JP5204612B2 - Adhesive composition for optical film, adhesive optical film, and image display device - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive composition for optical films that requires transparency and a pressure-sensitive adhesive optical film in which a pressure-sensitive adhesive layer is formed on at least one surface of the optical film. Furthermore, the present invention relates to an image display device such as a liquid crystal display device and an organic EL display device using the adhesive optical film. As the optical film, a polarizing plate, a phase difference plate, an optical compensation film, a brightness enhancement film, and a film in which these are laminated can be used.

  In a liquid crystal display or the like, it is indispensable to dispose polarizing elements on both sides of a liquid crystal cell because of its image forming method, and generally a polarizing plate is attached. In addition to polarizing plates, various optical elements have been used for liquid crystal panels in order to improve the display quality of displays. For example, a retardation plate for preventing coloring, a viewing angle widening film for improving the viewing angle of a liquid crystal display, and a brightness enhancement film for increasing the contrast of the display are used. These films are collectively called optical films.

  When an optical member such as the optical film is attached to a liquid crystal cell, an adhesive is usually used. In addition, the adhesion between the optical film and the liquid crystal cell, or the optical film is usually in close contact with each other using an adhesive in order to reduce the loss of light. In such a case, since the adhesive has the merit that a drying step is not required for fixing the optical film, the adhesive is an adhesive optical film provided in advance as an adhesive layer on one side of the optical film. Generally used.

  Necessary characteristics required for the pressure-sensitive adhesive include that when the optical film is bonded to the liquid crystal cell, the optical film is removed from the liquid crystal panel even when the bonding position is wrong or a foreign object is caught in the bonding surface. The liquid crystal cell may be reused by peeling off. In such a peeling step, re-peelability (reworkability) that can easily peel off the optical film from the liquid crystal panel without adhesive residue is required. In particular, in recent years, in addition to the conventional panel creation process, the use of thin liquid crystal panels using chemically etched glass has increased, making it difficult to rework and process optical films from the thin liquid crystal panels. ing. In addition, the pressure-sensitive adhesive is required to have a workability that can be processed without forming a stain or missing of the pressure-sensitive adhesive after the pressure-sensitive adhesive layer is formed on the optical film. Furthermore, the pressure-sensitive adhesive is required not to have a problem caused by the pressure-sensitive adhesive with respect to a durability test such as heating and humidification normally performed as an environmental promotion test.

  Conventionally, as a method for solving the problem of reworkability of a liquid crystal panel, it has been proposed that an acrylic polymer which is a base polymer of an acrylic pressure-sensitive adhesive contains a plasticizer or an oligomer component (Patent Document 1). However, this acrylic pressure-sensitive adhesive does not satisfy reworkability and workability with respect to the thin liquid crystal panel.

  In addition to the above, the acrylic pressure-sensitive adhesive used for the optical film includes, as a monomer component of the acrylic polymer, in addition to alkyl (meth) acrylate, a monomer having a hydroxyl group in the molecule, and a carboxyl group or amide in the molecule. In addition to alkyl (meth) acrylate, those containing monomers having functional groups such as groups and amino groups (Patent Documents 2 and 3), and monomer components of acrylic polymers, containing imide groups and amide groups A nitrogen-containing monomer such as a monomer and a peroxide and an isocyanate compound (Patent Document 4) have been proposed. However, the acrylic pressure-sensitive adhesives described in these patent documents all improve the durability, but do not sufficiently satisfy the reworkability and workability.

JP 2003-320837 A JP 2004-091499 A JP 2004-091500 A JP 2007-138147 A

  The present invention is a rework property that allows an optical film to be easily peeled off from a liquid crystal panel without adhesive residue, and a workability that can be processed without causing an adhesive layer to become dirty or missing after an adhesive layer is formed on the optical film. It is an object of the present invention to provide a pressure-sensitive adhesive composition for optical films capable of forming a pressure-sensitive adhesive layer that satisfies the above requirements and is less likely to cause dents.

  Another object of the present invention is to provide a pressure-sensitive adhesive optical film having a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition for optical films, and further to provide an image display device using the pressure-sensitive adhesive optical film. And

  As a result of intensive studies to solve the above problems, the present inventors have found the following pressure-sensitive adhesive composition for optical films and have completed the present invention.

That is, the present invention provides, as monomer units, (a) an alkyl (meth) acrylate 50 to 99.79% by weight, (b) a tertiary amino group-containing monomer 0.01 to 0.45% by weight, and (c) hydroxyl A (meth) acrylic polymer comprising 0.1 to 3% by weight of a group-containing monomer and having a weight average molecular weight of 1.5 million to 3.5 million;
As a crosslinking agent, one kind selected from the group consisting of hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, and isophorone diisocyanate or a polyisocyanate compound derived therefrom is used in an amount of 0 with respect to 100 parts by weight of the (meth) acrylic polymer. .01 to 2 parts by weight of an optical film pressure-sensitive adhesive composition.

  In the optical film pressure-sensitive adhesive composition, it is preferable that the (meth) acrylic polymer further contains (d) 0.1 to 3% by weight of a carboxyl group-containing monomer.

  In the said adhesive composition for optical films, it is preferable to contain 0.01-1 weight part of silane coupling agents further with respect to 100 weight part of (meth) acrylic-type polymers. The silane coupling agent preferably has an amino group.

  The present invention also provides an optical film pressure-sensitive adhesive obtained by coating one of the above pressure-sensitive adhesive compositions for an optical film and causing a crosslinking reaction, and having a gel fraction of 55 to 95% after 1 hour of coating. Agent layer.

  The present invention also relates to an adhesive optical film in which the above optical film pressure-sensitive adhesive layer is formed on at least one side of an optical member.

  The present invention also relates to an image display device using at least one adhesive optical film.

  The pressure-sensitive adhesive composition for an optical film of the present invention has a tertiary amino group-containing monomer as a base unit (meth) acrylic polymer in a small proportion of 0.01 to 0.45% by weight as a monomer unit. Contains. By adopting such a configuration, it is possible to improve the workability and reworkability of the optical member obtained from such a pressure-sensitive adhesive composition for optical films, and it is possible to suppress the loss and dirt of the pressure-sensitive adhesive during processing. Also, when the optical film is peeled off from a thin liquid crystal panel, particularly a liquid crystal panel using chemically etched glass, the peeling can be easily performed without adhesive residue. Moreover, it can peel from a liquid crystal panel, without breaking an optical film. As a result, the thin liquid crystal panel is not damaged, and the liquid crystal panel can be most effectively used.

  The tertiary amino group-containing monomer contained in the (meth) acrylic polymer in the above-mentioned small proportion has the crosslinking stability of the pressure-sensitive adhesive layer after the pressure-sensitive adhesive layer is formed by a crosslinking reaction with a crosslinking agent. It is thought that it is improving.

  Furthermore, the pressure-sensitive adhesive composition for an optical film of the present invention has improved durability and further improved reworkability by adding a hydroxyl group-containing monomer as a monomer unit to a (meth) acrylic polymer. .

  The pressure-sensitive adhesive composition of the present invention uses, as a crosslinking agent, one kind selected from the group consisting of hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, and isophorone diisocyanate or a polyisocyanate compound derived therefrom at the predetermined ratio. In this case, in particular, the immediate effect at the time of crosslinking can be improved by using a tertiary amino group-containing monomer. That is, the aging process after coating can be omitted. Moreover, as a crosslinking agent, a silane coupling agent can be further used in the predetermined range. In particular, when a silane coupling agent is used in combination with an isocyanate compound, the cross-linking stability is improved and reworkability and workability can be improved. Moreover, it is resistant to panel breakage and film breakage both during the manufacturing operation of the optical member having such an adhesive and during subsequent use.

  The pressure-sensitive adhesive composition for an optical film of the present invention comprises an alkyl (meth) acrylate 50 to 99.79% by weight, a tertiary amino group-containing monomer 0.01 to 0.45% by weight, and a hydroxyl group-containing monomer 0. A (meth) acrylic polymer containing 1 to 3% by weight is used as the base polymer. Furthermore, in the present invention, the base polymer (meth) acrylic polymer may optionally contain 0.1 to 3% by weight of a carboxyl group-containing monomer.

  As the alkyl (meth) acrylate, the alkyl group of the alkyl (meth) acrylate has about 2 to 18 carbon atoms. The alkyl group may be linear or branched. The alkyl group preferably has an average carbon number of 2 to 14, more preferably an average carbon number of 3 to 12, and further preferably an average carbon number of 4 to 9. (Meth) acrylate refers to acrylate and / or methacrylate, and (meth) of the present invention has the same meaning.

  Specific examples of the alkyl (meth) acrylate include ethyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, and n-pentyl. (Meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, isoamyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) Acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, isomyristyl (meth) acrylate n- tridecyl (meth) acrylate, n- tetradecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate. Especially, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, etc. can be illustrated and these can be used individually or in combination.

  In the present invention, the alkyl (meth) acrylate is 50 to 99.79% by weight, preferably 85 to 99.79% by weight, based on all monomer components of the (meth) acrylic polymer, Is more preferably 87 to 99.79% by weight, more preferably 90 to 99.79% by weight, and even more preferably 98 to 99.79% by weight. If the amount of the (meth) acrylic monomer is too small, the adhesiveness is poor, which is not preferable.

  Examples of the tertiary amino group-containing monomer include those containing a tertiary amino group and a (meth) acryloyl group. The tertiary amino group is preferably a tertiary aminoalkyl group. 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) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N- An example is diethylaminopropyl (meth) acrylamide.

  In addition, even if it is a nitrogen-containing monomer, monomers other than tertiary amino group-containing monomers, for example, maleimide monomers such as maleimide, N-cyclohexylmaleimide, N-phenylmaleimide; N- (meth) acryloyloxymethylene Succinimide monomers such as succinimide, N- (meth) acryloyl-6-oxyhexamethylene succinimide, N- (meth) acryloyl-8-oxyoctamethylene succinimide; (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-diethylmethacrylamide, N-isopropyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl N-substituted amide monomers such as (meth) acrylamide; monomers having secondary amino groups, such as t-butylaminoethyl (meth) acrylate, diacetone (meth) acrylamide, N-vinylacetamide, N, N ′ -Even if methylenebis (meth) acrylamide, N-vinylcaprolactam, N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, N-acryloylpyrrolidine, etc. are used alone, reworkability and processability are improved. It is difficult.

  The tertiary amino group-containing monomer is used in a proportion of 0.01 to 0.45% by weight based on the total amount of monomer components forming the (meth) acrylic polymer. The ratio of the tertiary amino group-containing monomer is preferably 0.01 to 0.40% by weight, more preferably 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 pressure-sensitive adhesive layer has poor crosslinking stability, cannot satisfy reworkability and processability, and is not preferable in terms of durability. On the other hand, from the viewpoint of reworkability, it is not preferable that the ratio of the tertiary amino group-containing monomer is too large, and the amount is controlled to 0.45% by weight or less.

  As the hydroxyl group-containing monomer, a monomer having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl 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, 4-hydroxybutyl (meth) acrylate, and 6-hydroxyhexyl ( Hydroxyalkyl (meth) acrylates such as (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate; hydroxyethyl (meth) acrylamide, and others (4 -Hydroxymethylcyclohexyl) methyl acrylate, N-methylol (meth) acrylamide, N-hydroxy (meth) acrylamide, allyl alcohol, 2-hydroxyethyl vinyl ether , 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether. Of these, hydroxyalkyl (meth) acrylate is preferred. In particular, 4-hydroxybutyl acrylate is preferable.

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

  As the carboxyl group-containing monomer, a monomer having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl 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. Of these, (meth) acrylic acid, particularly acrylic acid is preferred.

  When included, the carboxyl group-containing monomer is used in a proportion of 0.01 to 3% by weight based on the total amount of monomer components forming the (meth) acrylic polymer. The proportion of the carboxyl group-containing monomer is preferably 0.01 to 2% by weight, more preferably 0.01 to 0.7% by weight, and most preferably 0.05 to 0.5% by weight. . In order to improve durability, it is preferable to contain 0.01% by weight or more of a carboxyl group-containing monomer. On the other hand, if the proportion of the carboxyl group-containing monomer exceeds 3% by weight, the adhesive strength becomes strong, the peeling becomes heavy, and the rework property cannot be satisfied.

  As the monomer component forming the (meth) acrylic polymer, in addition to the monomer, a monomer other than the above may be used within a range of 45% by weight or less of the total amount of the monomer within the range not impairing the object of the present invention. it can. The ratio of the optional monomer is further preferably 40% by weight or less. Examples of such an optional monomer include an aromatic ring-containing monomer having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl 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, 2-naphthoethyl (meth) acrylate, 2-naphthoxyethyl acrylate, 2- (4-Methoxy-1-naphthoxy) ethyl (meth) acrylate, phenoxypropyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, thiol acrylate, pyridyl acrylate, pyrrole acrylate, phenyl acrylate, polystyryl (meth) acrylate, and the like. .

  Optional monomers other than the above include acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; caprolactone adducts of acrylic acid; styrene sulfonic acid and allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane Sulfonic acid group-containing monomers such as sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalene sulfonic acid; phosphoric acid group-containing monomers such as 2-hydroxyethylacryloyl phosphate; And (meth) acrylic acid alkoxyalkyl monomers such as methoxyethyl acrylate and ethoxyethyl (meth) acrylate.

  Furthermore, vinyl monomers such as vinyl acetate, vinyl propionate, styrene, α-methylstyrene, N-vinylcaprolactam; epoxy group-containing acrylic monomers such as glycidyl (meth) acrylate; polyethylene glycol (meth) acrylate, ( Glycol acrylic ester monomers such as (meth) acrylic acid polypropylene glycol, (meth) acrylic acid methoxyethylene glycol, (meth) acrylic acid methoxypolypropylene glycol; (meth) acrylic acid tetrahydrofurfuryl, fluorine (meth) acrylate, silicone (meta ) Acrylic acid ester monomers such as acrylate and 2-methoxyethyl acrylate can also be used.

  Furthermore, examples of copolymerizable monomers other than the above include silane monomers containing silicon atoms. Examples of the silane monomer include 3-acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, and 8-vinyloctyltrimethoxysilane. 8-vinyloctyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltriethoxysilane, 10-acryloyloxydecyltriethoxysilane, and the like.

  As the (meth) acrylic polymer of the present invention, those having a weight average molecular weight in the range of 1,500,000 to 3,500,000 are usually used. In view of durability, particularly heat resistance, it is preferable to use those having a weight average molecular weight of 1,500,000 to 3,000,000. Furthermore, it is more preferable that it is 1.7 million to 2.5 million, and it is further more preferable that it is 1.8 million to 2.5 million. A weight average molecular weight of less than 1,500,000 is not preferable in terms of heat resistance. Moreover, when a weight average molecular weight becomes larger than 3.5 million, it is not preferable also in the point that bonding property and adhesive force fall. The weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene.

  The production of such a (meth) acrylic polymer can be appropriately selected from known production methods such as solution polymerization, bulk polymerization, emulsion polymerization, and various radical polymerizations. Further, the (meth) acrylic polymer obtained may be any of a random copolymer, a block copolymer, a graft copolymer, and the like.

  In solution polymerization, for example, ethyl acetate, toluene or the like is used as a polymerization solvent. As a specific example of solution polymerization, the reaction is performed under an inert gas stream such as nitrogen, and a polymerization initiator is added, and the reaction is usually performed at about 50 to 70 ° C. under reaction conditions of about 5 to 30 hours.

  The polymerization initiator, chain transfer agent, emulsifier and the like used for radical polymerization are not particularly limited and can be appropriately selected and used. In addition, the weight average molecular weight of a (meth) acrylic-type polymer can be controlled by the usage-amount of a polymerization initiator and a chain transfer agent, and reaction conditions, The usage-amount is suitably adjusted according to these kinds.

  Examples of the polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis [2- (5-methyl-2). -Imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis (2-methylpropionamidine) disulfate, 2,2'-azobis (N, N'-dimethyleneisobutylamidine), 2,2 '-Azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate (manufactured by Wako Pure Chemical Industries, VA-057) and other azo initiators, and persulfates such as potassium persulfate and ammonium persulfate , Di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butyl -Oxydicarbonate, t-butylperoxyneodecanoate, t-hexylperoxypivalate, t-butylperoxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3 , 3-tetramethylbutylperoxy-2-ethylhexanoate, di (4-methylbenzoyl) peroxide, dibenzoyl peroxide, t-butylperoxyisobutyrate, 1,1-di (t-hexylperoxy) ) Peroxides such as cyclohexane, t-butyl hydroperoxide, hydrogen peroxide, peroxides and sodium bisulfite, peroxides and sodium ascorbate Redox initiators combined with Not intended to be.

  The polymerization initiator may be used alone or in combination of two or more, but the total content is 0.005 to 1 part by weight with respect to 100 parts by weight of the monomer. Is preferably about 0.02 to 0.5 parts by weight.

  In order to produce the (meth) acrylic polymer having the weight average molecular weight using, for example, 2,2′-azobisisobutyronitrile as the polymerization initiator, the amount of the polymerization initiator used is a monomer. The amount is preferably about 0.06 to 0.2 part by weight, more preferably about 0.08 to 0.175 part by weight with respect to 100 parts by weight of the total amount of the components.

  Examples of the chain transfer agent include lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, and 2,3-dimercapto-1-propanol. The chain transfer agent may be used alone or in combination of two or more, but the total content is 0.1 parts by weight with respect to 100 parts by weight of the total amount of monomer components. Less than or equal to

  Examples of the emulsifier used in emulsion polymerization include anionic emulsifiers such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, ammonium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, and polyoxy Nonionic emulsifiers such as ethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, and polyoxyethylene-polyoxypropylene block polymer are listed. These emulsifiers may be used alone or in combination of two or more.

  Further, as reactive emulsifiers, as emulsifiers into which radical polymerizable functional groups such as propenyl groups and allyl ether groups are introduced, specifically, for example, Aqualon HS-10, HS-20, KH-10, BC-05 BC-10, BC-20 (all of which are manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Adekaria Soap SE10N (Asahi Denka Kogyo Co., Ltd.), and the like. Reactive emulsifiers are preferable because they are incorporated into the polymer chain after polymerization and thus have improved water resistance. The amount of the emulsifier used is more preferably 0.3 to 5 parts by weight and 0.5 to 1 part by weight from the viewpoint of polymerization stability and mechanical stability with respect to 100 parts by weight of the total amount of monomer components.

  The pressure-sensitive adhesive composition of the present invention contains a polyisocyanate compound as a crosslinking agent. This polyisocyanate compound is one selected from the group consisting of hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, and isophorone diisocyanate, or a polyisocyanate compound derived therefrom. Here, hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, polyol-modified is selected from the group consisting of hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, and isophorone diisocyanate or a polyisocyanate compound derived therefrom. Examples include hexamethylene diisocyanate, polyol-modified hydrogenated xylylene diisocyanate, trimer-type hydrogenated xylylene diisocyanate, and polyol-modified isophorone diisocyanate. The exemplified polyisocyanate compound is preferable because the reaction with a hydroxyl group proceeds rapidly, particularly using an acid or base contained in the polymer as a catalyst, and thus contributes to the speed of crosslinking.

  The isocyanate-based crosslinking agent may be used alone or in combination of two or more, but the total content is 100 parts by weight of the (meth) acrylic polymer. On the other hand, the polyisocyanate compound crosslinking agent is preferably contained in an amount of 0.01 to 2 parts by weight, more preferably 0.04 to 1.5 parts by weight, and 0.05 to 1 part by weight is contained. More preferably, If it is less than 0.01 part by weight, the cohesive force may be insufficient, which is not preferable. On the other hand, if it exceeds 2 parts by weight, it is not preferred because peeling tends to occur in the durability test.

  In the pressure-sensitive adhesive composition of the present invention, a silane coupling agent can be used for the purpose of increasing adhesive strength and durability. As the silane coupling agent, known ones can be appropriately used without particular limitation.

  Specifically, for example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltri Epoxy group-containing silane coupling agents such as methoxysilane, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1,3- (Meth) such as dimethylbutylidene) propylamine, amino group-containing silane coupling agents such as N-phenyl-γ-aminopropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, etc. Acrylic group-containing silane coupling And isocyanate group-containing silane coupling agents such as 3-isocyanate propyl triethoxysilane and the like. Among them, it is preferable to use an amino group-containing silane coupling agent because it leads to improvement in durability and reworkability during humidification, but there is no limitation, and other silane coupling agents also improve durability. This is preferable.

  The silane coupling agent may be used alone or in combination of two or more, but the total content is 100 parts by weight of the (meth) acrylic polymer. It is preferable to contain 0.01-2 weight part of silane coupling agents, it is more preferable to contain 0.02-0.6 weight part, and 0.05-0.3 weight part is contained. More preferably. It is an amount that improves durability and appropriately maintains the adhesive force to an optical member such as a liquid crystal cell.

  Furthermore, in the present invention, it is possible to optionally contain a peroxide as another crosslinking agent.

  As the peroxide of the present invention, any radical active species can be used as long as it generates radical active species by heating or light irradiation to advance the crosslinking of the base polymer of the pressure-sensitive adhesive composition. However, the workability and stability are improved. Considering this, it is preferable to use a peroxide having a half-life temperature of 80 ° C. to 160 ° C., more preferably a peroxide having a half-life temperature of 90 ° C. to 140 ° C.

  Examples of peroxides that can be used include di (2-ethylhexyl) peroxydicarbonate (1 minute half-life temperature: 90.6 ° C.), di (4-t-butylcyclohexyl) peroxydicarbonate (1 Minute half-life temperature: 92.1 ° C.), di-sec-butyl peroxydicarbonate (1 minute half-life temperature: 92.4 ° C.), t-butyl peroxyneodecanoate (1 minute half-life temperature: 103 0.5 ° C), t-hexyl peroxypivalate (1 minute half-life temperature: 109.1 ° C), t-butyl peroxypivalate (1 minute half-life temperature: 110.3 ° C), dilauroyl peroxide ( 1 minute half-life temperature: 116.4 ° C.), di-n-octanoyl peroxide (1 minute half-life temperature: 117.4 ° C.), 1,1,3,3-tetramethylbutyl Oxy-2-ethylhexanoate (1 minute half-life temperature: 124.3 ° C), di (4-methylbenzoyl) peroxide (1 minute half-life temperature: 128.2 ° C), dibenzoyl peroxide (half-minute for 1 minute) Period temperature: 130.0 ° C.), t-butyl peroxyisobutyrate (1 minute half-life temperature: 136.1 ° C.), 1,1-di (t-hexylperoxy) cyclohexane (1 minute half-life temperature: 149.2 ° C.). Especially, since the crosslinking reaction efficiency is excellent, di (4-t-butylcyclohexyl) peroxydicarbonate (1 minute half-life temperature: 92.1 ° C.), dilauroyl peroxide (1 minute half-life temperature: 116. 4 ° C), dibenzoyl peroxide (1 minute half-life temperature: 130.0 ° C) and the like are preferably used.

  The peroxide half-life is an index representing the decomposition rate of the peroxide, and means the time until the remaining amount of peroxide is reduced to half. The decomposition temperature for obtaining a half-life at an arbitrary time and the half-life time at an arbitrary temperature are described in the manufacturer catalog, for example, “Organic peroxide catalog 9th edition by Nippon Oil & Fats Co., Ltd.” (May 2003) ".

  The peroxide may be used alone or as a mixture of two or more, but the total content is based on 100 parts by weight of the (meth) acrylic polymer. The peroxide is 0.01 to 2 parts by weight, preferably 0.04 to 1.5 parts by weight, and more preferably 0.05 to 1 part by weight. It is appropriately selected for adjustment of processability, reworkability, cross-linking stability, peelability and the like.

  In addition, as a measuring method of the peroxide decomposition amount which remained after the reaction process, it can measure by HPLC (high performance liquid chromatography), for example.

  More specifically, for example, about 0.2 g of the pressure-sensitive adhesive composition after the reaction treatment is taken out, immersed in 10 ml of ethyl acetate, extracted by shaking at 25 ° C. and 120 rpm for 3 hours with a shaker, and then at room temperature. Leave for 3 days. Next, 10 ml of acetonitrile was added, shaken at 120 rpm at 25 ° C. for 30 minutes, and about 10 μl of the extract obtained by filtration through a membrane filter (0.45 μm) was injected into the HPLC for analysis. The amount of peroxide can be set.

  Furthermore, as said crosslinking agent, another organic type crosslinking agent and polyfunctional metal chelate can be used. Examples of the organic crosslinking agent include an epoxy crosslinking agent and an imine crosslinking agent. A polyfunctional metal chelate is one in which a polyvalent metal is covalently or coordinately bonded to an organic compound. Examples of polyvalent metal atoms 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. can give. Examples of the atom in the organic compound that is covalently or coordinately bonded include an oxygen atom, and the organic compound includes an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound, a ketone compound, and the like.

  The pressure-sensitive adhesive layer is formed by the crosslinking agent. In forming the pressure-sensitive adhesive layer, it is necessary to adjust the addition amount of the entire crosslinking agent and sufficiently consider the influence of the crosslinking treatment temperature and the crosslinking treatment time.

  The crosslinking treatment temperature and the crosslinking treatment time can be adjusted depending on the crosslinking agent used. The crosslinking treatment temperature is preferably 170 ° C. or lower.

  Moreover, this crosslinking process may be performed at the temperature at the time of the drying process of an adhesive layer, and may be performed by providing a crosslinking process process separately after a drying process.

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

  Furthermore, the pressure-sensitive adhesive composition of the present invention may contain other known additives, such as powders such as colorants and pigments, dyes, surfactants, plasticizers, tackifiers, Use surface lubricants, leveling agents, softeners, antioxidants, anti-aging agents, light stabilizers, UV absorbers, polymerization inhibitors, inorganic or organic fillers, metal powders, particles, foils, etc. It can be added appropriately depending on the application. Moreover, you may employ | adopt the redox system which added a reducing agent within the controllable range.

  The pressure-sensitive adhesive optical member such as the pressure-sensitive adhesive optical film of the present invention has a pressure-sensitive adhesive layer formed on at least one surface of the optical film with the pressure-sensitive adhesive.

  As a method for forming the pressure-sensitive adhesive layer, for example, a method in which the pressure-sensitive adhesive composition is applied to a release-treated separator, and the polymerization solvent is dried and removed to form a pressure-sensitive adhesive layer, and then transferred to an optical film, or The pressure-sensitive adhesive composition is prepared by applying the pressure-sensitive adhesive composition to an optical film, drying and removing a polymerization solvent, and the like to form a pressure-sensitive adhesive layer on the optical film. In applying the pressure-sensitive adhesive, one or more solvents other than the polymerization solvent may be added as appropriate.

  Moreover, an adhesive layer can be formed after forming an anchor layer on the surface of an optical film, or performing various easy-adhesion treatments, such as a corona treatment and a plasma treatment. Moreover, you may perform an easily bonding process on the surface of an adhesive layer.

  Various methods are used as a method of forming the pressure-sensitive adhesive layer. Specifically, for example, roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, die coater, etc. Examples thereof include an extrusion coating method.

  The thickness in particular of an adhesive layer is not restrict | limited, For example, it is about 1-100 micrometers. Preferably, it is 5-50 micrometers, More preferably, it is 10-30 micrometers.

  The gel fraction after 1 hour of application of the pressure-sensitive adhesive layer of the present invention thus obtained is 55% to 95%, preferably 60 to 95%, more preferably 70 to 95. %. Such a gel fraction means that the crosslinking speed is high, the occurrence of dents is small, and no dent is generated in the obtained pressure-sensitive adhesive layer.

  When the pressure-sensitive adhesive layer is exposed, the pressure-sensitive adhesive layer may be protected with a sheet (separator) that has been subjected to a release treatment until practical use.

  Examples of the constituent material of the separator include, for example, plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films, porous materials such as paper, cloth, and nonwoven fabric, nets, foam sheets, metal foils, and laminates thereof. A thin film can be used, but a plastic film is preferably used because of its excellent surface smoothness.

  The plastic film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer. For example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, and a vinyl chloride co-polymer are used. Examples thereof include a polymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

  The thickness of the separator is usually about 5 to 200 μm, preferably about 5 to 100 μm. For the separator, if necessary, mold release and antifouling treatment with a silicone type, fluorine type, long chain alkyl type or fatty acid amide type release agent, silica powder, etc., coating type, kneading type, vapor deposition type It is also possible to carry out antistatic treatment such as. In particular, when the surface of the separator is appropriately subjected to a release treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment, the peelability from the pressure-sensitive adhesive layer can be further improved.

  In addition, the sheet | seat which carried out the peeling process used in preparation of said adhesive type optical film can be used as a separator of an adhesive type optical film as it is, and can simplify in the surface of a process.

  As an optical film, what is used for formation of image display apparatuses, such as a liquid crystal display device, is used, and the kind in particular is not restrict | limited. For example, the optical film includes a polarizing plate. A polarizing plate having a transparent protective film on one or both sides of a polarizer is generally used.

  The polarizer is not particularly limited, and various types can be used. Examples of polarizers include dichroic iodine and dichroic dyes on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films. Examples thereof include polyene-based oriented films such as those obtained by adsorbing substances and uniaxially stretched, polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products. Among these, a polarizer composed of a polyvinyl alcohol film and a dichroic material such as iodine is preferable. The thickness of these polarizers is not particularly limited, but is generally about 5 to 80 μm.

  A polarizer obtained by dyeing a polyvinyl alcohol film with iodine and uniaxially stretching it can be prepared, for example, by immersing polyvinyl alcohol in an aqueous solution of iodine and stretching it 3 to 7 times the original length. If necessary, it can be immersed in an aqueous solution such as potassium iodide which may contain boric acid, zinc sulfate, zinc chloride or the like. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. In addition to washing the polyvinyl alcohol film surface with dirt and anti-blocking agents by washing the polyvinyl alcohol film with water, it also has the effect of preventing unevenness such as uneven coloring by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. The film can be stretched even in an aqueous solution such as boric acid or potassium iodide or in a water bath.

  Examples of the optical film used in the pressure-sensitive adhesive optical film of the present invention include a polarizing plate. A polarizing plate having a transparent protective film on one or both sides of a polarizer is generally used.

  The polarizer is not particularly limited, and various types can be used. Examples of polarizers include dichroic iodine and dichroic dyes on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films. Examples thereof include polyene-based oriented films such as those obtained by adsorbing substances and uniaxially stretched, polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products. Among these, a polarizer composed of a polyvinyl alcohol film and a dichroic material such as iodine is preferable. The thickness of these polarizers is not particularly limited, but is generally about 5 to 80 μm.

  A polarizer obtained by dyeing a polyvinyl alcohol film with iodine and uniaxially stretching it can be prepared, for example, by immersing polyvinyl alcohol in an aqueous solution of iodine and stretching it 3 to 7 times the original length. If necessary, it can be immersed in an aqueous solution such as potassium iodide which may contain boric acid, zinc sulfate, zinc chloride or the like. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. In addition to washing the polyvinyl alcohol film surface with dirt and anti-blocking agents by washing the polyvinyl alcohol film with water, it also has the effect of preventing unevenness such as uneven coloring by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. The film can be stretched even in an aqueous solution such as boric acid or potassium iodide or in a water bath.

  As a material constituting the transparent protective film, for example, a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like is used. Specific examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth) acrylic resins, cyclic Examples thereof include polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. A transparent protective film is bonded to one side of the polarizer by an adhesive layer. On the other side, as a transparent protective film, (meth) acrylic, urethane-based, acrylurethane-based, epoxy-based, silicone A thermosetting resin such as a system or an ultraviolet curable resin can be used. One or more kinds of arbitrary appropriate additives may be contained in the transparent protective film. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, a coloring inhibitor, a flame retardant, a nucleating agent, an antistatic agent, a pigment, and a coloring agent. The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. . When content of the said thermoplastic resin in a transparent protective film is 50 weight% or less, there exists a possibility that the high transparency etc. which a thermoplastic resin originally has cannot fully be expressed.

  Moreover, as a transparent protective film, the polymer film as described in Unexamined-Japanese-Patent No. 2001-343529 (WO01 / 37007), for example, (A) thermoplastic resin which has a substituted and / or unsubstituted imide group in a side chain, ( B) Resin compositions containing thermoplastic resins having substituted and / or unsubstituted phenyl and nitrile groups in the side chains. A specific example is a film of a resin composition containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer. As the film, a film made of a mixed extruded product of the resin composition or the like can be used. Since these films have a small phase difference and a small photoelastic coefficient, problems such as unevenness due to the distortion of the polarizing plate can be eliminated, and since the moisture permeability is small, the humidification durability is excellent.

  Although the thickness of a transparent protective film can be determined suitably, generally it is about 1-500 micrometers from points, such as workability | operativity, such as intensity | strength and handleability, and thin layer property. 1-300 micrometers is especially preferable, and 5-200 micrometers is more preferable. The transparent protective film is particularly suitable when the thickness is 5 to 150 μm.

  In addition, when providing a transparent protective film on both sides of a polarizer, the protective film which consists of the same polymer material may be used by the front and back, and the protective film which consists of a different polymer material etc. may be used.

  As the transparent protective film of the present invention, it is preferable to use at least one selected from cellulose resin, polycarbonate resin, cyclic polyolefin resin, and (meth) acrylic resin.

  Cellulose resin is an ester of cellulose and fatty acid. Specific examples of the cellulose ester resin include triacetyl cellulose, diacetyl cellulose, tripropionyl cellulose, dipropionyl cellulose and the like. Among these, triacetyl cellulose is particularly preferable. Many products of triacetylcellulose are commercially available, which is advantageous in terms of availability and cost. Examples of commercially available products of triacetyl cellulose include trade names “UV-50”, “UV-80”, “SH-80”, “TD-80U”, “TD-TAC”, and “UZ” manufactured by Fujifilm Corporation. -TAC "and" KC series "manufactured by Konica. In general, these triacetyl celluloses have an in-plane retardation (Re) of almost zero, but a thickness direction retardation (Rth) of about 60 nm.

  In addition, the cellulose resin film with a small thickness direction phase difference is obtained by processing the said cellulose resin, for example. For example, a base film such as polyethylene terephthalate, polypropylene, and stainless steel coated with a solvent such as cyclopentanone and methyl ethyl ketone is bonded to a general cellulose film and dried by heating (for example, at 80 to 150 ° C. for about 3 to 10 minutes). ) And then peeling the base film; a solution obtained by dissolving norbornene resin, (meth) acrylic resin, etc. in a solvent such as cyclopentanone, methyl ethyl ketone, etc. is applied to a general cellulose resin film and dried by heating ( For example, a method of peeling the coated film after 80 to 150 ° C. for about 3 to 10 minutes is mentioned.

  Moreover, as a cellulose resin film with a small thickness direction retardation, the fatty acid cellulose resin film which controlled the fat substitution degree can be used. Generally used triacetyl cellulose has an acetic acid substitution degree of about 2.8. Preferably, the Rth can be reduced by controlling the acetic acid substitution degree to 1.8 to 2.7. Rth can be controlled to be small by adding a plasticizer such as dibutyl phthalate, p-toluenesulfonanilide, acetyltriethyl citrate to the fatty acid-substituted cellulose resin. The addition amount of the plasticizer is preferably 40 parts by weight or less, more preferably 1 to 20 parts by weight, and still more preferably 1 to 15 parts by weight with respect to 100 parts by weight of the fatty acid cellulose resin.

  Specific examples of the cyclic polyolefin resin are preferably norbornene resins. The cyclic olefin-based resin is a general term for resins that are polymerized using a cyclic olefin as a polymerization unit, and is described in, for example, JP-A-1-240517, JP-A-3-14882, JP-A-3-122137, and the like. Resin. Specific examples include ring-opening (co) polymers of cyclic olefins, addition polymers of cyclic olefins, cyclic olefins and α-olefins such as ethylene and propylene (typically random copolymers), And graft polymers obtained by modifying them with an unsaturated carboxylic acid or a derivative thereof, and hydrides thereof. Specific examples of the cyclic olefin include norbornene monomers.

  Various products are commercially available as the cyclic polyolefin resin. As specific examples, trade names “ZEONEX” and “ZEONOR” manufactured by ZEON CORPORATION, product names “ARTON” manufactured by JSR Corporation, “TOPAS” manufactured by TICONA, and product names manufactured by Mitsui Chemicals, Inc. “APEL”.

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

  As the (meth) acrylic resin, any appropriate (meth) acrylic resin can be adopted as long as the effects of the present invention are not impaired. For example, poly (meth) acrylic acid ester such as polymethyl methacrylate, methyl methacrylate- (meth) acrylic acid copolymer, methyl methacrylate- (meth) acrylic acid ester copolymer, methyl methacrylate-acrylic acid ester- (Meth) acrylic acid copolymer, (meth) methyl acrylate-styrene copolymer (MS resin, etc.), polymer having an alicyclic hydrocarbon group (for example, methyl methacrylate-cyclohexyl methacrylate copolymer, Methyl methacrylate- (meth) acrylate norbornyl copolymer, etc.). Preferably, poly (meth) acrylate C1-6 alkyl such as poly (meth) acrylate methyl is used. More preferred is a methyl methacrylate resin containing methyl methacrylate as a main component (50 to 100% by weight, preferably 70 to 100% by weight).

  Specific examples of (meth) acrylic resins include (meth) acrylic resins having a ring structure in the molecule described in, for example, Acrypet VH and Acrypet VRL20A manufactured by Mitsubishi Rayon Co., Ltd., and JP-A-2004-70296. And a high Tg (meth) acrylic resin system obtained by intramolecular crosslinking or intramolecular cyclization reaction.

  As the (meth) acrylic resin, a (meth) acrylic resin having a lactone ring structure can also be used. It is because it has high mechanical strength by high heat resistance, high transparency, and biaxial stretching.

  Examples of the (meth) acrylic resin having a lactone ring structure include JP 2000-230016, JP 2001-151814, JP 2002-120326, JP 2002-254544, and JP 2005. Examples thereof include (meth) acrylic resins having a lactone ring structure described in Japanese Patent No. 146084.

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

^Wherein, R 1, ^{R 2} and ^{R 3} each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms. The organic residue may contain an oxygen atom.

  The content ratio of the lactone ring structure represented by the general formula (Formula 1) in the structure of the (meth) acrylic resin having a lactone ring structure is preferably 5 to 90% by weight, more preferably 10 to 70% by weight, More preferably, it is 10 to 60% by weight, and particularly preferably 10 to 50% by weight. When the content of the lactone ring structure represented by the general formula (Chemical Formula 1) in the structure of the (meth) acrylic resin having a lactone ring structure is less than 5% by weight, the heat resistance, solvent resistance, and surface hardness are low. May be insufficient. If the content of the lactone ring structure represented by the general formula (Chemical Formula 1) in the structure of the (meth) acrylic resin having a lactone ring structure is more than 90% by weight, molding processability may be poor.

  The (meth) acrylic resin having a lactone ring structure has a mass average molecular weight (sometimes referred to as a weight average molecular weight) of preferably 1,000 to 2,000,000, more preferably 5,000 to 1,000,000, still more preferably 10,000 to 500,000, and particularly preferably. Is 50,000 to 500,000. If the mass average molecular weight is out of the above range, it is not preferable from the viewpoint of molding processability.

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

  The (meth) acrylic resin having a lactone ring structure is preferably as the total light transmittance of a molded product obtained by injection molding measured by a method according to ASTM-D-1003 is higher, preferably 85. % Or more, more preferably 88% or more, and still more preferably 90% or more. The total light transmittance is a measure of transparency. If the total light transmittance is less than 85%, the transparency may be lowered.

  As the transparent protective film, one having a front phase difference of less than 40 nm and a thickness direction retardation of less than 80 nm is usually used. The front phase difference Re is represented by Re = (nx−ny) × d. The thickness direction retardation Rth is represented by Rth = (nx−nz) × d. The Nz coefficient is represented by Nz = (nx−nz) / (nx−ny). [However, the refractive indexes in the slow axis direction, the fast axis direction, and the thickness direction of the film are nx, ny, and nz, respectively, and d (nm) is the thickness of the film. The slow axis direction is the direction that maximizes the refractive index in the film plane. ]. In addition, it is preferable that a transparent protective film has as little color as possible. A protective film having a thickness direction retardation value of −90 nm to +75 nm is preferably used. By using a film having a thickness direction retardation value (Rth) of −90 nm to +75 nm, the coloring (optical coloring) of the polarizing plate caused by the transparent protective film can be almost eliminated. The thickness direction retardation value (Rth) is more preferably −80 nm to +60 nm, and particularly preferably −70 nm to +45 nm.

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

  Examples of the retardation plate include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, a liquid crystal polymer alignment film, and a liquid crystal polymer alignment layer supported by a film. The thickness of the retardation plate is not particularly limited, but is generally 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, polycarbonate, polyarylate, polysulfone, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, Polyphenylene sulfide, polyphenylene oxide, polyallylsulfone, polyamide, polyimide, polyolefin, polyvinyl chloride, cellulose resin, cyclic polyolefin resin (norbornene resin), or any of these binary, ternary copolymers, graft copolymers Examples thereof include polymers and blends. These polymer materials become an oriented product (stretched film) by stretching or the like.

  Examples of the liquid crystal polymer include various main chain types and side chain types in which a conjugated linear atomic group (mesogen) imparting liquid crystal alignment is introduced into the main chain or side chain of the polymer. . Specific examples of the main chain type liquid crystal polymer include a nematic alignment polyester liquid crystal polymer, a discotic polymer, and a cholesteric polymer having a structure in which a mesogen group is bonded at a spacer portion that imparts flexibility. Specific examples of the side chain type liquid crystal polymer include polysiloxane, polyacrylate, polymethacrylate, or polymalonate as a main chain skeleton, and a nematic alignment-providing para-substitution through a spacer portion composed of a conjugated atomic group as a side chain. Examples thereof include those having a mesogenic part composed of a cyclic compound unit. These liquid crystal polymers can be prepared by, for example, applying a solution of a liquid crystalline polymer on an alignment surface such as a surface of a thin film such as polyimide or polyvinyl alcohol formed on a glass plate, or an oblique deposition of silicon oxide. This is done by developing and heat treatment.

  The retardation plate may have an appropriate retardation according to the purpose of use, such as those for the purpose of compensating for various wavelength plates or birefringence of liquid crystal layers and compensation of viewing angle, etc. It may be one in which retardation plates are stacked and optical characteristics such as retardation are controlled.

  The retardation plate has a relationship of nx = ny> nz, nx> ny> nz, nx> ny = nz, nx> nz> ny, nz = nx> ny, nz> nx> ny, nz> nx = ny. What is satisfactory is selected and used according to various applications. Note that ny = nz includes 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, in a phase difference plate that satisfies nx> ny> nz, a surface plate having a front phase difference of 40 to 100 nm, a thickness direction phase difference of 100 to 320 nm, and an Nz coefficient of 1.8 to 4.5 is used. Is preferred. For example, in a retardation plate (positive A plate) that satisfies nx> ny = nz, it is preferable to use a retardation plate that satisfies a front phase difference of 100 to 200 nm. For example, for a retardation plate (negative A plate) that satisfies nz = nx> ny, it is preferable to use a retardation plate that satisfies a front phase difference of 100 to 200 nm. For example, in a retardation plate satisfying nx> nz> ny, it is preferable to use a retardation plate having a front phase difference of 150 to 300 nm and an Nz coefficient exceeding 0 to 0.7. As described above, for example, a material satisfying nx = ny> nz, nz> nx> ny, or nz> nx = ny can be used.

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

  For example, in the case of IPS (including In-Plane Switching, FFS), both cases where the transparent protective film on one side of the polarizing plate has a phase difference and does not have a phase difference can be used. For example, when there is no phase difference, it is desirable that the liquid crystal cell does not have a phase difference both above and below (cell side). In the case where the liquid crystal cell has a phase difference, it is desirable that the liquid crystal cell has a phase difference in the upper and lower sides, or the upper and lower sides have a phase difference (for example, nx> nz> ny on the upper side). Biaxial film satisfying the relationship, when there is no retardation on the lower side, positive A plate on the upper side, and positive C plate on the lower side). When it has a phase difference, it is desirable that Re = −500 to 500 nm and Rth = −500 to 500 nm. 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 desirable.

  In addition, the film which has the said phase difference can be separately bonded to the transparent protective film which does not have a phase difference, and the said function can be provided.

  The transparent protective film may be subjected to surface modification treatment in order to improve adhesiveness with the polarizer before applying the adhesive. Specific examples of the treatment include corona treatment, plasma treatment, flame treatment, ozone treatment, primer treatment, glow treatment, saponification treatment, and treatment with a coupling agent. Further, an antistatic layer can be appropriately formed.

  The surface of the transparent protective film to which the polarizer is not adhered may be subjected to a hard coat layer, an antireflection treatment, an antisticking treatment, or a treatment for diffusion or antiglare.

  The hard coat treatment is applied for the purpose of preventing scratches on the surface of the polarizing plate. For example, a transparent protective film with a cured film excellent in hardness, sliding properties, etc. by an appropriate ultraviolet curable resin such as acrylic or silicone is used. It can be formed by a method of adding to the surface of the film. The antireflection treatment is performed for the purpose of preventing reflection of external light on the surface of the polarizing plate, and can be achieved by forming an antireflection film or the like according to the conventional art. In addition, the sticking prevention treatment is performed for the purpose of preventing adhesion with an adjacent layer (for example, a backlight-side diffusion plate).

  The anti-glare treatment is applied for the purpose of preventing the outside light from being reflected on the surface of the polarizing plate and obstructing the visibility of the light transmitted through the polarizing plate. For example, the surface is roughened by a sandblasting method or an embossing method. It can be formed by imparting a fine concavo-convex structure to the surface of the transparent protective film by an appropriate method such as a blending method of transparent fine particles. Examples of the fine particles to be included in the formation of the surface fine concavo-convex structure include conductive materials made of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, and the like having an average particle diameter of 0.5 to 20 μm. In some cases, transparent fine particles such as inorganic fine particles, organic fine particles composed of a crosslinked or uncrosslinked polymer, and the like are used. When forming the surface fine uneven structure, the amount of fine particles used is generally about 2 to 70 parts by weight, preferably 5 to 50 parts by weight, based on 100 parts by weight of the transparent resin forming the surface fine uneven structure. The antiglare layer may also serve as a diffusion layer (viewing angle expanding function or the like) for diffusing the light transmitted through the polarizing plate to expand the viewing angle.

  The antireflection layer, antisticking layer, diffusion layer, antiglare layer, and the like can be provided on the transparent protective film itself, or can be provided separately from the transparent protective film as an optical layer.

  An adhesive is used for the adhesion treatment between the polarizer and the transparent protective film. Examples of the adhesive include isocyanate adhesives, polyvinyl alcohol adhesives, gelatin adhesives, vinyl latexes, and water-based polyesters. The said adhesive agent is normally used as an adhesive agent which consists of aqueous solution, and contains 0.5 to 60 weight% of solid content normally. In addition to the above, examples of the adhesive between the polarizer and the transparent protective film include an ultraviolet curable adhesive and an electron beam curable adhesive. The electron beam curable polarizing plate adhesive exhibits suitable adhesion to the various transparent protective films. The adhesive used in the present invention can contain a metal compound filler.

  In addition, as an optical film, for example, for formation of a liquid crystal display device such as a reflection plate, an anti-transmission plate, the retardation plate (including wavelength plates such as 1/2 and 1/4), a visual compensation film, and a brightness enhancement film. The optical layer which may be used is mentioned. These can be used alone as an optical film, or can be laminated on the polarizing plate for practical use and used as one layer or two or more layers.

  In particular, a reflective polarizing plate or a semi-transmissive polarizing plate in which a polarizing plate is further laminated with a reflecting plate or a semi-transmissive reflecting plate, an elliptical polarizing plate or a circular polarizing plate in which a retardation plate is further laminated on a polarizing plate, a polarizing plate A wide viewing angle polarizing plate in which a visual compensation film is further laminated on a plate, or a polarizing plate in which a luminance enhancement film is further laminated on a polarizing plate is preferable.

  A reflective polarizing plate is a polarizing plate provided with a reflective layer, and is used to form a liquid crystal display device or the like that reflects incident light from the viewing side (display side). Such a light source can be omitted, and the liquid crystal display device can be easily thinned. The reflective polarizing plate can be formed by an appropriate method such as a method in which a reflective layer made of metal or the like is attached to one surface of the polarizing plate via a transparent protective layer or the like as necessary.

  Specific examples of the reflective polarizing plate include those in which a reflective layer is formed by attaching a foil or a vapor deposition film made of a reflective metal such as aluminum on one side of a transparent protective film matted as necessary. In addition, the transparent protective film may contain fine particles to form a surface fine concavo-convex structure, and a reflective layer having a fine concavo-convex structure thereon. The reflective layer having the fine concavo-convex structure has an advantage that incident light is diffused by irregular reflection to prevent directivity and glaring appearance and to suppress unevenness in brightness and darkness. Moreover, the protective film containing fine particles also has an advantage that incident light and its reflected light are diffused when passing through it and light and dark unevenness can be further suppressed. The reflective layer of the fine concavo-convex structure reflecting the surface fine concavo-convex structure of the transparent protective film is formed by, for example, applying metal to the surface of the transparent protective layer by an appropriate method such as a vacuum deposition method, an ion plating method, a sputtering method, or a plating method. It can be performed by a method of attaching directly to the screen.

  Instead of the method of directly applying the reflecting plate to the transparent protective film of the polarizing plate, the reflecting plate can be used as a reflecting sheet provided with a reflecting layer on an appropriate film according to the transparent film. Since the reflective layer is usually made of metal, the usage form in which the reflective surface is covered with a transparent protective film, a polarizing plate or the like is used to prevent the reflectance from being lowered due to oxidation, and thus to maintain the initial reflectance for a long time. In addition, it is more preferable to avoid a separate attachment of the protective layer.

  The semi-transmissive polarizing plate can be obtained by using a semi-transmissive reflective layer such as a half mirror that reflects and transmits light with the reflective layer. A transflective polarizing plate is usually provided on the back side of a liquid crystal cell, and displays an image by reflecting incident light from the viewing side (display side) when a liquid crystal display device is used in a relatively bright atmosphere. In a relatively dark atmosphere, a liquid crystal display device of a type that displays an image using a built-in power source such as a backlight built in the back side of the transflective polarizing plate can be formed. In other words, the transflective polarizing plate can be used to form liquid crystal display devices that can save energy when using a light source such as a backlight in a bright atmosphere and can be used with a built-in power supply even in a relatively dark atmosphere. It is.

  An elliptically polarizing plate or a circularly polarizing plate in which a retardation plate is further laminated on a polarizing plate will be described. A phase difference plate or the like is used when changing linearly polarized light to elliptically polarized light or circularly polarized light, changing elliptically polarized light or circularly polarized light to linearly polarized light, or changing the polarization direction of linearly polarized light. In particular, a so-called quarter-wave plate (also referred to as a λ / 4 plate) is used as a retardation plate that changes linearly polarized light into circularly polarized light or changes circularly polarized light into linearly polarized light. A half-wave plate (also referred to as a λ / 2 plate) is usually used when changing the polarization direction of linearly polarized light.

  The elliptically polarizing plate is effectively used for black and white display without the above color by compensating (preventing) the coloration (blue or yellow) generated by the birefringence of the liquid crystal layer of the super twist nematic (STN) type liquid crystal display device. It is done. Further, the one in which the three-dimensional refractive index is controlled is preferable because it can compensate (prevent) coloring that occurs when the screen of the liquid crystal display device is viewed from an oblique direction. The circularly polarizing plate is effectively used, for example, when adjusting the color tone of an image of a reflective liquid crystal display device in which an image is displayed in color, and also has an antireflection function.

  The elliptical polarizing plate and the reflective elliptical polarizing plate are obtained by laminating a polarizing plate or a reflective polarizing plate and a retardation plate in an appropriate combination. Such an elliptically polarizing plate or the like can also be formed by sequentially laminating them sequentially in the manufacturing process of the liquid crystal display device so as to be a combination of a (reflective) polarizing plate and a retardation plate. An optical film such as a polarizing plate has an advantage that it can improve the production efficiency of a liquid crystal display device and the like because of excellent quality stability and lamination workability.

  The visual compensation film is a film for widening the viewing angle so that the image can be seen relatively clearly even when the screen of the liquid crystal display device is viewed from a slightly oblique direction rather than perpendicular to the screen. Examples of such a visual compensation phase difference plate include a phase difference plate, an alignment film such as a liquid crystal polymer, and a film in which an alignment layer such as a liquid crystal polymer is supported on a transparent substrate. A normal retardation plate uses a birefringent polymer film that is uniaxially stretched in the plane direction, whereas a retardation plate used as a visual compensation film is biaxially stretched in the plane direction. Birefringent polymer film, biaxially stretched film such as polymer with birefringence with a controlled refractive index in the thickness direction that is uniaxially stretched in the plane direction and stretched in the thickness direction, etc. Used. Examples of the inclined alignment film include a film obtained by bonding a heat shrink film to a polymer film and stretching or / and shrinking the polymer film under the action of the contraction force by heating, and a film obtained by obliquely aligning a liquid crystal polymer. can give. The raw material polymer for the phase difference plate is the same as the polymer described in the previous phase difference plate, preventing coloration due to a change in the viewing angle based on the phase difference by the liquid crystal cell and expanding the viewing angle for good visual recognition. An appropriate one for the purpose can be used.

  In addition, from the viewpoint of achieving a wide viewing angle with good visibility, an optical compensation position in which an alignment layer of a liquid crystal polymer, particularly an optically anisotropic layer composed of a tilted alignment layer of a discotic liquid crystal polymer, is supported by a triacetyl cellulose film. A phase difference plate can be preferably used.

  A polarizing plate obtained by bonding a polarizing plate and a brightness enhancement film is usually provided on the back side of a liquid crystal cell. The brightness enhancement film reflects a linearly polarized light with a predetermined polarization axis or a circularly polarized light in a predetermined direction when natural light is incident due to a backlight such as a liquid crystal display device or reflection from the back side, and transmits other light. In addition, a polarizing plate in which a brightness enhancement film is laminated with a polarizing plate allows light from a light source such as a backlight to enter to obtain transmitted light in a predetermined polarization state, and reflects light without transmitting the light other than the predetermined polarization state. The The light reflected on the surface of the brightness enhancement film is further inverted through a reflective layer or the like provided behind the brightness enhancement film and re-incident on the brightness enhancement film, and part or all of the light is transmitted as light having a predetermined polarization state. Luminance can be improved by increasing the amount of light transmitted through the enhancement film and increasing the amount of light that can be used for liquid crystal display image display or the like by supplying polarized light that is difficult to be absorbed by the polarizer. That is, when light is incident through the polarizer from the back side of the liquid crystal cell without using a brightness enhancement film, light having a polarization direction that does not coincide with the polarization axis of the polarizer is almost polarized. It is absorbed by the polarizer and does not pass through the polarizer. That is, although depending on the characteristics of the polarizer used, approximately 50% of the light is absorbed by the polarizer, and accordingly, the amount of light that can be used for liquid crystal image display or the like is reduced and the image becomes dark. The brightness enhancement film reflects light that has a polarization direction that is absorbed by the polarizer without being incident on the polarizer, and is reflected by the brightness enhancement film, and then inverted through a reflective layer or the like provided behind the brightness enhancement film. The brightness enhancement film transmits only the polarized light in which the polarization direction of the light reflected and inverted between the two is allowed to pass through the polarizer. Since the light is supplied to the polarizer, light such as a backlight can be efficiently used for displaying an image on the liquid crystal display device, and the screen can be brightened.

  A diffusion plate may be provided between the brightness enhancement film and the reflective layer. The polarized light reflected by the brightness enhancement film is directed to the reflective layer or the like, but the installed diffuser plate uniformly diffuses the light passing therethrough and simultaneously cancels the polarized state and becomes a non-polarized state. That is, the light in the natural light state is directed toward the reflection layer or the like, reflected through the reflection layer or the like, and again passes through the diffusion plate and reenters the brightness enhancement film. In this way, by providing a diffuser plate that returns polarized light to the original natural light between the brightness enhancement film and the reflective layer, the brightness of the display screen is maintained, and at the same time, the brightness of the display screen is reduced and uniform. Can provide a bright screen. By providing such a diffuser plate, it is considered that the first incident light has a moderate increase in the number of repetitions of reflection, and in combination with the diffusion function of the diffuser plate, a uniform bright display screen can be provided.

  The brightness enhancement film has a characteristic of transmitting linearly polarized light having a predetermined polarization axis and reflecting other light, such as a multilayer thin film of dielectric material or a multilayer laminate of thin film films having different refractive index anisotropies. Such as an alignment film of a cholesteric liquid crystal polymer or an alignment liquid crystal layer supported on a film substrate, which reflects either left-handed or right-handed circularly polarized light and transmits other light. Appropriate things, such as a thing, can be used.

  Therefore, in the brightness enhancement film of the type that transmits linearly polarized light having the predetermined polarization axis as described above, the transmitted light is incident on the polarizing plate with the polarization axis aligned as it is, thereby efficiently transmitting while suppressing absorption loss due to the polarizing plate. Can be made. On the other hand, in a brightness enhancement film of a type that transmits circularly polarized light such as a cholesteric liquid crystal layer, it can be incident on a polarizer as it is, but from the point of suppressing absorption loss, the circularly polarized light is converted into linearly polarized light through a retardation plate. It is preferably incident on the polarizing plate. Note that circularly polarized light can be converted to linearly polarized light by using a quarter wave plate as the retardation plate.

  A retardation plate that functions as a quarter-wave plate at a wide wavelength in the visible light region or the like exhibits, for example, a retardation plate that functions as a quarter-wave plate for light-colored light having a wavelength of 550 nm and other retardation characteristics. It can be obtained by a method in which a phase difference layer, for example, a phase difference layer that functions as a half-wave plate is superimposed. Therefore, the retardation plate disposed between the polarizing plate and the brightness enhancement film may be composed of one or more retardation layers.

  In addition, a cholesteric liquid crystal layer having a reflection structure that reflects circularly polarized light in a wide wavelength range such as a visible light range can be obtained by combining two or more layers with different reflection wavelengths to form an overlapping structure. Based on this, transmitted circularly polarized light in a wide wavelength range can be obtained.

  Further, the polarizing plate may be formed by laminating a polarizing plate and two or more optical layers as in the above-described polarization separation type polarizing plate. Therefore, a reflective elliptical polarizing plate or a semi-transmissive elliptical polarizing plate in which the above-described reflective polarizing plate or semi-transmissive polarizing plate and a retardation plate are combined may be used.

  An optical film in which the optical layer is laminated on a polarizing plate can be formed by a method of sequentially laminating separately in the manufacturing process of a liquid crystal display device or the like. There is an advantage that the manufacturing process of a liquid crystal display device or the like can be improved because of excellent stability and assembly work. For the lamination, an appropriate adhesive means such as an adhesive layer can be used. When adhering the polarizing plate and the other optical layer, their optical axes can be set at an appropriate arrangement angle in accordance with the target retardation characteristics.

  In addition, each layer such as an optical film or an adhesive layer of the pressure-sensitive adhesive optical film of the present invention includes, for example, an ultraviolet ray such as a salicylic acid ester compound, a benzophenol compound, a benzotriazole compound, a cyanoacrylate compound, or a nickel complex compound. What gave the ultraviolet absorptivity by systems, such as a system processed with an absorber, may be used.

  The pressure-sensitive adhesive optical film of the present invention can be preferably used for forming various image display devices such as liquid crystal display devices. The liquid crystal display device can be formed according to the conventional method. That is, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell, an adhesive optical film, and an illumination system as necessary, and incorporating a drive circuit. There is no particular limitation except that an adhesive optical film is used. As the liquid crystal cell, an arbitrary type such as an arbitrary type such as a TN type, STN type, π type, VA type, or IPS type can be used.

  An appropriate liquid crystal display device such as 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 backlight or a reflector used in an illumination system can be formed. In that case, the optical film according to the present invention can be installed on one side or both sides of the liquid crystal cell. When optical films are provided on both sides, they may be the same or different. Further, when forming a liquid crystal display device, for example, a single layer or a suitable part such as a diffusing plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusing plate, a backlight, etc. Two or more layers can be arranged.

  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. Generally, in an organic EL display device, a transparent electrode, an organic light emitting layer, and a metal electrode are sequentially laminated on a transparent substrate to form a light emitter (organic electroluminescent light emitter). Here, the organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative and the like and a light emitting layer made of a fluorescent organic solid such as anthracene, Alternatively, a structure having various combinations such as a laminate of such a light-emitting layer and an electron injection layer composed of a perylene derivative or the like, or a laminate of these hole injection layer, light-emitting layer, and electron injection layer is known. It has been.

  In organic EL display devices, holes and electrons are injected into the organic light-emitting layer by applying a voltage to the transparent electrode and the metal electrode, and the energy generated by recombination of these holes and electrons excites the phosphor material. Then, light is emitted on the principle that the excited fluorescent material emits light when returning to the ground state. The mechanism of recombination in the middle is the same as that of a general diode, and as can be predicted from this, the current and the emission intensity show strong nonlinearity with rectification with respect to the applied voltage.

  In an organic EL display device, in order to extract light emitted from the organic light emitting layer, at least one of the electrodes must be transparent, and a transparent electrode usually formed of a transparent conductor such as indium tin oxide (ITO) is used as an anode. It is used as. On the other hand, in order to facilitate electron injection and increase luminous efficiency, it is important to use a material having a small work function for the cathode, and usually metal electrodes such as Mg—Ag and Al—Li are used.

  In the organic EL display device having such a configuration, the organic light emitting layer is formed of a very thin film having a thickness of about 10 nm. For this reason, the organic light emitting layer transmits light almost completely like the transparent electrode. As a result, light that is incident from the surface of the transparent substrate at the time of non-light emission, passes through the transparent electrode and the organic light emitting layer, and is reflected by the metal electrode is again emitted to the surface side of the transparent substrate. The display surface of the organic EL display device looks like a mirror surface.

  In an organic EL display device comprising an organic electroluminescent light emitting device comprising a transparent electrode on the surface side of an organic light emitting layer that emits light upon application of a voltage and a metal electrode on the back side of the organic light emitting layer, the surface of the transparent electrode While providing a polarizing plate on the side, a retardation plate can be provided between the transparent electrode and the polarizing plate.

  Since the retardation plate and the polarizing plate have a function of polarizing light incident from the outside and reflected by the metal electrode, there is an effect that the mirror surface of the metal electrode is not visually recognized by the polarization action. In particular, the mirror surface of the metal electrode can be completely shielded by configuring the retardation plate with a quarter-wave plate and adjusting the angle formed by the polarization direction of the polarizing plate and the retardation plate to π / 4. .

  That is, only the linearly polarized light component of the external light incident on the organic EL display device is transmitted by the polarizing plate. This linearly polarized light becomes generally elliptically polarized light by the phase difference plate, but becomes circularly polarized light particularly when the phase difference plate is a quarter wavelength plate and the angle formed by the polarization direction of the polarizing plate and the phase difference plate is π / 4. .

  This circularly polarized light is transmitted through the transparent substrate, the transparent electrode, and the organic thin film, is reflected by the metal electrode, is again transmitted through the organic thin film, the transparent electrode, and the transparent substrate, and becomes linearly polarized light again on the retardation plate. And since this linearly polarized light is orthogonal to the polarization direction of a polarizing plate, it cannot permeate | transmit a polarizing plate. As a result, the mirror surface of the metal electrode can be completely shielded.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In addition, all the parts and% in each example are based on weight.
Evaluation items in Examples and the like were measured as follows.

<Measurement of weight average molecular weight>
The weight average molecular weight of the obtained (meth) acrylic polymer was measured by GPC (gel permeation chromatography). The sample was prepared by dissolving the sample in dimethylformamide to give a 0.1% by weight solution, which was allowed to stand overnight and then filtered through a 0.45 μm membrane filter.
・ Analyzer: HLC-8120GPC manufactured by Tosoh Corporation
Column: Super AWM-H, AW4000, AW2500, manufactured by Tosoh Corporation
・ Column size: 6.0mmφ × 150mm each
・ Eluent: 30 mM-lithium bromide, 30 mM-phosphoric acid in dimethylformamide solution ・ Flow rate: 0.4 ml / min
・ Detector: Differential refractometer (RI)
-Column temperature: 40 ° C
・ Injection volume: 20 μl

(Creation of polarizing plate)
A polyvinyl alcohol film having a thickness of 80 μm was stretched up to 3 times while being dyed for 1 minute in an iodine solution of 0.3% concentration at 30 ° C. between rolls having different speed ratios. Thereafter, the total draw ratio was stretched to 6 times while being immersed in an aqueous solution containing 60% at 4% concentration of boric acid and 10% concentration of potassium iodide for 0.5 minutes. Next, after washing by immersing in an aqueous solution containing potassium iodide at 30 ° C. and 1.5% concentration for 10 seconds, drying was performed at 50 ° C. for 4 minutes to obtain a polarizer. A saponified 80 μm thick triacetyl cellulose film was bonded to both surfaces of the polarizer with a polyvinyl alcohol-based adhesive to prepare a polarizing plate.

Production Example 1
<Preparation of acrylic polymer>
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube and a condenser, 99.1 parts of butyl acrylate, 0.1 part of N, N-dimethylaminoethyl acrylate, 0.3 part of acrylic acid, 4 -0.5 part of hydroxybutyl acrylate and 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator were charged together with 200 parts of ethyl acetate, and nitrogen gas was introduced while gently stirring to replace the nitrogen. Thereafter, a polymerization reaction was carried out for 6 hours while maintaining the liquid temperature in the flask at around 60 ° C. to prepare an acrylic polymer solution. The acrylic polymer had a weight average molecular weight of 2,050,000.

Production Examples 2 to 25
In Production Example 1, an acrylic polymer solution was prepared in the same manner as in Example 1 except that at least one of the types and amounts used of the monomer components was changed as shown in Table 1. . Table 1 shows the weight average molecular weight of the acrylic polymer obtained in each example.

Example 1
(Preparation of polarizing plate with adhesive layer)
With respect to 100 parts of the solid content of the acrylic polymer solution obtained in Production Example 1, 0.35 parts of polyol-modified hexamethylene diisocyanate (D160N manufactured by Mitsui Takeda Polyurethane Co., Ltd.) and 0.2 parts of silane as a crosslinking agent. An acrylic pressure-sensitive adhesive solution containing a coupling agent (KBE573, manufactured by Shin-Etsu Chemical Co., Ltd.) was prepared.

  Next, the acrylic pressure-sensitive adhesive solution is dried on one side of a polyethylene-treated terephthalate (PET) film (Mitsubishi Chemical Polyester Film Co., Ltd., MRF38) subjected to silicone treatment, and the thickness of the pressure-sensitive adhesive layer after drying becomes 20 μm. And then dried at 155 ° C. for 3 minutes to form an adhesive layer. The pressure-sensitive adhesive layer was bonded to a polarizing plate and transferred to prepare a polarizing plate with a pressure-sensitive adhesive layer.

Examples 2 to 25, Comparative Examples 1 to 12
In Example 1, except that the type of acrylic polymer solution used for the preparation of the acrylic pressure-sensitive adhesive solution, the type or amount of crosslinking agent, and the type or amount of silane coupling agent were changed as shown in Table 2. Produced a polarizing plate with an adhesive layer in the same manner as in Example 1.

  The following evaluation was performed about the polarizing plate (sample) with an adhesive layer obtained by the said Example and comparative example. The evaluation results are shown in Table 2.

<Measurement of initial adhesive strength>
The sample is cut to a width of 25 mm, and is attached to a non-alkali glass (Corning Corp., 1737) with a thickness of 0.7 mm by one-way reciprocating with a 2 kg roller, and then 15 minutes in an autoclave at 50 ° C. and 0.5 Mpa. After the treatment, it was then cured at 23 ° C. for 1 hour. The adhesive strength (N / 25 mm) when the sample was peeled off with a tensile tester at a peeling angle of 180 ° and a peeling speed of 300 mm / min was measured. The treatment for 15 minutes in an autoclave at 50 ° C. and 0.5 Mpa simulates the autoclave treatment performed when the adhesive optical film is attached to a liquid crystal cell or the like.

<Measurement of adhesive strength after 60 ° C./48 hours>
The sample is cut to a width of 25 mm, and is attached to a non-alkali glass (Corning Corp., 1737) with a thickness of 0.7 mm by one-way reciprocating with a 2 kg roller, and then 15 minutes in an autoclave at 50 ° C. and 0.5 Mpa. After the treatment, it was then cured at 60 ° C. for 48 hours. The adhesive strength (N / 25 mm) when the sample was peeled off with a tensile tester at a peeling angle of 180 ° and a peeling speed of 300 mm / min was measured.

<Reworkability>
The sample was cut to a width of 25 mm, attached to a non-alkali glass having a thickness of 0.7 mm (Corning Corp., 1737) with a 2 kg roller, and then cured at 23 ° C. for 1 hour. This sample was visually evaluated with the following criteria for the adhesive force (N / 25 mm) and the state of the glass surface when the sample was peeled off at a peeling angle of 180 ° and a peeling speed of 300 mm / min.
(Double-circle): It can peel without adhesive residue (adhesive force: less than 10N / 25mm).
○: Peelable with no adhesive residue but slightly heavy peel (adhesive strength: 10 N / 25 mm or more and less than 15 N / 25 mm).
Δ: Peelable without adhesive residue, but heavy peeling (adhesive strength: 15 N / 25 mm or more).
X: A slight adhesive residue.
XX: Adhesive residue generated.

<Measurement of gel fraction>
The gel fraction is evaluated by using it in the composition stage before preparing the samples of the above examples and comparative examples. Each composition was applied to the release-treated polyester film so that the thickness after drying was 25 μm, and the gel fraction 1 hour after the application was measured. The gel fraction is a fluororesin (TEMISH NTF-1122, manufactured by Nitto Denko Corporation), which is 0.2 g of pressure-sensitive adhesive on the support after being applied and subjected to conditions of a temperature of 23 ° C. and a humidity of 65% RH. ) After wrapping in (W _a ) and binding the adhesive so that it does not leak, the weight (W _b ) was measured and placed in a sample bottle. 40 cc of ethyl acetate was added and left for 7 days. Thereafter, the fluororesin was taken out, dried on an aluminum cup at 130 ° C. for 2 hours, the weight (Wc) 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, quick crosslinkability>
Whether or not there is a sticky feeling on the side surface of the polarizing plate as observed by the operator's eyes and hands with respect to 100 pieces punched into a square having a side length of 270 mm within 24 hours after the above sample was prepared. Or? Moreover, it was judged whether the surface of the polarizing plate was soiled by the adhesive. The following criteria were used to evaluate how many sheets were free from stickiness and dirt.
○: 0 out of 100 sheets.
Δ: 1 to 5 out of 100 sheets.
X: 6 or more out of 100 sheets.

<Number of dents generated>
The sample was cut into 350 mm × 250 mm, stacked 20 sheets in the same direction so that the polarizing plate was on top, and a 2 kg weight was placed on the uppermost polarizing plate, and left in that state for one week at room temperature. . Thereafter, whether or not dents were generated and the number thereof were visually confirmed.
◎: 0 ○ ○: 1 to 3 ×: 4 or more

<Durability>
The sample is cut into 320 mm × 240 mm, attached to a non-alkali glass (Corning Corp., 1737) with a thickness of 0.7 mm, and processed in an autoclave at 50 ° C. and 0.5 Mpa for 15 minutes to complete the sample. It was made to adhere to non-alkali glass. Samples that have been subjected to such treatment are subjected to treatment for 500 hours under the conditions of 80 ° C., 90 ° C., 100 ° C., 60 ° C./90% RH, and 60 ° C./95% RH. The following criteria were used for visual evaluation.
A: No foaming or peeling.
◯: Foaming (maximum diameter less than 100 μm) that does not affect visibility is observed.
X: Foaming (maximum diameter 100 μm or more), peeling is recognized.

  In Table 1, BA: butyl acrylate, DMAEA: N, N-dimethylaminoethyl acrylate, DMAPAA: N, N-dimethylaminopropyl acrylamide, ACMO: N-acryloylmorpholine, AAM: acrylamide, AA: acrylic acid, 4HBA: 4 -Hydroxybutyl acrylate, 2HEA: 2-hydroxyethyl acrylate, PEA: phenoxyethyl acrylate.

  In Table 2, the isocyanate-based cross-linking agent is polyol-modified hexamethylene diisocyanate (manufactured by Mitsui Takeda Polyurethane Co., Ltd., D160N), polyol-modified hydrogenated xylylene diisocyanate (manufactured by Mitsui Takeda Polyurethane Co., Ltd., D120N), polyol-modified isophorone diisocyanate. (Mitsui Takeda Polyurethane Co., Ltd., D140N), Trimer hydrogenated xylylene diisocyanate (Mitsui Takeda Polyurethane Co., Ltd., D127N), Polyol-modified Tolylene Diisocyanate (Nippon Polyurethane Industry Co., Ltd. C / L), Polyol Modified xylene diisocyanate (D110N, manufactured by Mitsui Takeda Polyurethane Co., Ltd.). The silane coupling agent is KBM573 or KBM403 manufactured by Shin-Etsu Chemical Co., Ltd. * Oligomer of the other additive of Comparative Example 10 is 15 parts of an acrylic oligomer (weight average molecular weight 3000, manufactured by Toagosei Co., Ltd., ARFONUP-1000).

Claims (7)

As monomer units, (a) alkyl (meth) acrylate 50 to 99.79% by weight, (b) tertiary amino group-containing monomer 0.01 to 0.45% by weight, and (c) hydroxyl group-containing monomer 0. A (meth) acrylic polymer comprising 1 to 3% by weight and having a weight average molecular weight of 1.5 million to 3.5 million; and
As a crosslinking agent, selected hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, Lee isophorone diisocyanate, polyol-modified hexamethylene diisocyanate, polyol-modified hydrogenated xylylene diisocyanate, trimer type hydrogenated xylylene diisocyanate, and from the group consisting of polyol-modified isophorone diisocyanate An optical film pressure-sensitive adhesive composition comprising 0.01 to 2 parts by weight of one or two or more of the above , based on 100 parts by weight of the (meth) acrylic polymer. The (meth) acrylic polymer further, (d) according to claim 1 for an optical film pressure-sensitive adhesive composition, wherein the comprising 0.1 to 3 wt% carboxyl group-containing monomer.   The adhesive for optical films according to claim 1, further comprising 0.01 to 1 part by weight of a silane coupling agent with respect to 100 parts by weight of the (meth) acrylic polymer. Agent composition.   The pressure-sensitive adhesive composition for an optical film according to claim 3, wherein the silane coupling agent has an amino group.   It is obtained by applying the cross-linking reaction by applying the pressure-sensitive adhesive composition for an optical film according to any one of claims 1 to 4, and the gel fraction after 1 hour of application is 55 to 95%. A pressure-sensitive adhesive layer for optical films.   An adhesive optical film, wherein the optical film adhesive layer according to claim 5 is formed on at least one side of the optical member.   An image display device comprising at least one adhesive optical film according to claim 6.