JP2017120363A - Polarizing film with pressure-sensitive adhesive layer, and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polarizing film with a pressure-sensitive adhesive layer, which can solve a problem of decrease in a yield, can impart a sufficient function of blocking UV rays even when a polarizing film is thin, and can suppress curling, and to provide an image display device using the above polarizing film with a pressure-sensitive adhesive layer.SOLUTION: The polarizing film with a pressure-sensitive adhesive layer is to be used on a visible side of an image display part in an image display device; and the polarizing film with a pressure-sensitive adhesive layer includes a polarizing film and a pressure-sensitive adhesive layer on both surfaces of the polarizing film. The polarizing film includes a polarizer and a transparent protective film on both surfaces of the polarizer. The transparent protective film on a visible side of the polarizer has a transmittance of less than 6% at a wavelength of 380 nm; and the pressure-sensitive adhesive layer on a visible side of the polarizing film has an ultraviolet absorption function.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polarizing film with an adhesive layer used in an image display device. Moreover, this invention relates to the image display apparatus using the said polarizing film with an adhesive layer. Examples of the image display device include a liquid crystal display device, an organic EL (electroluminescence) display device, a PDP (plasma display panel), and electronic paper.

  In liquid crystal display devices and organic EL display devices, for example, in liquid crystal display devices, it is indispensable to dispose polarizing elements on both sides of the liquid crystal cell, and generally a polarizing film is attached. Has been. In addition to polarizing films, various optical elements have been used for display panels such as liquid crystal panels and organic EL panels in order to improve the display quality of displays.

  The polarizing film used in these image display devices generally has a configuration in which a polarizer is sandwiched between two protective films, and triacetyl cellulose (TAC) is widely used as the protective film.

  In recent years, with the trend of reducing the weight and thickness of image display devices, it has been required to reduce the thickness of each member used in the image display device, and also to reduce the thickness of the protective film of the polarizing film. When the thickness of the protective film is reduced, the ultraviolet light incident on the image display device cannot be sufficiently cut, and not only the polarizer but also various optical members such as liquid crystal panels and organic EL elements used in the image display device. There was a problem that the deterioration due to ultraviolet rays was accelerated.

  In order to solve such a problem, for example, a double-sided pressure-sensitive adhesive sheet for integrating two members disposed between the surface protection panel in the image display device and the viewing side of the liquid crystal module, Transparent double-sided pressure-sensitive adhesive for image display devices, having at least one ultraviolet absorbing layer, having a light transmittance of 380 nm or less and a visible light transmittance of 80% or more on a longer wavelength side than the wavelength of 430 nm A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer containing a sheet (for example, see Patent Document 1) or an acrylic polymer and a triazine-based ultraviolet absorber is known (for example, see Patent Document 2). Further, it is known that an ultraviolet absorbing ability can be imparted to the pressure-sensitive adhesive layer in a pressure-sensitive adhesive optical film in which a pressure-sensitive adhesive layer is provided on one or both sides of the optical film (see, for example, Patent Document 3).

JP 2012-211305 A JP 2013-75978 A Japanese Patent No. 4208187

  In recent years, as described in Patent Documents 1 to 3, it is known that various members used for an image display device are bonded using a transparent adhesive having an ultraviolet absorbing function. There were problems in terms of occurrence, yield deterioration, and workability.

  Depending on the application of the polarizing film, the polarizing film may be required to have a higher ultraviolet absorption function. Specifically, even when exposed to ultraviolet rays for a long time (specifically, about 300 hours) or when exposed to ultraviolet rays having a wide wavelength range, it is required that the optical characteristics do not change. Therefore, there has been a demand for a polarizing film that satisfies such a higher ultraviolet absorption function.

  Moreover, there also existed a problem that curl would arise in the polarizing film obtained by making the polarizer and protective film of a polarizing film into a thin film.

  Therefore, the present invention can solve the problem of yield reduction, and even when the polarizing film is thin, can provide a higher UV cut function and can suppress the occurrence of curling. It aims at providing the polarizing film with an adhesive layer. Another object of the present invention is to provide an image display device using 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 polarizing film with a pressure-sensitive adhesive layer and completed the present invention.

That is, the present invention is a polarizing film with a pressure-sensitive adhesive layer used on the viewing side from the image display unit in the image display device,
The polarizing film with the pressure-sensitive adhesive layer has a pressure-sensitive adhesive layer on both sides of the polarizing film and the polarizing film,
The polarizing film has a transparent protective film on both sides of the polarizer and the polarizer,
Polarized light with pressure-sensitive adhesive layer, wherein the transparent protective film on the viewing side of the polarizer has a transmittance at a wavelength of 380 nm of less than 6%, and the pressure-sensitive adhesive layer on the viewing side of the polarizing film has an ultraviolet absorbing function Related to film.

  The transparent protective film on the viewer side of the polarizer is at least one film selected from the group consisting of a triacetyl cellulose film, an acrylic film, a polyethylene terephthalate film, and a polyolefin film having a cyclo or norbornene structure, and The thickness is preferably 40 μm or less.

  It is preferable that the thickness of the pressure-sensitive adhesive layer on the viewing side of the polarizing film is twice or more the thickness of the pressure-sensitive adhesive layer on the image display unit side of the polarizing film.

  The adhesive layer on the viewing side of the polarizing film preferably has a transmittance at a wavelength of 380 nm of 9% or less and a transmittance at a wavelength of 400 nm of 60% or more.

  It is preferable that b * value of the adhesive layer by the side of visual recognition of the said polarizing film is 3.0 or less.

  The pressure-sensitive adhesive layer on the viewing side of the polarizing film preferably has a transmittance at a wavelength of 380 nm of 9% or less and a transmittance at a wavelength of 420 nm of 75% or less.

  It is preferable that the pressure-sensitive adhesive layer on the viewing side of the polarizing film contains an acrylic polymer as a base polymer.

  The polarizing film with an adhesive layer of the present invention is preferably used for a liquid crystal display device or an organic EL display device.

  Moreover, this invention relates to the image display apparatus characterized by using the polarizing film with an adhesive layer of this invention for the visual recognition side from the image display part.

  Since the polarizing film with the pressure-sensitive adhesive layer of the present invention has a configuration in which the pressure-sensitive adhesive layer having an ultraviolet absorbing function is laminated in advance on the viewing side of the polarizing film, the problem of process deletion and yield reduction can be solved. And even if it is a case where a polarizing film is thin, a higher ultraviolet cut function can be provided and curling generation | occurrence | production can be suppressed. Moreover, since the image display apparatus of this invention uses the said polarizing film with an adhesive layer, it suppresses the deterioration by ultraviolet rays of various optical members used for an image display apparatus, such as a liquid crystal panel and an organic EL element. be able to.

It is sectional drawing which shows typically one Embodiment of the polarizing film with an adhesive layer of this invention. It is sectional drawing which shows typically one Embodiment of the image display apparatus of this invention. It is sectional drawing which shows typically one Embodiment of the image display apparatus of this invention. It is sectional drawing which shows typically one Embodiment of the image display apparatus of this invention.

1. The polarizing film with the pressure-sensitive adhesive layer The polarizing film with the pressure-sensitive adhesive layer of the present invention is used on the viewing side from the image display unit in the image display device,
The polarizing film with the pressure-sensitive adhesive layer has a pressure-sensitive adhesive layer on both sides of the polarizing film and the polarizing film,
The polarizing film has a transparent protective film on both sides of the polarizer and the polarizer,
The transmittance of the transparent protective film on the viewing side of the polarizer at a wavelength of 380 nm is less than 6%, and the adhesive layer on the viewing side of the polarizing film has an ultraviolet absorbing function.

  As shown in FIG. 1, the polarizing film 1 with the pressure-sensitive adhesive layer of the present invention has a viewing-side pressure-sensitive adhesive layer 2 a / viewing-side transparent protective film 3 a / polarizer 4 / image display unit side transparent protective film 3 b / image display unit side. Any structure including the pressure-sensitive adhesive layer 2b may be used, and a structure including a retardation film or the like may be used. Specifically, viewing side adhesive layer 2a / viewing side transparent protective film 3a / polarizer 4 / image display unit side transparent protective film 3b / image display unit side adhesive layer 2b / retardation film (not shown) / image A structure such as a display unit side pressure-sensitive adhesive layer (not shown) may be used. The polarizing film 5 includes a viewing-side transparent protective film 3a / a polarizer 4 / an image display unit-side transparent protective film 3b. Each layer will be described in detail below.

(1) Viewing-side pressure-sensitive adhesive layer In the present invention, the viewing-side pressure-sensitive adhesive layer (viewing-side pressure-sensitive adhesive layer) of the polarizing film has an ultraviolet absorbing function. The visible-side pressure-sensitive adhesive layer only needs to have an ultraviolet absorbing function, and the composition thereof is not particularly limited.

  An appropriate pressure-sensitive adhesive can be used for the formation of the viewing-side pressure-sensitive adhesive layer, and the type thereof is not particularly limited. Adhesives include rubber adhesives, acrylic adhesives, silicone adhesives, urethane adhesives, vinyl alkyl ether adhesives, polyvinyl alcohol adhesives, polyvinyl pyrrolidone adhesives, polyacrylamide adhesives, Examples thereof include cellulose-based pressure-sensitive 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. . The acrylic pressure-sensitive adhesive (composition) contains an acrylic polymer as a base polymer.

  The acrylic pressure-sensitive adhesive composition preferably contains, 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 and an ultraviolet absorber. .

(1-1) Partial polymer of monomer component and (meth) acrylic polymer The acrylic pressure-sensitive adhesive composition is obtained from a partial polymer of a monomer component containing alkyl (meth) acrylate and / or the monomer component. (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.

  As said alkyl (meth) acrylate, the alkyl (meth) acrylate which has the said C1-C9 branch can be illustrated preferably, for example. The alkyl (meth) acrylate is preferable in terms of easily balancing the adhesive properties. 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, isononyl (meth) acrylate, and the like are used, and these are used alone or in combination of two or more. be able to.

  In the present invention, the alkyl (meth) acrylate having an alkyl group having 1 to 24 carbon atoms at the ester terminal is 40% by weight or more based on the total amount of the monofunctional monomer component forming the (meth) acrylic polymer. It is preferably 50% by weight or more, more 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 polyfunctional monomer is a monomer having at least two polymerizable functional groups having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group, such as (poly) ethylene glycol di (meth) acrylate, (Poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,2-ethylene Glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate Ester compounds of polyhydric alcohols such as (meth) acrylic acid; allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyl di (meth) acrylate, hexyl di (meth) ) Acrylate and the like. Among these, trimethylolpropane tri (meth) acrylate, hexanediol di (meth) acrylate, and dipentaerythritol hexa (meth) acrylate can be preferably used. A polyfunctional monomer can be used individually by 1 type or in combination of 2 or more types.

  The amount of the polyfunctional monomer used varies depending on the molecular weight, the number of functional groups, etc., but it is preferably used at 3 parts by weight or less, more preferably 2 parts by weight or less, with respect to 100 parts by weight of the monofunctional monomer in total. 1 part by weight or less is more preferable. Moreover, it does not specifically limit as a lower limit, However It is preferable that it is 0 weight part or more, and it is more preferable that it is 0.001 weight part or more. Adhesive force can be improved when the usage-amount of a polyfunctional monomer exists in the said range.

  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.

  Moreover, when manufacturing the said (meth) acrylic-type polymer by radiation polymerization, it can superpose | polymerize and manufacture by irradiating radiation, such as an electron beam and an ultraviolet-ray (UV), to the said monomer component. Among these, ultraviolet polymerization is preferable. Hereinafter, ultraviolet polymerization which is a preferable embodiment in radiation polymerization will be described.

  When performing the ultraviolet polymerization, it is preferable to contain a photopolymerization initiator in the monomer component because of the advantage that the polymerization time can be shortened. Therefore, when performing ultraviolet polymerization, for example, an ultraviolet curable acrylic pressure-sensitive adhesive containing a monomer component containing the alkyl (meth) acrylate and / or a partial polymer of the monomer component, an ultraviolet absorber, and a photopolymerization initiator. It is preferably formed by ultraviolet polymerization of the composition. Since the pressure-sensitive adhesive layer formed by ultraviolet polymerization of the ultraviolet curable acrylic pressure-sensitive adhesive composition can be formed to have a thickness of 150 μm or more, and a pressure-sensitive adhesive layer having a wide thickness can be formed. preferable.

  The photopolymerization initiator preferably contains a photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or longer. When the ultraviolet light absorber was included in the pressure-sensitive adhesive composition, the ultraviolet light was absorbed by the ultraviolet light absorber and was not sufficiently polymerized. However, the photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more is preferable because it can be sufficiently polymerized even though it contains an ultraviolet absorber.

  As a photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (Irgacure 819, manufactured by BASF), 2,4,6-trimethylbenzoyl- And diphenyl-phosphine oxide (LUCIRIN TPO, manufactured by BASF).

  The photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more may be used alone or in combination of two or more.

  Further, the addition amount of the photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more is not particularly limited, but is preferably smaller than the addition amount of an ultraviolet absorber described later, (meta) The amount is preferably about 0.005 to 1 part by weight and more preferably about 0.02 to 0.5 part by weight with respect to 100 parts by weight of the monofunctional monomer component forming the acrylic polymer. It is preferable that the amount of the photopolymerization initiator (A) added is in the above range because ultraviolet polymerization can sufficiently proceed.

  The photopolymerization initiator may contain a photopolymerization initiator (B) having an absorption band at a wavelength of less than 400 nm. Moreover, it is preferable that a photoinitiator (B) does not have an absorption band in wavelength 400nm or more. The photopolymerization initiator (B) is not particularly limited as long as it generates radicals by ultraviolet rays and starts photopolymerization and has an absorption band at a wavelength of less than 400 nm. Any initiator can be suitably used. For example, benzoin ether photopolymerization initiator, acetophenone photopolymerization initiator, α-ketol photopolymerization initiator, photoactive oxime photopolymerization initiator, benzoin photopolymerization initiator, benzyl photopolymerization initiator, benzophenone A photopolymerization initiator, a ketal photopolymerization initiator, a thioxanthone photopolymerization initiator, an acylphosphine oxide photopolymerization initiator, or the like can be used.

  Specifically, examples of the benzoin ether photopolymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane- Examples include 1-one and anisole methyl ether.

  Examples of the acetophenone photopolymerization initiator include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 4-phenoxydichloroacetophenone, and 4-t-butyldichloroacetophenone. Etc.

  Examples of the α-ketol photopolymerization initiator include 2-methyl-2-hydroxypropiophenone, 1- [4- (2-hydroxyethyl) phenyl] -2-hydroxy-2-methylpropan-1-one, and the like. Is mentioned.

  Examples of the photoactive oxime photopolymerization initiator include 1-phenyl-1,2-propanedione-2- (O-ethoxycarbonyl) -oxime.

  Examples of the benzoin photopolymerization initiator include benzoin.

  Examples of the benzyl photopolymerization initiator include benzyl.

  Examples of the benzophenone photopolymerization initiator include benzophenone, benzoylbenzoic acid, 3,3′-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexyl phenyl ketone, and the like.

  Examples of the ketal photopolymerization initiator include benzyl dimethyl ketal.

  Examples of the thioxanthone photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4. -Diisopropylthioxanthone, dodecylthioxanthone and the like are included.

  Examples of the acylphosphine oxide-based photopolymerization initiator include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, and the like.

  The photopolymerization initiator (B) having an absorption band at a wavelength of less than 400 nm can be used alone or in combination of two or more. The photopolymerization initiator (B) having an absorption band at a wavelength of less than 400 nm can be added within a range that does not impair the effects of the present invention, and the addition amount is a monofunctional that forms a (meth) acrylic polymer. The amount is preferably about 0.005 to 0.5 parts by weight and more preferably about 0.02 to 0.1 parts by weight with respect to 100 parts by weight of the monomeric monomer component.

  In the present invention, when the monomer component is subjected to ultraviolet polymerization, a photopolymerization initiator (B) having an absorption band at a wavelength of less than 400 nm is first added to the monomer component, and ultraviolet rays are irradiated to partially polymerize. It is preferable to perform ultraviolet polymerization by adding a photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more and an ultraviolet absorber to a partial polymerization product (prepolymer composition) of a monomer component. When the photopolymerization initiator (A) having an absorption band at a wavelength of 400 nm or more is added to the partial polymerization product (prepolymer composition) of the monomer component partially polymerized by ultraviolet irradiation, the photopolymerization is started. It is preferable to add the agent after dissolving it in the monomer.

(1-2) Ultraviolet absorber The ultraviolet absorber contained in the acrylic pressure-sensitive adhesive composition is not particularly limited. For example, a triazine ultraviolet absorber, a benzotriazole ultraviolet absorber, a benzophenone ultraviolet absorber, An oxybenzophenone type ultraviolet absorber, a salicylic acid ester type ultraviolet 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 compound of 3- (2H-benzotriazol-2-yl) -5- (1,1-dimethylethyl) -4-hydroxy (C7-9 side chain and straight chain alkyl) (TINUVIN 384-2, BASF) 2-, (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-fe) Nylethyl) 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 Chloro (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 ( TINUVIN571, 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-based ultraviolet absorber (salicylic acid ester-based compound) include phenyl-2-acryloyloxybenzoate, phenyl-2-acryloyloxy-3-methylbenzoate, and phenyl-2-acryloyloxy. -4-methylbenzoate, phenyl-2-acryloyloxy-5-methylbenzoate, phenyl-2-acryloyloxy-3-methoxybenzoate, phenyl-2-hydroxybenzoate, phenyl-2-hydroxy -3-methylbenzoate, phenyl-2-hydroxy-4 methylbenzoate, phenyl-2-hydroxy-5-methylbenzoate, phenyl 2-hydroxy-3-methoxybenzoate, 2,4-di-tert -Butylphenyl-3,5-di-tert-butyl And the like-4-hydroxybenzoate (TINUVIN120, manufactured by BASF).

  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.

  Moreover, as a ultraviolet absorber, a brand name "FDB-001" (made by Yamada Chemical Industry Co., Ltd.), a brand name "SMP-122" (made by Hayashibara Co., Ltd.), an azomethine compound (brand name: BONASORB UA-), for example. 3911, manufactured by Orient Chemical Industry Co., Ltd.), indole chemicals (trade name: BONASORB UA-3701, manufactured by Orient Chemical Industry Co., Ltd.), Disperse Yellow 54 (trade name: KAYASET YELLOW AG, manufactured by Nippon Kayaku Co., Ltd.) , Quinophthalone compound (trade name: MS YELLOW HD-137, manufactured by Yamada Chemical Co., Ltd.), Solvent Yellow91 (PLASTYELLOW 8000, manufactured by Arimoto Chemical Co., Ltd.), Solvent Yellow 163 (KP Plastic Yellow MK, Kiwa Chemical Industries) Made by Co., Ltd.) It can also be used in the dye.

  The ultraviolet absorber may be used alone or in combination of two or more, but the total content is a monofunctional monomer component that forms a (meth) acrylic polymer. The amount is preferably about 0.1 to 5 parts by weight and more preferably about 0.5 to 3 parts by weight with respect to 100 parts by weight. By making the addition amount of the ultraviolet absorber within the above range, it is preferable that the ultraviolet ray absorbing function of the pressure-sensitive adhesive layer can be sufficiently exhibited, and when the ultraviolet polymerization is performed, the polymerization is not hindered.

(1-3) Silane Coupling Agent Furthermore, the acrylic pressure-sensitive adhesive composition used in the present invention can 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 0.02 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.

(1-4) Crosslinking agent The acrylic adhesive composition used by this invention can contain a crosslinking agent. Examples of crosslinking agents include isocyanate crosslinking agents, epoxy crosslinking agents, silicone crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, silane crosslinking agents, alkyletherified melamine crosslinking agents, metal chelate crosslinking agents, Crosslinkers such as oxides are included. A crosslinking agent can be used alone or in combination of two or more. Among these, an isocyanate type crosslinking agent is preferably used.

  The crosslinking agent may be used alone or in combination of two or more, but the total content is a monofunctional monomer that forms a (meth) acrylic polymer. It is preferably 5 parts by weight or less, more preferably 0.01 to 5 parts by weight, further preferably 0.01 to 4 parts by weight, and 0.02 to 3 parts by weight with respect to 100 parts by weight of the component. It is preferable to obtain.

  The isocyanate-based crosslinking agent refers to a compound having two or more isocyanate groups (including isocyanate-regenerating functional groups in which isocyanate groups are temporarily protected by a blocking agent or quantification) in one molecule. Examples of the isocyanate-based crosslinking agent include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate, alicyclic isocyanates such as isophorone diisocyanate, and aliphatic isocyanates such as hexamethylene diisocyanate.

  More specifically, for example, lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, cycloaliphatic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate, 2,4-tolylene diisocyanate, Aromatic diisocyanates such as 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate, polymethylene polyphenyl isocyanate, trimethylolpropane / tolylene diisocyanate trimer adduct (trade name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.) ), Trimethylolpropane / hexamethylene diisocyanate trimer adduct (trade name: Coronate HL, manufactured by Nippon Polyurethane Industry Co., Ltd.), hexamethylene Isocyanurate of isocyanate (trade name: Coronate HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) and the like, trimethylolpropane adduct of xylylene diisocyanate (trade name: D110N, manufactured by Mitsui Chemicals, Inc.), hexa Trimethylolpropane adduct of methylene diisocyanate (trade name: D160N, manufactured by Mitsui Chemicals); polyether polyisocyanate, polyester polyisocyanate, and adducts of these with various polyols, isocyanurate bond, burette bond, Examples thereof include polyisocyanates polyfunctionalized with allophanate bonds.

(1-5) Other additives The acrylic pressure-sensitive adhesive composition used in 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 Inhibitors; antioxidants and the like.

(1-6) Formation method of visual recognition side adhesive layer In this invention, it is preferable to adjust the said acrylic adhesive composition to the viscosity suitable for the operation | work etc. which apply | coat etc. on a base material. Adjustment of the viscosity of the acrylic 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 monomer components in the acrylic 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 acrylic pressure-sensitive adhesive composition varies depending on the amount of the additive and the like, the polymerization rate when the monomer component in the acrylic pressure-sensitive adhesive composition is partially polymerized cannot be uniquely determined. It is preferably about 20% or less, more preferably about 3 to 20%, and still 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.

  The viewing-side pressure-sensitive adhesive layer is formed by coating the acrylic pressure-sensitive adhesive composition on at least one side of the substrate and drying the coating film formed from the acrylic pressure-sensitive adhesive composition, or by ultraviolet rays or the like It can be formed by irradiation with active energy rays.

  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. When the viewing-side pressure-sensitive adhesive layer is formed on a substrate other than the polarizing film, the viewing-side pressure-sensitive adhesive layer can be attached to the polarizing film and transferred.

  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 method for applying the acrylic pressure-sensitive adhesive composition onto the substrate is roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat. Any known appropriate method such as curtain coating, lip coating, or die coater can be used without particular limitation.

  When the visible-side pressure-sensitive adhesive layer is formed by drying a coating film formed from the acrylic pressure-sensitive adhesive composition, the drying conditions (temperature, time) are not particularly limited, and the pressure-sensitive adhesive composition Although it can set suitably by a composition, 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 acrylic pressure-sensitive adhesive composition is an ultraviolet curable acrylic pressure-sensitive adhesive composition and is formed by irradiating a coating film formed from the ultraviolet-curable acrylic pressure-sensitive adhesive composition with ultraviolet rays, the ultraviolet rays to be irradiated The illuminance is preferably 5 mW / cm ² or more. 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 acrylic 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 acrylic 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 acrylic adhesive composition used by this invention contains a photoinitiator (B), the monomer component containing an alkyl (meth) acrylate and the said photoinitiator (B) ( The composition containing the “pre-added polymerization initiator” is irradiated with ultraviolet rays to form a partial polymer of the monomer component, and the partial polymerization product of the monomer component contains an ultraviolet absorber and a wavelength of 400 nm. It is preferable to prepare a UV-curable acrylic pressure-sensitive adhesive composition by adding the photopolymerization initiator (A) having an absorption band (sometimes referred to as “post-addition polymerization initiator”). 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 acrylic pressure-sensitive adhesive composition containing the photopolymerization initiator (B), the polymerization rate of the monomer component is increased by performing polymerization in the two steps as described above. In addition, the ultraviolet absorbing function of the finally produced pressure-sensitive adhesive layer can be improved.

  The thickness of the visual recognition side pressure-sensitive adhesive layer is at least twice the thickness of the pressure-sensitive adhesive layer (image display part-side pressure-sensitive adhesive layer) on the image display part side of the polarizing film described later from the viewpoint of ensuring the ultraviolet absorption function. Preferably, it is 5 times or more, more preferably 10 times or more. Specifically, the thickness of the viewing-side pressure-sensitive adhesive layer is preferably 50 μm or more, more preferably 100 μm or more, and further preferably 150 μm or more. Although the upper limit of the thickness of a visual recognition side adhesive layer is not specifically limited, It is preferable that it is 10 mm or less. If the thickness of the pressure-sensitive adhesive layer exceeds 10 mm, it is difficult to transmit ultraviolet rays, and it takes time to polymerize the monomer component, which may be inferior in productivity.

  Although the gel fraction of the visual recognition side adhesive layer of this invention is not specifically limited, It is preferable that it is 35% or more, It is more preferable that it is 50% or more, It is further that it is 75% or more It is preferably 85% or more. When the gel fraction of the visible-side pressure-sensitive adhesive layer is small, the cohesive force is inferior, and when it is too large, the adhesive force may be inferior.

  The permeation b * value of the viewing side pressure-sensitive adhesive layer is not particularly limited, but is preferably 3.0 or less, more preferably 1.5 or less, and even more preferably 0.5 or less. The b * value refers to the b * value (chromaticity) in the L * a * b * color system according to JIS Z8729. For example, a spectrophotometer (product name: U4100, manufactured by Hitachi High-Technologies Corporation) ).

  The transmittance of the viewing side pressure-sensitive adhesive layer at a wavelength of 380 nm is preferably 9% or less, more preferably 7% or less, further preferably 5% or less, and more preferably 3% or less. Particularly preferred. Since the transmittance at a wavelength of 380 nm is within the above range, incident ultraviolet rays can be blocked to a higher degree, so that deterioration of optical members such as liquid crystal panels, organic EL elements, polarizers, etc. is remarkably suppressed. Can do.

  The transmittance of the viewing side pressure-sensitive adhesive layer at a wavelength of 400 nm is preferably 60% or more, preferably 70% or more, and more preferably 75% or more. When the transmittance at a wavelength of 400 nm is within the above range, it is preferable because the incident visible light can be sufficiently transmitted and sufficient visibility can be secured in the image display device.

  Moreover, when using the polarizing film with an adhesive layer of this invention for an organic electroluminescence display (OLED), it is preferable that the transmittance | permeability in wavelength 420nm of the said visual recognition side adhesive layer is 75% or less, and is 50% or less. More preferably, it is more preferably 40% or less. The transmittance at a wavelength of 420 nm is in the above range, which is preferable from the viewpoint of protecting the light emitting element of the OLED.

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

(2) Image display part side adhesive layer It does not specifically limit as an adhesive layer (image display part side adhesive layer) of the image display part side surface of a polarizing film, It is detailed in the said visual recognition side adhesive layer. The same acrylic adhesive composition as described above may be used, and various adhesive layers that are usually used can be used.

  An appropriate pressure-sensitive adhesive can be used for forming the pressure-sensitive adhesive layer on the surface of the image display unit, and the type thereof is not particularly limited. Adhesives include rubber adhesives, acrylic adhesives, silicone adhesives, urethane adhesives, vinyl alkyl ether adhesives, polyvinyl alcohol adhesives, polyvinyl pyrrolidone adhesives, polyacrylamide adhesives, Examples thereof include cellulose-based pressure-sensitive 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. .

  The acrylic pressure-sensitive adhesive is based on an acrylic polymer having a monomer unit of (meth) acrylic acid alkyl ester as a main skeleton. Examples of the (meth) acrylic acid alkyl ester constituting the main skeleton of the acrylic polymer may include the same ones as those used for the acrylic pressure-sensitive adhesive composition forming the viewing-side pressure-sensitive adhesive layer. Moreover, the same thing as what is used for the said acrylic adhesive composition can also be mentioned as a copolymerization monomer and its ratio.

  The acrylic polymer can be produced by various known methods. For example, a radical polymerization method such as a bulk polymerization method, a solution polymerization method, or a suspension polymerization method can be appropriately selected. As the radical polymerization initiator, various known azo and peroxide initiators can be used. The reaction temperature is usually about 50 to 80 ° C., and the reaction time is 1 to 8 hours. Among the above production methods, the solution polymerization method is preferable, and ethyl acetate, toluene and the like are generally used as the solvent for the acrylic polymer. The solution concentration is usually about 20 to 80% by weight.

  Moreover, the said adhesive can be made into the adhesive composition containing a crosslinking agent. Although the above-mentioned thing can also be mentioned as a crosslinking agent, Especially an isocyanate type crosslinking agent is preferable. The blending ratio of the acrylic polymer and the crosslinking agent is not particularly limited, but usually it is preferably about 0.001 to 20 parts by weight of the crosslinking agent (solid content) with respect to 100 parts by weight of the acrylic polymer (solid content). About 0.01 to 15 parts by weight is more preferable.

  Furthermore, the pressure-sensitive adhesive may include a tackifier, a plasticizer, glass fiber, glass beads, metal powder, other inorganic powders, a pigment, a colorant, a filler, an antioxidant, if necessary. Various additives may be used as appropriate, such as an agent, an ultraviolet absorber, a silane coupling agent, and the like without departing from the object of the present invention. Moreover, it is good also as an adhesive layer etc. which contain microparticles | fine-particles and show light diffusibility. Examples of the silane coupling agent include those described above.

  An image display part side adhesive layer is formed by apply | coating the said adhesive composition to various base materials, such as a polarizing film or a release film, and drying. When the pressure-sensitive adhesive layer is formed on various substrates such as a release film, the pressure-sensitive adhesive layer can be attached to a polarizing film and transferred. Examples of the method for applying the pressure-sensitive adhesive and the various base materials include the same methods as those for applying the acrylic pressure-sensitive adhesive composition and various base materials.

  Moreover, in the said application | coating process, the application quantity is controlled so that the adhesive layer formed may become predetermined | prescribed thickness (thickness after drying). The thickness of the image display unit side pressure-sensitive adhesive layer is not particularly limited, but is preferably 1/2 or less, more preferably 1/5 or less of the thickness of the visual recognition side pressure-sensitive adhesive layer. / 10 or less is preferable. Specifically, the thickness of the image display unit side pressure-sensitive adhesive layer is preferably about 1 to 100 μm, more preferably about 3 to 50 μm, and still more preferably about 5 to 30 μm.

  In forming the image display unit side pressure-sensitive adhesive layer, the applied pressure-sensitive adhesive is dried. The drying temperature and drying time are not particularly limited and are appropriately set. For example, the drying temperature and the drying time are about 80 to 200 ° C. and preferably 0.5 to 10 minutes.

  When the image display unit side pressure-sensitive adhesive layer is exposed, the pressure-sensitive adhesive layer may be protected with a release film until practical use. In addition, 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.

(3) Polarizing film The polarizing film used in the present invention has a transparent protective film on both sides of the polarizer and the polarizer, and the transparent protective film on the viewing side of the polarizer (viewing side transparent protective film) transmits at a wavelength of 380 nm. The rate is less than 6%.

(3-1) Viewing-side transparent protective film The transmittance at a wavelength of 380 nm of the viewing-side transparent protective film used in the present invention is less than 6%, preferably 3% or less, and more preferably 2% or less. Preferably, it is 1% or less. In the present invention, a higher UV absorption capability is achieved by combining a viewing-side transparent protective film having a transmittance of less than 6% at a wavelength of 380 nm and the viewing-side pressure-sensitive adhesive layer (containing an UV absorber). It is something that can be done. Moreover, the lower limit of the transmittance | permeability in wavelength 380nm of the visual recognition side transparent protective film is not specifically limited, The smaller is preferable from a viewpoint of an ultraviolet absorption function.

  As a material for forming the viewing-side transparent protective film, a material excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like is preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, styrene such as polystyrene and acrylonitrile / styrene copolymer (AS resin) And polymers based on polycarbonate and polycarbonate. 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. Among these, the visible-side transparent protective film is selected from the group consisting of a triacetyl cellulose film, an acrylic film (a film using an acrylic polymer), a polyethylene terephthalate film, and a polyolefin film having a cyclo or norbornene structure. At least one film is preferable, and a triacetyl cellulose film is more preferable.

  Although the thickness of a visual recognition side transparent protective film is not specifically limited, It is preferable that it is 40 micrometers or less, It is more preferable that it is 35 micrometers or less, It is further more preferable that it is 30 micrometers or less. Moreover, the lower limit value of the thickness of the viewing-side transparent protective film is not particularly limited, but is preferably 1 μm or more. It is preferable that the thickness of the viewing-side transparent protective film is in the above range because the polarizing film can be sufficiently thinned and the protective function of the polarizer is not impaired.

  It is preferable that the later-described polarizer and the viewing-side protective film are in close contact with each other through an aqueous adhesive or the like. Examples of the water-based adhesive include an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, a vinyl-based latex, a water-based polyurethane, and a water-based polyester. In addition to the above, examples of the adhesive between the polarizer and the viewing-side transparent protective film include an ultraviolet curable 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. The adhesive used in the present invention can contain a metal compound filler.

  The surface of the viewing side 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, antisticking, diffusion or antiglare.

(3-2) 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.

(3-3) Image display part side transparent protective film About the image display side 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 the image display part side protective film can be determined as appropriate, it is generally about 1 to 500 μm from the viewpoints of workability such as strength and handleability, and thin film properties.

  The polarizer and the image display unit side transparent protective film are also usually in close contact with each other through an aqueous adhesive or the like. Examples of the water-based adhesive include those described above.

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

2. Image Display Device The image display device of the present invention is characterized by using the polarizing film with an adhesive layer of the present invention.

As an example of a specific configuration of the image display device, for example, as shown in FIGS.
Cover glass or cover plastic 6 / viewing side adhesive layer 2a / viewing side transparent protective film 3a / polarizer 4 / image display unit side transparent protective film 3b / image display unit side adhesive layer 2b / liquid crystal display (LCD) or Organic EL display device (OLED) 7 (FIG. 2);
Cover glass or cover plastic 6 / adhesive layer 8a / sensor layer 9 / view side adhesive layer 2a / view side transparent protective film 3a / polarizer 4 / image display unit side transparent protective film 3b / image display unit side adhesive layer 2b / Liquid crystal display (LCD) or organic EL display (OLED) 7
(Figure 3);
Cover glass or cover plastic 6 / adhesive layer 8a / sensor layer 9 / adhesive layer 8b / sensor layer 9 / view side adhesive layer 2a / view side transparent protective film 3a / polarizer 4 / image display side transparent protective film 3b / image display part side adhesive layer 2b / liquid crystal display (LCD) or organic EL display (OLED) 7 (FIG. 4);
As described above, an image display device in which the respective layers are stacked in this order can be given. The polarizing film 1 with the pressure-sensitive adhesive layer of the present invention is “viewing-side pressure-sensitive adhesive layer 2a / viewing-side transparent protective film 3a / polarizer 4 / image display unit-side transparent protective film 3b / image display unit-side pressure-sensitive adhesive”. It refers to the portion of the agent layer 2b "and may contain a retardation film or the like other than these. When a retardation film is included, specifically, the image display unit side adhesive layer 2b and a liquid crystal display device (LCD) or an organic EL display device (OLED) 7 are laminated via an adhesive layer. can do. Moreover, in lamination | stacking of each layer, an adhesive layer and / or an adhesive layer can be used suitably.

  Examples of the image display device include a liquid crystal display device, an organic EL (electroluminescence) display device, a PDP (plasma display panel), and electronic paper. Among these, a liquid crystal display device having the above-described configuration, an organic EL ( An electroluminescence display device or the like is preferable.

  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.

Production Example 1 (Production of acrylic pressure-sensitive adhesive composition (a-1))
Photopolymerization started on a monomer mixture composed of 78 parts by weight of 2-ethylhexyl acrylate (2EHA), 18 parts by weight of N-vinyl-2-pyrrolidone (NVP), and 4 parts by weight of 2-hydroxyethyl acrylate (HEA). As an agent, 1-hydroxycyclohexyl phenyl ketone (trade name: Irgacure 184, having an absorption band at a wavelength of 200 to 370 nm, manufactured by BASF) 0.035 parts by weight, 2,2-dimethoxy-1,2-diphenylethane-1 -ON (trade name: Irgacure 651, having an absorption band at a wavelength of 200 to 380 nm, manufactured by BASF) 0.035 parts by weight, and then viscosity (measurement conditions: BH viscometer No. 5 rotor, 10 rpm, measurement temperature) (30 ° C.) is irradiated with ultraviolet rays until it reaches about 20 Pa · s, and a prepolymer in which a part of the monomer component is polymerized. A polymer composition (polymerization rate: 8%) was obtained. Next, 0.15 part by weight of hexanediol diacrylate (HDDA) and 0.3 part by weight of a silane coupling agent (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) are added to the prepolymer composition. And mixed to obtain an acrylic pressure-sensitive adhesive composition (a-1).

Production Example 2 (Production of acrylic pressure-sensitive adhesive composition (a-2))
Polymerization into a monomer mixture composed of 72 parts by weight of 2-ethylhexyl acrylate (2EHA), 1 part by weight of methacrylic acid acrylate (MMA), 12 parts by weight of N-vinylpyrrolidone (NVP), and 15 parts by weight of hydroxyethyl acrylate (HEA) As an initiator, 0.2 parts by weight of azobisbutylnitrile (AIBN) and 233 parts by weight of ethyl acetate were added and then reacted at 60 ° C. for 7 hours in a nitrogen atmosphere to partially polymerize the monomer components. A partially polymerized product was obtained. Next, 0.3 parts by weight of a silane coupling agent (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) and an isocyanate-based cross-linking agent (trade name: Takenate D110N, Mitsui) as a cross-linking agent are added to the partially polymerized product. Chemical Co., Ltd.) 0.21 part by weight was added to obtain an acrylic pressure-sensitive adhesive composition (a-2).

Production Example 3 (Production of image display unit side pressure-sensitive adhesive layer (B-1))
In a separable flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas introduction tube, 95 parts by weight of butyl acrylate, 5 parts by weight of acrylic acid, 0.2 part by weight of azobisisobutyronitrile as a polymerization initiator, and After 233 parts by weight of ethyl acetate was added, nitrogen gas was passed, and nitrogen substitution was performed for about 1 hour while stirring. Thereafter, the flask was heated to 60 ° C. and reacted for 7 hours to obtain an acrylic polymer having a weight average molecular weight (Mw) of 1.1 million.
To the acrylic polymer solution (with a solid content of 100 parts by weight), 0.8 parts by weight of trimethylolpropane tolylene diisocyanate (trade name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.) as an isocyanate crosslinking agent, A pressure-sensitive adhesive composition (solution) was prepared by adding 0.1 part by weight of a silane coupling agent (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.).
The obtained pressure-sensitive adhesive composition solution was applied onto a 38 μm thick separator (polyethylene terephthalate film whose surface was peeled) so that the thickness after drying was 12 μm, and dried at 100 ° C. for 3 minutes. The solvent was removed by layering to obtain an adhesive layer. Then, the crosslinking process was performed by heating at 50 degreeC for 48 hours. Hereinafter, this pressure-sensitive adhesive layer is referred to as “image display unit side pressure-sensitive adhesive layer (B-1)”.

Production Example 4 (Production of image display unit side pressure-sensitive adhesive layer (B-2))
The pressure-sensitive adhesive composition solution obtained in Production Example 3 was applied on a 38 μm-thick separator (polyethylene terephthalate film whose surface was release-treated) so that the thickness after drying was 15 μm. The solvent was removed by drying at 3 ° C. for 3 minutes to obtain a pressure-sensitive adhesive layer. Then, the crosslinking process was performed by heating at 50 degreeC for 48 hours. Hereinafter, this pressure-sensitive adhesive layer is referred to as “image display unit side pressure-sensitive adhesive layer (B-2)”.

Example 1
(Manufacture of pressure-sensitive adhesive composition with ultraviolet absorption function)
2,4-bis-[{4- (4-ethylhexyloxy) -4-hydroxy dissolved in butyl acrylate so as to have a solid content of 15% in the obtained acrylic pressure-sensitive adhesive composition (a-1). } -Phenyl] -6- (4-methoxyphenyl) -1,3,5-triazine (trade name: Tinosorb S, “UV absorber 1” in Tables 1 and 2, manufactured by BASF Japan Ltd.) 1.4 weight And 0.2 parts by weight of bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (trade name: Irgacure 819, having absorption resistance at wavelengths of 200 to 450 nm, manufactured by BASF Japan Ltd.) By doing this, an adhesive composition with an ultraviolet absorbing function was obtained.

The pressure-sensitive adhesive composition with an ultraviolet absorbing function is applied on the release-treated film so that the thickness after forming the pressure-sensitive adhesive layer is 150 μm, and then the surface of the pressure-sensitive adhesive composition layer A release film was bonded to the substrate. Thereafter, UV irradiation was performed under the conditions of illuminance: 6.5 mW / cm ² , light quantity: 1500 mJ / cm ² , peak wavelength: 350 nm, the pressure-sensitive adhesive composition layer was photocured, and the visible-side pressure-sensitive adhesive layer (A-1 ) Was formed.

(Production of polarizing film (P-1))
A 25 μm thick cycloolefin polymer (COP) film is bonded to the viewing side of a polarizer composed of a 5 μm thick stretched polyvinyl alcohol film impregnated with iodine using a polyvinyl alcohol-based adhesive to display an image of the polarizer. An acrylic film having a thickness of 20 μm was laminated on the part side surface using a polyvinyl alcohol-based adhesive to obtain a polarizing film (P-1). The polarization degree of the polarizing film was 99.995.

(Manufacture of polarizing film with adhesive layer)
The viewing-side pressure-sensitive adhesive layer (A-1) was laminated on the viewing side of the polarizing film (P-1) (that is, the surface of a cycloolefin polymer (COP) film having a thickness of 25 μm). The image display unit side pressure-sensitive adhesive layer (B-1) is laminated on the image display unit side surface of the polarizing film (P-1) (that is, the surface of the acrylic film having a thickness of 20 μm), and a retardation film ( Thickness: 56 μm, material: polycarbonate) and an image display unit side pressure-sensitive adhesive layer (B-2) were laminated to form a polarizing film with a pressure-sensitive adhesive layer. The obtained polarizing film with a pressure-sensitive adhesive layer is: viewing-side pressure-sensitive adhesive layer (A-1) / polarizing film (P-1) / image-displaying part-side pressure-sensitive adhesive layer (B-1) / retardation film / image-displaying part. It had the structure of the side adhesive layer (B-2).

Examples 2-3
The pressure-sensitive adhesive layer was the same as in Example 1 except that the type of the acrylic pressure-sensitive adhesive composition, the addition amount of the ultraviolet absorber 1, and the thickness after forming the visible-side pressure-sensitive adhesive layer were as shown in Table 1. An attached polarizing film was formed.

Example 4
A pressure-sensitive adhesive layer on the viewing side is provided with a pressure-sensitive adhesive in the same manner as in Example 1 except that the pressure-sensitive adhesive layer (A-1) on the visual recognition side is changed to the visual pressure-sensitive adhesive layer (A-2) obtained below. A polarizing film was formed.

(Manufacture of visual recognition side adhesive layer (A-2))
2,4-bis-[{4- (4-ethylhexyloxy) dissolved in ethyl acetate in the acrylic pressure-sensitive adhesive composition (a-2) obtained in Production Example 2 so as to have a solid content of 15%. -4-Hydroxy} -phenyl] -6- (4-methoxyphenyl) -1,3,5-triazine (trade name: Tinosorb S, manufactured by BASF Japan Ltd.) 1.4 parts by weight was added and stirred for ultraviolet rays. An adhesive composition with an absorption function was obtained.

  The pressure-sensitive adhesive composition with an ultraviolet absorbing function was applied on the release film of the release film so that the thickness after forming the pressure-sensitive adhesive layer was 150 μm, and 2 minutes at 60 ° C. and 2 minutes at 120 ° C. After making it dry partially, the visual recognition side adhesive layer (A-2) was formed by bonding the film by which the peeling process was carried out.

Examples 5-6
A polarizing film with a pressure-sensitive adhesive layer was formed in the same manner as in Example 4 except that the thickness after forming the viewing-side pressure-sensitive adhesive layer and the image display part-side pressure-sensitive adhesive layer were as shown in Table 1.

Example 7
(Manufacture of visual recognition side adhesive layer (A-3))
2,4-bis-[{4- (4-ethylhexyloxy) dissolved in butyl acrylate so as to have a solid content of 15% in the acrylic pressure-sensitive adhesive composition (a-1) obtained in Production Example 1. -4-hydroxy} -phenyl] -6- (4-methoxyphenyl) -1,3,5-triazine (trade name: Tinosorb S, manufactured by BASF Japan Ltd.) 0.7 parts by weight, Solvent Yellow 163 (KP Plastic Yellow MK) In Table 2, "UV absorber 2", manufactured by Kiwa Chemical Industry Co., Ltd., 0.2 parts by weight, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (trade name: Irgacure 819, wavelength) A pressure-sensitive adhesive composition with an ultraviolet absorbing function is obtained by adding 0.2 parts by weight of BASF Japan, which has an absorption resistance at 200 to 450 nm, and stirring. .

The pressure-sensitive adhesive composition with an ultraviolet absorbing function is applied on the release-treated film so that the thickness after forming the pressure-sensitive adhesive layer is 150 μm, and then the surface of the pressure-sensitive adhesive composition layer A release film was bonded to the substrate. Thereafter, illuminance: 6.5 mW / cm ^2, light quantity: 3000 mJ / cm ^2, the peak wavelength irradiated with ultraviolet rays under the condition of 350 nm, the pressure-sensitive adhesive composition layer by light-curing, the visible side pressure-sensitive adhesive layer (A-3 ) Was formed.

  A pressure-sensitive adhesive layer on the viewing side is provided with a pressure-sensitive adhesive in the same manner as in Example 1 except that the pressure-sensitive adhesive layer (A-1) on the viewing side is changed to the pressure-sensitive adhesive layer (A-3) obtained above. A polarizing film was formed.

Comparative Example 1
A polarizing film with a pressure-sensitive adhesive layer was prepared in the same manner as in Example 1 except that the viewing-side pressure-sensitive adhesive layer (A-1), the retardation film, and the image display unit-side pressure-sensitive adhesive layer (B-2) were not formed. Formed.

Comparative Example 2
A polarizing film with a pressure-sensitive adhesive layer was formed in the same manner as in Example 1 except that the viewing-side pressure-sensitive adhesive layer (A-1) was not formed.

Comparative Examples 3 and 4
A polarizing film with a pressure-sensitive adhesive was formed in the same manner as in Examples 1 and 4 except that no ultraviolet absorber was added to the viewing-side pressure-sensitive adhesive layers (A-1) and (A-2).

Comparative Example 5
(Manufacture of polarizing film (P-2))
A 25 μm thick triacetylcellulose film is bonded to the viewing side of a polarizer made of a stretched polyvinyl alcohol film having a thickness of 12 μm impregnated with iodine, using a polyvinyl alcohol-based adhesive, and the image display side surface of the polarizer A polarizing film (P-2) was obtained by laminating an acrylic film having a thickness of 20 μm using a polyvinyl alcohol-based adhesive. The polarization degree of the polarizing film was 99.995.

  In Example 2, a polarizing film with an adhesive was formed in the same manner as in Example 2 except that the polarizing film (P-1) was changed to the polarizing film (P-2).

  The following evaluation was performed about the obtained adhesive layer and a polarizing film with an adhesive layer.

<Polymerization rate>
The release film of the viewing-side pressure-sensitive adhesive layer obtained in Examples and Comparative Examples was peeled off, and only the viewing-side pressure-sensitive adhesive layer was placed on the weighed aluminum petri dish. The weight of (aluminum petri dish + viewing side pressure-sensitive adhesive layer) was measured, and the weight of the pressure-sensitive adhesive layer before drying was determined. After drying at 130 ° C. for 2 hours and cooling at room temperature for about 20 minutes, the weight of (aluminum petri dish + adhesive) was measured again, and the weight of the viewing-side adhesive layer after drying was determined. The polymerization rate was determined by the following calculation formula.

<Gel fraction>
About 0.1 g was collected from the viewing-side pressure-sensitive adhesive layers obtained in Examples and Comparative Examples, and wrapped in a porous tetrafluoroethylene sheet (trade name: NTF1122, manufactured by Nitto Denko Corporation) having an average pore diameter of 0.2 μm. Then, it tied up with the kite string, the weight in that case was measured (Zg), and this weight was made into the weight before immersion. The weight before immersion is the total weight of the viewing-side pressure-sensitive adhesive layer (the pressure-sensitive adhesive layer collected above), the tetrafluoroethylene sheet, and the kite string. The total weight of the tetrafluoroethylene sheet and the kite string was also measured (Yg). Next, a visible-side pressure-sensitive adhesive layer wrapped with a tetrafluoroethylene sheet and tied with a kite string (referred to as “sample”) was placed in a 50 mL container filled with ethyl acetate and allowed to stand at 23 ° C. for 7 days. Thereafter, a sample (after ethyl acetate treatment) was taken out from the container, transferred to an aluminum cup, dried in a dryer at 130 ° C. for 2 hours to remove ethyl acetate, and then weighed (Xg). The weight was defined as the weight after immersion. The gel fraction was calculated from the following formula.
Gel fraction (% by weight) = (XY) / (ZY) × 100

<Measurement of transmittance and b * value of adhesive layer on viewing side>
The release film of the viewing-side pressure-sensitive adhesive layer obtained in Examples and Comparative Examples was peeled off, and the viewing-side pressure-sensitive adhesive layer was attached to a measuring jig, and a spectrophotometer (product name: U4100, Hitachi High Co., Ltd.) (Manufactured by Technologies). For the transmittance, the transmittance at wavelengths of 380 nm, 400 nm, and 420 nm was measured (however, the wavelength of 420 nm was measured only in Examples 2 and 7).

<Residual stress>
From the viewing-side pressure-sensitive adhesive layers obtained in the examples and comparative examples, a test piece was prepared by cutting out a width of 30 mm and a length of 50 mm and forming a cylinder. This was installed with 20 mm between chucks, and the test piece was pulled 60 mm (300%) at a pulling speed of 200 mm / min (80 mm between the chucks after tension). At a position pulled 60 mm, it was fixed (held) for 300 seconds, and the stress value (N) after 300 seconds was measured. The residual stress was determined by the following formula.
Residual stress after 300 seconds = Stress value after 300 seconds (N) / (4 × thickness of test piece / 10)

<Optical reliability>
The viewing-side pressure-sensitive adhesive layers obtained in Examples 1 to 7 and Comparative Examples 3 to 5 were bonded to the COP film of the polarizing film (P-1) used in Example 1. Furthermore, a 56 μm phase difference film with a 15 μm adhesive (manufactured by Nitto Denko Corporation) was bonded to the opposite side (acrylic film side) of the polarizing film to which the viewing-side pressure-sensitive adhesive layer was bonded. Both sides of the sample were bonded with glass (trade name: S200200, thickness: 1.3 mm, size: 45 mm × 50 mm, manufactured by Matsunami Glass Industry Co., Ltd.), and autoclaved (atmospheric pressure: 0.5 MPa, temperature: 50 ° C.) for 15 minutes. Then, it injected | threw-in to the following various reliability conditions, and measured the transmittance | permeability with the spectral transmittance measuring device (Product name: DOT-3, the Murakami Color Research Laboratory Co., Ltd. product). The change in transmittance from the initial stage was determined. Evaluation was performed according to the following evaluation criteria.
(Various reliability conditions)
(Condition 1) 85 ° C. × 500 h
(Condition 2) 60 ° C., 95% × 500 h
(Condition 3) Heat shock (HS) (−40 ° C. to 85 ° C.) × 300 cycles (Condition 4) Under UV irradiation × 100 h, Illuminance: 500 W / cm ² (300 to 700 nm), Environmental temperature: 60 to 65 ° C. Environmental humidity: 50%
(Condition 5) Under Xenon irradiation × 300 h, illuminance: 2.40 W / cm ² (420 nm), environmental temperature: 50 ° C., environmental humidity: 30%
(Evaluation criteria)
○: The transmittance change amount is 2.0% or less.
(Triangle | delta): The transmittance | permeability change amount exceeds 2.0% and is 3.0% or less.
X: The transmittance change amount exceeds 3.0%.

<Glue stain, dimensional accuracy, end appearance>
The polarizing film with an adhesive layer obtained in Examples and Comparative Examples was cut into a size of 25 mm × 30 mm with a super cutter. Thereafter, the end surface processing machine (manufactured by Megaro Technica Co., Ltd.) was used to cut the four side surfaces of the cut piece by 0.05 mm to obtain a sample. Regarding the glue stain, the side surface of the sample was visually confirmed to check for the presence or absence of glue stain. The dimensional accuracy and edge appearance were observed with an optical microscope and evaluated according to the following evaluation criteria.
(Dimensional accuracy)
○: Within ± 0.3mm ×: Over ± 0.3mm (External appearance)
○: When there is no stickiness at the end when touched by hand ×: When there is stickiness at the end when touched by hand

<Curl measurement>
The sample cut into 50 mm × 40 mm was placed on a flat desk, and the curl was measured with a skimmer gauge.
(curl)
○: within ± 1.0 mm Δ: larger than ± 1.0 mm, within ± 2.0 mm ×: larger than ± 2.0 mm

In Table 1,
P-1 is a polarizing film (P-1)
P-2 is a polarizing film (P-2)
a-1 represents the acrylic pressure-sensitive adhesive composition (a-1) obtained in Production Example 1,
a-2 is the acrylic pressure-sensitive adhesive composition (a-2) obtained in Production Example 2.
The ultraviolet absorber 1 is 2,4-bis-[{4- (4-ethylhexyloxy) -4-hydroxy} -phenyl] -6- (4-methoxyphenyl) -1,3,5-triazine (trade name) : Tinosorb S, manufactured by BASF Japan)
The ultraviolet absorber 2 is Solvent Yellow 163 (KP Plastic Yellow MK, manufactured by Kiwa Chemical Industry Co., Ltd.)
B-1 is the image display unit side pressure-sensitive adhesive layer (B-1) obtained in Production Example 3,
B-2 is the image display unit side pressure-sensitive adhesive layer (B-2) obtained in Production Example 4.
Show.

DESCRIPTION OF SYMBOLS 1 Polarizing film with an adhesive layer 2a Viewing side adhesive layer 2b Image display part side adhesive layer 3a Viewing side transparent protective film 3b Image display part side transparent protective film 4 Polarizer 5 Polarizing film 6 Cover glass or cover plastic 7 Liquid crystal display Device (LCD) or organic EL display (OLED)
8a, 8b Adhesive layer 9 Sensor layer

Claims (9)

In the image display device is a polarizing film with an adhesive layer used on the viewing side from the image display unit,
The polarizing film with the pressure-sensitive adhesive layer has a pressure-sensitive adhesive layer on both sides of the polarizing film and the polarizing film,
The polarizing film has a transparent protective film on both sides of the polarizer and the polarizer,
Polarized light with pressure-sensitive adhesive layer, wherein the transparent protective film on the viewing side of the polarizer has a transmittance at a wavelength of 380 nm of less than 6%, and the pressure-sensitive adhesive layer on the viewing side of the polarizing film has an ultraviolet absorbing function the film.   The transparent protective film on the viewer side of the polarizer is at least one film selected from the group consisting of a triacetyl cellulose film, an acrylic film, a polyethylene terephthalate film, and a polyolefin film having a cyclo or norbornene structure, and The polarizing film with a pressure-sensitive adhesive layer according to claim 1, wherein the thickness is 40 μm or less.   The pressure-sensitive adhesive layer according to claim 1 or 2, wherein the thickness of the pressure-sensitive adhesive layer on the viewing side of the polarizing film is at least twice the thickness of the pressure-sensitive adhesive layer on the image display unit side of the polarizing film. Polarizing film with an agent layer.   The pressure-sensitive adhesive layer on the viewing side of the polarizing film has a transmittance at a wavelength of 380 nm of 9% or less and a transmittance at a wavelength of 400 nm of 60% or more. The polarizing film with an adhesive layer of description.   The pressure-sensitive adhesive layer on the viewing side of the polarizing film has a transmittance of 9% or less at a wavelength of 380 nm, and a transmittance of 420% or less at a wavelength of 420 nm. The polarizing film with an adhesive layer of description.   The polarizing film with a pressure-sensitive adhesive layer according to claim 1, wherein the b * value of the pressure-sensitive adhesive layer on the viewing side of the polarizing film is 3.0 or less.   The polarizing film with a pressure-sensitive adhesive layer according to claim 1, wherein the pressure-sensitive adhesive layer on the viewing side of the polarizing film contains an acrylic polymer as a base polymer.   The polarizing film with an adhesive layer according to claim 1, wherein the polarizing film is used for a liquid crystal display device or an organic EL display device.   An image display device comprising the polarizing film with a pressure-sensitive adhesive layer according to claim 1 on the viewer side from the image display unit.

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