Resin composition, water-swellable film, article coated with water-swellable film, and method for producing water-swellable film

Abstract

The present invention relates to a resin composition comprising: a polymer (I) selected from the group consisting of polymers (a1) including a structural unit (i) having a betaine structure of an ester bond type and polymers (b1) including a structural unit (ii) having a betaine structure not of an ester bond type and a structural unit (iii) having a carboxyl group; an organic solvent having a 25°C Hansen solubility parameter in which the dispersion term δD is 10-24 MPa1 / 2, the polarity term δP is 5-19 MPa1 / 2, and the hydrogen-bonding term δH is 3-17 MPa1 / 2 and having a boiling point higher than 100°C; and water.

Description

[Technical Field]

[0001] The present invention relates to a resin composition, a water-swellable film, an article coated with the water-swellable film, and a method for producing the water-swellable film. [Background technology]

[0002] Polymers having a betaine structure are being considered for use as coating agents for biocompatible materials, for example. For example, Patent Document 1 describes a biocompatible polymer obtained by polymerizing a specific betaine monomer. Patent Document 2 describes a biocompatible material consisting of a polymer obtained by polymerizing an amino acid-type betaine monomer and a specific polymerizable monomer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-130194 [Patent Document 2] International Publication No. 2005 / 113620 Brochure [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-057745 Summary of the Invention [Problem to be solved by the invention]

[0004] Although polymers having the above-described structure have been known, the resin compositions described in Patent Documents 1 to 3 do not provide films with sufficient water-swelling properties. Therefore, an object of the present invention is to provide a resin composition that can form a film with excellent water-swelling properties. [Means for solving the problem]

[0005] In order to solve the above problems, the present inventors have investigated the structure of the copolymer contained in the resin composition, the composition of the resin composition, etc. As a result, they have found that a film having excellent water-swelling properties can be obtained by using a resin composition containing a polymer having a specific structure, a specific organic solvent, and water, and have completed the present invention.

[0006] That is, the present invention includes the following preferred embodiments. [1] A polymer (I) selected from the group consisting of a polymer (a1) containing a structural unit (i) having an ester-bonded betaine structure, and a polymer (b1) containing a structural unit (ii) having a non-ester-bonded betaine structure and a structural unit (iii) having a carboxyl group; In the Hansen solubility parameters at 25°C, the dispersion term δD is 10 to 24 MPa 1 / 2 , polarity term δP is 5~19MPa 1 / 2 , hydrogen bond term δH is 3 to 17 MPa 1 / 2 and an organic solvent having a boiling point higher than 100°C; water A resin composition comprising: [2] The ester-bonded betaine structure and / or the non-ester-bonded betaine structure may be 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, X represents -C(=O)-O- in an ester-bonded betaine structure, and represents -C(=O)-N(-H)- in a non-ester-bonded betaine structure; Y is -SO3 - or -COO - represents * represents a bond. The resin composition according to [1], represented by the formula: [3] The resin composition according to [1] or [2], wherein the polymer (a1) and / or the polymer (b1) further contains at least one structural unit having a hydrophilic structure. [4] The resin composition according to any one of [1] to [3], wherein the structural units (i) to (iii) are structural units derived from a (meth)acrylic monomer or a vinyl monomer. [5] The resin composition according to any one of [1] to [4], which contains 5% by mass to 30% by mass of the polymer (I) based on the total amount of the resin composition. [6] The resin composition according to any one of [1] to [5], which is a coating agent. [7] A water-swellable film comprising a polymer (II) selected from the group consisting of a polymer (a2) comprising a structural unit (iv) having an ester-bonded betaine structure and a structural unit (v) having a carboxyl group, and a polymer (b1) comprising a structural unit (ii) having a non-ester-bonded betaine structure and a structural unit (iii) having a carboxyl group. [8] An article (excluding long medical devices and components thereof) coated with the water-swellable film according to [7]. [9] A coating step of coating a substrate with the resin composition according to any one of [1] to [6]; A film-forming step in which the applied resin composition coating is heated to form a water-swellable film. [8] A method for producing the water-swellable membrane according to [7], comprising:

[10] The production method according to [9], wherein the film-forming step is a step of heating the applied coating film of the resin composition at a temperature higher than 90°C, and in the film-forming step, the polymer (a1) containing the structural unit (i) having an ester-bonded betaine structure is hydrolyzed to become the polymer (a2) containing the structural unit (iv) having an ester-bonded betaine structure and the structural unit (v) having a carboxyl group.

[11] The method according to

[10] , wherein the rate of hydrolysis of the polymer (a1) to the polymer (a2) is 5 mol % or more and 60 mol % or less. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a resin composition that can form a film having excellent water swelling properties. DETAILED DESCRIPTION OF THE INVENTION

[0008] 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.

[0009] The resin composition of the present invention comprises a polymer (I) selected from the group consisting of a polymer (a1) containing a structural unit (i) having an ester-bonded betaine structure and a polymer (b1) containing a structural unit (ii) having a non-ester-bonded betaine structure and a structural unit (iii) having a carboxyl group, and a polymer (I) having a dispersion term δD of 10 to 24 MPa in the Hansen solubility parameter at 25°C. 1 / 2 , polarity term δP is 5~19MPa 1 / 2 , hydrogen bond term δH is 3 to 17 MPa 1 / 2 and an organic solvent having a boiling point higher than 100°C, and water.

[0010] [Polymer (I)] The resin composition of the present invention contains a polymer (I) selected from the group consisting of polymer (a1) and polymer (b1). Polymer (a1) is a polymer containing a structural unit (i) having an ester-bonded betaine structure, and polymer (b1) is a polymer containing a structural unit (ii) having a non-ester-bonded betaine structure and a structural unit (iii) having a carboxyl group. The resin composition of the present invention may contain one or more types of polymer (a1), one or more types of polymer (b1), or one or more types of polymer (a1) and one or more types of polymer (b1). By containing polymer (I), the resin composition can impart water swelling properties to a film formed from the resin composition.

[0011] Polymer (a1) is a polymer containing a structural unit (i) having an ester-bonded betaine structure. A betaine structure refers to a structure in which a positive charge and a negative charge are present at non-adjacent positions within the same molecule, and no dissociable hydrogen is bonded to the positively charged atom, resulting in a neutral (uncharged) 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. A structural unit in which such a betaine structure is bonded to the polymer main chain via an ester bond is referred to as a structural unit (i) having an ester-bonded betaine structure.

[0012] Polymer (b1) is a polymer containing a structural unit (ii) having a betaine structure that is not an ester bond type and a structural unit (iii) having a carboxyl group. The betaine structure in structural unit (ii) also refers to a structure in which a positive charge and a negative charge are not adjacent to each other in the same molecule, and no dissociable hydrogen is bonded to the positively charged atom, resulting in a neutral (uncharged) structure overall. Examples of betaine structures include those described for structural unit (i). A structural unit in which such a betaine structure is bonded to the polymer main chain via a bond other than an ester bond, such as -N(-H)-, is referred to as a structural unit (ii) having a betaine structure that is not an ester bond type.

[0013] The betaine structures in the structural unit (i) having an ester-bonded betaine structure and the structural unit (ii) having a non-ester-bonded betaine structure are preferably betaine structures 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, from the viewpoint of easily increasing the water swelling property of the film, and more preferably betaine structures having a positively charged quaternary nitrogen atom.

[0014] In a preferred embodiment of the present invention, the ester-linked betaine structure and / or the non-ester-linked betaine structure has 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, X represents -C(=O)-O- in an ester-bonded betaine structure, and represents -C(=O)-N(-H)- in a non-ester-bonded betaine structure; Y is -SO3 - or -COO - represents * represents a bond. It is expressed as:

[0015] R 1 represents a linear or branched alkylene group having 1 to 6 carbon atoms. Examples of the linear or branched alkylene group having 1 to 6 carbon atoms 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. From the viewpoint of easily improving the water swelling of the water-swellable film formed from the resin composition of the present invention, R 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.

[0016] R 2are each independently a linear or branched alkyl group having 1 to 4 carbon atoms. 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, and an isobutyl group. From the viewpoint of easily improving water swelling properties, R 2 is 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.

[0017] R 3 represents a linear or branched alkylene group having 1 to 4 carbon atoms. 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. From the viewpoint of easily improving water swelling properties, R 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.

[0018] Y is -SO3 - or -COO - and preferably represents -COO - Represents.

[0019] The structural unit (iii) having a carboxyl group is not particularly limited as long as it is a structural unit having at least one carboxyl group, and may be a structural unit derived from a monomer having at least one carboxyl group. In a preferred embodiment of the present invention, the structural unit (iii) having a carboxyl group is preferably a structural unit in which a structure represented by -Z-COOH (wherein Z represents a single bond or an alkylene group having 1 to 3 carbon atoms, preferably a single bond) is bonded to the polymer main chain.

[0020] Polymer (a1) is a polymer containing the above structural unit (i), and may also contain, in addition to the structural unit (i), a structural unit (ii) having a non-ester bond type betaine structure, a structural unit (iii) having a carboxyl group, and further structural units different from the structural units (i) to (iii), such as a structural unit (vi) having a hydrophilic structure. Note that when a polymer contains, in addition to the structural unit (i), a structural unit (ii) having a non-ester bond type betaine structure and a structural unit (iii) having a carboxyl group, the polymer may be either polymer (a1) or polymer (b1).

[0021] The polymer (b1) is a polymer containing the structural unit (ii) having the above-mentioned non-ester bond type betaine structure and the structural unit (iii) having a carboxyl group. In addition to the structural unit (ii) and the structural unit (iii), the polymer (b1) may also contain other structural units different from these, such as a structural unit (vi) having a hydrophilic structure.

[0022] The proportion of the structural unit (i) contained in the polymer (a1) 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, from the viewpoint of easily increasing the water resistance of the formed film and easily increasing the adhesion of the formed film to the substrate. Moreover, the proportion of the structural unit (i) may be 100 mol% or less, for example, 90 mol% or less, 80 mol% or less, 70 mol% or less, 60 mol% or less, or 50 mol% or less.

[0023] When the polymer (a1) contains the structural unit (iii), the proportion of the structural unit (iii) is preferably 1 mol% or more, more preferably 3 mol% or more, and even more preferably 5 mol% or more based on the amount of all structural units, from the viewpoint of easily lowering the formation temperature when forming a water-swellable film, easily improving the water solubility of the polymer (a1), the water resistance of the formed film, and easily improving the adhesion of the formed film to the substrate. Moreover, the proportion of the structural unit (iii) may be, for example, 30 mol% or less, 20 mol% or less, 15 mol% or less, or 10 mol% or less.

[0024] The proportion of the structural unit (ii) contained in the polymer (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 increasing the water resistance of the formed film. The proportion of the structural unit (ii) may be, for example, 70 mol% or less, 60 mol% or less, 50 mol% or less, or 45 mol% or less.

[0025] The proportion of the structural unit (iii) contained in the polymer (b1) is preferably 1 mol% or more, more preferably 3 mol% or more, and even more preferably 5 mol% or more, based on the amount of all structural units, from the viewpoint of easily improving the adhesion of the formed film to the substrate. The proportion of the structural unit (ii) may be, for example, 30 mol% or less, 20 mol% or less, 15 mol% or less, or 10 mol% or less.

[0026] The polymer (a1) and / or polymer (b1) contained in the resin composition of the present invention preferably further contains at least one structural unit (vi) having a hydrophilic structure, from the viewpoint of easily improving the hydrophilicity and water swelling property of the formed film. The hydrophilic structure in the structural unit (vi) having a hydrophilic structure may be at least one structure selected from the group consisting of an amide structure, an alkylene oxide structure, and a lactam structure.

[0027] 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.

[0028] The alkylene oxide structure refers to a structure in which some of the carbon atoms forming the alkyl chain are substituted with oxygen. Such a structural unit (vi) is preferably -A-COOR 4[In the formula, A represents a single bond or an alkylene group having 1 to 3 carbon atoms, preferably a single bond, and R4 represents an alkyl group having 1 to 4 carbon atoms and a hydroxyl group bonded to at least one carbon atom], which is bonded to the main chain of a polymer. 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, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, polyethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, ethoxypolyethylene glycol (meth)acrylate, polyethylene glycol di(meth)acrylate, and 2-hydroxyethyl vinyl ether.

[0029] A lactam structure is a ring structure formed by dehydration condensation of a carboxyl 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.

[0030] When polymer (a1) and / or polymer (b1) further comprises structural unit (vi) having a hydrophilic structure, the proportion of structural unit (vi) is preferably 20 mol% or more, more preferably 30 mol% or more, and even more preferably 40 mol% or more, based on the total structural units of polymer (a1) and / or polymer (b1), from the viewpoint of easily improving the hydrophilicity and water swelling property of the formed film. Furthermore, when polymer (a1) and / or polymer (b1) further comprises structural unit (vi) having a hydrophilic structure, the proportion of structural unit (vi) is preferably 60 mol% or less, more preferably 55 mol% or less, and even more preferably 50 mol% or less, based on the total structural units of polymer (a1) and / or polymer (b1), from the viewpoint of easily improving the hydrophilicity and adhesion to the substrate of the formed film.

[0031] The above structural units (i) to (iii), as well as the structural unit (vi) and other structural units optionally contained therein, are derived from monomers having polymerizable groups copolymerizable with each other. Examples of such monomers include (meth)acrylic monomers or vinyl monomers. From the viewpoint of ease of production of copolymers, the above structural units are preferably structural units derived from (meth)acrylic monomers or vinyl monomers. The polymer (a1) may be a homopolymer or a copolymer so long as it contains the above structural units. When the polymer (a1) is a copolymer, it may be a random copolymer or a block copolymer, but is preferably a random copolymer. The polymer (b1) may be a random copolymer or a block copolymer so long as it contains the above structural units, but is preferably a random copolymer.

[0032] When the structural units (i) to (iii) are derived from a (meth)acrylic monomer, the structural units (i) and (ii) may be, for example, represented by the following formula (6): [ka] [In the formula, R 7a is a hydrogen atom or a methyl group, Ma represents an ester-bonded betaine structure for the structural unit (i) and a non-ester-bonded betaine structure for the structural unit (ii), and preferably represents the above formula (1). The structural unit may be derived from a monomer represented by the following formula:

[0033] As such a monomer, for the structural unit (i), for example, N-methacryloyloxyethyl-N,N-dimethylammonium-α-N-methylcarboxybetaine (GLBT), 3-{[2-(methacryloyloxy)ethyl]dimethylammonio}propionate (CEBMA), 3-{[2-(methacryloyloxy)ethyl]dimethylammonio}propane-1-sulfonate (SPBMA), etc. can be used, and N-methacryloyloxyethyl-N,N-dimethylammonium-α-N-methylcarboxybetaine (GLBT) is preferred.

[0034] Furthermore, for the structural unit (ii), for example, 2-{dimethyl[3-(2-methylprop-2-enamido)-propyl]ammonio}acetate (MAMCMB), 3-[(3-methacryloylamino-propyl)-dimethyl-ammonio]-propionate (MAMCEB), 3-[(3-acryloylamino-propyl)-dimethyl-ammonio]propane-1-sulfonate (SPBAM), 3-[(3-methacryloylamino-propyl)-dimethyl-ammonio]propane-1-sulfonate (SPBMAM), etc. can be used, with 2-{dimethyl[3-(2-methylprop-2-enamido)-propyl]ammonio}acetate (MAMCMB) being preferred.

[0035] The structural unit (iii) may be, for example, a structural unit derived from (meth)acrylic acid.

[0036] When the structural units (i) to (iii) are derived from a vinyl-based monomer, the structural units (i) and (ii) may be, for example, represented by the following formula (8): [ka] [In the formula, P a represents an ester-bonded betaine structure linked via a divalent linking group for the structural unit (i), and a non-ester-bonded betaine structure linked via a divalent linking group for the structural unit (ii), preferably a structure of the above formula (1) linked via a divalent linking group (e.g., an alkylene group having 1 to 3 carbon atoms). The structural unit may be derived from a monomer represented by the following formula:

[0037] The structural unit (iii) is, for example, a compound represented by the following formula (9): [ka] [In the formula, P b -Z b -COOH, Z b represents an alkylene group having 1 to 3 carbon atoms. The structural unit may be derived from a monomer represented by the following formula:

[0038] A preferred embodiment of the present invention will be described, in which the structural units (i) to (iii) are structures derived from a (meth)acrylic monomer. In this embodiment, the polymer (a1) containing the structural unit (i) is represented by the following formula (10): [ka] The polymer (b1) containing the structural units (ii) and (iii) may be a polymer containing at least a structural unit represented by the following formula (11): [ka] The polymer may be a polymer containing at least a structural unit represented by the following formula:

[0039] The above polymers (a1) and (b1) may further be represented by the following formula (12): [ka] In addition, R in the formulas (10) to (12) may further have a structural unit (vi) represented by the following formula:1 , R 2 , R 3 , and Y is R in formula (1). 1 , R 2 , R 3 , and Y are as defined above, and R 4 represents an alkyl group having 1 to 4 carbon atoms and a hydroxyl group bonded to at least one carbon atom, and R 7a represents a hydrogen atom or a methyl group, and A represents a single bond or an alkylene group having 1 to 3 carbon atoms, preferably a single bond.

[0040] The weight-average molecular weight of the polymer (I) contained in the resin composition 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 increasing the water swelling and water resistance of the water-swellable film obtained from the resin composition. 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 polymer (I) 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.

[0041] The viscosity average molecular weight of the polymer (I) contained in the resin composition 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 increasing the water swelling and water resistance of the water-swellable film obtained from the resin composition, and 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, from the viewpoint of solubility in solvents and ease of coating when used as a coating material. The viscosity average molecular weight of the polymer (I) may be measured, for example, using the method described in the Examples.

[0042] The method for producing the polymer (a1) is not particularly limited, but the polymer (a1) can be produced by polymerizing a monomer having a polymerizable group and the structural unit (i), optionally together with a monomer having a structural unit (ii), a structural unit (iii), a structural unit (vi) and / or other structural unit having a polymerizable group copolymerizable with each other.

[0043] The method for producing polymer (b1) is not particularly limited, and polymer (b1) can be produced by copolymerizing a monomer having a polymerizable group and structural unit (ii) with a monomer having a polymerizable group and structural unit (iii) copolymerizable with said monomer, optionally together with a monomer having structural unit (vi) and / or other structural units having polymerizable groups copolymerizable with each other.

[0044] When producing polymer (I), it is preferable to use at least one polymerization initiator from the viewpoint of promoting the polymerization reaction of the monomer components. Examples of the polymerization initiator 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, benzophenone derivatives, phosphine oxide derivatives, benzoketone derivatives, phenylthioether derivatives, azide derivatives, diazo derivatives, and photopolymerization initiators such as 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. 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 components.

[0045] Examples of polymerization methods for producing polymer (I) 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 a monomer component by solution polymerization, for example, the monomer component can be polymerized by dissolving the monomer component 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.

[0046] Examples of solvents used in the production of polymer (I) 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 hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as n-hexane; alicyclic hydrocarbons such as cyclohexane; acetates 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.

[0047] The amount of solvent used in the production of polymer (I) is usually preferably adjusted so that the concentration of the monomer components in the solution obtained by dissolving the monomer components in the solvent is about 10 to 80% by mass.

[0048] 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.

[0049] 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.

[0050] [Organic solvents] The resin composition of the present invention has a Hansen solubility parameter at 25°C of 10 to 24 MPa. 1 / 2 , polarity term δP is 5~19MPa 1 / 2 , hydrogen bond term δH is 3 to 17 MPa 1 / 2and contains at least one organic solvent having a boiling point higher than 100° C. The resin composition of the present invention may contain one organic solvent having the above-mentioned specific Hansen solubility parameter and boiling point, or may contain two or more organic solvents having the above-mentioned specific Hansen solubility parameter and boiling point, or may contain other organic solvents in addition to these organic solvents.

[0051] When the resin composition of the present invention contains the above-mentioned specific organic solvent, the water swelling of the water-swellable film formed from the resin composition of the present invention is more likely to be improved. The reason why the water swelling of the film is more likely to be improved when the above-mentioned specific organic solvent is contained is unclear, but it is thought to be due to the following mechanism, for example. The above-mentioned specific organic solvent is thought to be a solvent that has moderate incompatibility with polymer (I) and moderate miscibility with water. When the resin composition contains such an organic solvent, when the resin composition is applied to a substrate and the organic solvent and water are dried to remove them to obtain a coating film, water evaporates preferentially over the organic solvent. Therefore, as drying progresses, the proportion (concentration) of the organic solvent in the coating increases relatively, making the polymer (I) dissolved in water more likely to precipitate and aggregate than when the resin composition does not contain an organic solvent. This promotes the generation of electrostatic interactions between the betaine structure and carboxylic acid structure in polymer (I) and the formation of an ampholyte structure, as described below, which in turn facilitates the formation of a crosslinked structure capable of retaining water within the structure, making it easier to obtain a gel that exhibits water resistance and swelling properties. However, the present invention is not limited to this mechanism in any way.

[0052] In the Hansen solubility parameters of organic solvents at 25°C, the dispersion term δD is 10 to 24 MPa 1 / 2 , polarity term δP is 5~19MPa 1 / 2 , hydrogen bond term δH is 3 to 17 MPa 1 / 2indicates that the solvent has specific solubility characteristics. Specifically, an organic solvent having the above solubility parameter is considered to be a solvent that has moderate incompatibility with the polymer (I) and moderate miscibility with water. For example, the hydrogen bond term δH of the Hansen solubility parameter is 17 MPa. 1 / 2 If the hydrogen bond parameter ΔH is less than 3 and the polarity parameter ΔP is less than 5, the polymer (I) will not exhibit adequate miscibility with water and may even dissolve in water, making it difficult for a gel structure to form from the polymer (I). As a result, it will be difficult to improve the water resistance and swelling properties of the resulting film. Furthermore, if the polymer (I) is a polymer (a1) containing a structural unit (i) having an ester-bonded betaine structure, the hydrolysis of the polymer (a1) described below will be difficult to occur, making it difficult for a gel structure to form. If the hydrogen bond parameter ΔH is less than 3 and the polarity parameter ΔP is less than 5, the polymer (I) will not exhibit adequate miscibility with water and may even separate, making it difficult for a gel structure to form from the polymer (I).

[0053] Dispersion term δD is 10 to 24 MPa 1 / 2 and preferably 12 to 20 MPa 1 / 2 and more preferably 15 to 19 MPa 1 / 2 is.

[0054] The polarity term δP is 5~19MPa 1 / 2 and preferably 8 to 17 MPa 1 / 2 and more preferably 10 to 15 MPa 1 / 2 It comes out.

[0055] The hydrogen bond term δH is 3 to 17 MPa. 1 / 2 , and preferably 5 to 14 MPa 1 / 2 and more preferably 7 to 13 MPa. 1 / 2 is.

[0056] The Hansen solubility parameters of the organic solvents contained in the resin composition of the present invention may be values ​​listed in the calculation software Hansen Solubility Parameters in Practice (H SPiP, manufacturer: Charles M. Hansen). When the resin composition of the present invention contains one organic solvent, it is sufficient that the Hansen solubility parameter of the organic solvent is within the above range. When the resin composition of the present invention contains two or more organic solvents, it is sufficient that at least one of the organic solvents satisfies the above Hansen solubility parameter.

[0057] The Hansen solubility parameters of the organic solvent contained in the resin composition of the present invention are as follows: dispersion term δD, polar term δP, and hydrogen bond term δH √((δD-17) 2 +(δP-12) 2 +(δH-10) 2 )≦7 It is preferable that the following relationship is satisfied. The value calculated by this formula is preferably 7 or less. The above formula indicates that the organic solvent belongs to a Hansen sphere with an interaction radius R=7, with the central values ​​being dispersion term δD=17, polar term δP=12, and hydrogen bond term δH=10.

[0058] The organic solvent contained in the resin composition of the present invention has a boiling point higher than 100°C. The boiling point of the organic solvent is higher than 100°C, and from the viewpoint of easily increasing the water-swellability of the formed film, it is preferably 101°C or higher, more preferably 110°C or higher, even more preferably 115°C or higher, even more preferably 120°C or higher, particularly preferably 150°C or higher, and especially preferably 180°C or higher. Furthermore, from the viewpoint of the manufacturability and ease of availability of the resulting water-swellable film, the boiling point of the organic solvent contained in the resin composition of the present invention is preferably 205°C or lower. Note that when the resin composition of the present invention contains multiple types of organic solvents, at least one of the organic solvents should be an organic solvent having the above boiling point.

[0059] [water] The resin composition of the present invention contains at least water. Since the polymer (I) is usually a hydrophilic polymer and is soluble in water, it is believed that the polymer can be stably contained in the resin composition of the present invention by containing water as a solvent.

[0060] The content of polymer (I) contained in the resin composition of the present invention is not particularly limited, but from the viewpoint of easily imparting high hydrophilicity and water resistance to a water-swellable film obtained from the resin composition, it is preferably 1 to 90 mass %, more preferably 5 to 50 mass %, and even more preferably 8 to 20 mass %, based on the total amount of the resin composition of the present invention. The resin composition of the present invention may contain one type of polymer (I) or may contain two or more types of polymer (I).

[0061] The content of the organic solvent having the above-mentioned specific Hansen solubility parameter and boiling point contained in the resin composition of the present invention is not particularly limited, but from the viewpoint of easily imparting water resistance to a film, hydrogel, etc. obtained from the resin composition, it is preferably 1 to 90 mass %, more preferably 2 to 70 mass %, even more preferably 3 to 50 mass %, even more preferably 4 to 30 mass %, and particularly preferably 5 to 20 mass %, based on the total amount of the resin composition of the present invention.

[0062] The content of water in the resin composition of the present invention is not particularly limited, but is preferably 1 to 90 mass%, more preferably 10 to 95 mass%, even more preferably 20 to 90 mass%, still more preferably 40 to 85 mass%, and particularly preferably 50 to 80 mass%, based on the total amount of the resin composition of the present invention.

[0063] [Other ingredients] The resin composition of the present invention may contain other components in addition to the polymer (I), the specific organic solvent, and water. The other components may be selected appropriately depending on the intended use of the resin composition of the present invention, and examples thereof include fillers such as inorganic particles and organic particles, pigments, dyes, thickeners, surface tension agents, wettability modifiers, thixotropy regulators, surfactants, antifoaming agents, antioxidants, and UV absorbers. The amount of the other components may also be adjusted appropriately depending on the intended use of the resin composition of the present invention and the functions of the other components, and may be, for example, 0.01 to 99.99 mass% based on the weight of the resin composition of the present invention.

[0064] [Resin composition] The resin composition of the present invention containing the above components can be used as a water-swellable film-forming agent, a coating agent, etc. The resin composition of the present invention is preferably a coating agent. A water-swellable film can be formed on a substrate by applying the resin composition of the present invention to the substrate and heating it. Here, the heating results in the formation of a film that is insoluble in water and swells in water, due to the polymer (a1) and / or polymer (b1) contained in the resin composition of the present invention.

[0065] When the resin composition of the present invention contains a polymer (a1) containing a structural unit (i) having an ester-bonded betaine structure, the ester bond of the ester-bonded betaine structure in some of the structural units (i) repeatedly contained in the polymer (a1) is hydrolyzed by heating to form a structure having a carboxyl group. A relatively strong electrostatic interaction then occurs between the betaine structural portion of the structural unit (i) that remains unhydrolyzed and the hydroxyl group in the structure having a carboxyl group produced by hydrolysis, resulting in the formation of a crosslinked structure. This crosslinked structure is capable of retaining water within its network and possesses flexibility and stretchability, which is believed to result in the formation of a water-swellable film with high water swelling. The water-swellable film is believed to become a hydrogel upon swelling with water. This electrostatic interaction is stronger than the electrostatic interaction that can occur, for example, between the betaine structural portion and the hydroxyl group contained in another structural unit having a hydrophilic structure. Furthermore, ampholyte formation also occurs between the betaine structural portion of structural unit (i) that remains unhydrolyzed and the carboxyl group generated by hydrolysis, and it is thought that a crosslinked structure is also formed as a result.

[0066] The above will be further explained using, as an example, a polymer (a1') having, as structural unit (i), a structural unit derived from N-methacryloyloxyethyl-N,N-dimethylammonium-α-N-methylcarboxybetaine (also referred to as "GLBT") and, as structural unit (vi), a structural unit derived from hydroxypropyl methacrylate (also referred to as "HPMA").

[0067] Polymer (a1') obtained by copolymerizing GLBT and HPMA has a positively charged portion in the betaine structure and an -OH group in the hydrophilic structure, but the electrostatic interaction between them is weak, and when a film is formed from a resin composition containing such a polymer, a film having water-swelling properties cannot be obtained. [ka]

[0068] When such a polymer (a1') is heated at a certain temperature or higher (for example, a temperature exceeding 100°C) in the presence of a specific organic solvent and water contained in the resin composition of the present invention, some of the structural units derived from GLBT are hydrolyzed to form a structure having a carboxyl group, as shown in the following formula: [ka]

[0069] As a result, polymer (a2') is produced, which has the following structural units: Polymer (a2') is a polymer in which p mol % of the mm mol % GLBT-derived structural units contained in polymer (a1') have been hydrolyzed. Polymer (a2') contains m mol % GLBT-derived structural units, p mol % GLBT-derived structural units with carboxyl groups formed by hydrolysis, and 0 mol % HPMA-derived structural units. The electrostatic interaction between the positively charged moiety in the betaine structure of polymer (a2') and the -OH group of the carboxyl-containing structural unit is very strong, and it is believed that this electrostatic interaction forms a relatively strong crosslinked structure, resulting in a water-swellable film. While the diagram below shows interactions within the polymer, it is believed that similar interactions also occur between adjacent polymer chains. [ka]

[0070] It is also believed that the betaine structure portion and the carboxyl group portion are at least partially ampholyzed by a reaction such as that shown in the diagram below. [ka]

[0071] Therefore, it is believed that by heating the polymer (a1) containing the structural unit (i) having an ester-bonded betaine structure in the presence of a specific organic solvent and water contained in the resin composition of the present invention at a temperature exceeding 100°C, at which the ester bond moiety is hydrolyzed, the following interaction occurs, a crosslinked structure derived from ampholyte is formed, and a water-swellable film is formed. [ka]

[0072] When the resin composition of the present invention contains a polymer (b1) containing a structural unit (ii) having a non-ester bonded betaine structure and a structural unit (iii) having a carboxyl group, the structural unit (ii) having a non-ester bonded betaine structure is not a structure that is hydrolyzed under the heating conditions described above, so it is necessary to previously introduce the structural unit (iii) having a carboxyl group into the polymer (b1). The electrostatic interaction between the positively charged portion of the non-ester bonded betaine structure in the polymer (b1) and the carboxyl group portion is very strong, as described above for the polymer (a2), and it is believed that this electrostatic interaction results in a water-swellable film. It is also believed that at least a portion of these polymers is amphoterized.

[0073] [Water-swellable film] A water-swellable film having excellent swelling properties in water can be obtained by coating a substrate or the like with the resin composition of the present invention and drying it by heating. The present invention also provides such a water-swellable film. In the present invention, water-swellability refers to the increase in volume of a water-swellable film due to its absorption of water. As described above, water is believed to be exhibited by retaining water in the crosslinked structure formed by the polymer (I) in the water-swellable film. The water-swellable film of the present invention is exhibited not only by swelling with water (pure water) but also by an aqueous solution. The proportion of water in the aqueous solution is not particularly limited, but is preferably 90% or more, and more preferably 95% or more. Examples of such aqueous solutions include physiological saline (an aqueous solution containing at least about 0.9% by mass of sodium chloride) and a mixture of water and ethanol. The water-swellable film of the present invention includes not only a film swollen with water but also a film that can swell with water (i.e., a dry state). The water-swellable membrane of the present invention comprises a polymer (II) selected from the group consisting of a polymer (a2) comprising a structural unit (iv) having an ester-bonded betaine structure and a structural unit (v) having a carboxyl group, and a polymer (b1) comprising a structural unit (ii) having a non-ester-bonded betaine structure and a structural unit (iii) having a carboxyl group.

[0074] The water-swellable membrane of the present invention comprises: (1) a coating step of coating a substrate with the resin composition of the present invention; and (2) A film-forming step in which the applied resin composition coating is heated to form a water-swellable film. The present invention also provides a method for producing the water-swellable membrane of the present invention.

[0075] The coating step (1) is a step of applying the resin composition to a substrate.

[0076] The film-forming step (2) is a step of heating the applied resin composition coating to form a water-swellable film. The temperature at which the coating is heated is not particularly limited as long as it can remove at least a portion of the organic solvent and water contained in the resin composition.

[0077] When the polymer (I) contained in the resin composition is polymer (a1) and does not contain structural unit (iii) having a carboxyl group, the film-forming step is preferably a step of heating the applied coating film of the resin composition at a temperature higher than 90°C, more preferably a step of heating at a temperature higher than 100°C, in order to hydrolyze a portion of the ester-bonded betaine structure portion of polymer (a1) and form structural unit (iii) having a carboxyl group. Furthermore, in order to form structural unit (iii) having a carboxyl group and facilitate the formation of a crosslinked structure, the film-forming step is preferably a step of heating at a temperature lower than the boiling point of the organic solvent contained in the applied resin composition. In this case, in the film-forming step, polymer (a1) containing structural unit (i) having an ester-bonded betaine structure is hydrolyzed to form polymer (a2) containing structural unit (iv) having an ester-bonded betaine structure and structural unit (v) having a carboxyl group. The heating temperature and time may be adjusted as appropriate depending on the type of polymer, etc., but are preferably set under conditions such that the hydrolysis rate from polymer (a1) to polymer (a2) is preferably 5 mol % or more and 60 mol % or less. The hydrolysis rate from polymer (a1) to polymer (a2) is more preferably 10 to 45 mol %, and even more preferably 13 to 40 mol %. The hydrolysis rate is calculated using the following formula: Hydrolysis rate (%) = {(number of moles of ester-bonded betaine in polymer (a1) before hydrolysis - number of moles of ester-bonded betaine in polymer (a2)) / number of moles of ester-bonded betaine in polymer (a1) before hydrolysis} × 100

[0078] The ratio of the structural unit (iv) having an ester-bonded betaine structure to the structural unit (v) having a carboxyl group contained in the polymer (structural unit (iv):structural unit (v)) is preferably 90:10 to 10:90 (molar ratio), more preferably 87:13 to 60:40, and even more preferably 80:20 to 60:40. Furthermore, since the polymer (a2) is a polymer in which a portion of the ester-bonded betaine structure of the polymer (a1) has been hydrolyzed, the same description of the polymer (a1) above applies to the polymer (a2) with respect to the structure that is not changed by hydrolysis.

[0079] (Goods) The present invention also provides articles (excluding elongated medical devices such as catheters and guidewires and components thereof) and components thereof coated with the above-mentioned water-swellable film. The method for coating an article with the water-swellable film of the present invention is not particularly limited, but examples include applying the resin composition of the present invention to the surface of the object to be coated, etc., and heating, as described in the above-mentioned method for producing a water-swellable film of the present invention. Articles coated with the water-swellable film of the present invention have high water swelling properties and high water resistance. Examples of such articles include those described below.

[0080] The water-swellable film of the present invention can be used for, for example, 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; the bottoms of ships, The water-swellable film of the present invention may be applied to or mixed with the following: the surface 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 in 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 detergents, etc.; hydrophilic primers for electroplating, etc. In this case, high water swelling and water resistance can be imparted to articles coated with the water-swellable film 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.

[0081] The material constituting the substrate to be coated with the water-swellable film is not particularly limited, and may be, for example, a metal or a polymer material (resin).

[0082] 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.

[0083] The water-swellable film of the present invention has high water swelling and high water resistance. Therefore, the surface of an article coated with the gel formed by swelling the water-swellable film in water can maintain the gel film for a long period of time. Furthermore, the water-swellable film of the present invention has high lubricity after swelling in water. Such a film has very high biocompatibility when used in medical devices such as artificial hearts, artificial kidneys, and artificial blood vessels (but not long medical devices and their components).

[0084] The thickness of the water-swellable film is not particularly limited and may be set appropriately depending on the application, but may be, for example, about 1 μm to 1000 μm. Furthermore, the thickness of the gelled water-swellable film after swelling the water-swellable film in water may also be about 1 μm to 1000 μm.

[0085] The gelled water-swellable membrane (also referred to as a swollen gel membrane) obtained after swelling the water-swellable membrane in water contains a polymer (II) selected from the group consisting of polymer (a2) and polymer (b1). The swollen gel membrane is a hydrogel membrane formed by swelling the water-swellable membrane of the present invention with water, and its swelling degree is, for example, 180% to 900%, preferably 300% to 800%. The swelling degree is calculated as d2 / d1 × 100 (%), where d1 is the membrane thickness of the swollen gel membrane when thoroughly dried (e.g., dried to a water content of 0.1 wt % or less), and d2 is the membrane thickness of the swollen gel membrane when fully swollen. In this embodiment, the swollen gel membrane may be a physically crosslinked gel.

[0086] The weight swelling ratio of the swollen gel film is, for example, from 2 to 30 times, and preferably from 3 to 20 times. The weight swelling ratio is calculated as wb / wa, where wa is the weight of the swollen gel film when it is thoroughly dried (for example, dried to a water content of 0.1 wt % or less), and wb is the weight of the swollen gel film when it is fully swollen. [Example]

[0087] 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.

[0088] In the examples and comparative examples, the monomers shown in Table 1 below were used. [Table 1]

[0089] (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.

[0090] Example 1 (Copolymer 1: Synthesis of GLBT-HEMA) In a reactor equipped with a condenser, thermometer, nitrogen inlet tube, and stirrer, GLBT (Osaka Organic Chemical Industry Co., Ltd.) and HEMA (Osaka Organic Chemical Industry Co., Ltd.) were dissolved in water at a molar ratio of 50:50, with a total monomer concentration of 10%. Dissolved oxygen was removed by purging with inert gas, and the temperature was then raised to 50°C. At this point, 0.5 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 temperature was maintained at 50°C and the mixture was stirred for 4 hours. An additional 0.2 parts of VA-044 was then added, and the mixture was stirred for an additional 12 hours while maintaining the temperature at 50°C, yielding an aqueous solution of copolymer 1. The viscosity-average molecular weight of the resulting copolymer 1 was 100,000. (Preparation of Resin Composition 1) The aqueous solution of copolymer 1 obtained as described above and N-methylpyrrolidone (also referred to as "NMP") as a solvent were mixed in a mass ratio of 1:0.15 to obtain resin composition 1. The mass ratio of copolymer 1, organic solvent, and water in resin composition 1 was copolymer 1:organic solvent:water=8.7:13.0:78.3.

[0091] Example 2 (Synthesis of Copolymer 2: GLBT-HPMA) Except for using HPMA instead of HEMA, a solution of copolymer 2 was obtained in the same manner as in Example 1. The viscosity average molecular weight of the obtained copolymer 2 was 101,000. (Preparation of Resin Composition 2) The solution of copolymer 2 obtained as described above and NMP were mixed in a mass ratio of 1:0.15 to obtain resin composition 2. The mass ratio of copolymer 2, organic solvent, and water in resin composition 2 was copolymer 2:organic solvent:water=8.7:13.0:78.3.

[0092] Example 3 (Synthesis of Copolymer 3: GLBT-HPMA-MAA (47 / 50 / 3)) A solution of copolymer 3 was obtained in the same manner as in Example 1, except that GLBT, HPMA, and MAA were dissolved in water in a molar ratio of 47:50:3 and the total monomer concentration was 10%. The viscosity-average molecular weight of the obtained copolymer 3 was 100,000. (Preparation of Resin Composition 3) The solution of copolymer 3 obtained as described above and NMP were mixed in a mass ratio of 1:0.15 to obtain resin composition 3. The mass ratio of copolymer 3, organic solvent, and water in resin composition 3 was copolymer 3:organic solvent:water=8.7:13.0:78.3.

[0093] Example 4 (Synthesis of Copolymer 4: GLBT-HPMA-MAA (45 / 50 / 5)) A solution of copolymer 4 was obtained in the same manner as in Example 3, except that the number of moles of GLBT was 45 moles and the number of moles of MAA was 5 moles. The viscosity average molecular weight of the obtained copolymer 4 was 98,000. (Preparation of Resin Composition 4) The solution of copolymer 4 obtained as described above and NMP were mixed in a mass ratio of 1:0.15 to obtain resin composition 4. The mass ratio of copolymer 4, organic solvent, and water in resin composition 4 was copolymer 4:organic solvent:water=8.7:13.0:78.3.

[0094] Example 5 (Synthesis of Copolymer 5: GLBT-HPMA-MAA (43 / 50 / 7)) A solution of copolymer 5 was obtained in the same manner as in Example 3, except that the number of moles of GLBT was 43 moles and the number of moles of MAA was 7 moles. The viscosity average molecular weight of the obtained copolymer 5 was 100,000. (Preparation of Resin Composition 5) The solution of copolymer 5 obtained as described above and NMP were mixed in a mass ratio of 1:0.15 to obtain resin composition 5. The mass ratio of copolymer 5, organic solvent, and water in resin composition 5 was copolymer 5:organic solvent:water=8.7:13.0:78.3.

[0095] Example 6 (Synthesis of Copolymer 6: GLBT-HPMA-MAA (40 / 50 / 10)) A solution of copolymer 6 was obtained in the same manner as in Example 3, except that the number of moles of GLBT was 40 moles and the number of moles of MAA was 10 moles. The viscosity average molecular weight of the obtained copolymer 6 was 95,000. (Preparation of Resin Composition 6) The solution of copolymer 6 obtained as described above and NMP were mixed in a mass ratio of 1:0.15 to obtain resin composition 6. The mass ratio of copolymer 6, organic solvent, and water in resin composition 6 was copolymer 6:organic solvent:water=8.7:13.0:78.3.

[0096] Example 7 (Synthesis of copolymer 7:MAMCMB-HPMA-MAA(45 / 50 / 5)) A solution of copolymer 7 was obtained in the same manner as in Example 1, except that MAMCMB, HPMA, and MAA were dissolved in water:ethanol=80:20 so that the molar ratio was 45:50:5 and the total monomer concentration was 10%. The viscosity average molecular weight of the obtained copolymer 7 was 76,000. (Preparation of Resin Composition 7) The solution of copolymer 7 obtained as described above and NMP were mixed in a mass ratio of 1:0.15 to obtain resin composition 7. The mass ratio of copolymer 7, organic solvent, water, and ethanol in resin composition 7 was copolymer 7:organic solvent:water:ethanol=8.7:13.0:62.6:15.7.

[0097] Example 8 (Synthesis of copolymer 8MAMCMB-HPMA-MAA (43 / 50 / 7)) A solution of copolymer 8 was obtained in the same manner as in Example 7, except that the number of moles of MAMCMB was 43 moles and the number of moles of MAA was 7 moles. The viscosity average molecular weight of the obtained copolymer 8 was 67,000. (Preparation of Resin Composition 8) The solution of copolymer 8 obtained as described above and NMP were mixed in a mass ratio of 1:0.15 to obtain resin composition 8. The mass ratio of copolymer 8, organic solvent, water, and ethanol in resin composition 8 was copolymer 8:organic solvent:water:ethanol=8.7:13.0:62.6:15.7.

[0098] Example 9 (Synthesis of copolymer 9:MAMCMB-HPMA-MAA(40 / 50 / 10)) A solution of copolymer 9 was obtained in the same manner as in Example 7, except that the number of moles of MAMCMB was 40 moles and the number of moles of MAA was 10 moles. The viscosity average molecular weight of the obtained copolymer 9 was 67,000. (Preparation of Resin Composition 9) The solution of copolymer 9 obtained as described above and NMP were mixed in a mass ratio of 1:0.15 to obtain resin composition 9. The mass ratio of copolymer 9, organic solvent, water, and ethanol in resin composition 9 was copolymer 9:organic solvent:water:ethanol=8.7:13.0:62.6:15.7.

[0099] Comparative Example 1 (Synthesis of copolymer a:MAMCMB-HPMA) A solution of copolymer a was obtained in the same manner as in Example 1, except that MAMCMB and HPMA were dissolved in water:ethanol = 80:20 so that the molar ratio of MAMCMB and HPMA was 50:50 and the total monomer concentration was 10%. The viscosity average molecular weight of the obtained copolymer a was 55,000. (Preparation of Resin Composition a) The solution of copolymer a obtained as described above and NMP were mixed in a mass ratio of 1:0.15 to obtain resin composition a. The mass ratio of copolymer a, organic solvent, water, and ethanol in resin composition a was copolymer a:organic solvent:water:ethanol=8.7:13.0:62.6:15.7.

[0100] Comparative Example 2 The mass ratio of copolymer 7, organic solvent, water, and ethanol in resin composition 7 was copolymer 7:organic solvent:water:ethanol=8.7:13.0:62.6:15.7. (Synthesis of copolymer b: MAMCMB-HEMA) A solution of copolymer b was obtained in the same manner as in Example 1, except that MAMCMB and HEMA were dissolved in water:ethanol = 80:20 so that the molar ratio of MAMCMB and HEMA was 50:50 and the total monomer concentration was 10%. The viscosity average molecular weight of the obtained copolymer b was 79,000. (Preparation of Resin Composition b) The solution of copolymer b obtained as described above and NMP were mixed in a mass ratio of 1:0.15 to obtain resin composition b. The mass ratio of copolymer b, organic solvent, water, and ethanol in resin composition b was copolymer b:organic solvent:water:ethanol=8.7:13.0:62.6:15.7.

[0101] [Evaluation of copolymer] (water soluble) The copolymer solution was spread on a Teflon-coated tray and then dried for 12 hours or more in a commercially available vacuum dryer set at 70°C and 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

[0102] (degradability) The copolymer liquid was spread on a SUS tray and then dried at 120°C for 3 hours using a commercially available hot air dryer. The solid matter remaining in the SUS tray was collected and used for liquid chromatography to check for the presence or absence of betaine alcohol (decomposition product) (presence or absence of a peak). ○: Decomposition (hydrolysis) of the copolymer was confirmed. ×: Decomposition (hydrolysis) of the copolymer was not confirmed. The hydrolysis rate was 16 mol % in Example 2 and 0 mol % in Comparative Examples 1 and 2. When no hydrolysis was observed, the hydrolysis rate was 0%.

[0103] (Insoluble film formation) (Low-temperature formability 1) Evaluation of copolymer (without the addition of organic solvent (NMP)) The copolymer solution was spread on a Teflon (registered trademark)-coated tray and then dried for 3 hours at 85° C. using a commercially available hot air dryer. 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

[0104] (Low temperature formability 2) Evaluation of resin composition (with NMP added) 90 parts of water was added to 10 parts of the copolymer solid obtained in the same manner as in the evaluation method described above (Low-temperature formability 1), except that a resin composition was used instead of the copolymer. The mixture was stirred at room temperature for 30 minutes and then allowed to stand for 24 hours, and 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

[0105] (High-temperature formability) Evaluation of resin composition (with NMP added) The same procedure as in the evaluation method for low-temperature formability 1 described above was repeated except that a resin composition was used instead of the copolymer and the mixture was dried at 120°C instead of 85°C for 3 hours. 90 parts of water was added to 10 parts of the 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

[0106] [Evaluation of water-swellable membranes] (Water resistance 1 visual evaluation) 2.5 parts of the resin composition was spread on a Teflon (registered trademark) coated tray (10 cm x 10 cm) and left for 3 hours in an atmosphere at 125°C to obtain a cured product. The cured product was peeled off from the tray, and 2 parts of the peeled cured product was 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. Note that evaluation results shown in parentheses are predicted values. The same applies to other evaluations described below. (Evaluation criteria) ◯: The cured product remains in a swollen state. ×: The cured product is dissolved or remains in an unswollen state.

[0107] (Water resistance 2 analytical evaluation) The weight (w1) of an empty aluminum cup was measured, and 2.5 g of the resin composition was spread into the aluminum cup. This was then left to stand for 3 hours in an atmosphere at 125°C 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. This 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. This 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 higher 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

[0108] (Water swelling 1 visual evaluation) Two parts of the cured product obtained in the same manner as in Water Resistance 1 above were placed in a container, 98 parts of water were 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) ◯: The cured product remains in a swollen state. ×: The cured product is dissolved or remains in an unswollen state.

[0109] (Water swelling (gel forming) 2 analytical evaluation) The weight (w1) of an empty aluminum cup was measured, and 2.5 g of the resin composition was spread into the aluminum cup. The cup was then left to stand for 3 hours in an atmosphere at 125°C to obtain a water-swellable film. The weight (w2) of the aluminum cup with the water-swellable film formed thereon was measured, and 40 g of water was added. The cup 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. The aluminum cup was then dried under reduced pressure for 3 hours in an atmosphere at 100°C, after which the weight (w4) was measured, and the weight swelling ratio was calculated using the following formula: A higher weight swelling ratio indicates that the water-swellable film can contain a larger mass of water, which indicates easier swelling and better gel formation. (calculation formula) Weight when swollen = w3 - w1 Dry weight after soaking=w4−w1 Weight swelling ratio (times) = swollen weight / dry weight after immersion

[0110] (Slip resistance (gel adhesion)) The samples used to evaluate film strength were prepared by dip-coating a wire with a metal coil or a wire with a urethane coating layer on the surface of the metal coil as a substrate with each resin composition. Each resin composition was applied to the wire and then 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, sandwiched between a urethane roller (AXFM-D25-L15-V8-N, manufactured by Misumi Corporation) and a stainless steel plate (SUS304 plate, 30 x 30 mm), and a load of 0.981 N was applied. The resistance value was measured when one end connected to a load cell was removed. Similar measurements were performed 50 times consecutively, and the initial resistance value at the first measurement was compared with the resistance value at the 50th measurement to evaluate film strength (film adhesion). A lower resistance value indicates higher film strength and durability during sliding.

[0111] (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.

[0112] The monomer compositions of the copolymers obtained in the examples and comparative examples are shown in Table 2, and the results of evaluation of insoluble film forming properties and the like are shown in Table 3.

[0113] [Table 2]

[0114] [Table 3]

[0115] [Resin compositions 5-1 to 5-21] Resin compositions 5-2 to 5-16 were obtained in the same manner as in Example 5, except that in resin composition 5 containing copolymer 5 obtained in Example 5 (shown as resin composition 5-1 in Table 4), each solvent shown in Table 4 was used instead of NMP. The insoluble film-forming ability, water resistance, and water swelling property of these resin compositions were measured in the same manner as above. The results are shown in Table 4. Resin compositions 5-1, 5-5, and 5-7 to 5-10 in Table 4 are resin compositions according to the present invention.

[0116] [Table 4]

Claims

1. a polymer (I) selected from the group consisting of a polymer (a1) containing a structural unit (i) having an ester-bonded betaine structure, and a polymer (b1) containing a structural unit (ii) having a non-ester-bonded betaine structure and a structural unit (iii) having a carboxyl group; In the Hansen solubility parameter at 25°C, the dispersion term δD is 10 to 24 MPa. １／２ , polarity term δP is 5 to 19 MPa １／２ , hydrogen bond term δH is 3 to 17 MPa １／２ and an organic solvent having a boiling point greater than 100°C; water and The structural units (i) to (iii) are structural units derived from a (meth)acrylic monomer or a vinyl monomer, A resin composition, wherein the polymer (a1) and the polymer (b1) further contain a structural unit having at least one hydrophilic structure.

2. The ester-bonded betaine structure and / or the non-ester-bonded betaine structure may be represented by the formula (1): 【Chemical 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, X represents —C(═O)—O— in an ester-bonded betaine structure, and represents —C(═O)—N(—H)— in a non-ester-bonded betaine structure; Y is -SO ３ － or -COO － represents * represents a bond. The resin composition according to claim 1, wherein the resin composition is represented by the formula:

3. The resin composition according to claim 1, comprising 5% by mass to 30% by mass of the polymer (I) based on the total amount of the resin composition.

4. The resin composition according to any one of claims 1 to 3, which is a coating agent.

5. The polymer (II) is selected from the group consisting of a polymer (a2) containing a structural unit (iv) having an ester-bonded betaine structure and a structural unit (v) having a carboxyl group, and a polymer (b1) containing a structural unit (ii) having a non-ester-bonded betaine structure and a structural unit (iii) having a carboxyl group, The structural units (ii) to (v) are structural units derived from a (meth)acrylic monomer or a vinyl monomer, The polymer (a2) and the polymer (b1) further contain a structural unit having at least one hydrophilic structure. Water-swellable membrane.

6. An article (excluding elongated medical devices and components thereof) coated with the water-swellable film according to claim 5.

7. A coating step of coating a substrate with the resin composition according to any one of claims 1 to 3; and A film-forming step in which the applied resin composition coating is heated to form a water-swellable film. A method for producing the water-swellable membrane of claim 5, comprising:

8. 8. The method according to claim 7, wherein the film-forming step is a step of heating the applied coating film of the resin composition at a temperature higher than 90°C, and in the film-forming step, the polymer (a1) including the structural unit (i) having an ester-bonded betaine structure is hydrolyzed to become a polymer (a2) including the structural unit (iv) having an ester-bonded betaine structure and the structural unit (v) having a carboxyl group.

9. The method according to claim 8, wherein the rate of hydrolysis of the polymer (a1) to the polymer (a2) is 5 mol % or more and 60 mol % or less.

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