Hydrophilized composition

Abstract

The present invention addresses the problem of providing a hydrophilized composition that makes it possible to form a hydrophilized layer having good hydrophilicity, water-sliding properties, and hydrophilicity persistence. A hydrophilized composition according to the present invention comprises: a copolymer (A) having at least one structural unit (A1) that is selected from a structural unit (A11) which is derived from a polymerizable monomer having a carboxyl group and a structural unit (A12) which is derived from a polymerizable monomer having a hydroxyl group and a structural unit (A2) that is derived from a monomer in which a polyoxyalkylene group is bonded, via an ester bond, to a hydrocarbon group having a polymerizable double bond; and hydrophilic particles (B) containing a crosslinked polymer having a -COOR group (where R represents a hydrocarbon group, a hydrogen atom, an alkali metal atom, or ammonium) and a hydroxyl group.

Description

Hydrophilic treatment composition

[0001] The present invention relates to a hydrophilic treatment composition.

[0002] Heat exchangers have heat exchange plates, such as aluminum fins, that exchange heat between the heat transfer medium and the air. When the heat exchanger is in operation, moisture in the air can condense on the aluminum fin surface. If this condensed water turns into droplets and forms bridges between the fins, problems such as increased power consumption due to ventilation resistance and water droplet scattering can occur. To prevent such bridges caused by condensed water, the fin surface is often treated to be hydrophilic.

[0003] A known hydrophilic treatment involves applying a resin composition containing hydrophilic particles to the surface of a fin material to form a hydrophilic coating. Conventionally, inorganic particles such as silica and organic particles such as acrylic particles have been used as hydrophilic particles. Patent Documents 1 and 2 describe the use of hydrophilic crosslinked polymer microparticles composed of a copolymer of (a) 2 to 50 wt% of a hydrophilic monomer having a polymerizable double bond and a polyoxyalkylene chain or a polyvinylpyrrolidone chain, (b) 20 to 97 wt% of a (meth)acrylamide monomer, (c) 1 to 30 wt% of a crosslinkable unsaturated monomer, (d) 2 to 50 wt% of a carboxyl group-containing polymerizable unsaturated monomer, and (e) 0 to 50 wt% of other polymerizable monomers.

[0004] Furthermore, if the aluminum fin surface remains wet due to condensed water, it can cause various problems, such as reduced heat exchange efficiency, corrosion of the aluminum fin, bacterial growth, and frost formation. To solve these problems, it is important to facilitate drainage of condensed water from the aluminum fin surface, i.e., to increase the water sliding property of the aluminum fin surface. It is also known to treat the aluminum fin surface with a water-repellent treatment to improve the drainage property (water sliding property) of this condensed water. For example, Patent Document 3 discloses that a superwater- and oil-repellent heat exchanger component with excellent water sliding properties can be obtained by providing a plurality of confetti-shaped protrusions made of silica or the like on the surface of a substrate, and then forming a water-repellent, oil-repellent, and antifouling thin film on the surface of the substrate with the confetti-shaped protrusions. Patent Document 4 also discloses that a heat exchanger component with excellent water repellency and water sliding properties can be obtained by applying a structure having a water-sliding water-repellent layer containing a polymer having a polyethyleneimine skeleton, a fluorine-containing compound, and silica to a substrate.

[0005] On the other hand, Patent Document 5 describes that by using a treatment agent obtained by blending a specific water-soluble resin (A), colloidal silica (B), organoalkoxysilane and / or its hydrolyzate (C), a crosslinking agent (D) capable of crosslinking with the water-soluble resin (A), and water (E) in a predetermined ratio as a surface treatment agent for a heat exchanger made of an aluminum-containing metal, it is possible to make the aluminum fin surface hydrophilic, thereby preventing bridging due to condensed water and also improving drainage properties.

[0006] Japanese Patent Application Laid-Open No. 9-87576 Japanese Patent Application Laid-Open No. 2000-328038 Japanese Patent Application Laid-Open No. 2013-92289 International Publication No. 2020 / 213485 International Publication No. 2014 / 147782

[0007] The present invention aims to solve the following first and / or second problems. (First Problem) Surface hydrophilicity (initial hydrophilicity) is sometimes required for a variety of applications, including but not limited to the hydrophilization of fin materials in heat exchangers and coatings applied to their surfaces. There are cases in which high hydrophilicity (initial hydrophilicity) of a coating film immediately after coating film formation and good drainage properties (water sliding) of droplets are required. Therefore, the first problem of the present invention is to provide a new hydrophilic treatment composition capable of forming a hydrophilized layer (for example, a coating film) with good hydrophilicity and water sliding properties.

[0008] (Second Objective) The hydrophilic coating film is required to have enhanced hydrophilicity immediately after formation (initial hydrophilicity) as well as to maintain this hydrophilicity. In particular, the fin material of a heat exchanger will, over the course of long-term use, repeatedly go through a wet state in which condensed water is present on the surface of the fin material and a dry state in which the condensed water evaporates. Therefore, a hydrophilic layer such as a hydrophilic coating film applied to the fin material of a heat exchanger may be required to maintain its hydrophilicity even after repeated adhesion and drying of condensed water. Therefore, a second object of the present invention is to provide a hydrophilization treatment composition capable of forming a hydrophilic layer (e.g., a coating film) that has good hydrophilicity maintenance even after repeated adhesion and drying of low-ion water such as pure water (hereinafter sometimes referred to as "after wet / dry cycles").

[0009] The present invention aims to solve at least one of the first and second problems, and in a preferred embodiment, aims to solve both the first and second problems.

[0010] As a result of extensive research aimed at solving the above problems, the present inventors have found that the combined use of a specific polymer and specific hydrophilic particles can enhance both hydrophilicity and water slippage, and further found that the combined use of the polymer and hydrophilic particles can enhance the persistence of hydrophilicity after wet / dry cycling.

[0011] That is, the present invention includes the following inventions. [1] A hydrophilic treatment composition characterized by comprising: a copolymer (A) having at least one structural unit (A1) selected from a structural unit (A11) derived from a polymerizable monomer having a carboxyl group and a structural unit (A12) derived from a polymerizable monomer having a hydroxyl group; and a structural unit (A2) derived from a monomer in which a polyoxyalkylene group and a hydrocarbon group having a polymerizable double bond are linked via an ester bond; and hydrophilic particles (B) containing a crosslinked polymer having a -COOR group (R represents a hydrocarbon group, a hydrogen atom, an alkali metal atom, or ammonium) and a hydroxyl group. [2] The hydrophilic treatment composition according to [1], in which the hydrocarbon group in the structural unit (A2) is an aliphatic hydrocarbon group. [3] The hydrophilic treatment composition according to [1] or [2], in which the structural unit (A2) is derived from a monomer represented by the following formula (1): In the formula, R １ represents a hydrogen atom or a methyl group. ２ represents an alkylene group having 2 to 4 carbon atoms. ３ represents a hydrogen atom or an alkyl group having 1 to 30 carbon atoms. n represents the average number of moles of oxyalkylene groups added, and represents 2 to 500. [4] The hydrophilic treatment composition according to any one of [1] to [3], further comprising a crosslinking agent. [5] The hydrophilic treatment composition according to [4], wherein the crosslinking agent is a crosslinking agent having two or more oxazoline groups per molecule. [6] The hydrophilic treatment composition according to any one of [1] to [5], wherein the crosslinked polymer contains a structural unit derived from a monomer (BAB1) having one or more —COOR groups, one or more hydroxyl groups, and one polymerizable group per molecule, and a structural unit derived from a monomer (BC) having two or more polymerizable groups per molecule. [7] The hydrophilic treatment composition according to [6], wherein the structural unit derived from the monomer (BAB1) is a structural unit represented by the following formula (2), and the structural unit derived from the monomer (BC) is a structural unit derived from a polyfunctional ethylenically unsaturated monomer: In formula (2), R １represents an alkyl group having 1 to 4 carbon atoms, a hydrogen atom, an alkali metal atom, or ammonium. [8] The crosslinked polymer has a structural unit represented by formula (2), wherein R １is an alkali metal atom or ammonium. [9] The hydrophilic treatment composition according to any one of [1] to [8], wherein the hydrophilic particles (B) are single-layer particles or particles with a core-shell structure containing the crosslinked polymer in the shell layer.

[10] The hydrophilic treatment composition according to any one of [1] to [9], wherein the volume-average particle diameter of the hydrophilic particles (B) is 10 nm to 10 μm.

[11] The hydrophilic treatment composition according to [1] to

[10] , wherein the structural unit (A11) derived from a polymerizable monomer having a carboxyl group is a structural unit derived from an unsaturated monocarboxylic acid or a salt thereof.

[12] The hydrophilic treatment composition according to

[11] , wherein the unsaturated monocarboxylic acid or a salt thereof is acrylic acid, methacrylic acid, or a salt thereof.

[13] The hydrophilic treatment composition according to any one of [1] to

[12] , wherein the structural unit (A12) derived from a polymerizable monomer having a hydroxyl group is a structural unit derived from a (meth)acrylic acid hydroxyalkyl ester.

[14] The hydrophilic treatment composition according to any one of [1] to

[13] , wherein the structural unit (A2) is a structural unit derived from polyethylene glycol mono(meth)acrylate, polyethylene / polypropylene glycol mono(meth)acrylate, methoxypolyethylene glycol mono(meth)acrylate, methoxypolyethylene / polypropylene glycol mono(meth)acrylate, methoxypolyethylene glycol monomethacrylate, or methoxypolyethylene glycol monoacrylate.

[15] The hydrophilic treatment composition according to any one of [1] to

[14] , wherein the content of the structural unit (A2) is 30 to 99 parts by mass per 100 parts by mass of the total of the structural unit (A1) and the structural unit (A2).

[16] The hydrophilic treatment composition according to any one of [1] to

[15] , wherein the total content of the structural unit (A1) and the structural unit (A2) is 70 to 100 parts by mass per 100 parts by mass of the copolymer (A).

[17] The hydrophilic treatment composition according to any one of [1] to

[16] , wherein the object to be hydrophilically treated is a fin of a heat exchanger.

[18] A heat exchanger fin having, on its surface, a hydrophilized layer formed thereon, the hydrophilized layer comprising: a copolymer (A) having at least one structural unit (A1) selected from the structural unit (A11) derived from a polymerizable monomer having a carboxyl group and the structural unit (A12) derived from a polymerizable monomer having a hydroxyl group; and a structural unit (A2) derived from a monomer in which a polyoxyalkylene group and a hydrocarbon group having a polymerizable double bond are linked via an ester bond; and hydrophilic particles (B) comprising a crosslinked polymer having a -COOR group (R represents a hydrocarbon group, a hydrogen atom, an alkali metal atom, or ammonium) and a hydroxyl group.

[19] The fin according to

[18] , wherein the thickness of the hydrophilized layer is 0.1 to 80 μm.

[0012] The present invention can achieve the following first and / or second effects. First effect: By using the hydrophilic treatment composition of the present invention, it is possible to impart hydrophilicity and water-slip property to the obtained hydrophilic layer. Second effect: By using the hydrophilic treatment composition of the present invention, it is possible to improve the hydrophilicity sustainability of the obtained hydrophilic layer after wet / dry cycles.

[0013] FIG. 1 is a schematic diagram showing a method for measuring the sliding angle.

[0014] [Hydrophilic Treatment Composition] The hydrophilic treatment composition of the present invention comprises: a copolymer (A) having at least one structural unit (A1) selected from a structural unit (A11) derived from a polymerizable monomer having a carboxyl group and a structural unit (A12) derived from a polymerizable monomer having a hydroxyl group; and a structural unit (A2) derived from a monomer in which a polyoxyalkylene group and a hydrocarbon group having a polymerizable double bond are linked via an ester bond; and hydrophilic particles (B) containing a crosslinked polymer having —COOR groups (R represents a hydrocarbon group, a hydrogen atom, an alkali metal atom, or ammonium) and a hydroxyl group.

[0015] The hydrophilic treatment composition of the present invention is able to exhibit excellent hydrophilic properties (initial hydrophilicity, sustained hydrophilicity after wet / dry treatment, and water sliding property) due to the combination of the carboxyl group and / or hydroxyl group contained in the structural unit (A1), as well as the polyoxyalkylene group that is ester-bonded to a specific hydrocarbon group contained in the structural unit (A2), and the specific hydrophilic particles (B).

[0016] The constitution of the hydrophilic treatment composition will be explained. [Structural Unit (A1)] The structural unit (A1) of the present invention is at least one selected from the structural unit (A11) derived from a polymerizable monomer having a carboxyl group and the structural unit (A12) derived from a polymerizable monomer having a hydroxyl group.

[0017] As used herein, a "structural unit derived from a polymerizable monomer" refers to a structural unit having the same structure as the structure formed by polymerizing a specified monomer, and typically has a structure in which the carbon-carbon double bond contained in the specified monomer is replaced with a carbon-carbon single bond and two bonds bonded to each carbon. Note that a structural unit derived from a specified monomer does not necessarily have to be a structural unit formed by actually polymerizing the specified monomer; even a structural unit formed by a method other than polymerizing the specified monomer (for example, a structural unit formed via a reaction such as hydrolysis or neutralization after polymerization) is included in the structural unit derived from the specified monomer, as long as it has the same structure as the structure formed by polymerizing the specified monomer.

[0018] [Structural Unit (A11) Derived from Polymerizable Monomer Having a Carboxyl Group]

[0019] Examples of the polymerizable monomer having a carboxyl group include a carboxyl group-containing monofunctional monomer and a salt of a carboxyl group-containing monofunctional monomer.

[0020] The number of carboxyl groups contained in the polymerizable monomer having a carboxyl group is preferably 1 to 3, and more preferably 1. Specific examples of the carboxyl group-containing monofunctional monomer include unsaturated monocarboxylic acids such as (meth)acrylic acid and crotonic acid; and unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid; among these, unsaturated monocarboxylic acids are preferred, and (meth)acrylic acid is more preferred.

[0021] Examples of the salt of the carboxyl group-containing monofunctional monomer include alkali metal salts of the carboxyl group-containing monofunctional monomer and ammonium salts of the carboxyl group-containing monofunctional monomer. Salts of unsaturated monocarboxylic acids are preferred, and salts of (meth)acrylic acid are more preferred. Specific examples of alkali metal atoms and ammonium atoms that form salts with the carboxyl group-containing monofunctional monomer in the salt of the carboxyl group-containing monofunctional monomer are as follows:

[0022] Examples of the alkali metal atom include lithium, sodium, and potassium, with sodium and potassium being preferred, and sodium being more preferred.

[0023] Ammonium is NH ４＋ The organic ammonium is not limited to, but includes organic ammonium. The organic ammonium includes tetraalkylammonium such as tetramethylammonium and tetrabutylammonium (preferably tetra C １－１０ ammonium (primary to tertiary ammonium) formed by protonating an amine. Examples of the amine include trialkylamines (preferably triC) such as trimethylamine, triethylamine, and tributylamine. １－１０ alkylamines); hydroxyalkylamines such as monoethanolamine, diethanolamine, and triethanolamine (preferably mono-, di-, or tri(hydroxy C １－１０ That is, ammonium includes NH ４＋ammonium, primary to quaternary ammonium, and tetraalkylammonium such as tetramethylammonium and tetrabutylammonium (preferably tetra C １－１０ trialkylammonium (preferably triC alkylammonium), trimethylammonium, triethylammonium, tributylammonium, etc. １－１０ hydroxyalkylammonium (preferably mono-, di- or tri(hydroxy C alkyl ammonium) such as monoethanolammonium, diethanolammonium, triethanolammonium, １－１０ alkyl)ammonium), or NH4+ is preferred.

[0024] [Structural Unit (A12) Derived from Polymerizable Monomer Having a Hydroxyl Group] The number of hydroxyl groups contained in the polymerizable monomer having a hydroxyl group is preferably 1 to 3, and more preferably 1. The polymerizable group contained in the polymerizable monomer having a hydroxyl group is preferably an ethylenically unsaturated bond-containing group such as a vinyl group, an allyl group, or a (meth)acryloyl group, and more preferably a (meth)acryloyl group.

[0025] Specific examples of polymerizable monomers having a hydroxyl group include (meth)acrylic acid hydroxyalkyl esters such as hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxy-1-methylethyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and hydroxypentyl (meth)acrylate; and hydroxyl group-containing ethers such as 3-(meth)allyloxy-1,2-dihydroxypropane and 1-allyloxy-3-butoxypropan-2-ol. Among these, (meth)acrylic acid C １－８ Hydroxyalkyl esters are preferred, and (meth)acrylic acid C １－４ Hydroxyalkyl esters are more preferred.

[0026] [Structural Unit (A2)] The structural unit (A2) of the present invention is a structural unit derived from a monomer in which a polyoxyalkylene group and a hydrocarbon group having a polymerizable double bond are linked via an ester bond.

[0027] [Polyoxyalkylene Group] The polyoxyalkylene group preferably has a structure represented by the following formula: In the formula, R ４ is C ｍ H ２ｍ The alkylene group may be either linear or branched, but is preferably linear. ４ may be the same or different in the b repeating units. m is preferably an integer of 2 to 4, more preferably 2 or 3, and even more preferably 2. Examples of oxyalkylene groups having 2 to 4 carbon atoms include oxyethylene groups, oxypropylene groups, and oxybutylene groups. b represents the average number of moles of oxyalkylene groups added, and is preferably 2 to 500, more preferably 5 to 300, and even more preferably 10 to 200. R ５ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Examples of the 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, a sec-butyl group, and a tert-butyl group. R ５ is preferably a hydrogen atom.

[0028] [Hydrocarbon Group Having a Polymerizable Double Bond] The hydrocarbon group having a polymerizable double bond has at least one polymerizable double bond in one molecule. The number of carbon atoms in the hydrocarbon group having a polymerizable double bond is not particularly limited, but may be 2 to 20, preferably 2 to 10, and more preferably 2 to 5. The hydrocarbon group having a polymerizable double bond may be linear, branched, or cyclic, and is preferably an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group, and more preferably an aliphatic hydrocarbon group.

[0029] Examples of the aliphatic hydrocarbon group having a polymerizable double bond include monosubstituted alkenes such as vinyl groups, as well as disubstituted alkenes and trisubstituted alkenes such as allyl groups.

[0030] Examples of the monomer in which a polyoxyalkylene group and a hydrocarbon group having a polymerizable double bond are linked via an ester bond include monoesters of (alkoxy)polyalkylene glycol and (meth)acrylic acid, monoesters of (alkoxy)polyalkylene glycol and maleic acid, diesters of (alkoxy)polyalkylene glycol and maleic acid, monoesters of (alkoxy)polyalkylene glycol and fumaric acid, diesters of (alkoxy)polyalkylene glycol and fumaric acid, monoesters of (alkoxy)polyalkylene glycol and itaconic acid, and diesters of (alkoxy)polyalkylene glycol and itaconic acid. In the case of a monofunctional monomer having multiple carboxyl groups, for example, a monoester of an unsaturated dicarboxylic acid such as maleic acid, fumaric acid, or itaconic acid with an (alkoxy)polyalkylene glycol, the monofunctional monomer has both a polyoxyalkylene group and a carboxyl group. In the present invention, however, a monofunctional monomer having both a polyoxyalkylene group and a carboxyl group is treated as a monomer in which a polyoxyalkylene group and a hydrocarbon group having a polymerizable double bond are linked via an ester bond, i.e., a monomer that forms the structural unit (A2).

[0031] The structural unit (A2) is preferably derived from a monomer represented by the following formula (1). In the formula, R １ represents a hydrogen atom or a methyl group. ２ represents an alkylene group having 2 to 4 carbon atoms. ３represents a hydrogen atom or an alkyl group having 1 to 30 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Examples of the 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, and a tert-butyl group. n represents the average number of moles of oxyalkylene groups added, and is preferably 2 to 500, more preferably 5 to 300, and even more preferably 10 to 200.

[0032] Examples of the monomer represented by the above formula (1) include polyethylene glycol mono(meth)acrylate, polyethylene / polypropylene glycol mono(meth)acrylate, methoxypolyethylene glycol mono(meth)acrylate, methoxypolyethylene / polypropylene glycol mono(meth)acrylate, methoxypolyethylene glycol monomethacrylate, and methoxypolyethylene glycol monoacrylate.

[0033] The copolymer (A) may have one or more structural units corresponding to the structural unit (A1) and one or more structural units corresponding to the structural unit (A2). For example, acrylic acid and methacrylic acid may be used as the polymerizable monomer having a carboxyl group, or an ester of polyalkylene glycols of different structures (different in the type of oxyalkylene group, the average number of moles of oxyalkylene groups added, etc.) with (meth)acrylic acid may be used as the monomer in which a polyoxyalkylene group and a hydrocarbon group having a polymerizable double bond are linked via an ester bond, or an ester of polyalkylene glycols of the same structure with acrylic acid and methacrylic acid may be used.

[0034] From the standpoint of further improving hydrophilicity, the content of the structural unit (A2) is preferably 30 to 99 parts by mass, more preferably 50 to 95 parts by mass, and even more preferably 55 to 95 parts by mass, per 100 parts by mass of the total of the structural unit (A1) and the structural unit (A2).

[0035] The total content of the structural unit (A1) and the structural unit (A2) is preferably 70 to 100 parts by mass, more preferably 75 to 100 parts by mass, and even more preferably 80 to 100 parts by mass, per 100 parts by mass of copolymer (A), and may even be 100 parts by mass.

[0036] The weight average molecular weight of the copolymer (A) is preferably 2,000 to 1,000,000, more preferably 3,000 to 500,000, and even more preferably 4,000 to 250,000. The weight average molecular weight is measured by GPC (gel permeation chromatography) under the conditions described in the examples.

[0037] The copolymer (A) may contain one or more structural units (hereinafter, "other structural units (A3)") derived from monomers having a carbon-carbon double bond (hereinafter, "other monomers") other than the structural units (A1) and (A2).

[0038] The other monomers are not particularly limited as long as they can be copolymerized with the structural units (A1) and (A2), and examples thereof include 3-(meth)allyloxy-2-hydroxypropanesulfonic acid, 2-(meth)allyloxyethylenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, p-styrenesulfonic acid, α-methyl-p-styrenesulfonic acid, vinylsulfonic acid, vinylsulfamic acid, (meth)allyl sulfonic acid, isoprenesulfonic acid, 4-(allyloxy)benzenesulfonic acid, Unsaturated sulfonic acids and salts thereof, such as 1-methyl-2-propene-1-sulfonic acid, 1,1-dimethyl-2-propene-1-sulfonic acid, 3-butene-1-sulfonic acid, 1-butene-3-sulfonic acid, 2-acrylamido-1-methylpropanesulfonic acid, 2-acrylamidopropanesulfonic acid, 2-acrylamido-n-butanesulfonic acid, 2-acrylamido-2-phenylpropanesulfonic acid, and 2-((meth)acryloyloxy)ethanesulfonic acid; N-vinyl lactams, such as N-vinylpyrrolidone Monomers: (meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, iso-nonyl (meth)acrylate, dodecyl (meth)acrylate, and stearyl (meth)acrylate; (meth)acrylamide, N-monomethyl(meth)acrylamide, N-monoethyl(meth)acrylamide, and N,N-dimethyl N-substituted or unsubstituted (meth)acrylamides such as (meth)acrylamide; vinylaryl monomers such as styrene, α-methylstyrene, vinyltoluene, indene, vinylnaphthalene, phenylmaleimide, and vinylaniline; alkenes such as ethylene, propylene, butadiene, isobutylene, and octene; vinyl carboxylates such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, and butyl vinyl ether; vinyl ethylene carbonate and its derivatives;Examples include unsaturated amines such as N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylamide, vinylpyridine, vinylimidazole, and salts or quaternized products thereof; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile;

[0039] The content of the structural unit (A3) derived from other monomers in the copolymer (A) is, for example, 40% by mass or less, preferably 30% by mass or less, more preferably 20% by mass or less or 10% by mass or less, and even more preferably 5% by mass or less or 3% by mass or less.

[0040] [Hydrophilic particles (B) containing a crosslinked polymer having a -COOR group (R represents a hydrocarbon group, a hydrogen atom, an alkali metal atom, or ammonium) and a hydroxyl group] The hydrophilic treatment composition further contains hydrophilic particles (B). By containing the copolymer (A) and the hydrophilic particles (B), it is possible to improve hydrophilicity, water sliding properties, and sustained hydrophilicity. The hydrophilic particles (B) may be used alone or in combination of two or more types.

[0041] The hydrophilic particles (B) are composed of particles (hereinafter sometimes simply referred to as "polymer particles") containing a crosslinked polymer having a -COOR group (R represents a hydrocarbon group, a hydrogen atom, an alkali metal atom, or ammonium) and a hydroxyl group. When the hydrophilic treatment composition contains the copolymer (A) and the hydrophilic particles (B), it becomes possible to exhibit excellent hydrophilic properties (initial hydrophilicity, water sliding property, sustained hydrophilicity after wet / dry cycles, etc.).

[0042] The hydrocarbon group represented by R may be an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a combination thereof.

[0043] Examples of the aliphatic hydrocarbon group include alkyl groups (preferably alkyl groups having 1 to 4 carbon atoms) such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl; alkenyl groups (preferably alkenyl groups having 2 to 6 carbon atoms) such as vinyl, n-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 1-pentenyl, 2-pentenyl, 2-methyl-1-butenyl, 2-methyl-2-butenyl, and 3-methyl-1-butenyl; and cycloalkyl groups (preferably cycloalkyl groups having 3 to 8 carbon atoms) such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, and 4-ethylcyclohexyl.

[0044] Examples of the aromatic hydrocarbon group include a phenyl group, a methylphenyl group, a dimethylphenyl group, a trimethylphenyl group, a 4-tert-butylphenyl group, and a naphthyl group, and preferably an aromatic hydrocarbon group having 6 to 10 carbon atoms.

[0045] Examples of groups that combine an aliphatic hydrocarbon group with an aromatic hydrocarbon group include aralkyl groups such as benzyl and phenethyl, and preferably aralkyl groups having 7 to 12 carbon atoms.

[0046] The hydrocarbon group represented by R is preferably an alkyl group, more preferably an alkyl group having 1 to 4 carbon atoms, even more preferably an alkyl group having 1 to 2 carbon atoms, and particularly preferably a methyl group.

[0047] Examples of the alkali metal atom represented by R include lithium, sodium, and potassium, with sodium and potassium being preferred, and sodium being more preferred.

[0048] The description of the ammonium represented by R, as well as examples and preferred examples thereof, are the same as those for the structural unit (A11), and therefore will not be repeated here.

[0049] The crosslinked polymer may have one or more types of -COOR groups. When the crosslinked polymer has one type of -COOR group, R is preferably a hydrogen atom, an alkali metal atom, or ammonium, and more preferably an alkali metal atom or ammonium. When the crosslinked polymer has multiple types of -COOR groups, R is preferably a combination of one or more selected from a hydrogen atom, an alkali metal atom, and ammonium with a hydrocarbon group (particularly, an alkyl group having 1 to 4 carbon atoms), and more preferably a combination of one or more selected from an alkali metal atom and ammonium with a hydrocarbon group (particularly, an alkyl group having 1 to 4 carbon atoms). The total proportion of R that are hydrogen atoms, alkali metal atoms, or ammonium, relative to 100 mol% of all Rs contained in the crosslinked polymer (hereinafter referred to as the ionization rate), is, for example, 20 to 100 mol%, preferably 40 to 100 mol%, and more preferably 50 to 100 mol%. Adjusting the ionization rate within the above range improves hydrophilic properties and water slip properties. The upper limit of the ionization rate may be 95 mol % or less, or may be 90 mol % or less.

[0050] The hydroxyl value of the crosslinked polymer is preferably 20 to 500 mgKOH / g, more preferably 40 to 480 mgKOH / g, and even more preferably 70 to 450 mgKOH / g. The hydroxyl value means the amount (mg) of potassium hydroxide having the same amount of substance as the amount of hydroxyl groups contained in 1 g of the crosslinked polymer. When the composition of the crosslinked polymer is known, the hydroxyl value can be calculated by determining the amount of hydroxyl groups contained in the monomer components used as raw materials for the crosslinked polymer. For example, taking a crosslinked polymer prepared by polymerizing a monomer component containing 1% by mass of 2-hydroxyethyl methacrylate as a hydroxyl group-containing monomer, the hydroxyl value of the crosslinked polymer can be calculated based on the following formula: [hydroxyl value of crosslinked polymer] = [0.01 (mass-based content of 2-hydroxyethyl methacrylate in the monomer component used as a raw material for the crosslinked polymer) / 130 (molecular weight of 2-hydroxyethyl methacrylate) × 1 (number of hydroxyl groups per molecule of 2-hydroxyethyl methacrylate)] × 56.1 (substance amount of potassium hydroxide) × 1000 = 4.3 mg KOH / g. Furthermore, if the composition of the crosslinked polymer is unknown, the hydroxyl value can also be determined by calculating the amount (mg) of potassium hydroxide (KOH) required to neutralize the acetic acid bonded to the hydroxyl groups when 1 g of the crosslinked polymer is acetylated in accordance with JIS K0070. The hydroxyl value of the crosslinked polymer can be easily adjusted by adjusting the amount of the hydroxyl-containing monomer contained in the monomer component used as the raw material for the crosslinked polymer.

[0051] The proportion of —COOR groups contained in the crosslinked polymer is preferably 10 to 300 mol, more preferably 30 to 200 mol, still more preferably 50 to 150 mol, and particularly preferably 80 to 120 mol, per 100 mol of hydroxyl groups contained in the crosslinked polymer.

[0052] The crosslinked polymer preferably contains a structural unit derived from a monomer having two or more polymerizable groups in one molecule. The monomer having two or more polymerizable groups in one molecule includes a monomer having two or more ethylenically unsaturated bonds, and the monomer having two or more ethylenically unsaturated bonds at the terminal, that is, CH ２ It is preferable that the polymerizable group is a monomer having two or more =C< groups. That is, the polymerizable group is preferably an ethylenically unsaturated bond-containing group such as a vinyl group, an allyl group, or a (meth)acryloyl group.

[0053] Specific examples of the monomer having two or more polymerizable groups in one molecule include the monomer (BA2), the monomer (BB2), the monomer (BAB2), and the monomer (BC) described below, and these specific examples are applicable. Among them, the monomer (BC) is preferred.

[0054] The content of the structural unit derived from a monomer having two or more polymerizable groups in one molecule is, for example, 0.01 to 70% by mass, preferably 0.01 to 35% by mass, more preferably 1 to 25% by mass, and even more preferably 5 to 20% by mass in the crosslinked polymer. By adjusting the content of the structural unit derived from a monomer having two or more polymerizable groups in one molecule to fall within the above range, the hydrophilicity sustaining effect and water slipping property tend to be further enhanced.

[0055] The crosslinked polymer is preferably a crosslinked polymer of any one of the following aspects 1 to 4, more preferably a crosslinked polymer of aspect 1, aspect 2, or aspect 4, and particularly preferably a crosslinked polymer of aspect 4. In the following aspects 1 to 4, R in the -COOR group is the same as above, and preferred aspects thereof are also the same. Aspect 1: A crosslinked polymer comprising a structural unit derived from a monomer having one or more -COOR groups and one polymerizable group in one molecule and no hydroxyl group (hereinafter referred to as monomer (BA1)), a structural unit derived from a monomer having one or more hydroxyl groups and one polymerizable group in one molecule and no -COOR group (hereinafter referred to as monomer (BB1)), and a structural unit derived from a monomer (BC) having two or more polymerizable groups in one molecule (hereinafter referred to as monomer (BC)). Aspect 2: A crosslinked polymer comprising a structural unit derived from a monomer (BA1) and / or a monomer having one or more -COOR groups and two or more polymerizable groups in one molecule but not having a hydroxyl group (hereinafter referred to as monomer (BA2)), and a structural unit derived from a monomer (BB1) and / or a monomer having one or more hydroxyl groups and two or more polymerizable groups in one molecule but not having a -COOR group (hereinafter referred to as monomer (BB2)), the crosslinked polymer comprising at least a structural unit derived from monomer (BA2) and / or monomer (BB2). Aspect 3: A crosslinked polymer comprising a structural unit derived from a monomer having one or more -COOR groups, one or more hydroxyl groups and two or more polymerizable groups in one molecule (hereinafter referred to as monomer (BAB2)). Aspect 4: A crosslinked polymer comprising a structural unit derived from a monomer having one or more -COOR groups, one or more hydroxyl groups, and one polymerizable group in one molecule (hereinafter, referred to as monomer (BAB1)), and a structural unit derived from monomer (BC).

[0056] The number of —COOR groups contained in one molecule of the monomer (BA1) is preferably 1 to 3, and more preferably 1. The polymerizable group contained in the monomer (BA1) is preferably an ethylenically unsaturated bond-containing group such as a vinyl group, an allyl group, or a (meth)acryloyl group, and more preferably a (meth)acryloyl group.

[0057] Examples of the monomer (BA1) include carboxyl group-containing monofunctional monomers, salts of carboxyl group-containing monofunctional monomers, (meth)acrylate monomers, etc. The carboxyl group-containing monofunctional monomers and salts of carboxyl group-containing monofunctional monomers are the same as the examples of the structural unit (A11), and preferred examples are also the same.

[0058] Specific examples of the (meth)acrylate monomer include (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate; (meth)acrylic acid aryl esters such as phenyl (meth)acrylate; and (meth)acrylic acid aralkyl esters such as benzyl (meth)acrylate. Among these, (meth)acrylic acid alkyl esters are preferred, and (meth)acrylic acid C1-10 alkyl esters are more preferred, and (meth)acrylic acid C １－４ Alkyl esters are more preferred.

[0059] The number of polymerizable groups contained in the monomer (BA2) is preferably 2 to 6, and more preferably 2. The polymerizable group contained in the monomer (BA2) is preferably an ethylenically unsaturated bond-containing group such as a vinyl group, an allyl group, or a (meth)acryloyl group, and more preferably a (meth)acryloyl group.

[0060] Examples of the monomer (BA2) include dimethyl 1-benzyl-3,4-divinyl-1H-pyrrole-2,5-dicarboxylate, 1,1'-[2-[(ethoxycarbonyl)oxy]-1,3-propanediyl]bis(2-methyl-2-propenoate), and the like.

[0061] The number of hydroxyl groups contained in one molecule of the monomer (BB1) is preferably 1 to 3, and more preferably 1. The polymerizable group contained in the monomer (BB1) is preferably an ethylenically unsaturated bond-containing group such as a vinyl group, an allyl group, or a (meth)acryloyl group, and more preferably a (meth)acryloyl group.

[0062] Examples of the monomer (BB1) include the hydroxyl group-containing polymerizable monomers of the structural unit (A12), and suitable examples are also the same.

[0063] The number of hydroxyl groups contained in one molecule of the monomer (BB2) is preferably 1 to 3, and more preferably 1. The number of polymerizable groups contained in one molecule of the monomer (BB2) is preferably 2 to 6, and more preferably 2. The polymerizable group contained in the monomer (BB2) is preferably an ethylenically unsaturated bond-containing group such as a vinyl group, an allyl group, or a (meth)acryloyl group, and more preferably a (meth)acryloyl group.

[0064] Specific examples of the monomer (BB2) include esters of polyols having n hydroxyl groups (n is an integer of 3 or more, preferably an integer of 3 to 6), such as pentaerythritol tri(meth)acrylate and dipentaerythritol penta(meth)acrylate, with 2 to n-1 (meth)acrylic acids, and divinyl compounds having hydroxyl groups as represented by the following formula:

[0065]

[0066] The number of polymerizable groups contained in the monomer (BC) is preferably 2 to 6, and more preferably 2. The polymerizable group contained in the monomer (BC) is preferably an ethylenically unsaturated bond-containing group such as a vinyl group, an allyl group, or a (meth)acryloyl group, more preferably a vinyl group or a methacryloyl group, and particularly preferably a vinyl group.

[0067] The monomer (BC) preferably has a molecular weight of 50 or more and 1,000 or less, and more preferably 100 or more and 400 or less.

[0068] The monomer (BC) is preferably a polyfunctional ethylenically unsaturated monomer having two or more ethylenically unsaturated bond-containing groups, such as a hydrocarbon cross-linkable monomer, a divinyl ether monomer, a diallyl ether monomer, or a polyvalent (meth)acrylic acid ester.

[0069] Examples of the hydrocarbon cross-linkable monomer include aromatic hydrocarbon cross-linkable monomers such as divinylbenzene, trivinylbenzene, divinylnaphthalene, divinyltoluene, and divinylxylene; alicyclic hydrocarbon cross-linkable monomers such as trivinylcyclohexane; and chain hydrocarbon cross-linkable monomers such as 1,3-butadiene.

[0070] Examples of the divinyl ether monomer include dialkylene glycol divinyl ethers such as diethylene glycol divinyl ether, dipropylene glycol divinyl ether, and dibutylene glycol divinyl ether (preferably diC １－４ alkylene glycol divinyl ether); polyalkylene glycol divinyl ethers such as polyethylene glycol divinyl ether, polypropylene glycol divinyl ether, and polybutylene glycol divinyl ether (preferably polyC １－４ The number of repeating alkylene glycol units in the polyalkylene glycol divinyl ether is not particularly limited, but is preferably 3 to 10, and more preferably 3 to 5.

[0071] Examples of the diallyl ether monomer include dialkylene glycol diallyl ethers such as diethylene glycol diallyl ether, dipropylene glycol diallyl ether, and dibutylene glycol diallyl ether (preferably, diC １－４ alkylene glycol diallyl ether); polyalkylene glycol diallyl ethers such as polyethylene glycol diallyl ether, polypropylene glycol diallyl ether, and polybutylene glycol diallyl ether (preferably polyC １－４The number of repeating alkylene glycol units in the polyalkylene glycol diallyl ether is not particularly limited, but is preferably 3 to 10, and more preferably 3 to 5.

[0072] Examples of polyhydric (meth)acrylic acid esters include (meth)acrylic acid diesters of mono-, di-, or polyalkylene glycols such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and neopentyl glycol di(meth)acrylate; (meth)acrylic acid triesters of polyols such as trimethylolpropane tri(meth)acrylate and pentaerythritol tri(meth)acrylate; (meth)acrylic acid tetraesters of polyols such as pentaerythritol tetra(meth)acrylate; (meth)acrylic acid pentaesters of polyols such as dipentaerythritol penta(meth)acrylate; and (meth)acrylic acid hexaesters of polyols such as dipentaerythritol hexa(meth)acrylate. Among these, polyvalent methacrylic acid esters such as methacrylic acid diesters of mono-, di-, or polyalkylene glycols, methacrylic acid triesters of polyols, methacrylic acid tetraesters of polyols, methacrylic acid pentaesters of polyols, and methacrylic acid hexaesters of polyols are preferred because they have high resistance to hydrolysis, prevent the elution of particle components such as hydrophilic components, and tend to enhance the hydrophilicity sustaining effect and / or water slipping property.

[0073] Among the polyfunctional ethylenically unsaturated monomers, hydrocarbon cross-linkable monomers and polyvalent (meth)acrylic acid esters are preferred. In particular, hydrocarbon cross-linkable monomers and polyvalent methacrylic acid esters are more preferred because they have high resistance to hydrolysis and tend to further enhance the hydrophilicity sustaining effect and / or water slipping property, aromatic hydrocarbon cross-linkable monomers and methacrylic acid diesters of mono-, di-, or polyalkylene glycols are even more preferred, and divinylbenzene is particularly preferred.

[0074] The number of —COOR groups contained in one molecule of the monomer (BAB1) is preferably 1 to 3, and more preferably 1. The number of hydroxyl groups contained in one molecule of the monomer (BAB1) is preferably 1 to 3, and more preferably 1. The polymerizable group contained in the monomer (BAB1) is preferably an ethylenically unsaturated bond-containing group such as a vinyl group, an allyl group, or a (meth)acryloyl group, and more preferably a (meth)acryloyl group.

[0075] The monomer (BAB1) is preferably a hydroxymethylacrylic acid-based monomer represented by the following formula:

[0076] [In the formula, R １ represents an alkyl group having 1 to 4 carbon atoms, a hydrogen atom, an alkali metal atom, or ammonium.

[0077] R in the above formula １ Examples of alkyl groups having 1 to 4 carbon atoms represented by the following formula are the same as those for the structural unit (A2). Among these, alkyl groups having 1 to 2 carbon atoms are preferred, and methyl groups are even more preferred.

[0078] R in the above formula １ The alkali metal atom and ammonium represented by the formula (I) are the same as those already exemplified, and the preferred embodiments thereof are also the same.

[0079] The number of -COOR groups contained in one molecule of the monomer (BAB2) is preferably 1 to 3, and more preferably 1. The number of hydroxyl groups contained in one molecule of the monomer (BAB2) is preferably 1 to 3, and more preferably 1. The number of polymerizable groups contained in one molecule of the monomer (BAB2) is preferably 2 to 6, and more preferably 2. The polymerizable group contained in the monomer (BAB2) is preferably an ethylenically unsaturated bond-containing group such as a vinyl group, an allyl group, or a (meth)acryloyl group, and more preferably a (meth)acryloyl group.

[0080] Specific examples of the monomer (BAB2) include methyl 3,4-diethenyl-5-(hydroxymethyl)-1-(phenylmethyl)1H-pyrrole-2-carboxylate, methyl 3-hydroxy-3-(2-propen-1-yl)-5-hexenoate, and the like.

[0081] The crosslinked polymer of Aspect 1 may contain one or more structural units derived from the monomer (BA1). The crosslinked polymer of Aspect 1 may contain one or more structural units derived from the monomer (BB1). The crosslinked polymer of Aspect 1 may contain one or more structural units derived from the monomer (BC). The content of the structural units derived from the monomer (BA1) in the crosslinked polymer of Aspect 1 is preferably 1 to 98.99% by mass, more preferably 10 to 90% by mass, and even more preferably 10 to 50% by mass. The content of the structural units derived from the monomer (BB1) in the crosslinked polymer of Aspect 1 is preferably 1 to 98.99% by mass, more preferably 10 to 90% by mass, and even more preferably 10 to 50% by mass. The content of structural units derived from the monomer (BC) (preferably a polyfunctional ethylenically unsaturated monomer) in the crosslinked polymer of Aspect 1 is preferably 0.01 to 70% by mass, more preferably 0.01 to 35% by mass, and even more preferably 5 to 20% by mass. In the crosslinked polymer of Aspect 1, the total content of structural units derived from the monomer (BA1), the structural units derived from the monomer (BB1), and the structural units derived from the monomer (BC) is preferably 20 to 100% by mass, more preferably 30 to 100% by mass, and even more preferably 50 to 100% by mass. The crosslinked polymer of Aspect 1 may further contain structural units derived from other monomers other than the monomer (BA1), the monomer (BB1), and the monomer (BC). Examples of the other monomer include, in addition to the monomer (BAB1), polyoxyalkylene group-containing ethylenically unsaturated monomers, styrene-based monomers, vinyl ester-based monomers, silane group-containing monomers, nitrogen atom-containing monomers, oxo group-containing monomers, fluorine atom-containing monomers, epoxy group-containing monomers, light-stabilizing monomers, and ultraviolet absorbing monomers, which will be described later.

[0082] The crosslinked polymer of Aspect 2 may contain one or more structural units derived from the monomer (BA1). The crosslinked polymer of Aspect 2 may contain one or more structural units derived from the monomer (BA2). The crosslinked polymer of Aspect 2 may contain one or more structural units derived from the monomer (BB1). The crosslinked polymer of Aspect 2 may contain one or more structural units derived from the monomer (BB2). The total content of the structural units derived from the monomer (BA2) and the structural units derived from the monomer (BB2) in the crosslinked polymer of Aspect 2 is preferably 0.01 to 70% by mass, more preferably 0.01 to 35% by mass, and even more preferably 5 to 20% by mass. In the crosslinked polymer of Aspect 2, the total content of the structural units derived from the monomer (BA1), the structural units derived from the monomer (BA2), the structural units derived from the monomer (BB1), and the structural units derived from the monomer (BB2) is preferably 20 to 100% by mass, more preferably 30 to 100% by mass, and even more preferably 50 to 100% by mass. The crosslinked polymer of Aspect 2 may further contain structural units derived from other monomers other than the monomer (BA1), the monomer (BA2), the monomer (BB1), and the monomer (BB2). Examples of the other monomer include a monomer (BC) not included in the monomer (BA2) and the monomer (BB2), a monomer (BAB1), and a monomer (BAB2), as well as a polyoxyalkylene group-containing ethylenically unsaturated monomer, a styrene-based monomer, a vinyl ester-based monomer, a silane group-containing monomer, a nitrogen atom-containing monomer, an oxo group-containing monomer, a fluorine atom-containing monomer, an epoxy group-containing monomer, a light-stabilizing monomer, and an ultraviolet absorbing monomer, which will be described later.

[0083] The crosslinked polymer of Aspect 3 may contain one type of structural unit derived from the monomer (BAB2) alone, or may contain two or more types. The content of the structural unit derived from the monomer (BAB2) in the crosslinked polymer of Aspect 3 is preferably 0.01 to 100 mass%, more preferably 5 to 70 mass%, and even more preferably 10 to 50 mass%. The crosslinked polymer of Aspect 3 may further contain a structural unit derived from a monomer other than the monomer (BAB2). Examples of the other monomers include monomer (BA1), monomer (BA2), monomer (BB1), monomer (BB2), monomer (BC), and monomer (BAB1), as well as polyoxyalkylene group-containing ethylenically unsaturated monomers, styrene-based monomers, vinyl ester-based monomers, silane group-containing monomers, nitrogen atom-containing monomers, oxo group-containing monomers, fluorine atom-containing monomers, epoxy group-containing monomers, light-stabilizing monomers, and ultraviolet absorbing monomers, which will be described later.

[0084] The crosslinked polymer of the present invention is preferably a crosslinked polymer of Aspect 4 containing a structural unit derived from monomer (BAB1) and a structural unit derived from monomer (BC), and particularly preferably a crosslinked polymer containing a structural unit derived from a hydroxymethylacrylic acid-based monomer represented by the above formula and a structural unit derived from a polyfunctional ethylenically unsaturated monomer. The crosslinked polymer of Aspect 4 may contain one type of structural unit derived from monomer (BAB1) alone, or two or more types. The crosslinked polymer of Aspect 4 may also contain one type of structural unit derived from monomer (BC) alone, or two or more types.

[0085] The structural unit derived from the hydroxymethylacrylic acid-based monomer represented by the above formula can be rephrased as a structural unit represented by the following formula (3). That is, among the crosslinked polymers of embodiment 4, a crosslinked polymer containing a structural unit represented by the following formula (3) and a structural unit derived from a polyfunctional ethylenically unsaturated monomer is particularly preferred.

[0086] [In formula (3), R １ represents an alkyl group having 1 to 4 carbon atoms, a hydrogen atom, an alkali metal atom, or ammonium.

[0087] R in the above formula (3) １ The alkyl group having 1 to 4 carbon atoms represented by the formula (I), the alkali metal atom, and ammonium are as already explained, and the preferred embodiments thereof are also the same.

[0088] In addition, R １ When R is an alkali metal atom, it is contained in the crosslinked polymer as an alkali metal salt of a carboxylic acid, １ When is ammonium, it is contained in the crosslinked polymer as an ammonium salt of a carboxylic acid.

[0089] The crosslinked polymer of the fourth aspect preferably has a plurality of structural units represented by formula (3), and R １ may be the same or different. When they are all the same, R １ is preferably a hydrogen atom, an alkali metal atom, or ammonium, and more preferably an alkali metal atom or ammonium. １ If there is a １ As for all R contained in the crosslinked polymer of aspect 4, a combination of at least one selected from a hydrogen atom, an alkali metal atom, and ammonium with an alkyl group having 1 to 4 carbon atoms is preferred, and a combination of at least one selected from an alkali metal atom and ammonium with an alkyl group having 1 to 4 carbon atoms is more preferred. １ R is a hydrogen atom, an alkali metal atom, or ammonium in 100 mol % １ The total ratio of (hereinafter referred to as ionization rate) is, for example, 20 to 100 mol%, preferably 40 to 100 mol%, and more preferably 50 to 100 mol%. By adjusting the ionization rate within the above range, hydrophilic properties and water slip properties are improved. The upper limit of the ionization rate may be 95 mol% or less, or may be 90 mol% or less.

[0090] The content of the structural unit derived from the monomer (BAB1) (particularly the structural unit represented by formula (3), the same applies hereinafter) in the crosslinked polymer of Aspect 4 is, for example, 5 to 99.9% by mass, preferably 10 to 99% by mass, more preferably 15 to 95% by mass, and even more preferably 15 to 90% by mass. In particular, from the viewpoint of further enhancing hydrophilic properties or achieving a better balance between hydrophilicity and water slip properties, the content of the structural unit derived from the monomer (BAB1) in the crosslinked polymer of Aspect 4 is preferably 45 to 99.9% by mass, more preferably 65 to 99% by mass, and even more preferably 75 to 95% by mass.

[0091] The structural unit represented by the formula (3) may be formed by a polymerization reaction of the hydroxymethylacrylic acid monomer represented by the formula, but may also be formed by other methods. １ is an alkyl group having 1 to 4 carbon atoms, and then a basic substance such as an alkali metal hydroxide, ammonia, or amine is added to hydrolyze the ester group, thereby forming a compound represented by the formula (3) above, １ After the hydrolysis, an acid may be added appropriately to neutralize the compound, thereby forming a structural unit of an alkali metal or an ammonium. １ may form a structural unit of a hydrogen atom.

[0092] The hydroxymethylacrylic acid monomer represented by the above formula may be one type or two or more types. When the crosslinked polymer of the above embodiment 4 contains two or more types of structural units represented by formula (3), it may be formed by polymerizing two or more types of hydroxymethylacrylic acid monomers represented by the above formula, and R １ The hydroxymethylacrylic acid monomer may be formed by polymerizing a hydroxymethylacrylic acid monomer represented by the above formula, in which R is an alkyl group having 1 to 4 carbon atoms, and then partially hydrolyzing the ester group or by hydrolyzing the ester group with two or more basic substances.

[0093] As described above, the crosslinked polymer of Aspect 4 has structural units derived from the monomer (BC), and preferably has structural units derived from a polyfunctional ethylenically unsaturated monomer. The crosslinked polymer of Aspect 4 may contain one type of structural unit derived from a polyfunctional ethylenically unsaturated monomer alone, or may contain two or more types. The polyfunctional ethylenically unsaturated monomer is as described above, and the preferred embodiments thereof are also the same.

[0094] The content of the structural units derived from the monomer (BC) (particularly, the polyfunctional ethylenically unsaturated monomer) in the crosslinked polymer of Aspect 4 is, for example, 0.01 to 70% by mass, preferably 0.01 to 35% by mass, more preferably 1 to 25% by mass, and even more preferably 5 to 20% by mass. By adjusting the content of the structural units derived from the monomer (BC) (particularly, the polyfunctional ethylenically unsaturated monomer) within the above range, the hydrophilicity sustaining effect and water slipping property tend to be further enhanced. Furthermore, the content of the structural units derived from the monomer (BC) (particularly, the polyfunctional ethylenically unsaturated monomer) in the crosslinked polymer of Aspect 4 may be 0.01 to 10% by mass, 0.02 to 8% by mass, or 0.04 to 6% by mass.

[0095] In the crosslinked polymer of Aspect 4, the content of the structural unit derived from monomer (BC) (particularly, a polyfunctional ethylenically unsaturated monomer) relative to 100 parts by mass of the structural unit derived from monomer (BAB1) (particularly, a structural unit represented by formula (3)) is preferably 0.1 to 36 parts by mass, more preferably 2 to 26 parts by mass, and even more preferably 6 to 21 parts by mass.

[0096] In the crosslinked polymer of Aspect 4, the total content of the structural units derived from monomer (BAB1) and the structural units derived from monomer (BC) (particularly, the total content of the structural units represented by formula (3) and the structural units derived from the polyfunctional ethylenically unsaturated monomer) is preferably 50 to 100% by mass, more preferably 70 to 100% by mass, and even more preferably 80 to 100% by mass. The upper limit of the total content may be 99.9% by mass or 99% by mass.

[0097] The crosslinked polymer of Aspect 4 may further contain one or more structural units derived from a polyoxyalkylene group-containing ethylenically unsaturated monomer. The inclusion of such structural units improves the dispersion stability of particles in the resin composition, thereby further improving hydrophilic properties. Furthermore, the inclusion of such structural units tends to further enhance water sliding properties.

[0098] Examples of the polyoxyalkylene group-containing ethylenically unsaturated monomer include compounds having a polyoxyalkylene group in which the number of repeating oxyalkylene units is two or more and an ethylenically unsaturated bond-containing group, and among these, a compound represented by the following formula (4) is preferred.

[0099] In formula (4), R ３１ represents a hydrogen atom or a methyl group, R ３２ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms; m represents an integer of 1 to 4; and n represents an integer of 2 to 20.

[0100] R ３１ is preferably a methyl group, and R ３２ As the alkyl group, an alkyl group having 1 to 4 carbon atoms is preferred.

[0101] R ３２ Examples of the alkyl group having 1 to 4 carbon atoms represented by R １ The alkyl group having 1 to 4 carbon atoms is the same as that described above. ３２ Examples of the aromatic hydrocarbon group having 6 to 20 carbon atoms represented by the formula (R) include a phenyl group which may have one or more alkyl groups having 1 to 10 carbon atoms (provided that the total number of carbon atoms is 20 or less), and a naphthyl group which may have one or more alkyl groups having 1 to 10 carbon atoms (provided that the total number of carbon atoms is 20 or less). Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group. Among these, an alkyl group having 4 to 10 carbon atoms is preferred, and a nonyl group is more preferred. R ３２is preferably a hydrogen atom, an alkyl group having 1 to 2 carbon atoms, or a phenyl group which may have an alkyl group having 1 to 10 carbon atoms, and more preferably a hydrogen atom, a methyl group, or a phenyl group which may have a nonyl group.

[0102] C in formula (4) ｍ H ２ｍ The structure represented by the formula (4) indicates an alkylene group, and the alkylene group may be linear or branched, but is preferably linear. ｍ H ２ｍ The structures represented by may be the same or different. ｍ H ２ｍ When the structure represented by -(C ｍ H ２ｍ O) n- is one or more -C ２ H ４ O— and one or more —C ３ H ６ A structure in which O- is bonded in any order is preferred.

[0103] m is preferably an integer of 2 to 4, more preferably 2 or 3, and even more preferably 2.

[0104] n is preferably an integer of 2 to 15, and more preferably an integer of 2 to 10.

[0105] When the crosslinked polymer of Aspect 4 contains structural units derived from a polyoxyalkylene group-containing ethylenically unsaturated monomer, the content thereof is preferably 0.1 to 30 mass %, more preferably 1 to 20 mass %, and even more preferably 3 to 15 mass %, in the crosslinked polymer of Aspect 4. Furthermore, the content of the structural units derived from the polyoxyalkylene group-containing ethylenically unsaturated monomer per 100 mass parts of the structural units derived from the monomer (BAB1) (particularly, the structural units represented by formula (3)) is preferably 0.2 to 30 mass parts, more preferably 2 to 20 mass parts, and even more preferably 5 to 16 mass parts. In addition, in the crosslinked polymer of Aspect 4, the total content of the structural units derived from monomer (BAB1), the structural units derived from monomer (BC), and the structural units derived from the polyoxyalkylene group-containing ethylenically unsaturated monomer (particularly the total content of the structural units represented by formula (3), the structural units derived from the polyfunctional ethylenically unsaturated monomer, and the structural units derived from the polyoxyalkylene group-containing ethylenically unsaturated monomer) is preferably 60 to 100% by mass, more preferably 80 to 100% by mass, and even more preferably 90 to 100% by mass. The upper limit of the total content may be 99.9% by mass or 99% by mass.

[0106] The crosslinked polymer of Aspect 4 may contain one or more structural units derived from a monomer having one polymerizable group such as a carbon-carbon double bond-containing group per molecule (hereinafter referred to as "other monomer") other than the structural unit derived from the monomer (BAB1), the structural unit derived from the monomer (BC), and the structural unit derived from the polyoxyalkylene group-containing ethylenically unsaturated monomer.

[0107] The other monomers are not particularly limited, and examples thereof include (meth)acrylic monomers, styrene monomers, carboxy group-containing monomers, salts of carboxy group-containing monomers, vinyl ester monomers, silane group-containing monomers, hydroxyl group-containing monomers, nitrogen atom-containing monomers, oxo group-containing monomers, fluorine atom-containing monomers, epoxy group-containing monomers, light-stabilizing monomers, and ultraviolet absorbing monomers.

[0108] In the present invention, examples of the (meth)acrylic monomer include (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate. Among these, (meth)acrylic acid C1-10 alkyl esters are preferred, and (meth)acrylic acid C1-5 alkyl esters are more preferred.

[0109] In the present invention, the styrene-based monomer may be styrene optionally having one or more substituents such as a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), an alkyl group (e.g., a C1-4 alkyl group such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, or a tert-butyl group). Specific examples of the styrene-based monomer include styrene, α-methylstyrene, p-methylstyrene, tert-butylstyrene, chlorostyrene, and vinyltoluene, with styrene being preferred among them.

[0110] The carboxyl group-containing monomer and the salt of the carboxyl group-containing monomer are the same as the examples of the carboxyl group-containing polymerizable monomer and the salt of the carboxyl group-containing monofunctional monomer in the structural unit (A11), and the preferred examples are also the same.

[0111] In addition, in the salt of the carboxyl group-containing monomer, specific examples of the alkali metal atom or ammonium that forms a salt with the carboxyl group-containing monomer are the above-mentioned R １ The examples and preferred embodiments are the same as those of the alkali metal atoms and ammonium represented by the following formula: Among these, salts of acrylic acid are preferred.

[0112] In the present invention, examples of the vinyl ester monomer include esters of saturated fatty acids such as vinyl acetate and vinyl propionate with vinyl alcohol, and among these, esters of C1-5 saturated fatty acids with vinyl alcohol are preferred.

[0113] Examples of the silane group-containing monomer in the present invention include alkoxysilyl group-containing silane coupling agents such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(methoxyethoxy)silane, γ-(meth)acryloyloxypropyltrimethoxysilane, and 2-styrylethyltrimethoxysilane; halogenated silyl group-containing silane coupling agents such as vinyltrichlorosilane; and silanol group-containing silane coupling agents such as γ-(meth)acryloyloxypropylhydroxysilane and γ-(meth)acryloyloxypropylmethylhydroxysilane.

[0114] In the present invention, the preferred examples of the hydroxyl group-containing monomer are the same as those of the polymerizable monomer having a hydroxyl group in the structural unit (A12), and therefore further explanation will be omitted.

[0115] In the present invention, examples of the nitrogen atom-containing monomer include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, dimethylaminoethyl(meth)acrylamide, N-vinylpyrrolidone, and (meth)acrylonitrile.

[0116] In the present invention, examples of the oxo group-containing monomer include ethylene glycol methoxy(meth)acrylate.

[0117] In the present invention, examples of the fluorine atom-containing monomer include (meth)acrylic acid fluorinated alkyl esters such as trifluoroethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, and octafluoropentyl (meth)acrylate. Among these, (meth)acrylic acid C1-10 fluorinated alkyl esters are preferred, and (meth)acrylic acid C1-5 fluorinated alkyl esters are more preferred.

[0118] In the present invention, examples of the epoxy group-containing monomer include glycidyl (meth)acrylate.

[0119] In the present invention, examples of the light stabilizing monomer include 2,2,6,6-tetramethylpiperidine-4-(meth)acrylate.

[0120] In the present invention, examples of the ultraviolet absorbing monomer include benzotriazole-based ultraviolet absorbing monomers and benzophenone-based ultraviolet absorbing monomers.

[0121] The other monomer is preferably a (meth)acrylic monomer, a styrene-based monomer, a carboxyl group-containing monomer, a salt of a carboxyl group-containing monomer, or a hydroxyl group-containing monomer, more preferably a (meth)acrylic acid alkyl ester, (meth)acrylic acid, a salt of (meth)acrylic acid, or a styrene-based monomer, even more preferably an acrylic acid alkyl ester, acrylic acid, or a salt of acrylic acid, and particularly preferably acrylic acid or a salt of acrylic acid. In particular, the total content of structural units derived from acrylic acid and structural units derived from salts of acrylic acid (particularly the content of structural units derived from salts of acrylic acid) in the crosslinked polymer of Aspect 4 may be 0 to 40% by mass, or may be 5 to 20% by mass.

[0122] The content of structural units derived from other monomers in the crosslinked polymer of Aspect 4 is, for example, 40% by mass or less, preferably 30% by mass or less, more preferably 20% by mass or less or 10% by mass or less, and even more preferably 5% by mass or less or 3% by mass or less.

[0123] The hydrophilic particles (sometimes referred to as polymer particles) may be entirely composed of the above-mentioned crosslinked polymer, or a portion of the polymer particles may be composed of the above-mentioned crosslinked polymer. That is, the polymer particles may have a single-layer structure or a multi-layer structure. When the polymer particles have a single-layer structure, it is preferable that the entire particle is composed of the above-mentioned crosslinked polymer, and when the polymer particles have a multi-layer structure, it is preferable that the outermost shell layer is composed of the above-mentioned crosslinked polymer. By adopting such a structure, desired hydrophilic properties and water-sliding properties can be imparted.

[0124] Adopting a multilayer structure, preferably a core-shell structure, for the polymer particles is also effective in further enhancing hydrophilicity and water-slip properties. For example, constructing the outermost layer, such as the shell, from the crosslinked polymer can impart high hydrophilicity to the particles and water-slip properties to the resulting tangible product. Meanwhile, reducing the hydrophilicity of the inner layer, such as the core, can impart low solubility and low swelling properties to the particles, thereby suppressing deterioration and elution of the resulting coating film (hydrophilized layer). Therefore, the core-shell structure can impart higher hydrophilicity (particularly initial hydrophilicity) and water-slip properties than a single layer. Furthermore, heat exchanger fin materials used in outdoor units and car air conditioners may be exposed to pollutants such as urban dust and carbon black contained in automobile exhaust gases, and the adhesion of such pollutants can lead to a decrease in the hydrophilicity of the coating film (hydrophilized layer). Adopting a multilayer structure, such as a core-shell structure, for the polymer particles tends to make it easier to remove pollutants adhering to the coating film (hydrophilized layer) surface.

[0125] When the polymer particles have a multilayer structure, the second polymer constituting the layer other than the outermost layer (for example, the core portion in the case of core-shell particles) is preferably different from the crosslinked polymer.

[0126] The second polymer preferably has one or more structural units composed of a non-aqueous monomer that does not have an acidic proton-containing group such as a carboxyl group, a hydroxyl group, a thiol group, or a silanol group, and does not have an amino group. This reduces the hydrophilicity of the inner layer, such as the core portion. The non-aqueous monomer is preferably a monomer composed of a hydrocarbon that may have one or more groups selected from an ester group, an ether group, an amide group, and a halogeno group, and more preferably a monomer composed of a hydrocarbon that may have an ester group.

[0127] Specific examples of the non-aqueous monomer include (meth)acrylic monomers, styrene monomers, vinyl ester monomers, oxo group-containing monomers, fluorine atom-containing monomers, epoxy group-containing monomers, etc. Examples of these (meth)acrylic monomers, styrene monomers, vinyl ester monomers, oxo group-containing monomers, fluorine atom-containing monomers, and epoxy group-containing monomers are the same as the monomers described above for the crosslinked polymer, and preferred aspects of each monomer are also the same.

[0128] The non-aqueous monomer is preferably a (meth)acrylic monomer or a styrene-based monomer, more preferably a (meth)acrylic acid alkyl ester or a styrene-based monomer, and even more preferably a (meth)acrylic acid C1-5 alkyl ester or styrene.

[0129] The content of the structural units derived from the non-aqueous monomer in the second polymer is preferably 40 to 99% by mass, more preferably 50 to 90% by mass, and even more preferably 60 to 80% by mass.

[0130] The second polymer preferably further contains one or more structural units derived from a polyfunctional ethylenically unsaturated monomer. This is expected to further enhance the initial hydrophilicity, sustained hydrophilicity, and water slippage of the coating film (tangible object) surface. Examples of the polyfunctional ethylenically unsaturated monomer include the same monomers as the polyfunctional ethylenically unsaturated monomers described for the crosslinked polymer. Among these, hydrocarbon crosslinkable monomers and polyvalent (meth)acrylic acid esters are preferred, aromatic hydrocarbon crosslinkable monomers and (meth)acrylic acid diesters of mono-, di-, or polyalkylene glycols are more preferred, and divinylbenzene is even more preferred.

[0131] The content of the structural units derived from the polyfunctional ethylenically unsaturated monomer in the second polymer is preferably 1 to 50% by mass, more preferably 10 to 45% by mass, and even more preferably 20 to 40% by mass. Furthermore, in the second polymer, the content of the structural units derived from the polyfunctional ethylenically unsaturated monomer per 100 parts by mass of the structural units derived from the non-aqueous monomer is preferably 10 to 70 parts by mass, more preferably 20 to 60 parts by mass, and even more preferably 20 to 50 parts by mass. Furthermore, in the second polymer, the total content of the structural units derived from the non-aqueous monomer and the structural units derived from the polyfunctional ethylenically unsaturated monomer is preferably 60 to 100% by mass, more preferably 80 to 100% by mass, and even more preferably 90 to 100% by mass. The upper limit of the total content may be 99.9% by mass or 99% by mass.

[0132] The second polymer may contain one or more structural units derived from the above-mentioned monomer (BAB1) (particularly, the structural unit represented by formula (3), the same applies hereinafter), but preferably does not contain any. The content of the structural units derived from the monomer (BAB1) in the second polymer is preferably less than the content (content ratio) of the structural units derived from the monomer (BAB1) in the crosslinked polymer, specifically, preferably 10% by mass or less, more preferably 5% by mass or less.

[0133] The second polymer may contain one or more structural units derived from a monomer having one polymerizable group such as a carbon-carbon double bond-containing group per molecule (hereinafter referred to as "second other monomer") other than the structural units derived from the non-aqueous monomer, the structural units derived from the polyfunctional ethylenically unsaturated monomer, and the structural units derived from the monomer (BAB1).

[0134] Examples of the second other monomer include monomers having a carboxy group, a thiol group, a silanol group, an amino group, etc., such as a carboxy group-containing monomer, a silane group-containing monomer, a hydroxy group-containing monomer, a nitrogen atom-containing monomer, a light-stabilizing monomer, an ultraviolet absorbing monomer, etc. Examples of these carboxy group-containing monomers, silane group-containing monomers, hydroxy group-containing monomers, nitrogen atom-containing monomers, light-stabilizing monomers, and ultraviolet absorbing monomers are the same as the monomers described above for the crosslinked polymer, and preferred aspects of each monomer are also the same.

[0135] The content of the structural unit derived from the second other monomer in the second polymer is preferably 30% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less or 3% by mass or less.

[0136] The volume average particle diameter of the polymer particles is, for example, 10 nm to 10 μm, preferably 10 nm to 5 μm, more preferably 20 nm to 1 μm, and even more preferably 30 nm to 500 nm. From the viewpoint of further enhancing hydrophilicity after adhesion of oily soils, it is preferably 10 nm to 500 nm, more preferably 15 nm to 300 nm, and even more preferably 20 nm to 100 nm. The volume average particle diameter can be measured, for example, by dynamic light scattering.

[0137] The hydrophilic treatment composition of the present invention essentially contains the polymer particles, i.e., hydrophilic particles (B). The content of the hydrophilic particles (B) in the hydrophilic treatment composition of the present invention is, for example, 0.01% by mass or more, preferably 10% by mass or more, more preferably 30% by mass or more, even more preferably 50% by mass or more, still more preferably 90% by mass or more, particularly preferably 98% by mass or more, and may also be 100% by mass or 99.8% by mass or less.

[0138] The hydrophilic treatment composition preferably further contains a crosslinking agent. By including a crosslinking agent, the strength of the hydrophilic layer containing the hydrophilic treatment composition of the present invention can be increased. Furthermore, by including a crosslinking agent, the durability of the hydrophilic layer is improved, resulting in improved hydrophilicity retention and improved water slippage of the hydrophilic layer after heat cycling, as shown in the examples described below. The crosslinking agent may be used alone or in combination of two or more. The crosslinking agent is preferably a compound having two or more groups per molecule that can react with the polar functional group of the hydrophilic treatment composition. Examples of groups that can react with polar functional groups include epoxy groups, oxazoline groups, carbodiimide groups, isocyanate groups, etc., and may be selected appropriately depending on the hydrophilic treatment composition to be used.

[0139] Examples of crosslinking agents include at least one selected from melamine resins, urea resins, polyaldehyde compounds, phenolic resins, polyepoxy compounds, blocked polyisocyanate compounds, metal compounds (metal salts), metal complexes, metal oxides, metal hydroxides, etc.), oxazoline compounds, carbodiimide compounds, hydroxyalkylamide compounds, hydrazide compounds, semicarbazide compounds, and silicate compounds. In particular, it is preferable to use a crosslinking agent having two or more oxazoline groups in one molecule, and by combining it with the hydrophilic treatment composition of the present invention, the above-mentioned durability improvement effect tends to be further enhanced.

[0140] As a crosslinking agent having two or more oxazoline groups per molecule, a water-soluble oxazoline compound is preferred from the viewpoint of excellent crosslinking performance, and an oxazoline group-containing polymer is also preferred. The oxazoline group-containing polymer can be produced by a conventionally known production method. For example, a method of polymerizing a monomer component containing one or more addition-polymerizable oxazolines, or an addition-polymerizable oxazoline and a monomer copolymerizable with the addition-polymerizable oxazoline, can be mentioned.

[0141] Examples of the addition-polymerizable oxazoline include compounds having a polymerizable unsaturated group and an oxazoline group in the molecule, such as 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline. Preferred monomers copolymerizable with the addition-polymerizable oxazoline are monomers that do not have a functional group reactive with the oxazoline group and are copolymerizable with the addition-polymerizable oxazoline. For example, (meth)acrylic monomers such as alkyl (meth)acrylates; styrene-based monomers such as styrene, α-methylstyrene, and chloromethylstyrene; vinyl-based monomers such as vinyl acetate, vinyl chloride, and vinyl benzoate; acrylonitrile; (meth)acrylamide-based monomers such as acrylamide; and olefin-based monomers such as ethylene and propylene.

[0142] Among the oxazoline group-containing polymers, water-soluble oxazoline group-containing polymers are preferred, and can be produced by the same method as the above-mentioned method for producing the oxazoline group-containing polymer. Examples of the water-soluble oxazoline group-containing polymer include polymers having a main chain of a (meth)acrylic resin or the like and containing oxazoline groups in side chains.

[0143] Commercially available oxazoline group-containing polymers can also be used, including, for example, water-soluble polymers such as EPOCROS WS-500 and EPOCROS WS-700, and emulsion polymers such as EPOCROS K-2010E, EPOCROS K-2020E, and EPOCROS K-2035E, all of which are manufactured by Nippon Shokubai Co., Ltd.

[0144] The content of the crosslinking agent is not particularly limited, but is preferably 0.1 to 50 parts by mass, more preferably 1 to 40 parts by mass, and even more preferably 5 to 30 parts by mass, relative to 100 parts by mass of the copolymer (A).

[0145] The hydrophilic treatment composition may further contain a solvent. By containing a solvent, the coating properties of the hydrophilic treatment composition become good. As the solvent, an aqueous solvent is preferable from the viewpoint of reducing the environmental load. The aqueous solvent may be water alone or a mixed solvent of water and a water-miscible organic solvent. Typically, the aqueous solvent refers to a solvent having a water content of more than 50% by volume. As the water, ion-exchanged water (deionized water), distilled water, pure water, etc. can be used. As the water-miscible organic solvent, an organic solvent that can be uniformly mixed with water (for example, C １－４ Alkyl alcohols and other lower alcohols can be used.

[0146] The content of the solvent in the hydrophilic treatment composition may be 0% by mass, is preferably 0.1% by mass or more, more preferably 40% by mass or more, even more preferably 60% by mass or more, and particularly preferably 80% by mass or more, and is preferably 99.9% by mass or less, and more preferably 99% by mass or less.

[0147] [Method for producing copolymer (A)] The production of copolymer (A) of the present invention is not particularly limited, but it can be produced by polymerizing monomer components, specific examples and preferred examples of which are as described above. The proportion of each structural unit in the copolymer obtained by the polymerization reaction can be calculated based on the proportion of each monomer used as a reaction raw material and the remaining amount of monomer measured by high performance liquid chromatography.

[0148] In producing the copolymer, a chain transfer agent can be used to adjust the molecular weight of the resulting polymer. Examples of the chain transfer agent include thiol-based chain transfer agents such as mercaptoethanol, thioglycerol, thioglycolic acid, 3-mercaptopropionic acid, thiomalic acid, and 2-mercaptoethanesulfonic acid; secondary alcohols such as isopropyl alcohol; and hydrophilic chain transfer agents such as lower oxides and salts of phosphorous acid, hypophosphorous acid, and salts thereof (sodium hypophosphite, potassium hypophosphite, etc.), sulfurous acid, hydrogen sulfite, dithionous acid, metabisulfite, and salts thereof (sodium sulfite, sodium hydrogen sulfite, sodium dithionite, sodium metabisulfite, etc.).

[0149] A hydrophobic chain transfer agent can also be used as the chain transfer agent. Suitable examples of the hydrophobic chain transfer agent include thiol-based chain transfer agents having a hydrocarbon group with three or more carbon atoms, such as butanethiol, octanethiol, decanethiol, dodecanethiol, hexadecanethiol, octadecanethiol, cyclohexyl mercaptan, thiophenol, octyl thioglycolate, and octyl 3-mercaptopropionate. Furthermore, in order to adjust the molecular weight of the copolymer, it is also effective to use a monomer with high chain transfer properties, such as (meth)allylsulfonic acids (salts).

[0150] The amount of the chain transfer agent used may be appropriately determined, but is preferably 0.1 mol or more, more preferably 0.25 mol or more, and even more preferably 0.5 mol or more, relative to 100 mol of the total amount of the monomer components, and is preferably 20 mol or less, more preferably 15 mol or less, and even more preferably 10 mol or less.

[0151] The polymerization reaction can be carried out by a method such as solution polymerization or bulk polymerization, using a radical polymerization initiator as necessary. Solution polymerization can be carried out batchwise or continuously, or a combination thereof, and examples of the solvent used in this case include water; alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; aromatic or aliphatic hydrocarbons such as benzene, toluene, xylene, cyclohexane, and n-hexane; ester compounds such as ethyl acetate; ketone compounds such as acetone and methyl ethyl ketone; and cyclic ether compounds such as tetrahydrofuran and dioxane. Among these, polymerization by aqueous solution polymerization is preferred.

[0152] When the aqueous solution polymerization is carried out, a water-soluble polymerization initiator is used as the radical polymerization initiator, for example, a persulfate such as ammonium persulfate, sodium persulfate, or potassium persulfate; hydrogen peroxide; azoamidine compounds such as 2,2'-azobis-2-methylpropionamidine hydrochloride; cyclic azoamidine compounds such as 2,2'-azobis-2-(2-imidazolin-2-yl)propane hydrochloride; or azonitrile compounds such as 2-carbamoylazoisobutyronitrile. In this case, an accelerator such as an alkali metal sulfite such as sodium hydrogensulfite, metabisulfite, sodium hypophosphite, Fe(II) salts such as Mohr's salt, sodium hydroxymethanesulfinate dihydrate, hydroxylamine hydrochloride, thiourea, L-ascorbic acid (salt), or erythorbic acid (salt) may also be used in combination. Among these, persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate, and combinations of hydrogen peroxide with an accelerator such as L-ascorbic acid (salt) are preferred. These radical polymerization initiators and accelerators may be used alone or in combination of two or more. Furthermore, when solution polymerization is performed using a lower alcohol, an aromatic or aliphatic hydrocarbon, an ester compound, or a ketone compound as the solvent, or when bulk polymerization is performed, peroxides such as benzoyl peroxide, lauroyl peroxide, and sodium peroxide; hydroperoxides such as t-butyl hydroperoxide and cumene hydroperoxide; and azo compounds such as azobisisobutyronitrile are used as radical polymerization initiators. In this case, accelerators such as amine compounds can also be used in combination. Furthermore, when a water-lower alcohol mixed solvent is used, the radical polymerization initiators or combinations of radical polymerization initiators and accelerators described above can be appropriately selected and used.

[0153] The amount of the radical polymerization initiator used is preferably 0.001 mol or more, more preferably 0.01 mol or more, even more preferably 0.1 mol or more, particularly preferably 0.2 mol or more, relative to 100 mol of the total amount of the monomer components, and is preferably 20 mol or less, even more preferably 10 mol or less, particularly preferably 7 mol or less, and most preferably 5 mol or less.

[0154] In the polymerization reaction, polymerization conditions such as polymerization temperature are appropriately determined depending on the polymerization method, solvent, polymerization initiator, and chain transfer agent used, but the polymerization temperature is preferably 0°C or higher and 150°C or lower, more preferably 30°C or higher, and even more preferably 50°C or higher, and more preferably 120°C or lower, and even more preferably 100°C or lower.

[0155] The method for adding each monomer component to the reaction vessel is not particularly limited, and examples include a method in which the entire amount is added to the reaction vessel all at once at the beginning; a method in which the entire amount is added to the reaction vessel in portions or continuously; a method in which a portion is added to the reaction vessel initially and the remainder is added to the reaction vessel in portions or continuously. Furthermore, the addition rate of each monomer to the reaction vessel may be changed continuously or stepwise during the reaction, thereby changing the weight ratio of each monomer added per unit time continuously or stepwise, thereby simultaneously synthesizing two or more copolymers with different monomer ratios during the polymerization reaction. The radical polymerization initiator may be charged to the reaction vessel from the beginning, or may be added dropwise to the reaction vessel, or a combination of these may be used depending on the purpose.

[0156] Each polymer obtained as described above can be used as it is for preparing a hydrophilic treatment composition, but if necessary, it may be further neutralized with an alkaline substance before use. Suitable alkaline substances include inorganic salts such as hydroxides and carbonates of monovalent or divalent metals; ammonia; and organic amines. Furthermore, after the reaction is completed, the concentration can be adjusted if necessary.

[0157] [Method for producing hydrophilic particles (B)] The method for producing the polymer particles, which are hydrophilic particles (B), is not particularly limited, and a conventionally known method may be adopted, but it is preferable to produce the polymer particles by polymerizing the monomers constituting the polymer particles (hereinafter, these may be collectively referred to as "raw material monomer components") in an aqueous solvent and, if necessary, partially or completely hydrolyzing them. For example, when producing polymer particles containing the crosslinked polymer of aspect 4, the raw material monomer components, which are hydroxymethylacrylic acid-based monomers represented by the above formula, are used. １is an alkyl group having 1 to 4 carbon atoms (hereinafter referred to as hydroxymethyl acrylate ester), a polyfunctional ethylenically unsaturated monomer, and optionally a polyoxyalkylene group-containing ethylenically unsaturated monomer, other monomers, a non-aqueous monomer, and a second other monomer are polymerized in an aqueous solvent, followed by partial or complete hydrolysis as required. The use of hydroxymethyl acrylate ester is preferred from the viewpoint of reducing the environmental load, since the product can be made into a particulate form even when polymerized in an aqueous solvent that does not require an organic solvent.

[0158] Examples of polymerization methods include suspension polymerization, emulsion polymerization, and dispersion polymerization. Among them, emulsion polymerization is preferred, in which the raw material monomer components are dispersed in an aqueous solvent in the presence of an emulsifier and subjected to a (radical) polymerization reaction. The emulsion polymerization may be carried out in one stage or multiple stages. For example, in the first stage, a non-aqueous monomer, an optionally used polyfunctional ethylenically unsaturated monomer, a monomer (BAB1) (particularly, a hydroxymethylacrylic acid-based monomer represented by the above formula), and a second other monomer are polymerized in an aqueous solvent to synthesize seed particles that become the core (i.e., the second polymer), and then in the second stage, monomers that constitute the crosslinked polymer (preferably, a hydroxymethylacrylic acid ester, a polyfunctional ethylenically unsaturated monomer, and an optionally used polyoxyalkylene group-containing ethylenically unsaturated monomer and other monomers) are polymerized to synthesize a shell (i.e., the crosslinked polymer), thereby producing polymer particles having a core-shell structure.

[0159] The emulsifier may be one or more types, and may be a non-reactive surfactant having no radically polymerizable group in the molecule, or a reactive surfactant having a radically polymerizable group (e.g., an ethylenically unsaturated group) in the molecule.

[0160] Non-reactive surfactants include anionic and non-ionic surfactants. Examples of non-reactive anionic surfactants include fatty acid salts, alkyl (aryl) sulfonates, alkyl sulfate ester salts, and polyoxyethylene alkyl (phenyl) ether sulfates. Examples of non-reactive nonionic surfactants include polyoxyethylene alkyl (phenyl) ethers, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene fatty acid esters, and polyoxyethylene polyoxypropylene block polymers.

[0161] Reactive surfactants include anionic and nonionic surfactants. Examples of anionic reactive surfactants include, but are not limited to, ether sulfate reactive surfactants and phosphate ester reactive surfactants.

[0162] The amount of the emulsifier used is preferably 0.05 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, even more preferably 0.2 to 5 parts by mass, and particularly preferably 0.3 to 3 parts by mass, relative to 100 parts by mass of the total of the raw material monomer components.

[0163] The aqueous solvent may be water alone or a mixed solvent of water and a water-miscible organic solvent. An aqueous solvent typically refers to a solvent having a water content of more than 50% by volume. Examples of water that can be used include ion-exchanged water (deionized water), distilled water, and pure water. Examples of water-miscible organic solvents that can be used include organic solvents that are uniformly miscible with water (e.g., lower alcohols such as C1-4 alkyl alcohols). From the viewpoint of minimizing the amount of water-miscible organic solvent remaining in the polymer particles, aqueous solvents containing 80% by volume or more of water are preferred, more preferably 90% by volume or more of water, even more preferably 95% by volume or more of water, and particularly preferably an aqueous solvent consisting essentially of water (an aqueous solvent containing 99.5% by volume or more of water). Water alone is most preferred.

[0164] When polymerizing the raw material monomer components, for example, a polymerization initiator, irradiation with ultraviolet rays or radiation, application of heat, or the like is used. The use of a polymerization initiator is preferred, and a polymerization initiator combining an oxidizing agent and a reducing agent (redox polymerization initiator) is preferred from the viewpoint of efficiently reacting the raw material monomer components and sufficiently reducing the amount of residual monomer. Examples of the oxidizing agent include persulfates such as ammonium persulfate and potassium persulfate, and peroxide-based polymerization initiators such as hydrogen peroxide, benzoyl peroxide, parachlorobenzoyl peroxide, lauroyl peroxide, and ammonium peroxide. Examples of the reducing agent include soluble sulfites and ascorbic acid.

[0165] If necessary, an appropriate amount of additives such as a chain transfer agent, a pH buffer, a chelating agent, etc. may be added to the reaction system in the emulsion polymerization. The amount of the additive varies depending on the type of additive and cannot be determined in general, but is usually preferably 0.01 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the raw material monomer components.

[0166] The hydrolysis of the polymer particles can be carried out by adding, for example, an aqueous solution of an alkali metal hydroxide such as an aqueous solution of sodium hydroxide, an aqueous solution of an amine such as an aqueous solution of cyclohexylamine, or an aqueous solution containing a basic substance such as an aqueous solution of ammonia. Furthermore, partial or complete neutralization can be carried out by adding an acid to the solution after hydrolysis. By carrying out the hydrolysis and neutralization, the group corresponding to R in the -COOR group contained in the polymer particles (particularly, R in formula (3) １ The amount of acid or base used during polymerization, hydrolysis, and neutralization can be adjusted, and R (especially R １By adjusting the proportion of monomer units in which the aryl group is a hydrogen atom, the pH and hydrophilicity of the polymer can be adjusted, which tends to further enhance the sustained hydrophilicity and water slippage of tangible objects such as hydrophilic coatings. The hydrolysis rate of the polymer particles of the present disclosure is, for example, 20 to 100%, preferably 40 to 100%, and more preferably 50 to 100%, from the viewpoint of further enhancing hydrophilic properties and water slippage. The hydrolysis rate may be 95% or less, or even 90% or less. The hydrolysis rate can be calculated from the amount (amount of substance) of the basic substance added per 100 mol% of the structural units derived from the hydrolyzable monomer contained in the crosslinked polymer. Examples of hydrolyzable monomers include acrylic monomers such as alkyl acrylate esters and hydroxymethylacrylic acid-based monomers represented by the above formula. When back-calculating the hydrolysis rate from the polymer, the hydrolysis rate can be calculated assuming that all of the carboxylic acid groups in the acrylic monomers and hydrolyzable monomers such as the hydroxymethylacrylic acid-based monomers represented by the above formula are present as esters.

[0167] [Method for producing hydrophilic treatment composition] The method for producing the hydrophilic treatment composition of the present invention is not particularly limited, but may include, for example, a step of mixing the copolymer (A), the hydrophilic particles (B), and optionally a hydrophilic resin, a crosslinking agent, a solvent, and other additives (also referred to as mixing step (A)). In the mixing step (A), for example, mixing may be performed in the presence of a solvent (preferably an aqueous solvent) or in the absence of a solvent.

[0168] The hydrophilic treatment composition of the present invention may contain other additives as long as they do not impair the effects of the present invention. Examples of such additives include those commonly used in the art, such as water-soluble low-molecular-weight compounds having hydroxyl groups, such as L-ascorbic acid, gallic acid, and tannic acid, and polymeric compounds having hydroxyl groups, such as polyvinyl alcohol. If necessary, the composition may contain a solvent, such as the aqueous solvents listed above. In addition to the hydrophilic particles (B), silica particles may also be used. Examples of silica particles include silica sol and finely divided silica.

[0169] A preferred embodiment of the hydrophilic treatment composition of the present invention will be described. [Hydrophilic layer formed using the hydrophilic treatment composition] The hydrophilic layer, such as a hydrophilic coating film, formed from the hydrophilic treatment composition of the present invention contains the above-mentioned hydrophilic treatment composition, and therefore has not only good hydrophilicity but also sustained hydrophilicity and / or good water-slip properties. Therefore, the hydrophilic treatment composition is suitably applied to tangible objects (i.e., objects to be hydrophilized) that require not only hydrophilicity but also sustained hydrophilicity and / or water-slip properties, and is particularly suitably used for hydrophilic coating films applied to fin materials (heat exchanger fins) of heat exchangers.

[0170] As a specific example of a preferred embodiment of the hydrophilic treatment composition of the present invention, a heat exchanger fin having a hydrophilic layer (e.g., a hydrophilic coating film) containing the copolymer (A) and the hydrophilic particles (B) formed on its surface is used. The thickness of the hydrophilic layer formed on the fin is preferably, for example, 0.1 to 80 μm.

[0171] In addition, when the hydrophilic layer exhibits a hydrophilicity sustaining effect, it is preferable that the following (a) and (b) are satisfied, for example: (a) the initial contact angle (θ0) measured by the method described in <Evaluation of initial hydrophilicity> in the Examples is less than 40°; (b) the contact angle (θ5) after wet / dry cycling measured by the method described in <Evaluation of hydrophilicity sustaining effect after wet / dry cycling> in the Examples is less than 40°.

[0172] The initial contact angle of the hydrophilized layer is preferably less than 35°, more preferably 30° or less, even more preferably 20° or less, and particularly preferably 15° or less or less than 15°. The lower limit of the initial contact angle is not particularly limited, but is, for example, 5° or more.

[0173] The contact angle of the hydrophilized layer after wet / dry cycling is preferably less than 35°, more preferably 30° or less, even more preferably 26° or less, still more preferably 20° or less, and particularly preferably 15° or less or less than 15°. The lower limit of the contact angle is not particularly limited, but is, for example, 8° or more.

[0174] In a more preferred embodiment, the relationship between the initial contact angle (θ0) and the contact angle (θ5) in the hydrophilized layer satisfies the following (c) or (d): (c) contact angle (θ5)≦initial contact angle (θ0); (d) contact angle (θ5)>initial contact angle (θ0), and the absolute value of the difference between the contact angle (θ5) and the initial contact angle (θ0) is 20° or less. When the relationship between the initial contact angle (θ0) and the contact angle (θ5) in the hydrophilized layer satisfies (c), any absolute value of the difference between the contact angle (θ5) and the initial contact angle (θ0) is preferred, but 1° or more is more preferred, and 3° or more is even more preferred. The upper limit of the absolute value of the difference is not particularly limited, but is, for example, 15° or less. When the relationship between the initial contact angle (θ0) and the contact angle (θ5) in the hydrophilic layer satisfies the condition (d), the smaller the absolute value of the difference between the contact angle (θ5) and the initial contact angle (θ0) is, the better. Specifically, the absolute value is 20° or less, preferably 15° or less, and more preferably 10° or less.

[0175] When the hydrophilized layer exhibits both hydrophilicity and water-slippage properties, it is preferable that the hydrophilized layer satisfy the above-mentioned initial contact angle (θ0) and the following condition (i): (i) the sliding angle (θs) measured by the method described in <Evaluation of water-slippage properties> in the examples is less than 30°

[0176] The sliding angle (θs) of the hydrophilized layer is preferably 20° or less, more preferably 15° or less or less than 15°, even more preferably 12° or less, and particularly preferably 10° or less. Conventional sliding angle measurements did not take into account the influence of wetting and spreading of a droplet due to the hydrophilicity of the measurement substrate surface. Therefore, for a hydrophilic tangible object (i.e., a hydrophilized layer), a good sliding angle measured by a conventional measurement method did not necessarily mean good water-slip properties. That is, in conventional methods, the sliding angle was determined by the inclination angle of the hydrophilized layer when a water droplet was placed on the hydrophilized layer and the water droplet moved a certain distance in the sliding direction. However, when a water droplet was placed on the hydrophilized layer, the wetting and spreading movement of the water droplet was observed. When the sliding angle was measured under this condition, both sliding and wetting movements were observed simultaneously, which sometimes made it difficult to accurately evaluate the water-slip properties. It was also possible to measure the sliding angle after the wetting and spreading movement reached an equilibrium point, but this is not preferable because the water in the droplet may evaporate before reaching the equilibrium point. Therefore, in order for a hydrophilized layer having hydrophilic properties to have good water-sliding properties, it is required that the sliding angle be small in a measurement system that takes into account the influence of the wetting and spreading of a water droplet.On the other hand, in the evaluation of water-sliding properties of the present invention, as will be described later, an evaluation method is adopted that aims to extract the end point movement due to sliding from the end point movement of a water droplet in the sliding direction, excluding the influence of the end point movement due to wetting and spreading.In this evaluation method, the hydrophilized layer of the present invention that can reduce the sliding angle can be said to have good water-sliding properties while being hydrophilic.

[0177] The shape of the hydrophilic layer is not particularly limited, and examples thereof include a coating film shape, a surface shape (film, sheet, plate), granular, powdery, lumpy, particle aggregate shape, spherical, oval sphere shape, lens shape, columnar, rod shape, conical shape, cylinder shape, needle shape, fiber shape, fiber aggregate shape (e.g., woven fabric, nonwoven fabric, etc.), hollow fiber shape, porous shape, etc. Among these, a coating film shape is preferred.

[0178] The thickness of the hydrophilic layer is not particularly limited, but is, for example, 0.1 to 80 μm, preferably 0.1 to 50 μm, more preferably 0.1 to 10 μm, and even more preferably 0.3 to 5 μm.

[0179] The method for producing the hydrophilic layer is not particularly limited, and any conventionally known method may be appropriately adopted. For example, the hydrophilic layer can be obtained by molding or forming the hydrophilic treatment composition described above.

[0180] Furthermore, according to the present invention, by providing a hydrophilic layer containing the hydrophilic treatment composition of the present invention on the surface of a substrate, which is the object of hydrophilic treatment, it is possible to impart sustained hydrophilicity and / or water slippage to the surface of the substrate. That is, according to the present invention, by providing a hydrophilic layer containing the hydrophilic treatment composition on the surface of a substrate, it is possible to provide sustained hydrophilicity and / or water slippage to the surface of the substrate. In both cases of forming a hydrophilic layer containing a hydrophilic treatment composition and forming a hydrophilic layer containing a hydrophilic treatment composition on the surface of a substrate, the forming or forming method is not particularly limited, and may be appropriately selected depending on the type of composition used and the shape of the target substrate. Examples of forming or forming methods include a method of forming a film by applying the hydrophilic treatment composition to a substrate by coating, spraying, printing, impregnation, etc.; a method of forming a molded body by injection molding, extrusion molding, vacuum molding, compression molding, blow molding, etc. of the hydrophilic treatment composition; and a method of laminating the hydrophilic treatment composition on the surface of a substrate. Among these, it is preferable to form a hydrophilic layer containing the hydrophilic treatment composition on the surface of the substrate by applying the hydrophilic treatment composition to the substrate.

[0181] The hydrophilic treatment object, such as a substrate, may be made of a resin, such as polyester, polyethylene, polypropylene, triacetyl cellulose, polystyrene, polycarbonate, polyethersulfone, cellophane, polyamide, polyvinyl alcohol, polyacetal, polyphenylene ether, polyphenylene sulfide, polyimide, polyamideimide, polyetherimide, polyetheretherketone, fluororesin such as polytetrafluoroethylene, ABS resin, Noryl resin, acrylic resin, epoxy resin, cellophane, etc. In addition to the resins, inorganic materials such as glass, slate, and mortar; metals such as stainless steel plate, iron, copper, aluminum, magnesium, and zinc, and their alloys; etc., are also included, but the present invention is not limited to these examples. The hydrophilic treatment object may be made of only a single layer, or may have a laminate structure in which multiple layers are stacked. In particular, the hydrophilic treatment object is preferably a fin material for a heat exchanger, and more preferably an aluminum fin material.

[0182] When a hydrophilic treatment composition is applied to an object to be hydrophilized by coating, spraying, printing, impregnation, or other methods to form a coating film (hereinafter referred to as a hydrophilic coating film), if a crosslinking agent is applied to the hydrophilic coating film, it may be mixed in advance with the hydrophilic treatment composition or may be added after film formation. When a hydrophilic layer containing the hydrophilic treatment composition of the present invention is applied to a fin material (particularly an aluminum fin material) of a heat exchanger, it may be formed directly on the surface of the fin material (particularly an aluminum plate constituting the aluminum fin material) (i.e., the fin material (particularly an aluminum plate constituting the aluminum fin material) and the hydrophilic layer may be directly laminated), or it may be formed via an underlayer such as a chemical conversion layer and / or a resin coating layer provided on the surface of the fin material (particularly an aluminum plate constituting the aluminum fin material) for the purpose of preventing corrosion of the fin material (particularly the aluminum constituting the aluminum fin material) (i.e., the fin material (particularly the aluminum plate constituting the aluminum fin material) and the hydrophilic layer may be laminated via an underlayer).

[0183] The chemical conversion treatment layer can be a conventionally known one, for example, a layer made of an inorganic oxide or an inorganic-organic composite compound. The inorganic material constituting the inorganic oxide or inorganic-organic composite compound preferably has a main component of chromium, zirconium, or titanium. A layer made of an inorganic oxide can be formed, for example, by subjecting a fin material (particularly an aluminum plate constituting an aluminum fin material) to a chromate phosphate treatment, a zirconium phosphate treatment, a zirconium oxide treatment, a chromate chromate treatment, a zinc phosphate treatment, a titanic acid phosphate treatment, or the like. A layer made of an inorganic-organic composite compound can be formed, for example, by subjecting a fin material (particularly an aluminum plate constituting an aluminum fin material) to a coating-type chromate treatment, a coating-type zirconium treatment, or the like. Specific examples of such inorganic-organic composite compounds include, for example, an acrylic-zirconium composite.

[0184] The resin coating layer can be formed, for example, by applying a resin-containing resin paint to the fin material (particularly the aluminum plate or chemical conversion coating layer that constitutes the aluminum fin material) and solidifying it by drying or the like. The resin can be a conventionally known resin, such as polyester-based, polyolefin-based, epoxy-based, urethane-based, or (meth)acrylic resin, and a mixture of one or more of these can be used. Among these, (meth)acrylic resins are preferred, and a polymer having a (meth)acrylic resin or the like as a main chain and containing an oxazoline group in the side chain can also be used.

[0185] In addition to the above, the resin coating layer may contain other optional components within the range that does not impair the effects of the present invention. These optional components include various paint additives for improving coatability, workability, and film physical properties, such as aqueous solvents, crosslinking agents, surfactants, film-forming aids, surface conditioners, wetting and dispersing agents, anti-settling agents, antioxidants, antifoaming agents, rust inhibitors, antibacterial agents, and anti-fungal agents. These paint additives may be used alone or in combination of two or more.

[0186] The method for producing the hydrophilic layer is not particularly limited, but may include a drying step or a curing step after the film-forming step such as coating, spraying, printing, or impregnation.

[0187] This application claims the benefit of priority based on Japanese Patent Application No. 2024-070008, filed on April 23, 2024. The entire contents of the specification of Japanese Patent Application No. 2024-070008, filed on April 23, 2024, are incorporated herein by reference.

[0188] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples, and can of course be practiced with appropriate modifications within the scope of the above and below-described aims, all of which are included within the technical scope of the present invention. In the following, unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass."

[0189] <Gel Permeation Chromatography (GPC)> The weight-average molecular weight of the copolymers produced in the following Production Examples was measured by the following method. Apparatus: Alliance (e2695) (manufactured by Waters) Analysis software: Empower2 Professional + GPC option (manufactured by Waters) Columns used: TSKguard columns SWXL (inner diameter: 6.0 mm × 40 mm) + TSKgel G4000SWXL (inner diameter: 7.8 mm × 300 mm) + G3000SWXL (inner diameter: 7.8 mm × 300 mm) + G2000SWXL (inner diameter: 7.8 mm × 300 mm) (all manufactured by Tosoh Corporation) Detector: differential refractometer (RI) detector (manufactured by Waters, Waters 2414) Eluent: 115.6 g of sodium acetate trihydrate dissolved in a mixed solvent of 10,999 g of ion-exchanged water and 6,001 g of acetonitrile, and further adjusted to pH 6.0 with acetic acid. Flow rate: 1 mL / min. Column temperature: 40°C. Measurement time: 45 min. Sample injection amount: 100 μL (eluent solution with a sample concentration of 0.5% by mass). GPC standard sample: polyethylene glycol manufactured by Tosoh Corporation, Mp = 255,000, 200,000, 107,000, 72,750, 44,900, 31,400, 21,300, 11,840, 6,450, 4,020, 1,470. Calibration curve: Created using a cubic equation using the Mp values ​​of the above polyethylene glycol.

[0190] <High-Performance Liquid Chromatography (LC)> The remaining amounts of various monomers used as reaction raw materials in the following production examples were measured under the following conditions and used to calculate the composition of the copolymer. Apparatus: Alliance 2695 (Waters) Analysis software: Empower Professional (Waters) Column: Atlantis dC18 5 μm (inner diameter 4.6 mm × length 250 mm) × 2 (Waters) Detector: differential refractometer (RI) detector (Waters 2414), multi-wavelength visible ultraviolet (PDA) detector (Waters 2996) Solvent: solution of 100 mM aqueous sodium acetate solution and acetonitrile mixed in a 6:4 ratio Flow rate: 1 mL / min Column temperature: 40°C Measurement time: 30 min Sample solution injection amount: 100 μL (sample concentration: 1% by mass)

[0191] <Evaluation of Initial Hydrophilicity> Using an automatic contact angle meter ("CA-X" manufactured by Kyowa Interface Science Co., Ltd.), a 2 μL droplet of pure water was prepared at 25° C. and applied to the surface of the coating film (hydrophilized layer) of the film-formed sample prepared as described below, and the contact angle was calculated by the θ / 2 method. The contact angle value 30 seconds after application was taken as the measured value, and five measurements were performed, and the average value of three points excluding the maximum and minimum values ​​was taken as the initial contact angle of the coating film (hydrophilized layer). The initial hydrophilicity of the coating film (hydrophilized layer) was quantitatively evaluated according to the following criteria: ◎: Initial contact angle less than 15° ○: Initial contact angle 15° or more but less than 40° ×: Initial contact angle 40° or more

[0192] <Evaluation of Hydrophilicity Sustaining Effect After Wet / Dry Cycles> The coating film (hydrophilized layer) of the film-formed sample prepared as described below was immersed in pure water for 6 hours, and then, in an environment of 25°C and 50% humidity, the removed film-formed sample was placed on a Kimwipe so that the contact angle measurement surface (coated surface of the sample) was facing up, and another Kimwipe was covered from above and maintained in this state for 5 seconds. The sample was then removed, and excess water was removed by blowing air onto the contact angle measurement surface until no visible water droplets remained. The sample was then dried at 80°C in an air atmosphere using an air-blowing constant temperature incubator (Yamato Scientific Co., Ltd., "DNF400") for 2 hours to obtain a sample after wet / dry cycling. Using an automatic contact angle meter (Kyowa Interface Science Co., Ltd., "CA-X"), a 2 μL droplet of pure water was prepared at 25°C and applied to the coating surface of the sample after wet / dry cycling, and the contact angle was calculated using the θ / 2 method. The contact angle value 30 seconds after contact with the surface was taken as the measured value, and five measurements were taken. The average of the three measurements, excluding the maximum and minimum values, was taken as the contact angle after the wet / dry cycle. The hydrophilicity retention effect of the coating film after the wet / dry cycle was quantitatively evaluated according to the following criteria: ◎: Contact angle after the wet / dry cycle is less than 15° ○: Contact angle after the wet / dry cycle is 15° or more but less than 40° ×: Contact angle after the wet / dry cycle is 40° or more

[0193] <Evaluation of Water Slippage> To evaluate the sliding properties, the sliding angle of a water droplet relative to the coating surface of the film-formed sample was measured. The water slippage was evaluated using a sample after five wet / dry cycles. Specifically, using an automatic contact angle meter ("CA-X" manufactured by Kyowa Interface Science Co., Ltd.), a 10 μL droplet of pure water was prepared at 25°C and deposited on the horizontally placed coating surface after the heat cycle (5C) (the coating surface of the sample after the heat cycle). 0.1 seconds after deposition, the sample was gradually tilted at a rate of 2° / sec in 0.5° increments, and the angle at which the water droplet began to move was recorded as the measured value. Five measurements were taken, and the average of the three points, excluding the maximum and minimum values, was taken as the sliding angle θs. The water slippage of the coating was then quantitatively evaluated according to the following criteria. ◎: sliding angle θs less than 15° ○: sliding angle θs 15° or more and less than 30° ×: sliding angle θs 30° or more Note that, as shown in Figure 1, the movement of the water droplet was determined as follows: R0 was the end point of the water droplet (2a) on the opposite side to the sliding direction 0.1 seconds after it landed on the coating surface of the formed sample 1, and L0 was the end point on the sliding direction side; Rθ was the end point of the water droplet (2b) on the opposite side to the sliding direction at an inclination angle θ, and Lθ was the end point on the sliding direction side; the movement distance of the end point on the opposite side to the sliding direction of the water droplet dR = -|Rθ - R0|, and the movement distance of the end point on the sliding direction side of the water droplet dL = |Lθ - L0|. The water droplet was determined to have moved when dR + dL > 1.00 mm was first satisfied, and the inclination angle θ at that time was defined as the sliding angle θs. This definition is an evaluation method intended to extract the end point movement due to sliding by excluding the influence of the end point movement due to wetting and spreading from the end point movement of the water droplet in the sliding direction.

[0194] [Copolymer (A)] [Production Example 1] Ion-exchanged water was charged into a glass reaction vessel equipped with a thermometer, a stirrer, a dropping device, a nitrogen inlet tube, and a reflux condenser. The atmosphere inside the reaction vessel was then replaced with nitrogen under stirring. The temperature was raised to 60°C under a nitrogen atmosphere, and then an aqueous hydrogen peroxide solution was added. Next, an aqueous solution of methacrylic acid (AA), methoxypolyethylene glycol (average number of moles added: 10) monomethacrylate (PGM-10E), and 3-mercaptopropionic acid dissolved in ion-exchanged water was added dropwise over 4 hours, and an aqueous solution of L-ascorbic acid dissolved in ion-exchanged water was added dropwise over 4.5 hours, each at a constant rate. The temperature during this period was kept constant at 60°C, and after completion of the dropwise addition, the temperature was maintained at 60°C for 1 hour to terminate the polymerization reaction. Thereafter, the pH of the reaction solution was neutralized to pH = 6 using an aqueous sodium hydroxide solution at a temperature below the polymerization reaction temperature, yielding an aqueous solution containing copolymer (1).

[0195] [Production Examples 2 to 6] Copolymers (2) to (6) were produced in the same manner as in Production Example 1, except that the structural unit (A2) was changed in some of the production examples and the proportions of the respective structural units were changed as shown in Table 1.

[0196] [Production Example 7] (Hydrophilic Particles (1)) Into a stainless steel first reaction kettle equipped with a stirrer, a thermometer, and a cooler, 1,128 parts by mass of deionized water and 1.05 parts by mass of ADEKA REASOAP SR-20 (active ingredient 100% by mass, manufactured by ADEKA Corporation) diluted with ion-exchanged water to 10% by mass of the active ingredient (hereinafter referred to as "SR-20 (active ingredient 10% by mass)") were added, and the internal temperature was raised to 75°C and maintained at that temperature. Meanwhile, in a second reaction kettle different from the first reaction kettle, 70 parts by mass of methyl methacrylate (MMA) and 30 parts by mass of divinylbenzene (DVB810, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) were mixed to prepare 100 parts by mass of Monomer Composition A. Furthermore, in a third reactor different from the first and second reactors, 80 parts by mass of methyl 2-hydroxymethylacrylate (RHMA), 10 parts by mass of divinylbenzene (DVB810 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), and 10 parts by mass of methoxypolyethylene glycol monomethacrylate (BLEMMER PME400 manufactured by NOF Corporation) were mixed to prepare 100 parts by mass of monomer composition B. Next, the atmosphere inside the first reactor was purged with nitrogen gas, and then 100 parts by mass of the monomer composition A, 20 parts by mass of hydrogen peroxide solution (concentration 3.35% by mass), and 20 parts by mass of an aqueous L-ascorbic acid solution (concentration 5.0% by mass) were added to the first reactor, the internal temperature was maintained at 75 ° C., and an initial polymerization reaction was carried out over 2 hours. Subsequently, 100 parts by mass of the monomer composition B, 100 parts by mass of hydrogen peroxide solution (concentration 0.83% by mass), 100 parts by mass of an L-ascorbic acid aqueous solution (concentration 1.25% by mass), and 100 parts by mass of a mixed composition of 7.04 parts by mass of SR-20 (active ingredient 10% by mass), 0.36 parts by mass of an aqueous ammonia solution (concentration 28% by mass), and 92.6 parts by mass of ion-exchanged water were each added dropwise uniformly to the first reaction vessel from different inlets over a period of 3 hours. After completion of the addition, the internal temperature of the first reaction vessel was maintained at 75°C, and the mixture was aged at the same temperature for 2 hours. The reaction solution was then cooled to obtain an aqueous dispersion of polymer particles (a1). 10 parts by mass of the obtained aqueous dispersion of polymer particles (a1) and 1.2 parts by mass of an aqueous sodium hydroxide solution (concentration 20%) as a basic aqueous solution were added to the first reaction vessel and stirred overnight at 25°C to obtain an aqueous dispersion of hydrolyzed hydrophilic particles (1) as shown in Table 2. The volume average particle diameter of the obtained hydrophilic particles (1) was 302 nm.

[0197] [Hydrophiliic Treatment Composition] Hydrophilic Treatment Composition 1 Hydrophilic treatment composition 1 was produced using the copolymer (1) produced in Production Example 1. The copolymer (1), hydrophilic particles (1), and an aqueous crosslinking agent ("Epocross WS-700" manufactured by Nippon Shokubai Co., Ltd.; solid content 25% by mass) were blended in a solid content ratio (mass basis) of 100:100:18, and the mixture was diluted with pure water to a final solid content of 5.5% by mass, thereby obtaining hydrophilic treatment composition 1.

[0198] Hydrophilic Treatment Compositions 2 to 6 Hydrophilic treatment compositions 1 to 6 were produced in the same manner as in Example 1, except that copolymer (1) was changed as shown in Table 3.

[0199] Hydrophilic Treatment Compositions 7 to 12 Hydrophilic treatment compositions 7 to 12 were produced in the same manner as in Examples 1 to 6, except that the hydrophilic particles (1) were not used.

[0200] [Film-formed sample] Film-formed sample 1 Film-formed sample 1 was prepared using hydrophilic treatment composition 1. Specifically, the hydrophilic treatment composition (1) was applied to the undercoat layer-coated surface of an aluminum plate using a bar coater so that the film thickness after coating would be 1.0 μm, and the applied film was dried at 200° C. for 60 seconds in an automatic discharge dryer ("AT-101 (standard type)" manufactured by Tojo Netsugaku Co., Ltd.), to obtain film-formed sample 1 having a laminated coating film.

[0201] Film-formed Samples 2 to 12 Film-formed Samples 2 to 12 were prepared in the same manner as Film-formed Sample 1, except that the hydrophilic treatment composition was changed.

[0202] In the table, MAA: methacrylic acid PGM-10E: methoxypolyethylene glycol (average number of moles added: 10 moles) monomethacrylate PGM-25E: methoxypolyethylene glycol (average number of moles added: 25 moles) monomethacrylate PGM-40E: methoxypolyethylene glycol (average number of moles added: 40 moles) monomethacrylate The amount of basic aqueous solution added represents the number of moles of the added base when the number of moles of RHMA in the polymer particles (hydrophilic particles) is taken as 100 mol %, i.e., corresponds to the ionization rate and hydrolysis rate.

[0203]

[0204] In the table, RHMA: methyl 2-hydroxymethylacrylate, PME400: BLEMMER PME400 (methoxypolyethylene glycol monomethacrylate) manufactured by NOF Corporation, DVB810: DVB819 (divinylbenzene) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., MMA: methyl methacrylate

[0205]

[0206]

[0207] The results in Table 4 show that the use of the hydrophilic treatment composition of the present invention can impart good hydrophilicity and good water sliding properties to a coating film, and can improve the durability of the hydrophilicity of the resulting coating film after wet / dry cycles.

[0208] 1. Film-formed sample 2a. Water droplet 0.1 seconds after landing 2b. Water droplet at tilt angle θ R0. End point on the opposite side of the sliding direction of the water droplet 0.1 seconds after landing L0. End point on the sliding direction side of the water droplet 0.1 seconds after landing Rθ. End point on the opposite side of the sliding direction of the water droplet at tilt angle θ Lθ. End point on the sliding direction side of the water droplet at tilt angle θ

Claims

1. A hydrophilic treatment composition comprising: a copolymer (A) having at least one structural unit (A1) selected from the structural unit (A11) derived from a polymerizable monomer having a carboxyl group and the structural unit (A12) derived from a polymerizable monomer having a hydroxyl group; and a structural unit (A2) derived from a monomer in which a polyoxyalkylene group and a hydrocarbon group having a polymerizable double bond are linked via an ester bond; and hydrophilic particles (B) containing a crosslinked polymer having -COOR groups (R represents a hydrocarbon group, a hydrogen atom, an alkali metal atom, or ammonium) and a hydroxyl group.

2. The hydrophilic treatment composition according to claim 1, wherein the hydrocarbon group contained in the structural unit (A2) is an aliphatic hydrocarbon group.

3. The hydrophilic treatment composition according to claim 1, wherein the structural unit (A2) is derived from a monomer represented by the following formula (1): In the formula, R １ represents a hydrogen atom or a methyl group. ２ represents an alkylene group having 2 to 4 carbon atoms. ３ represents a hydrogen atom or an alkyl group having 1 to 30 carbon atoms, and n represents the average number of moles of oxyalkylene groups added, which is 2 to 500.

4. The hydrophilic treatment composition according to claim 1, further comprising a crosslinking agent.

5. The hydrophilic treatment composition according to claim 4, wherein the crosslinking agent has two or more oxazoline groups in one molecule.

6. The hydrophilic treatment composition according to claim 1, wherein the crosslinked polymer comprises a structural unit derived from a monomer (BAB1) having one or more -COOR groups, one or more hydroxyl groups, and one polymerizable group in one molecule, and a structural unit derived from a monomer (BC) having two or more polymerizable groups in one molecule.

7. The hydrophilic treatment composition according to claim 6, wherein the structural unit derived from the monomer (BAB1) is a structural unit represented by the following formula (2), and the structural unit derived from the monomer (BC) is a structural unit derived from a polyfunctional ethylenically unsaturated monomer: In formula (2), R １ represents an alkyl group having 1 to 4 carbon atoms, a hydrogen atom, an alkali metal atom, or ammonium.

8. The crosslinked polymer is a structural unit represented by the formula (2), R １ The hydrophilic treatment composition according to claim 7, wherein is an alkali metal atom or ammonium.

9. The hydrophilic treatment composition according to claim 1, wherein the hydrophilic particles (B) are single-layer particles or particles with a core-shell structure containing the crosslinked polymer in the shell layer.

10. The hydrophilic treatment composition according to claim 1, wherein the volume average particle size of the hydrophilic particles (B) is 10 nm to 10 μm.

11. The hydrophilic treatment composition according to claim 1, wherein the structural unit (A11) derived from a polymerizable monomer having a carboxyl group is a structural unit derived from an unsaturated monocarboxylic acid or a salt thereof.

12. The hydrophilic treatment composition according to claim 11, wherein the unsaturated monocarboxylic acid or its salt is acrylic acid, methacrylic acid, or a salt thereof.

13. The hydrophilization treatment composition according to claim 1, wherein the structural unit (A12) derived from a polymerizable monomer having a hydroxyl group is a structural unit derived from a (meth)acrylic acid hydroxyalkyl ester.

14. The hydrophilization treatment composition according to claim 1, wherein the structural unit (A2) is a structural unit derived from polyethylene glycol mono(meth)acrylate, polyethylene / polypropylene glycol mono(meth)acrylate, methoxypolyethylene glycol mono(meth)acrylate, methoxypolyethylene / polypropylene glycol mono(meth)acrylate, methoxypolyethylene glycol monomethacrylate, or methoxypolyethylene glycol monoacrylate.

15. The hydrophilic treatment composition according to claim 1, wherein the content of the structural unit (A2) is 30 to 99 parts by mass per 100 parts by mass of the total of the structural unit (A1) and the structural unit (A2).

16. The hydrophilic treatment composition according to claim 1, wherein the total content of the structural unit (A1) and the structural unit (A2) is 70 to 100 parts by mass per 100 parts by mass of the copolymer (A).

17. The hydrophilic treatment composition according to claim 1, wherein the object to be hydrophilically treated is a fin of a heat exchanger.

18. A heat exchanger fin having, on its surface, a hydrophilized layer formed from: a copolymer (A) having at least one structural unit (A1) selected from structural units (A11) derived from a polymerizable monomer having a carboxyl group and structural units (A12) derived from a polymerizable monomer having a hydroxyl group; and a structural unit (A2) derived from a monomer in which a polyoxyalkylene group and a hydrocarbon group having a polymerizable double bond are linked via an ester bond; and hydrophilic particles (B) comprising a crosslinked polymer having -COOR groups (R represents a hydrocarbon group, a hydrogen atom, an alkali metal atom, or ammonium) and a hydroxyl group.

19. The fin according to claim 18, wherein the thickness of the hydrophilic layer is 0.1 to 80 μm.

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