JP6664918B2 - Method for producing aqueous resin dispersion - Google Patents

Description

  The present invention relates to a method for producing an aqueous resin dispersion. More specifically, the present invention relates to a method for producing an aqueous resin dispersion useful for applications such as paints and coating agents.

  In recent years, an aqueous paint containing an aqueous resin dispersion has been used from the viewpoint of avoiding deterioration of the environment due to emission of volatile organic compounds into the atmosphere. However, since water-based paint uses water as a solvent, the weather resistance of a formed coating film is generally inferior to that of an organic solvent-based paint. A method for producing an aqueous resin dispersion that forms a coating film having excellent weather resistance and a property of preventing the coating film from flowing down even when the coating film is formed in a vertical direction (hereinafter referred to as pattern retention). As the aqueous resin dispersion, the content of the acid group-containing monomer in the monomer component used as a raw material of the polymer constituting the emulsion particles contained in the aqueous resin dispersion is adjusted to 0.3% by mass or less. A manufacturing method has been proposed (for example, see Patent Document 1).

  According to the method for producing an aqueous resin dispersion, a coating film excellent in weather resistance and pattern retention can be formed. However, recently, there has been a demand for the development of an aqueous resin dispersion which forms a thick coating film having excellent pattern retention, weather resistance and discoloration resistance.

JP 2014-031456 A

  The present invention has been made in view of the related art, and has an object to provide a method for producing an aqueous resin dispersion which forms a thick coating film having excellent pattern retention, weather resistance, and discoloration resistance. And

The present invention
(1) Aqueous resin dispersion containing emulsion particles by subjecting monomer component (I) and monomer component (II) containing an acid group-containing monomer having an ethylenically unsaturated double bond to multistage emulsion polymerization. A method for producing a monomer component, comprising adjusting the amount of the monomer component (I) to be 35 to 80% by mass of all monomer components used in the multi-stage emulsion polymerization. ) At pH 1 to 5 when emulsion polymerization is carried out, as the monomer component (I), a monomer component (Ia) composed of an alkyl (meth) acrylate and an acid group having an ethylenically unsaturated double bond. Using a monomer component (Ib) containing an ethylenically unsaturated double bond-containing monomer containing a monomer, and after emulsion-polymerizing the monomer component (Ia), the monomer component ( Ib) is emulsion-polymerized, the pH of the resin emulsion (I) obtained by the emulsion polymerization is adjusted to 6 to 10, and then the hydroxyl-containing (e.g., The monomer component (II) containing an ethylenically unsaturated double bond-containing monomer containing an acrylate and a (meth) acryloyl group-containing piperidine compound is prepared by mixing 20 to 65 of the total monomer components used in the multistage emulsion polymerization. Aqueous resin dispersion, which is added to the resin emulsion (I) in an amount of% by mass and emulsion-polymerized, and the pH of the resin emulsion (II) obtained by the emulsion polymerization is increased by 0.5 to 2 Manufacturing method,
(2) The above-mentioned (1), wherein the ethylenically unsaturated double bond-containing monomer used in the monomer component (II) contains a hydroxyl group-containing (meth) acrylate and a (meth) acryloyl group-containing piperidine compound. A method for producing an aqueous resin dispersion,
(3) A method for producing an aqueous resin dispersion containing emulsion particles by subjecting the monomer component (I) and the monomer component (II) to multi-stage emulsion polymerization, wherein the monomer component (I) is ethylene. A monomer component comprising an acid group-containing monomer having an unsaturated double bond , methyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, wherein the monomer component (II) is methyl (meth) acrylate , 2-ethylhexyl (meth) acrylate and a (meth) acryloyl group-containing piperidine compound, wherein the amount of the monomer component (I) is 35% of the total monomer components used in the multistage emulsion polymerization. To 80% by mass, the monomer component (I) was emulsion-polymerized in a state of pH 1 to 5, and the pH of the resin emulsion (I) obtained by the emulsion polymerization was adjusted to 6 to 10. Later, used for multi-stage emulsion polymerization The monomer component (II) is added to the resin emulsion (I) in an amount of 20 to 65% by mass of the total monomer components to be emulsion-polymerized, and the monomer component (II) is obtained by the emulsion polymerization. A method for producing an aqueous resin dispersion, wherein the pH of the resin emulsion (II) is increased by 0.5 to 2;
(4) Aqueous resin containing emulsion particles obtained by subjecting monomer component (I) containing an acid group-containing monomer having an ethylenically unsaturated double bond and monomer component (II) to multistage emulsion polymerization. A method for producing a dispersion, wherein the monomer component (I) contains an acid group-containing monomer having an ethylenically unsaturated double bond, an alkyl (meth) acrylate and a styrene-based monomer. Monomer component (II) is a monomer component containing an alkyl (meth) acrylate and a silane group-containing monomer having an ethylenically unsaturated double bond ; ) Is adjusted to be 35 to 80% by mass of all the monomer components used in the multistage emulsion polymerization, and the monomer component (I) is emulsion-polymerized at a pH of 1 to 5 to obtain the emulsion polymerization. After adjusting the pH of the resin emulsion (I) obtained by the above to 6 to 10, the multi-stage emulsification The monomer component (II) is added to the resin emulsion (I) in an amount of 20 to 65% by mass of the total monomer components used for the emulsion polymerization, and the monomer component (II) is emulsion-polymerized. A process for producing an aqueous resin dispersion, wherein the pH of the resin emulsion (II) obtained by the above method is increased by 0.5 to 2, and (5) the monomer component (I) is ethylenically unsaturated. A monomer component containing an acid group-containing monomer having a double bond , cyclohexyl (meth) acrylate, methyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and a styrene monomer; The aqueous solution according to the above (4), wherein the body component (II) is a monomer component containing cyclohexyl (meth) acrylate, butyl (meth) acrylate and a silane group-containing monomer having an ethylenically unsaturated double bond. Resin dispersion Production method on.

  According to the method for producing an aqueous resin dispersion of the present invention, it is possible to obtain an aqueous resin dispersion which forms a thick coating film having excellent pattern retention, weather resistance and discoloration resistance.

  The method for producing an aqueous resin dispersion of the present invention is, as described above, a method for producing an aqueous resin dispersion containing emulsion particles, and includes a monomer containing an acid group-containing monomer as a monomer component. Using the component (I) and the monomer component (II), the amount of the monomer component (I) is adjusted so as to be 35 to 80% by mass of all the monomer components used in the multistage emulsion polymerization. After the emulsion polymerization of the monomer component (I) at a pH of 1 to 5, the pH of the resin emulsion (I) obtained by the emulsion polymerization is adjusted to 6 to 10, and then the total amount used in the multistage emulsion polymerization is adjusted. A monomer component (II) in an amount of 20 to 65% by mass of the monomer component is added to the resin emulsion (I), the monomer component (II) is emulsion-polymerized, and the resin obtained by the emulsion polymerization is added. It is characterized in that the pH of the emulsion (II) is increased by 0.5 to 2.

  In the method for producing an aqueous resin dispersion of the present invention, since the above operation is employed, an aqueous resin dispersion that forms a coating film having excellent pattern retention, weather resistance and discoloration resistance as a thick film is obtained. Can be.

  In the present invention, the monomer component (I) containing an acid group-containing monomer is used in the emulsion polymerization of the monomer component (I).

  Examples of the acid group-containing monomer include acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, maleic anhydride, maleic acid monomethyl ester, maleic acid monobutyl ester, and monomethyl itaconate Examples thereof include carboxyl group-containing aliphatic monomers such as esters, monobutyl itaconate, and vinylbenzoic acid, but the present invention is not limited to these examples. These acid group-containing monomers may be used alone or in combination of two or more. Among these acid group-containing monomers, acrylic acid, methacrylic acid and itaconic acid are preferable from the viewpoint of forming a coating film having excellent pattern retention, weather resistance and discoloration resistance as a thick film, and acrylic acid and Methacrylic acid is more preferred.

  The content of the acid group-containing monomer in the monomer component (I) is preferably 0.3% by mass or more, more preferably 0.1% by mass, from the viewpoint of forming a coating film having excellent discoloration resistance as a thick film. 5% by mass or more, more preferably 1% by mass or more, and preferably 10% by mass or less, more preferably 8% by mass or less, still more preferably 6% by mass, from the viewpoint of forming a coating film having excellent pattern retention. The content is even more preferably 5% by mass or less. Further, the content of the monomer other than the acid group-containing monomer in the monomer component (I) is preferably 90% by mass or more, more preferably from the viewpoint of forming a coating film having excellent pattern retention. 92% by mass or more, more preferably 94% by mass or more, still more preferably 95% by mass or more, and preferably 99.7% by mass or less, from the viewpoint of forming a coating film excellent in discoloration resistance as a thick film, The content is more preferably 99.5% by mass or less, and further preferably 99% by mass or less.

  Monomers other than the acid group-containing monomer include monofunctional monomers and polyfunctional monomers. The monofunctional monomer and the polyfunctional monomer may be used alone or in combination.

  The monofunctional monomer includes, for example, an ethylenically unsaturated double bond-containing monomer, but the present invention is not limited to such examples.

  Examples of the ethylenically unsaturated double bond-containing monomer include an alkyl (meth) acrylate, a hydroxyl group-containing (meth) acrylate, a piperidyl group-containing monomer, an oxo group-containing monomer, a fluorine atom-containing monomer, Nitrogen atom-containing monomer, epoxy group-containing monomer, alkoxyalkyl (meth) acrylate, silane group-containing monomer, carbonyl group-containing monomer, aziridinyl group-containing monomer, styrene-based monomer, aralkyl ( Although (meth) acrylate etc. are mentioned, this invention is not limited only to such an illustration. These ethylenically unsaturated double bond-containing monomers may be used alone or in combination of two or more.

  In the present invention, “(meth) acrylate” means “acrylate” or “methacrylate”, and “(meth) acryl” means “acryl” or “methacryl”.

  Examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, sec-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, tridecyl (meth) acrylate, cyclohexyl (meth) acrylate, n-lauryl (meth) Acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, alkyl (meth) acrylate having 1 to 18 carbon atoms of an ester group such as isobornyl methacrylate, and the like, It is not limited only to hunt illustration. These monomers may be used alone or in combination of two or more. In the present invention, the alkyl (meth) acrylate is a concept including (meth) acrylate having an alicyclic structure.

  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 thereof include a hydroxyl group-containing (meth) acrylate having 1 to 18 carbon atoms in an ester group such as butyl (meth) acrylate, but the present invention is not limited to only such examples. These hydroxyl group-containing (meth) acrylates may be used alone or in combination of two or more.

  Examples of the piperidyl group-containing monomer include 4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine and 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- Ano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4-cyano -4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine and the like, but the present invention is not limited thereto. Is not limited only to such an example. These monomers may be used alone or in combination of two or more.

  Examples of the oxo group-containing monomer include (di) ethylene glycol (methoxy) (meth) acrylates 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 only 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 a 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. Examples include (meth) acrylate, but the present invention is not limited to only such examples. These fluorine atom-containing monomers may be used alone or in combination of two or more.

  Examples of the nitrogen atom-containing monomer include (meth) acrylamide, N-monomethyl (meth) acrylamide, N-monoethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, and Nn-propyl (meth) Acrylamide, N-isopropyl (meth) acrylamide, methylenebis (meth) acrylamide, N-methylol (meth) acrylamide, N-butoxymethyl (meth) acrylamide, dimethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropylacrylamide, Acrylamide compounds such as diacetone acrylamide; nitrogen atom-containing (meth) acrylate compounds such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; N-vinylpyrrolidone; Data) but and 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.

  Epoxy group-containing monomers include, for example, epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate, α-methylglycidyl (meth) acrylate, and glycidyl allyl ether. It is not limited to only. These epoxy group-containing monomers may be used alone or in combination of two or more.

  Examples of the alkoxyalkyl (meth) acrylate include methoxyethyl (meth) acrylate, methoxybutyl (meth) acrylate, ethoxybutyl (meth) acrylate, and trimethylolpropane tripropoxy (meth) acrylate. However, the present invention is not limited to only such an example. These alkoxyalkyl (meth) acrylates may be used alone or in combination of two or more.

  Examples of the silane group-containing monomer include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (methoxyethoxy) silane, γ- (meth) acryloyloxypropyltrimethoxysilane, 2-styrylethyltrimethoxysilane, and vinyltrimethoxysilane. Examples thereof 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.

  Examples of the carbonyl group-containing monomer include acrolein, boromil styrene, vinyl ethyl ketone, (meth) acryloxyalkylpropenal, acetonyl (meth) acrylate, diacetone (meth) acrylate, 2-hydroxypropyl (meth) acrylate Examples include acetyl acetate, butanediol-1,4-acrylate acetyl acetate, 2- (acetoacetoxy) ethyl (meth) acrylate, and the like, but the present invention is not limited only to such examples. These carbonyl group-containing monomers may be used alone or in combination of two or more.

  Examples of the aziridinyl group-containing monomer include (meth) acryloylaziridine, 2-aziridinylethyl (meth) acrylate, and the like, but the present invention is not limited to only such examples. These aziridinyl group-containing monomers may be used alone or in combination of two or more.

  Examples of the styrene-based monomer include, for example, styrene, α-methylstyrene, p-methylstyrene, tert-methylstyrene, chlorostyrene, vinyltoluene, and the like, but the present invention is limited to only such examples. is not. These monomers may be used alone or in combination of two or more. Styrene-based monomers have a benzene ring having a functional group such as an alkyl group such as a methyl group or a tert-butyl group, a nitro group, a nitrile group, an alkoxyl group, an acyl group, a sulfone group, a hydroxyl group, or a halogen atom. You may. Among the styrene monomers, styrene is preferred from the viewpoint of improving the weather resistance of the coating film.

  Examples of the aralkyl (meth) acrylate include aralkyl having an aralkyl group having 7 to 18 carbon atoms, such as benzyl (meth) acrylate, phenylethyl (meth) acrylate, methylbenzyl (meth) acrylate, and naphthylmethyl (meth) acrylate. Examples include (meth) acrylate, but the present invention is not limited to only such examples. These aralkyl (meth) acrylates may be used alone or in combination of two or more.

  Examples of the polyfunctional monomer include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, ethylene oxide-modified 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, propylene oxide-modified neopentyl glycol di (meth) acrylate, Di (meth) acrylate of a polyhydric alcohol having 1 to 10 carbon atoms such as tripropylene glycol di (meth) acrylate; addition mole number of polyethylene glycol di (meth) acrylate and propylene oxide having 2 to 50 ethylene oxide moles Is 2 Alkyl di (meth) acrylate having 2 to 50 carbon atoms, such as polypropylene glycol di (meth) acrylate and tripropylene glycol di (meth) acrylate, having an addition mole number of 2 to 50; ethoxylated glycerin tri ( (Meth) acrylate, propylene oxide-modified glycerol tri (meth) acrylate, ethylene oxide-modified trimethylolpropanetri (meth) acrylate, trimethylolpropanetri (meth) acrylate, pentaerythritol monohydroxytri (meth) acrylate, trimethylolpropanetriethoxytri Tri (meth) acrylate of a polyhydric alcohol having 1 to 10 carbon atoms such as (meth) acrylate; pentaerythritol tetra (meth) acrylate, dipentaery Tetra (meth) acrylate of a polyhydric alcohol having 1 to 10 carbon atoms such as litoltetra (meth) acrylate and ditrimethylolpropanetetra (meth) acrylate; pentaerythritol penta (meth) acrylate, dipentaerythritol (monohydroxy) penta (meth) A) penta (meth) acrylate of a polyhydric alcohol having 1 to 10 carbon atoms such as acrylate; hexa (meth) acrylate of a polyhydric alcohol having 1 to 10 carbon atoms such as pentaerythritol hexa (meth) acrylate; bisphenol A di (meth) A) acrylate, 2- (2'-vinyloxyethoxyethyl) (meth) acrylate, epoxy (meth) acrylate containing epoxy group such as epoxy (meth) acrylate; polyfunctional (meth) acrylate such as urethane (meth) acrylate Although acrylates and the like are mentioned, the present invention is not limited to only such examples. These polyfunctional monomers may be used alone or in combination of two or more.

  Among the monofunctional monomers used for the monomer component (I), from the viewpoint of forming a thick coating film having excellent pattern retention, weather resistance and discoloration resistance, alkyl (meth) acrylate, hydroxyl group Contained (meth) acrylates and styrene monomers are preferred, alkyl (meth) acrylates and styrene monomers are more preferred, and alkyl (meth) acrylates are even more preferred. Among the alkyl (meth) acrylates, alkyl (meth) acrylates having 1 to 12 carbon atoms in the alkyl group are preferred from the viewpoint of forming a thick coating film having excellent pattern retention, weather resistance and discoloration resistance. Preferably, an alkyl (meth) acrylate having 1 to 8 carbon atoms in the alkyl group is more preferred. Among the styrene monomers, styrene is preferred from the viewpoint of forming a coating film having excellent pattern retention, weather resistance and discoloration resistance as a thick film.

  The amount of the monomer component (I) is adjusted so as to be 35 to 80% by mass of all the monomer components used in the multistage emulsion polymerization. The amount of the monomer component (I) is 35% by mass of all the monomer components used in the multistage emulsion polymerization, from the viewpoint of forming a coating film having excellent pattern retention, weather resistance and discoloration resistance as a thick film. % Or more, preferably 40% by mass or more, and from the viewpoint of forming a coating film having excellent pattern retention, weather resistance and discoloration resistance as a thick film, 80% by mass or less, preferably 75% by mass or less, more preferably Is 70% by mass or less.

  Examples of the emulsion polymerization method of the monomer component (I) include, for example, a one-stage emulsion polymerization method in which a monomer component (I) containing an acid group-containing monomer is emulsion-polymerized (hereinafter, a one-stage emulsion polymerization method). Using a monomer component (Ia) which may contain an acid group-containing monomer and a monomer component (Ib) containing an acid group-containing monomer as the monomer component (I). The emulsion polymerization of the monomer component (Ia) followed by the emulsion polymerization of the monomer component (Ib) includes a two-stage emulsion polymerization method (hereinafter referred to as a two-stage emulsion polymerization method). Is not limited only to such an example. Among these emulsion polymerization methods, a two-stage emulsion polymerization method is preferred from the viewpoint of forming a thick coating film having excellent pattern retention, weather resistance and discoloration resistance.

  First, a method of performing emulsion polymerization of the monomer component (I) by a one-stage emulsion polymerization method will be described.

  In the one-stage emulsion polymerization method, the monomer component (I) is emulsion-polymerized at a pH of 1 to 5. The pH at the time of emulsion polymerization of the monomer component (I) is 1 or more, preferably 1.5 or more, from the viewpoint of forming a coating film excellent in pattern retention, weather resistance and discoloration resistance as a thick film. It is more preferably 2 or more, and still more preferably 2.5 or more. From the viewpoint of forming a coating film having excellent pattern retention, weather resistance and discoloration resistance as a thick film, 5 or less, preferably 4.5 or less, It is more preferably 4 or less, further preferably 3.5 or less, and still more preferably 3 or less.

  As a method of adjusting the pH at the time of emulsion polymerization of the monomer component (I), for example, a method of adjusting the pH of a medium used at the time of emulsion polymerization, used for the monomer component (I) A method of adjusting the pH by selecting the type and amount of the monomer, a method of mixing the monomer component (I) and the medium, and then adjusting the pH of the obtained mixture with a pH adjuster, and the like. However, the present invention is not limited to only such examples.

  As a method of emulsion polymerization of the monomer component (I), for example, an aqueous medium containing water and a water-soluble organic solvent such as a lower alcohol such as methanol, an emulsifier is dissolved in a medium such as water, and stirred. The method of dropping a monomer 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, include the present invention. It is not limited only to the method. In addition, the amount of the medium may be appropriately set in consideration of the amount of nonvolatile components contained in the obtained aqueous resin dispersion. The medium may be charged in the reaction vessel in advance, or may be used as a pre-emulsion. In addition, the medium may be used when the monomer component is emulsion-polymerized to produce an aqueous resin dispersion, if necessary.

  When emulsion-polymerizing the monomer component, the emulsion polymerization may be performed after the monomer component, the emulsifier and the medium are mixed, and the monomer component, the emulsifier and the medium are emulsified by stirring, and the pre-emulsion is performed. The emulsion polymerization may be carried out after the preparation of the above, or the emulsion polymerization may be carried out by mixing at least one of the monomer component, the emulsifier and the medium with the remaining pre-emulsion. The monomer component, the emulsifier, and the medium may be added all at once, may be added in portions, or may be continuously dropped.

  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, sodium dodecyl sulfonate and sodium alkyl diphenyl ether disulfonate; ammonium dodecyl benzene sulfonate and sodium dodecyl naphthalene sulfonate Alkyl aryl sulfonate salt; polyoxyethylene alkyl sulfonate salt; polyoxyethylene alkyl sulfate salt; polyoxyethylene alkyl aryl sulfate salt; dialkyl sulfosuccinate; aryl sulfonic acid-formalin condensate; Fatty acid salts; bis ( (Polyoxyethylene polycyclic phenyl ether) methacrylate sulfonate salt, propenyl-alkyl sulfosuccinate ester salt, (meth) acrylic acid polyoxyethylene sulfonate salt, (meth) acrylic acid polyoxyethylene phosphonate salt, allyloxymethyl alkyloxy poly Sulfate esters having an allyl group such as sulfonate salts of oxyethylene or salts thereof; sulfate salts of allyloxymethylalkoxyethyl polyoxyethylene, ammonium salts of polyoxyalkylene alkenyl ether sulfate, and the like. However, the present invention is not limited to this.

  As nonionic emulsifiers, 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 Examples thereof include a condensation product with an amine, allyloxymethylalkoxyethylhydroxypolyoxyethylene, polyoxyalkylenealkenyl ether, and the like, but the present invention is not limited to such examples.

  Examples of the cationic emulsifier include an alkylammonium salt such as dodecylammonium chloride and the like, but the present invention is not limited only to such examples.

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

  Examples of the polymer emulsifier include poly (meth) acrylates such as sodium polyacrylate; polyvinyl alcohol; polyvinylpyrrolidone; polyhydroxyalkyl (meth) acrylates such as polyhydroxyethyl acrylate; Examples include copolymers having at least one of the monomers as a copolymer component, but the present invention is not limited to such examples.

  Further, as the emulsifier, an emulsifier having a polymerizable group, that is, a so-called reactive emulsifier is preferable from the viewpoint of improving weather resistance, and a non-nonylphenyl type emulsifier is preferable from the viewpoint of environmental protection.

  As the reactive emulsifier, for example, a propenyl-alkyl sulfosuccinate salt, a (meth) acrylic acid polyoxyethylene sulfonate salt, a (meth) acrylic acid polyoxyethylene phosphonate salt [for example, manufactured by Sanyo Chemical Industries, Ltd .; Trade name: Eleminol RS-30, etc.), polyoxyethylene alkylpropenyl phenyl ether sulfonate salt (eg, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade names: Aqualon BC-10, Aqualon HS-10, etc.), allyloxymethyl alkyl Sulfonate salt of oxypolyoxyethylene [eg, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon KH-10, etc.], sulfonate salt of allyloxymethyl nonylphenoxyethyl hydroxypolyoxyethylene [eg, manufactured by ADEKA Corporation , Product Name: Ade Rear soap SE-10, etc.), allyloxymethylalkoxyethyl hydroxy polyoxyethylene sulfate ester salt (for example, manufactured by ADEKA, trade name: Adecaria soap SR-10, SR-30, etc.), bis (polyoxyethylene (Cyclic phenyl ether) methacrylated sulfonate salt (eg, manufactured by Nippon Emulsifier Co., Ltd., trade name: Antox MS-60, etc.), allyloxymethylalkoxyethylhydroxypolyoxyethylene [eg, manufactured by ADEKA Corporation, trade name: Adecaria soap ER-20, etc.), polyoxyethylene alkylpropenyl phenyl ether [eg, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon RN-20, etc.], allyloxymethyl nonylphenoxyethyl hydroxy polyoxyethylene [eg. , Ltd.) ADEKA Corporation, trade name: Adeka such REASOAP NE-10) but the like, the present invention is not limited only to those exemplified.

  The amount of the emulsifier is preferably at least 0.5 part by mass, more preferably at least 1 part by mass, further preferably at least 2 parts by mass, particularly preferably at least 2 parts by mass, from the viewpoint of improving the polymerization stability per 100 parts by mass of the monomer component. Is at least 3 parts by mass, and from the viewpoint of improving weather resistance, is preferably at most 10 parts by mass, more preferably at most 6 parts by mass, further preferably at most 5 parts by mass, particularly preferably at most 4 parts by mass.

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

  The amount of the polymerization initiator is preferably 0.05 part by mass or more, more preferably 0 part by mass, per 100 parts by mass of the monomer component, from the viewpoint of increasing the polymerization rate and reducing the residual amount of the unreacted monomer component. 0.1 part by mass or more, from the viewpoint of improving weather resistance, preferably 1 part by mass or less, more preferably 0.5 part 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 dropping. From the viewpoint of accelerating the termination of the polymerization reaction, a part of the polymerization initiator may be added before or after the addition of the monomer component into the reaction system.

  In order to promote the decomposition of the polymerization initiator, for example, a reducing agent such as sodium hydrogen sulfite, a polymerization initiator decomposing agent such as a transition metal salt such as ferrous sulfate is added to the reaction system in an appropriate amount. Is also good.

  In addition, a chain transfer agent can be used to adjust the weight average molecular weight of the polymer. Examples of the chain transfer agent include 2-ethylhexyl thioglycolate, tert-dodecyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, mercaptoacetic acid, mercaptopropionic acid, 2-mercaptoethanol, α-methylstyrene, α-methyl Styrene dimer and the like can be mentioned, but the present invention is not limited only to such an example. These chain transfer agents may be used alone or in combination of two or more. From the viewpoint of adjusting the weight average molecular weight of the emulsion particles, the amount of the chain transfer agent is preferably 0.01 to 10 parts by mass per 100 parts by mass of the monomer component.

  Further, when emulsion-polymerizing the monomer component, an appropriate amount of a silane coupling agent may be used from the viewpoint of improving weather resistance. Examples of the silane coupling agent include, for example, a silane coupling agent having a polymerizable unsaturated bond such as a (meth) acryloyl group, a vinyl group, an allyl group, and a propenyl group. It is not limited.

  In addition, when the monomer component (I) is emulsion-polymerized, additives such as a chelating agent, a film-forming aid, and a pH buffer may be added to the reaction system, if necessary. Since the amount of the additive varies depending on the type thereof, it cannot be determined unconditionally, but is usually about 0.01 to 5 parts by mass, more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the monomer component. It is about 3 parts by mass.

  The atmosphere in which the monomer component (I) is emulsion-polymerized 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.

  The polymerization temperature at the time of emulsion polymerization of the monomer component (I) is not particularly limited, but is usually preferably 50 to 100 ° C, more preferably 60 to 85 ° C. The polymerization temperature may be constant or may be changed during the polymerization reaction.

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

  As described above, the resin component emulsion (I) can be obtained by emulsion-polymerizing the monomer component (I) by one-stage emulsion polymerization. Emulsion particles contained in the resin emulsion (I) constitute an inner layer.

  Next, a method of emulsion-polymerizing the monomer component (I) by a two-stage emulsion polymerization method will be described.

  When the emulsion polymerization of the monomer component (I) is emulsion-polymerized by a two-stage emulsion polymerization method, the monomer component (Ia) may contain an acid group-containing monomer as the monomer component (I). ) And a monomer component (Ib) containing an acid group-containing monomer, and after the emulsion polymerization of the monomer component (Ia), the emulsion polymerization of the monomer component (Ib) results in a resin. Emulsion (I) can be obtained.

  Examples of the monomer used for the monomer component (Ia) include monomers used for the one-stage emulsion polymerization method. The monomer component (Ia) may contain an acid group-containing monomer or may not contain an acid group-containing monomer.

  The monomer component (Ia) includes a monofunctional monomer and a polyfunctional monomer. The monofunctional monomer and the polyfunctional monomer may be used alone or in combination.

  Examples of the monofunctional monomer used for the monomer component (Ia) include, for example, an ethylenically unsaturated double bond-containing monomer, but the present invention is not limited only to such examples. . Examples of the ethylenically unsaturated double bond-containing monomer include, for example, an acid group-containing monomer, an alkyl (meth) acrylate, a hydroxyl group-containing (meth) acrylate, a piperidyl group-containing monomer, an oxo group-containing monomer, Fluorine atom-containing monomer, nitrogen atom-containing monomer, epoxy group-containing monomer, alkoxyalkyl (meth) acrylate, silane group-containing monomer, carbonyl group-containing monomer, aziridinyl group-containing monomer, styrene Examples include monomers used in a one-stage emulsion polymerization method such as a system monomer and aralkyl (meth) acrylate, but the present invention is not limited only to such examples. These ethylenically unsaturated double bond-containing monomers may be used alone or in combination of two or more.

  Among the monomer components (Ia), from the viewpoint of forming a coating film having excellent pattern retention, weather resistance and discoloration resistance as a thick film, an acid group-containing monomer, an alkyl (meth) acrylate, and a hydroxyl group-containing (Meth) acrylates and styrene monomers are preferred, alkyl (meth) acrylates and styrene monomers are more preferred, and alkyl (meth) acrylates are even more preferred. Among the alkyl (meth) acrylates, alkyl (meth) acrylates having 1 to 18 carbon atoms in the alkyl group are preferable from the viewpoint of forming a thick coating film having excellent pattern retention, weather resistance and discoloration resistance. And an alkyl (meth) acrylate having 4 to 12 carbon atoms in the alkyl group is more preferable. These monomers may be used alone or in combination of two or more. In the present invention, as described above, the alkyl (meth) acrylate is a concept including the (meth) acrylate having an alicyclic structure.

  The method of emulsion-polymerizing the monomer component (Ia) is preferably the same as the one-stage emulsion polymerization method.

  After the monomer component (Ia) is emulsion-polymerized, the monomer component (Ib) is emulsion-polymerized. The monomer component (Ib) is the same as the monomer component used in the one-stage emulsion polymerization method. Therefore, as the monomer component (Ib), a monomer component containing an acid group-containing monomer is used as in the one-stage emulsion polymerization method.

  The method of emulsion-polymerizing the monomer component (Ib) is preferably the same as the one-stage emulsion polymerization method.

  In the two-stage emulsion polymerization method, the mass ratio of the monomer component (Ia) to the monomer component (Ib) [monomer component (Ia) / monomer component (Ib)] is determined by the pattern retention property. The thickness is preferably 15/85 to 60/40, more preferably 20/80 to 55/45, from the viewpoint of forming a coating film having excellent overall weather resistance and discoloration resistance as a thick film.

  After the monomer component (Ia) is emulsion-polymerized as described above, the resin emulsion (I) can be obtained by a two-stage emulsion polymerization method in which the monomer component (Ib) is emulsion-polymerized. The emulsion particles contained in the resin emulsion (I) constitute the inner layer as described above.

  Next, the pH of the resin emulsion (I) obtained above is adjusted to 6 to 10. In the present invention, since the operation of adjusting the pH of the resin emulsion (I) to 6 to 10 is employed, the monomer component (I) contains an acid group-containing monomer, A coating film having excellent retention, weather resistance and discoloration resistance can be formed as a thick film.

  The pH of the resin emulsion (I) is 6 or more, preferably 6.5 or more, more preferably 7 or more, from the viewpoint of forming a thick coating film having excellent pattern retention, weather resistance and discoloration resistance. It is preferably at least 7.5, and from the viewpoint of forming a coating film having excellent pattern retention, weather resistance and discoloration resistance as a thick film, it is at most 10 and preferably at most 9.5.

  The pH of the resin emulsion (I) can be adjusted, for example, by adding a basic compound to the resin emulsion (I).

  As the basic compound, for example, ammonia, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, calcium hydroxide, alkaline earth metal hydroxides such as barium hydroxide, sodium hydrogen carbonate, monomethylamine and the like Examples include amine compounds, but the present invention is not limited to only such examples. These basic compounds may be used alone or in combination of two or more. Among these basic compounds, ammonia is preferred from the viewpoint of forming a thick coating film having excellent pattern retention, weather resistance and discoloration resistance. Ammonia can usually be used in the form of an aqueous solution of about 5 to 30% by mass.

  When adjusting the pH of the resin emulsion (I), the liquid temperature of the resin emulsion (I) is not particularly limited, but is usually preferably about room temperature to about 95 ° C.

  In the present invention, as the emulsion particles constituting the inner layer, using emulsion particles obtained by emulsion polymerization in advance, the emulsion polymerization of the monomer component (I) in the presence of the emulsion particles may be performed. Good. When emulsion polymerization is performed in this manner, the emulsion particles obtained by emulsion polymerization of the monomer component (I) have a resin layer at the center and emulsify the monomer component (I) on the surface thereof. A resin layer made of a polymer obtained by polymerization is formed. The monomer component and the emulsion polymerization method when forming the resin layer in the center may be the same as the emulsion polymerization of the monomer component (I) or the emulsion polymerization of the monomer component (II) described below. preferable.

  Further, in the present invention, after performing the emulsion polymerization of the monomer component (I), before performing the emulsion polymerization of the monomer component (II), if necessary, to form a resin layer of the intermediate layer. Emulsion polymerization of other monomer components may be performed. When emulsion polymerization of other monomer components is performed to form the intermediate resin layer, the obtained emulsion particles have the intermediate resin layer between the inner layer and the outer layer. The monomer component and the emulsion polymerization method when forming the intermediate resin layer are preferably the same as the emulsion polymerization of the monomer component (I).

  On the surface of the emulsion particles contained in the resin emulsion used when performing the emulsion polymerization of the monomer component (II), a resin layer composed of the monomer component (I) is formed, which has a pattern retention property. It is preferable from the viewpoint of forming a coating film excellent in weather resistance and discoloration resistance as a thick film.

  Next, after adjusting the pH of the resin emulsion (I) to a predetermined value, the monomer component (II) in an amount of 20 to 65% by mass of all the monomer components used in the multi-stage emulsion polymerization is added to the resin emulsion ( The monomer component (II) is added to (I) and emulsion-polymerized.

  In the present invention, the emulsion polymerization of the monomer component (II) may be carried out after the polymerization reaction rate in the emulsion polymerization of the monomer component (I) reaches 90% or more, preferably 95% or more. From the viewpoint of forming a layer separation structure.

  Examples of the monomer component (II) include a monofunctional monomer and a polyfunctional monomer used in emulsion polymerization of the monomer component (I).

  Among the monofunctional monomers, alkyl (meth) acrylates, hydroxyl group-containing (meth) acrylates and styrene-based monomers are used from the viewpoint of forming a thick film having excellent pattern retention, weather resistance and discoloration resistance. Preferred are alkyl (meth) acrylates and hydroxyl group-containing (meth) acrylates, and more preferred are alkyl (meth) acrylates. Among the alkyl (meth) acrylates, alkyl (meth) acrylates having 1 to 12 carbon atoms in the alkyl group are preferred from the viewpoint of forming a thick coating film having excellent pattern retention, weather resistance and discoloration resistance. Preferably, an alkyl (meth) acrylate having 1 to 8 carbon atoms in the alkyl group is more preferred. Among the hydroxyl group-containing (meth) acrylates, from the viewpoint of forming a coating film having excellent pattern retention, weather resistance and discoloration resistance as a thick film, hydroxyalkyl (meth) acrylate having a hydroxyalkyl group having 2 to 4 carbon atoms is preferred. ) Acrylates are preferred.

  From the viewpoint of improving the weather resistance, it is preferable that the monomer component (II) contains a monomer containing a UV-stable group, a monomer containing a UV-absorbing group, or the like. Among these monomers, from the viewpoint of forming a coating film having excellent pattern retention, weather resistance and discoloration resistance as a thick film, a monomer having a UV-stable group is preferred.

  Examples of the UV-stable group-containing monomer include a (meth) acryloyl group-containing piperidine compound. Examples of the (meth) acryloyl group-containing piperidine compound include 4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine and 4- (meth) acryloylamino-2,2,6,6-tetra. Methylpiperidine, 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, -Crotonoylamino-2,2,6,6-tetramethylpiperidine, 4- (meth) acryloylamino-1,2,2,6,6-pentame Lupiperidine, 4-cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl Examples of (meth) such as -4-cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine ) Acryloyl group-containing piperidine compounds and the like, but the present invention is not limited to only such examples. These monomers may be used alone or in combination of two or more. Among these monomers, 4- (meth) acryloyloxy-2,2,2 is preferred from the viewpoint of forming a coating film which is totally excellent in weather resistance, freezing fluid retention, pattern retention and deformation resistance. 6,6-tetramethylpiperidine, 4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4- (meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine, Piperidine containing a (meth) acryloyloxyamino group such as 4- (meth) acryloyl-1-methoxy-2,2,6,6-tetramethylpiperidine is preferred.

  The content of the ultraviolet light stable group-containing monomer in the monomer component (II) is preferably 0.5% by mass or more, more preferably from the viewpoint of forming a coating film having excellent weather resistance and discoloration resistance. The content is 1% by mass or more, more preferably 1.2% by mass or more, and preferably 8% by mass or less, more preferably 5% by mass or less, from the viewpoint of forming a coating film having excellent pattern retention.

  Examples of the UV-absorbing group-containing monomer include, for example, a benzotriazole-based UV-absorbing group-containing monomer and a benzophenone-based UV-absorbing group-containing monomer, but the present invention is limited to only such examples. It is not something to be done. These monomers may be used alone or in combination of two or more.

  Examples of the benzotriazole-based UV-absorbing group-containing monomer include 2- [2′-hydroxy-5 ′-(meth) acryloyloxymethylphenyl] -2H-benzotriazole and 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 -Benzotriazole, 2- [2'-hydroxy-5 '-(meth) acryloyloxy Hexylphenyl] -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) acryloyloxy Ethylphenyl] -2H-benzotriazole, 2- [2'-hydroxy-5 '-(meth) acryloyloxyethylphenyl] -5-chloro-2H-benzotriazole, 2- [2'-hydroxy-5'-( Meth) acryloyloxyethylphenyl] -5-cyano-2H-benzotriazole, 2- [2 ′ Hydroxy-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 only to such examples. These monomers may be used alone or in combination of two or more.

  Examples of the benzophenone-based UV-absorbing group-containing 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- Examples thereof include 4- [2- (meth) acryloyloxy] butoxybenzophenone, and the like, but the present invention is not limited to only such examples. These monomers may be used alone or in combination of two or more.

  The content of the UV-absorbing group-containing monomer in the monomer component (II) is preferably 0.5% by mass or more, more preferably from the viewpoint of forming a coating film having excellent weather resistance and discoloration resistance. The content is 1% by mass or more, more preferably 1.2% by mass or more, and preferably 8% by mass or less, more preferably 5% by mass or less, from the viewpoint of forming a coating film having excellent pattern retention.

  Further, the content of the acid group-containing monomer in the monomer component (II) is preferably 0.3% by mass or less, more preferably from the viewpoint of improving the polymerization stability of the monomer component (II). It is 0.1% by mass or less, further preferably 0.05% by mass or less, particularly preferably 0% by mass. Examples of the acid group-containing monomer include those similar to the acid group-containing monomer used in the monomer component (II).

  The amount of the monomer component (II) is adjusted so as to be 20 to 65% by mass of all the monomer components used in the multistage emulsion polymerization. The amount of the monomer component (II) is 20% by mass of all the monomer components used in the multi-stage emulsion polymerization, from the viewpoint of forming a thick film having excellent pattern retention, weather resistance and discoloration resistance. %, Preferably 25% by mass or more, more preferably 30% by mass or more, and from the viewpoint of forming a coating film excellent in pattern retention, weather resistance and discoloration resistance as a thick film, 65% by mass or less, preferably Is 60% by mass or less.

  When the monomer component (II) is added to the resin emulsion (I) and the monomer component (II) is emulsion-polymerized, the method of emulsion-polymerizing the monomer component (II) is performed by the monomer component (I ) Is preferably the same as the method for emulsion polymerization.

  As described above, the resin component (II) can be obtained by adding the monomer component (II) to the resin emulsion (I) and emulsion-polymerizing the monomer component (II).

  Next, the pH of the resin emulsion (II) obtained above is increased. In the present invention, there is one major feature in that the pH of the resin emulsion (II) is further increased. In the present invention, since this operation is employed, a coating film having excellent pattern retention, weather resistance and discoloration resistance can be formed as a thick film.

  From the viewpoint of forming a coating film having excellent pattern retention, weather resistance and discoloration resistance as a thick film, it is preferable to increase the pH of the resin emulsion (II) by 0.5 to 2 and the pH of the resin emulsion (II). Is more preferably increased by 0.8 to 1.5.

  The pH of the resin emulsion (II) can be adjusted, for example, by adding a basic compound to the resin emulsion (II).

  Examples of the basic compound include those similar to the basic compound used in the resin emulsion (I). More specifically, examples of the basic compound include ammonia, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkaline earth metal hydroxides such as calcium hydroxide and barium hydroxide, hydrogen carbonate Examples thereof include amine compounds such as sodium and monomethylamine, but the present invention is not limited to only such examples. These basic compounds may be used alone or in combination of two or more. Among these basic compounds, ammonia is preferred from the viewpoint of forming a thick coating film having excellent pattern retention, weather resistance and discoloration resistance. Ammonia can usually be used in the form of an aqueous solution of about 5 to 30% by mass.

  When adjusting the pH of the resin emulsion (II), the liquid temperature of the resin emulsion (II) is not particularly limited, but is usually preferably room temperature to 95 ° C., and the pattern retention, weather resistance and discoloration resistance are improved. From the viewpoint of forming an excellent coating film as a thick film, the temperature is more preferably from 50 to 90 ° C, even more preferably from 60 to 85 ° C.

  By adjusting the pH of the resin emulsion (II) as described above, an aqueous resin dispersion can be obtained. The aqueous resin dispersion may contain emulsion particles such as emulsion particles made of another resin and emulsion particles obtained by one-stage emulsion polymerization, as long as the object of the present invention is not impaired.

  The number of resin layers contained in the emulsion particles contained in the aqueous resin dispersion is preferably 2 to 5 layers from the viewpoint of forming a coating film having excellent overall pattern retention, weather resistance and discoloration resistance as a thick film. , More preferably 2 to 4 layers, further preferably 2 or 3 layers, still more preferably 3 layers.

  When the emulsion particles have a two-layer structure of an inner layer made of a polymer obtained by emulsion polymerization of the monomer component (I) and an outer layer made of a polymer obtained by emulsion polymerization of the monomer component (II), the pattern is maintained. It is preferable that only the monomer component (I) contains an acid group-containing monomer from the viewpoint of forming a coating film having excellent properties, weather resistance and discoloration resistance as a thick film.

  The emulsion particles have an inner layer made of a polymer obtained by emulsion polymerization of the monomer component (I) and an outer layer made of a polymer obtained by emulsion polymerization of the monomer component (II), and the inner layer has a monomer component. When the emulsion component is formed by emulsion polymerization of the monomer component (I) by two-stage emulsion polymerization using (Ia) and the monomer component (Ib), the emulsion particles form a resin layer having a three-layer structure. Have. In the emulsion particles having the three-layered resin layer, the monomer component (Ia) and the monomer component (Ia) are used from the viewpoint of forming a thick coating film having overall excellent pattern retention, weather resistance and discoloration resistance. The monomer component (Ib) of the body component (Ib) preferably contains an acid group-containing monomer.

  The total content of the monomer component (I) and the monomer component (II) in all the monomer components used in the multi-stage emulsion polymerization is a coating film excellent in pattern retention, weather resistance and discoloration resistance. Is preferably 60 to 100% by mass, more preferably 65 to 100% by mass, further preferably 70 to 100% by mass, and still more preferably 80 to 100% by mass from the viewpoint of forming a thick film.

  If necessary, another resin layer may be formed inside the inner layer of the emulsion particles, between the inner layer and the outer layer, or on the surface of the outer layer as long as the object of the present invention is not impaired.

  The glass transition temperature of the entire resin layer constituting the emulsion particles is preferably 50 ° C. or lower, more preferably 45 ° C. or lower, and still more preferably 40 ° C. or lower, from the viewpoint of improving the film formability, and increases the coating film strength. From the viewpoint, the temperature is preferably -40 ° C or higher, more preferably -25 ° C or higher, and further preferably -10 ° C or higher. The glass transition temperature of the polymer can be easily adjusted by adjusting the composition of the monomer used for the monomer component.

In the present specification, the glass transition temperature of a polymer is calculated by using the glass transition temperature of a homopolymer of a monomer used for a monomer component constituting the polymer, and is represented by the following formula:
1 / Tg = Σ (Wm / Tgm) / 100
[Wherein, Wm represents the content (% by mass) of the monomer m in the monomer components constituting the polymer, and Tgm represents the glass transition temperature (absolute temperature: K) of the homopolymer of the monomer m. ]
Means the temperature determined based on the Fox equation represented by

  The glass transition temperature of the polymer is, for example, 95 ° C. for a homopolymer of acrylic acid, 130 ° C. for a homopolymer of methacrylic acid, 105 ° C. for a homopolymer of methyl methacrylate, 100 ° C. for a homopolymer of styrene, and cyclohexyl. 83 ° C. for a methacrylate homopolymer, −70 ° C. for a 2-ethylhexyl acrylate homopolymer, 55 ° C. for a 2-hydroxyethyl methacrylate homopolymer, −56 ° C. for a n-butyl acrylate homopolymer, 4- 130 ° C. for a homopolymer of methacryloyloxy-1,2,2,6,6-pentamethylpiperidine, 130 ° C. for a homopolymer of 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine. 70 ° C. for a homopolymer of methacryloyloxypropyltrimethoxysilane.

  The glass transition temperature of the polymer is a value determined based on the Fox equation, and the measured value of the glass transition temperature of the polymer is determined based on the Fox equation. It is preferably the same as the value. The measured value of the glass transition temperature of the polymer can be determined, for example, by measuring its differential scanning calorimetry.

  In the present specification, the glass transition temperature of the polymer means the glass transition temperature determined based on the above formula, unless otherwise specified. For monomers whose glass transition temperature is unknown, such as special monomers and polyfunctional monomers, the total amount of the monomers whose glass transition temperature is unknown in the monomer component is 10% by mass. In the following cases, the glass transition temperature is determined using only the monomer whose glass transition temperature is known. When the total amount of the monomers whose glass transition temperature is unknown in the monomer component exceeds 10% by mass, the glass transition temperature of the polymer is determined by differential scanning calorimetry (DSC), differential calorimetry (DTA), It is determined by thermomechanical analysis (TMA) or the like.

  As an apparatus for measuring the differential scanning calorific value, for example, Seiko Instruments Co., Ltd., product number: DSC220C and the like can be mentioned. When measuring the differential scanning calorific value, a method of drawing a differential scanning calorific value (DSC) curve, a method of obtaining a first-order differential curve from the differential scanning caloric value (DSC) curve, a method of performing a smoothing process, and a method of determining a target peak temperature There is no particular limitation on the like. For example, when the measurement device is used, the drawing may be performed from data obtained by using the measurement device. At that time, analysis software capable of performing mathematical processing can be used. Examples of the analysis software include, for example, analysis software (manufactured by Seiko Instruments Inc., product number: EXSTAR6000), but the present invention is not limited to only such examples. Note that the peak temperature obtained in this manner may include an error due to drawing about 5 ° C. in the upper and lower directions.

  The content of the acid group-containing monomer in all the monomer components used in the multi-stage emulsion polymerization is preferably from the viewpoint of forming a thick coating film having excellent pattern retention, weather resistance and discoloration resistance. 0.3% by mass or more, more preferably 0.5% by mass or more, from the viewpoint of forming a coating film excellent in pattern retention, weather resistance and discoloration resistance with a thick film, preferably 5% by mass or less, It is more preferably at most 3% by mass.

  The mass ratio of the polymer obtained by emulsion polymerization of the monomer component (I) constituting the inner layer of the emulsion particles to the polymer obtained by emulsion polymerization of the monomer component (II) constituting the outer layer (constituting the inner layer) Polymer / polymer constituting outer layer] is at least 35/65, preferably at least 40/60, from the viewpoint of forming a coating film having excellent pattern retention, weather resistance and discoloration resistance as a thick film. It is 80/20 or less, preferably 75/25 or less from the viewpoint of forming a coating film having excellent pattern retention, weather resistance and discoloration resistance as a thick film.

  The total content of the polymer obtained by emulsion polymerization of the monomer component (I) constituting the inner layer and the polymer obtained by emulsion polymerization of the monomer component (II) constituting the outer layer in the emulsion particles is a pattern. From the viewpoint of forming a coating film having excellent retention, weather resistance and discoloration resistance as a thick film, preferably 60 to 100% by mass, more preferably 65 to 100% by mass, further preferably 70 to 100% by mass, and More preferably, it is 80 to 100% by mass.

  The non-volatile content in the aqueous resin dispersion 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, from the viewpoint of improving handleability. It is preferably at most 60% by mass.

In the present specification, the non-volatile content of the aqueous resin dispersion is determined by weighing 1 g of the aqueous resin dispersion, drying the resultant at a temperature of 110 ° C. for 1 hour with a hot-air dryer, and setting the obtained residue to a non-volatile content by the formula:
[Non-volatile content in water-based resin dispersion (% by mass)]
= ([Mass of residue] ÷ [1 g of aqueous resin dispersion]) × 100
Means the value obtained based on

  The average particle size of the emulsion particles is preferably 50 nm or more, more preferably 75 nm or more, and still more preferably 100 nm or more, from the viewpoint of forming a coating film having excellent pattern retention, weather resistance and discoloration resistance as a thick film. The thickness is preferably 300 nm or less, more preferably 280 nm or less, and still more preferably 250 nm or less, from the viewpoint of forming a thick coating film having excellent pattern retention, weather resistance and discoloration resistance.

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

The viscosity at 25 ° C. of the aqueous resin dispersion is preferably 300 mPa · s or more, more preferably 400 mPa · s or more, from the viewpoint of forming a thick film having excellent pattern retention, weather resistance and color fastness. It is more preferably at least 500 mPa · s, and from the viewpoint of improving coatability, preferably at most 2,000 mPa · s, more preferably at most 1,800 mPa · s, even more preferably at most 1,500 mPa · s. The viscosity of the aqueous resin dispersion is a value measured at a rotation speed of 30 min ^-1 using a BM type viscometer (for example, manufactured by Tokyo Keiki Co., Ltd.).

  Crosslinkability can be imparted to the aqueous resin dispersion by including a crosslinking agent. The crosslinking agent may be one that starts a crosslinking reaction at room temperature or one that starts a crosslinking reaction by heat. Examples of the crosslinking agent include oxazoline group-containing compounds, isocyanate group-containing compounds, aminoplast resins, and the like. These crosslinking agents may be used alone or in combination of two or more.

  In the present invention, in addition to the above-mentioned cross-linking agent, for example, a cross-linking agent such as a carbodiimide compound; a polyvalent metal compound represented by a zirconium compound, a zinc compound, a titanium compound, an aluminum compound, etc. It can be used as long as it is not inhibited.

  Aqueous resin dispersions include, for example, a film-forming aid, a plasticizer, a foam inhibitor, a pigment, a thickener, a matting agent, a dispersant, a wetting agent, and an ultraviolet absorber as long as the object of the present invention is not hindered. Additives such as agents, ultraviolet stabilizers, fillers, leveling agents, stabilizers, pigments, dyes, and antioxidants may be included in appropriate amounts.

  The aqueous resin dispersion can be suitably used for an aqueous paint. The aqueous paint contains the aqueous resin dispersion. The water-based paint may be composed of only the water-based resin dispersion, and as long as the object of the present invention is not hindered, for example, a film-forming aid, a plasticizer, a foam inhibitor, a pigment, a thickener, a matting agent. It may contain one or more of an agent, a dispersant, a wetting agent, an ultraviolet absorber, an ultraviolet stabilizer, a filler, a leveling agent, a stabilizer, a pigment, a dye, an antioxidant, and the like. Examples of the water-based paint include an enamel paint and a clear paint.

  The water-based paint may be applied alone in one layer, or may be applied by coating two or more layers. When coating is carried out by applying two or more layers, only a part of the layers may be formed by the water-based paint, or all the layers may be formed by the water-based paint. The overcoating is performed, for example, by applying a coating for a first layer (for example, an undercoat layer) to an object to be coated which has been subjected to a primer treatment or a sealer treatment, drying the coating, and then applying a coating for a second layer (for example, an overcoat layer). Examples include a method of overcoating and drying the paint, but the present invention is not limited by such a method. Examples of the method of applying the aqueous paint include, for example, a method of applying using a brush, a bar coater, an applicator, an air spray, an airless spray, a roll coater, a flow coater, and the like. Not something.

  The water-based paint can be suitably used, for example, when painting on the exterior wall of a building or the like, and can also be suitably used for an inorganic building material such as a ceramic building material. Examples of the ceramic building materials include tiles and outer wall materials. Ceramic building materials are obtained by adding an inorganic filler, a fibrous material, etc. to a hydraulic adhesive material that is a raw material of an inorganic cured product, molding the resulting mixture, curing the obtained molded product, and curing it. can get. Examples of the inorganic building material constituting the exterior of the building include a flexible board, a calcium silicate board, a gypsum slag perlite board, a wood chip cement board, a precast concrete board, an ALC board, and a gypsum board.

  Next, the present invention will be described in more detail based on examples, but the present invention is not limited to only these examples.

  In the following Examples and Comparative Examples, “parts” means “parts by mass” and “%” means “% by mass” unless otherwise specified.

Preparation Example 1
210 parts of deionized water, 60 parts of dispersant [trade name: Demol EP, manufactured by Kao Corporation], 50 parts of dispersant [trade name: Discoat N-14, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.], wetting agent [Kao Corporation, trade name: Emulgen LS-106] 10 parts, propylene glycol 60 parts, titanium oxide [Ishihara Sangyo Co., Ltd., product number: CR-95] 1000 parts and glass beads (diameter: 1 mm) 200 The mixture was dispersed with a homodisper at a rotation speed of 3000 min-1 for 60 minutes to prepare a white paste.

Example 1
527 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. 140 parts of deionized water and 48 parts of a 25% aqueous solution of an emulsifier [ADEKA Corporation, trade name: Adecaria Sorb SR-10], 240 parts of methyl methacrylate, 148 parts of 2-ethylhexyl acrylate and 12 parts of acrylic acid in a dropping funnel. To prepare a dropping pre-emulsion, and about 74 parts of the dropping pre-emulsion was added to the flask, and the temperature was raised to 70 ° C. while gently blowing nitrogen gas. After warming, 60 parts of a 5% aqueous solution of ammonium persulfate was added to initiate the polymerization reaction. Thereafter, the rest of the pre-emulsion for dropping was uniformly dropped into the flask over 70 minutes, and the content of the flask was maintained at 70 ° C. for 60 minutes, thereby completing the emulsion polymerization of the monomer component (I). When the pH of the contents of the flask was examined, the pH was 2.8. This confirmed that the emulsion polymerization of the monomer component (I) was performed at a pH of about 2.8.

  In each example and each comparative example, a pH measurement device [trade name: Castany LAB pH / ion meter, manufactured by HORIBA, Ltd.] was used for pH measurement.

  Next, the content of the flask was maintained at 70 ° C. for 10 minutes, and then the pH of the content of the flask was adjusted to 7.8 by adding 25% aqueous ammonia into the flask.

  After maintaining the contents of the flask at 70 ° C. for 60 minutes, 210 parts of deionized water, 72 parts of a 25% aqueous solution of an emulsifier (trade name: ADEKA SORB SR-10, manufactured by ADEKA Corporation), 350 parts of methyl methacrylate, The dropping pre-emulsion obtained by mixing 237 parts of 2-ethylhexyl acrylate and 13 parts of 4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine with a monomer component (II) was used. The prepared pre-emulsion for dropping was prepared and uniformly dropped into the flask over 110 minutes. After completion of the dropping, the emulsion polymerization of the monomer component (II) was completed by maintaining the contents of the flask at 70 ° C. for 60 minutes. When the pH of the contents of the flask was examined, the pH was 8.3.

  Next, the content of the flask was cooled to 40 ° C., 6.3 parts of 25% aqueous ammonia was added to the flask, and the mixture was filtered through a 100-mesh (JIS mesh, hereinafter the same) wire mesh to disperse the aqueous resin. A liquid was obtained. The resulting aqueous resin dispersion had a pH of 8.8.

  The content of non-volatile components in the aqueous resin dispersion obtained above is 50.1%, the content of the acid group-containing monomer (acrylic acid) in the monomer component (I) is 3%, The content of the acid group-containing monomer (acrylic acid) in all the monomer components was 1.2%, and the glass transition temperature of the entire polymer constituting the emulsion particles contained in the aqueous resin dispersion was Was 11 ° C., the average particle size of the emulsion particles was 180 nm, and the viscosity of the aqueous resin dispersion at 25 ° C. was 1000 mPa · s.

Next, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate [manufactured by JNC Co., Ltd., product number: CS-12] was added to 100 parts of the aqueous resin dispersion obtained above as a film forming aid. ], And stirred with a homodisper at a rotation speed of 1500 min ^{-1 for} 10 minutes, and then 30 parts of the white paste obtained in Preparation Example 1 and black paste [trade name: SK, manufactured by SK Chemical Co., Ltd.] Aqueous color (black)] 7 parts and an antifoaming agent [manufactured by San Nopco Co., Ltd., trade name: Nopco 8034L] 0.5 part were added, and a Krebs unit viscometer (manufactured by Brookfield, product number: KU-1) was added. Thickener [ADEKA Corporation, trade name: ADEKANOL UH-420] and [Nippon Shokubai Co., Ltd., trade name: ACRYSET WR-, so that the viscosity when measured at 25 ° C. becomes 80 KU. 503 About 1: added 1 ratio by stirring for 30 minutes in this state to obtain a water-based paint.

Example 2
527 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. 140 parts of deionized water, 48 parts of a 25% aqueous solution of an emulsifier [ADEKA Corporation, trade name: Adecariasorb SR-10], 255 parts of cyclohexyl methacrylate, 133 parts of 2-ethylhexyl acrylate, and 12 parts of acrylic acid in a dropping funnel. To prepare a dropping pre-emulsion, and about 74 parts of the dropping pre-emulsion was added to the flask, and the temperature was raised to 70 ° C. while gently blowing nitrogen gas. After warming, 60 parts of a 5% aqueous solution of ammonium persulfate was added to initiate the polymerization reaction. Thereafter, the rest of the pre-emulsion for dropping was uniformly dropped into the flask over 70 minutes, and the content of the flask was maintained at 70 ° C. for 60 minutes, thereby completing the emulsion polymerization of the monomer component (I). When the pH of the contents of the flask was examined, the pH was 2.9. From this, it was confirmed that the emulsion polymerization of the monomer component (I) was performed at a pH of about 2.9.

  Next, the content of the flask was maintained at 70 ° C. for 10 minutes, and then the pH of the content of the flask was adjusted to 8.0 by adding 25% aqueous ammonia into the flask.

  After maintaining the contents of the flask at 70 ° C. for 60 minutes, 210 parts of deionized water, 72 parts of a 25% aqueous solution of an emulsifier (trade name: ADEKA SORB SR-10, manufactured by ADEKA Corporation), 350 parts of methyl methacrylate, The dropping pre-emulsion obtained by mixing 237 parts of 2-ethylhexyl acrylate and 13 parts of 4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine with a monomer component (II) was used. The prepared pre-emulsion for dropping was prepared and uniformly dropped into the flask over 110 minutes. After completion of the dropping, the emulsion polymerization of the monomer component (II) was completed by maintaining the contents of the flask at 70 ° C. for 60 minutes. When the pH of the contents of the flask was checked, the pH was 8.6.

  Next, 6.3 parts of 25% ammonia water was added into the flask, and the obtained reaction solution was cooled to 40 ° C. and filtered through a 100-mesh wire net to obtain an aqueous resin dispersion. The pH of the resulting aqueous resin dispersion was 9.1.

  The content of non-volatile components in the aqueous resin dispersion obtained above is 50.1%, the content of the acid group-containing monomer (acrylic acid) in the monomer component (I) is 3%, The content of the acid group-containing monomer (acrylic acid) in all the monomer components was 1.2%, and the glass transition temperature of the entire polymer constituting the emulsion particles contained in the aqueous resin dispersion was Was 10 ° C., the average particle size of the emulsion particles was 180 nm, and the viscosity of the aqueous resin dispersion at 25 ° C. was 800 mPa · s.

Next, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate [manufactured by JNC Co., Ltd., product number: CS-12] was added to 100 parts of the aqueous resin dispersion obtained above as a film forming aid. ], And stirred with a homodisper at a rotation speed of 1500 min ^{-1 for} 10 minutes, and then 30 parts of the white paste obtained in Preparation Example 1 and black paste [trade name: SK, manufactured by SK Chemical Co., Ltd.] Aqueous color (black)] 7 parts and an antifoaming agent [manufactured by San Nopco Co., Ltd., trade name: Nopco 8034L] 0.5 part were added, and a Krebs unit viscometer (manufactured by Brookfield, product number: KU-1) was added. Thickener [ADEKA Corporation, trade name: ADEKANOL UH-420] and [Nippon Shokubai Co., Ltd., trade name: ACRYSET WR-, so that the viscosity when measured at 25 ° C. becomes 80 KU. 503 About 1: added 1 ratio by stirring for 30 minutes in this state to obtain a water-based paint.

Example 3
527 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. 87 parts of deionized water, 30 parts of a 25% aqueous solution of an emulsifier [ADEKA Corporation, trade name: Adecariasorb SR-10], and a monomer component (Ia) composed of 250 parts of cyclohexyl methacrylate are added to the dropping funnel. Thus, a dropping pre-emulsion was prepared, and about 74 parts of the dropping pre-emulsion was added to the flask, the temperature was raised to 80 ° C. while gently blowing nitrogen gas, and 60 parts of a 5% aqueous potassium persulfate solution was added. Was added to initiate the polymerization reaction. Thereafter, the rest of the pre-emulsion for dropping was uniformly dropped into the flask over 40 minutes, and the content of the flask was maintained at 80 ° C. for 60 minutes, thereby completing the emulsion polymerization of the monomer component (Ia). When the pH of the contents of the flask was examined, the pH was 2.6. From this, it was confirmed that the emulsion polymerization of the monomer component (Ia) was performed at a pH of about 2.6.

  Next, after maintaining the contents of the flask at 80 ° C. for 60 minutes, 175 parts of deionized water, 60 parts of a 25% aqueous solution of an emulsifier [ADEKA Corporation, trade name: Adecariasorb SR-10], and methyl methacrylate A dropping pre-emulsion obtained by mixing 200 parts, 290 parts of 2-ethylhexyl acrylate and a monomer component (Ib) composed of 10 parts of acrylic acid was prepared, and the obtained pre-emulsion for dropping was mixed for 90 minutes. , The emulsion polymerization of the monomer component (Ib) was carried out. Thereafter, when the pH of the contents of the flask was examined in the same manner as described above, the pH was 2.8.

  Next, the content of the flask was maintained at 80 ° C. for 10 minutes, and then the pH of the content of the flask was adjusted to 8.1 by adding 25% aqueous ammonia into the flask.

  After maintaining the contents of the flask at 80 ° C. for 60 minutes, 87 parts of deionized water, 30 parts of a 25% aqueous solution of an emulsifier [trade name: ADEKA SORB SR-10, manufactured by ADEKA Corporation], 150 parts of cyclohexyl methacrylate, It is obtained by mixing 80 parts of 2-ethylhexyl acrylate, 10 parts of 2-hydroxyethyl methacrylate and 10 parts of 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine with a monomer component (II). The third stage pre-emulsion for dripping was prepared, and the obtained pre-emulsion for dripping was uniformly dripped into the flask over 50 minutes. After the completion of the dropwise addition, the emulsion polymerization of the monomer component (II) was completed by maintaining the contents of the flask at 80 ° C. for 60 minutes. Upon examining the pH of the contents of the flask, the pH was found to be 8.5.

  Next, 5.0 parts of 25% aqueous ammonia was added into the flask, and the obtained reaction solution was cooled to 40 ° C. and filtered through a 100-mesh wire net to obtain an aqueous resin dispersion. The pH of the resulting aqueous resin dispersion was 9.0.

  The content of non-volatile components in the aqueous resin dispersion obtained above is 50.0%, the content of the acid group-containing monomer (acrylic acid) in the monomer component (Ia) is 0%, The content of the acid group-containing monomer (acrylic acid) in the monomer component (Ib) is 2%, and the monomer component (Ia) and the monomer component (Ib) The content of the acid group-containing monomer (acrylic acid) in I) was 1.3%, and the content of the acid group-containing monomer (acrylic acid) in all the monomer components was 1.0%. The glass transition temperature of the entire polymer constituting the emulsion particles contained in the aqueous resin dispersion is 8 ° C., the average particle size of the emulsion particles is 150 nm, and the viscosity of the aqueous resin dispersion at 25 ° C. Was 1500 mPa · s.

Next, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate [manufactured by JNC Co., Ltd., product number: CS-12] was added to 100 parts of the aqueous resin dispersion obtained above as a film forming aid. ], And stirred with a homodisper at a rotation speed of 1500 min ^{-1 for} 10 minutes, and then 30 parts of the white paste obtained in Preparation Example 1 and black paste [trade name: SK, manufactured by SK Chemical Co., Ltd.] Aqueous color (black)] 7 parts and an antifoaming agent [manufactured by San Nopco Co., Ltd., trade name: Nopco 8034L] 0.5 part were added, and a Krebs unit viscometer (manufactured by Brookfield, product number: KU-1) was added. Thickener [ADEKA Corporation, trade name: ADEKANOL UH-420] and [Nippon Shokubai Co., Ltd., trade name: ACRYSET WR-, so that the viscosity when measured at 25 ° C. becomes 80 KU. 503 About 1: added 1 ratio by stirring for 30 minutes in this state to obtain a water-based paint.

Example 4
527 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. 53 parts of deionized water, 18 parts of a 25% aqueous solution of an emulsifier [Adekariasorb SR-10], and a monomer component (Ia) comprising 150 parts of cyclohexyl methacrylate are added to the dropping funnel. Then, about 74 parts of the pre-emulsion for dropping was added to the flask, and the temperature was raised to 70 ° C. while gently blowing nitrogen gas, and 60 parts of an aqueous 5% ammonium persulfate solution was added. Then, the polymerization reaction was started. Thereafter, the remainder of the pre-emulsion for dropping was uniformly dropped into the flask over a period of 20 minutes, and the content of the flask was maintained at 70 ° C. for 60 minutes to complete the emulsion polymerization of the monomer component (Ia). When the pH of the contents of the flask was examined, the pH was 2.5. From this, it was confirmed that the emulsion polymerization of the monomer component (Ia) was performed at a pH of about 2.5.

  Next, after maintaining the contents of the flask at 80 ° C. for 60 minutes, 140 parts of deionized water, 48 parts of a 25% aqueous solution of an emulsifier [trade name: ADEKA SORB SR-10, manufactured by ADEKA Corporation], and methyl methacrylate A dropping pre-emulsion obtained by mixing 160 parts, a monomer component (Ib) consisting of 2-ethylhexyl acrylate 230 parts and acrylic acid 10 parts was prepared, and the obtained dropping pre-emulsion was mixed for 80 minutes. , The emulsion polymerization of the monomer component (Ib) was carried out. Thereafter, when the pH of the contents of the flask was examined in the same manner as described above, the pH was 2.7.

  Next, the content of the flask was maintained at 70 ° C. for 10 minutes, and then the pH of the content of the flask was adjusted to 8.1 by adding 25% aqueous ammonia into the flask.

  After maintaining the contents of the flask at 70 ° C. for 60 minutes, 158 parts of deionized water, 54 parts of a 25% aqueous solution of an emulsifier (trade name: ADEKA SORB SR-10, manufactured by ADEKA Corporation), 100 parts of methyl methacrylate, A monomer component (II) comprising 180 parts of 2-ethylhexyl acrylate, 150 parts of cyclohexyl methacrylate, 10 parts of 2-hydroxyethyl methacrylate and 10 parts of 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine is mixed. The resulting pre-emulsion for dropping was prepared, and the obtained pre-emulsion for dropping was uniformly dropped in the flask over 90 minutes. After completion of the dropping, the emulsion polymerization of the monomer component (II) was completed by maintaining the contents of the flask at 70 ° C. for 60 minutes. Upon examining the pH of the contents of the flask, the pH was found to be 8.7.

  Next, 5.0 parts of 25% aqueous ammonia was added into the flask, and the obtained reaction solution was cooled to 40 ° C. and filtered through a 100-mesh wire net to obtain an aqueous resin dispersion. The pH of the obtained aqueous resin dispersion was 9.3.

  The content of nonvolatile components in the aqueous resin dispersion obtained above is 49.8%, the content of the acid group-containing monomer (acrylic acid) in the monomer component (Ia) is 0%, The content of the acid group-containing monomer (acrylic acid) in the monomer component (Ib) is 2.5%, and the monomer composed of the monomer component (Ia) and the monomer component (Ib) The content of the acid group-containing monomer (acrylic acid) in the component (I) is 1.8%, and the content of the acid group-containing monomer (acrylic acid) in all the monomer components is 1.0%. The glass transition temperature of the entire polymer constituting the emulsion particles contained in the aqueous resin dispersion is 2 ° C., the average particle diameter of the emulsion particles is 150 nm, and the aqueous resin dispersion at 25 ° C. Was 1500 mPa · s.

Next, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate [manufactured by JNC Co., Ltd., product number: CS-12] was added to 100 parts of the aqueous resin dispersion obtained above as a film forming aid. ], And stirred with a homodisper at a rotation speed of 1500 min ^{-1 for} 10 minutes, and then 30 parts of the white paste obtained in Preparation Example 1 and black paste [trade name: SK, manufactured by SK Chemical Co., Ltd.] Aqueous color (black)] 7 parts and an antifoaming agent [manufactured by San Nopco Co., Ltd., trade name: Nopco 8034L] 0.5 part were added, and a Krebs unit viscometer (manufactured by Brookfield, product number: KU-1) was added. Thickener [ADEKA Corporation, trade name: ADEKANOL UH-420] and [Nippon Shokubai Co., Ltd., trade name: ACRYSET WR-, so that the viscosity when measured at 25 ° C. becomes 80 KU. 503 About 1: added 1 ratio by stirring for 30 minutes in this state to obtain a water-based paint.

Example 5
527 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, 263 parts of deionized water, 90 parts of a 25% aqueous solution of an emulsifier [ADEKA Corporation, trade name: Adecariasorb SR-10], 100 parts of cyclohexyl methacrylate, 285 parts of methyl methacrylate, 250 parts of 2-ethylhexyl acrylate , 110 parts of styrene and 5 parts of acrylic acid to prepare a pre-emulsion for dropping, and about 74 parts of the pre-emulsion for dropping were added to the flask, and then gently added. The temperature was raised to 70 ° C. while blowing nitrogen gas, and 60 parts of a 5% aqueous solution of ammonium persulfate was added to start the polymerization reaction. Thereafter, the rest of the pre-emulsion for dropping was uniformly dropped into the flask over 130 minutes, and the content of the flask was maintained at 70 ° C. for 60 minutes, thereby completing the emulsion polymerization of the monomer component (I). When the pH of the contents of the flask was examined, the pH was 2.6. This confirmed that the emulsion polymerization of the monomer component (I) was performed at a pH of about 2.6.

  Next, the content of the flask was maintained at 70 ° C. for 10 minutes, and then the pH of the content of the flask was adjusted to 6.8 by adding 25% aqueous ammonia into the flask.

  After maintaining the contents of the flask at 70 ° C. for 60 minutes, 87 parts of deionized water, 30 parts of a 25% aqueous solution of an emulsifier [trade name: Adecariasorb SR-10, manufactured by ADEKA Corporation], 100 parts of cyclohexyl methacrylate, A dropping pre-emulsion obtained by mixing 140 parts of butyl acrylate and a monomer component (II) consisting of 10 parts of γ-methacryloyloxypropyltrimethoxysilane was prepared. The mixture was dropped uniformly into the flask over a period of minutes. Thereafter, when the pH of the contents of the flask was examined in the same manner as described above, the pH was 6.9.

  Next, the content of the flask was maintained at 70 ° C. for 60 minutes, 3.6 parts of 25% aqueous ammonia was added to the flask, and the obtained reaction solution was cooled to 40 ° C. An aqueous resin dispersion was obtained by filtration through a 100-mesh wire net. The pH of the resulting aqueous resin dispersion was 8.5.

  The content of nonvolatile components in the aqueous resin dispersion obtained above was 49.7%, and the content of the acid group-containing monomer (acrylic acid) in the monomer component (I) was 0.67%. Yes, the content of the acid group-containing monomer (acrylic acid) in all the monomer components is 0.5%, and the glass of the whole polymer constituting the emulsion particles contained in the aqueous resin dispersion liquid The transition temperature was 10 ° C., the average particle size of the emulsion particles was 200 nm, and the viscosity of the aqueous resin dispersion at 25 ° C. was 500 mPa · s.

Example 6
780 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, 280 parts of deionized water, 90 parts of a 25% aqueous solution of an emulsifier [ADEKA Corporation, trade name: Adecariasorb SR-10], 150 parts of cyclohexyl methacrylate, 285 parts of methyl methacrylate, 250 parts of 2-ethylhexyl acrylate , 70 parts of styrene and 35 parts of acrylic acid were added to prepare a pre-emulsion for dropping, and about 74 parts of the pre-emulsion for dropping was added to the flask, and then slowly added. The temperature was raised to 70 ° C. while blowing nitrogen gas, and 60 parts of a 5% aqueous solution of ammonium persulfate was added to start the polymerization reaction. Thereafter, the rest of the pre-emulsion for dropping was uniformly dropped into the flask over 140 minutes, and the pH of the contents of the flask was examined. As a result, the pH was 2.1. From this, it was confirmed that the emulsion polymerization of the monomer component (I) was performed at a pH of about 2.1.

  Next, the content of the flask was maintained at 70 ° C. for 10 minutes, and then the pH of the content of the flask was adjusted to 8.4 by adding 25% aqueous ammonia into the flask.

  Next, the mixture was maintained at 70 ° C. for 60 minutes, and subsequently, 70 parts of deionized water, 30 parts of a 25% aqueous solution of an emulsifier [ADEKA Corporation, trade name: Adecaria Sorb SR-10], 70 parts of cyclohexyl methacrylate, and butyl acrylate A dropping pre-emulsion obtained by mixing 130 parts and a monomer component (II) consisting of 10 parts of γ-methacryloyloxypropyltrimethoxysilane was uniformly dropped into the flask over 40 minutes. After completion of the dropping, the emulsion polymerization of the monomer component (II) was completed by maintaining the contents of the flask at 70 ° C. for 60 minutes. When the pH of the contents of the flask was checked, the pH was 8.5.

  Next, 18 parts of 25% aqueous ammonia was added into the flask, and the obtained reaction solution was cooled to 40 ° C. and filtered through a 100-mesh wire net to obtain an aqueous resin dispersion. The pH of the obtained aqueous resin dispersion was 9.5.

  The content of nonvolatile components in the aqueous resin dispersion obtained above was 44.0%, and the content of the acid group-containing monomer (acrylic acid) in the monomer component (I) was 4.4%. The content of the acid group-containing monomer (acrylic acid) in all the monomer components is 3.5%, and the glass of the entire polymer constituting the emulsion particles contained in the aqueous resin dispersion liquid The transition temperature was 11 ° C, the average particle size of the emulsion particles was 200 nm, and the viscosity of the aqueous resin dispersion at 25 ° C was 2700 mPa · s.

Next, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate [manufactured by JNC Co., Ltd., product number: CS-12] was added to 100 parts of the aqueous resin dispersion obtained above as a film forming aid. ], And stirred with a homodisper at a rotation speed of 1500 min ^{-1 for} 10 minutes, and then 30 parts of the white paste obtained in Preparation Example 1 and black paste [trade name: SK, manufactured by SK Chemical Co., Ltd.] Aqueous color (black)] 7 parts and an antifoaming agent [manufactured by San Nopco Co., Ltd., trade name: Nopco 8034L] 0.5 part were added, and a Krebs unit viscometer (manufactured by Brookfield, product number: KU-1) was added. Thickener [ADEKA Corporation, trade name: ADEKANOL UH-420] and [Nippon Shokubai Co., Ltd., trade name: ACRYSET WR-, so that the viscosity when measured at 25 ° C. becomes 80 KU. 503 About 1: added 1 ratio by stirring for 30 minutes in this state to obtain a water-based paint.

Example 7
527 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. 140 parts of deionized water and 48 parts of a 25% aqueous solution of an emulsifier [ADEKA Corporation, trade name: Adecaria Sorb SR-10], 240 parts of methyl methacrylate, 148 parts of 2-ethylhexyl acrylate and 12 parts of acrylic acid in a dropping funnel. To prepare a dropping pre-emulsion, and about 74 parts of the dropping pre-emulsion was added to the flask, and the temperature was raised to 70 ° C. while gently blowing nitrogen gas. After warming, 60 parts of a 5% aqueous solution of ammonium persulfate was added to initiate the polymerization reaction. Thereafter, the rest of the pre-emulsion for dropping was uniformly dropped into the flask over 70 minutes, and the content of the flask was maintained at 70 ° C. for 60 minutes, thereby completing the emulsion polymerization of the monomer component (I). When the pH of the contents of the flask was examined, the pH was 2.8. This confirmed that the emulsion polymerization of the monomer component (I) was performed at a pH of about 2.8.

  Next, the content of the flask was maintained at 70 ° C. for 10 minutes, and then the pH of the content of the flask was adjusted to 7.8 by adding 25% aqueous ammonia into the flask.

  After maintaining the contents of the flask at 70 ° C. for 60 minutes, 210 parts of deionized water, 72 parts of a 25% aqueous solution of an emulsifier [trade name: ADEKA SORB SR-10, manufactured by ADEKA Corporation], 363 parts of methyl methacrylate and A pre-emulsion for dropping obtained by mixing with the monomer component (II) consisting of 237 parts of 2-ethylhexyl acrylate was prepared, and the obtained pre-emulsion for dropping was uniformly dropped in the flask over 110 minutes. . After completion of the dropping, the emulsion polymerization of the monomer component (II) was completed by maintaining the contents of the flask at 70 ° C. for 60 minutes. When the pH of the contents of the flask was checked, the pH was 7.9.

  Next, 6.3 parts of 25% ammonia water was added into the flask, and the obtained reaction solution was cooled to 40 ° C. and filtered through a 100-mesh wire net to obtain an aqueous resin dispersion. The pH of the resulting aqueous resin dispersion was 8.8.

  The nonvolatile content in the aqueous resin dispersion obtained above was 49.8%, the content of the acid group-containing monomer (acrylic acid) in the monomer component (I) was 3%, The content of the acid group-containing monomer (acrylic acid) in all the monomer components was 1.2%, and the glass transition temperature of the entire polymer constituting the emulsion particles contained in the aqueous resin dispersion was Was 11 ° C., the average particle size of the emulsion particles was 180 nm, and the viscosity of the aqueous resin dispersion at 25 ° C. was 1000 mPa · s.

Next, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate [manufactured by JNC Co., Ltd., product number: CS-12] was added to 100 parts of the aqueous resin dispersion obtained above as a film forming aid. ], And stirred with a homodisper at a rotation speed of 1500 min ^{-1 for} 10 minutes, and then 30 parts of the white paste obtained in Preparation Example 1 and black paste [trade name: SK, manufactured by SK Chemical Co., Ltd.] Aqueous color (black)] 7 parts and an antifoaming agent [manufactured by San Nopco Co., Ltd., trade name: Nopco 8034L] 0.5 part were added, and a Krebs unit viscometer (manufactured by Brookfield, product number: KU-1) was added. Thickener [ADEKA Corporation, trade name: ADEKANOL UH-420] and [Nippon Shokubai Co., Ltd., trade name: ACRYSET WR-, so that the viscosity when measured at 25 ° C. becomes 80 KU. 503 About 1: added 1 ratio by stirring for 30 minutes in this state to obtain a water-based paint.

Comparative Example 1
527 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. 87 parts of deionized water, 30 parts of a 25% aqueous solution of an emulsifier [Adekariasorb SR-10], 50 parts of cyclohexyl methacrylate, 75 parts of 2-ethylhexyl acrylate, and 120 parts of methyl methacrylate are added to a dropping funnel. And a monomer component (I) consisting of 5 parts of acrylic acid, to prepare a pre-emulsion for dropping, and about 74 parts of the pre-emulsion for dropping were added to the flask, and nitrogen gas was gently blown therein. The temperature was raised to 70 ° C. while adding 60 parts of a 5% aqueous solution of ammonium persulfate to start the polymerization reaction. After that, the rest of the pre-emulsion for dropping was uniformly dropped into the flask over a period of 40 minutes, and then the pH of the contents of the flask was examined. As a result, the pH was 2.7. This confirmed that the emulsion polymerization of the monomer component (I) was performed at a pH of about 2.7.

  Next, the content of the flask was maintained at 70 ° C. for 10 minutes, and then the pH of the content of the flask was adjusted to 7.8 by adding 25% aqueous ammonia into the flask.

  After maintaining the contents of the flask at 70 ° C. for 60 minutes, 263 parts of deionized water, 90 parts of a 25% aqueous solution of an emulsifier [trade name: ADEKA AREASORB SR-10], 400 parts of methyl methacrylate, The dropping pre-emulsion obtained by mixing the monomer component (II) consisting of 350 parts of 2-ethylhexyl acrylate was uniformly dropped into the flask over 140 minutes. After completion of the dropwise addition, the emulsion polymerization was terminated by maintaining the contents of the flask at 70 ° C. for 60 minutes. When the pH of the contents of the flask was checked, the pH was 7.8.

  Next, the content of the flask was cooled to 40 ° C., 2.5 parts of 25% aqueous ammonia was added to the flask, and the mixture was filtered through a 100-mesh wire net to obtain an aqueous resin dispersion. The pH of the resulting aqueous resin dispersion was 9.1.

  The content of nonvolatile components in the aqueous resin dispersion obtained above was 49.7%, and the content of the acid group-containing monomer (acrylic acid) in the monomer component (I) was 2.0%. Yes, the content of the acid group-containing monomer (acrylic acid) in all the monomer components is 0.5%, and the glass of the whole polymer constituting the emulsion particles contained in the aqueous resin dispersion liquid The transition temperature was 3 ° C., the average particle size of the emulsion particles was 170 nm, and the viscosity of the aqueous resin dispersion at 25 ° C. was 700 mPa · s.

Next, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate [manufactured by JNC Co., Ltd., product number: CS-12] was added to 100 parts of the aqueous resin dispersion obtained above as a film forming aid. ], And stirred with a homodisper at a rotation speed of 1500 min ^{-1 for} 10 minutes, and then 30 parts of the white paste obtained in Preparation Example 1 and black paste [trade name: SK, manufactured by SK Chemical Co., Ltd.] Aqueous color (black)] 7 parts and an antifoaming agent [manufactured by San Nopco Co., Ltd., trade name: Nopco 8034L] 0.5 part were added, and a Krebs unit viscometer (manufactured by Brookfield, product number: KU-1) was added. Thickener [ADEKA Corporation, trade name: ADEKANOL UH-420] and [Nippon Shokubai Co., Ltd., trade name: ACRYSET WR-, so that the viscosity when measured at 25 ° C. becomes 80 KU. 503 About 1: added 1 ratio by stirring for 30 minutes in this state to obtain a water-based paint.

Comparative Example 2
527 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, 350 parts of deionized water, 120 parts of a 25% aqueous solution of an emulsifier [ADEKA Corporation, trade name: Adecariasorb SR-10], 430 parts of 2-ethylhexyl acrylate, 265 parts of methyl methacrylate, 300 parts of styrene and A pre-emulsion for dropping was prepared by adding a monomer component (I) consisting of 5 parts of methacrylic acid. About 74 parts of the pre-emulsion was added to the flask, and the temperature was raised to 70 ° C. while gently blowing nitrogen gas. After warming, 60 parts of a 5% aqueous solution of ammonium persulfate was added to initiate the polymerization reaction. Thereafter, the remainder of the pre-emulsion for dropping was uniformly dropped into the flask over 180 minutes, and the content of the flask was maintained at 70 ° C. for 60 minutes, thereby completing the emulsion polymerization of the monomer component (I). When the pH of the contents of the flask was examined, the pH was 2.8. This confirmed that the emulsion polymerization of the monomer component (I) was performed at a pH of about 2.8.

  Next, the content of the flask was cooled to 40 ° C., 3.8 parts of 25% aqueous ammonia was added to the flask, and the mixture was filtered through a 100-mesh wire net to disperse the aqueous resin having a pH of 9.2. A liquid was obtained.

  The content of nonvolatile components in the aqueous resin dispersion obtained above was 49.6%, and the content of the acid group-containing monomer (acrylic acid) in the monomer component (I) was 0.5%. Yes, the content of the acid group-containing monomer (acrylic acid) in all the monomer components is 0.5%, and the glass of the whole polymer constituting the emulsion particles contained in the aqueous resin dispersion liquid The transition temperature was 2 ° C., the average particle size of the emulsion particles was 160 nm, and the viscosity of the aqueous resin dispersion at 25 ° C. was 1100 mPa · s.

Comparative Example 3
527 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. 140 parts of deionized water, 48 parts of a 25% aqueous solution of an emulsifier [ADEKA Corporation, trade name: Adecariasorb SR-10], 245 parts of methyl methacrylate, 152 parts of 2-ethylhexyl acrylate and 3 parts of acrylic acid in a dropping funnel. To prepare a dropping pre-emulsion, and about 74 parts of the dropping pre-emulsion was added to the flask, and the temperature was raised to 70 ° C. while gently blowing nitrogen gas. After warming, 60 parts of a 5% aqueous solution of ammonium persulfate was added to initiate the polymerization reaction. Thereafter, the rest of the pre-emulsion for dropping was uniformly dropped into the flask over 70 minutes, and the content of the flask was maintained at 70 ° C. for 60 minutes, thereby completing the emulsion polymerization of the monomer component (I). When the pH of the contents of the flask was examined, the pH was 2.8. This confirmed that the emulsion polymerization of the monomer component (I) was performed at a pH of about 2.8.

  Next, the content of the flask was maintained at 70 ° C. for 10 minutes, and then the pH of the content of the flask was adjusted to 7.8 by adding 25% aqueous ammonia into the flask.

  After maintaining the contents of the flask at 70 ° C. for 60 minutes, 210 parts of deionized water, 72 parts of a 25% aqueous solution of an emulsifier (trade name: ADEKA SORB SR-10, manufactured by ADEKA Corporation), 350 parts of methyl methacrylate, The dropping pre-emulsion obtained by mixing 237 parts of 2-ethylhexyl acrylate and 13 parts of 4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine with a monomer component (II) was used. The prepared pre-emulsion for dropping was prepared and uniformly dropped into the flask over 110 minutes. After completion of the dropping, the emulsion polymerization of the monomer component (II) was completed by maintaining the contents of the flask at 70 ° C. for 60 minutes. When the pH of the contents of the flask was checked, the pH was 8.6.

  Next, the content of the flask was cooled to 40 ° C., 1.6 parts of 25% aqueous ammonia was added into the flask, and the mixture was filtered through a 100-mesh wire net to obtain an aqueous resin dispersion. The pH of the resulting aqueous resin dispersion was 9.0.

  The non-volatile content in the aqueous resin dispersion obtained above was 50.1%, and the content of the acid group-containing monomer (acrylic acid) in the monomer component (I) was 0.75%. Yes, the content of the acid group-containing monomer (acrylic acid) in all the monomer components is 0.3%, and the glass of the entire polymer constituting the emulsion particles contained in the aqueous resin dispersion liquid The transition temperature was 10 ° C., the average particle size of the emulsion particles was 180 nm, and the viscosity of the aqueous resin dispersion at 25 ° C. was 350 mPa · s.

Next, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate [manufactured by JNC Co., Ltd., product number: CS-12] was added to 100 parts of the aqueous resin dispersion obtained above as a film forming aid. ], And stirred with a homodisper at a rotation speed of 1500 min ^{-1 for} 10 minutes, and then 30 parts of the white paste obtained in Preparation Example 1 and black paste [trade name: SK, manufactured by SK Chemical Co., Ltd.] Aqueous color (black)] 7 parts and an antifoaming agent [manufactured by San Nopco Co., Ltd., trade name: Nopco 8034L] 0.5 part were added, and a Krebs unit viscometer (manufactured by Brookfield, product number: KU-1) was added. Thickener [ADEKA Corporation, trade name: ADEKANOL UH-420] and [Nippon Shokubai Co., Ltd., trade name: ACRYSET WR-, so that the viscosity when measured at 25 ° C. becomes 80 KU. 503 About 1: added 1 ratio by stirring for 30 minutes in this state to obtain a water-based paint.

Comparative Example 4
527 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. 140 parts of deionized water and 48 parts of a 25% aqueous solution of an emulsifier [ADEKA Corporation, trade name: Adecaria Sorb SR-10], 240 parts of methyl methacrylate, 148 parts of 2-ethylhexyl acrylate and 12 parts of acrylic acid in a dropping funnel. To prepare a dropping pre-emulsion, and about 74 parts of the dropping pre-emulsion was added to the flask, and the temperature was raised to 70 ° C. while gently blowing nitrogen gas. After warming, 60 parts of a 5% aqueous solution of ammonium persulfate was added to initiate the polymerization reaction. Thereafter, the rest of the pre-emulsion for dropping was uniformly dropped into the flask over 70 minutes, and the content of the flask was maintained at 70 ° C. for 60 minutes, thereby completing the emulsion polymerization of the monomer component (I). When the pH of the contents of the flask was examined, the pH was 2.8. This confirmed that the emulsion polymerization of the monomer component (I) was performed at a pH of about 2.8.

  Next, the content of the flask was maintained at 70 ° C. for 10 minutes, and then the pH of the content of the flask was adjusted to 7.7 by adding 25% aqueous ammonia into the flask.

  After maintaining the contents of the flask at 70 ° C. for 60 minutes, 210 parts of deionized water, 72 parts of a 25% aqueous solution of an emulsifier [trade name: ADEKA SORB SR-10, manufactured by ADEKA Corporation], 358 parts of methyl methacrylate, A pre-emulsion for dropping obtained by mixing 237 parts of 2-ethylhexyl acrylate and 5 parts of 4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine with a monomer component (II) was used. The prepared pre-emulsion for dropping was prepared and uniformly dropped into the flask over 110 minutes. After completion of the dropping, the emulsion polymerization of the monomer component (II) was completed by maintaining the contents of the flask at 70 ° C. for 60 minutes. When the pH of the contents of the flask was examined, the pH was 8.3.

  The content of non-volatile components in the aqueous resin dispersion obtained above is 50.1%, the content of the acid group-containing monomer (acrylic acid) in the monomer component (I) is 3%, The content of the acid group-containing monomer (acrylic acid) in all the monomer components was 1.2%, and the glass transition temperature of the entire polymer constituting the emulsion particles contained in the aqueous resin dispersion was Was 11 ° C., the average particle size of the emulsion particles was 190 nm, and the viscosity of the aqueous resin dispersion at 25 ° C. was 400 mPa · s.

Next, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate [manufactured by JNC Co., Ltd., product number: CS-12] was added to 100 parts of the aqueous resin dispersion obtained above as a film forming aid. ], And stirred with a homodisper at a rotation speed of 1500 min ^{-1 for} 10 minutes, and then 30 parts of the white paste obtained in Preparation Example 1 and black paste [trade name: SK, manufactured by SK Chemical Co., Ltd.] Aqueous color (black)] 7 parts and an antifoaming agent [manufactured by San Nopco Co., Ltd., trade name: Nopco 8034L] 0.5 part were added, and a Krebs unit viscometer (manufactured by Brookfield, product number: KU-1) was added. Thickener [ADEKA Corporation, trade name: ADEKANOL UH-420] and [Nippon Shokubai Co., Ltd., trade name: ACRYSET WR-, so that the viscosity when measured at 25 ° C. becomes 80 KU. 503 About 1: added 1 ratio by stirring for 30 minutes in this state to obtain a water-based paint.

Comparative Example 5
527 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. 140 parts of deionized water and 48 parts of a 25% aqueous solution of an emulsifier [ADEKA Corporation, trade name: Adecaria Sorb SR-10], 240 parts of methyl methacrylate, 148 parts of 2-ethylhexyl acrylate and 12 parts of acrylic acid in a dropping funnel. To prepare a dropping pre-emulsion, and about 74 parts of the dropping pre-emulsion was added to the flask, and the temperature was raised to 70 ° C. while gently blowing nitrogen gas. After warming, 60 parts of a 5% aqueous solution of ammonium persulfate was added to initiate the polymerization reaction. Thereafter, the rest of the pre-emulsion for dropping was uniformly dropped into the flask over 70 minutes, and the content of the flask was maintained at 70 ° C. for 60 minutes, thereby completing the emulsion polymerization of the monomer component (I). When the pH of the contents of the flask was examined, the pH was 2.8. This confirmed that the emulsion polymerization of the monomer component (I) was performed at a pH of about 2.8.

  After maintaining the contents of the flask at 70 ° C. for 60 minutes, 210 parts of deionized water, 72 parts of a 25% aqueous solution of an emulsifier (trade name: ADEKA SORB SR-10, manufactured by ADEKA Corporation), 350 parts of methyl methacrylate, A dropping pre-emulsion obtained by mixing 237 parts of 2-ethylhexyl acrylate and 13 parts of 4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine with a monomer component (II) was prepared. When the prepared pre-emulsion for dropping was prepared and uniformly dropped into the flask over 110 minutes, aggregation of emulsion particles occurred, so that an aqueous resin dispersion could not be obtained.

Comparative Example 6
670 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. 40 parts of deionized water and 40 parts of a 25% aqueous solution of an emulsifier [Aqualon HS-10] manufactured by Daiichi Kogyo Seiyaku Co., Ltd., and an emulsifier [Daiichi Kogyo Seiyaku Co., Ltd., trade name] : Aqualon RN-20] and a monomer component (I) consisting of 212 parts of methyl methacrylate, 50 parts of 2-ethylhexyl acrylate and 8 parts of acrylic acid, thereby adding a pre-emulsion for dropping. Was prepared, and about 74 parts of the pre-emulsion for dropping was added to the flask, the temperature was raised to 80 ° C. while gently blowing nitrogen gas, and 60 parts of a 5% aqueous potassium persulfate solution was added to initiate a polymerization reaction. . Then, the remainder of the pre-emulsion for dropping was uniformly dropped into the flask over 50 minutes. Thereafter, when the pH of the contents of the flask was examined in the same manner as described above, the pH was 2.6.

  After completion of the dropwise addition, the content of the flask was maintained at 80 ° C. for 30 minutes, and the pH of the content of the flask was adjusted to 7.2 by adding 25% aqueous ammonia into the flask.

  Next, after maintaining the contents of the flask at 80 ° C. for 60 minutes, 250 parts of deionized water and 20 parts of a 25% aqueous solution of an emulsifier (trade name: Aqualon HS-10, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) were added. 20 parts of a 25% aqueous solution of an emulsifier [manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon RN-20], 390 parts of 2-ethylhexyl acrylate, 275 parts of methyl methacrylate, 50 parts of cyclohexyl methacrylate, γ-methacryloyloxypropyl A dropping pre-emulsion obtained by mixing 10 parts of trimethoxysilane and a monomer component (II) consisting of 5 parts of 4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine was used. The prepared pre-emulsion for dropping was prepared and uniformly dropped into the flask over 130 minutes.

  After the completion of the dropwise addition, the emulsion polymerization of the monomer component (II) was completed by maintaining the contents of the flask at 80 ° C. for 60 minutes. When the pH of the contents of the flask was measured, the pH was 8.0. After adding 3.2 parts of 25% aqueous ammonia to the flask, the obtained reaction solution is cooled to 40 ° C., and filtered through a 100-mesh wire net to obtain an aqueous resin having a pH of 8.6. A dispersion was obtained.

  The content of nonvolatile components in the aqueous resin dispersion obtained above was 48.0%, and the content of the acid group-containing monomer (acrylic acid) in the monomer component (I) was 3.0%. The content of the acid group-containing monomer (acrylic acid) in all the monomer components is 0.8%, and the glass of the whole polymer constituting the emulsion particles contained in the aqueous resin dispersion liquid The transition temperature was 0 ° C., the average particle size of the emulsion particles was 170 nm, and the viscosity of the aqueous resin dispersion at 25 ° C. was 1100 mPa · s.

Next, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate [manufactured by JNC Co., Ltd., product number: CS-12] was added to 100 parts of the aqueous resin dispersion obtained above as a film forming aid. ], And stirred with a homodisper at a rotation speed of 1500 min ^{-1 for} 10 minutes, and then 30 parts of the white paste obtained in Preparation Example 1 and black paste [trade name: SK, manufactured by SK Chemical Co., Ltd.] Aqueous color (black)] 7 parts and an antifoaming agent [manufactured by San Nopco Co., Ltd., trade name: Nopco 8034L] 0.5 part were added, and a Krebs unit viscometer (manufactured by Brookfield, product number: KU-1) was added. Thickener [ADEKA Corporation, trade name: ADEKANOL UH-420] and [Nippon Shokubai Co., Ltd., trade name: ACRYSET WR-, so that the viscosity when measured at 25 ° C. becomes 80 KU. 503 About 1: added 1 ratio by stirring for 30 minutes in this state to obtain a water-based paint.

  The following physical properties were examined using the water-based paints obtained in each of the examples or comparative examples. Table 1 shows the results. In addition, a thing with evaluation of x in physical property is also judged as rejection.

(1) Pattern retention A slate plate (manufactured by Nippon Test Panel Co., Ltd., length: 70 mm, width: 150 mm, thickness: 6 mm) is air-sprayed with a sealer [manufactured by SK Chemical Co., Ltd., trade name: EX sealer]. At 150 g / m ² , and dried at 23 ° C. for 1 week.

Next, an aqueous solution of the water-based paint is prepared by mixing the water-based paint and water at a ratio of 10 parts of water per 100 parts of the water-based paint, and this aqueous solution is mixed with a sag tester (5 mils of 4 mil, 8 mil, 10 mil, 15 mil, 15 mil and 20 mil). Immediately after applying the film thickness of the step at a time, the interval between each coating film: 5 mm), the film is vertically erected at an angle of 90 °, and dried at 23 ° C. for one day as it is. The appearance of the coating film was visually observed, and the pattern retention was evaluated based on the following evaluation criteria.
〔Evaluation criteria〕
◎: The coating film is clearly separated at a film thickness of 10 mil or more.
：: The coating film is slightly blurred at a film thickness of 10 mil or more, but is separated.
X: The coating film is not separated at all with a film thickness of less than 10 mil.

(2) Thickness The water-based paint and water were mixed at a ratio of 10 parts by weight of water to 100 parts by weight of the water-based paint obtained above to prepare a mixture.

Next, a sealer (trade name: EX Sealer, manufactured by SK Chemical Co., Ltd., trade name: EX sealer) is applied to a flexible board (length: 150 mm, width: 150 mm, thickness: 4 mm) by air spray at a coating amount of 150 g / m ^2. And dried at 80 ° C. for 10 minutes in a hot air dryer. Immediately after the drying, the mixture obtained above on the coating film formed on the surface of the flexible board is subjected to a sag tester so that the wet thickness of the coating film becomes a predetermined coating film thickness of 100 to 500 μm. A test plate was prepared by coating, and the obtained test plate was immediately dried with a hot air drier at a wind speed of 1 m / s for 30 minutes. The test plate was taken out of the hot air drier and shrinkage wrinkles were formed on the coating film. Was determined as the critical film thickness, and the critical film thickness was evaluated based on the following evaluation criteria.
〔Evaluation criteria〕
◎: Limit film thickness of 375 μm or more ：: Limit film thickness of 250 μm to 375 μm ×: Limit film thickness of less than 250 μm

(3) Weather resistance A slate plate [manufactured by Japan Test Panel Co., Ltd., length: 70 mm, width: 150 mm, thickness: 6 mm] is sealed with an air sprayer with a sealer [manufactured by SK Chemical Co., Ltd., trade name: EX sealer]. The coating was uniformly applied at a coating amount of 150 g / m ² and dried at 23 ° C. for one week.

Next, the aqueous paint obtained above was applied with a 10 mil applicator and dried in an atmosphere at 23 ° C. for one week, and the side and back surfaces of the slate plate to which the aqueous paint was applied were sealed with aluminum tape. The 60 ° specular gloss of the surface to which the water-based paint was applied was measured with a gloss meter (manufactured by Nippon Denshoku Industries Co., Ltd., product number: VG2000), and a weather resistance test was conducted for 500 hours under the following conditions. Measure the gloss of the painted surface of the slate plate with a gloss meter, and calculate the formula:
[Gloss retention (%)]
= [[Gloss after weather resistance test] / [gloss before weather resistance test]] x 100
And weather resistance was evaluated based on the following evaluation criteria.

(Test conditions for weather resistance test)
・ Testing machine: Metal Weather [manufactured by Daipla Wintes Co., Ltd., product number: KU-R4]
・ Irradiation: Irradiation for 4 hours in an atmosphere at a temperature of 65 ° C. and a relative humidity of 50% (irradiation intensity: 80 mW / cm ² )
・ Humidity: 4 hours in an atmosphere of a temperature of 35 ° C. and a relative humidity of 98% ・ Shower: 30 seconds each before and after wetting

〔Evaluation criteria〕
◎: Gloss retention rate of 80% or more ：: Gloss retention rate of 70% or more and less than 80% △: Gloss retention rate of 60% or more and less than 70% X: Gloss retention rate of less than 60%

(4) Discoloration resistance The water-based paint obtained above was applied to a glass plate (manufactured by Nippon Test Panel Co., Ltd., length: 70 mm, width: 150 mm, thickness: 6 mm, the same applies hereinafter) with a 6 mil applicator, and 23 ° C. After drying for 1 day, the surface on which the water-based paint is applied is subjected to L ^* 0, a ^* 0 and L ^* 0 using a color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd., product number: spectral color difference meter SE-2000). b ^* 0 was measured.

L ^* represents lightness, a ^* represents a value obtained by subtracting the reflection intensity of the green wavelength from the reflection intensity of the red wavelength, and b ^* represents the reflection intensity of the blue wavelength subtracted from the reflection intensity of the yellow wavelength. Value.

Next, after storing the water-based paint in a thermostat at 50 ° C. for 30 days, it was coated and dried on a glass plate under the same conditions, and L ^* 1, a ^* 1, and b ^* 1 were measured.

From the measured values of L ^* 0, a ^* 0 and b ^* 0 after measurement and before storage, and L ^* 1, a ^* 1 and b ^* 1 after storage, the formula:
ΔE ^* (color difference)
^{= [(L * 0-L} * 1) 2 + (a * 0-a * 1) 2 + (b * 0-b * 1) 2] 1/2
ΔE ^* was obtained based on the following, and the discoloration resistance was evaluated based on the following evaluation criteria.
〔Evaluation criteria〕
◎: ΔE ^* is less than 0.5 ○: ΔE ^* is 0.5 or more and less than 0.7 Δ: ΔE ^* is 0.7 or more and less than 1.0 x: ΔE ^* is 1.0 or more

(5) Comprehensive Evaluation In each property, ◎ was 25 points, ○ was 15 points, Δ was 5 points, and × was 0 point, and the total evaluation of each property was performed. Table 1 shows the results.

  From the results shown in Table 1, all of the aqueous resin dispersions obtained in each of the examples were excellent in pattern retention, thick film properties, weather resistance and discoloration resistance as compared with the comparative examples. You can see that there is.

  The method for producing an aqueous resin dispersion and the aqueous resin dispersion are useful for applications such as paints and coating agents.

Claims (5)

Producing an aqueous resin dispersion containing emulsion particles by subjecting a monomer component (I) containing an acid group-containing monomer having an ethylenically unsaturated double bond and a monomer component (II) to multistage emulsion polymerization. The amount of the monomer component (I) is adjusted to 35 to 80% by mass of all the monomer components used in the multi-stage emulsion polymerization to adjust the monomer component (I) to a pH of 1. When emulsion polymerization is carried out in the conditions of (1) to (5), a monomer component (Ia) composed of an alkyl (meth) acrylate and an acid group-containing monomer having an ethylenically unsaturated double bond are used as the monomer component (I). Using a monomer component (Ib) containing an ethylenically unsaturated double bond-containing monomer containing a monomer, and emulsion-polymerizing the monomer component (Ia), the monomer component (Ib) After the emulsion polymerization, the pH of the resin emulsion (I) obtained by the emulsion polymerization is adjusted to 6 to 10, and then the ethylenically unsaturated double bond is formed. The monomer component (II) containing the monomer is added to the resin emulsion (I) in an amount of 20 to 65% by mass of all the monomer components used in the multi-stage emulsion polymerization and emulsion polymerization is performed. A method for producing an aqueous resin dispersion, wherein the pH of a resin emulsion (II) obtained by emulsion polymerization is increased by 0.5 to 2.   The aqueous resin dispersion according to claim 1, wherein the ethylenically unsaturated double bond-containing monomer used in the monomer component (II) contains a hydroxyl group-containing (meth) acrylate and a (meth) acryloyl group-containing piperidine compound. Manufacturing method. A method for producing an aqueous resin dispersion containing emulsion particles by subjecting monomer component (I) and monomer component (II) to multi-stage emulsion polymerization, wherein monomer component (I) is ethylenically unsaturated. A monomer component comprising an acid group-containing monomer having a double bond , methyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, wherein the monomer component (II) is methyl (meth) acrylate, A monomer component comprising an ethylhexyl (meth) acrylate and a (meth) acryloyl group-containing piperidine compound, and the amount of the monomer component (I) is 35 to 80 mass of the total monomer component used in the multistage emulsion polymerization. %, And the monomer component (I) is emulsion-polymerized at a pH of 1 to 5; the pH of the resin emulsion (I) obtained by the emulsion polymerization is adjusted to 6 to 10; Used for emulsion polymerization A monomer component (II) in an amount of 20 to 65% by mass of the monomer component is added to the resin emulsion (I), the monomer component (II) is emulsion-polymerized, and the resin obtained by the emulsion polymerization is added. A method for producing an aqueous resin dispersion, wherein the pH of the emulsion (II) is increased by 0.5 to 2. An aqueous resin dispersion containing emulsion particles by subjecting a monomer component (I) containing an acid group-containing monomer having an ethylenically unsaturated double bond and a monomer component (II) to multistage emulsion polymerization. The method for producing, wherein the monomer component (I) is a monomer component containing an acid group-containing monomer having an ethylenically unsaturated double bond, an alkyl (meth) acrylate and a styrene monomer. The monomer component (II) is a monomer component containing an alkyl (meth) acrylate and a silane group-containing monomer having an ethylenically unsaturated double bond , and the amount of the monomer component (I) Is adjusted to be 35 to 80% by mass of all the monomer components used in the multistage emulsion polymerization, and the monomer component (I) is emulsion-polymerized at a pH of 1 to 5 to obtain the emulsion component obtained by the emulsion polymerization. After adjusting the pH of the resin emulsion (I) to 6 to 10, it was used for multistage emulsion polymerization. The monomer component (II) is added to the resin emulsion (I) in an amount of 20 to 65% by mass of the total monomer components to be obtained, and the monomer component (II) is emulsion-polymerized to obtain the emulsion component. A method for producing an aqueous resin dispersion, wherein the pH of the obtained resin emulsion (II) is increased by 0.5 to 2. The monomer component (I) is an acid group-containing monomer having an ethylenically unsaturated double bond , cyclohexyl (meth) acrylate, methyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and a styrene-based monomer A monomer component containing cyclohexyl (meth) acrylate, butyl (meth) acrylate and a silane group-containing monomer having an ethylenically unsaturated double bond. The method for producing an aqueous resin dispersion according to claim 4, which is a monomer component.