JP2023162847A - Method for producing anti-fogging member, anti-fogging member, and method for preventing warping in anti-fogging member - Google Patents

Abstract

To provide a method for producing an anti-fogging member that is superior in both water resistance and water absorbency; an anti-fogging member; and a method for preventing warping in an anti-fogging member.SOLUTION: A method for producing an anti-fogging member includes the steps of: disposing a coating composition containing a polyvinyl alcohol resin, an aqueous medium and a polymerizable component on a substrate to form an uncrosslinked layer; and crosslinking the uncrosslinked layer to from a coating layer, where, the uncrosslinked layer has a moisture content that is 10 mass% or more and 95 mass% or less based on the total mass of the uncrosslinked layer. The polymerizable component is at least one compound selected from the group consisting of a crosslinker and a polymerization initiator. The coating layer has a thickness of 3 μm or more and less than 20 μm when controlled to have a moisture content of less than 10 mass%.SELECTED DRAWING: None

Description

The present invention relates to a method for manufacturing an anti-fog member, an anti-fog member, and a method for suppressing warping of the anti-fog member.

Polyvinyl alcohol resin has water absorption and hydrophilic properties. As a result, when a coating layer of polyvinyl alcohol resin is formed on the surface of a substrate such as glass, metal, or plastic film, the coating layer of polyvinyl alcohol resin absorbs minute water droplets that occur on the surface of the substrate when the temperature drops below the dew point. This can prevent the formation of cloudiness on the substrate. Utilizing this property, polyvinyl alcohol resin is used as an antifogging agent to ensure visibility.

Such a coating layer is required not only to have excellent antifogging performance, but also to have excellent water resistance because it comes into contact with water. However, coating layers using polyvinyl alcohol resin inherently have poor water resistance.

In order to make polyvinyl alcohol resin water resistant, there are methods of introducing an acetoacetate group (Patent Document 1) or a methacryloyl group (Patent Document 2) into the side chain and crosslinking it in a water-containing state to make it water resistant, and polyvinyl alcohol coating film. A method of imparting hot water resistance by irradiating electron beams while the material is in a swollen state is disclosed (Patent Document 3).

Special Publication No. 6-53817 International Publication No. 2020/218459 Japanese Patent Application Publication No. 6-143507

However, the water resistance method described in Patent Document 1 has a problem in that the water absorbency (i.e., antifogging property) of the coating film (coating layer) decreases as the water resistance improves. Further, the antifogging member described in Patent Document 2 becomes foggy when the coating layer reaches a saturated water absorption state. As a result, in order to maintain the antifogging effect over a long period of time, it is necessary to thicken the coating layer and increase the saturated water absorption amount. However, when the coating layer is thickened and applied to a hard base material, the hardness of the antifogging member decreases, making it difficult to apply it to the outermost layer, which is expected to be used as a coating with an antifogging effect. Furthermore, when the coating layer is made thinner and applied to a soft substrate in order to suppress a decrease in hardness, residual stress increases and the antifogging member warps, making it similarly difficult to apply it to the outermost layer. Furthermore, although the method for making a polyvinyl alcohol paint film water resistant described in Patent Document 3 adjusts the water content when crosslinking the paint film, there is no mention of improving the water absorption of the paint film (coating layer). do not have.

The present invention has been made to solve the above problems, and includes a method for manufacturing an anti-fog member that is excellent in both water resistance and water absorption, an anti-fog member, and occurrence of warpage in the anti-fog member. The purpose is to provide a method to suppress this.

［式（Ｉ）中、Ｒ^１、Ｒ^２およびＲ^３は、それぞれ独立して水素原子、メチル基、カルボキシル基、またはカルボキシメチル基であり、Ｘは酸素原子または－Ｎ（Ｒ^４）－であり、Ｒ^４は水素原子または炭素数１～３の炭化水素基であり、＊は該エチレン性不飽和基の結合手である］
［５］前記変性ポリビニルアルコール系樹脂が、以下の式（ＩＩ）または（ＩＩＩ）で表される構造単位を含むポリビニルアルコール系樹脂である、［１］～［４］のいずれかに記載の製造方法。

［式（ＩＩ）中、Ｒ^１、Ｒ^２およびＲ^３は、それぞれ独立して水素原子、メチル基、カルボキシル基、またはカルボキシメチル基であり、Ｘは酸素原子または－Ｎ（Ｒ^４）－であり、Ｒ^４は水素原子または炭素数１～３の炭化水素基であり、Ｙは置換基を有していてもよい炭素数１～１０の２価の炭化水素基を表し、＊は該変性ポリビニルアルコール系樹脂における構造単位の結合手である］、

［式（ＩＩＩ）中、Ｒ^１、Ｒ^２およびＲ^３は、それぞれ独立して水素原子、メチル基、カルボキシル基、またはカルボキシメチル基であり、＊は該変性ポリビニルアルコール系樹脂における構造単位の結合手である］
［６］前記基材が、樹脂、ガラスおよび金属からなる群から選択される少なくとも１種の材料で構成されている、［１］～［５］のいずれかに記載の製造方法。
［７］前記架橋工程が前記未架橋層にエネルギーを付与することによって行われ、
該エネルギーが、活性エネルギー線および熱からなる群から選択される少なくとも１種である、［１］～［６］のいずれかに記載の製造方法。
［８］防曇性部材であって、
基材とコーティング層とを含み、
該コーティング層がポリビニルアルコール系樹脂と水性媒体と重合性成分とを含むコーティング組成物から得られるものであり、
該コーティング層が１０質量％未満の含水率に調整した場合において３μｍ以上２０μｍ未満の厚みを有し、かつ０．１ＭＰａ～１０ＭＰａの残留応力を有する、防曇性部材。
［９］防曇性部材の反りの発生を抑制するための方法であって、
ポリビニルアルコール系樹脂と水性媒体と重合性成分とを含むコーティング組成物を基材上に配置して未架橋層を形成する工程、および
該未架橋層を架橋して、該基材上にコーティング層が配置された該防曇性部材を得る工程、
を含み、
該未架橋層の含水率が、該未架橋層の全体質量に対して１０質量％以上９０質量％以下であり、
該重合性成分が、架橋剤および重合開始剤からなる群から選択される少なくとも１種の化合物であり、
該コーティング層が１０質量％未満の含水率に調整した場合において３μｍ以上２０μｍ未満の厚みを有する、方法。 The present invention includes the following inventions.
[1] A method for manufacturing an anti-fog member, comprising:
a step of disposing a coating composition containing a polyvinyl alcohol resin, an aqueous medium, and a polymerizable component on a substrate to form an uncrosslinked layer; and a step of crosslinking the uncrosslinked layer to obtain a coating layer.
including;
The moisture content of the uncrosslinked layer is 10% by mass or more and 95% by mass or less based on the total mass of the uncrosslinked layer,
The polymerizable component is at least one compound selected from the group consisting of a crosslinking agent and a polymerization initiator,
A manufacturing method in which the coating layer has a thickness of 3 μm or more and less than 20 μm when the water content is adjusted to less than 10% by mass.
[2] The manufacturing method according to [1], wherein the polyvinyl alcohol resin is a modified polyvinyl alcohol resin.
[3] The manufacturing method according to [1] or [2], wherein the polyvinyl alcohol resin is a modified polyvinyl alcohol resin having an ethylenically unsaturated group in its side chain.
[4] The production method according to any one of [1] to [3], wherein the ethylenically unsaturated group includes a partial structure represented by the following formula (I).

[In formula (I), R ¹ , R ² and R ³ are each independently a hydrogen atom, a methyl group, a carboxyl group, or a carboxymethyl group, and X is an oxygen atom or -N(R ⁴ )- , R ⁴ is a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and * is a bond of the ethylenically unsaturated group]
[5] The production according to any one of [1] to [4], wherein the modified polyvinyl alcohol resin is a polyvinyl alcohol resin containing a structural unit represented by the following formula (II) or (III). Method.

[In formula (II), R ¹ , R ² and R ³ are each independently a hydrogen atom, a methyl group, a carboxyl group, or a carboxymethyl group, and X is an oxygen atom or -N(R ⁴ )- , R ⁴ is a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, Y represents a divalent hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and * indicates the modified It is a bond of a structural unit in polyvinyl alcohol resin],

[In formula (III), R ¹ , R ² and R ³ are each independently a hydrogen atom, a methyl group, a carboxyl group, or a carboxymethyl group, and * represents a bond between structural units in the modified polyvinyl alcohol resin. [It is a hand]
[6] The manufacturing method according to any one of [1] to [5], wherein the base material is made of at least one material selected from the group consisting of resin, glass, and metal.
[7] The crosslinking step is performed by applying energy to the uncrosslinked layer,
The manufacturing method according to any one of [1] to [6], wherein the energy is at least one selected from the group consisting of active energy rays and heat.
[8] An anti-fog member,
including a base material and a coating layer,
The coating layer is obtained from a coating composition containing a polyvinyl alcohol resin, an aqueous medium, and a polymerizable component,
An antifogging member, wherein the coating layer has a thickness of 3 μm or more and less than 20 μm when the moisture content is adjusted to less than 10% by mass, and has a residual stress of 0.1 MPa to 10 MPa.
[9] A method for suppressing the occurrence of warping of an anti-fog member, comprising:
A step of disposing a coating composition containing a polyvinyl alcohol resin, an aqueous medium, and a polymerizable component on a substrate to form an uncrosslinked layer, and crosslinking the uncrosslinked layer to form a coating layer on the substrate. a step of obtaining the antifogging member in which is arranged;
including;
The moisture content of the uncrosslinked layer is 10% by mass or more and 90% by mass or less based on the total mass of the uncrosslinked layer,
The polymerizable component is at least one compound selected from the group consisting of a crosslinking agent and a polymerization initiator,
A method in which the coating layer has a thickness of 3 μm or more and less than 20 μm when the water content is adjusted to less than 10% by mass.

According to the present invention, it is possible to provide an antifogging member that has excellent antifogging performance, appropriate hardness, and low residual stress. For example, the coating layer constituting the antifogging member can suppress a decrease in hardness when provided on a hard base material, and can suppress warping of the base material when provided on a soft base material. Thereby, an excellent anti-fog member can be manufactured regardless of whether the base material is hard or soft.

Although the details of the effects of the present invention are unknown, crosslinking progresses to a high degree due to the improvement in reactivity caused by the increased mobility of the polyvinyl alcohol resin due to the aqueous medium contained in the coating layer, resulting in high water resistance. It is presumed that the water absorbency of the coating layer is improved because the resin is cross-linked in a swollen state and the structure is fixed with the gaps between the polymer chains widened. As a result, it is presumed that the thickening of the coating layer for developing antifogging properties can be suppressed, leading to a decrease in hardness when applied to the hard base material, and making it possible to obtain an antifogging member with fewer defects. be done.

A photograph for illustrating an example of a cloudy state on the surface of a sample when antifogging properties were evaluated using the samples (soda glass substrate with coating layer) prepared in Examples and Comparative Examples, (a) is a photograph for explaining an example of a state in which there is no clouding on the sample and the letters on the label behind it can be seen; (b) is a photograph showing an example in which cloudyness has occurred on the sample and the letters on the label behind the sample are visible. This photograph is for illustrating an example of a state in which it is difficult to visually recognize.

(Method for manufacturing anti-fog member)
In the method for manufacturing an antifogging member of the present invention, first, a coating composition containing a polyvinyl alcohol resin, an aqueous medium, and a polymerizable component is placed on a substrate to form an uncrosslinked layer.

(Polyvinyl alcohol resin)
The polyvinyl alcohol resin used in the present invention is a polymer containing vinyl alcohol (CH ₂ ═CHOH) or a derivative thereof as at least one monomer constituent unit, and includes, for example, polyvinyl alcohol resin and modified polyvinyl alcohol resin, and combinations thereof.

Examples of the modified polyvinyl alcohol resin include polymers having various functional groups in side chains and/or containing unsaturated bonds (for example, containing them in the form of unsaturated groups). Examples of the functional group include a carboxy group, a carbonyl group, a formyl group, a cyano group, a hydroxy group, an amino group, an alkoxy group, an ether group, a halogen atom, and combinations thereof. Examples of unsaturated bonds include carbon-carbon double bonds (also referred to as ethylenically unsaturated bonds or ethylenically unsaturated groups) and carbon-carbon triple bonds, and combinations thereof.

The polyvinyl alcohol resin used in the present invention is preferably a modified polyvinyl alcohol resin having an ethylenically unsaturated group in the side chain because it can provide an antifogging member with excellent water resistance and water absorption. preferable.

The structure of the ethylenically unsaturated group that the modified polyvinyl alcohol-based resin has in the side chain is not particularly limited, and examples thereof include unsaturated groups having radical polymerizability. A cured product can be obtained from a crosslinkable composition by utilizing the excellent crosslinking reactivity based on the ethylenically unsaturated group of the modified polyvinyl alcohol resin. In particular, the ethylenically unsaturated group preferably includes a partial structure represented by the following formula (I).

（式（Ｉ）中、Ｒ^１、Ｒ^２およびＲ^３は、それぞれ独立して水素原子、メチル基、カルボキシル基、またはカルボキシメチル基であり、Ｘは酸素原子または－Ｎ（Ｒ^４）－であり、Ｒ^４は水素原子または炭素数１～３の炭化水素基であり、＊は該エチレン性不飽和基の結合手である）

(In formula (I), R ¹ , R ² and R ³ are each independently a hydrogen atom, a methyl group, a carboxyl group, or a carboxymethyl group, and X is an oxygen atom or -N(R ⁴ )-) (R ⁴ is a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and * is a bond of the ethylenically unsaturated group)

In the above formula (I), R 1 and R 2 are preferably hydrogen atoms because they have good crosslinking reactivity, and R ¹ and R ² are preferably hydrogen atoms because the solution stability of the coating composition is good. ³ is preferably a methyl group. In addition, in the above formula (I), when X is -N(R ⁴ )-, the hydrocarbon group having 1 to 3 carbon atoms that can constitute R ⁴ is, for example, a saturated hydrocarbon group having 1 to 3 carbon atoms. Examples include groups. Specifically, R ⁴ is preferably an alkyl group having 1 to 3 carbon atoms. Examples of the alkyl group having 1 to 3 carbon atoms include methyl group, ethyl group, n-propyl group, and isopropyl group. Note that in the above formula (I), X is preferably an oxygen atom because of its excellent reactivity.

The modified polyvinyl alcohol resin used in the present invention preferably contains a structural unit represented by the following formula (II) or (III).

（式（ＩＩ）中、Ｒ^１、Ｒ^２およびＲ^３は、それぞれ独立して水素原子、メチル基、カルボキシル基、またはカルボキシメチル基であり、Ｘは酸素原子または－Ｎ（Ｒ^４）－であり、Ｒ^４は水素原子または炭素数１～３の炭化水素基であり、Ｙは置換基を有していてもよい炭素数１～１０の２価の炭化水素基を表し、＊は該変性ポリビニルアルコール系樹脂における構造単位の結合手である）

(In formula (II), R ¹ , R ² and R ³ are each independently a hydrogen atom, a methyl group, a carboxyl group, or a carboxymethyl group, and X is an oxygen atom or -N(R ⁴ )-) , R ⁴ is a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, Y represents a divalent hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and * indicates the modified (It is a bond of the structural unit in polyvinyl alcohol resin)

（式（ＩＩＩ）中、Ｒ^１、Ｒ^２およびＲ^３は、それぞれ独立して水素原子、メチル基、カルボキシル基、またはカルボキシメチル基であり、＊は該変性ポリビニルアルコール系樹脂における構造単位の結合手である）

(In formula (III), R ¹ , R ² and R ³ are each independently a hydrogen atom, a methyl group, a carboxyl group, or a carboxymethyl group, and * is a bond between structural units in the modified polyvinyl alcohol resin. hand)

In the above formula (II) or (III), R ¹ and R ² are preferably hydrogen atoms because of good crosslinking reactivity, and because the solution stability of the coating composition is good. For this reason, R ³ is preferably a methyl group.

In addition, in the above formula (II), when X is -N(R ⁴ )-, the hydrocarbon group having 1 to 3 carbon atoms that can constitute R ⁴ is, for example, a saturated hydrocarbon group having 1 to 3 carbon atoms. Examples include groups. Specifically, R ⁴ is preferably an alkyl group having 1 to 3 carbon atoms. Examples of the alkyl group having 1 to 3 carbon atoms include methyl group, ethyl group, n-propyl group, and isopropyl group. Note that in the above formula (II), X is preferably an oxygen atom because of its excellent reactivity.

Furthermore, in the above formula (II), examples of the divalent hydrocarbon group having 1 to 10 carbon atoms that can constitute Y include alkylene groups having 1 to 10 carbon atoms and cycloalkylene groups having 1 to 10 carbon atoms. . Examples of the alkylene group having 1 to 10 carbon atoms include methylene group, ethylene group, propylene group, butylene group, pentylene group, hexylene group, heptylene group, octylene group, nonylene group, decylene group, and the like. Examples of the cycloalkylene group having 1 to 10 carbon atoms include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, and a cyclohexylene group. These alkylene groups and cycloalkylene groups may have an alkyl group such as a methyl group or an ethyl group as a branched structure. Further, the divalent hydrocarbon group having 1 to 10 carbon atoms that may constitute Y may be substituted with a predetermined substituent. Examples of such substituents include hydroxyl groups; amino groups; alkoxy groups such as methoxy, ethoxy, and propoxy groups; and acyl groups such as acetyl and propionyl groups. , carbonyl bond, ether bond, ester bond, amide bond, etc. Y may also form an acetal structure together with a part of the main chain of the modified polyvinyl alcohol resin.

The polyvinyl alcohol resin used in the present invention particularly has a structural unit represented by formula (III) among modified polyvinyl alcohol resins containing a structural unit represented by formula (II) or (III) above. Preferably, it is a modified polyvinyl alcohol resin.

In addition, as more specific examples of the structural unit containing the partial structure represented by the above formula (I) and the structural units represented by the above formulas (II) and (III), the structural units shown below are Can be mentioned.

（式中、＊は結合手である）。

(In the formula, * is a bond).

In the above formulas (IV-1) to (IV-6), formulas (IV-1) to (IV-3) are specific examples of the above formula (III), and the above formulas (IV-5) and ( IV-6) is a specific example of the above formula (II). The above formula (IV-4) does not belong to the above formulas (II) and (III), but is a specific example containing a partial structure represented by the formula (I).

The lower limit of the content of structural units having an ethylenically unsaturated group (for example, structural units containing a partial structure represented by formula (I)) with respect to all structural units of the vinyl alcohol resin used in the present invention is particularly limited. However, it is preferably 0.2 mol% or more, more preferably 0.3 mol% or more, and even more preferably 0.4 mol% or more, assuming the total structural units of the vinyl alcohol resin as 100 mol%. be. Further, the upper limit of the content of the structural unit having an ethylenically unsaturated group (for example, the structural unit containing the partial structure represented by formula (I)) is not particularly limited, but the total structural unit of the vinyl alcohol resin is 100 mol. %, preferably 5 mol% or less, more preferably 3 mol% or less, and even more preferably 2 mol% or less. Since the content of the structural unit having an ethylenically unsaturated group is within the range consisting of the lower and upper limits, the coating layer obtained by this manufacturing method maintains excellent water resistance and water absorption. It is also possible to improve the water resistance of the antifogging member. Furthermore, the vinyl alcohol resin may have a structural unit having two or more types of ethylenically unsaturated groups in all its structural units. For example, in the case of having two or more types of ethylenically unsaturated groups, the total content of structural units having two or more types of ethylenically unsaturated groups may be within the range consisting of the above lower limit and upper limit. preferable. Note that the term "structural unit" in this specification refers to a repeating unit that constitutes a polymer. For example, the below-mentioned "vinyl alcohol unit" and "vinyl ester unit" are also included as examples of the "structural unit."

The lower limit of vinyl alcohol units relative to the total structural units of the vinyl alcohol resin used in the present invention is not particularly limited, but it is preferably 60 mol% or more, assuming the total structural units of the vinyl alcohol resin to be 100 mol%, The content is more preferably 70 mol% or more, further preferably 80 mol% or more, particularly preferably 85 mol% or more. Further, the upper limit of the content of the vinyl alcohol unit is not particularly limited, but it is preferably 99.95 mol% or less, more preferably 99.9 mol%, assuming that the total structural units of the vinyl alcohol resin are 100 mol%. or less, more preferably 99.5 mol% or less, particularly preferably 99.0 mol%. By keeping the content of vinyl alcohol units within the range consisting of these lower and upper limits, the coating layer obtained by this manufacturing method can continuously provide excellent water resistance and water absorption, and has an anti-fog property. The water resistance of the elastic member can also be improved.

The vinyl alcohol unit can be derived from a vinyl ester unit by hydrolysis, alcoholysis, or the like. Therefore, depending on the conditions for converting vinyl ester units into vinyl alcohol units, vinyl ester units may remain in the vinyl alcohol resin. Therefore, the vinyl alcohol resin may contain vinyl ester units other than the structural unit having an ethylenically unsaturated group.

Examples of vinyl esters of the above vinyl ester units include vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versatate, vinyl caproate, vinyl caprylate, vinyl laurate, and palmitin. Examples include vinyl acid, vinyl stearate, vinyl oleate, vinyl benzoate, and among these, vinyl acetate is preferred from an industrial standpoint.

The vinyl alcohol resin used in the present invention may further contain structural units other than the ethylenically unsaturated group-containing structural unit, vinyl alcohol unit, and vinyl ester unit, as long as the effects of the present invention are obtained. good. The other structural unit is, for example, a structural unit derived from another monomer copolymerizable with the vinyl ester. Other monomers include ethylenically unsaturated monomers. The structural unit derived from another monomer may be a structural unit convertible into a structural unit having an ethylenically unsaturated group. Examples of ethylenically unsaturated monomers include α-olefins such as ethylene, propylene, n-butene, isobutylene, and 1-hexene; acrylic acid and its salts; methyl acrylate, ethyl acrylate, and n-propyl acrylate. , acrylic acid esters such as i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, and octadecyl acrylate; methacrylic acid and its salts Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, methacrylate Methacrylic acid esters such as octadecyl acid; acrylamide, N-methylacrylamide, N-ethylacrylamide, N,N-dimethylacrylamide, diacetone acrylamide, acrylamide propane sulfonic acid and its salts, acrylamide propyldimethylamine and its salts (e.g. methacrylamide, N-methyl methacrylamide, N-ethyl methacrylamide, methacrylamide propane sulfonic acid and its salts, methacrylamide propyldimethylamine and its salts (e.g. quaternary salts); methyl vinyl ether, ethyl vinyl ether, n - Vinyl ethers such as propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, stearyl vinyl ether, 2,3-diacetoxy-1-vinyloxypropane; acrylonitrile, methacrylo Vinyl cyanides such as nitrile; Vinyl halides such as vinyl chloride and vinyl fluoride; Vinylidene halides such as vinylidene chloride and vinylidene fluoride; Allyl acetate, 2,3-diacetoxy-1-allyloxypropane, chloride Examples include allyl compounds such as allyl; unsaturated dicarboxylic acids and salts or esters thereof such as maleic acid, itaconic acid, and fumaric acid; vinylsilyl compounds such as vinyltrimethoxysilane; isopropenyl acetate; and combinations thereof.

There is no particular restriction on the arrangement order of the structural unit having an ethylenically unsaturated group, the vinyl alcohol unit, and any other structural units in the vinyl alcohol resin. It may be a combination, an alternating copolymer, or the like.

The molecular weight of the vinyl alcohol resin used in the present invention is not particularly limited, but the number average molecular weight (Mn) is preferably 5,000 to 200,000, more preferably 7,000 to 180,000, More preferably, it is 8,000 to 150,000. If Mn is less than 5,000, sufficient durability may not be imparted to the coating layer obtained by the production method. If Mn exceeds 200,000, the durability of water resistance and/or water absorption of the coating layer obtained by the production method may decrease. Mn can be calculated as a value measured with an HFIP column using polymethyl methacrylate as a standard substance, for example, by gel permeation chromatography (GPC).

The viscosity average degree of polymerization of the vinyl alcohol resin used in the present invention, measured in accordance with JIS K6726 (1994), is not particularly limited, but is preferably 100 to 5,000, more preferably 200 to 4,000. It is 000. When the viscosity average degree of polymerization is less than 100, sufficient durability may not be imparted to the coating layer obtained by the production method. When the viscosity average degree of polymerization exceeds 5,000, there is a risk that more advanced technology will be required to produce such a vinyl alcohol resin, and it may be difficult to maintain industrial productivity.

The degree of saponification of the vinyl alcohol resin used in the present invention is not particularly limited, but is preferably 60 to 99.95 mol%, more preferably 70 to 99.9 mol%, and even more preferably 80 to 99.5 mol%. , particularly preferably 85 to 99.0 mol%, most preferably 88 to 98.5 mol%. If the degree of saponification of the vinyl alcohol resin is less than 60 mol%, sufficient durability may not be imparted to the coating layer obtained using the vinyl alcohol resin. When the degree of saponification of the vinyl alcohol resin exceeds 99.95 mol%, the durability of water resistance and/or water absorption of the coating layer obtained using the vinyl alcohol resin may decrease.

The method for producing the vinyl alcohol resin used in the present invention is not particularly limited. For example, by reacting polyvinyl alcohol with a compound having an ethylenically unsaturated group in its structure (for example, a compound having a carboxylic acid), a partial structure represented by the above formula (I) is introduced into the side chain. A modified polyvinyl alcohol resin can be produced. Specific examples of such reactions include transesterification of polyvinyl alcohol and acrylic ester or methacrylic ester; reaction of polyvinyl alcohol with acrylic acid, methacrylic acid, 4-pentenoic acid, or 10-undecenoic acid; polyvinyl alcohol and acrylic anhydride or methacrylic anhydride; and polyvinyl alcohol and acryloyl chloride or methacryloyl chloride.

(aqueous medium)
The aqueous medium used in the invention is, for example, water or an aqueous alcohol solution. Also, examples of water include pure water, ion exchange water, distilled water, RO water and tap water, and combinations thereof. The alcohol contained in the aqueous alcohol solution is, for example, a lower alcohol having 1 to 3 carbon atoms, such as methanol, ethanol, and isopropyl alcohol. The concentration of alcohol contained in the alcohol aqueous solution is preferably set low, for example, 40% by mass or less, preferably 35% by mass or less, more preferably 30% by mass or less.

The content of the aqueous medium contained in the coating composition is not particularly limited, but is preferably 100 parts by mass to 100,000 parts by mass, more preferably 200 parts by mass to 50,000 parts by mass, and more preferably 100 parts by mass to 100,000 parts by mass, and More preferably, it is 400 parts by mass to 10,000 parts by mass. If the content of the aqueous medium is less than 100 parts by mass, for example, the polyvinyl alcohol resin in the coating composition may not be sufficiently dissolved, and there is a risk that the coating properties may deteriorate. When the content of the aqueous medium exceeds 100,000 parts by mass, a large amount of energy may be required to volatilize the aqueous medium from the coating composition.

In addition to the above aqueous medium, the coating composition may contain a ketone such as acetone, an ether such as diethyl ether, or a combination thereof as a diluent. The content of these diluents can be appropriately selected by those skilled in the art.

(Polymerizable component)
The polymerizable component includes at least one compound selected from the group consisting of a crosslinking agent and a polymerization initiator.

(Crosslinking agent)
As the crosslinking agent, known crosslinking agents for polyvinyl alcohol resins can be used. Specifically, aliphatic polyisocyanates such as hexamethylene diisocyanate, dodecane diisocyanate, and isophorone diisocyanate; aromatic polycyanate compounds such as xylylene diisocyanate, tolylene diisocyanate, and diphenylmethane diisocyanate; ethylene glycol diacrylate, triethylene glycol diisocyanate, and the like; Acrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, bisphenol A diglycidyl ether Terminal acrylic acid adduct, pentaerythritol triacrylate, pentaerythritol tetraacrylate, polyester diacrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, tris(2-(2,3-dihydroxypropoxy)ethyl)isocyanurate triacrylate , polyacrylates such as tris(2-hydroxyethyl)isocyanurate diacrylate, cyclohexanedimethanol diacrylate, and tricyclodecane dimethanol diacrylate; titanium compounds such as titanium triethanolaminate and titanium lactate; zirconium compounds; maleic acid , polycarboxylic acid compounds such as citric acid; bis(β-hydroxyethyl)sulfone, and the like.

When the polyvinyl alcohol resin constituting the coating composition has a polymerization-reactive group, a crosslinking agent known in the art for crosslinking the polymerization-reactive group can be used. Preferably, the crosslinking agent includes a compound having two or more thiol groups in one molecule, a compound having two or more amino groups in one molecule, and the like. Examples of compounds having two or more thiol groups in one molecule include 1,2-ethanedithiol, 1,3-propanedithiol, 1,4-butanedithiol, 2,3-butanedithiol, 1,5 -Pentanedithiol, 1,6-hexanedithiol, 1,10-decanedithiol, 2,3-dihydroxy-1,4-butanedithiol, ethylene bis(thioglycolate), ethylene glycol bis(3-mercaptopropionate) , 1,4-butanediol bis(thioglycolate), 2,2'-thiodiethanethiol, 3,6-dioxa-1,8-octanedithiol (DODT), 3,7-dithia-1,9- Nonanedithiol, 1,4-benzenedithiol, trimethylolpropane tris (3-mercaptopropionate), trimethylolpropane tris (thioglycolate), pentaerythritol tetrakis (mercaptoacetate), dipentaerythritol hexakis (3-mercaptopropionate), mercaptopropionate), thiocol (manufactured by Toray Fine Chemicals, Inc.), and the like. Examples of compounds having two or more amino groups in one molecule include ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 2,2-dimethyl-1,3-propanediamine, 1, 2-diamino-2-methylpropane, 2-methyl-1,3-propanediamine, 1,2-diaminobutane, 1,4-diaminobutane, 1,3-diaminopentane, 1,5-diaminopentane, 1, 6-diaminohexane, 2-methyl-1,5-diaminopentane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1-methyl-1,8-diaminooctane, 1,10 -diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, bis(3-aminopropyl)ether, 1,2-bis(3-aminopropoxy)ethane, 1,3-bis(3-aminopropoxy) )-2,2-dimethylpropane, 2,2'-oxybis(ethylamine), 1,3-diamino-2-propanol, α,ω-bis(3-aminopropyl) polyethylene glycol ether, 1,2-diaminocyclohexane , 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 4-(2-aminoethyl)cyclohexylamine, isophoronediamine , 1,4-phenylenediamine, and the like.

The content of the crosslinking agent that can constitute the coating composition is not particularly limited, but for example, it is preferably 0.1 parts by mass to 20 parts by mass, more preferably 0.5 parts by mass, based on 100 parts by mass of the vinyl alcohol resin. Parts by mass to 10 parts by mass. If the content of the crosslinking agent is less than 0.1 part by mass, a crosslinked structure by the vinyl alcohol resin may not be sufficiently formed, and the resulting coating layer may not achieve satisfactory water resistance. If the content of the crosslinking agent exceeds 20 parts by mass, crosslinking of the resulting coating layer may not proceed any further, and productivity may be impaired.

(Polymerization initiator)
When the polyvinyl alcohol resin constituting the coating composition has a polymerization-reactive group, a polymerization initiator known in the art can be used as the polymerizable component instead of the above-mentioned crosslinking agent. Examples of the polymerization initiator include thermal polymerization initiators and photopolymerization initiators.

As a thermal polymerization initiator, azo polymerization initiators and peroxide polymerization initiators, which are common in radical polymerization, can be used, but in order to obtain a coating layer with excellent transparency and physical properties, a thermal polymerization initiator that does not generate gas can be used. Oxide polymerization initiators are preferred. Additionally, a redox polymerization initiator in combination with a reducing agent may be used. As mentioned above, if a redox polymerization initiator is used, it is possible to cause crosslinking by stimulation of mixing a peroxide polymerization initiator and a reducing agent.

When using a peroxide-based polymerization initiator, a highly water-soluble peroxide-based polymerization initiator is preferred. Specific examples include inorganic peroxides such as ammonium persulfate, potassium persulfate, and sodium persulfate. Known reducing agents can be used as a reducing agent to be combined as a redox polymerization initiator, but among these, highly water-soluble N,N,N',N'-tetramethylethylenediamine, sodium sulfite, sodium hydrogen sulfite, and hydrosal Preferred examples include phytosodium.

As already mentioned, peroxide-based polymerization initiators that do not generate gas are preferably used, but if the transparency and physical properties of the coating layer are not particularly important, water-soluble azo-based polymerization initiators may also be used. good. Specifically, for example, 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride (trade name "VA-044", manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 2, 2'-azobis[2-(2-imidazolin-2-yl)propane] disulfate dihydrate (trade name "VA-044B", manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 2,2'-azobis [2-Methylpropionamidine] dihydrochloride (trade name "V-50", manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine ] Tetrahydrate (product name "VA-057", manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 2,2'-azobis[2-(2-imidazolin-2-yl)propane] (product name "VA-057", manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 061'', manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide] (trade name ``VA-086'', manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 2,2'-azobis(4-cyanopentanoic acid) (trade name "V-501", manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and the like.

As photopolymerization initiators, propiophenone compounds such as 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone; 4'-phenoxy-2,2-dichloroacetophenone, 4'- t-Butyl-2,2,2-trichloroacetophenone, 2,2-diethoxyacetophenone, 2-hydroxy-2-methylpropiophenone, 2-hydroxy-2-methyl-1-(4'-dodecylphenyl)- 1-propanone, 1-[4'-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propanone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-4'-methylthio-2-morpholino Acetophenone compounds such as propiophenone; Benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, benzyl dimethyl ketal; benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 2 -Chlorobenzophenone, 2,2'-dichlorobenzophenone, 4-hydroxybenzophenone, 4,4'-dihydroxybenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3'-dimethyl-4-methoxybenzophenone, Michler's ketone Benzophenone compounds such as [4,4'-bis(dimethylamino)benzophenone] and 4,4'-bis(diethylamino)benzophenone; 2-chlorothioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, 2,4-dichloro Thioxanthone compounds such as thioxanthone, 2,4-diethylthioxanthone, and 2,4-diisopropylthioxanthone; Quinone compounds such as 9,10-phenanthrenequinone, camphorquinone (2,3-bornedione), and 2-ethylanthraquinone; 2. Examples include 4,6-trimethylbenzoyldiphenylphosphine oxide; benzyl.

The content of the polymerization initiator that can constitute the coating composition is not particularly limited, but for example, it is preferably 0.1 parts by mass to 10 parts by mass, more preferably 0.1 parts by mass, per 100 parts by mass of the vinyl alcohol resin. The amount is 2 parts by mass to 5 parts by mass. If the content of the polymerization initiator is less than 0.1 parts by mass, for example, even if the vinyl alcohol resin is appropriately irradiated with active energy rays, a crosslinked structure will not be sufficiently formed, and the resulting coating layer will not be satisfactory. There is a risk that the desired water resistance will not be achieved. If the content of the polymerization initiator exceeds 10 parts by mass, crosslinking within the resulting coating layer may not proceed any further, and productivity may be impaired.

(Coating composition)
In the present invention, the polyvinyl alcohol resin, aqueous medium, and polymerizable component may be mixed in advance using means known in the art and prepared in the form of a coating composition.

Note that the coating composition may contain other components in addition to the polyvinyl alcohol resin, aqueous medium, and polymerizable component. Examples of other ingredients include fillers such as calcium carbonate, clay, titanium oxide, talc, and silica, processing stabilizers, weathering stabilizers, colorants, ultraviolet absorbers, antioxidants, antistatic agents, and flame retardants. , plasticizers, other thermoplastics, lubricants, fragrances, antifoaming agents, deodorants, extenders, stripping agents, mold release agents, reinforcing agents, fungicides, preservatives, radical generators and crystallization rates. Included are retarders, catalysts, coupling agents, and combinations thereof. The content of the other components in the coating composition is not particularly limited, and an appropriate amount can be appropriately selected by a person skilled in the art within a range that does not inhibit the effects of the present invention exerted by the polyvinyl alcohol resin, aqueous medium, and polymerizable component. obtain.

(Base material)
The base material used in the present invention may itself be colorless or colored, for example, it is a transparent molded body that maintains visibility from one side to the other. Good too. The base material may also be a plate-like member (for example, a window material) having a smooth plane, or a member formed to have a predetermined shape (for example, a vehicle headlight cover, a vehicle headlight cover, etc.). windshield and rear glass). The substrate can also, for example, improve strength, fire resistance or fire protection, sound insulation, and/or security; absorb or reflect heat radiation; provide non-reflection or low reflection of light; prevent or reduce temperature conduction. ; etc., metal wires, fillers, base material additives, etc. may be contained in arbitrary proportions.

Examples of the base material include, but are not particularly limited to, glass molded bodies and resin molded bodies.

Examples of glass moldings include float glass, tempered glass, heat-resistant glass, fireproof glass, design glass, colored glass, laminated glass, frosted glass, double-glazed glass, non-reflective glass, low-reflective glass, wired glass, and wired glass. Examples include molded bodies made of glasses such as glass, high transmittance glass, heat ray reflective glass, electromagnetic shielding glass, and sapphire glass.

Examples of resin molded bodies include polyethylene (PE) resin, polypropylene (PP) resin, polymethyl methacrylate (PMMA) resin, polyethylene terephthalate (PET) resin, polycarbonate (PC) resin, polyvinyl chloride (PVC) resin, Moldings made from thermoplastic or thermosetting resins such as polystyrene (PS) resin, alicyclic acrylic resin, alicyclic polyolefin resin, poly-4-methylterpene-1 resin, vinylidene chloride resin, transparent epoxy resin, etc. One example is the body.

The thickness of the base material is not particularly limited, and an appropriate thickness can be selected by those skilled in the art. For example, when the substrate is placed in close contact with the coating composition, the side on which the coating composition is applied may be subjected to surface treatment such as polishing using methods well known to those skilled in the art in order to enhance the adhesion. may be carried out. Note that an intermediate layer made of an adhesive or the like known in the art may be arranged between the base material and the coating composition.

Regarding the arrangement of the coating composition on the substrate, the coating composition is preferably arranged on the outermost layer of the substrate in order for the resulting coating layer to effectively exhibit antifogging properties. Furthermore, for example, when the substrate is composed of a member such as a window material, the coating composition may be placed only on the outer surface, only the inner surface, or both the outer and inner surfaces of the substrate. It's okay.

The coating composition is placed on the substrate on the surface or portion of the substrate where antifogging properties are desired, for example, by spray coating, roll coating, spin coating, etc. , air knife coating, blade coating, brushing, dipping, and other methods known in the art can be used.

This forms an uncrosslinked layer with the coating composition disposed on the substrate.

The uncrosslinked layer obtained above is preferably provided with a uniform thickness over the entire base material. The thickness of the uncrosslinked layer is preferably 6 μm to 400 μm, more preferably 6 μm to 200 μm, even more preferably 6 μm to 100 μm. If the thickness of the uncrosslinked layer is less than 6 μm, it may be difficult to uniformly arrange it on the substrate, and the coating layer obtained after crosslinking may not be able to provide uniform antifogging properties. When the thickness of the uncrosslinked layer exceeds 400 μm, more coating composition is required to form the coating layer, and a large amount of energy may be required to volatilize the aqueous medium from the coating composition. .

In the present invention, it is preferable that the uncrosslinked layer has an adjusted moisture content. Here, the term "water content" used in this specification is the proportion (mass%) of the entire aqueous medium contained in the entire uncrosslinked layer, and the aqueous medium contains water and other substances than the above water. When this is the case, it refers to the ratio (% by mass) of the total amount of water and substances other than water contained in the entire uncrosslinked layer.

In the present invention, the water content of the uncrosslinked layer is in the range of 10% by mass to 95% by mass. The lower limit of the water content of the uncrosslinked layer is preferably 17% by mass or more, more preferably 24% by mass or more, even more preferably 50% by mass or more, and most preferably 80% by mass or more. Further, the upper limit of the water content of the uncrosslinked layer is preferably 90% by mass or less, more preferably 87.5% by mass or less, and even more preferably 86% by mass or less. If the water content of the uncrosslinked layer is less than 10% by mass, for example, even if the vinyl alcohol resin contained in the uncrosslinked layer is appropriately irradiated with active energy rays, a crosslinked structure will not be sufficiently formed, resulting in There is a risk that satisfactory water resistance of the coating layer may not be achieved. If the water content of the uncrosslinked layer exceeds 95% by mass, for example, even if the vinyl alcohol resin contained in the uncrosslinked layer is appropriately irradiated with active energy rays, crosslinking within the resulting coating layer will not proceed any further. In fact, there is a risk of a lack of productivity.

In the present invention, various methods can be employed to set the water content of the uncrosslinked layer within the above range. For example, the content of the aqueous medium in preparing the coating composition may be strictly controlled, and the crosslinking described below may be performed immediately after forming the uncrosslinked layer. Alternatively, after forming the uncrosslinked layer, the moisture content of the uncrosslinked layer may be adjusted within the above range by temporarily storing it in an environment controlled to a specific humidity. Alternatively, after forming the uncrosslinked layer, the uncrosslinked layer may be exposed to hot air, infrared rays, a heating cylinder, or a combination thereof to adjust the moisture content of the uncrosslinked layer to within the above range. Humidity adjustment and heating require a certain amount of energy, so in order to avoid this, the moisture content immediately after the formation of the uncrosslinked layer is adjusted to be within the above range, and immediately after the formation of the uncrosslinked layer, It is preferable to perform crosslinking as described below.

In the present invention, the uncrosslinked layer is then crosslinked to form a coating layer.

Crosslinking of an uncrosslinked layer is performed, for example, by applying energy to the layer.

Examples of energy that may be applied include active energy radiation and heat, and combinations thereof. Here, specific examples of active energy rays include light rays, electromagnetic waves, particle beams, and combinations thereof. Examples of light rays include far ultraviolet rays, ultraviolet (UV), near ultraviolet rays, visible light, infrared rays, etc. Examples of electromagnetic waves include X-rays, gamma rays, etc., and examples of particle beams include electron beams. (EB), proton beams (α rays), neutron beams, etc. Among these active energy rays, ultraviolet rays and electron beams are preferable, and ultraviolet rays are more preferable, from the viewpoints of appropriate curing speed of the applied uncrosslinked layer and easy availability of irradiation equipment.

The amount and time of energy that can be applied is not particularly limited. An appropriate amount and time can be appropriately selected by those skilled in the art depending on the type of energy employed, the size of the uncrosslinked layer to be applied, etc.

This causes crosslinking of the uncrosslinked layer.

In addition, in the present invention, the layer on the base material may be dried as necessary during and after the crosslinking. The means that may be used for such drying are not particularly limited and include, for example, those for exposing hot air, infrared radiation, and heated cylinders, and combinations thereof.

In this way, a coating layer is formed from the uncrosslinked layer.

(coating layer)
The coating layer is preferably provided with a substantially uniform thickness over the entire base material. The thickness of the coating layer is 3 μm or more and less than 20 μm when the water content is adjusted to less than 10% by mass (for example, 0.1% by mass or more and less than 10% by mass). When the water content is adjusted to the above-mentioned water content, it is preferably 4 μm or more and 18 μm or less, and more preferably 5 μm or more and 16 μm or less, because each of antifogging properties, hardness, and residual stress can be kept within appropriate ranges. If the thickness of the coating layer is less than 3 μm, there is a risk that the coating layer will not be able to provide uniform antifogging properties on the substrate, and the antifogging properties will decrease, and furthermore, when formed on a soft substrate such as plastic, Residual stress may increase and warpage may occur. If the thickness of the coating layer exceeds 20 μm, more coating liquid will be required to form the coating layer, and the increased thickness may reduce the hardness when applied to a hard substrate such as glass. be.

(Anti-fog member)
For example, the antifogging member manufactured as described above includes a base material and a coating layer.

The base material and the coating layer may be in direct contact with each other, or may have one or more intermediate layers interposed therebetween. In addition, when an intermediate layer is present, it is preferable that the intermediate layer has good adhesion to both the base material and the coating layer, and maintains appropriate transparency. An example of such an intermediate layer is an adhesive layer made of a known adhesive.

As described above, the coating layer constituting the antifogging member of the present invention is obtained from a coating composition containing a polyvinyl alcohol resin, an aqueous medium, and a polymerizable component, and has a thickness of 3 μm or more and less than 20 μm, preferably It has a thickness of 4 μm or more and 18 μm or less, more preferably 5 μm or more and 16 μm or less.

Furthermore, the coating layer constituting the antifogging member of the present invention has a predetermined residual stress. Here, the term "residual stress of the coating layer" used in this specification refers to the state in which the coating layer is disposed on the base material (i.e., in the form of an antifogging member), Cut out a strip-shaped sample piece, condition the humidity in an environment of 23°C and 40% RH for one week, and place an aluminum plate on a desk within a width of 3 mm from one end of the short side of the obtained sample piece. In the grounded state, measure the length (L/2) and height (ξ) to the other end, and combine these values with the base value of the sample piece before humidity conditioning. From the thickness of the material (h ₁ ), the thickness of the coating layer (h ₂ ), and the elastic modulus E ₁ of the base material, the radius of curvature (ρ) can be calculated according to the following formula, and then the residual stress (σ _c ) can be calculated. .
Radius of curvature ρ=L ² /(8×ξ)
Residual stress σ _c = (E ₁ × h ₁ ³ ) / (12 × h ₂ ) × 2 / (ρ (h ₁ + h ₂ )) × [1 + 1/3 (h ₁ / (h ₁ + h ₂ )) ² ]

In the present invention, the coating layer preferably has a residual stress of 0.1 MPa to 10 MPa, more preferably 0.2 MPa to 5 MPa. Controlling the residual stress in the coating layer to be less than 0.1 MPa is not always technically easy, and may require more advanced and complicated manufacturing equipment. When the residual stress of the coating layer exceeds 10 MPa, it becomes difficult to suppress a decrease in hardness when the coating layer is provided on a hard base material, and it becomes difficult to suppress warping of the base material when it is provided on a soft base material. It may be difficult to do so.

(Application)
The antifogging member of the present invention can be applied to various uses where it is desired to avoid the occurrence of fogging on the surface of the member, for example. Examples of uses include, but are not limited to, exterior materials, interior materials, windows, mirrors, and headlight covers for vehicles (e.g., automobiles, trains), aircraft, ships; architectural (e.g., buildings, houses) or structures; Exterior wall materials for objects (e.g. exterior wall panels, window glass), interior materials for buildings (e.g. wallpaper, mirrors), window materials (e.g. window glass), mirrors for bathrooms or washrooms; showcases, aquariums, incubators; information equipment, furniture , home appliances, displays, various consumer products; kitchen and plumbing products (e.g. sinks, ventilation fan hoods, bathroom products); blades for wind generators (e.g. propellers, multi-wings, sails); curved mirrors for road traffic; security cameras. lenses and housings; digital camera lenses and housings; broadcast camera lenses and housings; eyeglass lenses and frames; sunglass lenses and frames; goggles for sports or leisure (e.g. skiing, snowboarding, snorkeling, scuba diving) ; Safety glasses, face shields; Medical lenses; Helmets for industrial use, sports use, and motorcycles; Various sensor covers; Agricultural house construction materials (e.g., plastic sheets, plastic films, window glass); and the like.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way. In addition, "%" and "parts" in Examples and Comparative Examples represent "% by mass" and "parts by mass", respectively, unless otherwise specified.

(Base material used)
The following materials were used as the base material.
・PET film (manufactured by Mitsubishi Chemical Corporation, product name: Diafoil S100, thickness 100 μm)
・Cerium oxide polished soda glass plate (manufactured by Climbing Co., Ltd., product name: soda glass plate 100 x 150, thickness 2 mm)

(Evaluation of water content of uncrosslinked layer)
After measuring the mass (W1) after the coating composition was placed on the substrate, the mass (W2) after vacuum drying the coating composition at 80° C. for 6 hours was measured. Using these values, the water content of the uncrosslinked layer was calculated according to the following formula.
Moisture content (%) of uncrosslinked layer = (W1-W2)/W2×100

(Coating layer thickness evaluation)
The thickness of the base material before placing the coating composition and the total thickness of the coating layer and the base material are measured using a micrometer (Coolant proof micrometer MDC-MX manufactured by Mitutoyo Co., Ltd.), and the coating layer is calculated from the difference. The thickness was calculated.

(Evaluation of water elution rate and water absorption capacity of coating layer)
The coating layer peeled off from the sample (PET film with coating layer) obtained in the example or comparative example was immersed in boiling water at a temperature of 100° C. for 1 hour. Thereafter, the mass (W3) after taking it out and wiping off the surface water was measured, and the mass (W4) after vacuum drying it at 80° C. for 6 hours was measured. Using these values W3 and W4 and the pre-measured dry mass (W5) of the film before immersion in water, the water elution rate and water absorption capacity of the cured film were calculated according to the following formula, and the following Water resistance and water absorption were determined based on standards.
Water elution rate (%)=(W5-W4)/W5×100
A: Water elution rate was less than 10% B: Water elution rate was 10% or more and less than 30% C: Water elution rate was 30% or more and less than 50% D: Water elution rate was 50% E: Water elution rate was 80% or more Water absorption capacity (times) = W3/W4
A: The water absorption capacity was 15 times or more. B: The water absorption capacity was 10 times or more and less than 15 times. C: The water absorption capacity was less than 10 times. D: Partial elution occurred, and the shape of the film was maintained. No E: The film was completely dissolved.

(Evaluation of anti-fog properties)
Cover the mouth of a 100 mL beaker containing 100 mL of 40°C hot water with the sample obtained in the example or comparative example (soda glass substrate with coating layer) with the coating layer facing downward, and cover the bottom and sides of the beaker. was immersed in a 40°C water bath and left in a 40°C atmosphere. Thereafter, as shown in FIG. 1, the label was looked into from above to confirm visibility, and the antifogging property was determined based on the following criteria, with the time that the sample covered the beaker mouth being set as 0 minutes.
A: Did not start to cloud within 9 minutes B: Did not start to cloud within 6 minutes C: Did not start to cloud within 3 minutes D: Did not start to cloud within 1 minute E: Coating Membrane elution was observed

(Pencil hardness evaluation)
The samples (glass base material with coating layer) obtained in Examples or Comparative Examples were tested in accordance with JIS K5600-5-4 using uni series 9H to 6B manufactured by Mitsubishi Pencil Co., Ltd. at an angle of 45° and a load of 750 g. It was measured with

(Evaluation of residual stress)
The sample (PET base material with coating layer) obtained in the example or comparative example was cut into a strip of 5 cm x 7 cm, and the humidity was conditioned for one week in an environment of 23° C. and 40% RH. Place an aluminum plate within a width of 3 mm from one end of the short side of the obtained strip, and with it grounded on a desk, measure the length (L/2) and height (ξ) to the other end. was measured. Using these values, the thickness of the base material of the anti-fog coated PET (h ₁ ), the thickness of the coating layer (h ₂ ), and the base material elastic modulus of PET E ₁ (3920 MPa) that were measured in advance, , the radius of curvature (ρ) was calculated according to the following formula, and then the residual stress (σ _c ) was calculated.
Radius of curvature ρ=L ² /(8×ξ)
Residual stress σ _c = (E ₁ × h ₁ ³ ) / (12 × h ₂ ) × 2 / (ρ (h ₁ + h ₂ )) × [1 + 1/3 (h ₁ / (h ₁ + h ₂ )) ² ]

(Example 1)
(Preparation of coating composition)
In a reactor equipped with a stirrer, a reflux tube, and an addition port, 493.0 parts by mass of methacrylic acid, 17.0 parts by mass of acetic acid, 56.7 parts by mass of ion-exchanged water, 1.3 parts by mass of p-methoxyphenol, and para. 4.2 parts by mass of toluenesulfonic acid monohydrate were sequentially charged, and while stirring at room temperature, 100 parts by mass of commercially available polyvinyl alcohol resin (viscosity average degree of polymerization 1700, degree of saponification 98.5 mol%) was added and stirred. While stirring, the temperature was raised to 80° C., and the mixture was reacted in a slurry state for 7 hours. Thereafter, the modified polyvinyl alcohol resin was collected by cooling to room temperature, filtering the contents, washing with a large amount of methanol, and drying at 40°C and 1.3 Pa for 20 hours to obtain a modification rate of 1 mol%. A methacrylic acid-modified polyvinyl alcohol, which is a modified polyvinyl alcohol-based resin, was obtained. The obtained modified polyvinyl alcohol resin was dissolved in water to prepare a 10% aqueous solution, and then a photoinitiator, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropylene, was added as a polymerization initiator. Piophenone (HEMP) was added and dissolved in an amount of 1 part by mass to 100 parts by mass of the modified polyvinyl alcohol resin to prepare a coating composition.

The coating composition obtained above was placed on each substrate (soda glass plate or PET film) using a film applicator so that the thickness after drying was 10 μm to form an uncrosslinked layer.

Next, the uncrosslinked layer was stored for one week under the conditions of 23° C. and 63% RH to adjust the moisture content of the uncrosslinked layer to 10% by mass, and then the uncrosslinked layer was exposed to ultraviolet rays at 3000 mJ/cm. A sample in which a coating layer was formed on each base material by irradiating at an intensity of ² to crosslink the modified polyvinyl alcohol resin in the uncrosslinked layer, and then drying at 60°C for 1 hour under atmospheric pressure. I got it.

(evaluation)
The various evaluations described above were performed using the obtained samples. The results are shown in Table 1.

(Example 2)
A coating layer was formed on each substrate in the same manner as in Example 1, except that the uncrosslinked layer was stored for one week at 23 ° C. and 80% RH and the moisture content was adjusted to 14% by mass. Samples were obtained and subjected to the various evaluations described above. The results are shown in Table 1.

(Example 3)
A coating layer was formed on each substrate in the same manner as in Example 1, except that the uncrosslinked layer was stored for one week at 23 ° C. and 95% RH and the moisture content was adjusted to 26% by mass. Samples were obtained and subjected to the various evaluations described above. The results are shown in Table 1.

(Example 4)
After forming the uncrosslinked layer, a sample with a coating layer formed on each base material was prepared in the same manner as in Example 1, except that the uncrosslinked layer was dried with hot air to adjust the water content to 58% by mass. The various evaluations described above were conducted. The results are shown in Table 1.

(Example 5)
After forming the uncrosslinked layer, a sample with a coating layer formed on each base material was prepared in the same manner as in Example 1, except that the uncrosslinked layer was adjusted to have a water content of 78% by mass by hot air drying. The various evaluations described above were conducted. The results are shown in Table 1.

(Example 6)
Other than using an uncrosslinked layer that was prepared so that the aqueous solution concentration was 15% when preparing the coating composition, was not stored for one week under the conditions of 23 ° C. and 63% RH, and had a water content of 85% by mass. obtained samples in which a coating layer was formed on each base material in the same manner as in Example 1, and conducted the various evaluations described above. The results are shown in Table 1.

(Example 7)
A coating layer was formed on each substrate in the same manner as in Example 1, except that it was not stored for one week under the conditions of 23 ° C. and 63% RH, and an uncrosslinked layer with a moisture content of 90% by mass was used. Samples were obtained and subjected to the various evaluations described above. The results are shown in Table 1.

(Example 8)
The coating composition was arranged so that the thickness after drying (moisture content less than 10% by mass) was 6 μm, and the coating composition was not stored for one week under the conditions of 23°C and 63% RH, and was coated with a coating composition having a moisture content of 90% by mass. Samples in which a coating layer was formed on each base material were obtained in the same manner as in Example 1 except that a crosslinked layer was used, and the various evaluations described above were performed. The results are shown in Table 1.

(Example 9)
The coating composition was arranged so that the thickness after drying (moisture content less than 10% by mass) was 4 μm, and the coating composition was not stored for one week under the conditions of 23°C and 63% RH, and was coated with a coating composition having a moisture content of 90% by mass. Samples in which a coating layer was formed on each base material were obtained in the same manner as in Example 1 except that a crosslinked layer was used, and the various evaluations described above were performed. The results are shown in Table 1.

(Example 10)
A coating composition was prepared by dissolving the modified polyvinyl alcohol resin in a mixed solvent of water and methanol in a mass ratio of 95:5, and the coating composition was stored for one week at 23°C and 63% RH to reduce the water content. Samples in which a coating layer was formed on each base material were obtained in the same manner as in Example 1, except that an uncrosslinked layer having 90% by mass was used, and the various evaluations described above were performed. The results are shown in Table 1.

(Example 11)
An uncrosslinked layer was prepared in the same manner as in Example 7, except that a thermal initiator, potassium peroxodisulfate (KPS), was used instead of HEMP as a polymerization initiator. Next, the uncrosslinked layer was heat-treated at 80°C for 30 minutes in a closed system to crosslink the modified polyvinyl alcohol resin, and dried under atmospheric pressure at 60°C for 1 hour to form a coating layer on each base material. A formed sample was obtained. This sample was subjected to the various evaluations described above. The results are shown in Table 1.

(Example 12)
Commercially available polyvinyl alcohol resin (viscosity average degree of polymerization 1700, degree of saponification 98.5 mol%) was used as an unmodified polyvinyl alcohol resin, and titanium (IV) bis(hydrogen lactate) dihydroxide (manufactured by Matsumoto Fine Chemical Co., Ltd.) was used as a crosslinking agent. Samples in which a coating layer was formed on each base material were obtained in the same manner as in Example 11 except that Orgatics TC-310 (hereinafter referred to as TC-310) was used. This sample was subjected to the various evaluations described above. The results are shown in Table 1.

(Comparative example 1)
A coating layer was formed on each substrate in the same manner as in Example 1, except that the water content was adjusted to 6% by weight by storing it for one week at 23° C. and 40% RH, and an uncrosslinked layer was used. A formed sample was obtained, and the various evaluations described above were performed on this sample. The results are shown in Table 1.

(Comparative example 2)
A coating layer was formed on each substrate in the same manner as in Example 7, except that it was placed on each substrate so that the thickness of the coating layer after drying (moisture content less than 10% by mass) was 20 μm. A sample was obtained, and the various evaluations described above were performed on this sample. The results are shown in Table 1.

(Comparative example 3)
A coating layer was formed on each substrate in the same manner as in Example 7, except that it was placed on each substrate so that the thickness of the coating layer after drying (moisture content less than 10% by mass) was 2 μm. A sample was obtained, and the various evaluations described above were performed on this sample. The results are shown in Table 1.

(Comparative example 4)
In a reactor equipped with a stirrer, a reflux tube, and an addition port, 476.3 parts by mass of methacrylic acid, 62.4 parts by mass of acetic acid, 28.4 parts by mass of ion-exchanged water, 1.3 parts by mass of p-methoxyphenol, and para. 9.1 parts by mass of toluenesulfonic acid monohydrate were sequentially charged, and 100 parts by mass of commercially available polyvinyl alcohol resin (number average degree of polymerization 300, degree of saponification 82 mol%) was added while stirring at room temperature. A coating composition was prepared in the same manner as in Example 1. The obtained coating layer was placed on each substrate so that the thickness after drying (moisture content less than 10% by mass) was 20 μm, and the formed uncrosslinked layer was coated at 25° C. and 50% RH. Samples with coating layers formed on each base material were obtained in the same manner as in Example 1 except that they were stored for a week, and the various evaluations described above were performed on these samples. The results are shown in Table 1.

(Comparative example 5)
Samples in which a coating layer was formed on each base material were obtained in the same manner as in Example 1, except that no polymerization initiator was added, and the various evaluations described above were performed on these samples. The results are shown in Table 1.

As shown in Table 1, the coating layers in the samples prepared in Examples 1 to 12 all had excellent water resistance and water absorption, and also had excellent antifogging performance and hardness, and low residual stress. had. On the other hand, as shown in Comparative Example 1, when the water content of the uncrosslinked layer was adjusted to less than 10% by mass, the pencil hardness and residual stress were good, but the elution rate was low and the water resistance was poor. Further, as in Comparative Examples 2 to 4, when the thickness of the coating layer was less than 3 μm, the pencil hardness was good, but the residual stress was high. When the thickness of the coating layer exceeded 20 μm, the antifogging property was good, but the pencil hardness was poor. Furthermore, as in Comparative Example 5, those that were not crosslinked had low water resistance, and the coating layer was completely eluted in boiling water.

According to the present invention, it is possible to provide a laminated member provided with a coating film having excellent antifogging properties. The laminated material can be used, for example, as vehicle glass. The present invention is useful, for example, in the field of resin molding, the field of automobiles, railways, aircraft, and ships, the field of medical products, the field of agriculture and horticulture, the field of electricity, the field of architecture, and the like.

Claims (9)

A method for manufacturing an anti-fog member, comprising:
a step of disposing a coating composition containing a polyvinyl alcohol resin, an aqueous medium, and a polymerizable component on a substrate to form an uncrosslinked layer; and a step of crosslinking the uncrosslinked layer to obtain a coating layer.
including;
The moisture content of the uncrosslinked layer is 10% by mass or more and 95% by mass or less based on the total mass of the uncrosslinked layer,
The polymerizable component is at least one compound selected from the group consisting of a crosslinking agent and a polymerization initiator,
A manufacturing method, wherein the coating layer has a thickness of 3 μm or more and less than 20 μm when the water content is adjusted to less than 10% by mass. The manufacturing method according to claim 1, wherein the polyvinyl alcohol resin is a modified polyvinyl alcohol resin. The manufacturing method according to claim 1 or 2, wherein the polyvinyl alcohol resin is a modified polyvinyl alcohol resin having an ethylenically unsaturated group in a side chain. The manufacturing method according to any one of claims 1 to 3, wherein the ethylenically unsaturated group contains a partial structure represented by the following formula (I).

[In formula (I), R ¹ , R ² and R ³ are each independently a hydrogen atom, a methyl group, a carboxyl group, or a carboxymethyl group, and X is an oxygen atom or -N(R ⁴ )- , R ⁴ is a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and * is a bond of the ethylenically unsaturated group] The manufacturing method according to any one of claims 1 to 4, wherein the modified polyvinyl alcohol resin is a polyvinyl alcohol resin containing a structural unit represented by the following formula (II) or (III).

[In formula (II), R ¹ , R ² and R ³ are each independently a hydrogen atom, a methyl group, a carboxyl group, or a carboxymethyl group, and X is an oxygen atom or -N(R ⁴ )- , R ⁴ is a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, Y represents a divalent hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and * indicates the modified It is a bond of a structural unit in polyvinyl alcohol resin],

[In formula (III), R ¹ , R ² and R ³ are each independently a hydrogen atom, a methyl group, a carboxyl group, or a carboxymethyl group, and * represents a bond between structural units in the modified polyvinyl alcohol resin. [It is a hand] The manufacturing method according to any one of claims 1 to 5, wherein the base material is made of at least one material selected from the group consisting of resin, glass, and metal. The crosslinking step is performed by applying energy to the uncrosslinked layer,
The manufacturing method according to any one of claims 1 to 6, wherein the energy is at least one selected from the group consisting of active energy rays and heat. An anti-fog member,
including a base material and a coating layer,
The coating layer is obtained from a coating composition containing a polyvinyl alcohol resin, an aqueous medium, and a polymerizable component,
An antifogging member, wherein the coating layer has a thickness of 3 μm or more and less than 20 μm when the water content is adjusted to less than 10% by mass, and has a residual stress of 0.1 MPa to 10 MPa. A method for suppressing the occurrence of warping of an anti-fog member, the method comprising:
A step of disposing a coating composition containing a polyvinyl alcohol resin, an aqueous medium, and a polymerizable component on a substrate to form an uncrosslinked layer, and crosslinking the uncrosslinked layer to form a coating layer on the substrate. a step of obtaining the antifogging member in which is arranged;
including;
The moisture content of the uncrosslinked layer is 10% by mass or more and 90% by mass or less based on the total mass of the uncrosslinked layer,
The polymerizable component is at least one compound selected from the group consisting of a crosslinking agent and a polymerization initiator,
A method in which the coating layer has a thickness of 3 μm or more and less than 20 μm when the water content is adjusted to less than 10% by mass.