WO2016182006A1

WO2016182006A1 - Copolymer

Info

Publication number: WO2016182006A1
Application number: PCT/JP2016/064071
Authority: WO
Inventors: 亘堀江; 雄一郎竹山; 恵加治; 厚志仁王; 萌露木; 紗弥香佐藤
Original assignee: ポーラ化成工業株式会社
Priority date: 2015-05-11
Filing date: 2016-05-11
Publication date: 2016-11-17
Also published as: CN111329787A; CN111481469A; AU2016261772A1; SG11201709288VA; AU2016261772B2; CN107614551A; TWI690541B; CN111329788B; CN111481469B; TW201708278A; CN111329788A; CN111358713B; CN111358713A; HK1243720A1; CN111329787B

Abstract

The present invention addresses the problem of providing a novel copolymer having an elastic feeling. A copolymer having a weight-average molecular weight of 20,000-110,000, having one or more types of constituent units (a) derived from a hydrophobic monomer having a specific structure, and one or more types of constituent units (b) derived from a hydrophilic monomer represented by general formula (2) as essential constituent units.

Description

Copolymer

The present invention relates to a novel copolymer which is a copolymer of a hydrophobic monomer and a hydrophilic monomer.

The present invention also relates to an emulsified composition emulsified with a water-soluble copolymer.

The present invention also relates to a skin cleanser containing a water-soluble copolymer.

The present invention also relates to a sunscreen cosmetic containing a water-soluble copolymer.

The present invention also relates to a coating film having a sea-island structure in which island particles of an amphiphilic copolymer are dispersed in an aqueous gel sea and a composition for forming the coating film.

Generally, oil agents are excellent in use feeling such as elasticity and moist feeling, and have been used for a long time as cosmetic materials. However, while the oil agent exhibits the above-mentioned excellent usability, if it is highly blended, it may become sticky and deteriorate the usability.

Under such circumstances, attempts have been made to reduce the stickiness caused by the oil by devising the composition and structure of the cosmetic. For example, Patent Document 1 proposes a technique for suppressing stickiness by reducing the particle size of an emulsified particle in the cosmetic composition.
However, the technique for reducing stickiness by devising the composition and structure of cosmetics as described in Patent Document 1 has a problem that the dosage form that can be applied is limited.

On the other hand, a new material that has both a moist feeling and a non-sticky feel has been proposed. For example, Patent Document 2 discloses a cosmetic base comprising an alkylene oxide derivative having both excellent feel and moisture retention.

An emulsion composition in which an oil phase component and an aqueous phase component are mixed with an emulsifier is widely used as a cosmetic dosage form. However, general low molecular weight emulsifiers may cause problems such as irritation to the skin and stickiness.
In order to solve such problems, various emulsification techniques using a polymer emulsifier have been recently proposed.

Patent Document 3 discloses an emulsified composition using hydroxyethyl cellulose as an emulsifier.
Patent Document 4 discloses an emulsified composition using an alkyl-modified carboxyvinyl polymer as an emulsifier.

Furthermore, conventionally, in skin cleansing agents such as facial cleansers, potassium salts of higher fatty acids have been frequently used because of their good foaming, good detergency, and refreshing feeling after washing. However, skin cleansing agents based on potassium salts of higher fatty acids have such excellent properties, but on the other hand, it is difficult to obtain creamy foam quality, and the skin is easily degreased by washing, Also, there was a problem that the soap residue (scum) remained on the skin, and the skin was easily pulled after use.

As a method for improving such problems, combined use of higher fatty acids and surfactants such as acyl taurine salt type, acyl isethionate type, phosphate ester type, acyl amino acid type (for example, Patent Document 5), other than surfactants (For example, Patent Documents 6 to 12) and the like have been proposed (for example, silicone compounds, specific glycolipids, raffinose, plant seed mucilage, various polymer compounds, etc.).
Attempts have also been made to improve the above problems by combining an acylglycine surfactant and a specific polymer compound without using a higher fatty acid potassium salt as a main component (see Patent Document 13).

Furthermore, oil-in-water emulsified sunscreen cosmetics have a refreshing feel and are easy to use continuously. In order to enhance the ultraviolet protection effect, the oil-in-water emulsion cosmetics use an ultraviolet absorber or an ultraviolet scattering agent that is a metal oxide powder such as zinc oxide or titanium oxide. However, when a large amount of ultraviolet absorber is blended, there is a problem that discoloration occurs and the feeling of use such as poor spread and stickiness is deteriorated. In addition, when a large amount of metal oxide powder is blended, there is a problem that not only the powder aggregates and settles with time, but also the stability with time such as viscosity reduction, emulsification separation, and precipitation decreases. When these are used in combination, the above problem tends to occur more easily.

In order to improve these problems, it has been proposed to use an ultraviolet absorber such as a dibenzoylmethane derivative and titanium oxide treated with silane and / or silicone (see Patent Document 14).
In addition, oil-in-water emulsified cosmetics using water-soluble polymers such as polyacrylic acid amide, xanthan gum, (sodium acrylate / acryloyldimethyltaurine) copolymer have been proposed (see Patent Documents 15 and 16).

The sea-island structure means that two types of incompatible polymers cause phase separation, and a continuous phase (sea phase) containing one polymer is dispersed in a dispersed phase (island phase) containing the other polymer. It refers to the existing structure. As described above, the sea-island structure has a heterogeneous structure in which phases are separated, and thus has a different property from a composition having a uniform structure. To take advantage of these properties, sea-island structures are actively researched and developed in the technical fields of plastics, rubber, toner, adhesives, and the like.
For example, Patent Document 17 discloses a tire coated with a coating mixture having a sea-island structure including a sea phase containing a thermoplastic resin and an island phase containing a polyurethane-based thermoplastic elastomer.
However, no attempt has been made to use the sea-island structure in the cosmetics field.

By the way, Patent Document 18 discloses a skin external application containing an amphiphilic copolymer having a structural unit derived from a specific hydrophobic acrylic ester monomer and a structural unit derived from a specific hydrophilic acrylic monomer. Agents are disclosed.

JP 2012-116783 A No. 2006/038724 JP 2011-231049 JP 09-019631 A JP-A-6-248298 Japanese Patent Laid-Open No. 10-77206 JP 2001-72574 A JP 2000-178172 A Japanese Patent Laid-Open No. 11-209799 JP 2003-73257 A JP 2007-277140 A Japanese Patent Laid-Open No. 10-183193 JP-A-9-78082 Japanese Patent Laid-Open No. 9-2929 JP 2003-104859 A JP 2010-215602 A JP 2013-180652 A JP 2014-9189 A

As described above, the oil agent has a preferable feeling of use such as a feeling of elasticity, but also has problems such as stickiness. Under such circumstances, there has been a demand for a new material having elasticity such as an oil agent.
An object of the present invention is to provide a novel copolymer having elasticity. Moreover, in the preferable form of this invention, it is set as the 1st subject to provide the copolymer which is hard to produce stickiness and has a moist feeling further.

In addition, the above-mentioned polymer emulsifier has less irritation to the skin, and has advantages such as less stickiness when contained at a low concentration, but is inferior in emulsifying power compared to conventional low-molecular emulsifiers. there were. Therefore, in order to ensure the stability of the emulsified state, it is necessary to highly blend the polymer emulsifier in the emulsified composition so as to have a high viscosity.

In view of such a situation, a second object of the present invention is to provide an emulsified composition having excellent emulsification stability while having less irritation to the skin and less stickiness.

Due to increasing consumer needs in recent years, these methods are not satisfactory in particular with respect to foam quality and feel after washing, and further improvements have been desired.

In view of such a situation, a third problem to be solved by the present invention is to provide a new technique for reducing the feeling of tightness of the skin after using the skin cleansing material.
In addition, after use without impairing the advantageous effects of the original skin cleansing agents such as detergency, good foaming, good foam quality, no feeling of slimming after use, ease of spreading to the skin, etc. A fourth problem is to provide a technique for reducing the feeling of skin tightness.

Furthermore, in the technical field of oil-in-water sunscreen cosmetics, it has been a challenge to achieve both an ultraviolet protection function and a feeling of use and emulsion stability. Conventionally, various techniques have been proposed to solve this problem, but it has been insufficient.
In view of such circumstances, the fifth problem to be solved by the present invention is that it has an excellent UV protection function, but is excellent in use feeling such as no stickiness and moisturizing feeling, and has emulsion stability. It is to provide an oil-in-water sunscreen cosmetic.

The problem to be solved by the present invention is to provide a film having a sea-island structure mainly composed of a water-soluble component and a technique for forming the film. It is another object of the present invention to provide a technique for imparting a milk-like feel containing an oil agent to a film mainly composed of a water-soluble component. It is a sixth object of the present invention to provide a film that preferably has both moisture retention and flexibility and a technique for forming the film.

In light of the situation that is the background of the first problem, the present inventors have intensively studied for an elastic copolymer, and as a result, have a hydrophobic, polymerizable carboxyl group and two specific branched structures. A copolymer obtained by polymerizing an acrylic ester monomer having an acyl group and a hydrophilic acrylic monomer having a specific structure has excellent solubility, particularly water solubility, and has an elastic feel like an oil agent. The headline, the present invention has been reached. That is, the present invention is as follows.

One or two or more structural units (a) derived from a hydrophobic monomer represented by the following general formula (1) and one or two structural units derived from a hydrophilic monomer represented by the following general formula (2) A copolymer having a weight average molecular weight of 20,000 to 110,000, comprising at least a constituent unit (b) as an essential constituent unit.

General formula (1)

(1)
(In the general formula (1), R1 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R2 and R3 may be the same or different, have no ring structure, have a branched structure and have 6 to 22 carbon atoms. X represents a group in which an OH group is eliminated from a trivalent alcohol.)

General formula (2)

(2)
(In the general formula (2), R4 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R5 represents an alkylene group having 2 to 4 carbon atoms which may have a hydroxyl group, and R6 represents a hydrogen atom or carbon atom. And represents 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, and n represents an integer of 6 to 40.)

Such a copolymer has a feeling of elasticity when applied to the skin, and has a non-sticky and moist feeling.

In a preferred embodiment of the present invention, the mass ratio of the structural unit (a) to the structural unit (b) is 25:75 to 35:65.
A copolymer having a mass ratio of the structural unit (a) to the structural unit (b) in the above range is excellent in elasticity and non-stickiness.

In a preferred embodiment of the present invention, the molar ratio of the structural unit (a) to the structural unit (b) is 35:65 to 46:54.
A copolymer having a mass ratio of the structural unit (a) to the structural unit (b) in the above range is excellent in elasticity and non-stickiness.

In a preferred embodiment of the present invention, the hydrophobic monomer is a hydrophobic monomer represented by the following general formula (3).

General formula (3)

(3)
(In the general formula (3), R7 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R8 and R9 may be the same or different, have no ring structure, have a branched structure and have 10 to 22 carbon atoms. Or an acyl group having 6 to 9 carbon atoms and having 2 or more branches that does not contain a ring structure, and Y represents a group in which an OH group is eliminated from a trivalent alcohol.

By using the monomer as a hydrophobic monomer, a copolymer having a better feel can be obtained.

In a preferred embodiment of the present invention, the hydrophilic monomer is a hydrophilic monomer represented by the following general formula (4).

General formula (4)

(4)
(In the general formula (4), R10 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R11 represents a hydrogen atom, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or an aliphatic hydrocarbon having 1 to 14 carbon atoms. Group or an acyl group having 1 to 12 carbon atoms, m represents an integer of 6 to 40)

By using the above monomer as the hydrophilic monomer, a copolymer having a better feel can be obtained.

In a preferred embodiment of the present invention, the trihydric alcohol is glycerin, trimethylolpropane, or trimethylolethane.
By adopting such a form, the feeling of elasticity can be improved.

The hydrophobic monomer is a compound represented by the following general formula (5).

General formula (5)

(5)
(In general formula (5), R12 and R13 may be the same or different and each represents a branched acyl group having 18 carbon atoms that does not contain a ring structure.)

The elasticity can be improved by using such a hydrophobic monomer.

In a preferred embodiment of the present invention, the hydrophilic monomer is a hydrophilic monomer represented by the following general formula (6).

General formula (6)

(6)
(In general formula (6), l represents an integer of 6 to 40.)

The elasticity can be improved by using such a hydrophilic monomer.

The present invention also relates to a skin external preparation containing the above-mentioned copolymer of the present invention. Such an external preparation for skin has a feeling of elasticity after being applied to the skin. In addition, it is excellent in no stickiness and moist feeling.

This invention which solves the 2nd subject is 1 type, or 2 or more types of structural units (c) induced | guided | derived from the hydrophobic monomer represented by the said general formula (1), the following general formula (7), or (8). And a water-soluble copolymer having one or more structural units (d) derived from a hydrophilic monomer as essential structural units, and substantially free of an emulsifier other than the water-soluble copolymer. The emulsified composition is characterized.

General formula (7)

(7)
(In the general formula (7), R14 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R15 does not include a branched hydrocarbon group that does not include a ring structure having 13 to 30 carbon atoms, or does not include a ring structure. Represents a hydrocarbon group having 6 to 12 carbon atoms having two or more branches.)

General formula (8)

(8)
(In the general formula (8), R16 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R17, R18, and R19 may be the same or different, have no ring structure, have a branch, and have 6 carbon atoms. Represents an acyl group of ˜22, Y represents a group in which an OH group is eliminated from a tetravalent alcohol.

The emulsified composition of the present invention has little stickiness during use by including the water-soluble copolymer.

In a preferred embodiment of the present invention, the hydrophilic monomer is a polymerizable carboxylic acid, a hydrophilic monomer represented by the general formula (2), a hydrophilic monomer represented by the following general formula (9), the following general formula ( 10) or one or more hydrophilic monomers selected from the group consisting of the hydrophilic monomer represented by the following general formula (11).

General formula (9)

(9)
(In the general formula (9), R20 represents a hydrogen atom or a methyl group.)

General formula (10)

(10)
(In the general formula (10), R21 represents a hydrogen atom or a methyl group, G—O— represents a group obtained by removing hydrogen from the hydroxyl group at the 1-position of the reducing sugar, m is 2 or 3, and l is 1-5. Represents an integer.)

Formula (11)

(11)
(In general formula (11), R22 represents a hydrogen atom or a methyl group, R23 represents an amino acid residue, a polyamine residue or an amino alcohol residue. Q represents an oxygen atom or a group represented by NH.)

By including a water-soluble copolymer containing the structural unit (d) derived from such a hydrophilic monomer, stickiness during use of the emulsion composition of the present invention can be further reduced.

In a preferred embodiment of the present invention, the hydrophobic monomer is a hydrophobic monomer represented by the general formula (1), and the water-soluble monomer is a hydrophilic monomer represented by the general formula (2).
Such a water-soluble copolymer having a structural unit derived from a hydrophobic monomer and a hydrophilic monomer is excellent in emulsifying power and excellent in the effect of reducing stickiness during use of the emulsified composition of the present invention.

In a preferred embodiment of the present invention, the content of the water-soluble copolymer is 0.5 to 30% by mass.
By setting the content of the water-soluble copolymer in the above range, the stability of the emulsion composition can be improved.

In a preferred embodiment of the present invention, the content of the oil phase component is 0.1 to 70% by mass.
The emulsion composition of the present invention in which the content of the oil phase component is in the above range is excellent in stability.

Since the emulsified composition of the present invention has little stickiness, it is preferably a cosmetic.

Further, the present invention is derived from one or more structural units (c) derived from the hydrophobic monomer represented by the general formula (1), (7) or (8) and a hydrophilic monomer. The present invention also relates to an emulsifier composed of a water-soluble copolymer having one or two or more structural units (d) as essential structural units.
Such an emulsifier has excellent emulsifying power while being mild.

The present invention also relates to a method for producing an emulsified composition comprising a step of emulsifying using the emulsifier, wherein the emulsifier other than the emulsifier is substantially not used. .
According to such a method, it is possible to easily produce an emulsified composition without using a conventional emulsifier that can cause stickiness and without adding a high amount of emulsifier.

In the present invention for solving the third and fourth problems, one or more structural units derived from the hydrophobic monomer represented by the general formula (1), (7) or (8) (e And a water-soluble copolymer having one or more structural units (f) derived from hydrophilic monomers as essential structural units.

The skin cleansing material of the present invention includes the above-mentioned water-soluble copolymer, thereby realizing a reduction in the feeling of sticking after use while providing good foaming and creamy foam quality.

In a preferred embodiment of the present invention, the hydrophilic monomer is a polymerizable carboxylic acid, a hydrophilic monomer represented by the general formula (2), a hydrophilic monomer represented by the general formula (9), or the general formula ( The hydrophilic monomer represented by 10) and one or more hydrophilic monomers selected from the group consisting of the hydrophilic monomer represented by the general formula (11).

By including a water-soluble copolymer containing the structural unit (e) derived from such a hydrophilic monomer, it is possible to further reduce the feeling of tension after use of the skin cleansing agent of the present invention.

In a preferred embodiment of the present invention, the hydrophobic monomer is a hydrophobic monomer represented by the general formula (1), and the water-soluble monomer is a hydrophilic monomer represented by the general formula (2).
By including a water-soluble copolymer having a structural unit derived from such a hydrophobic monomer and a hydrophilic monomer, it is possible to further reduce the feeling of tension after use of the skin cleansing agent of the present invention.

In an embodiment of the present invention, the content of the water-soluble copolymer is 0.1 to 20% by mass.
By setting the content of the water-soluble copolymer in the above range, it is possible to reduce the slimy feeling when using the skin cleanser of the present invention.

The present invention is preferably applied to a foaming cleaning material.
According to the present invention, it is possible to reduce the feeling of tightness of the skin after use without hindering the foaming and foam quality of the foaming detergent.

The present invention is preferably applied to a gel-like skin cleansing material.
ADVANTAGE OF THE INVENTION According to this invention, the feeling of tightness of the skin after use can be reduced, improving the ease of extending to the skin of a gel-like skin cleansing material.

¡Skin cleansing agents containing surfactants have a relatively strong detergency, so they feel strong after use. Therefore, it is preferable to apply this invention to the skin cleansing agent of the form containing surfactant. According to the present invention, it is possible to reduce the feeling of tightness of the skin after using the skin cleansing agent without impairing or improving the excellent cleaning power of the surfactant.

The skin cleanser containing fatty acid soap has good foaming, creamy foam quality and excellent cleaning power, but it gives a strong feeling of tension after use. Therefore, it is preferable to apply this invention to the skin cleansing agent of the form containing a fatty acid soap. ADVANTAGE OF THE INVENTION According to this invention, the feeling of firmness of the skin after use can be reduced, without impairing the advantageous effect which the skin cleansing agent containing fatty acid soap has.

In a preferred embodiment of the present invention, the content ratio of the water-soluble copolymer to the fatty acid soap is 1: 500 to 1: 2, preferably 1: 200 to 1: 3, more preferably 1: 100 to 1: 5. It is.
By making content of the said water-soluble copolymer into the said range, the feeling of tension after use of the skin cleansing agent containing fatty acid soap can be reduced more effectively.

The present invention is also preferably applied to a skin cleanser containing a nonionic surfactant.
ADVANTAGE OF THE INVENTION According to this invention, the feeling of firmness of the skin after use can be reduced, improving the detergency of the skin cleansing agent containing a nonionic surfactant.

In a preferred embodiment of the present invention, the content ratio of the water-soluble copolymer and the nonionic surfactant is 1:20 to 1: 0.5, preferably 1:15 to 1: 0.7, more preferably Is from 1:10 to 1: 1.
By making the ratio of the content of the water-soluble copolymer and the nonionic surfactant within the above range, the feeling of tension after use can be more effectively reduced.

The present invention for solving the fifth problem is an oil-in-water sunscreen cosmetic comprising components (A) to (D).
(A) One or more structural units (g) derived from the hydrophobic monomer represented by the general formula (1), (7) or (8), and 1 derived from a hydrophilic monomer A water-soluble copolymer having a seed or two or more structural units (h) as essential structural units (B) One molecule of polyglycerol having a polymerization degree of 10 and 2 to 5 molecules of fatty acids having 16 or more carbon atoms are ester-condensed Polyglycerin fatty acid ester (C) ionic surfactant (D) UV scattering agent and / or UV absorber

The sunscreen cosmetics of the present invention have a UV protection function and are less sticky and excellent in moisture retention. Moreover, the sunscreen cosmetic of the present invention has emulsion stability.

By using a water-soluble copolymer containing the structural unit (h) derived from such a hydrophilic monomer, it is possible to improve the feeling of use such as less stickiness and moisturizing feeling.

In a preferred embodiment of the present invention, the hydrophobic monomer is a hydrophobic monomer represented by the general formula (1), and the water-soluble monomer is a hydrophilic monomer represented by the general formula (2).
A sunscreen cosmetic containing a water-soluble copolymer having a structural unit derived from a hydrophobic monomer and a hydrophilic monomer has a better feeling of use.

In a preferred embodiment of the present invention, the component (C) is an anionic surfactant.
By using an anionic surfactant as the ionic surfactant, the emulsion stability can be further improved. Moreover, the sunscreen cosmetics of the present invention using an anionic surfactant are also excellent in use feeling.

In a preferred form of the invention, the anionic surfactant is sodium acyl lactate.
By using sodium acyl lactate as the anionic surfactant, the emulsion stability can be further improved. In addition, the sunscreen cosmetic of the present invention using sodium acyl lactate is excellent in the feeling of use.

In a preferred embodiment of the present invention, the component (B) is polyglyceryl-10 pentastearate.
The sunscreen cosmetic of the present invention containing polyglyceryl-10 pentastearate is excellent in emulsion stability and feeling of use.

In a preferred embodiment of the present invention, the component (D) is a water-dispersible ultraviolet scattering agent.
Since the water-dispersible ultraviolet scattering agent is uniformly dispersed in the aqueous phase, the sunscreen cosmetic in such a form is excellent in the ultraviolet protection function.

In a preferred embodiment of the present invention, the water-dispersible ultraviolet scattering agent is an ultraviolet scattering agent that has been surface-treated with sodium polyacrylate.
In such a form of sunscreen cosmetic, the UV scattering agent is more uniformly dispersed, and the UV protection function is excellent.

The present invention that solves the sixth problem includes one or more structural units (i) derived from a hydrophobic monomer and one or more structural units (j) derived from a hydrophilic monomer. ) As an essential constituent unit, a water-soluble polymer and / or a salt thereof, and water,
A composition having a sea-island structure in which island particles containing the amphiphilic copolymer are dispersed in an aqueous gel formed by the water-soluble polymer and / or a salt thereof by evaporation of the water. It is a thing.

The film has a sea-island structure mainly composed of water-soluble components, and has a touch like milk containing an oil. According to the composition of the present invention, a film having such a sea-island structure can be formed on the skin.

In a preferred embodiment of the present invention, the average major axis / minor axis ratio of the island particles is 0.8 or more, and the number particle size distribution of the island particles having an average particle diameter of 1 to 5 μm is 80% or more.
The coating film having such structural characteristics is excellent in moisture retention and flexibility.
And the film which has such an outstanding property can be easily formed by apply | coating the composition of this invention to skin.

In a preferred embodiment of the present invention, the water-soluble polymer is one or more water-soluble polymers selected from the group consisting of an acrylic acid-based water-soluble polymer, a water-soluble polypeptide and a water-soluble polysaccharide and / or its It is salt.
By setting it as the form containing such a water-soluble polymer, the water-solubility of the component of a composition can be improved, and stability of a composition can be improved by suppressing generation | occurrence | production of precipitation.

In a preferred embodiment of the present invention, the water-soluble polymer is selected from the group consisting of sodium polyacrylate, (acrylates / alkyl acrylate (C10-30)) crosspolymer, sodium polyglutamate, xanthan gum and white jellyfish polysaccharide 1 It is a seed or two or more water-soluble polymers.
By setting it as the form containing such a water-soluble polymer, stability of a composition can be improved more.

In a preferred form of the invention, the composition comprises a polyol that promotes phase separation between the aqueous gel and the amphiphilic copolymer and / or a polyol that inhibits phase separation between the aqueous gel and the amphiphilic copolymer.
By including such a polyol, the uniformity of the film can be improved.

In a preferred embodiment of the present invention, the polyol that promotes phase separation is a polyol that increases the cloud point of the aqueous solution by mixing with an aqueous solution of a nonionic surfactant having a polyether chain in the hydrophilic portion. ,
The polyol that suppresses phase separation is a polyol that lowers the cloud point of an aqueous solution by mixing with an aqueous solution of a nonionic surfactant having a polyether chain in a hydrophilic portion.
By including such a polyol, the uniformity of the film can be improved.

In a preferred embodiment of the present invention, the polyol for promoting phase separation is one or more polyols selected from the group consisting of 1,3-butylene glycol and polyethylene glycol.
By using such a polyol, phase separation between the aqueous gel and the amphiphilic copolymer can be effectively promoted, and the uniformity of the coating film can be improved.

In a preferred embodiment of the present invention, the polyol that suppresses phase separation is one or more polyols selected from the group consisting of glycerin, diglycerin, sorbitol, and maltitol.
By using such a polyol, phase separation between the aqueous gel and the amphiphilic copolymer can be effectively promoted, and the uniformity of the coating film can be improved.

In a preferred embodiment of the present invention, the mass ratio of the total amount of the polyol that promotes phase separation and the polyol that suppresses phase separation to the total amount of the amphiphilic copolymer and the water-soluble polymer is 5: 1 to 20: 1.
By setting it as such a form, the uniformity of the said film can be improved.

In a preferred embodiment of the present invention, the mass ratio of the polyol that promotes phase separation and the polyol that inhibits phase separation is 3.5: 1 to 1: 2.5.
By setting it as such a form, the uniformity of the said film can be improved.

In a preferred embodiment of the present invention, the content of the amphiphilic copolymer is 0.1 to 5% by mass.
By setting the content of the amphiphilic copolymer in the above range, it is possible to obtain a composition capable of forming the coating film having a more flexible feel.

In the preferable form of this invention, content of an oil agent is 1 mass% or less.
By setting it as such a form, it can be set as the composition which can form the said film with little stickiness.

In a preferred embodiment of the present invention, the amphiphilic copolymer includes one or more copolymers selected from the following group E.

Group E: Polyquaternium-51, Polyquaternium-61, (glyceryl amidoethyl methacrylate / stearyl methacrylate) copolymer, and a structure derived from a hydrophobic monomer selected from the above general formulas (1), (7), (8) Acrylic acid amphiphilic copolymer containing unit (i)

The composition of the present invention containing such an amphiphilic copolymer has a stronger feel like milk and can form the above-described coating film with better flexibility.

In a preferred embodiment of the present invention, the acrylic acid-based amphiphilic copolymer contains a structural unit (j) derived from one or more hydrophilic monomers selected from the following group F.

Group F: polymerizable carboxylic acid, copolymer represented by general formula (2), copolymer represented by general formula (9), copolymer represented by general formula (10), and general formula (11) Copolymer represented by

The composition of the present invention containing the amphiphilic copolymer having the structural unit (j) derived from such a hydrophilic monomer can form the above-described film excellent in the touch like milk and flexibility. it can.

In a preferred embodiment of the present invention, the acrylic acid-based amphiphilic copolymer is represented by the structural unit (i) derived from the hydrophobic monomer represented by the general formula (1) and the general formula (2). A structural unit (j) derived from a hydrophilic monomer.
According to the composition of the present invention containing such an acrylic acid-based amphiphilic copolymer, it is possible to form the coating film with better moisture retention and flexibility.

Further, the present invention is a film having a sea-island structure in which island particles containing an amphiphilic copolymer are dispersed in an aqueous gel formed by a water-soluble polymer,
The amphiphilic copolymer essentially comprises one or more structural units (i) derived from a hydrophobic monomer and one or more structural units (j) derived from a hydrophilic monomer. It also relates to a coating characterized by having as a unit.

The film of the present invention has a sea-island structure mainly composed of water-soluble components. And although it has a water-soluble component as a main component, it feels like milk containing an oil.

In a preferred embodiment of the present invention, the average major axis / minor axis ratio of the island particles is 0.8 or more, and the number particle size distribution of the island particles having an average particle diameter of 1 to 5 μm is 80% or more.
The coating having such a structural characteristic is excellent in the touch like milk containing an oil agent.

The present invention also provides a method for forming the above-described film of the present invention,
An amphiphilic copolymer having one or more structural units (i) derived from a hydrophobic monomer and one or more structural units (j) derived from a hydrophilic monomer as essential structural units And a method comprising applying to the skin a composition comprising a water-soluble polymer and / or a salt thereof and water.
According to the method of the present invention, the coating film can be easily formed.

In a preferred embodiment of the present invention, the composition comprises a polyol that promotes phase separation between the amphiphilic copolymer and the aqueous gel and / or a polyol that suppresses phase separation between the aqueous gel and the amphiphilic copolymer. Including.
By using an aqueous solution containing such a polyol, the film having excellent uniformity can be formed.

According to the present invention, a copolymer having a feeling of elasticity and an external preparation for skin can be provided.

Further, according to the present invention, it is possible to provide an emulsified composition having excellent emulsification stability while having little irritation to the skin and less stickiness.

Further, according to the present invention, it is possible to provide a skin cleanser with reduced feeling of tension after use.
In addition, when the present invention is applied to a skin cleanser containing a fatty acid soap, it is possible to reduce the feeling of tension after use without inhibiting good-quality foaming and creamy foam quality.
Moreover, even if it is a case where this invention is applied to a gel-like skin cleansing agent, the effect of reducing the feeling of tension after use can be obtained.

In addition, according to the present invention, an oil-in-water sunscreen cosmetic that has an excellent UV protection function, is excellent in use feeling such as no stickiness and moisturizing feeling, and has emulsion stability. Can do.

In addition, according to the present invention, it is possible to provide a film having a sea-island structure mainly composed of a water-soluble component and a technique for forming the film. The coating film has a milk-like feel including an oil agent, despite being mainly composed of water-soluble components.
Moreover, in the preferable form of this invention, the technique which forms the said coating film and this coating film without stickiness can be provided.

It is a bar graph showing the evaluation result of the gel cosmetics containing the copolymer of Example 1 and Comparative Example 1. FIG. 3 shows a three-component phase diagram in which blending ratios of (glyceryl diisostearate methacrylate / methoxymethoxymethacrylate PEG-23) copolymer, squalane and water in Examples 9 to 31 are plotted. FIG. 3 shows a three-component phase diagram in which the blending ratio of (glyceryl diisostearate methacrylate / methoxymethoxymethacrylate PEG-23) copolymer, tri (caprylic acid / capric acid) glyceryl and water in Examples 32-62 is plotted. FIG. 3 shows a three-component phase diagram in which blending ratios of (glyceryl diisostearate methacrylate / methoxymethoxy methacrylate PEG-23) copolymer, dimethicone and water in Examples 63 to 89 are plotted. The three-component phase diagram of the total amount of 1,3-butylene glycol, glycerin, xanthan gum and (methoxy methacrylic acid PEG-23 / glyceryl diisostearate) copolymer contained in Examples 104 to 124 is shown. The photomicrographs of the compositions of Examples 105, 106, 108, 111, 113, 114, 115, 119, 120, 122, 123 are shown. The pie chart showing the result of the touch evaluation of the composition of Example 104 in Test Example 7 is shown.

The copolymer of the present invention that solves the first problem includes one or more structural units (a) derived from the hydrophobic monomer represented by the general formula (1), and the general formula (2). One or more structural units (b) derived from the hydrophilic monomer represented are included as essential structural units.
In the present invention, the “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 (1) and the hydrophilic monomer represented by the general formula (2) will be described.

<1> Hydrophobic Monomer The copolymer of the present invention is a kind of structural unit derived from the hydrophobic monomer represented by the general formula (1) (hereinafter sometimes simply referred to as “structural unit (1)”). Alternatively, two or more kinds are contained as essential constituent units.

Here, examples of the alkyl group represented by R1 include a methyl group, an ethyl group, a propyl group, an isopropyl group, and a cyclopropyl group. In the present invention, R1 is preferably a hydrogen atom or a methyl group.

Examples of the branched acyl group having 6 to 22 carbon atoms that does not include the ring structure represented by R2 and R3 include a 2-methylpentanoyl group, a 3-methylpentanoyl group, a 4-methylpentanoyl group, 2-ethylbutanoyl group, 2-ethylbutanoyl group, 2,2-dimethylbutanoyl group, 3,3-dimethylbutanoyl group, 2-methylhexanoyl group, 4-methylhexanoyl group, 5-methylhexanoyl group Noyl group, 2,2-dimethylpentanoyl group, 4,4-dimethylpentanoyl group, 2-methylheptanoyl group, 2-ethylhexyl group, 2-propylpentanoyl group, 2,2-dimethylhexanoyl group, 2 , 2,3-trimethylpentanoyl group, 2-methyloctanoyl group, 3,3,5-trimethylhexanoyl group, 2-methylnonanoyl group, 4-methylno Noyl 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 Group, 2,2 dimethyldecanoyl group, 2-ethyldecanoyl group, 2-butyloctanoyl group, diethyloctanoyl group, 2-tert-butyl-2,2,4-trimethylpentanoyl group, 10-methyldodecane Noyl 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 Group, 2-butyldodecanoyl group, 2-hexyldecanoyl group, 16-methylheptadecanoyl group, 2,2-dimethylhexanoyl group, 2-butylhexadecanoyl group, 2-hexyldecanoyl group, 2, Examples include 4,10,14-tetramethylpentanoyl group, 18-methylnonadecanoyl group, 3,7,11,15-tetra-methylhexadecanoyl group, 19-methyleicosanoyl group and the like. .

In a more preferred embodiment of the present invention, the hydrophobic monomer represented by the general formula (1) is a hydrophobic monomer represented by the general formula (3).

Such a branched acyl group having 10 to 22 carbon atoms which does not contain a ring structure and is represented by R8 and R9 in a preferred embodiment includes a 2-methylnonanoyl group, a 4-methylnonanoyl group, and an 8-methylnonanoyl group. 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, 2-dimethyldecanoyl group, 2-ethyldecanoyl group, 2-butyloctanoyl group, diethyloctanoyl group, 2-tert-butyl- , 2,4-trimethylpentanoyl group, 10-methyldodecanoyl group, 3-methyldodecanoyl group, 4-methyldodecanoyl group, 11-methyldodecanoyl group, 10-ethylundecanoyl group, 12-methyltri Decanoyl group, 2-butyldecanoyl group, 2-hexyloctanoyl group, 2-butyl-2-ethyloctanoyl group, 12-methyltetradecanoyl group, 14-methylpentadecanoyl group, 2-butyldodecanoyl group Group, 2-hexyldecanoyl group, 16-methylheptadecanoyl group, 2,2-dimethylhexanoyl group, 2-butylhexadecanoyl group, 2-hexyldecanoyl group, 2,4,10,14-tetra Methylpentanoyl group, 18-methylnonadecanoyl group, 3,7,11,15-tetra-methylhexadecanoyl group, 1 Examples thereof include a 9-methyleicosanoyl group.

Further, in the preferred embodiment, the acyl group having 6 to 9 carbon atoms having 2 or more branches and containing no ring structure represented by R8 and R9 includes a 2,2-dimethylbutanoyl group, 3, 3-dimethylbutanoyl group, 2,2-dimethylpentanoyl group, 4,4-dimethylpentanoyl group, 2,2-dimethylhexanoyl group, 2,2,3-trimethylpentanoyl group, 3,5,5 -A trimethylhexanoyl group etc. can be illustrated.

The carbon number of the acyl group of R8 and R9 in the general formula (3) is preferably 12 to 22, more preferably 14 to 20, and still more preferably 16 to 20.
Further, the number of carbon atoms in the main chain of the acyl group of R8 and R9 in the general formula (3) is preferably 9 to 21, more preferably 12 to 20, and still more preferably 16 to 18.
The number of branches in the acyl group of R8 and R9 in the general formula (3) is preferably 1 to 3, more preferably 1 or 2, and still more preferably 1.
Furthermore, in the acyl group of R8 and R9 in the general formula (3), the position number of the carbon in the main chain to which the branched chain is bonded is preferably as large as possible. Specifically, the branched chain is bonded to the carbon at the end of the main chain, preferably from the 1st to 3rd carbon, more preferably the 1st or 2nd carbon, and even more preferably the 1st carbon. It is preferable.

Specific examples of R8 and R9 include 10-methylundecanoyl group, 10-methyldodecanoyl group, 11-methyldodecanoyl group, 10-ethylundecanoyl group, 12-methyltridecanoyl group, 12-methyl Tetradecanoyl group, 14-methylpentadecanoyl group, 16-methylheptadecanoyl group, 2,4,10,14-tetramethylpentanoyl group, 18-methylnonadecanoyl group, 3,7,11,15 Preferred examples include -tetra-methylhexadecanoyl group, 19-methyleicosanoyl group and the like.

The group derived from the trihydric alcohol represented by X or Y in the general formulas (1) and (3) is not particularly limited as long as the OH group is released from the trihydric alcohol. A group in which an OH group is eliminated from a trihydric alcohol selected from the group consisting of trimethylolpropane and trimethylolethane can be suitably exemplified.

In a preferred embodiment of the present invention, it is preferable to use a monomer represented by the general formula (5) as a hydrophobic monomer.

Examples of the hydrophobic monomer represented by the general formula (5) include compounds represented by the following formulas (12) to (14). Preferably, a compound represented by the following formula (12) in which a branched chain is added to the end of the acyl group is used.

Formula (12)

Formula (13)

Formula (14)

The hydrophobic monomer represented by the general formula (1) constituting the copolymer of the present invention can be synthesized, for example, by the following method.
a) Ketalize trihydric alcohol. As a specific synthesis method, for example, the method described in Production Example 1 of JP-A-2009-136749 can be exemplified.
b) Synthesis of a ketal (meth) acrylic ester by transesterification of the ketalized trihydric alcohol synthesized in a with a (meth) acrylic acid alkyl ester, and the resulting ketal (meth) acrylic ester Carboxylation reaction is performed to synthesize mono (meth) acrylic acid ester of trihydric alcohol. As a specific synthesis method, for example, the method described in Example 1 of JP-A-2004-18389 can be exemplified.
c) Hydrophobicity represented by the general formula (1) by reacting the mono (meth) acrylic acid ester of the trihydric alcohol obtained in b with a carboxylic acid having a predetermined branched structure or an anhydride or chloride thereof. Monomer is obtained.

In addition, since the ketalized trihydric alcohol also has a commercial item, it is also possible to obtain the ester of the trihydric alcohol of the present invention by using the commercial product and the above steps b) and c). Such commercial products include (S)-(+)-2,2-dimethyl-1,3-dioxalane-4-methanol, (R)-(+)-2,2-dimethyl-1,3- An example is dioxalane-4-methanol (both manufactured by Tokyo Chemical Industry Co., Ltd.). Furthermore, since there are commercially available products of mono (meth) acrylic acid esters of trihydric alcohols, it is also possible to obtain the esters of the trihydric alcohols of the present invention by the above step c) using such commercially available products. Examples of such commercially available products include “Blemmer GLM” (glycerin monomethacrylate manufactured by Nippon Oil & Fats Co., Ltd.).

In the copolymer of the present invention, the ratio of the structural unit (a) to the total structural units is preferably 1 to 40% by mass, more preferably 5 to 35% by mass.
By setting the proportion of the structural unit (a) within the above range, the elasticity of the copolymer of the present invention can be improved.

<2> Hydrophilic monomer The copolymer of the present invention contains one or more structural units derived from the hydrophilic monomer represented by the general formula (2) as essential structural units.

In the general formula (2), examples of the alkyl group represented by R4 include a methyl group, an ethyl group, a propyl group, an isopropyl group, and a cyclopropyl group. In the present invention, R4 is preferably a hydrogen atom or a methyl group.

Examples of the alkylene group represented by R5 include ethylene group, propylene group, isopropylene group, 2-hydroxypropylene group, 1-hydroxy-2-methylethylene group, 2-hydroxy-1-methylethylene group and the like. Of these, ethylene group or propylene group is preferable, and ethylene group is more preferable.

Among the groups represented by R6, examples of the aromatic group having 6 to 10 carbon atoms include a phenyl group, a benzyl group, a methylphenyl group, and an ethylphenyl group; an aliphatic carbon atom having 1 to 14 carbon atoms Preferred examples of the hydrogen group include a methyl group, an ethyl group, a butyl group, a tertiary butyl group, a hexyl group, a cyclohexyl group, an octyl group, a 2-ethylhexyl group, and a lauryl group; Preferred examples of the 12 acyl group include a formyl group, an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a valeryl group, and a lauroyl group. Of these, the group represented by R5 is preferably an aliphatic hydrocarbon group having 1 to 14 carbon atoms, and more preferably an alkyl group having 1 to 12 carbon atoms.

Furthermore, n in the general formula (2) is in the numerical range of 6 to 40.

Specific examples of the monomer represented by the general formula (2) in which R5 is a propylene group include polypropylene glycol (9) monoacrylate, polypropylene glycol (13) monoacrylate, and polypropylene glycol (9) monomethacrylate. And polypropylene glycol (13) monomethacrylate. The number in parentheses represents N. Many of these polymers are commercially available. Specific examples of such commercially available products include “Blemmer” AP-400, AP-550, AP-800, PP-500, PP-800 (all manufactured by NOF Corporation) and the like.

Specifically, among the monomers represented by the general formula (2), R5 is an ethylene group, specifically, 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 , Lauroyloxy polyethylene glycol (10) methacrylate, stearoxy polyethylene glycol (30) monomethac Rate, and the like.

In a preferred embodiment of the present invention, the monomer represented by the general formula (6) is used as the hydrophilic monomer.

In the general formula (6), l is preferably 6-30, more preferably 8-30.

The above-mentioned hydrophilic monomer can be obtained in high yield by esterification reaction of the corresponding polyethylene glycol, polyethylene glycol monoether, polyethylene glycol monoester with acrylic acid or methacrylic acid chloride or anhydride. Moreover, since there are already many commercial products, it is also possible to use such commercial products. Specific examples of such commercially available products include Blemmer, AE-400, PE-350, AME-400, PME-400, PME-1000, ALE-800, PSE-1300, etc. Etc.).

The structural unit derived from the hydrophilic monomer contained in the copolymer of the present invention may be only one type, but may contain two or more types of structural units in combination as long as the above conditions are satisfied.

In the copolymer of the present invention, the ratio of the structural unit (b) derived from the hydrophilic monomer to the total structural units is 30 to 95% by mass, preferably 40 to 90% by mass.
By setting the proportion of the structural unit (b) within the above range, the elasticity of the copolymer of the present invention can be improved.

<3> Other Arbitrary Units The copolymer of the present invention includes units derived from monomers usually used in a copolymer in addition to the above-mentioned structural unit 1 and structural unit 2 as long as the effects of the invention are not impaired. It can contain as arbitrary structural units. Examples of such optional structural units include acrylic acid amide, methacrylic acid amide, acrylic acid monoalkylamide, (meth) acrylic acid amide such as methacrylic acid monoalkylamide, methyl (meth) acrylate, ethyl (meth) acrylate, N-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-dodecyl methacrylate , (Meth) acrylic acid stearyl, (meth) acrylic acid isostearyl and other (meth) acrylic acid alkyl esters, (meth) acrylic acid cyclohexyl and other cyclic alkyl esters, 2-hydroxyethyl (meth) acrylate 2-hydroxypropyl (meth) acrylate, 4 -(Meth) acrylic acid hydroxyalkyl esters such as hydroxybutyl (meth) acrylate, (meth) acrylic acid aryl esters such as benzyl (meth) acrylate, methoxymethyl (meth) acrylate, methoxyethyl (meth) acrylate, etc. Examples thereof include structural units derived from monomers such as (meth) acrylic acid alkoxyalkyl esters, vinyl acetate, vinylpyrrolidone, styrene, α-methylstyrene, acrylonitrile and the like. Most of these monomers are commercially available.

<4> Copolymer of the Present Invention The copolymer of the present invention is a copolymer containing the structural unit (a) and the structural unit (b) in its skeleton. Further, the copolymer of the present invention is usually a random copolymer in which structural units are randomly bonded, but may be a block copolymer or a graft copolymer.

The copolymer of the present invention has a weight average molecular weight of 20,000 to 110,000. By setting the weight average molecular weight within the above range, the copolymer of the present invention becomes elastic.
The weight average molecular weight of the copolymer of the present invention is more preferably 20,000 to 80,000, more preferably 30,000 to 80,000, more preferably 40,000 to 70,000, still more preferably 50,000 to 70,000, still more preferably 57,000 to 66,000.
In addition, a weight average molecular weight here means the weight average molecular weight of polystyrene conversion measured by GPC.

The method for producing the copolymer of the present invention is not particularly limited. For example, the copolymer can be obtained by a method in which monomers for deriving each structural unit are mixed in a solvent and a polymerization reaction is carried out according to a method usually used in the polymerization of acrylic monomers.
Here, the weight average molecular weight of the copolymer can be adjusted by changing the reaction time and reaction temperature of the polymerization reaction. Specifically, the weight average molecular weight can be reduced by shortening the reaction time.

In addition, the copolymer of the present invention is preferably water-soluble because it is easy to handle. The copolymer here is defined as a copolymer having a transmittance of 90% or more of a 20% by mass aqueous solution of the copolymer at 25 ° C. In order to obtain such a polymer, among the above polymerization methods, a polymerization method in which the monomer mixture is radically polymerized in a mixed solvent of an aqueous solution and an aqueous solvent mixed with water at an arbitrary ratio at 25 ° C. is particularly preferable. . Moreover, since the amount of residual monomer after the polymerization reaction is small, a polymerization method using a buffer solution instead of water is more preferable. The aqueous solution having a buffering action used in this method is not particularly limited as long as it is a commonly used buffer solution. Specifically, potassium chloride-hydrochloric acid solution, potassium hydrogen phthalate-hydrochloric acid solution, dihydrogen phosphate Examples thereof include a potassium-disodium hydrogen phosphate solution, a potassium hydrogen citrate-citric acid solution, and a sodium carbonate-sodium hydrogen carbonate solution. Alternatively, an aqueous solution of salts, acids, or bases that forms a buffer solution with the ions of the initiator may be used to form a buffer solution when the initiator is added. Further, examples of the aqueous solvent used in this method which are miscible with water at an arbitrary ratio at 25 ° C. include alcohols having 1 to 3 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, and isopropyl alcohol. Examples thereof include ketones such as acetone and methyl ethyl ketone, diols such as ethylene glycol, polyethylene glycol, propylene glycol and 1,3 butylene glycol, ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether, and tetrahydrofuran. Among these aqueous solvents, alcohols having 1 to 3 carbon atoms such as methanol, ethanol, n-propanol, and isopropanol are particularly preferable because the polymerization reaction easily proceeds.

In the present invention, the mass ratio of the structural unit (a) to the structural unit (b) constituting the copolymer is preferably 5:95 to 50:50, more preferably 10:90 to 45:55, and still more preferably 20:80 to 40:60, more preferably 25:75 to 35:65.

The molar ratio of the structural unit (a) to the structural unit (b) constituting the copolymer is preferably 8:92 to 62:38, more preferably 15:85 to 57:43, and still more preferably 29:71. 52:48, more preferably 35:65 to 46:54.
By setting the mass ratio and the molar ratio of the structural unit (a) and the structural unit (b) in the copolymer within the above ranges, the feeling of elasticity can be further improved.

<5> External preparation for skin containing the copolymer of the present invention The external preparation for skin containing the copolymer of the present invention has a feeling of elasticity and hardly causes stickiness.
In the external preparation for skin, the content of the copolymer of the present invention is preferably 0.5 to 30% by mass, more preferably 1 to 25% by mass.

Favorable examples of the external preparation for skin of the present invention include external medicines such as ointments, cosmetics and the like. Furthermore, cosmetics include skin care such as creams, milky lotions, lotions, beauty essences, sunscreen cosmetics, make-ups such as under makeup, foundations, eye colors and mascara, skin cleansers such as facial cleansers, hair tonics, hair Examples thereof include hair cosmetics such as liquid and hair spray.

The external preparation for skin of the present invention can contain, as an optional component, components that are usually used for external preparations for skin as long as the effects of the invention are not impaired. As such optional components, specifically,
Macadamia nut oil, avocado oil, corn oil, olive oil, rapeseed oil, sesame oil, castor oil, safflower oil, cottonseed oil, jojoba oil, coconut oil, palm oil, liquid lanolin, hydrogenated coconut oil, hydrogenated oil, molasses, hydrogenated castor oil, Oils such as beeswax, candelilla wax, carnauba wax, ibotarou, lanolin, reduced lanolin, hard lanolin, jojoba wax, waxes, liquid paraffin, squalane, pristane, ozokerite, paraffin, ceresin, petrolatum, hydrocarbons such as microcrystalline wax, Higher fatty acids such as oleic acid, isostearic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, undecylenic acid, cetyl alcohol, stearyl alcohol, isostearyl alcohol, behenyl alcohol, Higher alcohols such as cutyldecanol, myristyl alcohol, cetostearyl alcohol, etc., cetyl isooctanoate, isopropyl myristate, hexyldecyl isostearate, diisopropyl adipate, di-2-ethylhexyl sebacate, cetyl lactate, diisostearyl malate, Di-2-ethylhexanoic acid ethylene glycol, dicapric acid neopentyl glycol, di-2-heptylundecanoic acid glycerin, tri-2-ethylhexanoic acid glycerin, tri-2-ethylhexanoic acid trimethylolpropane, triisostearic acid trimethylol Synthetic ester oils such as propane, tetra-2-ethylhexanoic acid pentane erythritol, dimethylpolysiloxane, methylphenylpolysiloxane, diphenylpolysiloxa Linear polysiloxanes such as, cyclic polysiloxanes such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexanesiloxane, amino-modified polysiloxane, polyether-modified polysiloxane, alkyl-modified polysiloxane, fluorine-modified polysiloxane, etc. Oils such as silicone oils such as modified polysiloxanes, fatty acid soaps (sodium laurate, sodium palmitate, etc.), anionic surfactants such as potassium lauryl sulfate, alkylethanol triethanolamine ether, stearyltrimethylammonium chloride, chloride Cationic surfactants such as benzalkonium and laurylamine oxide, imidazoline-based amphoteric surfactants (2-cocoyl-2-imidazolinium hydroxide-1-cal Boxyethyloxy disodium salt, etc.), betaine surfactants (alkyl betaine, amide betaine, sulfobetaine, etc.), amphoteric surfactants such as acylmethyltaurine, sorbitan fatty acid esters (sorbitan monostearate, sorbitan sesquioleate, etc.) ), Glycerin fatty acids (such as glyceryl monostearate), propylene glycol fatty acid esters (such as propylene glycol monostearate), hydrogenated castor oil derivatives, POE sorbitan fatty acid esters (POE sorbitan monooleate, polyoxyethylene monostearate) Sorbitan, etc.), POE sorbite fatty acid esters (POE-sorbitol monolaurate, etc.), POE glycerin fatty acid esters (POE-glycerol monoisostearate, etc.), POE fat Acid esters (polyethylene glycol monooleate, POE distearate, etc.), POE alkyl ethers (POE2-octyldodecyl ether, etc.), POE alkyl phenyl ethers (POE nonylphenyl ether, etc.), Pluronic types, POE / POP alkyl ethers (POE / POP2-decyltetradecyl ether, etc.), Tetronics, POE castor oil / hardened castor oil derivatives (POE castor oil, POE hardened castor oil, etc.), nonionic surfactants such as sucrose fatty acid ester, alkyl glucoside Polyethylene glycol, glycerin, 1,3-butylene glycol, erythritol, sorbitol, xylitol, maltitol, propylene glycol, dipropylene glycol, diglycerin, isoprene Moisturizing of polyhydric alcohols such as coal, 1,2-pentanediol, 2,4-hexylene glycol, 1,2-hexanediol, 1,2-octanediol, sodium pyrrolidonecarboxylate, lactic acid, sodium lactate, etc. Classification, guar gum, quince seed, carrageenan, galactan, gum arabic, pectin, mannan, starch, xanthan gum, curdlan, methylcellulose, hydroxyethylcellulose, carboxymethylcellulose, methylhydroxypropylcellulose, chondroitin sulfate, dermatan sulfate, glycogen, heparan sulfate, hyaluron Acid, sodium hyaluronate, tragacanth gum, keratan sulfate, chondroitin, mucoitin sulfate, hydroxyethyl guar gum, carboxymethyl guar gum, dextran , Keratosulfuric acid, locust bean gum, succinoglucan, caronic acid, chitin, chitosan, carboxymethylchitin, agar, polyvinyl alcohol, polyvinylpyrrolidone, carboxyvinyl polymer, sodium polyacrylate, polyethylene glycol, bentonite and other thickeners, Lower alcohols such as ethanol and isopropanol, hexyl diethylaminohydroxybenzoylbenzoate, t-butylmethoxybenzoylmethane, paraaminobenzoic acid UV absorbers, anthranilic acid UV absorbers, salicylic acid UV absorbers, cinnamic acid UV absorbers UV absorbers, vitamin A or its derivatives, vitamin B6 hydrochloride, vitamin B6 tripalmitate, vitamin B6 dioctanoate, vitamin B2 or its derivatives, vitamin B12, vitamin B15 such as vitamin B15 or derivatives thereof, α-tocopherol, β-tocopherol, γ-tocopherol, vitamin E such as vitamin E acetate, vitamin D, vitamin H, pantothenic acid, panthetin, pyrroloquinoline quinone, etc. Of these, vitamins can be preferably exemplified.

The external preparation for skin of the present invention can be prepared by treating the above essential components and optional components by a conventional method.

The feature of the emulsion composition of the present invention that solves the second problem is that the water-soluble copolymer has a structural unit (c) derived from a hydrophobic monomer and a structural unit (d) derived from a hydrophilic monomer. It is to include. Hereinafter, in the item <1>, a hydrophobic monomer, a hydrophilic monomer, and a water-soluble copolymer that is a copolymer thereof will be described.

<1> Water-soluble copolymer [1] Hydrophobic monomer In the present invention, a structural unit derived from the hydrophobic monomer represented by the general formula (1), (7) or (8) (hereinafter simply referred to as “ A water-soluble copolymer containing one or more structural units (sometimes referred to as “structural unit (7)”) as essential structural units is used.
In the present invention, the “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 (1), (7) or (8) will be described.

(1-1) Hydrophobic monomer represented by the general formula (7) In the general formula (7), R14 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R15 represents a ring having 13 to 30 carbon atoms. A branched hydrocarbon group not containing a structure or a hydrocarbon group having 6 to 12 carbon atoms having two or more branches not containing a ring structure is represented.
Here, examples of the alkyl group represented by R14 include a methyl group, an ethyl group, a propyl group, an isopropyl group, and a cyclopropyl group. In the present invention, R14 is preferably a hydrogen atom or a methyl group.

Examples of the branched hydrocarbon group not containing a ring structure having 13 to 30 carbon atoms represented by R15 include 1-methyldodecanyl group, 11-methyldodecanyl group, 3-ethylundecanyl group, 3- Ethyl-4,5,6-trimethyloctyl, 1-methyltridecanyl, 1-hexyloctyl, 2-butyldecanyl, 2-hexyloctyl, 4-ethyl-1-isobutyloctyl, 1-methyl Pentadecanyl group, 2-hexyldecanyl group, 2-octyldecanyl group, 2-hexyldecanyl group, 16-methylheptadecanyl group, 9-methylheptadecanyl group, 7-methyl-2- (3 -Methylhexyl) decanyl group, 3,7,11,15-tetra-methylhexadecanyl group, 2-octyldodecanyl group, 2-decyltetradecanyl group, 2-dodecylhexyl It can be exemplified decanyl group.

In addition, examples of the hydrocarbon group having 6 to 12 carbon atoms having two or more branches and not including a ring structure represented by R15 include 2,2-dimethylbutyl group, 2,3-dimethylbutyl group, 3, 3-dimethylbutyl group, 1,3-dimethylbutyl group, 1,2,2-trimethylpropyl group, 1,1-dimethylpentanyl group, 1-isopropylbutyl group, 1-isopropyl-2-methylpropyl group, 1 , 1-diethylpropyl group, 1-ethyl-1-isopropylpropyl group, 2-ethyl-4-methylpentyl group, 1-propyl-2,2-dimethylpropyl group, 1,1,2-trimethyl-pentyl group, 1-isopropyl-3-methylbutyl group, 1,2-dimethyl-1-ethylbutyl group, 1,3-dimethyl-1-ethylbutyl group, 1-ethyl-1-isopropyl-propyl group 1,1-dimethylhexyl group, 1-methyl-1-ethylpentyl group, 1-methyl-1-propylbutyl group, 1,4-dimethylhexyl group, 1-ethyl-3-methylpentyl group, 1,5 -Dimethylhexyl group, 1-ethyl-6-methylheptyl group, 1,1,3,3-tetramethylbutyl group, 1,2-dimethyl-1-isopropylpropyl group, 3-methyl-1- (2,2 -Dimethylethyl) butyl group, 1-isopropylhexyl group, 3.5.5-trimethylhexyl group, 2-isopropyl-5-methylhexyl group, 1,5-dimethyl-1-ethylhexyl group, 3,7-dimethyloctyl Group, 2,4,5-trimethylheptyl group, 2,4,6-trimethylheptyl group, 3,5-dimethyl-1- (2,2-dimethylethyl) hexyl group, etc. It is possible.

(1-2) Hydrophobic monomer represented by the general formula (1) or (8) In the general formulas (1) and (8), R1 and R16 each represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. , R2, R3, R17, R18, and R19 may be the same or different and each represents a branched acyl group having 6 to 22 carbon atoms that does not contain a ring structure. X represents a group in which an OH group is eliminated from a trivalent alcohol.

Here, examples of the alkyl group represented by R1 and R16 include a methyl group, an ethyl group, a propyl group, an isopropyl group, and a cyclopropyl group. In the present invention, R1 is preferably a hydrogen atom or a methyl group.

Examples of the branched acyl group having 6 to 22 carbon atoms that does not include the ring structure represented by R2, R3, R17, R18, and R19 include 2-methylpentanoyl group, 3-methylpentanoyl group, 4 -Methylpentanoyl group, 2-ethylbutanoyl group, 2-ethylbutanoyl group, 2,2-dimethylbutanoyl group, 3,3-dimethylbutanoyl group, 2-methylhexanoyl group, 4-methylhexanoyl group Group, 5-methylhexanoyl group, 2,2-dimethylpentanoyl group, 4,4-dimethylpentanoyl group, 2-methylheptanoyl group, 2-ethylhexyl group, 2-propylpentanoyl group, 2,2- Dimethylhexanoyl group, 2,2,3-trimethylpentanoyl group, 2-methyloctanoyl group, 3,3,5-trimethylhexanoyl group, 2-methylno Noyl group, 4-methylnonanoyl group, 8-methylnonanoyl group, 4-ethyloctanoyl group, 2-ethyloctanoyl group, 2-butylhexanoyl group, 2-tert-butylhexanoyl group, 2,2-diethylhexanoyl group 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, 2,2 dimethyldecanoyl 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, 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-hexyldodecane Noyl group, 2,4,10,14-tetramethylpentanoyl group, 18-methylnonadecanoyl group, 3,7,11,15-tetra-methylhexadecanoyl group, 19-methyleicosanoyl group, etc. It can be illustrated.

In a preferred embodiment of the present invention, in the general formulas (1) and (8), R2, R3, R17, R18, and R19 may be the same or different and do not include a ring structure and have a branch. An acyl group having 10 to 22 carbon atoms, or an acyl group having 6 to 9 carbon atoms having two or more branches that does not contain a ring structure.

Such a branched acyl group having 10 to 22 carbon atoms which does not contain a ring structure and is represented by R2, R3, R17, R18 and R19 in a preferred embodiment includes a 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-methylun Decanoyl group, 2,2 dimethyldecanoyl group, 2-ethyldecanoyl group, 2-butyloctanoyl group, diethyloctanoy 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, 2-butyl-2-ethyloctanoyl group, 12-methyltetradecanoyl group, 14-methyl Pentadecanoyl group, 2-butyldodecanoyl group, 2-hexyldecanoyl group, 16-methylheptadecanoyl group, 2,2-dimethylhexanoyl group, 2-butylhexadecanoyl group, 2-hexyldecanoyl group 2,4,10,14-tetramethylpentanoyl group, 18-methylnonadecanoyl group, 3,7,11,15-tetra-methyl Examples thereof include a ruhexadecanoyl group and a 19-methyleicosanoyl group.

Further, in the preferred embodiment, the acyl group having 6 to 9 carbon atoms having 2 or more branches and containing no ring structure represented by R2, R3, R17, R18, R19 is 2,2-dimethyl. Butanoyl group, 3,3-dimethylbutanoyl group, 2,2-dimethylpentanoyl group, 4,4-dimethylpentanoyl group, 2,2-dimethylhexanoyl group, 2,2,3-

trimethylpentanoyl group

3,5,5-trimethylhexanoyl group and the like.

The group derived from the trihydric alcohol represented by X in the general formula (1) is not particularly limited as long as the OH group is eliminated from the trihydric alcohol, but glycerin, trimethylolpropane, trimethylolethane. A group in which an OH group is eliminated from a trihydric alcohol selected from the group consisting of

The group derived from the tetrahydric alcohol represented by Y in the general formula (8) is not particularly limited as long as the OH group is released from the tetrahydric alcohol, but diglycerin, pentaerythritol, erythritol. A group in which an OH group is eliminated from a tetrahydric alcohol selected from the group consisting of D-threitol and L-threitol can be suitably exemplified.

In the present invention, it is particularly preferable to use a water-soluble copolymer containing the structural unit (1).
In a more preferred embodiment of the present invention, the hydrophobic monomer represented by the general formula (1) is a hydrophobic monomer represented by the following general formula (15).

General formula (15)

(15)
(In the general formula (15), R24 and R25 may be the same or different and each represents a branched, acyl group having 16 to 22 carbon atoms that does not contain a ring structure. Z represents an OH group from a trivalent alcohol. Represents a leaving group.)

The carbon number of the acyl group of R24 and R25 in the general formula (15) is 12 to 22, more preferably 14 to 20, and still more preferably 16 to 20.
The carbon number of the main chain of the acyl group of R24 and R25 in the general formula (15) is preferably 9 to 21, more preferably 12 to 20, and still more preferably 16 to 18.
Further, the number of branches in the acyl group of R24 and R25 in the general formula (15) is preferably 1 to 3, more preferably 1 or 2, and still more preferably 1.
Furthermore, in the acyl groups of R24 and R25 in the general formula (15), the position number of carbon in the main chain to which the branched chain is bonded is preferably as large as possible. Specifically, the branched chain is bonded to the carbon at the end of the main chain, preferably from the 1st to 3rd carbon, more preferably the 1st or 2nd carbon, and even more preferably the 1st carbon. It is preferable.

Specific examples of R24 and R25 include 10-methylundecanoyl group, 10-methyldodecanoyl group, 11-methyldodecanoyl group, 10-ethylundecanoyl group, 12-methyltridecanoyl group, 12-methyl Tetradecanoyl group, 14-methylpentadecanoyl group, 16-methylheptadecanoyl group, 2,4,10,14-tetramethylpentanoyl group, 18-methylnonadecanoyl group, 3,7,11,15 Preferred examples include -tetra-methylhexadecanoyl group, 19-methyleicosanoyl group and the like.

The group derived from the trihydric alcohol represented by Z in the general formula (15) is not particularly limited as long as the OH group is released from the trihydric alcohol, but glycerin, trimethylolpropane, trimethylolethane. A group in which an OH group is eliminated from a trihydric alcohol selected from the group consisting of

[2] Hydrophilic monomer As the hydrophilic monomer in the present invention, a polymerizable carboxylic acid and the compounds represented by the general formula (2), the general formulas (9), (10) and (11) are used. Can do.

(2-1) Polymerizable carboxylic acid In the present invention, the polymerizable carboxylic acid or a salt thereof specifically includes acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid and its sodium salt, potassium salt, Examples thereof include ammonium salts and amine salts. Among these, acrylic acid, methacrylic acid and salts thereof are particularly preferable because of high polymerizability. When a structural unit derived from a polymerizable carboxylic acid salt is introduced into the water-soluble copolymer of the present invention, the polymerizable carboxylic acid may be converted into a salt in advance, and a polymerization reaction may be performed. A structural unit derived from a carboxylic acid may be derived into a water-soluble copolymer and then neutralized with a base to form a salt.

(2-2) Hydrophilic monomer represented by general formula (2) In the general formula (2), R4 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R5 may have a hydroxyl group. Represents a good alkylene group having 2 to 4 carbon atoms, and R6 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. To express. n represents an integer of 6 to 40.

Furthermore, n in the general formula (2) is in the numerical range of 6 to 40.

(2-3) Hydrophilic monomer represented by general formula (9) As the hydrophilic monomer in the present invention, a hydrophilic monomer represented by general formula (9) may be used.

Specific examples of the hydrophilic monomer represented by the general formula (9) include 2-acryloyloxyethyl phosphorylcholine (APC) and 2-methacryloyloxyethyl phosphorylcholine (MPC). These monomers can be synthesized by the following method described in Polymer Journal, Vol 22, No. 5, for example.
<Synthesis method>
2-bromoethyl phosphoryl dichloride is reacted with 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate to give 2-methacryloyloxyethyl-2′-bromoethyl phosphate or 2-acryloyloxyethyl-2′-bromoethyl phosphate Are obtained, and these compounds are reacted with triethylamine in methanol.

(2-4) Hydrophilic monomer represented by general formula (10) As the hydrophilic monomer in the present invention, a hydrophilic monomer represented by general formula (10) may be used.

In the hydrophilic monomer represented by the general formula (10), as 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—, specifically, glucose, mannose, Examples include one or more selected from the group consisting of monosaccharides such as galactose, arabinose, xylose and ribose, disaccharides such as maltose, lactose and cellobiose, trisaccharides such as maltotriose, and oligosaccharides such as malto-oligosaccharide However, among these, one or more selected from the group consisting of glucose, galactose, arabinose, xylose, ribose, maltose, and lactose cellobiose is preferable, and glucose is particularly preferable. The monomer represented by the general formula (10) is preferably glucosyloxyethyl methacrylate (hereinafter abbreviated as GEMA) or glucosyloxyethyl acrylate (hereinafter abbreviated as GEA).

(2-5) Hydrophilic monomer represented by general formula (11) As the hydrophilic monomer in the present invention, a hydrophilic monomer represented by general formula (11) may be used.

In the monomer of the general formula (11), the amino acid of the amino acid residue represented by R23 is not particularly limited as long as it is a commonly known amino acid. Specifically, glycine, alanine, glutamine, lysine, arginine Etc. are exemplified. Among these, the lysine residue is particularly preferable because the obtained water-soluble copolymer is excellent in the effect of restoring the skin barrier.

In addition, the polyamine in the polyamine residue represented by R23 means an amine having two or more amino groups that may be substituted with an alkyl group in the same molecule, and specifically includes diamine, triamine, tetraamine. Or the amine by which the hydrogen atom of these amino groups is substituted by the alkyl group is illustrated. Of these, diamines are preferred because the feeling of use of the resulting external preparation for skin containing the water-soluble copolymer is particularly excellent. Particularly preferred examples include ethylenediamine, 1 from the availability of raw materials for synthesis. , 4-diamino-n-butane, 1,6-diamino-n-hexane and the like.

Furthermore, the amino alcohol in the amino alcohol residue represented by R23 means a compound having an amino group which may be substituted with an alkyl group in the same molecule and an alcoholic hydroxyl group. The amino alcohol is not particularly limited as long as it is generally known, but specific examples include ethanolamine and triethylaminoethanol.

Although it does not specifically limit as a salt of the monomer represented by General formula (11), Specifically, the sodium salt, potassium salt, ammonium salt, amine salt, etc. which neutralized the acid part with the base, Examples thereof include hydrochlorides, sulfates, nitrates, phosphates, citrates, oxalates, carbonates, etc., in which the amino group is neutralized with an acid. When the structural unit derived from the salt of the monomer represented by the general formula (11) is introduced into the water-soluble copolymer of the present invention, the monomer represented by the general formula (11) is converted into a salt in advance to carry out the polymerization reaction. Alternatively, the structural unit derived from the monomer represented by the general formula (11) may be derived into a water-soluble copolymer by a polymerization reaction, and then neutralized to form a salt.

Specific examples of the monomer represented by the general formula (11) and salts thereof include compounds 1 to 11 having the following structures and salts thereof.

Compound 1

Compound 2

Compound 3

Compound 4

Compound 5

Compound 6

Compound 7

Compound 8

Compound 9

Compound 10

Compound 11

The hydrophilic monomer represented by the general formula (11) is, for example, an esterification reaction using (meth) acrylic acid or (meth) acrylic acid chloride as shown in the following reaction formulas (1) and (2), amide It can be synthesized by a chemical reaction.
Reaction formula (1)

Reaction formula (2)

(In the reaction formula, R22 represents a hydrogen atom or a methyl group, R23 represents an amino acid residue, a polyamine residue or an aminoalcohol residue. Q represents an oxygen atom or a group represented by NH.)

As described above, as the hydrophilic polymer in the present invention, the general formula (2), the general formula (9), the general formula (10), and the general formula (11) can be used.
In a preferred embodiment of the present invention, the water-soluble copolymer contains the structural unit (2) derived from the general formula (2).

[3] Water-soluble copolymer In the present invention, a water-soluble copolymer having the structural unit (1) and the structural unit (2) can be preferably used. More preferably, a water-soluble copolymer having the structural unit (15) and the structural unit (2) is used.
Of such water-soluble copolymers, a (methoxy PEG-23 methacrylate / glyceryl methacrylate) is particularly preferably used.
By containing such a water-soluble copolymer, the emulsion composition is low in irritation, less sticky, and excellent in emulsion stability.

(Methoxymethacrylic acid PEG-23 / glyceryl methacrylate) is a structural unit (c) in which R24 and R25 are 16-methylheptadecanoyl among the hydrophobic monomers represented by the general formula (15). It mainly contains a structural unit (c) derived from a hydrophobic monomer as a group.
Further, among the hydrophilic monomers represented by the general formula (2), the structural unit (d) is derived from a hydrophilic monomer in which R4 is a methyl group, R5 is an ethylene group, R6 is a methyl group, and n is 23. The structural unit (d) is mainly included.

Generally, a highly hydrophobic surfactant is suitable for forming a water-in-oil emulsion composition, and on the contrary, a highly hydrophilic surfactant is suitable for forming an oil-in-water emulsion composition. Similarly, the water-soluble copolymer in the present invention is suitable for forming a water-in-oil type emulsion composition when the proportion of the structural unit (c) that is hydrophobic is high, and is hydrophilic. When the proportion of a certain structural unit (d) is high, it is suitable for forming an oil-in-water emulsion composition.
Thus, the emulsification form of the emulsion composition to be formed can be adjusted by appropriately adjusting the proportion and ratio of the structural unit (c) and the structural unit (d).

In the present invention, the proportion of the structural unit (c) in all the structural units in the water-soluble copolymer is preferably 1 to 50% by mass, more preferably 20 to 50% by mass, and 30 to 40% by mass.
By setting the proportion of the structural unit (c) in the water-soluble copolymer within the above range, it is possible to provide an oil-in-water emulsion composition with a reduced stickiness.

In the present invention, the proportion of the structural unit (d) in all the structural units in the water-soluble copolymer is preferably 50 to 99% by mass, more preferably 50 to 80% by mass, and 60 to 70% by mass.
By setting the proportion of the structural unit (d) in the water-soluble copolymer within the above range, it is possible to provide an oil-in-water emulsion composition with a more reduced stickiness.

In the present invention, the mass ratio of the structural unit (c) and the structural unit (d) constituting the water-soluble copolymer is preferably 10:90 to 50:50, more preferably 20:80 to 50:50, Preferably, it is 30:70 to 40:60.

The molar ratio of the structural unit (c) to the structural unit (d) constituting the water-soluble copolymer is preferably 15:85 to 62:38, more preferably 29:71 to 62:38, and still more preferably 41. : 59-52: 48.
By making the mass ratio and the molar ratio of the structural unit (c) and the structural unit (d) in the water-soluble copolymer within the above ranges, the water-soluble water solution is excellent in emulsifying power and suitable for forming an oil-in-water emulsion composition. Copolymer.

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, still more preferably 50,000 to 70,000, still more preferably. 57000-66000.
In addition, an average molecular weight means here the weight average molecular weight of polystyrene conversion measured by GPC.

<2> Emulsified Composition The emulsified composition of the present invention is characterized by substantially not containing an emulsifier other than the above-mentioned water-soluble copolymer.
Here, “substantially free of an emulsifier other than the above-mentioned water-soluble copolymer” means that the content of the emulsifier other than the above-mentioned water-soluble copolymer is 0.3% by mass or less, preferably 0.1% by mass or less. More preferably, it means 0.01% by mass or less, more preferably 0.001% by mass or less. Moreover, it is especially preferable not to contain emulsifiers other than the above-mentioned water-soluble copolymer.

The content of the above water-soluble copolymer in the emulsion composition is preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass.
By making content of the above-mentioned water-soluble copolymer into the said range, the emulsion stability of an emulsion composition can be improved more.

The contents of the aqueous phase and the oil phase in the emulsion composition of the present invention can be appropriately adjusted by changing the ratio of the structural unit (c) and the structural unit (d) in the water-soluble copolymer.
Hereinafter, the content of the oil phase and the water phase when a water-soluble copolymer containing the structural unit (c) and the structural unit (d) is used in a ratio suitable for forming the above-described oil-in-water emulsion composition, etc. Will be described.
In the present specification, the oil phase and the oil phase component, and the water phase and the water phase component are described as not including the water-soluble copolymer in the present invention.

The content of the oil phase component in the emulsion composition of the present invention is preferably 0.01 to 80% by mass, more preferably 0.1 to 70% by mass.
By making content of an oil phase component into the said range, the emulsification stability of an emulsion composition can be improved.
In addition, an oil phase component is an oil agent and a lipophilic component, and means the component contained in an oil phase in an emulsion composition.

In the emulsified composition of the present invention, the mass ratio of the water-soluble copolymer and the oil phase component is preferably 1: 100 to 1: 0.2, more preferably 1:70 to 1: 0.3.
By setting the mass ratio of the water-soluble copolymer and the oil phase component in the above range, the emulsion stability of the emulsion composition can be improved.

In the emulsified composition of the present invention, the mass ratio of the oil phase to the aqueous phase is preferably 0.1: 99.9 to 80:20, more preferably 1:99 to 65:35.
By setting the mass ratio of the oil phase to the water phase in the above range, a stable oil-in-water emulsion composition can be formed.

The components contained in the oil phase and the aqueous phase are not particularly limited.
Examples of the oil agent constituting the oil phase include liquid oils and fats, solid oils and fats, waxes, hydrocarbon oils, higher fatty acids, higher alcohols, synthetic ester oils, silicone oils, and the like.

Examples of liquid oils 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, southern castor oil, castor oil, linseed oil , Safflower oil, cottonseed oil, eno oil, meadow foam oil, soybean oil, peanut oil, tea seed oil, kaya oil, rice bran oil, cinnagari oil, Japanese kiri oil, jojoba oil, germ oil, triglycerin, glycerin trioctanoate, Examples include glycerin triisopalmitate.

Solid fats and oils include cocoa butter, coconut oil, horse fat, hydrogenated coconut oil, palm oil, beef tallow, sheep fat, hardened beef tallow, palm kernel oil, pork fat, beef bone fat, owl kernel oil, hydrogenated oil, and cow leg fat. , Mole, hardened castor oil, and the like.

The waxes include beeswax, candelilla wax, cotton wax, carnauba wax, bayberry wax, ibota wax, whale wax, montan wax, nuka wax, lanolin, kapok wax, lanolin acetate, liquid lanolin, sugar cane wax, lanolin fatty acid isopropyl, lauryl hexyl, reduced lanolin, jojojo Examples thereof include a wax, hard lanolin, shellac wax, POE lanolin alcohol ether, POE lanolin alcohol acetate, POE cholesterol ether, lanolin fatty acid polyethylene glycol, POE hydrogenated lanolin alcohol ether, and the like.

Examples of hydrocarbon oils include liquid paraffin, ozokerite, pristane, paraffin, ceresin, squalene, petrolatum, and microcrystalline wax.

Examples of higher fatty acids include lauric acid, myristic acid, palmitic acid, stearic acid, behen (behenine) acid, 12-hydroxystearic acid, undecylenic acid, and toric acid.

Examples of higher alcohols include cetyl alcohol, stearyl alcohol, behenyl alcohol, batyl alcohol, myristyl alcohol, cetostearyl alcohol, and the like.

Synthetic ester oils include isopropyl myristate, cetyl octanoate, octyldodecyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, myristyl myristate, decyl oleate, hexyl decyl dimethyloctanoate, cetyl lactate, myristyl lactate Lanolin acetate, isocetyl stearate, isocetyl isostearate, sucrose stearate, sucrose oleate, cholesteryl 12-hydroxystearylate, ethylene glycol di-2-ethylhexylate, dipentaerythritol fatty acid ester, N-alkyl glycol monoisostearate, Neopentyl glycol dicaprate, diisostearyl malate, glycerin di-2-heptylundecanoate, tri-2-ethyl Trimethylolpropane hexylate, trimethylolpropane triisostearate, pentane erythritol tetra-2-ethylhexylate, glycerin tri-2-ethylhexylate, trimethylolpropane triisostearate, cetyl 2-ethylhexanoate, 2-ethylhexyl palmitate Glyceryl trimyristate, glyceride tri-2-heptylundecanoate, castor oil fatty acid methyl ester, oleic acid oil, cetostearyl alcohol, acetoglyceride, 2-heptylundecyl palmitate, cetyl palmitate, diisobutyl adipate, N- Lauroyl-L-glutamic acid-2-octyldodecyl ester, di-2-heptylundecyl adipate, ethyl laurate, di-2-ethyl sebacate Hexyl myristate 2-hexyl decyl palmitate, 2-hexyldecyl, 2-hexyldecyl adipate, sebacic acid diisopropyl, 2-ethylhexyl succinate, ethyl acetate, butyl acetate, amyl acetate, and triethyl citrate.

Examples of silicone oils include chain polysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, and methylhydrogenpolysiloxane, and cyclic polysiloxanes such as decamethylpolysiloxane, dodecamethylpolysiloxane, and tetramethyltetrahydrogenpolysiloxane. Is mentioned.

One or more oil agents can be used.

In the emulsified composition of the present invention, optional additive components that are usually blended in cosmetics may be blended within a range that does not impair the effects of the present invention. Examples of such additive components include humectants such as polyethylene glycol, glycerin, 1,3-butylene glycol, erythritol, sorbitol, xylitol, and maltitol; lower alcohols such as ethanol; butylhydroxytoluene, tocopherol, and phytin. Antioxidants; antibacterial agents such as benzoic acid, salicylic acid, sorbic acid, paraoxybenzoic acid alkyl ester, hexachlorophene; paraaminobenzoic acid (hereinafter abbreviated as “PABA”), PABA monoglycerin ester, N, N-dipropoxy PABA ethyl ester N, N-diethoxy PABA ethyl ester, N, N-dimethyl PABA methyl ester, N, N-dimethyl PABA ethyl ester, N, N-dimethyl PABA butyl ester, N, N-dimethyl P Benzoic acid UV absorbers such as BA2-ethylhexyl ester; Anthranilic acid UV absorbers such as homomenthyl-N-acetylanthranilate; Amyl salicylate, menthyl salicylate, homomenthyl salicylate, octyl salicylate, phenyl salicylate, benzyl salicylate -Salicylic acid ultraviolet absorbers such as isopropanol phenyl salicylate; octyl cinnamate, ethyl-4-isopropyl cinnamate, methyl-2,5-diisopropyl cinnamate, ethyl-2,4-diisopropyl cinnamate, methyl-2,4- Diisopropyl cinnamate, propyl-p-methoxycinnamate, isopropyl-p-methoxycinnamate, isoamyl-p-methoxycinnamate, octyl-p-methoxy Cinnamate (2-ethylhexyl-p-methoxycinnamate), 2-ethoxyethyl-p-methoxycinnamate, cyclohexyl-p-methoxycinnamate, ethyl-α-cyano-β-phenylcinnamate, 2-ethylhexyl-α- Cinnamic acid UV absorbers such as cyano-β-phenylcinnamate and glyceryl mono-2-ethylhexanoyl-diparamethoxycinnamate; [3-bis (trimethylsiloxy) methylsilyl-1-methylpropyl] -3, 4,5-trimethoxycinnamate, [3-bis (trimethylsiloxy) methylsilyl-3-methylpropyl] -3,4,5-trimethoxycinnamate, [3-bis (trimethylsiloxy) methylsilylpropyl] -3 , 4,5-trimethoxycinnamate, [3-bis (to Methylsiloxy) methylsilylbutyl] -3,4,5-trimethoxycinnamate, [3-tris (trimethylsiloxy) silylbutyl] -3,4,5-trimethoxycinnamate, [3-tris (trimethylsiloxy) silylbutyl 3,4,5-trimethoxycinnamate, silicone-based cinnamic acid UV absorbers such as [3-tris (trimethylsiloxy) silyl-1-methylpropyl] -3,4-dimethoxycinnamate; 2,4 -Dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2'4,4'-tetrahydroxybenzophenone, 2-hydroxy-4- Methoxybenzophenone, 2-hydroxy-4-methoxy-4'-me Rubenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonate, 4-phenylbenzophenone, 2-ethylhexyl-4'-phenyl-benzophenone-2-carboxylate, 2-hydroxy-4-n-octoxybenzophenone Benzophenone ultraviolet absorbers such as 4-hydroxy-3-carboxybenzophenone; 3- (4′-methylbenzylidene) -d, l-camphor, 3-benzylidene-d, l-camphor, urocanic acid ethyl ester, 2- Phenyl-5-methylbenzoxazole, 2,2′-hydroxy-5-methylphenylbenzotriazole, 2- (2′-hydroxy-5′-t-octylphenyl) benzotriazole, 2- (2′-hydroxy- 5'-methylphenyl) benzotriazol , Dibenzalazine, dianisoylmethane, 4-methoxy-4′-tert-butyldibenzoylmethane, 5- (3,3′dimethyl-2-norbornylidene) -3-pentan-2-one, and other ultraviolet absorbers; acyl Organic acids such as sarcosine acid (eg, lauroyl sarcosine sodium), glutathione, citric acid, malic acid, tartaric acid, lactic acid; vitamin A and its derivatives, vitamin B6 hydrochloride, vitamin B6 tripalmitate, vitamin B6 dioctanoate, vitamin B2 and its Derivatives, vitamin B such as vitamin B12, vitamin B15 and derivatives thereof, α-tocopherol, β-tocopherol, γ-tocopherol, vitamin E such as vitamin E acetate, vitamin D, vitamin H, pantothenic acid, panthetin, nicotine Acid amide, di Vitamins such as benzyltinate; γ-oryzanol, allantoin, glycyrrhizic acid (salt), glycyrrhetinic acid and derivatives thereof, tranexamic acid and derivatives thereof [tranexamic acid derivatives include dimers of tranexamic acid (for example, trans-hydrochloric acid trans- 4- (trans-aminomethylcyclohexanecarbonyl) aminomethylcyclohexanecarboxylic acid, etc.), esters of tranexamic acid and hydroquinone (eg, trans-4-aminomethylcyclohexanecarboxylic acid 4′-hydroxyphenyl ester, etc.), tranexamic acid And esters of gentisic acid (for example, 2- (trans-4-aminomethylcyclohexylcarbonyloxy) -5-hydroxybenzoic acid and its salts), amides of tranexamic acid (for example, (S-4-aminomethylcyclohexanecarboxylic acid methylamide and its salt, trans-4- (P-methoxyvinzoyl) aminomethylcyclohexanecarboxylic acid and its salt, trans-4-guanidinomethylcyclohexanecarboxylic acid and its salt, etc.) ), Saponins such as hinokitiol, bisabolol, eucalptone, thymol, inositol, psychosaponin, carrot saponin, hechimasaponin, muclodisaponin, pantothenyl ethyl ether, ethinyl estradiol, tranexamic acid, arbutin, cephalanthin, placenta extract, etc. Drugs: Barefoot, Clara, corn, orange, sage, yarrow, mallow, thyme, thyme, spruce, spruce, birch, horsetail, loofah, maronier, saxifrage Extracts of plants such as arnica, lily, mugwort, peonies, aloe, gardenia, sawara; pigments; porous and / or water-absorbing powders (eg starches derived from corn, potatoes, silicic acid, talc) , Powders of kaolin, aluminum magnesium silicate, calcium alginate, etc.); neutralizers; preservatives; fragrances; pigments and the like.

The emulsion composition of the present invention can be produced by preparing an aqueous phase component and an oil phase component each containing the above-mentioned water-soluble copolymer and stirring and mixing them in a conventional manner.

The emulsified composition of the present invention has low irritation and less stickiness, so it can be used as cosmetics such as emulsions, creams, serums, sunscreens, liquid foundations, skin external preparations, quasi drugs and pharmaceuticals. Is preferred.

<3> Emulsifier The present invention also relates to an emulsifier comprising the above-mentioned water-soluble copolymer. The description regarding the water-soluble copolymer and the emulsion composition described above can be applied to the emulsifier of the present invention.

<4> Manufacturing method of emulsion composition This invention relates also to the method of manufacturing an emulsion composition using the emulsifier of this invention mentioned above. The method of the present invention is characterized in that no emulsifier other than the emulsifier of the present invention is used. The description regarding the water-soluble copolymer and the emulsion composition described above can be applied to the production method of the present invention.

The features of the skin cleanser of the present invention that solves the third and fourth problems are water-soluble having a structural unit (e) derived from a hydrophobic monomer and a structural unit (f) derived from a hydrophilic monomer. Including a copolymer. Hereinafter, in the item <1>, a hydrophobic monomer, a hydrophilic monomer, and a water-soluble copolymer that is a copolymer thereof will be described.

trimethylpentanoyl group

3,5,5-trimethylhexanoyl group and the like.

In the present invention, it is particularly preferable to use a water-soluble copolymer containing the structural unit (1).
In a more preferred embodiment of the present invention, the hydrophobic monomer represented by the general formula (1) is a hydrophobic monomer represented by the general formula (15).

[2] Hydrophilic monomer As the hydrophilic monomer in the present invention, polymerizable carboxylic acid and compounds represented by the general formulas (2), (9), (10) and (11) can be used.

Furthermore, n in the general formula (2) is in the numerical range of 6 to 40.

In the monomer of the general formula (11), the amino acid of the amino acid residue represented by R23 is not particularly limited as long as it is a commonly known amino acid. Specifically, glycine, alanine, glutamine, lysine, Arginine etc. are illustrated. Among these, the lysine residue is particularly preferable because the obtained water-soluble copolymer is excellent in the effect of restoring the skin barrier.

Specific examples of the monomer represented by the general formula (11) and salts thereof include the above-mentioned compounds 1 to 11 and salts thereof.

The hydrophilic monomer represented by the general formula (11) is, for example, an esterification reaction using (meth) acrylic acid or (meth) acrylic acid chloride, amide as shown in the reaction formulas (1) and (2). It can be synthesized by a chemical reaction.

[3] Water-soluble copolymer In the present invention, a water-soluble copolymer having the structural unit (1) and the structural unit (2) can be preferably used. More preferably, a water-soluble copolymer having the structural unit (15) and the structural unit (2) is used.
Of such water-soluble copolymers, a (methoxy PEG-23 methacrylate / glyceryl methacrylate) is particularly preferably used.
By containing such a water-soluble copolymer, it is possible to provide a skin cleanser with less tension after use.

(Methoxymethacrylic acid PEG-23 / glyceryl methacrylate) is a structural unit (e) in which, among the hydrophobic monomers represented by the general formula (15), R24 and R25 are 16-methylheptadecanoyl. It mainly contains a structural unit (e) derived from a hydrophobic monomer as a group.
In addition, among the hydrophilic monomers represented by the general formula (2), the structural unit (f) is derived from a hydrophilic monomer in which R4 is a methyl group, R5 is an ethylene group, R6 is a methyl group, and n is 23. The structural unit (f) is mainly included.

In the present invention, the proportion of the structural unit (e) in all the structural units in the water-soluble copolymer is preferably 1 to 60% by mass, more preferably 10 to 50% by mass, and 20 to 40% by mass.
By setting the proportion of the structural unit (e) in the water-soluble copolymer within the above range, it is possible to provide a skin cleanser with a reduced feeling of tension after use.

In the present invention, the proportion of the structural unit (f) in all the structural units in the water-soluble copolymer is preferably 40 to 99% by mass, more preferably 50 to 90% by mass, and 60 to 80% by mass.
By setting the proportion of the structural unit (f) in the water-soluble copolymer within the above range, it is possible to provide a skin cleanser with a reduced feeling of tension after use.

In the present invention, the mass ratio of the structural unit (e) to the structural unit (f) constituting the water-soluble copolymer is preferably 1:99 to 60:40, more preferably 10:90 to 50:50, It is preferably 20:80 to 40:60.

The molar ratio of the structural unit (e) to the structural unit (f) constituting the water-soluble copolymer is preferably 1:99 to 71:29, more preferably 15:85 to 62:38, and still more preferably 29. : 71 to 52:48, more preferably 35:65 to 45:55.
By setting the mass ratio and the molar ratio of the structural unit (e) and the structural unit (f) in the water-soluble copolymer to be in the above ranges, a water-soluble copolymer that is more excellent in the effect of reducing the tension feeling can be obtained.

<2> Skin cleansing agent [1] Dosage form The skin cleansing agent refers to a composition containing a cleaning component, and is used for the purpose of removing skin dirt such as sebum. As described above, the skin cleansing agent has an effect of removing sebum present in the skin, and thus has a problem that it causes a feeling of tension on the skin after use.
The skin cleanser of the present invention is characterized by containing the above-mentioned water-soluble copolymer. According to the present invention, it is possible to reduce the feeling of skin tightness after use without impairing or improving the cleaning power inherent to the skin cleansing material.

The dosage form of the skin cleansing material of the present invention can be applied without particular limitation as long as it is a dosage form normally used for skin cleaning materials. Common skin cleansing agents include solid, powder, cream, liquid, and gel skin cleansing agents, but the present invention can be applied to any dosage form.

The content of the above-mentioned water-soluble copolymer in the skin cleanser whose dosage form is a liquid such as cream, liquid or gel is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass, More preferably, it is 1 to 3% by mass.
By setting the content of the above-mentioned water-soluble copolymer in the above range, it is possible to further reduce the feeling of tightness of the skin after use without impairing the cleaning power inherent to the skin cleansing agent.

∙ Skin cleansing materials can be divided into those that are used by lathering and those that are used without lathering. Regardless of which type of skin cleansing material is applied, the present invention can reduce the feeling of skin tension after use without impairing the inherent cleaning power of the skin cleansing material.

In the skin cleanser of the type used by foaming, the content of the above-mentioned water-soluble copolymer is 0.1% by mass or more, more preferably 0.5% by mass or more, more preferably from the viewpoint of improving the foaming quality. It is 0.8 mass% or more, More preferably, it is 1 mass% or more.
Further, from the viewpoint of reducing the feeling of skin slimness after use, the content of the above-mentioned water-soluble copolymer is preferably 20% by mass or less, more preferably 10% by mass or less, further preferably 3% by mass or less, Preferably it is 1 mass% or less.
As a type of skin cleansing agent used by foaming, a creamy skin cleansing agent is preferably mentioned.

In the skin cleanser of the type used without foaming, the content of the above-mentioned water-soluble copolymer is preferably 0.1 to 10% by mass, more preferably 0.8%, from the viewpoint of improving ease of spreading to the skin. It is 5 to 5% by mass, more preferably 0.6 to 3% by mass, and further preferably 0.7 to 2% by mass.
As a type of skin cleanser used without foaming, a gel-like skin cleanser is preferably used.

(2) Skin Cleanser Containing Surfactant While a skin cleanser containing a surfactant as a cleaning component has a strong detergency, it has a problem that the feeling of skin tightness after use is strong. Therefore, it is preferable to apply the present invention to a skin cleanser containing a surfactant.

The surfactant that can be contained in the skin cleanser of the present invention is not particularly limited as long as it is usually used in a skin cleanser, and includes ionic surfactants and nonionic surfactants. Any of them can be used.

As the ionic surfactant, any of an anionic surfactant, a cationic surfactant, an amphoteric surfactant and a nonionic surfactant can be used.

Examples of the anionic surfactant include fatty acid soaps such as fatty acid sodium, fatty acid potassium, and fatty acid triethanolamine, sodium lauryl sulfate, potassium lauryl sulfate, and triethanol lauryl sulfate, which may have a polyoxyethylene group. Polysulfuric acid ester salts that may have polyoxyethylene groups, such as amines, polyoxyethylene groups that may have polyoxyethylene groups, such as sodium lauryl phosphate, potassium lauryl phosphate, and lauryl phosphorus triethanolamine. Preferred examples include alkyl phosphorus ester salts and sulfosuccinic acid alkyl ester salts which may have an oxyethylene group.

Examples of the anionic surfactant include alkyltrimethylammonium salt, alkylpyridinium salt, distearyldimethylammonium dialkyldimethylammonium chloride, poly (N, N′-dimethyl-3,5-methylenepiperidinium chloride), Alkyl quaternary ammonium salts, alkyl dimethyl benzyl ammonium salts, alkyl isoquinolinium salts, dialkyl morpholinium salts, POE-alkyl amines, alkyl amine salts, polyamine fatty acid derivatives, amyl alcohol fatty acid derivatives, benzalkonium chloride, benzethonium chloride Etc. can be preferably exemplified.

Examples of amphoteric surfactants include imidazoline-based amphoteric surfactants and betaine-based surfactants.

Nonionic surfactants include glycerin fatty acid ester, polyglycerin fatty acid ester, polyoxyethylene glycerin fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbit fatty acid ester, polyoxyethylene alkylphenyl ether, Polyoxyethylene lanolin, lanolin alcohol, beeswax derivative, polyoxyethylene castor oil, hydrogenated castor oil, polyoxyethylene sterol, hydrogenated sterol, polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene fatty acid ester , Polyoxyethylene alkyl ether fatty acid ester, polyoxyethylene hydrogenated castor oil fatty acid ester Polyoxyethylene trimethylol propane fatty acid ester, polyethylene glycol fatty acid esters, sucrose fatty acid esters, polyoxyethylene polyoxypropylene block copolymer, it can be preferably exemplified organic modified silicone.

The content of these surfactants is not particularly limited, and can be appropriately set depending on the type of the surfactant.
Hereinafter, the skin cleansing agent in a form containing a fatty acid soap, a form containing a nonionic surfactant, and a gel-like form will be described more specifically.

(2-1) Skin Cleanser Containing Fatty Soap The present invention is applied to a skin cleanser containing a fatty acid soap, so that the high-quality foaming and creamy foam quality of the skin cleansing agent is not impaired. The feeling of tightness of the skin can be reduced.

The form of the skin cleanser containing fatty acid soap may be solid, liquid or cream, but is preferably liquid or cream. In particular, it is preferable to use a form of a creamy skin cleanser used by whipping.

The fatty acid constituting the fatty acid soap is not particularly limited as long as it can be applied to the skin cleanser, and may be saturated or unsaturated, and has 8 to 24 carbon atoms, particularly 10 to 22 carbon atoms. Those are preferred. Specific examples of preferable ones include lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, oleic acid, hydroxystearic acid, hydroxydecenoic acid, coconut oil fatty acid, reduced coconut oil fatty acid, beef tallow fatty acid, reduced beef tallow fatty acid, palm Examples include nuclear fatty acids. Among these fatty acids, it is preferable to contain one or more selected from myristic acid, palmitic acid and stearic acid from the viewpoints of foaming, safety and stability, and in particular myristic acid, palmitic acid and stearic acid. It is preferable to use three kinds of acids. Alkali agents that form salts with these higher fatty acids include alkali metal salts such as sodium and potassium, ammonium salts, monoethanolamine salts, diethanolamine salts, triethanolamine salts, 2-amino-2-methylpropanol, 2- Examples thereof include alkanolamine salts such as amino-2-methylpropanediol, and basic amino acid salts such as lysine and arginine.

The content of fatty acid contained in the skin cleanser is not particularly limited. In the case of a creamy skin cleanser, the fatty acid content is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, and even more preferably 30 to 50% by mass.

From the viewpoint of reducing the feeling of tension after use of the skin cleansing agent, the ratio of the above-mentioned water-soluble copolymer and fatty acid content is preferably 1: 500 to 1: 2, more preferably 1: 200 to 1: 3, More preferably, it is 1: 100 to 1: 5.
Further, from the viewpoint of improving the foaming property, the ratio of the above-mentioned water-soluble copolymer and fatty acid content is preferably 1: 200 to 1: 2, more preferably 1: 100 to 1: 5, still more preferably 1. : 50 to 1:10.
From the viewpoint of reducing the feeling of skin slimming after use, the ratio of the above-mentioned water-soluble copolymer and fatty acid content is preferably 1: 500 to 1:10, more preferably 1: 200 to 1:20. More preferably, the ratio is 1: 100 to 1:50.

(2-2) Skin Cleansing Agent Containing Nonionic Surfactant The present invention effectively provides a feeling of skin tension after use even when applied to a skin cleanser containing a nonionic surfactant. Can be reduced. As the nonionic surfactant, those described above can be used without limitation.

In the form containing a nonionic surfactant, the content of the water-soluble copolymer is preferably 0.1% by mass or more, and more preferably 0.5% by mass, from the viewpoint of reducing the feeling of tension after use. As mentioned above, More preferably, it is 1 mass% or more.
Further, from the viewpoint of improving detergency, the content of the water-soluble copolymer is preferably 0.5% by mass or more, more preferably 1% by mass or more, further preferably 2% by mass or more, and further preferably 3%. It is at least mass%.

From the viewpoint of reducing the feeling of tension after use of the skin cleansing agent, the ratio of the content of the above-mentioned water-soluble copolymer and nonionic surfactant is preferably 1:20 to 1: 0.5, more preferably 1. : 10 to 1: 0.7, more preferably 1: 5 to 1: 1.
Further, from the viewpoint of improving the detergency, the ratio of the mass content of the water-soluble copolymer and the nonionic surfactant is preferably 1:10 to 1: 0.5, more preferably 1: 5 to 1. : 0.5, more preferably 1: 3 to 1: 0.6, and still more preferably 1: 1.5 to 1: 0.7.

In addition, in the case of a gel-like skin cleansing agent containing a nonionic surfactant, from the viewpoint of improving the ease of spreading to the skin during use, the water-soluble copolymer and the nonionic surfactant described above are used. The ratio of the contained mass is preferably 1:15 to 1: 0.7, more preferably 1:10 to 1: 1, and still more preferably 1: 7 to 1: 3.

[3] Others The skin cleansing agent of the present invention can contain, in addition to the above-mentioned components, optional components that are usually used in external preparations for skin. Examples of such optional ingredients include macadamia nut oil, avocado oil, corn oil, olive oil, rapeseed oil, sesame oil, castor oil, safflower oil, cottonseed oil, jojoba oil, coconut oil, palm oil, liquid lanolin, and hardened coconut oil. Oil, wax, oils such as beeswax, molasses, hydrogenated castor oil, beeswax, candelilla wax, carnauba wax, ibotarou, lanolin, reduced lanolin, hard lanolin, jojoba wax; , Hydrocarbons such as microcrystalline wax; higher fatty acids such as oleic acid, isostearic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, undecylenic acid; cetyl alcohol, stearyl alcohol, isostearyl Higher alcohols such as alcohol, behenyl alcohol, octyldodecanol, myristyl alcohol, cetostearyl alcohol, etc .; cetyl isooctanoate, isopropyl myristate, hexyldecyl isostearate, cetyl lactate, diisostearyl malate, ethylene di-2-ethylhexanoate Glycol, neopentyl glycol dicaprate, glycerin di-2-heptylundecanoate, glycerol tri-2-ethylhexanoate, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, tetra-2-ethylhexane Synthetic ester oils such as acid pentane erythritol; chain polysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, and diphenylpolysiloxane; Cyclic polysiloxanes such as kutamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexanesiloxane; silicones such as amino-modified polysiloxane, polyether-modified polysiloxane, alkyl-modified polysiloxane, and fluorine-modified polysiloxane Oils such as oil; polyethylene glycol, glycerin, 1,3-butylene glycol, erythritol, sorbitol, xylitol, maltitol, propylene glycol, dipropylene glycol, diglycerin, isoprene glycol, 1,2-pentanediol, 2,4 -Polyhydric alcohols such as hexanediol, 1,2-hexanediol, 1,2-octanediol; sodium pyrrolidonecarboxylate, lactic acid, sodium lactate Moisturizing ingredients such as mud; powders such as mica, talc, kaolin, synthetic mica, calcium carbonate, magnesium carbonate, anhydrous silicic acid (silica), aluminum oxide, barium sulfate, etc., whose surface may be treated; Bengara, yellow iron oxide, black iron oxide, cobalt oxide, ultramarine, bitumen, titanium oxide, zinc oxide inorganic pigments that may be treated on the surface; titanium mica, fish phosphorus that may be treated on the surface Pearls such as foil and bismuth oxychloride; red 202, red 228, red 226, yellow 4, blue 404, yellow 5, red 505, red 230, which may be raked, Organic dyes such as Red No. 223, Orange No. 201, Red No. 213, Yellow No. 204, Yellow No. 203, Blue No. 1, Green No. 201, Purple No. 201, Red No. 204; Organic powders such as nylon powder and organopolysiloxane elastomers; paraaminobenzoic acid UV absorbers; anthranilic acid UV absorbers; salicylic acid UV absorbers; cinnamic acid UV absorbers; benzophenone UV absorbers Sugar-based UV absorbers; UV absorbers such as 2- (2′-hydroxy-5′-t-octylphenyl) benzotriazole and 4-methoxy-4′-t-butyldibenzoylmethane; ethanol, isopropanol, etc. Lower alcohols; vitamin B or its derivatives, vitamin B6 hydrochloride, vitamin B6 tripalmitate, vitamin B6 dioctanoate, vitamin B2 or a derivative thereof, vitamin B such as vitamin B12, vitamin B15 or a derivative thereof; α-tocopherol, β-tocopherol, γ-tocopherol, and damage Vitamin E such as E acetate, vitamin D, vitamin H, pantothenic acid, pantethine, vitamins etc. pyrroloquinoline quinone and the like; and antibacterial agents such as phenoxyethanol preferred examples.

The skin cleanser of the present invention can be produced by treating each of the above components according to a conventional method.

The present invention is preferably applied to a facial cleanser. According to the present invention, it is possible to provide a facial cleanser that does not feel the feeling of skin tightness after face washing.

A feature of the sunscreen cosmetic of the present invention that solves the fifth problem is that it contains the above four components [1] to [4] as essential components. Hereinafter, the components [1] to [4] will be described in detail.

<1> Component (A): Water-soluble copolymer [1] Hydrophobic monomer Component (A) is derived from the hydrophobic monomer represented by the general formula (1), (7) or (8). It is a water-soluble copolymer containing one or more structural units (hereinafter, sometimes simply referred to as “structural unit (7)”) as essential structural units.
In the present invention, the “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 (1), (7) or (8) will be described.

trimethylpentanoyl group

3,5,5-trimethylhexanoyl group and the like.

R24 and R25 in the general formula (15) are preferably a branched acyl group having 10 to 22 carbon atoms that does not include a ring structure.
The carbon number of the acyl group of R24 and R25 in the general formula (15) is 12 to 22, more preferably 14 to 20, and still more preferably 16 to 20.
The carbon number of the main chain of the acyl group of R24 and R25 in the general formula (15) is preferably 9 to 21, more preferably 12 to 20, and still more preferably 16 to 18.
Further, the number of branches in the acyl group of R24 and R25 in the general formula (15) is preferably 1 to 3, more preferably 1 or 2, and still more preferably 1.
Furthermore, in the acyl groups of R24 and R25 in the general formula (15), the position number of carbon in the main chain to which the branched chain is bonded is preferably as large as possible. Specifically, the branched chain is bonded to the carbon at the end of the main chain, preferably from the 1st to 3rd carbon, more preferably the 1st or 2nd carbon, and even more preferably the 1st carbon. It is preferable.

[2] Hydrophilic monomer Examples of the hydrophilic monomer constituting the water-soluble copolymer of the component (A) include a polymerizable carboxylic acid, the general formula (2), and the general formulas (9), (10), and (11). The compound represented by these can be used.

Furthermore, n in the general formula (2) is in the numerical range of 6 to 40.

(2-3) Hydrophilic monomer represented by general formula (9) As the hydrophilic monomer in the present invention, a hydrophilic monomer represented by the above general formula (9) may be used.

(2-4) Hydrophilic monomer represented by general formula (10) As the hydrophilic monomer in the present invention, a hydrophilic monomer represented by the above general formula (10) may be used.

(2-5) Hydrophilic monomer represented by general formula (11) As the hydrophilic monomer in the present invention, a hydrophilic monomer represented by the above general formula (11) may be used.

Specific examples of the monomer represented by the general formula (11) and salts thereof include compounds 1 to 11 and salts thereof.

As described above, the general formulas (2), (9), (10), and (11) can be used as the hydrophilic polymer in the present invention.
In a preferred embodiment of the present invention, the water-soluble copolymer contains the structural unit 2 derived from the general formula (2).

(Methoxymethacrylic acid PEG-23 / glyceryl methacrylate) is a structural unit (g) in which R24 and R25 are 16-methylheptadecanoyl among the hydrophobic monomers represented by the general formula (15). It mainly contains a structural unit (g) derived from a hydrophobic monomer as a group.
Further, among the hydrophilic monomers represented by the general formula (2), the structural unit (h) is derived from a hydrophilic monomer in which R4 is a methyl group, R5 is an ethylene group, R6 is a methyl group, and n is 23. The structural unit (h) is mainly included.

In the present invention, the proportion of the structural unit (g) in all the structural units in the water-soluble copolymer is preferably 1 to 50% by mass, more preferably 5 to 40% by mass, and 10 to 30% by mass.
By setting the proportion of the structural unit (g) in the water-soluble copolymer within the above range, it is possible to provide a sunscreen cosmetic that is excellent in moisturizing feeling and reduced in stickiness.

In the present invention, the proportion of the structural unit (h) in all the structural units in the water-soluble copolymer is preferably 50 to 99% by mass, more preferably 60 to 95% by mass, and 70 to 90% by mass.
By setting the proportion of the structural unit (h) in the water-soluble copolymer within the above range, it is possible to provide a sunscreen cosmetic that is excellent in moisturizing feeling and reduced in stickiness.

In the present invention, the mass ratio of the structural unit (g) to the structural unit (h) constituting the water-soluble copolymer is preferably 5:95 to 50:50, more preferably 10:90 to 45:55, The ratio is preferably 20:80 to 40:60, more preferably 25:75 to 35:65.

The molar ratio of the structural unit (g) to the structural unit (h) constituting the water-soluble copolymer is preferably 8:92 to 62:38, more preferably 15:85 to 57:43, and still more preferably 29. : 71 to 52:48, more preferably 35:65 to 46:54.
By setting the mass ratio and molar ratio of the structural unit (g) and the structural unit (h) in the water-soluble copolymer to be in the above ranges, the feeling of use of the sunscreen cosmetic can be further improved.

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, still more preferably 50,000 to 70,000, still more preferably. 57000-66000.

The content of the above water-soluble copolymer is not particularly limited, but is usually 0.001 to 15% by mass, preferably 0.01 to 10% by mass.

<2> Component (B): Polyglycerin fatty acid ester The sunscreen cosmetic of the present invention is obtained by ester condensation of one molecule of polyglycerol having a polymerization degree of 10 and 2 to 5 molecules of fatty acid having 16 or more carbon atoms. It contains polyglycerin fatty acid ester as component (B).

The fatty acid having 16 or more carbon atoms constituting the polyglycerol fatty acid ester of the component (B) may have a branched chain, and may be saturated or unsaturated.
Preferred examples include oleic acid and isostearic acid.
The number of fatty acid molecules to be ester-bonded to one molecule of polyglycerol may be 2 to 5, and preferably 5 molecules.
In the present invention, polyglyceryl-10 pentastearate is particularly preferably used as component (B).

The content of the polyglycerin fatty acid ester of component (B) can usually be 0.1 to 10% by mass.
Further, from the viewpoint of improving the emulsion stability, the content of the component (B) is 0.3% by mass or more, more preferably 0.5% by mass, and still more preferably 0.7% by mass or more.
Furthermore, from the viewpoint of suppressing stickiness, the content of the component (B) is preferably 7% by mass or less, more preferably 5% by mass or less, and further preferably 3% by mass or less.

<3> Component (C) ... Ionic Surfactant The sunscreen cosmetic of the present invention contains an ionic surfactant as the component (C). The ionic surfactant is not particularly limited as long as it is used in cosmetics, and any of an anionic surfactant, a cationic surfactant and an amphoteric surfactant can be used.

Examples of the anionic surfactant include fatty acid soaps such as fatty acid sodium, fatty acid potassium, and fatty acid triethanolamine, sodium lauryl sulfate, potassium lauryl sulfate, triethanolamine that may have a polyoxyethylene group. Alkyl sulfate ester salt, acyl lactate, which may have a polyoxyethylene group, sodium lauryl phosphate, potassium lauryl phosphate, lauryl phosphorus triethanolamine, etc. Preferred examples thereof include alkyl phosphorus ester salts and sulfosuccinic acid alkyl ester salts which may have a polyoxyethylene group.

Examples of the cationic surfactant include alkyltrimethylammonium salt, alkylpyridinium salt, distearyldimethylammonium dialkyldimethylammonium salt, poly (N, N′-dimethyl-3,5-methylenepiperidinium chloride), alkyl Quaternary ammonium salt, alkyldimethylbenzylammonium salt, alkylisoquinolinium salt, dialkyl morpholinium salt, POE-alkylamine, alkylamine salt, polyamine fatty acid derivative, amyl alcohol fatty acid derivative, benzalkonium chloride, benzethonium chloride, etc. Can be preferably exemplified.

Among the above surfactants, an anionic surfactant is preferably used as the component (C), and acyl lactate is more preferably used.

As the acyl lactate, a sodium salt is preferable, and specific examples include sodium lauroyl lactate, isostearoyl sodium lactate, and stearoyl sodium lactate.

The content of the ionic surfactant is not particularly limited, and is usually 0.01 to 2.0% by mass, more preferably 0.1 to 1% by mass.
Further, from the viewpoint of improving the emulsion stability, the content of the ionic surfactant is preferably 0.05% by mass or more, more preferably 0.07% by mass or more, and further preferably 0.1% by mass or more. To do.
Furthermore, from the viewpoint of suppressing stickiness, the content of the ionic surfactant is preferably 1.5% by mass or less, more preferably 1% by mass or less, and further preferably 0.5% by mass or less.

<4> Component (D)... Ultraviolet scattering agent / ultraviolet absorber The sunscreen cosmetic of the present invention contains an ultraviolet scattering agent and / or an ultraviolet absorber as the component (D).

The term “ultraviolet scattering agent” refers to a particulate metal oxide that functions to scatter ultraviolet rays, and the type thereof is not particularly limited as long as it can be blended in an emulsified cosmetic. Examples of the metal oxide include titanium dioxide, zinc oxide, zirconium oxide, cerium oxide and the like.

The content of the ultraviolet scattering agent is not particularly limited, and is usually 0.01 to 20% by mass, more preferably 0.1 to 15% by mass, and further preferably 1 to 10% by mass.

The ultraviolet scattering agent has a particle size referred to as fine particles in the technical field. For example, the primary particle size by electron microscope observation is usually 5 nm or more, preferably 10 nm or more, and usually 100 nm or less, preferably 80 nm or less. belongs to.
Since the ultraviolet scattering agent used in the present invention is excellent in the ultraviolet scattering effect, it preferably contains at least one selected from the group consisting of fine particle titanium dioxide and fine particle zinc oxide.

The ultraviolet light scattering agent used in the present invention can be prepared by a conventional method such as thermal decomposition of the corresponding metal salt in the gas phase, but since there are many commercial products, the commercial products are used as they are. You can also. Specific examples of such commercially available products include “MTY-110M3S” (manufactured by Teika), “MTY-02” (manufactured by Teica), “MT-100TV” ( (Taika Co., Ltd.), “MT-500HSA” (Taika Co., Ltd.), “MT-100T” (Taika Co., Ltd.), “MT-01” (Taika Co., Ltd.), “MT-10EX” ”(Manufactured by Teika),“ MT-05 ”(manufactured by Teika),“ MT-100Z ”(manufactured by Teica),“ MT-150EX ”(manufactured by Teica),“ MT -100AQ "(manufactured by Teika)," MT-100WP "(manufactured by Teika)," MT-100SA "(manufactured by Teica)," MT-500B "(manufactured by Teica), “MT-500SA” (manufactured by Teika Co., Ltd., “MT-600B”) ) "MT-500SAS" (manufactured by Teika Co., Ltd.), "Taipeke CR-50" (manufactured by Ishihara Sangyo Co., Ltd.), "Taipeke TTO-M-1" (Ishihara Sangyo Co., Ltd.) "Taipeke TTO-V4" (Ishihara Sangyo Co., Ltd.), "ST-455" (Titanium Industry Co., Ltd.), "STT-65C-S" (Titanium Industry Co., Ltd.), "STT- 30EHS "(manufactured by Titanium Industry Co., Ltd.)," Bayer Titanium R-KB-1 "(manufactured by Bayer) and the like.

Further, as fine particle zinc oxide, “MZ-300” (manufactured by Teika), “MZY-303S” (manufactured by Teica), “MZ-306X” (manufactured by Teica), “MZ-500” "(Manufactured by Teica)," MZY-505S "(manufactured by Teica)," MZ-506X "(manufactured by Teica)," MZ-510HPSX "(manufactured by Teica)," WSX -MZ-700 "(manufactured by Teika Co., Ltd.)," SAMT-UFZO-450 "(manufactured by Miyoshi Kasei Co., Ltd.)," SAMT-UFZO-500 "(manufactured by Miyoshi Kasei Co., Ltd.)," FZO-50 " (Manufactured by Ishihara Sangyo Co., Ltd.), “Maxlite ZS-032” (manufactured by Showa Denko KK), “Maxlite ZS-032D” (manufactured by Showa Denko KK) and the like.

In the present invention, the surface of the UV scattering agent is preferably coated with an inorganic compound such as silica or alumina, or an organic compound such as sodium polyacrylate, fatty acid metal soap, or silicone.

The ultraviolet scattering agent is preferably water-dispersible. Since the water-dispersible ultraviolet scattering agent is uniformly dispersed in the aqueous phase, the sunscreen cosmetic of the present invention having such a form has an excellent ultraviolet protection function.

A preferable example of the water-dispersible ultraviolet scattering agent is an ultraviolet scattering agent whose surface is coated with a hydrophilic compound.
As such a water dispersible ultraviolet scattering agent, an ultraviolet scattering agent that has been surface-treated with sodium polyacrylate is preferable. The sunscreen cosmetic of the present invention containing an ultraviolet light scattering agent surface-treated with sodium polyacrylate as the component (D) has excellent dispersibility and an excellent ultraviolet protection function.

The ultraviolet absorber is not particularly limited as long as it is an ultraviolet absorber that can be usually blended into an emulsified cosmetic, but in order to absorb ultraviolet rays having a wide wavelength range, it absorbs ultraviolet rays having a wavelength of 320 to 400 nm (A region). It is preferable to include a -A absorber and a UV-B absorber that absorbs ultraviolet rays having a wavelength of 290 to 320 nm (B region).
The content of the ultraviolet absorber is not particularly limited and is usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 1% by mass or more, and usually 20% by mass or less, preferably 15%. It is 10 mass% or less, More preferably, it is 10 mass% or less.

UV-A absorbers include 2-hydroxy-4-methoxybenzophenone, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, dimethoxybenzylidenedioxoimidazolidinepropionate 2-ethylhexyl, bis (reslucinyl) Examples include compounds such as triazine, methylenebisbenzotriazolyltetramethylbutylphenol, hexyl diethylaminohydroxybenzoyl benzoate, t-butylmethoxydibenzoylmethane and the like. Of these, hexyl diethylaminohydroxybenzoyl benzoate and t-butylmethoxydibenzoylmethane are particularly preferred because of their excellent ultraviolet absorbing ability. Since these compounds have commercial products, commercial products can be used as they are. Specific commercial products include “Ubinal A Plus Granular” (hexyl diethylaminohydroxybenzoyl benzoate, manufactured by BASF) and “Pulsol 1789” (t-butylmethoxybenzoylmethane, manufactured by DSM).

The content of the UV-A absorber is usually 0.01% by mass or more, preferably 0.1% by mass or more, and usually 5% by mass or less, preferably 3% by mass or less.

Specific examples of UV-B absorbers include 2-methoxyhexyl paramethoxycinnamate, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, dimethicodiethylbenzalmalonate, 2,4,6-trianilino. -P- (carbo-2'-ethylhexyl-1'-oxy) -1,3,5-triazine, 2-hydroxy-4-methoxybenzophenone, homomenthyl salicylate, octyl salicylate and the like. Since these compounds have commercial products, commercial products can be used as they are. Specific commercial products include “Ubinal MC80” (2-ethylhexyl paramethoxycinnamate, manufactured by BASF), “Ubinal T150” (2,4,6-trianilino-p- (carbo-2′-ethylhexyl-1′-). Oxy) -1,3,5-triazine (BASF), “Ubinal M40” (2-hydroxy-4-methoxybenzophenone, BASF), “Pulsol SLX” (Dimethicodiethylbenzalmalonate, DSM), Examples include “Parsol 340” (2-ethylhexyl 2-cyano-3,3-diphenylacrylate, manufactured by DSM), “Parsol HMS” (homogentyl salicylate, manufactured by DSM), and “Pulsol EMS” (octyl salicylate, manufactured by DSM). .

The content of the UV-B absorber is usually 0.1% by mass or more, preferably 0.5% by mass or more, and usually 10% by mass or less, preferably 7% by mass or less.

<5> Other composition The component contained in an oil phase and a water phase is not specifically limited.
Examples of the oil agent constituting the oil phase include liquid oils and fats, solid oils and fats, waxes, hydrocarbon oils, higher fatty acids, higher alcohols, synthetic ester oils, silicone oils, and the like.

One or more oil agents can be used.

The sunscreen cosmetic of the present invention may be blended with optional additives that are usually blended in cosmetics within a range that does not impair the effects of the present invention. Examples of such additive components include humectants such as polyethylene glycol, glycerin, 1,3-butylene glycol, erythritol, sorbitol, xylitol, and maltitol; lower alcohols such as ethanol; butylhydroxytoluene, tocopherol, and phytin. Antioxidants; antibacterial agents such as benzoic acid, salicylic acid, sorbic acid, paraoxybenzoic acid alkyl ester, hexachlorophene; organic acids such as acyl sarcosine acid (eg, lauroyl sarcosine sodium), glutathione, citric acid, malic acid, tartaric acid, lactic acid Vitamin A and its derivatives, vitamin B6 hydrochloride, vitamin B6 tripalmitate, vitamin B6 dioctanoate, vitamin B2 and its derivatives, vitamin B12, vitamin B15 and its derivatives Vitamins B, α-tocopherol, β-tocopherol, γ-tocopherol, vitamin E such as vitamin E acetate, vitamin D, vitamin H, pantothenic acid, panthetin, nicotinic acid amide, nicotinic acid benzyl; γ-oryzanol, allantoin, glycyrrhizic acid (salt), glycyrrhetinic acid and its derivatives, tranexamic acid and its derivatives [for tranexamic acid derivatives, dimers of tranexamic acid (for example, trans-4- (trans-aminomethylcyclohexane hydrochloride) Carbonyl) aminomethylcyclohexanecarboxylic acid, etc.), esters of tranexamic acid and hydroquinone (for example, trans-4-aminomethylcyclohexanecarboxylic acid 4′-hydroxyphenyl ester, etc.), tranexam Esters of acid and gentisic acid (eg, 2- (trans-4-aminomethylcyclohexylcarbonyloxy) -5-hydroxybenzoic acid and its salts, etc.), amides of tranexamic acid (eg, trans-4-aminomethyl) Cicohexanecarboxylic acid methylamide and its salt, trans-4- (P-methoxyvinzoyl) aminomethylcyclohexanecarboxylic acid and its salt, trans-4-guanidinomethylcyclohexanecarboxylic acid and its salt, etc.)], hinokitiol, bisabolol, Eucalptone, thymol, inositol, saikosaponin, carrot saponin, hechima saponin, muclodisaponin and other saponins, pantothenyl ethyl ether, ethinyl estradiol, tranexamic acid, arbutin, cephala Various drugs such as tin, placenta extract; borage, clara, corn, orange, sage, yarrow, mallow, thyme, thyme, spruce, spruce, birch, horsetail, loofah, maronier, yukinoshita, arnica, lily, mugwort, peonies, aloe Extracts of plants such as gardenia, gardenia and sawara; pigments; porous and / or water-absorbing powders (eg starches derived from corn, potato, etc., anhydrous silicic acid, talc, kaolin, magnesium aluminum silicate, calcium alginate Etc.); neutralizers; preservatives; fragrances; pigments and the like.

The sunscreen cosmetic of the present invention can be produced, for example, by the following method.
The oil agent, component (B), and other oil phase components are mixed and dissolved by heating to prepare a mixture of oil phase components. When the ultraviolet scattering agent (component (D)) is contained, the ultraviolet scattering agent is added to the mixture and dispersed using a disper.
Next, the water phase component and the component (C) are mixed, and the mixture of the oil phase component is added to the heated portion and emulsified with a homogenizer. After emulsification, the sunscreen cosmetic of the present invention is produced by adding component (A) and, if necessary, a water-dispersible UV scattering agent (component (D)) and cooling with stirring and mixing. Can do.

<1> Coating with a sea-island structure A sea-island structure is that two types of incompatible polymers cause phase separation, and a continuous phase containing one polymer is dotted with a dispersed phase containing the other polymer. It refers to the structure. The continuous phase in the sea-island structure is called the sea phase, the dispersed phase is called the island phase, and the particles in the dispersed phase are called island particles.

The film of the present invention has a sea-island structure in which island particles containing an amphiphilic copolymer are dispersed in a sea phase containing an aqueous gel formed by a water-soluble polymer.
The amphiphilic copolymer contained in the island particles has the structural unit (i) and the structural unit (j) as essential structural units.
The structural unit (i) is one or more structural units derived from a hydrophobic monomer, and the structural unit (j) is one or more structural units derived from a hydrophilic monomer. .
The coating film of the present invention having such a structural characteristic has a milk-like feel including an oily agent, despite being mainly composed of an aqueous component.
Hereinafter, the coating film of the present invention will be described in detail.

<1-1> Island Particles In the present invention, the amphiphilic copolymer contained in the island particles having a sea-island structure includes a structural unit (i) derived from the hydrophobic monomer and a structural unit derived from the hydrophilic monomer ( j) as an essential constituent unit.
As the amphiphilic copolymer in the present invention, it is preferable to use a copolymer containing structural units derived from a hydrophobic monomer and a hydrophilic monomer described in [1] and [2] below.

[1] Hydrophobic monomer In the present invention, a structural unit derived from the hydrophobic monomer represented by the general formula (1), (7) or (8) (hereinafter simply referred to as “structural unit (7)”). It is preferable to use an amphiphilic copolymer (also referred to as an acrylic acid-based amphiphilic copolymer) containing one or more of the essential constituent units.
In the present invention, the “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 (1), (7) or (8) will be described.

Here, examples of the alkyl group represented by R1 and R16 include a methyl group, an ethyl group, a propyl group, an isopropyl group, and a cyclopropyl group. In the present invention, R3 is preferably a hydrogen atom or a methyl group.

In a preferred embodiment of the present invention, in the general formulas (1) and (8), R2, R3, R17, R18, and R19 may be the same or different, do not include a ring structure, and have a branch. An acyl group having 10 to 22 carbon atoms, or an acyl group having 6 to 9 carbon atoms having two or more branches that does not contain a ring structure.

trimethylpentanoyl group

3,5,5-trimethylhexanoyl group and the like.

In the present invention, it is particularly preferable to use an amphiphilic copolymer containing the structural unit (1).
In a more preferred embodiment of the present invention, the hydrophobic monomer represented by the general formula (1) is a hydrophobic monomer represented by the general formula (15).

(2-1) Polymerizable carboxylic acid In the present invention, the polymerizable carboxylic acid or a salt thereof specifically includes acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid and its sodium salt, potassium salt, Examples thereof include ammonium salts and amine salts. Among these, acrylic acid, methacrylic acid and salts thereof are particularly preferable because of high polymerizability. When a structural unit derived from a salt of a polymerizable carboxylic acid is introduced into the amphiphilic copolymer of the present invention, the polymerizable carboxylic acid may be converted into a salt in advance, and a polymerization reaction may be performed. A structural unit derived from a basic carboxylic acid may be derived into an amphiphilic copolymer and then neutralized with a base to form a salt.

In the general formula (2), examples of the alkyl group represented by R4 include a methyl group, an ethyl group, a propyl group, an isopropyl group, and a cyclopropyl group. In the present invention, R6 is preferably a hydrogen atom or a methyl group.

Furthermore, n in the general formula (2) is in the numerical range of 6 to 40.

(2-4) Hydrophilic monomer represented by general formula (9) As the hydrophilic monomer in the present invention, a hydrophilic monomer represented by general formula (10) may be used.

In the monomer of the general formula (11), the amino acid of the amino acid residue represented by R23 is not particularly limited as long as it is a commonly known amino acid. Specifically, glycine, alanine, glutamine, lysine, Arginine etc. are illustrated. Of these, lysine residues are particularly preferred because the resulting amphiphilic copolymer is excellent in the skin barrier recovery effect.

In addition, the polyamine in the polyamine residue represented by R23 means an amine having two or more amino groups that may be substituted with an alkyl group in the same molecule, and specifically includes diamine, triamine, tetraamine. Or the amine by which the hydrogen atom of these amino groups is substituted by the alkyl group is illustrated. Among these, diamine is preferable because the feeling of use of the external preparation for skin containing the obtained amphiphilic copolymer is particularly excellent, and as a particularly preferable specific example, ethylenediamine, Examples include 1,4-diamino-n-butane and 1,6-diamino-n-hexane.

Although it does not specifically limit as a salt of the monomer represented by General formula (11), Specifically, the sodium salt, potassium salt, ammonium salt, amine salt, etc. which neutralized the acid part with the base, Examples thereof include hydrochlorides, sulfates, nitrates, phosphates, citrates, oxalates, carbonates, etc., in which the amino group is neutralized with an acid. When the structural unit derived from the salt of the monomer represented by the general formula (11) is introduced into the amphiphilic copolymer of the present invention, the monomer represented by the general formula (11) is previously converted into a salt, and the polymerization reaction is performed. Alternatively, the structural unit derived from the monomer represented by the general formula (11) may be derived into an amphiphilic copolymer by a polymerization reaction, and then neutralized to form a salt.

As described above, the general formulas (2), (9), (10), and (11) can be used as the hydrophilic polymer in the present invention.
In a preferred embodiment of the present invention, the amphiphilic copolymer comprises the structural unit (2) derived from the general formula (2).

[3] Amphiphilic copolymer In the present invention, an acrylic acid-based amphiphilic copolymer having the structural unit (1) and the structural unit (2) can be preferably used. More preferably, an acrylic acid-based amphiphilic copolymer having the structural unit (15) and the structural unit (2) is used.
Of these acrylic acid-based amphiphilic copolymers, a (methoxy PEG-23 methacrylate / glyceryl methacrylate) is particularly preferably used.
By containing such an acrylic acid-based amphiphilic copolymer, the moisture retention and flexibility of the coating can be improved.

(Methoxymethacrylate PEG-23 / glyceryl methacrylate diisostearate) copolymer is a structural unit (i) in which R24 and R25 are 16-methylheptadecanoyl among the hydrophobic monomers represented by the general formula (15). It mainly contains a structural unit (i) derived from a hydrophobic monomer as a group.
In addition, as the structural unit (j), among the hydrophilic monomers represented by the general formula (2), R4 is a methyl group, R5 is an ethylene group, R6 is a methyl group, and n is 23. The structural unit (j) is mainly included.

As the amphiphilic copolymer in the present invention, an existing copolymer can be used in addition to the above-mentioned copolymer. Specifically, the following existing copolymers can be used as the amphiphilic copolymer.
That is, polyquaternium-51 (a copolymer containing 2-methacryloyloxyethyl phosphorylcholine and butyl methacrylate in a molar ratio of approximately 8: 2), polyquaternium-61 (2-methacryloyloxyethyl phosphorylcholine and stearyl methacrylate approximately 3: 7). A glyceryl amidoethyl methacrylate / stearyl methacrylate copolymer (glyceryl-N- (2-methacryloyloxyethyl) carbamate and stearyl methacrylate in a molar ratio of approximately 6: 4), Copolymer having a weight average molecular weight of about 40,000), PEG / PPG / polybutylene glycol-8 / 5/3 glycerin, (hydrolyzed silk / PGpropylmethylsilanediol) crosspolymer (N- [2-hydroxy-3- [ 3 (Hydroxymethylsilyl) propoxy] propyl] hydrolyzed silylated copolymer), (eicosane diacid / tetradecanedioic acid) polyglyceryl-10 (eicosane diacid, tetradecanedioic acid dibasic acid and average degree of polymerization) 10 oligomers of polyglycerin), (glycerin / oxybutylene) copolymer stearyl (polymer having HLB of 18.0, which was obtained by simultaneous reaction of stearyl alcohol with glycidol and tetrahydrofuran), polyquaternium-7 (dimethyl chloride) Copolymer of diallylammonium and acrylamide), polyquaternium-39 (acrylic acid, dimethyldiallylammonium chloride and acrylamide terpolymer), (Na acrylate / acryloyldimethyltaurine) copolymer You can use existing copolymer of copolymer) and the like of sodium and acryloyl sodium taurate acrylate.
Of these, polyquaternium-51, polyquaternium-61, and (glyceryl amidoethyl methacrylate / stearyl methacrylate) copolymers can be particularly preferably exemplified.

In the present invention, the ratio of the structural unit (i) to the total structural units in the amphiphilic copolymer is preferably 1 to 50% by mass, more preferably 5 to 40% by mass, and 10 to 30% by mass.
By setting the proportion of the structural unit (i) in the amphiphilic copolymer within the above range, the moisture retention and flexibility of the coating of the present invention can be improved.

In the present invention, the proportion of the structural unit (j) in all the structural units in the amphiphilic copolymer is preferably 50 to 99% by mass, more preferably 60 to 95% by mass, and 70 to 90% by mass.
By setting the proportion of the structural unit (j) in the amphiphilic copolymer within the above range, the moisture retention and flexibility of the coating of the present invention can be improved.

In the present invention, the mass ratio of the structural unit (i) and the structural unit (j) constituting the amphiphilic copolymer is preferably 5:95 to 50:50, more preferably 10:90 to 45:55, More preferably, it is 20:80 to 40:60, and more preferably 25:75 to 35:65.
By setting the mass ratio of the structural unit (i) and the structural unit (j) in the amphiphilic copolymer within the above range, the moisture retention and flexibility of the coating of the present invention can be improved.

In the present invention, the molar ratio of the structural unit (i) to the structural unit (j) constituting the amphiphilic copolymer is preferably 8:92 to 62:38, more preferably 15:85 to 57:43, More preferably, it is 29:71 to 52:48, and more preferably 35:65 to 46:54.
By setting the molar ratio of the structural unit (i) and the structural unit (j) in the amphiphilic copolymer within the above range, the moisture retention and flexibility of the coating of the present invention can be improved.

In the present invention, the average molecular weight of the amphiphilic 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, still more preferably 50,000 to 70,000, still more preferably. Is 57000-66000.
By setting the molecular weight of the amphiphilic copolymer in the above range, the elasticity of the coating of the present invention can be improved and the stickiness can be suppressed.
In addition, an average molecular weight means here the weight average molecular weight of polystyrene conversion measured by GPC.

<1-2> Sea phase The above-mentioned island particles are dispersed in the sea phase of the aqueous gel. In the present invention, the aqueous gel is formed of a water-soluble polymer and / or a salt thereof and water hydrated in the water-soluble polymer.
The water-soluble polymer and / or salt thereof forming the aqueous gel is not particularly limited as long as the phase containing the amphiphilic copolymer can be dispersed as island particles, but is preferably an acrylic acid-based water-soluble polymer or water-soluble polymer. One or more water-soluble polymers selected from the group consisting of peptides and water-soluble polysaccharides and / or salts thereof can be used.

As the acrylic acid-based water-soluble polymer, a non-crosslinked acrylic acid polymer or an acrylic acid copolymer which may be crosslinked can be particularly preferably exemplified. The non-crosslinked acrylic acid polymer is preferably exemplified by sodium polyacrylate, and the cross-linked acrylic acid copolymer may be sodium polyacrylate, (acrylates / alkyl acrylate (C10 -30)) Cross polymers can be preferably exemplified.
A preferable example of the water-soluble polypeptide is sodium polyglutamate.
As said water-soluble polysaccharide, a xanthan gum and a white jellyfish polysaccharide can be illustrated preferably. Particularly preferably, xanthan gum is used as the water-soluble polysaccharide.
By using such a water-soluble polymer and / or a salt thereof, the moisture retention and flexibility of the coating of the present invention can be improved.

<1-3> Sea-island structure The coating of the present invention has a sea-island structure in which an island phase containing an amphiphilic copolymer is dispersed in a sea phase containing an aqueous gel.
In the film having the sea-island structure of the present invention, the area ratio of the sea phase to the island phase is preferably 2: 8 to 10: 1, more preferably 3: 7 to 9: 1, and further preferably 6: 4 to 7. : 3.
The coating film of the present invention in which the area ratio of the sea phase to the island phase is in the above range is excellent in elasticity, less sticky, and excellent in moisture retention and flexibility.

In a preferred embodiment of the present invention, the average major axis / minor axis ratio of the island particles is preferably 0.6 or more, more preferably 0.7 or more, still more preferably 0.8 or more, and further preferably 0.9 or more. It is.
By setting the average major axis / minor axis ratio of the island particles in the above range, the moisture retention and flexibility of the coating of the present invention can be improved.
The average major axis / minor axis ratio can be measured by observing the composition under a microscope. Specifically, the composition can be obtained by observing the composition under a microscope, measuring the major axis / minor axis ratio of 100 island particles, and arithmetically averaging them.

In a preferred embodiment of the present invention, the ratio of the major axis to the minor axis ratio of all island particles contained in the coating is less than 0.6, more preferably less than 0.7, and more preferably less than 0.8. The abundance ratio is 10% or less.
In a more preferred embodiment of the present invention, the proportion of the island particles having a major axis / minor axis ratio of less than 0.8 is 5% or less, more preferably 1% or less, in all of the island particles contained in the composition. is there.
The film of the present invention in such an embodiment is excellent in moisture retention and flexibility.

In a preferred embodiment of the present invention, the number particle size distribution of island particles having an average particle diameter of 0.5 to 10 μm, more preferably island particles having an average particle diameter of 1 to 5 μm is 80% or more.
In a further preferred embodiment of the present invention, the number particle size distribution of island particles having an average particle diameter of 1 to 5 μm is 85% or more, more preferably 90% or more.
By setting the number particle size distribution of island particles having such a small particle diameter within the above range, the moisture retention and flexibility of the coating of the present invention can be further improved.
The average particle size of the island particles can be measured by observing the composition with a microscope. Specifically, the composition can be obtained by measuring the major axis and minor axis of the island particles by microscopic observation and arithmetically averaging them.

The coating film of the present invention can contain any component usually used in a skin external preparation. Such components include oils / waxes, hydrocarbons, higher fatty acids, higher alcohols, synthetic ester oils, silicone oils, surfactants, polyhydric alcohols, moisturizing ingredients, thickening agents. Agents, powders, inorganic pigments, organic dyes, organic powders, ultraviolet absorbers, lower alcohols, vitamins, polymers having a biologically similar structure, and the like.

Examples of oils and waxes include macadamia nut oil, avocado oil, corn oil, olive oil, rapeseed oil, sesame oil, castor oil, safflower oil, cottonseed oil, jojoba oil, coconut oil, palm oil, liquid lanolin, hardened coconut oil, hardened Oil, mole, hardened castor oil, beeswax, candelilla wax, carnauba wax, ibotarou, lanolin, reduced lanolin, hard lanolin, jojoba wax, etc.
Examples of the hydrocarbons include liquid paraffin, squalane, pristane, ozokerite, paraffin, ceresin, petrolatum, and microcrystalline wax.

Examples of higher fatty acids include oleic acid, isostearic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, undecylenic acid, etc.
Examples of higher alcohols include cetyl alcohol, stearyl alcohol, isostearyl alcohol, behenyl alcohol, octyldodecanol, myristyl alcohol, cetostearyl alcohol, and the like.
Synthetic ester oils include, for example, cetyl isooctanoate, isopropyl myristate, hexyldecyl isostearate, diisopropyl adipate, di-2-ethylhexyl sebacate, cetyl lactate, diisostearyl malate, ethylene di-2-ethylhexanoate Glycol, neopentyl glycol dicaprate, glycerin di-2-heptylundecanoate, glycerol tri-2-ethylhexanoate, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, tetra-2-ethylhexane Acid pentane erythritol, etc.
Examples of silicone oils include chain polysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane, diphenylpolysiloxane, cyclic polysiloxanes such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexanesiloxane, amino Examples thereof include silicone oils such as modified polysiloxane, polyether-modified polysiloxane, alkyl-modified polysiloxane, and fluorine-modified polysiloxane.

Surfactants may be either anionic surfactants or nonionic surfactants.
Examples of anionic surfactants include fatty acid soap (sodium laurate, sodium palmitate, etc.), potassium lauryl sulfate, alkyl sulfate triethanolamine ether, and the like.
Nonionic surfactants include, for example, sorbitan fatty acid esters (such as sorbitan monostearate and sorbitan sesquioleate), glycerin fatty acids (such as glyceryl monostearate), and propylene glycol fatty acid esters (such as propylene glycol monostearate). ), Hardened castor oil derivative, glycerin alkyl ether, POE sorbitan fatty acid esters (POE sorbitan monooleate, polyoxyethylene sorbitan monostearate, etc.), POE sorbite fatty acid esters (POE-sorbite monolaurate, etc.), POE glycerin Fatty acid esters (POE-glycerol monoisostearate, etc.), POE fatty acid esters (polyethylene glycol monooleate, POE distearate, etc.), POE alkyl Ethers (POE2-octyldodecyl ether, etc.), POE alkylphenyl ethers (POE nonylphenyl ether, etc.), Pluronic types, POE / POP alkyl ethers (POE / POP2-decyltetradecyl ether, etc.), Tetronics, POE castor oil / hardened castor oil derivatives (POE castor oil, POE hardened castor oil, etc.), sucrose fatty acid ester, alkyl glucoside and the like can be mentioned.

Examples of polyhydric alcohols include polyethylene glycol, erythritol, xylitol, propylene glycol, dipropylene glycol, isoprene glycol, 1,2-pentanediol, 2,4-hexylene glycol, 1,2-hexanediol, 1,2 -Octanediol, etc.
Examples of moisturizing ingredients include sodium pyrrolidonecarboxylate, lactic acid, sodium lactate and the like,
Examples of thickeners include guar gum, quince seed, carrageenan, galactan, gum arabic, pectin, mannan, starch, curdlan, methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, methyl hydroxypropyl cellulose, chondroitin sulfate, dermatan sulfate, glycogen, heparan. Sulfuric acid, hyaluronic acid, sodium hyaluronate, tragacanth gum, keratan sulfate, chondroitin, mucoitin sulfate, hydroxyethyl guar gum, carboxymethyl guar gum, dextran, kerato sulfate, locust bean gum, succinoglucan, caronic acid, chitin,
Examples include chitosan, carboxymethyl chitin, agar, polyvinyl alcohol, polyvinyl pyrrolidone, carboxyvinyl polymer, polyethylene glycol, bentonite and the like.

Examples of powders include mica, talc, kaolin, synthetic mica, calcium carbonate, magnesium carbonate, anhydrous silicic acid (silica), aluminum oxide, barium sulfate, etc., whose surface may be treated.
As the inorganic pigments, for example, bengara, yellow iron oxide, black iron oxide, cobalt oxide, ultramarine, bitumen, titanium oxide, zinc oxide, etc., whose surface may be treated, are mentioned,
As organic pigments, the surface may be treated, pearl agents such as titanium mica, fish phosphorus foil, bismuth oxychloride, red 202, red 228, red 226, which may be raked, Yellow No. 4, Blue No. 404, Yellow No. 5, Red No. 505, Red No. 230, Red No. 223, Orange No. 201, Red No. 213, Yellow No. 204, Yellow No. 203, Blue No. 1, Green No. 201, Purple 201 No., red No. 204, etc.
Examples of organic powders include polyethylene powder, polymethyl methacrylate, nylon powder, and organopolysiloxane elastomer.

Examples of the UV absorbers include paraaminobenzoic acid UV absorbers, anthranilic acid UV absorbers, salicylic acid UV absorbers, cinnamic acid UV absorbers, benzophenone UV absorbers, sugar UV absorbers, 2- (2′-hydroxy-5′-t-octylphenyl) benzotriazole, 4-methoxy-4′-t-butyldibenzoylmethane and the like,
Examples of lower alcohols include ethanol, isopropanol, phenoxyethanol, and the like.
Examples of vitamins include vitamin A or derivatives thereof, vitamin B6 hydrochloride, vitamin B6 tripalmitate, vitamin B6 dioctanoate, vitamin B2 or derivatives thereof, vitamin B such as vitamin B12, vitamin B15 or derivatives thereof, α-tocopherol, etc. Preferred examples include vitamin E such as β-tocopherol, γ-tocopherol and vitamin E acetate, vitamin D, vitamin H, pantothenic acid, pantethine, pyrroloquinoline quinone and the like.
Examples of the polymer having a bio-similar structure include polymethacryloyl lysine and polyglycosyl ethyl methacrylate.

In the present invention, the content of oils such as oils / waxes, hydrocarbons, higher fatty acids, higher alcohols, synthetic ester oils and silicone oils is preferably 10% by mass or less, more preferably 5%. % By mass or less, more preferably 2.5% by mass or less, further preferably 2% by mass or less, more preferably 1% by mass or less, and further preferably 0.5% by mass or less.
Moreover, in preferable embodiment of this invention, an oil agent is not contained.
Although the film having the sea-island structure of the present invention is mainly composed of an aqueous component, it can exhibit a feeling of use like milk containing an oil agent.
Therefore, the film having the sea-island structure of the present invention can be in an oil-free form.

In the present invention, the content of the surfactant is preferably 10% by mass or less, more preferably 5% by mass or less, further preferably 2.5% by mass or less, further preferably 2% by mass or less, and further preferably. Is 1% by mass or less, more preferably 0.5% by mass or less.
Moreover, in preferable embodiment of this invention, surfactant is not contained.
The coating film of the present invention can form a stable sea-island structure without containing a surfactant.
Therefore, the coating film having the sea-island structure of the present invention can be in a surfactant-free form.

<2> Composition for forming a film The present invention also relates to a composition capable of forming on the skin a film having the above-described sea-island structure of the present invention by applying to the skin.
The composition of the present invention contains the above-mentioned amphiphilic copolymer and water-soluble polymer and / or salt thereof, and water.
When applied to the skin, the water in the composition evaporates, causing phase separation between the amphiphilic copolymer and the water-soluble polymer. As a result of this phase separation, the coating of the present invention is formed on the skin. In addition, after phase separation, water and polyol in the composition are taken into the aqueous gel formed by the water-soluble polymer.
Hereinafter, the composition of the present invention will be described in more detail. In addition, about the composition of this invention, the matter regarding the film of this invention described in the item of said <1> is applicable.

In the composition of the present invention, the content of the amphiphilic copolymer is preferably 0.01 to 10% by mass, more preferably 0.05 to 7% by mass, still more preferably 0.1 to 5% by mass, and still more preferably. Is 0.5-3 mass%.
According to the composition of the present invention in which the content of the amphiphilic copolymer is in the above range, a film having excellent elasticity and little stickiness can be formed on the skin.

In the present invention, the proportion of the water-soluble polymer in the entire composition is preferably 0.001 to 10% by mass, more preferably 0.005 to 5% by mass, and still more preferably 0.01 to 1% by mass. More preferably, it is 0.05 to 0.5% by mass.
According to the composition of the present invention in which the content of the water-soluble polymer is in the above range, a film excellent in moisture retention and flexibility can be formed on the skin.

In a preferred embodiment of the present invention, the mass ratio of the content of the water-soluble polymer and the amphiphilic copolymer is preferably 1: 100 to 1: 2, more preferably 1:50 to 1: 5, and even more preferably. The ratio is 1:30 to 1:10, more preferably 1:25 to 1:15.
According to the composition of the present invention in which the mass ratio of the content of the water-soluble polymer and the amphiphilic copolymer is in the above range, a highly uniform film can be formed.

In the present invention, it is preferable to include a polyol that promotes / suppresses the separation of the sea phase and the island phase.
That is, in a preferred embodiment of the present invention, the phase separation between the aqueous gel and the amphiphilic copolymer (hereinafter also referred to as an accelerating polyol) and / or the phase separation between the aqueous gel and the amphiphilic copolymer is suppressed. A polyol (hereinafter referred to as an inhibitory polyol) is included. Moreover, it is particularly preferable that both an accelerating polyol and an inhibitory polyol are included.
According to the composition of the present invention containing such a polyol, a film having a highly uniform sea-island structure can be formed on the skin.

As the accelerating polyol, a polyol that raises the cloud point of the aqueous solution by mixing with an aqueous solution of a nonionic surfactant having a polyether chain in the hydrophilic portion can be preferably exemplified. Preferred examples of such an accelerating polyol include 1,3-butylene glycol and polyethylene glycol.
By using such a polyol, it becomes possible to form a film with higher uniformity.

In the present invention, the content of the accelerating polyol in the entire composition of the present invention is preferably 0.1 to 30% by mass, more preferably 1 to 25% by mass, still more preferably 3 to 20% by mass, and still more preferably. Is 5 to 15% by mass.
By setting the content of the accelerating polyol in the entire composition of the present invention within the above range, the uniformity of the film to be formed can be further improved.

Preferred examples of the inhibitory polyol include a polyol that lowers the cloud point of the aqueous solution by mixing it with an aqueous solution of a nonionic surfactant having a polyether chain in the hydrophilic portion. Preferred examples of such inhibitory polyols include glycerin, diglycerin, sorbitol and maltitol.
By using such a polyol, it becomes possible to form a film with higher uniformity.

The content of the inhibitory polyol in the entire composition of the present invention is preferably 0.5 to 30% by mass, more preferably 1 to 25% by mass, further preferably 5 to 20% by mass, and further preferably 8 to 15% by mass. %.
By setting the content of the accelerating polyol in the above range, the uniformity of the film to be formed can be further improved.

In the present invention, the cloud point refers to a temperature at which phase separation occurs due to a temperature change in a transparent or translucent liquid, resulting in opaqueness, and in particular, an aqueous solution of a nonionic surfactant is heated. The temperature at which the solute begins to separate from the water.
Whether the cloud point of an aqueous solution of a nonionic surfactant having a polyether chain in the hydrophilic part is raised or lowered can be specifically confirmed by the following method.
An aqueous solution of a nonionic surfactant having a polyether chain in the hydrophilic portion is heated, and a temperature at which the aqueous solution starts to become cloudy, that is, a cloud point is recorded. Next, the polyol is added to the aqueous solution and mixed, and the cloud point is recorded in the same manner.
When the aqueous solution after the addition has a higher cloud point than the aqueous solution before the addition of the polyol, the added polyol is evaluated as “raised the cloud point of the aqueous solution”.
On the other hand, when the added aqueous solution has a lower cloud point than the aqueous solution before adding the polyol, the added polyol is evaluated as “lowered the cloud point of the aqueous solution”.

As the nonionic surfactant having a polyether chain in the hydrophilic portion used for the above-described cloud point measurement, a nonionic surfactant having polyethylene glycol in the hydrophilic portion can be preferably exemplified.
Specific examples of such nonionic surfactants include polyoxyethylene nayl ether (POE (n) OE, n = 3, 10, 15, 20, 23) (manufactured by Nippon Emulsion Co., Ltd.), POE ( 20) Sorbitan monostearate (manufactured by Toho Chemical Co., Ltd.), POE (20) glycerin monostearate (manufactured by Riken Vitamin Co., Ltd.), POE (10) monostearate (manufactured by Nikko Chemicals Co., Ltd.), polyglycerin (6) Monolaurate (manufactured by Sakamoto Pharmaceutical Co., Ltd.) can be exemplified.

In the present invention, the mass ratio of the accelerating polyol and the inhibiting polyol is preferably 10: 1 to 1:10, more preferably 6: 1 to 1: 5, further preferably 4: 1 to 1: 3, Preferably it is 3.5: 1 to 1: 2.5, more preferably 1.6: 1 to 1: 1.
By setting the mass ratio of the accelerating polyol and the inhibiting polyol within the above range, it is possible to provide a composition capable of forming a film having a highly stable sea-island structure.

In the present invention, the ratio of the total mass of the accelerating polyol and the inhibitory polyol and the mass content of the amphiphilic copolymer is 5: 1 to 20: 1, more preferably 7: 1 to 15: 1, still more preferably 8: 1 to 12: 1.
By setting the ratio of the total mass of the accelerating polyol and the inhibitory polyol and the mass of the amphiphilic copolymer within the above range, a composition having a highly stable sea-island structure can be provided.

In the present invention, the ratio of the total mass of the accelerating polyol and the inhibitory polyol and the total mass of the amphiphilic copolymer and the water-soluble polymer is 5: 1 to 20: 1, more preferably 7: 1 to 15: 1, more preferably 8: 1 to 12: 1.
By setting the ratio of the total mass of the accelerating polyol and the inhibitory polyol and the mass of the amphiphilic copolymer within the above range, a composition having a highly stable sea-island structure can be provided.

In a preferred embodiment of the present invention, the content of the accelerating polyol in the total amount of the three components of the accelerating polyol, the inhibiting polyol and the amphiphilic copolymer is preferably 10 to 80% by mass, more preferably 20 to 70% by mass. %, More preferably 30 to 70% by mass, still more preferably 40 to 60% by mass, and still more preferably 40 to 55% by mass.
By setting the content of the accelerating polyol in the above range, precipitation can be prevented from occurring in the composition, and the stability of the composition can be improved. Moreover, the composition of such a form can form a film excellent in moisture retention and flexibility.

In a preferred embodiment of the present invention, the content of the inhibitory polyol in the total amount of the three components of the accelerator polyol, the inhibitory polyol and the amphiphilic copolymer is preferably 10 to 80% by mass, more preferably 20 to 20%. It is 70% by mass, more preferably 30 to 60% by mass, still more preferably 35 to 50% by mass.
By making content of inhibitory polyol into the said range, it can prevent that precipitation arises in a composition and can improve the stability of a composition. Moreover, the composition of such a form can form a film excellent in moisture retention and flexibility.

In a preferred embodiment of the present invention, the content of the amphiphilic copolymer in the total amount of the three components of the accelerating polyol, the inhibiting polyol and the amphiphilic copolymer is preferably 1 to 50% by mass, more preferably 3%. -20% by mass, more preferably 5-15% by mass, and still more preferably 8-12% by mass.
By setting the content of the amphiphilic copolymer in the above range, a composition having a viscosity that can be easily applied to the skin can be provided. Moreover, the composition of such a form can form a film excellent in moisture retention and flexibility.

In a preferred embodiment of the present invention, the content of the accelerating polyol is 20 to 70% by mass in the total amount of the three components of the accelerating polyol, the inhibitory polyol and the amphiphilic copolymer, and the content of the inhibitory polyol is 20 to 20%. 70% by mass and the content of the amphiphilic copolymer is 5 to 20% by mass.
By setting it as such embodiment, stability of a composition can be improved.

Further, by adjusting the content of the accelerating polyol, the content of the inhibitory polyol, and the content of the amphiphilic copolymer in the total amount of the three components of the accelerating polyol, the inhibitory polyol, and the amphiphilic copolymer to the above ranges, It becomes possible to adjust the major axis / minor axis ratio and the average particle size of the island particles in the coating formed by the composition of the present invention to the preferred ranges described in the above item <1-3>.

The composition of the present invention can be produced by stirring and mixing raw materials at room temperature.

The content of water in the composition of the present invention is preferably 60 to 99% by mass, more preferably 70 to 95% by mass, and still more preferably 80 to 90% by mass.
By applying the composition of the present invention having a water content in the above range to the skin, the film of the present invention can be easily formed on the skin.

<3> Method for Forming Film on Skin The present invention also relates to a method for forming the film of the present invention on the skin.
The method of the present invention is characterized by applying the composition of the present invention to the skin. When the water in the composition evaporates by application, phase separation occurs between the aqueous gel formed by the water-soluble polymer and the amphiphilic copolymer. As a result of this phase separation, a film having the sea-island structure of the present invention can be formed on the skin.

In the present invention, it is preferable to use an aqueous solution containing a polyol that promotes phase separation between the amphiphilic copolymer and the aqueous gel and / or a polyol that suppresses phase separation between the aqueous gel and the amphiphilic copolymer.
By using such an aqueous solution, a film having excellent uniformity can be formed on the skin.

In the composition of the present invention, the content of oils such as oils / waxes, hydrocarbons, higher fatty acids, higher alcohols, synthetic ester oils, silicone oils, etc. is preferably 2% by mass or less. More preferably, it is 1 mass% or less, More preferably, it is 0.5 mass% or less.
Moreover, in preferable embodiment of this invention, an oil agent is not contained.

Moreover, in the composition of this invention, content of surfactant becomes like this. Preferably it is 2 mass% or less, More preferably, it is 1 mass% or less, More preferably, you may be 0.5 mass% or less.
Moreover, in preferable embodiment of this invention, surfactant is not contained.

Preferred forms of the composition and the coating in the method of the present invention are as described in the above items <1> and <2>.

<1> Synthesis of Hydrophobic Monomer Hereinafter, production examples of the hydrophobic monomer represented by the general formula (1) will be shown.
(Production Example 1) Synthesis of glycerin monoacrylate In a 3 L four-necked flask, R)-(+)-2,2-dimethyl-1,3-dioxolane-4-methanol (manufactured by Tokyo Chemical Industry Co., Ltd.) 79 0.5 g, methyl acrylate 258.0 g, and tetramethoxy titanium 3.7 g were charged. Then, the reaction liquid was stirred, and a transesterification reaction was performed at 105 to 110 ° C. for 2.5 hours while introducing nitrogen gas into the liquid. After completion of the reaction, ketal acrylate 1 (intermediate 1) was obtained by fractionation by distillation under reduced pressure.

In a 3 L four-necked flask, 90.2 g of water, 28.4 ml of cation exchange resin RCP160M (manufactured by Mitsubishi Chemical), 94.2 g of Intermediate 1 were charged. Then, the reaction solution was stirred, and a ketal deketone reaction was carried out at 24 ° C. for 27 hours while introducing nitrogen gas into the solution. After completion of the reaction, the cation exchange resin was filtered off from the reaction solution, and the filtered reaction solution was washed 6 times with 100 ml of hexane to remove unreacted raw materials, and then 200 ml of ethyl acetate was added to the aqueous layer to obtain a product. Extracted. Then, ethyl acetate and water were distilled off from this ethyl acetate extract under reduced pressure (800 Pa) at 40 ° C. or less to obtain glyceryl monoacrylate.

(Production Example 2) Trimethylolpropane monoacrylate synthesis step (1): In a eggplant-shaped flask equipped with a calcium tube, a condenser tube and a Dean-Stark trap, 145.7 g of trimethylolpropane, 300 ml of acetone, 3 g of p-toluenesulfonic acid monohydrate and 300 mL of petroleum ether were added, and the mixture was heated to reflux in an oil bath set at 50 ° C. After 12 hours, after confirming that water was no longer generated, the reaction mixture was cooled to room temperature. Next, 3 g of sodium acetate was added and the mixture was further stirred for 30 minutes, and then petroleum ether and acetone were distilled off by an evaporator. The obtained crude product was distilled under reduced pressure to obtain ketalized trimethylolpropane (intermediate 2).

Step (2): 104.8 g of Intermediate 2 obtained in Step (1), 258.0 g of methyl acrylate, and 3.7 g of tetramethoxy titanium were charged into a 3 L four-necked flask. Then, the reaction liquid was stirred, and a transesterification reaction was performed at 105 to 110 ° C. for 2.5 hours while introducing nitrogen gas into the liquid. After completion of the reaction, ketalized trimethylolpropane acrylate ester (intermediate 3) was obtained by fractionation by distillation under reduced pressure.

Step (3): In a 3 L four-necked flask, 90.2 g of water, 28.4 ml of cation exchange resin RCP160M (Mitsubishi Chemical), 115.3 g of Intermediate 3 obtained in Step (2) were charged. Then, the reaction solution was stirred, and a ketal deketone reaction was carried out at 24 ° C. for 27 hours while introducing nitrogen gas into the solution. After completion of the reaction, the cation exchange resin was filtered off from the reaction solution, and the filtered reaction solution was washed 6 times with 100 ml of hexane to remove unreacted raw materials, and then 200 ml of ethyl acetate was added to the aqueous layer to obtain a product. Extracted. Then, ethyl acetate and water were distilled off from this ethyl acetate extract under reduced pressure (800 Pa) at 40 ° C. or lower to obtain trimethylolpropane monoacrylate.

(Production Example 3) Synthesis of trimethylolpropane monomethacrylate Trimethylolpropane and methyl acrylate (acrylate) in Production Example 2, the amount of intermediates obtained in step (1), the intermediates obtained in step (2) Trimethylolpropane monomethacrylate was synthesized in the same manner as in Production Example 2 except that the amount was changed as shown in Table 1. Table 1 shows the trivalent alcohol and its charge, the intermediate obtained in step (1) and its charge, the intermediate obtained in process (2) and its charge.

Production Example 4 Production Example 1 of Hydrophobic Monomer Represented by Formula (1)
In a reaction vessel equipped with a stirrer and a condenser tube, 28.4 g of 16-methylheptadecanoic acid (manufactured by Sigma-Aldrich), 35.7 g of thionyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) and 200 ml of benzene were stirred and mixed. . While continuing stirring, refluxing was performed for 4 hours, and then purification by vacuum distillation was performed to obtain 16-methylheptadecanoic acid chloride.

In a reaction vessel equipped with a stirrer, 16.0 g of glyceryl monomethacrylate (“Blemmer GLM” manufactured by NOF Corporation) and 30.0 g of triethylamine were dissolved in 300 ml of tetrahydrofuran. While the resulting solution was ice-cooled and stirred, a solution prepared by dissolving 60.6 g of 16-methylheptadecanoic acid chloride obtained above in 100 ml of tetrahydrofuran was added dropwise over 2 hours. After completion of the dropwise addition, the produced white precipitate was filtered, and tetrahydrofuran and triethylamine were removed from the filtrate using a rotary evaporator to obtain a product. From the NMR measurement, it was confirmed that the obtained compound was a hydrophobic monomer (hydrophobic monomer 1) derived from the essential structural unit of the copolymer of the present invention represented by the following formula (29).

Hydrophobic monomer 1

Formula (29)

Production Example 5 Production Example 2 of Hydrophobic Monomer Represented by General Formula (1)
In a reaction vessel equipped with a stirrer and a condenser tube, 25.6 g of 2-hexyldecanoic acid (manufactured by Sigma-Aldrich), 35.7 g of thionyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.), and 200 ml of benzene were stirred and mixed. Refluxing was performed for 4 hours while continuing stirring, and then purification by vacuum distillation was performed to obtain 2-hexyldecanoic acid chloride.

In a reaction vessel equipped with a stirrer, 16.0 g of glyceryl monomethacrylate (“Blemmer GLM” manufactured by NOF Corporation) and 30.0 g of triethylamine were dissolved in 300 ml of tetrahydrofuran. While the resulting solution was ice-cooled and stirred, a solution prepared by dissolving 55.0 g of 2-hexyldecanoic acid chloride obtained above in 100 ml of tetrahydrofuran was added dropwise over 2 hours. After completion of the dropwise addition, the produced white precipitate was filtered, and tetrahydrofuran and triethylamine were removed from the filtrate using a rotary evaporator to obtain a product. By NMR measurement, it was confirmed that the obtained compound was a hydrophobic monomer (hydrophobic monomer 2) derived from the essential structural unit of the copolymer of the present invention represented by the following formula (30).

Hydrophobic monomer 2

Formula (30)

Production Example 6 Production Example 3 of Hydrophobic Monomer Represented by Formula (1) Part 3
In a reaction vessel equipped with a stirrer and a cooling tube, 28.4 g of 9-methylheptadecanoic acid (manufactured by Sigma-Aldrich), 35.7 g of thionyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) and 200 ml of benzene were stirred and mixed. . While continuing stirring, refluxing was performed for 4 hours, and then purification by vacuum distillation was performed to obtain 9-methylheptadecanoic acid chloride.

In a reaction vessel equipped with a stirrer, 16.0 g of glyceryl monomethacrylate (“Blemmer GLM” manufactured by NOF Corporation) and 30.0 g of triethylamine were dissolved in 300 ml of tetrahydrofuran. While the resulting solution was ice-cooled and stirred, a solution prepared by dissolving 60.6 g of 9-methylheptadecanoic acid chloride obtained above in 100 ml of tetrahydrofuran was added dropwise over 2 hours. After completion of the dropwise addition, the produced white precipitate was filtered, and tetrahydrofuran and triethylamine were removed from the filtrate using a rotary evaporator to obtain a product. NMR measurement confirmed that the obtained compound was a hydrophobic monomer (hydrophobic monomer 3) derived from the essential structural unit of the copolymer of the present invention represented by the following formula (31).

Hydrophobic monomer 3

Formula (31)

<2> Synthesis of copolymer of the present invention (1) Synthesis of copolymer of Example 1 and Comparative Example 1 Hydrophobic monomer 1 (Production Example 4) 24.0 g in a flask equipped with a nitrogen introduction tube, a condenser and a stirrer. , 90.0 g of methoxypolyethylene glycol (23) methacrylate (manufactured by NOF Corporation, trade name “Blemmer PME-1000”), 300 ml of isopropyl alcohol, phosphate buffer solution (pH 6.8) (manufactured by Nacalai Tesque) ) 300 ml was taken and mixed with stirring. While stirring was continued, nitrogen gas substitution was performed for 1 hour. A solution prepared by dissolving 2.0 g of ammonium persulfate in 20 ml of water was added thereto, and further reacted at 65 ° C. for 10 hours while continuing stirring (reacted for 16 hours under the same conditions to synthesize a copolymer of Comparative Example 1). . After completion of the reaction, the pH was adjusted to 7.0 using an aqueous sodium hydroxide solution, and isopropyl alcohol was removed with a rotary evaporator to obtain an aqueous solution of the copolymer of Example 1 (treated under the same conditions as in Comparative Example 1). An aqueous solution of the copolymer was obtained).
It was 61000 when the weight average molecular weight (polystyrene conversion) of the copolymer of Example 1 was calculated | required by GPC. Moreover, when measured by NMR, mass ratio of a structural unit (a) and a structural unit (b) was about 3: 7.
On the other hand, the copolymer of Comparative Example 1 had a weight average molecular weight of 122500, and the mass ratio of the structural unit (a) to the structural unit (b) was about 3: 7.

(2) Synthesis of copolymers of Examples 2 to 8 By the same method as in (1) above, a copolymer having the structure, weight average molecular weight, and molar ratio of structural unit (a) to structural unit (b) shown in Table 2 was obtained. Synthesized. The weight average molecular weight of the copolymer was adjusted by changing the reaction time. Moreover, the molar ratio of the structural unit (a) and the structural unit (b) can be adjusted by adjusting the molar ratio of the charged amount of the hydrophobic monomer and the hydrophilic monomer added to the reaction solution.
Examples 2 to 6 are copolymers synthesized using the hydrophobic monomer 1. Example 7 is a copolymer synthesized using hydrophobic monomer 2, and Example 8 is a copolymer synthesized using hydrophobic monomer 3.

<Test Example 1>
2% by weight aqueous solutions of the copolymers of Examples 1-6 and Comparative Example 1 were prepared. Each copolymer aqueous solution was applied to the skin of three professional sensory evaluators, and the elasticity was evaluated according to the following criteria. The results are shown in Table 3.
・ A feeling of elasticity ◎ ・・・ There is a very strong feeling of elasticity ○ ・・・ There is a feeling of strong elasticity △ ... There is a feeling of elasticity × ... There is not much elasticity

As shown in Table 3, when the copolymers of Examples 1 to 6 and Comparative Example 1 having the same structure of the structural unit (a) are compared, the aqueous copolymer solution of Examples 1 to 6 is the same as the aqueous copolymer solution of Comparative Example 1. Compared with a strong feeling of elasticity. In particular, the inventive copolymers of Examples 1, 5 and 6 have a very strong feeling of elasticity.
The above results indicate that the copolymer containing the structural unit (a) and the structural unit (b) having a weight average molecular weight of 20000 to 110000, particularly preferably 57000 to 66000 is excellent in elasticity.

<Test Example 2>
In the same manner as in Test Example 1, the feeling of elasticity was also evaluated for the copolymers of Examples 7 and 8. As a result, it was found that the copolymers of Examples 7 and 8 also had a feeling of elasticity.
This result shows that even if the structure of the structural unit (a) is variously changed, a copolymer having a feeling of elasticity can be obtained.

<Test Example 3>
A gel cosmetic was prepared by adding 0.5% by mass of xanthan gum to a 2% by mass aqueous solution of the copolymer of Example 1 or the copolymer of Comparative Example 1. This gel cosmetic was applied to the skin of three professional sensory evaluators as in Test Example 1, and evaluated for non-stickiness, elasticity, and moist feeling. The evaluation was performed according to the following evaluation criteria based on the feeling of use when an emulsion (standard cosmetic) containing trimethylolpropane triisostearate was applied to the skin. Table 4 and FIG. 1 show average values of evaluation values by three evaluators.
・ Evaluation criteria: 4 points… 3 points that are superior to the feel of the reference cosmetics… 2 points of the same feeling as the reference cosmetics: 1 point that is close to the touch of the reference cosmetics but slightly inferior・ 0 points inferior to the feel of the standard cosmetics ... considerably inferior to the feel of the standard cosmetics

As shown in Table 4 and FIG. 1, the gel cosmetic of Example 1 was significantly more elastic than the gel cosmetic of Comparative Example 1, and was excellent in non-stickiness and moist feeling. .
This result shows that the copolymer containing the structural unit (a) and the structural unit (b) having a weight average molecular weight of 20000 to 110000 is excellent in non-stickiness and moist feeling as well as elasticity.

An emulsified composition was produced by stirring and mixing the components shown in Tables 5 to 7 below.
In this example, glyceryl diisostearate methacrylate, which is a hydrophobic monomer, and methoxy methacrylic acid methoxy PEG-23, which is a hydrophilic monomer, are approximately 3: 7 as a water-soluble copolymer that is an emulsifier of the present invention. A (glyceryl diisostearate methacrylate / methoxymethacrylic acid methoxy PEG-23) copolymer having an average molecular weight of 61,000 copolymerized at a mass ratio was used.
Further, polyoxypropylene (polymerization degree 60) and polyoxyethylene (average polymerization degree 11) and PEG / PPG-60 / 11 glycerin (Adecanol M-3228) which is an ether of glycerin are used as the water-soluble copolymer. A product was produced (Comparative Examples 2, 4, 6).
Furthermore, an emulsion composition was produced using polyoxyethylene hydrogenated castor oil as a surfactant (Comparative Examples 3, 5, and 7).

FIG. 2 shows a three-component phase diagram in which the blending ratios of (glyceryl diisostearate methacrylate / methoxy methacrylate PEG-23) copolymer, squalane and water in Examples 9 to 31 are plotted.

FIG. 3 shows a three-component phase diagram in which the blending ratios of (glyceryl diisostearate methacrylate / methoxymethoxymethacrylate methacrylate-23) copolymer, tri (caprylic acid / capric acid) glyceryl and water in Examples 32-62 are plotted. .

FIG. 4 shows a three-component phase diagram in which the blending ratios of (glyceryl diisostearate methacrylate / methoxymethacrylic acid methoxy PEG-23) copolymer, dimethicone and water in Examples 63 to 89 are plotted.

The emulsified compositions of Examples 9 to 89 showed a stable emulsified form even after being stored at room temperature for 3 months. That is, (glyceryl diisostearate methacrylate / methoxy methacrylic acid PEG-23) copolymer allows non-polar hydrocarbon oil squalane, polar hydrocarbon oil tri (caprylic / capric) glyceryl, and silicone Even when any oil agent was used, a stable emulsion composition could be produced.
On the other hand, the compositions of Comparative Examples 2, 4 and 6 containing PEG / PPG-60 / 11 glycerin, which is a water-soluble copolymer, cannot be emulsified even if they are stirred and mixed. Completely separated.
This result shows that according to the water-soluble copolymer which is the emulsifier of the present invention, a stable emulsion composition can be produced using various oil agents.

Further, as shown in Tables 5 to 7, the emulsified composition was prepared in any formulation having a content of (glyceryl diisostearate methacrylate / methoxy methacrylic acid PEG-23) copolymer of 1 to 30% by mass. Could be manufactured.
Further, as shown in Tables 5 to 7, an emulsified composition could be produced even when the oil phase content was 10 to 70% by mass.

Appropriate amounts of Examples 9 to 89 and Comparative Examples 3, 5, and 7 were applied to the skin. As a result, the emulsified compositions of Examples 9 to 89 had no irritation and less stickiness compared to the emulsified compositions of Comparative Examples 3, 5, and 7.
This result shows that the emulsified composition emulsified with the water-soluble copolymer which is the emulsifier of the present invention is superior in usability compared with a general emulsified composition emulsified with a surfactant.

In particular, the emulsified composition of the example in which the content of the (glyceryl diisostearate methacrylate / methoxymethoxy methacrylate-23) copolymer is 15% by mass, more preferably 1% by mass, has a better feeling of use. It was.

<Production Example 7>
The face wash of Examples 90 to 92 and Comparative Examples 8 and 9 were produced according to the formulation shown below. That is, each of the components (a) and (b) was heated to 80 ° C., and (b) was added to the mixture under stirring and stirred, followed by cooling to obtain a face wash.
As the water-soluble copolymer, glyceryl diisostearate methacrylate, which is a hydrophobic monomer, and methoxy PEG-methacrylate methacrylate, which is a hydrophilic monomer, are copolymerized at a molar ratio of approximately 3: 7, and an average molecular weight of 61000. (Glyceryl diisostearate methacrylate / methoxy methacrylic acid PEG-23) copolymer was used.

<Test Example 4>
A skilled evaluator was allowed to wash the face using the face wash of Examples 90 to 92 and Comparative Examples 8 and 9, foaming and foam quality at the time of use, lack of skin feeling after washing and slimy feeling Was evaluated according to the following evaluation criteria. The results are shown in Table 8.
・ Bubbling ◎ ... Bubbling very well ○ ... Bubbling well △ ... Bubbling is weak × ... No bubbling
・ Foam quality ◎ ... Very creamy foam ○ ... Creamy foam quality △ ... Not very creamy × ... Not creamy
・ There is no sense of tension ◎ ・・・ There is no sense of tension ○ ・・・ There is almost no sense of tension △ ・・・ There is a sense of tension × ・・・ There is a strong sense of tension
・ No slimy feeling ◎ ・・・ No slimy feeling ○ ・・・ No slimy feeling △ ・・・ Smooth feeling × ・・・ Strong slimy feeling

As shown in Table 8, the face wash of Comparative Example 8 had a strong feeling on the skin after face washing, while the face wash of Examples 90 to 92 had almost no feeling of tension after face washing.
This result indicates that the (glyceryl diisostearate methacrylate / methoxy methacrylic acid methoxy PEG-23) copolymer has reduced skin firmness caused by fatty acid soaps.

In addition, in the face wash of Comparative Example 9 containing carboxymethylcellulose which is a water-soluble polymer instead of the (glyceryl diisostearate methacrylate / methoxymethoxy PEG-23 methacrylate) copolymer, good foaming which is an advantage of fatty acid soap is obtained. Was not seen. On the other hand, the face washes of Examples 90 to 92 showed good foaming.
As a result, according to the (glyceryl diisostearate methacrylate / methoxymethacrylate PEG-23) copolymer, it is possible to reduce the firmness of the skin after use without inhibiting the good foaming of the fatty acid soap. Show.
Moreover, as shown in Table 8, the face wash of Examples 91 and 92 showed foaming superior to the face wash of Comparative Example 8.
This result indicates that the foaming of the fatty acid soap can be improved by setting the content of the (glyceryl diisostearate methacrylate / methoxymethoxy methacrylate-23) copolymer to 0.8 mass% or more.

Further, as shown in Table 8, the face wash of Comparative Example 9 had a strong slimy feeling on the skin after face washing. On the other hand, the face wash of Examples 90 to 92 had almost no sliminess after the face washes.
This result shows that according to the (glyceryl diisostearate methacrylate / methoxymethacrylate PEG-23) copolymer, it is possible to reduce the firmness of the skin after using the skin cleansing agent without causing a slimy feeling. ing.
Further, as shown in Table 8, the face wash of Examples 90 and 91 is superior to the face wash of Example 92 in that there is no sliminess.
As a result, the content of the (glyceryl diisostearate methacrylate / methoxymethoxymethacrylate methacrylate-23) copolymer is 3% by mass or less, so that the skin becomes firm after use of the skin cleansing agent without causing a slimy feeling. This shows that the feeling can be reduced.

<Production Example 8>
The gel cleansing agents of Examples 93 to 96 and Comparative Examples 10 to 12 were obtained by stirring and mixing the components shown in Table 9.

<Test Example 5>
As in Test Example 4, a skilled evaluator washes the face with a gel cleanser and used the following evaluation criteria to determine the cleansing power, ease of spreading to the skin during use, and lack of skin feeling after washing. (Evaluation criteria for the absence of feeling of tension are the same as in Test Example 4). The results are shown in Table 9.
-Detergency ◎ ... Detergency is very strong ○ ... Detergency is strong △ ... Detergency is weak x ... Detergency is very weak
・ Ease of spreading to the skin ◎ ・・・ Extremely easy to spread ○ ・・・ Easy to spread △ ・・・ Difficult to stretch × ・・・ Very difficult to stretch

As shown in Table 9, the gel cleansers of Comparative Examples 10 and 11 had a strong feeling of firmness on the skin after the face washes, while the face washes of Examples 93 to 96 had almost no sense of tension after the face washes.
This result shows that the (glyceryl diisostearate methacrylate / methoxymethacrylate methacrylate PEG-23) copolymer reduced the feeling of skin firmness caused by the nonionic surfactant.
Moreover, as shown in Table 9, the gel cleanser of Examples 94 and 95 is superior to the gel cleanser of Example 93 in reducing the feeling of skin tightness after use.
This result shows that the content of the (glyceryl diisostearate methacrylate / methoxy methacrylic acid methoxy PEG-23) copolymer is 0.7% by mass or more, thereby reducing the skin feeling after use more effectively. It shows that you can.

Further, as shown in Table 9, the gel cleanser of Examples 93 to 96 is superior in detergency as compared with the gel cleanser of Comparative Examples 10 to 12.
This result indicates that the (glyceryl diisostearate methacrylate / methoxy methacrylic acid methoxy PEG-23) copolymer can improve the detergency of a skin cleanser containing a nonionic surfactant.
Furthermore, the gel cleanser of Example 95 is superior in detergency compared to the gel cleanser of Examples 93 and 94.
As a result, the detergency of the skin cleanser containing the nonionic surfactant is improved by setting the content of the (glyceryl diisostearate methacrylate / methoxy methacrylic acid methoxy PEG-23) copolymer to 2% by mass or more. It shows that you can.

Moreover, as shown in Table 9, the gel cleanser of Example 94 is superior in ease of spreading to the skin as compared with the gel cleanser of Examples 93 and 95.
As a result, the content of the (glyceryl diisostearate methacrylate / methoxy methacrylic acid methoxy PEG-23) copolymer is set to 0.6 to 3% by mass, thereby improving the ease of spreading to the skin when using the gel cleanser. It shows that it can be improved.

Further, the gel cleanser of Example 91 and the gel cleanser of Example 93 have the same nonionic surfactant content, but are of different types. However, as shown in Table 9, these two types of gel face wash showed the same effect in terms of detergency, ease of spreading on the skin, and no feeling of tension.
This result shows that the advantageous effect of including the (glyceryl diisostearate methacrylate / methoxymethoxy methacrylate-23) copolymer in the skin cleanser does not depend on the type of surfactant contained in the skin cleanser. Show.

The results of Test Examples 4 and 5 indicate that according to the present invention, it is possible to reduce the firmness of the skin after using the skin cleanser.
In addition, according to the present invention, after use while improving or improving the advantageous effects inherent to the skin cleanser such as good foaming, creamy foam quality, detergency, and ease of spreading to the skin. It shows that the feeling of tightness of the skin can be reduced.

<Production Example 9>
According to the formulation shown in Table 10, oil-in-water sunscreen cosmetics of Examples 98 to 103 and Comparative Examples 13 to 15 were produced by the following method.
(A) was mixed and dissolved by heating to prepare a mixture of oil phase components, and dispersed with hydrophobized fine particles of titanium oxide using a disper.
Next, (A) was added to the heated (I) and emulsified with a homogenizer. After emulsification, sunscreen cosmetics were produced by adding (c) and (d) and cooling with stirring and mixing.
In this example, as the water-soluble copolymer of component (A), glyceryl diisostearate methacrylate, which is a hydrophobic monomer, and methoxy methacrylic acid methacrylate PEG-23, which is a hydrophilic monomer, are added at a molar ratio of about 3: 7. A copolymer of (glyceryl diisostearate methacrylate / methoxy methacrylic acid PEG-23) copolymer having an average molecular weight of 61000 was used.

<Test Example 6>
The oil-in-water type sunscreen cosmetics of Examples 97 to 102 and Comparative Examples 13 to 15 thus prepared were evaluated according to the following criteria for emulsification stability, no stickiness when used, and moisturizing feeling. The results are shown in Table 10.

・ Emulsion stability (when stored at room temperature for 1 month)
A: No separation of the oil phase is observed at all O: A separation of the oil phase is hardly observed.
Δ: An oil film is exposed on the surface of the preparation. X: Separation of the oil phase is clearly observed.

・ No stickiness ◎ ・・・ No stickiness sensation ○ ・・・ Almost no stickiness △ ・・・ There is a sticky feeling × ・・・ Such stickiness
・ Moisturizing feeling ◎ ・・・ Moist feeling is very strong ○ ・・・ Moist feeling is strong △ ・・・ Moist feeling is weak × ・・・ Moist feeling is very weak

As shown in Table 10, the oil-in-water sunscreen cosmetics of Examples 97 to 102 containing all the components (A) to (D) have good emulsification stability, no stickiness, and moisturizing feeling. Had.
On the other hand, the sunscreen cosmetic of Comparative Example 13 that does not contain the component (A) was quite sticky. Moreover, the sunscreen cosmetics of the comparative example 14 which does not contain a component (B), and the sunscreen cosmetics of the comparative example 15 which does not contain a component (C) were inferior in emulsion stability.
These results indicate that the oil-in-water sunscreen cosmetics containing the components (A) to (D) have excellent emulsification stability, no stickiness, and a moisturizing feeling.

Moreover, as shown in Table 10, the sunscreen cosmetic of Example 97 containing sodium stearyl lactate as the component (C) is compared with the sunscreen cosmetic of Example 100 containing sodium cocoglyceryl sulfate as the component (C). And excellent in emulsion stability.
This result has shown that the oil-in-water type sunscreen cosmetics which contain sodium acyl lactate as a component (C) are excellent in emulsification stability.

In addition, as shown in Table 10, the sunscreen cosmetic of Example 97 containing polyglycerin-10 pentastearate as the component (B) has the composition of Example 101 containing polyglyceryl tristearate as the component (B). Emulsification stability is superior compared to sunscreen cosmetics.
This result shows that the oil-in-water sunscreen cosmetic containing polyglycerin-10 pentastearate as the component (B) is excellent in emulsion stability.

Further, as shown in Table 10, the sunscreen cosmetics of Example 97 containing sodium polyacrylate-coated fine particle titanium dioxide as the ultraviolet scattering agent of component (D) are those of Example 102 not containing the coated fine particle titanium dioxide. Excellent moisturizing feeling compared to sunscreen cosmetics.
As a result, an oil-in-water sunscreen cosmetic containing an ultraviolet scattering agent surface-treated with sodium polyacrylate as the component (D), that is, a water-dispersible ultraviolet scattering agent, has an excellent moisturizing feeling. It is shown that.

Further, the sunscreen cosmetic of Example 102 is more stable in emulsification than the sunscreen cosmetics of Example 98 and Example 99, in which the content of component (B) is 0.3% by mass and 7% by mass, respectively. It is excellent in the property and the absence of stickiness.
As a result, the content of the component (B) is preferably 0.5% by mass or more from the viewpoint of improving the emulsion stability, and is preferably 5% by mass or less from the viewpoint of suppressing stickiness. It is shown that.

Moreover, the sunscreen cosmetics of Example 97 are compared with the sunscreen cosmetics of Example 98 and Example 99 in which the content of the component (C) is 0.05% by mass and 1.5% by mass, respectively. Excellent emulsification stability and no stickiness.
As a result, the content of the component (C) is preferably 0.07% by mass or more from the viewpoint of improving the emulsion stability, and is preferably 1% by mass or less from the viewpoint of suppressing stickiness. It is shown that.

<Production Example 10>
As shown in Table 11, the contents of xanthan gum and amphiphilic copolymer were fixed, and the contents of 1,3-butylene glycol (promoting polyol) and glycerin (inhibiting polyol) were variously changed. 103-123 compositions of the present invention were prepared. The contents of 1,3-butylene glycol and glycerin in each example were adjusted as represented by the three-component phase diagram shown in FIG. 5 in relation to the total amount of xanthan gum and amphiphilic copolymer.
As the amphiphilic copolymer, an average molecular weight obtained by copolymerizing glyceryl diisostearate methacrylate, which is a hydrophobic monomer, and methoxy PEG-23 methacrylate, which is a hydrophilic monomer, at a molar ratio of approximately 3: 7. 61,000 (glyceryl diisostearate methacrylate / methoxy methacrylic acid PEG-23) copolymer was used.
In the following test examples, a fluorescent probe “NBD-COCl” was chemically introduced to facilitate observation of the sea-island structure with a microscope (glyceryl diisostearate methacrylate / methoxy methacrylic acid PEG-23). A composition was prepared using the copolymer.

<Test Example 7> Observation of the sea-island structure of the coating About 0.5 g of the composition of Examples 103 to 123 was applied to a range of about 1.5 cm × 1.5 cm on a slide glass and left at 40 ° C. for 3 days. A film was formed on the slide glass by evaporating the water in the composition. The structures of the coatings of Examples 103 to 123 thus formed were observed with a confocal laser scanning microscope.
As a result, each composition formed a sea-island structure. FIG. 6 shows micrographs of the compositions of Examples 105, 106, 108, 111, 113, 114, 115, 119, 120, 122, and 123.

As shown in FIG. 6, in the compositions of Examples 115, 119, and 120, island particles are aggregated, and the island particles having an average particle diameter of more than 10 μm or the major axis / minor axis ratio of less than 0.5 are used. Many particles were observed.
On the other hand, in the compositions of Examples 106 to 114, no aggregation of island particles was observed, and the number particle size distribution of fine island particles having an average particle diameter of 1 to 5 μm was 80% or more.
This result shows that the composition in which the total amount of the water-soluble polymer and the amphiphilic copolymer in the total amount of the components shown in the three-component phase diagram of FIG. 5 is 15% by mass or less hardly causes the aggregation of the island particles. Show.

Further, the area ratio of the sea phase to the island phase in the coatings of Examples 103 to 114 in which no aggregation of island particles was observed and the number particle size distribution of fine island particles having an average particle diameter of 1 to 5 μm was 80% or more. Was 6: 4 to 7: 3.

<Test Example 8> Sensory evaluation For the film formed on the skin after the composition of Example 103 was used by 48 evaluators and applied to the skin, a moist feeling, a feeling of elasticity, a soft feeling, a soft feeling, a plump The feeling and stickiness were evaluated on a 7-point scale as shown in FIG. In addition, commercially available lotions and emulsions were used for comparison. The results are shown in FIG.
In addition, as a lotion, the general thing containing water mainly and containing a polyol, a known water-soluble polymer, antiseptic | preservative, and extracts was used. As the emulsion, an oil-in-water emulsified cosmetic containing mineral oil, macadamia nut oil and the like as an oil phase component was used.

As shown in FIG. 7, for the film formed after applying the composition of Example 103 to the skin, is the moist feeling, elasticity, softness, sticky feeling, and fluffy feeling equivalent to the emulsion containing oil? Higher evaluation was obtained.
Moreover, as shown in FIG. 7, the coating film formed by the composition of Example 103 had a remarkably low stickiness as compared with the emulsion, and was similar to the lotion.

This result shows that, although the composition of the present invention is mainly composed of an aqueous component, a film having a milk-like feel can be formed on the skin. In particular, the composition of the present invention shows that it is possible to achieve both moisture retention and flexibility, which is difficult to achieve with cosmetics mainly composed of water-soluble ingredients.
Further, this result shows that since the composition of the present invention is mainly composed of an aqueous component, there are few disadvantages such as stickiness seen in cosmetics containing an oil agent.

<Production Example 11>
The inventive compositions of Examples 124 and 125 were prepared according to the formulation in Table 12.

The coating film formed by the compositions of Examples 124 and 125 was observed with a microscope in the same manner as in Test Example 8. As a result, as in the coating films of Examples 103 to 114, no aggregation of island particles was observed, and the number particle size distribution of fine island particles having an average particle diameter of 1 to 5 μm was 80% or more.
This result shows that even when polyquaternium-61 and (glyceryl amidoethyl methacrylate / stearyl methacrylate) copolymer are used as the amphiphilic copolymer, a film having a good sea-island structure can be formed. Yes. That is, even when various types of amphiphilic copolymers having a structural unit derived from a hydrophobic monomer and a structural unit derived from a hydrophilic monomer are changed, by combining the water-soluble polymer and water, This shows that a composition capable of forming a film having a sea-island structure can be prepared.

The copolymer of the present invention that solves the first problem can be applied to cosmetics.

The present invention for solving the second problem can be applied to emulsified cosmetics.

The present invention that solves the third and fourth problems can be applied to a facial cleanser.

The present invention that solves the fifth problem can be applied to sunscreen cosmetics.

The present invention that solves the sixth problem can be applied to oil-free cosmetics.

1 Example 103
2 Example 104
3 Example 105
4 Example 106
5 Example 107
6 Example 108
7 Example 109
8 Example 110
9 Example 111
10 Example 112
11 Example 113
12 Example 114
13 Example 115
14 Example 116
15 Example 117
16 Example 118
17 Example 119
18 Example 120
19 Example 121
20 Example 122
21 Example 123

Claims

One or two or more structural units (a) derived from a hydrophobic monomer represented by the following general formula (1) and one or two structural units derived from a hydrophilic monomer represented by the following general formula (2) A copolymer having a weight average molecular weight of 20,000 to 110,000, comprising at least a constituent unit (b) as an essential constituent unit.
General formula (1)

(1)
(In the general formula (1), R1 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R2 and R3 may be the same or different, have no ring structure, have a branched structure and have 6 to 22 carbon atoms. X represents a group in which an OH group is eliminated from a trivalent alcohol.)
General formula (2)

(2)
(In the general formula (2), R4 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R5 represents an alkylene group having 2 to 4 carbon atoms which may have a hydroxyl group, and R6 represents a hydrogen atom or carbon atom. And represents 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, and n represents an integer of 6 to 40.)
The copolymer according to claim 1, wherein the mass ratio of the structural unit (a) to the structural unit (b) is 25:75 to 35:65.
The copolymer according to claim 1 or 2, wherein the molar ratio of the structural unit (a) to the structural unit (b) is 35:65 to 46:54.
The copolymer according to any one of claims 1 to 3, wherein the hydrophobic monomer is a hydrophobic monomer represented by the following general formula (3).
General formula (3)

(3)
(In the general formula (3), R7 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R8 and R9 may be the same or different, have no ring structure, have a branched structure and have 10 to 22 carbon atoms. Or an acyl group having 6 to 9 carbon atoms and having 2 or more branches that does not contain a ring structure, and Y represents a group in which an OH group is eliminated from a trivalent alcohol.
The polymer according to any one of claims 1 to 4, wherein the hydrophilic monomer is a hydrophilic monomer represented by the following general formula (4).
General formula (4)

(4)
(In the general formula (4), R10 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R11 represents a hydrogen atom, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or an aliphatic hydrocarbon having 1 to 14 carbon atoms. Group or an acyl group having 1 to 12 carbon atoms, m represents an integer of 6 to 40)
The copolymer according to any one of claims 1 to 5, wherein the trihydric alcohol is selected from the group consisting of glycerin, trimethylolpropane, and trimethylolethane.
The copolymer according to any one of claims 1 to 6, wherein the hydrophobic monomer is a compound represented by the following general formula (5).
General formula (5)

(5)
(In general formula (5), R12 and R13 may be the same or different and each represents a branched acyl group having 18 carbon atoms that does not contain a ring structure.)
The polymer according to any one of claims 1 to 7, wherein the hydrophilic monomer is a hydrophilic monomer represented by the following general formula (6).
General formula (6)
(6)
(In general formula (6), l represents an integer of 6 to 40.)
An external preparation for skin containing the copolymer according to any one of claims 1 to 8.