JP5085077B2 - Adhesive composition, adhesive layer and method for producing the same, and optical member with adhesive - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive composition. Moreover, this invention relates to the adhesive layer formed with the said adhesive composition, 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, and those in which these are laminated. Examples of the image display device include a liquid crystal display device, an organic EL display device, and a PDP.

  An optical member used in the liquid crystal display device, such as a polarizing plate or a retardation plate, is attached to the liquid crystal cell using an adhesive. Such an optical material has a large expansion and contraction under conditions of heat and humidity, and the resulting floating and peeling easily occur, and the adhesive is required to have durability that can cope with this.

  Moreover, when affixing to a liquid crystal cell, various processing processes, such as a punching process and a slit process, are made in the state in which the adhesive was bonded to the optical member. At this time, the pressure-sensitive adhesive may be taken off by the cutting blade or protrude from the cut surface. Therefore, it is necessary to perform an aging treatment as a countermeasure, and the productivity is significantly hindered. That is, it is very advantageous in terms of productivity that such processing can be performed quickly after an optical member with an adhesive is manufactured.

  In addition, after attaching the optical film with adhesive to the liquid crystal cell, if the optical film is peeled off due to misalignment or biting of foreign matter, the liquid crystal cell may be destroyed or the gap may be changed. There is also a demand for re-peelability that can be easily removed.

  As such an adhesive for optical members, adhesives having various compositions have been proposed so far. When optical members, liquid crystal panels, various light sources, diffusion plates, and the like are bonded together, the transparency and Acrylic adhesives are used because of their good weather resistance.

  For example, acrylic pressure-sensitive adhesives grafted with polydimethylsiloxane have been disclosed so far (see, for example, Patent Document 1).

  Further, the refractive index of the optical member is usually 1.52 to 1.55 for glass, 1.54 for polycarbonate, and about 1.50 for triacetyl cellulose, and the refractive index of acrylic adhesive is about 1.47. Since there is a large difference, a difference in refractive index occurs at the interface between the optical member and the pressure-sensitive adhesive. When light enters at a shallow angle, there is a problem that effective use of light is hindered.

  In order to solve such problems, various attempts have been made to create an acrylic pressure-sensitive adhesive having a high refractive index. Such attempts can be broadly divided into a method of using an acrylic copolymer having a high refractive index by copolymerizing a high refractive index monomer as a base polymer of an acrylic pressure-sensitive adhesive, and an ordinary acrylic polymer having a low refractive index. A method of increasing the refractive index of an acrylic pressure-sensitive adhesive by adding a refractive index adjusting agent to a copolymer has been studied.

  For example, as an example of the former, an acrylic adhesive having a refractive index of 1.48 or more using an acrylic copolymer obtained by copolymerizing a monomer having an aromatic group substituted or not substituted with bromine as a base polymer. An agent is disclosed (for example, see Patent Document 2). Further, an acrylic pressure-sensitive adhesive having a refractive index of 1.49 to 1.60 using an acrylic copolymer copolymerized with an aromatic group-containing monomer is disclosed as a base polymer (see, for example, Patent Document 3). . Further, an acrylic pressure-sensitive adhesive having a refractive index of 1.50 to 1.55 using an acrylic copolymer obtained by copolymerizing 40 to 90% by weight of an aromatic group monomer is disclosed (for example, see Patent Document 4). . In addition, a high refractive index polymer obtained by copolymerizing a monomer introduced with an aromatic ring or bromine is described (for example, see Non-Patent Document 1).

  On the other hand, as the latter example, an acrylic pressure-sensitive adhesive to which a tackifier is added in order to adjust the refractive index and adhesive strength of the pressure-sensitive adhesive is disclosed (for example, see Patent Documents 5 and 6). An acrylic pressure-sensitive adhesive in which a styrene-based oligomer having a molecular weight of 900 or less is added as a refractive index adjusting agent to a polymer-based polymer is disclosed (for example, see Patent Document 7).

  However, the acrylic pressure-sensitive adhesives disclosed in these patent documents can reduce the total reflection of light at the interface with the optical member by increasing the refractive index. Since the characteristics deteriorated, the compatibility between the high refractive index and the adhesive characteristics was not fully satisfied.

  As in Patent Documents 2 to 4, in an acrylic copolymer obtained by copolymerizing a monomer having an aromatic ring, it is the copolymerization ratio that adjusts the refractive index, and the copolymer is used to increase the refractive index. As the polymerization ratio was increased, a trade-off phenomenon was observed in which the adhesive properties greatly decreased. For this reason, there is a natural limit to satisfy both the high refractive index and the adhesive property by the copolymerization ratio of the monomer having an aromatic ring. In order to increase the refractive index, a monomer substituted with bromine can be used as a monomer having an aromatic ring. However, from the viewpoint of environmental measures, the movement of non-halogen is active mainly in electrical and electronic applications, which is not preferable. In addition, in order to adjust the refractive index of the acrylic copolymer, there is a complication of changing the copolymerization ratio of the copolymer itself.

  On the other hand, in Patent Documents 5 to 6, there is an operational advantage that the refractive index can be adjusted simply by mixing a tackifier as a refractive index adjusting agent, but acrylic adhesives generally have poor compatibility with the tackifier. . For this reason, when a large amount of the refractive index adjusting agent is added, the acrylic pressure-sensitive adhesive becomes cloudy and the adhesive strength is lowered, so that the amount of use thereof is limited. Moreover, in patent document 7, the said compatibility is improved by using a low molecular weight refractive index regulator, and even if it adds much refractive index regulator, it does not become cloudy. However, in patent document 6, the problem that the adhesive characteristic (holding power, especially holding power in high temperature) of acrylic adhesive itself falls large also generate | occur | produces.

  Moreover, in patent document 1, since the method of copolymerizing what is called a macromer which has an acryloyl group or a methacryloyl group at the terminal of a graft chain, there also existed a problem that there were few degrees of freedom at the time of a polymer synthesis | combination.

  Furthermore, even if these technologies are used, there are many cases where the durability at higher temperatures is unsatisfactory, and the adverse effect on re-peelability due to an increase in adhesiveness, aging treatment before processing, etc. The development of a pressure-sensitive adhesive that can solve these various problems in a well-balanced manner is required.

JP-A-10-168407 Special table 2003-535921 gazette JP 2002-173656 A JP 2003-13029 A JP 2000-321960 A JP 2002-14225 A JP 2003-342546 A Yasuhiro Koike, “Optical Properties of Polymers” P11-13, Kyoritsu Shuppan (1994)

  Therefore, in order to cope with the above-mentioned problems, the present invention exhibits excellent adhesive properties after the crosslinking treatment, does not cause defects such as foaming, floating, and peeling in the heating test / humidification test, in durability and removability. An object of the present invention is to provide a pressure-sensitive adhesive composition for an optical member that is excellent and has a short time to processing, a relatively high refractive index, and little loss of light due to reflection.

  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-mentioned object, the present inventors diligently studied the constitution of the pressure-sensitive adhesive composition, and as a result, found the following pressure-sensitive adhesive composition and pressure-sensitive adhesive layer, and completed the present invention.

That is, the pressure-sensitive adhesive composition of the present invention is for an optical member,
As a monomer unit, a (meth) acrylic group represented by the general formula CH ₂ = C (R ¹ ) COOR ² (where R ¹ is hydrogen or a methyl group, and R ² is an alkyl group having 2 to 14 carbon atoms). With respect to 100 parts by weight of (meth) acrylic polymer (A) containing 50 to 98% by weight of monomer, the glass transition temperature (Tg) of the homopolymer is the glass transition temperature (Tg) of the (meth) acrylic polymer (A). A pressure-sensitive adhesive composition based on a modified (meth) acrylic polymer (B) obtained by blending and polymerizing 10 to 100 parts by weight of a higher monomer,
It contains 0.02 to 2 parts by weight of peroxide with respect to 100 parts by weight of the base polymer.

In addition, the method for producing the pressure-sensitive adhesive composition for optical members of the present invention,
A step of forming a layer made of the above-mentioned pressure-sensitive adhesive composition for optical members on one or both sides of a support, and a step of subjecting the layer made of the pressure-sensitive adhesive composition for optical members to a peroxide crosslinking treatment. And

  According to the present invention, as shown in the results of the examples, the pressure-sensitive adhesive composition containing a modified (meth) acrylic polymer (B) having a specific monomer composition, a specific amount of an isocyanate crosslinker and a peroxide is crosslinked. As a result, the pressure-sensitive adhesive layer has excellent re-peelability and workability, is excellent in durability and does not float or peel off due to heat treatment or high-humidity treatment, 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 above monomer is produced by polymerization reaction of the above monomer in the presence of the (meth) acrylic polymer (A), but the (meth) acrylic polymer (A) Graft polymerization is also considered to occur, and as a result, a polymer or domain composed of another monomer composition having a high glass transition temperature (Tg) exists uniformly in the (meth) acrylic polymer (A). It is considered to be in a state. By polymerizing such a modified (meth) acrylic polymer (B) with a specific amount of an isocyanate-based crosslinking agent and a peroxide, a polymer or domain comprising another monomer composition having a high glass transition temperature (Tg). As a result of good balance between main chain cross-linking (and strong urethane bond with isocyanate when used together with isocyanate), which is localized in the side chain and has a gentle interaction between the copolymers and excellent relaxation properties by peroxide It is presumed that the above characteristics are exhibited.

The modified (meth) acrylic polymer (B) in the present invention has a general formula CH ₂ ═C (R ¹ ) COOR ² (wherein R ¹ is hydrogen or a methyl group, R ² has 2 to 14 carbon atoms) as monomer units. The glass transition temperature (Tg) of the homopolymer is 100% by weight of the (meth) acrylic monomer (A) containing 50 to 98% by weight of the (meth) acrylic monomer represented by It is obtained by mixing and polymerizing 10 to 100 parts by weight of a monomer higher than the glass transition temperature (Tg) of the (meth) acrylic polymer (A). By using the modified (meth) acrylic polymer (B) as a base polymer, the pressure-sensitive adhesive composition of the present invention provides a pressure-sensitive adhesive layer that balances adhesiveness, durability, and improvement in refractive index in a balanced manner. Can do.

  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 0.02 to 2 parts by weight of a peroxide with respect to 100 parts by weight of the base polymer.

  The pressure-sensitive adhesive composition of the present invention preferably contains 0.02 to 2 parts by weight of an isocyanate-based crosslinking agent with respect to 100 parts by weight of the base polymer.

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

  Moreover, in the adhesive composition of this invention, it is preferable to contain 0.01-1 weight part of silane coupling agents with respect to 100 weight part of said base polymers.

  Furthermore, the (meth) acrylic polymer (A) contains 0.1-20% by weight of a hydroxyl group-containing monomer and 0.1-20% by weight of a carboxyl group-containing monomer as monomer units. It is preferable that By using the (meth) acrylic polymer (A) containing the above-mentioned specific amount of hydroxyl group-containing monomer and carboxyl group-containing monomer, even if the optical member is peeled off at the time of repair or recycling more reliably There can be no rest.

  The monomer is preferably a (meth) acrylic monomer having an aromatic group. By using such a monomer, it is possible to increase the refractive index and reduce the interface reflection more reliably.

  Furthermore, it is preferable to contain 10 to 100 parts by weight of a tackifier having an aromatic ring or a hydrogenated product thereof and a refractive index of 1.51 to 1.75 with respect to 100 parts by weight of the base polymer. By using such a tackifier, the refractive index can be increased more reliably and the interface reflection can be reduced.

  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. A pressure-sensitive adhesive layer that does not occur, has excellent durability, and has an improved refractive index. 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 20% 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 any one of the above-mentioned pressure-sensitive adhesive compositions on one or both sides of a support, and a layer made of the pressure-sensitive adhesive composition is peroxidized. It can obtain by using the manufacturing method including the process of physical-crosslinking treatment. 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 pressure-sensitive adhesive layer obtained by the above production method, the gel fraction of the pressure-sensitive adhesive layer is preferably 40 to 90% by 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.

  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.

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

The pressure-sensitive adhesive composition of the present invention is for an optical member,
As a monomer unit, a (meth) acrylic group represented by the general formula CH ₂ = C (R ¹ ) COOR ² (where R ¹ is hydrogen or a methyl group, and R ² is an alkyl group having 2 to 14 carbon atoms). With respect to 100 parts by weight of (meth) acrylic polymer (A) containing 50 to 98% by weight of monomer, the glass transition temperature (Tg) of the homopolymer is the glass transition temperature (Tg) of the (meth) acrylic polymer (A). A pressure-sensitive adhesive composition based on a modified (meth) acrylic polymer (B) obtained by blending and polymerizing 10 to 100 parts by weight of a higher monomer,
It contains 0.02 to 2 parts by weight of peroxide with respect to 100 parts by weight of the base polymer.

In addition, the method for producing the pressure-sensitive adhesive composition for optical members of the present invention,
A step of forming a layer made of the above-mentioned pressure-sensitive adhesive composition for optical members on one or both sides of a support, and a step of subjecting the layer made of the pressure-sensitive adhesive composition for optical members to a peroxide crosslinking treatment. And

  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 ) COOR ² (where R ¹ is hydrogen or a methyl group, R ² is an alkyl group having 2 to 14 carbon atoms) (Meth) acrylic monomer represented by 50 to 98% by weight.

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 12 carbon atoms, and more preferably 4 to 9 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.

In the present invention, the above-mentioned (meth) acrylic monomer represented by the general formula CH ₂ ═C (R ¹ ) COOR ² may be used alone or in combination of two or more. The content as a whole is 50 to 98% by weight, preferably 60 to 98% by weight, and preferably 70 to 90% by weight in the whole monomer of the (meth) acrylic polymer (A). Is more preferable. When the (meth) acrylic monomer (A) is less than 50% by weight, the adhesiveness is poor, which is not preferable.

  The (meth) acrylic polymer (A) preferably contains 0.1 to 20% by weight of a hydroxyl group-containing monomer as a monomer unit, more preferably 0.2 to 10% by weight, still more preferably 0.2 to It contains 7% by weight. When the content of the hydroxyl group-containing monomer is within the above range, the cohesive force can be more sufficiently exhibited. On the other hand, when the content of the hydroxyl acid-containing monomer exceeds 20% by weight, the adhesiveness may be lowered. .

  The hydroxyl group-containing monomer means a polymerizable monomer having one or more hydroxyl groups in the monomer structure.

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxypropyl ( (Meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl Acrylate, N-methylol (meth) acrylamide, N-hydroxy (meth) acrylamide, vinyl alcohol, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl Ether, such as diethylene glycol monomethyl ether, and the like. Of these, 4-hydroxybutyl (meth) acrylate, 6-hydroxypropyl (meth) acrylate, and the like are preferable.

  The (meth) acrylic polymer (A) preferably contains 0.1 to 20% by weight of a carboxyl group-containing monomer as a monomer unit, more preferably 0.2 to 10% by weight, and still more preferably 0. 0.5 to 7% by weight. When the content of the carboxyl group-containing monomer is within the above range, foaming and peeling are less likely to occur in durability tests such as high temperature and high humidity, while the content of the carboxyl group-containing monomer is 20 If it exceeds% by weight, there may be a problem that the adhesiveness is lowered or the viscosity becomes high and the productivity is reduced.

  The carboxyl group-containing monomer is a polymerizable monomer having one or more carboxyl groups in the monomer structure.

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

  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. It 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 (A) of the present invention include sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, cyano group-containing monomers, vinyl ester monomers, and aromatic vinyl monomers. Cohesive strength / heat resistance improving component such as amide group-containing monomer, amino group-containing monomer, imide group-containing monomer, epoxy group-containing monomer, and vinyl ether monomer Components and the like can be used as appropriate. These monomer compounds may be used alone or in admixture of two or more.

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

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

  The above other polymerizable monomers may be used alone or in combination of two or more, but the total content is in the whole monomer of the (meth) acrylic polymer (A). 0 to 50% by weight, more preferably 0 to 35% by weight, and further preferably 0 to 25% by weight.

  Among them, the total amount of the amino group-containing monomer, imide group-containing monomer, or amide group-containing monomer as the polymerizable monomer is 0.1 to 20% by weight in the whole monomer of the (meth) acrylic polymer (A). It is preferably 0.5 to 15% by weight, more preferably 2 to 10% by weight. If the amino group-containing monomer, imide group-containing monomer, or amide group-containing monomer is within the above range, adverse effects on adhesion and durability can be more reliably suppressed, such as peeling due to high temperature and high humidity. If the content is too much, the adhesiveness may decrease. These may be used singly or in combination of two or more.

  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, it is desirable that the glass transition temperature (Tg) of the (meth) acrylic polymer (A) is −5 ° C. or lower, preferably −10 ° C. or lower, because the adhesive performance is easily balanced. When the glass transition temperature is higher than −5 ° C., the polymer is difficult to flow, and the adherend is insufficiently wetted, which may cause blisters generated between layers. In addition, the glass transition temperature (Tg) of (meth) acrylic-type polymer (A) can be adjusted in the said range by changing the monomer component and composition ratio to be used suitably.

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

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

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

  The monomer is appropriately used as long as it is 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. it can. Among these, it is preferable to use a monomer having an aromatic group. These may be used singly or in combination of two or more.

  Examples of the (meth) acrylic monomer having an aromatic group include styrene monomers such as styrene and α-methylstyrene, vinyltoluene monomers such as vinyltoluene and αvinyltoluene, benzyl (meth) acrylate, Examples thereof include (meth) acrylic monomers having an aromatic group such as naphthyl (meth) acrylate, phenoxyethyl (meth) acrylate, and phenoxybutyl (meth) acrylate.

  In addition, as a method for polymerizing the monomer, in the case of solution polymerization, after adding a necessary monomer and a solvent whose viscosity is adjusted to a solution of the (meth) acrylic polymer (A), and then substituting with nitrogen. And a method of adding a polymerization initiator such as 2,2′-azobisisobutyronitrile and dibenzoyl peroxide and heating at 50 ° C. to 80 ° C. for 4 to 15 hours to terminate the reaction. it can. 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. After absorbing the monomer into the (meth) acrylic polymer particles, add an aqueous solution of a water-soluble azo compound or ammonium persulfate, and heat at 50 to 80 ° C. for 4 to 15 hours to complete the reaction. The method of making it can be given.

  In the present invention, the monomer is polymerized by blending 10 to 100 parts by weight with respect to 100 parts by weight of the (meth) acrylic polymer (A), but is polymerized by blending 15 to 70 parts by weight. It is preferable that 20 to 60 parts by weight is blended and the polymerization is more preferable, and 20 to 50 parts by weight is blended and polymerization is particularly preferable. 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.

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

  The pressure-sensitive adhesive composition of the present invention contains a peroxide.

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

  Examples of the 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 peroxide (1 minute half-life temperature: 116.4 ° C.), di-n-octanoyl peroxide (1 minute half-life temperature: 117.4 ° C.), 1,1,3,3-tetramethylbutyl Oxy-2-ethylhexanoate (1 minute half-life temperature: 124.3 ° C), di (4-methylbenzoyl) peroxide (1 minute half-life temperature: 128.2 ° C), dibenzoyl peroxide (half-minute for 1 minute) Period temperature: 130.0 ° C.), t-butyl peroxyisobutyrate (1 minute half-life temperature: 136.1 ° C.), 1,1-di (t-hexylperoxy) cyclohexane (1 minute half-life temperature: 149.2 ° C.). Especially, since the crosslinking reaction efficiency is excellent, di (4-t-butylcyclohexyl) peroxydicarbonate (1 minute half-life temperature: 92.1 ° C.), dilauroyl peroxide (1 minute half-life temperature: 116. 4 ° C), dibenzoyl peroxide (1 minute half-life temperature: 130.0 ° C) and the like are preferably used.

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

  The peroxide may be used alone, or two or more kinds may be mixed and used, but the total content is 0.1% of the peroxide with respect to 100 parts by weight of the base polymer. The content is preferably 02 to 2 parts by weight, more preferably 0.04 to 1.5 parts by weight, and even more preferably 0.05 to 1 part 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 peroxide decomposition amount which remained after the reaction process, it can measure by HPLC (high performance liquid chromatography), for example.

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

  In addition, the pressure-sensitive adhesive composition of the present invention preferably contains an isocyanate-based crosslinking agent for the purpose of further improving adhesive strength and durability.

  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.) And polyisocyanates polyfunctionalized with allophanate bonds.

  The isocyanate-based crosslinking agent may be used alone or in combination of two or more, but the total content is 100 parts by weight of the base polymer with respect to the isocyanate-based crosslinking agent. It is preferable to contain 0.02 to 2 parts by weight, more preferably 0.04 to 1.5 parts by weight, and even more preferably 0.05 to 1 part by weight. By using an isocyanate-based crosslinking agent in the above range, the cohesive strength and durability can be more reliably improved. On the other hand, when the amount exceeds 2 parts by weight, crosslinking is excessive and the adhesiveness is poor. There is a case.

  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.

  In the present invention, the amount of crosslinking agent (peroxide and isocyanate crosslinking agent when combined with an isocyanate crosslinking agent) added so that the gel fraction of the crosslinked pressure-sensitive adhesive layer is 40 to 90% by weight. It is preferable to adjust the amount of the crosslinking agent so that it is 50 to 85% by weight, and it is more preferable to adjust the amount of the crosslinking agent to be 55 to 80% by weight. Further preferred. When the gel fraction is smaller than 40% by weight, the cohesive force is reduced, so that the durability may be inferior, and when it exceeds 90% by weight, the adhesiveness may be inferior. Furthermore, the cross-linking ratio between the two 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 the peroxide and the 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.

  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-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1,3- Amino group-containing silane coupling agents such as dimethylbutylidene) propylamine, (meth) acryl group-containing silane coupling agents such as 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-isocyanatopropyl Triethoxysilane etc. Such Inshianeto group-containing silane coupling agent. 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 modified (meth) acrylic polymer (B) has a refractive index of 1.49 to 1.54 because 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 that the content of the tackifier whose softening point is 40 ° C. or less. Furthermore, it is preferable that it is 60 degreeC or more and 70-160 degreeC. When using a tackifier with a softening point of less than 40 ° C., the amount used is less than 20 parts by weight and used in combination with a tackifier with a softening point of 50 ° C. or more. It is preferable from the viewpoint of heat resistance that the temperature is 40 ° C or higher.

  Further, the tackifier preferably has a weight average molecular weight of 300 to 7000, more preferably 400 to 6000, and still more preferably 420 to 6000.

  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 adhesive properties are deteriorated, which is not preferable.

  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 subjecting a product to crosslinking. By using such a production method, the above-mentioned excellent adhesive properties, in particular, even when the adhesive layer is thinned, an adhesive having excellent durability that does not float or peel off due to heat treatment or high-humidity treatment. An agent layer can be obtained.

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

  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 carry out antistatic treatment such as. In particular, when the surface of the separator is appropriately subjected to a release treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment, the peelability from the pressure-sensitive adhesive layer can be further improved.

  In the above production method, the release-treated sheet can be used as it is as a separator such as an adhesive sheet or an optical member with an adhesive, and the process can be simplified.

  The pressure-sensitive adhesive layer in the present invention requires aging after these properties have undergone coating, drying, crosslinking, and transfer processes by crosslinking the above-mentioned pressure-sensitive adhesive composition with the above-mentioned crosslinking agent and peroxide. Therefore, the pressure-sensitive adhesive layer is excellent in productivity that punching and slitting can be performed quickly.

  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 20% or less, more preferably 19% or less, and further preferably 18% or less. If the haze value exceeds 20%, the transmittance is greatly reduced when laminated on the 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 do so, even if it is phase-separated, since the domain is small, 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.

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

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

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

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

  Instead of the method of directly applying the reflecting plate to the transparent protective film of the polarizing plate, the reflecting plate can be used as a reflecting sheet provided with a reflecting layer on an appropriate film according to the transparent film. Since the reflective layer is usually made of metal, the usage form in which the reflective surface is covered with a transparent protective film, a polarizing plate, etc. prevents the decrease in reflectance due to oxidation, and thus the long-term sustainability of the initial reflectance. In addition, it is more preferable to avoid a separate attachment of the protective layer.

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

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

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

  Examples of the retardation plate include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, a liquid crystal polymer alignment film, and a liquid crystal polymer alignment layer supported by a film. The thickness of the retardation plate is not particularly limited, but is generally about 20 to 150 μm.

  Examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polycarbonate, polyarylate, polysulfone, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, Polyphenylene sulfide, polyphenylene oxide, polyallylsulfone, polyvinyl alcohol, polyamide, polyimide, polyolefin, polyvinyl chloride, cellulose polymer, norbornene resin, or binary, ternary various copolymers, graft copolymers Examples thereof include polymers and blends. These polymer materials become oriented products (stretched films) by stretching or the like.

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

  The retardation plate may have an appropriate retardation according to the purpose of use, such as for the purpose of compensating for coloring or viewing angle due to birefringence of various wavelength plates and liquid crystal layers, for example. In this case, the retardation plate may be laminated to control optical characteristics such as retardation.

  The elliptical polarizing plate and the reflective elliptical polarizing plate are obtained by laminating a polarizing plate or a reflective polarizing plate and a retardation plate in an appropriate combination. Such an elliptically polarizing plate can also be formed by sequentially laminating them 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 superimposition method. 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 between 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.
・ Apparatus: 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 optical film with pressure-sensitive adhesive (width 25 mm) obtained in Examples and Comparative Examples was attached to acrylic-free glass (Corning Corp., # 1737, thickness: 0.7 mm) by reciprocating 1 roll 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.

  Further, after the above autoclave treatment, it was stored at 70 ° C. for 6 hours, left in an atmosphere of 23 ° C. × 50% RH for 3 hours, and then measured for peel adhesion at a peel angle of 90 ° and a peel speed of 300 mm / min. Was the adhesive strength after heating.

<Durability evaluation>
The optical film with pressure-sensitive adhesive (12 inch size) obtained in Examples and Comparative Examples was attached to acrylic-free glass (Corning Corp., # 1737, thickness: 0.7 mm) by reciprocating 1 roll with a 2 kg roller. did. Then, after processing for 30 minutes in an autoclave at 50 ° C. and 0.5 Mpa, the sample was stored in an atmosphere at 100 ° C. for 300 hours, and durability was evaluated using the sample. The durability is evaluated visually, and the evaluation criteria are as follows.
・ If the optical member does not float or peel: ○
When the optical member is lifted or peeled off: x.

<Evaluation of workability>
The optical films with pressure-sensitive adhesives obtained in Examples and Comparative Examples were punched using a press machine without performing an aging treatment, and processability was evaluated. The workability is evaluated visually, and the evaluation criteria are as follows.
・ If the adhesive layer is not removed on the cutting blade: ○
・ If the adhesive layer is removed or attached to the cutting blade: x.

<Measurement of refractive index>
Under an atmosphere of 25 ° C., sodium D-rays were 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.

<Preparation of (meth) acrylic polymer>
[Acrylic polymer (a1)]
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube and a condenser, 97.5 parts by weight of n-butyl acrylate, 2 parts by weight of acrylic acid, 0.5 part by weight of 4-hydroxybutyl acrylate, 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.

[Modified acrylic polymer (b1)]
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a cooler, 500 parts by weight of the acrylic polymer (a1) solution diluted with ethyl acetate and diluted to 25% by weight, 20 parts by weight of styrene, Charged 0.05 parts by weight of 2,2′-azobisisobutyronitrile as a polymerization initiator, introduced nitrogen gas with gentle stirring and sufficiently purged with nitrogen, and then the liquid temperature in the flask was around 65 ° C. The polymer was subjected to a polymerization reaction for 10 hours to prepare a modified acrylic polymer (b1) solution.

[Acrylic polymer (a2)]
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube and a condenser, 2-ethylhexyl acrylate 48 parts by weight, n-butyl acrylate 50 parts by weight, acrylic acid 1 part by weight, 4-hydroxybutyl acrylate 1 Part by weight, 0.12 part by weight of 2,2′-azobisisobutyronitrile as a polymerization initiator and 200 parts by weight of ethyl acetate were introduced, nitrogen gas was introduced while gently stirring, and the nitrogen was sufficiently substituted. The polymerization temperature was kept at around 55 ° C. for 15 hours to prepare an acrylic polymer (a2) solution. The acrylic polymer (a2) had a weight average molecular weight of 1,720,000.

[Modified acrylic polymer (b2)]
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a condenser, 500 parts by weight of the acrylic polymer (a2) solution diluted with ethyl acetate and diluted to 25% by weight, 20 parts by weight of styrene, Charged 0.05 parts by weight of 2,2′-azobisisobutyronitrile as a polymerization initiator, introduced nitrogen gas with gentle stirring and sufficiently purged with nitrogen, and then the liquid temperature in the flask was around 65 ° C. The polymer was subjected to a polymerization reaction for 10 hours to prepare a modified acrylic polymer (b2) solution.

[Acrylic polymer (a3)]
In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, and condenser, 93.5 parts by weight of n-butyl acrylate, 4 parts by weight of acryloylmorpholine, 2 parts by weight of acrylic acid, 4-hydroxybutyl acrylate 0.5 parts by weight, 2,2′-azobisisobutyronitrile 0.1 part by weight as a polymerization initiator, and 200 parts by weight of ethyl acetate were charged, and nitrogen gas was introduced while gently stirring to fully replace the nitrogen. After that, a polymerization reaction was performed for 15 hours while maintaining the liquid temperature in the flask at around 55 ° C. to prepare an acrylic polymer (a3) solution. The acrylic polymer (a3) had a weight average molecular weight of 1.89 million.

[Modified acrylic polymer (b3)]
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a cooler, 500 parts by weight of the acrylic polymer (a3) solution diluted with ethyl acetate and diluted to 25% by weight, 30 parts by weight of styrene, Charged 0.05 parts by weight of 2,2′-azobisisobutyronitrile as a polymerization initiator, introduced nitrogen gas with gentle stirring and sufficiently purged with nitrogen, and then the liquid temperature in the flask was around 65 ° C. The polymer was subjected to a polymerization reaction for 10 hours to prepare a modified acrylic polymer (b3) solution.

[Acrylic polymer (a4)]
2-Ethylhexyl acrylate 50 parts by weight, n-butyl acrylate 48 parts by weight, acrylic acid 1 part by weight, 6-hydroxyhexyl acrylate 1 part by weight, reactive emulsifier (Daiichi Kogyo Seiyaku Co., Ltd., Aqualon HS-10) 2 parts by weight The emulsion (a) was obtained by emulsification with a homomixer in addition to 120 parts by weight of water to which parts were added. Next, a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a cooler was purged with nitrogen for 1 hour, and then the emulsion (a) and the polymerization initiator (Wako Pure Chemical Industries) were added to the four-necked flask. (VA-057), 0.03 part by weight, was added, and the polymerization temperature was maintained for 3.5 hours while maintaining the liquid temperature in the flask at around 56 ° C.

  In addition, 50 parts by weight of 2-ethylhexyl acrylate, 48 parts by weight of n-butyl acrylate, 1 part by weight of acrylic acid, and 1 part by weight of 6-hydroxyhexyl acrylate were used as reactive emulsifier (Daily Kogyo Seiyaku Co., Ltd., Aqualon HS-10). In addition to 30 parts by weight of water added with 2 parts by weight, the mixture was emulsified with a homomixer to obtain an emulsion (b). Next, the emulsion (b) was added dropwise to the four-necked flask over 2.5 hours while maintaining the liquid temperature in the flask at around 59 ° C. to conduct a polymerization reaction. After the polymerization reaction, ammonia was added to adjust the pH to 8 to prepare an acrylic polymer (a4) solution.

[Modified acrylic polymer (b4)]
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a cooler, 100 parts by weight of the acrylic polymer (a4) solution (solid concentration 57% by weight), 13 parts by weight of water, and 17 parts by weight of styrene Part was charged and the atmosphere was purged with nitrogen for 1 hour, and then styrene was absorbed into the (meth) acrylic polymer (a4) particles. Next, 0.03 part by weight of a polymerization initiator (VA-057, manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the polymerization temperature was kept at around 60 ° C. for 4 hours to carry out a polymerization reaction, and the modified acrylic polymer (b4) An aqueous dispersion was prepared.

[Modified acrylic polymer (b5)]
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 500 parts by weight of the acrylic polymer (a1) solution diluted with ethyl acetate and diluted to 25% by weight, 50 parts by weight of styrene, Charged 0.05 parts by weight of 2,2′-azobisisobutyronitrile as a polymerization initiator, introduced nitrogen gas with gentle stirring and sufficiently purged with nitrogen, and then the liquid temperature in the flask was around 65 ° C. The polymer was subjected to a polymerization reaction for 10 hours to prepare a modified acrylic polymer (b5) solution.

[Example 1]
(Preparation of optical film with adhesive)
Addition of 0.3 part by weight of dibenzoyl peroxide (1 minute half-life: 130 ° C.) as a cross-linking agent and hexamethylene diisocyanate of trimethylolpropane to 100 parts by weight of the solid content of the modified acrylic polymer (b1) solution An acrylic pressure-sensitive adhesive solution (1) containing 0.06 part by weight of a polyisocyanate-based crosslinking agent (Mitsui Chemical Polyurethane, Takenate D160N) was prepared.

  Next, 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. The pressure-sensitive adhesive layer having a thickness of 20 μm after drying was formed.

  The pressure-sensitive adhesive layer was transferred to a polarizing film in which a triacetylcellulose film was bonded on both sides of a polyvinyl alcohol film dyed and stretched with iodine to prepare an optical film with a pressure-sensitive adhesive. At this time, the gel fraction of the pressure-sensitive adhesive layer was 80% by weight, and the decomposition rate of the peroxide during drying was 88% by weight.

[Example 2]
(Preparation of optical film with adhesive)
Copolymer of α-methylstyrene and styrene (softening point: 82-88 ° C., weight average molecular weight: 1200, refractive index: 1.61, relative to 100 parts by weight of the solid content of the modified acrylic polymer (b1) solution. Polyisocyanate comprising 40 parts by weight of Eastman Chemical Co., Ltd., Crystallex 3085), 0.4 parts by weight of dibenzoyl peroxide (1 minute half-life: 130 ° C.) as a crosslinking agent, and hexamethylene diisocyanate adduct of trimethylolpropane An acrylic pressure-sensitive adhesive solution (2) containing 0.1 part by weight of a cross-linking agent (manufactured by Mitsui Chemicals Polyurethanes, Takenate D160N) was prepared.

  Next, the acrylic pressure-sensitive adhesive solution (2) is applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester Film, thickness: 38 μm) and dried at 150 ° C. for 3 minutes. The pressure-sensitive adhesive layer having a thickness of 20 μm after drying was formed.

  The pressure-sensitive adhesive layer was transferred to a polarizing film in which a triacetylcellulose film was bonded on both sides of a polyvinyl alcohol film dyed and stretched with iodine to prepare an optical film with a pressure-sensitive adhesive. At this time, the gel fraction of the pressure-sensitive adhesive layer was 77% by weight, and the decomposition rate of the peroxide during drying was 88% by weight.

Example 3
(Preparation of optical film with adhesive)
Styrene oligomer (softening point: 72-77 ° C., weight average molecular weight: 1300, refractive index: 1.59, manufactured by Eastman Chemical Co., Pico, based on 100 parts by weight of the solid content of the modified acrylic polymer (b2) solution 30 parts by weight of Rustic A75), 0.35 parts by weight of dibenzoyl peroxide (1 minute half-life: 130 ° C.) as a cross-linking agent, and a polyisocyanate cross-linking agent (Mitsui Chemical Polyurethane) comprising a hexamethylene diisocyanate adduct of trimethylolpropane An acrylic pressure-sensitive adhesive solution (3) containing 0.08 part by weight of Takenate D160N (manufactured by Co., Ltd.) was prepared.

  Next, the acrylic pressure-sensitive adhesive solution (3) is applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm) and dried at 150 ° C. for 3 minutes. The pressure-sensitive adhesive layer having a thickness of 20 μm after drying was formed.

  The pressure-sensitive adhesive layer was transferred to a polarizing film in which a triacetylcellulose film was bonded on both sides of a polyvinyl alcohol film dyed and stretched with iodine to prepare an optical film with a pressure-sensitive adhesive. At this time, the gel fraction of the pressure-sensitive adhesive layer was 71% by weight, and the decomposition rate of peroxide during drying was 88% by weight.

Example 4
(Preparation of optical film with adhesive)
Copolymer of α-methylstyrene and styrene (softening point: 82-88 ° C., weight average molecular weight: 1200, refractive index: 1.61, relative to 100 parts by weight of the solid content of the modified acrylic polymer (b3) solution. Polyisocyanate comprising 25 parts by weight of Eastman Chemical Co., Ltd., Crystallex 3085), 0.3 parts by weight of dibenzoyl peroxide (1 minute half-life: 130 ° C.) as a crosslinking agent, and hexamethylene diisocyanate adduct of trimethylolpropane An acrylic pressure-sensitive adhesive solution (4) containing 0.1 part by weight of a cross-linking agent (manufactured by Mitsui Chemicals Polyurethanes, Takenate D160N) was prepared.

  Next, the acrylic pressure-sensitive adhesive solution (4) is applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm) and dried at 150 ° C. for 3 minutes. The pressure-sensitive adhesive layer having a thickness of 20 μm after drying was formed.

  The pressure-sensitive adhesive layer was transferred to a polarizing film in which a triacetylcellulose film was bonded on both sides of a polyvinyl alcohol film dyed and stretched with iodine to prepare an optical film with a pressure-sensitive adhesive. In addition, the gel fraction of the adhesive layer at this time was 84 weight%, and the decomposition rate of the peroxide at the time of drying was 88 weight%.

Example 5
(Preparation of optical film with adhesive)
A solution obtained by dissolving 0.2 parts by weight of dibenzoyl peroxide (1 minute half-life: 130 ° C.) in 10 parts by weight of toluene as a crosslinking agent with respect to 100 parts by weight of the solid content of the modified acrylic polymer (b4) solution, An acrylic pressure-sensitive adhesive solution (5) containing 0.2 part by weight of 3-glycidoxypropyltriethoxysilane as a silane coupling agent was prepared.

  Next, the acrylic pressure-sensitive adhesive solution (5) is applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm) and dried at 150 ° C. for 3 minutes. The pressure-sensitive adhesive layer having a thickness of 20 μm after drying was formed.

  The pressure-sensitive adhesive layer was transferred to a polarizing film in which a triacetylcellulose film was bonded on both sides of a polyvinyl alcohol film dyed and stretched with iodine to prepare an optical film with a pressure-sensitive adhesive. At this time, the gel fraction of the pressure-sensitive adhesive layer was 82% by weight, and the decomposition rate of peroxide during drying was 88% by weight.

Example 6
(Preparation of optical film with adhesive)
Addition of 0.3 part by weight of dibenzoyl peroxide (1 minute half-life: 130 ° C.) as a crosslinking agent and hexamethylene diisocyanate of trimethylolpropane to 100 parts by weight of the solid content of the modified acrylic polymer (b5) solution An acrylic pressure-sensitive adhesive solution (6) containing 0.06 part by weight of a polyisocyanate-based crosslinking agent (Mitsui Chemical Polyurethanes, Takenate D160N) was prepared.

  Next, the acrylic pressure-sensitive adhesive solution (6) is applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm) and dried at 150 ° C. for 3 minutes. The pressure-sensitive adhesive layer having a thickness of 20 μm after drying was formed.

  The pressure-sensitive adhesive layer was transferred to a polarizing film in which a triacetylcellulose film was bonded on both sides of a polyvinyl alcohol film dyed and stretched with iodine to prepare an optical film with a pressure-sensitive adhesive. At this time, the gel fraction of the pressure-sensitive adhesive layer was 75% by weight, and the decomposition rate of peroxide during drying was 88% by weight.

Example 7
(Preparation of optical film with adhesive)
With respect to 100 parts by weight of the solid content of the modified acrylic polymer (b5) solution, a styrene oligomer (softening point: room temperature or lower, weight average molecular weight: 440, refractive index: 1.60, manufactured by Eastman Chemical Co., Picolastic A5 ) 10 parts by weight, 0.3 parts by weight of dibenzoyl peroxide (1 minute half-life: 130 ° C.) as a cross-linking agent, and a polyisocyanate-based cross-linking agent made of hexamethylene diisocyanate adduct of trimethylolpropane (manufactured by Mitsui Chemicals Polyurethanes) An acrylic pressure-sensitive adhesive solution (7) containing 0.08 parts by weight of Takenate D160N) was prepared.

  Next, the acrylic pressure-sensitive adhesive solution (7) was applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm) and dried at 150 ° C. for 3 minutes. The pressure-sensitive adhesive layer having a thickness of 20 μm after drying was formed.

  The pressure-sensitive adhesive layer was transferred to a polarizing film in which a triacetylcellulose film was bonded on both sides of a polyvinyl alcohol film dyed and stretched with iodine to prepare an optical film with a pressure-sensitive adhesive. At this time, the gel fraction of the pressure-sensitive adhesive layer was 74% by weight, and the decomposition rate of the peroxide during drying was 88% by weight.

[Comparative Example 1]
(Preparation of optical film with adhesive)
0.3 parts by weight of dibenzoyl peroxide (1 minute half-life: 130 ° C.) as a crosslinking agent and hexamethylene diisocyanate adduct of trimethylolpropane with respect to 100 parts by weight of the solid content of the acrylic polymer (a1) solution An acrylic pressure-sensitive adhesive solution (8) containing 0.06 part by weight of a polyisocyanate-based crosslinking agent (Mitsui Chemicals Polyurethanes, Takenate D160N) was prepared.

  Next, the acrylic pressure-sensitive adhesive solution (8) was applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm) and dried at 150 ° C. for 3 minutes. The pressure-sensitive adhesive layer having a thickness of 20 μm after drying was formed.

  The pressure-sensitive adhesive layer was transferred to a polarizing film in which a triacetylcellulose film was bonded on both sides of a polyvinyl alcohol film dyed and stretched with iodine to prepare an optical film with a pressure-sensitive adhesive. At this time, the gel fraction of the pressure-sensitive adhesive layer was 75% by weight, and the decomposition rate of peroxide during drying was 88% by weight.

[Comparative Example 2]
(Preparation of optical film with adhesive)
Styrene oligomer (softening point: 72-77 ° C., weight average molecular weight: 1,300, refractive index: 1.59, manufactured by Eastman Chemical Co., picolastic, based on 100 parts by weight of the solid content of the acrylic polymer (a2) solution A75) 30 parts by weight, dibenzoyl peroxide (1 minute half-life: 130 ° C.) 0.35 parts by weight as a crosslinking agent, and a polyisocyanate-based crosslinking agent comprising a hexamethylene diisocyanate adduct of trimethylolpropane (Mitsui Chemical Polyurethane Co., Ltd.) An acrylic pressure-sensitive adhesive solution (9) containing 0.08 part by weight of Takenate D160N) was prepared.

  Next, the acrylic pressure-sensitive adhesive solution (9) 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. The pressure-sensitive adhesive layer having a thickness of 20 μm after drying was formed.

  The pressure-sensitive adhesive layer was transferred to a polarizing film in which a triacetylcellulose film was bonded on both sides of a polyvinyl alcohol film dyed and stretched with iodine to prepare an optical film with a pressure-sensitive adhesive. At this time, the gel fraction of the pressure-sensitive adhesive layer was 67% by weight, and the decomposition rate of peroxide during drying was 88% by weight.

  According to the above-mentioned method, the pressure-sensitive adhesive strength, durability, workability, refractive index, and haze value of the produced optical film with pressure-sensitive adhesive were measured and evaluated. The obtained results are shown in Table 1.

  From the results of Table 1 above, when the optical film with pressure-sensitive adhesive prepared according to the present invention is used (Examples 1 to 7), in any of the examples, the storage power test greatly increases the adhesive strength. It was found that the film was not peeled off and no adhesive residue was produced, and it was excellent in durability, workability, and removability.

  On the other hand, when the optical film with pressure-sensitive adhesive that does not satisfy the configuration of the present invention is used (Comparative Examples 1 and 2), in any of the comparative examples, suppression of increase in adhesive force due to the storage treatment and durability are arranged side by side. As a result, it became clear that it was inferior to the case where the pressure-sensitive adhesive layer of the present invention was used.

  As described above, the pressure-sensitive adhesive layer of the present invention exhibits excellent adhesive properties after the cross-linking treatment, does not cause defects such as foaming, floating and peeling in the heating test / humidification test, and has excellent durability and removability. It was found that the processing time was short, the refractive index was relatively high, and the loss of light due to reflection was small.

Claims (9)

On one side or both sides of the support, as a monomer unit, the general formula CH ₂ ═C (R ¹ ) COOR ² (where R ¹ is hydrogen or a methyl group, and R ² is an alkyl group having 2 to 14 carbon atoms). The glass transition temperature (Tg) of the homopolymer with respect to 100 parts by weight of the (meth) acrylic polymer (A) having a weight average molecular weight of 800,000 to 3 million and containing 50 to 98% by weight of the (meth) acrylic monomer represented. ) Modified (meth) acrylic polymer (B) obtained by polymerizing 10 to 100 parts by weight of a monomer having a higher glass transition temperature (Tg) than the (meth) acrylic polymer (A). the a PSA composition based polymer, relative to the 100 parts by weight of the base polymer, form a layer composed of an optical member for pressure-sensitive adhesive composition containing peroxide 0.02-2 parts by weight An optical member pressure-sensitive adhesive layer obtained by the method for producing an optical member pressure-sensitive adhesive layer comprising a step of performing a peroxide crosslinking treatment on the layer made of the pressure-sensitive adhesive composition for an optical member. Or the optical member with an adhesive characterized by forming in both surfaces . The optical member with pressure-sensitive adhesive according to claim 1, comprising 0.02 to 2 parts by weight of an isocyanate-based crosslinking agent with respect to 100 parts by weight of the base polymer. The optical member with an adhesive according to claim 1 or 2, comprising 0.01 to 1 part by weight of a silane coupling agent with respect to 100 parts by weight of the base polymer. The (meth) acrylic polymer (A) is a (meth) acrylic polymer containing 0.1 to 20% by weight of a hydroxyl group-containing monomer and 0.1 to 20% by weight of a carboxyl group-containing monomer as monomer units. The optical member with an adhesive according to any one of claims 1 to 3. The pressure-sensitive adhesive optical member according to claim 1, wherein the monomer is a (meth) acrylic monomer having an aromatic group. Furthermore, 10-100 weight part of tackifiers which have an aromatic ring or its hydrogenated material, and have a refractive index of 1.51-1.75 are contained with respect to 100 weight part of the base polymer. The optical member with an adhesive according to any one of the above items. The pressure-sensitive adhesive-equipped optical member according to claim 1, wherein the peroxide crosslinking treatment is a treatment for decomposing the peroxide by 50% by weight or more . The optical member with a pressure-sensitive adhesive according to any one of claims 1 to 7, wherein the pressure-sensitive adhesive layer for the optical member has a gel fraction of 40 to 90% by weight . An image display device using at least one optical member with an adhesive according to claim 8 .