TWI428415B - An adhesive composition for an optical film, an adhesive type optical film, and an image display device - Google Patents

Description

Adhesive composition for optical film, adhesive optical film and image display device

The present invention relates to an adhesive composition for an optical film which requires transparency and an adhesive optical film in which an adhesive layer is formed on at least one surface of an optical film by the adhesive composition. Further, the present invention relates to an image display device such as a liquid crystal display device or an organic EL display device using the above-described adhesive optical film. As the optical film, a polarizing plate, a phase difference plate, an optical compensation film, a brightness enhancement film, and the like can be used.

In the case of a liquid crystal display or the like, it is necessary and indispensable to arrange a polarizing element on both sides of the liquid crystal cell in view of the image forming method, and a polarizing plate is usually attached. Further, in addition to the polarizing plate on the liquid crystal panel, various optical elements can be used in order to improve the display quality of the display. For example, a phase difference plate for preventing coloration, a viewing angle expansion film for improving the viewing angle of the liquid crystal display, and a brightness enhancement film for improving the contrast of the display may be used. These films are collectively referred to as optical films.

When an optical member such as the above optical film is attached to a liquid crystal cell, an adhesive is usually used. Further, in the case of the optical film, the liquid crystal cell, or the optical film, the loss of light is usually reduced, and each material is adhered with an adhesive. In the above case, there is an advantage that the drying step is not required when the optical film is fixed. Therefore, an adhesive optical film in which an adhesive is applied to one side of the optical film as an adhesive layer is usually used.

The required characteristics required for the above-mentioned adhesive are such that when the optical film is bonded to the liquid crystal cell, the optical film can be peeled off from the liquid crystal panel even when the bonding position is wrong or the foreign matter is caught in the bonding surface. The film is reused for the liquid crystal cell. In the peeling step, it is required to easily peel off the removability (secondary workability) of the optical film from the liquid crystal panel without leaving the adhesive. In particular, in recent years, in addition to the previous panel fabrication steps, the use of a thin liquid crystal panel using a chemically etched glass has increased, and the secondary processability and processability of the optical film from the thin liquid crystal panel have become difficult. . Further, in the above-mentioned adhesive, it is required to form a pressure-sensitive adhesive layer on the optical film, and it is possible to carry out processing workability without causing contamination or peeling of the adhesive. Further, the above-mentioned adhesive is required to be subjected to an endurance test such as heating and humidification which is usually performed as an environmental acceleration test, and the problem caused by the adhesive does not occur.

In the prior art, a method of solving the problem of the secondary workability of the liquid crystal panel has been proposed to include a plasticizer or an oligomer component in the acrylic polymer as the base polymer of the acrylic pressure-sensitive adhesive (Patent Document 1). However, with the acrylic pressure-sensitive adhesive, the above-described thin liquid crystal panel cannot satisfy the secondary workability and the workability.

In addition to the above, as the acrylic adhesive used in the optical film, it is proposed to use a monomer having a hydroxyl group in the molecule and a carboxyl group or a mercapto group in the molecule in addition to the alkyl (meth)acrylate. A monomer having a functional group such as an amine group is used as a monomer component of an acrylic polymer (Patent Documents 2 and 3); in addition to an alkyl (meth)acrylate, a ruthenium-containing monomer or a ruthenium-containing monomer is also used. A nitrogen-containing monomer such as an amine-based monomer, and a peroxide and an isocyanate compound are used as a monomer component of the acrylic polymer (Patent Document 4). However, the acrylic adhesive described in the above-mentioned patent documents can improve durability, but cannot sufficiently satisfy secondary workability and workability.

Patent Document 1: Japanese Patent Laid-Open Publication No. 2003-320837

Patent Document 2: Japanese Patent Laid-Open Publication No. 2004-091499

Patent Document 3: Japanese Patent Laid-Open Publication No. 2004-091500

Patent Document 4: Japanese Patent Laid-Open Publication No. 2007-138147

An object of the present invention is to provide an adhesive composition for an optical film which can form an adhesive layer which can satisfy secondary workability and workability and which is less likely to cause pits or the like, wherein the secondary workability means that it does not remain. In the case of a viscose, the optical film is easily peeled off from the liquid crystal panel, and the processability means that the adhesive layer can be formed on the optical film without being contaminated or peeled off by the adhesive.

Moreover, an object of the present invention is to provide an adhesive optical film having an adhesive layer formed of the above-described adhesive composition for an optical film, and to provide an image display device using the above-mentioned adhesive optical film.

The inventors of the present invention have conducted intensive studies on the above problems, and as a result, have found the following adhesive composition for an optical film, and have completed the present invention.

That is, the present invention relates to an adhesive composition for an optical film, which comprises: a (meth)acrylic polymer containing (a) an alkyl (meth)acrylate in an amount of 50 to 99.79 wt%, (b) a monomer containing 0.01 to 0.45 wt% of a tertiary amino group monomer and (c) 0.1 to 3 wt% of a hydroxyl group-containing monomer, and having a weight average molecular weight of 1.5 to 3.5 million; and a crosslinking agent One of a group consisting of free hexamethylene diisocyanate, hydrogenated benzene dimethylene diisocyanate and isophorone diisocyanate or a polyisocyanate compound derived therefrom, and it is relative to 100 parts by weight of the (meth) group The acrylic polymer is 0.01 to 2 parts by weight.

In the above adhesive composition for an optical film, it is preferred that the (meth)acrylic polymer further contains (d) a carboxyl group-containing monomer in an amount of 0.1 to 3% by weight.

In the above-mentioned adhesive composition for an optical film, it is preferably contained in an amount of 0.01 to 1 part by weight based on 100 parts by weight of the (meth)acrylic polymer. Further, it is preferred that the decane coupling agent has an amine group.

The present invention also relates to an adhesive layer for an optical film obtained by applying the above-mentioned adhesive composition for an optical film to a crosslinking reaction, and the gel fraction after coating for 1 hour is 55 to 95%.

The present invention also relates to an adhesive optical film obtained by forming the above-mentioned adhesive layer for an optical film on at least one side of an optical member.

The present invention also relates to an image display apparatus using at least one of the above-described adhesive optical films.

In the adhesive composition for an optical film of the present invention, the (meth)acrylic polymer as the base polymer contains a tertiary amino group-containing monomer as a monomer unit in a small amount of 0.01 to 0.45 wt%. . By adopting such a configuration, the workability and secondary workability of the optical member obtained from the adhesive composition for an optical film can be improved, and the adhesive can be prevented from falling off or being contaminated during processing, and even from a thin liquid crystal panel, In particular, in the case where the optical film is peeled off using a liquid crystal panel having chemically etched glass, peeling can be easily performed without leaving the adhesive. Further, it is possible to peel off from the liquid crystal panel without breaking the optical film. As a result, the liquid crystal panel can be effectively reused without the damage of the thin liquid crystal panel.

In the case of the tertiary amino group-containing monomer contained in the above-mentioned small amount in the (meth)acrylic polymer, it is considered that the adhesive can be formed after the adhesive layer is formed by the crosslinking reaction using the crosslinking agent. The cross-linking stability of the layer.

Further, in the adhesive composition for an optical film of the present invention, since the (meth)acrylic polymer contains a hydroxyl group-containing monomer as a monomer unit, durability can be improved and secondary workability can be improved.

The adhesive composition of the present invention is one selected from the group consisting of hexamethylene diisocyanate, hydrogenated benzylene diisocyanate and isophorone diisocyanate in the above specified ratio or from the same. In the case where the polyisocyanate compound is used as a crosslinking agent, in particular, the quick-acting property at the time of crosslinking described above by using the tertiary amino group-containing monomer can be improved. That is, the aging step after coating may be omitted. Further, as the crosslinking agent, a decane coupling agent can be further used within the above-specified range. In particular, when a decane coupling agent is used in combination with an isocyanate compound, the crosslinking stability is improved, and secondary workability and workability can be improved. Moreover, in the manufacturing operation of the optical member having such an adhesive, it is resistant to breakage of the panel and cracking of the film even in the subsequent use.

The adhesive composition for an optical film of the present invention comprises 50 to 99.79 wt% of an alkyl (meth)acrylate, 0.01 to 0.45 wt% of a tribasic amino group-containing monomer, and 0.1 to 3 wt% of a hydroxyl group-containing monomer. A (meth)acrylic polymer is used as the base polymer. Further, in the present invention, the (meth)acrylic polymer of the base polymer may contain 0.1 to 3% by weight of any carboxyl group-containing monomer.

As the alkyl (meth)acrylate, the alkyl group of the alkyl (meth)acrylate has a carbon number of about 2 to 18. The alkyl group may be any of a straight chain and a branched chain. The average carbon number of the above alkyl group is preferably 2 to 14, and more preferably the average carbon number is 3 to 12, and more preferably the average carbon number is 4 to 9. Further, (meth) acrylate means acrylate and/or methacrylate, and has the same meaning as (meth) of the present invention.

Specific examples of the alkyl (meth)acrylate include ethyl (meth)acrylate, n-butyl (meth)acrylate, second butyl (meth)acrylate, and third alkyl (meth)acrylate. Ester, isobutyl (meth)acrylate, n-amyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, (meth)acrylic acid Isoamyl ester, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-decyl (meth)acrylate, isophthalide (meth)acrylate Ester, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, isomyristyl (meth) acrylate, trimethyl (meth) acrylate An alkyl ester, n-tetradecyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, and the like. Among them, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and the like can be exemplified, and these may be used singly or in combination.

In the present invention, the alkyl (meth)acrylate is 50 to 99.79% by weight based on the total monomer component of the (meth)acrylic polymer. It is preferably from 85 to 99.79 wt%, more preferably from 87 to 99.79% by weight, still more preferably from 90 to 99.79% by weight, still more preferably from 98 to 99.79% by weight. When the amount of the above (meth)acrylic monomer is too small, it becomes insufficient in adhesion and is not preferable.

Further, examples of the tertiary amino group-containing monomer include those having a tertiary amino group and a (meth) acrylonitrile group. As the tertiary amino group, a tertiary aminoalkyl group is preferred. Examples of the tertiary amino group-containing monomer include N,N-dialkylaminoalkyl(meth)acrylamide and N,N-dialkylaminoalkyl (meth)acrylate. Specific examples of the tertiary amino group-containing monomer include, for example, N,N-dimethylaminoethyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)propene. Indoleamine, N,N-diethylaminoethyl(meth)acrylamide, N,N-diethylaminopropyl(meth)acrylamide, (meth)acrylic acid N,N- Dimethylaminoethyl ester, N,N-dimethylaminopropyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, N,N (meth)acrylate - diethylaminopropyl ester.

Further, even if a nitrogen-containing monomer is used and is a monomer other than a tertiary amino group-containing monomer, for example, maleic imine, N-cyclohexylmaleimide, N-phenylmaleimide, or the like Maleic imine monomer; N-(methyl) propylene oxymethylene succinimide or N-(methyl) propylene fluorenyl-6-oxyhexamethylene succinimide, Amber quinone imine monomer such as N-(methyl)propenyl-8-oxy octamethyl succinimide; (meth) acrylamide, N,N-dimethyl (methyl) Acrylamide, N,N-diethyl(meth)acrylamide, N,N-diethylmethacrylamide, N-isopropyl(meth)acrylamide, N-methylol N-substituted guanamine monomer such as (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide; a monomer having a secondary amine group such as tributylaminoethyl acrylate; diacetone (meth) acrylamide, N-vinylacetamide, N, N'-methylene bis (methyl) ) acrylamide, N-vinyl caprolactam, N-propylene decylmorpholine, N-propylene hydrazinopiperidine, N-methylpropenyl piperidine, N-propenylpyrrolidine, etc., only With it also To improve secondary processing, workability.

The tertiary amino group-containing monomer is used in a proportion of 0.01 to 0.45 wt% based on the total amount of the monomer components forming the (meth)acrylic polymer. The proportion of the tertiary amino group-containing monomer is preferably from 0.01 to 0.40% by weight, more preferably from 0.01 to 0.35% by weight. When the proportion of the tertiary amino group-containing monomer is less than 0.01% by weight, the crosslinking stability of the pressure-sensitive adhesive layer is inferior, the secondary workability and the workability are not satisfied, and the durability is also unfavorable. On the other hand, from the viewpoint of secondary workability, it is not preferable if the ratio of the tertiary amino group-containing monomer is too large, and the control is 0.45 wt% or less.

As the hydroxyl group-containing monomer, a polymerizable functional group having an unsaturated double bond such as a (meth) acrylonitrile group or a vinyl group and having a hydroxyl group can be used without particular limitation. Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxy(meth)acrylate. Butyl ester, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, etc. (methyl a hydroxyalkyl acrylate, hydroxyethyl (meth) acrylamide; additionally, exemplified by (4-hydroxymethylcyclohexyl)methyl acrylate, N-hydroxymethyl (meth) acrylamide, N- Hydroxy (meth) acrylamide, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, and the like. Among them, preferred is a hydroxyalkyl (meth)acrylate. In particular, 4-hydroxybutyl acrylate is preferred.

The hydroxyl group-containing monomer is used in a ratio of 0.01 to 3% by weight based on the total amount of the monomer components forming the (meth)acrylic polymer. The proportion of the hydroxyl group-containing monomer is preferably from 0.01 to 2% by weight, more preferably from 0.01 to 0.7% by weight, further preferably from 0.05 to 0.5% by weight. In order to improve durability, it is preferred to contain 0.01% by weight or more of a hydroxyl group-containing monomer. In particular, when an isocyanate crosslinking agent is used as the crosslinking agent, it is preferred to contain 0.01% by weight or more of the hydroxyl group-containing monomer in order to secure the crosslinking point with the isocyanate group. On the other hand, when the ratio of the hydroxyl group-containing monomer exceeds 3% by weight, the bonding force becomes strong, the peeling becomes heavy, and the secondary workability cannot be satisfied, which is not preferable.

As the carboxyl group-containing monomer, a polymerizable functional group having an unsaturated double bond such as a (meth) acrylonitrile group or a vinyl group and having a carboxyl group can be used without particular limitation. Examples of the carboxyl group-containing monomer include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Among them, preferred is (meth)acrylic acid, and particularly preferred is acrylic acid.

The carboxyl group-containing monomer is preferably used in a ratio of 0.01 to 3% by weight based on the total amount of the monomer component forming the (meth)acrylic polymer when it is contained. The proportion of the carboxyl group-containing monomer is preferably from 0.01 to 2% by weight, more preferably from 0.01 to 0.7% by weight, further preferably from 0.05 to 0.5% by weight. In order to improve durability, it is preferred to contain 0.01% by weight or more of a carboxyl group-containing monomer. On the other hand, when the ratio of the carboxyl group-containing monomer exceeds 3% by weight, the bonding force becomes strong, the peeling becomes heavy, and the secondary workability cannot be satisfied, which is not preferable.

The monomer component forming the (meth)acrylic polymer may be in the range of 45% by weight or less based on the total amount of the monomers, in addition to the above monomers, within the range not impairing the object of the present invention. Use a monomer other than the above. The ratio of any monomer is more preferably 40% by weight or less. Examples of the optional monomer include an aromatic ring-containing monomer having a polymerizable functional group having an unsaturated double bond such as a (meth)acryl fluorenyl group or a vinyl group and having an aromatic ring. Specific examples of the aromatic ring-containing monomer include phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, phenol ethylene oxide modified (meth)acrylate, and (methyl). 2-naphthylethyl acrylate, 2-naphthyloxyethyl acrylate, 2-(4-methoxy-1-naphthalenyloxy)ethyl (meth)acrylate, phenoxypropyl (meth)acrylate, Phenoxydiethylene glycol (meth)acrylate, thiol acrylate, pyridine acrylate, pyrrolyl acrylate, phenyl acrylate, poly(meth) acrylate, and the like.

Examples of the monomer other than the above include an acid anhydride group-containing monomer such as maleic anhydride or itaconic anhydride; a caprolactone adduct of acrylic acid; styrenesulfonic acid or allylsulfonic acid, and 2-(methyl). a sulfonic acid group containing acrylamide, 2-methylpropanesulfonic acid, (meth)acrylamide, propanesulfonic acid, sulfopropyl (meth)acrylate, (meth)acryloxynaphthalenesulfonic acid, etc. a phosphoric acid group-containing monomer such as 2-hydroxyethyl propylene decyl phosphate; a (meth)acrylic acid alkoxyalkyl group such as methoxyethyl (meth)acrylate or ethoxyethyl (meth)acrylate; A base ester monomer or the like.

Further, a vinyl monomer such as vinyl acetate, vinyl propionate, styrene, α-methylstyrene or N-vinyl caprolactam may be used; and a ring containing a glycidyl (meth)acrylate or the like may be used. Oxy acrylate monomer; polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, methoxy ethylene glycol (meth) acrylate, methoxy polypropylene glycol (meth) acrylate a glycol-based acrylate monomer such as an ester; an acrylic acid such as tetrahydrofurfuryl (meth)acrylate, fluoro(meth)acrylate, polyoxy(oxy)(meth)acrylate, or 2-methoxyethyl acrylate Ester monomer or the like.

Further, examples of the copolymerizable monomer other than the above include a decane-based monomer containing a ruthenium atom. Examples of the decane-based monomer include 3-propenyloxypropyltriethoxydecane, vinyltrimethoxydecane, vinyltriethoxydecane, 4-vinylbutyltrimethoxydecane, and 4 - vinyl butyl triethoxy decane, 8-vinyl octyl trimethoxy decane, 8-vinyl octyl triethoxy decane, 10-methyl propylene decyl decyl trimethoxy decane, 10 - propylene decyl decyl trimethoxy decane, 10-methyl propylene decyl decyl triethoxy decane, 10-propylene decyl decyl triethoxy decane, and the like.

The (meth)acrylic polymer of the present invention usually has a weight average molecular weight of from 1.5 million to 3.5 million. When durability, particularly heat resistance, is considered, it is preferred to use a weight average molecular weight of 1.5 million to 3,000,000. Further preferably, it is 1.7 million to 2.5 million, and more preferably 1.8 million to 2.5 million. If the weight average molecular weight is less than 1.5 million, it is not preferable in terms of heat resistance. Further, when the weight average molecular weight is more than 3.5 million, the adhesion and the adhesion are not preferable. In addition, the weight average molecular weight is a value calculated by GPC (gel permeation chromatography) and calculated by polystyrene conversion.

A known production method such as solution polymerization, bulk polymerization, emulsion polymerization, or various radical polymerization can be suitably selected for the production of such a (meth)acrylic polymer. Further, the obtained (meth)acrylic polymer may be any of a random copolymer, a block copolymer, a graft copolymer and the like.

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

The polymerization initiator, the chain transfer agent, the emulsifier, and the like used in the radical polymerization are not particularly limited, and can be appropriately selected and used. Further, the weight average molecular weight of the (meth)acrylic polymer can be controlled by the amount of the polymerization initiator and the chain transfer agent used, and the reaction conditions, and the appropriate amount can be adjusted depending on the type of the polymer.

Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-amidinopropane) dihydrochloride, and 2,2'-azobis [ 2-(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-azobis(2-methylpropionamidine) disulfate, 2,2'-couple Nitrogen di(N,N'-dimethylene isobutyl fluorene), 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine hydrate (Wako Pure Chemicals) Manufactured by the company, VA-057) and other azo-based initiators, persulfate such as potassium persulfate or ammonium persulfate, di(2-ethylhexyl) peroxydicarbonate and di-dicarbonate (4- Tributylcyclohexyl) ester, dibutyl butyl dicarbonate, tert-butyl peroxy neodecanoate, third hexyl peroxypivalate, tert-butyl peroxypivalate, Oxidized dilaurin, di-n-octyl peroxide, peroxy-2-ethylhexanoate (1,1,3,3-tetramethylbutyl) ester, bis(4-methylbenzhydryl) peroxide , peroxides such as benzamidine peroxide, tert-butyl peroxyisobutyrate, 1,1-di(trihexylperoxy)cyclohexane, tert-butyl hydroperoxide, hydrogen peroxide, etc. Starting agent, persulfate and sulfurous acid A combination of sodium hydrogen, a combination of a peroxide and sodium ascorbate, and the like, and a redox initiator of a peroxide and a reducing agent are combined, but are not limited thereto.

The above polymerization initiators may be used singly or in combination of two or more kinds, and the content as a whole is preferably from 0.005 to 1 part by weight, more preferably from 0.02 to 0.5 part by weight, per 100 parts by weight of the monomer.

Further, when the (meth)acrylic polymer having the above weight average molecular weight is produced by using, for example, 2,2'-azobisisobutyronitrile as a polymerization initiator, the amount of the polymerization initiator used is relative to the monomer. The total amount of the components is 100 parts by weight, preferably about 0.06 to 0.2 parts by weight, more preferably about 0.08 to 0.175 parts by weight.

Examples of the chain transfer agent include dodecyl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, mercaptoacetic acid, 2-ethylhexyl thioglycolate, and 2,3-dimercapto-1-propene. Alcohol, etc. The chain transfer agent may be used singly or in combination of two or more kinds, and the content as a whole is about 0.1 part by weight or less based on 100 parts by weight of the total of the monomer components.

Further, examples of the emulsifier used in the case of emulsion polymerization include sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, polyoxyethylene alkyl ether sulfate, and polyoxyethylene alkyl. Anionic emulsifier such as sodium phenyl ether sulfate, nonionic emulsification such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, or polyoxyethylene-polyoxypropylene block polymer Agents, etc. These emulsifiers may be used singly or in combination of two or more.

Further, as the reactive emulsifier, as an emulsifier to which a radical polymerizable functional group such as an acryl group or an allyl ether group is introduced, 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.), ADEKA REASOAP SE10N (manufactured by Asahi Chemical Co., Ltd.), etc. Since the reactive emulsifier is carried into the polymer chain after the polymerization, the water resistance is preferably improved. The amount of the emulsifier used is preferably from 0.3 to 5 parts by weight, based on 100 parts by total of the total of the monomer components, and more preferably from 0.5 to 1 part by weight, from the viewpoint of polymerization stability or mechanical stability.

Further, the adhesive composition of the present invention contains a polyisocyanate compound as a crosslinking agent. The polyisocyanate compound is selected from the group consisting of hexamethylene diisocyanate, hydrogenated dimethylene diisocyanate, and isophorone diisocyanate, or a polyisocyanate compound derived therefrom. Wherein, one or a polyisocyanate compound selected from the group consisting of hexamethylene diisocyanate, hydrogenated benzene dimethylene diisocyanate and isophorone diisocyanate comprises: hexamethylene diisocyanate, hydrogenated benzene Dimethylene diisocyanate, isophorone diisocyanate, polyol modified hexamethylene diisocyanate, polyol modified hydrogenated benzene dimethylene diisocyanate, trimer hydrogenated benzene dimethylene diisocyanate Polyol-modified isophorone diisocyanate or the like. The reaction of the exemplified polyisocyanate compound with a hydroxyl group is particularly rapidly carried out by using an acid or a base contained in the polymer as a catalyst, and therefore it is particularly preferable to facilitate the rapid crosslinking.

The above-mentioned isocyanate-based crosslinking agent may be used singly or in combination of two or more kinds. The content of the above-mentioned (meth)acrylic polymer is preferably 0.01 to 2 parts by weight based on 100 parts by weight of the above (meth)acrylic polymer. The above polyisocyanate compound crosslinking agent is more preferably contained in an amount of from 0.04 to 1.5 parts by weight, still more preferably from 0.05 to 1 part by weight. When it is less than 0.01 part by weight, there is a case where the cohesive force is insufficient and it is not preferable. On the other hand, when it exceeds 2 parts by weight, peeling is likely to occur in the durability test, which is not preferable.

Further, in order to improve the adhesion and durability, a decane coupling agent can be used in the adhesive composition of the present invention. As the decane coupling agent, a known one can be suitably used without particular limitation.

Specific examples thereof include 3-glycidoxypropyltrimethoxydecane, 3-glycidoxypropyltriethoxydecane, and 3-glycidoxypropylmethyldiethoxydecane. Epoxy-containing decane coupling agent such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxydecane; 3-aminopropyltrimethoxydecane, N-2-(aminoethyl)-3- Aminopropylmethyldimethoxydecane, 3-triethoxydecyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-γ-aminopropyltrimethoxydecane, etc. An amino group-containing decane coupling agent; 3-propenyloxypropyltrimethoxydecane, 3-methylpropenyloxypropyltriethoxydecane, etc. containing (meth)acrylonitrile decane coupling agent; Isocyanate-based decane coupling agent, etc., such as isocyanate propyl triethoxy decane. Among them, in order to establish a relationship with the durability and secondary workability at the time of humidification, it is particularly preferable to use an amine-containing decane coupling agent, but it is not limited thereto, and even other decane coupling agents are used for durability. Improvement is better.

The above decane coupling agent may be used singly or in combination of two or more kinds, and the content of the above (meth)acrylic polymer is preferably 0.01 to 2 parts by weight based on 100 parts by weight of the above (meth)acrylic polymer. The coupling agent is more preferably contained in an amount of from 0.02 to 0.6 parts by weight, still more preferably from 0.05 to 0.3 parts by weight. This improves the durability and appropriately maintains the amount of adhesion to an optical member such as a liquid crystal cell.

Further, in the present invention, a peroxide may be optionally contained as another crosslinking agent.

The peroxide of the present invention can be suitably used in consideration of operability or stability if it is a radical active species which can be generated by heating or light irradiation to crosslink the base polymer of the adhesive composition. Preferably, it is preferred to use a peroxide having a one-minute half-life temperature of from 80 ° C to 160 ° C, more preferably a peroxide of from 90 ° C to 140 ° C.

As the peroxide which can be used, for example, di(2-ethylhexyl)peroxydicarbonate (1 minute half-life temperature: 90.6 ° C) and di(4-t-butylcyclohexyl)peroxydicarbonate are mentioned. (1 minute half-life temperature: 92.1 ° C), dibutyl phthalate dihydrate (1 minute half-life temperature: 92.4 ° C), peroxy neodecanoic acid tert-butyl ester (1 minute half-life temperature: 103.5 ° C), peroxidation Tert-butyl pivalate (1 minute half-life temperature: 109.1 ° C), third butyl peroxypivalate (1 minute half-life temperature: 110.3 ° C), dilaurin peroxide (1 minute half-life temperature: 116.4 ° C) , di-n-octyl peroxide (1 minute half-life temperature: 117.4 ° C), peroxy-2-ethylhexanoic acid (1,1,3,3-tetramethylbutyl) ester (1 minute half-life temperature: 124.3 ° C ), bis(4-methylbenzhydrazide) peroxide (1 minute half-life temperature: 128.2 ° C), benzoic acid peroxide (1 minute half-life temperature: 130.0 ° C), third butyl peroxybutyrate ( 1 minute half-life temperature: 136.1 ° C), 1,1-di(trihexylperoxy)cyclohexane (1 minute half-life temperature: 149.2 ° C), and the like. Among them, in view of particularly excellent self-crosslinking reaction efficiency, it is preferred to use di(4-tert-butylcyclohexyl)peroxycarbonate (1 minute half-life temperature: 92.1 ° C), dilaurin peroxide ( 1 minute half-life temperature: 116.4 ° C)., benzoquinone peroxide (1 minute half-life temperature: 130.0 ° C) and the like.

Further, the half-life of the peroxide is an index indicating the decomposition rate of the peroxide, and is a time until the residual amount of the peroxide becomes half. The decomposition temperature for obtaining the half-life at any time or the half-life time at any temperature is described in the manufacturer catalog, etc., for example, in the "Organic Peroxide Catalogue" of Nippon Oil & Fat Co., Ltd. The 9th edition (May 2003) "etc.

The peroxide may be used singly or in combination of two or more kinds, and the content of the peroxide is 0.01 to 2 parts by weight based on 100 parts by weight of the (meth)acrylic polymer. It is preferably contained in an amount of 0.04 to 1.5 parts by weight, more preferably 0.05 to 1 part by weight. From the viewpoints of adjustment of workability, secondary workability, crosslinking stability, and peelability, it can be suitably selected.

Further, the method for measuring the amount of decomposition of the peroxide remaining after the reaction treatment can be measured, for example, by HPLC (High Performance Liquid Chromatography).

More specifically, for example, about 0.2 g of the reaction-treated adhesive composition may be taken out at a time, immersed in 10 ml of ethyl acetate, and shake-extracted at 25 ° C, 120 rpm for 3 hours with a shaker, and then at room temperature. Allow to stand for 3 days. Then, 10 ml of acetonitrile was added, and the mixture was shaken at 25 ° C, 120 rpm for 30 minutes, and about 10 μl of the extract obtained by filtration through a membrane filter (0.45 μm) was injected into HPLC for analysis as the amount of peroxide after the reaction treatment.

Further, another organic crosslinking agent or a polyfunctional metal chelate compound may be used as the crosslinking agent. Examples of the organic crosslinking agent include an epoxy crosslinking agent and an imide crosslinking agent. The polyfunctional metal chelate is a compound in which a polyvalent metal is covalently bonded or coordinately bonded to an organic compound. Examples of the polyvalent metal atom include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, Ti, and the like. . Examples of the atom in the organic compound which is covalently bonded or coordinately bonded include an oxygen atom and the like. Examples of the organic compound include an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound, and a ketone compound.

The adhesive layer is formed by the above-mentioned crosslinking agent, but when the adhesive layer is formed, it is necessary to adjust the addition amount of all the crosslinking agents, and sufficiently consider the influence of the crosslinking treatment temperature or the crosslinking treatment time.

The crosslinking treatment temperature or the crosslinking treatment time can be adjusted by using a crosslinking agent. The crosslinking treatment temperature is preferably 170 ° C or less.

Further, the crosslinking treatment may be carried out at a temperature at the drying step of the adhesive layer, or may be additionally provided after the drying step.

Further, the crosslinking treatment time can be set in consideration of productivity or workability, and is usually about 0.2 to 20 minutes, preferably about 0.5 to 10 minutes.

Furthermore, other known additives may be contained in the adhesive composition of the present invention. For example, a powder such as a coloring agent or a pigment, a dye, a surfactant, a plasticizer, and a tackifier may be appropriately added depending on the intended use. , surface lubricants, leveling agents, softeners, antioxidants, anti-aging agents, light stabilizers, UV absorbers, polymerization inhibitors, inorganic or organic fillers, metal powders, particulates, foils, and the like. Further, a redox system to which a reducing agent is added may be used within a controllable range.

The adhesive optical member such as the adhesive optical film of the present invention is one in which an adhesive layer is formed on at least one surface of the optical film by the above-mentioned adhesive.

The method of forming the pressure-sensitive adhesive layer is, for example, a method in which the above-described pressure-sensitive adhesive composition is applied to a separator which has been subjected to a release treatment, and the polymerization solvent is dried to form an adhesive layer, and then transferred to an optical film; Alternatively, the above-mentioned adhesive composition is applied onto an optical film, and a method of forming an adhesive layer on an optical film by drying and removing a polymerization solvent or the like is carried out. Among them, when the adhesive is applied, one or more solvents other than the polymerization solvent may be newly added.

Further, an adhesion-promoting layer may be formed on the surface of the optical film, or an adhesive layer may be formed after various easy-to-treat processes such as corona treatment and plasma treatment. Further, it is possible to carry out an easy subsequent treatment on the surface of the adhesive layer.

As a method of forming the adhesive layer, various methods can be employed. Specific examples thereof include a roll coating method, a roll coating method, a gravure coating method, a reverse coating method, a roll brush, a spray coating, a dip roller coating, a bar coating, a knife coating, an air knife coating method, a curtain coating, and a lip. Lip coat, a method such as extrusion coating using a die coater or the like.

The thickness of the adhesive layer is not particularly limited, and is, for example, about 1 to 100 μm. It is preferably 5 to 50 μm, more preferably 10 to 30 μm.

The gel fraction of the adhesive layer of the present invention thus obtained after coating for 1 hour is from 55% to 95%, preferably from 60 to 95%, more preferably from 70 to 95%. Such a gel fraction means that the crosslinking speed is fast, the occurrence of the marking is small, and no pit is formed on the obtained adhesive layer.

When the above-mentioned adhesive layer is exposed, the sheet (separator) can be applied to protect the adhesive layer until it is practically used.

Examples of the constituent material of the separator include a plastic film such as polyethylene, polypropylene, polyethylene terephthalate, or polyester film, a porous material such as paper, cloth, or nonwoven fabric, a mesh, a foamed sheet, and the like. A metal foil, a suitable sheet such as a laminate, or the like is preferably a plastic film from the viewpoint of excellent surface smoothness.

The plastic film is not particularly limited as long as it is a film that can protect the pressure-sensitive adhesive layer, and examples thereof include a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, and a polymethylpentene film. , a polyvinyl chloride film, a vinyl chloride copolymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, an ethylene-vinyl acetate copolymer film, or the like.

The thickness of the spacer is usually 5 to 200 μm, preferably about 5 to 100 μm. Further, the spacer may be subjected to mold release and antifouling treatment using a polyfluorene-based, fluorine-based, long-chain alkyl-based or fatty amide-based release agent, cerium oxide powder or the like, or a coating type or a mixed type. Antistatic treatment such as vapor deposition type. In particular, the surface of the separator can be suitably subjected to a release treatment such as polyoxygen treatment, long-chain alkyl treatment, or fluorine treatment, thereby improving the releasability from the adhesive layer.

Further, the sheet subjected to the release treatment used in the production of the above-mentioned adhesive optical film can be directly used as a spacer for the adhesive optical film, and can be simplified in terms of steps.

The optical film is used in a user who forms an image display device such as a liquid crystal display device, and the type thereof is not particularly limited. For example, a polarizing plate is mentioned as an optical film. The polarizing plate is generally used for one of the polarizing elements or a transparent protective film on both sides.

There is no particular limitation on the polarizing element, and various types can be used. The polarizing element is, for example, a hydrophilic polymer film such as a polyvinyl alcohol film, a partially methylalized polyvinyl alcohol film or an ethylene-vinyl acetate copolymer partially saponified film, and adsorbs iodine or dichroism. A dichroic material such as a dye is uniaxially stretched; a dehydrated material of polyvinyl alcohol or a polyolefin-based alignment film such as a dehydrochlorination treatment of polyvinyl chloride. Among these, a polarizing element comprising a polyvinyl alcohol-based film and a dichroic substance such as iodine is preferred. The thickness of the polarizing element is not particularly limited, but is usually about 5 to 80 μm.

A polarizing element obtained by uniaxially stretching a polyvinyl alcohol-based film by iodine can be produced by, for example, immersing polyvinyl alcohol in an aqueous solution of iodine and dyeing it to a length of 3 to 7 times the original length. It may also be immersed in an aqueous solution of potassium iodide or the like which may contain boric acid or zinc sulfate, zinc chloride or the like as needed. Further, the polyvinyl alcohol-based film may be immersed in water and washed with water before dyeing. By washing the polyvinyl alcohol-based film with water, in addition to cleaning the stain on the surface of the polyvinyl alcohol-based film and the anti-caking agent, it also has the effect of preventing unevenness in dyeing unevenness by swelling the polyvinyl alcohol-based film. . The extension may be carried out after dyeing with iodine, or may be carried out while dyeing, or may be dyed with iodine after stretching. It can also be extended in an aqueous solution of boric acid or potassium iodide or in a water bath.

The optical film used for the adhesive optical film of the present invention is, for example, a polarizing plate. The polarizing plate is generally used for one of the polarizing elements or a transparent protective film on both sides.

The polarizing element is not particularly limited, and various types can be used. The polarizing element is, for example, a hydrophilic polymer film such as a polyvinyl alcohol film, a partially methylalized polyvinyl alcohol film or an ethylene-vinyl acetate copolymer partially saponified film, and adsorbs iodine or dichroism. A dichroic material such as a dye is uniaxially stretched; a dehydrated material of polyvinyl alcohol or a polyolefin-based alignment film such as a dehydrochlorination treatment of polyvinyl chloride. Among these polarizing elements, a polarizing element comprising a polyvinyl alcohol-based film and a dichroic substance such as iodine is preferred. The thickness of the polarizing element is not particularly limited, but is usually about 5 to 80 μm.

A polarizing element obtained by uniaxially stretching a polyvinyl alcohol-based film by iodine can be produced, for example, by immersing polyvinyl alcohol in an aqueous solution of iodine and then stretching it to 3 to 7 times the original length. It may also be immersed in an aqueous solution of potassium iodide or the like which may contain boric acid or zinc sulfate, zinc chloride or the like as needed. Further, it is also possible to immerse the polyvinyl alcohol-based film in water for washing before the dyeing. By washing the polyvinyl alcohol-based film with water, in addition to cleaning the stain on the surface of the polyvinyl alcohol-based film and the anti-caking agent, it also has the effect of preventing unevenness in dyeing unevenness by swelling the polyvinyl alcohol-based film. . The extension may be carried out after dyeing with iodine, or may be carried out while dyeing, or may be dyed with iodine after stretching. It can also be extended in an aqueous solution of boric acid or potassium iodide or in a water bath.

The material constituting the transparent protective film is, for example, a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, moisture barrier property, and isotropic property. Specific examples of such a thermoplastic resin include a cellulose resin such as cellulose triacetate, a polyester resin, a polyether oxime resin, a polyfluorene resin, a polycarbonate resin, a polyamide resin, a polyimide resin, and a poly Olefin resin, (meth)acrylic resin, cyclic polyolefin resin A mixture of an olefinic resin, a polyarylate resin, a polystyrene resin, a polyvinyl alcohol resin, and the like. Further, a transparent protective film is bonded to one side of the polarizing element by the adhesive layer, and a (meth)acrylic, urethane-based, urethane-based, or ring-like ring can be used on the other side. A thermosetting resin such as an oxygen-based or polyfluorene-based or ultraviolet-curable resin is used as a transparent protective film. More than one suitable additive may be contained in the transparent protective film. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a mold release agent, a coloring preventive agent, a flame retardant, a nucleating agent, an antistatic agent, a pigment, a colorant, and the like. The content of the above thermoplastic resin in the transparent protective film is preferably from 50 to 100% by weight, more preferably from 50 to 99% by weight, still more preferably from 60 to 98% by weight, particularly preferably from 70 to 97% by weight. . When the content of the thermoplastic resin in the transparent protective film is 50% by weight or less, the high transparency and the like which the thermoplastic resin originally has cannot be sufficiently exhibited.

Further, as the transparent protective film, a polymer film as described in Japanese Patent Laid-Open Publication No. 2001-343529 (WO 01/37007), for example, contains (A) substituted and/or unbranched on the branch. A resin composition of a substituted imide-based thermoplastic resin and (B) a thermoplastic resin having a substituted and/or unsubstituted phenyl group and a nitrile group on the branch. Specific examples thereof include a film containing a resin composition of an alternating copolymer of isobutylene and N-methylmaleimide and an acrylonitrile/styrene copolymer. As the film, a film formed of a mixed extrusion of a resin composition or the like can be used. Since these films have a small phase difference and a small photoelastic coefficient, the unevenness caused by the deformation of the polarizing plate can be eliminated, and since the moisture permeability is small, the humidifying durability is excellent.

The thickness of the transparent protective film can be appropriately determined, and it is usually about 1 to 500 μm from the viewpoints of workability such as strength and workability, and thin layer properties. In particular, it is preferably from 1 to 300 μm, more preferably from 5 to 200 μm. It is particularly suitable when the transparent protective film is 5 to 150 μm.

Further, when a transparent protective film is provided on both sides of the polarizing element, a protective film formed of the same polymer material may be used on the front and back surfaces, and a protective film formed of a different polymer material or the like may be used.

As the transparent protective film of the present invention, at least one selected from the group consisting of a cellulose resin, a polycarbonate resin, a cyclic polyolefin resin, and a (meth)acrylic resin is preferably used.

The cellulose resin is an ester of cellulose and a fatty acid. Specific examples of such a cellulose ester-based resin include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. Among them, cellulose triacetate is particularly preferred. Many products of cellulose triacetate are commercially available and are advantageous in terms of availability or cost. Examples of commercially available products of cellulose triacetate include the trade names "UV-50", "UV-80", "SH-80", "TD-80U", and "TD-TAC" manufactured by Fujifilm Corporation. "UZ-TAC" or "KC series (series)" manufactured by Konica Corporation. Generally, the in-plane retardation (Re) of the cellulose triacetate is about 0, and the phase difference (Rth) in the thickness direction has about ~60 nm.

Further, the cellulose resin film having a small retardation in the thickness direction can be obtained, for example, by treating the above cellulose resin. For example, a base film such as polyethylene terephthalate coated with a solvent such as cyclopentanone or methyl ethyl ketone, polypropylene or stainless steel may be bonded to a usual cellulose film and dried by heating ( For example, after performing at about 80 to 150 ° C for about 3 to 10 minutes, the substrate film is peeled off; it is dissolved in a solvent such as cyclopentanone or methyl ethyl ketone. A method in which a solution such as an olefin resin or a (meth)acrylic resin is applied onto a usual cellulose resin film and dried by heating (for example, at 80 to 150 ° C for about 3 to 10 minutes), and then the coating film is peeled off. Wait.

Moreover, as the cellulose resin film having a small phase difference in the thickness direction, a fatty acid cellulose-based resin film having a fat substitution degree can be used. In the cellulose triacetate which is usually used, Rth can be reduced by controlling the degree of substitution of acetic acid to about 2.8, preferably by controlling the degree of substitution of acetic acid to 1.8 to 2.7. R41 can be controlled to be small by adding a plasticizer such as dibutyl phthalate, p-toluenesulfonyl aniline or ethyltriethyl citrate to the cellulose-substituted resin. The amount of the plasticizer added is preferably 40 parts by weight or less, more preferably 1 to 20 parts by weight, still more preferably 1 to 15 parts by weight, per 100 parts by weight of the fatty acid cellulose-based resin.

As a specific example of the cyclic polyolefin resin, it is preferred to lower An olefinic resin. The cyclic polyolefin-based resin is a general term for a resin obtained by polymerizing a cyclic olefin as a polymerization unit, and examples thereof include a Japanese Patent Laid-Open No. Hei No. 1-240517, Japanese Patent Laid-Open No. Hei No. Hei No. 3-148882, and Japanese Patent No. The resin described in Kaikai No. 3-122137 or the like. Specific examples thereof include a ring-opening (co)polymer of a cyclic olefin, an addition polymer of a cyclic olefin, a copolymer of a cyclic olefin and an α-olefin such as ethylene or propylene (typically a random copolymer). And a graft copolymer obtained by modifying an unsaturated carboxylic acid or a derivative thereof, and the like, and the like, and the like. Specific examples of the cyclic olefin include a descending An olefinic monomer.

As the cyclic polyolefin resin, various products are commercially available. Specific examples include the trade name "ZEONEX" manufactured by Japan Zeon Co., Ltd., "ZEONOR", the trade name "ARTON" manufactured by JSR Co., Ltd., the trade name "TOPAS" manufactured by TICONA, and Mitsui Chemicals Co., Ltd. The product name "APEL" is manufactured.

The (meth)acrylic resin preferably has a Tg (glass transition temperature) of 115 ° C or more, more preferably 120 ° C or more, still more preferably 125 ° C or more, and particularly preferably 130 ° C or more. When the Tg is 115 ° C or more, the durability of the polarizing plate can be excellent. The upper limit of the Tg of the (meth)acrylic resin is not particularly limited, and is preferably 170 ° C or less from the viewpoint of moldability. A film having an in-plane retardation (Re) and a thickness direction retardation (Rth) of substantially 0 can be obtained from the (meth)acrylic resin.

As the (meth)acrylic resin, any suitable (meth)acrylic resin can be used within a range that does not impair the effects of the present invention. For example, poly(meth)acrylate such as polymethyl methacrylate, methyl methacrylate-(meth)acrylic acid copolymer, methyl methacrylate-(meth) acrylate copolymer, methacrylic acid Methyl ester-acrylate-(meth)acrylic acid copolymer, methyl (meth)acrylate-styrene copolymer (MS resin, etc.), polymer having an alicyclic hydrocarbon group (for example, methyl methacrylate-methyl Cyclohexyl acrylate copolymer, methyl methacrylate-(meth) acrylate Ester copolymers, etc.).

Preferred is a poly(meth)acrylic acid C1-6 alkyl ester such as poly(methyl) acrylate. More preferably, it is a methyl methacrylate-based resin containing methyl methacrylate as a main component (50 to 100% by weight, preferably 70 to 100% by weight).

Specific examples of the (meth)acrylic resin include, for example, Acrypet VH or Acrypet VRL 20A manufactured by Mitsubishi Rayon Co., Ltd., and a cyclic structure in the molecule described in JP-A-2004-70296. An acrylic resin, a high Tg (meth)acrylic resin system obtained by intramolecular crosslinking or intramolecular cyclization.

As the (meth)acrylic resin, a (meth)acrylic resin having a lactone ring structure can also be used. The reason for this is high heat resistance, high transparency, and high mechanical strength by biaxial stretching.

Examples of the (meth)acrylic resin having a lactone ring structure include JP-A-2000-230016, JP-A-2001-151814, JP-A-2002-120326, and JP-A. A (meth)acrylic resin having a lactone ring structure described in JP-A-2005-146084, and the like.

The (meth)acrylic resin having a lactone ring structure preferably has a pseudo ring structure represented by the following formula (Chemical Formula 1):

[Chemical 1]

In the formula, R ¹ , R ² and R ³ are each independently and represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms. Further, the organic residue may also include an oxygen atom.

In the structure of the (meth)acrylic resin having a lactone ring structure, the content of the lactone ring structure represented by the formula (Chemical Formula 1) is preferably from 5 to 90% by weight, more preferably from 10 to 8% by weight. 70% by weight, further preferably 10 to 60% by weight, particularly preferably 10 to 50% by weight. In the structure of the (meth)acrylic resin having a lactone ring structure, when the content ratio of the lactone ring structure represented by the formula (Chemical Formula 1) is less than 5% by weight, heat resistance and solvent resistance are exhibited. The surface hardness becomes insufficient. In the structure of the (meth)acrylic resin having a lactone ring structure, if the content ratio of the lactone ring structure represented by the formula (Chemical Formula 1) is more than 90% by weight, the molding processability may be insufficient. Hey.

The mass average molecular weight (sometimes referred to as a weight average molecular weight) of the (meth)acrylic resin having a lactone ring structure is preferably from 1,000 to 2,000,000, more preferably from 5,000 to 1,000,000, and even more preferably from 10,000 to 10,000. 500000, especially good is 50000~500000. If the mass average molecular weight is outside the above range, it is considered to be inferior in terms of mold processability.

The (meth)acrylic resin having a lactone ring structure preferably has a Tg of 115 ° C or more, more preferably 120 ° C or more, still more preferably 125 ° C or more, and particularly preferably 130 ° C or more. Since the Tg is 115° C. or higher, for example, when it is incorporated into a polarizing plate as a transparent protective film, it is excellent in durability. The upper limit of the Tg of the (meth)acrylic resin having the above lactone ring structure is not particularly limited, and is preferably 170 ° C or less from the viewpoint of moldability and the like.

The (meth)acrylic resin having a lactone ring structure, the higher the total light transmittance measured by the method of ASTM-D-1003, by using the molded article obtained by injection molding, is preferably 85% or more. More preferably, it is 88% or more, and even more preferably 90% or more. The total light transmittance is a standard of transparency. If the total light transmittance is less than 85%, the transparency is lowered.

As the transparent protective film, a film having a front phase difference of less than 40 nm and a thickness direction retardation of less than 80 nm is generally used. The front phase difference Re is represented by Re = (nx - ny) × d. The thickness direction phase difference Rth is represented by Rth = (nx - nz) × d. Further, the Nz coefficient is expressed by Nz = (nx - nz) / (nx - ny). [The refractive index of the slow axis direction, the fast axis direction, and the thickness direction of the film are respectively nx, ny, nz, and d (nm) is the thickness of the film. The direction of the slow axis is the direction in which the refractive index in the film plane becomes the largest]. Further, it is preferred that the transparent protective film be as colored as possible. A protective film having a phase difference in the thickness direction of -90 nm to +75 nm can be preferably used. By using a protective film having a phase difference (Rth) in the thickness direction of -90 nm to +75 nm, the polarizing plate coloring (optical coloring) caused by the transparent protective film can be substantially eliminated. The thickness direction retardation (Rth) is further preferably -80 nm to +60 nm, particularly preferably -70 nm to +45 nm.

On the other hand, as the transparent protective film, a phase difference plate having a front phase difference of 40 nm or more and/or a thickness direction retardation of 80 nm or more can be used. The front phase difference is usually controlled within the range of 40 to 200 nm, and the thickness direction phase difference is usually controlled within the range of 80 to 300 nm. When a phase difference plate is used as the transparent protective film, the phase difference plate also functions as a transparent protective film, so that the thickness can be reduced.

Examples of the retardation film include a birefringent film obtained by subjecting a polymer material to uniaxial or biaxial stretching treatment, an alignment film of a liquid crystal polymer, and an alignment layer supporting a liquid crystal polymer. The thickness of the phase difference plate is not particularly limited and is usually about 20 to 150 μm.

Examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, and poly. Carbonate, polyarylate, polyfluorene, polyethylene terephthalate, polyethylene naphthalate, polyether oxime, polyphenylene sulfide, polyphenylene ether, polyallyl fluorene, polyamine, Polyimine, polyolefin, polyvinyl chloride, cellulose resin, cyclic polyolefin resin The olefinic resin) or a binary system or a ternary system of various copolymers, graft copolymers, mixtures, and the like. These polymer materials can be an alignment (stretching film) by stretching or the like.

Examples of the liquid crystal polymer include various types of polymers such as a main chain type or a branched type in which a conjugated linear atomic group (mesogene) which imparts liquid crystal alignment properties is introduced into a main chain or a branch of a polymer. . Specific examples of the liquid crystal polymer of the main chain type include, for example, a nematic alignment polyester-based liquid crystal polymer having a structure in which a liquid crystal priming unit is bonded to a space portion to which flexibility is provided, and a disk-shaped polymerization. Or a cholesterol type polymer or the like. Specific examples of the branched-type liquid crystal polymer include compounds in which a polysiloxane, a polyacrylate, a polymethacrylate or a polymalonate is used as a main chain skeleton, and a conjugated atomic group is contained. The spacer has a liquid crystal original portion including a para-substituted cyclic compound unit imparting nematic alignment as a branch. The liquid crystal polymer is treated, for example, by a method of rubbing the surface of a film such as polyimide or polyvinyl alcohol formed on a glass plate, and oxidizing the ruthenium oxide by oblique deposition. On the treated surface, a solution of the liquid crystalline polymer is spread and then heat-treated.

The phase difference plate may be, for example, a variety of wavelength plates or a phase difference plate for compensating for coloring or viewing angle caused by birefringence of the liquid crystal layer, etc., and may have a suitable phase difference corresponding to the purpose of use, or may be two or more layers. The phase difference plate is used to control optical characteristics such as phase difference.

The phase difference plate satisfies the relationship of nx=ny>nz, nx>ny>nz, nx>ny=nz, nx>nz>ny, nz=nx>ny, nz>nx>ny, nz>nx=ny, according to Choose for a variety of uses. Furthermore, the so-called ny=nz is not only the case where ny and nz are completely the same, but also the case where ny and nz are substantially the same.

For example, a phase difference plate satisfying nx>ny>nz is preferably used in which the front phase difference is 40 to 100 nm, the thickness direction phase difference is 100 to 320 nm, and the Nz coefficient is 1.8 to 4.5. For example, a positive phase plate (positive A-plate) satisfying nx>ny=nz is preferably used to satisfy a front phase difference of 100 to 200 nm. For example, a phase difference plate (negative A-plate) satisfying nz=nx>ny is preferably used to satisfy a front phase difference of 100 to 200 nm. For example, a phase difference plate satisfying nx>nz>ny is preferably used to satisfy a front phase difference of 150 to 300 nm and an Nz coefficient of more than 0 and 0.7 or less. Further, as described above, for example, nx=ny>nz, nz>nx>ny, or nz>nx=ny can be used.

The transparent protective film can be suitably selected depending on the liquid crystal display device to be applied. For example, in the case of VA (Vertical Alignment, including MVA or PVA), it is preferred that at least one of the polarizing plates (unit side) has a phase difference. As a specific phase difference, a range of Re=0 to 240 nm and Rth=0 to 500 nm is preferable. In terms of the three-dimensional refractive index, it is preferable that nx>ny=nz, nx>ny>nz, nx>nz>ny, nx=ny>nz (positive A plate, biaxial, negative C plate). Regarding the VA type, it is preferred to use a combination of a positive A plate and a negative C plate, or a piece of biaxial film. When the polarizing plate is used above and below the liquid crystal cell, the liquid crystal cell may have a phase difference both above and below, or may have any phase difference between the upper and lower transparent protective films.

For example, in the case of IPS (In-Plane Switching, including FFS), it can be used when the transparent protective film on one of the polarizing plates has a phase difference. For example, in the case where there is no phase difference, it is preferable that the liquid crystal cell does not have a phase difference above (the unit side). In the case of having a phase difference, it is preferable to have a phase difference between the upper and lower sides of the liquid crystal cell, and a case where the upper and lower sides have a phase difference (for example, the upper side is a biaxial film satisfying the relationship of nx>nz>ny, There is no phase difference on the side, or the upper side is a positive A plate and the lower side is a positive C plate). In the case of having a phase difference, a range of Re = -500 to 500 nm and Rth = -500 to 500 nm is preferred. In terms of the three-dimensional refractive index, nx>ny=nz, nx>nz>ny, nz>nx=ny, nz>nx>ny (positive A plate, biaxial, positive C plate) are preferred.

Further, the film having the phase difference described above can be bonded to a transparent protective film having no phase difference to impart the above function.

The transparent protective film may be subjected to a surface modification treatment to improve adhesion to the polarizing element before the application of the adhesive. Specific treatments include corona treatment, plasma treatment, flame treatment, ozone treatment, primer treatment, glow treatment, saponification treatment, treatment with a coupling agent, and the like. Further, an antistatic layer can be suitably formed.

The transparent protective film may be a surface of the polarizing element, and may be a hard coat layer or a processor for antireflection treatment, anti-adhesive treatment, diffusion or anti-glare.

The purpose of the hard coat treatment is to prevent the surface of the polarizing plate from being damaged. For example, the surface of the transparent protective film is excellent in hardness and sliding properties by a suitable ultraviolet curable resin such as acrylic or polyoxygen. It is formed by hardening a film or the like. The purpose of performing the anti-reflection treatment is to prevent external light from being reflected on the surface of the polarizing plate, and it can be achieved by forming a conventional anti-reflection film or the like. Further, the purpose of performing the anti-sticking treatment is to prevent adhesion to an adjacent layer (for example, a diffusing plate on the backlight side).

Moreover, the purpose of performing the anti-glare treatment is to prevent the external light from being reflected on the surface of the polarizing plate and to interfere with the identification of the transmitted light of the polarizing plate, for example, by roughening the blasting method or the embossing method or blending the transparent particles. A suitable method such as a method is formed by imparting a fine uneven structure to the surface of the transparent protective film. As the fine particles contained in the formation of the surface fine uneven structure, for example, cerium oxide, aluminum oxide, titanium oxide, zirconium oxide, tin oxide, indium oxide, cadmium oxide, cerium oxide, or the like having an average particle diameter of 0.5 to 20 μm can be used. Transparent fine particles such as inorganic fine particles having conductivity, organic fine particles composed of a crosslinked or uncrosslinked polymer, or the like. When the surface fine uneven structure is formed, the amount of the fine particles used is usually from about 2 to 70 parts by weight, preferably from 5 to 50 parts by weight, per 100 parts by weight of the transparent resin forming the surface fine uneven structure. The anti-glare layer may also function to diffuse the transmitted light of the polarizing plate to expand a diffusion layer (such as a viewing angle expansion function) such as a viewing angle.

Further, the antireflection layer, the anti-adhesion layer, the diffusion layer, the antiglare layer, and the like may be provided separately from the transparent protective film as the other optical layer, in addition to the transparent protective film itself.

An adhesive is used in the subsequent treatment of the above polarizing element and the transparent protective film. Examples of the adhesive agent include an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, a vinyl latex-based, and an aqueous polyester. The above-mentioned adhesive is usually used as an adhesive containing an aqueous solution, and usually contains 0.5 to 60% by weight of a solid component. In addition to the above, examples of the adhesive for the polarizing element and the transparent protective film include an ultraviolet curable adhesive, an electron beam curable adhesive, and the like. The adhesive for an electron beam curing type polarizing plate exhibits suitable adhesion to the above various transparent protective films. Further, the adhesive used in the present invention may contain a metal compound filler.

Further, examples of the optical film include a reflector or a semi-transmissive plate, a phase difference plate (including a 1/2 or 1/4 wavelength plate), a viewing angle compensation film, and a brightness enhancement film equal to the formation of a liquid crystal display device or the like. Optical layer. These may be used alone as an optical film, or may be laminated on the above polarizing plate in one or two or more layers in practical use.

Particularly preferred is a reflective polarizing plate or a semi-transmissive polarizing plate which is formed by laminating a reflecting plate or a semi-transmissive reflecting plate on a polarizing plate; and an elliptically polarizing plate or a circular polarizing plate which is formed by laminating a phase difference plate on a polarizing plate. A wide viewing angle polarizing plate formed by laminating a viewing angle compensation film on a polarizing plate, or a polarizing plate formed by laminating a brightness enhancement film on a polarizing plate.

The reflective polarizing plate is formed by providing a reflective layer on a polarizing plate, and can be used to form a liquid crystal display device of a type that reflects incident light from the identification side (display side) for display, and has a light source such as a backlight that can be omitted. Therefore, the advantages of thinning of the liquid crystal display device and the like can be easily achieved. The formation of the reflective polarizing plate can be carried out by, for example, a method in which a transparent protective layer is equal to a reflective layer containing a metal or the like on one surface of the polarizing plate.

Specific examples of the reflective polarizing plate include a foil or a vapor deposited film containing a reflective metal such as aluminum on one surface of the transparent protective film subjected to the matte treatment to form a reflective layer. In addition, a reflective layer having a fine uneven structure on the surface and having a fine uneven structure on the surface of the transparent protective film may be used. The reflective layer of the fine uneven structure described above diffuses incident light by diffuse reflection, thereby preventing directionality or appearance from being bright, and has the advantage of suppressing unevenness in brightness and the like. Further, the transparent protective film containing fine particles also has an advantage of further suppressing unevenness of light and dark when the incident light and the reflected light thereof are transmitted therethrough. The formation of the reflective layer of the fine uneven structure reflecting the fine uneven structure on the surface of the transparent protective film can be formed on the surface of the transparent protective layer by a vacuum evaporation method, an ion plating method, a sputtering method, or a plating method, for example. It is carried out by directly attaching a metal method or the like.

Instead of attaching the reflecting plate directly to the transparent protective film of the polarizing plate, a reflective layer may be provided on a suitable film based on the transparent film to form a reflective sheet or the like. Further, since the reflective layer usually contains a metal, it is preferably a transparent protective film or a polarized light from the viewpoint of preventing a decrease in reflectance due to oxidation, thereby maintaining the initial reflectance for a long period of time or avoiding a separate protective layer. A plate or the like covers the use form of the reflecting surface.

Further, the semi-transmissive polarizing plate can be obtained by forming a semi-transmissive reflective layer such as a half mirror which reflects light by the reflective layer and transmits the light. The semi-transmissive polarizing plate is usually provided on the back side of the liquid crystal cell, and can form a liquid crystal display device of the following type, that is, when a liquid crystal display device or the like is used in a relatively bright environment, reflection is from the identification side (display side). An image is displayed by incident light, and an image is displayed using a built-in light source such as a backlight built in the back surface of the semi-transmissive polarizing plate in a relatively dark environment. That is, the semi-transmissive polarizing plate is useful in the formation of a liquid crystal display device or the like of the following types, that is, the energy used for a light source such as a backlight can be saved in a bright environment, and the built-in light source can be used in a relatively dark environment.

An elliptically polarizing plate or a circularly polarizing plate in which a phase difference plate is laminated on a polarizing plate will be described. When the linearly polarized light is changed to elliptically polarized or circularly polarized light, or the elliptically polarized or circularly polarized light is changed to linearly polarized light, or the polarized direction of the linearly polarized light is changed, a phase difference plate or the like can be used. In particular, as a phase difference plate which changes linearly polarized light into circularly polarized light or changes circularly polarized light into linearly polarized light, a so-called quarter-wave plate (also referred to as a λ/4 plate) can be used. A 1/2 wavelength plate (also known as a λ/2 plate) is commonly used to change the direction of polarization of linearly polarized light.

The elliptically polarizing plate can be effectively used in the case of compensating (preventing) the coloring (blue or yellow) of the liquid crystal layer of the super twisted nematic (STN) type liquid crystal display device due to birefringence, thereby performing the coloring without the above coloring. The situation of black and white display, etc. Further, it is preferable to control the three-dimensional refractive index to compensate (prevent) the coloring which occurs when the screen of the liquid crystal display device is viewed obliquely. The circularly polarizing plate can be effectively used, for example, in the case of adjusting the color tone of an image of a reflective liquid crystal display device that displays an image in color, and also has a function of preventing reflection.

Further, the elliptically polarizing plate or the reflective elliptically polarizing plate is formed by laminating a polarizing plate, a reflective polarizing plate, and a phase difference plate as appropriate. The elliptically polarizing plate or the like may be formed by sequentially laminating (reflective) polarizing plates and phase difference plates in the manufacturing process of the liquid crystal display device, so as to be a combination of a (reflective) polarizing plate and a phase difference plate, as described above. When it is formed in advance as an optical film such as an elliptically polarizing plate, it is excellent in quality stability or lamination workability, and the like, and has an advantage that the manufacturing efficiency of a liquid crystal display device or the like can be improved.

The viewing angle compensation film system makes the image appear clear and is used to enlarge the film of the viewing angle even when the screen of the liquid crystal display device is viewed from a direction that is not perpendicular to the screen. Such a viewing angle compensation retardation plate includes, for example, an alignment film such as a retardation film or a liquid crystal polymer, or an alignment layer such as a liquid crystal polymer supported on a transparent substrate. In the conventional phase difference plate, a polymer film having birefringence which is uniaxially stretched in the plane direction thereof is used, and in contrast, a phase difference plate serving as a viewing angle compensation film is used to have a biaxial extension in the plane direction thereof. a polymer film having birefringence, a biaxially stretched film such as a birefringent polymer having a controllable thickness direction and a biaxially stretched film extending in a thickness direction thereof and extending in a thickness direction thereof . Examples of the oblique alignment film include a stretching treatment or a shrinkage treatment of the polymer film, or a tilting of the liquid crystal polymer, by a shrinkage force generated by heating after the heat shrink film is applied to the polymer film. Orientation, etc. As the raw material polymer of the phase difference plate, the same as the polymer described in the above phase difference plate can be used, and it can be used to prevent coloring due to a change in the recognition angle due to the phase difference of the liquid crystal cell. Or expand the visibility of a good perspective, etc. for the purpose of the appropriate.

Further, from the viewpoint of achieving a wide viewing angle with good visibility, it is preferable to use an optical difference in supporting an alignment layer containing a liquid crystal polymer, particularly an inclined alignment layer of a discotic liquid crystal polymer, with a cellulose triacetate film. The optical compensation phase difference plate of the tropism layer.

A polarizing plate in which a polarizing plate and a brightness improving film are bonded together is usually provided on the back side of the liquid crystal cell. In the brightness-increasing film system, when natural light is incident due to backlighting of a liquid crystal display device or the like, or reflection from the back side, linear polarization of a specific polarization axis or circularly polarized light of a specific direction is reflected, and other light is transmitted, so that brightness is obtained. The polarizing plate in which the film and the polarizing plate are laminated can increase the transmitted light from a light source such as a backlight to obtain a transmitted light of a specific polarized state, and the light other than the specific polarized state is reflected without being transmitted. Further, the light reflected by the brightness-increased film surface is inverted by a reflection layer provided on the rear side thereof, and is again incident on the brightness enhancement film, and a part or all of the light is transmitted in a specific polarization state, thereby increasing The light of the film is increased by the brightness, and the polarizing element is provided with a polarized light that is hard to be absorbed, thereby increasing the amount of light that can be utilized in liquid crystal display image display or the like, thereby improving the brightness. In other words, when the light is incident on the back side of the liquid crystal cell without using the brightness enhancement film and the light is incident from the back side of the liquid crystal cell, the light having the polarization direction that does not coincide with the polarization axis of the polarizing element is substantially absorbed by the polarizing element. Therefore, the polarizing element cannot be transmitted. That is, although it differs depending on the characteristics of the polarizing element to be used, about 50% of the light is absorbed by the polarizing element, so that the amount of light usable in liquid crystal image display or the like is reduced, and the image is darkened. The brightness enhancement film is repeatedly operated such that light having a polarization direction that can be absorbed by the polarizing element is not incident on the polarizing element, but is reflected on the brightness enhancement film, and further reflected by the rear side. When the layer or the like is reversed and is incident on the brightness enhancement film again, the brightness enhancement film changes the polarization direction of the light reflected and inverted between the two to be transmitted through the polarization direction of the polarization direction of the polarizing element. Since it is supplied to the polarizing element, it is possible to effectively use light such as a backlight in the image display of the liquid crystal display device, and the screen can be made bright.

A diffusion plate may be provided between the brightness enhancement film and the reflective layer or the like. The light in the polarized state reflected by the brightness enhancement film is directed toward the reflection layer or the like, and the diffusing plate provided is capable of uniformly diffusing the passing light while eliminating the polarization state to be in a non-polarized state. In other words, the operation is repeated such that the light in the natural light state is reflected on the reflective layer or the like, reflected by the reflective layer or the like, and then again incident on the brightness enhancement film through the diffusion plate. By providing a diffusing plate between the brightness improving film and the reflective layer or the like to restore the polarized light to the original natural light, the brightness of the display screen can be maintained, and the unevenness of the brightness of the display screen can be reduced, thereby providing a uniform and bright picture. . By providing the diffusion plate, the number of repeated reflections of the primary incident light can be appropriately increased, and the diffusion function of the diffusion plate can be used to provide a uniform and bright display screen.

As the brightness-enhancing film, for example, a multilayer film of a dielectric or a multilayer laminated body of a film having different refractive index anisotropy, which exhibits a characteristic of transmitting a linearly polarized light of a predetermined polarization axis and reflecting other light, may be used. The alignment film of the cholesteric liquid crystal polymer or the one which supports the alignment liquid crystal layer on the film substrate or the like which exhibits a characteristic of polarizing light of either of left-handed or right-handed rotation and transmitting other light is suitable.

Therefore, by using the brightness enhancement film of the type that transmits the linearly polarized light of the predetermined polarization axis, the transmitted light is incident on the polarizing plate directly in the direction coincident with the polarization axis, thereby suppressing the absorption loss caused by the polarizing plate. At the same time, the light is transmitted efficiently. On the other hand, a brightness enhancement film of a type that transmits circularly polarized light such as a cholesteric liquid crystal layer can directly enter light onto the polarizing element, but it is preferable to pass the phase difference from the viewpoint of suppressing absorption loss. The plate linearly polarizes the circularly polarized light so that it is incident on the polarizing plate. Further, by using a quarter-wave plate as the phase difference plate, circularly polarized light can be converted into linearly polarized light.

A phase difference plate which can function as a quarter-wave plate in a wide wavelength range such as a visible light region can be obtained, for example, by using a light-wavelength light having a wavelength of 550 nm to function as a quarter-wave plate. The phase difference plate and the phase difference layer which exhibits other phase difference characteristics are, for example, a method in which a phase difference layer functioning as a 1/2 wavelength plate overlaps. Therefore, the phase difference plate disposed between the polarizing plate and the brightness enhancement film includes one or two or more layers of retardation layers.

Further, in the case of a cholesteric liquid crystal layer, it is also possible to combine two or three or more layers with different reflection wavelengths, thereby obtaining a circular polarizer in a wide wavelength range such as a visible light region. Based on this, a transmissive circular polarization of a wider wavelength range is obtained.

Further, the polarizing plate may include a polarizing plate and two or more optical layers stacked as in the polarizing-separating polarizing plate. Therefore, a reflective elliptically polarizing plate or a semi-transmissive elliptically polarizing plate in which the above-described reflective polarizing plate or semi-transmissive polarizing plate and retardation plate are combined may be used.

The optical film in which the optical layer is laminated on the polarizing plate can be formed by sequentially laminating layers in the manufacturing process of a liquid crystal display device or the like. However, the optical film is laminated in advance to be excellent in quality stability and assembly work. There is an advantage that the manufacturing steps of the liquid crystal display device and the like can be improved. A suitable bonding method such as an adhesive layer can be used for the laminate. When the polarizing plate and the other optical layers are continued, the optical axes thereof can be appropriately arranged according to the target phase difference characteristics and the like.

Further, on each layer such as an optical film or an adhesive layer of the adhesive optical film of the present invention, for example, a salicylate-based compound or a benzophenol-based compound, a benzotriazole-based compound or a cyanoacrylate is used. A method of treating an ultraviolet absorber such as a compound or a nickel-miss salt compound to have an ultraviolet absorbing ability or the like.

The adhesive optical film of the present invention can be suitably used for formation of various image display devices such as liquid crystal display devices. The liquid crystal display device can be formed according to the previous method. In other words, the liquid crystal display device can be generally incorporated in a drive circuit or the like by suitably combining a liquid crystal cell, an adhesive optical film, and a component such as an illumination system as needed, and in the present invention, in addition to the adhesive of the present invention. The optical film is not particularly limited and can be formed according to the conventional method. As the liquid crystal cell, any type such as a TN type, an STN type, a π type, a VA type, or an IPS type can also be used.

A liquid crystal display device in which an adhesive optical film is disposed on one side or both sides of a liquid crystal cell, or a liquid crystal display device such as a backlight or a reflector used in an illumination system can be formed. In this case, the optical film of the present invention may be disposed on one side or both sides of the liquid crystal cell. When the optical film is placed on both sides, the same may be the same or different. Further, when forming a liquid crystal display device, one or two or more layers such as a diffusion plate, an antiglare layer, an antireflection film, a protective plate, a tantalum array, a lens array plate, a light diffusing plate, and a backlight can be disposed at appropriate positions. And other suitable components.

Next, an organic electroluminescence device (organic EL display device) will be described. The optical film (polarizing plate or the like) of the present invention can also be applied to an organic EL display device. In general, an organic EL display device is formed by sequentially laminating a transparent electrode, an organic light-emitting layer, and a metal electrode on a transparent substrate to form an illuminant (organic electroluminescence). In particular, the organic light-emitting layer is a laminate of various organic thin films, and for example, a laminate comprising a hole implant layer such as a triphenylamine derivative and a light-emitting layer containing a fluorescent organic solid such as ruthenium or the like is known. The laminate of the light-emitting layer and the electron-implanting layer containing an anthracene derivative or the like, or a combination of the layer of the hole, the layer of the light-emitting layer, and the layer of the electron-embedded layer.

The organic EL display device emits light according to the principle that a voltage is applied to the transparent electrode and the metal electrode, and holes and electrons are implanted in the organic light-emitting layer, and the energy generated by the recombination of the holes and the electrons is generated. The fluorescent substance is excited, and the excited fluorescent material emits light when it returns to the ground state. The recombination mechanism in the middle is the same as that of a normal diode, and it can be inferred that the current and the luminescence intensity show a strong nonlinearity accompanying the rectification for the applied voltage.

In the organic EL display device, at least one of the electrodes must be transparent in order to take out the light emission in the organic light-emitting layer, and a transparent electrode formed of a transparent conductor such as indium tin oxide (ITO) is usually used as an anode. On the other hand, in order to improve the light-emitting efficiency in order to facilitate the electron-carrying, it is important to use a material having a small work function in the cathode, and a metal electrode such as Mg-Ag or Al-Li is usually used.

In the organic EL display device thus constituted, the organic light-emitting layer is formed of an extremely thin film having a thickness of about 10 nm. Therefore, the organic light-emitting layer also makes the light substantially completely transmitted like the transparent electrode. As a result, when light is emitted from the surface of the transparent substrate and is transmitted through the transparent electrode and the organic light-emitting layer, the light reflected from the metal electrode is again emitted toward the surface side of the transparent substrate, so that the display of the organic EL display device is performed when the light is recognized from the outside. The face is like a mirror.

In an organic EL display device including an organic electroluminescence device as described below, a polarizing plate may be disposed on a surface side of the transparent electrode, and a phase difference plate may be disposed between the transparent electrode and the polarizing plate. In the illuminant, a transparent electrode is provided on the surface side of the organic light-emitting layer that emits light by applying a voltage, and a metal electrode is provided on the back side of the organic light-emitting layer.

Since the retardation plate and the polarizing plate have a function of polarizing light reflected from the outside and reflected by the metal electrode, the polarizing action has an effect that the mirror surface of the metal electrode cannot be recognized from the outside. In particular, when the retardation plate is formed by a quarter-wavelength plate and the angle between the polarizing plate and the polarization direction of the phase difference plate is adjusted to π/4, the mirror surface of the metal electrode can be completely shielded.

In other words, the external light incident on the organic EL display device transmits only the linearly polarized light component due to the polarizing plate. This linearly polarized light is usually converted into elliptically polarized light by a phase difference plate, and is generally circularly polarized when the phase difference plate is a quarter wave plate and the angle between the polarizing plate and the polarization direction of the phase difference plate is π/4.

The circularly polarized light passes through the transparent substrate, the transparent electrode, and the organic thin film, is reflected on the metal electrode, passes through the organic film, the transparent electrode, and the transparent substrate again, and becomes linearly polarized again on the phase difference plate. Since the linearly polarized light is orthogonal to the polarizing direction of the polarizing plate, the polarizing plate cannot be transmitted. As a result, the mirror surface of the metal electrode can be completely shielded.

[Examples]

Hereinafter, the invention will be specifically described by way of examples, but the invention is not limited to the examples. Furthermore, the parts and % in each case are based on weight. The evaluation items in the examples and the like were measured in the following manner.

<Measurement of Weight Average Molecular Weight>

The weight average molecular weight of the obtained (meth)acrylic polymer can be measured by GPC (gel permeation chromatography). The sample was prepared by dissolving a sample in dimethylformamide to prepare a 0.1% by weight solution, and after allowing it to stand overnight, the resulting filtrate was filtered through a 0.45 μm membrane filter.

‧Analytical device: manufactured by Tosoh, HLC-8120GPC

‧Tube: manufactured by Tosoh, Super AWM-H, AW4000, AW2500

‧Tube size: each 6.0mmΦ×150mm

‧ Dissolution: 30 mM lithium bromide, 30 mM-phosphoric acid dimethylformamide solution

‧Flow: 0.4ml/min

‧Detector: Differential Refractometer (RI)

‧column temperature: 40 ° C

‧Injection amount: 20μl

(production of polarizing plate)

A polyvinyl alcohol film having a thickness of 80 μm was stretched three times while being dyed in an iodine solution at a concentration of 30 ° C and a concentration of 0.3% at a speed ratio of 1 minute. Thereafter, the film was immersed in an aqueous solution containing 4% of boric acid and 10% of potassium iodide at 60 ° C for 0.5 minutes, and the total stretching ratio was 6 times. Then, it was washed by immersing in an aqueous solution containing potassium iodide at a concentration of 1.5% at 30 ° C for 10 seconds, and then dried at 50 ° C for 4 minutes to obtain a polarizing element. A polarizing plate was formed by laminating a 80 μm-thick cellulose triacetate film having a saponification treatment on both surfaces of the polarizing element by a polyvinyl alcohol-based adhesive.

Manufacturing example 1

<Preparation of acrylic polymer>

In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a cooler, 99.1 parts of butyl acrylate, 0.1 parts of N,N-dimethylaminoethyl acrylate, 0.3 parts of acrylic acid, and 4-hydroxy acrylate were charged. 0.5 part of butyl ester, 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator, and 200 parts of ethyl acetate, nitrogen gas was introduced while stirring slowly, and after the nitrogen substitution, the liquid in the flask was introduced. The temperature was maintained at around 60 ° C, and polymerization was carried out for 6 hours to prepare an acrylic polymer solution. The weight average molecular weight of the above acrylic polymer was 2.05 million.

Manufacturing example 2~25

In the production example 1, an acrylic polymer solution was prepared in the same manner as in Production Example 1 except that at least one of the type and amount of the monomer component and the solvent were changed as shown in Table 1. The weight average molecular weight of the acrylic polymer obtained in each example is shown in Table 1.

Example 1

(Production of polarizing plate with adhesive layer)

The polyol-modified hexamethylene diisocyanate (manufactured by Mitsui Takeda Polyurethane Co., Ltd., D160N) as a crosslinking agent was blended with 0.35 parts, and 100 parts of the solid content of the acrylic polymer solution obtained in Production Example 1. 0.2 part of a decane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., KBM573) was prepared to prepare an acrylic adhesive solution.

Then, the above-mentioned acrylic adhesive solution was applied to one side of a poly(ethylene terephthalate) (PET) film (MRF38 manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.) which was subjected to polyfluorination treatment, and dried. The thickness of the adhesive layer was 20 μm and dried at 155 ° C for 3 minutes to form an adhesive layer. The adhesive layer was bonded to a polarizing plate and transferred to prepare a polarizing plate with an adhesive layer.

Examples 2 to 25 and Comparative Examples 1 to 12

In the first embodiment, as shown in Table 2, the type of the acrylic polymer solution used in the preparation of the acrylic pressure-sensitive adhesive solution, the type or amount of the crosslinking agent, and the type or amount of the decane coupling agent were changed. A polarizing plate with an adhesive layer was produced in the same manner as in Example 1 except for the above.

The polarizing plate (sample) with the adhesive layer obtained in the above Examples and Comparative Examples was subjected to the following evaluation. The evaluation results are shown in Table 2.

<Measurement of initial adhesion force>

The above sample was cut into a width of 25 mm, and adhered to a 0.7 mm thick alkali-free glass (manufactured by Corning Co., Ltd., 1737) by a 2 kg roller in a reciprocating manner, and placed in an autoclave at 50 ° C and 0.5 MPa. It was treated for 15 minutes and then aged at 23 ° C for 1 hour. The adhesion (N/25 mm) at the time of peeling the sample at a peeling angle of 180° and a peeling speed of 300 mm/min by a tensile tester was measured. The treatment with an autoclave at 50 ° C and 0.5 MPa for 15 minutes was carried out in the autoclave treatment when the adhesive optical film was attached to a liquid crystal cell or the like.

<60 ° C / 48 hours after the determination of the adhesion>

The above sample was cut into a width of 25 mm, and adhered to a 0.7 mm thick alkali-free glass (manufactured by Corning Co., Ltd., 1737) by a 2 kg roller in a reciprocating manner, and placed in an autoclave at 50 ° C and 0.5 MPa. It was treated for 15 minutes and then aged at 60 ° C for 48 hours. The adhesion (N/25 mm) at the time of peeling the sample at a peeling angle of 180° and a peeling speed of 300 mm/min by a tensile tester was measured.

<Secondary workability>

The above sample was cut into a width of 25 mm, and adhered to a 0.7 mm thick alkali-free glass (manufactured by Corning Co., Ltd., 1737) by a 2 kg roller, followed by aging at 23 ° C for 1 hour. The adhesion force (N/25 mm) at the peeling angle of 180° and the peeling speed of 300 mm/min at the peeling angle of 180°/min and the state of the glass surface were visually evaluated by the following reference.

◎: It can be peeled off without adhesive residue (continuation force: less than 10N/25mm).

○: It was possible to peel off without sticking of the adhesive, but the peeling was slightly difficult (the force was 10 N/25 mm or more and less than 15 N/25 mm).

△: It was possible to peel off without sticking to the adhesive, but it was difficult to peel off (the adhesive force was 15 N/25 mm or more).

×: There is a slight stickiness of the glue.

××: Adhesive residue occurred.

<Measurement of gel fraction>

The gel fraction was evaluated by using it in the composition stage before the samples of the above examples and comparative examples. Each composition was applied onto the polyester film subjected to the release treatment, and the thickness after drying was 25 μm, and the gel fraction after one hour after coating was measured. The gel fraction was 0.2 g of the adhesive which was applied to the carrier at a temperature of 23 ° C and a humidity of 65% RH, and the fluororesin (TEMISH NTF-1122, manufactured by Nitto Denko Corporation) was used in advance. (W _a ) Wrap, bundle and not allow the adhesive to leak out, then measure its weight (W _b ) and place it in the vial. Ethyl acetate 40 cc was added and left for 7 days. Thereafter, the fluororesin was taken out, dried at 130 ° C for 2 hours on an aluminum cup, and the weight (W _c ) of the fluororesin including the sample was measured, and the gel fraction was determined by the following formula (I).

(W _c -W _a )/(W _b -W _a )×100 (% by weight)

<Processability, rapid crosslinkability>

After the sample was prepared, 100 pieces of a square having a length of 270 mm were punched out within 24 hours, and the operator observed by visual observation or hand touch to determine whether or not the side surface of the polarizing plate had a feeling of adhesion. Further, it is judged whether or not the surface of the polarizing plate is contaminated by the adhesive. A few samples were evaluated on the basis of the following criteria for adhesion and contamination.

○: 0 pieces out of 100 pieces.

△: 1 to 5 pieces out of 100 pieces.

×: 6 or more of 100 sheets.

<number of occurrences of marks>

The sample was cut into 350 mm × 250 mm, 20 sheets were laminated in the same direction in accordance with the manner in which the polarizing plate was placed thereon, and a hammer of 2 kg was placed on the polarizing plate of the uppermost layer, and left in this state at room temperature for one week. Thereafter, it is visually confirmed whether or not a depression and its number appear.

◎: 0

○: 1~3

×: 4 or more

<Durability>

The above sample was cut into 320 mm × 240 mm, and attached to an alkali-free glass (manufactured by Corning Co., Ltd., 1737) having a thickness of 0.7 mm, and treated with an autoclave at 50 ° C and 0.5 MPa for 15 minutes to prepare the above sample and the alkali-free glass. Completely closed. The sample subjected to the treatment was subjected to a treatment at 80 ° C, 90 ° C, 100 ° C, 60 ° C / 90% RH, 60 ° C / 95% RH for 500 hours, and then the foaming and peeling were visually evaluated on the following basis. The state of the uplift.

○: No foaming or peeling.

△: It was confirmed that there was foaming which did not affect the visibility (the maximum diameter was less than 100 μm).

×: It was confirmed that foaming (maximum diameter was 100 μm or more) and peeling were observed.

In Table 1, BA represents butyl acrylate, DMAEA represents N,N-dimethylaminoethyl acrylate, DMAPAA represents N,N-dimethylaminopropyl acrylamide, and ACMO represents N-propylene fluorenyl. Morpholine, AAM means acrylamide, AA means acrylic acid, 4HBA means 4-hydroxybutyl acrylate, 2HEA means 2-hydroxyethyl acrylate, and PEA means phenoxyethyl acrylate.

In Table 2, the isocyanate crosslinking agent is a polyol-modified hexamethylene diisocyanate (manufactured by Mitsui Takeda Polyurethane Co., Ltd., D160N), and a polyol-modified hydrogenated benzene dimethylene diisocyanate (Mitsui Takeda Polyurethane Co., Ltd.) Manufactured by the company, D120N), polyol modified isophorone diisocyanate (manufactured by Mitsui Takeda Polyurethane Co., Ltd., D140N), trimerized hydrogenated benzene dimethylene diisocyanate (manufactured by Mitsui Takeda Polyurethane Co., Ltd., D127N) Polyol-modified toluene diisocyanate (manufactured by Nippon Polyurethane Co., Ltd., C/L), polyol-modified xylene diisocyanate (manufactured by Mitsui Takeda Polyurethane Co., Ltd., D110N). The decane coupling agent is KBM573 or KBM403 manufactured by Shin-Etsu Chemical Co., Ltd. The *oligomer of the other additive of the comparative example 10 was 15 parts of the acrylic oligomer (weight average molecular weight 3000, manufactured by Toagosei Co., Ltd., ARFONUP-1000).

Claims (7)

An adhesive composition for an optical film, comprising: a (meth)acrylic polymer containing (a) an alkyl (meth)acrylate in an amount of 50 to 99.79 wt%, and (b) a tertiary amine 0.01 to 0.45 wt% of the base monomer and (c) 0.1 to 3% by weight of the hydroxyl group-containing monomer as a monomer unit, and having a weight average molecular weight of 1.8 to 3.5 million; and a crosslinking agent selected from the group consisting of hexamethylene Diisocyanate, hydrogenated benzene dimethylene diisocyanate, isophorone diisocyanate, polyol modified hexamethylene diisocyanate, polyol modified hydrogenated dimethylene diisocyanate, trimer hydrogenated benzodiazepine One of a group consisting of a methyl diisocyanate and a polyol-modified isophorone diisocyanate or a polyisocyanate compound derived therefrom, and containing 0.01% by weight based on 100 parts by weight of the (meth)acrylic polymer. 2 parts by weight of the crosslinking agent. The adhesive composition for an optical film according to claim 1, wherein the (meth)acrylic polymer further contains (d) a carboxyl group-containing monomer in an amount of 0.1 to 3% by weight. The adhesive composition for an optical film according to claim 1, wherein the (meth)acrylic polymer further contains 0.01 to 1 part by weight based on 100 parts by weight of the (meth)acrylic polymer. The adhesive composition for an optical film according to claim 3, wherein the decane coupling agent has an amine group. An adhesive layer for an optical film obtained by coating an adhesive composition for an optical film according to claim 1 and then subjecting it to a crosslinking reaction, and the gel fraction after coating for 1 hour It is 55~95%. An adhesive optical film characterized in that an adhesive layer for an optical film according to claim 5 is formed on at least one side of an optical member. An image display apparatus characterized by using at least one adhesive type optical film as claimed in claim 6.