TW201930932A - Polarizing plate with adhesive layer - Google Patents

Abstract

The present invention provides a polarizing plate with an adhesive layer, which is thin and has extremely excellent moisture resistance. A polarizing plate with an adhesive layer according to the present invention comprises: a polarizer; a protective film which is arranged on one surface of the polarizer; and an adhesive layer which is arranged on the other surface of the polarizer. The polarizer has an iodine content of from 10% by weight to 25% by weight; the adhesive layer contains a conductive agent; and the conductive agent contains an inorganic cation salt.

Description

Polarizer with adhesive layer

The present invention relates to a polarizing plate with an adhesive layer.

BACKGROUND OF THE INVENTION In a liquid crystal display device which is a typical image display device, a polarizing member (a substantially polarizing plate including a polarizing member) is disposed on both sides of a liquid crystal cell due to an image forming method. The polarizer is produced by dyeing a polyvinyl alcohol (PVA) resin film with a dichroic substance such as iodine. In recent years, the demand for thinning of image display devices has increased. Therefore, the polarizing member is also required to be further thinned. However, the thinner the polarizer, the more the moisture resistance is easily reduced in high temperature and high humidity environments.

CITATION LIST Patent Literature Patent Literature 1: Japanese Laid-Open Patent Publication No. JP-A No. Hei. No. Hei. Bulletin 094907

DISCLOSURE OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION The present invention has been made to solve the above problems, and a main object thereof is to provide a polarizing plate having an adhesive layer having a thin and excellent moisture resistance.

Means for Solving the Problem A polarizing plate with an adhesive layer of the present invention has a polarizing member, a protective film disposed on one side of the polarizing member, and an adhesive layer disposed on the other side of the polarizing member. The polarizer has an iodine content of 10% by weight to 25% by weight, the adhesive layer contains a conductive agent, and the conductive agent contains an inorganic cation salt.
In one embodiment, the inorganic cation salt is a lithium salt.
In one embodiment, the anion of the anion portion constituting the inorganic cation salt is selected from the group consisting of the anions represented by the following general formulae (1) to (4):
(1): (C _n F _2n+1 SO ₂ ) ₂ N ^- (n is an integer from 1 to 10),
(2): CF ₂ (C _m F _2m SO ₂ ) ₂ N ^- (m is an integer from 1 to 10),
(3): ^- O ₃ S(CF ₂ ) _l SO ₃ ^- (l is an integer from 1 to 10),
(4): (C _p F _2p+1 SO ₂ )N ^- (C _q F _2q+1 SO ₂ ), (p, q is an integer of 1 to 10).
In one embodiment, the content of the inorganic cation salt is from 0.01 part by weight to 5 parts by weight based on 100 parts by weight of the base polymer of the pressure-sensitive adhesive layer.
In one embodiment, the conductive agent further comprises an organic cation salt.
In one embodiment, the content of the organic cation salt is from 0.1 part by weight to 10 parts by weight based on 100 parts by weight of the base polymer of the pressure-sensitive adhesive layer.
In one embodiment, the polarizer has a thickness of 3 μm or less.

Advantageous Effects of Invention According to the present invention, by introducing a conductive agent containing an inorganic cation salt (preferably a lithium salt) into the adhesive layer, even if a thin polarizing member having a very large iodine content is used, extremely excellent moisture resistance can be achieved.

MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below, but the present invention is not limited by the embodiments.

A. Outline of Polarizing Plate with Adhesive Layer FIG. 1 is a schematic cross-sectional view of a polarizing plate with an adhesive layer according to an embodiment of the present invention. The polarizing plate 100 with an adhesive layer as shown in the drawings has a polarizing element 10, a protective film 20 disposed on one side of the polarizing member 10, and an adhesive layer 30 disposed on the other side of the polarizing member. The adhesive layer 30 is the outermost layer on the side of the image display device. In an embodiment of the present invention, the polarizing member has an iodine content of 10% by weight to 25% by weight. Also, the adhesive layer contains a conductive agent, and the conductive agent contains an inorganic cation salt.

In actual use, on the adhesive layer 30, the separator (not shown) is temporarily adhered in a peelable state, and the adhesive layer can be protected until it is actually used, and can be formed into a roll shape. Another protective film (not shown) may be disposed between the polarizer 10 and the adhesive layer 30 as needed. A retardation film (not shown) may be disposed between the polarizer 10 and the adhesive layer 30 or outside the protective film 20 as needed. The optical characteristics of the retardation film (for example, the refractive index ellipsoid, the in-plane phase difference, the thickness direction phase difference, the Nz coefficient, and the wavelength dispersion characteristic), the number of arranged sheets, the combination, the slow axis, and the angle of the absorption axis of the polarizing member, etc. Make appropriate settings according to the purpose.

Hereinafter, the polarizer, the protective film, and the adhesive layer constituting the polarizing plate with the adhesive layer will be specifically described.

B. Polarizer
B-1. Configuration and Characteristics of Polarizer The polarizer is preferably composed of a polyvinyl alcohol (PVA) resin film. The PVA-based resin forming the PVA-based resin film may, for example, be a polyvinyl alcohol or an ethylene-vinyl alcohol copolymer. Polyvinyl alcohol can be obtained by saponifying polyvinyl acetate. The ethylene-vinyl alcohol copolymer can be obtained by saponifying an ethylene-vinyl acetate copolymer. The saponification degree of the PVA-based resin is usually 85 mol% or more and less than 100 mol%, preferably 95.0 mol% to 99.95 mol%, more preferably 99.0 mol% to 99.93 mol%. The degree of saponification can be determined in accordance with JIS K 6726-1994. By using the PVA-based resin having a saponification degree, a polarizing member excellent in durability can be obtained. When the degree of saponification is too high, there will be a gelatinization.

The average degree of polymerization of the PVA-based resin can be appropriately selected depending on the purpose. The average degree of polymerization is usually from 1000 to 10,000, preferably from 1200 to 4500, and more preferably from 1,500 to 4,300. Further, the average degree of polymerization can be obtained in accordance with JIS K 6726-1994.

In one embodiment, the PVA-based resin film may be a PVA-based resin layer formed on a substrate. The laminate of the substrate and the PVA-based resin layer can be obtained by a method of applying a coating liquid containing the PVA-based resin to a substrate, and laminating a PVA-based resin film to a substrate. Method, etc.

The iodine content of the polarizer can be suitably set to have both sufficient polarizing performance and optimum monomer transmittance. The iodine content is from 10% by weight to 25% by weight, and preferably from 15% by weight to 25% by weight, as described above. According to the embodiment of the present invention, by using a specific adhesive layer to be described later in the polarizing plate including the polarizer having an extremely high iodine content, it is possible to achieve extremely excellent moisture resistance which has been difficult to achieve in the past. More specifically, in the polarizing plate containing the polarizer having an extremely high iodine content, the change in the transmittance of the single body, the change in the degree of polarization, and the change in the hue in a high-temperature and high-humidity environment can be remarkably suppressed. The "iodine content" in the present specification means the amount of all iodine contained in the polarizing member (PVA-based resin film). More specifically, iodine exists in the polarizing member in the form of iodide ion (I ^- ), iodine molecule (I ₂ ), polyiodide ion (I ₃ ^- , I ₅ ^- ), and the iodine content in the present specification means Contains the amount of all of these forms of iodine. The iodine content can be calculated by a calibration curve method such as fluorescent X-ray analysis. Further, polyiodide ions are present in the polarizer in a state in which a PVA-iodine complex is formed. By forming the complex, absorption dichroism can be exhibited in the wavelength range of visible light. Specifically, a complex of PVA and triiodide ions (PVA·I ₃ ^- ) has an absorption peak near 470 nm; a complex of PVA and penta-iodide ions (PVA·I ₅ ^- ) has absorption at around 600 nm. peak. As a result, polyiodide ions can absorb light in a wide range of visible light depending on their morphology. On the other hand, the iodide ion (I ^- ) has an absorption peak near 230 nm, which has no substantial correlation with the absorption of visible light. Therefore, the polyiodide ion existing in the form of a complex with PVA is mainly related to the absorption performance of the polarizer.

The upper limit of the thickness of the polarizer is 5 μm in one embodiment, 3 μm in another embodiment, and 2 μm in another embodiment. The lower limit of thickness is 0.5 μm in one embodiment, 0.6 μm in another embodiment, and 0.8 μm in another embodiment, and 1 μm in another embodiment. In another embodiment, 2 μm. According to the embodiment of the present invention, even if the polarizer is thin, the desired single transmittance and degree of polarization can be achieved.

The single transmittance (Ts) of the polarizer is preferably from 30.0% to 43.0%, preferably from 35.0% to 41.0%. The polarizing degree of the polarizing member is preferably 99.9% or more, more preferably 99.95% or more, and still more preferably 99.98% or more. By setting the single transmittance to be lower and setting the degree of polarization higher, the contrast can be improved and the black display can be made darker, so that an image display device having excellent image quality can be realized. In addition, the monomer transmittance is a value measured by a spectrophotometer with an integrating sphere. The monomer transmittance is measured by the 2D field of view (C light source) of JIS Z8701 and the Y value obtained by correcting the optical performance. For example, an ultraviolet-visible spectrophotometer with an integrating sphere (manufactured by JASCO Corporation) can be used. Product name: V7100) was measured.

In the embodiment of the present invention, even if the iodine content of the polarizing member is extremely high, the change in optical characteristics in a high-temperature and high-humidity environment as described later in the examples is remarkably suppressed. Moreover, the hue change in high temperature and high humidity environments is also suppressed. The excellent effect can be achieved by using an adhesive layer into which a conductive agent containing an inorganic cation salt as described above is introduced, in combination with a polarizing member as described above. In more detail, we presume that the iodine complex is stabilized by the inorganic cation (for example, lithium ion) from the conductive agent in the adhesive layer and the iodine complex in the polarizer, and as a result, iodine can be suppressed (especially It is such that I ₃ ^- and I ₅ ^- polyiodide ions are reduced in a high temperature and high humidity environment, thereby achieving the excellent effect. This solves the problem newly discovered by actually making a very thin (for example, a thickness of 3 μm or less) polarizing material which has been difficult to manufacture in the past, and is an unexpectedly excellent effect.

B-2. Method of manufacturing polarizer
B-2-1. Outline of Manufacturing Method A polarizing material can be produced by a production method including at least stretching and dyeing a PVA-based resin film. Representatively, the manufacturing method includes a step of preparing a PVA-based resin film, an extending step, a swelling step, a dyeing step, a crosslinking step, a washing step, and a drying step. Each step of supplying a PVA-based resin film can be carried out in an arbitrary and appropriate order and timing. Therefore, the steps may be performed in the above order, or may be performed in a different order than the above. One step can be performed multiple times depending on the needs. In addition, steps other than the above (such as insoluble steps) can be performed at any and appropriate timing. Further, in the case of a PVA-based resin layer in which a PVA-based resin film is formed on a substrate, a laminate of a substrate and a PVA-based resin layer can be supplied to the above step.

Each step will be described below, but as described above, each step can be performed in an arbitrary and appropriate order, and is not limited by the order of description.

B-2-2. Extension Step In the stretching step, the PVA-based resin film represents that the upper system is uniaxially stretched by 3 times to 7 times. The extending direction may be the longitudinal direction of the film (MD direction) or the width direction of the film (TD direction). The stretching method may be a dry stretching, a wet stretching, or may be combined. Further, the PVA-based resin film may be stretched when the crosslinking step, the swelling step, the dyeing step, or the like is performed. Further, the extending direction may correspond to the absorption axis direction of the obtained polarizer.

B-2-3. Swelling Step The swelling step is usually carried out before the dyeing step. The swelling step can be carried out, for example, by immersing the PVA-based resin film in a swelling bath. The swelling bath is usually water such as distilled water or pure water. The swelling bath may also contain any suitable and other ingredients other than water. Examples of other components include solvents such as alcohols, additives such as surfactants, and iodides. Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, cesium iodide, calcium iodide, tin iodide, and titanium iodide. Potassium iodide should be used. The temperature of the swelling bath is, for example, 20 ° C to 45 ° C. Further, the immersion time is, for example, 10 seconds to 300 seconds.

B-2-4. Dyeing Step The dyeing step is a step of dyeing a PVA-based resin film with a dichroic substance. It is preferred to carry out the adsorption of the dichroic substance. The adsorption method may be a method of immersing a PVA-based resin film in a dyeing liquid containing a dichroic substance, a method of applying the dyeing liquid to a PVA-based resin film, and spraying the dyeing liquid to a PVA system. A method of a resin film or the like. A method of immersing the PVA-based resin film in the dyeing liquid is preferred. Because the dichroic substance can be well adsorbed.

The above dichroic substance may, for example, be iodine or a dichroic dye. And iodine is preferred. When iodine is used as the dichroic substance, the aqueous solution of iodine is preferably used as the dyeing solution. The iodine content of the aqueous iodine solution is preferably from 0.04 parts by weight to 5.0 parts by weight based on 100 parts by weight of the water. In order to increase the solubility of iodine in water, it is preferred to incorporate iodide in an aqueous solution of iodine. Potassium iodide is preferred for the iodide. The iodide content is preferably from 0.3 part by weight to 15 parts by weight per 100 parts by weight of the water.

The liquid temperature at the time of dyeing of the dyeing liquid can be set to an arbitrary and appropriate value, for example, 20 ° C to 50 ° C. When the PVA-based resin film is immersed in the dyeing liquid, the immersion time is, for example, 5 seconds to 5 minutes.

B-2-5. Crosslinking Step In the crosslinking step, a boron compound is usually used as a crosslinking agent. The boron compound may, for example, be boric acid or borax. And boric acid is preferred. In the crosslinking step, the boron compound is usually used in the form of an aqueous solution.

When a boric acid aqueous solution is used, the boric acid aqueous solution has a boric acid concentration of, for example, 1% by weight to 15% by weight, preferably 1% by weight to 10% by weight. Further, the boric acid aqueous solution may contain an iodide such as potassium iodide or a zinc compound such as zinc sulfate or zinc chloride.

The crosslinking step can be carried out in any suitable and appropriate manner. For example, a method of immersing a PVA-based resin film in an aqueous solution containing a boron compound, a method of applying an aqueous solution of a boron-containing compound to a PVA-based resin film, or spraying an aqueous solution of a boron-containing compound onto a PVA-based resin film Methods. It is preferably immersed in an aqueous solution containing a boron compound.

The temperature of the solution used for crosslinking is, for example, 25 ° C or higher, preferably 30 ° C to 85 ° C, more preferably 40 ° C to 70 ° C. The immersion time is, for example, 5 seconds to 800 seconds, preferably 8 seconds to 500 seconds.

B-2-6. Washing Step The washing step represents that the upper system is carried out after the crosslinking step. The washing step is carried out by immersing the PVA-based resin film in the cleaning liquid. A representative example of the washing liquid is pure water. Potassium iodide can also be added to pure water.

The temperature of the cleaning solution is, for example, 5 ° C to 50 ° C. The immersion time is, for example, 1 second to 300 seconds.

B-2-7. Drying Step The drying step can be carried out arbitrarily and in an appropriate manner. The drying method may be, for example, natural drying, air drying, reduced pressure drying, heat drying or the like. It is preferred to use heat drying. When heating and drying, the heating temperature is, for example, 30 ° C to 100 ° C. Further, the drying time is, for example, 20 seconds to 10 minutes.

C. Protective film The protective film (and, in the case of another protective film in the presence), any suitable resin film is used. Examples of the material for forming the resin film include a cellulose resin such as (meth)acrylic resin, diethylpyruvium cellulose or triacetyl cellulose, a cycloolefin resin such as a norbornene resin, and an olefin resin such as polypropylene. An ester resin such as a polyethylene terephthalate resin, a polyamide resin, a polycarbonate resin, or a copolymer resin thereof. Further, "(meth)acrylic resin" means an acrylic resin and/or a methacrylic resin.

In one embodiment, the (meth)acrylic resin is a (meth)acrylic resin having a quinodiimine structure. A (meth)acrylic resin (hereinafter also referred to as a pentane quinone imide resin) having a pentylene quinone imine structure is described in the following documents: Japanese Patent Laid-Open Publication No. 2006-309033, No. 2006-317560 Japanese Patent Laid-Open No. 2006-328329, Japanese Laid-Open Patent Publication No. 2006-328334, Japanese Laid-Open Patent Publication No. Hei. No. 2006-337491, Japanese Laid-Open Patent Publication No. Hei. No. 2006-337492, No. 2006-337493 Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. The descriptions are hereby incorporated by reference.

When a polarizer is produced using a laminate of a substrate and a PVA-based resin layer, it can be directly used as a protective film without peeling off the substrate. Further, the polarizing member may be bonded to the protective film after the substrate is peeled off.

Any suitable optical functional film may also be used as the protective film (and, in the presence of another protective film), depending on the purpose. The optical functional film may be, for example, a retardation film or a reflective polarizer (brightness enhancing film).

D. Adhesive Layer The polarizing plate with an adhesive layer according to the embodiment of the present invention is represented as described above, and a protective film is disposed on one side of the polarizing member, and an adhesive layer is disposed on the other side of the polarizing member. That is, in this embodiment, the protective film is not disposed on the other side of the polarizer, and the adhesive layer is directly disposed on the polarizer.

D-1. Adhesive Composition The adhesive composition constituting the adhesive layer contains a base polymer and a conductive agent.

D-1-1. A representative example of the base polymer base polymer is a (meth)acrylic polymer ((meth)acrylic resin). The (meth)acrylic polymer represents a monomer unit derived from an alkyl (meth)acrylate as a main component. An alkyl (meth)acrylate-based (meth)acrylic acid ester. The alkyl group forming the alkyl ester may, for example, be a linear or branched alkyl group having 1 to 18 carbon atoms. Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, a hexyl group, a cyclohexyl group, a heptyl group, a 2-ethylhexyl group, an isooctyl group, and a decyl group. , fluorenyl, isodecyl, dodecyl, isomyristyl, lauryl, thirteen, fifteen, sixteen, seventeen, eighteen. These may be used singly or in combination. The alkyl group contained in the alkyl (meth)acrylate preferably has an average carbon number of from 3 to 9.

The base polymer may also contain monomer units derived from any suitable copolymerization component, depending on the purpose. The copolymerization component may, for example, be a hydroxyl group-containing monomer, a carboxyl group-containing monomer, an acid anhydride group-containing monomer, a sulfonic acid group-containing monomer, a phosphate group-containing monomer, or a (N-substituted) guanamine monomer. Alkylaminoalkyl (meth)acrylate, alkoxyalkyl (meth)acrylate, amber succinimide, maleimide, Ikona An amine monomer, a vinyl monomer, a cyano (meth)acrylate monomer, an epoxy group-containing (meth)acrylic monomer, a glycol (meth)acrylate monomer, or a decane system Monomeric, polyfunctional monomer. By adjusting the kind, amount, combination, and copolymerization ratio (weight ratio) of the copolymerization component, a base polymer (finally an adhesive layer) having desired characteristics can be obtained. The ratio of the copolymerization component in the total monomer component is preferably from 0% by weight to 20% by weight, preferably from 0.1% by weight to 15% by weight, more preferably from 0.1% by weight to 10% by weight, based on 100% by weight of the total monomer component. .

The weight average molecular weight of the base polymer represents 500,000 to 3,000,000, preferably 700,000 to 2.7 million, and preferably 800,000 to 2,500,000. When the weight average molecular weight is too small, heat resistance may be insufficient. If the weight average molecular weight is too large, there is a case where the workability is deteriorated, or a case where a large amount of the solvent is required for the viscosity adjustment of the coating, and the cost increases. Further, the weight average molecular weight means a value measured by GPC (Gel Permeation Chromatography) and calculated in terms of polystyrene.

D-1-2. Conductive Agent The conductive agent contains an inorganic cation salt as described above. The inorganic cation salt is specifically an inorganic cation-anion salt. The cation of the cation portion constituting the inorganic cation salt represents an alkali metal ion. Specific examples thereof include lithium ions, sodium ions, and potassium ions. Preferred is lithium ion. Therefore, a preferred inorganic cation salt is a lithium salt.

The anions of the anion portion constituting the inorganic cation salt are, for example, Cl ^- , Br ^- , I ^- , AlCl ₄ ^- , Al ₂ Cl ₇ ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , NO ₃ ^- , CH ₃ COO ^- , CF ₃ COO ^- , CH ₃ SO ₃ ^- , CF ₃ SO ₃ ^- , (CF ₃ SO ₂ ) ₃ C ^- , AsF ₆ ^- , SbF ₆ ^- , NbF ₆ ^- , TaF ₆ ^- , (CN) ₂ N ^- , C ₄ F ₉ SO ₃ ^- , C ₃ F ₇ COO ^- , (CF ₃ SO ₂ )(CF ₃ CO)N ^- , ^- O ₃ S(CF ₂ ) ₃ SO ₃ ^- , and the following formula (1) ) anion shown by ~(4):
(1): (C _n F _2n+1 SO ₂ ) ₂ N ^- (n is an integer from 1 to 10),
(2): CF ₂ (C _m F _2m SO ₂ ) ₂ N ^- (m is an integer from 1 to 10),
(3): ^- O ₃ S(CF ₂ ) _l SO ₃ ^- (l is an integer from 1 to 10),
(4): (C _p F _2p+1 SO ₂ )N ^- (C _q F _2q+1 SO ₂ ), (p, q is an integer of 1 to 10).
The fluorine-containing anion is preferred, and the fluorine-containing quinone imine is more preferred.

The fluorine-containing quinone imine anion may, for example, be a quinone imine having a perfluoroalkyl group. Specific examples thereof include the above (CF ₃ SO ₂ )(CF ₃ CO)N ^- and the anions represented by the general formulae (1), (2) and (4):
(1): (C _n F _2n+1 SO ₂ ) ₂ N ^- (n is an integer from 1 to 10),
(2): CF ₂ (C _m F _2m SO ₂ ) ₂ N ^- (m is an integer from 1 to 10),
(4): (C _p F _2p+1 SO ₂ )N ^- (C _q F _2q+1 SO ₂ ), (p, q is an integer of 1 to 10).
And (CF ₃ SO ₂ ) ₂ N ^- , (C ₂ F ₅ SO ₂ ) ₂ N ^- and the like (perfluoroalkylsulfonyl) quinone imine represented by the formula (1), especially (CF ₃ SO ₂ ) ₂ N ^{- is} preferably bis(trifluoromethanesulfonyl) ruthenium. Therefore, a preferred inorganic cation salt usable in the embodiment of the present invention is lithium bis(trifluoromethanesulfonyl) ruthenium.

The content of the inorganic cation salt in the adhesive composition (actually, the adhesive layer) is preferably from 0.01 part by weight to 5 parts by weight, preferably from 0.5 part by weight to 3 parts by weight, based on 100 parts by weight of the base polymer. It is more preferably used in parts by weight to 1.5 parts by weight. As long as the content of the inorganic cation salt is within the above range, the moisture resistance of the thin polarizing member having a high iodine content (resulting as a polarizing plate containing the polarizing member) can be remarkably improved.

The conductive agent may further contain an organic cation salt depending on the requirements. By using an inorganic cation salt in combination with an organic cation salt, the surface resistance value can be further lowered without overflowing the inorganic cation salt.

The organic cation salt is specifically an organic cation-anion salt. The cation constituting the cation portion of the organic cation salt represents an organic hydrazine in which a cerium ion is formed by substitution with an organic group. Among the organic oximes, for example, nitrogen-containing ruthenium, sulphur-containing ruthenium, and phosphorus-containing ruthenium may be mentioned Further, it is preferably a nitrogen-containing ruthenium or a ruthenium containing ru The nitrogen-containing ruthenium may, for example, be an ammonium cation, a piperidinium cation, a pyrrolidinium cation, a pyridinium cation, a cation having a dihydropyrrole skeleton, a cation having a pyrrole skeleton, an imidazolium cation, a tetrahydropyrimidinium cation or a dihydropyrimidine. Ruthenium cation, pyrazolium cation, pyrazolinium cation. The ammonium cation, the piperidinium cation, the pyrrolidinium cation are preferred, and the pyrrolidinium cation is more preferred. The sulfur-containing cerium may, for example, be a phosphonium cation The phosphorus-containing cerium may, for example, be a phosphonium cation The organic group in the organic oxime may, for example, be an alkyl group, an alkoxy group or an alkenyl group. Specific examples of the preferred organic oxime include a tetraalkylammonium cation, an alkylpiperidinium cation, and an alkylpyrrolidinium cation. Further, the ethylmethylpyrrolidine cation is more preferred. The anion forming the anion portion of the organic cation salt is as described for the anion of the anion portion constituting the inorganic cation. Therefore, a preferred organic cation salt which can be used in the embodiment of the present invention is a pyrrolidinium salt, and more preferably ethylmethylpyrrolidinium bis(trifluoromethanesulfonyl) ruthenium.

The content of the organic cation salt in the adhesive composition (actually, the adhesive layer) is preferably from 0.1 part by weight to 10 parts by weight, preferably from 0.3 part by weight to 3 parts by weight, based on 100 parts by weight of the base polymer. It is more preferably used in parts by weight to 1.5 parts by weight. When the content of the organic cation salt is in the above range, the combined effect of the above organic cation salt and the inorganic cation salt is remarkable.

D-1-3. The decane couplant adhesive composition may further contain a decane coupling agent. Durability can be improved by using a decane coupling agent. As the decane coupling agent, those having any and appropriate functional groups can be used. Specific examples of the functional group include a vinyl group, an epoxy group, an amine group, a mercapto group, a (meth)acryloxy group, an ethyl oxime group, an isocyanate group, a styryl group, a polysulfide group, and the like. Specific examples thereof include vinyl-containing decane coupling agents such as vinyl triethoxy decane, vinyl tripropoxy decane, vinyl triisopropoxy decane, and vinyl tributoxy decane; and γ-rings; Oxypropoxypropyltrimethoxydecane, γ-glycidoxypropyltriethoxydecane, 3-glycidoxypropylmethyldiethoxydecane, 2-(3,4- Epoxy-containing decane coupling agent such as epoxycyclohexyl)ethyltrimethoxydecane; γ-aminopropyltrimethoxydecane, N-β-(aminoethyl)-γ-aminopropylmethyl dimethyl Oxydecane, N-(2-aminoethyl) 3-aminopropylmethyldimethoxydecane, γ-triethoxyindolyl-N-(1,3-dimethylbutylidene)propylamine, An amine group-containing decane coupling agent such as N-phenyl-γ-aminopropyltrimethoxydecane; a decyl-containing decane coupling agent such as γ-mercaptopropylmethyldimethoxydecane; and p-styrenetrimethoxydecane a styrene-based decane coupling agent; a (meth)acrylic group-containing decane coupling agent such as γ-acryloxypropyltrimethoxydecane or γ-methacryloxypropyltriethoxydecane ; 3-isocyanate propyl triethoxy decane, etc. Silane coupling agent of the ester group; bis (silicon based triethoxysilylpropyl) tetrasulfide polysulfide silicon-containing alkyl group of the coupling agent.

D-1-4. Other adhesive compositions (resulting as an adhesive layer) may also contain any and suitable additives. Specific examples of the additive include a crosslinking agent, a decane coupling agent, a heavy duty lifting agent, an antioxidant, an antistatic agent, a crosslinking retarder, an emulsifier, a colorant, a pigment, a powder, a dye, a surfactant, and a plasticizer. , tackifier, surface lubricant, leveling agent, softener, anti-aging agent, light stabilizer, ultraviolet absorber, polymerization inhibitor, inorganic filler, organic filler, metal powder, granular, foil, etc. . The amount, type, addition amount, and combination of the additives may be appropriately set depending on the purpose.

The method of forming the adhesive layer can be carried out by any suitable method. A typical example of the formation method is a method in which the above-mentioned adhesive composition is applied to a release-treated separator or the like, and a polymerization solvent or the like is dried to form an adhesive layer, and then transferred to a polarizing member. Alternatively, a method in which the above-mentioned adhesive composition is applied to a polarizing member, and a polymerization solvent or the like is dried to form an adhesive layer on the polarizing member. Further, when the adhesive is applied, one or more solvents other than the polymerization solvent may be additionally added as needed.

The details of the adhesive composition are described, for example, in JP-A-2014-48497. The description of this publication is incorporated herein by reference.

D-2. Composition and Characteristics of Adhesive Layer The thickness of the adhesive layer is preferably from 10 μm to 200 μm, more preferably from 10 μm to 100 μm. As long as the thickness of the adhesive layer is within the above range, the effect of improving the moisture resistance by the inorganic cation salt is remarkable.

The surface resistance value (initial) of the pressure-sensitive adhesive layer is preferably 5.0 × 10 ¹¹ Ω·□ or less, and preferably 1.0 × 10 ¹¹ Ω·□ or less, and more preferably 5.0 × 10 ¹⁰ Ω·□ or less. The lower limit of the surface resistance value of the adhesive layer may be, for example, 5.0 × 10 ⁹ Ω·□. As long as the surface resistance value of the adhesive layer is within the above range, there is an advantage that static unevenness is easily suppressed.
Example

Hereinafter, the present invention will be specifically described by examples, but the present invention is not limited by the examples. The measurement method of each characteristic is as follows. In addition, the "parts" and "%" in the examples are the basis of weight unless otherwise noted.

(1) Iodine content The polarizing plate of the polarizing plate with the adhesive layer obtained in the examples and the comparative examples was measured using a fluorescent X-ray analyzer (manufactured by Rigaku Co., Ltd., trade name "ZSX-PRIMUS II").萤 20 mm) The fluorescence X-ray intensity (kcps) was measured. On the other hand, the thickness (μm) of the polarizer was measured using a spectroscopic film thickness meter (manufactured by Otsuka Electronics Co., Ltd., trade name "MCPD-3000"). From the obtained fluorescent X-ray intensity and thickness, the iodine content (% by weight) was determined by the following formula.
(Iodine concentration) = 20.5 × (fluorescent X-ray intensity) / (film thickness)
In addition, the coefficient at which the iodine content is calculated may vary depending on the measuring device, and the coefficient can be obtained using an appropriate calibration curve.
(2) Single-unit transmittance change amount ΔTs
The polarizing plate with the adhesive layer obtained in the examples and the comparative examples was attached to an alkali-free glass having a thickness of 1.3 mm through an adhesive layer to prepare a test sample. The test sample was then humidified for 500 hours at 65 ° C and 90% RH (humidification test). The monomer transmittance Ts ₀ before the test and the monomer transmittance Ts ₅₀₀ after the humidification test were measured by an ultraviolet-visible spectrophotometer (product name: V7100, manufactured by JASCO Corporation) with an integrating sphere. Then, the monomer transmittance change amount ΔTs was obtained from the monomer transmittance Ts ₀ before humidification and the monomer transmittance Ts ₅₀₀ after the humidification test by the following formula.
ΔTs(%)=Ts ₅₀₀ -Ts ₀
(3) The amount of change in polarization degree ΔP
For the polarizing plate with the adhesive layer obtained in the examples and the comparative examples, the transmittance of the monomer Ts and the parallel transmittance were measured by an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, product name: V7100) with an integrating sphere. Tp and orthogonal transmittance Tc. These Ts, Tp, and Tc are measured by a 2 degree field of view (C light source) of JIS Z8701, and the Y value obtained by correcting the optical performance. From the obtained Tp and Tc, the degree of polarization P was obtained by the following formula.
Polarization P(%)={(Tp-Tc)/(Tp+Tc)} ^1/2 ×100
Then, the amount of change in polarization degree ΔP was obtained by the following formula.
ΔP(%)=P ₅₀₀ -P ₀
Here, P ₀ is the degree of polarization before humidification, and P ₅₀₀ is the degree of polarization after leaving it at 65 ° C and 90% RH for 500 hours.
(4) Hue change Δab
For the polarizing plates with the adhesive layer obtained in the examples and the comparative examples, the a value and the b value were measured by an ultraviolet-visible spectrophotometer (V-7100 manufactured by JASCO Corporation) equipped with an integrating sphere. And take it as a ₀ value and b ₀ value. The a ₅₀₀ value and the b ₅₀₀ value after humidification for 500 hours at 65 ° C and 90% RH were determined. The hue change amount Δab is obtained from the equivalent value by the following formula.
Δab={(a ₅₀₀ -a ₀ ) ² +(b ₅₀₀ -b ₀ ) ² } ^1/2
(5) Surface resistance value After the separation film of the polarizing plate with the adhesive layer obtained in the examples and the comparative examples was peeled off, the surface resistance value (Ω·□) of the surface of the adhesive was measured using MCP-HT450 manufactured by Mitsubishi Chemical Analytech Co., Ltd. (initial). After the polarizing plate with the adhesive layer was humidified at 65 ° C and 90% RH for 48 hours, the surface resistance value of the surface of the adhesive was measured in the same manner (after the humidification test). Further, the humidification test was carried out by introducing a polarizing plate with an adhesive layer into a constant temperature and humidity machine at 65 ° C and 90% RH.

[Example 1]
(modulating the base polymer of the adhesive composition)
A monomer mixture containing 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl acrylate was fed into a 4-necked flask equipped with a stirring blade, a thermometer, a nitrogen introduction tube, and a cooler. Then, 0.1 part of 2,2 ́-azobisisobutyronitrile as a polymerization initiator was fed with ethyl acetate in an amount of 100 parts of the monomer mixture (solid content), and nitrogen gas was introduced while stirring slowly. After the nitrogen substitution, the liquid temperature in the flask was maintained at about 60 ° C, and the polymerization reaction was carried out for 7 hours. Then, ethyl acetate was added to the obtained reaction liquid to adjust the solid content concentration to 30%. In the above manner, a solution of an acrylic polymer (A-1) (base polymer) having a weight average molecular weight of 1.4 million was prepared.

(modulating the adhesive composition)
Lithium bis(trifluoromethanesulfonyl) phthalimide (manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.) 1.0 as a conductive agent was blended with respect to 100 parts of the solid content of the above acrylic polymer (A-1) solution. And ethylmethylpyrrolidinium bis(trifluoromethanesulfonyl) quinone imine (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.7 parts, trimethylolpropane diisocyanate as a crosslinking agent (Mitsui Chemical Co., Ltd.) System: TAKENATE D110N) 0.095 parts and 0.3 parts of diphenylguanidinium peroxide, 0.2 parts of organic decane (made by Amika Chemical Co., Ltd.: A100) as a decane coupling agent, and a decane coupling agent containing a thiol group (manufactured by Shin-Etsu Chemical Co., Ltd.: X41-1810) 0.2 parts, 0.03 parts of a heavy duty lifting agent (Silyl SAT10, manufactured by KANEKA CORPORATION), and 0.3 parts of an antioxidant (Irganox 1010, manufactured by BASF Corporation) were prepared to prepare an adhesive composition (solution).

(making a polarizing plate)
As the thermoplastic resin substrate, an amorphous isodecanoic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 μm) having a water absorption of 0.75% and a Tg of 75 ° C was used. Corona treatment was applied to one side of the substrate, and coated on the corona treated surface at 25 ° C to contain polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetamidine at a ratio of 9:1. Ethyl hydrazide modified PVA (degree of polymerization 1200, acetylated ethyl sulfonate degree 4.6%, saponification degree 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIMER Z200") was dried and dried. On the other hand, a PVA-based resin layer having a thickness of 11 μm was formed to produce a laminate.
The obtained laminated body was stretched in a space of 4.5 times in the direction orthogonal to the longitudinal direction of the laminated body at 140 ° C by a tenter stretching machine (extension treatment).
Next, the layered body was immersed in a dye bath (an aqueous solution having an iodine concentration of 1.4% by weight and a potassium iodide concentration of 9.8% by weight) at a liquid temperature of 25 ° C for 12 seconds to carry out dyeing (dyeing treatment).
Next, the layered body was immersed in a washing bath (pure water) having a liquid temperature of 25 ° C for 6 seconds (first washing treatment).
Thereafter, the mixture was immersed in a crosslinking bath having a liquid temperature of 60 ° C (an aqueous solution having a boron concentration of 1% by weight and a potassium iodide concentration of 1% by weight) for 16 seconds (crosslinking treatment).
Next, the laminate was immersed in a washing bath (aqueous solution having a potassium iodide concentration of 1% by weight) at a liquid temperature of 25 ° C for 3 seconds (second washing treatment).
The laminate was then dried in an oven at 60 ° C for 21 seconds (drying treatment).
In the above manner, a laminate (polarizing plate) having a PVA-based resin layer (polarizer) having a thickness of 1.2 μm was obtained. The polarizing member of the obtained polarizing plate had an iodine content of 20.9% by weight and a monomer transmittance of 40.3%.

(Making a polarizing plate with an adhesive layer)
The above adhesive composition was uniformly applied to the surface of a poly(ethylene terephthalate) film (separator) treated with a polyfluorene-based release agent by a spray coater, and circulated at 155 ° C in air. The oven was dried for 2 minutes, and an adhesive layer having a thickness of 20 μm was formed on the surface of the separator. Then, the adhesive layer was transferred onto the surface of the polarizer of the above polarizing plate to prepare a polarizing plate with an adhesive layer.

The obtained polarizing plate with the adhesive layer was supplied for the evaluation of the above (2) to (5). The results are listed in Table 1.

[Embodiment 2]
The adhesive composition was prepared in the same manner as in Example 1 except that only 0.2 part of A100 was used as the decane coupling agent. A polarizing plate with an adhesive layer was prepared in the same manner as in Example 1 except that the adhesive composition was used. The obtained polarizing plate with the adhesive layer was supplied for the same evaluation as in Example 1. The results are listed in Table 1.

[Example 3]
The adhesive composition was prepared in the same manner as in Example 1 except that only 1.0 part of lithium bis(trifluoromethanesulfonyl) ruthenium was used as the conductive agent. A polarizing plate with an adhesive layer was prepared in the same manner as in Example 1 except that the adhesive composition was used. The obtained polarizing plate with the adhesive layer was supplied for the same evaluation as in Example 1. The results are listed in Table 1.

[Example 4]
The adhesive composition was prepared in the same manner as in Example 1 except that only 1.0 part of lithium bis(trifluoromethanesulfonyl) ruthenium was used as the conductive agent and only 0.2 part of A100 was used as the decane coupling agent. A polarizing plate with an adhesive layer was prepared in the same manner as in Example 1 except that the adhesive composition was used. The obtained polarizing plate with the adhesive layer was supplied for the same evaluation as in Example 1. The results are listed in Table 1.

[Comparative Example 1]
The adhesive composition was prepared in the same manner as in Example 1 except that only 0.7 part of ethylmethylpyrrolidinium bis(trifluoromethanesulfonyl) quinone was used as the conductive agent. A polarizing plate with an adhesive layer was prepared in the same manner as in Example 1 except that the adhesive composition was used. The obtained polarizing plate with the adhesive layer was supplied for the same evaluation as in Example 1. The results are listed in Table 1.

[Comparative Example 2]
Adhesion was prepared in the same manner as in Example 1 except that only 0.7 parts of ethylmethylpyrrolidinium bis(trifluoromethanesulfonyl) quinone was used as the conductive agent and only 0.2 part of A100 was used as the decane coupling agent. Agent composition. A polarizing plate with an adhesive layer was prepared in the same manner as in Example 1 except that the adhesive composition was used. The obtained polarizing plate with the adhesive layer was supplied for the same evaluation as in Example 1. The results are listed in Table 1.

[Comparative Example 3]
The adhesive composition was prepared in the same manner as in Example 1 except that the conductive agent was not used. A polarizing plate with an adhesive layer was prepared in the same manner as in Example 1 except that the adhesive composition was used. The obtained polarizing plate with the adhesive layer was supplied for the same evaluation as in Example 1. The results are listed in Table 1.

[Table 1]

As is apparent from Table 1, the polarizing plate with the adhesive layer of the embodiment of the present invention has excellent single transmittance change, polarization change, and hue change after the humidification test, and has excellent moisture resistance. .

Industrial Applicability The polarizing member of the present invention can be widely applied to liquid crystal televisions, liquid crystal displays, mobile phones, digital cameras, digital cameras, handheld game machines, car navigation, photocopying machines, printers, facsimile machines, clocks, On a liquid crystal panel such as a microwave oven.

10‧‧‧ polarizer

20‧‧‧Protective film

30‧‧‧Adhesive layer

100‧‧‧Polarizer with adhesive layer

Fig. 1 is a schematic cross-sectional view showing a polarizing plate with an adhesive layer according to an embodiment of the present invention.

Claims (7)

A polarizing plate with an adhesive layer, comprising: a polarizing member; a protective film disposed on one side of the polarizing member; and an adhesive layer disposed on the other side of the polarizing member; The polarizing member has an iodine content of 10% by weight to 25% by weight; The adhesive layer contains a conductive agent; The conductive agent contains an inorganic cation salt. The polarizing plate of the adhesive layer of claim 1, wherein the inorganic cation salt is a lithium salt. The polarizing plate with an adhesive layer according to claim 1 or 2, wherein the anion of the anion portion constituting the inorganic cation salt is selected from the anions represented by the following general formulae (1) to (4): (1): C _n F _2n+1 SO ₂ ) ₂ N ^- (n is an integer from 1 to 10), (2): CF ₂ (C _m F _2m SO ₂ ) ₂ N ^- (m is an integer from 1 to 10), ( 3): ^- O ₃ S(CF ₂ ) _l SO ₃ ^- (l is an integer from 1 to 10), (4): (C _p F _2p+1 SO ₂ )N ^- (C _q F _2q+1 SO ₂ ), (p, q is an integer from 1 to 10). The polarizing plate with an adhesive layer according to any one of claims 1 to 3, wherein the inorganic cation salt is contained in an amount of from 0.01 part by weight to 5 parts by weight per 100 parts by weight of the base polymer of the adhesive layer. The polarizing plate with an adhesive layer according to any one of claims 1 to 4, wherein the conductive agent further comprises an organic cation salt. The polarizing plate with the adhesive layer of claim 5, wherein the content of the organic cation salt is from 0.1 part by weight to 10 parts by weight based on 100 parts by weight of the base polymer of the adhesive layer. The polarizing plate with an adhesive layer according to any one of claims 1 to 6, wherein the polarizing member has a thickness of 3 μm or less.