Surfactant composition, composition for emulsion polymerization, method for producing polymer emulsion, and polymer emulsion

Abstract

To provide a surfactant composition from which a polymer emulsion excellent in adhesive characteristics, mechanical stability, and water resistance can be obtained.SOLUTION: The present invention provides the surfactant composition containing 95.5-99.2 mass% of an anionic surfactant represented by the following general formula (1) and 0.8-4.5 mass% of a nonionic surfactant represented by the following general formula (2). (In formula (1), R1 represents a C8-15 linear or branched alkyl group; m represents a number of 5-50; and M represents a hydrogen atom, an alkali metal atom or an ammonium group.) (In formula (2), R2 represents a C8-15 linear or branched alkyl group; and n represents a number of 5-50.)SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a surfactant composition which can provide a polymer emulsion having excellent adhesive properties, mechanical stability, and water resistance. [Background technology]

[0002] Resin emulsions of acrylic resins, styrene resins, etc. are used in paints, adhesives, pressure sensitive adhesives, coating agents, inks, cement, mortar, car wax, etc. In order to improve various properties of the resin emulsions, a method is known in which a reactive emulsifier is used when producing the resin emulsion by emulsion polymerization of raw material monomers, and various reactive emulsifiers have been proposed so far.

[0003] Known reactive emulsifiers include, for example, various reactive emulsifiers having a (meth)allyl ether group as a reactive group (Patent Documents 1 and 2) and various reactive emulsifiers having a (meth)acrylic acid ester group as a reactive group (Patent Documents 3 and 4). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 63-054927 [Patent Document 2] Japanese Patent Application Publication No. 63-319035 [Patent Document 3] Japanese Patent Application Publication No. 63-077530 [Patent Document 4] Japanese Patent Application Publication No. 63-185436 DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0005] However, the reactive emulsifiers described in Patent Documents 1 to 4 do not provide sufficient adhesive properties, mechanical stability, and water resistance to the resulting polymer emulsions, and there is still a demand in the market for surfactant compositions having superior properties.

[0006] Therefore, an object of the present invention is to provide a surfactant composition which can give a polymer emulsion having excellent adhesive properties, mechanical stability, and water resistance. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above problems, and have found that a surfactant composition containing specific amounts of a specific anionic surfactant and a specific nonionic surfactant can provide a polymer emulsion excellent in adhesion properties, mechanical stability, and water resistance, thereby completing the present invention. That is, the present invention is a surfactant composition containing 95.5% by mass to 99.2% by mass of an anionic surfactant represented by the following general formula (1) and 0.8% by mass to 4.5% by mass of a nonionic surfactant represented by the following general formula (2).

[0008] [ka]

[0009] (In the formula, R 1 represents an alkyl group having 8 to 15 carbon atoms, m represents a number from 5 to 50, and M represents a hydrogen atom, an alkali metal atom, or an ammonium group.

[0010] [ka]

[0011] (In the formula, R 2 represents an alkyl group having 8 to 15 carbon atoms, and n represents a number from 5 to 50. Effect of the Invention

[0012] By using the surfactant composition according to the present invention, a polymer emulsion having excellent adhesive properties, mechanical stability, and water resistance can be prepared. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] A. Anionic surfactants The anionic surfactant used in the present invention is an anionic surfactant represented by the following general formula (1).

[0014] [ka]

[0015] R in general formula (1) 1 represents an alkyl group having 8 to 15 carbon atoms, and examples of such groups include linear or branched alkyl groups such as octyl, branched octyl, nonyl, branched nonyl, decyl, branched decyl, undecyl, branched undecyl, dodecyl, branched dodecyl, tridecyl, branched tridecyl, tetradecyl, branched tetradecyl, pentadecyl, and branched pentadecyl. Among these, from the viewpoint of obtaining a surfactant composition that can give a polymer emulsion having better adhesion properties, mechanical stability, and water resistance, R in general formula (1) is 1 is preferably a linear or branched alkyl group having 10 to 15 carbon atoms, and more preferably a linear or branched alkyl group having 11 to 13 carbon atoms. From the viewpoint of obtaining a surfactant composition that can give a polymer emulsion having better adhesion properties, mechanical stability, and water resistance, R in general formula (1) is 1 is preferably a branched alkyl group, and more preferably an isoalkyl group, which is a branched alkyl group having three or more terminal methyl groups. In the present invention, from the viewpoint of obtaining a surfactant composition capable of obtaining a polymer emulsion having excellent adhesion properties, mechanical stability, and water resistance, among these, R in general formula (1) is 1is preferably an isoalkyl group having 10 to 15 carbon atoms, more preferably an isoalkyl group having 11 to 13 carbon atoms, and particularly preferably an isoundecyl group.

[0016] In general formula (1), m represents a number from 5 to 50. Among these, from the viewpoint of obtaining a surfactant composition from which a polymer emulsion having more excellent adhesion properties, mechanical stability, and water resistance can be obtained, m in general formula (1) is preferably 10 to 40, and more preferably 10 to 30. From the viewpoint of obtaining a surfactant composition which can provide a polymer emulsion having superior adhesion properties, mechanical stability, and water resistance, the average value of m is preferably from 7 to 45, more preferably from 8 to 40, and even more preferably from 10 to 30.

[0017] M in the general formula (1) represents a hydrogen atom, an alkali metal atom, or an ammonium group, and examples of the alkali metal atom include a lithium atom, a sodium atom, a potassium atom, etc. Among these, from the viewpoint of obtaining a surfactant composition that can give a polymer emulsion having better adhesion properties, mechanical stability, and water resistance, M in the general formula (1) is preferably a hydrogen atom, a sodium atom, a potassium atom, or an ammonium group, and more preferably an ammonium group.

[0018] The method for producing the anionic surfactant represented by general formula (1) is not particularly limited, and the surfactant can be produced by a known method, for example, the method described in JP-A-2006-075808.

[0019] B. Nonionic surfactants The nonionic surfactant used in the present invention is an anionic surfactant represented by the following general formula (2).

[0020] [ka]

[0021] R in general formula (2) 2 represents an alkyl group having 8 to 15 carbon atoms, and examples of such groups include linear or branched alkyl groups such as octyl group, branched octyl group, nonyl group, branched nonyl group, decyl group, branched decyl group, undecyl group, branched undecyl group, dodecyl group, branched dodecyl group, tridecyl group, branched tridecyl group, tetradecyl group, branched tetradecyl group, pentadecyl group, branched pentadecyl group, hexadecyl group, branched hexadecyl group, heptadecyl group, branched heptadecyl group, stearyl group, branched stearyl group, eicosyl group, and branched eicosyl group. Among these, from the viewpoint of obtaining a surfactant composition that can obtain a polymer emulsion having better adhesion properties, mechanical stability, and water resistance, R in general formula (2) is 2 is preferably a linear or branched alkyl group having 10 to 15 carbon atoms, and more preferably a linear or branched alkyl group having 11 to 13 carbon atoms. From the viewpoint of obtaining a surfactant composition that can give a polymer emulsion having better adhesion properties, mechanical stability, and water resistance, R in general formula (2) is 2 is preferably a branched alkyl group, and more preferably an isoalkyl group, which is a branched alkyl group having three or more terminal methyl groups. In the present invention, from the viewpoint of obtaining a surfactant composition capable of obtaining a polymer emulsion having excellent adhesion properties, mechanical stability, and water resistance, among these, R in general formula (2) is 2 is preferably an isoalkyl group having 10 to 15 carbon atoms, more preferably an isoalkyl group having 11 to 13 carbon atoms, and particularly preferably an isoundecyl group.

[0022] In general formula (2), n represents a number from 5 to 50. Among these, from the viewpoint of obtaining a surfactant composition from which a polymer emulsion having more excellent adhesion properties, mechanical stability, and water resistance can be obtained, n in general formula (1) is preferably 10 to 40, and more preferably 10 to 30. The average value of n is preferably from 7 to 45, more preferably from 8 to 40, and even more preferably from 10 to 30, from the viewpoint of obtaining a surfactant composition which can give a polymer emulsion having better adhesion properties, mechanical stability, and water resistance.

[0023] The method for producing the nonionic surfactant represented by general formula (2) is not particularly limited, and the surfactant can be produced by known methods, for example, the method described in JP-A-2002-301353.

[0024] C. Surfactant Composition The surfactant composition of the present invention is a surfactant composition containing 95.5% by mass to 99.2% by mass of the anionic surfactant represented by the above-mentioned general formula (1) and 0.8% by mass to 4.5% by mass of the nonionic surfactant represented by the above-mentioned general formula (2) based on the total amount of the surfactant composition. If the content of the anionic surfactant represented by the general formula (1) is less than 95.5% by mass, the polymer emulsion may have poor adhesion properties and water resistance when used in emulsion polymerization, and if it is more than 99.2% by mass, the polymer emulsion may have poor adhesion properties and mechanical stability when used in emulsion polymerization. Similarly, if the content of the nonionic surfactant represented by the general formula (2) is less than 0.8% by mass, the polymer emulsion may have poor adhesion properties and mechanical stability when used in emulsion polymerization, and if it is more than 4.5% by mass, the polymer emulsion may have poor adhesion properties and water resistance when used in emulsion polymerization. In the present invention, from the viewpoint of obtaining a surfactant composition that can give a polymer emulsion having better adhesion properties, mechanical stability, and water resistance, the surfactant composition of the present invention preferably contains 95.8% by mass to 99.1% by mass of the anionic surfactant represented by general formula (1) and 0.9% by mass to 4.2% by mass of the nonionic surfactant represented by general formula (2), and more preferably contains 96.0% by mass to 99.0% by mass of the anionic surfactant represented by general formula (1) and 1.0% by mass to 4.0% by mass of the nonionic surfactant represented by general formula (2).

[0025] In the surfactant composition of the present invention, the anionic surfactant represented by the above-mentioned general formula (1) and the nonionic surfactant represented by the above-mentioned general formula (2) may contain other components (for example, various components described later) within the scope of not impairing the effects of the present invention, but from the viewpoint of easily obtaining a polymer emulsion excellent in adhesion properties, mechanical stability, and water resistance, the total content of the anionic surfactant represented by the general formula (1) and the nonionic surfactant represented by the general formula (2) in the surfactant composition is preferably 96.5% by mass or more, more preferably 97.0% by mass or more, even more preferably 99.0% by mass or more, and particularly preferably 100% by mass, based on the total amount of the surfactant composition. In other words, it is particularly preferable that the surfactant composition of the present invention is composed of the anionic surfactant represented by the above-mentioned general formula (1) and the nonionic surfactant represented by the above-mentioned general formula (2), except for inevitable impurities.

[0026] In the present invention, from the viewpoint of obtaining a surfactant composition capable of obtaining a polymer emulsion having superior adhesion properties, mechanical stability, and water resistance, the alkyl group R of the anionic surfactant represented by the general formula (1) is 1 and an alkyl group R of a nonionic surfactant represented by general formula (2): 2 Specifically, for example, the surfactant composition of the present invention may be a surfactant having a structure represented by the general formula (1) in which R 1 is an alkyl group having 8 to 15 carbon atoms, and 95.5% by mass to 99.2% by mass of an anionic surfactant, 2 R 1 and 0.8% by mass to 4.5% by mass of a nonionic surfactant having the same alkyl group as that of R 1 is a linear or branched alkyl group having 11 to 13 carbon atoms, and 2 R 1and 0.8% by mass to 4.5% by mass of a nonionic surfactant having the same alkyl group as that of R 1 is an isoalkyl group having 11 to 13 carbon atoms, and 95.5% by mass to 99.2% by mass of an anionic surfactant represented by the general formula (2), R 2 R 1 and 0.8% by mass to 4.5% by mass of a nonionic surfactant having the same alkyl group as in the general formula (1), 1 is an isoalkyl group having 11 to 13 carbon atoms, and 96.0% by mass to 99.0% by mass of an anionic surfactant, 2 R 1 and 1.0 to 4.0 mass % of a nonionic surfactant having the same alkyl group as that of the surfactant.

[0027] In the present invention, the alkyl group R of the anionic surfactant represented by the general formula (1) 1 and an alkyl group R of a nonionic surfactant represented by general formula (2): 2 and are the same alkyl group, excluding unintended structures derived from trace components in the raw materials used in the production of each, the alkyl group R of the anionic surfactant represented by the general formula (1) 1 and an alkyl group R of a nonionic surfactant represented by general formula (2): 2 This indicates that the number of carbon atoms and the linear or branched structure thereof are substantially the same as those of the alkyl group R of the anionic surfactant represented by the general formula (1) in the surfactant composition. 1 In the case where the alkyl group R of the nonionic surfactant represented by the general formula (2) is 2 It is also shown that R 1 In the case where the composition contains two or more anionic surfactants represented by general formula (1) having different R 2It means that two or more nonionic surfactants represented by general formula (2) having different alkyl groups are contained in the same amount as the anionic surfactant represented by general formula (1) having the corresponding alkyl group structure. Here, "same amount" means that the difference in the content of both is within 5% by mass, preferably within 3% by mass, and more preferably within 1% by mass.

[0028] In the present invention, from the viewpoint of obtaining a surfactant composition that can produce a polymer emulsion having better adhesion properties, mechanical stability, and water resistance, it is preferable that the number m of added ethylene oxide groups in the anionic surfactant represented by general formula (1) is the same as the number n of added ethylene oxide groups in the nonionic surfactant represented by general formula (2). Specifically, for example, the surfactant composition of the present invention preferably contains 95.5% by mass to 99.2% by mass of an anionic surfactant in which m is a number of 5 to 50 in general formula (1) and 0.8 to 4.5% by mass of a nonionic surfactant in which n is the same number as m in general formula (2), and contains 95.5% by mass to 99.2% by mass of an anionic surfactant in which m is a number of 10 to 30 in general formula (1) and 0.8% by mass to 4.5% by mass of a nonionic surfactant in which n is the same number as m in general formula (2). more preferably, it contains 95.5% by mass to 99.2% by mass of an anionic surfactant in which m is 10, 20, or 30 in general formula (1) and 0.8% by mass to 4.5% by mass of a nonionic surfactant in which n is the same number as m in general formula (2), and even more preferably, it contains 96.0% by mass to 99.0% by mass of an anionic surfactant in which m is 10 or 30 in general formula (1) and 1.0% by mass to 4.0% by mass of a nonionic surfactant in which n is the same number as m in general formula (2).

[0029] In addition, the statement that the number m of added ethylene oxide groups in the anionic surfactant represented by general formula (1) and the number n of added ethylene oxide groups in the nonionic surfactant represented by general formula (2) are the same means that the values ​​of the number m of added ethylene oxide groups in the anionic surfactant represented by general formula (1) and the number n of added ethylene oxide groups in the nonionic surfactant represented by general formula (2), excluding unintended structures derived from by-products and the like during the production of each, are the same. This means that, for example, when the number m of added ethylene oxide groups of the anionic surfactant represented by general formula (1) in the surfactant composition is a specific number, the number n of added ethylene oxide groups of the nonionic surfactant represented by general formula (2) is also the same number, and when the surfactant composition contains two or more anionic surfactants represented by general formula (1) with different values ​​of m, the nonionic surfactant represented by general formula (2) also contains two or more nonionic surfactants represented by general formula (2) with different n in the amount equivalent to the content of the anionic surfactant represented by general formula (1) with the corresponding number of added ethylene oxide groups. Note that the "equivalent amount" is defined as above.

[0030] In addition, in the surfactant composition of the present invention, when the value of the number m of added ethylene oxide groups of the anionic surfactant represented by general formula (1) and the value of the number n of added ethylene oxide groups of the nonionic surfactant represented by general formula (2) are expressed by the average value of the number of added ethylene oxide groups of the anionic surfactant represented by general formula (1) contained in the surfactant composition and the average value of the number of added ethylene oxide groups of the nonionic surfactant represented by general formula (2), respectively, from the viewpoint of obtaining a surfactant composition that can obtain a polymer emulsion having better adhesion properties, mechanical stability, and water resistance, it is preferable that the average value of the number of added ethylene oxide groups of the anionic surfactant represented by general formula (1) contained in the surfactant composition of the present invention and the average value of the number of added ethylene oxide groups of the nonionic surfactant represented by general formula (2) are equivalent. Here, "equivalent average value" refers to the difference between the two values ​​being within 20% based on the average value of the number of added ethylene oxide groups of the anionic surfactant represented by general formula (1), preferably within 10%, more preferably within 5%.

[0031] The surfactant composition of the present invention can be used without any particular limitation in the usual applications of surfactants. For example, it can be used as a surfactant composition for emulsion polymerization, a surfactant composition for suspension polymerization, a surfactant composition for resin modification (improvement of water repellency, adjustment of hydrophilicity, improvement of compatibility, improvement of antistatic properties, improvement of antifogging properties, improvement of water resistance, improvement of adhesion, improvement of dyeability, improvement of film-forming properties, improvement of weather resistance, improvement of blocking resistance, etc.), a surfactant composition for fiber processing, a surfactant composition for fiber antifouling processing, etc. Among these, from the viewpoint of the effect of the present invention, it is preferable to use the surfactant composition of the present invention as a surfactant composition for emulsion polymerization. When the surfactant composition of the present invention is used as a surfactant composition for emulsion polymerization, its specific product field is not limited, and it can be used as a surfactant composition for emulsion polymerization for producing a polymer emulsion for use in, for example, paint, adhesive, pressure sensitive adhesive, ink, film, coating agent, paper coating agent, sizing agent, sealer, etc.

[0032] The polymerizable monomer that can be used when producing a polymer emulsion by using the surfactant composition of the present invention as a surfactant composition for emulsion polymerization is not particularly limited and can be appropriately selected depending on the purpose. For example, one or more types selected from the group consisting of acrylate-based monomers, styrene-based monomers, vinyl ester-based monomers, diene-based monomers, and acrylonitrile-based monomers can be used.

[0033] Examples of the acrylate monomers include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-nonyl acrylate, n-decyl acrylate, lauryl acrylate, stearyl acrylate, eicosanyl acrylate, behenyl acrylate, cyclohexyl acrylate, benzyl acrylate, tetracosanyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl meth ... Examples of the acrylates include butyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, n-nonyl methacrylate, n-decyl methacrylate, lauryl methacrylate, 2-methoxyethyl acrylate, 2-butoxyethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, diethylene glycol monoacrylate, polyethylene glycol monoacrylate, methoxytetraethylene glycol acrylate, methoxypolyethylene glycol acrylate, 2-(dimethylamino)ethyl acrylate, and acrylic acid. One or more of these may be used.

[0034] Examples of styrene-based monomers include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 2,4-dimethylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, methoxystyrene, 4-methoxy-3-methylstyrene, dimethoxystyrene, 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 4-bromostyrene, 2-methyl-4,6-dichlorostyrene, and 2,4-dibromostyrene. One or more of these may be used.

[0035] Examples of vinyl ester monomers include vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl versatate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl myristate, vinyl palmitate, vinyl stearate, vinyl oleate, and vinyl benzoate, and one or more of these can be used.

[0036] Examples of diene monomers include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 2,4-hexadiene, 1,3-octadiene, 2-methyl-1,3-pentadiene, 2,3-dimethyl-1,3-pentadiene, 3,4-dimethyl-1,3-hexadiene, 2,3-diethyl-1,3-butadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, 3,7-dimethyl-1,3,6-octatriene, and 2-methyl-6-methylene-1,7-octadiene. Examples of the dimethyl-1,3-butadiene include 7-methyl-3-methylene-1,6-octadiene, 1,3,7-octatriene, 2-ethyl-1,3-butadiene, 2-amyl-1,3-butadiene, 3,7-dimethyl-1,3,7-octatriene, 3,7-dimethyl-1,3,6-octatriene, 3,7,11-trimethyl-1,3,6,10-dodecatetraene, 7,11-dimethyl-3-methylene-1,6,10-dodecatriene, 2,6-dimethyl-2,4,6-octatriene, 2-phenyl-1,3-butadiene, 2-methyl-3-isopropyl-1,3-butadiene, and 1,3-cyclohexadiene. One or more of these can be used.

[0037] Examples of the acrylonitrile monomer include acrylonitrile, methacrylonitrile, α-ethoxyacrylonitrile, fumaronitrile, and the like, and one or more of these can be used.

[0038] When the surfactant composition of the present invention is used as a surfactant composition for emulsion polymerization, from the viewpoint of the effects of the present invention, it is preferably used as a surfactant composition for emulsion polymerization for emulsion polymerizing one or more monomers selected from the group consisting of acrylate monomers, styrene monomers, vinyl ester monomers, diene monomers, and acrylonitrile monomers, more preferably used as a surfactant composition for emulsion polymerization for emulsion polymerizing one or more monomers selected from the group consisting of acrylate monomers, styrene monomers, and vinyl ester monomers, and more preferably used as a surfactant composition for emulsion polymerization for emulsion polymerizing one or more monomers selected from the group consisting of acrylate monomers and styrene monomers.

[0039] When the surfactant composition of the present invention is used as a surfactant composition for emulsion polymerization, the amount of the surfactant composition used is not particularly limited and can be appropriately adjusted depending on the purpose. For example, the surfactant composition is preferably used in an amount of 0.1 to 20 parts by weight, more preferably 0.2 to 10 parts by weight, and even more preferably 0.5 to 8 parts by weight, per 100 parts by weight of the total mass of one or more polymerizable monomers selected from the group consisting of acrylate-based monomers, styrene-based monomers, vinyl ester-based monomers, diene-based monomers, and acrylonitrile-based monomers.

[0040] D. Composition for emulsion polymerization The emulsion polymerization composition of the present invention is a composition for emulsion polymerization containing the above-mentioned surfactant composition. The emulsion polymerization composition of the present invention can contain water, a polymerizable monomer, a polymerization initiator, a chain transfer agent, a pH buffer, an anionic surfactant other than the anionic surfactant represented by general formula (1), a nonionic surfactant other than the nonionic surfactant represented by general formula (2), an amphoteric surfactant, a cationic surfactant, an organic solvent, a plasticizer, a preservative, a thickener, a dispersant, etc., depending on the purpose.

[0041] When the emulsion polymerization composition of the present invention contains a surfactant composition and water, the water content is not particularly limited and can be adjusted depending on the purpose, but from the viewpoint of easily obtaining a polymer emulsion excellent in adhesive properties, mechanical stability, and water resistance, the water content is preferably 1 mass % to 95 mass %, more preferably 2 mass % to 90 mass %, and even more preferably 5 mass % to 80 mass %, relative to the total amount of the emulsion polymerization composition.

[0042] Examples of the polymerizable monomer that can be contained in the emulsion polymerization composition of the present invention include the above-mentioned acrylate monomer, styrene monomer, vinyl ester monomer, diene monomer, acrylonitrile monomer, etc. When the emulsion polymerization composition of the present invention contains a polymerizable monomer, the content of the polymerizable monomer is not particularly limited and can be adjusted according to the purpose, but from the viewpoint of easily obtaining a polymer emulsion excellent in adhesion properties, mechanical stability, and water resistance, the content of the polymerizable monomer is preferably 5% by mass to 90% by mass, more preferably 10% by mass to 80% by mass, and even more preferably 20% by mass to 70% by mass, based on the total amount of the emulsion polymerization composition.

[0043] When the emulsion polymerization composition of the present invention contains a surfactant composition and a polymerizable monomer, the content ratio of the surfactant composition to the polymerizable monomer is not particularly limited and can be adjusted depending on the purpose. From the viewpoint of easily obtaining a polymer emulsion excellent in adhesion properties, mechanical stability, and water resistance, the content of the surfactant composition is preferably 0.1 to 20 parts by mass, more preferably 0.2 to 10 parts by mass, and even more preferably 0.5 to 8 parts by mass, relative to 100 parts by mass of the polymerizable monomer in the emulsion polymerization composition.

[0044] When the emulsion polymerization composition of the present invention contains a surfactant composition, water, and a polymerizable monomer, the contents of the surfactant composition, water, and polymerizable monomer are not particularly limited and can be adjusted according to the purpose. From the viewpoint of easily obtaining a polymer emulsion excellent in adhesion properties, mechanical stability, and water resistance, it is preferable that the content of the surfactant composition is 0.1% by mass to 10% by mass, the content of the water is 10% by mass to 70% by mass, and the content of the polymerizable monomer is 20% by mass to 80% by mass, more preferably the content of the surfactant composition is 0.2% by mass to 8% by mass, the content of the water is 20% by mass to 65% by mass, and the content of the polymerizable monomer is 30% by mass to 75% by mass, and even more preferably the content of the surfactant composition is 0.5% by mass to 5% by mass, the content of the water is 25% by mass to 60% by mass, and the content of the polymerizable monomer is 35% by mass to 70% by mass.

[0045] Examples of the polymerization initiator that can be contained in the emulsion polymerization composition of the present invention include ammonium persulfate, sodium persulfate, potassium persulfate, ammonium peroxide, potassium peroxide, hydrogen peroxide, acetyl peroxide, lauroyl peroxide, benzoyl peroxide, isopropoxycarbonyl peroxide, tert-butoxycarbonyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, t-butyl hydroperoxide, cumene hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, t-butyl peroxyacetate, t-butyl peroxide ... Examples of the alkoxysilane include oxypivalate, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylvaleronitrile), 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobisdimethylisobutyrate, 2,2'-azobis[2-(hydroxymethyl)propionitrile], 2,2'-azobis(2-amidinopropane)dihydrochloride, 2,2'-azobis-2-methylpropionamidine hydrochloride, and 2,2'-azobis-2-(2-imidazolin-2-yl)propane hydrochloride. One or more of these may be contained. In addition to the polymerization initiator, an accelerator such as sodium hydrogen sulfite, metabisulfite, sodium hypophosphite, Fe(II) salt such as Mohr's salt, sodium hydroxymethanesulfinate dihydrate, hydroxylamine hydrochloride, thiourea, sodium L-ascorbate, sodium erythorbate, etc. may also be used. For example, a redox initiator such as a combination of a persulfate and sodium hydrogen sulfite or a combination of a peracid and sodium ascorbate may also be used.

[0046] When the emulsion polymerization composition of the present invention contains a polymerization initiator, the content of the polymerization initiator is not particularly limited and can be adjusted depending on the purpose. From the viewpoint of easily obtaining a polymer emulsion excellent in adhesive properties, mechanical stability, and water resistance, the content of the polymerization initiator is preferably 0.01 mass % to 5 mass %, more preferably 0.02 mass % to 3 mass %, and even more preferably 0.05 mass % to 2 mass %, relative to the total amount of the emulsion polymerization composition.

[0047] Examples of the chain transfer agent that can be contained in the emulsion polymerization composition of the present invention include butyl mercaptan, pentyl mercaptan, octyl mercaptan, dodecyl mercaptan, tetradecyl mercaptan, hexadecyl mercaptan, octadecyl mercaptan, glycidyl mercaptan, mercaptoacetic acid, mercaptoethanol, mercaptopropionic acid, 2,3-dimercapto-1-propanol, aminoethanethiol, thioglycolic acid, thiomalic acid, ethyl thioglycolate, n-butyl thioglycolate, methoxybutyl thioglycolate, 2-ethylhexyl thioglycolate, hexanedithiol, decanedithiol, 1,4-butanediol bisthiopropionate, 1,4-butanediol bisthiopropionate, 1,5-butanediol bisthiopropionate, 1,6-butanediol bisthiopropionate, 1,7-butanediol bisthiopropionate, 1,8-butanediol bisthiopropionate, 1,9 ... ,4-butanediol bisthioglycolate, ethylene glycol bisthioglycolate, ethylene glycol bisthiopropionate, trimethylolpropane tristhioglycolate, trimethylolpropane tristhiopropionate, trimethylolpropane tris(3-mercaptobutyrate), pentaerythritol tetrakisthioglycolate, pentaerythritol tetrakisthiopropionate, 2,4,6-trimercapto-s-triazine, 2-(N,N-dibutylamino)-4,6-dimercapto-s-triazine, α-terpinene, γ-terpinene, 2,4-diphenyl-4-methyl-1-pentene, etc., and these may be contained alone or in combination.

[0048] The pH buffering agent that can be contained in the emulsion polymerization composition of the present invention is not particularly limited as long as it is a compound having a pH buffering effect, and examples thereof include sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium formate, potassium formate, ammonium formate, sodium acetate, potassium acetate, ammonium acetate, monosodium phosphate, monopotassium phosphate, disodium phosphate, dipotassium phosphate, trisodium phosphate, tripotassium phosphate, acetic acid, phosphoric acid, formic acid, glycine, alanine, valine, leucine, isoleucine, serine, asparagine, glutamine, arginine, lysine, and the like, and one or more of these can be contained.

[0049] Examples of other anionic surfactants that can be contained in the emulsion polymerization composition of the present invention (excluding the anionic surfactant represented by general formula (1)) include fatty acid soaps, higher alcohol sulfates, sulfurized olefin salts, higher alkyl sulfonates, α-olefin sulfonates, sulfated fatty acid salts, sulfonated fatty acid salts, phosphate salts, sulfate salts of fatty acid esters, glyceride sulfate salts, sulfonates of fatty acid esters, α-sulfofatty acid methyl ester salts, polyoxyalkylene alkyl ether sulfate salts, polyoxyethylene alkyl phenyl ether sulfate salts, sulfate salts of alkylene oxide adducts of fatty acid alkanolamides, sulfosuccinate esters, alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl benzimidazole sulfonates, salts of N-acyl-N-methyl taurine, acyloxyethane sulfonates, alkoxy ethane sulfonic acid, N-acyl-N-carboxyethyl taurine or a salt thereof, and alkyl or alkenyl amino carboxymethyl sulfates. One or more of these may be contained.

[0050] Other nonionic surfactants (excluding the nonionic surfactant represented by general formula (2)) that can be contained in the emulsion polymerization composition of the present invention include, for example, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, glycerin fatty acid esters, polyglycerin fatty acid esters, sorbitan fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkylamines, polyoxyethylene-polyoxypropylene ethylenediamines, polyoxyethylene alkylamides, polyoxyethylene castor oil, polyoxyethylene hydrogenated castor oil, polyoxyethylene rosin esters, polyoxyethylene lanolin ethers, acetylene glycol ethylene oxide adducts, copolymers of two or more alkylene oxides such as ethylene oxide / propylene oxide block copolymers, and the like, and the composition can contain one or more of these.

[0051] Examples of the amphoteric surfactant that can be contained in the emulsion polymerization composition of the present invention include alkyl betaine type amphoteric surfactants such as alkyl dimethyl betaine and alkyl dihydroxyethyl betaine, imidazolium betaine type amphoteric surfactants such as N-fatty acyl-N-carboxymethyl-N-hydroxyethyl ethylenediamine salt and N-fatty acyl-N-carboxyethyl-N-hydroxyethyl ethylenediamine salt, amidopropyl betaine type amphoteric surfactants such as fatty acid amidopropyl betaine, amino acid type amphoteric surfactants such as alkyl amino propionate and alkyl amino dipropionate, and the like. One or more of these may be contained.

[0052] Examples of the cationic surfactant that can be contained in the emulsion polymerization composition of the present invention include alkyl(alkenyl)trimethylammonium salts, dialkyl(alkenyl)dimethylammonium salts, alkyl(alkenyl)quaternary ammonium salts, mono- or dialkyl(alkenyl)quaternary ammonium salts containing an ether group, an ester group, or an amide group, alkyl(alkenyl)pyridinium salts, alkyl(alkenyl)dimethylbenzylammonium salts, alkyl(alkenyl)isoquinolinium salts, dialkyl(alkenyl)morphonium salts, alkyl(alkenyl)amine salts, benzalkonium chloride, benzethonium chloride, and the like, and the composition can contain one or more of these.

[0053] Examples of the organic solvent that can be contained in the emulsion polymerization composition of the present invention include ketones such as methyl ethyl ketone, methyl amyl ketone, diethyl ketone, acetone, methyl isopropyl ketone, methyl isobutyl ketone, cyclohexanone, and 2-heptanone; ether solvents such as ethyl ether, dioxane, tetrahydrofuran, 1,2-dimethoxyethane, 1,2-diethoxyethane, and dipropylene glycol dimethyl ether; ester solvents such as methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, cyclohexyl acetate, ethyl lactate, and dimethyl succinate; ethylene glycol monomethyl ether; Examples of such solvents include cellosolve-based solvents such as ethylene glycol monoethyl ether; alcohol-based solvents such as methanol, ethanol, propanol, butanol, and amyl alcohol; ether ester-based solvents such as ethylene glycol monomethyl acetate, ethylene glycol monoethyl acetate, propylene glycol-1-monomethyl ether, propylene glycol-1-monomethyl ether-2-acetate, dipropylene glycol monomethyl ether acetate, 3-methoxybutyl acetate, and ethoxyethyl propionate; and BTX-based solvents such as benzene, toluene, and xylene. The solvent may contain one or more of these.

[0054] Examples of plasticizers that can be contained in the emulsion polymerization composition of the present invention include adipic acid esters, fumaric acid esters, sebacic acid esters, citrate esters, maleic acid esters, phosphate esters, epoxy fatty acid esters, aliphatic dibasic acid esters, sulfonamides, fatty acid amides, polyesters, and chlorinated paraffins, and the composition can contain one or more of these.

[0055] Examples of preservatives that can be contained in the emulsion polymerization composition of the present invention include paraben, methylparaben, benzoate, benzyl alcohol, isothiazolone, isothiazolinone, phenoxyethanol, phenylethanol, alkanediols, alkyl glyceryl ethers, triazine compounds, benzoic acid, benzoate salts, salicylic acid, salicylate salts, quaternary ammonium salt compounds, halogenated compounds, cyclic organic nitrogen compounds, sodium hydrogen sulfite, sodium hydrogen sulfate, sodium thiosulfate, ascorbate salts, thimerosal, bronopol, thiabendazole, zinc pyrithione, carbendazim, pyridine oxide thiol sodium salt, and the like. One or more of these can be contained.

[0056] Examples of thickeners that can be contained in the emulsion polymerization composition of the present invention include carrageenan, xanthan gum, guar gum, locust bean gum, ghatti gum, karaya gum, pectin, methylcellulose, ethylcellulose, hydroxypropylcellulose, hydroxyethylcellulose, hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, polyacrylic acid, polyacrylic acid-maleic acid copolymer, polyvinyl alcohol, carboxyvinyl polymer, and the like, and the composition can contain one or more of these.

[0057] Examples of dispersants that can be contained in the emulsion polymerization composition of the present invention include polyacrylic acid, polymethacrylic acid, polymaleic acid, polyitaconic acid, acrylic acid-methacrylic acid copolymer, acrylic acid-maleic acid copolymer, olefin-maleic acid copolymer, acrylic acid-sulfonic acid copolymer, maleic anhydride-styrene copolymer, maleic anhydride-ethylene copolymer, maleic anhydride-vinyl acetate copolymer, maleic anhydride-acrylic acid ester copolymer, and salts thereof, and the composition can contain one or more of these.

[0058] When the emulsion polymerization composition of the present invention contains one or more selected from the group consisting of other anionic surfactants, other nonionic surfactants, amphoteric surfactants, cationic surfactants, organic solvents, plasticizers, preservatives, thickeners, and dispersants, the content of each component is not particularly limited and can be appropriately adjusted depending on the purpose, and can be, for example, contained in an amount of 0.01 to 10 mass % each relative to the total amount of the surfactant composition.

[0059] E. Method for Producing Polymer Emulsion The method for producing the polymer emulsion of the present invention is a method for producing a polymer emulsion, which comprises polymerizing one or more polymerizable monomers selected from the group consisting of acrylate monomers, styrene monomers, vinyl ester monomers, diene monomers, and acrylonitrile monomers in the presence of the above-mentioned surfactant composition. The polymer emulsion of the present invention is excellent in adhesion properties, mechanical stability, and water resistance by polymerizing the polymerizable monomers in the presence of the above-mentioned surfactant composition. The specific method for producing the polymer emulsion of the present invention is not particularly limited, but from the viewpoint of easily obtaining a polymer emulsion excellent in adhesion properties, mechanical stability, and water resistance, it is preferable to polymerize by any of the following (Method 1) to (Method 3), for example.

[0060] (Method 1) The monomer mixture is placed in a reaction vessel and heated to 40°C to 100°C. A polymerization initiator dissolved in water or an organic solvent is added dropwise or in portions over a period of 5 minutes to 4 hours, and polymerization is carried out at 40°C to 100°C for 1 to 12 hours. (Method 2) 1% by mass to 50% by mass of the monomer mixture to be used is placed in a reaction vessel and heated to 40°C to 90°C, after which a polymerization initiator dissolved in water or an organic solvent is added dropwise or in portions and polymerized at 40°C to 90°C for 5 minutes to 4 hours, after which the remaining monomer mixture is added dropwise or in portions at 40°C to 90°C over about 1 hour to 6 hours, and further polymerized at 40°C to 90°C for 10 minutes to 3 hours. (Method 3) A polymerization initiator dissolved in water or an organic solvent is placed in a reaction vessel and the temperature is raised to 40°C to 90°C, after which a mixed solution consisting of a monomer mixture and water or an organic solvent is added dropwise or in portions at 40°C to 90°C over 2 to 6 hours, and polymerization is then continued at 40°C to 90°C for 1 to 5 hours.

[0061] In the method for producing a polymer emulsion of the present invention, the ratio of the amount of the polymerizable monomer to the amount of the surfactant composition used is not particularly limited and can be adjusted depending on the purpose. From the viewpoint of easily obtaining a polymer emulsion excellent in adhesion properties, mechanical stability, and water resistance, it is preferable to use 0.1 parts by mass to 10 parts by mass of the surfactant composition relative to 100 parts by mass of the polymerizable monomer, more preferably 0.2 parts by mass to 6 parts by mass, and even more preferably 0.5 parts by mass to 4 parts by mass.

[0062] In the method for producing the polymer emulsion of the present invention, when a polymerization initiator is used, the amount of the polymerization initiator used is not particularly limited and can be adjusted depending on the purpose. From the viewpoint of easily obtaining a polymer emulsion excellent in adhesion properties, mechanical stability, and water resistance, it is preferable to use 0.01 to 7 parts by mass of the polymerization initiator relative to 100 parts by mass of the polymerizable monomer, more preferably 0.02 to 5 parts by mass, and even more preferably 0.05 to 3 parts by mass.

[0063] In the method for producing a polymer emulsion of the present invention, when a polymerizable monomer is polymerized in an aqueous solution in the presence of a surfactant composition, the ratios of the surfactant composition, water, and polymerizable monomer used are not particularly limited and can be adjusted according to the purpose. From the viewpoint of easily obtaining a polymer emulsion excellent in adhesive properties, mechanical stability, and water resistance, the amount of the surfactant composition used is 0.1% by mass to 10% by mass, the amount of water is 10% by mass to 70% by mass, and the amount of the polymerizable monomer is 20% by mass to 80% by mass, relative to the total amount of the surfactant composition, water, and polymerizable monomer used. % by mass, more preferably the amount of surfactant composition is 0.2% by mass to 8% by mass, the amount of water is 20% by mass to 65% by mass, and the amount of polymerizable monomer is 30% by mass to 75% by mass, even more preferably the amount of surfactant composition is 0.5% by mass to 6% by mass, the amount of water is 25% by mass to 60% by mass, and the amount of polymerizable monomer is 35% by mass to 70% by mass, and even more preferably the amount of surfactant composition is 0.5% by mass to 5% by mass, the amount of water is 30% by mass to 55% by mass, and the amount of polymerizable monomer is 40% by mass to 65% by mass.

[0064] In the method for producing the polymer emulsion of the present invention, from the viewpoint of more easily obtaining a polymer emulsion excellent in adhesive properties, mechanical stability, and water resistance, among (Method 1) to (Method 3), a method of emulsion polymerization using water without using an organic solvent is preferred. Among these, from the viewpoint of more easily obtaining a polymer emulsion excellent in adhesive properties, mechanical stability, and water resistance, polymerization by the above-mentioned (Method 2) or (Method 3) is more preferred, and polymerization by (Method 3) is even more preferred.

[0065] F. Polymer emulsion The polymer emulsion of the present invention is a polymer emulsion obtained by polymerizing one or more polymerizable monomers selected from the group consisting of acrylate monomers, styrene monomers, vinyl ester monomers, diene monomers, and acrylonitrile monomers in the presence of the above-mentioned surfactant composition. The surfactant composition and polymerizable monomers used in producing the polymer emulsion of the present invention can be specifically those described above. From the viewpoint of excellent adhesion properties, mechanical stability, and water resistance, the polymer emulsion of the present invention is preferably a polymer emulsion obtained by the above-mentioned method for producing a polymer emulsion.

[0066] In the polymer emulsion of the present invention, the content of the polymer is not particularly limited and can be appropriately adjusted depending on the purpose. However, from the viewpoint of excellent adhesive properties, mechanical stability, and water resistance, in the polymer emulsion of the present invention, the content of the polymer of the anionic surfactant represented by general formula (1), the nonionic surfactant represented by general formula (2), and the polymerizable monomer is preferably 30% by mass to 90% by mass, more preferably 35% by mass to 80% by mass, even more preferably 40% by mass to 75% by mass, and even more preferably 45% by mass to 70% by mass, based on the total mass of the polymer emulsion.

[0067] In addition, in the polymer emulsion of the present invention, the water content is not particularly limited and can be appropriately adjusted depending on the purpose, but from the viewpoint of excellent adhesive properties, mechanical stability, and water resistance, the water content of the polymer emulsion of the present invention relative to the total mass of the polymer emulsion is preferably 10% by mass to 70% by mass, more preferably 20% by mass to 65% by mass, even more preferably 25% by mass to 60% by mass, and even more preferably 30% by mass to 55% by mass.

[0068] The polymer emulsion of the present invention can be used without any particular limitation in products in which polymers are usually used, and can be used as a polymer emulsion for use in, for example, paints, adhesives, pressure sensitive adhesives, inks, films, coating agents, paper coating agents, sizing agents, sealers, etc. In addition, the polymer emulsion of the present invention can contain, depending on the purpose, anionic surfactants other than the anionic surfactant represented by the above-mentioned general formula (1), nonionic surfactants other than the nonionic surfactant represented by the general formula (2), amphoteric surfactants, cationic surfactants, organic solvents, plasticizers, preservatives, thickeners, dispersants, etc., each in an amount of 0.01% by mass to 10% by mass based on the total amount of the polymer emulsion. EXAMPLES

[0069] The present invention will be described in more detail below with reference to examples. In the following examples, % is by weight unless otherwise specified. The components used in the examples and comparative examples are shown below.

[0070] <Anionic surfactants> Anionic surfactant 1: In the general formula (1), R 1 is an isoundecyl group, m is 10 (average value), and M is an ammonium group. Anionic surfactant 2: In the general formula (1), R 1 is an isoundecyl group, m is 30 (average value), and M is an ammonium group.

[0071] <Nonionic surfactant> Nonionic surfactant 1: In the general formula (2), R 2 is an isoundecyl group, and n is 10 (average value). Nonionic surfactant 2: In the general formula (2), R 2 is an isoundecyl group, and n is 30 (average value).

[0072] <Mixed Monomer> Mixed monomer 1: Mixed monomer consisting of 48% by mass of butyl acrylate, 40% by mass of 2-ethylhexyl acrylate, 10% by mass of styrene, and 2% by mass of acrylic acid Mixed monomer 2: Mixed monomer consisting of 48% by mass of butyl acrylate, 40% by mass of 2-ethylhexyl acrylate, 10% by mass of methyl methacrylate, and 2% by mass of acrylic acid

[0073] <Polymerization initiator> Polymerization initiator 1: Ammonium persulfate

[0074] [Preparation of surfactant composition] Anionic Surfactants 1 and 2 and Nonionic Surfactants 1 and 2 were mixed in the mass ratios shown in Tables 1 and 2, respectively, to prepare Surfactant Compositions 1 to 8.

[0075] [Table 1]

[0076] [Table 2]

[0077] [Preparation of polymer emulsion] 103g of distilled water was charged into a reaction vessel equipped with a reflux condenser, a stirrer, a dropping funnel and a thermometer, and the inside of the system was replaced with nitrogen gas, and then the temperature was raised to 80°C. Next, 1.2g of ammonium persulfate was charged as a polymerization initiator into the reaction vessel, and then 47g of distilled water and a mixed solution of 5g of surfactant composition and 200g of mixed monomer in the combination shown in Tables 3-4 were dropped into the reaction vessel kept at 80°C for 5 hours to carry out a polymerization reaction, and after the dropwise addition, the reaction was further carried out at 80°C for 1 hour to obtain the polymer emulsions of Examples 5-12 and Comparative Examples 5-12. The final blending ratios of each polymer emulsion are shown in Tables 3-4.

[0078] [Evaluation of adhesive properties] The obtained polymer emulsions of Examples 5 to 12 and Comparative Examples 5 to 12 were subjected to measurement of retention time according to the retention test of JIS Z 0237 (2009) and measurement of peeling force according to the peel adhesion test of JIS Z 0237 (2009), and the adhesive properties of each polymer emulsion were evaluated based on the following evaluation criteria for adhesive properties. Among these, the method of measuring the retention time was as follows: First, the polymer emulsions of Examples 5 to 12 and Comparative Examples 5 to 12 were coated on a PET film having a thickness of 38 μm, and then dried at 105 ° C for 3 minutes to prepare a coating film having a thickness of 20 μm. Next, a test piece of 25 mm × 25 mm was pressed onto a SUS plate with a 2 kg pressing roller so that the coating film side was the adhesive surface, and after aging for 24 hours, the elapsed time until the test piece fell off in a 40 ° C environment with a load of 1 kg suspended was measured as the retention time. For the measurement of peel strength, the polymer emulsions of Examples 5 to 12 and Comparative Examples 5 to 12 were applied to a PET film having a thickness of 38 μm, and then dried at 105° C. for 3 minutes to prepare a coating film having a thickness of 20 μm. Then, a test piece having a size of 25 mm×25 mm was pressed onto a SUS plate with a 2 kg pressure roller so that the coating film side was the adhesive surface, and after aging for 24 hours, the peel strength was measured as the peel strength at a speed of 300 mm / min at 180°. Then, the adhesion properties were evaluated based on the following adhesion property evaluation criteria using the retention time and peel strength measurement results of each polymer emulsion. The evaluation results are shown in Tables 3 to 4.

[0079] <Adhesive property evaluation criteria> ○: Retention time is 6 hours or more and peeling force is 5.0N or more △: Retention time is 6 hours or more and peel force is less than 5.0 N, or Holding time is less than 6 hours and peeling force is 5.0N or more ×: Holding time is less than 6 hours and peeling force is less than 5.0N

[0080] [Evaluation of mechanical stability] 50 g of the obtained polymer emulsions of Examples 5 to 12 and Comparative Examples 5 to 12 were weighed out, and a load of 20 kg was applied for 10 minutes at a rotation speed of 1000 rpm using a Marlon stability tester, and then the emulsions were filtered through a wire mesh of 80 mesh. The residues (aggregates) on the wire mesh were then washed with water and dried at 105°C for 2 hours, after which the mass was measured, and the amount of aggregates (mass%) relative to the mass of the solid content in the polymer emulsion used was calculated, and the mechanical stability was evaluated based on the calculation results and the following evaluation criteria for mechanical stability. The evaluation results are shown in Tables 3 to 4.

[0081] <Mechanical stability evaluation criteria> ○: The amount of aggregates is less than 0.50% by mass ×: The amount of aggregates is 0.50% by mass or more

[0082] [Water resistance evaluation] The obtained polymer emulsions of Examples 5 to 12 and Comparative Examples 5 to 12 were each applied to a 2 mm thick glass plate so that the thickness upon application was 100 μm, and then dried at 105° C. for 3 minutes to prepare a coating film. The film was then immersed in water at 25° C. for 6 hours and removed, and the appearance of the coating film was visually observed, and the water resistance was evaluated based on the following water resistance evaluation criteria. The evaluation results are shown in Tables 3 to 4.

[0083] <Water resistance evaluation criteria> ○: No whitening was observed ×: Whitening was observed

[0084] [Table 3]

[0085] [Table 4]

[0086] From the above results, it is evident that by polymerizing various monomers in the presence of the surfactant composition of the present invention, a polymer emulsion excellent in adhesive properties, mechanical stability, and water resistance can be obtained.

Claims

1. A surfactant composition comprising 95.5% by mass to 99.2% by mass of an anionic surfactant represented by the following general formula (1) and 0.8% by mass to 4.5% by mass of a nonionic surfactant represented by the following general formula (2): 【Chemistry 1】 (In the formula, R １ represents a linear or branched alkyl group having 8 to 15 carbon atoms, m represents a number from 5 to 50, and M represents a hydrogen atom, an alkali metal atom, or an ammonium group. 【Chemistry 2】 (In the formula, R ２ represents a linear or branched alkyl group having 8 to 15 carbon atoms, and n represents a number from 5 to 50.

2. R of the anionic surfactant represented by formula (1) １ and R of a nonionic surfactant represented by general formula (2): ２ The surfactant composition according to claim 1 , wherein and are the same alkyl group.

3. The surfactant composition according to claim 1 or 2, which is a surfactant composition for emulsion polymerization.

4. A composition for emulsion polymerization, comprising the surfactant composition according to claim 1 or 2.

5. 3. A method for producing a polymer emulsion, comprising a step of polymerizing one or more polymerizable monomers selected from the group consisting of acrylate-based monomers, styrene-based monomers, vinyl ester-based monomers, diene-based monomers, and acrylonitrile-based monomers in the presence of the surfactant composition according to claim 1 or 2.

6. A polymer emulsion obtained by polymerizing one or more polymerizable monomers selected from the group consisting of acrylate-based monomers, styrene-based monomers, vinyl ester-based monomers, diene-based monomers, and acrylonitrile-based monomers in the presence of the surfactant composition according to claim 1 or 2.