JP7227565B2 - Hydrophilic coating agent composition and hydrophilic article - Google Patents

Description

The present invention relates to hydrophilic coating compositions and hydrophilic articles.

Underwater goggles used in swimming pools, sea bathing, etc. may become cloudy during use, resulting in reduced visibility. When fogging occurs, water can be poured into the goggles to temporarily remove the fog, but water droplets adhere to the surface of the goggles at that time, reducing visibility and preventing the user from having a normal field of vision. will no longer be provided. Therefore, such articles preferably have the function of removing water droplets on the surface of the goggles.

For example, a method is known in which a conductive coating is applied to the surface of a transparent base material, and an electric current is passed through the coating to dry adhering water droplets. However, the method of applying a conductive coating to the surface of a transparent substrate and drying the attached water droplets by passing an electric current through the coating is dangerous because accidents such as a short circuit are likely to occur. In addition, such articles require electric power for driving and have a complicated configuration, resulting in high running costs. Therefore, a safe and simple method is desired.

Patent Documents 1 to 4 disclose a hydrophilic film (hydrophilic coating film) provided on the surface of an article. By covering the surface of an article with a hydrophilic film, water droplets adhering to the surface of the article are quickly changed into a water film, thereby easily and effectively preventing deterioration of visibility.

JP 2010-57690 A JP 2016-27134 A JP 2018-150470 A JP 2017-165878 A

However, the hydrophilic film made of an acrylic resin having a hydrophilic group and a hydrolyzable alkoxysilyl group, which is described in Patent Document 1, requires an intermediate layer, so there is a concern that the workability during coating will be complicated. was there. In addition, the hydrophilized films composed of specific acrylic copolymers and surfactants, which are specifically disclosed in Patent Documents 2 to 4, do not require an intermediate layer, but when repeatedly washed with water, the acrylic copolymer Since the hydrophilicity of coalescence is low, there is a concern that the hydrophilicity of the film surface is lowered due to the outflow of the surfactant, resulting in the generation of water droplets and a decrease in visibility.

In general, such a hydrophilized film as described above is also required to have adhesion to a substrate, as disclosed in Patent Documents 3 and 4 above.

The present invention has been made in view of the above circumstances, and a hydrophilic coating composition capable of forming a hydrophilic film having good adhesion to a substrate and maintaining hydrophilicity even after washing with water. The purpose is to provide goods.

（式（１）中、Ｒ^１は水素原子またはメチル基、Ｒ^２は水素原子または炭素数１～４の直鎖または分岐鎖のアルキル基である。）で表される単量体（ａ１）と、式（２）：

（式（２）中、Ｒ^３は水素原子またはメチル基、Ｒ^４は炭素数２以上６以下の直鎖または分岐鎖のアルキレン基、Ｘは酸素原子または－ＮＨ－、Ｍ^＋は水素イオンを除く一価のカチオンである。）で表される単量体（ａ２）と、式（３）：

（式（３）中、Ｒ^５は水素原子またはメチル基、Ｒ^６は炭素数１～４の直鎖または分岐鎖のアルキル基である。）で表される単量体（ａ３）と、式（４）：

（式（４）中、Ｒ^７は水素原子またはメチル基、Ｒ^８は水素原子または炭素数１～３の直鎖もしくは分岐鎖のアルキル基であり、Ｒ^９は炭素数１～３の直鎖または分岐鎖のアルキル基であり、Ｒ^８およびＲ^９はそれぞれ同一でもよく、異なっていてもよい。）で表される単量体（ａ４）を含有する単量体混合物から形成される共重合体であり、
前記単量体混合物中の、前記単量体（ａ１）の割合が０．５～７質量％であり、前記単量体（ａ２）の割合が５～３５質量％であり、前記単量体（ａ３）の割合が１０～５０質量％であり、前記単量体（ａ４）の割合が２５～７５質量％であり、
前記単量体（ａ３）に対する前記単量体（ａ２）と前記単量体（ａ４）の合計の質量比［｛（ａ２）＋（ａ４）｝／（ａ３）］が、０．５以上１０以下である親水化コーティング剤組成物、に関する。 That is, the present invention is a hydrophilic coating composition containing an acrylic copolymer (A) and a solvent (B),
The acrylic copolymer (A) has the formula (1):

(In formula (1), R ¹ is a hydrogen atom or a methyl group, and R ² is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms.) and equation (2):

(In formula (2), R ³ is a hydrogen atom or a methyl group, R ⁴ is a linear or branched alkylene group having 2 to 6 carbon atoms, X is an oxygen atom or -NH-, and M ⁺ is a hydrogen ion. is a monovalent cation except for the monomer (a2) represented by the formula (3):

(In the formula (3), R ⁵ is a hydrogen atom or a methyl group, and R ⁶ is a linear or branched alkyl group having 1 to 4 carbon atoms.) and a monomer (a3) represented by the formula (4):

(In formula (4), R ⁷ is a hydrogen atom or a methyl group, R ⁸ is a hydrogen atom or a straight or branched alkyl group having 1 to 3 carbon atoms, and R ⁹ is a straight chain having 1 to 3 carbon atoms. or a branched alkyl group, and R ⁸ and R ⁹ may be the same or different. is a coalescence,
In the monomer mixture, the proportion of the monomer (a1) is 0.5 to 7% by mass, the proportion of the monomer (a2) is 5 to 35% by mass, and the monomer The ratio of (a3) is 10 to 50% by mass, the ratio of the monomer (a4) is 25 to 75% by mass,
The total mass ratio of the monomer (a2) and the monomer (a4) to the monomer (a3) [{(a2) + (a4)}/(a3)] is 0.5 or more and 10 It relates to a hydrophilizing coating composition which is:

The present invention also relates to a hydrophilic article having a hydrophilic film formed from the hydrophilic coating composition on a substrate.

Although the details of the action mechanism of the effect of the hydrophilic coating agent composition of the present invention are partly unknown, it is presumed as follows. However, the present invention need not be construed as being limited to this action mechanism.

The hydrophilic coating composition of the present invention contains an acrylic copolymer (A) and a solvent (B), and the acrylic copolymer (A) is a specific amount represented by the formula (1) A monomer (a1), a monomer (a2) represented by the formula (2), a monomer (a3) represented by the formula (3), and a monomer (a3) represented by the formula (4) containing the monomer (a4). In particular, the hydrophilic coating composition of the present invention contains a specific amount of the monomers (a1) to (a4), and in addition, the hydrophilicity of the monomer (a3), which is a hydrophobic component, is The total mass ratio [{(a2) + (a4)} / (a3)] of the monomer (a2) and the monomer (a4), which are components, is a specific ratio, so that the acrylic copolymer Since it is presumed that the balance between hydrophilicity and hydrophobicity of (A) can be optimized, the hydrophilic film formed from the hydrophilic coating composition of the present invention has good adhesion to the substrate. , and can maintain hydrophilicity.

The hydrophilic coating composition of the present invention contains an acrylic copolymer (A) and a solvent (B).

<Acrylic copolymer (A)>
The acrylic copolymer (A) of the present invention comprises a monomer (a1) represented by formula (1), a monomer (a2) represented by formula (2), and a formula (3). It is a copolymer formed from a monomer mixture containing the monomer (a3) represented by the formula (4) and the monomer (a4) represented by the formula (4).

（式（１）中、Ｒ^１は水素原子またはメチル基、Ｒ^２は水素原子または炭素数１～４の直鎖または分岐鎖のアルキル基である。） <Monomer (a1)>
The monomer (a1) of the present invention is a monomer having an N-methylol group or an N-methylol ether group represented by the following formula (1), and is converted into a copolymer by dehydration condensation reaction and dealcoholization condensation reaction. It has the function of forming a cross-linked structure in the surface and increasing the coating strength of the hydrophilized film. At least one monomer (a1) may be used, and two or more thereof may be used in combination.

(In formula (1), R ¹ is a hydrogen atom or a methyl group, and R ² is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms.)

In the above formula (1), examples of linear or branched alkyl groups having 1 to 4 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, tert-butyl group and the like. In formula (1), R ² is preferably a hydrogen atom, a methyl group, or an n-butyl group.

Examples of the compound represented by formula (1) in the monomer (a1) include N-methylol(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-propoxymethyl(meth)acrylamide, and N-butoxymethyl (meth)acrylamide. Among these, N-methylol(meth)acrylamide and N-methoxymethyl(meth)acrylamide are preferable from the viewpoint of reactivity in dehydration condensation reaction and dealcoholization condensation reaction.

（式（２）中、Ｒ^３は水素原子またはメチル基、Ｒ^４は炭素数２以上６以下の直鎖または分岐鎖のアルキレン基、Ｘは酸素原子または－ＮＨ－、Ｍ^＋は水素イオンを除く一価のカチオンである。） <Monomer (a2)>
The monomer (a2) of the present invention is a salt of a monomer having a sulfonic acid group represented by the following formula (2), and has the function of increasing the hydrophilicity of the hydrophilic membrane. At least one monomer (a2) may be used, and two or more thereof may be used in combination.

(In formula (2), R ³ is a hydrogen atom or a methyl group, R ⁴ is a linear or branched alkylene group having 2 to 6 carbon atoms, X is an oxygen atom or -NH-, and M ⁺ is a hydrogen ion. are monovalent cations except

In the above formula (2), the linear or branched alkylene group having 2 to 6 carbon atoms includes, for example, a linear ethylene group, a branched ethylene group, a linear propylene group, a branched propylene group, a linear butylene group, and a branched A butylene group, a straight-chain pentylene group, a branched pentylene group, a straight-chain hexylene group, a branched hexylene group, and the like. In the above formula (2), the monovalent cations other than hydrogen ions include, for example, lithium ion, sodium ion, potassium ion, ammonium ion, methylammonium ion, dimethylammonium ion, trimethylammonium ion, ethylammonium ion, Diethylammonium ion, triethylammonium ion, monoethanolammonium ion, diethanolammonium ion, triethanolammonium ion, dimethyloxyethylammonium ion, diethyloxyethylammonium ion, anilinium ion, α-naphthylammonium ion, benzylammonium ion, pyridinium ion , 2,6-lutidinium ion, imidazolium ion and the like. From the viewpoint of increasing the hydrophilicity of the hydrophilized film, R ⁴ is preferably a linear or branched alkylene group having 2 or more and 4 or less carbon atoms, such as a linear ethylene group, a linear propylene group, or a branched butylene group. and M ⁺ is preferably a sodium ion, a potassium ion, or an ammonium ion.

Examples of the compound represented by formula (2) in the monomer (a2) include 2-(methacryloyloxy)ethanesulfonic acid (R ³ =methyl group, R ⁴ =linear ethylene group, X = oxygen atom), 3-(methacryloyloxy)-1-propanesulfonic acid (R ³ = methyl group, R ⁴ = linear propylene group, X = oxygen atom), 2-acrylamidopropanesulfonic acid (R ³ = hydrogen atom, R ⁴ = branched propylene group, X=NH), 2-acrylamido-2-methylpropanesulfonic acid (R ³ = hydrogen atom, R ⁴ = branched butylene group, X=NH), 3-acrylamide-2,3 -Dimethylbutane-2-sulfonic acid (R ³ =hydrogen atom, R ⁴ =branched hexylene group, X=NH) and other vinyl compounds having a sulfonic acid group, and salts of the aforementioned monovalent cations. Among these, sodium 2-(methacryloyloxy)ethanesulfonate, ammonium 3-(methacryloyloxy)-1-propanesulfonate, potassium 2-acrylamidopropanesulfonate, sodium 2-acrylamido-2-methylpropanesulfonate is preferred.

（式（３）中、Ｒ^５は水素原子またはメチル基、Ｒ^６は炭素数１～４の直鎖または分岐鎖のアルキル基である。） <Monomer (a3)>
The monomer (a3) of the present invention is a (meth)acrylate-based monomer represented by the following formula (3), and has the function of enhancing the adhesion of the hydrophilic film to the substrate. At least one monomer (a3) may be used, and two or more thereof may be used in combination.

(In formula (3), R ⁵ is a hydrogen atom or a methyl group, and R ⁶ is a linear or branched alkyl group having 1 to 4 carbon atoms.)

In the above formula (3), the linear or branched alkyl group having 1 to 4 carbon atoms includes, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, Isobutyl group, tert-butyl group and the like can be mentioned, and methyl group and ethyl group are preferred.

Examples of the compound represented by the formula (3) in the monomer (a3) include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, Examples include n-butyl (meth)acrylate, isobutyl (meth)acrylate and t-butyl (meth)acrylate. Among these, methyl (meth)acrylate and ethyl (meth)acrylate are preferable from the viewpoint of increasing the hydrophilicity of the hydrophilic film.

（式（４）中、Ｒ^７は水素原子またはメチル基、Ｒ^８は水素原子または炭素数１～３の直鎖もしくは分岐鎖のアルキル基であり、Ｒ^９は炭素数１～３の直鎖または分岐鎖のアルキル基であり、Ｒ^８およびＲ^９はそれぞれ同一でもよく、異なっていてもよい。） <Monomer (a4)>
The monomer (a4) of the present invention is a (meth)acrylamide-based monomer represented by the following formula (4) and has the function of increasing the hydrophilicity and coating strength of the hydrophilic film. At least one monomer (a4) may be used, and two or more thereof may be used in combination.

(In formula (4), R ⁷ is a hydrogen atom or a methyl group, R ⁸ is a hydrogen atom or a straight or branched alkyl group having 1 to 3 carbon atoms, and R ⁹ is a straight chain having 1 to 3 carbon atoms. or a branched alkyl group, and R ⁸ and R ⁹ may be the same or different.)

In the above formula (4), the linear or branched alkyl group having 1 to 3 carbon atoms in R ⁸ includes, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a hydrogen atom, A methyl group and an ethyl group are preferred. In the above formula (4), examples of the linear or branched alkyl group having 1 to 3 carbon atoms in R ⁹ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a methyl group, Ethyl groups are preferred.

Examples of the compound represented by the formula (4) in the monomer (a4) include N-methylacrylamide, N,N-dimethyl(meth)acrylamide, N-ethyl(meth)acrylamide, N,N -diethyl (meth)acrylamide, N-normal propyl (meth)acrylamide, N-isopropyl (meth)acrylamide and the like. Among these, N,N-dimethyl(meth)acrylamide and N,N-diethyl(meth)acrylamide are preferred from the viewpoint of increasing the hydrophilicity and coating strength of the hydrophilic film.

<Monomer (a5)>
The monomer mixture contains a bifunctional (meth)acrylate monomer (a5) from the viewpoint of increasing the molecular weight of the acrylic copolymer (A) and increasing the coating strength of the hydrophilic film. You can stay. Two or more of the bifunctional (meth)acrylate monomers (a5) may be used in combination.

Examples of the monomer (a5) include polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, and ethylene oxide-modified bisphenol. A di(meth)acrylate, propylene oxide-modified bisphenol A di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, glycerin di(meth)acrylate, ethylene oxide modified glycerin di(meth)acrylate, propylene oxide modified glycerin di(meth)acrylate, ethylene glycol diglycidyl ether di(meth)acrylate, diethylene glycol diglycidyl ether di(meth)acrylate, phthalate diglycidyl ester di(meth)acrylate, Hydroxypivalic acid-modified neopentyl glycol di(meth)acrylate, epoxy resin-modified di(meth)acrylate, urethane di(meth)acrylate, ethylene oxide isocyanurate-modified di(meth)acrylate, and the like. Among these, polyethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and 1,10-decane are preferred from the viewpoint of excellent compatibility with the monomers (a1) to (a4). Diol di(meth)acrylates are preferred.

The proportion of the monomer (a1) is 0.5 to 7% by mass in the monomer mixture. The proportion of the monomer (a1) is preferably 1% by mass or more, more preferably 2% by mass or more, in the monomer mixture from the viewpoint of increasing the coating film strength. From the viewpoint of suppressing a decrease in adhesion to the material, it is preferably 5% by mass or less, more preferably 4% by mass or less, in the monomer mixture.

The proportion of the monomer (a2) is 5 to 35% by mass in the monomer mixture. The proportion of the monomer (a2) is preferably 10% by mass or more, more preferably 15% by mass or more, in the monomer mixture from the viewpoint of increasing hydrophilicity, and the coating film From the viewpoint of suppressing a decrease in strength, it is preferably 30% by mass or less, more preferably 25% by mass or less, in the monomer mixture.

The proportion of the monomer (a3) is 10 to 50% by mass in the monomer mixture. The proportion of the monomer (a3) is preferably 15% by mass or more, more preferably 20% by mass or more, from the viewpoint of improving the adhesion to the substrate, and the decrease in hydrophilicity is From the viewpoint of suppression, it is preferably 45% by mass or less, more preferably 40% by mass or less, in the monomer mixture.

The proportion of the monomer (a4) is 25-75% by mass in the monomer mixture. The proportion of the monomer (a4) is preferably 30% by mass or more, more preferably 35% by mass or more, in the monomer mixture from the viewpoint of increasing the hydrophilicity and coating strength of the hydrophilic film. is more preferably 40% by mass or more, and from the viewpoint of suppressing a decrease in hydrophilicity sustainability, it is preferably 70% by mass or less, and 65% by mass or less in the monomer mixture. It is more preferable that the content is 60% by mass or less.

When using the bifunctional (meth)acrylate monomer (a5), the proportion of the monomer (a5) is preferably 0.01 to 1% by mass in the monomer mixture. . The proportion of the monomer (a5) is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, in the monomer mixture, from the viewpoint of increasing the strength of the coating film. And, from the viewpoint of suppressing deterioration of paintability, it is preferably 0.5% by mass or less, more preferably 0.3% by mass or less in the monomer mixture.

The total ratio of the monomers (a1) to (a4), or the total ratio of the monomers (a1) to (a5), in the monomer mixture, provides good adhesion to the substrate. From the viewpoint of obtaining a hydrophilic film that has a hydrophilic property and can maintain hydrophilicity, the content is preferably 80% by mass or more, more preferably 85% by mass or more, further preferably 90% by mass or more, and 95% by mass. % or more is even more preferable.

The mass ratio [(a1)/{(a2)+(a4)}] of the monomer (a1) to the sum of the monomer (a2) and the monomer (a4) is 0.3 or less Preferably. The mass ratio of the monomer (a1) to the total of the monomer (a2) and the monomer (a4) [(a1) / {(a2) + (a4)}] is a good coating strength is preferably 0.01 or more from the viewpoint of increasing the hydrophilicity, and preferably 0.2 or less, preferably 0.15 or less, and 0.1 or less from the viewpoint of increasing hydrophilicity is more preferable.

The total mass ratio of the monomer (a2) and the monomer (a4) to the monomer (a3) [{(a2) + (a4)}/(a3)] is 0.5 or more and 10 It is below. The total mass ratio of the monomer (a2) and the monomer (a4) to the monomer (a3) [{(a2) + (a4)}/(a3)] is good for the substrate It is preferably 0.8 or more, more preferably 1 or more, and preferably 8 or less from the viewpoint of obtaining a hydrophilic film that has good adhesion and can maintain hydrophilicity.

<Other monomers>
The monomer mixture can contain other monomers. Examples of the other monomers include aromatic vinyl-based monomers such as styrene, vinyltoluene, and α-methylstyrene; (methoxy)polyethylene glycol mono(meth)acrylate, (methoxy)polypropylene glycol mono(meth) Alkoxyalkylene glycol (meth)acrylate-based monomers such as acrylate, (ethoxy)polyethylene glycol mono(meth)acrylate, (ethoxy)polypropylene glycol mono(meth)acrylate; polyethylene glycol mono(meth)acrylate, glycerin mono(meth)acrylate hydroxyl group-containing vinyl monomers such as acrylates and ε-caprolactone adducts of 2-hydroxyethyl (meth)acrylate; carboxyl group-containing monomers such as (meth)acrylic acid, crotonic acid, maleic acid, and maleic acid half esters (meth)acrylamide, diacetone (meth)acrylamide, N-(meth)acryloylpiperidine, (meth) acryloylmorpholine , N-vinyl-2-pyrrolidone, 2-vinylpyridine, etc. and nitrogen atom-containing vinyl monomers. The other monomers may be used in combination of two or more.

<Method for producing acrylic copolymer (A)>
The acrylic copolymer (A) is obtained by copolymerizing the monomer mixture. The structure of the copolymer may be a random copolymer, an alternating copolymer, a block copolymer, or a graft copolymer. Random copolymers are preferable from the viewpoint of being able to improve the effect of (1) and being able to easily prepare a hydrophilic coating agent composition. As the polymerization method for obtaining the copolymer, various known polymerization methods such as radical polymerization method, cationic polymerization method, anionic living polymerization method, and cationic living polymerization method are employed. However, the radical polymerization method is preferable from the standpoint of performance that spans many meanings. As the radical polymerization method, a conventional bulk polymerization method, suspension polymerization method, solution polymerization method, emulsion polymerization method, or the like is employed. Legal is preferred.

Examples of the polymerization solvent used in the solution polymerization method include alcohol solvents such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, s-butanol, t-butanol, and diacetone alcohol; ethylene glycol monomethyl; Alcohol ether solvents such as ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, 3-methoxy-1-butanol, 3-methoxy-3-methyl-1-butanol; acetone, methyl ethyl ketone, methyl Ketone solvents such as isobutyl ketone and cyclohexanone; Ether solvents such as tetrahydrofuran and dioxane; Ester solvents such as methyl acetate, ethyl acetate, n-butyl acetate, isobutyl acetate, t-butyl acetate, methyl lactate and ethyl lactate; benzene , aromatic solvents such as toluene and xylene, amide solvents such as formamide and dimethylformamide, and water. At least one of the polymerization solvents may be used, and two or more of them may be used in combination. In addition, the said polymerization solvent can be used as a solvent (B) mentioned later.

In the solution polymerization method, in the total 100 parts by mass of the monomer mixture and the polymerization solvent used for the polymerization reaction, the monomer mixture is 60 parts by mass or less from the viewpoint of facilitating industrial production by suppressing polymerization heat generation. preferably 50 parts by mass or less.

Commonly used organic peroxides, azo compounds, and the like can be used as the initiator in the radical polymerization method. Examples of organic peroxides include benzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, t-butylperoxy-2-hexanoate, t-butylperoxypivalate, and t-hexylperoxide. oxypivalate, t-butylperoxyneodecanate, t-hexylperoxyneodecanate and the like. Examples of azo compounds include 2,2'-azobisisobutyronitrile and 2,2'-azobis-2-methylbutyronitrile. The amount of the initiator used is preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the monomer mixture. It is preferable to carry out the polymerization while dropping the radical polymerization initiator into the reaction vessel, since this makes it easier to control the heat generated by the polymerization. The temperature at which the polymerization reaction is carried out is appropriately changed depending on the type of the radical polymerization initiator used, but is preferably 30 to 150°C, more preferably 40 to 100°C for industrial production.

<Solvent (B)>
The hydrophilic coating composition of the present invention contains a solvent (B) in order to improve viscosity, coatability, and smoothness of the hydrophilic film. The solvent (B) is capable of dissolving or dispersing components such as the acrylic copolymer (A), and is not particularly limited as long as it is a solvent that volatilizes at the drying temperature. At least one of the solvents (B) may be used, and two or more of them may be used in combination.

Examples of the solvent (B) include water, alcohol solvents, ketone solvents, amide solvents, ether solvents and the like. Examples of the alcohol solvent include methanol, isopropyl alcohol, n-butanol, diacetone alcohol, 2-methoxyethanol (methyl cellosolve), 2-ethoxyethanol (ethyl cellosolve), 2-butoxyethanol (butyl cellosolve), tertiary amyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, 3-methoxy-1-butanol, 3-methoxy-3-methyl-1-butanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether , diethylene glycol mono-normal propyl ether, diethylene glycol mono- isopropyl ether and the like. Examples of the ketone solvent include methyl ethyl ketone, methyl isobutyl ketone, acetone and cyclohexanone. Examples of the amide solvent include dimethylformamide and dimethylacetamide. Examples of the ether solvent include diethyl ether, methoxytoluene, 1,2-dimethoxyethane, 1,2-dibutoxyethane, 1,1-dimethoxymethane, 1,1-dimethoxyethane, 1,4-dioxane, tetrahydrofuran and the like. Among these, it is preferable that the solvent (B) contains water.

When water is used as the solvent (B), the proportion of water in the solvent (B) is preferably 50% by mass or more, and 60% by mass or more, from the viewpoint of increasing the safety of the coating liquid. is more preferred.

A curing catalyst may be used in the hydrophilic coating composition of the present invention from the viewpoint of accelerating the dehydration condensation reaction and the dealcoholization condensation reaction of the monomer represented by the formula (1). Examples of the curing catalyst include organic sulfonic acids such as p-toluenesulfonic acid and acidic phosphates such as monoalkyl phosphates and dialkyl phosphates. The amount of the curing catalyst used is about 0.1 to 10 parts by mass with respect to 100 parts by mass of the acrylic copolymer (A).

<Other ingredients>
The hydrophilic coating composition of the present invention may optionally contain other components such as surfactants such as nonionic surfactants, cationic surfactants, anionic surfactants and betaine surfactants; silicone leveling agents; leveling agents such as , fluorine-based leveling agents, and acetylene-based leveling agents; and various conventional additives such as antioxidants, ultraviolet absorbers, and light stabilizers. The amount of the other components added can be blended in a conventional amount for each additive, but usually about 10 parts by mass or less per 100 parts by mass of the acrylic copolymer (A). be.

<Production of hydrophilic coating composition>
Hydrophilic coating composition, for example, for the purpose of adjusting the solid content and viscosity of the acrylic copolymer (A) suitable for coating, by adding the solvent (B) to dissolve, disperse or dilute. can be manufactured by Depending on the coating method, the solid content and viscosity suitable for coating differ, but in the case of the dip coating method, the acrylic copolymer (A) is preferably 1% by mass or more, and 3% by mass in the hydrophilic coating composition. The above is more preferable, 30% by mass or less is preferable, and 20% by mass or less is even more preferable.

<Hydrophilic article>
The hydrophilic article of the present invention has a hydrophilic film formed on the surface of the substrate by applying the hydrophilic coating agent composition to a substrate by a coating method that is used in ordinary paints, followed by heating and curing. is. For the purpose of volatilizing and drying the solvent contained in the hydrophilic coating composition immediately after coating, a drying step may be provided before the heat curing step.

The substrate may be of any type, and examples thereof include glass, silicon wafer, metal, plastic films and sheets, and three-dimensional molded articles, and the shape of the substrate is not limited. . Examples of the plastic include polymethyl methacrylate resin, polycarbonate resin, polystyrene resin, acrylonitrile-styrene copolymer resin, polyvinyl chloride resin, acetate resin, ABS resin, polyester resin, and polyamide resin.

When coating the base material, it is preferable to remove adhering foreign substances from the base material surface before coating for the purpose of increasing the wettability of the hydrophilic coating composition to the base material and preventing repelling. Examples of such methods include dust removal using high-pressure air or ionized air; ultrasonic cleaning using an aqueous detergent solution or alcohol solvent; wiping using an alcohol solvent or the like; cleaning using ultraviolet rays or ozone. Examples of coating methods include gravure, roll coating, dip coating, brush coating, spray coating, bar coating, knife coating, die coating, and spin coating.

The heat curing temperature is usually 60 to 150° C. for 5 to 60 minutes, preferably 70 to 130° C. for 10 to 40 minutes. Moreover, the drying is usually performed at a temperature of 20 to 50° C. for 0.5 to 5 minutes. However, when the base material is plastic, it is preferable to set the curing temperature below the heat distortion temperature of the plastic.

The film thickness of the hydrophilic film is preferably 0.5 to 20 μm, more preferably 1 to 10 μm, in order to obtain good hydrophilicity and coating appearance. If the film thickness is less than 0.5 µm, the hydrophilicity of the coating film tends to decrease, and if it exceeds 20 µm, the coating film appearance tends to be poor.

The hydrophilic article is preferably used for goggles, windows, mirrors and the like. Examples of specific goggles include swimming goggles and diving goggles.

EXAMPLES The present invention will be described in more detail with reference to Examples below, but the present invention is not limited to these Examples.

<Example 1>
<Synthesis of acrylic copolymer (A)>
A reaction vessel equipped with a stirrer, a nitrogen inlet tube and a cooling tube was charged with 260 parts by mass of propylene glycol monomethyl ether as the solvent (B), 2 parts by mass of N-butoxymethylacrylamide as the monomer (a1), and the monomer ( 30 parts by mass of sodium 2-(methacryloyloxy)ethanesulfonate as a2), 27.9 parts by mass of methyl acrylate as monomer (a3), 40 parts by mass of N,N-dimethylacrylamide as monomer (a4), And 0.1 part by mass of polyethylene glycol-dimethacrylate (trade name: Blenmer PDE-200, manufactured by NOF Corporation) as a monomer (a5) was charged and heated to 55° C. while blowing nitrogen gas. 0.5 parts by mass of t-hexyl peroxyneodecanate diluted with hydrocarbon (trade name: Perhexyl ND, manufactured by NOF Corporation) as a radical polymerization initiator, and propylene glycol monomethyl as a solvent (B). A solution dissolved in 40 parts by mass of ether was added dropwise over 3 hours. After further conducting polymerization for 5 hours, the temperature was raised to 70° C., and polymerization was carried out at that temperature for 1 hour to obtain a solution of the acrylic copolymer (A) of Example 1 having a copolymer concentration of 25% by mass. Obtained.

<Preparation of hydrophilic coating composition>
To the solution of the acrylic copolymer (A) of Example 1 obtained above, 650 parts by mass of propylene glycol monomethyl ether as the solvent (B) and 950 parts by mass of water are added, and 1 mass of p-toluenesulfonic acid is added as a curing catalyst. and 1 part by mass of polyether-modified polydimethylsiloxane (trade name: KF-351A, manufactured by Shin-Etsu Chemical Co., Ltd.) as a leveling agent to obtain a hydrophilic coating composition.

<Preparation of hydrophilic article>
The hydrophilic coating composition obtained above was applied to a polycarbonate substrate (5 cm×5 cm×1 mm, trade name: Iupilon Sheet NF-2000, manufactured by MGC Filsheet Co., Ltd.) using a bar coater. Then, the polycarbonate substrate was heat-cured at 120° C. for 30 minutes to prepare a hydrophilized article (test piece) having a hydrophilic film with a thickness of about 3 μm on the polycarbonate substrate.

Using the test pieces obtained above, the following evaluations (1) to (4) were performed. Table 1 shows the results.

<(1) Evaluation of Adhesion>
The hydrophilized film of the test piece obtained above was cut vertically and horizontally at intervals of 1 mm to form 100 squares in a grid pattern, and the cellophane tape was completely adhered to the grid. The cellophane tape was pulled off momentarily, and the state of the grid pattern was visually confirmed and evaluated according to the following three grades. If the evaluation is ◯ or higher, there is no practical problem, and if it is ⊚, it is more preferable.
A: Peeling is not observed at all.
○: Peeling is slightly observed.
x: Peeling is clearly observed.

<(2) Evaluation of hydrophilicity>
After immersing the test piece obtained above in an aqueous sodium hypochlorite solution adjusted to have a chlorine concentration of 1 ppm at 30 ° C. for 1 hour, place the test piece vertically for 1 minute. It was evaluated visually. Judgment criteria are as follows. If the evaluation is ◯ or higher, there is no practical problem, and if it is ⊚, it is more preferable.
A: The area of the portion wet with water is 80% or more.
◯: The area of the portion wet with water is 60% or more and less than 80%.
x: The area of the portion wet with water is less than 60%, and repelling of water is observed. Alternatively, the coating film is dissolved.

<(3) Evaluation of hydrophilicity sustainability>
The test piece obtained above was immersed in an aqueous sodium hypochlorite solution adjusted to have a chlorine concentration of 1 ppm at 30° C. for 1 hour, and then dried. This operation was performed 9 times. After that, after being immersed in 1 ppm chlorine water at 30° C. for 1 hour, the test piece was vertically placed for 1 minute, and then the wetted area was visually evaluated. Judgment criteria are as follows. If the evaluation is ◯ or higher, there is no practical problem, and if it is ⊚, it is more preferable.
A: The area of the portion wet with water is 80% or more.
◯: The area of the portion wet with water is 60% or more and less than 80%.
x: The area of the portion wet with water is less than 60%, and repelling of water is observed. Alternatively, the coating film is dissolved.

<(4) Evaluation of coating film strength>
The surface of the test piece obtained above was rubbed with the pad of a finger for 10 seconds while being wetted with running water, and then the appearance of the coating film was visually evaluated. Judgment criteria are as follows. If the evaluation is ◯ or higher, there is no practical problem, and if it is ⊚, it is more preferable.
(double-circle): A crack is not seen on the surface.
◯: Scratches are slightly observed on the surface.
x: Scratches are clearly seen on the surface.

<Examples 2 to 15 and Comparative Examples 1 to 9>
<Synthesis of Acrylic Copolymer (A), Preparation of Hydrophilized Coating Composition, and Production of Hydrophilized Article>
In each example and comparative example, acrylic copolymer (A) was synthesized in the same manner as in Example 1, except that the type and blending amount of each raw material was changed as shown in Tables 1 and 2. After that, a hydrophilized coating agent composition was prepared, and a hydrophilized article (test piece) having a hydrophilized film on a polycarbonate substrate was produced.

Adhesion, hydrophilicity, hydrophilicity persistence, and coating film strength were evaluated by the evaluation methods described above using the test pieces obtained above. The results are shown in Tables 1-2.

In Tables 1 and 2, Blemmer PDE-200 is polyethylene glycol dimethacrylate (trade name: Blenmer PDE-200, manufactured by NOF Corporation); KF-351A is polyether-modified polydimethylsiloxane (trade name: KF- 351A, manufactured by Shin-Etsu Chemical Co., Ltd.);

It was confirmed that the hydrophilic films formed from the hydrophilizing agent compositions of Examples 1 to 15 exhibited hydrophilicity and hydrophilicity persistence, and also exhibited adhesion and coating film strength. In particular, Examples 2 to 4, 7 to 9 and 12 to 14 gave excellent results in terms of hydrophilicity, hydrophilicity persistence, adhesion and coating film strength.

On the other hand, in Comparative Example 1, since the monomer (a1) in the acrylic copolymer (A) was not used, the adhesiveness, the durability of hydrophilicity, and the strength of the coating film were lowered. In addition, in Comparative Example 2, since the ratio of the monomer (a1) was large, deterioration in adhesion, hydrophilicity, and durability of hydrophilicity was observed.

In Comparative Example 3, since the monomer (a2) in the acrylic copolymer (A) was not used, a decrease in hydrophilicity and hydrophilicity persistence was observed. In addition, in Comparative Example 4, since the ratio of the monomer (a2) was large, a decrease in the durability of hydrophilicity was observed.

In Comparative Example 5, since the monomer (a3) in the acrylic copolymer (A) was not used, a decrease in adhesion was observed. Moreover, in Comparative Example 6, since the ratio of the monomer (a3) was large, a decrease in hydrophilicity and durability of hydrophilicity was observed.

In Comparative Example 7, since the monomer (a4) in the acrylic copolymer (A) was not used, a decrease in hydrophilicity and hydrophilicity persistence was observed. In addition, in Comparative Example 8, since the ratio of the monomer (a4) was large, deterioration in adhesiveness, hydrophilicity, and durability of hydrophilicity was observed.

Comparative Example 9 is an acrylic copolymer disclosed in the example of Patent Document 4, and has a composition in which the monomer (a1) and the monomer (a3) are large and the monomer (a4) is small. Therefore, a decrease in hydrophilicity and durability of hydrophilicity was observed.

Claims (4)

A hydrophilic coating composition containing an acrylic copolymer (A) and a solvent (B),
The acrylic copolymer (A) has the formula (1):

(In formula (1), R ¹ is a hydrogen atom or a methyl group, and R ² is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms.) and equation (2):

(In formula (2), R ³ is a hydrogen atom or a methyl group, R ⁴ is a linear or branched alkylene group having 2 to 6 carbon atoms, X is an oxygen atom or -NH-, and M ⁺ is a hydrogen ion. is a monovalent cation except for the monomer (a2) represented by the formula (3):

(In the formula (3), R ⁵ is a hydrogen atom or a methyl group, and R ⁶ is a linear or branched alkyl group having 1 to 4 carbon atoms.) and a monomer (a3) represented by the formula (4):

(In formula (4), R ⁷ is a hydrogen atom or a methyl group, R ⁸ is a hydrogen atom or a straight or branched alkyl group having 1 to 3 carbon atoms, and R ⁹ is a straight chain having 1 to 3 carbon atoms. or a branched alkyl group, and R ⁸ and R ⁹ may be the same or different. is a coalescence,
In the monomer mixture, the proportion of the monomer (a1) is 0.5 to 7% by mass, the proportion of the monomer (a2) is 5 to 35% by mass, and the monomer The ratio of (a3) is 10 to 50% by mass, the ratio of the monomer (a4) is 25 to 75% by mass,
The total mass ratio of the monomer (a2) and the monomer (a4) to the monomer (a3) [{(a2) + (a4)}/(a3)] is 0.5 or more and 10 A hydrophilic coating composition characterized by: The monomer mixture further contains a bifunctional (meth)acrylate monomer (a5), and the monomer (a5) in the monomer mixture is 0.01 to 1% by mass. The hydrophilic coating composition according to claim 1, characterized in that: 3. The hydrophilizing coating composition according to claim 1, wherein the solvent (B) contains water, and the proportion of the water in the solvent (B) is 50% by mass or more. A hydrophilized article comprising a base material and a hydrophilized film formed from the hydrophilic coating composition according to any one of claims 1 to 3 on the substrate.