Oil-in-water emulsion composition

Abstract

This oil-in-water emulsion composition comprises: a polyaspartic acid derivative that contains, in a prescribed ratio, a monomer unit A-U represented by general formula (1) (where R1 indicates a hydrocarbon group having 3-22 carbon atoms) and a monomer unit B-U represented by general formula (2) (where R2 indicates a hydrocarbon group having 1-20 carbon atoms and including a heteroatom); and an oily component.

Description

Oil-in-water emulsion composition

[0001] The present disclosure relates to an oil-in-water emulsion composition containing a polyaspartic acid derivative.

[0002] Polyacrylic acid polymers, such as carboxyvinyl polymer, are widely known as thickeners and have been used in a variety of applications, including toiletries and cosmetics. Although a small amount of carboxyvinyl polymer can produce a moist gel, there is a growing demand for thickeners that can replace carboxyvinyl polymers from an environmentally friendly perspective.

[0003] Polysaccharides such as xanthan gum are known as thickeners that can replace carboxyvinyl polymers (see Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2021-095340

[0005] However, polysaccharides such as xanthan gum sometimes do not have a sufficient thickening effect. Therefore, an object of the present disclosure is to provide an oil-in-water emulsion composition that contains a thickener with low environmental impact and has sufficient viscosity.

[0006] As a result of intensive research to solve the above-mentioned problems, the inventors of the present disclosure discovered that the above-mentioned problems can be solved by using a polyaspartic acid derivative having a specific structure as a thickener, and thus completed the invention of the present disclosure.

[0007] That is, the gist of the present disclosure is as follows: [1] An oil-in-water emulsion composition comprising a polyaspartic acid derivative and an oily component, wherein the polyaspartic acid derivative comprises α- or β-aspartic acid monomer units A-U represented by the following general formula (1) and α- or β-aspartic acid monomer units B-U represented by the following general formula (2), and the ratio (A-U) / (B-U) of the content (mol %) of the monomer units A-U to the content (mol %) of the monomer units B-U in the polyaspartic acid derivative is 40 / 60 to 60 / 40. (In the formula, R １ represents a hydrocarbon group having 3 to 22 carbon atoms. (In the formula, R ２represents a hydrocarbon group having 1 to 20 carbon atoms and containing a heteroatom.) [2] The oil-in-water emulsion composition according to [1], wherein the polyaspartic acid derivative further contains succinimide monomer units C-U represented by the following formula (3), and the ratio of the total content (mol %) of the monomer units A-U and B-U to the content (mol %) of the monomer units C-U in the polyaspartic acid derivative, [(A-U)+(B-U)] / (C-U), is 80 / 20 to 99 / 1: [3] The oil-in-water emulsion composition according to [1] or [2], wherein the polyaspartic acid derivative further contains an α- or β-aspartic acid monomer unit Crosslink-U represented by the following formula (4): (In the formula, the wavy lines indicate crosslinking sites.) [4] The oil-in-water emulsion composition according to [3], wherein the content of the Crosslink-U monomer unit in the polyaspartic acid derivative is 0.1 mol % to 2.0 mol %. [5] The oil-in-water emulsion composition according to any one of [1] to [4], wherein the hydroxyl value of the polyaspartic acid derivative is 80 mg KOH / g to 170 mg KOH / g. [6] The oil-in-water emulsion composition according to any one of [1] to [5], wherein the content of the polyaspartic acid derivative is 0.1 wt % to 2.0 wt % based on the total amount of the oil-in-water emulsion composition. [7] The oil-in-water emulsion composition according to any one of [1] to [6], further comprising an emulsifier. [8] The oil-in-water emulsion composition according to [7], wherein the content of the emulsifier is 0.5 wt % to 15.0 wt % based on the total amount of the oil-in-water emulsion composition. [9] The oil-in-water emulsion composition according to [7] or [8], wherein the emulsifier is one or more selected from the group consisting of nonionic surfactants and amphoteric surfactants.

[10] The oil-in-water emulsion composition according to [9], wherein the nonionic surfactant is one or more selected from the group consisting of polyglycerin fatty acid esters, glycerin fatty acid esters, and sorbitan fatty acid esters.

[11] The oil-in-water emulsion composition according to [9] or

[10] , wherein the amphoteric surfactant is optionally hydrogenated lecithin.

[12] The oil-in-water emulsion composition according to any one of [1] to

[11] , wherein the content of the oily component relative to the total amount of the oil-in-water emulsion composition is 1.0% by weight to 50.0% by weight.

[13] The oil-in-water emulsion composition according to any one of [1] to

[12] , wherein the oil-in-water emulsion composition is a topical skin preparation.

[14] The oil-in-water emulsion composition according to

[13] , wherein the oil-in-water emulsion composition is a cosmetic.

[15] The oil-in-water emulsion composition according to

[13] or

[14] , wherein the oil-in-water emulsion composition is a cream or emulsion.

[0008] According to the present disclosure, it is possible to provide an oil-in-water emulsion composition that contains a thickener that has a low environmental impact and has sufficient viscosity.

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

[0010] Unless otherwise specified, the expressions "XX to YY" or "XX to YY" representing a range of values ​​mean a range of values ​​including the lower and upper limits, which are the endpoints. When a range of values ​​is described in stages, the upper and lower limits of each range can be combined in any way.

[0011] Hereinafter, each component contained in the oil-in-water emulsion composition according to one embodiment of the present disclosure (hereinafter also simply referred to as the "composition of the present disclosure" or "composition") will be described.

[0012] [Polyaspartic Acid Derivative] The composition of the present disclosure contains a polyaspartic acid derivative. The polyaspartic acid derivative can function as a thickener and, since it is a biodegradable polymer, has a low environmental impact. The polyaspartic acid derivative may also function as an emulsifier. The polyaspartic acid derivative contains α- or β-aspartic acid monomer units A-U (also referred to as "monomer units A-U") represented by the following general formula (1) and α- or β-aspartic acid monomer units B-U (also referred to as "monomer units B-U") represented by the following general formula (2). That is, the polyaspartic acid derivative contains the monomer units A-U and B-U as repeating units. In the present disclosure, "polyaspartic acid" includes polymers obtained by peptide condensation polymerization of aspartic acid. In the composition of the present disclosure, one type of polyaspartic acid derivative may be used alone, or two or more types may be used in combination.

[0013] (In the formula, R １ represents a hydrocarbon group having 3 to 22 carbon atoms.

[0014] (In the formula, R ２ represents a hydrocarbon group containing a heteroatom and having 1 to 20 carbon atoms.

[0015] By using a polyaspartic acid derivative, it is possible to obtain an oil-in-water emulsion composition with high viscosity. Furthermore, by using a polyaspartic acid derivative, it is possible to reduce the emulsion particle size, and therefore it is possible to obtain an oil-in-water emulsion composition with high emulsion stability. It is presumed that the above-mentioned effect can be obtained by including a polyaspartic acid derivative in an oil-in-water emulsion composition because the polyaspartic acid derivative can form hard emulsion particles while improving the viscosity of the aqueous phase. The reason why the polyaspartic acid derivative can improve the viscosity of the aqueous phase is that the polyaspartic acid derivative has an R structure of the monomer units A-U in the molecule. １ and R of the monomer unit B-U ２ In the aqueous phase, the polyaspartic acid derivative contains a group represented by R １ and having an intramolecular interaction point between groups represented by R １ When the number of groups represented by R is not too large, intermolecular interactions are promoted and thickening power is obtained (R １ If there are too many groups represented by R, particles form with just one molecule, and the intermolecular interaction decreases, resulting in a smaller thickening power. ２ While providing hydrophilicity by the group represented by ２ When the number of groups represented by R is not too large, hydrolysis of the main chain of the polyaspartic acid derivative can be suppressed, and viscosity stability is maintained. １ and a group represented by R ２The presence of an appropriate balance of groups represented by the formula (I) and (II) is believed to enable the polyaspartic acid derivative to improve and maintain the viscosity of the aqueous phase, thereby improving the viscosity of the oil-in-water emulsion composition. It is also believed that the reason for the formation of hard emulsion particles is that the polyaspartic acid derivative is oriented not only in the aqueous phase but also at the interface between the aqueous and oil phases, thereby forming stable emulsion particles. For the same reason, the formation of emulsion particles with small particle sizes can suppress viscosity reduction over long-term storage, improving viscosity stability. Furthermore, when the composition of the present disclosure is used as an external skin preparation, particularly in the form of a cream or emulsion, it provides a sensation of quickly disintegrating as if melting when applied to the skin with the fingers. It is believed that this sensation is provided by the polyaspartic acid derivative present in the external aqueous phase.

[0016] The monomer unit A-U is a unit obtained by ring-opening of the imide ring in the succinimide monomer unit of polysuccinimide through a reaction between amine A and polysuccinimide, which are used in the production method of polyaspartic acid derivatives described below. The monomer unit B-U is a unit obtained by ring-opening of the imide ring in the succinimide monomer unit of polysuccinimide through a reaction between amine B and polysuccinimide, which are used in the production method of polyaspartic acid derivatives described below.

[0017] In general formula (1), R １is not particularly limited as long as it is a hydrocarbon group having 3 to 22 carbon atoms, and the hydrocarbon group having 3 to 22 carbon atoms may be saturated or unsaturated, and may be branched or linear. Specific examples of hydrocarbon groups having 3 to 22 carbon atoms include linear alkyl groups such as propyl, butyl, pentyl, hexyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl, 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. Of these, linear or branched alkyl groups are preferred as hydrocarbon groups having 3 to 22 carbon atoms.

[0018] The number of carbon atoms in the hydrocarbon group having 3 to 22 carbon atoms is 3 or more, preferably 4 or more, more preferably 5 or more, even more preferably 6 or more, even more preferably 7 or more, even more preferably 8 or more, even more preferably 9 or more, even more preferably 10 or more, and still more preferably 11 or more. On the other hand, the number of carbon atoms in the hydrocarbon group having 3 to 22 carbon atoms is 22 or less, preferably 21 or less, more preferably 20 or less, even more preferably 19 or less, even more preferably 18 or less, even more preferably 17 or less, even more preferably 16 or less, even more preferably 15 or less, and still more preferably 14 or less. The number of carbon atoms in the hydrocarbon group having 3 to 22 carbon atoms is specifically, for example, 3 to 22, 4 to 21, 5 to 20, 6 to 19, 7 to 18, 8 to 17, 9 to 16, 10 to 15, or 11 to 14.

[0019] The monomer units AU contained in one molecule of the polyaspartic acid derivative may be of one type alone or of two or more types.

[0020] The content of the monomer units A-U in the monomer units constituting the polyaspartic acid derivative is preferably 40 mol% or more, more preferably 43 mol% or more, and even more preferably 45 mol% or more. On the other hand, the content of the monomer units A-U in the monomer units constituting the polyaspartic acid derivative is preferably 60 mol% or less, more preferably 58 mol% or less, and even more preferably 57 mol% or less. Specifically, the content of the monomer units A-U in the monomer units constituting the polyaspartic acid derivative is, for example, 40 mol% to 60 mol%, 43 mol% to 58 mol%, or 45 mol% to 57 mol%. The content of the monomer units A-U in the monomer units constituting the polyaspartic acid derivative can be adjusted by the amount of amine A and other raw materials charged. In the present disclosure, the term "monomer units constituting a polyaspartic acid derivative" refers to, among the monomer units constituting a polyaspartic acid derivative, monomer units derived from succinimide monomer units of polysuccinimide (specifically, monomer units A-U, B-U, C-U, and Crosslink-U, as well as monomer units derived from succinimide monomer units of other polysuccinimide that do not fall under these monomer units).

[0021] The content of the monomer units A-U is １ Specifically, the obtained １ The content of the monomer unit A-U (mol %) is calculated using the H-NMR spectrum according to the following formula: Content (mol %) of the monomer unit A-U = (peak integral value of the methyl group derived from amine A / 3) × 100 / ((peak integral value of the methyl group derived from amine A / 3) + (peak integral value of the methylene group derived from amine B / 2) + (peak integral value of the methine group of the succinimide monomer unit)).

[0022] The content of the monomer units A-U can also be calculated by the method described in the Examples below. That is, the content of the monomer units A-U can also be calculated from the ratio (%) of the amount (mol) of amine A charged to the amount (mol) of polysuccinimide charged in the method for producing a polyaspartic acid derivative described below. In the present disclosure, the term "amount (mol) of polysuccinimide charged" refers to the value obtained by dividing the weight of the polysuccinimide charged by the molecular weight of the repeating unit of polysuccinimide.

[0023] In general formula (2), R ２is not particularly limited as long as it is a hydrocarbon group having 1 to 20 carbon atoms and containing a heteroatom. The hydrocarbon group having 1 to 20 carbon atoms may be saturated or unsaturated, and may be branched or linear. Examples of the heteroatom include one or more selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom. Examples of the hydrocarbon group having 1 to 20 carbon atoms and containing a heteroatom include hydrophilic saturated or unsaturated hydrocarbon groups containing a nitrogen atom, an oxygen atom, a sulfur atom, or the like. Specific examples of the hydrocarbon group having 1 to 20 carbon atoms and containing a hetero atom 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; azaalkyl groups such as an azapropyl group, an azabutyl group, an azapentyl group, an azahexyl group, an N,N-dimethylaminobutyl group, an N,N-dimethylaminopropyl group, an N,N-dimethylaminoethyl group, 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; 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-dimethylaminomethyl group, and an N,N-dimethylaminomethyl group; azaalkenyl groups such as aminohexenyl group and N,N-diethylaminopropenyl group; oxaalkyl groups such as oxaethyl group, oxapropyl group, oxabutyl group, oxapentyl group, oxahexyl group, oxaheptyl group and oxaoctyl group; oxaalkyl groups such as oxapropenyl group, oxabutenyl group, oxopentenyl group, oxahexenyl group, oxaheptenyl group and oxaoctenyl group; thioalkyl groups such as thiobutyl group, thiopentyl group, thiohexyl group, thioheptyl group and thiooctyl group; thioalkenyl groups such as thiopentenyl group, thiohexenyl group, thioheptenyl group and thiooctenyl group; hydroxyalkoxyalkyl groups such as hydroxyethoxyethyl group, hydroxyethoxypropyl group, hydroxyethoxybutyl group, hydroxypropoxyethyl group, hydroxypropoxypropyl group and hydroxypropoxybutyl group;Alkoxyalkoxyalkyl groups such as methoxyethoxyethyl group, methoxyethoxypropyl group, methoxyethoxybutyl group, methoxypropoxyethyl group, methoxypropoxypropyl group, and methoxypropoxybutyl group; alkoxyalkyl groups such as methoxymethyl group, methoxyethyl group, methoxypropyl group, methoxybutyl group, methoxypentyl group, ethoxymethyl group, ethoxyethyl group, ethoxypropyl group, ethoxybutyl group, and ethoxypentyl group; dihydroxyalkyl groups such as dihydroxyethyl group, dihydroxypropyl group, and dihydroxybutyl group; amino groups (-NH) from D-glucamine; ２ -) excluding polyhydroxyalkyl groups; and the like.

[0024] The number of carbon atoms in the hydrocarbon group having 1 to 20 carbon atoms and containing a heteroatom is 1 or more, preferably 2 or more. On the other hand, the number of carbon atoms in the hydrocarbon group having 1 to 20 carbon atoms and containing a heteroatom is 20 or less, preferably 18 or less, more preferably 16 or less, even more preferably 14 or less, even more preferably 12 or less, even more preferably 10 or less, even more preferably 8 or less, and still more preferably 6 or less. The number of carbon atoms in the hydrocarbon group having 1 to 20 carbon atoms and containing a heteroatom is specifically, for example, 1 to 20, 1 to 18, 1 to 16, 1 to 14, 1 to 12, 1 to 10, 2 to 8, or 2 to 6.

[0025] R ２ 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 hydroxyhexyl 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.

[0026] R ２Hydroxyalkyl groups are more preferred. Examples of hydroxyalkyl groups include a hydroxyethyl group, a hydroxypropyl group, a hydroxybutyl group, a hydroxypentyl group, and a hydroxyhexyl group.

[0027] The monomer unit BU contained in one molecule of the polyaspartic acid derivative may be of one type alone or of two or more types.

[0028] The content of the monomer units B-U in the monomer units constituting the polyaspartic acid derivative is preferably 30 mol% or more, more preferably 32 mol% or more, and even more preferably 35 mol% or more. On the other hand, the content of the monomer units B-U in the monomer units constituting the polyaspartic acid derivative is preferably 60 mol% or less, more preferably 50 mol% or less, and even more preferably 45 mol% or less. Specific examples of the content of the monomer units B-U in the monomer units constituting the polyaspartic acid derivative are 30 mol% to 60 mol%, 32 mol% to 50 mol%, or 35 mol% to 45 mol%. The content of the monomer units B-U in the monomer units constituting the polyaspartic acid derivative can be adjusted by the amounts of amine B and other raw materials used in the production method for the polyaspartic acid derivative described below.

[0029] The content of the monomer unit B-U is １ Specifically, the obtained １ The content of the monomer unit B-U (mol %) is calculated using the H-NMR spectrum according to the following formula: Content (mol %) of the monomer unit B-U = (peak integral value of the methylene group derived from amine B / 2) × 100 / ((peak integral value of the methyl group derived from amine A / 3) + (peak integral value of the methylene group derived from amine B / 2) + (peak integral value of the methine group of the succinimide monomer unit)).

[0030] The content of the monomer units B-U can also be calculated by the method described in the Examples below, i.e., the content of the monomer units B-U can also be calculated from the ratio (%) of the amount (mol) of the amine B charged to the amount (mol) of the polysuccinimide charged.

[0031] In the polyaspartic acid derivative, the ratio of the content (mol %) of the monomer units A-U to the mol % of the monomer units B-U (also represented as (A-U) / (B-U)) is 40 / 60 to 60 / 40, preferably 45 / 55 to 60 / 40, and more preferably 50 / 50 to 60 / 40. If it is in the above range, the compatibility with water and viscosity are improved. In the present disclosure, the ratio is １ It refers to a value calculated from H-NMR. １ The detailed calculation method from H-NMR will be explained in the section (Calculation of composition ratio and hydroxyl value of polyaspartic acid derivative 1) in the Examples.

[0032] The polyaspartic acid derivative preferably further contains succinimide monomer units C-U (also referred to as "monomer units C-U") represented by the following formula (3): That is, the polyaspartic acid derivative preferably contains monomer units A-U, B-U, and C-U as repeating units. The monomer units C-U are unreacted imide rings remaining in the ring-opening reaction of polysuccinimide in the production method for polyaspartic acid derivatives described below.

[0033]

[0034] In the polyaspartic acid derivative, the ratio (mol %) of the total content (mol %) of the monomer units A-U and B-U to the content (mol %) of the monomer units C-U (also represented as [(A-U) + (B-U)] / (C-U)) is 80 / 20 to 99 / 1, preferably 85 / 15 to 98 / 1, more preferably 90 / 10 to 98 / 2, and even more preferably 90 / 10 to 97 / 2. In the present disclosure, the ratio is １ It refers to a value calculated from H-NMR. １ The detailed calculation method from H-NMR will be explained in the section (Calculation of composition ratio and hydroxyl value of polyaspartic acid derivative 1) in the Examples.

[0035] The polyaspartic acid derivative preferably further contains an α- or β-aspartic acid monomer unit Crosslink-U (also referred to as a "monomer unit Crosslink-U") represented by the following formula (4). That is, the polyaspartic acid derivative preferably contains the monomer units A-U, B-U, and Crosslink-U as repeating units. Furthermore, the polyaspartic acid derivative more preferably contains the monomer units A-U, B-U, C-U, and Crosslink-U. That is, the polyaspartic acid derivative more preferably contains the monomer units A-U, B-U, C-U, and Crosslink-U as repeating units. The monomer unit Crosslink-U is a unit formed by opening the imide ring in the succinimide monomer unit of polysuccinimide through a reaction between the polysuccinimide and a crosslinking agent used in the production method of a polyaspartic acid derivative described below.

[0036] (In the formula, the wavy lines indicate crosslinking sites.)

[0037] When the polyaspartic acid derivative contains the Crosslink-U monomer unit, the polyaspartic acid derivative is preferably a slightly crosslinked modified polyaspartic acid derivative. Here, "slightly crosslinked modified polyaspartic acid derivative" refers to a modified polyaspartic acid derivative having a crosslinking amount of 0.1 mol % to 2.0 mol %. "Slightly crosslinked" is to be distinguished from ordinary "crosslinked" polymers, which have a crosslinking amount of more than 2.0 mol %. For example, because the amount of crosslinking is small, slightly crosslinked polymers do not gel in solutions of a given concentration and tend to maintain a certain level of fluidity.

[0038] When the polyaspartic acid derivative contains the monomer unit Crosslink-U, the crosslinking amount in the polyaspartic acid derivative (i.e., the content of the monomer unit Crosslink-U in the constituent monomers of the polyaspartic acid derivative) is preferably 0.1 mol% or more, more preferably 0.3 mol% or more, and even more preferably 0.5 mol% or more. On the other hand, the crosslinking amount in the polyaspartic acid derivative is preferably 2.0 mol% or less, more preferably 1.8 mol% or less, and even more preferably 1.7 mol% or less. Specific examples of the crosslinking amount in the polyaspartic acid derivative are 0.1 mol% to 2.0 mol%, 0.3 mol% to 1.8 mol%, or 0.5 mol% to 1.7 mol%. The crosslinking amount can be adjusted by the amount of crosslinking agent charged and the amount of each other raw material charged. The crosslinking amount can be calculated from the ratio (%) of the amount of crosslinking agent charged (mol) to the amount of polysuccinimide charged (mol).

[0039] The bonding form of the monomer units A-U, B-U, C-U, and Crosslink-U may be any of random, block, and tapered. The bonding form of each of these monomer units may be any of linear, macrocyclic, branched, star, and three-dimensional network, but is preferably linear.

[0040] The polyaspartic acid derivative may contain other monomer units besides the monomer units A-U, B-U, C-U, and Crosslink-U, to the extent that the effects of the present disclosure are not significantly impaired. The other monomer units are monomer units derived from the succinimide monomer units of polysuccinimide that do not fall under the monomer units A-U, B-U, C-U, and Crosslink-U. Examples of the other monomer units include units formed by ring-opening of the imide ring in the succinimide monomer unit of polysuccinimide through a reaction between another monoamine described below and polysuccinimide.

[0041] The hydroxyl value of the polyaspartic acid derivative is preferably 80 mgKOH / g or more, more preferably 100 mgKOH / g or more. On the other hand, the hydroxyl value of the polyaspartic acid derivative is preferably 170 mgKOH / g or less, more preferably 150 mgKOH / g or less, even more preferably 120 mgKOH / g or less, and even more preferably 110 mgKOH / g or less. Specifically, the hydroxyl value of the polyaspartic acid derivative is, for example, 80 mgKOH / g to 170 mgKOH / g, 100 mgKOH / g to 150 mgKOH / g, 80 mgKOH / g to 120 mgKOH / g, or 100 mgKOH / g to 110 mgKOH / g. The hydroxyl value can be adjusted by the amounts of amine A and amine B charged. The method for calculating the hydroxyl value is explained in the section (Calculation of the composition ratio and hydroxyl value of polyaspartic acid derivative 1) in the Examples.

[0042] The weight-average molecular weight (Mw) of the polyaspartic acid derivative is not particularly limited, but is preferably 80,000 or more, more preferably 100,000 or more, and even more preferably 120,000 or more. The weight-average molecular weight of the polyaspartic acid derivative is preferably 700,000 or less, more preferably 600,000 or less, even more preferably 500,000 or less, even more preferably 300,000 or less, even more preferably 200,000 or less, and even more preferably 170,000 or less. Specifically, the weight-average molecular weight of the polyaspartic acid derivative is, for example, 80,000 to 700,000, 100,000 to 600,000, 120,000 to 500,000, 80,000 to 300,000, 100,000 to 200,000, or 120,000 to 170,000. The weight-average molecular weight of the polyaspartic acid derivative can be adjusted by the molecular weight of the polysuccinimide used in the production method of the polyaspartic acid derivative described below, and the types of amine A and amine B. The weight-average molecular weight herein refers to a converted value measured by a GPC method (differential refractometer) using polystyrene as a standard substance, and specifically refers to a weight-average molecular weight measured using a G1000HHR column (TSKgel (registered trademark), manufactured by Tosoh Corporation), a G4000HHR column (TSKgel (registered trademark), manufactured by Tosoh Corporation), or a GMHHR-H column (TSKgel (registered trademark), manufactured by Tosoh Corporation) using dimethylformamide containing 10 mM lithium bromide as an eluent.

[0043] The polyaspartic acid derivative can be obtained by ring-opening polysuccinimide using amine A and amine B, which will be described later. When the polyaspartic acid derivative contains the monomer unit Crosslink-U, the polyaspartic acid derivative can be obtained by ring-opening polysuccinimide using amine A and amine B, and then forming a crosslinked moiety with a crosslinking agent. In the ring-opening reaction of polysuccinimide, unreacted imide rings may remain. In this case, the compound of the present disclosure further contains the monomer unit C-U.

[0044] [Polysuccinimide (PSI)] Polysuccinimide (PSI) is a polymer represented by the following formula (5): The repeating unit in formula (5) is the same as the monomer unit CU.

[0045] (In the formula, n=10 to 10000)

[0046] The method for producing polysuccinimide (PSI) is not particularly limited. For example, it can be produced by dehydration condensation of aspartic acid while heating at 170 to 190°C in a vacuum in the presence of phosphoric acid. To produce a polysuccinimide with a higher molecular weight, the polysuccinimide obtained as described above can be treated with a condensing agent such as dicyclohexylcarbodiimide. The molecular weight of the polysuccinimide is not particularly limited. For example, the weight-average molecular weight of the polysuccinimide is preferably 20,000 or more, more preferably 50,000 or more, and even more preferably 70,000 or more. On the other hand, the weight-average molecular weight of the polysuccinimide is preferably 500,000 or less, and more preferably 200,000 or less. Specifically, the weight-average molecular weight of the polysuccinimide is, for example, 20,000 to 500,000, 50,000 to 500,000, or 70,000 to 200,000. The weight-average molecular weight herein refers to a converted value measured by a GPC method (differential refractometer) using polystyrene as a standard substance, and specifically refers to a weight-average molecular weight measured using a G1000HHR column (TSKgel (registered trademark), manufactured by Tosoh Corporation), a G4000HHR column (TSKgel (registered trademark), manufactured by Tosoh Corporation), or a GMHHR-H column (TSKgel (registered trademark), manufactured by Tosoh Corporation) using dimethylformamide containing 10 mM lithium bromide as an eluent.

[0047] [Crosslinking Agent] The crosslinking agent is not particularly limited as long as it can form a crosslinked moiety. Specific examples of crosslinking agents preferred for forming an amide bond used in the crosslinked moiety include polyfunctional amines.

[0048] The polyfunctional amine is preferably an amine having at least two primary and / or secondary amino groups. Examples of diamines include aliphatic diamines such as ethylenediamine and hexamethylenediamine, and aliphatic diamines containing an aromatic ring 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 an amino group in the side chain, such as lysine and ornithine; monoamino compounds linked by disulfide bonds, such as cystine and cystamine, and derivatives thereof. The polyfunctional amine preferably does not contain the above amino acids and derivatives thereof. The polyfunctional amine is preferably an ether-based diamine, as described above, from the viewpoint of having a flexible structure, making it difficult for insoluble matter to be generated during the crosslinking reaction, and from the viewpoint of making the crosslinking reaction easy to control.

[0049] Examples of polyfunctional amines other than diamines include tris(2-aminoalkyl)amines (wherein the alkyl preferably has 1 to 5 carbon atoms, and more preferably 2 to 4 carbon atoms), such as tris(2-aminoethyl)amine (TREN) and tris(3-aminopropyl)amine; and polyethylene polyamines, such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

[0050] Among these, preferred examples of polyfunctional amines include 1,2-bis(2-aminoethoxy)ethane (AEE), bis[2-(3-aminopropoxy)ethyl]ether (APEE), and tris(2-aminoethyl)amine (TREN).

[0051] One method for reacting polysuccinimide with a polyfunctional amine is, for example, a method in which the reaction is carried out in an organic solvent. This method will be described using a preferred example in which the polyfunctional amine is a diamine, but the reaction conditions and procedures, such as the type of organic solvent, are not limited to those described below. In a method for reacting polysuccinimide with a diamine in an organic solvent, polysuccinimide is dissolved in an organic solvent (preferably an aprotic polar organic solvent) such as dimethylformamide (DMF), dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethylimidazolidinone (DMI), dimethyl sulfoxide (DMSO), or sulfolane to prepare a polysuccinimide solution, and then a diamine or a solution of a diamine in the organic solvent is added dropwise to the polysuccinimide solution. The amount of organic solvent used to dissolve the polysuccinimide is not particularly limited, but is typically adjusted to a polymer concentration of 1 to 50% by mass.

[0052] The temperature at which the polysuccinimide and the diamine are reacted is not particularly limited, but is, for example, room temperature to 80° C. In the present disclosure, "room temperature" refers to a temperature condition in which no external heating or cooling is performed, and specifically, is 15° C. to 30° C.

[0053] The reaction conditions (reaction temperature, reaction time, reaction concentration, amount of diamine used, etc.) are not particularly limited, but it is desirable to set the conditions such that the entire reaction solution does not gel.

[0054] [Amine A and Amine B] A primary amine represented by the following general formula (6) is used as the amine A: １ -NH ２ (6) (wherein, R １ represents a hydrocarbon group having 3 to 22 carbon atoms.

[0055] A primary amine represented by the following general formula (7) is used as the amine B: ２ -NH ２ (7) (wherein, R ２ represents a hydrocarbon group containing a heteroatom and having 1 to 20 carbon atoms.

[0056] R in general formula (6) １Regarding R in general formula (1), １ The explanation regarding R in general formula (7) is also incorporated herein by reference. ２ Regarding R in general formula (2), ２ The amine A and the amine B (collectively referred to as "monoamines") may be commercially available products or products prepared by known methods.

[0057] Examples of amine A include linear alkylamines such as propylamine, butylamine, pentylamine, hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine, hexadecylamine, and octadecylamine; branched alkylamines such as isopropylamine, isobutyl group, isopentylamine, and isohexylamine; cycloalkylamine groups such as cyclobutylamine, cyclopentylamine, and cyclohexylamine; (cycloalkylalkyl)amines such as (cyclobutylmethyl)amine, (cyclopentylmethyl)amine, (cyclohexylmethyl)amine, (cyclobutylethyl)amine, (cyclopentylethyl)amine, (cyclohexylethyl)amine, (cyclobutylpropyl)amine, (cyclopentylpropyl)amine, (cyclohexylpropyl)amine, (cyclobutylbutyl)amine, (cyclopentylbutyl)amine, and (cyclohexylbutyl)amine; and alkenylamines such as propenylamine, butenylamine, pentenylamine, and hexenylamine. Of these, the amine A is preferably an amine selected from the group consisting of linear alkylamines and branched alkylamines.

[0058] Examples of amine B include hydroxyalkylamines such as hydroxymethylamine, hydroxyethylamine, hydroxypropylamine, hydroxybutylamine, hydroxypentylamine, hydroxyhexylamine, hydroxyheptylamine, and hydroxyoctylamine; azapropylamine, azabutylamine, azapentylamine, azahexylamine, (N,N-dimethylaminobutyl)amine, (N,N-dimethylaminopropyl)amine, (N,N-dimethylaminoethyl)amine, and the like. azaalkylamines such as (N,N-dimethylaminomethyl)amine, (N,N-diethylaminobutyl)amine, (N,N-diethylaminopropyl)amine, (N,N-diethylaminoethyl)amine, and (N,N-diethylaminomethyl)amine; azaalkylamines such as azapropenylamine, azabutenylamine, azapentenylamine, azahexenylamine, (N,N-dimethylaminopropenyl)amine, (N,N-dimethylaminobutenyl)amine, (N,N-dimethylaminohexenyl)amine, and (N,N-diethylaminomethyl)amine; azaalkenylamines such as (hydroxyethoxy)ethylamine, oxapropylamine, oxabutylamine, oxapentylamine, oxahexylamine, oxaheptylamine, and oxaoctylamine; oxaalkylamines such as oxapropenylamine, oxabutenylamine, oxopentenylamine, oxahexenylamine, oxaheptenylamine, and oxaoctenylamine; thioalkylamines such as thiobutylamine, thiopentylamine, thiohexylamine, thioheptylamine, and thiooctylamine; thioalkenylamines such as thiopentenylamine, thiohexenylamine, thioheptenylamine, and thiooctenylamine; [(hydroxyalkoxy)alkyl]amines such as [(hydroxyethoxy)ethyl]amine, [(hydroxyethoxy)propyl]amine, [(hydroxyethoxy)butyl]amine, [(hydroxypropoxy)ethyl]amine, [(hydroxypropoxy)propyl]amine, and [(hydroxypropoxy)butyl]amine;Examples include [(alkoxyalkoxy)alkyl]amines such as [(methoxyethoxy)ethyl]amine, [(methoxyethoxy)propyl]amine, [(methoxyethoxy)butyl]amine, [(methoxypropoxy)ethyl]amine, [(methoxypropoxy)propyl]amine, and [(methoxypropoxy)butyl]amine; alkoxyalkylamines such as methoxymethylamine, methoxyethylamine, methoxypropylamine, methoxybutylamine, methoxypentylamine, ethoxymethylamine, ethoxyethylamine, ethoxypropylamine, ethoxybutylamine, and ethoxypentylamine; dihydroxyalkylamines such as dihydroxyethylamine, dihydroxypropylamine, and dihydroxybutylamine; and polyhydroxyalkylamines such as D-glucamine. Among these, amine B is preferably an amine selected from the group consisting of (N,N-dimethylaminopropyl)amine, (N,N-diethylaminopropyl)amine, hydroxymethylamine, hydroxyethylamine, hydroxypropylamine, hydroxybutylamine, hydroxypentylamine, hydroxyhexylamine, [(hydroxyethoxy)ethyl]amine, methoxymethylamine, methoxyethylamine, methoxypropylamine, methoxybutylamine, methoxypentylamine, ethoxymethylamine, ethoxyethylamine, ethoxypropylamine, ethoxybutylamine, ethoxypentylamine, and dihydroxypropylamine, and more preferably an amine selected from the group consisting of hydroxyethylamine, hydroxypropylamine, hydroxybutylamine, hydroxypentylamine, and hydroxyhexylamine;

[0059] The amine A and the amine B may each be used alone or in combination of two or more thereof.

[0060] [Method for Producing Polyaspartic Acid Derivatives] Examples of methods for producing polyaspartic acid derivatives include a method for ring-opening reaction of polysuccinimide using polysuccinimide and a monoamine. Furthermore, when the polyaspartic acid derivative contains the monomer unit Crosslink-U, a crosslinking agent such as a polyfunctional amine is used in addition to the polysuccinimide and monoamine in the ring-opening reaction of the polysuccinimide. The order of addition of the crosslinking agent and monoamine is not particularly limited. The monoamine may be added first and then the crosslinking agent, or the monoamine and 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 crosslinking amount, it is preferable to add the crosslinking agent first, allow the crosslinking reaction to proceed, and then add the monoamine. The order of addition of amine A and amine B is also not particularly limited. For example, amine A may be added first and then amine B, or amine A and amine B may be added simultaneously, or amine B may be added first and then amine A.

[0061] Specifically, when a polyfunctional amine is used as a crosslinking agent, the method for producing a polyaspartic acid derivative may involve, if necessary, reacting a polysuccinimide with the crosslinking agent to form a crosslinked structure, followed by reaction with a monoamine to open the imide ring of the polysuccinimide. The total amount of the crosslinking agent and the monoamine used may be less than 1 molar equivalent relative to the molar equivalent of the monomer unit of the polysuccinimide, so that unreacted imide rings remain, or may be 1 molar equivalent or more, so that unreacted imide rings do not remain.

[0062] The unreacted imide ring may remain as it is, or may be opened by reaction with a primary or secondary monoamine other than amine A and amine B (for example, a substituted amine such as cysteamine or dibutylamine).

[0063] In the method for producing a polyaspartic acid derivative, the amount of amine A charged relative to the amount of polysuccinimide charged is preferably 40 mol% or more, more preferably 43 mol% or more, and even more preferably 45 mol% or more. On the other hand, the amount of amine A charged relative to the amount of polysuccinimide charged is preferably 60 mol% or less, more preferably 58 mol% or less, and even more preferably 57 mol% or less. Specifically, the amount of amine A charged relative to the amount of polysuccinimide charged is, for example, 40 mol% to 60 mol%, 43 mol% to 58 mol%, or 45 mol% to 57 mol%.

[0064] In the method for producing a polyaspartic acid derivative, the amount of amine B charged relative to the amount of polysuccinimide charged is preferably 30 mol% or more, more preferably 32 mol% or more, and even more preferably 35 mol% or more. On the other hand, the amount of amine B charged relative to the amount of polysuccinimide charged is preferably 60 mol% or less, more preferably 50 mol% or less, and even more preferably 45 mol% or less. Specifically, the amount of amine B charged relative to the amount of polysuccinimide charged is, for example, 30 mol% to 60 mol%, 32 mol% to 50 mol%, or 35 mol% to 45 mol%.

[0065] In the method for producing a polyaspartic acid derivative, the amount of crosslinking agent charged relative to the amount of polysuccinimide charged is preferably 0.1 mol% or more, more preferably 0.3 mol% or more, and even more preferably 0.5 mol% or more. On the other hand, the amount of crosslinking agent charged relative to the amount of polysuccinimide charged is preferably 2.0 mol% or less, more preferably 1.8 mol% or less, and even more preferably 1.7 mol% or less. Specifically, the amount of polysuccinimide charged relative to the amount of crosslinking agent charged is, for example, 0.1 mol% to 2.0 mol%, 0.3 mol% to 1.8 mol%, or 0.5 mol% to 1.7 mol%.

[0066] In the method for producing a polyaspartic acid derivative, a primary or secondary monoamine other than amine A and amine B (hereinafter also referred to as "other monoamine") may be used. In this case, the total amount of amine A and amine B relative to the total amount of amine A, amine B, and other monoamines is preferably 80.0 mol% or more, more preferably 90.0 mol% or more, and even more preferably 95.0 mol% or more. On the other hand, the total amount of amine A and amine B relative to the total amount of amine A, amine B, and other monoamines is less than 100.0 mol%. Examples of other monoamines include substituted amines such as cysteamine and dibutylamine.

[0067] The total amount of amine A, amine B, and other monoamines charged is not particularly limited as long as they are substantially soluble in the organic solvent and / or do not substantially inhibit the progress of the reaction. The charged amounts are generally 0.1 or more molar equivalents relative to the molar equivalents of the monomer units of polysuccinimide. On the other hand, the charged amounts are generally 10 or less molar equivalents relative to the molar equivalents of the monomer units of polysuccinimide, and preferably 1.2 or less molar equivalents. Specifically, the charged amounts relative to the molar equivalents of the monomer units of polysuccinimide are, for example, 0.1 to 10 molar equivalents, and preferably 0.1 to 1.2 molar equivalents.

[0068] In the method for producing a polyaspartic acid derivative, the molar ratio of the amount of amine A charged to the amount of amine B charged is preferably 45 / 55 to 60 / 40, and more preferably 50 / 50 to 60 / 40.

[0069] [Organic Solvent] In the method for producing a polyaspartic acid derivative, the organic solvent used in each of the crosslinking reaction and the ring-opening reaction is not particularly limited as long as it substantially dissolves the polysuccinimide, the crosslinking agent, and the monoamine and / or does not substantially inhibit the progress of the reaction. The organic solvent may be used alone or in combination of two or more. In the present disclosure, the term "organic solvent" does not include amine A, amine B, other monoamines, or the basic catalyst described below.

[0070] The organic solvent may be an aprotic polar organic solvent, a protic polar organic solvent, or a mixed solvent of these in any ratio, but preferably contains an aprotic polar organic solvent. That is, the organic solvent is preferably an aprotic polar organic solvent or a mixed solvent of an aprotic polar organic solvent and a protic polar organic solvent. Specific examples of aprotic polar organic solvents include dimethylformamide (DMF), dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethylimidazolidinone (DMI), dimethyl sulfoxide (DMSO), sulfolane, etc., and preferably DMF or NMP. Specific examples of protic polar organic solvents include monohydric alcohols having 1 to 5 carbon atoms, such as methanol, ethanol, n-propanol, and isopropanol; dihydric alcohols having 1 to 8 carbon atoms, such as butylene glycol, propylene glycol, ethylene glycol, and dibutylene glycol; trihydric alcohols having 1 to 8 carbon atoms, such as glycerin; sterols, such as cholesterol, sitosterol, phytosterol, and lanosterol; monosaccharides (for example, pentoses, such as ribose, arabinose, and xylose; hexoses, such as glucose, galactose, and fructose); and sugar alcohols, such as sorbitol, xylitol, and maltitol; and the like, with monohydric alcohols having 1 to 5 carbon atoms being preferred.

[0071] [Basic Catalyst] In the method for producing a polyaspartic acid derivative, the ring-opening reaction may not require the use of a catalyst, or may involve the use of a catalyst such as a basic catalyst. The optional basic catalyst is not particularly limited as long as it substantially accelerates the reaction rate. However, in the present disclosure, the term "basic catalyst" does not include amine A, amine B, or other monoamines. Specific examples of basic catalysts include aliphatic tertiary amines such as trimethylamine, triethylamine, tripropylamine, tributylamine, diisopropylethylamine (DIEA), triethanolamine, and triethylenediamine (DABCO); alicyclic tertiary amines such as N-methylmorpholine; aromatic tertiary amines such as dimethylaniline and diethylaniline; and guanidine compounds such as tetramethylguanidine. The basic catalyst may be used alone or in combination of two or more types.

[0072] In the method for producing a polyaspartic acid derivative, the amount of the basic catalyst used in the ring-opening reaction 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 molar equivalents relative to the molar equivalent of the total amount of monoamines charged.

[0073] [Reaction Temperature] In the method for producing a polyaspartic acid derivative, the reaction temperature is not particularly limited as long as it can substantially maintain the progress of the reaction. The reaction temperature is generally selected from a temperature range of 5 to 150°C. The reaction temperature can be optimally selected from the perspective of the monoamine used, shortening the reaction time, improving the reaction rate, and the like. The method for producing a polyaspartic acid derivative preferably includes a crosslinking reaction step in which a crosslinking agent is first added and the crosslinking reaction proceeds, and a ring-opening reaction step in which a monoamine is then added and the ring-opening reaction proceeds. In this case, the temperature of the crosslinking reaction and the temperature of the monoamine reaction may be the same or different. The temperature of the crosslinking reaction is preferably 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 and the crosslinking reaction proceeds, the reaction temperature may be 120°C or lower, or 100°C or lower. The reaction temperature in the crosslinking reaction step may be 20°C or higher. Specifically, the reaction temperature in the crosslinking reaction step may be, for example, 20°C to 120°C or 20°C to 100°C. Furthermore, 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, even more preferably 60°C or lower, and may be 50°C or lower. The reaction temperature in the crosslinking reaction step may be 20°C or higher. Specifically, the reaction temperature in the crosslinking reaction step may be, for example, 20°C to 100°C, 20°C to 80°C, 20°C to 60°C, or 20°C to 50°C. In the crosslinking reaction step, crosslinking can proceed uniformly as long as the reaction temperature is within the above range. By the above production method, a polyaspartic acid derivative with high viscosity can be obtained.

[0074] [Concentration of Reaction System] The concentration of the reaction system employed in the method for producing a polyaspartic acid derivative is not particularly limited as long as it can substantially maintain the progress of the reaction. The concentration of the reaction system is selected based on the concentration of polysuccinimide, and the polysuccinimide concentration is generally selected from a concentration range of 1 to 50% by weight. The concentration of the reaction system can also be selected from a polysuccinimide concentration range of 1 to 50% by weight to be optimal for the monoamine used.

[0075] [Method for Isolating Polyaspartic Acid Derivatives] In the method for producing polyaspartic acid derivatives, the method for isolating the polymer produced from the reaction solution after the reaction is completed is not particularly limited as long as it can isolate the reaction product with the desired purity. The isolation method may be any known or commonly used method. Generally, known or commonly used isolation procedures such as concentration, recrystallization, or reprecipitation are used.

[0076] A specific example of the isolation method is a method in which, after completion of the reaction, 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, the precipitated reaction product is 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. Another specific example is a method in which, after 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 reaction product is isolated, washed, and dried in the same manner as above.

[0077] In the method for producing a polyaspartic acid derivative, the resulting polyaspartic acid derivative may not be isolated, and the post-reaction mixture may be used as is as the polyaspartic acid derivative. Alternatively, if necessary, only some of the unreacted raw materials other than the solvent may be removed and incorporated into the composition of the present disclosure. Alternatively, the solvent in the mixture may be increased or decreased to adjust the concentration and produce a polyaspartic acid derivative.

[0078] <Content of Polyaspartic Acid Derivative> The content of the polyaspartic acid derivative relative to the total amount of the composition of the present disclosure is not particularly limited and can be adjusted appropriately depending on the purpose, but is preferably 0.1 wt% or more, more preferably 0.15 wt% or more, even more preferably 0.2 wt% or more, even more preferably 0.5 wt% or more, and even more preferably 1.0 wt% or more. On the other hand, the content of the polyaspartic acid derivative relative to the total amount of the composition is preferably 2.0 wt% or less, more preferably 1.8 wt% or less, and even more preferably 1.5 wt% or less. Specifically, the content of the polyaspartic acid derivative relative to the total amount of the composition is, for example, 0.1 wt% to 2.0 wt%, 0.15 wt% to 2.0 wt%, 0.2 wt% to 1.8 wt%, 0.5 wt% to 1.5 wt%, or 1.0 wt% to 1.5 wt%.

[0079] The composition of the present disclosure has an oil-in-water (O / W) emulsion structure. That is, it has a structure in which an oil phase (O phase) is encapsulated in an aqueous phase (W phase). In the present disclosure, the aqueous phase is typically composed of water and an aqueous component. Here, the aqueous component may be a component that dissolves in water at 25 to 65°C. In the present disclosure, the oil phase is typically composed of an oily component. Here, the oily component is typically an oil agent, but is not limited thereto, and may also include a component that undergoes phase separation from water after being suspended in water at 25 to 65°C and left to stand for 1 hour.

[0080] [Oil-based component] The composition of the present disclosure contains an oil-based component. The oil-based component is not particularly limited, and known components can be used. The oil-based component may be any component that is liquid, solid, or semi-solid at room temperature. Examples of oil-based components include hydrocarbons, higher alcohols, higher fatty acids, esters, silicone oils, and vegetable oils. One type of oil-based component may be used alone, or two or more types may be used in combination. In this disclosure, "higher alcohol" refers to an alcohol having 6 or more carbon atoms, while "lower alcohol" refers to an alcohol having 5 or fewer carbon atoms. In this disclosure, "higher fatty acid" refers to a fatty acid having 8 or more carbon atoms.

[0081] Examples of hydrocarbons include squalane, mineral oil, liquid paraffin, light isoparaffin, dodecane, tetradecane, ozokerite, microcrystalline wax, ceresin, α-olefin oligomer, polybutene, hydrogenated polyisoparaffin, limonene, turpentine, and petrolatum.

[0082] Examples of higher alcohols include straight-chain or branched-chain alcohols having 8 to 24 carbon atoms, such as coconut oil alcohol, capryl alcohol, capric alcohol, lauryl alcohol, isostearyl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, cetostearyl alcohol, arachyl alcohol, behenyl alcohol, oleyl alcohol, isostearyl alcohol, hexyldecanol, 2-octyldodecanol, decyltetradecanol, and batyl alcohol; and sterols, such as cholesterol and phytosterol.

[0083] Examples of higher fatty acids include those having 8 to 24 carbon atoms, such as coconut oil fatty acid, isostearic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, undecylenic acid, oleic acid, linoleic acid, linolenic acid, arachidonic acid, oxystearic acid, palmitoleic acid, ricinoleic acid, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), isostearic acid, and 12-hydroxystearic acid.

[0084] Examples of esters include: esters of straight-chain fatty acids and lower alcohols such as isopropyl myristate, isopropyl palmitate, and ethyl oleate; esters of straight-chain fatty acids and higher alcohols such as hexyl laurate, myristyl myristate, decyl oleate, stearyl stearate, and cetyl palmitate; esters of straight-chain fatty acids and branched alcohols such as octyldodecyl myristate, isostearyl palmitate, ethylhexyl stearate, and ethylhexyl palmitate; esters of branched fatty acids and lower alcohols such as ethyl isostearate and isopropyl isostearate; esters of branched fatty acids and higher alcohols such as cetyl ethylhexanoate and hexyl isostearate; esters of fatty acids and polyhydric alcohols such as PG dicaprylate, triethylhexanoin, and tri(caprylic / capric)glyceryl; Esters of branched fatty acids and branched alcohols such as 2-octyldodecyl neopentanoate and isostearyl isostearate; esters of hydroxycarboxylic acids and alcohols such as lauryl lactate, trioctyldodecyl citrate and diisostearyl malate; ester oils such as esters of dibasic acids such as diisopropyl adipate and diethyl sebacate; wax esters such as jojoba butter, carnauba wax, candelilla wax, rice bran wax, beeswax, montan wax, sugarcane wax and palm wax; and the like.

[0085] Examples of silicone oils include dimethylpolysiloxane, methylphenylpolysiloxane, dodecamethylcyclohexasiloxane, methylhydrogenpolysiloxane, dimethylsiloxane, etc. The kinematic viscosity of the silicone oil at 25°C is not particularly limited and can be selected appropriately depending on the purpose. ２ / s or less is preferable, and 50 mm ２ / s or less is more preferable.

[0086] Examples of vegetable oils include apricot kernel oil, camellia oil, argan oil, soybean oil, olive oil, castor oil, coconut oil, palm oil, palm kernel oil, sesame oil, perilla oil, jojoba seed oil, cottonseed oil, rapeseed oil, linseed oil, rosehip oil, sunflower oil, essential oils, avocado oil, almond oil, rice bran oil, safflower oil, corn oil, grapeseed oil, coconut oil, Argania spinosa kernel oil, wheat germ oil, rice germ oil, kukui nut oil, crambe abyssinica seed oil, hemp seed oil, peanut oil, camellia oil, evening primrose oil, pistachio oil, macadamia nut oil, meadowholm oil, cocoa butter, shea butter, and Japan wax oil.

[0087] The oily component is preferably one or more selected from the group consisting of hydrocarbons, higher alcohols, esters, silicone oils, and vegetable oils.

[0088] The content of the oily component relative to the total weight of the composition of the present disclosure is not particularly limited, but is preferably 1.0 wt% or more, more preferably 5.0 wt% or more, even more preferably 10.0 wt% or more, even more preferably 15.0 wt% or more, and even more preferably 17.0 wt% or more. On the other hand, the content of the oily component relative to the total weight of the composition is preferably 50.0 wt% or less, more preferably 40.0 wt% or less, even more preferably 35.0 wt% or less, even more preferably 30.0 wt% or less, and even more preferably 25.0 wt% or less. Specifically, the content of the oily component relative to the total weight of the composition is, for example, 1.0 wt% to 50.0 wt%, 5.0 wt% to 40.0 wt%, 10.0 wt% to 35.0 wt%, 15.0 wt% to 30.0 wt%, or 17.0 wt% to 25.0 wt%.

[0089] [Water] The composition of the present disclosure contains water. The water content relative to the total amount of the composition of the present disclosure is preferably 40.0 wt% or more, more preferably 45.0 wt% or more, even more preferably 50.0 wt% or more, even more preferably 55.0 wt% or more, even more preferably 60.0 wt% or more, and even more preferably 65.0 wt% or more. On the other hand, the water content relative to the total amount of the composition is preferably 90.0 wt% or less, more preferably 85.0 wt% or less, even more preferably 80.0 wt% or less, even more preferably 75.0 wt% or less, and even more preferably 70.0 wt% or less. Specific examples of the water content relative to the total amount of the composition are 40.0 wt% to 90.0 wt%, 45.0 wt% to 85.0 wt%, 50.0 wt% to 80.0 wt%, 55.0 wt% to 75.0 wt%, 60.0 wt% to 70.0 wt%, or 65.0 wt% to 70.0 wt%.

[0090] [Emulsifier] The composition of the present disclosure preferably contains an emulsifier. Here, "emulsifier" refers to an emulsifier other than a polyaspartic acid derivative. The emulsifier is not particularly limited, and examples thereof include one or more surfactants selected from the group consisting of anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants. One type of emulsifier may be used alone, or two or more types may be used in combination.

[0091] Examples of anionic surfactants include fatty acid soaps such as potassium coconut oil fatty acid (e.g., potassium cocoyl glutamate), potassium myristate, and potassium laurate; alkyl sulfates such as potassium lauryl sulfate, sodium lauryl sulfate, triethanolamine lauryl sulfate, and sodium myristyl sulfate; polyoxyethylene lauryl ether sodium sulfate such as sodium POE(2) lauryl ether sulfate; polyoxyethylene alkyl ether sulfates such as polyoxyethylene lauryl ether triethanolamine sulfate; alkyl phosphates such as lauryl phosphate; amino acid surfactants such as acyl methyl taurate and sodium lauroyl methyl alanine; and sulfonates such as sodium lauryl sulfoacetate.

[0092] Examples of cationic surfactants include alkylammonium salts such as cetyltrimethylammonium chloride, stearyltrimethylammonium chloride (steartrimonium chloride), behenyltrimethylammonium chloride, lauryltrimethylammonium chloride, stearoxypropyltrimonium chloride, and quaternium-33; alkylbenzylammonium salts; stearylamine acetate; polyoxyethylene alkylamines such as polyoxyethylene laurylamine and polyoxyethylene stearylamine; stearamidopropyldimethylamine; and benzalkonium chloride.

[0093] Examples of nonionic surfactants include polyoxyethylene sorbitan fatty acid esters such as POE (20) sorbitan monolaurate, POE (20) sorbitan monopalmitate, POE (6) sorbitan monostearate, POE (20) sorbitan monostearate, POE (20) sorbitan tristearate, POE (6) sorbitan monooleate, POE (20) sorbitan monooleate, POE (20) sorbitan trioleate, and POE (20) sorbitan monoisostearate; polyethylene glycol fatty acid esters such as POE (10) monostearate, POE (25) monostearate, POE (40) monostearate, POE (55) monostearate, POE (10) monolaurate, POE (10) monooleate, and PEG-20 sorbitan cocoate; polyoxyethylene alkyl ethers such as POE (4) lauryl ether, POE (9) lauryl ether, POE (21) lauryl ether, POE (150) cetyl ether, POE (20) cetyl ether, POE (2) cetyl ether, POE (10) cetyl ether, POE (25) cetyl ether, POE (30) cetyl ether, POE (10) oleyl ether, POE (15) oleyl ether, POE (7) oleyl ether, POE (20) oleyl ether, POE (50) oleyl ether, POE (5) behenyl ether, POE (10) behenyl ether, POE (20) behenyl ether, POE (30) behenyl ether, and POE (20) stearyl ether; Polyoxyethylene polyoxypropylene alkyl ethers such as POE (20) POP (4) cetyl ether, POE (20) POP (8) cetyl ether, and POE (30) POP (6) decyl tetradecyl ether; polyoxyethylene sorbitol fatty acid esters such as POE (60) sorbitol tetrastearate, POE (6) sorbitol tetraoleate, POE (30) sorbitol tetraoleate, POE (60) sorbitol tetraoleate, and POE (6) sorbitol monolaurate;Polyoxyethylene glycerin fatty acid esters such as PEG-20 glyceryl triisostearate, PEG-7 glyceryl coconut oil fatty acid, POE (15) glyceryl monostearate, POE (5) glyceryl monostearate, and POE (15) glyceryl monooleate; polyoxyethylene castor oils and hydrogenated castor oils such as POE (40) castor oil, POE (20) hydrogenated castor oil, POE (40) hydrogenated castor oil, POE (50) hydrogenated castor oil, POE (60) castor oil, POE (60) hydrogenated castor oil, POE (80) hydrogenated castor oil, and POE (100) hydrogenated castor oil; polyoxyethylene lanolin alcohols such as POE (10) lanolin alcohol, POE (20) lanolin alcohol, and POE (40) lanolin alcohol; Sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan sesquistearate, sorbitan monooleate, sorbitan sesquioleate, and sorbitan trioleate; glycerin fatty acid esters such as glyceryl monooleate, glyceryl monostearate, and glyceryl monomyristate;Diglycerol fatty acid esters such as diglyceryl monostearate, diglyceryl monooleate, diglyceryl monoisostearate, etc.; triglycerol fatty acid esters such as triglyceryl monolaurate, triglyceryl monomyristate, triglyceryl monooleate, triglyceryl monostearate, etc.; tetraglycerol fatty acid esters such as tetraglyceryl monostearate, tetraglyceryl monooleate, etc.; pentaglycerol fats such as pentaglyceryl trimyristate, pentaglyceryl trioleate, pentaglyceryl monolaurate, pentaglyceryl monomyristate, pentaglyceryl monooleate, pentaglyceryl monostearate, etc. Examples of fatty acid esters include hexaglycerin fatty acid esters such as hexaglyceryl monooleate, hexaglyceryl monostearate, hexaglyceryl tristearate, hexaglyceryl monolaurate, and hexaglyceryl monomyristate, and decaglycerin fatty acid esters such as decaglyceryl monostearate, decaglyceryl distearate, decaglyceryl diisostearate, decaglyceryl dioleate, decaglyceryl tristearate, decaglyceryl trioleate, decaglyceryl monolaurate, decaglyceryl monomyristate, decaglyceryl monooleate, and decaglyceryl distearate; polyglycerin fatty acid esters such as lauryl glucoside; alkyl glucosides such as lauryl glucoside; fatty acid alkylol amides such as coconut oil fatty acid N-methylethanolamide and coconut oil fatty acid diethanolamide; and alkyl dimethylamine oxide solutions such as lauryl dimethylamine oxide solutions.

[0094] Examples of amphoteric surfactants include alkyl betaines such as lauryl dimethylaminoacetic acid betaine (lauryl betaine), stearyl betaine, lauric acid amidopropyl betaine, lauryl hydroxysulfobetaine, stearyl dimethylaminoacetic acid betaine, dodecyl aminomethyl dimethyl sulfopropyl betaine, and octadecyl aminomethyl dimethyl sulfopropyl betaine, and fatty acid amidopropyl betaines such as coconut acid amidopropyl betaine, coconut oil fatty acid amidopropyl dimethylaminoacetic acid betaine (cocamidopropyl betaine), and cocamidopropyl hydroxysultaine; alkyl imidazole types such as 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine; amine oxide types such as lauryl dimethylamine N-oxide, oleyl dimethylamine N-oxide, and lauramine oxide; and lecithins such as egg yolk lecithin, soybean lecithin, hydroxylated lecithin, and hydrogenated lecithin.

[0095] The emulsifier is preferably one or more selected from the group consisting of nonionic surfactants and amphoteric surfactants. The nonionic surfactant is more preferably one or more selected from the group consisting of polyglycerin fatty acid esters, glycerin fatty acid esters, and sorbitan fatty acid esters, and is also preferably one or more selected from the group consisting of polyglycerin fatty acid esters and glycerin fatty acid esters, one or more selected from the group consisting of polyglycerin fatty acid esters and sorbitan fatty acid esters, or one or more selected from the group consisting of glycerin fatty acid esters and sorbitan fatty acid esters. The amphoteric surfactant is more preferably lecithin. The lecithin may be hydrogenated (hydrogenated lecithin).

[0096] The degree of polymerization of the polyglycerol fatty acid ester is preferably 8 or more, more preferably 9 or more, while the degree of polymerization of the polyglycerol fatty acid ester is preferably 12 or less, more preferably 11 or less. Specific examples of the degree of polymerization of the polyglycerol fatty acid ester are 8 to 12 or 9 to 11. The fatty acid of the polyglycerol fatty acid ester may be a saturated fatty acid or an unsaturated fatty acid, and may be branched or linear. The number of carbon atoms of the fatty acid of the polyglycerol fatty acid ester is preferably 12 or more, more preferably 14 or more, even more preferably 16 or more, and even more preferably 17 or more, while the number of carbon atoms of the fatty acid of the polyglycerol fatty acid ester is preferably 20 or less, more preferably 19 or less. Specific examples of the number of carbon atoms of the fatty acid of the polyglycerol fatty acid ester are 12 to 20, 14 to 19, 16 to 20, or 17 to 19.

[0097] The fatty acid of the glycerin fatty acid ester may be saturated or unsaturated, and may be branched or linear. The number of carbon atoms of the fatty acid of the glycerin fatty acid ester is preferably 16 or more, more preferably 17 or more, while the number of carbon atoms of the fatty acid of the glycerin fatty acid ester is preferably 20 or less, more preferably 19 or less. The number of carbon atoms of the fatty acid of the glycerin fatty acid ester is specifically, for example, 16 to 20 or 17 to 19.

[0098] The fatty acid of the sorbitan fatty acid ester may be saturated or unsaturated, and may be branched or linear. The number of carbon atoms of the fatty acid of the sorbitan fatty acid ester is preferably 15 or more, more preferably 16 or more, while the number of carbon atoms of the fatty acid of the sorbitan fatty acid ester is preferably 19 or less, more preferably 18 or less. The number of carbon atoms of the fatty acid of the sorbitan fatty acid ester is specifically, for example, 15 to 19 or 16 to 18.

[0099] The content of the emulsifier relative to the total amount of the composition of the present disclosure is not particularly limited, but is preferably 0.5 wt% or more, more preferably 1.0 wt% or more, even more preferably 1.5 wt% or more, even more preferably 2.0 wt% or more, even more preferably 2.5 wt% or more, even more preferably 3.0 wt% or more, and even more preferably 3.5 wt% or more. On the other hand, the content of the emulsifier relative to the total amount of the composition is preferably 15.0 wt% or less, more preferably 13.0 wt% or less, even more preferably 10.0 wt% or less, even more preferably 7.0 wt% or less, even more preferably 5.0 wt% or less, and even more preferably 4.5 wt% or less. The content of the emulsifier relative to the total amount of the composition may be, specifically, for example, 0.5 wt % to 15.0 wt %, 1.0 wt % to 13.0 wt %, 1.5 wt % to 10.0 wt %, 2.0 wt % to 7.0 wt %, 2.5 wt % to 5.0 wt %, 3.0 wt % to 4.5 wt %, or 3.5 wt % to 4.5 wt %.

[0100] The composition of the present disclosure can be produced by a conventional method. Specifically, the composition of the present disclosure is not particularly limited, but can be produced, for example, by the following method. First, an oil phase is prepared by mixing and dissolving an oily component, and, if necessary, an emulsifier and optional components, under heating. Separately, an aqueous phase is prepared by mixing and dissolving a polyaspartic acid derivative, water, and, if necessary, an emulsifier and optional components, under heating. Next, the oil phase is gradually added to the prepared aqueous phase while stirring at 70°C to 85°C, and then emulsified by stirring and mixing at 4000 rpm to 8000 rpm for 30 seconds to 5 minutes using a known stirring device such as a homomixer, while heating if necessary. This allows the composition of the present disclosure to be produced.

[0101] The composition of the present disclosure, particularly in the form of a cream or emulsion, has a texture that quickly disintegrates as if melting when applied to the skin with the fingers, providing an excellent feel when used. Therefore, the composition of the present disclosure is suitable for use as an external preparation for skin, and specifically suitable for use as a cosmetic, quasi-drug, or pharmaceutical.

[0102] The use of the composition of the present disclosure is not particularly limited. The composition of the present disclosure can be suitably used, for example, in cleansing, emulsion, lotion, serum, makeup base, hair care, foundation, sunscreen, shaving cream, facial cleanser, facial cleanser, etc.

[0103] When applied as a skin external preparation, the dosage form may be any of the commonly known lotion, emulsion, essence, cream, powder-containing dosage forms, etc., with the cream or emulsion dosage form being particularly preferred.

[0104] [Optional Components] The composition of the present disclosure may optionally contain other components to the extent that the effects of the present disclosure are not significantly impaired. Such optional components include those commonly used in skin care products such as cosmetics, quasi-drugs, and pharmaceuticals. Examples of such optional components include the following:

[0105] Known thickeners include guar gum, quince seed, carrageenan, galactan, gum arabic, pectin, mannan, starch, xanthan gum, curdlan, methylcellulose, hydroxyethyl cellulose, carboxymethyl cellulose, methylhydroxypropyl cellulose, chondroitin sulfate, dermatan sulfate, glycogen, heparan sulfate, hyaluronic acid, sodium hyaluronate, tragacanth gum, keratan sulfate, chondroitin, mucoitin sulfate, hydroxyethyl guar gum, carboxymethyl guar gum, dextran, keratosulfuric acid, locust bean gum, succinoglucan, caronic acid, chitin, chitosan, carboxymethyl chitin, agar, polyvinyl alcohol, polyvinylpyrrolidone, carboxyvinyl polymer, alkyl-modified carboxyvinyl polymer, sodium polyacrylate, polyethylene glycol, and bentonite.

[0106] Examples of powders include powders such as mica, talc, kaolin, synthetic mica, calcium carbonate, magnesium carbonate, anhydrous silicic acid (silica), aluminum oxide, and barium sulfate, which may be surface-treated; inorganic pigments such as red iron oxide, yellow iron oxide, black iron oxide, cobalt oxide, ultramarine, iron blue, titanium oxide, and zinc oxide, which may be surface-treated; pearling agents such as titanium dioxide, fish phosphate foil, and bismuth oxychloride, which may be surface-treated; Examples of organic pigments include Red No. 202, Red No. 228, Red No. 226, Yellow No. 4, Blue No. 404, Yellow No. 5, Red No. 505, Red No. 230, Red No. 223, Orange No. 201, Red No. 213, Yellow No. 204, Yellow No. 203, Blue No. 1, Green No. 201, Purple No. 201, and Red No. 204, which may be methylated; and organic powders such as polyethylene powder, polymethyl methacrylate, nylon powder, and organopolysiloxane elastomer.

[0107] Examples of the ultraviolet absorber include para-aminobenzoic acid-based ultraviolet absorbers, anthranilic acid-based ultraviolet absorbers, salicylic acid-based ultraviolet absorbers, cinnamic acid-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, sugar-based ultraviolet absorbers, 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole, and 4-methoxy-4'-t-butyldibenzoylmethane.

[0108] Other optional ingredients include alcohols (e.g., lower alcohols such as methanol, ethanol, and propanol; polyhydric alcohols such as glycerin, propylene glycol, butylene glycol, and dipropylene glycol), fragrances, preservatives (e.g., phenoxyethanol), antibacterial agents (e.g., ethylhexylglycerin and glyceryl caprylate), pH adjusters, and colorants.

[0109] The initial viscosity of the composition of the present disclosure is not particularly limited and can be adjusted appropriately depending on the purpose, but is preferably 2,000 mPa·s or more, more preferably 5,000 mPa·s or more, even more preferably 10,000 mPa·s or more, even more preferably 20,000 mPa·s or more, even more preferably 25,000 mPa·s or more, even more preferably 30,000 mPa·s or more, and even more preferably 40,000 mPa·s or more. On the other hand, the initial viscosity of the composition of the present disclosure is preferably 70,000 mPa·s or less, more preferably 60,000 Pa·s or less, even more preferably 55,000 mPa·s or less, and even more preferably 50,000 mPa·s or less. Specifically, the initial viscosity of the composition of the present disclosure is, for example, 2,000 mPa·s to 70,000 mPa·s, 5,000 mPa·s to 60,000 mPa·s, 10,000 mPa·s to 55,000 mPa·s, 20,000 mPa·s to 70,000 mPa·s, 25,000 mPa·s to 60,000 mPa·s, 30,000 mPa·s to 55,000 mPa·s, or 40,000 mPa·s to 50,000 mPa·s. The initial viscosity of the composition of the present disclosure can be adjusted by, for example, the content of the polyaspartic acid derivative or the like in the composition of the present disclosure. In this disclosure, "initial viscosity" refers to the viscosity of the composition of the present disclosure immediately after preparation. The initial viscosity of the composition of the present disclosure is a measurement value obtained 30 seconds after the start of measurement using a digital Brookfield viscometer ("Digital Viscometer DV2T", manufactured by Eiko Instruments Co., Ltd.) with an LV-4 rotor, at a rotation speed of 6 rpm and a measurement temperature of 25°C.

[0110] The viscosity of the composition of the present disclosure after storage is not particularly limited, but is preferably 2,000 mPa·s or more, more preferably 5,000 mPa·s or more, even more preferably 10,000 mPa·s or more, even more preferably 18,000 mPa·s or more, even more preferably 20,000 mPa·s or more, even more preferably 25,000 mPa·s or more, even more preferably 30,000 mPa·s or more, and even more preferably 35,000 mPa·s or more. On the other hand, the viscosity of the composition of the present disclosure after storage is preferably 70,000 mPa·s or less, more preferably 60,000 Pa·s or less, even more preferably 55,000 mPa·s or less, even more preferably 50,000 mPa·s or less, and even more preferably 40,000 mPa·s or less. Specifically, the viscosity of the composition of the present disclosure after storage is, for example, 2,000 mPa·s to 70,000 mPa·s, 5,000 mPa·s to 60,000 mPa·s, 10,000 mPa·s to 55,000 mPa·s, 18,000 mPa·s to 70,000 mPa·s, 20,000 mPa·s to 60,000 mPa·s, 25,000 mPa·s to 55,000 mPa·s, 30,000 mPa·s to 50,000 mPa·s, or 35,000 mPa·s to 40,000 mPa·s. The viscosity after storage can be adjusted by, for example, the content of the polyaspartic acid derivative or the like in the composition of the present disclosure. In the present disclosure, the term "viscosity after storage" refers to the viscosity of the composition of the present disclosure after it has been left to stand for one month at 50° C. The viscosity of the composition of the present disclosure after storage is a measurement value taken 30 seconds after the start of measurement using a digital B-type viscometer ("Digital Viscometer DV2T", manufactured by Eiko Instruments Co., Ltd.) with an LV-4 rotor at a rotation speed of 6 rpm and a measurement temperature of 25° C.

[0111] The viscosity retention of the composition of the present disclosure is not particularly limited, but is preferably 70% or more, more preferably 75% or more, even more preferably 80% or more, even more preferably 85% or more, even more preferably 90% or more, and even more preferably 95% or more. On the other hand, the viscosity retention of the composition of the present disclosure is preferably 120% or less, more preferably 100% or less. Specifically, the viscosity retention of the composition of the present disclosure is, for example, 70% to 120%, 70% to 100%, 75% to 100%, 80% to 100%, 85% to 100%, 90% to 100%, or 95% to 100%. The polyaspartic acid derivative can provide an oil-in-water emulsion composition with excellent viscosity stability. In the present disclosure, "viscosity retention" refers to the ratio (%) of the viscosity (mPa·s) after storage to the initial viscosity (mPa·s). The closer the viscosity retention rate is to 100%, the higher the viscosity stability of the composition.

[0112] The volume-average median diameter (d50) of the emulsified particles in the composition of the present disclosure is not particularly limited, but is preferably 25.0 μm or less, more preferably 20.0 μm or less, even more preferably 15.0 μm or less, even more preferably 10.0 μm or less, even more preferably 5.0 μm or less, and even more preferably 3.0 μm or less. On the other hand, the volume-average median diameter (d50) of the emulsified particles in the composition of the present disclosure is preferably 0.5 μm or more, more preferably 1.0 μm or more, even more preferably 1.2 μm or more, even more preferably 1.5 μm or more, and even more preferably 2.0 μm or more. Specifically, the volume-average median diameter (d50) of the emulsified particles in the composition of the present disclosure is, for example, 0.5 μm to 25.0 μm, 0.5 μm to 20.0 μm, 0.5 μm to 15.0 μm, 1.0 μm to 10.0 μm, 1.0 μm to 5.0 μm, 1.2 μm to 3.0 μm, 1.5 μm to 25.0 μm, or 2.0 μm to 20.0 μm. The number-average median diameter (d50) of the emulsified particles in the composition of the present disclosure is not particularly limited, but is preferably 2.0 μm or less, more preferably 1.5 μm or less, even more preferably 1.0 μm or less, even more preferably 0.7 μm or less, even more preferably 0.5 μm or less, and still more preferably 0.1 μm or less. On the other hand, the number-average median diameter (d50) of the emulsified particles in the composition of the present disclosure is preferably 0.0001 μm or more, more preferably 0.0005 μm or more, even more preferably 0.001 μm or more, even more preferably 0.002 μm or more, even more preferably 0.01 μm or more, and still more preferably 0.02 μm or more. Specifically, the number-average median diameter (d50) of the emulsified particles in the composition of the present disclosure is, for example, 0.0001 μm to 2.0 μm, 0.0001 μm to 1.5 μm, 0.0005 μm to 1.0 μm, 0.001 μm to 0.7 μm, 0.001 μm to 0.5 μm, 0.002 μm to 0.1 μm, 0.01 μm to 2.0 μm, or 0.02 μm to 0.7 μm.The volume-average median diameter of emulsified particles and the number-average median diameter of emulsified particles can be adjusted by the type and content of each component contained in the composition of the present disclosure, the emulsification conditions (stirring conditions) during production of the composition of the present disclosure, etc. In the present disclosure, the median diameter refers to the volume-average or number-average median diameter measured using a laser diffraction particle size distribution analyzer ("SALD-7000", manufactured by Shimadzu Corporation).

[0113] The present disclosure will be described in detail below with reference to examples, but the present disclosure is not limited thereto.

[0114] Reference Example 1 Polyaspartic acid derivative 1 was prepared according to the following procedure.

[0115] <Synthesis of polysuccinimide (PSI)> 160 parts of aspartic acid (manufactured by YIXING QIANCHENG BIO-ENGINEERING CO., LTD., 99.97% purity) 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 then vacuum dried at 80°C to obtain 115 parts of PSI having a weight-average molecular weight of 80,000.

[0116] Synthesis of Polyaspartic Acid Derivative 1: 10.0 g of PSI and 95.3 g of dimethylformamide (DMF) were placed in a reaction vessel and heated to 60°C until the PSI was completely dissolved. After the resulting PSI solution was cooled to 40°C, a mixture of 0.229 g (1.5 mol % relative to 1 succinimide unit) of 1,2-bis(2-aminoethoxy)ethane (AEE; crosslinking agent) and 2.06 g of DMF was added to the PSI solution and allowed to react for 7 hours. Next, 10.3 g (54 mol % relative to 1 succinimide unit) of Farmin 20D (amine A; a mixture of 1% decylamine, 96% dodecylamine, and 3% tetradecylamine; manufactured by Kao Corporation) was added to the reaction solution and allowed to react for 30 minutes. Furthermore, 3.45 g of 3-amino-1-propanol (amine B; 44.5 mol % relative to 1 succinimide unit) was added to the reaction solution, and the reaction was carried out for 7 hours while maintaining the temperature inside the reaction vessel at 60°C. The reaction vessel was then cooled to room temperature and allowed to stand overnight. Thereafter, the reaction solution was poured into 1,200 mL of ethyl acetate with stirring to precipitate the reactant, and the solid was recovered by filtration. The recovered solid was further washed in 600 mL of ethyl acetate with stirring, and the solid was recovered by filtration. The recovered solid was dried at 60°C under reduced pressure for 12 hours, yielding 22.0 g of polyaspartic acid derivative 1 having a weight-average molecular weight of 145,000.

[0117] (Measurement of Weight-Average Molecular Weights of PSI and Polyaspartic Acid Derivative 1) In measuring the weight-average molecular weight of PSI, the polystyrene equivalent value was determined by GPC (differential refractometer). For the measurement, a G1000HHR column (TSKgel (registered trademark), manufactured by Tosoh Corporation), a G4000HHR column (TSKgel (registered trademark), manufactured by Tosoh Corporation), or a GMHHR-H column (TSKgel (registered trademark), manufactured by Tosoh Corporation) was used. Dimethylformamide containing 10 mM lithium bromide was used as the eluent. The weight-average molecular weight of polyaspartic acid derivative 1 was also measured by the same method.

[0118] (Calculation of composition ratio and hydroxyl value of polyaspartic acid derivative 1) First, １ The composition ratio (molar ratio) of polyaspartic acid derivative 1 was calculated using H-NMR.１ H-NMR measurement conditions: 0.1 g of polyaspartic acid derivative 1 was dissolved in 0.6 mL of deuterated dimethyl sulfoxide to prepare a measurement sample, and measurement was performed using a JNM-ECZ400S (manufactured by JEOL Ltd.) under the following conditions: Observation frequency: 400 MHz Chemical shift reference: TMS (tetramethylsilane) (0 ppm) Pulse delay: 6.8 seconds Number of scans: 16 Pulse width: 45° (3.2 μs) Measurement temperature: 60°C

[0119] The composition ratio (mol %) of the polyaspartic acid derivative 1 was １ Using H-NMR spectra, the following formulas were used for calculation: Ratio of the content (mol%) of monomer unit A-U to the content (mol%) of monomer unit B-U (A-U) / (B-U)=(peak integral value of methyl group derived from amine A / 3) / (peak integral value of methylene group derived from amine B / 2) Ratio of the total content (mol%) of monomer unit A-U and monomer unit B-U to the content (mol%) of monomer unit C-U [(A-U)+(B-U)] / (C-U)=[(peak integral value of methyl group derived from amine A / 3)+(peak integral value of methylene group derived from amine B / 2)] / (peak integral value of methine group of succinimide monomer unit)

[0120] Next, the contents (mol%) of the monomer units A-U and B-U were calculated from the following formulas, and the hydroxyl value was calculated based on the calculated values. Content (mol%) of monomer unit A-U = (charged amount of amine A (mol%) / charged amount of PSI (mol%)) × 100 Content (mol%) of monomer unit B-U = (charged amount of amine B (mol%) / charged amount of PSI (mol%)) × 100 Hydroxyl value = (charged amount of B-U (mol%) / 100) × 56.11 × 1000 / [97 + molecular weight of crosslinking agent × (charged amount of crosslinking agent (mol%) / 100) + molecular weight of amine A × (charged amount of A-U (mol%) / 100) + molecular weight of amine B × (charged amount of B-U (mol%) / 100)] In the above formula, "charge amount (mol %) of amine A," "charge amount (mol %) of amine B," and "charge amount (mol %) of crosslinking agent" refer to the ratio of the charge amount (mol) of amine A, the charge amount (mol %) of amine B, and the charge amount (mol %) of crosslinking agent, respectively, to the charge amount (mol) of PSI. "Charge amount (mol) of PSI" refers to the value obtained by dividing the weight of the charge amount of PSI by the molecular weight of the repeating unit of PSI.

[0121] The (A-U) / (B-U) ratio calculated by the above method was 53 / 37, and [(A-U)+(B-U)] / (C-U) was 90 / 7. The hydroxyl value of polyaspartic acid derivative 1 was 107 mgKOH / g.

[0122] Reference Example 2 Synthesis of Polyaspartic Acid Derivative 2 21 g of polyaspartic acid derivative 2 having a weight-average molecular weight of 150,000 was obtained by the same procedure as in Reference Example 1, except that 10.7 g (54 mol % relative to 1 succinimide unit) of Farmin CS (coconut amine (a mixture of 7% octylamine, 7% decylamine, 51% dodecylamine, 19% tetradecylamine, 8% cetylamine, 2% stearylamine, and 6% oleylamine), manufactured by Kao Corporation) was used instead of Farmin 20D as amine A. The compositional ratio of polyaspartic acid derivative 2 was (A-U) / (B-U) 58 / 39, and [(A-U) + (B-U)] / (C-U) 97 / 2. The hydroxyl value of polyaspartic acid derivative 2 was 108 mg KOH / g. The weight average molecular weight, composition ratio, and hydroxyl value of the polyaspartic acid derivative 2 were calculated in the same manner as in Reference Example 1.

[0123] Reference Example 3 Synthesis of Polyaspartic Acid Derivative 3 3.0 g of PSI and 16.8 g of N-methyl-2-pyrrolidone (NMP) were placed in a reaction vessel and heated at 130°C for 2 hours to completely dissolve the PSI. The resulting PSI solution was cooled to 80°C, and 1.68 g of ethanol was added dropwise to the PSI solution over 30 minutes while stirring. The reaction vessel was then cooled to 40°C, and 0.447 g of a 10 wt % NMP solution of 1,2-bis(2-aminoethoxy)ethane (AEE; crosslinker) (0.0447 g of AEE; a mixture of 1.0 mol % per mole of succinimide units and 0.403 g of NMP) was added to the PSI solution, allowing the reaction to proceed for 6 hours. The reaction vessel was then cooled to room temperature and allowed to stand overnight. Next, 6.7 g of a 50 wt % ethanol solution of Farmin 20D (amine A; a mixture of 1% decylamine, 96% dodecylamine, and 3% tetradecylamine; manufactured by Kao Corporation) (3.35 g as tetradecylamine; 52.0 mol % relative to 1 succinimide unit) was added to the reaction solution, and the mixture was allowed to react at 40°C for 4 hours. Furthermore, 1.383 g of 3-amino-1-propanol (amine B; 61.0 mol % relative to 1 succinimide unit) was added to the reaction solution, and the mixture was allowed to react at 40°C for 4 hours. The reaction vessel was then cooled to room temperature and allowed to stand overnight. Thereafter, the reaction solution was poured into 300 g of ethyl acetate with stirring to precipitate the reactant, and the solid was recovered by filtration. The recovered solid was then washed in 150 g of ethyl acetate with stirring, and the solid was recovered by filtration. The recovered solid was dried at 60°C under reduced pressure for 12 hours to obtain 6.71 g of polyaspartic acid derivative 3 having a weight-average molecular weight of 332,000. The compositional ratio of polyaspartic acid derivative 3 was (A-U) / (B-U) 57 / 43 and [(A-U) + (B-U)] / (C-U) 94 / 6. The hydroxyl value of polyaspartic acid derivative 3 was 101 mgKOH / g. The weight-average molecular weight, compositional ratio, and hydroxyl value of polyaspartic acid derivative 3 were calculated using the same procedures as in Reference Example 1.

[0124] Examples 1 to 4, Comparative Examples 1 to 2 Compositions (creams) of Examples 1 to 4 and Comparative Examples 1 and 2 were prepared according to the following procedure. First, component A listed in Table 1 was heated to 80°C and mixed and dissolved. In a separate container, component B was heated to 80°C and mixed and dissolved. Next, component A was gradually added to component B while stirring at 70 to 80°C. The resulting mixture was then emulsified by stirring and mixing at 6,000 rpm for 1 minute using a homomixer. After emulsification, component C was added to the emulsion in Comparative Example 2, or component C was not added in Examples 1 to 4 and Comparative Example 1. The mixture was air-cooled to 40°C or below while stirring at 75 rpm using a paddle. Component D was then added to the cooled emulsion and mixed with stirring to obtain each composition (cream) with the composition shown in Table 1.

[0125]

[0126] Examples 5 to 7, Comparative Examples 3 to 5 The compositions (milky lotions) of Examples 5 to 7 and Comparative Examples 3 to 5 were prepared according to the following procedure. Components A, B, and C listed in Table 2 were each heated to 85°C in separate containers and dissolved uniformly. Components A and B were mixed uniformly, and the mixture was gradually added to component C while stirring at 75 to 85°C. The mixture was emulsified by stirring and mixing using a homomixer at 6,000 rpm for 5 minutes. The resulting emulsion was air-cooled to 40°C or below while stirring at 150 rpm using a paddle, yielding each of the compositions (milky lotions) shown in Table 2.

[0127]

[0128] <Measurement of Viscosity (Initial Viscosity)> The viscosity (initial viscosity) of each of the compositions obtained in the Examples and Comparative Examples was measured using a digital Brookfield viscometer ("Digital Viscometer DV2T", manufactured by Eiko Seiki Co., Ltd.) An LV-4 rotor was used, and measurements were performed at a rotation speed of 6 rpm and a measurement temperature of 25°C, with the measured value 30 seconds after the start of measurement being recorded as the viscosity.

[0129] <Measurement of Viscosity (Viscosity after Storage)> Each composition of the Examples and Comparative Examples was allowed to stand at 50°C for one month, and then the viscosity of each composition (viscosity after storage) was measured using the same procedure as in measuring the initial viscosity.

[0130] <Calculation of Viscosity Retention Rate> The ratio (%) of the viscosity (mPa·s) after storage to the initial viscosity (mPa·s) was calculated and used as the viscosity retention rate.

[0131] <Measurement of Median Diameter of Emulsified Particles> For each of the compositions obtained in Examples and Comparative Examples, the median diameter of the emulsified particles in volume average terms was determined using a laser diffraction particle size distribution analyzer ("SALD-7000", manufactured by Shimadzu Corporation).

[0132] <Evaluation of texture> Ten expert panelists applied each composition of the Examples and Comparative Examples to their faces and evaluated the texture of the composition as it quickly crumbled, as if melting, on the skin, according to the following criteria. A rating of C or higher was considered good. A: Eight or more out of ten panelists answered that it felt like the composition crumbled on the skin. B: Five to eight out of ten panelists answered that it felt like the composition crumbled on the skin. C: Three to five out of ten panelists answered that it felt like the composition crumbled on the skin. D: Less than three out of ten panelists answered that it felt like the composition crumbled on the skin.

[0133] The results are shown in Tables 1 and 2. When the polyaspartic acid derivative was not contained (Comparative Examples 1 to 5), at least the initial viscosity was low or the median diameter of the emulsified particles was large, but when the polyaspartic acid derivative was contained (Examples 1 to 7), oil-in-water emulsion compositions were obtained that had a high initial viscosity and a small median diameter of the emulsified particles.

Claims

1. An oil-in-water emulsion composition comprising a polyaspartic acid derivative and an oily component, wherein the polyaspartic acid derivative comprises α- or β-aspartic acid monomer units A-U represented by the following general formula (1) and α- or β-aspartic acid monomer units B-U represented by the following general formula (2), and wherein the ratio (A-U) / (B-U) of the content (mol %) of the monomer units A-U to the content (mol %) of the monomer units B-U in the polyaspartic acid derivative is 40 / 60 to 60 / 40. (In the formula, R １ represents a hydrocarbon group having 3 to 22 carbon atoms. (In the formula, R ２ represents a hydrocarbon group containing a heteroatom and having 1 to 20 carbon atoms.

2. The oil-in-water emulsion composition according to claim 1, wherein the polyaspartic acid derivative further comprises succinimide monomer units C-U represented by the following formula (3), and the ratio of the total content (mol %) of the monomer units A-U and B-U to the content (mol %) of the monomer units C-U in the polyaspartic acid derivative, [(A-U) + (B-U)] / (C-U), is 80 / 20 to 99 / 1:

3. The oil-in-water emulsion composition according to claim 1 or 2, wherein the polyaspartic acid derivative further comprises an α- or β-aspartic acid monomer unit Crosslink-U represented by the following formula (4): (In the formula, the wavy lines indicate crosslinking sites.) 4. The oil-in-water emulsion composition according to claim 3, wherein the content of the Crosslink-U monomer unit in the polyaspartic acid derivative is 0.1 mol % to 2.0 mol %.

5. The oil-in-water emulsion composition according to claim 1 or 2, wherein the hydroxyl value of the polyaspartic acid derivative is 80 mg KOH / g to 170 mg KOH / g.

6. The oil-in-water emulsion composition according to claim 1 or 2, wherein the content of said polyaspartic acid derivative is 0.1 to 2.0% by weight based on the total amount of said oil-in-water emulsion composition.

7. The oil-in-water emulsion composition according to claim 1 or 2, further comprising an emulsifier.

8. The oil-in-water emulsion composition according to claim 7, wherein the content of said emulsifier relative to the total amount of said oil-in-water emulsion composition is 0.5% by weight to 15.0% by weight.

9. The oil-in-water emulsion composition according to claim 7, wherein the emulsifier is one or more selected from the group consisting of nonionic surfactants and amphoteric surfactants.

10. The oil-in-water emulsion composition according to claim 9, wherein the nonionic surfactant is one or more selected from the group consisting of polyglycerin fatty acid esters, glycerin fatty acid esters, and sorbitan fatty acid esters.

11. The oil-in-water emulsion composition according to claim 9, wherein the amphoteric surfactant is optionally hydrogenated lecithin.

12. The oil-in-water emulsion composition according to claim 1 or 2, wherein the content of the oily component relative to the total amount of the oil-in-water emulsion composition is 1.0% by weight to 50.0% by weight.

13. The oil-in-water emulsion composition according to claim 1 or 2, which is a topical skin preparation.

14. The oil-in-water emulsion composition according to claim 13, which is a cosmetic.

15. The oil-in-water emulsion composition according to claim 13, which is a cream or emulsion.

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