JP2006348307A - Adhesive layer for optical member, optical member with adhesive, and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive layer or the like, hardly causing extreme increase of adhesive force or staining on an adherend even when an image display device is reused through sticking and peeling of an optical member, having excellent durability of hardly causing peeling or floating even after preservation at high temperature in high humidity, and also having excellent productivity of allowing stamping promptly after production of the optical member with the adhesive. <P>SOLUTION: The adhesive composition comprises 100 pts.wt. acrylic polymer containing ≥50 wt.% acrylic ester having a ≥4C alkyl group as a monomer unit, 0.02-2 pts.wt. peroxide and 0.01-1 pt.wt. silane coupling agent. The method for producing the adhesive composition, the adhesive layer formed by subjecting the adhesive composition to peroxide crosslinking treatment, the optical member with the adhesive wherein the adhesive layer is formed on one or both surfaces of the optical member, and the image display device using at least one of the optical member are also provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pressure-sensitive adhesive layer suitable for sticking or re-peeling an optical member. Furthermore, the present invention also relates to an optical member with an adhesive having the adhesive layer and an image display device such as a liquid crystal display device, an organic EL display device, and a PDP using the same.

  Optical members used in the liquid crystal display device, such as a polarizing plate and a retardation plate, are attached to the liquid crystal cell using an adhesive. Since the optical material used for such an optical member has a large expansion and contraction under a heating condition or a humidifying condition, it is likely to be lifted or peeled off after being attached. For this reason, the pressure-sensitive adhesive for optical members is required to have durability that can cope with the above-described conditions.

  In addition, when the optical member is attached to the liquid crystal cell, various processing processes such as punching and slitting are performed in a state where the adhesive is attached to the optical member. In such a case, the pressure-sensitive adhesive may be taken off by the cutting blade or may protrude from the cut surface, so that it is necessary to perform an aging treatment, which significantly impedes productivity. That is, it is very advantageous in terms of productivity that such processing can be quickly performed without aging after the optical member with an adhesive is manufactured.

  As an adhesive for attaching an optical member, an acrylic adhesive is generally used for advantages such as durability and transparency, and a crosslinking treatment is applied to give an appropriate cohesive force. It is normal. Various crosslinking agents are selected and used as the crosslinking method for such an acrylic pressure-sensitive adhesive, and a review of functional groups of the acrylic polymer and the crosslinking method has been published (see Non-Patent Document 1).

  Specific examples of the crosslinking agent for the adhesive for attaching an optical member include isocyanate compounds, epoxy compounds, aldehyde compounds, amine compounds, metal salts, metal alkoxides, ammonium salts, and hydrazine compounds (see Patent Document 1). ), Glycidyl compounds, isocyanate compounds, aziridine compounds, metal chelates and the like are also known (see Patent Document 2).

  On the other hand, Non-Patent Document 2 exemplifies organic peroxides as a crosslinking agent for rubber-based pressure-sensitive adhesives and silicone-based pressure-sensitive adhesives, but it is not described as a crosslinking agent for acrylic pressure-sensitive adhesives.

  As a peroxide cross-linking of an acrylic pressure-sensitive adhesive, a tape pressure-sensitive adhesive composition comprising a heat reaction product of an acrylic copolymer and an organic peroxide in the range of 1 to 6% by weight is known (Patent Document 3). See). Moreover, in patent document 4, the adhesive of less than 40 weight% of gel fraction which mix | blended 0.01-10 weight part of organic peroxide which a crosslinking reaction does not advance at 60-100 degreeC with an acrylic adhesive in a breathable base material. A method is disclosed in which an adhesive layer is transferred, the adhesive is softened by heating and impregnated into a base material, and then crosslinked to obtain a breathable adhesive. In Patent Document 5, an olefin polymer is cross-linked to an acrylic polymer obtained by copolymerizing a monomer having an olefin polymer in a side chain with an acrylate using an organic peroxide having a 10-hour half-life of 110 ° C. or less, thereby cross-linking the olefin part. Thus, a method for improving the cohesive force is disclosed.

  However, there is no known example in which the pressure-sensitive adhesive to be bonded to the optical member stabilizes characteristics by crosslinking with peroxide, has little change with time, and improves productivity.

Adhesive Handbook (2nd edition), edited by Adhesive Tape Industry Association, 1995.10.12. Page 147 Adhesive Handbook (2nd edition), edited by Adhesive Tape Industry Association, 1995.10.12. Pages 121 and 159 JP-A-8-199131 JP 2003-49141 A Japanese Patent Publication No. 35-4876 JP 2000-17237 A JP 2003-13027 A

  Adhesive layer obtained when isocyanate compounds, epoxy compounds, aldehyde compounds, amine compounds, metal salts, metal alkoxides, ammonium salts, hydrazine compounds, aziridine compounds, etc. that are generally used for crosslinking of optical adhesives are used After sticking to the optical member, the effects such as no foaming or peeling at high temperature and high humidity, excellent curved surface adhesion, no polarization loss, etc. are finally exhibited, but sufficient characteristics can be exhibited In many cases, aging is necessary to obtain a crosslinked state. The aging process prolongs the time until the optical member with an adhesive is punched and shipped, and thus the productivity is greatly reduced.

  In the present invention, even when the optical member is attached to the image display device, the optical member is peeled off and the image display device is reused. Providing a pressure-sensitive adhesive layer with excellent durability that does not peel off or float even when stored in an adhesive, and can be quickly punched after an optical member with pressure-sensitive adhesive is manufactured, and a method for manufacturing the same The purpose is to do. Moreover, an object of this invention is to provide the optical member which has the said adhesive layer, and an image display apparatus using the same.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have obtained a pressure-sensitive adhesive composition in which a specific peroxide and a silane coupling agent are blended with an acrylic polymer, and the above-mentioned problems are obtained by using such a composition. The inventors have found that this can be achieved and have completed the present invention.

  That is, the pressure-sensitive adhesive composition for an optical member of the present invention comprises 100 parts by weight of an acrylic polymer containing at least 50% by weight of an acrylic ester having an alkyl group having 4 or more carbon atoms as a monomer unit, a peroxide of 0.02 to It contains 2 parts by weight and 0.01 to 1 part by weight of a silane coupling agent.

  The pressure-sensitive adhesive composition for an optical member of the present invention comprises 100 parts by weight of an acrylic polymer containing at least 50% by weight of an acrylic ester having an alkyl group having 4 or more carbon atoms as a monomer unit, a peroxide of 0.02 to It contains 2 parts by weight, 0.01 to 1 part by weight of a silane coupling agent and 0.01 to 5 parts by weight of a crosslinking agent.

  In the optical member pressure-sensitive adhesive composition, the acrylic polymer preferably has a weight average molecular weight of 1,000,000 or more.

The method for producing the pressure-sensitive adhesive layer for an optical member of the present invention comprises:
0.02 to 2 parts by weight of peroxide and silane cup with respect to 100 parts by weight of an acrylic polymer containing at least 50% by weight of an acrylic ester having an alkyl group having 4 or more carbon atoms as a monomer unit and another acrylic ester A step of preparing 0.01 to 1 part by weight of a ring agent to prepare a pressure-sensitive adhesive composition, and a step of applying the pressure-sensitive adhesive composition onto a release-treated support, drying, and performing a peroxide crosslinking treatment Here, the gel fraction of the pressure-sensitive adhesive layer after the peroxide crosslinking treatment is 35 to 90% by weight,
It is characterized by including.

Moreover, the method for producing the pressure-sensitive adhesive layer for optical members of the present invention comprises:
0.02 to 2 parts by weight of a peroxide, 100 parts by weight of an acrylic polymer containing at least 50% by weight of an acrylic ester having 4 or more carbon atoms as a monomer unit and another acrylic ester, a silane cup A step of preparing a pressure-sensitive adhesive composition by mixing 0.01 to 1 part by weight of a ring agent and 0.01 to 5 parts by weight of a crosslinking agent, and applying the pressure-sensitive adhesive composition onto a release-treated support, followed by drying. The step of performing the peroxide crosslinking treatment, wherein the gel fraction of the pressure-sensitive adhesive layer after the peroxide crosslinking treatment is 35 to 90% by weight,
It is characterized by including.

  The pressure-sensitive adhesive layer of the present invention is formed by subjecting the pressure-sensitive adhesive composition for optical members to a peroxide crosslinking treatment.

  In the pressure-sensitive adhesive layer, the gel fraction is preferably 35 to 90% by weight.

  The optical member with pressure-sensitive adhesive of the present invention is characterized in that the pressure-sensitive adhesive layer is formed on one surface or both surfaces of the optical member.

  The image display device of the present invention is characterized by using at least one optical member with an adhesive.

  The pressure-sensitive adhesive composition of the present invention is prepared by blending an acrylic polymer with a peroxide and a silane coupling agent and, if necessary, a cross-linking agent, and coating, drying and cross-linking the pressure-sensitive adhesive composition. It is possible to form a pressure-sensitive adhesive layer that is set to have a rate. Even when the optical member on which the pressure-sensitive adhesive layer of the present invention is formed is attached to a liquid crystal cell and stored in a high temperature and high humidity state, high durability that does not cause peeling or foaming is exhibited. When the optical member attached to the liquid crystal cell via the pressure-sensitive adhesive layer of the present invention is peeled off again due to a sticking mistake or the like, it can be peeled without damaging or contaminating the liquid crystal cell. The pressure-sensitive adhesive layer of the present invention can provide an optical member with pressure-sensitive adhesive that is excellent in productivity that can quickly perform punching and slitting without requiring aging after the steps of coating, drying, and crosslinking.

  Moreover, the manufacturing method of the adhesive layer of this invention provides easily the adhesive layer set so that it might become a predetermined | prescribed gel fraction by performing a peroxide bridge | crosslinking process using the said adhesive composition. Can do.

  Furthermore, the image display device of the present invention is a liquid crystal display device, an organic EL display device, a PDP or the like using the optical member with an adhesive, and does not generate peeling or foaming even when stored in a high temperature and high humidity state. Even when the image display device is reused by peeling off the optical member due to durability, the adhesive force does not increase, and it has a function of easily peeling without adversely affecting the device.

  The pressure-sensitive adhesive composition for optical members of the present invention is mainly composed of an acrylic polymer containing at least 50% by weight of an acrylic ester having an alkyl group having 4 or more carbon atoms as a monomer unit. It is preferable that the acrylic polymer further contains an unsaturated carboxylic acid.

  Here, examples of the acrylic ester having an alkyl group having 4 or more carbon atoms include butyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, isoamyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, isononyl acrylate, and isomyristyl acrylate. Are specifically mentioned, and may be used alone or in combination of two or more.

  The acrylic polymer contains at least 50% by weight, preferably 60 to 99% by weight, of an acrylic ester having an alkyl group having 4 or more carbon atoms. However, if the amount is too small, the stress relaxation property is poor, which is not preferable.

  Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, itaconic acid, maleic acid and the like, and acrylic acid and methacrylic acid are particularly preferably used.

  The acrylic polymer preferably contains 0.2 to 10% by weight, more preferably 1.0 to 7.0% by weight of an unsaturated carboxylic acid. If it is too large and too small, the durability is adversely affected, which is not preferable.

  The acrylic polymer can contain other monomers as long as it contains the acrylic ester having an alkyl group having 4 or more carbon atoms and an unsaturated carboxylic acid in the above proportion as monomer units. Other monomers include monomers having no functional group such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) Examples include monomers having a hydroxyl group such as acrylate, acrylamide, dimethylaminomethylacrylamide, acryloylmorpholine, glycidyl acrylate, and the like. These monomers can be used alone or in combination of two or more.

  The other monomer preferably has a functional group having reactivity with a crosslinking agent. When the acrylic polymer contains such a monomer, its content is 0.02 to 1% by weight, preferably 0.04 to 0.4% by weight.

  The weight average molecular weight of the polymer having such a composition is preferably 1,000,000 or more, more preferably 1,200,000 to 3,000,000. When the weight average molecular weight is less than 1,000,000, durability is poor, and when it is too large, workability tends to be lowered.

The weight average molecular weight is a value measured by GPC. The weight average molecular weight measured by GPC is a value determined in terms of polystyrene. GPC measurement conditions were as follows: GPC apparatus: HLC-8120 GPC manufactured by Tosoh Corporation, column: G7000H _XL + GMH _XL + GMH _XL manufactured by Tosoh Corporation, solvent: tetrahydrofuran, temperature 40 ° C., flow rate 0.8 ml / min, detector: differential refractometer is there.

  For the production of such an acrylic polymer, a known radical polymerization method such as solution polymerization, bulk polymerization or emulsion polymerization can be appropriately selected. As the radical polymerization initiator, various known azo and peroxide initiators can be used.

  In solution polymerization, 0.01 to 0.2 parts by weight of a polymerization initiator such as azobisisobutyronitrile is used, and a reaction is performed at 50 to 70 ° C. for 8 to 30 hours under a nitrogen stream using a polymerization solvent. Can be obtained. As the polymerization solvent, for example, an organic solvent such as ethyl acetate or toluene is used. The solution concentration is usually about 20 to 80% by weight. In addition, from the recent environmentally-friendly movement, a method that does not use an organic solvent such as a suspension polymerization method or an emulsion polymerization method is preferably used.

  The emulsion polymerization may be performed by, for example, combining a monomer component containing an acrylate ester as a main component together with a polymerization initiator, an emulsifier, and a chain transfer agent, if necessary, in water. For example, a known emulsion polymerization method such as a batch polymerization method, a continuous dropping polymerization method, or a divided dropping polymerization method can be employed. In addition, although reaction conditions etc. are selected suitably, superposition | polymerization temperature is about 20-100 degreeC, for example.

  The polymerization initiator is not particularly limited, and a known radical polymerization initiator usually used for emulsion polymerization is used. For example, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylpropionamidine) disulfate, 2,2′-azobis (2-amidinopropane) dihydrolide, 2,2 Azo initiators such as' -azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis (N, N'-dimethyleneisobutylamidine), such as Persulfate initiators such as potassium persulfate and ammonium persulfate, for example, peroxide initiators such as benzoyl peroxide, t-butyl hydroperoxide, hydrogen peroxide, such as persulfate and sodium bisulfite And redox initiators such as a combination of peroxide and sodium ascorbate.

  These polymerization initiators are suitably used alone or in combination. Moreover, the compounding quantity of a polymerization initiator is about 0.005-1 weight part with respect to 100 weight part of monomer components, for example.

  The emulsifier is not particularly limited, and known emulsifiers commonly used in emulsion polymerization are used. For example, sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulphonate, polyoxyethylene sodium lauryl sulfate, polyoxyethylene alkyl Anionic emulsifiers such as sodium ether sulfate, sodium polyoxyethylene lauryl sulfate, sodium polyoxyethylene alkyl ether sulfate, ammonium polyoxyethylene alkyl phenyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, sodium polyoxyethylene alkyl sulfosuccinate, for example , Polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester Ether, nonionic emulsifier such as polyoxyethylene polyoxypropylene block polymers, other, for example, such as a radical polymerizable emulsifier introduced and propenyl group.

  These emulsifiers are used alone or in combination as appropriate. Moreover, the compounding quantity of an emulsifier is 0.2-10 weight part with respect to 100 weight part of monomer components, Preferably, it is about 0.5-5 weight part.

  The chain transfer agent adjusts the molecular weight of the copolymer as necessary, and a chain transfer agent usually used for emulsion polymerization is used. For example, 1-dodecanethiol, mercaptoacetic acid, 2-mercaptoethanol, And mercaptans such as 2-ethylhexyl thioglycolate and 2,3-dimethylcapto-1-propanol.

  These chain transfer agents are appropriately used alone or in combination. Moreover, the compounding quantity of a chain transfer agent is about 0.001-0.5 weight part with respect to 100 weight part of monomer components, for example.

  By such emulsion polymerization, an acrylic water-dispersed polymer containing an emulsifier and an acrylic polymer dispersed in water, that is, an adhesive component containing the emulsifier can be obtained.

  The acrylic water-dispersed polymer containing an emulsifier is obtained, for example, by polymerizing a monomer component mainly composed of an acrylate ester by a method other than emulsion polymerization and then dispersing it in water using the above-described emulsifier. You can also

  The obtained acrylic polymer is in a solution state, a water dispersion state, a solid state that can flow by heating, and the like.

  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 for the polymerization reaction. If necessary, it is added again to obtain a predetermined amount of peroxide.

  Any peroxide can be used as long as it can generate radicals by heating to achieve crosslinking of the pressure-sensitive adhesive polymer. However, in consideration of workability and stability, the 1-minute half-life temperature is 80 ° C. to A peroxide of 160 ° C., preferably 90 ° C. to 140 ° C. is used. If the half-life temperature for 1 minute is too low, a reaction may occur during storage before coating and drying, resulting in a viscosity increase that makes the coating impossible. On the other hand, if the temperature is too high, the temperature during the cross-linking reaction will increase, causing side reactions or peroxidation. The product may remain and cross-linking with time may proceed, which is not preferable.

  Examples of such peroxides include di (2-ethylhexyl) peroxydicarbonate (1 minute half-life temperature 90.6 ° C), di (4-t-butylcyclohexyl) peroxydicarbonate (92.1 ° C). ), Di-sec-butyl peroxydicarbonate (92.4 ° C.), t-butyl peroxyneodecanoate (103.5 ° C.), t-hexyl peroxypivalate, (109.1 ° C.) ), T-butyl peroxypivalate (110.3 ° C.), dilauroyl peroxide (116.4 ° C.), di-n-octanoyl peroxide (117.4 ° C.), 1,1,3 , 3-tetramethylbutylperoxy-2-ethylhexanoate (124.3 ° C.), di (4-methylbenzoyl) peroxide (128.2 ° C.), dibenzoyl peroxide Sid (130.0 ° C.), t-butyl peroxybutyrate (136.1 ° C.) and the like, and di (4-t-butylcyclohexyl) peroxydicarbonate and dilauroyl having particularly excellent crosslinking reaction efficiency Peroxide and dibenzoyl peroxide are preferably used.

  Such a peroxide is used in an amount of 0.02 to 2 parts by weight, preferably 0.05 to 1 part by weight based on 100 parts by weight of the acrylic polymer. If the amount is too small, the crosslinking reaction becomes insufficient and the durability is inferior. If the amount is too high, crosslinking is excessive and the adhesiveness is poor.

  Peroxide half-life is an index that represents the decomposition rate of peroxide, is the time when the amount of peroxide decomposition is halved, the decomposition temperature to obtain a half-life at any time, The half-life time at an arbitrary temperature is described in the manufacturer catalog and the like, for example, in the organic peroxide catalog 9th edition (May 2003) published by Nippon Oil & Fats Co., Ltd.

  Examples of silane coupling agents include epoxy group-containing silane couplings such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane. Agents, amino such as 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminoprolylmethyldimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine Group-containing silane coupling agents, (meth) acrylic group-containing silane coupling agents such as 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, and isocyanate group-containing silanes such as 3-isocyanatopropyltriethoxysilane Couple Such as grayed agents.

  The silane coupling agent is blended in an amount of 0.01 to 1 part by weight, preferably 0.02 to 0.6 part by weight, based on 100 parts by weight of the acrylic polymer. When the blending amount increases, the adhesion to an image display device such as a liquid crystal cell may increase and the removability may be poor. When the blending amount decreases, the durability may decrease.

  The pressure-sensitive adhesive composition for an optical member obtained by blending an acrylic polymer with a peroxide and a silane coupling agent is coated on a support, dried, and the gel fraction of the pressure-sensitive adhesive after crosslinking is 35 to 90% by weight. The peroxide crosslinking treatment is preferably performed so as to be 40 to 85% by weight. When the gel fraction is too small, the processability is inferior, and when it is too large, the adhesiveness tends to be inferior. In order to obtain a gel fraction in such a range, it is natural to adjust the amount of peroxide, but the crosslinking treatment temperature and time are also important, and the amount of decomposition of the peroxide is 50% or more, The setting of the crosslinking treatment temperature and time so as to be preferably 75% or more is a standard. If the decomposition amount of the peroxide is small, the remaining peroxide is increased and a cross-linking reaction over time occurs, which is not preferable.

  Specifically, for example, when the crosslinking treatment temperature is 1 minute half-life temperature, the decomposition amount is 50% in 1 minute and 75% in 2 minutes, and it is necessary to heat treatment for 1 minute or more. If the peroxide half-life time is 30 seconds, a crosslinking treatment of 30 seconds or more is required. If the peroxide half-life time at the crosslinking treatment temperature is 5 minutes, a crosslinking treatment of 5 minutes or more is required. It becomes.

  In this way, the crosslinking treatment temperature and time are proportionally calculated and adjusted from the half-life time assuming that the peroxide is temporarily proportional, depending on the peroxide used. It is necessary to heat-treat. Of course, the temperature at the time of drying may be used as it is, or it may be processed after drying. The processing time is set in consideration of productivity and workability, but 0.2 to 20 minutes, preferably 0.5 to 10 minutes is used.

  The pressure-sensitive adhesive composition for an optical member of the present invention can be used in combination with a commonly used crosslinking agent (excluding peroxide) for adjusting the pressure-sensitive adhesive properties. At this time, the gel fraction after the crosslinking treatment by heating is 35 to 90% by weight, preferably 40 to 70% by weight, and the gel fraction after the treatment such as aging is 40 to 90% by weight, preferably It is used so that it may become 45 to 85 weight%. If the gel fraction is too large, the adhesiveness is inferior, and if it is too small, the processability is inferior.

  The crosslinking agent (excluding peroxide) is a polyfunctional compound that can react with a polymer to form a crosslinked structure, such as tolylene diisocyanate, diphenylmethane diisocyanate, diisocyanate adducts to various polyols, and epoxy compounds. , Aziridine compounds, melamine compounds, metal salts, metal chelate compounds and the like, and polyisocyanate compounds are preferably used. In particular, a hydroxyl group-containing monomer such as 2-hydroxyethyl acrylate is copolymerized during the production of the polymer to introduce a hydroxyl group into the polymer, and a polyisocyanate compound is used as a crosslinking agent. The amount of such a crosslinking agent varies depending on the material used, but is usually in the range of 0.01 to 5 parts by weight with respect to 100 parts by weight of the acrylic polymer.

  The pressure-sensitive adhesive composition obtained as described above can be blended with an ultraviolet absorber, an anti-aging agent, a softening agent, a dye, a pigment, a filler and the like, if necessary. Moreover, you may employ | adopt the redox type | system | group which adds a reducing agent in the range which can be controlled.

  The manufacturing method of the adhesive layer for optical members of this invention includes the process of apply | coating on the support body which carried out the peeling process of the said adhesive composition, drying, and carrying out a peroxide bridge | crosslinking process. This step is as described above.

  The pressure-sensitive adhesive layer formed by the production method is transferred to an optical member, or the pressure-sensitive adhesive composition is directly applied to the optical member, dried, and subjected to crosslinking treatment to obtain an optical member. That is, the optical member of the present invention is formed by forming an adhesive layer on one or both sides of the optical member. Such a coating method may be any coating method such as a roll coater such as a reverse coater or a gravure coater, a curtain coater, a lip coater or a die coater, and the pressure-sensitive adhesive thickness after drying is usually 2 to 500 μm, preferably 5 Processed at ˜100 μm. When the adhesive layer is exposed on the surface, it is protected with a peeled sheet until it is put to practical use.

  The optical member with pressure-sensitive adhesive of the present invention has a pressure-sensitive adhesive layer crosslinked with a peroxide, so that punching and slitting can be performed quickly without requiring aging after the steps of coating, drying and crosslinking. Demonstrates excellent productivity. The reason for this is not clear, but I think as follows. This peroxide crosslinking takes the form of crosslinking in which radicals are generated in the polymer main chain by the hydrogen abstraction reaction of the polymer main chain due to radicals generated from the peroxide and crosslink, and the entire polymer main chain is incorporated into the crosslinked structure. Because the entire adhesive is cross-linked uniformly, even if processing such as punching is performed immediately after the cross-linking treatment, the adhesive will adhere to the cutting blade, and the post-processing glue will not stick out. It is presumed that the characteristics can be stabilized because the crosslinking reaction with time does not occur by performing the predetermined crosslinking treatment.

  An optical member used for forming a liquid crystal display device or the like is used, and the type thereof is not particularly limited. For example, the optical member includes a polarizing plate. A polarizing plate having a transparent protective film on one or both sides of a polarizer is generally used.

  The polarizer is not particularly limited, and various types can be used. As a polarizer. For example, dichroic substances such as iodine and dichroic dyes are adsorbed on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films. And a polyene-based oriented film such as a uniaxially stretched product, a dehydrated polyvinyl alcohol product or a dehydrochlorinated polyvinyl chloride product. 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 a thermoplastic resin having unsubstituted phenyl and 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 + ny) / 2−nz] · d (where nx and ny are the main refractive index in the plane of the film, nz is the refractive index in the film thickness direction, and d is the film thickness). A protective film having a retardation value in the film thickness direction 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.

  The hard coat treatment is applied for the purpose of preventing scratches on the surface of the polarizing plate. For example, a transparent protective film with a cured film excellent in hardness, sliding properties, etc. by an appropriate ultraviolet curable resin such as acrylic or silicone is used. It can be formed by a method of adding to the surface of the film. The antireflection treatment is performed for the purpose of preventing the 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 prior art. Further, the anti-sticking treatment is performed for the purpose of preventing adhesion with an adjacent layer.

  The anti-glare treatment is applied for the purpose of preventing the outside light from being reflected on the surface of the polarizing plate and obstructing the visibility of the light transmitted through the polarizing plate. For example, the surface is roughened by a sandblasting method or an embossing method. It can be formed by imparting a fine concavo-convex structure to the surface of the transparent protective film by an appropriate method such as a blending method of transparent particles. The fine particles to be included in the formation of the surface fine concavo-convex structure are, for example, conductive materials made of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide or the like having an average particle diameter of 0.5 to 50 μm. In some cases, transparent fine particles such as inorganic fine particles, organic fine particles made of a crosslinked or uncrosslinked polymer, and the like are used. When forming a surface fine uneven structure, the amount of fine particles used is generally about 2 to 50 parts by weight, preferably 5 to 25 parts by weight, based on 100 parts by weight of the transparent resin forming the surface fine uneven structure. The antiglare layer may also serve as a diffusion layer (viewing angle expanding function or the like) for diffusing the light transmitted through the polarizing plate to expand the viewing angle.

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

  Examples of the optical member of the present invention include a liquid crystal display device such as a reflection plate, a semi-transmission plate, a phase difference 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 formation is mention | raise | lifted. 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 a semi-transmissive polarizing plate in which a polarizing plate is further laminated with a reflecting plate or a semi-transmissive reflecting plate, an elliptical polarizing plate or a circular polarizing plate in which a retardation plate is further laminated on a polarizing plate, a polarizing plate A wide viewing angle polarizing plate in which a 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). Such a light source can be omitted, and the liquid crystal display device can be easily thinned. The reflective polarizing plate can be formed by an appropriate method such as a method in which a reflective layer made of metal or the like is attached to one surface of the polarizing plate via a transparent protective layer or the like as necessary.

  Specific examples of the reflective polarizing plate include those in which a reflective layer is formed by attaching a foil or a vapor deposition film made of a reflective metal such as aluminum on one side of a transparent protective film matted as necessary. 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. 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 is formed by transparent the 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 protective layer.

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

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

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

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

  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 copolymers, grafts thereof A copolymer, a friend thing, etc. are mention | raise | lifted. 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 the main chain type liquid crystalline polymer include, for example, a nematic alignment polyester liquid crystalline polymer, a discotic polymer, and a cholesteric polymer having a structure in which a mesogen group is bonded to a spacer portion that imparts flexibility. . 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 property 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 para-substituted cyclic compound unit. These liquid crystalline polymers are prepared by, for example, applying a solution of a liquid crystalline polymer on an alignment surface such as those obtained by rubbing the surface of a thin film such as polyimide or polyvinyl alcohol formed on a glass plate, or 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 those for the purpose of compensating for various wavelength plates or birefringence of the liquid crystal layer, viewing angle, and the like. What laminated | stacked the phase difference plate and controlled optical characteristics, such as phase difference, etc. may be used.

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

  The 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. As such a viewing angle compensation phase difference plate, for example, a phase difference plate, an alignment film such as a liquid crystal polymer, or an alignment layer such as a liquid crystal polymer supported on a transparent substrate is used. 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 inclined alignment film include a film obtained by bonding a heat shrink film to a polymer film and stretching or / and shrinking the polymer film under the action of the contraction force by heating, and a film obtained by obliquely aligning a liquid crystal polymer. Can be mentioned. The raw material polymer for the phase difference plate is the same as the polymer described in the previous phase difference plate, preventing coloration due to a change in the viewing angle based on the phase difference by the liquid crystal cell and expanding the viewing angle for good visual recognition. An appropriate one for the purpose can be used.

  Also, from the viewpoint of achieving a wide viewing angle with good visibility, an optically compensated phase difference in which a liquid crystal polymer alignment layer, in particular an optically anisotropic layer composed of a discotic liquid crystal polymer gradient alignment layer, is supported by a triacetylcellulose film. A plate can be preferably used.

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

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

  Therefore, in the brightness enhancement film of the type that transmits linearly polarized light having the predetermined polarization axis as described above, the transmitted light is incident on the polarizing plate with the polarization axis aligned as it is, thereby efficiently transmitting while suppressing absorption loss due to the polarizing plate. Can be made. On the other hand, in a brightness enhancement film of a type that emits circularly polarized light such as a cholesteric liquid crystal layer, it can be incident on a polarizer as it is, but from the viewpoint of suppressing absorption loss, the circularly polarized light is linearly polarized through a retardation plate. 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 exhibits, for example, a retardation layer that functions as a quarter-wave plate for light-color light having a wavelength of 550 nm and other retardation characteristics. A phase difference layer, for example, a phase difference layer that functions as a half-wave plate, can be used to superimpose. 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, the cholesteric liquid crystal layer can also be obtained by reflecting circularly polarized light in a wide wavelength range such as the visible light region by combining two or more layers with different reflection wavelengths and having an overlapping structure. Based on this, transmitted circularly polarized light in a wide wavelength range can be obtained.

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

  The optical member in which the optical layer is laminated on the polarizing plate can be formed by a method of sequentially laminating separately in the manufacturing process of a liquid crystal display device or the like. There is an advantage that the manufacturing process of a liquid crystal display device or the like can be improved because of excellent stability and assembly work. For the lamination, an appropriate adhesive means such as an adhesive layer can be used. When adhering the polarizing plate and the other optical layer, their optical axes can be set at an appropriate arrangement angle in accordance with the target 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. What gave the ultraviolet absorptivity by systems, such as a system processed with a ultraviolet absorber, etc. may be used.

  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 particular limitation except that an optical member is used. As the liquid crystal cell, any 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 the liquid crystal display device, for example, a single layer or a suitable layer such as a diffusing plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusing plate, a backlight, etc. Two or more layers can be arranged.

  Next, an organic electroluminescence device (organic EL display device) will be described. Generally, in an organic EL display device, a transparent electrode, an organic light emitting layer, and a metal electrode are sequentially laminated on a transparent substrate to form a light emitter (organic electroluminescent light emitter). Here, the organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative and the like and a light emitting layer made of a fluorescent organic solid such as anthracene, Or, a structure having various combinations such as a laminate of such a light emitting layer and an electron injection layer made of a perylene derivative or the like, or a laminate 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 light is emitted when the excited fluorescent material returns to the ground state. The mechanism of recombination in the middle is the same as that of a general diode, and as can be predicted from this, the current and the emission intensity show strong nonlinearity with rectification with respect to the applied voltage.

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

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

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

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

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

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

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

Example 1
70 parts of isononyl acrylate, 25 parts of butyl acrylate, 5 parts of acrylic acid, 0.1 part of 2,2-azobisisobutyronitrile and 200 parts of ethyl acetate, 4 necks equipped with nitrogen introduction pipe and cooling pipe The flask was put into a flask and sufficiently purged with nitrogen, and then a polymerization reaction was carried out at 55 ° C. for 20 hours with stirring under a nitrogen stream to obtain an acrylic polymer having a weight average molecular weight of 1.25 million.

  A pressure-sensitive adhesive in which 0.4 part of dibenzoyl peroxide (1 minute half-life 130.0 ° C.) and 0.1 part of 3-glycidoxypropyltrimethoxysilane are mixed with 100 parts of the solid content of the polymer solution. The composition was applied to 38 μm PET subjected to silicone release treatment so that the dry thickness of the pressure-sensitive adhesive layer was 25 μm, dried at 130 ° C. for 3 minutes and crosslinked (the calculated decomposition amount of the peroxide was about 88%) and transferred to a polarizing film to obtain an optical member with an adhesive of the present invention. The gel fraction of the pressure-sensitive adhesive was 71% by weight. In addition, even if this adhesive was stored at 60 ° C. for 1 month, no increase in gel fraction was observed.

(Example 2)
The pressure-sensitive adhesive composition of Example 1 was dried and crosslinked at 140 ° C. for 3 minutes (the calculated amount of peroxide decomposition was about 99%), transferred to a polarizing film, and the pressure-sensitive adhesive optical member of the present invention. It was. The gel fraction of the pressure-sensitive adhesive was 71% by weight.

(Example 3)
The pressure-sensitive adhesive composition of Example 1 was dried and crosslinked at 120 ° C. for 9 minutes (the calculated amount of peroxide decomposition was about 90%), transferred to a polarizing film, and the pressure-sensitive adhesive optical member of the present invention. It was. The gel fraction of the pressure-sensitive adhesive was 70% by weight.

(Reference Example 1)
The pressure-sensitive adhesive composition of Example 1 was dried and crosslinked at 110 ° C. for 3 minutes (the calculated decomposition amount of peroxide was about 19%), transferred to a polarizing film, and the optical member with pressure-sensitive adhesive of Reference Example. It was. The gel fraction of the pressure-sensitive adhesive was 5% by weight.

(Comparative Example 1)
In Example 1, an optical member with a pressure-sensitive adhesive of Comparative Example was obtained in the same manner as Example 1 except that 0.01 part of dibenzoyl peroxide was used. The gel fraction of the pressure-sensitive adhesive was 0% by weight.

(Comparative Example 2)
In Example 1, an optical member with a pressure-sensitive adhesive of Comparative Example was obtained in the same manner as Example 1 except that 3 parts of dibenzoyl peroxide was used. The gel fraction of the pressure-sensitive adhesive was 95% by weight.

(Comparative Example 3)
In Example 1, the same procedure as in Example 1 was conducted except that 3 parts of dibenzoyl peroxide was used and drying and crosslinking were carried out at 110 ° C. for 3 minutes (the decomposition amount of the peroxide obtained by calculation was about 19%). Thus, an optical member with a pressure-sensitive adhesive of Comparative Example was obtained. The gel fraction of the pressure-sensitive adhesive was 82% by weight.

(Comparative Example 4)
In Example 1, an optical member with a pressure-sensitive adhesive of Comparative Example was obtained in the same manner as in Example 1 except that 0.005 part of 3-glycidoxypropyltrimethoxysilane was used. The gel fraction of the pressure-sensitive adhesive was 71% by weight.

(Comparative Example 5)
In Example 1, an optical member with a pressure-sensitive adhesive of Comparative Example was obtained in the same manner as Example 1 except that 2-glycidoxypropyltrimethoxysilane was changed to 2 parts. The gel fraction of the pressure-sensitive adhesive was 71% by weight.

Example 4
70 parts of 2-ethylhexyl acrylate, 29 parts of butyl acrylate, 1.0 part of acrylic acid, 0.05 part of 2,2-azobisisobutyronitrile and 200 parts of ethyl acetate were provided with a nitrogen introduction tube and a cooling tube. After putting into a four-necked flask and sufficiently purging with nitrogen, a polymerization reaction was carried out at 55 ° C. for 20 hours while stirring under a nitrogen stream to obtain an acrylic polymer having a weight average molecular weight of 1,460,000.

  0.2 parts of di (4-t-butylcyclohexyl) peroxydicarbonate (1 minute half-life 92.1 ° C.), 3-glycidoxypropyltriethoxysilane The pressure-sensitive adhesive composition containing 2 parts was applied to 38 μm PET subjected to silicone release treatment so that the dry thickness of the pressure-sensitive adhesive layer was 25 μm, dried at 130 ° C. for 3 minutes, and crosslinked (calculated The decomposition amount of the oxide was approximately 100%), transferred to a polarizing film, and used as an optical member with an adhesive of the present invention. The gel fraction of the pressure-sensitive adhesive was 82% by weight.

(Example 5)
95 parts of butyl acrylate, 5 parts of acrylic acid, 0.1 part of 2-hydroxyethyl acrylate, 0.05 part of 2,2-azobisisobutyronitrile and 200 parts of ethyl acetate, equipped with nitrogen introduction pipe and cooling pipe The mixture was placed in a four-necked flask and sufficiently purged with nitrogen, and then a polymerization reaction was carried out at 55 ° C. for 20 hours with stirring under a nitrogen stream to obtain an acrylic polymer having a weight average molecular weight of 1,570,000.

  A pressure-sensitive adhesive composition in which 0.2 part of dibenzoyl peroxide (1 minute half-life 130.0 ° C.) and 0.08 part of 3-glycidoxypropyltrimethoxysilane are blended with 100 parts of the solid content of the polymer solution. Was applied to 38 μm PET subjected to silicone release treatment so that the dry thickness of the pressure-sensitive adhesive layer was 25 μm, dried at 140 ° C. for 3 minutes, and crosslinked (the decomposition amount of peroxide obtained by calculation was about 99%). ) And transferred to a polarizing film to obtain an optical member with an adhesive of the present invention. The gel fraction of the pressure-sensitive adhesive was 75% by weight.

(Example 6)
0.1 part of dibenzoyl peroxide (1 minute half-life 130.0 ° C.), 0.08 part of 3-glycidoxypropyltrimethoxysilane, and further crosslinking with respect to 100 parts of the solid content of the polymer solution of Example 5 A pressure-sensitive adhesive layer having a dry thickness of a pressure-sensitive adhesive layer obtained by subjecting a pressure-sensitive adhesive composition obtained by uniformly mixing 0.5 part of a polyisocyanate-based cross-linking agent composed of a tolylene diisocyanate adduct of trimethylolpropane as an agent to a silicone-peeled 38 μm PET. Apply to 25 μm, dry at 130 ° C. for 3 minutes and cross-link (calculated peroxide decomposition amount is about 88%), transfer to polarizing film, did. The gel fraction of the pressure-sensitive adhesive was 68% by weight.

(Comparative Example 6)
In Example 6, an optical member with a pressure-sensitive adhesive of Comparative Example was obtained in the same manner as in Example 6 except that 0.8 part of a polyisocyanate-based crosslinking agent was used without using dibenzoyl peroxide. The gel fraction of the pressure-sensitive adhesive was 6% by weight. The gel fraction became 68% by weight after aging at 30 ° C. for 1 week, but the evaluation was performed before aging.

(Example 7)
At the time of polymer polymerization in Example 5, the polymerization was performed using 0.2 part of dibenzoyl peroxide instead of 0.05 part of 2,2-azobisisobutyronitrile to obtain a polymer having a weight average molecular weight of 1.3 million. . Further, when the residual peroxide was quantified by liquid chromatography, 0.06 part remained.

  To 100 parts of the solid content of the polymer solution, 0.14 part of dibenzoyl peroxide was added, and the same operation as in Example 5 was performed to obtain an optical member with a pressure-sensitive adhesive of the present invention. The gel fraction of the pressure-sensitive adhesive was 72% by weight.

(Example 8)
A monomer mixture of 70 parts of butyl acrylate, 27 parts of 2-ethylhexyl acrylate, 2 parts of acrylic acid, and 1 part of 6-hydroxyhexyl acrylate was used as an emulsifier, and 3 parts of polyoxyethylene distyrenated phenyl ether ammonium sulfate water 122 Emulsified in a portion, 0.05 part of 2,2-azobis (2-amidinopropane) dihydrochloride as an initiator is used, and a polymerization reaction is performed at 50 ° C. for 3 hours, and further reacted at 65 ° C. for 2 hours. The viscosity was adjusted with ammonia water to obtain an aqueous dispersion of an acrylic polymer.

  To 100 parts of the solid content of the acrylic polymer aqueous dispersion, 0.2 parts of dibenzoyl peroxide (1 minute half-life 130.0 ° C.) and 0.1 part of 3-glycidoxypropyltriethoxysilane are added to ethyl acetate. The pressure-sensitive adhesive composition, which was dissolved in 5 parts and uniformly stirred, was applied to 38 μm PET that had been subjected to silicone release treatment so that the dry thickness of the pressure-sensitive adhesive layer was 25 μm and dried at 130 ° C. for 3 minutes. And the crosslinking (the decomposition amount of the peroxide obtained by calculation is about 88%) was performed, transferred to a polarizing film, and used as an optical member with an adhesive of the present invention. The gel fraction of the pressure-sensitive adhesive was 78% by weight.

Example 9
Polyurethane dispersion (Takelac W-511, manufactured by Mitsui Takeda Chemical Co., Ltd.) 50 parts (solid content 40.0% by weight), water 200 parts, butyl acrylate 77 parts, 6-hydroxyhexyl acrylate 3 parts The body mixture was added and absorbed into the urethane water dispersion. Urethane which does not use an emulsifier by adding 0.08 part of 2,2-azobis (N- (2-carboxyethyl) -2-methyl-propionamidine and heating to 55 ° C. under nitrogen flow for 5 hours. -An acrylic polymer aqueous dispersion was obtained.

  In the same manner as in Example 8, a peroxide and a silane coupling agent were blended, applied, dried, and crosslinked to obtain an optical member with a pressure-sensitive adhesive of the present invention. The gel fraction of the pressure-sensitive adhesive was 81% by weight.

(Measurement of gel fraction)
The dried and crosslinked pressure-sensitive adhesive (initial weight W1) was immersed in an ethyl acetate solution and allowed to stand at room temperature for 1 week, then the insoluble matter was taken out, and the dried weight (W2) was measured.
Gel fraction (% by weight) = (W2 / W1) × 100
I asked for it.

(Adhesive strength)
The optical member having a width of 25 mm obtained in Examples and Comparative Examples was pasted on a non-alkali glass plate by one reciprocation of a 2 kg roll, treated for 30 minutes in an autoclave at 50 ° C. and 0.5 MPa, and then subjected to conditions at 23 ° C. and 50%. Then, the peel adhesion was measured at a peel angle of 90 ° and a peel speed of 300 mm / min. In addition, after autoclaving, it was stored at 70 ° C. for 6 hours, allowed to stand at 23 ° C. and 50% for 3 hours, then measured for peel adhesion at a peel angle of 90 ° and a peel speed of 300 mm / min. Power.

(durability)
The 12-inch sized optical member obtained in Examples and Comparative Examples was attached to an alkali-free glass having a thickness of 0.5 mm, treated for 30 minutes in an autoclave at 50 ° C. and 0.5 MPa, and then at 60 ° C. and 90% RH. It was put into the atmosphere for 500 hours, and if there was no peeling or floating of the optical member, it was rated as ◯, and if it was, it was marked as x.

(Processability)
The optical members with pressure-sensitive adhesives of Examples and Comparative Examples were punched using a press machine without performing an aging treatment. At that time, the case where the adhesive was not removed by the cutting blade was marked as ◯, and the case where the adhesive was removed or adhered was marked as x.

  From Table 1, the optical member with pressure-sensitive adhesive of the present invention exhibits high durability that does not cause peeling or foaming even after being attached and stored in a high temperature and high humidity state. Even when used, the adherend is not contaminated, and after passing through the steps of coating, drying and cross-linking, it does not require aging and has excellent punching workability. . On the other hand, it can be seen that the optical member of the comparative example is not obtained that satisfies all the characteristics.

Claims (5)

  100 parts by weight of an acrylic polymer containing at least 50% by weight of an acrylic ester having an alkyl group having 4 or more carbon atoms as a monomer unit, 0.02 to 2 parts by weight of a peroxide, and 0.01 to 1 weight of a silane coupling agent An adhesive layer formed by subjecting a pressure-sensitive adhesive composition containing a part to a peroxide crosslinking treatment, wherein the gel fraction after crosslinking of the pressure-sensitive adhesive layer is 35 to 90% by weight. A pressure-sensitive adhesive layer for members.   100 parts by weight of an acrylic polymer containing at least 50% by weight of an acrylic ester having an alkyl group having 4 or more carbon atoms as a monomer unit, 0.02 to 2 parts by weight of a peroxide, 0.01 to 1 weight of a silane coupling agent A pressure-sensitive adhesive layer formed by subjecting a pressure-sensitive adhesive composition containing 0.01 to 5 parts by weight of a crosslinking agent (excluding peroxide) to peroxide crosslinking treatment, the pressure-sensitive adhesive layer A pressure-sensitive adhesive layer for an optical member having a gel fraction of 35 to 90% by weight after the crosslinking treatment.   The pressure-sensitive adhesive layer for an optical member according to claim 1 or 2, wherein the acrylic polymer has a weight average molecular weight of 1,000,000 or more. The optical member with an adhesive in which the adhesive layer for optical members in any one of Claims 1-3 is formed in the single side | surface or both surfaces of an optical member. An image display device using at least one optical member with an adhesive according to claim 4.