KR20140144175A - Laminate film, method for producing polarizing laminate film, and method for producing polarizing plate - Google Patents

Abstract

The present invention includes a base film made of a thermoplastic resin and a polyvinyl alcohol resin layer formed by coating on at least one surface of the base film, wherein the base film has a tensile modulus at 80 DEG C of 140 MPa or more And a method for producing a polarizing laminated film and a polarizing plate using the laminated film. The surface layer on the surface of the base film on which at least the polyvinyl alcohol-based resin layer is formed preferably comprises a crystalline thermoplastic resin having a degree of crystallinity of 58% or more.

Description

TECHNICAL FIELD [0001] The present invention relates to a laminated film, a laminated film, and a polarizing plate laminated film,

The present invention relates to a laminated film which can be suitably used as a polarizing laminated film having a polarizing layer or as a production intermediate of a polarizing plate. The present invention also relates to a process for producing a polarizing laminated film and a process for producing a polarizing plate.

The polarizing plate is widely used as a polarizing light supplying element in a liquid crystal display device and also as a polarizing light detecting element. Conventionally, as a polarizing plate, a protective film made of triacetyl cellulose or the like is bonded to a polarizing film made of a polyvinyl alcohol-based resin through an adhesive. In recent years, a liquid crystal display device such as a notebook type personal computer, Development to a device, development to a large-size television, and the like, thinner and thinner polarizers are required.

However, the polarizing film is produced by stretching and staining a film original of a polyvinyl alcohol-based resin (usually about 75 탆 in thickness), and the thickness of the stretched film is usually about 30 탆. Such thinning has been problematic because of the problem of productivity such that the film tends to be broken at the time of stretching.

Thus, a coating solution containing a polyvinyl alcohol-based resin is coated on a base film to form a polyvinyl alcohol-based resin layer to obtain a laminated film, which is then stretched as a base film and then stained to obtain a polyvinyl alcohol- There has been proposed a method of producing a laminate (polarizing laminated film) having a polarizer layer and a polarizing plate using the resin layer as a polarizer layer (for example, Japanese Patent Application Laid-Open No. 2000-338329 (Patent Document 1) Open Patent Publication No. 2009-098653 (Patent Document 2), Japanese Patent Application Laid-Open No. 2009-93074 (Patent Document 3), and Japanese Patent Application Laid-Open No. 2011-100161 (Patent Document 4)]. According to this method, a polyvinyl alcohol-based resin layer that is thinner than when a film original of a polyvinyl alcohol-based resin is used can be obtained.

Patent Document 1: Japanese Patent Application Laid-Open No. 2000-338329 Patent Document 2: JP-A-2009-098653 Patent Document 3: JP-A-2009-093074 Patent Document 4: Japanese Patent Laid-Open Publication No. 2011-100161

In the method including the step of forming a polyvinyl alcohol resin layer on a base film by coating a coating solution containing a polyvinyl alcohol resin to obtain a laminated film as described above, A step of removing the solvent in the coating layer by drying the base film on which the coating layer is formed is required. However, during drying, defects such as wrinkles and folding may occur in the substrate film, and coating defects may be formed on the defective portions, resulting in drying failure.

Therefore, an object of the present invention is to provide a laminated film comprising a polyvinyl alcohol resin layer formed by coating a base film of a coating liquid containing a polyvinyl alcohol-based resin and subsequent drying, Which is capable of sufficiently suppressing defects such as wrinkles or folding and drying defects of the coating layer caused thereby.

Another object of the present invention is to provide a method for producing a laminated film by forming a polyvinyl alcohol resin layer by coating a base film of a coating liquid containing a polyvinyl alcohol resin and subsequent drying to obtain a laminated film, In a method of producing a polarizing laminated film or a polarizing plate by using the polyvinyl alcohol resin layer as a polarizer layer, defects such as wrinkles or folding of the base film during drying and drying failure of the coating layer caused thereby And to provide a method capable of efficiently producing a polarizing laminated film or a polarizing plate.

The present invention is as follows.

[1] A polyester film comprising a base film made of a thermoplastic resin and a polyvinyl alcohol resin layer formed on at least one side of the base film by coating, wherein the base film has a tensile elastic modulus at 80 ° C of 140 MPa or more, Laminated film.

[2] The base film is characterized in that at least the surface layer of the surface on which the polyvinyl alcohol-based resin layer is formed is made of a crystalline thermoplastic resin, and the surface layer composed of the crystalline thermoplastic resin has a crystallinity of at least 58% ].

[3] The laminated film according to [2], wherein the surface layer composed of the crystalline thermoplastic resin of the base film contains a nucleating agent.

[4] The laminated film according to any one of [1] to [3], wherein the polyvinyl alcohol-based resin layer has a thickness of 3 to 30 μm.

[5] A process for producing a polarizing laminated film, which comprises the steps of uniaxially stretching as a laminated film and then dying a polyvinyl alcohol resin layer with a dichroic dye to form a polarizer layer. [1] to [4 A laminated film according to any one of claims 1 to 3.

[6] A method for producing a stretched film, which comprises a stretching step of uniaxially stretching the laminated film according to any one of [1] to [4]

And a dyeing step of obtaining a polarizing laminated film by dying a polyvinyl alcohol-based resin layer of the resulting stretched film with a dichroic dye to form a polarizer layer.

[7] A process for producing a base film, comprising the steps of: preparing a base film comprising a thermoplastic resin film having a tensile elastic modulus at 80 ° C of 140 MPa or more;

A resin layer forming step of forming a polyvinyl alcohol resin layer by coating a coating solution containing a polyvinyl alcohol resin on at least one surface of the base film and then drying the resin film to obtain a laminated film,

A stretching step of uniaxially stretching the obtained laminated film to obtain a stretched film,

And a dyeing step of obtaining a polarizing laminated film by dying a polyvinyl alcohol-based resin layer of the resulting stretched film with a dichroic dye to form a polarizer layer.

[8] A process for producing a base film, comprising the steps of preparing a base film by heating a thermoplastic resin film to obtain a base film,

A resin layer forming step of forming a polyvinyl alcohol resin layer by coating a coating solution containing a polyvinyl alcohol resin on at least one surface of the obtained base film and then drying the resin film to obtain a laminated film,

A stretching step of uniaxially stretching the obtained laminated film to obtain a stretched film,

And a dyeing step of obtaining a polarizing laminated film by dying a polyvinyl alcohol resin layer of the resulting stretched film with a dichroic dye to form a polarizer layer,

Wherein the base film preparation step comprises a step of heat-treating the thermoplastic resin film at a temperature equal to or higher than the drying temperature in the resin layer formation step.

[9] A primer layer for forming a primer layer is formed between the base film preparation step and the resin layer formation step by coating a coating solution for forming a primer layer on the surface of the base film on which the coating solution is coated, Forming process,

The method for preparing a polarizing laminated film according to [8], wherein the base film preparation step comprises a step of heat-treating the thermoplastic resin film at a temperature equal to or higher than the drying temperature in the primer layer formation step.

A base film preparation step of preparing a base film made of a thermoplastic resin film wherein at least the surface layer of the surface on which the polyvinyl alcohol resin layer is formed in the next step is composed of a crystalline thermoplastic resin containing a nucleating agent;

A resin layer forming step of forming a polyvinyl alcohol resin layer by coating a coating solution containing a polyvinyl alcohol resin on at least one surface of the base film and then drying the resin film to obtain a laminated film,

A stretching step of uniaxially stretching the obtained laminated film to obtain a stretched film,

And a dyeing step of obtaining a polarizing laminated film by dying a polyvinyl alcohol-based resin layer of the resulting stretched film with a dichroic dye to form a polarizer layer.

[11] The method for producing a polarizing laminated film according to any one of [6] to [10], wherein the laminated film is uniaxially stretched at a draw ratio of more than 5 times.

[12] The method for producing a polarizing laminated film according to any one of [6] to [11], wherein the polyvinyl alcohol-based resin layer in the laminated film has a thickness of 3 to 30 μm.

[13] A process for producing a polarizing laminated film, comprising the steps of: preparing a polarizing laminated film obtained by the production method according to any one of [6] to [12]

A step of bonding a protective film to the polarizer layer in the polarizing laminated film to obtain a bonded film,

And peeling the base film from the resulting laminated film.

According to the present invention, by using a substrate film having excellent heat resistance with a tensile modulus of 140 MPa or more at 80 캜, defects such as wrinkles or folding which may occur in the base film and drying problems of the coating layer resulting therefrom It is possible to provide an inhibited laminated film. The laminated film related to the present invention can be suitably used as a production intermediate of a polarizing laminated film or a polarizing plate.

Further, according to the present invention, it is possible to produce a laminated film without the above-described problems by using a base film having excellent heat resistance with a tensile modulus of 140 MPa or more at 80 DEG C, , A polarizing laminated film or a polarizing plate can be efficiently produced without deteriorating the stretchability and dyeability.

1 is a schematic cross-sectional view showing an example of the layer structure of a laminated film related to the present invention.
2 is a schematic cross-sectional view showing an example of the layer structure of a stretched film according to the present invention.
3 is a schematic cross-sectional view showing an example of the layer structure of the polarizing laminated film related to the present invention.
Fig. 4 is a flowchart showing a preferred embodiment of a laminated film, a polarizing laminated film and a polarizing plate production method according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail to explain a laminated film, a method for producing the same, a method for producing a polarizing laminated film, and a method for producing a polarizing plate.

<Laminated film>

1 is a schematic cross-sectional view showing an example of the layer structure of a laminated film related to the present invention. The laminated film 100 shown in Fig. 1 is composed of a base film 101 made of a thermoplastic resin and a polyvinyl alcohol-based resin layer 102 laminated on the base film 101. Fig. The laminated film of the present invention may have a polyvinyl alcohol resin layer 102 only on one side of the base film 101 as shown in the example shown in Fig. A resin layer 102 may be provided. The laminated film of the present invention may have a primer layer or the like (not shown) interposed between the base film 101 and the polyvinyl alcohol resin layer 102.

The base film 101 exhibits high heat resistance, specifically, a tensile modulus at 80 캜 of 140 MPa or more.

The polyvinyl alcohol-based resin layer 102 is a layer formed by applying a coating liquid containing a polyvinyl alcohol-based resin to the base film 101 and then drying it. By forming the polyvinyl alcohol-based resin layer 102 by coating, the thickness of the polyvinyl alcohol-based resin layer 102 is reduced to 30 μm or less, preferably 20 μm or less, more preferably 10 μm or less .

Since the tensile modulus at 80 DEG C of the laminated film of the present invention is as large as 140 MPa or more, defects such as wrinkles or folding at the time of drying the coating layer and the drying failure of the coating layer due to the wrinkle or folding are effectively suppressed.

As a method for suppressing the above-described problems, a thermoplastic resin having a very high melting point (or glass transition temperature) is used for the base film 101, or a film made of an amorphous thermoplastic resin, 101). However, in the case of the former, the stretching of the laminated film 100 can be very difficult. In the latter case, since the orientation of the polymer chains of the thermoplastic resin constituting the base film 101 is strong, May be adversely affected.

The laminated film of the present invention can be suitably used as a polarizing laminated film having a polarizer layer or an intermediate for producing a polarizing plate, as will be described later in detail. For example, when the laminated film 100 shown in Fig. 1 is used as a manufacturing intermediate, the laminated film 100 is uniaxially stretched by the base film 101 to form a stretched film 200 (stretched base film (Which is composed of the polyvinyl alcohol-based resin layer 201 and the polyvinyl alcohol-based resin layer 202 drawn), and the obtained polyvinyl alcohol-based resin layer 202 of the drawn film 200 are dyed with a dichroic dye, The polarizing layer 302 is laminated on the base film 301 as shown in Fig. 3 through a dyeing step S40 to form a polarizing laminated film 300. Fig.

The polarizing plate is manufactured by a bonding step S50 of bonding a protective film to the polarizing layer 302 of the polarizing laminated film 300 to obtain a bonding film and a peeling step S60 of peeling the base film 301 from the obtained bonding film can do.

By using the laminated film in which the above problems are suppressed, the polarizing laminated film and the polarizing plate can be produced without deteriorating the stretchability and dyeability.

[1] Base film

The base film 101 is a film made of a thermoplastic resin having a tensile elastic modulus at 80 DEG C of 140 MPa or more. The tensile modulus at 80 캜 is preferably 150 MPa or more, and more preferably 155 MPa or more, from the viewpoint of more effectively suppressing the above problems in drying the coating layer.

The tensile modulus of elasticity of the base film 101 can be determined by cutting a test piece of a predetermined size from the base film 101 and performing a tensile test. Further, in order to determine the tensile modulus at 80 캜, a tensile tester equipped with a thermostat is used. In the following examples, a tensile test was carried out using an autoclave AG-I universal testing machine manufactured by Shimadzu Corporation equipped with a thermostatic chamber.

The reason why the tensile modulus at &quot; 80 DEG C &quot; is adopted in the present invention is as follows. In the present invention, a coating solution containing a polyvinyl alcohol resin is coated on a base film 101 and then dried to form a polyvinyl alcohol resin layer 102 to produce a laminated film 100. Before forming the polyvinyl alcohol-based resin layer 102, a coating solution for forming a primer layer is coated on the surface of the base film 101 on which the polyvinyl alcohol-based resin layer 102 is formed And then dried to form a primer layer. Since the drying treatment is carried out at about 80 캜, the present invention adopts the tensile elastic modulus at 80 캜.

As an effective method for obtaining the base film 101 by raising the tensile elastic modulus of the thermoplastic resin film having a tensile elastic modulus at 80 DEG C of less than 140 MPa to not less than 140 MPa,

1) a method of heat-treating a thermoplastic resin film at a temperature not lower than the drying temperature in the subsequent resin layer forming step S20, and

2) a method of increasing the degree of crystallization of the surface layer (corresponding to the surface layer 101a in Fig. 1) of the surface on which the polyvinyl alcohol-based resin layer is formed in the thermoplastic resin film.

The method 1) can be adopted regardless of whether the thermoplastic resin constituting the thermoplastic resin film is crystalline or amorphous.

2) can be employed when at least the surface layer of the thermoplastic resin film is composed of a crystalline thermoplastic resin. The inventors of the present invention have found that when the degree of crystallinity of the surface layer 101a is 58% or more, the tensile modulus of the base film 101 at 80 캜 is about 140 MPa or more. As a method of raising the crystallinity of the surface layer 101a to not less than 58%, there is a method of heating the thermoplastic resin film like the method 1), and a method of adding a nucleating agent to the surface layer composed of at least a crystalline thermoplastic resin is effective Do. The crystallinity of the surface layer 101a of the base film 101 is preferably 59% or more, and more preferably 60% or more.

The degree of crystallization of the surface layer 101a will be generally described by a value obtained by X-ray diffraction (XRD). From the crystalline scattering integral intensity (Ic) of the crystalline portion determined by the X-ray diffraction method and the amorphous scattering integral intensity (Ia) of the amorphous portion, the degree of crystallization is represented by the following formula:

Crystallinity = (Ic) / [(Ic) + (Ia)]

.

Depending on the kind of the thermoplastic resin constituting the surface layer 101a of the base film 101, it may be replaced by an attenuated total reflection method (ATR method) or a method of measuring specific gravity.

Particularly, when the surface layer 101a of the base film 101 is made of a polypropylene type resin, the degree of crystallinity can be obtained by the following method. That is, the infrared spectroscopy of the surface of the film made of the polypropylene resin is first measured by the attenuation total reflection method (ATR method) using an infrared spectrophotometer. The ATR method employed here is a method of directly measuring the germanium crystal prism by closely contacting the measurement surface of the base film 101 and measuring the infrared spectra relating to the layer of about several micrometers constituting the pole surface of the base film 101 Can be obtained. The degree of crystallinity X of the surface of the film made of a polypropylene type resin is determined based on the obtained infrared spectral spectrum by the following formula:

Crystallinity X (%) = 109 x (A ₉₉₈ -A ₉₂₀ ) / (A ₉₇₄ -A ₉₂₀ ) -31.4

( _Wherein A ₉₉₈ , A ₉₇₄ and A ₉₂₀ mean absorbance at wavenumbers 998 cm ^-1 , 974 cm ^-1 and 920 cm ^-1 , respectively).

. &Lt; / RTI &gt;

The method and formula for determining the degree of crystallization of the surface of the film made of the polypropylene resin shown here are described in, for example,

J. Appl. Polym. Sci., 2, 166 (1959),

Koichi Nishida and Iwamoto Reiichi, Materials Analysis by Infrared Method - Fundamentals and Applications-, Kodansha Scientific, August 1986, pages 214 to 215, and this method is generally known .

The thermoplastic resin constituting the base film 101 is preferably excellent in transparency, mechanical strength, thermal stability, stretchability and the like. Specific examples of such a thermoplastic resin include polyolefin-based resins such as a chain-like polyolefin-based resin and a cyclic polyolefin-based resin (norbornene-based resin and the like); Polyester-based resin; (Meth) acrylic resins; Cellulose ester-based resins such as cellulose triacetate and cellulose diacetate; Polycarbonate resin; Polyvinyl alcohol-based resin; Polyvinyl acetate resin; Polyarylate resins; Polystyrene type resin; Polyether sulfone type resin; Polysulfone resins; Polyamide based resin; Polyimide resin; And mixtures and copolymers thereof, and the like.

The base film 101 may be a single-layer structure composed of one resin layer made of one kind or two or more kinds of thermoplastic resins, or a multi-layer structure in which a plurality of resin layers made of one kind or two or more kinds of thermoplastic resins are laminated.

Examples of the chain-like polyolefin-based resin include a homopolymer of a chain-like olefin such as a polyethylene resin and a polypropylene resin, and a copolymer composed of two or more kinds of chain olefins. The base film 101 made of a chain-like polyolefin-based resin is preferable because it is easy to stably stretch at a high magnification. Among them, the base film 101 is preferably made of a polypropylene resin (a polypropylene resin which is a homopolymer of propylene or a copolymer mainly composed of propylene), a polyethylene resin (a polyethylene resin which is a homopolymer of ethylene, And the like), and the like.

One of the examples suitably used as the thermoplastic resin constituting the base film 101 is a copolymer composed mainly of propylene and another monomer copolymerizable therewith.

Other monomers copolymerizable with propylene include, for example, ethylene and? -Olefin. As the? -olefin, an? -olefin having 4 or more carbon atoms is preferably used, and more preferably an? -olefin having 4 to 10 carbon atoms. Specific examples of the? -Olefin having 4 to 10 carbon atoms include straight chain monoolefins such as 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene and 1-decene; Branched monoolefins such as 3-methyl-1-butene, 3-methyl-1-pentene and 4-methyl-1-pentene; Vinyl cyclohexane and the like. The copolymer of propylene and other monomer copolymerizable therewith may be a random copolymer or a block copolymer.

The content of the other monomer in the copolymer is, for example, from 0.1 to 20% by weight, and preferably from 0.5 to 10% by weight. The content of the other monomers in the copolymer can be determined by performing infrared (IR) spectrum measurement according to the method described on page 616 of "Polymer Analysis Handbook" (published by Kinokuniya Bookstore, 1995).

Of these, propylene homopolymer, propylene-ethylene random copolymer, propylene-1-butene random copolymer or propylene-ethylene-1-butene random copolymer are preferably used as the polypropylene type resin.

The stereoregularity of the polypropylene resin is preferably substantially isotactic or syndiotactic. The base film 101 made of a polypropylene resin having substantially stereospecificity of isotacticity or syndiotacticity is relatively easy to handle and has excellent mechanical strength under a high temperature environment.

The base film 101 may be composed of one kind of a chain-like polyolefin-based resin, or may be composed of a mixture of two or more kinds of a chain-like polyolefin-based resin, or may be composed of a copolymer of two or more kinds of a chain- .

The cyclic polyolefin-based resin is a generic name of resins polymerized by using cyclic olefins as polymerized units. For example, JP-A-1-240517, JP-A-3-14882, JP- 122137, and the like. Specific examples of the cyclic polyolefin-based resin include ring-opened (co) polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers of cyclic olefins and chain olefins such as ethylene and propylene (typically, random copolymers ), Graft polymers obtained by modifying these with an unsaturated carboxylic acid or a derivative thereof, and hydrides thereof. Of these, norbornene-based resins using norbornene monomers such as norbornene and polycyclic norbornene-based monomers as the cyclic olefins are preferably used.

Various products are commercially available as the cyclic polyolefin-based resin. (Commercially available from TOPAS ADVANCED POLYMERS GmbH, available from Polyplastics Co.), &quot; ATON &quot; (manufactured by JSR Corporation), and &quot; ZEONOR "(manufactured by Nippon Zeon Co., Ltd.)," Zeonex "(manufactured by Nippon Zeon Co., Ltd.) and" Apel "(manufactured by Mitsui Chemicals, Inc.).

(Manufactured by Sekisui Chemical Co., Ltd.), &quot; SCA40 &quot; (manufactured by Sekisui Chemical Co., Ltd.), &quot; Zeonoa Film &quot; A commercially available product of the formed annular polyolefin-based resin film may be used as the base film 101 or a thermoplastic resin film having a tensile elastic modulus at 80 DEG C of less than 140 MPa for forming the same.

The base film 101 may be composed of one kind of cyclic polyolefin resin or may be composed of a mixture of two or more kinds of cyclic polyolefin resins and may be composed of a copolymer of two or more kinds of cyclic polyolefin resins .

The polyester-based resin is a resin having an ester bond, and is generally composed of a polycondensation product of a polycarboxylic acid or a derivative thereof and a polyhydric alcohol. As the polycarboxylic acid or its derivative, a divalent dicarboxylic acid or a derivative thereof can be used, and examples thereof include terephthalic acid, isophthalic acid, dimethylterephthalate, dimethyl naphthalenedicarboxylate and the like. As the polyhydric alcohol, a dihydric diol can be used, and examples thereof include ethylene glycol, propanediol, butanediol, neopentyl glycol, and cyclohexanedimethanol.

Specific examples of the polyester-based resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethyl terephthalate, Hexane dimethyl naphthalate and the like.

The base film 101 may be composed of one kind of polyester resin or a mixture of two or more kinds of polyester resins or may be composed of a copolymer of two or more kinds of polyester resins .

As the (meth) acrylic resin, any suitable (meth) acrylic resin may be employed. Specific examples of the (meth) acrylic resin include poly (meth) acrylic acid esters such as polymethyl methacrylate, methyl methacrylate- (meth) acrylic acid copolymer, methacrylic acid methyl- (meth) (Meth) acrylic acid methyl-styrene copolymer (MS resin), a polymer having an alicyclic hydrocarbon group (for example, methyl methacrylate-methyl methacrylate-cyclohexyl methacrylate Copolymers, methyl methacrylate- (meth) acrylate norbornyl copolymers, etc.). Preferably, poly (meth) acrylate C _1-6 alkyl such as poly (meth) acrylate is used, and more preferably, methyl methacrylate is used as a main component (50 to 100 wt%, preferably 70 to 100 wt% By weight) is used.

The base film 101 may be composed of one kind of (meth) acrylic resin or may be composed of a mixture of two or more kinds of (meth) acrylic resins, and composed of a copolymer of two or more kinds of (meth) acrylic resins .

The cellulose ester resin is an ester of cellulose and a fatty acid. Specific examples of the cellulose ester resin include cellulose triacetate, cellulose diacetate, cellulose tripropionate, cellulose dipropionate and the like. Of these, cellulose triacetate (triacetylcellulose) is particularly preferable. Cellulose triacetate is commercially available in many products, and is advantageous in terms of availability and cost. Examples of commercially available products of cellulose triacetate include trade names such as "Fujitac TD80" (manufactured by Fuji Film), "Fujitac TD80UF" (manufactured by Fujifilm Corporation), "Fujitac TD80UZ" (Trade name) manufactured by Fuji Photo Film Co., Ltd.), Fujitac TD40UZ (manufactured by Fuji Film Co., Ltd.), KC8UX2M (manufactured by Konica Minolta Opto Corporation), and KC4UY (manufactured by Konica Minolta Opto Corporation).

The base film (101) may be composed of one kind of cellulose ester type resin, or may be composed of a mixture of two or more kinds of cellulose ester type resins or a copolymer of two or more kinds of cellulose ester type resins .

The polycarbonate resin is an engineering plastic composed of a polymer having a monomer unit bonded through a carbonate group, and is a resin having high impact resistance, heat resistance, flame retardancy, and transparency. The polycarbonate resin constituting the base film 101 may be a resin called a modified polycarbonate such as a polymer skeleton modified to lower the photoelastic coefficient or a copolymerized polycarbonate improved in wavelength dependency.

Various products of polycarbonate resin are commercially available. Examples of commercially available products of the polycarbonate resin include trade names such as "Panlite" (manufactured by Dainippon Ink & Chemicals, Inc.), "Yuferon" (manufactured by Mitsubishi Engineering Plastics Co., Ltd.), "SD Polycar" (Manufactured by Dow Chemical Co., Ltd.) and Cariba (manufactured by Dow Chemical Co., Ltd.).

The base film 101 may be composed of one kind of polycarbonate resin, or may be composed of a mixture of two or more kinds of polycarbonate resins or a copolymer of two or more kinds of polycarbonate resins .

Among them, a polypropylene resin is preferably used from the viewpoint of stretchability and heat resistance.

In addition to the above-mentioned thermoplastic resin, any suitable additives may be added to the base film 101. Examples of such additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, coloring inhibitors, flame retardants, nucleating agents, antistatic agents, pigments, and colorants. The content of the thermoplastic resin in the base film 101 is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, particularly preferably 70 to 97% to be. When the content of the thermoplastic resin in the base film (101) is less than 50% by weight, high transparency inherently possessed by the thermoplastic resin may not be sufficiently manifested.

The melting point of the thermoplastic resin constituting the base film 101 is preferably 110 占 폚 or higher, and more preferably 130 占 폚 or higher. If the melting point of the thermoplastic resin is less than 110 캜, the base film 101 tends to melt in the stretching step S30 described later, so that the stretching temperature can not be raised sufficiently and stretching more than 5 times is difficult. The melting point of the thermoplastic resin is a value measured at a heating rate of 10 ° C / min based on ISO 3146.

The thickness of the base film 101 can be appropriately determined, but it is preferably 1 to 500 占 퐉, more preferably 1 to 300 占 퐉, still more preferably 5 to 200 占 퐉 in view of workability such as strength and handling properties And most preferably from 5 to 150 mu m.

[2] Polyvinyl alcohol-based resin layer

The polyvinyl alcohol resin layer 102 is a layer formed by applying a coating liquid containing a polyvinyl alcohol resin to the base film 101 and then drying it. Through the drawing step S30 and the dyeing step S40, (302). According to such a coating forming method, the thickness of the polyvinyl alcohol-based resin layer and further the polarizer layer can be reduced, which is advantageous for thinning of the polarizing laminated film and the polarizing plate. Further, since the substrate film 101 having excellent heat resistance with a tensile modulus at 80 DEG C of 140 MPa or more is used, defects such as wrinkles or folds at the time of drying the coating layer and drying problems of the coating layer It can be suppressed effectively.

As described above, the polyvinyl alcohol-based resin layer 102 may be formed on only one side of the base film 101 or on both sides thereof. It is advantageous in terms of production efficiency of the polarizing plate because two polarizing plates can be obtained from a single polarizing laminated film while curling the film which may occur during production of the polarizing laminated film or polarizing plate.

The thickness of the polyvinyl alcohol-based resin layer 102 in the laminated film 100 is preferably 3 to 30 占 퐉, more preferably 5 to 20 占 퐉. The polyvinyl alcohol-based resin layer 102 having a thickness within this range is subjected to a stretching step S30 and a dyeing step S40 to be described later so as to form a polarizer layer 102 having good dyability and excellent polarizing properties of a dichroic dye, (302) can be obtained. When the thickness of the polyvinyl alcohol-based resin layer 102 exceeds 30 占 퐉, the thickness of the polarizer layer 302 may exceed 10 占 퐉. If the thickness of the polyvinyl alcohol-based resin layer 102 is less than 3 占 퐉, the layer becomes too thin after stretching and the dyeability tends to deteriorate.

&Lt; Laminated film and method for producing a polarizing laminated film >

Fig. 4 is a flowchart showing a preferred embodiment of a laminated film, a polarizing laminated film and a polarizing plate production method according to the present invention. The method for producing a laminated film according to the present embodiment includes the following steps:

A base film preparation step S10 for preparing a base film made of a thermoplastic resin film having a tensile elastic modulus at 80 DEG C of 140 MPa or more,

A resin layer forming step S20 for obtaining a laminated film by forming a polyvinyl alcohol resin layer by coating a coating solution containing a polyvinyl alcohol resin on at least one surface of a base film and then drying

In this order.

Further, the method for producing a polarizing laminated film of the present embodiment includes the following steps:

A base film preparation step S10 for preparing a base film made of a thermoplastic resin film having a tensile elastic modulus at 80 DEG C of 140 MPa or more,

A resin layer forming step S20 for forming a polyvinyl alcohol resin layer by coating a coating solution containing a polyvinyl alcohol resin on at least one surface of a base film and then drying to obtain a laminated film,

A stretching step S30 for uniaxially stretching the obtained laminated film to obtain a stretched film,

A dyeing step S40 for obtaining a polarizing laminated film by dying a polyvinyl alcohol-based resin layer of the obtained stretched film with a dichroic dye to form a polarizer layer

In this order.

As described later, in the polarizing plate of the present embodiment, the protective film is bonded on the polarizing layer of the polarizing laminated film obtained by performing the dyeing step S40 up to the step S40 to obtain a bonded film (bonding step S50) (Peeling step S60).

Hereinafter, each step of S10 to S40 will be described in more detail.

[1] Base film preparation step S10

This step is a step of preparing a base film 101 made of a thermoplastic resin film having a tensile elastic modulus at 80 占 폚 of 140 MPa or more (preferably 150 MPa or more, and more preferably 155 MPa or more). As mentioned above, as an effective method for obtaining such a base film 101,

1) a method of heat-treating a thermoplastic resin film at a temperature not lower than the drying temperature in the subsequent resin layer forming step S20, and

2) A method of raising the crystallinity of the surface layer 101a on the surface of the thermoplastic resin film on which the polyvinyl alcohol resin layer is formed to 58% or more (preferably 59% or more, and more preferably 60% or more) .

As mentioned above, the method 1) can be employed irrespective of whether the thermoplastic resin constituting the thermoplastic resin film is crystalline or amorphous. 2) can be employed when at least the surface layer of the thermoplastic resin film is composed of a crystalline thermoplastic resin. 2), a method of raising the crystallinity of the surface layer 101a to not less than 58% includes a method of heat-treating the thermoplastic resin film as in the method 1) And a method of adding a nucleating agent.

As described above, the base film preparation step S10 is a step of heating the thermoplastic resin film at a temperature not lower than the drying temperature in the subsequent resin layer formation step S20 to obtain the base film 101 (hereinafter referred to as &quot; heat treatment step S10- Or at least the surface layer 101a (the surface layer of the surface on which the polyvinyl alcohol-based resin layer 102 is formed in the subsequent resin layer forming step S20) is made of a crystalline thermoplastic resin containing a nucleating agent (Hereinafter referred to as &quot; nucleating agent addition step S10-b &quot;) for preparing a base film 101 made of a thermoplastic resin film. The base film preparation step S10 may include both the heat treatment step S10-a and the nucleating agent addition step S10-b.

In the heat treatment step S10-a, the thermoplastic resin film is heat-treated at a temperature equal to or higher than the drying temperature in the subsequent resin layer formation step S20 so that the obtained base film 101 has a tensile elastic modulus at 80 DEG C of 140 MPa or more. As the thermoplastic resin constituting the thermoplastic resin film, the crystalline or amorphous thermoplastic resin exemplified above can be used. At least the surface layer of the thermoplastic resin film is made of a crystalline thermoplastic resin when the degree of crystallization of the surface layer 101a is increased to 58% or more and the tensile elastic modulus thereof is 140 MPa or more.

Specific examples of the crystalline thermoplastic resin include, for example, a chain type polyolefin resin, a polyester resin, a crystalline cellulose ester resin, a polyvinyl alcohol resin, a polystyrene resin, a polyamide resin, a polyimide resin, , Copolymers, and the like. More specific examples of the crystalline, chain-like polyolefin-based resin include homopolymers composed of ethylene, propylene or an? -Olefin having 4 to 20 carbon atoms, and copolymers comprising two or more kinds of these monomers. More specific examples of the crystalline polyester-based resin include polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate.

(Annealing) the thermoplastic resin film at a temperature equal to or higher than the drying temperature in the resin layer forming step S20, the thermoplastic resin film is crystallized and the heat resistance of the obtained base film 101 is improved. As a result, in the resin layer forming step S20 of the next step, when the substrate film 101 is heated for drying and removing the solvent in the layer (coating layer) made of the coating liquid, defects such as wrinkles and folding occur, It is possible to effectively suppress the occurrence of drying failure due to the coating liquid being solidified in the defective portion. The drying temperature in the resin layer forming step S20 as referred to herein means the maximum temperature at the time of drying.

In the case where the heat treatment step S10-a itself is not included or when the heat treatment step S10-a does not include the step of heat-treating the thermoplastic resin film at a temperature not lower than the drying temperature in the resin layer formation step S20, (101) does not have sufficient heat resistance, the above problems may occur, and productivity and yield may be lowered.

The heat treatment temperature in the heat treatment step S10-a varies depending on the material of the thermoplastic resin film and the drying temperature in the resin layer formation step S20, but in the case where the solvent of the coating solution contains water, The drying temperature is desirably 80 DEG C or higher, and the heat treatment temperature is preferably 80 DEG C or higher, more preferably 90 DEG C or higher. Depending on the material of the thermoplastic resin film, the crystallization of the base film 101 can be favorably advanced by setting the heat treatment temperature to 80 deg. C or higher, preferably 90 deg. C or higher. The heat treatment temperature is usually adjusted to be lower than the phase transition temperature (melting point or glass transition temperature) of the thermoplastic resin film.

The heat treatment time in the heat treatment step S10-a is preferably 3 seconds to 5 minutes, preferably 5 seconds to 3 minutes. By setting the heat treatment time to 3 seconds or more, an effect of improving the heat resistance of the base material film 101 is obtained. If the heat treatment time exceeds 5 minutes, the productivity is deteriorated.

The heat treatment process S10-a may be a single-stage heat treatment process or a combination of multi-stage heat treatment processes. In the former case, the heat treatment step is a step of heat-treating the thermoplastic resin film at a temperature equal to or higher than the drying temperature in the resin layer forming step S20. In the latter case, one or two or more steps of the multi-step heat treatment step is a step of heat-treating the thermoplastic resin film at a temperature equal to or higher than the drying temperature in the resin layer forming step S20. The heating process at each stage constituting the heat treatment process S10-a includes, for example, a zone heating method in which the material is heated and dried in a drying oven (oven), a method of heating and drying in contact with hot roll, A method of heating and drying while stretching in a direction perpendicular to the surface of the substrate, and the like. For example, a plurality of types of heat treatment methods may be combined in the same manner as the first stage heating by the heating roll and the second heating by zone heating.

In the case where the heat treatment step S10-a is a combination of multi-step heat treatment steps, the heat treatment step S10-a includes a step of heat-treating the thermoplastic resin film at a temperature lower than the drying temperature in the resin layer formation step S20 can do.

In the case where the heat treatment step S10-a is a combination of multi-step heat treatment steps, the heat treatment time in the whole heat treatment step S10-a is preferably 3 seconds to 5 minutes, Sec to 3 minutes.

In the case where at least the surface layer of the thermoplastic resin film is composed of the crystalline thermoplastic resin, the maximum heat treatment temperature and the heat treatment time in the heat treatment step S10-a are set so that the degree of crystallization of the base film 101 does not excessively increase, The material of the thermoplastic resin film, and the like. If the maximum heat treatment temperature is excessively increased or the heat treatment time is excessively long, the degree of crystallization of the base film 101 becomes excessively high, and the stretchability tends to be impaired.

In the present step, in the case where at least the surface layer of the thermoplastic resin film is composed of the crystalline thermoplastic resin, in order to more effectively increase the degree of crystallization of at least the surface layer 101a in the base film 101, May be performed. In the case where the thermoplastic resin film is made of a resin that is easy to be oriented and crystallized, for example, a polyester-based resin such as polyethylene terephthalate, the stretching treatment is particularly effective for improving the degree of crystallization.

The stretching method may be any of longitudinal stretching, transverse stretching, and oblique stretching, or a plurality of stretching methods may be combined. Among them, it is preferable to include transverse stretching in that a base film 101 having a larger area can be obtained. The draw ratio (the total draw ratio when these are combined in a plurality of draw methods) is preferably 1.01 to 5 times, and more preferably 1.01 to 3 times. If the stretching magnification is 5 times or less, the degree of crystallization does not become excessively high, and the stretching property of the laminated film 100 in the stretching step S30 can be sufficiently secured. If the stretching magnification is too high, the base film 101 becomes loose and the stretchability deteriorates.

Between the substrate film preparation step S10 and the resin layer formation step S20 described later, a base film 101 is coated with a primer film 101, A step of forming a primer layer for forming a layer can be set. The primer layer can be formed by coating a coating solution for forming a primer layer on the base film 101 and then drying it. Therefore, when this primer layer forming step is carried out, defects such as wrinkles and folding occur in the base film 101 at the time of drying the coating layer in the above step, or the coating solution is filled in the defective part It is preferable that the heat treatment step S10-a includes a step of heat-treating the thermoplastic resin film at a temperature equal to or higher than the drying temperature in the primer layer forming step in order to effectively suppress the occurrence of drying failure.

The step of heat-treating the thermoplastic resin film at a temperature equal to or higher than the drying temperature in the primer layer forming step may be the same step as the step of heat-treating the thermoplastic resin film at the temperature above the drying temperature in the resin layer forming step S20 described above, Or may be a heat treatment step of different steps included in the heat treatment step S10-a.

With regard to the heat treatment temperature and the heat treatment time in the step of heat-treating the thermoplastic resin film at the temperature not lower than the drying temperature in the primer layer forming step, the thermoplastic resin film is heat-treated at a temperature not lower than the drying temperature in the resin layer- Quot; process &quot; is cited.

On the other hand, when the substrate film preparation step S10 is performed with the nucleating agent addition step S10-b, the surface layer 101a of the surface on which the polyvinyl alcohol resin layer 102 is formed at least in the resin layer formation step S20, And a thermoplastic resin film composed of a crystalline thermoplastic resin containing a thermoplastic resin is prepared. By containing the nucleating agent, the crystallinity of at least the surface layer 101a can be made 58% or more.

The kind of the thermoplastic resin constituting the thermoplastic resin film is not particularly limited as long as at least the surface layer 101a is composed of a crystalline thermoplastic resin and the entire thermoplastic resin film may be composed of a crystalline thermoplastic resin, In the case of a multilayer structure, only the layer including the surface layer 101a may be formed of a crystalline thermoplastic resin and the other layer may be composed of an amorphous thermoplastic resin. Specific examples of the crystalline thermoplastic resin are as described above.

The base film 101, which is a thermoplastic resin film containing the nucleating agent in the surface layer 101a, is prepared by adding a nucleating agent to the thermoplastic resin raw material constituting the base film 101, kneading the same, and forming the raw material of the thermoplastic resin containing the nucleating agent by a known method Can be obtained.

The nucleating agent is a substance that becomes the nucleus of crystals. Since nuclei are formed much by the addition of the nucleating agent, the degree of crystallization of the crystalline thermoplastic resin portion including the nucleating agent increases during film formation of the thermoplastic resin raw material, and the heat resistance is improved. As a result, in the resin layer forming step S20 of the next step, when the substrate film 101 is heated for drying and removing the solvent in the layer (coating layer) made of the coating liquid, defects such as wrinkles and folding occur, It is possible to effectively suppress the occurrence of drying failure due to the coating liquid being solidified in the defective portion.

As the nucleating agent, any of an organic nucleating agent and an inorganic nucleating agent may be used.

Specific examples of the organic nucleating agent include, for example, carboxylic acids, dicarboxylic acids and salts or anhydrides thereof; Salts or esters of aromatic sulfonic acids; Aromatic phosphonic acids, aromatic phosphonic acids, aromatic carboxylic acids or aluminum salts thereof; Aromatic metal phosphate; Alkyl alcohols having 8 to 30 carbon atoms; Condensates of polyhydric alcohols and aldehydes; Alkylamine; Chain polyolefin-based resin, and the like.

Among them, it is preferable to use a chain-like polyolefin-based resin, and from the viewpoints of the physical strength of the obtained base film 101 and the bleeding suppression of the nucleating agent, as a homopolymer or copolymer comprising an aliphatic monoolefin having 2 to 6 carbon atoms, It is more preferable to use a polymer having an average molecular weight of about 10,000 to 200,000 (preferably 20,000 to 150,000) and a high molecular weight. Specific examples of such a homopolymer or copolymer include homopolypropylene resin, low-density polyethylene resin, high-density polyethylene resin, copolymer resin of ethylene and? -Olefin having 4 to 6 carbon atoms, and ethylene-propylene copolymer resin.

Specific examples of the inorganic nucleating agent include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide; Alkali metal oxides such as sodium oxide; Alkali metal carbonates such as lithium carbonate, sodium carbonate, potassium carbonate, sodium hydrogencarbonate and potassium hydrogencarbonate; Alkaline earth metal hydroxides such as calcium hydroxide, magnesium hydroxide and barium hydroxide; Alkaline earth metal oxides such as calcium carbonate and calcium oxide, and the like.

It is of course possible to use a nucleating agent other than those exemplified above. The crude nucleating agent may be used alone, or two or more kinds may be used in combination.

The content of the nucleating agent is such that the degree of crystallization of the surface layer 101a can be 58% and the tensile modulus of the base film 101 at 80 캜 can be 140 MPa or more. If the content of the nucleating agent is too small, the base film 101 exhibiting a desired tensile modulus of elasticity can not be obtained. On the contrary, if too much, the stretchability of the laminated film 100 is lowered or bleeding of the nucleating agent occurs. Therefore, although it varies depending on the material of the thermoplastic resin film, the nucleating agent is preferably contained in a proportion of 0.1 to 10% by weight of the thermoplastic resin, more preferably in a proportion of 0.3 to 5% by weight.

As described above, the substrate film preparation step S10 may include both the heat treatment step S10-a and the nucleating agent addition step S10-b. The degree of crystallization and further the heat resistance of the base film 101 can be improved more efficiently by forming a thermoplastic resin film containing a nucleating agent on the surface layer and subjecting the thermoplastic resin film to a heat treatment at a predetermined temperature.

[2] Resin layer formation step S20

This step is a step of forming a polyvinyl alcohol resin layer 102 on at least one surface of the base film 101 to obtain a laminated film 100. As described above, the polyvinyl alcohol-based resin layer 102 can be formed by applying a coating solution containing a polyvinyl alcohol-based resin on one side or both sides of the base film 101 and drying the coated layer.

The coating liquid is preferably a polyvinyl alcohol resin solution obtained by dissolving a polyvinyl alcohol resin powder in a good solvent (e.g., water). Examples of the polyvinyl alcohol-based resin include a polyvinyl alcohol resin and derivatives thereof. Examples of derivatives of polyvinyl alcohol resins include polyvinyl formal, polyvinyl acetal, and the like. The polyvinyl alcohol resin may be mixed with an unsaturated carboxylic acid such as olefin such as ethylene or propylene, acrylic acid, methacrylic acid or crotonic acid, An alkyl ester of an acid, an acrylamide, and the like. Of the polyvinyl alcohol resins described above, polyvinyl alcohol resins are preferably used.

The average degree of polymerization of the polyvinyl alcohol resin is preferably 100 to 10,000, more preferably 1,000 to 10,000. In particular, it is more preferably from 1500 to 8000, and most preferably from 2000 to 5000. The average polymerization degree is a value obtained by a method determined by JIS K 6726 (1994). When the average degree of polymerization is less than 100, it is difficult to obtain the desired optical properties. If it exceeds 10000, the solubility in water deteriorates and it becomes difficult to form the resin layer.

The polyvinyl alcohol resin is preferably a saponified product. The degree of saponification is preferably 80.0 to 100.0 mol%, more preferably 90.0 to 99.5 mol%, and still more preferably 93.0 to 99.5 mol%. For example, a polyvinyl alcohol resin having a saponification degree of 98.0 to 99.5 mol% can be used. When the degree of saponification is less than 80.0 mol%, it is difficult to obtain the desired optical properties. The degree of saponification is a unit ratio (mol%) of a polyacetate resin which is a raw material of a polyvinyl alcohol-based resin and in which the acetic acid group is changed to a hydroxyl group by a saponification process.

Saponification degree (mol%) = (number of hydroxyl groups) / (number of hydroxyl groups + number of acetic acid groups) × 100

. It can be obtained by the method prescribed in JIS K 6726 (1994).

(Saponification degree: 98.0 to 99.0 mol%) and &quot; PVA117 &quot; (saponification degree: 98.0 to 99.0 mol%) manufactured by KURARAY CO., LTD are commercially available products of polyvinyl alcohol resins suitably usable. , &Quot; PVA117H &quot; (saponification degree: 99.5 mol% or more); AH-26 "(saponification degree: 97.0-98.8 mol%)," AH-22 "(saponification degree: 97.5-98.5 mol%)," NH- 98.0 to 99.0 mol%), "N-300" (saponification degree: 98.0 to 99.0 mol%); JC-33 "(saponification degree: not less than 99.0 mol%)," JP-45 "(saponification degree: 86.5 to 89.5 mol%) and" JF-17 "(saponification degree: 98.0 mol%) of Nippon Sakubi Poval Co., To 99.0 mol%), JF-17L (saponification degree: 98.0 to 99.0 mol%), and JF-20 (saponification degree: 98.0 to 99.0 mol%).

The coating liquid may contain an additive such as a plasticizer and a surfactant if necessary. As the plasticizer, a polyol or a condensate thereof can be used, and examples thereof include glycerin, diglycerin, triglycerin, ethylene glycol, propylene glycol, and polyethylene glycol. The blending amount of the additive is preferably 20% by weight or less of the polyvinyl alcohol resin.

The coating solution may be coated on the base film 101 by a roll coating method such as a wire bar coating method, a reverse coating method or a gravure coating method; Die coating method; Comma coat method; Lip coating method; Spin coating method; Screen coating method; Fountain coating method; Dipping method; Spray method, and the like.

The drying temperature and the drying time of the coating layer are set according to the type of the solvent contained in the coating liquid. The drying temperature is, for example, 50 to 200 占 폚, preferably 60 to 150 占 폚. When the solvent includes water, the drying temperature is preferably 80 DEG C or higher. The drying time is, for example, 2 to 20 minutes.

The surface of the base film 101 on the side where the polyvinyl alcohol resin layer 102 is formed is subjected to a corona treatment, a plasma treatment, a flame treatment, or the like to improve the adhesion with the polyvinyl alcohol resin layer 102 .

[3] Primer Layer Forming Process

As described above, in order to improve the adhesion between the base film 101 and the polyvinyl alcohol-based resin layer 102, it is preferable that between the base film preparation step S10 and the resin layer formation step S20, A step of forming a primer layer on the surface to which the liquid is applied may be set. The primer layer can be formed by coating a coating solution for forming a primer layer on the base film 101 and then drying it.

The coating solution for forming the primer layer is not particularly limited as long as it contains a material exhibiting a strong adhesion to the substrate film 101 and the polyvinyl alcohol resin layer 102 to some extent. The coating solution for forming a primer layer usually contains a resin component and a solvent which give such adhesion. As the resin component, a thermoplastic resin having excellent transparency, thermal stability, stretchability and the like is used, and examples thereof include (meth) acrylic resin, polyvinyl alcohol resin and the like. Among them, a polyvinyl alcohol-based resin which gives good adhesion is preferably used.

Examples of the polyvinyl alcohol-based resin include a polyvinyl alcohol resin and derivatives thereof. Examples of derivatives of polyvinyl alcohol resins include polyvinyl formal, polyvinyl acetal, and the like. The polyvinyl alcohol resin may be mixed with an unsaturated carboxylic acid such as olefin such as ethylene or propylene, acrylic acid, methacrylic acid or crotonic acid, An alkyl ester of an acid, an acrylamide, and the like. Of the polyvinyl alcohol resins described above, polyvinyl alcohol resins are preferably used.

As the solvent, an ordinary organic solvent or an aqueous solvent capable of dissolving the resin component is usually used. Examples of the solvent include aromatic hydrocarbons such as benzene, toluene and xylene; Ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; Esters such as ethyl acetate and isobutyl acetate; Chlorinated hydrocarbons such as methylene chloride, trichlorethylene, and chloroform; Ethanol, 1-propanol, 2-propanol, 1-butanol and the like. However, when a primer layer is formed using a coating solution for forming a primer layer containing an organic solvent, the base film 101 may be dissolved. Therefore, it is preferable to select a solvent in consideration of solubility of the film . In consideration of environmental influences, it is preferable to form a primer layer from a coating solution containing water as a solvent.

To increase the strength of the primer layer, a crosslinking agent may be added to the coating solution for forming a primer layer. The crosslinking agent is appropriately selected from among well-known ones such as an organic type and an inorganic type, depending on the type of the thermoplastic resin to be used. Examples of the crosslinking agent include epoxy-based, isocyanate-based, dialdehyde-based, and metal-based crosslinking agents. As the epoxy crosslinking agent, any one of a one-liquid curing type and a two-liquid curing type may be used, and ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin di or triglycidyl ether, Diol diglycidyl ether, trimethylol propane triglycidyl ether, diglycidyl aniline, diglycidyl amine, and the like.

Examples of the isocyanate crosslinking agent include tolylene diisocyanate, hydrogenated tolylene diisocyanate, trimethylolpropane-tolylene diisocyanate adduct, triphenylmethane triisocyanate, methylene bis (4-phenylmethane triisocyanate), isophorone diisocyanate, And isocyanates such as ketoxime block water and phenol block water.

Examples of dialdehyde crosslinking agents include glyoxal, malondialdehyde, succindialdehyde, glutaraldaldehyde, maleindialdehyde, phthalaldehyde and the like.

Examples of the metal-based crosslinking agent include metal salts, metal oxides, metal hydroxides, and organometallic compounds. Examples of the metal salt, metal oxide and metal hydroxide include divalent or more valent valences such as sodium, potassium, magnesium, calcium, aluminum, iron, nickel, zirconium, titanium, silicon, boron, zinc, copper, vanadium, chromium, Salts, oxides and hydroxides of the metals with which they have.

The organometallic compound is a compound having at least one structure in which an organic group is directly bonded to a metal atom or an organic group is bonded through an oxygen atom or a nitrogen atom. The organic group means a functional group containing at least a carbon element, and may be, for example, an alkyl group, an alkoxy group, an acyl group or the like. In addition, the term &quot; bond &quot; is not limited to a covalent bond, but may be a coordination bond by coordination of a chelate-type compound or the like.

Suitable examples of the organometallic compound include an organic titanium compound, an organic zirconium compound, an organoaluminum compound, and an organosilicon compound. The organometallic compound may be used alone, or two or more of them may be used in combination.

Examples of the organic titanium compound include titanium ortho esters such as tetra n-butyl titanate, tetraisopropyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, and tetramethyl titanate; Titanium chelates such as titanium acetylacetonate, titanium tetraacetylacetonate, polytitanacetylacetonate, titanium octylene glycolate, titanium lactate, titanium triethanolamine and titanium ethylacetoacetate; And titanium acylates such as polyhydroxytitanium stearate.

Examples of the organic zirconium compounds include zirconium n-propylate, zirconium n-butyrate, zirconium tetraacetylacetonate, zirconium monoacetylacetonate, zirconium bisacetylacetonate, zirconium acetylacetonate bis ethylacetoacetate and the like.

Examples of the organoaluminum compounds include aluminum acetylacetonate and aluminum organic acid chelate. As the organic silicon compound, for example, there can be mentioned a compound having a ligand exemplified in the above-mentioned organic titanium compound and organic zirconium compound.

In addition to the low molecular weight crosslinking agents described above, high molecular weight crosslinking agents such as methylol melamine resins and polyamide epoxy resins may also be used. Examples of commercially available products of polyamide epoxy resin include "Sumirei Resin 650 (30)" and "Sumirei Resin 675" (all trade names) sold by Taoka Chemical Industry Co., Ltd.

When a polyvinyl alcohol resin is used as the resin component of the primer layer, a polyamide epoxy resin, a methylol melamine resin, a dialdehyde crosslinking agent, a metal chelate compound crosslinking agent and the like are particularly preferable.

The ratio of the resin component and the crosslinking agent in the coating solution for forming a primer layer may be appropriately determined according to the kind of the resin component, the kind of the crosslinking agent and the like, in the range of about 0.1 to 100 parts by weight of the crosslinking agent relative to 100 parts by weight of the resin component, It is preferably selected in the range of about 0.1 to 50 parts by weight. The coating solution for forming a primer layer preferably has a solid concentration of about 1 to 25% by weight.

The thickness of the primer layer is preferably 0.05 to 1 mu m, more preferably 0.1 to 0.4 mu m. If the thickness is smaller than 0.05 탆, the effect of improving the adhesion between the base film 101 and the polyvinyl alcohol resin layer 102 is small, and if it is thicker than 1 탆, it is disadvantageous for thinning of the polarizing laminated film or polarizing plate.

The method of coating the primer layer-forming coating solution on the base film 101 may be the same as the coating solution for forming the polyvinyl alcohol-based resin layer. The primer layer is applied to the surface (one side or both sides of the base film 101) onto which the coating liquid for forming the polyvinyl alcohol-based resin layer is coated. The drying temperature and the drying time of the coating layer composed of the coating solution for forming the primer layer are set in accordance with the type of the solvent contained in the coating solution. The drying temperature is, for example, 50 to 200 占 폚, preferably 60 to 150 占 폚. When the solvent includes water, the drying temperature is preferably 80 DEG C or higher. The drying time is, for example, 30 seconds to 20 minutes.

[4] Stretching step S30

This step is a step of uniaxially stretching a laminated film 100 made of a base film 101 and a polyvinyl alcohol resin layer 102 to obtain a drawn film 200 (see Fig. 2). The stretching magnification of the laminated film 100 can be appropriately selected according to the desired polarization characteristics, but is preferably 5 times or more and 17 times or less, and more preferably 5 times or more than 8 times the original length of the laminated film 100 Times. If the stretching magnification is 5 times or less, the degree of polarization of the polarizing layer 302 obtained through the dyeing step S40 may not be sufficiently increased because the polyvinyl alcohol resin layer 102 is not sufficiently oriented. On the other hand, if the stretching magnification exceeds 17 times, the film tends to be broken at the time of stretching, and the thickness of the stretched film 200 becomes thinner than necessary, which may lower the workability and handling property in the subsequent step .

The stretching treatment is not limited to stretching in one stage but may be performed in multiple stages. In this case, all of the multistage stretching process may be performed continuously before the staining process S40, and the second and subsequent stretching processes may be performed simultaneously with the staining process and / or the crosslinking process in the staining process S40. In such a multi-stage stretching process, it is preferable that the stretching process is carried out so that the total of the front ends of the stretching process is greater than 5 times.

The stretching treatment may be longitudinal stretching in which stretching is performed in the longitudinal direction of the film (film transport direction), transverse stretching or oblique stretching in stretching in the film width direction, or the like. Examples of the longitudinal stretching method include inter-roll stretching, compression stretching and the like, and the transverse stretching method includes a tenter method and the like. Any of the wet drawing method and the dry drawing method can be employed as the drawing treatment, but a dry drawing method is preferable because the drawing temperature can be selected from a wide range.

The stretching temperature is set to be equal to or higher than the temperature at which the entirety of the polyvinyl alcohol resin layer 102 and the substrate film 101 can be stretched to exhibit fluidity and is preferably set at a temperature at which the base film 101 has a phase transition temperature Temperature to -30 deg. C, more preferably -30 deg. C to +5 deg. C, and still more preferably -25 deg. C to +0 deg. When the base film 101 is composed of a plurality of resin layers, the phase transition temperature means the highest phase transition temperature among the melting points indicated by the plurality of resin layers.

When the stretching temperature is lower than -30 캜 of the phase transition temperature, it is difficult to attain a high magnification stretching exceeding 5 times. If the stretching temperature exceeds +30 DEG C of the phase transition temperature, the fluidity of the base film 101 is too large and the stretching tends to become difficult. The stretching temperature is within the above range and more preferably 120 DEG C or more in that it is easier to achieve a high draw ratio of more than 5 times. When the stretching temperature is 120 ° C or higher, even if the stretching ratio is higher than 5 times, there is no difficulty in stretching treatment. The temperature adjustment of the stretching treatment is usually performed by adjusting the temperature of the heating furnace.

[5] Dyeing process S40

In this step, the polyvinyl alcohol resin layer 202 of the stretched film 200 is dyed with a dichroic dye, and the dye is adsorbed and aligned to form a polarizer layer 302. The polarizing layer 302 is laminated on one side or both sides of the base film 301 through this step, and the polarizing laminated film 300 is obtained (see Fig. 3).

Examples of the dichroic dye include iodine and organic dyes. Specific examples of the organic dyes include red BR, red LR, red R, pink LB, rubin BL, Borde GS, sky blue LG, lemon yellow, blue BR, blue 2R, navy RY, green LG, violet LB, B, Black H, Black B, Black GSP, Yellow 3G, Yellow R, Orange LR, Orange 3R, Scarlet GL, Scarlet KGL, Congo Red, Brilliant Violet BK, Supra Blue G, Supra Blue GL, Supra Orange GL, Blue, direct fast orange S, fast black, and the like. The dichroic dye may be used alone, or two or more dichroic dyes may be used in combination.

The dyeing step can be carried out by immersing the entire stretched film 200 in a solution (dyeing solution) containing a dichroic dye. As the dyeing solution, a solution obtained by dissolving the dichroic dye in a solvent may be used. As the solvent for the dyeing solution, water is generally used, but an organic solvent having compatibility with water may be further added. The concentration of the dichroic dye is preferably 0.01 to 10% by weight, more preferably 0.02 to 7% by weight, and still more preferably 0.025 to 5% by weight.

When iodine is used as the dichroic dye, it is preferable to add iodide to the dyeing solution containing iodine in that the dyeing efficiency can be further improved. Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide and titanium iodide. The concentration of iodide in the dyeing solution is preferably 0.01 to 20% by weight. Among iodides, it is preferable to add potassium iodide. When potassium iodide is added, the ratio of iodine to potassium iodide is preferably in the range of 1: 5 to 1: 100, more preferably in the range of 1: 6 to 1:80, more preferably 1: More preferably in the range of 7 to 1:70.

The immersion time of the stretched film 200 to the dyeing solution is usually in the range of 15 seconds to 15 minutes and preferably 20 seconds to 6 minutes. The temperature of the dyeing solution is preferably in the range of 10 to 60 占 폚, and more preferably in the range of 20 to 40 占 폚.

It is also possible to carry out the dyeing step S40 before or simultaneously with the stretching step S30, but it is also possible to carry out at least a part of the stretching treatment in the stretching step S30 so that the dichroic dye adsorbed to the polyvinyl alcohol- It is preferable to carry out the dyeing step S40 later. An embodiment in this case is a mode in which 1) a drawing process is performed at a target magnification and then a dyeing process S40 is performed without a drawing process, 2) a drawing process is performed at a magnification lower than the target, An aspect in which the stretching treatment is carried out so that the total magnification becomes the target magnification during the dyeing treatment in S40 (the dyeing step S40 includes a crosslinking treatment step, the dyeing treatment and / or the crosslinking treatment), 3) After the treatment, the stretching process is performed until the total magnification does not reach the target magnification during the dyeing process in the dyeing process S40 (in the case where the dyeing process S40 includes the crosslinking process, the dyeing process and / or the crosslinking process) And a drawing process is carried out so that the total magnification becomes the target magnification.

The dyeing step S40 may include a crosslinking treatment step which is carried out subsequent to the dyeing treatment. The crosslinking treatment can be carried out by immersing the dyed film in a solution (crosslinking solution) containing a crosslinking agent. As the crosslinking agent, conventionally known materials can be used, and examples thereof include boron compounds such as boric acid and borax, glyoxal, and glutaraldehyde. The crosslinking agent may be used alone or in combination of two or more.

Specifically, the crosslinking solution may be a solution in which a crosslinking agent is dissolved in a solvent. As the solvent, for example, water may be used, but it may further include an organic solvent compatible with water. The concentration of the crosslinking agent in the crosslinking solution is preferably in the range of 1 to 20 wt%, and more preferably in the range of 5 to 15 wt%.

The crosslinking solution may comprise iodide. By adding iodide, the polarization characteristics in the plane of the polarizer layer 302 can be made more uniform. Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide and titanium iodide. The concentration of iodide in the crosslinking solution is preferably 0.05 to 15% by weight, more preferably 0.5 to 8% by weight.

The immersing time of the dyed film to the crosslinking solution is usually 15 seconds to 20 minutes, preferably 30 seconds to 15 minutes. The temperature of the crosslinking solution is preferably in the range of 10 to 80 캜.

The crosslinking treatment may be carried out simultaneously with the dyeing treatment by blending the crosslinking agent into the dyeing solution. Further, a part of the crosslinking treatment and the stretching treatment may be performed at the same time. The specific embodiment in which the stretching treatment is carried out during the crosslinking treatment is as described above.

After the dyeing step S40, it is preferable to carry out a cleaning step and a drying step before the bonding step S50 to be described later. The cleaning process usually includes a water cleaning process. The water washing treatment can be performed by immersing the film after the dyeing treatment or the crosslinking treatment on pure water such as ion-exchanged water or distilled water. The water washing temperature is usually in the range of 3 to 50 캜, preferably 4 to 20 캜. The immersion time for water is usually from 2 to 300 seconds, preferably from 3 to 240 seconds.

The cleaning step may be a combination of a water cleaning step and a cleaning step with an iodide solution. In addition to water, a liquid alcohol such as methanol, ethanol, isopropyl alcohol, butanol, or propanol may suitably be contained in the washing liquid used in the water washing step and / or the washing treatment with the iodide solution.

As the drying step performed after the cleaning step, any suitable method such as natural drying, air blow drying, and heat drying can be employed. For example, in the case of heat drying, the drying temperature is usually 20 to 95 占 폚, and the drying time is usually about 1 to 15 minutes. The polarizing laminated film 300 obtained as described above can be used as a polarizing element as it is, and is also useful as an intermediate for producing a polarizing plate composed of the polarizing layer 302 and a protective film.

&Lt; Polarizing plate production method >

The method for producing a polarizing plate of the present invention comprises the steps of preparing the above-described polarizing laminated film 300, a joining step S50 for obtaining a bonded film by bonding a protective film on the polarizer layer 302 of the polarizing laminated film 300 And a peeling step S60 for peeling off the base film 301 from the bonded film in this order.

[6] Bonding Step S50

This step is a step of bonding a protective film to the polarizer layer 302 of the polarizing laminated film 300 to obtain a bonded film. The protective film can be bonded to the polarizer layer 302 using an adhesive or a pressure-sensitive adhesive. When the polarizing laminated film 300 has polarizer layers 302 on both sides of the base film 301, a protective film is usually bonded onto the polarizer layers 302 on both sides. In this case, these protective films may be the same kind of protective film or different kinds of protective films.

(Protective film)

Examples of the protective film include polyolefin-based resins such as a chain-like polyolefin-based resin (polypropylene-series resin and the like) and a cyclic polyolefin-series resin (norbornene-series resin and the like); Cellulose ester-based resins such as cellulose triacetate and cellulose diacetate; Polyester resins such as polyethylene terephthalate, polyethylene naphthalate and polybutylene terephthalate; Polycarbonate resin; (Meth) acrylic resins; Or a mixture or copolymer thereof, or the like. Examples of usable commercially available products such as a cyclic polyolefin resin and a film thereof, and cellulose triacetate are as described above.

The protective film may be a protective film having optical functions such as a retardation film and a brightness enhancement film. For example, a phase difference film having an arbitrary retardation value can be obtained by stretching a resin film made of the above material (such as uniaxial stretching or biaxial stretching) or forming a liquid crystal layer or the like on the film.

On the surface of the protective film opposite to the polarizer layer 302, an optical layer such as a hard coat layer, an antiglare layer, or an antireflection layer may be formed. Methods for forming these optical layers on the surface of the protective film are not particularly limited, and known methods can be used. The optical layer may be formed in advance on the protective film before the bonding step S50 is performed, or may be formed after the bonding step S50 or after the peeling step S60 described below.

A corona treatment, an ultraviolet ray irradiation treatment, a flame (flame) treatment, a saponification treatment, or the like is performed on the surface of the protective film on the side of the polarizer layer 302 in order to improve the adhesion with the polarizer layer 302 through an adhesive or a pressure- (Easy adhesion treatment) can be carried out. Among them, it is preferable to perform the corona treatment and the saponification treatment. For example, when the protective film is made of a cyclic polyolefin-based resin, a plasma treatment or a corona treatment is usually carried out. In the case of a cellulose ester resin, the saponification treatment is usually carried out. As the saponification treatment, a method of immersing in an aqueous alkaline solution such as sodium hydroxide or potassium hydroxide may be mentioned.

The thickness of the protective film is preferably small, but if it is too thin, the strength is lowered and the workability is poor. On the other hand, if the thickness is excessively large, there arises a problem that the transparency is lowered or the curing time required after bonding is lengthened. Therefore, the thickness of the protective film is preferably 90 占 퐉 or less, and more preferably 5 to 60 占 퐉. From the viewpoint of thinning of the polarizing plate, the total thickness of the polarizing layer 302 and the protective film is preferably 100 占 퐉 or less, more preferably 90 占 퐉 or less, further preferably 80 占 퐉 or less.

(glue)

As the adhesive, an aqueous adhesive or a photo-curing adhesive can be used. Examples of the water-based adhesive include an adhesive composed of a polyvinyl alcohol resin aqueous solution, an aqueous two-component type emulsion adhesive, and the like. Particularly when a cellulose ester based resin film that has been subjected to surface treatment (hydrophilization treatment) by a saponification treatment or the like is used as a protective film, it is preferable to use an aqueous adhesive composed of a polyvinyl alcohol resin aqueous solution.

Examples of the polyvinyl alcohol-based resin include a polyvinyl alcohol-based resin obtained by saponifying a copolymer of vinyl acetate and another monomer copolymerizable therewith, in addition to a vinyl alcohol homopolymer obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate A copolymer or a modified polyvinyl alcohol polymer obtained by partially modifying a hydroxyl group thereof can be used. The water-based adhesive may include additives such as polyvalent aldehyde, water-soluble epoxy compound, melamine compound, zirconia compound, and zinc compound. When an aqueous adhesive is used, the thickness of the adhesive layer obtained therefrom is usually 1 m or less.

An aqueous adhesive is coated on the polarizer layer 302 of the polarizing laminated film 300 and / or on a protective film, and these films are bonded together through an adhesive layer, preferably by pressurization using a bonding roll or the like A bonding process is performed. The coating method of the water-based adhesive (the same applies to the photo-curable adhesive) is not particularly limited, and the coating method such as a softening method, a Meyer bar coating method, a gravure coating method, a comma coater method, a doctor plate method, a die coating method, a dip coating method, Conventionally known methods can be used.

In the case of using the water-based adhesive, it is preferable to carry out the drying step of drying the film to remove the water contained in the water-based adhesive after the above-described bonding. Drying can be performed, for example, by introducing a film into a drying furnace. The drying temperature (temperature of the drying furnace) is preferably 30 to 90 占 폚. If it is less than 30 ° C, the protective film tends to be easily peeled off from the polarizer layer 302. If the drying temperature exceeds 90 ° C, the polarizing performance may be deteriorated by heat. The drying time can be 10 to 1000 seconds, and from the viewpoint of productivity, it is preferably 60 to 750 seconds, and more preferably 150 to 600 seconds.

After the drying step, a curing step may be performed in which the substrate is cured at a room temperature or a slightly higher temperature, for example, at a temperature of about 20 to 45 DEG C for about 12 to 600 hours. The curing temperature is generally set to be lower than the drying temperature.

The photo-curable adhesive refers to an adhesive that is cured by irradiating an active energy ray such as ultraviolet rays. Examples of the adhesive include a polymerizable compound and a photopolymerization initiator, a photoreactive resin, a binder resin and a photoreactive crosslinking agent And the like. Examples of the polymerizable compound include photopolymerizable monomers such as a photocurable epoxy monomer, a photocurable acrylic monomer and a photocurable urethane monomer, and oligomers derived from a photopolymerizable monomer. Examples of the photopolymerization initiator include those which generate active species such as neutral radicals, anion radicals, and cation radicals upon irradiation with active energy rays such as ultraviolet rays. As the photo-curable adhesive containing a polymerizable compound and a photopolymerization initiator, those containing a photo-curable epoxy monomer and a photo cationic polymerization initiator can be preferably used.

In the case of using a photo-curing adhesive, a curing step of curing the photo-curing adhesive by irradiating active energy rays after the bonding as described above and then performing a drying step (if the photo-curable adhesive contains a solvent) . The light source of the active energy ray is not particularly limited, but an active energy ray having a light emission distribution at a wavelength of 400 nm or less is preferable. Specifically, a low energy mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, Mercury lamp, metal halide lamp and the like are preferably used.

The light irradiation intensity for the photo-curable adhesive is preferably determined according to the composition of the photo-curable adhesive and is preferably set so that the irradiation intensity in the wavelength range effective for activating the polymerization initiator is 0.1 to 6000 mW / cm &lt; ² &gt;. When the irradiation intensity is not less than 0.1 mW / cm ² , the reaction time is not excessively long. When the irradiation intensity is 6000 mW / cm ² or less, the heat radiated from the light source and the yellowing of the photocurable adhesive due to heat generation during curing of the photo- It is less likely to cause deterioration of the layer 302.

As for the light irradiation time for the photo-curing adhesive, and properly determined depending on the composition of the photo-curing adhesive, it is preferred that the accumulated light quantity to be displayed as the product of the irradiation intensity and the irradiation time is set so that 10~10000 mJ / cm ² . When the accumulated light quantity is 10 mJ / cm ² or more, a sufficient amount of active species originating from the polymerization initiator can be sufficiently generated to allow the curing reaction to proceed more surely. When the total light quantity is 10,000 mJ / cm ² or less, the irradiation time is not excessively long, Lt; / RTI &gt;

The thickness of the adhesive layer after irradiation with active energy rays is usually about 0.001 to 5 mu m, preferably 0.01 to 2 mu m, more preferably 0.01 to 1 mu m.

(adhesive)

The pressure-sensitive adhesive to be used for bonding the protective film is usually composed of a base polymer and a crosslinking agent such as an isocyanate compound, an epoxy compound, or an aziridine compound added thereto, such as an acrylic resin, a styrene resin or a silicone resin. It is also possible to use a pressure-sensitive adhesive layer containing fine particles and exhibiting light scattering properties.

The thickness of the pressure-sensitive adhesive layer may be 1 to 40 占 퐉, but it is preferable that the pressure-sensitive adhesive layer is thinly coated within a range not deteriorating the workability and durability characteristics, and more preferably 3 to 25 占 퐉. 3 to 25 [micro] m, and has a suitable thickness for suppressing the dimensional change of the polarizer layer 302. [ When the pressure-sensitive adhesive layer is less than 1 탆, the pressure-sensitive adhesive property is deteriorated. When the pressure-sensitive adhesive layer is more than 40 탆, the pressure-sensitive adhesive is liable to be discharged. In the method of bonding the protective film to the polarizer layer 302 by using the pressure-sensitive adhesive, a pressure-sensitive adhesive layer may be formed on the protective film surface and then bonded to the polarizer layer 302. Alternatively, After forming, a protective film may be bonded to this place.

The method of forming the pressure-sensitive adhesive layer is not particularly limited, and a pressure-sensitive adhesive solution containing each component including the above-mentioned base polymer may be coated on the surface of the protective film or polarizer layer 302 and dried to form a pressure- The protective film and the polarizer layer 302 may be bonded together and the pressure-sensitive adhesive layer may be transferred onto the protective film surface or the surface of the polarizer layer 302 after the pressure-sensitive adhesive layer is formed on the separator, May be joined to each other. When the pressure-sensitive adhesive layer is formed on the protective film surface or the surface of the polarizer layer 302, surface treatment such as corona treatment or the like is performed on the protective film surface or the polarizer layer 302 side or the pressure- It is also good.

[7] Peeling step S60

This step is a step of peeling off the base film 301 from a bonding film obtained by bonding a protective film. Through this process, a polarizing plate in which a protective film is laminated on the polarizer layer 302 can be obtained. When the polarizing laminated film 300 has polarizer layers 302 on both sides of the base film 301 and a protective film is bonded to both of these polarizer layers 302 in this peeling step S60, A polarizing plate is obtained.

The method of peeling off the base film 301 is not particularly limited, and can be peeled off in the same manner as the peeling process of a separator (peeling film) which is performed in a usual polarizing plate with a pressure-sensitive adhesive. The base film 301 may be peeled immediately after the joining step S50, or may be peeled off in a subsequent step after peeling off the joining step S50.

The polarizing plate produced as described above can be used as an optical film in which other optical layers are laminated in practice. Further, the protective film may have the function of such an optical layer. Other optical layers include a reflective polarizing film that transmits polarized light of any kind and reflects polarized light exhibiting properties opposite to that of the polarized light; An anti-glare function imparting film having a concavo-convex shape on its surface; A surface antireflection function imparting film; A reflecting film having a reflecting function on the surface; A transflective film having a reflection function and a transmission function; And a viewing angle compensation film.

As a commercially available product corresponding to a reflection type polarizing film that transmits polarized light of any kind and reflects polarized light exhibiting a property opposite to that of the polarized light, for example, "DBEF" (manufactured by 3M, Sumitomo 3M Ltd.) APF &quot; (available from 3M, available from Sumitomo 3M Ltd.).

Examples of the viewing angle compensation film include an optical compensation film on which a liquid crystal compound is coated and oriented on a substrate surface, a retardation film made of a polycarbonate resin, and a retardation film made of a cyclic polyolefin resin.

"WV film" (manufactured by Fuji Film Co., Ltd.), "NH film" (manufactured by Shin-Nippon Petrochemical Co., Ltd.), and commercially available products such as " Quot; NR film &quot; (manufactured by Shin-Nippon Petrochemical Co., Ltd.).

Examples of commercially available products corresponding to the retardation film made of the cyclic polyolefin resin include "Aton film" (manufactured by JSR Corporation), "Essen" (manufactured by Sekisui Chemical Co., Ltd.), "Zeonoah Film" (Manufactured by Zeon Corporation).

Example

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the examples, the tensile modulus of the film at 80 ° C and the degree of crystallization of the film surface layer were determined by the following methods.

&Lt; Tensile modulus at 80 ° C>

A rectangular test piece having a length of 100 mm and a width of 40 mm was cut out in the longitudinal direction of the film MD and measured using an autograph AG-I universal testing machine manufactured by Shimadzu Corporation. The tester has a detachable thermostat. First, the thermostatic chamber in the testing machine was set at 80 DEG C, and the direction of the test piece was set to be 100 mm in the tensile direction. The initial chuck distance was held at 80 mm and maintained for 1 hour or longer. , And a tensile test was conducted at a tensile rate of 30 mm / min to calculate the tensile modulus of elasticity.

&Lt; Crystallinity of film surface layer >

The infrared spectroscopic spectrum of the surface layer of the film was obtained by the following specifications and measurement procedure using the following apparatus. From the infrared spectroscopic spectrum,

Crystallinity X (%) = 109 x (A ₉₉₈ -A ₉₂₀ ) / (A ₉₇₄ -A ₉₂₀ ) -31.4

(A ₉₉₈ , A ₉₇₄ and A ₉₂₀ in the formula are the same as defined above.)

The crystallinity X was calculated.

Apparatus: Brown-Fourier Transform Infrared Spectrophotometer "FTS-7000 / UMA600 (brown rice unit)" manufactured by Agilent,

Measurement mode: ATR method (prism: Ge, incidence angle: 30 °),

Resolution: 4 cm ^-1 ,

· Number of integrations: 128 times,

ATR-IR measurement procedure: The surface of a base film made of a polypropylene type multi-layer film was directly pressed onto a Ge (germanium) crystal prism to obtain an infrared spectral spectrum.

&Lt; Example 1 >

(1) Production of base film

A homopolymer of propylene (hereinafter referred to as &quot; propylene homopolymer &quot;) was laminated on both sides of a resin layer composed of a random copolymer of propylene / ethylene containing about 5% by weight of ethylene unit (&quot; Sumitomonoburen W151 &quot; A long polypropylene multi-layer film having a three-layer structure in which a resin layer composed of homopolypropylene (Sumitomo nobulene FLX80E4, manufactured by Sumitomo Chemical Co., Ltd., melting point Tm = 163 ° C) Extrusion molding. The total thickness of the polypropylene multilayer films was 100 占 퐉, and the thickness ratio (FLX80E4 / W151 / FLX80E4) of each layer was 3/4/3.

Next, the polypropylene multi-layer film was subjected to heat treatment. Concretely, the polypropylene multilayer film was first brought into contact with the hot roll at 70 ° C for about 10 seconds while carrying the polypropylene multilayer film (the first stage of the heat treatment), and then heated in an oven at 80 ° C for 1 minute Deg.] C for 1 minute (third stage of the heat treatment), and subjected to heat treatment to obtain a base film. The maximum temperature for the heat treatment in this heat treatment step is 100 캜 in the third stage. With respect to this base film, the tensile modulus at 80 캜 and the degree of crystallization of the surface layer were determined, and the results shown in Table 1 were obtained.

(2) Formation of primer layer and polyvinyl alcohol-based resin layer (production of laminated film)

Polyvinyl alcohol powder ("Z-200" manufactured by Nippon Gosei Chemical Industry Co., Ltd., average polymerization degree: 1100, average saponification degree: 99.5 mol%) was dissolved in hot water at 95 ° C to prepare a polyvinyl alcohol aqueous solution having a concentration of 3% It was prepared. A crosslinking agent (&quot; Sumireze Resin 650 &quot;, manufactured by Taoka Chemical Co., Ltd.) was added to the obtained aqueous solution at a ratio of 1 part by weight based on 2 parts by weight of the solid content of polyvinyl alcohol to obtain a coating solution for forming a primer layer.

Further, polyvinyl alcohol powder ("PVA 124" manufactured by Kuraray Co., Ltd., average degree of polymerization: 2400, average degree of saponification: 98.0 to 99.0 mol%) was dissolved in hot water at 95 ° C to prepare a polyvinyl alcohol aqueous solution To prepare a coating solution for forming a polyvinyl alcohol-based resin layer.

Next, a corona treatment was performed on one surface of the substrate film while the substrate film subjected to the heat treatment in the above (1) was continuously conveyed. Subsequently, on the surface subjected to the corona treatment, the coating solution for the primer layer Followed by drying at 80 캜 for 3 minutes to form a primer layer having a thickness of 0.2 탆. Subsequently, the coating solution for forming the polyvinyl alcohol-based resin layer was continuously coated on the primer layer by using a comma coater while conveying the film, and the coating was carried out at 90 DEG C for 1 minute, at 70 DEG C for 3 minutes, Lt; 0 &gt; C for 4 minutes to form a polyvinyl alcohol-based resin layer having a thickness of 10.0 mu m on the primer layer to obtain a laminated film.

The maximum temperature at the time of drying in the primer layer forming step is 80 占 폚 as described above, and the maximum temperature at the time of drying in the resin layer forming step is 90 占 폚. No defects such as wrinkles or folding occurred in any of the base films in any drying process, and drying was possible without any problem.

(3) Production of stretched film

While the laminated film obtained in the above (2) was continuously conveyed, free uniaxial stretching was performed at a stretching temperature of 160 캜 at a magnification ratio of 5.8 times in the longitudinal direction (film conveying direction) Film. The thickness of the polyvinyl alcohol-based resin layer in the stretched film was 5.0 mu m. No particular problems were found in the stretching treatment.

(4) Production of a polarizing laminated film

While the stretched film obtained in the above (3) was continuously conveyed, it was immersed in a hot water bath at 60 ° C for a retention time of 60 seconds, then immersed in a dyeing solution at 30 ° C containing iodine and potassium iodide for about 150 seconds So that the polyvinyl alcohol resin layer was dyed, and then the excess dyeing solution was washed with pure water at 10 占 폚. Subsequently, the substrate was immersed in a crosslinked solution at 76 DEG C containing boric acid and potassium iodide so that the residence time would be 600 seconds, and crosslinking treatment was carried out. Thereafter, the film was washed with pure water at 10 캜 for 4 seconds and dried at 80 캜 for 300 seconds to obtain a polarizing laminated film.

(5) Production of Polarizing Plate

A polyvinyl alcohol aqueous solution having a concentration of 3% by weight was prepared by dissolving polyvinyl alcohol powder ("KL-318" manufactured by Kuraray Co., Ltd., average degree of polymerization: 1800) in hot water at 95 ° C. A crosslinking agent (&quot; Sumireze Resin 650 &quot;, manufactured by Taoka Chemical Co., Ltd.) was mixed in the resulting aqueous solution at a ratio of 1 part by weight based on 2 parts by weight of the solid content of polyvinyl alcohol, to obtain an adhesive solution.

Next, while the polarizing laminated film obtained in the above (4) was continuously conveyed, the adhesive solution was coated on the polarizer layer, and then a triacetylcellulose (TAC) film (Konica Minolta Opto (KC4UY, thickness: 40 mu m) was adhered to the adhesive solution coating surface on the polarizer layer and passed between a pair of bonding rolls to obtain a bonded film. Subsequently, the base film was peeled off from the bonding film to obtain a polarizing plate in which a protective film made of a TAC film was laminated on the polarizer layer through an adhesive layer. At this time, the base film was easily peeled off.

&Lt; Example 2 >

(1) Production of base film

A substrate film was obtained in the same manner as in (1) of Example 1, except that the polypropylene multi-layer film was conveyed while being heated by contacting the hot roll at 90 占 폚 for about 10 seconds. In this heat treatment process, the heat treatment operation is only one stage by the heating roll, and the maximum temperature of the heat treatment is 90 deg. With respect to this base film, the tensile modulus at 80 캜 and the degree of crystallization of the surface layer were determined, and the results shown in Table 1 were obtained.

(2) Formation of primer layer and polyvinyl alcohol-based resin layer (production of laminated film)

(2) of Example 1, except that a corona treatment was applied to both surfaces of the substrate film subjected to the heat treatment in the above (1), and a primer layer and a polyvinyl alcohol-based resin layer were formed on both surfaces, respectively To obtain a laminated film. The thicknesses of the primer layer and the polyvinyl alcohol-based resin layer formed on one side were 0.2 탆 and 10.5 탆, respectively, and the thicknesses of the primer layer and the polyvinyl alcohol-based resin layer formed on the other side were 0.2 탆 and 11.0 탆, respectively .

The maximum temperature at the time of drying in the primer layer forming step is 80 占 폚, and the maximum temperature at the time of drying in the resin layer forming step is 90 占 폚. No defects such as wrinkles or folding occurred in any of the base films in any drying process, and drying was possible without any problem.

(3) Production of stretched film and polarizing laminated film

Using the laminated film obtained in the above (2), a stretched film was produced in the same manner as in (3) of Example 1, and a polarizing laminated film was produced in the same manner as in the (4) The thickness of the polyvinyl alcohol-based resin layer on both sides of the stretched film was 5.0 mu m and 5.6 mu m, respectively. No particular problems were found in the stretching treatment.

(4) Production of Polarizer

A bonded film was produced in the same manner as in (5) of Example 1, except that the polarizing laminated film prepared in (3) above was used to adhere a protective film to each polarizing layer on both sides. Subsequently, the base film was peeled off from the bonding film to obtain two polarizing plates in which a protective film was laminated on the polarizer layer through an adhesive layer. At this time, the base film was easily peeled off.

&Lt; Example 3 >

(1) Production of base film

Except that the polypropylene multilayer film was brought into contact with the hot roll at 90 占 폚 for about 7 seconds (the first stage of the heat treatment), and the second heat treatment was then carried out for 2 minutes in the oven at 100 占 폚 , And (1) in Example 2, a base film was produced. The maximum temperature for the heat treatment in this heat treatment step is 100 캜 at the second stage. With respect to this base film, the tensile modulus at 80 캜 and the degree of crystallization of the surface layer were determined, and the results shown in Table 1 were obtained.

(2) Formation of primer layer and polyvinyl alcohol-based resin layer (production of laminated film)

A laminated film was obtained in the same manner as in (2) of Example 2 except that the substrate film subjected to the heat treatment in (1) above was used. The thicknesses of the primer layer and the polyvinyl alcohol-based resin layer formed on one side were 0.3 탆 and 10.5 탆, respectively, and the thicknesses of the primer layer and the polyvinyl alcohol-based resin layer formed on the other side were 0.2 탆 and 10.8 탆, respectively .

The maximum temperature at the time of drying in the primer layer forming step is 80 占 폚, and the maximum temperature at the time of drying in the resin layer forming step is 90 占 폚. No defects such as wrinkles or folding occurred in any of the base films in any drying process, and drying was possible without any problem.

(3) Production of stretched film and polarizing laminated film

A stretched film and a polarizing laminated film were produced in the same manner as in (3) of Example 2, using the laminated film obtained in the above (2). The thickness of the polyvinyl alcohol-based resin layer on both sides of the drawn film was 5.1 占 퐉 and 5.5 占 퐉, respectively. No particular problems were found in the stretching treatment.

(4) Production of Polarizer

A bonded film was prepared in the same manner as in (4) of Example 2 except that the polarizing laminated film prepared in (3) above was used, and the base film was peeled off therefrom to form an adhesive layer To obtain two polarizing plates each having a protective film laminated thereon. At this time, the base film was easily peeled off.

<Example 4>

(1) Production of base film

A substrate film was produced in the same manner as in (2) of Example 2 except that the polypropylene multi-layer film was conveyed while being heated in an oven at 110 캜 for 2 minutes. In this heat treatment process, the heat treatment operation is only one stage by the oven, and the maximum temperature of the heat treatment is 110 deg. With respect to this base film, the tensile modulus at 80 캜 and the degree of crystallization of the surface layer were determined, and the results shown in Table 1 were obtained.

(2) Formation of primer layer and polyvinyl alcohol-based resin layer (production of laminated film)

A laminated film was obtained in the same manner as in (2) of Example 2 except that the substrate film subjected to the heat treatment in (1) above was used. The thicknesses of the primer layer and the polyvinyl alcohol-based resin layer formed on one surface were 0.3 m and 10.7 m, respectively, and the thicknesses of the primer layer and the polyvinyl alcohol-based resin layer formed on the other surface were 0.3 m and 11.0 m, respectively .

The maximum temperature at the time of drying in the primer layer forming step is 80 占 폚, and the maximum temperature at the time of drying in the resin layer forming step is 90 占 폚. No defects such as wrinkles or folding occurred in any of the base films in any drying process, and drying was possible without any problem.

(3) Production of stretched film and polarizing laminated film

A stretched film and a polarizing laminated film were produced in the same manner as in (3) of Example 2, using the laminated film obtained in the above (2). The thickness of the polyvinyl alcohol-based resin layer on both sides of the stretched film was 5.2 mu m and 5.5 mu m, respectively. No particular problems were found in the stretching treatment.

(4) Production of Polarizer

A bonded film was prepared in the same manner as in (4) of Example 2 except that the polarizing laminated film prepared in (3) above was used, and the base film was peeled off therefrom to form an adhesive layer To obtain two polarizing plates each having a protective film laminated thereon. At this time, the base film was easily peeled off.

&Lt; Example 5 >

(1) Production of base film

3% by weight of a nucleating agent composed of high-density polyethylene was blended with homopolypropylene (Sumitomo noblean FLX80E4, manufactured by Sumitomo Chemical Co., Ltd., melting point Tm = 163 ° C) as a homopolymer of propylene, . This and the same propylene / ethylene random copolymer "Sumitomonoburen W151" as used in Example 1 (1) were co-extruded using a multilayer extrusion molding machine to obtain a resin layer made of "Sumitomonoburen W151" A long polypropylene multi-layer film having a three-layer structure in which a resin layer made of polypropylene containing the above nucleating agent was disposed was prepared on both sides of the base film. The total thickness of the base film was 100 占 퐉, and the thickness ratio (polypropylene / W151 containing a nucleating agent / polypropylene containing a nucleating agent) was 3/4/3. With respect to this base film, the tensile modulus at 80 캜 and the degree of crystallization of the surface layer were determined, and the results shown in Table 1 were obtained.

(2) Formation of primer layer and polyvinyl alcohol-based resin layer (production of laminated film)

A laminated film was obtained in the same manner as in (2) of Example 2 except that the base film produced in (1) above was used. The thicknesses of the primer layer and the polyvinyl alcohol-based resin layer formed on one side were 0.3 탆 and 11.1 탆, respectively, and the thicknesses of the primer layer and the polyvinyl alcohol-based resin layer formed on the other side were 0.3 탆 and 11.3 탆, respectively . No defects such as wrinkles and folding occurred in any of the base films in the drying step in the primer layer forming step and the resin layer forming step, and drying without problems could be performed.

(3) Production of stretched film and polarizing laminated film

A stretched film and a polarizing laminated film were produced in the same manner as in (3) of Example 2, using the laminated film obtained in the above (2). The thickness of the polyvinyl alcohol-based resin layer on both sides of the drawn film was 5.5 탆 and 5.6 탆, respectively. No particular problems were found in the stretching treatment.

(4) Production of Polarizer

A bonded film was prepared in the same manner as in (4) of Example 2 except that the polarizing laminated film prepared in (3) above was used, and the base film was peeled off therefrom to form an adhesive layer To obtain two polarizing plates each having a protective film laminated thereon. At this time, the base film was easily peeled off.

&Lt; Example 6 >

(1) Production of base film

A polypropylene multilayer film was produced in the same manner as in (5) of Example 5 except that the blending amount of the nucleating agent was changed to 1% by weight to obtain a base film. With respect to this base film, the tensile modulus at 80 캜 and the degree of crystallization of the surface layer were determined, and the results shown in Table 1 were obtained.

(2) Formation of primer layer and polyvinyl alcohol-based resin layer (production of laminated film)

A laminated film was obtained in the same manner as in (2) of Example 2 except that the base film produced in (1) above was used. The thicknesses of the primer layer and the polyvinyl alcohol-based resin layer formed on one side were 0.2 탆 and 10.1 탆, respectively, and the thicknesses of the primer layer and the polyvinyl alcohol-based resin layer formed on the other side were 0.3 탆 and 10.5 탆, respectively . No defects such as wrinkles and folding occurred in any of the base films in the drying step in the primer layer forming step and the resin layer forming step, and drying without problems could be performed.

(3) Production of stretched film and polarizing laminated film

A stretched film and a polarizing laminated film were produced in the same manner as in (3) of Example 2, using the laminated film obtained in the above (2). The thickness of the polyvinyl alcohol-based resin layer on both sides of the drawn film was 4.8 mu m and 5.1 mu m, respectively. No particular problems were found in the stretching treatment.

(4) Production of Polarizer

A bonded film was prepared in the same manner as in (4) of Example 2 except that the polarizing laminated film prepared in (3) above was used, and the base film was peeled off therefrom to form an adhesive layer To obtain two polarizing plates each having a protective film laminated thereon. At this time, the base film was easily peeled off.

&Lt; Comparative Example 1 &

(1) Production of base film

A substrate film was obtained in the same manner as in (1) of Example 1, except that the polypropylene multilayer film was transported while being heated by contact with hot roll at 70 占 폚 for about 10 seconds. In the present heat treatment process, the heat treatment operation is only one stage by the heating roll, and the maximum temperature of the heat treatment is 70 deg. With respect to this base film, the tensile modulus at 80 캜 and the degree of crystallization of the surface layer were determined, and the results shown in Table 1 were obtained.

(2) Formation of primer layer and polyvinyl alcohol-based resin layer (production of laminated film)

The substrate film subjected to the heat treatment in (1) above was continuously conveyed in the same manner as in (2) of Example 1, corona treatment was performed on one surface thereof, and a microgravure coater , The same primer layer coating solution as used in (2) of Example 1 was continuously coated and dried at 80 캜 for 3 minutes to form a primer layer. At the time of drying, the substrate film was wrinkled or folded. The wrinkles referred to here are fine gold generated by shrinkage of the surface of the base film by heat, and the wrinkles disappear when the film is drawn out of the line and stretched by hand. On the other hand, the folding is that the degree of folding is serious and the folding marks are completely folded, so that even if the film is drawn out of the line and handed, the folding marks do not disappear.

Subsequently, a coating solution for forming the same polyvinyl alcohol resin layer as used in (2) of Example 1 was continuously coated on the primer layer using a comma coater, and the coating was continuously applied at 80 DEG C for 4 minutes and then at 70 DEG C Lt; / RTI &gt; for 2 minutes. At this time, the coating liquid was concentrated on the corrugated portion, and the coating was dried at that portion. The maximum temperature during drying in the primer layer forming step and the resin layer forming step is all 80 ° C.

&Lt; Comparative Example 2 &

(1) Production of base film

The polypropylene multilayer film produced in (1) of Example 1 was used as the base film without heat treatment. With respect to this base film, the tensile modulus at 80 캜 and the degree of crystallization of the surface layer were determined, and the results shown in Table 1 were obtained.

(2) Formation of primer layer

The substrate film of (1) above was continuously conveyed in the same manner as in (2) of Example 1, and corona treatment was performed on one surface thereof. Subsequently, on the corona-treated surface, a microgravure coater was used, The same primer layer coating solution as used in (2) was continuously coated and dried at 80 DEG C for 3 minutes to form a primer layer. At this time, wrinkles or folding occurred in the substrate film during drying, and the coating liquid was solid at the folded portion, resulting in unevenness in thickness. Further, the corrugated portion caused a drying defect because the thickness of the coating liquid became large.

Yes No
Base film The drying temperature of the primer layer forming step
The maximum drying temperature of the resin layer forming process

Judgment

Heat treatment
(Temperature × time) Nucleating agent
Addition amount
Tensile rigidity at 80 ℃ Surface crystallinity potter


Heat roll Oven Example
One
70 ° C × 10 seconds 80 ° C × 1 minute
100 ° C × 1 minute - 192 Mpa 64.0% One side 80 ℃ 90 ° C OK Example
2 90 ° C × 10 seconds - - 155 Mpa 60.0% both sides 80 ℃ 90 ° C OK Example
3 90 ℃ × 7 seconds 100 ° C × 2 minutes - 228 Mpa 67.9% both sides 80 ℃ 90 ° C OK Example
4 - 110 ° C × 2 minutes - 223 Mpa 67.3% both sides 80 ℃ 90 ° C OK Example
5 - - 3 wt% 229 Mpa 67.6% both sides 80 ℃ 90 ° C OK Example
6 - - 1 wt% 209 Mpa 66.6% both sides 80 ℃ 90 ° C OK Comparative Example
One 70 ° C × 10 seconds - - 131 Mpa 57.4% section 80 ℃ 80 ℃ NG Comparative Example
2 - - - 123 Mpa 56.4% section 80 ℃ - NG

In Table 1, the meaning of "OK" and "NG" in the judgment column is as follows.

OK: The base film satisfies the requirements of the present invention, does not cause defects such as wrinkles and folds, can be dried without problems,

NG: The base film does not satisfy the requirements of the present invention, and wrinkles or folds occur during drying, resulting in drying failure.

100: laminated film
101: base film
101a: surface layer of base film
102: polyvinyl alcohol-based resin layer
200: stretched film
201: stretched substrate film
202: stretched polyvinyl alcohol-based resin layer
300: Polarizing laminated film
301: Base film after dyeing process
302: Polarizer layer.

Claims (13)

A base film made of a thermoplastic resin and a polyvinyl alcohol resin layer formed on at least one side of the base film by coating, wherein the base film has a tensile elastic modulus at 80 DEG C of 140 MPa or more. The substrate film according to claim 1, wherein the surface layer of the surface on which at least the polyvinyl alcohol-based resin layer is formed is made of a crystalline thermoplastic resin, and the surface layer composed of the crystalline thermoplastic resin has a crystallinity of at least 58% , Laminated film. The laminated film according to claim 2, wherein the surface layer composed of the crystalline thermoplastic resin of the base film contains a nucleating agent. The laminated film according to any one of claims 1 to 3, wherein the polyvinyl alcohol-based resin layer has a thickness of 3 to 30 탆. The method for producing a polarizing laminated film according to any one of claims 1 to 4, wherein the polyvinyl alcohol resin layer is uniaxially stretched while being a laminated film, and then a polarizer layer is formed by dying the polyvinyl alcohol resin layer with a dichroic dye, Gt; laminated film. &Lt; / RTI &gt; A stretched film obtained by uniaxially stretching the laminated film according to any one of claims 1 to 4 to obtain a stretched film,
A dyeing step of obtaining a polarizing laminated film by dying a polyvinyl alcohol-based resin layer of the resulting stretched film with a dichroic dye to form a polarizer layer
Wherein the polarizing film is a polarizing film. A base film preparation step of preparing a base film made of a thermoplastic resin film having a tensile elastic modulus at 80 DEG C of 140 MPa or more;
A resin layer forming step of forming a polyvinyl alcohol resin layer by coating a coating solution containing a polyvinyl alcohol resin on at least one surface of the base film and then drying the resin film to obtain a laminated film,
A stretching step of uniaxially stretching the obtained laminated film to obtain a stretched film,
A dyeing step of obtaining a polarizing laminated film by dying a polyvinyl alcohol-based resin layer of the resulting stretched film with a dichroic dye to form a polarizer layer
Wherein the polarizing film is a polarizing film. A base film preparation step of heating the thermoplastic resin film to obtain a base film;
A resin layer forming step of forming a polyvinyl alcohol resin layer by coating a coating solution containing a polyvinyl alcohol resin on at least one surface of the obtained base film and then drying the resin film to obtain a laminated film,
A stretching step of uniaxially stretching the obtained laminated film to obtain a stretched film,
A dyeing step of obtaining a polarizing laminated film by dying a polyvinyl alcohol-based resin layer of the resulting stretched film with a dichroic dye to form a polarizer layer
Wherein the base film preparation step includes a step of heat-treating the thermoplastic resin film at a temperature equal to or higher than the drying temperature in the resin layer formation step. 9. The method according to claim 8, wherein a primer layer is formed between the base film preparation step and the resin layer formation step by coating a coating solution for forming a primer layer on the surface of the base film on which the coating solution is coated, A primer layer forming step of forming a primer layer,
Wherein the base film preparation step includes a step of heat-treating the thermoplastic resin film at a temperature equal to or higher than the drying temperature in the step of forming the primer layer. A base film preparation step of preparing a base film made of a thermoplastic resin film wherein at least the surface layer of the surface on which the polyvinyl alcohol resin layer is formed in the next step is composed of a crystalline thermoplastic resin containing a nucleating agent,
A resin layer forming step of forming a polyvinyl alcohol resin layer by coating a coating solution containing a polyvinyl alcohol resin on at least one surface of the base film and then drying the resin film to obtain a laminated film,
A stretching step of uniaxially stretching the obtained laminated film to obtain a stretched film,
A dyeing step of obtaining a polarizing laminated film by dying a polyvinyl alcohol-based resin layer of the resulting stretched film with a dichroic dye to form a polarizer layer
Wherein the polarizing film is a polarizing film. 11. The method of producing a polarizing laminated film according to any one of claims 6 to 10, wherein the laminated film is uniaxially stretched at a draw magnification of more than 5 times. The method for producing a polarizing laminated film according to any one of claims 6 to 11, wherein the polyvinyl alcohol-based resin layer in the laminated film has a thickness of 3 to 30 탆. A method for producing a polarizing laminated film, comprising the steps of preparing a polarizing laminated film obtained by the production method according to any one of claims 6 to 12,
A step of bonding a protective film to the polarizer layer in the polarizing laminated film to obtain a bonded film,
A step of peeling the base film from the resulting bonded film
And a polarizing plate.

Images