WO2021230005A1 - Transparent material having antifogging layer - Google Patents

Abstract

Disclosed is a transparent material not only having excellent anti-fog performance but also showing excellent durability in exposure tests simulating various usage environments. The transparent material includes a transparent substrate and an antifogging layer formed on the substrate, wherein the antifogging layer is a layer formed from a cured product of a crosslinkable composition containing: (A) a modified polyvinyl alcohol resin having an ethylenically unsaturated group in a side chain thereof; and (B) a metal oxide component, and the content of the modified polyvinyl alcohol resin (A) in the crosslinkable composition is at least 30 mass%.

Description

Transparent material with anti-fog layer

The present invention relates to a transparent material provided with an anti-fog layer, and more particularly to a transparent material having an anti-fog layer containing a hydrophilic resin having excellent anti-fog performance and durability on the surface layer.

For transparent materials such as glass, a material with an anti-fog layer is used to ensure visibility depending on the usage environment. A water-repellent material may be used for the anti-fog layer, but in a usage environment where it is particularly important to prevent the formation of minute droplets, a hydrophilic anti-fog layer is formed to absorb water. A method is taken to prevent the formation of microdroplets by a mechanism.

Among the transparent materials provided with such a hydrophilic anti-fog layer, an organic-inorganic hybrid anti-fog layer made of a water-absorbent resin and an inorganic compound such as silica is used as a material having both scratch resistance and anti-fog properties. A transparent material has been proposed. For example, Patent Documents 1 and 2 disclose an example of a transparent material in which a polyvinyl acetal resin is used as a water-absorbent resin and silica particles are blended.

WO2015 / 186360 Gazette WO2019 / 082695 Gazette

However, the transparent article described in Patent Document 1 has insufficient water-absorbing properties because a polyvinyl acetal resin modified with benzaldehyde is used to make the water-absorbing resin water-resistant. In addition, since unnecessary components such as a cross-linking agent were required for water resistance, there was a problem from the viewpoint of anti-fog sustainability. Further, in the anti-fog glass article described in Patent Document 2, an example in which a resin obtained by acetalizing polyvinyl alcohol with acetaldehyde is used as a curable polyvinyl acetal resin for an anti-fog film is disclosed, but its water resistance is sufficient. However, it is considered that there is room for improvement in durability.

An object of the present invention is to solve the above-mentioned problems, and an object thereof is to have excellent anti-fog performance and sustain anti-fog effect (hereinafter, also referred to as "anti-fog sustainability"). It is an object of the present invention to provide a transparent material which not only has an excellent durability but also exhibits excellent durability in an exposure test assuming various usage environments.

（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）
［３］前記変性ポリビニルアルコール樹脂（Ａ）が、以下の式（ＩＩ）または（ＩＩＩ）で表される構造単位を含む、［１］または［２］に記載の透明材料。

（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樹脂（Ａ）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樹脂（Ａ）における構造単位の結合手である）
［４］前記変性ポリビニルアルコール樹脂（Ａ）が、式（Ｉ）で表される前記部分構造を０．２～５モル％の割合で含有する、［１］～［３］のいずれかに記載の透明材料。
［５］前記架橋性組成物において、前記変性ポリビニルアルコール樹脂（Ａ）１００質量部に対し、前記金属酸化物成分（Ｂ）を５～１００質量部含む、［１］～［４］のいずれかに記載の透明材料。
［６］前記金属酸化物成分（Ｂ）の少なくとも一つがＳｉの酸化物成分である、［１］～［５］のいずれかに記載の透明材料。
［７］前記防曇層の膜厚が１～５０μｍである、［１］～［６］のいずれかに記載の透明材料。
［８］前記透明基材がガラスである、［１］～［７］のいずれかに記載の透明材料。
［９］前記ガラスが車両用ガラスである、［８］に記載の透明材料。
［１０］透明基材と、前記基材上に形成された防曇層と、を備える透明材料の製造方法であって、
　側鎖にエチレン性不飽和基を有する変性ポリビニルアルコール樹脂（Ａ）及び金属酸化物成分（Ｂ）を含む架橋性組成物を含む塗工液を透明基材上に塗布して、次いで硬化させる工程を含み、
　前記架橋性組成物に含まれる変性ポリビニルアルコール樹脂（Ａ）の含有量が３０質量％以上である、方法。 The present invention includes the following inventions.
[1] A transparent base material and an anti-fog layer formed on the base material are provided.
The antifogging layer is a layer formed from a cured product of a crosslinkable composition containing a modified polyvinyl alcohol resin (A) having an ethylenically unsaturated group in the side chain and a metal oxide component (B), and the crosslinking is performed. A transparent material in which the content of the modified vinyl alcohol resin (A) contained in the sex composition is 30% by mass or more.
[2] The transparent material according to [1], 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 independently hydrogen atoms, methyl groups, carboxyl groups or carboxymethyl groups, respectively, and X is an oxygen atom or -N (R ⁴ )-. There, R ⁴ is a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, * represents a bond of the ethylenically unsaturated group)
[3] The transparent material according to [1] or [2], wherein the modified polyvinyl alcohol resin (A) contains a structural unit represented by the following formula (II) or (III).

(In formula (II), R ¹ , R ² and R ³ are independently hydrogen atoms, methyl groups, carboxyl groups or carboxymethyl groups, respectively, and X is an oxygen atom or -N (R ⁴ )-. Yes, 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 * represents the modification. It is a bond of structural units in the polyvinyl alcohol resin (A))

(In the formula (III), R ¹ , R ² and R ³ are independently hydrogen atoms, methyl groups, carboxyl groups or carboxymethyl groups, respectively, and * is a structural unit in the modified polyvinyl alcohol resin (A). Is a bond)
[4] Described in any one of [1] to [3], wherein the modified polyvinyl alcohol resin (A) contains the partial structure represented by the formula (I) in a proportion of 0.2 to 5 mol%. Transparent material.
[5] Any of [1] to [4], wherein the crosslinkable composition contains 5 to 100 parts by mass of the metal oxide component (B) with respect to 100 parts by mass of the modified polyvinyl alcohol resin (A). The transparent material described in.
[6] The transparent material according to any one of [1] to [5], wherein at least one of the metal oxide components (B) is an oxide component of Si.
[7] The transparent material according to any one of [1] to [6], wherein the anti-fog layer has a film thickness of 1 to 50 μm.
[8] The transparent material according to any one of [1] to [7], wherein the transparent base material is glass.
[9] The transparent material according to [8], wherein the glass is vehicle glass.
[10] A method for producing a transparent material comprising a transparent base material and an anti-fog layer formed on the base material.
A step of applying a coating liquid containing a crosslinkable composition containing a modified polyvinyl alcohol resin (A) having an ethylenically unsaturated group in the side chain and a metal oxide component (B) onto a transparent substrate and then curing the mixture. Including
A method in which the content of the modified polyvinyl alcohol resin (A) contained in the crosslinkable composition is 30% by mass or more.

According to the present invention, not only has excellent anti-fog performance and long-lasting anti-fog effect (hereinafter, also referred to as "anti-fog persistence"), but also in exposure tests assuming various usage environments. It is possible to provide a transparent material showing excellent durability.

The transparent material of the present invention includes a transparent base material and an anti-fog layer formed on the base material. The antifogging layer is a layer formed from a cured product of a crosslinkable composition containing a modified polyvinyl alcohol resin (A) having an ethylenically unsaturated group in the side chain and a metal oxide component (B). The content of the modified polyvinyl alcohol resin (A) contained in the crosslinkable composition is 30% by mass or more.

[Anti-fog layer]
The anti-fog layer included in the transparent material of the present invention is a single-layer film formed on a transparent substrate. The antifogging layer, which is a monolayer film, is formed of a cured product of a crosslinkable composition containing at least a modified polyvinyl alcohol resin (A) having an ethylenically unsaturated group in the side chain and a metal oxide component (B). There is. The water absorption of the modified polyvinyl alcohol resin (A) can inhibit the formation of water droplets on the surface of the anti-fog layer to exhibit anti-fog performance, and the metal oxide component (B) can impart scratch resistance. I can. Further, the crosslinkable composition used as a material for the anti-fog layer may further contain other functional components, if necessary. Hereinafter, each component will be described.

(Modified polyvinyl alcohol resin (A))
The structure of the ethylenically unsaturated group contained in the side chain of the modified polyvinyl alcohol resin (A) is not particularly limited, and examples thereof include unsaturated groups having radical polymerizable properties. A cured product can be obtained from the crosslinkable composition by utilizing the excellent crosslinkability of the modified polyvinyl alcohol resin (A) based on the ethylenically unsaturated group. In particular, such an ethylenically unsaturated group preferably contains a partial structure represented by the following formula (I).

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

^{In the above formula (I), R 1} and R ² are preferably hydrogen atoms because of the good cross-linking reactivity, and from the viewpoint of viscosity stability of the coating stock solution before forming the anti-fog layer. Therefore, it is preferable that R ^{3 is a methyl group.} Further, 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 having 1 to 3 carbon atoms. The group is mentioned. 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 a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. In the above formula (I), X is preferably an oxygen atom because of its excellent reactivity.

In the present invention, the modified polyvinyl alcohol resin (A) preferably contains a structural unit represented by the following formula (II) or (III).

(In formula (II), R ¹ , R ² and R ³ are independently hydrogen atoms, methyl groups, carboxyl groups or carboxymethyl groups, respectively, and X is an oxygen atom or -N (R ⁴ )-. Yes, 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 * is a modified polyvinyl. It is a bond of structural units in the alcohol resin (A))

(In formula (III), R ¹ , R ² and R ³ are independently hydrogen atoms, methyl groups, carboxyl groups, or carboxymethyl groups, respectively, and * is a structural unit in the modified polyvinyl alcohol resin (A). It is a bond)

In the formula (II) and (III), because of the crosslinking reaction is good, it is preferred that R ¹ and R ² are hydrogen atoms, R ³ from the viewpoint of viscosity stability of the coating stock solution It is preferably a methyl group.

Further, 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 having 1 to 3 carbon atoms. The group is mentioned. 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 a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. In the above formula (II), X is preferably an oxygen atom because of its excellent reactivity.

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

In the present invention, the modified polyvinyl alcohol resin (A) has a structure represented by the formula (III) among the modified polyvinyl alcohol resins (A) containing the structural units represented by the above formula (II) or (III). It is preferably a modified polyvinyl alcohol resin (A) having a unit.

More specific examples of the structural unit including the partial structure represented by the above formula (I) and the structural unit represented by the above formulas (II) and (III) include the structural units shown below. Be done.

(In the formula, * is a bond of structural units in the modified polyvinyl alcohol resin (A)).

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

In the present invention, the lower limit of the content of the structural unit having an ethylenically unsaturated group (for example, the structural unit including the partial structure represented by the formula (I)) with respect to all the structural units of the modified polyvinyl alcohol resin (A) is particularly low. Although not limited, the total structural unit of the modified polyvinyl alcohol resin (A) is 100 mol%, preferably 0.05 mol% or more, more preferably 0.1 mol% or more, still more preferably 0.2. It is mol% or more, and particularly preferably 0.5 mol% or more. Further, the upper limit of the content of the structural unit having an ethylenically unsaturated group (for example, the structural unit including the partial structure represented by the formula (I)) is not particularly limited, but the entire structural unit of the modified polyvinyl alcohol resin (A). Is 100 mol%, preferably 8 mol% or less, more preferably 5 mol% or less, and particularly preferably 3 mol% or less. The transparent material of the present invention has excellent anti-fog durability and durability because the content of the structural unit having an ethylenically unsaturated group is within the range composed of such a lower limit and an upper limit. Can be done. Further, the modified polyvinyl alcohol resin (A) may have a structural unit having two or more kinds of ethylenically unsaturated groups in all the structural units thereof. For example, when having two or more kinds of ethylenically unsaturated groups, the total amount of the contents of the structural units having these two or more kinds of ethylenically unsaturated groups may be within the range composed of the above lower limit and upper limit. preferable. The term "structural unit" in the present specification refers to a repeating unit constituting the polymer. For example, the "vinyl alcohol unit" and "vinyl ester unit" described later are also included as examples of the "structural unit".

In the present invention, the lower limit of the vinyl alcohol unit with respect to the total structural unit of the modified polyvinyl alcohol resin (A) is not particularly limited, but the total structural unit of the modified polyvinyl alcohol resin (A) is 100 mol%, preferably 60 mol%. The above is more preferably 70 mol% or more, further preferably 80 mol% or more, and particularly preferably 85 mol% or more. The upper limit of the content of the vinyl alcohol unit is not particularly limited, but the total structural unit of the modified polyvinyl alcohol resin (A) is 100 mol%, preferably 99.95 mol% or less, and more preferably 99. It is 9 mol% or less, more preferably 99.5 mol% or less, and particularly preferably 99.0 mol%. When the content of the vinyl alcohol unit is within the range composed of such a lower limit and an upper limit, the transparent material of the present invention can have both excellent anti-fog durability and durability.

Vinyl alcohol units can be derived from vinyl ester units by hydrolysis, alcohol decomposition, etc. Therefore, the vinyl ester unit may remain in the modified polyvinyl alcohol resin (A) depending on the conditions for converting the vinyl ester unit to the vinyl alcohol unit. Therefore, the modified polyvinyl alcohol resin (A) may contain a vinyl ester unit other than the structural unit having an ethylenically unsaturated group.

Examples of the vinyl ester of the vinyl ester unit include vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versatic acid, vinyl caproate, vinyl caprilate, vinyl laurate, and palmitin. Examples thereof include vinyl acetate, vinyl stearate, vinyl oleate, vinyl benzoate and the like, and among these, vinyl acetate is preferable from an industrial point of view.

The modified polyvinyl alcohol resin (A) may further contain structural units other than the structural unit having an ethylenically unsaturated group, the vinyl alcohol unit and the vinyl ester unit, as long as the effect of the present invention can be obtained. The other structural unit is, for example, a structural unit derived from another monomer copolymerizable with vinyl ester. Examples of other monomers include ethylenically unsaturated monomers. The structural unit derived from the other monomer may be a structural unit that can be converted into a structural unit having an ethylenically unsaturated group. Examples of the ethylenically unsaturated monomer include α-olefins such as ethylene, propylene, n-butyl, isobutylene, and 1-hexene; acrylic acid and salts thereof; 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, octadecyl acrylate; methacrylic acid and salts thereof. Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, methacryl Methacrylate esters such as octadecyl acid; acrylamide, N-methylacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide, diacetoneacrylamide, acrylamide propanesulfonic acid and its salts, acrylamidepropyldimethylamine and its salts (eg 4). Grade salt); methacrylamide, N-methylmethacrylate, N-ethylmethacrylate, methacrylamidepropanesulfonic acid and its salts, methacrylamidepropyldimethylamine and its salts (eg, quaternary salts); methylvinyl ether, ethylvinyl 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 cyanide such as nitriles; 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 Allyl compounds such as allyl; unsaturated dicarboxylic acids such as maleic acid, itaconic acid, fumaric acid and salts thereof or esters thereof; vinylsilyl compounds such as vinyltrimethoxysilane; isopropenyl acetate; and combinations thereof.

The arrangement order of the structural unit having an ethylenically unsaturated group, the vinyl alcohol unit, and any other structural unit in the modified polyvinyl alcohol resin (A) is not particularly limited, and the modified polyvinyl alcohol resin (A) is a random copolymer. It may be any of a polymer, a block copolymer, an alternating copolymer and the like.

The molecular weight of the modified polyvinyl alcohol resin (A) is not particularly limited, but the number average molecular weight (Mn) is preferably 4,400 to 220,000. If Mn is less than 4,400, sufficient durability may not be imparted to the anti-fog layer. Mn is more preferably 8800 or more, still more preferably 13,200 or more, particularly preferably 22,000 or more, and most preferably 40,000 or more. On the other hand, if Mn exceeds 220,000, the anti-fog sustainability may decrease. Mn is more preferably 180,000 or less, still more preferably 150,000 or less, and particularly preferably 100,000 or less. Mn can be calculated as a value measured by an HFIP-based column using polymethylmethacrylate as a standard substance, for example, by a gel permeation chromatography (GPC) method.

The viscosity average degree of polymerization of the modified polyvinyl alcohol resin (A) measured in accordance with JIS K6726 (1994) is not particularly limited, but is preferably 100 to 5,000, more preferably 200 to 4,000. .. If the viscosity average degree of polymerization is less than 100, it may not be possible to impart sufficient durability to the anti-fog layer. If the viscosity average degree of polymerization exceeds 5,000, more advanced techniques may be required for the production of such a modified polyvinyl alcohol resin (A), and it becomes difficult to maintain industrial productivity. There is.

The degree of saponification of the modified polyvinyl alcohol resin (A) is not particularly limited, but is preferably 60 to 99.95 mol%, more preferably 70 to 99.9 mol%, still more preferably 80 to 99.5 mol%, and particularly preferably. Is 85 to 99.0 mol%, most preferably 88 to 98.5 mol%. If the saponification degree of the modified polyvinyl alcohol resin (A) is less than 60 mol%, it may not be possible to impart sufficient durability to the anti-fog layer. If the saponification degree of the modified polyvinyl alcohol resin (A) exceeds 99.95 mol%, the anti-fog persistence may decrease.

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

The modified polyvinyl alcohol resin (A) has a content of 30% by mass or more in the crosslinkable composition used in the present invention. By containing 30% by mass or more of the modified polyvinyl alcohol resin (A), anti-fog property is exhibited for a long period of time. From the viewpoint of hardness, water absorption and anti-fog property of the anti-fog layer, it is preferably 40% by mass or more, more preferably 50% by mass or more, particularly preferably 60% by mass or more, and 95% by mass or less, more preferably 90% by mass. By mass or less, particularly preferably 85% by mass or less.

(Metal oxide component (B))
The antifogging layer is formed of a cured product of a crosslinkable composition containing a modified polyvinyl alcohol resin (A) having an ethylenically unsaturated group in the side chain and a metal oxide component (B).

The metal oxide component (B) is, for example, an oxide component of at least one metal element selected from Si, Ti, Zr, Ta, Nb, Nd, La, Ce and Sn, and is preferably an oxide of Si. It is a component (silica component). The crosslinkable composition used as the material of the anti-fog layer preferably contains 5 to 200 parts by mass of the metal oxide component (B) with respect to 100 parts by mass of the modified polyvinyl alcohol resin (A), and contains 10 to 100 parts by mass. Is preferable. The metal oxide component (B) is a component necessary for ensuring the strength of the anti-fog layer, particularly scratch resistance, but if the content thereof is excessive, the anti-fog sustainability of the anti-fog layer is lowered.

Examples of the metal oxide component (B) include metal oxide fine particles and a metal oxide component derived from a hydrolyzable metal compound. It is preferable to use at least one metal oxide component derived from the metal oxide fine particles and the hydrolyzable metal compound in combination. When used in combination, the mass ratio (metal oxide fine particles / metal oxide component derived from the hydrolyzable metal compound) is preferably 10/90 to 90/10.

(Metal oxide fine particles)
As one aspect of the metal oxide component (B), metal oxide fine particles can be mentioned. The metal oxide constituting the metal oxide fine particles is, for example, an oxide of at least one metal element selected from Si, Ti, Zr, Ta, Nb, Nd, La, Ce and Sn, and preferably silica fine particles. Is. The silica fine particles can be contained in the crosslinkable composition by using, for example, colloidal silica.

If the average particle size of the metal oxide fine particles is too large, the film may become cloudy, and if it is too small, it will be agglomerated and difficult to disperse uniformly. From this point of view, the preferred average particle size of the metal oxide fine particles is 1 to 20 nm, particularly 5 to 20 nm. Here, the average particle size of the metal oxide fine particles is described in the state of primary particles. Further, the average particle size of the metal oxide fine particles is determined by measuring the particle size of 50 fine particles arbitrarily selected by observation using a scanning electron microscope and adopting the average value. If the content of the metal oxide fine particles is excessive, the water absorption amount of the entire layer is lowered, and in addition to the deterioration of the antifog sustainability, light scattering may occur due to the formation of agglomerates and the layer may become cloudy. The metal oxide fine particles are preferably 0 to 250 parts by mass, more preferably 1 to 150 parts by mass, still more preferably 2 to 100 parts by mass, and particularly preferably 5 with respect to 100 parts by mass of the modified polyvinyl alcohol resin (A). It may be added in an amount of up to 60 parts by mass, and in some cases 10 to 30 parts by mass.

(Metal oxide component derived from hydrolyzable metal compound)
As one aspect of the metal oxide component (B), a metal oxide component derived from a hydrolyzable metal compound can be mentioned. Examples of the hydrolyzable metal compound include a hydrolyzable silicon compound and a hydrolyzable titanium compound.

Examples of the hydrolyzable silicon compound include silicon alkoxide, chlorosilane, acetoxysilane, alkenyloxysilane and aminosilane, and silicon alkoxide is particularly preferable.

Examples of the hydrolyzable titanium compound include titanium alkoxide, titanium chelate compound, and titanium acylate. The titanium alkoxide is, for example, titanium tetraisopropoxide, titanium tetra-n-butoxide, or titanium tetraoctoxide. Examples of the titanium chelate compound are titanium acetylacetonate, ethyl titaniumacetoacetate, titanium octylene glycol, titanium triethanolamine, and titanium lactate. Titanium lactate may be an ammonium salt (titanium lactate ammonium). Titanium acylate is, for example, titanium stearate. Preferred hydrolyzable titanium compounds are titanium chelate compounds, especially titanium lactate.

The hydrolyzable silicon compound may be a compound represented by the following formula (V).
SiY ₄ (V)
Y is a hydrolyzable functional group, preferably at least one selected from an alkoxyl group, an acetoxy group, an alkenyloxy group, an amino group and a halogen atom. A preferred example of the hydrolyzable silicon compound is tetraalkoxysilane, more specifically tetraalkoxysilane having an alkoxy group having 1 to 4 carbon atoms. The tetraalkoxysilane is, for example, tetramethoxysilane, tetraethoxysilane (sometimes referred to as TEOS), tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetraisobutoxysilane, tetra-. At least one selected from sec-butoxysilane and tetra-tert-butoxysilane.

The hydrolyzable metal compound is hydrolyzed or partially hydrolyzed, and at least a part thereof is polycondensed to supply a metal oxide component (B) in which a metal atom and an oxygen atom are bonded. This component firmly bonds the metal oxide fine particles and the modified polyvinyl alcohol resin (A), and contributes to the improvement of wear resistance, hardness, water resistance, etc. of the anti-fog layer. The metal oxide component (B) derived from the hydrolyzable metal compound is preferably 0 to 60 parts by mass, more preferably 0.1 to 50 parts by mass, and further, with respect to 100 parts by mass of the modified polyvinyl alcohol resin (A). It is more preferably in the range of 1 to 40 parts by mass, particularly preferably 3 to 30 parts by mass, and in some cases 4 to 20 parts by mass.

If the content of the metal oxide component (B) derived from tetraalkoxysilane is excessive, the anti-fog sustainability may decrease. The metal oxide component (B) derived from tetraalkoxysilane is preferably 0 to 30 parts by mass, more preferably 1 to 20 parts by mass, and even more preferably 3 with respect to 100 parts by mass of the modified polyvinyl alcohol resin (A). It is advisable to add in the range of ~ 10 parts by mass.

The metal oxide component (B) derived from the hydrolyzable titanium compound is preferably 0 to 30 parts by mass, more preferably 1 to 20 parts by mass, and even more preferably with respect to 100 parts by mass of the modified polyvinyl alcohol resin (A). May be added in the range of 3 to 10 parts by mass.

Another preferred example of the hydrolyzable silicone compound is a silane coupling agent. Silane coupling agents are silicon compounds having different reactive functional groups from each other. The reactive functional group is preferably a partially hydrolyzable functional group. The silane coupling agent may be, for example, a silicon compound having an epoxy group and / or an amino group and a hydrolyzable functional group, as well as an isocyanate group (which may be blocked), a mercapto group, and / or a polymerizable functional group. It is a silicon compound having. Preferred silane coupling agents include glycidyloxyalkyltrialkoxysilanes, aminoalkyltrialkoxysilanes, 3- (meth) acryloxypropyltrialkoxysilanes, 3- (meth) acryloxypropylmethyltrialkoxysilanes, and vinyltrialkoxysilanes. , 3-Isocyanate propyltrialkoxysilane, blocked isocyanatesilane, and the like can be exemplified. In these silane coupling agents, the alkylene group directly bonded to the silicon atom preferably has 1 to 3 carbon atoms.

The silane coupling agent firmly binds the modified polyvinyl alcohol resin (A), which is an organic component, to the metal oxide fine particles, which are inorganic components, to improve the wear resistance, hardness, water resistance, etc. of the antifogging layer. Can contribute. However, if the content of the metal oxide component (B) derived from the silane coupling agent is excessive, the anti-fog persistence of the anti-fog layer is lowered, and in some cases, the anti-fog layer becomes cloudy. When the metal oxide component (B) derived from the silane coupling agent is used, it is preferably 0 to 10 parts by mass, more preferably 0.05 to 5 parts by mass with respect to 100 parts by mass of the modified polyvinyl alcohol resin (A). , Even more preferably, it may be added in the range of 0.1 to 2 parts by mass.

The anti-fog layer provided in the transparent material of the present invention may further have anti-fouling performance and the like. For the purpose of imparting antifouling performance to the antifogging layer, the crosslinkable composition used in the present invention may contain a water repellent group derived from a water repellent group-containing hydrolyzable metal compound. As the water-repellent group-containing hydrolyzable metal compound, a water-repellent group-containing hydrolyzable silicon compound having a halogen atom, more specifically, a fluorine atom is suitable. The water-repellent group is preferably added so that the contact angle of water on the surface of the anti-fog layer is 70 degrees or more, preferably 80 degrees or more, and more preferably 90 degrees or more. The upper limit of the contact angle is not particularly limited, but is, for example, 150 degrees or less, for example, 120 degrees or less, and further 100 degrees or less.

(Crosslinking agent)
The crosslinkable composition used in the present invention may contain a crosslinker known in the art. The cross-linking agent is preferably a compound having two or more thiol groups in one molecule, a compound having two or more amino groups in one molecule, and polymerization of two or more in one molecule. Examples thereof include compounds having a sex group. 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-decandithiol, 2,3-dihydroxy-1,4-butanedithiol, ethylenebis (thioglycolate), ethyleneglycolbis (3-mercaptopropionate) , 1,4-Butanediolbis (thioglycolate), 2,2'-thiodietanthiol, 3,6-dioxa-1,8-octanedithiol (DODT), 3,7-dithia-1,9- Nonandithiol, 1,4-benzenedithiol, trimethylolpropanthris (3-mercaptopropionate), trimethylolpropanetris (thioglycolate), pentaerythritol tetrakis (mercaptoacetate), dipentaerythritol hexakiss (3- Mercaptopropionate), thiocol (manufactured by Toray Fine Chemicals Co., Ltd.) 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. Examples of the compound having two or more ethylenic double bonds in one molecule include alkylene glycol (meth) acrylates such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, and polyethylene glycol di (). Polyalkylene glycol (meth) acrylates such as meta) acrylates, N, N'-diethylene glycol di (meth) acrylates, pentaerythritol tetra (meth) acrylates, dipentaerythritol hexa (meth) acrylates, trimethyl propantri (meth) Acrylate, Ditrimethylol Propanetetra (meth) Acrylate, Tris {2- (Meta) Acryloyloxyethyl} Isocyanurate, 4,4'-Isopropyridendiphenol di (meth) Acrylate, Neopentyl Glycoldi (Meta) Acrylate, 1- (Acryloyloxy) -3- (methacryloyloxy) -2-propanol, glycerol di (meth) acrylate, bis {4- (meth) acryloylthiophenyl} sulfide, polyether tri (meth) acrylate, 1,4- Polyalkylene glycol diglycidyl such as butanediol glycidyl ether di (meth) acrylate and other alkylene glycol diglycidyl ether di (meth) acrylates, diethylene glycol diglycidyl ether di (meth) acrylate and polyethylene glycol diglycidyl ether di (meth) acrylate. Etherdi (meth) acrylates, N, N'-methylenebisacrylamide, N, N'-{[(2-acrylamide-2-[(3-acrylamidepropoxy) methyl] propan-1,3-diyl) bis ( Oxy)] (Propane-1,3-diyl)} Diacrylamide, N, N', N''-triacrylloy diethylenetriamine, N, N'-diacryloyl-4,7,10-trioxa-1,13- Examples thereof include tridecanediamine, N, N', N'', N'''-tetraacryloyltriethylenetetramine and the like.

The crosslinkable composition used in the present invention may further contain a crosslink structure derived from at least one crosslinker selected from an organoboron compound and an organozirconium compound. By introducing the crosslinked structure, the wear resistance, scratch resistance, and water resistance of the anti-fog layer are further improved.

The content of the cross-linking agent is not particularly limited, but is preferably 0.1 part by mass to 20 parts by mass, more preferably 0.5 part by mass to 10 parts by mass with respect to 100 parts by mass of the modified polyvinyl alcohol resin (A). It is a mass part. If the content of the cross-linking agent is less than 0.1 parts by mass, the cross-linked structure formed by the modified polyvinyl alcohol resin (A) may not be sufficiently formed, and the durability of the anti-fog layer may decrease. If the content of the cross-linking agent exceeds 20 parts by mass, the anti-fog durability may decrease. The crosslinkable composition used in the present invention can be crosslinked even in the absence of a crosslinking agent due to the modified polyvinyl alcohol resin (A). When the cross-linking agent is contained, the above-mentioned content may be adopted, but an embodiment in which the cross-linking agent is substantially not contained is also preferable. That is, the content of the cross-linking agent is preferably 0 to 0.1% by mass in the cross-linking composition.

(Photopolymerization initiator)
The crosslinkable composition used in the present invention may contain a photopolymerization initiator known in the art in place of or in addition to the crosslinker. The photopolymerization initiator is not particularly limited, but is a propiophenone-based compound 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-propanol, 1- [4'-(2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propanol, 1-hydroxycyclohexylphenylketone, 2-methyl-4' -Methylthio-2-acetophenone compounds such as morpholinopropiophenone; benzophenones such as benzoin, benzoinmethyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, benzyl dimethyl ketal; benzophenone, carboxybenzophenone and its salts, di Carboxybenzophenone and its salts, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 2-chlorobenzophenone, 2,2'-dichlorobenzophenone, 4-hydroxybenzophenone, 4,4'-dihydroxybenzophenone, 4-benzoyl-4' -Benzophenone compounds such as methyl-diphenylsulfide, 3,3'-dimethyl-4-methoxybenzophenone, Micheler ketone [4,4'-bis (dimethylamino) benzophenone], 4,4'-bis (diethylamino) benzophenone; thioxanthone , 1-Chloro-4-propoxythioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone and other thioxanthone compounds. Kinone compounds such as 9,10-phenanthrenquinone, camphorquinone (2,3-bornandione), 2-ethylanthraquinone; 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 1-benzyl-1-dimethylamino-1 -(4'-Morholinobenzoyl) propane, 2-morpholyl-2- (4'-methylmercapto) benzoylpropane, 4-benzoyl-4'-methyldiphenylsulfide, benzyl, ethyl Anthraquinone, phenylbiphenylketone, 1-hydroxy-1-benzoylcyclohexane (α-hydroxyalkylphenone), 2-hydroxy-2-benzoylpropane, 2-hydroxy-2- (4'-isopropyl) benzoylpropane, 4-butylbenzoyl Trichloromethane, 4-phenoxybenzoyl dichloromethane, methyl benzoyllate, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, 1- [4- (2-hydroxy) Ethoxy) -phenyl] -2-hydroxy-2-methyl-1-propane-1-one, 1,7-bis (9'-acridinyl) heptane, 9-n-butyl-3,6-bis (2'- Morphorinoisobutyroyl) carbazole, 2-methyl-4,6-bis (trichloromethyl) -s-triazine, 2-phenyl-4,6-bis (trichloromethyl) -s-triazine, 2-naphthyl-4,6 -Bis (trichloromethyl) -s-triazine, 2,2-bis (2-chlorophenyl) -4,5,4', 5'-tetraphenyl-1-2'-biimidazole, acylphosphine oxide, bisacylphosphine Examples thereof include oxides and triphenylphosphine oxides.

The photopolymerization initiator is not particularly limited, but is preferably 0.1 part by mass to 10 parts by mass, more preferably 0.2 part by mass to 5 parts by mass with respect to 100 parts by mass of the modified polyvinyl alcohol resin (A). It is a department. When the content of the photopolymerization initiator is less than 0.1 parts by mass, for example, even if the modified polyvinyl alcohol resin (A) is appropriately irradiated with UV light, a crosslinked structure formed by the resin (A) is sufficiently formed. However, the durability of the anti-fog layer may decrease. If the content of the photopolymerization initiator exceeds 10 parts by mass, the anti-fog sustainability may decrease.

(Other ingredients)
The crosslinkable composition used in the present invention may contain other additives. Examples of the additive include glycols such as glycerin and ethylene glycol having a function of improving anti-fog property. Additives include surfactants, leveling agents, UV absorbers, colorants, defoamers, preservatives, fillers, processing stabilizers, weathering stabilizers, colorants, UV absorbers, antioxidants, antistatic agents. Agents, flame retardants, plasticizers, other thermoplastic resins, lubricants, fragrances, defoamers, deodorants, bulking agents, release agents, mold release agents, reinforcing agents, fungicides, preservatives, radical generators And crystallization rate retardants, as well as combinations thereof.

[Transparent substrate]
Examples of the transparent base material include a glass plate and a resin plate. The transparent substrate may be colored transparent or colorless and transparent, but is preferably colorless and transparent.

(Glass plate)
The glass plate may be, for example, a float plate glass most commonly used in the fields of vehicles, construction and industry. The glass plate does not have to be colored, but may be colored in green, bronze, or the like. Further, it may be processed or processed into tempered glass, laminated glass, double glazing and the like. The shape of the main surface may be either a flat surface or a curved surface. The plate thickness is, for example, 1 to 12 mm, preferably 3 to 10 mm for construction, and 1 to 5 mm for vehicles.

When a glass plate is used for a vehicle window glass, a ceramic shielding layer may be formed on the peripheral edge of the vehicle window glass in order to improve the design of the vehicle. The ceramic shielding layer also plays a role of preventing deterioration of the resin material such as the adhesive and the foam material for joining the window glass to the vehicle body due to ultraviolet rays. The ceramic shielding layer is formed by applying a ceramic paste and firing. The transparent material of the present invention may be a glass plate with such a ceramic shielding layer together with the anti-fog layer.

(Resin plate)
As the resin plate, an acrylic resin plate typified by a polycarbonate plate and a polymethylmethacrylate plate is suitable. The thickness of the resin plate is preferably 2 to 8 mm, and preferably 3 to 6 mm. The surface of the resin plate may be surface-treated to improve the adhesion to the anti-fog layer. The surface treatment of the resin plate includes corona discharge treatment, plasma treatment, chromic acid treatment (wet), flame treatment, hot air treatment, oxidation treatment such as ozone / ultraviolet irradiation treatment, sandblasting method, and unevenness treatment such as solvent treatment. Treatment with various adhesive primers and the like can be mentioned. Among these treatments, the corona discharge treatment is preferable from the viewpoint of effectiveness and operability.

[Thickness of anti-fog layer]
The film thickness of the anti-fog layer may be appropriately adjusted according to the required anti-fog characteristics and the like. The anti-fog layer preferably has a film thickness of 1 to 50 μm, preferably 2 to 20 μm, and particularly 3 to 10 μm.

[Anti-fog layer film formation]
The anti-fog layer is formed of a cured product of a crosslinkable composition containing a modified polyvinyl alcohol resin (A) and a metal oxide component (B). The crosslinkable composition can be cured to form an anti-fog layer by applying a coating liquid for forming an anti-fog layer onto the above-mentioned transparent substrate and then curing the cross-linking composition. For curing, irradiation with high energy rays or electromagnetic waves, or heating at a predetermined temperature can be mentioned. After the coating liquid is applied, the coating layer on the substrate is preferably in a water-containing state. Since the coating layer is in a water-containing state, the modified polyvinyl alcohol resin (A) contained in the coating composition in the coating layer is crosslinked in the water-containing state by a treatment such as irradiation with high energy rays. As a result, the water absorption ratio of the cured product after cross-linking is increased, and the anti-fog property is improved. Therefore, it is preferable that the coating layer after the aqueous solution of the coating composition is applied onto the substrate is subjected to a treatment such as high-energy ray irradiation described later in a water-containing state. If necessary, the applied coating liquid may be dried before curing. Further, after curing, a drying step may be performed. Further, high temperature and high humidity treatment may be further performed before or after curing, if necessary.

The coating liquid is a liquid containing a crosslinkable composition, and usually further contains a solvent. As the solvent used for preparing the coating liquid and the coating method of the coating liquid, conventionally known materials and methods may be used. Examples of the solvent include organic solvents and water. The content of the solvent in the coating liquid is preferably 50 to 90% by mass. The method for preparing the coating liquid is not particularly limited, and for example, a solvent may be added to the crosslinkable composition, or each component of the crosslinkable composition may be added to the solvent.

In the coating process of applying the coating liquid, it is preferable to keep the relative humidity of the atmosphere at less than 40% and further at 30% or less. Keeping the relative humidity low can prevent the anti-fog layer from absorbing excessive moisture from the atmosphere. If a large amount of water is absorbed from the atmosphere, the remaining water that has entered the matrix of the anti-fog layer may reduce the strength of the anti-fog layer.

After applying the coating liquid, the coating layer (anti-fog layer before becoming a cured product) on the transparent substrate is preferably in a water-containing state. Since the coating layer is in a water-containing state, the modified polyvinyl alcohol resin (A) contained in the coating layer is crosslinked in a water-containing state by a treatment such as high-energy ray irradiation described later. As a result, the water absorption ratio of the cured product after cross-linking is increased, and the anti-fog property is improved. Therefore, it is preferable that the coating layer is subjected to a treatment such as high-energy ray irradiation, which will be described later, in a water-containing state. The cured product of the crosslinkable composition obtained by such a method contains a component derived from the solvent of the coating liquid in addition to the component derived from the crosslinkable composition. The content of the component derived from the solvent of the coating liquid in the cured product of the crosslinkable composition is preferably 1 to 20% by mass.

After that, the coating layer is irradiated with high energy rays or electromagnetic waves, or heated at a predetermined temperature, so that the crosslinkable composition can be made into a cured product. By this method, cross-linking is triggered, so that the formation of the cured product can be controlled. Examples of the high energy ray include an electron beam and the like. Examples of electromagnetic waves include ultraviolet rays (UV light), visible light, and infrared rays. Examples of the temperature when subjected to heating include 50 to 200 ° C. Above all, it is preferable to use UV light because a cured product of the crosslinkable composition containing the modified polyvinyl alcohol resin (A) can be obtained in a more homogeneous state without requiring complicated equipment or the like. As for UV light, not only the light emitted from a light source such as an ultraviolet lamp is irradiated, but also the UV light may be irradiated through sunlight by exposing it to the outside.

A further drying step (after curing) may be provided after the crosslinkable composition is cured. The drying step preferably includes an air-drying step and a heat-drying step accompanied by heating. The air-drying step may be carried out by exposing the anti-fog layer to an atmosphere in which the relative humidity is kept below 40% and further below 30%. The air-drying step can be carried out as a non-heating step, in other words, at room temperature. When the antifogging layer contains a hydrolyzable silicon compound, in the heat-drying step, a dehydration reaction involving silanol groups contained in the hydrolyzate of the silicon compound and hydroxyl groups present on the transparent article proceeds, and the dehydration reaction proceeds. A matrix structure (Si—O bond network) consisting of silicon atoms and oxygen atoms develops. The temperature applied in the heat-drying step is, for example, 100 to 200 ° C., and the heating time is 1 minute to 1 hour.

When forming the anti-fog layer, a high-temperature and high-humidity treatment step may be carried out as appropriate. By implementing the high temperature and high humidity treatment step, it may be easier to achieve both anti-fog property and strength of the anti-fog layer. The high temperature and high humidity treatment step can be carried out by holding the atmosphere at 50 to 100 ° C. and a relative humidity of 60 to 95% for 5 minutes to 1 hour, for example. The high temperature and high humidity treatment step may be carried out after the coating step and before the curing, after the curing and before the drying step (after the curing), or in the drying step (after the curing). It may be carried out later. In the drying step (after curing), a high-temperature and high-humidity treatment step may be carried out between the air-drying step and the heat-drying step. Further, a heat treatment step may be further carried out after the high temperature and high humidity treatment step. This additional heat treatment step can be carried out, for example, by holding in an atmosphere of 80 to 180 ° C. for 5 minutes to 1 hour.

Further, the formed anti-fog layer may be washed and / or wiped with a compress as necessary. Specifically, it can be carried out by exposing the surface of the anti-fog layer to a stream of water or wiping it with a cloth soaked in water. Pure water is suitable as the water used for these. By this step, dust, dirt and the like adhering to the surface of the anti-fog layer can be removed to obtain a clean coating film surface.

The transparent material of the present invention can be used for various applications in which it is desired to avoid the occurrence of fogging on the surface of the material. Examples of applications include, but are not limited to, windows and headlight covers for vehicles (eg, automobiles, trains), aircraft, ships; window materials for architecture (eg, buildings, houses); bathrooms or Toilet mirrors; Road traffic curve mirrors; Surveillance cameras, security camera lenses and their covers; Digital camera lenses; Broadcast camera lenses; Eyeglass lenses; Sunglasses lenses; Sensors; Sports or leisure (eg skiing, snowboarding, snorkeling) , Scuba diving); agricultural house constituent materials (eg, plastic sheets, plastic films, window glass); etc. Above all, it is suitable as glass for vehicles. For example, when used as vehicle glass, it is preferable to provide an anti-fog layer at least inside the vehicle.

The transparent material of the present invention utilizes the water-absorbing function of the cured product of the modified polyvinyl alcohol resin (A) contained in the anti-fog layer to generate fogging caused by the moisture existing on the anti-fog layer of the transparent material. Can be removed or reduced. Further, the moisture contained in the anti-fog layer can be easily removed from the anti-fog layer by drying. As a result, the transparent material of the present invention can exhibit anti-fog performance by repeating water absorption and drying.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. Unless otherwise specified, "%" and "parts" in Examples and Comparative Examples represent "% by mass" and "parts by mass", respectively.

(Calculation of denaturation rate)
Using a nuclear magnetic resonance apparatus "LAMBDA 500" manufactured by JEOL Ltd., ¹ H-NMR of the modified polyvinyl alcohol resin obtained in Synthesis Examples 1 to 8 was measured at room temperature, and a peak derived from an olefin proton (5.0) was measured. The modification rate was calculated from the integrated value of (~ 7.5 ppm). For example, in Synthesis Example 1 described later, the denaturation rate was calculated from the integrated values of the peaks derived from olefin protons appearing at 5.6 ppm and 6.0 ppm.

(Film thickness)
The thickness of the transparent base material, which is a transparent material before the anti-fog layer was provided, was measured at any five locations, and the average value was calculated. Next, the thickness of the transparent material after the anti-fog layer was provided was measured at any five locations, and the average value was calculated. The difference between the average values was taken as the film thickness.

(Anti-fog)
The transparent material was placed on a beaker containing warm water maintained at 40 ° C. so that the anti-fog layer was exposed to water vapor, and the time until fogging was visually measured.
A: It maintained ultra-transparency for 200 seconds.
B: Cloudiness occurred in more than 100 seconds and less than 200 seconds.
C: Cloudiness occurred in 100 seconds or less.

(Scratch resistance)
A dry cloth (Kanakin No. 3) is attached to a flat surface friction tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.), and 100 times at 60 reciprocations / minute while applying a load of 2.5 kg / cm2 on the surface of the transparent material on the anti-fog layer side. After reciprocating, the appearance of the film surface on the anti-fog layer side was visually observed and evaluated according to the following criteria.
A: There was no change in appearance.
B: Whitening occurred due to clear scratches.
C: In addition to whitening due to clear scratches, the anti-fog layer was peeled off.

(water resistant)
The transparent material was visually observed for changes in appearance after being immersed in boiling water for 1 hour, and evaluated according to the following criteria.
A: There was no change in appearance.
B: Film surface unevenness occurred due to excessive swelling of the anti-fog layer.
C: In addition to the unevenness of the film surface due to excessive swelling of the anti-fog layer, disintegration due to peeling or elution of the anti-fog layer occurred.

(Synthesis Example 1)
In a reactor equipped with a stirrer, a recirculation tube and an addition port, 510.3 parts by mass of methacrylic acid, 24.0 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. 8.1 parts by mass of toluene sulfonic acid monohydrate was sequentially charged, and 100 parts by mass of a commercially available polyvinyl alcohol resin (viscosity average polymerization degree 1700, saponification degree 95 mol%) was added while stirring at room temperature, while stirring. The temperature was raised to 65 ° C., and the reaction was carried out in a slurry state for 1 hour. Then, the mixture is cooled to room temperature, the contents are filtered to recover the modified polyvinyl alcohol resin, washed with a large amount of methanol, and then dried at 1.3 Pa at 40 ° C. for 20 hours to obtain the modified polyvinyl alcohol resin “PVOH”. -1 "was obtained. The evaluation results of the obtained "PVOH-1" are shown in Table 1.

(Synthesis Example 2)
In a reactor equipped with a stirrer, a recirculation 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 toluene sulfonic acid monohydrate was sequentially charged, and 100 parts by mass of a commercially available polyvinyl alcohol resin (viscosity average polymerization degree 300, saponification degree 82 mol%) was added while stirring at room temperature, while stirring. The temperature was raised to 65 ° C., and the reaction was carried out in a slurry state for 2.8 hours. Then, the mixture is cooled to room temperature, the contents are filtered to recover the modified polyvinyl alcohol resin, washed with a large amount of methanol, and then dried at 1.3 Pa at 40 ° C. for 20 hours to obtain the modified polyvinyl alcohol resin “PVOH”. -2 "was obtained. The evaluation results of the obtained "PVOH-2" are shown in Table 1.

(Synthesis Example 3)
In a reactor equipped with a stirrer, a reflux tube and an addition port, 510.3 parts by mass of 4-pentenoic acid, 56.7 parts by mass of ion-exchanged water, 1.3 parts by mass of p-methoxyphenol, and one water of paratoluenesulfonic acid. Add 4.2 parts by mass of Japanese product in sequence, add 100 parts by mass of a commercially available polyvinyl alcohol resin (viscosity average polymerization degree 1700, saponification degree 98.5 mol%) while stirring at room temperature, and stir to 60 ° C. The temperature was raised and the reaction was carried out in a slurry state for 3 hours. Then, the mixture is cooled to room temperature, the contents are filtered to recover the modified polyvinyl alcohol resin, washed with a large amount of methanol, and then dried at 1.3 Pa at 40 ° C. for 20 hours to obtain the modified polyvinyl alcohol resin “PVOH”. -3 "was obtained. The evaluation results of the obtained "PVOH-3" are shown in Table 1.

(Synthesis Example 4)
In a reactor equipped with a stirrer, a recirculation tube and an addition port, 454.2 parts by mass of methacrylic acid, 5.7 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 toluene sulfonic acid monohydrate was sequentially charged, and 100 parts by mass of a commercially available polyvinyl alcohol resin (viscosity average polymerization degree 1700, saponification degree 98.5 mol%) was added while stirring at room temperature, and the mixture was stirred. While doing so, the temperature was raised to 90 ° C., and the reaction was carried out in a slurry state for 3 hours. Then, the mixture is cooled to room temperature, the contents are filtered to recover the modified polyvinyl alcohol resin, washed with a large amount of methanol, and then dried at 1.3 Pa at 40 ° C. for 20 hours to obtain the modified polyvinyl alcohol resin “PVOH”. -4 "was obtained. The evaluation results of the obtained "PVOH-4" are shown in Table 1.

(Synthesis Example 5)
In a reactor equipped with a stirrer, a recirculation tube and an addition port, 454.2 parts by mass of methacrylic acid, 5.7 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 toluene sulfonic acid monohydrate was sequentially charged, and 100 parts by mass of a commercially available polyvinyl alcohol resin (viscosity average polymerization degree 2400, saponification degree 98.5 mol%) was added while stirring at room temperature, and the mixture was stirred. While doing so, the temperature was raised to 90 ° C., and the reaction was carried out in a slurry state for 10 hours. Then, the mixture is cooled to room temperature, the contents are filtered to recover the modified polyvinyl alcohol resin, washed with a large amount of methanol, and then dried at 1.3 Pa at 40 ° C. for 20 hours to obtain the modified polyvinyl alcohol resin “PVOH”. -5 "was obtained. The evaluation results of the obtained "PVOH-5] are shown in Table 1.

(Synthesis Example 6)
In a reactor equipped with a stirrer, a recirculation tube and an addition port, 499.0 parts by mass of methacrylic acid, 39,7 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. 3.4 parts by mass of toluene sulfonic acid monohydrate was sequentially charged, and 100 parts by mass of a commercially available polyvinyl alcohol resin (viscosity average polymerization degree 2400, saponification degree 88 mol%) was added while stirring at room temperature, while stirring. The temperature was raised to 75 ° C., and the reaction was carried out in a slurry state for 2.5 hours. Then, the mixture is cooled to room temperature, the contents are filtered to recover the modified polyvinyl alcohol resin, washed with a large amount of methanol, and then dried at 1.3 Pa at 40 ° C. for 20 hours to obtain the modified polyvinyl alcohol resin “PVOH”. -6 "was obtained. The evaluation results of the obtained "PVOH-6] are shown in Table 1.

(Synthesis Example 7)
In a reactor equipped with a stirrer, a recirculation tube, and an addition port, 493.3 parts by mass of acrylic 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 toluene sulfonic acid monohydrate was sequentially charged, and 100 parts by mass of a commercially available polyvinyl alcohol resin (viscosity polymerization degree 1700, saponification degree 98.5 mol%) was added while stirring at room temperature, and the mixture was stirred. While the temperature was raised to 65 ° C., the reaction was carried out in a slurry state for 10 hours. Then, the mixture is cooled to room temperature, the contents are filtered to recover the modified polyvinyl alcohol resin, washed with a large amount of methanol, and then dried at 40 ° C. and 1.3 Pa for 20 hours to obtain the modified polyvinyl alcohol resin "PVOH-". 7 ”was obtained. The evaluation results of the obtained "PVOH-7" are shown in Table 1.

(Synthesis Example 8)
In a reactor equipped with a stirrer, a recirculation tube and an addition port, 454.2 parts by mass of methacrylic acid, 5.7 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 toluene sulfonic acid monohydrate was sequentially charged, and 100 parts by mass of a commercially available polyvinyl alcohol resin (viscosity average polymerization degree 500, saponification degree 98.5 mol%) was added while stirring at room temperature, and the mixture was stirred. While doing so, the temperature was raised to 90 ° C., and the reaction was carried out in a slurry state for 5 hours. Then, the mixture is cooled to room temperature, the contents are filtered to recover the modified polyvinyl alcohol resin, washed with a large amount of methanol, and then dried at 1.3 Pa at 40 ° C. for 20 hours to obtain the modified polyvinyl alcohol resin “PVOH”. -8 "was obtained. The evaluation results of the obtained "PVOH-8" are shown in Table 1.

(Synthesis Example 9)
To a reactor equipped with a stirrer, a reflux tube and an addition port, 30 parts by mass of a commercially available polyvinyl alcohol resin (viscosity average degree of polymerization 500, saponification degree 98.5 mol%) and 100 parts by mass of ion-exchanged water were added, and the temperature was 90 ° C. The mixture was heated and stirred with and completely dissolved. After cooling to 30 ° C., 15 parts by mass of a 20% aqueous hydrochloric acid solution was added, and 7 parts by mass of benzaldehyde was added dropwise thereto. After dropping the whole amount over 1 hour, the temperature was raised to 60 ° C. and the reaction was carried out at 60 ° C. for 2 hours. As the reaction proceeded, the system became cloudy and precipitates were formed. After the reaction, after cooling to room temperature, a predetermined amount of sodium hydroxide aqueous solution was added to neutralize hydrochloric acid, the produced resin was isolated, washed with a large amount of cold water, and then washed at 40 ° C. at 1.3 Pa for 20 hours. By drying, a polyvinyl acetal resin "PVOH-C1" modified with benzaldehyde was obtained. As a result of analyzing "PVOH-C1" by ¹ H-NMR, the degree of acetalization was 9 mol%. The evaluation results are shown in Table 1.

(Examples 1 to 2, 4 to 8 and Comparative Examples 3 to 4)
Each PVOH obtained in the synthesis example was added to water and heated and stirred at 80 ° C. for 2 hours to obtain an aqueous solution having a concentration of 5%. The following materials were added to the obtained aqueous solution and mixed so as to have the composition shown in Table 2. To the obtained mixed liquid, 69% nitric acid was added so as to be 1% by mass with respect to TEOS, and the mixture was stirred until it became uniform at room temperature to prepare a coating liquid for forming an anti-fog layer.

For example, in Example 1, with respect to 40 parts by mass of an aqueous solution having a concentration of PVOH-1 of 5%.
0.02 parts by mass of photopolymerization initiator, 5.73 parts by mass of dispersion containing metal oxide component (B1), 3.43 parts by mass of hydrolyzable silicon compound (B'2), hydrolyzable titanium 0.57 parts by mass of a dispersion containing the compound (B'3) was added.

<Additional material>
Photopolymerization Initiator: 2-Hydroxy-4'-(2-Hydroxyethoxy) -2-methylpropiophenone Dispersion containing metal oxide component (B1): Colloidal silica (Nissan Chemical Industry Co., Ltd. Colloidal silica "Snow" TEX ST-C ”, an aqueous dispersion with a silica content of 20% by mass)
Hydrolyzable Silicon Compound (B'2): Tetraethoxysilane (hereinafter referred to as TEOS, "KBE-04" manufactured by Shin-Etsu Chemical Co., Ltd.)
Dispersion containing hydrolyzable titanium compound (B'3): Titanium lactate (“Organix TC-310” manufactured by Matsumoto Fine Chemical Co., Ltd., water / isopropanol dispersion with a titanium lactate content of 44% by mass)

Next, the coating liquid was bar-coated on the washed float plate glass (soda lime silicate glass, thickness 3.1 mm, size 100 × 100 mm). Then, after irradiating with ultraviolet rays at an intensity of 3000 mJ / cm ² for cross-linking treatment, hot air drying was carried out at 80 ° C., and further heat treatment was carried out at 120 ° C. to obtain a desired transparent material. The evaluation results are shown in Table 2.

(Example 3)
The coating liquid was adjusted as shown in Table 2, and the desired transparent material was obtained in the same manner as in Examples 1 to 8 except that the ^{coating liquid was irradiated with ultraviolet rays at an intensity of 10000 mJ / cm 2.} The evaluation results are shown in Table 2.

(Example 9)
As shown in Table 2, the coating liquid is adjusted, the coating liquid containing no photopolymerization initiator is bar-coated, dried with hot air at 80 ° C., and then 30 kGy electron beam (EB) instead of ultraviolet rays. ) Was irradiated, and the desired transparent material was obtained in the same manner as in Examples 1 to 8. The evaluation results are shown in Table 2.

(Example 10)
As the photopolymerization initiator, potassium persulfate was used instead of 2-hydroxy-4'-(2-hydroxyethoxy) -2-methylpropiophenone, and the coating liquid was prepared as shown in Table 2. The desired transparent material was obtained in the same manner as in Examples 1 to 8 except that the heat treatment was applied in a hot air dryer at 120 ° C. for 10 minutes instead of the ultraviolet irradiation step. The evaluation results are shown in Table 2.

(Comparative Example 1)
Float glass without anti-fog layer was evaluated. The evaluation results are shown in Table 2. Since Comparative Example 1 does not have an anti-fog layer, the anti-fog property and the scratch resistance were evaluated on the glass surface.

(Comparative Example 2)
As the modified polyvinyl alcohol resin, the target transparent material was used in the same manner as in Example 2 except that a commercially available polyvinyl alcohol resin (viscosity average degree of polymerization 1700, saponification degree 98.5 mol%) was used as it was as [non-modified PVOH]. Got The evaluation results are shown in Table 2.

As shown in Table 2, all of the transparent materials produced in Examples 1 to 10 are excellent in anti-fog resistance, scratch resistance, and water resistance. As shown in Comparative Example 1, the transparent material without the anti-fog layer causes fogging immediately when exposed to water vapor. When a non-denatured polyvinyl alcohol resin is used as in Comparative Example 2, the anti-fog layer has high water absorption, so that the anti-fog performance is excellent, but the water resistance is not exhibited. In addition, the scratch resistance was also inferior to that of the examples. When polyvinyl acetal is used as in Comparative Example 3, the resin itself has no crosslinkability and is therefore inferior in water resistance. When the modified polyvinyl alcohol resin alone does not have a metal oxide component as in Comparative Example 4, it is excellent in anti-fog property and water resistance, but inferior in scratch resistance.

According to the present invention, it is possible to provide a transparent material that not only has excellent anti-fog performance and anti-fog durability, but also exhibits excellent durability in exposure tests assuming various usage environments. The transparent material is particularly useful as vehicle glass.

Claims (10)

A transparent base material and an anti-fog layer formed on the base material are provided.
The antifogging layer is a layer formed from a cured product of a crosslinkable composition containing a modified polyvinyl alcohol resin (A) having an ethylenically unsaturated group in the side chain and a metal oxide component (B), and the crosslinking is performed. A transparent material in which the content of the modified polyvinyl alcohol resin (A) contained in the sex composition is 30% by mass or more. The transparent material according to claim 1, 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 independently hydrogen atoms, methyl groups, carboxyl groups or carboxymethyl groups, respectively, and X is an oxygen atom or -N (R ⁴ )-. There, R ⁴ is a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, * represents a bond of the ethylenically unsaturated group) The transparent material according to claim 1 or 2, wherein the modified polyvinyl alcohol resin (A) contains a structural unit represented by the following formula (II) or (III).

(In formula (II), R ¹ , R ² and R ³ are independently hydrogen atoms, methyl groups, carboxyl groups or carboxymethyl groups, respectively, and X is an oxygen atom or -N (R ⁴ )-. Yes, 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 * represents the modification. It is a bond of structural units in the polyvinyl alcohol resin (A))

(In the formula (III), R ¹ , R ² and R ³ are independently hydrogen atoms, methyl groups, carboxyl groups or carboxymethyl groups, respectively, and * is a structural unit in the modified polyvinyl alcohol resin (A). Is a bond) The transparent material according to any one of claims 1 to 3, wherein the modified polyvinyl alcohol resin (A) contains the partial structure represented by the formula (I) in a proportion of 0.2 to 5 mol%. The transparent material according to any one of claims 1 to 4, wherein the crosslinkable composition contains 5 to 100 parts by mass of the metal oxide component (B) with respect to 100 parts by mass of the modified polyvinyl alcohol resin (A). .. The transparent material according to any one of claims 1 to 5, wherein at least one of the metal oxide components (B) is an oxide component of Si. The transparent material according to any one of claims 1 to 6, wherein the anti-fog layer has a film thickness of 1 to 50 μm. The transparent material according to any one of claims 1 to 7, wherein the transparent base material is glass. The transparent material according to claim 8, wherein the glass is vehicle glass. A method for producing a transparent material comprising a transparent base material and an anti-fog layer formed on the base material.
A step of applying a coating liquid containing a crosslinkable composition containing a modified polyvinyl alcohol resin (A) having an ethylenically unsaturated group in the side chain and a metal oxide component (B) onto a transparent substrate and then curing the mixture. Including
A method in which the content of the modified polyvinyl alcohol resin (A) contained in the crosslinkable composition is 30% by mass or more.