TWI761474B - Polarizing film with adhesive layer and image display device - Google Patents

Abstract

The object of the present invention is to provide a polarizing film with an adhesive layer, which is not easily reduced in antistatic function and polarization degree and has excellent transparency even when exposed to a humidified environment. The polarizing film with an adhesive layer of the present invention has a polarizing film and an adhesive layer disposed on the polarizing film. The polarizing film with an adhesive layer is characterized in that the polarizing film has a transparent protective film only on one side of the polarizer. , the above-mentioned adhesive layer is arranged on the side of the polarizer without the above-mentioned transparent protective film; and the above-mentioned adhesive layer is formed by an adhesive composition containing a (meth)acrylic polymer and an alkali metal salt; the above-mentioned The (meth)acrylic polymer contains a monomer having a nitrogen atom and a carbon-carbon double bond as a monomer unit.

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 the adhesive layer of the polarizing film. Furthermore, the present invention relates to a liquid crystal display device, an organic EL display device, and an image display device such as a PDP using the polarizing film having the above-mentioned adhesive layer.

Background of the Invention

In liquid crystal display devices and the like, it is essential to arrange polarizing elements on both sides of a liquid crystal cell from the viewpoint of the image forming method, and polarizing films are generally attached. When attaching the above-mentioned polarizing film to a liquid crystal cell, an adhesive is usually used. In addition, in order to reduce the loss of light, the polarizing film and the liquid crystal cell are usually adhered with adhesives. In this case, a polarizing film with an adhesive layer in which the adhesive is pre-disposed in the form of an adhesive layer on one side of the polarizing film is generally used, because it does not require a drying step when fixing the polarizing film, etc. advantage. In addition, a release film is usually attached to the adhesive layer of the polarizing film with the adhesive layer.

When manufacturing a liquid crystal display device, when the aforementioned 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 may be Peel off and generate static electricity. The resulting static electricity may affect the alignment of the liquid crystal layer inside the liquid crystal display device, resulting in defects. In addition, the liquid crystal display device may be quiet when in use. Uneven display caused by electricity. Although the generation of static electricity can be suppressed by, for example, forming an antistatic layer on the outer surface of the polarizing film, the effect is small, and there is a problem that the generation of static electricity cannot be fundamentally prevented. Therefore, in order to suppress the generation of static electricity from its fundamental position, it has been sought to impart an antistatic function to the adhesive layer. As a means of imparting an antistatic function to an adhesive layer, for example, blending an ionic compound with an adhesive for forming the adhesive layer has been proposed (Patent Documents 1 to 3). Specifically, Patent Document 1 proposes an adhesive composition for optical films in which an alkali metal salt and/or an organic cation-anion salt is blended. Patent Document 2 proposes an adhesive composition containing an onium-anion and an alkali metal salt as a raw material for an adhesive layer of a polarizing film with an adhesive layer. Patent Document 3 proposes an adhesive composition containing an alkali metal salt as a raw material for an adhesive layer of an adhesive polarizing plate.

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2015-199942

Patent Document 2: Japanese Patent Laid-Open No. 2014-48497

Patent Document 3: Japanese Patent Laid-Open No. 2012-247574

Summary of Invention

For the polarizing film with an adhesive layer, sometimes only a transparent protective film is provided on one side of the polarizer, and no transparent protective film is provided on the other side, but an adhesive layer is provided with an adhesive layer. film. Since the polarizing film with the adhesive layer only has a transparent protective film on one side, it is Compared with the case where the transparent protective film is provided on both sides, the cost of the layer of the transparent protective film can be reduced. However, alkali metal salts, particularly lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), described in Patent Documents 1 to 3 are blended into the adhesive layer of the polarizing film with the adhesive layer. When lithium-organic anion salts such as lithium-organic anion salts are used as ionic compounds, if the polarizing film with the adhesive layer is exposed to a humidified environment, a new problem will arise that the antistatic function of the adhesive layer is lowered. On the other hand, when an organic cation (onium)-anion salt is mixed in the adhesive layer of the polarizing film with the adhesive layer, if the polarizing film with the adhesive layer is exposed to a humidified environment, the polarized light will be polarized. The parts will deteriorate, causing problems such as so-called fading, a decrease in the degree of polarization, and the like.

In addition, in order to improve the antistatic function of the adhesive layer of the polarizing film with the adhesive layer, if the content of the ionic compound in the adhesive layer is increased, the adhesive layer will be cloudy, resulting in a decrease in transparency and adhesion. The problem of lowering the optical properties of the polarizing film of the adhesive layer.

The object of the present invention is to provide a polarizing film with an adhesive layer, which is not easily reduced in antistatic function and polarization degree and has excellent transparency even when exposed to a humidified environment.

Moreover, the objective of this invention is to provide the image display apparatus which used the polarizing film of the said adhesive bond layer.

In order to solve the above-mentioned problems, the inventors of the present invention made careful and repeated investigations, and as a result, they found the following polarizing film with an adhesive layer, and finally completed the present invention.

That is, the present invention relates to a polarizing film with an adhesive layer, which has a polarizing film and an adhesive layer provided on the polarizing film, and the adhesive layer is attached to the polarizing film. The polarizing film of the adhesive layer is characterized in that: the polarizing film only has a transparent protective film on one side of the polarizer, the adhesive layer is arranged on the side of the polarizer without the transparent protective film; and the adhesive layer is a Formed from an adhesive composition containing a (meth)acrylic polymer and an alkali metal salt; the (meth)acrylic polymer contains a monomer (1) having a nitrogen atom and a carbon-carbon double bond as a single body unit.

When the adhesive layer of the polarizing film adhering to the adhesive layer is mixed with alkali metal salts such as lithium-organic anion salts, if the polarizing film adhering to the adhesive layer is exposed to a humidified environment, the antistatic function of the adhesive layer will decrease, and the inventors believe that the reason is that the alkali metal salt will exhibit a strong interaction with the iodine in the polarizer, so if the adhesive layer is exposed to a humidified environment, the alkali metal salt in the adhesive layer will Since the polarizer side moves and exists locally, the surface resistance value of the adhesive layer is increased. Furthermore, it was found that by using a (meth)acrylic polymer in which a monomer (1) having a nitrogen atom and a carbon-carbon double bond was introduced by copolymerization as a base polymer of the adhesive layer, even if the adhesive layer was exposed In a humidified environment, the antistatic performance is not easy to decline. The reason for this is presumed as follows. The alkali metal salt in the adhesive layer is less prone to polarizing by the interaction between the (meth)acrylic polymer having the monomer (1) having nitrogen atom and carbon-carbon double bond and the alkali metal salt by copolymerization The member side is moved, thereby suppressing the local presence on the polarizer side, so that the increase of the surface resistance value of the adhesive layer is suppressed.

Moreover, due to the introduction of a nitrogen atom and a carbon-carbon double The (meth)acrylic polymer of the monomer (1) of the bond has a polar group, so it can improve the compatibility with the alkali metal salt, and even if the content of the alkali metal salt is increased, the adhesive layer is not easily cloudy, and the adhesive layer The transparency is not easy to decrease. Therefore, the fall of the optical characteristic of the polarizing film with an adhesive bond layer can be suppressed.

In addition, when the organic cation (onium)-anion salt is mixed in the adhesive layer, since the bonding energy between the organic cation (onium) ion and the iodide anion in the polarizer is low, the interaction is also small. Therefore, when the polarizing film with the adhesive layer is exposed to a humidified environment, the iodine in the polarizer will easily flow out to the outside (in the adhesive). It can be considered that the result is that the polarizer deteriorates and the degree of polarization decreases. The inventors of the present invention found that by mixing an alkali metal salt in the polarizing film with an adhesive layer, even if the polarizing film with an adhesive layer is exposed to a humidified environment, the polarizer is not easily deteriorated and the degree of polarization is not easily reduced . The reason for this is presumed as follows. Since the bonding energy between the alkali metal cation and the iodine anion in the polarizer is high, the isometric interaction is also large, and at the interface between the adhesive layer and the polarizer, the alkali metal cation can stabilize the iodine complex in the polarizer. Therefore, even if the polarizing film with the adhesive layer is exposed to a humidified environment, the iodine in the polarizer cannot easily flow out to the outside (in the adhesive). As a result, it is considered that the polarizer is less likely to deteriorate and the degree of polarization is less likely to decrease.

The bonding energy between the alkali metal in the aforementioned alkali metal salt and the iodide anion (I ⁻ ) is preferably above 50 kcal/mol, and is preferably lithium.

The aforementioned monomer (1) preferably has an amide group. Further, the monomer (1) preferably has a nitrogen atom-containing heterocyclic ring.

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

The aforementioned adhesive composition preferably contains an alkali metal salt in an amount of 0.01 to 5 parts by weight relative to 100 parts by weight of the (meth)acrylic polymer.

The change rate (B×100/A) of the surface resistance value (B) and the surface resistance value (A) of the aforementioned adhesive layer is preferably below 700%, and the surface resistance value (B) is stored at 60℃/90 The resistance value after 500 hours in a humidified environment of %RH, the surface resistance value (A) is the resistance value before storage in the above-mentioned humidified environment.

Moreover, it is preferable that the surface resistance value (A) of the said adhesive bond layer before storage in the said humidified environment is 1.0*10< ¹¹ > ohm/square or less.

The above-mentioned polarizing film with the adhesive layer can be used as a polarizer with a thickness of 12 μm or less.

In addition, the degree of polarization (B) and the degree of change (A-B) of the degree of polarization (A) of the polarizing film with the adhesive layer are preferably within 0.05, and the degree of polarization (B) is stored at 60°C/90%RH The degree of polarization (A) is the degree of polarization before storage in the humidified environment described above.

Furthermore, the present invention relates to an image display device characterized by using a polarizing film having at least one layer of the aforementioned adhesive layer.

The adhesive layer of the polarizing film with the adhesive layer of the present invention contains a (meth)acrylic polymer and an alkali metal salt into which a monomer (1) having a nitrogen atom and a carbon-carbon double bond is introduced by copolymerization. By combining these functions, it is possible to obtain a polarizing film with an adhesive layer which is not easily reduced in antistatic function and polarization degree and which is excellent in transparency even when exposed to a humidified environment. The aforementioned monomer (1) When it is a monomer having an amide group and a heterocyclic ring containing a nitrogen atom, and the alkali metal in the alkali metal salt is lithium, the effect of the present invention will be the highest.

Form for carrying out the invention

The adhesive composition for forming the adhesive layer of the adhesive layer-adhering polarizing film of the present invention contains a (meth)acrylic polymer as a base polymer. A (meth)acrylic-type polymer usually contains an alkyl (meth)acrylate as a monomer unit as a main component. In addition, (meth)acrylate means acrylate and/or methacrylate, and (meth) of this invention also has the same meaning.

As a (meth)acrylic-acid alkylester which comprises the main structure of a (meth)acrylic-type polymer, the carbon number of a linear or branched alkyl group is 1-18, for example. For example, the aforementioned alkyl group can be exemplified by methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, cyclohexyl, heptyl, 2-ethylhexyl, isooctyl, nonyl , decyl, isodecyl, dodecyl, isomyristyl, lauryl, tridecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, etc. These may be used alone or may be used in combination. The average carbon number of these alkyl groups is preferably 3-9.

As the monomer unit, the weight ratio of the alkyl (meth)acrylate is preferably 70% by weight or more in the weight ratio of the total constituent monomers (100% by weight) constituting the (meth)acrylic polymer. The weight ratio of the alkyl (meth)acrylate can be considered as the remainder of the nitrogen-containing monomer and other comonomers. It is preferable to set the weight ratio of the alkyl (meth)acrylate to the aforementioned range in order to secure the adhesiveness.

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

等含有N-(甲基)丙烯醯基的雜環單體；N-(甲基)丙烯醯基吡咯啶酮、N-(甲基)丙烯醯基哌啶酮、N-(甲基)丙烯醯基-ε-己內醯胺等含有N-(甲基)丙烯醯基的內醯胺系單體；N-乙烯基吡咯啶酮、N-乙烯基哌啶酮、N-乙烯基-ε-己內醯胺等含有N-乙烯基的內醯胺系單體；乙烯基吡

、乙烯基哌啶、乙烯基吡啶、乙烯基嘧啶、乙烯基哌

、乙烯基吡

、乙烯基吡咯、乙烯基咪唑、乙烯基

唑、乙烯基嗎福林等含雜環的乙烯基單體等。該等可單獨使用或可組合使用。其中，以使用(甲基)丙烯醯胺系單體、含N-(甲基)丙烯醯基的雜環單體、含N-(甲基)丙烯醯基的內醯胺系單體及含N-乙烯基的內醯胺系單體等含醯胺基的單體為佳，以含N-(甲基)丙烯醯基的內醯胺系單體及含N-乙烯基的內醯胺系單體等內醯胺系單體更佳，且含N-乙烯基的內醯胺系單體尤佳。 The monomer (1) is a compound containing a nitrogen atom and a polymerizable unsaturated double bond such as a (meth)acryloyl group and a vinyl group in the structure. Examples of the monomer (1) include maleimide-based monomers such as maleimide, N-cyclohexylmaleimide, and N-phenylmaleimide; N-(methyl) Acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, N-(meth)acryloyl-8-oxyocta Methylene succinimide and other succinimide monomers; N-methyl iconimide, N-ethyl iconimide, N-butyl iconimide, N-octyl Ikonimide, N-2-ethylhexyl Ikonimide, N-cyclohexyl Ikonimide, N-lauryl Ikonimide and other Ikonimide monomers; acrylonitrile , methacrylonitrile and other cyano (meth)acrylate monomers; (meth) amine ethyl acrylate, (meth) acrylate amine propyl ester, (meth) acrylic acid N,N-dimethylamine ethyl (meth)acrylic acid aminoalkyl monomers such as ester, (meth)acrylate tertiary butylamine ethyl ester, 3-(3-pyridyl)propyl (meth)acrylate, etc.; (meth)propylene Acrylamide, 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, aminomethyl (meth) acrylamide, amine ethyl (meth) acrylamide, mercaptomethyl (meth) acrylamide, mercaptoethyl (meth) acrylamide and other (meth)acrylamido monomers; N-(meth)acryloyl mofolin, N-(meth)acryloylpiperidine, N-(meth)acryloylpyridine

and other heterocyclic monomers containing N-(meth)acryloyl; N-(meth)acrylopyrrolidone, N-(meth)acrylopiperidone, N-(meth)propene Acrylo-ε-caprolactamide and other lactamide-based monomers containing N-(meth)acryloyl groups; N-vinylpyrrolidone, N-vinylpiperidone, N-vinyl-ε -lactam-based monomers containing N-vinyl such as caprolactam; vinylpyridine

, vinylpiperidine, vinylpyridine, vinylpyrimidine, vinylpiperidine

, vinylpyridine

, vinylpyrrole, vinylimidazole, vinyl

azoles, vinyl morpholin and other heterocyclic vinyl monomers, etc. These may be used alone or may be used in combination. Among them, (meth)acrylamide-based monomers, N-(meth)acrylamide-containing heterocyclic monomers, N-(meth)acrylamide-containing lactamide-based monomers, and N-(meth)acrylamide-containing N-vinyl lactamide-based monomers and other amide group-containing monomers are preferred, and N-(meth)acryloyl group-containing lactamide-based monomers and N-vinyl-containing lactamides are preferred. A lactamide-based monomer such as a system monomer is more preferred, and an N-vinyl group-containing lactamide-based monomer is particularly preferred.

From the viewpoint of suppressing the increase in the surface resistance value of the adhesive layer when the adhesive layer is exposed to a humidified environment, from the viewpoint of suppressing the decrease in polarization degree when the polarizing film with the adhesive layer is exposed to a humidified environment, and even if the adhesion is improved From the viewpoint that the content of the alkali metal salt in the agent layer can also maintain the transparency of the adhesive layer, the aforementioned weight ratio of the aforementioned monomer (1) is preferably 0.1 to 10% by weight, more preferably 1 to 5% by weight, 1 ~3 wt% is preferred. If the weight ratio of the nitrogen-containing monomer is less than 0.1% by weight, the surface resistance value of the adhesive layer tends to increase when the adhesive layer is exposed to a humidified environment, or the content of the alkali metal salt in the adhesive layer is increased. There is a tendency for the transparency of the adhesive layer to decrease easily. On the other hand, if the weight ratio of the nitrogen-containing monomer is greater than 10% by weight, the adhesion When the polarizing film of the adhesive layer is exposed to a humidified environment, the degree of polarization tends to decrease, and the reworkability tends to decrease.

In order to improve adhesion and heat resistance, one or more polymerizable functional groups having unsaturated double bonds such as (meth)acryloyl groups and vinyl groups may be introduced into the (meth)acrylic polymers by copolymerization. comonomer. Specific examples of the comonomer include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxybutyl (meth)acrylate. Hydroxyhexyl, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate or (4-hydroxymethylcyclohexyl)-methacrylic acid Hydroxyl-containing monomers such as esters; (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid and other carboxyl-containing monomers Monomers; acid anhydride group-containing monomers such as maleic anhydride and itonic anhydride; (meth)acrylic acid alkoxyalkyl groups such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate Monomers; sulfonic acid group-containing monomers such as styrene sulfonic acid or allyl sulfonic acid, sulfopropyl (meth)acrylate, (meth)acryloyloxynaphthalene sulfonic acid; 2-hydroxyethylacrylonitrile Phosphate group-containing monomers, such as phosphate esters, etc.

In addition, vinyl monomers such as vinyl acetate, vinyl propionate, styrene, and α-methyl styrene can also be used; epoxy-containing acrylic monomers such as glycidyl (meth)acrylate; ( Glycol-based acrylates such as polyethylene glycol meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate body; acrylate monomers such as tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, polysiloxane (meth)acrylate, etc. are used as modified monomers. Even Isoprene, butadiene, isobutylene, vinyl ether, etc. are mentioned.

In addition, the monomer which can be copolymerized other than the above-mentioned, the silane type monomer containing a silicon atom, etc. are mentioned. Silane-based monomers include, for example, 3-propenyloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-ethylene butylbutyltriethoxysilane, 8-vinyloctyltrimethoxysilane, 8-vinyloctyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-propene Acrylooxydecyltrimethoxysilane, 10-methacrylooxydecyltriethoxysilane and 10-acrylooxydecyltriethoxysilane, etc.

Moreover, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, bisphenol A diglycidyl can also be used Ether di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, neotaerythritol tri(meth)acrylate, neotaerythritol tetra (meth)acrylic acid ester, dipeotaerythritol penta(meth)acrylic acid ester, dipovaerythritol hexa(meth)acrylic acid ester, etc. (meth)acrylic acid ester product with polyhydric alcohol, etc. having 2 or more Polyfunctional monomers with unsaturated double bonds such as (meth)acryloyl and vinyl groups, or adding two or more (meth)acryloyl groups, vinyl groups to the backbone of polyester, epoxy, urethane, etc. Polyester (meth)acrylate, epoxy (meth)acrylate, urethane (meth)acrylate, etc., which are unsaturated double bonds as the same functional group as the monomer component, are used as comonomers.

Among these comonomers, from the viewpoint of adhesiveness and durability, a hydroxyl group-containing monomer and a carboxyl group-containing monomer are also suitably used. and can be used together Hydroxyl-containing monomers and carboxyl-containing monomers. These comonomers become reaction points with the crosslinking agent when the adhesive composition contains the crosslinking agent. Hydroxyl-containing monomers, carboxyl-containing monomers, etc. have good intermolecular reactivity with cross-linking agents, so they are suitable for improving the cohesion and heat resistance of the obtained adhesive layer. From the viewpoint of reproducibility, the hydroxyl group-containing monomer is suitable, and from the viewpoint of both durability and reproducibility, the carboxyl group-containing monomer is suitable.

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

The (meth)acrylic polymer of the present invention is usually used in the range of the weight average molecular weight of 500,000 to 3,000,000. In consideration of durability, especially heat resistance, a weight-average molecular weight of 700,000 to 2,700,000 is preferably used. It is more appropriate to use 800,000 to 2.5 million. If the weight average molecular weight is less than 500,000, it is unfavorable from the viewpoint of heat resistance. In addition, when the weight average molecular weight becomes larger than 3 million, a large amount of diluent solvent is required to adjust to the viscosity required for coating, which increases the cost and is not suitable. In addition, the weight average molecular weight means the value calculated by polystyrene conversion measured by GPC (Gel Permeation Chromatography; Gel Permeation Chromatography).

For the production of the (meth)acrylic polymer, known production methods such as solution polymerization, block polymerization, emulsion polymerization, and various radical polymerizations can be appropriately selected. Moreover, any of a random copolymer, a block copolymer, a graft copolymer, etc. may be sufficient as the obtained (meth)acrylic-type polymer.

In addition, in solution polymerization, a polymerization solvent such as ethyl acetate can be used. ethyl acetate, toluene, etc. For a specific example of solution polymerization, the reaction can be carried out by adding a polymerization initiator under an inert gas flow such as nitrogen, and usually at about 50 to 70° C. for about 5 to 30 hours.

The polymerization initiator, chain transfer agent, emulsifier, etc. used for radical polymerization are not particularly limited, and can be appropriately selected and used. In addition, the weight average molecular weight of a (meth)acrylic-type polymer can be controlled by the usage-amount of a polymerization initiator, a chain transfer agent, and reaction conditions, and its usage-amount can be adjusted suitably according to such kind.

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'-dimethylisobutylamidine), 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 and other persulfates, bis(2-ethylhexyl) peroxydicarbonate, bis(4-tertiary butylcyclohexyl) ) peroxydicarbonate, di-tertiary butyl peroxydicarbonate, tertiary butyl peroxyneodecanoate, tertiary hexyl peroxytrimethyl acetate, tertiary butyl peroxytrimethyl acetate , Dilauryl peroxide, di-n-octyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, bis(4-methylbenzyl) acyl) peroxide, dibenzyl peroxide, tertiary butyl perisobutyrate, 1,1-bis(tertiary hexyl peroxy) cyclohexane, tertiary butyl hydroperoxide, Peroxide-based initiators such as hydrogen peroxide; oxidation of peroxides combined with reducing agents such as the combination of persulfate and sodium bisulfite, the combination of peroxide and sodium ascorbate A reduction-based initiator, etc., are not limited thereto.

The aforementioned polymerization initiators can be used alone or in combination of two or more, but the overall content is preferably about 0.005 to 1 part by weight, more preferably about 0.02 to 0.5 part by weight, relative to 100 parts by weight of the monomer.

When, for example, 2'2-azobisisobutyronitrile is used as a polymerization initiator to produce a (meth)acrylic polymer having the aforementioned weight average molecular weight, the amount of the polymerization initiator to be used is 100% relative to the total amount of the monomer components. The weight part is preferably about 0.06 to 0.2 parts by weight, and more preferably about 0.08 to 0.175 parts by weight.

Examples of the chain transfer agent include lauryl mercaptan, glycidyl mercaptan, thioacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolic acid, 2,3-dimercapto- 1-Propanol, etc. The chain transfer agent may be used alone or in combination of two or more, but the entire content is about 0.1 part by weight or less with respect to 100 parts by weight of the total amount of the monomer components.

In addition, the emulsifier used in the emulsion polymerization includes, for example, sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, ammonium polyoxyethylene alkyl ether sulfate, and polyoxyethylene alkylene alkyl groups. Anionic emulsifiers such as sodium phenyl ether sulfate, polyoxyethylidene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, polyoxyethylene-polyoxyethylene Nonionic emulsifiers such as propyl block polymers, etc. These emulsifiers may be used alone or in combination of two or more.

In addition, as a reactive emulsifier, an emulsifier having a radically polymerizable functional group such as an acryl group and an allyl ether group is introduced. Specifically, Aqualon HS-10, HS-20, KH-10, BC-05, BC-10, BC-20 (all of the above are manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), ADEKA REASOAP SE10N (manufactured by Souden Chemical Co., Ltd.), etc. Since the reactive emulsifier is incorporated into the polymer chain after polymerization, it is preferable that the water resistance is good. The amount of the emulsifier used is 0.3 to 5 parts by weight relative to 100 parts by weight of the total amount of monomer components, and preferably 0.5 to 1 part by weight from the viewpoint 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, organic salts and inorganic salts of alkali metals can be used.

Examples of the alkali metal ions constituting the cation moiety of the alkali metal salts include respective ions such as lithium, sodium, potassium, and the like. From the viewpoint that the alkali metal ion can stabilize the iodine complex in the polarizer by increasing its interaction with the iodine anion in the polarizer, the bonding energy between the alkali metal ion and the iodide anion (I ^- ) is 50kcal/mol. The above is preferably the above, more preferably above 70kcal/mol, more preferably above 85kcal/mol, and particularly preferably above 105kcal/mol. From the above viewpoints, among the alkali metal ions, lithium ions having a bonding energy with an iodide anion (I ⁻ ) of 140.8 kcal/mol are preferable. In addition, when the aforementioned monomer (1) introduced by copolymerization in the aforementioned (meth)acrylic polymer is alkaline, once the (meth)acrylic polymer comes into contact with the polarizer, the polarizer will deteriorate, and prone to fading. However, if the alkali metal ion constituting the cation part of the alkali metal salt is lithium ion, since the iodine complex in the polarizer can be stabilized, the fading of the polarizer can be effectively suppressed.

The anion part of the alkali metal salt may be composed of organic matter or inorganic matter. In order to prevent the alkali metal salt in the adhesive layer from moving to the polarizer side, it is preferable that the anion part has a high bulk density. As the anion moiety 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 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 those shown in (4): (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 ), (only, p and q are integers from 1 to 10). In particular, the anion moiety containing a fluorine atom can be suitably used because an ionic compound having good ion dissociation property can be obtained. As the anion part constituting the inorganic salt, 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 represented by the aforementioned general formula (1), such as (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ and the like, from the viewpoint of the above-mentioned higher bulk density. Fluoroalkylsulfonyl)imide, ^and especially (trifluoromethanesulfonyl)imide represented by (CF ₃ SO ₂ ) ₂ N- is preferred.

Specific examples of the alkali metal organic salt include sodium acetate, sodium alginate, sodium lignosulfonate, sodium p-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, etc., among which 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. are preferred, Li(CF ₃ SO ₂ ) ₂ N, Li(C ₂ F ₅ SO ₂ ) ₂ N, Li(C ₄ F ₉ SO ₂ ) Fluorine-containing lithium imide salts such as ₂ N are more preferred, and (perfluoroalkylsulfonyl) imide lithium salts are particularly preferred.

Moreover, as an inorganic salt of an alkali metal, lithium perchlorate and lithium iodide are mentioned, for example.

In order to obtain the effect of the present invention, the content of the alkali metal salt in the adhesive composition of the present invention is preferably 0.01-5 parts by weight, more preferably 0.1-4.5 parts by weight, relative to 100 parts by weight of the (meth)acrylic polymer. Preferably, 0.5 to 4 parts by weight is particularly preferred. If the content of the alkali metal salt is less than 0.01 part by weight, it will be difficult to impart an antistatic function to the adhesive layer. On the other hand, when the content of the alkali metal salt exceeds 5 parts by weight, even if the above-mentioned (meth)acrylic polymer is used, the adhesive layer tends to become cloudy and the transparency of the adhesive layer tends to decrease.

The adhesive composition of the present invention may contain known organic cation (onium)-anion salts (such as those described in Japanese Patent Laid-Open No. 2014-048497) within the range that does not affect the effects of the present invention.

Furthermore, 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. As an organic crosslinking agent, an isocyanate type crosslinking agent, a peroxide type crosslinking agent, an epoxy type crosslinking agent, an imine type crosslinking agent, etc. are mentioned, for example. Polyfunctional metal chelates are covalently or coordinately bonded polyvalent metals and organic compounds. Examples of polyvalent metal atoms include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, Ti, and the like. Atoms that can be covalently or coordinately bonded in organic compounds include oxygen atoms, etc., and organic compounds include alkyl esters, alcohol compounds, Carboxylic acid compounds, ether compounds, ketone compounds, and the like.

The cross-linking agent is preferably an isocyanate-based cross-linking agent and/or a peroxide-based cross-linking agent. Examples of the compound of the isocyanate-based crosslinking agent include isocyanates such as toluene diisocyanate, chlorophenylene diisocyanate, tetramethylene diisocyanate, stubble diisocyanate, diphenylmethane diisocyanate, and hydrogenated diphenylmethane diisocyanate. Monomers, and isocyanate compounds, trimeric isocyanate compounds, and biuret compounds obtained by adding these isocyanate monomers to trimethylolpropane, etc., as well as polyether polyols or polyester polyols, acrylic polyols Urethane prepolymer isocyanates, etc., which are formed by addition reaction of alcohols, polybutadiene polyols, polyisoprene polyols, etc. Particularly preferred is a polyisocyanate compound, which is one selected from the group consisting of hexamethylene isocyanate, hydrogenated stubble diisocyanate, and isophorone diisocyanate, or a polyisocyanate compound derived therefrom. Here, the polyisocyanate compound selected from the group consisting of hexamethylene isocyanate, hydrogenated stubble diisocyanate and isophorone diisocyanate or the polyisocyanate compound derived therefrom includes: hexamethylene isocyanate, Hydrogenated stubble diisocyanate, isophorone diisocyanate, polyol-modified hexamethylene isocyanate, polyol-modified hydrogenated stubble diisocyanate, trimer hydrogenated stubble diisocyanate and polyol-modified isocyanurate phorone diisocyanate, etc. The reaction between the exemplified polyisocyanate compound and the hydroxyl group is preferable because the acid and base contained in the polymer can be rapidly advanced like a catalyst, which contributes to the crosslinking speed in particular.

As long as the peroxide-based cross-linking agent is heated or irradiated with light, it will generate free radical active species, so that the base polymer of the adhesive composition can progress. The cross-linked one can be used appropriately, but considering the workability and stability, it is advisable to use a peroxide with a half-life temperature of 80°C to 160°C for 1 minute, and preferably a peroxide with a temperature of 90°C to 140°C.

Useful peroxides include, for example, bis(2-ethylhexyl) peroxydicarbonate (1 minute half-life temperature: 90.6°C), bis(4-tert-butylcyclohexyl) peroxydicarbonate (1 minute Half-life temperature: 92.1°C), di-tertiary butyl peroxydicarbonate (1-minute half-life temperature: 92.4°C), tertiary butyl peroxyneodecanoate (1-minute half-life temperature: 103.5°C), trimethyl peroxide tertiary hexyl acetate (1 minute half-life temperature: 109.1°C), tertiary butyl peroxytrimethylacetate (1 minute half-life temperature: 110.3°C), dilauryl 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-ethylhexanoate (1-minute half-life temperature: 124.3 °C), bis(4-methylbenzyl) peroxide (1-minute half-life temperature: 128.2 °C), dibenzoyl peroxide (1-minute half-life temperature: 130.0 °C), perisobutyric acid tris butyl ester (1-minute half-life temperature: 136.1°C), 1,1-bis(tertiary hexylperoxy)cyclohexane (1-minute half-life temperature: 149.2°C), and the like. Among them, bis(4-tert-butylcyclohexyl)peroxydicarbonate (1-minute half-life temperature: 92.1°C), dilauryl peroxide (1 Minute half-life temperature: 116.4°C), dibenzoyl peroxide (1-minute half-life temperature: 130.0°C) and the like are suitable for use.

In addition, the half-life of peroxide is an index showing the decomposition rate of peroxide, and means the time until the residual amount of peroxide becomes half. Regarding the decomposition temperature required to reach the half-life at any time or at any time The half-life time at the desired temperature is described in the manufacturer's catalogue, etc., for example, in the "Organic Peroxide Catalogue 9th Edition (May 2003)" of NOF Corporation.

The usage amount of the crosslinking agent is preferably 0.01 to 20 parts by weight, more preferably 0.03 to 10 parts by weight, relative to 100 parts by weight of the (meth)acrylic polymer. In addition, if the crosslinking agent is less than 0.01 parts by weight, the cohesive force of the adhesive tends to be insufficient, and there is a possibility that bubbles may be generated during heating; on the other hand, if it is more than 20 parts by weight, the moisture resistance will be insufficient. , and peeling is likely to occur during reliability tests, etc.

The above-mentioned isocyanate-based cross-linking agent can be used alone or in combination of two or more, and the overall content is preferably 0.01 to 2 parts by weight of the aforementioned isocyanate-based cross-linking agent relative to 100 parts by weight of the (meth)acrylic polymer. It is composed of a combination agent, and preferably contains 0.02 to 2 parts by weight, and more preferably contains 0.05 to 1.5 parts by weight. A crosslinking agent may be appropriately contained in consideration of cohesive force and resistance to peeling during a durability test.

The aforementioned peroxides can be used alone or in combination of two or more, but the total content of the aforementioned peroxide is 0.01 to 2 parts by weight relative to 100 parts by weight of the aforementioned (meth)acrylic polymer, and It is preferable to contain 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 processability, reworkability, crosslinking stability, peelability, and the like.

In addition, 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 reaction site is taken out each time. After treatment, the adhesive composition was immersed in 10 ml of ethyl acetate, extracted with a shaker at 25° C. and 120 rpm for 3 hours, and then allowed to stand at room temperature for 3 days. Next, add 10 ml of acetonitrile, shake at 120 rpm for 30 minutes at 25°C, and inject about 10 μL of the extract obtained by filtration with a membrane filter (0.45 μm) into HPLC for analysis, which can be used as the amount of peroxide after the reaction treatment.

Furthermore, the adhesive composition of the present invention may contain a silane coupling agent. Durability can be improved by using a silane coupling agent. Specific examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and 3-glycidoxypropylmethyldisilane. Ethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and other epoxy-containing silane coupling agents; 3-aminopropyltrimethoxysilane, N-2-(aminoethyl) yl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylene)propylamine, N-phenyl-γ-aminopropyl Amine group-containing silane coupling agents such as trimethoxysilane; (meth)acryloyl group-containing Silane coupling agent; 3-isocyanatopropyl triethoxysilane and other silane coupling agents containing isocyanate groups, etc.

The aforementioned silane coupling agent can be used alone or in combination of two or more, but the overall content is preferably 0.001 to 5 parts by weight relative to 100 parts by weight of the aforementioned (meth)acrylic polymer. It is desirably 0.01 to 1 part by weight, more desirably 0.02 to 1 part by weight, and still more desirably 0.05 to 0.6 part by weight. It is the content which can improve durability and maintain the adhesive force to optical members, such as a liquid crystal cell, moderately.

In addition, the adhesive composition of the present invention can be blended with a polyether-modified polysiloxane compound. The polyether-modified polysiloxane compound disclosed in, for example, Japanese Patent Laid-Open No. 2010-275522 can be used.

The polyether-modified polysiloxane compound has a polyether skeleton, and at least one end has a reactive silicon group represented by the following general formula (1): General formula (1): -SiR _a M _3-a

(In the formula, R is a monovalent organic group having 1 to 20 carbon atoms as a substituent, M is a hydroxyl group or a hydrolyzable group, and a is an integer of 0 to 2; however, when there are multiple Rs, multiple R can be the same or different from each other; when there are multiple M, the multiple M can be the same or different from each other).

The aforementioned polyether-modified polysiloxane compound may be a compound represented by the following general formula (2): General formula (2): R _a M _3-a Si-XY-(AO) _n -Z

(In the formula, R is a monovalent organic group having 1 to 20 carbon atoms as a substituent, M is a hydroxyl group or a hydrolyzable group, and a is an integer of 0 to 2; however, when there are multiple Rs, multiple R can be the same or different from each other; when there are multiple M, the multiple M can be the same or different from each other; AO represents a linear or branched oxyalkylene with 1~10 carbon atoms, and n is 1~ 1700, represents the average added molar number of oxyalkylene; X represents linear or branched alkylene with carbon number 1~20; Y represents ether bond, ester bond, urethane bond or carbonate bond ; Z is a hydrogen atom, a hydrocarbon group with a monovalent carbon number of 1 to 10, a group represented by the following general formula (2A) or general formula (2B): general formula (2A): -Y ¹ -X-SiR _a M _3-a

(in the formula, R, M, X are the same as above; Y ¹ represents a single bond, -CO- bond, -CONH- bond or -COO- bond), general formula (2B): -Q{-(OA) _n - YX-SiR _a M _3-a } _m

(In the formula, R, M, X, Y are the same as the above; OA is the same as the above AO, n is the same as the above; Q is a hydrocarbon group with a valence of 2 or more carbon atoms of 1 to 10, and m is the same as the valence of the hydrocarbon group) ).

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

In addition, the adhesive composition of the present invention may also contain other known additives, such as polyether compounds of polyalkylene glycols such as polypropylene glycol, powders such as colorants, pigments, dyes, surfactants, Plasticizers, tackifiers, surface lubricants, levelers, softeners, antioxidants, antiaging agents, light stabilizers, UV absorbers, polymerization inhibitors, inorganic or organic fillers, metal powders, particulates , foil, etc. In addition, within a controllable range, a redox system in which a reducing agent is added may be employed.

Although the aforementioned adhesive composition is used to form the adhesive layer, when forming the adhesive layer, it is advisable to adjust the total amount of cross-linking agent added and fully consider the effects of cross-linking treatment temperature and cross-linking treatment time.

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

In addition, the cross-linking treatment may be a drying step of the adhesive layer It can be carried out at the same temperature, but it can also be carried out by providing a crosslinking treatment step separately after the drying step.

In addition, 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 with the adhesive layer of the present invention is only provided with a transparent protective film on one side of the polarizer, and no transparent protective film is provided on the other side, and an adhesive layer is formed on the polarizer using the above-mentioned adhesive composition.

The method of forming the adhesive layer can be prepared by, for example, the following method: apply the above-mentioned adhesive composition on the separation member subjected to the peeling treatment, then dry and remove the polymerization solvent, etc. to form an adhesive layer, and then transfer to the polarized light. The method on the film; or the method of coating the above-mentioned adhesive composition on the polarizing film, and then drying to remove the polymerization solvent, etc., to form an adhesive layer on the polarizing film, etc. In addition, one or more solvents other than the polymerization solvent may be appropriately added to the coating of the adhesive.

Polysiloxane release liners should be used for the separation parts that have been peeled off. In the step of coating and drying the adhesive composition of the present invention on such a backing material to form an adhesive layer, an appropriate and appropriate method may be adopted as a method of drying the adhesive depending on the purpose. It is desirable to employ a method of drying the above-mentioned coating film by heating. 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 within the above range, an adhesive having excellent adhesive properties can be obtained.

As the drying time, a suitable time can be appropriately adopted. above drying The time should be 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, especially 10 seconds to 5 minutes.

In addition, an anchor layer can be formed on the surface of the polarizing film, or an adhesive layer can be formed after various easy bonding treatments such as corona treatment and plasma treatment are applied. In addition, an easy-adhesion treatment may be performed on the surface of the adhesive layer.

Various methods can be used for the formation method of the adhesive layer. Specifically, for example, a roll coating method, a contact cot coating method, a gravure coating method, a reverse coating method, a roll brush method, a spray coating method, a dip roll coating method, a bar coating method, a blade coating method, and an air knife coating method are mentioned method, curtain coating method, lip coating method, extrusion coating method using a die coater, etc.

The thickness of the said adhesive bond layer is not specifically limited, For example, it is about 1-100 micrometers. It should be 2~50μm, more preferably 2~40μm, and more preferably 5~35μm.

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

In addition, the surface resistance value (A) of the adhesive layer before being stored in the humidified environment is preferably 1.0×10 ¹¹ Ω/□ or less, more preferably 8.0×10 ¹⁰ Ω/□ or less, and 5.0×10 ¹⁰ Ω/□ or less is particularly preferred.

When the aforementioned adhesive layer is exposed, a peel-treated sheet (separator) may also be used to protect the adhesive layer until practical use.

The constituent material of the separator includes, for example, polyethylene, polypropylene Plastic films such as vinyl, polyethylene terephthalate, polyester films, porous materials such as paper, cloth, and non-woven fabrics, meshes, foamed sheets, metal foils, and laminates, etc., as appropriate sheets etc., but since the surface smoothness is excellent, it is suitable to use a plastic film.

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

The thickness of the aforementioned separation member is usually 5 to 200 μm, preferably about 5 to 100 μm. The aforementioned separation parts can also be subjected to mold release and antifouling treatment using polysiloxane-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based mold release agents, silica powder, etc. Antistatic treatment such as kneading type and vapor deposition type. In particular, by appropriately performing peeling treatments such as polysiloxane treatment, long-chain alkyl treatment, and fluorine treatment on the surface of the separator, the peelability from the adhesive layer can be further improved.

In addition, the peeling-treated sheet used in the production of the above-mentioned polarizing film with an adhesive layer can be directly used as a separate part of the polarizing film with an adhesive layer, so that the manufacturing process can be simplified.

As the polarizing film, one having a transparent protective film on only one side of the polarizer can be used.

The polarizer is not particularly limited, and various polarizers can be used. Examples of polarizers include polyvinyl alcohol-based films and partially formalized polyvinyl alcohol. Hydrophilic polymer films such as ethylene-vinyl acetate copolymer films, partially saponified films, etc., adsorb iodine or dichroic substances of dichroic dyes and extend them uniaxially, as well as dehydrated products of polyvinyl alcohol or polychlorine Polyene-based alignment films such as ethylene dehydrochlorination products, etc. Among them, a polarizer composed of a polyvinyl alcohol-based film and a dichroic substance such as iodine is preferable. The thickness of these polarizers is not particularly limited, and is generally below about 80 μm.

A polarizer in which a polyvinyl alcohol-based film is dyed with iodine and uniaxially stretched can be produced by, for example, immersing a polyvinyl alcohol-based film in an aqueous solution of iodine to dye it, and extending it to 3 to 7 times its original length. become. It can also be immersed in an aqueous solution such as boric acid or potassium iodide which can contain zinc sulfate, zinc chloride, etc., as required. Further, the polyvinyl alcohol-based film may be immersed in water and washed with water before dyeing as necessary. By washing the polyvinyl alcohol-based film with water, dirt and anti-caking agents on the surface of the polyvinyl alcohol-based film can be washed off, and the polyvinyl alcohol-based film can be swelled to prevent uneven dyeing and other effects. The extension may be carried out after dyeing with iodine, or may be dyed and stretched at the same time, or may be dyed with iodine after extension. The extension can also be carried out 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 thinning and suppressing the occurrence of so-called penetration cracks. On the other hand, the thickness of the polarizer is 2 μm or more, more preferably 3 μm or more. The thin polarizer has less thickness variation, good visibility and less dimensional change, so it is excellent in durability against thermal shock.

Typical examples of thin polarizers include those described in Japanese Patent Publications. Japanese Patent Application Laid-Open No. 51-069644, Japanese Patent Application Laid-Open No. 2000-338329, Manual of WO2010/100917, PCT/JP2010/001460, Japanese Patent Application No. 2010-269002, or Japanese Patent Application The thin polarizing layer of Specification No. 2010-263692. These thin polarizing layers can be obtained by a production method comprising the following steps: a step 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 the state of a laminate; and staining step. With this production method, even if the PVA-based resin layer is thin, it can be stretched without problems such as fracture due to stretching by being supported by the stretching resin base material.

The above-mentioned thin polarizing layer, in the production method including the step of stretching in the state of the laminate and the step of dyeing, is preferably stretched at a high magnification to improve the polarizing performance. Manufactured from the publication manual, the specification of PCT/JP2010/001460, or the manufacturing method described in the specification of Japanese Patent Application No. 2010-269002 or the specification of Japanese Patent Application No. 2010-263692 including the step of extending in boric acid aqueous solution In particular, it is particularly desirable to use the method described in the specification of Japanese Patent Application No. 2010-269002 or the specification of Japanese Patent Application No. 2010-263692, which includes the step of performing auxiliary air stretching before stretching in an aqueous solution of boric acid. winner.

The thin high-function polarizing layer described in the specification of the above PCT/JP2010/001460 is integrally formed on a resin substrate, and is composed of a PVA-based resin in which dichroic substances are aligned, and has a thickness of 7 μm or less. The high-function polarizing layer has a single transmittance of 42.0% or more Optical properties with a degree of polarization above 99.95%.

The above-mentioned thin high-function polarizing layer can be produced as follows: by coating and drying a PVA-based resin, a PVA-based resin layer is formed on a resin substrate having a thickness of at least 20 μm, and the generated PVA-based resin layer is impregnated In the dyeing solution of the dichroic substance, the dichroic substance is adsorbed on the PVA-based resin layer, and the PVA-based resin layer and the resin substrate with the adsorbed dichroic substance are integrally stretched in the boric acid aqueous solution to a total extension ratio. become more than 5 times the original length.

In addition, the above-mentioned thin high-function polarizing layer can be produced by a method for producing a laminate film comprising a thin high-function polarizing layer in which a dichroic substance has been aligned, the method comprising the steps of: generating a laminate film, the The laminate film includes a resin substrate and a PVA-based resin layer with a thickness of at least 20 μm, and the PVA-based resin layer is formed on one side of the resin substrate by coating and drying an aqueous solution containing the PVA-based resin; In the adsorption step, the above-mentioned laminate film comprising a resin substrate and a PVA-based resin layer formed on one side of the resin substrate is immersed in a dyeing solution containing a dichroic substance, so that the laminate film contains The PVA-based resin layer adsorbs the dichroic substance; the extending step is performed in an aqueous solution of boric acid to extend the above-mentioned laminate film containing the PVA-based resin layer that has adsorbed the dichroic substance so that the total stretching ratio becomes more than 5 times the original length; and a step of manufacturing a laminated body film, which is formed with a thin high-function polarizing layer on one side of the resin base material by integrally extending the PVA-based resin layer that has adsorbed the dichroic substance and the resin base material, The thin high-performance polarizing layer is composed of a PVA-based resin layer in which dichroic substances have been aligned, and has a thickness of 7 μm Hereinafter, it has the optical properties of a single transmittance of 42.0% or more and a polarization degree of 99.95% or more.

The present invention is as described above, in the polarizing film of the above-mentioned adhesive layer, the following can be used as a polarizer with a thickness of 12 μm or less: a polarizing layer of a continuous base material composed of a PVA-based resin having oriented dichroic substances , and it is obtained by extending a laminate including a polyvinyl alcohol-based resin layer formed on a thermoplastic resin substrate by a 2-stage stretching step consisting of air-assisted stretching and boric acid water stretching. The aforementioned thermoplastic resin substrate is preferably an amorphous 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 Japanese Patent Application No. 2010-263692 is a polarizing layer of a continuous base material composed of a PVA-based resin having oriented dichroic substances, and it includes A laminate having a PVA-based resin layer formed on an amorphous ester-based thermoplastic resin substrate is stretched to a thickness of 12 μm or less by two-stage stretching steps consisting of air-assisted stretching and boric acid water stretching. When the transmittance of the monomer is T and the degree of polarization is P, the thin polarizing layer should be made to satisfy P>-(10 ^{0.929T-42.4-1} )×100 (only T<42.3), and P≧99.9 (only T≧42.3) conditions of optical properties.

Specifically, the above-mentioned thin polarizing layer can be manufactured by a manufacturing method of a thin polarizing layer comprising the following steps: the step of generating an extended intermediate product is to form a film on an amorphous ester-based thermoplastic resin substrate of a continuous base material The PVA-based resin layer is stretched at high temperature in the air, thereby generating an extended intermediate product composed of the aligned PVA-based resin layer; The product step is to make the extension intermediate product adsorb dichroic substances, thereby generating a colored intermediate product composed of a PVA-based resin layer that has oriented dichroic substances (preferably iodine or a mixture of iodine and organic dyes); And the step of generating a polarizing layer is to extend the colored intermediate product in boric acid water, thereby generating a polarizing layer with a thickness of 12 μm or less, which is composed of a PVA-based resin layer in which dichroic substances have been aligned.

In this manufacturing method, the total stretching ratio of the PVA-based resin layer formed on the amorphous ester-based thermoplastic resin substrate by high-temperature stretching in the air and stretching in boric acid water is preferably 5 times or more. The liquid temperature of the boric acid aqueous solution used for the boric acid water extension can be set to 60°C or higher. Before extending the colored intermediate product in the boric acid aqueous solution, the colored intermediate product is preferably subjected to insolubilization treatment, and at this time, the colored intermediate product is preferably immersed in the boric acid aqueous solution whose liquid temperature does not exceed 40°C. The above-mentioned amorphous ester-based thermoplastic resin base material can be made of a polyethylene terephthalate copolymer obtained by copolymerizing isophthalic acid and a polyethylene terephthalate copolymer obtained by copolymerizing cyclohexanedimethanol Amorphous polyethylene terephthalate copolymer of diester copolymer or other copolymerized polyethylene terephthalate, preferably composed of transparent resin, and its thickness can be set as a film-forming PVA system More than 7 times the thickness of the resin layer. In addition, the stretching ratio of high temperature stretching in air is preferably 3.5 times or less, and the stretching temperature of high temperature stretching in air is preferably higher than the glass transition temperature of the PVA resin, specifically in the range of 95°C to 150°C. When performing high-temperature in-air stretching by free-end uniaxial stretching, 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 addition, when in-air high-temperature stretching is performed by uniaxial stretching at the fixed end, a film is formed on the amorphous The total stretching ratio of the PVA-based resin layer of the 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.

The base material of the continuous base material of isophthalic acid copolyethylene terephthalate (amorphous PET) copolymerized with isophthalic acid 6 mol% is produced. The glass transition temperature of amorphous PET was 75°C. A laminate composed of an amorphous PET substrate of a continuous base and a polyvinyl alcohol (PVA) layer was produced as follows. Incidentally, the glass transition temperature of PVA is 80°C.

Prepare an amorphous PET base material with a thickness of 200 μm and a PVA aqueous solution with a concentration of 4~5%, which is prepared by dissolving PVA powder with a degree of polymerization of 1000 or more and a degree of saponification of 99% or more in water. Next, the PVA aqueous solution was coated on the amorphous PET substrate with a thickness of 200 μm, and dried at a temperature of 50 to 60° C. to obtain a laminate with a 7 μm thick PVA layer formed on the amorphous PET substrate. .

The laminate including a 7-μm-thick PVA layer was subjected to the following steps including two-stage extension steps including aerial-assisted extension and boric acid water extension to produce a 3-μm-thick thin high-function polarizing layer. In the air-assisted stretching step in the first stage, the laminate including the 7 μm thick PVA layer and the amorphous PET substrate were integrally stretched to produce a 5 μm thick PVA layer stretched laminate. Specifically, the stretched laminated body is a stretching device equipped with a laminated body including a 7 μm thick PVA layer placed in an oven, and uniaxially stretched through the free end to a stretch ratio of 1.8 times, and the oven is set to 130 ℃ extension temperature environment. By this extending process, the PVA layer included in the extended laminate is converted into a 5 μm thick PVA layer in which PVA molecules are aligned.

Then, using the dyeing step, iodine is adsorbed on the 5-μm-thick PVA layer in which the PVA molecules are aligned to form a colored laminate. Specifically, the colored laminate is obtained by immersing the stretched laminate in a dyeing solution containing iodine and potassium iodide at a liquid temperature of 30° C. for an arbitrary period of time, so that the PVA constituting the final high-function polarizing layer is formed. The individual transmittance of the layer is 40 to 44%, whereby iodine is adsorbed on the PVA layer contained in the stretched laminate. In this step, the dyeing solution uses water as a solvent, and the concentration of iodine is set within the range of 0.12-0.30 wt % and the concentration of potassium iodide is within the range of 0.7-2.1 wt %. The concentration ratio of iodine to potassium iodide is 1 to 7. Incidentally, potassium iodide is necessary to dissolve iodine in water. More specifically, by immersing the stretched laminate in a dyeing solution with an iodine concentration of 0.30 wt % and a potassium iodide concentration of 2.1 wt % for 60 seconds, a colored laminate in which iodine is absorbed by PVA molecules through an aligned 5 μm-thick PVA layer is produced. body.

In the second step of extending in boric acid water, the colored laminate and the amorphous PET substrate were further extended integrally to produce an optical film laminate including a 3 μm-thick PVA layer for constituting a high-performance polarizing layer. Specifically, the optical film laminate is an extension device equipped with the colored laminate placed in a processing device, and uniaxially extended through the free end to a stretching ratio of 3.3 times, and the processing device is set to contain boric acid and Potassium iodide is a boric acid aqueous solution with a liquid temperature ranging from 60 to 85 °C. More specifically, the liquid temperature of the boric acid aqueous solution was 65°C. Moreover, the content of boric acid is 4 parts by weight with respect to 100 parts by weight of water, and the content of potassium iodide is 5 parts by weight with respect to 100 parts by weight of water. In this step, the colored layered body whose iodine adsorption amount has been adjusted is first immersed in a boric acid aqueous solution for 5 to 10 seconds. Then, make the coloring layer The body directly passes through the multiple sets of rollers with different rotational speeds of the extension device equipped in the processing device, and the free end is uniaxially extended for 30 to 90 seconds to achieve an extension ratio of 3.3 times. By this stretching treatment, the PVA layer contained in the colored laminate 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 complex of polyiodide ions. The PVA layer can constitute the high-function polarizing layer of the optical film laminate.

Although it is not an essential step in the production of optical film laminates, it is preferable to wash the optical film laminates with an aqueous potassium iodide solution in a washing step, and take out the optical film laminates from the boric acid aqueous 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 cleaned optical film laminate was dried by a drying step using warm air at 60°C. In addition, the cleaning step is a step for solving appearance defects such as boric acid precipitation.

Similarly, although it is not a necessary step in the production of optical film laminates, it is also possible to apply the adhesive to the 3 μm thick film formed on the amorphous PET substrate through the lamination and/or transfer steps. On the surface of the PVA layer, a (meth)acrylic resin film containing a lactone ring structure with a thickness of 40 μm was pasted, and then the amorphous PET substrate was peeled off to transfer the PVA layer with a thickness of 3 μm to a thickness of 40 μm containing lactone. On the (meth)acrylic resin film of the ring structure.

[Other steps]

In addition to the above-mentioned steps, the above-mentioned manufacturing method of 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. The other steps can be performed at any and appropriate time points.

The above-mentioned insolubilization step is typically performed by immersing the PVA-based resin layer in a boric acid aqueous solution. Water resistance can be imparted to the PVA-based resin layer by performing the insolubilization treatment. With respect to 100 parts by weight of water, the concentration of the boric acid aqueous solution is preferably 1 part by weight to 4 parts by weight. The temperature of the insoluble bath (boric acid aqueous solution) is preferably 20°C to 50°C. The insolubilization step is preferably performed after the layered body is produced, and before the dyeing step or the water elongation step.

The aforementioned crosslinking step is typically performed by immersing the PVA-based resin layer in a boric acid aqueous solution. By performing the crosslinking treatment, water resistance can be imparted to the PVA-based resin layer. With respect to 100 parts by weight of water, the concentration of the boric acid aqueous solution is preferably 1 part by weight to 4 parts by weight. In addition, when the cross-linking step is performed after the above-mentioned dyeing step, it is more preferable to blend iodide. By blending the iodide, the elution of the iodine adsorbed on the PVA-based resin layer can be suppressed. And relative to 100 parts by weight of water, the blending amount of iodide is preferably 1 part by weight to 5 parts by weight. Specific examples of the iodide are as described above. The liquid temperature of the cross-linking bath (boric acid aqueous solution) is preferably 20°C to 50°C. The cross-linking step is preferably performed before the above-mentioned second extension step in boric acid water. In a preferred embodiment, the dyeing step, the cross-linking step and the second extension step in boric acid water are performed in sequence.

As the material constituting the transparent protective film, for example, thermoplastic resins excellent in transparency, mechanical strength, thermal stability, moisture resistance, and isotropy can be used. Specific examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose, polyester resins, polyether resins, polysiloxane resins, polycarbonate resins, polyamide resins, and polyimide resins. , polyolefin resins, (meth)acrylic resins, cyclic polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins and the like mixture. One or more optional and appropriate additives may be contained in the transparent protective film. Examples of additives include ultraviolet absorbers, antioxidants, slip agents, plasticizers, mold release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, colorants, and the like. In the transparent protective film, the content of the thermoplastic resin is preferably 50-100% by weight, preferably 50-99% by weight, more preferably 60-98% by weight, and particularly preferably 70-97% 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 fully exhibit the high transparency that it originally has.

In addition, the transparent protective film is bonded to one side of the polarizer through the adhesive layer. An adhesive can be used for the adhesive treatment of the polarizer and the transparent protective film. As an adhesive agent, an isocyanate type adhesive agent, a polyvinyl alcohol type adhesive agent, a gelatin type adhesive agent, a vinyl type latex type, a water type polyester etc. can be illustrated, for example. The aforementioned adhesive is usually used as an adhesive composed of an aqueous solution, and usually contains 0.5 to 60% by weight of solid content. In addition to the above, as the adhesive for the polarizer and the transparent protective film, for example, an ultraviolet curable adhesive, an electron beam curable adhesive, and the like can be exemplified. The adhesive for electron beam curable polarizing films can exhibit suitable adhesiveness to the above-mentioned various transparent protective films. In addition, the adhesive used in the present invention may contain a metal compound filler.

Furthermore, the aforementioned polarizing film can be laminated with other optical films. Other optical films include, for example, reflective plates or anti-transmission plates, retardation films (including 1/2 or 1/4 wavelength plates), viewing angle compensation films, brightness enhancement films, etc., which can also be used to form optical layers of liquid crystal display devices, etc. By. These can be layered on the aforementioned polarizing film using one layer or two or more layers in practical application.

Optical thin film having the aforementioned optical layer laminated on a polarizing film Although the film can be formed by lamination in sequence in the manufacturing process of liquid crystal display devices, etc., the pre-laminated optical films have excellent quality stability and assembly operations, etc., and have the advantages of improving liquid crystal display devices, etc. Advantages of manufacturing steps. Appropriate bonding means such as an adhesive layer can be used for lamination. When the above-mentioned polarizing film is bonded to other optical layers, the optical axes can be set to an appropriate arrangement angle according to the desired retardation characteristics and the like.

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

The polarizing film with the 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 proceed as usual. That is, a liquid crystal display device is generally formed by appropriately assembling a display panel such as a liquid crystal cell, a polarizing film adhering to an adhesive layer, and components such as a lighting system as required, and incorporating a driving circuit, etc. There is no particular limitation except that the pressure-sensitive adhesive layer optical film of the present invention is used, and conventional knowledge can be followed. For the liquid crystal cell, for example, any type of liquid crystal cell such as TN type, STN type, π type, VA type, and IPS type can be used.

An appropriate liquid crystal display device such as a liquid crystal display device in which a polarizing film with an adhesive layer is arranged on one or both sides of a display panel such as a liquid crystal cell, or a backlight or a reflector for the lighting system can be formed. At this time, the polarizing film with the adhesive layer of the present invention can be arranged on one side or both sides of a display panel such as a liquid crystal cell. And set the optical film on both sides , these may be the same or different. In addition, when forming a liquid crystal display device, one or more layers such as a diffusion layer, an anti-glare layer, an anti-reflection film, a protective plate, a mirror array, a lens array sheet, a light-diffusing sheet, a backlight can be arranged at appropriate positions. appropriate parts, etc.

Example

Hereinafter, the present invention will be specifically described with examples, but the present invention is not limited by these examples. As for the parts and % in each example, they are all based on weight. Below, the room temperature storage conditions that are not specified are all 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).

‧Analysis device: HLC-8120GPC manufactured by Tosoh Corporation

‧Column: Tosoh Corporation, G7000H _XL +GMH _XL +GMH _XL

‧Column size: 7.8mm φ×30cm each, 90cm in total

‧Column temperature: 40℃

‧Flow: 0.8ml/min

‧Injection volume: 100μl

‧Eluent: Tetrahydrofuran

‧Detector: Differential Refractometer (RI)

‧Standard sample: polystyrene

<Production of polarizing film>

(Production of polarizer)

Corona treatment was applied to one side of the substrate of amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 μm) with a water absorption rate of 0.75% and a Tg of 75 °C, and the The halo-treated surface was coated at 25°C with polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetylacetate modified PVA (polymerization degree 1200, acetylacetate) in a ratio of 9:1. The degree of radical modification was 4.6%, the degree of saponification was 99.0 mol% or more, and an aqueous solution of Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gohsefimer Z200") was dried to form a PVA-based resin layer with a thickness of 11 μm, and a laminate was produced.

The obtained layered body was uniaxially stretched 2.0 times at the free end in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds in an oven at 120° C. (aerial-assisted stretching treatment).

Next, the layered body was immersed in an insolubilization bath (a boric acid aqueous solution obtained by blending 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 (insolubility treatment).

Next, it was immersed in a dyeing bath with a liquid temperature of 30° C. while adjusting the iodine concentration and the immersion time so that the polarizing plate had a predetermined transmittance. In this example, it was immersed for 60 seconds in an iodine aqueous solution obtained by blending 0.2 parts by weight of iodine and 1.0 parts by weight of potassium iodide with respect to 100 parts by weight of water (dyeing treatment).

Next, it was immersed in a crosslinking bath (a boric acid aqueous solution obtained by mixing 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with respect to 100 parts by weight of water) for 30 seconds in a crosslinking bath (crosslinking treatment) at a liquid temperature of 30°C. .

Then, the layered body was immersed in an aqueous solution of boric acid (an aqueous solution obtained by blending 4 parts by weight of boric acid and 5 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 70° C. while the peripheral speed was different. longitudinally between the rollers The direction (long-side direction) was uniaxially stretched to a total stretching ratio of 5.5 times (underwater stretching treatment).

Then, the layered body was immersed in a cleaning bath (aqueous solution obtained by mixing 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 30°C (cleaning treatment).

Through the above steps, an optical film laminate including a polarizer with a thickness of 5 μm and a boric acid content of 16% was obtained.

<Production of adhesive for transparent protective film>

40 parts by weight of N-hydroxyethyl acrylamide (HEAA), 60 parts by weight of acryl molyfrine (ACMO), and 3 parts by weight of photoinitiator "IRGACURE 819" (manufactured by BASF) were blended to prepare ultraviolet rays Hardening adhesive.

(Production of polarizing film)

While applying the above-mentioned ultraviolet curable adhesive on the surface of the polarizer of the optical film laminate, corona treatment was applied to the easily bondable surface of the (meth)acrylic resin film containing a lactone ring structure with a thickness of 40 μm, and the film was bonded together. After that, the amorphous PET base material 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 introduction tube, and a cooler, feed containing 80.3 parts of butyl acrylate, 0.5 part of 4-hydroxybutyl acrylate, 0.2 part of acrylic acid, and 3 N-vinylpyrrolidone. parts and 16 parts of phenoxyethyl acrylate monomer mixture. Next, 0.15 part of 2,2′-azobisisobutyronitrile as a polymerization initiator was fed with ethyl acetate with respect to 100 parts of the aforementioned monomer mixture (solid content), and nitrogen was introduced while stirring slowly. After the gas was replaced with nitrogen, the liquid temperature in the flask was maintained at around 60°C, and a polymerization reaction was performed for 7 hours. Then, ethyl acetate was added to the obtained reaction liquid, and the solution of the acrylic polymer (A1) whose solid content concentration was adjusted to 30% and a weight average molecular weight of 1,400,000 was prepared.

<Preparation of acrylic polymers (A2) to (A12)>

The solutions of acrylic polymers (A2) to (A12) were prepared in the same manner except that the monomer composition was changed as shown in Table 1 and the polymerization conditions were adjusted in the preparation of the above-mentioned acrylic polymer (A1). .

Example 1

(preparation of adhesive composition)

With respect to 100 parts of solid content of the obtained acrylic polymer (A1) solution, 1 part of lithium bis(trifluoromethanesulfonyl)imide (manufactured by Mitsubishi Material Electrochemical Co., Ltd.) was blended, and trimethylolpropane was blended Hexamethylene diisocyanate (manufactured by Mitsui Chemicals, trade name "Takenate D-160N") 0.17 parts, dibenzoyl peroxide 0.25 parts, silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "X- 41-1810") 0.2 parts by weight and 0.2 parts by weight of an acetylacetyl group-containing silane coupling agent (manufactured by Soken Chemical Co., Ltd., trade name "A-100") to prepare an acrylic adhesive solution.

(Production of polarizing film with adhesive layer)

Next, on the surface of the polyethylene terephthalate film (separation film) treated with the polysiloxane-based release agent, the above-mentioned acrylic adhesive solution was uniformly coated with a spray coater, and the solution was applied at 155 After drying in an air circulation type constant temperature oven at ℃ for 1 minute, an adhesive layer with a thickness of 20 μm was formed on the surface of the separation film. Next, transfer the adhesive layer formed on the separation film To the side of the polarizing layer of the polarizer of the thin polarizing film made above, a polarizing film with an adhesive layer is produced.

Embodiment 2~9, comparative example 1~4

A polarizing film with an adhesive layer was produced in the same manner as in Example 1, except that the types and usage amounts of each component were changed as shown in Table 1 when preparing the adhesive composition in Example 1.

The following evaluations were performed with respect to the polarizing films with the adhesive layers obtained in the above examples and comparative examples. The evaluation results are listed in Table 1.

<Measurement of the amount of change in the degree of polarization>

The separation film of the polarizing film with the adhesive layer was peeled off, and attached to a microscope slide (manufactured by Matsunami Glass Ind., Ltd., trade name "S200") using a laminator. Next, autoclave treatment was performed at 50° C. and 0.5 MPa for 15 minutes, so that the polarizing film with the adhesive layer was completely adhered to the acrylic-free glass. Next, it stored in the humidified environment of 60 degreeC/90%RH for 500 hours. The degree of polarization of the polarizing film before and after storage was measured using V7100 manufactured by Nippon Co., Ltd. The amount of change in the degree of polarization was calculated by the following formula and evaluated according to the following criteria.

Variation △P=(Polarization degree before storage)-(Polarization degree after storage)

(assessment benchmark)

◎: 0≦△P<0.02

○: 0.02≦△P<0.04

△: 0.04≦△P<0.05

×: 0.05≦△P

<Measurement of Surface Resistance Change Rate>

After peeling off the separation film of the polarizing film adhering to the adhesive layer, the surface resistance value (Ω/□) of the adhesive surface was measured using MCP-HT450 manufactured by Mitsubishi Chemical Analytech. Moreover, after storing the polarizing film with the adhesive layer in a humidified environment of 60° C./90% RH for 500 hours, the surface resistance value of the adhesive surface was also measured in the same manner as described above. The change rate (%) of the surface resistance value was calculated by the following formula, and evaluated according to the following criteria.

Change rate △R(%)=(surface resistance value after storage)×100/(surface resistance value before storage)

(assessment benchmark)

◎: 0≦△R<300

○: 300≦△R<500

△: 500≦△R<700

×: 700≦△R

<Measurement of haze>

After peeling off the separation film of the polarizing film with the adhesive layer, according to the method established in JIS 7136, use a haze meter (manufactured by Murakami Color Science Institute, HN-150) to measure the haze of the polarizing film with the adhesive layer. (%). The haze of the polarizing film attached to the adhesive layer is preferably below 3%, more preferably below 1%.

The compounds in Table 1 are as follows.

BA: Butyl Acrylate

4HBA: 4-hydroxybutyl acrylate

AA: Acrylic

NVP: N-Vinylpyrrolidone

ACMO: N-acryloyl molyfrin

MMA: methyl methacrylate

PEA: phenoxyethyl acrylate

LiTFSi: Lithium bis(trifluoromethanesulfonyl)imide (manufactured by Mitsubishi Material Electronics Co., Ltd.)

EMPTFSi: ethylmethylpyrrolidinium-bis(trifluoromethanesulfonyl)imide (manufactured by Tokyo Chemical Industry Co., Ltd.)

industrial availability

The polarizing film with the adhesive layer of the present invention can be used alone or as an optical film formed by laminating it in image display devices such as liquid crystal display devices (LCD) and organic EL display devices.

Claims (9)

A polarizing film with an adhesive layer, comprising a polarizing film and an adhesive layer arranged on the polarizing film, the polarizing film with the adhesive layer is characterized in that: the polarizing film only has a transparent protective film on one side of the polarizer, The above-mentioned adhesive layer is provided on the side of the polarizer without the above-mentioned transparent protective film; and the above-mentioned adhesive layer is formed by an adhesive composition containing a (meth)acrylic polymer and an alkali metal salt; the above-mentioned ( The meth)acrylic polymer contains a monomer (1) having a nitrogen atom and a carbon-carbon double bond as a monomer unit; the aforementioned monomer (1) is a lactamide-based monomer; the alkali metal in the aforementioned alkali metal salt The bonding energy with iodide anion (I ^- ) is above 50kcal/mol. The polarizing film with an adhesive layer according to claim 1 or 2, wherein the alkali metal in the alkali metal salt is lithium. The polarizing film with an adhesive layer according to claim 1 or 2, 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 claim 1 or 2, wherein the adhesive composition contains 0.01 to 5 parts by weight of an alkali metal salt relative to 100 parts by weight of the (meth)acrylic polymer. The polarizing film with an adhesive layer as claimed in claim 1 or 2, wherein the difference between the surface resistance value (B) and the surface resistance value (A) of the above-mentioned adhesive layer The rate of change (B×100/A) is 700% or less, the surface resistance value (B) is the resistance value after being stored in a humidified environment of 60°C/90%RH for 500 hours, and the surface resistance value (A) is the The resistance value before storage in the aforementioned humidified environment. The polarizing film with an adhesive layer according to claim 5, wherein the surface resistance value (A) of the adhesive layer before being stored in the humidified environment is 1.0×10 ¹¹ Ω/□ or less. The polarizing film with an adhesive layer according to claim 1 or 2, wherein the thickness of the polarizer is below 12 μm. The polarizing film with an adhesive layer as claimed in claim 1 or 2, wherein the polarization degree (B) and the change (A-B) of the polarization degree (A) of the polarizing film with an adhesive layer are within 0.05, and the polarization degree ( B) is the degree of polarization after storage in a humidified environment of 60°C/90%RH for 500 hours, and this degree of polarization (A) is the degree of polarization before storage in the humidified environment. An image display device, characterized by using at least one polarizing film with an adhesive layer according to any one of claims 1 to 8.