Surface treatment solution and hydrophilic treatment method

Abstract

Provided are: a surface treatment liquid in which a hydrophylization effect does not readily decline over time, even when a surface-treated article is exposed to various chemicals; and a hydrophilization treatment method in which the surface treatment liquid is used.　The surface treatment liquid contains a resin (A) and a solvent (S). The resin (A) contains structural units (a1) derived from a betaine monomer that has a group having an ethylenically unsaturated double bond, a cationic group, and an anionic group, the betaine monomer not including an ester bond or an amide bond. The cationic group is preferably a quaternary nitrogen cation group, and the anionic group is preferably a sulfonate anion group, a phosphonate anion group, or a carboxylate anion group.

Description

[Technical Field]

[0001] The present invention relates to a surface treatment liquid and a hydrophilization treatment method using the surface treatment liquid. [Background technology]

[0002] Conventionally, surface treatments have been performed using various surface treatment solutions to modify the surface properties of various articles. Among surface modifications, there is a great demand for making the surface of an article hydrophilic, and many hydrophilizing agents and surface treatment solutions have been proposed. By treating the surface of an object with a hydrophilizing agent or surface treatment solution, a coating is formed on the surface of the object, making the surface of the object hydrophilic.

[0003] As such hydrophilizing agents and surface treatment solutions, for example, a hydrophilizing treatment agent containing a copolymer using at least an acrylamide monomer and a mono(meth)acrylate monomer as components for exhibiting hydrophilicity (Patent Document 1), and a hydrophilizing treatment agent containing a block copolymer of a polyvinyl alcohol resin block having a mercapto group and a polyanion resin block obtained by polymerizing a polymerizable monomer having at least one carboxy group and / or sulfonic acid group in one molecule, and polyacrylic acid (Patent Document 2) have been proposed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5437523 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-126948 Summary of the Invention [Problem to be solved by the invention]

[0005] Surface treatment targets, such as windows and mirrors, may be exposed to chemicals, such as detergents, used during cleaning. Windows and mirrors, especially those used around water, are often exposed to acidic detergents used to remove limescale and basic detergents used to remove mold. Regardless of the pH of the detergent, various detergents, including soaps and shampoos, contain various ionic surfactants, such as sodium fatty acids, sodium dodecyl sulfate (SDS), and sodium linear alkyl ether sulfonate. Furthermore, detergents may contain organic acids or organic bases that can generate anions or cations with hydrophobic moieties, such as oleic acid, behenic acid, dimethylstearylamine, and dimethyl coconutamine.

[0006] However, when an article that has been surface-treated with a conventional hydrophilic treatment agent described in Patent Documents 1 and 2, etc., is exposed to a cleaning agent containing an acid, an alkali, various ionic surfactants, or an organic acid or organic base that can generate an anion or cation having a hydrophobic moiety, there is a problem in that the hydrophilicity of the surface of the surface-treated article may gradually decrease over time.

[0007] The present invention has been made in view of the above-mentioned problems, and aims to provide a surface treatment solution whose hydrophilicity effect is not likely to decrease over time even when a surface-treated article is exposed to various chemicals, and a surface treatment method using the surface treatment solution. [Means for solving the problem]

[0008] The present inventors have discovered that the above-mentioned problems can be solved by a surface treatment solution comprising a resin (A) and a solvent (S), wherein the resin (A) contains a structural unit (a1) derived from a betaine monomer that has a group having an ethylenically unsaturated double bond, a cationic group, and an anionic group, and that does not contain an ester bond or an amide bond, and have thereby completed the present invention. More specifically, the present invention provides the following.

[0009] A first aspect of the present invention is a surface treatment liquid comprising a resin (A) and a solvent (S), wherein the resin (A) comprises a structural unit (a1) derived from a betaine monomer that has a group having an ethylenically unsaturated double bond, a cationic group, and an anionic group, and that does not contain an ester bond or an amide bond.

[0010] A second aspect of the present invention is a hydrophilization treatment method for hydrophilizing the surface of a treatment target object, the method comprising applying the surface treatment liquid according to the first aspect to the surface of the treatment target object to form a coating film. [Effects of the Invention]

[0011] The present invention can provide a surface treatment solution whose hydrophilizing effect is not likely to decrease over time even when the surface-treated article is exposed to various chemicals, and a surface treatment method using the surface treatment solution. DETAILED DESCRIPTION OF THE INVENTION

[0012] <Surface treatment liquid> The surface treatment liquid contains a resin (A) and a solvent (S), and can hydrophilize the surface of an object to be treated. The optional components and essential components of the surface treatment solution will be described below.

[0013] [Resin (A)] The resin (A) contains a structural unit (a1) derived from a betaine monomer that contains a group having an ethylenically unsaturated double bond, a cationic group, and an anionic group, and that does not contain an ester bond or an amide bond. The resin (A) may contain structural units other than the structural unit (a1) as long as the object of the present invention is not impaired.

[0014] (Structural unit (a1)) The resin (A) contains a structural unit (a1) derived from a betaine monomer (hereinafter simply referred to as "betaine monomer") that has a group having an ethylenically unsaturated double bond, a cationic group, and an anionic group, but does not contain an ester bond or an amide bond, for the purpose of imparting hydrophilicity to the surface of an object to be treated by surface treatment.

[0015] The cationic group and anionic group contained in the betaine monomer act as hydrophilic groups in the resin (A). The surface of a surface-treated object may come into contact with a cleaning solution containing a large amount of anions having hydrophobic groups or cations having hydrophobic groups. When the resin in the surface treatment solution has only anionic groups such as carboxyl groups, carboxylate groups, sulfonic acid groups, and sulfonate groups as hydrophilic groups, these hydrophilic groups may no longer function as hydrophilic groups due to interaction with cations having hydrophobic groups. Furthermore, when the resin in the surface treatment solution has only cationic groups such as quaternary ammonium groups as hydrophilic groups, the cationic groups may no longer function as hydrophilic groups due to interaction with anions having hydrophobic groups. However, when the resin (A) has both cationic groups and anionic groups as hydrophilic groups, either the cationic group or the anionic group can maintain its function as a hydrophilic group, even when the surface of the treated object comes into contact with a cleaning agent rich in cations having hydrophobic groups, or a cleaning agent rich in anions having hydrophobic groups, and the hydrophilicity of the surface of the treated object is unlikely to decrease. Therefore, by forming a coating on the surface of the object to be treated using the surface treatment liquid, the contact angle of water on the surface of the surface-treated article can be made 20° or less, or even 15° or less.

[0016] The betaine monomer that gives the structural unit (a1) has an ester bond (R 01 -COO-R 02 ) and amide bond (R 03 -CONH-R 04 ) does not contain any of the following. 01 , and R 03 is a hydrogen atom or an organic group. 02 , and R 04 is an organic group. When a betaine monomer has an ester bond or an amide bond, at least a part of the ester bond or the amide bond in a resin having a structural unit derived from such a betaine monomer is hydrolyzed by the action of an acid or an alkali. Therefore, when a surface treatment is performed using a surface treatment solution containing such a resin, the hydrophilization effect is likely to be reduced when the surface-treated article comes into contact with a cleaning agent containing an acid or an alkali. On the other hand, when a betaine monomer does not contain an ester bond or an amide bond, hydrolysis of the ester bond or the amide bond due to the action of an acid or an alkali is suppressed, and the reduction in the hydrophilic effect is suppressed. For example, when a surface treatment liquid containing a resin (A) having a structural unit derived from a betaine monomer having a cationic group and an anionic group is used, the water contact angle of the surface of the surface-treated article, measured after immersing the surface-treated article in a chemical solution containing an acid or alkali for 24 hours, can be reduced to 20° or less, or even 15° or less.

[0017] There are no particular limitations on the number of cationic groups and the number of anionic groups in the betaine monomer that provides the structural unit (a1). In the betaine monomer that provides the structural unit (a1), it is preferable that the number of cationic groups and the number of anionic groups are the same. Because the betaine monomer that provides the structural unit (a1) is easy to synthesize and obtain, it is preferable that the number of cationic groups and the number of anionic groups in the betaine monomer that provides the structural unit (a1) are each 1.

[0018] In the betaine monomer that provides the structural unit (a1), for example, it is preferable that a group having an ethylenically unsaturated double bond, a cationic group, and an anionic group are bonded in this order, optionally via a linking group.

[0019] Preferably, the cationic group is a cationic group that is a quaternary nitrogen cation. The anionic group is preferably a sulfonate anionic group, a phosphonate anionic group, or a carboxylate anionic group.

[0020] In the betaine monomer that provides the structural unit (a1), examples of the group having an ethylenically unsaturated double bond include alkenyl groups such as vinyl, 1-propenyl, 2-n-propenyl (allyl), 1-n-butenyl, 2-n-butenyl, and 3-n-butenyl. Of these groups, vinyl and 2-n-propenyl (allyl) are preferred. The number of ethylenically unsaturated double bonds in the betaine monomer that provides the structural unit (a1) is not particularly limited, but one or two is preferred. The betaine monomer that provides the structural unit (a1) does not contain an ester bond or an amide bond, and therefore does not contain a (meth)acryloyl group as a group having an ethylenically unsaturated double bond. In this specification, "(meth)acrylic" refers to both "acrylic" and "methacrylic."

[0021] Examples of the betaine monomer include monomers represented by the following formula (a1-1) or (a1-2). [ka] (In formula (a1-1), R 1 is a hydrocarbon group containing an ethylenically unsaturated double bond, R 2 is a divalent hydrocarbon group having from 1 to 10 carbon atoms, R is an anionic group, Ring A is a heterocycle. [ka] (In formula (a1-2), R 3 , R 4 and R 5 are each independently a hydrocarbon group having an ethylenically unsaturated double bond or a hydrocarbon group having from 1 to 10 carbon atoms, R 3 , R 4 and R 5at least one of which is a hydrocarbon group having an ethylenically unsaturated double bond, R 6 is a divalent hydrocarbon group having from 1 to 10 carbon atoms, R is an anionic group.

[0022] In formula (a1-1), R 1 Examples of the hydrocarbon group containing an ethylenically unsaturated double bond as the ethylenically unsaturated double bond include the same groups as those having an ethylenically unsaturated double bond.

[0023] In formula (a1-1), R 2 Examples of the divalent hydrocarbon group as include an alkylene group, an arylene group, and a group formed by combining an alkylene group and an arylene group, with an alkylene group being preferred. R 2 Specific preferred examples of the alkylene group as the alkylene group include a methylene group, an ethane-1,2-diyl group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, and a decane-1,10-diyl group.

[0024] In formula (a1-1), the heterocycle as ring A may be either an aromatic heterocycle or an aliphatic heterocycle. Examples of the aromatic heterocycle include nitrogen-containing aromatic heterocycles such as an imidazole ring, a pyrazole ring, a 1,2,3-triazole ring, a 1,2,4-triazole ring, a pyridine ring, a pyrimidine ring, a pyridazine ring, and a pyrazine ring, in which any one nitrogen atom in the nitrogen-containing aromatic heterocycle is quaternized. Examples of the aliphatic heterocycle include nitrogen-containing heterocycles such as pyrrolidine ring, piperidine ring and piperazine ring, in which any one nitrogen atom in the nitrogen-containing heterocycle is quaternized.

[0025] In formula (a1-2), R 3 ~R 5Examples of the hydrocarbon group containing an ethylenically unsaturated double bond as the ethylenically unsaturated double bond include the same groups as those having an ethylenically unsaturated double bond.

[0026] In formula (a1-2), R 3 ~R 5 Examples of the hydrocarbon group include an alkyl group, an aryl group, and an aralkyl group, with an alkyl group being preferred. R 3 ~R 5 The hydrocarbon group represented by R may have a substituent. 3 ~R 5 The substituents that the hydrocarbon group may have are not particularly limited as long as they do not impair the object of the present invention. Examples of the substituents include a halogen atom, a hydroxyl group, an alkoxy group having from 1 to 4 carbon atoms, an acyl group having from 2 to 4 carbon atoms, an acyloxy group having from 2 to 4 carbon atoms, an amino group, and an alkylamino group substituted with one or two alkyl groups having from 1 to 4 carbon atoms. R 3 ~R 5 Specific preferred examples of the alkyl group as the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, and an n-decyl group.

[0027] In formula (a1-2), R 6 Examples of the divalent hydrocarbon group as include an alkylene group, an arylene group, and a group formed by combining an alkylene group and an arylene group, with an alkylene group being preferred. R 6 Specific preferred examples of the alkylene group as the alkylene group include a methylene group, an ethane-1,2-diyl group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, and a decane-1,10-diyl group.

[0028] As the betaine monomer in which the anionic group is a sulfonate anionic group, a monomer represented by the following formula (a1-3) or formula (a1-4) is preferred because of ease of synthesis and availability. [ka] (In formula (a1-3), R 1 , R 2 and ring A is R in formula (a1-1). 1 , R 2 and ring A.) [ka] (In formula (a1-4), R 3 , R 4 , R 5 and R 6 is R in formula (a1-2) 3 , R 4 , R 5 and R 6 is the same as

[0029] Examples of the monomer represented by the above formula (a1-3) or formula (a1-4) include monomers represented by the following formula (a1-5), (a1-6) or (a1-7). [ka] (In formulas (a1-5), (a1-6) and (a1-7), R 2 is R in formula (a1-3) 2 is similar to R 5 and R 6 is R in formula (a1-4) 5 and R 6 is similar to R 11 and R 12 are each independently a hydrogen atom or a methyl group, and R 13 and R 14 are each independently a single bond or an alkylene group having 1 to 4 carbon atoms.

[0030] In formulae (a1-5), (a1-6) and (a1-7), R 13 and R 14 Examples of the alkylene group having 1 to 4 carbon atoms include a methylene group, an ethane-1,2-diyl group, a propane-1,3-diyl group, a propane-1,2-diyl group, and a butane-1,4-diyl group.

[0031] Examples of betaine monomers in which the anionic group is a phosphonate anion group or a carboxylate anion group include monomers represented by the above formula (a1-3) or (a1-4), and monomers represented by the above formula (a1-5), (a1-6), or (a1-7) in which the sulfonate anion group (-SO3 - ) is a phosphonate anion group (-(PO3) 2- ) and carboxylate anion groups (-COO - ) is a monomer replaced by

[0032] Specific examples of betaine monomers that provide the structural unit (a1) include compounds of the following formula and compounds of the following formula that contain a sulfonate anion group (-SO3 - ) is a phosphonate anion group (-(PO3) 2- ) and carboxylate anion groups (-COO - ) is a monomer replaced by [ka]

[0033] The betaine monomer that provides the structural unit (a1) can be synthesized by a known reaction. For example, it can be obtained by reacting a compound having a group with an ethylenically unsaturated double bond and a group that becomes a cationic group with a compound having an anionic group. As a specific example, the compound represented by formula (a1-3) can be obtained by reacting the following compound with sultone in a solvent. Examples of sultones include sultones with a 4- to 10-membered ring, with 1,3-propane sultone and 1,4-butane sultone being preferred. [ka] (In the formula, R 1 is R in (a1-1) above 1 and ring A is a heterocycle.

[0034] The structural unit (a1) contained in the resin (A) may be of one type or two or more types.

[0035] The ratio of the structural unit (a1) to all structural units constituting the resin (A) is not particularly limited as long as it does not impair the object of the present invention. The ratio of the structural unit (a1) to all structural units constituting the resin (A) is preferably, for example, 70 mol% or more. The ratio of the structural unit (a1) to all structural units constituting the resin (A) may be 80 mol% or more, 85 mol% or more, 90 mol% or more, 94 mol% or more, or 100 mol%. The ratio of the structural unit (a1) is not particularly limited, but may be 100 mol% or less.

[0036] (Structural unit (a2)) The resin (A) may contain, in addition to the aforementioned structural unit (a1), a structural unit (a2) other than the structural unit (a1). The structural unit (a2) may or may not contain a hydrophilic group. Examples of the structural unit (a2) having a hydrophilic group include structural units that have a hydrophilic group and an ethylenically unsaturated double bond and are derived from monomers other than the aforementioned betaine monomers.

[0037] Such a hydrophilic group is not particularly limited as long as it is a group that is generally recognized as a hydrophilic group by those skilled in the art. Specific examples of hydrophilic groups include primary amino groups, secondary amino groups, carboxy groups, phenolic hydroxyl groups, sulfonic acid groups, polyoxyalkylene groups (e.g., polyoxyethylene groups, polyoxypropylene groups, polyoxyalkylene groups in which oxyethylene groups and oxypropylene groups are blocked or randomly bonded, etc.), and alcoholic hydroxyl groups.

[0038] The ratio of the structural unit (a2) to all structural units constituting the resin (A) is not particularly limited as long as the desired surface treatment effect can be obtained. When the structural unit (a2) is contained, the ratio of the structural unit (a2) to all structural units constituting the resin (A) is, for example, preferably from 0.01 mol% to 30 mol%, and more preferably from 0.1 mol% to 15 mol%.

[0039] From the standpoint of resistance to the above-mentioned acids and other chemicals, it is preferable that the structural unit (a2) contain neither an ester bond nor an amide bond. When the structural unit (a2) contains an ester bond or an amide bond, the proportion of the structural unit (a2) containing an ester bond or an amide bond relative to all structural units constituting the resin (A) is, for example, preferably 10 mol % or less, and more preferably 6 mol % or less.

[0040] (adhesive group) The resin (A) preferably has an adhesive group for the purpose of improving the adhesion between the surface of the object to be treated and the resin (A). The adhesive group is not particularly limited as long as it improves the adhesion of the resin (A) to the surface of the object to be treated. Preferred examples of the adhesive group include -SiR 7 a R 8 3-a (In the formula, R 7 is a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, and R 8 is a hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and a is an integer of 1 to 3. Examples include -NH2 and -PO3H. Resin (A) is -SiR 7 a R 8 3-a By having adhesive groups such as -NH2 or -PO3H, it is easy to prevent the surface of an article treated with a surface treatment agent from losing its hydrophilicity due to friction. The bonding position of the adhesive group in the resin (A) is not particularly limited, but it is preferably bonded to the molecular chain terminal of the resin (A).

[0041] -SiR 7a R 8 3-a is a reactive silyl group, and contains a silanol group (hydroxyl group) or a group that generates a silanol group upon hydrolysis (alkoxy group and halogen atom). 7 a R 8 3-a When the surface treatment is performed using a surface treatment solution containing a resin (A) having the formula: 7 a R 8 3-a Therefore, the resin (A) is firmly bonded to the surface of the object to be treated, and the decrease in hydrophilicity of the surface of the object to be treated due to friction is suppressed. In terms of the reactivity between the reactive silyl group and the surface of the object to be treated, a is preferably 2 or 3, and more preferably 3. When a is 2 or 3, the -SiR 7 a R 8 3-a As a result, a network of siloxane bonds is formed in the coating that extends along the surface of the object to be treated, making it easier to bond resin (A) particularly firmly to the surface of the object to be treated.

[0042] When resin (A) has -NH2 or -PO3H as an adhesive group, it is thought that resin (A) is firmly bonded to the surface of the object to be treated due to interactions such as water bonds between the surface of the object to be treated and these adhesive groups.

[0043] -SiR 7 a R 8 3-a In R 7 The halogen atom as is, for example, a chlorine atom, a bromine atom, an iodine atom, etc., and a chlorine atom is preferred. R 7 Preferred examples of the alkoxy group as include a methoxy group, an ethoxy group, an n-propyloxy group, an isopropyloxy group, and an n-butyloxy group, with a methoxy group and an ethoxy group being more preferred.

[0044] -SiR 7 a R 8 3-a In R 8 The hydrocarbon group as R is preferably an alkyl group, an aralkyl group, or an aryl group. 8 When is an alkyl group, it preferably has 1 or more and 6 or less, more preferably 1 or more and 4 or less, and more preferably 1 or 2 carbon atoms. R 8 When is an alkyl group, preferred examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an n-butyl group, with a methyl group and an ethyl group being more preferred. As the aralkyl group, a benzyl group and a phenethyl group are preferred. As the aryl group, a phenyl group, a naphthalen-1-yl group, and a naphthalen-2-yl group are preferred, and a phenyl group is more preferred.

[0045] -SiR 7 a R 8 3-a Preferred examples of the silyl group include a trimethoxysilyl group, a triethoxysilyl group, a tri-n-propyloxysilyl group, a methyldimethoxysilyl group, an ethyldimethoxysilyl group, a methyldiethoxysilyl group, and an ethyldiethoxysilyl group, and more preferred are a trimethoxysilyl group and a triethoxysilyl group.

[0046] -SiR 7 a R 8 3-a is preferably introduced into the resin (A) as a group represented by the following formula (1) because it is easy to introduce into the resin (A). -SR 21 -SiR 7 a R 8 3-a ···(1) (In formula (1), R 21 is a divalent hydrocarbon group having 1 to 20 carbon atoms, and R 7 , R8 , and a are -SiR 7 a R 8 3-a R in 7 , R 8 , and a.)

[0047] In the above formula (1), R 21 The divalent hydrocarbon group as the alkyl group preferably has 1 or more and 10 or less carbon atoms, more preferably 1 or more and 6 or less carbon atoms, and particularly preferably 2 or more and 4 or less carbon atoms. R 21 Examples of the divalent hydrocarbon group as include an alkylene group, an arylene group, and a group formed by combining an alkylene group and an arylene group, with an alkylene group being preferred. R 21 Specific preferred examples of the alkylene group as the alkylene group include a methylene group, an ethane-1,2-diyl group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, and a decane-1,10-diyl group.

[0048] In resin (A), -SiR 7 a R 8 3-a The amount of -NH2 or -PO3H is not particularly limited as long as it does not impair the object of the present invention. In terms of the reactivity of the resin (A) with the surface of the object to be treated, -SiR 7 a R 8 3-a The total amount of -NH2 and -PO3H is preferably 0.01 mol% or more and 20 mol% or less, more preferably 0.1 mol% or more and 10 mol% or less, and even more preferably 0.1 mol% or more and 5 mol% or less, based on all structural units constituting the resin (A).

[0049] (Method for synthesizing resin (A)) Resin (A) can be prepared by polymerizing a betaine monomer that provides the structural unit (a1) and, if necessary, a monomer that provides the structural unit (a2) according to a well-known method. A preferred method is to radically polymerize the monomer that provides the structural unit that constitutes resin (A) in the presence of a polymerization initiator. Examples of the polymerization initiator include azo polymerization initiators, such as 2,2'-azobis(2-methylpropionamidine) dihydrochloride (dihydrochloride), 2,2'-azobis[2-(phenylamidino)propane]dihydrochloride, 2,2'-azobis{2-[N-(4-chlorophenyl)amidino]propane}dihydrochloride, and 2,2'-azobis{2-[N-(4-hydroxyphenyl)amidino]propane}dihydrochloride. propane}dihydrochloride, 2,2'-azobis[2-(N-benzylamidino)propane]dihydrochloride, 2,2'-azobis[2-(N-allylamidino)propane]dihydrochloride, 2,2'-azobis(2-amidinopropane)dihydrochloride, 2,2'-azobis{2-[N-(4-hydroxyethyl)amidino]propane}dihydrochloride, 2,2-azobis 2,2-Azobis[2-(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride, 2,2-Azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride, 2,2-Azobis[2-(4,5,6,7-tetrahydro-1H-1,3-diazepin-2-yl)propane]dihydrochloride, 2,2-Azobis[2-(3,4,5,6-tetrahydropyrimidine- Examples of polymerization initiators include 2,2-azobis[2-(5-hydroxy-3,4,5,6-tetrahydropyrimidin-2-yl)propane]dihydrochloride, 2,2-azobis{2-[1-(2-hydroxyethyl)-2-imidazolin-2-yl]propane}dihydrochloride, and 2,2-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride. These polymerization initiators may be used alone or in combination of two or more. The amount of polymerization initiator used is not particularly limited as long as the polymerization reaction can be carried out well. The amount of polymerization initiator used is preferably 0.1 mol % to 20 mol % and more preferably 0.1 mol % to 15 mol % based on the total number of moles of monomers.

[0050] Resin (A) is -SiR 7 a R 8 3-a, —NH2 or —PO3H, in the polymerization of the betaine monomer that provides the structural unit (a1) and, if necessary, the monomer that provides the structural unit (a2), 7 a R 8 3-a , -NH2 or -PO3H. Alternatively, a betaine monomer that provides the structural unit (a1) and, if necessary, a monomer that provides the structural unit (a2) may be polymerized, and then the resulting polymer may be terminated with -SiR 7 a R 8 3-a , -NH2 or -PO3H. For example, by causing a so-called thiol-ene reaction between a terminal vinyl group of a precursor of resin (A), which essentially contains the above-mentioned structural unit (a1) and optionally contains structural unit (a2), and a compound having a mercapto group, such as a compound represented by formula (2) below, a terminal group derived from the compound represented by formula (2) below can be introduced into resin (A). HS-R 21 -SiR 7 a R 8 3-a ···(2) (In formula (2), R 7 , R 8 , R 21 , and a are R in formula (1), respectively. 7 , R 8 , R 21 , and a.)

[0051] The mass ratio of the resin (A) to the mass of the surface treatment liquid is not particularly limited, but is preferably 0.1 mass% to 5 mass% or less, more preferably 0.1 mass% to 3.0 mass% or less, and even more preferably 0.1 mass% to 1.5 mass% or less.

[0052] <Electrolyte (B)> The surface treatment liquid may contain an electrolyte (B). When the surface treatment liquid contains the electrolyte (B), it is easy to dissolve the resin (A) uniformly and stably in the surface treatment liquid. The electrolyte (B) is a substance other than the resin (A). The resin (A) that can be ionized in the surface treatment solution is defined as the resin (A) rather than the electrolyte (B).

[0053] The type of electrolyte (B) is not particularly limited as long as it is a substance that does not decompose the resin (A). The type of electrolyte (B) is not particularly limited. The electrolyte (B) may be a substance generally considered to be a strong electrolyte, such as hydrochloric acid, sodium chloride, or potassium chloride, or may be a substance generally considered to be a weak electrolyte, such as an anionic surfactant (e.g., sodium dodecyl sulfate) or a cationic surfactant (e.g., benzalkonium chloride).

[0054] Suitable examples of the electrolyte (B) include sodium chloride, potassium chloride, sodium perchlorate, potassium perchlorate, sodium hydroxide, potassium hydroxide, perchloric acid, hydrochloric acid, and sulfuric acid, because they are easily available and inexpensive.

[0055] The content of the electrolyte (B) is not particularly limited as long as it does not impair the object of the present invention, and may be appropriately determined taking into consideration the solubility in the surface treatment liquid, etc. The content of the electrolyte (B) is, for example, preferably 0 parts by mass or more and 700 parts by mass or less, more preferably 0 parts by mass or more and 600 parts by mass or less, and even more preferably 0 parts by mass or more and 500 parts by mass or less, relative to 100 parts by mass of the resin (A).

[0056] [Solvent (S)] The surface treatment liquid contains a solvent (S). The solvent (S) may be water, an organic solvent, or an aqueous solution of an organic solvent. As the solvent (S), water is preferred in terms of the solubility of the resin (A), the safety of the hydrophilization treatment operation, and low cost. Suitable examples of organic solvents used as the solvent (S) include alcohols. Examples of the alcohols include aliphatic alcohols, preferably alcohols having 1 to 3 carbon atoms. Specific examples include methanol, ethanol, n-propyl alcohol, and isopropyl alcohol (IPA), with methanol, ethanol, and isopropyl alcohol being preferred. These alcohols may be used alone or in combination of two or more.

[0057] The water content in the solvent (S) is preferably 50% by mass or more, more preferably 80% by mass or more, and particularly preferably 100% by mass.

[0058] [Other ingredients] The surface treatment solution may contain various additives to the extent that the object of the present invention is not impaired. Examples of such additives include a thermal polymerization inhibitor, a photopolymerization inhibitor, an antioxidant, an ultraviolet absorber, a colorant, an antifoaming agent, and a viscosity modifier. The content of these additives is determined appropriately taking into account the amounts typically used of these additives.

[0059] <Hydrophilic treatment method> The hydrophilization treatment method is not particularly limited as long as it is a method that can bond or adhere the resin (A) to the surface of the object to be treated so that the surface of the object to be treated is hydrophilized to a desired degree. Typically, the hydrophilization treatment method includes applying the above-mentioned surface treatment liquid to form a coating on the surface of the object to be treated, although it is not necessary to form a uniform coating over the entire surface of the object to be hydrophilized, as long as the surface of the object to be treated is hydrophilized to the desired degree. The hydrophilic treatment method preferably further includes rinsing the surface of the object to be treated with a rinse liquid after the application of the surface treatment liquid.

[0060] Hereinafter, applying a surface treatment liquid to form a coating on the surface of the treatment target object will also be referred to as a “coating step.” Furthermore, rinsing the surface of the treatment target object with a rinse liquid after applying the surface treatment liquid will also be referred to as a “rinsing step.” The coating step, rinsing step, and surface treatment solution will be described in detail below.

[0061] <Coating process> In the coating step, the surface treatment liquid is applied to the surface of the object to be treated to form a coating. The coating method is not particularly limited. Specific examples of the coating method include spin coating, spraying, roller coating, immersion, etc. When the object to be treated is a substrate, spin coating is preferred as the coating method because it is easy to form a coating with a uniform thickness evenly on the surface of the substrate.

[0062] The material of the surface of the object to be treated onto which the surface treatment liquid is applied is not particularly limited, and may be an organic material or an inorganic material. Examples of organic materials include various resin materials such as polyester resins such as PET resin and PBT resin, various nylons, polyimide resins, polyamide-imide resins, polyolefins such as polyethylene and polypropylene, polystyrene, (meth)acrylic resins, cycloolefin polymers (COP), cycloolefin copolymers (COC), and silicone resins (e.g., polyorganosiloxanes such as polydimethylsiloxane (PDMS)). Furthermore, photosensitive resin components contained in various resist materials and alkali-soluble resin components are also preferred as organic materials. Inorganic materials include glass, silicon, and various metals such as copper, aluminum, iron, tungsten, etc. The metals may be alloys.

[0063] The shape of the object to be processed is not particularly limited, and may be flat or may have a three-dimensional shape such as a sphere or a column.

[0064] The treated object may be exposed to chemicals such as cleaning agents, and there is a concern that the exposure to chemicals may reduce the hydrophilicity of the coating formed on the treated object. However, by using the above-described surface treatment liquid, it is possible to suppress the reduction in hydrophilicity when the surface-treated surface comes into contact with various chemicals. Therefore, by using the treated object as the treated object, which is often exposed to chemicals such as cleaning agents, such as glass members included in windows, mirrors, furniture, and optical devices (e.g., devices having lenses), or translucent resin members, the effect of chemical resistance regarding hydrophilicity can be particularly exhibited.

[0065] After the surface treatment liquid has been applied to the surface of the treatment target, at least a portion of the solvent (S) may be removed from the coating made of the surface treatment liquid by a known drying method, if necessary.

[0066] The thickness of the coating formed in the coating step is not particularly limited, and is, for example, preferably 1 μm or less, more preferably 300 nm or less, and even more preferably 100 nm or less.

[0067] The thickness of the coating formed by the coating step can be adjusted by adjusting the solid content concentration of the surface treatment liquid, coating conditions, etc.

[0068] <Rinse process> In the rinsing step, after the application of the surface treatment liquid, the surface of the object to be treated is rinsed with a rinse liquid, which can reduce the thickness of the coating formed on the surface of the object to be treated. The rinse liquid is not particularly limited as long as it can form a coating of the desired thickness. Water, an organic solvent, or an aqueous solution of an organic solvent can be used as the rinse liquid. Water is preferred as the rinse liquid. The method for rinsing the coating is not particularly limited, but typically, rinsing is carried out by contacting the coating with a rinse liquid in the same manner as in the coating method described above.

[0069] Before rinsing, the coating may be heated to remove part or all of the solvent (S) contained in the coating. The heating temperature is not particularly limited as long as it does not cause deterioration or decomposition of the object to be treated or the resin (A). Typical heating temperatures include temperatures of about 50°C or higher and 300°C or lower. The heating time is not particularly limited, and is, for example, 5 seconds or higher and 24 hours or lower, and preferably 10 seconds or higher and 6 hours or lower.

[0070] The thickness of the coating obtained after rinsing is, for example, preferably 10 nm or less, more preferably 0.1 nm to 10 nm, even more preferably 0.1 nm to 8 nm, even more preferably 0.5 nm to 5 nm, and particularly preferably 0.5 nm to 3 nm.

[0071] The thickness of the coating can be adjusted by adjusting the solids concentration of the surface treatment liquid, the application conditions, the amount of rinse liquid used, the type of rinse liquid, the temperature of the rinse liquid, and the like.

[0072] After rinsing, the object to be treated may be dried as necessary, and then the object to be treated is suitably used for various purposes. [Example]

[0073] The present invention will be explained in more detail below by showing examples, but the scope of the present invention is not limited to these examples.

[0074] [Preparation Example 1] Preparation of betaine monomer BM1 The betaine monomer BM1 was obtained by reacting 1-vinylimidazole with 1,4-butanesultone in acetonitrile. [ka]

[0075] [Preparation Example 2] Preparation of betaine monomer BM2 The betaine monomer BM2 was obtained by reacting 4-vinylpyridine with 1,4-butanesultone in acetonitrile. [ka]

[0076] [Preparation Example 3] Preparation of betaine monomer BM3 The betaine monomer BM3 was obtained by reacting diallylmethylamine with 1,3-propanesultone in acetonitrile. [ka]

[0077] [Preparation Example 4] Preparation of betaine monomer BM4 The betaine monomer BM4 was obtained by reacting 2-vinylpyridine with 1,4-butanesultone in acetonitrile. [ka]

[0078] [Preparation Examples 4 to 15] Preparation of Resins A1 to A11 The types and amounts (mmol) of monomers and polymerization initiators shown in Tables 1 and 2 were prepared into aqueous solutions with a monomer concentration of 30% by mass, and radical polymerization was carried out at 80°C for 6 hours to obtain resin solutions 1 to 13 shown in Tables 1 and 2 as aqueous resin solutions or suspensions. The raw materials for resin synthesis listed in Tables 1 and 2 are BM1 to BM4 above, C1 to C2, AD1 to AD4, and Init 1 below. AD1: 3-(methacryloyloxy)propyltrimethoxysilane AD2: 3-(trimethoxysilyl)propanethiol AD3: 3-amino-5-mercapto-1,2,4-triazole AD4: 4,6-diamino-2-mercaptopyrimidine C1: Acrylic acid C2: N-[2-(dimethylamino)ethyl]acrylamide Init 1: 2,2'-Azobis(2-methylpropionamidine) dihydrochloride

[0079] [Table 1]

[0080] [Table 2]

[0081] [Examples 1 to 11 and Comparative Examples 1 to 3] A surface treatment liquid was obtained using the types of resin liquid, electrolyte, and water listed in Tables 3 and 4 so that the resin and electrolyte had concentrations listed in Tables 3 and 4. In Comparative Example 6, the following resin P1 was used as the resin liquid. The electrolytes listed in Tables 3 and 4 are as follows: P1: Poly(diallyldimethylammonium chloride) (Sigma-Aldrich, mass-average molecular weight Mw 400,000 to 500,000) B1: Sodium chloride

[0082] Using the surface treatment solutions obtained in Examples 1 to 11 and Comparative Examples 1 to 3, the hydrophilization treatment was evaluated according to the following evaluation methods 1 to 6. The evaluation results are shown in Tables 3 and 4.

[0083] <Evaluation 1> Initial water contact angle A silicon wafer was used as the object to be processed. The silicon wafer was immersed in the surface treatment solution at room temperature for 1 minute. After the silicon wafer was removed from the surface treatment solution, it was heat-treated at 180°C for 5 minutes. The silicon wafer was cooled to room temperature and then rinsed with pure water. After drying the rinsed silicon wafer, the film thickness of the coating formed on the silicon wafer surface was measured by spectroscopic ellipsometry. As a result, the thickness of the coating was 2 nm in all of Examples 1 to 11 and Comparative Examples 1 to 3. The water contact angle of the coating formed on the surface of the silicon wafer was evaluated by the following method.

[0084] (Contact angle evaluation) A droplet of pure water (2.0 μL) was dropped onto the surface of the treated silicon wafer using a Dropmaster 700 (Kyowa Interface Science Co., Ltd.), and the contact angle of water was measured as the contact angle 10 seconds after the drop. The average values ​​of the contact angles of water at three points on the silicon wafer are shown in Tables 3 and 4.

[0085] <Evaluation 2> Alkaline resistance test In the same manner as in Evaluation 1, the surface of the silicon wafer was treated with the surface treatment liquid. The surface-treated silicon wafer was then immersed in an aqueous sodium hydroxide solution of pH 12 at room temperature for 24 hours. After the silicon wafer was removed from the aqueous sodium hydroxide solution, the surface was air-blowed to remove the aqueous sodium hydroxide solution from the surface of the silicon wafer, followed by rinsing with water and evaluation of the water contact angle in the same manner as in Evaluation 1.

[0086] <Evaluation 3> Acid resistance test In the same manner as in Evaluation 1, the surface of the silicon wafer was treated with the surface treatment liquid. The surface-treated silicon wafer was then immersed for 24 hours at room temperature in an aqueous sulfuric acid solution with a pH of 1. The surface of the silicon wafer was removed from the aqueous sulfuric acid solution by air blowing to remove the sulfuric acid from the surface of the silicon wafer, and then the silicon wafer was rinsed with water and evaluated for water contact angle in the same manner as in Evaluation 1.

[0087] <Evaluation 4> SDS (sodium dodecyl sulfate) tolerance test In the same manner as in Evaluation 1, the surface of the silicon wafer was treated with the surface treatment liquid. The surface-treated silicon wafer was then immersed in a 1% by mass aqueous solution of SDS at room temperature for 24 hours. After the silicon wafer was removed from the aqueous solution, the surface was air-blowed to remove the SDS solution from the surface of the silicon wafer, followed by rinsing with water. The water contact angle was evaluated in the same manner as in Evaluation 1.

[0088] <Evaluation 5> Tri-n-pentylamine resistance test In the same manner as in Evaluation 1, the surface of the silicon wafer was treated with the surface treatment liquid. The surface-treated silicon wafer was then immersed in a 0.5% by mass aqueous solution of tri-n-pentylamine at room temperature for 24 hours. After the silicon wafer was removed from the aqueous solution, air was blown onto the surface of the silicon wafer to remove the tri-n-pentylamine solution from the surface of the silicon wafer. The silicon wafer was then rinsed with water and the water contact angle was evaluated in the same manner as in Evaluation 1.

[0089] <Evaluation 6> Scratch resistance test In the same manner as in Evaluation 1, the surface of the silicon wafer was treated with the surface treatment liquid. Next, the surface-treated silicon wafer was subjected to a rubbing test using a 2 cm square Scotch-Brite antibacterial urethane (manufactured by 3M) with a load of 2 kg and 10 strokes back and forth. After the rubbing test, the silicon wafer was evaluated for water contact angle in the same manner as in Evaluation 1.

[0090] [Table 3]

[0091] [Table 4]

[0092] Examples 1 to 11 show that when a surface treatment liquid is used that contains a resin (A) and a solvent (S), where the resin (A) contains a structural unit (a1) derived from a betaine monomer that has a group having an ethylenically unsaturated double bond, a cationic group, and an anionic group, and that does not contain an ester bond or an amide bond, the hydrophilicity is unlikely to decrease even when the surface treatment liquid comes into contact with various chemicals. In addition, according to the surface treatment solutions of Examples 1 to 6, 10 and 11, the resin (A) is -SiR 7 a R 8 3-a It can also be seen that when the surface has an adhesive group such as -NH2, the hydrophilic effect is not impaired even when the surface of the surface-treated object is rubbed.

[0093] On the other hand, the surface treatment solutions of Comparative Examples 1 to 3 show that when the resin (A) does not contain the structural unit (a1) derived from a betaine monomer that has a group having an ethylenically unsaturated double bond, a cationic group, and an anionic group, but does not contain an ester bond or an amide bond, the chemical resistance of either of these is poor. Furthermore, in Comparative Examples 1 and 2, the initial contact angle is also high, making it difficult to achieve the desired hydrophilic effect.

Claims

1. A composition comprising a resin (A) and a solvent (S), The resin (A) is prepared by polymerizing a betaine monomer having a group having an ethylenically unsaturated double bond, a cationic group, and an anionic group, and not containing an ester bond or an amide bond, and then forming a —SiR ７ ａ R ８ ３－ａ (In the formula, R ７ is a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom; R ８ represents a hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and a represents an integer of 1 to 3, or —NH ２ is a resin that can be prepared by introducing The surface treatment solution, wherein the betaine monomer is a monomer represented by the following formula (a1-1) or (a1-2): 【Chemistry 1】 (In formula (a1-1), R １ is a hydrocarbon group containing an ethylenically unsaturated double bond, R ２ is a divalent hydrocarbon group having from 1 to 10 carbon atoms, R is an anionic group, Ring A is a heterocycle. 【Chemistry 2】 (In formula (a1-2), R ３ , R ４ and R ５ each independently represents a hydrocarbon group having an ethylenically unsaturated double bond or a hydrocarbon group having from 1 to 10 carbon atoms, R ３ , R ４ and R ５ at least one of which is a hydrocarbon group having an ethylenically unsaturated double bond, R ６ is a divalent hydrocarbon group having from 1 to 10 carbon atoms, R is an anionic group.

2. The surface treatment solution according to claim 1 , wherein the cationic group is a quaternary nitrogen cationic group.

3. 3. The surface treatment liquid according to claim 1, wherein the anionic group is a sulfonate anion group, a phosphonate anion group, or a carboxylate anion group.

4. The surface treatment solution according to any one of claims 1 to 3, wherein the betaine monomer is a monomer represented by the following formula (a1-3) or formula (a1-4): 【Transformation 3】 (In formula (a1-3), R １ , R ２ and ring A is R in formula (a1-1). １ , R ２ and ring A. 【Chemistry 4】 (In formula (a1-4), R ３ , R ４ , R ５ and R ６ is R in formula (a1-2). ３ , R ４ , R ５ and R ６ (Similar to the above.)

5. The surface treatment solution according to any one of claims 1 to 4, further comprising an electrolyte (B).

6. 6. The surface treatment solution according to claim 5, wherein the electrolyte (B) contains at least one selected from the group consisting of sodium chloride, potassium chloride, sodium perchlorate, potassium perchlorate, sodium hydroxide, potassium hydroxide, perchloric acid, sulfuric acid, and hydrochloric acid.

7. The surface treatment solution according to any one of claims 1 to 6, wherein the solvent (S) contains water.

8. A composition comprising a resin (A) and a solvent (S), the resin (A) comprises a structural unit (a1) derived from a betaine monomer that has a group having an ethylenically unsaturated double bond, a cationic group, and an anionic group, and that does not contain an ester bond or an amide bond; the proportion of the structural unit (a1) relative to all structural units constituting the resin (A) is 70 mol % or more, The betaine monomer is a monomer represented by the following formula (a1-1) or (a1-2): The resin (A) is a surface treatment liquid having -SiR 7 a R 8 3-a (wherein R 7 is a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom, R 8 is a hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and a is an integer of 1 to 3), or -NH 2 . 【Transformation 5】 (In formula (a1-1), R １ is a hydrocarbon group containing an ethylenically unsaturated double bond, R ２ is a divalent hydrocarbon group having from 1 to 10 carbon atoms, R is an anionic group, Ring A is a heterocycle. 【Transformation 6】 (In formula (a1-2), R ３ , R ４ and R ５ each independently represents a hydrocarbon group having an ethylenically unsaturated double bond or a hydrocarbon group having from 1 to 10 carbon atoms, R ３ , R ４ and R ５ at least one of which is a hydrocarbon group having an ethylenically unsaturated double bond, R ６ is a divalent hydrocarbon group having from 1 to 10 carbon atoms, R is an anionic group.

9. A hydrophilization treatment method for hydrophilizing the surface of a treatment target, comprising applying the surface treatment liquid according to any one of claims 1 to 8 to form a coating on the surface of the treatment target.

10. 10. The hydrophilization treatment method according to claim 9, further comprising rinsing the surface of the object with a rinse liquid after applying the surface treatment liquid.

11. 11. The hydrophilization treatment method according to claim 9, wherein the object to be treated is a glass member or a translucent resin member provided in a window, a mirror, furniture, or an optical device.

12. A hydrophilization treatment method for hydrophilizing the surface of a treatment object, comprising applying a surface treatment liquid to form a coating on the surface of the treatment object, the surface treatment liquid contains a resin (A) and a solvent (S), the resin (A) is a resin comprising a structural unit (a1) derived from a betaine monomer that has a group having an ethylenically unsaturated double bond, a cationic group, and an anionic group, and that does not contain an ester bond or an amide bond; or This resin can be prepared by polymerizing the betaine monomer and then introducing -SiR 7 a R 8 3-a (wherein R 7 is a hydroxyl group, an alkoxy group having from 1 to 4 carbon atoms, or a halogen atom, R 8 is a hydrocarbon group having from 1 to 10 carbon atoms which may have a substituent, and a is an integer of 1 to 3) or -NH 2 to the end of the resulting polymer, The betaine monomer is a monomer represented by the following formula (a1-1) or (a1-2): 【Transformation 7】 (In formula (a1-1), R 1 is a hydrocarbon group containing an ethylenically unsaturated double bond; R 2 is a divalent hydrocarbon group having from 1 to 10 carbon atoms; R is an anionic group, Ring A is a heterocycle. 【Transformation 8】 (In formula (a1-2), R 3 , R 4 and R 5 each independently represent a hydrocarbon group having an ethylenically unsaturated double bond or a hydrocarbon group having from 1 to 10 carbon atoms; at least one of R 3 , R 4 and R 5 is a hydrocarbon group having an ethylenically unsaturated double bond; R 6 is a divalent hydrocarbon group having from 1 to 10 carbon atoms; R is an anionic group.

13. A hydrophilization treatment method for hydrophilizing the surface of a treatment object, comprising applying a surface treatment liquid to form a coating on the surface of the treatment object, the surface treatment liquid contains a resin (A) and a solvent (S), the resin (A) comprises a structural unit (a1) derived from a betaine monomer that has a group having an ethylenically unsaturated double bond, a cationic group, and an anionic group, and that does not contain an ester bond or an amide bond; the proportion of the structural unit (a1) relative to all structural units constituting the resin (A) is 70 mol % or more, The betaine monomer is a monomer represented by the following formula (a1-1) or (a1-2): 【Chemistry 9】 (In formula (a1-1), R 1 is a hydrocarbon group containing an ethylenically unsaturated double bond; R 2 is a divalent hydrocarbon group having from 1 to 10 carbon atoms; R is an anionic group, Ring A is a heterocycle. 【Chemistry 10】 (In formula (a1-2), R 3 , R 4 and R 5 each independently represent a hydrocarbon group having an ethylenically unsaturated double bond or a hydrocarbon group having from 1 to 10 carbon atoms; at least one of R 3 , R 4 and R 5 is a hydrocarbon group having an ethylenically unsaturated double bond; R 6 is a divalent hydrocarbon group having from 1 to 10 carbon atoms; R is an anionic group.

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