JP5443696B2 - Adhesive composition, adhesive layer and method for producing the same, and optical member with adhesive - Google Patents

Description

  The present invention relates to a method for graft polymerization of a (meth) acrylic polymer and a method for producing a (meth) acrylic polymer. Moreover, this invention relates to the adhesive composition using the said (meth) acrylic-type polymer. Moreover, this invention relates to the adhesive layer formed with the said adhesive composition, and its manufacturing method. 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, a microlens sheet, a light diffusion 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, a PDP, various backlights, and an illumination light source.

  As a means for modifying various polymers, graft polymerization soot that imparts the properties of a branch polymer while maintaining the properties of a trunk polymer has been used for a long time. Specifically, for example, a polymerization method in the presence of polymerizing a monomer that becomes a branch polymer in the presence of a trunk polymer, or a double bond is introduced at the terminal of a polymer that becomes a branch, and polymerization is performed together during the polymerization of the trunk polymer. The macromonomer method, a polymer reaction method in which a functional group is introduced at the end of a polymer to be branched and reacted with a trunk polymer to be grafted are exemplified. Among these, a method of introducing a peroxide structure as an initiation point into the side chain of the trunk polymer is also used, but the polymerization reaction is performed by adding an initiator and a monomer in the presence of the trunk polymer, A polymerization method in the presence of generating radicals by extracting hydrogen from a trunk polymer and polymerizing a branch polymer starting from the radical has been widely performed because of its simplicity.

  For example, in the modification of pressure-sensitive adhesive, adhesion to soft PVC can be improved by graft polymerization of a monomer having a Tg of 273K or higher in the presence of an acrylic copolymer having a polar group. An adhesive is disclosed (for example, see Patent Document 1). Moreover, the graft adhesive which polymerized the acrylic monomer mixture which has adhesiveness in presence of the polymer whose Tg is 273K or more is disclosed (for example, refer patent documents 2-5).

  Since these methods are graft polymerizations that start with a hydrogen abstraction reaction to the trunk polymer, there is a drawback that the formation of homopolymers always occurs, but it is simpler than the macromonomer method or the polymer reaction method. In addition, it has been used for a long time because it can be modified by taking advantage of the characteristics of the trunk polymer and the characteristics can be easily changed.

  However, the modified polymer produced using such a method has a problem in that the long-term storage stability at high temperatures is inferior. The reason for this is not clear, but it is also considered that the hydrogen abstraction reaction itself performed in the presence of polymerization is involved. In addition, when chain transfer to the main chain occurs, there is a possibility that a site having poor heat resistance may be created. Furthermore, in accordance with this idea, the addition of an anti-aging agent and the like was recognized as effective, but it was still insufficient.

Japanese Patent Publication No.58-1712 JP-A-8-165462 JP-A-8-176519 JP-A-10-140102 JP 2000-303048 A

  Then, this invention aims at providing the adhesive composition which exhibits the adhesive characteristic outstanding after the crosslinking process, and is excellent in heat resistance and re-peelability in order to cope with the above-mentioned problem.

  Another object of the present invention is to provide a method for producing a modified (meth) acrylic polymer (B) having excellent adhesive properties and heat resistance.

  Moreover, an object of this invention is to provide the adhesive layer formed with the said adhesive composition, and its manufacturing method. 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 synthesis method of the (meth) acrylic polymer and the composition of the pressure-sensitive adhesive composition, and as a result, found the following pressure-sensitive adhesive composition and pressure-sensitive adhesive layer. The invention has been completed.

That is, the pressure-sensitive adhesive composition of the present invention has, as a monomer unit, a general formula CH ₂ ═C (R ¹ ) COOC _n H _2n OH (where R ¹ is hydrogen or a methyl group, and n is an integer of 4 to 10). The glass transition temperature (Tg) of the homopolymer is that of the polymer (A) with respect to 100 parts by weight of the (meth) acrylic polymer (A) containing 0.2 to 10% by weight of the (meth) acrylic monomer represented by Base polymer of modified (meth) acrylic polymer (B) obtained by blending and polymerizing 10 to 200 parts by weight of monomer (a) higher than Tg and 0.02 to 5 parts by weight of peroxide An adhesive composition,
It contains 0.01 to 2 parts by weight of a crosslinking agent with respect to 100 parts by weight of the base polymer.

  Further, the method for producing a pressure-sensitive adhesive layer includes a step of forming a layer made of the pressure-sensitive adhesive composition on one or both sides of a support, and a step of crosslinking the layer made of the pressure-sensitive adhesive composition. And

Moreover, the manufacturing method of the modified (meth) acrylic polymer (B) of the present invention has a general formula CH ₂ ═C (R ¹ ) COOC _n H _2n OH (where R ¹ is hydrogen or a methyl group, n is an integer of 4 to 10) The glass transition temperature of the homopolymer with respect to 100 parts by weight of the (meth) acrylic polymer (A) containing 0.2 to 10% by weight of the (meth) acrylic monomer represented by (Tg) (A) It has the process of mix | blending and polymerizing 10-200 weight part of monomers (a) higher than Tg of a polymer, and a peroxide 0.02-5 weight part, It is characterized by the above-mentioned. .

  According to the present invention, as shown in the results of the examples, the modified (meth) acrylic polymer (B) having a specific monomer composition, and a pressure-sensitive adhesive composition containing a specific amount of a crosslinker are cross-linked, thereby removing again. The pressure-sensitive adhesive layer is superior in durability and workability, is free from floating or peeling off by heat treatment or high-humidity treatment, has excellent durability, and has an improved refractive index.

  The details of the reason why the pressure-sensitive adhesive composition exhibits such properties are not clear, but are presumed as follows. It is considered that a homopolymer composed of the monomer (a) is also produced by polymerizing the monomer (a) in the presence of the (meth) acrylic polymer (A). Graft polymerization to the acrylic polymer (A) is also considered to occur. As a result, the polymer or domain comprising the other monomer (a) composition having a high glass transition temperature (Tg) is the above (meth) acrylic polymer. (A) It is thought that it will be in the state which exists uniformly in. The modified (meth) acrylic polymer (B) is composed of another monomer composition having a high glass transition temperature (Tg) by crosslinking with a specific amount of a crosslinking agent such as an isocyanate crosslinking agent or a peroxide. Presumed to exhibit the above characteristics as a result of a good balance of polymer and domains localized in the side chain, moderate interaction between the copolymers, and main chain crosslinking with excellent relaxation properties by the crosslinking agent. Is done.

  In addition, according to the present invention, as shown in the results of the examples, re-peeling is performed by polymerization using a (meth) acrylic polymer (A) having a specific monomer composition and a specific monomer (a). It is easy to obtain a modified (meth) acrylic polymer (B) with excellent durability and improved refractive index, which has excellent properties and workability, and does not float or peel off due to heat treatment or high humidity treatment. .

  The above production method relates to graft polymerization in which the monomer (a) having another composition is polymerized in the presence of the (meth) acrylic polymer (A) having a specific hydroxyl group. The effect of improving heat resistance can be seen by using a polymer. Furthermore, it is preferable that the glass transition temperature (Tg) of the (meth) acrylic polymer is 250 K or less, and the glass transition temperature (Tg) of the homopolymer of the monomer to be graft polymerized is the above (meth) acrylic. It is preferable to make it higher than Tg of the polymer. By using the modified (meth) acrylic polymer (B) obtained by such a production method, by moderately crosslinking this, the increase in the adhesive strength after sticking is very small, and after sticking for a long time However, it is an adhesive layer that can be easily removed without leaving any adhesive residue.

The modified (meth) acrylic polymer (B) in the present invention has the general formula CH ₂ ═C (R ¹ ) COOC _n H _2n OH (where R ¹ is hydrogen or a methyl group, and n is an integer of 4 to 10). The glass transition temperature (Tg) of the homopolymer is higher than the Tg of the polymer with respect to 100 parts by weight of the (meth) acrylic polymer (A) containing 0.2 to 10% by weight of the (meth) acrylic monomer represented by It is obtained by blending and polymerizing 10 to 200 parts by weight of monomer (a) and 0.02 to 5 parts by weight of peroxide.

  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 is characterized by containing 0.01 to 2 parts by weight of a crosslinking agent with respect to 100 parts by weight of the base polymer.

  In the pressure-sensitive adhesive composition of the present invention, the glass transition temperature (Tg) of the homopolymer is more preferably 300K or higher.

  Moreover, it is preferable that the glass transition temperature of the said (meth) acrylic-type polymer (A) is 250 K or less.

The monomer (a) is represented by the general formula CH ₂ = C (R ¹ ) COOC _n H _2n OH (where R ¹ is hydrogen or a methyl group, and n is an integer of 4 to 10). It is preferable that 1 to 15% by weight of (meth) acrylic monomer is contained. By using the monomer (a) having the above composition, the transparency of the obtained graft polymer is improved, but this is presumed to be due to an improvement in the compatibility of the backbone polymer and the side chain polymer.

  Further, the monomer (a) is preferably a monomer having an aromatic ring. By using such a monomer, the refractive index can be increased and the interface reflection can be reduced more reliably.

  Moreover, in the adhesive composition of this invention, it is preferable to contain 10-100 weight part of tackifiers with respect to 100 weight part of said base polymers. In particular, by using a tackifier having a large refractive index, the refractive index can be increased more reliably and the interface reflection can be reduced.

  Moreover, it is preferable that the said adhesive composition is used for an optical member use.

  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, it is obtained by crosslinking a pressure-sensitive adhesive composition that exhibits the above-described effects, so that it is excellent in removability and workability, and is not floated or peeled off by heat treatment or high-humidity treatment. It becomes the adhesive layer excellent in durability which does not arise. Moreover, in order to produce the above effects, it is particularly suitable for use as an optical member.

  Furthermore, in the said adhesive layer, it is preferable that the gel fraction of the said adhesive layer is 40 to 90 weight%.

  Moreover, in the said adhesive layer, it is preferable that the haze value of the said adhesive layer is 30% or less.

  On the other hand, the pressure-sensitive adhesive layer of the present invention includes, for example, a step of forming a layer made of the above-mentioned pressure-sensitive adhesive composition on one or both sides of a support and a cross-linking treatment of the layer made of the pressure-sensitive adhesive composition. It can obtain by using the manufacturing method including a process to do. By using such a production method, it is possible to easily obtain a pressure-sensitive adhesive layer having excellent re-peelability and workability, superior in durability and free from peeling or peeling due to heat treatment or high-humidity treatment, and having an improved refractive index. be able to.

  In the present invention, the peroxide crosslinking treatment refers to a treatment in which the peroxide is decomposed by heat or light irradiation to generate radicals to crosslink the base polymer. Moreover, it is preferable that the said peroxide crosslinking process is a process which decomposes | disassembles the said peroxide 50weight% or more.

  Furthermore, in the said manufacturing method, it is preferable that the gel fraction of the said adhesive layer is 40 to 90 weight%.

  On the other hand, the optical member with an adhesive of the present invention is characterized in that the above-mentioned adhesive layer is formed on one side or both sides of the optical member. According to the pressure-sensitive adhesive optical member of the present invention, since it has a pressure-sensitive adhesive layer that exhibits the above-described effects, it is excellent in removability and workability, and does not float or peel off due to heat treatment or high-humidity treatment. It becomes the optical member with an adhesive which was excellent in durability and improved the refractive index. In a preferred embodiment, the optical member is a microlens.

  Further, the image display device of the present invention is a liquid crystal display device, an organic EL display device, a PDP, various backlights, an illumination light source, etc. using the above-mentioned optical member with an adhesive, and has excellent removability and workability. At the same time, it has a function of exhibiting high durability that does not cause floating or peeling due to heat treatment or high humidity treatment.

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

The pressure-sensitive adhesive composition of the present invention has a general formula CH ₂ ═C (R ¹ ) COOC _n H _2n OH (where R ¹ is hydrogen or a methyl group, and n is an integer of 4 to 10) as a monomer unit. With respect to 100 parts by weight of the (meth) acrylic polymer (A) containing 0.2 to 10% by weight of the (meth) acrylic monomer represented, the glass transition temperature (Tg) of the homopolymer is from the Tg of the (A) polymer. A modified (meth) acrylic polymer (B) obtained by blending and polymerizing 10 to 200 parts by weight of a high monomer (a) and 0.02 to 5 parts by weight of a peroxide is used as a base polymer. An adhesive composition comprising:
It contains 0.01 to 2 parts by weight of a crosslinking agent with respect to 100 parts by weight of the base polymer.

  Further, the method for producing a pressure-sensitive adhesive layer includes a step of forming a layer made of the pressure-sensitive adhesive composition on one or both sides of a support, and a step of crosslinking the layer made of the pressure-sensitive adhesive composition. And

Moreover, the manufacturing method of the modified (meth) acrylic polymer (B) of the present invention has a general formula CH ₂ ═C (R ¹ ) COOC _n H _2n OH (where R ¹ is hydrogen or a methyl group, n is an integer of 4 to 10) The glass transition temperature of the homopolymer with respect to 100 parts by weight of the (meth) acrylic polymer (A) containing 0.2 to 10% by weight of the (meth) acrylic monomer represented by (Tg) (A) It has the process of mix | blending and polymerizing 10-200 weight part of monomers (a) higher than Tg of a polymer, and a peroxide 0.02-5 weight part, It is characterized by the above-mentioned. .

  The pressure-sensitive adhesive composition of the present invention is characterized by containing the modified (meth) acrylic polymer (B) as a base polymer.

The (meth) acrylic polymer (A) has, as a monomer unit, a general formula CH ₂ ═C (R ¹ ) COOC _n H _2n OH (where R ¹ is hydrogen or a methyl group, and n is an integer of 4 to 10). (Meth) acrylic monomer represented by 0.2 to 10% by weight.

In the above general formula, R ¹ is hydrogen or a methyl group. Moreover, in the said general formula, n is an integer of 4-10, However, It is preferable that it is 4-8. It is more preferable that it is 4-6.

Specific examples of the (meth) acrylic monomer represented by the general formula CH ₂ ═C (R ¹ ) COOC _n H _2n OH include, for example, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl ( And (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, and the like. Of these, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and the like are preferable.

The (meth) acrylic polymer (A) has, as a monomer unit, a general formula CH ₂ ═C (R ¹ ) COOC _n H _2n OH (where R ¹ is hydrogen or a methyl group, and n is an integer of 4 to 10). (Meth) acrylic monomer represented by 0.2 to 10% by weight, preferably 0.2 to 7 parts by weight, and more preferably 0.5 to 5 parts by weight. If the amount used is too large, the polymerization stability may be impaired. On the other hand, if the amount used is too small, the resulting graft polymer may have poor heat resistance.

  Moreover, in the (meth) acrylic-type polymer (A) of this invention, a carboxyl group-containing monomer can be used as a monomer unit.

  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. These monomers may be used alone or in combination of two or more.

  The content of the carboxyl group-containing monomer is preferably 0.1 to 20% by weight, more preferably 0.2 to 10% by weight, based on the whole monomer of the (meth) acrylic polymer. More preferably, it is 5 to 7% by weight. When the content exceeds 20% by weight, the viscosity may increase and the productivity may be hindered. On the other hand, when the content is less than 0.1% by weight, the internal cohesive force is insufficient and the cohesive failure occurs. May end up.

  Furthermore, in the (meth) acrylic polymer (A) of the present invention, as a monomer other than the above-mentioned monomers, a polymerizable monomer for adjusting the glass transition point and peelability of the (meth) acrylic polymer (A), etc. Can be used as long as the effects of the present invention are not impaired.

  Examples of other polymerizable monomers used in the (meth) acrylic polymer of the present invention include acrylic acid alkyl esters having 2 to 14 carbon atoms, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, and cyano. Adhesion improvement and cross-linking such as cohesive strength and heat resistance improving components such as group-containing monomers, vinyl ester monomers, aromatic vinyl monomers, amide group-containing monomers, amino group-containing monomers, imide group-containing monomers, and epoxy group-containing monomers A component having a functional group serving as a linking base point can be appropriately used. Among them, those having a ring structure such as cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, styrene and the like have a high refractive index of the homopolymer, and further improvement of the refractive index can be expected by copolymerization. These monomer compounds may be used alone or in admixture of two or more.

As the acrylic acid alkyl ester having an alkyl group having 2 to 14 carbon atoms, as a monomer unit, a general formula CH ₂ ═C (R ¹ ) COOR ² (where R ¹ is hydrogen or a methyl group, R ² is carbon number) 2 to 14 alkyl groups).

In the above general formula, R ¹ is hydrogen or a methyl group. In the above general formula, R ² is an alkyl group having 2 to 14 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 4 to 9 carbon atoms, still more preferably 4 to 8 carbon atoms. The alkyl group for R ² may 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 ¹ ) COOR ² include, for example, ethyl (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 (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate , N-dode (Meth) acrylate, isomyristyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, phenoxyethyl (meth) acrylate, etc. can give.

  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 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, and itaconimide.

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

  Examples of the (meth) acrylic monomer having an alkyl group having 1 or 15 carbon atoms include methyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, and the like.

  The (meth) acrylic polymer (A) preferably has a weight average molecular weight of 600,000 or more, more preferably 700,000 to 3,000,000, and even more preferably 800,000 to 2,500,000. . If the weight average molecular weight is less than 600,000, 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.

Moreover, in this invention, it is preferable that the glass transition temperature (Tg) of the said (meth) acrylic-type polymer (A) is 250K or less, and it is more preferable that it is 240K or less. By using such a (meth) acrylic polymer (A), a pressure-sensitive adhesive composition having good heat resistance and excellent internal cohesive strength is obtained. In addition, the glass transition temperature (Tg) of (meth) acrylic-type polymer (A) can be adjusted in the said range by changing the monomer component and composition ratio to be used suitably. Moreover, about the glass transition temperature (Tg) of a copolymer, it calculates and calculates | requires from the following Fox formula.
1 / Tg = W1 / Tg1 + W2 / Tg2 + W3 / Tg3 +
The above Tg1, Tg2, Tg3, etc. represent the glass transition temperatures of the respective copolymer components 1, 2, 3, etc. in terms of absolute temperature, and W1, W2, W3, etc. represent the respective copolymer components. Weight fraction. In addition, the glass transition temperature (Tg) of the single polymer was obtained from Polymer Handbook (4 edition, John Wiley & Sons. Inc.).

  For the production of such a (meth) acrylic polymer (A), known production methods such as solution polymerization, bulk polymerization, emulsion polymerization, and various radical polymerizations can be appropriately selected. Further, the (meth) acrylic polymer (A) to be 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 addition, when a peroxide is used as a polymerization initiator, it is possible to use the remaining peroxide for the crosslinking reaction without being used in the polymerization reaction. If necessary, it can be added again and used in a predetermined amount of peroxide.

  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 (A) 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 (manufactured by Asahi Denka Kogyo Co., Ltd.), and the like. Reactive emulsifiers are preferable because they are incorporated into the polymer chain after polymerization and thus have improved water resistance. The amount of the emulsifier used is more preferably 0.3 to 5 parts by weight and 0.5 to 1 part by weight with respect to 100 parts by weight of the monomer in view of polymerization stability and mechanical stability.

  The modified (meth) acrylic polymer (B) of the present invention has a homopolymer glass transition temperature (Tg) of (meth) acrylic polymer (100) relative to 100 parts by weight of the (meth) acrylic polymer (A). It is obtained by mixing and polymerizing 10 to 200 parts by weight of the monomer (a) higher than Tg of A) and 0.02 to 5 parts by weight of peroxide.

  As the monomer (a), a (meth) acrylic monomer that has a higher glass transition temperature (Tg) of the homopolymer than the (meth) acrylic polymer (A) domain serving as the main chain is used. These may be used singly or in combination of two or more. When it is lower than Tg of the (meth) acrylic polymer (A) domain, the cohesive force of the pressure-sensitive adhesive is lowered, and the durability may be inferior.

  The Tg of the homopolymer is preferably 300K or more, more preferably 300 to 430K. If the Tg is less than 300K, the cohesive force of the pressure-sensitive adhesive is lowered, and the durability may be inferior.

  Furthermore, the monomer (a) is preferably a monomer having an aromatic group (aromatic ring). By using such a monomer, the refractive index can be increased and the interface reflection can be reduced more reliably.

  Examples of the monomer (a) include t-butyl acrylate (Tg314K), lauryl acrylate (Tg288K), butyl methacrylate (Tg293K), stearyl acrylate (303K), isobornyl acrylate (370K), isobornyl methacrylate ( 453K), cyclohexyl acrylate (288K), dicyclopentanyl acrylate (393K), and the like.

  In particular, the monomer (a) is preferably a monomer having the aromatic group. For example, (meth) acrylic compounds such as phenoxyethyl acrylate (Tg251K), benzylacrylate (Tg279K), and benzylmethacrylate (Tg327K). Monomers, and styrene monomers such as styrene (Tg373K), α-methylstyrene (Tg371K), 2,4-dimethylstyrene (Tg385K), and 4-benzoylstyrene (Tg371K).

The monomer (a) is represented by the general formula CH ₂ = C (R ¹ ) COOC _n H _2n OH (where R ¹ is hydrogen or a methyl group, and n is an integer of 4 to 10). It is preferable that 1 to 15% by weight of (meth) acrylic monomer is contained. By using the monomer (a) having the above composition, the transparency of the obtained graft polymer is improved, but this is presumed to be due to an improvement in the compatibility of the backbone polymer and the side chain polymer.

  In addition, as a graft polymerization method of the monomer (a), in the case of solution polymerization, a necessary monomer and a viscosity-adjusted solvent are added to the solution of the (meth) acrylic polymer (A), After nitrogen substitution, a method such as adding a peroxide type polymerization initiator such as dibenzoyl peroxide and heating at 50 ° C. to 80 ° C. for 4 to 15 hours to terminate the reaction can be used.

  In addition, if it is emulsion polymerization, water for adjusting the solid content is added to the aqueous dispersion of the (meth) acrylic polymer (A), the necessary monomer is further added, and nitrogen substitution is performed while stirring. (Meth) acrylic polymer particles are allowed to absorb the monomer, and then a polymerization initiator such as water-soluble ammonium persulfate or potassium persulfate is added and heated at 50 to 80 ° C. for 4 to 15 hours. A method for terminating the reaction can be mentioned.

  In the present invention, the monomer (a) is polymerized by blending 10 to 200 parts by weight with respect to 100 parts by weight of the (meth) acrylic polymer (A). It is preferably blended and polymerized, more preferably 20 to 80 parts by weight, and even more preferably 20 to 50 parts by weight, and particularly preferably polymerized. In particular, when a monomer having an aromatic group is used, if the amount of the monomer having an aromatic group is decreased, the compatibility with the tackifier is reduced, and blending with the tackifier is not preferable. On the other hand, if the amount of the monomer having an aromatic group is too large, the adhesive property is lowered, which is not preferable.

  In the graft polymerization, if the amount of peroxide used as the polymerization initiator is small, it takes too much time for the graft polymerization reaction, and if it is too large, a large amount of monomer homopolymer is generated.

By doing in this way, the graft polymer with favorable heat resistance as described in an Example can be polymerized. The reason why such a feature can be expressed is not clear, but it is contained in 0.2 to 10 parts by weight in the trunk polymer that is an essential component of the present invention. One general formula CH ₂ ═C (R ¹ ) COOC _n Positions and grafts where hydrogen abstraction occurs due to the significant influence of (meth) acrylate having a hydroxyl group represented by H _2n OH (where R ¹ is hydrogen or a methyl group, and n is an integer of 4 to 10) It is presumed that the compatibility with the produced homopolymer is involved in a complex manner.

  On the other hand, in the present invention, by using the (meth) acrylic polymer (A) having a glass transition temperature (Tg) of 250 K or less as the trunk polymer, a pressure-sensitive adhesive composition having good heat resistance is obtained. Furthermore, a pressure-sensitive adhesive composition excellent in heat resistance and the like can be obtained using a modified (meth) acrylic polymer (B) graft-polymerized using a monomer having a Tg higher than that of the polymer (A) as the branch polymer. it can.

  The pressure-sensitive adhesive composition of the present invention is based on the modified (meth) acrylic polymer (B) as described above.

  Moreover, in the adhesive composition of this invention, it is preferable to contain a crosslinking agent.

  Examples of the crosslinking agent include a polyfunctional compound that can react with a functional group (such as a hydroxyl group) in a (meth) acrylic polymer to form a crosslinked structure, and a crosslinking agent that crosslinks other than the functional group in the (meth) acrylic polymer. Etc. can be used.

  Examples of the crosslinking agent that reacts with a hydroxyl group include an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine compound, a melamine compound, a metal salt, and a metal chelate compound. Of these, the combined use of an isocyanate crosslinking agent and a peroxide is particularly preferably used.

  Moreover, it is also preferable to use an organic peroxide as a crosslinking agent as the crosslinking agent.

  The above peroxides may be used alone or in combination of two or more. Of these, the combined use of an isocyanate crosslinking agent and a peroxide is particularly preferably used.

  The isocyanate-based crosslinking agent in the present invention refers to an isocyanate compound having two or more isocyanate groups (including isocyanate-regenerating functional groups in which isocyanate groups are temporarily protected by blocking agents, quantification, etc.) in one molecule. .

  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. Of these, aliphatic isocyanates and alicyclic isocyanates are particularly preferably used since the crosslinked product becomes transparent.

  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.

  In addition, when an isocyanate-based crosslinking agent is used in an aqueous dispersion of a modified (meth) acrylic polymer (B) produced by emulsion polymerization, the isocyanate-based crosslinking blocked because the isocyanate group easily reacts with water. An agent may be used.

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

  Examples of the epoxy-based crosslinking agent include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, terephthalic acid diglycidyl ester acrylate, spiroglycol diglycidyl ether, and the like.

  The organic peroxide of the present invention can be used as appropriate as long as it generates radical active species by heating or light irradiation to advance the crosslinking of the base polymer of the pressure-sensitive adhesive composition. In view of the above, it is preferable to use an organic peroxide having a one-minute half-life temperature of 80 ° C to 160 ° C, and more preferable to use an organic peroxide having a temperature of 90 ° C to 140 ° C. If the half-life temperature for 1 minute is too low, the reaction proceeds at the time of storage before coating and drying, and the viscosity may become high and the coating may become impossible. On the other hand, if the half-life temperature is too high, Since the temperature becomes high, side reactions occur, and a large amount of unreacted organic peroxide remains, which may cause crosslinking over time.

  Examples of the organic peroxide used in the present invention include di (2-ethylhexyl) peroxydicarbonate (1 minute half-life temperature: 90.6 ° C.), di (4-t-butylcyclohexyl) peroxydicarbonate. (1 minute half-life temperature: 92.1 ° C.), di-sec-butyl peroxydicarbonate (1 minute half-life temperature: 92.4 ° C.), t-butyl peroxyneodecanoate (1 minute half-life temperature : 103.5 ° C), t-hexyl peroxypivalate (half-life temperature for 1 minute: 109.1 ° C), t-butyl peroxypivalate (half-life temperature for 1 minute: 110.3 ° C), dilauroyl par Oxide (1 minute half-life temperature: 116.4 ° C.), di-n-octanoyl peroxide (1 minute half-life temperature: 117.4 ° C.), 1,1,3,3-tetramethylbutyrate Peroxy-2-ethylhexanoate (1 minute half-life temperature: 124.3 ° C), di (4-methylbenzoyl) peroxide (1 minute half-life temperature: 128.2 ° C), dibenzoyl peroxide (half-minute for 1 minute) Period temperature: 130.0 ° C.), t-butyl peroxyisobutyrate (1 minute half-life temperature: 136.1 ° C.), 1,1-di (t-hexylperoxy) cyclohexane (1 minute half-life temperature: 149.2 ° C.). Especially, since the crosslinking reaction efficiency is excellent, di (4-t-butylcyclohexyl) peroxydicarbonate (1 minute half-life temperature: 92.1 ° C.), dilauroyl peroxide (1 minute half-life temperature: 116. 4 ° C), dibenzoyl peroxide (1 minute half-life temperature: 130.0 ° C) and the like are preferably used.

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

  The crosslinking agent such as the organic peroxide may be used alone, or may be used in combination of two or more, but the total content is based on 100 parts by weight of the base polymer. It is preferable to contain 0.02 to 2 parts by weight of a crosslinking agent, more preferably 0.05 to 1.0 parts by weight, and still more preferably 0.08 to 0.6 parts by weight. If the amount is less than 0.02 parts by weight, the cross-linking may be insufficient and the durability may be poor. On the other hand, if the amount exceeds 2 parts by weight, the cross-linking may be excessive and the adhesiveness may be poor.

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

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

  In the present invention, the addition amount of a crosslinking agent (such as an organic peroxide, an isocyanate crosslinking agent, or an epoxy crosslinking agent) is adjusted so that the gel fraction of the crosslinked pressure-sensitive adhesive layer is 40 to 90% by weight. It is preferable to adjust, and it is more preferable to adjust the addition amount of the crosslinking agent to be 45 to 85% by weight, and it is further preferable to adjust the addition amount of the crosslinking agent to be 50 to 80% by weight. preferable. When the gel fraction is smaller than 40% by weight, the cohesive force is lowered, so that the durability may be inferior. When it exceeds 90% by weight, the stress relaxation property may be inferior. Furthermore, when a crosslinking agent is used in combination (isocyanate-based crosslinking agent and organic oxide), the crosslinking ratio of both is preferably 10 to 75% by weight when the gel content of the peroxide alone is measured. .

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.

  In order to adjust to a predetermined gel fraction, it is necessary to fully consider the influence of the crosslinking treatment temperature and the crosslinking treatment time as well as adjusting the addition amount of a crosslinking agent such as a peroxide or an isocyanate crosslinking agent.

  The adjustment of the crosslinking treatment temperature and the crosslinking treatment time is, for example, preferably set so that the decomposition amount of the peroxide contained in the pressure-sensitive adhesive composition is 50% by weight or more, and is set to be 60% by weight or more. It is more preferable to set it to 70% by weight or more. When the peroxide decomposition amount is less than 50% by weight, the amount of peroxide remaining in the pressure-sensitive adhesive composition increases, and a crosslinking reaction over time may occur even after the crosslinking treatment.

  More specifically, for example, at a crosslinking treatment temperature of 1 minute half-life temperature, the decomposition amount of peroxide is 50% by weight in 1 minute, and the decomposition amount of peroxide is 75% by weight in 2 minutes. A crosslinking treatment time of 1 minute or more is required. Further, for example, if the peroxide half-life (half-life time) at the crosslinking treatment temperature is 30 seconds, a crosslinking treatment time of 30 seconds or more is required, and for example, the peroxide half-life at the crosslinking treatment temperature. If the (half time) is 5 minutes, a crosslinking treatment time of 5 minutes or more is required.

  Thus, the crosslinking treatment temperature and crosslinking treatment time can be calculated by theoretical calculation from the half-life (half-life time) assuming that the peroxide is linearly proportional to the peroxide used. It can be adjusted as appropriate. On the other hand, the higher the temperature, the higher the possibility of side reactions, so the crosslinking treatment temperature is preferably 170 ° C. or lower.

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

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

  The pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition thus obtained has a very small increase in adhesive strength after being applied to an adherend, and it is easy without adhesive residue even after being applied for a long time. It can be removed again.

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

  Specifically, for example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltri Epoxy group-containing silane coupling agents such as methoxysilane, 3-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3 Amino group-containing silane coupling agents such as -triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine, (meth) such as 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane Acrylic group-containing silane coupling And Inshianeto group-containing silane coupling agents such as 3-isocyanate propyl triethoxysilane and the like. Use of such a silane coupling agent is preferable for improving durability.

  The silane coupling agent may be used alone or in combination of two or more, but the total content is 100 parts by weight of the (meth) acrylic polymer (A). On the other hand, it is preferable to contain 0.01 to 1 part by weight of the silane coupling agent, more preferably 0.02 to 0.6 part by weight, and further 0.05 to 0.3 part by weight. preferable. By using the silane coupling agent in the above range, it can be more reliably improved cohesive strength and durability, but if less than 0.01 parts by weight, the durability may be inferior, On the other hand, if the amount exceeds 1 part by weight, the adhesive force to an optical member such as a liquid crystal cell may increase excessively.

  In addition, a tackifier can be used in the pressure-sensitive adhesive composition of the present invention for the purpose of further improving adhesive strength, durability, and refractive index.

  As the tackifier, known ones can be appropriately used without particular limitation, but it is preferable to use a tackifier having an aromatic ring or a hydrogenated product thereof and having a refractive index of 1.51 to 1.75. The refractive index is more preferably 1.53 to 1.65, and further preferably 1.54 to 1.63. In addition, since a colored tackifier colors an adhesive composition, a transparent tackifier is preferably used. As a standard of the transparent tackifier, those having a Gardner hue of 1 or less in a 50 wt% toluene solution of the tackifier are preferably used.

  Moreover, when using a tackifier, it is preferable that the refractive index of the modified (meth) acrylic polymer (B) is 1.48 to 1.54, since the compatibility with the tackifier is improved. More preferably, it is 1.53. The refractive index of the acrylic copolymer can be controlled to be in the above range by adjusting the copolymerization ratio of the monomer having an aromatic group. In addition, the modified (meth) acrylic polymer (B) having the above refractive index has good compatibility with the tackifier, so that the addition of the tackifier is effective in improving the refractive index, and the adhesive properties are also good. become.

  Specific examples of the tackifier include, for example, a styrene oligomer, a phenoxyethyl acrylate oligomer, a copolymer of styrene and α-methylstyrene, a copolymer of vinyltoluene and α-methylstyrene, a hydrogenated product of C9 petroleum resin, and a terpene. Examples thereof include phenols and hydrogenated products thereof, rosin phenols and hydrogenated products thereof, aromatic petroleum resins and hydrogenated products thereof. Among these, a styrene oligomer and a copolymer of styrene and α-methylstyrene are preferable.

  Moreover, it is preferable to reduce the content of the tackifier having a softening point of 40 ° C. or lower. Furthermore, it is preferable that it is 60 degreeC or more and 70-160 degreeC. When a tackifier having a softening point of less than 40 ° C. is used, the amount used is less than 20 parts by weight, and in combination with a tackifier having a softening point of 50 ° C. or more, 20 parts by weight (total of 40 parts by weight) or more. It is preferable to use it from the viewpoint of heat resistance.

  Moreover, it is preferable that the weight average molecular weights of the said tackifier are 1000-6000, It is more preferable that it is 1000-4000, It is further more preferable that it is 1000-3000. Moreover, it is preferable from the surface of the compatibility of a polymer that the softening point of a tackifier does not exceed 90 degreeC.

  Moreover, it is preferable to contain 10-100 weight part of the said tackifier with respect to 100 weight part of said base polymers, It is more preferable to contain 20-80 weight part, It is more preferable to contain 30-50 weight part. The pressure-sensitive adhesive composition is adjusted to a predetermined refractive index by such a blending amount. That is, the refractive index of the pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive layer is preferably adjusted to be 1.51 to 1.75, preferably 1.52 to 1.66. If the amount of the tackifier is too small, the refractive index is not sufficiently increased. On the other hand, if the amount is too large, the pressure-sensitive adhesive layer becomes hard and the internal cohesive force is lowered.

  Furthermore, the pressure-sensitive adhesive composition of the present invention may contain other known additives, such as powders such as colorants and pigments, dyes, surfactants, plasticizers, surface lubricants, and leveling. As appropriate depending on the use of the agent, softener, antioxidant, anti-aging agent, light stabilizer, ultraviolet absorber, polymerization inhibitor, inorganic or organic filler, metal powder, particles, foil, etc. Can be added. 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 obtained 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 performing a crosslinking treatment with a crosslinking agent such as a product.

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

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

  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 perform 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.

  The pressure-sensitive adhesive layer in the present invention is obtained by cross-linking the pressure-sensitive adhesive composition with the peroxide, so that these properties do not require aging after the steps of coating, drying, cross-linking and transfer, and are stamped. It becomes a pressure-sensitive adhesive layer with excellent productivity that can be quickly processed.

  Moreover, in the said adhesive layer, it is preferable that the thickness of the said adhesive layer is 2-500 micrometers, and it is more preferable that it is 5-100 micrometers.

  Furthermore, the haze value of the pressure-sensitive adhesive layer is preferably 30% or less, more preferably 25% or less, and further preferably 20% or less. If the haze value exceeds 30%, the transmittance is greatly reduced when laminated on an optical member, which is not preferable. In the modified (meth) acrylic polymer (B) obtained by polymerizing other monomers in the presence of the (meth) acrylic polymer (A) as in the present invention, the homopolymers of the monomers are compatible with each other. Even if it is difficult to form, even if it is phase-separated, the domain is small, so that the haze value does not increase and the transmittance can hardly be lowered. For this reason, what uses the range of the said haze value can be easily obtained by using the adhesive composition and adhesive layer of this invention.

  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 in the single side | surface or both surfaces of an optical member. Since the optical member with pressure-sensitive adhesive of the present invention includes a pressure-sensitive adhesive layer that exhibits the above-described effects, it has excellent removability and workability, and does not float or peel off due to heat treatment or high-humidity treatment. It has excellent properties and has an improved refractive index.

  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, the optical member includes an optical film such as a polarizing plate. 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 external light from reflecting on the surface of the polarizing plate and obstructing the visibility of the light transmitted through the polarizing plate. For example, roughening 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 method or a compounding 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.

  Examples of the optical member of the present invention include a reflective plate, a transflective plate, a retardation plate (including wavelength plates such as 1/2 and 1/4), a viewing angle compensation film, a brightness enhancement film, and a liquid crystal such as a microlens. Examples thereof include an optical layer that may be used for forming a display device or the like. 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 in the manufacturing process of the liquid crystal display device so as to be a combination of a (reflective) polarizing plate and a retardation plate, as described above. In addition, an optical member such as an elliptically polarizing plate is advantageous in that it is excellent in quality stability, laminating workability and the like, and can improve the manufacturing efficiency of a liquid crystal display device and 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.

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

  A polarizing plate obtained by bonding a polarizing plate and a brightness enhancement film is usually provided on the back side of a liquid crystal cell. The brightness enhancement film reflects a linearly polarized light with a predetermined polarization axis or a circularly polarized light in a predetermined direction when natural light is incident due to a backlight such as a liquid crystal display device or reflection from the back side, and transmits other light. In addition, a polarizing plate in which a brightness enhancement film is laminated with a polarizing plate allows light from a light source such as a backlight to enter to obtain transmitted light in a predetermined polarization state, and reflects light without transmitting the light other than the predetermined polarization state. The The light reflected on the surface of the brightness enhancement film is further inverted through a reflective layer 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 the circularly polarized light is linearly polarized via a retardation plate in order to suppress absorption loss. It is preferable to make it enter into a 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.

  Moreover, the polarizing plate may consist of what laminated | stacked the polarizing plate and the optical layer of 2 layers or 3 layers or more like the above-mentioned 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.

  Moreover, the image display device of the present invention is a liquid crystal display device, an organic EL display device, a PDP, etc. using the optical member with an adhesive, and has excellent removability and workability, as well as heat treatment and high humidity treatment. It has a function capable of exhibiting high durability without causing lifting 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
Column: manufactured by Tosoh Corporation, G7000H _XL + GMH _XL + GMH _XL
Column size: 7.8mmφ x 30cm each (total 90cm)
-Column temperature: 40 ° C
・ Flow rate: 0.8ml / min
・ Injection volume: 100 μl
・ Eluent: Tetrahydrofuran ・ Detector: Differential refractometer (RI)
The molecular weight was calculated in terms of polystyrene.

<Measurement of peroxide decomposition amount>
The amount of peroxide decomposition after the thermal decomposition treatment was measured by HPLC (high performance liquid chromatography).

Specifically, about 0.2 g each of the pressure-sensitive adhesive composition before and after the decomposition treatment was taken out, immersed in 10 ml of ethyl acetate, and extracted by shaking at 25 ° C. and 120 rpm for 3 hours with a shaker. Let stand for days. Next, 10 ml of acetonitrile was added, shaken at 120 rpm at 25 ° C. for 30 minutes, and about 10 μl of the extract obtained by filtration through a membrane filter (0.45 μm) was injected into the HPLC for analysis. The decrease in the peroxide amount was defined as the peroxide decomposition amount.
・ Device: HPL CCPM / UV8000 manufactured by Tosoh Corporation
Column: NUCLEOSIL 7C18 (4.6 mmφ × 250 mm) manufactured by MACHEREY-NAGEL
・ Column flow rate: 1 ml / min
Column pressure: 41 kg / cm ²
-Column temperature: 40 ° C
・ Injection volume: 10 μl
Eluent: water / acetonitrile = 30/70
Injection sample concentration: 0.01% by weight
Detector: UV detector (230 nm).

<Measurement of gel fraction>
W 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>
The pressure-sensitive adhesive sheets (width 20 mm) obtained in Examples and Comparative Examples were attached to acrylic-free glass (Corning Corp., # 1737, thickness: 0.7 mm) by reciprocating the roll 1 with a 2 kg roller. Then, after processing for 30 minutes in an autoclave at 50 ° C. and 0.5 Mpa, the film was allowed to stand in an atmosphere of 23 ° C. × 50% RH for 3 hours, and then peel adhesive strength was measured at a peel angle of 90 ° and a peel speed of 300 mm / min.

<Evaluation of holding power>
The pressure-sensitive adhesive sheet having a width of 10 mm obtained in Examples and Comparative Examples is attached to a baking plate with an adhesive area of 10 × 20 mm, and a load of 500 g is applied to one side of the pressure-sensitive adhesive sheet and stored at a predetermined temperature (80 ° C.). The time until the sample dropped from the bake plate was measured and used as a measure of heat resistance.

<Measurement of refractive index>
Under an atmosphere of 25 ° C., sodium D line was irradiated, and the refractive index was measured using an appe refractometer (manufactured by ATAGO, DR-M4).

<Measurement of haze value>
By using a sample having a pressure-sensitive adhesive layer (20 μm) lined with 25 μm polyethylene terephthalate and using an HR-100 type (manufactured by Murakami Color Research Laboratory Co., Ltd.) under an atmosphere of 25 ° C. The haze value (%) was measured.

[Example 1]
(Preparation of acrylic polymer)
In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, and condenser, 99 parts by weight of n-butyl acrylate, 0.5 parts by weight of 4-hydroxybutyl acrylate, 0.5 parts by weight of acrylic acid, polymerization After charging 0.1 parts by weight of 2,2′-azobisisobutyronitrile and 200 parts by weight of ethyl acetate as an initiator, nitrogen gas was introduced while gently stirring and the atmosphere in the flask was sufficiently replaced with nitrogen. A polymerization reaction was carried out for 15 hours while maintaining the temperature at around 55 ° C. to prepare an acrylic polymer (a1) solution. The acrylic polymer (a1) had a weight average molecular weight of 1,800,000 and Tg of 220K.

(Preparation of modified acrylic polymer)
A four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a cooler, 400 parts by weight of the acrylic polymer (a1) solution diluted with ethyl acetate and diluted to 25% by weight, styrene (Tg: 373K) ) 50 parts by weight and 0.2 parts by weight of dibenzoyl peroxide as a polymerization initiator were introduced, nitrogen gas was introduced while gently stirring, and the atmosphere was sufficiently replaced with nitrogen. Then, the liquid temperature in the flask was kept at around 65 ° C. For 6 hours at 70 ° C. for 6 hours to prepare a modified acrylic polymer (b1) solution.

(Preparation of adhesive layer)
An acrylic pressure-sensitive adhesive solution (1) containing 0.2 parts by weight of dibenzoyl peroxide (1 minute half-life: 130 ° C.) as a crosslinking agent with respect to 100 parts by weight of the solid content of the modified acrylic polymer (b1) solution ) Was adjusted.

  Next, the acrylic pressure-sensitive adhesive solution (1) was applied to one side of a polyethylene terephthalate (PET) film (manufactured by Toray Industries, Inc., S-10, thickness: 38 μm), dried at 150 ° C. for 3 minutes, and after drying A pressure-sensitive adhesive layer having a thickness of 20 μm was formed. In addition, the decomposition rate of the peroxide at the time of drying at this time was 94 weight%. Moreover, the gel fraction (at room temperature for 5 days) and holding power (after storage at 80 ° C., room temperature × 5 days and 90 ° C. × 500 hours) of the pressure-sensitive adhesive layer were performed.

(Preparation of optical film with adhesive)
Further, the acrylic pressure-sensitive adhesive solution (1) 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. A pressure-sensitive adhesive layer having a thickness of 20 μm after drying was obtained, and transferred to a polarizing film in which a triacetyl cellulose film was bonded to both sides of a polyvinyl alcohol film which had been iodine-dyed and stretched to produce an optical film with a pressure-sensitive adhesive. .

[Example 2]
(Production of microlenses)
A polystyrene solution was prepared by dissolving 20 parts by weight of polystyrene resin (manufactured by PS Japan Co., Ltd., trade name: HH105) with respect to 100 parts by weight of toluene. The polystyrene solution was applied to a polyester film having a thickness of 24 μm (manufactured by Teijin DuPont Co., Ltd., trade name: PET film G2, refractive index: 1.50) and cured to a polystyrene layer having a thickness of 5 μm (refractive index: 1.59) was formed, and microlenses (f-number: 0.86) having a radius of 5 μm were obtained by hot pressing at 160 ° C.

(Preparation of optical film with adhesive)
The pressure-sensitive adhesive layer produced in Example 1 was transferred to the polyester film side to produce an optical film with a pressure-sensitive adhesive.

Example 3
(Preparation of acrylic polymer)
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 98.5 parts by weight of n-butyl acrylate, 1 part by weight of 4-hydroxybutyl acrylate, 0.5 part by weight of acrylic acid, polymerization After charging 0.1 parts by weight of 2,2′-azobisisobutyronitrile and 200 parts by weight of ethyl acetate as an initiator, nitrogen gas was introduced while gently stirring and the atmosphere in the flask was sufficiently replaced with nitrogen. A polymerization reaction was carried out for 15 hours while maintaining the temperature at around 55 ° C. to prepare an acrylic polymer (a2) solution. The acrylic polymer (a2) had a weight average molecular weight of 1,840,000 and Tg of 220K.

(Preparation of modified acrylic polymer)
A 4-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a cooler, 400 parts by weight of the acrylic polymer (a2) solution diluted with ethyl acetate and diluted to 25% by weight, styrene (Tg: 373K) ) 50 parts by weight and 0.2 parts by weight of dibenzoyl peroxide as a polymerization initiator were introduced, nitrogen gas was introduced while gently stirring, and the atmosphere was sufficiently replaced with nitrogen. Then, the liquid temperature in the flask was kept at around 65 ° C. For 6 hours at 70 ° C. for 6 hours to prepare a modified acrylic polymer (b2) solution.

(Preparation of adhesive layer)
An acrylic pressure-sensitive adhesive solution (2) containing 0.2 parts by weight of dibenzoyl peroxide (1 minute half-life: 130 ° C.) as a crosslinking agent with respect to 100 parts by weight of the solid content of the modified acrylic polymer (b2) solution. ) Was adjusted.

  Next, the acrylic pressure-sensitive adhesive solution (2) was applied to one side of a polyethylene terephthalate (PET) film (manufactured by Toray Industries Inc., S-10, thickness: 38 μm), dried at 150 ° C. for 3 minutes, and after drying A pressure-sensitive adhesive layer having a thickness of 20 μm was formed. In addition, the decomposition rate of the peroxide at the time of drying at this time was 93 weight%. Moreover, the gel fraction (at room temperature for 5 days) and holding power (after storage at 80 ° C., room temperature × 5 days and 90 ° C. × 500 hours) of the pressure-sensitive adhesive layer were performed.

[Comparative Example 1]
(Preparation of modified acrylic polymer)
In Example 1, instead of 0.2 part by weight of dibenzoyl peroxide, the same operation as in Example 1 was performed except that 0.2 part by weight of 2,2′-azobisisobutyronitrile was used, A modified (meth) acrylic polymer (b3) solution was prepared.

(Preparation of adhesive layer)
An acrylic pressure-sensitive adhesive solution (3) in which 0.2 parts by weight of dibenzoyl peroxide (half-life of 1 minute: 130 ° C.) is blended as a crosslinking agent with respect to 100 parts by weight of the solid content of the modified acrylic polymer (b3) solution. ) Was adjusted.

  Next, the acrylic pressure-sensitive adhesive solution (3) was applied to one side of a polyethylene terephthalate (PET) film (manufactured by Toray Industries Inc., S-10, thickness: 38 μm), dried at 150 ° C. for 3 minutes, and after drying A pressure-sensitive adhesive layer having a thickness of 20 μm was formed. In addition, the decomposition rate of the peroxide at the time of drying at this time was 94 weight%. Moreover, the gel fraction (at room temperature for 5 days) and holding power (after storage at 80 ° C., room temperature × 5 days and 90 ° C. × 500 hours) of the pressure-sensitive adhesive layer were performed.

[Comparative Example 2]
(Preparation of modified acrylic polymer)
In Example 1, except having not used 4-hydroxybutyl acrylate, operation similar to Example 1 was performed and the modified (meth) acrylic-type polymer (b4) solution was prepared.

(Preparation of adhesive layer)
An acrylic pressure-sensitive adhesive solution (4) in which 0.2 parts by weight of dibenzoyl peroxide (1 minute half-life: 130 ° C.) is blended as a crosslinking agent with respect to 100 parts by weight of the solid content of the modified acrylic polymer (b4) solution. ) Was adjusted.

  Next, the acrylic pressure-sensitive adhesive solution (4) was applied to one side of a polyethylene terephthalate (PET) film (manufactured by Toray Industries, Inc., S-10, thickness: 38 μm), dried at 150 ° C. for 3 minutes, and dried. A pressure-sensitive adhesive layer having a thickness of 20 μm was formed. In addition, the decomposition rate of the peroxide at the time of drying at this time was 94 weight%. Moreover, the gel fraction (at room temperature for 5 days) and holding power (after storage at 80 ° C., room temperature × 5 days and 90 ° C. × 500 hours) of the pressure-sensitive adhesive layer were performed.

[Comparative Example 3]
(Preparation of modified acrylic polymer)
In Example 1, instead of 1 part by weight of 4-hydroxybutyl acrylate, the same operation as in Example 1 was performed except that 0.5 part by weight of 2-hydroxyethyl acrylate was used, and a modified (meth) acrylic polymer (B5) A solution was prepared.

(Preparation of adhesive layer)
An acrylic pressure-sensitive adhesive solution (5 containing 0.2 parts by weight of dibenzoyl peroxide (1 minute half-life: 130 ° C.) as a crosslinking agent with respect to 100 parts by weight of the solid content of the modified acrylic polymer (b5) solution. ) Was adjusted.

  Next, the acrylic pressure-sensitive adhesive solution (5) was applied to one side of a polyethylene terephthalate (PET) film (manufactured by Toray Industries Inc., S-10, thickness: 38 μm), dried at 150 ° C. for 3 minutes, and after drying A pressure-sensitive adhesive layer having a thickness of 20 μm was formed. In addition, the decomposition rate of the peroxide at the time of drying at this time was 92 weight%. Moreover, the gel fraction (at room temperature for 5 days) and holding power (after storage at 80 ° C., room temperature × 5 days and 90 ° C. × 500 hours) of the pressure-sensitive adhesive layer were performed.

  According to the said method, the measurement and evaluation of the adhesive layer produced in Examples 1-3 and Comparative Examples 1-3 were performed. The obtained results are shown in Table 1.

Example 4
(Preparation of adhesive layer)
0.15 parts by weight of trimethylolpropane / hexamethylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HL) is added as a crosslinking agent to 100 parts by weight of the solid content of the modified acrylic polymer (b2) solution. A prepared acrylic pressure-sensitive adhesive solution (6) was prepared.

  Next, the acrylic pressure-sensitive adhesive solution (6) was applied to one side of a polyethylene terephthalate (PET) film (manufactured by Toray Industries, Inc., S-10, thickness: 38 μm), dried at 120 ° C. for 3 minutes, after drying A pressure-sensitive adhesive layer having a thickness of 20 μm was formed.

Example 5
(Preparation of adhesive layer)
Styrene tackifier (softening point: 72-77 ° C., weight average molecular weight: 1300, refractive index: 1.59, manufactured by Eastman Chemical Co., Ltd.) with respect to 100 parts by weight of the solid content of the modified acrylic polymer (b2) solution. An acrylic pressure-sensitive adhesive solution (7) containing 50 parts by weight of Picolastic A75) and 0.2 parts by weight of a trimethylolpropane / hexamethylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HL) as a crosslinking agent. It was adjusted.

  Next, the acrylic pressure-sensitive adhesive solution (7) was applied to one side of a polyethylene terephthalate (PET) film (manufactured by Toray Industries Inc., S-10, thickness: 38 μm), dried at 120 ° C. for 3 minutes, and after drying A pressure-sensitive adhesive layer having a thickness of 20 μm was formed.

[Comparative Example 4]
(Preparation of adhesive layer)
Trimethylolpropane / hexamethylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HL) 0.15 parts by weight was blended as a crosslinking agent with respect to 100 parts by weight of the solid content of the acrylic polymer (a2) solution. An acrylic pressure-sensitive adhesive solution (8) was prepared.

  Next, the acrylic pressure-sensitive adhesive solution (8) was applied to one side of a polyethylene terephthalate (PET) film (manufactured by Toray Industries Inc., S-10, thickness: 38 μm), dried at 120 ° C. for 3 minutes, and after drying A pressure-sensitive adhesive layer having a thickness of 20 μm was formed.

[Comparative Example 5]
(Preparation of adhesive layer)
With respect to 100 parts by weight of the solid content of the acrylic polymer (a2) solution, a styrene tackifier (softening point: 72-77 ° C., weight average molecular weight: 1300, refractive index: 1.59, manufactured by Eastman Chemical Co., Ltd., Prepare an acrylic pressure-sensitive adhesive solution (9) containing 50 parts by weight of picolastic A75) and 0.2 parts by weight of a trimethylolpropane / hexamethylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HL) as a crosslinking agent. did.

  Next, the acrylic pressure-sensitive adhesive solution (9) was applied to one side of a polyethylene terephthalate (PET) film (manufactured by Toray Industries Inc., S-10, thickness: 38 μm), dried at 120 ° C. for 3 minutes, and after drying A pressure-sensitive adhesive layer having a thickness of 20 μm was formed.

  Samples on which the pressure-sensitive adhesive layers prepared in Examples 4 and 5 and Comparative Examples 4 and 5 were laminated were cut into a width of 20 mm and pasted on a non-alkali glass plate by one reciprocating roll of 2 Kg, 50 ° C., 0. After treating for 30 minutes in a 5 Mpa autoclave, the film was allowed to stand at 23 ° C. × 50% for 3 hours, and the peel adhesion was measured at a peel angle of 90 ° and a peel speed of 300 m / min. Further, after being stored at 60 ° C. for a predetermined time in a state of being attached to a glass plate, it is taken out and left for 3 hours under the condition of 23 ° C. × 50%. What was measured was measured as adhesive strength after storage. The obtained results are shown in FIG.

Example 6
(Preparation of acrylic polymer)
In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, and condenser, n-butyl acrylate 82.5 parts by weight, 4-hydroxybutyl acrylate 2 parts by weight, 2-ethylhexyl acrylate 15 parts by weight, acrylic Charge 0.5 parts by weight of acid, 0.1 part by weight of 2,2′-azobisisobutyronitrile as a polymerization initiator, and 200 parts by weight of ethyl acetate. After the substitution, a polymerization reaction was carried out for 15 hours while maintaining the liquid temperature in the flask at around 55 ° C. to prepare an acrylic polymer (a10) solution. The acrylic polymer (a10) had a weight average molecular weight of 1,840,000 and Tg of 221K.

(Preparation of modified acrylic polymer)
A four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a cooler, 400 parts by weight of the acrylic polymer (a10) solution diluted with ethyl acetate and diluted to 25% by weight, styrene (Tg: 373K) ) 40 parts by weight and 0.2 parts by weight of dibenzoyl peroxide as a polymerization initiator were introduced, nitrogen gas was introduced while gently stirring, and the atmosphere was sufficiently replaced with nitrogen. Then, the liquid temperature in the flask was kept at around 65 ° C. For 6 hours at 70 ° C. for 6 hours to prepare a modified acrylic polymer (b10) solution.

(Preparation of adhesive layer)
For 100 parts by weight of the solid content of the modified acrylic polymer (b10) solution, styrene tackifier (softening point: 82-85 ° C., refractive index: 1.60, Mw: 1380, manufactured by Yashara Chemical Co., SX-85) ) 60 parts by weight, 0.05 parts by weight of trimethylolpropane / tolylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate L) as a crosslinking agent, dibenzoyl peroxide (1 minute half-life: 130 ° C.) 0 An acrylic pressure-sensitive adhesive solution (10) containing 2 parts by weight and 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane was prepared.

  Next, the acrylic pressure-sensitive adhesive solution (10) was applied to one side of a polyethylene terephthalate (PET) film (Toray Industries, S-10, thickness: 25 μm), dried at 150 ° C. for 3 minutes, and after drying A pressure-sensitive adhesive layer having a thickness of 20 μm was formed. In addition, the decomposition rate of the peroxide at the time of drying at this time was 93 weight%.

Example 7
(Preparation of modified acrylic polymer)
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 400 parts by weight of the acrylic polymer (a10) solution diluted with ethyl acetate and diluted to 25% by weight, 48 parts by weight of styrene, After charging 2 parts by weight of 4-hydroxybutyl acrylate (Tg: 366K) and 0.2 parts by weight of dibenzoyl peroxide as a polymerization initiator, nitrogen gas was introduced while gently stirring, and the inside of the flask was sufficiently purged with nitrogen. The polymerization temperature was kept at around 65 ° C. for 6 hours and at 70 ° C. for 6 hours to prepare a modified acrylic polymer (b11) solution.

(Preparation of adhesive layer)
For 100 parts by weight of the solid content of the modified acrylic polymer (b11) solution, styrene tackifier (softening point: 82-85 ° C., refractive index: 1.60, Mw: 1380, manufactured by Yashara Chemical Co., SX-85 ) 60 parts by weight, 0.05 parts by weight of trimethylolpropane / tolylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate L) as a crosslinking agent, dibenzoyl peroxide (1 minute half-life: 130 ° C.) 0 An acrylic pressure-sensitive adhesive solution (11) containing 2 parts by weight and 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane was prepared.

  Next, the acrylic pressure-sensitive adhesive solution (11) was applied to one side of a polyethylene terephthalate (PET) film (manufactured by Toray Industries Inc., S-10, thickness: 25 μm), dried at 150 ° C. for 3 minutes, and after drying A pressure-sensitive adhesive layer having a thickness of 20 μm was formed. In addition, the decomposition rate of the peroxide at the time of drying at this time was 93 weight%.

Example 8
(Preparation of acrylic polymer)
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube and a condenser, 75 parts by weight of n-butyl acrylate, 1 part by weight of 4-hydroxybutyl acrylate, 23 parts by weight of isooctyl acrylate, 1 part by weight of acrylic acid Then, 0.1 part by weight of 2,2′-azobisisobutyronitrile and 200 parts by weight of ethyl acetate were charged as a polymerization initiator, and nitrogen gas was introduced while gently stirring, followed by thorough nitrogen substitution. The polymerization temperature was kept at around 55 ° C. for 15 hours to prepare an acrylic polymer (a12) solution. The acrylic polymer (a12) had a weight average molecular weight of 1,800,000 and a Tg of 217K.

(Preparation of modified acrylic polymer)
A four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a cooler, 400 parts by weight of the above-mentioned acrylic polymer (a12) solution diluted with ethyl acetate to 25% by weight, isobornyl acrylate 25 Part by weight (Tg: 370 K), 0.1 part by weight of dibenzoyl peroxide as a polymerization initiator were charged, nitrogen gas was introduced while gently stirring, and the atmosphere was sufficiently purged with nitrogen. The polymerization reaction was carried out for 6 hours at 70 ° C. while maintaining the temperature in the vicinity to prepare a modified acrylic polymer (b12) solution.

(Preparation of adhesive layer)
Copolymer of α-methylstyrene and styrene (softening point: 82-88 ° C., refractive index: 1.61, Mw: 1200, yeast based on 100 parts by weight of the solid content of the modified acrylic polymer (b12) solution Manchemical Co., Ltd., Crystallex 3085) 40 parts by weight, trimethylolpropane / tolylene diisocyanate trimer adduct (Nihon Polyurethane Kogyo Co., Ltd., Coronate L) 0.05 part by weight as a crosslinking agent, dibenzoyl peroxide (1 An acrylic pressure-sensitive adhesive solution (12) containing 0.2 part by weight of a half-life of 130 minutes at 130 ° C. and 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane was prepared.

  Next, the acrylic pressure-sensitive adhesive solution (12) was applied to one side of a polyethylene terephthalate (PET) film (manufactured by Toray Industries, Inc., S-10, thickness: 25 μm), dried at 150 ° C. for 3 minutes, and after drying A pressure-sensitive adhesive layer having a thickness of 20 μm was formed. In addition, the decomposition rate of the peroxide at the time of drying at this time was 93 weight%.

Example 9
(Preparation of adhesive layer)
In Example 6, except for not using a styrene tackifier, the same operation as Example 6 was performed and the acrylic adhesive solution (13) was adjusted.

  Next, the acrylic pressure-sensitive adhesive solution (13) was applied to one side of a polyethylene terephthalate (PET) film (manufactured by Toray Industries Inc., S-10, thickness: 25 μm), dried at 150 ° C. for 3 minutes, and after drying A pressure-sensitive adhesive layer having a thickness of 20 μm was formed. In addition, the decomposition rate of the peroxide at the time of drying at this time was 93 weight%.

Example 10
(Preparation of acrylic polymer)
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube and a condenser, n-butyl acrylate 70 parts by weight, 6-hydroxyhexyl acrylate 1 part by weight, acrylic acid 0.5 part by weight, 2-ethylhexyl Charge 28.5 parts by weight of acrylate, 0.1 part by weight of 2,2′-azobisisobutyronitrile as a polymerization initiator, and 200 parts by weight of ethyl acetate. After the replacement, the temperature of the liquid in the flask was kept at around 55 ° C., and a polymerization reaction was carried out for 15 hours to prepare an acrylic polymer (a14) solution. The acrylic polymer (a14) had a weight average molecular weight of 1,700,000 and Tg of 221K.

(Preparation of modified acrylic polymer)
400 parts by weight of the above acrylic polymer (a14) solution diluted with ethyl acetate to 25% by weight in a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, and 30 weights of phenoxyethyl acrylate Parts, 4-hydroxyethyl acrylate 2 parts by weight (Tg: 250K), 0.1 parts by weight of dibenzoyl peroxide as a polymerization initiator, and after sufficiently introducing nitrogen gas while gently stirring, The polymerization temperature was kept at around 65 ° C. for 6 hours, and the polymerization reaction was carried out at 70 ° C. for 6 hours to prepare a modified acrylic polymer (b14) solution.

(Preparation of adhesive layer)
For 100 parts by weight of the solid content of the modified acrylic polymer (b14) solution, styrene tackifier (softening point: 82-85 ° C., refractive index: 1.60, Mw: 1380, manufactured by Yashara Chemical Co., SX-85) ) 30 parts by weight, trimethylolpropane / hexamethylene diisocyanate trimer adduct (Nihon Polyurethane Kogyo Co., Ltd., Coronate HL) as a crosslinking agent 0.05 part by weight, dibenzoyl peroxide (1 minute half-life: 130 ° C.) 0 An acrylic pressure-sensitive adhesive solution (14) containing 2 parts by weight and 0.1 part by weight of N-phenyl-γ-aminopropyltrimethoxysilane was prepared.

  Next, the acrylic pressure-sensitive adhesive solution (14) was applied to one side of a polyethylene terephthalate (PET) film (manufactured by Toray Industries Inc., S-10, thickness: 25 μm), dried at 150 ° C. for 3 minutes, and after drying A pressure-sensitive adhesive layer having a thickness of 20 μm was formed. In addition, the decomposition rate of the peroxide at the time of drying at this time was 93 weight%.

Example 11
(Preparation of modified acrylic polymer)
A four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a cooler, 400 parts by weight of the acrylic polymer (a14) solution diluted with ethyl acetate and diluted to 25% by weight, 30 parts by weight of benzyl acrylate , 2-hydroxyethyl acrylate 2 parts by weight (Tg: 276 K), 0.1 parts by weight of dibenzoyl peroxide as a polymerization initiator were charged, nitrogen gas was introduced while gently stirring, and the flask was sufficiently purged with nitrogen. The polymerization temperature was kept at around 65 ° C. for 6 hours and at 70 ° C. for 6 hours to prepare a modified acrylic polymer (b15) solution.

(Preparation of adhesive layer)
For 100 parts by weight of the solid content of the modified acrylic polymer (b15) solution, styrene tackifier (softening point: 82-85 ° C., refractive index: 1.60, Mw: 1380, manufactured by Yashara Chemical Co., SX-85 ) 40 parts by weight, trimethylolpropane / hexamethylene diisocyanate trimer adduct (Nihon Polyurethane Industry Co., Ltd., Coronate HL) 0.05 part by weight, dibenzoyl peroxide (1 minute half-life: 130 ° C.) 0 An acrylic pressure-sensitive adhesive solution (15) containing 2 parts by weight and 0.1 part by weight of N-phenyl-γ-aminopropyltrimethoxysilane was prepared.

  Next, the acrylic pressure-sensitive adhesive solution (15) was applied to one side of a polyethylene terephthalate (PET) film (manufactured by Toray Industries Inc., S-10, thickness: 25 μm), dried at 150 ° C. for 3 minutes, and after drying A pressure-sensitive adhesive layer having a thickness of 20 μm was formed. In addition, the decomposition rate of the peroxide at the time of drying at this time was 93 weight%.

  According to the above method, the gel fraction, adhesive strength, holding power, refractive index, and haze value of the produced adhesive sheet were measured and evaluated. The obtained results are shown in Table 2.

  From the results of Table 2 above, it was found that when the pressure-sensitive adhesive layer prepared according to the present invention was used (Examples 6 to 11), the adhesiveness, durability, and optical properties were excellent in any of the Examples. .

The graph which shows the time-dependent change of the peeling adhesive force in an Example.

Claims (11)

As a monomer unit, a (meth) acrylic monomer represented by the general formula CH ₂ ═C (R ¹ ) COOC _n H _2n OH (where R ¹ is hydrogen or a methyl group, and n is an integer of 4 to 10). Monomer (a) 10 to 10 parts by weight of (meth) acrylic polymer (A) containing 0.2 to 10% by weight of homopolymer having a glass transition temperature (Tg) higher than Tg of (A) polymer. 200 parts by weight and a step of preparing a modified (meth) acrylic polymer (B) to be a base polymer by blending and polymerizing 0.02 to 5 parts by weight of a peroxide ;
The weight of the base polymer 100 parts by weight, the crosslinking agent contains 0.01 to 2 parts by weight, further, a layer in which the refractive index is a viscous Chakuzai composition you a tackifier of 1.51 to 1.75, Forming on one or both sides of the support;
And a step of forming a pressure-sensitive adhesive layer by crosslinking a layer made of the pressure-sensitive adhesive composition. The method for producing a pressure-sensitive adhesive layer according to claim 1, wherein the homopolymer has a glass transition temperature (Tg) of 300 K or more . The manufacturing method of the adhesive layer of Claim 1 or 2 whose glass transition temperature of the said (meth) acrylic-type polymer (A) is 250K or less . In the monomer (a), it is represented by the general formula CH ₂ ═C (R ¹ ) COOC _n H _2n OH (where R ¹ is hydrogen or a methyl group, and n is an integer of 4 to 10) ( The manufacturing method of the adhesive layer in any one of Claims 1-3 in which 1-15 weight% of (meth) acrylic-type monomers are contained . The said monomer (a) contains the monomer which has an aromatic ring, The manufacturing method of the adhesive layer in any one of Claims 1-4 . The manufacturing method of the adhesive layer in any one of Claims 1-5 which contain 10-100 weight part of tackifiers with respect to 100 weight part of said base polymers . The gel fraction of the said adhesive layer is 40 to 90 weight%, The manufacturing method of the adhesive layer in any one of Claims 1-6 . The haze value of the said adhesive layer is 30% or less, The manufacturing method of the adhesive layer in any one of Claims 1-7 . An optical member with an adhesive, wherein the adhesive layer obtained by the method for producing an adhesive layer according to any one of claims 1 to 8 is formed on one side or both sides of the optical member. The optical member with an adhesive according to claim 9, wherein the optical member is a microlens. An image display device using at least one optical member with an adhesive according to claim 9 or 10 .

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