High internal phase o / w emulsion composition

Abstract

To provide a stable high internal phase O / W emulsion composition without requiring a formulation containing a high emulsifier content.SOLUTION: An O / W emulsion composition comprises, as emulsifiers, A: a water-soluble copolymer having, as essential structural units, (a) a structural unit derived from a hydrophobic monomer represented by, for example, the following formula, and (b) a structural unit derived from a hydrophilic monomer; and B: an emulsifier different from the emulsifier A, where the composition contains 50 mass% or more of an oil agent.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an O / W type emulsion composition having a high content of an oil phase component. [Background technology]

[0002] High internal phase O / W emulsion compositions contain a larger amount of the oil phase, which is the internal phase, compared to normal O / W emulsion compositions, and therefore are compatible with grease stains and makeup cosmetics, etc., and are used in cleansing cosmetics, etc. However, because they contain a large amount of the internal phase, there are problems with the emulsion stability, and various formulations have been investigated so far.

[0003] For example, Patent Document 1 discloses a high internal phase O / W type emulsion composition that contains 10 to 40% by weight of diglycerol tetraoleate to improve usability and stability. Patent Document 2 discloses a stable high internal phase O / W type emulsion composition containing polysaccharide nanocrystals (chitin nanocrystals). Patent Document 3 discloses a high internal phase O / W type emulsion composition having excellent high temperature stability, which contains 1) a diester of dimer acid and / or dimer diol, and 2) one or more synthetic polymers consisting of a polymer of a monomer selected from glucosylethyl methacrylate, methacryloyl-L-lysine, and methacryloyloxyethyl phosphorylcholine, and / or one or more synthetic polymers consisting of a copolymer having these monomers as constituent units. Patent Document 4 discloses a cleansing cosmetic composition that is suitable for removing highly water-resistant makeup cosmetics, and that is made of a high internal phase O / W type emulsion composition that contains an N-acyl glutamic acid diester. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2000-015085 A [Patent Document 2] Special Publication No. 2016-507351 [Patent Document 3] JP 2008-013450 A [Patent Document 4] JP 2000-136114 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the case of high internal phase O / W type emulsion compositions, a formulation has been proposed in which a large amount of emulsifier is blended in order to stably disperse the large amount of internal oil phase contained therein. Although such a formulation can ensure the stability of the emulsion system, the large amount of emulsifier blended may cause stickiness.

[0006] In view of the above problems, an object of the present invention is to provide a novel technique for stabilizing a high internal phase O / W type emulsion composition without relying on a formulation containing a large amount of an emulsifier. [Means for solving the problem]

[0007] Through the intensive research efforts of the present inventors, it has been found that a stable high internal phase O / W type emulsion composition in which separation of the oil phase and the water phase is suppressed can be obtained by adopting a combination of a specific water-soluble copolymer and another surfactant as an emulsifier. The present invention has been completed based on this discovery, and is as follows.

[0008] [1] The emulsifier includes the following emulsifier A and emulsifier B; Emulsifier A: a water-soluble copolymer having, as essential constituent units, one or more constituent units (a) derived from a hydrophobic monomer represented by the following general formula (II), (I) or (III) and one or more constituent units (b) derived from a hydrophilic monomer; emulsifier B: an emulsifier different from emulsifier A; An O / W type emulsion composition, characterized in that the oil content is 50% by mass or more.

[0009] General formula (II) [ka] (II) (R in general formula (II) 3 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R 4 ,R 5 may be the same or different and represent a branched acyl group not containing a ring structure and having 6 to 22 carbon atoms. X represents a group in which an OH group has been eliminated from a trihydric alcohol.

[0010] General formula (I) [ka] (I) (R in general formula (I) 1 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R 2 represents a branched hydrocarbon group having 13 to 30 carbon atoms and not containing a ring structure, or a hydrocarbon group having 6 to 12 carbon atoms and not containing a ring structure and having two or more branches.

[0011] General formula (III) [ka] (III) (R in general formula (III) 6 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R 7 ,R 8 ,R 9 may be the same or different and represent a branched acyl group not containing a ring structure and having 6 to 22 carbon atoms. Y represents a group in which an OH group has been eliminated from a tetrahydric alcohol.

[0012] By containing emulsifier A and emulsifier B, the present invention can provide an O / W emulsion composition that is highly stable and in which separation of the oil phase and the aqueous phase is suppressed.

[0013] [2] The O / W emulsion composition according to [1], wherein the content of the oil agent is more than 70 mass%. According to the present invention, a stable O / W type emulsion composition can be provided even in a formulation with a high internal phase such that the oil phase content exceeds 70 mass %.

[0014] [3] The O / W emulsion composition according to [1] or [2], wherein the total content of emulsifiers other than the emulsifier A is 1 mass% or less. In this form, the present invention can provide a high internal phase O / W type emulsion composition that has a low content of emulsifier B, is less sticky, and has an excellent feel when used, yet is highly stable.

[0015] [4] The O / W emulsion composition according to any one of [1] to [3], wherein the total content of the emulsifier is 4 mass% or less. The present invention in this form can provide a high internal phase O / W type emulsion composition that has a low total emulsifier content, is less sticky and has an excellent feel when used, and is also excellent in stability.

[0016] [5] The O / W emulsion composition according to any one of [1] to [4], wherein the content mass ratio of the emulsifier A to the emulsifier B is 1.5 to 4. By adjusting the content mass ratio of emulsifier A to emulsifier B within the above range, the stability of the emulsion system can be further improved.

[0017] [6] The O / W emulsion composition according to any one of [1] to [5], wherein the emulsifier B is a nonionic surfactant and / or an anionic surfactant. Even when a nonionic surfactant or anionic surfactant is used as emulsifier B, a high internal phase O / W type emulsion composition having excellent stability can be provided.

[0018] [7] The O / W emulsion composition according to [6], wherein the nonionic surfactant is a lipophilic nonionic surfactant. By using a lipophilic nonionic surfactant, it is possible to provide a high internal phase O / W type emulsion composition having superior stability.

[0019] [8] The O / W type emulsion composition according to [6] or [7], characterized in that the nonionic surfactant is a polyglycerol fatty acid ester and / or a polyoxyethylene alkyl ether.

[0020] [9] The O / W emulsion composition according to any one of [6] to [8], wherein the anionic surfactant is a sulfate-based anionic surfactant.

[0021] The present invention also relates to the following method for solving the problem of improving the emulsion stability of an emulsion composition emulsified with emulsifier A.

[10] A method for improving emulsion stability of an emulsion composition emulsified with the above-mentioned emulsifier A, comprising the steps of: 2. A process, characterized in that the above-mentioned emulsifier B is used as an auxiliary. Effect of the Invention

[0022] The high internal phase O / W type emulsion composition of the present invention has excellent stability. In particular, by reducing the content of emulsifier, the composition exhibits excellent stability even when applied to a formulation in which stickiness caused by the emulsifier is reduced. [Brief description of the drawings]

[0023] [Figure 1] 1 is a graph showing the results of a preliminary test, in which the adsorption rate or interfacial tension is plotted on the vertical axis and the concentration of emulsifier A is plotted on the horizontal axis for Samples 1 to 6. [Diagram 2] 1 is a graph showing the results of a preliminary test, in which the adsorption rate or interfacial tension is plotted on the vertical axis and the mass content ratio of emulsifier A to emulsifier B is plotted on the horizontal axis for Samples 1 to 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] The present invention relates to an O / W type emulsion composition containing emulsifier A and emulsifier B, and having an oil phase component content of 50% by mass or more. Hereinafter, an embodiment for carrying out the present invention will be described. Note that the scope of the present invention is not limited to the embodiment described below.

[0025] <Emulsifier A> The O / W emulsion composition of the present invention contains, as an essential component, emulsifier A, a water-soluble copolymer having, as essential structural units, one or more structural units (a) derived from a hydrophobic monomer represented by the following general formula (I), (II) or (III) and one or more structural units (b) derived from a hydrophilic monomer:

[0026] In the present invention, the term "structural unit derived from a monomer" refers to a structural unit formed by cleavage of a carbon-carbon unsaturated bond of a corresponding monomer by a polymerization reaction. Hereinafter, the hydrophobic monomer represented by the general formula (I), (II) or (III) will be described.

[0027] <Hydrophobic Monomer Represented by General Formula (I)> In the general formula (I), R 1 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R 2 represents a branched hydrocarbon group having 13 to 30 carbon atoms and not containing a ring structure, or a hydrocarbon group having 6 to 12 carbon atoms and not containing a ring structure and having two or more branches.

[0028] Here, R 1 Examples of the alkyl group represented by the formula (I) include a methyl group, an ethyl group, a propyl group, an isopropyl group, and a cyclopropyl group. 1 is preferably a hydrogen atom or a methyl group.

[0029] Also, R 2Examples of the branched hydrocarbon group having 13 to 30 carbon atoms and not containing a ring structure, as represented by the formula (I), include a 1-methyldodecanyl group, an 11-methyldodecanyl group, a 3-ethylundecanyl group, a 3-ethyl-4,5,6-trimethyloctyl group, a 1-methyltridecanyl group, a 1-hexyloctyl group, a 2-butyldecanyl group, a 2-hexyloctyl group, a 4-ethyl-1-isobutyloctyl group, a 1-methylpentadecanyl group, a 2-hexyldecanyl group, a 2-octyldecanyl group, a 2-hexyldodecanyl group, a 16-methylheptadecanyl group, a 9-methylheptadecanyl group, a 7-methyl-2-(3-methylhexyl)decanyl group, a 3,7,11,15-tetra-methylhexadecanyl group, a 2-octyldodecanyl group, a 2-decyltetradecanyl group, and a 2-dodecylhexadecanyl group.

[0030] Also, R 2Examples of the hydrocarbon group having 6 to 12 carbon atoms and having two or more branches and not containing a ring structure include a 2,2-dimethylbutyl group, a 2,3-dimethylbutyl group, a 3,3-dimethylbutyl group, a 1,3-dimethylbutyl group, a 1,2,2-trimethylpropyl group, a 1,1-dimethylpentanyl group, a 1-isopropylbutyl group, a 1-isopropyl-2-methylpropyl group, a 1,1-diethylpropyl group, a 1-ethyl-1-isopropylpropyl group, a 2-ethyl-4-methylpentyl group, a 1-propyl-2,2-dimethylpropyl group, a 1,1,2-trimethylpentyl group, a 1-isopropyl-3-methylbutyl group, a 1,2-dimethyl-1-ethylbutyl group, a 1,3-dimethyl-1-ethylbutyl group, a 1-ethyl-1-isopropylpropyl group, a 1,1-diethylpropyl group, a Examples of the alkyl group include a methylhexyl group, a 1-methyl-1-ethylpentyl group, a 1-methyl-1-propylbutyl group, a 1,4-dimethylhexyl group, a 1-ethyl-3-methylpentyl group, a 1,5-dimethylhexyl group, a 1-ethyl-6-methylheptyl group, a 1,1,3,3-tetramethylbutyl group, a 1,2-dimethyl-1-isopropylpropyl group, a 3-methyl-1-(2,2-dimethylethyl)butyl group, a 1-isopropylhexyl group, a 3.5.5-trimethylhexyl group, a 2-isopropyl-5-methylhexyl group, a 1,5-dimethyl-1-ethylhexyl group, a 3,7-dimethyloctyl group, a 2,4,5-trimethylheptyl group, a 2,4,6-trimethylheptyl group, and a 3,5-dimethyl-1-(2,2-dimethylethyl)hexyl group.

[0031] <Hydrophobic Monomer Represented by General Formula (II) or (III)> In the general formulas (II) and (III), R 3 , R 6 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R 4 ,R 5 , R 7 , R 8 , R 9 may be the same or different and represent a branched acyl group not containing a ring structure and having 6 to 22 carbon atoms. X represents a group in which an OH group has been eliminated from a trihydric alcohol.

[0032] Here, R 3 , R 6 Examples of the alkyl group represented by the formula (I) include a methyl group, an ethyl group, a propyl group, an isopropyl group, and a cyclopropyl group. 3 is preferably a hydrogen atom or a methyl group.

[0033] Also, R 4 , R 5 , R 7 , R 8 , R 9Examples of the branched acyl group having 6 to 22 carbon atoms and not containing a ring structure represented by the formula (I) include a 2-methylpentanoyl group, a 3-methylpentanoyl group, a 4-methylpentanoyl group, a 2-ethylbutanoyl group, a 2-ethylbutanoyl group, a 2,2-dimethylbutanoyl group, a 3,3-dimethylbutanoyl group, a 2-methylhexanoyl group, a 4-methylhexanoyl group, a 5-methylhexanoyl group, a 2,2-dimethylpentanoyl group, a 4,4-dimethylpentanoyl group, a 2-methylheptanoyl group, a 2-ethylhexyl group, a 2-propylpentano ... Noyl group, 2,2-dimethylhexanoyl group, 2,2,3-trimethylpentanoyl group, 2-methyloctanoyl group, 3,3,5-trimethylhexanoyl group, 2-methylnonanoyl group, 4-methylnonanoyl group, 8-methylnonanoyl group, 4-ethyloctanoyl group, 2-ethyloctanoyl group, 2-butylhexanoyl group, 2-tert-butylhexanoyl group, 2,2-diethylhexanoyl group, 2,2-dimethyloctanoyl group, 3,7-dimethyloctanoyl group, neodecanoyl group, 7-methyldecanoyl group, 2 -methyl-2-ethyloctanoyl group, 2-methylundecanoyl group, 10-methylundecanoyl group, 2,2dimethyldecanoyl group, 2-ethyldecanoyl group, 2-butyloctanoyl group, diethyloctanoyl group, 2-tert-butyl-2,2,4-trimethylpentanoyl group, 10-methyldodecanoyl group, 3-methyldodecanoyl group, 4-methyldodecanoyl group, 11-methyldodecanoyl group, 10-ethylundecanoyl group, 12-methyltridecanoyl group, 2-butyldecanoyl group, 2-hexyloctanoyl group Examples of such alkyl groups include 1,2-dimethyl-2,4-dimethylpentanoyl, 1,2-dimethyl-2,4-dimethylhexanoyl, 1,2 ...

[0034] In a preferred embodiment of the present invention, in the general formulas (II) and (III), R 4 , R 5 , R 7 , R 8 , R 9 may be the same or different and are a branched acyl group having 10 to 22 carbon atoms and not containing a ring structure, or an acyl group having 6 to 9 carbon atoms and having two or more branches and not containing a ring structure.

[0035] In such a preferred embodiment, R 4 ,R 5 , R 7 , R 8 , R 9 Examples of the branched acyl group having 10 to 22 carbon atoms and not containing a ring structure, which is represented by the formula (I), include a 2-methylnonanoyl group, a 4-methylnonanoyl group, an 8-methylnonanoyl group, a 4-ethyloctanoyl group, a 2-ethyloctanoyl group, a 2-butylhexanoyl group, a 2-tert-butylhexanoyl group, a 2,2-diethylhexanoyl group, a 2,2-dimethyloctanoyl group, a 3,7-dimethyloctanoyl group, a neodecanoyl group, a 7-methyldecanoyl group, a 2-methyl-2-ethyloctanoyl group, a 2-methylundecanoyl group, a 10-methylundecanoyl group, a 2,2dimethyldecanoyl group, a 2-ethyldecanoyl group, a 2-butyloctanoyl group, a diethyloctanoyl group, a 2-tert-butyl-2,2,4-trimethylpentanoyl group, a 10-methyl Examples of the alkyl group include ethyldodecanoyl group, 3-methyldodecanoyl group, 4-methyldodecanoyl group, 11-methyldodecanoyl group, 10-ethylundecanoyl group, 12-methyltridecanoyl group, 2-butyldecanoyl group, 2-hexyloctanoyl group, 2-butyl-2-ethyloctanoyl group, 12-methyltetradecanoyl group, 14-methylpentadecanoyl group, 2-butyldodecanoyl group, 2-hexyldecanoyl group, 16-methylheptadecanoyl group, 2,2-dimethylhexanoyl group, 2-butylhexadecanoyl group, 2-hexyldodecanoyl group, 2,4,10,14-tetramethylpentanoyl group, 18-methylnonadecanoyl group, 3,7,11,15-tetramethylhexadecanoyl group, and 19-methyleicosanoyl group.

[0036] In addition, in the preferred embodiment, R 4 , R 5 , R 7 , R 8 , R 9 Examples of the acyl group having 6 to 9 carbon atoms, not containing a ring structure, having two or more branches, represented by the formula (1), include a 2,2-dimethylbutanoyl group, a 3,3-dimethylbutanoyl group, a 2,2-dimethylpentanoyl group, a 4,4-dimethylpentanoyl group, a 2,2-dimethylhexanoyl group, a 2,2,3-trimethylpentanoyl group, and a 3,5,5-trimethylhexanoyl group.

[0037] The group derived from a trihydric alcohol, represented by X in general formula (II), is not particularly limited as long as it is a group obtained by removing an OH group from a trihydric alcohol. Suitable examples include groups obtained by removing an OH group from a trihydric alcohol selected from the group consisting of glycerin, trimethylolpropane, and trimethylolethane.

[0038] The group derived from a tetrahydric alcohol, represented by Y in general formula (III), is not particularly limited as long as it is a group in which an OH group has been separated from a tetrahydric alcohol. Suitable examples of the group include a group in which an OH group has been separated from a tetrahydric alcohol selected from the group consisting of diglycerol, pentaerythritol, erythritol, D-threitol, and L-threitol.

[0039] In a more preferred embodiment of the present invention, the hydrophobic monomer represented by general formula (II) is a hydrophobic monomer represented by the following general formula (V):

[0040] General formula (V) [ka] (V) (R in general formula (V) 13 , R 14may be the same or different, and each represents a branched acyl group not containing a ring structure and having 16 to 22 carbon atoms. Z represents a group in which an OH group has been eliminated from a trihydric alcohol.

[0041] R in general formula (V) 13 , R 14 The acyl group has 12 to 22 carbon atoms, more preferably 14 to 20 carbon atoms, and further preferably 16 to 20 carbon atoms. In addition, R in general formula (V) 13 , R 14 The acyl group preferably has 9-21 carbon atoms in its main chain, more preferably 12-20 carbon atoms, and further preferably 16-18 carbon atoms. In addition, R in the general formula (V) 13 , R 14 The number of branches in the acyl group is preferably 1 to 3, more preferably 1 or 2, and further preferably 1. Furthermore, R in general formula (V) 13 , R 14 In the acyl group, the larger the carbon position number in the main chain to which the branched chain is bonded, the more preferable it is. Specifically, the branched chain is bonded to preferably the 1st to 3rd carbons, more preferably the 1st or 2nd carbons, and even more preferably the 1st carbon, from the carbon at the end of the main chain.

[0042] R 13 , R 14 Specific preferred examples of the alkyl group include a 10-methylundecanoyl group, a 10-methyldodecanoyl group, a 11-methyldodecanoyl group, a 10-ethylundecanoyl group, a 12-methyltridecanoyl group, a 12-methyltetradecanoyl group, a 14-methylpentadecanoyl group, a 16-methylheptadecanoyl group, a 2,4,10,14-tetramethylpentanoyl group, a 18-methylnonadecanoyl group, a 3,7,11,15-tetramethylhexadecanoyl group, and a 19-methyleicosanoyl group.

[0043] The group derived from a trihydric alcohol, represented by Z in general formula (V), is not particularly limited as long as it is a group obtained by removing an OH group from a trihydric alcohol. Suitable examples of the group include groups obtained by removing an OH group from a trihydric alcohol selected from the group consisting of glycerin, trimethylolpropane, and trimethylolethane.

[0044] <Constituent unit b> As the hydrophilic monomer, polymerizable carboxylic acids and compounds represented by the following general formula (IV), (VI), (VII) and (VIII) can be used.

[0045] <Polymerizable Carboxylic Acid> In the present invention, specific examples of the polymerizable carboxylic acid or its salt include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, and their sodium salts, potassium salts, ammonium salts, and amine salts. Among these, acrylic acid, methacrylic acid, and their salts are particularly preferred because of their high polymerizability. When introducing a structural unit derived from a polymerizable carboxylic acid salt into the water-soluble copolymer of the present invention, the polymerizable carboxylic acid may be converted into a salt in advance and then subjected to a polymerization reaction, or the structural unit derived from the polymerizable carboxylic acid may be introduced into the water-soluble copolymer by polymerization reaction, and then neutralized with a base to convert into a salt.

[0046] <Hydrophilic Monomer Represented by General Formula (IV)> As the hydrophilic monomer in the present invention, a hydrophilic monomer represented by the following general formula (IV) may be used.

[0047] General formula (IV) [ka] (IV) (R in general formula (IV) 10 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R 11 represents an alkylene group having 2 to 4 carbon atoms which may have a hydroxyl group; R 12represents a hydrogen atom, an aromatic hydrocarbon group having 6 to 10 carbon atoms, an aliphatic hydrocarbon group having 1 to 14 carbon atoms, or an acyl group having 1 to 12 carbon atoms. n represents an integer of 6 to 40.

[0048] In the general formula (IV), R 10 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R 11 represents an alkylene group having 2 to 4 carbon atoms which may have a hydroxyl group; R 12 represents a hydrogen atom, an aromatic hydrocarbon group having 6 to 10 carbon atoms, an aliphatic hydrocarbon group having 1 to 14 carbon atoms, or an acyl group having 1 to 12 carbon atoms. n represents an integer of 6 to 40.

[0049] In the general formula (IV), R 10 Examples of the alkyl group represented by the formula (I) include a methyl group, an ethyl group, a propyl group, an isopropyl group, and a cyclopropyl group. 10 is preferably a hydrogen atom or a methyl group.

[0050] Also, R 11 Examples of the alkylene group represented by the formula (I) include an ethylene group, a propylene group, an isopropylene group, a 2-hydroxypropylene group, a 1-hydroxy-2-methylethylene group, and a 2-hydroxy-1-methylethylene group. Of these, an ethylene group or a propylene group is preferred, and an ethylene group is more preferred.

[0051] Also, R 12 Among the groups represented by the formula (I), examples of aromatic groups having 6 to 10 carbon atoms include phenyl, benzyl, methylphenyl, and ethylphenyl groups; examples of aliphatic hydrocarbon groups having 1 to 14 carbon atoms include methyl, ethyl, butyl, tertiary butyl, hexyl, cyclohexyl, octyl, 2-ethylhexyl, and lauryl groups; and examples of acyl groups having 1 to 12 carbon atoms include formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, and lauroyl groups. Of these, R 12The group represented by the formula: is preferably an aliphatic hydrocarbon group having 1 to 14 carbon atoms, and more preferably an alkyl group having 1 to 12 carbon atoms.

[0052] Furthermore, n in the general formula (IV) is a numerical value ranging from 6 to 40.

[0053] Among the monomers represented by the general formula (IV), R 11 Specific examples of monomers in which n is a propylene group include polypropylene glycol (9) monoacrylate, polypropylene glycol (13) monoacrylate, polypropylene glycol (9) monomethacrylate, and polypropylene glycol (13) monomethacrylate. The number in parentheses indicates n. Many of these polymers are available as commercial products. Specific examples of these commercial products include products under the trade name "BLEMMER" AP-400, AP-550, AP-800, PP-500, and PP-800 (all manufactured by NOF Corporation).

[0054] Among the monomers represented by the general formula (IV), R 11 Specific examples of the monomer in which is an ethylene group include polyethylene glycol (10) monoacrylate, polyethylene glycol (8) monomethacrylate, polyethylene glycol (23) monoacrylate, polyethylene glycol (23) monomethacrylate, methoxypolyethylene glycol (9) acrylate, methoxypolyethylene glycol (9) methacrylate, methoxypolyethylene glycol (23) methacrylate, oleyloxypolyethylene glycol (18) methacrylate, lauroxypolyethylene glycol (18) acrylate, lauroyloxypolyethylene glycol (10) methacrylate, and stearoxypolyethylene glycol (30) monomethacrylate.

[0055] The above-mentioned hydrophilic monomers can be obtained in high yields by esterification reaction of the corresponding polyethylene glycol, polyethylene glycol monoether, or polyethylene glycol monoester with the chloride or anhydride of acrylic acid or methacrylic acid. In addition, since many commercial products are already available, it is also possible to use such commercial products. Specific examples of such commercial products include trade names Blenmar, AE-400, PE-350, AME-400, PME-400, PME-1000, ALE-800, PSE-1300, etc. (all manufactured by Nippon Oil & Fats Co., Ltd.).

[0056] <Hydrophilic Monomer Represented by General Formula (VI)> As the hydrophilic monomer in the present invention, a hydrophilic monomer represented by the following general formula (VI) may be used.

[0057] (General formula VI) [ka] (VI) (R in general formula (VI) 15 represents a hydrogen atom or a methyl group.)

[0058] Specific examples of the hydrophilic monomer represented by the general formula (VI) include 2-acryloyloxyethyl phosphorylcholine (APC) and 2-methacryloyloxyethyl phosphorylcholine (MPC). These monomers can be synthesized, for example, by the following method described in Polymer Journal, Vol. 22, No. 5.

[0059] <Synthesis method> 2-Bromoethyl phosphoryl dichloride is reacted with 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate to obtain 2-methacryloyloxyethyl-2'-bromoethyl phosphate or 2-acryloyloxyethyl-2-bromoethyl phosphate, and then these compounds are reacted with triethylamine in methanol.

[0060] <Hydrophilic Monomer Represented by General Formula (VII)> As the hydrophilic monomer in the present invention, a hydrophilic monomer represented by the following general formula (VII) may be used.

[0061] General formula (VII) [ka] (VII) (R in general formula (VII) 16 represents a hydrogen atom or a methyl group, and GO- represents a group obtained by removing a hydrogen atom from the hydroxyl group at the 1-position of a reducing sugar. m represents 2 or 3, and l represents an integer from 1 to 5.

[0062] In the hydrophilic monomer represented by the general formula (VII), the reducing sugar of the group obtained by removing hydrogen from the hydroxyl group at the 1-position of the reducing sugar represented by GO- is specifically exemplified by one or more selected from the group consisting of monosaccharides such as glucose, mannose, galactose, arabinose, xylose, ribose, etc., disaccharides such as maltose, lactose, cellobiose, etc., trisaccharides such as maltotriose, and oligosaccharides such as maltooligosaccharides, among which, one or more selected from the group consisting of glucose, galactose, arabinose, xylose, ribose, maltose, lactose, cellobiose is preferred, and glucose is particularly preferred. In addition, glucosyloxyethyl methacrylate (hereinafter abbreviated as GEMA) or glucosyloxyethyl acrylate (hereinafter abbreviated as GEA) is preferred as the monomer represented by the general formula (VII).

[0063] <Hydrophilic Monomer Represented by General Formula (VIII)> As the hydrophilic monomer in the present invention, a hydrophilic monomer represented by the following general formula (VIII) may be used.

[0064] General formula (VIII) [ka] (VIII) (R in general formula (VIII) 17 represents a hydrogen atom or a methyl group, R 18 represents an amino acid residue, a polyamine residue, or an amino alcohol residue. Q represents an oxygen atom or a group represented by NH.

[0065] In the monomer of general formula (VIII), R 18 The amino acid of the amino acid residue represented by is not particularly limited as long as it is a commonly known amino acid, and specific examples include glycine, alanine, glutamine, lysine, arginine, etc. Among these, lysine residue is particularly preferred because the resulting water-soluble copolymer has an excellent effect of restoring the skin barrier.

[0066] Also, R 18 The polyamine in the polyamine residue represented by means an amine having two or more amino groups in the same molecule, which may be substituted with an alkyl group, specifically includes diamines, triamines, tetraamines, or amines in which the hydrogen atoms of these amino groups are substituted with an alkyl group. Among these, diamines are preferred because the skin topical preparation containing the obtained water-soluble copolymer has a particularly excellent feeling when used, and particularly preferred examples include ethylenediamine, 1,4-diamino-n-butane, 1,6-diamino-n-hexane, etc., because the raw materials are easily available when synthesizing.

[0067] In addition, R 18 The amino alcohol in the amino alcohol residue represented by the formula (I) means a compound having an amino group which may be substituted with an alkyl group and an alcoholic hydroxyl group in the same molecule. The amino alcohol is not particularly limited as long as it is a commonly known one, and specific examples include ethanolamine, triethylaminoethanol, etc.

[0068] The salt of the monomer represented by general formula (VIII) is not particularly limited, and specific examples thereof include sodium salts, potassium salts, ammonium salts, amine salts, etc., in which the acid moiety is neutralized with a base, and hydrochlorides, sulfates, nitrates, phosphates, citrates, oxalates, carbonates, etc., in which the amino group moiety is neutralized with an acid. When introducing a structural unit derived from a salt of the monomer represented by general formula (VIII) into the water-soluble copolymer of the present invention, the monomer represented by general formula (VIII) may be previously converted into a salt and then subjected to a polymerization reaction, or the structural unit derived from the monomer represented by general formula (VIII) may be introduced into the water-soluble copolymer by a polymerization reaction, and then neutralized into a salt.

[0069] Suitable specific examples of the monomer represented by formula (VIII) and its salts include compounds having the following structures and their salts.

[0070] [ka]

[0071] [ka]

[0072] [ka]

[0073] [ka]

[0074] [ka]

[0075] [ka]

[0076] [ka]

[0077] [ka]

[0078] [ka]

[0079] [ka]

[0080] [ka]

[0081] The hydrophilic monomer represented by the general formula (VIII) can be synthesized, for example, by an esterification reaction or an amidation reaction using (meth)acrylic acid or (meth)acrylic acid chloride as shown below.

[0082] [ka] [ka] (R in the reaction formula 17 represents a hydrogen atom or a methyl group, R 18 represents an amino acid residue, a polyamine residue, or an amino alcohol residue. Q represents an oxygen atom or a group represented by NH.

[0083] As described above, in the present invention, the hydrophilic polymer may be a polymerizable carboxylic acid, or a compound represented by the following general formula (IV), the following general formula (VI), the following general formula (VII), or the following general formula (VIII). In a preferred embodiment of the invention, the water-soluble copolymer comprises units derived from general formula (IV) above.

[0084] <Water-soluble copolymer> In the present invention, a water-soluble copolymer having a constitutional unit derived from general formula (II) and a constitutional unit derived from general formula (IV) can be preferably used, and more preferably a water-soluble copolymer having a constitutional unit derived from general formula (V) and a constitutional unit derived from general formula (IV) can be used. Of these water-soluble copolymers, it is particularly preferable to use (methoxy PEG-23 methacrylate / glyceryl diisostearate methacrylate) copolymer. By containing such a water-soluble copolymer, an emulsion composition that is less irritating, less sticky, and has better emulsion stability can be obtained.

[0085] The (methoxy PEG-23 methacrylate / glyceryl diisostearate methacrylate) copolymer contains, as the structural unit (a), a hydrophobic monomer represented by the general formula (V), R 13 , R 14 The copolymer mainly contains a structural unit (a) derived from a hydrophobic monomer in which the R 1 group is a 16-methylheptadecanoyl group. As the structural unit (b), among the hydrophilic monomers represented by the general formula (IV), R 10 is a methyl group, R 11 is an ethylene group, R 12 The copolymer mainly contains structural units (b) derived from a hydrophilic monomer in which n is a methyl group and n is 23.

[0086] In the present invention, the proportion of the structural unit (a) in all structural units in the water-soluble copolymer is preferably from 1 to 50 mass %, more preferably from 20 to 50 mass %, and even more preferably from 30 to 40 mass %. By setting the proportion of the structural unit (a) in the water-soluble copolymer within the above range, it is possible to provide an O / W type emulsion composition with reduced sticky feeling.

[0087] In the present invention, the proportion of the structural unit (b) in all structural units in the water-soluble copolymer is preferably from 50 to 99 mass %, more preferably from 50 to 80 mass %, and even more preferably from 60 to 70 mass %. By setting the proportion of the structural unit (b) in the water-soluble copolymer within the above range, it is possible to provide an O / W type emulsion composition with reduced sticky feeling.

[0088] In the present invention, the mass ratio of the structural unit (a) to the structural unit (b) constituting the water-soluble copolymer is preferably 10:90 to 50:50, more preferably 20:80 to 50:50, and even more preferably 30:70 to 40:60.

[0089] The molar ratio of the structural unit (a) to the structural unit (b) constituting the water-soluble copolymer is preferably 15:85 to 62:38, more preferably 29:71 to 62:38, and even more preferably 41:59 to 52:48. By setting the mass ratio and molar ratio of the structural unit (a) and the structural unit (b) in the water-soluble copolymer within the above range, it is possible to obtain a water-soluble copolymer having excellent emulsifying power and suitable for forming an O / W type emulsion composition.

[0090] In the present invention, the average molecular weight of the water-soluble copolymer is preferably 20,000 to 110,000, more preferably 20,000 to 80,000, more preferably 30,000 to 80,000, more preferably 40,000 to 70,000, further preferably 50,000 to 70,000, and further preferably 57,000 to 66,000. The average molecular weight herein refers to the weight average molecular weight in terms of polystyrene measured by GPC.

[0091] <Emulsifier B> The O / W emulsion composition of the present invention contains, as an essential component, an emulsifier B. The emulsifier B is an emulsifier different from the emulsifier A. A more preferred form of the emulsifier B will be described below.

[0092] The emulsifier B may be a nonionic surfactant or an ionic surfactant. The ionic surfactant may be any of an anionic surfactant, a cationic surfactant, and an amphoteric surfactant. Among the ionic surfactants, the anionic surfactant is particularly preferred as the emulsifier B.

[0093] The nonionic surfactant used as emulsifier B is not limited, and examples thereof include polyglycerol fatty acid esters (e.g., polyglycerol-2 monooleate, polyglycerol-2 dioleate, polyglycerol-10 pentaoleate, polyglycerol-10 pentaisostearate, polyglycerol-10 decaisostearate, etc.); polyoxyethylene alkyl ethers (e.g., polyoxyethylene (5) behenyl ether, polyoxyethylene (2) oleyl ether, etc.); polyglycerol-modified silicones (e.g., polyglyceryl-3 disiloxane dimethicone, polyglyceryl-3 polydimethylsiloxyethyl dimethicone, etc.); sorbitan fatty acid esters (e.g., sorbitan monooleate, sorbitan monostearate, sorbitan monoisostearate, sorbitan monolaurate, sorbitan monopalmitoyl esters, etc.); sorbitan monostearate, sorbitan sesquioleate, sorbitan trioleate, diglycerol sorbitan penta-2-ethylhexylate, diglycerol sorbitan tetra-2-ethylhexylate, etc.); glycerin fatty acids (e.g., glyceryl monocottonseed oil fatty acid, glyceryl monoerucate, glyceryl sesquioleate, glyceryl monostearate, glyceryl α,α'-oleate pyroglutamate, glyceryl (monostearate / malate), etc.); propylene glycol fatty acid esters (e.g., propylene glycol monostearate, etc.); polyoxyethylene castor oil / hydrogenated (hydrogenated) castor oil derivatives (polyoxyethylene (10) castor oil, polyoxyethylene (10) hydrogenated (hydrogenated) castor oil, etc.); and glycerin alkyl ethers.

[0094] Also, polyglycerol fatty acid esters (e.g., polyglyceryl monooleate, polyglyceryl monostearate, etc.); polyoxyethylene sorbitan fatty acid esters (e.g., polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tetraoleate, etc.); polyoxyethylene sorbitan fatty acid esters (e.g., polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan pentaoleate, polyoxyethylene sorbitan monostearate, etc.); polyoxyethylene glycerin fatty acid esters (e.g., polyoxyethylene monooleates such as polyoxyethylene glycerin monostearate, polyoxyethylene glycerin monoisostearate, and polyoxyethylene glycerin triisostearate); polyoxyethylene fatty acid esters (e.g., polyoxyethylene distearate, polyoxyethylene monodioleate, distearin ethylene glycol acid, etc.); polyoxyethylene alkyl ethers (e.g., polyoxyethylene (23) lauryl ether, polyoxyethylene (20) oleyl ether, polyoxyethylene (20) stearyl ether, polyoxyethylene (20) behenyl ether, polyoxyethylene (25)-2-octyldodecyl ether, polyoxyethylene cholestanol ether, etc.); polyoxyethylene alkyl phenyl ethers (e.g., polyoxyethylene (10) nonylphenyl ether, etc.); Pluronic surfactants (e.g., Pluronic (registered trademark), etc.); polyoxyethylene-polyoxypropylene alkyl ethers (e.g., polyoxyethylene-polyoxypropylene cetyl ether, polyoxyethylene-polyoxypropylene-2-decyltetradecyl ether, polyoxyethylene-polyoxypropylene monobutyl ether, polyoxyethylene-polyoxypropylene hydrogenated lanolin, polyoxyethylene-polyoxypropylene glycerin ether, etc.); tetra-polyoxyethylene-tetra-polyoxypropylene ethylenediamine condensates (e.g., Tetronic, etc.);Hydrophilic nonionic surfactants selected from polyoxyethylene castor oil hydrogenated (hydrogenated) castor oil derivatives (e.g., polyoxyethylene castor oil, polyoxyethylene hydrogenated (hydrogenated) castor oil, polyoxyethylene hydrogenated (hydrogenated) castor oil monoisostearate, polyoxyethylene hydrogenated (hydrogenated) castor oil triisostearate, polyoxyethylene hydrogenated (hydrogenated) castor oil monopyroglutamic acid monoisostearate diester, polyoxyethylene hydrogenated (hydrogenated) castor oil maleic acid, etc.); polyoxyethylene beeswax / lanolin derivatives (e.g., polyoxyethylene sorbitol beeswax, etc.); alkanolamides (e.g., coconut oil fatty acid diethanolamide, lauric acid monoethanolamide, fatty acid isopropanolamide, etc.); polyoxyethylene propylene glycol fatty acid esters; polyoxyethylene alkylamines; polyoxyethylene fatty acid amides; sucrose fatty acid esters; alkyl glucosides; alkyl ethoxydimethylamine oxides; and trioleyl phosphate.

[0095] In a preferred embodiment of the present invention, a lipophilic nonionic surfactant is used when a nonionic surfactant is used as emulsifier B. More specifically, a nonionic surfactant having an HLB of preferably 10 or less, more preferably 9 or less, and even more preferably 8 or less is used.

[0096] In the present invention, when a nonionic surfactant is used as emulsifier B, it is preferable to use a polyglycerol fatty acid ester and / or a polyoxyethylene alkyl ether. It is particularly preferable to use lipophilic polyglycerol fatty acid esters and / or polyoxyethylene alkyl ethers. More specifically, it is preferable to use a polyglycerol fatty acid ester and / or a polyoxyethylene alkyl ether having an HLB of preferably 10 or less, more preferably 9 or less, and even more preferably 8 or less.

[0097] The anionic surfactant that can be used as emulsifier B is not particularly limited, and examples thereof include fatty acid soaps (e.g., sodium laurate, sodium palmitate, etc.); higher alkyl sulfates (e.g., sodium lauryl sulfate, potassium lauryl sulfate, etc.); alkyl ether sulfates (e.g., POE triethanolamine lauryl sulfate, POE sodium lauryl sulfate, etc.); N-acylsarcosinates (e.g., sodium lauroyl sarcosinate, etc.); higher fatty acid amide sulfonates (e.g., sodium N-myristoyl-N-methyl taurine, sodium coconut oil fatty acid methyl tauride, sodium lauryl methyl tauride, etc.); phosphates (sodium POE oleyl ether phosphate, sodium POE stearyl ether phosphate, etc.); sulfosuccinates (e.g., sodium di-2-ethylhexyl sulfosuccinate, sodium monolauroyl monoethanolamide polyoxyethylene sulfosuccinate, sodium lauryl polypropylene glycol, etc.), and the like. sodium lycol sulfosuccinate, etc.); alkylbenzene sulfonates (e.g., sodium linear dodecylbenzene sulfonate, triethanolamine linear dodecylbenzene sulfonate, linear dodecylbenzene sulfonic acid, etc.); higher fatty acid ester sulfate salts (e.g., sodium hydrogenated coconut oil fatty acid glycerin sulfate, etc.); N-acyl glutamates (e.g., monosodium N-lauroyl glutamate, disodium N-stearoyl glutamate, monosodium N-myristoyl-L-glutamate, etc.); sulfated oils (e.g., turmeric oil, etc.); POE alkyl ether carboxylic acids; POE alkyl allyl ether carboxylates; α-olefin sulfonates; higher fatty acid ester sulfonates; secondary alcohol sulfate salts; higher fatty acid alkylolamide sulfate salts; sodium lauroyl monoethanolamide succinate; ditriethanolamine N-palmitoyl aspartate; sodium caseinate, etc.

[0098] There are no particular limitations on the cationic surfactant that can be used as emulsifier B, and examples thereof include alkyltrimethylammonium salts (e.g., stearyltrimethylammonium chloride, lauryltrimethylammonium chloride, etc.); alkylpyridinium salts (e.g., cetylpyridinium chloride, etc.); distearyldimethylammonium chloride dialkyldimethylammonium salts; poly(N,N'-dimethyl-3,5-methylenepiperidinium chloride); alkyl quaternary ammonium salts; alkyldimethylbenzylammonium salts; alkylisoquinolinium salts; dialkylmorphonium salts; POE alkylamines; alkylamine salts; polyamine fatty acid derivatives; amyl alcohol fatty acid derivatives; benzalkonium chloride; benzethonium chloride, etc.

[0099] There are no particular limitations on the amphoteric surfactant that can be used as emulsifier B, and examples thereof include imidazoline-based amphoteric surfactants (e.g., 2-undecyl-N,N,N-(hydroxyethylcarboxymethyl)-2-imidazoline sodium, 2-cocoyl-2-imidazolinium hydroxide-1-carboxyethyloxy disodium salt, etc.); betaine-based surfactants (e.g., 2-heptadecyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, lauryl dimethylaminoacetic acid betaine, alkyl betaine, amido betaine, sulfobetaine, etc.).

[0100] In a preferred embodiment of the present invention, emulsifier B is an anionic surfactant among ionic surfactants. Among the anionic surfactants, particularly preferred are sulfate anionic surfactants.Sulfate anionic surfactants include alkyl sulfates such as lauryl sulfate, sulfosuccinates such as sodium lauryl sulfosuccinate, and fatty acid glyceryl sulfates such as sodium cocoglyceryl sulfate, and fatty acid glyceryl sulfates are particularly preferred. As the fatty acid residue (acyl group) constituting the fatty acid glycerol sulfate salt, those having 10 to 30 carbon atoms are preferred. For example, lauroyl group, myristoyl group, palmitoyl group, stearoyl group, isostearoyl group, behenoyl group, oleoyl group, etc. can be preferably exemplified, and it is also possible to use coconut oil fatty acid residue, beef tallow fatty acid residue, palm oil fatty acid residue, etc., which are natural mixtures of these. Among them, coconut oil fatty acid glyceryl sulfate salt is most preferred. As these salts, as long as they are used in external skin preparations, they can be used without particular limitation. For example, alkali metal salts such as sodium salt and potassium salt, alkaline earth metal salts such as calcium salt and magnesium salt, ammonium salt, organic amine salts such as triethylamine salt, triethanolamine salt, and monoethanolamine salt, basic amino acid salts such as lysine salt and alginate salt, etc. can be preferably exemplified. Particularly preferred salts are alkali metal salts, and among them, sodium salt is the most preferred.

[0101] <O / W type emulsion composition> The present invention is an O / W type emulsion composition in which the content of the oil agent is 50% by mass or more. The content of the oil agent is preferably 55% by mass or more, more preferably 60% by mass or more, still more preferably 65% by mass or more, still more preferably 70% by mass or more, still more preferably 75% by mass or more, still more preferably 80% by mass or more, still more preferably 85% by mass or more. By including emulsifier A and emulsifier B, it is possible to provide a stable O / W type emulsion composition even in a form containing a large amount of the oil agent as in the above numerical range.

[0102] The upper limit of the content of the oil agent is not particularly limited, but it can be set, for example, to 99% by mass or less, 95% by mass or less, or 90% by mass or less according to the purpose.

[0103] The oil agent used in the present invention is not particularly limited, and can contain liquid oils and fats, solid oils and fats, waxes, hydrocarbon oils, higher fatty acids, higher alcohols, ester oils, silicone oils, etc.

[0104] Examples of liquid oils and fats include avocado oil, camellia oil, turtle oil, macadamia nut oil, corn oil, mink oil, olive oil, rapeseed oil, egg yolk oil, sesame oil, persic oil, wheat germ oil, sasanqua oil, castor oil, linseed oil, safflower oil, cottonseed oil, perilla oil, meadowfoam oil, soybean oil, peanut oil, tea seed oil, kaya oil, rice bran oil, Chinese giri oil, Japanese tung oil, jojoba oil, germ oil, triglycerin, glycerin trioctanoate, and glycerin triisopalmitate.

[0105] Examples of solid fats and oils include cacao butter, coconut oil, horse tallow, hardened coconut oil, palm oil, beef tallow, mutton tallow, hardened beef tallow, palm kernel oil, lard, beef bone fat, Japan Rice Kernel Oil, hardened oil, beef foot fat, Japan Rice, and hardened castor oil.

[0106] Examples of waxes include beeswax, candelilla wax, cotton wax, carnauba wax, bayberry wax, ivory wax, whale wax, montan wax, bran wax, lanolin, kapok wax, lanolin acetate, liquid lanolin, sugarcane wax, lanolin fatty acid isopropyl, hexyl laurate, reduced lanolin, jojoba wax, hard lanolin, shellac wax, POE lanolin alcohol ether, POE lanolin alcohol acetate, POE cholesterol ether, lanolin fatty acid polyethylene glycol, and POE hydrogenated lanolin alcohol ether.

[0107] Examples of the hydrocarbon oil include liquid paraffin, ozokerite, pristane, paraffin, ceresin, squalene, petrolatum, and microcrystalline wax.

[0108] Examples of higher fatty acids include lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, 12-hydroxystearic acid, undecylenic acid, and tall acid.

[0109] Examples of higher alcohols include cetyl alcohol, stearyl alcohol, behenyl alcohol, batyl alcohol, myristyl alcohol, and cetostearyl alcohol.

[0110] Ester oils include isopropyl myristate, cetyl octanoate, octyldodecyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, myristyl myristate, decyl oleate, hexyldecyl dimethyloctanoate, cetyl lactate, myristyl lactate, lanolin acetate, isocetyl stearate, isocetyl isostearate, sucrose stearate, sucrose oleate, cholesteryl 12-hydroxystearate, ethylene glycol di-2-ethylhexylate, dipentaerythritol fatty acid ester, N-alkyl glycol monoisostearate, neopentyl glycol dicaprate, diisostearyl malate, glycerin di-2-heptylundecanoate, trimethylolpropane tri-2-ethylhexylate, trimethylolpropane triisostearate, pentane tetra-2-ethylhexylate, Lithritol, glycerin tri-2-ethylhexyl acid, trimethylolpropane triisostearate, cetyl 2-ethylhexanoate, 2-ethylhexyl palmitate, glycerin trimyristate, tri-2-heptylundecanoic acid glyceride, castor oil fatty acid methyl ester, oleic acid oil, cetostearyl alcohol, acetoglyceride, 2-heptylundecyl palmitate, cetyl palmitate, adipose Examples of the ethyl acetate include diisobutyl phosphate, N-lauroyl-L-glutamic acid-2-octyldodecyl ester, di-2-heptylundecyl adipate, ethyl laurate, di-2-ethylhexyl sebacate, 2-hexyldecyl myristate, 2-hexyldecyl palmitate, 2-hexyldecyl adipate, diisopropyl sebacate, 2-ethylhexyl succinate, ethyl acetate, butyl acetate, amyl acetate, and triethyl citrate.

[0111] Examples of silicone oils include chain polysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, and diphenylsiloxyphenyltrimethicone, and cyclic polysiloxanes such as pentasiloxane, decamethylpolysiloxane, dodecamethylpolysiloxane, and tetramethyltetrahydrogenpolysiloxane.

[0112] The oil used in the present invention may be a polar oil or a non-polar oil.

[0113] The lower limit of the content of emulsifier A in the O / W emulsion composition of the present invention is not particularly limited, but can be set to, for example, 0.1 mass% or more, preferably 0.5 mass% or more, more preferably 1 mass% or more, even more preferably 2 mass% or more, and even more preferably 3 mass% or more.

[0114] The upper limit of the content of emulsifier A in the O / W emulsion composition of the present invention is not particularly limited, but can be, for example, 10 mass % or less, preferably 7 mass % or less, more preferably 5 mass % or less, and even more preferably 4 mass % or less.

[0115] The lower limit of the content of emulsifier B in the O / W emulsion composition of the present invention is not particularly limited, but from the viewpoint of emulsion stability, it can be set to preferably 0.01 mass% or more, preferably 0.05 mass% or more, more preferably 0.1 mass% or more, even more preferably 0.2 mass% or more, even more preferably 0.3 mass% or more, and even more preferably 0.4 mass% or more.

[0116] The upper limit of the content of emulsifier B in the O / W emulsion composition of the present invention is not particularly limited, but from the viewpoint of suppressing stickiness during use, it can be preferably 2 mass % or less, more preferably 1 mass % or less, and even more preferably 0.5 mass % or less.

[0117] From the viewpoint of emulsion stability, the lower limit of the content mass ratio of emulsifier A to emulsifier B can be preferably 0.5 or more, more preferably 0.8 or more, even more preferably 1 or more, even more preferably 1.2 or more, even more preferably 1.5 or more, even more preferably 2 or more, even more preferably 2.5 or more, and even more preferably 3 or more.

[0118] From the viewpoint of emulsion stability, the upper limit of the content mass ratio of emulsifier A to emulsifier B is preferably 5 or less, more preferably 4.5 or less, even more preferably 4 or less, and still more preferably 3.5 or less.

[0119] The upper limit of the total content of emulsifiers other than emulsifier A in the O / W emulsion composition of the present invention is not particularly limited, but from the viewpoint of suppressing stickiness during use, it can be preferably 2 mass % or less, more preferably 1 mass % or less, and even more preferably 0.5 mass % or less.

[0120] The O / W emulsion composition of the present invention may contain any emulsifier other than emulsifier A and emulsifier B. In this case, the upper limit of the total content of emulsifiers other than emulsifier A and emulsifier B is not particularly limited, but from the viewpoint of suppressing stickiness during use, it can be preferably 1 mass % or less, more preferably 0.5 mass % or less, even more preferably 0.1 mass % or less, and even more preferably 0 mass %.

[0121] Furthermore, from the viewpoint of suppressing stickiness during use, the total content of the emulsifier in the O / W emulsion composition of the present invention can be preferably 10% by mass or less, more preferably 8% by mass or less, even more preferably 6% by mass or less, even more preferably 5% by mass or less, and even more preferably 4% by mass or less.

[0122] The constitution of the aqueous phase in the O / W emulsion composition of the present invention is not particularly limited, and may be, for example, a form containing a polyol in addition to water. Examples of polyols include polyethylene glycol, glycerin, 1,3-butylene glycol, erythritol, sorbitol, xylitol, maltitol, propylene glycol, dipropylene glycol, diglycerin, isoprene glycol, 1,2-pentanediol, 2,4-hexylene glycol, 1,2-hexanediol, and 1,2-octanediol. Of these, glycerin, 1,3-butylene glycol, and sorbitol are preferred. The content of the polyol is preferably 0.1 to 20% by mass, and more preferably 1 to 10% by mass, of the entire O / W emulsion composition.

[0123] In addition to the above-mentioned components, the O / W emulsion composition of the present invention may contain optional components that are generally used in cosmetics, provided that the effects of the present invention are not impaired. Examples of such optional components include moisturizing components such as sodium pyrrolidone carboxylate, lactic acid, and sodium lactate, powders such as mica, talc, kaolin, synthetic mica, calcium carbonate, magnesium carbonate, anhydrous silicic acid (silica), aluminum oxide, and barium sulfate, which may be surface-treated, inorganic pigments such as cobalt oxide, ultramarine, Prussian blue, and zinc oxide, which may be surface-treated, composite pigments such as iron oxide titanium dioxide sintered body, which may be surface-treated, pearling agents such as titanium mica, fish phosphorus foil, and bismuth oxychloride, which may be surface-treated, and pigments such as Red No. 202, Red No. 228, Red No. 226, Yellow No. 4, Blue No. 404, Yellow No. 5, Red No. 505, Red No. 230, Red No. 223, Orange No. 201, Red No. 213, and Yellow No. 214, which may be laked. Preferred examples of the organic pigments include Color No. 204, Yellow No. 203, Blue No. 1, Green No. 201, Purple No. 201, and Red No. 204; organic powders such as polyethylene powder, polymethyl methacrylate, nylon powder, and organopolysiloxane elastomer; lower alcohols such as ethanol and isopropanol; vitamin A or a derivative thereof, vitamin B group such as vitamin B6 hydrochloride, vitamin B6 tripalmitate, vitamin B6 dioctanoate, vitamin B2 or a derivative thereof, vitamin B12, and vitamin B15 or a derivative thereof; vitamin E group such as α-tocopherol, β-tocopherol, γ-tocopherol, and vitamin E acetate; and vitamins such as vitamin D, vitamin H, pantothenic acid, pantethine, and pyrroloquinoline quinone.

[0124] The method for producing the O / W emulsion composition of the present invention is not particularly limited, and the composition can be produced by a conventional method. That is, the O / W emulsion composition of the present invention can be produced by adding the oil phase components to the aqueous phase and mixing them with stirring. It is preferable that emulsifier A is dispersed in the aqueous phase before mixing with the oil agent, so that the water-soluble copolymer of emulsifier A spontaneously forms fine particles in the aqueous phase, and an O / W type emulsion composition can be prepared in which the fine particles are adsorbed to the emulsion interface.

[0125] The O / W emulsion composition of the present invention has a high oil phase content and therefore is compatible with other oily components, and is preferably used in cleansing cosmetics that remove oily stains, lipstick, foundation, and other makeup cosmetics.

[0126] The present invention also relates to a method for solving the problem of improving the emulsion stability of an emulsion composition emulsified with emulsifier A. That is, the present invention is a method for improving the emulsion stability of an emulsion composition emulsified with the above-mentioned emulsifier A, which is characterized by using the above-mentioned emulsifier B as an auxiliary. When preparing an emulsion composition emulsified with emulsifier A, the emulsion stability can be improved by blending an emulsifier as an auxiliary.

[0127] The type of emulsion composition emulsified with emulsifier A may be O / W type or W / O type, but the present invention is preferably applied to the O / W type emulsion composition. It is particularly preferable to apply the present invention to the O / W type emulsion composition having an oil content of 50% or more.

[0128] The lower limit of the content of emulsifier A in the emulsion composition prepared by applying the present invention is not particularly limited, but can be set to, for example, 0.1 mass% or more, preferably 0.5 mass% or more, more preferably 1 mass% or more, even more preferably 2 mass% or more, and even more preferably 3 mass% or more.

[0129] The upper limit of the content of emulsifier A in the emulsion composition prepared by applying the present invention is not particularly limited, but can be, for example, 10 mass % or less, preferably 7 mass % or less, more preferably 5 mass % or less, and even more preferably 4 mass % or less.

[0130] The auxiliary emulsifier B is used so that the lower limit of the content in the emulsion composition to be prepared is preferably 0.01 mass% or more, preferably 0.05 mass% or more, more preferably 0.1 mass% or more, even more preferably 0.2 mass% or more, even more preferably 0.3 mass% or more, and even more preferably 0.4 mass% or more.

[0131] From the viewpoint of preventing stickiness of the emulsion composition during use, it is preferable to use the emulsifier B as an auxiliary agent so that the upper limit of the content in the emulsion composition to be prepared is preferably 2% by mass or less, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less.

[0132] Emulsifier B, which is an auxiliary, is used so that the lower limit of the content mass ratio of emulsifier A to emulsifier B in the emulsion composition to be prepared is preferably 0.5 or more, more preferably 0.8 or more, even more preferably 1 or more, even more preferably 1.2 or more, even more preferably 1.5 or more, even more preferably 2 or more, even more preferably 2.5 or more, and even more preferably 3 or more.

[0133] Emulsifier B, which is an auxiliary, is used so that the upper limit of the content mass ratio of emulsifier A to emulsifier B in the emulsion composition to be prepared is preferably 5 or less, more preferably 4.5 or less, even more preferably 4 or less, and even more preferably 3.5 or less.

[0134] The upper limit of the total content of emulsifiers other than emulsifier A in the O / W emulsion composition of the present invention is not particularly limited, but from the viewpoint of suppressing stickiness during use, it can be preferably 2 mass % or less, more preferably 1 mass % or less, and even more preferably 0.5 mass % or less.

[0135] Any emulsifier other than emulsifier A and its auxiliary emulsifier, emulsifier B, may be used in combination. In this case, the upper limit of the total content of emulsifiers other than emulsifier A and emulsifier B in the emulsion composition to be prepared is not particularly limited, but from the viewpoint of suppressing stickiness during use, it can be preferably 1 mass % or less, more preferably 0.5 mass % or less, even more preferably 0.1 mass % or less, and even more preferably 0 mass %.

[0136] Furthermore, from the viewpoint of suppressing stickiness during use, the total content of the emulsifier in the emulsion composition to be prepared can be preferably 10% by mass or less, more preferably 8% by mass or less, even more preferably 6% by mass or less, even more preferably 5% by mass or less, and even more preferably 4% by mass or less.

[0137] Moreover, an embodiment may be used in which a polyol is used in combination with the emulsifier B. That is, in order to improve the emulsion stability of the emulsion composition emulsified with the emulsifier A, an embodiment may be used in which the emulsifier B and a polyol are used as auxiliary agents.

[0138] In the method for improving emulsion stability of the present invention, the types of emulsifier A, emulsifier B, and other components, as well as specific embodiments of the emulsion composition prepared by applying the present invention, can be directly applied to the items described above regarding the O / W emulsion composition. EXAMPLES

[0139] <Preliminary Examination> A hydrophilic monomer having the following structure and a hydrophobic monomer were copolymerized in a mass ratio of 7:3 to synthesize water-soluble copolymer 1 as emulsifier A. The weight average molecular weight of water-soluble copolymer 1 was measured by GPC in terms of polystyrene and found to be 61,000.

[0140] hydrophilic monomer [ka]

[0141] Hydrophobic Monomer [ka]

[0142] Aqueous solutions were prepared according to the formulations in Tables 1 and 2 below.

[0143] [Table 1]

[0144] [Table 2]

[0145] The dynamic interfacial tension was measured by the bubble pressure method for Samples 1 to 12 shown in Tables 1 and 2. The measurement by the bubble pressure method was carried out at a temperature of 25°C and a measurement interval of 10 to 20,000 ms (n=2). The obtained data of interfacial life and interfacial tension was plotted, and the slope of the graph was calculated and obtained as the adsorption rate data. Figure 1 shows a graph in which the adsorption rate is plotted on the vertical axis and the concentration of emulsifier A is plotted on the horizontal axis for samples 1 to 6. Figure 2 shows a graph in which the adsorption rate is plotted on the vertical axis and the mass content ratio of emulsifier A to emulsifier B is plotted on the horizontal axis for samples 7 to 12.

[0146] Furthermore, the interfacial tension was measured by the pendant drop method for Samples 1 to 12 shown in Tables 1 and 2. The measurement conditions for the pendant drop method were as follows. Temperature: 25℃ Oil phase: Chlopure OL, After droplet creation: Leave for 10 minutes Accumulation: 10 times every 30 seconds Kuropure OL density: 0.9135g / cm 3 Sample density: 1.007~1.008g / cm 3 (Actual measurement) Image analysis: Young Laplas

[0147] Figure 1 shows a graph in which the interfacial tension is plotted on the vertical axis and the concentration of emulsifier A on the horizontal axis for Samples 1 to 6. Figure 2 shows a graph in which the interfacial tension is plotted on the vertical axis and the mass content ratio of emulsifier A to emulsifier B on the horizontal axis for Samples 7 to 12.

[0148] Comparing Figure 1, which shows the results for a system containing emulsifier A (water-soluble copolymer 1) alone, with Figure 2, which shows the results for a system containing a combination of emulsifier A and emulsifier B (polyglycol fatty acid ester), a significant increase in the adsorption rate and a decrease in the interfacial tension were observed in the system containing emulsifier A and emulsifier B compared to the system containing emulsifier A alone. This result suggests that by combining emulsifier A and emulsifier B, an emulsion composition with excellent emulsion stability can be realized.

[0149] 2 in particular, a high adsorption rate and a low interfacial tension are observed when the content mass ratio of emulsifier A to emulsifier B is in the range of 1.5 to 4. This result suggests that an emulsion composition with particularly excellent emulsion stability can be realized when the content mass ratio of emulsifier A to emulsifier B is in the range of 1.5 to 4.

[0150] <Test Example> An O / W emulsion composition was prepared according to the formulation shown in Table 3. That is, the oil phase component and the aqueous phase component were mixed uniformly, and then the oil phase component was added dropwise to the aqueous phase component while stirring and mixing, thereby preparing an O / W emulsion composition.

[0151] [Table 3]

[0152] The prepared O / W emulsion compositions of Comparative Example 1 and Examples 1 to 9 were allowed to stand at room temperature for 1 hour, and the emulsified state after standing was evaluated. As a result, slight separation of the oil was observed in the O / W emulsion composition of Comparative Example 1 prepared using only water-soluble copolymer 1. On the other hand, in Examples 1 to 9, although the high internal phase O / W emulsion compositions had a high oil content, no separation of the oil was observed and a stable emulsified state was maintained. The above results show that the combination of emulsifier A and emulsifier B can provide a stable high internal phase O / W type emulsion composition.

[0153] Furthermore, the results of Examples 1 to 3 demonstrated that the emulsion stabilizing effect of the combination of emulsifier A and emulsifier B was exhibited regardless of the type of oil (polar oil, non-polar oil, silicone oil).

[0154] Furthermore, the emulsion stabilizing effect was exhibited even when the type and HLB of the nonionic surfactant were changed (Examples 4 to 6), and even when an ionic surfactant with significantly different properties was used, the emulsion stabilizing effect was exhibited (Example 7). This result shows that there is no limitation on the type of emulsifier B to be combined with emulsifier A.

[0155] As shown in Examples 8 and 9, in any formulation generally referred to as a high internal phase O / W type emulsion composition, the combination of emulsifier A and emulsifier B exhibits an emulsion stabilizing effect.

[0156] <Prescription Examples> By applying the present invention, for example, a cleansing cream having the following formulation can be provided. 1,3-BG 3 Ethylhexylglycerin 0.2 Pentaerythrityl tetraethylhexanoate 15 Isononyl isononanoate 10 Cetyl ethylhexanoate 28.26 Diphenylsiloxyphenyl Trimethicone 1 Cyclopentasiloxane 1 Squalane 1.15 Tocopherol 0.05 Phenoxyethanol 0.7 KT―TN 30% dispersion 3.3 PEG-12 isostearate 2 PEG-20 Glyceryl Isostearate 1 Polyglyceryl-10 Pentaisostearate 0.5 Wednesday 12.84 (mass%) [Industrial Applicability]

[0157] The O / W emulsion composition of the present invention can be used as a cleansing agent.

Claims

1. The emulsifier includes the following emulsifier A and emulsifier B; Emulsifier A: a water-soluble copolymer having, as essential structural units, one or more structural units (a) derived from a hydrophobic monomer represented by the following general formula (II), (I) or (III) and one or more structural units (b) derived from a hydrophilic monomer; Emulsifier B: an emulsifier different from the emulsifier A; An O / W type emulsion composition, characterized in that the content of an oil agent is 50 mass% or more. General formula (II) 【Chemistry 2】 (II) (R in general formula (II) ３ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; R ４ , R ５ may be the same or different, and each represents a branched acyl group not containing a ring structure and having 6 to 22 carbon atoms. X represents a group in which an OH group has been eliminated from a trihydric alcohol. General formula (I) 【Chemistry 1】 (I) (R in general formula (I) １ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; R ２ represents a branched hydrocarbon group having 13 to 30 carbon atoms and not containing a ring structure, or a hydrocarbon group having 6 to 12 carbon atoms and not containing a ring structure and having two or more branches. General formula (III) 【Chemistry 3】 (III) (R in general formula (III) ６ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; R ７ , R ８ , R ９ may be the same or different, and each represents a branched acyl group not containing a ring structure and having 6 to 22 carbon atoms. Y represents a group in which an OH group has been eliminated from a tetrahydric alcohol.

2. The O / W emulsion composition according to claim 1 , wherein the content of the oil agent is more than 70% by mass.

3. The O / W emulsion composition according to claim 1 or 2, wherein the total content of emulsifiers other than the emulsifier A is 1 mass% or less.

4. 3. The O / W emulsion composition according to claim 1, wherein the total content of the emulsifier is 4% by mass or less.

5. The O / W emulsion composition according to claim 1 or 2, wherein a content mass ratio of the emulsifier A to the emulsifier B is 1.5 to 4.

6. 3. The O / W emulsion composition according to claim 1, wherein the emulsifier B is a nonionic surfactant and / or an anionic surfactant.

7. The O / W emulsion composition according to claim 6 , wherein the nonionic surfactant is a lipophilic nonionic surfactant.

8. 7. The O / W emulsion composition according to claim 6, wherein the nonionic surfactant is a polyglycerol fatty acid ester and / or a polyoxyethylene alkyl ether.

9. The O / W emulsion composition according to claim 6 , wherein the anionic surfactant is a sulfate-based anionic surfactant.

10. A method for improving emulsion stability of an emulsion composition emulsified with an emulsifier A as follows:

1. A process, characterized in that the following emulsifier B is used as an auxiliary: Emulsifier A: A water-soluble copolymer having, as essential structural units, one or more structural units (a) derived from a hydrophobic monomer represented by the following general formula (II), (I) or (III), and one or more structural units (b) derived from a hydrophilic monomer. Emulsifier B: An emulsifier different from the emulsifier A. General formula (II) 【Chemistry 2】 (II) (R in general formula (II) ３ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; R ４ , R ５ may be the same or different, and each represents a branched acyl group not containing a ring structure and having 6 to 22 carbon atoms. X represents a group in which an OH group has been eliminated from a trihydric alcohol. General formula (I) 【Chemistry 1】 (I) (R in general formula (I) １ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; R ２ represents a branched hydrocarbon group having 13 to 30 carbon atoms and not containing a ring structure, or a hydrocarbon group having 6 to 12 carbon atoms and not containing a ring structure and having two or more branches. General formula (III) 【Chemistry 3】 (III) (R in general formula (III) ６ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; R ７ , R ８ , R ９ may be the same or different, and each represents a branched acyl group not containing a ring structure and having 6 to 22 carbon atoms. Y represents a group in which an OH group has been eliminated from a tetrahydric alcohol.

Images