JP2016069514A - Resin emulsion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a resin emulsion for forming a coating film comprehensively excellent in water resistance, water permeation resistance, low-temperature film-forming properties, extensibility and heat distortion resistance; and an aqueous coating composition containing the resin emulsion.SOLUTION: There is provided a resin emulsion containing emulsion particles having at least three layers: an outer resin layer, an intermediate resin layer and an inner resin layer, where the intermediate resin layer has a glass transition temperature higher than that of the resin layers other than the intermediate resin layer by 10°C or higher.SELECTED DRAWING: None

Description

  The present invention relates to a resin emulsion. More specifically, for example, the present invention relates to a resin emulsion that can be suitably used for applications such as an aqueous paint and an aqueous paint containing the resin emulsion. The resin emulsion of the present invention can be suitably used for applications such as water-based paints coated on the surface of a building exterior or a ceramic building material.

  In recent years, in order to avoid environmental problems due to the release of volatile organic compounds into the atmosphere, water-based paints using water-dispersed polymers such as water-soluble resin emulsions have been used instead of solvent-based paints. . However, water-based paints are generally inferior in the durability and appearance of coating films such as drying, water resistance, and weather resistance due to the use of water as a solvent compared to organic solvent-based paints. There is a technical problem that it is difficult to increase the coating film hardness.

  Accordingly, an aqueous coating composition having a specific ratio of two polymer components having different glass transition temperatures as an aqueous coating composition having improved coating film hardness and good coating film appearance and durability (for example, patents) Reference 1), water-based coating composition excellent in weather resistance, water resistance, discoloration resistance, crack resistance, polymerization stability, storage stability, warm water resistance, film-forming property, temperature resistance resistance and coating film appearance For example, an aqueous coating composition in which a multilayer structure particle having a core part and a shell part made of an acrylic polymer having a specific glass transition temperature is dispersed in water (see, for example, Patent Document 2) has been proposed.

  However, each of the water-based coating compositions has a drawback that it is inferior in film-forming property and frost damage resistance because it is necessary to increase the glass transition temperature of the shell portion of the particles in order to impart blocking resistance. is there.

  Therefore, in order to improve the blocking resistance, it is conceivable to use a water-soluble polymer having a high glass transition temperature and a low molecular weight, or increasing the pigment content. However, when a water-soluble polymer with a high glass transition temperature and a low molecular weight is used, there is a disadvantage that it is inferior in frost resistance, etc., and when the pigment content is increased, the film-forming property is lowered. Therefore, there is a disadvantage that the hot water whitening resistance is lowered.

  An aqueous polymer composition containing emulsion particles having an inner layer and an outer layer as an aqueous polymer composition that eliminates the drawbacks, wherein the inner layer has 75 to 100% by mass of a monomer having an alicyclic structure and the fat. The outer layer is formed of a polymer (I) obtained by emulsion polymerization of a monomer component containing 0 to 25% by mass of a monomer copolymerizable with a monomer having a ring structure, and the outer layer has a glass transition A polymer (II) having a temperature of 40 ° C. or lower is used, and the weight ratio of the polymer (I) to the polymer (II) [polymer (I) / polymer (II)] is 25/75 to 75 An aqueous polymer composition in which the total content of the polymer (I) and the polymer (II) in the emulsion particles is 50 to 100% by mass has been proposed (for example, see Patent Document 3). ).

  The aqueous polymer composition is excellent in weather resistance, warm water whitening resistance, blocking resistance and frost damage resistance, and therefore can be suitably used for water-based paints.

  However, in recent years, resin emulsions used for applications such as water-based paints can be easily formed even at low temperatures (low-temperature film-forming properties) and the film after film formation can be used in a low-temperature environment. Sufficiently stretchable properties (stretchability) are required, and the development of resin emulsions that form coatings that are comprehensively excellent in water resistance, water permeability resistance, low-temperature film formability, stretchability, and heat distortion resistance is desired. ing.

JP 2001-200181 A JP 2002-012816 A Japanese Patent Application Laid-Open No. 2011-246639

  The present invention has been made in view of the above prior art, and is a resin emulsion that forms a coating film that is comprehensively excellent in water resistance, water permeability resistance, low-temperature film formability, stretchability, and heat distortion resistance, and It is an object to provide an aqueous paint containing a resin emulsion.

The present invention
(1) A resin emulsion containing emulsion particles having at least three resin layers of an inner layer, an intermediate layer and an outer layer, wherein the glass transition temperature of the polymer constituting the intermediate layer constitutes a layer other than the intermediate layer A resin emulsion characterized by being 10 ° C. or more lower than any glass transition temperature of the polymer
(2) The resin emulsion according to (1), wherein the glass transition temperature of the polymer constituting the outer layer is 0 ° C. or higher.
(3) The resin emulsion according to (1) or (2), wherein the content of the outer layer in the emulsion particles is 10 to 50% by mass, and (4) according to any one of (1) to (3). The present invention relates to a water-based paint containing a resin emulsion.

  ADVANTAGE OF THE INVENTION According to this invention, the resin emulsion which forms the coating film excellent in water resistance, water permeability resistance, low-temperature film-forming property, extensibility, and heat-deformability comprehensively, and the water-based coating material containing the said resin emulsion are provided. The

  As described above, the resin emulsion of the present invention contains emulsion particles having at least three resin layers of an inner layer, an intermediate layer, and an outer layer. When the emulsion particles have three layers, an inner layer, an intermediate layer, and an outer layer, the layer existing between the inner layer and the outer layer is the intermediate layer. Further, when the emulsion particles have an inner layer, two or more intermediate layers, and an outer layer, it is preferable that one of a plurality of resin layers constituting the intermediate layer corresponds to the intermediate layer in the present invention. Therefore, in the present invention, the emulsion particles may contain layers other than the inner layer, the intermediate layer having the glass transition temperature, and the outer layer within a range that does not impair the object of the present invention.

  The resin emulsion of the present invention is characterized in that the glass transition temperature of the polymer constituting the intermediate layer of the emulsion particles is 10 ° C. or more lower than any glass transition temperature of the polymer constituting the layer other than the intermediate layer. . Since the resin emulsion of the present invention has the above-described configuration, it can improve the low-temperature film-forming property of a coating film composed of a resin emulsion containing the emulsion particles without reducing the hardness of the emulsion particles themselves, and is water resistant. It forms a coating film that is comprehensively excellent in water permeability, low-temperature film formability, extensibility, and heat distortion resistance.

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

  The glass transition temperature of the polymer is, for example, 95 ° C. for acrylic acid homopolymer, 130 ° C. for methacrylic acid homopolymer, 105 ° C. for methyl methacrylate homopolymer, and − for n-butyl acrylate homopolymer. 56 ° C., 20 ° C. for n-butyl methacrylate homopolymer, 107 ° C. for tert-butyl methacrylate homopolymer, −70 ° C. for 2-ethylhexyl acrylate homopolymer, 16 ° C. for cyclohexyl acrylate homopolymer, A homopolymer of cyclohexyl methacrylate is 83 ° C, a homopolymer of isobornyl methacrylate is 180 ° C, a homopolymer of hydroxyethyl methacrylate is 55 ° C, a homopolymer of styrene is 100 ° C, and γ-methacryloyloxypropyltrimethoxysilane (TMSMA) 70 ° C. is a homopolymer, a 4-methacryloyloxy-2,2,6,6 homopolymer of tetramethylpiperidine is 130 ° C..

  In this specification, the glass transition temperature of a polymer means the glass transition temperature calculated | required based on the said formula, unless there is particular notice. Special monomers, for example, monomers with unknown glass transition temperature such as polyfunctional monomers such as ethylene glycol di (meth) acrylate and trimethylolpropane tri (meth) acrylate When the total amount of the monomers whose glass transition temperature is unknown in the body component is 10% by mass or less, the glass transition temperature is determined using only the monomer whose glass transition temperature is known. When the total amount of 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 calculated | required by thermomechanical analysis (TMA) etc.

  The glass transition temperature of the polymer forming each layer can be easily adjusted by adjusting the composition of the monomer used as a raw material for the polymer constituting each layer.

  The glass transition temperature of the polymer constituting the intermediate layer of the emulsion particles is 10 ° C. or more lower than any glass transition temperature of the polymer constituting the layer other than the intermediate layer. From the viewpoint of forming a coating film that is comprehensively excellent in low-temperature film formability, extensibility, and heat distortion resistance, a temperature that is 15 ° C. or more lower than any glass transition temperature of the polymer constituting the layer other than the intermediate layer The temperature is preferably 20 ° C. or more, more preferably 25 ° C. or more, and even more preferably 30 ° C. or more.

  The polymer forming the inner layer can be obtained by polymerizing the monomer component for forming the inner layer.

  The monomer component for forming the inner layer is a monomer having an alicyclic structure from the viewpoint of forming a coating film having excellent water resistance, water permeability resistance, low temperature film formability, extensibility and heat distortion resistance. It is preferably included.

  In the monomer having an alicyclic structure, the alicyclic structure is preferably a cycloalkyl group having 4 to 20 carbon atoms, more preferably a cycloalkyl group having 4 to 12 carbon atoms. Examples of the monomer having an alicyclic structure include cycloalkyl (meth) acrylate and cycloalkylalkyl (meth) acrylate, and these monomers may be used alone or in combination of two or more. May be used in combination. Moreover, these monomers may have a substituent. Examples of the substituent include an alkyl group such as a methyl group and a tert-butyl group, a nitro group, a nitrile group, an alkoxyl group, an acyl group, a sulfone group, a hydroxyl group, and a halogen atom. It is not limited to illustration only.

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

  As the cycloalkyl (meth) acrylate, for example, a cycloalkyl group such as isobornyl (meth) acrylate, cyclohexyl (meth) acrylate and the like preferably has 4 to 20 carbon atoms, more preferably 4 to 10 cycloalkyl (meth) acrylates. These cycloalkyl (meth) acrylates may be used alone or in combination of two or more. Examples of the cycloalkylalkyl (meth) acrylate include carbon numbers of cycloalkyl groups such as cyclohexylmethyl (meth) acrylate, cyclohexylethyl (meth) acrylate, cyclohexylpropyl (meth) acrylate, and 4-methylcyclohexylmethyl (meth) acrylate. Are preferably 4 to 20, more preferably 4 to 10 cycloalkylalkyl (meth) acrylates. These cycloalkylalkyl (meth) acrylates may be used alone or in combination of two or more. May be.

  Among the monomers having an alicyclic structure, a cycloalkyl (meth) acrylate having a cycloalkyl group having 4 to 20 carbon atoms is preferable, and a cycloalkyl (meth) having a cycloalkyl group having 4 to 12 carbon atoms. Acrylates are more preferred, and isobornyl (meth) acrylate and cyclohexyl (meth) acrylate are more preferred. These cycloalkyl (meth) acrylates may be used alone or in combination.

  The content of the monomer having an alicyclic structure in the monomer component for forming the inner layer forms a coating film that is comprehensively excellent in water resistance, water permeability resistance, low temperature film formability, extensibility, and heat distortion resistance. From the viewpoint, it is preferably 25% by mass or more, more preferably 30% by mass or more, further preferably 35% by mass or more, and the upper limit is 100% by mass. Therefore, the monomer component for forming an inner layer may be composed only of a monomer having an alicyclic structure. Moreover, the monomer component for inner layer formation may contain a monomer copolymerizable with the monomer having an alicyclic structure within a range not impairing the object of the present invention.

  Examples of the monomer copolymerizable with the monomer having an alicyclic structure include aromatic monomers, ethylenically unsaturated monomers, and the like. You may use, and may use 2 or more types together. In addition, both the aromatic monomer and ethylenically unsaturated monomer referred to in the present specification mean a monomer having no alicyclic structure.

  Examples of aromatic monomers include styrene monomers and aralkyl (meth) acrylates, but the present invention is not limited to such examples.

  Examples of the styrenic monomer include styrene, α-methylstyrene, p-methylstyrene, tert-methylstyrene, chlorostyrene, vinyltoluene, and the like, but the present invention is limited only to such examples. is not. These monomers may be used alone or in combination of two or more. Styrene monomers have functional groups such as alkyl groups such as methyl and tert-butyl groups, nitro groups, nitrile groups, alkoxyl groups, acyl groups, sulfone groups, hydroxyl groups, and halogen atoms in the benzene ring. May be. Among the styrene monomers, styrene is preferable from the viewpoint of increasing the water resistance of the coating film.

  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 aralkyl (meth) acrylates may be used alone or in combination of two or more.

  Examples of the ethylenically unsaturated monomer include alkyl (meth) acrylate, hydroxyl group-containing (meth) acrylate, carboxyl group-containing monomer, oxo group-containing monomer, fluorine atom-containing monomer, and nitrogen atom-containing monomer. Examples include monomers, epoxy group-containing monomers, alkoxyalkyl (meth) acrylates, silane group-containing monomers, carbonyl group-containing monomers, aziridinyl group-containing monomers, and the present invention is only such examples. It is not limited to. These ethylenically unsaturated monomers may be used alone or in combination of two or more.

  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, n-lauryl (meth) acrylate, dodecyl (meth) Examples thereof include alkyl (meth) acrylates having 1 to 18 carbon atoms in ester groups such as acrylate and stearyl (meth) acrylate, but the present invention is not limited to such examples. These alkyl (meth) acrylates may be used alone or in combination of two or more.

  Examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4-hydroxy Examples include hydroxyl group-containing (meth) acrylates having 1 to 18 carbon atoms in the ester group such as butyl (meth) acrylate, but the present invention is not limited to such examples. These hydroxyl group-containing (meth) acrylates may be used alone or in combination of two or more.

  Examples of the carboxyl group-containing monomer include (meth) acrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, maleic anhydride, maleic acid monomethyl ester, maleic acid monobutyl ester, and itaconic acid monomethyl. Examples thereof include carboxyl group-containing aliphatic monomers such as esters, itaconic acid monobutyl ester, and vinyl benzoic acid, but the present 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, acrylic acid, methacrylic acid and itaconic acid are preferable, and acrylic acid and methacrylic acid are more preferable from the viewpoint of improving the dispersion stability of the emulsion particles.

  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 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, 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.

  Examples of the epoxy group-containing monomer include 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 such examples. 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, 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.

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

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

  Suitable monomers that can be copolymerized with a monomer having an alicyclic structure include, for example, aromatic monomers, alkyl (meth) acrylates, carboxyl group-containing monomers, and the like. The monomers may be used alone or in combination of two or more. Among the monomers copolymerizable with monomers having an alicyclic structure, a viewpoint of forming a coating film excellent in water resistance, water permeability resistance, low-temperature film formability, stretchability and heat distortion resistance. Therefore, styrene, alkyl (meth) acrylates having 1 to 8 carbon atoms in the alkyl group, and (meth) acrylic acid are more preferable.

  Further, in the present invention, from the viewpoint of imparting ultraviolet stability and ultraviolet absorptivity to the emulsion particles, an inner layer containing an ultraviolet-stable monomer, an ultraviolet-absorbing monomer, and the like within a range that does not hinder the object of the present invention. The monomer component used in the intermediate layer or outer layer may be contained. Among these layers, the monomer components used in the outer layer contain UV-stable monomers, UV-absorbing monomers, etc. from the viewpoint of efficiently imparting UV stability and UV-absorbing properties to the emulsion particles. It is preferable to make it.

  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- Crotonoylamino-2,2,6,6-tetramethylpiperidine, 4- (meth) acryloylamino-1,2,2,6,6-pentamethylpiperidine, 4-si No-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, these monomers may be used alone or in combination of two or more.

  Examples of the UV-absorbing monomer include benzotriazole-based UV-absorbing monomers and benzophenone-based UV-absorbing monomers, but the present invention is not limited to such examples. These 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 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-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.

  As a method for emulsion polymerization of the monomer component for forming the inner layer, for example, an aqueous medium containing a water-soluble organic solvent such as lower alcohol such as methanol and water, an emulsifier is dissolved in a medium such as water, and the mixture is stirred. Examples include a method of dropping an inner layer forming monomer component and a polymerization initiator, and a method of dropping an inner layer forming monomer component previously emulsified with an emulsifier and water into water or an aqueous medium. The present invention is not limited to such a method. 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. The medium may be charged in the reaction vessel in advance or used as a pre-emulsion. The medium may be used when a resin emulsion is produced by emulsion polymerization of monomer components as required.

  When the inner layer forming monomer component is emulsion polymerized, the inner layer forming monomer component, the emulsifier and the medium may be mixed and then emulsion polymerization may be performed. The emulsion may be emulsified by stirring and emulsion polymerization may be performed after preparing the pre-emulsion, or at least one of the inner layer forming monomer component, the emulsifier and the medium may be mixed with the remaining pre-emulsion. Emulsion polymerization may be performed. The inner layer forming monomer component, the emulsifier, and the medium may be added all at once, dividedly, or continuously dropped.

  When the intermediate layer and the outer layer are formed on the emulsion particles contained in the resin emulsion obtained above, the emulsion particles are emulsion-polymerized in the same manner as described above in the resin emulsion. An intermediate layer and an outer layer can be formed thereon. Further, when the outer layer is further formed on the emulsion particles on which the intermediate layer and the outer layer are formed as necessary, the monomer component is emulsion-polymerized in the resin emulsion in the same manner as described above. Further, an outer layer can be formed. Thus, a resin emulsion containing emulsion particles having a multilayer structure can be prepared by a multistage emulsion polymerization method.

  When preparing emulsion particles having a multilayer structure, one or more stages of emulsion polymerization may be performed before the emulsion polymerization for forming the inner layer, and the emulsion polymerization for forming the inner layer and the intermediate polymerization may be performed. One-stage or multiple-stage emulsion polymerization may be performed between the emulsion polymerization forming the layer. Moreover, you may perform one step or multiple steps | paragraphs of emulsion polymerization between the emulsion polymerization which forms the said intermediate | middle layer, and the emulsion polymerization which forms the said outer layer. Furthermore, after the emulsion polymerization for forming the outer layer, one or more stages of emulsion polymerization may be performed.

  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. Polyoxyethylene alkyl sulfonate salts; polyoxyethylene alkyl sulfate salts; polyoxyethylene alkyl aryl sulfate salts; dialkyl sulfosuccinates; aryl sulfonic acid-formalin condensates; ammonium laurate, sodium stearate, etc. Fatty acid salt; bis ( (Rioxyethylene polycyclic phenyl ether) methacrylate sulfonate salt, propenyl-alkylsulfosuccinate ester salt, (meth) acrylic acid polyoxyethylene sulfonate salt, (meth) acrylic acid polyoxyethylene phosphonate salt, allyloxymethylalkyloxypoly Sulfuric acid ester having an allyl group, such as sulfonate salt of oxyethylene or a salt thereof; Sulfuric acid ester salt of allyloxymethylalkoxyethyl polyoxyethylene, polyoxyalkylene alkenyl ether ammonium sulfate, and the like. It is not limited to.

  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 Examples include condensation products with amines, allyloxymethylalkoxyethylhydroxypolyoxyethylene, and polyoxyalkylene alkenyl ethers, but the present invention is not limited to such examples.

  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; polyvinylpyrrolidone; polyhydroxyalkyl (meth) acrylates such as polyhydroxyethyl acrylate; Although the copolymer etc. which use 1 or more types as a copolymerization component are mentioned, this invention is not limited only to this illustration.

  Further, from the viewpoint of forming a coating film having excellent water resistance, water permeability resistance and heat distortion resistance, an emulsifier having a polymerizable group, that is, a so-called reactive emulsifier is preferable, and from the viewpoint of environmental protection, non-nonylphenyl type An emulsifier is preferred.

  As the reactive emulsifier, for example, propenyl-alkylsulfosuccinic acid ester salt, (meth) acrylic acid polyoxyethylene sulfonate salt, (meth) acrylic acid polyoxyethylene phosphonate salt [for example, manufactured by Sanyo Chemical Industries, Ltd., Product name: Eleminol RS-30, etc.], polyoxyethylene alkylpropenyl phenyl ether sulfonate salt [for example, product name: Aqualon HS-10, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.], allyloxymethylalkyloxypolyoxyethylene Sulfonate salt [eg, Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon KH-10, etc.], Sulphonate salt of allyloxymethylnonylphenoxyethylhydroxypolyoxyethylene [eg, ADEKA Corporation, trade name: ADEKA Rear soap SE-10 Allyloxymethylalkoxyethylhydroxy polyoxyethylene sulfate ester salt [for example, manufactured by ADEKA, trade name: Adekaria soap SR-10, SR-30, etc.], bis (polyoxyethylene polycyclic phenyl ether) Methacrylated sulfonate salts [for example, manufactured by Nippon Emulsifier Co., Ltd., trade name: Antox MS-60, etc.], allyloxymethylalkoxyethylhydroxypolyoxyethylene [for example, manufactured by ADEKA Corporation, trade name: Adeka Soap ER -20, etc.], polyoxyethylene alkylpropenyl phenyl ether [for example, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon RN-20, etc.], allyloxymethylnonylphenoxyethylhydroxypolyoxyethylene [for example, Co., Ltd. Made by ADEKA, quotient 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 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 polymerization stability per 100 parts by mass of the monomer component for forming the inner layer. Further, it is more preferably 3 parts by mass or more, and preferably 10 parts by mass or less, more preferably 6 parts by mass or less, further preferably from the viewpoint of forming a coating film excellent in water resistance, water permeability resistance and heat distortion resistance. Is 5 parts by mass or less, more preferably 4 parts by mass or less.

  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 ammonium persulfate and potassium 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 inner layer forming monomer component is preferably 0.05 parts by mass from the viewpoint of increasing the polymerization rate and reducing the remaining amount of the unreacted inner layer forming monomer component. Above, more preferably 0.1 parts by mass or more, from the viewpoint of forming a coating film excellent in water resistance, water permeability resistance and heat distortion resistance, preferably 1 part by mass or less, more preferably 0.5 parts by mass It is as follows.

  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 before or after the addition of the inner layer forming monomer component into 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.

  Moreover, in order to adjust the weight average molecular weight of resin which comprises emulsion particle | grains, a chain transfer agent can be used. 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. Although a styrene dimer etc. are mentioned, this invention is not limited only to this illustration. These chain transfer agents may be used alone or in combination of two or more. The amount of the chain transfer agent per 100 parts by mass of the inner layer forming monomer component is preferably 0.01 to 10 parts by mass from the viewpoint of appropriately adjusting the weight average molecular weight of the emulsion particles.

  Moreover, you may add additives, such as a pH buffer, a chelating agent, and a film-forming aid, in the reaction system as needed. Since the amount of the additive varies depending on the type, it cannot be determined unconditionally. However, it is usually about 0.01 to 5 parts by mass, more preferably 0, per 100 parts by mass of the inner layer forming monomer component. About 1 to 3 parts by mass.

  The atmosphere for emulsion polymerization of the inner layer forming 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.

  The polymerization temperature for emulsion polymerization of the inner layer forming monomer component is not particularly limited, but is usually preferably 50 to 100 ° C, more preferably 60 to 95 ° C. The polymerization temperature may be constant or may be changed during the polymerization reaction.

  The polymerization time required for emulsion polymerization of the monomer component for forming the inner layer cannot be determined unconditionally because it varies depending on the polymerization temperature, etc., but may be appropriately set according to the progress of the polymerization reaction. 1 to 4 hours.

  In addition, when carrying out emulsion polymerization of the monomer component for inner layer formation, you may make it neutralize part or all of the acidic group which the obtained polymer has with a neutralizing agent. The neutralizing agent may be used after the monomer component is added in the final stage. For example, the neutralizing agent may be used between the first stage polymerization reaction and the second stage polymerization reaction. It may be used at the end of the polymerization reaction, or after forming the outer layer of emulsion particles.

  Examples of the neutralizing agent include alkali metal and alkaline earth metal hydroxides such as sodium hydroxide; alkali metal and alkaline earth metal carbonates such as calcium carbonate; and organic amines such as ammonia and monomethylamine. Although an alkaline substance is mentioned, this invention is not limited only to this illustration. Among these neutralizing agents, an alkaline substance having volatility such as ammonia is preferable from the viewpoint of improving weather resistance and hot water whitening resistance.

  In addition, when the monomer component is subjected to emulsion polymerization, an appropriate amount of a silane coupling agent may be used from the viewpoint of forming a coating film excellent in water resistance, water permeability extension resistance and heat distortion resistance. Examples of the silane coupling agent include 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.

  By polymerizing the inner layer-forming monomer component as described above, a polymer forming the inner layer is obtained in the form of emulsion particles.

  The polymer forming the inner layer may have a crosslinked structure. The weight average molecular weight of the polymer forming the inner layer is such that the polymer forming the inner layer has water resistance, water permeability and heat distortion resistance regardless of whether the polymer having the inner layer has a crosslinked structure or not. From the viewpoint of forming an excellent coating film, the number is preferably 100,000 or more, more preferably 300,000 or more, further preferably 550,000 or more, and still more preferably 600,000 or more. The upper limit of the weight average molecular weight of the polymer forming the inner layer is not particularly limited when it has a crosslinked structure, and it is difficult to measure the weight average molecular weight. From the viewpoint of forming a coating film excellent in film properties and extensibility, it is preferably 5 million or less.

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

  The glass transition temperature of the polymer forming the inner layer is preferably 5 ° C. or more from the viewpoint of forming a coating film that is comprehensively excellent in water resistance, water permeability resistance, low-temperature film formability, extensibility, and heat distortion resistance. More preferably 10 ° C or higher, even more preferably 15 ° C or higher, still more preferably 20 ° C or higher, preferably 150 ° C or lower, more preferably 140 ° C or lower, still more preferably 130 ° C or lower, still more preferably 120 ° C. It is as follows.

  Next, after forming emulsion particles made of a polymer constituting the inner layer, an intermediate layer is formed on the surface of the emulsion particles. The intermediate layer can be formed on the surface of the emulsion particles composed of the polymer constituting the inner layer by emulsion polymerization of the monomer component for forming the intermediate layer in the presence of the emulsion particles.

  When the monomer component for forming the intermediate layer is emulsion polymerized, the monomer component for forming the intermediate layer is emulsified after the polymerization reaction rate of the polymer forming the inner layer reaches 90% or more, preferably 95% or more. Polymerization is preferable from the viewpoint of forming a layer separation structure in the emulsion particles.

  In addition, after forming an inner layer, before forming an intermediate | middle layer, in the range which does not inhibit the objective of this invention, the layer which consists of another polymer may be formed as needed. Therefore, in the resin emulsion of the present invention, after the inner layer is formed, before the intermediate layer is formed, an operation for forming a layer made of another polymer, if necessary, within a range not inhibiting the purpose of the present invention. May be included.

  As the monomer component for forming an intermediate layer, those exemplified for the monomer component for forming an inner layer can be used. Examples of the monomer component for forming the intermediate layer include aromatic monomers, monomers having an alicyclic structure, alkyl (meth) acrylates, hydroxyl group-containing (meth) acrylates, carboxyl group-containing monomers, 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 Although a containing monomer etc. are mentioned, this invention is not limited only to this illustration. These monomers may be used alone or in combination of two or more.

  The monomer component for forming the intermediate layer is a single monomer having an alicyclic structure from the viewpoint of forming a coating film that is comprehensively excellent in water resistance, water permeability resistance, low-temperature film formability, extensibility, and heat distortion resistance. The body is preferably included. As a monomer which has an alicyclic structure, the thing similar to the monomer which has an alicyclic structure used for the monomer component for inner layer formation can be illustrated.

  Among the monomers having an alicyclic structure, a cycloalkyl (meth) acrylate having a cycloalkyl group having 4 to 20 carbon atoms is preferable, and a cycloalkyl (meth) having a cycloalkyl group having 4 to 12 carbon atoms. Acrylates are more preferred, and isobornyl (meth) acrylate and cyclohexyl (meth) acrylate are more preferred. Isobornyl (meth) acrylate and cyclohexyl (meth) acrylate may be used alone or in combination.

  The content of the monomer having an alicyclic structure in the monomer component for forming the intermediate layer forms a coating film that is comprehensively excellent in water resistance, water permeability resistance, low temperature film formability, extensibility, and heat distortion resistance. In view of the above, it is preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 15% by mass or more, preferably 65% by mass or less, more preferably 60% by mass or less, and further preferably 55% by mass. It is as follows.

  In addition, the monomer component for forming the intermediate layer may be an alkyl having 4 to 12 carbon atoms in the alkyl group from the viewpoint of forming a coating film that is comprehensively excellent in water resistance, water permeability, and heat distortion resistance. It is preferable that an oxo group-containing monomer such as (meth) acrylate or ethylene glycol di (meth) acrylate is included, and an alkyl (meth) acrylate having 4 to 12 carbon atoms in the alkyl group is included. It is more preferable.

  Examples of the alkyl (meth) acrylate having an alkyl group having 4 to 12 carbon atoms include n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, and sec-butyl (meth) acrylate. , 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, and the like, but the present invention is not limited to such examples. These alkyl (meth) acrylates may be used alone or in combination of two or more. Among these alkyl (meth) acrylates, n-butyl (meth) acrylate is used from the viewpoint of forming a coating film that is comprehensively excellent in water resistance, water permeability resistance, low-temperature film formability, extensibility, and heat distortion resistance. Alkyl (meth) acrylates having 4 to 8 carbon atoms in the alkyl group, such as isobutyl (meth) acrylate, tert-butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, are preferred.

  The content of the alkyl (meth) acrylate having an alkyl group with 4 to 12 carbon atoms in the monomer component for forming the intermediate layer is comprehensive in terms of water resistance, water permeability resistance, low temperature film formability, extensibility, and heat distortion resistance. From the viewpoint of forming an excellent coating film, it is preferably 35% by mass or more, more preferably 40% by mass or more, further preferably 45% by mass or more, preferably 95% by mass or less, more preferably 90% by mass. Hereinafter, it is more preferably 85% by mass or less.

  The method and polymerization conditions for emulsion polymerization of the monomer component for forming the intermediate layer may be the same as the method and polymerization conditions for emulsion polymerization of the monomer for forming the inner layer.

  By emulsion polymerization of the monomer component for forming the intermediate layer as described above, emulsion particles in which the polymer forming the intermediate layer is formed on the surface of the inner layer can be obtained. It should be noted that a layer made of another polymer may be formed on the surface of the intermediate layer, if necessary, as long as the object of the present invention is not impaired.

  The polymer forming the intermediate layer may have a crosslinked structure. The weight average molecular weight of the polymer forming the intermediate layer is such that the polymer forming the intermediate layer has water resistance, water permeability resistance and heat resistance, regardless of whether the polymer having the intermediate layer has a crosslinked structure or not. From the viewpoint of forming a coating film excellent in deformability, it is preferably 100,000 or more, more preferably 300,000 or more, further preferably 550,000 or more, and still more preferably 600,000 or more. The upper limit value of the weight average molecular weight of the polymer forming the intermediate layer is not particularly limited when it has a crosslinked structure, since it is difficult to measure the weight average molecular weight. From the viewpoint of forming a coating film excellent in film formability and extensibility, it is preferably 5 million or less.

  The glass transition temperature of the polymer forming the intermediate layer is preferably 20 ° C. or less, more preferably 10 ° C. or less, even more preferably 5 ° C. or less, from the viewpoint of improving the low-temperature film formability and stretchability of the coating film. More preferably, it is 0 degreeC or less, More preferably, it is -5 degreeC or less. The glass transition temperature of the polymer forming the intermediate layer is preferably −80 ° C. or higher, more preferably −70 ° C. or higher, from the viewpoint of improving the water resistance, water permeability and heat distortion resistance of the coating film. Preferably it is -60 ° C or more.

  The glass transition temperature of the polymer forming the intermediate layer can be easily adjusted by adjusting the composition of the monomer used for the monomer component for forming the intermediate layer.

  Next, after forming emulsion particles having an intermediate layer, an outer layer is formed on the surface of the emulsion particles. The outer layer can be formed on the surface of the emulsion particles by emulsion polymerization of the outer layer forming monomer component in the presence of the emulsion particles having an intermediate layer.

  When the outer layer forming monomer component is emulsion polymerized, the outer layer forming monomer component is emulsion polymerized after the polymerization reaction rate of the polymer forming the intermediate layer reaches 90% or more, preferably 95% or more. From the viewpoint of forming a layer-separated structure in the emulsion particles.

  In addition, after forming an intermediate | middle layer, before forming an outer layer, the layer which consists of another polymer may be formed if needed in the range which does not inhibit the objective of this invention. Therefore, in the resin emulsion of the present invention, after forming the intermediate layer and before forming the outer layer, an operation for forming a layer made of another polymer, if necessary, within a range in which the object of the present invention is not hindered. May be included.

  As the monomer component for forming the outer layer, those exemplified for the monomer component for forming the inner layer can be used. More specifically, as the monomer component for forming the outer layer, for example, an aromatic monomer, a monomer having an alicyclic structure, an alkyl (meth) acrylate, a hydroxyl group-containing (meth) acrylate, a carboxyl group-containing Monomer, 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 Examples include monomers and aziridinyl group-containing monomers, but the present invention is not limited to such examples. These monomers may be used alone or in combination of two or more.

  The monomer component for forming the outer layer preferably contains a monomer having an alicyclic structure from the viewpoint of forming a coating film excellent in water resistance, water permeability resistance and heat distortion resistance. As a monomer which has an alicyclic structure, the thing similar to the monomer which has an alicyclic structure used for the monomer component for inner layer formation can be illustrated.

  Among the monomers having an alicyclic structure, a cycloalkyl (meth) acrylate having a cycloalkyl group having 4 to 20 carbon atoms is preferable, and a cycloalkyl (meth) having a cycloalkyl group having 4 to 12 carbon atoms. Acrylates are more preferred, and isobornyl (meth) acrylate and cyclohexyl (meth) acrylate are more preferred. Isobornyl (meth) acrylate and cyclohexyl (meth) acrylate may be used alone or in combination.

  The content of the monomer having an alicyclic structure in the monomer component for forming the outer layer is preferably 5% by mass or more from the viewpoint of forming a coating film excellent in water resistance, water permeability resistance and heat distortion resistance. Preferably it is 10 mass% or more, More preferably, it is 15 mass% or more, The upper limit is 100 mass% or less, Preferably it is 97 mass% or less.

  The method and polymerization conditions for emulsion polymerization of the outer layer forming monomer component may be the same as the method and polymerization conditions for emulsion polymerization of the inner layer forming monomer.

  By emulsion polymerization of the outer layer forming monomer component as described above, emulsion particles in which the polymer forming the outer layer is formed on the surface of the intermediate layer can be obtained. In addition, on the surface of the outer layer, a layer made of another polymer may be formed as necessary within a range that does not impair the object of the present invention.

  The polymer forming the outer layer may have a crosslinked structure. The weight average molecular weight of the polymer forming the outer layer is such that the polymer forming the outer layer has water resistance, water permeability resistance and heat distortion resistance regardless of whether the polymer having the outer layer has a crosslinked structure or not. From the viewpoint of forming an excellent coating film, the number is preferably 100,000 or more, more preferably 300,000 or more, further preferably 550,000 or more, and still more preferably 600,000 or more. The upper limit of the weight average molecular weight of the polymer forming the outer layer is not particularly limited because it is difficult to measure the weight average molecular weight when it has a crosslinked structure, but when it does not have a crosslinked structure, the low temperature From the viewpoint of forming a coating film excellent in film properties and extensibility, it is preferably 5 million or less.

  The glass transition temperature of the polymer forming the outer layer is preferably from −15 ° C. or higher, more preferably from −5 ° C. or higher, even more preferably from the viewpoint of forming a coating film excellent in water resistance, water permeability and heat distortion resistance. 0 ° C. or higher, more preferably 5 ° C. or higher. From the viewpoint of improving the low-temperature film formability and extensibility of the coating film, preferably 150 ° C. or lower, more preferably 120 ° C. or lower, more preferably 100 ° C. or lower, Still more preferably, it is 90 degrees C or less.

  The glass transition temperature of the polymer forming the outer layer can be easily adjusted by adjusting the composition of the monomer used for the monomer component for forming the outer layer.

  Further, the glass transition temperature of the entire emulsion particles is preferably 0 ° C. or higher from the viewpoint of forming a coating film that is comprehensively excellent in water resistance, water permeability resistance, low-temperature film formability, extensibility, and heat distortion resistance. Preferably it is 5 degreeC or more, More preferably, it is 10 degreeC or more, Preferably it is 50 degrees C or less, More preferably, it is 45 degrees C or less, More preferably, it is 40 degrees C or less.

  The content of the outer layer in the emulsion particles is preferably 10% or more, more preferably from the viewpoint of forming a coating film that is comprehensively excellent in water resistance, water permeability resistance, low-temperature film formability, extensibility, and heat distortion resistance. 15% or more, more preferably 20% or more, preferably 50% or less, more preferably 45% or less, and still more preferably 40% or less.

  Further, the content of the inner layer in the emulsion particles is preferably 10% or more from the viewpoint of forming a coating film that is comprehensively excellent in water resistance, water permeability resistance, low temperature film formability, extensibility, and heat distortion resistance. Preferably it is 15% or more, More preferably, it is 20% or more, Preferably it is 65% or less, More preferably, it is 60% or less, More preferably, it is 55% or less. The content of the intermediate layer in the emulsion particles is preferably 15% or more, more preferably, from the viewpoint of forming a coating film that is comprehensively excellent in water resistance, water permeability resistance, low temperature film formability, extensibility, and heat distortion resistance. Is 20% or more, more preferably 25% or more, preferably 65% or less, more preferably 60% or less, and still more preferably 55% or less.

  The total content of the inner layer, the intermediate layer, and the outer layer in the emulsion particles is preferably from the viewpoint of forming a coating film that is comprehensively excellent in water resistance, water permeability resistance, low temperature film formability, extensibility, and heat distortion resistance. 60 mass% or more, More preferably, it is 70 mass% or more, it is so preferable that the said content rate is large, and the upper limit is 100 mass%.

  In the present invention, the content of the monomer having an alicyclic structure in all monomer components used as a raw material for the polymer constituting the emulsion particles is water resistance, water resistance, low temperature film formation. From the viewpoint of forming a coating film that is comprehensively excellent in properties, extensibility and heat distortion resistance, preferably 10% by mass or more, more preferably 15% by mass or more, and further preferably 20% by mass or more. The content of the monomer other than the monomer having an alicyclic structure in all monomer components used as a raw material for the constituting polymer is preferably 60% by mass or less, more preferably 85% by mass. Hereinafter, it is more preferably 80% by mass or less.

  The resin emulsion of the present invention contains emulsion particles prepared as described above.

  The nonvolatile content in the resin emulsion of the present invention 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. More preferably, it is 60 mass% or less.

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

  From the viewpoint of improving the storage stability of the emulsion particles, the average particle diameter of the emulsion particles is preferably 30 nm or more, more preferably 50 nm or more, and even more preferably 70 nm or more, and is excellent in water resistance, water permeability resistance and heat distortion resistance. From the viewpoint of forming an excellent coating film, the thickness is preferably 250 nm or less, more preferably 200 nm or less. The emulsion particles prepared based on the above method usually have the average particle size.

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

  The resin emulsion of this invention is obtained as mentioned above. The resin emulsion of the present invention can be suitably used for, for example, an aqueous paint.

  In addition, the resin emulsion of this invention may contain other resin emulsions other than the said resin emulsion in the range which does not inhibit the objective of this invention.

  The resin emulsion of the present invention can be used as an aqueous paint as it is, but if necessary, it can be used as an aqueous paint by mixing with other components.

  In the case where the resin emulsion of the present invention is used in an aqueous coating material, crosslinkability can be imparted by incorporating a crosslinking agent. As a crosslinking agent, a crosslinking reaction may be started at room temperature, or a crosslinking reaction may be initiated by heat. By containing a crosslinking agent in the resin emulsion of the present invention, water resistance and water permeability resistance can be improved.

  Suitable crosslinking agents include, for example, oxazoline group-containing compounds, hydrazine compounds, isocyanate group-containing compounds, aminoplast polymers, and the like. These crosslinking agents may be used alone or in combination of two or more. Among these crosslinking agents, an oxazoline group-containing compound is preferable from the viewpoint of forming a coating film excellent in water resistance and water permeability.

  The oxazoline group-containing compound is a compound having in the molecule two or more oxazoline groups that can react with the carboxyl group that the carboxyl group-containing monomer used as the monomer component has as a functional group.

  Examples of the oxazoline group-containing compound include 2,2′-bis (2-oxazoline), 2,2′-methylene-bis (2-oxazoline), 2,2′-ethylene-bis (2-oxazoline), 2 , 2'-trimethylene-bis (2-oxazoline), 2,2'-tetramethylene-bis (2-oxazoline), 2,2'-hexamethylene-bis (2-oxazoline), 2,2'-octamethylene -Bis (2-oxazoline), 2,2'-ethylene-bis (4,4'-dimethyl-2-oxazoline), 2,2'-p-phenylene-bis (2-oxazoline), 2,2'- m-phenylene-bis (2-oxazoline), 2,2′-m-phenylene-bis (4,4′-dimethyl-2-oxazoline), bis (2-oxazolinylcyclohexane) sulfi , Bis (2-oxazolinyl sulfonyl norbornane) sulfide, but like oxazoline ring-containing polymer, the present invention is not limited only to those exemplified. These oxazoline group-containing compounds may be used alone or in combination of two or more. Among the oxazoline group-containing compounds, from the viewpoint of improving the reactivity, a water-soluble oxazoline group-containing compound is preferable, and a water-soluble oxazoline ring-containing polymer is more preferable.

  The oxazoline ring-containing polymer contains an addition-polymerizable oxazoline as an essential component, and can be easily prepared by polymerizing a monomer component containing a monomer copolymerizable with the addition-polymerizable oxazoline as necessary. Can do.

  Examples of the addition polymerizable oxazoline include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, Examples include 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline. It is not limited to only. These addition polymerizable oxazolines may be used alone or in combination of two or more. Among these addition-polymerizable oxazolines, 2-isopropenyl-2-oxazoline is preferable because it is easily available.

  Examples of monomers copolymerizable with the addition polymerizable oxazoline include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, and tert-butyl (meth) acrylate. , Cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2- Hydroxypropyl (meth) acrylate, monoesterified product of (meth) acrylic acid and polyethylene glycol, 2-aminoethyl (meth) acrylate and its salt, caprolactone modified product of (meth) acrylic acid, methacryloylio (Meth) acrylic acid esters such as cis-2,2,6,6-tetramethylpiperidine, methacryloyloxy-1,2,2,6,6-pentamethylpiperidine; sodium (meth) acrylate, (meth) acrylic (Meth) acrylates such as potassium acid and ammonium (meth) acrylate; unsaturated nitriles such as (meth) acrylonitrile; (meth) acrylamide, N-methylol (meth) acrylamide, N- (2-hydroxyethyl) ( Unsaturated amides such as (meth) acrylamide; Vinyl esters such as vinyl acetate and vinyl propionate; Vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; Halogens such as vinyl chloride, vinylidene chloride and vinyl fluoride Contains α, β-unsaturated Aliphatic hydrocarbon compounds; α, β-unsaturated aromatic hydrocarbon compounds such as styrene, α-methylstyrene, sodium styrenesulfonate and the like are exemplified, but the present invention is not limited to such examples. . These monomers copolymerizable with the addition-polymerizable oxazoline may be used alone or in combination of two or more.

  Oxazoline group-containing compounds are easily commercially available as, for example, Nippon Shokubai Co., Ltd., trade names: Epocross WS-500, Epocross WS-700, Epocross K-2010, Epocross K-2020, Epocross K-2030, etc. can do. Among these, from the viewpoint of improving reactivity, water-soluble oxazoline group-containing compounds such as Nippon Shokubai Co., Ltd., trade names: Epocross WS-500 and Epocross WS-700 are preferable.

  Examples of the hydrazine compound include adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, isophthalic acid dihydrazide dihydradide dihydradide dihydradide However, the present invention is not limited to this example, and there is no sodium. Of these, adipic acid dihydrazide is preferred.

  The isocyanate group-containing compound is a compound containing an isocyanate group that can react with a hydroxyl group that the hydroxyl group-containing monomer used as the monomer component has as a functional group.

  Examples of the isocyanate group-containing compound include water-dispersed (block) polyisocyanate. In addition, (block) polyisocyanate means polyisocyanate and / or block polyisocyanate.

  Examples of the water-dispersed polyisocyanate include those obtained by dispersing a polyisocyanate imparted with hydrophilicity by a polyethylene oxide chain in water with an anionic dispersant or a nonionic dispersant.

  Examples of the polyisocyanate include diisocyanates such as hexamethylene diisocyanate and isophorone diisocyanate; and polyisocyanate derivatives (modified products) of these diisocyanates such as trimethylolpropane adduct, burette, and isocyanurate. The present invention is not limited to such examples. These polyisocyanates may be used alone or in combination of two or more.

  Water-dispersed polyisocyanates are, for example, Nippon Polyurethane Industry Co., Ltd., trade names: Aquanate 100, Aquanate 110, Aquanate 200, Aquanate 210, etc .; Sumika Bayer Urethane Co., Ltd., trade name: Bihijoule TPLS-2032, SUB-isocyanate L801, etc .; manufactured by Mitsui Takeda Chemical Co., Ltd., trade names: Takenate WD-720, Takenate WD-725, Takenate WD-220, etc .; It can be easily obtained commercially as D-56 or the like.

  The water-dispersed block polyisocyanate is obtained by blocking the isocyanate group of the water-dispersed polyisocyanate with a blocking agent. Examples of the blocking agent include diethyl malonate, ethyl acetoacetate, ε-caprolactam, butanone oxime, cyclohexanone oxime, 1,2,4-triazole, dimethyl-1,2,4-triazole, and 3,5-dimethylpyrazole. , Imidazole and the like can be mentioned, but the present invention is not limited to such examples. These blocking agents may be used alone or in combination of two or more. Among these blocking agents, those that cleave at a temperature of 160 ° C. or lower, preferably 150 ° C. or lower are desirable. Suitable blocking agents include, for example, butanone oxime, cyclohexanone oxime, 3,5-dimethylpyrazole and the like. Of these, butanone oxime is more preferred.

  The water-dispersed block polyisocyanate is, for example, manufactured by Mitsui Takeda Chemical Co., Ltd., trade names: Takenate WB-720, Takenate WB-730, Takenate WB-920, etc .; manufactured by Sumika Bayer Urethane Co., Ltd. BL116, Bihijoule BL5140, Bihijoule BL5235, Bihijoule TPLS2186, Death Module VPLS2310, etc. can be easily obtained commercially.

  The aminoplast polymer is an addition condensate of a compound having an amino group such as melamine or guanamine with formaldehyde, and is also called an amino polymer.

  Examples of the aminoplast polymer include dimethylol melamine, trimethylol melamine, tetramethylol melamine, pentamethylol melamine, hexamethylol melamine, fully alkyl methylated melamine, fully alkyl butylated melamine, fully alkyl isobutylated melamine, Melamine polymers such as fully alkyl mixed etherified melamine, methylol group methylated melamine, imino group methylated melamine, methylol group mixed etherified melamine, imino group mixed etherified melamine; butylated benzoguanamine, methyl / ethyl Examples include mixed alkylated benzoguanamine, methyl / butyl mixed alkylated benzoguanamine, and guanamine polymers such as butylated glycoluril. However, the present invention is limited to such examples. Not intended to be. These aminoplast polymers may be used alone or in combination of two or more.

  Examples of the aminoplast polymer are those manufactured by Mitsui Cytec Co., Ltd., trade names: My Coat 506, My Coat 1128, Cymel 232, Cymel 235, Cymel 254, Cymel 303, Cymel 325, Cymel 370, Cymel 771, Cymel 1170, and the like. As commercially available.

  The amount of aminoplast polymer is usually determined by the weight ratio of the solid content of the polymer contained in the emulsion particles to the solid content of the aminoplast polymer [polymer solid content / solid content of aminoplast polymer]. It is preferable to adjust so that it may become 60 / 40-99 / 1.

  In the present invention, in addition to the crosslinking agent described above, for example, a carbodiimide compound; a crosslinking agent such as 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.

  If necessary, the water-based paint may contain a pigment. Examples of the pigment include organic pigments and inorganic pigments, and these may be used alone or in combination of two or more.

  Examples of organic pigments include azo pigments such as benzidine and hansa yellow, azomethine pigments, methine pigments, anthraquinone pigments, phthalocyanine pigments such as phthalocyanine blue, perinone pigments, perylene pigments, diketopyrrolopyrrole pigments, thioindigo pigments, and iminoisoindoline. Pigments, iminoisoindolinone pigments, quinacridone pigments such as quinacridone red and quinacridone violet, flavantron pigments, indanthrone pigments, anthrapyrimidine pigments, carbazole pigments, monoarylide yellow, diaryride yellow, benzimidazolone yellow, tolyl orange , Naphthol orange, quinophthalone pigment, and the like, but 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, antimony trioxide, zinc white, lithopone, lead white, red iron oxide, black iron oxide, iron oxide, chromium oxide green, carbon black, yellow lead, molybdenum red, ferrocyanide Pigment with flat shape such as ferric (Prussian blue), ultramarine, lead chromate, mica, clay, aluminum powder, talc, aluminum silicate, calcium carbonate, magnesium hydroxide, aluminum hydroxide And extender pigments such as barium sulfate and magnesium carbonate, but the present invention is not limited to such examples. These inorganic pigments may be used alone or in combination of two or more.

  The amount of the pigment per 100 parts by mass of the nonvolatile content of the resin emulsion is preferably 20 parts by mass or more, more preferably 40 parts by mass or more from the viewpoint of forming a coating film excellent in water resistance and water permeability. From the viewpoint of forming a coating film excellent in film formability and extensibility, it is preferably 190 parts by mass or less.

  In addition, the water-based paint includes, for example, an ultraviolet absorber, an ultraviolet stabilizer, a filler, a leveling agent, a dispersant, a thickener, a wetting agent, a plasticizer, a stabilizer, within the range in which the object of the present invention is not hindered. Additives such as dyes and antioxidants may be contained in appropriate amounts.

  Since the water-based paint contains the resin emulsion of the present invention, it can be suitably used for, for example, ceramic building materials. 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.

  The water-based paint may be applied alone as a single layer, or may be applied by recoating two or more layers. When the coating is performed by recoating two or more layers, only a part of the layers may be formed of the water-based paint of the present invention, or all layers may be formed of the water-based paint 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. When applying the paint, for example, spray, roller, brush, or iron can be used.

  As described above, the resin emulsion of the present invention has at least three resin layers of an inner layer, an intermediate layer, and an outer layer, and the glass transition temperature of the polymer constituting the intermediate layer constitutes a layer other than the intermediate layer. Since the glass transition temperature is 10 ° C. or more lower than any glass transition temperature of the polymer to be polymerized, the elongation at low temperature of the coating film made of a resin emulsion containing the emulsion particles (low-temperature film formation) is achieved without reducing the hardness of the emulsion particles themselves. Therefore, it is possible to form a coating film which is comprehensively excellent in water resistance, water permeability resistance, low temperature film-forming property, extensibility and heat distortion resistance. Therefore, the resin emulsion of the present invention can be suitably used for, for example, a water-based paint that is applied to the exterior of a building, a ceramic building material, or the like.

  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 Examples, “part” means “part by mass” and “%” means “mass%” unless otherwise specified.

Example 1
In a flask equipped with a dropping funnel, a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, 530 parts of deionized water was charged. In a dropping funnel, 113 parts of deionized water, 45 parts of a 25% aqueous solution of an emulsifier [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10], 65 parts of 2-ethylhexyl acrylate, 100 parts of cyclohexyl methacrylate, methyl methacrylate A pre-emulsion for dripping consisting of 80 parts and 5 parts of methacrylic acid is prepared, of which 80 parts, which is 5% of the total amount of all polymerizable monomer components, are added to the flask and up to 70 ° C. while gently blowing nitrogen gas. The temperature was raised, and 14 parts of a 5% aqueous ammonium persulfate solution was added to initiate polymerization. Next, the remainder of the pre-emulsion for dropping, 21.5 parts of 5% aqueous ammonium persulfate solution and 15 parts of 2.5% aqueous sodium hydrogen sulfite solution were added dropwise into the flask uniformly over 90 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 70 ° C. for 60 minutes. Subsequently, 225 parts of deionized water and a 25% aqueous solution of emulsifier [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10] 90 A second pre-emulsion consisting of 5 parts by weight, 100 parts of butyl acrylate, 150 parts of 2-ethylhexyl acrylate, 190 parts of cyclohexyl methacrylate, 50 parts of tert-butyl methacrylate, 5 parts of ethylene glycol dimethacrylate and 5 parts of acrylic acid. A 43% aqueous solution of ammonium persulfate and 30 parts of a 2.5% aqueous solution of sodium hydrogen sulfite were uniformly dropped into the flask over 180 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 70 ° C. for 60 minutes. Subsequently, 113 parts of deionized water and a 25% aqueous solution of emulsifier [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10] 45 3 parts pre-emulsion consisting of 5 parts 2-ethylhexyl acrylate, 200 parts cyclohexyl methacrylate, 40 parts methyl methacrylate and 5 parts acrylic acid, 21.5 parts of 5% aqueous ammonium persulfate solution and 2.5% sulfurous acid 15 parts of an aqueous sodium hydride solution was uniformly dropped into the flask over 90 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 70 ° 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. The content of non-volatile components in the obtained resin emulsion was 45%.

  The glass transition temperature of the polymer in the inner layer of the emulsion particles contained in the resin emulsion obtained above is 30 ° C., the glass transition temperature of the polymer in the intermediate layer is −10 ° C., and the polymer in the outer layer The glass transition temperature was 80 ° C., and the glass transition temperature of the entire emulsion particles was 19 ° C. Further, the content of the inner layer in the emulsion particles was 25%, the content of the intermediate layer was 50%, and the content of the outer layer was 25%. In addition, the content rate of each layer of an inner layer, an intermediate | middle layer, and an outer layer in an emulsion particle | grain is a value calculated | required based on the preparation ratio of the monomer component which comprises each layer (same in a following example and a comparative example).

Example 2
In a flask equipped with a dropping funnel, a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, 530 parts of deionized water was charged. In a dropping funnel, 150 parts of deionized water, 60 parts of a 25% aqueous solution of an emulsifier [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10], 20 parts of 2-ethylhexyl acrylate, 240 parts of cyclohexyl methacrylate, methyl methacrylate A pre-emulsion for dropping consisting of 75 parts and 5 parts of methacrylic acid was prepared, of which 80 parts corresponding to 5% of the total amount of all the polymerizable monomer components were added to the flask, and slowly blown with nitrogen gas up to 70 ° C. The temperature was raised, and 14 parts of a 5% aqueous ammonium persulfate solution was added to initiate polymerization. Next, the remainder of the pre-emulsion for dropping, 29 parts of 5% ammonium persulfate aqueous solution and 20 parts of 2.5% aqueous sodium hydrogen sulfite solution were added dropwise into the flask uniformly over 120 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 70 ° C. for 60 minutes. Subsequently, 150 parts of deionized water and a 25% aqueous solution of emulsifier [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10] 60 A second pre-emulsion consisting of 155 parts of 2-ethylhexyl acrylate, 170 parts of cyclohexyl methacrylate and 5 parts of acrylic acid, and 29 parts of 5% aqueous ammonium persulfate solution and 20 parts of 2.5% aqueous sodium hydrogen sulfite solution. It was dripped uniformly into the flask over 120 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 70 ° C. for 60 minutes. Subsequently, 150 parts of deionized water and a 25% aqueous solution of emulsifier [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10] 60 A third pre-emulsion consisting of 50 parts of 2-ethylhexyl acrylate, 195 parts of cyclohexyl methacrylate, 50 parts of methyl methacrylate and 5 parts of acrylic acid, 29 parts of 5% aqueous ammonium persulfate solution and 2.5% sodium bisulfite 20 parts of the aqueous solution was uniformly dropped into the flask over 120 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 70 ° 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. The content of non-volatile components in the obtained resin emulsion was 45%.

  The glass transition temperature of the polymer in the inner layer of the emulsion particles contained in the resin emulsion obtained above is 80 ° C., the glass transition temperature of the polymer in the intermediate layer is −10 ° C., and the polymer in the outer layer The glass transition temperature was 30 ° C., and the glass transition temperature of the entire emulsion particles was 28 ° C. The content of the inner layer in the emulsion particles was 34%, the content of the intermediate layer was 33%, and the content of the outer layer was 33%.

Example 3
In a flask equipped with a dropping funnel, a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, 530 parts of deionized water was charged. In a dropping funnel, 113 parts of deionized water, 45 parts of a 25% aqueous solution of an emulsifier (Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10), 5 parts of 2-ethylhexyl acrylate, 200 parts of cyclohexyl methacrylate and 45 of styrene A pre-emulsion for dripping consisting of parts is prepared, of which 80 parts, which is 5% of the total amount of all polymerizable monomer components, are added to the flask, and the temperature is raised to 70 ° C. while gently blowing nitrogen gas, and 5% 14 parts of an aqueous ammonium persulfate solution was added to initiate polymerization. Next, the remainder of the pre-emulsion for dropping, 21.5 parts of 5% aqueous ammonium persulfate solution and 15 parts of 2.5% aqueous sodium hydrogen sulfite solution were added dropwise into the flask uniformly over 90 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 70 ° C. for 60 minutes. Subsequently, 225 parts of deionized water and a 25% aqueous solution of emulsifier [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10] 90 Part, 100 parts of butyl acrylate, 150 parts of 2-ethylhexyl acrylate, 190 parts of cyclohexyl methacrylate, 50 parts of tert-butyl methacrylate, 5 parts of hydroxyethyl methacrylate and 5 parts of ethylene glycol dimethacrylate, 43 parts of a 5% aqueous solution of ammonium persulfate and 30 parts of a 2.5% aqueous solution of sodium hydrogen sulfite were uniformly dropped into the flask over 180 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 70 ° C. for 60 minutes. Subsequently, 113 parts of deionized water and a 25% aqueous solution of emulsifier [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10] 45 A third pre-emulsion consisting of 5 parts 2-ethylhexyl acrylate, 200 parts cyclohexyl methacrylate, 35 parts methyl methacrylate and 10 parts 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine, 21.5 parts of a% ammonium persulfate aqueous solution and 15 parts of a 2.5% sodium hydrogen sulfite 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 70 ° 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. The content of non-volatile components in the obtained resin emulsion was 45%.

  The glass transition temperature of the polymer in the inner layer of the emulsion particles contained in the resin emulsion obtained above is 80 ° C., the glass transition temperature of the polymer in the intermediate layer is −10 ° C., and the polymer in the outer layer The glass transition temperature was 80 ° C., and the glass transition temperature of the whole emulsion particle was 30 ° C. Further, the content of the inner layer in the emulsion particles was 25%, the content of the intermediate layer was 50%, and the content of the outer layer was 25%.

Example 4
In a flask equipped with a dropping funnel, a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, 530 parts of deionized water was charged. In a dropping funnel, 225 parts of deionized water, 90 parts of a 25% aqueous solution of an emulsifier [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10], 90 parts of 2-ethylhexyl acrylate, 150 parts of cyclohexyl methacrylate, methyl methacrylate A pre-emulsion for dripping consisting of 100 parts, 100 parts of tert-butyl methacrylate, 50 parts of styrene and 10 parts of methacrylic acid was prepared, and 80 parts corresponding to 5% of the total amount of all polymerizable monomer components were added to the flask. The temperature was raised to 70 ° C. while gently blowing nitrogen gas, and 14 parts of a 5% ammonium persulfate aqueous solution was added to initiate polymerization. Next, the remainder of the dropping pre-emulsion, 43 parts of 5% ammonium persulfate aqueous solution and 30 parts of 2.5% aqueous sodium hydrogen sulfite solution were added dropwise into the flask uniformly over 180 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 70 ° C. for 60 minutes. Subsequently, 113 parts of deionized water and a 25% aqueous solution of emulsifier [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10] 45 Part, 2-ethylhexyl acrylate 135 parts, n-butyl methacrylate 65 parts and cyclohexyl methacrylate 50 parts, a 2nd stage pre-emulsion was prepared, 5% ammonium persulfate aqueous solution 21.5 parts and 2.5% sodium hydrogen sulfite aqueous solution 15 parts were uniformly dropped into the flask over 90 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 70 ° C. for 60 minutes. Subsequently, 113 parts of deionized water and a 25% aqueous solution of emulsifier [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10] 45 Part, 2-ethylhexyl acrylate 90 parts, cyclohexyl methacrylate 500 parts, n-butyl methacrylate 90 parts and hydroxyethyl methacrylate 20 parts, and a 5% ammonium persulfate aqueous solution 21.5 parts and 2. 15 parts of 5% aqueous sodium hydrogen sulfite solution was added dropwise into the flask uniformly over 90 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 70 ° 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. The content of non-volatile components in the obtained resin emulsion was 45%.

  The glass transition temperature of the polymer in the inner layer of the emulsion particles contained in the resin emulsion obtained above is 50 ° C., the glass transition temperature of the polymer in the intermediate layer is −30 ° C., and the polymer in the outer layer The glass transition temperature was −10 ° C., and the glass transition temperature of the entire emulsion particles was 10 ° C. The content of the inner layer in the emulsion particles was 50%, the content of the intermediate layer was 25%, and the content of the outer layer was 25%.

Example 5
In a flask equipped with a dropping funnel, a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, 530 parts of deionized water was charged. In a dropping funnel, 113 parts of deionized water, 45 parts of a 25% aqueous solution of an emulsifier [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10], 5 parts of 2-ethylhexyl acrylate, 200 parts of cyclohexyl methacrylate, methyl methacrylate A pre-emulsion for dripping consisting of 20 parts, 20 parts of styrene and 5 parts of methacrylic acid was prepared, 80 parts corresponding to 5% of the total amount of all polymerizable monomer components were added into the flask, and nitrogen gas was gently blown into the flask. While raising the temperature to 70 ° C., 14 parts of a 5% aqueous solution of ammonium persulfate was added to initiate polymerization. Next, the remainder of the pre-emulsion for dropping, 21.5 parts of 5% aqueous ammonium persulfate solution and 15 parts of 2.5% aqueous sodium hydrogen sulfite solution were added dropwise into the flask uniformly over 90 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 70 ° C. for 60 minutes. Subsequently, 225 parts of deionized water and a 25% aqueous solution of emulsifier [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10] 90 A second pre-emulsion consisting of 100 parts of 2-ethylhexyl acrylate, 245 parts of n-butyl methacrylate, 150 parts of cyclohexyl methacrylate and 5 parts of acrylic acid was prepared, 43 parts of 5% ammonium persulfate aqueous solution and 2.5% sulfurous acid. 30 parts of an aqueous sodium hydride solution was uniformly dropped into the flask over 180 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 70 ° C. for 60 minutes. Subsequently, 113 parts of deionized water and a 25% aqueous solution of emulsifier [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10] 45 3 parts of pre-emulsion consisting of 65 parts of 2-ethylhexyl acrylate, 100 parts of cyclohexyl methacrylate, 80 parts of methyl methacrylate and 5 parts of acrylic acid, 21.5 parts of 5% ammonium persulfate aqueous solution and 2.5% sulfurous acid 15 parts of an aqueous sodium hydride solution was uniformly dropped into the flask over 90 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 70 ° 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. The content of non-volatile components in the obtained resin emulsion was 45%.

  The glass transition temperature of the inner layer polymer of the emulsion particles contained in the resin emulsion obtained above is 80 ° C., the glass transition temperature of the intermediate layer polymer is 10 ° C., and the outer layer polymer glass. The transition temperature was 30 ° C., and the glass transition temperature of the whole emulsion particle was 30 ° C. Further, the content of the inner layer in the emulsion particles was 25%, the content of the intermediate layer was 50%, and the content of the outer layer was 25%.

Example 6
In a flask equipped with a dropping funnel, a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, 530 parts of deionized water was charged. In a dropping funnel, 150 parts of deionized water, 60 parts of a 25% aqueous solution of an emulsifier [manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10], 260 parts of cyclohexyl methacrylate, 70 parts of isobornyl methacrylate and methacrylic acid A pre-emulsion for dripping consisting of 5 parts was prepared, 80 parts corresponding to 5% of the total amount of all polymerizable monomer components were added to the flask, and the temperature was raised to 70 ° C. while gently blowing nitrogen gas. Polymerization was started by adding 14 parts of an aqueous ammonium persulfate solution. Next, the remainder of the pre-emulsion for dropping, 29 parts of 5% ammonium persulfate aqueous solution and 20 parts of 2.5% aqueous sodium hydrogen sulfite solution were added dropwise into the flask uniformly over 120 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 70 ° C. for 60 minutes. Subsequently, 150 parts of deionized water and a 25% aqueous solution of emulsifier [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10] 60 2 parts pre-emulsion consisting of 1 part, 2-ethylhexyl acrylate 260 parts, cyclohexyl methacrylate 50 parts, γ-methacryloyloxypropyltrimethoxysilane 10 parts and acrylic acid 10 parts, and 29 parts 5% aqueous ammonium persulfate and 2 parts 20 parts of a 5% aqueous sodium hydrogen sulfite solution was uniformly dropped into the flask over 120 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 70 ° C. for 60 minutes. Subsequently, 150 parts of deionized water and a 25% aqueous solution of emulsifier [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10] 60 A third pre-emulsion consisting of 10 parts of cyclohexyl methacrylate, 160 parts of cyclohexyl acrylate and 10 parts of 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine, and 29 parts of 5% aqueous ammonium persulfate solution, 20 parts of a 2.5% aqueous sodium hydrogen sulfite solution was added dropwise into the flask uniformly over 120 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 70 ° 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. The content of non-volatile components in the obtained resin emulsion was 45%.

  The glass transition temperature of the polymer in the inner layer of the emulsion particles contained in the resin emulsion obtained above is 100 ° C., the glass transition temperature of the polymer in the intermediate layer is −50 ° C., and the polymer in the outer layer The glass transition temperature was 50 ° C., and the glass transition temperature of the entire emulsion particles was 21 ° C. The content of the inner layer in the emulsion particles was 34%, the content of the intermediate layer was 33%, and the content of the outer layer was 33%.

Comparative Example 1
In a flask equipped with a dropping funnel, a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, 530 parts of deionized water was charged. In a dropping funnel, 225 parts of deionized water, 90 parts of a 25% aqueous solution of an emulsifier [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10], 140 parts of 2-ethylhexyl acrylate, 50 parts of cyclohexyl methacrylate, methyl methacrylate Prepare a pre-emulsion for dripping consisting of 250 parts, 50 parts of styrene and 10 parts of methacrylic acid, of which 80 parts, which is 5% of the total amount of all polymerizable monomer components, are added to the flask and gently blown with nitrogen gas. While raising the temperature to 70 ° C., 14 parts of a 5% aqueous solution of ammonium persulfate was added to initiate polymerization. Next, the remainder of the dropping pre-emulsion, 43 parts of 5% ammonium persulfate aqueous solution and 30 parts of 2.5% aqueous sodium hydrogen sulfite solution were added dropwise into the flask uniformly over 180 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 70 ° C. for 60 minutes. Subsequently, 225 parts of deionized water and a 25% aqueous solution of emulsifier [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10] 90 A second pre-emulsion consisting of 50 parts of 2-ethylhexyl acrylate, 50 parts of cyclohexyl methacrylate, 400 parts of methyl methacrylate and 10 parts of acrylic acid, 43 parts of 5% aqueous ammonium persulfate solution and 2.5% sodium hydrogen sulfite 30 parts of the aqueous solution was uniformly dropped into the flask over 180 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 70 ° 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. The content of non-volatile components in the obtained resin emulsion was 45%.

  The glass transition temperature of the polymer of the inner layer of the emulsion particles contained in the resin emulsion obtained above is 30 ° C., the glass transition temperature of the polymer of the outer layer is 80 ° C., and the glass transition temperature of the whole emulsion particles. Was 52 ° C. Further, the content of the inner layer in the emulsion particles was 50%, and the content of the outer layer was 50%.

Comparative Example 2
In a flask equipped with a dropping funnel, a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, 530 parts of deionized water was charged. In a dropping funnel, 225 parts of deionized water, 90 parts of a 25% aqueous solution of an emulsifier [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10], 40 parts of 2-ethylhexyl acrylate, 50 parts of cyclohexyl methacrylate, methyl methacrylate A pre-emulsion for dripping consisting of 400 parts and 10 parts of methacrylic acid is prepared, of which 80 parts, which is 5% of the total amount of all polymerizable monomer components, are added to the flask and up to 70 ° C. while gently blowing nitrogen gas. The temperature was raised, and 14 parts of a 5% aqueous ammonium persulfate solution was added to initiate polymerization. Next, the remainder of the dropping pre-emulsion, 43 parts of 5% ammonium persulfate aqueous solution and 30 parts of 2.5% sodium hydrogen sulfite aqueous solution were uniformly dropped into the flask over 180 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 70 ° C. for 60 minutes. Subsequently, 225 parts of deionized water and a 25% aqueous solution of emulsifier [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Aqualon BC-10] 90 A second pre-emulsion consisting of 140 parts of 2-ethylhexyl acrylate, 50 parts of cyclohexyl methacrylate, 300 parts of methyl methacrylate and 10 parts of acrylic acid, 43 parts of 5% aqueous ammonium persulfate solution and 2.5% sodium bisulfite 30 parts of the aqueous solution was uniformly dropped into the flask over 180 minutes.

  After completion of the dropwise addition, the contents of the flask were maintained at 70 ° 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. The content of non-volatile components in the obtained resin emulsion was 45%.

  The glass transition temperature of the polymer in the inner layer of the emulsion particles contained in the resin emulsion obtained above is 80 ° C., the glass transition temperature of the polymer in the outer layer is 30 ° C., and the glass transition temperature of the whole emulsion particles. Was 53 ° C. Further, the content of the inner layer in the emulsion particles was 50%, and the content of the outer layer was 50%.

Experimental Example 2,2,4-Trimethyl-1,3-pentanediol mono as a film forming aid while dispersing the resin emulsion obtained in each example or each comparative example with a homodisper at a rotational speed of 1500 min ⁻¹ . A mixed solution obtained by mixing isobutyrate [manufactured by Chisso Corporation, product number: CS-12] and butyl cellosolve at an equal weight is added so that the minimum film-forming temperature of the resin emulsion is 5 ° C. After the adjustment, the content of the non-volatile component was adjusted to 30% by adding dilution water and a foam suppressor [manufactured by San Nopco Co., Ltd., trade name: SN deformer 777].

A matting agent [manufactured by Nippon Shokubai Co., Ltd., trade name: Eposta MA1010] was added to the mixture at a ratio of 8.8 parts per 100 parts of the obtained mixture, and a Craves unit viscometer (manufactured by Brookfield, Thickener [manufactured by Nippon Shokubai Co., Ltd., trade name: AKRESET WR-503A] was added to the mixture so that the viscosity when measured at 25 ° C. using product number: KU-1) was 65 ± 1 KU. Then, this mixture was dispersed with a homodisper at a rotational speed of 1500 min ^{-1 for} 30 minutes to obtain a clear coating. The obtained clear paint was allowed to stand at room temperature for 1 day, and the following physical properties were examined. The results are shown in Table 1. In addition, a thing with one evaluation of "x" in a physical property is determined to be disqualified.

(1) Water resistance According to JIS K6717 (2006), a black acrylic plate obtained by molding methyl methacrylate by extrusion molding (manufactured by Nippon Test Panel Co., Ltd., length: 75 mm, width: 150 mm, thickness: 3 mm], the clear paint obtained above was applied with a 5 mil applicator and dried in a hot air dryer at 100 ° C. for 10 minutes to prepare a test plate.

After the obtained test plate was cured at 23 ° C. for 24 hours, the L value (L ₀ ) of the test plate was measured using a color difference meter [manufactured by Nippon Denshoku Industries Co., Ltd., trade name: spectroscopic color difference meter SE-2000]. The test plate was further immersed in warm water adjusted to 60 ° C. for 240 hours, then pulled up from the warm water, wiped with Kim Towel (manufactured by Nippon Paper Crecia Co., Ltd.), and within 1 minute. The L value (L ₁ ) was measured with a color difference meter.

Next, the change value of the L value is expressed by the formula:
ΔL = (L ₁ ) − (L ₀ )
The water resistance was evaluated based on the following evaluation criteria.
〔Evaluation criteria〕
A: ΔL is less than 2.0 ○: ΔL is 2.0 or more and less than 4.0 Δ: ΔL is 4.0 or more and less than 6.0 ×: ΔL is 6.0 or more

(2) Water permeability resistance A test plate was prepared in the same manner as described in the above "Water resistance". After sealing the back and side surfaces of the test plate with a bath bond [manufactured by Konishi Co., Ltd., trade name: bus bond Q], and submerging the test plate in water at room temperature (about 25 ° C.) for 24 hours, It took out from water, wiped off moisture sufficiently, measured a mass difference before and after submergence of the test plate, and evaluated based on the following evaluation criteria.
(Evaluation criteria)
○: Mass difference before and after submersion of test specimen is less than 2 g Δ: Mass difference before and after submersion of test specimen is 2 g or more and less than 5 g ×: Mass difference before and after submersion of test specimen is 5 g or more

(3) Low-temperature film-formability After applying a clear coating with a 20 mil applicator to a float glass plate (manufactured by Nippon Test Panel Co., Ltd., length: 70 mm, width: 150 mm, thickness: 2 mm), the float glass plate was placed at 5 ° C. The film was dried for 24 hours in a thermostatic box whose temperature was adjusted to a thickness of approximately 150 μm after drying. The state of the coating film after drying was observed using a 30-fold magnifier, and the low-temperature film forming property was evaluated based on the following evaluation criteria.
(Evaluation criteria)
○: No crack Δ: A small crack (a crack having a length of less than 5 mm) is observed in the coating film.
X: A large crack (a crack having a length of 5 mm or more) is observed in the coating film.

(4) Stretchability A clear coating was applied to a polypropylene plate (length: 70 mm, width: 150 mm, thickness: 2 mm) with a 20 mil applicator, dried at room temperature for 24 hours, and then formed coating (length: about 1 cm) , Width: about 7 cm, thickness: 150 μm) was peeled from the polypropylene plate.

Next, the temperature of the peeled coating film was adjusted for 3 hours in a thermostatic box adjusted to 0 ° C., and then the short side of the coating film was pulled by a tensile tester [manufactured by Shimadzu Corporation, trade name: Autograph AGS. −100D] chuck and pulling under the conditions of an initial marked line distance of 50 mm and a pulling speed of 200 mm / min.
[Elongation rate (%)] = [(Elongation at break−50 mm) ÷ (50 mm)] × 100
Based on the above, the elongation rate of the coating film was examined, and the extensibility was evaluated based on the following evaluation criteria.
(Evaluation criteria)
○: Elongation rate is 30% or more Δ: Elongation rate is 20% or more and less than 30% ×: Elongation rate is less than 20%

(5) Heat-resistant deformation According to JIS R3202 (1996), the clear paint obtained above was applied to a float glass plate (manufactured by Nippon Test Panel Co., Ltd., 70 mm long, 150 mm wide, 2 mm thick) with a 5 mil applicator. The test plate was produced by applying and drying with a hot air dryer at 100 ° C. for 10 minutes.

Immediately move the obtained test plate into a hot air dryer at 60 ° C., adjust the temperature for 1 minute, and then apply gauze [manufactured by Hyoe Sanitary Materials Co., Ltd., Japanese Pharmacopoeia Gauze Type 1], float glass on the test plate. A board (manufactured by Nippon Test Panel Co., Ltd., 70 mm in length, 150 mm in width, 2 mm in thickness) and a weight were loaded in this order and left at a temperature of 60 ° C. for 2 hours. At this time, the load was adjusted to be 280 g / cm ² .

Next, after cooling the test plate to room temperature, the gauze on the test plate was slowly peeled off, the state of the coating film was visually observed, and the heat deformation resistance was evaluated based on the following evaluation criteria.
〔Evaluation criteria〕
A: No abnormality (no gauze marks)
○: Slight gauze traces △: Shallow gauze traces ×: Deep gauze traces

  Next, in the evaluation of the above physical properties, total evaluation was performed by summing up the scores of each physical property, with ◎ being 20 points, ○ being 15 points, Δ being 10 points, and × being 0 points. In addition, the highest score of comprehensive evaluation is 100, and the lowest score is 0 points. The results are also shown in Table 1.

  From the results shown in Table 1, each of the resin emulsions obtained in each example has a coating film that is comprehensively excellent in water resistance, water permeability, low temperature film formability, stretchability, and heat distortion resistance. It turns out that it forms. Further, from the comparison result between Example 1 and Comparative Example 1, in Example 1, an intermediate layer having a glass transition temperature lower than that of the inner layer and the outer layer is formed between the inner layer and the outer layer. In contrast, it can be seen that the water resistance, water permeability resistance, low-temperature film-forming property and extensibility are excellent. Furthermore, from the comparison result between Example 2 and Comparative Example 2, in Example 2, an intermediate layer having a glass transition temperature lower than that of the inner layer and the outer layer is formed between the inner layer and the outer layer. In contrast, it can be seen that it is excellent in water permeability, low-temperature film-forming properties, extensibility, and heat distortion resistance.

  The resin emulsion of the present invention is expected to be used in, for example, water-based paints coated on the exterior of buildings, ceramic building materials, and the like.

Claims (4)

  A polymer emulsion comprising emulsion particles having at least three resin layers of an inner layer, an intermediate layer and an outer layer, wherein the polymer constituting the intermediate layer has a glass transition temperature constituting a layer other than the intermediate layer A resin emulsion characterized by being 10 ° C. or more lower than any glass transition temperature.   The resin emulsion according to claim 1, wherein the polymer constituting the outer layer has a glass transition temperature of 0 ° C. or higher.   The resin emulsion according to claim 1 or 2, wherein the content of the outer layer in the emulsion particles is 10 to 50% by mass.   An aqueous paint comprising the resin emulsion according to any one of claims 1 to 3.