JP2851420B2 - Anti-fog sheet and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sheet having an antifogging property and a method for producing the same, and particularly to an antifogging property having a good surface condition and excellent durability for holding the antifogging sheet for a long period of time. The present invention relates to a sheet and a method for manufacturing the sheet.

BACKGROUND ART When exposed to moisture, the surfaces of automobile windows and side mirrors, bath mirrors and windows become cloudy,
It was inconvenient, such as frequent wiping. Therefore, various attempts have been made to impart antifogging properties to the surface of these articles.

Conventionally, as an anti-fogging layer that imparts anti-fogging property to the surface of an article, (a) those that have obtained anti-fogging properties by kneading a surfactant into a resin, (ii) inorganic salts such as colloidal silica and phosphite And (3) those whose surfaces have been made hydrophilic by modifying polymers such as saponification of acetylcellulose.

However, the antifogging layers (a) and (b) have a problem that the antifogging life is short due to leaching of a surfactant. Furthermore, the antifogging layer (c) has poor film strength when wet,
There is a problem that the antifogging property is deteriorated due to damage during the application.

As a solution to the above problems of the prior art, the present inventors have previously provided a support film and an anti-fog layer, and the anti-fog layer is obtained by crosslinking a polymer and a hydrophilic monomer by electron beam irradiation. (JP-A-63-273668, JP-A-63-251401, and JP-A-63-251401).
-258905, 63-258904, 63-278840).

Recently, there has been a need for an antifogging sheet having a relatively thick antifogging layer (hydrophilic film). This is because there has been a demand for further improving the anti-fogging property and maintaining the anti-fogging property for a long period of time. However, when an attempt is made to form a thick antifogging layer with a solvent-containing coating solution, the problem of residual solvent and the surface of the antifogging layer become rough, which makes the antifogging sheet unsuitable for application to mirrors and windows. I understand.

DISCLOSURE OF THE INVENTION Accordingly, an object of the present invention is to provide an antifogging sheet having a thick hydrophilic film for maintaining the antifogging property for a long time, and a method for producing the same.

In light of the above objects, as a result of intensive studies, the present inventors have applied a composition for a hydrophilic film having a specific composition and viscosity as a non-solvent-based coating solution on a support film by a specific method, and ionized radiation. It has been found that a thick hydrophilic film having a favorable surface condition can be obtained by crosslinking by irradiation.

That is, the method for producing an antifogging sheet according to the present invention is a method for producing a thick film type antifogging sheet having a thickness of 30 μm or more, wherein (a) a polymer and (b) a hydrophilic monomer are contained as essential components. And (c) preparing a composition containing a surfactant, having a viscosity of 50,000 centipoise or less and containing no solvent, applying the composition to a support film surface without using a solvent, The composition is cross-linked by irradiation with ionizing radiation to form a hydrophilic film having a thickness of 30 μm or more.

In a preferred embodiment of the present invention, in applying the composition to a support film and forming a hydrophilic film, a support film and a film for lamination are prepared, and these films are placed between a pair of rolls. By stacking and disposing the composition while supplying and pressing the composition between the two films, a layer of the composition is formed between the two films, and the pressing force when pressing the two films with a roll. Extruding an excess amount of the composition supplied by the above-described manner, so that a pool of the composition is formed at the boundary between the two films at the gap entrance of the roll, thereby forming the composition formed between the two films. In order to prevent gas from being mixed into the layer, the obtained support film / composition / laminate film comprising Thickness by crosslinking the composition of the laminated body by irradiating the ionizing radiation of 30
It is preferable to form a hydrophilic film on the surface of the support film by forming a hydrophilic film having a thickness of not less than μm and peeling the laminating film from the laminate.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 3 are schematic views each showing a laminating method that can be used in producing an antifogging sheet according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

As the support film, various materials can be used depending on the use as long as the support film has sufficient mechanical strength and transparency to support the hydrophilic film. Specific examples include films of polyesters such as polyethylene terephthalate, polyolefins such as polyethylene and polypropylene, polyamides such as nylon, and synthetic resins such as polycarbonate, polyacrylate, polystyrene, and polyvinyl chloride. These can be laminated and used as needed.

The support film may be colored in various colors as needed. As the colorant, a disperse dye is preferable, and disperse dyes such as monoazo, bisazo, anthraquinone, nitro, styryl, methine, alylene, benzimidazole, aminonaphthylamide, nactquinone imide, and coumarin derivative can be used.

The hydrophilic film in the present invention is basically composed of a polymer obtained by crosslinking a composition containing a hydrophilic monomer and a surfactant. The specific composition of the composition is as follows: (a) polymer + hydrophilic monomer + surfactant; (b) polymer + hydrophilic monomer + crosslinkable monomer +
(C) Polymer + hydrophilic cross-linkable monomer + surfactant, (d) polymer + hydrophilic monomer + hydrophilic cross-linkable monomer + surfactant. In all of the above combinations, the polymer may be either a functional polymer or a non-functional polymer.

Non-functional polymers include polyacrylic acid alkyl ester, polymethacrylic acid alkyl ester, polyurethane, polyester, polyamide, polyvinyl acetate, polyvinyl chloride, polystyrene, polyacrylonitrile,
Polyvinylpyrrolidone and the like can be used.

A hydrophilic group may be previously introduced into the non-functional polymer in order to improve the compatibility with the hydrophilic monomer. This is a copolymer with a monomer having a hydrophilic group (hydrophilic monomer) described later. The ratio of the hydrophilic monomer to the non-functional polymer is 50 mol% or less, and when it exceeds this, the water resistance of the obtained film is reduced.

Furthermore, partially saponified polyvinyl alcohol, polyvinyl butyral, polyvinyl alcohol derivatives such as polyvinyl acetal, and cellulose derivatives such as nitrocellulose, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, and hydroxypropyl cellulose can also be used. .

On the other hand, the functional polymer is a polymer having a functional group that causes a crosslinking reaction by ionizing radiation, and examples of the functional group include the following.

The ratio of the functional group is desirably one in the molecular weight of 300 to 10,000 of the polymer. When the ratio is less than one per 10,000 molecular weight, there is almost no crosslinking effect by the functional group, and when the ratio exceeds one per 300 molecular weight, the crosslink density is higher. Is too high.

Examples of the functional polymer include urethane acrylate, polyester acrylate, epoxy acrylate and the like, and acrylic acid chloride or 2-hydroxyethyl acrylate and diisoianate at the hydroxyl group of a copolymer of acrylic acid acrylate and 2-hydroxyethyl acrylate. : 1 copolymers by introducing an acryloyl group by adding an adduct, a copolymer in which glycidyl methacrylate is added to a carboxyl group of a copolymer of acrylic acid alkyl ester and acrylic acid, and a residual hydroxyl group of polyvinyl butyral Acrylic acid chloride or acrylic acid-2
A product obtained by adding a 1: 1 adduct of -hydroxyethyl and diisocyanate can be used.

The polymer may be in the form of an oligomer, but preferably has a molecular weight of 1,000 to 300,000 (weight average) from the viewpoint of film forming properties.

The hydrophilic monomer is a monomer containing a hydrophilic group such as a hydroxyl group, a carboxyl group (metal salt), an amide group, an imide group, a sulfone group, an ammonium base, and a phosphoric acid group. For example, 2-hydroxyethyl acrylate, methacrylic acid 2-hydroxyethyl, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, acrylic acid, methacrylic acid, metal acrylate, metal methacrylate, dimer acrylate, acrylamide, methacrylamide, dimethylaminopropylacrylamide, dimethyl Aminopropyl methacrylamide, N-acryloyl morpholine, N-methacryloyl monophorin, N-methylol acrylamide, N-methylol methacrylamide, t-butyl acrylamide, t-butyl methacrylamide, N- Butoxy methyl acrylamide, N- ethoxymethyl acrylamide, N-n-butoxy acrylamide, N, N- dimethylacrylamide, N, N- dimethylaminopropyl acrylamide, N, N
-Dimethylaminopropyl methacrylamide, polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, glycerol monomethacrylate, 2-acrylamide 2-methylpropanesulfonic acid, methacrylamidopropyltrimethylammonium chloride, methacryloyloxyethyltrimethylammonium chloride, mono (2-methacrylate) (Chloroylethyl) acid phosphate and the like.

The crosslinkable monomer is a monomer having two or more groups that easily become a radical by electron beam irradiation such as an acryloyl group, a methacryloyl group, an allyl group, and an epoxy group, and is cross-linked to any of the skeleton polymer and the hydrophilic monomer. The crosslink density of the entire film is improved, the film strength is increased, and unreacted hydrophilic monomers are not left. Examples of such a crosslinking monomer include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, glycidyl methacrylate, neopentyl glycol dimethacrylate, tetraethylene glycol dimethacrylate, and 2,2-bis [4 -(Acryloxydiethoxy) phenyl] propane, 2,2-bis [4- (methacryloxydiethoxy) phenyl] propane, 2,2-bis [4-
(Acryloxypolyethoxy) phenyl] propane, 2,
Bifunctional monomers such as 2-bis [4- (methacryloxypolyethoxy) phenyl] propane, trifunctional monomers such as trimethylolpropane olimethacrylate, and other polyfunctional monomers such as tetramethylol methane tetraacrylate and dipentaerythritol hexaacrylate Is mentioned.

Hydrophilic crosslinkable monomers include hydroxyl groups, carboxyl groups (metal salts), amide groups, imide groups, sulfonic acid groups (metal salts), ammonium groups, phosphoric acid groups and other hydrophilic groups and acryloyl groups, methacryloyl groups, allyl groups, A monomer having two or more crosslinkable functional groups that easily become radicals upon irradiation with an electron beam such as an epoxy group.

Examples of such a hydrophilic crosslinkable monomer include, for example,
Those having a hydroxyl group such as glycerol di (meth) acrylate and glycerol methacrylate acrylate, ethylene glycol, diglycidyl ether di (meth) acrylate, polyethylene glycol / diglycidyl ether di (meth) acrylate, and polypropylene glycol / diglycidyl ether di (meth) ) Acrylate,
Diols such as neopentyl glycol diglycidyl ether di (meth) acrylate, glycerin diglycidyl ether di (meth) acrylate, bisphenol A diglycidyl ether di (meth) acrylate, and trimethylolpropane triglycidyl ether di (meth) acrylate 1: with glycidyl ether and acrylic acid
2 adducts, pentaerythritol mono (meth) acrylate, pentaerythritol di (meth) acrylate,
Pentaerythritol tri (meth) acrylate, dipentaerythritol mono (meth) acrylate, dipentaerythritol di (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) A) pentaerythritol derivatives such as acrylate, methylenebis (meth) acrylamide, acrylamide / glyoxal adduct, acrylamide / methyloethylene urea condensate, 1,3,5-triacryloylhexahydros-triazine, N, N-diallylacrylamide, acrylamide, Methylol melamine condensate, acrylamide / methylol triazone condensate, acrylamide / methylol hydantoin condensate,
There are acrylamide derivatives such as acrylamide / methylol urea and N, N-diallylacrylamide.

The hydrophilic film used in the present invention also contains a surfactant. Surfactants have an effect of imparting anti-fogging properties (anti-condensation properties) by gradually exuding from the hydrophilic film to the surface. Further, the surfactant has an action of keeping the hydrophilic monomer in a favorable state in the coating film. Any of anionic, nonionic and cationic surfactants can be used as long as they have good compatibility with the composition comprising the above components constituting the hydrophilic layer.

Examples of anionic surfactants include fatty acid salts, alkyl sulfate salts, alkyl benzene sulfonates, alkyl naphthalene sulfonates, dialkyl sulfosuccinate esters, alkyl phosphate esters, naphthalene sulfonic acid-formalin condensates, and polyoxyethylene. Alkyl sulfates, etc., and nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylamine Glycerin fatty acid esters, oxyethylene-oxypropylene block polymers, etc., and cationic surfactants include alkylamines and quaternary ammonium. There is salt, and the like.

When forming the hydrophilic film used in the present invention, the polymer 10
It is preferable to add the hydrophilic monomer in a ratio of 5 to 400 parts by weight per 0 parts by weight. If the amount is less than 5 parts by weight, sufficient hydrophilicity will not be imparted, and if it exceeds 400 parts by weight, the water resistance of the film will decrease. Preferred hydrophilic monomer content is 50 to
300 parts by weight.

The crosslinking monomer is used in an amount of 1 to 300 parts by weight per 100 parts by weight of the polymer. When the amount is less than 1 part by weight, the unreacted hydrophilic monomer is insufficiently crosslinked, and when it exceeds 300 parts by weight, the crosslink density of the whole film becomes too high. Particularly when the polymer has no functional group, the content of the crosslinkable monomer is preferably from 5 to 300 parts by weight, more preferably from 5 to 200 parts by weight. When the polymer has a functional group, the content of the crosslinkable monomer is preferably 1 to 200 parts by weight, more preferably 5 to 100 parts by weight.

The amount of the hydrophilic crosslinkable monomer is 1 per 100 parts by weight of the polymer.
~ 200 parts by weight. If the amount is less than 1 part by weight, sufficient hydrophilicity and crosslinking property cannot be imparted, and if it exceeds 200 parts by weight, the crosslinking density becomes too high. The preferred content of the hydrophilic crosslinkable monomer is 1 to 100 parts by weight.

The surfactant is preferably used in an amount of 200 parts by weight or less per 100 parts by weight of the polymer. If the amount exceeds 200 parts by weight, the crosslinking becomes insufficient and the surfactant oozes out too much. A more preferred content is 1 to 100 parts by weight. In the case of curing by ultraviolet irradiation, sensitizers such as benzoquinone, benzoin, benzoin ethers such as benzoin methyl ether, halogenated acetone phenones,
Biacetyls and the like that generate radicals by ultraviolet irradiation can also be used.

When a hydrophilic film is formed, it is important that a composition comprising an appropriate combination of the above components be used as a coating solution without adding a solvent. According to the findings of the present inventors, when the hydrophilic film is 30 μm or less, a good surface state can be obtained even with a solvent-containing coating liquid, but when the thickness is more than 30 μm, the obtained surface state rapidly deteriorates. I do. Also, not using any solvent is advantageous in terms of simplification of the manufacturing process, safety, and environmental issues.

Using the above composition, a hydrophilic film can be formed into a support film by the following method.

First, a solvent-free composition is adjusted to an appropriate viscosity by a method such as heating, and applied on a support film by a roll coating method such as a gravure reverse method, a three-ribose method, a gravure direct method, or a four-reverse method. I do.

When the composition is applied to a support film and, for example, is to be mirror-finished, a mirror-like film is laminated thereon, followed by irradiation with ionizing radiation.

Next, a case where a hydrophilic film is formed by the above-described lamination method will be described.

As a method for efficiently producing a thick film type antifogging sheet as in the present invention, a method using a laminating method is excellent. In this method, in performing the application of the above-described composition to a support film and the formation of a hydrophilic film, a support film and a film for lamination are prepared, and these films are arranged so as to overlap between a pair of rolls. By supplying the composition between the two films and transferring while pressing, a layer of the composition was formed between the two films, and supplied by the pressing force when the two films were pressed by a roll. Extruding an excess amount of the composition causes a pool of the composition to be formed at the boundary between the films at the gap entrance of the roll, thereby forming a gas layer in the composition layer formed between the films. And ionizing radiation is applied to the laminate comprising the support film / composition / laminate film obtained. Forming a hydrophilic film on the surface of the support film by crosslinking the composition in the laminate to form a hydrophilic film having a thickness of 30 μm or more, and peeling the laminating film from the laminate. Features.

In general, when laminating films, a method is used in which an amount of the composition necessary for lamination is applied to at least one of the films in advance, and the film is pressure-bonded in a gap between rolls such as a nip roll.

However, this method has a problem that bubbles are easily mixed into the coating layer when the surface of the coated coating liquid is uneven or when the coating liquid is thickened and laminated.

If the coating layer is mixed with air, not only will it not be able to perform adequately, but it will cause poor appearance and blisters, etc. In addition, when the coating layer is cured after lamination, the air acts as a reaction inhibitor, Problems such as insufficient curing of the layer (hydrophilic film) occur.

The present inventors have found that when pressing a pair of films in which a coating solution composed of a composition for a hydrophilic film is interposed in an amount larger than an amount necessary to obtain a target film thickness, extra pressure is applied by the pressing force. It has been found that if a pool of the coating liquid is formed by extruding a suitable ink, the incorporation of bubbles and the like can be effectively prevented.

FIG. 1 is a schematic view showing the above laminating method.

The apparatus shown in FIG. 1 has a pair of nip rolls 1 and 2, a coating roll 3, and a paint grain 5 containing a coating liquid 4.

In such an apparatus, one film, for example, the base film 6 passes between the nip roll 1 and the coating roll 3 and is fed to the gap between the nip rolls 1 and 2. At this time, since the surface of the coating roll 3 is coated with the coating liquid 4 in the coating liquid 5, the support film 6 reaches the entrance of the gap between the nip rolls 1 and 2 after the coating liquid 4 is applied. Will be.

Here, the supporting film 6 by the coating roll 3
The gap between the coating roll 3 and the nip roll 1 is adjusted so that the amount of the coating liquid 4 applied to the coating layer is larger than the amount of the coating liquid necessary for lamination.

On the other hand, the laminating film 7 is fed from the nip roll 2 side to the entrance of the gap.

The support film 6 and the laminating film 7 fed to the entrance of the gap are pressed by the nip rolls 1 and 2 to be laminated. At this time, since the coating liquid is applied in an amount larger than necessary to obtain the target film thickness, the excess ink is pushed out to the inlet of the gap by the pressing force, and the coating liquid is accumulated there. 8 are formed.

By forming the pool 8 in this manner, the contact surface between the support film 6 and the laminating film 7 is completely covered with the coating liquid during lamination. For this reason, lamination of both films can be performed without contacting with air, and the incorporation of air into the coating amount can be effectively prevented.

In addition, in the above example, since the pool 8 is provided below the roll gap portion, the coating liquid in the pool 8 may collect to a certain extent, as indicated by a broken arrow in FIG.
Drip. Therefore, if the excess ink is collected and reused, for example, the ink is received by the paint grain 5 as in the above example, it is advantageous in terms of economy.

The amount of the composition applied is adjusted by setting the gap between the nip rolls 1 and 2 according to the thickness of the support film 6 and the laminating film 7 and the ink used, so that the desired thickness of the hydrophilic layer is obtained. By doing so.

After laminating the support film 6 and the laminating film 7 as described above, the coating liquid is cured by a drying device or a curing means such as ultraviolet rays and electron beams, and the anti-fogging property is obtained by peeling off only the laminating film. You can get a sheet.

The laminating film 6 that can be used in the laminating method as described above is not particularly limited as long as it has sufficient mechanical strength to support the hydrophilic layer, and various materials may be used. it can. Specific examples include polyesters such as polyethylene terephthalate, polyethylene, polyolefins such as polypropylene, polyamides such as nylon, polycarbonate, polyacrylate, polystyrene, films of synthetic resins such as polyvinyl chloride, sheets, synthetic paper, natural paper and the like. .

In the case of curing by irradiation with ultraviolet rays, it is desirable to use a transparent film having good ultraviolet transmittance.

However, according to the findings of the present inventors, it is effective that the supporting film and the laminating film are made of the same material and effective in maintaining the antifogging property and the antifogging property over a long period of time. It is known. This is because, by using the same material, the surface energy characteristics of both layers become uniform, and thus the surfactant in the intervening hydrophilic film can be dispersed and maintained in a uniform and isotropic state. Conceivable. That is, the surfactant in the hydrophilic film has a function of capturing the hydrophilic monomer and retaining it in the film. In this case, if the surface energy characteristics of the two layers are different, they will be localized on the surface side of one of the films accordingly. According to the findings of the present inventors, such localization of the hydrophilic monomer (anisotropic state) is not preferable in terms of antifogging property development and its long-term retention performance.

When a hydrophilic film is formed by the above-described laminating method, the viscosity of the composition to be applied is also an important factor. In the above method, the viscosity of the coating solution is
It is preferably 50,000 centipoise or less. More preferably, it is 5000 centipoise or less. If the viscosity of the coating liquid exceeds 50,000 centipoise, the coating liquid will not be extruded well during lamination, and air will easily enter the coating layer.

Furthermore, in the present invention, the surface roughness of the obtained hydrophilic film is, as a center line average roughness, preferably 0.1 μm or less, more preferably 0.05 or less, more preferably
It is 0.01 μm or less.

In order to obtain a film having the above roughness, it is preferable to use a support film and a laminating film having a center line average roughness of 0.1 μm or less, more preferably 0.05 μm or less.

Although the laminating method has been described above with reference to FIG. 1, the present invention is not limited to this, and various changes can be made.

For example, toward the nip rolls 1 and 2, the support sheet 6
(The coating liquid has been applied.) And the laminating film 7 can also be fed from the side. For example, the second
As shown in the drawing, the support sheet 6 may be fed from above, and the laminating film 7 may be fed from the side.
In this case, the pool 8 is formed on the film 7 on the side of the gap. In this example, the support sheet 6 and the laminating film 7 may be exchanged.

In addition, as shown in FIG.
Support sheet 6 (coating liquid has been applied). Alternatively, the laminating film 7 may be fed from above and laminated, and then guided downward. In this case, the pool 8 is formed above the gap.

Next, a method for crosslinking the hydrophilic layer of the laminate obtained as described above will be described.

As described above, the curing of the hydrophilic layer is performed by irradiation with ionizing radiation such as an electron beam or ultraviolet light.

As an irradiation method, in the case of an electron beam, any method such as an electron curtain method and a beam scanning method can be used. The energy of the irradiated electron beam is about 150 to 200 keV, and the amount of irradiation varies depending on the formation of the composition, the desired degree of crosslinking density, and the like. The smaller the amount of irradiation, the higher the functional group in the polymer, and the higher the amount of irradiation as the crosslink density is increased. Particularly when a surfactant is contained, if the crosslinking density is too high, the bleeding becomes insufficient, and the antifogging (prevention of dew condensation) action is reduced.
Controlling the dose is important.

From the above, the irradiation dose is generally 0.5 to 20 Mrad,
Unreacted monomers of less than 0.5 Mrad may remain, and if it exceeds 20 Mrad, the crosslink density becomes too high.

In the case of ultraviolet irradiation, ultraviolet light emitted from an ultraviolet light source using a light source such as an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc, a metal halide lamp, and a black light lamp can be used.

After a hydrophilic film is formed by irradiation with an electron beam or ultraviolet rays, if a mirror surface film or the like is attached to the surface, it is peeled off. Further, the film on the surface can be used as a protective film without being peeled off until construction.

As described above, in the present invention, by forming a hydrophilic film using a non-solvent type coating solution, the surface condition can be improved even when the thickness is increased to 30 μm or more. Further, by irradiating an electron beam or an ultraviolet ray with the film adhered to the surface, the surface state can be further changed to a desired one such as a mirror surface.

Next, the invention will be described in more detail with reference to examples.
It goes without saying that the present invention is not limited to these.

Example 1 Using two separable flasks and a separable cover equipped with a heating and stirring device, isophorone diisocyanate 44 was used.
4 g was placed in a flask, and 0.2 g of dinormabutyltin dilaurate was added dropwise as a catalyst, followed by heating and stirring at 40 ° C. 650 g of butylene adipate ("Nipporan N-4570", manufactured by Nippon Polyurethane Co., Ltd.) was gradually added so that the temperature in the system did not suddenly increase, and the reaction was allowed to proceed. After 2 hours, 232 g of 2-hydroxyethyl acrylate was added dropwise and the reaction temperature was raised to 60
C. and the stirring was continued until the peak due to the isocyanate group at 2330 cm ^{-1 in} the IR spectrum disappeared. Thus, the urethane acrylate (I) can be obtained with a yield of almost 100%.
Generated.

To 100 parts by weight of the obtained urethane acrylate (I),
100 parts by weight of 2-hydroxyethyl methacrylate as a hydrophilic monomer, 10 parts by weight of neopentyl glycol diacrylate (NPGDA) as a crosslinking agent, and 5 parts by weight of Emulgen 106 (manufactured by Kao Corporation) as a surfactant are uniformly mixed, A coating solution was prepared. This was heated to adjust the viscosity to 500 cps, and applied to a 50 μm-thick easily treated polyester film (HP-7 manufactured by Teijin Limited) at a thickness of 50 μm by a roll coating method, and a 25 μm-thick polyester A film (Lumirror T type) was laminated by the method described above, and irradiated with 5Mard of an electron beam of 175 keV using an electron curtain type electron beam irradiation device (manufactured by BSI), and the coating film was cured. The center line average roughness of the obtained coating film surface is 0.005μ
m.

The antifogging property evaluation of the obtained antifogging sheet was performed by the following test.

(1) Inhalation test (checks whether or not fogging occurs due to inhalation) Test evaluation ○: No fogging ×: Fogging occurs (2) 50 ° C steam test (fogging occurs when a film is exposed to hot steam at 50 ° C) Test evaluation ◎: No fogging for 1 hour or more ○: No fogging for 3 minutes or more △: Fogging occurs in less than 3 minutes ×: Immediate fogging of the antifogging sheet obtained by the method according to this example The antifogging property was ○ in (1) and ◎ in (2).

Example 2 A urethane acrylate (II) was prepared in the same manner as in Example 1 except that 1000 g of carbonate diol ("Placcel CD-210", manufactured by Daicel Chemical Industries, Ltd.) was used instead of butylene adipate used in Example 1. ) Was synthesized.

100 parts by weight of the obtained urethane acrylate (II) were 100 parts by weight of glycerol monomethacrylate (GM) as a hydrophilic monomer, and Resistat SA-1 was used as a surfactant.
30 (manufactured by Daiichi Kogyo Chemical Co., Ltd.)
Thereafter, coating was performed in the same manner as in Example 1 to obtain an electron beam cured film having a thickness of 40 μm.

The antifogging properties of the obtained antifogging sheet were (1) ○, (2) ◎
Met.

Example 3 100 parts by weight of acrylic polymer, G as hydrophilic monomer
A coating solution comprising 200 parts by weight of M, 20 parts by weight of pentaerythritol acrylate (PETA) as a crosslinking agent, and 5 parts by weight of Exel O-95R (manufactured by Kao Corporation) as a surfactant was prepared.

The preparation of the coating solution was performed according to the following procedure. That is,
Methyl methacrylate 70 parts by weight, 2-hydroxyethyl methacrylate 39 parts by weight, azobisisobutyronitrile 0.15 parts by weight, methyl ethyl ketone 70 parts by weight equipped with a reflux tube and a stirrer, into a nitrogen-separable separable flask And reacted at 85 ° C. for 5 hours in a N ₂ stream. Thereafter, 0.15 parts by weight of azobisisobutyronitrile was further added and reacted for 3 hours. After the reaction, 218 parts by weight of GM, PETA 21.
8 parts by weight and 5.45 parts by weight of O-95R were added, and methyl ethyl ketone was removed while heating and stirring to obtain a desired coating solution.

The above coating solution was heated to adjust the viscosity to 1000 cps, and applied on a 50 μm-thick easily treated polyethylene terephthalate film (HP-7 manufactured by Teijin Limited) by a roll coating method,
After drying at 100 ° C., the laminate was laminated in the same manner as in Example 1, and then irradiated with an electron beam to cure the coating to a thickness of 50 μm.

The antifogging properties of the obtained antifogging sheet were (1) ○, (2)
◎

Examples 4 to 11 Using the compositions having the respective compositions shown in FIG. 1, antifogging sheets were prepared in the same manner as in Example 1, and the same test was performed. The results are also shown in Table 1.

Examples 12 to 15 Each of 100 parts by weight of the coating solution used in Examples 1 to 4 was mixed with 5 parts by weight of a photoinitiator [Irgacure 651]. 160w / c
m input) for 5 seconds.

Comparative Example 1 The composition of Example 8 was applied to a thickness of 3 μm, and the antifogging property was evaluated. As a result, (1) was ○ and (2) was Δ, and the antifogging performance was lower than that of Example 8. .

Comparative Example 2 The composition of Example 7 was applied to a thickness of 5 μm,
As a result of long-term evaluation of the steam evaluation at 50 ° C. in (2), at 5 μm pressure, the performance deteriorated (fogging occurred) in about 50 hours. On the other hand, with the film thickness of Example 7, no fogging occurred even after 100 hours.

As described above, in the antifogging sheet of the present invention, by increasing the thickness of the hydrophilic film, the absolute amount of moisture taken into the film can be increased, and the antifogging performance can be improved. In addition, since a surfactant as a long-term antifogging agent is added, it is advantageous in terms of maintaining antifogging properties.
In other words, since the absolute amount of the surfactant is larger in the thick film than in the thin film, when the outflow control of the surfactant by the electron beam irradiation is the same for the thick film and the thin film, the thick film has a longer anti-fogging effect. Sex can be maintained.

INDUSTRIAL APPLICABILITY The antifogging sheet according to the present invention can be applied to various uses as described below.

1) Eyeglass lenses: Prescription glasses, sunglasses, dustproof
Disaster prevention glasses, goggles, underwater glasses, etc.

2) Masks: Fire masks, agricultural work masks, diving masks, other safety masks, protective equipment, helmet shields, etc.

3) Mirrors: Interior mirror, bathroom mirror, road mirror, treatment mirror (dental mirror), automobile mirror, hand mirror, etc.

4) Instrument panels: Various detectors, measuring instruments, etc.

5) Glasses: architectural window glass, vehicle window glass, microwave oven glass, windshield of monitoring tower, refrigerated / refrigerated showcase, etc.

6) Plastics: Agricultural house, agricultural poly, greenhouse,
Lighting windows, food packaging films, etc.

7) Frost protection inside electrical appliances: Refrigerators, other home appliances, etc.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tomio Doi 1-1-1, Ichigaya Kagacho, Shinjuku-ku, Tokyo Inside Dai Nippon Printing Co., Ltd. (72) Inventor Masahiro Yamamoto 1-1-1, Ichigaga-cho, Shinjuku-ku, Tokyo No. 1 Within Dai Nippon Printing Co., Ltd. (56) References JP-A-63-278840 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B32B 1/00-35/00 B05D 1/00-7/26

Claims (8)

(57) [Claims] 1. A method for producing a thick film type antifogging sheet having a thickness of 30 μm or more, comprising as essential components (a) a polymer, (b) a hydrophilic monomer and (c) a surfactant. And, the viscosity is 50,000 centipoise or less, to prepare a composition that does not contain a solvent, the composition is applied to the surface of a support film without using a solvent, and the applied composition is further exposed to ionizing radiation. A method for producing an antifogging sheet, comprising forming a hydrophilic film having a thickness of 30 μm or more by crosslinking by irradiation. 2. The method of claim 1, wherein said composition further comprises a crosslinking monomer. 3. The method of claim 1, wherein said hydrophilic monomer comprises a crosslinkable monomer. 4. The method according to claim 1, wherein the ionizing radiation is an electron beam or ultraviolet light. 5. In applying the composition to a support film and forming a hydrophilic film, a support film and a film for lamination are prepared.
Placing both these films between a pair of rolls,
By supplying the composition between the two films and transferring while pressing, a layer of the composition is formed between the two films, and the composition supplied by the pressing force when the two films are pressed with a roll. By pushing out an excess amount of the material, a pool of the composition is formed at the boundary between the two films at the entrance of the gap of the roll, and thereby the gas is mixed into the layer of the composition formed between the two films. By irradiating the laminate comprising the obtained support film / composition / laminate film with ionizing radiation to cross-link the composition in the laminate to a thickness of 30 μm.
2. The method according to claim 1, wherein the film is a hydrophilic film having a thickness of at least m, and only the laminating film is separated from the laminate. 6. The method according to claim 5, wherein the support film and the laminating film have a center line average roughness of 0.1 μm or less. 7. An antifogging sheet obtained by the method according to claim 1. 8. An antifogging sheet obtained by the method according to claim 6.