JP2017179314A - Aqueous resin composition for top coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous resin composition for top coating forming a coated film excellent in low temperature film deposition stability even when a large amount of an inorganic filler is contained without using a large amount of film deposition assistant, and forming a coated film excellent in hot water whitening resistance, adhesiveness, fingerprint resistance and coated film extensibility.SOLUTION: There is provided an aqueous resin composition used for top coating, containing emulsion particles and an inorganic filler, percentage content of the inorganic filler in the total solid component of the emulsion particles and the inorganic filler is 50 to 90 mass% and a monomer component used as a raw material of the emulsion particles contains a styrene monomer of 30 to 70 mass%.SELECTED DRAWING: None

Description

  The present invention relates to an aqueous resin composition for top coating. More specifically, the present invention is suitable for use in, for example, a top coating material that can be suitably used for a top coating material called a top coat that is applied to the surface of a building interior material, etc. The present invention relates to a water-based resin composition for top coating and a method for producing the same.

  In recent years, in order to avoid environmental problems caused by the release of volatile organic compounds into the atmosphere, water-based paints using water-dispersible resins such as water-soluble resins and emulsions have been used instead of solvent-based paints. . However, water-based paints are generally inferior in water resistance, weather resistance, etc. compared to organic solvent-based paints due to the use of water as a solvent. May deteriorate.

  As an aqueous resin dispersion that prevents deterioration of the coating film due to contact with water and is excellent in weather resistance, an aqueous resin dispersion containing a polymer that is essentially used as an aromatic monomer unit has been proposed. (For example, refer to Patent Document 1).

  The aqueous resin dispersion is coated with water that causes deterioration of the coating film by making the polymerization conditions hydrophobic when polymerizing using a large amount of a polymerizable unsaturated bond group-containing aromatic compound such as styrene. Since it is prevented from entering the film and the formed coating film is excellent in weather resistance, it can be used for undercoating, intermediate coating, and overcoating of building materials, for example.

  However, when a large amount of an inorganic filler is added to the aqueous resin dispersion in order to improve the design properties of the coating film, the low-temperature film-forming stability of the coating film to be formed is lowered. When a large amount of the film-forming aid is used, the ambient environment is deteriorated due to volatilization of the film-forming aid from the formed coating film. Therefore, a large amount of film forming aid cannot be used.

  Therefore, in recent years, it is suitable for a top coating material that can form a coating film excellent in low-temperature film-forming stability even if a large amount of an inorganic filler is contained without using a large amount of a film forming auxiliary, and suitable for the top coating material. Development of a water-based resin composition for top coating that can be used in the field is desired.

Japanese Patent No. 5258141

  The present invention has been made in view of the prior art, and forms a coating film excellent in low-temperature film-forming stability even when a large amount of an inorganic filler is contained without using a large amount of a film-forming auxiliary. In addition, the present invention provides a top coating composition that forms a coating film excellent in warm water whitening resistance, adhesion, fingerprint resistance, and coating film stretchability, and an aqueous resin composition for top coating composition that can be suitably used for the top coating composition. The task is to do.

The present invention
(1) An aqueous resin composition used for a top coating, which contains emulsion particles and an inorganic filler, and the content of the inorganic filler in the total solid content of the emulsion particles and the inorganic filler is 50 to 90% by mass. An aqueous resin composition for top coating, wherein the monomer component used as a raw material for the emulsion particles contains 30 to 70% by mass of a styrene monomer;
(2) A method for producing an aqueous resin composition for use in a top coating, which comprises emulsion polymerization of a monomer component containing 30 to 70% by mass of a styrene monomer and contains the resulting emulsion particles When mixing the resin emulsion and the inorganic filler, the content of the inorganic filler in the total solid content of the emulsion particles and the inorganic filler is adjusted to 50 to 90% by mass, and the aqueous resin composition for topcoat paint And (3) a top coating composition comprising the aqueous resin composition for top coating composition described in (1) above.

  According to the present invention, a coating film excellent in low-temperature film-forming stability can be formed even when a large amount of an inorganic filler is contained without using a large amount of a film forming auxiliary, and hot water whitening resistance and adhesion are There are provided a top coating composition which forms a coating film excellent in fingerprint resistance and coating film stretchability, and an aqueous resin composition for top coating composition which can be suitably used for the top coating composition.

  As described above, the aqueous resin composition for topcoat paint of the present invention contains emulsion particles and an inorganic filler, and the content of the inorganic filler in the total solid content of the emulsion particles and the inorganic filler is 50 to 90% by mass. The monomer component used as a raw material for the emulsion particles contains 30 to 70% by mass of a styrene monomer.

  Since the aqueous resin composition for topcoat paints of the present invention has the above-mentioned constituent requirements, by using the resin composition, a large amount of an inorganic filler can be contained without using a large amount of a film forming auxiliary. In addition, it is possible to obtain a top coating composition which forms a coating film excellent in low-temperature film-forming stability and forms a coating film excellent in hot water whitening resistance, adhesion, fingerprint resistance and coating film extensibility.

  The aqueous resin composition for topcoat paints of the present invention includes, for example, a resin emulsion and an inorganic filler containing emulsion particles obtained by emulsion polymerization of a monomer component containing 30 to 70% by mass of a styrene monomer. Can be obtained by adjusting the content of the inorganic filler in the total solid content of the emulsion particles and the inorganic filler to 50 to 90% by mass.

  A monomer component containing a styrenic monomer is used as a raw material for the emulsion particles contained in the aqueous resin composition for topcoats of the present invention.

  Examples of the styrenic monomer include styrene, α-methylstyrene, p-methylstyrene, tert-methylstyrene, chlorostyrene, vinyltoluene, and the like, but the present invention is limited only to such examples. is not. These styrenic monomers may be used alone or in combination of two or more. Styrene monomers have functional groups such as alkyl groups such as methyl and tert-butyl groups, nitro groups, nitrile groups, alkoxyl groups, acyl groups, sulfone groups, hydroxyl groups, and halogen atoms in the benzene ring. May be. Among these styrenic monomers, a coating film excellent in low-temperature film-forming stability can be formed even if a large amount of inorganic filler is contained without using a large amount of film-forming auxiliary, Styrene is preferred from the viewpoint of obtaining a top coating composition that forms a coating film excellent in whitening, adhesion, fingerprint resistance and coating film extensibility.

  The content of the styrenic monomer in the monomer component forms a coating film that has excellent low-temperature film-forming stability even when a large amount of inorganic filler is contained without using a large amount of film-forming auxiliary. In addition, from the viewpoint of obtaining a top coating composition that forms a coating film excellent in warm water whitening resistance, adhesion, fingerprint resistance and coating film stretchability, it is 30% by mass or more, preferably 35% by mass or more. Without using a large amount of an agent, even if a large amount of an inorganic filler is contained, a coating film excellent in low-temperature film-forming stability is formed and a top coating material that forms a coating film excellent in coating film extensibility is obtained. From the viewpoint, it is 70% by mass or less, preferably 65% by mass or less.

  As the monomer component, a monomer other than the styrene monomer (hereinafter simply referred to as “other monomer”) can be used.

  Other monomers include, for example, alkyl (meth) acrylates, carboxyl group-containing monomers, hydroxyl group-containing (meth) acrylates, silane group-containing monomers, nitrogen atom-containing monomers, and styrene monomers Aromatic monomers, oxo group-containing monomers, fluorine atom-containing monomers, epoxy group-containing monomers, UV-absorbing monomers, UV-stable monomers, and the like. Is not limited to such examples. These monomers may be used alone or in combination of two or more. Among these other monomers, a coating film excellent in low-temperature film-forming stability can be formed without using a large amount of a film-forming auxiliary, and even if it contains a large amount of inorganic filler, From the viewpoint of obtaining a top coating composition that forms a coating film excellent in whitening, adhesion, fingerprint resistance, and coating film stretchability, alkyl (meth) acrylate, carboxyl group-containing monomer, hydroxyl group-containing (meth) acrylate, and silane Group-containing monomers are preferred.

  In the present specification, “(meth) acrylate” means “acrylate” or “methacrylate”, “(meth) acryl” means “acryl” or “methacryl”, and “(meth) acryloyl” means It means “acryloyl” or “methacryloyl”.

    Examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, and sec-butyl (meth). Alkyl having 1 to 18 carbon atoms in an ester group such as acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, n-octyl (meth) acrylate, tridecyl (meth) acrylate, n-lauryl (meth) acrylate Although (meth) acrylate etc. are mentioned, this invention is not limited only to this illustration. These alkyl (meth) acrylates may be used alone or in combination of two or more. Among these alkyl (meth) acrylates, a coating film excellent in low-temperature film-forming stability can be formed even if a large amount of inorganic filler is contained without using a large amount of film forming auxiliary, Alkyl (meth) acrylates having 1 to 8 carbon atoms in the alkyl group are preferred from the viewpoint of obtaining a top coating composition that forms a coating film excellent in whitening, adhesion, fingerprint resistance, and coating film extensibility. More preferred are (meth) acrylate, n-butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, and further preferred are methyl methacrylate, n-butyl acrylate and 2-ethylhexyl acrylate.

  The content of the alkyl (meth) acrylate in the monomer component forms a coating film having excellent low-temperature film-forming stability even when a large amount of inorganic filler is contained without using a large amount of film forming aid. In addition, from the viewpoint of obtaining a top coating that forms a coating film excellent in warm water whitening resistance, adhesion, fingerprint resistance, and coating film extensibility, it is preferably 20% by mass or more, more preferably 25% by mass or more, and still more preferably. Is 30% by mass or more, and without using a large amount of film-forming auxiliary, forms a coating film having excellent low-temperature film-forming stability even when containing a large amount of inorganic filler, From the viewpoint of obtaining a top coating composition that forms a coating film excellent in adhesion, fingerprint resistance and coating film extensibility, it is preferably 65% by mass or less.

  Examples of the carboxyl group-containing monomer include (meth) acrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, maleic anhydride, and other carboxyl group-containing aliphatic monomers. The invention is not limited to such examples. These carboxyl group-containing monomers may be used alone or in combination of two or more. Among these carboxyl group-containing monomers, a coating film excellent in low-temperature film-forming stability can be formed without using a large amount of a film-forming auxiliary, and even if a large amount of an inorganic filler is contained. (Meth) acrylic acid is preferred from the viewpoint of obtaining a top coating composition that forms a coating film excellent in warm water whitening, adhesion, fingerprint resistance, and coating film extensibility.

  The content of the carboxyl group-containing monomer in the monomer component allows the formation of a coating film with excellent low-temperature film-forming stability even when a large amount of inorganic filler is contained without using a large amount of film-forming aid. In addition, from the viewpoint of obtaining a top coating composition that forms a coating film excellent in warm water whitening resistance, adhesion, fingerprint resistance, and coating film extensibility, preferably 0.1% by mass or more, more preferably 0.2% by mass. % Or more, more preferably 0.3% by mass or more, and without using a large amount of film forming aid, a coating film having excellent low-temperature film-forming stability can be formed even if a large amount of inorganic filler is contained. In addition, from the viewpoint of obtaining a top coating material that forms a coating film excellent in warm water whitening resistance, adhesion, fingerprint resistance, and coating film extensibility, it is preferably 5% by mass or less, more preferably 3% by mass or less, and still more preferably. Is 2% by mass or less.

  Examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4-hydroxy Examples include hydroxyl group-containing (meth) acrylates having 1 to 18 carbon atoms in the ester group such as butyl (meth) acrylate, but the present invention is not limited to such examples. These hydroxyl group-containing (meth) acrylates may be used alone or in combination of two or more. Among these hydroxyl group-containing (meth) acrylates, a coating film excellent in low-temperature film-forming stability can be formed even if a large amount of inorganic filler is contained without using a large amount of film-forming auxiliary. From the viewpoint of obtaining a top coating composition that forms a coating film excellent in warm water whitening, adhesion, fingerprint resistance and coating film extensibility, 2-hydroxyethyl (meth) acrylate is preferable, and 2-hydroxyethyl methacrylate is more preferable.

  The content of the hydroxyl group-containing (meth) acrylate in the monomer component forms a coating film with excellent low-temperature film-forming stability even when a large amount of inorganic filler is contained without using a large amount of film-forming auxiliary. In addition, from the viewpoint of obtaining a top coating material that forms a coating film excellent in hot water whitening resistance, adhesion, fingerprint resistance and coating film extensibility, it is preferably 0.5% by mass or more, more preferably 1% by mass or more. More preferably, it is 1.5% by mass or more, and without using a large amount of film-forming auxiliary, even when a large amount of inorganic filler is contained, a coating film excellent in low-temperature film-forming stability is formed, From the viewpoint of obtaining a top coating material that forms a coating film excellent in hot water whitening resistance, adhesion, fingerprint resistance and coating film extensibility, it is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 3%. It is below mass%.

  Examples of the silane group-containing monomer include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (methoxyethoxy) silane, γ- (meth) acryloyloxypropyltrimethoxysilane, 2-styrylethyltrimethoxysilane, vinyltri Examples include chlorosilane, γ- (meth) acryloyloxypropylhydroxysilane, and γ- (meth) acryloyloxypropylmethylhydroxysilane, but the present invention is not limited to such examples. These silane group-containing monomers may be used alone or in combination of two or more. Among these silane group-containing monomers, a coating film excellent in low-temperature film-forming stability can be formed even if a large amount of inorganic filler is contained without using a large amount of film-forming auxiliary. From the viewpoint of obtaining a top coating material that forms a coating film excellent in warm water whitening, adhesion, fingerprint resistance, and coating film stretchability, γ- (meth) acryloyloxypropyltrimethoxysilane is preferred, and γ-methacryloyloxypropyltri Methoxysilane is more preferred.

  The content of the silane group-containing monomer in the monomer component forms a coating film with excellent low-temperature film-forming stability even when a large amount of inorganic filler is contained without using a large amount of film-forming auxiliary. In addition, from the viewpoint of obtaining a top coating composition that forms a coating film excellent in hot water whitening resistance, adhesion, fingerprint resistance, and coating film extensibility, preferably 0.01% by mass or more, more preferably 0.05% by mass. % Or more, more preferably 0.1% by mass or more, and a coating film excellent in low-temperature film-forming stability can be formed even if a large amount of inorganic filler is contained without using a large amount of film forming auxiliary. In addition, from the viewpoint of obtaining a top coating composition that forms a coating film excellent in hot water whitening resistance and coating film extensibility, it is preferably 5% by mass or less, more preferably 3% by mass or less, and further preferably 2% by mass or less. .

  Examples of the nitrogen atom-containing monomer include (meth) acrylamide, diacetone (meth) acrylamide, N-monomethyl (meth) acrylamide, N-monoethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N -N-propyl (meth) acrylamide, N-isopropyl (meth) acrylamide, methylenebis (meth) acrylamide, N-methylol (meth) acrylamide, N-butoxymethyl (meth) acrylamide, dimethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, (meth) acrylamide compounds such as diacetone (meth) acrylamide, nitrogen such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate Child-containing (meth) acrylate compounds, N- vinylpyrrolidone, but like (meth) acrylonitrile, the present invention is not limited only to those exemplified. These nitrogen atom-containing monomers may be used alone or in combination of two or more.

  Examples of the aromatic monomer other than the styrene monomer include aralkyl (meth) acrylate, but the present invention is not limited to such examples. Examples of the aralkyl (meth) acrylate include aralkyl having 7 to 18 carbon atoms such as benzyl (meth) acrylate, phenylethyl (meth) acrylate, methylbenzyl (meth) acrylate, naphthylmethyl (meth) acrylate and the like. Although (meth) acrylate etc. are mentioned, this invention is not limited only to this illustration. These aromatic monomers other than the styrene monomer may be used alone or in combination of two or more.

  Examples of the oxo group-containing monomer include (di) ethylene glycol (methoxy) (meta) such as ethylene glycol (meth) acrylate, ethylene glycol methoxy (meth) acrylate, diethylene glycol (meth) acrylate, and diethylene glycol methoxy (meth) acrylate. ) Acrylate and the like, but the present invention is not limited to such examples. These oxo group-containing monomers may be used alone or in combination of two or more.

  Examples of the fluorine atom-containing monomer include fluorine atom-containing alkyl having 2 to 6 carbon atoms in an ester group such as trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, and octafluoropentyl (meth) acrylate. Although (meth) acrylate etc. are mentioned, this invention is not limited only to this illustration. These fluorine atom-containing monomers may be used alone or in combination of two or more.

  Examples of the epoxy group-containing monomer include epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate, but the present invention is not limited to such examples. These epoxy group-containing monomers may be used alone or in combination of two or more.

  Examples of the UV-absorbing monomer include benzotriazole-based UV-absorbing monomers and benzophenone-based UV-absorbing monomers, but the present invention is not limited to such examples. These ultraviolet absorbing monomers may be used alone or in combination of two or more.

  Examples of the benzotriazole-based UV-absorbing monomer include 2- [2′-hydroxy-5 ′-(meth) acryloyloxymethylphenyl] -2H-benzotriazole, 2- [2′-hydroxy-5′- (Meth) acryloyloxyethylphenyl] -2H-benzotriazole, 2- [2′-hydroxy-5 ′-(meth) acryloyloxymethylphenyl] -5-tert-butyl-2H-benzotriazole, 2- [2 ′ -Hydroxy-5 '-(meth) acryloylaminomethyl-5'-tert-octylphenyl] -2H-benzotriazole, 2- [2'-hydroxy-5'-(meth) acryloyloxypropylphenyl] -2H-benzo Triazole, 2- [2'-hydroxy-5 '-(meth) acryloyloxyhex Ruphenyl] -2H-benzotriazole, 2- [2′-hydroxy-3′-tert-butyl-5 ′-(meth) acryloyloxyethylphenyl] -2H-benzotriazole, 2- [2′-hydroxy-3 ′ -Tert-butyl-5 '-(meth) acryloyloxyethylphenyl] -5-chloro-2H-benzotriazole, 2- [2'-hydroxy-5'-tert-butyl-3'-(meth) acryloyloxyethyl Phenyl] -2H-benzotriazole, 2- [2′-hydroxy-5 ′-(meth) acryloyloxyethylphenyl] -5-chloro-2H-benzotriazole, 2- [2′-hydroxy-5 ′-(meta ) Acrylyloxyethylphenyl] -5-cyano-2H-benzotriazole, 2- [2'-hydride Xyl-5 ′-(meth) acryloyloxyethylphenyl] -5-tert-butyl-2H-benzotriazole, 2- [2′-hydroxy-5 ′-(β- (meth) acryloyloxyethoxy) -3′- tert-butylphenyl] -4-tert-butyl-2H-benzotriazole and the like, but the present invention is not limited to such examples. These benzotriazole-based UV-absorbing monomers may be used alone or in combination of two or more.

  Examples of the benzophenone-based UV-absorbing monomer include 2-hydroxy-4- (meth) acryloyloxybenzophenone, 2-hydroxy-4- [2-hydroxy-3- (meth) acryloyloxy] propoxybenzophenone, 2- Hydroxy-4- [2- (meth) acryloyloxy] ethoxybenzophenone, 2-hydroxy-4- [3- (meth) acryloyloxy-2-hydroxypropoxy] benzophenone, 2-hydroxy-3-tert-butyl-4- Examples include [2- (meth) acryloyloxy] butoxybenzophenone, but the present invention is not limited to such examples. These benzophenone-based ultraviolet absorbing monomers may be used alone or in combination of two or more.

  Examples of UV-stable monomers include 4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine, 4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine. 4- (meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloyl-1-methoxy-2,2,6,6-tetramethylpiperidine, 4-cyano- 4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-croto Noylamino-2,2,6,6-tetramethylpiperidine, 4- (meth) acryloylamino-1,2,2,6,6-pentamethylpiperidine, 4-sia -4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4-cyano- Examples include 4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine and the like. However, the present invention is not limited to such examples. These ultraviolet stable monomers may be used alone or in combination of two or more.

  The content of other monomers in the monomer component forms a coating film with excellent low-temperature film-forming stability even when a large amount of inorganic filler is contained without using a large amount of film forming aid. In addition, from the viewpoint of obtaining a top coating that forms a coating film excellent in warm water whitening resistance, adhesion, fingerprint resistance and coating film stretchability, preferably 30% by mass or more, more preferably 35% by mass or more, Without using a large amount of film forming aid, it forms a coating film with excellent low-temperature film-forming stability even when a large amount of inorganic filler is contained, and also has resistance to warm water whitening, adhesion, fingerprint resistance and coating. From the viewpoint of obtaining a top coating composition that forms a coating film excellent in film extensibility, it is preferably 70% by mass or less, more preferably 65% by mass or less.

  As a method for emulsion polymerization of the monomer component, for example, an aqueous medium containing a water-soluble organic solvent such as methanol and a lower alcohol, and water, an emulsifier is dissolved in a medium such as water, and a single amount is obtained under heating and stirring. A method of dropping a body component and a polymerization initiator, a method of dropping a monomer component previously emulsified with an emulsifier and water, into water or an aqueous medium, and the like. It is not limited. In addition, what is necessary is just to set the quantity of a medium suitably in consideration of the non volatile matter amount contained in the resin emulsion obtained.

  Examples of the emulsifier include an anionic emulsifier, a nonionic emulsifier, a cationic emulsifier, an amphoteric emulsifier, and a polymer emulsifier. These emulsifiers may be used alone or in combination of two or more.

  Examples of the anionic emulsifier include alkyl sulfate salts such as ammonium dodecyl sulfate and sodium dodecyl sulfate; alkyl sulfonate salts such as ammonium dodecyl sulfonate and sodium dodecyl sulfonate; alkyl aryl sulfonate salts such as ammonium dodecyl benzene sulfonate and sodium dodecyl naphthalene sulfonate; Examples include polyoxyethylene alkyl sulfate salts; polyoxyethylene alkyl aryl sulfate salts; dialkyl sulfosuccinates; aryl sulfonic acid-formalin condensates; fatty acid salts such as ammonium laurate and sodium stearate. It is not limited to illustration only.

  Nonionic emulsifiers include, for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether, condensate of polyethylene glycol and polypropylene glycol, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, fatty acid monoglyceride, ethylene oxide and aliphatic Although the condensate with an amine etc. are mentioned, this invention is not limited only to this illustration.

  Examples of the cationic emulsifier include alkylammonium salts such as dodecylammonium chloride, but the present invention is not limited to such examples.

  Examples of amphoteric emulsifiers include betaine ester type emulsifiers, but the present invention is not limited to such examples.

  Examples of the polymer emulsifier include poly (meth) acrylates such as sodium polyacrylate; polyvinyl alcohol; polyvinyl pyrrolidone; polyhydroxyalkyl (meth) acrylates such as polyhydroxyethyl acrylate; single polymers constituting these polymers. Although the polymer etc. which use a 1 or more types of monomer of a monomer as a copolymerization component are mentioned, this invention is not limited only to this illustration.

  The reactive emulsifier does not use a large amount of film-forming auxiliary, and forms a coating film excellent in low-temperature film-forming stability even if it contains a large amount of inorganic filler, From the viewpoint of obtaining a top coating composition that forms a coating film excellent in fingerprint resistance and coating film extensibility, it can be suitably used. Among them, a non-nonylphenyl emulsifier is preferable from the viewpoint of environmental protection.

  Examples of the reactive emulsifier include propenyl-alkylsulfosuccinic acid ester salt, (meth) acrylic acid polyoxyethylene sulfonate salt, polyoxyethylene alkylpropenyl phenyl ether ammonium sulfate [for example, trade name: manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Aqualon HS-10, Aqualon BC-10, etc.], sulfonate salts of allyloxymethylalkyloxypolyoxyethylene (for example, Dairon Kogyo Seiyaku Co., Ltd., trade name: Aqualon KH-10, etc.), allyloxymethylnonylphenoxy Sulphonate salt of ethyl hydroxypolyoxyethylene [for example, manufactured by ADEKA, trade name: Adekaria soap SE-10, etc.], allyloxymethylalkoxyethyl hydroxypolyoxyethylene sulfate salt [for example, (strain Made by ADEKA, trade names: Adekari Soap SR-10, SR-30, etc.], bis (polyoxyethylene polycyclic phenyl ether) methacrylated sulfonate salt [for example, manufactured by Nippon Emulsifier Co., Ltd., trade name: Antox MS- 60, etc.], allyloxymethylalkoxyethylhydroxypolyoxyethylene [for example, manufactured by ADEKA, trade name: Adekaria soap ER-20, etc.], polyoxyethylene alkylpropenyl phenyl ether [for example, Daiichi Kogyo Seiyaku Co., Ltd. Product name: Aqualon RN-20, etc.], allyloxymethylnonylphenoxyethylhydroxypolyoxyethylene [for example, product made by ADEKA, product name: Adecalia Soap NE-10, etc.] The invention is limited to only such examples No. Any of these reactive emulsifiers may be used alone or in combination of two or more.

  The amount of the emulsifier per 100 parts by mass of the monomer component is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and further preferably 5 parts by mass or more, from the viewpoint of improving the polymerization stability. Without using a large amount of auxiliaries, even if a large amount of inorganic filler is contained, it forms a coating film with excellent low-temperature film-forming stability, as well as warm water whitening resistance, adhesion, fingerprint resistance, and coating film stretching. From the viewpoint of obtaining a top coating composition that forms a coating film having excellent properties, it is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and still more preferably 10 parts by mass or less.

  A polymerization initiator can be used when the monomer component is polymerized. Examples of the polymerization initiator include azobisisobutyronitrile, 2,2-azobis (2-methylbutyronitrile), 2,2-azobis (2,4-dimethylvaleronitrile), 2,2-azobis ( Azo compounds such as 2-diaminopropane) hydrochloride, 4,4-azobis (4-cyanovaleric acid), 2,2-azobis (2-methylpropionamidine); persulfates such as potassium persulfate and ammonium persulfate; Examples of the peroxide include peroxides such as hydrogen peroxide, benzoyl peroxide, parachlorobenzoyl peroxide, lauroyl peroxide, and ammonium peroxide. However, the present invention is not limited to such examples. These polymerization initiators may be used alone or in combination of two or more.

  The amount of the polymerization initiator per 100 parts by mass of the monomer component is preferably 0.01 parts by mass or more, more preferably 0 from the viewpoint of increasing the polymerization rate and reducing the residual amount of the unreacted monomer component. 0.03 parts by mass or more, without using a large amount of film forming aid, and forming a coating film excellent in low-temperature film-forming stability even when containing a large amount of inorganic filler, From the viewpoint of obtaining a top coating composition that forms a coating film excellent in adhesion, fingerprint resistance and coating film extensibility, it is preferably 10 parts by mass or less, more preferably 5 parts by mass or less.

  The method for adding the polymerization initiator is not particularly limited. Examples of the addition method include batch charging, divided charging, and continuous dripping. From the viewpoint of advancing the completion time of the polymerization reaction, a part of the polymerization initiator may be added to the flask before or after the monomer component is added to the reaction system.

  In order to accelerate the decomposition of the polymerization initiator, for example, a reducing agent such as sodium bisulfite and a polymerization initiator decomposition agent such as transition metal salt such as ferrous sulfate are added in an appropriate amount to the reaction system. Also good.

  In addition, if necessary, additives such as chain transfer agents such as compounds having a thiol group such as tert-dodecyl mercaptan, pH buffering agents, chelating agents may be added to the reaction system in appropriate amounts. Good. Since the amount of the additive varies depending on the type, it cannot be determined unconditionally, but is usually preferably 0.01 to 5 parts by mass, more preferably 0.1 to 3 parts per 100 parts by mass of the monomer component. Part by mass.

  The atmosphere for emulsion polymerization of the monomer component is not particularly limited, but is preferably an inert gas such as nitrogen gas from the viewpoint of increasing the efficiency of the polymerization initiator.

  Although the polymerization temperature at the time of carrying out emulsion polymerization of a monomer component does not have limitation, Usually, Preferably it is 50-100 degreeC, More preferably, it is 60-95 degreeC. The polymerization temperature may be constant or may be changed during the polymerization reaction.

  The polymerization time for emulsion polymerization of the monomer component is not particularly limited and may be appropriately set according to the progress of the polymerization reaction, but is usually about 2 to 9 hours.

  By emulsion polymerization of the monomer component as described above, a resin emulsion containing emulsion particles can be obtained.

  The polymer constituting the emulsion particles may have a crosslinked structure. The weight average molecular weight of the polymer, without using a large amount of film-forming auxiliary, forms a coating film with excellent low-temperature film-forming stability even if it contains a large amount of inorganic filler, From the viewpoint of obtaining a top coating composition that forms a coating film excellent in adhesion, fingerprint resistance and coating film extensibility, preferably 100,000 or more, more preferably 300,000 or more, further preferably 550,000 or more, particularly preferably 60. More than ten thousand. The upper limit of the weight average molecular weight of the polymer is not particularly limited because it is difficult to measure the weight average molecular weight when it has a cross-linked structure, but when it does not have a cross-linked structure, the film-forming property is improved. From the viewpoint, it is preferably 5 million or less.

  In addition, in this specification, the weight average molecular weight of a polymer uses gel permeation chromatography [manufactured by Tosoh Corporation, product number: HLC-8120GPC, column: TSKgel G-5000HXL and TSKgel GMHXL-L in series. ] Is used to mean the weight average molecular weight (in terms of polystyrene) measured.

  The emulsion particles contained in the resin emulsion form a coating film that has excellent low-temperature film-forming stability even when a large amount of inorganic filler is contained without using a large amount of film-forming auxiliary, and is also resistant to hot water whitening. From the viewpoint of obtaining a top coating composition that forms a coating film excellent in adhesion, fingerprint resistance and coating film extensibility, those having a plurality of resin layers prepared by multi-stage emulsion polymerization are preferred. When the emulsion particles have a plurality of resin layers, the boundary between the resin layers is not necessarily clear, and adjacent resin layers may be mixed with each other.

  The number of resin layers constituting the emulsion particles is such that a coating film excellent in low-temperature film-forming stability can be formed even if an inorganic filler is contained in a large amount without using a large amount of a film-forming auxiliary, From the viewpoint of obtaining a top coating composition that forms a coating film excellent in whitening, adhesion, fingerprint resistance, and coating film extensibility, it is preferably 2 to 5 layers, more preferably 2 and 3 layers.

  The monomer component used as the raw material of the resin layer present in the outermost layer of the emulsion particles having a plurality of resin layers may contain a large amount of inorganic filler without using a large amount of film forming aid. From the viewpoint of forming a coating film excellent in low-temperature film-forming stability and a top coating composition that forms a coating film excellent in hot water whitening resistance, adhesion, fingerprint resistance, and coating film stretchability. It is preferable that a monomer is contained. In this case, layers other than the outermost layer, for example, when the emulsion particles are formed of two resin layers, the inner layer, and when the emulsion particles are formed of three resin layers, the intermediate layer and the inner layer are The same kind of monomer as that used for the monomer component can be used. The emulsion particles can be prepared, for example, by subjecting the monomer component to multi-stage emulsion polymerization using the same polymerization method and polymerization conditions as in the case of emulsion polymerization of the monomer component.

  The content of the silane group-containing monomer in the monomer component used as the raw material for the resin layer present in the outermost layer of the emulsion particles contains a large amount of inorganic filler without using a large amount of film forming aid. It is preferable to obtain a top coating composition that forms a coating film excellent in low-temperature film-forming stability, and also forms a coating film excellent in hot water whitening resistance, adhesion, fingerprint resistance, and coating film extensibility. 0.01% by mass or more, more preferably 0.05% by mass or more, and still more preferably 0.1% by mass or more, and a large amount of inorganic filler is contained without using a large amount of film forming aid. From the viewpoint of forming a coating film excellent in low-temperature film-forming stability and obtaining a top coating composition that forms a coating film excellent in hot water whitening resistance and coating film extensibility, preferably 5% by mass or less, more preferably 3% by mass or less, more preferably It is 2 mass% or less.

  A monomer component containing a silane group-containing monomer as a raw material may be used only in the outermost layer, and a single component containing a silane group-containing monomer as a raw material in layers other than the outermost layer and the outermost layer. A monomer component may be used.

  When the emulsion particles have two resin layers, the mass ratio between the resin layer constituting the inner layer and the resin layer constituting the outer layer (resin constituting the inner layer / resin constituting the outer layer) Layer) does not use a large amount of film forming aid, and forms a coating film having excellent low-temperature film-forming stability even if it contains a large amount of inorganic filler, and also has a resistance to whitening with warm water, adhesion, From the viewpoint of obtaining a top coating material that forms a coating film excellent in fingerprint property and coating film extensibility, it is preferably 20/80 or more, more preferably 30/70 or more, and further preferably 40/60 or more. And from a viewpoint of improving adhesiveness, Preferably it is 80/20 or less, More preferably, it is 70/30 or less, More preferably, it is 60/40 or less.

  When the emulsion particles have three resin layers, a coating film excellent in low-temperature film-forming stability can be formed even if a large amount of inorganic filler is contained without using a large amount of film-forming aid. From the viewpoint of obtaining a top coat that forms a coating film excellent in warm water whitening, adhesion, fingerprint resistance, and coating film extensibility, the content of the resin layer constituting the inner layer (first layer) is 10 to 40. The content of the resin layer constituting the intermediate layer (second layer) between the inner layer and the outer layer is 20 to 60% by mass, and constitutes the outer layer (third layer). It is preferable that the content rate of a resin layer is 20-50 mass%.

  In emulsion particles having at least an inner layer and an outer layer resin layer, the glass transition temperature of either the inner layer or the outer layer is preferably −50 ° C. or higher, more preferably −45, from the viewpoint of improving fingerprint resistance. More than −40 ° C., more preferably −40 ° C. or more, and without using a large amount of film forming aid, even if a large amount of inorganic filler is contained, a coating film having excellent low-temperature film-forming stability is formed. From the viewpoint of obtaining a top coating composition that forms a coating film excellent in warm water whitening property, adhesion, and coating film extensibility, it is preferably 65 ° C. or less, more preferably 60 ° C. or less, and further preferably 55 ° C. or less. The glass transition temperature of the other resin layer is preferably −30 ° C. or higher, more preferably −25 ° C. or higher, and further preferably −20 ° C. or higher, from the viewpoint of improving fingerprint resistance. Forms a coating film with excellent low-temperature film-forming stability even when a large amount of inorganic filler is contained without using a large amount of coating material, and with excellent hot water whitening resistance, adhesion, and coating film extensibility From the viewpoint of obtaining a top coating composition that forms a film, it is preferably 15 ° C. or lower, more preferably 10 ° C. or lower, and further preferably 5 ° C. or lower.

  Further, the glass transition temperature of the whole emulsion particles is preferably −40 ° C. or higher, more preferably −30 ° C. or higher, and further preferably −20 ° C. or higher, from the viewpoint of improving fingerprint resistance. Without using a large amount, a coating film with excellent low-temperature film-forming stability can be formed even when a large amount of inorganic filler is contained, and a coating film with excellent hot water whitening resistance, adhesion, and coating film extensibility. From the viewpoint of obtaining a top coating to be formed, it is preferably 35 ° C. or lower, more preferably 30 ° C. or lower, even more preferably 25 ° C. or lower, still more preferably 20 ° C. or lower, from the viewpoint of further improving the low-temperature film-forming stability. Still more preferably, it is 0 ° C. or lower.

  The glass transition temperature of the resin layer constituting the emulsion particles can be easily adjusted by adjusting the type and amount of the monomer used for the monomer component. In consideration of the glass transition temperature of the resin layer constituting the emulsion particles, the composition of the monomer component used as a raw material for the resin layer constituting the emulsion particles can be determined.

In the present specification, the glass transition temperature of the resin layer constituting the emulsion particles is determined by using the glass transition temperature of the monomer homopolymer used in the monomer component constituting the polymer, formula:
1 / Tg = Σ (Wm / Tgm) / 100
[Wherein Wm represents the content (% by mass) of the monomer m in the monomer component constituting the polymer, and Tgm represents the glass transition temperature (absolute temperature: K) of the homopolymer of the monomer m. ]
The temperature calculated | required based on the Formula of Fox (Fox) represented by these.

  In this specification, unless otherwise indicated, the glass transition temperature of the resin layer which comprises emulsion particles means the glass transition temperature calculated | required based on the said Fox (Fox). For example, the glass transition temperature of the entire resin layer constituting the emulsion particles having a plurality of resin layers corresponds to the mass fraction of each monomer in all monomer components used in the multistage emulsion polymerization. It means the glass transition temperature determined from the glass transition temperature of the homopolymer of the monomer. For monomers with unknown glass transition temperature, such as special monomers and polyfunctional monomers, the total amount of monomers with unknown glass transition temperature in the monomer component is the mass fraction. If it is 10% by mass or less, the glass transition temperature can be determined using only the monomer whose glass transition temperature is known. When the total amount of monomers with unknown glass transition temperature in the monomer component exceeds 10% by mass, the glass transition temperature of the polymer is determined by differential scanning calorimetry (DSC) or differential calorimetry. (DTA), thermomechanical analysis (TMA), etc.

  The glass transition temperature of the polymer is, for example, -70 ° C. for 2-ethylhexyl acrylate homopolymer, 100 ° C. for styrene homopolymer, 95 ° C. for acrylic acid homopolymer, and 130 for methacrylic acid homopolymer. ℃, n-butyl acrylate homopolymer -56 ℃, methyl methacrylate homopolymer 105 ℃, 2-hydroxyethyl methacrylate homopolymer 55 ℃, γ-methacryloyloxypropyltrimethoxysilane homopolymer Then, it is 70 degreeC.

  In addition, when the emulsion particles are composed of a plurality of resin layers, the solubility parameter (hereinafter also referred to as SP value) of the resin layer constituting the outer layer is larger than the SP value of the resin layer constituting the inner layer. High is preferable from the viewpoint of improving the flexibility and film-forming property of the coating film. Also, the difference (absolute value) between the SP value of the resin layer constituting the inner layer and the resin layer constituting the outer layer is large from the viewpoint of forming a layer separation structure in the emulsion particles. preferable.

  The SP value is a value defined by the regular solution theory introduced by Hildebrand, and is also a measure of the solubility of the binary solution. In general, substances having similar SP values tend to be mixed with each other. Therefore, the SP value is also a measure for judging the ease of mixing of the solute and the solvent.

  From the viewpoint of improving the mechanical stability of the emulsion particles themselves, the average particle diameter of the emulsion particles is preferably 50 nm or more, more preferably 100 nm or more, and an inorganic filler can be used without using a large amount of film forming aid. A coating film with excellent low-temperature film-forming stability can be formed even when a large amount of is added, and a top coating composition that forms a coating film with excellent hot water whitening resistance, adhesion, fingerprint resistance, and coating film elongation is obtained. From the viewpoint, it is preferably 300 nm or less, more preferably 200 nm or less.

  In the present specification, the average particle size of the emulsion particles is measured using a particle size distribution measuring instrument (manufactured by Particle Sizing Systems, trade name: NICOMP Model 380) by a dynamic light scattering method. It means the volume average particle diameter.

  The nonvolatile content in the resin emulsion is preferably 30% by mass or more, more preferably 40% by mass or more from the viewpoint of improving productivity, and preferably 70% by mass or less, more preferably from the viewpoint of improving handleability. 60% by mass or less.

The amount of non-volatile content in the resin emulsion was determined by weighing 1 g of the resin emulsion and drying it with a hot air dryer at a temperature of 110 ° C. for 1 hour.
[Non-volatile content in resin emulsion (mass%)]
= ([Residue mass] / [resin emulsion 1 g]) × 100
Means the value obtained based on

  In addition, the minimum film-forming temperature of the resin emulsion can form a coating film having excellent low-temperature film-forming stability even when a large amount of an inorganic filler is contained without using a large amount of film-forming auxiliary, From the viewpoint of obtaining a top coating composition which forms a coating film excellent in whitening, adhesion, fingerprint resistance and coating film extensibility, it is preferably 5 ° C. or less, more preferably 0 ° C. or less. The minimum film-forming temperature of the resin emulsion can be adjusted, for example, by adjusting the glass transition temperature of the entire emulsion particles or the glass transition temperature of the outermost resin layer.

  In this specification, the minimum film-forming temperature of the resin emulsion is such that the resin emulsion is applied on a glass plate placed on a thermal gradient tester with an applicator so that the thickness is 0.2 mm, and cracks are not generated. It means the temperature when it occurs.

  The aqueous resin composition for top coating of the present invention contains an inorganic filler. In the present invention, the content of the inorganic filler in the total solid content of the emulsion particles and the inorganic filler is 50 to 90% by mass, and a simple substance containing 30 to 70% by mass of a styrene monomer as a raw material for the emulsion particles. One major feature is that the monomer component is used.

  Since the aqueous resin composition for top coat paint of the present invention uses a monomer component containing 30 to 70% by mass of a styrene monomer as a raw material for emulsion particles, the total of emulsion particles and inorganic fillers is used. Despite the inorganic filler content in the solid content of 50 to 90% by mass, low-temperature film-forming stability can be achieved even if a large amount of inorganic filler is contained without using a large amount of film forming aid. In addition to forming an excellent coating film, it is possible to obtain a top coating composition that forms a coating film excellent in warm water whitening resistance, adhesion, fingerprint resistance, and coating film extensibility.

  Examples of the inorganic filler include alkali metal carbonates such as sodium carbonate, sodium hydrogen carbonate, potassium carbonate and potassium hydrogen carbonate; alkaline earth metal carbonates such as magnesium carbonate, calcium carbonate and barium carbonate; ammonium carbonate and hydrogen carbonate Carbonates such as ammonium carbonate such as ammonium, zinc oxide particles, aluminum oxide particles, magnesium oxide particles, beryllium oxide particles, calcium oxide particles, zirconium oxide particles, alumina particles, titanium dioxide particles, silica particles, magnesium hydroxide particles, Aluminum hydroxide particles, calcium silicate particles, aluminum silicate particles, silicon carbide particles, silicon nitride particles, boron nitride particles, calcium sulfate particles, barium sulfate particles, magnesium carbonate particles, glass particles, kaolin, talc, mica powder Metal particles, but and carbon black, the present invention is not limited only to those exemplified. These may be used alone or in combination of two or more. Among these inorganic fillers, a coating film excellent in low-temperature film-forming stability can be formed even if a large amount of inorganic filler is contained, without using a large amount of film forming auxiliary, and hot water whitening resistance From the viewpoint of obtaining a top coating material that forms a coating film excellent in adhesion, fingerprint resistance and coating film extensibility, carbonates are preferred, alkali metal carbonates and alkaline earth metal carbonates are more preferred, sodium carbonate, Sodium bicarbonate and calcium carbonate are more preferred, and calcium carbonate is even more preferred.

  The carbonate content in the inorganic filler is such that a coating film excellent in low-temperature film-forming stability is formed without using a large amount of a film-forming auxiliary, and even if it contains a large amount of inorganic filler, From the viewpoint of obtaining a top coating composition that forms a coating film excellent in whitening, adhesion, fingerprint resistance and coating film extensibility, preferably 80% by mass or more, more preferably 85% by mass or more, and further preferably 90% by mass. More preferably, it is 95% by mass or more, and its upper limit is 100% by mass.

  Examples of the shape of the inorganic filler include a spherical shape, a fibrous shape, a scale shape, a conical shape, a crushed shape, a planar shape, and an indefinite shape, but the present invention is not limited to such examples.

  The average particle diameter of the inorganic filler is such that a coating film excellent in low-temperature film-forming stability can be formed even if a large amount of inorganic filler is contained without using a large amount of film forming auxiliary, and hot water whitening resistance From the viewpoint of obtaining a top coating that forms a coating film excellent in adhesion, fingerprint resistance and coating film extensibility, preferably 0.3 μm or more, more preferably 0.5 μm or more, and further preferably 1 μm or more, Without using a large amount of film forming aid, it forms a coating film with excellent low-temperature film-forming stability even when a large amount of inorganic filler is contained, and also has resistance to warm water whitening, adhesion, fingerprint resistance and coating. From the viewpoint of obtaining a top coating composition that forms a coating film excellent in film extensibility, it is preferably 100 μm or less, more preferably 80 μm or less, and even more preferably 50 μm or less.

  In addition, the average particle diameter of an inorganic filler means the volume average particle diameter measured using the laser diffraction scattering method particle size distribution measuring apparatus [Beckman Coulter company make, product number: LS13320].

  The content of the inorganic filler in the total solid content of the emulsion particles and the inorganic filler is a coating that has excellent low-temperature film-forming stability even if a large amount of inorganic filler is contained without using a large amount of film forming aid. From the viewpoint of obtaining a top coating material that forms a film and forms a coating film excellent in hot water whitening resistance, adhesion, fingerprint resistance, and coating film extensibility, it is 50% by mass or more, and a large amount of film forming aid is used. In addition to forming a coating film with excellent low-temperature film-forming stability even when a large amount of inorganic filler is contained, it is excellent in warm water whitening resistance, adhesion, fingerprint resistance, and coating film stretchability. From the viewpoint of obtaining a top coating material for forming a coating film, it is 90% by mass or less, preferably 85% by mass or less, more preferably 80% by mass or less, still more preferably 75% by mass or less, and still more preferably 70% by mass or less. .

In the present specification, the content of the inorganic filler in the total solid content of the emulsion particles and the inorganic filler is expressed by the formula:
[Content of inorganic filler (% by mass) in the total solid content of emulsion particles and inorganic filler]
= [(Inorganic filler) / (Solid content of resin emulsion + Inorganic filler)] × 100
Means the value obtained based on

  In addition, the solid content of emulsion particles in the total solid content of emulsion particles and inorganic filler is low-temperature film-forming stability even if a large amount of inorganic filler is contained without using a large amount of film forming aid. From the viewpoint of obtaining a top coating material that forms a coating film excellent in hot water whitening resistance, adhesion, fingerprint resistance, and coating film stretchability, and at least 10% by mass, preferably 15% by mass % Or more, more preferably 20% by mass or more, and without using a large amount of film forming auxiliary, and forming a coating film excellent in low-temperature film-forming stability even if a large amount of inorganic filler is contained, From the viewpoint of obtaining a top coating material that forms a coating film excellent in hot water whitening resistance, adhesion, fingerprint resistance and coating film extensibility, it is 50% by mass or less.

  The aqueous resin composition for top coating of the present invention can be easily prepared, for example, by mixing a resin emulsion containing the emulsion particles, the inorganic filler, and a crosslinking agent as required. The order of mixing these components is arbitrary, and for example, these components may be mixed together.

  Examples of the crosslinking agent include melamine crosslinking agent, oxazoline crosslinking agent, acrylamide crosslinking agent, polyamide crosslinking agent, epoxy crosslinking agent, isocyanate crosslinking agent, aziridine crosslinking agent, titanate crosslinking agent, urea crosslinking. Agents, alkyl alcoholated urea-based crosslinking agents, hydrazine compounds, carbodiimide compounds, zirconium compounds, zinc compounds, titanium compounds, aluminum compounds, and the like, but the present invention is limited to such examples only. It is not a thing. These crosslinking agents may be used alone or in combination of two or more. The amount of the crosslinking agent is preferably set as appropriate according to the type of the crosslinking agent.

  Among these cross-linking agents, without using a large amount of film forming auxiliary, even if a large amount of inorganic filler is contained, a coating film excellent in low-temperature film-forming stability is formed, and hot water whitening resistance, From the viewpoint of obtaining a top coating material that forms a coating film excellent in adhesion, fingerprint resistance and coating film extensibility, an oxazoline-based crosslinking agent and a hydrazine compound are preferable.

  Examples of the oxazoline-based crosslinking agent include 2,2′-bis (2-oxazoline), 1,2-bis (2-oxazolin-2-yl) ethane, and 1,4-bis (2-oxazolin-2-yl). ) Butane, 1,8-bis (2-oxazolin-2-yl) butane, 1,4-bis (2-oxazolin-2-yl) cyclohexane, 1,2-bis (2-oxazolin-2-yl) benzene 1,3-bis (2-oxazolin-2-yl) benzene, 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2 -Isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline and the like. It is not limited only to hunt illustration. These oxazoline-based crosslinking agents may be used alone or in combination of two or more. The oxazoline-based crosslinking agent can be easily obtained commercially, for example, manufactured by Nippon Shokubai Co., Ltd., trade names: Epocross WS-500, Epocross WS-700, Epocross K-2010, Epocross K- 2020, Epochros K-2030, and the like, but the present invention is not limited to such examples.

  Examples of the hydrazine compound include adipic acid dihydrazide and a polymer having a dihydrazide group, but the present invention is not limited to such examples. These compounds may be used alone or in combination of two or more.

  The aqueous resin composition for top coating of the present invention forms a coating film excellent in low-temperature film-forming stability even when a large amount of an inorganic filler is contained without using a large amount of a film-forming auxiliary. Because it forms a coating film with excellent hot water whitening, adhesion, fingerprint resistance, and film stretchability, for example, a top coating called a top coat that is applied to the surface of interior materials of buildings, etc. Can be suitably used.

  The top coating composition of the present invention contains the above-described aqueous resin composition for top coating composition, may contain only the aqueous resin composition for top coating composition, and may further contain additives. Good.

  Examples of additives include colorants such as pigments, leveling agents, UV absorbers, UV stabilizers, antioxidants, polymerization inhibitors, fillers, coupling agents, rust inhibitors, antibacterial agents, and metal deactivators. Agent, wetting agent, antifoaming agent, surfactant, reinforcing agent, plasticizer, lubricant, anti-fogging agent, anticorrosive agent, pigment dispersant, flow control agent, peroxide decomposing agent, mold decoloring agent, fluorescent enhancement White agent, organic flame retardant, inorganic flame retardant, anti-dripping agent, melt flow modifier, antistatic agent, anti-algae agent, anti-mold agent, flame retardant, slip agent, metal chelating agent, anti-blocking agent, Examples include heat stabilizers, processing stabilizers, dispersants, thickeners, rheology control agents, foaming agents, anti-aging agents, preservatives, antistatic agents, silane coupling agents, antioxidants, and film forming aids. However, the present invention is not limited to such examples. These additives may be used alone or in combination of two or more.

  Since the amount of the additive varies depending on the type of the additive and cannot be generally determined, it is preferable to appropriately determine the amount depending on the type of the additive.

  The content of the film-forming auxiliary in the top coating composition of the present invention is such that a coating film excellent in low-temperature film-forming stability can be obtained without using a large amount of film-forming auxiliary and containing a large amount of inorganic filler. From the viewpoint of obtaining a top coat that forms a coating film excellent in hot water whitening resistance, adhesion, fingerprint resistance and coating film stretchability, preferably 5% by mass or less, more preferably 3% by mass or less, More preferably, it is 1 mass% or less.

  The non-volatile content in the top coating composition of the present invention forms a coating film excellent in low-temperature film-forming stability even when a large amount of an inorganic filler is contained without using a large amount of a film-forming auxiliary. From the viewpoint of obtaining a top coating material that forms a coating film excellent in warm water whitening resistance, adhesion, fingerprint resistance and coating film extensibility, it is preferably 30% by mass or more, more preferably 40% by mass or more, and handleability. From the viewpoint of improving the ratio, it is preferably 80% by mass or less, more preferably 70% by mass or less.

  The top coating composition of the present invention can be easily produced, for example, by mixing the water-based resin composition for top coating composition and, if necessary, additives, water and the like.

  Since the top coating composition of the present invention obtained as described above contains the aqueous resin composition for top coating composition, a large amount of inorganic filler can be contained without using a large amount of film forming aid. In addition to forming a coating film excellent in low-temperature film-forming stability, and forming a coating film excellent in hot water whitening resistance, adhesion, fingerprint resistance, and coating film extensibility, It can be suitably used as a top coating when the surface is painted.

  Examples of the interior material include a ceramic base material and a metal base material. Ceramic base materials are used for applications such as tiles and outer wall materials, for example. Ceramic base materials are the addition of inorganic fillers, fibrous materials, etc. to the hydraulic glue used as the raw material for inorganic hardened bodies, molding the resulting mixture, curing the resulting molded body, and curing it. Obtained by. Examples of inorganic building materials include flexible boards, calcium silicate boards, gypsum slag perlite boards, wood chip cement boards, precast concrete boards, ALC boards, and gypsum boards.

  The top coating composition of the present invention may be applied by only one layer, or may be applied by recoating so that two or more coating films are formed. When overcoating so that two or more coating films are formed, only a part of the coating film may be formed by the top coating material, or all coating films may be formed by the top coating material. .

  Examples of the method for forming a coating film using the top coating composition of the present invention include dip coating, brush coating, roll brush coating, spray coating, roll coating, spin coating, dip coating, bar coating, flow coating, and electrostatic coating. The figure which shows the coating method etc. by die-coat etc., this invention is not limited only to this illustration.

  The coating film formed using the top coating composition of the present invention may be dried at room temperature, for example, or may be dried by heating.

  In addition, the thickness of the coating film formed using the top coating composition of the present invention is excellent in low-temperature film-forming stability even when a large amount of inorganic filler is contained without using a large amount of film forming aid. From the viewpoint of obtaining a top coat that forms a coating film and forms a coating film excellent in hot water whitening resistance, adhesion, fingerprint resistance and coating film extensibility, it is usually preferably about 50 to 500 μm.

The amount of top coating applied to the base material varies depending on the type of the base material and cannot be determined unconditionally. However, a large amount of inorganic filler can be added without using a large amount of film forming aid. From the viewpoint of forming a coating film excellent in low-temperature film-forming stability and a top coating composition that forms a coating film excellent in hot water whitening resistance, adhesion, fingerprint resistance and coating film extensibility. The amount is preferably about 50 to 500 g / m ² .

  By applying the top coat to the substrate as described above, an interior material to which the top coat is applied can be obtained.

  EXAMPLES Next, although this invention is demonstrated further in detail based on an Example, this invention is not limited only to this Example. In the following production examples, examples and experimental examples, “part” means “part by mass” unless otherwise specified.

Preparation Example 404.9 parts of deionized water, 20 parts of a dispersant [manufactured by Kao Corporation, trade name: Demol EP], a dispersant [manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name: DISCOAT N-14] 16 .7 parts, defoaming agent [manufactured by San Nopco, trade name: Nopco 8034L], calcium carbonate [heavy calcium carbonate, manufactured by Maruo Calcium Co., Ltd., R heavy coal, average particle size: 7. 4 μm] 1000 parts and a thickener [made by Nippon Shokubai Co., Ltd., trade name: Acryset WR-503A] 6 parts are mixed with stirring with a disper and aged for 30 minutes, 100 mesh (JIS mesh, the same applies hereinafter) The paste with a non-volatile content of 70% by mass was obtained by filtering through a wire mesh.

Production Example 1
542 parts of deionized water was charged into a flask equipped with a dropping funnel, a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser. In a dropping funnel, 189 parts of deionized water, 40 parts of a 25% aqueous solution of an emulsifier [manufactured by ADEKA, trade name: Adekaria soap SR-10], 300 parts of styrene, 190 parts of 2-ethylhexyl acrylate, 5 parts of acrylic acid And 5 parts by weight of γ-methacryloyloxypropyltrimethoxysilane were prepared. Among them, 73 parts of the preemulsion for dropping corresponding to 5% by mass of the total amount of all the monomer components was added into the flask, and gently added. The temperature was raised to 80 ° C. while nitrogen gas was blown into the flask, and 10 parts of a 5% ammonium persulfate aqueous solution was added to the flask to initiate the polymerization reaction. Thereafter, the remainder of the pre-emulsion for dropping and 25 parts of 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 120 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 80 ° C. for 60 minutes, followed by 189 parts of deionized water, 40 parts of a 25% aqueous solution of an emulsifier (manufactured by ADEKA, trade name: Adeka Soap SR-10), Pre-emulsion for second-stage dropping comprising 200 parts of styrene, 220 parts of 2-ethylhexyl acrylate, 50 parts of n-butyl acrylate, 5 parts of methacrylic acid, 20 parts of 2-hydroxyethyl methacrylate and 5 parts of γ-methacryloyloxypropyltrimethoxysilane Was prepared, and the pre-emulsion was uniformly dropped into the flask together with 25 parts of 5% aqueous ammonium persulfate solution over 120 minutes.

  After completion of the dropping, the contents of the flask were maintained at 80 ° C. for 60 minutes, and the pH was adjusted to 8 by adding 25% aqueous ammonia to complete the polymerization reaction. After cooling the obtained reaction liquid to room temperature, the resin emulsion was prepared by filtering with a 300 mesh metal-mesh. The content of nonvolatile components in this resin emulsion was 49% by mass.

  The glass transition temperature of the inner layer of the emulsion particles contained in the resin emulsion obtained above is 9.9 ° C., the glass transition temperature of the outer layer is −14.9 ° C., and the glass transition temperature of the whole emulsion particles is −3.1 ° C. there were.

Production Example 2
542 parts of deionized water was charged into a flask equipped with a dropping funnel, a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser. In a dropping funnel, 189 parts of deionized water, 40 parts of a 25% aqueous solution of an emulsifier [manufactured by ADEKA, trade name: Adekaria Soap SR-10], 400 parts of styrene, 90 parts of 2-ethylhexyl acrylate, 5 parts of acrylic acid and A pre-emulsion for dropping consisting of 5 parts of γ-methacryloyloxypropyltrimethoxysilane was prepared, of which 73 parts of pre-emulsion for dropping corresponding to 5% by mass of the total amount of all monomer components was added into the flask, and gently nitrogen was added. The temperature was raised to 80 ° C. while blowing gas, and 10 parts of a 5% ammonium persulfate aqueous solution was added to the flask to initiate the polymerization reaction. Thereafter, the remainder of the pre-emulsion for dropping and 25 parts of 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 120 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 80 ° C. for 60 minutes, followed by 189 parts of deionized water, 40 parts of a 25% aqueous solution of an emulsifier (manufactured by ADEKA, trade name: Adeka Soap SR-10), Pre-emulsion for second-stage dropping comprising 250 parts of styrene, 170 parts of 2-ethylhexyl acrylate, 50 parts of n-butyl acrylate, 5 parts of methacrylic acid, 20 parts of 2-hydroxyethyl methacrylate and 5 parts of γ-methacryloyloxypropyltrimethoxysilane Was prepared, and the pre-emulsion was added dropwise into the flask uniformly over 120 minutes together with 25 parts of a 5% ammonium persulfate aqueous solution.

  After completion of the dropping, the contents of the flask were maintained at 80 ° C. for 60 minutes, and the pH was adjusted to 8 by adding 25% aqueous ammonia to complete the polymerization reaction. After cooling the obtained reaction liquid to room temperature, the resin emulsion was obtained by filtering with a 300 mesh metal-mesh. The content of nonvolatile components in this resin emulsion was 49% by mass.

  The glass transition temperature of the inner layer of the emulsion particles contained in the resin emulsion obtained above was 51.1 ° C., the glass transition temperature of the outer layer was 1 ° C., and the glass transition temperature of the entire emulsion particles was 23.9 ° C.

Production Example 3
542 parts of deionized water was charged into a flask equipped with a dropping funnel, a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser. In a dropping funnel, 189 parts of deionized water, 40 parts of a 25% aqueous solution of an emulsifier [manufactured by ADEKA, trade name: Adekaria Soap SR-10], 150 parts of styrene, 340 parts of 2-ethylhexyl acrylate, 5 parts of acrylic acid, A pre-emulsion for dropping consisting of 5 parts of γ-methacryloyloxypropyltrimethoxysilane was prepared, of which 73 parts of pre-emulsion for dropping corresponding to 5% by mass of the total amount of all monomer components was added into the flask, and gently nitrogen was added. The temperature was raised to 80 ° C. while blowing gas, and 10 parts of a 5% ammonium persulfate aqueous solution was added to the flask to initiate the polymerization reaction. Thereafter, the remainder of the pre-emulsion for dropping and 25 parts of 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 120 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 80 ° C. for 60 minutes, followed by 189 parts of deionized water, 40 parts of a 25% aqueous solution of an emulsifier (manufactured by ADEKA, trade name: Adeka Soap SR-10), Pre-emulsion for second-stage dropping comprising 200 parts of styrene, 220 parts of 2-ethylhexyl acrylate, 50 parts of n-butyl acrylate, 5 parts of methacrylic acid, 20 parts of 2-hydroxyethyl methacrylate and 5 parts of γ-methacryloyloxypropyltrimethoxysilane Was prepared and dropped into the flask uniformly over 120 minutes together with 25 parts of 5% aqueous ammonium persulfate solution.

  After completion of the dropping, the contents of the flask were maintained at 80 ° C. for 60 minutes, and the pH was adjusted to 8 by adding 25% aqueous ammonia to complete the polymerization reaction. After cooling the obtained reaction liquid to room temperature, the resin emulsion was obtained by filtering with a 300 mesh metal-mesh. The content of nonvolatile components in this resin emulsion was 49% by mass.

  The glass transition temperature of the inner layer of the emulsion particles contained in the resin emulsion obtained above is −35.4 ° C., the glass transition temperature of the outer layer is −14.9 ° C., and the glass transition temperature of the entire emulsion particles is −25.6 ° C. Met.

Production Example 4
542 parts of deionized water was charged into a flask equipped with a dropping funnel, a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser. From a dropping funnel, 113 parts of deionized water, 24 parts of a 25% aqueous solution of an emulsifier [manufactured by ADEKA, trade name: Adekaria soap SR-10], 190 parts of styrene, 107 parts of 2-ethylhexyl acrylate and 3 parts of acrylic acid A pre-emulsion for dripping is prepared, and 73 parts of the pre-emulsion for dripping corresponding to 5% by mass of the total amount of all monomer components is added to the flask, and the temperature is raised to 80 ° C. while gently blowing nitrogen gas, 10 parts of 5% aqueous ammonium persulfate solution was added into the flask to initiate the polymerization reaction. Thereafter, the remainder of the pre-emulsion for dropping and 15 parts of 5% aqueous ammonium persulfate solution were uniformly dropped into the flask over 60 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 80 ° C. for 60 minutes. Subsequently, 113 parts of deionized water, 24 parts of a 25% aqueous solution of an emulsifier (manufactured by ADEKA, trade name: Adeka Soap SR-10), A pre-emulsion for second-stage dropping comprising 100 parts of styrene, 192 parts of 2-ethylhexyl acrylate, 3 parts of acrylic acid and 5 parts of γ-methacryloyloxypropyltrimethoxysilane was prepared, and the pre-emulsion was added to a 5% aqueous ammonium persulfate solution 15 parts were added dropwise to the flask uniformly over 60 minutes.

  After completion of dropping, the contents of the flask were maintained at 80 ° C. for 60 minutes. Subsequently, 152 parts of deionized water, 32 parts of a 25% aqueous solution of an emulsifier [manufactured by ADEKA, trade name: Adeka Soap SR-10], Three stages comprising 190 parts of styrene, 30 parts of methyl methacrylate, 101 parts of 2-ethylhexyl acrylate, 50 parts of n-butyl acrylate, 4 parts of methacrylic acid, 20 parts of 2-hydroxyethyl methacrylate and 5 parts of γ-methacryloyloxypropyltrimethoxysilane A pre-emulsion for eye drop was prepared, and the pre-emulsion was dripped uniformly into the flask over 20 minutes together with 20 parts of 5% aqueous ammonium persulfate solution.

  After completion of the dropping, the contents of the flask were maintained at 80 ° C. for 60 minutes, and the pH was adjusted to 8 by adding 25% aqueous ammonia to complete the polymerization reaction. After cooling the obtained reaction liquid to room temperature, the resin emulsion was obtained by filtering with a 300 mesh metal-mesh. The content of nonvolatile components in this resin emulsion was 49% by mass.

  The emulsion particles contained in the resin emulsion obtained above have an inner layer glass transition temperature of 14.2 ° C., an intermediate layer glass transition temperature of −30.2 ° C., an outer layer glass transition temperature of 12.5 ° C., and emulsion particles. The overall glass transition temperature was -1.4 ° C.

Comparative production example 1
542 parts of deionized water was charged into a flask equipped with a dropping funnel, a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser. In a dropping funnel, 189 parts of deionized water, 40 parts of a 25% aqueous solution of an emulsifier [manufactured by ADEKA, trade name: Adekaria soap SR-10], 150 parts of styrene, 150 parts of methyl methacrylate, 190 parts of 2-ethylhexyl acrylate, A pre-emulsion for dropping consisting of 5 parts of acrylic acid and 5 parts of γ-methacryloyloxypropyltrimethoxysilane was prepared, and 73 parts of the pre-emulsion for dropping corresponding to 5% by mass of the total amount of all monomer components was added to the flask. Then, the temperature was raised to 80 ° C. while gently blowing nitrogen gas, and 10 parts of 5% ammonium persulfate aqueous solution was added to the flask to initiate the polymerization reaction. Thereafter, the remainder of the pre-emulsion for dropping and 25 parts of 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 120 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 80 ° C. for 60 minutes, followed by 189 parts of deionized water, 40 parts of a 25% aqueous solution of an emulsifier (manufactured by ADEKA, trade name: Adeka Soap SR-10), Two-stage consisting of 100 parts of styrene, 100 parts of methyl methacrylate, 220 parts of 2-ethylhexyl acrylate, 50 parts of n-butyl acrylate, 5 parts of methacrylic acid, 20 parts of 2-hydroxyethyl methacrylate and 5 parts of γ-methacryloyloxypropyltrimethoxysilane A pre-emulsion for eye drop was prepared, and the pre-emulsion was dripped uniformly into the flask over a period of 120 minutes together with 25 parts of a 5% ammonium persulfate aqueous solution.

  After completion of the dropping, the contents of the flask were maintained at 80 ° C. for 60 minutes, and the pH was adjusted to 8 by adding 25% aqueous ammonia to complete the polymerization reaction. After cooling the obtained reaction liquid to room temperature, the resin emulsion was obtained by filtering with a 300 mesh metal-mesh. The content of nonvolatile components in this resin emulsion was 49% by mass.

  The glass transition temperature of the inner layer of the emulsion particles contained in the resin emulsion obtained above is 10.8 ° C, the glass transition temperature of the outer layer is -14.4 ° C, and the glass transition temperature of the whole emulsion particles is -2.4 ° C. there were.

Comparative production example 2
542 parts of deionized water was charged into a flask equipped with a dropping funnel, a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser. In a dropping funnel, 189 parts of deionized water, 40 parts of a 25% aqueous solution of an emulsifier [manufactured by ADEKA, trade name: Adekaria Soap SR-10], 400 parts of styrene, 90 parts of 2-ethylhexyl acrylate, 5 parts of acrylic acid and A pre-emulsion for dropping consisting of 5 parts of γ-methacryloyloxypropyltrimethoxysilane was prepared, of which 73 parts of pre-emulsion for dropping corresponding to 5% by mass of the total amount of all monomer components was added into the flask, and gently nitrogen was added. The temperature was raised to 80 ° C. while blowing gas, and 10 parts of a 5% ammonium persulfate aqueous solution was added to the flask to initiate the polymerization reaction. Thereafter, the remainder of the pre-emulsion for dropping and 25 parts of 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 120 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 80 ° C. for 60 minutes, followed by 189 parts of deionized water, 40 parts of a 25% aqueous solution of an emulsifier (manufactured by ADEKA, trade name: Adeka Soap SR-10), Pre-emulsion for third-stage dropping comprising 400 parts of styrene, 20 parts of 2-ethylhexyl acrylate, 50 parts of n-butyl acrylate, 5 parts of methacrylic acid, 20 parts of 2-hydroxyethyl methacrylate and 5 parts of γ-methacryloyloxypropyltrimethoxysilane Was prepared, and the pre-emulsion was added dropwise into the flask uniformly over 120 minutes together with 25 parts of a 5% ammonium persulfate aqueous solution.

  After completion of the dropping, the contents of the flask were maintained at 80 ° C. for 60 minutes, and the pH was adjusted to 8 by adding 25% aqueous ammonia to complete the polymerization reaction. After cooling the obtained reaction liquid to room temperature, the resin emulsion was obtained by filtering with a 300 mesh metal-mesh. The content of nonvolatile components in this resin emulsion was 49% by mass.

  The glass transition temperature of the inner layer of the emulsion particles contained in the resin emulsion obtained above was 51.1 ° C., the glass transition temperature of the outer layer was 63 ° C., and the glass transition temperature of the entire emulsion particles was 56.9 ° C.

Example 1
While stirring 100 parts of the resin emulsion obtained in Production Example 1 at 1000 rpm with a homodisper, the solid content of the paste in the total solid content of the resin emulsion and the paste is 60% by mass. After adding the obtained paste to the resin emulsion, an appropriate amount of diluted water, black paste [manufactured by Yokohama Kasei Co., Ltd., trade name: Uniland 88, Conch Black] and silicone so that the nonvolatile content is 50% by mass 1.5 parts of an antifoaming agent (manufactured by San Nopco, trade name: SN deformer 777) was added. Then, a thickener [manufactured by Nippon Shokubai Co., Ltd., trade name: ACRISE WR- so that the viscosity at 25 ° C. at a rotation speed of 30 rpm is 2,000 mPa · s with a BM type viscometer [manufactured by Tokyo Keiki Co., Ltd.] 503A] was added, and the mixture was stirred for 30 minutes to obtain an aqueous resin composition for top coating.

Example 2
While stirring 100 parts of the resin emulsion obtained in Production Example 1 at 1000 rpm with a homodisper, the solid content of the paste in the total solid content of the resin emulsion and paste is 51% by mass. After adding the obtained paste to the resin emulsion, an appropriate amount of diluted water, black paste [manufactured by Yokohama Kasei Co., Ltd., trade name: Uniland 88, Conch Black] and silicone so that the nonvolatile content is 50% by mass 1.5 parts of an antifoaming agent (manufactured by San Nopco, trade name: SN deformer 777) was added. Then, a thickener [manufactured by Nippon Shokubai Co., Ltd., trade name: ACRISE WR- so that the viscosity at 25 ° C. at a rotation speed of 30 rpm is 2,000 mPa · s with a BM type viscometer [manufactured by Tokyo Keiki Co., Ltd.] 503A] was added, and the mixture was stirred for 30 minutes to obtain an aqueous resin composition for top coating.

Example 3
While stirring 100 parts of the resin emulsion obtained in Production Example 1 with a homodisper at 1000 rpm, the solid content of the paste in the total solid content of the resin emulsion and the paste is 80% by mass. After adding the obtained paste to the resin emulsion, an appropriate amount of diluted water, black paste [manufactured by Yokohama Kasei Co., Ltd., trade name: Uniland 88, Conch Black] and silicone so that the nonvolatile content is 50% by mass 1.5 parts of an antifoaming agent (manufactured by San Nopco, trade name: SN deformer 777) was added. Then, a thickener [manufactured by Nippon Shokubai Co., Ltd., trade name: ACRISE WR- so that the viscosity at 25 ° C. at a rotation speed of 30 rpm is 2,000 mPa · s with a BM type viscometer [manufactured by Tokyo Keiki Co., Ltd.] 503A] was added, and the mixture was stirred for 30 minutes to obtain an aqueous resin composition for top coating.

Example 4
While stirring 100 parts of the resin emulsion obtained in Production Example 1 at 1000 rpm with a homodisper, the solid content of the paste in the total solid content of the resin emulsion and the paste is 60% by mass. After adding the obtained paste to the resin emulsion, an appropriate amount of diluted water, black paste [manufactured by Yokohama Kasei Co., Ltd., trade name: Uniland 88, Conch Black] and silicone so that the nonvolatile content is 50% by mass 1.5 parts of an antifoaming agent (manufactured by San Nopco, trade name: SN deformer 777) was added. Then, a thickener [manufactured by Nippon Shokubai Co., Ltd., trade name: ACRISE WR- so that the viscosity at 25 ° C. at a rotation speed of 30 rpm is 2,000 mPa · s with a BM type viscometer [manufactured by Tokyo Keiki Co., Ltd.] 503A] was added, and the mixture was stirred in that state for 30 minutes to obtain a mixed solution.

  Next, while stirring 99.5 parts of the mixed solution obtained above at 1000 rpm with a homodisper, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate [manufactured by JNC Corporation, Product No .: CS-12] 0.5 part was added, and the mixture was stirred for 30 minutes to obtain an aqueous resin composition for top coating.

Example 5
While stirring 100 parts of the resin emulsion obtained in Production Example 1 at 1000 rpm with a homodisper, the solid content of the paste in the total solid content of the resin emulsion and the paste is 60% by mass. After adding the obtained paste to the resin emulsion, an appropriate amount of diluted water, black paste [manufactured by Yokohama Kasei Co., Ltd., trade name: Uniland 88, Conch Black] and silicone so that the nonvolatile content is 50% by mass 1.5 parts of an antifoaming agent (manufactured by San Nopco, trade name: SN deformer 777) was added. Then, a thickener [manufactured by Nippon Shokubai Co., Ltd., trade name: ACRISE WR- so that the viscosity at 25 ° C. at a rotation speed of 30 rpm is 2,000 mPa · s with a BM type viscometer [manufactured by Tokyo Keiki Co., Ltd.] 503A] was added, and the mixture was stirred in that state for 30 minutes to obtain a mixed solution.

  Next, while stirring 98 parts of the mixed solution obtained above with a homodisper at 1000 rpm, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate [manufactured by JNC Corporation, product number: CS-12] 2 parts was added, and the mixture was stirred for 30 minutes to obtain an aqueous resin composition for top coating.

Example 6
While stirring 100 parts of the resin emulsion obtained in Production Example 2 with a homodisper at 1000 rpm, the solid content of the paste in the total solid content of the resin emulsion and the paste is 60% by mass. After adding the obtained paste to the resin emulsion, an appropriate amount of diluted water, black paste [manufactured by Yokohama Kasei Co., Ltd., trade name: Uniland 88, Conch Black] and silicone so that the nonvolatile content is 50% by mass 1.5 parts of an antifoaming agent (manufactured by San Nopco, trade name: SN deformer 777) was added. Then, a thickener [manufactured by Nippon Shokubai Co., Ltd., trade name: ACRISE WR- so that the viscosity at 25 ° C. at a rotation speed of 30 rpm is 2,000 mPa · s with a BM type viscometer [manufactured by Tokyo Keiki Co., Ltd.] 503A] was added, and the mixture was stirred in that state for 30 minutes to obtain a mixed solution.

  Next, while stirring 95 parts of the mixed solution obtained above with a homodisper at 1000 rpm, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate [manufactured by JNC Corporation, product number: CS-12] 5 parts was added, and the mixture was stirred for 30 minutes to obtain an aqueous resin composition for top coating.

Example 7
While stirring 100 parts of the resin emulsion obtained in Production Example 3 with a homodisper at 1000 rpm, the solid content of the paste in the total solid content of the resin emulsion and the paste is 60% by mass. After adding the obtained paste to the resin emulsion, an appropriate amount of diluted water, black paste [manufactured by Yokohama Kasei Co., Ltd., trade name: Uniland 88, Conch Black] and silicone so that the nonvolatile content is 50% by mass 1.5 parts of an antifoaming agent (manufactured by San Nopco, trade name: SN deformer 777) was added. Then, a thickener [manufactured by Nippon Shokubai Co., Ltd., trade name: ACRISE WR- so that the viscosity at 25 ° C. at a rotation speed of 30 rpm is 2,000 mPa · s with a BM type viscometer [manufactured by Tokyo Keiki Co., Ltd.] 503A] was added, and the mixture was stirred for 30 minutes to obtain an aqueous resin composition for top coating.

Example 8
While stirring 100 parts of the resin emulsion obtained in Production Example 4 at 1000 rpm with a homodisper, the solid content of the paste in the total solid content of the resin emulsion and the paste is 60% by mass. After adding the obtained paste to the resin emulsion, an appropriate amount of diluted water, black paste [manufactured by Yokohama Kasei Co., Ltd., trade name: Uniland 88, Conch Black] and silicone so that the nonvolatile content is 50% by mass 1.5 parts of an antifoaming agent (manufactured by San Nopco, trade name: SN deformer 777) was added. Then, a thickener [manufactured by Nippon Shokubai Co., Ltd., trade name: ACRISE WR- so that the viscosity at 25 ° C. at a rotation speed of 30 rpm is 2,000 mPa · s with a BM type viscometer [manufactured by Tokyo Keiki Co., Ltd.] 503A] was added, and the mixture was stirred for 30 minutes to obtain an aqueous resin composition for top coating.

Comparative Example 1
While stirring 100 parts of the resin emulsion obtained in Production Example 1 at 1000 rpm with a homodisper, the solid content of the paste in the total solid content of the resin emulsion and the paste is 35% by mass. After adding the obtained paste to the resin emulsion, an appropriate amount of diluted water, black paste [manufactured by Yokohama Kasei Co., Ltd., trade name: Uniland 88, Conch Black] and silicone so that the nonvolatile content is 50% by mass 1.5 parts of an antifoaming agent (manufactured by San Nopco, trade name: SN deformer 777) was added. Then, a thickener [manufactured by Nippon Shokubai Co., Ltd., trade name: ACRISE WR- so that the viscosity at 25 ° C. at a rotation speed of 30 rpm is 2,000 mPa · s with a BM type viscometer [manufactured by Tokyo Keiki Co., Ltd.] 503A] was added, and the mixture was stirred for 30 minutes to obtain an aqueous resin composition for top coating.

Comparative Example 2
While stirring 100 parts of the resin emulsion obtained in Production Example 1 at 1000 rpm with a homodisper, the solid content of the paste in the total solid content of the resin emulsion and the paste is 95% by mass. After adding the obtained paste to the resin emulsion, an appropriate amount of diluted water, black paste [manufactured by Yokohama Kasei Co., Ltd., trade name: Uniland 88, Conch Black] and silicone so that the nonvolatile content is 50% by mass 1.5 parts of an antifoaming agent (manufactured by San Nopco, trade name: SN deformer 777) was added. Then, a thickener [manufactured by Nippon Shokubai Co., Ltd., trade name: ACRISE WR- so that the viscosity at 25 ° C. at a rotation speed of 30 rpm is 2,000 mPa · s with a BM type viscometer [manufactured by Tokyo Keiki Co., Ltd.] 503A] was added, and the mixture was stirred for 30 minutes to obtain an aqueous resin composition for top coating.

Comparative Example 3
While stirring 100 parts of the resin emulsion obtained in Comparative Production Example 1 at 1000 rpm with a homodisper, the solid content of the paste in the total solid content of the resin emulsion and paste is 60% by mass. After adding the obtained paste to the resin emulsion, 10 parts of an appropriate amount of dilution water, black paste [manufactured by Yokohama Kasei Co., Ltd., trade name: UNILANT 88, Conch Black] so that the nonvolatile content is 50% by mass, and 1.5 parts of a silicone-based antifoaming agent (manufactured by San Nopco, trade name: SN deformer 777) was added. Then, a thickener [manufactured by Nippon Shokubai Co., Ltd., trade name: ACRISE WR- so that the viscosity at 25 ° C. at a rotation speed of 30 rpm is 2,000 mPa · s with a BM type viscometer [manufactured by Tokyo Keiki Co., Ltd.] 503A] was added, and the mixture was stirred for 30 minutes to obtain an aqueous resin composition for top coating.

Comparative Example 4
While stirring 100 parts of the resin emulsion obtained in Comparative Production Example 2 with a homodisper at 1000 rpm, the solid content of the paste in the total solid content of the resin emulsion and the paste is 60% by mass in the preparation example. After adding the obtained paste to the resin emulsion, 10 parts of an appropriate amount of dilution water, black paste [manufactured by Yokohama Kasei Co., Ltd., trade name: UNILANT 88, Conch Black] so that the nonvolatile content is 50% by mass, and 1.5 parts of a silicone-based antifoaming agent (manufactured by San Nopco, trade name: SN deformer 777) was added. Then, a thickener [manufactured by Nippon Shokubai Co., Ltd., trade name: ACRISE WR- so that the viscosity at 25 ° C. at a rotation speed of 30 rpm is 2,000 mPa · s with a BM type viscometer [manufactured by Tokyo Keiki Co., Ltd.] 503A] was added, and the mixture was stirred in that state for 30 minutes to obtain a mixed solution.

  Next, while stirring 90 parts of the mixed solution obtained above at 1000 rpm with a homodisper, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate [manufactured by JNC Corporation, product number: CS-12] 10 parts was added, and the mixture was stirred for 30 minutes to obtain an aqueous resin composition for top coating.

  Based on the following methods, the properties of the aqueous resin composition for top coating obtained in each Example and each Comparative Example are resistance to warm water whitening, stability to low temperature film formation, adhesion, fingerprint resistance, and film stretchability. I investigated. The results are shown in Table 1.

[Hot water whitening resistance]
An aqueous resin composition for top coating is applied to a black acrylic resin plate (manufactured by Nippon Test Panel Co., Ltd., length: 70 mm, width: 150 mm, thickness: 3 mm) with a 10 mil applicator, and 1 in air at 23 ° C. A test plate was obtained by drying for a week.

  The L value (L value before the test) of the test plate obtained above was measured with a color difference meter [manufactured by Nippon Denshoku Industries Co., Ltd., spectroscopic color difference meter SE-2000].

Next, after immersing the test plate in warm water kept at a water temperature of 50 ° C. for 24 hours, the test plate was taken out from the hot water, thoroughly wiped off moisture, and the L value ( L value after test) is measured, and the color difference (ΔL) is expressed by the formula:
[Color difference (ΔL)] = [L value after test] − [L value before test]
The hot water whitening resistance was evaluated based on the following evaluation criteria.
(Evaluation criteria)
20 points: ΔL is less than 5 10 points: ΔL is 5 or more and less than 10 0 point: ΔL is 10 or more (failed)

[Low-temperature film-forming stability]
An evaluation coating was obtained by adding 10 parts by mass of water to 100 parts by mass of the aqueous resin composition for top coating.

Next, a slate plate (manufactured by Nippon Test Panel Co., Ltd., length: 70 mm, width: 150 mm, thickness: 6 mm) is sealed with a sealer (manufactured by SK Kaken Co., Ltd., trade name: EX sealer) by air spray. After coating uniformly with a coating amount of m ² and drying in the air at 23 ° C. for 1 week, the evaluation paint obtained above is applied with a 10 mil applicator onto the coating film formed on the surface of the slate plate. And it was made to dry for 24 hours in the thermostat adjusted to 5 degreeC, and the test plate was obtained.

The test plate obtained above was immersed in water kept at a water temperature of 23 ° C. for 24 hours, then removed from the water, sufficiently wiped off the moisture, and further dried in the atmosphere at 23 ° C. for 24 hours, and then expanded. The appearance of the coating film was observed with a magnifying glass having a magnification of 10 times, and the low-temperature film-forming stability was evaluated based on the following evaluation criteria.
(Evaluation criteria)
20 points: No cracks are observed in the coating film.
10 points: Cracks of less than 5 mm in length are observed in the coating film.
0 point: A crack having a length of 5 mm or more is observed in the coating film (failed).

[Adhesion]
A slate plate (manufactured by Nippon Test Panel Co., Ltd., length: 70 mm, width: 150 mm, thickness: 6 mm) and a sealer (manufactured by SK Kaken Co., Ltd., trade name: EX sealer) by air spray are 150 / m ^2. After uniformly drying in the air at 23 ° C. for 1 week, the aqueous resin composition for top coating is applied on the coating film formed on the surface of the slate plate using a 10 mil applicator. The test plate was obtained by drying in the atmosphere at 23 ° C. for 1 week.

The test plate obtained above was immersed in warm water maintained at a temperature of 50 ° C. for 24 hours, then removed from the warm water, sufficiently wiped off moisture, and further dried in the atmosphere at 23 ° C. for 24 hours. Thereafter, the coating film on the test plate was cut with a cutter knife so that 100 squares of 2 mm square were formed, and cellophane adhesive tape [trade name: Cellotape (registered trademark) CT405AP-18, manufactured by Nichiban Co., Ltd.] Was stuck on this grid, a peel test was performed in accordance with JIS K5400, the number of grids remaining was counted, and the adhesion was evaluated based on the following evaluation criteria.
(Evaluation criteria)
20 points: 90 or more remaining grids 10 points: 70 to 89 remaining grids 0 points: 69 or less remaining grids

[Fingerprint resistance]
A slate plate (manufactured by Nippon Test Panel Co., Ltd., length: 70 mm, width: 150 mm, thickness: 6 mm) and a sealer (manufactured by SK Kaken Co., Ltd., trade name: EX sealer) by air spray are 150 / m ^2. After uniformly drying in the air at 23 ° C. for 1 week, the aqueous resin composition for top coating is applied on the coating film formed on the surface of the slate plate using a 10 mil applicator. The test plate was obtained by drying in the atmosphere at 23 ° C. for 1 week.

After pressing the experimenter's thumb against the surface of the test plate obtained above for about 10 seconds, the appearance of the coating film was visually observed, and fingerprint resistance was evaluated based on the following evaluation criteria.
(Evaluation criteria)
20 points: No fingerprints are observed on the coating film.
10 points: A slight fingerprint is observed on the coating film.
0 point: A fingerprint is clearly observed on the coating film.

[Coating film extensibility]
Sealer [ESK Kaken Co., Ltd., trade name: EX sealer] is applied to a slate plate (manufactured by Nippon Test Panel Co., Ltd., length: 70 mm, width: 150 mm, thickness: 6 mm) by air spray at 150 g / m ² . After uniformly applying the coating amount and drying in the air at 23 ° C. for 1 week, an acrylic emulsion [manufactured by Nippon Shokubai Co., Ltd., trade name: Acryset EMN-325E (glass transition temperature: −55 ° C.) ] Was applied with a 20 mil applicator and dried in air at 23 ° C. for 1 week. Thereafter, the aqueous resin composition for top coating was applied on the coating film formed on the surface of the slate plate with a 20 mil applicator and dried in the atmosphere at 23 ° C. for one week, and then the appearance of the coating film was visually observed. Observed and evaluated the stretchability of the coating film based on the following evaluation criteria.
(Evaluation criteria)
20 points: No abnormality in the coating film.
10 points: 1-2 cracks are observed in the coating film.
0 point: Three or more cracks are observed in the coating film.

〔Comprehensive evaluation〕
Total evaluation (100 points maximum) was performed by summing up the evaluation scores in each test item. In addition, the water-based resin composition for top-coat paint which has even one 0 point | piece evaluation in physical property evaluation fails.

  From the results shown in Table 1, each of the waterborne resin compositions for topcoats obtained in each example may contain a large amount of an inorganic filler without using a large amount of a film forming auxiliary. It can be seen that a coating film excellent in low-temperature film-forming stability is formed and a coating film excellent in hot water whitening resistance, adhesion, fingerprint resistance and coating film stretchability is formed.

  The aqueous resin composition for top coating of the present invention forms a coating film excellent in low-temperature film-forming stability even when a large amount of an inorganic filler is contained without using a large amount of a film-forming auxiliary. Because it forms a coating film with excellent hot water whitening, adhesion, fingerprint resistance, and film stretchability, it can be applied, for example, to a top coat called a top coat that is applied to the surface of interior materials of buildings. It is expected to be used.

Claims (3)

  An aqueous resin composition used for a top coating, which contains emulsion particles and an inorganic filler, wherein the content of the inorganic filler in the total solid content of the emulsion particles and the inorganic filler is 50 to 90% by mass, and the emulsion An aqueous resin composition for top coating, wherein the monomer component used as a raw material for the particles contains 30 to 70% by mass of a styrene monomer.   A method for producing an aqueous resin composition for use in a top coating, wherein a monomer component containing 30 to 70% by mass of a styrene monomer is emulsion-polymerized, and a resin emulsion containing emulsion particles obtained and When mixing an inorganic filler, the content of the inorganic filler in the total solid content of the emulsion particles and the inorganic filler is adjusted to 50 to 90% by mass, and the method for producing an aqueous resin composition for top coating .   A top coating composition comprising the aqueous resin composition for top coating composition according to claim 1.