WO2018174012A1 - Optical laminate - Google Patents

Abstract

Provided is an optical laminate which has excellent reworkability even if provided with a glass film. An optical laminate according to the present invention is sequentially provided with a glass film, a polarizer and an adhesive layer in this order, while having an adhesive power of 5 N/25 mm or less with respect to glass plates. In one embodiment of the present invention, the thickness of the adhesive layer is from 5 μm to 100 μm. In one embodiment of the present invention, the thickness of the glass film is from 20 μm to 200 μm.

Description

Optical laminate

The present invention relates to an optical laminate.

Conventionally, an image display device is manufactured by bonding a resin film including a polarizing plate to a substrate of a display element via an adhesive, and then further bonding glass on the resin film via an adhesive or an adhesive. . In the manufacture of such an image display device, if a bonding defect (misalignment of bonding position, entrapment of foreign matter, etc.) is found, the adhesive or adhesive between the glass and the resin film is frozen and cut. Then, the resin film is often peeled from the substrate of the display element. However, when such a peeling process is employed, the operation is complicated and complicated, resulting in a problem that the productivity of the image display device is deteriorated.

In recent years, image display devices are becoming lighter and thinner, and tend to be flexible, and it has been proposed to use an optical laminated body made of thinner glass (Patent Document 1). ). When it becomes necessary to peel off an optical laminate using thin glass, the freeze-cutting method as described above is difficult to adopt due to the fragility of the thin glass.

As described above, in an optical laminated body including glass, workability (reworkability) at the time of re-peeling after bonding to another member becomes a problem, and improvement of reworkability is required.

International Publication No. 2013-175767

The present invention has been made in order to solve the above-described conventional problems, and an object of the present invention is to provide an optical laminate having excellent reworkability while being provided with a glass film.

The optical layered body of the present invention includes a glass film, a polarizer, and a pressure-sensitive adhesive layer in this order, and the adhesive force to the glass plate is 5 N / 25 mm or less.
In one embodiment, the pressure-sensitive adhesive layer has a thickness of 5 μm to 100 μm.
In one embodiment, the glass film has a thickness of 20 μm to 200 μm.
In one embodiment, the pressure-sensitive adhesive layer contains a (meth) acrylic pressure-sensitive adhesive.
In one embodiment, the pressure-sensitive adhesive layer contains a urethane-based pressure-sensitive adhesive.
According to another aspect of the present invention, an image display device is provided. The image display device includes the optical laminate.
In one embodiment, the image display device includes the optical layered body on the outermost side on the viewing side.

According to the present invention, it is possible to provide an optical laminate that is excellent in reworkability while having a glass film.

It is a schematic sectional drawing of the optical laminated body by one Embodiment of this invention.

A. Overall configuration diagram 1 of the optical stack is a schematic sectional view of an optical laminate according to one embodiment of the present invention. The optical laminate 100 includes a glass film 10, a polarizer 20, and an adhesive layer 30 in this order. The optical laminate 100 may further include a protective film 40 that protects the polarizer 20 between the glass film 10 and the polarizer 20 as necessary. Moreover, although not shown in figure, you may arrange | position a protective film between the polarizer 20 and the adhesive layer 30 as needed. The glass film 10, the polarizer 20, and the protective film 40 can be bonded together through any appropriate pressure-sensitive adhesive or adhesive.

Since the optical laminated body 100 of the present invention includes the glass film 10, the hardness is high. Moreover, the optical laminated body 100 of this invention can prevent the damage of the glass film 10 by providing the polarizer 20 on the one side of the glass film 10, and is excellent in impact resistance. In the present invention, since the impact applied to the surface of the glass film 10 (surface opposite to the polarizer) can be effectively released to the polarizer 20 side, the impact resistance is excellent as described above. Conceivable. Further, the glass film 10 has a function of protecting the polarizer 20. That is, in the present invention, the glass film 10 and the polarizer 20 protect each other. Therefore, it is possible to reduce the number of protective members, and a lightweight and thin optical laminate can be obtained. Moreover, since the glass film 10 has high gas barrier property, deterioration of the polarizer 20 is prevented. Furthermore, since the glass film 10 has a small dimensional change, the expansion or contraction of the optical laminate 100 of the present invention is suppressed. As a result, it is possible to obtain the optical layered body 100 that has high durability and is prevented from peeling or floating.

The adhesive strength of the optical laminate of the present invention to the glass plate is preferably 5 N / 25 mm or less, more preferably 3 N / 25 mm or less, and even more preferably 1.5 N / 25 mm or less. In this specification, the adhesive strength is determined by bonding the optical layer of the optical laminate to the glass plate, and then peeling the optical laminate at a peel angle of 90 ° and a peel rate in an environment of a temperature of 23 ° C./humidity of 55%. Measured by peeling at 300 mm / min. A detailed measurement method will be described later.

The optical laminate of the present invention is excellent in reworkability because the adhesive strength to the glass plate is in the above range. More specifically, when the optical laminated body is bonded to an adherend (for example, a member constituting an image display device such as a display element substrate), any trouble (for example, misalignment, entrapment of foreign matter, etc.) If this occurs, the optical laminate needs to be peeled off. At this time, if the optical laminate has an adhesive strength to the glass plate within the above range, the glass film is prevented from being broken and easily peeled off from the adherend. can do.

The lower limit value of the adhesive strength of the optical laminate of the present invention to the glass plate is preferably 0.005 N / 25 mm or more, more preferably 0.01 N / 25 mm or more, and further preferably 0.1 N / 25 mm or more. is there. Within such a range, problems such as peeling and floating can be prevented even under high heat and / or high humidity.

The thickness of the optical laminate of the present invention is preferably 50 μm to 500 μm, more preferably 100 μm to 300 μm.

The optical layered body of the present invention may further include other layers. Examples of other layers include an antireflection layer, an antiglare layer, an antistatic layer, and a conductive layer. A separator may be disposed on the surface of the pressure-sensitive adhesive layer. The separator can protect the pressure-sensitive adhesive layer until the optical laminate is put into practical use.

The optical layered body of the present invention is suitably used for an image display device. More specifically, the optical layered body of the present invention can be used for a substrate of a display element of an image display device. In another aspect of the present invention, an image display device including the optical laminate is provided. In one embodiment, the optical layered body of the present invention may be arranged on the outermost side on the viewing side of the image display device. The optical layered body thus arranged can function as a front protective plate of the image display device.

B. Glass Film Any appropriate film can be adopted as the glass film. Examples of the glass film include soda-lime glass, borate glass, aluminosilicate glass, and quartz glass according to the classification according to the composition. Moreover, according to the classification | category by an alkali component, an alkali free glass and a low alkali glass are mentioned. The content of alkali metal components (for example, Na ₂ O, K ₂ O, Li ₂ O) in the glass is preferably 15% by weight or less, and more preferably 10% by weight or less.

The thickness of the glass film is preferably 20 μm to 200 μm, more preferably 50 μm to 150 μm. If it is such a range, the optical laminated body which is excellent in flexibility, and a glass film is hard to crack and is excellent in productivity can be obtained.

The light transmittance at a wavelength of 550 nm of the glass film is preferably 85% or more. The refractive index of the glass film at a wavelength of 550 nm is preferably 1.4 to 1.65.

The density of the glass film is preferably 2.3 g / cm ³ to 3.0 g / cm ³ , more preferably 2.3 g / cm ³ to 2.7 g / cm ³ . If it is a glass film of the said range, a lightweight optical laminated body will be obtained.

Any appropriate method can be adopted as the method for forming the glass film. Typically, the glass film is obtained by melting a mixture containing main raw materials such as silica and alumina, an antifoaming agent such as sodium nitrate and antimony oxide, and a reducing agent such as carbon at a temperature of 1400 ° C to 1600 ° C. Then, after forming into a thin plate shape, it is produced by cooling. Examples of the glass film forming method include a slot down draw method, a fusion method, and a float method. The glass film formed into a plate shape by these methods may be chemically polished with a solvent such as hydrofluoric acid, if necessary, in order to reduce the thickness or improve the smoothness.

C. Polarizer / protective film C-1. Polarizer The thickness of the polarizer is not particularly limited, and an appropriate thickness can be adopted depending on the purpose. The thickness is typically about 1 μm to 80 μm. In one embodiment, a thin polarizer is used, and the thickness of the polarizer is preferably 20 μm or less, more preferably 15 μm or less, further preferably 10 μm or less, and particularly preferably 6 μm or less. It is. By using such a thin polarizer, a thin optical laminate can be obtained.

The polarizer preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The single transmittance of the polarizer is preferably 40.0% or more, more preferably 41.0% or more, further preferably 42.0% or more, and particularly preferably 43.0% or more. The polarization degree of the polarizer is preferably 99.8% or more, more preferably 99.9% or more, and further preferably 99.95% or more.

Preferably, the polarizer is an iodine-based polarizer. More specifically, the polarizer may be composed of a polyvinyl alcohol resin (hereinafter referred to as “PVA resin”) film containing iodine.

Any appropriate resin can be adopted as the PVA resin for forming the PVA resin film. Examples thereof include polyvinyl alcohol and ethylene-vinyl alcohol copolymer. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. The ethylene-vinyl alcohol copolymer can be obtained by saponifying an ethylene-vinyl acetate copolymer. The degree of saponification of the PVA resin is usually 85 mol% to 100 mol%, preferably 95.0 mol% to 99.95 mol%, more preferably 99.0 mol% to 99.93 mol%. It is. The degree of saponification can be determined according to JIS K 6726-1994. By using a PVA-based resin having such a saponification degree, a polarizer having excellent durability can be obtained. If the degree of saponification is too high, there is a risk of gelation.

The average degree of polymerization of the PVA resin can be appropriately selected according to the purpose. The average degree of polymerization is usually 1000 to 10,000, preferably 1200 to 5000, and more preferably 1500 to 4500. The average degree of polymerization can be determined according to JIS K 6726-1994.

As a manufacturing method of the said polarizer, the method (I) of extending | stretching and dye | staining a PVA-type resin film single-piece | unit, and the method of extending | stretching and dye | staining the laminated body (i) which has a resin base material and a polyvinyl alcohol-type resin layer ( II) and the like. Since the method (I) is a well-known and commonly used method in the art, detailed description thereof is omitted. In the production method (II), preferably, a laminate (i) having a resin base material and a polyvinyl alcohol resin layer formed on one side of the resin base material is stretched and dyed, A step of producing a polarizer. The laminate (i) can be formed by applying and drying a coating liquid containing a polyvinyl alcohol-based resin on a resin substrate. The laminate (i) may be formed by transferring a polyvinyl alcohol-based resin film onto a resin base material. Details of the production method (II) are described in, for example, Japanese Patent Application Laid-Open No. 2012-73580, which is incorporated herein by reference.

C-2. Protective film Any appropriate resin film may be employed as the protective film. Examples of the protective film forming material include polyester resins such as polyethylene terephthalate (PET), cellulose resins such as triacetyl cellulose (TAC), cycloolefin resins such as norbornene resins, and olefins such as polyethylene and polypropylene. Examples thereof include resins and (meth) acrylic resins. Of these, polyethylene terephthalate (PET) is preferable. The “(meth) acrylic resin” refers to an acrylic resin and / or a methacrylic resin.

In one embodiment, a (meth) acrylic resin having a glutarimide structure is used as the (meth) acrylic resin. Examples of (meth) acrylic resins having a glutarimide structure (hereinafter also referred to as glutarimide resins) include, for example, JP-A-2006-309033, JP-A-2006-317560, JP-A-2006-328329, and JP-A-2006-328329. JP-A-2006-328334, JP-A-2006-337491, JP-A-2006-337492, JP-A-2006-337493, JP-A-2006-337569, JP-A-2007-009182, JP-A-2009- Nos. 161744 and 2010-284840. These descriptions are incorporated herein by reference.

The protective film and the polarizer are laminated via any appropriate adhesive layer. The resin base material used at the time of producing the polarizer can be peeled off before or after the protective film and the polarizer are laminated.

The thickness of the protective film is preferably 5 μm to 55 μm, more preferably 10 μm to 50 μm, and still more preferably 15 μm to 45 μm.

D. The thickness of the adhesive layer adhesive layer is preferably 5 [mu] m ~ 100 [mu] m, more preferably 10 [mu] m ~ 70 [mu] m. If it is in such a range, the adhesive strength is appropriately adjusted, the glass film is hardly broken at the time of peeling, it can be easily peeled off from the adherend, and the optical layer is excellent in the durability of the pressure-sensitive adhesive layer. You can get a body.

The pressure-sensitive adhesive layer contains any appropriate pressure-sensitive adhesive as long as the effects of the present invention can be obtained. Preferably, the pressure-sensitive adhesive layer contains a (meth) acrylic pressure-sensitive adhesive and / or a urethane pressure-sensitive adhesive. By using these pressure-sensitive adhesives, it is possible to obtain an optical laminate in which the adhesive force is appropriately adjusted and the glass film is hardly broken at the time of peeling.

D-1. (Meth) acrylic pressure-sensitive adhesive (meth) acrylic pressure-sensitive adhesive contains a (meth) acrylic polymer.

The content ratio of the (meth) acrylic polymer in the (meth) acrylic pressure-sensitive adhesive is preferably 40% by weight to 99.9% by weight, more preferably 50% by weight to 99.5% by weight, Preferably, it is 60 to 99% by weight.

(Meth) acrylic polymer is a polymer containing a (meth) acrylic monomer as a constituent monomer component. Only one type of (meth) acrylic polymer may be used, or two or more types may be used. Only one (meth) acrylic monomer may be used, or two or more may be used.

The (meth) acrylic polymer preferably contains (meth) acrylic acid alkyl ester as a monomer component constituting the polymer. Examples of (meth) acrylic acid alkyl esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, and hexyl. (Meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (Meth) acrylates having 1 to 18 carbon atoms such as (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate, etc. Glycol ester and the like. Among these, (meth) acrylic acid alkyl esters having an alkyl group having 4 to 13 carbon atoms are preferred, more preferably 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, and n-tridecyl (meth) acrylate. Only one (meth) acrylic acid alkyl ester may be used, or two or more may be used.

The content ratio of the (meth) acrylic acid alkyl ester to the total monomer components (100 wt%) constituting the (meth) acrylic polymer is preferably 70 wt% to 98 wt%, more preferably 80 wt% to 98 wt%. % By weight, more preferably 85% by weight to 98% by weight, and particularly preferably 90% by weight to 98% by weight.

The monomer component constituting the (meth) acrylic polymer may further contain a hydroxyl group-containing monomer. Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl ( (Meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl acrylate, N-methylol (meth) acrylamide, vinyl alcohol, allyl alcohol, 2- Examples thereof include hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether. Only one kind of hydroxyl group-containing monomer may be used, or two or more kinds thereof may be used.

The content ratio of the hydroxyl group-containing monomer to the total monomer component (100% by weight) constituting the (meth) acrylic polymer is preferably 0.1% by weight to 15% by weight, more preferably 0.5% by weight to It is 13% by weight, more preferably 0.5% by weight to 10% by weight, and particularly preferably 1% by weight to 8% by weight.

The monomer component constituting the (meth) acrylic polymer contains, for example, a polyfunctional monomer from the viewpoint that a crosslinked structure can be introduced into the (meth) acrylic polymer and appropriate cohesive force can be obtained. May be. Examples of the polyfunctional monomer include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and 1,6 hexanediol di (meta). ) Acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, divinylbenzene, N, N′-methylenebisacrylamide and the like. Only one type of polyfunctional monomer may be used, or two or more types may be used.

The content ratio of the polyfunctional monomer to the total monomer component (100 wt%) constituting the (meth) acrylic polymer is preferably 0.1 wt% to 30 wt%, more preferably 0.1 wt% to 10 wt%. % By weight. Within such a range, it is possible to obtain an optical laminate in which the adhesive strength is appropriately adjusted and the glass film is not particularly easily broken during peeling.

The monomer component constituting the (meth) acrylic polymer may further contain other monomers. Examples of other monomers include cyano group-containing monomers, vinyl ester monomers, aromatic vinyl monomers, amide group-containing monomers, imide group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, vinyl ether monomers, and N-acryloylmorpholine. Is mentioned. Among these, a cyano group-containing monomer, a vinyl ester monomer, and an aromatic vinyl monomer are preferable from the viewpoint of improving cohesion and heat resistance. From the viewpoint of improving adhesive strength and having a functional group that functions as a crosslinking point, amide group-containing monomers, imide group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, vinyl ether monomers, and N-acryloylmorpholine are preferred. Only one type of other monomer may be used, or two or more types may be used.

Examples of the cyano group-containing monomer include acrylonitrile and methacrylonitrile.

Examples of the vinyl ester monomer include vinyl esters such as vinyl acetate, vinyl propionate, and vinyl laurate.

Examples of the aromatic vinyl monomer include styrene, chlorostyrene, chloromethylstyrene, α-methylstyrene, and other substituted styrene.

Examples of amide group-containing monomers include acrylamide, methacrylamide, diethyl acrylamide, N-vinyl pyrrolidone, N, N-dimethyl acrylamide, N, N-dimethyl methacrylamide, N, N-diethyl acrylamide, N, N-diethyl methacryl. Examples thereof include amide, N, N′-methylenebisacrylamide, N, N-dimethylaminopropyl acrylamide, N, N-dimethylaminopropyl methacrylamide, and diacetone acrylamide.

Examples of the imide group-containing monomer include cyclohexylmaleimide, isopropylmaleimide, N-cyclohexylmaleimide, and itaconimide.

Examples of the amino group-containing monomer include aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, and the like.

Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, and allyl glycidyl ether.

Examples of the vinyl ether monomer include methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, and the like.

The content ratio of other monomers to the total monomer components (100% by weight) constituting the (meth) acrylic polymer is preferably 0 to 40% by weight, more preferably more than 0% by weight and 40% by weight or less. More preferably, it is more than 0% by weight and 35% by weight or less, and particularly preferably more than 0% by weight and 30% by weight or less.

The monomer component constituting the (meth) acrylic polymer has a carboxyl group-containing monomer, a sulfo group-containing monomer, a phosphate group-containing monomer, and an acid anhydride group-containing from the viewpoint of suppressing an increase in adhesion to an adherend. It is preferable that no monomer is contained. That is, it is preferable that the other monomer does not include a carboxyl group-containing monomer, a sulfo group-containing monomer, a phosphate group-containing monomer, and an acid anhydride group-containing monomer.

(Meth) acrylic polymer can be obtained by polymerizing monomer components constituting the (meth) acrylic polymer. Examples of the polymerization method include solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, photopolymerization (active energy ray polymerization), and the like. Among these, solution polymerization is preferable from the viewpoint of cost and productivity. The (meth) acrylic polymer to be obtained may be any of a random copolymer, a block copolymer, an alternating copolymer, a graft copolymer, and the like.

The weight average molecular weight of the (meth) acrylic polymer is preferably 100,000 to 5,000,000, more preferably 200,000 to 4,000,000, and further preferably 300,000 to 3,000,000.

The glass transition temperature (Tg) of the (meth) acrylic polymer is preferably 0 ° C. or lower, more preferably −10 ° C. or lower. The glass transition temperature (Tg) can be determined by the following formula, where the glass transition temperature of the homopolymer obtained from each monomer is Tgn (° C.).
1 / (Tg + 273) = Σ [Wn / (Tgn + 273)]
In the formula, Tg (° C.) is the glass transition temperature of the copolymer, Wn is the weight fraction of each monomer, Tgn (° C.) is the glass transition temperature of the homopolymer obtained from each monomer, and n is the type of each monomer. .

The (meth) acrylic pressure-sensitive adhesive may contain a cross-linking agent from the viewpoint that an appropriate cohesive force can be obtained. Examples of the crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, a melamine crosslinking agent, an aziridine crosslinking agent, and a metal chelate crosslinking agent. Among these, an isocyanate type crosslinking agent and an epoxy type crosslinking agent are preferable in that the effects of the present invention can be sufficiently exhibited. One type of crosslinking agent may be sufficient and 2 or more types may be sufficient as it.

Examples of the isocyanate-based crosslinking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate, and 2,4-tolylene diene. Isocyanates, aromatic isocyanates such as 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate, trimethylolpropane / tolylene diisocyanate trimer adduct (trade name “Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd.), trimethylolpropane / Hexamethylene diisocyanate trimer adduct (trade name “Coronate HL” manufactured by Nippon Polyurethane Industry Co., Ltd.), Isocyanate of hexamethylene diisocyanate Rate body (trade name "Coronate HX" manufactured by Nippon Polyurethane Industry Co., Ltd.), and the like isocyanate adducts such as.

Examples of the epoxy crosslinking agent include bisphenol A, epichlorohydrin type epoxy resin, ethylene glycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol glycidyl ether, and trimethylol. Propane triglycidyl ether, diglycidyl aniline, diamine glycidyl amine, N, N, N ′, N′-tetraglycidyl-m-xylenediamine (trade name “TETRAD-X” manufactured by Mitsubishi Gas Chemical Company), 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane (trade name “TETRAD-C” manufactured by Mitsubishi Gas Chemical Company, Inc.).

The amount of the crosslinking agent is preferably 0.01 to 15 parts by weight, more preferably 0.1 to 10 parts by weight, with respect to 100 parts by weight of the (meth) acrylic polymer. The amount is preferably 0.1 to 8 parts by weight, particularly preferably 0.5 to 5 parts by weight. By adjusting the blending amount of the cross-linking agent with respect to 100 parts by weight of the (meth) acrylic polymer within the above range, an optical laminate is obtained in which the adhesive force is appropriately adjusted and the glass film is not easily broken during peeling. be able to.

(Meth) acrylic pressure-sensitive adhesive may contain a crosslinking catalyst. Examples of the cross-linking catalyst include metal-based cross-linking catalysts (particularly tin-based cross-linking catalysts) such as tetra-n-butyl titanate, tetraisopropyl titanate, nasec ferric acid, butyl tin oxide, and dioctyl tin dilaurate. Only one type of crosslinking catalyst may be used, or two or more types may be used.

The amount of the crosslinking catalyst is preferably 0.001 to 0.05 parts by weight, more preferably 0.003 to 0.04 parts by weight per 100 parts by weight of the (meth) acrylic polymer. More preferably, it is 0.005 to 0.03 parts by weight.

(Meth) acrylic adhesive may contain a crosslinking retarder. Examples of the crosslinking retarder include β-ketoesters such as methyl acetoacetate, ethyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, lauryl acetoacetate, stearyl acetoacetate, acetylacetone, 2,4-hexanedione, benzoylacetone, etc. Β-diketone. Among these, acetylacetone is preferable in that the effects of the present invention can be sufficiently exhibited. Only one type of crosslinking retarder may be used, or two or more types may be used.

The amount of the crosslinking retarder is preferably 0.1 to 10 parts by weight, more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the (meth) acrylic polymer. More preferably, it is 0.1 to 3 parts by weight.

The (meth) acrylic pressure-sensitive adhesive contains additives such as a plasticizer, an anti-aging agent, a colorant (such as a pigment and a dye), an antistatic agent, and a tackifying resin as long as the effects of the present invention are not impaired. Also good. The (meth) acrylic pressure-sensitive adhesive may contain any appropriate solvent.

D-2. Urethane adhesive The urethane adhesive contains a polyurethane resin.

The polyurethane resin content in the urethane pressure-sensitive adhesive is preferably 40% by weight to 99% by weight, more preferably 50% by weight to 95% by weight, and still more preferably 60% by weight to 90% by weight. is there.

Only one type of polyurethane resin may be used, or two or more types may be used.

The polyurethane resin can be obtained by reacting the polyol (A) with the polyfunctional isocyanate compound (B).

As a polyol (A), only 1 type may be sufficient and 2 or more types may be sufficient.

Examples of the polyol (A) include polyester polyol, polyether polyol, polycaprolactone polyol, polycarbonate polyol, and castor oil-based polyol.

Polyester polyol can be obtained, for example, by an esterification reaction between a polyol component and an acid component.

Examples of the polyol component include ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1 , 3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl -1,8-octanediol, 1,8-decanediol, octadecanediol, glycerin, trimethylolpropane, pentaerythritol, hexanetriol, polypropylene glycol and the like.

Examples of the acid component include succinic acid, methyl succinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, 1,14-tetradecanedioic acid, dimer acid, 2-methyl-1, 4-cyclohexanedicarboxylic acid, 2-ethyl-1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, acid anhydrides thereof Etc.

Examples of polyether polyols include water, low molecular weight polyols (propylene glycol, ethylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc.), bisphenols (bisphenol A, etc.), dihydroxybenzenes (catechol, resorcin, hydroquinone, etc.), etc. And polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide. Specific examples include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like.

Examples of the polycaprolactone polyol include caprolactone-based polyester diols obtained by ring-opening polymerization of cyclic ester monomers such as ε-caprolactone and σ-valerolactone.

Examples of the polycarbonate polyol include a polycarbonate polyol obtained by polycondensation reaction of the polyol component and phosgene; the polyol component, dimethyl carbonate, diethyl carbonate, diprovir carbonate, diisopropyl carbonate, dibutyl carbonate, ethyl butyl carbonate, ethylene carbonate, Polycarbonate polyol obtained by ester exchange condensation with carbonic acid diesters such as propylene carbonate, diphenyl carbonate and dibenzyl carbonate; copolymerized polycarbonate polyol obtained by using two or more of the above polyol components in combination; Polycarbonate polyol obtained by esterification reaction with a compound; the above-mentioned various polycarbonate polyols and a hydroxyl group-containing compound; Polycarbonate polyol obtained by etherification reaction; polycarbonate polyol obtained by transesterification of the various polycarbonate polyols and ester compounds; polycarbonate polyol obtained by transesterification of the various polycarbonate polyols and hydroxyl group-containing compounds; And polyester polycarbonate polyols obtained by polycondensation reaction of the various polycarbonate polyols with dicarboxylic acid compounds; copolymer polyether polycarbonate polyols obtained by copolymerizing the various polycarbonate polyols and alkylene oxides;

Examples of castor oil-based polyol include castor oil-based polyol obtained by reacting castor oil fatty acid with the above polyol component. Specific examples include castor oil-based polyols obtained by reacting castor oil fatty acid with polypropylene glycol.

In one embodiment, a polyol (triol) having three OH groups is used as the polyol (A). When triol is used, an optical laminate can be obtained in which the adhesive force is appropriately adjusted and the glass film is hardly broken at the time of peeling. The content ratio of the polyol (triol) having 3 OH groups in the polyol (A) is preferably 50% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, and still more preferably. It is 80 to 100% by weight, more preferably 90 to 100% by weight, particularly preferably 95 to 100% by weight, and most preferably substantially 100% by weight.

The polyol (A) preferably contains a polyol having a number average molecular weight Mn of 400 to 20000. The content ratio of the polyol having a number average molecular weight Mn of 400 to 20000 in the polyol (A) is preferably 50% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, and still more preferably. It is 90% to 100% by weight, particularly preferably 95% to 100% by weight, and most preferably substantially 100% by weight.

In one embodiment, when a polyol (triol) having three OH groups is used as the essential component as the polyol (A), a triol having a number average molecular weight Mn of 7000 to 20000 and a number average molecular weight Mn of 2000 to 6000 are used. And a triol having a number average molecular weight Mn of 400 to 1900, more preferably a triol having a number average molecular weight Mn of 8000 to 15000, a triol having a number average molecular weight Mn of 2000 to 5000, and a number average molecular weight. A triol having a Mn of 500 to 1800, more preferably a triol having a number average molecular weight Mn of 8000 to 12000, a triol having a number average molecular weight Mn of 2000 to 4000, and a triol having a number average molecular weight Mn of 500 to 1500 And in combination. When these three types of triols are used in combination, the adhesive strength is appropriately adjusted, and an optical laminate that is particularly difficult to break the glass film at the time of peeling can be obtained.

1 type of polyfunctional isocyanate compounds (B) may be sufficient, and 2 or more types may be sufficient as them.

As the polyfunctional isocyanate compound (B), any suitable polyfunctional isocyanate compound that can be used for the urethanization reaction can be adopted. Examples of such a polyfunctional isocyanate compound (B) include polyfunctional aliphatic isocyanate compounds, polyfunctional alicyclic isocyanate compounds, polyfunctional aromatic isocyanate compounds, and the like.

Examples of the polyfunctional aliphatic isocyanate compound include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4,4 Examples include 4-trimethylhexamethylene diisocyanate.

Examples of the polyfunctional alicyclic isocyanate compound include 1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, Examples include hydrogenated tolylene diisocyanate and hydrogenated tetramethylxylylene diisocyanate.

Examples of the polyfunctional aromatic diisocyanate compound include phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2 ′ monodiphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4 Examples include '-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, and xylylene diisocyanate.

Examples of the polyfunctional isocyanate compound (B) include trimethylolpropane adducts of various polyfunctional isocyanate compounds as described above, burettes reacted with water, and trimers having an isocyanurate ring. These may be used in combination.

In the polyol (A) and the polyfunctional isocyanate compound (B), the equivalent ratio of the NCO group to the OH group is more than 1.0 and not more than 5.0 as the NCO group / OH group, preferably 1.1 to 5.0, more preferably 1.2 to 4.0, still more preferably 1.5 to 3.5, and particularly preferably 1.8 to 3.0.

The polyurethane-based pressure-sensitive adhesive preferably contains a deterioration preventing agent such as an antioxidant, an ultraviolet absorber, and a light stabilizer. Only one type of deterioration preventing agent may be used, or two or more types may be used. As the deterioration preventing agent, an antioxidant is particularly preferable.

In addition, the urethane-based pressure-sensitive adhesive can contain any appropriate other component as long as the effects of the present invention are not impaired. Examples of such other components include other resin components other than polyurethane resins, tackifiers, inorganic fillers, organic fillers, metal powders, pigments, foils, softeners, plasticizers, and anti-aging agents. Agents, conductive agents, ultraviolet absorbers, antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents and the like.

Urethane adhesive may contain a modified silicone oil.

When the urethane pressure-sensitive adhesive contains a modified silicone oil, the content ratio is preferably 0.001 to 50 parts by weight, more preferably 0.01 parts by weight to 100 parts by weight of the polyurethane resin. 40 parts by weight, more preferably 0.01 parts by weight to 30 parts by weight, particularly preferably 0.01 parts by weight to 20 parts by weight, and most preferably 0.01 parts by weight to 10 parts by weight. .

As the modified silicone oil, any appropriate modified silicone oil can be adopted as long as the effects of the present invention are not impaired. Examples of such modified silicone oil include modified silicone oil available from Shin-Etsu Chemical Co., Ltd. The modified silicone oil is preferably a polyether-modified silicone oil. Examples of the polyether-modified silicone oil include a side chain-type polyether-modified silicone oil and a both-end-type polyether-modified silicone oil.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. In Examples, unless otherwise specified, “parts” and “%” are based on weight.

[Production Example 1] Production of Polarizer A Amorphous polyethylene terephthalate (hereinafter also referred to as “PET”) (IPA copolymerized PET) film (thickness: 100 μm) having 7 mol% of isophthalic acid unit as a thermoplastic resin substrate. ) And the surface was subjected to corona treatment (58 W / m ² / min). On the other hand, acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name: Gohsephimer Z200 (average polymerization degree: 1200, saponification degree: 98.5 mol%, acetoacetylation degree: 5 mol%)) A PVA added with 1 wt% (polymerization degree 4200, saponification degree 99.2%) was prepared, and a coating solution of PVA aqueous solution with a PVA resin of 5.5 wt% was prepared, and the film thickness after drying was 12 μm. And dried for 10 minutes by hot air drying in an atmosphere of 60 ° C. to prepare a laminate in which a PVA resin layer was provided on the substrate.
Next, this laminate was first stretched 1.8 times in air at 130 ° C. (air-assisted stretching) to produce a stretched laminate. Next, a step of insolubilizing the PVA layer in which the PVA molecules contained in the stretched laminate were oriented was performed by immersing the stretched laminate in a boric acid insolubilized aqueous solution having a liquid temperature of 30 ° C. for 30 seconds. The boric acid insolubilized aqueous solution in this step had a boric acid content of 3 parts by weight with respect to 100 parts by weight of water. A colored laminate was produced by dyeing this stretched laminate. In the colored laminate, the stretched laminate is applied to a dye solution containing iodine and potassium iodide at a liquid temperature of 30 ° C. so that the single transmittance of the PVA layer constituting the finally produced polarizer is 40 to 44%. The PVA layer contained in the stretched laminate is dyed with iodine by immersing it in an arbitrary time. In this step, the staining solution was prepared using water as a solvent and an iodine concentration in the range of 0.1 to 0.4% by weight and a potassium iodide concentration in the range of 0.7 to 2.8% by weight. The concentration ratio of iodine and potassium iodide is 1 to 7. Next, the colored laminated body was immersed in a 30 ° C. boric acid crosslinking aqueous solution for 60 seconds to perform a crosslinking treatment between PVA molecules of the PVA layer on which iodine was adsorbed. The boric acid crosslinking aqueous solution in this step had a boric acid content of 3 parts by weight with respect to 100 parts by weight of water and a potassium iodide content of 3 parts by weight with respect to 100 parts by weight of water.
Furthermore, the obtained colored laminate was stretched in a boric acid aqueous solution at a stretching temperature of 70 ° C. and stretched 3.05 times in the same direction as the stretching in the air (boric acid-water stretching), and finally An optical film laminate having a draw ratio of 5.50 was obtained. The optical film laminate was removed from the boric acid aqueous solution, and the boric acid adhering to the surface of the PVA layer was washed with an aqueous solution having a potassium iodide content of 4 parts by weight with respect to 100 parts by weight of water. The washed optical film laminate was dried by a drying process using hot air at 60 ° C. The thickness of the polarizer A contained in the obtained optical film laminate was 5 μm.

[Production Example 2] Production of polarizer B A polyvinyl alcohol film having a thickness of 60 μm is stretched up to 3 times while being dyed in an iodine solution of 0.3% concentration at 30 ° C. for 1 minute between rolls having different speed ratios. did. Thereafter, the total draw ratio was stretched to 6 times while being immersed in an aqueous solution containing 60% at 4% concentration of boric acid and 10% concentration of potassium iodide for 0.5 minutes. Next, after washing by immersing in an aqueous solution containing potassium iodide at 30 ° C. and 1.5% concentration for 10 seconds, drying was performed at 50 ° C. for 4 minutes to obtain a polarizer B having a thickness of 22 μm.

[Production Example 3] Production of (meth) acrylic pressure-sensitive adhesive A 200 parts by weight of 2-ethylhexyl acrylate and 10-hydroxyethyl acrylate 10 in a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube and a condenser Part by weight, 0.4 part by weight of 2,2′-azobisisobutyronitrile and 312 parts by weight of ethyl acetate as a polymerization initiator were charged, nitrogen gas was introduced while gently stirring, and the liquid temperature in the flask was adjusted to 65. The polymerization reaction was carried out for about 6 hours while maintaining the temperature at around 0 ° C. to prepare a (meth) acrylic polymer solution (A1) having a weight average molecular weight of 500,000.
To the obtained (meth) acrylic polymer solution (A1) (solid content: 100 parts by weight), 0.6 parts by weight of isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name: Coronate HX) as a crosslinking agent. Then, 0.6 parts by weight of dibutyltin dilaurate (1% by weight ethyl acetate solution) as a crosslinking catalyst and 0.1 parts by weight of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM403) are added at 25 ° C. The (meth) acrylic pressure-sensitive adhesive A was prepared by mixing and stirring for about 1 minute while maintaining the vicinity.

[Production Example 4] Production of (meth) acrylic pressure-sensitive adhesive B In the (meth) acrylic polymer solution (A1) (solid content 100 parts by weight) produced in Production Example 3, isocyanurate of hexamethylene diisocyanate as a crosslinking agent. (Product name: Coronate HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) 1.0 part by weight, dibutyltin dilaurate (1% by weight ethyl acetate solution) as a crosslinking catalyst, 0.6 part by weight, silane coupling agent (Shin-Etsu Chemical Co., Ltd.) (Product name: KBM403) 0.1 part by weight was blended to prepare (meth) acrylic adhesive B.

[Production Example 5] Production of urethane-based pressure-sensitive adhesive C As polyol (A), triol (manufactured by Asahi Glass Co., Ltd., trade name: Preminol S3011, Mn = 10000): 85 parts by weight, triol (manufactured by Sanyo Chemical Co., Ltd., Sanniks) GP-3000, Mn = 3000): 13 parts by weight, triol (manufactured by Sanyo Chemical Co., Ltd., trade name: Sannix GP-1000, Mn = 1000): 2 parts by weight are used as the polyfunctional isocyanate compound (B). Functional alicyclic isocyanate compound (Nippon Polyurethane Industry Co., Ltd., trade name: Coronate HX): 18 parts by weight, Catalyst (manufactured by Nippon Chemical Industry Co., Ltd., trade name: Nursem Ferric): 0.04 parts by weight, deterioration Irganox 1010 (manufactured by BASF) as an inhibitor: 0.50 part by weight, fatty acid ester (isopropyl myristate) Pill, manufactured by Kao, trade name: Exepal IPM, Mn = 270): 30 parts by weight, 1-ethyl-3-methylimidazolium bis (fluoromethanesulfonyl) imide (Daiichi Kogyo Seiyaku Co., Ltd., trade name: AS110): 1.5 parts by weight, double-ended polyether-modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., KF-6004): 0.01 parts by weight, ethyl acetate: 241 parts by weight as a diluent solvent, and stirred with a disper As a result, urethane pressure-sensitive adhesive C was obtained.

[Production Example 6] Production of (meth) acrylic pressure-sensitive adhesive D In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube and a condenser, 99 parts by weight of butyl acrylate and 1 weight of 4-hydroxybutyl acrylate Then, 0.1 part by weight of 2,2′-azobisisobutyronitrile as a polymerization initiator was charged together with 100 parts by weight of ethyl acetate, and nitrogen gas was introduced with gentle stirring, followed by substitution with nitrogen. A polymerization reaction was carried out for 8 hours while maintaining the liquid temperature at around 55 ° C. to prepare a (meth) acrylic polymer solution (A2) having a weight average molecular weight of 1,600,000.
With respect to the obtained (meth) acrylic polymer solution (A2) (solid content: 100 parts by weight), an isocyanate crosslinking agent (manufactured by Mitsui Takeda Chemical Co., Ltd., trade name: Takenate D110N, trimethylolpropane xylylene diisocyanate) 0.1 A (meth) acrylic pressure-sensitive adhesive D was prepared by blending 1 part by weight of a polyether compound (manufactured by Asahi Glass Urethane Co., Ltd., trade name: Excestar 2420).

[Production Example 7] Production of (meth) acrylic pressure-sensitive adhesive E With respect to the (meth) acrylic polymer solution (A2) (solid content 100 parts by weight) prepared in Production Example 6, an isocyanate crosslinking agent (Mitsui Takeda Chemical Co., Ltd.) Product name: Takenate D110N, trimethylolpropane xylylene diisocyanate 0.3 parts by weight, silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM403) 0.1 parts by weight, A (meth) acrylic pressure-sensitive adhesive E was prepared.

[Production Example 8] Production of (meth) acrylic pressure-sensitive adhesive F In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube and a condenser, 100 parts by weight of butyl acrylate, 3 parts by weight of acrylic acid, 2 -1 part by weight of hydroxyethyl acrylate and 0.1 part by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator were added together with 100 parts by weight of ethyl acetate, and nitrogen gas was introduced while gently stirring to replace the nitrogen. After that, the polymerization temperature was kept at around 55 ° C. for 8 hours, and a (meth) acrylic polymer solution (A3) having a weight average molecular weight of 1.8 million was prepared.
With respect to the obtained (meth) acrylic polymer solution (A3) (solid content 100 parts by weight), an isocyanate crosslinking agent (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name: Coronate L, adduct of tolylene diisocyanate of trimethylolpropane) ) 0.5 part by weight, 0.1 part by weight of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM403) was blended to prepare (meth) acrylic pressure-sensitive adhesive F.

[Example 1]
A glass film (manufactured by Nippon Electric Glass Co., Ltd., trade name: OA10, size: 400 mm × 40 mm, thickness: 100 μm), protective film (40 μm thick acrylic resin film), and polarizer A in this order are adhesives To obtain a laminate a.
The (meth) acrylic adhesive A was applied to the silicone-treated surface of a polyethylene terephthalate film having a silicone treatment on one side, and heated at 110 ° C. for 3 minutes to form an adhesive layer A having a thickness of 25 μm. The pressure-sensitive adhesive layer A was transferred to the polarizer A side of the laminate a to obtain an optical laminate A.

[Example 2]
(Production of optical laminate)
A glass film (manufactured by Nippon Electric Glass Co., Ltd., trade name: OA10, size: 400 mm × 40 mm, thickness: 100 μm) and polarizer A were bonded together with an adhesive to obtain a laminate b.
The (meth) acrylic adhesive A was applied to the silicone-treated surface of a polyethylene terephthalate film having a silicone treatment on one side, and heated at 110 ° C. for 3 minutes to form an adhesive layer A having a thickness of 25 μm. The pressure-sensitive adhesive layer A was transferred to the polarizer A side of the laminate b to obtain an optical laminate B.

[Example 3]
Glass film (manufactured by Nippon Electric Glass Co., Ltd., trade name: OA10, size: 400 mm × 40 mm, thickness: 100 μm), protective film (40 μm thick acrylic resin film), polarizer B, protective film (thickness) 40 μm acrylic resin film) was laminated in this order via an adhesive to obtain a laminate c.
The (meth) acrylic adhesive A was applied to the silicone-treated surface of a polyethylene terephthalate film having a silicone treatment on one side, and heated at 110 ° C. for 3 minutes to form an adhesive layer A having a thickness of 25 μm. The pressure-sensitive adhesive layer A was transferred to the polarizer B side of the laminate c to obtain an optical laminate C.

[Example 4]
In the same manner as in Example 1, a laminate a was obtained.
The (meth) acrylic adhesive B was applied to the silicone-treated surface of the polyethylene terephthalate film subjected to silicone treatment and heated at 110 ° C. for 3 minutes to form an adhesive layer B having a thickness of 12 μm. The pressure-sensitive adhesive layer B was transferred to the polarizer A side of the laminate a to obtain an optical laminate D.

[Example 5]
In the same manner as in Example 1, a laminate a was obtained.
Urethane pressure-sensitive adhesive C was applied to the silicone-treated surface of a polyethylene terephthalate film having a silicone treatment on one side, and heated at 110 ° C. for 3 minutes to form a pressure-sensitive adhesive layer C having a thickness of 25 μm. The pressure-sensitive adhesive layer C was transferred to the polarizer A side of the laminate a to obtain an optical laminate E.

[Example 6]
In the same manner as in Example 1, a laminate a was obtained.
The (meth) acrylic adhesive D was applied to the silicone-treated surface of the polyethylene terephthalate film subjected to silicone treatment, and heated at 110 ° C. for 3 minutes to form an adhesive layer D having a thickness of 25 μm. The pressure-sensitive adhesive layer D was transferred to the polarizer A side of the laminate a to obtain an optical laminate F.

[Example 7]
In the same manner as in Example 1, a laminate a was obtained.
(Meth) acrylic pressure-sensitive adhesive E was applied to the silicone-treated surface of a polyethylene terephthalate film subjected to silicone treatment, and heated at 110 ° C. for 3 minutes to form a pressure-sensitive adhesive layer E having a thickness of 50 μm. The pressure-sensitive adhesive layer E was transferred to the polarizer A side of the laminate a to obtain an optical laminate G.

[Comparative Example 1]
In the same manner as in Example 1, a laminate a was obtained.
The (meth) acrylic pressure-sensitive adhesive F was applied to a silicone-treated surface of a polyethylene terephthalate film subjected to silicone treatment, and heated at 110 ° C. for 3 minutes to form a pressure-sensitive adhesive layer F having a thickness of 25 μm. The pressure-sensitive adhesive layer F was transferred to the polarizer A side of the laminate a to obtain an optical laminate H.

[Comparative Example 2]
An optical laminate I was obtained in the same manner as in Example 1 except that the glass film was changed to a polyethylene terephthalate film having a thickness of 100 μm.

<Evaluation>
The optical laminates obtained in the examples and comparative examples were subjected to the following evaluation. The results are shown in Table 1.

1. Adhesive strength The optical laminate was cut into 150 mm × 25 mm, and attached to a non-alkali glass plate having a thickness of 0.7 mm (product name: EG-XG) using a laminator, and then 50 ° C. A sample for evaluation was produced by autoclaving at 5 atm for 15 minutes to ensure complete adhesion.
Using the tensile tester (Autograph SHIMAZU AG-1 10KN), the optical laminate was removed from the glass plate using the tensile tester (autograph SHIMAZU AG-1 10KN) under the conditions of 23 ° C./humidity 55%, peeling angle 90 °, peeling speed 300 mm / min. It peeled and the adhesive force of the optical laminated body was measured. The measurement was sampled at an interval of 1 time / 0.5 s, and the average value was taken as the measurement value.

2. Reworkability The optical laminate was attached to non-alkali glass (trade name: EG-XG, manufactured by Corning) having a size of 15 inches (diagonal line) with a thickness of 0.7 mm using a laminator. Next, autoclaving was performed at 50 ° C. and 0.5 MPa for 15 minutes, and the optical laminate was brought into close contact with the acrylic-free glass to prepare a sample for evaluation.
About the said sample for evaluation, the optical laminated body was peeled from the glass in the diagonal direction from one corner of the optical laminated body, and the crack of the glass film and the fracture | rupture were evaluated.
A: The optical laminate has no cracks and can be easily reworked. ○: The optical laminate has slight cracks but can be easily reworked. There is no practical problem.
(Triangle | delta): Although an optical laminated body has a crack, it can rework without fracture | rupture. There is no practical problem.
×: Rework is not possible because the optical laminate breaks

3. Durability test The optical laminate was bonded to non-alkali glass (EG-XG manufactured by Corning, Inc.) having a size of 15 inches (diagonal line) with a thickness of 0.7 mm using a laminator. Next, autoclaving was performed at 50 ° C. and 0.5 MPa for 15 minutes, and the optical laminate was brought into close contact with the acrylic-free glass to prepare a sample for evaluation.
After the sample for evaluation was treated in an atmosphere of 80 ° C. for 500 hours (heating test), the appearance was visually evaluated according to the following criteria.
Further, the sample for evaluation was treated for 500 hours in an atmosphere of 60 ° C./90% RH (humidification test), and then the appearance was visually evaluated according to the following criteria.
A: No change in appearance such as foaming or peeling.
○: Slightly peeled off or foamed at the end, but no problem in practical use.
Δ: There is peeling or foaming at the end, but there is no practical problem unless it is a special use.
X: Remarkably peeled off at the end, causing practical problems.

 

DESCRIPTION OF SYMBOLS 10 Glass film 20 Polarizer 30 Adhesive layer 100 Optical laminated body

Claims (7)

1. A glass film, a polarizer, and an adhesive layer are provided in this order,
   The adhesive force to the glass plate is 5 N / 25 mm or less,
   Optical laminate.
2. 2. The optical laminate according to claim 1, wherein the pressure-sensitive adhesive layer has a thickness of 5 μm to 100 μm.
3. 2. The optical laminate according to claim 1, wherein the glass film has a thickness of 20 μm to 200 μm.
4. The optical laminate according to claim 1, wherein the pressure-sensitive adhesive layer contains a (meth) acrylic pressure-sensitive adhesive.
5. The optical laminate according to claim 1, wherein the pressure-sensitive adhesive layer contains a urethane-based pressure-sensitive adhesive.
6. An image display device comprising the optical laminate according to claim 1.
7. The image display device according to claim 6, comprising the optical laminate on the outermost side on the viewing side.
   
   
   

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