JP2018172678A - Resin emulsion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin emulsion which forms a coated film that contains a triazine-based ultraviolet absorber and is excellent in ultraviolet tone retention and transparency.SOLUTION: A resin emulsion contains a triazine-based ultraviolet absorber, where a monomer component containing cycloalkyl(meth)acrylate having a cycloalkyl group having 3 to 12 carbon atoms is used as a resin raw material of the resin emulsion, and a content of the cycloalkyl(meth)acrylate having the cycloalkyl group having 3 to 12 carbon atoms in the monomer component is 15-70 mass%.SELECTED DRAWING: None

Description

  The present invention relates to a resin emulsion. More specifically, the present invention is referred to as a top coat that is coated on the surface of, for example, ceramic building materials, automobiles, buildings, civil engineering structures, and the like, especially the exterior of buildings and ceramic building materials. The present invention relates to a top coating, a resin emulsion that can be suitably used for the top coating, and a method for producing the resin emulsion.

  Water-based paint that has good storage stability and can form a coating film with low gloss, water repellency, water resistance, weather resistance, gloss retention and stain resistance even when a small amount of silicone resin water dispersion is used. As a composition, a (meth) acrylic polymer emulsion (A) obtained by polymerizing a (meth) acrylic monomer containing 2-15% by mass of a hydroxyl group-containing polymerizable monomer, an aqueous silicone resin dispersion (B) and the high HLB surfactant (C) whose HLB is 16-20, and the said high HLB surfactant (C) is 0 with respect to 100 mass parts of (meth) acrylic-type polymer emulsion (A). An aqueous coating composition containing 2 to 2 parts by mass has been proposed (see, for example, claim 1 of Patent Document 1).

  In the water-based coating composition, a triazine ultraviolet absorber is used for the purpose of improving weather resistance (see paragraph [0054] of Patent Document 1). However, since the triazine-based ultraviolet absorber is inferior in dispersibility in the resin emulsion, the coating film formed using the resin emulsion has a disadvantage that it is not only inferior in transparency but also inferior in ultraviolet color tone retention. (See Comparative Example 1 in this specification).

JP 2011-213941 A

  The present invention has been made in view of the prior art, and is a resin emulsion containing a triazine-based ultraviolet absorber, which forms a coating film excellent in ultraviolet color tone retention and transparency, and its production It is an object of the present invention to provide a method and a top coating composition containing the resin emulsion.

The present invention
(1) A resin emulsion containing a triazine-based ultraviolet absorber, wherein a monomer component containing a cycloalkyl (meth) acrylate having a cycloalkyl group having 3 to 12 carbon atoms is used as a resin raw material of the resin emulsion. A resin emulsion, wherein the content of the cycloalkyl (meth) acrylate having a cycloalkyl group having 3 to 12 carbon atoms in the monomer component is 15 to 70% by mass,
(2) The resin emulsion according to (1), wherein the resin emulsion is a resin emulsion containing emulsion particles containing a triazine-based ultraviolet absorber.
(3) The resin emulsion according to (2) above, wherein a triazine-based ultraviolet absorber is contained in the outermost layer of the emulsion particles,
(4) A topcoat comprising the resin emulsion according to any one of (1) to (3),
(5) The topcoat paint according to (4), wherein the topcoat paint is a clear paint used for the outermost layer of the article to be coated,
(6) A method for producing a resin emulsion containing a triazine-based ultraviolet absorber, wherein when the monomer component is polymerized in the presence of the triazine-based ultraviolet absorber, the number of carbon atoms is 3 as the monomer component. The content rate of the cycloalkyl (meth) acrylate which has a C3-C12 cycloalkyl group in the said monomer component using the monomer component containing the cycloalkyl (meth) acrylate which has -12 cycloalkyl groups And (7) The method for producing a resin emulsion according to (6) above, wherein the monomer component contains a triazine-based ultraviolet absorber. About.

  According to the present invention, a resin emulsion containing a triazine-based ultraviolet absorber, which forms a coating film excellent in ultraviolet color tone retention and transparency, a method for producing the same, and a topcoat containing the resin emulsion A paint is provided.

  As described above, the resin emulsion of the present invention contains a triazine-based ultraviolet absorber, and contains a cycloalkyl (meth) acrylate having a cycloalkyl group having 3 to 12 carbon atoms as a resin raw material of the resin emulsion. The body component is used, and the content of the cycloalkyl (meth) acrylate having a cycloalkyl group having 3 to 12 carbon atoms in the monomer component is 15 to 70% by mass.

  Although the resin emulsion of the present invention contains a triazine-based ultraviolet absorber, a monomer component containing a cycloalkyl (meth) acrylate having a cycloalkyl group having 3 to 12 carbon atoms is used as a resin raw material for the resin emulsion. Since the content of the cycloalkyl (meth) acrylate having a cycloalkyl group having 3 to 12 carbon atoms in the monomer component is 15 to 70% by mass, the coating film excellent in ultraviolet color tone retention and transparency Form.

  In addition, in this invention, the ultraviolet color tone retainability of a coating film means the property which suppresses the color tone of a coating film changing for a long time by irradiation of the ultraviolet-ray contained in a sunlight ray. Therefore, that the ultraviolet color tone retention property of a coating film is excellent means that a change in the color tone of the coating film is small when the coating film is irradiated with ultraviolet rays of sunlight for a long time.

  In the present invention, among various ultraviolet absorbers, a triazine-based ultraviolet absorber is used in a resin emulsion, and a cycloalkyl having a C 3-12 cycloalkyl group as a resin raw material of the resin emulsion ( A monomer component containing a (meth) acrylate is used, and the content of the cycloalkyl (meth) acrylate having a cycloalkyl group having 3 to 12 carbon atoms in the monomer component is 15% by mass or more. There are features. Thus, in this invention, while using the triazine type ultraviolet absorber for the resin emulsion, it contains the cycloalkyl (meth) acrylate which has a C3-C12 cycloalkyl group as a resin raw material of the said resin emulsion. The monomer component is used, and the content of the cycloalkyl (meth) acrylate having a cycloalkyl group having 3 to 12 carbon atoms in the monomer component is 15% by mass or more. In addition to the above-described structure, not only is excellent in ultraviolet color tone retention, but also an extremely remarkable effect that cannot be expected from the prior art to form a coating film excellent in transparency is exhibited.

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

  The resin emulsion of the present invention is, for example, a method of polymerizing a monomer component in the presence of a triazine-based ultraviolet absorber, emulsion polymerization of the monomer component, and mixing the obtained resin emulsion with a triazine-based ultraviolet absorber. It can be obtained by the method to do. Among these methods, the monomer component is added in the presence of a triazine-based ultraviolet absorber from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency, and excellent in water resistance and freeze-thaw repeated stability. A polymerization method is preferred.

  Examples of a method for polymerizing a monomer component in the presence of a triazine-based ultraviolet absorber include, for example, a method for polymerizing a monomer component containing a triazine-based ultraviolet absorber, and an aqueous medium containing a triazine-based ultraviolet absorber. Although the method of emulsion-polymerizing a monomer component in presence is mentioned, this invention is not limited only to this illustration. Among these methods, a monomer component containing a triazine-based ultraviolet absorber is polymerized from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency, and excellent in water resistance and freeze-thaw repeated stability. The method is preferred.

  Hereinafter, as a method of polymerizing the monomer component in the presence of the triazine-based ultraviolet absorber, when the monomer component is polymerized in the presence of the triazine-based ultraviolet absorber, the monomer component has 3 to 3 carbon atoms. Using a monomer component containing a cycloalkyl (meth) acrylate having 12 cycloalkyl groups, the content of the cycloalkyl (meth) acrylate having a cycloalkyl group having 3 to 12 carbon atoms in the monomer component A method for preparing a resin emulsion by adjusting to 15 to 70% by mass will be described.

  Examples of the triazine-based ultraviolet absorber include 2- [4-[(2-hydroxy-3-dodecyloxypropyl) oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl)- 1,3,5-triazine, 2- [4-[(2-hydroxy-3-tridecyloxypropyl) oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1 , 3,5-triazine, 2- [4-[(2-hydroxy-3- (2′-ethyl) hexyl) oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine, 2,4-bis (2-hydroxy-4-butyloxyphenyl) -6- (2,4-bis-butyloxyphenyl) -1,3,5-triazine, hydroxyphenyl Triazine, -(2-hydroxy-4- [1-octyloxycarbonylethoxy] phenyl) -4,6-bis (4-phenylphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy Examples include hydroxyphenyl triazine-based ultraviolet absorbers such as -4-hexyloxy-3-methylphenyl) -1,3,5-triazine, but the present invention is not limited to such examples. These triazine-based ultraviolet absorbers may be used alone or in combination of two or more. Among these triazine-based ultraviolet absorbers, 2- [4-[(2-hydroxy) is preferred from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency, and excellent in water resistance and freeze-thaw repeated stability. -3-dodecyloxypropyl) oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine, 2- [4-[(2-hydroxy-3) Hydroxyphenyl triazine-based UV absorbers such as -tridecyloxypropyl) oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine are preferred.

  Triazine-based ultraviolet absorbers can be easily obtained commercially. Examples thereof include, for example, BASF Japan Ltd., trade name: TINUVIN (registered trademark, hereinafter the same) 400 [2- [4-[(2-hydroxy-3-dodecyloxypropyl) oxy] -2-hydroxy Phenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine and 2- [4-[(2-hydroxy-3-tridecyloxypropyl) oxy] -2-hydroxyphenyl ] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine], TINUVIN405 [2- [4-[(2-hydroxy-3- (2′-ethyl) hexyl] ) Oxy] -2-hydroxyphenyl] -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine], TINUVIN 460 [2,4-bis (2-hydroxy-4-buty) Oxyphenyl) -6- (2,4-bis-butyloxyphenyl) -1,3,5-triazine], TINUVIN477 [hydroxyphenyltriazine], TINUVIN479 [2- (2-hydroxy-4- [1-octyloxy] Carbonylethoxy] phenyl) -4,6-bis (4-phenylphenyl) -1,3,5-triazine], manufactured by ADEKA Corporation, trade name: ADK STAB (registered trademark) F70 [2,4,6-Tris Examples include hydroxyphenyl triazine-based ultraviolet absorbers such as (2-hydroxy-4-hexyloxy-3-methylphenyl) -1,3,5-triazine], but the present invention is limited to such examples only. It is not a thing. These triazine-based ultraviolet absorbers may be used alone or in combination of two or more.

  The amount of the triazine-based ultraviolet absorber per 100 parts by mass of the monomer component used as the resin raw material of the resin emulsion of the present invention is preferably 0.1 mass from the viewpoint of forming a coating film excellent in ultraviolet color tone retention. Part or more, more preferably 0.2 part by weight or more, more preferably 0.3 part by weight or more, still more preferably 0.5 part by weight or more, and excellent in transparency, water resistance and freeze-thaw repeat stability. From the viewpoint of forming a coating film, it is preferably 5 parts by mass or less, more preferably 4.5 parts by mass or less, further preferably 4 parts by mass or less, and still more preferably 3.5 parts by mass or less.

  Examples of the cycloalkyl (meth) acrylate having a cycloalkyl group having 3 to 12 carbon atoms include cyclopropyl (meth) acrylate, cyclobutyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) ) Acrylate and the like, but the present invention is not limited to such examples. These cycloalkyl (meth) acrylates having a cycloalkyl group having 3 to 12 carbon atoms may be used alone or in combination of two or more. Among these cycloalkyl (meth) acrylates having a cycloalkyl group having 3 to 12 carbon atoms, the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency, excellent in water resistance and freeze-thaw repeat stability. Therefore, a cycloalkyl (meth) acrylate having a cycloalkyl group having 3 to 10 carbon atoms is preferable, a cycloalkyl (meth) acrylate having a cycloalkyl group having 4 to 8 carbon atoms is more preferable, and a cyclohexyl (meth) acrylate is further included. preferable.

  The content of the cycloalkyl (meth) acrylate having a cycloalkyl group having 3 to 12 carbon atoms in the monomer component is excellent in UV color tone retention and transparency, and excellent in water resistance and freeze-thaw repeat stability. From the viewpoint of forming, it is 15% by mass or more, preferably 20% by mass or more, more preferably 25% by mass or more, still more preferably 30% by mass or more, and still more preferably 35% by mass or more. From the viewpoint of forming an excellent coating film, it is 70% by mass or less, preferably 65% by mass or less, more preferably 60% by mass or less, still more preferably 55% by mass or less, still more preferably 50% by mass or less, even more Preferably it is 45 mass% or less.

  As the monomer component, a monomer other than the cycloalkyl (meth) acrylate having a cycloalkyl group having 3 to 12 carbon atoms (hereinafter simply referred to as “other monomer”) can be used.

  Examples of other monomers include alkyl (meth) acrylates, aromatic monomers, hydroxyl group-containing (meth) acrylates, carboxyl group-containing monomers, silane group-containing monomers, and nitrogen atom-containing monomers. , Oxo group-containing monomers, fluorine atom-containing monomers, epoxy group-containing monomers, UV-stable monomers, UV-absorbing monomers, etc., but the present invention is limited to such examples only. Is not to be done. These other monomers may be used alone or in combination of two or more. Among these other monomers, from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency, and excellent in water resistance and freeze-thaw repeated stability, alkyl (meth) acrylates, aromatic single monomers are used. Preferred are a monomer, a hydroxyl group-containing (meth) acrylate, a carboxyl group-containing monomer, a silane group-containing monomer, and a UV-stable monomer, and an alkyl (meth) acrylate, a hydroxyl group-containing (meth) acrylate, a carboxyl group-containing monomer More preferred are monomers, UV-stable monomers and silane group-containing monomers, and alkyl (meth) acrylates are even more preferred. In other words, the monomer component used as the resin raw material is preferably a monomer component containing the cycloalkyl (meth) acrylate having a C 3-12 cycloalkyl group and an alkyl (meth) acrylate.

  Examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, and sec-butyl (meth). Alkyl (meth) acrylates having 1 to 18 carbon atoms in the alkyl group such as acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, tridecyl (meth) acrylate, n-lauryl (meth) acrylate, etc. Although mentioned, this invention is not limited only to this illustration. These alkyl (meth) acrylates may be used alone or in combination of two or more. Among these alkyl (meth) acrylates, the alkyl group has 1 to 8 carbon atoms from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency, water resistance and freeze-thaw repeat stability. Certain alkyl (meth) acrylates are preferred, with methyl (meth) acrylate, n-butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate being more preferred.

  The content of the alkyl (meth) acrylate in the monomer component is preferably 30% by mass or more from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency, excellent in water resistance and freeze-thaw repeat stability. More preferably 35% by mass or more, still more preferably 40% by mass or more, further preferably 45% by mass or more, still more preferably 50% by mass or more, and particularly preferably 55% by mass or more. From the viewpoint of forming a coating film excellent in transparency, water resistance and freeze-thaw repeat stability, it is preferably 85% by mass or less, more preferably 80% by mass or less, still more preferably 75% by mass or less, and further preferably. Is 70% by mass or less, more preferably 65% by mass or less.

  Examples of the aromatic monomer include styrene, α-methylstyrene, p-methylstyrene, tert-methylstyrene, chlorostyrene, aralkyl (meth) acrylate, vinyltoluene, and the like. It is not limited to illustration only. Examples of the aralkyl (meth) acrylate include aralkyl having 7 to 18 carbon atoms such as benzyl (meth) acrylate, phenylethyl (meth) acrylate, methylbenzyl (meth) acrylate, naphthylmethyl (meth) acrylate and the like. Although (meth) acrylate etc. are mentioned, this invention is not limited only to this illustration. These aromatic monomers may be used alone or in combination of two or more. Among these aromatic monomers, styrene is preferable from the viewpoint of forming a coating film excellent in transparency, water resistance, and freeze-thaw repeated stability.

  The content of the aromatic monomer in the monomer component is 0% by mass or more, preferably 1% by mass or more, from the viewpoint of forming a coating film excellent in transparency, water resistance and freeze-thaw repeat stability. More preferably 2% by mass or more, further preferably 3% by mass or more, and preferably 10% by mass or less, more preferably 8% from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and freeze-thaw repeatability. It is 7% by mass or less, more preferably 7% by mass or less.

  Examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4-hydroxy Examples include hydroxyl group-containing (meth) acrylates having 1 to 18 carbon atoms in ester groups such as butyl (meth) acrylate and glycerin mono (meth) acrylate, but the present invention is not limited to such examples. . These hydroxyl group-containing (meth) acrylates may be used alone or in combination of two or more. Among these hydroxyl group-containing (meth) acrylates, 2-hydroxyethyl (meth) acrylate and glycerin mono (from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency and excellent in freeze-thaw repeated stability. (Meth) acrylate is preferred, and 2-hydroxyethyl methacrylate is more preferred.

  The content of the hydroxyl group-containing (meth) acrylate in the monomer component is 0% by mass or more, preferably 0 from the viewpoint of forming a coating film having excellent ultraviolet color tone retention and transparency and excellent freeze-thaw repeat stability. .1% by mass or more, more preferably 0.3% by mass or more, and further preferably 0.5% by mass or more, excellent in UV color tone retention and transparency, excellent in water resistance and freeze-thaw repeat stability. From the viewpoint of forming a film, it is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 3% by mass or less.

  Examples of the carboxyl group-containing monomer include (meth) acrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, maleic anhydride, and other carboxyl group-containing aliphatic monomers. The invention is not limited to such examples. These carboxyl group-containing monomers may be used alone or in combination of two or more. Among these carboxyl group-containing monomers, (meth) acrylic acid is preferable from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency, and excellent in water resistance and freeze-thaw repeated stability.

  The content of the carboxyl group-containing monomer in the monomer component is 0% by mass or more, preferably 0.1% by mass or more, from the viewpoint of forming a coating film having excellent transparency and freeze-thaw repeat stability. Preferably it is 0.2% by mass or more, more preferably 0.3% by mass or more, and preferably 5% by mass or less, more preferably from the viewpoint of forming a coating film excellent in water resistance and freeze-thaw repeated stability. 3% by mass or less, more preferably 2% by mass or less.

  Examples of the silane group-containing monomer include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (methoxyethoxy) silane, γ- (meth) acryloyloxypropyltrimethoxysilane, 2-styrylethyltrimethoxysilane, vinyltri Examples include chlorosilane, γ- (meth) acryloyloxypropylhydroxysilane, and γ- (meth) acryloyloxypropylmethylhydroxysilane, but the present invention is not limited to such examples. These silane group-containing monomers may be used alone or in combination of two or more. Among these silane group-containing monomers, γ- (meth) acryloyloxypropyltrimethoxysilane is preferred from the viewpoint of forming a coating film excellent in ultraviolet color tone retention, water resistance and freeze-thaw repeat stability, γ-Methacryloyloxypropyltrimethoxysilane is more preferable.

  The content of the silane group-containing monomer in the monomer component is 0% by mass or more, preferably 0.5% by mass or more, more preferably from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and water resistance. Is 1% by mass or more, more preferably 1.5% by mass or more, and preferably 5% by mass or less from the viewpoint of forming a coating film excellent in ultraviolet color tone retention, water resistance and freeze-thaw repeat stability. Preferably it is 4 mass% or less, More preferably, it is 3 mass% or less.

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

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

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

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

  Examples of UV-stable monomers include 4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine, 4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine. 4- (meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloyl-1-methoxy-2,2,6,6-tetramethylpiperidine, 4-cyano- 4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-croto Noylamino-2,2,6,6-tetramethylpiperidine, 4- (meth) acryloylamino-1,2,2,6,6-pentamethylpiperidine, 4-sia -4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4-cyano- Examples include 4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine and the like. However, the present invention is not limited to such examples. These ultraviolet stable monomers may be used alone or in combination of two or more. Among these UV-stable monomers, 4- (meth) acryloyloxy-2,2,6,6 is used from the viewpoint of forming a coating film excellent in UV color tone retention, water resistance and freeze-thaw repeat stability. 6-tetramethylpiperidine and 4- (meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine are preferred, 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine, and 4 -Methacryloyloxy-1,2,2,6,6-pentamethylpiperidine is more preferred.

  The content of the UV-stable monomer in the monomer component is 0% by mass or more, preferably 0.1% by mass or more, from the viewpoint of forming a coating film excellent in UV color tone retention and freeze-thaw repeatability. More preferably, it is 0.3% by mass or more, more preferably 0.5% by mass or more, and preferably 5% by mass from the viewpoint of forming a coating film excellent in transparency, water resistance and freeze-thaw repeat stability. Hereinafter, it is more preferably 3% by mass or less, and further preferably 2% by mass or less.

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

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

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

  The content of other monomers in the monomer component is preferably 30% by mass or more from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency, and excellent in water resistance and freeze-thaw repeat stability. More preferably 35% by mass or more, still more preferably 40% by mass or more, further preferably 45% by mass or more, still more preferably 50% by mass or more, and particularly preferably 55% by mass or more. From the viewpoint of forming a coating film excellent in transparency, water resistance and freeze-thaw repeat stability, it is preferably 85% by mass or less, more preferably 80% by mass or less, still more preferably 75% by mass or less, and further preferably. Is 70% by mass or less, more preferably 65% by mass or less.

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

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

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

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

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

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

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

  Further, as the emulsifier, an emulsifier having a polymerizable group, that is, a so-called reactive emulsifier is preferable from the viewpoint of forming a coating film excellent in ultraviolet color tone retention, water resistance and freeze-thaw repeat stability, and from the viewpoint of environmental protection. Therefore, non-nonylphenyl type emulsifiers are preferred.

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

  The amount of the emulsifier per 100 parts by mass of the monomer component is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, further preferably 2 parts by mass or more, from the viewpoint of improving the polymerization stability. From the viewpoint of forming a coating film excellent in ultraviolet color tone retention, water resistance and freeze-thaw repeat stability, it is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and further preferably 5 parts by mass or less.

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

  The amount of the polymerization initiator per 100 parts by mass of the monomer component is preferably 0.01 parts by mass or more, more preferably 0 from the viewpoint of increasing the polymerization rate and reducing the residual amount of the unreacted monomer component. 0.03 parts by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less from the viewpoint of forming a coating film excellent in ultraviolet color tone retention, water resistance and freeze-thaw repeat stability.

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

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

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

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

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

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

  By emulsion polymerization of the monomer component (hereinafter referred to as “the monomer component”) as described above, a resin emulsion containing emulsion particles can be obtained.

  The polymer constituting the emulsion particles may have a crosslinked structure. The weight average molecular weight of the polymer is preferably 100,000 or more, more preferably 300,000 or more, and further preferably 550,000, from the viewpoint of forming a coating film excellent in ultraviolet color tone retention, water resistance and freeze-thaw repeat stability. Above, especially preferably 600,000 or more. The upper limit of the weight average molecular weight of the polymer is not particularly limited because it is difficult to measure the weight average molecular weight when it has a cross-linked structure, but when it does not have a cross-linked structure, the film-forming property is improved. From the viewpoint, it is preferably 5 million or less.

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

  The emulsion particles contained in the resin emulsion of the present invention may have a single resin layer prepared by one-stage emulsion polymerization, or may have a plurality of resin layers prepared by multi-stage emulsion polymerization. It may be. Among these emulsion particles, it is preferable to have a plurality of resin layers from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency, and excellent in water resistance and freeze-thaw repeat stability. When the emulsion particles have a plurality of resin layers, the boundary between the resin layers is not necessarily clear, and adjacent resin layers may be mixed with each other.

  The number of the resin layers constituting the emulsion particles is preferably 1 to 5 layers, more preferably from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency, and excellent in water resistance and freeze-thaw repeat stability. 1-3 layers, more preferably 2 and 3 layers.

  In addition, among the emulsion particles having a plurality of resin layers, each of the emulsion particles constituting the emulsion particles from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency, and excellent in water resistance and freeze-thaw repeat stability. Of the resin layers, emulsion particles having a resin layer having the highest glass transition temperature in a layer inside the outermost layer are preferred.

  Emulsion particles having a single resin layer can be prepared by emulsion polymerization of the monomer component. Moreover, the emulsion particle | grains which have a some resin layer can be prepared by carrying out multistage emulsion polymerization of a monomer component with the polymerization method and polymerization conditions similar to the case where the said monomer component is emulsion-polymerized.

  When the emulsion particles have a plurality of resin layers, the monomer component forming each layer is excellent in ultraviolet color tone retention and transparency, from the viewpoint of forming a coating film excellent in water resistance and freeze-thaw repeat stability, It is preferable that each contains a triazine-based ultraviolet absorber.

  In the present invention, it is preferable that a triazine ultraviolet absorber is contained in the outermost layer (surface layer) of the emulsion particles from the viewpoint of further improving the ultraviolet color tone retention and transparency. When the emulsion particles are composed of a single layer (one layer) resin layer, the outermost layer is the single layer resin layer. When the emulsion particles are composed of two resin layers, an inner layer and an outer layer, the outermost layer is the outer layer. When the emulsion particles are composed of three resin layers, an inner layer, an intermediate layer, and an outer layer, the outermost layer is the outer resin layer. When the emulsion particles have at least two resin layers, the resin layer other than the outermost layer may also contain a triazine ultraviolet absorber.

  The content of the triazine-based ultraviolet absorber in the monomer component used as a resin raw material for the resin constituting the outermost layer is preferably 0.1 from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency. % By mass or more, more preferably 0.2% by mass or more, still more preferably 0.3% by mass or more, and still more preferably 0.5% by mass or more. Ultraviolet color tone retention transparency, water resistance, and repeated freeze-thawing From the viewpoint of forming a coating film excellent in stability, it is preferably 5% by mass or less, more preferably 4.5% by mass or less, further preferably 4% by mass or less, and still more preferably 3.5% by mass or less. .

  Emulsion particles having two resin layers, an inner layer and an outer layer, emulsion-polymerize the monomer component that forms the inner layer, and emulsion-polymerize the monomer component that forms the outer layer in the presence of the obtained emulsion particles. Can be prepared. In this case, the monomer component is a monomer component that forms an inner layer and an outer layer from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency, and excellent in water resistance and freeze-thaw repeated stability. It is preferably used. The mass ratio between the resin layer constituting the inner layer and the resin layer constituting the outer layer (resin layer constituting the inner layer / resin layer constituting the outer layer) is excellent in UV color tone retention and transparency. From the viewpoint of forming a coating film excellent in water resistance and freeze-thaw repeat stability, it is preferably 10/90 or more, more preferably 20/80 or more, further preferably 30/70 or more, and still more preferably 40 / From the viewpoint of improving the film-forming property, adhesion and blocking resistance, it is preferably 80/20 or less, more preferably 70/30 or less, and further preferably 60/40 or less.

  The emulsion particles having the three resin layers of the inner layer, the intermediate layer, and the outer layer are obtained by emulsion polymerization of the monomer component that forms the inner layer, and the monomer component that forms the intermediate layer in the presence of the obtained emulsion particles. Can be prepared by emulsion polymerization of the monomer component forming the outer layer in the presence of the obtained emulsion particles. In this case, the monomer component is a single amount that forms an inner layer, an intermediate layer, and an outer layer from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency, and excellent in water resistance and freeze-thaw repeated stability. It is preferably used as a body component. In addition, the content of the resin layer constituting the inner layer is 10 to 40% by mass from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency, and excellent in water resistance and freeze-thaw repeat stability. The content of the resin layer constituting the intermediate layer is preferably 20 to 60% by mass, and the content of the resin layer constituting the outer layer is preferably 20 to 60% by mass.

  In the emulsion particles having a single resin layer, the glass transition temperature of the resin layer is preferably from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency, and excellent in water resistance and freeze-thaw repeat stability. Is −10 ° C. or higher, more preferably −5 ° C. or higher, further preferably 0 ° C. or higher, preferably 40 ° C. or lower, more preferably 30 ° C. or lower, and still more preferably 20 ° C. or lower.

  In emulsion particles having two resin layers, an inner layer and an outer layer, the inner layer is constituted from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency, and excellent in water resistance and freeze-thaw repeat stability. The glass transition temperature of the resin layer is preferably −20 to 120 ° C., more preferably −10 to 110 ° C., and the glass transition temperature of the resin layer constituting the outer layer is preferably −40 to 70 ° C., More preferably, it is -30-60 degreeC.

  In the emulsion particles having three resin layers, an inner layer, an intermediate layer, and an outer layer, the inner layer is formed from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency, and excellent in water resistance and freeze-thaw repeat stability. The glass transition temperature of the constituting resin layer is preferably 50 to 150 ° C., more preferably 80 to 100 ° C., and the glass transition temperature of the resin layer constituting the intermediate layer is preferably −80 to 0 The glass transition temperature of the resin layer constituting the outer layer is preferably 0 to 50 ° C., more preferably 10 to 40 ° C.

  Moreover, the glass transition temperature of the whole emulsion particles having a plurality of resin layers is preferably −10 from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency, and excellent in water resistance and freeze-thaw repeat stability. ° C or higher, more preferably -5 ° C or higher, still more preferably 0 ° C or higher, preferably 50 ° C or lower, more preferably 40 ° C or lower, still more preferably 30 ° C or lower.

  The glass transition temperature of the resin layer constituting the emulsion particles can be easily adjusted by adjusting the type and amount of the monomer used for the monomer component.

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

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

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

  The glass transition temperature of the polymer is, for example, 105 ° C. for a homopolymer of methyl methacrylate, 100 ° C. for a homopolymer of styrene, 83 ° C. for a homopolymer of cyclohexyl methacrylate, and −70 for a homopolymer of 2-ethylhexyl acrylate. ° C, -56 ° C for n-butyl acrylate homopolymer, 20 ° C for n-butyl methacrylate homopolymer, 55 ° C for 2-hydroxyethyl methacrylate homopolymer, 95 ° C for acrylic acid homopolymer, 130 ° C. for homopolymer of methacrylic acid, 130 ° C. for homopolymer of 4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine, 70 for homopolymer of γ-methacryloyloxypropyltrimethoxysilane ° C.

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

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

  From the viewpoint of improving the mechanical stability of the emulsion particles themselves, the average particle size of the emulsion particles is preferably 50 nm or more, more preferably 80 nm or more, and is excellent in ultraviolet color tone retention and transparency, water resistance and freeze-thaw. From the viewpoint of forming a coating film excellent in repeated stability, it is preferably 300 nm or less, more preferably 200 nm or less.

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

As the resin emulsion of the present invention, for example,
(1) A resin emulsion containing emulsion particles containing a triazine-based ultraviolet absorber obtained by emulsion polymerization of a monomer component containing a triazine-based ultraviolet absorber.
(2) Examples of the present invention include a resin emulsion obtained by mixing a resin emulsion containing emulsion particles obtained by emulsion polymerization of the monomer component and a triazine-based ultraviolet absorber. It is not limited to illustration only. Among these resin emulsions, a resin emulsion containing emulsion particles containing a triazine-based ultraviolet absorber is preferred from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency.

  From the viewpoint of improving productivity, the total content of the emulsion particles and the triazine-based UV absorber in the resin emulsion of the present invention is preferably 30% by mass or more, more preferably 40% by mass or more, and handling properties. From the viewpoint of improving the ratio, it is preferably 60% by mass or less, more preferably 50% by mass or less.

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

  The minimum film-forming temperature of the resin emulsion of the present invention is preferably 5 ° C. or less from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency, and excellent in water resistance and freeze-thaw repeat stability. Preferably it is 0 degrees C or less. The minimum film-forming temperature of the resin emulsion can be adjusted, for example, by adjusting the glass transition temperature of the entire emulsion particles or the glass transition temperature of the outermost resin layer.

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

  The resin emulsion of the present invention obtained as described above may contain, for example, a crosslinking agent if necessary. Examples of the crosslinking agent include melamine crosslinking agent, oxazoline crosslinking agent, acrylamide crosslinking agent, polyamide crosslinking agent, epoxy crosslinking agent, isocyanate crosslinking agent, aziridine crosslinking agent, titanate crosslinking agent, urea crosslinking. Agents, alkyl alcoholated urea-based crosslinking agents, hydrazine compounds, carbodiimide compounds, zirconium compounds, zinc compounds, titanium compounds, aluminum compounds, and the like, but the present invention is limited to such examples only. It is not a thing. These crosslinking agents may be used alone or in combination of two or more. The amount of the crosslinking agent is preferably set as appropriate according to the type of the crosslinking agent. Among the crosslinking agents, an oxazoline-based crosslinking agent and a hydrazine-based crosslinking agent are preferable from the viewpoint of forming a coating film excellent in ultraviolet color tone retention and transparency, and excellent in water resistance and freeze-thaw repeated stability.

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

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

  The resin emulsion of the present invention is excellent in ultraviolet color tone retention and transparency, and forms a coating film excellent in water resistance and freeze-thaw repeated stability. For example, it is applied to the surface of a building exterior, a ceramic building material, etc. It can be suitably used for a top coating material called a top coat.

  The top coating composition of the present invention contains the resin emulsion of the present invention. The total content of the emulsion particles and the non-volatile content of the triazine-based UV absorber in the solid content contained in the top coat of the present invention is excellent in UV color tone retention and transparency, and excellent in water resistance and freeze-thaw repeat stability. From the viewpoint of forming a film, it is preferably 50% by mass or more, more preferably 60% by mass or more, and further preferably 70% by mass or more, and the upper limit is 100% by mass.

  Since the top coating composition of the present invention is excellent in transparency, it can be suitably used as a clear coating for a top coat for allowing the design of the intermediate coating layer or the top coating layer to be coated to be seen.

  Accordingly, when used as a top coat clear paint, the top coat paint of the present invention preferably contains only the resin emulsion of the present invention, but if necessary, it contains, for example, a pigment, an additive and the like. May be.

  Examples of the pigment include organic pigments and inorganic pigments, and these pigments may be used alone or in combination of two or more.

  Examples of organic pigments include azo pigments, azomethine pigments, methine pigments, anthraquinone pigments, phthalocyanine pigments, perinone pigments, perylene pigments, diketopyrrolopyrrole pigments, thioindigo pigments, iminoisoindoline pigments, iminoisoindolinone pigments, and quinacridone red. And quinacridone pigments such as quinacridone violet, flavanthrone pigment, indanthrone pigment, anthrapyrimidine pigment, carbazole pigment, monoarylide yellow, diarylide yellow, benzoimidazolone yellow, tolyl orange, naphthol orange, quinophthalone pigment, etc. However, the present invention is not limited to such examples. These organic pigments may be used alone or in combination of two or more.

  Examples of inorganic pigments include titanium dioxide, red iron oxide, black iron oxide, iron oxide, chromium oxide green, carbon black, ferric ferrocyanide (Prussian blue), ultramarine, lead chromate, and mica. (Mica), clay, aluminum powder, pigment having a flat shape such as talc, aluminum silicate, and extender pigments such as calcium carbonate, magnesium hydroxide, aluminum hydroxide, barium sulfate, magnesium carbonate, etc. Is not limited to such examples. These inorganic pigments may be used alone or in combination of two or more.

  The solid content of the pigment in the top coating composition of the present invention is 0% by mass or more, but preferably 3% by mass from the viewpoint of increasing the coating film hardness and improving the designability or concealing property of the formed coating film. As mentioned above, More preferably, it is 5 mass% or more, From a viewpoint of improving film forming property, Preferably it is 50 mass% or less, More preferably, it is 40 mass% or less.

The solid content of the pigment in the top coating composition of the present invention has the formula:
[Solid content (mass%) of pigment in top coat]
= [(Solid content of pigment) / (solid content of resin emulsion + solid content of pigment)] × 100
Means the value obtained based on

  Examples of additives include aggregates, leveling agents, antioxidants, polymerization inhibitors, fillers, coupling agents, rust inhibitors, antibacterial agents, metal deactivators, wetting agents, antifoaming agents, and surface active agents. Agent, reinforcing agent, plasticizer, lubricant, antifogging agent, anticorrosive agent, pigment dispersant, flow modifier, peroxide decomposing agent, mold bleaching agent, fluorescent whitening agent, organic flameproofing agent, inorganic flameproofing Agent, anti-dripping agent, melt flow modifier, antistatic agent, anti-algae agent, anti-mold agent, flame retardant, slip agent, metal chelating agent, anti-blocking agent, heat stabilizer, processing stabilizer, dispersant, Examples include thickeners, rheology control agents, foaming agents, anti-aging agents, preservatives, antistatic agents, silane coupling agents, antioxidants, and the like, but the present invention is not limited to such examples. . These additives may be used alone or in combination of two or more.

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

  The total non-volatile content in the top coating composition of the present invention varies depending on the use of the top coating composition of the present invention and cannot be determined unconditionally, but it is usually preferably 10 to 70% by mass.

  The top coating composition of the present invention can be easily prepared, for example, by mixing the resin emulsion of the present invention, and if necessary, a pigment, an additive, water and the like.

  Since the top coating composition of the present invention obtained as described above contains the resin emulsion of the present invention, it forms a coating film excellent in ultraviolet color tone retention and transparency, and excellent in water resistance and freeze-thaw repeated stability. Therefore, for example, it can be suitably used for surface finishing of a base material made of a material such as metal, glass, porcelain, concrete, siding board, or resin. Accordingly, the top coating composition of the present invention can be suitably used as a top coating composition called a top coat that is applied to the surface of an exterior of a building, a ceramic building material, or the like.

  Examples of ceramic building materials include tiles and outer wall materials. Ceramic building materials are obtained by adding inorganic fillers, fibrous materials, etc. to hydraulic glue that is the raw material of inorganic hardened bodies, molding the resulting mixture, curing the resulting molded body, and curing it. can get. As an inorganic building material which comprises the exterior of a building, a flexible board, a calcium silicate board, a gypsum slag perlite board, a piece of wood cement board, a precast concrete board, an ALC board, a gypsum board etc. are mentioned, for example.

  A top coating is usually applied to the surface of such building materials in order to impart a desired design. The top coating composition of the present invention can be suitably used for this top coating composition.

  The top coating composition of the present invention may be applied alone as a single layer, or may be applied by recoating two or more layers. When coating is performed by recoating two or more layers, only a part of the layers may be formed by the top coating composition of the present invention, or all the layers may be formed by the top coating composition of the present invention. For overcoating, for example, a first layer (for example, undercoat layer) coating is applied to an object that has been subjected to primer treatment or sealer treatment, and then dried, and then for the second layer (for example, topcoat layer). Although the method of overcoating and drying a paint is mentioned, this invention is not limited by this method. Examples of the method for applying the top coat of the present invention include a coating method using a brush, a bar coater, an applicator, an air spray, an airless spray, a roll coater, a flow coater, etc., but the present invention is only such examples. It is not limited to.

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

  Moreover, the thickness after drying of the coating film formed using the top coating composition of the present invention is excellent in ultraviolet color tone retention and transparency, and is a viewpoint for forming a coating film excellent in water resistance and freeze-thaw repeated stability. Therefore, it is usually preferable to be about 1 to 100 μm.

The coating amount of the top coating material on the base material varies depending on the type of the base material and cannot be determined unconditionally, but is excellent in UV color tone retention and transparency, and excellent in water resistance and freeze-thaw repeated stability. From the viewpoint of forming a coating film, it is usually preferable that the nonvolatile content is about 10 to ²⁰⁰ g / m ² .

  Among the objects to be coated, there is a multi-layer finish coating material in which a clear layer (transparent layer) is formed on the surface of a formed overcoat layer after repeatedly applying a base coat and a top coat. Since the top coating composition of the present invention is excellent in transparency, it can be suitably used for applications in which the color and design of the top coating film formed by the top coating composition can be recognized from the outside.

  In order to impart a desired design to the surface of the clear layer, after the clear layer is formed, the clear layer is formed until the clear layer is dried, or after the clear layer is dried, for example, aluminum Matte pigments such as flakes, scaly mica and pearl pigments, inorganic particles such as silica particles and talc, organic particles such as polyethylene particles and poly (meth) acrylic particles, etc., if necessary in the clear layer It may be sprayed.

  In addition, in order to impart hydrophilicity or water repellency to the surface of the clear layer, after forming the clear layer, after forming the clear layer until the clear layer is dried, or after drying the clear layer, For example, a dispersion of silica particles such as colloidal silica, a dispersion of aluminum particles such as alumina sol, and photocatalyst particles such as titanium oxide may be dispersed in the clear layer as necessary.

  Also, the outer walls of buildings, roofs, roof tiles, ceramic building materials, etc. are exposed to sunlight, especially ultraviolet rays over a long period of time, exposed to wind and rain, and pollutants in the atmosphere adhere to them. It is important that the color tone and design of the transparent coating itself are not changed by the ultraviolet rays of the sun rays so that the color tone and the design of the transparent coating layer are not changed. Since the resin emulsion of the present invention is used, the top coating composition of the present invention is excellent in ultraviolet color tone retention and transparency, and can be suitably used as a clear coating for a top coat of an object to be coated.

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

Example 1
716 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, 417 parts of deionized water, 120 parts of a 25% aqueous solution of an emulsifier [manufactured by ADEKA, trade name: Adekaria Soap SR-10], 330 parts of methyl methacrylate as a monomer component, 250 parts of cyclohexyl methacrylate, 2 -Triazine UV so that the amount of triazine UV absorber per 200 parts of ethylhexyl acrylate, 200 parts of n-butyl acrylate, 5 parts of acrylic acid and 5 parts of methacrylic acid, and 100 parts of the monomer component is 1 part. A pre-emulsion for dripping containing 10 parts of an absorbent [manufactured by BASF Japan Ltd., trade name: TINUVIN 400] was prepared, of which 154 parts corresponding to 10% of the total amount of the monomer component and the triazine-based ultraviolet absorber. Is added to the flask and gently blown with nitrogen gas. Until the temperature was raised, it was added 5% aqueous solution of ammonium persulfate 10 parts, to initiate polymerization. Thereafter, the remainder of the pre-emulsion for dropping and 30 parts of 5% aqueous ammonium persulfate solution were uniformly dropped into the flask over 240 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 80 ° C. for 60 minutes, and the pH was adjusted to 8 by adding 25% aqueous ammonia to complete the polymerization. After cooling the obtained reaction liquid to room temperature, the resin emulsion was prepared by filtering with a 300 mesh (JIS mesh, the same hereafter) wire mesh. Table 1 shows the composition of the monomer component and triazine-based ultraviolet absorber used as the resin raw material of the obtained resin emulsion.

Example 2
A resin emulsion was prepared in the same manner as in Example 1 except that the monomer components in Example 1 were changed as shown in Table 1. Table 1 shows the composition of the monomer component and triazine-based ultraviolet absorber used as the resin raw material of the obtained resin emulsion.

Example 3
716 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 full funnel, 209 parts of deionized water, 60 parts of a 25% aqueous solution of an emulsifier [manufactured by ADEKA, Inc., trade name: ADEKA rear soap SR-10], 242.5 parts of methyl methacrylate as a monomer component, 210 of cyclohexyl methacrylate Parts, 2-ethylhexyl acrylate 40 parts and methacrylic acid 5 parts, and triazine ultraviolet absorber [BASF Japan Ltd. ), Trade name: TINUVIN 400] A pre-emulsion for first-stage dropping containing 2.5 parts is prepared, of which 77 parts, which is 10% of the total amount of the monomer component and the triazine-based ultraviolet absorber, are flasked. Add to the inside and raise the temperature to 80 ° C while gently blowing nitrogen gas, 5% ammonium persulfate aqueous solution 10 parts was added to initiate polymerization. Thereafter, the remainder of the pre-emulsion for dropping and 15 parts of a 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 120 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 80 ° C. for 60 minutes. Subsequently, 209 parts of deionized water and 60 parts of a 25% aqueous solution of an emulsifier (manufactured by ADEKA, trade name: Adekari Soap SR-10) were used. , 210 parts of cyclohexyl methacrylate, 77.5 parts of 2-ethylhexyl acrylate, 200 parts of n-butyl acrylate and 10 parts of 4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine as a monomer component, and all 2.5 parts of a triazine-based ultraviolet absorber [manufactured by BASF Japan Ltd., trade name: TINUVIN400] was contained so that the amount of the triazine-based ultraviolet absorber per 100 parts of the monomer component was 0.5 parts. Flask uniformly for 120 minutes with pre-emulsion for 2nd drop and 15 parts of 5% ammonium persulfate aqueous solution It was dropped in.

  After completion of the dropwise addition, the contents of the flask were maintained at 80 ° C. for 60 minutes, and the pH was adjusted to 8 by adding 25% aqueous ammonia to complete the polymerization. After cooling the obtained reaction liquid to room temperature, the resin emulsion was prepared by filtering with a 300 mesh metal-mesh. Table 1 shows the composition of the monomer component and triazine-based ultraviolet absorber used as the resin raw material of the obtained resin emulsion.

Examples 4-7
In Example 3, a resin emulsion was prepared in the same manner as in Example 3 except that the monomer component and the triazine-based ultraviolet absorber were changed as shown in Table 1. Table 1 shows the composition of the monomer component and triazine-based ultraviolet absorber used as the resin raw material of the obtained resin emulsion.

Example 8
716 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 lower funnel, 139 parts of deionized water, 40 parts of a 25% aqueous solution of an emulsifier [manufactured by ADEKA, trade name: Adekaria soap SR-10], 180 parts of methyl methacrylate as a monomer component, 140 parts of cyclohexyl methacrylate and 10 parts of methacrylic acid and triazine-based UV absorber [trade name: TINUVIN400, manufactured by BASF Japan Ltd.] so that the amount of the triazine-based UV absorber per 3.1 parts of all monomer components is 3.1 parts. 1 part of the pre-emulsion for dropping is prepared, and 51 parts, which is 10% of the total amount of the monomer component and the triazine-based UV absorber, is added into the flask, and nitrogen gas is gently blown into the flask. While raising the temperature to 80 ° C., 10 parts of 5% ammonium persulfate aqueous solution was added to initiate polymerization. Thereafter, the remainder of the pre-emulsion for dropping and 10 parts of 5% ammonium persulfate aqueous solution were uniformly dropped into the flask over 90 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 80 ° C. for 60 minutes. Subsequently, 139 parts of deionized water and 40 parts of a 25% aqueous solution of an emulsifier [manufactured by ADEKA, trade name: ADEKA rear soap SR-10] The amount of the triazine-based UV absorber per monomer is 83 parts per mole of cyclohexyl methacrylate 83 parts, 227 parts 2-ethylhexyl acrylate and 10 parts γ-methacryloyloxypropyltrimethoxysilane, and 100 parts of all monomer components. A pre-emulsion for second-stage dropping containing 10 parts of a triazine-based UV absorber [manufactured by BASF Japan Ltd., trade name: TINUVIN 400] and 10 parts of a 5% aqueous solution of ammonium persulfate uniformly over 90 minutes. It was dripped in the flask.

  After completion of the dropwise addition, the contents of the flask were maintained at 80 ° C. for 60 minutes. Subsequently, 139 parts of deionized water and 40 parts of a 25% aqueous solution of an emulsifier [manufactured by ADEKA, trade name: ADEKA rear soap SR-10] , 50 parts of methyl methacrylate, 150 parts of cyclohexyl methacrylate, 100 parts of 2-ethylhexyl acrylate, 10 parts of 4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine and γ-methacryloyloxypropyltri 10 parts of methoxysilane and triazine UV absorber [BASF Japan Co., Ltd., trade name: TINUVIN400] 10 so that the amount of triazine UV absorber per 100 parts of all monomer components is 3.1 parts. Pre-emulsion for 3rd stage dripping and 5% ammonium persulfate 10 parts of an aqueous solution was added dropwise to uniformly flask over 90 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 80 ° C. for 60 minutes, and the pH was adjusted to 8 by adding 25% aqueous ammonia to complete the polymerization. After cooling the obtained reaction liquid to room temperature, the resin emulsion was prepared by filtering with a 300 mesh metal-mesh. Table 1 shows the composition of the monomer component and triazine-based ultraviolet absorber used as the resin raw material of the obtained resin emulsion.

Comparative Examples 1-3
A resin emulsion was prepared in the same manner as in Example 1 except that the monomer components and the ultraviolet absorber were changed as shown in Table 2 in Example 1. Table 2 shows the composition of monomer components and ultraviolet absorbers used as resin raw materials for the obtained resin emulsion.

The abbreviations listed in Tables 1 and 2 mean the following.
MMA: methyl methacrylate St: styrene CHMA: cyclohexyl methacrylate 2EHA: 2-ethylhexyl acrylate BA: n-butyl acrylate BMA: n-butyl methacrylate HEMA: 2-hydroxyethyl methacrylate AA: acrylic acid MAA: methacrylic acid HALS: 4-methacryloyloxy -1,2,2,6,6-pentamethylpiperidine TMSMA: γ-methacryloyloxypropyltrimethoxysilane TIN400: triazine ultraviolet absorber [trade name: TINUVIN400, manufactured by BASF Japan Ltd.]
TIN1130: Benzotriazole ultraviolet absorber [manufactured by BASF Japan Ltd., trade name: TINUVIN1130]

Moreover, the term of the following Tables 1-2 means the following.
[Number of layers]
Number of resin layers constituting emulsion particles contained in resin emulsion [amount of cycloalkyl (meth) acrylate]
Content (% by mass) of cycloalkyl (meth) acrylate having a cycloalkyl group having 3 to 12 carbon atoms in all monomer components
[Amount of triazine UV absorber]
Amount of triazine UV absorber per 100 parts of total monomer component (parts)
[Non-volatile content]
Nonvolatile content in resin emulsion (% by mass)
[Tg of layer 1]
Glass transition temperature (° C) of resin layer 1 constituting emulsion particles
[Tg of layer 2]
Glass transition temperature (° C) of resin layer 2 constituting the emulsion particles
[Tg of layer 3]
Glass transition temperature (° C) of resin layer 3 constituting emulsion particles
[Total Tg]
Glass transition temperature of emulsion particles themselves (℃)

  In Table 1, Layers 1 to 3 indicate that the layers were polymerized in that order to form layers. In the monomer component in Table 1, “-” means that the layer is not formed.

Experimental Example Next, 100 parts of the resin emulsion obtained in each example or each comparative example, 20 parts of water, 5 parts of butyl cellosolve [manufactured by Kyowa Hakko Bio Co., Ltd.] and 2,2,4- A mixed solution was obtained by adding 5 parts of trimethyl-1,3-pentanediol monoisobutyrate [manufactured by Chisso Corporation, product number: CS-12]. The obtained mixed solution was added to the flask, stirred with a homodisper at a rotational speed of 1500 min ^{−1 for} 30 minutes, and measured at 25 ° C. using a Craves unit viscometer (Brookfield, product number: KU-1). A thickener [made by Nippon Shokubai Co., Ltd., trade name: Acreset WR-503A] was added to the flask so that the viscosity at the time was 65 KU, and an antifoaming agent [San Nopco Co., Ltd. trade name: SN deformer 777] 0.3 parts was added to the flask and stirred for 30 minutes to prepare a sample for evaluation.

  Using the evaluation paint obtained above, the water resistance, ultraviolet color tone retention, transparency and freeze-thaw repeated stability were examined as physical properties of the resin emulsion based on the following methods. The results are shown in Table 3.

(1) Water resistance The sample for evaluation obtained above is a glass plate [manufactured by Nippon Test Panel Co., Ltd., length: 70 mm, width: 150 mm, thickness: 2 mm] and the thickness of the coating film after drying is 50 μm. It was applied with an applicator and dried at a temperature of 80 ° C. for 2 hours.

Next, 60 ° specular gloss (hereinafter referred to as gloss before immersion in warm water) of the surface on which the sample for evaluation was applied was measured with a gloss meter (manufactured by Nippon Denshoku Industries Co., Ltd., product number: VG2000), and further 50 ° C. After being immersed in warm water for 1 day, it is taken out from the water, and the gloss of the painted surface of the glass plate (hereinafter referred to as gloss after immersion in hot water) is measured with the gloss meter.
Formula: [Gloss retention (%)] = [[Gloss after immersion in warm water] ÷ [Gloss before immersion in warm water]] × 100
The water resistance was evaluated based on the following evaluation criteria.

〔Evaluation criteria〕
A: Gloss retention is 90% or more B: Gloss retention is 75% or more and less than 90% Δ: Gloss retention is 60% or more and less than 75% X: Gloss retention is less than 60%

(2) UV-resistant color tone retention A slate plate (manufactured by Nippon Test Panel Co., Ltd., length: 70 mm, width: 150 mm, thickness: 6 mm) with a sealer (manufactured by SK Kaken Co., Ltd., trade name: EX sealer) A coating film was formed by uniformly applying with an air spray at an application amount of 150 g / m ² and drying in the atmosphere at 23 ° C. for 1 week.

  On the coating film formed as described above, the following colored paint was applied with an applicator so that the thickness of the coating film after drying was 100 μm, dried in the atmosphere at 23 ° C. for 1 week, and further The evaluation sample obtained above was applied on the coating film formed on the surface of the slate plate with an applicator so that the thickness of the coating film after drying was 20 μm, and 1 at 23 ° C. in the air. A test plate was obtained by drying for a week.

[Colored paint]
10 parts of water and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate as a film-forming aid in an acrylic resin emulsion [manufactured by Nippon Shokubai Co., Ltd., trade name: Acryset EMN-210E] [Chisso Co., Ltd., product number: CS-12] 10 parts was added and stirred with a homodisper at a rotational speed of 1500 min ^{-1 for} 30 minutes, followed by 30 parts of white paste and an antifoaming agent [San Nopco Co., Ltd. Product name: SN deformer 777] 0.5 parts is added, and the viscosity is 70 KU when measured at 25 ° C. using a Craves unit viscometer (Brookfield, product number: KU-1). A thickener [ADEKA Co., Ltd., trade name: Adecanol UH-420] was added, followed by an aqueous color paste [manufactured by SK Kaken Co., Ltd., trade name: SK aqueous color (A Rust, was added Oka and color mixture of blue)] 5 parts, by stirring for 30 minutes in this state, and the colored coating material was prepared.

[White paste]
210 parts of deionized water, 60 parts of dispersant [manufactured by Kao Corporation, trade name: Demol EP], 50 parts of dispersant [manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name: DISCOAT N-14], wetting agent [Kao Co., Ltd., product 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 A white paste was prepared by dispersing the part with a homodisper at a rotational speed of 3000 min ^{−1 for} 60 minutes.

The side surface and the back surface of the test plate obtained above were sealed with aluminum tape, and the color difference (L ₀ , a ₀ , b ₀ ) of the coating surface of the test plate was measured using a color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd., Product name: spectroscopic color difference meter SE-2000]. Next, after performing an ultraviolet irradiation test under the following ultraviolet irradiation test conditions for 800 hours, the color difference (L ₁ , a ₁ , b ₁ ) of the coating surface of the test plate was measured, and the color tone change before and after the test (ΔE ) The formula:
ΔE = [(L ₁ −L ₀ ) ² + (a ₁ −a ₀ ) ² + (b ₁ −b ₀ ) ² ] ^1/2
The ultraviolet color tone retention was evaluated based on the following evaluation criteria.

[Ultraviolet irradiation test conditions]
・ Testing machine: Metal weather meter (Daipura Wintes Co., Ltd., product number: KU-R5 type)
・ Irradiation: Irradiation for 4 hours in an atmosphere with a temperature of 65 ° C. and a relative humidity of 50% (irradiation intensity: 65 mW / cm ² )
-Wet: Wet for 4 hours in an atmosphere with a temperature of 65 ° C and a relative humidity of 98%-Water shower: Shower for 30 seconds before and after wetting

〔Evaluation criteria〕
◎: ΔE is less than 1 ○: ΔE is 1 or more and less than 3 Δ: ΔE is 3 or more and less than 5 ×: ΔE is 5 or more

  In the above evaluation criteria, there is a large difference in the color tone of the coating film visually between ◯ and △, and it is difficult to determine whether the coating film is colored in ◯, but the coating film is colored in △. I understand that.

(3) Freeze-thaw repeated stability After sealing the side surface of the test plate obtained above with a silicone bath bond [manufactured by Konishi Co., Ltd.], cool it to −20 ° C. in the air using a freeze-thaw tester. The operation of immersing in water at 20 ° C. for 1 hour after freezing for 2 hours was taken as 1 cycle, and the occurrence of cracks on the coating surface of the test plate was observed using a magnifying glass with a magnification of 30 times every 100 cycles. However, the above operation was performed for 300 cycles, and freeze-thaw repeated stability was evaluated based on the following evaluation criteria.

〔Evaluation criteria〕
◎: No problem even at 300 cycles ○: No problem at 200 cycles, but cracks occurred at 300 cycles Δ: No problems at 100 cycles, but cracks occurred at 200 cycles ×: Cracks occurred at 100 cycles

(4) Transparency According to JIS K7105, the difference in transparency (haze) between the polyester film and the coating film was measured using a turbidimeter [Nippon Denshoku Industries Co., Ltd., product number: NDH300A]. The transparency of was evaluated based on the following evaluation criteria.

〔Evaluation criteria〕
◎: Haze difference is less than 0.5% ○: Haze difference is 0.5% or more and less than 1% Δ: Haze difference is 1% or more and less than 2% ×: Haze difference is 2% or more

(5) Comprehensive evaluation Next, in each physical property, the overall score (maximum score: 200 points) was evaluated as 50 for ◎, 30 for ◯, 10 for △, and 0 for ×. The results are listed in the column of comprehensive evaluation in Table 3. In addition, what has even one x or xx in the evaluation is rejected.

  From the results shown in Table 3, it can be seen that any of the resin emulsions obtained in each Example forms a coating film excellent in ultraviolet color tone retention and transparency. Moreover, it turns out that the resin emulsion obtained by each Example forms the coating film excellent also in water resistance and freeze-thaw repetition stability. Therefore, it can be seen that all the resin emulsions obtained in each Example form a coating film that is comprehensively excellent in ultraviolet color tone retention, transparency, water resistance, and freeze-thaw repeat stability.

  The resin emulsion of the present invention can be suitably used for surface finishing of a substrate made of a material such as metal, glass, porcelain, concrete, siding board, resin, and the like. Therefore, the resin emulsion of the present invention is called, for example, a top coat coated on the surface of a ceramic building material, an automobile, a building, a civil engineering structure, etc., especially a building exterior, a ceramic building material, etc. It can be suitably used for existing top coats.

Claims (7)

  A resin emulsion containing a triazine-based ultraviolet absorber, wherein a monomer component containing a cycloalkyl (meth) acrylate having a cycloalkyl group having 3 to 12 carbon atoms is used as a resin raw material of the resin emulsion, The resin emulsion, wherein the content of the cycloalkyl (meth) acrylate having a cycloalkyl group having 3 to 12 carbon atoms in the monomer component is 15 to 70% by mass.   The resin emulsion according to claim 1, wherein the resin emulsion is a resin emulsion containing emulsion particles containing a triazine-based ultraviolet absorber.   The resin emulsion according to claim 2, wherein a triazine-based ultraviolet absorber is contained in the outermost layer of the emulsion particles.   A top coating composition comprising the resin emulsion according to claim 1.   The top-coat paint according to claim 4, wherein the top-coat paint is a clear paint for a top coat of an object to be coated.   A method for producing a resin emulsion containing a triazine-based ultraviolet absorber, wherein when the monomer component is polymerized in the presence of the triazine-based ultraviolet absorber, the monomer component has 3 to 12 carbon atoms. Using a monomer component containing a cycloalkyl (meth) acrylate having a cycloalkyl group, the content of the cycloalkyl (meth) acrylate having a cycloalkyl group having 3 to 12 carbon atoms in the monomer component is 15 to 15%. It adjusts to 70 mass%, The manufacturing method of the resin emulsion characterized by the above-mentioned.   The method for producing a resin emulsion according to claim 6, wherein the monomer component contains a triazine-based ultraviolet absorber.