Surface treatment composition

Abstract

To provide a surface treatment composition that has high hydrophilization effect, excels in compounding stability and adsorptivity, and can suppress shrinkage of hair when applied to the hair, a hair treatment agent containing the surface treatment composition, and a surface treatment method using the surface treatment composition.SOLUTION: A surface treatment composition contains following components (A)-(C): (A) a polymer at least containing a constitutional unit (a1) having a betaine group represented by Formula (1) and a constitutional unit (a2) having a cationic group represented by Formula (2), (B) an anionic polymer, and (C) an electrolyte. The proportion of the constitutional unit (a1) in all the constitutional units of the component (A) is 67 mol% or more and 99 mol% or less. There are also provided a hair treatment agent containing the surface treatment composition, and a surface treatment method that includes Step I of applying the surface treatment composition to a solid surface.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a surface treatment composition, a hair treatment agent containing the surface treatment composition, and a surface treatment method using the surface treatment composition. [Background technology]

[0002] Conventionally, methods for controlling the wettability of solid surfaces, such as hydrophilization treatment and water-repellent treatment, have been known as methods for treating solid surfaces. Among these, hydrophilization treatment of solid surfaces reduces the contact angle of the solid surface with water, making the solid surface more wettable to water, and is expected to have the effect of making it easier to remove dirt when washed when dirt adheres to the treated solid surface, and to prevent the dirt from re-adhering. In addition, it is expected to have effects such as anti-fogging and anti-static properties for glass, mirrors, etc., preventing frost formation on aluminum fins of heat exchangers, and imparting anti-fouling properties to the surfaces of bathtubs and toilets, and is therefore used in various industrial fields, and studies on solid surface treatments and methods have been progressing.

[0003] For example, Patent Document 1 describes a hydrophilic treatment agent composition containing a copolymer including a constituent unit containing a betaine group and a constituent unit having an aromatic group, an anionic surfactant, and water, with the aim of providing a hydrophilic treatment composition containing a hydrophilic treatment agent that exhibits excellent hydrophilicity for a long period of time. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-94434 Summary of the Invention [Problem to be solved by the invention]

[0005] In the field of hair cosmetics, shrinkage of hair can cause problems such as difficulty in managing hair, making it difficult to manage. In particular, even if a desired hairstyle is maintained when the hair is wet immediately after washing, shrinkage along the length of the hair occurs as the hair dries, and the hairstyle may not be able to achieve the desired length, volume, etc. According to research by the present inventors, when hair is wet, water present between hair strands generates a meniscus force that attracts the hair strands together, and this meniscus force prevents shrinkage. However, it has been found that drying of hair reduces the meniscus force between hair strands, causing shrinkage. The meniscus force between hair strands can be increased by reducing the contact angle of the hair surface with water. Therefore, there is a demand for a surface treatment composition that can impart high hydrophilicity to solid surfaces such as hair. In particular, the hair surface has a structure in which cuticle pieces that are highly hydrophobic are layered, while the areas near the edges of the cuticle pieces are hydrophilic. Therefore, the hair surface contains a mixture of hydrophobic and hydrophilic regions, and it is necessary to hydrophilize both of these regions. However, although the technology of Patent Document 1 can impart hydrophilicity to various solid surfaces, the hydrophilizing effect is still insufficient, particularly when applied to hair, and further improvement in the hydrophilizing effect of surface treatment compositions is desired. It has also been found that when the surface treatment composition is blended, precipitation of the components in the surface treatment composition occurs, resulting in the formation of coarse aggregates or precipitates, which may prevent the hydrophilization treatment from being carried out sufficiently. Furthermore, in order to maintain the hydrophilic effect even after washing with water or the like, it is also required to improve the adsorption of the components contained in the surface treatment composition. An object of the present invention is to provide a surface treatment composition that has a high hydrophilizing effect, is excellent in blend stability and adsorption, and is capable of suppressing hair shrinkage when applied to hair; a hair treatment agent containing the surface treatment composition; and a surface treatment method that uses the surface treatment composition. [Means for solving the problem]

[0006] The present inventors have found that the above-mentioned problems can be solved by a surface treatment composition containing a polymer including at least a constituent unit having a betaine group and a constituent unit having a cationic group, an anionic polymer, and an electrolyte, wherein the content of the constituent unit having a betaine group in the polymer is within a predetermined range. That is, the present invention provides the following [1] to [3]. [1] The following components (A) to (C): (A) A polymer containing at least a structural unit (a1) having a betaine group represented by the following formula (1) and a structural unit (a2) having a cationic group represented by the following formula (2): (B) Anionic polymer (C) Electrolyte Contains A surface treatment composition, in which the content of structural units (a1) in all structural units of component (A) is 67 mol % or more and 99 mol % or less. [ka] [In formula (1), R 1 ~R 3 are the same or different and represent a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, R 4 is an alkylene group having 1 to 4 carbon atoms, or -Y 1 -OPO3 - -Y 2 - indicates Y 1 and Y 2 are the same or different and represent alkylene groups having 1 to 4 carbon atoms, R 5 and R 6 are the same or different and represent hydrocarbon groups having 1 to 4 carbon atoms, X 1 is an oxygen atom or NR 7 represents a group, and R 7 represents a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, X 2 is R 4 When is an alkylene group having 1 to 4 carbon atoms, R 17 SO3 -, or R 17 COO - indicates R 17 represents an alkylene group having 1 to 4 carbon atoms which may have a hydroxyl group, and X 2 is R 4 Ga-Y 1 -OPO3 - -Y 2 When "-" is used, it represents a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms. [ka] [In formula (2), R 8 ~R 10 are the same or different and represent a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, X 3 is an oxygen atom or NR 18 represents a group, and R 18 represents a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, R 11 represents an alkylene group having 1 to 4 carbon atoms, X 4 is N + R 12 R 13 R 14 X 5 or NR 15 R 16 indicates R 12 ~R 16 are the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, and X 5 indicates an anion. [2] A hair treatment agent containing the surface treatment composition according to [1] above. [3] A surface treatment method, comprising step I of applying the surface treatment composition according to [1] above to a solid surface. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a surface treatment composition that has a high hydrophilizing effect, is excellent in blend stability and adsorption property, and further is capable of suppressing hair shrinkage when applied to hair; a hair treatment agent containing the surface treatment composition; and a surface treatment method that uses the surface treatment composition. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is an explanatory diagram of a method for calculating a shrink coefficient in measuring a shrink rate. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Surface treatment composition] The surface treatment composition of the present invention comprises the following components (A) to (C): (A) A polymer containing at least a structural unit (a1) having a betaine group represented by the following formula (1) and a structural unit (a2) having a cationic group represented by the following formula (2): (B) Anionic polymer (C) Electrolyte Contains The content of the structural unit (a1) in all structural units of the component (A) is 67 mol % or more and 99 mol % or less. [ka] [In formula (1), R 1 ~R 3 are the same or different and represent a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, R 4 is an alkylene group having 1 to 4 carbon atoms, or -Y 1 -OPO3 - -Y 2 - indicates Y 1 and Y 2 are the same or different and represent alkylene groups having 1 to 4 carbon atoms, R 5 and R 6are the same or different and represent hydrocarbon groups having 1 to 4 carbon atoms, X 1 is an oxygen atom or NR 7 represents a group, and R 7 represents a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, X 2 is R 4 When is an alkylene group having 1 to 4 carbon atoms, R 17 SO3 - , or R 17 COO - indicates R 17 represents an alkylene group having 1 to 4 carbon atoms which may have a hydroxyl group, and X 2 is R 4 Ga-Y 1 -OPO3 - -Y 2 When "-" is used, it represents a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms. [ka] [In formula (2), R 8 ~R 10 are the same or different and represent a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, X 3 is an oxygen atom or NR 18 represents a group, and R 18 represents a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, R 11 represents an alkylene group having 1 to 4 carbon atoms, X 4 is N + R 12 R 13 R 14 X 5 or NR 15 R 16 indicates R 12 ~R 16 are the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, and X 5 indicates an anion.

[0010] According to the present invention, the composition has a high hydrophilic effect, is excellent in blend stability and adsorption, and furthermore, when applied to hair, can suppress hair shrinkage. The reason for these effects is not clear, but it is thought to be as follows. The surface treatment composition of the present invention contains the above components (A) to (C), and therefore, component (A) and component (B) can be dissolved in the system by component (C), which is thought to inhibit precipitation of the components in the surface treatment composition and improve blend stability. When the surface treatment composition of the present invention is applied to an object to be treated and diluted by washing with water or the like, the concentration of component (C) in the system decreases, causing a polyion complex formed by the interaction of the cationic groups of component (A) and the anionic groups of component (B) to precipitate. This polyion complex can be effectively adsorbed onto the surface of the object to be treated, improving the adsorption properties of the surface treatment composition, and the hydrophilic betaine groups of component (A) can impart high hydrophilicity to the object to be treated. When the surface treatment composition of the present invention is applied to hair, as described above, the polyion complex effectively adsorbs onto the surface of the hair, which is the object to be treated, and the hydrophilic betaine group of component (A) can impart high hydrophilicity to the hair surface, which is thought to increase the meniscus force between the hair strands and suppress hair shrinkage.

[0011] <Component (A)> The surface treatment composition of the present invention contains, as component (A), a polymer containing at least a structural unit (a1) having a betaine group represented by formula (1) above and a structural unit (a2) having a cationic group represented by formula (2) above.

[0012] [Structural unit (a1)] The structural unit (a1) is a structural unit having a betaine group represented by the above formula (1). The structural unit (a1) is preferably a structural unit having a sulfobetaine group, a phosphobetaine group, or a carbobetaine group. The structural unit (a1) may be one type, or may be two or more different types of structural units. The structural unit (a1) is, for example, a structural unit derived from a monomer (a1′) represented by the following formula (1′).

[0013] [ka] [In formula (1'), R 1 ~R 6 , X 1 , X 2 is the same as above.]

[0014] In formulas (1) and (1′), R 1 ~R 6 , X 1 , X 2 Specific examples or preferred embodiments of the above are as follows, from the viewpoint of enhancing the hydrophilic effect, blend stability and adsorption, and enhancing the effect of inhibiting hair shrinkage. R 1 and R 2 is preferably a hydrogen atom. R 3 is preferably a hydrogen atom or a methyl group, more preferably a methyl group. X 1 is preferably an oxygen atom. R 4 is preferably an alkylene group having 1 to 4 carbon atoms, more preferably an alkylene group having 2 or 3 carbon atoms, and even more preferably an alkylene group having 2 carbon atoms. R 5 and R 6 is preferably a methyl group or an ethyl group, more preferably a methyl group. X 2 is R 4 When is an alkylene group having 1 to 4 carbon atoms, R 17 SO3 - , or R 17 COO - and preferably R 17 SO3 - R 17represents an alkylene group having 1 to 4 carbon atoms which may have a hydroxyl group, is preferably an alkylene group having 1 to 3 carbon atoms or a hydroxyalkylene group having 2 to 4 carbon atoms, is more preferably an alkylene group having 1 to 3 carbon atoms, is even more preferably an alkylene group having 2 or 3 carbon atoms, and is still more preferably an alkylene group having 3 carbon atoms. X 2 is R 4 Ga-Y 1 -OPO3 - -Y 2 When it is -, it is a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, preferably a hydrocarbon group having 1 to 4 carbon atoms, and more preferably a methyl group.

[0015] The structural unit (a1) is preferably a structural unit derived from a monomer having a sulfobetaine group, such as N-(3-sulfopropyl)-N-(meth)acryloyloxyethyl-N,N-dimethylammonium betaine or N-(3-sulfopropyl)-N-(meth)acryloylamidopropyl-N,N-dimethylammonium betaine; a monomer having a phosphobetaine group, such as 2-methacryloyloxyethyl phosphorylcholine; or a monomer having a carbobetaine group, such as N-carboxymethyl-N-(meth)acryloyloxyethyl-N,N-dimethylammonium betaine or N-carboxymethyl-N-(meth)acryloylamidopropyl-N,N-dimethylammonium betaine. More preferably, it is a structural unit derived from at least one selected from a monomer having a sulfobetaine group and a monomer having a phosphobetaine group, even more preferably a structural unit derived from a monomer having a sulfobetaine group, still more preferably a structural unit derived from at least one selected from N-(3-sulfopropyl)-N-(meth)acryloyloxyethyl-N,N-dimethylammonium betaine and N-(3-sulfopropyl)-N-(meth)acryloylamidopropyl-N,N-dimethylammonium betaine, and even more preferably a structural unit derived from N-(3-sulfopropyl)-N-(meth)acryloyloxyethyl-N,N-dimethylammonium betaine.

[0016] The content of the structural unit (a1) in all structural units of component (A) is, from the viewpoint of enhancing the hydrophilizing effect, blend stability and adsorption properties, and enhancing the effect of inhibiting hair shrinkage, at least 67 mol%, preferably at least 70 mol%, more preferably at least 75 mol%, even more preferably at least 80 mol%, still more preferably at least 85 mol%, still more preferably at least 90 mol%, still more preferably at least 93 mol%, and is at most 99 mol%, preferably at most 98 mol%, more preferably at most 97 mol%, even more preferably at most 96 mol%, and still more preferably at most 95 mol%. The content of each structural unit in all structural units of component (A) can be measured by analysis such as NMR, or can be calculated from the charge ratio of each monomer during the production of component (A).

[0017] [Structural unit (a2)] The structural unit (a2) is a structural unit having a cationic group represented by the above formula (2). In the present invention, the term "cationic group" refers to a cationic group or a group that can be ionized to become a cationic group. Examples of the cationic group include a primary amino group, a secondary amino group, a tertiary amino group, and a quaternary ammonium group. The structural unit (a2) may be one type, or may be two or more different types of structural units. The structural unit (a2) is, for example, a structural unit derived from a monomer (a2') represented by the following formula (2').

[0018] [ka] [In formula (2'), R 8 ~R 11 , X 3 , X 4 is the same as above.]

[0019] In formulas (2) and (2'), R 8 ~R 11 , X 3 , X4 Specific examples or preferred embodiments of the above are as follows, from the viewpoint of efficiently forming a polyion complex to enhance the hydrophilic effect and the effect of suppressing hair shrinkage. R 8 and R 9 is preferably a hydrogen atom. R 10 is preferably a hydrogen atom or a methyl group, more preferably a methyl group. X 3 is preferably an oxygen atom. R 11 is preferably an alkylene group having 2 or 3 carbon atoms, and more preferably an alkylene group having 2 carbon atoms. X 4 is N + R 12 R 13 R 14 X 5 is preferred, and R 12 , R 13 , R 14 From the same viewpoint as above, each of R is preferably a methyl group or an ethyl group, and more preferably R 12 , R 13 , and R 14 is an ethyl group. R 15 and R 16 is preferably a methyl group or an ethyl group, more preferably a methyl group, from the viewpoint of enhancing the hydrophilic effect and facilitating the quaternization reaction. X 5 is preferably a halogen ion or C2H5SO4 - and more preferably C2H5SO4 - is.

[0020] The structural unit (a2) is preferably a structural unit derived from an N,N-(dialkylamino)alkyl(meth)acrylic acid or a quaternized product thereof, more preferably a structural unit derived from a quaternized N,N-(dialkylamino)alkyl(meth)acrylic acid, even more preferably a structural unit derived from at least one selected from the group consisting of a quaternized product of 2-(dimethylamino)ethyl (meth)acrylate, a quaternized product of 2-(diethylamino)ethyl (meth)acrylate, and a quaternized product of 3-(dimethylamino)propyl (meth)acrylate, and even more preferably a structural unit derived from diethyl sulfate of 2-dimethylaminoethyl (meth)acrylate. In this specification, "(meth)acrylic acid" means acrylic acid or methacrylic acid.

[0021] The content of the structural unit (a2) in all structural units of component (A) is, from the viewpoint of efficiently forming a polyion complex and enhancing the hydrophilizing effect, enhancing the effect of inhibiting hair shrinkage, and from the viewpoints of blend stability and adsorption, preferably at least 1 mol%, more preferably at least 2 mol%, even more preferably at least 3 mol%, still more preferably at least 4 mol%, still more preferably at least 5 mol%, and is preferably at most 30 mol%, more preferably at most 25 mol%, even more preferably at most 20 mol%, still more preferably at most 15 mol%, and still more preferably at most 10 mol%.

[0022] Component (A) may contain other structural units besides the structural units (a1) and (a2), provided that the effects of the present invention are not impaired. Examples of other structural units include structural units derived from other monomers, such as nonionic monomers, such as (meth)acrylic acid esters, alkyl(meth)acrylamides, vinylpyrrolidones, and styrene-based monomers, and anionic group-containing polymerizable unsaturated monomers. In the present invention, the term "anionic group" refers to an anionic group or a group that can be ionized to become an anionic group. Examples of the anionic group include a carboxyl group (-COOM), a sulfonic acid group (-SO3M), a phosphate group (-OPO3M2), etc. In the above chemical formula, M represents a hydrogen atom, an alkali metal, ammonium, or an organic ammonium. As used herein, "(meth)acrylamide" means methacrylamide or acrylamide.

[0023] Examples of the (meth)acrylic acid ester include (meth)acrylic acid esters having a straight-chain or branched alkyl group such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, iso-butyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-decyl (meth)acrylate, lauryl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate; (meth)acrylic acid esters having an alicyclic alkyl group such as cyclohexyl (meth)acrylate; and (meth)acrylic acid esters having a hydrocarbon group having 1 to 30 carbon atoms such as aromatic group-containing (meth)acrylic acid esters such as benzyl (meth)acrylate. esters; polyalkylene glycol (meth)acrylates such as polyethylene glycol (meth)acrylate (the average number of moles of alkylene oxide added is preferably 2 or more and 30 or less); alkoxypolyalkylene glycol (meth)acrylates such as methoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, and octoxy(polyethylene glycol / polypropylene glycol copolymer) (meth)acrylate (the average number of moles of alkylene oxide added is preferably 2 or more and 30 or less); and phenoxypolyalkylene glycol (meth)acrylates such as phenoxyethylene glycol (meth)acrylate and phenoxy(polyethylene glycol / polypropylene glycol copolymer) (meth)acrylate (the average number of moles of alkylene oxide added is preferably 2 or more and 30 or less). In this specification, "(meth)acrylate" means acrylate or methacrylate.

[0024] Examples of alkyl(meth)acrylamides include N-alkyl(meth)acrylamides having an alkyl group having 1 to 22 carbon atoms, such as N-ethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, Nt-butyl(meth)acrylamide, N,N-dimethylacrylamide, and N,N-diethyl(meth)acrylamide. Examples of the styrene-based monomer include styrene, α-methylstyrene, and 2-methylstyrene.

[0025] Examples of the anionic group-containing polymerizable unsaturated monomer include carboxyl group-containing polymerizable unsaturated monomers, sulfonic acid group-containing polymerizable unsaturated monomers, and phosphoric acid group-containing polymerizable unsaturated monomers, which are exemplified as component (B) described below.

[0026] The content of structural units other than the structural unit (a1) and the structural unit (a2) in all structural units of component (A) is preferably 30 mol% or less, more preferably 20 mol% or less, even more preferably 10 mol% or less, still more preferably 5 mol% or less, still more preferably 3 mol% or less, and even more preferably 1 mol% or less, and the content of other structural units may even be 0 mol%. Component (A) may contain other structural units derived from aromatic group-containing monomers, such as aromatic group-containing (meth)acrylic acid esters, styrene-based monomers, and phenoxypolyalkylene glycol (meth)acrylic acid esters. However, from the viewpoint of hydrophilization effect, the content of structural units derived from aromatic group-containing monomers in all structural units of component (A) is preferably 1 mol% or less, more preferably 0.5 mol% or less, even more preferably 0.1 mol% or less, still more preferably 0.05 mol% or less, and even more preferably, component (A) does not contain any structural units derived from aromatic group-containing monomers.

[0027] The total amount of the structural units (a1) and (a2) within all structural units of component (A) is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, still more preferably 95 mol% or more, still more preferably 97 mol% or more, and even more preferably 99 mol% or more. The total amount of the structural units (a1) and (a2) within all structural units of component (A) may be 100 mol%.

[0028] The molar ratio of the structural unit (a1) to the structural unit (a2) [structural unit (a1) / structural unit (a2)] among all structural units of component (A) is preferably 3 or more, more preferably 4 or more, even more preferably 5 or more, still more preferably 7 or more, still more preferably 9 or more, still more preferably 10 or more, still more preferably 15 or more, and is preferably 50 or less, more preferably 40 or less, still more preferably 30 or less, still more preferably 25 or less, and still more preferably 20 or less.

[0029] (Production of component (A)) There are no particular limitations on the method for producing component (A), and examples include the following methods (x) and (y). (x) A method of copolymerizing raw material monomers including the monomer (a1') represented by the formula (1') and the monomer (a2') represented by the formula (2'). (y) A method of copolymerizing raw material monomers including a monomer represented by the following formula (1'-1) and a monomer (a2') represented by the formula (2'), followed by betaining with a betaining agent: Among these, method (y) is preferred from the viewpoint of availability of monomers and ease of production.

[0030] [ka] [In formula (1'-1), R 1 ~R 6 , X 1 is the same as formula (1), and the preferred embodiments are also the same as formula (1).

[0031] When method (y) is used, for example, when the structural unit (a1) is a structural unit derived from a monomer having a sulfobetaine group, raw material monomers including the monomer represented by formula (1'-1) above can be polymerized, and then betained by reacting with a compound represented by formula (1'-2) or (1'-3) below as a betaining agent, and among these, the compound represented by formula (1'-2) below is preferred.

[0032] [ka] [In formula (1'-2), n is 1 or 2, preferably 1.]

[0033] ZR 17 -SO3M (1'-3) [In formula (1'-3), Z is Cl or Br, preferably Cl; R 17 represents an alkylene group having 2 to 4 carbon atoms which may have a hydroxyl group, preferably a 2-hydroxypropylene group, and M represents Na or K.

[0034] The weight-average molecular weight of component (A) is preferably 3,000 or more, more preferably 5,000 or more, even more preferably 10,000 or more, and still more preferably 30,000 or more from the viewpoints of enhancing the hydrophilizing effect and enhancing the effect of suppressing hair shrinkage, and is preferably 1,000,000 or less, more preferably 500,000 or less, even more preferably 300,000 or less, and still more preferably 200,000 or less from the viewpoints of blend stability and adsorption. The weight-average molecular weight of component (A) can be measured by the method described in the Examples.

[0035] Component (A) preferably exhibits cationic properties as a whole. Component (A) may contain anionic groups other than the anionic groups contained in the betaine group in the polymer, as long as the effects of the present invention are not impaired. The cationic charge density of component (A) is preferably 0.01 meq / g or more, more preferably 0.05 meq / g or more, even more preferably 0.1 meq / g or more, still more preferably 0.15 meq / g or more, and preferably 1.0 meq / g or less, more preferably 0.8 meq / g or less, even more preferably 0.6 meq / g or less, still more preferably 0.4 meq / g or less, and still more preferably 0.2 meq / g or less. In the present invention, the cationic charge density of component (A) refers to the value obtained by subtracting the number of moles of anionic groups in component (A) / g × 1000 (anionic charge density; meq / g) from the number of moles of cationic groups in component (A) / g × 1000 (cationic charge density; meq / g). The cationic charge density of component (A) can be calculated from the types and molar ratios of the structural units that make up the polymer. The types and molar ratios of the structural units constituting the polymer can be measured by analysis such as NMR. Component (A) may also contain two or more polymers that exhibit cationic properties as a whole. In this case, the cationic charge density can be determined by calculating a weighted average of the cationic charge densities of the individual polymers and their blending amounts.

[0036] <Ingredient (B)> The surface treatment composition of the present invention contains an anionic polymer as component (B). In the present invention, the "anionic polymer" is a polymer that has an anionic group and exhibits anionic properties as a whole. Here, the term "anionic group" refers to an anionic group or a group that can be ionized to become an anionic group, as described above. Component (B) is preferably one or more selected from synthetic polymers or naturally occurring polymers having an anionic group, and salts thereof.

[0037] Examples of component (B) include polymers having a carboxy group, polymers having a sulfonic acid group, and polymers having a phosphoric acid group. Examples of the polymer having a carboxy group include poly(meth)acrylic acid, (meth)acrylic acid / maleic acid copolymer, (meth)acrylic acid / itaconic acid copolymer, (meth)acrylic acid / fumaric acid copolymer, (meth)acrylic acid / vinyl acetate copolymer, (meth)acrylic acid / 2-hydroxyethyl methacrylate copolymer, maleic acid / diisobutylene copolymer, maleic acid / styrene copolymer, benzoic acid formaldehyde condensate, benzoic acid / phenol / formaldehyde condensate, and salts thereof. Examples of polymers having sulfonic acid groups include polystyrene sulfonic acid, styrene sulfonic acid / styrene copolymer, 2-acrylamido-2-methylpropanesulfonic acid / (meth)acrylic acid copolymer, 2-acrylamido-2-methylpropanesulfonic acid / (meth)acrylic acid / acrylamide copolymer, naphthalenesulfonic acid formaldehyde condensate, methylnaphthalenesulfonic acid formaldehyde condensate, dimethylnaphthalenesulfonic acid formaldehyde condensate, poly[2-hydroxyethyl (meth)acrylate sulfate ester], 2-hydroxyethyl (meth)acrylate / 2-hydroxyethyl (meth)acrylate sulfate ester copolymer, sulfated poly[2-hydroxyethyl (meth)acrylate], and salts thereof. Examples of polymers having a phosphoric acid group include poly[(meth)acryloyloxyethylphosphonic acid], (meth)acryloyloxyethylphosphonic acid / 2-hydroxyethyl (meth)acrylate copolymer, naphthalenephosphonic acid formaldehyde condensate, poly[2-hydroxyethyl (meth)acrylate phosphate ester], 2-hydroxyethyl (meth)acrylate / 2-hydroxyethyl (meth)acrylate phosphate ester copolymer, phosphoric acid ester of poly[2-hydroxyethyl (meth)acrylate], and salts thereof.

[0038] The polymer backbone of the synthetic polymer is preferably a vinyl polymer. The vinyl polymer preferably contains a structural unit derived from an anionic group-containing polymerizable unsaturated monomer. Examples of the anionic group-containing polymerizable unsaturated monomer include a carboxy group-containing polymerizable unsaturated monomer, a sulfonic acid group-containing polymerizable unsaturated monomer, and a phosphoric acid group-containing polymerizable unsaturated monomer. Examples of the carboxyl group-containing polymerizable unsaturated monomer include (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, and 2-methacryloyloxymethylsuccinic acid. Examples of the sulfonic acid group-containing polymerizable unsaturated monomer include styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, and 3-sulfopropyl (meth)acrylate. Examples of the phosphoric acid group-containing polymerizable unsaturated monomer include vinylphosphonic acid, vinyl phosphate, bis(methacryloyloxyethyl) phosphate, diphenyl-2-acryloyloxyethyl phosphate, and diphenyl-2-methacryloyloxyethyl phosphate. Among these, preferred are carboxyl group-containing polymerizable unsaturated monomers, more preferred are one or more selected from (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid and 2-methacryloyloxymethylsuccinic acid, and even more preferred is (meth)acrylic acid.

[0039] The vinyl polymer may be a copolymer containing structural units derived from a monomer other than the anionic group-containing polymerizable unsaturated monomer, provided that the effects of the present invention are not impaired. Examples of such other monomers include (meth)acrylic acid esters, alkyl(meth)acrylamides, and aromatic group-containing monomers exemplified in the component (A) above, as well as (meth)acrylamides; hydroxyalkyl(meth)acrylates such as 2-hydroxyethyl(meth)acrylate; vinyl acetate; and N-vinyl-2-pyrrolidone. The above-mentioned monomers can be used either alone or in combination of two or more.

[0040] The vinyl polymer is preferably a vinyl polymer having a carboxy group, more preferably at least one selected from poly(meth)acrylic acid, (meth)acrylic acid / maleic acid copolymer, (meth)acrylic acid / itaconic acid copolymer, (meth)acrylic acid / fumaric acid copolymer, (meth)acrylic acid / vinyl acetate copolymer, (meth)acrylic acid / 2-hydroxyethyl methacrylate copolymer, maleic acid / diisobutylene copolymer, maleic acid / styrene copolymer, and salts thereof, and even more preferably at least one selected from poly(meth)acrylic acid and poly(meth)acrylate salts.

[0041] The naturally occurring polymer having an anionic group is a polymer obtained by extraction, purification, etc. from a natural product, or a chemically modified version of such a polymer. Examples of the naturally occurring polymer include cellulose derivatives such as carboxymethyl cellulose, carboxymethylmethyl cellulose, and carboxymethylethyl cellulose, or salts thereof; hyaluronates; colominates; dextran sulfates; and salts of heparin derivatives. Among these, at least one selected from cellulose derivatives and salts thereof is preferred, and carboxymethyl cellulose or a salt thereof is more preferred.

[0042] As described above, from the viewpoint of enhancing the hydrophilic effect, blend stability and adsorption, and enhancing the effect of suppressing hair shrinkage, component (B) is preferably one or more selected from polymers having a carboxy group, polymers having a sulfonic acid group, and polymers having a phosphate group, more preferably a polymer having a carboxy group, even more preferably at least one selected from vinyl polymers having a carboxy group, cellulose derivatives, and salts thereof, and even more preferably poly(meth)acrylic acid, (meth)acrylic acid / maleic acid copolymer, (meth)acrylic acid / itaconic acid copolymer, (meth)acrylic acid copolymer, The copolymer is preferably at least one selected from the group consisting of acrylic acid / fumaric acid copolymer, (meth)acrylic acid / vinyl acetate copolymer, (meth)acrylic acid / 2-hydroxyethyl methacrylate copolymer, maleic acid / diisobutylene copolymer, maleic acid / styrene copolymer, carboxymethyl cellulose, carboxymethyl methyl cellulose, carboxymethyl ethyl cellulose, and salts thereof, and more preferably at least one selected from poly(meth)acrylic acid, carboxymethyl cellulose, and salts thereof, and even more preferably at least one selected from poly(meth)acrylic acid and poly(meth)acrylate salts.

[0043] The weight-average molecular weight of component (B) is preferably 1,000 or more, more preferably 3,000 or more, even more preferably 5,000 or more, and even more preferably 10,000 or more from the viewpoint of enhancing the hydrophilic effect, adsorption properties, and hair shrinkage suppression effect, and is preferably 3,000,000 or less, more preferably 2,000,000 or less from the viewpoint of blend stability. The weight-average molecular weight of component (B) can be measured by the method described in the Examples.

[0044] The anionic charge density of component (B) is preferably −15 meq / g or more, more preferably −14 meq / g or more, even more preferably −13 meq / g or more, and preferably −1 meq / g or less, more preferably −3 meq / g or less, even more preferably −5 meq / g or less, still more preferably −7 meq / g or less, and even more preferably −10 meq / g or less. In the present invention, the anionic charge density of component (B) refers to the value obtained by subtracting the moles of cationic groups in component (B) / g×1000 (cationic charge density; meq / g) from the moles of anionic groups in component (B) / g×1000 (anionic charge density; meq / g). The anionic charge density (meq / g) of component (B) can be calculated from the type and molar ratio of the structural units derived from the monomer having an anionic group in the polymer. The types and molar ratios of the structural units constituting the polymer can be measured by analysis such as NMR. Component (B) is a polymer that exhibits anionic properties as a whole, but may contain cationic groups within the polymer as long as the effects of the present invention are not impaired. Component (B) may also contain two or more polymers that are anionic as a whole. In this case, the anionic charge density can be determined by calculating a weighted average of the anionic charge densities of the individual polymers and their blending amounts.

[0045] <Component (C)> The surface treatment composition of the present invention contains an electrolyte as component (C) from the viewpoints of enhancing the hydrophilizing effect, blend stability and adsorption properties, and enhancing the effect of inhibiting hair shrinkage. In the present invention, the term "electrolyte" refers to a compound that undergoes ion dissociation in water. Examples of component (C) include organic acids, inorganic acids, organic bases, inorganic bases, and salts thereof, from the viewpoint of dissolving component (A) and component (B) in the system by component (C), suppressing precipitation of the components in the surface treatment composition, and improving blend stability. Examples of organic acids include monocarboxylic acids such as formic acid, acetic acid, propionic acid, and benzoic acid; dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, and phthalic acid; polycarboxylic acids such as polyglutamic acid; hydroxycarboxylic acids such as glycolic acid, lactic acid, hydroxyacrylic acid, glyceric acid, malic acid, tartaric acid, and citric acid; acidic amino acids such as glutamic acid and aspartic acid; sulfonic acids such as methanesulfonic acid, N-methyltaurine, sulfamic acid, xylenesulfonic acid, p-toluenesulfonic acid, and benzenesulfonic acid; sulfate esters such as lauryl sulfate; and organic phosphate esters such as methyl phosphate and ethyl phosphate. Examples of inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, perchloric acid, carbonic acid, thiocyanic acid, and phosphoric acid. Examples of the organic base include alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine. Examples of inorganic bases include hydroxides of alkali metals such as potassium, sodium, and lithium. Ammonia may also be used as the inorganic base. Examples of salts include sodium chloride, potassium chloride, magnesium chloride, sodium citrate, potassium benzoate, ammonium chloride, sodium carbonate, dipotassium phosphate, and monoethanolamine sulfate. These may be used alone or in combination of two or more. Component (C) may be a combination of the above organic or inorganic acid and an organic or inorganic base to form a salt in the surface treatment composition.

[0046] Among these, from the viewpoint of blend stability, component (C) is preferably a salt, more preferably a water-soluble inorganic salt, whose solubility in 100 g of water at 20° C. is preferably 10 g or more, more preferably 20 g or more, and even more preferably 30 g or more. If component (C) is a water-soluble inorganic salt, the concentration of component (C) in the system can be reduced by applying the surface treatment composition to the object to be treated and then rinsing with water, allowing the polyion complex to be effectively adsorbed onto the surface of the object to be treated, imparting high hydrophilicity to the solid surface, and particularly when applied to hair surfaces, improving the effect of inhibiting hair shrinkage. From this perspective, component (C) is more preferably one or more selected from alkali metal salts and metal salts of Group 2 elements, even more preferably one or more selected from sodium chloride, potassium chloride, and magnesium chloride, even more preferably one or more selected from sodium chloride and potassium chloride, and even more preferably sodium chloride.

[0047] <Aqueous medium> The surface treatment composition of the present invention preferably contains an aqueous medium. Examples of the aqueous medium include water; lower alcohols such as ethanol and isopropyl alcohol; and low-molecular-weight diols and triols having 6 or less carbon atoms such as 1,3-butylene glycol, glycerin, ethylene glycol, and propylene glycol. Of these, water is preferred.

[0048] <Other ingredients> The surface treatment composition of the present invention may contain other components in addition to components (A) to (C) to the extent that the effects of the present invention are not impaired. Examples of other components include amphoteric surfactants, antioxidants, silicones, aromatic alcohols, polymers other than components (A) and (B), oils, vitamins, disinfectants, anti-inflammatory agents, antidandruff agents, preservatives, chelating agents, moisturizers, pearlescent agents, ceramides, fragrances, and ultraviolet absorbers.

[0049] The surface treatment composition of the present invention can be produced, for example, by blending components (A) to (C) and, if necessary, other components, and mixing them using a known stirring device, etc. The content or blending amount of each component in the surface treatment composition of the present invention is as follows.

[0050] The content or blending amount of component (A) in the surface treatment composition of the present invention depends on the cationic charge density of component (A), but from the viewpoints of enhancing the hydrophilizing effect, blending stability and adsorption properties, and enhancing the effect of suppressing hair shrinkage, is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.3% by mass or more, still more preferably 0.5% by mass or more, still more preferably 0.7% by mass or more, and is preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, still more preferably 10% by mass or less, still more preferably 5% by mass or less, still more preferably 3% by mass or less, still more preferably 2% by mass or less, and still more preferably 1.5% by mass or less.

[0051] The content or blending amount of component (B) in the surface treatment composition of the present invention varies depending on the anionic charge density of component (B), but from the viewpoints of enhancing the hydrophilizing effect, blend stability and adsorption properties, and enhancing the effect of suppressing hair shrinkage, is preferably 0.0001% by mass or more, more preferably 0.001% by mass or more, even more preferably 0.005% by mass or more, still more preferably 0.01% by mass or more, and is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, still more preferably 0.5% by mass or less, still more preferably 0.1% by mass or less, still more preferably 0.05% by mass or less, still more preferably 0.03% by mass or less.

[0052] The total content or total blending amount of component (A) and component (B) in the surface treatment composition of the present invention is, from the viewpoint of enhancing the hydrophilizing effect, from the viewpoint of adsorption properties, and from the viewpoint of enhancing the effect of suppressing hair shrinkage, preferably 0.0105% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, still more preferably 0.7% by mass or more, and still more preferably 0.9% by mass or more; and, from the viewpoint of the blending stability and handleability of the surface treatment composition, it is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, still more preferably 10% by mass or less, still more preferably 5% by mass or less, still more preferably 3% by mass or less, still more preferably 2% by mass or less, and still more preferably 1.5% by mass or less.

[0053] The content or blending amount of component (C) in the surface treatment composition of the present invention is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.3% by mass or more, still more preferably 0.5% by mass or more, and still more preferably 0.7% by mass or more, from the viewpoints of enhancing the hydrophilizing effect, blend stability, and enhancing the effect of inhibiting hair shrinkage; and from the viewpoints of enhancing the hydrophilizing effect, adsorption properties, and enhancing the effect of inhibiting hair shrinkage, it is preferably 15% by mass or less, more preferably 10% by mass or less, even more preferably 7% by mass or less, still more preferably 5% by mass or less, still more preferably 3% by mass or less, still more preferably 2% by mass or less, and still more preferably 1.5% by mass or less.

[0054] When water is used as the aqueous medium, the content or blending amount of the aqueous medium in the surface treatment composition of the present invention is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, still more preferably 80% by mass or more, still more preferably 90% by mass or more, and preferably 99% by mass or less.

[0055] The equivalent ratio of the amount of cations in component (A) represented by the following formula (I) to the amount of anions in component (B) represented by the following formula (II) [(amount of cations in component (A)) / (amount of anions in component (B))] is preferably 0.01 or more, more preferably 0.05 or more, even more preferably 0.1 or more, still more preferably 0.3 or more, still more preferably 0.5 or more, and still more preferably 0.7 or more, from the viewpoints of enhancing the hydrophilizing effect, blend stability and adsorption properties, and enhancing the effect of suppressing hair shrinkage, and is preferably 50 or less, more preferably 30 or less, still more preferably 10 or less, still more preferably 7 or less, still more preferably 5 or less, still more preferably 3 or less, still more preferably 2 or less, and still more preferably 1.5 or less. Amount of anions in component (A) = [anion charge density (meq / g) of component (A)] × [content or amount (g) of component (A) in the surface treatment composition] (I) Amount of cations of component (B) = [cation charge density (meq / g) of component (B)] × [content or amount (g) of component (B) in the surface treatment composition] (II)

[0056] [Surface treatment method] In the surface treatment method of the present invention, the surface treatment composition is preferably applied to a solid surface as a treatment target. That is, the surface treatment method of the present invention preferably includes a step I of applying the surface treatment composition to a solid surface. In the present invention, the term "solid surface" means the interface between a solid and the atmosphere. The solid is not particularly limited and examples thereof include glass, pottery, porcelain, enamel, tile, ceramics, wood, metals such as aluminum, stainless steel, brass, etc., synthetic resins such as polycarbonate, polyethylene, polypropylene, melamine resin, polyamide resin, ABS resin, FRP, etc., natural fibers such as cotton, silk, wool, etc., synthetic fibers such as polyester, nylon, rayon, etc., hair, nails, teeth, etc. The shape of the solid surface is not particularly limited. Among these, the solid surface is preferably a hydrophobic hard surface or a hair surface. In the present invention, a "hydrophobic hard surface" means a surface having a contact angle of 70° or more, and a "hydrophilic hard surface" means a surface having a contact angle of less than 70°. The contact angle can be measured by the method described in the Examples. The hydrophobic hard surface is preferably one or more selected from ceramics, metals, and synthetic resins. Furthermore, when the solid surface is a hair surface, the effect of inhibiting hair shrinkage can be improved.

[0057] The method for applying the surface treatment composition to the solid surface in step I is not particularly limited, and examples thereof include the following methods (i) to (iii). (i) A method of immersing a solid in a surface treatment composition (ii) A method of spraying or applying a surface treatment composition to a solid surface (iii) A method of cleaning a solid surface using a surface treatment composition according to a conventional method. The ambient temperature when the surface treatment composition is applied to a solid surface is preferably 5°C or higher, more preferably 10°C or higher, even more preferably 15°C or higher, from the viewpoint of enhancing the hydrophilizing effect and ease of work, and is preferably 50°C or lower, more preferably 40°C or lower, even more preferably 30°C or lower. The immersion time in the method (i) is preferably 0.1 minutes or more, more preferably 0.3 minutes or more, even more preferably 0.5 minutes or more, and even more preferably 1 minute or more, from the viewpoint of enhancing the hydrophilization effect and from the viewpoint of economy, and is preferably 60 minutes or less, more preferably 50 minutes or less. The spraying or application method in the above method (ii) can be appropriately selected depending on the size (area) of the solid surface, etc. After spraying, the solution may be thinly spread using a sponge or the like. The amount of the surface treatment composition of the present invention to be applied to a solid surface is, for example, preferably 1 ml in the case of a hydrophobic hard surface. 2 The maximum volume is 20 mL or more and 1,000 mL or less.

[0058] From the viewpoint of enhancing the hydrophilicity-imparting effect and enhancing the hair shrinkage-inhibiting effect, the surface treatment method of the present invention preferably includes Step II, in which the surface treatment composition applied to the solid surface in Step I is diluted. The dilution in Step II is preferably carried out using an aqueous medium. An example of a dilution method is washing the solid surface to which the surface treatment composition has been applied with an aqueous medium. This reduces the concentration of component (C) contained in the surface treatment composition attached to the solid surface, forming and precipitating a polyion complex that effectively adsorbs to the solid surface, and the betaine group contained in component (A) can impart high hydrophilicity to the solid surface. The aqueous medium used for washing is preferably water, for example. The water used as the aqueous medium is not particularly limited, and tap water, distilled water, ion-exchanged water, hard water, soft water, etc. can be used.

[0059] [Hair treatment agent] The hair treatment agent of the present invention contains the surface treatment composition. Because the surface treatment composition has an excellent effect of inhibiting hair shrinkage, the treatment agent can be used as a hair shrinkage inhibitor. Examples of the treatment agent include hair cleansers such as shampoos, and hair cosmetics such as conditioners, treatments, and hair dyes. Of these, conditioners are preferred from the viewpoint of obtaining the effects of the present invention and being able to easily suppress hair shrinkage through daily hair care activities. The formulation of the hair treatment agent is not particularly limited, and it can be in any formulation, such as a liquid, foam, paste, or cream. Of these formulations, the hair treatment agent is preferably in liquid form.

[0060] The method for treating the surface of hair preferably includes a step of applying the treatment agent to the hair. Examples of the method for applying the treatment agent include a method of painting, spraying, or casting the treatment agent onto the hair, and a method of immersing the hair in the treatment agent. The treatment may be applied to the hair in a dry or wet state. The ambient temperature when the treatment agent is applied is preferably 5 to 50°C, more preferably 15 to 45°C, from the viewpoint of efficient surface treatment. The application time of the treatment agent is preferably 5 seconds to 60 minutes, more preferably 5 seconds to 20 minutes. The application time of the treatment agent refers to the time during which the treatment agent is applied, sprayed, or poured onto the hair, or the time during which the hair is immersed in the treatment agent.

[0061] The hair surface treatment method preferably includes a step of applying the treatment agent to the hair and then washing the treated hair with an aqueous medium. This reduces the concentration of component (C) contained in the treatment agent, forming a polyion complex that precipitates and adsorbs to the hair surface, and the betaine group contained in component (A) imparts high hydrophilicity to the hair surface. As a result, the meniscus force between the hair strands increases, enhancing the effect of inhibiting hair shrinkage. There are no particular limitations on the method for washing the treated hair; for example, washing can be done by rinsing the hair with water using a known method.

[0062] A specific method for applying the hair treatment agent of the present invention to hair involves, for example, applying the hair cleanser to hair, lathering the hair, washing the hair, and then rinsing with water when the hair treatment agent is a hair cosmetic such as a conditioner, treatment, or hair dye, applying the hair cosmetic to hair, leaving it on for a short period of time (about 0.1 to 5 minutes) as needed, and then rinsing with water when the hair treatment agent is a hair cleanser such as a shampoo. By routinely repeating the above steps, hair shrinkage can be easily suppressed in a short period of time. [Example]

[0063] The present invention will be described below with reference to examples, but the present invention is not limited to these examples. Various measurements were carried out by the following methods.

[0064] (Weight average molecular weight of component (A)) Measurement was carried out using gel permeation chromatography under the following measurement conditions. [Measurement conditions] Column: Two "TSKgel α-M" (Tosoh Corporation) columns connected in series Column temperature: 40℃ Eluent: 0.15mol / LNa2SO4 / 1% by mass CH3COOH aqueous solution Flow rate: 1.0mL / min Detector: Differential refractive index detector Sample size: 5mg / mL Standard substance: pullulan

[0065] (Weight average molecular weight of component (B)) Measurement was carried out using gel permeation chromatography under the following measurement conditions. [Measurement conditions] Column: TSKgel G4000PW XL " + "TSKgel G2500PW XL (Tosoh Corporation) Column temperature: 40℃ Eluent: 0.2M phosphate buffer / CH3CN = 9 / 1 (volume ratio) Flow rate: 1.0mL / min Detector: Differential refractive index detector Sample size: 5mg / mL Standard substance: pullulan

[0066] Production Example 1 (Production of Polymer A1) (Process 1) A 1000 mL four-neck flask was charged with 126.30 g of ethanol (Fujifilm Wako Pure Chemical Industries, Ltd.) and heated to 78°C for reflux. A solution containing 181.12 g of 2-(dimethylamino)ethyl methacrylate (Fujifilm Wako Pure Chemical Industries, Ltd.), 23.60 g of a 90% aqueous solution of 2-(dimethylamino)ethyl methacrylate diethyl sulfate, and 53.20 g of ethanol, and a solution containing 5.83 g of 2,2'-azobis(2-methylbutyronitrile) (Fujifilm Wako Pure Chemical Industries, Ltd.) and 10.00 g of ethanol were added dropwise over 2 hours to the flask to allow for reaction. After the addition, the mixture was aged at 78°C for 4 hours and then cooled to obtain a polymer solution. The 90% aqueous solution of 2-(dimethylamino)ethyl methacrylate diethyl sulfate was obtained by mixing 2-(dimethylamino)ethyl methacrylate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and diethyl sulfate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) in a molar ratio of 1:1. (Process 2) A 1000 mL four-neck flask was charged with 94.70 g of the polymer solution obtained in step 1, 3.15 g of sodium bicarbonate (Fujifilm Wako Pure Chemical Industries, Ltd.), and 150.00 g of water, and the mixture was heated to 50°C. 38.70 g of 1,3-propane sultone (Tokyo Chemical Industry Co., Ltd.) was added dropwise over 1 hour to carry out the reaction. After the addition was complete, the mixture was aged at 50°C for 3 hours and then heated under reduced pressure at 90°C / 20 kPa for 2 hours to distill off the ethanol, yielding an aqueous solution containing Polymer A1 (N-(3-sulfopropyl)-N-methacryloyloxyethyl-N,N-dimethylammonium betaine / 2-(dimethylamino)ethyl diethyl methacrylate sulfate copolymer). The contents of the structural units (a1) and (a2), the weight-average molecular weight, and the charge density of Polymer A1 are shown in Tables 1 and 2.

[0067] Production Example 2 (Production of Polymer A2) In Production Example 1, the amounts of 2-(dimethylamino)ethyl methacrylate (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) were changed to 133.76 g, 73.60 g of a 90% aqueous solution of 2-(dimethylamino)ethyl methacrylate diethyl sulfate, 2.04 g of 2,2'-azobis(2-methylbutyronitrile) (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.), 7.15 g of sodium bicarbonate (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.), and 111.2 g of 1,3-propane sultone (manufactured by Tokyo Chemical Industry Co., Ltd.) were changed to obtain an aqueous solution containing Polymer A2 (N-(3-sulfopropyl)-N-methacryloyloxyethyl-N,N-dimethylammonium betaine / 2-(dimethylamino)ethyl methacrylate diethyl sulfate copolymer). Tables 1 and 2 show the content of the structural unit (a1), the content of the structural unit (a2), the weight average molecular weight, and the charge density of the polymer A2.

[0068] [Preparation of Surface Treatment Composition] Examples 1 to 12, Comparative Examples 1 to 5 According to the formulations shown in Tables 1 and 2, each surface treatment composition was prepared by mixing an aqueous solution containing the polymer obtained in each production example as component (A), each anionic polymer as component (B), sodium chloride as component (C), and water, and the following evaluations were carried out. In Comparative Example 5, an anionic surfactant was used instead of the anionic polymer. The results are shown in Tables 1 and 2.

[0069] (Evaluation of hydrophilic effect) The contact angle of the substrate surface-treated with the surface treatment composition was measured by the following method to evaluate the hydrophilic effect. (1) Preparation of the measurement substrate 10 mL of the prepared surface treatment composition was added to a 200 mL beaker, and a substrate (a polypropylene plate measuring 15 mm long x 25 mm wide x 1 mm thick) was immersed for 1 minute. Then, 190 mL of ion-exchanged water was added to dilute the solution. After dilution, the substrate was removed from the solution and washed with ion-exchanged water for 20 seconds. The substrate was then immersed in ultrapure water without drying and used as a substrate for measuring the underwater contact angle in the measurement (2) below. (2) Measurement of contact angle in water The measurement substrate prepared in (1) above was attached to a three-state sample stage and placed in a three-state cell containing ultrapure water. The cell containing the measurement substrate was placed on the stage of a fully automatic contact angle meter (Kyowa Interface Science Co., Ltd., "DM-701"), and the underwater contact angle after 0.2 seconds was determined by the tangent method after 1 μL of air was attached. The contact angle value is calculated by subtracting the measured underwater contact angle from 180°. The smaller the contact angle value, the higher the hydrophilic effect.

[0070] (Evaluation of blend stability) The state of the prepared surface treatment composition (10 mL) was visually observed immediately after preparation, and the blending stability was evaluated according to the following evaluation criteria. A score of 3 on the following evaluation criteria indicates excellent blending stability. A score of 3 on the following evaluation criteria indicates particularly suitable for practical use, and a score of 2 on the following evaluation criteria indicates suitable for practical use. [Evaluation criteria] 3: No precipitates are observed, and the solution is uniform and transparent. 2: Precipitates are observed, but they are fine and uniformly dispersed throughout, resulting in a cloudy appearance. 1: Precipitates are observed, and are locally agglomerated (separated) or precipitated.

[0071] (Evaluation of adsorption) 10 mL of the prepared surface treatment composition was diluted with 190 mL of ion-exchanged water. The state of the surface treatment composition after dilution was visually observed, and the adsorption was evaluated according to the following evaluation criteria. A rating of 3 on the following criteria indicates excellent adsorption. A rating of 3 on the following criteria indicates particularly suitable for practical use, and a rating of 2 on the following criteria indicates suitable for practical use. [Evaluation criteria] 3: Fine precipitates are observed that are uniformly dispersed throughout the solution, and the solution is cloudy. 2: No precipitates are observed, and the solution is uniform and transparent. 1: Coarse aggregates or precipitates are observed. Here, when treating an object to be treated using the surface treatment composition of the present invention, a polyion complex is formed and precipitated upon dilution, and it is believed that the polyion complex is adsorbed to the object to be treated, thereby enhancing the effectiveness of the hydrophilization treatment. Therefore, a composition in which the precipitates are fine and uniformly dispersed throughout and appear cloudy upon dilution was given a score of 3. Furthermore, a composition in which aggregates or precipitates are observed due to precipitation of the polyion complex was given a score of 1, as it is presumed that the surface of the object to be treated cannot be treated uniformly.

[0072] (Evaluation of handling) 50 mL of the prepared surface treatment composition was placed in a screw tube (No. 7, manufactured by Maruemu Co., Ltd.) and shaken up and down five times. Immediately after shaking, the time until the foam disappeared was measured visually and evaluated according to the following evaluation criteria. The shorter the time until the foam disappeared, the lower the viscosity of the surface treatment composition and the better the handleability tends to be. Therefore, if the composition is rated A according to the following evaluation criteria, the composition is excellent in handleability when performing surface treatment on an object to be treated. [Evaluation criteria] A: Time until foam disappears is less than 600 seconds B: Time until foam disappears is 600 seconds or more The viscosity of the surface treatment composition of Example 11, which was evaluated as Evaluation B, was measured using a Brookfield viscometer (Model TVB-10, manufactured by Toki Sangyo Co., Ltd.) and was found to be 68 mPa s. The measurement conditions were as follows: sample volume: 50 mL, Spindle No.: M2, and rotation speed: 30 rpm.

[0073] [Table 1]

[0074] [Table 2]

[0075] The components in Tables 1 and 2 are shown below. The blending amounts of each component in the tables are all the amount of active ingredient (% by mass). Polymer B1: Partially neutralized polyacrylic acid ("ACUSOL 445G Polymer" manufactured by The Dow Chemical Company, molecular weight: 4,500 (catalog value)) Polymer B2: Sodium carboxymethylcellulose (Daiichi Kogyo Co., Ltd. "Cellogen F-5A") Polymer B3: Polyacrylic acid ("Jurimer AC-10LHPK" manufactured by Toagosei Co., Ltd.) Anionic surfactant: alkyl (C10-16) ether ammonium sulfate, Kao Corporation "EMAL 125A", active ingredient amount 25% by mass

[0076] From Tables 1 and 2, it can be seen that the surface treatment compositions of the Examples have excellent blend stability and adsorption, and have smaller contact angles and higher hydrophilization effects than those of the Comparative Examples.

[0077] The shrinkage suppressing effect when the surface treatment composition of the present invention was applied to hair was evaluated by measuring the shrinkage rate by the method described below. (Evaluation of hair shrinkage suppression effect) Ten milliliters of each treatment solution prepared in Example 1 and Comparative Examples 1 and 2 was applied to 1 gram of African American hair tresses, left to stand for 1 minute, and then rinsed with tap water 20 times to obtain evaluation tresses. The resulting tresses were immersed in a plastic cup filled with tap water for 30 seconds, then quickly removed and left to stand in the air for 30 minutes. After 30 minutes, the maximum length (Lmax) and maximum width (Wmax) of the tresses, as shown in Figure 1, were measured, and the shrink coefficient (=Wmax / Lmax) was calculated. Here, tresses washed with plain shampoo of the composition shown below were immersed in a plastic cup filled with tap water, and the shrink coefficient immediately after being removed was taken as a "shrinkage rate" of 0. Similarly, tresses washed with the plain shampoo and then treated with a commercially available conditioner ("Essential Hair Conditioner" manufactured by Kao Corporation) were immersed in a plastic cup filled with tap water, and the shrink coefficient 30 minutes after being removed was taken as a "shrinkage rate" of 100. The shrink coefficients were normalized from these values ​​to determine the shrinkage rate. The results are shown in Table 3. <Plain shampoo composition> (Plain shampoo) (mass%) Sodium polyoxyethylene lauryl ether sulfate (Emar E-27C (active ingredient 27% by mass), manufactured by Kao Corporation) 42 Coconut oil fatty acid N-methylethanolamide (Aminone C-11S, manufactured by Kao Corporation) 3 Citric acid 0.2 Methylparaben 0.3 Purified water remainder Total 100

[0078] [Table 3]

[0079] Table 3 shows that the smaller the contact angle, the lower the shrinkage rate. This indicates that the hair surface can be made highly hydrophilic, resulting in an improved shrinkage suppression effect. [Industrial Applicability]

[0080] The surface treatment composition of the present invention can impart high hydrophilicity to a solid surface, and can provide a high shrinkage suppression effect, particularly when applied to hair.

Claims

1. The following components (A) to (C): (A) A polymer containing at least a structural unit (a1) having a betaine group represented by the following formula (1) and a structural unit (a2) having a cationic group represented by the following formula (2): (B) Anionic polymer (C) Electrolyte Contains the content of the structural unit (a1) in all structural units of the component (A) is 67 mol% or more and 99 mol% or less, the equivalent ratio of the amount of cations in component (A) represented by the following formula (I) to the amount of anions in component (B) represented by the following formula (II) [(amount of cations in component (A)) / (amount of anions in component (B))] is 0.1 or more and 10 or less, Amount of cations of component (A) = [cation charge density (meq / g) of component (A)] × [content or blending amount (g) of component (A) in the surface treatment composition] (I) Amount of anions of component (B) = [anion charge density (meq / g) of component (B)] × [content or blend amount (g) of component (B) in the surface treatment composition] (II) A surface treatment composition having a content of component (C) of 0.2 mass% or more and 10 mass% or less. 【Chemical 1】 [In formula (1), R １ ~R ３ are the same or different and represent a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, R ４ represents an alkylene group having 1 to 4 carbon atoms, or -Y １ -OPO ３ － -Y ２ - indicates Y １ and Y ２ are the same or different and represent alkylene groups having 1 to 4 carbon atoms, R ５ and R ６ are the same or different and represent hydrocarbon groups having 1 to 4 carbon atoms, X １ is an oxygen atom or NR ７ represents a group, and R ７ represents a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, X ２ is R ４ is an alkylene group having 1 to 4 carbon atoms, R １７ SO ３ － , or R １７ COO － indicates R １７ represents an alkylene group having 1 to 4 carbon atoms which may have a hydroxyl group, and X ２ is R ４ Ga-Y １ -OPO ３ － -Y ２ When it is -, it represents a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms. 【Chemistry 2】 [In formula (2), R ８ ~R １０ are the same or different and represent a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, X ３ is an oxygen atom or NR １８ represents a group, and R １８ represents a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, R １１ represents an alkylene group having 1 to 4 carbon atoms, X ４ is N ＋ R １２ R １３ R １４ X ５ or NR １５ R １６ indicates R １２ ~R １６ are the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms; X ５ indicates an anion.

2. 2. The surface treatment composition according to claim 1, wherein the content of the structural unit (a2) relative to all structural units of the component (A) is from 1 mol % to 30 mol %.

3. A surface treatment composition described in claim 1 or 2, wherein the equivalent ratio is 0.1 or more and 2 or less.

4. The surface treatment composition according to claim 3 , wherein the content of component (C) is 0.5% by mass or more and 5% by mass or less.

5. The surface treatment composition according to claim 4, wherein the total content of component (A) and component (B) is 0.9 mass % or more and 3 mass % or less.

6. 5. The surface treatment composition according to claim 1, wherein the weight average molecular weight of component (B) is 1,000 or more and 3,000,000 or less.

7. A hair treatment agent comprising the surface treatment composition according to any one of claims 1 to 6.

8. The hair treatment agent according to claim 7, which is a hair shrinkage inhibitor.

9. A surface treatment method comprising step I of applying the surface treatment composition according to any one of claims 1 to 6 to a solid surface.

10. The surface treatment method according to claim 9, further comprising a step II of diluting the surface treatment composition applied to the solid surface in the step I.

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