TW201903090A - Polarizing film with adhesive layer, and image display device - Google Patents

Abstract

The purpose of the present invention is to provide a polarizing film with an adhesive layer, which is not susceptible to decrease in the antistatic function and the degree of polarization even in cases where the polarizing film with an adhesive layer is exposed to a humidified environment, and which has excellent transparency. A polarizing film with an adhesive layer according to the present invention comprises a polarizing film and an adhesive layer that is provided on the polarizing film, and is characterized in that: the polarizing film has a transparent protective film on only one side of a polarizer, while having the adhesive layer arranged on the other side of the polarizer, on which the transparent protective film is not provided; the adhesive layer is formed from an adhesive composition that contains a (meth)acrylic polymer and an alkali metal salt; and the (meth)acrylic polymer contains, as a monomer unit, a monomer (1) which comprises a nitrogen atom and a carbon-carbon double bond.

Description

Polarizing film with adhesive layer and image display device

The present invention relates to a polarizing film having a polarizing film and an adhesive layer provided on an adhesive layer of the polarizing film. Further, the present invention relates to a liquid crystal display device using the above-described polarizing film with an adhesive layer, an organic EL display device, and an image display device such as a PDP.

BACKGROUND OF THE INVENTION Liquid crystal display devices and the like are indispensable for arranging polarizing elements on both sides of a liquid crystal cell from the viewpoint of image formation, and generally a polarizing film is attached. When the polarizing film is attached to a liquid crystal cell, an adhesive is usually used. Further, in order to reduce the loss of light, the polarizing film and the liquid crystal cell are usually adhered to each other using an adhesive. In this case, a polarizing film having an adhesive layer which is previously provided on the one side of the polarizing film in the form of an adhesive layer is generally used because it does not require a drying step when the polarizing film is fixed. advantage. Further, a release film is usually attached to the adhesive layer of the polarizing film with the adhesive layer.

When the liquid crystal display device is manufactured, when the polarizing film with the adhesive layer is attached to the liquid crystal cell, the release film is peeled off from the adhesive layer of the polarizing film with the adhesive layer, but the release film is removed. Stripping produces static electricity. The static electricity thus generated affects the alignment of the liquid crystal layer inside the liquid crystal display device, causing defects. Further, when the liquid crystal display device is used, there is a case where display unevenness due to static electricity is caused. The generation of static electricity can be suppressed by, for example, forming an antistatic layer on the outer surface of the polarizing film, but the effect is small, and there is a problem that static electricity cannot be prevented from being fundamentally prevented. Therefore, in order to suppress the generation from the fundamental position where static electricity is generated, it is sought to impart an antistatic function to the adhesive layer. A means for imparting an antistatic function to the adhesive layer has been proposed, for example, by incorporating an ionic compound into an adhesive for forming an adhesive layer (Patent Documents 1 to 3). In detail, Patent Document 1 proposes an adhesive composition for an optical film in which an alkali metal salt and/or an organic cation-anion salt is blended. Patent Document 2 proposes an adhesive composition containing a cerium-anion and an alkali metal salt as an adhesive layer raw material of a polarizing film with an adhesive layer. Patent Document 3 proposes an adhesive composition containing an alkali metal salt as a raw material of an adhesive layer of an adhesive polarizing plate.

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SUMMARY OF THE INVENTION Problems to be Solved by the Invention In the case of a polarizing film with an adhesive layer, a transparent protective film is provided on one side of the polarizing member alone, and an adhesive layer is provided on the other side without providing a transparent protective film. A polarizing film with an adhesive layer. Since the polarizing film with the adhesive layer has a transparent protective film on only one side, the cost of the layer of the transparent protective film can be reduced as compared with the case where the transparent protective film is provided on both sides. However, the alkali metal salt described in Patent Documents 1 to 3, particularly lithium bis(trifluoromethanesulfonyl) quinone imine (LiTFSI), is blended in the adhesive layer of the polarizing film with the adhesive layer. When the lithium-organic anion salt is used as the ionic compound, if the polarizing film of the adhesive layer is exposed to a humidified environment, a new problem of a decrease in the antistatic function of the adhesive layer occurs. On the other hand, when the organic cation-anion salt is blended in the adhesive layer of the polarizing film with the adhesive layer, if the polarizing film of the adhesive layer is exposed to a humidifying environment, the polarized light is polarized. The article deteriorates, causing problems such as fading, reduction in polarization, and the like.

Further, if the antistatic function of the adhesive layer of the polarizing film with the adhesive layer is increased to increase the content of the ionic compound in the adhesive layer, the adhesive layer may become cloudy and the transparency may be lowered to cause adhesion. The problem of reduced optical properties of the polarizing film of the adhesive layer.

SUMMARY OF THE INVENTION An object of the present invention is to provide a polarizing film with an adhesive layer which is not easily degraded and has excellent transparency even when exposed to a humidifying environment.

Further, it is an object of the invention to provide an image display device using the polarizing film with the above-mentioned adhesive layer.

MEANS TO SOLVE THE PROBLEM The present inventors have intensively studied in order to solve the above-mentioned problems, and as a result, the following polarizing film with an adhesive layer was discovered, and the present invention was completed.

That is, the present invention relates to a polarizing film with an adhesive layer, comprising a polarizing film and an adhesive layer disposed on the polarizing film, wherein the polarizing film of the adhesive layer is characterized in that: the polarizing film is only a single of the polarizing member. The side has a transparent protective film, and the adhesive layer is disposed on a side of the polarizing member that does not have the transparent protective film; and the adhesive layer is composed of a (meth)acrylic polymer and an adhesive composition containing an alkali metal salt. The formed (meth)acrylic polymer contains a monomer (1) having a nitrogen atom and a carbon-carbon double bond as a monomer unit.

When the adhesive layer of the polarizing film with the adhesive layer is mixed with an alkali metal salt such as a lithium-organic anion salt, if the polarizing film of the adhesive layer is exposed to a humidifying environment, the antistatic function of the adhesive layer The inventors think that the reason is that the alkali metal salt exhibits a strong interaction with the iodine in the polarizing member, so if the adhesive layer is exposed to a humidifying environment, the alkali metal salt in the adhesive layer will go to The polarizer side moves and partially exists, so that the surface resistance value of the adhesive layer becomes large. Further, it has been found that a (meth)acrylic polymer which introduces a monomer (1) having a nitrogen atom and a carbon-carbon double bond by copolymerization is used as a base polymer of an adhesive layer, whereby even the adhesive layer is exposed. In a humidified environment, antistatic performance is also not easy to drop. The reason is presumed as follows. By the interaction of a (meth)acrylic polymer having a monomer (1) having a nitrogen atom and a carbon-carbon double bond with an alkali metal salt by copolymerization, the alkali metal salt in the adhesive layer is not easily polarized The movement of the member side suppresses the local presence on the side of the polarizer, so that the increase in the surface resistance value of the adhesive layer is suppressed.

Further, since the (meth)acrylic polymer having a monomer (1) having a nitrogen atom and a carbon-carbon double bond introduced by a copolymerization has a polar group, compatibility with an alkali metal salt can be improved, and even if a base is added The content of the metal salt, the adhesive layer is also less turbid, and the transparency of the adhesive layer is not easily lowered. Therefore, it is possible to suppress a decrease in optical characteristics of the polarizing film with the adhesive layer.

Further, when the organic cation (anion)-anion salt is blended in the adhesive layer, the interaction between the organic cation ions and the iodine anion in the polarizer is low, so the interaction is small. Therefore, when the polarizing film with the adhesive layer is exposed to a humidifying environment, iodine in the polarizing member tends to flow out of the outside (in the adhesive). The result is that the polarizer is deteriorated and the degree of polarization is lowered. The present inventors have found that by incorporating an alkali metal salt into the polarizing film of the adhesive layer, even if the polarizing film of the adhesive layer is exposed to a humidifying environment, the polarizing member is not easily deteriorated, and the degree of polarization is not easily lowered. . The reason is presumed as follows. Since the alkali metal cation has a high bonding energy with the iodine anion in the polarizing member, the interaction thereof is also large, and at the interface between the adhesive layer and the polarizing member, the alkali metal cation can stabilize the iodine complex in the polarizing member. Therefore, even if the polarizing film with the adhesive layer is exposed to a humidifying environment, iodine in the polarizing member does not easily flow out of the outside (in the adhesive). It is considered that the result is that the polarizer is less likely to deteriorate and the degree of polarization is not easily lowered.

The alkali metal in the alkali metal salt is preferably bonded to the iodine anion (I ^- ) at 50 kcal/mol or more, and is preferably lithium.

The aforementioned monomer (1) preferably has a guanamine group. Further, the monomer (1) preferably has a hetero ring containing a nitrogen atom.

The (meth)acrylic polymer preferably contains 0.1 to 10% by weight of the monomer (1) as a monomer unit.

The above-mentioned adhesive composition preferably contains 0.01 to 5 parts by weight of an alkali metal salt based on 100 parts by weight of the (meth)acryl-based polymer.

The rate of change of the surface resistance value (B) and the surface resistance value (A) of the pressure-sensitive adhesive layer (B × 100 / A) is preferably 700% or less, and the surface resistance value (B) is stored at 60 ° C / 90 The resistance value after 500 hours in a humidified environment of %RH, and the surface resistance value (A) is a resistance value before storage in the humidification environment.

Further, the surface resistivity (A) of the pressure-sensitive adhesive layer before storage in the humidifying environment is preferably 1.0 × 10 ¹¹ Ω / □ or less.

As the polarizing film with the above adhesive layer, those having a thickness of 12 μm or less can be used as the polarizing member.

Further, the amount of change (AB) between the degree of polarization (B) and the degree of polarization (A) of the polarizing film with the adhesive layer is preferably within 0.05, and the degree of polarization (B) is stored at 60 ° C / 90% RH. The degree of polarization after 500 hours in a humidified environment, and the degree of polarization (A) is the degree of polarization before storage in the humidified environment.

Further, the present invention relates to an image display device characterized in that a polarizing film having at least one layer of the above-mentioned adhesive layer is used.

Advantageous Effects of Invention The adhesive layer of the polarizing film with an adhesive layer of the present invention contains a (meth)acrylic polymer and an alkali metal salt which are introduced into a monomer (1) having a nitrogen atom and a carbon-carbon double bond by copolymerization. By using these in combination, it is possible to obtain a polarizing film with an adhesive layer which is not easily deteriorated by exposure to an antistatic function and a degree of polarization in a humidified environment and which is excellent in transparency. The monomer (1) is a monomer having a guanamine group and having a hetero ring containing a nitrogen atom, and when the alkali metal in the alkali metal salt is lithium, the effect of the present invention is the highest.

The adhesive composition for forming the pressure-sensitive adhesive layer of the polarizing film with an adhesive layer of the present invention contains a (meth)acrylic polymer as a base polymer. The (meth)acrylic polymer usually contains an alkyl (meth)acrylate as a main component. Further, (meth) acrylate means acrylate and/or methacrylate, and (meth) of the present invention has the same meaning.

The (meth)acrylic acid alkyl ester constituting the main skeleton of the (meth)acrylic polymer may, for example, be a linear or branched alkyl group having 1 to 18 carbon atoms. For example, the aforementioned alkyl group may, for example, be a methyl group, an ethyl group, a propyl group, a propyl group, a butyl group, a butyl group, a pentyl group, a hexyl group, a cyclohexyl group, a heptyl group, a 2-ethylhexyl group, an anthranyl group or a fluorenyl group. , sulfhydryl, sulfhydryl, dodecyl, carbaryl, lauryl, thirteen, fifteen, sixteen, seventeen, eighteen, and the like. These may be used alone or in combination. The average carbon number of the alkyl groups is preferably from 3 to 9.

The weight ratio of the alkyl (meth)acrylate is preferably 70% by weight or more based on the weight ratio of the total constituent monomer (100% by weight) constituting the (meth)acrylic polymer. The weight ratio of alkyl (meth)acrylate can be considered as the remainder of the nitrogen-containing monomer and other comonomers. In order to ensure the adhesion, the weight ratio of the alkyl (meth)acrylate is preferably set to the above range.

In order to exhibit the effects of the present invention, a monomer (1) having a nitrogen atom and a carbon-carbon double bond is introduced into the (meth)acrylic polymer by copolymerization.

The monomer (1) has a nitrogen atom and contains a polymerizable unsaturated double bond such as a (meth)acryl fluorenyl group or a vinyl group. The monomer (1) may, for example, be a maleimide monomer such as maleimide, N-cyclohexylmaleimide or N-phenylmaleimide; N-(methyl) Propylene methoxymethylene succinimide, N-(methyl) propylene fluorenyl-6-oxyhexamethylene succinimide, N-(methyl) propylene fluorenyl-8-oxy VIII Amber quinone imine monomer such as methylene amber succinimide; N-methyl konkonium imine, N-ethyl thiene imine, N-butyl Ikonide, N-octyl Ikonium imine, N-2-ethylhexylkamponium imine, N-cyclohexylidene imine, N-lauryl ikonium imine, etc. Ikonide imine monomer; acrylonitrile , cyano (meth) acrylate monomer such as methacrylonitrile; amine ethyl (meth) acrylate, amine propyl (meth) acrylate, N, N-dimethylamine (meth) acrylate (meth)acrylic acid aminoalkyl monomer such as ester, tributyl butyl (meth) acrylate, 3-(3-pyridyl) propyl (meth) acrylate; (meth) propylene Indoleamine, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropylacrylamide, N-methyl (methyl) Acrylamide, N-butyl (Meth) acrylamide, N-hexyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylol-N-propane (meth) acrylamide, amine (Meth) acrylamide, such as methyl (meth) acrylamide, amine ethyl (meth) acrylamide, hydrazine methyl (meth) acrylamide, decyl ethyl (meth) acrylamide Monomer; N-(methyl)propenyl carbaryl, N-(methyl)propenylpiperidine, N-(methyl)propenylpyridinium a heterocyclic monomer containing N-(meth)acrylinyl group; N-(methyl)propenylpyrrolidone, N-(methyl)propenylpiperidone, N-(methyl)propene N-(methyl)acrylonitrile-containing indoleamine monomer such as thiol-ε-caprolactam; N-vinylpyrrolidone, N-vinylpiperidone, N-vinyl-ε - an internal amide group containing N-vinyl group such as caprolactam; vinylpyrrolidone , vinyl piperidine, vinyl pyridine, vinyl pyrimidine, vinyl pipe Vinylpyr , vinyl pyrrole, vinyl imidazole, vinyl a heterocyclic-containing vinyl monomer such as azole or vinyl phenylephrine. These may be used alone or in combination. Among them, a (meth) acrylamide monomer, a N-(meth)acryl fluorenyl group-containing heterocyclic monomer, an N-(meth) acrylonitrile group-containing decylamine monomer, and a A mercaptoamine-containing monomer such as an N-vinyl indoleamine-based monomer, preferably an N-(meth)acrylinyl-containing indoleamine-based monomer and an N-vinyl-containing indoleamine The internal guanamine monomer is preferably a monomer or the like, and the N-vinyl containing indoleamine monomer is particularly preferred.

From the viewpoint of suppressing an increase in the surface resistance value of the adhesive layer when the adhesive layer is exposed to a humidified environment, a viewpoint of suppressing a decrease in the degree of polarization when the polarizing film with the adhesive layer is exposed to a humidifying environment, and even if adhesion is improved The weight ratio of the monomer (1) is preferably 0.1 to 10% by weight, more preferably 1 to 5% by weight, more preferably 1 to 5% by weight, from the viewpoint that the content of the alkali metal salt in the agent layer can maintain the transparency of the adhesive layer. ~3% by weight is especially preferred. If the weight ratio of the nitrogen-containing monomer is less than 0.1% by weight, the surface resistivity of the adhesive layer is likely to rise when the adhesive layer is exposed to a humidifying environment, or when the content of the alkali metal salt in the adhesive layer is increased. The transparency of the adhesive layer tends to decrease. On the other hand, when the weight ratio of the nitrogen-containing monomer is more than 10% by weight, when the polarizing film of the adhesive layer is exposed to a humidified environment, the degree of polarization tends to decrease and the workability tends to decrease.

In order to improve the adhesiveness and the heat resistance, one or more polymerizable functional groups having an unsaturated double bond such as a (meth)acryl fluorenyl group or a vinyl group may be introduced into the (meth)acrylic polymer by copolymerization. Comonomer. Specific examples of the comonomer include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and (meth)acrylic acid 6- Hydroxyhexyl ester, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate or (4-hydroxymethylcyclohexyl)-methacrylic acid a hydroxyl group-containing monomer such as an ester; a carboxyl group such as (meth)acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid or the like Monomer; acid anhydride group-containing monomer such as maleic anhydride or itaconic anhydride; (meth)acrylic acid alkoxyalkyl group such as methoxyethyl (meth)acrylate or ethoxyethyl (meth)acrylate a monomer; a sulfonic acid group-containing monomer such as styrenesulfonic acid or allylsulfonic acid, sulfopropyl (meth)acrylate, (meth)acryloxynaphthalenesulfonic acid; 2-hydroxyethylpropene oxime A phosphate group-containing monomer or the like.

Further, a vinyl monomer such as vinyl acetate, vinyl propionate, styrene or α-methylstyrene; or an epoxy group-containing acrylic monomer such as glycidyl (meth)acrylate; Glycol acrylates such as polyethylene glycol methacrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate An acrylate monomer such as tetrahydrofurfuryl (meth) acrylate, fluorine (meth) acrylate or polydecane oxy (meth) acrylate is used as a modified monomer. Further, isoprene, butadiene, isobutylene, vinyl ether and the like can be mentioned.

Further, the monomer which can be copolymerized other than the above may be a decane-based monomer containing a ruthenium atom. The decane-based monomer may, for example, be 3-propenyloxypropyltriethoxydecane, vinyltrimethoxydecane, vinyltriethoxydecane, 4-vinylbutyltrimethoxydecane or 4-ethylene. Butyl triethoxy decane, 8-vinyloctyltrimethoxydecane, 8-vinyloctyltriethoxydecane, 10-methylpropenyloxydecyltrimethoxydecane, 10-propene醯 methoxy decyl trimethoxy decane, 10-methyl propylene decyl decyl triethoxy decane, 10-propylene decyl decyl triethoxy decane, and the like.

Further, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, bisphenol A diepoxypropyl group can also be used. Ether di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol IV Two or more esterified products of (meth)acrylic acid and polyhydric alcohol such as (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate a polyfunctional monomer having an unsaturated double bond such as a (meth) acrylonitrile group or a vinyl group, or two or more (meth) acrylonitrile groups or ethylene added to a skeleton such as a polyester, an epoxy or a urethane. As the comonomer, a polyester (meth) acrylate, an epoxy (meth) acrylate, a urethane (meth) acrylate or the like having an unsaturated double bond as a functional group similar to the monomer component is used.

Among these comonomers, a hydroxyl group-containing monomer or a carboxyl group-containing monomer is preferably used from the viewpoint of adhesion and durability. Further, a hydroxyl group-containing monomer and a carboxyl group-containing monomer may be used in combination. These comonomers become a reaction point with the crosslinking agent when the adhesive composition contains a crosslinking agent. The hydroxyl group-containing monomer, the carboxyl group-containing monomer, and the like have good reactivity with the crosslinking agent between the molecules, and therefore are suitable for improving the cohesiveness and heat resistance of the obtained pressure-sensitive adhesive layer. It is preferable to use a hydroxyl group-containing monomer from the viewpoint of reworkability, and it is preferable to use a carboxyl group-containing monomer from the viewpoint of achieving both durability and reworkability.

When the hydroxyl group-containing monomer is contained as a comonomer, the ratio is preferably 0.01 to 15% by weight, preferably 0.03 to 10% by weight, more preferably 0.05 to 7% by weight. Further, when a carboxyl group-containing monomer is contained as a comonomer, the ratio is preferably 0.05 to 10% by weight, preferably 0.1 to 8% by weight, more preferably 0.2 to 6% by weight.

The (meth)acrylic polymer of the present invention is usually one having a weight average molecular weight of from 500,000 to 3,000,000. In consideration of durability, particularly heat resistance, it is preferred to use a weight average molecular weight of 700,000 to 2.7 million. More than 800,000 to 2.5 million is appropriate. When the weight average molecular weight is less than 500,000, it is not preferable from the viewpoint of heat resistance. Further, if the weight average molecular weight becomes more than 3,000,000, a large amount of a diluting solvent is required to adjust the viscosity required for coating to increase the cost, which is not preferable. Further, the weight average molecular weight means a value measured by GPC (Gel Permeation Chromatography) and calculated in terms of polystyrene.

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

Further, in the solution polymerization, for example, ethyl acetate, toluene or the like can be used as the polymerization solvent. In the specific solution polymerization example, the reaction may be carried out by adding a polymerization initiator under an inert gas stream such as nitrogen, and usually carried out under the reaction conditions of about 50 to 70 ° C for about 5 to 30 hours.

The polymerization initiator, the chain transfer agent, the emulsifier, and the like used in the radical polymerization are not particularly limited, and can be appropriately selected and used. Further, the weight average molecular weight of the (meth)acrylic polymer can be controlled by the amount of the polymerization initiator, the chain transfer agent used, and the reaction conditions, and the appropriate amount of use should be adjusted depending on the type.

Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-amidinopropane) dihydrochloride, and 2,2'-azobis[2- (5-methyl-2-imidazolin-2-yl)propane] dihydrochloride, 2, 2'-azobis(2-methylpropionamidine) disulfate, 2, 2'-azo double (N, N'-Dimethylene isobutyl hydrazine), 2, 2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine hydrate (manufactured by Wako Pure Chemical Industries, Ltd.) , VA-057) and other azo initiators; potassium persulfate, ammonium persulfate, etc., persulphate, di(2-ethylhexyl)peroxydicarbonate, bis(4-tert-butylcyclohexyl) Peroxydicarbonate, di-secondary butyl peroxydicarbonate, tertiary butyl peroxy neodecanoate, tertiary hexyl peroxy-3-acetate, tertiary butyl peroxytrimethylacetate , laurel-based peroxide, di-n-octyl decyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, bis(4-methylphenyl) Mercapto) peroxide, benzhydryl peroxide, tertiary butyl peroxybutyrate, 1,1-di(tri-hexylperoxy)cyclohexane, tertiary butyl hydroperoxide, Peroxide such as hydrogen peroxide Initiator; redox and persulfate, a peroxide and sodium ascorbate combination of sodium bisulfite in combination with a reducing agent a combination of a peroxide initiator and the like, but not limited thereto.

The polymerization initiator may be used singly or in combination of two or more. The total content is preferably from 0.005 to 1 part by weight, more preferably from 0.02 to 0.5 part by weight, per 100 parts by weight of the monomer.

Further, when the (meth)acrylic polymer having the above weight average molecular weight is produced by using, for example, 2'2-azobisisobutyronitrile as a polymerization initiator, the polymerization initiator is used in an amount of 100 relative to the total amount of the monomer components. The weight portion is preferably set to about 0.06 to 0.2 parts by weight, more preferably about 0.08 to 0.175 parts by weight.

The chain transfer agent may, for example, be lauryl mercaptan, epoxypropyl mercaptan, indole acetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, 2,3-didecyl- 1-propanol and the like. The chain transfer agent may be used singly or in combination of two or more kinds thereof, but the total content is about 0.1 part by weight or less based on 100 parts by weight of the total amount of the monomer components.

Further, examples of the emulsifier used in the emulsion polymerization include sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, polyoxyethylene ethyl ether ether sulfate, and polyoxyalkylene methyl group. Anionic emulsifier such as sodium phenyl ether sulfate, polyoxyethylene ethyl ether, polyoxyethylidene ether, polyoxyethyl ester, polyoxyethylene ethyl-polyoxyethylene A nonionic emulsifier such as a propyl block polymer. These emulsifiers may be used alone or in combination of two or more.

Further, in the case of the reactive emulsifier, an emulsifier which introduces a radical polymerizable functional group such as an acryl group or an allyl ether group, specifically, Aqualon HS-10, HS-20, KH-10, BC-05, BC-10, BC-20 (all of which are manufactured by First Industrial Pharmaceutical Co., Ltd.), ADEKA REASOAP SE10N (made by Asahi Chemical Co., Ltd.), etc. Since the reactive emulsifier is incorporated into the polymer chain after polymerization, it is preferred that the water resistance is good. The amount of the emulsifier used is 0.3 to 5 parts by weight based on 100 parts by weight of the total of the monomer components, and is preferably 0.5 to 1 part by weight in terms of polymerization stability and mechanical stability.

The adhesive composition of the present invention contains an alkali metal salt in addition to the aforementioned (meth)acrylic polymer.

As the alkali metal salt, an organic salt of an alkali metal and an inorganic salt can be used.

The alkali metal ion constituting the cationic portion of the alkali metal salt may, for example, be an ion such as lithium, sodium or potassium. The alkali metal ion can increase the bond between the alkali metal ion and the iodine anion (I ^- ) at 50 kcal/mol from the viewpoint of increasing the interaction with the iodine anion in the polarizer to stabilize the iodine complex in the polarizer. The above is preferred, more preferably 70 kcal/mol or more, particularly preferably 85 kcal/mol or more, and particularly preferably 105 kcal/mol or more. From the above viewpoints, among the alkali metal ions, a lithium ion having a bonding energy with an iodine anion (I ^- ) of 140.8 kcal/mol is preferred. In addition, when the monomer (1) introduced by copolymerization in the (meth)acrylic polymer is alkaline, when the (meth)acrylic polymer is in contact with the polarizer, the polarizer is deteriorated. It is prone to fading. However, if the alkali metal ion constituting the cation portion of the alkali metal salt is lithium ion, since the iodine complex in the polarizer can be stabilized, fading of the polarizer can be effectively suppressed.

The anion portion of the alkali metal salt may be composed of an organic substance or an inorganic substance. In order to make the alkali metal salt in the adhesive layer difficult to move toward the polarizer side, it is preferred that the anion portion has a high bulk density. As the anion portion constituting the organic salt, for example, 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 may be used. 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 formula (1) To (4), etc.: (1): (C _n F _{2n +1} SO ₂ ) ₂ N ^- (only, n is an integer from 1 to 10), (2): CF ₂ (C _m F _2m SO _{2 2} N ^- (only, m is an integer from 1 to 10), (3): ^- O ₃ S(CF ₂ ) _l SO ₃ ^- (only, l is an integer from 1 to 10), (4): (C _p F _{2p +1} SO ₂ )N ^- (C _q F _{2q +1} SO ₂ ), (p, q is an integer from 1 to 10). In particular, the anion portion of the fluorine-containing atom is suitably used because it can obtain an ionic compound having good ion dissociation properties. The anion portion constituting the inorganic salt may be 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. The anion moiety is preferably a compound having a high bulk density as described above, and is preferably represented by the above formula (1) such as (CF ₃ SO ₂ ) ₂ N ^- , (C ₂ F ₅ SO ₂ ) ₂ N ^- The fluoroalkylsulfonyl) quinone imine, and particularly (CF ₃ SO ₂ ) ₂ N ^- (trifluoromethanesulfonyl) quinone imine is preferred.

The organic salt of an alkali metal may specifically be sodium acetate, sodium alginate, sodium lignosulfonate, sodium p-toluenesulfonate, LiCF ₃ SO ₃ , Li(CF ₃ SO ₂ ) ₂ N, Li(CF ₃ SO ₂ ). ₂ N, Li(C ₂ F ₅ SO ₂ ) ₂ N, Li(C ₄ F ₉ SO ₂ ) ₂ N, Li(CF ₃ SO ₂ ) ₃ C, KO ₃ S(CF ₂ ) ₃ SO ₃ K, LiO ₃ S(CF ₂ ) ₃ SO ₃ K, etc., and among these are 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, etc., 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 and other fluorine-containing lithium sulfoxide salts are more preferable, and (perfluoroalkylsulfonyl) quinone imide lithium salt is particularly preferable.

Further, examples of the inorganic salt of an alkali metal include lithium perchlorate and lithium iodide.

In order to obtain the effects of the present invention, the content of the alkali metal salt in the adhesive composition of the present invention is preferably 0.01 to 5 parts by weight, more preferably 0.1 to 4.5 parts by weight, per 100 parts by weight of the (meth)acrylic polymer. Good, 0.5~4 parts by weight is especially good. When the content of the alkali metal salt is less than 0.01 parts by weight, it is difficult to impart an antistatic function to the adhesive layer. On the other hand, when the content of the alkali metal salt is more than 5 parts by weight, even if the (meth)acrylic polymer is used, the adhesive layer may be cloudy and the transparency of the adhesive layer tends to be lowered.

The adhesive composition of the present invention may contain a known organic cation-anion salt (as described in Japanese Patent Laid-Open No. 2014-048497), within a range that does not impair the effects of the present invention.

Further, the adhesive composition of the present invention may contain a crosslinking agent. As the crosslinking agent, an organic crosslinking agent or a polyfunctional metal chelate compound can be used. Examples of the organic crosslinking agent include an isocyanate crosslinking agent, a peroxide crosslinking agent, an epoxy crosslinking agent, and an imide crosslinking agent. Polyfunctional metal chelates are those in which a polyvalent metal is covalently bonded or coordinately bonded to an organic compound. Examples of the polyvalent metal atom include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, and Ti. The atom which may be covalently bonded or coordinately bonded to the organic compound may, for example, be an oxygen atom, and the organic compound may, for example, be an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound or a ketone compound.

The crosslinking agent is preferably an isocyanate crosslinking agent and/or a peroxide crosslinking agent. Examples of the isocyanate crosslinking agent compound include isocyanate such as toluene diisocyanate, chlorophenyl diisocyanate, tetramethylene diisocyanate, decyl diisocyanate, diphenylmethane diisocyanate, and hydrogenated diphenylmethane diisocyanate. a monomer, and an isocyanate compound or a trimeric isocyanate compound or a biuret type compound obtained by adding such an isocyanate monomer to trimethylolpropane or the like, and a polyether polyol or a polyester polyol or an acrylic polyol. A urethane prepolymer type isocyanate obtained by addition reaction of an alcohol, a polybutadiene polyol, a polyisoprene polyol, or the like. More preferably, the polyisocyanate compound is one selected from the group consisting of hexamethylene isocyanate, hydrogenated deuterated diisocyanate, and isophorone diisocyanate, or a polyisocyanate compound derived therefrom. Here, the polyisocyanate compound selected from the group consisting of hexamethylene isocyanate, hydrogenated deuterated diisocyanate, and isophorone diisocyanate or a polyisocyanate compound thereof includes: hexamethylene isocyanate, Hydrogenated decyl diisocyanate, isophorone diisocyanate, polyol modified hexamethylene isocyanate, polyol modified hydrogenated decyl diisocyanate, terpolymer hydrogenated deuterated diisocyanate and polyol modified Carbaryl diisocyanate and the like. The reaction between the polyisocyanate compound and the hydroxyl group exemplified is preferably carried out by rapidly causing an acid or a base contained in the polymer to be a catalyst, and therefore it is particularly preferable for the crosslinking rate.

The peroxide-based crosslinking agent can be suitably used as long as it generates a radical active species by heating or light irradiation, and the base polymer of the adhesive composition is crosslinked, but it is preferable to use it in consideration of workability and stability. 1 minute half-life peroxide at 80 ° C ~ 160 ° C, and preferably used at 90 ° C ~ 140 ° C peroxide.

Useful peroxides are bis(2-ethylhexyl)peroxydicarbonate (1 minute half-life temperature: 90.6 ° C), bis(4-tributylcyclohexyl)peroxydicarbonate (1 minute). Half-life temperature: 92.1 ° C), di- or di-butyl peroxydicarbonate (1 minute half-life temperature: 92.4 ° C), peroxy neodecanoic acid tert-butyl ester (1 minute half-life temperature: 103.5 ° C), trimethyl peroxide Tertiary hexyl acetate (1 minute half-life temperature: 109.1 ° C), trimethyl butyl peroxyacetate (1 minute half-life temperature: 110.3 ° C), dilauroyl peroxide (1 minute half-life temperature: 116.4) °C), di-n-octyl peroxide (1 minute half-life temperature: 117.4 ° C), 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (1 minute half-life temperature: 124.3 °C), bis(4-methylbenzhydryl) peroxide (1 minute half-life temperature: 128.2 ° C), benzoyl peroxide (1 minute half-life temperature: 130.0 ° C), perisobutyric acid III Butyl ester (1 minute half-life temperature: 136.1 ° C), 1,1-di(tri-hexylperoxy)cyclohexane (1 minute half-life temperature: 149.2 ° C), and the like. Among them, from the viewpoint of excellent crosslinking reaction efficiency, especially bis(4-tert-butylcyclohexyl)peroxydicarbonate (1 minute half-life temperature: 92.1 ° C), dilauroyl peroxide (1) Minute half-life temperature: 116.4 ° C), benzoyl hydrazine peroxide (1 minute half-life temperature: 130.0 ° C), etc. are suitable for use.

Further, the half-life of the peroxide is an index showing the decomposition rate of the peroxide, and means the time when the residual amount of the peroxide becomes half. The decomposition temperature required for the half-life at any time or the half-life time at any temperature is described in the manufacturer's catalog, etc., for example, in the "Organic Peroxide Catalogue" of Nippon Oil & Fat Co., Ltd. 9th edition (May 2003) and so on.

The amount of the crosslinking agent used is preferably 0.01 to 20 parts by weight, more preferably 0.03 to 10 parts by weight, per 100 parts by weight of the (meth)acrylic polymer. When the amount of the crosslinking agent is less than 0.01 part by weight, the cohesive force of the adhesive tends to be insufficient, and there is a fear that bubbles may be generated during heating. On the other hand, if it is more than 20 parts by weight, the moisture resistance is insufficient. It is easy to peel off at the time of reliability test or the like.

The isocyanate-based crosslinking agent may be used singly or in combination of two or more kinds thereof, and the total content is preferably 0.01 to 2 parts by weight based on 100 parts by weight of the (meth)acryl-based polymer. It is preferably a mixture of 0.02 to 2 parts by weight, more preferably 0.05 to 1.5 parts by weight. The crosslinking agent can be appropriately contained in consideration of the cohesive force and the peeling during the durability test.

The peroxide may be used singly or in combination of two or more kinds, but the total content is 0.01 to 2 parts by weight based on 100 parts by weight of the (meth)acrylic polymer. It is preferably contained in an amount of 0.04 to 1.5 parts by weight, more preferably 0.05 to 1 part by weight. It can be appropriately selected within this range to adjust workability, reworkability, crosslinking stability, peelability, and the like.

Further, the method for measuring the amount of decomposition of the peroxide remaining after the reaction treatment can be measured, for example, by HPLC (High Performance Liquid Chromatography).

More specifically, for example, about 0.2 g of the post-reaction adhesive composition is taken out each time, immersed in 10 ml of ethyl acetate, and subjected to vibration extraction at 25 ° C, 120 rpm for 3 hours, and then statically shaken at room temperature. Set 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 filtration using a membrane filter (0.45 μm) was injected into HPLC for analysis, and the amount of peroxide after the reaction treatment was obtained.

Further, the adhesive composition of the present invention may contain a decane coupling agent. Durability can be improved by using a decane coupling agent. Specific examples of the decane coupling agent include 3-glycidoxypropyltrimethoxydecane, 3-glycidoxypropyltriethoxydecane, and 3-glycidoxypropylmethyldi Epoxy-containing decane coupling agent such as ethoxy decane or 2-(3,4-epoxycyclohexyl)ethyltrimethoxy decane; 3-aminopropyltrimethoxydecane, N-2-(amine B 3-aminopropylmethyldimethoxydecane, 3-triethoxyindolyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-γ-aminopropyl An amine group-containing decane coupling agent such as trimethoxy decane; (meth) acryl oxime group such as 3-propenyl methoxypropyltrimethoxy decane or 3-methyl propylene oxypropyl triethoxy decane a decane coupling agent; an isocyanate group-containing decane coupling agent such as 3-isocyanate propyl triethoxy decane.

The decane coupling agent may be used singly or in combination of two or more kinds. The total content of the decane coupling agent is preferably 0.001 to 5 parts by weight based on 100 parts by weight of the (meth)acrylic polymer. It is preferably 0.01 to 1 part by weight, more preferably 0.02 to 1 part by weight, still more preferably 0.05 to 0.6 part by weight. In order to improve durability, the content of adhesion to an optical member such as a liquid crystal cell is moderately maintained.

Further, the adhesive composition of the present invention may be blended with a polyether modified polysiloxane. As the polyether-modified polysiloxane, for example, those disclosed in Japanese Laid-Open Patent Publication No. 2010-275522 can be used.

The polyether modified polyoxosiloxane has a polyether skeleton and has a reactive thiol group represented by the following formula (1) at at least one terminal: Formula (1): -SiR _a M _3-a (wherein R may also have a monovalent organic group having 1 to 20 carbon atoms of the 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 R, a plurality of R may be the same They can also be different from each other; when there are multiple Ms, multiple Ms can be mutually different or different).

The polyether-modified polyfluorene oxide compound may be a compound represented by the following formula (2): General formula (2): R _a M _3-a Si-XY-(AO) _n -Z (wherein R system Further, it may have a monovalent organic group having 1 to 20 carbon atoms of the substituent, M-based hydroxyl group or hydrolyzable group, and a is an integer of 0 to 2; however, when there are a plurality of R, a plurality of R may be mutually the same When there are multiple Ms, multiple Ms may be mutually different or different; AO represents a linear or branched carbon number of 1 to 10, and n is 1 to 1700, indicating oxygen The average addition molar number of the base; X represents a linear or branched alkyl group having 1 to 20 carbon atoms; 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, a group represented by the following formula (2A) or formula (2B): Formula (2A): -Y ¹ -X-SiR _a M _3-a (wherein , R, M, X are the same as previously described; Y ¹ represents a single bond, a -CO- bond, a -CONH- bond or a -COO- bond), and a formula (2B): -Q{-(OA) _n -YX-SiR _a M _3-a } _m (wherein R, M, X, and Y are the same as above; OA is the same as AO described above, n is the same as the above; Q is a hydrocarbon group having a carbon number of 1 to 10 or more having a valence of 2 or more, m and The hydrocarbon group has the same valence)).

Specific examples of the polyether-modified polyoxo compound include, for example, MS POLYMER S203, S303, and S810 manufactured by KANEKA Co., Ltd.; SILYL EST250 and EST280; SAT10, SAT200, SAT220, SAT350, and SAT400; and EXCESTAR S2410 and S2420 manufactured by Asahi Glass Co., Ltd. or S3430 and so on.

Further, the adhesive composition of the present invention may contain other known additives. For example, a polyether compound such as a polyalkylene glycol such as polypropylene glycol, a powder such as a coloring agent or a pigment, a dye, a surfactant, or the like may be appropriately added depending on the intended use. Plasticizer, tackifier, surface lubricant, leveling agent, softener, antioxidant, anti-aging agent, light stabilizer, ultraviolet absorber, polymerization inhibitor, inorganic or organic filler, metal powder, particulate , foil, etc. Further, a redox system to which a reducing agent is added may be employed within a controllable range.

Although the adhesive layer is formed by using the above-mentioned adhesive composition, when the adhesive layer is formed, it is preferable to adjust the amount of the entire crosslinking agent to be added, and to fully consider the influence of the crosslinking treatment temperature and the crosslinking treatment time.

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 less.

Further, the crosslinking treatment may be carried out at a temperature at the drying step of the adhesive layer, or may be carried out by additionally providing a crosslinking treatment step after the drying step.

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

The polarizing film of the adhesive layer of the present invention is such that a transparent protective film is provided only on one side of the polarizing member, and a transparent protective film is not provided on the other side, and an adhesive layer is formed on the polarizing member by using the above-mentioned adhesive composition.

The method of forming the adhesive layer can be carried out, for example, by applying the above-mentioned adhesive composition to a release-treated separator, drying and removing a polymerization solvent or the like to form an adhesive layer, and then transferring the polarized light to a polarizing layer. A method on a film; or a method of applying the above-mentioned adhesive composition onto a polarizing film, drying and removing a polymerization solvent or the like to form an adhesive layer on the polarizing film, and the like. Further, the application of the adhesive may be carried out by appropriately adding one or more solvents other than the polymerization solvent.

It is preferred to use a polyfluorene stripping liner for the release treated separator. In the step of applying the adhesive composition of the present invention to the lining material and drying it to form an adhesive layer, a suitable and appropriate method can be employed as a method of drying the adhesive. It is desirable to use a method of heating and drying the above coating film. The heating and drying temperature is preferably from 40 ° C to 200 ° C, more preferably from 50 ° C to 180 ° C, and particularly preferably from 70 ° C to 170 ° C. By setting the heating temperature within the above range, an adhesive having excellent adhesive properties can be obtained.

The drying time can be appropriately selected for a suitable period of time. The drying time is preferably from 5 seconds to 20 minutes, more preferably from 5 seconds to 10 minutes, and particularly preferably from 10 seconds to 5 minutes.

Further, an anchor layer may be formed on the surface of the polarizing film, or various adhesion treatments such as corona treatment and plasma treatment may be applied to form an adhesive layer. Further, the surface of the adhesive layer can be easily treated.

Various methods can be employed for the formation of the adhesive layer. Specific examples thereof include roll coating, contact roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip coating, bar coating, doctor coating, and air knife coating. Method, curtain type coating method, lip coating method, extrusion coating method using a die coater or the like.

The thickness of the above-mentioned adhesive layer is not particularly limited and is, for example, about 1 to 100 μm. It should be 2~50μm, preferably 2~40μm, more preferably 5~35μm.

The surface resistivity (B) of the adhesive layer stored in a humidified environment at 60 ° C / 90% RH for 500 hours, and the change rate of the surface resistance value (A) before storage in the humidified environment (B) ×100/A) is preferably 700% or less, preferably 500% or less, more preferably 400% or less, and particularly preferably 300% or less.

Further, the surface resistivity (A) of the adhesive layer before storage in the humidifying environment is preferably 1.0 × 10 ¹¹ Ω / □ or less, more preferably 8.0 × 10 ¹⁰ Ω / □ or less, and 5.0 × 10 ^{It is} especially preferable to be ¹⁰ Ω/□ or less.

When the aforementioned adhesive layer is exposed, the adhesive-treated sheet (separator) can also be used to protect the adhesive layer until it is applied.

The constituent material of the separator may, for example, be a plastic film such as polyethylene, polypropylene, polyethylene terephthalate or polyester film, or a porous material such as paper, cloth or non-woven fabric, a mesh, a foamed sheet or a metal. A suitable sheet such as a foil or the like, or the like, is preferably a plastic film from the viewpoint of excellent surface smoothness.

The plastic film is not particularly limited as long as it can protect the adhesive layer, and examples thereof include a polyethylene film, a polypropylene film, a polybutene film, a polypentadiene film, a polymethylpentene film, and a polyvinyl chloride. Film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene-vinyl acetate film, and the like.

The thickness of the separator is usually 5 to 200 μm, preferably about 5 to 100 μm. The release member may be subjected to mold release and antifouling treatment using a polyfluorene-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, cerium oxide powder, etc., and a coating type, Antistatic treatment such as kneading type or vapor deposition type. In particular, by appropriately performing a release treatment such as polyfluorination treatment, long-chain alkyl treatment, or fluorine treatment on the surface of the separator, the peeling property from the adhesion of the pressure-sensitive adhesive layer can be further improved.

Further, the release-treated sheet used in the production of the above-mentioned polarizing film with an adhesive layer can be directly used as a separator of a polarizing film with an adhesive layer, and can be simplified in terms of process.

The polarizing film can be used with a transparent protective film only on one side of the polarizing member.

The polarizer is not particularly limited, and various polarizers can be used. The polarizing material may have a dichroic property of adsorbing iodine or a dichroic dye on a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, or an ethylene-vinyl acetate copolymer-based partially saponified film. The material is uniaxially stretched, and a polyene-based alignment film such as a dehydrated material of polyvinyl alcohol or a dehydrochlorinated product of polyvinyl chloride is used. Among these, a polarizing member composed of a polyvinyl alcohol-based film and a dichroic material such as iodine is preferable. The thickness of the polarizing members is not particularly limited, and is generally about 80 μm or less.

The polarizing member which is uniaxially stretched with a iodine-based film of a polyvinyl alcohol-based film can be dyed by, for example, immersing a polyvinyl alcohol-based film in an aqueous solution of iodine, and is formed by stretching 3 to 7 times the original length. to make. It may be immersed in boric acid or an aqueous solution containing potassium iodide such as zinc sulfate or zinc chloride as needed. Further, it is also possible to immerse the polyvinyl alcohol-based film in water for washing with water before dyeing. By washing the polyvinyl alcohol-based film with water, the dirt and the anti-caking agent on the surface of the polyvinyl alcohol-based film can be washed, and the polyvinyl alcohol-based film can be swollen to prevent unevenness such as uneven dyeing. The extension may be carried out after dyeing with iodine, or may be dyed while stretching, or may be dyed with iodine after extension. It can also be extended in an aqueous solution such as boric acid or potassium iodide or in a water bath.

The thickness of the polarizer is preferably 12 μm or less, more preferably 10 μm or less, more preferably 8 μm or less, more preferably 7 μm or less, and particularly preferably 6 μm or less from the viewpoint of thickness reduction and suppression of occurrence of so-called through cracks. On the other hand, the thickness of the polarizer is 2 μm or more, and more preferably 3 μm or more. The thin polarizer has a small thickness difference, is excellent in visibility, and has small dimensional change, so it is excellent in durability against thermal punching.

Representative examples of the thin polarizer include those described in Japanese Patent Laid-Open No. 51-069644, Japanese Patent Laid-Open No. 2000-338329, No. WO2010/100917, and PCT/JP2010/001460, or Japanese Patent. A thin polarizing layer of the specification of 2010-269002 or the specification of Japanese Patent Application No. 2010-263692. The thin polarizing layer can be obtained by a method comprising the steps of: extending a layer of a polyvinyl alcohol-based resin (hereinafter also referred to as a PVA-based resin) and a resin substrate for stretching in a state of a laminate; Dyeing step. According to this production method, even if the PVA-based resin layer is thin, it can be extended by the resin substrate for stretching and can be stretched without causing breakage such as elongation.

In the method of the step of performing the step of stretching and the step of dyeing in the state in which the thin polarizing layer is stretched in the state of the laminated body, it is preferable to use, for example, WO2010/100917 from the viewpoint of improving the polarizing performance at a high magnification. The manual of the publication, the specification of PCT/JP2010/001460, or the method described in the specification of Japanese Patent Application No. 2010-269002 or the specification of Japanese Patent Application No. 2010-263692, which comprises the step of extending in an aqueous solution of boric acid. It is particularly preferable to use a method as described in the specification of Japanese Patent Application No. 2010-269002 or the specification of Japanese Patent Application No. 2010-263692, which includes a step of performing an auxiliary air extension before extending in an aqueous boric acid solution. Winner.

The thin high-performance polarizing layer described in the above-mentioned specification of PCT/JP2010/001460 is formed of a PVA-based resin integrally formed of a dichroic material and has a thickness of 7 μm or less, and is thin. The high functional polarizing layer has an optical property of a single transmittance of 42.0% or more and a degree of polarization of 99.95% or more.

The thin high-performance polarizing layer can be produced by forming a PVA-based resin layer on a resin substrate having a thickness of at least 20 μm by applying and drying a PVA-based resin, and impregnating the formed PVA-based resin layer. In the dyeing liquid of the dichroic substance, the dichroic substance is adsorbed to the PVA-based resin layer, and the PVA-based resin layer to which the dichroic substance has been adsorbed is integrally formed with the resin substrate in the boric acid aqueous solution to extend the total stretching ratio. It is more than 5 times the original length.

Further, the thin high-performance polarizing layer can be produced by a method for producing a laminate film comprising a thin high-performance polarizing layer in which a dichroic substance is aligned, the method comprising the steps of: forming a laminated film; The laminate film includes a resin substrate having a thickness of at least 20 μm and a PVA-based resin layer, and the PVA-based resin layer is formed by coating and drying an aqueous solution containing a PVA-based resin to form a single surface of the resin substrate; In the adsorption step, the laminate film including the resin substrate and the PVA-based resin layer formed on one surface of the resin substrate is immersed in the dyeing liquid containing the dichroic material to form the laminate film. The PVA-based resin layer adsorbs the dichroic material; the stretching step is carried out in the aqueous boric acid solution, and the laminated film including the PVA-based resin layer having the adsorbed dichroic material is extended to have a total stretching ratio of 5 times or more the original length; And a step of producing a laminate film which is formed on one side of the resin substrate by integrally extending the PVA-based resin layer to which the dichroic material has been adsorbed and the resin substrate In the thin high-performance polarizing layer, the thin high-performance polarizing layer is composed of a PVA-based resin layer in which a dichroic substance is aligned, has a thickness of 7 μm or less, and has a single transmittance of 42.0% or more and a degree of polarization of 99.95. Optical properties above %.

In the present invention, as described above, the polarizing film having the adhesive layer can be used as a polarizing member having a thickness of 12 μm or less: a polarizing layer of a continuous base composed of a PVA resin having a dichroic substance aligned therebetween. Further, the laminate comprising the polyvinyl alcohol-based resin layer formed on the thermoplastic resin substrate is extended by a two-stage extending step consisting of extending in the air and extending in boric acid water. The thermoplastic resin substrate is preferably a non-crystalline ester-based thermoplastic resin substrate or a crystalline ester-based thermoplastic resin substrate.

The thin polarizing layer of the above-mentioned Japanese Patent Application No. 2010-269002 or the specification of Japanese Patent Application No. 2010-263692 is a polarizing layer of a continuous base composed of a PVA resin having a dichroic substance aligned, and includes The layered body of the PVA-based resin layer formed on the amorphous ester-based thermoplastic resin substrate is stretched by a two-stage stretching step consisting of extending in the air and extending in boric acid water to have a thickness of 12 μm or less. When the monomer transmittance is T and the degree of polarization is P, the thin polarizing layer is preferably formed to satisfy P>-(10 ^0.929T-42.4 -1)×100 (but T<42.3), and P≧99.9 (only) Optical properties of the conditions of T≧42.3).

Specifically, the above-mentioned thin polarizing layer can be produced by a manufacturing method of a thin polarizing layer comprising the following steps: a step of forming an extended intermediate product, which is a non-crystalline ester-based thermoplastic resin substrate formed on a continuous base material. The PVA-based resin layer is stretched in the air at a high temperature to thereby form an extended intermediate product composed of the aligned PVA-based resin layer; and the step of producing a colored intermediate product is such that the extended intermediate product adsorbs the dichroic substance, thereby generating a colored intermediate product comprising a PVA-based resin layer in which a dichroic substance (preferably iodine or a mixture of iodine and an organic dye) is aligned; and a step of forming a polarizing layer, wherein the colored intermediate product is extended in boric acid water, whereby A polarizing layer having a thickness of 12 μm or less composed of a PVA-based resin layer in which a dichroic substance is aligned is formed.

In the production method, the total stretching ratio of the PVA-based resin layer which is formed by stretching in the air at a high temperature and extending in boric acid water to the amorphous ester-based thermoplastic resin substrate is preferably 5 times or more. The liquid temperature of the boric acid aqueous solution for extending the boric acid water can be set to 60 ° C or higher. Before the coloring intermediate product is extended in the aqueous boric acid solution, it is preferred to carry out the insoluble treatment on the colored intermediate product, and in this case, it is preferred to carry out the immersion of the colored intermediate product in an aqueous boric acid solution having a liquid temperature of not more than 40 °C. The amorphous ester-based thermoplastic resin substrate can be prepared by comprising a polyethylene terephthalate copolymer obtained by copolymerizing isononic acid and polyethylene terephthalate obtained by copolymerizing cyclohexane dimethanol. The diester copolymer or other copolymerized polyethylene terephthalate amorphous polyethylene terephthalate copolymer is preferably composed of a transparent resin, and its thickness can be set as a film-forming PVA system. The thickness of the resin layer is 7 times or more. Further, the stretching ratio of the high-temperature extension in the air is preferably 3.5 times or less, and the extension temperature of the high-temperature extension in the air is preferably a glass transition temperature of the PVA-based resin or more, specifically, a range of 95 ° C to 150 ° C. When the high-temperature extension in the air is carried out by uniaxial stretching at the free end, the total stretching ratio of the PVA-based resin layer formed on the amorphous ester-based thermoplastic resin substrate is preferably 5 times or more and 7.5 times or less. In the case where the high-temperature extension in the air is carried out by uniaxial stretching at the fixed end, the total stretch ratio of the PVA-based resin layer formed on the amorphous ester-based thermoplastic resin substrate is preferably 5 times or more and 8.5 times or less. More specifically, the thin polarizing layer can be produced by the following method.

A substrate of a continuous binder of isophthalic acid copolymerized polyethylene terephthalate (amorphous PET) obtained by copolymerization of 6 mol% of isophthalic acid was prepared. The glass transition temperature of the amorphous PET was 75 °C. A laminate comprising a continuous PET base material and a polyvinyl alcohol (PVA) layer was produced as follows. Incidentally, the glass transition temperature of PVA is 80 °C.

A 200 μm thick amorphous PET substrate and a PVA aqueous solution having a concentration of 1000 or more and a saponification degree of 99% or more of PVA powder dissolved in water were prepared. Next, the PVA aqueous solution was applied to a 200 μm thick amorphous PET substrate and dried at a temperature of 50 to 60 ° C to obtain a laminate having a 7 μm thick PVA layer formed on the amorphous PET substrate. .

A laminate having a 7 μm thick PVA layer was subjected to the following steps of a two-stage extension step including air-assisted extension and boric acid water extension to produce a thin, high-performance polarizing layer having a thickness of 3 μm. The layered body including the 7 μm thick PVA layer was integrally extended with the amorphous PET substrate by the air assisted extension step of the first stage to form an extended laminate including a 5 μm thick PVA layer. Specifically, the extended laminated body is an extension device provided by placing a laminate body including a 7 μm thick PVA layer in an oven, and uniaxially extending through the free end to a stretching ratio of 1.8 times, and the oven system is set to 130. °C extended temperature environment. By this stretching treatment, the PVA layer contained in the extended laminated body was converted into a 5 μm thick PVA layer in which the PVA molecules were aligned.

Next, by using a dyeing step, iodine is adsorbed on the 5 μm thick PVA layer of the PVA molecules to form a colored layered body. Specifically, the colored laminated body is obtained by immersing the extended laminated body in a dyeing liquid containing iodine and potassium iodide at a liquid temperature of 30 ° C for any time to form a PVA which is a finally formed high-performance polarizing layer. The monomer transmittance of the layer is 40 to 44%, whereby iodine is adsorbed to the PVA layer contained in the extended laminate. In this step, the dyeing liquid is water as a solvent, and the iodine concentration is in the range of 0.12 to 0.30% by weight, and the potassium iodide concentration is in the range of 0.7 to 2.1% by weight. The concentration ratio of iodine to potassium iodide is 1 to 7. Incidentally, potassium iodide must be present when iodine is dissolved in water. More specifically, the colored laminate is formed by immersing the extended laminate in a dyeing solution having an iodine concentration of 0.30% by weight and a potassium iodide concentration of 2.1% by weight for 60 seconds to form a PVA molecule with a 5 μm thick PVA layer adsorbing iodine. body.

Further, by the step of extending the boric acid water in the second stage, the colored layered body and the amorphous PET substrate are further integrally extended to form an optical film layered body including a 3 μm thick PVA layer constituting the high functional polarizing layer. Specifically, the optical film laminate is an extension device provided in the processing apparatus, and is uniaxially extended by a free end to have a stretching ratio of 3.3 times, and the processing apparatus is set to contain boric acid and A boric acid aqueous solution having a liquid temperature range of 60 to 85 ° C of potassium iodide. More specifically, the liquid temperature of the aqueous boric acid solution was 65 °C. Further, the boric acid content was 4 parts by weight based on 100 parts by weight of water, and the potassium iodide content was 5 parts by weight based on 100 parts by weight of water. In this step, the colored layer body having the adjusted iodine adsorption amount is first immersed in the boric acid aqueous solution for 5 to 10 seconds. Then, the colored layered body is directly passed through a plurality of sets of rolls having different rotation speeds of the stretching device provided in the processing apparatus, and the free end uniaxially extends to a stretching ratio of 3.3 times for 30 to 90 seconds. By this stretching treatment, the PVA layer contained in the colored layered body was converted into a 3 μm-thick PVA layer in which the adsorbed iodine was highly aligned in a single direction in the form of a polyiodide complex. The PVA layer can constitute a high-performance polarizing layer of the optical film laminate.

Although it is not a necessary step in the production of the optical film laminate, it is preferable to remove the optical film laminate from the aqueous solution of boric acid by a washing step with potassium iodide solution and adhere to the 3 μm thick film formed on the amorphous PET substrate. Boric acid on the surface of the PVA layer. Then, the washed optical film laminate was dried by a drying step using a warm air of 60 °C. In addition, the washing step is a step for solving the appearance defect such as boric acid precipitation.

Similarly, although it is not a necessary step in the production of the optical film laminate, the adhesion can be applied to the 3 μm thick film which has been formed on the amorphous PET substrate by the bonding and/or transfer step. On the surface of the PVA layer, a (meth)acrylic resin film having a lactone ring structure having a thickness of 40 μm was bonded, and then the amorphous PET substrate was peeled off to transfer a 3 μm thick PVA layer to a lactone-containing layer having a thickness of 40 μm. On the (meth)acrylic resin film of the ring structure.

[Other Steps] In addition to the above steps, the above-described method of manufacturing the thin polarizing layer may include other steps. Other steps include, for example, an insolubilization step, a crosslinking step, a drying (adjustment of moisture content) step, and the like. Other steps can be performed at any and appropriate point in time. The above insoluble step is represented by immersing the PVA-based resin layer in an aqueous boric acid solution. The water resistance of the PVA-based resin layer can be imparted by performing the insolubilization treatment. The concentration of the aqueous boric acid solution is preferably from 1 part by weight to 4 parts by weight based on 100 parts by weight of water. The liquid temperature of the insoluble bath (aqueous boric acid solution) is preferably from 20 ° C to 50 ° C. The insoluble step is preferably carried out after the production of the laminate, before the dyeing step or the water stretching step. The crosslinking step is represented by immersing the PVA-based resin layer in an aqueous boric acid solution. By performing the crosslinking treatment, the PVA-based resin layer can be imparted with water resistance. The concentration of the aqueous boric acid solution is preferably from 1 part by weight to 4 parts by weight based on 100 parts by weight of water. Further, when the crosslinking step is carried out after the above dyeing step, it is more preferable to blend iodide. By mixing the iodide, elution of iodine adsorbed to the PVA-based resin layer can be suppressed. The amount of the iodide blended is preferably from 1 part by weight to 5 parts by weight per 100 parts by weight of the water. Specific examples of the iodide are as described above. The liquid temperature of the crosslinking bath (aqueous boric acid solution) is preferably from 20 ° C to 50 ° C. The crosslinking step is preferably carried out before the step of extending the second boric acid water described above. In a preferred embodiment, the dyeing step, the crosslinking step, and the second boric acid water extending step are sequentially performed.

As the material constituting the transparent protective film, for example, a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, moisture resistance, isotropicity, and the like can be used. Specific examples of such a thermoplastic resin include a cellulose resin such as triacetonitrile cellulose, a polyester resin, a polyether oxime resin, a polyfluorene resin, a polycarbonate resin, a polyamide resin, and a polyimide resin. A polyolefin resin, a (meth)acrylic resin, a cyclic polyolefin resin (northene-based resin), a polyarylate resin, a polystyrene resin, a polyvinyl alcohol resin, and a mixture thereof. The transparent protective film may contain one or more optional and appropriate additives. The additives may, for example, be ultraviolet absorbers, antioxidants, slip agents, plasticizers, mold release agents, anti-colorants, flame retardants, nucleating agents, antistatic agents, pigments, colorants, and the like. In the transparent protective film, the thermoplastic resin is preferably contained in an amount of from 50 to 100% by weight, preferably from 50 to 99% by weight, more preferably from 60 to 98% by weight, particularly preferably from 70 to 97% by weight. In the transparent protective film, when the content of the thermoplastic resin is 50% by weight or less, the thermoplastic resin may not sufficiently exhibit the high transparency and the like which it originally has.

Further, the transparent protective film is bonded to one side of the polarizer through the adhesive layer. An adhesive can be used for the subsequent treatment of the polarizing member and the transparent protective film. Examples of the adhesive agent include an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, an ethylene-based latex, and an aqueous polyester. The above-mentioned adhesive is usually used as an adhesive composed of an aqueous solution, and usually contains 0.5 to 60% by weight of a solid component. In addition to the above, examples of the adhesive for the polarizer and the transparent protective film include an ultraviolet curable adhesive, an electron beam hardening adhesive, and the like. The adhesive for an electron beam hardening type polarizing film can exhibit appropriate adhesion to the above various transparent protective films. Further, the adhesive used in the present invention may contain a metal compound filler.

Further, the polarizing film may be laminated with other optical films. Examples of the other optical film include a reflection plate or a reverse transmission plate, a retardation film (including a wavelength plate of 1/2 or 1/4 or the like), a viewing angle compensation film, a brightness enhancement film, and the like, and can also be used to form an optical layer of a liquid crystal display device or the like. By. These may be used for laminating one or more layers on the aforementioned polarizing film in practical use.

The optical film in which the optical layer is laminated on the polarizing film can be formed by laminating in a separate manner in the manufacturing process of a liquid crystal display device, etc., but the optical film is laminated in advance to have excellent quality stability and assembly work. There is an advantage that the manufacturing steps of the liquid crystal display device or the like can be improved. An appropriate bonding means such as an adhesive layer can be used for lamination. When the polarizing film is bonded to another optical layer, the optical axes can be set to an appropriate arrangement angle in accordance with the desired phase difference characteristics.

The polarizing film (B) of the polarizing film with an adhesive layer of the present invention stored in a humidified environment at 60 ° C / 90% RH for 500 hours, and the degree of polarization (A) before storage in the humidified environment The amount of change (AB) is preferably within 0.05, more preferably within 0.04, and even more preferably within 0.03.

The polarizing film with an adhesive layer of the present invention can be suitably used for forming various image display devices such as liquid crystal display devices. The formation of the liquid crystal display device can be performed in the past. In other words, the liquid crystal display device is generally formed by appropriately assembling a display panel such as a liquid crystal cell, a polarizing film with an adhesive layer, a component such as an illumination system, and the like, and mounting the driving circuit or the like. There is no particular limitation on the use of the optical film with an adhesive layer of the present invention, and it can be conventionally known. For the liquid crystal cell, for example, a liquid crystal cell of any type such as a TN type, an STN type, a π type, a VA type, or an IPS type can be used.

A liquid crystal display device in which a polarizing film with an adhesive layer is disposed on one side or both sides of a display panel such as a liquid crystal cell, or a liquid crystal display device in which an illumination system uses a backlight or a reflector can be formed. At this time, the polarizing film of the adhesive layer of the present invention may be disposed on one side or both sides of the display panel such as a liquid crystal cell. When the optical film is disposed on both sides, the same may be the same or different. Further, when the liquid crystal display device is formed, one or two or more layers such as a diffusion layer, an anti-glare layer, an anti-reflection film, a protective plate, a tantalum array, a lens array sheet, a light-diffusing sheet, and a backlight may be disposed at appropriate positions. Suitable parts such as pieces. Example

Hereinafter, the present invention will be specifically described by examples, but the present invention is not limited by the examples. As for the weight and the percentage of each case, the weight basis. Hereinafter, room temperature conditions which are not specifically defined are 23 ° C and 65% RH.

<Measurement of Weight Average Molecular Weight of (Meth)Acrylic Polymer> The weight average molecular weight of the (meth)acrylic polymer is measured by GPC (gel permeation chromatography).・Analytical device: Tosoh (Tosoh) company, HLC-8120GPC. Pipe column: manufactured by Tosoh Corporation, G7000H _XL +GMH _XL +GMH _XL・Column size: each 7.8mmφ×30cm 90cm ・Tub column temperature: 40°C ・Flow rate: 0.8ml/min ・Injection amount: 100μl ・Solution solution : tetrahydrofuran detector: differential refractometer (RI) ・standard sample: polystyrene

<Preparation of Polarized Film> (Production of Polarizing Member) Amorphous isocyanic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 μm) substrate having a water absorption of 0.75% and a Tg of 75 ° C A corona treatment was applied to one side, and the coating was applied at 25 ° C on the corona-treated surface to contain polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and ethyl acetonitrile at a ratio of 9:1. An aqueous solution of a modified PVA (degree of polymerization: 1200, 4.6% saponification degree, saponification degree: 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gohsefimer Z200") and dried to form a thickness of 11 μm. A PVA-based resin layer was used to form a laminate. The obtained laminated body was uniaxially stretched 2.0 times in the longitudinal direction (longitudinal direction) between the rolls having different circumferential speeds in an oven at 120 ° C (air assisted extension treatment). Next, the laminate was immersed in an insoluble bath (boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with respect to 100 parts by weight of water) at a liquid temperature of 30 ° C for 30 seconds (insoluble treatment). Next, it was immersed in a dye bath at a liquid temperature of 30 ° C while adjusting the iodine concentration and the immersion time to bring the polarizing plate to a predetermined transmittance. In the present embodiment, this was immersed in an aqueous iodine solution obtained by blending 0.2 part by weight of iodine and 1.0 part by weight of potassium iodide with respect to 100 parts by weight of water for 60 seconds (dyeing treatment). Next, it was immersed in the cross-linking bath (the boric acid aqueous solution obtained by blending 3 parts by weight of potassium iodide and mixing 3 parts by weight of boric acid with respect to 100 parts by weight of water) at a liquid temperature of 30 ° C (crosslinking treatment). . Then, while immersing the layered body in a boric acid aqueous solution (mixing 4 parts by weight of boric acid with 5 parts by weight of water and mixing 5 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 70 ° C, the dispersion speed is different at the peripheral speed. The rolls are uniaxially stretched in the longitudinal direction (longitudinal direction) to a total stretch ratio of 5.5 times (water extension treatment). Thereafter, the laminate was immersed in a washing bath having a liquid temperature of 30° C. (an aqueous solution obtained by blending 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) (washing treatment). Through the above steps, an optical film laminate including a polarizing member having a thickness of 5 μm and a boric acid content of 16% was obtained.

<Preparation of an adhesive applied to a transparent protective film> 40 parts by weight of N-hydroxyethyl acrylamide (HEAA), 60 parts by weight of acryloyl phenylephrine (ACMO) and a photoinitiator "IRGACURE 819" (BASF) The company made 3 parts by weight to prepare an ultraviolet curing type adhesive.

(Preparation of a polarizing film) The UV-curable adhesive is applied to the surface of the polarizer of the optical film laminate, and is applied to an easy-processed surface of a (meth)acrylic resin film having a lactone ring structure having a thickness of 40 μm. After the corona treatment and bonding, the amorphous PET substrate was peeled off to produce a polarizing film using a thin polarizer. Hereinafter, it is referred to as a thin polarizing film.

<Preparation of Acrylic Polymer (A1)> In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a cooler, 80.3 parts of butyl acrylate, 0.5 parts of 4-hydroxybutyl acrylate, and acrylic acid were fed. A monomer mixture of 0.2 parts, 3 parts of N-vinylpyrrolidone and 16 parts of phenoxyethyl acrylate. Then, 0.15 parts of 2,2 ́-azobisisobutyronitrile as a polymerization initiator was fed together with 100 parts of the monomer mixture (solid content), and nitrogen gas was introduced while stirring slowly. After the nitrogen substitution, the liquid temperature in the flask was maintained at around 60 ° C, and polymerization reaction was carried out for 7 hours. Thereafter, ethyl acetate was added to the obtained reaction liquid to prepare a solution of the acrylic polymer (A1) having a solid concentration of 30% and a weight average molecular weight of 1.4 million.

<Preparation of Acrylic Polymers (A2) to (A12)> The monomer composition was changed to the polymerization conditions as shown in Table 1 in the preparation of the above acrylic polymer (A1), and the same method was used. A solution of the acrylic polymer (A2) to (A12) was prepared.

Example 1 (Preparation of the adhesive composition) Lithium bis(trifluoromethanesulfonyl) phthalimide (manufactured by Mitsubishi Material Electronic Co., Ltd.) was blended with respect to 100 parts of the solid content of the obtained acrylic polymer (A1) solution. 1 part, and blended with trimethylolpropane hexamethylene diisocyanate (manufactured by Mitsui Chemicals Co., Ltd., trade name "Takenate D-160N") 0.17 parts, benzophenone peroxide 0.25 parts, decane coupling agent (Shin-Etsu 0.2 parts by weight of a decane coupling agent (product name "A-100", manufactured by Amika Chemical Co., Ltd.) of 0.2 parts by weight and a decane-containing ketone group (manufactured by Kogaku Chemical Co., Ltd.) Acrylic adhesive solution.

(Preparation of polarizing film with an adhesive layer) Next, it is uniformly coated by a spray coater on the surface of a polyethylene terephthalate film (separation film) treated with a polyfluorene-based release agent. The above acrylic adhesive solution was applied and dried in an air circulating oven at 155 ° C for 1 minute to form an adhesive layer having a thickness of 20 μm on the surface of the separation film. Next, the adhesive layer formed on the separation film was transferred to the side of the polarizing layer of the polarizing member of the above-mentioned thin polarizing film to form a polarizing film with an adhesive layer.

Examples 2 to 9 and Comparative Examples 1 to 4 In the same manner as in Example 1, except that the type or amount of each component was changed as shown in Table 1 in the preparation of the adhesive composition in Example 1. A polarizing film with an adhesive layer was produced.

The polarizing film with the adhesive layer obtained in the above Examples and Comparative Examples was subjected to the following evaluation. The evaluation results are shown in Table 1.

<Measurement of the amount of change in the degree of polarization> The separation film of the polarizing film of the adhesive layer was peeled off and attached to a microscope slide (manufactured by Matsunami Glass Ind., Ltd., trade name "S200") using a bonding machine. . Next, autoclaving was performed for 15 minutes at 50 ° C and 0.5 MPa, and the polarizing film of the above-mentioned adhesive layer was completely adhered to the acrylic-free glass. Next, it was stored in a humidified environment of 60 ° C / 90% RH for 500 hours. The polarizing degree of the polarizing film before and after storage was measured using V7100 manufactured by JASCO Corporation. The amount of change in the degree of polarization was calculated by the following formula and evaluated according to the following criteria. Change amount ΔP = (polarization degree before storage) - (polarization degree after storage) (evaluation standard) ◎: 0 ≦ ΔP < 0.02 〇: 0.02 ≦ ΔP < 0.04 △: 0.04 ≦ ΔP < 0.05 ×: 0.05 ≦ ΔP

<Measurement of Change Rate of Surface Resistance Value> After peeling off the separation film of the polarizing film of the adhesive layer, the surface resistance value (Ω/□) of the surface of the adhesive was measured using MCP-HT450 manufactured by Mitsubishi Chemical Corporation. Further, after the polarizing film with the adhesive layer was stored in a humidified environment at 60 ° C / 90% RH for 500 hours, the surface resistance value of the surface of the adhesive was also measured in the same manner as above. The rate of change (%) of the surface resistance value was calculated by the following formula and evaluated according to the following criteria. Rate of change ΔR (%) = (surface resistance value after storage) × 100 / (surface resistance value before storage) (evaluation standard) ◎: 0 ≦ ΔR < 300 〇: 300 ≦ ΔR < 500 Δ: 500 ≦ ΔR < 700 ×: 700 ≦ ΔR

<Measurement of Haze> After peeling off the separation film of the polarizing film with the adhesive layer, the adhesive layer was measured using a haze meter (manufactured by Murakami Color Research Institute, HN-150) according to the method specified in JIS 7136. The haze (%) of the polarizing film. The polarizing film with an adhesive layer has a haze of preferably 3% or less, more preferably 1% or less.

[Table 1]

The compounds in Table 1 are as follows. BA: butyl acrylate 4HBA: 4-hydroxybutyl acrylate AA: Acrylic acid NVP: N-vinylpyrrolidone ACMO: N-propylene fluorenyl phenylephrine MMA: methyl methacrylate PEA: phenoxyethyl acrylate LiTFSi : Lithium bis(trifluoromethanesulfonyl) quinone imine (manufactured by Mitsubishi Material Electronic Co., Ltd.) EMPTFSi: ethylmethylpyrrolidinium-bis(trifluoromethanesulfonyl) quinone imine (manufactured by Tokyo Chemical Industry Co., Ltd.)

[Industrial Applicability] The polarizing film with an adhesive layer of the present invention can be used for an image display device such as a liquid crystal display (LCD) or an organic EL display device, either alone or in a laminated optical film.

Claims (12)

A polarizing film with an adhesive layer, comprising a polarizing film and an adhesive layer disposed on the polarizing film, wherein the polarizing film of the adhesive layer is characterized in that: the polarizing film has a transparent protective film only on one side of the polarizing member, The adhesive layer is provided on a side of the polarizer that does not have the transparent protective film; and the adhesive layer is formed of a (meth)acrylic polymer and an adhesive composition containing an alkali metal salt; The methyl) acrylic polymer contains a monomer (1) having a nitrogen atom and a carbon-carbon double bond as a monomer unit. The polarizing film of the adhesive layer of claim 1, wherein the alkali metal of the alkali metal salt has a bonding energy with the iodine anion (I ^- ) of 50 kcal/mol or more. The polarizing film of the adhesive layer of claim 1 or 2, wherein the alkali metal in the alkali metal salt is lithium. The polarizing film of the adhesive layer according to any one of claims 1 to 3, wherein the aforementioned monomer (1) has a mercaptoamine group. The polarizing film of the adhesive layer according to any one of claims 1 to 4, wherein the aforementioned monomer (1) has a hetero ring containing a nitrogen atom. The polarizing film with an adhesive layer according to any one of claims 1 to 5, wherein the (meth)acrylic polymer contains 0.1 to 10% by weight of the monomer (1) as a monomer unit. The polarizing film with an adhesive layer according to any one of claims 1 to 6, wherein the adhesive composition contains 0.01 to 5 parts by weight of an alkali metal salt based on 100 parts by weight of the (meth)acrylic polymer. The polarizing film with an adhesive layer according to any one of claims 1 to 7, wherein a rate of change of the surface resistance value (B) and the surface resistance value (A) of the adhesive layer (B×100/A) is 700. % or less, the surface resistance value (B) is a resistance value stored in a humidified environment of 60 ° C / 90% RH for 500 hours, and the surface resistance value (A) is a resistance value before being stored in the humidification environment. . The polarizing film of the adhesive layer of claim 8, wherein the surface resistivity (A) of the adhesive layer before storage in the humidifying environment is 1.0 × 10 ¹¹ Ω/□ or less. The polarizing film with an adhesive layer according to any one of claims 1 to 9, wherein the polarizing member has a thickness of 12 μm or less. The polarizing film with an adhesive layer according to any one of claims 1 to 10, wherein the polarizing film (B) and the degree of polarization (A) of the polarizing film with the adhesive layer are within 0.05, The degree of polarization (B) is a degree of polarization after storage for 500 hours in a humidified environment of 60 ° C / 90% RH, and the degree of polarization (A) is a degree of polarization before storage in the humidified environment. An image display apparatus characterized by using a polarizing film having at least one layer of an adhesive layer as claimed in any one of claims 1 to 11.