JP7365279B2 - Method for producing chitosan derivatives - Google Patents

Description

The present invention relates to a method for producing chitosan derivatives .

Low-molecular-weight surfactants, which are widely used in the fields of cosmetics, foods, and detergents, have high surfactant ability, but because they have a structure similar to lipid molecules, they are less irritating when penetrated into the skin. There are concerns. On the other hand, petroleum-derived polymer surfactants are difficult to take into the human body and can be said to be relatively safe, but they are not biocompatible and cannot be used in fields such as food emulsifiers. tends to be restricted. Therefore, surfactants made from polysaccharides derived from natural products are being actively developed.

For example, siloxane-modified polysaccharides obtained by grafting organopolysiloxanes onto polysaccharides can be used in film-forming cosmetics used for hair and skin, gas separation membranes, back coating agents for thermal transfer, and paints. It is useful as a component to be blended.

Note that emulsifiers used as raw materials for cosmetics are required to have high molecular weight and low permeability into the skin. For example, a chitosan derivative, which is obtained by grafting a long-chain fatty acid onto chitosan and is blended into cosmetics, has been proposed (Patent Document 1). Furthermore, siloxane-modified chitosan used as an emulsifier for preparing emulsions for cosmetics and the like has been proposed (Patent Document 2). Furthermore, a chitosan derivative for use as a polymeric surfactant, which is obtained by acylating a long-chain fatty acid grafted product of chitosan with a polyvalent fatty acid, has been proposed (Patent Document 3).

Japanese Patent Application Publication No. 2000-212203 JP2018-35306A Japanese Patent Application Publication No. 2005-213494

When the chitosan derivatives proposed in Patent Documents 1 and 2 are used as emulsifiers for cosmetics, it is thought that the weakly basic amino group functions as a dissociative group of chitosan. Therefore, in the neutral to alkaline pH range, chitosan derivatives and the like tend to precipitate and lose their function as emulsifiers. Furthermore, in the chitosan derivative proposed in Patent Document 3, the cationic properties of chitosan are weakened by acylating the amino groups of chitosan with a polyvalent fatty acid. However, the function as an emulsifier and the stability of the prepared emulsified composition were not yet sufficient.

The present invention has been made in view of the problems of the prior art, and its object is to create an emulsion composition that can be prepared by finely dispersing various oils in water. The 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 emulsion composition using this chitosan derivative, and a cosmetic.

That is, according to the present invention, the following chitosan derivatives are provided.
[1] A first substituent derived from an acylation 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 A chitosan derivative having a ratio (A/S) of the introduction rate (A) of the first substituent to the introduction rate (S) of 1.0 to 20.0.
Z-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 represents a group having 2 carbon atoms, which may have an oxygen atom, a nitrogen atom, or a sulfur atom. ~8 alkylene group, R ₁ , R ₂ , R ₃ , and R ₄ are each independently a monovalent organic group having 1 to 8 carbon atoms, or a group represented by the following general formula (2). (a represents an integer from 0 to 3, b represents an integer from 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 [1] above, wherein the acylation modifier is at least one selected from the group consisting of fatty acids, fatty acid anhydrides, polyvalent fatty acids, polyvalent fatty acid anhydrides, and fatty acid halides. .
[3] The chitosan derivative according to [2] above, wherein the polyvalent fatty acid anhydride is at least one selected from the group consisting of succinic anhydride, maleic anhydride, and glutaric anhydride.
[4] The chitosan derivative according to any one of [1] to [3] above, which is used as a polymeric surfactant.

Furthermore, 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 [1] to [4] above, wherein the acylation modifier and the siloxane compound are reacted with the chitosan, and the first substituent and A method for producing a chitosan derivative, comprising introducing the second substituent into the chitosan.
[6] The method for producing a chitosan derivative according to [5] above, wherein the chitosan is reacted with the siloxane compound and then the acylation modifier is reacted with the chitosan.

Moreover, according to the present invention, the O/W type emulsion composition and cosmetics shown below are provided.
[7] O containing water, oil, and an emulsifier that disperses the oil in the form of emulsified droplets in the water, wherein the emulsifier is the chitosan derivative according to any one of [1] to [4] above. /W type emulsion composition.
[8] The O/W emulsion composition according to [7] above, wherein the median diameter (d ₅₀ ) of the emulsified droplets is 12.0 μm or less.
[9] A cosmetic containing the chitosan derivative according to any one of [1] to [4] above.

According to the present invention, it is possible to provide a chitosan derivative with excellent emulsifying performance in the neutral to alkaline range, which can be used to prepare emulsified compositions 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 emulsion composition using this chitosan derivative, and a cosmetic.

<Chitosan derivative>
Embodiments of the present invention will be described below, 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 acylation modifier and a second substituent derived from a siloxane compound represented by the following general formula (1) are introduced into chitosan. The ratio (A/S) of the rate of introduction of the first substituent (A) to the rate of introduction of the second substituent (S) is 1.0 to 20.0. Hereinafter, details of the chitosan derivative of the present invention will be explained.

Z-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 represents a group having 2 carbon atoms, which may have an oxygen atom, a nitrogen atom, or a sulfur atom. ~8 alkylene group, R ₁ , R ₂ , R ₃ , and R ₄ are each independently a monovalent organic group having 1 to 8 carbon atoms, or a group represented by the following general formula (2). (a represents an integer from 0 to 3, b represents an integer from 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 cationic properties because it has an amino group that is a reactive group. The chitosan derivative of the present invention is produced by reacting an acylation modifier and a specific siloxane compound having a reactive functional group (hereinafter also referred to as "modifier") with chitosan, and then producing a chitosan derivative derived from each of these modifiers. It is formed by introducing the first substituent and the second substituent into chitosan. Furthermore, by controlling the ratio (A/S) of the rate of introduction of the first substituent (A) to the rate of introduction of the second substituent (S) within a specific range, chitosan's original cationic Appropriately changes the 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 when added to compositions such as cosmetics formulated in the neutral to alkaline range. Excellent emulsifying performance is demonstrated even when Furthermore, by controlling the ratio (A/S) of the rate of introduction of the first substituent (A) to the rate of introduction of the second substituent (S) within a predetermined range, The emulsifying performance within the range of 100 to 100% is better exhibited, and even oils that are relatively difficult to finely disperse in water (such as silicone oil) can be easily finely dispersed to prepare stable emulsions. be able to.

(chitosan)
Chitosan is a deacetylated product of chitin obtained from crustaceans and filamentous fungi, has moisturizing properties, anti-cholesterol effects, excellent safety, and has been put into practical use as a raw material for cosmetics and a functional food material. Chitosan is produced industrially and is available in various grades.

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 polymeric surfactant (emulsifier), it is necessary to increase the blending amount in order to further stabilize the obtained emulsion. . Furthermore, if the molecular size of chitosan is too small, its permeability into the skin may tend to increase when used as a raw material for cosmetics. On the other hand, if the weight average molecular weight of chitosan exceeds 1,000,000, the solution viscosity will become too high, which may make it somewhat difficult to handle when blended into cosmetics.

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 by colloid titration. Specifically, by using a toluidine blue solution as an indicator and colloid titration with an aqueous solution of potassium polyvinyl sulfate, free amino groups in chitosan molecules are quantified, 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 chitosan pure concentration was 0.5 mass%, and the chitosan was stirred and dissolved to obtain 100 g of 0.5 mass% chitosan/0.5 mass%. Prepare a 5% by 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% by mass chitosan solution. Furthermore, a sample solution is prepared by adding 50 mL of ion-exchanged water and about 0.2 mL of toluidine blue solution to 10 g of this 0.05% by mass chitosan solution, and titrated with polyvinyl potassium sulfate solution (N/400 PVSK). The titration rate is 2 to 5 ml/min, and the end point titration is the point at which the sample solution changes color from blue to reddish-purple and is maintained for 30 seconds or more. Note that the pure chitosan content means the mass of chitosan in the raw chitosan sample. Specifically, it is the solid content mass determined by drying a raw material chitosan sample at 105° C. for 2 hours.

(2) Blank test A similar titration test is performed 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 x 161 x f x (V-B)/1000
=0.4025×f×(V-B)/1000
Y=0.5/100-X
X: amount of free amino substrate in chitosan (corresponding to the mass of glucosamine residues)
Y: Amount of bound amino substrate in chitosan (corresponding to the mass of N-acetylglucosamine residues)
f: Titer of N/400PVSK V: Titration amount of sample solution (mL)
B: Blank test titer (mL)
Deacetylation degree (%)
= (Free amino group) / {(Free amino group) + (Bound amino group)} x 100
=(X/161)/(X/161+Y/203)×100
Note that "161" is the molecular weight of the glucosamine residue, and "203" is the molecular weight of the N-acetylglucosamine residue.

(acylation modifier)
Acylation modifiers are compounds that are used as modifiers for chitosan and react with reactive functional groups of chitosan. The reactive functional group of chitosan is mainly an amino group (-NH ₂ ), and depending on the reaction conditions, a hydroxyl group (-OH) may function as a reactive group. Examples of the acylation modifier include fatty acids, fatty acid anhydrides, polyvalent fatty acids, polyvalent fatty acid anhydrides, fatty acid halides, and the like. These acylation modifiers can be used alone or in combination of two or more. The acylation modifier preferably has 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms. The polyvalent fatty acids and polyvalent fatty acid anhydrides are preferably divalent or trivalent, and more preferably divalent. As the acylation modifier, fatty acid anhydrides and polyvalent fatty acid anhydrides are preferred from the viewpoint of reactivity.

Examples of fatty acid anhydrides include acetic anhydride, propionic anhydride, butyric anhydride, valeric anhydride, isovaleric anhydride, hexanoic anhydride, and the like. Examples of polyvalent fatty acid anhydrides include malonic anhydride, succinic anhydride, maleic anhydride, glutaric anhydride, adipic anhydride, and the like. As the acylation modifier, from the viewpoint of charge control, polyvalent fatty acid anhydrides such as at least one of succinic anhydride, maleic anhydride, and glutaric anhydride are preferred. Furthermore, by using at least one of polyvalent fatty acid anhydrides such as succinic anhydride, maleic anhydride, and glutaric anhydride as an acylation modifier, chitosan has better solubility in the neutral to alkaline range. It can be a derivative.

(siloxane compound)
The siloxane compound used as a modifier for chitosan is a compound represented by the following general formula (1).
Z-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 that can react with a reactive functional group (mainly an amino group (-NH ₂ )) of chitosan. Specific examples of functional groups that can react with the reactive functional groups of chitosan include epoxy groups, maleyl anhydride groups, amino groups, mercapto groups, vinyl groups, carbinol groups, carboxy groups, acryloyl groups, methacryloyl groups, isocyanate groups, Examples include hydrosilyl group, chloro group, and fluoro group. Among these, from the viewpoint of reactivity with the reactive functional group of chitosan, epoxy groups, maleyl anhydride groups, amino groups, and chloro groups are preferred.

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

In general formula (1), R ₁ , R ₂ , R ₃ , and R ₄ each independently represent 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. The alkyl group may be linear, branched, or cyclic. Specific examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, etc. Chain and branched alkyl groups; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl; and the like. In addition, when a plurality of R _1s exist, the plurality of R _1s may be the same group or different groups.

In 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 R ₁ , R ₂ , R ₃ , and R ₄ described above. The same groups as the monovalent organic group having 1 to 8 carbon atoms can be mentioned.

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

As the siloxane compound, various commercially available grades can be used. Furthermore, 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 acylation modifier is preferably from 0.3 to 1.0, more preferably from 0.4 to 0.95, and more preferably from 0.5 to 0.95. Particularly preferred is 0.9. If the introduction rate (A) of the first substituent is less than 0.3, the solubility under conditions in the neutral to alkaline range may tend to decrease. On the other hand, if the introduction rate (A) of the first substituent group is more than 1.0, the obtained chitosan derivative may be colored or the yield may decrease, making 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 0.38, and more preferably 0.05 to 0. 35 is particularly preferred. 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 second substituent introduction rate (S) is more than 0.4, it may be difficult to increase the first substituent introduction rate (A). As a result, the solubility tends to decrease under conditions in the neutral to alkaline range, and the function as an emulsifier may deteriorate somewhat.

The term "substituent introduction rate (substituent introduction rate)" as used herein means the number of moles of substituents per mole of pyranose rings constituting chitosan.
The substituent introduction rate can be calculated, for example, by elemental analysis of a chitosan derivative and from the proportion of nitrogen atoms derived from chitosan. Furthermore, each degree of substitution may be calculated by analyzing the structure by NMR.

The ratio (A/S) of the introduction rate (A) of the first substituent to the introduction rate (S) of the second substituent is 1.0 to 20.0, preferably 2.0. -18.0, more preferably 3.0-16.0. The chitosan derivative of the present invention having an A/S value within the above range is a polymeric surfactant (emulsion) capable of preparing an emulsion composition (emulsion) with excellent emulsion stability in the neutral to alkaline range. It is useful as an emulsifier).

If the A/S value is less than 1.0, the introduction rate (A) of the first substituent is relatively too small, resulting in a decrease in solubility under conditions in the neutral to alkaline range. , it does not function as an emulsifier. On the other hand, if the A/S value is more than 20.0, the introduction rate (S) of the second substituent is relatively too small, so it can be used as an emulsifier for finely dispersing oil such as silicone oil. may not function properly.

<Production 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, in which a first substituent and a second substituent are introduced into chitosan by reacting an acylation modifier and a siloxane compound with chitosan. including doing. Hereinafter, details of the method for producing a chitosan derivative of the present invention will be explained.

(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, a siloxane compound is brought into contact with chitosan, and a reactive group (represented by Z in general formula (1)) of the siloxane compound is attached to a reactive functional group (mainly an amino group (-NH ₂ )) of chitosan. This is a step of introducing a second substituent into chitosan by reacting the substituent group). In addition, in the second reaction step, the acylation modifier is brought into contact with chitosan, and the reactive functional groups (mainly amino groups (-NH ₂ )) of chitosan are reacted with the acylation modifier. This is the step of introducing a substituent.

The order of the reaction steps is not particularly limited, and the desired chitosan derivative can be obtained by performing either the first reaction step or the second reaction step first.
Among these, it is preferable to first perform the first reaction step and then perform the second reaction step, that is, to react the chitosan with the siloxane compound and then react with the acylation modifier. By using such an order, the yield of chitosan derivatives can be improved. Furthermore, after performing the first reaction step, the obtained intermediate raw material may be taken out and dried under vacuum, but the second reaction step may be performed without taking it out.

In the first reaction step and the second reaction step, for example, chitosan and a modifier are reacted in a reaction solvent containing water and a water-soluble organic solvent. Examples of water-soluble organic solvents 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; Methylformamide, N-methylacetamide, N-ethylformamide, N,N-dimethylformamide, N,N-diethylformamide, N-ethylacetamide, N,N-dimethylacetamide, N,N-diethylacetamide, N-methylpyrrolidone , amides such as N-ethylpyrrolidone; sulfoxides such as dimethyl sulfoxide; and the like. Among these, methanol, ethanol, isopropyl alcohol, dimethyl ketone, and methyl ethyl ketone are preferred. These water-soluble organic solvents can be used alone or in combination of two or more.

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

The reaction temperature in the second reaction step is usually 0 to 70°C, preferably 10 to 50°C. The reaction time of the second reaction step depends on the reaction temperature, but is usually 1 to 24 hours, preferably 1 to 8 hours. By appropriately setting the reaction temperature and reaction time, the introduction rate of the first substituent can be controlled.

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

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

Specifically, the median diameter (d ₅₀ ) of emulsified droplets in the emulsified composition is preferably 12.0 μm or less, more preferably 10.0 μm or less, particularly preferably 8.0 μm or less. The lower limit of the median diameter (d ₅₀ ) of the emulsified droplets is not particularly limited, but it may be substantially 0.3 μm or more. In addition, the "median diameter ( _d50 )" in this specification means the 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 for using the above-mentioned chitosan derivative 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; 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 colloid agent, a water retention agent, and the like in addition to a polymeric surfactant. Therefore, by containing the chitosan derivative of the present invention, in addition to the above-mentioned O/W type emulsion composition, a wide range of products such as cosmetics, paints, paper manufacturing, fibers, building materials, civil engineering materials, foods, and medicines can be used. They are expected to provide materials and materials.

Hereinafter, the present invention will be specifically explained based on Examples, but the present invention is not limited to these Examples. Note that "parts" in Examples and Comparative Examples are based on mass unless otherwise specified.

<Production of chitosan derivative>
(1) Production of intermediate raw materials (Synthesis Example 1)
50 parts of chitosan (weight average molecular weight 400,000, degree of deacetylation 91%, 16 mesh pass), 600 parts of isopropyl alcohol (IPA), 200 parts of water, and a modifier represented by the following formula (1-1) ( 15 parts of siloxane compound) were charged into a reaction vessel, and the mixture was reacted at 70°C for 10 hours with stirring. After cooling, the reaction product was sequentially washed with water-containing IPA and IPA, and vacuum dried at 50° C. to obtain an intermediate raw material.

(Synthesis examples 2 to 10)
An intermediate raw material was obtained in the same manner as in Synthesis Example 1 above, except that the formulation and reaction conditions shown in Table 1 were used. In Table 1, "Recaresin L-200" is the trade name of an alkyl glycidyl ether manufactured by Shin Nihon Rika Co., Ltd. Moreover, the structure of the siloxane compound used as a modifier is shown below.

(2) Production of chitosan derivative (Example 1)
50 parts of the intermediate raw material obtained in Synthesis Example 1, 400 parts of IPA, 400 parts of water, and 89 parts of succinic anhydride (manufactured by Junsei Kagaku Co., Ltd.) were charged into a reaction vessel, and reacted at 20° C. for 1 hour with stirring. After cooling, the reaction product was washed successively with water-containing 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 above, except that the formulation and reaction conditions shown in Table 2 were used.

(Example 7)
50 parts of the intermediate raw material obtained in Synthesis Example 2, 400 parts of IPA, 400 parts of water, and 87 parts of maleic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) were charged into a reaction vessel. While stirring, the reaction was continued until the introduction rate stopped increasing, while confirming the introduction rate of the first substituent by the acylation modifier (maleic anhydride) by elemental analysis. Thereafter, the reaction product was sequentially washed with water-containing IPA and IPA, and vacuum dried at 50°C to obtain a chitosan derivative.

(Examples 8 to 16)
A chitosan derivative was obtained in the same manner as in Example 7 above, except that the formulations shown in Table 3 were used.

(Comparative example 1)
50 parts of the intermediate raw material obtained in Synthesis Example 5, 400 parts of IPA, 400 parts of water, and 89 parts of succinic anhydride (manufactured by Junsei Kagaku Co., Ltd.) were charged into a reaction vessel, and reacted at 30° C. for 3 hours with stirring. After cooling, the reaction product was washed successively with water-containing IPA and IPA, and vacuum dried at 50°C to obtain a chitosan derivative.

(Comparative Examples 2 to 7)
A chitosan derivative was obtained in the same manner as in Comparative Example 1 above, except that the formulation and reaction conditions shown in Table 4 were used. The chitosan used in Comparative Example 6 is the same as the chitosan used in Synthesis Examples 1 to 10 (weight average molecular weight 400,000, degree of deacetylation 91%, 16 mesh pass).

<Evaluation>
(Measurement and calculation of substituent introduction rate)
The chitosan derivative was subjected to elemental analysis, and the substituent introduction rate (the number of moles of substituents per mole of pyranose rings constituting chitosan) was calculated from the proportion of nitrogen atoms derived from chitosan. The results are shown in Table 5.

(Measurement of infrared absorption spectrum)
The infrared absorption spectrum of the chitosan derivative was measured, and the presence or absence of absorption near 1,050 cm ^-1 (derived from siloxane bonds (Si-O-Si)) and absorption near 1,250 cm ^-1 (derived from Si-CH ₃ bonds) were determined. The presence or absence of (derived from) was confirmed. The results are shown in Table 5.

(Solubility in sodium carbonate aqueous solution)
A 1% aqueous dispersion of a chitosan derivative was prepared. An equivalent amount of sodium carbonate to the chitosan derivative was added to the prepared aqueous dispersion and mixed, and the solubility of the chitosan derivative in the sodium carbonate aqueous solution was evaluated according to the evaluation criteria shown below. The results are shown in Table 5.
◎: Dissolved transparently.
○: Dissolved almost transparently.
Δ: Most of the solution was dissolved, but some remained undissolved.
x: Turbidity occurred and no dissolution occurred.

(Measurement of emulsion droplet diameter (median diameter (d ₅₀ )))
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) were mixed, and the mixture was heated at 2,000 rpm using a dissolver. , and stirred for 3 minutes to prepare an emulsion composition (emulsion). The droplet diameter (median diameter d ₅₀ ) of dimethyl silicone oil in the prepared emulsion was measured using a laser diffraction particle size distribution analyzer, and the emulsification performance of the chitosan derivative was evaluated according to the evaluation criteria shown below. The results are shown in Table 5.
◎: The median diameter of the emulsified droplets was 8.0 μm or less.
Good: The median diameter of the emulsified droplets exceeded 8.0 μm and was 12.0 μm or less.
×: The median diameter of the emulsified droplets exceeded 12.0 μm.
XX: Emulsification did not occur and the diameter of emulsified droplets could not be measured.

(Example 17)
1 part of the chitosan derivative obtained in Example 2, 1.0 part of sodium carbonate, 99.0 parts of water, and 100 parts of isopropyl myristate (manufactured by Tokyo Kasei Kogyo Co., Ltd.) were mixed, and the mixture was heated at 2,000 rpm using a dissolver. , and stirred for 3 minutes to prepare an O/W emulsion composition (emulsion). The median diameter (d ₅₀ ) of the emulsified droplets measured using a laser diffraction particle size distribution analyzer was 8.5 μm.

The chitosan derivative of the present invention is useful as an emulsifier for preparing emulsified compositions such as cosmetics.

Claims (4)

A first substituent derived from an acylation modifier and a second substituent derived from a siloxane compound represented by the following general formula (1) are introduced into chitosan,
the acylation modifier is one selected from the group consisting of fatty acids, fatty acid anhydrides, polyvalent fatty acids, polyvalent fatty acid anhydrides, and fatty acid halides;
Production of a chitosan derivative in which 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 18.0. A method,
Reacting the acylation modifier and the siloxane compound with the chitosan in a reaction solvent containing water and isopropyl alcohol, respectively , to introduce the first substituent and the second substituent into the chitosan. including;
A method for producing a chitosan derivative , which comprises reacting the chitosan with the siloxane compound and then reacting the acylation modifier .
Z-Y-Si(R ₁ ) _a {[-O-Si(R ₂ )(R ₃ )] _b -R ₄ } _3-a ...(1)
(In the general formula (1), Z is 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, an isocyanate group, a hydrosilyl group, a chloro group, or represents a fluoro group, Y represents a divalent group represented by any of the following formulas (1a) to (1c), and R ₁ , R ₂ , R ₃ , and R ₄ are each independently, represents an alkyl group having 1 to 8 carbon atoms or a group represented by the following general formula (2), a represents an integer of 0 to 3, and b represents an integer of 1 to 10)

("*" in the above formulas (1a) to (1c) indicates the bonding position with "Z" and "Si" in general formula (1))
-O-Si(R ₅ )(R ₆ )(R ₇ )...(2)
(In the general formula (2), R ₅ , R ₆ , and R ₇ each independently represent an alkyl group having 1 to 8 carbon atoms) The method for producing a chitosan derivative according to claim 1, wherein the introduction rate (A) of the first substituent is 0.6 to 0.9 mol per 1 mol of pyranose rings constituting the chitosan. The method for producing a chitosan derivative according to claim 1 or 2, wherein the polyvalent fatty acid anhydride is succinic anhydride, maleic anhydride, or glutaric anhydride . The method for producing a chitosan derivative according to any one of claims 1 to 3, wherein the chitosan derivative is used as a polymeric surfactant.