JP2018012835A - Adhesive composition, adhesive layer, optical film with adhesive layer, image display panel, and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition, an adhesive layer, and an optical film with an adhesive layer that can maintain low contractility even under a hygrothermal environment, are free of the problems such as poor appearance or durability, have excellent antistatic properties, and can be used for image display panels.SOLUTION: An adhesive composition for image display panels contains a (meth) acrylic polymer, an ionic compound, and an antioxidant.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an adhesive composition for an image display panel, an adhesive assembly layer for an image display panel, and an optical film with an adhesive layer. The present invention also provides an image display panel in which the optical film with the pressure-sensitive adhesive layer is attached to the surface of the image display panel in contact with the pressure-sensitive adhesive layer without a conductive layer, and a liquid crystal using the image display panel The present invention relates to a display device. Furthermore, the liquid crystal display device with a touch sensing function using the image display panel of the present invention can be used as various input display devices such as mobile devices.

  In a liquid crystal display device, generally, a polarizing film is bonded to both sides of a liquid crystal cell via an adhesive layer from the image forming method. In addition, a liquid crystal display device in which a touch panel is mounted on a display screen has been put into practical use. There are various types of touch panels such as a capacitance type, a resistance film type, an optical method, an ultrasonic method, and an electromagnetic induction type, but the capacitance type is increasingly adopted. In recent years, a liquid crystal display device with a touch sensing function that incorporates a capacitance sensor as a touch sensor unit has been used.

  At the time of manufacturing the liquid crystal display device, when the polarizing film with the pressure-sensitive adhesive layer is attached to the liquid crystal cell, the release film is peeled off from the pressure-sensitive adhesive layer of the polarizing film with the pressure-sensitive adhesive layer. Static electricity is generated. The static electricity generated in this way affects the alignment of the liquid crystal layer inside the liquid crystal display device, leading to defects. Generation of static electricity can be suppressed, for example, by forming an antistatic layer on the outer surface of the polarizing film.

On the other hand, the capacitance sensor in the liquid crystal display device with a touch sensing function detects a weak capacitance formed by the transparent electrode pattern and the finger when the finger of the user approaches the surface. When a conductive layer such as an antistatic layer is provided between the transparent electrode pattern and the user's finger, the electric field between the drive electrode and the sensor electrode is disturbed, the sensor electrode capacitance becomes unstable, and the touch panel sensitivity Lowers, causing malfunction. In the liquid crystal display device with a touch sensing function, it is required to suppress the generation of static electricity and to suppress malfunction of the capacitance sensor. For example, in the liquid crystal display device with a touch sensing function, the surface resistance value is 1.0 × 10 ^{9 to} 1.0 × 10 ¹¹ Ω / □ in order to reduce the occurrence of display defects and malfunctions. It has been proposed to dispose a polarizing film having an antistatic layer on the viewing side of the liquid crystal layer (Patent Document 1).

JP2013-105154A

  According to the polarizing film having the antistatic layer described in Patent Document 1, it is possible to suppress the generation of static electricity to some extent. However, in patent document 1, since the location where the antistatic layer is disposed is farther from the fundamental position where static electricity is generated, it is not as effective as when an antistatic function is imparted to the adhesive layer.

  In addition, in a liquid crystal display device with a touch sensing function using an in-cell type liquid crystal cell, it is possible to provide conductivity from the side surface by providing a conductive structure on the side surface of the polarizing film, but when the antistatic layer is thin Since the contact area with the conductive structure on the side surface is small, it has been found that sufficient conductivity cannot be obtained and poor conduction occurs. On the other hand, it was found that when the antistatic layer becomes thicker, the touch sensor sensitivity decreases.

  The pressure-sensitive adhesive layer provided with the antistatic function is more effective in preventing static electricity unevenness by suppressing the generation of static electricity than the antistatic layer provided on the polarizing film. However, the importance of the antistatic function of the pressure-sensitive adhesive layer has been emphasized, and it has been found that the touch sensor sensitivity decreases when the conductive function of the pressure-sensitive adhesive layer is increased. In particular, it has been found that the touch sensor sensitivity decreases in a liquid crystal display device with a touch sensing function using an in-cell type liquid crystal cell. In addition, the antistatic agent (conductive agent) blended in the pressure-sensitive adhesive layer to enhance the conductive function is segregated at the interface with the polarizing film in a humid heat environment (after the humidification reliability test), or the liquid crystal cell It was found that the durability was not sufficient by shifting to the interface on the viewing side.

  In addition, when a conductive layer is not provided on the surface of a panel such as an in-cell type liquid crystal panel included in the image display panel, the polarizing film is easily charged, and thus high antistatic properties (conductivity) are required. Therefore, a large amount of an antistatic agent (conductive agent) is added to the pressure-sensitive adhesive for the polarizing film to impart antistatic properties. By adding a large amount of the antistatic agent, the surface of the pressure-sensitive adhesive layer is added. Antistatic agents may be deposited, resulting in defects in appearance such as white turbidity in a humid heat environment, and foaming or peeling in a humid heat environment.

  In addition, an optical film (for example, a polarizing film) that is bonded to a liquid crystal panel tends to shrink due to heat treatment. In particular, taking into account the shrinkage of the polarizing film itself, measures are taken to make it larger than the active area for displaying images. However, by narrowing the frame (black matrix) part of the liquid crystal panel (transition to the narrow frame panel) ), The shrinkage of the polarizing plate (excess part of the polarizing plate) is also reduced (narrow), and further accompanied by a thinning, the wet heat treatment causes the polarizing plate to shrink from the frame part and become smaller (narrower). Leakage is a problem.

  Therefore, the present invention is a pressure-sensitive adhesive composition, a pressure-sensitive adhesive layer, which can be used for image display panel applications that can maintain low shrinkage even in a humid heat environment, have no appearance defects and durability problems, and have excellent antistatic properties, And it aims at providing the optical film with an adhesive layer.

  The present invention also provides an image display panel in which the optical film with the pressure-sensitive adhesive layer is attached to the surface of the image display panel in contact with the pressure-sensitive adhesive layer without a conductive layer, and a liquid crystal display device having the image display panel The purpose is to do.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by the following pressure-sensitive adhesive composition for image display panels, and have completed the present invention.

  That is, the pressure-sensitive adhesive composition for an image display panel of the present invention is characterized by containing a (meth) acrylic polymer, an ionic compound, and an antioxidant.

  In the pressure-sensitive adhesive composition for an image display panel of the present invention, the ionic compound is preferably an ionic liquid.

  In the pressure-sensitive adhesive composition for an image display panel of the present invention, the (meth) acrylic polymer is at least selected from the group consisting of a carboxyl group-containing monomer, an amino group-containing monomer, and an amide group-containing monomer as a monomer unit. It is preferable to contain one type of monomer.

  The pressure-sensitive adhesive composition for an image display panel according to the present invention includes at least one monomer selected from the group consisting of the carboxyl group-containing monomer, the amino group-containing monomer, and the amide group-containing monomer. It is preferable to contain 0.6% by weight or more in all monomers constituting the polymer.

  The pressure-sensitive adhesive composition for an image display panel of the present invention preferably contains an isocyanate-based crosslinking agent.

  The image display panel pressure-sensitive adhesive layer of the present invention is preferably formed of the image display panel pressure-sensitive adhesive composition.

  In the optical film with an adhesive layer of the present invention, it is preferable that the adhesive layer for an image display panel is formed on at least one side of the optical film.

In the optical film with an adhesive layer of the present invention, the surface resistance of the adhesive layer for an image display panel is preferably 1 × 10 ⁸ to 1 × 10 ¹¹ Ω / □.

  In the image display panel of the present invention, it is preferable that the optical film with the pressure-sensitive adhesive layer is attached to the surface of the image display panel in contact with the pressure-sensitive adhesive layer without interposing a conductive layer.

  The liquid crystal display device of the present invention preferably has the image display panel.

  The pressure-sensitive adhesive composition for an image display panel of the present invention can maintain low shrinkage even in a humid heat environment by containing an ionic compound and an antioxidant together with a (meth) acrylic polymer as a base polymer, An adhesive layer for an image display panel having excellent antistatic properties, appearance characteristics, and durability, and an optical film with an adhesive layer using the adhesive layer can be obtained and are useful.

  Furthermore, excellent antistatic properties can be obtained without using a conductive layer on the surface of the image display panel in contact with the pressure-sensitive adhesive layer-coated optical film, and such an image display panel was used. A liquid crystal display device can be obtained and useful.

It is sectional drawing which shows an example of the optical film with an adhesive layer of this invention. It is sectional drawing which shows an example of the image display panel (in-cell type liquid crystal panel) of this invention.

  The present invention will be described below with reference to the drawings. As shown in FIG. 1, the optical film with an adhesive layer of the present invention has a surface treatment layer 1, an optical film (for example, a polarizing film) 2, an anchor layer 3, and an adhesive layer 4 in this order. The surface treatment layer 1 and the anchor layer 3 are optional. Further, as shown in FIG. 2, the image display panel of the present invention has an optical film (for example, a polarizing film) or the like formed on the image display panel (for example, an in-cell type liquid crystal panel) 5 through the pressure-sensitive adhesive layer 4. In particular, the surface of the image display panel is arranged on the outermost surface in contact with the pressure-sensitive adhesive layer 4 without interposing a conductive layer. In addition, although not described in FIG. 1, a separator can be provided on the surface of the pressure-sensitive adhesive layer 4 of the polarizing film 10 with the pressure-sensitive adhesive layer, and the surface treatment layer 1 (when the surface treatment layer 1 is not provided) The optical film (polarizing film) 2) can be provided with a surface protective film.

<Adhesive composition>
The pressure-sensitive adhesive composition for an image display panel of the present invention contains a (meth) acrylic polymer as a base polymer. The (meth) acrylic polymer usually contains an alkyl (meth) acrylate as a main component as a monomer unit. (Meth) acrylate refers to acrylate and / or methacrylate, and (meth) of the present invention has the same meaning.

  Examples of the alkyl (meth) acrylate constituting the main skeleton of the (meth) acrylic polymer include linear or branched alkyl groups having 1 to 18 carbon atoms. For example, the alkyl group includes methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, amyl group, hexyl group, cyclohexyl group, heptyl group, 2-ethylhexyl group, isooctyl group, nonyl group, decyl group. Group, isodecyl group, dodecyl group, isomyristyl group, lauryl group, tridecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, and the like. These can be used alone or in combination. The average carbon number of these alkyl groups is preferably 3-9.

  In the pressure-sensitive adhesive composition for an image display panel of the present invention, the (meth) acrylic polymer is at least selected from the group consisting of a carboxyl group-containing monomer, an amino group-containing monomer, and an amide group-containing monomer as a monomer unit. It is preferable to contain one type of monomer. Adhesive antistatic agents by using (meth) acrylic polymers containing monomers containing polar functional groups such as carboxyl group-containing monomers, amino group-containing monomers, and amide group-containing monomers as monomer units It becomes easy to hold | maintain in an agent layer, can suppress the segregation of the antistatic agent to the adhesive layer surface, and becomes a preferable aspect.

  Moreover, the pressure-sensitive adhesive composition for an image display panel of the present invention is selected from the group consisting of the (meth) acrylic polymer as a monomer unit consisting of a carboxyl group-containing monomer, an amino group-containing monomer, and an amide group-containing monomer. More preferably, it contains at least two types of monomers, and more preferably contains a carboxyl group-containing monomer and an amide group-containing monomer. By using the at least two kinds of monomers together, the antistatic agent can be easily held in the pressure-sensitive adhesive layer, and segregation of the antistatic agent on the surface of the pressure-sensitive adhesive layer can be suppressed, which is a preferred embodiment. In particular, by including a carboxyl group-containing monomer and an amide group-containing monomer, a more preferable embodiment in terms of both improvement in durability and reduction in resistance, and stability of resistance value in a humid heat environment, Become.

  In the (meth) acrylic polymer, a carboxyl group-containing monomer can be used as a monomer unit. The carboxyl group-containing monomer is a compound containing a carboxyl group in its structure and a polymerizable unsaturated double bond such as a (meth) acryloyl group or a vinyl group. Specific 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 the like. Among the carboxyl group-containing monomers, acrylic acid is preferable from the viewpoints of copolymerizability, cost, and adhesive properties (adhesive strength and the like).

  In the (meth) acrylic polymer, an amino group-containing monomer can be used as a monomer unit. The amino group-containing monomer is a compound containing an amino group in its structure and a polymerizable unsaturated double bond such as a (meth) acryloyl group or a vinyl group. Specific examples of the amino group-containing monomer include aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, and the like.

  In the (meth) acrylic polymer, an amide group-containing monomer can be used as a monomer unit. The amide group-containing monomer is a compound containing an amide group in its structure and a polymerizable unsaturated double bond such as a (meth) acryloyl group or a vinyl group. Specific examples of the amide group-containing monomer include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropylacrylamide, N-methyl (meth) acrylamide, N- Butyl (meth) acrylamide, N-hexyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylol-N-propane (meth) acrylamide, aminomethyl (meth) acrylamide, aminoethyl (meth) acrylamide, mercaapt Acrylamide monomers such as methyl (meth) acrylamide and mercaptoethyl (meth) acrylamide; N-acrylates such as N- (meth) acryloylmorpholine, N- (meth) acryloylpiperidine, N- (meth) acryloylpyrrolidine Acryloyl heterocyclic monomers; N- vinyl - pyrrolidone, N- vinyl-containing lactam monomers such as N- vinyl -ε- caprolactam. The amide group-containing monomer is preferable for satisfying the durability, and among the amide group-containing monomers, an N-vinyl group-containing lactam monomer is particularly preferable.

  An aromatic ring-containing (meth) acrylate can be further used for the (meth) acrylic polymer. An aromatic ring-containing (meth) acrylate is a compound containing an aromatic ring structure in its structure and a (meth) acryloyl group. Examples of the aromatic ring include a benzene ring, a naphthalene ring, and a biphenyl ring. The aromatic ring-containing (meth) acrylate satisfies the durability and can improve display unevenness due to white spots in the peripheral portion. Specific examples of the aromatic ring-containing (meth) acrylate include, for example, benzyl (meth) acrylate, phenyl (meth) acrylate, o-phenylphenol (meth) acrylate phenoxy (meth) acrylate, phenoxyethyl (meth) acrylate, and phenoxypropyl. (Meth) acrylate, phenoxydiethylene glycol (meth) acrylate, ethylene oxide modified nonylphenol (meth) acrylate, ethylene oxide modified cresol (meth) acrylate, phenol ethylene oxide modified (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) Acrylate, methoxybenzyl (meth) acrylate, chlorobenzyl (meth) acrylate, cresyl (meth) acrylate, polystyryl ( A) Having a benzene ring such as acrylate; hydroxyethylated β-naphthol acrylate, 2-naphthoethyl (meth) acrylate, 2-naphthoxyethyl acrylate, 2- (4-methoxy-1-naphthoxy) ethyl (meth) acrylate And those having a naphthalene ring such as biphenyl (meth) acrylate. In particular, the aromatic ring-containing (meth) acrylate is preferably benzyl (meth) acrylate or phenoxyethyl (meth) acrylate, particularly preferably phenoxyethyl (meth) acrylate, from the viewpoint of adhesive properties or durability.

  A hydroxyl group-containing monomer can be used for the (meth) acrylic polymer. The hydroxyl group-containing monomer is a compound containing a hydroxyl group in its structure and a polymerizable unsaturated double bond such as a (meth) acryloyl group or a vinyl group, more preferably a hydroxyl group-containing (meth) acrylic. System monomers. Specific examples of the hydroxyl group-containing monomer include, for example, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8- Examples include hydroxyalkyl (meth) acrylate and (4-hydroxymethylcyclohexyl) -methyl acrylate, such as hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, and 12-hydroxylauryl (meth) acrylate. Among the hydroxyl group-containing monomers, 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are preferable, and 4-hydroxybutyl (meth) acrylate is particularly preferable from the viewpoint of durability.

  These copolymerization monomers serve as reaction points with the crosslinking agent when the pressure-sensitive adhesive composition contains a crosslinking agent. In particular, the carboxyl group-containing monomer and the hydroxyl group-containing monomer are preferably used for improving the cohesiveness and heat resistance of the resulting pressure-sensitive adhesive layer because they are highly reactive with the intermolecular crosslinking agent. Moreover, a carboxyl group-containing monomer is preferable in terms of achieving both durability and reworkability, and a hydroxyl group-containing monomer is preferable in terms of reworkability.

  The (meth) acrylic polymer contains a predetermined amount of each monomer as a monomer unit in a weight ratio of all monomers (100% by weight). The weight ratio of the alkyl (meth) acrylate can be set as the remainder of the monomer other than the alkyl (meth) acrylate, and specifically, it is preferably 65% by weight or more, and more preferably 70 to 98% by weight. Setting the weight ratio of the alkyl (meth) acrylate within the above range is preferable for securing adhesiveness.

  The (meth) acrylic polymer contains, as a monomer unit, at least one monomer selected from the group consisting of the carboxyl group-containing monomer, amino group-containing monomer, and amide group-containing monomer. It is preferable to contain 0.6% by weight or more in all monomers constituting the polymer, more preferably 1% by weight or more, still more preferably 1.5% by weight or more, still more preferably 2% by weight or more, and 3% by weight. The above is particularly preferable and 4% by weight or more is most preferable. When the weight ratio of the monomer containing at least one (polar functional group) selected from the group consisting of the carboxyl group-containing monomer, amino group-containing monomer, and amide group-containing monomer is less than 0.6% by weight, When a large amount of an ionic compound, etc., is added, an antistatic agent is deposited on the surface of the pressure-sensitive adhesive layer. This is not preferable because durability problems such as the occurrence of In addition, the (meth) acrylic polymer has, as a monomer unit, at least one monomer selected from the group consisting of a carboxyl group-containing monomer, an amino group-containing monomer, and an amide group-containing monomer in a total weight of 35% by weight. % Or less, more preferably 30% by weight or less, still more preferably 25% by weight or less, still more preferably 20% by weight or less, particularly preferably 10% by weight or less, particularly preferably 7% by weight or less, 5% by weight or less is most preferable. When the weight ratio of the monomer containing at least one (polar functional group) selected from the group consisting of the carboxyl group-containing monomer, amino group-containing monomer, and amide group-containing monomer exceeds 35% by weight, adhesive strength Is too high, and reworkability is lowered, which is not preferable. In particular, 10% by weight or less is preferable, 7% by weight or less is more preferable, and 5% by weight or less is even more preferable in order to prevent the adhesive force from becoming too high. In addition, the (meth) acrylic polymer includes, as a monomer unit, at least one monomer selected from the group consisting of a carboxyl group-containing monomer, an amino group-containing monomer, and an amide group-containing monomer in all monomers. 35% by weight is more preferred, 2-30% by weight is still more preferred, 3-25% by weight is particularly preferred, and 4-20% by weight is most preferred.

  The weight ratio of the hydroxyl group-containing monomer is preferably 0.01 to 3% by weight and more preferably 0.02 to 2% by weight in the total monomer (100% by weight) of the (meth) acrylic polymer. 0.05 to 1% by weight is more preferable. If the weight ratio of the hydroxyl group-containing monomer is less than 0.01% by weight, the pressure-sensitive adhesive layer may be insufficiently cross-linked, and the durability and the adhesive properties may not be satisfied. There is a fear that you can not be satisfied.

  The weight ratio of the aromatic ring-containing (meth) acrylate is preferably 0 to 30% by weight, more preferably 3 to 25% by weight in the total monomer (100% by weight) of the (meth) acrylic polymer, 5 to 20% by weight is more preferable. When the weight ratio of the aromatic ring-containing (meth) acrylate exceeds 30% by weight, the durability may be lowered.

  In the (meth) acrylic polymer, in addition to the monomer unit, it is not particularly necessary to contain other monomer units. Alternatively, one or more copolymerization monomers having a polymerizable functional group having an unsaturated double bond such as a vinyl group can be introduced by copolymerization.

  Specific examples of such copolymerization monomers include: acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; caprolactone adducts of acrylic acid; allylsulfonic acid, 2- (meth) acrylamide-2-methyl Examples include sulfonic acid group-containing monomers such as propanesulfonic acid, (meth) acrylamide propanesulfonic acid, and sulfopropyl (meth) acrylate; and phosphoric acid group-containing monomers such as 2-hydroxyethylacryloyl phosphate.

  Further, alkylaminoalkyl (meth) acrylates such as aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate; methoxyethyl (meth) acrylate, ethoxyethyl ( Alkoxyalkyl (meth) acrylates such as meth) acrylate; N- (meth) acryloyloxymethylene succinimide, N- (meth) acryloyl-6-oxyhexamethylene succinimide, N- (meth) acryloyl-8-oxyoctamethylene succinimide, etc. Succinimide monomers; N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide and other maleimide monomers; N-methylitaconimide, N Itaconimide monomers such as ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, N-laurylitaconimide, etc. are also examples of monomers for modification purposes. Can be mentioned.

  Furthermore, as modification monomers, vinyl monomers such as vinyl acetate and vinyl propionate; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate; polyethylene glycol (meth) Glycol-based (meth) acrylates such as acrylate, polypropylene glycol (meth) acrylate, methoxyethylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate; tetrahydrofurfuryl (meth) acrylate, fluorine (meth) acrylate, silicone (meta (Meth) acrylate monomers such as acrylate and 2-methoxyethyl acrylate can also be used. Furthermore, isoprene, butadiene, isobutylene, vinyl ether and the like can be mentioned.

  Furthermore, examples of the copolymerizable monomer other than the above include silane-based monomers containing silicon atoms. 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.

  Moreover, as a copolymerization monomer, tripropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, bisphenol A diglycidyl ether di (meth) acrylate, neodymium Pentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate (Meth) acryloyl such as esterified product of (meth) acrylic acid and polyhydric alcohol such as caprolactone-modified dipentaerythritol hexa (meth) acrylate , Polyfunctional monomers having two or more unsaturated double bonds such as vinyl groups, and unsaturated groups such as (meth) acryloyl groups and vinyl groups as functional groups similar to the monomer components in the backbone of polyester, epoxy, urethane, etc. Polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate and the like to which two or more double bonds are added can also be used.

  The polymerization ratio of the copolymerization monomer in the (meth) acrylic polymer is about 0 to 10% by weight, further about 0 to 7% by weight in the total monomer (100% by weight) of the (meth) acrylic polymer, Further, it is preferably about 0 to 5% by weight.

  As the (meth) acrylic polymer, those having a weight average molecular weight (Mw) of 500,000 to 3,000,000 are usually used. Considering durability, particularly heat resistance, the weight average molecular weight (Mw) is preferably 1 million to 2.5 million, and more preferably 1.1 million to 2 million. If the weight average molecular weight (Mw) is smaller than 500,000, it is not preferable in terms of heat resistance. Moreover, when a weight average molecular weight (Mw) becomes larger than 3 million, there exists a tendency for an adhesive to become hard easily and to peel easily. In addition, a weight average molecular weight (Mw) is measured from GPC (gel permeation chromatography), and is calculated | required from the value calculated by polystyrene conversion.

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

  In solution polymerization, for example, ethyl acetate, toluene or the like is used as a polymerization solvent. As a specific example of solution polymerization, the reaction is 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.

  The polymerization initiator, chain transfer agent, emulsifier and the like used for radical polymerization are not particularly limited and can be appropriately selected and used. 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, The usage-amount is suitably adjusted according to these kinds.

<Ionic compounds>
The pressure-sensitive adhesive composition for an image display panel of the present invention is characterized by containing an ionic compound. As the ionic compound, at least one selected from the group consisting of an alkali metal salt, an ionic solid, and an ionic liquid can be preferably used, and more preferably, the ionic liquid is used alone.

<Alkali metal salt>
Since the alkali metal salt has high ion dissociation properties, it is preferable in that it exhibits excellent antistatic ability even with a small amount of addition. Examples of the alkali metal ions constituting the cation part of the alkali metal salt include lithium, sodium, and potassium ions. Of these alkali metal ions, lithium ions are preferred.

  The anion part of the alkali metal salt may be composed of an organic material or an inorganic material.

Examples of the anion part constituting the organic salt include CH ₃ COO ⁻ , CF ₃ COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , and C ₄ F ₉ SO _{3. ^{-, C 3 F 7 COO -}} , (CF 3 SO 2) (CF 3 CO) N -, - O 3 S (CF 2) 3 SO 3 -, PF 6 -, CO 3 2-, or the following general formula ( 1) to (4),
(1): (C _n F _{2n + 1} SO ₂ ) ₂ N ⁻ , where n is an integer of 1 to 10,
(2): CF ₂ (C _m F _2m SO ₂ ) ₂ N ⁻ , where m is an integer of 1 to 10,
^{_{(3): - O 3 S}} (CF 2) l SO 3 -, ( where, l is an integer of from 1 to 10),
^{_{(4) :( C p F 2p}} + 1 SO 2) N - (C q F 2q + 1 SO 2), ( where, p, q is an integer of from 1 to 10), in represented by those such as are used. In particular, an anion portion containing a fluorine atom is preferably used because an ionic compound having a good ion dissociation property can be obtained.

The anion part constituting the inorganic salt includes Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , NO ₃ ⁻ , AsF ₆ ⁻ , SbF. ₆ ⁻ , NbF ₆ ⁻ , TaF ₆ ⁻ , (CN) ₂ N ⁻ , and the like are used. As the anion moiety, (perfluoroalkylsulfonyl) imide represented by the general formula (1) such as (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , and the like is preferable. (Trifluoromethanesulfonyl) imide represented by CF ₃ SO ₂ ) ₂ N ⁻ is preferable.

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

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

<Ionic solids>
The ionic solid is an organic cation-anion salt having a melting point higher than 40 ° C., and its cation part (cation component) is composed of an organic substance, and the anion part (anion component) is an organic substance. Or an inorganic material.

  Specifically, the cation component constituting the ionic solid includes a pyridinium cation, a piperidinium cation, a pyrrolidinium cation, a cation having a pyrroline skeleton, a cation having a pyrrole skeleton, an imidazolium cation, and a tetrahydropyrimidinium cation. , Dihydropyrimidinium cation, pyrazolium cation, pyrazolinium cation, tetraalkylammonium cation, trialkylsulfonium cation, tetraalkylphosphonium cation and the like.

On the other hand, the anionic component constituting the ionic solid is, for example, Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , NO ₃ ⁻ , CH ₃ COO ⁻ , CF ₃ COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , NbF ₆ ⁻ , TaF ₆ ⁻ , (CN _{^{) 2 N -, C 4 F}} 9 SO 3 -, C 3 F 7 COO -, ((CF 3 SO 2) (CF 3 CO) N -, - O 3 S (CF 2) 3 SO 3 -, and the following General formula (1) thru | or (4),
(1): (C _n F _{2n + 1} SO ₂ ) ₂ N ⁻ , where n is an integer of 1 to 10,
(2): CF ₂ (C _m F _2m SO ₂ ) ₂ N ⁻ , where m is an integer of 1 to 10,
_{^{(3): - O 3 S}} (CF 2) l SO 3 -, ( where, l is an integer of from 1 to 10),
^{_{(4) :( C p F 2p}} + 1 SO 2) N - (C q F 2q + 1 SO 2), ( where, p, q is an integer of from 1 to 10), in represented by those such as are used. Among these, an anion component containing a fluorine atom is particularly preferably used because an ionic compound having good ion dissociation properties can be obtained.

  An ionic solid obtained by a combination of the cation component and the anion component can be used.

<Ionic liquid>
The ionic liquid refers to a molten salt (organic cation anion salt) having a melting point of 40 ° C. or lower and exhibiting a liquid state, and is preferably a liquid molten salt at room temperature (25 ° C.) or lower. In addition, the “organic cation anion salt” as used in the present invention refers to an organic salt whose cation part is composed of an organic substance, and the anion part may be an organic substance or an inorganic substance. Also good. The “organic cation anion salt” herein does not include what is called an ionic solid.

  By using the ionic liquid as an antistatic component (conductive agent, antistatic agent), an adhesive layer having a high antistatic effect can be obtained without impairing adhesive properties. Although details of the reason why excellent antistatic properties can be obtained by using an ionic liquid are not clear, the ionic liquid has a low melting point (melting point: 40 ° C. or lower) compared to a normal alkali metal salt or a solid ionic solid. Therefore, it is considered that molecular motion is easy and excellent antistatic ability can be obtained. In particular, an ionic liquid having a melting point of 40 ° C. or lower (preferably 25 ° C. or lower) is unlikely to precipitate in the pressure-sensitive adhesive in a humid heat environment or for long-term storage, and an excellent appearance and stable antistatic properties are obtained.

  Since the ionic liquid is liquid at any temperature of 40 ° C. or lower (preferably 25 ° C. or lower), it can be easily added and dispersed or dissolved in the pressure-sensitive adhesive as compared with the ionic solid. Further, since the ionic liquid has no vapor pressure (nonvolatile), it has a characteristic that the antistatic property is continuously obtained without disappearing with time. Moreover, since the ionic liquid is excellent in compatibility with the polymer, it is possible to suppress appearance defects and the like. Furthermore, ionic solids are likely to segregate (crystals are precipitated) on the surface of the pressure-sensitive adhesive layer, causing poor appearance (white turbidity) and reduced durability. It becomes.

  As said ionic liquid, what consists of an organic cation component represented by the following general formula (A)-(E) and an anion component is used preferably. An ionic liquid having these cations provides a further excellent antistatic ability.

R _a in the formula (A) represents a hydrocarbon group having 4 to 20 carbon atoms, and may be a functional group in which a part of the hydrocarbon group is substituted with a hetero atom, and R _b and R _c May be the same or different and each represents hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, and a part of the hydrocarbon group may be a functional group substituted with a hetero atom. However, when the nitrogen atom contains a double bond, there is no R _c .

R _d in the formula (B) represents a hydrocarbon group having 2 to 20 carbon atoms, and may be a functional group in which a part of the hydrocarbon group is substituted with a hetero atom, R _e , R _f And R _g may be the same or different and each represents hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, and a part of the hydrocarbon group may be a functional group substituted with a hetero atom.

R _h in the formula (C) represents a hydrocarbon group having 2 to 20 carbon atoms, and may be a functional group in which a part of the hydrocarbon group is substituted with a hetero atom, R _i , R _j , And R _k may be the same or different and each represents hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, and a part of the hydrocarbon group may be a functional group substituted with a hetero atom.

Z in the formula (D) represents a nitrogen, sulfur, or phosphorus atom, and R ₁ , R _m , R _n , and R _o are the same or different and represent a hydrocarbon group having 1 to 20 carbon atoms. In addition, a functional group in which a part of the hydrocarbon group is substituted with a hetero atom may be used. However, when Z is a sulfur atom, there is no _Ro .

R _P in the formula (E) represents a hydrocarbon group having 1 to 18 carbon atoms, a part of the hydrocarbon group may be substituted by a functional group with a heteroatom.

  Examples of the cation represented by the formula (A) include a pyridinium cation, a piperidinium cation, a pyrrolidinium cation, a cation having a pyrroline skeleton, a cation having a pyrrole skeleton, and a morpholinium cation.

  Specific examples include, for example, 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-butyl-3,4-dimethylpyridinium cation, 1-methyl-1-ethylpyrrole. Dinium cation, 1-methyl-1-hexylpyrrolidinium cation, 1-ethyl-1-hexylpyrrolidinium cation, pyrrolidinium-2-one cation, 1-propylpiperidinium cation, 1-methyl-1 -Ethylpiperidinium cation, 1-methyl-1-hexylpiperidinium cation, 2-methyl-1-pyrroline cation, 1-ethyl-2-phenylindole cation, 1,2-dimethylindole cation, 1-ethylcarbazole Cation, N-ethyl-N-methylmorph Such as Li cation.

  Examples of the cation represented by the formula (B) include an imidazolium cation, a tetrahydropyrimidinium cation, and a dihydropyrimidinium cation.

  Specific examples include, for example, 1,3-dimethylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation, 1-tetradecyl-3-methylimidazolium cation, 1- (2-methoxyethyl) -3-methylimidazolium cation, 1,3-dimethyl-1,4,5, 6-tetrahydropyrimidinium cation, 1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3,5-tetramethyl-1,4,5,6-tetrahydro Pyrimidinium cation, 1,3-dimethyl-1,4-dihydropyrimidinium cation, 1,3-dimethyl 1,6-dihydropyrimidinium cation, 1,2,3-trimethyl-1,4-dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,6-dihydropyrimidinium cation Etc.

  Examples of the cation represented by the formula (C) include a pyrazolium cation and a pyrazolinium cation.

  Specific examples include, for example, 1-methylpyrazolium cation, 3-methylpyrazolium cation, 1-ethyl-2-methylpyrazolinium cation, 1-ethyl-2,3,5-trimethylpyrazolium cation. 1-propyl-2,3,5-trimethylpyrazolium cation, 1-butyl-2,3,5-trimethylpyrazolium cation, 1-ethyl-2,3,5-trimethylpyrazolinium cation, 1 -Propyl-2,3,5-trimethylpyrazolinium cation, 1-butyl-2,3,5-trimethylpyrazolinium cation and the like.

  Examples of the cation represented by the formula (D) include a tetraalkylammonium cation, a trialkylsulfonium cation, a tetraalkylphosphonium cation, and a part of the alkyl group is substituted with an alkenyl group, an alkoxyl group, or an epoxy group. And so on.

  Specific examples include, for example, tetramethylammonium cation, tetrabutylammonium cation, tetrapentylammonium cation, tetrahexylammonium cation, triethylmethylammonium cation, tributylethylammonium cation, trimethyldecylammonium cation, N, N-diethyl-N- Methyl-N- (2-methoxyethyl) ammonium cation, glycidyltrimethylammonium cation, trimethylsulfonium cation, triethylsulfonium cation, tributylsulfonium cation, trihexylsulfonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, dimethyldecylsulfonium cation, Tetramethylphosphonium cut , Tetraethylphosphonium cation, tetrabutylphosphonium cation, tetrahexylphosphonium cation, tetraoctylphosphonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, trimethyldecylphosphonium cation, diallyldimethylammonium cation, tributyl- (2-methoxyethyl) phosphonium And cations. Among them, asymmetric such as triethylmethylammonium cation, tributylethylammonium cation, trimethyldecylammonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, dimethyldecylsulfonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, trimethyldecylphosphonium cation, etc. Tetraalkylammonium cation, trialkylsulfonium cation, tetraalkylphosphonium cation, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium cation, glycidyltrimethylammonium cation, diallyldimethylammonium cation, N, N -Dimethyl-N-ethyl-N-heptyla Monium cation, N, N-dimethyl-N-ethyl-N-nonylammonium cation, N, N-dimethyl-N-propyl-N-pentylammonium cation, N, N-dimethyl-N-propyl-N-hexylammonium cation N, N-dimethyl-N-propyl-N-heptylammonium cation, trimethylheptylammonium cation, N, N-diethyl-N-methyl-N-propylammonium cation, N, N-diethyl-N-methyl-N- Pentylammonium cation, N, N-diethyl-N-methyl-N-heptylammonium cation, N, N-diethyl-N-propyl-N-pentylammonium cation, trioctylmethylammonium cation, N-methyl-N-ethyl- N-propyl-N-pliers Ammonium cation is preferably used.

Examples of the cation represented by the formula (E) include a sulfonium cation. Further, the formula Specific examples of R _P in (E) is a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, nonyl group, decyl group, dodecyl group, tridecyl group, tetradecyl group, An octadecyl group etc. are mentioned.

On the other hand, the anion component is not particularly limited as long as it satisfies that it becomes an ionic liquid. For example, Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , NO ₃ ⁻ , CH ₃ COO ⁻ , CF ₃ COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , C ₄ F ₉ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , (C ₃ F ₇ SO ₂ ) ₂ N ⁻ , (C ₄ F ₉ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , NbF ₆ ⁻ , TaF ₆ ⁻ , HF ₂ ⁻ , (CN) ₂ N ⁻ , C ₄ F ₉ SO ₃ ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , C ₃ F ₇ COO ⁻ _{, (CF 3 SO 2) (} CF 3 CO) N -, _{^{9 H 19 COO -, (CH}} 3) 2 PO 4 -, (C 2 H 5) 2 PO 4 -, C 2 H 5 OSO 3 -, C 6 H 13 OSO 3 -, C 8 H 17 OSO 3 -, CH ₃ (OC ₂ H ₄ ) ₂ OSO ₃ ⁻ , C ₆ H ₄ (CH ₃ ) SO ₃ ⁻ , (C ₂ F ₅ ) ₃ PF ₃ ⁻ , CH ₃ CH (OH) COO ⁻ , and (FSO ₂ ) ₂ N ^- and the like are used.

Moreover, as the anion component, an anion represented by the following formula (F) can also be used.

  As an anion component, an anion component containing a fluorine atom is particularly preferably used because an ionic liquid having a low melting point is obtained.

  Specific examples of the ionic liquid used in the present invention are appropriately selected from a combination of the cation component and the anion component. For example, 1-butylpyridinium tetrafluoroborate, 1-butylpyridinium hexafluorophosphate, 1-butyl -3-methylpyridinium tetrafluoroborate, 1-butyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide, 1-butyl-3-methylpyridinium bis (pentafluoroethanesulfonyl) imide, 1-hexylpyridinium tetrafluoroborate 1-methyl-1-hexylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-hexylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-propylpiperi Nium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-ethylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-hexylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1- Ethylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-hexylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-hexylpiperidinium bis (pentafluoroethanesulfonyl) ) Imido, 2-methyl-1-pyrroline tetrafluoroborate, 1-ethyl-2-phenylindole tetrafluoroborate, 1,2-dimethylindole tetrafluoroborate, 1-ethylcarbazole tetrafluoroborate, -Ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium trifluoroacetate, 1-ethyl-3-methylimidazolium heptafluorobutyrate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium perfluorobutanesulfonate, 1-ethyl-3-methylimidazolium dicyanamide, 1-ethyl-3-methylimidazolium bis (trifluoro) (Romethanesulfonyl) imide, 1-ethyl-3-methylimidazolium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-3-methylimidazolium tris (trifluoromethanesulfonyl) methide, 1-hex Sil-3-methylimidazolium bromide, 1-hexyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium tetrafluoroborate, 1-hexyl-3-methylimidazolium hexafluorophosphate, 1 -Hexyl-3-methylimidazolium trifluoromethanesulfonate, 2-methylpyrazolium tetrafluoroporate, 1-ethyl-2,3,5-trimethylpyrazolium bis (trifluoromethanesulfonyl) imide, 1-propyl-2, 3,5-trimethylpyrazolium bis (trifluoromethanesulfonyl) imide, 1-butyl-2,3,5-trimethylpyrazolium bis (trifluoromethanesulfonyl) imide, tetrapentylammonium trifluoromethanesulfonate, Lapentylammonium bis (trifluoromethanesulfonyl) imide, tetrahexylammonium trifluoromethanesulfonate, tetrahexylammonium bis (trifluoromethanesulfonyl) imide, tetrahexylammonium trifluoromethanesulfonate, tetraheptylammonium bis (trifluoromethanesulfonyl) imide, diallyldimethyl Ammonium tetrafluoroborate, diallyldimethylammonium trifluoromethanesulfonate, diallyldimethylammonium bis (trifluoromethanesulfonyl) imide, diallyldimethylammonium bis (pentafluoroethanesulfonyl) imide, N, N-diethyl-N-methyl-N- (2- Methoxyethyl) ammonium tetrafluorobo N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium trifluoromethanesulfonate, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) ) Imide, N, N-diethyl-Nmethyl-N- (2-methoxyethyl) ammonium bis (pentafluoroethanesulfonyl) imide, glycidyltrimethylammonium trifluoromethanesulfonate, glycidyltrimethylammonium bis (trifluoromethanesulfonyl) imide, glycidyltrimethyl Ammonium bis (pentafluoroethanesulfonyl) imide, tetraoctylphosphonium trifluoromethanesulfonate, tetraoctylphosphonium bis (trifluoromethanesulfonyl) ) Imide, N, N-dimethyl-N-ethyl-N-butylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N -Dimethyl-N-ethyl-N-nonylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl-N-butylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl -N-pentylammonium bis (trifluoromethanesulfonyl) imide, trimethylheptylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-propylammonium bis (trifluoromethanesulfonyl) imi N, N-diethyl-N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl -N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, trioctylmethylammonium bis (trifluoromethanesulfonyl) imide, N-methyl-N-ethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) ) Imido, 1-butylpyridinium (trifluoromethanesulfonyl) trifluoroacetamide, 1-butyl-3-methylpyridinium (trifluoromethanesulfonyl) trifluoroacetamide, 1-ethyl-3 Methyl imidazolium (trifluoromethanesulfonyl) trifluoroacetamide, N-ethyl-N-methylmorpholinium thiocyanate, 4-ethyl-4-methylmorpholinium methyl carbonate, 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) ) Imide, etc. In particular, the use of 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide can reduce the amount of ionic compound used, for example, (meth) acrylic Even if it is 7 weight part or less with respect to 100 weight part of polymers, effects, such as outstanding antistatic property, can be provided, and it is preferable.

  In addition, the said ionic compound may be used independently and may mix and use 2 or more types.

  As for the usage-amount of the ionic compound contained in the adhesive composition for image display panels of this invention, 1.5-20 weight part is preferable with respect to 100 weight part of (meth) acrylic-type polymers, and 3-18 weight. Parts are more preferred, and 5 to 16 parts by weight are even more preferred. If the ionic compound is less than 1.5 parts by weight, the effect of improving the antistatic performance may not be sufficient. On the other hand, if the amount of the ionic compound is more than 20 parts by weight, defects in appearance such as precipitation / segregation of the ionic compound and white turbidity in the wet heat environment, foaming / peeling in the wet heat environment, and the durability are sufficient. May not be. In particular, the pressure-sensitive adhesive layer used for an image display panel without a conductive layer is required to have high antistatic properties, and therefore, it is preferable to use an ionic compound within the above range. In addition, from the viewpoint of suppression of white turbidity (humidity white turbidity) in a humid heat environment and durability, the amount of the ionic compound used is 10 parts by weight or less with respect to 100 parts by weight of the (meth) acrylic polymer. Preferably, 7 parts by weight or less is more preferable.

  In addition to the ionic compound, other antistatic agents (conductive agents) can be used as long as they do not impair the characteristics of the present invention. Examples of the other antistatic agents include ionic Examples thereof include materials capable of imparting antistatic properties such as conductive surfactant systems, conductive polymers, and conductive fine particles.

<Antioxidant>
The pressure-sensitive adhesive composition for an image display panel of the present invention is characterized by containing an antioxidant. By containing an antioxidant, main chain scission of the (meth) acrylic polymer accompanying the oxidative deterioration of the resulting pressure-sensitive adhesive layer can be suppressed, and low shrinkage can be maintained even in a humid heat environment, which is a preferred embodiment. In particular, even if it does not contain an antioxidant and contains a crosslinking agent, it is excellent in durability due to foaming and peeling in a wet heat environment and is useful.

  Examples of the antioxidant include phenol-based, phosphorus-based, sulfur-based and amine-based antioxidants, and at least one selected from these can be used. Among these, a phenolic antioxidant is preferable.

  Specific examples of the phenolic antioxidant include 2,6-di-t-butyl-p-cresol, 2,6-di-t-butyl-4-ethylphenol, 2,6 as monocyclic phenol compounds. -Dicyclohexyl-4-methylphenol, 2,6-diisopropyl-4-ethylphenol, 2,6-di-t-amyl-4-methylphenol, 2,6-di-t-octyl-4-n-propylphenol 2,6-dicyclohexyl-4-n-octylphenol, 2-isopropyl-4-methyl-6-t-butylphenol, 2-t-butyl-4-ethyl-6-t-octylphenol, 2-isobutyl-4-ethyl -6-t-hexylphenol, 2-cyclohexyl-4-n-butyl-6-isopropylphenol, styrenated mixed cresol, D 2-α-tocopherol, stearyl β- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, etc. as a bicyclic phenol compound, 2,2′-methylenebis (4-methyl-6-t-butylphenol) ), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 4,4′-thiobis (3-methyl-6-tert-butylphenol), 2,2′-thiobis (4-methyl-6) -T-butylphenol), 4,4'-methylenebis (2,6-di-t-butylphenol), 2,2'-methylenebis [6- (1-methylcyclohexyl) -p-cresol], 2,2'- Ethylidenebis (4,6-di-t-butylphenol), 2,2'-butylidenebis (2-t-butyl-4-methylphenol), 3,6-dioxaocta Methylene bis [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate], triethylene glycol bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1 , 6-hexanediol bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,2′-thiodiethylenebis [3- (3,5-di-t-butyl- 4-hydroxyphenyl) propionate], etc. as 1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5-tris (2 , 6-Dimethyl-3-hydroxy-4-tert-butylbenzyl) isocyanurate, 1,3,5-tris [(3,5-di-tert-butyl-4-hydroxy) Cyphenyl) propionyloxyethyl] isocyanurate, tris (4-t-butyl-2,6-dimethyl-3-hydroxybenzyl) isocyanurate, 1,3,5-trimethyl-2,4,6-tris (3,5 -Di-t-butyl-4-hydroxybenzyl) benzene or the like as a tetracyclic phenol compound, tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane or the like, Examples of phosphorus-containing phenol compounds include bis (3,5-di-t-butyl-4-hydroxybenzylphosphonate ethyl) calcium and bis (3,5-di-t-butyl-4-hydroxybenzylphosphonate ethyl) nickel. Can be mentioned.

  Specific examples of the phosphorus antioxidant include trioctyl phosphite, trilauryl phosphite, tristridecyl phosphite, trisisodecyl phosphite, phenyl diisooctyl phosphite, phenyl diisodecyl phosphite, phenyl di (tridecyl) Phosphite, diphenylisooctylphosphite, diphenylisodecylphosphite, diphenyltridecylphosphite, triphenylphosphite, tris (nonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, Tris (butoxyethyl) phosphite, tetratridecyl-4,4'-butylidenebis (3-methyl-6-tert-butylphenol) -diphosphite, 4,4'-isopropylidene-diphenol alkyl phosphite Sphite (wherein alkyl has about 12 to 15 carbon atoms), 4,4'-isopropylidenebis (2-t-butylphenol) di (nonylphenyl) phosphite, tris (biphenyl) phosphite, tetra (tridecyl)- 1,1,3-tris (2-methyl-5-tert-butyl-4-hydroxyphenyl) butanediphosphite, tris (3,5-di-tert-butyl-4-hydroxyphenyl) phosphite, hydrogenation -4,4'-isopropylidenediphenol polyphosphite, bis (octylphenyl) -bis [4,4'-butylidenebis (3-methyl-6-tert-butylphenol)], 1,6-hexanediol diphosphite Hexatridecyl-1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenol) difo Phyto, tris [4,4'-isopropylidenebis (2-t-butylphenol)] phosphite, tris (1,3-distearoyloxyisopropyl) phosphite, 9,10-dihydro-9-phosphaphenanthrene -10-oxide, tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylenediphosphonite, distearyl pentaerythritol diphosphite, di (nonylphenyl) pentaerythritol diphosphite, phenyl 4,4'-isopropylidenediphenol pentaerythritol diphosphite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-methyl) Phenyl) pentaerythritol diphosphite and phenylbi Such as phenol -A- pentaerythritol diphosphite, and the like.

  As the sulfur-based antioxidant, polyalkyl alcohol esters of dialkylthiodipropionate and alkylthiopropionic acid are preferably used. The dialkylthiodipropionate used here is preferably a dialkylthiodipropionate having an alkyl group having 6 to 20 carbon atoms, and the polyhydric alcohol ester of alkylthiopropionic acid is an alkyl having 4 to 20 carbon atoms. Polyalkyl alcohol esters of alkylthiopropionic acid having a group are preferred. In this case, examples of the polyhydric alcohol constituting the polyhydric alcohol ester include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, and trishydroxyethyl isocyanurate. Examples of such dialkylthiodipropionate include dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiodipropionate. On the other hand, as the polyhydric alcohol ester of alkylthiopropionic acid, for example, glycerin tributylthiopropionate, glycerin trioctylthiopropionate, glycerin trilauryl thiopropionate, glycerin tristearyl thiopropionate, trimethylol ethane tributyl Thiopropionate, trimethylol ethane trioctyl thiopropionate, trimethylol ethane trilauryl thiopropionate, trimethylol ethane tristearyl thiopropionate, pentaerythritol tetrabutyl thiopropionate, pentaerythritol tetraoctyl thiopro Pionate, pentaerythritol tetralauryl thiopropionate, pentaerythritol tetrastearyl thiopropionate, etc. It can be mentioned.

  Specific examples of the amine antioxidant include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, dimethyl succinate and 1- (2-hydroxyethyl) -4-hydroxy-2, Polycondensate of 2,6,6-tetramethylpiperidineethanol, N, N ′, N ″, N ″ ″-tetrakis- (4,6-bis- (butyl- (N-methyl-2,2, 6,6-tetramethylpiperidin-4-yl) amino) -triazin-2-yl) -4,7-diazadecane-1,10-diamine, dibutylamine 1,3,5-triazine N, N'- Polycondensate of bis (2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine and N- (2,2,6,6-tetramethyl-4-piperidyl) butylamine, poly [{6- (1,1,3, -Tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6, 6-tetramethyl-4-piperidyl) imino}], tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, 2,2,6, 6-tetramethyl-4-piperidylbenzoate, bis- (1,2,6,6-pentamethyl-4-pepyridyl) -2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n -Butyl malonate, bis- (N-methyl-2,2,6,6-tetramethyl-4-piperidyl) sebacate, 1,1 '-(1,2-ethanediyl) bis (3,3,5,5 -Tetramethylpiperazinone) (Mixed 2,2,6,6-tetramethyl-4-piperidyl / tridecyl) -1,2,3,4-butanetetracarboxylate, (mixed 1,2,2,6,6-pentamethyl-4 -Piperidyl / tridecyl) -1,2,3,4-butanetetracarboxylate, mixed [2,2,6,6-tetramethyl-4-piperidyl / β, β, β ′, β′-tetramethyl- 3,9- [2,4,8,10-tetraoxaspiro (5,5) undecane] diethyl] -1,2,3,4-butanetetracarboxylate, mixed [1,2,2,6, 6-Pentamethyl-4-piperidyl / β, β, β ′, β′-tetramethyl-3,9- [2,4,8,10-tetraoxaspiro (5,5) undecane] diethyl] -1,2 , 3,4-Butanetetracarboxy N, N'-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino] -6 -Chloro-1,3,5-triazine condensate, poly [6-N-morpholyl-1,3,5-triazine-2,4-diyl] [(2,2,6,6-tetramethyl-4- Piperidyl) imino] hexamethylene [(2,2,6,6-tetramethyl-4-piperidyl) imide], N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) hexamethylene Condensate of diamine and 1,2-dibromoethane, [N- (2,2,6,6-tetramethyl-4-piperidyl) -2-methyl-2- (2,2,6,6-tetramethyl -4-piperidyl) imino] propionamide and the like. It is possible.

  The amount of the antioxidant used is preferably 0.001 to 10 parts by weight, preferably 0.005 to 8 parts by weight, based on 100 parts by weight of the (meth) acrylic polymer. More preferably, the content is 0.01 to 5 parts by weight, still more preferably 0.1 to 4 parts by weight. If the antioxidant is less than 0.001 part by weight, the oxidative deterioration of the pressure-sensitive adhesive layer may not be suppressed, and low shrinkage and durability may not be satisfied. When a peroxide-based cross-linking agent is used, cross-linking inhibition by an antioxidant occurs, heat resistance is inferior, foaming is likely to occur, and low shrinkage may not be maintained.

  Moreover, the adhesive composition which forms an adhesive layer can contain the crosslinking agent according to a base polymer. For example, when a (meth) acrylic polymer is used as the base polymer, an organic crosslinking agent or a polyfunctional metal chelate can be used as the crosslinking agent. Examples of the organic crosslinking agent include an isocyanate crosslinking agent, a peroxide crosslinking agent, an epoxy crosslinking agent, and an imine crosslinking agent. A polyfunctional metal chelate is one in which a polyvalent metal is covalently or coordinately bonded to an organic compound. Examples of polyvalent metal atoms include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, Ti, and the like. Can be mentioned. Examples of the atom in the organic compound that is covalently bonded or coordinated include an oxygen atom, and examples of the organic compound include an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound, and a ketone compound. Among these, it is more preferable to use an isocyanate-based crosslinking agent and / or a peroxide-based crosslinking agent as the crosslinking agent, and it is particularly preferable to use an isocyanate-based crosslinking agent and a peroxide-based crosslinking agent in combination. By using an isocyanate-based cross-linking agent, cohesion, prevention of peeling in durability tests, etc. can be taken into account. By using a peroxide-based cross-linking agent, processability, reworkability, cross-linking It is excellent in stability, peelability and the like. In addition, by using an isocyanate-based crosslinking agent and a peroxide-based crosslinking agent together, and using an antioxidant here, the radical crosslinking inhibition by oxygen is effectively suppressed by the antioxidant, while the pressure-sensitive adhesive layer A three-dimensional crosslinked network can be formed efficiently. As a result, the occurrence of abnormal appearance at the end of the polarizing film can be effectively prevented, which is useful.

  As the isocyanate-based crosslinking agent, a compound having at least two isocyanate groups can be used. For example, known aliphatic polyisocyanate, alicyclic polyisocyanate, aromatic polyisocyanate and the like generally used for urethanization reaction are used.

  Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4,4- Examples include trimethylhexamethylene diisocyanate.

  Examples of the alicyclic isocyanate include 1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, and hydrogenated tolylene diisocyanate. Examples include hydrogenated tetramethylxylylene diisocyanate.

  Examples of the aromatic diisocyanate include phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, 4, Examples include 4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, xylylene diisocyanate, and the like.

  Examples of the isocyanate-based crosslinking agent include the above-mentioned diisocyanate multimers (dimers, trimers, pentamers, etc.), urethane-modified products reacted with polyhydric alcohols such as trimethylolpropane, urea-modified products, and biuret-modified products. Body, alphanate modified body, isocyanurate modified body, carbodiimide modified body and the like.

  The isocyanate-based crosslinking agent is preferably an aliphatic polyisocyanate and an aliphatic polyisocyanate-based compound that is a modified product thereof. Aliphatic polyisocyanate compounds are more flexible in cross-linking structures than other isocyanate cross-linking agents, tend to relieve stress associated with the expansion / contraction of optical films, and do not easily peel off in durability tests. . As the aliphatic polyisocyanate compound, hexamethylene diisocyanate and modified products thereof are particularly preferable.

  As a commercial item of the said isocyanate type crosslinking agent, brand name "Millionate MT" "Millionate MTL" "Millionate MR-200" "Millionate MR-400" "Coronate L" "Coronate HL" "Coronate HX" [above, Product name “Takenate D-110N” “Takenate D-120N” “Takenate D-140N” “Takenate D-160N” “Takenate D-165N” “Takenate D-170HN” “Takenate D-178N” "Takenate 500", "Takenate 600" [Mitsui Chemicals, Inc.]; These compounds may be used alone or in combination of two or more.

  As the peroxide, any radical active species can be used as long as it generates radical active species by heating or light irradiation to advance the crosslinking of the base polymer of the pressure-sensitive adhesive composition. However, in consideration of workability and stability. It is preferable to use a peroxide having a one-minute half-life temperature of 80 ° C. to 160 ° C., and more preferable to use a peroxide having a 90 ° C. to 140 ° C.

  Examples of the peroxide include di (2-ethylhexyl) peroxydicarbonate (1 minute half-life temperature: 90.6 ° C.), di (4-t-butylcyclohexyl) peroxydicarbonate (1 minute half-life). Temperature: 92.1 ° C.), di-sec-butyl peroxydicarbonate (1 minute half-life temperature: 92.4 ° C.), t-butyl peroxyneodecanoate (1 minute half-life temperature: 103.5 ° C.) ), T-hexyl peroxypivalate (1 minute half-life temperature: 109.1 ° C.), t-butyl peroxypivalate (1 minute half-life temperature: 110.3 ° C.), dilauroyl peroxide (half minute for 1 minute) Period temperature: 116.4 ° C.), di-n-octanoyl peroxide (1 minute half-life temperature: 117.4 ° C.), 1,1,3,3-tetramethylbutylperoxy-2- Tylhexanoate (1 minute half-life temperature: 124.3 ° C.), di (4-methylbenzoyl) peroxide (1 minute half-life temperature: 128.2 ° C.), dibenzoyl peroxide (1 minute half-life temperature: 130 0.0 ° C.), t-butyl peroxyisobutyrate (1 minute half-life temperature: 136.1 ° C.), 1,1-di (t-hexylperoxy) cyclohexane (1 minute half-life temperature: 149.2 ° C.) ) And the like. Especially, since the crosslinking reaction efficiency is excellent, di (4-t-butylcyclohexyl) peroxydicarbonate (1 minute half-life temperature: 92.1 ° C.), dilauroyl peroxide (1 minute half-life temperature: 116. 4 ° C.), dibenzoyl peroxide (1 minute half-life temperature: 130.0 ° C.) and the like are preferably used.

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

  In addition, as a measuring method of the peroxide decomposition amount which remained after the reaction process, it can measure by HPLC (high performance liquid chromatography), for example. More specifically, for example, about 0.2 g of the pressure-sensitive adhesive composition after the reaction treatment is taken out, immersed in 10 mL of ethyl acetate, extracted by shaking at 25 ° C. and 120 rpm for 3 hours with a shaker, and then at room temperature. Leave for 3 days. Next, 10 mL of acetonitrile was added, shaken at 120 rpm at 25 ° C. for 30 minutes, and about 10 μL of the extract obtained by filtration through a membrane filter (0.45 μm) was injected into the HPLC for analysis. The amount of peroxide can be set.

  The use amount (total amount) of the crosslinking agent is preferably 0.01 to 3 parts by weight, more preferably 0.02 to 2 parts by weight, and more preferably 0 to 100 parts by weight of the (meth) acrylic polymer. 0.03 to 1 part by weight is preferred. If the cross-linking agent is less than 0.01 parts by weight, the pressure-sensitive adhesive layer may be insufficiently cross-linked and the durability and adhesive properties may not be satisfied. On the other hand, if it exceeds 3 parts by weight, the pressure-sensitive adhesive layer becomes too hard. Durability may be reduced.

  The pressure-sensitive adhesive composition for an image display panel of the present invention can contain a silane coupling agent. The durability can be improved by using a silane coupling agent. Specific examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3, Epoxy group-containing silane coupling agent such as 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl- Amino group-containing silane coupling agents such as N- (1,3-dimethylbutylidene) propylamine, N-phenyl-γ-aminopropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltri (Meth) acrylic such as ethoxysilane Containing silane coupling agent, such as an isocyanate group-containing silane coupling agents such as 3-isocyanate propyl triethoxysilane and the like. As the exemplified silane coupling agent, an epoxy group-containing silane coupling agent is preferable.

  A silane coupling agent having a plurality of alkoxysilyl groups in the molecule can also be used. Specifically, for example, X-41-1053, X-41-1059A, X-41-1056, X-41-1805, X-41-1818, X-41-1810, X-40 manufactured by Shin-Etsu Chemical Co., Ltd. -2651 etc. are mentioned, and X-41-1810 manufactured by Shin-Etsu Chemical Co., Ltd. is particularly preferable. Silane coupling agents having a plurality of alkoxysilyl groups in these molecules are preferred because they are less volatile and effective in improving durability because they have a plurality of alkoxysilyl groups. The silane coupling agent having a plurality of alkoxysilyl groups in the molecule preferably has an epoxy group in the molecule, and more preferably has a plurality of epoxy groups in the molecule. Specific examples of the silane coupling agent having a plurality of alkoxysilyl groups in the molecule and having an epoxy group include X-41-1053, X-41-1059A, and X-41-1056 manufactured by Shin-Etsu Chemical Co., Ltd. In particular, X-41-1056 manufactured by Shin-Etsu Chemical Co., Ltd., which has a high epoxy group content, is preferred. Moreover, what has an acetoacetyl group in a molecule | numerator can also be used as a silane coupling agent. For example, A-100 manufactured by Soken Chemical Co., Ltd. may be mentioned.

  The silane coupling agent may be used alone or in combination of two or more, but the total content is 100 parts by weight of the (meth) acrylic polymer. The silane coupling agent is preferably 0.001 to 5 parts by weight, more preferably 0.01 to 1 part by weight, further preferably 0.02 to 1 part by weight, and further 0.05 to 0.6 part by weight. Is preferred. It is an amount that improves durability and moderately maintains the adhesion to glass or the like.

  The pressure-sensitive adhesive composition for an image display panel of the present invention can contain a polyether compound having a reactive silyl group. Polyether compounds are preferred because they can improve reworkability. As the polyether compound, for example, those disclosed in JP 2010-275522 A can be used.

  Further, the pressure-sensitive adhesive composition for an image display panel of the present invention may contain other known additives. For example, a polyether compound of polyalkylene glycol such as polypropylene glycol, a colorant, a powder of pigment, etc. Body, dye, surfactant, plasticizer, tackifier, surface lubricant, leveling agent, softener, anti-aging agent, light stabilizer, UV absorber, polymerization inhibitor, inorganic or organic filler, metal It can be added as appropriate according to the intended use of powder, particles, foils and the like. Moreover, you may employ | adopt the redox system which added a reducing agent within the controllable range. These additives are preferably used in an amount of 5 parts by weight or less, further 3 parts by weight or less, and further 1 part by weight or less with respect to 100 parts by weight of the (meth) acrylic polymer.

<Adhesive layer and optical film with adhesive layer>
The image display panel pressure-sensitive adhesive layer of the present invention is preferably formed of the image display panel pressure-sensitive adhesive composition. In forming the pressure-sensitive adhesive layer with the pressure-sensitive adhesive composition, it is preferable to fully consider the influence of the crosslinking treatment temperature and the crosslinking treatment time as well as adjusting the amount of the entire crosslinking agent used.

  The crosslinking treatment temperature and the crosslinking treatment time can be adjusted depending on the crosslinking agent used. The crosslinking treatment temperature is preferably 170 ° C. or lower.

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

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

  In the optical film with an adhesive layer of the present invention, it is preferable that the adhesive layer for an image display panel is formed on at least one side of the optical film. As a method for forming the pressure-sensitive adhesive layer, for example, a method in which the pressure-sensitive adhesive composition is applied to a release-processed separator, and the polymerization solvent is dried and removed to form a pressure-sensitive adhesive layer, and then transferred to an optical film, or The pressure-sensitive adhesive composition is applied to an optical film, and the polymerization solvent is dried and removed to form a pressure-sensitive adhesive layer on the optical film. In applying the pressure-sensitive adhesive, one or more solvents other than the polymerization solvent may be added as appropriate.

  As the release-treated separator, a silicone release liner is preferably used. In the step of applying the adhesive composition of the present invention on such a liner and drying to form a pressure-sensitive adhesive layer, a method for drying the pressure-sensitive adhesive is appropriately employed depending on the purpose. obtain. Preferably, a method of heating and drying the coating film is used. The heat drying temperature is preferably 40 ° C to 200 ° C, more preferably 50 ° C to 180 ° C, and particularly preferably 70 ° C to 170 ° C. By setting the heating temperature within the above range, an adhesive having excellent adhesive properties can be obtained.

  As the drying time, an appropriate time can be adopted as appropriate. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, and particularly preferably 10 seconds to 5 minutes.

  In addition, the pressure-sensitive adhesive layer can be formed after forming an anchor layer or a surface treatment layer on the surface of the optical film or performing various easy adhesion treatments such as corona treatment and plasma treatment. Moreover, you may perform an easily bonding process on the surface of an adhesive layer.

  Various methods are used as a method of forming the pressure-sensitive adhesive layer. Specifically, for example, by roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, die coater, etc. Examples thereof include an extrusion coating method.

  The thickness of the pressure-sensitive adhesive layer is not particularly limited. For example, as shown in FIG. 2, 5 to 100 μm is preferable from the viewpoint of ensuring durability and ensuring a contact area with a side conductive structure (conductive paste). -50 μm is more preferable, and 10-35 μm is still more preferable.

In addition, the surface resistance value of the pressure-sensitive adhesive layer is preferably 1 × 10 ⁸ to 1 × 10 ¹¹ Ω / □ from the viewpoint of the antistatic function and touch sensor sensitivity, and 2 × 10 ^{8 to} 5 × 10 ^10. It is preferably Ω / □, and more preferably 4 × 10 ⁸ to 1 × 10 ¹⁰ Ω / □.

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

  Examples of the constituent material of the separator include plastic 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. Although an appropriate thin leaf body etc. can be mentioned, a plastic film is used suitably from the point which is excellent in surface smoothness.

  The plastic film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer. For example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, and a vinyl chloride co-polymer are used. Examples thereof include a polymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

  The thickness of the separator is usually 5 to 200 μm, preferably about 5 to 100 μm. For the separator, silicone type, fluorine type, long chain alkyl type or fatty acid amide type release agent, mold release and antifouling treatment with silica powder, coating type, kneading type, vapor deposition type, if necessary It is also possible to perform antistatic treatment such as. 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, and fluorine treatment on the surface of the separator.

  In addition, the sheet | seat which carried out the peeling process used in preparation of the optical film with an adhesive layer can be used as a separator of an optical film with an adhesive layer as it is, and can simplify in a process surface.

  Below, the optical film with an adhesive layer of this invention is demonstrated. In addition, the optical film with an adhesive layer has an optical film (for example, polarizing film) and an adhesive layer in this order. Moreover, as shown in FIG.1 and FIG.2, it can have the surface treatment layer 1 and the anchor layer 3. FIG.

<Optical film>
As the optical film, those used for forming an image display device such as a liquid crystal display device are used, and the type thereof is not particularly limited. For example, a polarizing film is mentioned as an optical film. A polarizing film having a transparent protective film on one or both sides of a polarizer is generally used.

  The polarizer is not particularly limited, and various types can be used. 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 80 μm or less.

  A polarizer obtained by dyeing the polyvinyl alcohol film with iodine and uniaxially stretching it, for example, is prepared by immersing the polyvinyl alcohol film in an aqueous solution of iodine and stretching it 3 to 7 times the original length. Can do. 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.

  Further, as the polarizer, a thin polarizer having a thickness of 10 μm or less can 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, JP-A-51-069644, JP-A-2000-338329, WO2010 / 100917 pamphlet, PCT / JP2010 / 001460 specification, or Japanese Patent Application 2010. Examples thereof include a thin polarizing film described in Japanese Patent Application No. -269002 and Japanese Patent Application No. 2010-263692. These thin polarizing films can be obtained by a production method including a step of stretching a polyvinyl alcohol-based resin (hereinafter also referred to as PVA-based resin) layer and a stretching resin base material in a laminated state and a step of dyeing. 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, among the production methods including the step of stretching in the state of a laminate and the step of dyeing, WO2010 / 100917 pamphlet, PCT / PCT / PCT / JP 2010/001460 specification, or Japanese Patent Application No. 2010-269002 and Japanese Patent Application No. 2010-263692 as described in the manufacturing method including a step of stretching in a boric acid aqueous solution is preferable. What is obtained by the manufacturing method including the process of extending | stretching in the air auxiliary | assistant before extending | stretching in the boric acid aqueous solution as described in Japanese Patent Application No. 2010-269002 and Japanese Patent Application No. 2010-263692 is preferable.

  As a material constituting the transparent protective film, for example, a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like is used. Specific examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth) acrylic resins, cyclic Examples thereof include polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. A transparent protective film is bonded to one side of the polarizer by an adhesive layer. On the other side, as a transparent protective film, (meth) acrylic, urethane-based, acrylurethane-based, epoxy-based, silicone A thermosetting resin such as a system or an ultraviolet curable resin can be used. One or more kinds of arbitrary appropriate additives may be contained in the transparent protective film. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a mold release agent, a coloring inhibitor, a flame retardant, a nucleating agent, an antistatic agent, a pigment, and a coloring agent. The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. . When content of the said thermoplastic resin in a transparent protective film is 50 weight% or less, there exists a possibility that the high transparency etc. which a thermoplastic resin originally has cannot fully be expressed.

  The adhesive used for laminating the polarizer and the transparent protective film is not particularly limited as long as it is optically transparent. However, water-based adhesives or radical curable adhesives are suitable.

  In addition, as an optical film, for example, it is used for forming a liquid crystal display device such as a reflection plate, an anti-transmission plate, a retardation film (including wavelength plates such as 1/2 and 1/4), a visual compensation film, and a brightness enhancement film. And an optical layer that may be formed. These can be used alone as an optical film, or can be laminated on the polarizing film for practical use to use one layer or two or more layers.

  An optical film obtained by laminating the optical layer on a polarizing film can be formed by a method of laminating separately sequentially in the manufacturing process of a liquid crystal display device or the like. There is an advantage that the manufacturing process of a liquid crystal display device or the like can be improved because of excellent stability and assembly work. For the lamination, an appropriate adhesive means such as an adhesive layer can be used. When bonding the polarizing film and the other optical layer, their optical axes can be set at an appropriate arrangement angle in accordance with a target retardation characteristic or the like.

  The optical film with an adhesive layer of the present invention can be preferably used for forming various image display devices such as a liquid crystal display device. The liquid crystal display device can be formed according to the conventional method. In other words, a liquid crystal display device is generally formed by appropriately assembling components such as a display panel such as a liquid crystal cell, an optical film with an adhesive layer, and an illumination system as necessary, and incorporating a drive circuit, etc. In this invention, there is no limitation in particular except the point which uses the optical film with an adhesive layer by this invention, According to the past. As the liquid crystal cell, any type such as a TN type, STN type, π type, VA type, IPS type, or the like can be used.

  Forming an appropriate liquid crystal display device such as a liquid crystal display device in which an optical film with an adhesive layer is disposed on one side or both sides of a display panel such as the liquid crystal cell, or a lighting system using a backlight or a reflector. it can. In that case, the optical film with an adhesive layer by this invention can be installed in the one side or both sides of display panels, such as a liquid crystal cell. When optical films are provided on both sides, they may be the same or different. Further, when forming a liquid crystal display device, for example, a single layer or a suitable layer of an appropriate part such as a diffusion layer, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusion sheet, a backlight, etc. Two or more layers can be arranged.

<Anchor layer>
The anchor layer can be formed from various antistatic agent compositions, and a conductive polymer can be used as the antistatic agent for forming the anchor layer.

<Surface treatment layer>
The surface treatment layer can be provided on the side of the polarizing film where the anchor layer is not provided. The surface treatment layer can be provided on the transparent protective film used for the polarizing film, or can be provided separately from the transparent protective film. As the surface treatment layer, a hard coat layer, an antiglare treatment layer, an antireflection layer, an antisticking layer, and the like can be provided.

  The surface treatment layer is preferably a hard coat layer. As a material for forming the hard coat layer, for example, a thermoplastic resin or a material that is cured by heat or radiation can be used. Examples of the material include radiation curable resins such as thermosetting resins, ultraviolet curable resins, and electron beam curable resins. Among these, an ultraviolet curable resin that can efficiently form a cured resin layer by a simple processing operation by a curing treatment by ultraviolet irradiation is preferable. Examples of these curable resins include polyesters, acrylics, urethanes, amides, silicones, epoxies, melamines, and the like, and these monomers, oligomers, polymers, and the like are included. Radiation curable resins, particularly ultraviolet curable resins are particularly preferred because of their high processing speed and low thermal damage to the substrate. Examples of the ultraviolet curable resin preferably used include those having an ultraviolet polymerizable functional group, particularly those containing an acrylic monomer or oligomer component having 2 or more, particularly 3 to 6 functional groups. In addition, a photopolymerization initiator is blended in the ultraviolet curable resin.

  Moreover, as the surface treatment layer, an antiglare treatment layer or an antireflection layer for the purpose of improving visibility can be provided. An antiglare treatment layer or an antireflection layer can be provided on the hard coat layer. The constituent material of the antiglare layer is not particularly limited, and for example, a radiation curable resin, a thermosetting resin, a thermoplastic resin, or the like can be used. As the antireflection layer, titanium oxide, zirconium oxide, silicon oxide, magnesium fluoride, or the like is used. The antireflection layer can be provided with a plurality of layers. In addition, examples of the surface treatment layer include a sticking prevention layer.

  Conductivity can be imparted to the surface treatment layer by containing an antistatic agent. As the antistatic agent, those exemplified above can be used.

<Other layers>
In the optical film with the pressure-sensitive adhesive layer of the present invention, in addition to the above-mentioned layers, an easy-adhesion layer is provided on the surface of the optical film (polarizing film) on which the anchor layer is provided, and various types such as corona treatment and plasma treatment are provided. Easy adhesion treatment can be performed.

  The dimensional change rate (85 ° C., dry, after standing for 240 hours) of the optical film with an adhesive layer of the present invention is preferably −0.5% or less, more preferably −0.45% or less, and still more preferably − 0.4% or less. When the dimensional change rate is larger than −0.5%, the dimension of the optical film becomes smaller than the frame, and display defects such as light leakage may occur.

<Image display panel>
Generally, in-cell liquid crystal cells include a type having a conductive layer on a liquid crystal cell (semi-in-cell type) and a type having no conductive layer (full-in-cell type). The semi-in-cell type has a patterned conductive layer (for example, ITO layer) for sensor and antistatic, while the full-in-cell type has no conductive layer on the liquid crystal cell, but the polarizing plate side (adhesive layer etc.) By having a conductive layer, it contributes to antistatic properties. The present invention is preferably an image display panel (particularly an in-cell type liquid crystal panel) that is a full-in-cell type and does not have a conductive layer (without intervening) and has the optical film with the pressure-sensitive adhesive layer. However, the semi-in-cell type can be suitably used for a panel having an overcoat layer on the conductive layer and having poor antistatic properties.

  As shown in FIG. 2, the image display panel (for example, in-cell type liquid crystal panel) 20 in the present invention has an optical film 10 with an adhesive layer on at least the surface of the image display panel (in-cell type liquid crystal panel) 5. And it arrange | positions through the adhesive layer 4 without passing through an electroconductive layer.

  In the in-cell type liquid crystal panel 20, the surface treatment layer 1, the optical film (polarizing film) 2, the anchor layer 3 and the pressure-sensitive adhesive layer 4 (hereinafter referred to as “optical film (polarized light)” constituting the polarizing film 10 with the pressure-sensitive adhesive layer. The conductive structure 6 may be provided on the side surface of the film. The conduction structure 6 may be provided on all of the side surfaces of the optical film (polarizing film) or the like, or may be provided on a part thereof.

  The conductive structure 6 can suppress the generation of static electricity by connecting a potential to another suitable portion from the side of the optical film (polarizing film) or the like. Examples of the material forming the conductive structure 6 include conductive pastes such as silver, gold, and other metal pastes. In addition, a conductive adhesive and any other suitable conductive material can be used. The conductive structure 6 can also be formed in a linear shape extending from the side surface of the optical film (polarizing film) or the like.

  The in-cell type liquid crystal panel 20 may have an optical film (polarizing film), a pressure-sensitive adhesive layer, or the like on the side opposite to the optical film with the pressure-sensitive adhesive layer.

<Liquid crystal display device>
The liquid crystal display device of the present invention preferably has the image display panel. A liquid crystal display device incorporating a touch sensing function using the image display panel (particularly, an in-cell type liquid crystal panel) is appropriately provided with members for forming a liquid crystal display device such as a backlight or a reflector in an illumination system. Can be used. In particular, since the pressure-sensitive adhesive composition for image display panels of the present invention is used, there are no problems in appearance and durability due to the antistatic agent (conductive agent), and the antistatic property is excellent. The optical film can maintain low shrinkage and is useful.

  The present invention will be specifically described below with reference to production examples and examples, but the present invention is not limited to these examples. In addition, all the parts and% in each example are based on weight. The room temperature standing conditions not specifically defined below are all 23 ° C. and 65% RH.

<Measurement of weight average molecular weight of (meth) acrylic polymer>
The weight average molecular weight (Mw) of the (meth) acrylic polymer was measured by GPC (gel permeation chromatography).
・ Analyzer: HLC-8120GPC manufactured by Tosoh Corporation
Column: manufactured by Tosoh Corporation, G7000H _XL + GMH _XL + GMH _XL
・ Column size: 7.8mmφ × 30cm each 90cm in total
-Column temperature: 40 ° C
・ Flow rate: 0.8mL / min
・ Injection volume: 100 μL
・ Eluent: Tetrahydrofuran ・ Detector: Differential refractometer (RI)
Standard sample: polystyrene

[Example 1]
(Preparation of polarizing film)
A 30 μm thick polyvinyl alcohol film was immersed in warm water at 30 ° C. for 60 seconds to swell. Next, it was immersed in an aqueous solution of 0.3% concentration of iodine / potassium iodide (weight ratio = 0.5 / 8) and stretched to 3.5 times. Then, it extended | stretched so that the total draw ratio might be 6 times in 65 degreeC borate ester aqueous solution. After stretching, drying was performed in an oven at 40 ° C. for 3 minutes to obtain a polarizer having a thickness of 12 μm. A saponified 25 μm thick triacetylcellulose (TAC) film is applied to one side of the polarizer, and a corona-treated 13 μm thick cycloolefin polymer (COP) film is applied to the other side of the UV curable acrylic. A polarizing film was prepared by laminating with a system adhesive.

(Preparation of acrylic polymer)
In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, and condenser, 80.3 parts of butyl acrylate, 16 parts of phenoxyethyl acrylate, 3 parts of N-vinyl-2-pyrrolidone (NVP), acrylic acid A monomer mixture containing 0.3 part and 0.4 part of 4-hydroxybutyl acrylate was charged. Furthermore, with respect to 100 parts of the monomer mixture (solid content), 0.1 part of 2,2′-azobisisobutyronitrile as a polymerization initiator was charged with 100 parts of ethyl acetate, and nitrogen gas was added while gently stirring. After introducing and purging with nitrogen, a polymerization reaction was carried out for 8 hours while maintaining the liquid temperature in the flask at around 55 ° C. to prepare a solution of an acrylic polymer having a weight average molecular weight (Mw) of 1,500,000.

(Preparation of adhesive composition)
MPP-TFSI (Mitsubishi Materials Electronics Kasei Co., Ltd.), which is an ionic liquid, is used as a conductive agent (antistatic agent) in a usage amount shown in Table 1 with respect to a solid content of 100 parts of the acrylic polymer solution obtained above. 13 parts of methylpropylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 0.1 part of an isocyanate crosslinking agent (D160N: Takenate D-160N manufactured by Mitsui Chemicals, trimethylolpropane hexamethylene diisocyanate), benzoyl Peroxide (BPO: Niper BMT manufactured by Nippon Oil & Fats Co., Ltd.) 0.3 part, Silane coupling agent (Shin-Etsu Chemical Co., Ltd .: X-41-1810) 0.1 part, and antioxidant (Irganox 1010 manufactured by BASF) ) 0.5 parts was mixed to prepare an acrylic pressure-sensitive adhesive composition solution.

(Preparation of pressure-sensitive adhesive layer and polarizing film with pressure-sensitive adhesive layer)
Next, the thickness of the pressure-sensitive adhesive layer after drying the acrylic pressure-sensitive adhesive composition solution on one side of a polyethylene terephthalate film (separator film: manufactured by Mitsubishi Chemical Polyester Film Co., Ltd., MRF38) treated with a silicone-based release agent. Was applied at a temperature of 155 ° C. for 1 minute to form an adhesive layer on the surface of the separator film. The said adhesive layer was transcribe | transferred to the said polarizing film and produced the polarizing film with an adhesive layer.

[Examples 2 to 8 and Comparative Examples 1 to 3]
In the same manner as in Example 1, a pressure-sensitive adhesive layer was prepared based on the blending contents shown in Table 1, and a polarizing film with a pressure-sensitive adhesive layer was prepared using this. In addition, all the compounding quantities in Table 1 show the case of solid content or 100% of an active ingredient.

  The following evaluation was performed about the polarizing film with an adhesive layer obtained by the said Example and comparative example. The evaluation results are shown in Table 2.

<Surface resistance (Ω / □): Antistatic property (conductivity)>
After the separator film was peeled from the obtained polarizing film with the pressure-sensitive adhesive layer, the surface resistance value on the pressure-sensitive adhesive layer surface was measured. The measurement was performed using MCP-HT450 manufactured by Mitsubishi Chemical Analytech. The measurement results are shown in Table 2. Note that “over” in Table 2 indicates that the measurement limit of the surface resistance value was exceeded.

<Dimensional change rate>
The obtained polarizing film with an adhesive layer was cut out into 10 cm x 10 cm, and it stuck on the alkali free glass (Corning company make, EG-XG) of thickness 0.7mm using the laminator. Subsequently, the sample was autoclaved at 50 ° C. and 0.5 MPa for 15 minutes to completely adhere the sample to the alkali-free glass. The initial dimension in the polarizing plate absorption axis direction was defined as a (cm), and then the dimension of what was put in an environment at 85 ° C. for 240 hours was defined as b (cm). And the dimensional change rate was computed with the following formula.
Dimensional change rate (%) = {(ab) / a} × 100

<Durability test>
A sample obtained by cutting a polarizing film with an adhesive layer into a size of 15 inches was used as a sample. The sample was attached to a non-alkali glass having a thickness of 0.7 mm (EG-XG, manufactured by Corning) using a laminator.
Subsequently, the sample was autoclaved at 50 ° C. and 0.5 MPa for 15 minutes to completely adhere the sample to the alkali-free glass. The sample subjected to such treatment was treated for 500 hours in an atmosphere of 60 ° C. × 90% RH, and then the appearance between the polarizing film and the alkali-free glass was visually evaluated according to the following criteria.
(Evaluation criteria)
○: No change in appearance such as foaming or peeling.
Δ: There is peeling or foaming at the end, but there is no practical problem unless it is a special use.
X: Remarkably peeled off at the end, causing practical problems.

<Appearance: After wet heat>
The obtained polarizing film with a pressure-sensitive adhesive layer was put in at 60 ° C. and 95% Rh for 120 hours, taken out to room temperature, and measured for haze after 10 minutes.
(Evaluation criteria)
◎: Haze of 5 or less, good ○: Haze of 5 to 10, level having no practical problem ×: Haze of 10 or more, level having practical problem

Abbreviations in Table 1 are as follows.
BA: butyl acrylate PEA: phenoxyethyl acrylate NVP: N-vinyl-pyrrolidone AA: acrylic acid HBA: 4-hydroxybutyl acrylate D160N: trimethylolpropane hexamethylene diisocyanate adduct (Mitsui Chemicals, Takenate D160N), isocyanate -Based crosslinking agent BPO: Benzoyl peroxide (manufactured by NOF Corporation, NIPPER BMT), peroxide-based crosslinking agent MPP-TFSI: methylpropylpyrrolidinium bis (trifluoromethanesulfonyl) imide (manufactured by Mitsubishi Materials), ionic liquid EMI -TFSI: 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide (Daiichi Kogyo Seiyaku Co., Ltd.), ionic liquid MOPy-FSI: 1-octyl-4-methylpyridinium Mubis (fluorosulfonyl) imide (Daiichi Kogyo Seiyaku Co., Ltd.), ionic liquid EMI-FSI: 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide (Daiichi Kogyo Seiyaku Co., Ltd.), ionic liquid EMP-TFSI : 1-ethyl-1-methylpyrrolidinium bis (trifluoromethanesulfonyl) imide (Mitsubishi Materials Corporation), ionic solid X-41-1810: Thiol group-containing oligomer type silane coupling agent (Shin-Etsu Chemical Co., Ltd.)
Irganox 1010: Antioxidant (manufactured by BASF)

  From the evaluation results of Table 2 above, in all Examples, by using an ionic compound (the conductive agent in Table 1) and an antioxidant together, low shrinkage (small dimensional change rate), antistatic properties ( It was confirmed that excellent results were obtained in all the characteristics of low surface resistivity), appearance characteristics, and durability. On the other hand, in the comparative example, no ionic compound or antioxidant was used, so that none of the properties satisfying all the characteristics of low shrinkage, antistatic properties, appearance characteristics and durability were obtained.

1 surface treatment layer 2 optical film (polarizing film)
3 Anchor layer 4 Adhesive layer 5 Image display panel (in-cell type liquid crystal panel)
6 Conductive structure (conductive paste)
10 Polarizing film with adhesive layer 20 Image display panel (In-cell type liquid crystal panel)

Claims (10)

  A pressure-sensitive adhesive composition for an image display panel, comprising a (meth) acrylic polymer, an ionic compound, and an antioxidant.   The pressure-sensitive adhesive composition for an image display panel according to claim 1, wherein the ionic compound is an ionic liquid.   The (meth) acrylic polymer contains at least one monomer selected from the group consisting of a carboxyl group-containing monomer, an amino group-containing monomer, and an amide group-containing monomer as a monomer unit. The pressure-sensitive adhesive composition for an image display panel according to 1 or 2.   0.6% by weight or more of at least one monomer selected from the group consisting of the carboxyl group-containing monomer, amino group-containing monomer, and amide group-containing monomer in the total monomer constituting the (meth) acrylic polymer. The pressure-sensitive adhesive composition for an image display panel according to claim 3, which is contained above.   The pressure-sensitive adhesive composition for an image display panel according to claim 1, further comprising an isocyanate-based crosslinking agent.   An adhesive layer for an image display panel, which is formed from the adhesive composition for an image display panel according to any one of claims 1 to 5.   An optical film with an adhesive layer, wherein the adhesive layer for an image display panel according to claim 6 is formed on at least one side of the optical film. The surface resistance value of the pressure-sensitive adhesive layer for the image display panel is 1 × 10 ⁸ to 1 × 10 ¹¹ Ω / □, The optical film with the pressure-sensitive adhesive layer according to claim 7.   9. An image display panel, wherein the optical film with the pressure-sensitive adhesive layer according to claim 7 or 8 is adhered to the surface of the image display panel in contact with the pressure-sensitive adhesive layer without a conductive layer interposed therebetween. A liquid crystal display device comprising the image display panel according to claim 9.

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