JP2009298906A - Adhesive composition for optical film, adherent-type optical film and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition for an optical film, which can form an adhesive layer that can suppress the light leakage caused due to the stress accompanied by the dimensional change of a member such as an optical film, and to provide an adherent-type optical film and the like using the same. <P>SOLUTION: The adhesive composition for the optical film is prepared which contains a (meth)acrylic copolymer and 0.001-20 pts.wt. of an aromatic polyisocyanate compound having a specific structure, based on 100 pts.wt. of the (meth)acrylic copolymer. The (meth)acrylic copolymer can contain an alkyl (meth)acrylate and a hydroxyl group-containing monomer as the monomer units. The aromatic polyisocyanate compound can be a polymeric MDI and the like. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pressure-sensitive adhesive composition for optical films that requires light leakage resistance and the like, 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.

  As a necessary characteristic required for the pressure-sensitive adhesive, there is suppression of a light leakage phenomenon which is considered to be caused by a phase difference generated in the pressure-sensitive adhesive layer, particularly in an optical film.

  Conventionally, a method of adding a plasticizer or an oligomer to an adhesive has been proposed for improving light leakage of an image display device produced using an optical film (Patent Documents 1 and 2).

In addition, a pressure-sensitive adhesive composition based on a polymer obtained by copolymerizing an acrylic ester, an aromatic ring-containing monomer, and a hydroxyl group-containing monomer has been proposed in an attempt to balance light leakage and other characteristics (Patent Document). 3 and 4).
Patent No. 3594206 Japanese Patent No. 3533589 JP 2007-138057 A JP 2007-138056 A

  The present invention provides a pressure-sensitive adhesive composition for an optical film capable of forming a pressure-sensitive adhesive layer that can suppress light leakage caused by stress accompanying a dimensional change of a member such as an optical film and can satisfy light leakage resistance. For the purpose.

  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.

（ここで、ｎは、２〜４０の整数を表し、Ｒ_１、Ｒ_２、Ｒ_３のうち少なくとも１つは、イソシアネート基であり、残りは、水素または炭素数１から１０までのアルキル基のいずれかの基を表す）。 That is, the present invention relates to an aromatic polyisocyanate compound represented by the following formula (1) with respect to 100 parts by weight of a (meth) acrylic copolymer; and the (meth) acrylic copolymer. About the adhesive composition for optical films characterized by containing 20 weight part:

(Here, n represents an integer of 2 to 40, and at least one of R ₁ , R ₂ , and R ₃ is an isocyanate group, and the rest is hydrogen or an alkyl group having 1 to 10 carbon atoms. Represents any group).

  In the optical film pressure-sensitive adhesive composition, the (meth) acrylic copolymer preferably contains 50% by weight or more of alkyl (meth) acrylate as a monomer unit.

  In the optical film pressure-sensitive adhesive composition, the (meth) acrylic copolymer contains 0.01 to 10% by weight of a hydroxyl group-containing monomer as a monomer unit with respect to the total amount of the (meth) acrylic copolymer. Is preferred.

  In the optical film pressure-sensitive adhesive composition, the (meth) acrylic copolymer is further selected from the group consisting of a carboxyl group-containing monomer, an amino group-containing monomer, and an amide group-containing monomer as a monomer unit. It is preferable to contain 0.01 to 30% by weight of one monomer.

  In the optical film pressure-sensitive adhesive composition, the (meth) acrylic copolymer preferably has a weight average molecular weight of 300,000 to 1,500,000 by gel permeation chromatography.

  In the optical film pressure-sensitive adhesive composition, it is preferable to contain 0.01 to 10 parts by weight of a silane coupling agent with respect to 100 parts by weight of the (meth) acrylic copolymer.

  The present invention also relates to an optical film pressure-sensitive adhesive layer obtained by coating one of the above optical film pressure-sensitive adhesive compositions and causing a crosslinking reaction.

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

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

  The pressure-sensitive adhesive composition for optical films of the present invention contains a (meth) acrylic copolymer that is a base polymer, and contains an aromatic polyisocyanate compound having a specific structure. The optical member obtained from such an optical film pressure-sensitive adhesive composition has light leakage suppressed.

  The pressure-sensitive adhesive composition for an optical film of the present invention contains a (meth) acrylic copolymer as a base polymer.

  Here, the monomer which comprises a (meth) acrylic-type copolymer is not specifically limited, For example, an alkyl (meth) acrylate or aromatic (meth) acrylate etc. are included as a monomer unit. In particular, the monomer unit preferably contains 50% by weight or more of alkyl (meth) acrylate, and may optionally contain 0.01 to 10% by weight of hydroxyl group-containing (meth) acrylate.

  In this specification, the term “alkyl (meth) acrylate” refers to a (meth) acrylate having a linear or branched alkyl group having 2 to 18 carbon atoms, and includes an aromatic ring in the structure. Is excluded. 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 this invention, it is preferable that the said alkyl (meth) acrylate is 50 to 99 weight% with respect to all the monomer components of a (meth) acrylic-type copolymer, Furthermore, 60 to 99 weight%, More preferably 72 to 85% by weight.

  In the present invention, an aromatic ring-containing (meth) acrylate may be further included. The term “aromatic ring-containing (meth) acrylate” is a copolymerizable (meth) acrylate containing an aromatic group in its structure. Examples of aromatic ring-containing (meth) acrylates include phenyl acrylate, phenoxy (meth) acrylate, phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, ethylene oxide modified nonylphenol (meth) acrylate, Examples thereof include hydroxyethylated β-naphthol acrylate and biphenyl (meth) acrylate. Further, for example, phenol ethylene oxide modified (meth) acrylate, 2-naphthoethyl (meth) acrylate, 2-naphthoxyethyl acrylate, 2- (4-methoxy-1-naphthoxy) ethyl (meth) acrylate, phenoxypropyl (meth) Examples include acrylate, phenoxydiethylene glycol (meth) acrylate, thiol acrylate, pyridyl acrylate, pyrrole acrylate, phenyl acrylate, and polystyryl (meth) acrylate.

  In this invention, when the said aromatic ring containing (meth) acrylate is contained, it is preferable that it is 10 to 45 weight% with respect to all the monomer components of a (meth) acrylic-type copolymer. Furthermore, it is more preferably 10 to 40% by weight, and most preferably 20 to 35% by weight. Thus, when the (meth) acrylic copolymer of the present invention contains an aromatic ring-containing (meth) acrylate, it is necessary to balance the content ratio of the aromatic ring-containing (meth) acrylate and the alkyl (meth) acrylate. is there.

  The (meth) acrylic copolymer of the present invention preferably contains a hydroxyl group-containing monomer, that is, a hydroxyl group-containing (meth) acrylate. As such a monomer, those having a polymerizable functional group having an unsaturated double bond of a (meth) acryloyl group and having a hydroxyl group can be used without particular limitation. Examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 6-hydroxy. Hexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, hydroxyalkyl (meth) acrylate such as 12-hydroxylauryl (meth) acrylate; hydroxyethyl (meth) acrylamide, etc. (4-hydroxymethylcyclohexyl) methyl acrylate, N-methylol (meth) acrylamide, N-hydroxy (meth) acrylamide; polyoxypropylene (meth) acrylate, cap Lactone-modified (meth) acrylate and the like. Of these, preferably hydroxyalkyl acrylate, more preferably 4-hydroxybutyl acrylate.

  The hydroxyl group-containing (meth) acrylate is used in a proportion of 0.01 to 10% by weight with respect to the total amount of monomer components forming the (meth) acrylic copolymer. The proportion of the hydroxyl group-containing (meth) acrylate is preferably 0.05 to 5% by weight, more preferably 0.1 to 1% by weight. When the hydroxyl group-containing (meth) acrylate is 10% by weight or more, the tackiness of the pressure-sensitive adhesive is lost and the pressure-sensitive adhesive properties are not exhibited. On the other hand, in the case of 0.01% by weight or more, a crosslinking point with isocyanate is ensured, and durability can be satisfied.

  In addition to this, the (meth) acrylic copolymer of the present invention optionally includes at least one monomer selected from the group consisting of a carboxyl group-containing monomer, an amino group-containing monomer, and an amide group-containing monomer, or A total of 0.01 to 30% by weight of two or more combinations may be included.

  Here, the carboxyl group-containing monomer is a carboxyl group-containing (meth) acrylate, for example, having a polymerizable functional group having an unsaturated double bond of a (meth) acryloyl group, and a carboxyl group. Those having the above can be used without particular limitation. Examples of the carboxyl group-containing (meth) acrylate include (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, and the like.

  The amino group-containing monomer is an amino group-containing (meth) acrylate, and examples thereof include N- (meth) acryloyloxymethylene succinimide and N- () as monomers other than tertiary amino group-containing (meth) acrylate. Succinimide monomers such as (meth) acryloyl-6-oxyhexamethylene succinimide and N- (meth) acryloyl-8-oxyoctamethylene succinimide; (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl N- such as (meth) acrylamide, N, N-diethylmethacrylamide, N-isopropyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, etc. Place Amide monomers; Monomers having secondary amino groups such as t-butylaminoethyl (meth) acrylate, diacetone (meth) acrylamide, N, N′-methylenebis (meth) acrylamide, N-acryloylmorpholine, N -Acryloylpiperidine, N-methacryloylpiperidine, N-acryloylpyrrolidine and the like can be used. However, tertiary amino group-containing (meth) acrylates are particularly preferred, and those containing various tertiary amino groups and (meth) acryloyl groups can be preferably used. The tertiary amino group is preferably a tertiary aminoalkyl group. Examples of such tertiary amino group-containing (meth) acrylates include N, N-dialkylaminoalkyl (meth) acrylamide and N, N-dialkylaminoalkyl (meth) acrylate. Specific examples of the tertiary amino group-containing (meth) acrylate include, for example, N, N-dimethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-diethylaminoethyl (meta) ) Acrylamide, N, N-diethylaminopropyl (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N , N-diethylaminopropyl (meth) acrylamide.

  Examples of the amide group-containing monomer include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-diethylmethacrylamide, N-isopropyl ( (Meth) acrylic amide, N-methylol (meth) acrylic amide, N-methoxymethyl (meth) acrylic amide, N-butoxymethyl (meth) acrylic amide, (meth) acrylic acid dimethylaminoethyl, (meth) acrylic acid t- Examples include butylaminoethyl, diacetone (meth) acrylamide, N-vinylacetamide, N, N′-methylenebis (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N-vinylcaprolactam, and the like. .

  As the monomer component for forming the (meth) acrylic copolymer, monomers other than those described above can be used in addition to the monomers as long as the object of the present invention is not impaired. The ratio of the optional monomer in the present invention is further preferably 40% by weight or less. Examples of such optional monomers include maleic anhydride, itaconic anhydride and other acid anhydride group-containing monomers; acrylic acid caprolactone adducts; styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid Sulfonic acid group-containing monomers such as (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalene sulfonic acid; phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate; (meth) acrylic acid (Meth) acrylic acid alkoxyalkyl monomers such as methoxyethyl 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.

The (meth) acrylic copolymer of the present invention has a weight average molecular weight (M _w ) in the range of 300,000 to 2,000,000 in consideration of durability, particularly heat resistance. Preferably, those in the range of 400,000 to 1.6 million are used. Furthermore, it is more preferable that it is 400,000-1.3 million. The weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene.

  For the production of such a (meth) acrylic copolymer, known production methods such as solution polymerization, bulk polymerization, emulsion polymerization, and various radical polymerizations can be appropriately selected. Further, the (meth) acrylic copolymer 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. The weight average molecular weight of the (meth) acrylic copolymer can be controlled by the amount of polymerization initiator, the amount of chain transfer agent used, and the reaction conditions, and the amount used is appropriately adjusted according to these types. .

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

  Examples of the chain transfer agent include 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 (manufactured by 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.

（ここで、ｎは、２〜４０の整数を表し、Ｒ_１、Ｒ_２、Ｒ_３のうち少なくとも１つは、イソシアネート基であり、残りは、水素または炭素数１から１０までのアルキル基のいずれかの基を表す）。 The pressure-sensitive adhesive composition of the present invention contains 0.001 to 20% by weight of an aromatic polyisocyanate compound. Preferably, it is 0.5 to 20% by weight. By using such an aromatic polyisocyanate compound, birefringence generated in the pressure-sensitive adhesive can be controlled, and light leakage around the optical film using the pressure-sensitive adhesive can be reduced. Here, the aromatic polyisocyanate compound is preferably a compound represented by the following formula (1).

(Here, n represents an integer of 2 to 40, and at least one of R ₁ , R ₂ , and R ₃ is an isocyanate group, and the rest is hydrogen or an alkyl group having 1 to 10 carbon atoms. Represents any group).

Among such aromatic polyisocyanate compounds, polymeric MDI in which all of R ₁ , R ₂ , and R ₃ are isocyanates is particularly preferable. As the polymeric MDI, any commercially available one may be used.

Alternatively, polymeric MDI is condensed with aniline in the presence of formaldehyde and an acid catalyst, the resulting polyamine mixture is reacted with phosgene in the presence of a solvent, and diphenylmethane diisocyanate is separated from the product by vacuum distillation. Can be obtained. Similarly, a compound in which any one of R ₁ , R ₂ and R ₃ is an isocyanate and the other group is hydrogen or an alkyl group having 1 to 10 carbon atoms is used as a starting material, such as benzene, toluene or other It can be produced by the same method using alkylbenzene.

  The pressure-sensitive adhesive composition of the present invention may also contain a silane coupling agent and a siloxane compound having a specific substituent.

  By using a silane coupling agent, the adhesive strength and durability of the pressure-sensitive adhesive composition are improved. Specific examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3, Epoxy group-containing silane coupling agents such as 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl- Amino group-containing silane coupling agents such as N- (1,3-dimethylbutylidene) propylamine, N-phenyl-γ-aminopropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltri (Meth) a, such as ethoxysilane Lil group-containing silane coupling agents, such as isocyanate group-containing silane coupling agents such as 3-isocyanate propyl triethoxysilane and the like. Among them, it is preferable to use an aromatic ring-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 can 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 based on 100 parts by weight of the (meth) acrylic copolymer. The silane coupling agent is preferably contained in an amount of 0.01 to 1 part by weight, more preferably 0.02 to 1 part by weight, and 0.05 to 0.6 part by weight. 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.

  In the present invention, a peroxide can be added as a crosslinking agent. As the peroxide, 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, in consideration of workability and stability. It is preferable to use a peroxide having a one-minute half-life temperature of 80 ° C. to 160 ° C., and more preferable to use a peroxide having a 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 100 parts by weight of the (meth) acrylic copolymer. On the other hand, 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. In order to adjust reworkability, cross-linking stability, peelability, etc., it is appropriately selected within this range.

  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 bonded or coordinated include an oxygen atom, and examples of the organic compound include an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound, and a ketone compound.

  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 you may carry out 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.

  A silicone release liner is preferably used as the release-treated separator. In the step of applying the adhesive composition of the present invention on such a liner and drying to form a pressure-sensitive adhesive layer, a method for drying the pressure-sensitive adhesive is appropriately employed depending on the purpose. obtain. Preferably, a method of heating and drying the coating film is used. The heat drying temperature is preferably 40 ° C to 200 ° C, more preferably 50 ° C to 180 ° C, and particularly preferably 70 ° C to 170 ° C. By setting the heating temperature within the above range, an adhesive having excellent adhesive properties can be obtained.

  As the drying time, an appropriate time can be adopted as appropriate. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, and particularly preferably 10 seconds to 5 minutes.

  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 2-50 micrometers, More preferably, it is 2-40 micrometers, More preferably, it is 5-35 micrometers.

  The gel fraction 1 hour after application of the pressure-sensitive adhesive layer of the present invention thus obtained is 40% to 95%, preferably 60 to 95%. Such a gel fraction means that the crosslinking speed is high 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.

  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 commercial products of triacetyl cellulose include trade names “UV-50”, “UV-80”, “SH-80”, “TD-80U”, “TD-TAC”, “UZ” manufactured by Fuji Film Co., Ltd. -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 40 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.), a 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 4).

^Wherein, R 1, ^{R 2} and ^{R 3} each independently represent a hydrogen atom or an organic residue having 1 to 40 carbon atoms. The organic residue may contain an oxygen atom.

  The content of the lactone ring structure represented by the general formula (Formula 4) 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 4) in the structure of the (meth) acrylic resin having a lactone ring structure is less than 5% by weight, heat resistance, solvent resistance, and surface hardness are reduced. May be insufficient. If the content of the lactone ring structure represented by the general formula (Chemical Formula 4) 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 moldability.

  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.

  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.

  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.

  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, any type such as a TN type, STN type, π type, VA type, IPS type, or the like 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.

  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. The room temperature standing conditions not specifically defined below are all 23 ° C. and 65% RH (1 hour). 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 copolymer 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: TSKgel Super HM-H / H4000 / H3000 / H2000
・ Column size: 6.0mmφ × 150mm each
・ Eluent: Tetrahydrofuran ・ Flow rate: 0.6 ml / min
・ Detector: Differential refractometer (RI)
-Column temperature: 40 ° C
・ Injection volume: 20 μl
・ Standard sample: Polystyrene

(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 reaction vessel equipped with a stirrer, a thermometer, a nitrogen gas introduction tube, and a cooling tube, 99.0 parts by weight of butyl acrylate, 1.0 part by weight of 4-hydroxybutyl acrylate, and 2,2′-azobis as a polymerization initiator After charging 0.1 parts by weight of isobutyronitrile with ethyl acetate and introducing nitrogen gas with gentle stirring to replace the nitrogen, the temperature of the liquid in the flask was kept at around 60 ° C. for 6 hours, An acrylic copolymer solution having a weight average molecular weight of 1,200,000 was prepared.

Production Example 2
The same procedure as in Production Example 1 was carried out except that ethyl acetate was changed to toluene to obtain a solution containing an acrylic copolymer having a polymerization average molecular weight of 600,000.

Production Example 3
In a reaction vessel equipped with a stirrer, a thermometer, a nitrogen gas introduction tube, and a cooling tube, 99.7 parts by weight of butyl acrylate, 0.3 part by weight of 4-hydroxybutyl acrylate, and 2,2′-azobis as a polymerization initiator After charging 0.1 parts by weight of isobutyronitrile together with a mixed solvent of ethyl acetate and toluene, nitrogen gas was introduced with gentle stirring and the atmosphere was replaced with nitrogen, and the liquid temperature in the flask was kept at around 60 ° C. for 6 hours. A polymerization reaction was performed to prepare an acrylic copolymer solution having a weight average molecular weight of 1,000,000.

Production Example 4
The same procedure as in Production Example 3 was carried out except that ethyl acetate was changed to toluene to obtain a solution containing an acrylic copolymer having a polymerization average molecular weight of 510,000.

Production Example 5
In a reaction vessel equipped with a stirrer, thermometer, nitrogen gas introduction tube, and cooling tube, 99.2 parts by weight of butyl acrylate, 0.3 part by weight of acrylic acid, 0.5 part by weight of hydroxyethyl acrylate, 2 as a polymerization initiator , 2'-Azobisisobutyronitrile was charged with 0.1 part by weight of toluene, nitrogen gas was introduced with gentle stirring and the atmosphere was replaced with nitrogen, and the liquid temperature in the flask was kept at around 60 ° C. for 6 hours. A polymerization reaction was carried out to prepare an acrylic copolymer solution having a weight average molecular weight of 1,050,000.

Example 1
(Preparation of adhesive optical film)
Polymeric MDI (Millionate MR-100 manufactured by Nippon Polyurethane Industry Co., Ltd.) 0.1 part by weight per 100 parts by weight of the solid content of the acrylic copolymer solution obtained in Production Example 1, silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.) , KBM403) An acrylic pressure-sensitive adhesive solution containing 0.2 part by weight was prepared.

  Next, the acrylic pressure-sensitive adhesive solution was coated on a separator made of a 38 μm polyester film (MRF38, manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.) that had been subjected to silicone treatment, and heat-treated at 120 ° C. for 3 minutes to obtain a thickness. A 20 μm pressure-sensitive adhesive sheet was obtained. The pressure-sensitive adhesive layer was transferred to the polarizing plate by laminating the obtained pressure-sensitive adhesive sheet and the produced polarizing plate, thereby preparing a pressure-sensitive adhesive optical film.

Example 2
In the same manner as in Example 1 except that 1 part by weight of polymeric MDI (Millionate MR-100 manufactured by Nippon Polyurethane Industry) per 100 parts by weight of the solid content of the acrylic copolymer solution prepared in Production Example 2 was used. A mold optical film was prepared.

Example 3
The same method as in Example 1 except that the polymer MDI (Millionate MR-100 manufactured by Nippon Polyurethane Industry Co., Ltd.) was 0.3 parts by weight per 100 parts by weight of the solid content of the acrylic copolymer solution prepared in Production Example 3. An adhesive optical film was prepared.

Example 4
The same method as in Example 1 except that 1.5 parts by weight of polymeric MDI (Millionate MR-100 manufactured by Nippon Polyurethane Industry) per 100 parts by weight of the solid content of the acrylic copolymer solution prepared in Production Example 4 was used. An adhesive optical film was prepared.

Example 5
The same method as in Example 1 except that 0.5 parts by weight of polymeric MDI (Millionate MR-100 manufactured by Nippon Polyurethane Industry) per 100 parts by weight of the solid content of the acrylic copolymer solution prepared in Production Example 5 was used. An adhesive optical film was prepared.

Comparative Example 1
Polyol-modified tolylene diisocyanate (trimethylolpropane tolylene diisocyanate, C / L made by Nippon Polyurethane Industry) 0.3 parts by weight per 100 parts by weight of the solid content of the acrylic copolymer solution obtained in Production Example 1, silane coupling An acrylic pressure-sensitive adhesive solution containing 0.2 part by weight of an agent (manufactured by Shin-Etsu Chemical Co., Ltd., KBM403) was prepared.

  Next, the acrylic pressure-sensitive adhesive solution was coated on a separator made of a 38 μm polyester film (MRF38, manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.) that had been subjected to silicone treatment, and heat-treated at 120 ° C. for 3 minutes to obtain a thickness. A 20 μm pressure-sensitive adhesive sheet was obtained. The pressure-sensitive adhesive layer was transferred to the polarizing plate by laminating the obtained pressure-sensitive adhesive sheet and the produced polarizing plate, thereby preparing a pressure-sensitive adhesive optical film.

Comparative Example 2
Comparative Example, except that 1 part by weight of polyol-modified tolylene diisocyanate (trimethylolpropane tolylene diisocyanate, C / L made by Nippon Polyurethane Industry) per 100 parts by weight of the solid content of the acrylic copolymer solution prepared in Production Example 2 In the same manner as in Example 1, an adhesive optical film was produced.

  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 1.

<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 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)

<Adhesiveness>
Samples obtained in Examples and Comparative Examples were cut into a width of 25 mm and a length of 100 mm, and attached to a 0.5 mm-thick acrylic glass plate (Corning Corp., 1737) using a 2 kg roller, and then The film was autoclaved at 50 ° C. and 5 atm for 15 minutes for complete adhesion. The evaluation of adhesiveness was performed according to the following criteria.

  Here, the adhesive strength is measured when the sample is peeled off with a tensile tester (Autograph SHIMAZU AG-1 1OKN) at a peeling angle of 90 ° and a peeling speed of 300 mm / min (N / 25 mm, when measured). 80 m long). The measurement was sampled at an interval of 1 time / 0.5 s, and the average value was taken as the measurement value.

評価結果より、本発明の粘着剤層を有する光学フィルムは、光漏れ性を抑制し、かつ適度な接着力を保持していることが示された。 <Evaluation of light leakage>
The pressure-sensitive adhesive layers obtained in the examples and comparative examples were bonded to the produced polarizing plate, processed to a length of 100 mm × width of 75 mm, and a non-alkali glass plate having a thickness of 0.7 mm so as to be in a crossed Nicol state. It was stuck on one side and autoclaved at 50 ° C., 5 atm for 15 minutes to ensure complete adhesion. The sample was treated at 80 ° C. for 500 hours, then placed on a 10,000 candela backlight, and light leakage was visually confirmed according to the following criteria.
A: No light leakage and no problem with visibility.
○: Some light leakage occurs, but visibility is not affected.
X: Light leakage is observed, which affects the visibility.

From the evaluation results, it was shown that the optical film having the pressure-sensitive adhesive layer of the present invention suppressed light leakage and maintained an appropriate adhesive force.

Claims (9)

(Meth) acrylic copolymer; and 0.001 to 20 parts by weight of an aromatic polyisocyanate compound represented by the following formula (1) with respect to 100 parts by weight of the (meth) acrylic copolymer. An optical film pressure-sensitive adhesive composition comprising:

(Here, n represents an integer of 2 to 40, and at least one of R ₁ , R ₂ , and R ₃ is an isocyanate group, and the rest is hydrogen or an alkyl group having 1 to 10 carbon atoms. Represents any group).   The pressure-sensitive adhesive composition for an optical film according to claim 1, wherein the (meth) acrylic copolymer contains 50% by weight or more of alkyl (meth) acrylate as a monomer unit.   The said (meth) acrylic-type copolymer contains 0.01-10 weight% of hydroxyl-containing monomers as a monomer unit with respect to this (meth) acrylic-type copolymer whole quantity. The adhesive composition for optical films as described in any one of Claims 1-3.   The (meth) acrylic copolymer further contains 0.01 to 30 at least one monomer selected from the group consisting of a carboxyl group-containing monomer, an amino group-containing monomer, and an amide group-containing monomer as a monomer unit. The pressure-sensitive adhesive composition for an optical film according to claim 3, which is contained by weight%.   5. The pressure-sensitive adhesive for optical films according to claim 1, wherein the (meth) acrylic copolymer has a weight average molecular weight of 300,000 to 2,000,000 as determined by gel permeation chromatography. Composition.   6. The optical component according to claim 1, comprising 0.01 to 10 parts by weight of a silane coupling agent with respect to 100 parts by weight of the (meth) acrylic copolymer. Film pressure-sensitive adhesive composition.   An optical film pressure-sensitive adhesive layer obtained by coating the optical film pressure-sensitive adhesive composition according to any one of claims 1 to 6 to cause a crosslinking reaction.   An adhesive optical film, wherein the optical film pressure-sensitive adhesive layer according to claim 7 is formed on at least one side of the optical film.   An image display device using at least one adhesive optical film according to claim 8.