JP2012097160A - Copolymer, and composition for cosmetic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copolymer that exhibits high setting properties and high re-styling properties and yet has a wide degree of freedom for formulations such as a spray, mist, wax and the like, and a composition for a cosmetic that comprises the copolymer.SOLUTION: The copolymer comprises a constituting unit corresponding to a vinyl monomer (A) represented by general formula (1) and a constituting unit corresponding to a vinyl monomer (B) based on [an alkyl (meth)acrylate or an N-alkyl-(meth)acrylamide] represented by a specific formula, does not dissolve in water lower than 30°C and has a heat absorption initiation temperature between -25°C and 40°C when heated from a low temperature. The composition for a cosmetic comprises the copolymer. In general formula (1), Ris a hydrogen atom or a 1-3C alkyl group: Ris a 2-4C alkylene group; Ris a hydrogen atom or a methyl group; and m is an integer of 1-100.

Description

  The present invention relates to a copolymer having a specific structure and a cosmetic composition containing the copolymer.

  In recent years, waxy hair conditioners (hair waxes) have been widely accepted mainly by young people. Conventional hair setting agents such as hair mousse, gel, spray, etc., show that resin forms a film on the hair and expresses setting properties, whereas hair wax mainly consists of carnauba wax, candelilla wax, and microcrystalline wax. With the solid oil component, the hair-styling effect of combining and arranging the hair is realized (for example, Patent Documents 1 and 2).

  In the past, hair wax has been developed for higher hair styling properties (setting power, maintainability, re-hair styling properties) and a good feel to use. For example, high-polymerization polyethylene glycol, wax, hair styling compounded with a nonionic surfactant (Patent Document 3), hair wax compounded with 12-hydroxystearic acid and an alkaline agent (Patent Document 4), etc. are disclosed. Has been.

  On the other hand, it has a structural unit derived from a vinyl monomer having a specific alkylene oxide group as a hydrophilic group and a vinyl monomer having a specific alkyl group as a hydrophobic group, and is dissolved in water and clouded at 30 ° C to 70 ° C. A copolymer having a point is known (Patent Document 5). In this copolymer, it is said that a hydrophobic film can be formed on hair using a hair dryer, and a cosmetic useful for hair styling can be provided.

JP-A-10-45546 JP 2001-316228 A JP 2002-241243 A JP 2000-86450 A JP 2001-316422 A

  However, as described in Patent Documents 3 to 4, when a large amount of a solid component or a resin is blended for high hair styling properties, emulsification becomes difficult and it becomes impossible to formulate, and even if it can be formulated, elongation to the hair is increased. There is a problem that it is bad and feels bad. Furthermore, waxes, which are solid oils derived from natural products, have problems in terms of odor over time and the provision of stable quality, and materials that can replace them are demanded.

In addition, the copolymer as described in Patent Document 5 has a treatment property by forming a hydrophobic film on the hair when using a hair dryer or the like. It is insufficient.
In particular, in applications such as hair wax, it is required to have excellent re-hairing properties such as a soft hair feel and a once-set style in addition to a high setting power.

  An object of the present invention is to solve the above-mentioned problems, and a copolymer having a wide range of formulations such as spray, mist, wax, etc. while having high setting property and re-styling property, and this copolymer. It is an object to provide a cosmetic composition comprising a polymer.

As a result of intensive investigations in view of the above problems, the present inventor is a copolymer comprising a structural unit derived from a vinyl monomer having a specific structure, and does not dissolve in water below 30 ° C., and is heated from a low temperature. In this case, the copolymer having an endothermic start point between −25 ° C. and 40 ° C. has a high setting property and a re-styling property when applied to the hair, and the copolymer is further applied to, for example, water or ethanol. It has been found that a wide variety of preparation forms can be realized as a cosmetic composition by dispersing, and the present invention has been completed.
That is, the gist of the present invention resides in the following [1] to [9].

[1] A copolymer comprising a structural unit corresponding to the vinyl monomer (A) represented by the following general formula (1) and a structural unit corresponding to the vinyl monomer (B) represented by the following general formula (2). A copolymer which is a polymer and does not dissolve in water of less than 30 ° C and has an endothermic start point between -25 ° C and 40 ° C when the temperature is raised from a low temperature.

(In General Formula (1), R ¹ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ² represents an alkylene group having 2 to 4 carbon atoms, and R ³ represents a hydrogen atom or a methyl group. m represents an integer satisfying 1 to 100.)

(In general formula (2), R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents an alkyl group having 2 to 10 carbon atoms, p and q each represents an integer of 0 or 1, and p + q = 1. is there.)

[2] The method according to [1], further comprising a structural unit corresponding to a monomer represented by the following general formula (3) and / or a vinyl monomer (C) which is a monomer represented by the following general formula (4): Copolymer.

(In General Formula (3), R ⁶ represents a hydrogen atom or a methyl group, and R ⁷ and R ⁸ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.)

(In general formula (4), R ⁹ represents a hydrogen atom or a methyl group. R is 0 or 1, s is an integer satisfying 1 to 4. X is the following general formula (5) to (7). Any one of them.)

(In the general formulas (5) to (7), R ¹⁰ and R ¹¹ each independently represent an alkyl group having 1 to 4 carbon atoms, and R ¹² in the general formula (6) represents an alkyl group having 1 to 4 carbon atoms, or ^{_{- (CH 2) u -COO -}} (u is an integer from 1 to 4.) indicates one of and its salts).

[3] The copolymer according to [2], comprising structural units corresponding to each of the vinyl monomers (A) to (C) in the following proportion with respect to the entire copolymer.
Vinyl monomer (A): 30 to 80% by weight
Vinyl monomer (B): 20 to 70% by weight
Vinyl monomer (C): 0.1 to 50% by weight

[4] The copolymer according to any one of [1] to [3], wherein in the general formula (2) representing the vinyl monomer (B), p = 1.

[5] The copolymer according to any one of [1] to [4], further comprising a structural unit corresponding to the vinyl monomer (D) having an alkyl group having 12 to 22 carbon atoms.

[6] The copolymer according to any one of [1] to [5], wherein the weight average molecular weight is 5,000 or more and 2,000,000 or less.

[7] An aqueous dispersion characterized in that fine particles containing the copolymer according to any one of [1] to [6] are dispersed in a continuous phase containing water.

[8] The aqueous dispersion according to [7], wherein the fine particles containing the copolymer according to any one of [1] to [6] are dispersed with a volume average particle diameter of 10 to 500 nm.

[9] A cosmetic composition comprising the copolymer according to any one of [1] to [6].

  ADVANTAGE OF THE INVENTION According to this invention, the copolymer which has the freedom degree of a wide formulation, such as spray, mist, and a wax form, having a high setting property and re-hairing property, and the composition for cosmetics containing this copolymer are provided. Is done.

  Embodiments of the present invention will be described in detail below. However, the description of the constituent elements described below is a representative example of the embodiments of the present invention, and the present invention is not limited to these contents. .

  In this specification, “(meth) acryl” is a general term for “acryl” and “methacryl”. The same applies to “(meth) acrylate” and “(meth) acryloyl”. In the present specification, “to” is used to include numerical values or physical values described before and after.

1. Copolymer The copolymer of the present invention corresponds to a structural unit corresponding to the vinyl monomer (A) represented by the following general formula (1) and a vinyl monomer (B) represented by the following general formula (2). A copolymer comprising structural units (hereinafter simply referred to as “copolymer”). In addition, the copolymer is characterized in that it does not dissolve in water below 30 ° C. and has an endothermic start point between −25 ° C. and 40 ° C. when the temperature is raised from a low temperature.

(In General Formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkylene group having 2 to 4 carbon atoms, and R ³ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. m represents an integer satisfying 1 to 100.)

(In general formula (2), R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents an alkyl group having 2 to 10 carbon atoms, p and q each represents an integer of 0 or 1, and p + q = 1. is there.)

<Non-water solubility>
The copolymer of the present invention does not dissolve in water having a water temperature of less than 30 ° C.
Here, “does not dissolve in water” means that when the dried copolymer is added to water of less than 30 ° C., for example, water of about 10 to 30 ° C. as a solid content so as to be 1% by weight, -Even if stirrer processing is performed, it shows that the sample is in a non-uniform state at a temperature of less than 30 ° C., and specifically there is insoluble matter having a size of 100 μm or more that can be visually confirmed. Alternatively, it means a state in which the volume average particle diameter of the insoluble material is 50 μm or more, preferably 100 μm or more.

  As a copolymer that dissolves in water of less than 30 ° C., the proportion of the structural unit corresponding to the vinyl monomer (A) in the copolymer is too large, or the molecular weight of the copolymer is too small, It is conceivable that the proportion of structural units corresponding to any hydrophilic vinyl monomer in the coalescence is too large.

  When the proportion of the structural unit corresponding to the vinyl monomer (A) in the copolymer is too large, the hair styling property tends to be impaired because the coating film strength of the copolymer is small because there are few hydrophobic portions. In addition, when the molecular weight of the copolymer is too small, the flowability of the copolymer is high, so that the re-styling property tends to be inferior. Furthermore, when the proportion of the structural unit corresponding to any hydrophilic vinyl monomer is too large, the adhesive strength is reduced due to the inhibition of crystallinity of the polyoxyalkylene group, and the coating strength is reduced due to the small number of hydrophobic portions. Both inferiority and re-styling properties are inferior. In any case, the hair styling property and the hair styling maintenance property under high humidity tend to be remarkably lowered.

  In order to obtain a copolymer that does not dissolve in water below 30 ° C., for example, the proportion of the structural unit corresponding to the vinyl monomer (A) in the copolymer is decreased; the degree of polymerization is increased, or a crosslinking agent is added. To increase the molecular weight of the copolymer; to reduce the proportion of structural units corresponding to any hydrophilic vinyl monomer in the copolymer; or to the copolymer on the highly hydrophobic side such as a long chain alkyl group Examples of such means include introducing a structural unit corresponding to a vinyl monomer having a chain. Also, water solubility can be controlled by appropriately combining the above methods.

<Endotherm start point>
The copolymer of the present invention has an endothermic starting point between −25 ° C. and 40 ° C. when the temperature is raised from a low temperature.

  The endothermic starting point of the copolymer is, for example, using a differential scanning calorimeter (DSC), using an aluminum sealed cell, air as a reference, and the copolymer in the cell from the low temperature side at 10 ° C./min. When the temperature is raised at a speed, it refers to the temperature at which the heat flow increases from the baseline, and the endothermic start point is at -25 to 40 ° C. at about room temperature (20 ° C.). Means there is a transition point. Specifically, the endothermic starting point of the copolymer can be evaluated by the method described in the Examples below.

  In the copolymer of the present invention, the structural part derived from the hydrophilic monomer (A) may undergo microphase separation from the structural part derived from the hydrophobic monomer (B). The endothermic behavior described in the present invention is considered to be derived from the crystallinity of the polyoxyalkylene group of the structural unit corresponding to the vinyl monomer (A) phase-separated in the copolymer. In the vicinity of the endothermic start temperature, the crystallinity of the polyoxyalkylene chain is weakened to form a paste, which is considered to exhibit adhesiveness when applied onto the hair and enhance hairstyling.

  On the other hand, the phase mainly composed of the structural unit corresponding to the hydrophobic vinyl monomer (B) connects the hydrophobic portions of the copolymer chain by van der Waals force or hydrophobic bond to suppress the fluidity of the copolymer. ing. As a result, the strength of the copolymer is improved, and the adhesion between the hairs attached by the tackiness of the polyoxyalkylene group can be maintained. From the above, in addition to high setability, re-hair shaping is realized.

  In addition, this hydrophobic part makes the polyoxyalkylene chain less sticky when touched lightly by hand, and can strongly bond the hairs together when pressure is applied between the hairs in a manner such as arranging by hand. .

  When the endothermic start point is −25 ° C. or more and 40 ° C. or less, the copolymer exhibits adhesiveness when applied onto the hair at room temperature (20 ° C.), and has high setting properties when a hair cosmetic containing the copolymer is obtained. Can demonstrate

  The endothermic starting point of the copolymer of the present invention is preferably 35 ° C. or lower, more preferably 30 ° C. or lower, particularly preferably 20 ° C. or lower, more preferably 18 ° C. or lower, while preferably −25 ° C. or higher, More preferably, it is -10 degreeC or more, More preferably, it is 0 degreeC or more.

<Endotherm>
The copolymer of the present invention has an endothermic amount measured in the measurement of the endothermic starting point of 0.5 to 90 mJ / mg, indicating that the structure of the polyoxyalkylene group in the copolymer is sticky. Is preferred because it increases hair and improves hairdressing properties. The endothermic amount is more preferably 1.0 mJ / mg or more, still more preferably 1.5 mJ / mg or more, while more preferably 70 mJ / mg or less, still more preferably 50 mJ / mg or less, particularly preferably 35 mJ / mg. It is as follows. The endothermic amount of the copolymer can be adjusted by appropriately selecting a highly hydrophobic vinyl monomer as a monomer for forming the copolymer and introducing a highly hydrophobic structure into the copolymer.

<Molecular weight>
The weight average molecular weight of the copolymer of the present invention is preferably 5,000 or more, more preferably 10,000 or more, preferably 2,000,000 or less, more preferably 1,000,000 or less, and further Dispersibility of the copolymer in water when it is used as a cosmetic composition when the weight average molecular weight of the copolymer is preferably 500,000 or less, particularly preferably 300,000 or less, is not more than the above upper limit. In view of the above, it is preferable from the viewpoint of making the copolymer insoluble in water that it is not less than the above lower limit.
The weight average molecular weight of the copolymer can be measured by various conventionally known methods such as gel permeation chromatography (for example, using tetrahydrofuran as a developing solvent) and a light scattering method.

  The molecular weight distribution [Mw / Mn] represented by the weight average molecular weight / number average molecular weight of the copolymer of the present invention is usually 1.0 or more, preferably 1.5 or more, preferably 5.0 or less, More preferably, it is 3.0 or less, More preferably, it is 2.5 or less.

<Constituent units constituting the copolymer>
Hereinafter, the structural unit which comprises the copolymer of this invention is explained in full detail.
The copolymer of the present invention comprises a vinyl monomer having a polyoxyalkylene group (vinyl monomer represented by the general formula (1)), an alkyl (meth) acrylate monomer and / or (meth) acrylamide (general formula (2)). And a copolymer corresponding to a copolymer of a monomer mixture containing a vinyl monomer). That is, a copolymer comprising a structural unit corresponding to the vinyl monomer (A) represented by the general formula (1) and a structural unit corresponding to the vinyl monomer (B) represented by the general formula (2). It is.

  Here, the copolymer of the present invention is obtained by copolymerizing a monomer mixture containing the vinyl monomer (A) represented by the general formula (1) and the vinyl monomer (B) represented by the general formula (2). It is not restricted to the obtained copolymer, The raw material and manufacturing method will not be restrict | limited if it has a structural unit corresponding to this.

<Constitutional unit corresponding to vinyl monomer (A)>
The vinyl monomer (A) represented by the general formula (1) (hereinafter sometimes referred to as “monomer (A)”) is not particularly limited as long as it is a monomer represented by the following general formula (1). .

(In General Formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkylene group having 2 to 4 carbon atoms, and R ³ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. m represents an integer satisfying 1 to 100.)

R ¹ in the general formula (1) is a hydrogen atom or a methyl group.

R ² in the general formula (1) is an alkylene group having 2 to 4 carbon atoms, preferably an ethylene group or a propylene group. Incidentally, a plurality of R ² may in each molecule, but may be different even in the same, preferably identical.

R ³ in the general formula (1) is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, preferably a hydrogen atom or a methyl group.

  M in General formula (1) is an integer of 1-100. Since the hydrophilicity of the copolymer is ensured and sufficient crystallinity is obtained, m is 1 or more, preferably 3 or more, more preferably 11 or more, and particularly preferably 15 or more. On the other hand, m is 100 or less, and preferably 50 or less, because the residual amount of monomer after the polymerization reaction is small and it is easy to obtain an industrial grade.

  Specific examples of the monomer (A) include methoxypolyoxyethylene (meth) acrylate, polyoxyethylene (meth) acrylate, and methoxypolyoxyethylene / polyoxypropylene (meth) acrylate. Among these, for reasons of hydrophilicity and crystallinity, methoxypolyoxyethylene (23 mol) (meth) acrylate, methoxypolyoxyethylene (9 mol) (meth) acrylate, methoxypolyoxyethylene (40 mol) ( (Meth) acrylate, polyoxyethylene (23 mol) (meth) acrylate, polyoxyethylene (9 mol) (meth) acrylate, and polyoxyethylene (40 mol) (meth) acrylate are preferred (here, the number of moles in parentheses) Indicates the value of m in the general formula (1).

  The structural unit corresponding to the monomer (A) functions as a hydrophilic part in the copolymer, and forms fine particles when the copolymer is dispersed in an aqueous solvent, outside the fine particles containing the copolymer. It is considered to have a function of existing and improving the stability of the cosmetic composition. Details of the “fine particles” will be described later.

In addition, the cosmetic composition containing the copolymer of the present invention is considered to exhibit adhesiveness after hair application due to the crystallinity of the polyoxyalkylene group contained in the structural unit corresponding to the monomer (A). .
The copolymer of the present invention may contain a structural unit corresponding to one kind of monomer (A), or may contain a structural unit corresponding to two or more kinds of monomers (A). .

  In the copolymer of the present invention, the content of the structural unit corresponding to the monomer (A) is preferably 30% by weight or more, more preferably 35% by weight or more of the whole copolymer, while 80% It is preferably not more than wt%, more preferably not more than 70 wt%. When the content of the structural unit corresponding to the monomer (A) is not less than the above lower limit value, the copolymer has appropriate hydrophilicity, so that it can be easily dispersed in an aqueous solvent, and is not more than the above upper limit value. It is preferable because it can be blended without impairing moisture resistance.

<Structural unit corresponding to vinyl monomer (B)>
The vinyl monomer (B) represented by the general formula (2) (hereinafter sometimes referred to as “monomer (B)”) is not particularly limited as long as it is a monomer represented by the following general formula (2). .

(In general formula (2), R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents an alkyl group having 2 to 10 carbon atoms, p and q each represents an integer of 0 or 1, and p + q = 1. is there.)

R ⁴ in the general formula (2) is a hydrogen atom or a methyl group.

R ⁵ in the general formula (2) is a linear, branched or cyclic alkyl group having 2 to 10 carbon atoms, preferably a linear or branched alkyl group having 4 to 8 carbon atoms, more preferably 4 carbon atoms. A linear or branched alkyl group.
P and q in the general formula (2) each represent an integer of 0 or 1, and p + q = 1. Preferably p = 1 and q = 0.

  Specific examples of the monomer (B) include ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, and pentyl (meth) acrylate. , Cyclohexyl (meth) acrylate, ethylhexyl (meth) acrylate, ethyl (meth) acrylamide, propyl (meth) acrylamide, n-butyl (meth) acrylamide, isobutyl (meth) acrylamide, t-butyl (meth) acrylamide, pentyl (meth) ) Acrylamide, cyclohexyl (meth) acrylamide, ethylhexyl (meth) acrylamide and the like. Among these, it is preferable that a monomer (B) contains n-butyl (meth) acrylate, isobutyl (meth) acrylate, and t-butyl (meth) acrylate from the balance of the whole touch.

  The copolymer of the present invention may include a structural unit corresponding to one type of monomer (B), or may include a structural unit corresponding to two or more types of monomers (B). .

The structural unit corresponding to the monomer (B) has an effect of imparting hydrophobicity corresponding to the alkyl group having 2 to 10 carbon atoms of R ^{5 to} the copolymer, and the copolymer is dispersed in a continuous phase containing water. In this case, there is an effect of promoting the formation of copolymer fine particles.

  Further, the structural unit corresponding to the monomer (B) is compatible with the structural unit corresponding to the highly hydrophilic monomer (A) in the residue obtained by drying the copolymer such as a film. Separation may have occurred. In the present invention, the film strength is increased by the phase of the structural unit corresponding to the phase-separated monomer (B), and the hair-styling power derived from the adhesiveness generated by the structural unit corresponding to the monomer (A) is maintained, and high setting properties are achieved. It is thought that it is a factor of its maintenance power. Further, in this mechanism, it is presumed that the surface contaminated with sebum or the like is renewed by applying pressure, so that it can function repeatedly and can exhibit re-styling.

  In the copolymer of the present invention, the content of the structural unit corresponding to the monomer (B) is preferably 20% by weight or more, more preferably 22% by weight or more of the whole copolymer, It is preferably no more than wt%, more preferably no more than 65 wt%. When the content of the structural unit corresponding to the monomer (B) is not less than the above lower limit value and not more than the upper limit value, the copolymer has appropriate hydrophilicity while maintaining water resistance, and thus is easily dispersed in an aqueous solvent. Therefore, it is preferable.

  In the copolymer of the present invention, by containing a structural unit corresponding to the monomer (A) and a structural unit corresponding to the monomer (B), copolymerization is possible from the viewpoint of obtaining a non-water-soluble copolymer. In a total of 100 parts by weight of the structural unit corresponding to the monomer (A) and the structural unit corresponding to the monomer (B) in the coalescence, 35 to 60 parts by weight of the structural unit corresponding to the monomer (A) and the monomer (B It is preferable that 22 to 65 parts by weight of a structural unit corresponding to

<Constitutional unit corresponding to vinyl monomer (C)>
The copolymer of the present invention further corresponds to a vinyl monomer (C) represented by the following general formula (3) and / or general formula (4) (hereinafter sometimes referred to as “monomer (C)”). It is preferable to have a structural unit.

  The monomer (C) is a vinyl monomer having a highly polar functional group containing a nitrogen atom, and by containing a structural unit corresponding to the monomer (C), the copolymer of the present invention and hair containing a lot of amide groups, etc. It is inferred that a high unity feeling can be realized even in a place where there is a lot of movement in the hair such as a hair tip.

(In General Formula (3), R ⁶ represents a hydrogen atom or a methyl group, and R ⁷ and R ⁸ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.)

(In general formula (4), R ⁹ represents a hydrogen atom or a methyl group. R is 0 or 1, s is an integer satisfying 1 to 4. X is the following general formula (5) to (7). Any one of them.)

(In the general formulas (5) to (7), R ¹⁰ and R ¹¹ each independently represent an alkyl group having 1 to 4 carbon atoms, and R ¹² in the general formula (6) represents an alkyl group having 1 to 4 carbon atoms, or ^{_{- (CH 2) u -COO -}} (u is an integer from 1 to 4.) indicates one of and its salts).

In the general formula (3), R ⁷ and R ⁸ are preferably each independently a linear or branched alkyl group having 1 to 4 carbon atoms, and R ⁷ and R ⁸ are particularly the same alkyl group. preferable.

In the general formula (4), r is preferably 1, and s is preferably 1-6. R ¹¹ and R ¹³ are preferably the same alkyl group.

  Among the monomers (C), specific examples of the vinyl monomer represented by the general formula (3) include N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N- Di (isopropyl) (meth) acrylamide, (meth) acrylamide and the like can be mentioned, and preferable examples include N, N-dimethyl (meth) acrylamide and N, N-diethyl (meth) acrylamide, and more preferable examples. N, N-dimethyl (meth) acrylamide may be mentioned.

  Further, among the monomers (C), specific examples of the vinyl monomer represented by the general formula (4) include N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N- Examples thereof include dimethylaminopropyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide, or amphoteric compounds thereof, or amine oxide compounds thereof.

  Among these monomers (C), monomer (C) is N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, from the balance of the overall feel when used as a hair cosmetic. N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, or amphoteric compounds thereof, or amine oxides thereof, N, N-dimethylacrylamide, N, N-diethylacrylamide Preferably, methacrylamide is included.

  The copolymer of the present invention may include a structural unit corresponding to one type of monomer (C), or may include a structural unit corresponding to two or more types of monomers (C). .

  In the copolymer of the present invention, the content of the structural unit corresponding to the monomer (C) is preferably from 0.1 to 50% by weight, more preferably from 0 to 30% by weight, even more preferably from 1 to 25%. % By weight. It is preferable for the content of the structural unit corresponding to the monomer (C) to be not less than the above lower limit value and not more than the upper limit value because the re-styling property of the copolymer of the present invention can be maintained.

<Structural unit corresponding to vinyl monomer (D)>
The copolymer of the present invention comprises a vinyl monomer (D) having an alkyl group having 12 to 22 carbon atoms (hereinafter referred to as “monomer (D)”) in addition to the structural units corresponding to the monomers (A) and (B). It is preferable to include a structural unit corresponding to By including the structural unit corresponding to the monomer (D), the hydrophobicity of the hydrophobic group portion is increased, the phase separation of the polyoxyalkylene portion is promoted, and as a result, the endothermic amount is increased. The number of carbon atoms of the alkyl group of the monomer (D) is particularly preferably 16-20.

  Examples of the vinyl monomer (D) having an alkyl group having 12 to 22 carbon atoms include stearyl (meth) acrylate, behenyl (meth) acrylate, cetyl (meth) acrylate, lauryl (meth) acrylate, and the like.

  The copolymer of the present invention may include a structural unit corresponding to one type of monomer (D), or may include a structural unit corresponding to two or more types of monomers (D). .

  In the copolymer of the present invention, the content of the structural unit corresponding to the monomer (D) is preferably 0 to 40% by weight, more preferably 5 to 35% by weight, and particularly preferably 10 to 30% by weight. . When the content of the structural unit corresponding to the monomer (D) is not less than the above lower limit value, it is preferable from the viewpoint of blendability in water when the copolymer is used as a cosmetic composition, and is not more than the above upper limit value. It is preferable because the adhesiveness of the cosmetic composition is improved when the copolymer has a hydrophobic structure.

<Constitutional units corresponding to other monomers>
The copolymer of the present invention corresponds to a vinyl monomer other than the monomers listed above (hereinafter may be referred to as “monomer (E)”) as long as the effects of the present invention are not impaired. A structural unit may be contained.

  Examples of the monomer (E) include monoesters of ethylene glycol, 1,3-propylene glycol, and the like and (meth) acrylic acid; and esters in which the hydroxyl groups of the monoester are etherified with methanol, ethanol, or the like; Nonionic monomers such as (meth) acryloylmorpholine, hydroxymethylacrylamide, and hydroxyethylacrylamide; anionic monomers such as acrylic acid and methacrylic acid; N- (meth) acryloyloxyethyl-N, N, N-trimethylammonium chloride, N- [3- {N ′-(meth) acryloyloxyethyl-N ′, N′-diethylammonium} -2-hydroxypropyl]-(Meth) acryl having a cationic group such as N, N, N-triethylammonium chloride Acid S N- (meth) acryloylaminopropyl-N, N, N-trimethylammonium chloride, N- [3- {N ′-(meth) acryloylaminopropyl-N ′, N′-diethylammonium} -2- (Meth) acrylamides having a cationic group such as hydroxypropyl] -N, N, N-trimethylammonium chloride; diallyl quaternary ammonium salts such as N, N-dimethyl-N, N-diallylammonium chloride; L- Amino acid cationic monomers such as arginine and glycidyl methacrylate reaction products; vinyl acetate, vinyl alcohol, alkyl ethers of vinyl alcohol; styrene, α-alkylstyrene, butadiene, isoprene, propene, vinyl chloride, acrylonitrile, polyfunctional (meta Acrylate etc. It can be shown.

  The copolymer of the present invention may include a structural unit corresponding to one type of monomer (E), or may include a structural unit corresponding to two or more types of monomers (E). .

  In the copolymer of the present invention, the content of the structural unit corresponding to the monomer (E) is preferably 0 to 30% by weight, and more preferably 0 to 25% by weight.

<Method for producing copolymer>
The method for producing the copolymer of the present invention is not particularly limited. For example, by mixing monomers that give respective structural units or precursors thereof and copolymerizing them by a method such as solution polymerization, suspension polymerization, emulsion polymerization, or the like. Can be manufactured.

  The polymerization reaction is preferably performed in water and / or a hydrophilic solvent. Examples of the hydrophilic solvent include ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; alcohol solvents such as methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, and sec-butanol. Can be mentioned. These water and / or hydrophilic solvents may be used alone or in combination of two or more. Among these, it is preferable to use an alcohol solvent and / or water.

  A polymerization initiator may be used for the polymerization reaction. Examples of the polymerization initiator include 2,2′-azobisisobutyronitrile and 2,2′-azobis (2-methyl-N- (2-hydroxyethyl). -Pripionamide), dimethyl-2,2'-azobis (2-methylpropionate), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (4-methoxy-) 2,4-dimethylvaleronitrile), dimethyl-2,2′-azobisisobutyrate, 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (1-cyclohexanecarbonitrile) Azo compounds such as 2,2′-azobis (2-methyl-N- (2-hydroxyethyl) -propionamide), 2,2′-azobis (2-amidinopropane) dihydrochloride, , Dicumyl peroxide, di -t- butyl peroxide, peroxides such as lauroyl peroxide, persulfates or such that redox systems, can be used without particular limitation.

  The polymerization initiator is preferably used in the range of 0.01 to 5% by weight, more preferably in the range of 0.1 to 3% by weight, based on the total monomers.

  The polymerization reaction can be performed, for example, under an inert gas atmosphere such as nitrogen or argon, preferably at 30 to 120 ° C., more preferably at 40 to 100 ° C., usually for 1 to 30 hours. After completion of the polymerization, the produced copolymer may be isolated from the reaction solution by an appropriate means such as solvent distillation or addition of a poor solvent. The obtained copolymer can be used as it is or after further purification to produce the cosmetic composition of the present invention. Purification can be performed by appropriately selecting known methods such as reprecipitation, solvent washing, and membrane separation as needed.

  The copolymer of the present invention can have any structure such as a random copolymer, a block copolymer, or a graft copolymer, and is not particularly limited.

  Random copolymers can be synthesized by a method in which an initiator is added to a state in which all monomers used for polymerization are mixed and reacted at once, a method in which some or all of the monomers are gradually reacted while dropping, and the like. it can. It can also be dropped and polymerized while changing the monomer composition. The block copolymer can be synthesized using a known radical initiator or a catalyst. The graft copolymer can be synthesized by a method using a macromer having a vinyl functional group, a method of reacting polymers having a reactive functional group, or the like.

  Among them, those that can be synthesized from inexpensive raw materials without requiring a special step are desirable because of their high industrial utility value, and random copolymers that are most easily produced using ordinary raw materials are most preferable. .

  The copolymer of the present invention is obtained by the above-mentioned method as an aqueous dispersion in which fine particles containing the copolymer of the present invention are dispersed in a continuous phase containing water, preferably with a volume average particle diameter of 10 to 500 nm. Is preferred.

Here, examples of the medium other than water in the dispersion medium containing 30% by weight or more of water include one or more of those exemplified as the hydrophilic solvent used in the production of the copolymer. The content is more preferably 40 to 100% by weight or more.
In addition, the suitable range of water content and volume average particle diameter in the aqueous dispersion obtained in this manner is as described later.

2. Composition for Cosmetics The copolymer of the present invention has a high setting property and re-styling property, and further has a wide range of formulation freedom. It can be a composition. Among these, a cosmetic composition in which fine particles containing the copolymer of the present invention are dispersed in a continuous phase containing 30% by weight or more of water is particularly preferable.

  The term “fine particles” as used herein refers to fine particles formed by cohesion of hydrophobic groups in a copolymer by one or more copolymer molecules with respect to a continuous phase containing 30% by weight or more of water. In particular, any shape such as a spherical shape or a lump shape may be used. The fine particles only need to mainly contain the copolymer of the present invention, and one kind of copolymer may be used alone, or two or more kinds of copolymers may be used in combination.

  The fine particles containing the copolymer of the present invention may contain one or more polymers other than the copolymer of the present invention as long as the effects of the present invention are not impaired. Examples of such polymers include polyacrylic acid, partially hydrophobized polyacrylic acid (such as a copolymer of acrylic acid and a vinyl monomer and / or (alkoxy) polyalkylene glycol methacrylate), acrylic acid and And / or setting resins such as copolymers of vinyl monomers. The content of these in the fine particles is preferably 0 to 10% by weight based on the whole fine particles.

  The method for producing fine particles is not particularly limited, and examples thereof include a method of dissolving in a good solvent and precipitating with a poor solvent, a method of self-emulsification in a solvent, and a method of using a disperser.

  The volume average particle diameter of the fine particles dispersed in the continuous phase measured by the dynamic light scattering method is preferably 10 to 500 nm. The volume average particle diameter is more preferably 15 nm or more. Further, it is more preferably 200 nm or less, further preferably 150 nm or less, and particularly preferably 100 nm or less. It is preferable that the volume average particle diameter is not less than the above lower limit value, since the effect such as setting property is excellent, and if it is not more than the above upper limit value, the effect such as re-hair styling is excellent. The volume average particle size can be adjusted by changing the length and amount of the polyoxyalkylene group in the vinyl monomer (A) and the hydrophobicity and amount of the constituent unit (vinyl monomer) constituting the copolymer. .

  The amount of water in the continuous phase of the cosmetic composition is preferably 30% by weight or more, more preferably 40% by weight or more. If the amount of water is more than this, fine particles are likely to be formed without dissolving the copolymer, and thus there is a tendency to have excellent hair-styling effects such as setting properties and re-hair-styling properties. Also, the amount of water in the continuous phase may be 100% by weight. Examples of the components other than water in the continuous phase include one or more of those exemplified as the hydrophilic solvent used in the production of the copolymer.

  The amount of the copolymer of the present invention contained in the cosmetic composition of the present invention is not particularly limited, but is preferably 0.1 to 20% by weight, particularly preferably 0.5 to 15% by weight. When the content of the copolymer of the present invention in the cosmetic composition is not less than the lower limit, hair styling properties are exhibited, and when the content is not more than the upper limit, excessive stickiness is reduced.

  In addition to the copolymer of the present invention, the cosmetic composition of the present invention can optionally contain components that can be usually blended in the cosmetic composition, as long as the effects are not impaired.

  Other components contained in the cosmetic composition are not particularly limited, and can be blended within a range that does not impair the objects and effects of the present invention. Examples of such components include the following, and a cosmetic composition can be produced by appropriately blending the following components.

  Other optional components that can be blended in the cosmetic composition will be described in detail below. However, each component described below does not include the copolymer of the present invention described in “1. Copolymer”.

<Polymer>
Examples of the water-soluble polymer include methyl cellulose and hydroxymethyl cellulose.
Examples of the cationic polymer include a cation-modified cellulose ether derivative, a cation-modified galactomannan polysaccharide, polydimethyl diallyl ammonium halide, and a copolymer of dimethyl diallyl ammonium halide and acrylamide.
Examples of the anionic polymer include acrylic acid derivatives (polyacrylic acid and salts thereof, acrylic acid / acrylamide / ethyl acrylate copolymer and salts thereof, acrylic acid / acrylic acid alkyl ester / steares 20 methacrylate copolymer and salts thereof) Etc.), methacrylic acid derivatives, crotonic acid derivatives and the like.
Examples of nonionic polymers include acrylic acid derivatives (hydroxyethyl acrylate / methoxyethyl acrylate copolymer, polyacrylamide, etc.) and vinylpyrrolidone derivatives (polyvinylpyrrolidone, vinylpyrrolidone / vinyl acetate copolymer, etc.).
Examples of amphoteric polymers include dimethyldiallylammonium chloride derivatives (acrylamide / acrylic acid / dimethyldiallylammonium chloride copolymer, acrylic acid / dimethyldiallylammonium chloride copolymer, etc.) and the like.
These polymers are preferably contained in an amount of 0.1 to 1% by weight of one or more of them in the cosmetic composition.

<Surfactant>
Examples of amphoteric surfactants include 2-undecyl-N, N, N- (hydroxyethylcarboxymethyl) -2-imidazoline sodium, 2-cocoyl-2-imidazolinium hydroxide-1-carboxyethyloxy disodium. Imidazoline-based amphoteric surfactants such as salts; betaine-based surfactants such as 2-heptadecyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, lauryldimethylaminoacetic acid betaine, alkylbetaines, amide betaines, sulfobetaines, etc. 1 type, or 2 or more types.

  As an anionic surfactant, α-olefin sulfonate, higher alcohol sulfate ester salt, polyoxyethylene alkyl ether sulfate ester salt, paraffin sulfonate, polyoxyethylene alkyl ether carboxylate ester salt, alkyl sulfosuccinate, N Examples include those commonly used in cosmetic compositions such as -acyl-β-alanine salts, N-acyl glutamates, and acylmethyl taurate salts. Examples of the counter ion of these anionic surfactants include one or more of sodium, potassium, ammonium, triethanolamine, diethanolamine and the like.

  Examples of the hydrophilic nonionic surfactant include polyoxyethylene (hereinafter sometimes abbreviated as POE) sorbitan fatty acid esters (for example, POE sorbitan monooleate, POE sorbitan monostearate, POE sorbitan monooleate). POE sorbite fatty acid esters (eg, POE sorbite monolaurate, POE sorbite monooleate, POE sorbite pentaoleate, POE sorbite monostearate, etc.); POE glycerin fatty acid esters (eg, POE glycerol monostearate, POE glycerol monoisostearate, POE monooleate such as POE glycerol triisostearate, etc.); POE fatty acid esters (for example, POE dies) Allate, POE monodiolate, ethylene glycol distearate, etc.); POE alkyl ethers (eg, POE lauryl ether, POE oleyl ether, POE stearyl ether, POE-behenyl ether, POE-2-octyldodecyl ether, POE cholestanol ether, etc.) Pluronic type (for example, pluronic and the like); POE / polyoxypropylene (hereinafter sometimes abbreviated as POP) alkyl ethers (for example, POE / POP cetyl ether, POE / POP-2-decyltetradecyl ether, POE / POP monobutyl ether, POE / POP hydrogenated lanolin, POE / POP glycerin ether, etc.); Tetra POE / tetra POP ethylenediamine condensates (eg, Tetronic, etc.) POE castor oil hydrogenated castor oil derivatives (eg POE castor oil, POE hydrogenated castor oil, POE hydrogenated castor oil monoisostearate, POE hydrogenated castor oil triisostearate, POE hydrogenated castor oil monopyroglutamic acid monoisostearic acid diester, POE hydrogenated castor oil maleic acid etc.); POE beeswax lanolin derivatives (eg POE sorbite beeswax etc.); alkanolamides (eg coconut oil fatty acid diethanolamide, lauric acid monoethanolamide, fatty acid isopropanolamide etc.); POE propylene glycol fatty acid 1 type or 2 types or more, such as ester; POE alkylamine; POE fatty acid amide; sucrose fatty acid ester; alkylethoxydimethylamine oxide;

  Cationic surfactants include alkyltrimethylammonium salts (eg, stearyltrimethylammonium chloride, lauryltrimethylammonium chloride, etc.), alkylpyridinium salts (eg, cetylpyridinium chloride, etc.), distearyldimethylammonium dialkyldimethylammonium chloride, (N, N′-dimethyl-3,5-methylenepiperidinium), alkyl quaternary ammonium salt, alkyldimethylbenzylammonium salt, alkylisoquinolinium salt, dialkyl morpholinium salt, POE alkylamine, alkylamine salt , Polyamine fatty acid derivatives, amyl alcohol fatty acid derivatives, benzalkonium chloride, benzethonium chloride and the like.

  Examples of the lipophilic nonionic surfactant include sorbitan fatty acid esters (for example, sorbitan monooleate, sorbitan monoisostearate, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan sesquioleate, Sorbitan trioleate, diglycerol sorbitan penta-2-ethylhexylate, diglycerol sorbitan tetra-2-ethylhexyl); glycerin polyglycerin fatty acids (for example, mono-cotton oil fatty acid glycerin, mono-erucic acid glycerin, sesquioleate glycerin, monostearin) Glycerin acid, α, α′-oleic acid pyroglutamate glycerin, monostearate glycerin malate, etc.); propylene glycol fatty acid esters (for example, Propylene glycol monostearate and the like); hardened castor oil derivative; and one or more of glycerin alkyl ether and the like.

  One or more of these surfactants can be contained in the cosmetic composition in a proportion of 5% by weight or less.

<Oil content>
Oils include linear polysiloxanes (dimethylpolysiloxane, methylphenylpolysiloxane, diphenylpolysiloxane, etc.), cyclic polysiloxanes (octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, etc.), three-dimensional Silicone resin, silicone rubber, various modified silicones (alkyl-modified silicone, phenyl-modified silicone, amino-modified silicone, polyether-modified silicone, fluorine-modified silicone, etc.), linear alcohol (lauryl alcohol, cetyl alcohol, Stearyl alcohol, behenyl alcohol, myristyl alcohol, oleyl alcohol, cetostearyl alcohol, etc.), branched chain alcohol (monostearyl glycerin agent) (Batyl alcohol), 2-decyltetradecinol, lanolin alcohol, cholesterol, phytosterol, hexyl decanol, isostearyl alcohol, octyldodecanol, etc.), hydrocarbon oils (liquid paraffin, squalane, petrolatum, microcrystalline wax) 1 type or 2 types or more of ester oils (jojoba oil, carnauba wax, octyldodecyl oleate), triglyceride oils (olive oil, beef tallow, coconut oil), fatty acids (stearic acid, oleic acid, ritinolic acid) It is done.
It is preferable to contain 0.1 to 20% by weight of one or more oils in the cosmetic composition.

<Other ingredients>
Other ingredients include natural extracts of animals and plants and derivatives thereof, organic acids such as citric acid and lactic acid, inorganic salts such as sodium chloride, amino acids (glutamic acid or salts thereof, arginine or salts thereof, glycine, etc.), solubilizers ( Ethanol, isopropanol, butanol, etc.), polyhydric alcohols (ethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,3-butylene glycol, glycerin, diglycerin, isoprene glycol, etc.), sugars (sorbitol, Maltitol, xylitol, glucose, fructose, mannitol, inositol, etc.), polymers such as hyaluronic acid, antioxidants, UV absorbers, bactericides, preservatives, chelating agents, fragrances, colorants, higher fatty acids, Nebazai, sequestering agents (edetic acid salts, etc.), pH adjusting agent, may be appropriately blended foam boosters such as within a range not to impair the effects of the present invention.

3. Hair cosmetic The cosmetic composition of the present invention is used in any cosmetic used for hair and skin. Such cosmetics include, for example, shampoos, rinses, conditioners, treatments, hair dyes, permanents, out bath treatments, hair packs, hair waxes, hair sprays, hair foams, styling agents, hair setting agents, body Shampoo, makeup cleansing, hand soap, milky lotion, lotion, lotion, cream, beauty essence, sunscreen, foundation, lipstick, mascara, eye shadow, hair remover, etc. are widely included. Moreover, the usage form may include any of those that are applied to the skin, hair, and the like and rinsed after thoroughly blending, and those that are not washed away.

  The cosmetic composition of the present invention is particularly suitable as a hair cosmetic composition comprising the composition. As a hair cosmetic, it can take various forms such as lotion, mist, spray, milky lotion, cream, washes, etc.The hair cosmetic formulated with the cosmetic composition of the present invention has excellent initial setting properties, When the hair is disturbed by wind or the like, free re-styling is possible.

  The cosmetic composition of the present invention is particularly suitable as a hair cosmetic that has a re-arrangement that can be rearranged while suppressing the sticky feeling of the hair, and is particularly used as a hair wax among the hair cosmetics. preferable.

  EXAMPLES Specific examples of the present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples unless it exceeds the gist.

[Production of copolymer]
<Production of copolymer (1)>
A reactor equipped with a reflux condenser, a dropping funnel, a thermometer, a nitrogen gas inlet tube and a stirring device was charged with 100 parts by weight of ethanol and the monomers shown in Table 1, and the reactor was heated to 84 ° C. after substituting with nitrogen. . After 0.2 parts by weight of dimethyl-2,2′-azobis (2-methylpropionate) was charged into the reactor, the mixture was stirred with heating at 84 ° C. for 4 hours. Thereafter, 0.3 part by weight of dimethyl-2,2′-azobis (2-methylpropionate) was charged into the reactor and stirred for 4 hours twice to obtain a copolymer (1).

<Production of Copolymers (2) to (5) and Copolymers (8) to (10)>
Copolymers (2) to (5) and copolymers (8) to (10) were produced in the same manner as in the production of the copolymer (1) except that the monomers listed in Table 1 were used.

<Production of copolymer (6)>
A reactor equipped with a reflux condenser, a dropping funnel, a thermometer, a nitrogen gas inlet tube and a stirrer was charged with 87.2 parts by weight of ethanol and the monomers shown in Table 1, and the reactor was purged with nitrogen and heated to 84 ° C. did. After 0.2 parts by weight of dimethyl-2,2′-azobis (2-methylpropionate) was added to the reactor, the mixture was stirred with heating at 84 ° C. for 3 hours. Thereafter, 0.3 part by weight of dimethyl-2,2′-azobis (2-methylpropionate) was added to the reactor and stirred for 3 hours. Thereafter, the reactor was set to 75 ° C., 6.2 g of hydrogen peroxide was added, and the mixture was stirred for 3 hours. The reactor temperature was set to 80 ° C. and the mixture was further stirred for 10 hours to obtain a copolymer (6). It was.

<Production of copolymer (7)>
A copolymer (7) was produced in the same manner as in the production of the copolymer (6) except that the monomers listed in Table 1 were used.

[Measurement of physical properties of copolymer]
The copolymers (1) to (10) obtained above were measured for the following physical properties, and the results are shown in Table 1.

<Endotherm start point / endotherm>
Calorimetry was performed using “DSC-7” manufactured by Seiko Instruments Inc. 10 mg of a sufficiently dried copolymer sample is placed in a sample cell and sealed, and in the following temperature cycle, the thermal behavior from low temperature is measured and recorded at the second temperature rise, and the endothermic peak start temperature and endothermic amount are measured. did.
Temperature cycle: room temperature → −100 ° C. (temperature decrease at 50 ° C./min)→hold at −100 ° C. for 10 minutes → 100 ° C. (temperature increase at 10 ° C./min)→hold at 100 ° C. for 5 minutes → −100 ° C. (10 ° C. Decrease in temperature / minute) → Hold at -100 ° C for 5 minutes → 100 ° C (heat up at 10 ° C / minute)

<Water solubility>
9.9 g of water was added to 0.1 g of a sufficiently dried copolymer sample and sufficiently stirred with a stirrer. When the copolymer sample did not dissolve, heating (90 ° C.) / Stirring and cooling / stirring were repeated twice, and when the copolymer sample did not dissolve further, ultrasonic treatment (ultrasonic cleaner, 5 minutes) / stirring was performed. After performing these operations, the mixture was allowed to cool to below 30 ° C., and insoluble matters that could be visually confirmed were confirmed. When there is no insoluble matter that can be visually confirmed, volume average particle size is measured by performing dynamic light scattering measurement using Nanotrac 150 manufactured by Microtrac or particle size distribution measurement using ASVR manufactured by Microtrac. The diameter was measured and evaluated according to the following evaluation criteria.
○ (dissolves in water of less than 30 ° C): There is no insoluble matter visible in the sample,
Alternatively, the volume average particle diameter of the insoluble material is less than 50 μm × (does not dissolve in water less than 30 ° C.): is there invisible material visible in the sample,
Alternatively, the volume average particle size of insoluble matter is 50 μm or more

<Weight average molecular weight>
Using gel permeation chromatography (apparatus: manufactured by Tosoh Corporation, SC8010, SD8022, RI8020, CO8011, PS8010, column: TSK GEL G6600H manufactured by Tosoh Corporation), developing solvent: tetrahydrofuran), using polyethylene glycol as a standard substance, weight The average molecular weight was determined.

[Preparation of cosmetic composition]
Copolymers (1) to (10) were diluted with ethanol to a solid content of 20% by weight and then slowly dropped into a predetermined amount of water to prevent aggregation and further adjusted to a predetermined concentration with ethanol. A cosmetic composition having the composition shown in -2 was prepared.

[Evaluation of cosmetic composition]
The following evaluation was performed about the cosmetic composition obtained above, and the results are shown in Table-3. Table 3 also shows the volume average particle diameter of the copolymer fine particles in each cosmetic composition measured by the dynamic light scattering method using Nanotrack 150 manufactured by Microtrack.

<Initial hair styling>
The use panel of the cosmetic compositions obtained in each of the examples and comparative examples was tested by five evaluation panelists, and the setability (initial hairstyling) at the time of sample application to the hair was based on the following evaluation point criteria. And evaluated. Next, an average score of evaluation scores given by each person was calculated and evaluated based on the following evaluation criteria.
(Evaluation criteria)
5 points: very easy to set 4 points: easy to set 3 points: normal 2 points: difficult to set 1 point: very difficult to set (evaluation criteria)
4: Average score is 4 or more 3: Average score is 3 or more and less than 4 2: Average score is 2 or more and less than 3 1: Average score is 1 or more and less than 2

<Re-hair styling>
The use of cosmetic compositions obtained in each of the examples and comparative examples was tested by five evaluation panelists, and the hair was disturbed 3 hours after the sample was applied to the hair, and setability when set again ( The re-styling property was evaluated based on the following evaluation point criteria. Next, an average score of evaluation scores given by each person was calculated and evaluated based on the following evaluation criteria.
(Evaluation criteria)
5 points: very easy to set 4 points: easy to set 3 points: normal 2 points: difficult to set 1 point: very difficult to set
(Evaluation criteria)
4: Average score is 4 or more 3: Average hand is 3 or more and less than 4 2: Average score is 2 or more and less than 3 1: Average score is 1 or more and less than 2

<Feeling of hair unity>
0.3 g of the composition for cosmetics obtained in each Example and Comparative Example was applied to human hair (Burelux Co., Ltd.) having a length of 15 cm, a width of 3 cm, and a weight of 3 g, and dried at 50 ° C. for 1 hour. After that, a hair tip sample was prepared by leaving it in a constant temperature and humidity chamber at 23 ° C. and 60% humidity for 1 hour or more. After the comb was passed 60 times against the hair tip, the unity feel (grouping) of the hair tip when the shape of the hair tip was adjusted by hand was visually evaluated based on the following evaluation criteria.
(Evaluation criteria)
4: Well organized 3: Collected 2: Not organized 1: Not organized at all

<A feeling of unity maintenance of hair ends>
After applying 0.3 g of the sample sample obtained in each Example and Comparative Example to human hair (Burelux Co., Ltd.) having a length of 15 cm, a width of 3 cm, and a weight of 3 g, and drying at 50 ° C. for 1 hour, A hair tip sample was prepared by leaving it in a constant temperature and humidity chamber at 23 ° C. and a humidity of 60% for 1 hour or more. After the comb is passed 60 times against the tip of the hair, the shape of the tip of the tip is adjusted by hand, and then the tip of the tip of the hair is maintained after holding the root of the tip and shaking the tip of the hair three times. The visual evaluation was performed based on the following evaluation criteria.
(Evaluation criteria)
4: Maintaining unity well 3: Maintaining unity 2: Not maintaining unity 1: Not maintaining unity at all

[Evaluation of results]
(1) The cosmetic compositions of Examples 1 to 7 had good initial hairstyling, re-styling, hairy unity feeling, and hairy unity maintenance feeling. In addition, in Examples 4 to 7 including the copolymer in which the monomer (C) was blended, the unity feeling of the hair tips was particularly good.
(2) The cosmetic composition of Comparative Example 1 uses a copolymer that does not have an endothermic peak, but is inferior in styling, and has a feeling of unity at the ends and a feeling of unity at the ends. It was inferior.
(3) The cosmetic composition of Comparative Example 2 uses a copolymer that does not contain a monomer corresponding to the monomer (A), but is inferior in the initial hair styling property and re-hair styling property. It was inferior in the sense of unity and maintenance of unity of the hair tips.
(4) The cosmetic composition of Comparative Example 3 uses a copolymer having high solubility in water, but has poor hair styling properties, a feeling of unity at the ends of the hair, and a feeling of unity of the ends of the ends. It was inferior.

Claims (9)

A copolymer comprising a structural unit corresponding to the vinyl monomer (A) represented by the following general formula (1) and a structural unit corresponding to the vinyl monomer (B) represented by the following general formula (2). A copolymer which does not dissolve in water of less than 30 ° C. and has an endothermic start point between −25 ° C. and 40 ° C. when the temperature is raised from a low temperature.

(In General Formula (1), R ¹ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ² represents an alkylene group having 2 to 4 carbon atoms, and R ³ represents a hydrogen atom or a methyl group. m represents an integer satisfying 1 to 100.)

(In general formula (2), R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents an alkyl group having 2 to 10 carbon atoms, p and q each represents an integer of 0 or 1, and p + q = 1. is there.) The copolymer of claim 1, further comprising a structural unit corresponding to a monomer represented by the following general formula (3) and / or a vinyl monomer (C) which is a monomer represented by the following general formula (4): Coalescence.

(In General Formula (3), R ⁶ represents a hydrogen atom or a methyl group, and R ⁷ and R ⁸ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.)

(In general formula (4), R ⁹ represents a hydrogen atom or a methyl group. R is 0 or 1, s is an integer satisfying 1 to 4. X is the following general formula (5) to (7). Any one of them.)

(In the general formulas (5) to (7), R ¹⁰ and R ¹¹ each independently represent an alkyl group having 1 to 4 carbon atoms, and R ¹² in the general formula (6) represents an alkyl group having 1 to 4 carbon atoms, or ^{_{- (CH 2) u -COO -}} (u is an integer from 1 to 4.) indicates one of and its salts). The copolymer of Claim 2 which contains the structural unit corresponded to each of vinyl monomer (A)-(C) with the following ratio with respect to the whole copolymer.
Vinyl monomer (A): 30 to 80% by weight
Vinyl monomer (B): 20 to 70% by weight
Vinyl monomer (C): 0.1 to 50% by weight   The copolymer according to any one of claims 1 to 3, wherein p = 1 in the general formula (2) representing the vinyl monomer (B).   Furthermore, the copolymer of any one of Claims 1 thru | or 4 containing the structural unit corresponding to the vinyl monomer (D) which has a C12-C22 alkyl group.   The copolymer according to any one of claims 1 to 5, wherein the weight average molecular weight is 5,000 or more and 2,000,000 or less.   An aqueous dispersion, wherein fine particles containing the copolymer according to any one of claims 1 to 6 are dispersed in a continuous phase containing water.   The aqueous dispersion according to claim 7, wherein the fine particles containing the copolymer according to any one of claims 1 to 6 are dispersed with a volume average particle diameter of 10 to 500 nm.   A cosmetic composition comprising the copolymer according to any one of claims 1 to 6.