JP2014117839A - Laminated antifogging film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated antifogging film which is composed of an antifogging composition layer (A) and a transparent support layer (B) and exerts antifogging performance, water resistant performance, adhesion performance, optical performance, mechanical strength and their persistency in an antifogging measure for e.g. window glasses, lenses, mirrors and optical sensors.SOLUTION: A laminated antifogging film consists of an antifogging composition layer (A) obtained by reacting a copolymer having isocyanate groups and obtained by copolymerization of an isocyanate ethyl(meth)acrylate, a specified N-substituted alkyl(meth)acrylamide and (meth)acrylate monomer with a polyol of a hydroxyl value of 150-650 mgKOH/g and having a water absorption characteristic of 1-100 g/mand a transparent support layer (B). The laminated antifogging film exerts higher antifogging performance owing to its excellent water absorption and also has excellent water resistant performance, adhesion performance, optical performance, mechanical strength and their persistency meeting practical requirements.

Description

The present invention relates to a functional laminated film provided with an antifogging coating having water absorption characteristics as a countermeasure against fogging in window glass, lenses, mirrors, optical sensors and the like. More specifically, the obtained laminated anti-fogging film is composed of an anti-fogging layer and a transparent support layer that are excellent in anti-fogging performance, water resistance performance, adhesion performance, optical performance, mechanical strength and their sustainability. The present invention relates to a laminated film.

Transparent synthetic resins and glasses represented by polymethacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polyvinyl chloride (PVC), etc. are excellent in transparency, moldability, and mechanical properties. It is used in many fields such as mirrors and optical sensors.

However, on the surface of synthetic resin molded products and glass, when the surface temperature falls below the dew point temperature, the moisture in the atmosphere is condensed as fine water droplets, resulting in cloudiness, thereby reducing light transmission. There is a problem in that it causes poor visibility and malfunction of the sensor. In order to prevent fogging that causes such problems, there has been proposed a technique for imparting antifogging performance by performing various treatments on the surface of a molded article or the like using synthetic resin or glass.

As a method for preventing such fogging, for example, (1) a method of applying a surfactant to the substrate surface (see Patent Document 1), (2) a coating containing a hydrophilic resin and a surfactant on the substrate surface There are a method of applying an agent (see Patent Document 2), a method (3) of forming a film having photocatalytic activity on the surface of a substrate (see Patent Document 3), and the like.

The method (1) is excellent in the initial antifogging property, but has a drawback that the applied anti-fogging agent is washed away by adhering water or rainwater and the antifogging effect is lost. Therefore, it is limited to applications that can be repeatedly applied such as agricultural vinyl sheets and eyeglass lenses. The method (2) expresses antifogging properties by the effect of the hydrophilic resin and the bleed effect of the surfactant, and has a relatively long antifogging effect, but in some cases, it is the same as (1) In some cases, the anti-fogging effect is lost due to washing away the surfactant and the water resistance of the hydrophilic resin is low, resulting in coating film defects. The method (3) is a film made of an inorganic substance such as titanium oxide, so it has excellent physical strength. However, ultraviolet light is necessary for the development of anti-fogging properties, and functions in all environments. is not.

On the other hand, in the antifogging treatments (1) to (3) represented by the above, all require a step of directly applying to a molded product. Therefore, installation (applying) requires paintable equipment, and the use is limited due to differences in molded products having various shapes and their materials.

In recent years, a method of applying an antifogging film having various antifogging functions including the above-described antifogging treatment method has been proposed. For example, a hygroscopic anti-fogging film exhibiting anti-fogging properties in which a water-absorbing layer containing a water-absorbing organic polymer is formed on the film substrate surface has been proposed (see Patent Document 4). Specifically, examples of the water-absorbing organic polymer include polyvinyl alcohol, polyacrylic acid, polyacrylic acid soda, polyalkylene oxide and the like. Particularly, polyvinyl alcohol has excellent film-forming properties, such as tensile strength, tear strength, friction. Since physical properties such as strength are superior to other water-absorbing resins, it is further preferred.

However, although the water-absorbing layer made of the water-absorbing organic polymer can obtain sufficient water-absorbing property, the swollen water-absorbing layer at the time of water absorption has a problem that it has poor mechanical strength and sometimes dissolves. Furthermore, polyvinyl alcohol forms a three-dimensional structure by a cross-linking reaction with a catalyst, but there is a technical problem that it is difficult to control the baking process and easily cause poor curing.

On the other hand, an antifogging film having a water-absorbing layer and a surface protective layer in order on a transparent support and excellent in antifogging effect and scratch resistance has been proposed (see Patent Document 5). Specifically, the water-absorbing layer is formed of ethylene oxide-modified di (meth) acrylate obtained by adding 5 or more molecules of ethylene oxide, and the surface protective layer is formed by hydrolysis of silicon alkoxide. And / or a polycondensate thereof, and a hydrophilic organic compound.

However, the surface protective layer for the purpose of imparting scratch resistance requires a complicated process, while reducing the rate of water absorption into the water-absorbing layer and causing the problem of cloudiness. In addition, a water-absorbing layer obtained by ultraviolet irradiation of ethylene oxide-modified di (meth) acrylate formed by adding 5 or more molecules of ethylene oxide forming the water-absorbing layer has a technical problem that sufficient water absorption cannot be obtained.

As described above, in the conventional coating composition, it is possible to exert a good balance of the antifogging performance, water resistance performance, adhesion performance, optical performance, mechanical strength and sustainability of the obtained coating. could not.

Japanese Patent Laid-Open No. 2-16185 JP 2001-40294 A Japanese Patent No. 2943768 JP 2001-145982 A JP 2006-095927 A

The object of the present invention has been made by paying attention to such problems existing in the prior art. The object is composed of an antifogging composition layer (A) and a transparent support layer (B) capable of exhibiting antifogging performance, water resistance performance, adhesion performance, optical performance, mechanical strength and their sustainability. The object is to provide a laminated anti-fogging film.

The present inventor has intensively studied to solve the above problems. As a result, a copolymer having an isocyanate group obtained from copolymerization of isocyanatoethyl (meth) acrylate, specific N-substituted alkyl (meth) acrylamide and (meth) acrylate monomer, and a hydroxyl value of 150 to 650 mgKOH / g A laminated anti-fogging film composed of an anti-fogging composition layer having a water absorption property of 1 to 100 g / m ² per area obtained by reacting the polyol with a transparent support layer (B) has a high anti-water absorption property due to its excellent water absorption. It was found that the fogging performance was developed. The present inventors have found that the laminated anti-fogging film has excellent water resistance, adhesion performance, optical performance, mechanical strength and sustainability that can withstand practical use, and have reached the present invention.

That is, the present invention provides a laminated antifogging film as shown below.
Item 1. In the laminated antifogging film composed of the antifogging composition layer (A) and the transparent support layer (B), the antifogging composition layer (A) is:
(A1) isocyanatoethyl (meth) acrylate monomer, (a2) general formula [I]

(Wherein R1 represents a hydrogen atom or a methyl group, R2 represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and R3 represents a linear or branched group having 1 to 4 carbon atoms. A copolymer (p1) having an isocyanate group obtained by copolymerization of an N-substituted alkyl (meth) acrylamide monomer (a3) and a (meth) acrylate monomer represented by: And an anti-fogging composition layer (A) having a water absorption property of 1 to 100 g / m ² per area obtained by reacting a polyol (p2) having a hydroxyl value of 150 to 650 mg KOH / g. the film.
Item 2. Item 2. The N-substituted alkyl (meth) acrylamide monomer (a2) is a monomer selected from at least one of N, N-dimethylacrylamide and N, N-diethylacrylamide. Laminated anti-fog film.
Item 3. Item 3. The laminated antifogging film according to Item 1-2, wherein the polyol (p2) is a polyol selected from at least one of a polyester polyol, a polyether polyol, and a polycarbonate polyol.
Item 4. Item 4. The laminated antifogging film according to items 1 to 3, wherein the antifogging composition layer (A) contains a surfactant.
Item 5. Item 5. The laminated antifogging film according to Item 1, wherein the transparent support layer (B) is an electromagnetic wave shielding layer (b1).
Item 6. Furthermore, the transparent support layer (B) surface opposite to the antifogging composition layer (A) is covered with an adhesive composition layer (C) and further protected with a release sheet (D). The laminated antifogging film as described.

  Hereinafter, the present invention will be described in detail.

  First, in the present invention, the antifogging composition layer (A) comprising the antifogging composition layer (A) constituting the laminated antifogging film and the transparent support layer (B) has a single antifogging composition layer (A). Consists of a copolymer (p1) having an isocyanate group obtained by copolymerization of a monomer (a1), a monomer (a2) and a monomer (a3) and a polyol (p2) having a hydroxyl value of 150 to 650 mgKOH / g. Has been.

  The isocyanatoethyl (meth) acrylate monomer which is the monomer (a1) is involved in curing of the copolymer (p1) and the polyol (p2) having a hydroxyl value of 150 to 650 mgKOH / g by urethane reaction. . Specific examples of the monomer (a1) include isocyanatoethyl acrylate and isocyanatoethyl methacrylate. In particular, isocyanatoethyl methacrylate is preferable from the viewpoints of polymerization reactivity, curing reactivity due to isocyanate groups, and stability of the obtained copolymer (p1).

  Next, the N-substituted alkyl (meth) acrylamide monomer as the monomer (a2) imparts water absorption to the antifogging composition layer (A). In particular, the general formula [I]

(Wherein R1 represents a hydrogen atom or a methyl group, R2 represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and R3 represents a linear or branched group having 1 to 4 carbon atoms. N-substituted alkyl (meth) acrylamide monomer represented by the formula (1) gives excellent water absorption to the resulting copolymer (p1) having an isocyanate group, and is antifogging. Demonstrate performance, optical performance and mechanical strength. Specific examples include N-methylacrylamide, N, N′-dimethylacrylamide, N-ethylacrylamide, N, N′-diethylacrylamide, Nn-propylacrylamide, N-isopropylacrylamide, Nn-butylacrylamide, N-methylmethacrylamide, N, N'-dimethylmethacrylamide, N-ethylmethacrylamide, N, N'-diethylmethacrylamide, Nn-propylmethacrylamide, N-isopropylmethacrylamide, Nn-butylmethacryl Amides are mentioned. In particular, N, N′-dimethylacrylamide and N, N′-diethylacrylamide are suitable because they have a good balance between water absorption and mechanical strength, and a highly transparent copolymer (p1) can be obtained.

  Moreover, the (meth) acrylate monomer which is the monomer (a3) imparts excellent water resistance, adhesion, optical performance and mechanical strength to the antifogging composition layer (A). From the viewpoint of the storage stability of the copolymer (p1), the (meth) acrylate monomer (a3) preferably has no active hydrogen group that reacts with an isocyanate group, and the alkyl group has 1 to 18 carbon atoms. (Meth) acrylic acid alkyl ester, for example, (meth) acrylic acid methyl, ethyl, propyl, butyl, octyl, 2-ethylhexyl, decyl, dodecyl, stearyl ester and the like. Further, ether oxygen-containing alkyl esters having 3 to 18 carbon atoms of (meth) acrylic acid, for example, methoxyethyl ester, ethoxyethyl ester, methoxypropyl ester, methyl carbyl ester, ethyl carbyl ester, butyl carbyl ester, etc. It is done.

  Next, the copolymer (p1) having an isocyanate group composed of the monomer (a1), the monomer (a2) and the monomer (a3) is copolymerized with a mixture of the monomers. Although obtained by reacting, the polymerization method is not particularly limited, and various conventionally known polymerization methods can be used. For example, the copolymer (p) is obtained by reacting the monomer mixture in the presence of a radical polymerization initiator at a reaction temperature of 60 to 120 ° C., more preferably 75 to 100 ° C. for 3 to 12 hours. It is done. In particular, solution polymerization is advantageous from the viewpoint of productivity and workability.

As the polymerization initiator, for example, azo compounds such as 2,2'-azobisisobutyronitrile and 2,2'-azobis-2-methylbutyronitrile, and peroxides such as benzoyl peroxide are preferable. The amount of the polymerization initiator used is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the monomer mixture.

As an organic solvent used for solution polymerization, an organic solvent that does not have an active hydrogen group that reacts with an isocyanate group can be used alone or in admixture of two or more. Specific examples of such organic solvents include ester solvents such as ethyl acetate and butyl acetate, ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, aromatic solvents such as toluene and xylene, methylcyclohexane and ethylcyclohexane. And aliphatic solvents such as tetrahydrofuran and ether solvents such as tetrahydrofuran and dioxane. The boiling point of the solvent is preferably 60 ° C to 180 ° C from the viewpoint of stability during polymerization, drying properties during coating, and influence on the substrate to be coated.

  Next, the polyol (p2) constituting the antifogging composition layer (A) has a hydroxyl value of 150 to 650 mgKOH / g. When the hydroxyl value is less than 150 mgKOH / g, the crosslinking density is too low and the coating film strength does not reach a practical level, and when the hydroxyl value exceeds 650 mgKOH / g, the coating film may become hard and brittle. Absent.

Specific examples of such polyol (p2) include polyester polyol, polyether polyol, polycarbonate polyol, polycaprolactone polyol, polyacryl polyol, polyurethane polyol and the like. From the viewpoint of the mechanical strength of the antifogging composition layer (A) and the adhesion to the transparent support layer (B), polyester polyols, polyether polyols and polycarbonate polyols are preferred.

More specifically, examples of the polyester polyol include succinic acid polyol, adipic acid polyol, terephthalic acid polyol, isophthalic acid polyol, phthalic acid polyol, and the like, and commercially available products such as FSK-700 (Kawasaki Kasei). Co., Ltd .: hydroxyl value 150), Kuraray polyol F-510 (Kuraray Co., Ltd .: hydroxyl value 336), Desmophen 651 (manufactured by Sumika Bayer Urethane Co., Ltd .: hydroxyl value 182), FLEXOREZ188 (KING INDUSTRIES INC.). : Hydroxyl value 230), Worlee Pol 1181/09 (Worlee-Chemie GmbH: hydroxyl value 330), polylite OD-X-2733 (manufactured by DIC Corporation: hydroxyl value 540), NIPPOLAN 170 (Nippon Polyurethane Industry Co., Ltd.) Ltd.: mention may be made of a hydroxyl value of 240), and the like.

Examples of the polyether polyol include an ethylene group, a propylene group, and a trimethylene group. Examples of commercially available products include Exenol 420 (Asahi Glass Co., Ltd .: hydroxyl value 280), Exenol 430 (Asahi Glass Co., Ltd.). : Hydroxyl value 400), Exenol 385SO (Asahi Glass Co., Ltd. product: hydroxyl value 385), Adeka polyether GM-30 (manufactured by ADEKA Corp .: hydroxyl value 540), PTMG-250 (manufactured by DuPont Co., Ltd .: hydroxyl value) 449) and the like.

  The polycarbonate polyol is obtained by a conventional reaction of a known polyhydric alcohol with phosgene, chloroformate, dialkyl carbonate, diaryl carbonate, alkylene carbonate, etc., and at least at least 2 in average, preferably 3 Examples of the commercially available product include Duranol T5650E (manufactured by Asahi Kasei Chemicals Corporation: hydroxyl value 225).

Next, the method for producing the antifogging composition layer (A) in the present invention is applied by a generally known wet coating method, and the coating liquid (COT1) at that time has the above isocyanate group. The copolymer (p1) and the polyol (p2) are essential components. The coating liquid (COT1) may be mixed in advance, but from the viewpoint of coating workability and storage stability, the coating liquid (COT1a) containing a copolymer (p1) having an isocyanate group. It is desirable to prepare two liquids of a coating liquid (COT1b) containing a polyol and a polyol (p2) and to prepare them when coating.

The coating solution (COT1a) is a copolymer (p1) having an isocyanate group, and the coating solution (COT1b) is an organic solvent, a curing accelerator and a surfactant, respectively, in addition to the polyol (p2). Etc. may be contained. In particular, the addition of a surfactant is suitable in order to change the water condensed on the surface into a water film when water exceeding the water absorption amount of the antifogging composition layer (A) is present, thereby eliminating fogging.

Here, as the organic solvent used in the coating liquids (COT1a) and (COT1b), an organic solvent having no active hydrogen group that reacts with an isocyanate group can be used alone or in combination of two or more. . Specific examples of such organic solvents include ester solvents such as ethyl acetate and butyl acetate, ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, aromatic solvents such as toluene and xylene, methylcyclohexane and ethylcyclohexane. And aliphatic solvents such as tetrahydrofuran and ether solvents such as tetrahydrofuran and dioxane. From the viewpoint of the drying property during coating and the influence on the substrate, the boiling point of the solvent is preferably 60 ° C to 180 ° C.

Examples of the curing accelerator include monoamine triethylamine, N, N-dimethylcyclohexylamine, diamine tetramethylethylenediamine, other triamines, cyclic amines, alcohol amines such as dimethylethanolamine, ether amines, and metal catalysts. Potassium acetate, potassium 2-ethylhexanoate, calcium acetate, lead octylate, dibutyltin dilaurate, tin octylate, bismuth neodecanoate, bismuth oxycarbonate, bismuth 2-ethylhexanoate, zinc octylate, zinc neodecanoate Commonly used materials such as phosphine, phospholine and the like can be used. The blending ratio of the curing accelerator is not particularly limited, but is 0.001 to 3.0 weight with respect to 100 weight parts of the total amount of the copolymer (p1) having the isocyanate group and the polyol (p2). Part.

As the surfactant, it is possible to select and use from generally used nonionic surfactants, anionic surfactants, cationic surfactants, zwitterionic surfactants and the like. Specifically, nonionic surfactants include polyoxyethylene lauryl alcohol, polyoxyethylene lauryl ether, polyoxyethylene higher alcohol ethers such as polyoxyethylene oleyl ether, polyoxyethylene octylphenol, polyoxyethylene nonylphenol. Polyoxyethylene alkyl aryl ethers such as polyoxyethylene acylesters such as polyoxyethylene glycol monostearate, polyoxyethylene acylesters such as polypropylene glycol ethylene oxide adducts, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monostearate, etc. Phosphoric acid of ethylene sorbitan aliphatic esters, alkyl phosphate esters, polyoxyethylene alkyl ether phosphate esters Ester ethers, sugar esters, and cellulose ethers and the like.

Examples of anionic surfactants include fatty acid salts such as sodium oleate and potassium oleate, higher alcohol sulfates such as sodium lauryl sulfate and ammonium lauryl sulfate, alkylbenzene sulfones such as sodium dodecylbenzenesulfonate and sodium alkylnaphthalenesulfonate. Examples include acid salts and alkylnaphthalene sulfonates, naphthalene sulfonic acid formalin condensates, dialkyl sulfosuccinates, dialkyl phosphate salts, polyoxyethylene sulfate salts such as sodium polyoxyethylene alkylphenyl ether sulfate, and the like.

Cationic surfactants include ethanolamines, laurylamine acetate, triethanolamine monoformate, amine salts such as stearamide ethyl diethylamine acetate, lauryltrimethylammonium chloride, dilauryldimethylammonium chloride, distearyldimethylammonium And quaternary ammonium salts such as chloride and lauryldimethylbenzylammonium chloride.

Examples of the zwitterionic surfactant include fatty acid type amphoteric surfactants such as dimethylalkyl lauryl betaine and dimethylalkyl stearyl betaine, sulfonic acid type amphoteric surfactants such as dimethylalkyl sulfobetaine, and alkylglycine.

In addition to the above additions, generally known UV absorbers, light stabilizers, reaction retarders, surface conditioners, storage stabilizers, heat stabilizers, inorganic fillers, etc. may be added as necessary. good.

Next, as the transparent support layer (B) used in the present invention, a known transparent resin can be used. For example, polyolefin resins such as polyethylene and polypropylene; polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol , Vinyl resins such as ethylene / vinyl acetate copolymer and ethylene / vinyl alcohol copolymer; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; methyl poly (meth) acrylate, poly (meth) ethyl acrylate, etc. Acrylic resins such as styrene resins such as polystyrene, acrylonitrile / butadiene / styrene copolymers, cellulose triacetate, cellophane, polycarbonate, polyurethane resins and other elastomer resins can be used. Among these, polyesters excellent in strength, durability, dimensional stability, and transparency are preferable, and polyethylene terephthalate (hereinafter referred to as “PET”) is particularly preferable.

PET contains ethylene glycol and terephthalic acid as main components, but may be copolymerized with other dicarboxylic acid components and glycol components as long as the object of the present invention is not impaired. Examples of the dicarboxylic acid component include isophthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, cyclohexane-1,4-dicarboxylic acid, and the like. Examples of the glycol component include propylene glycol, butanediol, neopentyl glycol, diethylene glycol and the like.

In the present invention, a transparent film formed using a known transparent resin is used for the transparent support layer (B). As the molding method, any of an unstretched film, a uniaxially stretched film, and a biaxially stretched film can be used, but a biaxially stretched film is preferable from the viewpoint of transparency and strength. The thickness of the transparent support layer (B), that is, the thickness of the transparent film is usually 1 to 500 μm, particularly 3 to 250 μm, and further 5 to 200 μm. Here, the preferred thickness varies depending on the purpose and usage of the laminated antifogging film according to the present invention, but generally when it is too thin, the strength of the antifogging film tends to be insufficient, and when it is too thick. Flexibility tends to be impaired.

In addition, the transparent support layer (B), particularly PET film, usually contains various additives such as inorganic fine particles, waxes, antioxidants, antistatic agents, crystal nucleating agents, thinning agents, heat Stabilizers, anti-coloring agents, ultraviolet absorbers and the like may be contained. Furthermore, for the purpose of using the laminated antifogging film in the present invention, it is desirable to impart an electromagnetic wave shielding function to the transparent support layer (B).

Here, the electromagnetic waves shown in the present invention indicate radio waves, infrared rays, visible rays, ultraviolet rays, X-rays and gamma rays. In particular, when used in optical applications, it is necessary to block a specific wavelength of 10 nm to 1 mm. From the viewpoint of human health and environmental impact, UVA (400 to 315 nm), UVB ( 315 to 280 nm), UVC (less than 280 nm), from the viewpoint of blocking heat energy transmission, among infrared rays in the 700 nm to 1 mm region, mid-infrared (2.5-4 μm), far infrared (4-1000 μm), one region each It is desirable to block the above according to the purpose.

Next, plasma treatment may be performed in advance as long as the object of the present invention is not impaired for the purpose of imparting adhesion between the laminated films to the transparent film which is the transparent support layer (B).

Here, the plasma treatment is performed by activating the surface by applying a high-frequency voltage between opposing electrodes to discharge it, bringing the atmospheric gas into a plasma state, and exposing the workpiece to this plasma state gas. is there. As the atmospheric gas used, nitrogen, oxygen, argon, helium, or the like can be used. Among them, nitrogen is preferably used from the viewpoint of safety, exhaust gas aftertreatment, running cost, and the like.

In addition to this, it is also possible to use a surface treatment that irradiates energy rays such as ultraviolet rays, electron beams, and ion rays. In particular, UV sources include D ₂ lamp, high pressure mercury lamp, low pressure mercury lamp, Xe lamp, Hg-Xe lamp, halogen lamp, arc discharge, corona discharge, silent discharge discharge lamp, excimer laser, Ar + laser, Kr + A laser oscillation device such as a laser or an N ₂ laser is preferably used. The surface treatment with energy rays can be performed before, after or simultaneously with the plasma treatment.

Further, as long as the object of the present invention is not hindered, pretreatment such as primer application may be performed without being limited to the presence or absence of plasma treatment or the like.

The coating method of the coating liquid (COT1) for imparting the antifogging function in the present invention to the transparent support layer (B) can be applied by a known method, and then subjected to a drying step. A coating film can be formed.

Although it does not specifically limit as a coating method, The method of coating using a coater etc. are mentioned. Examples of the coater include a bar coater, a comma coater, a die coater, a roll coater, a reverse roll coater, a gravure coater, a gravure reverse coater, and a flow coater. When coating, the thickness of the coating film can be controlled arbitrarily by adjusting the coating amount. As thickness of the coating film after drying, 3-30 micrometers is preferable. The temperature in the drying step is preferably 70 to 150 ° C.

The antifogging composition layer (A) thus obtained needs to exhibit excellent water absorption. In particular, in order to exhibit a durable antifogging effect, the water absorption amount of the antifogging composition layer (A) must have a water absorption characteristic of 1 to 100 g / m ² per area. Here, sufficient anti-fogging performance cannot be obtained with a water absorption of less than 1 g / m ² . On the other hand, if the amount of water absorption exceeds 100 g / m ² , the mechanical strength of the antifogging composition layer (A) after water absorption will fall below a practical level.

  Moreover, in this invention, it covers with the adhesive composition layer (C) with respect to the transparent support layer (B) surface on the opposite side to the said anti-fogging composition layer (A) as needed, and also protects with a peeling sheet (D). The embodiment is suitable from the viewpoint of practicality.

Examples of the pressure-sensitive adhesive forming the pressure-sensitive adhesive composition layer (C) include acrylic ester copolymers, natural rubber, styrene-butadiene copolymer rubber (SBR), ethylene-vinyl acetate copolymer, dimethyl silicone, and methylphenyl silicone. An adhesive such as urethane is used. The thickness of the pressure-sensitive adhesive composition layer (C) is usually 5 to 100 μm, preferably 10 to 60 μm.

Further, the release sheet (D) may be made of a known resin, such as paper such as glassine paper, coated paper, and laminated paper, plastic films such as polyolefin resin, vinyl resin, polyester resin, and the like. And the like coated with a release agent such as silicone resin. Although there is no restriction | limiting in particular about the thickness of this peeling sheet (D), Usually, it is about 20-150 micrometers.

The laminated antifogging film of the present invention is composed of an antifogging composition layer (A) and a transparent support layer (B) capable of achieving both excellent water absorption and mechanical strength, which is not found in the prior art, and has long-term durability and anti-fogging properties. It shows excellent performance in the durability of fogging effect. Furthermore, the laminated antifogging film of the present invention can be produced by a simple wet coating method without going through complicated steps, and in particular, due to the high reactivity of the copolymer (p1) having an isocyanate group belonging to the present invention, Compared with technology, it is a quick curing reaction even in a mild environment, and it is industrially superior without problems such as blocking (sticking phenomenon at the time of film winding due to uncured). Therefore, by these effects of the present invention, an anti-fogging performance, water resistance performance, adhesion performance, optical performance, mechanical strength and unprecedented laminated anti-fogging film can be obtained by a simple method, and Energy saving and cost reduction can be achieved.

It is the relationship between the light transmittance and wavelength of the laminated antifogging film of the present invention.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the following production examples and examples, “part” means “part by weight”.

(Production example: Production of copolymer P-1)
300 parts of toluene was placed in a reaction vessel equipped with a stirrer, condenser, thermometer, dropping device, nitrogen inlet tube, and heating / cooling jacket, and the mixture was heated and stirred under a nitrogen stream at 85 ° C. While maintaining the same temperature, 170 parts of N, N'-diethylacrylamide, 5 parts of ethyl acrylate, 25 parts of isocyanatoethyl methacrylate and polymerization initiator 2,2'-azobisisobutyro are introduced into the reactor from the dropping device. A mixture of 4 parts of nitrile was added dropwise over 2 hours. Then, after stirring at the same temperature for 3 hours, 0.5 part of 2,2′-azobisisobutyronitrile was added and further stirred at the same temperature for 2 hours to obtain a colorless and transparent copolymer solution P-1. Obtained.

The heating residue (heating residue after drying for 3 hours in a 105 ° C. incubator) of the obtained copolymer solution P-1 was 41.9%, and the viscosity at 23 ° C. was 120 mPa · s. The NCO% measured by a conventional method was 1.4%, and the presence of hydroxyl groups was not observed.

“Copolymer P-2” to “copolymer P-1” to “copolymer P-1” were produced in the same manner as in the above production method, except that the dropwise addition components were changed as shown in Table 1 and Table 2. Copolymer P-5 ”and“ Copolymer C-1 ”to“ Copolymer C-4 ”for Comparative Examples were obtained. In the same manner as described above, the viscosity (B-type viscometer), NCO%, and hydroxyl value of these copolymers were measured. The results are shown in Table 1 and Table 2.

In addition, the symbol in Table 1 and Table 2 represents the following meaning.
N-DMAAm: N, N'-dimethylacrylamide, trade name manufactured by Kojin Co., Ltd.
N-DEAAm: N, N'-diethylacrylamide, trade name DEAA manufactured by Kojin Co., Ltd.
N-iPAAm: N-isopropylacrylamide, trade name NIPAM manufactured by Kojin Co., Ltd.
MMA: Methyl methacrylate, reagent grade product manufactured by Wako Pure Chemical Industries, Ltd. EA: Ethyl acrylate, reagent grade product manufactured by Wako Pure Chemical Industries, Ltd. MEA: 2-methoxyethyl acrylate, reagent grade, manufactured by Wako Pure Chemical Industries, Ltd. Product MOI: Isocyanatoethyl methacrylate, trade name Karenz MOI manufactured by Showa Denko K.K.
HEAA: 2-hydroxyethylacrylamide, trade name HEAA manufactured by Kojin Co., Ltd.
AIBN: 2,2′-azobisisobutyronitrile, a reagent special grade manufactured by Wako Pure Chemical Industries, Ltd.

(Example: Production of laminated anti-fogging film [Example 1])
Synthesized copolymer solution P-1 (NCO% 2.2): 100 parts, Polylite OD-X-2733 which is a polyol (manufactured by DIC Corporation: hydroxyl value 540): 3.5 parts, toluene: 46. 4 parts and dibutyltin dilaurate (product name Neostan U-100 manufactured by Nitto Kasei Co., Ltd.): 0.1 part as a curing accelerator were mixed and stirred until the whole liquid became uniform. The obtained coating solution was treated with a bar coater No. No. 10 was applied to a PET film (Cosmo Shine A4300 [double-sided easy adhesion treatment: thickness 100 μm]) to a dry film thickness of 10 ± 2 μm, followed by hot air drying at 80 ° C. for 5 minutes and room temperature. The sample cooled to the above was used for the test.

Although it implemented similarly to the said method also about Examples 2-10 and Comparative Examples 1-10, the compounding composition or drying conditions of a coating liquid differ. The respective composition and drying conditions are shown in Tables 3 to 6.

In addition, the symbol in Table 3-Table 6 represents the following meaning.
(Polyol)
PO-1: Desmophen 651, manufactured by Sumika Bayer Urethane Co., Ltd .: hydroxyl value 182
PO-2: Polylite OD-X-2733, manufactured by DIC Corporation: hydroxyl value 540
PO-3: ADEKA polyether GM-30, manufactured by ADEKA Corporation: hydroxyl value 540
PO-4: Duranol T5650E, manufactured by Asahi Kasei Chemicals Corporation: hydroxyl value 225
(Surfactant)
SF-1: Polyoxyethylene [n = 2] lauryl ether (HLB: 6.8), trade name, Emulgen 102KG, manufactured by Kao Corporation
SF-2: Polyoxyethylene [n = 3] lauryl ether (HLB: 8.1), trade name, Emulgen 103, manufactured by Kao Corporation
SF-3: Polyoxyethylene [n = 8] oleyl ether (HLB: 10.0), trade name Emulgen 408 manufactured by Kao Corporation
SF-4: Sodium di (2-ethylhexyl) sulfosuccinate, reagent product manufactured by Tokyo Chemical Industry Co., Ltd. SF-5: Polyether-modified silicone, product name FZ-2105 manufactured by Toray Dow Corning Co., Ltd.
(Isocyanate)
TPA-100: Duranate TPA-100 (NCO% = 23.5), manufactured by Asahi Kasei Chemicals Corporation (curing accelerator)
DBTDL: Dibutyltin dilaurate, trade name Neostan U-100 manufactured by Nitto Kasei Co., Ltd.
(Curing conditions)
Condition-1: 80 ° C. × 5 minutes Condition-2: 120 ° C. × 2 minutes

Next, the antifogging performance and physical properties of each laminated antifogging film thus obtained were evaluated according to the evaluation methods shown below. The results are shown in Tables 3 to 6.

<Dryness of coating film>
A gauze was laid on the anti-fogging composition layer of the obtained laminated anti-fogging film, a weight of 500 g was placed thereon, and the appearance of the coating film was evaluated visually after 1 hour in a 40 ° C. atmosphere.
A: No gauze marks are observed.
○: Small irregularities are observed.
Δ: Large irregularities are observed.
X: Gauze is stuck.

<Adhesion>
It evaluated from the peeling state of the anti-fogging composition layer according to JISK5600-5-6.
◯: No separation is observed Δ: Small separation is observed at the intersection of the crosscut portion.
X: Large peeling is recognized

<Water resistance>
The obtained laminated antifogging film was immersed in warm water at 40 ° C. for 240 hours, and then the appearance of the coating film dried at room temperature was visually evaluated.
○: No change at all Δ: Thin whitening occurs x: Defects in the coating film such as whitening and peeling occur

<Scratch resistance>
Steel wool (# 0000) was laid on the anti-fogging composition layer of the obtained laminated anti-fogging film, and a weight of 500 g was placed thereon and moved 10 times in a width of 10 cm. Next, the tested laminated antifogging film was washed with water, dried, and then visually evaluated for the presence or absence of scratches.
A: No scratch marks are observed.
○: Small scratch marks are partially observed.
Δ: Small scratch marks are observed throughout.
X: Large scratch marks are observed throughout.

<Exhalation anti-fogging property>
Exhaled air was sprayed on the antifogging composition layer of the obtained laminated antifogging film at room temperature, and the presence or absence of fogging generated on the surface was visually evaluated.
◎: No cloudiness is observed. ○: Cloudiness is generated when the exhalation is blown for 5 seconds or more. Δ: Clouding is observed, but the clouding is eliminated after the expiration is finished. X: Clouding is recognized

<Low-temperature breath anti-fogging property>
The obtained laminated anti-fogging film was stored at 5 ° C. for 1 hour, and then the breath was immediately blown on the anti-fogging composition layer to visually evaluate the presence or absence of fogging on the surface.
◎: No cloudiness is observed. ○: Cloudiness is generated when the exhalation is blown for 5 seconds or more. Δ: Clouding is observed, but the clouding is eliminated after the expiration is finished. X: Clouding is recognized

<Steam anti-fogging property>
40 ° C. steam was continuously sprayed on the anti-fogging composition layer of the laminated anti-fogging film, and the presence or absence of fogging formed on the surface after 1 hour was visually evaluated. A film is formed. ○: No cloudiness is observed and large water droplets are formed. Δ: Cloudiness is observed, but the cloudiness disappears after completion of steam irradiation at 40 ° C. ×: Cloudiness is recognized

<Anti-fogging durability>
The obtained laminated antifogging film is immersed in warm water at 40 ° C. for 1 hour, dried at room temperature, and exhaled at the room temperature on the antifogging composition layer. evaluated.
◎: No cloudiness is observed. ○: Cloudiness is generated when the exhalation is blown for 5 seconds or more. Δ: Clouding is observed, but the clouding is eliminated after the expiration is finished. X: Clouding is recognized

<Water absorption measurement>
The obtained laminated antifogging film was cut out at 10 × 10 cm, dried under reduced pressure (vacuum) for 2 hours in a 50 ° C. atmosphere, and then quickly measured for dry weight. Next, after the laminated anti-fogging film was immersed for 1 hour using 2 L of distilled water at a temperature of 10 ° C., the laminated anti-fogging film was taken out, the water adhering to the back surface and the like was wiped off, and the weight was measured. The laminated antifogging film after the test was again dried at 50 ° C. under reduced pressure (vacuum) for 2 hours, and the dry weight was quickly measured. From the results of carrying out the above method five times, the water absorption amount was calculated from the average value of three points excluding the upper limit value and the lower limit value.

(Evaluation of optical properties of film)
Using the laminated antifogging film obtained in Example 3 above, an acrylic pressure-sensitive adhesive (GD-4015NFUV) was applied to the opposite side of the antifogging composition layer and covered with a PET film release sheet having a thickness of 25 μm. . This laminated antifogging film exhibited the following physical properties. Here, the visible light transmittance, the ultraviolet transmittance, the solar transmittance, the solar absorption rate, and the shielding coefficient were calculated according to JIS A5759 using an integrating sphere light transmittance measuring device. The heat transmissivity was calculated according to JIS A5759 using an emissometer. The results are shown in Table 7.

Moreover, the relationship between the light transmittance and wavelength of the laminated antifogging film obtained in Example 3 is shown in FIG.

The laminated antifogging film of the present invention is composed of an antifogging composition layer (A) and a transparent support layer (B) capable of achieving both excellent water absorption and mechanical strength, which is not found in the prior art, and has long-term durability and anti-fogging properties. It shows excellent performance in the durability of fogging effect. Furthermore, the laminated antifogging film of the present invention is industrially excellent without going through complicated steps. Therefore, due to the effects of the present invention, in addition to anti-fogging measures in the window glass, lenses, mirrors and optical sensors that are the technical field of the present invention, it can be applied to agricultural greenhouse materials, packaging films, etc. Furthermore, it is considered that the water absorption of the present invention can be used in the field of films having heat dissipation characteristics by utilizing the heat of vaporization of the absorbed water.

Claims (6)

In the laminated antifogging film composed of the antifogging composition layer (A) and the transparent support layer (B), the antifogging composition layer (A) is:
(A1) isocyanatoethyl (meth) acrylate monomer, (a2) general formula [I]

(Wherein R1 represents a hydrogen atom or a methyl group, R2 represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and R3 represents a linear or branched group having 1 to 4 carbon atoms. A copolymer (p1) having an isocyanate group obtained by copolymerization of an N-substituted alkyl (meth) acrylamide monomer (a3) and a (meth) acrylate monomer represented by: And an anti-fogging composition layer (A) having a water absorption property of 1 to 100 g / m ² per area obtained by reacting a polyol (p2) having a hydroxyl value of 150 to 650 mg KOH / g. the film. The N-substituted alkyl (meth) acrylamide monomer (a2) is a monomer selected from at least one of N, N-dimethylacrylamide and N, N-diethylacrylamide. The laminated antifogging film as described. The laminated antifogging film according to claim 1 or 2, wherein the polyol (p2) is a polyol selected from at least one of a polyester polyol, a polyether polyol and a polycarbonate polyol. The laminated antifogging film according to claim 1, wherein the antifogging composition layer (A) contains a surfactant. The laminated antifogging film according to any one of claims 1 to 4, wherein the transparent support layer (B) is an electromagnetic wave shielding layer (b1). Furthermore, the transparent support layer (B) surface opposite to the antifogging composition layer (A) is covered with an adhesive composition layer (C) and further protected with a release sheet (D). The laminated antifogging film according to any one of 5.

Images