CN111837062A - Polarizing plate and image display device using the same - Google Patents

Abstract

The present invention aims to provide a polarizing plate in which deiodination is suppressed even in a high-temperature and high-humidity environment. The polarizing plate is characterized in that a protective film is laminated on one surface of a polarizing film through an adhesive layer, and an adhesive layer is arranged on the other surface of the polarizing film, wherein the polarizing film is a film formed by adsorbing iodine on a hydrophilic polymer film, and the adhesive layer have moisture permeabilities of 100 g/(m.multidot.m.multidot.m.multidot.H. under the conditions of temperature 40 ℃ and relative humidity of 92% R.multidot.H²Day) below.

Description

Polarizing plate and image display device using the same

technical field

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

Background technique

In recent years, the popularity of mobile phones, tablet terminals, and the like has progressed, and liquid crystal display devices and organic EL display devices (OLED) have come to be widely used as image display devices. In addition, along with the reduction in the thickness of the display device, the reduction in thickness of each member such as a polarizing plate to be used is required.

As a polarizing plate, what has a protective film laminated|stacked on both surfaces of a polarizing film is used normally.

With the reduction in thickness of polarizing plates, research into thinning polarizing films and protective films is being conducted, and further, a method of realizing thinning by using a single-sided protective film polarizing plate in which a protective film is laminated only on one side has been proposed.

Along with such thinning, in the conventional polarizing plate including the polarizing film dyed with iodine of a polyvinyl alcohol-based resin, deiodination of the edge of the polarizing film has become a problem in a high temperature and high humidity environment. When iodine is removed from the end portion of the polarizing film to the display region of the display terminal, light leakage occurs, and thus the display quality is remarkably degraded. Recently, there has been a tendency to narrow the frame of the display device and widen the display area, and this problem has become prominent.

In order to solve this problem, Patent Document 1 discloses a method of blending an alkali metal salt with an acrylic pressure-sensitive adhesive. Moreover, in patent document 2, the method of mix|blending the silane compound which does not contain an epoxy group or a primary amino group to an acrylic adhesive is disclosed. However, with the narrowing of the frame of the image display device, further improvement of deiodination is required.

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2012-247574

Patent Document 2: Japanese Patent Laid-Open No. 2015-227937

SUMMARY OF THE INVENTION

The problem to be solved by the invention

An object of the present invention is to provide a polarizing plate in which deiodination is suppressed even in a high-temperature and high-humidity environment.

method used to solve the problem

That is, the present invention provides the following polarizing plates and image display devices.

[1] A polarizing plate in which a protective film is laminated on one surface of the polarizing film via an adhesive layer, and a polarizing plate is provided with an adhesive layer on the other surface,

The polarizing film is a film in which iodine is adsorbed on the hydrophilic polymer film,

The water vapor transmission rate of the pressure-sensitive adhesive layer and the pressure-sensitive adhesive layer under the conditions of a temperature of 40° C. and a relative humidity of 92% RH were both 100 g/(m ² ·day) or less.

[2] The polarizing plate according to [1], wherein the pressure-sensitive adhesive layer is an pressure-sensitive adhesive formed from a rubber-based pressure-sensitive adhesive composition containing polyisobutylene and a hydrogen abstraction type photopolymerization initiator Floor.

[3] The polarizing plate according to [1], wherein the pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer containing a polyolefin-based resin.

[4] The polarizing plate according to [3], wherein the polyolefin-based resin contains an amorphous polypropylene-based resin.

[5] The polarizing plate according to any one of [1] to [4], wherein the polarizing film has a thickness of 15 μm or less.

[6] An image display device comprising the polarizing plate according to any one of [1] to [5].

Invention effect

According to the present invention, it is possible to provide a polarizing plate in which deiodination is suppressed even in a high-temperature and high-humidity environment.

In addition, the present invention can provide an image display device excellent in display quality even in a high-temperature and high-humidity environment by using the polarizing plate.

Detailed ways

Hereinafter, preferred embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

(polarizing film)

The polarizing film is not particularly limited, and various polarizing films can be used. As the polarizing film, for example, a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially methylated polyvinyl alcohol-based film, and an ethylene/vinyl acetate copolymer-based partially saponified film can be uniaxially stretched by adsorbing iodine. Stretched polarizing film. Among them, a polarizing film containing a polyvinyl alcohol-based film and iodine is suitable. The thickness of these polarizing films is not particularly limited, but is generally about 3 to 80 μm.

As the polyvinyl alcohol-based film, a film obtained by saponifying a polyvinyl acetate-based resin can be used. As the polyvinyl acetate-based resin, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, a copolymer of vinyl acetate and another monomer which can be copolymerized can be mentioned. Examples of other monomers that can be copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

The degree of saponification of the polyvinyl alcohol-based resin is usually about 85 to 100 mol %, preferably 98 mol % or more. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal, polyvinyl acetal, or the like modified with aldehydes may be used. In addition, the degree of polymerization of the polyvinyl alcohol-based resin is usually about 1,000 to 10,000, preferably about 1,500 to 5,000.

A film formed from a polyvinyl alcohol-based resin is used as a raw material film of a polarizing film. The method of forming a polyvinyl alcohol-based resin into a film can be formed by a known method. The film thickness of the polyvinyl alcohol-based raw material film is preferably about 5 to 35 μm, and more preferably 5 to 20 μm, considering that the thickness of the obtained polarizing film is 15 μm or less. When the film thickness of a raw material film is 35 micrometers or more, it becomes necessary to raise the draw ratio at the time of manufacturing a polarizing film, and there exists a tendency for the dimensional shrinkage of the polarizing film obtained to become large. On the other hand, when the film thickness of a raw material film is 5 micrometers or less, the workability|operativity at the time of extending|stretching will fall, and there exists a tendency for troubles, such as a cutting|disconnection, to easily generate|occur|produce in manufacture.

The uniaxial stretching of the polyvinyl alcohol-based resin film may be performed before, simultaneously with, or after dyeing with iodine. In the case of performing uniaxial stretching after dyeing, the uniaxial stretching may be performed before or during boric acid treatment. In addition, uniaxial stretching may be performed in these plural stages.

In the case of uniaxial stretching, it may be uniaxially stretched between rolls having different circumferential speeds, or it may be uniaxially stretched using a heated roll. In addition, the uniaxial stretching may be dry stretching in which stretching is performed in the air, or wet stretching in which stretching is performed in a state where the polyvinyl alcohol-based resin film is swollen using a solvent. The draw ratio is usually about 3 to 8 times.

As a method of dyeing the polyvinyl alcohol-based resin film with iodine, for example, a method of immersing the polyvinyl alcohol-based resin film in an aqueous solution containing iodine can be employed. In addition, it is preferable to perform the immersion process in water before a dyeing process of a polyvinyl alcohol-type resin film.

A method of dyeing a polyvinyl alcohol-based resin film by immersing it in an aqueous solution containing iodine and potassium iodide is employed. The content of iodine in the aqueous solution is usually about 0.01 to 1 part by weight per 100 parts by weight of water. In addition, the content of potassium iodide is usually about 0.5 to 20 parts by weight per 100 parts by weight of water. The temperature of the aqueous solution used for dyeing is usually about 20 to 40°C. In addition, the immersion time (dyeing time) in this aqueous solution is usually about 20 to 1800 seconds.

The boric acid treatment after dyeing with iodine can usually be performed by immersing the dyed polyvinyl alcohol-based resin film in an aqueous solution containing boric acid.

The amount of boric acid in the boric acid-containing aqueous solution is usually about 2 to 15 parts by weight per 100 parts by weight of water, preferably 5 to 12 parts by weight. The boric acid-containing aqueous solution preferably contains potassium iodide. The amount of potassium iodide in the boric acid-containing aqueous solution is usually about 0.1 to 15 parts by weight per 100 parts by weight of water, preferably about 5 to 12 parts by weight. The immersion time in the aqueous solution containing boric acid is usually about 60 to 1200 seconds, preferably about 150 to 600 seconds, and more preferably about 200 to 400 seconds. The temperature of the aqueous solution containing boric acid is usually 50°C or higher, preferably 50 to 85°C, and more preferably 60 to 80°C.

The polyvinyl alcohol-based resin film after the boric acid treatment is usually washed with water. The water washing treatment can be performed, for example, by immersing the boric acid-treated polyvinyl alcohol-based resin film in water. The temperature of the water in the water washing treatment is usually about 5 to 40°C. In addition, the immersion time is usually about 1 to 120 seconds.

After washing with water, drying treatment is performed to obtain a polarizing film. The drying process can be performed using a hot air dryer or a far-infrared heater. The temperature of the drying treatment is usually about 30 to 100°C, preferably 50 to 80°C. The drying time is usually about 60 to 600 seconds, preferably 120 to 600 seconds.

The drying process reduces the moisture content of the polarizing film to a practical level. The moisture content is usually 5 to 20% by weight, preferably 8 to 15% by weight. When the moisture content is less than 5% by weight, the flexibility of the polarizing film is lost, and the polarizing film may be damaged or broken after drying. Moreover, when a moisture content exceeds 20 weight%, the thermal stability of a polarizing film may be inferior.

In addition, the stretching, dyeing, boric acid treatment, water washing process, and drying process of the polyvinyl alcohol-based resin film in the manufacturing process of the polarizing film can be performed in accordance with, for example, the method described in JP-A No. 2012-159778. In the method described in this document, a polyvinyl alcohol-based resin layer serving as a polarizer is formed by applying a polyvinyl alcohol-based resin to a base film.

The thickness of the polarizing film is 15 μm or less, preferably 3 to 10 μm.

In addition, the polarizing film can be used as a single-sided protective polarizing plate having a protective film only on one side of the polarizing film.

(protective film)

As a material for forming the protective film provided on one side of the polarizing film, a material excellent in transparency, mechanical strength, thermal stability, water resistance, isotropy, and the like is preferable. For example, polyester-based resins such as polyethylene terephthalate and polyethylene naphthalate, cellulose-based resins such as diacetyl cellulose and triacetyl cellulose, polymethyl methacrylate, etc. Acrylic resin, polystyrene, styrene resin such as acrylonitrile/styrene copolymer (AS resin), polycarbonate resin, and the like.

In addition, examples of the resin forming the protective film include polyethylene, polypropylene, polyolefins having a cyclic or norbornene structure, polyolefin-based resins such as ethylene/propylene copolymers, and vinyl chloride-based resins. , Nylon, aromatic polyamide and other amide resins, imide resins, sulfone resins, polyether sulfone resins, polyether ether ketone resins, polyphenylene sulfide resins, vinyl alcohol resins, vinylidene chloride Vinyl-based resin, vinyl butyral-based resin, arylate-based resin, polyoxymethylene-based resin, epoxy-based resin, or a blend of these resins, and the like. The protective film can also be formed as a cured layer of thermosetting and ultraviolet curing resins such as acrylic, urethane, acrylic urethane, epoxy, and silicone.

The thickness of the protective film can be appropriately determined, but is usually about 1 to 500 μm from the viewpoints of strength, handling properties such as handling properties, and film properties.

The polarizing film and the protective film are usually laminated via a water-based adhesive or the like. Examples of the water-based adhesive include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latex-based adhesives, water-based polyurethanes, and water-based polyesters. In addition to the above, examples of the adhesive between the polarizing film and the protective film include an ultraviolet curable adhesive, an electron beam curable adhesive, and the like. The adhesive for electron beam curable polarizing films shows suitable adhesiveness with respect to the above-mentioned various protective films. The protective film is preferably subjected to saponification treatment, corona treatment, plasma treatment, and the like before being bonded to the polarizing film.

A hard coat layer or antireflection treatment, an antistatic layer or an antiblocking layer, and treatment for diffusion or antiglare can be applied to the surface of the protective film to which the polarizing film is not adhered.

<Adhesive Adhesive Layer>

The polarizing plate of this invention has the layer structure in which the protective film was laminated|stacked on one surface of a polarizing film via an adhesive bond layer, and the adhesive layer was laminated|stacked on the other surface. In this polarizing plate, the moisture permeability of the adhesive layer and the adhesive layer under the conditions of a temperature of 40° C. and a relative humidity of 92% RH were both 100 g/(m ² ·day) or less. The polarizing plate of such a structure becomes a polarizing plate which is difficult to remove iodine from an edge part in a high temperature and high humidity environment. Hereinafter, the pressure-sensitive adhesive layer or the pressure-sensitive adhesive layer may be collectively referred to as "adhesive pressure-sensitive adhesive layer".

The water vapor transmission rate of the pressure-sensitive adhesive layer is 100 g/(m ² ·day) or less, preferably 50 g/(m ² ·day) or less, more preferably 30 g/(m ² ·day) or less, and still more preferably 20g/(m ² ·day) or less. In addition, the lower limit value of the water vapor transmission rate is not particularly limited, but ideally, it is preferable that the water vapor is not permeated at all (ie, 0 g/(m ² ·day)). When the water vapor transmission rate of the adhesive bond layer is in the above range, moisture that permeates the bond adhesive bond layer from the side surface of the polarizing plate and reaches the polarizing film can be suppressed, so that deiodination from the edge of the polarizing plate can be reduced. quantity. The moisture permeability is the water vapor transmission rate (moisture permeability) under the conditions of a temperature of 40° C. and a relative humidity of 92% RH when the thickness of the adhesive layer is 50 μm, and the measurement method can be as described in the Examples. Methods.

<Adhesive layer>

The adhesive bond layer is a layer for bonding the polarizing film and the protective film, and has a moisture permeability of 100 g/(m ² ·day) or less. As an adhesive bond layer, what is necessary is just to make it 100 g/(m ² ·day) or less in the moisture vapor transmission under conditions of a temperature of 40° C. and a relative humidity of 92% RH. The composition of the adhesive forming the adhesive layer is not particularly limited, and a layer containing any appropriate adhesive can be used. Examples of such adhesives include natural rubber adhesives, α-olefin-based adhesives, urethane resin-based adhesives, ethylene-vinyl acetate resin emulsion adhesives, and ethylene-vinyl acetate adhesives. Ester resin based hot melt adhesives, epoxy resin based adhesives, vinyl chloride resin solvent based adhesives, chloroprene rubber based adhesives, cyanoacrylate based adhesives, silicone based adhesives adhesive, styrene-butadiene rubber solvent-based adhesive, nitrile rubber-based adhesive, nitrocellulose-based adhesive, reactive hot-melt adhesive, phenolic resin-based adhesive, modified silicone adhesives, polyester-based hot-melt adhesives, polyamide resin hot-melt adhesives, polyimide-based adhesives, polyurethane resin hot-melt adhesives, polyolefin resin hot-melt adhesives, polyamide resin hot-melt adhesives Vinyl acetate resin solvent-based adhesive, polystyrene resin solvent-based adhesive, polyvinyl alcohol-based adhesive, polyvinylpyrrolidone resin-based adhesive, polyvinyl butyral-based adhesive, polyvinyl Benzimidazole adhesives, polymethacrylate resin solvent-based adhesives, melamine resin-based adhesives, urea-formaldehyde resin-based adhesives, resorcinol-based adhesives, and the like. Such an adhesive can be used individually by 1 type or in mixture of 2 or more types.

As an adhesive, if it is classified by an adhesive form, a thermosetting adhesive, a hot melt adhesive, etc. are mentioned, for example. Only one type of such adhesive may be used, or two or more types may be used.

A thermosetting adhesive is thermally cured by heating and then cured, thereby expressing the adhesive force. As a thermosetting adhesive, an epoxy type thermosetting adhesive, a urethane type thermosetting adhesive, an acrylic thermosetting adhesive etc. are mentioned, for example. The curing temperature of the thermosetting adhesive is, for example, 100 to 200°C.

The hot-melt adhesive is melted or softened by heating, thermally fused to the adherend, and solidified by subsequent cooling, thereby adhering to the adherend. As the hot-melt adhesive, for example, a rubber-based hot-melt adhesive, a polyester-based hot-melt adhesive, a polyolefin-based hot-melt adhesive, an ethylene-vinyl acetate resin-based hot-melt adhesive, Polyamide resin hot melt adhesive, polyurethane resin hot melt adhesive, etc. The softening temperature (ring and ball method) of the hot melt adhesive is, for example, 100 to 200°C. In addition, the melt viscosity of the hot melt adhesive is, for example, 100 to 30000 mPa·s at 180°C.

Although the thickness of an adhesive bond layer is not specifically limited, For example, it is preferable that it is about 0.01-10 micrometers, and it is more preferable that it is about 0.05-8 micrometers.

<Adhesive layer>

The pressure-sensitive adhesive layer is a layer for laminating a polarizing film and a functional layer described later, and has a moisture permeability of 100 g/(m ² ·day) or less. The pressure-sensitive adhesive layer should just have a water vapor transmission rate under the conditions of a temperature of 40° C. and a relative humidity of 92% RH of 100 g/(m ² ·day) or less. The composition of the pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer is not particularly limited, and a layer containing any appropriate pressure-sensitive adhesive can be used. Examples of the adhesive include rubber-based adhesives, polyolefin-based adhesives, acrylic-based adhesives, silicone-based adhesives, urethane-based adhesives, and vinyl alkyl ether-based adhesives. Adhesives, polyvinyl alcohol-based adhesives, polyvinylpyrrolidone-based adhesives, polyacrylamide-based adhesives, cellulose-based adhesives, etc. Among them, rubber is preferred from the viewpoint of moisture permeability adhesive, polyolefin adhesive.

The composition of the rubber-based adhesive is not particularly limited as long as it is an adhesive containing a rubber-based polymer.

The rubber-based polymer used in the present invention is a polymer that exhibits rubber elasticity in a temperature region around room temperature. Specifically, a styrene-based thermoplastic elastomer, an isobutylene-based polymer, etc. are mentioned. In the present invention, polyisobutylene (PIB), which is a homopolymer of isobutylene, is preferably used from the viewpoint of weather resistance. This is because polyisobutylene is excellent in light resistance because it does not contain a double bond in the main chain.

As the polyisobutylene, for example, commercially available products such as OPPANOL manufactured by BASF can be used.

The weight average molecular weight (Mw) of the polyisobutylene is preferably 100,000 or more, more preferably 300,000 or more, still more preferably 600,000 or more, and particularly preferably 700,000 or more. Moreover, although the upper limit of a weight average molecular weight is not specifically limited, 5 million or less is preferable, 3 million or less is more preferable, and 2 million or less is still more preferable. By setting the weight-average molecular weight of the polyisobutylene to be 100,000 or more, a rubber-based adhesive with more excellent durability during high-temperature storage can be obtained.

The content of the polyisobutylene is not particularly limited, but is preferably 50% by weight or more, more preferably 60% by weight or more, still more preferably 70% by weight or more, and still more preferably 50% by weight or more in the total solid content of the rubber-based adhesive. 80% by weight or more, more preferably 85% by weight or more, and particularly preferably 90% by weight or more. The upper limit of the content of polyisobutylene is not particularly limited, but is preferably 99% by weight or less, and more preferably 98% by weight or less. By including polyisobutylene in the above-mentioned range, it is excellent in low moisture permeability, which is preferable.

In addition, the rubber-based adhesive used in the present invention may contain polymers, elastomers, and the like other than the above-mentioned polyisobutylene. Specifically, copolymers of isobutylene and n-butylene, copolymers of isobutylene and isoprene (for example, ordinary butyl rubber, chlorinated butyl rubber, bromobutyl rubber, partially cross-linked butyl rubber, etc.) isobutylene-based polymers such as butyl rubbers), their sulfides or modified products (for example, polymers modified with functional groups such as hydroxyl, carboxyl, amino, and epoxy groups); styrene-ethylene-butylene- Styrene block copolymer (SEBS), styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene-styrene block copolymer (SBS), styrene-ethylene- Propylene-styrene block copolymer (hydrogenated product of SEPS, SIS), styrene-ethylene-propylene block copolymer (SEP, hydrogenated product of styrene-isoprene block copolymer), styrene-isobutylene - Styrenic thermoplastic elastomers such as styrene block copolymers (SIBS) and styrene-butadiene rubber (SBR); butyl rubber (IIR), butadiene rubber (BR) ), acrylonitrile-butadiene rubber (NBR), EPR (binary ethylene-propylene rubber), EPT (tertiary ethylene-propylene rubber), acrylic rubber, urethane rubber, polyurethane thermoplastic elastomer ; Polyester thermoplastic elastomer; Polypropylene and EPT (ternary ethylene-propylene rubber) polymer blends and other blends thermoplastic elastomers. Although these can be added in the range which does not impair the effect of this invention, it is preferable that it is about 10 weight part or less with respect to 100 weight part of said polyisobutylene, and it is preferable not to contain from a durability viewpoint.

In addition, it is particularly preferable that the rubber-based adhesive used in the present invention contains the above-described polyisobutylene and a hydrogen abstraction type photopolymerization initiator.

The so-called hydrogen abstraction type photopolymerization initiator is an initiator that, by irradiation with active energy rays, can abstract hydrogen from the polyisobutylene without cracking the initiator itself to form reaction sites in the polyisobutylene. By forming this reaction point, the crosslinking reaction of polyisobutylene can be initiated.

As the photopolymerization initiator, in addition to the hydrogen abstraction type photopolymerization initiator used in the present invention, a cleavage type photopolymerization initiator in which the photopolymerization initiator itself is cleaved and decomposed by irradiation with active energy rays to generate radicals is known. agent. However, when a cleavage-type photopolymerization initiator is used for the polyisobutylene used in the present invention, the main chain of the polyisobutylene is cut by the photopolymerization initiator that generates radicals, and crosslinking cannot proceed. In the present invention, by using a hydrogen abstraction type photopolymerization initiator, the crosslinking of polyisobutylene can be performed as described above.

Examples of the hydrogen abstraction type photopolymerization initiator include acetophenone, benzophenone, methyl phthaloylbenzoate-4-phenylbenzophenone, and 4,4'-dichlorodibenzophenone. Ketone, hydroxybenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-dichlorobenzophenone, 4,4'-dimethylbenzophenone, 4-benzene Formyl-4'-methyl-diphenyl sulfide, acrylated benzophenone, 3,3',4,4'-tetrakis(tert-butylcarbonylperoxide)benzophenone, 3,3'- Benzophenone-based compounds such as dimethyl-4-methoxybenzophenone; 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthene Ketones, thioxanthone-based compounds such as 2,4-dichlorothioxanthone, etc.; amino groups such as 4,4'-bis(dimethylamino)benzophenone and 4,4'-diethylaminobenzophenone Benzophenone series compounds; 10-butyl-2-chloroacridone, 2-ethylanthraquinone, 9,10-phenanthrenequinone, camphorquinone, etc.; naphthophenone, 1-hydroxycyclohexyl phenyl ketone, etc. Aromatic ketone compounds; aromatic aldehydes such as terephthalaldehyde, and quinone-based aromatic compounds such as methylanthraquinone. These can be used individually by 1 type, or can be used in mixture of 2 or more types. Among them, from the viewpoint of reactivity, benzophenone-based compounds are preferable, and benzophenone is more preferable.

The content of the hydrogen abstraction type photopolymerization initiator is preferably 0.001 to 10 parts by weight, more preferably 0.005 to 10 parts by weight, and even more preferably 0.01 to 10 parts by weight relative to 100 parts by weight of the polyisobutylene. By including the hydrogen abstraction type photopolymerization initiator within the above range, the crosslinking reaction can be advanced to the target density, which is preferable.

In addition, in the present invention, a cleavage-type photopolymerization initiator may be used together with the hydrogen abstraction-type photopolymerization initiator within a range that does not impair the effects of the present invention, but it is preferably not used for the aforementioned reasons.

The rubber-based adhesive used in the present invention may further contain a polyfunctional radically polymerizable compound. In the present invention, the polyfunctional radically polymerizable compound functions as a crosslinking agent for polyisobutylene.

The polyfunctional radically polymerizable compound is a compound having at least two (meth)acryloyl groups or a radically polymerizable functional group having an unsaturated double bond, such as a vinyl group. Specific examples of the polyfunctional radically polymerizable compound include tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate, for example. Acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 2-ethyl-2-butylpropanediol di(meth)acrylate , bisphenol A di(meth)acrylate, bisphenol A ethylene oxide adduct di(meth)acrylate, bisphenol A propylene oxide adduct di(meth)acrylate, bisphenol A Diglycidyl ether di(meth)acrylate, neopentyl glycol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, dioxanediol di(meth)acrylate base) acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate Ester products of (meth)acrylic acid such as meth)acrylate and EO-modified diglycerol tetra(meth)acrylate and polyhydric alcohol, 9,9-bis[4-(2-(meth)acryloyloxy) Ethoxy) phenyl] fluorene and so on. These can be used individually by 1 type, or can be used as a mixture of 2 or more types. Among them, from the viewpoint of compatibility with polyisobutylene, esterified products of (meth)acrylic acid and polyol are preferred, and bifunctional (meth)acrylates having two (meth)acryloyl groups are more preferred, and those having two (meth)acryloyl groups are more preferred. The trifunctional (meth)acrylate having three or more (meth)acryloyl groups is particularly preferably tricyclodecane dimethanol di(meth)acrylate and trimethylolpropane tri(meth)acrylate.

The content of the polyfunctional radically polymerizable compound is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, and even more preferably 10 parts by weight or less, based on 100 parts by weight of the polyisobutylene. In addition, the lower limit of the content of the polyfunctional radically polymerizable compound is not particularly limited. For example, it is preferably 0.1 part by weight or more, more preferably 0.5 part by weight or more, and still more preferably 1 part by weight with respect to 100 parts by weight of the polyisobutylene. above. It is preferable from a viewpoint of the durability of the rubber-type adhesive layer obtained by making content of a polyfunctional radically polymerizable compound into the said range.

Although the molecular weight of a polyfunctional radically polymerizable compound is not specifically limited, For example, it is preferable that it is about 1000 or less, and it is more preferable that it is about 500 or less.

The rubber-based pressure-sensitive adhesive used in the present invention may contain at least one kind of tackifier selected from the group consisting of a terpene skeleton-containing tackifier, a rosin skeleton-containing tackifier, and their hydrogenated compounds. By including a tackifier in the rubber-based pressure-sensitive adhesive, it is possible to form a rubber-based pressure-sensitive adhesive layer having high adhesiveness to various adherends and high durability even in a high-temperature environment, which is preferable.

Examples of the tackifier including the terpene skeleton include terpene polymers such as α-pinene polymers, β-pinene polymers, and dipentene polymers, and modified terpene polymers. Modified terpene resins and the like obtained from properties (phenol modification, styrene modification, aromatic modification, hydrogenation modification, hydrocarbon modification, etc.). Examples of the above-mentioned modified terpene resins include terpene phenol resins, styrene-modified terpene resins, aromatic modified terpene resins, hydrogenated terpene resins (hydrogenated terpene resins), and the like. Examples of the hydrogenated terpene resin mentioned here include hydrogenated products of terpene polymers, other modified terpene resins, and hydrogenated products of terpene phenol resins. Among them, hydrogenated products of terpene phenol resins are preferred from the viewpoints of compatibility with rubber-based adhesives and adhesive properties.

Examples of the tackifier containing the rosin skeleton include rosin resin, polymerized rosin resin, hydrogenated rosin resin, rosin ester resin, hydrogenated rosin ester resin, rosin phenol resin, etc. Specifically, gum rosin and wood rosin can be used , Unmodified rosin (raw rosin) such as tall oil rosin, or modified rosin that has undergone hydrogenation, disproportionation, polymerization, or other chemical modifications, and their derivatives.

As the thickener, commercially available products such as Clearon series, Polyster series, Super Ester series, Bensel series, and Pinecrystal series manufactured by Yasuhara Chemical Co., Ltd., and Arakawa Chemical Industry Co., Ltd. can be used, for example.

When the tackifier is a hydride, the hydrogenation may be a partially hydrogenated partial hydride or a full hydride in which all double bonds in the compound are hydrogenated. In the present invention, from the viewpoints of adhesive properties, weather resistance, or color tone, perhydrogen compounds are preferred.

From the viewpoint of adhesive properties, it is preferable that the tackifier contains a cyclohexanol skeleton. Although the detailed principle is unknown, it is considered that the cyclohexanol skeleton is more compatible with the polyisobutylene as the base polymer than the phenol skeleton. As the tackifier containing a cyclohexanol skeleton, for example, hydrogenated products such as terpene phenol resins and rosin phenol resins are preferable, and perhydrogenated products such as terpene phenol resins and rosin phenol resins are more preferable.

Although the softening point (softening temperature) of the said tackifier is not specifically limited, For example, it is preferable that it is about 80 degreeC or more, and it is more preferable that it is about 100 degreeC or more. By setting the softening point of the tackifier to be 80° C. or higher, the tackifier is not softened even at a high temperature and the adhesive properties can be maintained, which is preferable. The upper limit of the softening point of the tackifier is not particularly limited. However, if the softening point is too high, the molecular weight is higher, the compatibility is deteriorated, and problems such as whitening may occur. Therefore, for example, it is preferably about 200°C or lower. , more preferably about 180°C or lower. In addition, the softening point of tackifier resin mentioned here is defined as the value measured by the softening point test method (ring and ball method) prescribed|regulated by any one of JISK5902 and JISK2207.

The weight average molecular weight (Mw) of the tackifier is not particularly limited, but is preferably 50,000 or less, more preferably 30,000 or less, still more preferably 10,000 or less, still more preferably 8,000 or less, and particularly preferably 5,000 or less. Moreover, although the lower limit of the weight average molecular weight of the said tackifier is not specifically limited, 500 or more are preferable, 1000 or more are more preferable, and 2000 or more are more preferable. When the weight average molecular weight of the tackifier is within the above-mentioned range, compatibility with polyisobutylene is good, and troubles such as whitening do not occur, which is preferable.

The addition amount of the tackifier is preferably 40 parts by weight or less, more preferably 30 parts by weight or less, and further preferably 20 parts by weight or less with respect to 100 parts by weight of the polyisobutylene. Moreover, although the lower limit of the addition amount of a tackifier is not specifically limited, Preferably it is 0.1 weight part or more, More preferably, it is 1 weight part or more, More preferably, it is 5 weight part or more. By making the usage-amount of a tackifier into the said range, since adhesive characteristics can be improved, it is preferable. Moreover, when the usage-amount of a tackifier exceeds the said range and adds in a large amount, since the cohesion force of an adhesive tends to fall, it is unpreferable.

Moreover, you may add a tackifier other than the said terpene skeleton-containing tackifier and the rosin skeleton-containing tackifier to the rubber-based pressure-sensitive adhesive used in the present invention. As this tackifier, a petroleum resin-based tackifier can be mentioned. Examples of the petroleum-based tackifier include aromatic petroleum resins, aliphatic petroleum resins, alicyclic petroleum resins (alicyclic petroleum resins), aliphatic/aromatic petroleum resins, and aliphatic petroleum resins. aliphatic/alicyclic petroleum resins, hydrogenated petroleum resins, coumarone-based resins, coumarone-indene-based resins, etc.

The petroleum resin-based tackifier can be used within a range that does not impair the effects of the present invention, and can be used, for example, in an amount of about 30 parts by weight or less with respect to 100 parts by weight of the polyisobutylene.

In the rubber-based adhesive, an organic solvent may be added as a diluent. Although it does not specifically limit as a diluent, For example, toluene, xylene, n-heptane, dimethyl ether, etc. are mentioned, These can be used individually by 1 type or in mixture of 2 or more types. Among them, toluene is preferable.

The addition amount of the diluent is not particularly limited, but in the rubber-based adhesive, it is preferably added at about 50 to 95% by weight, and more preferably about 70 to 90% by weight. It is preferable from a viewpoint of coatability to a support etc. by making the addition amount of a diluent into the said range.

To the rubber-based adhesive used in the present invention, additives other than those described above may be added within a range that does not impair the effects of the present invention. Specific examples of additives include softeners, crosslinking agents (for example, polyisocyanates, epoxy compounds, alkyl etherified melamine compounds, etc.), fillers, antiaging agents, ultraviolet absorbers, and the like. The kind, combination, addition amount, and the like of the additives to be added to the rubber-based adhesive can be appropriately set according to the purpose. The content (total amount) of the additive in the rubber-based adhesive is preferably 30% by weight or less, more preferably 20% by weight or less, and even more preferably 10% by weight or less.

The rubber-based pressure-sensitive adhesive layer used in the present invention can be formed from the above-mentioned pressure-sensitive adhesive, and the production method thereof is not particularly limited. The pressure-sensitive adhesive can be applied to various supports and the like, dried by heating, irradiated with active energy rays, and the like. An adhesive layer is formed.

When polyisobutylene is contained as the rubber-based adhesive, it is preferable to irradiate the adhesive with active energy rays to crosslink the polyisobutylene. For irradiation of active energy rays, the rubber-based adhesive is usually applied to various supports and the like, and the resulting coating layer is irradiated.

In addition, the irradiation of the active energy ray may be directly irradiated to the coating layer (without bonding other members, etc.), or may be irradiated after bonding the coating layer to various members such as optical films such as separators and glass. In the case of irradiating after bonding with the optical film and various members, active energy rays may be irradiated through the optical film and various members, or the optical film and various members may be peeled off, and the The surface is irradiated with active energy rays.

As the coating method of the adhesive, various methods can be used. Specifically, for example, roll coating, roll lick coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, blade coating, air knife coating, curtain coating, Methods such as die lip coating and extrusion coating using a die coater or the like.

When heating and drying the coating layer of the adhesive, the heating drying temperature is preferably about 30°C to 200°C, more preferably 40°C to 180°C, and even more preferably 80°C to 150°C. By making the heating temperature into the above-mentioned range, a pressure-sensitive adhesive layer having excellent adhesive properties can be obtained. As the drying time, a suitable time can be appropriately adopted. The drying time is preferably about 5 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, and even more preferably 1 minute to 8 minutes.

In addition, in the case of irradiating the coating layer of the adhesive with active energy rays, when the adhesive or the adhesive contains an organic solvent as a diluent, it is also preferable to irradiate the active energy ray after coating. The solvent and the like are removed by heating and drying beforehand.

The heating and drying temperature is not particularly limited, but from the viewpoint of reducing residual solvent, it is preferably about 30°C to 90°C, and more preferably about 60°C to 80°C. As the drying time, a suitable time can be appropriately adopted. The drying time is preferably about 5 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, and even more preferably 1 minute to 8 minutes.

Examples of the active energy rays include visible rays, ultraviolet rays, electron beams, and the like, and among them, ultraviolet rays are preferable.

^The irradiation conditions of the ultraviolet rays are not particularly limited, and can be set to any appropriate conditions according to the composition of the rubber ^- based adhesive to be crosslinked.

As the support, for example, a peeled sheet (separator) can be used.

Examples of the constituent material of the separator include plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films, porous materials such as paper, cloth, and nonwoven fabrics, nets, and foams. Sheets, metal foils, and appropriate paper-like objects such as laminates thereof, etc., but plastic films can be suitably used from the viewpoint of being excellent in surface smoothness.

Examples of the plastic film include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, and polyparaphenylene. Polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene-vinyl acetate copolymer film, etc.

The thickness of the separator is usually 5 to 200 μm, preferably about 5 to 100 μm. For the separator, if necessary, mold release using silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based mold release agents, silica powder, etc., as well as antifouling treatment, coating type can also be performed , Internal plus type, evaporation type and other anti-static treatment. In particular, the peelability from the pressure-sensitive adhesive layer can be further improved by appropriately performing peeling treatments such as silicone treatment, long-chain alkyl treatment, and fluorine treatment on the surface of the separator.

When the pressure-sensitive adhesive layer is formed on the sheet (separator) subjected to the peeling process, the pressure-sensitive adhesive layer can be transferred onto a polarizing film to form the polarizing plate of the present invention.

The thickness of the pressure-sensitive adhesive layer is not particularly limited and can be appropriately set according to the application, but is preferably 250 μm or less, more preferably 100 μm or less, and further preferably 55 μm or less. In addition, the lower limit of the thickness of the pressure-sensitive adhesive layer is not particularly limited, but from the viewpoint of durability, it is preferably 1 μm or more, more preferably 5 μm or more, and further preferably more than 15 μm.

The gel fraction of the pressure-sensitive adhesive layer used in the present invention is not particularly limited, but is preferably about 10 to 98%, more preferably about 25 to 98%, and further preferably about 45 to 90%. By making the gel fraction within the above-mentioned range, durability and adhesive force can be achieved at the same time, which is preferable.

The composition of the polyolefin-based adhesive is not particularly limited as long as it contains a polyolefin-based resin.

Specific examples of the polyolefin-based resin include low-density polyethylene, ultra-low-density polyethylene, low-crystalline polypropylene, amorphous propylene-(1-butene) copolymer, ionomer resin, ethylene-acetic acid Ethylene copolymers such as vinyl ester copolymers, ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylate-maleic anhydride copolymers, and ethylene-glycidyl methacrylate copolymers, polyolefin modified polymerization things etc.

The pressure-sensitive adhesive layer more preferably contains an amorphous polypropylene-based resin, and further preferably contains an amorphous propylene-(1-butene) copolymer. If it is such a pressure-sensitive adhesive layer, a pressure-sensitive adhesive sheet which is further excellent in step followability can be obtained. In addition, in this specification, "amorphous state" means the property which does not have a clear melting point like a crystal.

The content ratio of the amorphous propylene-(1-butene) copolymer contained in the pressure-sensitive adhesive can be appropriately adjusted so that the elasticity value of the pressure-sensitive adhesive layer is 0.7 N/mm or less. The content ratio of the amorphous propylene-(1-butene) copolymer contained in the adhesive is preferably 10 to 100% by weight, and more preferably 10 to 95% by weight in terms of weight ratio.

The above-mentioned amorphous propylene-(1-butene) copolymer can be preferably obtained by polymerizing propylene and 1-butene using a metallocene catalyst. More specifically, for example, by performing a polymerization step of polymerizing propylene and 1-butene using a metallocene catalyst, and after the polymerization step, performing post-treatment steps such as a catalyst residue removal step and a foreign matter removal step, an amorphous material can be obtained. propylene-(1-butene) copolymer. Through such a process, an amorphous propylene-(1-butene) copolymer can be obtained, for example, in a powder form, a granular form, or the like. Examples of the metallocene catalyst include a metallocene homogeneously mixed catalyst containing a metallocene compound and an aluminoxane, a metallocene-supported catalyst in which a metallocene compound is supported on a particulate carrier, and the like.

Amorphous propylene-(1-butene) copolymers polymerized using metallocene catalysts as described above show narrow molecular weight distributions. The molecular weight distribution (Mw/Mn) of the amorphous propylene-(1-butene) copolymer is preferably 3 or less, more preferably 2 or less, still more preferably 1.1 to 2, and particularly preferably 1.2 to 1.9. Amorphous propylene-(1-butene) copolymers with a narrow molecular weight distribution have few low-molecular-weight components. Therefore, if such an amorphous propylene-(1-butene) copolymer is used, it is possible to prevent An adhesive layer contaminated by adherends due to exudation of components.

The content ratio of the constituent unit derived from propylene in the amorphous propylene-(1-butene) copolymer is preferably 80 mol % to 99 mol %, more preferably 85 mol % to 99 mol %, and still more preferably 90 mol % %～99mol%.

The content ratio of the constituent unit derived from 1-butene in the amorphous propylene-(1-butene) copolymer is preferably 1 mol % to 20 mol %, more preferably 1 mol % to 15 mol %, and further preferably It is 1 mol% to 10 mol%. Within such a range, a pressure-sensitive adhesive layer excellent in the balance between toughness and flexibility can be obtained.

The above-mentioned amorphous propylene-(1-butene) copolymer may be a block copolymer or a random copolymer.

The weight average molecular weight (Mw) of the amorphous propylene-(1-butene) copolymer is preferably 200,000 or more, more preferably 200,000 to 500,000, and even more preferably 200,000 to 300,000. When the weight average molecular weight (Mw) of the amorphous propylene-(1-butene) copolymer is in this range, the molecular weight is lower than that of general styrene-based thermoplastic resins and acrylic-based thermoplastic resins (Mw is 100,000 or less). There are few components, and the adhesive layer which can prevent contamination of an adherend can be obtained.

The melt flow rate of the above-mentioned amorphous propylene-(1-butene) copolymer at 230°C and 2.16kgf is preferably 1g/10min～50g/10min, more preferably 5g/10min～30g/10min, still more preferably It is 5g/10min～20g/10min. When the melt flow rate of the amorphous propylene-(1-butene) copolymer is in such a range, a pressure-sensitive adhesive layer having a uniform thickness can be formed without poor processing by co-extrusion. The melt flow rate can be measured by the method according to JISK7210.

The above-mentioned amorphous propylene-(1-butene) copolymer may further contain structural units derived from other monomers within a range that does not impair the effects of the present invention. Examples of other monomers include ethylene, 1-pentene, 1-hexene, 1-octene, 1-decene, 4-methyl-1-pentene, and 3-methyl-1-pentene etc. α-olefins, etc.

The above-mentioned amorphous propylene-(1-butene) copolymer may further contain structural units derived from other monomers within a range that does not impair the effects of the present invention. Examples of other monomers include ethylene, 1-pentene, 1-hexene, 1-octene, 1-decene, 4-methyl-1-pentene, and 3-methyl-1-pentene etc. α-olefins, etc.

The pressure-sensitive adhesive layer preferably further contains a crystalline polypropylene-based resin. By containing the crystalline polypropylene resin, the elastic modulus E' at 70°C of the pressure-sensitive adhesive layer can be adjusted to a desired value. The content ratio of the crystalline polypropylene-based resin can be set to any appropriate ratio according to the desired elastic modulus E'. The content ratio of the crystalline polypropylene-based resin is preferably 0% by weight to 90% by weight relative to the total weight of the amorphous propylene-(1-butene) copolymer and the crystalline polypropylene-based resin. , more preferably 5% by weight to 90% by weight.

The above-mentioned crystalline polypropylene-based resin may be homopolypropylene, or may be a copolymer obtained from propylene and a monomer copolymerizable with propylene. Examples of monomers copolymerizable with propylene include ethylene, 1-pentene, 1-hexene, 1-octene, 1-decene, 4-methyl-1-pentene, and 3-methyl- α-olefins such as 1-pentene, etc. When the above-mentioned crystalline polypropylene-based resin is a copolymer obtained from propylene and a monomer copolymerizable with propylene, it may be a random copolymer or a block copolymer.

The above-mentioned crystalline polypropylene-based resin is preferably obtained by polymerizing using a metallocene catalyst similarly to the above-mentioned amorphous propylene-(1-butene) copolymer. When the crystalline polypropylene-based resin obtained as described above is used, contamination of the adherend due to exudation of low molecular weight components can be prevented.

The degree of crystallinity of the crystalline polypropylene-based resin is preferably 10% or more, and more preferably 20% or more. The degree of crystallinity is typically determined by differential scanning calorimetry (DSC) or X-ray diffraction.

Preferably, the pressure-sensitive adhesive layer does not substantially contain F ⁻ , Cl ⁻ , Br ⁻ , NO ₂ ⁻ , NO ₃ ⁻ , SO ₄ ²⁻ , Li ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ , NH ₄₊ ^. This is because the ions can be prevented from contaminating the adherend. The pressure-sensitive adhesive layer not containing the above-mentioned ions can be obtained, for example, by solution-polymerizing the amorphous propylene-(1-butene) copolymer contained in the pressure-sensitive adhesive layer using a metallocene catalyst as described above.

In the solution polymerization using this metallocene catalyst, the amorphous propylene-(1-butene) copolymer can be purified by repeated precipitation separation (reprecipitation method) using a poor solvent different from the polymerization solvent, so that it is possible to obtain non-crystalline An adhesive layer containing the above-mentioned ions. In addition, in this specification, the so-called “substantially does not contain F ⁻ , Cl ⁻ , Br ⁻ , NO ₂ ⁻ , NO ₃ ⁻ , SO ₄ ²⁻ , Li ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ , NH ₄ ⁺ ” means less than the detection limit in standard ion chromatographic analysis (for example, ion chromatographic analysis using Dionex Corporation, trade names “DX-320” and “DX-500”). Specifically, it means that F ⁻ , Cl ⁻ , Br ⁻ , NO ₂ ⁻ , NO ₃ ⁻ , SO ₄ ² − , and K ⁺ are respectively 0.49 μg or less, Li ⁺ and Na ⁺ with respect to the pressure-sensitive adhesive layer 1 g They are 0.20 μg or less, Mg ²⁺ and Ca ²⁺ are 0.97 μg or less, and NH ₄ ⁺ is 0.5 μg or less, respectively.

The said pressure-sensitive adhesive layer may further contain other components in the range which does not impair the effect of this invention. As this other component, antioxidant, an ultraviolet absorber, a light stabilizer, a heat-resistant stabilizer, an antistatic agent etc. are mentioned, for example. The kind and usage amount of other components can be appropriately selected according to the purpose.

The polyolefin-based pressure-sensitive adhesive layer used in the present invention can be formed from the above-mentioned pressure-sensitive adhesive, and its production method is not particularly limited. irradiation, etc., to form an adhesive layer.

The molding temperature in the above extrusion molding is preferably 160°C to 220°C, and more preferably 170°C to 200°C. Within such a range, the molding stability is excellent.

As the support, for example, a peeled sheet (separator) can be used.

Examples of the constituent material of the separator include plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films, porous materials such as paper, cloth, and nonwoven fabrics, nets, and foams. Sheets, metal foils, and appropriate paper-like objects such as laminates thereof, etc., but plastic films can be suitably used from the viewpoint of being excellent in surface smoothness.

Examples of the plastic film include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, and polyparaphenylene. Polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene-vinyl acetate copolymer film, etc.

The thickness of the separator is usually 5 to 200 μm, preferably about 5 to 100 μm. The separator may be subjected to mold release, antifouling treatment, or coating using a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based mold release agent, silica powder, etc., as necessary Anti-static treatment such as type, internal addition type, and evaporation type. In particular, the peelability from the pressure-sensitive adhesive layer can be further improved by appropriately performing peeling treatments such as silicone treatment, long-chain alkyl treatment, and fluorine treatment on the surface of the separator.

When the pressure-sensitive adhesive layer is formed on the sheet (separator) subjected to the peeling process, the pressure-sensitive adhesive layer can be transferred onto a polarizing film to form the polarizing plate of the present invention.

The thickness of the pressure-sensitive adhesive layer is not particularly limited and can be appropriately set according to the application, but is preferably 250 μm or less, more preferably 100 μm or less, and further preferably 55 μm or less. In addition, the lower limit of the thickness of the pressure-sensitive adhesive layer is not particularly limited, but from the viewpoint of durability, it is preferably 1 μm or more, more preferably 5 μm or more, and further preferably more than 15 μm.

＜Other floors＞

The polarizing plate of this invention can be used for liquid crystal display devices etc. as it is, for example, However, it can be used for various uses by further providing a functional layer to the surface opposite to the polarizing film side of the said adhesive bond layer. That is, the adhesive layer may be a layer for laminating the polarizing film and the functional layer. The functional layer may be the aforementioned protective film, reflective polarizing film, viewing angle compensation film, λ/4 plate, λ/2 plate and other retardation films.

As said functional layer, a reflective polarizing film is mentioned, for example. An example of a reflective polarizing film is an anisotropic multiplex thin film that transmits linearly polarized light in one vibration direction and reflects linearly polarized light in the other vibration direction, and a specific example thereof is DBEF (Japanese Patent Laid-Open No. 4-268505) manufactured by 3M. Gazette, etc.). Another example of the anisotropic reflective polarizer is a composite of a cholesteric liquid crystal layer and a λ/4 plate, and a specific example thereof is PCF manufactured by Nitto Denko (Japanese Patent Laid-Open No. 11-231130, etc.). Another example of the anisotropic reflective polarizer is a reflective grid polarizer, specific examples of which are metal lattice reflective polarizers that perform microprocessing on metals and emit reflective polarized light even in the visible light region (US Patent No. 6,288,840 Specification, etc.), A film in which metal fine particles are added to a polymer matrix and stretched (Japanese Patent Laid-Open No. 8-184701 ) and the like.

In addition, as the functional layer, a viewing angle compensation film used in a liquid crystal display device, a well-known λ/4 plate for imparting a circular polarization function, and the like are preferably used.

In the polarizing plate of the present invention, in order to be laminated on an image display device, the surface of the protective film on the opposite side to the surface to which the polarizing film is bonded, and the surface of the functional film on the opposite side to the surface to which the pressure-sensitive adhesive layer is bonded may be provided. The side surfaces, or both sides thereof, are further provided with an adhesive layer.

The binder to be used is not particularly limited, and known binders can be used. As the pressure-sensitive adhesive layer, the same pressure-sensitive adhesive as the pressure-sensitive adhesive described above with a water vapor transmission rate of 100 g/(m ² ·day) or less under the conditions of a temperature of 40° C. and a relative humidity of 92% RH may be used. Use a different adhesive.

As a binder different from the above-mentioned binder, for example, acrylic polymer, silicone polymer, polyester, polyurethane, polyamide, polyvinyl ether, vinyl acetate/vinyl chloride copolymer can be appropriately selected and used. It is used as a binder for the base polymer, such as polymers, modified polyolefins, epoxy-based, fluorine-based, natural rubber, synthetic rubber and other rubber-based polymers. As the adhesive, an adhesive that is excellent in optical transparency, exhibits moderate wettability, cohesiveness, and adhesive properties, and is excellent in weather resistance, heat resistance, and the like is particularly preferable.

The pressure-sensitive adhesive layer may be any pressure-sensitive adhesive that is excellent in optical transparency and exhibits adequate wettability, cohesiveness, and adhesive properties such as adhesiveness. However, it is preferable to use an adhesive that is excellent in durability and the like. agent. Specifically, as an adhesive which forms an adhesive layer, the pressure-sensitive adhesive (also called acrylic adhesive) containing an acrylic resin is mentioned, for example.

The adhesive layer formed of the acrylic adhesive is not particularly limited, but butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate, and (meth)acrylate are preferably used ) (meth)acrylate resins such as 2-ethylhexyl acrylate, or copolymer resins using two or more of these (meth)acrylates. In addition, polar monomers are copolymerized in these resins. Examples of polar monomers include (meth)acrylic acid, 2-hydroxypropyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, (meth)acrylamide, and (meth)acrylic acid. Monomers having polar functional groups such as carboxyl groups, hydroxyl groups, amide groups, amino groups, and epoxy groups, such as 2-N,N-dimethylaminoethyl ester and glycidyl (meth)acrylate. In addition, a crosslinking agent is usually blended with an acrylic resin in the adhesive.

In addition to this, various additives can be blended in the adhesive. Suitable additives include silane coupling agents and antistatic agents. A silane coupling agent is effective in improving the adhesive force with glass. Antistatic agents are effective in reducing or preventing the generation of static electricity. That is, when the polarizing plate is attached to the liquid crystal cell via the pressure-sensitive adhesive layer, the surface protective film (separator) previously covered with the pressure-sensitive adhesive layer and temporarily protected is peeled off and then attached to the liquid crystal cell. Static electricity generated at the time of protecting the film may cause poor alignment in the liquid crystal in the cell, and this poor alignment may lead to poor display of the liquid crystal display device.

In reducing or preventing the generation of such static electricity, it is effective to mix antistatic agents.

The thickness of at least one of the adhesives is preferably 3 to 50 μm. More preferably, it is 3-30 micrometers.

In the case where the pressure-sensitive adhesive layer is made conductive, the resistance value may be appropriately selected, and for example, it is preferably in the range of 1×10 ⁹ to 1×10 ¹¹ Ω/□.

The formation method of the said adhesive layer formed in a polarizing plate can be performed by a well-known method.

<Image display device>

The image display device of the present invention is characterized by having the polarizing plate of the present invention. The polarizing plate of the present invention may be a circular polarizing plate further including a λ/4 plate.

The polarizing plate of the present invention is applicable to a known image display device, and the type of the image display device is not limited. For example, the polarizing plate of the present invention can be suitably used in a liquid crystal display device and an organic EL display device.

The image display device may be a flexible image display device. The flexible image display device includes a laminate for a flexible image display device and an organic EL display panel, and the laminate for a flexible image display device is arranged on the visible side with respect to the organic EL display panel, and is configured to be bendable. The laminate for a flexible image display device may contain a window, the polarizing plate of the present invention, and a touch sensor, and the stacking order of these may be arbitrary. , touch sensor, polarizing plate of the present invention. When a polarizing plate is present on the visible side of the touch sensor, the pattern of the touch sensor is difficult to be observed, and the visibility of the displayed image is improved, which is preferable. The respective members may be laminated using adhesives, adhesives, or the like. In addition, a light-shielding pattern formed on at least one side of any layer of the window, the polarizing plate, and the touch sensor may be provided.

[window]

The window is arranged on the visible side of the flexible image display device, and plays a role of protecting other components from external shocks and environmental changes such as temperature and humidity. Conventionally, glass has been used as such a protective layer, but the window of a flexible image display device is not rigid and hard like glass, but has a flexible property. The window may be formed from a flexible transparent substrate comprising a hard coat on at least one side.

(transparent substrate)

The visible light transmittance of the transparent substrate is 70% or more, preferably 80% or more. As long as the transparent base material is a polymer film having transparency, any material can be used. Specifically, the transparent substrate may be polyolefins such as polyethylene, polypropylene, polymethylpentene, cycloolefin derivatives having a unit containing a monomer including norbornene or cycloolefin, and diacetyl cellulose. , (modified) celluloses such as triacetyl cellulose, propionyl cellulose, acrylics such as methyl methacrylate (co)polymers, polystyrenes such as styrene (co)polymers, acrylonitrile/butylene Diene/styrene copolymers, acrylonitrile/styrene copolymers, ethylene-vinyl acetate copolymers, polyvinyl chloride, polyvinylidene chloride, polyethylene terephthalate, polyethylene Polyester such as butylene terephthalate, polyethylene naphthalate, polycarbonate, polyarylate, polyamide such as nylon, polyimide, polyamideimide, polyamide Films formed of polymers such as etherimides, polyethersulfones, polysulfones, polyvinyl alcohols, polyvinyl acetals, polyurethanes, and epoxy resins. These polymers can be used alone or in combination of two or more. Among the transparent substrates described above, polyamide films, polyamideimide films or polyimide films, polyester-based films, olefin-based films, acrylic-based films, and cellulose-based films, which are excellent in transparency and heat resistance, are preferred. membrane. It is also preferable to disperse inorganic particles such as silica, organic fine particles, rubber particles, and the like in the polymer film. In addition, colorants such as pigments and dyes, optical brighteners, dispersants, plasticizers, heat stabilizers, light stabilizers, infrared absorbers, ultraviolet absorbers, antistatic agents, antioxidants, lubricants agents, solvents, etc. The thickness of the transparent substrate is 5-200 μm, preferably 20-100 μm. The transparent substrate may be an unstretched film, a uniaxially stretched film or a biaxially stretched film.

(hard coating)

A hard coat layer may be provided on at least one side of the transparent substrate in the window. The thickness of the hard coat layer is not particularly limited, but may be, for example, 2 to 100 μm.

When the thickness of the hard coat layer is less than 2 μm, it is difficult to ensure sufficient impact resistance and scratch resistance, and when the thickness is greater than 100 μm, the bending resistance decreases and the problem of curling due to curing shrinkage may occur.

The hard coat layer may be a cured layer of a hard coat layer composition containing a reactive material that forms a crosslinked structure by irradiating active energy rays or thermal energy. Examples of active energy rays include visible light, ultraviolet rays, infrared rays, X-rays, alpha rays, beta rays, gamma rays, and electron beams. Ultraviolet rays are particularly preferred. The hard coat composition contains at least one polymer of a radically polymerizable compound and a cationically polymerizable compound. A polymerization initiator may be further included in the hard coat composition. The hard coat composition may further contain one or more selected from solvents and additives. Examples of additives include inorganic particles, leveling agents, stabilizers, surfactants, antistatic agents, lubricants, antifouling agents, and the like.

[touch sensor]

A touch sensor can be used as an input mechanism. As the touch sensor, various types such as a resistive film method, a surface acoustic wave method, an infrared method, an electromagnetic induction method, and an electrostatic capacitance method are proposed, and any method may be used. Among them, the electrostatic capacitance method is preferable. The electrostatic capacitance type touch sensor is divided into an active area and an inactive area located at the outer portion of the active area. The active area corresponds to the area (display portion) of the display panel that displays the screen and senses the user's touch, and the inactive area corresponds to the area (non-display portion) of the display device where the screen is not displayed. The touch sensor may include: a substrate having flexible properties; a sensing pattern formed on an active area of the substrate; and an inactive area formed on the substrate for driving with the outside via the sensing pattern and the pad portion Each sense line connected to the circuit. As the substrate having flexibility, the same material as the transparent substrate of the window can be used. For the substrate of the touch sensor, from the viewpoint of suppressing cracks that may occur in the touch sensor, a substrate having a toughness of 2000 MPa% or more is preferable. More preferably, the toughness is 2000 MPa% to 30000 MPa%. Here, toughness is defined as the lower area of the curve up to the breaking point in a stress (MPa)-strain (%) curve (Stress-Strain Curve) obtained by a tensile test of the polymer material.

[adhesive layer]

Each layer (window, circular polarizing plate, touch sensor) forming the laminate for flexible image display devices and film members (linear polarizing plate, λ/4 retardation plate, etc.) constituting each layer can be laminated with an adhesive. As the adhesive, water-based adhesives, organic solvent-based, solvent-free adhesives, solid adhesives, solvent-volatile adhesives, moisture-curable adhesives, heat-curable adhesives, Anaerobic curing type, active energy ray curing type adhesive, curing agent mixed type adhesive, hot melt type adhesive, pressure sensitive adhesive (adhesive), rewet type adhesive, etc. adhesive. Among them, water-based solvent-volatile adhesives, active energy ray-curable adhesives, and adhesives are commonly used. The thickness of the adhesive bond layer can be appropriately adjusted according to the required adhesive force and the like, and is 0.01 μm to 500 μm, preferably 0.1 μm to 300 μm. When the laminated body for flexible image display devices includes a plurality of adhesive layers, the respective thicknesses and types may be the same or different.

[shading pattern]

The shading pattern may be applied as at least a part of a frame or a casing of a flexible image display device. The light-shielding pattern shields the wirings arranged at the edge of the flexible image display device so as to be difficult to observe. The light-shielding pattern may be in the form of a single layer or multiple layers. The color of the light-shielding pattern is not particularly limited, and black, white, metallic color, etc. can be mentioned. The light-shielding pattern can be formed of a pigment and a polymer such as an acrylic resin, an ester resin, an epoxy resin, a polyurethane, and a silicone. The light-shielding pattern can be formed by various methods such as printing, photolithography, and inkjet. The thickness of the light-shielding pattern may be 1 μm to 100 μm, preferably 2 μm to 50 μm. In addition, it is also preferable to give a shape such as an inclination in the thickness direction of the light-shielding pattern.

Example

Hereinafter, although an Example is given and this invention is demonstrated more concretely, this invention is not limited to these Examples. In an example, the parts and % indicating the content or usage amount are based on weight unless otherwise specified. In addition, the measurement of each physical property in the following example was performed by the following method.

(1) Determination of thickness:

Measured using a digital micrometer "MH-15M" manufactured by Nikon Corporation.

(2) Measurement of the moisture permeability of the adhesive bond layer

A triacetyl cellulose film (TAC film, thickness: 25 μm, manufactured by Konica Minolta Co., Ltd.) was bonded to the adhesive surface of the pressure-sensitive adhesive sheet (thickness of pressure-sensitive adhesive layer: 50 μm) used in Examples and Comparative Examples. Then, the separator of the adhesive sheet was peeled off, and the sample for measurement was obtained. The adhesive agent was repeatedly apply|coated to the same TAC film as above, and the measurement sample for measuring the water vapor transmission rate of an adhesive bond layer was produced so that the thickness of an adhesive bond layer might be set to 50 micrometers. Then, using these measurement samples, the moisture permeability (water vapor transmission rate) was measured by the moisture permeability test method (cup method, conforming to JIS Z 0208) under the following conditions.

Measurement temperature: 40℃

Relative humidity: 92% R.H.

Measurement time: 24 hours

In the measurement, a constant temperature and humidity chamber was used.

(3) Determination of deiodination amount:

Measured using a digital microscope VHX-1000 manufactured by Keyence Corporation. The amount of deiodination is defined as follows: the evaluation sample is placed in a crossed Nicol state on a polarizing plate for inspection, and a light source is placed on the back of the sample to observe, and the portion where light leaks during observation is taken as the edge relative to the polarizing plate. distance definition.

[Production example 1] Production of polarizing film

A polyvinyl alcohol film with a thickness of 30 μm (average degree of polymerization of about 2400, degree of saponification of 99.9 mol% or more) was uniaxially stretched about 4 times by dry stretching, and then kept in a tensioned state. After being immersed in water for 40 seconds, it was immersed in an aqueous solution having a weight ratio of iodine/potassium iodide/water of 0.052/5.7/100 at 28°C for 30 seconds to perform dyeing treatment. Then, it immersed in the aqueous solution whose weight ratio of potassium iodide/boric acid/water is 11.0/6.2/100 at 70 degreeC for 120 second. Next, after washing with pure water at 8°C for 15 seconds, while maintaining the tension of 300 N, drying at 60°C for 50 seconds, and then drying at 75°C for 20 seconds, the polyvinyl alcohol film with iodine adsorbed and oriented A polarizing film with a thickness of 12 μm.

[Production Example 2] Production of Rubber-Based Adhesive 1

100 parts by weight of polyisobutylene (trade name: OPPANOL B80, Mw: about 750,000, manufactured by BASF Corporation) and tricyclodecanedi as a polyfunctional radically polymerizable compound were adjusted and blended so that the solid content was 15% by weight. Methanol diacrylate (trade name: NK Ester A-DCP, bifunctional acrylate, molecular weight: 304, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) 10 parts by weight, benzophenone ( A toluene solution (binder solution) of 0.5 part by Wako Pure Chemical Industries Ltd.) and 10 parts by weight of perhydroterpene phenol was prepared to prepare a rubber-based binder 1 (solution).

[Production Example 3] Production of rubber-based pressure-sensitive adhesive sheet 1

The rubber-based adhesive 1 (solution) obtained in Production Example 2 was applied to a polyester film (trade name: Diafoil MRF, manufactured by Mitsubishi Plastics Co., Ltd.) with a thickness of 38 μm, which was subjected to a release treatment of silicone for one side. The treated surface is peeled off to form a coating layer. Then, the coating layer was dried at 80° C. for 3 minutes to form a pressure-sensitive adhesive layer, and a pressure-sensitive adhesive sheet having a thickness of the pressure-sensitive adhesive layer of 20 μm was produced. In addition, a 38-μm-thick polyester film (trade name: Diafoil MRF, manufactured by Mitsubishi Plastics Co., Ltd.). The polyester film covering both surfaces of the pressure-sensitive adhesive layer functions as a release film (separator).

One separator was peeled off, and the side from which the separator was peeled was irradiated with ultraviolet rays at room temperature to obtain a pressure-sensitive adhesive sheet composed of the rubber-based pressure-sensitive adhesive layer 1/separator. The ultraviolet rays were irradiated in the UVA region with a light amount of 1000 mJ/cm ² . The moisture permeability was measured using a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer with a thickness of 50 μm prepared by adjusting the coating thickness in the same manner. As a result, the pressure-sensitive adhesive layer had a water vapor transmission rate of 10 g/(m ² ·day).

[Production Example 4] Production of Olefin-Based Adhesive Sheet

As the adhesive layer forming material, an amorphous propylene-(1-butene) copolymer (manufactured by Sumitomo Chemical Co., Ltd., trade name "Tafthren H5002" polymerized with a metallocene catalyst: 90 mol% of propylene-derived structural units /10 mol% of structural units derived from 1-butene, Mw=230000, Mw/Mn=1.8) 60 parts, and a crystalline polypropylene-based resin polymerized with a metallocene catalyst (manufactured by Nippon Polypro Co., Ltd., trade name "" WINTEC WFX4”) 40 parts mixed before use. 100 parts of the above-mentioned pressure-sensitive adhesive layer forming materials were put into an extruder, and T-die melt extrusion was performed (extrusion temperature: 180° C.) to obtain a pressure-sensitive adhesive layer having a thickness of 20 μm. In addition, on the adhesive surface of the adhesive layer, a 38-μm-thick polyester film (trade name), which was peeled off with silicone on one side, was attached so that the peeling-treated surface was in contact with the adhesive layer. : Diafoil MRF, manufactured by Mitsubishi Plastics Co., Ltd.). The polyester film covering both surfaces of the pressure-sensitive adhesive layer functions as a release film (separator). The moisture permeability was measured using a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer with a thickness of 50 μm prepared by separately adjusting extrusion conditions. As a result, the pressure-sensitive adhesive layer had a water vapor transmission rate of 12 g/(m ² ·day).

[Production Example 5] Production of rubber-based adhesive 2

A styrene-ethylene-propylene-styrene block copolymer (SEPS, trade name: SEPTON 2063, styrene content: 13%, styrene-based thermoplastic elastomer, SEPS, trade name: SEPTON 2063, styrene content: 13%, 100 parts by weight (manufactured by Kuraray Co., Ltd.), 40.4 parts by weight of hydrogenated terpene phenol (trade name: YS Polyster TH130, softening point: 130°C, hydroxyl value: 60, manufactured by YASUHARA CHEMICAL Co., Ltd.) as a tackifier, petroleum 61.7 parts of a tackifier (trade name: ピコラスチック A5, vinyltoluene based tackifier, softening point: 5°C, manufactured by Eastman Kodak Co., Ltd.), polybutene (trade name: HV-300, heavyweight) as a softener Average molecular weight: 3000, a toluene solution of 21.3 parts by JX Nippon Mining & Energy Co., Ltd.), and a rubber-based adhesive 2 (solution) was prepared.

[Production Example 6] Production of rubber-based pressure-sensitive adhesive sheet 2

The rubber-based adhesive 2 (solution) obtained in Production Example 5 was applied to a 38-μm-thick polyester film (trade name: Diafoil MRF, manufactured by Mitsubishi Plastics Co., Ltd.) that was peeled off with silicone on one side. The treated surface is peeled off to form a coating layer. Then, the coating layer was dried at 80° C. for 3 minutes to form a pressure-sensitive adhesive layer, and a pressure-sensitive adhesive sheet having a thickness of the pressure-sensitive adhesive layer of 20 μm was produced. In addition, on the adhesive surface of the adhesive sheet, the 38-μm-thick polyester film (product Name: Diafoil MRF, manufactured by Mitsubishi Plastics Co., Ltd.). The polyester film covering both surfaces of the pressure-sensitive adhesive layer functions as a release film (separator).

One separator was peeled off, and the side from which the separator was peeled was irradiated with ultraviolet rays at room temperature to obtain a pressure-sensitive adhesive sheet composed of the rubber-based pressure-sensitive adhesive layer 2/separator. The ultraviolet rays were irradiated in the UVA region with a light amount of 1000 mJ/cm ² . The moisture permeability was measured using a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer having a thickness of 50 μm and prepared by adjusting the coating thickness in the same manner. As a result, the pressure-sensitive adhesive layer had a moisture permeability of 40 g/(m ² ·day).

[Example 1]

On one side of the polarizing film obtained in Production Example 1, a polyvinyl alcohol-based adhesive was applied so that the thickness of the adhesive layer was 0.1 μm (an adhesive layer with a thickness of 50 μm was separately prepared, and the transparency was measured. As a result, the moisture permeability of the adhesive layer was 12 g/(m ² ·day)), and a protective film (cycloolefin film (COP) film (trade name: ZF14-023, thickness: 23 μm, After drying at 80°C for 2 minutes, a polarizing plate with a protective film on one side was produced. On the polarizing film side surface of the obtained polarizing plate with a protective film on one side, the The rubber-based pressure-sensitive adhesive layer 1 obtained in Production Example 3 was used to obtain a polarizing plate.

The obtained polarizing plate was cut out to 110 mm×70 mm, and was bonded to alkali-free glass (Corning, Eagle XG) via a rubber-based adhesive to prepare an evaluation sample.

The obtained evaluation sample was put into an oven with a temperature of 60° C./relative humidity of 90% R.H. for 168 hours, and the amount of deiodination was measured. As a result, the distance at which light leakage occurred was 17 μm relative to the edge, which was considered good.

[Example 2]

An evaluation sample was produced in the same manner as in Example 1.

The obtained evaluation sample was placed in an oven with a temperature of 65°C/relative humidity of 90% R.H. for 168 hours, and the amount of deiodination was measured.

[Example 3]

An evaluation sample was produced in the same manner as in Example 1.

The obtained evaluation sample was placed in an oven with a temperature of 80°C/relative humidity of 90% R.H. for 24 hours, and the amount of deiodination was measured. As a result, the distance at which light leakage occurred was 41 μm relative to the edge, which was good.

[Example 4]

An evaluation sample was produced in the same manner as in Example 1, except that the rubber-based pressure-sensitive adhesive sheet 1 used in Example 1 was changed to the olefin-based pressure-sensitive adhesive sheet produced in Production Example 4.

The obtained evaluation sample was placed in an oven with a temperature of 60°C/relative humidity of 90% R.H. for 168 hr, and the amount of deiodination was measured. As a result, the distance at which light leakage occurred was 18 μm relative to the edge, which was good.

[Example 5]

An evaluation sample was produced in the same manner as in Example 4.

The obtained evaluation sample was put into an oven with a temperature of 65° C./relative humidity of 90% R.H. for 168 hours, and the amount of deiodination was measured. The distance at which light leakage occurred was 52 μm relative to the edge, which was good.

[Example 6]

An evaluation sample was produced in the same manner as in Example 4.

The obtained evaluation sample was put into an oven with a temperature of 80°C/relative humidity of 90% R.H. for 24 hours, and the amount of deiodination was measured. As a result, the distance at which light leakage occurred was 44 μm relative to the edge, which was good.

[Example 7]

An evaluation sample was produced in the same manner as in Example 1, except that the rubber-based PSA sheet 1 used in Example 1 was changed to the rubber-based PSA sheet 2 produced in Production Example 6.

The obtained evaluation sample was placed in an oven with a temperature of 60°C/relative humidity of 90% R.H. for 168 hours, and the amount of deiodination was measured. As a result, the distance at which light leakage occurred was 20 μm relative to the edge, which was good.

[Example 8]

An evaluation sample was produced in the same manner as in Example 7.

The obtained evaluation sample was placed in an oven with a temperature of 65°C/relative humidity of 90% R.H. for 168 hr, and the amount of deiodination was measured. As a result, the distance at which light leakage occurred was 56 μm relative to the edge, which was good.

[Example 9]

An evaluation sample was produced in the same manner as in Example 7.

The obtained evaluation sample was put into an oven at a temperature of 80°C/relative humidity of 90% R.H. for 24 hours, and the amount of deiodination was measured. As a result, the distance at which light leakage occurred was 48 μm relative to the edge, which was good.

[Comparative Example 1]

Except that the rubber-based adhesive 1 used in Example 1 was changed to an acrylic-based adhesive (P-3132, manufactured by Lintec Co., Ltd., thickness 25 μm, moisture permeability at 50 μm thickness: 1030 g/(m ² ·day)) Other than that, it carried out similarly to Example 1, and produced the evaluation sample.

The obtained evaluation sample was put into an oven with a temperature of 60° C./relative humidity of 90% R.H. for 168 hours, and the amount of deiodination was measured. As a result, the distance at which light leakage occurred was 55 μm from the edge.

[Comparative Example 2]

An evaluation sample was produced in the same manner as in Comparative Example 1.

The obtained evaluation sample was put into an oven with a temperature of 65° C./relative humidity of 90% R.H. for 168 hours, and the amount of deiodination was measured. As a result, the distance at which light leakage occurred was 101 μm from the edge.

[Comparative Example 3]

An evaluation sample was produced in the same manner as in Comparative Example 1.

The obtained evaluation sample was put into an oven with a temperature of 80° C./relative humidity of 90% R.H. for 24 hours, and the amount of deiodination was measured. As a result, the distance at which light leakage occurred was 71 μm from the edge.

Industrial Availability

The present invention is useful because it can provide a polarizing plate in which deiodination is suppressed even in a high-temperature and high-humidity environment.

Claims (6)

1. A polarizing plate characterized in that a protective film is laminated on one surface of the polarizing film via an adhesive layer, and the other surface is provided with an adhesive layer, The polarizing film is a film in which iodine is adsorbed on the hydrophilic polymer film, The water vapor transmission rate of the pressure-sensitive adhesive layer and the pressure-sensitive adhesive layer under the conditions of a temperature of 40° C. and a relative humidity of 92% RH were both 100 g/(m ² ·day) or less. 2. The polarizing plate according to claim 1, wherein The pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer formed of a rubber-based pressure-sensitive adhesive composition containing polyisobutylene and a hydrogen abstraction type photopolymerization initiator. 3. polarizing plate according to claim 1, is characterized in that, The pressure-sensitive adhesive layer is an pressure-sensitive adhesive layer containing a polyolefin-based resin. 4. The polarizing plate according to claim 3, wherein The polyolefin-based resin includes an amorphous polypropylene-based resin. 5. The polarizing plate according to any one of claims 1 to 4, wherein The thickness of the polarizing film is 15 μm or less. 6 . An image display device comprising the polarizing plate according to claim 1 .