Method for producing polyaspartic acid derivative

Abstract

To provide a method for producing a polyaspartic acid derivative using a reduced amount of solvent in purification.SOLUTION: A method for producing a polyaspartic acid derivative, comprises at least one step selected from the group consisting of: step (a) of modifying a polymer containing a monomer unit derived from succinimide with a specific amine in the presence of a solvent a; step (b) of modifying a polymer containing a monomer unit derived from succinimide with a specific amine in the presence of a solvent b; and step (c) of crosslinking a polymer containing a monomer unit derived from succinimide with a crosslinking agent in the presence of a solvent c; and a step (d) of subsequently drying a reaction solution with a drum dryer. The solvents a to c contain at least one selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing a polyaspartic acid derivative. [Background technology]

[0002] Polyacrylic acid polymers, such as carboxyvinyl polymers, have been used as thickeners for cosmetics and water-absorbent polymers for hygiene products. However, because polyacrylic acid polymers are derived from petroleum and are non-biodegradable, there is a growing demand for alternatives to polyacrylic acid polymers from an environmental perspective.

[0003] Polyaspartic acid derivatives are known as alternative polymers. Polyaspartic acid derivatives are made from polysuccinimide, which is obtained by, for example, thermal condensation of bio-derived aspartic acid. A known method for producing polyaspartic acid derivatives involves reacting polysuccinimide dissolved in a reaction solvent such as dimethylformamide with an amine such as n-dodecylamine or hydroxypropylamine. To purify the polyaspartic acid derivative from the resulting reaction solution, a known method (reprecipitation method) involves stirring the reaction solution in a large amount of a poor solvent (acetonitrile) to precipitate the polyaspartic acid derivative, which is then filtered to obtain the polyaspartic acid derivative (Patent Document 1). However, since a large amount of solvent is required for reprecipitation, improvements have been required from the viewpoints of cost and the environment. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-344061 Summary of the Invention [Problem to be solved by the invention]

[0005] Furthermore, a small amount of the reaction solvent remains in the solid separated by filtration after reprecipitation, which makes the solid sticky, necessitating further washing with a poor solvent. Furthermore, due to this stickiness, the filtration before washing is also time-consuming. Furthermore, since the polyaspartic acid derivative obtained by reprecipitation is in the form of very fine particles, it absorbs a large amount of the poor solvent, and therefore requires prolonged drying to remove the poor solvent.

[0006] Therefore, an object of the present disclosure is to provide a method for producing a polyaspartic acid derivative in which a small amount of solvent is used in purifying the polyaspartic acid derivative. [Means for solving the problem]

[0007] As a result of intensive research to solve the above problems, the inventors discovered that the amount of solvent used in purification can be reduced by drying the reaction solution of a polyaspartic acid derivative using a drum dryer, and thus completed the invention of the present disclosure.

[0008] That is, the invention of the present disclosure is as follows. [1] One or more steps selected from the group consisting of the following steps (a), (b), and (c): and a method for producing a polyaspartic acid derivative, comprising step (d) after one or more steps selected from the group consisting of steps (a), (b), and (c). Step (a): A step of modifying a polymer containing a monomer unit derived from succinimide with an amine represented by the following general formula (1) in the presence of a solvent a, the solvent a contains one or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone; R1-NH2(1) (In the formula, R1 represents a group containing a hydrocarbon group having 3 to 22 carbon atoms which may contain a heteroatom.) Step (b): A step of modifying a polymer containing a monomer unit derived from succinimide with one or more amines selected from the group consisting of amines represented by the following general formula (2) and amines represented by the following general formula (3) in the presence of a solvent b, the solvent b contains one or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone; OH-R2-NH2(2) (In the formula, R2 represents a group containing a hydrocarbon group having 1 to 16 carbon atoms which may contain a heteroatom.) OH-R3-NH-R4(3) (In the formula, R3 represents a group containing a hydrocarbon group having 1 to 8 carbon atoms which may contain a heteroatom, and R4 represents a group containing a hydrocarbon group having 1 to 8 carbon atoms which may contain a heteroatom.) Step (c): A step of crosslinking a polymer containing a monomer unit derived from succinimide with a crosslinking agent in the presence of a solvent c, the solvent c contains one or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone; Step (d): A step of drying the obtained reaction liquid with a drum dryer [2] The production method according to [1], wherein the temperature of the drum surface of the drum dryer in step (d) is at least 5°C higher than the temperature at which the solvent in the reaction solution evaporates according to the equilibrium vapor pressure curve of the solvent under the vapor internal pressure conditions of the drum dryer in step (d). [3] The production method according to [1] or [2], wherein the internal steam pressure of the drum dryer in the step (d) is 0.1 kPa to 50 kPa. [4] The method according to any one of [1] to [3], wherein the temperature of the drum surface of the drum dryer in the step (d) is 20°C to 200°C. [Effects of the Invention]

[0009] According to the invention of the present disclosure, the amount of solvent used for purification can be reduced by drying the reaction solution of the polyaspartic acid derivative with a drum dryer.

[0010] Furthermore, according to the invention of the present disclosure, a fibrous polyaspartic acid derivative having almost no tackiness can be obtained, making it easy to handle. Furthermore, according to the present invention, when the obtained polyaspartic acid derivative is washed with a poor solvent for further purification, the amount of poor solvent absorbed by the polyaspartic acid derivative is reduced, and the weight and volume of the polyaspartic acid derivative slurry are reduced, making it easier to handle. Furthermore, when the slurry is subsequently dried, the drying time required to remove the poor solvent is also shortened. In particular, when the production method of the present disclosure includes one or more steps selected from step (a) and step (b), the invention of the present disclosure can reduce the amount of unreacted amine (free amine) remaining in the polyaspartic acid derivative after the step. This reduces the amount of acid required for pH adjustment when the polyaspartic acid derivative is used for a desired purpose, such as cosmetics. Furthermore, while the viscosity of polyaspartic acid derivatives tends to decrease when exposed to acid, the amount of acid used for pH adjustment can be reduced, making it easier to maintain a high viscosity in compositions containing the polyaspartic acid derivative. [Brief explanation of the drawings]

[0011] [Figure 1] 1 shows the equilibrium vapor pressure curves of dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and N-methylpyrrolidone (NMP). DETAILED DESCRIPTION OF THE INVENTION

[0012] The present disclosure will be described in more detail below. Note that the present disclosure is not limited to the following embodiments.

[0013] The expressions "XX or more and YY or less" or "XX to YY" that represent a numerical range mean a numerical range including the endpoints, that is, the lower limit and the upper limit, unless otherwise specified. When numerical ranges are stated in stages, the upper and lower limits of each numerical range can be combined in any way.

[0014] <First Aspect> A first aspect of the present disclosure is a method for producing a polyaspartic acid derivative (also referred to as the "production method of the present disclosure"), which includes one or more steps selected from the group consisting of steps (a), (b), and (c) below, and step (d) after one or more steps selected from the group consisting of steps (a), (b), and (c): Step (a): A step of modifying a polymer containing a monomer unit derived from succinimide with an amine represented by the following general formula (1) in the presence of a solvent a, The solvent a contains one or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone. R1-NH2(1) (In the formula, R1 represents a group containing a hydrocarbon group having 3 to 22 carbon atoms which may contain a heteroatom.) Step (b): A step of modifying a polymer containing a monomer unit derived from succinimide with one or more amines selected from the group consisting of amines represented by the following general formula (2) and amines represented by the following general formula (3) in the presence of a solvent b, The solvent b contains one or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone. OH-R2-NH2(2) (In the formula, R2 represents a group containing a hydrocarbon group having 1 to 16 carbon atoms which may contain a heteroatom.) OH-R3-NH-R4(3) (In the formula, R3 represents a group containing a hydrocarbon group having 1 to 8 carbon atoms which may contain a heteroatom, and R4 represents a group containing a hydrocarbon group having 1 to 8 carbon atoms which may contain a heteroatom.) Step (c): A step of crosslinking a polymer containing a monomer unit derived from succinimide with a crosslinking agent in the presence of a solvent c, Step c, wherein the solvent c contains one or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone. Step (d): A step of drying the obtained reaction liquid with a drum dryer.

[0015] [Polymer containing succinimide-derived monomer units] The "polymer containing a monomer unit derived from succinimide" (also referred to as "polymer") in steps (a), (b), and (c) is a polymer containing a monomer unit represented by the following formula (4) (also referred to as "monomer unit CU").

[0016] [ka]

[0017] An example of a polymer containing a monomer unit derived from succinimide is polysuccinimide (also referred to as "PSI"). Polysuccinimide is a polymer formed by polymerizing a monomer unit represented by the above formula (4). The degree of polymerization of the monomer unit represented by the above formula (4) in polysuccinimide is not particularly limited, but is, for example, 10 to 10,000.

[0018] Polysuccinimide can be produced by known methods, for example, by heating aspartic acid in the presence of phosphoric acid at 170 to 190°C in a vacuum to cause dehydration condensation. To obtain 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, but may be, for example, a weight-average molecular weight of 20,000 or more, 50,000 or more, or 70,000 or more, or 500,000 or less, 200,000 or less, or 100,000 or less. Specifically, the weight-average molecular weight may be, for example, 20,000 to 500,000, 50,000 to 200,000, or 70,000 to 100,000. In the present disclosure, the weight-average molecular weight refers to a converted value measured by the GPC method (differential refractometer) using polystyrene as a standard substance, and specifically refers to the 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.

[0019] The amount of the succinimide-derived monomer units present in the constituent monomers of a polymer containing the succinimide-derived monomer units is not particularly limited, and may be, for example, 40 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, or 95 mol% or more, or 100 mol% or less, 98 mol% or less, 95 mol% or less, 90 mol% or less, 80 mol% or less, 70 mol% or less, 60 mol% or less, or 50 mol% or less, or any compatible combination thereof. Specifically, it may be, for example, 40 mol% to 100 mol%, 50 mol% to 98 mol%, 60 mol% to 95 mol%, 70 mol% to 90 mol%, 80 mol% to 95 mol%, 90 mol% to 98 mol%, 95 mol% to 100 mol%, 70 mol% to 80 mol%, 60 mol% to 70 mol% or less, 50 mol% to 60 mol%, or 40 mol% to 50 mol%.

[0020] The polymer containing a monomer unit derived from succinimide may contain a monomer unit other than the monomer unit derived from succinimide. For example, the polymer containing a monomer unit derived from succinimide may contain a part of the monomer unit containing one or more amines selected from the group consisting of amine A and amine B. The amine A and the amine B will be described later. In other words, the polymer containing a monomer unit derived from succinimide may further contain one or more selected from the group consisting of an α- or β-polyaspartic acid monomer unit AU (also referred to as a "monomer unit AU") represented by the following general formula (5), an α- or β-polyaspartic acid monomer unit B'-U represented by the following general formula (6), and an α- or β-polyaspartic acid monomer unit B"-U represented by the following general formula (7). Note that one or more selected from the group consisting of an α- or β-polyaspartic acid monomer unit B'-U represented by the general formula (6) and an α- or β-polyaspartic acid monomer unit B"-U represented by the general formula (7) are also collectively referred to as a "monomer unit BU".

[0021] [ka] (In the formula, R1 represents a group containing a hydrocarbon group having 3 to 22 carbon atoms which may contain a heteroatom.)

[0022] With respect to R1 in general formula (5), the explanation given below regarding R1 in general formula (1) is incorporated herein by reference.

[0023] [ka] (wherein R2 is a hydrocarbon group containing 1 to 16 carbon atoms which may contain a heteroatom) )

[0024] [ka] (In the formula, R3 represents a group containing a hydrocarbon group having 1 to 8 carbon atoms which may contain a heteroatom, and R4 represents a group containing a hydrocarbon group having 1 to 8 carbon atoms which may contain a heteroatom.)

[0025] The explanation for R2 in general formula (6) is incorporated herein by reference, and the explanation for R3 in general formula (2) is incorporated herein by reference, while the explanation for R3 and R4 in general formula (3) is incorporated herein by reference.

[0026] The monomer unit AU may be one resulting from the modification in step (a). Furthermore, the monomer unit BU may be one resulting from the modification in step (b), which will be described later. For example, when the production method of the present disclosure includes steps (a) and (b), and step (b) is performed before step (a), the polymer containing succinimide-derived monomer units and subjected to step (a) may be partially modified with amine B. For example, when the production method of the present disclosure includes steps (a) and (b), and step (b) is performed after step (a), the polymer containing succinimide-derived monomer units and subjected to step (b) may be partially modified with amine A. For example, when the production method of the present disclosure includes steps (a) and (c), and step (a) is performed before step (c), the polymer containing succinimide-derived monomer units and subjected to step (c) may be partially modified with amine A. Furthermore, for example, when the production method of the present disclosure includes step (b) and step (c), and step (b) is performed before step (c), the polymer containing a succinimide-derived monomer unit to be subjected to step (c) may be partially modified with amine B.

[0027] The polymer containing the succinimide-derived monomer unit may have a crosslinked structure. In other words, the polymer containing the succinimide-derived monomer unit may further contain an α- or β-polyaspartic acid monomer unit Crosslink-U (also referred to as "monomer unit Crosslink-U") represented by the following general formula (8):

[0028] [ka] (In the formula, the wavy lines indicate crosslinking sites.)

[0029] The crosslinked structure may be formed, for example, by step (c). For example, when the production method of the present disclosure includes steps (a) and (c), and step (c) is performed before step (a), the polymer containing a monomer unit derived from succinimide and subjected to step (a) may have a crosslinked structure. Furthermore, when the production method of the present disclosure includes steps (b) and (c), and step (c) is performed before step (b), the polymer containing a monomer unit derived from succinimide and subjected to step (b) may have a crosslinked structure.

[0030] The polymer containing a monomer unit derived from succinimide may be a polymer containing a monomer unit derived from succinimide and one or more selected from the group consisting of a monomer unit AU, a monomer unit B'-U, a monomer unit B"-U, and a monomer unit Crosslink-U. Furthermore, the polymer containing a monomer unit derived from succinimide may be a polymer consisting of a monomer unit derived from succinimide and one or more selected from the group consisting of a monomer unit AU, a monomer unit B'-U, a monomer unit B"-U, and a monomer unit Crosslink-U.

[0031] [Step (a)] Step (a) is a step of modifying a polymer containing a monomer unit derived from succinimide with an amine represented by the following general formula (1) (also referred to as "amine A") in the presence of a solvent a. R1-NH2(1) (In the formula, R1 represents a group containing a hydrocarbon group having 3 to 22 carbon atoms which may contain a heteroatom.)

[0032] In step (a), the succinimide ring in the polymer is opened by amine A, and amine A is added to the succinimide-derived monomer unit. That is, in step (a), an addition reaction of amine A occurs, accompanied by cleavage of the succinimide ring.

[0033] In general formula (1), R1 is not particularly limited as long as it is a group containing a hydrocarbon group having 3 to 22 carbon atoms. R1 may be saturated or unsaturated, may be branched or linear, or may have a ring structure. 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. Among these, alkyl groups are preferred as hydrocarbon groups having 3 to 22 carbon atoms.

[0034] The number of carbon atoms in the hydrocarbon group having 3 to 22 carbon atoms in R1 is not particularly limited, and may be, for example, 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, 10 or more, or 11 or more, or may be 22 or less, 21 or less, 20 or less, 19 or less, 18 or less, 17 or less, 16 or less, 15 or less, or 14 or less. The number of carbon atoms in the hydrocarbon group having 3 to 22 carbon atoms in R1 may specifically be, 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.

[0035] Furthermore, the group containing a hydrocarbon group having 3 to 22 carbon atoms in R1 may contain a heteroatom. 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 group containing a hydrocarbon group having 3 to 22 carbon atoms and containing a heteroatom include the above-mentioned hydrocarbon group having 3 to 25 carbon atoms interposed by a heteroatom. Examples of the interposed heteroatom include one or more selected from the group consisting of -O-, -N-, and -S-.

[0036] Therefore, the amine A may be, for example, an amine represented by the following general formula (1′): R 11 -LR 12 -NH2(1') (In the formula, R 11 and R 12 each represents a hydrocarbon group having 1 to 21 carbon atoms, and R 11 and the number of carbon atoms in R 12 The sum of the number of carbon atoms in R is 3 to 22. 11 The number of carbon atoms in R is preferably 18 to 21. 12 The number of carbon atoms is preferably 1 to 4. L represents a nitrogen atom, an oxygen atom, or a sulfur atom.

[0037] R 11 and R 12 may be saturated or unsaturated, may be branched or straight, and may have a ring structure.

[0038] "R" in general formula (1') 11 -LR 12Specific examples of "-" include an ethoxymethylene group, a propoxymethylene group, a butoxymethylene group, a pentoxymethylene group, a hexanoxymethylene group, a heptanoxymethylene group, an octanoxymethylene group, a nonanoxymethylene group, a decanoxymethylene group, an undecanoxymethylene group, a dodecanoxymethylene group, a tridecanoxymethylene group, a tetradecanoxymethylene group, a pentadecanoxymethylene group, a hexadecanoxymethylene group, a heptadecanoxymethylene group, an octadecanoxymethylene group, a nonadecanoxymethylene group, an ethoxyethylene group, a propoxyethylene group, a butoxyethylene group, a pentoxyethylene group, a hexanoxyethylene group, group, heptanoxyethylene group, octanoxyethylene group, nonanoxyethylene group, decanoxyethylene group, undecanoxyethylene group, dodecanoxyethylene group, tridecanoxyethylene group, tetradecanoxyethylene group, pentadecanoxyethylene group, hexadecanoxyethylene group, heptadecanoxyethylene group, octadecanoxyethylene group, nonadecanoxyethylene group, ethoxypropylene group, propoxypropylene group, butoxypropylene group, pentoxypropylene group, hexanoxypropylene group, heptanoxypropylene group, octanoxypropylene group, nonanoxypropylene group, decanoxypropylene group, undecanoxypropylene group , dodecanoxypropylene group, tridecanoxypropylene group, tetradecanoxypropylene group, pentadecanoxypropylene group, hexadecanoxypropylene group, heptadecanoxypropylene group, octadecanoxypropylene group, nonadecanoxypropylene group, ethoxytetramethylene group, propoxytetramethylene group, butoxytetramethylene group, pentoxytetramethylene group, hexanoxytetramethylene group, heptanoxytetramethylene group alkyl alkylene groups such as a lamethylene group, an octanoxytetramethylene group, a nonanoxytetramethylene group, a decanoxytetramethylene group, an undecanoxytetramethylene group, a dodecanoxytetramethylene group, a tridecanooxytetramethylene group, a tetradecanoxytetramethylene group, a pentadecanooxytetramethylene group, a hexadecanoxytetramethylene group, a heptadecanooxytetramethylene group, and an octadecanooxytetramethylene group; Ethylthiomethyl group, propylthiomethyl group, butylthiomethyl group, pentylthiomethyl group, hexylthiomethyl group, heptylthiomethyl group, octylthiomethyl group, nonylthiomethyl group, decylthiomethyl group, undecylthiomethyl group, dodecylthiomethyl group, tridecylthiomethyl group, tetradecylthiomethyl group, pentadecylthiomethyl group, hexadecylthiomethyl group, heptadecylthiomethyl group, octadecylthiomethyl group, nonadecylthiomethyl group, ethylthiomethyl group thioethyl, propylthioethyl, butylthioethyl, pentylthioethyl, hexylthioethyl, heptylthioethyl, octylthioethyl, nonylthioethyl, decylthioethyl, undecylthioethyl, dodecylthioethyl, tridecylthioethyl, tetradecylthioethyl, pentadecylthioethyl, hexadecylthioethyl, heptadecylthioethyl, octadecylthioethyl, nonadecylthioethyl, ethylthiopropyl, pro and alkylthioalkyl groups such as ethylthiopropyl group, butylthiopropyl group, pentylthiopropyl group, hexylthiopropyl group, heptylthiopropyl group, octylthiopropyl group, nonylthiopropyl group, decylthiopropyl group, undecylthiopropyl group, dodecylthiopropyl group, tridecylthiopropyl group, tetradecylthiopropyl group, pentadecylthiopropyl group, hexadecylthiopropyl group, heptadecylthiopropyl group, octadecylthiopropyl group, nonadecylthiopropyl group, ethylthiobutyl group, propylthiobutyl group, butylthiobutyl group, pentylthiobutyl group, hexylthiobutyl group, heptylthiobutyl group, octylthiobutyl group, nonylthiobutyl group, decylthiobutyl group, undecylthiobutyl group, dodecylthiobutyl group, tridecylthiobutyl group, tetradecylthiobutyl group, pentadecylthiobutyl group, hexadecylthiobutyl group, heptadecylthiobutyl group, and octadecylthiobutyl group.

[0039] The amine A may be used alone or in combination of two or more.

[0040] The amount of amine A charged is not particularly limited, and may be, for example, 20 mol% or more, 25 mol% or more, or 30 mol% or more, or 60 mol% or less, 58 mol% or less, or 57 mol% or less, relative to the number of moles of monomer units derived from succinimide. Specifically, the amount of amine A charged may be, for example, 20 mol% to 60 mol%, 25 mol% to 58 mol%, or 30 mol% to 57 mol%. Furthermore, when step (a) is performed after step (b), the amount of amine A charged is preferably greater than the amount required for the reaction in order to promote the reaction in step (a). In the present disclosure, the "number of moles of monomer units derived from succinimide" can be calculated, for example, by dividing the weight of the charged amount of polysuccinimide by the molecular weight of succinimide.

[0041] Solvent a contains one or more selected from the group consisting of dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and N-methylpyrrolidone (NMP). One or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone act as a solvent for dissolving a polymer containing a monomer unit derived from succinimide. In particular, dimethyl sulfoxide and N-methylpyrrolidone are preferred because of their low toxicity. Therefore, it is preferable that the one or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone are one or more selected from the group consisting of dimethyl sulfoxide and N-methylpyrrolidone. One or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone may be used alone or in combination of two or more.

[0042] As long as the reaction in step (a) can proceed, the solvent a may further contain one or more solvents other than dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone. Specifically, the solvent a may further contain an aprotic polar organic solvent such as dimethylacetamide (DMAc), dimethylimidazolidinone (DMI), sulfolane, 3-methoxy-N,N-dimethylpropanamide, or 3-butoxy-N,N-dimethylpropanamide.

[0043] The content of one or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone in solvent a is not particularly limited as long as the reaction in step (a) can proceed, and may be, for example, 70% by weight or more, 80% by weight or more, 90% by weight or more, or 95% by weight or more, or 100% by weight or less, 95% by weight or less, 90% by weight or less, or 80% by weight or less, or any compatible combination thereof. The total content may be, for example, 70% by weight to 100% by weight, 80% by weight to 95% by weight, 90% by weight to 95% by weight, 95% by weight to 100% by weight, 80% by weight to 90% by weight, or 70% by weight to 80% by weight.

[0044] The concentration of the polymer containing a monomer unit derived from succinimide in solvent a is not particularly limited, and may be, for example, 1.0 wt % or more, 3.0 wt % or more, 5.0 wt % or more, 10.0 wt % or more, 15.0 wt % or more, or 20.0 wt % or more, or 50.0 wt % or less, 40.0 wt % or less, 30.0 wt % or less, 20.0 wt % or less, 15.0 wt % or less, or 10.0 wt % or less, or any compatible combination thereof. The concentration of the polymer containing a monomer unit derived from succinimide in solvent a may be, for example, 1.0 wt % to 50.0 wt %, 3.0 wt % to 40.0 wt %, 5.0 wt % to 30.0 wt %, 10.0 wt % to 20.0 wt %, 15.0 wt % to 50.0 wt %, 20.0 wt % to 40.0 wt %, 1.0 wt % to 15.0 wt %, or 3.0 wt % to 10.0 wt %.

[0045] Step (a) can be carried out by a known method. Specific procedures for step (a) include, for example, dissolving a polymer containing a succinimide-derived monomer unit in a solvent, adding dropwise a solvent solution containing amine A, and reacting the resulting mixture under a predetermined temperature condition.

[0046] The temperature conditions for step (a) are not particularly limited as long as the progress of the reaction can be substantially maintained. Step (a) may be carried out at a temperature of, for example, 5° C. or higher, 10° C. or higher, 15° C. or higher, 20° C. or higher, 25° C. or higher, 30° C. or higher, or 35° C. or higher, or at a temperature of 150° C. or lower, 140° C. or lower, 130° C. or lower, 120° C. or lower, 110° C. or lower, 100° C. or lower, 95° C. or lower, 90° C. or lower, 85° C. or lower, 80° C. or lower, 75° C. or lower, 70° C. or lower, 65° C. or lower, or 60° C. or lower. Step (a) may be carried out at a temperature of, for example, 5°C to 150°C, 10°C to 140°C, 15°C to 130°C, 20°C to 120°C, 25°C to 110°C, 30°C to 100°C, 35°C to 95°C, 5°C to 90°C, 10°C to 85°C, 15°C to 80°C, 20°C to 75°C, 25°C to 70°C or less, 30°C to 65°C, or 35°C to 60°C.

[0047] The reaction time of step (a) is not particularly limited as long as the reaction of step (a) can proceed, but may be, for example, 5 minutes or more, 10 minutes or more, 20 minutes or more, 30 minutes or more, 40 minutes or more, 50 minutes or more, 1 hour or more, or The incubation time may be 1 hour or more, 2 hours or more, or 3 hours or more, or 10 hours or less, 5 hours or less, 4 hours or less, 3 hours or less, 2 hours or less, 1 hour or less, 50 minutes or less, 40 minutes or less, 30 minutes or less, 20 minutes or less, or 10 minutes or less, or any combination thereof that is not contradictory. Specifically, the incubation time may be, for example, 5 minutes to 10 hours, 10 minutes to 5 hours, 20 minutes to 4 hours, 30 minutes to 3 hours, 40 minutes to 2 hours, 50 minutes to 1 hour, 1 hour to 10 hours, 2 hours to 5 hours, 3 hours to 4 hours, 5 minutes to 50 minutes, 10 minutes to 40 minutes, 20 minutes to 30 minutes or less, 5 minutes to 20 minutes, or 5 minutes to 10 minutes.

[0048] The polyaspartic acid derivative obtained in step (a) may be a polymer containing succinimide-derived monomer units in which all of the succinimide-derived monomer units have been modified with amine A, or a polymer in which some of the succinimide-derived monomer units are unmodified.

[0049] [Step (b)] Step (b) is a step of modifying a polymer containing a succinimide-derived monomer unit with one or more amines selected from the group consisting of amines represented by the following general formula (2) and amines represented by the following general formula (3) (collectively referred to as "amine B") in the presence of solvent b: OH-R2-NH2(2) (In the formula, R2 represents a group containing a hydrocarbon group having 1 to 16 carbon atoms which may contain a heteroatom.) OH-R3-NH-R4(3) (In the formula, R3 represents a group containing a hydrocarbon group having 1 to 8 carbon atoms which may contain a heteroatom, and R4 represents a group containing a hydrocarbon group having 1 to 8 carbon atoms which may contain a heteroatom.)

[0050] In step (b), the succinimide ring in the polymer is opened by amine B, and amine B is added to the succinimide-derived monomer unit. That is, in step (b), an addition reaction of amine B occurs, accompanied by cleavage of the succinimide ring.

[0051] In general formula (2), R2 is not particularly limited as long as it is a group containing a hydrocarbon group having 1 to 16 carbon atoms. R2 may be saturated or unsaturated, branched or linear, or may have a ring structure. Specific examples of the hydrocarbon group having 1 to 16 carbon atoms include an ethylene group (-CH2CH2-), a trimethylene group (-CH2CH2CH2-), a tetramethylene group (-CH2CH2CH2CH2-), a pentamethylene group (-CH2CH2CH2CH2CH2-), a hexamethylene group (-CH2CH2CH2CH2CH2CH2-), a heptamethylene group (-CH2CH2CH2CH2CH2CH2-), a methyl ... Examples of alkylene groups include linear alkylene groups such as an octamethylene group (-CH(CH)CH-, -CHCH(CH)-) and an octamethylene group (-CHCHCHCHCHCHCHCHCH-); branched alkylene groups such as a propylene group (-CH(CH)CH-, -CHCH(CH)-) and a 1,2-dimethylethylene group (-(CH)CHCH(CH)-); and alkenyl groups such as a propenylene group (-CHCH=CH-, -CH=CHCH-). Among these, branched or straight chain alkylene groups are preferred, and straight chain alkylene groups are more preferred.

[0052] Furthermore, the group containing a hydrocarbon group having 1 to 16 carbon atoms in R2 may contain a heteroatom, such as one or more selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom. Examples of the group containing a hydrocarbon group having 1 to 16 carbon atoms and containing a hetero atom include the above-mentioned hydrocarbon groups having 1 to 16 carbon atoms in which one or more hydrogen atoms have been substituted with a substituent containing a hetero atom. Examples of the substituent containing a hetero atom include a hydroxy group (-OH), an alkyl group (-ALPHA ... and at least one selected from the group consisting of an amino group (-NH2), and a thiol group (-SH). Specific examples of hydrocarbon groups having 1 to 16 carbon atoms substituted with a heteroatom-containing substituent include hydroxyalkylene groups such as a hydroxyethylene group (-CH(OH)CH2-), a hydroxypropylene group (-CH2CH(OH)CH2-), and a hydroxybutylene group (-CH2CH2CH(OH)CH2-), and polyhydroxyalkylene groups such as a group obtained by removing the amino group (-NH2-) and the terminal hydroxy group (-OH) from D-glucamine.

[0053] The number of carbon atoms in the hydrocarbon group having 1 to 16 carbon atoms in R2 is not particularly limited, and may be, for example, 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, 10 or more, 11 or more, or 12 or more, or 16 or less, 15 or less, 14 or less, 13 or less, 12 or less, 11 or less, 10 or less, 9 or less, 8 or less, 7 or less, 6 or less, or 5 or less, or any compatible combination thereof. Specific examples of the number of carbon atoms in the hydrocarbon group having 1 to 16 carbon atoms in R2 may be 1 to 16, 2 to 15, 3 to 14, 4 to 13, 5 to 12, 6 to 11, 7 to 10, 8 to 9, 9 to 16, 10 to 15, 11 to 14, 12 to 13, 1 to 8, 2 to 7, 3 to 6, or 4 to 5.

[0054] In general formula (3), R3 is not particularly limited as long as it is a group containing a hydrocarbon group having 1 to 8 carbon atoms. R3 may be saturated or unsaturated, branched or linear, or may have a ring structure. Specific examples of the hydrocarbon group having 1 to 8 carbon atoms include an ethylene group (-CH2CH2-), a trimethylene group (-CH2CH2CH2-), a tetramethylene group (-CH2CH2CH2CH2-), a pentamethylene group (-CH2CH2CH2CH2CH2-), a hexamethylene group (-CH2CH2CH2CH2CH2CH2-), a heptamethylene group (-CH2CH2CH2CH2CH2CH2-), a methyl group (- ... 2CH2-), and octamethylene group (-CH2CH2CH2CH2CH2CH2CH2CH2-); branched alkylene groups such as propylene group (-CH(CH3)CH2-, -CH2CH(CH3)-), and 1,2-dimethylethylene group (-(CH3)CHCH(CH3)-); and alkenyl groups such as propenylene group (-CH2CH=CH-, -CH=CHCH2-). Among these, branched or straight chain alkylene groups are preferred, and straight chain alkylene groups are more preferred.

[0055] Furthermore, the group containing a hydrocarbon group having 1 to 8 carbon atoms in R3 may contain a heteroatom, such as one or more selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom. Examples of groups containing a hydrocarbon group having 1 to 8 carbon atoms and containing a heteroatom include those in which one or more hydrogen atoms of the above-mentioned hydrocarbon group having 1 to 8 carbon atoms are substituted with a substituent containing a heteroatom. Examples of the substituent containing a heteroatom include one or more selected from the group consisting of a hydroxy group (-OH), an amino group (-NH), and a thiol group (-SH). Specific examples of hydrocarbon groups having 1 to 8 carbon atoms and substituted with a substituent containing a heteroatom include hydroxyalkylene groups such as a hydroxyethylene group (-CH(OH)CH-), a hydroxypropylene group (-CHCH(OH)CH-), and a hydroxybutylene group (-CHCHCH(OH)CH-); and polyhydroxyalkylene groups such as a group obtained by removing the amino group (-NH-) and the terminal hydroxy group (-OH) from D-glucamine.

[0056] The number of carbon atoms in the hydrocarbon group having 1 to 8 carbon atoms in R3 is not particularly limited, but may be, for example, 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, or 6 or more, or 8 or less, 7 or less, 6 or less, 5 or less, 4 or less, or 3 or less, or any combination thereof that does not contradict. Specifically, it may be, for example, 1 to 8, 2 to 7, 3 to 6, 4 to 5, 6 to 8, 1 to 4, or 2 to 3.

[0057] In general formula (3), R4 is not particularly limited as long as it is a group containing a hydrocarbon group having 1 to 8 carbon atoms. R3 may be saturated or unsaturated, branched or linear, or may have a ring structure. Specific examples of the hydrocarbon group having 1 to 8 carbon atoms include linear alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and octyl; 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, cyclobutylbutyl, and cyclopentylbutyl; and alkenyl groups such as propenyl, butenyl, pentenyl, and hexenyl. Among these, branched or straight chain alkyl groups are preferred, and straight chain alkyl groups are more preferred.

[0058] Furthermore, the group containing a hydrocarbon group having 1 to 8 carbon atoms in R4 may contain a heteroatom, such as one or more selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom. Examples of groups containing a hydrocarbon group having 1 to 8 carbon atoms and containing a heteroatom include those in which one or more hydrogen atoms of the hydrocarbon group having 1 to 8 carbon atoms are substituted with a substituent containing a heteroatom. Examples of the substituent containing a heteroatom include one or more selected from the group consisting of a hydroxy group (-OH), an amino group (-NH), and a thiol group (-SH). Examples of groups containing a hydrocarbon group having 1 to 8 carbon atoms substituted with a substituent 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; dialkylamino groups such as a dimethylamino group, a diethylamino group, a dipropylamino group, and a dibutylamino 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; azapropenyl group, an azabutenyl group, an azapentenyl group, an azahexenyl group, an N,N-dimethylaminoprop ... azaalkenyl groups such as an oxaethyl group, an N,N-dimethylaminobutenyl group, an N,N-dimethylaminohexenyl group, or an N,N-diethylaminopropenyl group; oxaalkyl groups such as an oxaethyl group, an oxapropyl group, an oxabutyl group, an oxapentyl group, an oxahexyl group, an oxaheptyl group, or an oxaoctyl group; oxaalkyl groups such as an oxapropenyl group, an oxabutenyl group, an oxopentenyl group, an oxahexenyl group, an oxaheptenyl group, or an oxaoctenyl group; thioalkyl groups such as a thiobutyl group, a thiopentyl group, a thiohexyl group, a thioheptyl group, or a thiooctyl group; thioalkenyl groups such as a thiopentenyl group, a thiohexenyl group, a thioheptenyl group, or a thiooctenyl group; hydroxyalkoxyalkyl groups such as a hydroxyethoxyethyl group, a hydroxyethoxypropyl group, a hydroxyethoxybutyl group, a hydroxypropoxyethyl group, a hydroxypropoxypropyl group, or a hydroxypropoxybutyl group;Examples of such alkyl groups include alkoxyalkoxyalkyl groups such as methoxyethoxyethyl, methoxyethoxypropyl, methoxyethoxybutyl, methoxypropoxyethyl, methoxypropoxypropyl, and methoxypropoxybutyl; dihydroxyalkyl groups such as dihydroxyethyl, dihydroxypropyl, and dihydroxybutyl; and polyhydroxyalkyl groups such as groups obtained by removing the amino group (—NH—) from D-glucamine.

[0059] The number of carbon atoms in the hydrocarbon group having 1 to 8 carbon atoms in R4 is not particularly limited, and may be, for example, 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, or 6 or more, or 8 or less, 7 or less, 6 or less, 5 or less, 4 or less, or 3 or less, or any compatible combination thereof.Specifically, the number of carbon atoms in the hydrocarbon group having 1 to 8 carbon atoms in R4 may be, for example, 1 to 8, 2 to 7, 3 to 6, 4 to 5, 6 to 8, 1 to 4, or 2 to 3.

[0060] The amine B may be used alone or in combination of two or more.

[0061] The amount of amine B charged is not particularly limited, and may be, for example, 30 mol% or more, 32 mol% or more, or 35 mol% or more, or 75 mol% or less, 70 mol% or less, or 65 mol% or less, relative to the number of moles of the succinimide-derived monomer units. Specific examples of the amount of amine B charged may be 30 mol% to 75 mol%, 32 mol% to 70 mol%, or 35 mol% to 65 mol%. Furthermore, when step (b) is carried out after step (a), the amount of amine B charged is preferably greater than the amount required for the reaction in order to promote the reaction in step (b).

[0062] With regard to the polymer containing a monomer unit derived from succinimide to be subjected to step (b), the explanation in the above section [Polymer containing a monomer unit derived from succinimide] is incorporated herein by reference.

[0063] Solvent b contains one or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone. The one or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone function as a solvent for dissolving a polymer containing a monomer unit derived from succinimide. Dimethyl sulfoxide and N-methylpyrrolidone are particularly preferred due to their low toxicity. Therefore, the one or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone are preferably one or more selected from the group consisting of dimethyl sulfoxide and N-methylpyrrolidone. One or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone may be used alone or in combination of two or more.

[0064] As long as the reaction in step (b) can proceed, the solvent b may further contain one or more solvents other than dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone. Specifically, the solvent b may further contain an aprotic polar organic solvent such as dimethylacetamide (DMAc), dimethylimidazolidinone (DMI), sulfolane, 3-methoxy-N,N-dimethylpropanamide, or 3-butoxy-N,N-dimethylpropanamide.

[0065] The content of one or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone in solvent b is not particularly limited as long as the reaction in step (b) can proceed, and may be, for example, 70% by weight or more, 80% by weight or more, 90% by weight or more, or 95% by weight or more, or 100% by weight or less, 95% by weight or less, 90% by weight or less, or 80% by weight or less, or any compatible combination thereof. The total content may be, for example, 70% by weight to 100% by weight, 80% by weight to 95% by weight, 90% by weight to 95% by weight, 95% by weight to 100% by weight, 80% by weight to 90% by weight, or 70% by weight to 80% by weight.

[0066] The concentration of the polymer containing a monomer unit derived from succinimide in the solvent b is not particularly limited, but may be, for example, 1.0% by weight or more, 3.0% by weight or more, 5.0% by weight or more, 10.0% by weight or more, or The concentration of the polymer containing a monomer unit derived from succinimide in solvent b may be, for example, 1.0 to 50.0 wt%, 3.0 to 40.0 wt%, 5.0 to 30.0 wt%, 10.0 to 20.0 wt%, 15.0 to 50.0 wt%, 20.0 to 40.0 wt%, 1.0 to 15.0 wt%, or 3.0 to 10.0 wt%.

[0067] Step (b) can be carried out by a known method. Specific procedures for step (b) include, for example, dissolving a polymer containing a succinimide-derived monomer unit in a solvent, adding dropwise a solution of amine B to the solution, and reacting the resulting mixture under a predetermined temperature condition.

[0068] The temperature conditions for step (b) are not particularly limited as long as the progress of the reaction can be substantially maintained. Step (b) may be carried out at a temperature of, for example, 5° C. or higher, 10° C. or higher, 15° C. or higher, 20° C. or higher, 25° C. or higher, 30° C. or higher, or 35° C. or higher, or at a temperature of 150° C. or lower, 140° C. or lower, 130° C. or lower, 120° C. or lower, 110° C. or lower, 100° C. or lower, 95° C. or lower, 90° C. or lower, 85° C. or lower, 80° C. or lower, 75° C. or lower, 70° C. or lower, 65° C. or lower, or 60° C. or lower. Step (b) may be carried out at a temperature of, for example, 5°C to 150°C, 10°C to 140°C, 15°C to 130°C, 20°C to 120°C, 25°C to 110°C, 30°C to 100°C, 35°C to 95°C, 5°C to 90°C, 10°C to 85°C, 15°C to 80°C, 20°C to 75°C, 25°C to 70°C or less, 30°C to 65°C, or 35°C to 60°C.

[0069] The reaction time of step (b) is not particularly limited as long as the reaction of step (b) can proceed, but may be, for example, 5 minutes or more, 10 minutes or more, 20 minutes or more, 30 minutes or more, 1 hour or more, 2 hours or more, 3 hours or more, 4 hours or more, 5 hours or more, 6 hours or more, or 7 hours or more, or 15 hours or less, 10 hours or less, 9 hours or less, 8 hours or less, 7 hours or less, 6 hours or less, 5 hours or less, 4 hours or less, 3 hours or less, 2 hours or less, 1 hour or less, or 30 minutes or less, or any combination thereof that does not contradict. Specifically, it may be, for example, 5 minutes to 15 hours, 10 minutes to 10 hours, 20 minutes to 9 hours, 30 minutes to 8 hours, 1 hour to 7 hours, 2 hours to 6 hours, 3 hours to 5 hours, 4 hours to 15 hours, 5 hours to 10 hours, 6 hours to 9 hours, 7 hours to 8 hours, 5 minutes to 4 hours, 10 minutes to 3 hours, 20 minutes to 2 hours, 30 minutes to 1 hour, or 5 minutes to 30 minutes.

[0070] The reaction product obtained in step (b) may be a polymer containing succinimide-derived monomer units in which all of the succinimide-derived monomer units have been modified with amine B, or a portion of the succinimide-derived monomer units may remain unmodified.

[0071] When the production method of the present disclosure includes step (a) and step (b), the molar ratio of the amount of amine A charged to the amount of amine B charged is not particularly limited, and may be, for example, 25 / 75 to 60 / 40, or 30 / 70 to 60 / 40.

[0072] [Step (c)] Step (c) is a step of crosslinking the polymer containing the succinimide-derived monomer unit with a crosslinking agent in the presence of solvent c.

[0073] In step (c), a crosslinked structure is formed in the polymer by a crosslinking agent. The crosslinked structure can be formed by any crosslinking agent capable of forming a crosslinked moiety. The crosslinking agent is not particularly limited, but examples thereof include crosslinking agents that form amide bonds as crosslinked moieties, and specifically, polyfunctional amines.

[0074] The polyfunctional amine is preferably an amine having at least two amino groups, one or more of which is selected from the group consisting of primary and secondary amino groups. Examples of diamines include aliphatic diamines such as ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 1,2-butanediamine, 1,3-butanediamine, 1,4-butanediamine, 1,2-pentanediamine, 1,3-pentanediamine, 1,4-pentanediamine, 1,5-pentanediamine, 1,2-hexanediamine, 1,3-hexanediamine, 1,4-hexanediamine, 1,5-hexanediamine, hexamethylenediamine, 1,7-pentanediamine, 1,8-octanediamine, 1,10-diaminodecane (DAD), and 1,12-dodecyldiamine; Examples of suitable polyfunctional amines include aliphatic diamines containing an aromatic ring, such as norbornene diamine; alicyclic diamines, such as norbornene diamine; 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)), polyoxyethylene diamine, and polyoxypropylene diamine; amino acids and derivatives thereof having an amino group in the side chain, such as lysine and ornithine; and monoamino compounds linked by disulfide bonds, such as cystine and cystamine, and derivatives thereof. The polyfunctional amine preferably contains one or more selected from the group consisting of aliphatic diamines, alicyclic diamines, and ether-based diamines. The polyfunctional amine preferably does not contain the above amino acids and their derivatives. The polyfunctional amine is preferably one or more selected from the group consisting of aliphatic diamines and ether-based diamines, from the viewpoints of having a flexible structure that makes it difficult for insoluble matter to be generated during the crosslinking reaction and of making the crosslinking reaction easier to control.

[0075] Examples of polyfunctional amines other than diamines include tris(2-aminoalkyl)amines (where the carbon atom number of the alkyl is preferably 1 to 5, and more preferably 2 to 4), such as tris(2-aminoethyl)amine (TREN) and tris(3-aminopropyl)amine; diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

[0076] Among these, preferred examples of polyfunctional amines include 1,2-bis(2-aminoethoxy)ethane (AEE), bis[2-(3-aminopropoxy)ethyl ether (APEE)], tris(2-aminoethyl)amine (TREN), 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, hexamethylenediamine, 1,7-pentanediamine, 1,8-octanediamine, 1,10-diaminodecane (DAD), and 1,12-dodecyldiamine.

[0077] The crosslinking agent may be used alone or in combination of two or more.

[0078] The amount of the crosslinking agent used is not particularly limited, but may be, for example, 0.1 mol% or more, 0.3 mol% or more, or 0.5 mol% or more, or 2.0 mol% or less, 1.8 mol% or less, or 1.7 mol% or less, relative to the number of moles of the succinimide-derived monomer units. Specifically, the amount of the crosslinking agent used may be, for example, 0.1 mol% to 2.0 mol%, 0.3 mol% to 1.8 mol%, or 0.5 mol% to 1.7 mol%.

[0079] With regard to the polymer containing a monomer unit derived from succinimide, which is subjected to step (c), the explanation in the section "Polymer containing a monomer unit derived from succinimide" above is incorporated herein by reference.

[0080] The solvent c contains one or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone. The one or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone are preferably used as a solvent for succinimide. The solvent acts as a solvent for dissolving a polymer containing the monomer units derived from the dimethylformamide. Dimethyl sulfoxide and N-methylpyrrolidone are particularly preferred due to their low toxicity. Therefore, it is preferred that the one or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone are one or more selected from the group consisting of dimethyl sulfoxide and N-methylpyrrolidone. One or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone may be used alone or in combination of two or more.

[0081] As long as the reaction in step (c) can proceed, the solvent c may further contain one or more compounds selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone, and a compound having at least one hydroxyl group. Specifically, the solvent c may further contain an aprotic polar organic solvent such as dimethylacetamide (DMAc), dimethylimidazolidinone (DMI), sulfolane, 3-methoxy-N,N-dimethylpropanamide, or 3-butoxy-N,N-dimethylpropanamide.

[0082] The concentration of the polymer containing a monomer unit derived from succinimide in solvent c is not particularly limited, and may be, for example, 1.0 wt % or more, 3.0 wt % or more, 5.0 wt % or more, 10.0 wt % or more, 15.0 wt % or more, or 20.0 wt % or more, or 50.0 wt % or less, 40.0 wt % or less, 30.0 wt % or less, 20.0 wt % or less, 15.0 wt % or less, or 10.0 wt % or less, or any compatible combination thereof. The concentration of the polymer containing a monomer unit derived from succinimide in solvent c may be, for example, 1.0 wt % to 50.0 wt %, 3.0 wt % to 40.0 wt %, 5.0 wt % to 30.0 wt %, 10.0 wt % to 20.0 wt %, 15.0 wt % to 50.0 wt %, 20.0 wt % to 40.0 wt %, 1.0 wt % to 15.0 wt %, or 3.0 wt % to 10.0 wt %.

[0083] Step (c) can be carried out by a known method. Specific procedures for step (c) include, for example, dissolving a polymer containing a monomer unit derived from succinimide in a solvent, adding dropwise a solvent solution containing a crosslinking agent, and reacting the resulting mixture under a predetermined temperature condition.

[0084] The temperature conditions for step (c) are not particularly limited as long as the progress of the reaction can be substantially maintained. Step (c) may be carried out at a temperature of, for example, 5° C. or higher, 10° C. or higher, 15° C. or higher, 20° C. or higher, 25° C. or higher, 30° C. or higher, or 35° C. or higher, or at a temperature of 150° C. or lower, 140° C. or lower, 130° C. or lower, 120° C. or lower, 110° C. or lower, 100° C. or lower, 95° C. or lower, 90° C. or lower, 85° C. or lower, 80° C. or lower, 75° C. or lower, 70° C. or lower, 65° C. or lower, or 60° C. or lower. Step (c) may be carried out at a temperature of, for example, 5°C to 150°C, 10°C to 140°C, 15°C to 130°C, 20°C to 120°C, 25°C to 110°C, 30°C to 100°C, 35°C to 95°C, 5°C to 90°C, 10°C to 85°C, 15°C to 80°C, 20°C to 75°C, 25°C to 70°C or less, 30°C to 65°C, or 35°C to 60°C.

[0085] The reaction time for step (c) is not particularly limited as long as the reaction of step (c) can proceed, but may be, for example, 5 minutes or more, 10 minutes or more, 20 minutes or more, 30 minutes or more, 1 hour or more, 2 hours or more, 3 hours or more, 4 hours or more, 5 hours or more, 6 hours or more, or 7 hours or more, or 15 hours or less, 10 hours or less, 9 hours or less, 8 hours or less, 7 hours or less, 6 hours or less, 5 hours or less, 4 hours or less, 3 hours or less, 2 hours or less, 1 hour or less, or 30 minutes or less, or any combination thereof that does not contradict. Specifically, it may be, for example, 5 minutes to 15 hours, 10 minutes to 10 hours, 20 minutes to 9 hours, 30 minutes to 8 hours, 1 hour to 7 hours, 2 hours to 6 hours, 3 hours to 5 hours, 4 hours to 15 hours, 5 hours to 10 hours, 6 hours to 9 hours, 7 hours to 8 hours, 5 minutes to 4 hours, 10 minutes to 3 hours, 20 minutes to 2 hours, 30 minutes to 1 hour, or 5 minutes to 30 minutes.

[0086] The reaction product obtained in step (c) is a polymer containing succinimide-derived monomer units in which at least a portion of the succinimide-derived monomer units has been crosslinked.

[0087] The production method of the present disclosure may include only one of steps (a), (b), and (c), or may include two or more steps. When the production method includes two or more steps, the solvents a to c may be different solvents or the same solvent.

[0088] When the manufacturing method of the present disclosure includes any two of steps (a), (b), and (c), the steps may be performed in any order. For example, when the manufacturing method of the present disclosure includes steps (a) and (b), the steps may be performed in the order of steps (a) and (b), or in the order of steps (b) and (a), or steps (a) and (b) may be performed simultaneously. Furthermore, when the manufacturing method of the present disclosure includes steps (a) and (c), the steps may be performed in the order of steps (a) and (c), or in the order of steps (c) and (a), or steps (a) and (c) may be performed simultaneously. Furthermore, when the manufacturing method of the present disclosure includes steps (b) and (c), the steps may be performed in the order of steps (b) and (c), or in the order of steps (c) and (b), or steps (b) and (c) may be performed simultaneously. The case where two steps are carried out simultaneously includes the case where one step is carried out during the other step.

[0089] When the manufacturing method of the present disclosure includes steps (a), (b), and (c), the steps may be performed in any order. For example, the steps may be performed in the order of steps (a), (b), and (c); steps (a), (c), and (b); steps (b), (a), and (c); steps (b), (c), and (a); steps (c), (a), and (b); or steps (c), (b), and (a). Two or more of steps (a), (b), and (c) may be performed simultaneously. Note that the term "two or more steps performed simultaneously" includes cases where one step is performed midway through the other step.

[0090] In particular, when the production method of the present disclosure includes steps (a), (b), and (c), the steps are preferably performed in the order of step (c), step (a), and step (b). In other words, the production method of the present disclosure preferably includes the following steps (c), step (a), step (b), and step (d). Step (c): A step of crosslinking a polymer containing a monomer unit derived from succinimide with a crosslinking agent in the presence of a solvent c, Step c, wherein the solvent c contains one or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone. Step (a): A step of modifying the reaction product obtained in step (c) with an amine represented by general formula (1) in the presence of a solvent a, The solvent a contains one or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone. Step (b): A step of modifying the reaction product obtained in step (a) with one or more amines selected from the group consisting of an amine represented by general formula (2) and an amine represented by general formula (3) in the presence of a solvent b, The solvent b contains one or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone. 4 represents a hydrocarbon group having 1 to 8 carbon atoms which may contain a heteroatom. Step (d): A step of drying the reaction liquid obtained in step (b) using a drum dryer.

[0091] When the "polymer containing succinimide-derived monomer units" used in step (c) is polysuccinimide, the content of polysuccinimide in the reaction system at the start of step (c) is preferably 8.0 wt% or more, more preferably 10.0 wt% or more, even more preferably 12.0 wt% or more, and even more preferably 14.0 wt% or more. On the other hand, it is preferably 24.0 wt% or less, more preferably 22.0 wt% or less, and even more preferably 20.0 wt% or less. For example, the content is preferably 8.0 wt% to 24.0 wt%, more preferably 10.0 wt% to 22.0 wt%, even more preferably 12.0 wt% to 20.0 wt%, and even more preferably 14.0 wt% to 20.0 wt%. When the polysuccinimide content is within this range, a polyaspartic acid derivative with a high molecular weight can be obtained, and gelation of the polyaspartic acid derivative can be easily suppressed.

[0092] When the "polymer containing a succinimide-derived monomer unit" subjected to step (c) contains one or more units selected from the group consisting of the monomer unit AU and the monomer unit BU (e.g., when step (a) or step (b) is performed before step (c)), the content of the polymer containing a succinimide-derived monomer unit in the reaction system at the start of the reaction in step (c) is preferably 10.0 wt% or more, more preferably 12.0 wt% or more, and even more preferably 14.0 wt% or more. On the other hand, it is preferably 40.0 wt% or less, more preferably 35.0 wt% or less, and even more preferably 30.0 wt% or less. For example, the content is preferably 10.0 wt% to 40.0 wt%, more preferably 12.0 wt% to 35.0 wt%, and even more preferably 14.0 wt% to 30.0 wt%. When the content of the polymer containing a monomer unit derived from succinimide is within this range, a polyaspartic acid derivative with a high molecular weight can be obtained, and gelation of the polyaspartic acid derivative can be easily suppressed.

[0093] In the polyaspartic acid derivative obtained by the production method of the present disclosure, unreacted imide rings may remain. The production method of the present disclosure may further include a step of modifying the polymer containing succinimide-derived monomer units with a monoamine other than amine A and amine B before step (d). In this case, the step (a), step (b), and step (c) may be performed in any order. When the step (a), step (b), and step (c) are included, the total amount of amine A and amine B charged may be 80.0 mol% or more, 90.0 mol% or more, or 95.0 mol% or more, or 99.0 mol% or less, 95.0 mol% or less, or 90.0 mol% or less, or any combination thereof, based on the total amount of amine A, amine B, and monoamines other than amine A and amine B charged. Specifically, it may be, for example, 80.0 mol % to 99.0 mol %, 90.0 mol % to 95.0 mol %, or 80.0 mol % to 90.0 mol %.

[0094] [Step (d)] The production method of the present disclosure includes the following step (d) after one or more steps selected from the group consisting of step (a), step (b), and step (c): Step (d): A step of drying the obtained reaction liquid with a drum dryer.

[0095] By the step (d), a fibrous polyaspartic acid derivative having almost no tackiness can be obtained. Furthermore, since step (d) yields a polyaspartic acid derivative with a large particle size, when further purified by washing with a poor solvent after step (d), the amount of poor solvent absorbed in the slurry is reduced, resulting in a smaller overall weight and volume of the slurry, making it easier to handle. Furthermore, when the slurry is subsequently dried, the drying time required to remove the poor solvent is shortened. On the other hand, conventional reprecipitation methods yield very fine particulate polyaspartic acid derivatives, so washing with a poor solvent results in a large amount of poor solvent being absorbed into the slurry, making the slurry difficult to handle and requiring prolonged drying to remove the poor solvent. This is presumably because the reprecipitation method dissolves the reaction solvent from the reaction solution into the poor solvent, which also loosens the polymer entanglements, resulting in a smaller particle size of the polyaspartic acid derivative. Furthermore, step (d) is presumably due to the instantaneous evaporation of the reaction solvent (solvent a, solvent b, or solvent c) by the drum dryer, resulting in the precipitation of the polyaspartic acid derivative while maintaining the entanglement of the polymer.

[0096] In particular, when the production method of the present disclosure includes one or more steps selected from step (a) and step (b), the amount of unreacted amine A and amine B (free amine) remaining in the polyaspartic acid derivative can be reduced by step (d). This is presumably because, while free amines form hydrogen bonds with carbonyls and the like of the polyaspartic acid derivative and are difficult to remove by reprecipitation, the use of a drum dryer makes it easy for the hydrogen bonds to be cleaved by heating. A low amount of free amines can reduce the amount of acid required for pH adjustment when the polyaspartic acid derivative is used for a desired purpose such as cosmetics. Furthermore, while the viscosity of polyaspartic acid derivatives tends to decrease when exposed to acid, the amount of acid used for pH adjustment can be reduced, making it easier to maintain a high viscosity of a composition containing the polyaspartic acid derivative.

[0097] The type of drum dryer used in step (d) is not particularly limited, and examples thereof include atmospheric pressure drum dryers and vacuum drum dryers. Vacuum drum dryers are more preferred because they suppress decomposition of the polyaspartic acid derivative through purification at low temperatures. The number of drums is also not particularly limited, and may be, for example, a single-drum type or a double-drum type, although a double-drum type is preferred from the viewpoint of productivity.

[0098] The drum surface temperature of the drum dryer is preferably at least 5°C higher, more preferably at least 10°C higher, and even more preferably at least 30°C higher, than the temperature at which the solvent in the resulting reaction liquid evaporates according to the equilibrium vapor pressure curve of the solvent under the internal vapor pressure conditions of the drum dryer in step (d). On the other hand, the drum surface temperature of the drum dryer is preferably at most 60°C higher, preferably at most 50°C higher, and preferably at most 40°C higher, than the temperature at which the solvent in the resulting reaction liquid evaporates according to the equilibrium vapor pressure curve of the solvent under the internal vapor pressure conditions of the drum dryer in step (d). Specifically, the drum surface temperature of the drum dryer is preferably at most 5°C to 60°C higher, more preferably at most 10°C to 50°C higher, and even more preferably at most 30°C to 40°C higher, than the temperature at which the solvent in the resulting reaction liquid evaporates according to the equilibrium vapor pressure curve of the solvent under the internal vapor pressure conditions of the drum dryer in step (d). In the present disclosure, the unit of "temperature" is "°C."

[0099] When the solvent of the obtained reaction solution is only one of dimethylformamide, dimethyl sulfoxide, or N-methylpyrrolidone, the drum surface temperature of the drum dryer can be determined based on the equilibrium vapor pressure curve of that solvent (Figure 1). When the solvent of the obtained reaction liquid is a mixed solvent consisting of two or more solvents, and the mixed solvent forms an azeotrope, an equilibrium vapor pressure curve of the mixed solvent can be created by multiplying the vapor pressure at each temperature by the mixing ratio (mol%) of the solvents according to the vapor pressure curve of each solvent and summing the values ​​obtained by dividing the result by 100, and the drum surface temperature of the drum dryer can be determined based on the equilibrium vapor pressure curve. On the other hand, when the mixed solvent does not form an azeotrope, the drum surface temperature of the drum dryer can be determined based on the vapor pressure curve of the solvent that shows the highest temperature at each vapor pressure.

[0100] The temperature of the drum surface of the drum dryer is not particularly limited as long as the desired effect can be obtained, and may be, for example, 20°C or higher, 40°C or higher, 60°C or higher, 80°C or higher, 100°C or higher, 120°C or higher, or 140°C or higher; or 200°C or lower, 180°C or lower, 160°C or lower, 140°C or lower, 120°C or lower, 100°C or lower, or 80°C or lower, or any compatible combination thereof. The temperature of the drum surface of the drum dryer may be, for example, 20°C to 200°C, 40°C to 180°C, 60°C to 160°C, 60°C to 140°C, 80°C to 120°C, 100°C to 200°C, 120°C to 180°C, or 140°C to 160°C. The temperature of the drum surface of the drum dryer is preferably 20°C to 200°C, more preferably 40°C to 180°C, and even more preferably 60°C to 160°C.

[0101] The internal steam pressure of the drum dryer is not particularly limited as long as the desired effect can be obtained, and may be, for example, 0.1 kPa or more, 0.5 kPa or more, 1 kPa or more, 2 kPa or more, 3 kPa or more, 5 kPa or more, 10 kPa or more, 15 kPa or more, 20 kPa or more, or 25 kPa or more, or 50 kPa or less, 45 kPa or less, 40 kPa or less, 35 kPa or less, 30 kPa or less, 25 kPa or less, 20 kPa or less, 15 kPa or less, 10 kPa or less, or 5 kPa or less, or any compatible combination thereof. The internal steam pressure of the drum dryer may be, for example, 0.1 kPa to 50 kPa, 0.5 kPa to 45 kPa, 1 kPa to 40 kPa, 2 kPa to 35 kPa, 3 kPa to 30 kPa, 5 kPa to 25 kPa, 10 kPa to 20 kPa, 15 kPa to 50 kPa, 20 kPa to 45 kPa, or 25 kPa to 40 kPa. The internal steam pressure of the drum dryer is preferably 0.1 kPa to 50 kPa, more preferably 0.5 kPa to 30 kPa, and even more preferably 1 kPa to 20 kPa.

[0102] The rotation speed of the drum dryer is adjusted as appropriate depending on the size of the drum, the amount of reaction liquid to be treated, etc., and can be set to, for example, 0.5 rpm or more and 10 rpm or less.

[0103] The reaction solution subjected to step (d) becomes a dried sheet-like product in step (d), and this sheet can be pulverized using a known pulverizer such as a cutter mill or a pin mill to obtain a powdery dried product (polyaspartic acid derivative).

[0104] The dried product obtained in step (d) may be washed by mixing and stirring with a poor solvent for the polyaspartic acid derivative (e.g., one or more selected from the group consisting of ethyl acetate, acetone, methyl ethyl ketone, acetonitrile, methyl ethyl ketone, and water), and then the precipitate is filtered to obtain a slurry, which may be dried by a known drying method (e.g., vacuum drying). When the dried product obtained in step (d) is washed with or filtered from a poor solvent and then vacuum-dried at 60°C for 12 hours, the weight ratio of the poor solvent evaporated by vacuum drying to the weight of the slurry is not particularly limited, but may be, for example, 3.0 wt% or more, 5.0 wt% or more, or 7.0 wt% or more, or 15.0 wt% or less, 13.0 wt% or less, or 11.0 wt% or less. Specifically, it may be, for example, 3.0 wt% to 15.0 wt%, 5.0 wt% to 13.0 wt%, or 7.0 wt% to 11.0 wt%. Since the particle size of the polyaspartic acid derivative dried with a drum dryer is large, the amount of poor solvent absorbed in the polyaspartic acid derivative slurry after washing with the poor solvent or filtering is reduced, and the amount of poor solvent volatilized during subsequent drying is also reduced. The ratio of the weight of the poor solvent evaporated by drying to the weight of the slurry can be calculated by the following formula: The ratio can be adjusted by the operating conditions of the drum dryer, etc. {(slurry weight)-(weight of polyaspartic acid derivative after vacuum drying)} / (slurry weight)×100

[0105] [Polyaspartic acid derivatives] The polyaspartic acid derivative produced by the production method of the present disclosure is a polymer formed by peptide bonds of aspartic acid. The bond may be either an α-bond or a β-bond. The bond type may be the same or different for each structural unit.

[0106] The polyaspartic acid derivatives produced by the production method of the present disclosure contain one or more of the α- or β-polyaspartic acid monomer unit AU represented by the above general formula (5), the α- or β-polyaspartic acid monomer unit B'-U represented by the above general formula (6), the α- or β-polyaspartic acid monomer unit B''-U represented by the above general formula (7), and the α- or β-polyaspartic acid monomer unit Crosslink-U represented by the above general formula (8). In the present disclosure, the α- or β-polyaspartic acid monomer unit AU represented by general formula (5) is also referred to as the “monomer unit AU”, one or more selected from the group consisting of the α- or β-polyaspartic acid monomer unit B′-U represented by general formula (6) and the α- or β-polyaspartic acid monomer unit B″-U represented by general formula (7) are also collectively referred to as the “monomer unit BU”, and the α- or β-polyaspartic acid monomer unit Crosslink-U represented by general formula (8) is also referred to as the “monomer unit Crosslink-U”.

[0107] The polyaspartic acid derivative containing the monomer unit AU is obtained by step (a). One molecule of the polyaspartic acid derivative may contain one type of monomer unit AU alone or two or more types.

[0108] The amount of the monomer unit AU present in the constituent monomers of the polyaspartic acid derivative is not particularly limited, but may be, for example, 20 mol% or more, 25 mol% or more, or 30 mol% or more, or 60 mol% or less, 58 mol% or less, or 57 mol% or less. Specifically, the amount of the monomer unit AU present may be, for example, 20 mol% to 60 mol%, 25 mol% to 58 mol%, or 30 mol% to 57 mol%. The amount of the monomer unit AU present can be adjusted by the amount of amine A and other raw materials charged.

[0109] The abundance of the monomer unit AU can be, for example, 1 It can be calculated from HNMR. Specifically, it can be calculated from the obtained NMR spectrum, for example, using the following formula: Abundance of monomer unit AU (mol %)=(peak integral value of methyl group of amine A / 3)×100 / ((peak integral value of methyl group of amine A / 3)+(peak integral value of methylene group of amine B / 2)+(peak integral value of methine group of succinimide))

[0110] The polyaspartic acid derivative containing the monomer unit BU is obtained by step (b). One molecule of the polyaspartic acid derivative may contain one type of monomer unit BU alone or two or more types.

[0111] The amount of the monomer units BU present in the constituent monomers of the polyaspartic acid derivative is not particularly limited, but may be, for example, 30 mol% or more, 32 mol% or more, or 35 mol% or more, or 60 mol% or less, 50 mol% or less, or 45 mol% or less. Specific examples of the amount of the monomer units BU present may be 30 mol% to 80 mol%, 32 mol% to 75 mol%, or 35 mol% to 70 mol%. The amount of the monomer units BU present can be adjusted by the amount of amine B and other raw materials charged.

[0112] The amount of the monomer unit BU present can be, for example, 1 It can be calculated from HNMR. Specifically, it can be calculated from the obtained NMR spectrum, for example, using the following formula: Abundance of monomer unit BU (mol %)=(peak integral value of methylene group of amine B / 2)×100 / ((peak integral value of methyl group of amine A / 3)+(peak integral value of methylene group of amine B / 2)+(peak integral value of methine group of succinimide))

[0113] When the polyaspartic acid derivative contains the monomer units AU and BU, the ratio of the amount (mol %) of the monomer units AU to the amount (mol %) of the monomer units BU in the polyaspartic acid derivative (also expressed as (AU) / (BU)) is not particularly limited, and may be, for example, 25 / 75 to 60 / 40, or 30 / 70 to 60 / 40.

[0114] (AU) / (BU) is, for example, 1 It can be calculated from HNMR. Specifically, it can be calculated from the obtained NMR spectrum, for example, using the following formula: (AU) / (BU)=(peak integral of methyl group of amine A / 3) / (peak integral of methylene group of amine B / 2)

[0115] A polyaspartic acid derivative containing the monomer unit Crosslink-U is obtained by step (c). The amount of crosslinking in the polyaspartic acid derivative (i.e., the amount of the monomer unit Crosslink-U present in the constituent monomers of the polyaspartic acid derivative) is not particularly limited, but may be, for example, 0.1 mol% or more, 0.3 mol% or more, or 0.5 mol% or more, or 2.0 mol% or less, 1.8 mol% or less, or 1.7 mol% or less. Specific examples of the amount of crosslinking may be 0.1 mol% to 2.0 mol%, 0.3 mol% to 1.8 mol%, or 0.5 mol% to 1.7 mol%. The amount of crosslinking can be adjusted by the amount of crosslinking agent and the amount of each of the other raw materials charged.

[0116] The amount of crosslinking can be calculated, for example, from the ratio (%) of the amount (number of moles) of the crosslinking agent charged to the number of moles of the monomer units derived from succinimide.

[0117] In the polyaspartic acid derivative produced by the production method of the present disclosure, unreacted succinimide rings may remain, i.e., the polyaspartic acid derivative may contain the monomer unit represented by the above formula (2) (also referred to as "monomer unit CU").

[0118] When the polyaspartic acid derivative contains the monomer units AU, BU, and CU, the ratio of the total abundance (mol %) of the monomer units AU and BU to the abundance (mol %) of the monomer unit CU in the polyaspartic acid derivative (also represented as [(AU)+(BU)] / (CU)) is not particularly limited and may be, for example, 80 / 20 to 99 / 1, 85 / 15 to 98 / 1, 90 / 10 to 98 / 2, or 90 / 10 to 97 / 2.

[0119] [(AU)+(BU)] / (CU), for example, 1 It can be calculated from HNMR. Specifically, it can be calculated from the obtained NMR spectrum, for example, using the following formula: [(AU) + (BU)] / (CU) = [(peak integral of methyl group of amine A / 3) + (peak integral of methylene group of amine B / 2)] / (peak integral of methine group of succinimide)

[0120] The bonding form of the monomer units AU, BU, CU, 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 structures, but is preferably a linear structure with a slight three-dimensional network structure.

[0121] The polyaspartic acid derivative may contain a monomer unit other than the monomer units AU, BU, CU, and Crosslink-U. For example, the polyaspartic acid derivative may contain a monomer unit in which succinimide is modified with a monoamine other than amine A and amine B.

[0122] The polyaspartic acid derivative may also contain, for example, one or more monomer units selected from the group consisting of a monomer unit represented by the following general formula (9), a monomer unit represented by the following general formula (10), and a monomer unit represented by the following general formula (11).

[0123] [ka] (In the formula, R1 represents a group containing a hydrocarbon group having 3 to 22 carbon atoms which may contain a heteroatom.)

[0124] The monomer unit represented by general formula (9) is a carboxylic acid ammonium salt formed by bonding a carboxylic acid, which is a monomer formed by ring-opening the succinimide ring of the monomer unit CU, to the amine A remaining after step (a). The explanation for R1 in general formula (9) is the same as that for R1 in general formula (1).

[0125] [ka] (In the formula, R2 represents a group containing a hydrocarbon group having 1 to 16 carbon atoms which may contain a heteroatom.)

[0126] [ka] (In the formula, R3 represents a group containing a hydrocarbon group having 1 to 8 carbon atoms which may contain a heteroatom, and R4 represents a group containing a hydrocarbon group having 1 to 8 carbon atoms which may contain a heteroatom.)

[0127] The monomer unit represented by general formula (10) and the monomer unit represented by general formula (11) are each an ammonium carboxylate salt formed by combining a carboxylic acid, which is a monomer formed by ring-opening the succinimide ring of the monomer unit CU, with the amine B remaining after step (b). The explanation for R2 in general formula (10) is incorporated herein by reference. Furthermore, the explanation for R3 and R4 in general formula (3) is incorporated herein by reference.

[0128] When the production method of the present disclosure includes at least step (a) and step (b) among steps (a), (b), and (c), the amount of unreacted amine A and / or amine B (free amine) in the resulting polyaspartic acid derivative is not particularly limited, but may be, for example, 0.0 wt% or more, 0.1 wt% or more, 0.2 wt% or more, or 0.3 wt% or more, or 1.0 wt% or less, 0.8 wt% or less, 0.6 wt% or less, or 0.5 wt% or less. Specifically, it may be, for example, 0.0 wt% to 1.0 wt%, 0.1 wt% to 0.8 wt%, 0.2 wt% to 0.6 wt%, or 0.3 wt% to 0.5 wt%. The amount of free amine can be reduced by drying with a drum dryer in step (d). The amount of free amine is 1 The amount of free amine B can be calculated by HNMR. For example, when amine A is Farmin 20D (a mixture of 1% decylamine, 96% dodecylamine (DA), and 3% tetradecylamine, manufactured by Kao Corporation) and amine B is 3-amino-1-propanol, the amount of free amine B can be calculated by the procedure shown in the Examples. The amount of free amine can be adjusted by the operating conditions of the drum dryer, the amount of the amine charged, etc.

[0129] The weight average molecular weight (Mw) of the polyaspartic acid derivative is not particularly limited, and may be, for example, 70,000 or more, 80,000 or more, 100,000 or more, 120,000 or more, 150,000 or more, 200,000 or more, or 250,000 or more, or 1,000,000 or less, 700,000 or less, 600,000 or less, 500,000 or less, 400,000 or less, 300,000 or less, or 200,000 or less, or any compatible combination thereof. Specifically, it may be, for example, 70,000 to 1,000,000, 80,000 to 700,000, 100,000 to 600,000, 120,000 to 500,000, 150,000 to 400,000, 200,000 to 500,000, 250,000 to 400,000, or 70,000 to 200,000. The weight-average molecular weight can be adjusted by the molecular weight of the polymer containing a monomer unit derived from succinimide, the types of amine A and amine B, etc.

[0130] When an aqueous solution containing 1.5 wt % of a polyaspartic acid derivative and 0.2 wt % of citric acid is prepared, the shear viscosity of the aqueous solution is not particularly limited, and may be, for example, 1000 mPa·s or more, 1500 mPa·s or more, 2000 mPa·s or more, 2500 mPa·s or more, or 3000 mPa·s or more, or 10000 mPa·s or less, 8000 mPa·s or less, 7000 mPa·s or less, 6000 mPa·s or less, or 5000 mPa·s or less. Specifically, the shear viscosity may be, for example, 1000 mPa·s to 10000 mPa·s, 1500 mPa·s to 8000 mPa·s, 2000 mPa·s to 7000 mPa·s, 2500 mPa·s to 6000 mPa·s, or 3000 mPa·s to 5000 mPa·s. The shear viscosity can be adjusted by the molecular weight of the polymer containing the succinimide-derived monomer unit, the types of amine A and amine B, the operating conditions of the drum dryer, etc. In this disclosure, the shear viscosity refers to the shear viscosity value at a shear rate of 5 (1 / s) after preshearing for 15 seconds at a shear rate of 10 (1 / s) and leaving it to stand for 30 seconds using a rotational rheometer (MCR102, manufactured by Anton Paar) under conditions of a cone plate CP-25, a gap of 0.106 mm, and a measurement temperature of 25°C.

[0131] The polyaspartic acid derivatives produced by the method for producing a polyaspartic acid derivative of the present disclosure have high molecular weights and high viscosities, and are therefore suitable for use as thickeners. The polyaspartic acid derivatives can be used for a variety of purposes, including, for example, skin care products, cosmetics, quasi-drugs, and pharmaceuticals. [Example]

[0132] The present invention will be described in detail below with reference to examples, but the present disclosure is not limited thereto.

[0133] [Example 1] The polyaspartic acid derivative of Example 1 was prepared according to the following procedure.

[0134] <Synthesis of Polysuccinimide (PSI)> 160 parts of aspartic acid (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 5 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 polysuccinimide (PSI) with a weight-average molecular weight of 70,000. The weight-average molecular weight of PSI was measured using the measurement method described below.

[0135] <Synthesis of polyaspartic acid derivatives> 10.0 g of PSI and 95.3 g of dimethylformamide (DMF) were placed in a reaction vessel and heated to 60°C for complete dissolution. After the temperature was lowered to 40°C, a mixture of 0.228 g of 1,2-bis(2-aminoethoxy)ethane (AEE) (1.5 mol% per mole of succinimide units) and 2.06 g of DMF was added as a crosslinking agent and allowed to react for 7 hours. The PSI content (wt%) in the reaction system during the reaction is shown in Table 1. Next, a mixture of 10.3 g of Farmin 20D (a mixture of 1% decylamine, 96% dodecylamine (DA), and 3% tetradecylamine, manufactured by Kao Corporation) (54 mol% per mole of succinimide units) and 2.00 g of DMF was added as amine A and allowed to react at 40°C for 30 minutes. Furthermore, 3.45 g (44.5 mol % relative to 1 succinimide unit) of 3-amino-1-propanol (PA) was added as amine B, and the mixture was reacted for 7 hours while maintaining the temperature in the reaction vessel at 40°C. After that, the temperature was raised to 60°C and the mixture was reacted at the same temperature for 2 hours. The resulting reaction solution was dried in a vacuum drum dryer (VD-0102, Katsuragi Industry Co., Ltd. Drying was carried out using a drying oven (manufactured by Epson) at a drum rotation speed of 1 rpm, an internal steam pressure of 3.0 kPa, and a drum surface temperature of 110°C to obtain a sheet-like solid. The resulting pulverized solid was mixed with 200 ml of ethyl acetate (EA) and washed by stirring at room temperature for 1 hour. After washing, the mixture was left to stand, and the precipitate was filtered off to obtain 24.0 g of a slurry, which was then vacuum dried at 60°C for 12 hours to obtain 22.0 g of the polyspartic acid derivative of Example 1.

[0136] [Examples 2 to 15] The polyaspartic acid derivatives of Examples 2 to 15 were obtained by the same procedure as in Example 1, except that the raw materials and solvent, as well as the temperature when dissolving PSI in the solvent and the drum dryer operating conditions were changed as shown in Table 1.

[0137] [Comparative Example 1] A reaction vessel was charged with 10.0 g of PSI obtained in the above <Synthesis of Polysuccinimide (PSI)> and 120 g of dimethylformamide (DMF) and heated to 60°C for complete dissolution. After the temperature was lowered to 40°C, a mixture of 0.228 g of 1,2-bis(2-aminoethoxy)ethane (AEE) (1.5 mol% per mole of succinimide units) as a crosslinker and 2.06 g of DMF was added and allowed to react for 7 hours. The PSI content (wt%) in the reaction system during the reaction is shown in Table 1. Next, a mixture of 10.3 g of Farmin 20D (54 mol% per mole of succinimide units) and 2.00 g of DMF was added as amine A and heated, and the mixture was allowed to react at 40°C for 30 minutes. Furthermore, 3.45 g (44.5 mol % per 1 mol of succinimide units) of 3-amino-1-propanol (PA) was added as amine B, and the mixture was reacted for 7 hours while maintaining the temperature in the reaction vessel at 40°C. After that, the temperature was raised to 60°C and the mixture was reacted at the same temperature for 2 hours. The reaction vessel was then cooled, and once it had reached room temperature, the reaction solution was poured into 1,080 g of ethyl acetate (EA) with stirring to precipitate and precipitate the reaction product, and the solid was recovered by filtration (reprecipitation step). Because the recovered solid contained a large amount of residual DMF and was sticky, it was further washed with 540 g of ethyl acetate (EA) with stirring, and 32.0 g of a slurry was recovered by filtration (washing step). The recovered slurry showed almost no stickiness. The slurry was vacuum-dried at 60°C for 12 hours to obtain 22.2 g of the polyaspartic acid derivative of Comparative Example 1.

[0138] [Comparative Examples 2 to 5] Polyaspartic acid derivatives of Comparative Examples 2 to 5 were obtained in the same manner as in Comparative Example 1, except that the raw materials, solvent, and temperature at which PSI was dissolved in the solvent were changed as shown in Table 1.

[0139] Comparative Example 6 The procedure up to the addition of amine B and reaction was the same as in Comparative Example 1, except that the raw materials, solvent, and temperature when dissolving PSI in the solvent were changed as shown in Table 1. Because the resulting reaction product had gelled, the reprecipitation step and subsequent steps were not carried out.

[0140] [Table 1]

[0141] <Calculation of volatile amount of ethyl acetate (EA)> The amount of ethyl acetate (EA) evaporated during vacuum drying in each Example and Comparative Example was calculated as the ratio (wt%) of the weight of EA evaporated from the slurry by vacuum drying to the weight of the slurry after washing with EA or filtering. Specifically, this was calculated using the following formula. The results are shown in Table 1. {(weight of slurry)-(weight of obtained polyaspartic acid derivative)} / (weight of slurry)×100

[0142] <Calculation of residual amount of amine B> The residual amount of amine B (amount of free amine B)1 Calculation was performed using HNMR according to the following procedure. 1 HNMR measurement conditions: 0.04 g of the obtained polyaspartic acid derivative was dissolved in 0.7 mL of deuterated dimethyl sulfoxide to prepare a measurement sample, which was measured using a JNM-ECZ400S (manufactured by JEOL Ltd.) under the following conditions. Observation frequency: 400MHz Chemical shift reference: TMS (tetramethylsilane) (0 ppm) Pulse Delay: 6.8 seconds Number of scans: 32 Pulse width: 45° (3.2 μs) Measurement temperature: 60℃

[0143] Next, using the obtained NMR spectrum, the remaining amount (% by weight) of amine B was calculated according to the following formula. The results are shown in Table 1. Residual amount of amine B (wt%)={A×PA molecular weight / (A×PA molecular weight + B×(PA molecular weight + C×average molecular weight of amine A + D + E)}

[0144] In the above formula, A to E represent the following values. A: (integral value of the peak of the methylene group hydrogen at the 2nd position of free PA) / 2 (The quintet peak at 1.6-1.7 ppm was used as the "peak of the methylene group hydrogen at position 2 of free PA.") B: (integral value of the peak corresponding to the methylene group hydrogen at the 2nd position of PA in the polyaspartic acid derivative) / 2 (Note that the broad peak at 1.5-1.6 ppm was used as the "peak corresponding to the methylene group hydrogen at the 2nd position of PA in the polyaspartic acid derivative.") C: (integral value of the peak of the methyl group hydrogen of DA in the polyaspartic acid derivative) / 3 (Note that the broad peak between 0.7 and 0.9 ppm was used as the "peak of the methyl group hydrogen of DA in the polyaspartic acid derivative.") D: Integral value of the peak of hydrogen bonded to the tertiary carbon of the five-membered succinimide ring × molecular weight of the five-membered succinimide ring (Note: A broad peak at 4.9 - 5.1 ppm was used as the "peak of the hydrogen bonded to the tertiary carbon of the succinimide 5-membered ring".) E: Molecular weight of the succinimide group that was denatured with amine (B + C) and ring-opened In addition, in the above formula, the "average molecular weight of amine A" is a value obtained by multiplying the molecular weight of each amine contained in amine A by its molar percentage, summing them up, and then dividing by 100.

[0145] <Measurement of the weight-average molecular weight of PSI and polyaspartic acid derivatives> In the measurement of the weight-average molecular weight of PSI, a polystyrene-equivalent value was obtained by the GPC method (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. As the eluent, dimethylformamide containing 10 mM lithium bromide was used. Also, the weight-average molecular weights of the polyaspartic acid derivatives in each Example and Comparative Example were measured in the same manner. The results are shown in Table 1.

[0146] <Measurement of viscosity> The obtained polyaspartic acid derivatives of the Examples and Comparative Examples were each dissolved in ion-exchanged water at 80°C so that the concentration became 1.8% by weight, then the pH was adjusted to 7 with a 0.2% by weight aqueous citric acid solution, and further adjusted with water at pH 7 so that the concentration became 1.5% by weight to obtain each sample. The shear viscosity of each obtained sample was measured using a rotational rheometer (MCR102, manufactured by Anton Paar). Specifically, under the conditions of a cone plate CP-25, a gap of 0.106 mm, and a measurement temperature of 25°C, a preshear was performed at a shear rate of 10 (1 / s) for 15 seconds and then allowed to stand for 30 seconds, and then the shear viscosity at a shear rate of 5 (1 / s) was measured. The results are shown in Table 1.

[0147] As shown in Table 1, in Examples 1 to 15, in which a drum dryer was used, the amount of ethyl acetate used was reduced compared to Comparative Examples 1 to 6, in which a conventional reprecipitation method was used. Furthermore, while the solids after reprecipitation in Comparative Examples 1 to 5 were sticky, in Examples 1 to 15, a fibrous polyaspartic acid derivative resembling a coarse nonwoven fabric was obtained in the form of a sheet after drum dryer drying, and it had almost no stickiness. Furthermore, since the amount of ethyl acetate volatilization was lower in Examples 1 to 15 compared to Comparative Examples 1 to 5, the amount of ethyl acetate absorbed by the filtered slurry after the washing step was clearly reduced. This demonstrated that the use of a drum dryer can improve workability in the drying step and shorten drying time. Furthermore, the amount of residual amine B in Examples 1 to 15 was lower compared to Comparative Examples 1 to 5. Polyaspartic acid derivatives tend to decrease in viscosity due to acid. Using a drum dryer reduced the amount of residual amine B, which in turn reduced the amount of acid used for pH adjustment. This suggests that viscosity reduction in compositions containing polyaspartic acid derivatives for cosmetics and the like can be suppressed.

Claims

1. One or more steps selected from the group consisting of the following steps (a), (b), and (c): and a method for producing a polyaspartic acid derivative, the method comprising step (d) after one or more steps selected from the group consisting of steps (a), (b), and (c). Step (a): A step of modifying a polymer containing a monomer unit derived from succinimide with an amine represented by the following general formula (1) in the presence of a solvent a, a step in which the solvent a contains one or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone; R １ -NH ２ (1) (In the formula, R １ represents a group containing a hydrocarbon group having 3 to 22 carbon atoms which may contain a heteroatom. Step (b): A step of modifying a polymer containing a monomer unit derived from succinimide with one or more amines selected from the group consisting of amines represented by the following general formula (2) and amines represented by the following general formula (3) in the presence of a solvent b, the solvent b contains one or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone; OH-R ２ -NH ２ (2) (In the formula, R ２ represents a group containing a hydrocarbon group having 1 to 16 carbon atoms which may contain a heteroatom. OH-R ３ -NH-R ４ (3) (In the formula, R ３ represents a group containing a hydrocarbon group having 1 to 8 carbon atoms which may contain a heteroatom, and R ４ represents a group containing a hydrocarbon group having 1 to 8 carbon atoms which may contain a heteroatom. Step (c): A step of crosslinking a polymer containing a monomer unit derived from succinimide with a crosslinking agent in the presence of a solvent c, the solvent c contains one or more selected from the group consisting of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone; Step (d): A step of drying the obtained reaction liquid with a drum dryer

2. 2. The production method according to claim 1, wherein the drum surface temperature of the drum dryer in the step (d) is at least 5°C higher than the temperature at which the solvent of the reaction solution vaporizes according to the equilibrium vapor pressure curve of the solvent under the vapor internal pressure conditions of the drum dryer in the step (d).

3. The method according to claim 1 or 2, wherein the internal steam pressure of the drum dryer in the step (d) is 0.1 kPa to 50 kPa.

4. The method according to claim 1 or 2, wherein the temperature of the drum surface of the drum dryer in the step (d) is 20°C to 200°C.

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