JP2009237388A - Polarizing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarizing plate having a favorable reworking property, in a polarizing plate comprising a combination of a polarizer and a protective film formed of one of acrylic polymers, alicyclic structure-containing polymers or a polycarbonate. <P>SOLUTION: The polarizing plate includes an adhesive layer between a polarizer and a protective film, wherein the adhesive layer is formed of an adhesive composition that contains a polyvinyl alcohol resin, a urethane resin and a cross-linking agent. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polarizing plate excellent in adhesiveness between a polarizer and a protective film and a method for producing the same.

  In recent years, liquid crystal display devices are often used for in-vehicle use and portable information terminals, and there is a strong demand for reliability of liquid crystal display devices under high temperature and high temperature and high humidity environments. Conventionally, a liquid crystal display device has been used by attaching a polarizing plate on one or both sides of a liquid crystal cell in which liquid crystal is sealed between two electrode substrates on which transparent electrodes are formed. In general, a polarizer prepared by adsorbing iodine or a dichroic dye and stretching and orienting it is bonded to a protective film on both sides.

As a protective film, a protective film mainly composed of a cyclic olefin-based resin may be used for improving moisture permeability and the like. However, adhesion between such a resin and a polarizer is not always sufficient, and there are various types of protective films. Adhesives have been tried.
Patent Document 1 discloses a method in which a polyurethane adhesive is used for adhesion to a protective film made of a thermoplastic saturated norbornene resin. However, a polarizing plate produced using a polyurethane-based adhesive has a problem in reworkability when laminating a liquid crystal panel and a polarizing plate because of insufficient adhesive strength.
JP 2000-32432 A

  An object of the present invention is to provide a polarizer (A) and a protective film (B) in which any material of an acrylic polymer, an alicyclic structure-containing polymer, or a polycarbonate is formed on at least the outermost layer on the polarizer side. An object of the present invention is to provide a polarizing plate having excellent reworkability in a combination polarizing plate.

  As a result of intensive studies to achieve the above object, the present inventor has obtained a polarizer, an acrylic polymer, an alicyclic type by using an adhesive in combination with a polyvinyl alcohol resin, a urethane resin, and a crosslinking agent. As a result of further investigation, we found that workability is improved due to good adhesion and excellent adhesive stability with a protective film on which a film made of either a structural polymer or polycarbonate is formed. It is a thing.

That is, the present invention includes the following aspects.
(1) A polarizing plate having an adhesive layer between the polarizer (A) and the protective film (B),
The film on the polarizer (A) side of the protective film (B) is made of an acrylic polymer, an alicyclic structure-containing polymer, or a polycarbonate,
A polarizing plate, wherein the adhesive layer is formed of an adhesive composition containing a polyvinyl alcohol resin, a urethane resin, and a crosslinking agent.
(2) The polarizing plate according to (1), wherein the polyvinyl alcohol resin is a modified polyvinyl alcohol resin.
(3) The polarizing plate according to any one of (1) to (2), wherein the protective film (B) is a stretched film.
(4) The polarizing plate according to any one of (1) to (3), wherein the crosslinking agent is selected from the group consisting of an aqueous epoxy compound, an aqueous amino compound, an aqueous isocyanate compound, an aqueous carbodiimide compound, and an aqueous aldehyde compound.

(5) A step of applying an aqueous dispersion containing a polyvinyl alcohol resin, a urethane resin, and a crosslinking agent on the polarizer (A) and / or the protective film (B),
Bonding the polarizer (A) and the protective film (B);
The manufacturing method of the polarizing plate in any one of (1)-(4) characterized by including.
(6) On the polarizer (A) and / or the protective film (B), the viscosity of the aqueous dispersion to be applied is
The production method of (5), which is 20 mPa · s or less.
(7) Before the step of applying the aqueous dispersion on the polarizer (A) and / or the protective film (B),
The manufacturing method as described in (5) or (6) characterized by including the process of surface-treating a protective film (B).

  In a polarizing plate including a protective film in which a film made of any of a polarizer and an acrylic polymer, an alicyclic structure polymer, or a polycarbonate is laminated, a polarizing plate having excellent adhesiveness and reworkability can be provided.

(1) Polarizer The polarizer used in the present invention is not particularly limited, and various types can be used. Examples of the polarizer include hydrophilic polymer films such as polyvinyl alcohol film, partially formalized polyvinyl alcohol film, and ethylene / vinyl acetate copolymer partially saponified film, and two colors such as iodine and dichroic dye. And polyene-based oriented films such as those obtained by adsorbing a functional material and uniaxially stretched, polyvinyl alcohol dehydrated products, and polyvinyl chloride dehydrochlorinated products. Among these, a polarizer made of a dichroic substance such as a polyvinyl alcohol film and iodine or a dichroic dye is preferable.

(2) Protective film The average thickness of the protective film used by this invention is 5 micrometers-1 mm normally, Preferably it is 20-200 micrometers. If the thickness of the protective film is too thick or too thin, the processability deteriorates, which is not preferable. The protective film is preferably transparent and has a light transmittance in the visible region of 400 to 700 nm of 80% or more and is smooth.
The protective film includes (a) an acrylic polymer, an alicyclic structure-containing polymer, and a single layer film made of a resin selected from polycarbonate, (b) an acrylic polymer, an alicyclic structure-containing polymer, and a polycarbonate. A multilayer film in which a layer made of a resin selected from the above is formed on at least one outermost surface can be used. In addition, when laminating | stacking on the outermost surface of only one side, the surface becomes a polarizer side.

(A) Single layer film The average thickness of a single layer film is 5 micrometers-1 mm normally, Preferably it is 20-200 micrometers. If the thickness of the single layer film is too thick or too thin, the processability is deteriorated, which is not preferable. Of these, alicyclic structure-containing polymers are preferred from the viewpoint of processability.

  The alicyclic structure-containing polymer suitably used in the present invention is a polymer having a cycloalkane structure in the main chain and / or side chain. From the viewpoint of mechanical strength and heat resistance, a polymer containing a cycloalkane structure in the main chain is preferred. In addition, examples of the cycloalkane structure include monocyclic rings and polycyclic rings (fused polycyclic rings, bridged rings, etc.). The number of carbon atoms constituting one unit of the cycloalkane structure is not particularly limited, but is usually 4 to 30, preferably 5 to 20, more preferably 5 to 15 when the resin film is used. The mechanical strength, heat resistance, and moldability of these are highly balanced and suitable. The alicyclic structure-containing polymer used in the present invention is usually a thermoplastic resin.

  In the alicyclic structure-containing polymer, the repeating unit having a cycloalkane structure is usually 30 to 100% by weight, preferably 50 to 100% by weight, based on all repeating units in the main chain of the alicyclic structure-containing polymer. More preferably, it has 70 to 100 weight%. If the ratio of the repeating unit having a cycloalkane structure is within these ranges, the heat resistance of the resin film is excellent.

  The alicyclic structure-containing polymer is usually obtained by addition polymerization or ring-opening polymerization of an olefin having a ring structure, and hydrogenating an unsaturated bond part and an aromatic ring part as necessary.

Examples of the olefin having a ring structure used for obtaining the alicyclic structure-containing polymer include norbornene, dicyclopentadiene, tetracyclododecene, ethyltetracyclododecene, ethylidenetetracyclododecene, and tetracyclo [7.4. .0.1 ^10,13 . 0 ^2,7 ] polycyclic unsaturated hydrocarbons such as trideca-2,4,6,11-tetraene and derivatives thereof; cyclobutene, cyclopentene, cyclohexene, 3,4-dimethylcyclopentene, 3-methylcyclohexene, 2- Unsaturated hydrocarbons having a monocyclic structure such as (2-methylbutyl) -1-cyclohexene, cyclooctene, 3a, 5,6,7a-tetrahydro-4,7-methano-1H-indene, cycloheptene, cyclopentadiene, cyclohexadiene And derivatives thereof; aromatic vinyl compounds such as styrene, α-methylstyrene, and divinylbenzene; and alicyclic vinyl compounds such as vinylcyclohexane, vinylcyclohexene, vinylcyclopentane, and vinylcyclopentene. The olefins having a ring structure can be used alone or in combination of two or more.

A monomer copolymerizable with an olefin having a ring structure can be subjected to addition copolymerization, if necessary. Specific examples thereof include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1 -Pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1-octene 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene, etc., ethylene or α-olefin having 2 to 20 carbon atoms; 1,4-hexadiene, 4-methyl-1, Non-conjugated dienes such as 4-hexadiene, 5-methyl-1,4-hexadiene and 1,7-octadiene; conjugated dienes such as 1,3-butadiene and isoprene It is. These monomers can be used alone or in combination of two or more.

  Polymerization of an olefin having a ring structure can be carried out according to a known method. The polymerization temperature, pressure and the like are not particularly limited, but the polymerization is usually performed at a polymerization temperature of -50 ° C to 100 ° C and a polymerization pressure of 0 to 5 MPa. The hydrogenation reaction is performed by blowing hydrogen in the presence of a known hydrogenation catalyst.

  Specific examples of the alicyclic structure-containing polymer include a ring-opening polymer of a norbornene monomer and a hydride thereof, an addition polymer of a norbornene monomer and a hydride thereof, a norbornene monomer and a vinyl compound (Ethylene, α-olefin, etc.) addition polymer and hydride thereof, monocyclic cycloalkene polymer and hydride thereof, alicyclic conjugated diene monomer polymer and hydride thereof, vinyl fat Examples thereof include polymers of cyclic hydrocarbon monomers and hydrogenated products thereof, and products obtained by hydrogenating aromatic rings of polymers of aromatic vinyl compounds. Among these, hydrides of ring-opening polymers of norbornene monomers, addition polymers of norbornene monomers, addition polymers of norbornene monomers and vinyl compounds (= ethylene, α-olefins, etc.) An aromatic ring hydride of an aromatic olefin polymer is preferable, and a hydride of a ring-opening polymer of a norbornene monomer is particularly preferable. The said alicyclic structure containing polymer can be used individually or in combination of 2 types or more, respectively.

  As the alicyclic structure-containing resin, for example, the product names “ZEONOR” and “ZEONEX” are marketed by ZEON Corporation, the product name “ARTON” by JSR Corporation, and the product name “APEL” by Mitsui Petrochemical Co., Ltd. ing.

  Examples of the acrylic polymer used in the present invention include homopolymers of (meth) acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate; alkyl group hydrogen is OH group, COOH Homopolymer of (meth) acrylic acid alkyl ester substituted by a functional group such as a group or NH2 group; or (meth) acrylic acid alkyl ester and styrene, vinyl acetate, α, β-monoethylenically unsaturated carboxylic acid , Vinyl toluene, and a copolymer with a vinyl monomer having an unsaturated bond such as α-methylstyrene. As a thermoplastic acrylic polymer, only 1 type may be used among these and it may use it in combination of 2 or more type. More preferably, the thermoplastic acrylic polymer contains polymethyl methacrylate and polybutyl methacrylate as monomer units.

  The polycarbonate used in the present invention is a polyester of carbonic acid and glycol or dihydric phenol, and usually contains carbonic acid and 2,2′-bis (4-hydroxyphenyl) -propane (commonly called bisphenol-A) as a structural unit. There are various aromatic polycarbonates. In the present invention, the present invention is not limited to this. For example, 1,1-bis (4-hydroxyphenyl) -alkylcycloalkane, 1,1-bis (3-substituted-4-hydroxyphenyl) -alkylcycloalkane, 1-bis (3,5-substituted-4-hydroxyphenyl) -alkylcycloalkane and 9,9-bis (4-hydroxyphenyl) fluorenes as monomers A copolymer polycarbonate, a homopolymer, a mixture with a polycarbonate having phenol-A as a monomer component, and a copolymer polycarbonate having the above dihydric phenol and bisphenol-A as monomer components can be used.

  Specific examples of 1,1-bis (4-hydroxyphenyl) -alkylcycloalkane include 1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,1-bis (4-hydroxyphenyl) ) -3,3-dimethyl-5,5-dimethylcyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3-dimethyl-5-methylcyclopentane and the like.

  1,1-bis (3-substituted-4-hydroxyphenyl) -alkylcycloalkane includes 1,1-bis (4-hydroxyphenyl) -alkyl substituted with an alkyl group having 1 to 12 carbon atoms or a halogen group. Cycloalkanes such as 1,1-bis (3-methyl-4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,1-bis (3-ethyl-4-hydroxyphenyl) -3,3- Dimethyl-5,5-dimethylcyclohexane, 1,1-bis (3-chloro-4-hydroxyphenyl) -3,3-dimethyl-4-methylcyclohexane, 1,1-bis (3-bromo-4-hydroxyphenyl) ) -3,3-dimethyl-5-methylcyclopentane.

  1,1-bis (3,5-substituted-4-hydroxyphenyl) -alkylcycloalkane includes 1,1-bis (4-hydroxyphenyl) substituted with an alkyl group having 1 to 12 carbon atoms or a halogen group. Alkylcycloalkanes such as 1,1-bis (3-methyl-4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,1-bis (3,5-dichloro-4-hydroxyphenyl)- 3,3-dimethyl-5-methylcyclohexane, 1,1-bis (3-ethyl-5-methyl-4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,1-bis (3,5- Dimethyl-4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) -3,3-di Chill -5-methyl cyclopentane, and the like.

  Examples of 9,9-bis (4-hydroxyphenyl) fluorenes include 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (3-methyl-4-hydroxyphenyl) fluorene, Examples include 9-bis (3-ethyl-4-hydroxyphenyl) fluorene.

  Furthermore, as other bisphenol components, 2,2′-bis (4-hydroxyphenyl) propane (bisphenol-A), 4,4 ′-(α-methylbenzylidene) bisphenol, bis (4-hydroxyphenyl) methane, 2 , 2′-bis (4-hydroxyphenyl) butane, 3,3′-bis (4-hydroxyphenyl) pentane, 4,4′-bis (4-hydroxyphenyl) hebutane, 4,4′-bis (4- Hydroxyphenyl) 2,5-dimethylhebutane, bis (4-hydroxyphenyl) methylphenylmethane, bis (4-hydroxyphenyl) diphenylmethane, 2,2′-bis (4-hydroxyphenyl) octane, bis (4-hydroxy) Phenyl) octane, bis (4-hydroxyphenyl) 4-fluorophenylmethane, 2, '-Bis (3-fluoro-4-hydroxyphenyl) propane, bis (3,5-dimethyl-4hydroxyphenyl) methane, 2,2'-bis (3,5-dimethyl-4-hydroxyphenyl) propane, bis ( 3,5-dimethyl-4-hydroxyphenyl) phenylethane, bis (3-methyl-4-hydroxyphenyl) diphenylmethane and the like. These can be used alone or in admixture of two or more.

  In addition to the bisphenol component, the polycarbonate contains a polyester carbonate using a small amount of aliphatic or aromatic dicarboxylic acid as a comonomer of the acid component. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, p-xylene glycol, bis (4-hydroxyphenyl) -methane, 1,1′-bis (4-hydroxyphenyl) -ethane, and 1,1′-. Bis (4-hydroxyphenyl) -butane, 2,2′-bis (4-hydroxyphenyl) -butane and the like can be mentioned. Of these, terephthalic acid and isophthalic acid are preferred.

The resin used in the present invention is not particularly limited by its molecular weight. The molecular weight of the resin is measured by gel permeation chromatography (GPC) using cyclohexane or toluene as a solvent. The weight average molecular weight in terms of polystyrene (when the solvent is toluene) or polyisoprene (when the solvent is cyclohexane) ( Mw), usually in the range of 1,000 to 1,000,000, preferably 5,000 to 500,000, more preferably 10,000 to 250,000. When the weight average molecular weight (Mw) of the resin is within this range, heat resistance, adhesiveness, surface smoothness and the like are balanced, which is preferable.
The molecular weight distribution of the resin is a ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by GPC, and is usually 5 or less, preferably 4 or less, more preferably 3 or less. .

The glass transition temperature of the resin used in the present invention is preferably 60 to 200 ° C, more preferably 100 to 180 ° C. The glass transition temperature can be measured by differential scanning calorimetry (DSC). Resins used in the present invention are compounding agents such as colorants such as pigments and dyes, optical brighteners, dispersants, heat stabilizers, light stabilizers, ultraviolet absorbers, antistatic agents, antioxidants, lubricants, and solvents. May be appropriately blended.
The resin used in the present invention is a colorant such as a pigment or dye, a fluorescent brightener, a dispersant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, an antistatic agent, an antioxidant, a lubricant, a solvent, etc. The compounding agent may be appropriately blended.

There is no restriction | limiting in particular in the shaping | molding method of the single layer film used for this invention, For example, normal shaping | molding methods, such as a heat-melt shaping | molding method and a solution casting method, are employable. Among these, a heat-melt molding method that can reduce volatile components in the molded body is preferable.
The heat melt molding method includes a melt extrusion molding method, a press molding method, an inflation method, an injection molding method, a blow molding method, a stretch molding method, etc., among them, in order to obtain a film having excellent mechanical strength and surface accuracy. Is preferably a melt extrusion method.

(B) Multilayer film The multilayer film used in the present invention is a multilayer film in which a layer made of a resin selected from the acrylic polymer, alicyclic structure-containing polymer, and polycarbonate is formed on at least one outermost surface. is there.

  The average thickness of the multilayer film used for this invention is 5 micrometers-1 mm normally, Preferably it is 20-200 micrometers. If the thickness of the multilayer film is too thick or too thin, the processability deteriorates, which is not preferable. Among these, as the resin of the layer formed on the outermost surface, an alicyclic structure-containing polymer is preferable from the viewpoint of processability.

The resin used for the intermediate layer of the multilayer film used in the present invention is not particularly limited as long as it is transparent. For example, polycarbonate resin, polyether sulfone resin, polyethylene terephthalate resin, polyimide resin, polymethyl methacrylate resin, polysulfone resin, Examples include polyarylate resin, polyethylene resin, polyvinyl chloride resin, cellulose diacetate, cellulose triacetate, acrylic resin, and alicyclic structure polymer.
The resin used for the intermediate layer of the multilayer film used in the present invention is a colorant such as a pigment or dye, a fluorescent brightener, a dispersant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, an antistatic agent, an antioxidant. A compounding agent such as an agent, a lubricant, and a solvent may be appropriately blended.
As resin used for the outermost surface of the multilayer film used for this invention, resin illustrated by the single layer film can be used.
The method for forming the multilayer film used in the present invention is not particularly limited, for example, a coextrusion molding method such as a coextrusion T-die method, a coextrusion inflation method, a coextrusion lamination method, a film lamination molding method such as dry lamination, and the like. A known method such as a coating molding method in which a base resin film is coated with a resin solution can be appropriately used. Among these, from the viewpoint of production efficiency and the like, a molding method by coextrusion is preferable.

As the protective film used in the present invention, a single layer film or a film obtained by stretching the multilayer film can be used.
There is no restriction | limiting in particular in the method of extending | stretching a single layer film or a multilayer film, A conventionally well-known method may be applied. Specifically, a uniaxial stretching method such as a method of uniaxial stretching in the longitudinal direction using the difference in peripheral speed on the roll side, a method of uniaxial stretching in the lateral direction using a tenter, etc .; At the same time as stretching in the longitudinal direction, use the simultaneous biaxial stretching method that stretches in the transverse direction according to the spread angle of the guide rail or the longitudinal direction using the difference in peripheral speed between the rolls, and then grip the both ends of the clip And a biaxial stretching method such as a sequential biaxial stretching method of stretching in the transverse direction using a tenter.

Although the stretching temperature is not particularly limited, the glass transition temperature Tg of the resin constituting the film is preferably in the range of (Tg-10) (° C) to (Tg + 20) (° C), and (Tg-5) (° C). The range of-(Tg + 15) (degreeC) is more preferable. In the case of a multilayer film, it is preferable to consider based on the glass transition temperature of the resin constituting the thickest layer.
Here, the draw ratio is usually 1.1 to 30 times, preferably 1.3 to 10 times. If the draw ratio is out of the above range, the orientation may be insufficient, the refractive index anisotropy, and thus the retardation may be insufficiently developed, or the film may be broken.

  The protective film used in the present invention is preferably subjected to a surface treatment before being bonded to the polarizer. Examples of the surface treatment include alkali treatment, corona discharge treatment, ultraviolet irradiation treatment, and the like. Preferably, the contact state of water droplets on the film surface is preferably 50 ° or less, more preferably 40 ° or less.

(3) Adhesive Layer The adhesive layer used in the present invention is formed of an adhesive composition containing (a) a polyvinyl alcohol resin, (b) a urethane resin, and (c) a crosslinking agent. Polyvinyl alcohol resin refers to polyvinyl alcohol and polyvinyl alcohol derivatives.

(A) Polyvinyl alcohol resin The polyvinyl alcohol resin to be used is not particularly limited, but polyvinyl alcohol obtained by saponifying polyvinyl acetate; a derivative thereof; and a monomer having copolymerizability with vinyl acetate. Saponified products of copolymers with monomers; modified polyvinyl alcohol obtained by acetalizing, etherifying, grafting, phosphoric esterifying, etc. of polyvinyl alcohol. Examples of the monomer include unsaturated carboxylic acids such as (anhydrous) maleic acid, fumaric acid, crotonic acid, itaconic acid, (meth) acrylic acid, and esters thereof; α-olefins such as ethylene and propylene, (meth) Examples include allyl sulfonic acid (soda), sulfonic acid soda (monoalkyl malate), disulfonic acid soda alkyl maleate, N-methylol acrylamide, acrylamide alkyl sulfonic acid alkali salt, N-vinyl pyrrolidone, N-vinyl pyrrolidone derivatives and the like. . Among these, the polyvinyl alcohol resin which has an acetoacetyl group is preferable at the point of adhesive force. These polyvinyl alcohol resins can be used alone or in combination of two or more.

    The polyvinyl alcohol resin is not particularly limited, but from the viewpoint of adhesiveness, the average degree of polymerization is about 100 to 3000, preferably 500 to 3000, the average saponification degree is about 85 to 100 mol%, preferably 90 to 100 mol%. is there.

    A polyvinyl alcohol resin containing an acetoacetyl group is obtained by reacting a polyvinyl alcohol resin and diketene by a known method. For example, a method in which a polyvinyl alcohol-based resin is dispersed in a solvent such as acetic acid and diketene is added thereto. A polyvinyl alcohol resin is previously dissolved in a solvent such as dimethylformamide or dioxane, and diketene is added thereto. Methods and the like. Another example is a method in which diketene gas or liquid diketene is brought into direct contact with polyvinyl alcohol.

    The degree of acetoacetyl group modification of the polyvinyl alcohol resin containing an acetoacetyl group is not particularly limited as long as it is 0.1 mol% or more. If it is less than 0.1 mol%, the water resistance of the adhesive layer is insufficient and unsuitable. The degree of acetoacetyl group modification is preferably about 0.1 to 40 mol%, more preferably 1 to 20 mol%, and particularly preferably 2 to 7 mol%. The degree of acetoacetyl modification is a value measured by NMR.

(B) Urethane resin The urethane resin of the present invention is not particularly limited. For example, (i) a component containing an average of two or more active hydrogens in one molecule and (ii) a polyvalent isocyanate component The urethane polymer obtained by reacting or the above components (i) and (ii) are urethanated in an organic solvent that is inert to the reaction and has a high affinity for water under the condition of excess isocyanate group. It is produced by forming an isocyanate group-containing prepolymer, then neutralizing the prepolymer, chain-extending with a chain extender, and adding water to obtain an aqueous dispersion. These urethane polymers may contain an acid component (acid residue).

  The chain extension method of the isocyanate group-containing prepolymer may be a known method. For example, water, a water-soluble polyamine, glycols or the like is used as the chain extender, and the isocyanate group-containing prepolymer and the chain extender component are used. May be reacted in the presence of a catalyst as necessary.

The component containing an average of 2 or more active hydrogens in one molecule of the component (i) is not particularly limited, but preferably has a hydroxylic active hydrogen. Specific examples of such compounds include the following.
(1) Diol compound: ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1,4-butylene glycol, 1,5- Pentanediol, neopentyl glycol, 1,6-hexane glycol, 2,5-hexanediol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, tricyclodecane dimethanol, 1,4- Cyclohexanedimethanol and the like.

  (2) Polyether diols: alkylene oxide adducts of the above diol compounds, ring-opening (co) polymers of alkylene oxides and cyclic ethers (tetrahydrofuran, etc.) such as polyethylene glycol, polypropylene glycol, ethylene glycol-propylene glycol (block) Or random) copolymer, glycol, polytetramethylene glycol, polyhexamethylene glycol, polyoctamethylene glycol, and the like.

  (3) Polyester diol: Dicarboxylic acid (anhydride) such as adipic acid, succinic acid, sebacic acid, glutaric acid, maleic acid, fumaric acid, phthalic acid, and ethylene glycol, propylene glycol as mentioned in (1) above , 1,4-butanediol, 1,6-hexanediol, 1,8-octamethylenediol, neopentylglycol and other diol compounds obtained by polycondensation under hydroxyl group-excess conditions. Specifically, ethylene glycol-adipic acid condensate, butanediol-adipine condensate, hexamethylene glycol-adipic acid condensate, ethylene glycol-propylene glycol-adipic acid condensate, or lactone is opened using glycol as an initiator. Examples thereof include polymerized polylactone diol.

  (4) Polyether ester diol: (anhydrous) dicarboxylic acid as exemplified in the above (3), an ether group-containing diol (polyether diol or diethylene glycol of (2) above) or a mixture of this with another glycol And a product obtained by reacting an alkylene oxide in addition to, for example, a polytetramethylene glycol-adipic acid condensate.

  (5) Polycarbonate diol: General formula HO-R- (OC (O) -O-R) x-OH (wherein R is a saturated fatty acid diol residue having 1 to 12 carbon atoms, x is a molecular The compound etc. which show the number of repeating units and are the integers of 5-50 normally.). These include a transesterification method in which a saturated aliphatic diol and a substituted carbonate (diethyl carbonate, diphenyl carbonate, etc.) are reacted under the condition that the hydroxyl group is excessive, the saturated aliphatic diol and phosgene are reacted, or as necessary. Then, it can be obtained by a method of further reacting with a saturated aliphatic diol.

The compounds as exemplified in the above (1) to (5) can be used alone or in combination of two or more.
As the polyisocyanate component (ii) to be reacted with the component (i), an aliphatic, alicyclic or aromatic compound containing an average of two or more isocyanate groups in one molecule can be used.

  The aliphatic diisocyanate compound is preferably an aliphatic diisocyanate having 1 to 12 carbon atoms, and examples thereof include hexamethylene diisocyanate and 2,2,4-trimethylhexane diisocyanate. The alicyclic diisocyanate compound is preferably an alicyclic diisocyanate having 4 to 18 carbon atoms, and examples thereof include 1,4-cyclohexane diisocyanate and methylcyclohexylene diisocyanate. Examples of the aromatic isocyanate include tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate.

In addition, those containing acid residues in the urethane-based polymer can be dispersed in water without using a surfactant or in a small amount, so that the water resistance of the coating film is improved. There is expected. The content of the acid residue is preferably in the range of 25 to 150 (mgKOH / g), preferably 30 to 100 (mgKOH / g) as the acid value of the urethane polymer. If the acid value is less than 25, the water dispersibility tends to be insufficient, and it is often necessary to use a surfactant. On the other hand, if the acid value is more than 150, the water resistance of the coating film tends to be poor.

  As a method for introducing an acid group into a urethane polymer, a conventionally used method can be used without any particular limitation. For example, dimethylolalkanoic acid is one of the glycol components described in (2) to (4) above. A method of introducing an acid group by introducing a carboxyl group into a polyether diol, a polyester diol, a polyether ester diol or the like in advance by substituting a part or all of them is preferable. Examples of the dimethylolalkanoic acid used here include dimethylolacetic acid, dimethylolpropionic acid, and dimethylolbutyric acid.

Moreover, since the dispersibility of a urethane resin can be improved by neutralizing the acid component which remains in a urethane type polymer, it is preferable to neutralize. Examples of the neutralizing agent that neutralizes the acid component include organic amines such as trimethylamine, triethylamine, tripropylamine, tributylamine, N-methyldiethanolamine, and triethanolamine, and inorganic such as sodium hydroxide, potassium hydroxide, and ammonia. A base etc. can be mentioned.

The urethane resin of the present invention preferably has a number average molecular weight of 1,000 or more, more preferably 20,000 or more. However, it is preferably 1,000,000 or less, more preferably 200,000 or less.
The particle size of the urethane resin particles in the aqueous dispersion of the present invention is preferably 0.01 μm to 0.5 μm. Moreover, it is preferable that resin solid content is 15 to 70 weight%. The liquid viscosity is preferably 1 to 10,000 mPa · s.

As the urethane resin, commercially available water-based urethane resins can be used as they are. For example, “Adekabon titer” series manufactured by Asahi Denka Kogyo Co., Ltd., “Ole” manufactured by Mitsui Toatsu Chemical Co., Ltd. "Star" series, "Bondic" series by Dainippon Ink & Chemicals, Ltd., "Hydran" series, "Imprunil" series by Bayer, "Sofuranate" series by Soflan Japan, Kao Corporation "Poise" series manufactured by Sanyo Chemical Industry Co., Ltd., "Samprene" series manufactured by Sanyo Chemical Industry Co., Ltd., "Izelux" series manufactured by Hodogaya Chemical Co., Ltd., "Superflex" series manufactured by Daiichi Kogyo Seiyaku Co., Ltd., The “Neoletz” series manufactured by Zeneca Corporation can be used.

  The mixing ratio of the polyvinyl alcohol resin and the urethane resin is not particularly limited, but the weight ratio of the polyvinyl alcohol resin and the urethane resin is preferably 4:96 to 96: 4.

(C) Crosslinking agent The crosslinking agent used in the present invention is not particularly limited as long as it can form an adhesive layer excellent in reworkability, but is based on an aqueous epoxy compound, an aqueous amino compound, an aqueous isocyanate compound, an aqueous carbodiimide. Those selected from either a compound or an aqueous aldehyde compound are preferred. These crosslinking agents may be used alone or in combination.

The water-based epoxy compound may be any compound that is soluble in water or has two or more epoxy groups emulsified. For example,
Etherification of 1 mol of glycols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexane glycol, neopentyl glycol and 2 mol of epichlorohydrin Diepoxy compounds obtained by:
A polyepoxy compound obtained by etherification of 1 mol of polyhydric alcohols such as glycerin, polyglycerin, trimethylolpropane, pentaerythritol, sorbitol and 2 mol or more of epichlorohydrin;
And epoxy compounds such as diepoxy compounds obtained by esterification of 1 mol of dicarboxylic acid such as phthalic acid, terephthalic acid, oxalic acid and adipic acid and 2 mol of epichlorohydrin.

The aqueous amino compound may be any compound that is soluble in water or has two or more amino groups emulsified. For example, carbodihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, acrylic acid dihydrazide, etc. A compound, a melamine resin, a urea resin, a guanamine resin, etc. are mentioned.

The water-based isocyanate compound may be a compound that has solubility in water or has two or more non-blocked isocyanate groups and block-type isocyanate groups emulsified. Examples of the non-blocking isocyanate compound include compounds obtained by reacting a polyfunctional isocyanate compound with a monovalent or polyvalent nonionic polyalkylene ether alcohol. As the block type isocyanate compound, 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), 4,4′-diphenylmethane diisocyanate (MDI), xylylene diene Isocyanate (XDI), isophorone diisocyanate (IPDI), methylcyclohexyl diisocyanate (H6TDI), 4,4'-dicyclohexylmethane diisocyanate (H12MDI), 1,3-bis (isocyanatomethyl) cyclohexane (H6XDI), tetramethylxylylene diisocyanate (TMXDI), 2,2,4-trimethylhexamethylene diisocyanate (TMHDI), hexamethylene diisocyanate (HDI), norbornene diisocyanate (NBDI), 2, 4,6-triisopropylphenyl diisocyanate (TIDI), 1,12-diisocyanatododecane (DDI), 2,4, -bis- (8-isocyanatooctyl) -1,3-dioctylcyclobutane (OCDI), n-pentane- 1,4-diisocyanates and their isocyanurate-modified products, adduct-modified products, burette-modified products, allophanate-modified products, and polymers having one or more isocyanate groups are modified with polyoxyalkylene groups, carboxyl groups, etc. And a compound obtained by making it water-soluble and / or water-dispersible and masking an isocyanate group with a blocking agent (phenol, ε-caprolactam, etc.).

The water-based carbodiimide compound may be a compound compound that is soluble in water or has two or more carbodiimide bonds (—N═C═N—) emulsified. A compound having two or more carbodiimide bonds is obtained by a method in which two isocyanate groups are decarboxylated to form -N = C = N- using two or more molecules of polyisocyanate and a carbodiimidization catalyst. be able to. The polyisocyanate and the carbodiimidization catalyst used when producing a compound having two or more carbodiimide bonds are not particularly limited, and conventionally known ones can be used.

Examples of the compound having an aldehyde group include monoaldehydes such as formaldehyde, acetaldehyde, propionaldehyde, crotonaldehyde, benzaldehyde and formaldehyde, dialdehydes such as glyoxal, malondialdehyde, glutaraldehyde and terephthalaldehyde, dialdehyde starch and acrolein. Examples include copolymer acrylic resins.

The ratio of the crosslinking agent is 1 to 30 parts by weight, preferably 5 to 15 parts by weight (solid content) of 100 parts by weight (solid content) of the polyvinyl alcohol resin and urethane resin. Is preferred. By setting it as the said mixing | blending, the intensity | strength of a coating film can be improved and the outstanding adhesive force can be provided.

When adjusting an adhesive agent, it adjusts by mixing the aqueous dispersion of resin and a crosslinking agent until it becomes uniform. Here, the aqueous dispersion means a resin or a crosslinking agent partially dissolved in water or in an emulsion state. Any temperature, stirring method, time, and the like can be selected as long as the function of the adhesive is not lost.
The adhesive used in the present invention is a combination of a colorant such as a pigment or dye, a fluorescent brightener, a dispersant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, an antistatic agent, an antioxidant, or a lubricant. An agent may be appropriately blended.

(Applying adhesive)
Application | coating of the said adhesive agent may be performed to any of a transparent protective film and a polarizer, and may be performed to both. It is preferable that the thickness of the adhesive layer is about 0.05 to 5 μm.
The application operation is not particularly limited, and various means such as a roll method, a spray method, and an immersion method can be employed. The method for laminating the film after application is not particularly limited. For example, a method in which a transparent protective film and a polarizer are continuously passed between a pair of rolls through an adhesive layer can be used.
Furthermore, it is desirable to dry the bonded polarizing plate. The drying temperature can be selected in a range that does not impair the function as a polarizing plate and does not cause a problem in the actual production process, and is preferably 10 to 150 ° C, more preferably 20 to 120 ° C, and further preferably 30 to 100. ° C. The drying time can be appropriately selected according to the drying temperature, but is in the range of 10 seconds to several hours in consideration of the actual manufacturing process.

(Peel strength)
The peel strength is measured by a surface-interface cutting method (SAICAS method). The peel strength by the SAICAS method (Surface And Interfacial Cutting Analysis System) is due to interfacial cutting of the coating film with a cutting blade sold by Dainippon Plastics, Daipura Wintes, Mekong, Mitsuwa Riken, etc. The resistance force received by the cutting blade is detected by pressure, and is measured by a coating film adhesion strength measuring machine (Cycus; trade name) that measures the adhesion strength of the coating film according to the magnitude of the detected pressure. Specifically, the evaluation is performed by the method described in the examples.

  In the present invention, a preferable peel strength is 0.1 kN / m or more, and more preferably 0.14 kN / m.

The invention is explained in more detail by means of examples. In addition, this invention is not limited to an Example. Evaluation in the present invention was performed according to the following method.

(Viscosity measurement)
The viscosity at 20 ° C. was measured for the produced aqueous adhesive using a tuning fork type vibration viscometer SV-10 (manufactured by A & D).

(Peel strength measurement)
The produced polarizing plate was cut out into 5 * 20 mm, it affixed on the glass plate so that a polarizer surface might contact | connect a glass plate using Aron Alpha 201 (made by Toagosei), and it was set as the sample for a measurement. The peel strength was evaluated by the surface-interface cutting method (SAICAS method) using the sample. The measurement was performed with a Cycus CN-20 model manufactured by Daipura Wintes Co., Ltd. using a single crystal diamond having a cutting edge width of 0.8 mm and a rake angle of 40 ° and a relief angle of 10 °. Measurement was performed by cutting at a horizontal speed of 2 μm / second and a vertical speed of 1 μm / second. When the cutting edge was cut to the interface between the transparent protective film and the polarizer, the vertical velocity was 0 μm / min, the cutting edge was moved in parallel with the substrate, and the parallel force FH [kN] was measured. From the width w [m] of the cutting edge, the peel strength P was obtained from the calculation formula of P [kN / m] = FH [kN] / w [m].

Production Example 1
<Manufacture of water-based urethane resin>
A 2000 ml four-necked flask equipped with a thermometer, stirrer, nitrogen inlet tube, and condenser tube was charged with 317.2 g of 3-methyl-1,5-pentanediol, 174 g of terephthalic acid, and 146 g of adipic acid in a reactor. The esterification reaction was carried out while distilling off the water produced at 200 ° C. while passing nitrogen gas under pressure. When the acid value of the polyester reached 1.0 mgKOH / g, the degree of vacuum was gradually increased by a vacuum pump to complete the reaction. The obtained polyester polyol had a hydroxyl value of 56.1 mgKOH / g, an acid value of 0.2 mgKOH / g, and a number average molecular weight (calculated from the hydroxyl value) of 2000.
In a 2000 ml four-necked flask equipped with a thermometer, a stirrer, a nitrogen introduction tube, and a cooling tube, 840 g of the polyester polyol, 119 g of tolylene diisocyanate, and 200 g of methyl ethyl ketone were added and reacted at 75 ° C. for 1 hour while introducing nitrogen. . After completion of the reaction, the mixture was cooled to 60 ° C., 41 g of dimethylolpropionic acid and 25 g of triethylamine were added and reacted at 75 ° C. to obtain a prepolymer solution. Next, this prepolymer was cooled to 40 ° C., 1500 parts of water was added, and emulsification was performed by stirring at high speed with a homomixer. Methyl ethyl ketone was distilled off from this emulsion by heating under reduced pressure to obtain an aqueous polyurethane resin solution having a solid content of 40%.

Production Example 2
<Manufacture of Transparent Protective Film 1> 10 g of a multilayer film acrylic resin (parapet, manufactured by Kuraray) whose surface is made of an acrylic resin was dissolved in 40 g of butyl acetate to prepare an acrylic resin coating solution. Next, an acrylic resin coating solution is applied to the easy adhesion surface of a 100 μm thick PET film (A4100, manufactured by Toyobo Co., Ltd.) so that the acrylic resin layer after drying has a thickness of 2 μm, and dried at 60 ° C. for 20 minutes. Thereby, the multilayer film (transparent protective film 1) which the surface consists of an acrylic resin was produced.

Production Example 3
<Manufacture of Transparent Protective Film 2> 10 g of a multilayer film polycarbonate (Panlite C-1400QJ, manufactured by Teijin Chemicals) whose surface is made of polycarbonate was dissolved in 40 g of methylene chloride to prepare a 20% by weight polycarbonate coating solution. By applying a polycarbonate coating solution on the easy-adhesive surface of a 100 μm thick PET film (A4100, manufactured by Toyobo Co., Ltd.) so that the thickness of the polycarbonate layer after drying is 2 μm, and drying at 40 ° C. for 30 minutes, Produced a multilayer film (transparent protective film 2) made of polycarbonate.

Production Example 4
<Manufacture of transparent protective film 3> After drying pellets of ZEONOR1420 (manufactured by ZEON), which is a biaxially stretched ZNR film norbornene-based resin, at 100 ° C for 5 hours, the pellets are supplied to an extruder by a conventional method to 250 ° C And was discharged from a die onto a cooling drum to obtain an unstretched film having a thickness of 150 μm. Next, the unstretched film produced in Production Example 4 was stretched 1.2 times in the longitudinal direction at a temperature of 143 ° C. by a longitudinal stretching machine using a float system between rolls, and this was further processed by a tenter method. A biaxially stretched film with a thickness of 70 μm (transparent protection) is stretched 1.8 times in the lateral direction at a temperature of 150 ° C. while adjusting the take-up tension and the tenter chain tension. Film 3) was obtained.

Example 1
(Preparation of polarizer)
A polyvinyl alcohol film having a thickness of 80 μm is dyed in a 0.3% iodine aqueous solution, stretched up to 5 times in a 4% boric acid aqueous solution and a 2% potassium iodide aqueous solution, and then dried at 50 ° C. for 4 minutes. To obtain a polarizer.
(Preparation of aqueous adhesive)
A solution was prepared by dissolving 100 g of PVA103 (manufactured by Kuraray), which is a polyvinyl alcohol resin, in 900 g of pure water. Next, by mixing 200 g of the produced PVA solution, 50 g of the aqueous urethane resin produced in Production Example 1, 8 g of Denacol EX-421 (manufactured by Nagase ChemteX), which is an aqueous epoxy compound, and 342 g of pure water until the solution is uniform. A water-based adhesive 1 was prepared. The viscosity of the aqueous adhesive 1 was 12 mPa · S.
(Creation of polarizing plate)
The transparent protective film 1 produced in Production Example 2 was subjected to alkali treatment with a 2.5 M sodium hydroxide aqueous solution at 40 ° C. for 60 seconds, and then washed with water for 3 minutes to carry out alkali treatment. Next, after applying the produced aqueous adhesive 1 to the acrylic resin layer side of the transparent protective film 1 subjected to alkali treatment, the produced polarizer is bonded to the produced polarizer using a roll laminator and dried at 70 ° C. for 10 minutes, A polarizing plate 1 was obtained. The evaluation results of the produced polarizing plate 1 are shown in the table.

Example 2
(Preparation of aqueous adhesive)
A solution was prepared by dissolving 100 g of GOHSEIMER LW-300 (manufactured by Nippon Synthetic Chemical Industry, saponification degree 53-60), which is a polyvinyl alcohol resin, in 900 g of pure water. Next, 200 g of the produced PVA solution, 50 g of the aqueous urethane resin produced in Production Example 1, 2 g of adipic acid dihydrazide (manufactured by Nippon Kasei), which is an aqueous amino compound, and 215 g of pure water are mixed until the solution is uniform, Adhesive 2 was prepared. The viscosity of the aqueous adhesive 2 was 10 mPa · S.
(Preparation of polarizing plate)
In Example 1 (Preparation of polarizing plate), except that the transparent protective film 1 was changed to the transparent protective film 2 produced in Production Example 3 and the aqueous adhesive 1 was changed to the aqueous adhesive 2 (Polarized light). The polarizing plate 2 was produced by the same method as the production of the plate (the side in contact with the polarizer was the polycarbonate layer side). The evaluation results of the produced polarizing plate 2 are shown in the table.

Example 3
(Preparation of aqueous adhesive)
A solution was prepared by dissolving 100 g of Goosefimer Z210 (produced by Nippon Synthetic Chemical Industry, acetoacetyl group-containing PVA), which is a polyvinyl alcohol resin, in 900 g of pure water. Next, 180 g of the produced PVA solution, 5 g of the aqueous urethane resin produced in Production Example 1, 2 g of WB40-100 (manufactured by Asahi Kasei Chemicals), which is an aqueous isocyanate compound, and 253 g of pure water are mixed until the solution becomes uniform. Adhesive 3 was produced. The viscosity of the aqueous adhesive 3 was 19 mPa · S.
(Preparation of polarizing plate)
Using the corona treatment device (manufactured by Kasuga Denki), the transparent protective film 3 produced in Production Example 4 is a wire electrode having an output power of 0.2 kW, a frequency of 33.1 kHz, a diameter of 1.2 mm, an electrode length of 240 mm, and between work electrodes. The discharge treatment was performed twice under the conditions of 3.0 mm and a conveyance speed of 1 m / min. Next, after applying the prepared aqueous adhesive 3 to the corona-treated surface side of the corona-treated transparent protective film 3, the resulting polarizer is bonded to the prepared polarizer using a roll laminator and dried at 100 ° C. for 5 minutes. A polarizing plate 3 was obtained. The evaluation results of the produced polarizing plate 3 are shown in the table.

Example 4
(Preparation of aqueous adhesive)
A uniform solution of 21 g of the PVA solution produced in Example 3, 100 g of the aqueous urethane resin produced in Production Example 1, 2.1 g of glyoxal (40% active ingredient, manufactured by Nippon Synthetic Chemical Industry), which is an aqueous aldehyde compound, and 952 g of pure water The aqueous adhesive 4 was produced by mixing until it became. The viscosity of the aqueous adhesive 4 was 4 mPa · S.
(Preparation of polarizing plate)
The transparent protective film 3 produced in Production Example 4 is used once with a remote atmospheric pressure plasma processing apparatus (manufactured by E-Square) under the conditions of an output of 1.2 kW, a nitrogen flow rate of 200 L / min, and a conveyance speed of 1 m / min. Surface treatment was performed. Next, after applying the produced aqueous adhesive 4 to the treated surface side of the plasma-treated transparent protective film 3, the produced polarizer is bonded to the produced polarizer using a roll laminator and dried at 100 ° C. for 5 minutes. A plate 4 was obtained. The evaluation results of the produced polarizing plate 4 are shown in the table.

Example 5
(Preparation of aqueous adhesive)
12.5 g of the PVA solution produced in Example 3, 9.4 g of the aqueous urethane resin produced in Production Example 1, 0.63 g of carbodilite V-02 (active ingredient 40%, manufactured by Nisshinbo), which is an aqueous carbodiimide compound, pure water The aqueous adhesive 5 was produced by mixing 152.5 g until the solution was uniform. The viscosity of the aqueous adhesive 5 was 3 mPa · S.
(Preparation of polarizing plate)
The transparent protective film 3 produced in Production Example 4 was subjected to a surface treatment using a via discharge excimer lamp (manufactured by USHIO INC.) Under nitrogen at 254 nm (4.9 eV) in an irradiation distance of 1 mm and an irradiation time of 360 seconds. Carried out. Next, after applying the produced aqueous adhesive 5 to the treated surface side of the transparent protective film 3 subjected to the surface treatment, the produced polarizer is bonded to the produced polarizer using a roll laminator and dried at 100 ° C. for 5 minutes. A plate 5 was obtained. The evaluation results of the produced polarizing plate 5 are shown in the table.

Claims (7)

A polarizing plate having an adhesive layer between the polarizer (A) and the protective film (B),
The film on the polarizer (A) side of the protective film (B) is made of an acrylic polymer, an alicyclic structure-containing polymer, or a polycarbonate,
A polarizing plate, wherein the adhesive layer is formed of an adhesive composition containing a polyvinyl alcohol resin, a urethane resin, and a crosslinking agent.   The polarizing plate according to claim 1, wherein the polyvinyl alcohol resin is a modified polyvinyl alcohol resin.   The polarizing plate according to claim 1, wherein the protective film (B) is a stretched film.   The polarizing plate according to any one of claims 1 to 3, wherein the crosslinking agent is selected from the group consisting of an aqueous epoxy compound, an aqueous amino compound, an aqueous isocyanate compound, an aqueous carbodiimide compound, and an aqueous aldehyde compound. Applying a water dispersion containing a polyvinyl alcohol resin, a urethane resin, and a crosslinking agent on the polarizer (A) and / or the protective film (B);
Bonding the polarizer (A) and the protective film (B);
The manufacturing method of the polarizing plate in any one of Claims 1-4 characterized by the above-mentioned. On the polarizer (A) and / or the protective film (B), the viscosity of the aqueous dispersion to be applied is
The production method according to claim 5, wherein the production method is 20 mPa · s or less. Before the step of applying the aqueous dispersion on the polarizer (A) and / or the protective film (B),
The method according to claim 5 or 6, comprising a step of surface-treating the protective film (B).