JP6705634B2 - Adhesive composition for optical film, adhesive layer for optical film, optical film with adhesive layer, and image display device - Google Patents

Description

The present invention relates to a pressure-sensitive adhesive composition for an optical film and a pressure-sensitive adhesive layer-attached optical film in which a pressure-sensitive adhesive layer is formed on at least one surface of an optical film by the pressure-sensitive adhesive composition. Furthermore, the present invention relates to an image display device such as a liquid crystal display device, an organic EL display device and a PDP, which uses the optical film with the pressure-sensitive adhesive layer. As the optical film, it is possible to use a polarizing film, a retardation film, an optical compensation film, a brightness enhancement film, or a laminate of these.

In a liquid crystal display device or the like, it is indispensable to dispose polarizing elements on both sides of a liquid crystal cell due to its image forming method, and generally a polarizing film is attached. In addition to polarizing films, various optical elements have been used in liquid crystal panels in order to improve the display quality of displays. For example, a retardation film for preventing coloration, a viewing angle widening film for improving the viewing angle of a liquid crystal display, and a brightness enhancement film for enhancing the contrast of the display are used. These films are collectively called optical films.

When the optical member such as the optical film is attached to the liquid crystal cell, an adhesive is usually used. In addition, the adhesion between the optical film and the liquid crystal cell or the optical film usually reduces the loss of light, so that the respective materials are adhered using an adhesive. In such a case, since the adhesive has an advantage such as not requiring a drying step for fixing the optical film, the adhesive is an optical layer with an adhesive layer provided in advance as an adhesive layer on one side of the optical film. Films are commonly used. A release film is usually attached to the adhesive layer of the optical film with an adhesive layer.

As the required characteristics required for the pressure-sensitive adhesive layer, durability when the pressure-sensitive adhesive layer-attached optical film is bonded to a glass substrate of a liquid crystal panel is required, and for example, heating and usually performed as an environment acceleration test and In a durability test such as humidification, it is required that problems such as peeling and floating due to the adhesive layer do not occur.

Further, the optical film (for example, the polarizing plate) tends to shrink due to the heat treatment. Due to the contraction of the polarizing plate, the base polymer forming the pressure-sensitive adhesive layer is oriented and a phase difference occurs, which becomes a problem of display unevenness due to light leakage. Therefore, the pressure-sensitive adhesive layer is required to suppress display unevenness.

Various pressure-sensitive adhesive compositions for forming the pressure-sensitive adhesive layer of the optical film with the pressure-sensitive adhesive layer have been proposed (for example, Patent Documents 1 to 3).

On the other hand, in manufacturing a liquid crystal display device, when the pressure-sensitive adhesive layer-attached polarizing film is attached to a liquid crystal cell, the release film is peeled off from the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer-attached polarizing film. Static electricity is generated by peeling. The static electricity thus generated affects the alignment of the liquid crystal inside the liquid crystal display device and causes a defect. Also, display unevenness may occur due to static electricity when the liquid crystal display device is used. The generation of static electricity can be suppressed by, for example, forming an antistatic layer on the outer surface of the polarizing film, but in order to suppress the generation of static electricity at the fundamental position, the adhesive layer has an antistatic function. It is effective to do.

As a means for imparting an antistatic function to the pressure-sensitive adhesive layer, for example, it has been proposed to blend an ionic compound into the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer (Patent Documents 4 to 5). Patent Document 4 discloses an ionic solid containing an imidazolium cation and an inorganic anion, and Patent Document 5 discloses a liquid at room temperature such as an onium salt composed of a cation having a carbon atom of 6 to 50 containing a quaternary nitrogen atom and a fluorine atom-containing anion. It is described that the organic molten salt (1) is blended with the acrylic pressure-sensitive adhesive used for the polarizing film.

JP2012-158702A JP, 2009-215528, A JP, 2009-242767, A JP, 2009-251281, A International Publication 2007/034533 Pamphlet

Since display unevenness may occur due to static electricity when the liquid crystal display device is used, a transparent conductive layer (for example, an indium oxide:ITO layer containing tin oxide) may be formed on the glass substrate of the liquid crystal panel. Further, the transparent conductive layer functions as a shield electrode for separating the driving electric field in the liquid crystal cell and the touch panel when the liquid crystal display device is used for the touch panel, in addition to the countermeasure against the display unevenness due to static electricity. In the liquid crystal display device having such a configuration, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer-attached optical film is directly attached to the ITO layer. Therefore, the pressure-sensitive adhesive layer is required to have adhesion to the ITO layer as well as the glass substrate. In general, the ITO layer has poorer adhesion to the adhesive layer than the glass plate, and durability is often a problem. After the optical film with the pressure-sensitive adhesive layer is attached to a glass substrate, it is placed in a high temperature and high humidity condition such as 60° C. and 95% RH, and then returned to room temperature, the phenomenon that the pressure-sensitive adhesive layer becomes cloudy (humidified clouding) occurs. It became clear. The occurrence of moistening turbidity causes a reduction in the visibility of the display.

Further, the pressure-sensitive adhesive layer directly contacts the ITO layer of the liquid crystal panel and the metal such as copper of the routing wiring. Therefore, depending on the composition of the pressure-sensitive adhesive layer, the ITO layer and the metal may be corroded. Further, when corrosion occurs, there is a problem that the resistance value of the ITO layer and the leading wiring increases.

Patent Document 1 proposes a pressure-sensitive adhesive composition in which 4 to 20 parts by weight of an isocyanate crosslinking agent is mixed with 100 parts by weight of an acrylic polymer containing an aromatic ring-containing monomer and an amide group-containing monomer. However, in Patent Document 1, since a hydroxyl group-containing monomer is not contained as a monomer that forms an acrylic polymer, the acrylic polymer and the isocyanate crosslinking agent cannot directly react with each other and phase-separates, so that the pressure-sensitive adhesive is It is not preferable because it tends to become cloudy. In addition, since the pressure-sensitive adhesive composition of Patent Document 1 has a large proportion of the cross-linking agent, it tends to easily peel off in the durability test.

Further, Patent Documents 2 and 3 propose a pressure-sensitive adhesive composition containing an aromatic ring-containing (meth)acrylate, a (meth)acrylic polymer containing an amino group-containing (meth)acrylate; and a crosslinking agent. .. However, the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition of Patent Documents 2 and 3 has poor adhesion to the ITO layer and cannot satisfy durability. In Comparative Example of Patent Document 2, it is disclosed that an amide group-containing monomer is used instead of the amino group-containing (meth)acrylate, but as shown in the results of Table 2 of Patent Documents 2 and 3, In the case of using the amide group-containing monomer, the durability cannot be satisfied.

On the other hand, as described in Patent Documents 4 and 5, an antistatic function can be imparted by blending an ionic compound with the adhesive forming the adhesive layer. Further, since the liquid crystal display device is expected to be used in various temperature and humidity environments, the surface resistance value does not change even if the temperature and humidity change, and it is possible to provide a stable antistatic function for a long period of time. Is required. 2. Description of the Related Art In recent years, the number of liquid crystal display devices stacked with a touch panel and so-called on-cell touch panel liquid crystal display devices in which a sensor electrode such as an ITO layer is directly formed on a glass substrate of a liquid crystal panel are increasing. In such a case, it has been found that when the surface resistance of the pressure-sensitive adhesive layer is too low, the sensitivity of the touch panel is lowered. In order to prevent both static electricity unevenness and touch panel sensitivity reduction, it is necessary to control the surface resistance in a narrower range than before, so more stable antistatic functions are required than ever before. Is becoming

Patent Document 4 proposes to form an adhesive layer that imparts a stable antistatic function over a long period of time by using an acrylic adhesive containing an imidazolium cation, an inorganic anion and an ionic solid. However, in the pressure-sensitive adhesive layer of Patent Document 4, the adhesion to the ITO layer under humidified conditions was not sufficient. Further, Patent Document 5 proposes an acrylic pressure-sensitive adhesive containing an organic molten salt that is liquid at room temperature. However, the acrylic pressure-sensitive adhesive described in Patent Document 5 has poor dispersibility of the organic molten salt, and the stability of the antistatic function of the pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive is not sufficient.

The present invention forms a pressure-sensitive adhesive layer capable of suppressing display unevenness due to light leakage, which satisfies the durability against foaming, peeling, or humidification opaqueness with respect to both glass and transparent conductive layers. It is an object of the present invention to provide a pressure-sensitive adhesive composition for optical films.

The present invention, for both the glass and the transparent conductive layer, satisfies the durability that does not cause foaming or peeling, or moistening cloudiness, and can suppress display unevenness due to light leakage, and further, metal resistance An object of the present invention is to provide a pressure-sensitive adhesive composition for an optical film, which is capable of forming a pressure-sensitive adhesive layer capable of imparting a corrosive property and a stable antistatic function.

Further, the present invention provides an optical film with a pressure-sensitive adhesive layer having a pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive composition for an optical film, and further provides an image display device using the optical film with the pressure-sensitive adhesive layer. The purpose is to do.

As a result of intensive studies to solve the above problems, the present inventors have found the following pressure-sensitive adhesive composition for an optical film and completed the present invention.

That is, the present invention is
33% by weight or more of alkyl (meth)acrylate (a1) as a monomer unit,
Aromatic ring-containing (meth)acrylate (a2) 3 to 25% by weight,
5 to 35% by weight of N-vinyl group-containing lactam monomer (a3), and
The (meth)acrylic polymer (A) containing 0.01 to 7% by weight of the hydroxyl group-containing monomer (a4) and the crosslinking agent (B) are added to 100 parts by weight of the (meth)acrylic polymer (A). And 0.01 to 3 parts by weight of the adhesive composition for an optical film.

In the pressure-sensitive adhesive composition for an optical film, the (meth)acrylic polymer (A) may further contain 2% by weight or less of a carboxyl group-containing monomer (a5) as a monomer unit.

In the pressure-sensitive adhesive composition for optical films, the hydroxyl group-containing monomer (a4) is preferably 4-hydroxybutyl (meth)acrylate.

The crosslinking agent (B) preferably contains at least one selected from isocyanate compounds and peroxides. The isocyanate-based compound preferably contains an aliphatic polyisocyanate-based compound.

The pressure-sensitive adhesive composition for an optical film may further contain a silane coupling agent (C). The silane coupling agent (C) is preferably contained in an amount of 0.001 to 5 parts by weight with respect to 100 parts by weight of the (meth)acrylic polymer (A).

The pressure-sensitive adhesive composition for an optical film may further contain an ionic compound (D). The ionic compound (D) is preferably an alkali metal salt and/or an organic cation-anion salt. Further, the ionic compound (D) preferably contains a fluoro group-containing anion. The ionic compound (D) is preferably contained in an amount of 0.05 to 10 parts by weight based on 100 parts by weight of the (meth)acrylic polymer (A).

The present invention also relates to a pressure-sensitive adhesive layer for an optical film, which is formed of the pressure-sensitive adhesive composition for an optical film. The pressure-sensitive adhesive layer for an optical film preferably has a gel fraction of more than 70% by weight.

The present invention also relates to an optical film with a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer for an optical film is formed on at least one side of the optical film.

The present invention also relates to an image display device characterized by using at least one optical film with a pressure-sensitive adhesive layer.

The pressure-sensitive adhesive composition for an optical film of the present invention comprises, as a base polymer, an aromatic ring-containing (meth)acrylate (a2), an N-vinyl group-containing lactam monomer (a3), and a hydroxyl group-containing monomer (a4). It contains a (meth)acrylic polymer (A) which is contained in a fixed amount of a monomer unit. An optical film with a pressure-sensitive adhesive layer having a pressure-sensitive adhesive layer obtained from a pressure-sensitive adhesive composition for an optical film containing the (meth)acrylic polymer (A) having the specific composition and a predetermined amount of a crosslinking agent (B) has a heating temperature of Even in a high temperature durability test under extremely severe high temperature conditions of 95° C., it has good durability that does not cause clouding due to humidification on both glass and transparent conductive layer (ITO layer etc.) It is possible to suppress the occurrence of peeling and floating in the closed state. In particular, when the gel fraction of the pressure-sensitive adhesive layer is more than 70% by weight, the high temperature durability is preferable.

In general, the durability of a transparent conductive layer such as an ITO layer is easily affected by the composition of the ITO layer, and the amorphous ITO layer having a low tin ratio is more durable than the crystalline ITO layer having a high tin ratio. The sex tends to deteriorate. The pressure-sensitive adhesive layer obtained from the pressure-sensitive adhesive composition for an optical film can realize stable durability even with respect to the amorphous ITO layer. Further, the pressure-sensitive adhesive layer-carrying optical film having the pressure-sensitive adhesive layer of the present invention is also excellent in metal corrosion resistance with respect to the transparent conductive layer. Even when the carboxyl group-containing monomer (a5) is used, metal corrosion resistance to the transparent conductive layer can be satisfied by controlling the usage ratio.

In addition, when an image display device such as a liquid crystal display device using an optical film with an adhesive layer such as a polarizing plate with an adhesive layer is heated or humidified, peripheral unevenness may occur in the peripheral part of the liquid crystal panel or the like. Display unevenness may occur due to (white spots) such as unevenness in corners and corners, and display defects may occur. However, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive optical film of the present invention uses the pressure-sensitive adhesive composition for optical films described above. Therefore, display unevenness due to light leakage in the peripheral portion of the display screen can be suppressed.

Further, the antistatic function can be imparted to the pressure-sensitive adhesive composition for an optical film of the present invention by blending the ionic compound (D). Since the pressure-sensitive adhesive composition for an optical film of the present invention contains the (meth)acrylic polymer (A) having the specific composition and a predetermined amount of the crosslinking agent (B), the ionic compound (D) is blended. In that case, a pressure-sensitive adhesive layer capable of imparting a stable antistatic function can be formed.

The pressure-sensitive adhesive composition for an optical film of the present invention contains a (meth)acrylic polymer (A) as a base polymer. The (meth)acrylic polymer (A) usually contains an alkyl (meth)acrylate as a main component as a monomer unit. In addition, (meth)acrylate refers to acrylate and/or methacrylate, and has the same meaning as (meth) of the present invention.

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

An aromatic ring-containing (meth)acrylate (a2) is used for the (meth)acrylic polymer (A). The aromatic ring-containing (meth)acrylate (a2) 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 (a2) satisfies durability (particularly, durability against the transparent conductive layer) and can improve display unevenness due to white spots in the peripheral portion.

Specific examples of the aromatic ring-containing (meth)acrylate (a2) include, for example, benzyl (meth)acrylate, phenyl (meth)acrylate, o-phenylphenol (meth)acrylate phenoxy (meth)acrylate, phenoxyethyl (meth)acrylate. , 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 (meth)acrylate and the like having a benzene ring; hydroxyethylated β-naphthol acrylate, 2-naphthoethyl ( Those having a naphthalene ring such as (meth)acrylate, 2-naphthoxyethyl acrylate and 2-(4-methoxy-1-naphthoxy)ethyl (meth)acrylate; those having a biphenyl ring such as biphenyl (meth)acrylate.

As the aromatic ring-containing (meth)acrylate (a2), benzyl (meth)acrylate and phenoxyethyl (meth)acrylate are preferable, and phenoxyethyl (meth)acrylate is particularly preferable, from the viewpoint of adhesive properties and durability.

The N-vinyl group-containing lactam monomer (a3) is a compound containing a lactam structure and having nitrogen in the lactam structure containing a polymerizable unsaturated double bond such as a vinyl group. Specific examples of the N-vinyl group-containing lactam monomer (a3) include N-vinylpyrrolidone and N-vinyl-ε-caprolactam. The N-vinyl group-containing lactam monomer (a3) is preferable in satisfying the high temperature durability, and particularly preferable in satisfying the high temperature durability for the transparent conductive layer.

The hydroxyl group-containing monomer (a4) is a compound containing a hydroxyl group in its structure and a polymerizable unsaturated double bond such as a (meth)acryloyl group and a vinyl group. Specific examples of the hydroxyl group-containing monomer (a4) include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate. Examples thereof include hydroxyalkyl (meth)acrylate and (4-hydroxymethylcyclohexyl)-methyl acrylate, such as 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylauryl (meth)acrylate. Be done. Among the hydroxyl group-containing monomers (a4), 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferable from the viewpoint of durability, and 4-hydroxybutyl (meth)acrylate is particularly preferable.

When the pressure-sensitive adhesive composition contains a crosslinking agent, the hydroxyl group-containing monomer (a4) becomes a reaction point with the crosslinking agent. The hydroxyl group-containing monomer (a4) is highly reactive with the intermolecular crosslinking agent, and is preferably used for improving the cohesiveness and heat resistance of the obtained pressure-sensitive adhesive layer. Further, the hydroxyl group-containing monomer (a4) is preferable in terms of reworkability.

The (meth)acrylic polymer (A) contains a predetermined amount of each of the above-mentioned monomers as a monomer unit in a weight ratio of all the constituent monomers (100% by weight). The weight ratio of the alkyl (meth)acrylate (a1) can be set as the balance of the monomers other than the alkyl (meth)acrylate (a1), and is specifically 33% by weight or more. The weight ratio of the alkyl (meth)acrylate (a1) can be adjusted within the range of 33 to 91.9% by weight. It is preferable to set the weight ratio of the alkyl (meth)acrylate (a1) within the above range in order to secure the adhesiveness.

The weight ratio of the aromatic ring-containing (meth)acrylate (a2) is 3 to 25% by weight, preferably 8 to 22% by weight, and more preferably 12 to 18% by weight. If the weight ratio of the aromatic ring-containing (meth)acrylate (a2) is less than 3% by weight, display unevenness cannot be sufficiently suppressed. On the other hand, when it exceeds 25% by weight, uneven display is not sufficiently suppressed and high temperature durability is deteriorated.

The weight ratio of the N-vinyl group-containing lactam monomer (a3) is 5 to 35% by weight. From the viewpoint of high temperature durability with respect to the transparent conductive layer, the weight ratio is preferably 8.5% by weight or more, more preferably 9% by weight or more, further preferably 10.5% by weight or more, and further 13% by weight. The above is preferable. On the other hand, if the weight ratio is too large, the anchoring property to the base film such as the polarizing film tends to be lowered, so the weight ratio is preferably 30% by weight or less, and more preferably 25% by weight or less. preferable.

The weight ratio of the hydroxyl group-containing monomer (a4) is 0.01 to 7% by weight, preferably 0.1 to 5% by weight, further preferably 0.5 to 5% by weight, and further 0.5 to 3% by weight is preferred. When the weight ratio of the hydroxyl group-containing monomer (a4) is less than 0.01% by weight, the pressure-sensitive adhesive layer is insufficiently crosslinked, and high temperature durability and pressure-sensitive adhesive properties cannot be satisfied. In particular, when the weight ratio of the N-vinyl group-containing lactam monomer (a3) is high, the gel fraction tends to decrease, and heat foaming in a high temperature test tends to occur. To suppress this, the weight ratio of the hydroxyl group-containing monomer (a4) is preferably 0.5% by weight or more. Furthermore, the weight ratio of the hydroxyl group-containing monomer (a4) is 0 in relation to the weight ratio of the N-vinyl group-containing lactam monomer (a3), which is the ratio of the weight ratio {(a4)/(a3)}. It is preferably at least 1. On the other hand, when it exceeds 7% by weight, high temperature durability cannot be satisfied.

In the (meth)acrylic polymer (A), it is not particularly necessary to contain another monomer unit in addition to the monomer unit, but for the purpose of improving adhesiveness and heat resistance, (meth) ) One or more copolymerizable monomers having a polymerizable functional group having an unsaturated double bond such as an acryloyl group or a vinyl group can be introduced by copolymerization.

Examples of the copolymerization monomer include a carboxyl group-containing monomer (a5). The carboxyl group-containing monomer (a5) is a compound having a carboxyl group in its structure and a polymerizable unsaturated double bond such as a (meth)acryloyl group and a vinyl group. Specific examples of the carboxyl group-containing monomer (a5) include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid and the like. .. Among the above-mentioned carboxyl group-containing monomers (a5), acrylic acid is preferable from the viewpoint of copolymerizability, price and adhesive property.

When the pressure-sensitive adhesive composition contains a crosslinking agent together with the hydroxyl group-containing monomer (a4), the carboxyl group-containing monomer (a5) becomes a reaction point with the crosslinking agent, and the obtained adhesive layer has cohesiveness and It is preferably used for improving heat resistance. Further, the carboxyl group-containing monomer (a5) is preferable from the viewpoint of achieving both high temperature durability and reworkability.

The ratio of the carboxyl group-containing monomer (a5) in the (meth)acrylic polymer (A) is 2% by weight or less in the weight ratio of all the constituent monomers (100% by weight) of the (meth)acrylic polymer (A). Is preferred. When the weight ratio of the carboxyl group-containing monomer (a5) exceeds 2% by weight, it is not preferable in terms of metal corrosion resistance. It is also not preferable from the viewpoint of reworkability. The weight ratio of the carboxyl group-containing monomer (a5) is preferably 0.01 to 2% by weight, more preferably 0.05 to 1.5% by weight, and further preferably 0.1 to 1% by weight. It is preferably 0.1 to 0.5% by weight.

Specific examples of the copolymerization monomer other than the carboxyl group-containing monomer (a5) include: acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; caprolactone adducts of acrylic acid; allylsulfonic acid, 2 -(Meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl(meth)acrylate, and other sulfonic acid group-containing monomers; and 2-hydroxyethylacryloyl phosphate and other phosphoric acid group-containing monomers, etc. Can be mentioned.

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)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, N-(meth)acryloyl-8-oxyoctamethylenesuccinimide, etc. Succinimide-based monomers; maleimide-based monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide and N-phenylmaleimide; N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N- Examples of monomers for modification include itaconimide-based monomers such as octyl itaconimide, N-2-ethylhexyl itaconimide, N-cyclohexyl itaconimide, and N-lauryl itaconimide.

Further, as a modifying monomer, vinyl-based monomers such as vinyl acetate and vinyl propionate; cyanoacrylate-based 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, methoxy polypropylene glycol (meth)acrylate; tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, silicone (meth) ) Acrylate and (meth)acrylate monomers such as 2-methoxyethyl acrylate and the like can also be used. Further, isoprene, butadiene, isobutylene, vinyl ether and the like can be mentioned.

Furthermore, examples of copolymerizable monomers other than the above include silane-based monomers containing a silicon atom. Examples of the silane-based monomer include 3-acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, 8-vinyloctyltrimethoxysilane. , 8-vinyloctyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltriethoxysilane, 10-acryloyloxydecyltriethoxysilane and the like.

Further, as the 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, neo 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 , Polyfunctional having two or more unsaturated double bonds such as (meth)acryloyl group and vinyl group such as esterification products of (meth)acrylic acid such as caprolactone-modified dipentaerythritol hexa(meth)acrylate and polyhydric alcohol (2) or more unsaturated double bonds such as (meth)acryloyl group and vinyl group as functional groups similar to the monomer component are added to the skeleton of the organic monomer, polyester, epoxy, urethane, etc., and polyester (meth)acrylate, epoxy ( It is also possible to use (meth)acrylate, urethane (meth)acrylate and the like.

The proportion of the copolymerization monomer other than the carboxyl group-containing monomer (a5) in the (meth)acrylic polymer (A) is based on the weight ratio of all the constituent monomers (100% by weight) of the (meth)acrylic polymer (A). , 0 to 10% by weight, more preferably 0 to 7% by weight, further preferably 0 to 5% by weight.

Generally, the (meth)acrylic polymer (A) of the present invention preferably has a weight average molecular weight of 1,000,000 to 2,500,000. Considering durability, particularly heat resistance, the weight average molecular weight is preferably 1.2 to 2,000,000. When the weight average molecular weight is less than 1,000,000, it is not preferable in terms of heat resistance. When the weight average molecular weight is more than 2.5 million, the pressure sensitive adhesive tends to be hard and peeling easily occurs. Further, the weight average molecular weight (Mw)/number average molecular weight (Mn) showing the molecular weight distribution is preferably 1.8 or more and 10 or less, 1.8 to 7, and further 1.8 to 5. Preferably. When the molecular weight distribution (Mw/Mn) exceeds 10, it is not preferable in terms of durability. The weight average molecular weight and the molecular weight distribution (Mw/Mn) can be obtained from the values calculated by polystyrene measurement by GPC (gel permeation chromatography).

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

In the solution polymerization, ethyl acetate, toluene or the like is used as a polymerization solvent. As a specific example of solution polymerization, the reaction is carried out under a flow of an inert gas such as nitrogen, a polymerization initiator is added, and the reaction conditions are usually about 50 to 70° C. and about 5 to 30 hours.

The polymerization initiator, chain transfer agent, emulsifier and the like used in the radical polymerization are not particularly limited and can be appropriately selected and used. The weight average molecular weight of the (meth)acrylic polymer (A) can be controlled by the amount of the polymerization initiator and the chain transfer agent used and the reaction conditions, and the amount thereof can be adjusted appropriately according to these types. It

Examples of the polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis(2-amidinopropane)dihydrochloride, 2,2′-azobis[2-(5-methyl-2) -Imidazolin-2-yl)propane]dihydrochloride, 2,2'-azobis(2-methylpropionamidine)disulfate, 2,2'-azobis(N,N'-dimethyleneisobutylamidine),2,2 '-Azobis[N-(2-carboxyethyl)-2-methylpropionamidine] hydrate (manufactured by Wako Pure Chemical Industries, VA-057) and other azo initiators, potassium persulfate, ammonium persulfate and other persulfates , Di(2-ethylhexyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxy neodecanoate, t-hexylper Oxypivalate, t-butylperoxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, di(4 -Methylbenzoyl)peroxide, dibenzoylperoxide, t-butylperoxyisobutyrate, 1,1-di(t-hexylperoxy)cyclohexane, t-butylhydroperoxide, peroxides such as hydrogen peroxide Initiator, a combination of a persulfate and sodium bisulfite, a peroxide such as a combination of a peroxide and sodium ascorbate and a redox-based initiator in combination with a reducing agent can be mentioned, but are not limited thereto. Not something.

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

In addition, for example, 2,2′-azobisisobutyronitrile is used as a polymerization initiator to produce the (meth)acrylic polymer (A) having the above-mentioned weight average molecular weight. Is preferably about 0.06 to 0.2 parts by weight, and more preferably about 0.08 to 0.175 parts by weight, based on 100 parts by weight of the total amount of the monomer components.

Examples of the chain transfer agent include lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, and 2,3-dimercapto-1-propanol. The chain transfer agent may be used alone or in combination of two or more, but the total content is 0.1 parts by weight based on 100 parts by weight of the total amount of the monomer components. It is below the level.

As the emulsifier used in the case of emulsion polymerization, for example, sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, ammonium polyoxyethylene alkyl ether sulfate, anionic emulsifiers such as sodium polyoxyethylene alkylphenyl ether sulfate, polyoxy Examples thereof include nonionic emulsifiers such as ethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester, and polyoxyethylene-polyoxypropylene block polymer. These emulsifiers may be used alone or in combination of two or more kinds.

Furthermore, as a reactive emulsifier, as an emulsifier having a radically polymerizable functional group such as a propenyl group and an allyl ether group introduced therein, specifically, for example, Aqualon HS-10, HS-20, KH-10, BC-05. , BC-10, BC-20 (all of which are manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), ADEKA REASOAP SE10N (manufactured by Asahi Denka Co., Ltd.) and the like. Since the reactive emulsifier is incorporated into the polymer chain after the polymerization, the water resistance is improved, which is preferable. The amount of the emulsifier used is preferably 0.3 to 5 parts by weight, and more preferably 0.5 to 1 part by weight, based on 100 parts by weight of the total amount of the monomer components, and polymerization stability and mechanical stability.

The pressure-sensitive adhesive composition of the present invention contains a crosslinking agent (B). As the crosslinking agent (B), an organic crosslinking agent or a polyfunctional metal chelate can be used. Examples of the organic crosslinking agent include isocyanate crosslinking agents, peroxide crosslinking agents, epoxy crosslinking agents, imine crosslinking agents, and the like. The polyfunctional metal chelate is a polyvalent metal having a covalent bond or a coordinate bond with 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 and Ti. Can be mentioned. Examples of the atom in the organic compound that forms a covalent bond or a coordinate bond 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.

The crosslinking agent (B) is preferably an isocyanate crosslinking agent and/or a peroxide crosslinking agent.

As the isocyanate crosslinking agent (B), a compound having at least two isocyanate groups can be used. For example, known aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates and the like which are 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-trimethyl. Hexamethylene diisocyanate and the like can be mentioned.

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, hydrogenated tolylene diisocyanate hydrogen. Examples thereof include added tetramethylxylylene diisocyanate.

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

As the isocyanate-based cross-linking agent (B), a multimer (dimer, trimer, pentamer, etc.) of the above diisocyanate, a urethane modified product obtained by reacting with a polyhydric alcohol such as trimethylolpropane, or a urea modified product is used. Body, biuret modified product, alphanate modified product, isocyanurate modified product, carbodiimide modified product and the like.

Examples of commercially available products of the isocyanate cross-linking agent (B) include, for example, trade names “Millionate MT”, “Millionate MTL”, “Millionate MR-200”, “Millionate MR-400”, “Coronate L”, “Coronate HL”, and “Coronate HX” [ As above, manufactured by Nippon Polyurethane Industry Co., Ltd.; trade 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" [above, manufactured by Mitsui Chemicals, Inc.]; and the like. These compounds may be used alone or in combination of two or more.

As the isocyanate cross-linking agent (B), an aliphatic polyisocyanate and a modified aliphatic polyisocyanate compound are preferable. The aliphatic polyisocyanate-based compound has a more flexible cross-linking structure than other isocyanate-based cross-linking agents, easily relaxes the stress associated with the expansion/contraction of the optical film, and does not easily peel off in the durability test. .. As the aliphatic polyisocyanate compound, hexamethylene diisocyanate and its modified products are particularly preferable.

The peroxide can be appropriately used as long as it generates a radical active species by heating or light irradiation to promote crosslinking of the base polymer of the pressure-sensitive adhesive composition, but 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, more preferably 90°C to 140°C.

Examples of the peroxide that can be used 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 peroxy neodecanoate (1 minute half-life temperature: 103 0.5°C), t-hexylperoxypivalate (1 minute half-life temperature: 109.1°C), t-butylperoxypivalate (1 minute half-life temperature: 110.3°C), dilauroyl peroxide ( 1-minute half-life temperature: 116.4°C), di-n-octanoyl peroxide (1-minute half-life temperature: 117.4°C), 1,1,3,3-tetramethylbutylperoxy-2-ethyl Hexanoate (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° C.), t-butylperoxyisobutyrate (1 minute half-life temperature: 136.1° C.), 1,1-di(t-hexylperoxy)cyclohexane (1 minute half-life temperature: 149.2° C.) Etc. Among these, since the crosslinking reaction efficiency is particularly 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 half-life of the peroxide is an index showing the decomposition rate of the peroxide, and means the time until the residual amount of the peroxide becomes half. The decomposition temperature for obtaining a half-life at an arbitrary time and the half-life time at an arbitrary temperature are described in the manufacturer's catalog, etc., for example, NIPPON YOY CORPORATION's "Organic peroxide catalog 9th edition". (May 2003)” and the like.

The amount of the crosslinking agent (B) used is preferably 0.01 to 3 parts by weight, more preferably 0.02 to 2 parts by weight, and further preferably 100 to 2 parts by weight of the (meth)acrylic polymer (A). 0.03 to 1 part by weight is preferable. When the amount of the cross-linking agent (B) is less than 0.01 parts by weight, the pressure-sensitive adhesive layer may be insufficiently cross-linked, and durability and adhesive properties may not be satisfied, while when it is more than 3 parts by weight, the pressure-sensitive adhesive layer may be insufficient. It tends to be too hard and the durability tends to decrease.

The above isocyanate-based cross-linking agents may be used alone or in a mixture of two or more, and the total content is the (meth)acrylic polymer (A)100. It is preferable that the isocyanate cross-linking agent is contained in an amount of 0.01 to 2 parts by weight, more preferably 0.02 to 2 parts by weight, and even more preferably 0.05 to 1.5 parts by weight. More preferably, it is contained in parts. It may be appropriately contained in consideration of cohesive force, prevention of peeling in a durability test, and the like.

The above-mentioned peroxides may be used alone or in combination of two or more, but the total content is 100 parts by weight of the (meth)acrylic polymer (A). The amount of the peroxide is 0.01 to 2 parts by weight, preferably 0.04 to 1.5 parts by weight, and more preferably 0.05 to 1 part by weight. .. In order to adjust workability, reworkability, cross-linking stability, releasability, etc., it is appropriately selected within this range.

As a method of measuring the amount of peroxide decomposition remaining after the reaction treatment, for example, HPLC (high performance liquid chromatography) can be used.

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, shake-extracted at 120 rpm for 3 hours at 25° C. on a shaker, and then extracted at room temperature. Let stand for 3 days. Next, 10 mL of acetonitrile was added, and the mixture was shaken at 120 rpm for 30 minutes at 25° C., and about 10 μL of the extract obtained by filtering with a membrane filter (0.45 μm) was injected into HPLC for analysis, and after the reaction treatment, It can be a peroxide amount.

The pressure-sensitive adhesive composition of the present invention may contain a silane coupling agent (C). The durability can be improved by using the silane coupling agent (C). Specific examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2-(3. Epoxy group-containing silane coupling agents 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 Examples thereof include (meth)acrylic group-containing silane coupling agents such as ethoxysilane, and isocyanate group-containing silane coupling agents such as 3-isocyanatepropyltriethoxysilane. As the silane coupling agent exemplified above, an epoxy group-containing silane coupling agent is preferable.

Further, as the silane coupling agent (C), one having a plurality of alkoxysilyl groups in the molecule can be used. Specifically, for example, Shin-Etsu Chemical Co., Ltd. X-41-1053, X-41-1059A, X-41-1056, X-41-1805, X-41-1818, X-41-1810, X-40. -2651 etc. are mentioned. A silane coupling agent having a plurality of alkoxysilyl groups in these molecules does not easily volatilize, and since it has a plurality of alkoxysilyl groups, it is effective in improving durability and is preferable. In particular, the durability is also suitable when the adherend of the pressure-sensitive adhesive layer-attached optical film is a transparent conductive layer (for example, ITO) in which an alkoxysilyl group is less likely to react than glass. 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. The silane coupling agent having a plurality of alkoxysilyl groups in the molecule and having an epoxy group tends to have good durability even when the adherend is a transparent conductive layer (for example, ITO). 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., which has a high epoxy group content, is preferable.

The silane coupling agent (C) may be used alone or in combination of two or more, but the total content is the (meth)acrylic polymer (A)100. The silane coupling agent is preferably 0.001 to 5 parts by weight, more preferably 0.01 to 1 part by weight, still more preferably 0.02 to 1 part by weight, and even more preferably 0.05 to 1 part by weight. ˜0.6 parts by weight is preferred. It is an amount that improves durability and maintains an appropriate adhesive force to the glass and the transparent conductive layer.

The pressure-sensitive adhesive composition of the present invention can contain an ionic compound (D). As the ionic compound (D), an alkali metal salt and/or an organic cation-anion salt can be preferably used. As the alkali metal salt, organic and inorganic salts of alkali metal can be used. The term "organic cation-anion salt" used in the present invention refers to an organic salt in which the cation portion is composed of an organic substance, and the anion portion may be an organic substance or an inorganic substance. It may be. The "organic cation-anion salt" is also called an ionic liquid or an ionic solid.

<Alkali metal salt>
Examples of the alkali metal ion forming the cation portion of the alkali metal salt include lithium, sodium and potassium ions. Among these alkali metal ions, lithium ion is preferable.

The anion part of the alkali metal salt may be composed of an organic material or an inorganic material. Examples of the anion moiety forming the organic salt include CH ₃ COO ⁻ , CF ₃ COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , 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 from 1 to 10),
_{(2): CF 2 (C} m F 2m SO 2) 2 N - ( where, m is an integer of from 1 to 10),
^{_{(3): - O 3 S}} (CF 2) l SO 3 - ( where, l is an integer of from 1 to 10),
^{_{(4) :( C p F 2p}} + 1 SO 2) N - (C q F 2q + 1 SO 2), ( where, p, q is an integer of from 1 to 10), in represented by those such as are used. In particular, the anion moiety containing a fluorine atom is preferably used because an ionic compound having a good ion dissociation property can be obtained. Examples of the anion moiety forming the inorganic salt include 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. Examples of the anionic ^{_{portion, (CF 3 SO 2) 2}} N -, (C 2 F 5 SO 2) 2 N -, wherein represented by formula (1) etc., (perfluoroalkyl sulfonyl) imide are preferable, especially ( (Trifluoromethanesulfonyl)imide represented by CF ₃ SO ₂ ) ₂ N ⁻ is preferable.

Specific examples of the organic salt of an alkali metal include sodium acetate, sodium alginate, sodium ligninsulfonate, sodium toluenesulfonate, LiCF ₃ SO ₃ , Li(CF ₃ SO ₂ ) ₂ N 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 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, Li (CF 3 SO 2)} 2 N, Li (C 2 F 5 SO 2) 2 N, Li (C 4 F 9 SO ₂ ) A fluorine-containing lithium imide salt such as ₂ N is more preferable, and a (perfluoroalkylsulfonyl)imide lithium salt is particularly preferable.

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

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

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

As a specific example of the organic cation-anion salt, a compound comprising a combination of the above cation component and anion component is appropriately selected and used.
For example, 1-butylpyridinium tetrafluoroborate, 1-butylpyridinium hexafluorophosphate, 1-butyl-3-methylpyridinium tetrafluoroborate, 1-butyl-3-methylpyridinium trifluoromethanesulfonate, 1-butyl-3-methylpyridinium Bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylpyridinium bis(pentafluoroethanesulfonyl)imide, 1-hexylpyridinium tetrafluoroborate, 2-methyl-1-pyrroline tetrafluoroborate, 1-ethyl-2 -Phenylindole tetrafluoroborate, 1,2-dimethylindole tetrafluoroborate, 1-ethylcarbazole tetrafluoroborate, 1-ethyl-3-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 perfluorobutane Sulfonate, 1-ethyl-3-methylimidazolium dicyanamide, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylimidazolium bis(pentafluoroethanesulfonyl)imide, 1 -Ethyl-3-methylimidazolium tris(trifluoromethanesulfonyl)methide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazo Lithium trifluoroacetate, 1-butyl-3-methylimidazolium heptafluorobutyrate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium perfluorobutanesulfonate, 1-butyl-3 -Methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-hexyl-3-methylimidazolium bromide, 1-hexyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium tetrafluoroborate, 1-hexyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-3 -Methylimidazolium trifluoromethanesulfonate, 1-octyl-3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-2,3-dimethylimidazolium tetrafluoroborate, 1,2-dimethyl-3-propylimidazolium bis(trifluoromethanesulfonyl)imide, 1-methylpyrazolium tetrafluoroborate, 3-methylpyrazolium tetrafluoroborate, tetrahexyl ammonium bis(trifluoromethanesulfonyl)imide, Diallyldimethylammonium tetrafluoroborate, diallyldimethylammonium trifluoromethanesulfonate, diallyldimethylammonium bis(trifluoromethanesulfonyl)imide, diallyldimethylammonium bis(pentafluoroethanesulfonyl)imide, N,N-diethyl-N-methyl-N-( 2-methoxyethyl)ammonium tetrafluoroborate, N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium trifluoromethanesulfonate, N,N-diethyl-N-methyl-N-(2-methoxyethyl) ) Ammonium bis(trifluoromethanesulfonyl)imide, N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(pentafluoroethanesulfonyl)imide, glycidyltrimethylammonium trifluoromethanesulfonate, glycidyltrimethylammonium bis( Trifluoromethanesulfonyl)imide, glycidyltrimethylammonium bis(pentafluoroethanesulfonyl)imide, 1-butylpyridinium (trifluoromethanesulfonyl)trifluoroacetamide, 1-butyl-3-methylpyridinium (trifluoromethanesulfonyl)trifluoroacetamide, 1- Ethyl-3-methylimidazolium (trifluoromethanesulfonyl)trifluoroacetamide, N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium (trifluoromethanesulfonyl)trifluoroacetamide, diallyldimethylammonium (trifluoromethane Sulfonyl)trifluoroacetamide, glycidyltrimethylammonium (trifluoromethanesulfonyl)trifluoroacetamide, N,N-dimethyl-N-ethyl-N-pro Pyrammonium bis(trifluoromethanesulfonyl)imide, N,N-dimethyl-N-ethyl-N-butylammonium bis(trifluoromethanesulfonyl)imide, N,N-dimethyl-N-ethyl-N-pentylammonium bis(trifluoromethane Sulfonyl)imide, N,N-dimethyl-N-ethyl-N-hexylammonium bis(trifluoromethanesulfonyl)imide, N,N-dimethyl-N-ethyl-N-heptylammonium bis(trifluoromethanesulfonyl)imide, N , N-dimethyl-N-ethyl-N-nonylammonium bis(trifluoromethanesulfonyl)imide, N,N-dimethyl-N,N-dipropylammonium bis(trifluoromethanesulfonyl)imide, N,N-dimethyl-N- Propyl-N-butylammonium bis(trifluoromethanesulfonyl)imide, N,N-dimethyl-N-propyl-N-pentylammonium bis(trifluoromethanesulfonyl)imide, N,N-dimethyl-N-propyl-N-hexylammonium Bis(trifluoromethanesulfonyl)imide, N,N-dimethyl-N-propyl-N-heptylammonium bis(trifluoromethanesulfonyl)imide, N,N-dimethyl-N-butyl-N-hexylammonium bis(trifluoromethanesulfonyl) Imido, N,N-dimethyl-N-butyl-N-heptylammonium bis(trifluoromethanesulfonyl)imide, N,N-dimethyl-N-pentyl-N-hexylammonium bis(trifluoromethanesulfonyl)imide, N,N- Dimethyl-N,N-dihexyl ammonium bis(trifluoromethanesulfonyl)imide, trimethylheptyl ammonium bis(trifluoromethanesulfonyl)imide, N,N-diethyl-N-methyl-N-propylammonium bis(trifluoromethanesulfonyl)imide, N , N-diethyl-N-methyl-N-pentylammonium bis(trifluoromethanesulfonyl)imide, N,N-diethyl-N-methyl-N-heptylammonium bis(trifluoromethanesulfonyl)imide, N,N-diethyl-N -Propyl-N-pentylammonium bis(trifluoromethanesulfonyl)imide, triethylpropylammonium bis(trifluoromethanesulfonyl)imide, triethylpentylammonium bis (Trifluoromethanesulfonyl)imide, triethylheptyl ammonium bis(trifluoromethanesulfonyl)imide, N,N-dipropyl-N-methyl-N-ethylammonium bis(trifluoromethanesulfonyl)imide, N,N-dipropyl-N-methyl- N-pentylammonium bis(trifluoromethanesulfonyl)imide, N,N-dipropyl-N-butyl-N-hexylammonium bis(trifluoromethanesulfonyl)imide, N,N-dipropyl-N,N-dihexylammonium bis(trifluoro) Rmethanesulfonyl)imide, N,N-dibutyl-N-methyl-N-pentylammonium bis(trifluoromethanesulfonyl)imide, N,N-dibutyl-N-methyl-N-hexylammonium bis(trifluoromethanesulfonyl)imide, tri Octylmethylammonium bis(trifluoromethanesulfonyl)imide, N-methyl-N-ethyl-N-propyl-N-pentylammonium bis(trifluoromethanesulfonyl)imide, 1-butyl-3methylpyridin-1-ium trifluoromethanesulfon Examples include narts. As these commercially available products, for example, "CIL-314" (manufactured by Nippon Carlit Co., Ltd.), "ILA2-1" (manufactured by Koei Chemical Co., Ltd.) and the like can be used.
Further, for example, tetramethylammonium bis(trifluoromethanesulfonyl)imide, trimethylethylammonium bis(trifluoromethanesulfonyl)imide, trimethylbutylammonium bis(trifluoromethanesulfonyl)imide, trimethylpentylammonium bis(trifluoromethanesulfonyl)imide, trimethylheptyl Ammonium bis(trifluoromethanesulfonyl)imide, trimethyloctyl ammonium bis(trifluoromethanesulfonyl)imide, tetraethylammonium bis(trifluoromethanesulfonyl)imide, triethylbutylammonium bis(trifluoromethanesulfonyl)imide, tetrabutylammonium bis(trifluoromethanesulfonyl) Imide, tetrahexyl ammonium bis(trifluoromethanesulfonyl)imide, and the like.
Further, for example, 1-dimethylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-ethylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-propylpyrrolidinium bis(trifluoromethane) Sulfonyl)imide, 1-methyl-1-butylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-pentylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-hexylpyrrolidinium Bis(trifluoromethanesulfonyl)imide, 1-methyl-1-heptylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-ethyl-1-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-ethyl-1 -Butylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-ethyl-1-pentylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-ethyl-1-hexylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-ethyl-1-heptylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1,1-dipropylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-propyl-1-butylpyrrolidinium bis(trifluoromethane Sulfonyl)imide, 1,1-dibutylpyrrolidinium bis(trifluoromethanesulfonyl)imide, 1-propylpiperidinium bis(trifluoromethanesulfonyl)imide, 1-pentylpiperidinium bis(trifluoromethanesulfonyl)imide, 1, 1-dimethylpiperidinium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-ethylpiperidinium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-propylpiperidinium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-butylpiperidinium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-pentylpiperidinium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-hexylpiperidinium bis(trifluoromethane Sulfonyl)imide, 1-methyl-1-heptylpiperidinium bis(trifluoromethanesulfonyl)imide, 1-ethyl-1-propylpiperidinium bis(trifluoromethanesulfonyl)imide, 1- Ethyl-1-butylpiperidinium bis(trifluoromethanesulfonyl)imide, 1-ethyl-1-pentylpiperidinium bis(trifluoromethanesulfonyl)imide, 1-ethyl-1-hexylpiperidinium bis(trifluoromethanesulfonyl) Imido, 1-ethyl-1-heptylpiperidinium bis(trifluoromethanesulfonyl)imide, 1,1-dipropylpiperidinium bis(trifluoromethanesulfonyl)imide, 1-propyl-1-butylpiperidinium bis(trifluoro) Methanesulfonyl)imide, 1,1-dibutylpiperidinium bis(trifluoromethanesulfonyl)imide, 1,1-dimethylpyrrolidinium bis(pentafluoroethanesulfonyl)imide, 1-methyl-1-ethylpyrrolidinium bis( Pentafluoroethanesulfonyl)imide, 1-methyl-1-propylpyrrolidinium bis(pentafluoroethanesulfonyl)imide, 1-methyl-1-butylpyrrolidinium bis(pentafluoroethanesulfonyl)imide, 1-methyl-1 -Pentylpyrrolidinium bis(pentafluoroethanesulfonyl)imide, 1-methyl-1-hexylpyrrolidinium bis(pentafluoroethanesulfonyl)imide, 1-methyl-1-heptylpyrrolidinium bis(pentafluoroethanesulfonyl) ) Imido, 1-ethyl-1-propylpyrrolidinium bis(pentafluoroethanesulfonyl)imide, 1-ethyl-1-butylpyrrolidinium bis(pentafluoroethanesulfonyl)imide, 1-ethyl-1-pentylpyrrolidinide Bis(pentafluoroethanesulfonyl)imide, 1-ethyl-1-hexylpyrrolidinium bis(pentafluoroethanesulfonyl)imide, 1-ethyl-1-heptylpyrrolidinium bis(pentafluoroethanesulfonyl)imide, 1 ,1-dipropylpyrrolidinium bis(pentafluoroethanesulfonyl)imide, 1-propyl-1-butylpyrrolidinium bis(pentafluoroethanesulfonyl)imide, 1,1-dibutylpyrrolidinium bis(pentafluoroethanesulfonyl) ) Imido, 1-propylpiperidinium bis(pentafluoroethanesulfonyl)imide, 1-pentylpiperidinium bis(pentafluoroethanesulfonyl)imide, 1,1-dimethylpiperidinium bis(pentafluoroethanesulfonyl)imide Amide, 1-methyl-1-ethylpiperidinium bis(pentafluoroethanesulfonyl)imide, 1-methyl-1-propylpiperidinium bis(pentafluoroethanesulfonyl)imide, 1-methyl-1-butylpiperidinium Bis(pentafluoroethanesulfonyl)imide, 1-methyl-1-pentylpiperidinium bis(pentafluoroethanesulfonyl)imide, 1-methyl-1-hexylpiperidinium bis(pentafluoroethanesulfonyl)imide, 1-methyl -1 heptylpiperidinium bis(pentafluoroethanesulfonyl)imide, 1-ethyl-1-propylpiperidinium bis(pentafluoroethanesulfonyl)imide, 1-ethyl-1-heptylpiperidinium bis(pentafluoroethane) Sulfonyl)imide, 1-ethyl-1-pentylpiperidinium bis(pentafluoroethanesulfonyl)imide, 1-ethyl-1-hexylpiperidinium bis(pentafluoroethanesulponyl)imide, 1-ethyl-1- Heptylpiperidinium bis(pentafluoroethanesulfonyl)imide, 1-propyl-1-butylpiperidinium bis(pentafluoroethanesulfonyl)imide, 1,1-dipropylpiperidinium bis(pentafluoroethanesulfonyl)imide , 1,1-dibutylpiperidinium bis(pentafluoroethanesulfonyl)imide and the like.
Further, instead of the cation component of the above compound, trimethylsulfonium cation, triethylsulfonium cation, tributylsulfonium cation, trihexylsulfonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, dimethyldecylsulfonium cation, tetramethylphosphonium cation, tetraethylphosphonium cation Examples thereof include compounds using a cation, a tetrabutylphosphonium cation, and a tetrahexylphosphonium cation.
Further, instead of the above bis(trifluoromethanesulfonyl)imide, bis(pentafluorosulfonyl)imide, bis(heptafluoropropanesulfonyl)imide, bis(nonafluorobutanesulfonyl)imide, trifluoromethanesulfonyl nonafluorobutanesulfonylimide, Examples include compounds using heptafluoropropanesulfonyl trifluoromethanesulfonylimide, pentafluoroethanesulfonylnonafluorobutanesulfonylimide, cyclo-hexafluoropropane-1,3-bis(sulfonyl)imide anion, and the like.

As the ionic compound (D), in addition to the above-mentioned alkali metal salts and organic cation-anion salts, inorganic salts such as ammonium chloride, aluminum chloride, copper chloride, ferrous chloride, ferric chloride and ammonium sulfate. Is mentioned. These ionic compounds (D) can be used alone or in combination.

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

The pressure-sensitive adhesive composition of the present invention may contain a polyether compound (E) having a reactive silyl group. The polyether compound (E) is preferable in that the reworkability can be improved. As the polyether compound (E), for example, those disclosed in JP 2010-275522A can be used.

The polyether compound (E) having a reactive silyl group has a polyether skeleton and has at least one terminal represented by the following general formula (1): —SiR _a M _3-a.
(In the formula, R is a monovalent organic group having 1 to 20 carbon atoms which may have a substituent, M is a hydroxyl group or a hydrolyzable group, and a is an integer of 0 to 2. However, when there are a plurality of Rs, the plurality of Rs may be the same as or different from each other, and when there are a plurality of Ms, the plurality of Ms may be the same as or different from each other. It has a reactive silyl group represented.

As the polyether compound (E) having a reactive silyl group,
Formula _{(2): R a M 3} -a Si-X-Y- (AO) n -Z
(In the formula, R is a monovalent organic group having 1 to 20 carbon atoms which may have a substituent, M is a hydroxyl group or a hydrolyzable group, and a is an integer of 0 to 2. However, when there are a plurality of Rs, the plurality of Rs may be the same or different from each other, and when there are a plurality of Ms, the plurality of Ms may be the same or different from each other. Represents a linear or branched oxyalkylene group having 1 to 10 carbon atoms, n is 1 to 1700, and represents the average number of moles of addition of the oxyalkylene group, and X represents a linear chain having 1 to 20 carbon atoms or Represents a branched alkylene group, and Y represents an ether bond, an ester bond, a urethane bond, or a carbonate bond.
Z is a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms,
Formula ^{(2A): - Y 1 -X} -SiR a M 3-a
(In the formula, R, M and X are the same as the above. Y ¹ represents a single bond, a -CO- bond, a -CONH- bond or a -COO- bond.), or
Formula _{(2B): - Q {-} (OA) n -Y-X-SiR a M 3-a} m
(In the formula, R, M, X and Y are the same as the above. OA is the same as the above AO and n is the same as the above. Q is a divalent or higher valent hydrocarbon group having 1 to 10 carbon atoms. , M are the same as the valence of the hydrocarbon group.). ).

Specific examples of the polyether compound (E) having a reactive silyl group include MS polymers S203, S303, S810 manufactured by Kaneka; SILYL EST250, EST280; SAT10, SAT200, SAT220, SAT350, SAT400, manufactured by Asahi Glass Co., Ltd. EXCESTAR S2410, S2420, S3430 and the like.

The proportion of the polyether compound (E) in the pressure-sensitive adhesive composition of the present invention is preferably 0.001 to 10 parts by weight with respect to 100 parts by weight of the (meth)acrylic polymer (A). When the amount of the polyether compound (E) is less than 0.001 part by weight, the effect of improving reworkability may not be sufficient. The polyether compound (E) is preferably 0.01 part by weight or more, and more preferably 0.1 part by weight or more. On the other hand, if the amount of the polyether compound (E) is more than 10 parts by weight, it is not preferable in terms of durability. The polyether compound (E) is preferably 5 parts by weight or less, and more preferably 2 parts by weight or less. The ratio of the polyether compound (E) can be set to a preferable range by adopting the upper limit value or the lower limit value.

Further, the pressure-sensitive adhesive composition of the present invention may contain other known additives, for example, polyether compounds of polyalkylene glycol such as polypropylene glycol, colorants, powders such as pigments, dyes, Surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, softeners, antioxidants, antioxidants, light stabilizers, UV absorbers, polymerization inhibitors, inorganic or organic fillers, metals Powders, particles, foils and the like can be appropriately added depending on the intended use. Further, a redox system to which a reducing agent is added may be adopted within a controllable range. These additives are preferably used in an amount of 5 parts by weight or less, more preferably 3 parts by weight or less, and further preferably 1 part by weight or less with respect to 100 parts by weight of the (meth)acrylic polymer (A).

The pressure-sensitive adhesive composition is used to form a pressure-sensitive adhesive layer. In forming the pressure-sensitive adhesive layer, it is necessary to carefully consider the effects of the crosslinking treatment temperature and the crosslinking treatment time while adjusting the addition amount of the entire crosslinking agent. preferable.

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.

In addition, the crosslinking treatment may be performed at the temperature during the drying step of the pressure-sensitive adhesive layer, or may be performed by separately providing a crosslinking treatment step after the drying step.

The cross-linking 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.

The above-mentioned crosslinking is controlled so that the gel fraction of the pressure-sensitive adhesive layer is usually 50% by weight or more, but the gel fraction of the pressure-sensitive adhesive layer is more than 70% by weight from the viewpoint of high temperature durability. Is preferably controlled so that The gel fraction is preferably 75% by weight, more preferably 80% by weight or more. On the other hand, if the gel fraction becomes too large, peeling easily occurs in the durability test. Therefore, the gel fraction is preferably 98% by weight or less, and more preferably 95% by weight or less.

The pressure-sensitive adhesive layer-carrying optical member such as the pressure-sensitive adhesive layer-carrying optical film of the present invention has a pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive composition on at least one surface of the optical film.

As a method for forming a pressure-sensitive adhesive layer, for example, a method in which the pressure-sensitive adhesive composition is applied to a release-treated separator or the like, and a polymerization solvent or the like is dried and removed to form a pressure-sensitive adhesive layer, and then transferred to an optical film, or It is prepared by a method such as applying the pressure-sensitive adhesive composition to an optical film, drying and removing a polymerization solvent and the like to form a pressure-sensitive adhesive layer on the optical film. When applying the pressure-sensitive adhesive, one or more solvents other than the polymerization solvent may be newly added as appropriate.

A silicone release liner is preferably used as the release-treated separator. In the step of forming the pressure-sensitive adhesive layer by applying the adhesive composition of the present invention on such a liner, and drying the pressure-sensitive adhesive layer, as a method for drying the pressure-sensitive adhesive, an appropriate method is appropriately adopted depending on the purpose. obtain. Preferably, a method of heating and drying the above coating film is used. The heating and 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 in the above range, a pressure-sensitive adhesive having excellent pressure-sensitive adhesive properties can be obtained.

As the drying time, an appropriate time can be appropriately adopted. 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 on the surface of the optical film after forming an anchor layer or after performing various types of easy-adhesion treatment such as corona treatment and plasma treatment. Further, the surface of the pressure-sensitive adhesive layer may be subjected to easy adhesion treatment.

Various methods are used for forming the pressure-sensitive adhesive layer. Specifically, for example, 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 of the method include an extrusion coating method.

The thickness of the pressure-sensitive adhesive layer is not particularly limited and is, for example, about 1 to 100 μm. The thickness is preferably 2 to 50 μm, more preferably 2 to 40 μm, and further preferably 5 to 35 μm.

When the pressure-sensitive adhesive layer is exposed, the pressure-sensitive adhesive layer may be protected by a release-treated sheet (separator) until practical use.

As a constituent material of the separator, for example, polyethylene, polypropylene, polyethylene terephthalate, a plastic film such as a polyester film, a porous material such as paper, cloth, non-woven fabric, a net, a foamed sheet, a metal foil, and a laminated body thereof are appropriately used. A thin film can be used, but a plastic film is preferably used because of its excellent surface smoothness.

The plastic film is not particularly limited as long as it is a film capable of protecting the pressure-sensitive adhesive layer, and examples thereof include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film and vinyl chloride. Examples thereof include polymer films, polyethylene terephthalate films, polybutylene terephthalate films, polyurethane films, ethylene-vinyl acetate copolymer films and the like.

The thickness of the separator is usually 5 to 200 μm, preferably about 5 to 100 μm. In the separator, if necessary, a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, release and antifouling treatment with silica powder or the like, coating type, kneading type, vapor deposition type It is also possible to perform antistatic treatment such as. Particularly, by appropriately performing a peeling treatment such as a silicone treatment, a long-chain alkyl treatment, or a fluorine treatment on the surface of the separator, the peelability from the pressure-sensitive adhesive layer can be further enhanced.

The release-treated sheet used in the production of the pressure-sensitive adhesive layer-carrying optical film can be used as it is as a separator for the pressure-sensitive adhesive layer-carrying optical film, and the process can be simplified.

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

The polarizer is not particularly limited, and various kinds can be used. Examples of the polarizer include hydrophilic polymer films such as polyvinyl alcohol film, partially formalized polyvinyl alcohol film, and ethylene/vinyl acetate copolymer partially saponified film, and dichroism of iodine or dichroic dye. Examples include polyene-oriented films such as those obtained by adsorbing a substance and uniaxially stretched, polyvinyl alcohol dehydrated products, polyvinyl chloride dehydrochlorinated products, and the like. Among these, a polarizer made of a polyvinyl alcohol film and a dichroic material such as iodine is preferable. The thickness of these polarizers is not particularly limited, but is generally about 80 μm or less.

A polarizer obtained by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretching can be produced, for example, by dyeing a polyvinyl alcohol-based film by immersing it in an aqueous solution of iodine and stretching it to 3 to 7 times its original length. it can. 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 with water before dyeing. By washing the polyvinyl alcohol-based film with water, it is possible to wash the stains and anti-blocking agent on the surface of the polyvinyl alcohol-based film, and by swelling the polyvinyl alcohol-based film, the effect of preventing unevenness such as unevenness of dyeing is also exerted. is there. Stretching may be performed after dyeing with iodine, stretching while dyeing, or stretching and then dyeing with iodine. Stretching can be performed in an aqueous solution of boric acid or potassium iodide or in a water bath.

A thin polarizer having a thickness of 10 μm or less can be used as the polarizer. From the viewpoint of thinning, the thickness is preferably 1 to 7 μm. It is preferable that such a thin polarizer has little thickness unevenness, excellent visibility, and excellent durability due to small dimensional change, and that the thickness of the polarizing film can be reduced.

As the thin polarizer, typically, JP-A-51-0696644, JP-A-2000-338329, WO2010/100917, the specification of PCT/JP2010/001460, or Japanese Patent Application No. 2010- Examples include thin polarizing films described in Japanese Patent No. 269002 and Japanese Patent Application No. 2010-263692. These thin polarizing films can be obtained by a manufacturing 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 dyeing step. According to this production method, even if the PVA-based resin layer is thin, it can be stretched without trouble such as breakage due to stretching because it is supported by the stretching resin base material.

As the thin polarizing film, among manufacturing methods including a step of stretching in the state of a laminate and a step of dyeing, WO2010/100917 pamphlet, PCT/ Those obtained by a method including a step of stretching in an aqueous boric acid solution as described in JP 2010/001460, or Japanese Patent Application Nos. 2010-269002 and 2010-263692 are preferable, and particularly preferable. Those obtained by a production method including a step of supplementary in-air stretching before stretching in a boric acid aqueous solution described in Japanese Patent Application No. 2010-269002 and Japanese Patent Application No. 2010-263692 are preferable.

As a material forming the transparent protective film, for example, a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropic property, etc. is used. Specific examples of such a thermoplastic resin include cellulose resins such as triacetyl cellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, and cyclic resins. Examples thereof include polyolefin resins (norbornene-based resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. A transparent protective film is attached to one side of the polarizer with an adhesive layer, while a transparent protective film is attached to the other side as a (meth)acrylic type, urethane type, acrylic urethane type, epoxy type, or silicone type. A thermosetting resin such as a system or an ultraviolet curable resin can be used. One or more kinds of any appropriate additive may be contained in the transparent protective film. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a 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, further preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. .. When the content of the thermoplastic resin in the transparent protective film is 50% by weight or less, the high transparency originally possessed by the thermoplastic resin may not be sufficiently exhibited.

The adhesive used for bonding the polarizer and the transparent protective film is not particularly limited as long as it is optically transparent, and various types of water-based, solvent-based, hot-melt-based, radical-curable, and cation-curable types are used. However, a water-based adhesive or a radical curable adhesive is preferable.

Further, as the 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 a wavelength plate such as 1/2 or 1/4), a visual compensation film, and a brightness enhancement film. Examples of the optical layer that can be used are described below. These may be used alone as an optical film, or may be laminated on the polarizing film in practical use to use one layer or two or more layers.

The optical film obtained by laminating the optical layer on the polarizing film can be formed by a method of sequentially laminating separately in the manufacturing process of a liquid crystal display device or the like. It is excellent in stability and assembling work and has an advantage that the manufacturing process of liquid crystal display devices can be improved. Appropriate adhesion means such as an adhesive layer may be used for lamination. When the polarizing film and other optical layers are bonded, their optical axes can be arranged at appropriate angles according to the intended retardation characteristics and the like.

The pressure-sensitive adhesive layer-carrying optical film of the present invention can be preferably used for forming various image display devices such as liquid crystal display devices. The liquid crystal display device can be formed in a conventional manner. That is, a liquid crystal display device is generally formed by appropriately assembling a display panel such as a liquid crystal cell and an optical film with an adhesive layer, and optionally a component such as an illumination system and incorporating a drive circuit, The present invention is not particularly limited except that the pressure-sensitive adhesive layer-carrying optical film according to the present invention is used, and the conventional method can be applied. The liquid crystal cell may be of any type such as TN type, STN type, π type, VA type and IPS type.

It is possible to form a liquid crystal display device in which an optical film with an adhesive layer is arranged on one side or both sides of a display panel such as a liquid crystal cell, or an appropriate liquid crystal display device such as one using a backlight or a reflector for an illumination system. . In this case, the pressure-sensitive adhesive layer-carrying optical film according to the present invention can be installed on one side or both sides of a display panel such as a liquid crystal cell. When optical films are provided on both sides, they may be the same or different. Furthermore, when forming a liquid crystal display device, for example, a diffusion layer, an anti-glare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusion sheet, a back light, and other appropriate components are provided at appropriate positions in one layer or Two or more layers can be arranged.

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

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

<Creation of polarizing film>
A polyvinyl alcohol film having a thickness of 80 μm was stretched up to 3 times while being dyed in a 0.3% concentration iodine solution at 30° C. for 1 minute between rolls having different speed ratios. Then, the film was stretched to a total stretching ratio of 6 times while being immersed in an aqueous solution containing boric acid having a concentration of 4% and potassium iodide having a concentration of 10% at 60° C. for 0.5 minutes. Next, the resultant was washed by immersing it in an aqueous solution containing potassium iodide having a concentration of 1.5% at 30° C. for 10 seconds, and then dried at 50° C. for 4 minutes to obtain a polarizer having a thickness of 30 μm. A saponified triacetyl cellulose film having a thickness of 80 μm was attached to both surfaces of the polarizer with a polyvinyl alcohol-based adhesive to form a polarizing film.

Example 1
(Preparation of acrylic polymer (A1))
77 parts of butyl acrylate, 16 parts of phenoxyethyl acrylate, 6 parts of N-vinyl-2-pyrrolidone, and 4-hydroxybutyl acrylate 1 were placed in a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a condenser. A monomer mixture containing 1 part was charged. Further, with respect to 100 parts of the monomer mixture (solid content), 0.1 part of 2,2′-azobisisobutyronitrile as a polymerization initiator was charged together 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., and an acrylic polymer (A1 having a weight average molecular weight (Mw) of 1.8 million and Mw/Mn=4.1 (A1 ) Solution was prepared.

(Preparation of adhesive composition)
To 100 parts of the solid content of the solution of the acrylic polymer (A1) obtained in Production Example 1, 0.2 parts of an isocyanate crosslinking agent (Takenate D160N, trimethylolpropane hexamethylene diisocyanate manufactured by Mitsui Chemicals, Inc.), benzoylper 0.2 parts of oxide (NIPPER BMT manufactured by NOF CORPORATION) and 0.2 part of γ-glycidoxypropylmethoxysilane (KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed to prepare an acrylic pressure-sensitive adhesive composition. Was prepared.

(Preparation of polarizing film with adhesive layer)
Then, the solution of the acrylic pressure-sensitive adhesive composition was applied to one side of a polyethylene terephthalate film (separator film: manufactured by Mitsubishi Kagaku Polyester Film Co., Ltd., MRF38) treated with a silicone-based release agent to form a dried pressure-sensitive adhesive layer. It was applied to a thickness of 23 μm and dried at 155° C. for 1 minute to form an adhesive layer on the surface of the separator film. Then, the pressure-sensitive adhesive layer formed on the separator film was transferred to the above-prepared polarizing film to prepare a pressure-sensitive adhesive layer-attached polarizing film.

Examples 2-15, Comparative Examples 1-8
In Example 1, as shown in Table 1, the types of monomers used in the preparation of the acrylic polymer (A), the use ratios thereof were changed, and the production conditions were controlled. A solution of an acrylic polymer having an average molecular weight, Mw/Mn) was prepared.

Further, as shown in Table 1, the type or amount of the cross-linking agent (B) and the amount of the silane coupling agent (C) used were changed for each of the obtained acrylic polymer solutions. A solution of the acrylic pressure-sensitive adhesive composition was prepared in the same manner as in Example 1. Further, a polarizing plate with an adhesive layer was produced in the same manner as in Example 1 using the solution of the acrylic adhesive composition. In addition, in Examples 12 to 14 and Comparative Example 4, a solution of an acrylic polymer in which the ionic compound (D) was blended at the ratio shown in Table 1 was prepared.

The following evaluations were performed on the pressure-sensitive adhesive layer-attached polarizing films obtained in the above Examples and Comparative Examples. The evaluation results are shown in Tables 1 and 2. The surface resistance value was measured only for the pressure-sensitive adhesive layer-attached polarizing films obtained in Examples 12 to 14 and Comparative Example 4.

<Measurement of gel fraction>
Approximately 0.1 g of the pressure-sensitive adhesive layer was taken and wrapped in a fluororesin film (TEMISH NTF-1122, manufactured by Nitto Denko Corporation) (weight: Wa), the weight of which was measured in advance, and the pressure-sensitive adhesive was bound so as not to leak, and a measurement sample And The sample was weighed (weight: Wb), put in a bottle, 40 cc of ethyl acetate was added, and the sample was allowed to stand for 7 days. Then, the measurement sample was taken out, and the measurement sample was dried at 130° C. for 2 hours. The weight (Wc) of the dried sample was measured, and the gel fraction was calculated by the following formula.

<Durability test with glass>
A polarizing film with an adhesive layer cut into a 37-inch size was used as a sample. The sample was attached to a 0.7 mm-thick non-alkali glass (Corning, EG-XG) using a laminator. Then, the sample was autoclaved at 50° C. and 0.5 MPa for 15 minutes to completely adhere the sample to acrylic-free glass. The sample thus treated was treated in an atmosphere of 95° C. for 500 hours (heating test), and also in an atmosphere of 60° C./95% RH for 500 hours (humidification test). After the environment of 85° C. and −40° C. was subjected to 300 cycles of 1 hour for 1 hour (heat shock test), the appearance between the polarizing plate and the glass was visually evaluated according to the following criteria.
(Evaluation criteria)
⊚: No change in appearance such as foaming or peeling.
◯: Peeling or foaming at the edge, although slightly, but practically no problem.
Δ: There is peeling or foaming at the end, but the range is hidden by the bezel, and there is no practical problem.
X: Peeling was noticeable at the edges, which was a problem in practical use.

<Durability test with ITO glass>
In the <Durability test on glass>, the non-alkali glass used as the adherend on which a crystalline ITO or amorphous ITO layer was formed was used as an adherend of <Durability test on ITO glass>. did. As described above, the durability test on the ITO glass was performed in the same procedure as the <Durability test on glass> except that the adherend was changed and the sample was bonded to the ITO layer. The ITO layer was formed by sputtering. Regarding the composition of ITO, the crystalline ITO had a Sn ratio of 10% by weight, and the amorphous ITO had a Sn ratio of 3% by weight, and a heating process was carried out at 140° C.×60 minutes before bonding the samples. The Sn ratio of ITO was calculated from the weight of Sn atoms/(weight of Sn atoms+weight of In atoms).

<Metal corrosion resistance>
A polarizing film with an adhesive layer cut into 8 mm×8 mm was used as a sample. A conductive film (trade name: Elekrista (P400L), manufactured by Nitto Denko Co., Ltd.) having an ITO layer formed on the film surface was cut into 15 mm×15 mm, and the sample was attached to the center of the conductive film. After being combined, the sample was autoclaved at 50° C. and 5 atm for 15 minutes to obtain a corrosion resistance measurement sample. The resistance value of the obtained measurement sample was measured using the measuring device described later, and this was defined as the "initial resistance value".
After that, the measurement sample was put in an environment of 60° C./90% RH for 500 hours, and the resistance value was measured, and the result was taken as the “resistance value after wet heat”. The resistance value was measured using HL5500PC manufactured by Accent Optical Technologies. From the "initial resistance value" and "resistance value after moist heat" measured as described above, "resistance value change" was calculated by the following formula.

<Display unevenness>
Two pieces of polarizing film with an adhesive layer cut into a size of length 420 mm×width 320 mm were prepared as samples. This sample was laminated on both surfaces of a 0.07 mm-thick non-alkali glass plate with a laminator so as to form a crossed Nicols. Then, autoclave treatment was performed at 50° C. and 5 atm for 15 minutes to obtain a secondary sample (initial). Then, the secondary sample was treated under the condition of 90° C. for 24 hours (after heating). The secondary sample after initial heating and after heating was placed on a backlight of 10,000 candela, and light leakage was visually evaluated according to the following criteria.
(Evaluation criteria)
⊚: No corner unevenness was observed and there was no practical problem.
◯: There is slight corner unevenness, but since it does not appear in the display area, there is no practical problem.
Δ: Corner unevenness occurs and appears slightly in the display area, but there is no practical problem.
X: Corner unevenness is generated and is tightly displayed in the display area, which is a problem in practical use.

<Conductivity: Surface resistance value (Ω/□)>
After the separator film of the polarizing film with the pressure-sensitive adhesive layer was peeled off, the surface resistance value (initial) of the pressure-sensitive adhesive surface was measured. In addition, after putting the polarizing film with an adhesive layer in an environment of 60° C./95% RH for 500 hours and then drying it at 40° C. for 1 hour, after peeling the separator film, the surface resistance value of the adhesive surface (wet heat After) was measured. The measurement was performed using MCP-HT450 manufactured by Mitsubishi Chemical Analytech.

<Humidification cloudiness>
The polarizing film with the pressure-sensitive adhesive layer was cut into a size of 50 mm×50 mm and attached to glass. Furthermore, a PET film (Diafoil T100-25B, manufactured by Mitsubishi Plastics Co., Ltd.) having a thickness of 25 μm was cut into a size of 50 mm×50 mm, and stuck on the upper surface of the polarizing film to obtain a measurement sample. After the measurement sample was put in an environment of 60° C./95% RH for 250 hours, it was taken out at room temperature and the haze value after 10 minutes was measured. The haze value was measured using a haze meter HM150 manufactured by Murakami Color Research Laboratory.

In Table 1, the monomers used to prepare the acrylic polymer (A) are
BA: butyl acrylate,
PEA: phenoxyethyl acrylate,
NVP: N-vinyl-pyrrolidone,
NVC: N-vinyl-ε-caprolactam,
HBA: 4-hydroxybutyl acrylate,
HEA: 2-hydroxyethyl acrylate,
AA: acrylic acid,
Indicates.
In the cross-linking agent (B), "isocyanate-based""D160N" is Takenate D160N (adduct of hexamethylene diisocyanate of trimethylolpropane) manufactured by Mitsui Chemicals, and "C/L" is Coronate L manufactured by Nippon Polyurethane Industry Co., Ltd. (Adduct of trimethylolpropane tolylene diisocyanate)
"Peroxide type" is benzoyl peroxide (NIPPER BMT manufactured by NOF CORPORATION)
“Silane coupling agent (C)” is KBM403: KBM403 manufactured by Shin-Etsu Chemical Co., Ltd.
"Ionic compound (D)" is
Li-TFSI: bis(trifluoromethanesulfonyl)imide lithium manufactured by Mitsubishi Materials;
EMP-TFSI: 1-ethyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide manufactured by Mitsubishi Materials Corporation.

Claims (12)

33% by weight or more of alkyl (meth)acrylate (a1) as a monomer unit,
Aromatic ring-containing (meth)acrylate (a2) 3 to 25% by weight,
N-vinyl group-containing lactam monomer (a3) 5 to 35% by weight,
2% by weight or less of a carboxyl group-containing monomer (a5), and
The (meth)acrylic polymer (A) containing 0.01 to 7% by weight of the hydroxyl group-containing monomer (a4) and the crosslinking agent (B) are added to 100 parts by weight of the (meth)acrylic polymer (A). Te, a pressure-sensitive adhesive layer for an optical film which is formed by light optical film pressure-sensitive adhesive composition you containing 0.01 to 3 parts by weight,
A pressure-sensitive adhesive layer for an optical film, which has a gel fraction of more than 70% by weight . The pressure-sensitive adhesive layer for an optical film according to claim 1, wherein the hydroxyl group-containing monomer (a4) is 4-hydroxybutyl (meth)acrylate. The pressure-sensitive adhesive layer for an optical film according to claim 1 or 2 , wherein the crosslinking agent (B) contains at least one selected from an isocyanate crosslinking agent and a peroxide crosslinking agent. The pressure-sensitive adhesive layer for an optical film according to claim 3, wherein the isocyanate-based crosslinking agent contains an aliphatic polyisocyanate-based compound. Further, the optical film pressure-sensitive adhesive layer according to any one of claims 1 to 4, characterized in that it contains a silane coupling agent (C). The adhesive for optical films according to claim 5, wherein the silane coupling agent (C) is contained in an amount of 0.001 to 5 parts by weight with respect to 100 parts by weight of the (meth)acrylic polymer (A). Agent layer . Further, the optical film pressure-sensitive adhesive layer according to any one of claims 1 to 6, characterized in that it contains an ionic compound (D). The pressure-sensitive adhesive layer for an optical film according to claim 7, wherein the ionic compound (D) is an alkali metal salt and/or an organic cation-anion salt. The pressure-sensitive adhesive layer for an optical film according to claim 7, wherein the ionic compound (D) contains a fluoro group-containing anion. The ionic compound (D), according to any one of claims 7-9 to the (meth) acrylic polymer (A) 100 parts by weight of, characterized in that it contains 0.05 to 10 parts by weight Adhesive layer for optical film of. An optical film with a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer for an optical film according to any one of claims 1 to 10 is formed on at least one side of the optical film. An image display device comprising at least one optical film with an adhesive layer according to claim 11 .