TW201715006A - Adhesive layer for optical members, adhesive layer-provided optical member, and image display device - Google Patents

Abstract

A purpose of the present invention is to provide an adhesive layer for optical members, which can be used to attach large and thin optical members or uneven optical members to each other, and which has a light diffusing function. Another purpose of the present invention is to provide: an adhesive layer-provided optical member having at least one layer of the adhesive layer for optical members, on at least one surface of the optical member; and an image display device including the adhesive layer-provided optical member. The adhesive layer for optical members is characterized by: being formed of a base adhesive composition containing a (meth)acrylic polymer and light diffusing particles; including at least one layer of a light diffusing adhesive layer having a thickness of 5-300 [mu]m; having an overall thickness of 20 [mu]m or more; and having a haze of 10-96%.

Description

Adhesive layer for optical member, optical member with adhesive layer, and image display device

FIELD OF THE INVENTION The present invention relates to an optical member for an optical member having a light diffusing function and an optical member having an adhesive layer of at least one layer of the optical member adhesive layer on at least one surface of the optical member. Further, the present invention relates to an image display device including the optical member with the above-mentioned adhesive layer.

Background of the Invention In recent years, in order to increase the size and thickness of a video display device such as a liquid crystal display device, there is a similar demand for each optical member constituting the image display device. When such a large-sized and thinned optical member is fixed and laminated by an adhesive, it is easy to cause a poor bonding (wrinkle or distortion) in the optical member, and as a result, there is a defect in the display portion. .

Moreover, the backlight module of the image display device generally includes a diffusion sheet to improve visibility, but sometimes the diffusion sheet cannot ensure sufficient visibility, and the adhesive sheet having a light diffusing function is used with the diffusion sheet. situation.

As such a light-diffusing adhesive, there has been disclosed a light-diffusing adhesive comprising: an adhesive containing a base polymer, and light-diffusing fine particles having a lower refractive index than the adhesive, and the base polymer contains (A) The (meth)acrylic polymer contains a (meth)acrylic monomer containing an aromatic ring as a monomer unit (for example, see Patent Document 1). Advanced technical literature

Patent Document 1: Japanese Patent Publication No. 2014-224964

Disclosure of the Invention Problems to be Solved by the Invention Although the adhesive layer of Patent Document 1 has a light diffusing function, wrinkles or bulging may occur when various optical members which have been enlarged and thinned are attached. Further, for example, when an optical member having a step (concavity and convexity) on the surface of a ruthenium sheet is bonded, it is necessary to have a level difference absorbing property. However, the pressure-sensitive adhesive layer of Patent Document 1 is not sufficient in terms of height difference absorption.

Accordingly, an object of the present invention is to provide an adhesive layer for an optical member which can be bonded to various optical members having a large-sized thinned film or optical members having a height difference, and has a light diffusing function. Further, an object of the present invention is to provide an optical member having an adhesive layer having at least one layer of the above-mentioned optical member adhesive layer on at least one side of an optical member, and an image display device including the optical member having the above-mentioned adhesive layer. Means to solve the problem

The inventors of the present invention have intensively studied in order to solve the above problems, and as a result, have found the following transparent resin layer, and have completed the present invention.

That is, the present invention relates to an adhesive layer for an optical member characterized by comprising at least one light-diffusing adhesive layer having a thickness of 5 to 300 μm, and the light-diffusing adhesive layer is composed of a (meth)acrylic polymer. The base adhesive composition and the light diffusing fine particles are formed, and the thickness of the entire adhesive layer is 20 μm or more and the haze is 10 to 96%.

The light diffusing fine particles are preferably polyoxynized resin fine particles.

The refractive index of the light diffusing fine particles is preferably lower than the refractive index of the base adhesive composition.

The volume average particle diameter of the light diffusing fine particles is preferably 1 to 5 μm.

The adhesive layer of the present invention may be formed by laminating a transparent adhesive layer having a haze of 0.01 to 5% on at least one surface of the light-diffusing adhesive layer, and the thickness of the light-diffusing adhesive layer is preferably 5 to 30 μm. The thickness of the transparent adhesive layer of 0.01 to 5% is preferably 50 to 300 μm.

The content of the light diffusing fine particles in the light diffusing adhesive layer is preferably from 3 to 30% by weight.

The (meth)acrylic polymer preferably contains an alkyl (meth)acrylate and a carboxyl group-containing monomer as a monomer component.

The transparent adhesive layer preferably contains a (meth)acrylic polymer containing an alkyl (meth)acrylate, a hydroxyl group-containing monomer, and a nitrogen-containing monomer as a monomer component.

The (meth)acrylic polymer contained in the transparent adhesive layer preferably does not contain a carboxyl group-containing monomer as a monomer component.

Further, the present invention relates to an optical member with an adhesive layer, characterized in that at least one layer of the optical member has at least one layer of the above-mentioned adhesive member for an optical member. Furthermore, the present invention relates to an image display apparatus characterized by comprising the optical member with the above-mentioned adhesive layer. Effect of the invention

Since the adhesive layer for an optical member of the present invention has a light-diffusing adhesive layer having a specific thickness and the entire adhesive layer has a specific thickness, it is possible to laminate various optical members which have been enlarged and thinned without wrinkles or swelling. Further, since the pressure-sensitive adhesive layer for an optical member of the present invention has a specific thickness, even when a member having a level difference such as a ruthenium sheet is bonded to the surface, the height can be adjusted without any gap. . Moreover, since the adhesive layer for optical members of the present invention has a specific haze, it is also excellent in display unevenness or durability required for the adhesive layer for optical members. The optical display member using the adhesive layer of the adhesive layer for an optical member of the present invention and the image display device including the optical member having the adhesive layer have high reliability.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The adhesive layer for an optical member of the present invention is characterized in that it comprises at least one light-diffusing adhesive layer having a thickness of 5 to 300 μm, and the light-diffusing adhesive layer is composed of The base adhesive composition of the (meth)acrylic polymer and the light diffusing fine particles are formed, and the thickness of the entire adhesive layer is 20 μm or more and the haze is 10 to 96%.

The structure of the adhesive layer for an optical member of the present invention is not particularly limited as long as it has at least one light-diffusing adhesive layer having a thickness of 5 to 300 μm and the entire thickness of the adhesive layer is 20 μm or more. The specific structure is not particularly limited, but may be, for example, the following structure.

When the thickness of the light-diffusing adhesive layer is less than 20 μm, the transparent adhesive layer other than the light-diffusing adhesive layer may be bonded to the light-diffusing adhesive layer so that the total thickness becomes 20 μm or more, thereby forming the present invention. The optical member is an adhesive layer. In this case, the light-diffusing adhesive layer or the transparent adhesive layer other than the layer may be one layer or two or more layers. For example, as shown in FIG. 1(a), the light-diffusing adhesive layer 2 may be used. The transparent adhesive layer 3 forms an adhesive layer 1 for an optical member. Further, as shown in FIG. 1(b), a transparent adhesive layer 3 may be formed on both surfaces of the light-diffusing adhesive layer 2, or the light-diffusing adhesive layer 2 and the transparent adhesive layer may be formed as shown in FIG. 1(c). 3 interactive layers. Further, even when the thickness of the light-diffusing adhesive layer is 20 μm or more, the same form as in Figs. 1(a) to 1(c) can be obtained, but as shown in Fig. 1(d), only The one-layer light-diffusing adhesive layer 2 is used as the adhesive layer 1 for an optical member of the invention. In addition, in FIGS. 1(a) to 1(d), the separator 4 is bonded to both surfaces of the adhesive member layer 1 for optical members.

1. Adhesive Layer for Optical Member The thickness of the entire adhesive layer of the adhesive layer for an optical member of the present invention is preferably 20 μm or more, more preferably 30 μm or more, more preferably 50 μm or more, still more preferably 100 μm or more, and even more preferably 100 μm or more. When the thickness of the entire adhesive layer is 20 μm or more, even if the optical member as the adherend is a member having a height difference on the surface such as a sheet, it can be bonded without any gap along the height difference. It is appropriate. Further, the upper limit of the overall thickness of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 300 μm or less, and more preferably 200 μm or less.

(1) Light-diffusing adhesive layer The light-diffusing adhesive layer contained in the adhesive layer for optical members of the present invention is formed of a base adhesive composition containing a (meth)acrylic polymer and light-diffusing fine particles. The thickness is 5~300μm.

(1-1) Substrate Adhesive Composition The base adhesive composition used in the present invention contains a (meth)acrylic polymer (A) as a base polymer. The (meth)acrylic polymer (A) contains an alkyl (meth)acrylate (a1) constituting the main skeleton of the (meth)acrylic polymer (A) as a monomer unit. Further, (meth) acrylate means acrylate and/or methacrylate.

The alkyl (meth)acrylate (a1) may be a compound having a linear or branched chain of 1 to 18 carbon atoms. For example, as the alkyl group, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, cyclohexyl, heptyl, 2-ethylhexyl, isooctyl can be exemplified. , fluorenyl, fluorenyl, isodecyl, dodecyl, isotetradecyl, lauryl, thirteen, fifteen, sixteen, seventeen, eighteen, and the like. They can be used singly or in combination.

The blending ratio of the alkyl (meth)acrylate (a1) is preferably 50% by weight or more based on the total constituent monomer (100% by weight) of the (meth)acrylic polymer (A), 50~ 100% by weight is preferred, 60 to 100% by weight is more preferred, and 70 to 90% by weight is particularly preferred.

The (meth)acrylic polymer (A) preferably contains a carboxyl group-containing monomer (a2), a hydroxyl group-containing monomer (a3), and a nitrogen-containing monomer for the purpose of improving adhesion and heat resistance. (a4) One or more monomers in the group formed as a monomer component.

In the case of the carboxyl group-containing monomer (a2), those having a polymerizable functional group and having a carboxyl group can be used without particular limitation, and the polymerizable functional group is an unsaturated double such as a (meth) acrylonitrile group or a vinyl group. The functional group of the bond. The carboxyl group-containing monomer may, for example, be (meth)acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, croton. Acid, isocroic acid, etc., etc., can be used individually or in combination. Anaconic acid or maleic acid can be used as an acid anhydride. Among them, acrylic acid and methacrylic acid are preferred, and acrylic acid is preferred.

The blending ratio of the carboxyl group-containing monomer (a2) is preferably 10% by weight or less based on the total constituent monomer (100% by weight) of the (meth)acrylic polymer (A), and is 0.05 to 10% by weight. Preferably, it is preferably 0.1 to 10% by weight, more preferably 0.5 to 5% by weight.

The hydroxyl group-containing monomer (a3) can be used without any particular limitation, and has a polymerizable functional group and has a hydroxyl group, and the polymerizable functional group is an unsaturated double bond such as a (meth)acryl fluorenyl group or a vinyl group. The hydroxyl group-containing monomer may, for example, be 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, or (meth)acrylic acid-4. - Hydroxybutyl ester, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, -12-hydroxy (meth)acrylate A hydroxyalkyl cycloalkyl (meth)acrylate such as a hydroxyalkyl (meth) acrylate such as lauryl ester or a (4-hydroxymethylcyclohexyl)methyl (meth)acrylate. Further, examples thereof include hydroxyethyl (meth) acrylamide, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether. They can be used singly or in combination. Among them, a hydroxyalkyl (meth) acrylate is preferred, and 2-hydroxyethyl (meth) acrylate is preferred.

The blending ratio of the hydroxyl group-containing monomer (a3) is preferably 20% by weight or less based on the total constituent monomer (100% by weight) of the (meth)acrylic polymer (A), and is 0.05 to 20% by weight. Preferably, 0.1 to 15% by weight is more preferred, and 1 to 15% by weight is particularly preferred.

The nitrogen-containing monomer (a4) can be used without any particular limitation, and has a polymerizable functional group and a functional group having a nitrogen atom, and the polymerizable functional group is unsaturated with a (meth)acryl fluorenyl group or a vinyl group. Double key. The nitrogen-containing monomer (a4) may, for example, be (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N- Isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, a (meth) acrylamide-based monomer such as (meth)acryl fluorenyl orolin; for example, ethyl (meth) acrylate, N, N-dimethylamine ethyl (meth) acrylate, (a) a monomer having a grade 1, 2 or 3 amine group at the end; such as a cyano group-containing monomer such as acrylonitrile or methacrylonitrile; N-vinylpyrrolidone; Pyrrolidone-based monomers such as N-(1-methylvinyl)pyrrolidone; others such as N-vinylpyridine, N-vinylpyridine, N-vinylpyrimidine, N-vinylpiperone , N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-ethylene a vinyl-containing heterocyclic compound such as azole or N-vinyl orolin; a phthalic acid amide compound such as N-ethyleneacetamide; for example, N-cyclohexylmaleimide, N-isopropylmalanium a maleimide monomer such as an imine, N-lauryl maleimide or N-phenylmaleimide; for example, N-methyl Ikonide, N-ethyl Ikon Yttrium imine, N-butyliconazole, N-octyl Icinoimine, N-2-ethylhexylkamponium imine, N-cyclohexylkkonium imine, N-laurel Ikonideimine monomer such as carbitol imine; for example, N-(methyl)propenyloxymethylene succinimide, N-(methyl)propenyl-6-oxy A succinimide monomer such as hexamethylene succinimide, N-(methyl) propylene decyl-8-oxy octamethylene succinimide; others such as 2-(meth) acrylonitrile A sulfonic acid group-containing (meth) acrylamide monomer such as amine-2-methylpropanesulfonic acid or (meth) acrylamide propylenesulfonic acid, diacetone acrylamide or the like. Among them, a vinyl group-containing heterocyclic compound is preferred, and N-vinylpyrrolidone is preferred.

The blending ratio of the nitrogen-containing monomer (a4) is preferably 20% by weight or less based on the total constituent monomer (100% by weight) of the (meth)acryl-based polymer (A), and is 0.05 to 20% by weight. Preferably, 0.1 to 15% by weight is more preferred, and 1 to 15% by weight is particularly preferred.

In the (meth)acrylic polymer (A), the (meth)acrylic acid alkyl ester (a1), the carboxyl group-containing monomer (a2), the hydroxyl group-containing monomer (a3), and the nitrogen-containing monomer (a4) are contained. In addition, a polymerizable functional group having an unsaturated double bond such as a (meth) acrylonitrile group or a vinyl group may be further introduced by copolymerization to introduce one or more kinds of comonomers for the purpose of improving the adhesion and heat resistance. Specific examples of such comonomers include, for example, caprolactone adducts of acrylic acid; styrenesulfonic acid or allylsulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloxynaphthalene. a sulfonic acid group-containing monomer such as a sulfonic acid; a phosphate group-containing monomer such as 2-hydroxyethyl acryloylphosphoryl phosphate; and the like.

Further, as the modifying monomer, a vinyl monomer such as vinyl acetate or vinyl propionate; an epoxy group-containing acrylic monomer such as glycidyl (meth)acrylate; and polyethylene glycol (methyl group) may be used. a diol-based acrylate monomer such as acrylate, polypropylene glycol (meth) acrylate, methoxyethylene glycol (meth) acrylate or methoxypolypropylene glycol (meth) acrylate; tetrahydrofuran methyl ( An acrylate monomer such as a methyl acrylate, a fluorinated (meth) acrylate, a polyfluorene (meth) acrylate or a 2-methoxyethyl acrylate. Further, isoprene, butadiene, isobutylene, vinyl ether or the like can be mentioned.

Further, examples of the copolymerizable monomer other than the above may be a decane-based monomer containing a ruthenium atom. Examples of the decane-based monomer include 3-propenyloxypropyltriethoxydecane, vinyltrimethoxydecane, vinyltriethoxydecane, 4-vinylbutyltrimethoxydecane, and 4 -vinylbutyltriethoxydecane, 8-vinyloctyltrimethoxydecane, 8-vinyloctyltriethoxydecane, 10-oxodecyltrimethoxydecane, 10-propenyloxime Trimethoxy decane, 10-methyl propylene fluorenyl methoxy decyl triethoxy decane, 10-propenyl fluorenyl decyl triethoxy decane, and the like.

Further, in order to adjust the cohesive force of the adhesive, the monofunctional monomer may be a polyfunctional monomer as a comonomer. In this aspect, in the present invention, the monofunctional monomer is a monomer having one polymerizable functional group and the polymerizable functional group has an unsaturated double bond such as a (meth) acrylonitrile group or a vinyl group; The polyfunctional monomer is a monomer having at least two polymerizable functional groups as described later, and the polymerizable functional group has an unsaturated double bond such as a (meth)acryl fluorenyl group or a vinyl group.

The polyfunctional monomer is a monomer having at least two polymerizable functional groups and the polymerizable functional group has an unsaturated double bond such as a (meth) acrylonitrile group or a vinyl group, and examples thereof include (poly) ethylene. Alcohol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol III (meth) acrylate, dipentaerythritol hexa(meth) acrylate, 1,2-ethanediol di(meth) acrylate, 1,6-hexanediol di(meth) acrylate, Polyhydric alcohols such as 1,12-dodecanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethanetri(meth)acrylate, and (methyl) Acrylate ester compound; allyl (meth) acrylate, vinyl (meth) acrylate, divinyl benzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyl di (methyl) ) acrylate, hexyl di(meth) acrylate, and the like. The polyfunctional monomer may be used alone or in combination of two or more.

The ratio of the carboxyl monomer (a2), the hydroxyl group-containing monomer (a3), and the comonomer other than the nitrogen-containing monomer (a4) is not particularly limited, but constitutes the (meth)acrylic polymer (A). The total monomer is preferably 10% by weight or less, more preferably 0.1 to 10% by weight, still more preferably 0.1 to 5% by weight.

The (meth)acrylic polymer (A) can be obtained by appropriately combining and polymerizing according to the intended properties and desired properties. The obtained (meth)acrylic polymer (A) may be any of a random copolymer, a block copolymer, a graft copolymer and the like. The (meth)acrylic polymer (A) can be synthesized by any appropriate method. For example, it can be synthesized by referring to the publication of the Japanese book (share) and the former "Kyoto Kagaku".

For example, the polymerization method of the (meth)acrylic polymer (A) may employ any appropriate method. Specific examples thereof include solution polymerization, bulk polymerization, emulsion polymerization, and various radical polymerizations.

The polymerization initiator, the chain transfer agent, the emulsifier, and the like used in the radical polymerization can be appropriately selected and used without particular limitation. Further, the weight average molecular weight of the (meth)acrylic polymer can be controlled by the amount of the polymerization initiator, the chain transfer agent used, and the reaction conditions, and the amount thereof can be appropriately adjusted depending on the type thereof.

For example, in solution polymerization or the like, a polymerization solvent such as ethyl acetate, toluene or the like can be used. As a specific example of solution polymerization, the reaction is carried out by adding a polymerization initiator under an inert gas stream such as nitrogen, and reacting at a reaction temperature of usually about 50 to 70 ° C for about 5 to 30 hours.

The thermal polymerization initiator which can be used for solution polymerization or the like can be, for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, 2,2'-azodi (2-methylpropionic acid) dimethyl ester, 4, 4'-azobis-4-cyanojimic acid, azobisisovaleronitrile, 2,2'-azobis(2-carboxamidopropane Dihydrochloride, 2, 2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride, 2, 2'-azobis(2- Methyl propyl hydrazine) disulfate, 2, 2'-azobis(N, N'-dimethylene isobutyl hydrazine), 2, 2'-azobis[N-(2-carboxyethyl) An azo initiator such as -2-methylpropionamidine hydrate (manufactured by Wako Pure Chemical Industries, Ltd., VA-057); persulfate such as potassium persulfate or ammonium persulfate, and di(2-ethylhexyl) Peroxydicarbonate, bis(4-t-butylcyclohexyl)peroxydicarbonate, di-tert-butylperoxydicarbonate, tert-butylperoxy neodecanoate, third hexyl Oxytrimethyl acetate, tert-butylperoxytrimethyl acetate, dilauroyl peroxide, di-n-octyl peroxy, 1,1,3,3-tetramethylbutylperoxy 2-ethylhexanoate, bis(4-methylbenzhydryl) peroxide Dibenzoyl peroxide, tert-butylperoxy isobutyrate, 1,1-di(t-hexylperoxy)cyclohexane, tert-butyl hydroperoxide, hydrogen peroxide, etc. a peroxide-based initiator; a combination of a persulfate and a sodium hydrogen sulfite; a combination of a peroxide and a sodium ascorbate; a redox-based initiator obtained by combining a peroxide with a reducing agent; Limited to this.

The polymerization initiator may be used singly or in combination of two or more kinds, and it is preferably about 1 part by weight or less based on 100 parts by weight of the total monomer component of the (meth)acryl-based polymer (A). It is preferably from 0.005 to 1 part by weight, more preferably from 0.02 to 0.5 part by weight.

In another example, when the (meth)acrylic polymer (A) is produced by using, for example, 2,2'-azobisisobutyronitrile as a polymerization initiator, polymerization is carried out with respect to 100 parts by weight of the total amount of the monomer components. The amount of the initiator to be used is preferably about 0.2 parts by weight or less, more preferably about 0.06 to 0.2 parts by weight.

As the chain transfer agent, for example, lauryl mercaptan, propylene oxide thiol, hydrazine acetic acid, 2-hydrazine ethanol, thioglycolic acid, thioglycolic acid 2-ethylhexyl ester, 2,3-difluorene may be mentioned. -1-propanol and the like. The chain transfer agent may be used singly or in combination of two or more kinds, but the total content is about 0.1 part by weight or less based on 100 parts by weight of the total amount of the monomer components.

Further, examples of the emulsifier used in the emulsion polymerization include sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, ammonium polyoxyethylene alkyl ether sulfate, and polyoxyethylene alkylphenyl ether. Nonionic emulsifier such as an anionic emulsifier such as sodium sulfate, a polyoxyethylene alkyl ether, a polyoxyethylene alkylphenyl ether, a polyoxyethylene fatty acid ester, or a polyoxyethylene-polyoxypropylene block polymer Wait. These emulsifiers may be used alone or in combination of two or more.

A reactive emulsifier into which a radical polymerizable functional group such as a propenyl group or an allyl ether group is introduced can also be used. Specifically, for example, Aqualon HS-10, HS-20, KH-10, BC-05, BC-10, BC-20 (all of which are manufactured by First Industrial Pharmaceutical Co., Ltd.), Ade Gallia Soap SE10N (made by Adeka Co., Ltd.) )Wait.

The amount of the emulsifier used is preferably 5 parts by weight or less, more preferably 0.3 to 5 parts by weight, per 100 parts by weight of the total of the monomer components, and particularly preferably 0.5 from the viewpoints of polymerization stability and mechanical stability. ~1 parts by weight.

Further, when the (meth)acrylic polymer (A) is produced by radiation polymerization, the polymer can be obtained by polymerizing the monomer component by irradiation with an electron beam or a radiation such as UV (ultraviolet rays). When the radiation polymerization is carried out by the electron beam, it is not particularly necessary to contain the photopolymerization initiator in the monomer component. However, when the radiation polymerization is carried out by ultraviolet polymerization, the polymerization time can be shortened, and the like. The monomer component contains a photopolymerization initiator. The photopolymerization initiator may be used alone or in combination of two or more.

The photopolymerization initiator is not particularly limited as long as it is a substance capable of initiating photopolymerization, and a generally used photopolymerization initiator can be used. For example, a benzoin ether photopolymerization initiator, an acetophenone photopolymerization initiator, an α-keto alcohol photopolymerization initiator, an aromatic sulfonium chloride photopolymerization initiator, and a photoactive oxime photopolymerization can be used. Initiator, benzoin-based photopolymerization initiator, diphenylethylenedione-based photopolymerization initiator, benzophenone-based photopolymerization initiator, ketal-based photopolymerization initiator, 9-oxo-sulfur A photopolymerization initiator, a mercaptophosphine oxide photopolymerization initiator, etc.

Specifically, the benzoin ether photopolymerization initiator may, for example, be benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenyl. Ethyl ethyl ketone [trade name: IRGACURE 651, manufactured by BASF Corporation] and anisole methyl ether. The acetophenone-based photopolymerization initiator may, for example, be 1-hydroxycyclohexyl phenyl ketone [trade name: IRGACURE 184, manufactured by BASF Corporation], 4-phenoxydichloroacetophenone, 4-tert-butyl-di Chloroacetophenone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one [trade name: IRGACURE 2959, manufactured by BASF Corporation] 2-hydroxy-2-methyl-1-phenyl-propan-1-one [trade name: DAROCUR 1173, manufactured by BASF Corporation], methoxyacetophenone or the like. The α-keto alcohol-based photopolymerization initiator may, for example, be 2-methyl-2-hydroxypropionylbenzene or 1-[4-(2-hydroxyethyl)-phenyl]-2-hydroxy-2-methylpropane. -1-ketone and the like. The aromatic sulfonium chloride-based photopolymerization initiator may, for example, be 2-naphthalenesulfonium chloride or the like. The photoactive oxime-based photopolymerization initiator may, for example, be 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-ruthenium or the like.

Further, the benzoin-based photopolymerization initiator contains, for example, benzoin or the like. The diphenylethylenedione-based photopolymerization initiator contains, for example, diphenylethylenedione or the like. The benzophenone-based photopolymerization initiator contains, for example, benzophenone, benzamidine benzoic acid, 3,3 ́-dimethyl-4-methoxybenzophenone, polyvinyl benzophenone, --hydroxycyclohexyl phenyl ketone and the like. The ketal-based photopolymerization initiator contains, for example, benzyldimethylketal or the like. 9-oxygen sulfur a photopolymerization initiator containing, for example, 9-oxosulfur 2-chloro-9-oxosulfur 2-methyl-9-oxosulfur 2,4-dimethyl-9-oxosulfur Isopropyl-9-oxosulfur 2,4-dichloro-9-oxosulfur 2,4-diethyl-9-oxosulfur Isopropyl-9-oxosulfur 2,4-diisopropyl-9-oxosulfur Dodecyl-9-oxosulfur Wait.

The mercaptophosphine-based photopolymerization initiator can be, for example, bis(2,6-dimethoxybenzylidene)phenylphosphine oxide, bis(2,6-dimethoxybenzylidene) (2) ,4,4-trimethylpentyl)phosphine oxide, bis(2,6-dimethoxybenzylidene)-n-butylphosphine oxide, bis(2,6-dimethoxybenzamide Mercapto)-(2-methylpropan-1-yl)phosphine oxide, bis(2,6-dimethoxybenzylidene)-(1-methylpropan-1-yl)phosphine oxide, Bis(2,6-dimethoxybenzylidene)-t-butylphosphine oxide, bis(2,6-dimethoxybenzylidene)cyclohexylphosphine oxide, double (2,6 -dimethoxybenzimidyl)octylphosphine oxide, bis(2-methoxybenzylidene)(2-methylpropan-1-yl)phosphine oxide, bis(2-methoxy (Benzyl indenyl) (1-methylpropan-1-yl)phosphine oxide, bis(2,6-diethoxybenzhydryl)(2-methylpropan-1-yl)phosphine oxide, Bis(2,6-diethoxybenzhydryl)(1-methylpropan-1-yl)phosphine oxide, bis(2,6-dibutoxybenzylidene) (2-methyl) Prop-1-yl)phosphine oxide, bis(2,4-dimethoxybenzylidene)(2-methylpropan-1-yl)phosphine oxide, bis(2,4,6-trimethyl) (Bestimido) (2,4-dipentyloxyphenyl) phosphine oxide, (2,6-dimethoxybenzimidyl)benzylphosphine oxide, bis(2,6-dimethoxybenzylidene)-2-phenylpropylphosphine oxide, double (2, 6-dimethoxybenzimidyl)-2-phenylethylphosphine oxide, bis(2,6-dimethoxybenzylidene)benzylphosphine oxide, bis(2,6-di Methoxybenzylidene)-2-phenylpropylphosphine oxide, bis(2,6-dimethoxybenzylidene)-2-phenylethylphosphine oxide, 2,6-di Methoxy benzhydryl benzyl butyl phosphine oxide, 2,6-dimethoxybenzimidyl benzyl octylphosphine oxide, bis(2,4,6-trimethylbenzhydryl) -2,5-diisopropylphenylphosphine oxide, bis(2,4,6-trimethylbenzylidene)-2-methylphenylphosphine oxide, bis(2,4,6 -trimethyl benzhydryl)-4-methylphenylphosphine oxide, bis(2,4,6-trimethylbenzylidene)-2,5-diethylphenylphosphine oxide, Bis(2,4,6-trimethylbenzylidene)-2,3,5,6-tetramethylphenylphosphine oxide, bis(2,4,6-trimethylbenzylidene) -2,4-di-n-butoxyphenylphosphine oxide, 2,4,6-trimethylbenzimidyldiphenylphosphine oxide, bis(2,6-dimethoxybenzylidene) )-2,4,4-trimethylpentylphosphine oxide, double (2 ,4,6-trimethylbenzylidene)isobutylphosphine oxide, 2,6-dimethoxybenzhydryl-2,4,6-trimethylbenzylidene-n-butyl Phosphonium oxide, bis(2,4,6-trimethylbenzylidene)phenylphosphine oxide, bis(2,4,6-trimethylbenzylidene)-2,4-dibutoxy Phenylphosphine oxide, 1,10-bis[bis(2,4,6-trimethylbenzylidene)phosphine oxide]decane, tris(2-methylbenzhydryl)phosphine oxide and many more.

The amount of the photopolymerization initiator to be used is not particularly limited. For example, it is preferably 0.01 to 5 parts by weight, based on 100 parts by weight of the total monomer constituting the (meth)acryl-based polymer (A), and 0.05 to 3 parts by weight. Preferably, it is preferably 0.05 to 1.5 parts by weight, more preferably 0.1 to 1 part by weight. When the amount of the photopolymerization initiator used is within the above range, the polymerization reaction can be sufficiently carried out. In addition, the photopolymerization initiator may be used singly or in combination of two or more.

The (meth)acrylic polymer (A) used in the present invention preferably has a weight average molecular weight of 400,000 to 2,500,000 and preferably 600,000 to 2,200,000. By making the weight average molecular weight more than 400,000, the durability of the adhesive layer can be satisfied, and the cohesive force of the adhesive layer can be suppressed to reduce the occurrence of residual glue. In addition, the weight average molecular weight is a value calculated by gel permeation chromatography (GPC) and calculated by polystyrene conversion. Moreover, it is difficult to measure the molecular weight of the (meth)acrylic polymer obtained by radiation polymerization.

The base adhesive composition used in the present invention may also contain a crosslinking agent. The crosslinking agent may, for example, be an organic crosslinking agent or a polyfunctional metal chelate compound. The organic crosslinking agent may, for example, be an isocyanate crosslinking agent, a peroxide crosslinking agent, an epoxy crosslinking agent, or an imide crosslinking agent. The polyfunctional metal chelate is a substance in which a polyvalent metal is covalently bonded or coordinately bonded to an organic compound. Examples of the polyvalent metal include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, and Ti. The organic compound may, for example, be an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound or a ketone compound. The atom which can be covalently bonded or coordinately bonded to the organic compound may, for example, be an oxygen atom. Among them, an isocyanate crosslinking agent is preferably used as the crosslinking agent.

The isocyanate type crosslinking agent is typically a compound having two or more isocyanate groups in one molecule. For example, isocyanate monomers such as toluene diisocyanate, chlorophenyl diisocyanate, tetramethylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, and the like areocyanate monomers. An isocyanate compound or a trimeric isocyanate compound or a biuret type compound which is added with trimethylolpropane or the like, and also with a polyether polyol or a polyester polyol, an acrylic polyol, a polybutadiene polyol An urethane prepolymer type isocyanate obtained by addition reaction of a polyisoprene polyol or the like. More preferably, the polyisocyanate compound is selected from the group consisting of hexamethylene isocyanate, hydrogenated xylylene diisocyanate, and isophorone diisocyanate, or a polyisocyanate compound derived therefrom. Here, one or a polyisocyanate compound selected from the group consisting of hexamethylene isocyanate, hydrogenated xylylene diisocyanate, and isophorone diisocyanate includes: hexamethylene isocyanate , hydrogenated xylylene diisocyanate, isophorone diisocyanate, polyol modified hexamethylene isocyanate, polyol modified hydrogenated xylylene diisocyanate, terpolymer hydrogenated xylylene diisocyanate, and polyol modification A heterochromone diisocyanate or the like.

The epoxy-based crosslinking agent is typically a compound having two or more epoxy groups (epoxypropyl groups) in one molecule. The epoxy crosslinking agent can be, for example, ethylene glycol diepoxypropyl ether, propylene glycol diepoxypropyl ether, diglycidyl terephthalate, spiroglycerol diepoxypropyl ether, diepoxypropyl Aminomethylcyclohexane, tetraethoxypropylxylenediamine, polyepoxypropylm-xylenediamine, and the like.

The peroxide may be any suitable compound capable of performing a crosslinking reaction of a base polymer by heating or illuminating to generate a radical active. If the workability and stability are considered, it is preferable to use a peroxide having a one-minute half-life temperature of 80 ° C to 160 ° C, and a peroxide of 90 ° C to 140 ° C is preferred. Specific examples of the peroxide include bis(2-ethylhexyl)peroxydicarbonate (1 minute half-life temperature: 90.6 ° C) and bis(4-t-butylcyclohexyl)peroxydicarbonate ( 1 minute half-life temperature: 92.1 ° C), dibutyl peroxydicarbonate (1 minute half-life temperature: 92.4 ° C), peroxy neodecanoic acid tert-butyl ester (1 minute half-life temperature: 103.5 ° C), peroxygen Third hexyl butyrate (1 minute half-life temperature: 109.1 ° C), third butyl peroxy isobutyrate (1 minute half-life temperature: 110.3 ° C), dilauroyl peroxide (1 minute half-life temperature: 116.4 ° C) ), di-n-octyl peroxide (1 minute half-life temperature: 117.4 ° C), 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate (1 minute half-life temperature: 124.3 ° C) , bis(4-methylbenzylidene) peroxide (1 minute half-life temperature: 128.2 ° C), dibenzyl hydrazino peroxide (1 minute half-life temperature: 130.0 ° C), tert-butyl peroxyisobutyric acid Ester (1 minute half-life temperature: 136.1 ° C), 1,1-di(trihexylperoxy)cyclohexane (1 minute half-life temperature: 149.2 ° C), and the like. Further, the half-life of the peroxide is an index indicating the decomposition rate of the peroxide, and means the time until the residual amount of the peroxide becomes half. Therefore, the 1-minute half-life temperature of the peroxide means a temperature at which the residual amount of the peroxide becomes half in 1 minute. The decomposition temperature for achieving the half-life at any time, and the half-life time at any temperature are described in the manufacturer's catalogue, etc., for example, in the "Organic Peroxide Catalogue" of the Japanese Oils and Fats Co., Ltd. (May 2003)" and so on.

The amount of the crosslinking agent to be used is preferably 0.01 to 20 parts by weight, and preferably 0.03 to 10 parts by weight, per 100 parts by weight of the (meth)acryl-based polymer (A). When the amount of the crosslinking agent used is less than 0.01 part by weight, the cohesive force of the adhesive tends to be insufficient, and there is a case where foaming occurs upon heating. When the amount of the crosslinking agent used exceeds 20 parts by weight, the moisture resistance is insufficient and peeling is likely to occur.

The base adhesive composition may also contain any suitable additives. The additive may, for example, be an antistatic agent, an antioxidant or a coupling agent. The types, addition amounts, and combinations of the additives can be appropriately set depending on the purpose.

The content of the base adhesive composition in the light-diffusing adhesive layer used in the present invention is preferably from 50 to 99.7% by weight, more preferably from 52 to 97% by weight, still more preferably from 70 to 97% by weight.

The refractive index of the base adhesive composition is preferably 1.47 or more, more preferably 1.47 to 1.60, and more preferably 1.47 to 1.55. When the refractive index of the base adhesive composition is within the above range, the difference in refractive index between the light-diffusing fine particles described later can be made into a desired range. As a result, it is preferable to obtain a light-diffusing adhesive layer having a desired haze value after hardening.

(1-2) Light-diffusing fine particles The light-diffusing adhesive layer is one in which light-diffusing fine particles are dispersed in an adhesive layer formed of the above-mentioned base adhesive composition. As the light-diffusing fine particles, any suitable substance can be used as long as the effects of the present invention can be obtained. Specific examples thereof include inorganic fine particles and polymer fine particles, and among them, polymer fine particles are preferred.

The material of the polymer fine particles may, for example, be a polyoxyn resin, a methacrylic resin (for example, polymethyl methacrylate), a polystyrene resin, a polyurethane resin, or a melamine resin. These resins have excellent dispersibility to the above-mentioned base adhesive composition and a suitable refractive index difference from the above-mentioned base adhesive composition, so that a light-diffusing adhesive layer excellent in diffusing performance can be obtained. Among them, polyoxymethylene resin and polymethyl methacrylate are particularly preferred.

The shape of the light diffusing fine particles may be, for example, a spherical shape, a flat shape, or an irregular shape. The light-diffusing fine particles may be used singly or in combination of two or more.

The light-diffusing fine particles used in the present invention preferably have a lower refractive index than the above-mentioned base adhesive composition. The refractive index of the light diffusing fine particles is preferably 1.30 to 1.70, and preferably 1.40 to 1.65. If the refractive index of the light diffusing fine particles is in the above range, the difference in refractive index between the light diffusing fine particles and the base adhesive composition can be made into a desired range, and as a result, a light diffusing adhesive layer having a desired haze value after hardening can be obtained. Therefore, it is appropriate.

The absolute value of the refractive index difference between the light diffusing fine particles and the underlying adhesive composition is preferably more than 0 and 0.2 or less, preferably more than 0 and 0.15 or less, more preferably 0.01 to 0.13.

The volume average particle diameter of the light diffusing fine particles is preferably about 1 to 5 μm, preferably about 2 to 5 μm, more preferably about 2 to 4 μm. When the volume average particle diameter of the light-diffusing fine particles is within the above range, it is preferable to obtain a light-diffusing adhesive layer having a desired haze value by combining with the above-mentioned base adhesive composition. Further, the volume average particle diameter can be measured, for example, using an ultracentrifugal automatic particle size distribution measuring apparatus.

The content of the light-diffusing fine particles in the light-diffusing adhesive layer is not particularly limited, but is preferably 0.3 to 50% by weight, preferably 3 to 48% by weight, more preferably 3 to 30% by weight. By making the blending amount of the light-diffusing fine particles into the above range, a light-diffusing adhesive layer having excellent light diffusing properties can be obtained.

(1-3) Method of Forming Light-Diffusing Adhesive Layer The light-diffusing adhesive layer can be formed, for example, by a method of dispersing light-diffusing fine particles in the base adhesive composition to form a light-diffusing adhesive. The object is coated on a support, and a solvent or the like is removed by drying. When the light-diffusing adhesive composition is applied, one or more solvents may be appropriately added. Further, when the base adhesive composition is an active energy ray-curable type, the light-diffusing adhesive layer can be formed by forming the base adhesive composition of the polymerized portion of the prepolymer. The light-diffusing fine particles are dispersed in the prepolymer to form a light-diffusing adhesive composition, which is applied onto a support, and the coated layer is irradiated with an active energy ray such as ultraviolet rays to form a light-diffusing adhesive layer. Further, the light-diffusing adhesive composition may be directly applied to an optical member such as a polarizing film to be described later to form a light-diffusing adhesive layer.

The light-diffusing adhesive layer has a thickness of 5 to 300 μm, preferably 5 to 250 μm, preferably 50 to 250 μm, more preferably 100 to 200 μm, and more preferably 100 μm or more and 200 μm or less. When the thickness of the light-diffusing adhesive layer is within the above range, it is preferable to bond the fine unevenness of the material to be bonded or the uneven portion for providing optical function. Further, when the transparent adhesive layer is bonded to the light-diffusing adhesive layer, the light-diffusing adhesive layer is not affected by the influence of the physical properties of the light-diffusing adhesive on the bonding effect of the peripheral member. The thickness is preferably about 5 to 100 μm, and preferably about 5 to 30 μm. When the light-diffusing adhesive layer is composed of two or more layers, the total thickness of all the light-diffusing adhesive layers may be within the above range.

Various methods can be used for the coating method of the light-diffusing adhesive composition. Specific examples thereof include roll coating, contact roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roller coating, bar coating, blade coating, air knife coating, and curtain. A method such as coating, lip coating, or extrusion coating using a die coater or the like.

The heating and drying temperature is preferably from about 30 ° C to about 200 ° C, more preferably from 40 ° C to 180 ° C, and more preferably from 80 ° C to 160 ° C. By setting the heating temperature to the above range, an adhesive having excellent adhesive properties can be obtained. The drying time can be suitably and suitably used. The drying time is preferably about 5 seconds to 20 minutes, preferably 30 seconds to 10 minutes, and more preferably 1 minute to 8 minutes.

When the base adhesive composition is an active energy ray-curable adhesive, the light-diffusing adhesive layer can be formed by irradiating an active energy ray such as ultraviolet rays. High-pressure mercury lamps, low-pressure mercury lamps, metal halide lamps, chemical lamps, and the like can be used for the ultraviolet irradiation.

The aforementioned support may use, for example, a release-treated sheet. As the release-treated sheet, a polyoxynitride release liner is preferably used.

An adhesive sheet having an adhesive layer formed on the release-treated sheet, and in the case where the adhesive layer is exposed, the adhesive layer may be protected by a release-treated sheet (separation member) before being used for practical use. . In actual use, the aforementioned peeled sheet is peeled off.

The constituent material of the separator is, for example, a porous material such as a plastic film, paper, cloth, or nonwoven fabric, or a suitable sheet such as a mesh, a foamed sheet, a metal foil, or the like, but excellent in surface smoothness. From this point of view, it is preferred to use a plastic film.

The plastic film may, for example, be a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, or polyethylene terephthalate. An ester film, a polybutylene terephthalate film, a polyurethane film, an ethylene-vinyl acetate copolymer film, or the like.

The thickness of the separator is generally 5 to 200 μm, preferably about 5 to 100 μm. In the separator, it is also possible to use a release agent such as an oxygen-based, fluorine-based, long-chain alkyl or fatty acid amide-based release agent, a vermiculite powder, or the like for release and antifouling treatment, or a coating type or kneading. Antistatic treatment such as type and evaporation. In particular, by appropriately applying a release treatment such as an oxygen treatment, a long-chain alkyl treatment, or a fluorine treatment to the surface of the separator, the peeling property from the pressure-sensitive adhesive layer can be further improved.

The haze value of the formed light-diffusing adhesive layer is preferably 10 to 99%, preferably 10 to 96%, more preferably 20 to 96%, and particularly preferably 40 to 80%. By setting the haze value within the above range, it is preferable to obtain the desired diffusion performance and to suppress the occurrence of waviness and glare. The light diffusing property of the light diffusing adhesive can be controlled by adjusting the constituent material of the matrix (adhesive), the constituent materials of the light diffusing fine particles, the volume average particle diameter, the blending amount, and the like.

The total light transmittance of the light-diffusing adhesive layer is preferably 75% or more, more preferably 80% or more, and still more preferably 85% or more.

(2) Transparent adhesive layer The adhesive layer for optical members of the present invention may contain a transparent adhesive layer other than the light-diffusing adhesive layer as described above.

The transparent adhesive layer is not particularly limited, and may be formed of an adhesive composition containing a base polymer and a crosslinking agent. The adhesive composition can be used as an acrylic, synthetic rubber, gum or polyoxygen adhesive, etc., but it is preferably polymerized by (meth)acrylic acid from the viewpoints of transparency, heat resistance and the like. An acrylic adhesive as a base polymer.

The monomer component contained in the (meth)acrylic polymer can be preferably used as exemplified in the above-mentioned base adhesive composition, and is preferably an alkyl (meth)acrylate (a1) or a hydroxyl group-containing monomer ( A3) and the nitrogen-containing monomer (a4) are (meth)acrylic polymers as a monomer component. Further, the monomer component contained in the (meth)acrylic polymer preferably does not contain a carboxyl group-containing monomer. The blending ratio of each monomer and the method of forming the transparent adhesive layer can be exemplified by the same method as in the case of the light-diffusing adhesive layer.

The haze of the transparent adhesive layer is not particularly limited, but is preferably 0.01 to 5%, more preferably 0.05 to 5%, still more preferably 0.1 to 3%. By setting the haze of the transparent adhesive layer to the above range, optical design such as haze is easy, and therefore it is preferable.

In addition, the thickness of the transparent adhesive layer is not particularly limited, and when the pressure-sensitive adhesive layer is bonded to the light-diffusing adhesive layer, the thickness of the adhesive layer is 20 μm or more, and is not particularly limited, but preferably 20 to 300 μm. ~300 μm is preferred. By setting the thickness of the transparent adhesive layer to the above range, it is preferable to bond the fine unevenness of the material to be bonded or the uneven portion providing the optical function.

(3) Adhesive layer for optical member The adhesive layer for optical members of the present invention may be formed of only one layer of the light-diffusing adhesive layer as described above, or may have at least one layer of the light-diffusing adhesive layer and at least one layer. A layer of transparent adhesive is formed.

The adhesive layer for an optical member of the present invention is suitable for application to an optical member, and the optical member will be described later. Among the optical members, a brightness enhancing film and a polarizing film can also be suitably used.

The adhesive layer of the optical member of the present invention has a haze value of 10 to 96% as a whole, preferably 20 to 96%, more preferably 30 to 96%. When the haze value is less than 10%, there is an unbalanced state of light from the backlight and the cymbal, and since it is impossible to eliminate the unevenness of light, display unevenness may occur. Moreover, when the haze value of the adhesive layer exceeds 96%, a large amount of particles need to be added to the adhesive layer, and at this time, the stress relaxation property and the adhesion property of the adhesive layer are lowered and the durability is poor.

2. Optical member with an adhesive layer The optical member with an adhesive layer of the present invention is characterized in that it has at least one layer of the above-mentioned adhesive member for an optical member on at least one surface of the optical member.

The material used in the production of various image display devices and the like can be used as the optical member, and the type thereof is not particularly limited, and examples thereof include a polarizing film, a phase difference plate, a brightness enhancement film, and an anti-glare sheet. Further, the optical member may be a laminate of a polarizing film and a phase difference plate or a laminate of a phase difference plate, a laminate of a polarizing film, a brightness enhancement film or an anti-glare sheet, and the like, and the optical material may be laminated in two or more layers. Things. Among them, a brightness enhancement film and a polarizing film are preferred.

Generally, a polarizing film having a transparent protective film on one side or both sides of a polarizing member can be used.

The polarizer is not particularly limited, and various polarizers can be used. The polarizing material may be a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film or an ethylene-vinyl acetate copolymer-based partially saponified film, which adsorbs iodine or a dichroic dye. The coloring material is uniaxially stretched, and a polyene-based alignment film such as a dehydrated material of polyvinyl alcohol or a dehydrochlorinated product of polyvinyl chloride is used. Among them, a polarizing member composed of a polyvinyl alcohol-based film and a dichroic substance such as iodine is particularly preferable. The thickness of the polarizers is not particularly limited, but is generally about 5 to 80 μm.

A polarizing member obtained by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretching can be produced, for example, by immersing polyvinyl alcohol in an aqueous solution of iodine to dye and extending it to 3 to 7 times the original length. . It may also be immersed in an aqueous solution containing potassium bromide such as boric acid or zinc sulfate or zinc chloride as needed. Further, it is also possible to immerse the polyvinyl alcohol-based film in water for washing with water before dyeing. By washing the polyvinyl alcohol-based film with water, the dirt and the anti-caking agent on the surface of the polyvinyl alcohol-based film can be washed, and the polyvinyl alcohol-based film can be swollen to prevent unevenness such as uneven dyeing. The extension may be carried out after dyeing with iodine, or may be dyed while stretching, or may be dyed with iodine after stretching. It can also be extended in an aqueous solution of boric acid, potassium bromide or the like or in a water bath.

Further, in the present invention, a thin polarizer having a thickness of 10 μm or less can also be used. From the viewpoint of thinning, it is preferred that the thickness be 1 to 7 μm. Such a thin polarizer is preferred because it has less thickness unevenness and is excellent in visibility, and has small dimensional change, so that durability is excellent, and the thickness of the polarizing plate is also thinner.

As a thin type of polarizing member, for example, Japanese Patent Laid-Open No. 51-069644, Japanese Patent Laid-Open Publication No. 2000-338329, International Publication No. 2010/100917, and PCT/JP2010/001460 The specification is a thin polarizing film described in the specification of Japanese Patent Application No. 2010-269002 and the specification of No. 2010-263692. The thin polarizing film can be obtained by a method comprising a step of stretching a layer of a polyvinyl alcohol-based resin (hereinafter also referred to as a PVA-based resin) and a resin substrate for stretching in a layered body, and a dyeing step. . According to this production method, even if the PVA-based resin layer is thinned, it can be supported by the resin substrate for stretching and can be stretched without causing breakage due to stretching.

As the thin polarizing film, in the method including the step of stretching in the state of the laminated body and the dyeing step, the high-magnification extension and the polarizing performance can be improved, and it is preferable to use the specification of International Publication No. 2010/100917, PCT. / JP 2010/001460, or Japanese Patent Application No. 2010-269002, Japanese Patent Application No. 2010-263692, the disclosure of which is incorporated herein by reference. The method described in the specification of the patent application No. 2010-269002, and the specification of the Japanese Patent Application No. 2010-263692, which is included in the method of performing the auxiliary air extension step before extending in the aqueous boric acid solution.

The transparent protective film provided on one side or both sides of the polarizing member is preferably a material which is excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropic property and the like. Examples thereof include polyester polymers such as polyethylene terephthalate and polyethylene naphthalate; cellulose polymers such as diethyl phthalocyanine and triethylene fluorene; and polymethyl methacrylate An acrylic polymer such as an ester; a styrene polymer such as polystyrene or an acrylonitrile-styrene copolymer (AS resin); and a polycarbonate polymer. Further, examples of the polymer which forms the transparent protective film include polyethylene, polypropylene, polyolefin having a cyclic system or a norbornene structure, and polyolefin polymerization such as an ethylene-propylene copolymer. a phthalamide polymer such as a vinyl chloride polymer, a nylon or an aromatic polyamine, an imine polymer, a fluorene polymer, a polyether fluorene polymer, a polyether ether ketone polymer, or a poly a thiobenzene-based polymer, a vinyl alcohol polymer, a vinylidene chloride polymer, an ethylene butyral polymer, an aryl ester polymer, a polyoxymethylene polymer, an epoxy polymer or the aforementioned polymer Blends and the like. The transparent protective film can also be formed into a hardened layer of a thermosetting resin such as an acrylic, urethane, acrylamide, or epoxy, or a cured layer of an ultraviolet curable resin. .

The thickness of the transparent protective film can be appropriately determined, and it is generally about 1 to 500 μm from the viewpoints of workability and thinness such as strength and workability.

The polarizer and the protective film are usually adhered to each other by a water-based adhesive or the like. The water-based adhesive may, for example, be an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, a vinyl-based latex, an aqueous polyurethane or an aqueous polyester. In addition to the above, examples of the adhesive for the polarizer and the transparent protective film include an ultraviolet curable adhesive, an electron beam curable adhesive, and the like. The electron beam-curable polarizing film exhibits an appropriate adhesion to the above various transparent protective films with an adhesive. Further, the adhesive used in the present invention may contain a metal compound filler.

A surface of the transparent protective film that is not attached to the polarizer may be provided with a hard layer or treated with anti-reflection treatment and anti-sticking, diffusion, or anti-glare treatment.

An example of a specific use form of the optical member with an adhesive layer of the present invention is shown in Fig. 2 . The polarizing film 10 (optical member with an adhesive layer) having the adhesive layer 1 for optical members of the present invention can be used by bonding the adhesive layer to the level difference surface of the cymbal sheet 20. Since the optical member with the adhesive layer of the present invention has the adhesive layer for an optical member of the present invention, it can be bonded without voids in accordance with the above-described height difference. In FIG. 2, the polarizing film 10 is a member having the protective film 12 on both surfaces of the polarizing member 11, but may be a one-side protective polarizing film having the protective film 12 on one side of the polarizing member 11. Further, the cymbal sheet 20 typically has a substrate 22 and a crotch portion 21.

Since the adhesive layer 1 for an optical member of the present invention is provided with a light diffusing function, it can be used instead of the diffusing sheet which is usually provided on the backlight side of the image display device.

3. Image Visual Display Device The image display device of the present invention is characterized by comprising the optical member with the above-mentioned adhesive layer. The image display device of the present invention may be an optical member containing the adhesive layer of the present invention, and other structures may be the same as those of the conventional image display device.

The image display device of the present invention has high reliability because it includes the optical member with the above-mentioned adhesive layer. Moreover, since the adhesive layer for optical members of the present invention is provided with a light diffusing function, the optical member with the adhesive layer can be used instead of the diffusing sheet provided on the backlight side, and the image display device can be made thin. Example

The invention is specifically illustrated by the following examples, but the invention is not limited by the examples. In addition, parts and % in each case are based on weight. The evaluation items of the examples and the like were measured as follows.

Production Example 1 (Production of Light-Diffusion Adhesive Composition (A-1)) In a separable flask equipped with a thermometer, a stirrer, a reflux cooling tube, and a nitrogen introduction tube, 2-ethyl as a monomer component was blended. 70 parts of hexyl acrylate (2EHA), 15 parts of N-vinyl-2-pyrrolidone (NVP) and 15 parts of 2-hydroxyethyl acrylate (HEA), photopolymerization initiator (trade name: IRGACURE 184, BASF Corporation After 0.1 part, the ultraviolet ray was irradiated until the viscosity (measurement condition: BH viscometer No. rotor, 10 rpm, measurement temperature: 30 ° C) became about 20 Pa·s, and a part of the polymerized prepolymer obtained as the above monomer component was obtained. Composition.

Next, 0.2 part of an isocyanate crosslinking agent was blended with respect to 100 parts of the obtained prepolymer composition (trade name: CORONATE L, toluene diisocyanate adduct of trimethylolpropane, manufactured by Japan Polyurethane Industry Co., Ltd.) A base adhesive composition (A-1) was obtained. The resulting base adhesive composition (A-1) had a refractive index of 1.475.

14 parts of polyoxynoxy resin fine particles as light diffusing fine particles were added to 100 parts of the obtained base adhesive composition (A-1) (trade name: Tospearl 145, volume average particle diameter: 4 μm, refractive index: 1.43) , a polysiloxane resin-based fine particle, manufactured by Momentive Advanced Materials Co., Ltd., to obtain a light-diffusing adhesive composition (A-1).

Production Example 2 to 5 (Production of Light-Diffusion Adhesive Compositions (A-2) to (A-5)) The production amount of the light-diffusing fine particles was changed as shown in Table 1 in Production Example 1, and the production example was also used. The light-diffusing adhesive composition (A-2) to (A-5) was produced in the same manner.

Production Example 6 (Production of Light-Diffusion Adhesive Composition (A-6)) In a 4-necked flask equipped with a stirring separator, a thermometer, a nitrogen introduction tube, and a cooler, 100 parts of butyl acrylate and 5 parts of acrylic acid were used. 1 part of hydroxyethyl acrylate and 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator were placed together with 100 parts of ethyl acetate (monomer concentration: 50%), and nitrogen was introduced while stirring slowly. After nitrogen substitution, the liquid temperature in the flask was maintained at around 55 ° C for 8 hours, and a solution of an acrylic polymer (A-6) having a weight average molecular weight (Mw) of 1.8 million was prepared.

An isocyanate crosslinking agent (trade name: CORONATE L, trimethylolpropane/toluene diisocyanate 3-polymer adduct, is added to 100 parts of the solid content of the acrylic polymer (A-6) solution obtained above. Japan Polyurethane Industry Co., Ltd.) 0.66 parts, benzylidene peroxide (NYPER BMT, manufactured by Nippon Oil & Fats Co., Ltd.) 0.3 parts, decane coupling agent (trade name: KBM403, Shin-Etsu Chemical Co., Ltd.) 0.2 A base adhesive composition (A-6) was obtained.

The polyoxynoxy resin fine particles as light diffusing fine particles were blended with respect to 100 parts of the solid content of the obtained base adhesive composition (A-6) (trade name: Tospearl 145, volume average particle diameter: 4 μm, refractive index: 1.43) 26 parts of polysiloxane resin fine particles, manufactured by Momentive Advanced Materials Co., Ltd., and a light diffusing adhesive composition (A-6) was prepared.

Production Example 7 (Production of Light-Diffusing Adhesive Composition (A-7)) The production amount of the light-diffusing fine particles was changed as shown in Table 1 in Production Example 6, and the light diffusion adhesive was produced in the same manner as in Production Example 6. Composition (A-7).

Production Example 8 to 12 (Production of Light-Diffusion Adhesive Compositions (A-8) to (A-12)) The production amount of the light-diffusing fine particles was changed as shown in Table 1 in Production Example 1, and The light-diffusing adhesive composition (A-8) to (A-12) was produced in the same manner as in Example 1.

【Table 1】

Example 1 (Production of Light-Diffusion Adhesive Layer) On a release-treated surface of a polyester film (trade name: Diafoil MRF, manufactured by Mitsubishi Resin Co., Ltd.) having a thickness of 38 μm which was subjected to polyfluorination treatment on one side, coating was carried out. The light-diffusing adhesive composition (A-1) obtained in Production Example 1 was formed so that the thickness of the obtained light-diffusing adhesive layer was 23 μm to form a coating layer. Next, a polyester film (trade name: Diafoil MRE, manufactured by Mitsubishi Resin Co., Ltd.) having a thickness of 38 μm which was subjected to polysilicon stripping treatment on one surface was coated on the surface of the formed coating layer to peel off the surface of the film. Become the coating layer side. Thereby, the coating layer of the light-diffusing adhesive composition blocks oxygen. The coated sheet obtained by the use of a chemical lamp (manufactured by Toshiba Corporation) was irradiated with ultraviolet rays having an illuminance of 100 mW/cm ² (measured with Topcon UVR-T1 having a maximum sensitivity of about 350 nm) for 30 seconds. The coating layer is hardened to form a light-diffusing adhesive layer, and an adhesive sheet is produced. The polyester film which is coated on both sides of the adhesive layer functions as a release liner.

Examples 2 to 12 and Comparative Examples 1 to 3, 6, and 7 The thickness of the light-diffusing adhesive composition used after drying was changed to those shown in Table 2, and an adhesive sheet was produced in the same manner as in Example 1.

Example 13 (Production of the first layer and the third layer (transparent adhesive layer)) The light-diffusing adhesive composition (A-8) obtained in Production Example 8 was used to have a thickness of the adhesive layer of 50 μm. Further, an adhesive sheet for a transparent adhesive layer was produced in the same manner as in Example 1. Make 2 pieces of the same thing.

(Production of the second layer (light-diffusing adhesive layer)) On the peeling-treated surface of a polyester film (trade name: Diafoil MRF, manufactured by Mitsubishi Resin Co., Ltd.) having a thickness of 38 μm which was subjected to polyfluorination treatment on one side, The light-diffusing adhesive composition (A-7) obtained in Production Example 7 was applied so that the thickness of the obtained light-diffusing adhesive layer was 23 μm to form a coating layer, and the film was dried at 155 ° C for 1 minute to form a light-diffusing adhesive layer.

The transparent adhesive layer obtained as described above was peeled off from the release sheet on the side of the adhesive sheet, and the transparent adhesive layer was bonded to both surfaces of the obtained light-diffusing adhesive layer to form an adhesive layer for an optical member.

Example 14 The thickness of the light-diffusing adhesive composition used after drying was changed to those shown in Table 2, and an adhesive sheet was produced in the same manner as in Example 13.

Example 15 (Production of the second layer (light-diffusing adhesive layer)) A polyester film (trade name: Diafoil MRF, manufactured by Mitsubishi Resin Co., Ltd.) having a thickness of 38 μm which was subjected to polyfluorination treatment on one side. On the surface, the light-diffusing adhesive composition (A-10) obtained in Production Example 10 was applied so that the thickness of the obtained light-diffusing adhesive layer was 23 μm to form a coating layer. Next, a polyester film (trade name: Diafoil MRE, manufactured by Mitsubishi Resin Co., Ltd.) having a thickness of 38 μm which was subjected to polysilicon stripping treatment on one surface was coated on the surface of the formed coating layer to peel off the surface of the film. Become the coating layer side. Thereby, the coating layer of the light-diffusing adhesive composition blocks oxygen. The coated sheet obtained by the use of a chemical lamp (manufactured by Toshiba Corporation) was irradiated with ultraviolet rays having an illuminance of 100 mW/cm ² (measured with Topcon UVR-T1 having a maximum sensitivity of about 350 nm) for 30 seconds. The coating layer is hardened to form a light-diffusing adhesive layer, and an adhesive sheet is produced. The polyester film which is coated on both sides of the adhesive layer functions as a release liner.

The adhesive layer was used as the second layer (light-diffusing adhesive layer) in Example 13, and an adhesive sheet was produced in the same manner as in Example 13.

In the diffusion adhesive compositions used in Examples 16 and 17, and Comparative Examples 4 to 5, an adhesive sheet was produced in the same manner as in Example 15 except that the thickness was changed as shown in Table 2.

The following evaluations were performed on the adhesive layers obtained in the examples and the comparative examples. The evaluation results are shown in Table 2.

<Refractive Index of Substrate Adhesive Composition> The measurement was carried out by using an Abbe refractometer (trade name: DR-M2, manufactured by ATAG).

<Haze value> The haze value of each of the light-diffusing adhesive layer and the transparent adhesive layer used in the examples and the comparative examples, and the total haze value of the adhesive layer obtained in the examples and the comparative examples were measured by JIS 7136. The method was measured using a haze meter (trade name: HN-150, manufactured by Murakami Color Research Institute).

<Laminating> A polarizing film having a brightness-enhancing film (trade name: DBEF-Q, manufactured by 3M) was attached to a polarizing film (trade name: CVT, manufactured by Nitto Denko Co., Ltd.). The release film on the side of the adhesive sheet obtained in the examples and the comparative examples was peeled off and bonded to the brightening film side of the polarizing film. Further, the release film on the other side of the adhesive sheet was peeled off, and the sheet having the unevenness of 50 μm or 5 μm was applied to the wafer by a hand-held roller, and autoclaved at 50 ° C and 5 atm for 15 minutes. The state after the bonding was visually confirmed, and the evaluation was performed based on the following evaluation criteria. ◎: Even when a ruthenium sheet having 50 μm unevenness was used, it was possible to perform bonding without generating bubbles of 200 μm or more. ○: When a ruthenium sheet having 50 μm unevenness is used, bubbles of 200 μm or more are generated. However, when a ruthenium sheet having 5 μm unevenness is used, it can be bonded without generation of bubbles of 200 μm or more. X: When a ruthenium sheet having 5 μm unevenness was used, it was not possible to bond it without generation of bubbles of 200 μm or more.

<Display unevenness> The polarizing film obtained by bonding the polarizing film obtained in the examples and the comparative examples was cut into a size of 400 mm in length × 250 mm in width to prepare a sample. The sample was bonded to an alkali-free glass plate having a thickness of 0.07 mm by a laminator, and the polarizing plate of the transparent adhesive layer was bonded to the opposite surface to be orthogonally polarized, and then carried out at 50 ° C and 5 atm. An evaluation sample was prepared by autoclaving for 15 minutes. Then, the light leakage was visually observed on a backlight of 10,000 candelas, and the corner unevenness was evaluated according to the following criteria. ◎: There is no uneven phenomenon, and there is no problem in practical use. ○: Unevenness occurs but only a small amount appears in the display area, and there is no problem in practical use. ×: An uneven phenomenon occurs and appears prominently in the display area, and there is a problem in practical use.

<Durability> Adhesive layer obtained by bonding glass/polarized film (trade name: CVT, manufactured by Nitto Denko Co., Ltd.)/brightening film (trade name: DBEF-Q, manufactured by 3M)/Examples and Comparative Examples/ In the state of the ruthenium, the state after being placed in an environment of 80 ° C and 60 ° C / 90% RH for 240 hours was visually observed. Evaluation was performed according to the following evaluation criteria. 〇: No blistering or peeling of more than 100 μm occurred. ×: Foaming and peeling exceeding 100 μm occurred.

<Processability> The adhesive layer obtained in the examples and the comparative examples with the separator was punched with a punching knife having a size of 10 cm × 20 cm. The state at the time of press was visually confirmed, and it evaluated based on the following evaluation criteria. ○: Stamping can be performed without any problem. ×: The sample was attached to the knife and could not be punched.

【Table 2】

1‧‧‧Adhesive layer for optical components
2‧‧‧Light diffusing adhesive layer
3‧‧‧Transparent adhesive layer
4‧‧‧Separate parts
10‧‧‧Polarized film
11‧‧‧ polarizer
12‧‧‧Protective film
20‧‧‧ Picture
21‧‧‧稜鏡
22‧‧‧Substrate

1(a) to 1(d) are cross-sectional views schematically showing an embodiment of an adhesive layer for an optical member of the present invention. Fig. 2 is a cross-sectional view schematically showing a use form of an adhesive layer for an optical member of the present invention.

1‧‧‧Adhesive layer for optical components

2‧‧‧Light diffusing adhesive layer

3‧‧‧Transparent adhesive layer

4‧‧‧Separate parts

Claims (12)

An adhesive layer for an optical member, comprising at least one light-diffusing adhesive layer having a thickness of 5 to 300 μm, wherein the light-diffusing adhesive layer is composed of a base adhesive composition containing a (meth)acrylic polymer and light The diffusing fine particles are formed, and the thickness of the entire adhesive layer is 20 μm or more and the haze is 10 to 96%. The adhesive member layer for an optical member according to claim 1, wherein the light diffusing fine particles are polyoxynoxy resin fine particles. The adhesive member layer for an optical member according to claim 1, wherein the light diffusing fine particles have a refractive index lower than that of the base adhesive composition. An adhesive layer for an optical member according to claim 1, wherein the light-diffusing fine particles have a volume average particle diameter of 1 to 5 μm. An adhesive layer for an optical member according to claim 1, wherein at least one side of the light-diffusing adhesive layer has a transparent adhesive layer having a haze of 0.01 to 5%. The adhesive layer for an optical member according to claim 5, wherein the thickness of the light-diffusing adhesive layer is 5 to 30 μm, and the thickness of the transparent adhesive layer having a haze of 0.01 to 5% is 50 to 300 μm. The adhesive layer for an optical member according to claim 1, wherein the content of the light diffusing fine particles in the light diffusing adhesive layer is 3 to 30% by weight. The adhesive layer for an optical member according to any one of claims 1 to 7, wherein the (meth)acrylic polymer contains an alkyl (meth)acrylate and a carboxyl group-containing monomer as a monomer component. The adhesive member layer for an optical member according to claim 5, wherein the transparent adhesive layer contains a (meth)acrylic polymer containing an alkyl (meth)acrylate and a hydroxyl group-containing monomer. And a nitrogen-containing monomer as a monomer component. The adhesive member layer for an optical member according to claim 9, wherein the (meth)acrylic polymer contained in the transparent adhesive layer does not contain a carboxyl group-containing monomer as a monomer component. An optical member with an adhesive layer, characterized in that at least one side of the optical member has at least one layer of the adhesive member for an optical member according to any one of claims 1 to 10. An image display apparatus characterized by comprising an optical member such as the adhesive layer of claim 11.