Thickening composition and cosmetic composition

Abstract

To provide a thickening composition which simultaneously achieves both a refreshing tactile when applied to the skin and a thickening effect and a cosmetic composition containing the same.SOLUTION: There is provided a thickening composition comprising a component (a) and a component (b). The component (a) is a polyamino acid derivative containing a repeating unit represented by the following general formula (1) and the component (b) is a compound having a hydrophobic group. (In the formula, R1 contains at least a hydrocarbon group having 3 to 22 carbon atoms, and R2 contains at least a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. n and m represent the number of moles of α- or β-polyaspartic acid monomer units A-U and B-U in the molecule, respectively. In the polyamino acid derivative, the bonding form of the monomer unit A-U and the monomer unit B-U may be any of a random form, a blocked form or a tapered form.)SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a thickening composition and a cosmetic composition. [Background technology]

[0002] Carbomer, a polyacrylic acid-based thickener, is the most widely used cosmetic thickener on the market. Carbomer has features not found in other thickeners, including extremely high viscosity and a refreshing feel when applied to the skin. Polyaspartic acid has a similar chemical structure to polyacrylic acid and may be able to exhibit similar functions. In addition, because it is biodegradable, it is expected to be an alternative material with less environmental impact. For example, a nonionic polyamino acid derivative has been reported that does not lose its thickening or foaming effect even in the presence of salt (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4546158 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the polyamino acid derivative of Patent Document 1 has a problem in that the thickening effect is insufficient compared to existing thickeners.

[0005] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a thickening composition and a cosmetic composition containing the same, which exhibit thickening properties due to hydrophobic-hydrophobic interactions caused by long-chain alkyl groups in the side chains of a polyamino acid derivative, and which, by using the same in combination with another compound having a hydrophobic group, simultaneously achieves both a refreshing feel when applied to the skin and a thickening effect. [Means for solving the problem]

[0006] The present disclosure includes the following embodiments [1] to

[10] . [1] A thickening composition comprising component (a) and component (b), The component (a) is a polyamino acid derivative containing a repeating unit represented by the following general formula (1): A thickening composition, wherein the component (b) is a compound having a hydrophobic group. [ka] (In the formula, R1 contains at least a hydrocarbon group having 3 to 22 carbon atoms, and R2 contains at least a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. n and m respectively represent the number of moles of α-type or β-type polyaspartic acid monomer units AU and BU in the molecule. In the polyamino acid derivative, the bonding form of the monomer units AU and BU may be any of random, block, and tapered.) [2] The thickening composition according to [1], wherein the component (a) is a polyamino acid derivative containing a repeating unit represented by the following general formula (2): [ka] (In the formula, R1 contains at least a hydrocarbon group having 3 to 22 carbon atoms, and R2 contains at least a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. n and m respectively represent the number of moles of α-type or β-type polyaspartic acid monomer units AU and BU in the molecule, and l represents the number of moles of succinimide monomer units CU. l / (n+m) is 0 / 100 to 20 / 80. Crosslink-U represents a crosslinked portion. The wavy line of the crosslinked portion represents the crosslinked site. o represents the number of moles of Crosslink-U. o / (n+m) is 0 / 100 to 10 / 90. In the polyamino acid derivative, the bonding form of the monomer units AU, BU, CU, and Crosslink-U may be any of random, block, and tapered.) [3] The thickening composition according to [2], wherein R1 in the general formula (2) represents a hydrocarbon group having 3 to 22 carbon atoms, and R2 in the general formula (2) represents a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. [4] The thickening composition according to any one of [1] to [3], wherein the hydrophobic group in the component (b) is a hydrocarbon group having 4 to 22 carbon atoms. [5] The thickening composition according to any one of [1] to [4], wherein the component (b) is a hydrophobically modified cellulose derivative. [6] The thickening composition according to any one of [1] to [5], wherein R2 in the general formula (1) represents a hydroxyalkyl group having 2 to 6 carbon atoms. [7] The thickening composition according to any one of [1] to [6], wherein, in the general formula (1), the molar ratio, n / m, of the monomer units AU and BU is 40 / 60 to 60 / 40. [8] The thickening composition according to any one of [1] to [7], wherein the amount of crosslinking of the polyamino acid derivative is 0.1 to 2.0 mol %. [9] The thickening composition of claim 1 or 2, further comprising water.

[10] A cosmetic composition comprising the thickening composition according to any one of [1] to [9] and a cosmetic active ingredient. Effect of the Invention

[0007] According to the present invention, a thickening composition and a cosmetic composition containing the same can be provided, which exhibit thickening properties due to hydrophobic-hydrophobic interactions caused by long-chain alkyl groups on the side chains of a polyamino acid derivative, while by using the same in combination with a resin having another hydrophobic group, simultaneously realize both a refreshing feel when applied to the skin and a thickening effect. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram used to explain the mechanism of thickening of a polyamino acid derivative according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present invention will be described in more detail below. Note that the present invention is not limited to the following embodiments.

[0010] "~" means greater than or equal to the value before the "~", and less than or equal to the value after the "~".

[0011] (Thickening composition) A thickening composition according to one embodiment of the present invention (thickening composition according to the present embodiment) contains component (a) and component (b). Component (a) is a polyamino acid derivative containing a repeating unit represented by the following general formula (1), and component (b) is a compound having a hydrophobic group. Component (a) may contain a unit other than the repeating unit represented by the following general formula (1). Component (a) may be composed of a repeating unit represented by the following general formula (1). [ka]

[0012] In the above general formula (1), R1 contains at least a hydrocarbon group having 3 to 22 carbon atoms, and R2 contains at least a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. n and m respectively represent the number of moles of α-type or β-type polyaspartic acid monomer units AU and BU in the molecule. In the polyamino acid derivative, the bonding form of the monomer units AU and BU may be any of random, block, and tapered.

[0013] <Component (a)> The polyamino acid derivative represented by the above general formula (1) according to this embodiment is a monoamine-modified polyaspartic acid derivative obtained by ring-opening polysuccinimide (PSI) using a monoamine.

[0014] R1 in the general formula (1) preferably represents a hydrocarbon group having 3 to 22 carbon atoms. R2 in the general formula (1) preferably represents a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom.

[0015] In the above general formula (1), R1 preferably represents a hydrocarbon group having 3 to 18 carbon atoms. Examples of the hydrocarbon group having 3 to 18 carbon atoms of R1 in general formula (1) include hydrophobic saturated or unsaturated hydrocarbon groups. Specific examples of R1 include linear alkyl groups such as propyl group, butyl group, pentyl group, hexyl group, octyl group, dodecyl group, and octadecyl group; branched alkyl groups such as isopropyl group, isobutyl group, isopentyl group, and isohexyl group; cycloalkyl groups such as cyclobutyl group, cyclopentyl group, and cyclohexyl group; cycloalkylalkyl groups such as cyclobutylmethyl group, cyclopentylmethyl group, cyclohexylmethyl group, cyclobutylethyl group, cyclopentylethyl group, cyclohexylethyl group, cyclobutylpropyl group, cyclopentylpropyl group, cyclohexylpropyl group, cyclobutylbutyl group, cyclopentylbutyl group, and cyclohexylbutyl group; and alkenyl groups such as propenyl group, butenyl group, pentenyl group, hexenyl group, and oleyl group. In the above general formula (1), R1 is preferably a group selected from the group consisting of a hexyl group, an octyl group, a decyl group, a dodecyl group, a tetradecyl group, and an octadecyl group. In the above general formula (1), R1 is preferably a straight-chain alkyl group such as a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a dodecyl group, or an octadecyl group.

[0016] The hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom as R2 in the above general formula (1) includes hydrophilic saturated or unsaturated hydrocarbon groups which may contain N, O, S or the like.Specific examples of R2 include hydroxyalkyl groups such as a hydroxymethyl group, a hydroxyethyl group, a hydroxypropyl group, a hydroxybutyl group, a hydroxypentyl group, a hydroxyhexyl group, a hydroxyheptyl group, and a hydroxyoctyl group; dialkylamino groups such as a dimethylamino group, a diethylamino group, a dipropylamino group, and a dibutylamino group; an azapropyl group, an azabutyl group, an azapentyl group, an azahexyl group, an N,N-dimethylaminobutyl group, an N,N-dimethylaminopropyl group, and an N,N-dimethylaminoethyl group. azaalkyl groups such as an N,N-dimethylaminomethyl group, an N,N-diethylaminobutyl group, an N,N-diethylaminopropyl group, an N,N-diethylaminoethyl group, and an N,N-diethylaminomethyl group; azaalkenyl groups such as an azapropenyl group, an azabutenyl group, an azapentenyl group, an azahexenyl group, an N,N-dimethylaminopropenyl group, an N,N-dimethylaminobutenyl group, an N,N-dimethylaminohexenyl group, and an N,N-diethylaminopropenyl group; an oxaethyl group, an oxapropyl group, an oxabutyl group, an oxyl group, an oxalkenyl group, and an oxalyl group; oxaalkyl groups such as oxapentyl, oxahexyl, oxaheptyl, and oxaoctyl; oxaalkylenyl groups such as oxapropenyl, oxabutenyl, oxapentenyl, oxahexenyl, oxaheptenyl, and oxaoctenyl; thioalkyl groups such as thiobutyl, thiopentyl, thiohexyl, thioheptyl, and thiooctyl; thioalkenyl groups such as thiopentenyl, thiohexenyl, thioheptenyl, and thiooctenyl; hydroxyethoxyethyl, hydroxyethoxypropenyl, alkoxyalkyl groups such as a methoxyethoxyethyl group, a methoxyethoxypropyl group, a methoxyethoxybutyl group, a methoxypropoxyethyl group, a methoxypropoxypropyl group, a methoxypropoxybutyl group, etc.; and dihydroxyalkyl groups such as a dihydroxyethyl group, a dihydroxypropyl group, a dihydroxybutyl group, etc.

[0017] In the above general formula (1), R2 is preferably a group selected from the group consisting of an N,N-dimethylaminopropyl group, an N,N-diethylaminopropyl group, a hydroxymethyl group, a hydroxyethyl group, a hydroxypropyl group, a hydroxybutyl group, a hydroxypentyl group, a hydroxyethoxyethyl group, a methoxymethyl group, a methoxyethyl group, a methoxypropyl group, a methoxybutyl group, a methoxypentyl group, an ethoxymethyl group, an ethoxyethyl group, an ethoxypropyl group, an ethoxybutyl group, an ethoxypentyl group, and a dihydroxypropyl group.

[0018] R2 in the above general formula (1) is preferably a hydrocarbon group having 1 to 20 carbon atoms which may contain an oxygen atom. Examples of the hydrocarbon group having 1 to 20 carbon atoms which may contain an oxygen atom include the above specific examples of hydrophilic saturated or unsaturated hydrocarbon groups which may contain an oxygen atom.

[0019] In the above general formula (1), R2 more preferably represents a hydroxyalkyl group having 2 to 6 carbon atoms. Examples of the hydroxyalkyl group having 2 to 6 carbon atoms include a hydroxyethyl group, a hydroxypropyl group, a hydroxybutyl group, a hydroxypentyl group, and a hydroxyhexyl group.

[0020] R1 in the general formula (1) contains at least a hydrocarbon group having 3 to 22 carbon atoms, and may further contain a substituent other than the hydrocarbon group having 3 to 22 carbon atoms. Specific examples of the substituent other than the hydrocarbon group having 3 to 22 carbon atoms include an alicyclic hydrocarbon group, an aromatic hydrocarbon group, a hydroxyl group, a carboxyl group, and an amino group. For example, R1 is a polyoxyalkylene group and a hydrocarbon group R having 3 to 22 carbon atoms. 11 and the like.

[0021] -(C n H 2n O) m -R 11 (x) In the formula (x), n is 2 to 10, and preferably 2 to 4. m is 1 to 30, and preferably 1 to 10. R 11 is a hydrocarbon group having 3 to 22 carbon atoms, and preferably a hydrocarbon group having 3 to 18 carbon atoms. Preferred embodiments of the hydrocarbon group having 3 to 18 carbon atoms are the same as the hydrocarbon group having 3 to 18 carbon atoms for R1 described below. As a specific example of the group represented by the above formula (x), R1 may be a group represented by the formula (x1) in which a polyoxyethylene group and an octyl group are bonded.

[0022] -(C2H4O) m -C8H 17 (x1) The m in the formula (x1) has the same meaning as the m in the formula (x) above.

[0023] R2 in the general formula (1) contains at least a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, and may further contain a substituent other than the hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. Specific examples of the substituent other than the hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom include celluloses, polysaccharides, etc. For example, R2 may be a group formed by dehydration condensation between a hydroxyl group of a hydroxyalkyl group and a part of a hydroxyl group of cellulose. A specific example of such a group is a group represented by formula (y) formed by dehydration condensation between a hydroxypropyl group and a part of a hydroxyl group of cellulose.

[0024] -(C3H6O)-(C6H 10 O5) n (y)

[0025] The polyamino acid derivative represented by the above general formula (1) according to this embodiment has α-type or β-type polyaspartic acid monomer units AU and BU in the molecule, and the molar ratio of the monomer units AU and BU (AU:BU) is n:m. n / m is preferably 40 / 60 to 60 / 40, more preferably 45 / 55 to 60 / 40, and even more preferably 50 / 50 to 55 / 45. When n / m is within this range, the compatibility with water and the thickening property are excellent. The bond form of the monomer units AU and BU is preferably linear from the viewpoint of achieving both water solubility and thickening effect of the polyamino acid derivative.

[0026] In the nonionic polyamino acid derivative of this embodiment, the monomer units AU and BU are structural units derived from hydrophobic amine A and hydrophilic amine B, respectively (described in detail in the synthesis method described later). The number of moles of each structural unit can be adjusted by the amount of each raw material used in the synthesis. For example, in the synthesis method described later, it can be prepared by using the blending ratio of polysuccinimide (PSI) and monoamine, the blending ratio of various monoamines, etc. The actual composition of each monomer unit AU and BU in the obtained nonionic polyamino acid derivative is 1 It can be calculated from HNMR.

[0027] The polyamino acid derivative represented by the above general formula (1) according to this embodiment may be a polyamino acid derivative represented by the following general formula (2), or may be a polyamino acid derivative represented by the following general formula (3).

[0028] [ka]

[0029] In the above general formula (2), R1 contains at least a hydrocarbon group having 3 to 22 carbon atoms, and R2 contains at least a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. n and m respectively represent the number of moles of α-type or β-type polyaspartic acid monomer units AU and BU in the molecule, and l represents the number of moles of succinimide monomer units CU. l / (n+m) is 0 / 100 to 20 / 80. Crosslink-U represents a crosslinked portion. The wavy line of the crosslinked portion represents the crosslinked position. o represents the number of moles of Crosslink-U. o / (n+m) is 0 / 100 to 10 / 90. In the polyamino acid derivative, the bonding form of the monomer units AU, BU, CU, and Crosslink-U may be any of random, block, and tapered. l and o do not have to be 0 at the same time.

[0030] The preferred embodiments of R1, R2, n, and m in the above general formula (2) are the same as the preferred embodiments of R1 and R2 in the above general formula (1).

[0031] The polyamino acid derivative represented by the above general formula (2) according to this embodiment has α-type or β-type polyaspartic acid monomer units AU, BU, and CU in the molecule, and the molar ratio of the monomer units AU, BU, and CU (AU:BU:CU) is n:m:l. n / m is preferably 40 / 60 to 60 / 40, more preferably 45 / 55 to 60 / 40, and even more preferably 50 / 50 to 55 / 45. When n / m is in this range, compatibility with water and thickening properties are excellent. (n+m) / l is preferably 85 / 15 to 100 / 0, and more preferably 95 / 5 to 100 / 0. 1=0 may also be used. The bonding form of the monomer units AU, BU, and CU is preferably linear from the viewpoint of achieving both water solubility and thickening effect of the polyamino acid derivative. o / (n+m) may be 0 / 100 to 5 / 95, or may be 0 / 100 to 2 / 98. o may be 0. o / (n+m) may be 0.15 / 99.85 to 10 / 90, or may be 0.15 / 99.85 to 5 / 95, or may be 0.5 / 99.5 to 2 / 98.

[0032] In the polyamino acid derivative represented by the above general formula (2) according to this embodiment, the monomer units AU, BU, and CU are structural units derived from hydrophobic amine A, hydrophilic amine B, and succinimide, respectively (described in detail in the synthesis method described later). The number of moles of each structural unit can be adjusted by the amount of each raw material used in the synthesis. For example, in the synthesis method described later, it can be prepared by using the blending ratio of polysuccinimide (PSI) and monoamine, the blending ratio of various monoamines, etc. The actual composition of each monomer unit AU, BU, and CU in the obtained nonionic polyamino acid derivative is 1 It can be calculated from HNMR.

[0033] In the general formula (2), it is preferable that n, m, and o, o / (n+m), are within a range of 0.15 / 99.85 to 10 / 90.

[0034] [ka] In the above general formula (3), R1, R 2、 n, m, and l have the same meaning as in the above general formula (2), provided that l>0.

[0035] [Polysuccinimide (PSI)] The polysuccinimide (PSI) according to this embodiment is a polymer represented by the following formula (4).

[0036] [ka] (In the formula, n=10~10000)

[0037] There is no particular limitation on the method for producing polysuccinimide (PSI), but for example, aspartic acid is heated in a vacuum at 170 to 190°C in the presence of phosphoric acid, and dehydration condensation is performed. In order to obtain a polysuccinimide (PSI) having a higher molecular weight, the polysuccinimide (PSI) obtained as described above may be treated with a condensing agent such as dicyclohexylcarbodiimide. There is no particular limitation on the molecular weight of polysuccinimide (PSI). For example, the weight average molecular weight is preferably 20,000 or more, more preferably 50,000 or more, and even more preferably 70,000 or more. The molecular weight of polysuccinimide (PSI) is preferably 500,000 or less, and more preferably 200,000 or less. The weight average molecular weight in this case is a conversion value obtained by the GPC method using polystyrene as a standard substance.

[0038] [Monoamines] The monoamine according to the present embodiment is preferably a monoamine represented by the following general formula (5) or (6). R3-NH2(5) (In the formula, R3 has the same meaning as R1 in the above general formula (1). R3 preferably represents a hydrocarbon group having 3 to 18 carbon atoms.) R4-NH2(6) (In the formula, R4 has the same meaning as R2 in the above general formula (1). R4 is preferably a hydroxyalkyl group having 2 to 5 carbon atoms.)

[0039] In the monoamine represented by the above general formula (5), R3 preferably represents a hydrocarbon group having 3 to 18 carbon atoms, more preferably represents a hydrocarbon group having 6 to 14 carbon atoms, and further preferably represents a hydrocarbon group having 10 to 12 carbon atoms. The hydrocarbon group in R3 is preferably an alkyl group. The alkyl group is preferably a straight chain group containing no branched structure. Examples of R4 in the monoamine represented by the above general formula (5) include linear alkyl groups such as propyl, butyl, pentyl, hexyl, octyl, dodecyl, and octadecyl; branched alkyl groups such as isopropyl, isobutyl, isopentyl, and isohexyl; cycloalkyl groups such as cyclobutyl, cyclopentyl, and cyclohexyl; cycloalkylalkyl groups such as cyclobutylmethyl, cyclopentylmethyl, cyclohexylmethyl, cyclobutylethyl, cyclopentylethyl, cyclohexylethyl, cyclobutylpropyl, cyclopentylpropyl, cyclohexylpropyl, cyclobutylbutyl, cyclopentylbutyl, and cyclohexylbutyl; and alkenyl groups such as propenyl, butenyl, pentenyl, and hexenyl. An example of the monoamine represented by the above general formula (5) is n-dodecylamine.

[0040] In the monoamine represented by the above general formula (6), R4 preferably represents a group selected from the group consisting of a hydroxyalkyl group having 2 to 5 carbon atoms, a methoxyalkylmethyl group having 3 to 6 carbon atoms, and an ethoxyalkylmethyl group having 4 to 7 carbon atoms, and more preferably represents a group selected from the group consisting of a hydroxyalkyl group having 2 to 4 carbon atoms, a methoxyalkylmethyl group having 4 to 6 carbon atoms, and an ethoxyalkylmethyl group having 4 to 5 carbon atoms.

[0041] Examples of R3 in the monoamine represented by the above general formula (5) include hydroxyalkyl groups such as a hydroxyethyl group, a hydroxypropyl group, a hydroxybutyl group, and a hydroxypentyl group; hydroxyalkoxy groups such as a hydroxyethoxyethyl group; methoxyalkyl groups such as a methoxymethyl group, a methoxyethyl group, a methoxypropyl group, a methoxybutyl group, a methoxypentyl group, and an ethoxymethyl group; and ethoxyalkyl groups such as an ethoxyethyl group, an ethoxypropyl group, an ethoxybutyl group, and an ethoxypentyl group. Examples of the monoamine represented by the above general formula (6) include hydroxypropylamine, isopropanolamine, and ethanolamine.

[0042] [Method for producing polyamino acid derivatives] The method for producing a polyamino acid derivative according to the present embodiment includes a ring-opening reaction method of polysuccinimide (PSI) by reaction with a monoamine. By reacting polysuccinimide (PSI) with the monoamine, the imide ring of polysuccinimide (PSI) is opened. When the total amount of the monoamine used is less than 1 equivalent to the equivalent of the monomer unit of polysuccinimide (PSI), unreacted imide rings generally remain. In the method for producing a polyamino acid derivative according to the present embodiment, it is preferable that the monoamine contains a monoamine represented by the above general formula (3) (sometimes referred to as hydrophobic amine A) and a monoamine represented by the general formula (4) (sometimes referred to as hydrophilic amine B), and the molar ratio of the hydrophobic amine A to the hydrophilic amine B is 45 / 55 to 60 / 40. It is more preferable that the monoamine contains a hydrophobic amine A and a hydrophilic amine B, and the molar ratio of the hydrophobic amine A to the hydrophilic amine B is 50 / 55 to 55 / 45.

[0043] In the method for producing a polyamino acid derivative according to the present embodiment, the monoamine may contain a hydrophobic amine A and a hydrophilic amine B, and may also contain a monoamine other than the hydrophobic amine A and the hydrophilic amine B. In this case, the total molar amount of the hydrophobic amine A and the hydrophilic amine B in the monoamine is preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more. The monoamine may also be the hydrophobic amine A and the hydrophilic amine B.

[0044] The unreacted imide ring may remain as it is, or may be further subjected to a ring-opening reaction using another monoamine, or, if desired, the unreacted imide ring may be opened with a substituted amine such as ethanolamine, cysteamine, or dibutylamine.

[0045] "Organic solvent" In the method for producing a polyamino acid derivative according to this embodiment, the organic solvent is not particularly limited as long as it can substantially dissolve polysuccinimide (PSI) and monoamine and / or does not substantially inhibit the progress of the reaction.

[0046] Specific examples of the organic solvent include aprotic polar organic solvents such as dimethylformamide (DMF), dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethylimidazolidinone (DMI), dimethylsulfoxide (DMSO), and sulfolane, which may be used alone or in combination.

[0047] "Monoamine usage" The total amount of the monoamine used according to the present embodiment is not particularly limited as long as it is substantially soluble in the organic solvent and / or does not substantially inhibit the progress of the reaction. The amount of the monoamine used is generally 0.1 to 10 times equivalent, preferably 0.1 to 1.0 times equivalent, relative to the equivalent of the monomer unit of polysuccinimide (PSI).

[0048] "Basic catalyst" In the method for producing polyamino acid derivatives according to the present embodiment, the basic catalyst that is optionally used is not particularly limited as long as it substantially accelerates the reaction rate.Specific examples of the basic catalyst include aliphatic tertiary amines such as trimethylamine, triethylamine, tripropylamine, tributylamine, diisopropylethylamine (DIEA), triethanolamine, triethylenediamine (DABCO), etc., alicyclic tertiary amines such as N-methylmorpholine, aromatic tertiary amines such as dimethylaniline, diethylaniline, etc., and tetramethylguanidine, etc., which can be used alone or in combination.

[0049] "Amount of basic catalyst used" In the method for producing a polyamino acid derivative according to the present embodiment, the amount of the basic catalyst used is not particularly limited as long as it substantially accelerates the reaction rate. The amount of the basic catalyst used is generally 0 to 2 equivalents relative to the equivalent of the monoamine. When the amino acid ester is a mineral acid salt, a neutralization equivalent of a base is further added.

[0050] "Reaction temperature" In the method for producing a polyamino acid derivative according to the present embodiment, the reaction temperature is not particularly limited as long as the reaction progress can be substantially maintained. The reaction temperature is generally selected from a temperature range of 5 to 150°C, and room temperature is usually selected. The reaction temperature can also be selected from a temperature range of 5 to 150°C to be optimal for the monoamine used.

[0051] "Concentration of reaction system" The concentration of the reaction system employed in the method for producing a polyamino acid derivative according to the present embodiment is not particularly limited as long as the reaction progress can be substantially maintained. The concentration of the reaction system is selected based on the concentration of polysuccinimide (PSI), and generally, the polysuccinimide (PSI) concentration is selected from a concentration range of 1 to 50% by weight. The concentration of the reaction system can also be selected from a polysuccinimide (PSI) concentration range of 1 to 50% by weight, so that the optimum concentration for the monoamine used is selected.

[0052] <Method for isolating polyamino acid derivatives> The method for isolating the polymer produced from the reaction solution after the reaction in the method for producing a polyamino acid derivative according to the present embodiment is not particularly limited as long as it can isolate the reaction product with a desired purity. The isolation method may be any known or publicly used method. Generally, known or publicly used isolation procedures such as concentration, recrystallization, or reprecipitation are used.

[0053] A specific example of the isolation method is, for example, a method in which an excess of a poor solvent (e.g., ethyl acetate, methyl alcohol, ethyl alcohol, isopropyl alcohol, etc.) is added to the reaction solution in which the reaction product is dissolved at an appropriate temperature after the completion of the reaction, the precipitated crystals of the reaction product are isolated by decantation, filtration, suction filtration, etc., and the crystals are thoroughly washed with a poor solvent that does not dissolve the crystals, followed by drying, etc. Another specific example is, for example, a method in which, after the completion of the reaction, the reaction solution in which the reaction product is dissolved is added to the same excess of a poor solvent as above at an appropriate temperature, and the precipitated crystals of the reaction product are isolated, washed, and dried in the same manner as above, etc.

[0054] In the method for producing polyamino acid derivatives according to the present embodiment, the obtained polyamino acid derivatives may not be isolated, and the mixture after the reaction may be used as it is. Also, if necessary, only a part of unreacted raw materials other than the solvent may be removed, and the mixture may be added to the composition described below. Also, the concentration may be adjusted by increasing or decreasing the amount of the solvent in the mixture.

[0055] <Mechanism of thickening of polyamino acid derivatives> The thickening effect of the polyamino acid derivative of this embodiment can be explained by the thickening mechanism shown in FIG. In polyamino acid derivatives, hydrophobic alkyl groups exist in the side chains on the polyaspartic acid chain. The thickening effect is caused by molecular association between the hydrophobic groups in the side chains. For example, when an aqueous solution of polyamino acid derivatives is stirred, the shear is strengthened, the molecular association is broken, and the viscosity becomes low, and when it is left to stand, the shear is weakened, the molecular association is formed, and the viscosity becomes high.

[0056] <Slightly cross-linked polyamino acid derivatives> The polyamino acid derivative represented by the above general formula (1) according to this embodiment may be a slightly crosslinked polyamino acid derivative represented by the above general formula (2). The "slightly crosslinked polyamino acid derivative represented by general formula (2)" is a compound in which the molar number o of Crosslink-U in general formula (2) is not 0. The "slightly crosslinked polyamino acid derivative represented by general formula (2)" may also be simply referred to as a "slightly crosslinked polyamino acid derivative". The slightly crosslinked polyamino acid derivative according to this embodiment is obtained by further crosslinking a monoamine-modified polyamino acid derivative obtained by ring-opening polysuccinimide (PSI) using a monoamine with a trace amount of a crosslinking agent. The slightly crosslinked polyamino acid derivative represented by the above general formula (2) according to this embodiment has a small amount of crosslinking portion Crosslink-U, and the crosslinking amount of the slightly crosslinked polyamino acid derivative is preferably 0.1 to 2.0 mol%, more preferably 0.3 to 1.8 mol%, and even more preferably 0.5 to 1.7 mol%. For example, in the examples described later, the crosslinking amount of the slightly crosslinked polyamino acid derivative was 1.5 mol%. In the slightly crosslinked polyamino acid derivative of this embodiment, the crosslinking portion Crosslink-U contains a structure derived from a crosslinking agent (described in detail in the synthesis method described later). The number of moles of the crosslinking portion Crosslink-U can be adjusted by the amount of the crosslinking agent and other raw materials used in the synthesis.

[0057] In addition, the "slightly cross-linked polyamino acid derivative" of the present invention means a modified polyamino acid derivative with a cross-linking amount of 0.1 to 2.0 mol%. "Slightly cross-linked" is distinguished from normal "cross-linked" with a cross-linking amount of more than 2.0 mol%. For example, since the cross-linking amount of a slightly cross-linked polymer is small, a solution of a given concentration does not gel and can maintain a certain fluidity. The method for calculating the cross-linking amount of a slightly cross-linked polyamino acid derivative will be described in the Examples.

[0058] In the slightly crosslinked polyamino acid derivative represented by the above general formula (2) according to this embodiment, the monomer units AU and BU have the same meanings as in the polyamino acid derivative represented by the above general formula (1).

[0059] [Crosslinking Agent] The crosslinking agent according to the present embodiment is not particularly limited as long as it can form the bond. A specific example of a crosslinking agent that is preferable for forming an amide bond used in the crosslinking portion is a polyfunctional amine.

[0060] The polyfunctional amine according to this embodiment is preferably an amine having at least two primary and / or secondary amino groups. Examples of the diamine compound include aliphatic diamines such as ethylenediamine and hexamethylenediamine, and aliphatic diamines containing aromatic rings such as xylenediamine; alicyclic diamines such as norbornenediamine; ether-based diamines such as 1,2-bis(2-aminoethoxy)ethane (AEE), diethylene glycol bis(3-aminopropyl)ether (bis[2-(3-aminopropoxy)ethyl ether (APEE)), polyoxyethylenediamine, and polyoxypropylenediamine; amino acids and derivatives thereof having amino groups in the side chains such as lysine and ornithine; and monoamino compounds linked by disulfide bonds such as cystine and cystamine, and derivatives thereof. The polyfunctional amine according to the present embodiment is preferably free of the above amino acids and derivatives thereof. The polyfunctional amine according to the present embodiment is preferably an ether-based diamine from the viewpoint of being less likely to generate bumps during the crosslinking reaction due to its flexible structure and being easy to control the crosslinking reaction.

[0061] Examples of polyfunctional amine compounds other than diamines include tris(2-aminoalkyl)amines (wherein the alkyl carbon atom number is preferably 1 to 5, and more preferably 2 to 4), such as tris(2-aminoethyl)amine (TREN) and tris(3-aminopropyl)amine; diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

[0062] Preferred examples of the polyfunctional amine according to this embodiment include 1,2-bis(2-aminoethoxy)ethane (AEE), bis[2-(3-aminopropoxy)ethyl ether (APEE), and tris(2-aminoethyl)amine (TREN).

[0063] The reaction between polysuccinimide and polyfunctional amine can be carried out in an organic solvent, for example. The reaction will be described below using an example in which the polyfunctional amine according to the present embodiment is a diamine. In the method of reacting polysuccinimide with diamine in an organic solvent, polysuccinimide is dissolved in an aprotic polar organic solvent such as dimethylformamide (DMF), dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethylimidazolidinone (DMI), dimethylsulfoxide (DMSO), sulfolane, etc., and then diamine or a solution of diamine in the organic solvent is dropped. At this time, the amount of the organic solvent used to dissolve polysuccinimide is not particularly limited, but it is usually used at a polymer concentration of 1 to 50 mass%.

[0064] The temperature at which the polysuccinimide and the diamine are reacted is not particularly limited, but is, for example, room temperature to 80°C.

[0065] The reaction conditions (such as reaction temperature, reaction time, reaction concentration, and amount of diamine used) are not particularly limited, but it is preferable to set the reaction conditions such that the entire reaction solution does not gel.

[0066] [Method for producing slightly crosslinked polyamino acid derivatives] As a method for producing the slightly crosslinked polyamino acid derivative according to the present embodiment, for example, a method of ring-opening reaction of polysuccinimide (PSI) using polysuccinimide (PSI), a crosslinking agent such as a trace amount of a polyfunctional amine compound, and a monoamine is mentioned. The order of addition of the crosslinking agent and the monoamine is not particularly limited. The monoamine may be added first and then the crosslinking agent, or the monoamine and the crosslinking agent may be added simultaneously, or the crosslinking agent may be added first and then the monoamine. From the viewpoint of easy control of the amount of crosslinking, it is preferable to add the crosslinking agent first and then add the monoamine after the crosslinking reaction has progressed.

[0067] For example, when a polyfunctional amine compound is used as a crosslinking agent, polysuccinimide (PSI) is reacted with a crosslinking agent such as a trace amount of a polyfunctional amine compound, and then a monoamine is added to perform a ring-opening reaction of polysuccinimide (PSI) by reacting with the monoamine. After reacting polysuccinimide (PSI) with a crosslinking agent such as a trace amount of a polyfunctional amine compound, polysuccinimide (PSI) is reacted with the monoamine, and the imide ring of polysuccinimide (PSI) is opened. In addition, since a trace amount of a crosslinking agent such as a polyfunctional amine compound is used, the obtained polyamino acid derivative has a crosslinked structure of a trace amount. The total amount of the crosslinking agent and the monoamine used may be less than 1 equivalent to the equivalent of the monomer unit of polysuccinimide (PSI) to perform the ring-opening reaction, and unreacted imide rings may remain, or may be more than 1 equivalent to perform the ring-opening reaction, and no unreacted imide rings may remain.

[0068] In the method for producing a slightly crosslinked polyamino acid derivative according to the present embodiment, the monoamine preferably contains a monoamine represented by the above general formula (6) (sometimes referred to as hydrophobic amine A) and a monoamine represented by the general formula (7) (sometimes referred to as hydrophilic amine B), and the molar ratio of the hydrophobic amine A to the hydrophilic amine B is 45 / 55 to 60 / 40. It is more preferable that the monoamine contains a hydrophobic amine A and a hydrophilic amine B, and the molar ratio of the hydrophobic amine A to the hydrophilic amine B is 50 / 55 to 55 / 45.

[0069] In the method for producing a slightly crosslinked polyamino acid derivative according to the present embodiment, the monoamine may contain a hydrophobic amine A and a hydrophilic amine B, or may contain a monoamine other than the hydrophobic amine A and the hydrophilic amine B. In this case, the total molar amount of the hydrophobic amine A and the hydrophilic amine B in the monoamine is preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more. The monoamine may be the hydrophobic amine A and the hydrophilic amine B.

[0070] The unreacted imide ring may remain as it is, or may be further subjected to a ring-opening reaction using another monoamine, or, if desired, the unreacted imide ring may be opened with a substituted amine such as ethanolamine, cysteamine, or dibutylamine.

[0071] "Amount of crosslinking agent used" The amount of the crosslinking agent used in this embodiment is not particularly limited, as long as it is sufficient to obtain a slightly crosslinked polyamino acid derivative with a small amount of crosslinking structure introduced to such an extent that gelation does not occur. For example, in the finally synthesized slightly crosslinked polyamino acid derivative represented by the above general formula (4), the amount of crosslinking may be 0.1 to 2.0 mol%. It is preferably 0.3 to 1.8 mol%, more preferably 0.4 to 1.7 mol%, and even more preferably 0.5 to 1.5 mol%. For example, when a polyfunctional amine is used as a crosslinking agent, the amount of the polyfunctional amine used is 0.1 to 2.0 mol, preferably 0.2 to 1.5 mol, more preferably 0.3 to 1.3 mol, and even more preferably 0.4 to 1.0 mol, relative to 100 moles of polysuccinimide in terms of moles. When the amount of the polyfunctional amine used is 2 moles relative to 100 moles of polysuccinimide in terms of moles, it is simply stated that "the amount of the polyfunctional amine used is 2 moles". When the amount of polyfunctional amine used is in the range of 0.1 to 2.0 mol%, the thickening composition of this embodiment can achieve a high thickening effect while maintaining a certain level of viscosity for a longer period of time. Here, the converted molar number of polysuccinimide means the molar number of aspartic acid, which is the raw material used, in the above-mentioned method for synthesizing polysuccinimide.

[0072] "Monoamine usage" The total amount of the monoamine used in this embodiment is the same as that in the production method of the polyamino acid derivative represented by the general formula (1).

[0073] "Basic catalyst" In the method for producing the slightly crosslinked polyamino acid derivative according to the present embodiment, a catalyst may not be used, or a basic catalyst may be used. The basic catalyst that is used optionally is not particularly limited as long as it substantially accelerates the reaction rate. Specific examples of the basic catalyst are the same as those in the method for producing the polyamino acid derivative represented by the general formula (1).

[0074] "Amount of basic catalyst used" In the method for producing a slightly crosslinked polyamino acid derivative according to this embodiment, the amount of the basic catalyst used is the same as in the method for producing the polyamino acid derivative represented by the general formula (1) above.

[0075] "Reaction temperature" In the method for producing a slightly crosslinked polyamino acid derivative according to the present embodiment, the reaction temperature is not particularly limited as long as the reaction progress can be substantially maintained. The reaction temperature is generally selected from a temperature range of 5 to 150°C. The reaction temperature can also be selected as an optimum temperature from the viewpoints of the monoamine used, shortening the reaction time, improving the reaction rate, etc. The method for producing a slightly crosslinked polyamino acid derivative according to the present embodiment preferably includes a crosslinking reaction step in which a crosslinking agent is added first and a monoamine reaction step in which a monoamine is added thereafter. In this case, the temperature of the crosslinking reaction and the temperature of the monoamine reaction may be the same or different. It is preferable that the temperature of the crosslinking reaction is lower than the reaction temperature after the addition of the monoamine. In the crosslinking reaction step in which a crosslinking agent is added to polysuccinimide (PSI) and a crosslinking reaction proceeds, the reaction temperature may be 120°C or lower, or 100°C or lower. It may also be 20°C or higher. For example, when the crosslinking agent is an ether-based diamine or tris(2-aminoalkyl)amine, the reaction temperature in the crosslinking reaction step is preferably 100°C or lower, more preferably 80°C or lower, further preferably 60°C or lower, and may be 50°C or lower. It may also be 20°C or higher. In the crosslinking reaction step, if the reaction temperature is within the above range, crosslinking can proceed uniformly. As a result, the thickening composition containing the slightly crosslinked polyamino acid derivative obtained by the above production method can achieve both thickening power and storage stability.

[0076] "Concentration of reaction system" The concentration of the reaction system employed in the method for producing a slightly crosslinked polyamino acid derivative according to this embodiment is the same as that in the method for producing a polyamino acid derivative represented by the general formula (1) above.

[0077] <Method for isolating slightly cross-linked polyamino acid derivatives> In the method for producing a slightly crosslinked polyamino acid derivative according to this embodiment, the method for isolating the produced polymer from the reaction solution after completion of the reaction is the same as in the method for producing the polyamino acid derivative represented by the general formula (1) above.

[0078] <Ingredient (b)> The component (b) according to this embodiment is a compound having a hydrophobic group. The component (b) according to this embodiment may be a thickening compound having a hydrophobic group. The thickening compound is not limited to those represented by the above general formula (1). The component (b) according to this embodiment may be a compound derived from a natural substance or a compound having biodegradability.

[0079] Examples of the thickening compound having a hydrophobic group include hydrophobically modified cellulose derivatives, hydrophobically modified polysaccharides, hydrophobically modified polyurethanes, and hydrophobically modified polyacrylic acids. Examples of the naturally occurring compounds include hydrophobically modified cellulose derivatives and hydrophobized polysaccharides. Examples of the biodegradable compound include hydrophobically modified cellulose derivatives and hydrophobized polysaccharides.

[0080] Examples of the hydrophobically modified cellulose derivatives include Natrosol Plus 330CS and Polysurf 67CS manufactured by Ashland Corporation, and Sangelo 60L manufactured by Daido Chemical Industry Co., Ltd.

[0081] The hydrophobic group is preferably a hydrocarbon group having 4 to 32 carbon atoms, more preferably a hydrocarbon group having 6 to 22 carbon atoms, and even more preferably a hydrocarbon group having 10 to 22 carbon atoms.

[0082] The content of component (b) in the thickening composition of the present embodiment is not limited to a specific value. The content of component (b) may be, for example, 1% by mass to 90% by mass, 3% by mass to 80% by mass, preferably 5% by mass to 70% by mass, more preferably 10% by mass to 60% by mass, and even more preferably 30% by mass to 60% by mass, relative to 100% by mass of the total of components (a) and (b) in the cosmetic composition of the present embodiment.

[0083] <Water> The thickening composition of the present embodiment may not contain water. For example, the cosmetic composition of the present embodiment obtained by the method described below may be further subjected to a drying treatment or the like to obtain a powdery cosmetic composition.

[0084] The thickening composition of the present embodiment may contain water. For example, the thickening composition of the present embodiment obtained by the above-mentioned method may be used as it is. Examples of the water of the present embodiment include ion-exchanged water. Furthermore, when the cosmetic composition contains water, the "thickening composition containing water" is sometimes referred to as a "thickening solution." The water content may be 40% by mass to 99.99% by mass, 60% by mass to 99.95% by mass, or 80% by mass to 99.9% by mass, relative to 100% by mass of the total thickening composition including water.

[0085] When the cosmetic composition contains water, the pH value thereof is preferably in the range of 4.5-8.0, and more preferably in the range of 5-7. The method for adjusting the pH value is not particularly limited, and may be a method using an acidic or basic substance. Specific examples of acids include organic acids such as citric acid. Specific examples of bases include organic basic compounds such as ammonia and inorganic basic compounds such as sodium hydroxide.

[0086] <Other ingredients> The thickening composition of the present embodiment may further contain other ingredients, such as cosmetic active ingredients, and additives commonly used in cosmetics, such as surfactants, stabilizers, and moisturizers.

[0087] <Method of preparing thickening composition> An example of a method for preparing the thickening composition of the present embodiment is to weigh out a predetermined amount of the polyamino acid derivative according to the present embodiment described above as component (a), and a predetermined amount of the compound having a hydrophobic group according to the present embodiment described above as component (b), and, if necessary, add a predetermined amount of water or other components, and stir to prepare the thickening composition. When the cosmetic composition of the present embodiment contains water, an aqueous dispersion of the polyamino acid derivative of the present embodiment may be prepared first, and then mixed with other components, if necessary. When the cosmetic composition of the present embodiment does not contain water, a predetermined amount of solid polyamino acid derivative is weighed as component (a), a predetermined amount of solid compound having a hydrophobic group is weighed as component (b), and if necessary, other solid components may be mixed. Alternatively, a dispersion containing the polyamino acid derivative, the compound having a hydrophobic group, and water may be prepared first, and if necessary, the mixture may be mixed with other components to prepare a mixed liquid, which may then be dried before preparation. The preparation temperature is not particularly limited, but heating to 60 to 80° C. will speed up dispersion and dissolution in water.

[0088] (Cosmetic composition) The cosmetic composition according to this embodiment contains the thickening composition and a cosmetic active ingredient. Examples of the cosmetic active ingredient include higher alcohols, lower alcohols, polyhydric alcohols, pH adjusters, surfactants, sequestering agents, antioxidants, physical and chemical sunscreens, vitamins, skin protectants, oils and fats, hydrocarbon oils, moisturizers, antiperspirants, detergents, fragrances, cosmetic colorants, antibacterial agents, germicides, texture improvers and foam stabilizers, other thickeners, etc. The cosmetic composition according to this embodiment may further contain water. When the cosmetic composition according to this embodiment contains water, the content of the polyamino acid derivative according to this embodiment is preferably 0.05 to 10 mass%, more preferably 0.1 to 7.0 mass%, even more preferably 0.3 to 5.0 mass%, and particularly preferably 0.5 to 3.0 mass%, relative to 100 mass% of the total cosmetic composition. EXAMPLES

[0089] The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto.

[0090] (raw materials) Aspartic acid: YIXING QIANCHENG BIO-ENGINEERING Co., Ltd., 99.97% purity Phosphoric acid: Kanto Chemical Co., 85% purity Dimethylformamide (DMF): Kanto Chemical Co., Ltd., 99.5% purity n-Dodecylamine: Kao Corporation, Farmin 20D Propanolamine (3-amino-1-propanol): Kanto Chemical Co., Ltd., 99% purity 1,2-Bis(2-aminoethoxy)ethane (AEE): Aldrich, 98% purity Ethyl acetate: Godo Co., Ltd., 99% purity Sangelose 60L: Stearoxy hydroxypropyl methylcellulose manufactured by Daido Kasei Kogyo Co., Ltd. Hydroxypropyl methylcellulose (HPMC): Sigma-Aldrich

[0091] (Evaluation method) <Viscosity evaluation> The shear viscosity of the composition was measured using a rotational rheometer (R / Splus manufactured by Brookfield), and the viscosity was evaluated at a shear rate of 5 (1 / sec).

[0092] <Tactile evaluation> The compositions were applied to the skin, and the refreshing feeling felt at that time was evaluated by a panel of 10 experts according to the following criteria. <Evaluation criteria> A: There were 8 to 10 panelists who answered simply. B: Five to seven panelists gave straightforward answers. C: 0-4 panelists gave straightforward answers.

[0093] (Synthesis Example 1) <Synthesis of polysuccinimide (PSI)> 160 parts of aspartic acid and 83 parts of 85% phosphoric acid were mixed in a mortar, transferred to a tray, and reacted at 190°C and 1.3 kPa for 6 hours. The reaction mixture was pulverized, washed with distilled water until the filtrate became neutral, and vacuum dried at 80°C to obtain 115 parts of polysuccinimide (PSI) having a weight average molecular weight of 80,000.

[0094] <Measurement of weight average molecular weight of polysuccinimide (PSI)> The weight average molecular weight of polysuccinimide (PSI) was determined as a polystyrene equivalent value by the GPC method (differential refractometer). For the measurement, a G1000HHR column, a G4000HHR column, and a GMHHR-H column (TSKgel (registered trademark), Tosoh Corporation) were used. Dimethylformamide containing 10 mM lithium bromide was used as the eluent.

[0095] (Synthesis Example 2) <Synthesis of polyamino acid derivative 1> 10.0g of PSI and 95.3g of DMF were placed in a reaction vessel and completely dissolved under heating at 60°C. After lowering the temperature to 40°C, a mixture of 0.229g of 1,2-bis(2-aminoethoxy)ethane (1.5 mol% relative to polysuccinimide) and 2.06g of DMF was added and reacted for 7 hours. Next, 10.3g of Farmin 20D (n-dodecylamine) (54 mol% relative to polysuccinimide) was added and reacted for 30 minutes. Furthermore, 3.45g of propanolamine (44.5 mol% relative to polysuccinimide) was added and reacted for 7 hours while maintaining the temperature in the reaction vessel at 60°C, and then the reaction vessel was cooled and left to stand overnight at room temperature. Thereafter, the reaction solution was discharged into 1200mL of ethyl acetate while stirring to precipitate the reactant, and the solid was collected by filtration. The reaction was further washed in 600mL of ethyl acetate while stirring, and the solid was collected by filtration. The recovered solid was dried at 60° C. under reduced pressure for 12 hours to obtain 22.0 g of a modified polyaspartic acid derivative.

[0096] (Synthesis Example 3) <Synthesis of polyamino acid derivative 2> 10.0g of PSI and 54.7g of DMF were placed in a reaction vessel and completely dissolved under heating at 60°C. After lowering the temperature to 40°C, 9.55g of Farmin 20D (n-dodecylamine) (50 mol% relative to polysuccinimide) was added and reacted for 30 minutes. Furthermore, 3.87g of propanolamine (50 mol% relative to polysuccinimide) was added and reacted for 7 hours while maintaining the temperature in the reaction vessel at 60°C. The reaction vessel was then cooled and allowed to stand overnight at room temperature. Thereafter, the reaction solution was discharged into 1200mL of ethyl acetate while stirring to precipitate the reactant, and the solid was collected by filtration. The reaction was further washed in 600mL of ethyl acetate while stirring, and the solid was collected by filtration. The collected solid was dried under reduced pressure at 60°C for 12 hours to obtain 20.0g of modified polyaspartic acid derivative.

[0097] (Examples 1 to 8) <Adjustment of thickening solution> In Examples 1 to 8, the polyamino acid derivatives obtained in Synthesis Examples 2 and 3 for viscosity evaluation and Sangelose 60L as hydrophobically modified cellulose were mixed with ion-exchanged water to the concentrations shown in Table 1, and then stirred at 70° C. for 1 hour. The mixture was then cooled to room temperature to obtain the thickening compositions of Examples 1 to 8. The shear viscosity and texture of each thickening composition were evaluated using the above-mentioned evaluation methods. The results are shown in Table 1.

[0098] (Comparative Examples 1 to 7) <Adjustment of thickening solution> In Comparative Examples 1 to 7, for viscosity evaluation, the polyamino acid derivatives obtained in Synthesis Examples 2 and 3, respectively, and hydroxypropylmethylcellulose (HPMC) were mixed with ion-exchanged water to the concentrations shown in Table 1, and then stirred at 70° C. for 1 hour. The mixture was then cooled to room temperature to obtain thickening compositions of Comparative Examples 1 to 7. The shear viscosity and texture of each thickening composition were evaluated using the above-mentioned evaluation methods. The results are shown in Table 1.

[0099] [Table 1]

[0100] (Consideration) From the results of Examples 1 to 8 and Comparative Examples 1 to 7, the effects of the present invention were confirmed. That is, in Examples 1 to 8, when Sangelose 60L was contained in an amount of 0.1 to 0.6% by mass, a refreshing feel was observed when applied to the skin, and a viscosity of 4200 mPa s or more was obtained. Both a refreshing feel and a thickening effect were achieved at the same time. On the other hand, in Comparative Examples 1, 2, 6, and 7, when only the polyaspartic acid derivative was used, a refreshing feel was obtained, but the thickening effect was insufficient. In Comparative Example 3, when HPMC was used instead of Saint-Jello 60L, a refreshing feel was obtained, but the thickening effect was insufficient. In Comparative Examples 4 and 5, when only Saint-Jello 60L was used, a refreshing feel was not obtained. In particular, comparing Example 2 using Sangelose 60L with Comparative Example 2 using HPMC, even at the same blending amount of 0.2 mass%, Example 2 using Sangelose 60L having a hydrophobic group achieved a thickening effect four times or more. It is believed that the hydrophobic groups in the polyaspartic acid derivative and the hydrophobic groups in Sangelose 60L interact with each other to form larger associations than those formed by the polyaspartic acid derivative alone, resulting in a significant improvement in viscosity.

Claims

1. A thickening composition comprising component (a) and component (b), The component (a) is a polyamino acid derivative containing a repeating unit represented by the following general formula (1): A thickening composition, wherein the component (b) is a compound having a hydrophobic group. 【Chemistry 1】 (In the formula, R １ contains at least a hydrocarbon group having 3 to 22 carbon atoms, R ２ contains at least a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. n and m respectively represent the number of moles of α-type or β-type polyaspartic acid monomer units A-U and B-U in the molecule. In the polyamino acid derivative, the bonding form of the monomer units A-U and B-U may be any of a random form, a block form, and a tapered form.

2. 2. The thickening composition according to claim 1, wherein the component (a) is a polyamino acid derivative containing a repeating unit represented by the following general formula (2): 【Chemistry 2】 (In the formula, R １ contains at least a hydrocarbon group having 3 to 22 carbon atoms, R ２ contains at least a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. n and m respectively represent the number of moles of α-type or β-type polyaspartic acid monomer units A-U and B-U in the molecule, and l represents the number of moles of succinimide monomer units C-U. l / (n+m) is 0 / 100 to 20 / 80. Crosslink-U represents a crosslinked portion. The wavy line of the crosslinked portion represents the crosslinked position. o represents the number of moles of Crosslink-U. o / (n+m) is 0 / 100 to 10 / 90. In the polyamino acid derivative, the bonding form of the monomer units A-U, B-U, C-U, and Crosslink-U may be any of a random form, a block form, and a tapered form.

3. R in the general formula (2) １ represents a hydrocarbon group having 3 to 22 carbon atoms, and R in the general formula (2) ２ The thickening composition according to claim 2, wherein represents a hydrocarbon group having 1 to 20 carbon atoms which may contain heteroatoms.

4. 4. The thickening composition according to claim 1, wherein the hydrophobic group in component (b) is a hydrocarbon group having 4 to 32 carbon atoms.

5. The thickening composition according to any one of claims 1 to 3, wherein the component (b) is a hydrophobically modified cellulose derivative.

6. R in the general formula (1) ２ The thickening composition according to claim 1 or 2, wherein R represents a hydroxyalkyl group having 2 to 6 carbon atoms.

7. The thickening composition according to any one of claims 1 to 3, wherein in the general formula (1), the molar ratio, n / m, of the monomer units AU and BU is 40 / 60 to 60 / 40.

8. The thickening composition according to any one of claims 1 to 3, wherein the crosslinking amount of the polyamino acid derivative is 0.1 to 2.0 mol %.

9. The thickening composition according to any one of claims 1 to 3, further comprising water.

10. A thickening composition according to any one of claims 1 to 3, A cosmetic active ingredient, A cosmetic composition comprising:

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