JP7657776B2 - Cation-modified diutan gum with excellent dispersion stability - Google Patents

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No. 2020-054131, the entire disclosure of which is incorporated herein by reference.

The present invention relates to polysaccharides, and more specifically to cationically modified diutan gum.

Traditionally, polysaccharides have been used to improve the quality of various products such as food, cosmetics, and industrial products. Examples of such polysaccharides include natural polysaccharides such as xanthan gum, tamarind gum, and fenugreek gum.

Furthermore, in Patent Documents 1 to 4, in order to improve the functionality of polysaccharides, cationically modified polysaccharides are proposed in which some of the hydroxyl groups are replaced with quaternary nitrogen-containing groups. It is also described that when cationically modified polysaccharides are contained in shampoos and the like, the conditioning properties are improved, such as suppressing squeaking when washing hair.

In addition, in liquid compositions containing insoluble solid particles, polysaccharides may be used to uniformly disperse the solid particles in the liquid composition. For example, in the case of a cosmetic composition, polysaccharides may be used to uniformly disperse the scrubbing agent as the solid particles in the cosmetic composition. Furthermore, when the liquid composition is an emulsion composition, polysaccharides may be used to uniformly disperse the emulsion particles in the composition.

Japan Special Publication No. 47-20635 Japanese Patent No. 4716110 Japanese Patent Application Publication No. 2007-63446 Japanese Patent Application Publication No. 2012-1676

However, when using conventional polysaccharides, it may be difficult to stably and uniformly disperse the solid particles or emulsified particles in the liquid composition, for example, the solid particles may float to the liquid surface or precipitate.
Furthermore, when the liquid composition is an emulsion composition, phase separation may occur between the oil component and water, and emulsion particles may not be uniformly dispersed.
Therefore, there is a continuing demand for polysaccharides that can improve the dispersion stability of the liquid composition.

Under these circumstances, the present inventors conducted intensive research and discovered that cation-modified diutan gum, obtained by cationically modifying a polysaccharide called diutan gum, improves the dispersion stability of the liquid composition when the cationic charge amount is adjusted to a specific amount.

In other words, the objective of the present invention is to provide a cation-modified diutan gum that has excellent properties in improving the dispersion stability of a liquid composition.

（式中Ｒ^１及びＲ^２は炭素数１～３のアルキル基であり、Ｒ^３は炭素数１～２４のアルキル基であり、Ｒ^４及びＲ^５は炭素数１～３のアルキル基又は水素原子であり、Ｘ^－は１価の陰イオンを示す） The cation-modified diutan gum according to the present invention is
A cation-modified diutan gum in which a part of the hydroxyl groups is substituted with a quaternary nitrogen-containing group represented by chemical formula (1),
The amount of cationic charge derived from the quaternary nitrogen-containing group is 0.3 to 0.8 meq/g.

(wherein ^R1 and ^R2 are alkyl groups having 1 to 3 carbon atoms, ^R3 is an alkyl group having 1 to 24 carbon atoms, ^R4 and ^R5 are alkyl groups having 1 to 3 carbon atoms or a hydrogen atom, and ^X- represents a monovalent anion.)

The cationically modified diutan gum according to the present invention preferably comprises:
^R4 and ^R5 are hydrogen atoms.

The cationically modified diutan gum according to the present invention preferably comprises:
^R3 is an alkyl group having 1 to 3 carbon atoms.

The cationically modified diutan gum according to the present invention preferably comprises:
R ¹ , R ² and R ³ are methyl groups.

The dispersion stabilizer of the present invention also contains the above-mentioned cation-modified diutan gum.

The cosmetic composition of the present invention also contains the above-mentioned cation-modified diutan gum.

FIG. 1 compares the IR spectra of the cationically modified diutan gum of Example 2 (solid line) and the unmodified diutan gum of Comparative Example 3 (dashed line).

Below, we will explain one embodiment of the cation-modified diutan gum.

In order to exert its function, the cation-modified diutan gum of this embodiment is preferably used by being contained in a liquid composition. The liquid composition is composed of a dispersion liquid in which solid particles are dispersed, and contains the cation-modified diutan gum dissolved in the dispersion medium of the dispersion liquid. By containing the cation-modified diutan gum in the liquid composition, the solid particles can be stably and uniformly dispersed in the liquid composition.
The dispersion medium may be an emulsion containing an oil component and water. In other words, the liquid composition may be an emulsion composition. In this case, the liquid composition contains the cation-modified diutan gum, so that the emulsion particles contained therein become minute and are stably and uniformly dispersed.
In this specification, the degree to which the solid particles and/or the emulsified particles are uniformly and stably dispersed in the liquid composition is sometimes referred to as dispersion stability.

When the cation-modified diutan gum is contained in the liquid composition containing the solid particles, it is preferable that the aqueous solution containing the cation-modified diutan gum has a specific viscosity. Specifically, the viscosity (at 25° C.) of an aqueous solution of the cation-modified diutan gum having a concentration of 0.25% by mass is preferably 10,000 to 100,000 mPa·s, and more preferably 30,000 to 60,000 mPa·s, at a shear rate of 0.01 s ⁻¹ . This allows the solid particles to be uniformly dispersed in the liquid composition.
The viscosity is a value measured by the method described in the examples.

When the liquid composition is an emulsion composition, the emulsion composition may be of the oil-in-water (O/W) type or the water-in-oil (W/O) type.
The emulsion particle size (median size) is preferably 50 μm or less, and more preferably 40 μm or less, which can improve the emulsion stability of the emulsion composition.
The emulsion particle size refers to a value measured by the measurement method described in the Examples.

The cation-modified diutan gum according to this embodiment is a cation-modified diutan gum in which a part of the hydroxyl groups contained in the diutan gum is substituted with a quaternary nitrogen-containing group represented by chemical formula (1). As a result, the cation-modified diutan gum has a cationic charge.

The diutan gum is a polysaccharide that accumulates outside the cells of the genus Alcaligenes during the fermentation process. The repeating units of the diutan gum have a main chain composed of glucose, glucuronic acid, glucose, and rhamnose, and a side chain composed of rhamnose disaccharide. In other words, the diutan gum is an anionic polysaccharide having repeating units of these 6 sugars. Commercially available diutan gum can be used. Examples of the commercially available diutan gum include KELCO-VIS DG (manufactured by CP Kelco U.S., Inc.).

In the above chemical formula (1), ^R1 and ^R2 represent an alkyl group having 1 to 3 carbon atoms. Examples of ^R1 and ^R2 include a methyl group, an ethyl group, and a propyl group, and among these, a methyl group is preferable. Furthermore, ^R1 and ^R2 are preferably the same type of functional group. The propyl group may be an n-propyl group or an iso-propyl group.

Furthermore, ^R3 represents an alkyl group having 1 to 24 carbon atoms. Examples of ^R3 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group. Among these, a methyl group or an ethyl group is preferable, and a methyl group is more preferable. Furthermore, ^R3 is preferably the same type of functional group as ^R1 and ^R2 . These alkyl groups may be linear, branched, or cyclic.

Furthermore, ^R4 and ^R5 represent an alkyl group having 1 to 3 carbon atoms or a hydrogen atom. In the case of an alkyl group, ^R4 and ^R5 include a methyl group, an ethyl group, and a propyl group. ^R4 and ^R5 are preferably a methyl group or a hydrogen atom, and more preferably a hydrogen atom. The propyl group may be an n-propyl group or an iso-propyl group.

X ⁻ represents a monovalent anion. Examples of X ⁻ include halide ions such as chloride ion, bromide ion, and iodide ion, methyl sulfate ion, and ethyl sulfate ion. Among these, halide ions are preferred, and chloride ions are more preferred.

The cation-modified diutan gum is synthesized by reacting the diutan gum with a glycidyl trialkyl ammonium salt or a 3-halogeno-2-hydroxypropyl trialkyl ammonium salt having the corresponding structure. In this case, the reaction is carried out in a suitable solvent, preferably an aqueous alcohol, in the presence of an alkali. The introduction of such a quaternary nitrogen-containing group can be carried out according to a conventionally known method, but is not necessarily limited to these.

It is important that the cationic charge amount of the cation-modified diutan gum is 0.3 to 0.8 meq/g, preferably 0.30 to 0.85 meq/g, more preferably 0.44 to 0.7 meq/g, and even more preferably 0.44 to 0.62 meq/g. When the cationic charge amount is within the above numerical range, the dispersion stability of the liquid composition becomes excellent. In addition, the spinnability of the liquid composition is reduced, improving the workability when filling the liquid composition into a container or the like.

The cationic charge amount means the number of equivalents of the nitrogen content derived from the quaternary nitrogen-containing group contained in 1 g of the cation-modified diutan gum. In other words, the cationic charge amount means a value calculated by the following formula (1). The nitrogen content derived from the quaternary nitrogen-containing group in formula (1) means a value measured by the Kjeldahl method (old cosmetic raw material standard, general test method, nitrogen determination method, method 2).
Since the diutan gum usually contains nitrogen derived from proteins, it is necessary to remove the nitrogen derived from proteins when measuring the nitrogen content of the cationically modified diutan gum. That is, the nitrogen content derived from the quaternary nitrogen-containing group in the cationically modified diutan gum measured by the Kjeldahl method is calculated by subtracting the measured value of the nitrogen content of the diutan gum before cation modification from the measured value of the nitrogen content of the diutan gum after cation modification.
This will be specifically explained using the measurement examples of Example 2 and Comparative Example 3 shown in Table 1. The measured nitrogen content of the cation-modified diutan gum (Example 2) was 1.66%, and the measured nitrogen content of the diutan gum before cation modification (Comparative Example 3) was 0.88%, so when these measured values are substituted into the following formula (1), the cationic charge amount of the cation-modified diutan gum of Example 2 is calculated to be 0.557 (meq/g).

In addition to the difference in cationic charge, the cation-modified diutan gum of this embodiment also exhibits an IR spectrum different from that of the diutan gum (FIG. 1). Specifically, the IR spectrum of the cation-modified diutan gum shows a decrease in peak intensity (peak height) for some peaks compared to the IR spectrum of the diutan gum. In particular, a significant decrease in peak intensity is observed for the first peak P1 near 1730 cm ^-1 . On the other hand, no significant decrease in peak intensity is observed for the second peak P2 near 1600 cm ^-1 adjacent to the first peak P1.
That is, the cationically modified diutan gum has a ratio of the peak intensity of the first peak P1 to the peak intensity of the second peak P2 in an IR spectrum of 0.1 to 0.4. In contrast, the diutan gum has a ratio of the peak intensity of the first peak P1 to the peak intensity of the second peak P2 in an IR spectrum of 0.5 to 1.0. Thus, the cationically modified diutan gum has a smaller ratio than the diutan gum.
The IR spectrum is measured by the method described in the Examples, and the peak intensity ratio is a value calculated by the method described in the Examples.

The cation-modified diutan gum of this embodiment can be used as a dispersion stabilizer to impart excellent dispersion stability to the liquid composition described above. The dispersion stabilizer can be suitably used in products such as food, cosmetics, and industrial products that contain the solid particles and/or the emulsion particles.

The dosage form of the dispersion stabilizer is not particularly limited, and may be a solid such as a powder or granules, or a liquid such as an aqueous solution. When the dispersion stabilizer is a solid, the content of the cation-modified diutan gum relative to the total mass of the dispersion stabilizer is typically 0.1 to 100% by mass. When the dispersion stabilizer is a liquid, the concentration of the cation-modified diutan gum in the dispersion stabilizer is typically 0.1 to 10% by mass.

The dispersion stabilizer may contain additives other than the cation-modified diutan gum, so long as they can perform their functions. Examples of the additives include thickeners such as xanthan gum and locust bean gum, lubricants such as magnesium stearate, metal salts such as sodium chloride and potassium chloride, and dispersants (viscosity adjusters) such as glucose and dextrin.

The liquid composition is preferably a cosmetic composition containing the cation-modified diutan gum. The formulation of the cosmetic composition is not particularly limited, and any formulation can be adopted. Specific formulations include lotion, milky lotion, beauty serum, gel, cream, facial cleanser, oil-in-lotion, sunscreen, shampoo, treatment, body soap, etc. Among these applications, the cosmetic composition is preferably used in cleansing agents such as facial cleanser, shampoo, and body soap. In other words, the cosmetic composition is preferably a cleansing cosmetic composition used in facial cleanser, shampoo, body soap, etc.

The content of the cation-modified diutan gum relative to the total mass of the cosmetic composition is usually 0.05 to 5 mass%, and more preferably 0.1 to 3 mass%. This provides the cosmetic composition with excellent dispersion stability, suppresses the sticky and tacky sensation during use, and provides a good feel when used.

The density of the liquid component contained in the cosmetic composition is typically 0.70 to 1.30 (g/mL).

The oily component that may be contained in the cosmetic composition is preferably an oily component that is easily compatible with hair, skin, nails, etc. Examples of such oily components include fatty acids, fatty acid esters, hydrocarbon oils, and silicone oils.

The fatty acid is preferably a fatty acid having 8 to 22 carbon atoms, more preferably a fatty acid having 12 to 18 carbon atoms, and even more preferably a fatty acid having 16 to 18 carbon atoms. Examples of fatty acids with such carbon numbers include caprylic acid (8 carbon atoms), undecylenic acid (11 carbon atoms), capric acid (10 carbon atoms), lauric acid (12 carbon atoms), myristic acid (14 carbon atoms), palmitic acid (16 carbon atoms), stearic acid (18 carbon atoms), linoleic acid (18 carbon atoms), linolenic acid (18 carbon atoms), isostearic acid (18 carbon atoms), oleic acid (18 carbon atoms), eicosapentaenoic acid (20 carbon atoms), behenic acid (22 carbon atoms), and docosahexaenoic acid (22 carbon atoms).

The fatty acid ester is preferably a fatty acid ester having 12 to 54 carbon atoms, more preferably a fatty acid ester having 14 to 50 carbon atoms, and even more preferably a fatty acid ester having 16 to 46 carbon atoms. Examples of the fatty acid ester having such a carbon number include cetyl octanoate (carbon number 24), ethyl laurate (carbon number 14), hexyl laurate (carbon number 18), isopropyl myristate (carbon number 17), octyldodecyl myristate (carbon number 34), myristyl myristate (carbon number 28), 2-hexyldecyl myristate (carbon number 30), glycerin trimyristate (carbon number 45), isopropyl palmitate (carbon number 19), palmitate (carbon number 20), and glyceryl trimethacrylate (carbon number 21). 2-Ethylhexyl palmitate (carbon number 24), 2-heptylundecyl palmitate (carbon number 36), 2-hexyldecyl palmitate (carbon number 34), butyl stearate (carbon number 22), isocetyl stearate (carbon number 34), isocetyl isostearate (carbon number 34), cholesteryl 12-hydroxystearate (carbon number 45), trimethylolpropane triisostearate (carbon number 54), decyl oleate (carbon number 2 8), cetyl lactate (carbon number 19), myristyl lactate (carbon number 17), cetyl 2-ethylhexanoate (carbon number 24), ethylene glycol di-2-ethylhexyl acid (carbon number 22), trimethylolpropane tri-2-ethylhexyl acid (carbon number 30), glycerin tri-2-ethylhexyl acid (carbon number 27), pentaerythritol tetra-2-ethylhexyl acid (carbon number 37), cetyl 2-ethylhexanoate (carbon number 24), adipine diisobutyl adipate (number of carbons: 14), 2-heptylundecyl adipate (number of carbons: 42), 2-hexyldecyl adipate (number of carbons: 38), neopentyl glycol dicaprate (number of carbons: 25), diisostearyl malate (number of carbons: 40), di-2-ethylhexyl sebacate (number of carbons: 26), diisopropyl sebacate (number of carbons: 16), 2-ethylhexyl succinate (number of carbons: 20), and triethyl citrate (number of carbons: 12).

As the oil component containing a plurality of the fatty acids and/or fatty acid esters, a natural oil component can be used. Examples of the natural oil component include olive oil, jojoba oil, castor oil, mink oil, tall oil, coconut oil, and palm oil.

Examples of the hydrocarbon oil include liquid paraffin, squalane, α-olefin oligomer, and petrolatum.

Examples of the silicone oil include low- to high-viscosity linear or branched organopolysiloxanes such as dimethylpolysiloxane, tristrimethylsiloxymethylsilane, caprylyl methicone, phenyl trimethicone, tetrakistrimethylsiloxysilane, methylphenylpolysiloxane, methylhexylpolysiloxane, methylhydrogenpolysiloxane, and dimethylsiloxane-methylphenylsiloxane copolymers, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, tetramethyltetrahydrogencyclotetrasiloxane, and tetramethyltetraphenylcyclotetrasiloxane. Examples of the silicone rubber include cyclic organopolysiloxanes such as tetrasiloxane, amino-modified organopolysiloxanes, pyrrolidone-modified organopolysiloxanes, pyrrolidone carboxylic acid-modified organopolysiloxanes, gum-like dimethylpolysiloxanes with a high degree of polymerization, gum-like amino-modified organopolysiloxanes, and gum-like dimethylsiloxane-methylphenylsiloxane copolymers, as well as cyclic organopolysiloxane solutions of silicone gums and rubbers, higher alkoxy-modified silicones such as stearoxysilicone, higher fatty acid-modified silicones, alkyl-modified silicones, long-chain alkyl-modified silicones, amino acid-modified silicones, and fluorine-modified silicones.

The content of the oily component is usually 0.1 to 90% by mass, and preferably 4 to 40% by mass, based on the total mass of the cosmetic composition. The content of the water is usually 10 to 99% by mass, and preferably 50 to 95% by mass, based on the total mass of the cosmetic composition.

The solid particles include low-specific gravity solid particles having a specific gravity of less than 1 relative to the liquid component, and high-specific gravity solid particles having a specific gravity of 1 or more relative to the liquid component. The specific gravity of the low-specific gravity solid particles is preferably 0.01 to 0.99, and more preferably 0.20 to 0.95. The specific gravity of the high-specific gravity solid particles is preferably 1.01 to 20, and more preferably 1.05 to 10, and even more preferably 1.05 to 1.25.

The solid particles that may be contained in the cosmetic composition may be organic solid particles or inorganic solid particles.

Examples of the organic solid particles include solid fats such as solid paraffin, ceresin, synthetic wax, and carnauba wax; polyesters such as polylactic acid, polyhydroxybutyric acid, and polyacrylic acid/acrylic acid esters; polyamides such as nylon; polyethylene, polypropylene, polyurethane, vinyl resins, tetrafluoroethylene, polymethyl methacrylate, cellulose, silk, and polymer particles such as polymethylsilsesquioxane.

Examples of the inorganic solid particles include particles of magnesium oxide, barium sulfate, calcium sulfate, magnesium sulfate, calcium carbonate, magnesium carbonate, talc, mica, kaolin, sericite, silica, aluminum silicate, magnesium silicate, aluminum magnesium silicate, calcium silicate, hydroxyapatite, zeolite, secondary calcium phosphate, alumina, aluminum hydroxide, and boron nitride.
When the inorganic solid component is an ultraviolet scattering agent, examples of the agent include zinc oxide, zirconium oxide, and titanium oxide.
Furthermore, when the inorganic solid component is a pigment, examples of the inorganic solid component include inorganic red pigments such as iron oxide and iron titanate, inorganic brown pigments such as γ-iron oxide, inorganic yellow pigments such as yellow iron oxide and ocher, inorganic black pigments such as black iron oxide and carbon black, inorganic purple pigments such as manganese violet and cobalt violet, inorganic green pigments such as chromium hydroxide, chromium oxide, cobalt oxide and cobalt titanate, inorganic blue pigments such as iron blue and ultramarine, white pigments such as titanium mica, pigment-coated titanium mica and titanium oxide, and pearl pigments such as synthetic phlogopite.

The content of the solid particles is typically 0.1 to 50% by mass, and preferably 0.5 to 30% by mass, relative to the total mass of the cosmetic composition.

The cosmetic composition may contain a surfactant, but since the cosmetic composition contains the cation-modified diutan gum, and thus has improved emulsion stability, the content of the surfactant may be less than usual. In a typical cosmetic composition, the content of the surfactant is 0.1 to 50% by mass relative to the total mass of the cosmetic composition, whereas in the cosmetic composition of the present embodiment, the content of the surfactant may be, for example, 0.1% by mass or less, or 0.01% by mass or less, and the cosmetic composition may not substantially contain the surfactant. In order to impart a function specific to the surfactant to the cosmetic composition, the content of the surfactant is preferably 10 to 40% by mass, and more preferably 10 to 20% by mass.

Examples of the surfactant include cationic surfactants, anionic surfactants, nonionic surfactants, and amphoteric surfactants. From the viewpoint that the surfactant exhibits compatibility with the cation-modified diutan gum, it is preferable that the surfactant contains any one of anionic surfactants, nonionic surfactants, and amphoteric surfactants. It is also more preferable that the surfactant contains a plurality of these. By combining the cation-modified diutan gum and the surfactant, the cosmetic composition has even better dispersion stability. In addition, the cosmetic composition has a function specific to the surfactant. For example, in the case of the cleansing cosmetic composition, the composition has a function of improving hair conditioning properties and improving foam quality.

Examples of the cationic surfactant include alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkylpyridinium salts, alkyldimethylbenzylammonium salts, benzethonium chloride, and benzalkonium chloride.

Examples of the anionic surfactants include alkyl (8-24 carbon atoms) sulfates, alkyl (8-24 carbon atoms) ether sulfates, alkyl (8-24 carbon atoms) benzenesulfonates, alkyl (8-24 carbon atoms) phosphates, polyoxyalkylene alkyl (8-24 carbon atoms) ether phosphates, alkyl (8-24 carbon atoms) sulfosuccinates, polyoxyalkylene alkyl (8-24 carbon atoms) ether sulfosuccinates, acylated (8-24 carbon atoms) alanine salts, and acylated phenylalanine salts. Examples of such acylated salts include acylated N-methyl-β-alanine salts (having 8 to 24 carbon atoms), acylated glutamate salts (having 8 to 24 carbon atoms), acylated isethionate salts (having 8 to 24 carbon atoms), acylated sarcosinate salts (having 8 to 24 carbon atoms), acylated taurine salts (having 8 to 24 carbon atoms), acylated methyl taurine salts (having 8 to 24 carbon atoms), α-sulfofatty acid ester salts, ether carboxylate salts, polyoxyalkylene fatty acid monoethanolamide sulfate salts, and long-chain (having 8 to 24 carbon atoms) carboxylate salts.

Examples of the nonionic surfactants include alkanolamides, glycerin fatty acid esters, polyoxyalkylene alkyl ethers, polyoxyalkylene glycol ethers, polyoxyalkylene sorbitan fatty acid esters, sorbitan fatty acid esters, polyoxyalkylene sorbitol fatty acid esters, sorbitol fatty acid esters, polyoxyalkylene glycerin fatty acid esters, polyoxyalkylene fatty acid esters, polyoxyalkylene alkylphenyl ethers, tetrapolyoxyalkylene ethylenediamine condensates, sucrose fatty acid esters, polyoxyalkylene fatty acid amides, polyoxyalkylene glycol fatty acid esters, polyoxyalkylene castor oil derivatives, polyoxyalkylene hydrogenated castor oil derivatives, alkyl polyglycosides, and polyglycerin fatty acid esters.

Examples of the amphoteric surfactants include alkyl (8-24 carbon atoms) amidopropyl betaine, alkyl (8-24 carbon atoms) carboxybetaine, alkyl (8-24 carbon atoms) sulfobetaine, alkyl (8-24 carbon atoms) hydroxysulfobetaine, alkyl (8-24 carbon atoms) amidopropyl hydroxysulfobetaine, alkyl (8-24 carbon atoms) hydroxyphosphobetaine, alkyl (8-24 carbon atoms) aminocarboxylate, alkyl (8-24 carbon atoms) amphoNa, alkyl (8-24 carbon atoms) amine oxide, and alkyl (8-24 carbon atoms) phosphate ester containing tertiary and quaternary nitrogen.

Furthermore, the cosmetic composition may contain other additives. Examples of the additives include polyhydric alcohols that function as moisturizing agents such as glycerin and 1,3-butylene glycol, thickeners such as xanthan gum, antioxidants such as tocopherol and BHT, UV absorbers such as benzophenone derivatives, para-aminobenzoic acid derivatives and methoxycinnamic acid derivatives, chelating agents such as edetate, amino acids such as arginine and glutamic acid, pH adjusters, bactericides, preservatives, vitamins, anti-inflammatory agents, colorants, fragrances, and foam enhancers.

（式中Ｒ^１及びＲ^２は炭素数１～３のアルキル基であり、Ｒ^３は炭素数１～２４のアルキル基であり、Ｒ^４及びＲ^５は炭素数１～３のアルキル基又は水素原子であり、Ｘ^－は１価の陰イオンを示す） As described above, the cation-modified diutan gum according to this embodiment has
A cation-modified diutan gum in which a part of the hydroxyl groups is substituted with a quaternary nitrogen-containing group represented by chemical formula (1),
The amount of cationic charge derived from the quaternary nitrogen-containing group is 0.3 to 0.8 meq/g.

(wherein ^R1 and ^R2 are alkyl groups having 1 to 3 carbon atoms, ^R3 is an alkyl group having 1 to 24 carbon atoms, ^R4 and ^R5 are alkyl groups having 1 to 3 carbon atoms or a hydrogen atom, and ^X- represents a monovalent anion.)

With this configuration, the cationic charge amount is 0.3 to 0.8 meq/g, thereby improving the dispersion stability of the liquid composition.

In addition, the cation-modified diutan gum according to this embodiment is preferably
^R4 and ^R5 are hydrogen atoms.

According to this configuration, since R ⁴ and R ⁵ are hydrogen atoms, the dispersion stability of the liquid composition can be further improved.

In addition, the cation-modified diutan gum according to this embodiment is preferably
^R3 is an alkyl group having 1 to 3 carbon atoms.

According to this configuration, since R ³ is an alkyl group having 1 to 3 carbon atoms, the dispersion stability of the liquid composition can be further improved.

In addition, the cation-modified diutan gum according to this embodiment is preferably
R ¹ , R ² and R ³ are methyl groups.

In this configuration, R ¹ , R ² and R ³ are methyl groups, so that the dispersion stability of the liquid composition can be further improved.

In addition, the dispersion stabilizer in this embodiment contains the above-mentioned cation-modified diutan gum.

According to this configuration, by including the above-mentioned cation-modified diutan gum, when it is included in a liquid composition or emulsion composition containing solid particles, it is possible to impart excellent dispersion stability to these compositions.

The cosmetic composition according to this embodiment also contains the above-mentioned cation-modified diutan gum.

With this configuration, the inclusion of the above-mentioned cation-modified diutan gum results in excellent dispersion stability.

In addition, the cosmetic composition according to this embodiment preferably contains a surfactant, and the surfactant contains either an anionic surfactant, an amphoteric surfactant, or a nonionic surfactant.

According to this configuration, the surfactant contains either an anionic surfactant, an amphoteric surfactant, or a nonionic surfactant, which results in excellent compatibility between the surfactant and the cation-modified diutan gum.

In addition, the cosmetic composition according to this embodiment is preferably a cosmetic composition for cleansing.

According to this configuration, since the cosmetic contains the cation-modified diutan gum, when used in a cosmetic for cleansing purposes, the cosmetic has excellent quality.

As described above, one embodiment has been shown as an example, but the cation-modified diutan gum of the present invention is not limited to the configuration of the above embodiment. Furthermore, the cation-modified diutan gum of the present invention is not limited by the above-mentioned action and effect. The cation-modified diutan gum of the present invention can be modified in various ways without departing from the gist of the present invention.

The present invention will be further explained below with reference to examples, but the present invention is not limited to these.

[Example 1]
1.55 g of sodium hydroxide was dissolved in 49.44 g of water, and 74.88 g of isopropanol was uniformly dissolved. Then, 30 g of diutan gum (KELCO-VIS DG, manufactured by CP Kelco U.S., Inc.) was added while being dispersed. 6.0 g of glycidyl trimethylammonium chloride (hereinafter sometimes referred to as GTA, SY-GTA80, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.) was added and reacted at 50 to 55°C for 4 hours. After the reaction was completed, the mixture was neutralized with 1.52 g of 50% by mass sulfuric acid. The reaction product was filtered, washed by dispersing in 131.52 g of 60% isopropanol, and then filtered. Next, the reaction product was washed by dispersing in 101.76 g of 75% isopropanol, and then filtered. Furthermore, the excess GTA was removed by washing by dispersing in 72 g of 90% methanol, and the target cation-modified diutan gum was obtained after drying. The cationic charge amount of the resulting cationically modified diutan gum was 0.443 meq/g. The results are shown in Table 1.

[Examples 2 to 3 and Comparative Examples 1 to 2]
Cation-modified diutan gums having different cationic charge amounts were produced in the same manner as in Example 1, except that the amount of GTA used for the cationic modification was set to the value shown in Table 1, and the cationic charge amounts were measured.

[Comparative Example 3]
The diutan gum used in Example 1 was used as Comparative Example 3, and its nitrogen content was measured.

As shown in Table 1, the nitrogen content and cationic charge of the cation-modified diutan gum increased as the amount of GTA increased. In other words, it was found that it is possible to adjust the cationic charge of the cation-modified diutan gum by changing the amount of GTA.

[FT-IR measurement of cation-modified diutan gum]
The IR spectra of Example 2 and Comparative Example 3 (unmodified diutan gum) were measured using a Fourier transform infrared spectrophotometer (FT/IR-4600, manufactured by JASCO Corporation, ATR method). The spectral data for comparing these are shown in FIG.

1, the cationically modified diutan gum of Example 2 exhibited a significant decrease in the peak intensity of the first peak P1 near 1730 cm ^- 1 compared to the unmodified diutan gum of Comparative Example 3. Similarly, the peak intensities of the peaks near 1250 cm ^-1 and 1400 cm ^-1 were also decreased. In contrast, no significant change was observed in the peak intensity of the second peak P2 near 1600 cm ^-1 .

In addition, the ratio of the peak intensity of the first peak P1 to the peak intensity of the second peak P2 in the IR spectrum was calculated.
The peak intensity ratio was measured by comparing the distance from a straight line passing through the high wavenumber end of the first peak (near 1770 cm ^-1 ) and the low wavenumber end of the second peak (near 1500 cm ^-1 ) in the IR spectrum to the peak top of each peak, which was set as a baseline.
The peak intensity ratio in Example 2 was 0.20, whereas the peak intensity ratio in Comparative Example 3 was 0.73.

[Evaluation A: Evaluation of Dispersion Stability of Solid Particles]
Aqueous solutions with a polysaccharide concentration of 0.25% by mass were prepared using the cation-modified diutan gums of Examples 1 to 3 and Comparative Examples 1 and 2, and the diutan gum and cation-modified xanthan gum (Labor Gum CX, manufactured by DSP Gokyo Food & Chemical Co., Ltd.) of Comparative Example 3, and the dispersion stability was evaluated by dispersing a scrubbing agent as solid particles in the aqueous solutions. The viscosity of the 0.25% by mass aqueous solutions was measured under the following measurement conditions.
Specifically, 99.65 g of deionized water was placed in a 200 mL glass beaker, and 0.25 g of each polysaccharide and 0.10 g of methylparaben were added while stirring with a general-purpose stirrer (BL1200, manufactured by Shinto Scientific Co., Ltd.). The mixture was stirred at room temperature for 1 hour to obtain a 0.25% by weight aqueous solution. 80 g of each 0.25% by weight aqueous solution and 4 g of a scrubbing agent (synthetic wax (organic solid particles), specific gravity 0.95, Synscrub164GRS, manufactured by Micro Powders, Inc.) were placed in a 100 mL vial, and the mixture was shaken up and down to uniformly disperse the scrubbing agent. The obtained dispersion was placed in a 50 ° C. incubator (MIR-153, manufactured by Sanyo Electric Co., Ltd. (now Panasonic Corporation)), and the state after standing for 24 hours was observed and evaluated according to the following evaluation criteria. The results are shown in Table 2.

(Evaluation Criteria for Dispersion Stability)
Stable: The scrubbing agent does not float near the liquid surface, and no layer of scrubbing agent is visible on the liquid surface.
Unstable: The scrubbing agent is floating near the liquid surface, and a layer of scrubbing agent is visible on the liquid surface.

(Viscosity measurement conditions)
The 0.25% by mass aqueous solution before the addition of the scrubbing agent was subjected to a rheometer (DHR-2, manufactured by TA Instruments Japan, Inc.) and the viscosity at a shear rate of 0.01 s ^-1 was measured by flow curve measurement (temperature: 25°C).

As shown in Table 2, in the aqueous solutions (A-1 to A-3) containing Examples 1 to 3, the low specific gravity solid particle scrubbing agent did not float at all, and the dispersion state of the scrubbing agent was maintained uniformly. In contrast, in the aqueous solutions (A-4 to A-6) containing Comparative Examples 1 to 3 or the aqueous solution (A-7) containing cation-modified xanthan gum, the scrubbing agent floated, and a layer of the scrubbing agent was observed on the liquid surface.
In general, it is believed that the higher the viscosity in the low shear region (0.01 s ^-1 ) close to the stationary state, the higher the dispersion stability of solid particles such as scrubbing agents. For this reason, it was speculated that the aqueous solutions containing Examples 1 to 3 had high viscosities. However, unexpectedly, the viscosities of the aqueous solutions containing Examples 1 to 3 were lower than that of the aqueous solution containing Comparative Example 3 (unmodified diutan gum), which had insufficient dispersion stability. In particular, the aqueous solution containing Example 3 had good dispersion stability, despite having a lower viscosity than any of the aqueous solutions containing Comparative Examples 1 to 3. From this, it was found that the cation-modified diutan gums of Examples 1 to 3 exhibited very excellent dispersion stability regardless of viscosity.
Therefore, it was found that the cationically modified diutan gums of Examples 1 to 3 had better dispersion stability than the cationically modified xanthan gum.

[Evaluation B: Evaluation of Dispersion Stability of Emulsion Particles]
Using the cation-modified diutan gums of Examples 1 to 3 and Comparative Examples 1 and 2, and the diutan gum of Comparative Example 3, emulsions with a polysaccharide concentration of 0.25% by mass and an oil component concentration of 40% by mass were prepared, and the dispersion stability of the emulsion particles was evaluated.
Specifically, 100 g of deionized water was placed in a 300 mL tall glass beaker, and 0.5 g of each polysaccharide was added while stirring with a general-purpose stirrer (BL1200, manufactured by Shinto Scientific Co., Ltd.). After stirring at room temperature for 1 hour, 80 g of liquid paraffin and 0.2 g of methylparaben were added, and deionized water was further added to make a total of 200 g. After stirring at about 1000 rpm (pre-emulsification) with the general-purpose stirrer for 5 minutes, stirring (emulsification) was performed at 8000 rpm with a homogenizer (TK Robomix, stirring part: T.K. Homomixer MARK II 2.5 type, manufactured by Primix Corporation) for 5 minutes.
The emulsion particle size (median size) of the obtained emulsion was measured using a laser diffraction/scattering type particle size distribution measuring device (Partica mini LA-350, manufactured by Horiba, Ltd.) (dispersion medium: water). The results are shown in Table 3.

As shown in Table 3, in the emulsions containing Examples 1 to 3 (B-1 to B-3), the emulsion particles were less than 50 μm, which was smaller than the emulsions containing Comparative Examples 1 to 3 (B-4 to B-6). This shows that the cation-modified diutan gums of Examples 1 to 3 are also superior in terms of dispersion stability of the emulsion particles to the cation-modified diutan gums of Comparative Examples 1 to 3. In addition, because the emulsion particles can be made smaller, it is expected that the amount of surfactant can be reduced when preparing an emulsion composition. Furthermore, because the dispersion stability is excellent, it is expected that the stability (emulsion stability) of the emulsion composition will also be very high.

[Evaluation C: Evaluation of spinnability]
The cation-modified diutan gums of Examples 1 to 3 and Comparative Examples 1 and 2, and the diutan gum of Comparative Example 3 were used to evaluate the spinnability of an aqueous solution having a polysaccharide concentration of 0.5% by mass.
Specifically, 98.0 g of deionized water was placed in a 200 mL glass beaker, and 2.0 g of each polysaccharide was added while stirring with a general-purpose stirrer (BL1200, manufactured by Shinto Scientific Co., Ltd.). Stirring was performed for 1 hour at room temperature to obtain a 2.0% by mass aqueous solution. 12.5 g of a 2.0% by mass aqueous solution and 37.5 g of deionized water were placed in a 100 mL glass beaker, and the solution was uniformly mixed by stirring with a general-purpose stirrer at room temperature for 10 minutes to obtain a 0.5% by mass aqueous solution. 25 g of each 0.5% by mass aqueous solution was placed in a plastic dish with a diameter of 60 mm, and the plunger (diameter 8 mm) of a creep meter (RE2-33005S, manufactured by Yamaden Co., Ltd.) was brought into contact with the surface of the aqueous solution, and the plunger and the aqueous solution were separated at a speed of 5 mm/sec. The time until the solution ran out was measured. The time was calculated using the following formula, and the average value of five times was taken as the spinnability. The results are shown in Table 4.

Spinnability (mm) = Time until the solution runs out (sec) x Speed (5 mm/sec)

As shown in Table 4, the aqueous solutions containing Examples 1 to 3 (C-1 to C-3) and the aqueous solutions containing Comparative Examples 1 and 2 (C-4 to C-5) had lower spinnability than the aqueous solution containing Comparative Example 3 (C-6). Furthermore, the aqueous solutions containing Examples 1 to 3 had lower spinnability than the aqueous solutions containing Comparative Examples 1 and 2.
If the composition has strong stringiness, it may adhere to the sealed portion during the process of filling a container such as a tube, which may result in poor sealing or leakage. Therefore, the composition is required to break quickly without stringing during filling.
In this regard, it was found that the cation-modified diutan gums of Examples 1 to 3 have low spinnability and therefore can improve the manufacturability of the products.

[Evaluation D: Evaluation of transparency]
In addition, a 0.5% by mass aqueous solution of cation-modified diutan gum prepared in the same manner as above, and a 0.5% by mass aqueous solution of unmodified diutan gum prepared in the same manner were placed in a 1 cm long disposable cell, and the transmittance at 600 nm was measured using a spectrophotometer (U-2910, manufactured by Hitachi High-Technologies Corporation).
As a result, the aqueous solutions containing the cationically modified diutan gum of Examples 1 to 3 had improved transmittance and a good appearance with less turbidity compared to the aqueous solution containing unmodified diutan gum of Comparative Example 3.
Therefore, it was found that the cation-modified diutan gums of Examples 1 to 3 can suppress coloration of products and can be particularly suitably used in cosmetic compositions.

To summarize the above evaluation results, it was found that the cation-modified diutan gums in Examples 1 to 3 with cationic charge amounts of 0.3 to 0.8 meq/g are polysaccharides with extremely excellent dispersion stability. Therefore, in the field of cosmetics, for example, the cation-modified diutan gums in Examples 1 to 3 contribute to the dispersion stability of scrubs, pigments, emulsified particles, etc., and are useful in applications such as lotions, milky lotions, serums, gels, creams, facial cleansers, sunscreens, shampoos, treatments, and body soaps.

Next, we decided to confirm the dispersion stability exhibited by cation-modified diutan gum with a cationic charge of 0.3 to 0.8 meq/g in several cosmetic compositions.

[Evaluation E: Evaluation of Dispersion Stability of Solid Particles in a Facial Scrub Cleanser]
Using the cation-modified diutan gums of Examples 1 and 3 and the cation-modified xanthan gum (Labor Gum CX, manufactured by DSP Gokyo Food & Chemical Co., Ltd.), a facial scrub cleanser was prepared with the composition shown in Table 5. The specific gravity of the polylactic acid (organic solid particles) used as the scrubbing agent was 1.25.
Specifically, the component (1) shown in Table 5 was placed in a 30 mL glass beaker, and the component (2) was added and mixed uniformly to obtain a dispersion. The component (3) was placed in a 100 mL tall glass beaker, and the dispersion was added while stirring with a general-purpose stirrer (BL1200, manufactured by Shinto Scientific Co., Ltd.), and the beaker was then immersed in a water bath at 85 ° C. After the liquid temperature reached 80 ° C, the mixture was stirred for 15 minutes, and a mixture of components (4) to (6) was added. Next, components (7) and (8) were added, and the mixture was cooled with water while stirring until it reached near room temperature, and component (3) was added to a total of 50 g to prepare a scrub face wash. 10 g of the obtained scrub face wash was placed in a 10 mL screw-top test tube and left to stand in a 50 ° C incubator (MIR-153, manufactured by Sanyo Electric Co., Ltd. (now Panasonic Corporation)), and the state was observed after 3 days. The results of evaluation based on the following evaluation criteria are shown in Table 8.

(Evaluation Criteria for Dispersion Stability of Scrub Facial Wash)
Stable: The scrubbing agent does not settle and no sedimentary layer of the scrubbing agent is observed.
Unstable: The scrubbing agent settles and a sediment layer of the scrubbing agent is observed.

As shown in Table 5, in scrub cleansers containing high specific gravity solid particles, the scrub cleansers containing Example 1 or Example 3 (E-1 or E-2) showed better dispersion stability than the scrub cleansers containing cation-modified xanthan gum (E-3), which is considered to have high dispersion stability.

[Evaluation F: Evaluation of dispersion stability of emulsion particles in oil-in-lotion]
Oil-in lotions having the formulations shown in Table 6 were prepared using Examples 1 to 3 and Comparative Example 3, as well as cation-modified xanthan gum (Labor Gum CX, manufactured by DSP Gokyo Food & Chemical Co., Ltd.) and cation-modified guar gum (Labor Gum CG-M, manufactured by DSP Gokyo Food & Chemical Co., Ltd.).
Specifically, component (1) shown in Table 6 was placed in a 30 mL glass beaker, and component (2) was added and mixed uniformly to obtain a dispersion. Component (3) was placed in a 200 mL tall glass beaker, and the dispersion was added while stirring with a general-purpose stirrer (BL1200, manufactured by Shinto Scientific Co., Ltd.), and then stirred at room temperature for 30 minutes. Next, components (4) to (6) were added in order and stirred for 5 minutes. Component (7) was added to the obtained lotion and stirred at 300 rpm for 5 minutes to prepare a total of 105 g of oil-in lotion. 80 g of the obtained oil-in lotion was transferred to a 100 mL vial and left to stand in a thermostat (MIR-153, manufactured by Sanyo Electric Co., Ltd. (now Panasonic Corporation)) at 50° C., and the state was observed after 6 days. The results of evaluation based on the following evaluation criteria are shown in Table 6.

(Evaluation Criteria for Dispersion Stability of Oil-in-Lotion)
Stable: Olive oil particles do not float or separate from the aqueous solution.
Unstable: Olive oil particles rise to the surface and form a separate layer from the aqueous solution.

As shown in Table 6, the oil-in lotions containing Examples 1 to 3 (F-1 to F-3) showed superior dispersion stability to unmodified diutan gum (F-4), cationically modified guar gum (F-6), and oil-in lotion containing cationically modified xanthan gum (F-5), which is considered to have high dispersion stability.

[Evaluation G: Evaluation of long-term dispersion stability of solid particles and oil droplets (emulsion particles)]
Aqueous solutions with a polysaccharide concentration of 0.25% by mass were prepared using the cation-modified diutan gums of Examples 1 to 3 and Comparative Examples 1 and 2, and the diutan gum of Comparative Example 3, and the dispersion stability was evaluated by dispersing a scrubbing agent (the synthetic wax (organic solid particles) used in Evaluation A) and calcium carbonate (inorganic solid particles) as solid particles, and liquid paraffin (hydrocarbon oil) as oil droplets in these solutions.
Specifically, 99.65 g of deionized water was placed in a 200 mL glass beaker, and 0.25 g of each polysaccharide and 0.10 g of methylparaben were added while stirring with a general-purpose stirrer (BL1200, manufactured by Shinto Scientific Co., Ltd.). The mixture was stirred at room temperature for 1 hour to obtain a 0.25% by mass aqueous solution of each polysaccharide. 8 g of each 0.25% by mass aqueous solution and 0.4 g of a scrubbing agent (synthetic wax (organic solid particles), specific gravity 0.95, Synscrub164GRS, manufactured by Micro Powders, Inc.), calcium carbonate (specific gravity 2.71, manufactured by Nacalai Tesque Co., Ltd.), and liquid paraffin (specific gravity 0.86 to 0.89, manufactured by Nacalai Tesque Co., Ltd.) were added to a 10 mL vial, and the mixture was shaken up and down to uniformly disperse the solid particles or oil droplets. The obtained dispersion was placed in a thermostatic chamber (MIR-153, manufactured by Sanyo Electric Co., Ltd. (currently Panasonic Corporation)) at 50° C. and allowed to stand for 90 days, after which the state was observed and evaluated according to the following evaluation criteria. The results are shown in Table 7.

(Evaluation Criteria for Dispersion Stability of Scrub Agent)
Stable: The scrubbing agent does not float near the liquid surface, and no layer of scrubbing agent is visible on the liquid surface.
Unstable: The scrubbing agent is floating near the liquid surface, and a layer of scrubbing agent is visible on the liquid surface.
(Evaluation Criteria for Dispersion Stability of Calcium Carbonate)
Stable: No calcium carbonate settles near the bottom and no layer of calcium carbonate is visible at the bottom.
Unstable: Calcium carbonate has settled near the bottom and a layer of calcium carbonate is visible at the bottom.
(Evaluation Criteria for Dispersion Stability of Liquid Paraffin)
Stable: Liquid paraffin does not float near the liquid surface, and no layer of liquid paraffin is visible on the liquid surface.
Unstable: Liquid paraffin is floating near the liquid surface, and a layer of liquid paraffin is visible on the liquid surface.

As shown in Table 7, in the aqueous solutions (G-1 to G-3) containing Examples 1 to 3, even after a long storage period (90 days), no floating of the low specific gravity solid particle scrubbing agent and low specific gravity oil agent was observed. In addition, no settling of the high specific gravity particle calcium carbonate was observed. In other words, the aqueous solutions (G-1 to G-3) containing Examples 1 to 3 maintained a uniform dispersion state of the solid particles and emulsified particles for a long period of time.
In contrast, in the aqueous solutions containing Comparative Examples 1 to 3 (G-4 to G-6), the floating of the scrubbing agent and liquid paraffin was observed, a layer of the scrubbing agent and liquid paraffin was observed on the liquid surface, or a layer of calcium carbonate formed by precipitation of calcium carbonate was observed.

[Evaluation H: Evaluation of compatibility with anionic surfactants]
Compositions containing anionic surfactants were prepared using the cationically modified diutan gums of Examples 1 to 3 and Comparative Examples 1 and 2, and the diutan gum of Comparative Example 3, and the compatibility of each polysaccharide with the anionic surfactant was evaluated. The viscosity of these compositions was also evaluated by the following measurement.
Specifically, 29.4 g of deionized water was placed in a 100 mL glass beaker, and 0.6 g of each polysaccharide was added while stirring with a general-purpose stirrer (BL1200, manufactured by Shinto Scientific Co., Ltd.). Stirring was performed at room temperature for 1 hour to obtain an aqueous solution with a polysaccharide concentration of 2.0% by mass. 5 g of the aqueous solution was dispensed into four 15 mL conical tubes, and each conical tube was charged with sodium lauryl sulfate (alkyl sulfate having 12 carbon atoms, EMALE 0 manufactured by Kao Corporation, 10% by mass relative to the total mass of the composition), a 30% aqueous solution of sodium lauroyl sarcosine (acylated sarcosine salt having 12 carbon atoms, Sarcosinate LN-30 manufactured by Nikko Chemicals Co., Ltd., 33.4% by mass relative to the total mass of the composition), a 30% aqueous solution of sodium lauroyl methylalanine (acylated N-methyl-β-alanine salt having 12 carbon atoms), and a 20% aqueous solution of sodium lauroyl methylalanine (acylated N-methyl-β-alanine salt having 12 carbon atoms). , Alaninate LN-30 manufactured by Nikko Chemicals Co., Ltd., 33.4% by mass relative to the total mass of the composition, or a 35% aqueous solution of potassium hydroxide containing lauric acid, myristic acid, palmitic acid, and glycerin (i.e., an aqueous solution containing a long-chain carboxylate having 12 carbon atoms, a long-chain carboxylate having 14 carbon atoms, and a long-chain carboxylate having 16 carbon atoms as an anionic surfactant, Prior B-100 manufactured by Kao Corporation, 28.6% by mass relative to the total mass of the composition), and further deionized water was added to obtain a composition of 10 g. After mixing with a spatula, the mixture was homogenized at 10,000 rpm for 1 to 2 minutes using a homogenizer (HG-200, manufactured by Hsiangtai). The appearance of the obtained aqueous solution was observed and evaluated according to the following evaluation criteria. The results are shown in Table 8.

（粘度測定条件）
界面活性剤を添加した場合と添加しなかった場合の水溶液をレオメータ（ＤＨＲ－２、ティー・エイ・インスツルメント・ジャパン株式会社製）に供し、フローカーブ測定（温度：２５℃）にて１０ｓ^－１のせん断速度における粘度を測定した。 (Evaluation Criteria for Compatibility with Anionic Surfactants)
Good compatibility: No aggregation is observed, and the residual viscosity is 70% or more.
Compatible: No aggregation is observed, but the residual viscosity is less than 70%.
No compatibility: Aggregation is observed.
(Residual Viscosity Rate)
The viscosity residual rate was calculated by the following formula.

(Viscosity measurement conditions)
The aqueous solutions with and without the addition of a surfactant were subjected to a rheometer (DHR-2, manufactured by TA Instruments Japan, Inc.) to measure the viscosity at a shear rate of 10 s ⁻¹ by flow curve measurement (temperature: 25° C.).

As shown in Table 8, when the aqueous solutions (H-1 to H-3) containing Examples 1 to 3 were mixed with the four anionic surfactants, no aggregation was observed and the viscosity was maintained.
In contrast, the aqueous solution (H-4) containing Comparative Example 1 showed a large decrease in viscosity when mixed with sodium lauroylmethylalanine. The aqueous solution (H-5) containing Comparative Example 2 showed aggregation when mixed with sodium lauryl sulfate. The aqueous solution (H-6) containing Comparative Example 3 showed a decrease in viscosity when mixed with sodium lauryl sulfate, sodium lauroyl sarcosine, or sodium lauroylmethylalanine, and showed aggregation when mixed with sodium lauroyl sarcosine or sodium lauroylmethylalanine.
These results demonstrate that the cationically modified diutan gums of Examples 1 to 3 have excellent compatibility with anionic surfactants.

Next, several cosmetic compositions in various formulations were prepared using the cation-modified diutan gum of the present invention having a cationic charge of 0.3 to 0.8 meq/g, and the compatibility of the cation-modified diutan gum with surfactants and the dispersion stability of the cosmetic compositions were evaluated.

[Evaluation I: Evaluation of compatibility with surfactants and dispersion stability of solid particles in gel shampoo]
A gel shampoo having the composition shown in Table 9 was prepared using the cation-modified diutan gum of Example 1 and the diutan gum of Comparative Example 3. The specific gravity of the carnauba wax (organic solid particles) used as the scrubbing agent was 0.99.
Specifically, component (1) shown in Table 9 was placed in a 100 mL glass beaker, and component (2) was added while stirring with a general-purpose stirrer (BL1200, manufactured by Shinto Scientific Co., Ltd.), followed by stirring at room temperature for 10 minutes, and then component (3) was added and stirred at room temperature for 20 minutes. Next, components (4) and (5) were added and stirred for 5 minutes. Furthermore, components (6) to (8) were added and stirred for 10 minutes to prepare a gel shampoo. The appearance of the obtained gel shampoo was observed to confirm the presence or absence of aggregation. In addition, the mixture was subjected to a rheometer (DHR-2, manufactured by TA Instruments Japan Co., Ltd.) and the viscosity at a shear rate of 10 s ^-1 was measured by flow curve measurement (temperature: 25°C). Further, 8 g of the obtained gel shampoo and 0.5 g of a scrubbing agent (carnauba wax, specific gravity 0.99, NATURESCRUB C20, manufactured by Micro Powders, Inc.) were added to a 10 mL vial, and the vial was shaken up and down to uniformly disperse the scrubbing agent in the scrub gel shampoo. The obtained scrub gel shampoo was left to stand in a thermostat (MIR-153, manufactured by Sanyo Electric Co., Ltd. (now Panasonic Corporation)) at 40°C, and the state was observed after one day. The results of evaluation based on the following evaluation criteria are shown in Table 9.

(Evaluation criteria for compatibility with surfactants in gel shampoos)
Good compatibility: no aggregation observed.
No compatibility: Aggregation is observed.
(Evaluation criteria for dispersion stability of scrub gel shampoo)
Stable: No settling or floating of the scrubbing agent is observed, and no layer of scrubbing agent is observed on the liquid surface or near the bottom.
Unstable: Settling or floating of the scrubbing agent is observed, and a layer of scrubbing agent is observed near the liquid surface or bottom.

As shown in Table 9, the gel shampoo (I-1) containing Example 1 showed no aggregation and a high viscosity value.
In contrast, the gel shampoo (I-2) containing Comparative Example 3 caused aggregation when mixed with components (6) to (8), and also showed a lower viscosity value than that of Example 1.
These results show that the gel shampoo containing Example 1 has better compatibility with anionic surfactants and amphoteric surfactants than the gel shampoo containing Comparative Example 3.
Furthermore, in the scrub gel shampoos containing low specific gravity solid particles close to that of water, it was found that the scrub gel shampoo (I-1) containing Example 1 had better dispersion stability than the scrub gel shampoo (I-2) containing Comparative Example 3.

[Evaluation J: Evaluation of compatibility with surfactants in body soap and dispersion stability of solid particles]
Using the cation-modified diutan gum of Example 3 and the diutan gum of Comparative Example 3, a body soap having the composition shown in Table 10 was prepared. The specific gravity of the polyhydroxybutyric acid (organic solid particles) used as the scrubbing agent was 1.25.
Specifically, the component (1) shown in Table 10 was placed in a 100 mL glass beaker, and the component (2) and the component (3) were added while stirring with a general-purpose stirrer (BL1200, manufactured by Shinto Scientific Co., Ltd.), and the beaker was then immersed in a water bath at 83 ° C. After the liquid temperature reached 80 ° C., the mixture was stirred for 15 minutes, and the components (4) to (7) were added and stirred for 5 minutes. The mixture was then cooled with water until it reached near room temperature, and the component (8) was added, followed by adding the component (1) so that the total amount became 50 g, to prepare a body soap. The appearance of the obtained body soap was observed to confirm the presence or absence of aggregation. The mixture was also subjected to a rheometer (DHR-2, manufactured by TA Instruments Japan Co., Ltd.) to measure the viscosity at a shear rate of 10 s ^-1 by flow curve measurement (temperature: 25 ° C.). Further, 8 g of the obtained body soap and 0.5 g of a scrub agent (polyhydroxybutyric acid, specific gravity 1.25, BIOSCRUB 50PC, manufactured by Micro Powders, Inc.) were added to a 10 mL vial, and the scrub agent in the scrub body soap was uniformly dispersed by shaking up and down. The obtained scrub body soap was left to stand in a thermostat (MIR-153, manufactured by SANYO Electric Co., Ltd. (now Panasonic Corporation)) at 40°C, and the state was observed after 1 day. The results of evaluation based on the following evaluation criteria are shown in Table 10.

(Evaluation criteria for compatibility with surfactants in body soap)
Good compatibility: no aggregation observed.
No compatibility: Aggregation is observed.
(Evaluation Criteria for Dispersion Stability of Scrub Body Soap)
Stable: No settling of the scrubbing agent is observed and no sediment layer of the scrubbing agent is observed.
Unstable: Settling of the scrubbing agent is observed, and a sediment layer of the scrubbing agent is observed.

As shown in Table 10, the body soap (J-1) containing Example 3 showed no aggregation and a high viscosity value.
In contrast, the body soap (J-2) containing Comparative Example 3 caused aggregation when mixed with components (4) to (7), and also showed a lower viscosity value than that of Example 3.
From these results, it was found that the body soap containing Example 3 has better compatibility with anionic surfactants and nonionic surfactants than the body soap containing Comparative Example 3.
In addition, it was found that, in the scrub body soaps containing high specific gravity solid particles, the scrub body soap containing Example 3 (J-1) had better dispersion stability than the scrub body soap containing Comparative Example 3 (J-2).

P1: first peak, P2: second peak

Claims (6)

A cation-modified diutan gum in which a part of the hydroxyl groups is substituted with a quaternary nitrogen-containing group represented by chemical formula (1),
A cationically modified diutan gum, wherein the amount of cationic charge derived from the quaternary nitrogen-containing group is 0.44 to 0.7 meq/g.
(wherein ^R1 and ^R2 are alkyl groups having 1 to 3 carbon atoms, ^R3 is an alkyl group having 1 to 24 carbon atoms, ^R4 and ^R5 are alkyl groups having 1 to 3 carbon atoms or a hydrogen atom, and ^X- represents a monovalent anion.) 2. The cationically modified diutan gum according to claim 1, wherein ^R4 and ^R5 are hydrogen atoms. The cation modified diutan gum according to claim 1 or 2, wherein R ³ is an alkyl group having 1 to 3 carbon atoms. 4. A cationically modified diutan gum according to any one of claims 1 to 3, wherein R ¹ , R ² and R ³ are methyl groups. A dispersion stabilizer containing the cation-modified diutan gum according to any one of claims 1 to 4. A cosmetic composition containing the cation-modified diutan gum according to any one of claims 1 to 4.

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