JP2018028974A - Adhesive composition for organic el display device, adhesive layer for organic el display device, polarizing film with adhesive layer for organic el display device, and organic el display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition for a bent type organic EL display device, from which such an adhesive layer for the bent type organic EL display device can be formed that can be used for the bendable organic EL display device and thereby suppresses deterioration of an organic EL element, shows excellent flexibility without inducing breakage, peeling or fracture when folded (bent), suppresses bleed-out of an ultraviolet ray absorbent in the adhesive layer and has excellent contamination prevention property, the adhesive layer, a polarizing film with the adhesive layer, and the organic EL display device having the adhesive layer.SOLUTION: The adhesive composition for a flexible organic EL display device comprises a base polymer containing a monofunctional monomer as a monomer component, an ultraviolet ray absorbent, and a dye compound having a maximum absorption wavelength in an absorption spectrum present in the wavelength region from 380 to 430 nm. The composition contains the ultraviolet ray absorbent and the dye compound by 0.1 to 15 pts.wt. in total with respect to 100 pts.wt. of the monofunctional monomer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pressure-sensitive adhesive composition for a folding type (flexible) organic EL (electroluminescence) display device (OLED). Moreover, this invention relates to the polarizing film with an adhesive layer which has the adhesive layer for bending type organic EL display devices formed from the said adhesive composition for bending type organic EL display devices, and the said adhesive layer. Furthermore, the present invention relates to a folding organic EL display device using the pressure-sensitive adhesive layer or the polarizing film with the pressure-sensitive adhesive layer.

  In recent years, organic EL display devices equipped with organic EL panels have been widely used in various applications such as mobile phones, car navigation devices, personal computer monitors, and televisions. In general, an organic EL display device has a circularly polarizing plate (polarizing plate 1 and a polarizing plate 1) on a surface on the viewing side of an organic EL panel in order to prevent external light from being reflected by a metal electrode (cathode) and viewed like a mirror surface. / 4 wavelength plate laminate or the like) is disposed. Moreover, a decorative panel etc. may be further laminated | stacked on the circularly-polarizing plate laminated | stacked on the visual recognition side surface of the organic EL panel. The constituent members of the organic EL display device such as the circularly polarizing plate and the decorative panel are usually laminated via a bonding material such as an adhesive layer and an adhesive layer.

  In an image display device such as an organic EL display device, a component or the like in the image display device may be deteriorated by incident ultraviolet light, and a layer containing an ultraviolet absorber in order to suppress deterioration due to the ultraviolet light. It is known to provide Specifically, for example, it has at least one ultraviolet absorbing layer, the light transmittance at a wavelength of 380 nm is 30% or less, and the visible light transmittance at a wavelength longer than the wavelength of 430 nm is 80% or more. Transparent double-sided pressure-sensitive adhesive sheets for image display devices (for example, see Patent Document 1) and pressure-sensitive adhesive sheets having a pressure-sensitive adhesive layer containing an acrylic polymer and a triazine-based ultraviolet absorber are known (for example, see Patent Document 2). .

JP 2012-211305 A JP 2013-75978 A

  The pressure-sensitive adhesive sheets described in Patent Documents 1 and 2 can control the transmittance of light having a wavelength of 380 nm. When the pressure-sensitive adhesive sheet is used in an organic EL display device, the organic EL element can be used over a long period of time. May deteriorate and was not sufficient. This is because the pressure-sensitive adhesive sheets described in Patent Documents 1 and 2 can absorb light having a wavelength of 380 nm, but the wavelength region on the shorter wavelength side (380 nm) than the light emitting region of the organic EL element (longer wavelength side than 430 nm). (˜430 nm) is not sufficiently absorbed, and it is considered that the transmitted light deteriorates.

  Therefore, in order to suppress deterioration of the organic EL element, transmission of light having a wavelength (380 nm to 430 nm) shorter than the light emitting region (longer wavelength side than 430 nm) of the organic EL element is suppressed. Therefore, it is necessary to use a layer having a high transparency that can sufficiently ensure the transmittance of visible light in the light emitting region of the organic EL display device.

  In recent years, organic EL display devices and the like are also required to be foldable organic EL display devices, and in order to bend (bend), there is a strong demand for weight reduction and thinning. The polarizing film used is also expected to be thinner and lighter.

  However, along with the thinning of optical films such as polarizing films, the use of a large amount of UV absorbers contained in the adhesive layer reduces the plasticity of the film, and when bending (bending) an organic EL display device, etc. Additives such as ultraviolet absorbers easily move, bleed out, the adhesive layer itself becomes hard, and the organic EL display device becomes difficult to bend, and breakage, peeling, breakage and the like are likely to occur.

  Therefore, the present invention can be used in a bendable organic EL display device to suppress deterioration of the organic EL element, and is not bent, peeled off, bent, or the like during bending (bending). Folding type organic EL display that can form a pressure-sensitive adhesive layer for a foldable organic EL display device that is excellent in the properties and further suppresses bleed-out of ultraviolet absorbers and the like in the pressure-sensitive adhesive layer and has excellent contamination resistance It aims at providing the adhesive composition for apparatuses. Moreover, a polarizing film with a pressure-sensitive adhesive layer for a folding organic EL display device, comprising a pressure-sensitive adhesive layer for a folding organic EL display device, a polarizing film, and a pressure-sensitive adhesive layer for a folding organic EL display device formed from the pressure-sensitive adhesive composition. An object of the present invention is to provide a foldable organic EL display device comprising the pressure-sensitive adhesive layer or the polarizing film with the pressure-sensitive adhesive layer.

  As a result of intensive studies to solve the above problems, the present inventors have found the following pressure-sensitive adhesive composition for organic EL display devices and have completed the present invention.

  That is, the pressure-sensitive adhesive composition for a folded organic EL display device of the present invention includes a base polymer containing a monofunctional monomer as a monomer component, an ultraviolet absorber, and a wavelength having a maximum absorption wavelength of 380 to 430 nm. A pressure-sensitive adhesive composition for a folding organic EL display device comprising a dye compound present in a region, wherein the ultraviolet absorber and the dye compound are combined in a total amount of 0.1 parts by weight with respect to 100 parts by weight of the monofunctional monomer. It contains 1 to 15 parts by weight.

  In the folding organic EL display device pressure-sensitive adhesive composition of the present invention, the base polymer is preferably a (meth) acrylic polymer.

  The pressure-sensitive adhesive composition for a folding organic EL display device of the present invention preferably contains an ionic compound.

  The pressure-sensitive adhesive composition for a folding organic EL display device of the present invention preferably contains a peroxide-based crosslinking agent.

  The pressure-sensitive adhesive layer for a folding organic EL display device of the present invention is preferably formed from the pressure-sensitive adhesive composition for a folding organic EL display device.

The pressure-sensitive adhesive layer for a folding organic EL display device of the present invention preferably has a surface resistance value of 1 × 10 ¹² Ω / □ or less.

  The polarizing film with a pressure-sensitive adhesive layer for a folding organic EL display device of the present invention preferably has a polarizing film and the pressure-sensitive adhesive layer for a folding organic EL display device.

  The polarizing film with a pressure-sensitive adhesive layer for a folding organic EL display device of the present invention preferably has a conductive layer between the polarizing film and the pressure-sensitive adhesive layer for the folding organic EL display device.

  The folding organic EL display device of the present invention preferably uses at least one of the pressure-sensitive adhesive layer for the folding organic EL display device or the polarizing film with the pressure-sensitive adhesive layer for the folding organic EL display device.

  The pressure-sensitive adhesive composition for a folding organic EL display device of the present invention can be used for an organic EL display device to suppress deterioration of the organic EL element, and at the time of bending (bending), it is ruptured, peeled off or folded. It is possible to form a pressure-sensitive adhesive layer for a foldable organic EL display device that is superior in flex resistance, further suppresses bleed-out of ultraviolet absorbers and the like in the pressure-sensitive adhesive layer, and has excellent contamination resistance. it can. Therefore, the folding type organic EL using the pressure-sensitive adhesive layer for the folding type organic EL display device of the present invention or the polarizing film with the pressure sensitive adhesive layer for the folding type organic EL display device including the pressure sensitive adhesive layer for the folding type organic EL display device. The display device has excellent weather resistance and can have a long life.

It is sectional drawing which shows typically one Embodiment of the polarizing film with an adhesive layer for bending type organic EL display apparatuses of this invention. It is sectional drawing which shows typically one Embodiment of the polarizing film with an adhesive layer for bending type organic EL display apparatuses of this invention. It is sectional drawing which shows typically one Embodiment of the polarizing film with an adhesive layer for bending type organic EL display apparatuses of this invention. It is sectional drawing which shows typically one Embodiment of the bending type organic electroluminescent display apparatus of this invention. It is sectional drawing which shows typically one Embodiment of the bending type organic electroluminescent display apparatus of this invention. It is sectional drawing which shows typically one Embodiment of the bending type organic electroluminescent display apparatus of this invention. It is a figure which shows the measuring method of a bending resistance test. It is sectional drawing which shows the sample for evaluation used in an Example.

1. Folding type organic EL display device pressure-sensitive adhesive composition Folding type organic EL display device pressure-sensitive adhesive composition of the present invention (hereinafter simply referred to as "organic EL display device pressure-sensitive adhesive composition" or "pressure-sensitive adhesive composition") Is a foldable type comprising, as a monomer component, a base polymer containing a monofunctional monomer, an ultraviolet absorber, and a dye compound having a maximum absorption wavelength in the absorption spectrum of 380 to 430 nm. A pressure-sensitive adhesive composition for an organic EL display device, comprising 0.1 to 15 parts by weight as a total amount of the ultraviolet absorber and the dye compound with respect to 100 parts by weight of the monofunctional monomer. And Here, the maximum absorption wavelength means an absorption maximum wavelength exhibiting the maximum absorbance among the plurality of absorption maximums in the spectral absorption spectrum in the wavelength region of 300 to 460 nm. .

  The base polymer used in the present invention is not particularly limited. Examples of the pressure-sensitive adhesive composition include rubber-based adhesives, acrylic-based adhesives, silicone-based adhesives, urethane-based adhesives, and vinyl alkyls. Examples thereof include ether-based adhesives, polyvinyl alcohol-based adhesives, polyvinylpyrrolidone-based adhesives, polyacrylamide-based adhesives, and cellulose-based adhesives. Among these pressure-sensitive adhesives, acrylic pressure-sensitive adhesives are preferably used because they are excellent in optical transparency, exhibit appropriate adhesiveness, cohesiveness, and adhesive pressure-sensitive adhesive properties, and are excellent in weather resistance, heat resistance, and the like. . In the present invention, an acrylic pressure-sensitive adhesive composition containing a (meth) acrylic polymer as a base polymer is preferable.

  The acrylic pressure-sensitive adhesive composition includes, for example, a partial polymer of a monomer component containing an alkyl (meth) acrylate and / or a (meth) acrylic polymer obtained from the monomer component, an ultraviolet absorber and a dye compound. It is preferable.

(1) Partially polymerized monomer component and (meth) acrylic polymer The acrylic pressure-sensitive adhesive composition is obtained from a partially polymerized monomer component containing alkyl (meth) acrylate and / or the monomer component ( Contains a (meth) acrylic polymer.

  Examples of the alkyl (meth) acrylate include those having a linear or branched alkyl group having 1 to 24 carbon atoms at the ester terminal. Alkyl (meth) acrylate can be used individually by 1 type or in combination of 2 or more types. “Alkyl (meth) acrylate” refers to alkyl acrylate and / or alkyl methacrylate, and (meth) in the present invention has the same meaning.

  Examples of the alkyl (meth) acrylate include the aforementioned linear or branched alkyl (meth) acrylate having 1 to 24 carbon atoms. Among these, a C1-C9 alkyl (meth) acrylate is preferable, a C4-C8 alkyl (meth) acrylate is more preferable, and a C4-C8 branched alkyl (meth) acrylate is further more preferable. . The alkyl (meth) acrylate is preferable in terms of easily balancing the adhesive properties. For example, as an alkyl (meth) acrylate having 4 to 8 carbon atoms, specifically, n-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate , N-pentyl (meth) acrylate, isopentyl (meth) acrylate, isohexyl (meth) acrylate, isoheptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, and the like. Or two or more types can be used in combination.

  In the present invention, the alkyl (meth) acrylate having a linear or branched alkyl group having 1 to 24 carbon atoms at the ester terminal is used in the total amount of the monofunctional monomer component forming the (meth) acrylic polymer. On the other hand, it is preferably 40% by weight or more, more preferably 50% by weight or more, and further preferably 60% by weight or more.

  The monomer component may contain a copolymerization monomer other than the alkyl (meth) acrylate as a monofunctional monomer component. A copolymerization monomer can be used as the remainder of the said alkyl (meth) acrylate in a monomer component.

  As the copolymerization monomer, for example, a cyclic nitrogen-containing monomer can be included. As said cyclic nitrogen containing monomer, what has a polymerizable functional group which has unsaturated double bonds, such as a (meth) acryloyl group or a vinyl group, and has a cyclic nitrogen structure can be especially used without a restriction | limiting. The cyclic nitrogen structure preferably has a nitrogen atom in the cyclic structure. Examples of cyclic nitrogen-containing monomers include lactam vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone; vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinyl Examples thereof include vinyl monomers having a nitrogen-containing heterocyclic ring such as imidazole, vinyl oxazole and vinyl morpholine. Moreover, the (meth) acryl monomer containing heterocyclic rings, such as a morpholine ring, a piperidine ring, a pyrrolidine ring, a piperazine ring, is mentioned. Specific examples include N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, N-acryloylpyrrolidine and the like. Among the cyclic nitrogen-containing monomers, lactam vinyl monomers are preferable.

  In the present invention, the cyclic nitrogen-containing monomer is preferably 0.5 to 50% by weight, and preferably 0.5 to 40% by weight, based on the total amount of the monofunctional monomer component forming the (meth) acrylic polymer. Is more preferable, and 0.5 to 30% by weight is further preferable.

  The monomer component used in the present invention can contain a hydroxyl group-containing monomer as a monofunctional monomer component. As the hydroxyl group-containing monomer, a monomer having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and having a hydroxyl group can be used without particular limitation. Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl ( Hydroxyalkyl (meth) acrylates such as (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate; -Hydroxyalkylcycloalkane (meth) acrylates such as -hydroxymethylcyclohexyl) methyl (meth) acrylate. Other examples include hydroxyethyl (meth) acrylamide, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, and the like. These can be used alone or in combination. Of these, hydroxyalkyl (meth) acrylate is preferred.

  In the present invention, the hydroxyl group-containing monomer is preferably 1% by weight or more from the viewpoint of enhancing adhesive force and cohesive force with respect to the total amount of the monofunctional monomer component forming the (meth) acrylic polymer, It is more preferably 2% by weight or more, and further preferably 3% by weight or more. On the other hand, if the amount of the hydroxyl group-containing monomer is too large, the pressure-sensitive adhesive layer becomes hard and the adhesive strength may decrease, and the viscosity of the pressure-sensitive adhesive may become too high or gel. The hydroxyl group-containing monomer is preferably 30% by weight or less, more preferably 27% by weight or less, and more preferably 25% by weight or less based on the total amount of the monofunctional monomer component forming the (meth) acrylic polymer. Is more preferable.

  In addition, the monomer component that forms the (meth) acrylic polymer can contain other functional group-containing monomers as monofunctional monomers, such as carboxyl group-containing monomers and monomers having a cyclic ether group. It is done.

  As the carboxyl group-containing monomer, those having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and having a carboxyl group can be used without particular limitation. Examples of the carboxyl group-containing monomer include (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid. Can be used alone or in combination. These anhydrides can be used for itaconic acid and maleic acid. Among these, acrylic acid and methacrylic acid are preferable, and acrylic acid is particularly preferable. In addition, a carboxyl group-containing monomer can be arbitrarily used for the monomer component used for manufacture of the (meth) acrylic-type polymer of this invention, On the other hand, it is not necessary to use a carboxyl group-containing monomer.

  As a monomer having a cyclic ether group, a monomer having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and a cyclic ether group such as an epoxy group or an oxetane group. It can be used without particular limitation. Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether, and the like. Examples of the oxetane group-containing monomer include 3-oxetanylmethyl (meth) acrylate, 3-methyl-oxetanylmethyl (meth) acrylate, 3-ethyl-oxetanylmethyl (meth) acrylate, and 3-butyl-oxetanylmethyl (meth) acrylate. , 3-hexyl-oxetanylmethyl (meth) acrylate and the like. These can be used alone or in combination.

  In the present invention, the carboxyl group-containing monomer and the monomer having a cyclic ether group are preferably 30% by weight or less based on the total amount of the monofunctional monomer component forming the (meth) acrylic polymer, and 27% by weight. % Or less is more preferable, and 25% by weight or less is more preferable.

The monomer component forming the (meth) acrylic polymer of the present invention includes, for example, CH ₂ ═C (R ¹ ) COOR ² (wherein R ¹ is hydrogen or a methyl group, and R ² is the number of carbon atoms). An alkyl (meth) acrylate represented by 1 to 3 substituted alkyl groups and a cyclic cycloalkyl group.

Here, the substituent of the substituted alkyl group having 1 to 3 carbon atoms as R ² is preferably an aryl group having 3 to 8 carbon atoms or an aryloxy group having 3 to 8 carbon atoms. . The aryl group is not limited, but is preferably a phenyl group.

Examples of such a monomer represented by CH ₂ ═C (R ¹ ) COOR ² include phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, 3,3,5-trimethylcyclohexyl. (Meth) acrylate, isobornyl (meth) acrylate, etc. are mentioned. These can be used alone or in combination.

In the present invention, the (meth) acrylate represented by CH ₂ ═C (R ¹ ) COOR ² is 50% by weight or less based on the total amount of the monofunctional monomer component forming the (meth) acrylic polymer. 45% by weight or less is preferable, 40% by weight or less is more preferable, and 35% by weight or less is more preferable.

  Other copolymer monomers include vinyl acetate, vinyl propionate, styrene, α-methylstyrene; (meth) acrylic acid polyethylene glycol, (meth) acrylic acid polypropylene glycol, (meth) acrylic acid methoxyethylene glycol, (meth) Glycol acrylic ester monomers such as methoxypolypropylene glycol acrylate; Acrylic ester monomers such as tetrahydrofurfuryl (meth) acrylate, fluorine (meth) acrylate, silicone (meth) acrylate and 2-methoxyethyl acrylate; Monomers, amino group-containing monomers, imide group-containing monomers, N-acryloylmorpholine, vinyl ether monomers, and the like can also be used. Moreover, as a copolymerization monomer, the monomer which has cyclic structures, such as terpene (meth) acrylate and dicyclopentanyl (meth) acrylate, can be used.

  Furthermore, the silane type monomer etc. which contain a silicon atom are mentioned. Examples of the silane monomer include 3-acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, and 8-vinyloctyltrimethoxysilane. , 8-vinyloctyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltriethoxysilane, 10-acryloyloxydecyltriethoxysilane, and the like.

  The monomer component that forms the (meth) acrylic polymer of the present invention contains a polyfunctional monomer as necessary in order to adjust the cohesive strength of the pressure-sensitive adhesive, in addition to the monofunctional monomer exemplified above. be able to.

  The production of the (meth) acrylic polymer can be appropriately selected from known production methods such as radiation polymerization such as solution polymerization, ultraviolet (UV) polymerization, various radical polymerizations such as bulk polymerization and emulsion polymerization. Further, the (meth) acrylic polymer obtained may be any of a random copolymer, a block copolymer, a graft copolymer, and the like.

  In the present invention, a partial polymer of the monomer component can also be suitably used.

  When the (meth) acrylic polymer is produced by radical polymerization, polymerization can be carried out by appropriately adding a polymerization initiator, a chain transfer agent, an emulsifier and the like used for radical polymerization to the monomer component. The polymerization initiator, chain transfer agent, emulsifier and the like used for the radical polymerization are not particularly limited and can be appropriately selected and used. In addition, the weight average molecular weight of a (meth) acrylic-type polymer can be controlled by the usage-amount of a polymerization initiator and a chain transfer agent, and reaction conditions, and the usage-amount is suitably adjusted according to these kinds.

  For example, in solution polymerization or the like, for example, ethyl acetate, toluene or the like is used as a polymerization solvent. As a specific example of solution polymerization, the reaction is performed under an inert gas stream such as nitrogen and a polymerization initiator is added, and the reaction is usually performed at about 50 to 70 ° C. under reaction conditions for about 5 to 30 hours.

  Examples of the thermal polymerization initiator used for solution polymerization include 2,2′-azobisisobutyronitrile, 2,2′-azobis-2-methylbutyronitrile, 2,2′-azobis (2 -Methylpropionic acid) dimethyl, 4,4'-azobis-4-cyanovaleric acid, azobisisovaleronitrile, 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′-dimethyleneisobutyl) Amidine), 2,2′-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate (VA-057, Wako Pure Chemical Industries, Ltd.) Azo-based initiators such as potassium persulfate and ammonium persulfate, di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-sec -Butyl peroxydicarbonate, t-butyl peroxyneodecanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, 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-hexyl) Peroxy) cyclohexane, t-butyl hydroperoxide, hydrogen peroxide, etc. Compound initiators, combinations of persulfates and sodium bisulfite, redox initiators combining peroxides and reducing agents such as combinations of peroxides and sodium ascorbate, etc. It is not limited.

  The polymerization initiator may be used alone or in combination of two or more, but is preferably about 1 part by weight or less with respect to 100 parts by weight of the total amount of monomer components. The amount is more preferably about 0.005 to 1 part by weight, and still more preferably about 0.02 to 0.5 part by weight.

  When 2,2′-azobisisobutyronitrile is used as the polymerization initiator, the amount of the polymerization initiator used is about 0.2 parts by weight or less with respect to 100 parts by weight of the total amount of monomer components. The amount is preferably about 0.06 to 0.2 parts by weight.

  Examples of the chain transfer agent include lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, and 2,3-dimercapto-1-propanol. The chain transfer agent may be used alone or in combination of two or more, but the total content is 0.3 parts by weight relative to 100 parts by weight of the total amount of monomer components. Less than or equal to

  Examples of the emulsifier used in emulsion polymerization include anionic emulsifiers such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, ammonium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkylphenyl 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.), Adeka Soap SE10N (manufactured by ADEKA), and the like. The amount of the emulsifier used is preferably 5 parts by weight or less with respect to 100 parts by weight of the total amount of the monomer components.

  In the present invention, when the (meth) acrylic polymer is used, those having a weight average molecular weight (Mw) in the range of 500,000 to 2.5 million are usually used. In consideration of durability, particularly heat resistance and flexibility, it is preferably 800,000 to 2,200,000, more preferably 1,000,000 to 2,000,000. When the weight average molecular weight is less than 500,000, the number of crosslinking points increases and the flexibility of the pressure-sensitive adhesive is lost, which is not preferable in terms of heat resistance and flexibility. Further, if the weight average molecular weight is larger than 2.5 million, a large amount of a diluent solvent is required to adjust the viscosity for coating, and this is not preferable because it increases the cost. The flexibility of the polymer is inferior, which is not preferable. The weight average molecular weight (Mw) is a value measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene.

(2) Ultraviolet absorber The ultraviolet absorber is not particularly limited. For example, a triazine ultraviolet absorber, a benzotriazole ultraviolet absorber, a benzophenone ultraviolet absorber, an oxybenzophenone ultraviolet absorber, or a salicylic acid ester ultraviolet ray. An absorber, a cyanoacrylate type ultraviolet absorber, etc. can be mentioned, These can be used individually by 1 type or in combination of 2 or more types. Among these, triazine-based UV absorbers and benzotriazole-based UV absorbers are preferable, triazine-based UV absorbers having 2 or less hydroxyl groups in one molecule, and benzones having one benzotriazole skeleton in one molecule. It is at least one ultraviolet absorber selected from the group consisting of triazole-based ultraviolet absorbers, has good solubility in monomers used for forming an acrylic pressure-sensitive adhesive composition, and has a wavelength of around 380 nm This is preferable because of its high ultraviolet absorption ability.

  Specific examples of the triazine-based ultraviolet absorber having two or less hydroxyl groups in one molecule include 2,4-bis-[{4- (4-ethylhexyloxy) -4-hydroxy} -phenyl] -6. -(4-Methoxyphenyl) -1,3,5-triazine (Tinosorb S, manufactured by BASF), 2,4-bis [2-hydroxy-4-butoxyphenyl] -6- (2,4-dibutoxyphenyl) -1,3,5-triazine (TINUVIN 460, manufactured by BASF), 2- (4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl) -5-hydroxyphenyl And [(C10-C16 (mainly C12-C13) alkyloxy) methyl] oxirane reaction product (TINUVIN400, manufactured by BASF), 2- [4,6-bis (2, -Dimethylphenyl) -1,3,5-triazin-2-yl] -5- [3- (dodecyloxy) -2-hydroxypropoxy] phenol), 2- (2,4-dihydroxyphenyl) -4,6 -Reaction product of bis- (2,4-dimethylphenyl) -1,3,5-triazine and (2-ethylhexyl) -glycidic acid ester (TINUVIN405, manufactured by BASF), 2- (4,6-diphenyl-1 , 3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol (TINUVIN 1577, manufactured by BASF), 2- (4,6-diphenyl-1,3,5-triazin-2-yl)- 5- [2- (2-Ethylhexanoyloxy) ethoxy] -phenol (ADK STAB LA46, manufactured by ADEKA), 2- (2-hydroxy-4- [ - octyloxycarbonylethoxy] phenyl) -4,6-bis (4-phenylphenyl) -1,3,5-triazine (TINUVIN 479, manufactured by BASF), and the like.

  Moreover, as a benzotriazole ultraviolet absorber having one benzotriazole skeleton in one molecule, 2- (2H-benzotriazol-2-yl) -6- (1-methyl-1-phenylethyl) -4- (1,1,3,3-tetramethylbutyl) phenol (TINUVIN 928, manufactured by BASF), 2- (2-hydroxy-5-tert-butylphenyl) -2H-benzotriazole (TINUVIN PS, manufactured by BASF), benzene Propanoic acid and ester compounds of 3- (2H-benzotriazol-2-yl) -5- (1,1-dimethylethyl) -4-hydroxy (C7-9 side chain and linear alkyl) (TINUVIN 384-2, BASF) Manufactured), 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenyl) Ethyl) phenol (TINUVIN900, manufactured by BASF), 2- (2H-benzotriazol-2-yl) -6- (1-methyl-1-phenylethyl) -4- (1,1,3,3-tetramethylbutyl) ) Phenol (TINUVIN 928, manufactured by BASF), methyl-3- (3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate / polyethylene glycol 300 reaction product (TINUVIN 1130, BASF), 2- (2H-benzotriazol-2-yl) -p-cresol (TINUVIN P, manufactured by BASF), 2 (2H-benzotriazol-2-yl) -4-6-bis (1-methyl- 1-phenylethyl) phenol (TINUVIN234, manufactured by BASF), 2- [5- (2H) -benzotriazol-2-yl] -4-methyl-6- (tert-butyl) phenol (TINUVIN 326, manufactured by BASF), 2- (2H-benzotriazol-2-yl) -4,6-di -Tert-pentylphenol (TINUVIN 328, manufactured by BASF), 2- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol (TINUVIN 329, manufactured by BASF), methyl 3 -(3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate and polyethylene glycol 300 reaction product (TINUVIN 213, manufactured by BASF), 2- (2H-benzotriazole -2-yl) -6-dodecyl-4-methylphenol (TI NUVIN571, manufactured by BASF), 2- [2-hydroxy-3- (3,4,5,6-tetrahydrophthalimido-methyl) -5-methylphenyl] benzotriazole (Sumsorb 250, manufactured by Sumitomo Chemical Co., Ltd.), etc. Can be mentioned.

  Examples of the benzophenone ultraviolet absorber (benzophenone compound) and oxybenzophenone ultraviolet absorber (oxybenzophenone compound) include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, and 2-hydroxy. -4-methoxybenzophenone-5-sulfonic acid (anhydrous and trihydrate), 2-hydroxy-4-octyloxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 4-benzyloxy-2-hydroxybenzophenone, 2, Examples include 2 ', 4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4,4-dimethoxybenzophenone.

  Examples of the salicylic acid ester ultraviolet absorber (salicylic acid ester compound) include, for example, phenyl-2-acryloyloxybenzoate, phenyl-2-acryloyloxy-3-methylbenzoate, and phenyl-2-acryloyl. Oxy-4-methylbenzoate, phenyl-2-acryloyloxy-5-methylbenzoate, phenyl-2-acryloyloxy-3-methoxybenzoate, phenyl-2-hydroxybenzoate, phenyl-2- Hydroxy-3-methylbenzoate, phenyl-2-hydroxy-4methylbenzoate, phenyl-2-hydroxy-5-methylbenzoate, phenyl 2-hydroxy-3-methoxybenzoate, 2,4-di- tert-Butylphenyl-3,5-di-tert- Chill-4-hydroxybenzoate (TINUVIN120, manufactured by BASF), and the like.

  Examples of the cyanoacrylate ultraviolet absorber (cyanoacrylate compound) include alkyl-2-cyanoacrylate, cycloalkyl-2-cyanoacrylate, alkoxyalkyl-2-cyanoacrylate, alkenyl-2-cyanoacrylate, alkynyl- Examples include 2-cyanoacrylate.

  The maximum absorption wavelength of the absorption spectrum of the ultraviolet absorber is preferably in the wavelength region of 300 to 400 nm, and more preferably in the wavelength region of 320 to 380 nm. The measuring method of the maximum absorption wavelength is the same as the measuring method of the dye-based compound described later.

  The said ultraviolet absorber may be used independently, and may mix and use 2 or more types. In addition, as a compounding quantity of the said ultraviolet absorber, Preferably it is 0.09-5 weight part with respect to 100 weight part of said monofunctional monomers, and 0.5-3 weight part is more preferable.

(3) Dye Compound The dye compound used in the present invention is not particularly limited as long as it is a compound having a maximum absorption wavelength of an absorption spectrum in a wavelength region of 380 to 430 nm. The maximum absorption wavelength of the absorption spectrum of the dye compound is more preferably in the wavelength region of 380 to 420 nm. In the present invention, by using a combination of such a dye compound and the ultraviolet absorber, light in a region (wavelength 380 nm to 430 nm) that does not affect the light emission of the organic EL element can be sufficiently absorbed, and The light emitting region of the organic EL element (longer wavelength side than 430 nm) can be sufficiently transmitted, and as a result, deterioration of the organic EL element due to external light can be suppressed.

The half width of the dye compound is not particularly limited, but is preferably 80 nm or less, more preferably 5 to 70 nm, and still more preferably 10 to 60 nm. When the half-value width of the dye compound is in the above range, it is possible to control to sufficiently transmit light having a wavelength longer than 430 nm while sufficiently absorbing light in a region that does not affect light emission of the organic EL element. Therefore, it is preferable. In addition, the measuring method of a half value width is based on the method as described below.
<Measurement method of half width>
The full width at half maximum of the dye compound was measured from the transmission absorption spectrum of the solution of the dye compound under the following conditions using an ultraviolet-visible spectrophotometer (U-4100, manufactured by Hitachi High-Tech Science Co., Ltd.). From the spectrum measured by adjusting the concentration so that the absorbance at the maximum absorption wavelength is 1.0, the wavelength interval (full width at half maximum) between two points at 50% of the peak value is defined as the half width of the dye compound. .
(Measurement condition)
Solvent: Toluene or chloroform Cell: Quartz cell Optical path length: 10 mm

  The dye compound is not particularly limited as long as it is a compound having a maximum absorption wavelength of an absorption spectrum in a wavelength region of 380 to 430 nm. Examples of the dye compound include an organic dye compound and an inorganic dye compound. Among these, an organic dye is used from the viewpoint of maintaining dispersibility in a resin component such as a base polymer and transparency. Compounds are preferred.

  Examples of the organic dye compound include azomethine compounds, indole compounds, cinnamic acid compounds, pyrimidine compounds, porphyrin compounds, and the like.

  As the organic dye compound, a commercially available product can be suitably used. Specifically, as the indole compound, BONASORB UA3911 (trade name, maximum absorption wavelength of absorption spectrum: 398 nm, half-value width: 48 nm, manufactured by Orient Chemical Industry Co., Ltd.), BONASORB UA3912 (trade name, maximum absorption wavelength of absorption spectrum: 386 nm, half width: 53 nm, manufactured by Orient Chemical Industry Co., Ltd.), and cinnamate compounds as SOM -5-0106 (trade name, absorption spectrum maximum absorption wavelength: 416 nm, full width at half maximum: 50 nm, manufactured by Orient Chemical Industry Co., Ltd.), pyrimidine compounds as FDB-009 (trade name, absorption spectrum maximum absorption wavelength : 394 nm, half width: 43 nm, manufactured by Yamada Chemical Co., Ltd.), Porphy Examples of the phosphorus compound include FDB-001 (trade name, maximum absorption wavelength of absorption spectrum: 420 nm, full width at half maximum: 14 nm, manufactured by Yamada Chemical Co., Ltd.), and the like.

  The dye compounds may be used alone or in combination of two or more. In addition, as a compounding quantity of the said pigment compound, Preferably it is 0.01-10 weight part with respect to 100 weight part of said monofunctional monomers, More preferably, it is 0.02-5 weight part.

  Moreover, as a total amount of the said ultraviolet absorber and the said pigment | dye compound, it contains 0.1-15 weight part with respect to 100 weight part of said monofunctional monomers, Preferably, it is 1-15 weight part, More Preferably, it is 2 to 14 parts by weight, and more preferably 3 to 13 parts by weight. By setting it as the above-mentioned range, the ultraviolet ray absorbing function of the pressure-sensitive adhesive layer can be sufficiently exhibited, and ultraviolet polymerization is preferable because it does not hinder the polymerization. Moreover, the light of the area | region which does not influence the light emission of an organic EL element can fully be absorbed, and deterioration of an organic EL display element can be suppressed by using the adhesive layer formed from the said adhesive composition. It is possible and preferable. Furthermore, by making it within the above range, at the time of bending (bending), it is possible to suppress bleed-out such as an ultraviolet absorber, and is excellent in stain resistance, and the adhesive layer itself does not become hard, and can be easily bent. It is excellent in flex resistance and is preferable. When the amount exceeds 15 parts by weight, particularly when a bending test is performed under a wet heat test, the ultraviolet absorber or the like tends to bleed out, and the color tends to deteriorate.

(4) Silane coupling agent Furthermore, the foldable organic EL display device pressure-sensitive adhesive composition of the present invention may contain a silane coupling agent. The amount of the silane coupling agent is preferably 1 part by weight or less, more preferably 0.01 to 1 part by weight, based on 100 parts by weight of the monofunctional monomer component forming the (meth) acrylic polymer. More preferred is 02 to 0.6 parts by weight.

  Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2- (3,4 epoxycyclohexyl). Epoxy group-containing silane coupling agents such as ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1, (3-dimethylbutylidene) propylamine, amino group-containing silane coupling agents such as N-phenyl-γ-aminopropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane ( (Meth) acrylic group-containing silane Coupling agent, 3-isocyanate propyltriethoxysilane isocyanate group-containing silane coupling agents such as and the like.

(5) Crosslinking agent The pressure-sensitive adhesive composition for a folding organic EL display device of the present invention may contain a crosslinking agent. As the crosslinking agent, an organic crosslinking agent or a polyfunctional metal chelate can be used. Examples of the organic crosslinking agent include an isocyanate crosslinking agent, a peroxide crosslinking agent, an epoxy crosslinking agent, and an imine crosslinking agent. A polyfunctional metal chelate is one in which a polyvalent metal is covalently or coordinately bonded to an organic compound. Examples of polyvalent metal atoms include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, Ti, and the like. Can be mentioned. Examples of the atom in the organic compound to be covalently bonded or coordinated include an oxygen atom, and examples of the organic compound include alkyl esters, alcohol compounds, carboxylic acid compounds, ether compounds, and ketone compounds. Among these, an isocyanate type crosslinking agent and / or a peroxide type crosslinking agent are preferably used. Isocyanate-based crosslinking agents are preferable from the viewpoint of durability, and peroxide-based crosslinking agents are preferable from the viewpoint of crosslinking speed and flexibility.

  For example, the blending amount of the crosslinking agent is preferably 0.01 to 5 parts by weight and more preferably 0.03 to 2 parts by weight with respect to 100 parts by weight of the (meth) acrylic polymer. If it is within the above range, it is excellent in bending resistance and becomes a preferred embodiment.

(6) Ionic Compound The pressure-sensitive adhesive composition of the present invention can contain an ionic compound. By using an ionic compound, excellent antistatic properties can be imparted. In particular, the surface resistance value of the pressure-sensitive adhesive layer surface can be kept low, which is advantageous. In addition, as an ionic compound, an alkali metal salt and / or an organic cation-anion salt can be preferably used. As the alkali metal salt, an organic salt or inorganic salt of an alkali metal can be used. The “organic cation-anion salt” in the present invention refers to an organic salt whose cation part is composed of an organic substance, and the anion part may be an organic substance or an inorganic substance. There may be. “Organic cation-anion salt” is also called an ionic liquid or ionic solid.

<Alkali metal salt>
Examples of the alkali metal ions constituting the cation part of the alkali metal salt include lithium, sodium, and potassium ions. Of these alkali metal ions, lithium ions are preferred.

The anion part of the alkali metal salt may be composed of an organic material or an inorganic material. Examples of the anion part constituting the organic salt include CH ₃ COO ⁻ , CF ₃ COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , and C ₄ F ₉ SO _{3. ^{-, C 3 F 7 COO -}} , (CF 3 SO 2) (CF 3 CO) N -, - O 3 S (CF 2) 3 SO 3 -, PF 6 -, CO 3 2-, or the following general formula ( 1) to (4),
(1): (C _n F _{2n + 1} SO ₂ ) ₂ N ⁻ (where n is an integer of 1 to 10),
_{(2): CF 2 (C} m F 2m SO 2) 2 N - ( where, m is an integer of from 1 to 10),
^{_{(3): - O 3 S}} (CF 2) l SO 3 - ( where, l is an integer of from 1 to 10),
^{_{(4) :( C p F 2p}} + 1 SO 2) N - (C q F 2q + 1 SO 2), ( where, p, q is an integer of from 1 to 10), in represented by those such as are used. In particular, an anion moiety containing a fluorine atom is preferably used because an ionic compound having good ion dissociation properties can be obtained. The anion part constituting the inorganic salt includes Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , NO ₃ ⁻ , AsF ₆ ⁻ , SbF. ₆ ⁻ , NbF ₆ ⁻ , TaF ₆ ⁻ , (CN) ₂ N ⁻ , and the like are used. As the anion moiety, (perfluoroalkylsulfonyl) imide represented by the general formula (1) such as (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , etc. is preferable, (Trifluoromethanesulfonyl) imide represented by CF ₃ SO ₂ ) ₂ N ⁻ is preferable.

Specific examples of the alkali metal organic salt include sodium acetate, sodium alginate, sodium lignin sulfonate, sodium toluenesulfonate, LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, Li (C ₄ F ₉ SO ₂ ) ₂ N, Li (CF ₃ SO ₂ ) ₃ C, KO ₃ S (CF ₂ ) ₃ SO ₃ K, _{LiO 3 S (CF 2) 3} SO 3 K , and the like, among these _{LiCF 3 SO 3, Li (CF} 3 SO 2) 2 N, Li (C 2 F 5 SO 2) 2 N, Li (C 4 F ₉ SO ₂ ) ₂ N, Li (CF ₃ SO ₂ ) ₃ C and the like are preferable, and Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, Li (C ₄ F ₉ SO _{2) 2} Fluorine-containing lithium imide salt is more preferably equal, particularly (perfluoroalkyl sulfonyl) imide lithium salts are preferred.

  Examples of the alkali metal inorganic salt include lithium perchlorate and lithium iodide.

<Organic cation-anion salt>
The organic cation-anion salt used in the present invention is composed of a cation component and an anion component, and the cation component is composed of an organic substance. As the cation component, specifically, pyridinium cation, piperidinium cation, pyrrolidinium cation, cation having pyrroline skeleton, cation having pyrrole skeleton, imidazolium cation, tetrahydropyrimidinium cation, dihydropyrimidinium cation, Examples include pyrazolium cation, pyrazolinium cation, tetraalkylammonium cation, trialkylsulfonium cation, and tetraalkylphosphonium cation.

The anionic component, _{^{e.g., Cl -, Br -, I}} -, AlCl 4 -, Al 2 Cl 7 -, BF 4 -, PF 6 -, ClO 4 -, NO 3 -, CH 3 COO -, CF 3 COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , NbF ₆ ⁻ , TaF ₆ ⁻ , (CN) ₂ N ⁻ , C ₄ F _{^{9 SO 3 -, C 3 F}} 7 COO -, ((CF 3 SO 2) (CF 3 CO) N -, - O 3 S (CF 2) 3 SO 3 -, or the following general formula (1) to (4 ),
(1): (C _n F _{2n + 1} SO ₂ ) ₂ N ⁻ (where n is an integer of 1 to 10),
_{(2): CF 2 (C} m F 2m SO 2) 2 N - ( where, m is an integer of from 1 to 10),
_{^{(3): - O 3 S}} (CF 2) l SO 3 - ( where, l is an integer of from 1 to 10),
^{_{(4) :( C p F 2p}} + 1 SO 2) N - (C q F 2q + 1 SO 2), ( where, p, q is an integer of from 1 to 10), in represented by those such as are used. Among these, an anion component containing a fluorine atom is particularly preferably used because an ionic compound having good ion dissociation properties can be obtained.

As a specific example of the organic cation-anion salt, a compound comprising a combination of the cation component and the anion component is appropriately selected and used.
For example, 1-butylpyridinium tetrafluoroborate, 1-butylpyridinium hexafluorophosphate, 1-butyl-3-methylpyridinium tetrafluoroborate, 1-butyl-3-methylpyridinium trifluoromethanesulfonate, 1-butyl-3-methylpyridinium Bis (trifluoromethanesulfonyl) imide, 1-butyl-3-methylpyridinium bis (pentafluoroethanesulfonyl) imide, 1-hexylpyridinium tetrafluoroborate, 2-methyl-1-pyrroline tetrafluoroborate, 1-ethyl-2 -Phenylindole tetrafluoroborate, 1,2-dimethylindole tetrafluoroborate, 1-ethylcarbazole tetrafluoroborate, 1-ethyl-3-methylimidazo Um tetrafluoroborate, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium trifluoroacetate, 1-ethyl-3-methylimidazolium heptafluorobutyrate, 1-ethyl-3-methyl Imidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium perfluorobutanesulfonate, 1-ethyl-3-methylimidazolium dicyanamide, 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1- Ethyl-3-methylimidazolium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-3-methylimidazolium tris (trifluoromethanesulfonyl) methide, 1-butyl-3-methylimidazolium 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium trifluoroacetate, 1-butyl-3-methylimidazolium heptafluorobutyrate, 1-butyl-3- Methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium perfluorobutanesulfonate, 1-butyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1-hexyl-3-methylimidazolium bromide, 1 -Hexyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium tetrafluoroborate, 1-hexyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-3 -Methylimidazolium trifluoromethanesulfonate, 1-octyl-3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-2,3-dimethylimidazolium tetrafluoroborate, 1,2-dimethyl-3-propylimidazolium bis (trifluoromethanesulfonyl) imide, 1-methylpyrazolium tetrafluoroborate, 3-methylpyrazolium tetrafluoroborate, tetrahexylammonium bis (trifluoromethanesulfonyl) imide, Diallyldimethylammonium tetrafluoroborate, diallyldimethylammonium trifluoromethanesulfonate, diallyldimethylammonium bis (trifluoromethanes Phonyl) imide, diallyldimethylammonium bis (pentafluoroethanesulfonyl) imide, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium tetrafluoroborate, N, N-diethyl-N-methyl-N -(2-methoxyethyl) ammonium trifluoromethanesulfonate, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N -(2-methoxyethyl) ammonium bis (pentafluoroethanesulfonyl) imide, glycidyltrimethylammonium trifluoromethanesulfonate, glycidyltrimethylammonium bis (trifluoromethanesulfonyl) imide, glycidyl trime Ruammonium bis (pentafluoroethanesulfonyl) imide, 1-butylpyridinium (trifluoromethanesulfonyl) trifluoroacetamide, 1-butyl-3-methylpyridinium (trifluoromethanesulfonyl) trifluoroacetamide, 1-ethyl-3-methylimidazolium (Trifluoromethanesulfonyl) trifluoroacetamide, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium (trifluoromethanesulfonyl) trifluoroacetamide, diallyldimethylammonium (trifluoromethanesulfonyl) trifluoroacetamide, glycidyl Trimethylammonium (trifluoromethanesulfonyl) trifluoroacetamide, N, N-dimethyl-N-ethyl-N-pro Pyrammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-butylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-pentylammonium bis (trifluoromethane Sulfonyl) imide, N, N-dimethyl-N-ethyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N , N-dimethyl-N-ethyl-N-nonylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N, N-dipropylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N- Propi -N-butylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl-N-hexylammonium bis (Trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-butyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide N, N-dimethyl-N-butyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-pentyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, , N-dimethyl-N, N-dihexylammonium bis (trifluoromethanesulfonyl) imide, trimethylheptylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-propylammonium bis (trifluoromethanesulfonyl) Imido, N, N-diethyl-N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N- Diethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, triethylpropylammonium bis (trifluoromethanesulfonyl) imide, triethylpentylammonium bis (Trifluoromethanesulfonyl) imide, triethylheptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dipropyl-N-methyl-N-ethylammonium bis (trifluoromethanesulfonyl) imide, N, N-dipropyl-N-methyl- N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-dipropyl-N-butyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dipropyl-N, N-dihexylammonium bis (trifluoro) (Romethanesulfonyl) imide, N, N-dibutyl-N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-dibutyl-N-methyl-N-hexylammonium bis (g Fluoromethanesulfonyl) imide, trioctylmethylammonium bis (trifluoromethanesulfonyl) imide, N-methyl-N-ethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, 1-butyl-3methylpyridine- Examples thereof include 1-ium trifluoromethanesulfonate. As these commercially available products, for example, “CIL-314” (manufactured by Nippon Carlit Co., Ltd.), “ILA2-1” (manufactured by Koei Chemical Co., Ltd.) and the like can be used.
Also, for example, tetramethylammonium bis (trifluoromethanesulfonyl) imide, trimethylethylammonium bis (trifluoromethanesulfonyl) imide, trimethylbutylammonium bis (trifluoromethanesulfonyl) imide, trimethylpentylammonium bis (trifluoromethanesulfonyl) imide, trimethylheptyl Ammonium bis (trifluoromethanesulfonyl) imide, trimethyloctylammonium bis (trifluoromethanesulfonyl) imide, tetraethylammonium bis (trifluoromethanesulfonyl) imide, triethylbutylammonium bis (trifluoromethanesulfonyl) imide, tetrabutylammonium bis (trifluoromethanesulfonyl) Imide, tetrahex Le ammonium bis (trifluoromethanesulfonyl) imide, and the like.
Further, for example, 1-dimethylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-ethylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-propylpyrrolidinium bis (trifluoromethane) Sulfonyl) imide, 1-methyl-1-butylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-pentylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-hexylpyrrolidinium Bis (trifluoromethanesulfonyl) imide, 1-methyl-1-heptylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-propylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl- -Butyl pyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-pentylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-hexylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-heptylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1,1-dipropylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-propyl-1-butylpyrrolidinium bis (trifluoromethane) Sulfonyl) imide, 1,1-dibutylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-propylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-pentylpiperidinium bis (trifluoromethane) Sulfonyl) imide, 1,1-dimethylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-ethylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-propylpiperidinium bis ( Trifluoromethanesulfonyl) imide, 1-methyl-1-butylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-pentylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-hexylpi Peridinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-heptylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-propylpiperidinium bis (trifluoromethanesulfonyl) imide, 1- Ethyl-1-butylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-pentylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-hexylpiperidinium bis (trifluoromethanesulfonyl) Imido, 1-ethyl-1-heptylpiperidinium bis (trifluoromethanesulfonyl) imide, 1,1-dipropylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-propyl-1-butylpiperidinium bis (trifluoro) Lomethanesulfonyl) imide, 1,1-dibutylpiperidinium bis (trifluoromethanesulfonyl) imide, 1,1-dimethylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-ethylpyrrolidinium (Pentafluoroethanesulfonyl) imide, 1-methyl-1-propylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-butylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl -1-pentylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-hexylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-heptylpyrrolidinium bis (pentafluoro) Ethanesulfonyl) imide, 1-ethyl-1-propylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-butylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-pentyl Pyrrolidine Bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-hexylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-heptylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1, 1-dipropylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-propyl-1-butylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1,1-dibutylpyrrolidinium bis (pentafluoroethanesulfonyl) Imido, 1-propylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-pentylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1,1-dimethylpiperidinium bis (pentafluoroethanesulfonyl) i 1-methyl-1-ethylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-propylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-butylpiperidinium Bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-pentylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-hexylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl -1 heptylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-propylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-heptylpiperidinium bis (pentafluoroethane) Sulfonyl) imi , 1-ethyl-1-pentylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-hexylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-heptylpi Peridinium bis (pentafluoroethanesulfonyl) imide, 1-propyl-1-butylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1,1-dipropylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1, Examples include 1-dibutylpiperidinium bis (pentafluoroethanesulfonyl) imide.
Also, instead of the cation component of the above compound, trimethylsulfonium cation, triethylsulfonium cation, tributylsulfonium cation, trihexylsulfonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, dimethyldecylsulfonium cation, tetramethylphosphonium cation, tetraethylphosphonium Examples thereof include a compound using a cation, a tetrabutylphosphonium cation, and a tetrahexylphosphonium cation.
Further, instead of the above bis (trifluoromethanesulfonyl) imide, bis (pentafluorosulfonyl) imide, bis (heptafluoropropanesulfonyl) imide, bis (nonafluorobutanesulfonyl) imide, trifluoromethanesulfonyl nonafluorobutanesulfonylimide, And compounds using heptafluoropropanesulfonyl trifluoromethanesulfonylimide, pentafluoroethanesulfonylnonafluorobutanesulfonylimide, cyclo-hexafluoropropane-1,3-bis (sulfonyl) imide anion, and the like.

  Examples of the ionic compound include inorganic salts such as ammonium chloride, aluminum chloride, copper chloride, ferrous chloride, ferric chloride, and ammonium sulfate in addition to the alkali metal salts and organic cation-anion salts. . These ionic compounds can be used alone or in combination.

  As for the compounding quantity of the ionic compound in the adhesive composition of this invention, 0.05-10 weight part is preferable with respect to 100 weight part of (meth) acrylic-type polymers. If the ionic compound is less than 0.05 parts by weight, the effect of improving the antistatic performance may not be sufficient. The ionic compound is preferably 0.1 parts by weight or more, and more preferably 0.5 parts by weight or more. On the other hand, if the amount of the ionic compound is more than 10 parts by weight, the durability may not be sufficient. The ionic compound is preferably 5 parts by weight or less, more preferably 3 parts by weight or less, and further preferably 1 part by weight or less. The ratio of the ionic compound can be set within a preferable range by adopting the upper limit value or the lower limit value.

(7) Other additives The pressure-sensitive adhesive composition for a folding organic EL display device of the present invention may contain appropriate additives in addition to the above components, depending on the application. For example, tackifiers (for example, rosin derivative resins, polyterpene resins, petroleum resins, oil-soluble phenol resins, etc., solid, semi-solid, or liquid at room temperature); fillers such as hollow glass balloons; plasticizers; aging An antioxidant; a light stabilizer (HALS); and an antioxidant.

  In the present invention, the pressure-sensitive adhesive composition is preferably adjusted to have a viscosity suitable for work such as coating on a substrate. Adjustment of the viscosity of the pressure-sensitive adhesive composition is performed, for example, by adding various polymers such as thickening additives, polyfunctional monomers, or the like, or by partially polymerizing the monomer components in the pressure-sensitive adhesive composition. The partial polymerization may be performed before or after adding various polymers such as thickening additives, polyfunctional monomers, and the like. Since the viscosity of the pressure-sensitive adhesive composition varies depending on the amount of the additive and the like, the polymerization rate when the monomer component in the pressure-sensitive adhesive composition is partially polymerized cannot be uniquely determined, but as a guideline, it is about 20% or less. Preferably, it is about 3 to 20%, more preferably about 5 to 15%. If it exceeds 20%, the viscosity becomes too high, so that it is difficult to apply to the substrate.

2. Folding organic EL display device pressure-sensitive adhesive layer The folding organic EL display device pressure-sensitive adhesive layer of the present invention is formed from the above-mentioned folding organic EL display device pressure-sensitive adhesive composition.

  The method for forming the pressure-sensitive adhesive layer is not particularly limited, and can be formed by a method usually used in this field. Specifically, the pressure-sensitive adhesive composition is applied to at least one surface of the substrate, and a coating film formed from the pressure-sensitive adhesive composition is formed by drying, or irradiated with active energy rays such as ultraviolet rays. Can be formed.

  The substrate is not particularly limited. For example, various substrates such as a release film and a transparent resin film substrate, and a polarizing film described later can also be suitably used as the substrate.

  Examples of the constituent material of the release film include resin films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films, porous materials such as paper, cloth, and nonwoven fabric, nets, foam sheets, metal foils, and laminates thereof. Suitable thin leaf bodies and the like can be mentioned, but a resin film is suitably used from the viewpoint of excellent surface smoothness.

  Examples of the resin film include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, and ethylene. -A vinyl acetate copolymer film etc. are mentioned.

  The thickness of the release film is usually 5 to 200 μm, preferably about 5 to 100 μm. For the release film, if necessary, release agent and antifouling treatment with silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, silica powder, etc., coating type, kneading type, An antistatic treatment such as a vapor deposition type can also be performed. In particular, the release property from the pressure-sensitive adhesive layer can be further improved by appropriately performing a release treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment on the surface of the release film.

  The transparent resin film substrate is not particularly limited, and various resin films having transparency are used. The resin film is formed of a single layer film. For example, the materials include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, acetate resins, polyethersulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth) acrylic resins. , Polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl alcohol resin, polyarylate resin, polyphenylene sulfide resin, and the like. Of these, polyester resins, polyimide resins and polyethersulfone resins are particularly preferable.

  The thickness of the film substrate is preferably 15 to 200 μm, and more preferably 25 to 188 μm.

  The pressure-sensitive adhesive composition is applied onto the substrate by roll coating, kiss roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain. A known and appropriate method such as a coat, a lip coat, or a die coater can be used and is not particularly limited.

  When the pressure-sensitive adhesive layer is formed by drying a coating film formed from the pressure-sensitive adhesive composition, the drying conditions (temperature, time) are not particularly limited, and the composition of the pressure-sensitive adhesive composition, Although it can set suitably by a density | concentration etc., it is about 60-170 degreeC, for example, Preferably it is 60-150 degreeC, for 1 to 60 minutes, Preferably it is 2 to 30 minutes.

When the pressure-sensitive adhesive composition is an ultraviolet curable pressure-sensitive adhesive composition and is formed by irradiating a coating film formed from the ultraviolet-curable pressure-sensitive adhesive composition with ultraviolet rays, the illuminance of the irradiated ultraviolet rays is 5 mW / cm ² or more is preferable. When the illuminance of the ultraviolet light is less than 5 mW / cm ² , the polymerization reaction time becomes long and the productivity may be inferior. The illuminance of the ultraviolet light is preferably 200 mW / cm ² or less. When the illuminance of the ultraviolet rays exceeds 200 mW / cm ² , the photopolymerization initiator is consumed rapidly, so that the polymer has a low molecular weight, and the holding power particularly at high temperatures may be reduced. Further, the integrated quantity of ultraviolet light ^is preferably ^{100mJ / cm 2 ~5000mJ / cm 2} .

  The ultraviolet lamp used in the present invention is not particularly limited, but an LED lamp is preferable. Since the LED lamp has a lower emission heat than other ultraviolet lamps, the temperature during polymerization of the pressure-sensitive adhesive layer can be suppressed. Therefore, the molecular weight reduction of the polymer can be prevented, the cohesive strength of the pressure-sensitive adhesive layer can be prevented from being lowered, and the holding power at a high temperature when the pressure-sensitive adhesive sheet is used can be increased. It is also possible to combine a plurality of ultraviolet lamps. Further, it is possible to intermittently irradiate ultraviolet rays, and to provide a light period in which ultraviolet rays are irradiated and a dark period in which ultraviolet rays are not irradiated.

  In the present invention, the final polymerization rate of the monomer component in the ultraviolet curable pressure-sensitive adhesive composition is preferably 90% or more, more preferably 95% or more, and still more preferably 98% or more.

  In this invention, it is preferable that the peak wavelength of the ultraviolet-ray irradiated to the said ultraviolet curable adhesive composition exists in the range of 200-500 nm, and it is more preferable that it exists in the range of 300-450 nm. When the peak wavelength of ultraviolet rays exceeds 500 nm, the photopolymerization initiator may not be decomposed and the polymerization reaction may not start. On the other hand, if the peak wavelength of the ultraviolet light is less than 200 nm, the polymer chain may be cut and the adhesive properties may be deteriorated.

  Since the reaction is inhibited by oxygen in the air, a release film or the like is formed on the coating film formed from the ultraviolet curable acrylic pressure-sensitive adhesive composition to block oxygen, or the photopolymerization reaction is performed by nitrogen. It is preferable to carry out in an atmosphere. The above-mentioned thing can be mentioned as a release film. In addition, when a release film is used, the said release film can be used as a separator of a polarizing film with an adhesive layer as it is.

  Moreover, when the ultraviolet curable adhesive composition used by this invention contains a photoinitiator (B), the monomer component containing an alkyl (meth) acrylate and the said photoinitiator (B) ("Previous The composition including the “addition polymerization initiator” may be irradiated with ultraviolet rays to form a partial polymer of the monomer component, and the partial polymerization product of the monomer component may include an ultraviolet absorber, a dye compound, and a wavelength. It is preferable to add a photopolymerization initiator (A) having an absorption band at 400 nm or more (sometimes referred to as “post-addition polymerization initiator”) to prepare an ultraviolet curable pressure-sensitive adhesive composition. The polymerization rate of the partially polymerized product is preferably about 20% or less, more preferably about 3 to 20%, and still more preferably about 5 to 15%. The ultraviolet irradiation conditions are as described above.

  As described above, when the pressure-sensitive adhesive layer is formed from the ultraviolet curable pressure-sensitive adhesive composition containing the photopolymerization initiator (B), the polymerization rate of the monomer component is increased by polymerization in the two steps as described above. And the ultraviolet absorbing function of the finally produced pressure-sensitive adhesive layer can be improved.

  The thickness of the pressure-sensitive adhesive layer is preferably 5 μm or more, more preferably 10 μm or more, further preferably 15 μm or more, and particularly preferably 40 μm or more from the viewpoint of ensuring the function of absorbing light having a wavelength of less than 430 nm. Although the upper limit of the thickness of an adhesive layer is not specifically limited, It is preferable that it is 1 mm or less. When the thickness of the pressure-sensitive adhesive layer exceeds 1 mm, it becomes difficult to transmit ultraviolet rays, and it takes time to polymerize the monomer component, and causes problems in workability, winding in the process, and transportability, resulting in poor productivity. This is not preferable.

  The gel fraction of the pressure-sensitive adhesive layer of the present invention is not particularly limited, but is preferably 35% or more, more preferably 50% or more, and further preferably 75% or more, It is particularly preferably 85% or more. When the gel fraction of the pressure-sensitive adhesive layer is small, the cohesive force is inferior and there may be a problem in workability and handling properties.

As the surface resistance value of the pressure-sensitive adhesive layer of the present invention, a release film (separator) attached to protect the pressure-sensitive adhesive layer surface of the polarizing film with a pressure-sensitive adhesive layer for a folded organic EL display device described later is peeled off. Then, the surface resistance value on the pressure-sensitive adhesive layer surface can be measured and evaluated. The surface resistance value can be measured using a commercially available resistivity meter such as MCP-HT450 manufactured by Mitsubishi Chemical Analytech. The surface resistance value of the pressure-sensitive adhesive layer is preferably 1 × 10 ¹² Ω / □ or less, more preferably 5 × 10 ¹¹ Ω / □ or less, and further preferably 1 × 10 ¹¹ Ω / □. □ Below. If it is in the said range, the outstanding antistatic property can be provided, and it becomes a preferable aspect.

  The pressure-sensitive adhesive layer preferably has a haze value measured at a thickness of 25 μm of 2% or less, more preferably 0 to 1.5%, and still more preferably 0 to 1%. It is preferable that the haze is in the above range because the pressure-sensitive adhesive layer has high transparency.

  The average transmittance of the pressure-sensitive adhesive layer at a wavelength of 300 to 400 nm is preferably 5% or less, and more preferably 2% or less. Moreover, it is preferable that the average transmittance | permeability of wavelengths 400-430 nm or less is 30% or less, and it is more preferable that it is 20% or less. When the transmittance of the pressure-sensitive adhesive layer is within the above range, light in a region that does not affect the light emission of the organic EL element can be sufficiently absorbed, and deterioration of the organic EL element can be suppressed.

  The average transmittance of the pressure-sensitive adhesive layer at a wavelength of 450 to 500 nm is preferably 70% or more, more preferably 75% or more, and the average transmittance at a wavelength of 500 to 780 nm is preferably 80% or more. More preferably, it is 85% or more. When the transmittance of the pressure-sensitive adhesive layer is in the above range, light can be sufficiently transmitted in the light emitting region of the organic EL element (longer wavelength side than 430 nm), and an organic EL display using the pressure-sensitive adhesive layer. The device can emit enough light.

  Here, the “average transmittance at a wavelength of 300 to 400 nm” refers to an average value of the calculated transmittances obtained by calculating the transmittance at a 1 nm pitch in a wavelength range of 300 to 400 nm. The same applies to the average transmittance in other wavelength regions.

  The pressure-sensitive adhesive layer of the present invention has the above transmittance, so that it can sufficiently absorb light in a region that does not affect the light emission of the organic EL device, and the light emitting region of the organic EL device (wavelength longer than 430 nm). Side) can be sufficiently transmitted, and deterioration of the organic EL element due to external light can be suppressed.

  When the pressure-sensitive adhesive layer is exposed, the pressure-sensitive adhesive layer may be protected with a release film until practical use.

3. Polarizing film with pressure-sensitive adhesive layer for folding organic EL display device The polarizing film with a pressure-sensitive adhesive layer for folding organic EL display device of the present invention has a polarizing film and the pressure-sensitive adhesive layer for folding organic EL display device. It is characterized by.

  As the pressure-sensitive adhesive layer for the folding organic EL display device, those described above can be suitably used. When the pressure-sensitive adhesive layer is formed on a substrate other than the polarizing film, the pressure-sensitive adhesive layer can be attached to the polarizing film and transferred. Moreover, the said release film can be used as a separator of a polarizing film with an adhesive layer as it is, and can simplify in a process surface.

  The polarizing film is not particularly limited as long as it has a transparent protective film on at least one side of the polarizer and the polarizer, and has a transparent protective film on one side of the polarizer and the polarizer. And you may have a phase difference film on the other side.

(1) Polarizer The polarizer is not particularly limited, and various types can be used. Examples of polarizers include dichroic iodine and dichroic dyes on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films. Examples thereof include polyene-based oriented films such as those obtained by adsorbing substances and uniaxially stretched, polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products. Among these, a polarizer composed of a polyvinyl alcohol film and a dichroic substance 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 of potassium iodide or the like which may contain boric acid, zinc sulfate, zinc chloride or the like. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. In addition to washing the polyvinyl alcohol film surface with stains and antiblocking agents by washing the polyvinyl alcohol film with water, the polyvinyl alcohol film is also swollen to prevent unevenness such as uneven coloring. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. The film can be stretched even in an aqueous solution of boric acid or potassium iodide or in a water bath.

  In the present invention, a thin polarizer having a thickness of 10 μm or less can also be used. From the viewpoint of thinning, the thickness is preferably 1 to 7 μm. Such a thin polarizer is preferable in that the thickness unevenness is small, the visibility is excellent, the dimensional change is small, the durability is excellent, and the thickness of the polarizing film can be reduced.

  As the thin polarizer, typically, Japanese Patent Laid-Open No. 51-069644, Japanese Patent Laid-Open No. 2000-338329, International Publication No. 2010/100917, International Publication No. 2010/100917, or a patent. The thin polarizing film described in the specification of 4751481 and Unexamined-Japanese-Patent No. 2012-0753563 can be mentioned. These thin polarizing films can be obtained by a production method including a step of stretching and dyeing a polyvinyl alcohol-based resin (hereinafter also referred to as PVA-based resin) layer and a stretching resin substrate in the state of a laminate. With this production method, even if the PVA-based resin layer is thin, it can be stretched without problems such as breakage due to stretching by being supported by the stretching resin substrate.

  As the thin polarizing film, International Publication No. 2010/100917 pamphlet in that it can be stretched at a high magnification and the polarization performance can be improved among the production methods including the step of stretching in the state of a laminate and the step of dyeing. , WO 2010/100917 pamphlet, or patent 4751481 specification or JP 2012-073563 A is obtained by a manufacturing method including a step of stretching in a boric acid aqueous solution, particularly patents What is obtained by the manufacturing method including the process of extending | stretching in the air auxiliary before extending | stretching in the boric-acid aqueous solution which is described in the specification of 4751481 or Unexamined-Japanese-Patent No. 2012-073563 is preferable.

(2) Transparent protective film About a transparent protective film, what is used conventionally can be used suitably. Specifically, a transparent protective film formed from a material excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, and the like is preferable. For example, a polyester-based polymer such as polyethylene terephthalate or polyethylene naphthalate , Cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, styrene polymers such as polystyrene and acrylonitrile / styrene copolymer (AS resin), and polycarbonate polymers. 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 Examples of the polymer that forms the transparent protective film include polymer blends. 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.

  Although the thickness of a transparent protective film can be determined suitably, generally it is about 1-500 micrometers from points, such as workability | operativity, such as intensity | strength and handleability, and thin film property.

  The polarizer and the transparent protective film are preferably in close contact with each other via an ultraviolet curable adhesive. In addition to the above, examples of the adhesive between the polarizer and the transparent protective film include an aqueous adhesive and an electron beam curable adhesive. The electron beam curable polarizing film adhesive exhibits suitable adhesiveness with respect to the various viewing-side transparent protective films. 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 adhesive used in the present invention can contain a metal compound filler.

  The surface of the transparent protective film to which the polarizer is not adhered may be subjected to a treatment for the purpose of hard coat layer, antireflection treatment, sticking prevention, diffusion or antiglare.

  Moreover, as the transparent protective film, any one having a retardation and capable of functioning as an optical compensation layer can be used. When using the transparent protective film which has phase difference, the phase difference characteristic can be suitably adjusted to the value required for optical compensation. As such a retardation film, a stretched film can be suitably used. When the refractive index in the slow axis direction is nx, the in-plane fast axis direction refractive index is ny, and the thickness direction refractive index is nz, nx = ny> nz, nx> ny. > Nz, nx> ny = nz, nx> nz> ny, nz = nx> ny, nz> nx> ny, nz> nx = ny, satisfying the relationship of various types are selected and used. It is done. Note that nx = ny includes not only the case where nx and ny are completely the same, but also the case where nx and ny are substantially the same. Moreover, ny = nz includes not only the case where ny and nz are completely the same, but also the case where ny and nz are substantially the same.

  When the polarizing film used in the present invention is used as a circularly polarizing plate for preventing reflection of an organic EL display device, the retardation film has a front retardation of the transparent protective film of ¼ wavelength (about 100 to 170 nm). A quarter-wave plate is preferable.

  When using a retardation film as the transparent protective film, a film having a transparent protective film on one surface of the polarizer and a retardation film on the other surface can be suitably used. Further, in that case, the installation location of the pressure-sensitive adhesive layer is not particularly limited, and may be provided on the surface of the transparent protective film opposite to the surface in contact with the polarizer. However, from the viewpoint of suppressing deterioration of the organic EL display element, it is preferably provided on at least one surface or both surfaces.

  An example of a specific configuration of the polarizing film with a pressure-sensitive adhesive layer for a folding organic EL display device of the present invention is shown in FIGS. As shown in FIG. 1, adhesive layer 2 / transparent protective film 3 / polarizer 4 / retardation film 5, as shown in FIG. 2, transparent protective film 3 / polarizer 4 / retardation film 5 / adhesive layer 2. As shown in FIG. 3, the adhesive for organic EL display devices in which the layers are laminated in this order as adhesive layer 2 / transparent protective film 3 / polarizer 4 / retardation film 5 / adhesive layer 2; The polarizing film 1 with an agent layer can be mentioned. 1 and 2, the pressure-sensitive adhesive layer 2 is the pressure-sensitive adhesive layer for an organic EL display device of the present invention. In FIG. 3, at least one of the two pressure-sensitive adhesive layers 2 is the organic EL display of the present invention. What is necessary is just the adhesive layer for display apparatuses, and both may be the adhesive layer for organic EL display apparatuses of this invention. Moreover, in FIGS. 1-3, although the polarizing film 6 is a piece protection polarizing film comprised from the polarizer 4 and the transparent protective film 3, it is not limited to this, Polarizer 4 and phase difference Both protective polarizing films which have a transparent protective film further between the films 5 may be sufficient. As described above, various functional layers such as a hard coat layer can be formed on the surface of the transparent protective film 3 that is not in contact with the polarizer 4.

Moreover, when the said phase difference film is laminated | stacked on a polarizer through an adhesive layer, the said adhesive layer may be the adhesive layer for organic EL display apparatuses of this invention. That is, the polarizing film with an adhesive layer for an organic EL display device has a first adhesive layer, a transparent protective film, a polarizer, a second adhesive layer, a retardation film, and a third adhesive layer in this order.
Of the first pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer, and the third pressure-sensitive adhesive layer, at least one pressure-sensitive adhesive layer may be the pressure-sensitive adhesive layer for organic EL display devices.

  The polarizing film with a pressure-sensitive adhesive layer for a folding organic EL display device of the present invention may have an adhesive layer between the polarizing film and the pressure-sensitive adhesive layer for the folding organic EL display device. Examples of the adhesive layer include an anchor layer, and the material for forming the anchor layer is not particularly limited, and examples thereof include various polymers, metal oxide sols, and silica sols. Among these, polymers are particularly preferably used. The polymer may be used in any of a solvent-soluble type, a water-dispersed type, and a water-soluble type.

  Examples of the polymers include polyurethane resins, polyester resins, acrylic resins, polyether resins, cellulose resins, polyvinyl alcohol resins, polyvinyl pyrrolidone, polystyrene resins, and the like. Among these, polyurethane resins, polyester resins, and acrylic resins are particularly preferable. These resins can be appropriately mixed with a crosslinking agent. These other binder components can be used singly or in combination of two or more as appropriate.

  When the anchor layer is formed of a water dispersion type material, a water dispersion type polymer is used. Examples of the water-dispersible polymer include those obtained by emulsifying various resins such as polyurethane and polyester using an emulsifier, and introducing a water-dispersible anionic group, cationic group, or nonionic group into the resin. Examples include self-emulsified ones.

  The anchor agent can contain an antistatic agent. The antistatic agent is not particularly limited as long as it is a material that can impart conductivity, and examples thereof include ionic surfactants, conductive polymers, metal oxides, carbon black, and carbon nanomaterials. Among these, a conductive polymer is preferable, and a water-dispersible conductive polymer is more preferable.

  Examples of the water-soluble conductive polymer include polyaniline sulfonic acid (weight average molecular weight of 150,000 in terms of polystyrene, manufactured by Mitsubishi Rayon Co., Ltd.). TRON series).

  The blending amount of the antistatic agent is, for example, 70 parts by weight or less, preferably 50 parts by weight or less with respect to 100 parts by weight of the polymers used for the anchor agent. From the viewpoint of the antistatic effect, it is preferably 10 parts by weight or more, and more preferably 20 parts by weight or more.

  In addition, the anchor agent can be blended with various additives for the purpose of suppressing deterioration of the pressure-sensitive adhesive layer and the polarizer generated when contacting the anchor coat layer, and imparts a function to the anchor coat layer. Various additives can be blended for the purpose. For example, antioxidants, deterioration inhibitors, ultraviolet absorbers, fluorescent brighteners, and the like can be added.

  The thickness of the anchor layer is not particularly limited, but is preferably 5 to 300 nm.

  The method for forming the anchor layer is not particularly limited and can be performed by a generally known method. In forming the anchor layer, the polarizing film can be activated. Various methods can be employed for the activation treatment, such as corona treatment, low-pressure UV treatment, plasma treatment, and the like.

  The method for forming the pressure-sensitive adhesive layer on the anchor layer on the polarizing film is as described above.

  In addition, when the pressure-sensitive adhesive layer of the polarizing film with a pressure-sensitive adhesive layer for a folding organic EL display device of the present invention is exposed, the pressure-sensitive adhesive layer may be protected with a release film (separator) until practical use. Good. The above-mentioned thing can be mentioned as a release film. When a release film is used as a base material in the production of the above-mentioned pressure-sensitive adhesive layer, the release film is polarized with a pressure-sensitive adhesive layer by laminating the pressure-sensitive adhesive layer on the release film and the polarizing film. It can be used as a release film for the pressure-sensitive adhesive layer of the film, and the process can be simplified.

In the polarizing film with a pressure-sensitive adhesive layer for a folding organic EL display device of the present invention, the polarizing film preferably has a conductive layer between the pressure-sensitive adhesive layer for the folding organic EL display device. As the conductive layer (antistatic layer), for example, an antistatic composition containing a conductive polymer such as polythiophene and a binder is used, and the conductive layer (charged) is interposed between the polarizing film and the adhesive layer. A method of forming a prevention layer) can be employed. The surface resistance value of the conductive layer is preferably 1 × 10 ¹² or less.

4). Organic EL display device The organic EL display device of the present invention is characterized by using at least one pressure-sensitive adhesive layer for an organic EL display device of the present invention or the polarizing film with an adhesive layer for an organic EL display device of the present invention. And

  As an example of a specific configuration of the organic EL display device, for example, as shown in FIGS. 4 to 6, cover plastic (transparent substrate) 7 / adhesive layer 2 / transparent protective film 3 / polarizer 4 / position Phase difference film 5 / adhesive layer 2 / organic EL display panel (OLED element panel) 8 (FIG. 4); cover plastic (transparent substrate) 7 / adhesive layer 9 / transparent protective film 3 / polarizer 4 / retardation film 5 / adhesive layer 2 / organic EL display panel 8 (FIG. 5); cover plastic (transparent substrate) 7 / adhesive layer 2 / sensor layer 10 / adhesive layer 2 / transparent protective film 3 / polarizer 4 / position Examples thereof include an organic EL display device in which the respective layers are laminated in this order, such as phase difference film 5 / adhesive layer 2 / organic EL display panel 8 (FIG. 6). Of the pressure-sensitive adhesive layers 2 in each configuration, at least one pressure-sensitive adhesive layer of the present invention may be used, and all pressure-sensitive adhesive layers 2 may be pressure-sensitive adhesive layers of the present invention. In addition to the above, the organic EL display device of the present invention may include various functional layers such as a protective film and a hard coat layer. Moreover, in lamination | stacking of each layer, an adhesive layer and / or an adhesive layer can be used suitably. As the pressure-sensitive adhesive layer other than the pressure-sensitive adhesive layer of the present invention, a normal pressure-sensitive adhesive layer used in this field can be appropriately used.

  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]
[Polarizer]
As a thermoplastic resin substrate, an amorphous polyethylene terephthalate (hereinafter also referred to as “PET”) (IPA copolymerized PET) film (thickness: 100 μm) having 7 mol% of isophthalic acid units is prepared, and the surface is corona-treated ( 58 W / m ² / min). On the other hand, acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name: Gohsephimer Z200 (average polymerization degree: 1200, saponification degree: 98.5 mol%, acetoacetylation degree: 5 mol%)) Prepare 1 wt% PVA (polymerization degree 4200, saponification degree 99.2%), prepare PVA aqueous solution with 5.5 wt% PVA resin, and dry film thickness Was dried for 10 minutes by hot air drying in an atmosphere at 60 ° C. to prepare a laminate having a PVA resin layer on the substrate.

  Next, this laminate was first stretched 1.8 times in air at 130 ° C. (air-assisted stretching) to produce a stretched laminate. Next, a step of insolubilizing the PVA layer in which the PVA molecules contained in the stretched laminate were oriented was performed by immersing the stretched laminate in a boric acid insolubilized aqueous solution having a liquid temperature of 30 ° C. for 30 seconds. The boric acid insolubilized aqueous solution in this step had a boric acid content of 3 parts by weight with respect to 100 parts by weight of water. A colored laminate was produced by dyeing this stretched laminate. In the colored laminate, the single layer transmittance of the PVA layer constituting the finally produced polarizer is 40 to 44% in the dyed solution containing iodine and potassium iodide at a liquid temperature of 30 ° C. The PVA layer contained in the stretched laminate is dyed with iodine by immersing it in an arbitrary time. In this step, the staining solution was prepared using water as a solvent and an iodine concentration in the range of 0.1 to 0.4% by weight and a potassium iodide concentration in the range of 0.7 to 2.8% by weight. The concentration ratio of iodine and potassium iodide is 1 to 7. Next, the colored laminated body was immersed in a 30 ° C. boric acid crosslinking aqueous solution for 60 seconds to perform a crosslinking treatment between PVA molecules of the PVA layer on which iodine was adsorbed. The boric acid crosslinking aqueous solution in this step had a boric acid content of 3 parts by weight with respect to 100 parts by weight of water and a potassium iodide content of 3 parts by weight with respect to 100 parts by weight of water.

  Furthermore, the obtained colored laminate was stretched in a boric acid aqueous solution at a stretching temperature of 70 ° C. and stretched 3.05 times in the same direction as the stretching in the air (boric acid-water stretching), and finally An optical film laminate having a draw ratio of 5.50 was obtained. The optical film laminate was removed from the boric acid aqueous solution, and the boric acid adhering to the surface of the PVA layer was washed with an aqueous solution having a potassium iodide content of 4 parts by weight with respect to 100 parts by weight of water. The washed optical film laminate was dried by a drying process using hot air at 60 ° C. The thickness of the polarizer contained in the obtained optical film laminate was 5 μm.

[Transparent protective film]
As the transparent protective film, a methacrylic resin pellet having a glutarimide ring unit was extruded, formed into a film, and then stretched. This transparent protective film was an acrylic film having a thickness of 20 μm and a moisture permeability of 160 g / m ² .

  Subsequently, the said polarizer and the said transparent protective film were bonded together using the adhesive agent shown below, and it was set as the polarizing film.

As said adhesive (active energy ray hardening-type adhesive), each component is mixed according to the mixing | blending table | surface of Table 1, and it stirs at 50 degreeC for 1 hour, and adhesive (active energy ray hardening-type adhesive A) Was prepared. The numerical values in the table indicate% by weight when the total amount of the composition is 100% by weight. Each component used is as follows.
HEAA: hydroxyethyl acrylamide M-220: ARONIX M-220, tripropylene glycol diacrylate), manufactured by Toagosei Co., Ltd. ACMO: acryloylmorpholine AAEM: 2-acetoacetoxyethyl methacrylate, Nippon Synthetic Chemical Co., Ltd. UP-1190: ARUFUON UP- 1190, manufactured by Toagosei Co., Ltd. IRG907: IRGACURE907, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, manufactured by BASF DETX-S: KAYACURE DETX-S, diethylthioxanthone, Nippon Kayaku Made by Yakusha

In Examples and Comparative Examples using the adhesive, after laminating the transparent protective film and the polarizer via the adhesive, the adhesive was cured by irradiating ultraviolet rays, A layer was formed. For irradiation with ultraviolet rays, a gallium-filled metal halide lamp (Fusion UV Systems, Inc., trade name “Light HAMMER10”, bulb: V bulb, peak illuminance: 1600 mW / cm ² , integrated dose 1000 / mJ / cm ² (wavelength 380-440 nm)) was used.

[Example 1]
<Preparation of (meth) acrylic polymer>
A monomer mixture containing 99 parts by weight of butyl acrylate (BA) and 1 part by weight of 4-hydroxybutyl acrylate (HBA) was charged into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser. .
Furthermore, with respect to 100 parts by weight of the monomer mixture (solid content), 0.1 part by weight of 2,2′-azobisisobutyronitrile as a polymerization initiator was charged with ethyl acetate, and nitrogen gas was added while gently stirring. After introducing nitrogen and replacing with nitrogen, a polymerization reaction was carried out for 7 hours while maintaining the liquid temperature in the flask at around 55 ° C. Then, ethyl acetate was added to the resulting reaction solution to prepare a (meth) acrylic polymer solution having a weight average molecular weight (Mw) of 1.6 million adjusted to a solid content concentration of 30%.

<Preparation of acrylic pressure-sensitive adhesive composition>
0.1 parts by weight of an isocyanate-based crosslinking agent (trade name: Takenate D110N, trimethylolpropane xylylene diisocyanate, manufactured by Mitsui Chemicals, Inc.) with respect to 100 parts by weight of the solid content of the obtained (meth) acrylic polymer solution Benzoyl peroxide (trade name: Nyper BMT, manufactured by NOF Corporation) and a silane coupling agent (trade name: KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.08 part by weight, 2,4-bis-[{4- (4-ethylhexyloxy) -4-hydroxy} -phenyl] -6- (4-methoxyphenyl) -1,3 of the ultraviolet absorber (b1) , 5-triazine (trade name: Tinosorb S, absorption spectrum maximum absorption wavelength: 346 nm, manufactured by BASF Japan Ltd.) 2.5 parts by weight (solid content), ethyl acetate BONASORB UA3911 (trade name, indole compound, maximum absorption wavelength of absorption spectrum: 398 nm, half-value width: 48 nm, manufactured by Orient Chemical Co., Ltd.) 4 of a dye compound (c1) dissolved so as to have a form fraction of 5% An acrylic pressure-sensitive adhesive composition was obtained by adding and stirring parts by weight (solid content weight).

  The acrylic pressure-sensitive adhesive composition is uniformly coated with a fountain coater on the surface of a 38 μm thick polyethylene terephthalate film (PET film, transparent substrate) treated with a silicone release agent, and air circulation at 155 ° C. It dried for 2 minutes in the type | mold constant temperature oven, and formed the 25-micrometer-thick adhesive layer on the surface of a base material.

  Subsequently, the separator formed with the pressure-sensitive adhesive layer was transferred to the transparent protective film side (corona-treated) of the obtained polarizing film to prepare a laminate with the pressure-sensitive adhesive layer, and then the surface on which the separator was peeled off was corona. Bonded to a treated 25 μm PET film (transparent substrate, product name: Diafoil), a polarizing film with a pressure-sensitive adhesive layer for a folding organic EL display device was prepared (see FIG. 8). ).

[Example 2 and Comparative Example 1]
The adhesive for a folding organic EL display device is the same as in Example 1 except that the blending amounts of the ultraviolet absorber and the dye compound used in Example 1 are changed as shown in Table 2. A polarizing film with an agent layer was produced.

  The following evaluation was performed about the obtained (meth) acrylic-type polymer, the adhesive layer for bending type organic EL display apparatuses, and the polarizing film with an adhesive layer for bending type organic EL display apparatuses.

[Evaluation]
<Measurement of weight average molecular weight (Mw) of (meth) acrylic polymer>
The weight average molecular weight (Mw) 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 × 30cm each 90cm in total
-Column temperature: 40 ° C
・ Flow rate: 0.8ml / min
・ Injection volume: 100 μl
・ Eluent: Tetrahydrofuran ・ Detector: Differential refractometer (RI)
Standard sample: polystyrene

(Measurement of thickness)
The thicknesses of the polarizer, the transparent protective film, the pressure-sensitive adhesive layer and the like were measured using a dial gauge (manufactured by Mitutoyo) and obtained by calculation.

<Folding resistance test>
FIG. 7 shows a schematic diagram of a 180 ° folding resistance tester (manufactured by Imoto Seisakusho). This device has a mechanism in which a chuck on one side repeats 180 ° bending with a mandrel sandwiched in a thermostat, and the bending radius can be changed depending on the diameter of the mandrel. The test stops when the film breaks. In the test, the polarizing film with a pressure-sensitive adhesive layer of 5 cm × 15 cm obtained in each Example and Comparative Example (see FIG. 8) was set in an apparatus, and left at 60 ° C. × 95% RH for 24 hours. Furthermore, it was allowed to stand at a temperature of 25 ° C. × 24 hours, and evaluated under the conditions of 60 ° C. × 95% RH, a bending angle of 180 °, a bending radius of 3 mm, a bending speed of 1 second / time, and a weight of 100 g. Evaluation was performed after the number of times of folding reached 200,000 times for the following three evaluations.
In addition, as a sample for measurement (evaluation), the configuration shown in FIG. 8 is adopted, the polarizer is on the concave side (inside), and the transparent base material (PET film, cover plastic) is on the convex side (outside), near the center. It was bent and evaluated.

(Contamination resistance)
After reaching 200,000 times, bleeding out from the pressure-sensitive adhesive layer was visually confirmed and evaluated.
○: Level at which no particles are deposited in the pressure-sensitive adhesive layer when confirmed with a microscope. Δ: Level at which some particles are confirmed when confirmed with a microscope but are not visually confirmed. Particles are confirmed and there is a practical problem

(Folding strength)
After reaching 200,000 times, the presence or absence of breakage (peeling, etc.) was visually confirmed and evaluated.
○: Level at which no breakage / peeling is confirmed by visual inspection, or slight breakage / peeling is confirmed.
Δ: Slightly broken or peeled off at the end, but no problem in practical use.
X: A level where there is a problem in practical use because strong folds and peeling are confirmed visually.

(Appearance (color) evaluation)
After reaching 200,000 times, the color change was visually confirmed and evaluated.
○: No change compared to the initial stage.
Δ: Slight change, but practically no problem.
X: The color becomes transparent and has a practically problematic level (the dye compound is deteriorated).

Abbreviations in Table 2 are as follows.
b1: 2,4-bis-[{4- (4-ethylhexyloxy) -4-hydroxy} -phenyl] -6- (4-methoxyphenyl) -1,3,5-triazine (trade name: Tinosorb S, Absorption spectrum maximum absorption wavelength: 346 nm, manufactured by BASF Japan Ltd., UV absorber c1: BONASORB UA3911 (trade name, indole compound, absorption spectrum maximum absorption wavelength: 398 nm, half-value width: 48 nm, Orient Chemical Industry Co., Ltd.) Product), dye compounds

  From the results of Table 3 above, in the examples, by suppressing the total amount of the ultraviolet light inhibitor and the dye compound to a desired range, even when 200,000 times of folding resistance test was performed, the stain resistance, It was confirmed that the bending resistance was at a level having no practical problem. On the other hand, in Comparative Example 1, since the total amount exceeded the desired range, the ultraviolet ray-proofing agent bleeds out, inferior in stain resistance, peeled off, etc., and inferior in flex resistance. It was.

DESCRIPTION OF SYMBOLS 1 Polarizing film with an adhesive layer for folding type organic EL display devices 2 Adhesive layer (adhesive layer) for folding type organic EL display devices
3 Transparent protective film 4 Polarizer 5 Retardation film 6 Polarizing film 7 Cover plastic (transparent substrate)
8 Organic EL panel 9 Adhesive layer 10 Sensor layer

Claims (9)

A pressure-sensitive adhesive composition for a folding organic EL display device comprising, as a monomer component, a base polymer containing a monofunctional monomer, an ultraviolet absorber, and a dye compound having a maximum absorption wavelength of an absorption spectrum in the wavelength region of 380 to 430 nm A thing,
A pressure-sensitive adhesive composition for a folding organic EL display device comprising 0.1 to 15 parts by weight of the total amount of the ultraviolet absorber and the dye compound with respect to 100 parts by weight of the monofunctional monomer .   The pressure-sensitive adhesive composition for a folding organic EL display device according to claim 1, wherein the base polymer is a (meth) acrylic polymer.   The pressure-sensitive adhesive composition for a folding organic EL display device according to claim 1, comprising an ionic compound.   The pressure-sensitive adhesive composition for a folding organic EL display device according to any one of claims 1 to 3, further comprising a peroxide-based crosslinking agent.   A pressure-sensitive adhesive layer for a folding type organic EL display device, which is formed from the pressure-sensitive adhesive composition for a folding type organic EL display device according to any one of claims 1 to 4. 6. The pressure-sensitive adhesive layer for a folding organic EL display device according to claim 5, wherein the surface resistance value is 1 × 10 ¹² Ω / □ or less.   A polarizing film with a pressure-sensitive adhesive layer for a folding type organic EL display device, comprising a polarizing film and the pressure-sensitive adhesive layer for a folding type organic EL display device according to claim 5 or 6.   8. The polarizing film with a pressure-sensitive adhesive layer for a folding organic EL display device according to claim 7, further comprising a conductive layer between the polarizing film and the pressure-sensitive adhesive layer for the folding organic EL display device.   The pressure-sensitive adhesive layer for a folding organic EL display device according to claim 5 or 6 or the polarizing film with a pressure-sensitive adhesive layer for a folding organic EL display device according to claim 7 or 8 is used. A folding type organic EL display device.

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