JP2013036012A - Cation-modified polyuronic acid or salt thereof - Google Patents

Abstract

Cationic modified polyuronic acid or a salt thereof having an excellent feel-improving effect, a method for producing the same, and hair cosmetics, when applied to hair cosmetics, maintains both smoothness during rinsing and improved hair firmness after drying Provide a feel-improving agent.
[1] A cation-modified polyuronic acid or a salt thereof having a structure in which a cationic group is introduced into polyuronic acid, [2] a feel improving agent having a cation-modified polyuronic acid or a salt thereof as an active ingredient, and [ 3] A method for producing cation-modified polyuronic acid or a salt thereof, in which cellulose is oxidized and then reacted with a cationizing agent, or cellulose is reacted with a cationizing agent and then oxidized.
[Selection figure] None

Description

  The present invention relates to a cation-modified polyuronic acid or a salt thereof, a production method thereof, and a feel improving agent having a cation-modified polyuronic acid or a salt thereof.

Many feel-improving agents are blended in many shampoos, conditioners, cosmetics and the like to fix the hair and skin and give it a moist and refreshing feel. Among them, polysaccharides having a cationic group are widely used as a feel improving agent. This is because it has a cationic group having a fixing property on an anionic surface such as hair and skin and a hydroxyl group having high moisture retention.
For example, Patent Document 1 proposes using cationized cellulose as a hair setting agent. Patent Document 2 proposes a cationized carboxymethylcellulose salt having excellent performance as a fixing agent and a surface modifier.

JP-A-5-112437 JP 2002-201202 A

However, when the cationized polysaccharide derivatives described in Patent Documents 1 and 2 are blended in a hair cosmetic, the feel of the hair after drying is improved, but the smoothness during rinsing is impaired. It was not satisfactory as an agent.
As described above, in hair cosmetics, there is a demand for an additive that improves the firmness of the hair after drying while maintaining the original smoothness of the conditioner.
The present invention provides a cation-modified polyuronic acid or a salt thereof having an excellent feel-improving effect, a method for producing the same, and a feel-improving agent that achieves both smoothness at the time of rinsing and improvement of hair stiffness after drying.

  The present inventors have found that cation-modified polyuronic acid or a salt thereof exhibits an effect superior to that of a conventional feel-improving agent, and has completed the present invention.

That is, the present invention provides the following [1] to [3].
[1] Cationic modified polyuronic acid or a salt thereof having a structure in which a cationic group represented by the following general formula (1) is introduced into polyuronic acid.

(In the formula, A represents a divalent hydrocarbon group having 1 to 6 carbon atoms which may be substituted with a hydroxyl group. R ¹ and R ² are the same or different and each represents a hydrocarbon group having 1 to 3 carbon atoms. R ³ represents a hydrocarbon group having 1 to ³ carbon atoms or a hydrogen atom, and Z ⁻ represents a monovalent anion.)
[2] A feel-improving agent having the cation-modified polyuronic acid or salt thereof of [1] as an active ingredient.
[3] After oxidizing cellulose, the cellulose is reacted with a cationizing agent represented by the following general formula (3), or after reacting cellulose with a cationizing agent represented by the following general formula (3), oxidation is performed. A method for producing a cation-modified polyuronic acid or a salt thereof.

Wherein Y is an atom or a functional group selected from the group consisting of an epoxy group, a halogen atom, a primary or secondary amino group, a hydroxyl group, and a thiol group, and A ′ is substituted with a hydroxyl group. Or a divalent hydrocarbon group having 1 to 6 carbon atoms, provided that when Y is an epoxy group, A ′ represents a divalent hydrocarbon group having 1 to 4 carbon atoms, R ^{1 to} R ³ , And Z ⁻ have the same meaning as in the general formula (1).)

  The cation-modified polyuronic acid or a salt thereof according to the present invention has an excellent feel-improving effect, and the feel-improving agent having the cation-modified polyuronic acid or a salt thereof as an active ingredient is applied to a hair cosmetic when rinsed. Both smoothness and improvement of hair elasticity after drying can be achieved.

<Cation-modified polyuronic acid>
The cation-modified polyuronic acid (hereinafter also referred to as “C-PU”) of the present invention is added to the polyuronic acid as a cationic group represented by the following general formula (1) (hereinafter simply referred to as “cationic group of the present invention”). Has a structure introduced).

The C-PU of the present invention only needs to have a structure in which the cationic group of the present invention is introduced into polyuronic acid, and is limited to those produced through the step of introducing a cationic group into polyuronic acid. For example, it may be produced by oxidizing a polysaccharide having a primary hydroxyl group into which the cationic group of the present invention has been introduced (for example, cellulose).
The structure of polyuronic acid that is the main chain of C-PU is not particularly limited as long as it has a structure obtained by oxidizing a primary hydroxyl group of a polysaccharide, but C-PU of the present invention is applied to hair cosmetics. From the viewpoint of smoothness at the time of rinsing and firmness of the hair after drying, a polyuronic acid structure having a structure obtained by oxidizing the primary hydroxyl group of cellulose is preferable. Here, the polyuronic acid only needs to have a structure obtained by oxidizing cellulose, and is not limited to one produced through a step of oxidizing cellulose.

  In the said General formula (1), A represents the C1-C6 bivalent hydrocarbon group which the hydroxyl group may substitute. Specific examples of the hydrocarbon group include methylene group, ethylene group, propylene group, trimethylene group, 1,3-butanediyl group, tetramethylene group, pentamethylene group, 2-methyltetramethylene group, 3-methylbutane-1, A divalent hydrocarbon group such as a 3-diyl group or a hexamethylene group; a divalent hydrocarbon group substituted with a hydroxyl group such as a 2-hydroxytrimethylene group, a 2-hydroxytetramethylene group or a 1-hydroxymethylethylene group; Etc. Among these, from the viewpoint of the availability of production raw materials, a hydroxyl group such as a divalent hydrocarbon group having 2 or 3 carbon atoms such as an ethylene group, a propylene group, or a trimethylene group, a 2-hydroxytrimethylene group, or a 1-hydroxymethylethylene group. A divalent hydrocarbon having 3 carbon atoms substituted with is preferable.

R < ¹ > and R < ² > of the said General formula (1) are the same or different, respectively, and show a C1-C3 hydrocarbon group. Examples of the hydrocarbon group having 1 to 3 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. Among these, a methyl group and an ethyl group are preferable from the viewpoint of easy availability of production raw materials.
R ^{3 in the} general formula (1) represents a hydrocarbon group having 1 to 3 carbon atoms or a hydrogen atom. Specific examples of the hydrocarbon group having 1 to 3 carbon atoms are the same as the specific examples of the hydrocarbon group having 1 to 3 carbon atoms represented by R ¹ and R ² . R ³ is preferably a methyl group, an ethyl group, or a hydrogen atom from the viewpoint of easy availability of production raw materials.
When several R < ¹ > exists in a molecule | numerator, they may mutually be same or different. The same applies to the case where a plurality of R ² and R ³ are present in the molecule.

Z ^{− in the} general formula (1) represents a monovalent anion. Monovalent anions include: hydroxy ions; halide ions such as chloride ions, bromide ions, or iodide ions; lower fatty acid ions having 2 to 4 carbon atoms such as acetate ions, propionate ions, or butyrate ions; methyl Examples thereof include lower alkyl sulfate ions having 1 to 3 carbon atoms such as sulfate ions and ethyl sulfate ions. Among these, from the viewpoint of improving touch, hydroxy ions and halide ions are preferable, hydroxy ions, chloride ions and bromide ions are more preferable, and chloride ions are more preferable.
The cationic group of the present invention can be substituted with a hydrogen ion of a carboxyl group in the C-PU molecule to form a counter ion within the molecule or between molecules, in which case Z ⁻ is unnecessary.

  The weight average molecular weight (Mw) of the C-PU of the present invention is 5,000 to 500,000 from the viewpoint of fixability to hair when applied to hair cosmetics, smoothness during rinsing and firmness after drying. Preferably, 7,000 to 300,000 are more preferable, 9,000 to 100,000 are more preferable, and 10,000 to 50,000 are particularly preferable. In addition, Mw of C-PU is a value obtained by gel permeation chromatography (GPC) measurement performed under the conditions described in the examples.

The C-PU of the present invention has the cationic group and the carboxyl group of the present invention.
Average number of the cationic groups of the present invention per condensed sugar (hereinafter also referred to as “constituent monosaccharide residue”) constituting the main chain of the C-PU of the present invention (hereinafter “average degree of substitution of cationic groups”) Is also preferably from 0.1 to 0.7, preferably from 0.15 to 0, from the viewpoint of fixability to hair when the C-PU of the present invention is applied to hair cosmetics and firmness after drying. .5 is more preferred.
The average number of carboxyl groups and salts thereof per monosaccharide residue constituting the C-PU of the present invention (hereinafter also referred to as “average degree of substitution of carboxyl groups”) is determined by using the C-PU of the present invention for hair cosmetics. From the viewpoint of smoothness during rinsing when applied, 0.3 to 1.0 is preferable, and 0.5 to 0.8 is more preferable.

A part or all of the carboxyl groups of the C-PU of the present invention may form a salt. In the present invention, when a part or all of the carboxyl groups of C-PU form a salt, this is referred to as a salt of cation-modified polyuronic acid (hereinafter also referred to as “C-PU salt”).
As a specific example of the counter ion other than the case where the carboxyl group of the C-PU of the present invention forms a salt and forms an ion pair with the cationic group of the present invention within the molecule or between the molecules, Examples include alkali metal ions such as sodium ion and potassium ion; protonated primary, secondary, or tertiary amine; quaternary ammonium ion or ammonium ion. Among these, alkali metal ions or ammonium ions are preferable and sodium ions are more preferable from the viewpoint of easy availability of production raw materials.
When the C-PU of the present invention is a salt, two or more counter ions may be used.

  The C-PU of the present invention is preferably a C-PU represented by the following general formula (2) from the viewpoint of smoothness at the time of rinsing when applied to a hair cosmetic, and firmness of the hair after drying.

  In the general formula (2), X is the same or different and represents a cationic group or a hydrogen atom represented by the general formula (1), and at least one of X in the molecule is a cationic group. Q is a nitrogen atom substituted by an alkyl group having 1 to 3 carbon atoms, a nitrogen atom to which a hydrogen atom is bonded, an atom selected from the group consisting of an oxygen atom and a sulfur atom, or a functional group, wherein X bonded to Q is In the case of a hydrogen atom, Q is an oxygen atom. m represents the average degree of polymerization of the constituent monosaccharide residue represented by the following general formula (4), and n represents the average degree of polymerization of the constituent monosaccharide residue represented by the following general formula (5).

In the general formulas (4) and (5), X and Q have the same meaning as in the general formula (2).
The coupling mode of C-PU represented by the general formula (2) may be a block or random.

In the case of C-PU represented by the general formula (2), the average substitution degree of the cationic group is obtained by dividing the average value (a) of the number of cationic groups per molecule by the sum of m and n. The average degree of substitution of carboxyl groups is expressed by the number [a / (m + n)], and the average value (b) of the number of carboxyl groups and their salts per molecule divided by the sum of m and n [b / (M + n)].
The average substitution degree of the cationic group in the case of C-PU represented by the general formula (2) and the preferred range of the average substitution degree of the carboxyl group are the above-mentioned average substitution degree of the cationic group of C-PU, And the same preferable range of the average degree of substitution of carboxyl groups.

The molar fraction [m / (m + n)] in which the constituent monosaccharide residue represented by the general formula (4) occupies the whole constituent monosaccharide residue is the C-PU of the present invention applied to hair cosmetics. From the viewpoint of smoothness at the time of rinsing, 0.3 to 1.0 is preferable, 0.5 to 0.97 is more preferable, and 0.6 to 0.95 is more preferable.
When Q in the general formulas (2) and (4) is a nitrogen atom substituted by an alkyl group having 1 to 3 carbon atoms, specific examples of the alkyl group having 1 to 3 carbon atoms include a methyl group and an ethyl group , N-propyl group, and isopropyl group. A C1-C3 alkyl group is determined by the structure of the cationizing agent used at the time of C-PU manufacture. From the viewpoint of the reactivity of the cationizing agent, a methyl group or an ethyl group is preferable, and a methyl group is more preferable. From the viewpoint of similar reactivity, when Q is a nitrogen atom substituted with an alkyl group having 1 to 3 carbon atoms or a nitrogen atom bonded with a hydrogen atom, Q is preferably a nitrogen atom bonded with a hydrogen atom.
From the viewpoint of the reactivity and availability of the cationizing agent, Q is preferably a nitrogen atom to which a hydrogen atom is bonded or an oxygen atom.

<Method for producing cation-modified polyuronic acid>
The method for producing C-PU of the present invention is not particularly limited, and polyuronic acid may be reacted with a cationizing agent represented by the following general formula (3) (hereinafter also simply referred to as “cationizing agent”). It can also be obtained by subjecting a polysaccharide having a primary hydroxyl group to oxidation of the primary hydroxyl group (hereinafter simply referred to as “oxidation”) and cationization with a cationizing agent. Oxidation and cationization of the polysaccharide may be performed either first or simultaneously, but are preferably performed separately from the viewpoint of the efficiency of the oxidizing agent and the cationizing agent.

In the general formula (3), Y is an atom or a functional group selected from the group consisting of an epoxy group, a halogen atom, a primary or secondary amino group, a hydroxyl group, and a thiol group. A ′ represents a C 1-6 divalent hydrocarbon group which may be substituted with a hydroxyl group. However, when Y is an epoxy group, A ′ represents a divalent hydrocarbon group having 1 to 4 carbon atoms. R ^{1 to} R ³ and Z ⁻ have the same meaning as in the general formula (1). Preferred embodiments and specific examples of the cationizing agent will be described in the section of [Cationizing agent] described later.

  Hereinafter, with respect to a method for producing C-PU using cellulose as a raw material as a polysaccharide having a primary hydroxyl group, a production method (A) for carrying out a step of reacting with a cationizing agent through an oxidation step, and a step of reacting with a cationizing agent The two methods of the manufacturing method (B) in which the oxidation process is performed through the process will be specifically described.

(A) A method for producing C-PU, in which cellulose is oxidized and then reacted with a cationizing agent [A-1: oxidation step].
The oxidation step is a step of oxidizing the primary hydroxyl group of cellulose to obtain polyuronic acid or a salt thereof.
〔cellulose〕
The cellulose used in the oxidation step is not particularly limited. For example, natural cellulose produced by refining wood pulp or produced by microorganisms, regenerated cellulose obtained by dissolving the natural cellulose in a solvent such as a copper ammonia solution and a morpholine derivative, and re-spun, and the cellulose is subjected to acid hydrolysis, alkali Fine cellulose that has been depolymerized by hydrolysis, enzymatic decomposition, blasting treatment, or the like, or fine cellulose that has been pulverized by mechanical force can be used.

From the viewpoint of water-solubility of C-PU, it is preferable to use low crystalline cellulose with reduced crystallinity.
In the case of cellulose, the degree of crystallization can be quantified as a crystallization index by adding a numerical value obtained from an X-ray crystal diffraction spectrum to the following formula (1).
Crystallization index (%) = [(I _22.6 −I _18.5 ) / I _22.6 ] × 100 (1)
[I _22.6 indicates the diffraction intensity of the lattice plane (002 plane) (diffraction angle 2θ = 22.6 °) in X-ray diffraction, and I _18.5 indicates the diffraction of the amorphous part (diffraction angle 2θ = 18.5 °). Indicates strength. ]

  The index of crystallization index is the change in the X-ray diffraction intensity on the 002 plane of the cellulose I-type crystal accompanying the change from crystal to amorphous. Therefore, if the crystal form contained in cellulose is only type I, theoretically, the crystallization index is 0 to 100%. In fact, since there are a plurality of crystal forms in cellulose, a negative value can also be taken when crystals other than type I are sufficiently destroyed and amorphized, but in the present invention, the above formula ( If a negative value is obtained in 1), the crystallization index is regarded as 0%.

Ordinary powdered cellulose is a so-called crystalline cellulose having a small amount of amorphous part and having a crystallization index of approximately 60 to 80% in accordance with the calculation formula (1).
When using low crystalline cellulose as a raw material of the present invention, the crystallization index is preferably 0 to 25%, more preferably 0 to 10% from the viewpoint of water solubility of the C-PU of the present invention. Preferably, it is 0%.
The method for preparing the low crystalline cellulose is not particularly limited. For example, it can be carried out according to the method described in the section “Preparation of Low Crystalline Powdered Cellulose” described in JP-A-2009-263641.

[Oxidation reaction]
In order to efficiently carry out the oxidation step by a method having a low environmental load, it is preferable to selectively oxidize the primary hydroxyl group of cellulose. In the section “Production of polyuronic acid salt” of JP-A-2009-263642 It is preferred to carry out the oxidation reaction in the manner described. That is, it is preferable to disperse low crystalline powdery cellulose in an aqueous system and perform an oxidation reaction in the presence of an N-oxyl compound using a co-oxidant or a co-catalyst as necessary.
The preferred embodiments of the N-oxyl compound, the co-oxidant, the cocatalyst used in the present oxidation step, and the amounts used thereof, the temperature of the oxidation reaction, and the pH of the reaction system are described in JP-A-2009-263541. The same as described in the section of [Production of polyuronic acid salt].

[Post-processing]
After completion of the oxidation step, purification by reprecipitation with methanol, ethanol, acetone or the like, ion exchange of salts, dialysis with a dialysis membrane, or the like can be performed as necessary.

[A-2: Cationization step]
This cationization step is a step of reacting the polyuronic acid obtained in [A-1: oxidation step] or a salt thereof with the cationizing agent represented by the general formula (3). It is desirable that polyuronic acid or a salt thereof is dissolved or dispersed in a solvent and reacted with a cationizing agent using a catalyst and / or a condensing agent as necessary.

[Cationizing agent]
The cationizing agent used in the present invention is represented by the general formula (3).
In Formula ^{(3), R 1 ~R 3} , Z - preferred aspect is, R ¹ ~R ^3, Z of each of the general formulas (1) ^- which is similar to the preferred aspects.
A ′ in the general formula (3) is preferably a divalent hydrocarbon group having 1 to 3 carbon atoms which may be substituted with a hydroxyl group from the viewpoint of easy availability of a cationizing agent, and has a reactive viewpoint. Therefore, the C1-C3 bivalent linear alkylene group which the hydroxyl group may substitute is more preferable.
The cationizing agent having an epoxy group or a halogen atom as Y in the general formula (3) can easily react with a carboxyl group of polyuronic acid or a salt thereof, and a hydroxyl group. A cationizing agent having a primary or secondary amino group, hydroxyl group, or thiol group as Y in the general formula (3) can be selectively reacted with a carboxyl group of polyuronic acid or a salt thereof.
Y in the general formula (3) is an epoxy group or an amino group from the viewpoint of the reactivity of the cationizing agent and the ability to form a chemically stable ether bond or amide bond after the reaction. preferable.

  Specific examples of the cationizing agent include glycidyltrialkylammonium chloride, glycidyltriethylammonium chloride, glycidyltrialkyl (C1-3) ammonium halide salts such as glycidyltrimethylammonium bromide; 3-chloro-2-hydroxypropyltrimethylammonium chloride; 3-halogeno-2-hydroxypropyltrialkyl (C1-3) ammonium halide salts such as; glycidyldialkyl (C1-3) amine hydrogen halide salts such as glycidyldimethylamine hydrochloride; 3-chloro-2-hydroxy 3-halogeno-2-hydroxypropyldialkyl (C1-3) amine hydrohalides such as propyldimethylamine hydrochloride; ω-dia such as 3-dimethylaminopropyl chloride hydrochloride Kill (C1-3) amino halogenated alkyl (C1-6) hydrogen halide salt; N, N-dimethyl-1,3-propanediamine hydrochloride, N, N-diethyl-1,3-propanediamine hydrochloride, N, N-dialkyl (C1-3) -α, ω-alkane (C1-6) diamine hydrochloride such as N, N-dimethyl-1,2-ethylenediamine hydrochloride; 3-dimethylamino-1-propanol hydrochloride Ω-dialkyl (C1-3) amino-α-alcohol (C1-6) hydrohalides such as; ω-dialkyl (C1-3) aminoalkanes such as 3-dimethylaminoalkane-1-thiol hydrochloride (C1 -6) -α-thiol hydrogen halide and the like.

Among these, glycidyltrimethylammonium chloride, glycidyltriethylammonium chloride, glycidyltrimethylammonium bromide, etc. from the viewpoint of the reactivity of the cationizing agent and the ability to form a chemically stable ether bond or amide bond after the reaction. Glycidyltrialkyl (C1-3) ammonium halide salt; glycidyldialkyl (C1-3) amine hydrochloride such as glycidyldimethylamine; N, N-dimethyl-1,3-propanediamine, N, N-diethyl- N, N-dialkyl (C1-3) -α, ω-alkane (C1-6) diamine hydrochloride such as 1,3-propanediamine hydrochloride and N, N-dimethyl-1,2-ethylenediamine hydrochloride is preferred. From the viewpoint of availability, glycidyltrimethyl Nmo chloride, N, N-dimethyl-1,3-propanediamine hydrochloride is more preferable.
Here, the hydrogen halide salts of amines such as glycidyl dialkyl (C1-3) amine hydrogen halide salt, N, N-dialkyl (C1-3) -α, ω-alkane (C1-6) diamine hydrochloride are In the cationization reaction, it may be added in the form of a free amine such as glycidyldialkyl (C1-3) amine, N, N-dialkyl (C1-3) -α, ω-alkane (C1-6) diamine.

  The amount of the cationizing agent can be adjusted as appropriate according to the amount of the cationic group introduced and the yield, but it is smooth when rinsing when the C-PU of the present invention is applied to a hair cosmetic. From the viewpoint of firmness of the hair after drying, 0.1 to 3 per mol of the constituent monosaccharide residue of the polyuronic acid obtained in [A-1: oxidation step], which is a raw material of the cationization step. The mole times are preferable, and 0.15 to 2 mole times is more preferable.

〔catalyst〕
A catalyst can be used in the cationization step as necessary.
Although it does not specifically limit as a catalyst, Basic catalysts, such as sodium hydroxide, potassium hydroxide, and an organic amine, are preferable.
The amount of the catalyst is not particularly limited as long as it is an effective amount capable of exhibiting these functions, but the reaction rate between polyuronic acid or a salt thereof used as a raw material for the cationization step and the cationizing agent, and after completion of the reaction From the viewpoint of the purification load, it is preferably 0.1 to 100% by mass, more preferably 1 to 30% by mass, and 5 to 20% by mass with respect to the raw material cellulose used in the oxidation step. Further preferred.

[Condensation agent]
When a cationizing agent having a primary or secondary amino group, hydroxyl group, or thiol group as Y in the general formula (3) is used, and the cationizing agent is selectively reacted with the carboxyl group of polyuronic acid or a salt thereof. The reaction is preferably carried out using a condensing agent.
The condensing agent is not particularly limited, and examples include condensing agents described in Synthetic Chemical Series Peptide Synthesis (Maruzen Co., Ltd., 1975), page 116, or Tetrahedron, 57, 1551 (2001).
Among these, 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorpholinium chloride is preferable from the viewpoint that water can be used as a solvent.

The amount of the condensing agent can be appropriately adjusted depending on the amount of the cationic group introduced and the yield, but from the viewpoint of the efficiency of the cationizing agent, 1 -5 mol times are preferable and 1-2 mol times are more preferable.
When using a condensing agent in a reaction using polyuronic acid salt as a raw material, it is preferable to carry out the reaction after converting the carboxylate of the polyuronic acid salt to a carboxyl group. As a method for converting to a carboxyl group, a method of adding an acid to the polyuronic acid salt or a method of lowering the pH of water when water is used as a solvent is preferable.

〔solvent〕
Examples of the solvent include water; alcohols having 1 to 6 carbon atoms such as methanol, ethanol, isopropanol, and tert-butanol; ketone compounds such as acetone and methyl ethyl ketone; N, N-dimethylformamide, dimethyl sulfoxide, and the like. Among these, water is preferable from the viewpoint of reducing environmental load. The said solvent can be used individually or in mixture of 2 or more types.
The amount of the solvent is preferably 1 to 1000 times, more preferably 3 to 100 times, and still more preferably 6 to 20 times the polyuronic acid or salt thereof obtained in [A-1: oxidation step].

[Reaction conditions]
The temperature of the cationization step is preferably 200 ° C. or lower, more preferably 100 ° C. or lower, further preferably 50 ° C. or lower, from the viewpoint of reaction selectivity and side reaction suppression, and the lower limit thereof is the reaction. From the viewpoint of speed, it is preferably −5 ° C. or higher.
Although reaction time may be suitably adjusted according to reaction rate, it is 0.1 to 24 hours normally, Preferably it is 1 to 10 hours.

[Post-processing]
After completion of the cationization step, purification by reprecipitation with methanol, ethanol, acetone or the like, ion exchange of salts, dialysis using a dialysis membrane, or the like can be performed as necessary.

(B) A method for producing C-PU, in which cellulose and a cationizing agent are reacted and then oxidized [B-1: cationization step]
This cationization step is a step of obtaining a cationized cellulose by reacting the hydroxyl group of cellulose with the cationizing agent represented by the general formula (3) to introduce a cationic group into the cellulose.
It is desirable to react the cellulose with a cationizing agent in the presence of a catalyst, if necessary, in the absence of a solvent or in a state dissolved or dispersed in a solvent.

〔cellulose〕
Specific examples and preferred embodiments of the cellulose used in the cationization step are the same as the cellulose described in [A-1: Oxidation step]. However, when the reaction is carried out by dissolving cellulose in a solvent, the crystallinity of the cellulose does not affect the cationization reactivity and the performance of the cation-modified polyuronic acid obtained through this step.

[Cationizing agent]
The preferred embodiments of R ^{1 to} R ³ , Z ⁻ and A ′ in the general formula (3) are the same as those described in the section [A-2: Cationization step].
Y is preferably an epoxy group or a halogen atom from the viewpoint of reactivity with a hydroxyl group.
Specific examples of the cationizing agent represented by the general formula (3) are the same as those described in the section [A-2: Cationization step], but from the viewpoint of reactivity with a hydroxyl group, glycidyl. Glycidyltrialkyl (C1-3) ammonium halide salts such as trimethylammonium chloride, glycidyltriethylammonium chloride, glycidyltrimethylammonium bromide; Glycidyldialkyl (C1-3) amine hydrogen halide salts such as glycidyldimethylamine hydrochloride are preferred From the viewpoint of availability, glycidyltrimethylammonium chloride is more preferable.
About the preferable aspect of the usage-amount of a cationizing agent, it is the same as that of the preferable aspect of the usage-amount of the cationizing agent of [A-2: Cationization process].

〔solvent〕
When the reaction is performed by dispersing cellulose in a solvent, the solvent is not particularly limited. Specific examples include aliphatic hydrocarbons or aromatic hydrocarbon solvents in addition to the solvents listed in [A-2: Cationization step].
When the reaction is carried out by dissolving cellulose in a solvent, examples of the solvent include cellulose solvents described on page 114 of Cellulose Science (Asakura Shoten, published 2000). Of these, dimethyl sulfoxide / carbon disulfide / amine mixed system, N, N-dimethylformamide / dinitrogen tetroxide mixed system, N-methylmorpholine N-oxide, and N, N-dimethylacetamide / lithium chloride system are preferable.

〔catalyst〕
In the cationization step, a catalyst can be used as necessary. The preferred mode of the type and amount of catalyst used is the same as that described in [A-2: Cationization step].

[Reaction conditions / post-treatment]
Preferred conditions for the reaction conditions and post-treatment are the same as those described in [A-2: Cationization step].

[B-2: Oxidation step]
This oxidation step is a step of oxidizing the primary hydroxyl group of the cationized cellulose obtained in [B-1: Cationization step].
In order to efficiently perform the oxidation step by a method having a low environmental load, it is preferable to selectively oxidize the primary hydroxyl group of cellulose. Instead of the low crystalline powdered cellulose, the above [B-1: cationization step It is preferable to oxidize by the method described in the section [Production of polyuronic acid salt] described in JP-A No. 2009-263641 except that the cationized cellulose obtained in the above is used.

[Post-processing]
A preferred mode of the post-treatment is the same as that described in [A-1: Oxidation step].

<Use of cationically modified polyuronic acid as a feel improver>
The cation-modified polyuronic acid or a salt thereof of the present invention can be applied to various fields as an active ingredient of a feel improving agent, and preferably applied to hair cosmetics, skin cosmetics, hair cleansers, skin cleansers. can do. In particular, when applied to hair cosmetics, it is preferable because both smoothness at the time of rinsing and improvement of hair sharpness after drying can be achieved.
When applied to hair cosmetics or skin cosmetics, the blending amount of the cation-modified polyuronic acid or a salt thereof of the present invention is preferably 0.01 to 20% by mass, and preferably 0.1 to 10% by mass from the viewpoint of the feeling improvement effect. % Is more preferable, and 0.2-5 mass% is still more preferable.

In addition to the cation-modified polyuronic acid or a salt thereof of the present invention, the cosmetics include, for example, polyhydric alcohols and oily components described in JP-A-7-304801 as components used in ordinary cosmetics. , Surfactants, vitamins, bactericides, anti-inflammatory agents, anti-dandruff agents, activators, cooling agents, UV absorbers, preservatives, inorganic salts, viscosity modifiers, pearlizing agents, perfumes, pigments, antioxidants An agent, a water-swellable clay mineral, a polysaccharide (excluding the cation-modified polyuronic acid or its salt of the present invention), a synthetic polymer, an inorganic pigment, or an organic pigment is appropriately blended within a range not impairing the effects of the present invention. be able to.
The cosmetic can be produced by a normal method, and its dosage form can be any dosage form such as liquid, cream, solid, powder, etc., but in particular liquid or cream Is preferred.

In addition, when the cation-modified polyuronic acid or a salt thereof of the present invention is applied to a hair cleanser or a skin cleanser, the blending amount is preferably 0.1 to 30% by mass, more preferably 0.2 to 10% by mass, 0.2-5 mass% is still more preferable.
The cleaning material contains various surfactants usually used in cleaning agents as long as the effects of the present invention are not impaired. Examples of the surfactant include surfactants described in JP-A-7-304801.
These surfactants may be used alone or in combination of two or more thereof, and the blending amount thereof varies depending on the dosage form, but is preferably 0.1 to 60% by mass, and 1 to 50% by mass in the cleaning material. Is more preferable.

In addition to the above-mentioned components, for example, polyhydric alcohols, oily components, surfactants, vitamins, bactericides, anti-inflammatory agents, anti-dandruff agents, and activation agents described in JP-A-7-304801 Agent, cooling agent, ultraviolet absorber, preservative, inorganic salt, viscosity modifier, pearlizing agent, fragrance, pigment, antioxidant, water-swelling clay mineral, polysaccharide (cation modified polyuronic acid of the present invention or its Synthetic polymers, inorganic pigments, organic pigments, etc., excluding salts, can be appropriately blended within a range not impairing the effects of the present invention.
The cleaning material can be produced by a normal method, and the dosage form can be any dosage form such as liquid, paste, solid, powder, etc., but in particular liquid or paste Is preferred.

Unless otherwise specified,% in the examples is mass%. Further, ion-exchanged water was used unless otherwise specified.
<Measurement of crystallization index of cellulose>
Using a “Rigaku RINT 2500VC X-RAY diffract meter” manufactured by Rigaku Corporation, the crystallization index of cellulose was calculated from the peak intensity of the diffraction spectrum measured under the following conditions by the above formula (1).
X-ray light source: Cu / Kα-radiation,
Tube voltage: 40 kV, tube current: 120 mA
Measurement range: 2θ = 5-45 °,
Measurement sample: Prepared by compressing pellets with an area of 320 mm ² × thickness 1 mm X-ray scanning speed: 10 ° / min

<Measurement of average molecular weight>
[Measurement of weight average molecular weight of C-PU and cationized carboxymethyl cellulose]
C-PU (A) obtained in Example 1, C-PU (B) obtained in Example 2, C-PU (C) obtained in Example 3, and obtained in Comparative Example 1 The weight average molecular weight (Mw) of cationized carboxymethyl cellulose (hereinafter referred to as “C-CMC”) was measured by gel permeation chromatography (GPC) under the following conditions.
〔sample〕
0.5g / 100mL (eluent), 20μL
[Measurement equipment and measurement conditions]
Eluent channel pump; manufactured by Hitachi, Ltd., trade name: L-6000,
Detector: Differential refractive index detector (manufactured by Showa Denko KK, trade name: SHODEX RI SE-61) Column temperature: 40 ° C
Flow rate: 1.0 ml / min Column: TSKgel G400PWXL, G2500 manufactured by Tosoh Corporation
Eluent: 0.2M phosphate buffer / acetonitrile = 9/1 (mass ratio)
Standard polymer: Pullulan (trade name SHODEX STD-P5, STD-P50, STD-P200, STD-P800, manufactured by Showa Denko KK)

(Measurement of weight average molecular weight of cationized hydroxyethyl cellulose)
The weight average molecular weight of the cationized hydroxyethyl cellulose (trade name; Poise C-80M, hereinafter referred to as “C-HEC”) used in Comparative Example 3 was measured using the following column and eluent. Except for the above, it was carried out in the same manner as described in the section of measuring the weight average molecular weight of C-PU.
Column: Two TSKgel α-Ms manufactured by Tosoh Corporation were connected in series.
Eluent: A solution obtained by dissolving Na ₂ SO ₄ in a 1% aqueous acetic acid solution to a concentration of 0.15 mol / L was used.

[Measurement of viscosity average molecular weight of cellulose (copper-ammonia method)]
(I) Preparation of solution for measurement After adding 0.5 g of cuprous chloride and 20-30 mL of 25% aqueous ammonia to a measuring flask (100 mL) and completely dissolving, 1.0 g of cupric hydroxide and 25% Ammonia water was added to make an amount just before the marked line. This was stirred for 30-40 minutes to completely dissolve. Thereafter, precisely weighed cellulose was added to fill the ammonia water up to the marked line. It sealed so that air might not enter, and it stirred and melt | dissolved with the magnetic stirrer for 12 hours, and prepared the solution for a measurement. The amount of cellulose to be added was changed in the range of 20 to 500 mg to prepare measurement solutions having different concentrations.
(Ii) Measurement of viscosity average molecular weight The solution for measurement (copper ammonia solution) obtained in (i) above was placed in an Ubbelohde viscometer and allowed to stand in a thermostatic bath (20 ± 0.1 ° C.) for 1 hour. The flow rate of the liquid was measured. From the flow time [t (second)] of the copper ammonia solution having various cellulose concentrations (g / dL) and the flow time [t ₀ (second)] of the aqueous solution of copper ammonia without addition of cellulose, The reduced viscosity (ηsp / c) was determined by the following formula.
η _sp / c = (t / t ₀ −1) / c
(Where c is the cellulose concentration (g / dL))
Further, the intrinsic viscosity [η] (dL / g) was obtained by extrapolating the reduced viscosity to c = 0, and the viscosity average molecular weight (M _vis ) was obtained by the following formula.
M _vis = 2000 × [η] × 162
(In the formula, 2000 is a coefficient specific to cellulose, and 162 is the molecular weight of anhydroglucose which is a constituent sugar residue of cellulose.)

(Calculation method of average degree of substitution of cationic groups and average degree of substitution of carboxyl groups)
The average substitution degree of the cationic group and the average substitution degree of the carboxyl group of the polymer were calculated as follows. That is, it was calculated by the following simultaneous equations from the nitrogen content and carboxylic acid content of the polymer measured by the following method.
(1) Average degree of substitution of cationic groups Average degree of substitution of cationic groups of C-PU (A) or C-PU (B) = (162 + 36 × x) × Y / (2800-54 × Y)
Average substitution degree of cationic group of C-PU (C) = (162 + 80 × x) × Y / (2800-151 × Y)
(In the formula, Y is the nitrogen content (%), and x is the degree of carboxyl group substitution.)
(2) Average degree of substitution of carboxyl group Average degree of substitution of carboxyl group of C-PU (A) or (B) = (162 + 54 × y) × X / (1-36 × X)
Average substitution degree of carboxyl group of C-PU (C) = (162 × X + 151 × y) / (1-80 × X)
Average degree of substitution of carboxyl group of polyuronic acid = 162 × X / (1-14 × X)
(In the formula, X is the amount of carboxylic acid (mol / g) determined by titration, and y is the degree of cationic group substitution.)

(Measurement of nitrogen content)
The nitrogen content (%) of C-PU was measured according to Kjeldahl analysis method (“Reagent Test Method General Nitrogen Compound” JIS K 8001).

(Measurement of carboxylic acid content)
The amount of carboxylic acid in C-PU was determined as follows. That is, 50 g of a 2% aqueous solution of the sample was prepared, and the pH was adjusted to 1 or less with 6N hydrochloric acid. This acidic solution was poured into 500 mL of ethanol, and the resulting precipitate was collected and dried under reduced pressure at 40 ° C. overnight. 0.1 g of the obtained sample is precisely weighed, dissolved or dispersed in 30 mL of ion exchange water, titrated with 0.1N aqueous sodium hydroxide solution using phenolphthalein as an indicator, and the amount of carboxylic acid per unit weight (mol / g). )

Example 1 (Synthesis of C-PU (A))
Cellulose powder (trade name: KC Flock W-400G manufactured by Nippon Paper Chemical Co., Ltd.) was dried at 105 ° C. for 3 hours. An operation of pulverizing 25 g of the obtained cellulose powder with a planetary ball mill (trade name: P-6, manufactured by Fritsch) for 10 minutes (rotation speed: 400 rpm) and allowing to stand for 10 minutes was repeated 12 times to obtain low crystalline cellulose. A powder (crystallinity 0%, viscosity average molecular weight 30000) was obtained.
In a 1 L beaker equipped with a pH meter, 0.39 g of 2,2,6,6-tetramethylpiperidine-1-oxyl (trade name: TEMPO, manufactured by Aldrich), 580 g of water, and the low crystalline property obtained above. 20 g of cellulose powder (crystallinity 0%, constituent sugar residue 0.12 mol) was added, and the mixture was stirred at 200 rpm using a stirrer. While maintaining the temperature at around 20 ° C., 180 g (0.27 mol) of an 11% aqueous sodium hypochlorite solution (manufactured by Wako Pure Chemical Industries, Ltd.) was gradually added using a microtube pump. Since the pH decreased as the oxidation reaction proceeded, a 1.0N aqueous sodium hydroxide solution was added dropwise to keep the pH of the solution around 8.5. The reaction mixture was almost uniform and transparent at the stage where the addition of the sodium hypochlorite aqueous solution and the sodium hydroxide aqueous solution was completed.
The reaction was terminated after 3 hours, and the resulting reaction mixture was poured into 7 L of ethanol to precipitate a white solid. The precipitate was dissolved again in 1 L of water, and the water-insoluble matter was separated by filtration. Then, the water-soluble matter was poured into 7 L of acetone to precipitate a white solid. By drying under reduced pressure at 40 ° C. and −80 kPaG overnight, 22 g of a white solid was obtained. The substitution degree of the carboxyl group of the obtained polyuronic acid was 0.8.
In a 300 mL beaker equipped with a pH meter, 5.0 g of the white solid obtained above (constituting sugar residue 0.026 mol) was dissolved in 40 g of water. To this solution, 1.3 g (0.013 mol) of N, N-dimethyl-1,3-propanediamine (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and then the pH was adjusted to 3 by adding 1.0 N hydrochloric acid. did. Thereafter, 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorpholinium chloride n hydrate (manufactured by Wako Pure Chemical Industries, Ltd.) previously dissolved in 20 g of water. 4.4 g was added and stirred at room temperature for 3 hours. The resulting solution was dialyzed using a dialysis membrane in water maintained at pH 3 for 2 days. The dialysis membrane used was a Visking tube 28.6 mm (manufactured by AS ONE Co., Ltd., pore diameter 50 mm), and the water was changed three times a day. After the dialysis operation was completed, a 1.0 N aqueous sodium hydroxide solution was added dropwise to adjust the pH to around 7. The obtained solution was freeze-dried to obtain 4.8 g of white C-PU (A).
The obtained C-PU (A) had a weight average molecular weight of 23,000, a nitrogen content of 2.2%, a carboxylic acid amount of 0.0033 mol / g, and an average degree of substitution of the cationic group of 0.2. The average degree of substitution of the carboxyl group was 0.7.

Example 2 (Synthesis of C-PU (B))
The amount of N, N-dimethyl-1,3-propanediamine was changed to 2.6 g (0.025 mol), and 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) -4- The same operation as in Example 1 was carried out except that the amount of methylmorpholinium chloride n hydrate was changed to 8.9 g, to obtain 4.8 g of white C-PU (B).
The obtained C-PU (B) had a weight average molecular weight of 22,000, a nitrogen content of 4.1%, a carboxylic acid amount of 0.0023 mol / g, and an average degree of substitution of the cationic group of 0.3%. The average degree of substitution of carboxyl groups was 0.4.

Example 3 (Synthesis of C-PU (C))
Add 250g of water to 20g of cellulose powder (KC Flock W-400G manufactured by Nippon Paper Chemical Co., Ltd., viscosity average molecular weight 30000) (constituent sugar residue 0.12 mol), and leave it for 30 minutes to make cellulose powder. Swelled. Thereafter, water was filtered through a glass filter, and 100 mL of N, N-dimethylacetamide (manufactured by Wako Pure Chemical Industries, Ltd.) was added, followed by filtration three times. In a 2 L three-necked flask equipped with a stirrer and a Dimroth refluxer, swollen cellulose powder, 100 g of lithium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) and 1200 g of N, N-dimethylacetamide were added. After nitrogen substitution, the reaction solution was heated to 100 ° C., held for 1 hour, and then cooled to room temperature. The reaction solution was again heated to 100 ° C., held for 1 hour, cooled to room temperature, then added with 490 g of N, N-dimethylacetamide, again heated to 100 ° C., held for 1 hour, cooled to room temperature. Was repeated.
In a 2 L three-necked flask equipped with a stirrer and a Dimroth refluxer, 1500 g of the above cellulose solution was added, the temperature was raised to 110 ° C., and the mixture was allowed to cool to room temperature. 2.6 g of t-butoxy potassium (manufactured by Wako Pure Chemical Industries, Ltd.) was added, the temperature was raised again to 110 ° C., and 50 g (0.27 mol) of an 80% aqueous solution of glycidyltrimethylammonium chloride (manufactured by Sakamoto Pharmaceutical Co., Ltd.) was added. The solution was added dropwise and stirred for 3 hours.
After completion of the reaction, the reaction mixture was poured into 4 L of ethanol to precipitate a yellow solid. The precipitate was dissolved again in 1 L of water, and dialysis was performed using a dialysis membrane in water maintained at pH 7. In addition, a Visking tube 28.6 mm (manufactured by ASONE Co., Ltd., pore diameter 50 mm) was used as a dialysis membrane, and water was changed three times a day during dialysis. After completing the dialysis operation, the resulting solution was freeze-dried to obtain 8.7 g of a yellow solid.

In a 500 mL beaker equipped with a pH meter, 2,2,6,6-tetramethylpiperidine-1-oxyl 0.02 g, water 240 g, the yellow solid obtained above 5.0 g (constituting sugar residue 0.024 mol) And stirred at 200 rpm using a stir bar. While maintaining the temperature at around 20 ° C., 26 g (0.038 mol) of an 11% aqueous sodium hypochlorite solution was gradually added using a microtube pump. Since the pH decreased as the oxidation reaction proceeded, a 1.0N aqueous sodium hydroxide solution was added dropwise to keep the pH of the solution around 8.5.
The resulting solution was dialyzed using a dialysis membrane in water maintained at pH 3 for 2 days. In addition, a Visking tube 28.6 mm (manufactured by ASONE Co., Ltd., pore diameter 50 mm) was used as a dialysis membrane, and water was changed three times a day during dialysis. After the dialysis operation was completed, a 1.0 N aqueous sodium hydroxide solution was added dropwise to adjust the pH to around 7. The obtained solution was freeze-dried to obtain 3.4 g of white C-PU (C).
The obtained C-PU (C) had a weight average molecular weight of 13,000, a nitrogen content of 3.2%, a carboxylic acid amount of 0.0032 mol / g, and an average degree of substitution of the cationic group of 0.3. The average substitution degree of the carboxyl group was 0.7.

Comparative Example 1 (Synthesis of C-CMC)
C-CMC was synthesized according to the synthesis example described in Patent Document 2. Specifically, carboxymethyl cellulose (manufactured by Nippon Paper Chemical Co., Ltd., trade name: FT-1, average substitution degree of carboxyl group; 0.9), 5.0 g (constituting sugar residue 0.023 mol) in a 300 mL beaker. Dissolved in 100 g of water. 68 g of 1.0N sodium hydroxide aqueous solution was added and stirred, and then transferred to a 300 mL three-necked flask equipped with a stirrer and a Dimroth reflux device. 7. The temperature of the reaction solution is increased to 45 ° C., and a 50% aqueous solution of glycidyltrimethylammonium chloride chloride (adjusted to 50% by adding water to an 80% aqueous glycidyltrimethylammonium chloride chloride solution manufactured by Sakamoto Yakuhin Co., Ltd.) 6 g (0.046 mol) was added dropwise, and the mixture was stirred at 50 ° C. for 2 hours. The resulting solution was dialyzed using a dialysis membrane in water maintained at pH 3 for 2 days. In addition, a Visking tube 28.6 mm (manufactured by ASONE Co., Ltd., pore diameter 50 mm) was used as a dialysis membrane, and water was changed three times a day during dialysis. After the dialysis operation was completed, a 1.0 N aqueous sodium hydroxide solution was added dropwise to adjust the pH to around 7. The obtained solution was freeze-dried to obtain 3.5 g of white C-CMC.
The weight average molecular weight of the obtained C-CMC was 26,000, the average degree of substitution of the cationic group determined according to the method for measuring the average degree of substitution of the cationic group of C-PU and the average degree of substitution of the carboxyl group. Was 0.1, and the average degree of substitution of the carboxyl group was 0.9.

Examples 4-6, Comparative Examples 2-3
As polymers shown in Table 2, C-PU (A) obtained in Example 1 (Example 4), C-PU (B) obtained in Example 2 (Example 5), and Comparative Example 1 The obtained C-CMC (Comparative Example 2) and a commercially available feel improver [cationized hydroxyethyl cellulose (C-HEC), manufactured by Kao Corporation, trade name; Poise C-80M, average substitution degree of cationic group 0 .1] Using (Comparative Example 3), hair treatments A to E having the compositions shown in Table 2 were produced by a conventional method.
About the obtained sample, the smoothness at the time of rinse and the firmness of the hair after drying were evaluated by the following evaluation methods by four panelists. For each, an average score was determined. The results are shown in Table 3.
(Evaluation method)
(1) Rinsing performance: 1 g of hair treatment was applied to 20 g of hair traces, and the feel of the smoothness of the hair when rinsed with running water for 30 seconds was subjected to sensory evaluation based on the following criteria.
(2) Drying performance: When the hair traces rinsed in (1) were dried with a dryer, the firmness of the hair was subjected to sensory evaluation based on the following criteria.
<Evaluation criteria>
The conditioner to which no polymer was added was rated as 3, and was evaluated in five stages.
5; Good. 4; Slightly good. 3: Normal. 2; Somewhat bad. 1; bad.

  As is apparent from Table 3, the cation-modified polyuronic acid of the present invention remarkably improved the “deterioration of smoothness during rinsing”, which was a problem with conventional feel-imparting agents, while imparting firmness to the hair after drying. ing.

  The cation-modified polyuronic acid or a salt thereof of the present invention has an excellent feeling improving effect. The touch-improving agent having the cation-modified polyuronic acid or a salt thereof as an active ingredient can achieve both smoothness at the time of rinsing and improvement of hair elasticity after drying, and hair for shampoo, hair rinse, hair conditioner, hair treatment, etc. It can be applied to cosmetics.

Claims (9)

A cation-modified polyuronic acid or a salt thereof having a structure in which a cationic group represented by the following general formula (1) is introduced into polyuronic acid.

(In the formula, A represents a divalent hydrocarbon group having 1 to 6 carbon atoms which may be substituted with a hydroxyl group. R ¹ and R ² are the same or different and each represents a hydrocarbon group having 1 to 3 carbon atoms. R ³ represents a hydrocarbon group having 1 to ³ carbon atoms or a hydrogen atom, and Z ⁻ represents a monovalent anion.)   The cation-modified polyuronic acid or a salt thereof according to claim 1, wherein the polyuronic acid is polyuronic acid obtained by oxidizing cellulose.   The cation-modified polyuronic acid or a salt thereof according to claim 1 or 2, having a weight average molecular weight of 5,000 to 500,000. The cation-modified polyuronic acid or a salt thereof according to any one of claims 1 to 3, wherein the cation-modified polyuronic acid is represented by the following general formula (2).

(Wherein X is the same or different and represents a cationic group or a hydrogen atom represented by the general formula (1), and in the molecule, at least one of X is a cationic group represented by the general formula (1). Q is a nitrogen atom substituted with an alkyl group having 1 to 3 carbon atoms, a nitrogen atom to which a hydrogen atom is bonded, an atom selected from the group consisting of an oxygen atom and a sulfur atom, or a functional group, When the bonded X is a hydrogen atom, Q is an oxygen atom, and m and n each represent the average degree of polymerization of the constituent monosaccharide residues in parentheses.)   The average substitution degree per constituent monosaccharide residue of the cationic group represented by the general formula (1) is 0.1 to 0.7, and the average per constituent monosaccharide residue of the carboxyl group or a salt thereof The cation-modified polyuronic acid or a salt thereof according to any one of claims 1 to 4, wherein the substitution degree is 0.3 to 1.0.   A feel improving agent having the cation-modified polyuronic acid or a salt thereof according to any one of claims 1 to 5 as an active ingredient.   The feel-improving agent according to claim 6, which is used for hair cosmetics. A method for producing cation-modified polyuronic acid or a salt thereof, which comprises oxidizing cellulose and then reacting with a cationizing agent represented by the following general formula (3).

Wherein Y is an atom or a functional group selected from the group consisting of an epoxy group, a halogen atom, a primary or secondary amino group, a hydroxyl group, and a thiol group, and A ′ is substituted with a hydroxyl group. Or a divalent hydrocarbon group having 1 to 6 carbon atoms, provided that when Y is an epoxy group, A ′ represents a divalent hydrocarbon group having 1 to 4 carbon atoms, R ^{1 to} R ³ , And Z ⁻ have the same meaning as in the general formula (1).)   A method for producing a cation-modified polyuronic acid or a salt thereof, which comprises reacting cellulose with a cationizing agent represented by the general formula (3), followed by oxidation.