JP2021172727A - Chitosan derivative and method for producing the same, o/w type emulsion composition, and cosmetic - Google Patents

Abstract

To provide a chitosan derivative excellent in emulsification performance in the range from neutral to alkaline region that can finely disperse various oils in water and prepare an emulsion composition.SOLUTION: Provided is a chitosan derivative in which a first substituent group derived from an acid modification agent and a second substituent group derived from a siloxane compound represented by the general formula (1) are introduced into chitosan, and the value of the ratio (A/S) of the introduction rate (A) of the first substituent group to the introduction rate (S) of the second substituent group is 2.0 to 25.0. Z-Y-Si(R1)a{[-O-Si(R2)(R3)]b-R4}3-a -- (1). (Z: functional group that can react with the reactive functional groups of chitosan, Y: alkylene group having 2 to 8 carbon atoms, which may have an oxygen atom or the like, R1, R2, R3, and R4: monovalent organic group having 1 to 8 carbon atoms, or group represented by the general formula (2) (-O-Si(R5)(R6)(R7))).SELECTED DRAWING: None

Description

The present invention relates to chitosan derivatives and methods for producing them, O / W type emulsified compositions, and cosmetics.

Low-molecular-weight surfactants, which are widely used in the fields of cosmetics, foods, detergents, etc., have high surface-active ability, but have a structure similar to that of lipid molecules, so that they are irritating due to penetration into the skin. There is concern. On the other hand, petroleum-derived polymer surfactants are difficult to be taken into the human body and can be said to be relatively excellent in safety, but because of their poor biocompatibility, they can be used in fields such as emulsifiers for foods. It tends to be restricted. Therefore, surfactants made from natural product-derived polysaccharides have been actively developed.

For example, siloxane-modified polysaccharides obtained by grafting organopolysiloxane to polysaccharides can be used in film-forming cosmetics used for hair and skin, as well as in gas separation films, backcoat agents for heat-sensitive transfer, and paints. It is useful as an ingredient to be blended.

The emulsifier used as a raw material for cosmetics is required to have a high molecular weight having low permeability to the skin. For example, a chitosan derivative in which a long-chain fatty acid is grafted on chitosan and is blended in cosmetics and the like has been proposed (Patent Document 1). In addition, siloxane-modified chitosan used as an emulsifier for preparing emulsions such as cosmetics has been proposed (Patent Document 2). Further, a chitosan derivative used as a polymer surfactant in which a long-chain fatty acid grafted product of chitosan is acylated with a polyvalent fatty acid has been proposed (Patent Document 3).

Japanese Unexamined Patent Publication No. 2000-212203 JP-A-2018-35306 Japanese Unexamined Patent Publication No. 2005-213494

When the chitosan derivatives and the like proposed in Patent Documents 1 and 2 are used as emulsifiers for cosmetics, it is considered that a weakly basic amino group functions as a dissociating group of chitosan. Therefore, in the neutral to alkaline pH range, the chitosan derivative and the like are precipitated, and the function as an emulsifier is likely to be lost. Further, in the chitosan derivative proposed in Patent Document 3, the amino group of chitosan is acylated with a polyunsaturated fatty acid to weaken the chitosan's cationic properties. However, it cannot be said that the function as an emulsifier and the stability of the prepared emulsified composition are sufficient.

The present invention has been made in view of the problems of the prior art, and the subject thereof is that it is possible to prepare an emulsified composition by finely dispersing various oils in water. An object of the present invention is to provide a chitosan derivative having excellent emulsifying performance in the neutral to alkaline range. Another object of the present invention is to provide a method for producing this chitosan derivative, an O / W type emulsified composition using this chitosan derivative, and a cosmetic.

That is, according to the present invention, the chitosan derivatives shown below are provided.
[1] A first substituent derived from an acid modifier and a second substituent derived from a siloxane compound represented by the following general formula (1) are introduced into chitosan, and the second substituent is used. A chitosan derivative in which the value of the ratio (A / S) of the introduction rate (A) of the first substituent to the introduction rate (S) is 2.0 to 25.0.
ZZ-Y-Si (R ₁ ) _a {[-O-Si (R ₂ ) (R ₃ )] _b- R ₄ } _3-a ... (1)
(In the general formula (1), Z represents a functional group capable of reacting with the reactive functional group of the chitosan, and Y may have an oxygen atom, a nitrogen atom, or a sulfur atom, and has 2 carbon atoms. Representing an alkylene group of ~ 8, R ₁ , R ₂ , R ₃ and R ₄ are independently monovalent organic groups having 1 to 8 carbon atoms or groups represented by the following general formula (2). , A indicates an integer of 0 to 3, and b indicates an integer of 1 to 10).
-O-Si (R ₅ ) (R ₆ ) (R ₇ ) ... (2)
(In the general formula (2), R ₅ , R ₆ and R ₇ each independently represent a monovalent organic group having 1 to 8 carbon atoms).
[2] The chitosan derivative according to the above [1], wherein the acid denaturing agent is a halogenated fatty acid.
[3] The chitosan derivative according to the above [2], wherein the halogenated fatty acid is at least one selected from the group consisting of chloroacetic acid, 3-chloropropionic acid, and 4-chlorobutanoic acid.
[4] The chitosan derivative according to any one of the above [1] to [3], which is used as a polymer surfactant.

Further, according to the present invention, the following method for producing a chitosan derivative is provided.
[5] The method for producing a chitosan derivative according to any one of the above [1] to [4], wherein the acid modifier and the siloxane compound are reacted with the chitosan to obtain the first substituent and the above. A method for producing a chitosan derivative, which comprises introducing a second substituent into the chitosan.
[6] The method for producing a chitosan derivative according to the above [5], wherein the chitosan is reacted with the acid denaturing agent and then the siloxane compound is reacted.

Further, according to the present invention, the following O / W type emulsified compositions and cosmetics are provided.
[7] O which contains water, oil, and an emulsifier that disperses the oil in the form of emulsified droplets in the water, and the emulsifier is the chitosan derivative according to any one of the above [1] to [4]. / W type emulsifying composition.
[8] The O / W type emulsified composition according to the above [7], wherein the median diameter (d _{50) of the emulsified droplet is 12.0 μm or less.}
[9] A cosmetic containing the chitosan derivative according to any one of the above [1] to [4].

According to the present invention, it is possible to provide a chitosan derivative having excellent emulsification performance in the neutral to alkaline range, which can prepare an emulsifying composition by finely dispersing various oils in water. Further, according to the present invention, it is possible to provide a method for producing this chitosan derivative, an O / W type emulsified composition using this chitosan derivative, and a cosmetic.

<Chitosan derivative>
Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments. In the chitosan derivative of the present invention, a first substituent derived from an acid denaturing agent and a second substituent derived from a siloxane compound represented by the following general formula (1) are introduced into chitosan. The value of the ratio (A / S) of the introduction rate (A) of the first substituent to the introduction rate (S) of the second substituent is 2.0 to 25.0. Hereinafter, the details of the chitosan derivative of the present invention will be described.

ZZ-Y-Si (R ₁ ) _a {[-O-Si (R ₂ ) (R ₃ )] _b- R ₄ } _3-a ... (1)
(In the general formula (1), Z represents a functional group capable of reacting with the reactive functional group of the chitosan, and Y may have an oxygen atom, a nitrogen atom, or a sulfur atom, and has 2 carbon atoms. Representing an alkylene group of ~ 8, R ₁ , R ₂ , R ₃ and R ₄ are independently monovalent organic groups having 1 to 8 carbon atoms or groups represented by the following general formula (2). , A indicates an integer of 0 to 3, and b indicates an integer of 1 to 10).

-O-Si (R ₅ ) (R ₆ ) (R ₇ ) ... (2)
(In the general formula (2), R ₅ , R ₆ and R ₇ each independently represent a monovalent organic group having 1 to 8 carbon atoms).

Chitosan is a compound that essentially has a cationic property because it has an amino group, which is a reactive group. In the chitosan derivative of the present invention, an acid modifier and a specific siloxane compound having a reactive functional group (hereinafter, also referred to as “modifier”) are reacted with chitosan, and the first derived from each of these modifiers. It was formed by introducing the substituent of No. 1 and the second substituent into chitosan. Furthermore, by controlling the value of the ratio (A / S) of the introduction rate (A) of the first substituent to the introduction rate (S) of the second substituent within a specific range, chitosan's original cationic Appropriately changing properties to nonionic or anionic properties. Therefore, the chitosan derivative of the present invention has excellent emulsifying performance even in the neutral to alkaline range, and is used when blended in a composition such as cosmetics prescribed in the neutral to alkaline range. However, excellent emulsification performance is exhibited. Further, by controlling the value of the ratio (A / S) of the introduction rate (A) of the first substituent to the introduction rate (S) of the second substituent within a predetermined range, the neutral to alkaline range Even oils (for example, silicone oil) that were relatively difficult to finely disperse in water were easily finely dispersed to prepare a stable emulsion. be able to.

(Chitosan)
Chitosan is a deacetylase of chitin obtained from crustaceans and filamentous fungi, has moisturizing and anticholesterol effects, is excellent in safety, and has been put into practical use as a raw material for cosmetics and functional foods. Chitosan is industrially produced and various grades are available.

The weight average molecular weight of chitosan is preferably 2,000 to 1,000,000, more preferably 5,000 to 800,000, and particularly preferably 10,000 to 600,000. When the weight average molecular weight of chitosan is less than 2,000, when the obtained chitosan derivative is used as a polymer surfactant (emulsifier), it is necessary to increase the blending amount in order to further stabilize the obtained emulsion. .. Further, if the molecular size of chitosan is too small, the permeability to the skin may be easily increased when used as a raw material for cosmetics. On the other hand, if the weight average molecular weight of chitosan is more than 1,000,000, the viscosity of the solution becomes too high, and handling when blended in cosmetics may be somewhat difficult.

The degree of deacetylation of chitosan is preferably 70 to 100%, more preferably 75 to 99%. If the degree of deacetylation of chitosan is less than 70%, the solubility in a solvent such as acetic acid may be slightly reduced. The degree of deacetylation of chitosan can be calculated from the titration amount obtained by performing colloidal titration. Specifically, a free amino group in the chitosan molecule is quantified by colloid titration with an aqueous solution of potassium polyvinyl sulfate using a toluidine blue solution as an indicator, and the degree of deacetylation of chitosan is determined. An example of a method for measuring the degree of deacetylation is shown below.

(1) Titration test Chitosan was added to a 0.5 mass% acetic acid aqueous solution so that the pure chitosan concentration was 0.5 mass%, and the chitosan was stirred and dissolved to make 100 g of 0.5 mass% chitosan / 0. Prepare a 5 mass% acetic acid aqueous solution. Next, 10 g of this solution and 90 g of ion-exchanged water are stirred and mixed to prepare a 0.05 mass% chitosan solution. Further, 50 mL of ion-exchanged water and about 0.2 mL of toluidin blue solution are added to 10 g of this 0.05 mass% chitosan solution to prepare a sample solution, which is titrated with a polyvinyl sulfate potassium solution (N / 400 PVSK). The titration rate is 2 to 5 ml / min, and the point at which the sample solution is held for 30 seconds or longer after the sample solution changes color from blue to purplish red is defined as the titration amount at the end point. The pure chitosan content means the mass of chitosan in the raw material chitosan sample. Specifically, it is the solid content mass obtained by drying the raw material chitosan sample at 105 ° C. for 2 hours.

(2) Blank test Perform the same titration test using ion-exchanged water instead of the 0.5% by mass chitosan / 0.5% by mass acetic acid aqueous solution used in the above titration test.

(3) Calculation of degree of acetylation X = 1/400 × 161 × f × (VB) / 1000
= 0.4025 x f x (V-B) / 1000
Y = 0.5 / 100-X
X: Mass of free amino group in chitosan (corresponding to mass of glucosamine residue)
Y: Mass of bound amino group in chitosan (corresponding to mass of N-acetylglucosamine residue)
f: Titer of N / 400 PVSK V: Titration of sample solution (mL)
B: Blank test titration (mL)
Deacetylation degree (%)
= (Free amino group) / {(Free amino group) + (Binding amino group)} × 100
= (X / 161) / (X / 161 + Y / 203) × 100
In addition, "161" is the molecular weight of the glucosamine residue, and "203" is the molecular weight of the N-acetylglucosamine residue.

(Acid modifier)
The acid modifier is a compound used as a chitosan modifier that reacts with the reactive functional group of chitosan (excluding the acylation modifier). The reactive functional group of chitosan that reacts with the acid denaturing agent is mainly a hydroxy group (-OH). Further, although it depends on the type of the acid denaturing agent and the reaction conditions, the reaction tends to be more likely in the order of the primary hydroxy group and the secondary hydroxy group. _{The amino group (-NH 2} ) may function as a reactive group depending on the reaction conditions and the like.

The acid modifier preferably has 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms. Examples of the acid denaturing agent include halogenated fatty acids and the like. Examples of halogenated fatty acids include chloroacetic acid (monochloroacetic acid), bromoacetic acid (monobromoacetic acid), 2-chloropropionic acid, 2-bromopropionic acid, 3-chloropropionic acid, 3-bromopropionic acid, 2-chlorobutanoic acid, and 2 −Bromobutanoic acid, 3-chlorobutanoic acid, 3-bromobutanoic acid, 4-chlorobutanoic acid, 4-bromobutanoic acid and the like can be mentioned. Of these, chloroacetic acid, 3-chloropropionic acid, and 4-chlorobutanoic acid are preferable. By using these halogenated fatty acids as an acid denaturing agent, a chitosan derivative having better solubility in the neutral to alkaline range can be obtained. These halogenated fatty acids can be used alone or in combination of two or more.

(Siloxane compound)
The siloxane compound used as a denaturing agent for chitosan is a compound represented by the following general formula (1).
ZZ-Y-Si (R ₁ ) _a {[-O-Si (R ₂ ) (R ₃ )] _b- R ₄ } _3-a ... (1)

In the general formula (1), Z represents a functional group capable of reacting with a reactive functional group of chitosan (mainly an amino group (-NH ₂ )). Specific examples of the functional group capable of reacting with the reactive functional group of chitosan include an epoxy group, a maleyl anhydride group, an amino group, a mercapto group, a vinyl group, a carbinol group, a carboxy group, an acryloyl group, a methacryloyl group and an isocyanate group. Examples thereof include a hydrosilyl group, a chloro group and a fluoro group. Of these, an epoxy group, a maleyl anhydride group, an amino group and a chloro group are preferable from the viewpoint of the reactivity of chitosan with the reactive functional group.

In the general formula (1), Y represents an alkylene group having 2 to 8 carbon atoms, which may have an oxygen atom, a nitrogen atom, or a sulfur atom. Among them, a divalent group represented by the following formulas (1a) to (1c) is preferable from the viewpoint of good reaction efficiency and the like. In addition, "*" in the following formulas (1a) to (1c) indicates the bonding position with "Z" and "Si" in the general formula (1).

In the general formula (1), R ₁ , R ₂ , R ₃ and R ₄ each independently have a monovalent organic group having 1 to 8 carbon atoms or a group represented by the following general formula (2). show.
-O-Si (R ₅ ) (R ₆ ) (R ₇ ) ... (2)
(In the general formula (2), R ₅ , R ₆ and R ₇ each independently represent a monovalent organic group having 1 to 8 carbon atoms).

Examples of the monovalent organic group having 1 to 8 carbon atoms represented by R ₁ , R ₂ , R ₃ , and R _{4 include an alkyl group and the like.} The alkyl group may be linear, branched, or cyclic. Specific examples of the alkyl group include direct methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl and the like. Alkyl groups of chain and branched chains; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl and the like can be mentioned. When a plurality of R _1s are present, the plurality of R _1s may be the same group or different groups.

In the general formula (2), the monovalent organic group having 1 to 8 carbon atoms represented by _{R 5} , R ₆ and R _{7 is represented by the above-mentioned R 1} , R ₂ , R ₃ and R ₄ . Examples thereof include groups similar to monovalent organic groups having 1 to 8 carbon atoms.

In the general formula (1), a represents an integer of 0 to 3. Among them, from the viewpoint of the reactivity of chitosan with the reactive functional group, a is preferably an integer of 1 to 3, preferably 2 or 3. Further, in the general formula (1), b represents an integer of 1 to 10. Among them, b is preferably an integer of 2 to 8, and more preferably an integer of 2 to 5.

As the siloxane compound, various commercially available grades can be used. Further, a siloxane compound synthesized according to a known method can also be used.

(Substituent introduction rate)
The introduction rate (A) of the first substituent derived from the acid modifier is preferably 0.3 to 1.5, more preferably 0.4 to 1.4, and 0.6 to 1 It is particularly preferable that it is 3.3. When the introduction rate (A) of the first substituent is less than 0.3, the solubility under neutral to alkaline conditions may be easily lowered. On the other hand, if the introduction rate (A) of the first substituent is more than 1.5, the obtained chitosan derivative may be colored or the yield may decrease, which may make production difficult. ..

The introduction rate (S) of the second substituent derived from the siloxane compound is preferably 0.01 to 0.4, more preferably 0.03 to 0.3, and 0.05 to 0. It is particularly preferably 25. If the introduction rate (S) of the second substituent is less than 0.01, the function as an emulsifier may be slightly reduced. On the other hand, if the introduction rate (S) of the second substituent is more than 0.4, it may be difficult to increase the introduction rate (A) of the first substituent. As a result, the solubility under neutral to alkaline conditions tends to decrease, and the function as an emulsifier may decrease slightly.

As used herein, the "substituent introduction rate (substituent introduction rate)" means the number of moles of substituents per mole of the pyranose ring constituting chitosan. The substituent introduction rate can be calculated from, for example, the ratio of nitrogen atoms derived from chitosan by elemental analysis of the chitosan derivative. Further, each degree of substitution may be calculated by analyzing the structure by NMR.

The value of the ratio (A / S) of the introduction rate (A) of the first substituent to the introduction rate (S) of the second substituent is 2.0 to 25.0, preferably 3.0. It is ~ 24.0, more preferably 4.0 to 23.0. The chitosan derivative of the present invention having an A / S value within the above range is a polymer surfactant (emulsion) capable of preparing an emulsifying composition (emulsion) having excellent emulsion stability in the neutral to alkaline range. It is useful as an emulsifier).

If the A / S value is less than 2.0, the introduction rate (A) of the first substituent is relatively too small, and the solubility under neutral to alkaline conditions decreases. , The function as an emulsifier is not exhibited. On the other hand, if the A / S value is more than 25.0, the introduction rate (S) of the second substituent is relatively too small, and therefore, as an emulsifier for finely dispersing oil such as silicone oil, for example. Function may not be exhibited.

<Manufacturing method of chitosan derivative>
The method for producing a chitosan derivative of the present invention is a method for producing the above-mentioned chitosan derivative, and comprises reacting a siloxane compound with chitosan to introduce a first substituent and a second substituent into chitosan. .. Hereinafter, the details of the method for producing the chitosan derivative of the present invention will be described.

(Reaction process)
The method for producing a chitosan derivative of the present invention includes, for example, a first reaction step and a second reaction step. In the first reaction step, the acid denaturing agent is brought into contact with chitosan, and the reactive functional group (mainly hydroxy group (-OH)) of chitosan is reacted with the acid denaturing agent to carry out acid denaturation, and the chitosan is subjected to the first substituent. Is the process of introducing. In the second reaction step, the siloxane compound is brought into contact with chitosan, and the reactive functional group of chitosan (mainly the amino group (-NH ₂ )) is combined with the reactive group of the siloxane compound (Z in the general formula (1)). This is a step of introducing a second substituent into chitosan by reacting the represented group).

The order of the reaction steps is not particularly limited, and the desired chitosan derivative can be obtained regardless of which of the first reaction step and the second reaction step is carried out first. Among them, it is preferable to carry out the first reaction step first and then the second reaction step, that is, to react chitosan with the acid denaturant and then react with the siloxane compound. With such an order, the yield of the chitosan derivative can be improved. Further, after the first reaction step is carried out, the obtained intermediate raw material may be taken out and vacuum dried, or the second reaction step may be carried out as it is without taking out.

In the first reaction step and the second reaction step, for example, chitosan is reacted with a modifier in a reaction solvent containing water and a water-soluble organic solvent. Examples of the water-soluble organic solvent include alcohols such as methanol, ethanol and isopropyl alcohol; ketones such as dimethyl ketone, methyl ethyl ketone and methyl isobutyl ketone; ethers such as dimethyl ether, diethyl ether, tetrahydrofuran and 1,2-dioxane; N- Methylformamide, N-methylacetamide, N-ethylformamide, N, N-dimethylformamide, N, N-diethylformamide, N-ethylacetamide, N, N-dimethylacetamide, N, N-diethylacetamide, N-methylpyrrolidone , N-ethylpyrrolidone and other amides; dimethylsulfoxide and other sulfoxides; and the like. Of these, methanol, ethanol, isopropyl alcohol, dimethyl ketone, and methyl ethyl ketone are preferable. These water-soluble organic solvents can be used alone or in combination of two or more.

The reaction temperature of the first reaction step is usually 0 to 80 ° C, preferably 20 to 70 ° C. The reaction time of the first reaction step depends on the reaction temperature, but is usually 1 to 24 hours, preferably 1 to 8 hours. The introduction rate of the first substituent can be controlled by appropriately setting the reaction temperature and the reaction time.

The reaction temperature of the second reaction step is usually 40 to 90 ° C, preferably 50 to 80 ° C. The reaction time of the second reaction step depends on the reaction temperature, but is usually 6 hours or more, preferably 10 hours or more. The introduction rate of the second substituent can be controlled by appropriately setting the reaction temperature and the reaction time.

After the reaction step, the desired chitosan derivative can be obtained by washing, purifying, drying and the like as necessary.

<O / W type emulsified composition>
The O / W type emulsified composition of the present invention (hereinafter, also simply referred to as “emulsified composition”) contains water, oil, and an emulsifier that disperses the oil in the form of emulsified droplets in water. The emulsifier is the above-mentioned chitosan derivative that functions as a polymer surfactant. That is, since the emulsified composition of the present invention is prepared with the above-mentioned chitosan derivative (emulsifier) having excellent emulsifying performance, fine emulsified droplets are formed and the emulsified stability is excellent. Therefore, the emulsified composition of the present invention is extremely useful as a cosmetic or the like, taking advantage of its safety and excellent emulsification stability.

_{Specifically, the median diameter (d 50} ) of the emulsified droplet in the emulsified composition is preferably 12.0 μm or less, more preferably 10.0 μm or less, and particularly preferably 8.0 μm or less. The lower limit of the median diameter (d ₅₀ ) of the emulsified droplet is not particularly limited, but it may be substantially 0.3 μm or more. The "median diameter (d ₅₀ )" in the present specification means a volume-based cumulative 50% particle diameter measured using a measuring device such as a laser diffraction particle size distribution measuring device.

The emulsified composition can be prepared according to a conventionally known method for preparing an emulsified composition, except that the above-mentioned chitosan derivative is used as an emulsifier. Examples of the oil include straight silicone oils such as dimethylpolysiloxane and methylphenylpolysiloxane; various modified silicone oils such as amino-modified silicone oil and alkyl-modified silicone oil; squalane; isopropyl myristate; perfluoropolyether; etc. Can be mentioned.

The chitosan derivative of the present invention can be used as, for example, a thickener, a dispersant, a surface modifier, a spreading agent, a protective colloidal agent, a water retaining agent, and the like, in addition to a polymer surfactant. Therefore, by containing the chitosan derivative of the present invention, in addition to the O / W type emulsified composition described above, for example, a wide range of articles such as cosmetics, paints, papermaking, fibers, building materials, civil engineering materials, foods, and pharmaceuticals. And materials are expected to be provided.

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. In addition, "part" in Examples and Comparative Examples is based on mass unless otherwise specified.

<Manufacturing of chitosan derivatives>
(1) Production of intermediate raw materials (Synthesis Example 1)
After dispersing 50 parts of chitosan (weight average molecular weight 400,000, deacetylation degree 91%, 16 mesh pass) in 440 parts of isopropyl alcohol (IPA), 150 parts of 30% sodium hydroxide aqueous solution was added and 10 parts were added. It was kept at ° C. or lower for 1 hour. Then, 65 parts of chloroacetic acid and 370 parts of IPA were added, and the mixture was reacted at 30 ° C. for 1 hour with stirring. Then, the reaction product was washed successively with hydrated methanol, hydrated methanol containing hydrochloric acid, hydrated IPA, and IPA, and vacuum dried at 50 ° C. to obtain an intermediate raw material.

(Synthesis Examples 2-5)
An intermediate raw material was obtained in the same manner as in Synthesis Example 1 described above, except that the formulations and reaction conditions shown in Table 1 were used.

(Synthesis Example 6)
After dispersing 50 parts of chitosan (weight average molecular weight 400,000, deacetylation degree 91%, 16 mesh path) in 440 parts of IPA, 150 parts of 30% sodium hydroxide aqueous solution was added and the temperature was 10 ° C. or lower for 1 hour. Retained. Next, 75 parts of 3-chloropropionic acid and 370 parts of IPA were added, and the introduction rate increased while confirming the introduction rate of the first substituent by 3-chloropropionic acid (acid denaturant) by elemental analysis under stirring. The reaction was continued until it stopped. Then, the reaction product was washed successively with hydrated methanol, hydrated methanol containing hydrochloric acid, hydrated IPA, and IPA, and vacuum dried at 50 ° C. to obtain an intermediate raw material.

(Synthesis Example 7)
After dispersing 50 parts of chitosan (weight average molecular weight 400,000, deacetylation degree 91%, 16 mesh path) in 440 parts of IPA, 150 parts of 30% sodium hydroxide aqueous solution was added and the temperature was 10 ° C. or lower for 1 hour. Retained. Next, 85 parts of 4-chlorobutanoic acid and 370 parts of IPA were added, and the introduction rate did not increase while confirming the introduction rate of the first substituent by 4-chlorobutanoic acid (acid denaturant) by elemental analysis under stirring. The reaction continued until. Then, the reaction product was washed successively with hydrated methanol, hydrated methanol containing hydrochloric acid, hydrated IPA, and IPA, and vacuum dried at 50 ° C. to obtain an intermediate raw material.

(2) Production of Chitosan Derivative (Example 1)
50 parts of the intermediate raw material, 450 parts of IPA, 350 parts of water, and 90 parts of the denaturant (siloxane compound) represented by the following formula (1-1) obtained in Synthesis Example 2 were charged into a reaction vessel, and the mixture was stirred at 70 ° C. The reaction was carried out for 10 hours. After cooling, the reaction product was washed successively with hydrous IPA and IPA, and vacuum dried at 50 ° C. to obtain a chitosan derivative.

(Examples 2 to 6)
A chitosan derivative was obtained in the same manner as in Example 1 described above, except that the formulations and reaction conditions shown in Table 2 were used.

(Example 7)
50 parts of the intermediate raw material, 550 parts of IPA, 250 parts of water, and 50 parts of the denaturant (siloxane compound) represented by the formula (1-1) obtained in Synthesis Example 6 were charged into the reaction vessel. While stirring, the introduction rate of the second substituent by the denaturant was confirmed by elemental analysis, and the reaction was continued until the introduction rate did not increase. Then, the reaction product was washed successively with hydrous IPA and IPA, and vacuum dried at 50 ° C. to obtain a chitosan derivative.

(Example 8)
A chitosan derivative was obtained in the same manner as in Example 7 described above, except that the intermediate raw material obtained in Synthesis Example 7 was used instead of the intermediate raw material obtained in Synthesis Example 6.

(Example 9)
The above-mentioned, except that the intermediate raw material obtained in Synthesis Example 4 was used instead of the intermediate raw material obtained in Synthesis Example 6 and the modifier (siloxane compound) represented by the following formula (1-2) was used. A chitosan derivative was obtained in the same manner as in Example 7.

(Comparative Example 1)
50 parts of the intermediate raw material, 450 parts of IPA, 350 parts of water, and 90 parts of the denaturant (siloxane compound) represented by the formula (1-1) obtained in Synthesis Example 1 were charged into a reaction vessel, and 10 parts at 70 ° C. under stirring. Reacted for time. After cooling, the reaction product was washed successively with hydrous IPA and IPA, and vacuum dried at 50 ° C. to obtain a chitosan derivative.

(Comparative Examples 2 to 6)
A chitosan derivative was obtained in the same manner as in Comparative Example 1 described above, except that the formulations and reaction conditions shown in Table 3 were used. In Table 3, "Ricaresin L-200" is a trade name of alkyl glycidyl ether manufactured by Shin Nihon Rika Co., Ltd. The structure of the siloxane compound used as the modifier is shown below. The chitosan used in Comparative Example 6 is the same as the chitosan used in Synthesis Examples 1 to 7 (weight average molecular weight 400,000, deacetylation degree 91%, 16 mesh path).

<Evaluation>
(Measurement and calculation of substituent introduction rate)
The chitosan derivative was elementally analyzed, and the substituent introduction rate (the number of moles of substituents per mole of the pyranose ring constituting chitosan) was calculated from the ratio of nitrogen atoms derived from chitosan. The results are shown in Table 4.

(Measurement of infrared absorption spectrum)
Measuring the infrared absorption spectrum of chitosan derivatives, whether absorption near 1,050cm ^-1 (derived from a siloxane bond (Si-O-Si)) , and 1,250cm absorption near ^-1 (Si-CH ₃ bond (Derived from) was confirmed. The results are shown in Table 4.

(Solubility in sodium carbonate aqueous solution)
A 1% aqueous dispersion of chitosan derivative was prepared. An equal amount of sodium carbonate as the chitosan derivative was added to the prepared aqueous dispersion and mixed, and the solubility of the chitosan derivative in the aqueous sodium carbonate solution was evaluated according to the evaluation criteria shown below. The results are shown in Table 4.
⊚: Dissolved transparently.
◯: Dissolved almost transparently.
Δ: Most of it was dissolved, but some remained undissolved.
X: Turbidity occurred and did not dissolve.

(Measurement of emulsified droplet diameter (median diameter (d ₅₀ )))
Mix 1 part of chitosan derivative, 0.5 part of sodium hydrogen carbonate, 98.5 parts of water, and ^{100 parts of dimethyl silicone oil (kinematic viscosity at 25 ° C.: 6 mm 2} / s) and use a dissolver at 2,000 rpm. An emulsified composition (emulsified liquid) was prepared by stirring for 3 minutes. _{The droplet diameter (median diameter d 50} ) of dimethyl silicone oil in the emulsion prepared using a laser diffraction particle size distribution measuring device was measured, and the emulsification performance of the chitosan derivative was evaluated according to the evaluation criteria shown below. The results are shown in Table 4.
⊚: The median diameter of the emulsified droplet was 8.0 μm or less.
◯: The median diameter of the emulsified droplet exceeded 8.0 μm and was 12.0 μm or less.
X: The median diameter of the emulsified droplet exceeded 12.0 μm.
XX: No emulsification was performed, and the diameter of the emulsified droplet could not be measured.

(Example 10)
1 part of the chitosan derivative obtained in Example 4, 1.0 part of sodium carbonate, 99.0 parts of water, and 100 parts of isopropyl myristate (manufactured by Tokyo Chemical Industry Co., Ltd.) were mixed and 2,000 rpm using a dissolver. An O / W type emulsified composition (emulsified liquid) was prepared by stirring for 3 minutes. _{The median diameter (d 50} ) of the emulsified droplet measured using the laser diffraction particle size distribution measuring device was 8.9 μm.

The chitosan derivative of the present invention is useful as an emulsifier for preparing an emulsifying composition such as a cosmetic.

Claims (9)

A first substituent derived from an acid denaturing agent and a second substituent derived from a siloxane compound represented by the following general formula (1) have been introduced into chitosan.
A chitosan derivative in which the value (A / S) of the ratio (A / S) of the introduction rate (A) of the first substituent to the introduction rate (S) of the second substituent is 2.0 to 25.0.
ZZ-Y-Si (R ₁ ) _a {[-O-Si (R ₂ ) (R ₃ )] _b- R ₄ } _3-a ... (1)
(In the general formula (1), Z represents a functional group capable of reacting with the reactive functional group of the chitosan, and Y may have an oxygen atom, a nitrogen atom, or a sulfur atom, and has 2 carbon atoms. Representing an alkylene group of ~ 8, R ₁ , R ₂ , R ₃ and R ₄ are independently monovalent organic groups having 1 to 8 carbon atoms or groups represented by the following general formula (2). , A indicates an integer of 0 to 3, and b indicates an integer of 1 to 10).
-O-Si (R ₅ ) (R ₆ ) (R ₇ ) ... (2)
(In the general formula (2), R ₅ , R ₆ and R ₇ each independently represent a monovalent organic group having 1 to 8 carbon atoms). The chitosan derivative according to claim 1, wherein the acid denaturing agent is a halogenated fatty acid. The chitosan derivative according to claim 2, wherein the halogenated fatty acid is at least one selected from the group consisting of chloroacetic acid, 3-chloropropionic acid, and 4-chlorobutanoic acid. The chitosan derivative according to any one of claims 1 to 3, which is used as a polymer surfactant. The method for producing a chitosan derivative according to any one of claims 1 to 4.
A method for producing a chitosan derivative, which comprises reacting the acid modifier and the siloxane compound with the chitosan to introduce the first substituent and the second substituent into the chitosan. The method for producing a chitosan derivative according to claim 5, wherein the siloxane compound is reacted after the acid denaturing agent is reacted with the chitosan. Contains water, oil, and an emulsifier that disperses the oil in the form of emulsified droplets in the water.
An O / W type emulsified composition in which the emulsifier is the chitosan derivative according to any one of claims 1 to 4. The O / W type emulsified composition according to claim 7, wherein the emulsified droplet has a median diameter (d _{50) of 12.0 μm or less.} A cosmetic containing the chitosan derivative according to any one of claims 1 to 4.