JP4880315B2 - Adhesive composition, adhesive layer, and optical member with adhesive - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive composition. Moreover, this invention relates to the adhesive layer formed with the said adhesive composition. Furthermore, this invention provides the optical member with an adhesive which has the said adhesive layer, and an image display apparatus using the same.

  Examples of the optical member include a polarizing plate, a retardation plate, an optical compensation film, a brightness enhancement film, and those in which these are laminated. Examples of the image display device include a liquid crystal display device, an organic EL display device, and a PDP.

  In general, in a liquid crystal display, a retardation film is usually laminated in order to compensate for coloration of a liquid crystal layer and to compensate for a change in retardation due to a viewing angle. Such an optical material has a large expansion and contraction under conditions of high temperature and high humidity, and the resulting displacement, floating and peeling are likely to occur, and the adhesive is required to have durability that can cope with this.

  In recent years, the range of use of liquid crystal displays has become wider, and is increasingly used in harsh usage environments. Therefore, it is desired that sufficient durability can be exhibited even under a severer usage environment than before (for example, the adhesive strength does not change over a long period of time).

  As a more specific example, it is known that a polarizing plate, a retardation plate, and the like behave like shrinkage and expansion under high temperature and high humidity. In contrast to these behaviors, if the adhesion between the glass surface and the pressure-sensitive adhesive (pressure-sensitive adhesive) is weak, problems such as peeling and floating at high temperatures and high humidity have occurred. The following proposals have been made to solve these problems.

  For example, the proposal which introduce | transduces a silane coupling agent in order to improve adhesiveness with a glass base material is disclosed (for example, refer patent documents 1-3). In these proposals, durability under conditions of 80 ° C. to 100 ° C. and 60 ° C./90% RH is studied. However, in recent years, further durability has been demanded in the mobile field, especially in the vehicle-mounted applications, and the like, under high temperature and high humidity conditions, such as 110 ° C. or 70 ° C./95% RH. Even when left in an environment for a long time, it is desired that problems such as peeling and floating do not occur.

  Further, it has been found in the conventional proposal that the visibility is not sufficient under such harsh conditions, and particularly when used as an optical member, it has particularly excellent visibility in addition to the durability described above. It has been demanded.

Japanese Patent Laid-Open No. 7-20314 JP-A-8-104855 JP 2005-213341 A

  Therefore, the present invention, in order to cope with the above-described problems, does not cause floating or peeling even when stored for a long time under high temperature and high humidity conditions such as 110 ° C. and 70 ° C./95% RH after the crosslinking treatment. It aims at providing the adhesive composition excellent in visibility.

  Moreover, an object of this invention is to provide the adhesive layer formed with the said adhesive composition. Furthermore, an object of this invention is to provide the optical member with an adhesive which has the said adhesive layer, and an image display apparatus using the same.

  In order to achieve the above object, the present inventors have intensively studied the constitution of the pressure-sensitive adhesive composition, and as a result, by using the following pressure-sensitive adhesive composition, after the crosslinking treatment, 110 ° C. or 70 ° C./95% RH. Even when stored for a long time under high temperature and high humidity conditions such as the above, it was found that a pressure-sensitive adhesive layer excellent in visibility without floating or peeling was obtained, and the present invention was completed.

That is, the pressure-sensitive adhesive composition of the present invention is
As a monomer unit, a (meth) acrylic group represented by the general formula CH ₂ = C (R ^a ) COOR ^b (where R ^a is hydrogen or a methyl group, and R ^b is an alkyl group having 2 to 14 carbon atoms) To 100 parts by weight of (meth) acrylic polymer containing 30 to 98% by weight of monomer and 0.1 to 30% by weight of other polymerizable monomer,
It contains 0.02 to 5 parts by weight of a crosslinking agent and 0.001 to 5 parts by weight of an imidazolesilane compound represented by the following formula (1).

（ただし、上記式（１）において、Ｒ^１およびＲ^２は、水素原子または炭素数１〜６のアルキル基、Ｒ^３およびＲ^４は、炭素数１〜６のアルキル基、ならびにｎは１〜２０の整数である。また、ａは１〜３の整数、ｂは１〜３の整数、ならびにｃは０または１であり、かつａ＋ｂ＋ｃ＝４である。）

(In the above formula (1), R ¹ and R ² are hydrogen atoms or alkyl groups having 1 to 6 carbon atoms, R ³ and R ⁴ are alkyl groups having 1 to 6 carbon atoms, and n is 1 to 1) And a is an integer of 1 to 3, b is an integer of 1 to 3, and c is 0 or 1, and a + b + c = 4.)

  According to the present invention, as shown in the results of the examples, the pressure-sensitive adhesive composition containing a specific amount of a cross-linking agent and an imidazole silane compound in the (meth) acrylic polymer is cross-linked, whereby heat treatment or high-humidity treatment is performed. Therefore, the pressure-sensitive adhesive layer has excellent visibility and does not float or peel off.

  Note that the visibility in the present invention refers to the ease of reading a displayed image. When the visibility is deteriorated, it is difficult to read the displayed image, and therefore, it is not suitable for use in an optical member.

  Although the details of the reason why the pressure-sensitive adhesive composition exhibits such properties are not clear, by crosslinking a pressure-sensitive adhesive composition containing a specific amount of a crosslinking agent and an imidazole silane compound to the (meth) acrylic polymer, It is presumed that the pressure-sensitive adhesive layer is excellent in visibility and does not float or peel off due to heat treatment or high-humidity treatment.

The (meth) acrylic polymer in the present invention has a general formula CH ₂ ═C (R ^a ) COOR ^b (wherein R ^a is hydrogen or a methyl group, R ^b is an alkyl group having 2 to 14 carbon atoms) as a monomer unit. It is characterized by containing 30 to 98% by weight of (meth) acrylic monomer represented by the formula (1) and 0.1 to 30% by weight of other polymerizable monomers. By using such a polymer as the base polymer of the pressure-sensitive adhesive composition, it is possible to obtain a pressure-sensitive adhesive layer having a good balance between adhesiveness and durability.

  The (meth) acrylic polymer in the present invention refers to an acrylic polymer and / or a methacrylic polymer. The (meth) acrylate refers to acrylate and / or methacrylate.

  The pressure-sensitive adhesive composition of the present invention contains 0.02 to 5 parts by weight of a crosslinking agent with respect to 100 parts by weight of the (meth) acrylic polymer.

  Moreover, it is preferable that the said crosslinking agent contains at least 1 sort (s) chosen from the group which consists of an isocyanate type crosslinking agent, an epoxy type crosslinking agent, and a peroxide.

  The pressure-sensitive adhesive composition of the present invention contains 0.001 to 5 parts by weight of an imidazolesilane compound represented by the following formula (1) with respect to 100 parts by weight of the (meth) acrylic polymer. .

（ただし、上記式（１）において、Ｒ^１およびＲ^２は、水素原子または炭素数１〜６のアルキル基、Ｒ^３およびＲ^４は、炭素数１〜６のアルキル基、ならびにｎは１〜２０の整数である。また、ａは１〜３の整数、ｂは１〜３の整数、ならびにｃは０または１であり、かつａ＋ｂ＋ｃ＝４である。）

(In the above formula (1), R ¹ and R ² are hydrogen atoms or alkyl groups having 1 to 6 carbon atoms, R ³ and R ⁴ are alkyl groups having 1 to 6 carbon atoms, and n is 1 to 1) And a is an integer of 1 to 3, b is an integer of 1 to 3, and c is 0 or 1, and a + b + c = 4.)

  On the other hand, the pressure-sensitive adhesive layer of the present invention is obtained by crosslinking the pressure-sensitive adhesive composition described above. According to the pressure-sensitive adhesive layer of the present invention, since the pressure-sensitive adhesive composition having the above-described effects is crosslinked, the pressure-sensitive adhesive layer has excellent visibility and does not float or peel off due to heat treatment or high-humidity treatment. It becomes.

  In addition, the pressure-sensitive adhesive composition and pressure-sensitive adhesive layer of the present invention are particularly suitable for use as an optical member because they exhibit the above-described effects.

  On the other hand, the optical member with pressure-sensitive adhesive of the present invention is characterized in that the above-mentioned pressure-sensitive adhesive layer is formed on one side or both sides of the optical member. According to the optical member with pressure-sensitive adhesive of the present invention, the optical member with pressure-sensitive adhesive has excellent visibility and does not float or peel off due to heat treatment or high-humidity treatment because it has a pressure-sensitive adhesive layer that exhibits the above-described effects. It becomes.

  In addition, the image display device of the present invention is a liquid crystal display device, an organic EL display device, a PDP or the like using the optical member with an adhesive described above, and does not float or peel off due to heat treatment or high humidity treatment. It has a function that can exhibit excellent high durability.

  Hereinafter, embodiments of the present invention will be described in detail.

The pressure-sensitive adhesive composition of the present invention is
As a monomer unit, a (meth) acrylic group represented by the general formula CH ₂ = C (R ^a ) COOR ^b (where R ^a is hydrogen or a methyl group, and R ^b is an alkyl group having 2 to 14 carbon atoms) To 100 parts by weight of (meth) acrylic polymer containing 30 to 98% by weight of monomer and 0.1 to 30% by weight of other polymerizable monomer,
It contains 0.02 to 5 parts by weight of a crosslinking agent and 0.001 to 5 parts by weight of an imidazolesilane compound represented by the following formula (1).

In the present invention, the monomer unit is represented by the general formula CH ₂ ═C (R ^a ) COOR ^b (where R ^a is hydrogen or a methyl group, and R ^b is an alkyl group having 2 to 14 carbon atoms). A (meth) acrylic polymer containing 30 to 98% by weight of (meth) acrylic monomer and 0.1 to 30% by weight of other polymerizable monomer is used.

In the above general formula, R ^a is hydrogen or a methyl group. In the above general formula, R ^b is an alkyl group having 2 to 14 carbon atoms, preferably 3 to 12 carbon atoms, and more preferably 4 to 9 carbon atoms. The alkyl group of ^Rb can be either linear or branched, but is preferably branched because of its low glass transition point.

Specific examples of the (meth) acrylic monomer represented by the general formula CH ₂ ═C (R ^a ) COOR ^b include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, Isopropyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, 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 ( 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, phenoxyethyl (meth) acrylate, and the like. Of these, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and the like are preferably used.

In the present invention, the above-mentioned (meth) acrylic monomer represented by the general formula CH ₂ ═C (R ^a ) COOR ^b may be used alone or in combination of two or more. The content as a whole is 30 to 98% by weight, preferably 40 to 90% by weight, and more preferably 50 to 80% by weight in the whole monomer of the (meth) acrylic polymer. . If the amount of the (meth) acrylic monomer is too small, the adhesiveness is poor, which is not preferable.

  In the (meth) acrylic polymer of the present invention, as a monomer other than the above-mentioned monomers, the glass transition point of the (meth) acrylic polymer and a polymerizable monomer for adjusting the peelability are impaired. Can be used in a range that is not.

  Examples of other polymerizable monomers used in the (meth) acrylic polymer of the present invention include, for example, carboxyl group-containing monomers, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, cyano group-containing monomers, vinyl ester monomers, and aromatics. Adhesion of cohesive strength and heat resistance components such as vinyl monomers, acid anhydride group-containing monomers, hydroxyl group-containing monomers, amide group-containing monomers, amino group-containing monomers, imide group-containing monomers, epoxy group-containing monomers, vinyl ether monomers, etc. A component having a functional group that functions as a force-improving or crosslinking base, and a (meth) acrylic monomer having an alkyl group having 15 or more carbon atoms can be appropriately used. These monomer compounds may be used alone or in admixture of two or more.

  Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Of these, acrylic acid and methacrylic acid are particularly preferably used.

  Examples of the sulfonic acid group-containing monomer include styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, and (meth). Examples include acryloyloxynaphthalene sulfonic acid.

  Examples of the phosphate group-containing monomer include 2-hydroxyethyl acryloyl phosphate.

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

  Examples of the vinyl ester monomer include vinyl acetate, vinyl propionate, vinyl laurate, vinyl pyrrolidone and the like.

  Examples of the aromatic vinyl monomer include styrene, chlorostyrene, chloromethyl styrene, α-methyl styrene, and the like.

  Examples of the acid anhydride group-containing monomer include maleic anhydride and itaconic anhydride.

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl ( (Meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl acrylate, N-methylol (meth) acrylamide N-hydroxy (meth) acrylamide, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, etc. It is.

  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) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, dimethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate, diacetone (meth) ) Acrylamide, N-vinylacetamide, N, N′-methylenebis (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N-vinylcaprolactam, N-vinyl-2-pyrrolidone and the like.

  Examples of amino group-containing monomers include aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, and N- (meth) acryloylmorpholine. It is done.

  Examples of the imide group-containing monomer include N-cyclohexylmaleimide, N-phenylmaleimide, N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-hexylmaleimide, and itaconimide. Etc.

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

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

  Examples of the (meth) acrylic monomer having an alkyl group having 15 or more carbon atoms include pentadecyl (meth) acrylate and hexadecyl (meth) acrylate.

  The above-mentioned other polymerizable monomers may be used alone or in combination of two or more, but the total content of the other monomers in the (meth) acrylic polymer is 0.00. It is preferably 1 to 30% by weight, more preferably 0.3 to 25% by weight, and further preferably 0.5 to 20% by weight.

  The (meth) acrylic polymer used in the present invention preferably has a weight average molecular weight of 500,000 or more, more preferably 1,500,000 to 3,000,000. When the weight average molecular weight is less than 500,000, durability may be poor. On the other hand, from the viewpoint of workability, the weight average molecular weight is preferably 3 million or less. The weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene.

  In addition, the glass transition temperature (Tg) of the (meth) acrylic polymer is desirably −10 ° C. or lower, and preferably −20 ° C. or lower, for easy balance of the adhesive performance. When the glass transition temperature is higher than −10 ° C., the polymer is difficult to flow, and the adherend is insufficiently wetted, which may cause blisters generated between layers. In addition, the glass transition temperature (Tg) of a (meth) acrylic-type polymer can be adjusted in the said range by changing the monomer component and composition ratio to be used suitably.

  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 carried out under an inert gas stream such as nitrogen, as a polymerization initiator, for example, azobisisobutyronitrile 0.01 to 0.2 parts per 100 parts by weight of the total amount of monomers. Addition of parts by weight is usually performed at about 50 to 70 ° C. for about 8 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.

  Examples of the polymerization initiator used in the present invention 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, Ltd., VA-057), azo initiators, potassium persulfate, ammonium persulfate Persulfate such as di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate Di-sec-butylperoxydicarbonate, 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) peroxide such as cyclohexane, t-butyl hydroperoxide, hydrogen peroxide and other peroxide initiators, a combination of persulfate and sodium bisulfite, a combination of peroxide and sodium ascorbate Redox initiators that combine products and reducing agents Kill, but is not limited to these.

  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 the present invention, a chain transfer agent may be used in the polymerization. By using a chain transfer agent, the molecular weight of the (meth) acrylic polymer can be appropriately adjusted.

  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.

  These chain transfer agents may be used alone or in admixture of two or more, but the total content is 0.01-0. About 1 part by weight.

  Examples of the emulsifier used in emulsion polymerization include anionic emulsifiers such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzene sulfonate, 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.

  Furthermore, 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 with respect to 100 parts by weight of the monomer in view of polymerization stability and mechanical stability.

  The pressure-sensitive adhesive composition of the present invention is characterized by containing a crosslinking agent. Preferred crosslinking agents include isocyanate crosslinking agents, epoxy crosslinking agents, peroxides, and the like.

  The isocyanate-based crosslinking agent in the present invention is an isocyanate compound having in its molecule two or more isocyanate groups (including isocyanate-regenerating functional groups that are temporarily protected by blocking the isocyanate groups and quantifying them). Say.

  Moreover, the epoxy-type crosslinking agent in this invention means the epoxy compound which has a 2 or more epoxy group in 1 molecule.

  Moreover, as a peroxide in this invention, what can generate | occur | produce a radical by heating and can achieve bridge | crosslinking of a (meth) acrylic-type polymer can be especially used without a restriction | limiting.

  Examples of the isocyanate-based crosslinking agent include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate, alicyclic isocyanates such as isophorone diisocyanate, and aliphatic isocyanates such as hexamethylene diisocyanate.

  More specifically, for example, lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate, 2,4-tolylene diisocyanate, Aromatic diisocyanates such as 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate, polymethylene polyphenyl isocyanate, trimethylolpropane / tolylene diisocyanate trimer adduct (trade name Coronate L manufactured by Nippon Polyurethane Industry Co., Ltd.), tri Methylolpropane / hexamethylene diisocyanate trimer adduct (trade name Coronate HL, manufactured by Nippon Polyurethane Industry Co., Ltd.), hexamethylene dii Isocyanurate of cyanate (product name: Coronate HX, manufactured by Nippon Polyurethane Industry Co., Ltd.), polyether polyisocyanate, polyester polyisocyanate, and adducts of these with various polyols, isocyanurate bond, burette bond And polyisocyanates polyfunctionalized with allophanate bonds. These isocyanate-based crosslinking agents may be used alone or in combination of two or more.

  As the epoxy-based crosslinking agent, bisphenol A epichlorohydrin type epoxy-based resin, ethylene glycidyl ether, polyethylene glycol diglycidyl ether, glycerin glycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol glycidyl ether, trimethylolpropane glycidyl ether, Examples thereof include diglycidyl aniline, diamine glycidyl amine, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N′-diamine glycidylaminomethyl) cyclohexane and the like. These epoxy crosslinking agents may be used alone or in combination of two or more.

  Examples of the peroxide include di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate, and t-butylperoxyneodeca. Noate, t-hexylperoxypivalate, t-butylperoxypivalate, dilauroylperoxy, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxyisobutyrate And dibenzoyl peroxide. Among these, di (4-t-butylcyclohexyl) peroxydicarbonate, dilauroyl peroxide, and dibenzoyl peroxide, which are particularly excellent in crosslinking reaction efficiency, are preferably used. In consideration of productivity, the one-minute half-life temperature is preferably about 70 to 170 ° C, more preferably 90 to 150 ° C. If the half-life temperature for 1 minute is too low, a crosslinking reaction may occur during storage before applying the pressure-sensitive adhesive, and the viscosity of the coated product may increase, making the coating impossible. On the other hand, if the half-life temperature for 1 minute is too high, the temperature during the crosslinking reaction will increase and other side effects will occur, the desired properties will not be obtained due to insufficient decomposition, and the peroxide will remain so that crosslinking will occur over time. There are cases where the reaction proceeds, which is not preferable.

  The content of the crosslinking agent is preferably 0.02 to 5 parts by weight and more preferably 0.05 to 3 parts by weight with respect to 100 parts by weight of the (meth) acrylic polymer. preferable. If the amount is less than 0.02 parts by weight, the cohesive force may be insufficient. On the other hand, if the amount exceeds 2 parts by weight, the crosslinking may be excessively formed and the adhesiveness may be poor. In addition, the above-mentioned preferred crosslinking agents, such as isocyanate crosslinking agents, epoxy crosslinking agents, and peroxides, may be used alone or in admixture of two or more. The content of the agent as a whole should be within the above range. More preferably, each of them is used alone or in combination with an isocyanate crosslinking agent and a peroxide.

  In this invention, it is preferable to adjust the addition amount of a crosslinking agent so that the gel fraction of the bridge | crosslinked adhesive layer may be 20 to 95 weight%. When the gel fraction is less than 20% by weight, the cohesive force is lowered, so that the durability may be inferior. When it exceeds 95% by weight, the adhesiveness may be inferior.

The gel fraction of the pressure-sensitive adhesive composition in the present invention means that after the dry weight W ₁ (g) of the pressure-sensitive adhesive layer is immersed in ethyl acetate, the insoluble content of the pressure-sensitive adhesive layer is taken out from the ethyl acetate and dried. The weight W ₂ (g) was measured, and the value calculated as (W ₂ / W ₁ ) × 100 was taken as the gel fraction (% by weight).

More specifically, for example, W ₁ (g) (about 500 mg) was collected from the pressure-sensitive adhesive layer after crosslinking. Next, the pressure-sensitive adhesive layer was immersed in ethyl acetate at about 23 ° C. for 7 days, and then the pressure-sensitive adhesive layer was taken out and dried at 130 ° C. for 2 hours. W ₂ (g) of the obtained pressure-sensitive adhesive layer Was measured. By applying W ₁ and W ₂ to the above formula, the gel fraction (% by weight) was determined.

  Furthermore, the pressure-sensitive adhesive composition of the present invention is characterized by containing an imidazolesilane compound.

  As the imidazole silane compound in the present invention, an imidazole silane compound represented by the following formula (1) is used.

（ただし、上記式（１）において、Ｒ^１およびＲ^２は、水素原子または炭素数１〜６のアルキル基、Ｒ^３およびＲ^４は、炭素数１〜６のアルキル基、ならびにｎは１〜２０の整数である。また、ａは１〜３の整数、ｂは１〜３の整数、ならびにｃは０または１であり、かつａ＋ｂ＋ｃ＝４である。）

(In the above formula (1), R ¹ and R ² are hydrogen atoms or alkyl groups having 1 to 6 carbon atoms, R ³ and R ⁴ are alkyl groups having 1 to 6 carbon atoms, and n is 1 to 1) And a is an integer of 1 to 3, b is an integer of 1 to 3, and c is 0 or 1, and a + b + c = 4.)

In the imidazole silane compound, R ¹ and R ² are a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, preferably a hydrogen atom, a methyl group, or an ethyl group, and more preferably a hydrogen atom. preferable.

In the imidazole silane compound, R ³ and R ⁴ are each an alkyl group having 1 to 6 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group or an ethyl group. .

  In the imidazole silane compound, n is an integer of 1 to 20, preferably 1 to 6, and more preferably 2 to 4.

  In the imidazole silane compound, a is an integer of 1 to 3, b is an integer of 1 to 3, and c is 0 or 1, and a + b + c = 4, but a = 1 is preferable.

  Among these, for example, imidazole silane compounds represented by the following formulas (2) and (3) are preferable for the use of the present invention.

  The imidazole silane compound may be used alone or as a mixture of two or more thereof, but the total content is 100 parts by weight of the (meth) acrylic polymer. It is preferable to contain 0.001-5 weight part of silane compounds, and it is more preferable to contain 0.01-2 weight part. If it is less than 0.001 part by weight, the durability may be inferior. On the other hand, if it exceeds 5 parts by weight, the adhesive force to an optical member (adhered body) such as a liquid crystal cell may increase excessively.

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

  The pressure-sensitive adhesive composition of the present invention has the above-described configuration.

  On the other hand, the pressure-sensitive adhesive layer of the present invention is formed by crosslinking the pressure-sensitive adhesive composition as described above. At that time, the pressure-sensitive adhesive composition is generally crosslinked after application of the pressure-sensitive adhesive composition, but it is also possible to transfer the pressure-sensitive adhesive layer comprising the crosslinked pressure-sensitive adhesive composition to a support or the like. is there.

  The method of forming the pressure-sensitive adhesive layer on the support (optical member, separator, etc.) is not particularly limited. For example, the pressure-sensitive adhesive composition is applied to a release-treated separator and the like, and the polymerization solvent is dried and removed. The adhesive layer is prepared by a method of transferring the adhesive layer to a support, or a method of applying the adhesive composition to the support and drying and removing the polymerization solvent to form the adhesive layer on the support. In addition, when producing an optical member with a pressure-sensitive adhesive by applying the pressure-sensitive adhesive composition on a support, one or more solvents other than the polymerization solvent are contained in the composition so that the composition can be uniformly coated on the support. (Solvent) may be newly added.

  Examples of the support used in the present invention include plastic substrates such as polyethylene terephthalate (PET) and polyester film, porous materials such as paper and nonwoven fabric, and optical members.

  The plastic substrate is not particularly limited as long as it can be formed into a sheet shape or a film shape. For example, polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene Polyolefin films such as propylene copolymer, ethylene / 1-butene copolymer, ethylene / vinyl acetate copolymer, ethylene / ethyl acrylate copolymer, ethylene / vinyl alcohol copolymer, polyethylene terephthalate, polyethylene naphthalate, poly Polyester film such as butylene terephthalate, polyacrylate film, polystyrene film, nylon 6, nylon 6,6, polyamide film such as partially aromatic polyamide, polyvinyl chloride film, polyvinylidene chloride film, polycarbonate Such as ball titanate film, and the like. The thickness of the film is usually about 4 to 100 μm, preferably about 4 to 25 μm.

  For plastic substrates, if necessary, silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based mold release agents, mold release with silica powder, etc., acid treatment, acid treatment, alkali treatment, primer treatment, Anti-adhesive treatment such as corona treatment, plasma treatment and ultraviolet treatment, coating type, kneading type, vapor deposition type and the like can also be carried out.

  Examples of the solvent used in the present invention include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexanone, n-hexane, toluene, xylene, methanol, ethanol, n-propanol, isopropanol, water and the like. . These solvents may be used alone or in combination of two or more.

  Moreover, as a formation method of the adhesive layer of this invention, the well-known method used for manufacture of adhesive sheets is used. Specifically, for example, by 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.

  In addition, for example, a step of forming a layer made of the pressure-sensitive adhesive composition described above on one side or both sides on a support (optical member, separator, etc.) and a layer made of the pressure-sensitive adhesive composition are peroxidized. The pressure-sensitive adhesive layer of the present invention can be obtained by using a production method including a step of subjecting a product to crosslinking. By using such a production method, the above-mentioned excellent adhesive properties, in particular, even when the adhesive layer is thinned, an adhesive having excellent durability that does not float or peel off due to heat treatment or high-humidity treatment. An agent layer can be obtained.

  The surface of the pressure-sensitive adhesive layer may be subjected to easy attachment treatment such as corona treatment or plasma treatment.

  Further, when the pressure-sensitive adhesive is exposed on such a surface, the pressure-sensitive adhesive layer may be protected with a sheet (separator) subjected to a release treatment until it is practically used.

  As a constituent material of the separator, for example, a plastic film such as polyethylene, polypropylene, polyethylene terephthalate, and a polyester film, a porous material such as paper, cloth, and nonwoven fabric, a net, a foamed sheet, a metal foil, and a laminate thereof, as appropriate. 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 the above production method, the release-treated sheet can be used as it is as a separator such as an adhesive sheet or an optical member with an adhesive, and the process can be simplified.

  When the pressure-sensitive adhesive layer in the present invention is stored for a long time under high-temperature and high-humidity conditions such as 110 ° C. and 70 ° C./95% RH after crosslinking, the above-mentioned pressure-sensitive adhesive composition is crosslinked with the above-mentioned crosslinking agent. Even so, the pressure-sensitive adhesive layer is excellent in visibility and does not float or peel off.

  Moreover, in the said adhesive layer, it is preferable that the thickness of the said adhesive layer is 1-500 micrometers, It is more preferable that it is 1-100 micrometers, It is further more preferable that it is 1-50 micrometers.

  Furthermore, the pressure-sensitive adhesive composition and pressure-sensitive adhesive layer of the present invention are particularly suitable for use as an optical member because they exhibit the above-described effects.

  Moreover, the optical member with an adhesive of this invention forms the adhesive layer which has said structure on the single side | surface or both surfaces of an optical member (optical film). Since the optical member with pressure-sensitive adhesive of the present invention includes a pressure-sensitive adhesive layer that exhibits the above-described effects, even when stored for a long time under high-temperature and high-humidity conditions such as 110 ° C. and 70 ° C./95% RH , It does not float or peel off and has excellent visibility.

  As the optical member, those used for forming an image display device such as a liquid crystal display device are used, and the type thereof is not particularly limited. For example, a polarizing plate etc. are mention | raise | lifted as an optical member (optical film). As the polarizing plate, one having a transparent protective film on one side 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 hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films, and two colors such as iodine and dichroic dyes. Examples include polyene-based oriented films such as those obtained by adsorbing volatile 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 produced, for example, by dyeing 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 and 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 in an aqueous solution of boric acid or potassium iodide or in a water bath.

  As a material for forming the transparent protective film provided on one side or both sides of the polarizer, a material excellent in transparency, mechanical strength, thermal stability, moisture shielding property, isotropy and the like is preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, styrene such as polystyrene and acrylonitrile / styrene copolymer (AS resin) -Based polymer, polycarbonate-based polymer and the like. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above Polymer blends and the like are also examples of polymers that form the transparent protective film. The transparent protective film can also be formed as a cured layer of thermosetting or ultraviolet curable resin such as acrylic, urethane, acrylurethane, epoxy, and silicone.

  Moreover, the polymer film described in JP-A-2001-343529 (WO01 / 37007), for example, (A) a thermoplastic resin having a substituted and / or unsubstituted imide group in the side chain, and (B) a substitution in the side chain And / or a resin composition containing an unsubstituted phenyl and a thermoplastic resin having a nitrile group. 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.

  Although the thickness of a 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.

  Moreover, it is preferable that a protective film has as little color as possible. Therefore, Rth = (nx−nz) · d (where nx is the refractive index in the slow axis direction in the film plane, nz is the refractive index in the film thickness direction, and d is the film thickness). A protective film having a 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 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.

  As the protective film, a cellulose polymer such as triacetyl cellulose is preferable from the viewpoints of polarization characteristics and durability. A triacetyl cellulose film is particularly preferable. In addition, when providing a protective film in the 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. The polarizer and the protective film are usually in close contact with each other through an aqueous adhesive or the like. Examples of the water-based adhesive include an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, a vinyl-based latex, a water-based polyurethane, and a water-based polyester.

  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.

  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. with an appropriate ultraviolet curable resin such as acrylic or silicone 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. Further, the anti-sticking treatment is performed for the purpose of preventing adhesion with an adjacent layer.

  Anti-glare treatment is applied for the purpose of preventing the external 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 sandblasting or embossing. 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. The fine particles to be included in the formation of the surface fine concavo-convex structure are, for example, conductive composed of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide or the like having an average particle size of 0.5 to 50 μm. Transparent fine particles such as inorganic fine particles and organic fine particles made of a crosslinked or uncrosslinked polymer may be used. When forming a surface fine uneven structure, the amount of fine particles used is generally about 2 to 50 parts by weight, preferably 5 to 25 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.

  In addition, examples of the optical member of the present invention include a liquid crystal display device such as a reflection plate, a semi-transmission plate, a retardation plate (including wavelength plates such as 1/2 and 1/4), a viewing angle compensation film, and a brightness enhancement film. What becomes an optical layer which may be used for the formation of is mentioned. These can be used alone as the optical member of the present invention, and can be laminated on the polarizing plate for practical use and used in one or more layers.

  In particular, a reflective polarizing plate or 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 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 viewing angle compensation film is further laminated on a plate, or a polarizing plate in which a brightness 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). Thus, there is an advantage that it is easy to reduce the thickness of the liquid crystal display device. 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, if 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. Moreover, the transparent protective film contains fine particles so as to have 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 transparent 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 can be formed by, for example, depositing metal by an appropriate method such as a vapor deposition method such as a vacuum vapor deposition method, an ion plating method, a sputtering method, or a plating method. It can be performed by a method of directly attaching to the surface of the transparent protective layer.

  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, etc. prevents the decrease in reflectance due to oxidation, and thus the long-term sustainability of the initial reflectance. In addition, it is more preferable to avoid a separate attachment of the protective layer.

  The transflective polarizing plate can be obtained by using a transflective 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 or the like that displays an image using a built-in light 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 save the energy of using a light source such as a backlight in a bright atmosphere, and is useful for forming a liquid crystal display device that can be used with a built-in light source 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 the image is displayed in color, and also has an antireflection function.

  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, polyvinyl alcohol, polyamide, polyimide, polyolefin, polyvinyl chloride, cellulose polymer, norbornene resin, or binary, ternary various copolymers, graft copolymers Examples thereof include polymers and blends. These polymer materials become oriented products (stretched films) by stretching or the like.

  Examples of the liquid crystalline 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. It is done. Specific examples of main-chain liquid crystalline polymers include nematic-oriented polyester-based liquid crystalline polymers, discotic polymers, and cholesteric polymers that have a structure in which a mesogenic group is bonded to a spacer portion that imparts flexibility. It is done. Specific examples of the side chain type liquid crystalline polymer include polysiloxane, polyacrylate, polymethacrylate, or polymalonate as a main chain skeleton, and a nematic alignment imparting paraffin through a spacer portion composed of a conjugated atomic group as a side chain. Examples thereof include those having a mesogen moiety composed of a substituted cyclic compound unit. These liquid crystalline polymers can be obtained by, for example, applying a solution of a liquid crystalline polymer on an alignment surface such as one obtained by rubbing the surface of a thin film such as polyimide or polyvinyl alcohol formed on a glass plate or one obtained by obliquely depositing 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 for the purpose of compensating for coloring or viewing angle due to birefringence of various wavelength plates and liquid crystal layers, for example. In this case, the retardation plate may be laminated to control optical characteristics such as retardation.

  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 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 (reflection type) polarizing plate and a retardation plate. An optical member such as an elliptically polarizing plate is advantageous in that it is excellent in quality stability, laminating workability, etc., and can improve the manufacturing efficiency of a liquid crystal display device or the like.

  The viewing angle compensation film is a film for widening the viewing angle so that an 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 viewing angle compensation phase difference plate include a phase difference plate, an alignment film such as a liquid crystal polymer, and a support 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 uniaxially stretched in the plane direction, whereas a retardation plate used as a viewing angle compensation film stretches biaxially 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 tilted 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, or a film obtained by obliquely aligning a liquid crystal polymer. Can be given. 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.

  Also, from the viewpoint of achieving a wide viewing angle with good visibility, an optically compensated phase difference in which a liquid crystal polymer alignment layer, in particular an optically anisotropic layer composed of a discotic liquid crystal polymer gradient alignment layer, is supported by a triacetylcellulose film. A 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 provided on the rear side thereof, and re-incident on the brightness enhancement film, and part or all of the light is transmitted as light in a predetermined polarization state. The brightness can be improved by increasing the amount of light transmitted through the improvement film and increasing the amount of light that can be used for liquid crystal display image display by supplying polarized light that is difficult to absorb into the polarizer. is there. 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 is reduced, resulting in a dark image. In the brightness enhancement film, light having a polarization direction that is absorbed by the polarizer is reflected once by the brightness enhancement film without being incident on the polarizer, and further inverted through a reflective layer provided on the rear side thereof. Repeatedly re-enter the brightness enhancement film, and the brightness enhancement film transmits only polarized light whose polarization direction is such that the polarization direction of light reflected and inverted between the two can pass through the polarizer. Therefore, 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 diffuser plate returns the polarized light to the original natural light state. The light in the non-polarized state, that is, the natural light state is directed to the reflection layer and the like, reflected through the reflection layer and the like, and again passes through the diffusion plate and reenters the brightness enhancement film. Thus, while maintaining the brightness of the display screen by providing a diffuser plate that returns polarized light to the original natural light state between the brightness enhancement film and the reflective layer, etc., at the same time, the unevenness of the brightness of the display screen is reduced, A uniform and bright screen can be provided. 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.

  As the brightness enhancement film, for example, a dielectric multilayer thin film or a multilayer laminate of thin film films having different refractive index anisotropy, such as a characteristic that transmits linearly polarized light having a predetermined polarization axis and reflects other light. Such as a cholesteric liquid crystal polymer alignment film or a film substrate whose alignment liquid crystal layer is supported on a film substrate, which reflects either left-handed or right-handed circularly polarized light and transmits other light. Appropriate ones such as those shown 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 directly incident on the polarizing plate with the polarization axis aligned, 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 emits circularly polarized light such as a cholesteric liquid crystal layer, it can be directly incident on a polarizer, 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 in a wide wavelength range such as a visible light region has, for example, a retardation layer that functions as a quarter-wave plate for light-color light with a wavelength of 550 nm and other retardation characteristics. The phase difference layer shown, for example, the phase difference layer which functions as a half-wave plate, etc. can be obtained by the method of superimposing. 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 that has a reflection wavelength different from each other and has an arrangement structure in which two layers or three or more layers are overlapped to obtain a layer that reflects circularly polarized light in a wide wavelength range such as a visible light region. 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 three or more optical layers like 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-mentioned reflective polarizing plate or semi-transmissive polarizing plate and a retardation plate are combined may be used.

  The optical member in which the optical layer is laminated on the 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 the liquid crystal display device and the like can be improved because of excellent stability and assembly work. For the lamination, an appropriate adhesive means such as a pressure-sensitive 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 phase difference characteristic.

  In addition, in each layer such as an optical member and an adhesive layer of the optical member with an adhesive of the present invention, for example, a salicylic acid ester compound, a benzophenol compound, a benzotriazole compound, a cyanoacrylate compound, a nickel complex compound, etc. It may be one having a UV absorbing ability by a method such as a method of treating with a UV absorber.

  The optical member with an adhesive of the present invention can be preferably used for forming various image display devices such as a liquid crystal display device. 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 optical member with an adhesive, and an illumination system as necessary, and incorporating a drive circuit. There is no limitation in particular except the point which uses the optical member by this invention, It can apply to the former. As the liquid crystal cell, for example, an arbitrary type such as a TN type, an STN type, or a π type can be used.

  Appropriate liquid crystal display devices such as a liquid crystal display device in which an optical member with an adhesive is disposed on one side or both sides of a liquid crystal cell, and a backlight or reflector used in an illumination system can be formed. In that case, the optical member by this invention can be installed in the one side or both sides of a liquid crystal cell. When optical members 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 of appropriate parts such as a diffuser plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffuser plate, and a backlight at an appropriate position. Alternatively, two or more layers can be arranged.

  Next, an organic electroluminescence device (organic EL display device) will be described. 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 or the like and a light emitting layer made of a fluorescent organic solid such as anthracene, Or a combination of such a light emitting layer and an electron injection layer composed of a perylene derivative, or a combination of these hole injection layer, light emitting layer, and electron injection layer. Are known.

  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.

  In order to improve the anchoring force when such an optical member is bonded to the above-mentioned pressure-sensitive adhesive layer, the surface of the optical member may be subjected to easy attachment treatment such as corona treatment or plasma treatment, or undercoating treatment.

  Further, the image display device of the present invention is a liquid crystal display device, an organic EL display device, a PDP or the like using the above-mentioned optical member with an adhesive, and even when the adhesive layer is thinned, it is 110 ° C. Even when stored for a long time under high-temperature and high-humidity conditions such as 70 ° C./95% RH, it has a function with excellent visibility that does not cause floating or peeling.

  Examples and the like specifically showing the configuration and effects of the present invention will be described below. In addition, the evaluation item in an Example etc. measured as follows.

<Measurement of molecular weight>
The weight average molecular weight of the obtained (meth) acrylic polymer was measured by GPC (gel permeation chromatography).
・ Analyzer: HLC-8120GPC manufactured by Tosoh Corporation
-Data processing device: GPC-8020 manufactured by Tosoh Corporation
Column: manufactured by Tosoh Corporation, G7000H _XL -H + GMH _XL + GMH _XL
Column size: 7.8mmφ x 30cm each (total 90cm)
・ Flow rate: 0.8ml / min
Injection sample concentration: about 0.1% by weight
・ Injection volume: 100 μl
-Column temperature: 40 ° C
・ Eluent: Tetrahydrofuran ・ Detector: Differential refractometer (RI)
The molecular weight was calculated in terms of polystyrene.

<Measurement of gel fraction>
W ₁ g (about 0.1 g) of the pressure-sensitive adhesive layer prepared in each Example / Comparative Example was taken out and immersed in ethyl acetate at room temperature (about 25 ° C.) for 1 week. Thereafter, the pressure-sensitive adhesive layer (insoluble matter) subjected to the immersion treatment was taken out from ethyl acetate, and the weight W ₂ g after drying at 130 ° C. for 2 hours was measured, and the value calculated as (W ₂ / W ₁ ) × 100 was obtained. The gel fraction (% by weight) was used.

<Measurement of adhesive strength>
(Initial adhesive strength)
The optical film with pressure-sensitive adhesive (25 mm × 100 mm) obtained in Examples and Comparative Examples was attached to a non-alkali glass (Corning Corp., 1737, thickness: 0.7 mm) by reciprocating 1 roll with a 2 kg roller, An evaluation sample was obtained. Thereafter, in a 25 ° C./65% RH atmosphere, the peel adhesion (initial adhesion to glass) (N / 25 mm) was measured at a peel angle of 90 ° and a peel speed of 300 mm / min.

(Adhesive strength after 70 ° C hot water test)
A sample similar to the above sample for evaluating the initial adhesive strength was left in a 70 ° C. water bath for 1 hour, then removed from the water bath, wiped with water droplets on the surface of the sample, and peeled at 90 ° in a 25 ° C./65% RH atmosphere. The peel adhesive strength (N / 25 mm) was measured at a peel speed of 300 mm / min.

<Durability evaluation>
(Durability test (a))
The prepared optical film with pressure-sensitive adhesive (15-inch size) was attached to non-acrylic glass (Corning Corp., 1737, thickness: 0.7 mm), and then subjected to 15 at an autoclave at 50 ° C. and 5 atm (0.5 MPa). The sample was stored for 500 minutes in an atmosphere of 110 ° C. (dry) for 100 minutes and then returned to room temperature (about 25 ° C.) to obtain a sample for evaluation. The durability test (a) (heat treatment test) is evaluated visually, and the evaluation criteria are as follows. In addition, as visibility, the presence or absence of floating and peeling and the visibility of a display image were evaluated.
・ If the adhesive layer does not lift or peel: ○
・ If the adhesive layer was lifted or peeled off but did not affect the visibility: ×
・ If the adhesive layer is lifted or peeled off and affects visibility: XX

<Durability evaluation>
(Durability test (b))
The prepared optical film with pressure-sensitive adhesive (15-inch size) was attached to acrylic-free glass (Corning Corp., 1737, thickness: 0.7 mm), and then subjected to 15 at an autoclave at 50 ° C. and 5 atm (0.5 Pa). The sample was stored for 500 minutes under an atmosphere of 70/95% RH for 5 minutes and then returned to room temperature (about 25 ° C.) to obtain a sample for evaluation. The durability test (b) (heated humidification test) is evaluated visually, and the evaluation criteria are as follows. In addition, as visibility, the presence or absence of floating and peeling and the visibility of a display image were evaluated.
・ If the adhesive layer does not lift or peel: ○
・ If the adhesive layer was lifted or peeled off but did not affect the visibility: ×
・ If the adhesive layer is lifted or peeled off and affects visibility: XX

<Preparation of (meth) acrylic polymer>
[Acrylic polymer (A)]
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube and a condenser, 85 parts by weight of butyl acrylate, 15 parts by weight of acrylic acid, 0.2 part by weight of benzoyl peroxide as a polymerization initiator, 200 ethyl acetate After charging parts by weight and introducing nitrogen gas with gentle stirring to replace the nitrogen, a polymerization reaction was carried out for 8 hours while maintaining the liquid temperature in the flask at around 60 ° C. to prepare an acrylic polymer (A) solution. . The acrylic polymer (A) had a weight average molecular weight of 1,900,000.

[Acrylic polymer (B)]
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube and a condenser, 85 parts by weight of butyl acrylate, 15 parts by weight of N-cyclohexylmaleimide, 0.2 part by weight of benzoyl peroxide as a polymerization initiator, acetic acid After charging 200 parts by weight of ethyl 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. and a polymerization reaction was carried out for 8 hours to obtain an acrylic polymer (B) solution. Prepared. The acrylic polymer (B) had a weight average molecular weight of 1.85 million.

[Acrylic polymer (C)]
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 85 parts by weight of butyl acrylate, 15 parts by weight of N, N-dimethylacrylamide, and 0.2 parts by weight of benzoyl peroxide as a polymerization initiator After adding 200 parts by weight of ethyl acetate and introducing nitrogen gas with gentle stirring to replace the nitrogen, a polymerization reaction is carried out for 8 hours while keeping the liquid temperature in the flask at around 60 ° C., and acrylic polymer (C) A solution was prepared. The acrylic polymer (C) had a weight average molecular weight of 1,700,000.

<Preparation of polarizing plate>
A polyvinyl alcohol film (thickness: 80 μm) was stretched 5 times in an aqueous iodine solution and then dried. Subsequently, a triacetyl cellulose film (thickness: 80 μm) was bonded to both sides of the film via an adhesive (manufactured by Nippon Synthetic Chemical Co., Ltd., Gohsenol NH-18) to prepare a polarizing plate.

[Example 1]
(Preparation of optical film with adhesive)
0.5 parts by weight of an isocyanate crosslinking agent (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate L) and imidazole silane represented by the following formula (2) with respect to 100 parts by weight of the solid content of the acrylic polymer (A) solution An acrylic pressure-sensitive adhesive solution (1) containing 0.1 part by weight of the compound was prepared.

  Next, the acrylic pressure-sensitive adhesive solution (1) is applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm) and dried at 150 ° C. for 3 minutes. And a pressure-sensitive adhesive layer having a thickness of 20 μm after drying was formed. In addition, the gel fraction of the adhesive layer at this time was 81 weight%. The pressure-sensitive adhesive layer was bonded to the polarizing plate to produce an optical film with a pressure-sensitive adhesive.

[Example 2]
(Preparation of optical film with adhesive)
In Example 1, it replaced with the said imidazole silane compound, and performed similarly except having used 0.1 weight part of imidazole silane compounds represented by following formula (3), and prepared the acrylic adhesive solution (2). .

  Next, the acrylic pressure-sensitive adhesive solution (2) was applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm) and dried at 150 ° C. for 3 minutes. And a pressure-sensitive adhesive layer having a thickness of 20 μm after drying was formed. In addition, the gel fraction of the adhesive layer at this time was 81 weight%. The pressure-sensitive adhesive layer was bonded to the polarizing plate to produce an optical film with a pressure-sensitive adhesive.

Example 3
(Preparation of optical film with adhesive)
In Example 1, it carried out similarly except having used the said imidazole silane compound 0.5 weight part, and prepared the acrylic adhesive solution (3).

  Next, the acrylic pressure-sensitive adhesive solution (3) is applied to one side of a polyethylene-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm) and dried at 150 ° C. for 3 minutes. And a pressure-sensitive adhesive layer having a thickness of 20 μm after drying was formed. In addition, the gel fraction of the adhesive layer at this time was 81 weight%. The pressure-sensitive adhesive layer was bonded to the polarizing plate to produce an optical film with a pressure-sensitive adhesive.

Example 4
(Preparation of optical film with adhesive)
In Example 1, it replaced with the said acrylic polymer (A), and performed similarly except having used the said acrylic polymer (B), and prepared the acrylic adhesive solution (4).

  Next, the acrylic pressure-sensitive adhesive solution (4) was applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm) and dried at 150 ° C. for 3 minutes. And a pressure-sensitive adhesive layer having a thickness of 20 μm after drying was formed. In addition, the gel fraction of the adhesive layer at this time was 75 weight%. The pressure-sensitive adhesive layer was bonded to the polarizing plate to produce an optical film with a pressure-sensitive adhesive.

Example 5
(Preparation of optical film with adhesive)
In Example 1, it replaced with the said acrylic polymer (A), and carried out similarly except having used the said acrylic polymer (C), and prepared the acrylic adhesive solution (5).

  Next, the acrylic pressure-sensitive adhesive solution (5) was applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm) and dried at 150 ° C. for 3 minutes. And a pressure-sensitive adhesive layer having a thickness of 20 μm after drying was formed. In addition, the gel fraction of the adhesive layer at this time was 76 weight%. The pressure-sensitive adhesive layer was bonded to the polarizing plate to produce an optical film with a pressure-sensitive adhesive.

Example 6
(Preparation of optical film with adhesive)
In Example 1, it carried out similarly except having changed the usage-amount of the imidazole silane compound represented by the said Formula (2) into 0.1 weight part, and produced the optical film with an adhesive.

Example 7
(Preparation of optical film with adhesive)
In Example 1, it carried out similarly except having changed the usage-amount of the imidazole silane compound represented by the said Formula (2) into 4 weight part, and produced the optical film with an adhesive.

Example 8
(Preparation of optical film with adhesive)
In Example 1, it carried out similarly except having used the epoxy type crosslinking agent (Mitsubishi Gas Chemical, TETRAD-C) instead of the isocyanate type crosslinking agent, and produced the optical film with an adhesive.

[Comparative Example 1]
(Preparation of optical film with adhesive)
An acrylic pressure-sensitive adhesive solution (6) was prepared in the same manner as in Example 1 except that the imidazolesilane compound was not used.

  Next, the acrylic pressure-sensitive adhesive solution (6) was applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm) and dried at 150 ° C. for 3 minutes. And a pressure-sensitive adhesive layer having a thickness of 20 μm after drying was formed. In addition, the gel fraction of the adhesive layer at this time was 81 weight%. The pressure-sensitive adhesive layer was bonded to the polarizing plate to produce an optical film with a pressure-sensitive adhesive.

[Comparative Example 2]
(Preparation of optical film with adhesive)
In Example 1, it replaced with the said imidazole silane compound and carried out similarly except having used 0.1 weight part of epoxy silane compounds represented by following formula (4), and prepared the acrylic adhesive solution (7). .

  Next, the acrylic pressure-sensitive adhesive solution (7) was applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm) and dried at 150 ° C. for 3 minutes. And a pressure-sensitive adhesive layer having a thickness of 20 μm after drying was formed. In addition, the gel fraction of the adhesive layer at this time was 81 weight%. The pressure-sensitive adhesive layer was bonded to the polarizing plate to produce an optical film with a pressure-sensitive adhesive.

[Comparative Example 3]
(Preparation of optical film with adhesive)
In Example 1, it replaced with the said imidazole silane compound, and performed similarly except having used 0.1 weight part of (meth) acrylic acid ester represented by following formula (5), and acrylic adhesive solution (8) Adjusted.

  Next, the acrylic pressure-sensitive adhesive solution (8) was applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm) and dried at 150 ° C. for 3 minutes. And a pressure-sensitive adhesive layer having a thickness of 20 μm after drying was formed. In addition, the gel fraction of the adhesive layer at this time was 81 weight%. The pressure-sensitive adhesive layer was bonded to the polarizing plate to produce an optical film with a pressure-sensitive adhesive.

[Comparative Example 4]
(Preparation of optical film with adhesive)
In Example 1, it replaced with the said imidazole silane compound, and it carried out similarly except having used 0.1 weight part of silane compounds which have the beta ketoester structure represented by following formula (6), and acrylic adhesive solution (9 ) Was adjusted.

  Next, the acrylic pressure-sensitive adhesive solution (9) is applied to one side of a polyethylene-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm) and dried at 150 ° C. for 3 minutes. And a pressure-sensitive adhesive layer having a thickness of 20 μm after drying was formed. In addition, the gel fraction of the adhesive layer at this time was 81 weight%. The pressure-sensitive adhesive layer was bonded to the polarizing plate to produce an optical film with a pressure-sensitive adhesive.

[Comparative Example 5]
(Preparation of optical film with adhesive)
In Example 1, the acrylic polymer (C) was used instead of the acrylic polymer (A), and the β-ketoester structure represented by the formula (6) was used instead of the imidazole silane compound. An acrylic pressure-sensitive adhesive solution (10) was prepared in the same manner except that 0.1 part by weight of a silane compound having a viscosity was used.

  Next, the acrylic pressure-sensitive adhesive solution (10) was applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm) and dried at 150 ° C. for 3 minutes. And a pressure-sensitive adhesive layer having a thickness of 20 μm after drying was formed. In addition, the gel fraction of the adhesive layer at this time was 76 weight%. The pressure-sensitive adhesive layer was bonded to the polarizing plate to produce an optical film with a pressure-sensitive adhesive.

  According to the above method, the adhesive strength of the produced optical film with pressure-sensitive adhesive was measured (initially and after the hot water test), and durability was evaluated (durability test (a, b)). The obtained results are shown in Table 1.

  From the results of Table 1 above, when the optical film with pressure-sensitive adhesive prepared according to the present invention was used (Examples 1 to 5), in any of the examples, the adhesive force was excellent, and long-term storage was performed under high temperature and high humidity conditions. Even if it is a case, it turns out that a float and peeling do not arise and it is excellent in visibility.

  On the other hand, when using a laminated sample that does not satisfy the configuration of the present invention (Comparative Examples 1 to 5), in any comparative example, when stored for a long time under high temperature and high humidity conditions, As a result, the visibility cannot be arranged side by side, and it became clear that the durability is inferior compared with the case where the pressure-sensitive adhesive layer of the present invention is used.

  As described above, the pressure-sensitive adhesive layer of the present invention has excellent visibility and does not float or peel even when stored for a long time under high temperature and high humidity conditions such as 110 ° C. and 70 ° C./95% RH. It turns out that it is.

Claims (7)

As a monomer unit, a (meth) acrylic group represented by the general formula CH ₂ = C (R ^a ) COOR ^b (where R ^a is hydrogen or a methyl group, and R ^b is an alkyl group having 2 to 14 carbon atoms) To 100 parts by weight of (meth) acrylic polymer containing 30 to 98% by weight of monomer and 0.1 to 30% by weight of other polymerizable monomer,
A pressure-sensitive adhesive composition comprising 0.02 to 5 parts by weight of a crosslinking agent and 0.001 to 5 parts by weight of an imidazolesilane compound represented by the following formula (1).

(In the above formula (1), R ¹ and R ² are hydrogen atoms or alkyl groups having 1 to 6 carbon atoms, R ³ and R ⁴ are alkyl groups having 1 to 6 carbon atoms, and n is 1 to 1) And a is an integer of 1 to 3, b is an integer of 1 to 3, and c is 0 or 1, and a + b + c = 4.)   The pressure-sensitive adhesive composition according to claim 1, wherein the crosslinking agent contains at least one selected from the group consisting of an isocyanate crosslinking agent, an epoxy crosslinking agent, and a peroxide.   The pressure-sensitive adhesive composition according to claim 1 or 2, which is used for an optical member.   A pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition according to claim 1.   The pressure-sensitive adhesive layer according to claim 4, which is used for an optical member.   6. An optical member with a pressure-sensitive adhesive comprising the pressure-sensitive adhesive layer according to claim 4 formed on one side or both sides of an optical member.   An image display device using at least one optical member with an adhesive according to claim 6.