Copolymer, method for producing same, application of same, copolymer-containing composite particle, and dispersion thereof

Abstract

The present disclosure provides a copolymer which exhibits excellent dispersibility and satisfactory water solubility. More specifically, the present disclosure provides a copolymer containing: a constituent unit (A) derived from a monomer (a) having a hydrophilic group (other than a catechol group); and a constituent unit (B) derived from a monomer (b) having a catechol group. The hydrophilic group is a hydroxyl group and / or a phosphate group. The mass-average molecular weight of the copolymer is 500-20,000.

Description

Copolymer, its production method and use, composite particles containing the copolymer and dispersion thereof

[0001] The present disclosure relates to a copolymer, its production method and use, as well as composite particles containing the copolymer and dispersions thereof.

[0002] Conventionally, various proposals have been made for dispersing polytetrafluoroethylene (PTFE) particles, inorganic particles, etc. in an aqueous solvent.

[0003] For example, Patent Document 1 describes an aqueous dispersion of a fluorine-based resin containing 1 to 80 mass % of fluorine-based resin particles (for example, PTFE particles) having a volume average particle diameter Dv of 1 μm to 50 μm after dispersion.

[0004] Patent Document 2 describes a dispersant containing a compound having a structural unit (A) of a specific structure and a structural unit (B) derived from at least one monomer (b) selected from the group consisting of terpene-based monomers, vinyl-based monomers, and conjugated diene-based monomers.

[0005] Japanese Patent Publication No. 2019-052211 Japanese Patent Publication No. 2023-127556

[0006] However, the invention described in Patent Document 1 uses a fluorine-based surfactant, which has problems such as the tendency to accumulate in the body and persist in the environment.

[0007] Furthermore, the invention described in Patent Document 2 has the problem that the particles are not soluble in water and therefore do not disperse sufficiently in aqueous solvents.

[0008] The present disclosure has been made in view of the above, and has an object to provide a copolymer having excellent dispersibility and sufficient solubility in water.

[0009] As a result of intensive research to achieve the above object, the inventors have found that the above object can be achieved by using a copolymer obtained by polymerizing a monomer having a hydrophilic group (excluding a catechol group) with a monomer having a catechol group. The present disclosure has been completed as a result of further research by the inventors.

[0010] The present disclosure encompasses, for example, the following subject matter: Item 1. A copolymer containing a structural unit (A) derived from a monomer (a) having a hydrophilic group (excluding a catechol group) and a structural unit (B) derived from a monomer (b) having a catechol group, wherein the hydrophilic group is a hydroxy group and / or a phosphate group, and wherein the copolymer has a weight average molecular weight of 500 or more and 20,000 or less.

[0011] According to the present disclosure, it is possible to provide a copolymer having excellent dispersibility and sufficient solubility in water. Because of such excellent properties, the copolymer of the present disclosure can be suitably used in a wide range of applications, such as dispersants, coating agents, paints, lubricating coatings, and batteries.

[0012] Preferred embodiments of the present disclosure will be described in detail below. The following description of the components may be based on representative embodiments and specific examples, but the present disclosure is not limited to such embodiments.

[0013] In the present disclosure, the expressions "contain" and "comprise" include the concepts of "contain," "include," "consist essentially of," and "consist only of."

[0014] In the numerical ranges described in stages in the present disclosure, the upper or lower limit of a certain numerical range can be arbitrarily combined with the upper or lower limit of another numerical range. In addition, in the numerical ranges described in the present disclosure, the upper or lower limit of the numerical range may be replaced with a value shown in an example or a value that can be unambiguously derived from an example.

[0015] In the present disclosure, "A and / or B" means "one of A and B" or "both A and B," and specifically means "A," "B," or "A and B."

[0016] In this disclosure, "n-" means "normal," "sec-" means secondary, and "tert-" means "tertiary."

[0017] In this disclosure, "(meth)acrylic" means acrylic or methacrylic, "(meth)acrylate" means acrylate or methacrylate, and "(meth)acryloyl" means acryloyl or methacryloyl.

[0018] In this disclosure, room temperature means a temperature within the range of 20°C to 25°C.

[0019] In the present disclosure, the "main chain of a monomer" refers to a carbon chain containing a polymerizable double bond (carbon-carbon double bond). In the present disclosure, the side chain of a monomer refers to a chain that is bonded to the main chain of a monomer and has a chain length shorter than that of the main chain.

[0020] In the present disclosure, the content of the structural unit (A) in all structural units of the copolymer can be considered to be equal to the amount of monomer (a) used relative to the total amount of monomers used in producing the copolymer.

[0021] In the present disclosure, the content of the structural unit (B) in all structural units of the copolymer can be considered to be equal to the amount of monomer (b) used relative to the total amount of monomers used in producing the copolymer.

[0022] In the monomer (a) represented by formula (1) and the monomer (b) represented by formula (2) of the present disclosure, examples of the linear or branched alkyl group having 1 to 20 carbon atoms (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, an ethyl ... Examples thereof include a tert-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a cyclopentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, an n-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, an n-heptadecyl group, an n-octadecyl group, an n-nonadecyl group, and an n-icosyl group.

[0023] In the monomer (a) represented by formula (1) and the monomer (b) represented by formula (2) of the present disclosure, examples of the linear or branched alkylene group having 1 to 10 carbon atoms (1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms) include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an n-butylene group, an isobutylene group, a sec-butylene group, a tert-butylene group, an n-pentylene group, an isopentylene group, a neopentylene group, a cyclopentylene group, an n-hexylene group, an n-heptylene group, an n-octylene group, an n-nonylene group, and an n-decylene group.

[0024] In the monomer (a) represented by formula (1) and the monomer (b) represented by formula (2) of the present disclosure, the linear or branched oxyalkylene group having 1 to 10 carbon atoms (1, 2, 3, 4, 5, 6, 7, 8, 9, or 10) is a group represented by -A-O-, where A is a linear or branched alkylene group having 1 to 10 carbon atoms (1, 2, 3, 4, 5, 6, 7, 8, 9, or 10).

[0025] In the monomer (a) represented by formula (1) and the monomer (b) represented by formula (2) of the present disclosure, the alkyl group having 1 to 3 (1, 2, or 3) carbon atoms is a methyl group, an ethyl group, an n-propyl group, or an isopropyl group.

[0026] In the monomer (a) represented by formula (1) and the monomer (b) represented by formula (2) of the present disclosure, the alkylene group having 1 to 3 (1, 2, or 3) carbon atoms is a methylene group, an ethylene group, an n-propylene group, or an isopropylene group.

[0027] In the monomer (a) represented by formula (1) and the monomer (b) represented by formula (2) of the present disclosure, the oxyalkylene group having 1 to 3 (1, 2 or 3) carbon atoms is —CH ２ —O—, —CH ２ -CH ２ —O—, —CH ２ -CH ２ -CH ２ —O— or —CH ２ -CH(CH ３ )-O-.

[0028] 1. Copolymer The copolymer of the present disclosure has the following constitutions (i), (ii), and (iii): (i) It contains a structural unit (A) derived from a monomer (a) having a hydrophilic group (excluding a catechol group) and a structural unit (B) derived from a monomer (b) having a catechol group. (ii) The hydrophilic group is a hydroxy group (—OH) and / or a phosphate group (—O—P(═O)(OH) ２ (iii) The mass average molecular weight is 500 or more and 20,000 or less.

[0029] The copolymer of the present disclosure has the above-described features (i), (ii), and (iii), and therefore has good hydrophilicity. In addition, the copolymer of the present disclosure has excellent dispersibility, and can be used as a dispersant.

[0030] In the above structure (ii), the hydroxy group does not include a hydroxy group contained in a carboxy group (—COOH).

[0031] In the above structure (ii), the number of hydroxy groups is preferably one or two, and the number of phosphate groups is preferably one.

[0032] Hereinafter, "monomer (a) having a hydrophilic group (excluding a catechol group)" may be simply referred to as "monomer (a)," and "monomer (b) having a catechol group" may be simply referred to as "monomer (b)."

[0033] In the present disclosure, the hydrophilic group contained in the monomer (a) does not include a catechol group. In the present disclosure, the hydrophilic group contained in the monomer (a) is preferably a hydroxy group or a phosphate group. In the present disclosure, the hydrophilic group contained in the monomer (a) is more preferably one or two hydroxy groups or one phosphate group.

[0034] In the present disclosure, from the viewpoint of achieving better hydrophilicity, the monomer (a) preferably has a hydrophilic group at the end of the side chain. In the present disclosure, when the monomer (a) has a hydrophilic group at the end of the side chain, the number of the hydrophilic groups is preferably 1 or 2. Here, the hydrophilic group at the "end of the side chain" refers to the hydrophilic group located farthest from the main chain of the monomer (a).

[0035] In the present disclosure, the monomer (a) usually has 1 to 4 radically polymerizable unsaturated groups, preferably 1 to 3 radically polymerizable unsaturated groups, more preferably 1 or 2 radically polymerizable unsaturated groups, and particularly preferably 1 radically polymerizable unsaturated group.

[0036] In one embodiment of the present disclosure, the monomer (a) preferably does not contain a terpene-based monomer or a conjugated diene-based monomer, and more preferably does not contain both a terpene-based monomer and a conjugated diene-based monomer.

[0037] In one embodiment of the present disclosure, the content of terpene monomer-derived structural units or conjugated diene monomer-derived structural units in the copolymer is preferably 5% by mass or less, more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less.

[0038] The radical polymerizable unsaturated group is preferably a group having a carbon-carbon double bond. Examples of the radical polymerizable unsaturated group include an acryloyl group (CH2=CH(CO)-), a methacryloyl group (CH ２ = CCH ３ (CO)-), styryl group (C ６ H ５ CH=CH-), allyl group (CH=CH-CH ２ -), etc. Among these, an acryloyl group or a methacryloyl group is preferred, and an acryloyl group is more preferred. These groups having a carbon-carbon double bond may further have a substituent, as long as the radical polymerizability is not inhibited. Examples of the substituent include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom).

[0039] In the present disclosure, the monomer (b) usually has 1 to 4 radically polymerizable unsaturated groups, preferably 1 to 3 radically polymerizable unsaturated groups, more preferably 1 or 2 radically polymerizable unsaturated groups, and particularly preferably 1 radically polymerizable unsaturated group.

[0040] The radical polymerizable unsaturated group is preferably a group having a carbon-carbon double bond. Examples of the radical polymerizable unsaturated group include an acryloyl group (CH2=CH(CO)-), a methacryloyl group (CH ２ = CCH ３ (CO)-), styryl group (C ６ H ５ CH=CH-), allyl group (CH=CH-CH ２ -), etc. Among these, an acryloyl group or a methacryloyl group is preferred, and a methacryloyl group is more preferred. These groups having a carbon-carbon double bond may further have a substituent, as long as the radical polymerizability is not inhibited. Examples of the substituent include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom).

[0041] The copolymer of the present disclosure has a mass average molecular weight of 500 or more and 20,000 or less. If the mass average molecular weight exceeds 20,000, the solubility in water decreases significantly. If the mass average molecular weight is less than 500, the copolymer may become a homopolymer of monomer (a) or a homopolymer of monomer (b). "Homopolymer of monomer (a)" means a polymer containing 100% by mass of the structural unit (A) derived from monomer (a). "Homopolymer of monomer (b)" means a polymer containing 100% by mass of the structural unit (B) derived from monomer (b).

[0042] The copolymer of the present disclosure has a mass average molecular weight of not less than 500 and not more than 20000. In a preferred embodiment of the present disclosure, the upper limit of the mass average molecular weight of the copolymer of the present disclosure may be 19000, 18000, 17000, 16000, 15000, 14000, or 13000, and the lower limit of the mass average molecular weight may be 750, 1000, 1250, 1500, 1750, 2000, 2250, 2500, 2750, 3000, or 3250, and these upper and lower limit values ​​can be combined in any manner.

[0043] The number average molecular weight (Mn) of the copolymer of the present disclosure is preferably 500 or more and 20,000 or less, and the upper limit of Mn may be 15,000, 12,500, 10,000, 9,500, 9,000, 8,750, 8,500, or 8,250, and the lower limit of Mn may be 750, 1,000, 1,250, 1,500, 1,750, or 2,000, and these upper and lower limit values ​​can be combined in any manner.

[0044] Specific methods for measuring the mass average molecular weight and Mn will be described in the examples below.

[0045] In one embodiment of the present disclosure, the total content of the structural unit (A) derived from monomer (a) and the structural unit (B) derived from monomer (b) relative to the total (100% by mass) of all structural units in the copolymer is more than 50% by mass, 55% by mass or more, 60% by mass or more, 65% by mass or more, 70% by mass or more, 75% by mass or more, 80% by mass or more, 83% by mass or more, 85% by mass or more, 88% by mass or more, 90% by mass or more, 91% by mass or more, 91.5% by mass or more, 92% by mass or more, 92.5% by mass or more, 93% by mass or more, 93.5% by mass or more, 94% by mass or more, 94.5% by mass or more, 95% by mass or more, 95.5% by mass or more, and 96% by mass or more are preferred, in this order.

[0046] As one embodiment of the present disclosure, the copolymer of the present disclosure is particularly preferably composed only of the structural unit (A) derived from the monomer (a) and the structural unit (B) derived from the monomer (b). However, even when the copolymer is composed only of the structural unit (A) derived from the monomer (a) and the structural unit (B) derived from the monomer (b), the inclusion of unavoidable impurities of the structural unit (A) derived from the monomer (a) and the structural unit (B) derived from the monomer (b) (for example, a trace amount of solvent remaining after purification during the production process of the copolymer) is permitted.

[0047] In the present disclosure, from the viewpoint of imparting better hydrophilicity to the copolymer, the content of the structural unit (B) derived from monomer (b) relative to the total molar amount (100 mol%) of the structural unit (A) derived from monomer (a) and the structural unit (B) derived from monomer (b) is preferably 1 mol% or more and 50 mol% or less, more preferably 1.5 mol% or more and 40 mol% or less, even more preferably 2 mol% or more and 30 mol% or less, and even more preferably 2.5 mol% or more and 25 mol% or less.

[0048] In a preferred embodiment of the present disclosure, the upper limit of the content of the structural unit (B) derived from monomer (b) relative to the total molar amount (100 mol%) of the structural unit (A) derived from monomer (a) and the structural unit (B) derived from monomer (b) is 50 mol%, 45 mol%, 40 mol%, 35 mol%, 30 mol%, 29 mol%, 28 mol%, 27 mol%, 26 mol%, 25 mol%, 24 mol%, 23 mol%, 22 mol%, and 21 mol%. %, and the lower limit of the content of the structural unit (B) derived from the monomer (b) can be 1 mol%, 1.5 mol%, 2 mol%, 2.5 mol%, 3 mol%, 3.5 mol%, 4 mol%, 4.5 mol%, 5 mol%, 5.5 mol%, 6 mol%, 6.5 mol%, 7 mol%, 7.5 mol%, 8 mol%, 8.5 mol%, 9 mol%, 9.5 mol%, or 10 mol%, and these upper and lower limit values ​​can be combined in any desired manner.

[0049] In the present disclosure, from the viewpoint of imparting better hydrophilicity to the copolymer, the content of the structural unit (A) derived from monomer (a) relative to the total molar amount (100 mol%) of the structural unit (A) derived from monomer (a) and the structural unit (B) derived from monomer (b) is preferably 50 mol% or more and 99 mol% or less, more preferably 60 mol% or more and 98.5 mol% or less, even more preferably 70 mol% or more and 98 mol% or less, and even more preferably 75 mol% or more and 97.5 mol% or less.

[0050] In a preferred embodiment of the present disclosure, the upper limit of the content of the structural unit (A) derived from monomer (a) relative to the total molar amount (100 mol%) of the structural unit (A) derived from monomer (a) and the structural unit (B) derived from monomer (b) can be 99 mol%, 98.5 mol%, 98 mol%, 97.5 mol%, 97 mol%, 96 mol%, 95 mol%, 94.5 mol%, 94 mol%, 93.5 mol%, 93 mol%, 92.5 mol%, 92 mol%, 91.5 mol%, 91 mol%, 90.5 mol%, and 90 mol%, and the lower limit of the content of the structural unit (A) derived from monomer (a) can be 50 mol%, 55 mol%, 60 mol%, 65 mol%, 70 mol%, 71 mol%, 72 mol%, 73 mol%, 74 mol%, and 75 mol%, and these upper and lower limits can be combined in any way.

[0051] In the present disclosure, from the viewpoint of providing the copolymer with better hydrophilicity, the content of the structural unit (A) derived from the monomer (a) relative to the total (100% by mass) of all structural units in the copolymer is preferably 55% by mass or more and 99% by mass or less, more preferably 60% by mass or more and 98% by mass or less, even more preferably 65% ​​by mass or more and 97% by mass or less, still more preferably 70% by mass or more and 96% by mass or less, and particularly preferably 75% by mass or more and 95.5% by mass or less.

[0052] In a preferred embodiment of the present disclosure, the upper limit of the content of the structural unit (A) derived from monomer (a) relative to the total (100% by mass) of all structural units in the copolymer can be 99.5% by mass, 99% by mass, 98.5% by mass, 98% by mass, 97.5% by mass, 97% by mass, 96.5% by mass, 96% by mass, or 95.5% by mass; the lower limit of the content of the structural unit (A) derived from monomer (a) can be 55% by mass, 60% by mass, 65% by mass, 70% by mass, 75% by mass, or 80% by mass; and these upper and lower limits can be combined in any manner.

[0053] In the present disclosure, the content of the structural unit (B) derived from the monomer (b) relative to the total (100% by mass) of all structural units in the copolymer is, from the viewpoint of providing the copolymer with better hydrophilicity, preferably 0.5% by mass or more and 45% by mass or less, more preferably 0.75% by mass or more and 40% by mass or less, even more preferably 1.0% by mass or more and 35% by mass or less, even more preferably 1.1% by mass or more and 30% by mass or less, and particularly preferably 1.2% by mass or more and 20% by mass or less.

[0054] In a preferred embodiment of the present disclosure, the upper limit of the content of the structural unit (B) derived from monomer (b) relative to the total (100% by mass) of all structural units in the copolymer can be 45% by mass, 40% by mass, 35% by mass, 30% by mass, 28% by mass, 26% by mass, 24% by mass, 22% by mass, or 20% by mass; the lower limit of the content of the structural unit (B) derived from monomer (b) can be 0.5% by mass, 0.75% by mass, 1.0% by mass, 1.1% by mass, 1.2% by mass, 1.5% by mass, 2% by mass, 2.5% by mass, 2.6% by mass, 2.8% by mass, 3% by mass, 3.2% by mass, or 3.4% by mass; and these upper and lower limits can be combined in any manner.

[0055] The copolymer of the present disclosure is preferably water-soluble. In the present disclosure, a water-soluble copolymer means a copolymer that is evaluated as "good" (transparent and completely dissolved) in the <Solubility Evaluation Method> described in the Examples below.

[0056] In one embodiment of the present disclosure, the copolymer of the present disclosure preferably contains elemental sulfur. When the copolymer contains elemental sulfur, the content of elemental sulfur in the copolymer is usually more than 0 mg / kg and not more than 20,000 mg / kg, preferably 50 mg / kg or more and not more than 18,000 mg / kg, more preferably 100 mg / kg or more and not more than 16,000 mg / kg, even more preferably 500 mg / kg or more and not more than 10,000 mg / kg, and still more preferably 1,000 mg / kg or more and not more than 5,000 mg / kg.

[0057] The content of sulfur element in the copolymer can be measured, for example, by a "multi-type ICP optical emission spectrometer" manufactured by Shimadzu Corporation. A specific method for measuring the content of sulfur element in the copolymer will be described in the examples below.

[0058] In the present disclosure, the monomer (a) is preferably a monomer represented by the following formula (1): (In formula (1), R １ represents a hydrogen atom or a linear or branched alkyl group having 1 to 20 carbon atoms (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20). X represents an amide bond (-C(O)NH- or -NHC(O)-) or an ester bond (-C(O)O- or -OC(O)-). R ２ represents a single bond, a linear or branched alkylene group having 1 to 10 carbon atoms (1, 2, 3, 4, 5, 6, 7, 8, 9, or 10) which may have a substituent, or a linear or branched oxyalkylene group having 1 to 10 carbon atoms (1, 2, 3, 4, 5, 6, 7, 8, 9, or 10) which may have a substituent. n represents a number of 1 or more and 20 or less on average. R ２ is a single bond or a linear or branched alkylene group having 1 to 10 (1, 2, 3, 4, 5, 6, 7, 8, 9, or 10) carbon atoms which may have a substituent, R ３ represents a hydroxy group or a phosphate group. ２ is a linear or branched oxyalkylene group having 1 to 10 (1, 2, 3, 4, 5, 6, 7, 8, 9, or 10) carbon atoms which may have a substituent, R ３ represents a hydrogen atom, a hydroxy group, or a phosphate group.

[0059] In the above formula (1), R １ is preferably a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms (1, 2, 3, 4, 5, 6, 7, 8, 9, or 10).

[0060] In the above formula (1), R １is more preferably a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms (1, 2, 3, 4, 5, or 6).

[0061] In the above formula (1), R １ is even more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms (1, 2 or 3) (methyl group, ethyl group, n-propyl group or isopropyl group).

[0062] In the above formula (1), R １ is particularly preferably a hydrogen atom or a methyl group.

[0063] In the above formula (1), R １ is most preferably a hydrogen atom.

[0064] In the above formula (1), X is preferably an ester bond.

[0065] In the above formula (1), R ２ is preferably a linear or branched alkylene group having 1 to 6 (1, 2, 3, 4, 5, or 6) carbon atoms which may have a substituent, or a linear or branched oxyalkylene group having 1 to 6 (1, 2, 3, 4, 5, or 6) carbon atoms which may have a substituent.

[0066] As a more preferred embodiment of the present disclosure, in the above formula (1), R １ represents a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms (1, 2, 3, 4, 5, or 6), and X represents an ester bond; R ２ represents a linear or branched alkylene group having 1 to 6 (1, 2, 3, 4, 5, or 6) carbon atoms which may have a substituent, n represents an average number of 2 or more and 18 or less, and R ３ represents a hydroxy group or a phosphate group; or R ２ represents a linear or branched oxyalkylene group having 1 to 6 (1, 2, 3, 4, 5, or 6) carbon atoms which may have a substituent, n represents an average value of 2 or more and 18 or less, and R ３ indicates a hydrogen atom.

[0067] In the above formula (1), R ２is more preferably an alkylene group having 1 to 3 (1, 2 or 3) carbon atoms which may have a substituent, or an oxyalkylene group having 1 to 3 (1, 2 or 3) carbon atoms which may have a substituent.

[0068] As a more preferred embodiment of the present disclosure, in the above formula (1), R １ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms (1, 2 or 3), and X represents an ester bond; R ２ represents an alkylene group having 1 to 3 (1, 2 or 3) carbon atoms which may have a substituent, n represents an average value of 2.5 or more and 16 or less, and R ３ represents a hydroxy group or a phosphate group; or R ２ represents an oxyalkylene group having 1 to 3 (1, 2 or 3) carbon atoms which may have a substituent, n represents an average value of 2.5 or more and 16 or less, and R ３ indicates a hydrogen atom.

[0069] As a particularly preferred embodiment of the present disclosure, in the above formula (1), R １ represents a hydrogen atom or a methyl group, and X represents an ester bond; R ２ represents an alkylene group having 1 to 3 (1, 2 or 3) carbon atoms which may have a substituent, n represents an average number of 3 or more and 14 or less, and R ３ represents a hydroxy group or a phosphate group; or R ２ represents an oxyalkylene group having 1 to 3 (1, 2 or 3) carbon atoms which may have a substituent, n represents an average number of 3 or more and 14 or less, and R ３ indicates a hydrogen atom.

[0070] As the most preferred embodiment of the present disclosure, in the above formula (1), R １ represents a hydrogen atom or a methyl group, and X represents an ester bond; R ２ represents an alkylene group having 1 to 3 (1, 2 or 3) carbon atoms, n represents an average value of 3.5 or more and 12 or less, and R ３ represents a hydroxy group or a phosphate group; or R ２represents an oxyalkylene group having 1 to 3 (1, 2 or 3) carbon atoms which may have one hydroxy group, n represents an average value of 3.5 or more and 12 or less, and R ３ indicates a hydrogen atom.

[0071] In the above formula (1), n ​​is the number of repetitions, and is an average value of 1 to 20. The value of n can be measured by nuclear magnetic resonance analysis (NMR). Specifically, the value of n can be calculated by measuring the integrated value from 3 ppm to 4 ppm.

[0072] As a preferred embodiment of the present disclosure, in the above formula (1), the upper limit value of n can be 19, 18, 17, 16, 15, 14, 13, 12, 11, and 10, and the lower limit value of n can be 1.5, 2, 2.5, 3, 3.5, 4, and 4.5, and these upper and lower limit values ​​can be combined in any way.

[0073] As one embodiment of the present disclosure, in the above formula (1), n ​​preferably represents an average number of 2 or more and 18 or less, more preferably an average number of 2.5 or more and 16 or less, even more preferably an average number of 3 or more and 14 or less, even more preferably an average number of 3.5 or more and 12 or less, and particularly preferably an average number of 4 or more and 11 or less.

[0074] In the above formula (1), R ２ is a linear or branched oxyalkylene group having 1 to 10 (1, 2, 3, 4, 5, 6, 7, 8, 9, or 10) carbon atoms which may have a substituent, R ３ is preferably a hydrogen atom.

[0075] R in the above formula (1) ２ In the formula (I), the substituent is not particularly limited as long as it is other than a hydrogen atom, and examples thereof include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), a cyano group, a nitro group, a hydroxy group, an amino group, an ester group, a carboxy group, an epoxy group, a phosphate group, an isocyanate group, a phenyl group, etc. These substituents can be used either alone or in combination of two or more.

[0076] As an embodiment of the present disclosure, R in the above formula (1) ２ The number of substituents in is usually 1 to 4, preferably 1 or 2, and more preferably 1.

[0077] As an embodiment of the present disclosure, R in the above formula (1) ２ In the formula (I), the substituents are preferably 1 to 4 hydroxy groups, more preferably 1 or 2 hydroxy groups, and even more preferably 1 hydroxy group.

[0078] Monomer (a) represented by the above formula (1) is preferably at least one selected from the group consisting of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-methacryloyloxyethyl acid phosphate, 2-acryloyloxyethyl acid phosphate, hydroxyethyl acrylamide, N-methylolacrylamide, glycerin monomethacrylate, polyethylene glycol monoacrylate, polyethylene glycol monomethacrylate, polypropylene glycol monoacrylate, and polypropylene glycol monomethacrylate, more preferably at least one selected from the group consisting of 2-methacryloyloxyethyl acid phosphate, 2-acryloyloxyethyl acid phosphate, polyethylene glycol monoacrylate, polyethylene glycol monomethacrylate, polypropylene glycol monoacrylate, and polypropylene glycol monomethacrylate, even more preferably at least one selected from the group consisting of 2-methacryloyloxyethyl acid phosphate, 2-acryloyloxyethyl acid phosphate, polyethylene glycol monoacrylate, and polyethylene glycol monomethacrylate, Particularly preferred are 2-acryloyloxyethyl acid phosphate and / or polyethylene glycol monoacrylate.

[0079] A wide variety of known commercially available products can be used as the monomer (a) represented by the formula (1). Examples of commercially available products include "Blemmer AE-200," "Blemmer AE-400," "Blemmer GLM," "Blemmer GLM-EX," "Blemmer GLM-R," "Blemmer E," "Blemmer PE-90," "Blemmer PE-200," "Blemmer PE-350," "Blemmer AP-200," "Blemmer AP-400," "Blemmer AP-550," "Blemmer AP-800," "Blemmer AP-400D," "Blemmer AP-1000D," "Blemmer P," "Blemmer PP-1000," "Blemmer PP-500," and "Blemmer PP-800," all manufactured by NOF Corporation; and "Light Acrylate P-1A(N)" and "Light Ester P-1M," all manufactured by Kyoeisha Chemical Co., Ltd.

[0080] In the present disclosure, the monomer (b) is preferably a monomer represented by the following formula (2): (In the formula, R ４ represents a hydrogen atom or a linear or branched alkyl group having 1 to 20 carbon atoms (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20). Y represents an amide bond (-C(O)NH- or -NHC(O)-) or an ester bond (-C(O)O- or -OC(O)-). R ５ R represents a single bond or a linear or branched alkylene group having 1 to 10 (1, 2, 3, 4, 5, 6, 7, 8, 9, or 10) carbon atoms which may have a substituent. ６ represents a single bond, an ether bond (—O—), —CH(OH)—, an ester bond (—C(O)O— or —OC(O)—), or a carbonate group (—OC(O)O—).

[0081] In the above formula (2), R ４ is preferably a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms (1, 2, 3, 4, 5, 6, 7, 8, 9, or 10).

[0082] In the above formula (2), R ４is more preferably a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms (1, 2, 3, 4, 5, or 6).

[0083] In the above formula (2), R ４ It is even more preferred that is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms (1, 2 or 3).

[0084] In the above formula (2), R ４ is particularly preferably a hydrogen atom or a methyl group.

[0085] In the above formula (2), R ４ is most preferably a methyl group.

[0086] In the above formula (2), R ５ is preferably a linear or branched alkylene group having 1 to 6 (1, 2, 3, 4, 5 or 6) carbon atoms which may have a substituent, and more preferably an alkylene group having 1 to 3 (1, 2 or 3) carbon atoms which may have a substituent.

[0087] In the above formula (2), R ６ is preferably a single bond or an ester bond.

[0088] In one embodiment of the present disclosure, in the above formula (2), when Y is an amide bond, R ５ is preferably a linear or branched alkylene group having 1 to 6 (1, 2, 3, 4, 5 or 6) carbon atoms which may have a substituent, and more preferably a linear or branched alkylene group having 1 to 3 (1, 2 or 3) carbon atoms which may have a substituent.

[0089] In one embodiment of the present disclosure, in the above formula (2), Y is an amide bond and R ６ is a single bond, R ５ is preferably a linear or branched alkylene group having 1 to 6 (1, 2, 3, 4, 5 or 6) carbon atoms which may have a substituent, and more preferably an alkylene group having 1 to 3 (1, 2 or 3) carbon atoms which may have a substituent.

[0090] As an embodiment of the present disclosure, in the above formula (2), when Y is an ester bond, R ５is preferably a linear or branched alkylene group having 1 to 6 (1, 2, 3, 4, 5 or 6) carbon atoms which may have a substituent, more preferably an alkylene group having 1 to 3 (1, 2 or 3) carbon atoms which may have a substituent, even more preferably an alkylene group having 1 to 3 (1, 2 or 3) carbon atoms which has a hydroxy group, still more preferably an alkylene group having 1 to 3 (1, 2 or 3) carbon atoms which has one hydroxy group, and particularly preferably an n-propylene group which has one hydroxy group.

[0091] As an embodiment of the present disclosure, in the above formula (2), Y and R ６ When both of R ５ is preferably a linear or branched alkylene group having 1 to 6 (1, 2, 3, 4, 5 or 6) carbon atoms which may have a substituent, more preferably an alkylene group having 1 to 3 (1, 2 or 3) carbon atoms which may have a substituent, even more preferably an alkylene group having 1 to 3 (1, 2 or 3) carbon atoms which has a hydroxy group, still more preferably an alkylene group having 1 to 3 (1, 2 or 3) carbon atoms which has one hydroxy group, and particularly preferably an n-propylene group which has one hydroxy group.

[0092] R in the above formula (2) ５ In the formula (2), examples of the substituent include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), a cyano group, a nitro group, a hydroxy group, an amino group, an ester group, a carboxy group, an epoxy group, a phosphate group, an isocyanate group, and a phenyl group. These substituents can be used alone or in combination of two or more. Among these substituents, a hydroxy group is preferred. R in the formula (2) ５ The number of substituents in is usually 1 to 4, preferably 1 or 2, and more preferably 1.

[0093] As an embodiment of the present disclosure, R in the above formula (2) ５ In the formula (I), the substituents are preferably 1 to 4 hydroxy groups, more preferably 1 or 2 hydroxy groups, and even more preferably 1 hydroxy group.

[0094] As a preferred embodiment of the present disclosure, in the above formula (2), R ４ represents a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms (1, 2, 3, 4, 5, or 6), and Y represents an amide bond or an ester bond; when Y is an amide bond, R ５ represents a linear or branched alkylene group having 1 to 6 (1, 2, 3, 4, 5, or 6) carbon atoms which may have a substituent, and R ６ represents a single bond; or when Y is an ester bond, R ５ represents a linear or branched alkylene group having 1 to 6 (1, 2, 3, 4, 5, or 6) carbon atoms which may have a substituent, and R ６ indicates an ester bond.

[0095] As a more preferred embodiment of the present disclosure, in the above formula (2), R ４ represents a hydrogen atom or an alkylene group having 1 to 3 carbon atoms (1, 2, or 3), and Y represents an amide bond or an ester bond; when Y is an amide bond, R ５ represents an alkylene group having 1 to 3 (1, 2 or 3) carbon atoms which may have a substituent, and R ６ represents a single bond; or when Y is an ester bond, R ５ represents an alkylene group having 1 to 3 (1, 2 or 3) carbon atoms which may have a substituent, and R ６ indicates an ester bond.

[0096] As a more preferred embodiment of the present disclosure, in the above formula (2), R ４ represents a hydrogen atom or a methyl group, and Y represents an amide bond or an ester bond; when Y is an amide bond, R ５ represents an alkylene group having 1 to 3 (1, 2 or 3) carbon atoms which may have a substituent, and R ６ represents a single bond; or when Y is an ester bond, R ５ represents an alkylene group having 1 to 3 (1, 2 or 3) carbon atoms and one hydroxy group, and R ６ indicates an ester bond.

[0097] As a particularly preferred embodiment of the present disclosure, in the above formula (2), R ４ represents a methyl group, and Y represents an amide bond or an ester bond; when Y is an amide bond, R ５ represents an alkylene group having 1 to 3 (1, 2 or 3) carbon atoms which may have a substituent, and R ６ represents a single bond; or when Y is an ester bond, R ５ represents an alkylene group having 1 to 3 (1, 2 or 3) carbon atoms and one hydroxy group, and R ６ indicates an ester bond.

[0098] When Y is an amide bond, the monomer (b) represented by the above formula (2) is preferably N-[2-(3,4-dihydroxyphenyl)methyl](meth)acrylamide, N-[2-(3,4-dihydroxyphenyl)ethyl](meth)acrylamide [also known as dopamine methacrylamide (DMA)], N-[2-(3,4-dihydroxyphenyl)propyl](meth)acrylamide, N-[2-(3,4-dihydroxyphenyl)butyl](meth)acrylamide, N-[2-(3,4-dihydroxyphenyl)pentyl](meth)acrylamide, N-[2-(3,4-dihydroxyphenyl)hexyl](meth)acrylamide, N-[2-(3,4-dihydroxyphenyl)heptyl](meth)acrylamide, N-[2-(3,4-dihydroxyphenyl)octyl](meth)acrylamide, The compound is at least one selected from the group consisting of N-[2-(3,4-dihydroxyphenyl)nonyl](meth)acrylamide and N-[2-(3,4-dihydroxyphenyl)decyl](meth)acrylamide.

[0099] When Y is an ester bond, the monomer (b) represented by the above formula (2) is preferably N-[2-(3,4-dihydroxyphenyl)methyl](meth)acrylate, N-[2-(3,4-dihydroxyphenyl)ethyl](meth)acrylate, N-[2-(3,4-dihydroxyphenyl)propyl](meth)acrylate, N-[2-(3,4-dihydroxyphenyl)butyl](meth)acrylate, N-[2-(3,4-dihydroxyphenyl)pentyl](meth)acrylate, N-[2-(3,4-dihydroxyphenyl)hexyl](meth)acrylate, N-[2-(3,4-dihydroxyphenyl)heptyl](meth)acrylate, N-[2-(3,4-dihydroxyphenyl)octyl](meth)acrylate, N-[2-(3,4-dihydroxyphenyl)nonyl](meth)acrylate, and The compound is at least one selected from the group consisting of N-[2-(3,4-dihydroxyphenyl)decyl](meth)acrylate.

[0100] As the monomer (b) represented by the formula (2), a wide variety of known commercially available products can be used, such as "dopamine methacrylamide (DMA)" manufactured by Tokyo Chemical Industry Co., Ltd.

[0101] In the copolymer of the present disclosure, the arrangement of the structural units (A) derived from the monomer (a) and the arrangement of the structural units (B) derived from the monomer (b) may each be random, block, graft, or gradient.

[0102] The copolymer of the present disclosure may further contain a structural unit other than the structural unit (A) derived from the monomer (a) and the structural unit (B) derived from the monomer (b). Examples of the structural unit other than the structural unit (A) and the structural unit (B) include a structural unit derived from a chain transfer agent and a structural unit derived from a polymerization initiator.

[0103] In one embodiment of the present disclosure, the content of structural units other than the structural unit (A) derived from monomer (a) and the structural unit (B) derived from monomer (b) in all structural units of the copolymer of the present disclosure is preferably 20% by mass or less, 17% by mass or less, 15% by mass or less, 12% by mass or less, 10% by mass or less, 9% by mass or less, 8.5% by mass or less, 7.5% by mass or less, 5% by mass or less, and 4% by mass or less, in that order.

[0104] 2. Method for Producing Copolymer The method for producing a copolymer according to the present disclosure includes copolymerizing a monomer (a) having a hydrophilic group (excluding a catechol group) and a monomer (b) having a catechol group in the presence of a chain transfer agent. By adopting such a configuration, the production method according to the present disclosure can easily produce a copolymer having excellent dispersibility and sufficient solubility in water.

[0105] The method for producing the copolymer of the present disclosure will be described in detail below. Hereinafter, the method for producing the copolymer of the present disclosure will also be referred to simply as the "production method of the present disclosure." In the production method of the present disclosure, the step of copolymerizing the monomer (a) and the monomer (b) in the presence of a chain transfer agent will also be referred to simply as the "copolymerization step."

[0106] Details of the copolymer produced by the production method of the present disclosure are as described above in "1. Copolymer" unless otherwise specified. Furthermore, details of the monomer (a) and the monomer (b) used in the production method of the present disclosure are as described above in "1. Copolymer" unless otherwise specified.

[0107] The method for copolymerizing the monomer (a) and the monomer (b) can be widely adopted, and examples thereof include emulsion polymerization, suspension polymerization, bulk polymerization, interfacial polymerization, solution polymerization, etc. Among these, solution polymerization is preferred.

[0108] As a method for copolymerizing the monomer (a) and the monomer (b), a wide variety of known methods can be adopted, and examples thereof include a method in which an organic solvent is added to a mixture containing the monomer (a) and the monomer (b) to prepare a monomer mixed liquid, and a polymerization initiator and a chain transfer agent are further added to the obtained monomer mixed liquid to copolymerize the monomer (a) and the monomer (b).

[0109] In the copolymerization step, examples of the chain transfer agent include 1-mercapto-1,1-methanediol, 1-mercapto-1,1-ethanediol, 3-mercapto-1,2-propanediol, 2-mercapto-1,2-propanediol, 2-mercapto-2-methyl-1,3-propanediol, 2-mercapto-2-ethyl-1,3-propanediol, 1-mercapto-2,2-propanediol, 2-mercaptoethyl-2-methyl-1,3-propanediol, 2-mercaptoethyl-2-ethyl-1,3-propanediol, octyl mercaptan, dodecyl mercaptan, and 3-mercaptopropionic acid.

[0110] In the copolymerization step, the amount of the chain transfer agent used is preferably 0.01 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the total of the monomer (a) and the monomer (b), from the viewpoint of efficiently proceeding with the polymerization.

[0111] As the polymerization initiator, a wide range of known azo compounds or organic peroxides commonly used in this field can be used.

[0112] Examples of the azo compounds include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), dimethyl 1,1'-azobis(1-cyclohexanecarboxylate), dimethyl 2,2'-azobis(2-methylpropionate), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-hydroxymethylpropionitrile), and 2,2'-azobis[2-(2-imidazolin-2-yl)propane].

[0113] Examples of the organic peroxides include benzoyl peroxide, t-butylperoxy 2-ethylhexaate, t-butylperbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di(2-ethoxyethyl)peroxydicarbonate, t-butylperoxyneodecanoate, t-butylperoxypivalate, (3,5,5-trimethylhexanoyl)peroxide, dipropionyl peroxide, and diacetyl peroxide.

[0114] From the viewpoint of efficiently proceeding with the polymerization, the amount of the polymerization initiator used is preferably 0.1 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the total of the monomer (a) and the monomer (b).

[0115] Examples of the organic solvent include ether compounds, alcohol compounds, amide compounds, ester compounds, ketone compounds, sulfoxide compounds, hydrocarbon compounds, etc. These organic solvents can be used either alone or in combination of two or more.

[0116] Examples of the ether compound include chain ethers such as diethyl ether, and cyclic ethers such as tetrahydrofuran (THF) and dioxane. These ether compounds can be used alone or in combination of two or more.

[0117] Examples of the alcohol compound include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutyl alcohol, sec-butyl alcohol, tert-butyl alcohol, etc. These alcohol compounds can be used either alone or in combination of two or more.

[0118] Examples of the amide compound include N,N-dimethylacetamide, N,N-dimethylformamide (DMF), etc. These amide compounds can be used either alone or in combination of two or more.

[0119] Examples of the ester compound include methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, 3-methoxybutyl acetate, methyl propionate, ethyl propionate, dimethyl carbonate, diethyl carbonate, ethyl lactate, etc. These ester compounds can be used either alone or in combination of two or more.

[0120] Examples of the ketone compound include acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl butyl ketone, cyclohexanone, isophorone, etc. These ketone compounds may be used alone or in combination of two or more.

[0121] Examples of the sulfoxide compound include dimethyl sulfoxide.

[0122] Examples of the hydrocarbon compound include aromatic hydrocarbons such as benzene, toluene, and xylene, aliphatic hydrocarbons such as hexane, and alicyclic hydrocarbons such as cyclohexane. These hydrocarbon compounds can be used either alone or in combination of two or more.

[0123] From the viewpoint of efficiently proceeding with the polymerization, the amount of the organic solvent used is preferably 100 parts by mass or more and 1000 parts by mass or less per 100 parts by mass of the total of the monomer (a) and the monomer (b).

[0124] In the copolymerization step, the polymerization reaction is usually carried out at a temperature ranging from 30° C. to 100° C., preferably from 40° C. to 80° C. The temperature during the polymerization reaction may be constant or may be changed during the polymerization reaction.

[0125] In the copolymerization step, the time for the polymerization reaction from the start to the end of the polymerization is usually 0.5 hours to 48 hours, preferably 1 hour to 30 hours.

[0126] 3. Applications of the Copolymer The copolymer of the present disclosure has excellent dispersibility and sufficient solubility in water, and therefore can be suitably used in a wide range of applications, such as dispersants, coating agents, paints, lubricating coatings, batteries, electrode materials, coating materials, plating, catalysts, etc. Details of the copolymer of the present disclosure are as described above in "1. Copolymer" unless otherwise specified.

[0127] Specific applications of dispersants containing the copolymer of the present disclosure include, for example, dispersants for inorganic pigments, dispersants for organic pigments, dispersants for inorganic particles, dispersants for organic particles, and dispersants for cells.

[0128] Examples of inorganic pigments that can be used as the inorganic pigment dispersant include white pigments such as titanium dioxide, zinc oxide, lithopone, precipitated calcium carbonate, white carbon, aluminum oxide, aluminum hydroxide, and barium sulfate; black pigments such as carbon black, titanium black, titanium carbon, iron oxide, and graphite; iron oxide, barium yellow, cadmium red, and chrome yellow.

[0129] Examples of organic pigments that can be used in the organic pigment dispersants include phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green; azo pigments such as azo red, azo yellow, and azo orange; quinacridone pigments such as quinacridone red, shinkasha red, and shinkasha magenta; perylene pigments such as perylene red and perylene maroon; diazo pigments; isoindolinone pigments; dioxazine pigments; perylene pigments; thioindigo pigments; anthraquinone pigments; and quinophthalone pigments.

[0130] Examples of inorganic particles that can be used in the inorganic particle dispersant include zinc oxide particles, silicon oxide (silica) particles, titanium oxide (titania) particles, zirconium oxide (zirconia) particles, magnesium oxide (magnesia) particles, aluminum oxide (alumina) particles, and cerium oxide (ceria) particles.

[0131] Examples of organic particles that can be used in the dispersant for organic particles include PTFE particles, hydrocarbon particles, polyethylene particles, polystyrene particles, polyvinylidene fluoride particles, polyvinyl alcohol particles, polyvinyl chloride particles, polyvinylidene chloride particles, polyethylene terephthalate particles, and nylon particles.

[0132] Examples of cells that can be used with the cell dispersing agent include mesenchymal stem cells; Chinese hamster ovary-derived CHO cells; mouse connective tissue L929 cells; human embryonic kidney-derived HEK293 cells; human cervical cancer-derived HeLa cells; epithelial cells or endothelial cells that constitute various tissues or organs in the body; skeletal muscle cells, smooth muscle cells, or cardiac muscle cells that exhibit contractility; neuronal cells, glial cells, or fibroblasts that constitute the nervous system; hepatic parenchymal cells, non-hepatic parenchymal cells, or adipocytes that are involved in the metabolism of the body; cells with differentiation potential (e.g., stem cells, etc.); cells induced to differentiate from cells with differentiation potential; cells contained in blood, lymph, cerebrospinal fluid, sputum, urine, or stool; and microorganisms, viruses, or protozoa that are present in the body or in the environment.

[0133] A dispersant containing the copolymer of the present disclosure can be suitably used as a dispersant for organic particles, and particularly suitably used as a dispersant for PTFE particles.

[0134] The content of the copolymer in the dispersant is usually more than 50% by mass, preferably 75% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, still more preferably 99% by mass or more, still more preferably 99.5% by mass or more, and particularly preferably 99.9% by mass or more. Most preferably, the dispersant consists of only the copolymer.

[0135] Specific applications of coating agents containing the copolymers of the present disclosure include, for example, coating agents for displays, coating agents for vehicles, coating agents for building materials, coating agents for printing, and coating agents for batteries.

[0136] Specific applications of paints containing the copolymer of the present disclosure include, for example, paints for building materials, paints for automobiles, paints for semiconductors, paints for industrial products, and paints for structures.

[0137] Lubricating coatings containing the copolymer of the present disclosure typically contain the copolymer of the present disclosure and a surface free energy of 70 mJ / m ２ The coating is made of particles smaller than 100 microns in size and a surfactant.

[0138] The lubricating coating containing the copolymer of the present disclosure preferably comprises a copolymer of the present disclosure and a lubricating agent having a surface free energy of 70 mJ / m ２ a coating comprising particles of less than 70 mJ / m and a surfactant, and ２ The particles of less than 1000 nm are at least one selected from the group consisting of PTFE particles, hydrocarbon particles, polyethylene particles, polystyrene particles, polyvinylidene fluoride particles, polyvinyl alcohol particles, polyvinyl chloride particles, polyvinylidene chloride particles, polyethylene terephthalate particles, nylon particles, zinc oxide particles, and carbon tubes (nanoparticles).

[0139] A particularly preferred lubricating coating containing the copolymer of the present disclosure is a coating consisting of the copolymer of the present disclosure, PTFE particles, and a surfactant.

[0140] Specific applications of batteries containing the copolymer of the present disclosure include, for example, nickel-metal hydride batteries, lithium ion secondary batteries, sodium ion secondary batteries, potassium ion secondary batteries, fuel cells, and the like.

[0141] As one embodiment of the present disclosure, a battery including the copolymer of the present disclosure preferably includes a positive electrode, a negative electrode, and an electrode film formed using a composite particle dispersion including the copolymer of the present disclosure.

[0142] As another embodiment of the present disclosure, a battery including the copolymer of the present disclosure preferably includes a positive electrode, a negative electrode, and a gas diffusion layer formed using a composite particle dispersion including the copolymer of the present disclosure.

[0143] 4. Composite Particles The composite particles of the present disclosure are made of a copolymer of the present disclosure and a polymer having a surface free energy of 70 mJ / m ２ and particles having a surface free energy of less than 70 mJ / m ２ The composite particles of the present disclosure have such a structure and can be dispersed in an aqueous solvent.

[0144] Details of the copolymer of the present disclosure are as described above in "1. Copolymer" unless otherwise specified.

[0145] In the composite particles of the present disclosure, the catechol group contained in the copolymer of the present disclosure has a surface free energy of 70 mJ / m ２ The copolymer of the present disclosure adheres to the surface of particles of less than 1000 kJ / cm2, and the hydrophilic groups contained in the copolymer of the present disclosure have a high affinity for aqueous solvents. The presence of hydrophilic groups on the surface of the composite particles of the present disclosure gives the composite particles of the present disclosure a high affinity for aqueous solvents, allowing the composite particles of the present disclosure to be dispersed in aqueous solvents. Therefore, the copolymer of the present disclosure can be suitably used as a dispersant in place of conventionally used fluorosurfactants.

[0146] The composite particles of the present disclosure are particles of a copolymer of the present disclosure and a polymer having a surface free energy of 70 mJ / m ２In the present disclosure, the term "composite" refers to particles having a surface free energy of 70 mJ / m or less. ２ This means that the catechol groups contained in the copolymer of the present disclosure are attached to the surfaces of particles of less than 1000 nm.

[0147] In the present disclosure, the surface free energy is 70 mJ / m ２ The mass ratio of the particles to the copolymer of the present disclosure (surface free energy is 70 mJ / m ２ The ratio of the mass of the particles of less than 100:100 to the mass of the copolymer of the present disclosure is preferably 100:30 to 100:0.5, more preferably 100:20 to 100:1.

[0148] In the present disclosure, the surface free energy in the composite particles is 70 mJ / m ２ The content of particles smaller than 1000 μm is preferably 70% by mass or more and 99% by mass or less.

[0149] In the present disclosure, the content of the copolymer of the present disclosure in the composite particles is preferably 1% by mass or more and 30% by mass or less.

[0150] Surface free energy is 70 mJ / m ２ The adhesion of the copolymer of the present disclosure to the particle surface of less than 70 mJ / m can be achieved, for example, by mixing the copolymer in an aqueous solvent and adding the copolymer to the particle surface. ２ This can be done by adding particles of less than 1000 kJ / g and stirring.

[0151] The aqueous solvent may be water, a water-soluble organic solvent, a mixture thereof, etc. Examples of water include natural water, purified water, distilled water, ion-exchanged water, and pure water.

[0152] Examples of the water-soluble organic solvent include alcohol compounds, ketone compounds, ether compounds, amide compounds, sulfoxide compounds, ester compounds, glycol compounds, etc. These water-soluble organic solvents can be used either alone or in combination of two or more.

[0153] Examples of the alcohol compound include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutyl alcohol, sec-butyl alcohol, tert-butyl alcohol, etc. These alcohol compounds can be used either alone or in combination of two or more.

[0154] Examples of the ketone compound include acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl butyl ketone, cyclohexanone, isophorone, etc. These ketone compounds may be used alone or in combination of two or more.

[0155] Examples of the ether compound include diethyl ether, tetrahydrofuran (THF), dioxane, etc. These ether compounds may be used either alone or in combination of two or more.

[0156] Examples of the amide compound include N,N-dimethylformamide (DMF), N,N-dimethylacetamide, etc. These amide compounds can be used either alone or in combination of two or more.

[0157] Examples of the sulfoxide compounds include dimethyl sulfoxide (DMSO).

[0158] Examples of the ester compound include methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, 3-methoxybutyl acetate, methyl propionate, ethyl propionate, dimethyl carbonate, diethyl carbonate, ethyl lactate, etc. These ester compounds can be used either alone or in combination of two or more.

[0159] Examples of the glycol compound include ethylene glycol, diethylene glycol, propylene glycol, propylene glycol monomethyl ether, propylene glycol monobutyl ether, and propylene glycol methyl ether acetate. These glycol compounds can be used alone or in combination of two or more.

[0160] In one embodiment of the present disclosure, the composite particles of the present disclosure preferably have a surface free energy of 70 mJ / m in order to have even better dispersibility. ２ At least a portion of the surface of a particle having a surface free energy of less than 70 mJ / m ２ The entire surface of the particles of less than 100 microns is coated with the copolymer of the present disclosure.

[0161] The composite particles of the present disclosure further contain a surfactant, and the surfactant has a surface free energy of 70 mJ / m ２ It is preferable that the particles adhere to the surface of the particles in an amount of less than 1000. The composite particles of the present disclosure have such a structure, and can be dispersed well in an aqueous solvent.

[0162] When the composite particles of the present disclosure contain a surfactant, the content of the surfactant in the composite particles is preferably 1% by mass or more and 20% by mass or less, in order to enable good dispersion in an aqueous solvent.

[0163] As the surfactant, a wide range of known surfactants commonly used in this field (excluding fluorine-based surfactants) can be used. Examples of surfactants include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. Among these, nonionic surfactants are preferred because they allow the composite particles to be well dispersed in an aqueous solvent. These surfactants can be used alone or in combination of two or more.

[0164] Examples of the anionic surfactant include sulfate salts such as alkali metal salts of higher fatty acids; sulfonates such as alkylbenzene sulfonates, alkyl sulfonates, and paraffin sulfonates; and phosphate salts such as higher alcohol phosphate salts. These anionic surfactants can be used either alone or in combination of two or more.

[0165] Examples of the cationic surfactant include quaternary ammonium salts such as alkyltrimethylammonium salts.

[0166] Examples of the amphoteric surfactant include amino acid-type amphoteric surfactants such as higher alkylaminopropionates; and betaine-type amphoteric surfactants such as higher alkyldimethylbetaine and higher alkyldihydroxyethylbetaine. These amphoteric surfactants can be used either alone or in combination of two or more.

[0167] Examples of the nonionic surfactant include polyoxyethylene alkyl ethers, polyoxyethylene phenyl ethers, polyoxyethylene alkyl esters, propylene glycol-propylene oxide copolymers, perfluoroalkylethylene oxide adducts, and 2-ethylhexanol ethylene oxide adducts. These nonionic surfactants can be used either alone or in combination of two or more.

[0168] As the surfactant, a wide variety of known commercially available products can be used, including, for example, "Noigen TDS-80" and "Noigen XL-80" manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.

[0169] In the composite particles of the present disclosure, the surface free energy is 70 mJ / m ２ The surface free energy of the particles is preferably less than 50 mJ / m ２ Less than or equal to 45 mJ / m ２ More preferably, 40 mJ / m or less ２ More preferably, 36 J / m or less ２ The following is the result.

[0170] In the composite particles of the present disclosure, the surface free energy is 70 mJ / m ２ Preferably, particles smaller than 18 mJ / m are PTFE particles (surface free energy = 18 mJ / m ２ ), hydrocarbon particles (surface free energy = 22 mJ / m ２ ), polyethylene particles (surface free energy = 31 mJ / m ２ ), polystyrene particles (surface free energy = 33 mJ / m ２ ), polyvinylidene fluoride particles (surface free energy = 33 mJ / m ２ ), polyvinyl alcohol particles (surface free energy = 37 mJ / m ２ ), polyvinyl chloride particles (surface free energy = 39 mJ / m ２ ), polyvinyl chloride particles (surface free energy = 40 mJ / m ２ ), polyethylene terephthalate particles (surface free energy = 43 mJ / m ２ ), nylon particles (surface free energy = 46 mJ / m ２ ), zinc oxide particles (surface free energy = 30.6 to 35.8 mJ / m ２ ) and carbon tubes (nanoparticles) (surface free energy = 40 mJ / m ２ 70mJ / m or more ２ At least one type of particle is selected from the group consisting of:

[0171] In the composite particles of the present disclosure, the surface free energy is 70 mJ / m ２ For particles smaller than this size, PTFE particles or carbon tubes (nanoparticles) are preferred, with PTFE particles being particularly preferred, since they can be easily dispersed in aqueous solvents.

[0172] In the composite particles of the present disclosure, the surface free energy is 70 mJ / m ２ The primary particle diameter of the particles of less than 1000 nm is preferably 10 nm or more and 1000 nm or less. The primary particle diameter can be measured, for example, by a particle size measuring device ("Zetasizer Nano ZS" manufactured by Malvern Panalytical).

[0173] In the composite particles of the present disclosure, the surface free energy is 70 mJ / m２ As the particles of less than 1000 nm, a wide variety of known commercially available products can be used, including, for example, "Dyneon TF9202Z" manufactured by 3M Japan Ltd. and "Lubron L-5" manufactured by Daikin Industries, Ltd.

[0174] 5. Composite Particle Dispersion The composite particle dispersion of the present disclosure contains the composite particles of the present disclosure and an aqueous solvent, with the composite particles being dispersed in the aqueous solvent.

[0175] Details of the copolymer of the present disclosure are as described above in "1. Copolymer" unless otherwise specified. Details of the composite particle of the present disclosure are as described above in "4. Composite particle" unless otherwise specified.

[0176] The composite particles of the present disclosure can be dispersed in an aqueous solvent by adding the composite particles of the present disclosure to an aqueous solvent and stirring the mixture.

[0177] The aqueous solvent may be water, a water-soluble organic solvent, a mixture thereof, etc. Examples of water include natural water, purified water, distilled water, ion-exchanged water, and pure water.

[0178] Examples of the water-soluble organic solvent include alcohol compounds, ketone compounds, ether compounds, amide compounds, sulfoxide compounds, ester compounds, glycol compounds, etc. These water-soluble organic solvents can be used either alone or in combination of two or more.

[0179] Examples of the alcohol compound include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutyl alcohol, sec-butyl alcohol, and tert-butyl alcohol. These alcohol compounds can be used alone or in combination of two or more.

[0180] Examples of the ketone compound include acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl butyl ketone, cyclohexanone, isophorone, etc. These ketone compounds may be used alone or in combination of two or more.

[0181] Examples of the ether compound include diethyl ether, tetrahydrofuran (THF), dioxane, etc. These ether compounds may be used alone or in combination of two or more.

[0182] Examples of the amide compound include N,N-dimethylformamide (DMF), N,N-dimethylacetamide, etc. These amide compounds can be used either alone or in combination of two or more.

[0183] Examples of the sulfoxide compounds include dimethyl sulfoxide (DMSO).

[0184] Examples of the ester compound include methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, 3-methoxybutyl acetate, methyl propionate, ethyl propionate, dimethyl carbonate, diethyl carbonate, ethyl lactate, etc. These ester compounds can be used either alone or in combination of two or more.

[0185] Examples of the glycol compound include ethylene glycol, diethylene glycol, propylene glycol, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol methyl ether acetate, etc. These glycol compounds can be used alone or in combination of two or more.

[0186] In the present disclosure, the content of the composite particles of the present disclosure in the composite particle dispersion is preferably 1% by mass or more and 70% by mass or less.

[0187] The present disclosure provides the following aspects of the invention: Item 1. A copolymer containing a structural unit (A) derived from a monomer (a) having a hydrophilic group (excluding a catechol group) and a structural unit (B) derived from a monomer (b) having a catechol group, wherein the hydrophilic group is a hydroxy group and / or a phosphate group, and the copolymer has a mass average molecular weight of 500 or more and 20,000 or less. Item 2. The copolymer according to Item 1, wherein the monomer (a) is a monomer represented by the following formula (1): (In the formula, R １ represents a hydrogen atom or a linear or branched alkyl group having 1 to 20 carbon atoms. X represents an amide bond (-C(O)NH- or -NHC(O)-) or an ester bond (-C(O)O- or -OC(O)-). R ２ represents a single bond, a linear or branched alkylene group having 1 to 10 carbon atoms which may have a substituent, or a linear or branched oxyalkylene group having 1 to 10 carbon atoms which may have a substituent. n represents an average number of 1 to 20. ２ is a single bond or a linear or branched alkylene group having 1 to 10 carbon atoms which may have a substituent, R ３ represents a hydroxy group or a phosphate group. ２ is a linear or branched oxyalkylene group having 1 to 10 carbon atoms which may have a substituent, R ３ represents a hydrogen atom, a hydroxy group, or a phosphate group. Item 3. The copolymer according to Item 1 or 2, wherein the monomer (b) is a monomer represented by the following formula (2): (In the formula, R ４ represents a hydrogen atom or a linear or branched alkyl group having 1 to 20 carbon atoms. Y represents an amide bond (-C(O)NH- or -NHC(O)-) or an ester bond (-C(O)O- or -OC(O)-). R ５ represents a single bond or a linear or branched alkylene group having 1 to 10 carbon atoms which may have a substituent. ６represents a single bond, an ether bond (—O—), —CH(OH)—, an ester bond (—C(O)O— or —OC(O)—), or a carbonate group (—OC(O)O—). Item 4. A copolymer according to any one of Items 1 to 3, and a surface free energy of 70 mJ / m ２ and a particle having a particle size of less than 100 μm, wherein the copolymer is adhered to the surface of the particle. Item 5. The composite particle according to Item 4, wherein the composite particle further comprises a surfactant, wherein the surfactant is adhered to the surface of the particle. Item 6. A composite particle dispersion comprising the composite particle according to Item 4 and an aqueous solvent, wherein the composite particle is dispersed in the aqueous solvent. Item 7. A composite particle dispersion comprising the composite particle according to Item 5 and an aqueous solvent, wherein the composite particle is dispersed in the aqueous solvent. Item 8. A method for producing the copolymer according to any one of Items 1 to 3, comprising a step of copolymerizing the monomer (a) and the monomer (b) in the presence of a chain transfer agent. Item 9. A dispersant comprising the copolymer according to any one of Items 1 to 3. Item 10. A coating agent comprising the copolymer according to any one of Items 1 to 3. Item 11. A paint comprising the copolymer according to any one of Items 1 to 3. Item 12. Item 13. A lubricating coating comprising the copolymer according to any one of Items 1 to 3. Item 14. A battery comprising the copolymer according to any one of Items 1 to 3.

[0188] The present disclosure will be described in more detail below based on examples, but the present disclosure is not limited to these examples. In the following examples and comparative examples, "room temperature" means a temperature within the range of 20°C to 25°C.

[0189] <Measurement methods and evaluation methods> The measurement methods and evaluation methods in the examples and comparative examples are as follows. In the measurement methods and evaluation methods, the copolymers obtained in each example and comparative example will be simply referred to as "copolymers." For the copolymer obtained in Example 2, the sulfur element content was also measured.

[0190] <Method for measuring mass average molecular weight and number average molecular weight (Mn)> The mass average molecular weight and number average molecular weight of the copolymer refer to the mass average molecular weight and number average molecular weight in terms of polystyrene (PS) measured using gel permeation chromatography (GPC). Specifically, the mass average molecular weight and number average molecular weight were measured as follows. The GPC measurement conditions for the copolymer were as follows. (Sample preparation) As a pretreatment, approximately 10 mg of copolymer was weighed into a 2 mL volumetric flask and the volume was adjusted to a constant volume with 2 mL of THF. After confirming that the copolymer was dissolved, the solution was filtered using a non-aqueous 0.45 μm syringe filter manufactured by Shimadzu GLC Corporation and then measured. (GPC measurement conditions) Apparatus = Shimadzu Corporation's "Prominence 20A" high-performance liquid chromatograph (GPC optional software) Guard column = Shimadzu Corporation's "Shim-pack GPC-800P" (4.6 mm I.D. x 10 mm) x 1 Column = Shimadzu Corporation's "Shim-pack GPC-801" (8 mm I.D. x 300 mm) x 2, "Shim-pack GPC-803" (8 mm I.D. x 300 mm) x 1, "Shim-pack GPC-804" (8 mm I.D. x 300 mm) x 1 Column temperature = 40°C Mobile phase = tetrahydrofuran (THF) Mobile phase flow rate = 1.0 mL / min Detector = RI Injection volume = 100 μL Measurement time = 45 minutes Sampling pitch = 500 msec Standard polystyrene samples for the calibration curve were "STANDARD SM-105" and "STANDARD SH-75" manufactured by Showa Denko K.K., with mass average molecular weights of 5,620,000, 3,120,000, 1,250,000, 442,000, 151,000, 53,500, 17,000, 7,660, 2,900, and 1,320. The polystyrene standards for the calibration curve were grouped into A [(I) 5,620,000, (II) 1,250,000, (III) 151,000, (IV) 17,000, (V) 2,900] and B [(VI) 3,120,000, (VII) 442,000, (VIII) 53,500, (IX) 7,660, (X) 1,320].Thereafter, A [(I) 2 mg, (II) 3 mg, (III) 4 mg, (IV) 4 mg, (V) 4 mg] was weighed out and dissolved in 30 mL of THF to prepare a solution of A. Next, B [(VI) 3 mg, (VII) 4 mg, (VIII) 4 mg, (IX) 4 mg, (X) 4 mg] was weighed out and dissolved in 30 mL of THF to prepare a solution of B. A standard polystyrene calibration curve was obtained by injecting 100 μL of each of the prepared solutions of A and B and creating a calibration curve (cubic equation) from the retention times obtained after measurement. The mass average molecular weight and number average molecular weight were calculated using the obtained calibration curve.

[0191] <Method for evaluating solubility> First, 8 g of ion-exchanged water and 0.08 g of copolymer were added to a glass container, and then the mixture was stirred at room temperature for 30 seconds using a vortex mixer ("Mixer N-61" manufactured by Nisshin Rika Co., Ltd.). After stirring, the mixture was visually inspected and the solubility was evaluated according to the following evaluation criteria. Note that if the mixture was rated as "△" or higher, it was deemed to be suitable for practical use. (Evaluation criteria) ○: Transparent and completely dissolved △: Cloudy and partially dissolved ×: Not dissolved

[0192] <Method for evaluating dispersibility> First, 0.10 g of a surfactant (polyoxyethylene tridecyl ether, "Noigen TDS-80" manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was dissolved in 27 g of ion-exchanged water in a glass container. Next, 0.7 g of polytetrafluoroethylene (PTFE) particles (primary particle diameter: 200 nm to 300 nm) ("Dyneon TF9202Z" manufactured by 3M Japan Ltd.) was added, and the mixture was stirred at 6000 rpm for 2 minutes at room temperature using a homogenizer ("Polytron PT10-35 GT" manufactured by KINEMATICA). Thereafter, 0.07 g of copolymer was added, and the mixture was stirred at 6000 rpm for 2 minutes at room temperature using a homogenizer to dissolve the copolymer. Next, an ultrasonic homogenizer ("SONIFIER 450" manufactured by Branson) was used to perform ultrasonic treatment at room temperature for 2 minutes to obtain a dispersion (solid content concentration of PTFE particles = 2.5% by mass). The average particle size of the obtained dispersion was measured using a particle size measuring device ("Zetasizer Nano ZS" manufactured by Malvern Panalytical) under the following measurement conditions. If the measured average particle size of the dispersion was in the range of 200 nm to 350 nm, the dispersion was evaluated as having been dispersed with a primary particle size. On the other hand, if the measured average particle size of the dispersion was greater than 350 nm, it was evaluated as having aggregated. (Measurement conditions for the average particle size of the dispersion) Cell: DTS0012 Temperature: 25°C Measurement time: 60 seconds The average particle size of the dispersion was calculated using data analysis software installed in the particle size measuring device.

[0193] <Method for Measuring Sulfur Element Content> The sulfur element content in the copolymer was measured as follows. Approximately 0.3 g of the copolymer was precisely weighed into a Teflon (registered trademark) container "XP1500Plus" designed specifically for microwave decomposition, and then evaporated to dryness while the temperature was raised stepwise on a hot plate from 100°C to 150°C to 200°C to 250°C. Next, 2 mL of hydrochloric acid (Ultrapur-100 ultra-high purity reagent, manufactured by Kanto Chemical Co., Ltd.) and 3 mL of nitric acid (Ultrapur-100 ultra-high purity reagent, manufactured by Kanto Chemical Co., Ltd.) were added, the mixture was allowed to stand for one hour, and microwave decomposition treatment was performed under the following decomposition conditions. After microwave decomposition, the insoluble matter was filtered through ADVANTEC No. 7 filter paper, washed with pure water, and the volume was adjusted to 25 mL. ICP emission spectroscopy was performed under the following measurement conditions to measure the sulfur element content (mg / kg) in the copolymer. If the range of the calibration curve was exceeded, further dilution was performed. (Microwave decomposition conditions) Decomposition apparatus = CEM "MARS5" microwave apparatus Container used = XP1500Plus container Decomposition conditions = stage 1 (output 400 W, power 100%, pressure 150 psi, heating time 10 min, temperature 120°C, holding time 15 min) stage 2 (output 400 W, power 100%, pressure 200 psi, heating time 10 min, temperature 150°C, holding time 15 min) stage 3 (output 400 W, power 100%, pressure 250 psi, heating time 10 min, temperature 180°C, holding time 15 min) stage 4 (output 400 W, power 100%, pressure 350 psi, heating time 15 min, temperature 205°C, holding time 20 min) (Measurement conditions for ICP optical emission spectroscopy) Measurement equipment = Shimadzu Corporation "ICPE-9000" multi-type ICP optical emission spectrometer Measurement element = sulfur element (182.037 nm) Observation direction = axial direction High frequency output = 1.20 kW Carrier flow rate = 0.7 L / min Plasma flow rate = 10.0 L / min Auxiliary flow rate = 0.6 L / min Exposure time = 30 seconds Standard solution for calibration curve = SPEX USA "XSTC-13" general-purpose mixed standard solution 31 elements mixed (base 5% HNO ３ ) - each about 10 mg / L, and SPEX "XSTC-8" general-purpose mixed standard solution 13 elements mixed (base H ２O / trace HF) - about 10 mg / L each The standard solution for the calibration curve was diluted with ultrapure water to prepare standard solutions of 5 ppm, 2.5 ppm, 1 ppm and 0.25 ppm for measurement.

[0194] Example 1 In a glass container, 2.57 g of polyethylene glycol monoacrylate (NOF Corporation, "Blenmer AE-200," n≈4.5, 272.3 g / mol) as monomer (a), 0.10 g of dopamine methacrylamide (DMA) (Tokyo Chemical Industry Co., Ltd., 221.3 g / mol) as monomer (b), 0.027 g of 3-mercapto-1,2-propanediol (Asahi Chemical Industry Co., Ltd., "1-thioglycerol") as chain transfer agent, 0.015 g of 2,2'-azobis(2,4-dimethylvaleronitrile) (Fujifilm Wako Pure Chemical Industries, Ltd., "V-65") as polymerization initiator, 8.89 g of tetrahydrofuran (THF) as organic solvent, and 7.89 g of ethanol as organic solvent were mixed and dissolved at room temperature using a vortex mixer. Next, the atmosphere inside the vessel was replaced with nitrogen, and polymerization was carried out in a glove box for 24 hours at 55°C. After polymerization, the copolymer was purified by reprecipitation in hexane, and the purified copolymer was dried for 16 hours under vacuum conditions at 70°C using a vacuum oven (Espec Corporation's "Vacuum Oven LHV-112"). The dried copolymer was subjected to the above measurements and evaluations.

[0195] Example 2 A copolymer was prepared in the same manner as in Example 1, except that the amount of Blenmer AE-200 used was 2.45 g and the amount of DMA used was 0.21 g. The prepared copolymer was subjected to the above-described measurements and evaluations. Furthermore, the sulfur content measured by the sulfur content measurement method was 2,300 mg / kg.

[0196] Example 3 A copolymer was prepared in the same manner as in Example 1, except that the amount of Blenmer AE-200 used was 2.18 g, the amount of DMA used was 0.42 g, and the amount of 1-thioglycerol used was 0.026 g. The prepared copolymer was subjected to the above measurements and evaluations.

[0197] Example 4 A copolymer was prepared in the same manner as in Example 1, except that the amount of Blenmer AE-200 used was 1.91 g, the amount of DMA used was 0.66 g, and the amount of 1-thioglycerol used was 0.026 g. The prepared copolymer was subjected to the above measurements and evaluations.

[0198] Example 5 A copolymer was prepared in the same manner as in Example 1, except that 5.85 g of polyethylene glycol monoacrylate (NOF Corporation's "Blenmer AE-400", n≈10, 514.6 g / mol) was used as the monomer (a), the amount of DMA used was 0.08 g, the amount of 1-thioglycerol used was 0.089 g, the amount of V-65 used was 0.134 g, the amount of THF used was 15.7 g, and the amount of isopropanol used was 15.7 g. The prepared copolymer was subjected to the above measurements and evaluations.

[0199] Example 6 A copolymer was produced in the same manner as in Example 1, except that the amounts of Blemmer AE-400 used were 5.75 g, DMA used 0.20 g, 1-thioglycerol used 0.089 g, V-65 used 0.134 g, THF used 15.7 g, and isopropanol used 15.7 g. The produced copolymer was subjected to the above measurements and evaluations.

[0200] Example 7 A copolymer was produced in the same manner as in Example 1, except that the amounts of Blemmer AE-400 used were 5.35 g, DMA used 0.58 g, 1-thioglycerol used 0.089 g, V-65 used 0.134 g, THF used 15.7 g, and isopropanol used 15.7 g. The produced copolymer was subjected to the above measurements and evaluations.

[0201] Example 8 A copolymer was produced in the same manner as in Example 1, except that the amounts of Blemmer AE-400 used were 5.00 g, DMA used 0.92 g, 1-thioglycerol used 0.089 g, V-65 used 0.134 g, THF used 15.7 g, and isopropanol used 15.7 g. The produced copolymer was subjected to the above measurements and evaluations.

[0202] Example 9 A copolymer was produced in the same manner as in Example 1, except that 1.77 g of 2-acryloyloxyethyl acid phosphate ("Light Acrylate P-1A(N)" manufactured by Kyoeisha Chemical Co., Ltd., 196.1 g / mol) was used as the monomer (a), the amounts of DMA used were 0.21 g, the amounts of 1-thioglycerol used were 0.069 g, and the amount of V-65 used was 0.030 g, and 15.8 g of ethanol alone was used as the organic solvent. The produced copolymer was subjected to the above measurements and evaluations.

[0203] Example 10 A copolymer was prepared in the same manner as in Example 1, except that 2.18 g of Blemmer AE-200 and 0.52 g of polyethylene glycol monoacrylate (NOF Corporation's "Blemmer AE-400", n≈10, 514.6 g / mol) were used, and the amount of DMA used was 0.21 g and the amount of 1-thioglycerol used was 0.145 g. The prepared copolymer was subjected to the above measurements and evaluations.

[0204] Example 11 A copolymer was prepared in the same manner as in Example 1, except that the amount of Blenmer AE-200 used was 2.45 g, the amount of DMA used was 0.21 g, and the amount of 1-thioglycerol used was 0.0013 g. The prepared copolymer was subjected to the above measurements and evaluations.

[0205] Example 12 A copolymer was prepared in the same manner as in Example 1, except that the amounts of Blenmer AE-200 used were 2.45 g, DMA used were 0.21 g, and 1-thioglycerol used were 0.213 g. The prepared copolymer was subjected to the above measurements and evaluations.

[0206] Comparative Example 1 In a glass container, 1.91 g of 2-methoxyethyl acrylate (130.1 g / mol) as a monomer, 0.61 g of DMA as monomer (b), 0.042 g of azobisisobutyronitrile ("AIBN" manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerization initiator, and 10 g of N,N-dimethylformamide (DMF) as an organic solvent were mixed and dissolved using a vortex mixer at room temperature. The atmosphere inside the container was then replaced with nitrogen, and polymerization was carried out in a glove box at 60°C for 19 hours. After polymerization, the copolymer was purified by reprecipitation into hexane, and the purified copolymer was dried in a vacuum oven at 70°C under vacuum conditions for 16 hours. The above measurements and evaluations were carried out on the dried copolymer. The copolymer obtained in Comparative Example 1 was insoluble in water, so dispersibility could not be measured.

[0207] (Comparative Example 2) In a glass container, 1.78 g of N,N-dimethylacrylamide (99.1 g / mol) as a monomer, 0.21 g of DMA as monomer (b), 0.020 g of 1-thioglycerol as a chain transfer agent, 0.015 g of V-65 as a polymerization initiator, and 17.8 g of tetrahydrofuran (THF) as an organic solvent were mixed and dissolved using a vortex mixer at room temperature. Next, the atmosphere inside the container was replaced with nitrogen, and polymerization was carried out in a glove box at 55°C for 24 hours. After polymerization, the copolymer was purified by reprecipitation into hexane, and the purified copolymer was dried for 16 hours under vacuum conditions at 70°C using a vacuum oven. The above measurements and evaluations were carried out on the dried copolymer. The copolymer obtained in Comparative Example 2 was insoluble in water, so dispersibility could not be measured.

[0208] The copolymers obtained in Examples 2 and 6 were used to carry out the following Test Examples 1 to 3. In Test Examples 1 to 3, if the average particle diameter of the dispersion measured was within the range of 200 nm to 350 nm, the dispersion was evaluated as having been dispersed with a primary particle diameter. On the other hand, if the average particle diameter of the dispersion measured was greater than 350 nm, the dispersion was evaluated as having aggregated particles.

[0209] (Test Example 1) A dispersion (PTFE particle solids concentration = 29.3 mass%) was obtained in the same manner as in the above-mentioned dispersibility evaluation method, except that the amount of ion-exchanged water used was changed to 13.5 g, the amount of PTFE particles used was 6 g, the amount of surfactant used was 0.85 g, and the amount of copolymer obtained in Example 2 was changed to 0.12 g. The average particle size of the obtained dispersion was measured using the same equipment and measurement conditions as in the above-mentioned dispersibility evaluation method. The measured average particle size of the dispersion was 277 nm, confirming that the dispersion was dispersed at the primary particle size.

[0210] (Test Example 2) A dispersion (PTFE particle solids concentration = 29.3 mass%) was obtained in the same manner as in the above-mentioned dispersibility evaluation method, except that the amount of ion-exchanged water used was changed to 13.5 g, the amount of PTFE particles used was changed to 6 g, the amount of surfactant used was changed to 0.85 g, and the amount of copolymer obtained in Example 6 was changed to 0.12 g. The average particle size of the obtained dispersion was measured using the same equipment and measurement conditions as in the above-mentioned dispersibility evaluation method. The measured average particle size of the dispersion was 277 nm, which confirmed that the dispersion was dispersed with a primary particle size.

[0211] (Test Example 3) A dispersion (PTFE particle solids concentration = 50 mass%) was obtained in the same manner as in the above-mentioned dispersibility evaluation method, except that the amount of ion-exchanged water used was changed to 13.2 g, the amount of PTFE particles used was 15 g, the amount of surfactant used was 1.5 g, and the amount of copolymer obtained in Example 6 was changed to 0.30 g. The average particle diameter of the obtained dispersion was measured using the same equipment and measurement conditions as in the above-mentioned dispersibility evaluation method. The measured average particle diameter of the dispersion was 256 nm, which confirmed that the dispersion was dispersed with a primary particle diameter.

[0212] The results of each example and each comparative example are shown in Table 1. In Table 1, monomer (a) means "monomer (a) having a hydrophilic group (excluding a catechol group)" and monomer (b) means "monomer (b) having a catechol group."

[0213]

Claims

1. A copolymer containing a structural unit (A) derived from a monomer (a) having a hydrophilic group (excluding a catechol group) and a structural unit (B) derived from a monomer (b) having a catechol group, wherein the hydrophilic group is a hydroxy group and / or a phosphate group, and the copolymer has a mass average molecular weight of 500 or more and 20,000 or less.

2. The copolymer according to claim 1, wherein the monomer (a) is a monomer represented by the following formula (1): (In the formula, R １ represents a hydrogen atom or a linear or branched alkyl group having 1 to 20 carbon atoms. X represents an amide bond (-C(O)NH- or -NHC(O)-) or an ester bond (-C(O)O- or -OC(O)-). R ２ represents a single bond, a linear or branched alkylene group having 1 to 10 carbon atoms which may have a substituent, or a linear or branched oxyalkylene group having 1 to 10 carbon atoms which may have a substituent. n represents a number of 1 to 20 on average. ２ is a single bond or a linear or branched alkylene group having 1 to 10 carbon atoms which may have a substituent, R ３ R represents a hydroxyl group or a phosphate group. ２ is a linear or branched oxyalkylene group having 1 to 10 carbon atoms which may have a substituent, R ３ represents a hydrogen atom, a hydroxyl group, or a phosphate group.

3. The copolymer according to claim 1, wherein the monomer (b) is a monomer represented by the following formula (2): (In the formula, R ４ represents a hydrogen atom or a linear or branched alkyl group having 1 to 20 carbon atoms. Y represents an amide bond (-C(O)NH- or -NHC(O)-) or an ester bond (-C(O)O- or -OC(O)-). R ５ R represents a single bond or a linear or branched alkylene group having 1 to 10 carbon atoms which may have a substituent. ６ represents a single bond, an ether bond (-O-), -CH(OH)-, an ester bond (-C(O)O- or -OC(O)-), or a carbonate group (-OC(O)O-).

4. The copolymer according to any one of claims 1 to 3, and a surface free energy of 70 mJ / m ２ and a particle less than about 100 nm in diameter, wherein the copolymer is attached to a surface of the particle.

5. The composite particle according to claim 4, further comprising a surfactant, said surfactant being attached to the surface of said particle.

6. A composite particle dispersion comprising: the composite particle according to claim 4; and an aqueous solvent, the composite particle being dispersed in the aqueous solvent.

7. A composite particle dispersion comprising: the composite particle according to claim 5; and an aqueous solvent, the composite particle being dispersed in the aqueous solvent.

8. A method for producing the copolymer according to any one of claims 1 to 3, comprising a step of copolymerizing the monomer (a) and the monomer (b) in the presence of a chain transfer agent.

9. A dispersant comprising the copolymer according to any one of claims 1 to 3.

10. A coating agent comprising the copolymer according to any one of claims 1 to 3.

11. A coating material comprising the copolymer according to any one of claims 1 to 3.

12. A lubricating coating comprising the copolymer according to any one of claims 1 to 3.

13. A battery comprising the copolymer according to any one of claims 1 to 3.

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