymerization method is used. The reaction solution and the crosslinking agent can be mixed.

  A typical example of the crosslinking agent is a thermosetting crosslinking agent. Examples of the thermosetting crosslinking agent include melamine resin, polyisocyanate, epoxy resin, polyvalent carboxylic acid, and the like, but the present invention is not limited only to such illustration. These crosslinking agents may be used alone or in combination of two or more. Among these crosslinking agents, melamine resin, polyisocyanate and epoxy resin are preferable, and polyisocyanate is more preferable.

  Examples of the melamine resin include a methylated melamine resin and a butylated melamine resin, but the present invention is not limited to such examples. These melamine resins may be used alone or in combination of two or more.

  Examples of polyisocyanates include bifunctional isocyanates such as hexamethylene diisocyanate, N, N ′, N ″ -tri (6-isocyanatohexyl) isocyanurate, toluene diisocyanate, and methylene bisphenyl diisocyanate; triphenylmethane triisocyanate, bicyclo Although trifunctional isocyanates, such as heptane triisocyanate and dibenzylbenzene triisocyanate, are mentioned, this invention is not limited only to this illustration. These polyisocyanates may be used alone or in combination of two or more.

  Examples of the epoxy resin include bisphenol diglycidyl ether, bifunctional reaction type epoxy resin [for example, manufactured by ADEKA, trade name: Adekaglycylol ED-503, etc.], diglycidyl phthalate, triglycidyl isocyanurate, Examples include phenol novolac epoxy resins and cresol novolac epoxy resins, but the present invention is not limited to such examples. These epoxy resins may be used alone or in combination of two or more. May be.

  Examples of the polyvalent carboxylic acid include divalent carboxylic acids such as phthalic acid, adipic acid and tetrahydrophthalic anhydride and anhydrides thereof, trimellitic acid and anhydride thereof, pyromellitic acid and anhydride thereof, and the like. The present invention is not limited to such examples. These polyvalent carboxylic acids may be used alone or in combination of two or more.

  Regarding the ratio between the functional group-containing (meth) acrylate polymer and the crosslinking agent, from the viewpoint of reducing the residual amount of the functional group-containing (meth) acrylate polymer or crosslinking agent, the functional group-containing (meth) acrylate-based polymer is used. The molar ratio between the total amount (mol) of the functional group possessed by the coalescence and the total amount (mol) of the functional group of the crosslinking agent that reacts with the functional group possessed by the functional group-containing (meth) acrylate polymer [functional group content (meth) The total amount of functional groups (mole) of the acrylate polymer / the total amount of functional groups (mole) of the cross-linking agent is 1/1 stoichiometrically, preferably 1/3 to 3/1. More preferably, it is 1 / 2-2 / 1.

  The amount of the crosslinking agent per 100 parts by mass of the functional group-containing (meth) acrylate polymer (solid content) is the functional group the functional group-containing (meth) acrylate polymer contained in the clear coat composition has. It is preferable to select appropriately according to the kind of the functional group and the number of functional groups. The content of the crosslinking agent in the clear coat composition is low in colorability, has a high refractive index without using a filler, and is excellent in gloss even when using a filler, and is applied to a thick film. From the viewpoint of obtaining a clear coat composition that can be used, it is preferably 1 to 60 parts by mass, more preferably 2 to 40 parts by mass, and further preferably 3 to 30 parts by mass.

  The clear coat composition can contain a filler as long as the object of the present invention is not impaired. When a filler is contained in the clear coat composition, the refractive index of the clear coat composition can be increased.

  Examples of the filler include metal fillers made of metals such as silver, gold, platinum, palladium, silver-platinum alloys, and palladium-platinum alloys, and metal oxide fillers such as silica, alumina, zirconia, and titania. However, the present invention is not limited to such examples. These fillers may be used alone or in combination of two or more.

  The average particle size of the filler is preferably 3 nm or more, more preferably 5 nm or more from the viewpoint of suppressing secondary aggregation of the particles, and preferably 30 nm or less from the viewpoint of improving the uniformity of the coating film to be formed. More preferably, it is 25 nm or less, and further preferably 20 nm or less. In addition, the average particle diameter of a filler is a value when it measures using the dynamic light-scattering type particle size distribution measuring apparatus [The Nikkiso Co., Ltd. make, brand name: Nanotrac Wave-EX150].

  The amount of the filler (solid content) per 100 parts by mass of the functional group-containing (meth) acrylate polymer (solid content) is 0 part by mass or more, preferably from the viewpoint of increasing the refractive index of the clear coat composition. Is 1 part by mass or more, more preferably 3 parts by mass or more, further preferably 5 parts by mass or more, and from the viewpoint of increasing the transparency of the formed coating film and increasing the thickness of the coating film, preferably 25 parts by mass. Hereinafter, it is more preferably 20 parts by mass or less, further preferably 15 parts by mass or less, and still more preferably 10 parts by mass or less.

  In addition, from the viewpoint of improving the curability of the clear coat composition, the clear coat composition may contain an appropriate amount of a curing catalyst.

  Examples of the curing catalyst include monomethyl stannic acid, monobutyl tin oxide, monobutyl tin hydroxide, monobutyl tin trioctoate, monobutyl stannic acid, monobutyl tin tris (2-ethylhexoate), butyl tin trichloride, butyl tin trimethylate. , Monophenyltin tribromide, dimethyltin oxide, dibutyltin oxide, dibutyltin dibromide, dibutyltin dichloride, diphenyltin dichloride, dibutyltin diacetate, dioctyltin diacetate, dibutyltin maleate, dibutyltin dithiol, dibutyltin bis (2- Ethylhexoate), dibutyltin sulfide, diphenyltin sulfide, dibutyltin dilaurate, dioctyltin oxide, dioctyltin dilaurate, dioctyltin dimethoxide, diocti Tin dibutoxide, triphenyltin acetate, diphenyltin dichloride, tributyltin chloride, tetra-n-butyl-1,3-diacetoxydistanoxane, tetra-n-butyl-1,3-dioctyloxydistanoxane, tetra- Tin-based curing catalyst such as n-butyl-1,3-dilauryloxydistanoxane; dimethylbenzylamine, ethanolamine, N-methylethanolamine, triethanolamine, N, N-dimethylethanolamine, n-butylamine, Diethylamine, triethylamine, 1,4-diazabicyclo [2.2.2] octane, tetramethylenediamine, cyclohexylamine, imidazole, 1-methylimidazole, 2,4-dimethylimidazole, 1,4-diethylimidazole, tetramethyladiene Quaternary ammonium salts such as monium, tetrabutylammonium, trimethyl (2-hydroxypropyl) ammonium, cyclohexyltrimethylammonium, tetrakis (hydroxymethyl) ammonium, dilauryldimethylammonium, methylammonium, o-trifluoromethylphenyltrimethylammonium; An amine-based curing catalyst such as a quaternary ammonium salt having a chloride, bromide, carbonate or hydroxide as an anion can be mentioned, but the present invention is not limited to such examples. These curing catalysts may be used alone or in combination of two or more. Among these curing catalysts, triethylenediamine, 1,4-diazabicyclo [2.2.2] octane and triethylamine are preferable, and triethylamine is more preferable.

  The amount of the curing catalyst is not particularly limited, but is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and still more preferably 0.1 parts by mass per 100 parts by mass of the functional group-containing (meth) acrylate polymer. It is 3 parts by mass or more, and even if it is used in an excessive amount, it cannot be expected to have much effect, so it is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less. It is.

  In the present invention, in order to improve the adhesiveness of the clear coat composition, for example, methyltrimethoxysilane, vinyltrimethoxysilane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ-glycol is used as necessary. Even if a silane coupling agent such as sidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and γ-glycidoxypropylmethyldiethoxysilane is contained in an appropriate amount in the clearcoat composition. Good.

  The clear coat composition of the present invention can be easily prepared by mixing the respective components. These components can be prepared to have a uniform composition, for example, by dissolving them in an appropriate amount in an appropriate solvent. In this case, the amount of the solvent is preferably adjusted so that the solid content concentration of the clear coat resin composition in the solution of the clear coat composition is about 15 to 80% by mass.

  Examples of the solvent include ketone compounds such as acetylacetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, and isophorone, ether compounds such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and dioxane, butyl acetate, ethylene glycol monomethyl ether acetate, and ethylene. Examples thereof include acetic acid esters such as glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate, but the present invention is not limited to such examples. These solvents may be used alone or in combination of two or more. Of these solvents, butyl acetate, ethylene glycol monomethyl ether acetate, diethylene glycol dimethyl ether acetate and cyclopentanone are preferred because of their excellent solubility in the clear coat composition of the present invention. From the viewpoint of improving the properties, cyclopentanone is more preferable.

  The order of mixing the components and the concentration of the clear coat composition in the solution of the clear coat composition are not particularly limited, and are preferably appropriately selected according to the use of the clear coat composition of the present invention, the coating method, and the like. .

  The concentration of the clear coat composition in the solution of the clear coat composition is usually preferably about 15 to 80% by mass from the viewpoint of enhancing the coatability and preventing the coating film from becoming too thick.

  The clear coat composition of the present invention includes, for example, colorants such as pigments and dyes, aqueous resins, rheology control agents, dispersants, antifoaming agents, and antioxidants within a range that does not impair the object of the present invention. In addition, an ultraviolet absorber or the like may be contained.

  Examples of the method for applying the clear coat composition of the present invention include a spray method, a spin coat method, and a roll coater method, but the present invention is not limited to such examples.

  Examples of the material used for the object to which the clear coat composition of the present invention can be applied include, for example, iron, aluminum, brass, copper, tinplate, stainless steel, galvanized steel, zinc-aluminum alloy, and zinc-nickel. Metals such as alloys, zinc-based alloys such as zinc-iron alloys; resins such as polyethylene, polypropylene, acrylonitrile-butadiene-styrene (ABS) resin, polyamide, acrylic resin, vinylidene chloride resin, polycarbonate, polyurethane, epoxy resin; glass, Examples include inorganic materials such as mortar, cement, and concrete; wood; fibers such as paper, woven fabric, and non-woven fabric, but the present invention is not limited to such examples. Of these materials, metals and resins are preferred in the present invention.

  The clear coat composition of the present invention can be applied to an object to be coated, and the formed coating film can be dried by heating. The formed coating film can be dried by heating, for example, by heating the coating film at a temperature of 60 to 170 ° C. for 10 to 40 minutes.

  Moreover, it is preferable to adjust the thickness after drying of the formed coating film to about 15-60 micrometers. When the clear coat composition of the present invention is used, there is an advantage that a coating film having a film thickness can be formed in this way.

  As described above, the clear coat composition of the present invention has low colorability, has a high refractive index without using a filler, and has an excellent gloss feeling even when a filler is used. Because it can be applied to the film, for example, the outer panel of automobile bodies such as passenger cars, trucks, motorcycles, buses, etc., the outer panel of household electrical products such as automobile parts, electronic devices, mobile phones, audio equipment, etc. The present invention can be suitably used for objects such as outer panels of automobile bodies and automobile parts.

  Next, the present invention will be described in more detail based on examples. However, the present invention is not limited to such examples.

Preparation Example 1
In a reaction vessel equipped with a stirrer, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, 100 parts by mass of naphthol, 90 parts by mass of methyl ethyl ketone and 0.1 part by mass of dibutyltin dilaurate were charged, and the temperature was raised to 60 ° C. It was. Thereafter, 105 parts by mass of 2-methacryloyloxyethyl isocyanate [manufactured by Showa Denko KK, trade name: Karenz MOI] was dropped into the reaction vessel over 2 hours and aged for 3 hours.

  Next, the reaction solution obtained above was added to 2000 parts by mass of n-hexane, the precipitate was collected, and dried with an evaporator until there was no mass change of the precipitate, whereby 2- (naphthoxycarbonylamino ) Ethyl methacrylate (hereinafter referred to as NFM) was obtained.

Example 1
Put 230 parts by mass of butyl acetate in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and 80 ° C. with stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to.

  Next, 10 parts by mass of azobisisobutyronitrile is added to the reaction vessel while maintaining a temperature of 80 ° C., and the azobisisobutyronitrile is dissolved in the contents in the reaction vessel. 45 parts by mass, 30 parts by mass of n-butyl methacrylate and 25 parts by mass of 2-hydroxyethyl acrylate were dropped into the reaction vessel over 3 hours. After completion of the dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having a hydroxyl group as a functional group. The obtained functional group-containing (meth) acrylate polymer had a hydroxyl value of 121 mgKOH / g and a weight average molecular weight of 6000.

  In addition, the hydroxyl value, acid value, epoxy equivalent, and weight average molecular weight of the functional group-containing (meth) acrylate polymer were measured based on the following methods.

[Hydroxyl value]
It measured based on JIS-K1557.

[Acid value]
It measured based on JIS-K5601.

[Epoxy equivalent]
It measured based on JIS-K7147.

(Weight average molecular weight)
Tetrahydrofuran was used as a developing solvent, and measurement was performed by gel permeation chromatography [manufactured by Tosoh Corporation, product number: HLC-8320GPC].

  Next, 100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above and 0.5 parts by mass of dibutyltin dilaurate are mixed, and the functional group-containing (meth) acrylate polymer has a functional group. A clear coat composition was obtained by mixing hexamethylene diisocyanate so that the molar ratio of the total amount (mol) to the total amount (mol) of the functional group of hexamethylene diisocyanate was 1: 1.

  As the physical properties of the clear coat composition obtained above, refractive index, glossiness and colorability were evaluated based on the following methods. The results are shown in Table 1.

[Method for measuring physical properties of clear coat composition]
(1) Refractive index The clear coat composition was applied to a polyester (polyethylene terephthalate) film so that the thickness after drying was 30 μm, and the film on which the coating film was formed was placed in a constant temperature bath at 100 ° C. for 20 minutes. A test piece was prepared by drying. The refractive index of the coating film of the obtained test piece was measured with a prism coupler (manufactured by Metricon, trade name: Model 2010).

(2) Glossiness and colorability (preparation of coated material)
An intermediate coating (made by Nippon Paint Co., Ltd., trade name: ORGER P-5U) was applied on the cationic electrodeposited steel sheet so that the thickness of the coating film after drying was 30 μm, and in an atmosphere of 140 ° C. After heating for 20 minutes, the base paint [Nippon Paint Co., Ltd., trade name: Aqualex AR2100] colored in black on the formed paint film is dried so that the thickness of the paint film becomes 10 μm. The object A was prepared by applying and heating in an atmosphere at 80 ° C. for 10 minutes.

  The surface of the polypropylene resin plate was washed and degreased, and then a primer [manufactured by Nippon Bee Chemical Co., Ltd., product number: RB116] was applied so that the thickness of the coated film after drying was 10 μm. After heating for 10 minutes in the atmosphere, the thickness of the coating film after drying the base paint [Nihon Bee Chemical Co., Ltd., product number: R301] colored in black on the formed coating film becomes 10 μm. The object to be coated B was produced by applying the film in the manner described above and heating in an atmosphere of 80 ° C. for 10 minutes.

(Preparation of test piece)
Apply the clear coat composition on the surface of the object A or B to be coated shown in Table 1 so that the thickness of the coating film after drying is 30 μm, and heat in an atmosphere of 100 ° C. for 20 minutes. Thus, a test piece was prepared.

  The glass transition temperature of the functional group-containing (meth) acrylate polymer constituting the coating film using this test piece is measured with a thermomechanical analyzer (manufactured by Seiko Instruments Inc., product number: TMA / SS-6000). As a result, the glass transition temperature of the functional group-containing (meth) acrylate polymer was 40 ° C.

A. Glossiness The coating film of the test piece obtained above was visually observed and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: The coating film has a very strong gloss.
○: The coating film has a strong gloss.
Δ: Some glossiness is present in the coating film.
X: A glossiness does not exist in a coating film.

B. Colorability The b ^* in the coating film of the test piece was measured using an ultraviolet-visible spectrophotometer [manufactured by JASCO Corporation, product number: V-660]. In addition, a coating film becomes colorless and transparent, so that the value of b ^* is small.

Example 2
Put 230 parts by mass of butyl acetate in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and 80 ° C. with stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to.

  Next, 10 parts by mass of azobisisobutyronitrile is added to the reaction vessel while maintaining a temperature of 80 ° C., and the azobisisobutyronitrile is dissolved in the contents in the reaction vessel. 75 parts by mass and 25 parts by mass of 2-hydroxyethyl acrylate were dropped into the reaction vessel over 3 hours. After completion of the dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having a hydroxyl group as a functional group. The functional group-containing (meth) acrylate polymer thus obtained had a hydroxyl value of 121 mgKOH / g and a weight average molecular weight of 6000. The glass transition temperature of the coating film of the test piece prepared in the same manner as described above was 55 ° C. It was.

  100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above and 0.5 part by mass of dibutyltin dilaurate are mixed, and the total amount of functional groups (mol) of the functional group-containing (meth) acrylate polymer. ) And hexamethylene diisocyanate were mixed so that the molar ratio of the functional group of hexamethylene diisocyanate to the total amount (mole) was 1: 1 to obtain a clear coat composition.

  As the physical properties of the clear coat composition obtained above, the refractive index, glossiness and colorability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 3
Put 230 parts by mass of butyl acetate in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and 80 ° C. with stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to.

  Next, 10 parts by mass of azobisisobutyronitrile was added to the reaction vessel while maintaining the temperature at 80 ° C., and the azobisisobutyronitrile was dissolved in the contents in the reaction vessel. 15 parts by mass of anthrylmethyl methacrylate, 60 parts by mass of styrene and 25 parts by mass of 2-hydroxyethyl acrylate were dropped into the reaction vessel over 3 hours. After completion of the dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having a hydroxyl group as a functional group. The obtained functional group-containing (meth) acrylate polymer had a hydroxyl value of 121 mgKOH / g and a weight average molecular weight of 4000.

  100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above and 0.5 part by mass of dibutyltin dilaurate are mixed, and the total amount of functional groups (mol) of the functional group-containing (meth) acrylate polymer. ) And hexamethylene diisocyanate were mixed so that the molar ratio of the functional group of hexamethylene diisocyanate to the total amount (mole) was 1: 1 to obtain a clear coat composition.

  As the physical properties of the clear coat composition obtained above, the refractive index, glossiness and colorability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 4
Put 230 parts by mass of butyl acetate in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and 80 ° C. with stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to.

  Next, 10 parts by mass of azobisisobutyronitrile was added to the reaction vessel while maintaining the temperature at 80 ° C., and the azobisisobutyronitrile was dissolved in the contents in the reaction vessel. 30 parts by mass of anthrylmethyl methacrylate, 45 parts by mass of styrene and 25 parts by mass of 2-hydroxyethyl acrylate were dropped into the reaction vessel over 3 hours. After completion of the dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having a hydroxyl group as a functional group. The obtained functional group-containing (meth) acrylate polymer has a hydroxyl value of 121 mgKOH / g and a weight average molecular weight of 4500. The glass transition temperature of the coating film of the test piece prepared in the same manner as described above has high hardness. Therefore, it could not be measured.

  100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above and 0.5 part by mass of dibutyltin dilaurate are mixed, and the total amount of functional groups (mol) of the functional group-containing (meth) acrylate polymer. ) And hexamethylene diisocyanate were mixed so that the molar ratio of the functional group of hexamethylene diisocyanate to the total amount (mole) was 1: 1 to obtain a clear coat composition.

  As the physical properties of the clear coat composition obtained above, the refractive index, glossiness and colorability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 5
Put 230 parts by mass of butyl acetate in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and 80 ° C. with stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to.

  Next, 10 parts by mass of azobisisobutyronitrile was added to the reaction vessel while maintaining the temperature at 80 ° C., and the azobisisobutyronitrile was dissolved in the contents in the reaction vessel. 55 parts by mass of anthrylmethyl methacrylate, 20 parts by mass of benzyl methacrylate and 25 parts by mass of 2-hydroxyethyl acrylate were dropped into the reaction vessel over 3 hours. After completion of the dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having a hydroxyl group as a functional group. The obtained functional group-containing (meth) acrylate polymer has a hydroxyl value of 121 mgKOH / g and a weight average molecular weight of 5000, and the glass transition temperature hardness of the coating film of the test piece prepared in the same manner as described above is determined by the hardness. It was not possible to measure because of its high value.

  100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above and 0.5 part by mass of dibutyltin dilaurate are mixed, and the total amount of functional groups (mol) of the functional group-containing (meth) acrylate polymer. ) And hexamethylene diisocyanate were mixed so that the molar ratio of the functional group of hexamethylene diisocyanate to the total amount (mole) was 1: 1 to obtain a clear coat composition.

  As the physical properties of the clear coat composition obtained above, the refractive index, glossiness and colorability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 6
Put 230 parts by mass of butyl acetate in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and 80 ° C. with stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to.

  Next, 10 parts by mass of azobisisobutyronitrile is added to the reaction vessel while maintaining a temperature of 80 ° C., and the azobisisobutyronitrile is dissolved in the contents in the reaction vessel. 25 parts by mass of the obtained NFM, 50 parts by mass of styrene, and 25 parts by mass of 2-hydroxyethyl acrylate were dropped into the reaction vessel over 3 hours. After completion of the dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having a hydroxyl group as a functional group. The functional group-containing (meth) acrylate polymer thus obtained had a hydroxyl value of 121 mgKOH / g and a weight average molecular weight of 6500, and the glass transition temperature of the coating film of the test piece prepared in the same manner as described above was 75 ° C. It was.

  100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above and 0.5 part by mass of dibutyltin dilaurate are mixed, and the total amount of functional groups (mol) of the functional group-containing (meth) acrylate polymer. ) And hexamethylene diisocyanate were mixed so that the molar ratio of the functional group of hexamethylene diisocyanate to the total amount (mole) was 1: 1 to obtain a clear coat composition.

  As the physical properties of the clear coat composition obtained above, the refractive index, glossiness and colorability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 7
Put 230 parts by mass of butyl acetate in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and 80 ° C. with stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to.

  Next, 10 parts by mass of azobisisobutyronitrile is added to the reaction vessel while maintaining a temperature of 80 ° C., and the azobisisobutyronitrile is dissolved in the contents in the reaction vessel. 75 parts by mass of the obtained NFM and 25 parts by mass of 2-hydroxyethyl acrylate were dropped into the reaction vessel over 3 hours. After completion of the dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having a hydroxyl group as a functional group. The functional group-containing (meth) acrylate polymer thus obtained had a hydroxyl value of 121 mgKOH / g and a weight average molecular weight of 6200, and the glass transition temperature of the coating film of the test piece prepared in the same manner as described above was 90 ° C. It was.

  100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above and 0.5 part by mass of dibutyltin dilaurate are mixed, and the total amount of functional groups (mol) of the functional group-containing (meth) acrylate polymer. ) And hexamethylene diisocyanate were mixed so that the molar ratio of the functional group of hexamethylene diisocyanate to the total amount (mole) was 1: 1 to obtain a clear coat composition.

  As the physical properties of the clear coat composition obtained above, the refractive index, glossiness and colorability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 8
Put 230 parts by mass of butyl acetate in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and 80 ° C. with stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to.

  Next, 10 parts by mass of azobisisobutyronitrile is added to the reaction vessel while maintaining a temperature of 80 ° C., and the azobisisobutyronitrile is dissolved in the contents in the reaction vessel. 75 parts by mass of the obtained NFM and 25 parts by mass of 4-hydroxyptyl acrylate were dropped into the reaction vessel over 3 hours. After completion of the dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having a hydroxyl group as a functional group. The functional group-containing (meth) acrylate polymer thus obtained had a hydroxyl value of 121 mgKOH / g and a weight average molecular weight of 6000. The glass transition temperature of the coating film of the test piece prepared in the same manner as described above was 80 ° C. It was.

  100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above and 0.5 part by mass of dibutyltin dilaurate are mixed, and the total amount of functional groups (mol) of the functional group-containing (meth) acrylate polymer. ) And hexamethylene diisocyanate were mixed so that the molar ratio of the functional group of hexamethylene diisocyanate to the total amount (mole) was 1: 1 to obtain a clear coat composition.

  As the physical properties of the clear coat composition obtained above, the refractive index, glossiness and colorability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 9
Put 230 parts by mass of butyl acetate in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and 80 ° C. with stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to.

  Next, 10 parts by mass of azobisisobutyronitrile was added to the reaction vessel while maintaining the temperature at 80 ° C., and the azobisisobutyronitrile was dissolved in the contents in the reaction vessel. 15 parts by mass of anthrylmethyl methacrylate, 60 parts by mass of benzyl methacrylate, 10 parts by mass of n-butyl methacrylate and 15 parts by mass of 2-hydroxyethyl acrylate were dropped into the reaction vessel over 3 hours. After completion of the dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having a hydroxyl group as a functional group. The obtained functional group-containing (meth) acrylate polymer has a hydroxyl value of 72 mgKOH / g and a weight average molecular weight of 5500, and the glass transition temperature of the coating film of the test piece prepared in the same manner is high in hardness. Therefore, it could not be measured.

  100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above and 0.5 part by mass of dibutyltin dilaurate are mixed, and the total amount of functional groups (mol) of the functional group-containing (meth) acrylate polymer. ) And hexamethylene diisocyanate were mixed so that the molar ratio of the functional group of hexamethylene diisocyanate to the total amount (mole) was 1: 1 to obtain a clear coat composition.

  As the physical properties of the clear coat composition obtained above, the refractive index, glossiness and colorability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 10
Put 230 parts by mass of butyl acetate in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and 80 ° C. with stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to.

  Next, 10 parts by mass of azobisisobutyronitrile was added to the reaction vessel while maintaining the temperature at 80 ° C., and the azobisisobutyronitrile was dissolved in the contents in the reaction vessel. 30 parts by mass of anthrylmethyl methacrylate, 20 parts by mass of benzyl methacrylate, 20 parts by mass of n-butyl methacrylate and 30 parts by mass of 2-hydroxyethyl acrylate were dropped into the reaction vessel over 3 hours. After completion of the dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having a hydroxyl group as a functional group. The obtained functional group-containing (meth) acrylate polymer has a hydroxyl value of 145 mg KOH / g and a weight average molecular weight of 5500. The glass transition temperature hardness of the coating film of the test piece prepared in the same manner as described above is determined by the hardness. It was not possible to measure because of its high value.

  100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above and 0.5 part by mass of dibutyltin dilaurate are mixed, and the total amount of functional groups (mol) of the functional group-containing (meth) acrylate polymer. ) And hexamethylene diisocyanate were mixed so that the molar ratio of the functional group of hexamethylene diisocyanate to the total amount (mole) was 1: 1 to obtain a clear coat composition.

  As the physical properties of the clear coat composition obtained above, the refractive index, glossiness and colorability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 11
Put 230 parts by mass of butyl acetate in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and 80 ° C. with stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to.

  Next, 10 parts by mass of azobisisobutyronitrile was added to the reaction vessel while maintaining the temperature at 80 ° C., and the azobisisobutyronitrile was dissolved in the contents in the reaction vessel. 15 parts by mass of anthrylmethyl methacrylate, 60 parts by mass of styrene and 25 parts by mass of glycidyl methacrylate were dropped into the reaction vessel over 3 hours. After completion of dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having an epoxy group as a functional group. The obtained functional group-containing (meth) acrylate polymer had an epoxy equivalent of 570 g / equivalent and a weight average molecular weight of 4,900.

  100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above and 1.0 part by mass of dimethylbenzylamine were mixed, and the total amount (moles of functional groups of the functional group-containing (meth) acrylate polymer) ) And the total amount (mole) of adipic acid functional groups were mixed so that the molar ratio was 1: 1 to obtain a clear coat composition.

  As the physical properties of the clear coat composition obtained above, the refractive index, glossiness and colorability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 12
Put 230 parts by mass of butyl acetate in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and 80 ° C. with stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to.

  Next, 10 parts by mass of azobisisobutyronitrile is added to the reaction vessel while maintaining a temperature of 80 ° C., and the azobisisobutyronitrile is dissolved in the contents in the reaction vessel. 50 parts by mass, 40 parts by mass of butyl methacrylate and 10 parts by mass of methacrylic acid were dropped into the reaction vessel over 3 hours. After completion of the dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having a carboxy group as a functional group. The obtained functional group-containing (meth) acrylate polymer had an acid value of 20 mgKOH / g and a weight average molecular weight of 6,300.

  100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above and 1.0 part by mass of dimethylbenzylamine were mixed, and the total amount (moles of functional groups of the functional group-containing (meth) acrylate polymer) ) And a bifunctional reaction type epoxy resin [manufactured by ADEKA, trade name: ADEKA GLYCIROL ED-503], the bifunctional reaction type epoxy so that the molar ratio is 1: 1. A clear coat composition was obtained by mixing a resin [trade name: Adekaglycilol ED-503, manufactured by ADEKA Corporation].

  As the physical properties of the clear coat composition obtained above, the refractive index, glossiness and colorability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 13
Put 230 parts by mass of butyl acetate in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and 80 ° C. with stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to.

  Next, 10 parts by mass of azobisisobutyronitrile was added to the reaction vessel while maintaining a temperature of 80 ° C., and the azobisisobutyronitrile was dissolved in the contents in the reaction vessel, and then polyethylene glycol. 20 parts by mass of monomethacrylate [manufactured by Nippon Emulsifier Co., Ltd., trade name: MA-50A] and 80 parts by mass of NFM were dropped into the reaction vessel over 3 hours. After completion of the dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having a hydroxyl group as a functional group. The obtained functional group-containing (meth) acrylate polymer had a hydroxyl value of 35 mgKOH / g and a weight average molecular weight of 6,000.

  Next, 100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above and 0.5 parts by mass of dibutyltin dilaurate are mixed, and the functional group-containing (meth) acrylate polymer has a functional group. A clear coat composition was obtained by mixing hexamethylene diisocyanate so that the molar ratio of the total amount (mol) to the total amount (mol) of the functional group of hexamethylene diisocyanate was 1: 1.

  As the physical properties of the clear coat composition obtained above, the refractive index, glossiness and colorability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 14
Put 230 parts by mass of butyl acetate in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and 80 ° C. with stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to.

  Next, 10 parts by mass of azobisisobutyronitrile is added to the reaction vessel while maintaining a temperature of 80 ° C., and the azobisisobutyronitrile is dissolved in the contents in the reaction vessel. 75 parts by mass of the obtained NFM and 25 parts by mass of 2-hydroxyethyl acrylate were dropped into the reaction vessel over 3 hours. After completion of the dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having a hydroxyl group as a functional group. The functional group-containing (meth) acrylate polymer thus obtained had a hydroxyl value of 121 mgKOH / g and a weight average molecular weight of 6200, and the glass transition temperature of the coating film of the test piece prepared in the same manner as described above was 90 ° C. It was.

  100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above and 20 parts by mass of a methyl ethyl ketone dispersion of zirconia filler (average particle diameter of zirconia filler: 10 nm, content of zirconia filler: 30% by mass) , 0.5 parts by mass of dibutyltin dilaurate is mixed, and the molar ratio of the total amount (mol) of the functional group of the functional group-containing (meth) acrylate polymer to the total amount (mol) of the functional group of hexamethylene diisocyanate is A clear coat composition was obtained by mixing hexamethylene diisocyanate so as to be 1: 1.

  As the physical properties of the clear coat composition obtained above, the refractive index, glossiness and colorability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 15
Put 230 parts by mass of butyl acetate in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and 80 ° C. with stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to.

  Next, 10 parts by mass of azobisisobutyronitrile was added to the reaction vessel while maintaining the temperature at 80 ° C., and the azobisisobutyronitrile was dissolved in the contents in the reaction vessel. 30 parts by mass of anthrylmethyl methacrylate, 45 parts by mass of styrene and 25 parts by mass of 2-hydroxyethyl acrylate were dropped into the reaction vessel over 3 hours. After completion of the dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having a hydroxyl group as a functional group. The obtained functional group-containing (meth) acrylate polymer has a hydroxyl value of 121 mgKOH / g and a weight average molecular weight of 4500. The glass transition temperature of the coating film of the test piece prepared in the same manner as described above has high hardness. Therefore, it could not be measured.

  100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above and 0.5 part by mass of dibutyltin dilaurate are mixed, and the total amount of functional groups (mol) of the functional group-containing (meth) acrylate polymer. ) And hexamethylene diisocyanate were mixed so that the molar ratio of the functional group of hexamethylene diisocyanate to the total amount (mole) was 1: 1 to obtain a clear coat composition.

  As the physical properties of the clear coat composition obtained above, the refractive index, glossiness and colorability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 16
Put 230 parts by mass of cyclopentanone in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and under stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to ° C.

  Next, 10 parts by mass of azobisisobutyronitrile was added to the reaction vessel while maintaining the temperature at 80 ° C., and the azobisisobutyronitrile was dissolved in the contents in the reaction vessel. 55 parts by mass of anthrylmethyl methacrylate, 20 parts by mass of benzyl methacrylate and 25 parts by mass of 2-hydroxyethyl acrylate were dropped into the reaction vessel over 3 hours. After completion of the dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having a hydroxyl group as a functional group. The obtained functional group-containing (meth) acrylate polymer has a hydroxyl value of 121 mgKOH / g and a weight average molecular weight of 5000, and the glass transition temperature hardness of the coating film of the test piece prepared in the same manner as described above is determined by the hardness. It was not possible to measure because of its high value.

  100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above and 0.5 part by mass of dibutyltin dilaurate are mixed, and the total amount of functional groups (mol) of the functional group-containing (meth) acrylate polymer. ) And hexamethylene diisocyanate were mixed so that the molar ratio of the functional group of hexamethylene diisocyanate to the total amount (mole) was 1: 1 to obtain a clear coat composition.

  As the physical properties of the clear coat composition obtained above, the refractive index, glossiness and colorability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 17
Put 230 parts by mass of cyclopentanone in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and under stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to ° C.

  Next, 10 parts by mass of azobisisobutyronitrile is added to the reaction vessel while maintaining a temperature of 80 ° C., and the azobisisobutyronitrile is dissolved in the contents in the reaction vessel. 75 parts by mass of the obtained NFM and 25 parts by mass of 2-hydroxyethyl acrylate were dropped into the reaction vessel over 3 hours. After completion of the dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having a hydroxyl group as a functional group. The functional group-containing (meth) acrylate polymer thus obtained had a hydroxyl value of 121 mgKOH / g and a weight average molecular weight of 6200, and the glass transition temperature of the coating film of the test piece prepared in the same manner as described above was 90 ° C. It was.

  100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above and 0.5 part by mass of dibutyltin dilaurate are mixed, and the total amount of functional groups (mol) of the functional group-containing (meth) acrylate polymer. ) And hexamethylene diisocyanate were mixed so that the molar ratio of the functional group of hexamethylene diisocyanate to the total amount (mole) was 1: 1 to obtain a clear coat composition.

  As the physical properties of the clear coat composition obtained above, the refractive index, glossiness and colorability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 18
Put 230 parts by mass of cyclopentanone in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and under stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to ° C.

  Next, 10 parts by mass of azobisisobutyronitrile is added to the reaction vessel while maintaining a temperature of 80 ° C., and the azobisisobutyronitrile is dissolved in the contents in the reaction vessel. 75 parts by mass of the obtained NFM and 25 parts by mass of 4-hydroxyptyl acrylate were dropped into the reaction vessel over 3 hours. After completion of the dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having a hydroxyl group as a functional group. The functional group-containing (meth) acrylate polymer thus obtained had a hydroxyl value of 121 mgKOH / g and a weight average molecular weight of 6000. The glass transition temperature of the coating film of the test piece prepared in the same manner as described above was 80 ° C. It was.

  100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above and 0.5 part by mass of dibutyltin dilaurate are mixed, and the total amount of functional groups (mol) of the functional group-containing (meth) acrylate polymer. ) And hexamethylene diisocyanate were mixed so that the molar ratio of the functional group of hexamethylene diisocyanate to the total amount (mole) was 1: 1 to obtain a clear coat composition.

  As the physical properties of the clear coat composition obtained above, the refractive index, glossiness and colorability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 19
Put 230 parts by mass of cyclopentanone in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and under stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to ° C.

  Next, 10 parts by mass of azobisisobutyronitrile was added to the reaction vessel while maintaining a temperature of 80 ° C., and the azobisisobutyronitrile was dissolved in the contents in the reaction vessel, and then polyethylene glycol. 20 parts by mass of monomethacrylate [manufactured by Nippon Emulsifier Co., Ltd., trade name: MA-50A] and 80 parts by mass of NFM were dropped into the reaction vessel over 3 hours. After completion of the dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having a hydroxyl group as a functional group. The obtained functional group-containing (meth) acrylate polymer had a hydroxyl value of 35 mgKOH / g and a weight average molecular weight of 6,000.

  Next, 100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above and 0.5 parts by mass of dibutyltin dilaurate are mixed, and the functional group-containing (meth) acrylate polymer has a functional group. A clear coat composition was obtained by mixing hexamethylene diisocyanate so that the molar ratio of the total amount (mol) to the total amount (mol) of the functional group of hexamethylene diisocyanate was 1: 1.

  As the physical properties of the clear coat composition obtained above, the refractive index, glossiness and colorability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 20
Put 230 parts by mass of cyclopentanone in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and under stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to ° C.

  Next, 10 parts by mass of azobisisobutyronitrile is added to the reaction vessel while maintaining a temperature of 80 ° C., and the azobisisobutyronitrile is dissolved in the contents in the reaction vessel. 75 parts by mass of the obtained NFM and 25 parts by mass of 2-hydroxyethyl acrylate were dropped into the reaction vessel over 3 hours. After completion of the dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having a hydroxyl group as a functional group. The functional group-containing (meth) acrylate polymer thus obtained had a hydroxyl value of 121 mgKOH / g and a weight average molecular weight of 6200, and the glass transition temperature of the coating film of the test piece prepared in the same manner as described above was 90 ° C. It was.

  100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above and 20 parts by mass of a methyl ethyl ketone dispersion of zirconia filler (average particle diameter of zirconia filler: 10 nm, content of zirconia filler: 30% by mass) , 0.5 parts by mass of dibutyltin dilaurate is mixed, and the molar ratio of the total amount (mol) of the functional group of the functional group-containing (meth) acrylate polymer to the total amount (mol) of the functional group of hexamethylene diisocyanate is A clear coat composition was obtained by mixing hexamethylene diisocyanate so as to be 1: 1.

  As the physical properties of the clear coat composition obtained above, the refractive index, glossiness and colorability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1
Put 230 parts by mass of butyl acetate in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and 80 ° C. with stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to.

  Next, 10 parts by mass of azobisisobutyronitrile is added to the reaction vessel while maintaining a temperature of 80 ° C., and the azobisisobutyronitrile is dissolved in the contents in the reaction vessel. 7 parts by mass, 70 parts by mass of n-butyl methacrylate and 25 parts by mass of 2-hydroxyethyl acrylate were dropped into the reaction vessel over 3 hours. After completion of the dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having a hydroxyl group as a functional group. The obtained functional group-containing (meth) acrylate polymer had a hydroxyl value of 121 mgKOH / g.

  By dispersing 30 parts by mass of metal fine particles [manufactured by Nissan Chemical Industries, Ltd., trade name: Nanouse OZ-30M] in 100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above, a clear coat composition is obtained. I got a thing.

  As the physical properties of the clear coat composition obtained above, the refractive index, glossiness and colorability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2
Put 230 parts by mass of cyclopentanone in a reaction vessel equipped with a stirrer, a nitrogen gas introduction tube, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, and under stirring while introducing nitrogen gas into the reaction vessel. The temperature was raised to ° C.

  Next, 10 parts by mass of azobisisobutyronitrile is added to the reaction vessel while maintaining a temperature of 80 ° C., and the azobisisobutyronitrile is dissolved in the contents in the reaction vessel. 7 parts by mass, 70 parts by mass of n-butyl methacrylate and 25 parts by mass of 2-hydroxyethyl acrylate were dropped into the reaction vessel over 3 hours. After completion of the dropping, the contents of the reaction vessel were maintained at 80 ° C. for 4 hours to obtain a functional group-containing (meth) acrylate polymer having a hydroxyl group as a functional group. The obtained functional group-containing (meth) acrylate polymer had a hydroxyl value of 121 mgKOH / g.

  By dispersing 30 parts by mass of metal fine particles [manufactured by Nissan Chemical Industries, Ltd., trade name: Nanouse OZ-30M] in 100 parts by mass of the functional group-containing (meth) acrylate polymer obtained above, a clear coat composition is obtained. I got a thing.

  As the physical properties of the clear coat composition obtained above, the refractive index, glossiness and colorability were evaluated in the same manner as in Example 1. The results are shown in Table 1.

  From the above results, the clear coat composition obtained in each example has low colorability, has a high refractive index without using a filler, and is glossy even when a filler is used. It turns out that it is excellent and can be applied to a thick film. From the comparison between Example 7 and Example 14, when the filler is used as in Example 14, the refractive index of the coating film can be increased, and even if the filler is used, the glossiness is enhanced. It can be seen that it is excellent and can be applied to a thick film.

  The clear coat composition of the present invention is coated, for example, on the outer panel of automobile bodies such as passenger cars, trucks, motorcycles, buses, etc., and on the outer panels of household electrical products such as automobile parts, electronic devices, mobile phones, and audio devices. In particular, it is expected to be used for objects to be coated such as outer panels of automobile bodies and automobile parts.

Claims (2)

A clearcoat composition for use in a topcoat comprising (A) an aromatic ring-containing (meth) acrylate and formula (I):

[Wherein, R ¹ is a hydrogen atom or a methyl group, R ² is a hydroxyl group, a C 1-4 alkyl group having a hydroxyl group, a carboxyl group, a C 1-4 alkyl group having a carboxyl group, an epoxy group or an epoxy. An alkyl group having 1 to 4 carbon atoms having a group, a hydroxyalkyloxycarbonyl group having 1 to 4 carbon atoms of a hydroxyalkyl group, or a formula:

(Wherein n represents an integer of 3 to 20)
A clear coat composition comprising a functional group-containing (meth) acrylate polymer obtained by polymerizing a monomer component containing a functional group-containing monomer represented by formula (B), and (B) a crosslinking agent. .   Furthermore, the clearcoat composition of Claim 1 containing the filler whose average particle diameter is 3-30 nm in the quantity of 0-25 mass parts per 100 mass parts of functional group containing (meth) acrylate type polymers.