Copolymers, coatings and articles

Abstract

The present invention relates to a copolymer comprising a structural unit (A) having a cyclic carbonate structure and a structural unit (B) having a hydrophilic structure.

Description

[Technical Field]

[0001] The present invention relates to copolymers, coatings and articles. [Background technology]

[0002] Polymers containing structural units with a cyclic carbonate structure are widely used in resin compositions for paints. For example, Patent Document 1 discloses a resin composition for paints used for painting automobile parts, etc., which contains a polymer composed of a (meth)acrylate having a cyclic carbonate structure and a (meth)acrylate monomer, a curing catalyst, and a crosslinking agent. Patent Document 2 discloses a curable resin composition containing a copolymer containing repeating units of a (meth)acrylic acid ester having a five-membered cyclic carbonate group and repeating units of an alkyl (meth)acrylate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-229770 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-36081 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional resin compositions containing polymers with structural units having a cyclic carbonate structure have not been used for hydrophilic coating applications. While various hydrophilic coating agents are known, attempts to enhance hydrophilicity can impair the water resistance of the coating, resulting in a decrease in hydrophilicity over time, making it difficult to achieve both high hydrophilicity and water resistance.

[0005] Therefore, an object of the present invention is to provide a coating agent capable of imparting a coating having both high hydrophilicity and high water resistance, and a copolymer suitable for such a coating agent. [Means for solving the problem]

[0006] In order to solve the above problems, the present inventors have investigated the structure of copolymers contained in compositions for coating agents, and have found that the above problems can be solved by a copolymer having a structural unit (A) with a cyclic carbonate structure and a structural unit (B) with a hydrophilic structure, thereby completing the present invention.

[0007] That is, the present invention includes the following preferred embodiments. [1] A copolymer having at least a structural unit (A) having a cyclic carbonate structure and a structural unit (B) having a hydrophilic structure. [2] The copolymer according to [1], wherein the structural unit (B) having a hydrophilic structure is neutral in charge. [3] The copolymer according to [1] or [2], wherein the hydrophilic structure is at least one structure selected from the group consisting of a betaine structure, an amide structure, an alkylene oxide structure, and a lactam structure. [4] The copolymer according to any one of [1] to [3], wherein the hydrophilic structure includes a betaine structure having at least one atom selected from the group consisting of a positively charged quaternary nitrogen atom, a positively charged tertiary sulfur atom, and a positively charged quaternary phosphorus atom. [5] The betaine structure is represented by the formula (1): [ka] [In the formula, R 1 represents a linear or branched alkylene group having 1 to 6 carbon atoms, R 2 each independently represents a linear or branched alkyl group having 1 to 4 carbon atoms, R 3 represents a linear or branched alkylene group having 1 to 4 carbon atoms, Y is -SO3 - or -COO - represents * represents a bond. The copolymer according to [4], represented by the formula: [6] The copolymer according to any one of [1] to [5], wherein the structural unit (A) and the structural unit (B) are structural units derived from a (meth)acrylic monomer or a vinyl monomer. [7] A coating agent comprising the copolymer according to any one of [1] to [6] and a crosslinking agent. [8] A coating agent comprising at least a first agent and a second agent, the coating agent according to [7], wherein the first agent contains the copolymer according to any one of [1] to [6], and the second agent contains a crosslinking agent. [9] The coating agent according to [7] or [8], wherein the crosslinking agent is at least one selected from the group consisting of polyamines and polyols.

[10] An article (excluding long medical instruments and components thereof) coated with a cured film of the coating agent according to any one of [7] to [9].

[11] A copolymer having at least a structural unit (B) having a hydrophilic structure represented by the following formula (2): -X 1 -ZR 4 -ZX 2 - (2) [In the formula, X 1 and X 2 are, independently of each other, -CH(OH)-CH(R 6 )-OC(=O)-* and / or -CH(CH(R 6 )(OH))-OC(=O)-*, * is bonded to Z in formula (2), R 4 represents a linear or branched alkylene group having 1 to 11 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms containing an alicyclic structure having 3 to 6 carbon atoms, or an aromatic group having 6 to 20 carbon atoms containing an aromatic ring structure having 6 to 10 carbon atoms, R 6 represents a hydrogen atom, or a linear or branched alkyl or alkenyl group having 1 to 4 carbon atoms, where R 6at least one hydrogen atom of which may be substituted with a halogen atom, and at least one carbon atom (—C—) of which may be substituted with —O—, —S—, or —P—; Z represents -O- or -N(-H)-. The article according to

[10] , which is coated with a polymer material crosslinked with a crosslinked structure represented by the formula: [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a coating agent capable of imparting a coating having both high hydrophilicity and high water resistance, and a copolymer suitable for the coating agent. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 10 is an explanatory diagram showing the evaluation results of adhesion. [Figure 2] FIG. 2 is an explanatory diagram showing the change in viscosity of a coating agent over time. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail. Note that the scope of the present invention is not limited to the embodiments described here, and various modifications can be made without departing from the spirit of the present invention.

[0011] [Copolymer] The copolymer of the present invention is a copolymer having at least a structural unit (A) having a cyclic carbonate structure and a structural unit (B) having a hydrophilic structure. By using a copolymer having a combination of a structural unit (A) having a cyclic carbonate structure and a structural unit (B) having a hydrophilic structure, it is possible to impart high hydrophilicity and water resistance to the surface of an article coated with a cured product of the copolymer.

[0012] (Structural unit (A) having a cyclic carbonate structure) The structural unit (A) having a cyclic carbonate structure is a structural unit derived from a monomer having a cyclic carbonate structure. When the copolymer contains the structural unit (A) having a cyclic carbonate structure, the water resistance of the substrate surface coated with a cured product of the copolymer can be improved. The cyclic carbonate structure may be a cyclic carbonate group, and the number of ring members in the cyclic carbonate group moiety is preferably 3 to 8, more preferably 4 to 7, and even more preferably 5 to 6. Examples of such cyclic carbonate structures include structures containing an ethylene carbonate group, a propylene carbonate group, a butylene carbonate group, or a pentylene carbonate group, which may have a substituent, and preferably a structure containing an ethylene carbonate group which may have a substituent. The cyclic carbonate structure is preferably represented by the following formula (3): [ka] [In the formula, R 5 represents a linear or branched alkylene or alkenylene group having 1 to 4 carbon atoms, where R 5 at least one hydrogen atom of which may be substituted with a halogen atom, and at least one carbon atom (—C—) of which may be substituted with —O—, —S—, or —P—; R 6 represents a hydrogen atom, or a linear or branched alkyl or alkenyl group having 1 to 4 carbon atoms, where R 6 at least one hydrogen atom of which may be substituted with a halogen atom, and at least one carbon atom (-C-) of which may be substituted with -O-, -S-, or -P-. The copolymer of the present invention may have one type of structural unit (A) having a cyclic carbonate structure, or may have two or more types of structural units (A).

[0013] R 5In the formula, examples of the linear or branched alkylene group having 1 to 4 carbon atoms include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an n-butylene group, a methylmethylene group, a methylethylene group, a dimethylethylene group, and a methylpropylene group. Examples of the linear or branched alkenylene group having 1 to 4 carbon atoms include groups in which at least one, preferably one, of the direct carbon-carbon bonds of the alkylene group is replaced with an unsaturated double bond. From the viewpoint of easily improving water resistance, R 5 is preferably a linear or branched alkylene group having 1 to 4 carbon atoms.

[0014] R 6 In the formula, examples of the linear or branched alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, etc. Examples of the linear or branched alkenyl group having 1 to 4 carbon atoms include groups in which at least one, preferably one, of the direct carbon-carbon bonds of the above alkyl groups is replaced with an unsaturated double bond. From the viewpoint of easily improving water resistance, R 6 is preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom.

[0015] (Structural unit (B) having a hydrophilic structure) The structural unit (B) having a hydrophilic structure is a structural unit derived from a monomer having a hydrophilic structure. The hydrophilic structure is not particularly limited as long as it has a hydrophilic group that easily increases the hydrophilicity of the copolymer. From the viewpoint of easily increasing the hydrophilicity of the copolymer, it is preferably at least one structure selected from the group consisting of a betaine structure, an amide structure, an alkylene oxide structure, and a lactam structure. From the viewpoint of biocompatibility, protein adhesion prevention, and cell adhesion prevention, the structural unit (B) is preferably neutral in charge. Note that the structural unit (B) being neutral in charge means that the sum of the cationic charge and the anionic charge in the structural unit (B) is zero.

[0016] The copolymer of the present invention may have one type of structural unit (B) having a hydrophilic structure, or may have two or more types of structural units (B). In a preferred embodiment of the present invention, the structural unit (B) having a hydrophilic structure in the copolymer of the present invention includes at least a structural unit (B1) having a betaine structure. In this case, in addition to the structural unit (B1), the structural unit (B) may further include a structural unit (B2) having at least one structure selected from the group consisting of an amide structure, an alkylene oxide structure, and a lactam structure, from the viewpoints of improving the applicability of the coating agent and obtaining a flexible cured film. In this embodiment, the amount of the structural unit (B1) having a betaine structure in the copolymer of the present invention is preferably 10 mol % or more, more preferably 20 mol % or more, even more preferably 30 mol % or more, and even more preferably 40 mol % or more, based on the amount of all structural units contained in the copolymer of the present invention, from the viewpoints of easily increasing the hydrophilicity and water resistance of the cured film of the present invention and easily increasing the swelling property of the cured film. The term "betaine structure" refers to a structure in which a positive charge and a negative charge are not adjacent to each other in the same molecule, and the positively charged atom is not bound to a dissociable hydrogen atom, resulting in a neutral (non-charged) structure overall. In the betaine structure, the positively charged functional group can be, for example, a quaternary ammonium, a tertiary sulfonium, or a quaternary phosphonium, and the negatively charged functional group can be, for example, a sulfonic acid, a carboxylic acid, or a phosphonic acid. That is, the betaine structure can be, for example, a sulfobetaine, a carboxybetaine, or a phosphobetaine.

[0017] From the viewpoint of easily increasing the hydrophilicity of the copolymer, the hydrophilic structure in the structural unit (B) preferably contains a betaine structure having at least one atom selected from the group consisting of a positively charged quaternary nitrogen atom, a positively charged tertiary sulfur atom, and a positively charged quaternary phosphorus atom, and more preferably contains a betaine structure having a positively charged quaternary nitrogen atom. A betaine structure having a positively charged quaternary nitrogen atom is preferred because it can act as a catalyst in the crosslinking reaction with a crosslinking agent in a coating agent containing the copolymer of the present invention.

[0018] The betaine structure having a positively charged quaternary nitrogen atom is preferably represented by formula (1): [ka] [In the formula, R 1 represents a linear or branched alkylene group having 1 to 6 carbon atoms, R 2 each independently represents a linear or branched alkyl group having 1 to 4 carbon atoms, R 3 represents a linear or branched alkylene group having 1 to 4 carbon atoms, Y is -SO3 - or -COO - represents * represents a bond. It is expressed as:

[0019] The betaine structure having a positively charged tertiary sulfur atom is preferably represented by formula (4): [ka] [In the formula, R 1 represents a linear or branched alkylene group having 1 to 6 carbon atoms, R 2 represents a linear or branched alkyl group having 1 to 4 carbon atoms, R 3 represents a linear or branched alkylene group having 1 to 4 carbon atoms, Y is -SO3 -or -COO - represents * represents a bond. It is expressed as:

[0020] The betaine structure having a positively charged quaternary phosphorus atom is preferably represented by formula (5): [ka] [In the formula, R 1 represents a linear or branched alkylene group having 1 to 6 carbon atoms, R 2 each independently represents a linear or branched alkyl group having 1 to 4 carbon atoms, R 3 represents a linear or branched alkylene group having 1 to 4 carbon atoms, Y is -SO3 - or -COO - represents * represents a bond. It is expressed as:

[0021] R in formulas (1), (4) and (5) 1 Examples of the linear or branched alkylene group having 1 to 6 carbon atoms in R include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an n-butylene group, an n-pentylene group, an n-hexylene group, an isobutylene group, a methylmethylene group, a methylethylene group, a dimethylethylene group, a methylpropylene group, a methylbutylene group, and a methylpentylene group. 1 is preferably a linear or branched alkylene group having 1 to 4 carbon atoms, more preferably a linear or branched alkylene group having 1 to 3 carbon atoms.

[0022] R in formulas (1), (4) and (5) 2 Examples of the linear or branched alkyl group having 1 to 4 carbon atoms in R include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and an isobutyl group. 2is preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group or an ethyl group, and even more preferably a methyl group.

[0023] R in formulas (1), (4) and (5) 3 Examples of the linear or branched alkylene group having 1 to 4 carbon atoms in R include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an n-butylene group, a methylmethylene group, a methylethylene group, a dimethylethylene group, and a methylpropylene group. 3 is preferably an alkylene group having 1 to 3 carbon atoms, more preferably a methylene group or an ethylene group, and even more preferably a methylene group.

[0024] Y in formulas (1), (4) and (5) is -SO3 - or -COO - and preferably represents -COO - Represents.

[0025] The amide structure refers to a structure having -C(=O)-NH-, and a representative example is a (meth)acrylamide structure having a (meth)acryl group. Specific examples of monomers having a (meth)acrylamide structure include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-(meth)acrylmorpholide, N-methoxymethyl(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-monomethyl(meth)acrylamide, and N-monoethyl(meth)acrylamide.

[0026] The alkylene oxide structure refers to a structure in which some of the carbon atoms forming the alkyl chain are substituted with oxygen. Specific examples of monomers having an alkylene oxide structure include ethylene glycol, methoxyethylene glycol, ethoxyethylene glycol, 2-propylene glycol, 2-methoxypropylene glycol, 2-ethoxypropylene glycol, 3-propylene glycol, 3-methoxypropylene glycol, 3-ethoxypropylene glycol, 2-butylene glycol, 3-butylene glycol, 4-butylene glycol, polyethylene glycol, methoxypolyethylene glycol, polypropylene glycol, methoxypolypropylene glycol, and polybutylene glycol. Other specific examples of monomers having an alkylene oxide structure include those having a (meth)acrylic group, and specific examples thereof include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, polyethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, ethoxypolyethylene glycol (meth)acrylate, polyethylene glycol di(meth)acrylate, and 2-hydroxyethyl vinyl ether.

[0027] A lactam structure is a ring structure formed by dehydration condensation of a carboxy group and an amino group, and examples thereof include α-lactam (three-membered ring), β-lactam (four-membered ring), γ-lactam (five-membered ring), δ-lactam (six-membered ring), etc. Specific examples of monomers having a lactam structure include N-vinyl-2-caprolactam, N-vinylpyrrolidone, and N-vinylpiperidone.

[0028] (Other structural units) The copolymer of the present invention may further contain other structural units in addition to one or more of the structural units (A) and one or more of the structural units (B) described above. Examples of other structural units include structural units derived from alkoxyalkyl group-containing (meth)acrylic monomers such as 2-methoxyethyl (meth)acrylate, and structural units derived from acrylamide monomers such as diacetone (meth)acrylamide, N-methylol (meth)acrylamide, and hydroxyethyl (meth)acrylamide.

[0029] The total amount of the structural unit (A) and the structural unit (B) contained in the copolymer of the present invention is, from the viewpoint of water resistance and swelling property, preferably 20 mol% or more, more preferably 30 mol% or more, and even more preferably 50 mol% or more, based on all structural units contained in the copolymer of the present invention. Furthermore, the total amount may be 100 mol% or less. The amounts of the structural unit (A) and the structural unit (B) in the copolymer may be calculated by analyzing the structure of the copolymer by NMR or the like, or may be calculated from the amounts of each monomer when producing the copolymer.

[0030] From the viewpoint of swelling property, the molar ratio (A / B) of the structural unit (A) to the structural unit (B) contained in the copolymer of the present invention is preferably 1 / 99 or more, more preferably 5 / 95 or more, even more preferably 10 / 90 or more, and is preferably 99 / 1 or less, more preferably 50 / 50 or less, even more preferably 30 / 70 or less, and particularly preferably 25 / 75 or less.

[0031] The proportion of the structural unit (A) contained in the copolymer of the present invention is preferably 3 mol% or more, more preferably 5 mol% or more, based on the amount of all structural units, from the viewpoint of easily increasing the water resistance and adhesion of the copolymer, and the proportion of the structural unit (A) is preferably 30 mol% or less, more preferably 25 mol% or less, even more preferably 20 mol% or less, and even more preferably 15 mol% or less.

[0032] The proportion of the structural unit (B) (hydrophilic monomer) contained in the copolymer of the present invention is preferably 60 mol % or more, more preferably 70 mol % or more, and even more preferably 80 mol % or more, based on the amount of all structural units, from the viewpoint of easily increasing the water resistance and adhesion of the copolymer. The proportion of the structural unit (B) is preferably 98 mol % or less, more preferably 95 mol % or less.

[0033] When the structural unit (B) (hydrophilic monomer) contained in the copolymer of the present invention contains the structural unit (B1) (structural unit having a betaine structure), the proportion of the structural unit (B1) is preferably 20 mol% or more, more preferably 30 mol% or more, and even more preferably 40 mol% or more, based on the amount of all structural units, from the viewpoint of easily improving the water resistance and adhesion of the copolymer. Moreover, the proportion of the structural unit (B1) is preferably 98 mol% or less, more preferably 95 mol% or less.

[0034] When the structural unit (B) contained in the copolymer of the present invention contains the above structural units (B1) and (B2), the proportion of the structural unit (B1) is, based on the amount of all structural units, preferably 20 mol% or more, more preferably 30 mol% or more, even more preferably 40 mol% or more, and preferably 98 mol% or less, more preferably 95 mol% or less, and the proportion of the structural unit (B2) is, based on the amount of all structural units, preferably 20 mol% or more, more preferably 30 mol% or more, even more preferably 40 mol% or more, and preferably 70 mol% or less, more preferably 60 mol% or less.

[0035] The structural units (A) and (B) and other structural units that may be included are derived from monomers having polymerizable groups that are copolymerizable with each other. Examples of such monomers include (meth)acrylic monomers and vinyl monomers. From the viewpoint of ease of production of the copolymer, the structural units (A) and (B) are preferably structural units derived from (meth)acrylic monomers or vinyl monomers.

[0036] When the structural units (A) and (B) are (meth)acrylic monomers, the structural unit (A) is, for example, a monomer represented by the following formula (6): [ka] [In the formula, R 7a is a hydrogen atom or a methyl group, M a represents -NH- or -O-; P a represents a cyclic carbonate structure, preferably the above formula (3)] The structural unit may be derived from a monomer represented by the formula: As such a monomer, for example, (2-oxo-1,3-dioxolan-4-yl)methyl methacrylate (GCMA) or (2-oxo-1,3-dioxolan-4-yl)methyl acrylate (GCA) can be used, with (2-oxo-1,3-dioxolan-4-yl)methyl methacrylate (GCMA) being preferred. The structural unit (B) is represented by the following formula (7): [ka] [In the formula, R 7b is a hydrogen atom or a methyl group, M b represents -NH- or -O-; P b represents a hydrophilic structure, preferably a betaine structure, an amide structure, an alkylene oxide structure, or a lactam structure. In a preferred embodiment, the structural unit (B) may be a structural unit derived from a monomer represented by P in formula (7). b is preferably a betaine structure, more preferably a structure represented by any one of formulas (1), (4) and (5), and even more preferably a structure represented by formula (1). In a further preferred embodiment, the structural unit (B) is a structural unit derived from a monomer having a structure represented by P in formula (7). bis preferably a betaine structure, more preferably a structure represented by any one of formulas (1), (4) and (5), and even more preferably a structure represented by formula (1), and b and a structural unit (B2) derived from a monomer having preferably an amide structure, an alkylene oxide structure, or a lactam structure.

[0037] When the structural units (A) and (B) are vinyl monomers, the structural unit (A) may be, for example, a monomer represented by the following formula (8): [ka] [In the formula, P a represents a cyclic carbonate structure, preferably the above formula (3)] The structural unit may be derived from a monomer represented by the following formula: The structural unit (B) may be, for example, a structural unit represented by the following formula (9): [ka] [In the formula, P b represents a hydrophilic structure, preferably a betaine structure, an amide structure, an alkylene oxide structure, or a lactam structure. In a preferred embodiment, the structural unit (B) may be a structural unit derived from a monomer represented by P in formula (9). b is preferably a betaine structure, more preferably a structure represented by any one of formulas (1), (4) and (5), and even more preferably a structure represented by formula (1). In a further preferred embodiment, the structural unit (B) is a structural unit derived from a monomer having a structure represented by P in formula (9). b is preferably a betaine structure, more preferably a structure represented by any one of formulas (1), (4) and (5), and even more preferably a structure represented by formula (1), and b and a structural unit (B2) derived from a monomer having preferably an amide structure, an alkylene oxide structure, or a lactam structure.

[0038] From the viewpoint of easily increasing the stability of the coating agent and easily increasing adhesion to the substrate surface during application, the copolymer of the present invention is preferably soluble in water, more preferably soluble in water and methanol, even more preferably soluble in water, methanol, and ethanol, and even more preferably soluble in water, methanol, ethanol, and isopropanol. Whether the copolymer of the present invention is soluble in a solvent such as water can be determined by adding 90 parts of a solvent to 10 parts of a solid obtained by drying the copolymer, stirring at room temperature for 30 minutes, and allowing to stand for 24 hours. If a transparent solution is obtained, the copolymer is judged to be soluble, but if there is residual residue in the solution or the solution becomes cloudy, the copolymer is judged to be insoluble.

[0039] [Method for producing copolymer] The copolymer of the present invention can be produced by copolymerizing a monomer having a cyclic carbonate structure and a monomer having a hydrophilic structure, both of which have polymerizable groups copolymerizable with each other, optionally together with other monomers. When producing the copolymer, it is preferable to use at least one polymerization initiator in order to promote the polymerization reaction of the monomer components. Examples of polymerization initiators include azo-based fat-soluble polymerization initiators such as azoisobutyronitrile, methyl azoisobutyrate, and azobisdimethylvaleronitrile; azo-based water-soluble polymerization initiators such as 2,2'-azobis[2-(2-imidazolin-2-yl)propane], 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, and 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide]; inorganic peroxides such as benzoyl peroxide, potassium persulfate, and ammonium persulfate; and photopolymerization initiators such as benzophenone derivatives, phosphine oxide derivatives, benzoketone derivatives, phenylthioether derivatives, azide derivatives, diazo derivatives, and disulfide derivatives, but the present invention is not limited to these examples. These polymerization initiators may be used alone or in combination of two or more.

[0040] The amount of the polymerization initiator is not particularly limited, but is usually preferably about 0.01 to 5 parts by mass per 100 parts by mass of the monomer component.

[0041] Examples of polymerization methods for producing the copolymer of the present invention include bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization, but the present invention is not limited to these examples. Among these polymerization methods, solution polymerization is preferred. When polymerizing the monomer components by solution polymerization, for example, the monomer components can be polymerized by dissolving the monomer components in a solvent and adding a polymerization initiator while stirring the resulting solution. The polymerization method for producing the copolymer may be photopolymerization or thermal polymerization, but thermal polymerization is preferred from the viewpoint of manufacturability.

[0042] Examples of solvents include water; alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, ethylene glycol, and propylene glycol; ketones such as acetone and methyl ethyl ketone; ethers such as diethyl ether and tetrahydrofuran; aromatic hydrocarbon compounds such as benzene, toluene, and xylene; aliphatic hydrocarbon compounds such as n-hexane; alicyclic hydrocarbon compounds such as cyclohexane; acetate esters such as methyl acetate and ethyl acetate; and aprotic polar solvents such as dimethylformamide (hereinafter referred to as DMF) and dimethyl sulfoxide (hereinafter referred to as DMSO). However, the present invention is not limited to these examples. These solvents may be used alone or in combination of two or more.

[0043] The amount of the solvent is preferably adjusted so that the concentration of the monomer component in the solution obtained by dissolving the monomer component in the solvent is generally about 10 to 80% by mass.

[0044] The polymerization conditions, such as the polymerization temperature and polymerization time, when polymerizing the monomer components are preferably adjusted appropriately depending on the type and amount of the monomer used as the monomer component, the type and amount of the polymerization initiator used, etc.

[0045] The atmosphere during polymerization of the monomer components is preferably an inert gas, such as nitrogen gas or argon gas, but the present invention is not limited to these examples.

[0046] The weight-average molecular weight of the copolymer of the present invention is preferably 100 or more, more preferably 500 or more, even more preferably 1,000 or more, even more preferably 10,000 or more, and particularly preferably 50,000 or more, from the viewpoint of easily enhancing the hydrophilicity and water resistance of a coating (cured film) formed using the copolymer. From the viewpoint of solubility in solvents and ease of coating when used as a coating material, the weight-average molecular weight is preferably 1,000,000 or less, more preferably 500,000 or less, even more preferably 200,000 or less, and even more preferably 150,000 or less. The weight-average molecular weight of the copolymer of the present invention can be determined by gel permeation chromatography (hereinafter referred to as GPC). The weight-average molecular weight by GPC may be measured using, for example, trifluoroethanol as an eluent and a column (e.g., Wako Beads G-50, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). Polyethylene glycol may also be used as a molecular weight standard.

[0047] The viscosity average molecular weight of the copolymer of the present invention is preferably 100 or more, more preferably 500 or more, even more preferably 1,000 or more, and even more preferably 10,000 or more, from the viewpoint of easily enhancing the hydrophilicity and water resistance of a coating formed using the copolymer, and is preferably 1,000,000 or less, more preferably 500,000 or less, and even more preferably 200,000 or less, from the viewpoint of solubility in solvents and ease of coating when used as a coating material. The viscosity average molecular weight of the copolymer of the present invention may be measured, for example, using the method described in the Examples.

[0048] [Coating agent] The present invention also provides a coating agent containing the above-described copolymer. The amount of the copolymer contained in the coating agent of the present invention is not particularly limited, but from the viewpoint of easily imparting high hydrophilicity and water resistance to films, hydrogels, etc. obtained from the coating agent, it is preferably 1% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, based on the total amount of the coating agent of the present invention. Furthermore, the amount of the copolymer is not particularly limited, and can be 100% by mass or less, or even 90% by mass or less. The coating agent of the present invention may contain one type of copolymer of the present invention, or may contain two or more types of copolymers of the present invention.

[0049] The coating agent of the present invention may further contain at least one crosslinking agent in addition to at least one copolymer of the present invention. The crosslinking agent is not particularly limited as long as it is a compound capable of crosslinking the copolymer contained in the coating agent of the present invention. However, from the viewpoint of easily increasing the water resistance of the cured film of the coating agent of the present invention, a crosslinking agent capable of crosslinking with the cyclic carbonate structure in the copolymer of the present invention is preferred. Examples of such crosslinking agents include polyamines, polyols, and polycarboxylic acids, but the present invention is not limited to these examples. These crosslinking agents may be used alone or in combination of two or more. From the viewpoint of reactivity with the structural unit (A), the crosslinking agent is preferably at least one selected from the group consisting of polyamines and polyols, more preferably polyamines.

[0050] The polyamine is a compound having two or more amine groups. The polyamine may be either an aliphatic polyamine having an aliphatic structure or an aromatic polyamine having an aromatic structure. From the viewpoint of forming a cured product having excellent adhesion to the coating object and excellent yellowing resistance after curing, an aliphatic polyamine is preferred, and an aliphatic polyamine having two or more amine groups is more preferred. The aliphatic polyamine may have an alicyclic structure. Suitable aliphatic polyamines include, for example, isophorone diamine, norbornene diamine, 1,3-bisaminomethylcyclohexane, diethylenetriamine, triethylenetetramine, 4,4'-diaminocyclohexylmethane, ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,12-diaminododecane, tetraethylenepentamine, pentaethylenehexamine, polyoxyalkylene diamines such as polyoxyethylene diamines and polyoxypropylene diamines; polyoxyalkylene triamines such as polyoxyethylene triamines and polyoxypropylene triamines; and aminoethylated acrylic polymers.

[0051] A polyol is a compound having two or more hydroxy groups. Examples of polyols include polyester polyols, polyether polyols, and polycarbonate polyols. Examples of polyester polyols include condensation polymers and ring-opening polymers of polyhydric alcohols and polycarboxylic acids. Examples of polyols in the condensation polymers of polyhydric alcohols and polycarboxylic acids include ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, cyclohexanedimethanol, glycerin, and 1,1,1-trimethylolpropane. Examples of polyether polyols include polymers and ring-opening polymers of polyols and alkylene oxides. In the polymer of polyhydric alcohol and alkylene oxide, examples of polyols include ethylene glycol, diethylene glycol, polyoxyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, polyoxypropylene glycol, glycerin, 1,1,1-trimethylolpropane, 1,2,5-hexanetriol, 1,3-butanediol, 1,4-butanediol, polyoxypropylenetriol, 4,4'-dihydroxyphenylpropane, 4,4'-dihydroxyphenylmethane, and pentaerythritol. Examples of alkylene oxides include propylene oxide, ethylene oxide, butylene oxide, and styrene oxide. Examples of ring-opening polymers include polytetramethylene glycol obtained by ring-opening polymerization of tetrahydrofuran, etc.

[0052] When the coating agent of the present invention contains a crosslinking agent, the amount of crosslinking agent contained in the coating agent is not particularly limited, but from the viewpoint of easily improving the water resistance of the cured film of the coating agent of the present invention, it is preferably 0.01 to 99.99 mass%, more preferably 0.1 to 99.9 mass%, even more preferably 1 to 99 mass%, and even more preferably 2 to 98 mass%, based on the total amount of the coating agent of the present invention. From the viewpoint of easily improving the water resistance of the cured film of the coating agent of the present invention, the mass ratio of the amount of crosslinking agent (curing agent) to the amount of the copolymer of the present invention contained in the coating agent of the present invention is preferably copolymer:curing agent = 10:1 or less, more preferably copolymer:curing agent = 8:1 or less, and even more preferably copolymer:curing agent = 6:1 or less.

[0053] The coating agent of the present invention may further contain at least one solvent in addition to at least one of the copolymers described above. Examples of solvents include water; alcoholic solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, ethylene glycol, and propylene glycol; ketones such as acetone and methyl ethyl ketone; ethers such as diethyl ether and tetrahydrofuran; and aprotic polar solvents such as DMF and DMSO, but the present invention is not limited to these examples. These solvents may be used alone or in combination of two or more. From the viewpoint of improving the ease of handling of the coating agent of the present invention, the solvent is preferably water or an alcoholic solvent.

[0054] The amount of solvent contained in the coating agent of the present invention is not particularly limited, but is preferably 0.01 to 99.99 mass %, more preferably 0.1 to 99.9 mass %, based on the total amount of the coating agent of the present invention.

[0055] In a preferred embodiment of the present invention, the coating agent of the present invention may be a two-component coating agent comprising at least a first component and a second component. In this case, for example, the first component may contain the copolymer of the present invention described above, and the second component may contain a crosslinking agent. In this embodiment, the copolymer in the first component and the crosslinking agent in the second component can be prevented from reacting during storage, thereby providing a coating agent with excellent stability. In this embodiment, the first component and the second component are mixed preferably 1 minute to 24 hours, more preferably 1 minute to 12 hours, and even more preferably 1 minute to 2 hours before use of the coating agent, and the resulting mixture is used as the coating agent. The mixing ratio of the first component to the second component is preferably 10:1 to 1:10, more preferably 5:1 to 1:5, based on the mass ratio of the copolymer in the first component to the crosslinking agent in the second component.

[0056] The coating agent of the present invention may contain other components in addition to the copolymer, crosslinker, and optional solvent. The other components may be selected appropriately depending on the intended use of the coating agent of the present invention, and examples thereof include inorganic particles, organic particles, pigments, dyes, thickeners, surface tension agents, wettability modifiers, thixotropy regulators, surfactants, antifoaming agents, antioxidants, and ultraviolet absorbers. The amount of the other components may also be adjusted appropriately depending on the intended use of the coating agent of the present invention and the functions of the other components, and is, for example, 0.01 to 99.99% by mass based on the coating agent of the present invention.

[0057] The crosslinking reaction between the copolymer contained in the coating agent of the present invention and a crosslinking agent capable of crosslinking the copolymer proceeds even at a relatively low temperature, for example, around 80°C. Furthermore, since the reaction proceeds irreversibly even in water, a coating film with excellent water resistance can be obtained. Taking the case where the crosslinking agent is a polyamine (e.g., diamine) as an example, the chemical reaction between the copolymer contained in the coating agent of the present invention and the crosslinking agent is explained using the following formula:

[0058] [ka]

[0059] When the copolymer of the present invention having at least a structural unit (A) having a cyclic carbonate structure and a structural unit (B) having a hydrophilic structure is reacted with a crosslinking agent (e.g., polyamine), as described above, the cyclic carbonate group undergoes ring-opening at the -C(=O)-O- bond portion and reacts with the crosslinking agent, resulting in a structure in which the main chains of the copolymer having the structural unit (B) having a hydrophilic structure are crosslinked together via the polyhydroxyurethane bond portion. For example, an example of the copolymer and crosslinking agent of the present invention will be described using the above chemical reaction formula. In the above chemical reaction formula, the structural unit (A) of the copolymer reacts with the crosslinking agent, and the reaction occurs at both ends of the crosslinking agent, resulting in crosslinking of the main chains of the copolymer, represented by the wavy lines, via the polyhydroxyurethane bond. Here, depending on which -C(=O)-O- bond the ring-opening of the cyclic carbonate group occurs at, the above crosslinked structures (i) to (iii) can be formed. Note that the structural unit (B) having a hydrophilic structure of the copolymer is omitted in the above chemical formula. Furthermore, in the above diagram, when a polyol is used as the crosslinking agent instead of a polyamine, a crosslinked structure in which the -N(-H)- moiety is -O- is formed.

[0060] As a result, in a preferred embodiment of the present invention, an article coated with a cured film of the coating agent of the present invention obtained after crosslinking has a copolymer having at least a structural unit (B) having a hydrophilic structure represented by the following formula (2): -X 1 -ZR 4 -ZX 2 - (2) [In the formula, X 1 and X 2 are, independently of each other, -CH(OH)-CH(R 6 )-OC(=O)-* and / or -CH(CH(R 6 )(OH))-OC(=O)-*, * is bonded to Z in formula (2), R 4represents a linear or branched alkylene group having 1 to 11 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms containing an alicyclic structure having 3 to 6 carbon atoms, or an aromatic group having 6 to 20 carbon atoms containing an aromatic ring structure having 6 to 10 carbon atoms; R 4 represents a linear alkylene group preferably having 1 to 11 carbon atoms, more preferably a linear alkylene group having 1 to 6 carbon atoms, and even more preferably a linear alkylene group having 4 to 6 carbon atoms; R 6 represents a hydrogen atom, or a linear or branched alkyl or alkenyl group having 1 to 4 carbon atoms, where R 6 at least one hydrogen atom of which may be substituted with a halogen atom, and at least one carbon atom (—C—) of which may be substituted with —O—, —S—, or —P—; Z represents -O- or -N(-H)-. The resulting article is coated with a polymer material crosslinked with a crosslinked structure represented by the formula (2). From the viewpoint of easily increasing the hydrophilicity of the copolymer, Z in formula (2) is preferably -N(-H)-. R in formula (2) 6 Regarding R in Eq. (3), 6 The same applies to the above.

[0061] Hydroxyl groups are generated upon ring-opening of the cyclic carbonate structure in the structural unit (A) of the coating agent. Therefore, when the substrate is, for example, a metal component having hydroxyl groups on its surface, the hydroxyl groups generated upon ring-opening of the cyclic carbonate structure form hydrogen bonds with the hydroxyl groups on the surface of the metal component. As a result, the formation of a hydrophilic coating allows the hydrophilic coating to adhere well to the substrate. Furthermore, urethane bonds are formed upon ring-opening of the cyclic carbonate structure in the structural unit (A) of the coating agent. Therefore, for example, when the substrate surface is formed of a urethane resin, the urethane bonds formed upon ring-opening of the cyclic carbonate structure and the urethane structure on the substrate surface are compatible. As a result, the formation of a hydrophilic coating allows the hydrophilic coating to adhere well to the substrate. Thus, after the coating agent is applied to the substrate, reactions that proceed on the substrate surface generate hydroxyl groups and urethane bonds on the substrate surface, facilitating interactions between the hydrophilic coating and the substrate surface, making it easier to achieve high adhesion.

[0062] (Goods) The present invention also provides an article coated with a cured film of the coating agent containing the copolymer of the present invention (excluding elongated medical devices and components thereof, such as catheters and guidewires), preferably an article coated with the polymer material described above. The method for coating an article with a cured film of the coating agent containing the copolymer of the present invention is not particularly limited, but examples include applying the coating agent of the present invention to the surface of the object to be coated and heating it. Articles coated with a cured film of the coating agent of the present invention have high hydrophilicity and high water resistance. Examples of such articles include those described below.

[0063] The coating agent of the present invention can be used on a wide range of surfaces, including optical components such as optical filters, eyeglass lenses, in-vehicle lenses, optical lenses, prisms, and beam splitters; mirrors; optical components used on the screen surfaces of displays such as liquid crystal displays, plasma displays, electroluminescence displays, and CRT displays, and projection televisions; automobile windows, bodies, and the like; exterior walls and window glass of buildings; aircraft fuselages and window glass; kitchens, bathrooms, toilets, and other wet areas; solar panels; touch panels such as liquid crystal display devices, and the inner walls of water pipes; the outer surface of inner wires constituting control cables, the inner surface of outer casings constituting control cables, and the bottoms of ships. The coating agent of the present invention may be applied by, for example, coating or mixing with, for example, the following: surfaces of marine materials such as aquaculture equipment; sensors; medical devices such as artificial hearts, artificial kidneys, and artificial blood vessels (excluding long medical devices such as catheters and guidewires and components thereof; i.e., the medical devices of the present invention are medical devices that are not long medical devices or components thereof); cosmetics used for skin care, makeup, hair care, hair styling, etc.; cosmetic tools and containers such as makeup puffs, makeup brushes, and compacts; colorants such as inkjet inks, pigment inks, and dye inks; fiber treatment agents for paper, fabric, etc.; polymer flocculants used in sewage treatment; surfactants used in cleaning agents, etc.; hydrophilic primers for electroplating, etc. In this case, high hydrophilicity and water resistance can be imparted to articles coated with a cured film of the coating agent of the present invention, and as a result, functions such as biocompatibility, antifouling properties, resistance to protein adhesion, resistance to cell adhesion, antifogging properties, resistance to pollen adsorption, resistance to airborne particulate adhesion, and resistance to virus adhesion can be imparted to the surface of the article.

[0064] The method for coating an article with a cured film of the coating agent containing the copolymer of the present invention is not particularly limited, and examples thereof include applying the above-mentioned coating agent of the present invention to a substrate such as the surface of an article to be coated, followed by heating. The article coated with the cured film of the coating agent of the present invention has high hydrophilicity and high water resistance.

[0065] The material constituting the substrate to be coated with the coating agent is not particularly limited and may be, for example, a metal or a polymeric material (resin). From the viewpoint of further improving the adhesion of the coating agent, it is preferable that the surface of the substrate contains at least one material selected from the group consisting of metal, a polymeric material having a group capable of forming a hydrogen bond, and polyurethane. For example, by applying and curing the aforementioned coating agent to a metal substrate, a substrate containing a polymeric material having a group capable of forming a hydrogen bond, or a polyurethane substrate, the adhesion between the resulting hydrophilic cured film (hydrogel layer) and the substrate can be further improved.

[0066] The metal constituting the metal substrate may be, for example, an element that forms a metallic bond, such as iron (Fe), chromium (Cr), nickel (Ni), molybdenum (Mo), cobalt (Co), titanium (Ti), tungsten (W), platinum (Pt), gold (Au), silver (Ag), or tin (Sn), either alone or in the form of an alloy. More specifically, stainless steel alloys, nickel-titanium alloys, cobalt-chromium alloys, platinum alloys, tungsten, or silver-tin alloys may be suitably used.

[0067] The "group capable of forming a hydrogen bond" may be any group containing a hydrogen atom and in which the hydrogen atom forms a covalent bond with an atom that is more electronegative than the hydrogen atom. Examples of the atom that forms a covalent bond with a hydrogen atom include an oxygen atom (O), a nitrogen atom (N), a sulfur atom (S), and a carbon atom (C). More specifically, examples of the "group capable of forming a hydrogen bond" include a hydroxyl group (-OH), an amino group (-NH), and an imino group (=NH). Furthermore, examples of the "polymer material having a group capable of forming a hydrogen bond" include polyvinyl alcohol (PVA) and modified polyolefin resins having a group capable of forming a hydrogen bond.

[0068] As the polyurethane substrate, a wide variety of synthetic resins having urethane bonds can be used. Specifically, for example, aromatic ether urethane, aromatic carbonate urethane, aromatic ester urethane, aliphatic ether urethane, aliphatic carbonate urethane, aliphatic ester urethane, polyhydroxyurethane, urea urethane partially containing urea bonds, etc. can be used. In particular, aromatic ether urethane and polyhydroxyurethane are preferably used because of their superior flexibility, reactivity, and adhesion.

[0069] A cured film of a coating agent containing the copolymer of the present invention has high hydrophilicity and high water resistance. Therefore, the surface of an article coated with the cured film can maintain high hydrophilicity for a long period of time. Furthermore, in a preferred embodiment of the present invention, a cured film of a coating agent containing the copolymer of the present invention has the property of swelling in water, and the coating after swelling has high lubricity. Such a coating has very high biocompatibility when used in medical devices such as artificial hearts, artificial kidneys, and artificial blood vessels (particularly long medical devices and medical devices other than those components).

[0070] The thickness of the cured film and the swollen film is not particularly limited and may be set appropriately depending on the application, but can be, for example, about 1 μm to 1000 μm. [Example]

[0071] The present invention will be described in more detail below with reference to examples, but these examples are not intended to limit the scope of the present invention. In the examples, "%" and "parts" represent "% by mass" and "parts by mass", respectively, unless otherwise specified.

[0072] [Evaluation of copolymer] (water soluble) The copolymer solution was spread on a Teflon tray and then dried at 70°C for 12 hours or more using a commercially available vacuum dryer set at 0.1 KPa or less to obtain a copolymer solid. 90 parts of water was added to 10 parts of the obtained copolymer solid, and the mixture was stirred at room temperature for 30 minutes and then allowed to stand for 24 hours. The state of the solution was evaluated according to the following criteria. 〇: The solution is clear ×: There is residual residue in the solution, or the solution becomes cloudy

[0073] (Methanol soluble) The methanol solubility was evaluated in the same manner as in the evaluation of water solubility above, except that methanol was used instead of water.

[0074] (Soluble in ethanol) The ethanol solubility was evaluated in the same manner as in the evaluation of water solubility described above, except that ethanol was used instead of water.

[0075] (Soluble in isopropanol) The solubility in isopropanol was evaluated in the same manner as in the evaluation of water solubility described above, except that isopropanol was used instead of water.

[0076] (viscosity average molecular weight) The viscosity of a 1% solution of the copolymer was measured at 25°C using an Ubbelohde viscometer. The viscosity-average molecular weight of the copolymer was calculated by fitting the measured viscosity to a viscosity-molecular weight curve prepared using polyvinylpyrrolidone of known molecular weight.

[0077] (characteristic viscosity value, K) The viscosity (v1) of a 1% solution of the copolymer at 25°C was determined using an Ubbelohde viscometer in accordance with JIS Z 8803:2011. Similarly, the viscosity (v2) of the solvent used to dissolve the copolymer was determined. The relative viscosity value (v1 / v2) of the copolymer to the solvent was applied to the Fikentscher equation below to determine the K value. A lower K value indicates a lower molecular weight, and a higher K value indicates a higher molecular weight. K=(1.5 logη rel -1) / (0.15+0.003c)+(300clogη rel +(c+1.5clogη rel ) 2 ) 1 / 2 / (0.15c+0.003c 2 ) η rel: Relative viscosity of copolymer solution to diluent solvent c: Copolymer concentration in the copolymer solution (%)

[0078] [Evaluation of Coating Agents] (Method for evaluating film forming properties) The coating agent was applied to glass using a bar coater and then dried for 3 hours at 125°C to obtain a cured film (coating film). The appearance of the cured film was visually inspected and evaluated according to the following criteria. (Evaluation criteria) ◯: A uniform film was formed △: Cracks and / or white spots occurred on the film after drying, but the film was able to be formed ×: Film could not be formed

[0079] [Evaluation of Cured Film] (Water resistance 1 visual evaluation) 2.5 g of the coating agent was spread on a Teflon (registered trademark) coated tray (10 cm x 10 cm) and left to stand in an atmosphere at 125°C for 3 hours to obtain a cured product. The cured product was peeled off from the tray, and 2 parts of the peeled cured product were placed in a container, 98 parts of water was added, and the mixture was left to stand at room temperature for 24 hours. The state of the solution was then visually inspected and evaluated according to the following criteria: (Evaluation criteria) ◯: Hardened material remains, or remains in a swollen state. ×: The cured product is dissolved.

[0080] (Water resistance 2 analytical evaluation) The weight (w1) of an empty aluminum cup was measured, and 2.5 g of coating agent was spread on the aluminum cup. It was then left to stand in an atmosphere at 125°C for 3 hours to obtain a cured product. The weight (w2) of the aluminum cup with the cured product formed was measured, and 40 g of water was added. It was then left to stand at room temperature for 1 hour, after which the supernatant liquid was removed and the weight (w3) of the aluminum cup was measured. It was then dried under reduced pressure in an atmosphere at 100°C for 3 hours, after which the weight (w4) was measured, and the elution rate was calculated using the following formula. A lower elution rate indicates better water resistance. (calculation formula) Cured product dry weight=w2−w1 Dry weight after soaking=w4−w1 Elution rate (%) = (1-(dry weight of cured product - dry weight after immersion) / dry weight of cured product) x 100

[0081] (contact angle) The water contact angle of the coating film was measured by contacting a 1 μL water droplet with the coating piece prepared in the coating film formation evaluation, and after 5 seconds, the water contact angle was measured using the θ / 2 method using the "DMo-501" manufactured by Kyowa Interface Science Co., Ltd. and the image analysis software "FAMAS." The smaller the contact angle, the higher the hydrophilicity.

[0082] (Weight swelling rate) As in the above-mentioned "Water Resistance 2: Analytical Evaluation," w1 to w4 were measured, and the weight swelling ratio was calculated using the following formula: A larger weight swelling ratio indicates that the cured film can contain a larger mass of water, which indicates that the film swells more easily and has a higher gel-forming ability. (calculation formula) Cured product dry weight=w2−w1 Weight when swollen = w3 - w1 Dry weight after soaking=w4−w1 Weight swelling ratio (times) = swollen weight / dry weight after immersion

[0083] (Membrane strength) The samples used to evaluate film strength were prepared by dip coating the substrate, which consisted of a wire with a metal coil portion or a wire with a urethane coating layer on the surface of the metal coil portion, with the coating agents prepared in Examples 1 and 8, respectively (Examples 1a, 1b, 8a, and 8b). Comparative examples were also prepared using the same polymers used in Examples 1 and 8, but without the addition of a crosslinking agent (HMDA) (Comparative Examples 1c and 8c). After application of the coating agent, the substrate was dried for 1 hour in a hot air circulating oven at 120°C to obtain an evaluation sample. The resulting evaluation sample was placed underwater between a urethane roller (AXFM-D25-L15-V8-N, manufactured by Misumi Corporation) and a stainless steel plate (SUS304 plate, 30 × 30 mm). A load of 0.981 N was applied, and the resistance was measured when one end connected to a load cell was pulled out. The same measurement was carried out 50 times in succession, and the initial resistance value of the first measurement was compared with the resistance value of the 50th measurement to evaluate the film strength (film adhesion). The smaller the resistance value, the higher the film strength and the higher the durability during sliding.

[0084] (lubricity) To evaluate lubricity, the same samples as those used to evaluate film strength were used. Each sample was immersed in physiological saline, and then the coated area was rubbed with the fingertips to evaluate the feel according to the following criteria. The evaluation results are shown in Table 3 below. (Evaluation criteria) 〇: The surface is so slippery that it is difficult to hold the sample by hand. ×: The cured product flows out and is not smooth.

[0085] In the examples and comparative examples, the monomers shown in Table 1 below were used. [Table 1]

[0086] Example 1 (Synthesis of copolymer 1: GCMA-MAMCMB-M90G) In a reactor equipped with a condenser, thermometer, nitrogen inlet tube, and stirrer, GCMA, MAMCMB, and M90G were dissolved in a 70:30 water:ethanol mixture to a molar ratio of 10:40:50 and a total monomer concentration of 10%. Dissolved oxygen was removed by purging with inert gas, and the mixture was then heated to 50°C. At this point, 0.2 parts of 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride (Wako Pure Chemical Industries, Ltd. product name: VA-044) were added to initiate the polymerization reaction. The mixture was stirred for 4 hours while maintaining the temperature at 50°C, after which an additional 0.2 parts of VA-044 was added. The mixture was stirred for an additional 12 hours while maintaining the temperature at 50°C, yielding a solution of copolymer 1. The viscosity-average molecular weight of the resulting copolymer 1 was 140,000. (Preparation of Coating Agent 1) Copolymer 1, hexamethylenediamine (HMDA) as a crosslinking agent, and a mixed solvent of water:ethanol=70:30 were mixed in a mass ratio of 17:3:80 to obtain Coating Agent 1.

[0087] Example 2 (Synthesis of copolymer 2: GCMA-MAMCMB-M90G) In a reactor equipped with a condenser, thermometer, nitrogen inlet tube, and stirrer, GCMA, MAMCMB, and M90G were dissolved in ethanol at a molar ratio of 10:40:50, with a total monomer concentration of 45% by mass. Dissolved oxygen was then removed by purging with inert gas, and the mixture was heated to 70°C. At this point, 0.3 parts by weight of commercially available methyl azoisobutyrate was added to initiate the polymerization reaction. The mixture was stirred for 4 hours while maintaining the temperature at 70°C, and then 0.2 parts by weight of methyl azoisobutyrate was added. The mixture was stirred for an additional 12 hours while maintaining the temperature at 70°C, yielding a solution of copolymer 2. The viscosity-average molecular weight of the resulting copolymer 2 was 104,000. (Preparation of Coating Agent 2) Copolymer 2, hexamethylenediamine as a crosslinking agent, and ethanol as a solvent were mixed in a mass ratio of 17:3:80 to obtain coating agent 2.

[0088] Example 3 (Synthesis of Copolymer 3: GCMA-MAMCMB) A solution of copolymer 3 was obtained in the same manner as in Example 2, except that M90G was not used and the molar ratio of GCMA to MAMCMB was 10:90. The viscosity average molecular weight of the obtained copolymer 3 was 55,000. (Preparation of Coating Agent 3) Coating agent 3 was obtained in the same manner as in Example 2, except that copolymer 3 was used instead of copolymer 2.

[0089] Example 4 (Synthesis of Copolymer 4: GCMA-MAMCMB-M90G) A solution of copolymer 4 was obtained in the same manner as in Example 2, except that the molar ratio of GCMA, MAMCMB, and M90G was 20:40:40. The viscosity average molecular weight of the obtained copolymer 4 was 85,000. (Preparation of Coating Agent 4) Coating agent 4 was obtained in the same manner as in Example 1, except that copolymer 4 was used instead of copolymer 1.

[0090] Example 5 (Synthesis of Copolymer 5: GCMA-MAMCMB-M90G) A solution of copolymer 5 was obtained in the same manner as in Example 2, except that the molar ratio of GCMA, MAMCMB, and M90G was 10:30:60. The viscosity average molecular weight of the obtained copolymer 5 was 80,000. (Preparation of Coating Agent 5) Coating agent 5 was obtained in the same manner as in Example 1, except that copolymer 5 was used instead of copolymer 1.

[0091] Example 6 (Synthesis of Copolymer 6: GCMA-MAMCMB-M90G) A solution of copolymer 6 was obtained in the same manner as in Example 2, except that the molar ratio of GCMA, MAMCMB, and M90G was 10:50:40. The viscosity average molecular weight of the obtained copolymer 6 was 124,000. (Preparation of Coating Agent 6) Coating agent 6 was obtained in the same manner as in Example 1, except that copolymer 6 was used instead of copolymer 1.

[0092] Example 7 (Synthesis of Copolymer 7: GCMA-MAMCMB-M90G) A solution of copolymer 7 was obtained in the same manner as in Example 2, except that the molar ratio of GCMA, MAMCMB, and M90G was 10:60:30. The viscosity average molecular weight of the obtained copolymer 7 was 98,000. (Preparation of Coating Agent 7) Coating agent 7 was obtained in the same manner as in Example 1, except that copolymer 7 was used instead of copolymer 1.

[0093] Example 8 (Synthesis of Copolymer 8: GCMA-DMAAm) In a reactor equipped with a condenser, thermometer, nitrogen inlet tube, and stirrer, GCMA and DMAAm were dissolved in DMF at a molar ratio of 10:90 and a total monomer concentration of 30% by mass. Dissolved oxygen was then removed by purging with inert gas, and the temperature was then raised to 70°C. At this point, 0.15 parts by weight of commercially available methyl azoisobutyrate was added to initiate the polymerization reaction. The mixture was stirred for 4 hours while maintaining the temperature at 70°C, and then 0.3 parts by weight of methyl azoisobutyrate was added. The mixture was stirred for an additional 12 hours while maintaining the temperature at 70°C, yielding a solution of copolymer 8. The viscosity-average molecular weight of the resulting copolymer 8 was 66,000. (Preparation of Coating Agent 8) Copolymer 8, hexamethylenediamine as a crosslinking agent, and DMF as a solvent were mixed in a mass ratio of 17:3:80 to obtain coating agent 8.

[0094] Comparative Example 1 (Synthesis of copolymer a:DAAm-MAMCMB-HPMA) A solution of copolymer a was obtained in the same manner as in Example 1, except that DAAm was used as the crosslinkable monomer, MAMCMB and HPMA were used as the hydrophilic monomers, the molar ratio of DAAm to MAMCMB to HPMA was 10:40:50, and the copolymer was dissolved in a mixed solvent of water:ethanol = 80:20. The viscosity average molecular weight of the obtained copolymer a was 60,000. (Preparation of coating agent a) Copolymer a, adipic acid dihydrazide as a crosslinking agent, and a mixed solvent of water:ethanol=80:20 were mixed in a mass ratio of 9:1:90 to obtain coating agent a. Comparative Example 2 (Synthesis of copolymer b: DAAm-MAMCMB-M90G) A solution of copolymer b was obtained in the same manner as in Comparative Example 1, except that M90G was used instead of HPMA and the solvent was changed to water. The viscosity average molecular weight of the obtained copolymer b was 114,000. (Preparation of coating agent b) Copolymer b, adipic acid dihydrazide as a crosslinking agent, and water as a solvent were mixed in a mass ratio of 9:1:90 to obtain coating agent b.

[0095] Comparative Example 3 (Synthesis of copolymer c: DAAm-MAMCMB-DMAAm) A solution of copolymer c was obtained in the same manner as in Comparative Example 2, except that DMAAm was used instead of M90G and the solvent was changed to water. The viscosity average molecular weight of the obtained copolymer c was 200,000. (Preparation of coating agent c) Coating agent c was obtained in the same manner as in Comparative Example 2, except that copolymer c was used instead of copolymer b.

[0096] Comparative Example 4 (Synthesis of copolymer d: DAAm-MAMCMB-M90G) A solution of copolymer d was obtained in the same manner as in Comparative Example 1, except that DAAm, MAMCMB, and M90G were dissolved in water in a molar ratio of 10:40:50, with a total monomer concentration of 20%. The viscosity-average molecular weight of the obtained copolymer d was 168,000. (Preparation of coating agent d) Coating agent d was obtained in the same manner as in Comparative Example 2, except that copolymer d was used instead of copolymer b.

[0097] Comparative Example 5 (Synthesis of copolymer e: DAAm-MAMCMB-M90G) A solution of copolymer e was obtained in the same manner as in Comparative Example 4, except that a mixed solvent of water:ethanol = 80:20 was used instead of water as the solvent. The viscosity average molecular weight of the obtained copolymer e was 266,000. (Preparation of coating agent e) Coating agent e was obtained in the same manner as in Comparative Example 4, except that copolymer e was used instead of copolymer d.

[0098] Comparative Example 6 (Polymer f: Synthesis of GCMA homopolymer) A solution of polymer f was obtained in the same manner as in Example 2, except that GCMA was dissolved in ethanol to a concentration of 40 mass %. The viscosity average molecular weight of the obtained polymer f was 153,000. (Preparation of coating agent f) A coating agent f was obtained in the same manner as in Comparative Example 2, except that polymer f was used instead of copolymer b. However, since polymer f was not dissolved in the solvent, each evaluation could not be performed.

[0099] Comparative Example 7 (Polymer g: Synthesis of MAMCMB homopolymer) A solution of polymer g was obtained in the same manner as in Example 1, except that MAMCMB was dissolved in ethanol to a concentration of 10% by mass. The viscosity average molecular weight of the obtained polymer f was 95,000. (Preparation of coating agent g) A coating agent g was obtained in the same manner as in Comparative Example 6, except that polymer g was used instead of polymer f. However, since a part of polymer g was not dissolved in the solvent, it was not possible to perform various evaluations.

[0100] The monomer compositions of the copolymers obtained in the examples and comparative examples are shown in Table 2, and the results of evaluation of water solubility and the like are shown in Tables 3 and 4.

[0101] [Table 2]

[0102] [Table 3]

[0103] [Table 4]

[0104] (adhesion) <Evaluation of adhesion to metal substrates> The sample used to evaluate adhesion to metal substrates was a stainless steel plate, and the substrate was coated with the coating agent prepared in Example 1 in the same manner as the sample used to evaluate film strength to form a film. As a comparative example, a polyurethane film was formed by the dipping method using Pellethane 2360-80AE (manufactured by Lubrizol), a known medical polyurethane.

[0105] The adhesion to the metal substrate was evaluated by a cross-cut test (JIS K5600-5-6, 1999). Specifically, a grid-like cut was made in the formed coating at 1 mm intervals using a cutter knife, transparent adhesive tape was applied and then peeled off, and the state of the grid was observed to confirm the state of peeling of the coating.

[0106] In the coating formed using the coating agent of Example 1 of the present invention, no peeling of the coating was observed in any of the grids (evaluation result: 0 (no peeling)). In contrast, in the coating of the comparative example, peeling was observed widely in the area where the test was performed (evaluation result: 4 (large peeling)). As such, it was confirmed that the coating formed using the coating agent comprising the structural unit (A) having a cyclic carbonate structure and the structural unit (B) having a hydrophilic structure exhibits superior adhesion to metal substrates compared to the coating of the comparative example formed using a polyol resin and an isocyanate curing agent.

[0107] <Evaluation of adhesion to urethane substrate> The urethane substrate was a wire with a urethane coating layer on the surface of a metal coil, and the adhesion of the coating was evaluated. Specifically, the adhesion was compared between a coating formed from a copolymer having a structural unit (A) with a cyclic carbonate structure and a structural unit (B) with a hydrophilic structure, and a coating formed from a copolymer having a structural unit derived from a monomer containing an epoxy group instead of the structural unit (A) with a cyclic carbonate structure. The coating agent of Example 1 was used as the coating agent containing the copolymer having the structural unit (A) with a cyclic carbonate structure and the structural unit (B) with a hydrophilic structure. Furthermore, the copolymer having a structural unit derived from a monomer containing an epoxy group instead of the structural unit (A) with a cyclic carbonate structure was a copolymer consisting of 40 mol% MAMCMB, 50 mol% M90G, and 10 mol% 4HBAGE, which is a copolymer having a structural unit derived from 4-hydroxybutyl acrylate glycidyl ether (4HBAGE). The adhesion to the urethane substrate was evaluated using the same method as in the "Evaluation of Film Strength" described above.

[0108] FIG. 1 is an explanatory diagram showing the results of the adhesion evaluation. In FIG. 1, the horizontal axis represents the number of times the sample was pulled out and the resistance value was measured (number of slides), and the vertical axis represents the measured resistance value (slip resistance value). Here, three samples were prepared for each of a wire having a urethane coating layer coated with the coating agent of Example 1 (referred to as "structural unit (A)" in FIG. 1) and a coated guidewire coated with a copolymer having a structural unit derived from a monomer containing an epoxy group (referred to as "epoxy group-containing monomer-derived structural unit" in FIG. 1), and the above-mentioned test was performed for each sample. As shown in FIG. 1, it was confirmed that when a coating agent containing a structural unit (A) having a cyclic carbonate structure and a structural unit (B) having a hydrophilic structure was used, a hydrophilic coating exhibiting superior adhesion to a urethane substrate was obtained compared to when a coating agent containing a structural unit derived from a monomer containing an epoxy group and a structural unit (B) having a hydrophilic structure was used.

[0109] <Evaluation of catalytic activity under low-temperature conditions> Hydrophilic coatings were formed at relatively low temperatures using various copolymers containing modified structural units (B) with hydrophilic structures, and the catalytic activity of structural units (B) was evaluated. Specifically, copolymers containing structural units derived from N,N-dimethylacrylamide (DMAAm), N-vinylpyrrolidone (NVP), N-methacryloyloxyethyl-N,N-dimethylammonium-α-N-methylcarboxybetaine (CMB), and methoxyethyl acrylate (MEA) were prepared and evaluated. All copolymers contained structural units (A) with cyclic carbonate structures derived from (2-oxo-1,3-dioxolan-4-yl)methyl methacrylate (GCMA). Each copolymer contained 10 mol% structural units (A) and 90 mol% structural units (B). Of the copolymers described above, the copolymer having a structural unit derived from DMAAm as structural unit (B) was the same as the copolymer used in the previously described sample, and had a weight-average molecular weight of about 40,000. The copolymer having a structural unit derived from NVP as structural unit (B) had a weight-average molecular weight of about 55,000, the copolymer having a structural unit derived from CMB had a weight-average molecular weight of about 100,000, and the copolymer having a structural unit derived from MEA had a weight-average molecular weight of about 40,000.

[0110] The substrate on which the hydrophilic coating was formed was a wire with a urethane coating layer on the surface of the metal coil. After preparing each of the copolymers described above, the copolymer was dissolved in dimethylformamide to a concentration of 20 wt%. Then, immediately before application to the substrate, the coating agent containing the dissolved copolymer was mixed with a 5% ethanol solution of hexamethylenediamine (HMDA) as a crosslinker in a weight ratio of 5:3, and thoroughly dissolved. The coating agent containing the crosslinker was applied to the substrate by dip coating. After application, the coating agent was left at room temperature (26°C) for 1 hour, 2 hours, 3 hours, and 4 hours, and the change in viscosity was measured. The viscosity of each coating agent left on the substrate as described above was measured using a rotational vibration viscometer (VISCOMETER VM-10A-L, manufactured by Sansho Co., Ltd.).

[0111] Figure 2 is an explanatory diagram showing the viscosity change over time of coating agents containing polymers with different structural units (B). Figure 2 distinguishes between copolymers by indicating the type of structural unit (B). As shown in Figure 2, the viscosity increased over time only in coating agents containing DMAAm-derived structural units as the structural unit (B), confirming that crosslinking proceeds even at room temperature. Generally, when the structural unit (B) contains a betaine structure with a quaternary ammonium or an amide structure with a tertiary ammonium as the hydrophilic structure, these quaternary ammonium and tertiary ammonium are thought to act as catalysts for the crosslinking reaction of the coating agent. The results in Figure 2 confirm that, particularly when the structural unit (B) contains a DMAAm-derived structural unit, i.e., a positively charged quaternary nitrogen atom, the coating agent exhibits high activity in promoting the crosslinking reaction, even at low temperatures such as room temperature.

[0112] It was confirmed that an article coated with a cured product of a coating agent containing the copolymer of the present invention, which has at least a structural unit (A) having a cyclic carbonate structure and a structural unit (B) having a hydrophilic structure, has good water resistance and a small contact angle with water, which indicates that the article has high hydrophilicity. In contrast, in Comparative Examples 1 to 5, which contained other crosslinkable monomers instead of the structural unit (A) having a cyclic carbonate structure, water resistance was insufficient, and when measuring the contact angle, the coating piece dissolved when a 1 μL water droplet was brought into contact with the coating piece, making it impossible to measure the contact angle. Similarly, since the cured product dissolved in water, w3 ≒ w4 = w1, and therefore calculation of swelling was impossible. In Comparative Example 6, which only contained the structural unit (A), and Comparative Example 7, which only contained the structural unit (B), it was not possible to obtain a coating agent, and therefore each evaluation could not be performed.

Claims

1. A copolymer having at least a structural unit (A) having a cyclic carbonate structure and a structural unit (B) having a hydrophilic structure, wherein the hydrophilic structure is at least one structure selected from the group consisting of a betaine structure, an amide structure, an alkylene oxide structure, and a lactam structure, and the copolymer contains at least at least one structure selected from the group consisting of a betaine structure and an amide structure; the proportion of the structural unit (A) having a cyclic carbonate structure is 30 mol % or less based on the amount of all structural units in the copolymer, A copolymer, wherein the proportion of structural units having at least one structure selected from the group consisting of a betaine structure, an amide structure, an alkylene oxide structure, and a lactam structure in the copolymer is 60 mol% or more based on the amount of all structural units in the copolymer.

2. A copolymer having at least a structural unit (A) having a cyclic carbonate structure and a structural unit (B) having a hydrophilic structure, the copolymer being soluble in water, wherein the hydrophilic structure is at least one structure selected from the group consisting of a betaine structure, an amide structure, an alkylene oxide structure, and a lactam structure, and the proportion of the structural unit (B) contained in the copolymer is 60 mol % or more based on the amount of all structural units in the copolymer.

3. The copolymer according to claim 1 , wherein the structural unit (B) having a hydrophilic structure is electrically neutral.

4. 2. The copolymer according to claim 1, wherein the hydrophilic structure comprises a betaine structure having at least one atom selected from the group consisting of a positively charged quaternary nitrogen atom, a positively charged tertiary sulfur atom, and a positively charged quaternary phosphorus atom.

5. The betaine structure has the formula (1): 【Chemistry 1】 [In the formula, R １ represents a linear or branched alkylene group having 1 to 6 carbon atoms, R ２ each independently represents a linear or branched alkyl group having 1 to 4 carbon atoms, R ３ represents a linear or branched alkylene group having 1 to 4 carbon atoms, Y is -SO ３ － or -COO － represents * represents a bond. The copolymer according to claim 4, represented by the formula:

6. The copolymer according to claim 1 , wherein the structural unit (A) and the structural unit (B) are structural units derived from a (meth)acrylic monomer or a vinyl monomer.

7. A coating agent comprising the copolymer according to any one of claims 1 to 6 and a crosslinking agent.

8. 8. The coating agent according to claim 7, comprising at least a first agent and a second agent, wherein the first agent contains the copolymer according to any one of claims 1 to 6, and the second agent contains a crosslinking agent.

9. 8. The coating agent according to claim 7, wherein the crosslinking agent is at least one selected from the group consisting of polyamines and polyols.

10. An article (excluding elongated medical instruments and components thereof) coated with a cured film of the coating agent according to claim 7.

11. The copolymer having at least a structural unit (B) having a hydrophilic structure is represented by the following formula (2): -X １ -Z-R ４ -Z-X ２ - (2) [In the formula, X １ and X ２ are each independently —CH(OH)—CH(R ６ )—O—C(═O)—* and / or —CH(CH(R ６ )(OH))-O-C(=O)-*, * is bonded to Z in formula (2), R ４ represents a linear or branched alkylene group having 1 to 11 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms containing an alicyclic structure having 3 to 6 carbon atoms, or an aromatic group having 6 to 20 carbon atoms containing an aromatic ring structure having 6 to 10 carbon atoms, R ６ represents a hydrogen atom, or a linear or branched alkyl or alkenyl group having 1 to 4 carbon atoms, where R ６ at least one hydrogen atom of which may be substituted with a halogen atom, and at least one carbon atom (—C—) of which may be substituted with —O—, —S— or —P—; Z represents —O— or —N(—H)—. The article according to claim 10 , which is coated with a polymeric material crosslinked with a crosslinked structure represented by:

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