CN101301805A - Method for producing laminated film - Google Patents

Abstract

The present invention provides a method for manufacturing a laminated film in which a film is bonded using a photocurable epoxy resin adhesive without irradiation of light of very strong illuminance or heating after irradiation of light, the method comprising: the photocurable epoxy resin adhesive existing between the films is heated to a temperature of 40 ℃ or higher, and is irradiated with light to be cured, thereby bonding the films.

Description

Manufacturing method of laminated film

technical field

The present invention relates to a method for producing a laminated film that can be used in a wide range of fields. Specifically, it relates to a method for producing a laminated film in which films are bonded together using a photocurable epoxy resin adhesive.

Background technique

Laminated films are used in a wide range of fields including automobiles, airplanes, and electric and electronic devices. Especially in recent years, multilayer films in electrical and electronic devices have become increasingly diverse and sophisticated. In addition to the diversification and sophistication of laminated films, the production method of laminated films requires improvement in productivity, improvement in yield, simplification and automation of equipment, etc. while maintaining the quality of the produced laminated film.

For example, a polarizing plate used in an optical member or a liquid crystal display device is generally produced by bonding a protective film or an optical compensation film to both surfaces of a polyvinyl alcohol (PVA)-based polarizer film with an adhesive. As the adhesive, water-based adhesives or organic solvent-based adhesives are used, but in recent years, non-aqueous and non-organic solvent-based non-solvent adhesives, especially photocurable epoxy adhesives, have been used instead. Resin-based adhesive.

In the past, in the manufacture of a laminated film using a photocurable epoxy resin adhesive as an adhesive, in order to fully cure the photocurable epoxy resin adhesive, it was necessary to irradiate the light with a strong Either the heat of reaction accelerates the curing reaction, or the curing reaction is completed by heating in an oven or the like after irradiation with light (after cure). When the photocurable epoxy resin adhesive is irradiated with light, the photopolymerization initiator (catalyst) contained therein is activated to generate an acid. The acid reacts with the epoxy group of the photocurable epoxy resin, and the epoxy group opens a ring to generate a carbocation. This cation continuously reacts with the epoxy group of the epoxy resin, and the epoxy resin-based adhesive is cured. However, the reaction between carboions and epoxy groups is difficult to occur at room temperature, so it is necessary to irradiate light with strong illuminance or use an oven to heat after irradiating light, thereby accelerating or ending the reaction between carboions and epoxy groups .

If the light of strong illuminance is irradiated, the light will change due to heat. For example, in the case of a polarizer film, iodine discharge (ヨウエ抜け) will occur from a polyvinyl alcohol film (deflector (deflector) film) dyed with iodine or the like. , or the polarizer film or protective film or optical compensation film is deformed, thus degrading the quality.

In addition, when heating with an oven or the like after light irradiation, a heating device such as a heating oven is required. Especially when the line speed is fast, the heating oven becomes very long, and the operating cost and equipment investment cost increase.

Contents of the invention

The object of the present invention is to provide a light-curable epoxy resin-based adhesive that does not need to be irradiated with strong ultraviolet rays or heated (post-cured) after irradiating light in order to fully cure the photocurable epoxy resin-based adhesive. A method of manufacturing a laminated film in which films are bonded together with an adhesive.

The inventors of the present invention conducted intensive studies to solve the above-mentioned problems, and found that the above-mentioned problems can be achieved by heating the photocurable epoxy resin-based adhesive to a specific temperature before irradiating light. this invention.

According to the present invention, the following inventions 1 to 4 are provided.

(1) A method for producing a laminated film, which is a method for producing a laminated film in which films are bonded together using a photocurable epoxy resin adhesive, comprising: The curable epoxy resin adhesive is heated to a temperature of 40° C. or higher, and the adhesive is irradiated with light to be cured to bond the films.

(2) A film bonding method, which is a film bonding method that uses a photocurable epoxy resin adhesive to bond a polarizer film, a protective film and/or an optical compensation film, and is characterized in that , comprising: heating the photocurable epoxy resin adhesive present between the films to a temperature above 40°C and below the heat-resistant temperature of the film, and irradiating the adhesive with light to cure it Thereby bonding the film.

(3) The method according to (1) or (2), wherein the heating temperature is 40 to 120°C.

(4) The method according to any one of (1) to (3), wherein the light is ultraviolet rays in which at least a part of light having a wavelength of 400 nm or less is cut off.

With the bonding device of the present invention, it is not necessary to irradiate strong light or heat (post-cure) after irradiating light in order to fully cure the photocurable epoxy resin adhesive, so it is possible to easily and effectively manufacture high-quality adhesives. laminated films such as polarizers.

Detailed ways

The present invention will be described in detail below.

The photocurable epoxy resin-based adhesive used in the present invention contains a photocurable epoxy resin and a photopolymerization initiator, and may contain conventional additive components.

The photocurable epoxy resin is not particularly limited as long as it is a commonly used photocurable epoxy resin, and includes, for example, aromatic epoxy resins, aliphatic epoxy resins, and alicyclic epoxy resins.

Examples of the aromatic epoxy resin include bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol A epoxy resins, naphthalene skeleton epoxy resins, phenol novolac epoxy resins, and the like.

As the aliphatic epoxy resin, polyglycidyl ethers of aliphatic polyhydric alcohols or epoxide adducts thereof can be used. Examples of aliphatic epoxy resins include ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,4-Butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, trimethylolpropane diglycidyl ether, polyethylene glycol diglycidyl ether Glyceryl ether etc. In addition, unsaturated fatty acid epoxy resins such as butadiene-based epoxy resins and isoprene-based epoxy resins can also be used. Trimethylolpropane triglycidyl ether and trimethylolpropane diglycidyl ether are preferable because of their low viscosity. Commercially available aliphatic epoxy resins include, for example, Eporite 100MF (trimethylolpropane triglycidyl ether) manufactured by Kyoeisha Chemical Co., Ltd., EX-321L (trimethylolpropane triglycidyl ether) manufactured by Nagase Chemtex Co., Ltd. diglycidyl ether).

The alicyclic epoxy resin is a compound having one or more epoxy groups bonded to an alicyclic ring in the molecule, examples of which include vinylcyclohexene monoxide, 1,2-epoxy -4-vinylcyclohexane, 1,2:8,9 diepoxylimonene, 3,4-epoxycyclohexenylmethyl-3',4'-epoxycyclohexene carboxylic acid Esters etc. These are commercially available as CEL2000, CEL3000, and CEL2021P from Daicel Chemical Industry Co., Ltd.

As the photocurable epoxy resin in the present invention, the above-mentioned epoxy resins may be used alone, or a plurality of epoxy resins may be mixed and used in an arbitrary mixing ratio.

The photopolymerization initiator in the present invention is not particularly limited as long as it generates cations or Lewis acids by irradiation with active energy rays such as visible rays, ultraviolet rays, X-rays, and electron rays, and initiates the polymerization of epoxy groups. . Examples of photopolymerization initiators include sulfonium salts, iodonium salts, and diazonium salts.

As an example of a sulfonium system, such as

Triphenylsulfonium hexafluorophosphate

Triphenylsulfonium hexafluoroantimonate

Triphenylsulfonium tetrakis(pentafluorophenyl)borate

4,4'-Bis[diphenylsulfonium (sulfonio)]diphenylsulfide bishexafluorophosphate

4,4'-Bis[bis(β-hydroxyethoxy)phenylsulfonium]diphenylsulfide bishexafluoroantimonate

4,4'-Bis[bis(β-hydroxyethoxy)phenylsulfonium]diphenylsulfide bishexafluorophosphate

7-[Bis(p-toluoyl)sulfonyl]-2-isopropylthioxanthone hexafluoroantimonate

7-[Bis(p-toluoyl)sulfonyl]-2-isopropylthioxanthone tetrakis(pentafluorophenyl)borate

4-Phenylcarbonyl-4'-diphenylsulfonium-diphenylsulfide hexafluorophosphate

4-(p-tert-Butylphenylcarbonyl)-4'-diphenylsulfonium-diphenylsulfide hexafluoroantimonate

4-(p-tert-Butylphenylcarbonyl)-4'-bis(p-toluoyl)sulfonyl-diphenylsulfide tetrakis(pentafluorophenyl)borate

wait.

Examples of iodonium salts include

Diphenyliodonium tetrakis(pentafluorophenyl)borate

Diphenyliodonium hexafluorophosphate

Diphenyliodonium hexafluoroantimonate

Bis(4-nonylphenyl)iodonium hexafluorophosphate

wait.

Examples of diazonium salts include

Benzenediazonium hexafluoroantimonate

Benzenediazonium hexafluorophosphate

wait.

Commercially available photopolymerization initiators include Adeka Optima-SP-150 and SP-170 manufactured by Asahi Denka Co., Ltd., PI2074 manufactured by Rodia Co., Ltd., and Cayalad PCI-220 manufactured by Nippon Kayaku Co., Ltd. wait.

These photoinitiators are used in an amount of 0.5 to 20 parts by mass, preferably 1 to 10 parts by mass with respect to 100 parts by mass of the photocurable epoxy resin. A photoinitiator may be used individually, respectively, and may use 2 or more types.

The photocurable epoxy resin adhesive agent in this invention may contain an oxetane compound as needed. The oxetane compound is a compound having an oxetane ring which is a 4-membered cyclic ether in a molecule. Examples of oxetane compounds include 3-ethyl-3-hydroxymethyl oxetane, 1,4-bis[{(3-ethyl-3-oxetane )methoxy}methyl]benzene, 3-ethyl-3-(phenoxymethyl)oxetane, bis(3-ethyl-3-oxetanylmethyl)ether, 3-Ethyl-3-(2-ethylhexyloxymethyl)oxetane, 3-ethyl-[{(3-triethoxysilylpropoxy)methyl}oxetane Cyclobutane], oxetanyl silsesquioxane, phenol novolac oxetane, etc. Among these oxetane compounds, 3-ethyl-3-hydroxymethyl oxetane, bis(3-ethyl-3-oxetanylmethyl) ether, 3-ethane Base-3-(2-ethylhexyloxymethyl)oxetane. Commercially available oxetane compounds include, for example, OXT-101 (3-ethyl-3-hydroxymethyl oxetane), OXT-211 (3-ethyl oxetane), commercially available from Toagosei Co., Ltd. base-3-(phenoxymethyl)oxetane), OXT-221 (di[1-ethyl(3-oxetanyl)]methyl ether), OXT-212(3- ethyl-3-(2-ethylhexyloxymethyl)oxetane).

In this invention, an oxetane compound is used in the quantity of 50 mass parts or less with respect to 100 mass parts of photocurable epoxy resins. The oxetane compounds may be used alone or in combination of two or more.

The photocurable epoxy resin-based adhesive in the present invention may further use a photosensitizer in combination as needed. By using a photosensitizer, the reactivity is improved, and the mechanical strength or adhesive strength of the cured product can be improved. Examples of the photosensitizer include carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, and photoreducible dyes. Examples of photosensitizers include benzoin derivatives such as benzoin methyl ether, benzoin isopropyl ether, and α,α-dimethoxy-α-phenylacetophenone; , 2,4-dichlorobenzophenone, methyl benzoylbenzoate, 4,4'-bis(diethylamino)benzophenone and other benzophenone derivatives; 2-chlorothioxanthone, 2 - Thioxanthone derivatives such as isopropylthioxanthone and 2,4-diethylthioxanthone; anthraquinone derivatives such as 2-chloroanthraquinone and 2-methylanthraquinone; Acridone derivatives such as acridone and N-butylacridone; anthracene derivatives such as 9,10-dibutoxyanthracene; in addition, α,α-diethoxyacetophenone, Benzil, fluorenone, xanthone, lauryl compound, halogen compound, photoreducible dye, etc., but not limited to these. In addition, these photosensitizers may be used alone or in combination of two or more. As a commercial item of a photosensitizer, Kayakyua DETX-S (manufactured by Nippon Kayaku Co., Ltd.) etc. are mentioned, for example. The quantity of a photosensitizer is 0.01-20 mass parts with respect to 100 mass parts of photocurable epoxy resin adhesives, Preferably it is 0.1-5 mass parts.

As long as the effects of the present invention are not impaired, additives other than those described above, such as fillers, antioxidants, and silane coupling agents, may be added to the photocurable epoxy resin adhesive in the present invention.

Examples of fillers include inorganic fillers such as talc, silica, and mica, and resin fillers such as polypropylene and polyethylene.

Examples of antioxidants include dibutylhydroxytoluene (BHT), Iluganox 1010, Iluganox 1035FF, Iluganox 565, and the like.

Examples of silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-ethoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxy Propyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3- Methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-trimethoxysilane Ethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine and the like.

Commercially available silane coupling agents include, for example, epoxy-based (eg KBM403, KBM303), vinyl-based (KBM1003), acrylic-based silane coupling agents (KBM503), 3-ethyl (triethoxysilylpropane) Oxymethyl)oxetane (TESOX (manufactured by Toagosei Co., Ltd.)) and the like.

The photocurable epoxy resin adhesive in the present invention preferably has a viscosity of 200 mPa·s (25°C) or less, more preferably 150 mPa·s (25°C) or less. The lower the viscosity, the easier it is to apply. In addition, the application thickness of the adhesive layer can be reduced. For example, when it is used to attach a protective film or an optical compensation film to a polarizer, the appearance of the polarizer also becomes better. . High-viscosity adhesives can also be used, but in this case the application amount is reduced.

The films used in the present invention must be films in which at least one film transmits light. Examples of such light-transmitting films include polyester films, polycarbonate films, acrylic films, polyamide films, polyimide films, amorphous polyolefin films, cycloolefin films, and film. PVA-based film, cellulose-based film, etc.

Amorphous polyolefin-based resins are generally norbornene or resins having polymerized units of cyclic polyolefins such as polycyclic norbornene-based monomers, and may be copolymers of cyclic olefins and chain-shaped cyclic olefins . Commercially available non-crystalline polyolefin-based resins include AITON under the trade name of JSR Co., Ltd., ZEONEX and ZEONOR from Nippon Zeon Co., Ltd., APO and Apel from Mitsui Chemicals Co., Ltd., and the like.

In the present invention, it can be combined with a light-impermeable film, and the light-impermeable film can also be used, for example, as a base film of a laminated film. Examples of such light-impermeable films include resins that contain coloring pigments, coloring dyes, carbon black, inorganic particles, or polymer particles for coloring or light-shielding, and do not transmit light in the wavelength region of 450 nm or less. Transient polyimide film, etc.

The thickness of each film in the present invention is not particularly limited, and films of various thicknesses can be used as needed.

When the laminated film is a polarizing plate, a PVA-based polarizer film, a cellulose-based film such as triacetyl cellulose, a protective film such as a cycloolefin-based film, or an optical compensation film can be used.

In the present invention, the method for applying the photocurable epoxy resin adhesive to the substrate film is not particularly limited, and examples include using a doctor blade, a bar, a metal die coater, and a Kangma coater (Kanma Coater).タ one), gravure coating machine and other methods. In addition, the lamination of the film in the present invention can be performed using metal rolls, rubber rolls, etc., and the lamination pressure at this time can be 0 to 5 MPa.

The laminated film in the present invention may have a laminated structure composed of 2-layer, 3-layer, 4-layer, 5-layer, 6-layer or more films.

In the present invention, a film subjected to corona treatment, plasma treatment, excimer treatment, UV treatment, etc. on the adhesive surface of the film can also be used.

The heating temperature of the photocurable epoxy resin-based adhesive in the present invention must be 40° C. or higher. The upper limit of the heating temperature is the heat-resistant temperature of the adherend film, which depends on the heat resistance of the adherend film, so it cannot be limited, for example, it is 120°C. Here, the heat-resistant temperature of the film means that when the film is placed at a certain temperature for 60 seconds, compared with before heating, there is actually no deformation (warpage, deformation) of the film and the optical properties (transmittance) of the film , degree of polarization) the highest temperature among the temperatures at which no deterioration occurs. When the heating temperature of the adhesive is 40° C. or lower, the curing of the photocurable epoxy resin by light irradiation is insufficient, and the effect of the present invention cannot be obtained. The heating temperature of the adhesive is preferably 50 to 100°C, more preferably 60 to 80°C.

The heating of the photocurable epoxy resin adhesive in the present invention includes, for example, a near-infrared halogen lamp, a far-infrared heater, hot air, a heating plate, and a heating roller, but is not limited thereto.

The light in the present invention refers to active energy rays such as visible rays, ultraviolet rays, X-rays, and electron rays, and is preferably ultraviolet rays. Light irradiation can be performed using a metal halide lamp, a high-pressure mercury lamp, a xenon lamp, a halogen lamp, or the like. In the case of using ultraviolet rays, in order to minimize the deterioration of the film, it is preferable not to contain at least a part of light having a wavelength of 400 nm or less, preferably 390 nm or less, and more preferably not to contain all ultraviolet rays having a wavelength of 400 nm or less, preferably 390 nm or less. Such ultraviolet rays can be obtained, for example, by using a near-infrared cut filter or an optical filter that cuts off light having a wavelength of 310 or 390 nm or less between the ultraviolet lamp and the adherend film. Examples of such optical filters include quartz glass, thermal cut filter (IRCF), cut filter below 310nm, cut filter at 320nm, cut filter at 340nm, cut filter at 390nm, soda lime glass, 400-450nm band pass filter etc.

Irradiation of light in the present invention is performed when the temperature of the photocurable epoxy resin-based adhesive is 40° C. or higher. The irradiation intensity of light in the present invention varies depending on the intended adhesive or resin film, and is not limited. The irradiation intensity in the wavelength region effective for activating the photopolymerization initiator is preferably 10 to 500 mW/cm ² . The irradiation time of light varies depending on the type of photocurable epoxy resin used or the material of the film, and is not limited, but the accumulated light amount expressed as the product of irradiation intensity and irradiation time is 100 to 3000mJ/cm ² (wavelength 405nm), Preferably, it is 700 to 2000 mJ/cm ² (wavelength 405 nm).

[Example]

The present invention is shown below using examples, but the present invention is not limited by these examples.

Production Examples A-F Preparation of Photocurable Epoxy Resin Adhesives

The following raw materials were measured and added to a container made of polyethylene, and mixed and stirred with a mixer to obtain a uniform photocurable epoxy resin adhesive (viscosity: 150 mPa/s (25° C.)).

[Table 1]

100MF: Trimethylolpropane triglycidyl ether, Kyoyoung Chemical Co., Ltd.

Epichrome EXA-850S: 4,4'-diglycidyloxy-2,2'-diphenylpropane, Dainippon Ink Chemical Co., Ltd.

Epichrome N740: Phenol Novolak Type Epoxy Oligomer, Dainippon Ink Chemicals Co., Ltd.

CEL2000: 1,2-epoxy-4-vinylcyclohexane, Daicel Chemical Industry Co., Ltd.

CEL3000: 1, 2: 8, 9 Diepoxylimonene, Daicel Chemical Co., Ltd.

CEL2021P: 3,4-epoxycyclohexenylmethyl-3',4'-epoxycyclohexene carboxylate, Daicel Chemical Co., Ltd.

CPI-101A: Photopolymerization Catalyst Sunapro Co., Ltd.

SP-172: Photopolymerization catalyst, ADEKA Co., Ltd.

KBM403: 3-Glycidoxypropyltrimethoxysilane, Shin-Etsu Chemical Co., Ltd.

DBA: 9,10-Dibutoxyanthracene, Kawasaki Chemical Industry Co., Ltd.

Production of Laminated Films (Polarizers) of Examples 1-6 and Comparative Examples 1-3

By means of the photocurable epoxy resin adhesive (symbol: A) prepared in the production example, a triacetyl cellulose film was bonded to one side of a polyvinyl alcohol polarizer film that was uniaxially stretched and dyed with iodine, An amorphous polyolefin-based resin film (Zionoa Film manufactured by Nippon Zeon Co., Ltd.) was bonded to the other surface to obtain a film having a three-layer structure. Using an infrared lamp, heat the obtained three-layer structure film to room temperature (25°C), 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 100°C, 120°C, and 140°C, and use it immediately A metal halide lamp (manufactured by Aigraficus Co., Ltd.) was irradiated with light at an irradiation intensity of 200 mW/cm ² (405 nm) and a cumulative light intensity of 1000 mJ/cm ² (405 nm), to obtain a laminated film. The adhesive layer between the laminated films has a uniform thickness of about 1 to 3 μm. These results were confirmed using electron microscopy.

Table 2 shows the material temperature, the state of the adhesive after UV irradiation, the deformation of the laminated film after UV irradiation, the durability characteristics of the laminated film, and the optical characteristics after the humidity resistance test.

[Table 2]

Examples or comparative examples Material temperature (℃) The state of the adhesive after UV irradiation Deformation of film after UV irradiation Durability characteristics after humidity resistance test Optical properties after humidity test Comparative example 1 25 In liquid state, insufficient solidification none × - Comparative example 2 30 In liquid state, insufficient solidification none × - Example 1 40 △ none × - Example 2 50 ○ none × - Example 3 60 ◎ none △ somewhat worse Example 4 70 ◎ none △ no change Example 5 80 ○ slightly warped △ no change Example 6 100 ○ greatly warped × - Comparative example 3 140 exfoliation greatly deformed × -

Material temperature: The temperature of the adhesive before UV irradiation (heating temperature)

The state of the adhesive after UV irradiation:

Evaluation was performed according to the following criteria.

In liquid state, insufficient curing: In liquid state, insufficient curing, no bonding

Peeling: The film is peeled off

△: Bonding, but the strength is somewhat weak (~100g/25mm)

○: Bonding, moderate strength (100～200g/25mm)

◎: Adhesive, sufficient strength (200g/25mm～)

Deformation of film after UV irradiation: observed with naked eyes.

Durability characteristics after humidity test:

The appearance (dye discharge or film denaturation) after the laminated film was left in a humidity resistance test tank under the condition of 60° C. to 90% for 500 hours was evaluated according to the following criteria.

×: Severe peeling, deformation, and dye discharge of the polarizer portion.

Δ: Peeling or deformation occurs, and dye discharge of the polarizer part occurs.

◯: Discharge of the polarizer part rarely occurred, but peeling or deformation did not occur.

⊚: Peeling, deformation, and dye discharge of the polarizer portion did not occur.

Optical properties after humidity test:

The degree of polarization and transmittance were measured for the laminated film before and after the humidity resistance test, and their deterioration (decrease from the value of the laminated film before the humidity resistance test) was evaluated.

^* For the denaturation (deformation, durability characteristics, optical characteristics) of the adherend material, deterioration occurs not only by heat but also by ultraviolet rays.

It can be seen from Table 2 that if the light is irradiated and cured after being heated to 40-70°C, the light-curable epoxy resin adhesive is fully cured, showing good adhesion, and there is almost no film deformation. On the other hand, when the heating temperature was 25° C. or 30° C., although there was no deformation of the film, the photocurable epoxy resin adhesive was insufficiently or uncured, and the adhesiveness was extremely poor. In addition, when the material temperature is 80 to 100° C. or higher, the photocurable epoxy resin adhesive is sufficiently cured and exhibits good adhesiveness, but the film is slightly warped. In addition, when the temperature exceeds 100°C, the photocurable epoxy resin adhesive is sufficiently cured and exhibits good adhesiveness, but the film is greatly denatured.

The same examination was performed on photocurable resins B to F, and although there were some differences in adhesiveness, the same results were obtained.

In addition, when heating is performed with a hot plate or hot air instead of an infrared lamp, a laminated film having the same performance as above can be obtained.

Manufacture of Laminated Films of Examples 7-13 and Comparative Examples 4-6

In the manufacture of the laminated films of Examples 1 to 6 and Comparative Examples 1 to 3, between the metal halide lamp and the adherend film, an optical filter (Aigraficus Corp. system), and irradiate light. In the same manner as in Examples 1 to 6 and Comparative Examples 1 to 3, laminated films of Examples 7 to 13 and Comparative Examples 4 to 6 were obtained, respectively.

[table 3]

Examples or comparative examples Material temperature (℃) The state of the adhesive after UV irradiation Deformation of film after UV irradiation Durability characteristics after humidity resistance test Optical properties after humidity test Comparative example 4 25 In liquid state, insufficient solidification none × - Comparative Example 5 30 In liquid state, insufficient solidification none × - Example 7 40 △ none △ somewhat worse Example 8 50 ○ none ○ slightly worse Example 9 60 ◎ none ◎ no change Example 10 70 ◎ none ◎ no change Example 11 80 ◎ none ◎ no change Example 12 100 ◎ none △ somewhat worse Example 13 120 ○ slightly warped △ somewhat worse Comparative example 6 140 ○ deformation × -

As can be seen from Table 3, if an optical filter with a cutoff wavelength below 390nm is arranged between the metal halide lamp and the adherend, then compared with the case where no configuration is made, the polarizer and the film will have less denaturation, and the optical filter with Laminated film with good adhesion and durability characteristics. Even if instead of a filter with a cutoff wavelength of 390nm or less, a filter with a cutoff wavelength of less than 320nm, a filter with a cutoff wavelength of less than 340nm, or a filter with a cutoff wavelength of less than 370nm can be used, the same result can be obtained. The use of filters below 390nm has the least effect on the constituent films. By using an optical filter, the deformation of the film when heated to 120°C can be suppressed, but the deformation of the film when heated to 140°C cannot be suppressed.

Production of Comparative Examples 7-12 Laminated Films

In the same manner as in Example 1, a film having a three-layer structure was obtained. The obtained 3-layer thin film was not heated, and a metal halide lamp (manufactured by Aigraficus Co., Ltd.) was used with an irradiation intensity of 500 mW/cm ² (405 nm) and an integrated light intensity of 500, 1000, 2000 and 3000 mJ/cm ² ( 405 nm), light irradiation was performed to obtain a laminated film. Furthermore, when the integrated light intensity is 2000 and 3000mJ/cm ² (405nm), an optical filter (Aigraficus) with a cutoff wavelength of 390nm or less placed between the metal halide lamp and the adherend film is used. Co., Ltd.) was irradiated with light to obtain a laminated film.

[Table 4]

Examples or comparative examples optical filter Cumulative UV light intensity (mJ/cm ² (405nm)) The state of the adhesive after UV irradiation Deformation of film after UV irradiation Comparative example 7 none 500 In liquid state, insufficient solidification none Comparative example 8 none 1000 In liquid state, insufficient solidification none Comparative example 9 none 2000 ○ deformation Comparative Example 10 have 2000 ○ deformation Comparative example 11 none 3000 ◎ deformation Comparative example 12 have 3000 ◎ deformation

As can be seen from Table 4, in the case where heating was not performed before light irradiation, a laminated film having excellent adhesiveness and no deformation of the film could not be obtained even if the amount of light irradiation was increased or decreased.

Industrial availability

The present invention can be used in the manufacture of laminated films used in a wide range of industrial fields including automobiles, aircraft, and electric and electronic devices. In addition, since it is a process of rapid curing and rapid adhesion, it greatly contributes to the improvement of the production speed and the reduction of the heating process.

Claims (4)

1. the manufacture method of a laminate film, it is to use the light-cured type epoxide resin adhesive to come the manufacture method of the laminate film that adhesive film forms, and it is characterized in that, comprising:

The light-cured type epoxide resin adhesive that will be present between film is heated to the temperature more than 40 ℃, thereby and described binding agent is carried out illumination penetrate and make its curing adhering film.

2. film adhering method, it is to use the light-cured type epoxide resin adhesive to come bonding polariscope film and protective film and/or optical compensating film and the adhering method of the film that forms, it is characterized in that, comprising:

To be present in light-cured type epoxide resin adhesive between film and heat, thereby and described binding agent be carried out illumination penetrate and make its curing adhering film to more than 40 ℃ and the temperature below the heat resisting temperature of described film.

3. method according to claim 1 and 2, wherein,

The described temperature of heating is 40～120 ℃.

4. according to any described method in the claim 1～3, wherein,

Light is the ultraviolet ray that at least a portion in the light of wavelength below 400nm is cut off.