KR20230104539A - Polarizing plate and image display device using the same - Google Patents

Abstract

In spite of having a low-resistance pressure-sensitive adhesive layer, a polarizing plate having a thin shape, excellent durability, poor appearance is suppressed, and cracks during release processing are suppressed. A polarizing plate according to an embodiment of the present invention includes a polarizer, a protective layer provided on one side of the polarizer, an iodine permeation suppression layer provided on the other side of the polarizer, and an adhesive layer provided on the opposite side of the iodine permeation suppression layer to the polarizer. . The iodine permeation inhibiting layer is a solidified product or a thermoset product of a coating film of an organic solvent solution of a resin. The pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer contains a base polymer and an antistatic agent, the base polymer has a glass transition temperature of -50°C or less, and a dielectric constant of 5.0 or more at 100 kHz, and a surface resistance value of the pressure-sensitive adhesive layer. is less than 1.0×10 ⁹ Ω/□.

Description

Polarizing plate and image display device using the same

The present invention relates to a polarizing plate and an image display device using the same.

BACKGROUND OF THE INVENTION Image display devices typified by liquid crystal display devices and electroluminescent (EL) display devices (eg, organic EL display devices and inorganic EL display devices) are rapidly spreading. In an image display device, typically, a polarizing plate is bonded to a display panel via an adhesive layer. In recent years, with the narrowing of the frame width of image display devices and the development of so-called in-cell type image display devices incorporating conductive layers for touch panels in display panels, improvement in antistatic performance of image display devices has been demanded. As a result, improvement in the antistatic performance of the pressure-sensitive adhesive layer and reduction in resistance are required. However, in a polarizing plate using such an adhesive layer, there are problems such as decrease in durability of the polarizing plate, poor appearance, and generation of cracks when processing the polarizing plate into a release shape other than rectangular.

Japanese Unexamined Patent Publication No. 2015-193371

The present invention has been made to solve the above conventional problems, and its main object is, despite having a low-resistance adhesive layer, it is thin, has excellent durability, suppresses appearance defects, and cracks during mold release processing It is to provide this suppressed polarizing plate.

A polarizing plate according to an embodiment of the present invention includes a polarizer, a protective layer provided on one side of the polarizer, an iodine permeation inhibiting layer provided on the other side of the polarizer, and an iodine permeation inhibiting layer provided on the opposite side of the polarizer. It has an adhesive layer. The said iodine permeation suppression layer is a solidified material or thermoset material of the coating film of the organic solvent solution of resin. The pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer contains a base polymer and an antistatic agent, the base polymer has a glass transition temperature of -50°C or less, and a dielectric constant of 5.0 or more at 100 kHz, and the The surface resistance value is 1.0×10 ⁹ Ω/□ or less.

In one embodiment, the base polymer contains an alkoxy group-containing monomer as a monomer component. In one embodiment, the base polymer contains 20 parts by weight to 99 parts by weight of the alkoxy group-containing monomer with respect to 100 parts by weight of all monomer components. In one embodiment, the alkoxy group-containing monomer is represented by the following formula:

In formula, R ^<1> is an alkyl group, and n is an integer of 1-15.

In one embodiment, the base polymer further contains a hydroxyl group-containing monomer as a monomer component.

In one embodiment, the content of the antistatic agent in the pressure-sensitive adhesive composition is 10 parts by weight or less with respect to 100 parts by weight of the base polymer.

In one embodiment, the antistatic agent is lithium bis (trifluoromethanesulfonyl) imide, 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide or tributylmethylammonium bis ( trifluoromethanesulfonyl)imide.

In one embodiment, the said adhesive composition further contains a silane coupling agent. In one embodiment, the said adhesive composition further contains antioxidant.

In one embodiment, the adhesive force with respect to glass of the said adhesive layer is 1.0 N/25 mm or more.

In one embodiment, the resin constituting the iodine permeation inhibiting layer is a monomer containing more than 50 parts by weight of a (meth)acrylic monomer and more than 0 part by weight and less than 50 parts by weight of a monomer represented by formula (1) It includes copolymers obtained by polymerizing the mixture:

(Wherein, X is selected from the group consisting of a vinyl group, a (meth)acrylic group, a styryl group, a (meth)acrylamide group, a vinylether group, an epoxy group, an oxetane group, a hydroxyl group, an amino group, an aldehyde group, and a carboxyl group represents a functional group containing at least one reactive group, and R ¹ and R ² are each independently a hydrogen atom, an aliphatic hydrocarbon group which may have a substituent, an aryl group which may have a substituent, or a hetero which may have a substituent represents ventilation, and R ¹ and R ² may be connected to each other to form a ring).

In one embodiment, the polarizing plate has a total thickness of 60 μm or less.

According to another aspect of the present invention, an image display device is provided. This image display device is provided with the polarizing plate described above.

According to an embodiment of the present invention, in a polarizing plate having a low-resistance pressure-sensitive adhesive layer, by making the pressure-sensitive adhesive layer a specific configuration, it is thin, has excellent durability, and has poor appearance (typically, partial swelling of the protective layer included in the polarizing plate) and cracks in the functional layer) are suppressed, and a polarizing plate in which cracks are suppressed during release processing can be realized.

1 is a schematic cross-sectional view of a polarizing plate according to one embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, although embodiment of this invention is described, this invention is not limited to these embodiment.

A. Overall composition of the polarizer

1 is a schematic cross-sectional view of a polarizing plate according to one embodiment of the present invention. The polarizing plate 100 of the illustrated example includes a polarizer 11, a protective layer 12 provided on one side of the polarizer 11, an iodine transmission suppression layer 40 provided on the other side of the polarizer 11, and iodine It has a pressure-sensitive adhesive layer 30 provided on the opposite side of the polarizer 11 of the transmission suppression layer 40 . The iodine permeation inhibiting layer 40 is a solidified product or a thermoset product of a coating film of an organic solvent solution of a resin. Between the polarizer 11 and the iodine transmission suppression layer 40, another protective layer (not shown) may be provided. Preferably, as shown in the illustration, the protective layer 12 is provided only on one side of the polarizer 11 . In this case, the iodine transmission suppression layer 40 is provided directly on the polarizer 11 on the other side of the polarizer 11 . In this specification, "it is provided directly to the polarizer" means that it is directly formed on the surface of the polarizer without an adhesive layer (typically, an adhesive layer or an adhesive layer) interposed therebetween. The adhesive layer 30 is provided as an outermost layer, and the polarizing plate can be attached to an image display device (substantially, an image display panel). Practically, it is preferable that a peeling film is temporarily attached to the surface of the pressure-sensitive adhesive layer 30 until the polarizing plate is put into use. Roll formation of a polarizing plate becomes possible while protecting an adhesive layer by temporarily attaching a peeling film.

In the embodiment of the present invention, the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer 30 contains a base polymer and an antistatic agent. The base polymer has a glass transition temperature of -50°C or lower, and a permittivity of 5.0 or higher at 100 kHz. By using such a base polymer, it is possible to realize a pressure-sensitive adhesive layer having a small surface resistance value in spite of the small content of the antistatic agent. That is, in the embodiment of the present invention, the content of the antistatic agent in the pressure-sensitive adhesive composition is less than 10 parts by weight based on 100 parts by weight of the base polymer, and the surface resistance value of the pressure-sensitive adhesive layer is 1.0 × 10 ⁹ Ω/□ or less. can As a result, it is possible to realize a polarizing plate that is thin, has excellent durability, suppresses appearance defects of functional layers (eg, iodine permeation suppression layer) included in the polarizing plate, and suppresses cracks during release processing.

The polarizing plate according to the embodiment of the present invention may further include functional layers other than the iodine permeation suppression layer. A typical example of such a functional layer is a phase difference layer. Optical characteristics (eg, refractive index characteristics, in-plane retardation, Nz coefficient, photoelastic coefficient), thickness, placement position, etc. of the retardation layer may be appropriately set depending on the purpose.

The polarizing plate according to the embodiment of the present invention may have a sheet shape or a long shape. In this specification, "elongated shape" means an elongated shape whose length is sufficiently long compared to the width, and includes, for example, an elongated shape whose length is 10 times or more, preferably 20 times or more compared to the width. The elongated polarizing plate can be wound in a roll shape.

The polarizing plate according to the embodiment of the present invention may have a release shape other than a rectangle. In this specification, "it has a non-rectangular shape" means that the planar view shape of a polarizing plate has a shape other than a rectangle. The mold release is typically a mold release processing part subjected to mold release processing. Therefore, "a polarizing plate having a release shape other than rectangular" is not only a case where the entire polarizing plate (ie, the outer edge defining the planar view shape of the film) is other than a rectangular shape, but also a release shape in a portion spaced inward from the outer edge of the rectangular polarizing plate. The case where a processing part is formed is also included. In the case of using a pressure-sensitive adhesive layer (low-resistance pressure-sensitive adhesive layer) having a small surface resistance value, the added antistatic agent acts as a plasticizer, and cracks occur in the polarizer due to shrinkage of the polarizer in a high-temperature environment in such a release processing part. In terms of simplicity, according to the embodiment of the present invention, such cracks can be remarkably suppressed. As a release (release processing part), a through-hole, chamfering of a corner part, and a cutting part used as a concave part in planar view are mentioned, for example. Representative examples of the concave portion include a shape approximating a pear shape, a shape approximating a bathtub, a V-shaped notch, and a U-shaped notch. Another example of the mold release (release processing part) is a shape corresponding to an automobile meter panel. The shape includes a region where the outer edge is formed in an arc shape along the rotational direction of the meter needle and the outer edge forms a V-shape (including an R shape) convex inward in the plane direction. The shape of the release is not limited to the above example, and any suitable shape may be employed depending on the purpose. For example, as the shape of the through hole, a circle, an ellipse, a triangle, a quadrangle, a pentagon, a hexagon, or an octagon may be employed. In addition, the through hole is provided in an arbitrary appropriate position depending on the purpose. The through hole may be provided at a substantially central portion of the longitudinal direction end portion of the rectangular polarizing plate, may be provided at a predetermined position at the longitudinal direction end portion, or may be provided at a corner portion of the polarizing plate; It may be provided at the short side end of the rectangular polarizing plate; The whole may be provided in the central part of the polarizing plate which has a release shape. The mold release processing part may be formed by combining the forms of the above examples. For example, you may form combining a through hole, a V-shaped notch, and/or a U-shaped notch.

The total thickness of the polarizing plate is preferably 60 μm or less, more preferably 55 μm or less, still more preferably 50 μm or less, and particularly preferably 40 μm or less. The lower limit of the total thickness may be, for example, 28 μm. According to embodiment of this invention, in the structure which has a low-resistance adhesive layer and has a protective layer only on one side of a polarizer, the effect equivalent to the structure which has a protective layer on both sides of a polarizer can be acquired. As a result, since one protective layer can be omitted, remarkable thinning can be realized. If the total thickness of the polarizing plate is within this range, generation of air bubbles, so-called delay bubbles, can be remarkably suppressed. A delay bubble refers to a bubble generated in the following situations. For example, when a polarizing plate with a through hole is bonded to the viewing side of an image display panel, a cover glass may be bonded to the viewing side of the polarizing plate. The cover glass is bonded by vacuum lamination via a predetermined pressure sensitive adhesive. At this time, the through hole may be filled with the adhesive. Immediately after vacuum lamination, there are many cases where there are no recognizable bubbles in the filling portion, but there are cases where bubbles are generated in the subsequent heating endurance test of the image display device. Such bubbles can typically be generated when shrinkage stress of the polarizing plate is applied to the filling part. Such bubbles are called delay bubbles. Delay bubbles are not minute, but large, occupying a certain percentage or more of the planar area of the through hole, and are difficult to accept from the viewpoint of appearance and camera performance of the camera unit provided at the position corresponding to the through hole. Therefore, suppression of delay bubbles has high industrial value. In addition, the total thickness of the polarizing plate refers to the total thickness of the polarizer, the protective layer, the iodine permeation suppression layer, and the adhesive layer or pressure-sensitive adhesive layer for laminating them (ie, the total thickness of the polarizing plate is the pressure-sensitive adhesive layer 30 and its It does not include the thickness of the release film that can be adhered to the surface).

Hereinafter, the components of the polarizing plate will be described in more detail.

B. Polarizer

The polarizer is typically made of a resin film containing a dichroic substance (typically, iodine). As the resin film, any suitable resin film that can be used as a polarizer can be employed. The resin film is typically a polyvinyl alcohol-based resin (hereinafter referred to as "PVA-based resin") film. The resin film may be a single layer resin film or a laminate of two or more layers.

As a specific example of the polarizer comprised from the resin film of a single layer, the thing to which the dyeing process by iodine and the extending|stretching process (typically uniaxial stretching) were given to the PVA system resin film is mentioned. The dyeing with iodine is performed, for example, by immersing the PVA-based film in an aqueous solution of iodine. The draw ratio of the uniaxial stretching is preferably 3 to 7 times. Stretching may be performed after dyeing treatment, or may be performed while dyeing. Moreover, you may dye after extending|stretching. Swelling treatment, crosslinking treatment, washing treatment, drying treatment and the like are given to the PVA-based resin film as necessary. For example, by immersing the PVA-based resin film in water and washing it with water before dyeing, not only can dirt and anti-blocking agents on the surface of the PVA-based film be washed, but also swelling of the PVA-based resin film can prevent uneven coloring and the like. .

As a specific example of a polarizer obtained using a laminate, a laminate of a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a laminate of a resin substrate and a PVA-based resin layer applied and formed on the resin substrate A polarizer obtained using a sieve is exemplified. A polarizer obtained by using a laminate of a resin substrate and a PVA-based resin layer coated and formed on the resin substrate, for example, by applying a PVA-based resin solution to the resin substrate, drying it, and forming a PVA-based resin layer on the resin substrate. , Obtaining a laminate of a resin substrate and a PVA-based resin layer; It can be produced by: stretching and dyeing the layered product to make the PVA-based resin layer a polarizer. In the present embodiment, preferably, a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin is formed on one side of the resin substrate. Stretching typically involves immersing the layered product in an aqueous solution of boric acid, followed by stretching. Further, the stretching may further include, if necessary, air stretching of the laminate at a high temperature (eg, 95° C. or higher) before stretching in a boric acid aqueous solution. Further, in the present embodiment, the laminate is preferably subjected to a drying shrinkage treatment in which the laminate is shrunk by 2% or more in the width direction by heating while conveying in the longitudinal direction. Typically, the manufacturing method of this embodiment includes giving the laminated body an air assisted stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment in this order. By introducing auxiliary stretching, even when applying PVA on a thermoplastic resin, it becomes possible to improve the crystallinity of PVA and achieve high optical properties. In addition, by simultaneously increasing the orientation of PVA in advance, it is possible to prevent problems such as deterioration in orientation or dissolution of PVA when immersed in water in a subsequent dyeing step or drawing step, and to achieve high optical properties. It happens. Further, in the case where the PVA-based resin layer is immersed in a liquid, the disorder of the orientation of polyvinyl alcohol molecules and the decrease in orientation can be suppressed compared to the case where the PVA-based resin layer does not contain a halide. Thereby, the optical characteristics of the polarizer obtained through the processing process performed by immersing a layered product in liquid, such as a dyeing process and an underwater extension process, can be improved. In addition, optical properties can be improved by shrinking the laminate in the width direction by drying shrinkage treatment. The obtained laminate of the resin substrate/polarizer may be used as it is (that is, the resin substrate may be used as a protective layer for the polarizer), and the resin substrate is peeled from the laminate of the resin substrate/polarizer, and the peeling surface is optionally used according to the purpose. An appropriate protective layer of may be laminated and used. The detail of the manufacturing method of such a polarizer is described in Unexamined-Japanese-Patent No. 2012-73580 and Japanese Patent No. 6470455, for example. As for these publications, the entire description is incorporated herein by reference.

The thickness of the polarizer is preferably 1 μm to 10 μm, more preferably 1 μm to 8 μm, still more preferably 2 μm to 5 μm. If the thickness of the polarizer is within this range, it can greatly contribute to the thinning of the polarizing plate.

The polarizer preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The single transmittance of the polarizer is preferably 41.5% to 46.0%, more preferably 43.0% to 46.0%, still more preferably 44.5% to 46.0%. The degree of polarization of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, still more preferably 99.9% or more.

C. protective layer

The protective layer 12 (and another protective layer, if present) is formed of any appropriate film that can be used as a protective layer for a polarizer. Specific examples of the material used as the main component of the film include cellulose-based resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, and polyether alcohol. and transparent resins such as phonon-based, polysulfone-based, polystyrene-based, polynorbornene-based, polyolefin-based, (meth)acrylic-based, and acetate-based resins. Further, thermosetting resins such as (meth)acrylic, urethane-based, (meth)acrylurethane-based, epoxy-based, and silicone-based resins or ultraviolet curable resins may be used. In addition, glassy type polymers, such as a siloxane type polymer, are also mentioned, for example. Moreover, the polymer film of Unexamined-Japanese-Patent No. 2001-343529 (WO01/37007) can also be used. As the material of this film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in its side chain, a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in its side chain can be used. For example, and a resin composition comprising an alternating copolymer of isobutene and N-methylmaleimide, and an acrylonitrile/styrene copolymer. The polymer film may be, for example, an extrusion molding of the resin composition.

When the polarizing plate is disposed on the viewing side of the image display device, the protective layer 12 is typically disposed on the viewing side. In this case, the protective layer 12 may be subjected to surface treatment such as hard coat treatment, antireflection treatment, anti-sticking treatment, and antiglare treatment, if necessary.

The thickness of the protective layer is preferably 10 μm to 50 μm, more preferably 15 μm to 35 μm. In addition, when the surface treatment is performed, the thickness of the outer protective layer is the thickness including the thickness of the surface treatment layer.

D. Iodine Permeation Inhibiting Layer

In the embodiment of the present invention, by providing an iodine permeation suppression layer, it is possible to suppress an increase in the surface resistance value of the pressure-sensitive adhesive layer in a high-temperature environment and/or a high-temperature/high-humidity environment, and cracks during release processing. can suppress As described above, the iodine permeation inhibiting layer is a solidified product or a thermoset product of a coating film of an organic solvent solution of a resin. With such a configuration, the thickness can be made very thin (for example, 10 μm or less). The thickness of the iodine permeation inhibiting layer is preferably 0.05 μm to 10 μm, more preferably 0.08 μm to 5 μm, still more preferably 0.1 μm to 1 μm, and particularly preferably 0.2 μm to 0.7 μm. . In addition, with such a structure, the iodine permeation suppression layer can be formed directly on the polarizer (ie, without an adhesive layer or pressure-sensitive adhesive layer interposed therebetween). According to the embodiment of the present invention, as described above, since the polarizer and the iodine permeation suppression layer are very thin, and the adhesive layer or the pressure-sensitive adhesive layer for laminating the iodine permeation suppression layer can be omitted, the total thickness of the polarizing plate can be made very thin. can In addition, such an iodine permeation inhibiting layer has an advantage of excellent humidification durability because it has lower hygroscopicity and moisture permeability than a solidified product of an aqueous coating film such as an aqueous solution or an aqueous dispersion. As a result, a polarizing plate excellent in durability capable of maintaining optical properties even under a high-temperature, high-humidity environment can be realized. In addition, such an iodine permeation suppression layer can suppress adverse effects on a polarizing plate (polarizer) by ultraviolet irradiation compared to, for example, a cured product of an ultraviolet curable resin. The iodine permeation inhibiting layer is preferably a solidified product of a coating film of an organic solvent solution of a resin. The solidified material has less shrinkage during film molding than the cured material, and since no residual monomer or the like is contained, deterioration of the film itself is suppressed, and adverse effects on the polarizing plate (polarizer) due to the residual monomer or the like can be suppressed. there is.

The glass transition temperature (Tg) of the resin constituting the iodine permeation inhibiting layer is typically 85°C or higher, preferably 90°C or higher, more preferably 100°C or higher, still more preferably 110°C or higher. , particularly preferably 120°C or higher. The upper limit of Tg may be, for example, 200°C. The weight average molecular weight Mw of the resin is typically 25000 or more, preferably 30000 or more, more preferably 35000 or more, still more preferably 40000 or more. The upper limit of Mw may be, for example, 150000. If the Tg and Mw of the resin are within these ranges, the polarizer, despite being very thin, has a synergistic effect with the effect of constituting the iodine permeation suppression layer with a solidified product or a thermoset product of a coating film of an organic solvent solution of the resin. The transfer of iodine to the image display panel can be remarkably suppressed. As a result, when the polarizing plate is applied to the image display device, corrosion of the metal member of the image display device can be remarkably suppressed.

As the resin constituting the iodine permeation inhibiting layer, any suitable thermoplastic resin or thermosetting resin can be used. Preferably, it is a thermoplastic resin. As a thermoplastic resin, an acrylic resin and an epoxy resin are mentioned, for example. An acrylic resin and an epoxy resin may be used in combination. Hereinafter, representative examples of acrylic resins and epoxy resins that can be used for the iodine permeation inhibiting layer will be described.

Acrylic resin typically contains, as a main component, a repeating unit derived from a (meth)acrylic acid ester monomer having a linear or branched structure. In this specification, a (meth)acryl refers to an acryl and/or methacryl. The acrylic resin may contain a repeating unit derived from any suitable copolymerizable monomer depending on the purpose. Examples of copolymerization monomers (copolymerization monomers) include carboxyl group-containing monomers, hydroxyl group-containing monomers, amide group-containing monomers, aromatic ring-containing (meth)acrylates, and heterocyclic-containing vinyl monomers. By appropriately setting the type, number, combination and copolymerization ratio of monomer units, an acrylic resin having the predetermined Mw can be obtained.

<Boron-containing acrylic resin>

In one embodiment, the acrylic resin is a (meth)acrylic monomer exceeding 50 parts by weight and a monomer represented by formula (1) exceeding 0 parts by weight and less than 50 parts by weight (hereinafter sometimes referred to as a copolymerization monomer) It includes a copolymer (hereinafter sometimes referred to as a boron-containing acrylic resin) obtained by polymerizing a monomer mixture containing:

(Wherein, X is selected from the group consisting of a vinyl group, a (meth)acrylic group, a styryl group, a (meth)acrylamide group, a vinylether group, an epoxy group, an oxetane group, a hydroxyl group, an amino group, an aldehyde group, and a carboxyl group represents a functional group containing at least one reactive group, and R ¹ and R ² are each independently a hydrogen atom, an aliphatic hydrocarbon group which may have a substituent, an aryl group which may have a substituent, or a hetero which may have a substituent represents ventilation, and R ¹ and R ² may be connected to each other to form a ring).

Boron-containing acrylic resin typically has a repeating unit represented by the following formula. By polymerizing a monomer mixture containing a copolymerization monomer represented by Formula (1) and a (meth)acrylic monomer, the boron-containing acrylic resin has a boron-containing substituent in the side chain (for example, a repeating unit of k in the following formula) have Thereby, when an iodine transmission suppression layer is arrange|positioned adjacent to a polarizer, adhesiveness with a polarizer can be improved. The boron-containing substituent may be continuously (ie, in a block shape) or randomly included in the boron-containing acrylic resin.

(In the formula, R ⁶ represents an arbitrary functional group, and j and k represent integers greater than or equal to 1).

<(meth)acrylic monomer>

Any appropriate (meth)acrylic monomer can be used as the (meth)acrylic monomer. For example, a (meth)acrylic acid ester type monomer having a linear or branched structure and a (meth)acrylic acid ester type monomer having a cyclic structure are exemplified.

Examples of the (meth)acrylic acid ester monomer having a straight chain or branched structure include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, and n (meth)acrylate. -Butyl, isobutyl (meth)acrylate, t-butyl (meth)acrylate, methyl 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate and the like. Preferably, methyl (meth)acrylate is used. The (meth)acrylic acid ester monomer may be used alone or in combination of two or more.

Examples of the (meth)acrylic acid ester monomer having a cyclic structure include cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, 1-adamantyl (meth)acrylate, and (meth)acrylate. Dicyclopentenyl acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, biphenyl (meth)acrylate, o-biphenyloxyethyl (meth)acrylate, o-biphenyloxy Ethoxyethyl (meth)acrylate, m-biphenyloxyethyl acrylate, p-biphenyloxyethyl (meth)acrylate, o-biphenyloxy-2-hydroxypropyl (meth)acrylate, p-bi Phenyloxy-2-hydroxypropyl (meth)acrylate, m-biphenyloxy-2-hydroxypropyl (meth)acrylate, N-(meth)acryloyloxyethyl-o-biphenyl = carbamate , N-(meth)acryloyloxyethyl-p-biphenyl=carbamate, N-(meth)acryloyloxyethyl-m-biphenyl=carbamate, o-phenylphenol glycidyl ether acrylate Biphenyl group-containing monomers, such as a rate, terphenyl (meth)acrylate, o-terphenyloxyethyl (meth)acrylate, etc. are mentioned. Preferably, 1-adamantyl (meth)acrylate and dicyclopentanyl (meth)acrylate are used. By using these monomers, a polymer having a high glass transition temperature is obtained. These monomers may be used alone or in combination of two or more.

Moreover, you may use the silsesquioxane compound which has a (meth)acryloyl group instead of the said (meth)acrylic acid ester type monomer. By using a silsesquioxane compound, an acrylic polymer with a high glass transition temperature is obtained. Silsesquioxane compounds are known to have various skeleton structures, for example, cage structures, ladder structures, and random structures. A silsesquioxane compound may have only 1 type of these structures, and may have 2 or more types. Silsesquioxane compounds may be used alone or in combination of two or more.

As a silsesquioxane compound containing a (meth)acryloyl group, MAC grade and AC grade of Toagosei Co., Ltd. SQ series can be used, for example. MAC grade is a silsesquioxane compound containing a methacryloyl group, and specifically, MAC-SQ TM-100, MAC-SQ SI-20, MAC-SQ HDM etc. are mentioned. AC grade is a silsesquioxane compound containing an acryloyl group, and specifically, AC-SQ TA-100, AC-SQ SI-20 etc. are mentioned.

The (meth)acrylic monomer is used in an amount exceeding 50 parts by weight based on 100 parts by weight of the monomer mixture.

<Copolymerization monomer>

As a copolymerization monomer, the monomer represented by said Formula (1) is used. By using such a copolymerization monomer, a substituent containing boron is introduced into the side chain of the resulting polymer. A copolymerization monomer may use only 1 type, and may use it in combination of 2 or more types.

As the aliphatic hydrocarbon group in the above formula (1), a straight-chain or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, a cyclic alkyl group having 3 to 20 carbon atoms which may have a substituent, and an alkenyl group having 2 to 20 carbon atoms. can be heard As said aryl group, the C6-C20 phenyl group which may have a substituent, the C10-C20 naphthyl group which may have a substituent, etc. are mentioned. As a heterocyclic group, the 5-membered ring group or the 6-membered ring group containing at least 1 hetero atom which may have a substituent is mentioned. In addition, R ¹ and R ² may be connected to each other to form a ring. R ¹ and R ² are preferably a hydrogen atom or a straight-chain or branched alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom.

The reactive group included in the functional group represented by X is a vinyl group, a (meth)acrylic group, a styryl group, a (meth)acrylamide group, a vinyl ether group, an epoxy group, an oxetane group, a hydroxyl group, an amino group, an aldehyde group, and a carboxyl group. It is at least one kind selected from the group consisting of. Preferably, the reactive group is a (meth)acrylic group and/or a (meth)acrylamide group. By having these reactive groups, when the iodine permeation suppression layer is disposed adjacent to the polarizer, adhesion to the polarizer can be further improved.

In one embodiment, it is preferable that the functional group represented by X is a functional group represented by Z-Y-. Here, Z is at least selected from the group consisting of a vinyl group, a (meth)acrylic group, a styryl group, a (meth)acrylamide group, a vinylether group, an epoxy group, an oxetane group, a hydroxyl group, an amino group, an aldehyde group, and a carboxyl group. represents a functional group containing one kind of reactive group, and Y represents a phenylene group or an alkylene group.

As a copolymerization monomer, the following compounds can be specifically used.

The copolymerization monomer is used in a content of more than 0 parts by weight and less than 50 parts by weight based on 100 parts by weight of the monomer mixture. Preferably it is 0.01 part by weight or more and less than 50 parts by weight, more preferably 0.05 part by weight to 20 parts by weight, even more preferably 0.1 part by weight to 10 parts by weight, particularly preferably 0.5 part by weight to 5 parts by weight. am.

<Acrylic resin containing lactone ring etc.>

In another embodiment, the acrylic resin is a repeating unit containing a ring structure selected from a lactone ring unit, a glutaric anhydride unit, a glutarimide unit, a maleic anhydride unit, and a maleimide (N-substituted maleimide) unit. may have As for the repeating unit containing ring structure, only 1 type may be included in the repeating unit of acrylic resin, and 2 or more types may be included. The content of the repeating unit containing a ring structure in the acrylic resin is preferably 1 mol% to 50 mol%, more preferably 10 mol% to 40 mol%, still more preferably 20 mol% to 30 mol%. %am. Moreover, acrylic resin contains the repeating unit derived from the said (meth)acrylic-type monomer as a main repeating unit.

<Epoxy resin>

As the epoxy resin, an epoxy resin having an aromatic ring is preferably used. By using an epoxy resin having an aromatic ring as the epoxy resin, when the iodine permeation suppression layer is disposed adjacent to the polarizer, adhesion to the polarizer can be improved. Further, when the pressure-sensitive adhesive layer is disposed adjacent to the iodine permeation inhibiting layer, the anchoring force of the pressure-sensitive adhesive layer can be improved. Examples of the epoxy resin having an aromatic ring include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin; novolak-type epoxy resins such as phenol novolak epoxy resins, cresol novolak epoxy resins, and hydroxybenzaldehyde phenol novolak epoxy resins; Polyfunctional type epoxy resins such as glycidyl ether of tetrahydroxyphenylmethane, glycidyl ether of tetrahydroxybenzophenone, epoxidized polyvinylphenol, naphthol type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin etc. can be mentioned. Preferably, bisphenol A type epoxy resin, biphenyl type epoxy resin, and bisphenol F type epoxy resin are used. An epoxy resin may use only 1 type, and may use it in combination of 2 or more types.

The iodine permeation inhibiting layer may be formed by applying an organic solvent solution of the above resin to form a coating film, and solidifying or thermally curing the coating film. As the application method, solidification or curing conditions, any suitable method and conditions can be employed.

The iodine permeation suppression layer (actually, the organic solvent solution of the resin) may contain any suitable additive depending on the purpose. The type, number, combination, addition amount, etc. of additives can be appropriately set according to the purpose.

E. Adhesive layer

As described above, the surface resistance of the pressure-sensitive adhesive layer 30 is 1.0×10 ⁹ Ω/□ or less, preferably 5.0×10 ⁸ Ω/□ or less, and more preferably 1.0×10 ⁸ Ω/□ or less. , more preferably 7.0×10 ⁷ Ω/□ or less, and particularly preferably 1.0×10 ⁷ Ω/□ or less. The lower limit of the surface resistance value may be, for example, 5.0×10 ⁵ Ω/□ or less. As described above, according to the embodiment of the present invention, it is possible to realize a pressure-sensitive adhesive layer having a small surface resistance value in spite of the small content of the antistatic agent.

The adhesive force of the pressure-sensitive adhesive layer to glass is preferably 1.0 N/25 mm or more, more preferably 1.5 N/25 mm or more, still more preferably 2.0 N/25 mm or more. If the adhesive force is within this range, the adhesion to the image display panel is excellent, and the reworkability is excellent. The upper limit of adhesive force may be, for example, 6.0 N/25 mm.

The thickness of the pressure-sensitive adhesive layer is preferably 2 μm to 55 μm, more preferably 2 μm to 30 μm, still more preferably 5 μm to 25 μm, and particularly preferably 10 μm to 20 μm.

As described above, the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer contains a base polymer and an antistatic agent. As described above, the base polymer has a glass transition temperature (Tg) of -50°C or lower, preferably -52°C or lower, and more preferably -55°C or lower. The lower limit of Tg of the base polymer may be, for example, -75°C. As described above, the dielectric constant of the base polymer at 100 kHz is 5.0 or more, preferably 5.5 or more, more preferably 6.0 or more, still more preferably 6.5 or more, and particularly preferably 7.0 or more. The upper limit of the permittivity of the base polymer may be, for example, 10.0. By using such a base polymer, it is possible to realize a pressure-sensitive adhesive layer having a small surface resistance value in spite of the small content of the antistatic agent. In addition, the Tg of the base polymer can be calculated as the Tg of the polymer converted from the Tg of each monomer component using a polymerization ratio.

Examples of the base polymer include (meth)acrylic polymers, urethane polymers, silicone polymers, and rubber polymers. Preferably, it is a (meth)acrylic polymer. In this specification, a (meth)acrylic polymer as a base polymer is sometimes referred to as a (meth)acrylic base polymer.

The (meth)acrylic base polymer preferably contains an alkoxy group-containing monomer as a monomer component. Examples of the alkoxy group-containing monomer include monomers represented by the following formula:

In formula, R ^<1> is an alkyl group, for example, a methyl group or an ethyl group, and n is an integer of 1-15. As is clear from the above formula, the alkoxy group is preferably linear. If it is a linear alkoxy group, the Tg of the (meth)acrylic base polymer obtained can be made into the said desired range, and the dielectric constant of the said base polymer can be made into the said desired range. A base polymer containing a monomer having a ring structure may have excessively high Tg and/or excessively low dielectric constant. Specific examples of the alkoxy group-containing monomer include methoxyethyl (meth)acrylate, ethoxyethoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, and methoxypolyethylene glycol (meth)acrylate. can These may be used independently or may be used in combination of 2 or more types. By using an alkoxy group-containing monomer as a monomer component, a base polymer having a desired Tg and dielectric constant can be obtained. As a result, a pressure-sensitive adhesive layer having a small surface resistance value can be realized despite the low content of the antistatic agent. The content of the alkoxy group-containing monomer in the base polymer is preferably 30 parts by weight to 99 parts by weight with respect to 100 parts by weight of all monomer components. The content of the alkoxy group-containing monomer may be, for example, 30 parts by weight to 60 parts by weight, further, for example, 30 parts by weight to 50 parts by weight, or, for example, 50 parts by weight to 99 parts by weight, and For example, 60 weight part - 99 weight part may be sufficient.

The (meth)acrylic base polymer preferably contains a hydroxyl group-containing monomer as a monomer component. Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate. )Acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, (4-hydroxymethylcyclohexyl)-methylacrylic rates can be cited. From the viewpoint of improving the durability of the pressure-sensitive adhesive layer, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred, and 4-hydroxybutyl (meth)acrylate is more preferred. The content of the hydroxyl group-containing monomer in the base polymer is preferably 1 part by weight to 5 parts by weight, more preferably 1 part by weight to 3 parts by weight, based on 100 parts by weight of all monomer components.

The (meth)acrylic base polymer may also contain an alkyl (meth)acrylate as a monomer component. Examples of the alkyl (meth)acrylate include straight-chain or branched-chain alkyl groups having 1 to 18 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, an amyl group, a hexyl group, a cyclohexyl group, a heptyl group, a 2-ethylhexyl group, an isooctyl group, a nonyl group, and A sil group, an isodecyl group, a dodecyl group, an isomyristyl group, a lauryl group, a tridecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, etc. are mentioned. Alkyl (meth)acrylates may be used alone or in combination. The average carbon number of the alkyl group is preferably 3 to 8, more preferably 3 to 6. The content of the alkyl (meth)acrylate in the base polymer can be arbitrarily set as the remainder of the monomer components other than the alkyl (meth)acrylate.

The (meth)acrylic base polymer may further contain other monomer components (copolymerization monomers) as needed. Representative examples of the copolymerization monomer include aromatic hydrocarbon group-containing monomers (e.g., phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, benzyl (meth) acrylate), carboxyl group-containing monomers (e.g., (meth)acrylate, ) acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid), amino group-containing monomers (e.g., N,N-dimethylaminoethyl (meth)acrylic acid) rate), amide group-containing monomers (eg, (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide), nitrile group-containing monomers (eg, , (meth)acrylonitrile), polyfunctional monomers (eg, hexanedioldi(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate), an epoxy group-containing monomer (eg, glycidyl (meth)acrylate), and a heterocycle-containing monomer (eg, acryloylmorpholine). The type, number, combination, and blending amount (content) of the copolymerization monomers can be appropriately set depending on the purpose.

The weight average molecular weight Mw of the (meth)acrylic base polymer is preferably 1 million to 3 million, more preferably 2 million to 3 million, still more preferably 2 million to 2.8 million. When the weight average molecular weight Mw is less than 1,000,000, suppression of cracks may become insufficient. When the weight average molecular weight Mw exceeds 3,000,000, a rise in viscosity and/or gelation during polymer polymerization may occur.

As an antistatic agent, inorganic cation salt and organic cation salt are mentioned typically.

The inorganic cation salt is, specifically, an inorganic cation-anion salt. As a cation which comprises the cation part of an inorganic cation salt, alkali metal ion is mentioned typically. As a specific example, lithium ion, sodium ion, and potassium ion are mentioned. preferably lithium ion. Accordingly, preferred inorganic cation salts are lithium salts.

Examples of the anion constituting the anionic portion of the inorganic cation salt include Cl ^- , Br ^- , I ^- , AlCl ₄ ^- , Al ₂ Cl ₇ ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , NO ₃ ^- , CH ₃ COO ^- , CF ₃ COO ^- , CH ₃ SO ₃ ^- , CF ₃ SO ₃ ^- , (CF ₃ SO ₂ ) ₃ C ^- , AsF ₆ ^- , SbF ₆ - , NbF ₆ ^{- ,} TaF ₆ ^- , (CN) ₂ N ^- , C ₄ F ₉ SO ₃ ^- , C ₃ F ₇ COO ^- , (CF ₃ SO ₂ )(CF ₃ CO)N ^- , ^- O ₃ S(CF ₂ ) ₃ SO ₃ ^- and the following general formula (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 are integers from 1 to 10),

An anion represented by Fluorine-containing anions are preferred, and fluorine-containing imide anions are more preferred.

Examples of the fluorine-containing imide anion include imide anions having a perfluoroalkyl group. As specific examples, the above (CF ₃ SO ₂ )(CF ₃ CO)N ^- and general formulas (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 are integers from 1 to 10),

An anion represented by Preferably, it is a (perfluoroalkylsulfonyl)imide represented by general formula (1) such as (CF ₃ SO ₂ ) ₂ N ^- , (C ₂ F ₅ SO ₂ ) ₂ N ^- , and more preferably is a bis(trifluoromethanesulfonyl)imide represented by (CF ₃ SO ₂ ) ₂ N ^- . Therefore, a preferable inorganic cation salt that can be used in the embodiment of the present invention is lithium bis(trifluoromethanesulfonyl)imide.

The organic cation salt is, specifically, an organic cation-anion salt. As a cation constituting the cation portion of the organic cation salt, typically, organic onium in which an onium ion is formed by substitution with an organic group is exemplified. Examples of the onium in the organic onium include nitrogen-containing onium, sulfur-containing onium, and phosphorus-containing onium. Preferably, they are nitrogen-containing onium and sulfur-containing onium. As the nitrogen-containing onium, ammonium cation, piperidinium cation, pyrrolidinium cation, pyridinium cation, cation having a pyrroline skeleton, cation having a pyrrole skeleton, imidazolium cation, tetrahydropyrimidinium cation, dihydropyridinium A midinium cation, a pyrazolium cation, and a pyrazolinium cation are mentioned. Examples of the sulfur-containing onium include sulfonium cations. As phosphorus containing onium, a phosphonium cation is mentioned, for example. As an organic group in organic onium, an alkyl group, an alkoxyl group, and an alkenyl group are mentioned, for example. Specific examples of preferable organic oniums include tetraalkylammonium cations (for example, tributylmethylammonium cations), alkylpiperidinium cations, and alkylpyrrolidinium cations. The anion constituting the anion portion of the organic cation salt is as described for the anion constituting the anion portion of the inorganic cation. Preferred organic cationic salts that can be used in the embodiment of the present invention are 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide and trimethylbutylammonium bis(trifluoromethanesulfonyl)imide. am.

You may use it combining inorganic cation salt and organic cation salt.

The content of the antistatic agent in the pressure-sensitive adhesive composition is less than 10 parts by weight, preferably 7 parts by weight or less, more preferably 5 parts by weight or less, and still more preferably 5 parts by weight or less with respect to 100 parts by weight of the base polymer. It is preferably 3 parts by weight or less. According to the embodiment of the present invention, it is possible to realize a pressure-sensitive adhesive layer having a small surface resistance value in spite of such a small content of the antistatic agent. The lower limit of the content of the antistatic agent may be, for example, 0.5 parts by weight. When the content of the antistatic agent is too small, a desired surface resistance value may not be obtained.

The pressure-sensitive adhesive composition typically contains a silane coupling agent, a crosslinking agent, and/or an antioxidant. As a silane coupling agent, a functional group containing silane coupling agent is mentioned typically. Examples of the functional group include an epoxy group, a mercapto group, an amino group, an isocyanate group, an isocyanurate group, a vinyl group, a styryl group, an acetoacetyl group, a ureido group, a thiourea group, a (meth)acrylic group, a heterocyclic group, and an acid anhydride. groups and combinations thereof. The functional group-containing silane coupling agent can be used alone or in combination. As a crosslinking agent, an isocyanate type crosslinking agent and a peroxide type crosslinking agent are mentioned. A crosslinking agent may also be used alone or in combination. The following advantages can be obtained by containing a silane coupling agent. Since a pressure-sensitive adhesive composition using a base polymer containing an alkoxy group-containing monomer has high polarity, adhesion to non-polar adherends may be insufficient. By containing a silane coupling agent, sufficient adhesive force can be obtained with respect to various adherends, and peeling can be suppressed. In addition, the following advantages can be obtained by containing an antioxidant. The base polymer containing the alkoxy group-containing monomer has a low Tg and becomes flexible. By containing an antioxidant, shrinkage due to oxidative deterioration from the end face of the polarizing plate and the end face of the pressure-sensitive adhesive layer can be suppressed.

The adhesive composition may contain additives. Specific examples of additives include powders such as colorants and pigments, dyes, surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, softeners, anti-aging agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, inorganic or organic fillers, Metal powder, granular form, and thin material are mentioned. Further, within a controllable range, a redox system in which a reducing agent is added may be employed. The type, number, combination, content, etc. of additives can be appropriately set according to the purpose.

F. Image display device

The polarizing plate according to the above items A to E can be applied to an image display device. Accordingly, an embodiment of the present invention includes an image display device using such a polarizing plate. Representative examples of the image display device include a liquid crystal display device and an electroluminescence (EL) display device (for example, an organic EL display device and an inorganic EL display device). In one embodiment, the image display device is a narrow frame (preferably, bezel-less) image display device or an in-cell type image display device. In such an image display device, the effect according to the embodiment of the present invention is remarkable.

Example

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

(1) Thickness

The thickness of 10 μm or less was measured using an interference film thickness meter (manufactured by Otsuka Electronics, product name “MCPD-3000”). The thickness exceeding 10 μm was measured using a digital micrometer (manufactured by Anritz Corporation, product name “KC-351C”).

(2) Surface resistance value

The resistance value of the surface of the pressure-sensitive adhesive layer of the polarizing plate (polarizing plate having a pressure-sensitive adhesive layer) obtained in Examples and Comparative Examples was measured using MCP-HT450 manufactured by Mitsubishi Chemical Corporation, and used as the initial resistance value. Further, after subjecting the polarizing plate having an adhesive layer to a reliability test under two different conditions (500 hours in an environment of 85°C and 500 hours in an environment of 60°C/95% RH), the resistance value was measured in the same manner as above. . The resistance value increase rate was calculated by the following formula.

Resistance value increase rate (%) = {(resistance value after reliability test - initial resistance value)/initial resistance value} × 100

Moreover, it was evaluated according to the following criteria.

○: Resistance value increase rate is less than 50%

△: Resistance value increase rate is 50% or more and less than 1000%

×: resistance value increase rate is 1000% or more

(3) ESD test

The polarizing plate (polarizing plate having an adhesive layer) obtained in Examples and Comparative Examples was cut out to 70 mm × 150 mm, and bonded to the liquid crystal panel through the adhesive layer. Subsequently, silver paste was applied to the side surface of the polarizing plate with the pressure-sensitive adhesive layer to cover the entire thickness direction of the side surface of the polarizing plate with the pressure-sensitive adhesive layer, and connected to a ground electrode from the outside. Subsequently, a total of 10 shots were fired at intervals of 1 second on the surface of the polarizing plate having the pressure-sensitive adhesive layer, using an ESD (ESD-8012A, manufactured by SANKI) as an electrostatic generator (applied voltage of 15 kV), drawing a circle in the plane of the polarizing plate ( application), causing disorientation of the liquid crystal of the liquid crystal panel. The time until the part whitened by electricity disappears was measured and evaluated according to the following criteria.

○: The white point disappeared within 5 seconds

△: The white spot disappeared within 10 seconds

×: 10 seconds or more left

(4) Delay bubble

A through hole having a diameter of 3.9 mm was formed using an end mill at a corner of the polarizing plate obtained in Examples and Comparative Examples. This polarizing plate was bonded to the glass plate via the pressure-sensitive adhesive layer to obtain a laminate A of polarizing plate/glass plate. On the other hand, a normal optical adhesive sheet was bonded to a cover glass (manufactured by Matsunami Glass Co., Ltd., thickness: 0.8 mm) by a roll laminator to obtain a laminate B of cover glass/optical adhesive. While the polarizing plate of layered product A and the optical adhesive of layered body B were made to face, laminated body A and layered body B were adhere|attached using a vacuum laminator, and the through-hole was filled with the optical adhesive. In this way, an image display device compatible product was produced. The resulting image display device-compatible product was subjected to a heating test (85° C., 24 h) after an autoclave treatment, and the bubble state after the test was visually observed or observed with an optical microscope, and evaluated according to the following criteria.

○: Air bubbles were not confirmed in the charging part.

x: Air bubbles were confirmed in the charging part.

(5) color loss

From the polarizing plates obtained in Examples and Comparative Examples, test pieces (50 mm × 50 mm) having two sides facing each other in the direction of the absorption axis and in the direction orthogonal to the direction of the absorption axis were cut out. A test piece is bonded to a glass plate through an adhesive layer, left in an oven at 65° C. and 90% RH for 120 hours to be humidified, and a polarizing plate after humidification (substantially, The color loss state of the end portion of the polarizer) was examined under a microscope. Specifically, the size of color omission from the end portion of the polarizer (amount of color omission: µm) was measured. Using an MX61L manufactured by Olympus as a microscope, the color loss amount of the corner portion was measured from an image taken at a magnification of 10 times.

(6) Appearance

After subjecting the polarizing plate (cut to a size of 50 mm × 50 mm) obtained in Examples and Comparative Examples to a reliability test (72 hours in an environment of 65 ° C. 90% RH), appearance (swelling of the protective layer, suppression of iodine permeation) The overall appearance of the polarizing plate including the state of the layer, etc.) was visually observed and evaluated according to the following criteria.

○: Expansion, peeling, cracks, and foreign matter were not confirmed.

△: Swelling, peeling, cracks, or foreign matter were observed in several places.

×: A large number of swelling, peeling, cracks, or foreign materials were confirmed throughout.

(7) Cracks in the molded part

A through hole having a diameter of 3.9 mm was formed using an end mill at a corner of the polarizing plate obtained in Examples and Comparative Examples. A polarizing plate with a through hole was bonded to a glass plate through an adhesive layer to obtain a test sample. This test sample was subjected to a heat shock test in which 300 cycles of holding at 85°C for 30 minutes and then holding at -40°C for 30 minutes were repeated, and the appearance of the through hole portion after the test was visually observed, and the following criteria were followed. evaluated as In addition, in any Example and Comparative Example, lack of glue (a phenomenon in which the end portion of the pressure-sensitive adhesive layer is missing) did not occur.

○: Cracks were not confirmed

×: crack was confirmed

[Production Example 1: Preparation of (meth)acrylic base polymer A1]

39 parts of butyl acrylate (BA), 60 parts of methoxyethyl acrylate (MEA), and 4-hydroxybutyl acrylate (4HBA) A monomer mixture containing 1 part was charged. Further, to 100 parts of this monomer mixture, 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator was introduced together with 100 parts of ethyl acetate, and nitrogen gas was introduced with gentle stirring to replace the flask with nitrogen. A solution of (meth)acrylic base polymer A1 was prepared by carrying out a polymerization reaction for 8 hours while maintaining the temperature of the liquid inside at around 55°C. Table 1 shows the Tg and dielectric constant of the (meth)acrylic base polymer A1. In addition, the permittivity was measured by a conventional method. Tg calculated the value converted using the polymerization ratio from Tg of each monomer.

[Production Example 2: Preparation of (meth)acrylic base polymer A2]

A solution of (meth)acrylic base polymer A2 was prepared in the same manner as in Production Example 1 except that 60 parts of ethoxyethoxyethyl acrylate (EEEA) was used instead of 60 parts of MEA. Table 1 shows the Tg and dielectric constant of the (meth)acrylic base polymer A2.

[Production Example 3: Preparation of (meth)acrylic base polymer A3]

A solution of (meth)acrylic base polymer A3 was prepared in the same manner as in Production Example 1 except that 60 parts of methoxytriethylene glycol acrylate (MTGA) was used instead of 60 parts of MEA. Table 1 shows the Tg and dielectric constant of the (meth)acrylic base polymer A3.

[Production Example 4: Preparation of (meth)acrylic base polymer A4]

A solution of (meth)acrylic base polymer A4 was prepared in the same manner as in Production Example 1 except that a monomer mixture containing 99 parts of MTGA and 1 part of 4HBA was used. Table 1 shows the Tg and dielectric constant of the (meth)acrylic base polymer A4.

[Production Example 5: Preparation of (meth)acrylic base polymer A5]

A solution of (meth)acrylic base polymer A5 was prepared in the same manner as in Production Example 1 except that a monomer mixture containing 49 parts of BA, 50 parts of MTGA, and 1 part of 4HBA was used. Table 1 shows the Tg and dielectric constant of the (meth)acrylic base polymer A5.

[Production Example 6: Preparation of (meth)acrylic base polymer A6]

A solution of (meth)acrylic base polymer A6 was prepared in the same manner as in Production Example 1 except that a monomer mixture containing 69 parts of BA, 30 parts of MTGA, and 1 part of 4HBA was used. Table 1 shows the Tg and dielectric constant of the (meth)acrylic base polymer A6.

[Production Example 7: Preparation of (meth)acrylic base polymer A7]

A solution of (meth)acrylic base polymer A7 was prepared in the same manner as in Production Example 5, except that 50 parts of methoxypolyethylene glycol acrylate (MPEA) was used instead of 50 parts of MTGA. Table 1 shows the Tg and dielectric constant of the (meth)acrylic base polymer A7.

[Production Example 8: Preparation of (meth)acrylic base polymer A8]

A solution of (meth)acrylic base polymer A8 was prepared in the same manner as in Production Example 1 except that a monomer mixture containing 79 parts of BA, 20 parts of MEA, and 1 part of 4HBA was used. Table 1 shows the Tg and dielectric constant of the (meth)acrylic base polymer A8.

[Production Example 9: Preparation of (meth)acrylic base polymer A9]

A solution of (meth)acrylic base polymer A9 was prepared in the same manner as in Production Example 5 except that 50 parts of phenoxyethyl acrylate (PEA) was used instead of 50 parts of MTGA. Table 1 shows the Tg and dielectric constant of the (meth)acrylic base polymer A9.

[Production Example 10: Preparation of (meth)acrylic base polymer A10]

A solution of (meth)acrylic base polymer A10 was prepared in the same manner as in Production Example 5, except that 50 parts of tetrahydrofurfuryl acrylate was used instead of 50 parts of MTGA. Table 1 shows the Tg and dielectric constant of the (meth)acrylic base polymer A10.

[Production Example 11: Preparation of (meth)acrylic base polymer A11]

A solution of (meth)acrylic base polymer A11 in the same manner as in Production Example 5 except that 50 parts of (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methylacrylate was used instead of 50 parts of MTGA. prepared Table 1 shows the Tg and dielectric constant of the (meth)acrylic base polymer A11.

[Production Example 12: Preparation of (meth)acrylic base polymer A12]

A solution of (meth)acrylic base polymer A12 was prepared in the same manner as in Production Example 5, except that 50 parts of (3-ethyloxetan-3-yl)methylacrylate was used instead of 50 parts of MTGA. Table 1 shows the Tg and dielectric constant of the (meth)acrylic base polymer A12.

[Production Example 13: Preparation of (meth)acrylic base polymer A13]

A solution of (meth)acrylic base polymer A13 was prepared in the same manner as in Production Example 5, except that 50 parts of cyclic trimethylolpropane formal acrylate was used instead of 50 parts of MTGA. Table 1 shows the Tg and dielectric constant of the (meth)acrylic base polymer A13.

[Production Example 14: Preparation of (meth)acrylic base polymer A14]

In the same manner as in Production Example 1 except that a monomer mixture containing 80.3 parts of BA, 0.2 parts of acrylic acid (AA), 16 parts of PEA, 3 parts of N-vinylpyrrolidone (NVP), and 0.5 part of 4HBA was used. , A solution of (meth)acrylic base polymer A14 was prepared. Table 1 shows the Tg and dielectric constant of the (meth)acrylic base polymer A14.

[Production Example 15: Preparation of (meth)acrylic base polymer A15]

A solution of (meth)acrylic base polymer A15 was prepared in the same manner as in Production Example 1 except that a monomer mixture containing 99 parts of BA and 1 part of 4HBA was used. Table 1 shows the Tg and dielectric constant of the (meth)acrylic base polymer A15.

[Production Example 16: Production of Polarizing Plate P1]

1. Fabrication of polarizer

As the thermoplastic resin substrate, an amorphous isophthalic copolymerized polyethylene terephthalate film (thickness: 100 μm) having a long shape, water absorption of 0.75%, and Tg of about 75° C. was used. Corona treatment was performed on one side of the resin substrate.

Polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Kosei Chemical Industry Co., Ltd., trade name "Gosefimer Z410") were mixed in a ratio of 9:1 to 100 parts by weight of a PVA-based resin, iodinated What added 13 parts by weight of potassium was dissolved in water to prepare a PVA aqueous solution (coating liquid).

The PVA-based resin layer having a thickness of 13 μm was formed by applying the PVA aqueous solution to the corona-treated surface of the resin substrate and drying it at 60° C., thereby producing a laminate.

The obtained layered product was uniaxially stretched at the free end by 2.4 times in the longitudinal direction (long side direction) between rolls having different circumferential speeds in a 130°C oven (air assisted stretching treatment).

Next, the laminate was immersed in an insolubilization bath (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 40°C for 30 seconds (insolubilization treatment).

Next, in a dyeing bath (100 parts by weight of water, an iodine aqueous solution obtained by blending iodine and potassium iodide at a weight ratio of 1:7) at a solution temperature of 30 ° C., the single transmittance (Ts) of the polarizer finally obtained is a predetermined value. It was immersed for 60 seconds while adjusting the concentration as much as possible (dyeing treatment).

Next, it was immersed in a crosslinking bath (a boric acid aqueous solution obtained by blending 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with respect to 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (crosslinking treatment).

Thereafter, the laminate was immersed in an aqueous solution of boric acid at a liquid temperature of 70°C (boric acid concentration: 4.0% by weight, potassium iodide concentration: 5% by weight), while the total draw ratio was 5.5 in the longitudinal direction (long side direction) between rolls having different circumferential speeds. Uniaxial stretching was performed so as to double (underwater stretching treatment).

Thereafter, the laminate was immersed in a washing bath (aqueous solution obtained by blending 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 20°C (washing treatment).

Thereafter, while drying in an oven maintained at 90°C, it was brought into contact with a heating roll made of SUS whose surface temperature was maintained at 75°C for about 2 seconds (dry shrinkage treatment). The shrinkage rate in the width direction of the layered product by the drying shrinkage treatment was 5.2%.

In this way, a polarizer having a thickness of 5 μm was formed on the resin substrate.

2. Fabrication of polarizer

An HC-TAC film was bonded to the surface of the polarizer obtained above (surface on the opposite side to the resin substrate) as a protective layer through an ultraviolet curable adhesive. Specifically, the coating was applied so that the total thickness of the curable adhesive was 1.0 µm, and bonding was performed using a roll machine. Thereafter, UV rays were irradiated from the protective layer side to cure the adhesive. In addition, the HC-TAC film is a film in which a hard coat (HC) layer (thickness of 7 μm) is formed on a triacetyl cellulose (TAC) film (thickness of 25 μm), and the TAC film is bonded so as to be on the polarizer side. Next, the resin substrate was peeled off, and an iodine permeation inhibiting layer (thickness: 0.3 µm) was formed on the peeled surface. In addition, the iodine permeation suppression layer was formed as follows.

97.0 parts of methyl methacrylate (MMA, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "methyl methacrylate monomer"), 3.0 parts of copolymerization monomer represented by the general formula (1e), polymerization initiator (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., 0.2 part of brand name "2,2'-azobis (isobutyronitrile)") was dissolved in 200 parts of toluene. Then, a polymerization reaction was performed for 5.5 hours while heating at 70°C in a nitrogen atmosphere to obtain a boron-containing acrylic resin solution (solid content concentration: 33%). Tg of the obtained boron-containing acrylic polymer was 110°C and Mw was 80000. 20 parts of this boron-containing acrylic polymer was dissolved in 80 parts of methyl ethyl ketone to obtain a resin solution (20%). This resin solution was applied to the peeling surface of the resin substrate using a wire bar, and the coated film was dried at 60° C. for 5 minutes to form an iodine permeation suppression layer composed of a solidified product of the coated film of the organic solvent solution of the resin.

In this way, a polarizing plate P1 having a configuration of protective layer (HC layer/TAC film)/adhesive layer/polarizer/iodine permeation suppression layer was obtained.

[Production Example 17: Production of Polarizing Plate P2]

A polyvinyl alcohol film having a thickness of 30 μm was stretched up to 3 times between rolls at different speed ratios, dyeing for 1 minute in a 0.3% concentration iodine solution at 30°C. Then, the total draw ratio was extended|stretched to 6 times, immersing for 0.5 minute in the aqueous solution containing 60 degreeC, 4% concentration boric acid, and 10% concentration potassium iodide. Next, after washing by immersing for 10 seconds in an aqueous solution containing potassium iodide at 30°C and a concentration of 1.5%, drying was performed at 50°C for 4 minutes to obtain a polarizer having a thickness of 12 μm. An HC-TAC film was bonded to one side of the polarizer in the same manner as in Production Example 15. Furthermore, an acrylic film (thickness: 20 μm) having a lactone ring structure was bonded to the other surface of the polarizer via an ultraviolet curable adhesive (thickness: 1.0 μm). Further, an iodine permeation suppression layer (thickness: 0.3 µm) was formed on the surface of the acrylic film in the same manner as in Production Example 16. In this way, polarizing plate P2 having a configuration of protective layer (HC layer/TAC film)/adhesive layer/polarizer/adhesive layer/protective layer (acrylic film)/iodine permeation suppression layer was obtained.

[Production Example 18: Production of Polarizing Plate P3]

A polarizing plate P3 was obtained in the same manner as in Production Example 17 except that a cyclic olefin resin (COP) film (thickness: 13 µm) was used instead of the acrylic film.

[Example 1]

1. Preparation of pressure-sensitive adhesive composition

Based on 100 parts of the solid content of the solution of the (meth)acrylic base polymer A1 obtained in Production Example 1, 3 parts of an antistatic agent (trade name: LiTFSi30EA, manufactured by Mitsubishi Materials Co., Ltd.), benzoyl peroxide as a crosslinking agent (trade name: Nyper BMT 40SV, Nippon Yushi Co., Ltd.) 0.3 part, isocyanate-based crosslinking agent (trade name: Takenate D110N, manufactured by Mitsui Chemicals Co., Ltd.) 0.2 part, rework improver (trade name: Cyrill SAT10, manufactured by Kaneka Co., Ltd.) 0.03 part, antioxidant (trade name) : 0.3 part of Irganox 1010, hindered phenolic, manufactured by BASF Japan Co., Ltd., and 0.2 part of silane coupling agent (trade name: A-100, manufactured by Soken Chemical Co., Ltd., silane coupling agent containing an acetoacetyl group) are blended to form a solution of an acrylic pressure-sensitive adhesive composition prepared

2. Fabrication of polarizing plate with pressure-sensitive adhesive layer

The solution of the acrylic pressure-sensitive adhesive composition obtained above was applied to one side of a polyethylene terephthalate film (manufactured by Mitsubishi Chemical Polyester Film, trade name "MRF38", separator film) treated with a silicone-based release agent, and the thickness of the pressure-sensitive adhesive layer after drying was 15 μm. It was applied as much as possible, and dried at 155°C for 1 minute to form an adhesive layer on the surface of the separator film. Subsequently, the pressure-sensitive adhesive layer formed on the separator film was transferred to the surface of the iodine permeation suppression layer of the polarizing plate P1 prepared in Production Example 16, thereby producing a polarizing plate having a pressure-sensitive adhesive layer. The polarizing plate having the obtained pressure-sensitive adhesive layer was used for evaluation of the above (2) to (7). The results are shown in Table 1.

[Examples 2 to 24 and Comparative Examples 1 to 12]

A polarizing plate having an adhesive layer was produced with a combination of the polarizing plate and the pressure-sensitive adhesive layer shown in Table 1. The results are shown in Table 1. In addition, the abbreviation of the antistatic agent in Table 1 is as follows.

LiTFSI: lithium bis(trifluoromethanesulfonyl)imide

EMI-FSI: 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide

TBMA-TFSI: tributylmethylammonium bis(trifluoromethanesulfonyl)imide

[evaluation]

As is clear from Table 1, the polarizing plate of the examples of the present invention shows good results in the ESD test and maintains a low surface resistance value even after the reliability test. In addition, in the polarizing plate of the embodiment of the present invention, delay bubbles, color loss during humidification, poor appearance after reliability test, and cracks during release processing are all well suppressed.

The polarizing plate of the present invention is suitably used for image display devices such as liquid crystal display devices, organic EL display devices, and inorganic EL display devices.

11: polarizer
12: protective layer
30: adhesive layer
40: iodine permeation inhibitory layer
100: polarizer

Claims (13)

A polarizer, a protective layer provided on one side of the polarizer, an iodine permeation inhibiting layer provided on the other side of the polarizer, and an adhesive layer provided on the opposite side of the iodine permeation inhibiting layer to the polarizer,
The iodine permeation inhibiting layer is a solidified material or a thermoset material of a coating film of an organic solvent solution of a resin,
The pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer contains a base polymer and an antistatic agent,
The base polymer has a glass transition temperature of -50°C or less, and a dielectric constant of 5.0 or more at 100 kHz,
A polarizing plate having a surface resistance value of the pressure-sensitive adhesive layer of 1.0×10 ⁹ Ω/□ or less. The polarizing plate according to claim 1, wherein the base polymer contains an alkoxy group-containing monomer as a monomer component. The polarizing plate according to claim 2, wherein the base polymer contains 20 parts by weight to 99 parts by weight of the alkoxy group-containing monomer based on 100 parts by weight of all monomer components. The polarizing plate according to claim 3, wherein the alkoxy group-containing monomer is represented by the following formula:

In formula, R ^<1> is an alkyl group, and n is an integer of 1-15. The polarizing plate according to claim 4, wherein the base polymer further contains a hydroxyl group-containing monomer as a monomer component. The polarizing plate according to any one of claims 1 to 5, wherein the content of the antistatic agent in the pressure-sensitive adhesive composition is 10 parts by weight or less with respect to 100 parts by weight of the base polymer. The method according to any one of claims 1 to 6, wherein the antistatic agent is lithium bis(trifluoromethanesulfonyl)imide or 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide. Or a polarizing plate containing tributylmethylammonium bis(trifluoromethanesulfonyl)imide. The polarizing plate according to any one of claims 1 to 7, wherein the pressure-sensitive adhesive composition further contains a silane coupling agent. The polarizing plate according to any one of claims 1 to 8, wherein the pressure-sensitive adhesive composition further contains an antioxidant. The polarizing plate according to any one of claims 1 to 9, wherein the adhesive force of the pressure-sensitive adhesive layer to glass is 1.0 N/25 mm or more. The method according to any one of claims 1 to 10, wherein the resin constituting the iodine permeation inhibiting layer is a (meth)acrylic monomer of more than 50 parts by weight and more than 0 parts by weight and less than 50 parts by weight of formula (1) A polarizing plate comprising a copolymer obtained by polymerizing a monomer mixture containing the monomers represented:

(Wherein, X is selected from the group consisting of a vinyl group, a (meth)acrylic group, a styryl group, a (meth)acrylamide group, a vinylether group, an epoxy group, an oxetane group, a hydroxyl group, an amino group, an aldehyde group, and a carboxyl group represents a functional group containing at least one reactive group, and R ¹ and R ² are each independently a hydrogen atom, an aliphatic hydrocarbon group which may have a substituent, an aryl group which may have a substituent, or a hetero which may have a substituent represents ventilation, and R ¹ and R ² may be connected to each other to form a ring). The polarizing plate according to any one of claims 1 to 11 having a total thickness of 60 µm or less. An image display device provided with the polarizing plate according to any one of claims 1 to 12.

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