JP2011248294A - Manufacturing method of polarizing laminated film and manufacturing method of polarizing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a polarizing laminated film allowing good control of split generation in a stretching direction in following steps even if a laminated film is stretched at a high stretch magnification in a uniaxial direction.SOLUTION: The manufacturing method of a polarizing laminated film of the present invention includes a first stretching step (S10) for stretching a base film in a width direction to obtain a stretched base film; a resin layer forming step (S20) for forming a resin layer comprising a polyvinyl alcohol resin on one face of the stretched base film to obtain a laminated film; a second stretching step (S30) for uniaxially stretching the laminated film in a flow direction to obtain a stretched laminated film; and a dyeing step (S40) for forming a polarizer layer by dyeing the above resin layer of the stretched laminated film with a dichroic pigment to obtain a polarizing film, in this order. Within the surface of the above laminated film, the above width direction and the above flow direction are perpendicular to each other.

Description

  The present invention relates to a method for producing a polarizing laminate film and a method for producing a polarizing plate.

  A polarizing plate is widely used as a polarized light supplying element and a polarized light detecting element in a liquid crystal display device. As such a polarizing plate, a polarizing film made of a polyvinyl alcohol resin and having a protective film made of triacetylcellulose bonded on one or both sides has been used. In recent years, notebook personal computers for liquid crystal display devices have been used. With the development of mobile devices such as mobile phones and mobile phones, as well as the development of large televisions, there is a demand for thinner and lighter polarizing plates.

  For example, in Patent Documents 1 to 4, as a method for producing a thin polarizing plate, a resin film made of a polyvinyl alcohol-based resin is formed on one surface of a base film to obtain a laminated film, and then such laminated film is used. Stretching and then dyeing the resin layer to form a polarizer layer to obtain a polarizing laminate film, which can be used as a polarizing plate as it is, or a protective film is bonded to the film, and then a base film There has been proposed a method of using a film obtained by peeling off the film as a polarizing plate.

JP 2000-338329 A JP 2009-93074 A JP 2009-98653 A JP 2003-43257 A

  However, in the method for producing a polarizing plate or the method for producing a polarizing laminated film as described above, if the laminated film is stretched at a high stretch ratio such as more than 5 times, the film is easily torn in the stretching direction, and tension is applied after stretching. When winding or unwinding, at the time of contact with the guide roll, or at the time of dyeing the resin layer, these actions may be a cause, and the laminated film may be severely broken in the stretching direction.

  Therefore, the present invention provides a polarizing laminated film or a polarizing plate production method in which a resin layer made of a polyvinyl alcohol resin is formed on a base film, and the laminated film is stretched in a uniaxial direction at a high draw ratio. Another object of the present invention is to provide a method for producing a polarizing laminated film and a method for producing a polarizing plate that can satisfactorily suppress the occurrence of tearing in the stretching direction in the subsequent steps.

  The present invention is a laminated film in which a base film is stretched in the width direction to obtain a stretched base film, and a resin layer made of a polyvinyl alcohol-based resin is formed on one surface of the stretched base film. A resin layer forming step, a second stretching step for uniaxially stretching the laminated film in the flow direction to obtain a stretched laminated film, and a polarizer layer by dyeing the resin layer of the stretched laminated film with a dichroic dye And a dyeing step of obtaining a polarizing film in this order, and a method for producing a polarizing laminated film, wherein the width direction and the flow direction are perpendicular to each other in the plane of the laminated film.

  The draw ratio in the second drawing step is preferably more than 5 times. The first stretching step is preferably a fixed end uniaxial stretching step, and the second stretching step is preferably a free end uniaxial stretching step. The base film is preferably made of a chain polyolefin resin.

  In the polarizer layer of the polarizing laminate film produced by the production method described above, the present invention provides a lamination step of obtaining a multilayer film by laminating a protective film on the surface opposite to the stretched substrate film side. The manufacturing method of a polarizing plate including the peeling process which peels the said base film from the said multilayer film in this order is provided.

  Moreover, this invention provides a liquid crystal display device provided with the polarizing plate manufactured by the said manufacturing method, and a liquid crystal cell.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method which can manufacture a thin polarizing plate or a polarizing laminated film, and can suppress the tear to the extending | stretching direction in a manufacture stage favorably is provided. Therefore, according to the present invention, a polarizing laminated film and a polarizing plate can be produced with good yield and stability.

  Moreover, according to the manufacturing method which concerns on this invention, since the thin polarizing laminated film and polarizing plate can be manufactured, the polarizing laminated film and polarizing plate suitable for the liquid crystal display device used for a mobile terminal etc. Can be manufactured.

It is a flowchart which shows the manufacturing method of the light-polarizing laminated film of this invention. It is a flowchart which shows the manufacturing method of the polarizing plate of this invention.

<Method for producing polarizing laminated film>
Hereinafter, with reference to drawings, preferred embodiment of the manufacturing method of the polarizing lamination film of the present invention is described in detail.

  FIG. 1 is a flowchart showing a method for producing a polarizing laminated film according to the present invention. The manufacturing method of the light-polarizing laminated film shown in FIG. 1 includes a first stretching step (S10) in which a base film is uniaxially stretched in the width direction (transverse direction) to obtain a stretched base film, and polyvinyl alcohol on the stretched base film. A resin layer forming step (S20) of forming a resin layer made of a resin and obtaining a laminated film, and the obtained laminated film is uniaxially stretched in the flow direction (longitudinal direction) which is the conveying direction of the laminated film to form a stretched laminated film A second stretching step (S30) to be obtained, and a dyeing step (S40) for obtaining a polarizing film by dyeing the resin layer with a dichroic dye to form a polarizer layer are provided in this order. The flow direction of the laminated film is perpendicular to the width direction of the stretched base film in the plane of the laminated film.

[First Stretching Step (S10)]
The first stretching step is a step of uniaxially stretching the base film in the width direction, and preferably performs fixed-end uniaxial stretching. The stretching method is not particularly limited, but a transverse stretching machine such as a tenter can be used. The stretching temperature is preferably performed in the vicinity of the phase transition temperature of the resin constituting the base film (a glass transition temperature Tg in the case of an amorphous resin and a melting point Tm in the case of a crystalline resin). It is preferable to stretch in the temperature range within ± 20 ° C. of the phase transition temperature of the resin constituting the base film. When the phase transition temperature exceeds + 20 ° C., the resin constituting the base film is in a molten state, making it difficult to stretch the base film, and when the phase transition temperature is lower than −20 ° C., the flow of the resin constituting the base film The base film is easy to break.

  The draw ratio in the first drawing step is preferably selected in a timely range of 1.5 to 6 times. As the draw ratio of the first stretching step (S10) is higher, the laminated film is less likely to break in the step after the second stretching step (S30), while the tensile strength in the flow direction of the base film may be reduced. Therefore, the selection may be made in a timely manner in consideration of the desired strength and the handling properties in the second stretching step (S30).

(Base film)
As a material for the base film used in the present invention, for example, a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, stretchability and the like is used. Specific examples of such thermoplastic resins include cellulose ester resins such as cellulose triacetate; polyester resins; polyethersulfone resins; polysulfone resins; polycarbonate resins; polyamide resins; And polyolefin resins such as cyclic resins and cyclic polyolefin resins (such as norbornene resins); (meth) acrylic resins; polyarylate resins; polystyrene resins; polyvinyl alcohol resins, and mixtures thereof. The material for the base film preferably includes at least one selected from the group consisting of cellulose ester resins, polyolefin resins, chain polyolefin resins, cyclic polyolefin resins, and (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, and cellulose dipropionate. Among these, cellulose triacetate is particularly preferable. Many products of cellulose triacetate are commercially available, which is advantageous in terms of availability and cost. Examples of commercially available cellulose triacetate are all trade names of “Fujitac (registered trademark) TD80” (manufactured by Fuji Film Co., Ltd.), “Fujitac (registered trademark) TD80UF” (manufactured by Fuji Film Co., Ltd.), “Fujitac (registered trademark) TD80UZ” (Fuji Film Co., Ltd.), “Fujitac (registered trademark) TD40UZ” (Fuji Film Co., Ltd.), “KC8UX2M” (Konica Minolta Opto Co., Ltd.), “KC4UY” (Konica Minolta Opto Co., Ltd.).

  Examples of the chain polyolefin-based resin include copolymers made of two or more chain olefins in addition to polymers such as polyethylene resins and polypropylene resins. When a base film made of polypropylene is used, it is preferable because it is easily stretched stably at a high magnification.

  Cyclic polyolefin resin is a general term for resins that are polymerized using cyclic olefin as a polymerization unit, and is described in, for example, JP-A-1-240517, JP-A-3-14882, JP-A-3-122137, and the like. Resin. Specific examples include cyclic olefin ring-opening (co) polymers, cyclic olefin addition polymers, cyclic olefins and chain olefins such as ethylene and propylene (typically random copolymers), And graft polymers obtained by modifying them with an unsaturated carboxylic acid or a derivative thereof, and hydrides thereof. Among these, norbornene resins using norbornene monomers such as norbornene and polycyclic norbornene monomers as cyclic olefins are preferably used.

  Various products are commercially available as cyclic polyolefin resins. Specific examples of commercial products of cyclic polyolefin resins are trade names, “Topas (registered trademark)” (manufactured by TOPAS ADVANCED POLYMERS GmbH, available from Polyplastics Co., Ltd.), “Arton (registered trademark) ) ”(Manufactured by JSR Corporation),“ ZEONOR (registered trademark) ”(manufactured by ZEON Corporation),“ ZEONEX (registered trademark) ”(manufactured by ZEON Corporation),“ Appel ” (Registered trademark) "(manufactured by Mitsui Chemicals, Inc.).

Any appropriate (meth) acrylic resin can be adopted as the (meth) acrylic resin. For example, poly (meth) acrylic acid ester such as polymethyl methacrylate, methyl methacrylate- (meth) acrylic acid copolymer, methyl methacrylate- (meth) acrylic acid ester copolymer, methyl methacrylate-acrylic acid ester -(Meth) acrylic acid copolymer, (meth) acrylic acid methyl-styrene copolymer (MS resin, etc.), polymer having an alicyclic hydrocarbon group (for example, methyl methacrylate-cyclohexyl methacrylate copolymer) And methyl methacrylate- (meth) acrylate norbornyl copolymer). Preferably, poly (meth) acrylic acid C _1-6 alkyl such as poly (meth) acrylate methyl is used. More preferably, as the (meth) acrylic resin, a methyl methacrylate-based resin containing methyl methacrylate as a main component (50 to 100% by weight, preferably 70 to 100% by weight) is used.

  Among the thermoplastic resins described above, the base film is preferably made of a chain polyolefin-based resin because it is excellent in stretchability and easy to adjust the phase transition temperature. A polypropylene resin that is a polymer, a copolymer mainly composed of propylene), a polyethylene resin (a polyethylene resin that is a homopolymer of ethylene, a copolymer mainly composed of ethylene, and the like). preferable.

  The chain polyolefin resin is often crystalline, and the polypropylene resin, which is a propylene homopolymer, has a melting point Tm in the range of about 150 to 180 ° C. In the case of a polyethylene resin which is a homopolymer of ethylene, the melting point Tm can vary depending on its density and the like, but the melting point Tm is generally in the range of 100 to 140 ° C. Further, for example, according to a polypropylene resin obtained by copolymerizing propylene with another monomer such as ethylene, a melting point lower than the melting point of a propylene homopolymer can be obtained. Thus, the phase transition temperature of the resin can be controlled by adjusting the type of the main monomer, the presence or absence of the copolymer component, or the type and content of the copolymer component.

  Examples of other types of monomers copolymerizable with propylene include ethylene and α-olefin. As the α-olefin, an α-olefin having 4 or more carbon atoms is preferably used, and more preferably an α-olefin having 4 to 10 carbon atoms. Specific examples of the α-olefin having 4 to 10 carbon atoms include linear 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, 4-methyl-1-pentene; vinylcyclohexane and the like. The copolymer of propylene and other monomers copolymerizable therewith may be a random copolymer or a block copolymer. In addition, the content rate of the structural unit derived from the said other monomer in a copolymer is infrared (IR) according to the method described on page 616 of "Polymer Analysis Handbook" (1995, published by Kinokuniya) ) It can be obtained by performing a spectrum measurement.

  Among these, as the propylene-based resin, a propylene homopolymer, a propylene-ethylene random copolymer, a propylene-1-butene random copolymer, and a propylene-ethylene-1-butene random copolymer are preferable. Used.

  The stereoregularity of the propylene-based resin is preferably substantially isotactic or syndiotactic. The base film including a resin layer made of a propylene-based resin having substantially isotactic or syndiotactic stereoregularity has relatively good handling properties and excellent mechanical strength in a high temperature environment. ing.

  Arbitrary appropriate additives other than said thermoplastic resin may be added to the base film. Examples of such additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, and coloring agents. . The content of the thermoplastic resin exemplified above in the base film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, and particularly preferably 70 to 97%. % By weight. This is because, if the content of the thermoplastic resin in the base film is less than 50% by weight, the high transparency inherent in the thermoplastic resin may not be sufficiently exhibited.

  Although the thickness of the base film before the first stretching step can be determined as appropriate, it is generally preferably 1 to 500 μm, more preferably 1 to 300 μm, and even more preferably 5 from the viewpoint of workability such as strength and handleability. ˜200 μm is preferred. As for the thickness of a base film, 5-150 micrometers is the most preferable.

  The base film may be subjected to corona treatment, plasma treatment, flame treatment or the like on at least the surface on which the resin layer is formed in order to improve the adhesion with the resin layer. Moreover, in order to improve adhesiveness, you may form thin layers, such as a primer layer, in the surface at the side by which the resin layer of a base film is formed.

[Resin layer forming step (S20)]
In the resin layer forming step (S20) shown in FIG. 1, a resin layer made of a polyvinyl alcohol-based resin is formed on one surface of the base film. Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol resins and derivatives thereof. Derivatives of polyvinyl alcohol resin include polyvinyl formal, polyvinyl acetal, etc., olefins such as ethylene and propylene, unsaturated carboxylic acids such as acrylic acid, methacrylic acid and crotonic acid, and alkyl esters of unsaturated carboxylic acids. And those modified with acrylamide or the like. Among the above-mentioned polyvinyl alcohol-based resin materials, it is preferable to use a polyvinyl alcohol resin.

  100-10000 are preferable and, as for the average degree of polymerization of polyvinyl alcohol-type resin, 1000-10000 are more preferable. If the average degree of polymerization is less than 100, it may be difficult to obtain preferable optical characteristics. When the average degree of polymerization is more than 10,000, the solubility in water is deteriorated and it may be difficult to form a resin layer. The average saponification degree of the polyvinyl alcohol resin is preferably 80 to 100 mol%, more preferably 98 mol% or more. If the average saponification degree is less than 80 mol%, it may be difficult to obtain preferable optical characteristics.

  In the above-mentioned polyvinyl alcohol resin, additives such as a plasticizer and a surfactant may be added as necessary. As the plasticizer, polyols and condensates 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 not particularly limited, but is preferably 20% by weight or less in the polyvinyl alcohol resin.

  The thickness of the resin layer is preferably more than 3 μm and not more than 30 μm, and more preferably 5 to 20 μm. If it is 3 μm or less, the film becomes too thin after stretching in the second stretching step and the dyeability is remarkably deteriorated. If it exceeds 30 μm, the thickness of the polarizing plate increases, which is not preferable.

  The resin layer in the present invention is preferably formed by coating a polyvinyl alcohol resin solution obtained by dissolving polyvinyl alcohol resin powder in a good solvent on one surface of the substrate film and evaporating the solvent. It is formed. By forming the resin layer in this way, it can be formed thin. As a method for coating a polyvinyl alcohol resin solution on a base film, a wire bar coating method, a roll coating method such as reverse coating or gravure coating, a spin coating method, a screen coating method, a fountain coating method, a dipping method, or a spray method. Etc. can be appropriately selected from known methods. A drying temperature is 50-200 degreeC, for example, Preferably it is 60-150 degreeC. The drying time is, for example, 5 to 30 minutes.

  In addition, the resin layer in this invention can also be formed by sticking the raw film which consists of polyvinyl alcohol-type resins on one surface of a base film.

[Second stretching step (S30)]
In the 2nd extending | stretching process (S30) shown in FIG. 1, the laminated | multilayer film which consists of a base film and a resin layer are uniaxially stretched in a flow direction, and a stretched laminated film is obtained. Here, the original length of the laminated film is preferably uniaxially stretched so that the stretch ratio is more than 5 times. More preferably, the film is uniaxially stretched so that the draw ratio is more than 5 times and not more than 17 times. Most preferably, it is uniaxially stretched so that the draw ratio is more than 5 times and not more than 8 times. When the draw ratio is 5 times or less, the resin layer made of the polyvinyl alcohol-based resin is not sufficiently oriented, and as a result, the polarization degree of the polarizing film is not sufficiently increased. On the other hand, if the draw ratio exceeds 17 times, the laminated film is liable to break during stretching, and at the same time, the thickness of the laminated film becomes unnecessarily thin, and the workability and handling properties in the subsequent steps may be reduced.

  The stretching process in the second stretching process (S30) is not limited to stretching in one stage, and can be performed in multiple stages. In the case of performing in multiple stages, it is preferable to perform the stretching process so as to obtain a stretching ratio exceeding 5 times in total for all stages of the stretching process.

  In the 2nd extending process (S30) in this invention, a uniaxial stretching process is performed with respect to the flow direction which is a conveyance direction of a laminated | multilayer film. The uniaxial stretching in the second stretching step is preferably free end uniaxial stretching. Examples of the free end uniaxial stretching method include an inter-roll stretching method and a compression stretching method.

  In stretching, either a wet stretching method or a dry stretching method can be employed. However, the dry stretching method is preferable because the temperature at which the laminated film is stretched can be selected from a wide range.

[Dyeing process (S40)]
In the dyeing step (S40) shown in FIG. 1, the resin layer of the stretched laminated film is dyed with a dichroic material to obtain a dyed film. Examples of the dichroic substance include iodine and organic dyes. Examples of organic dyes include Red BR, Red LR, Red R, Pink LB, Rubin BL, Bordeaux GS, Sky Blue LG, Lemon Yellow, Blue BR, Blue 2R, Navy RY, Green LG, Violet LB, Violet B, Black H, Black B, Black GSP, Yellow 3G, Yellow R, Orange LR, Orange 3R, Scarlet GL, Scarlet KGL, Congo Red, Brilliant Violet BK, Spura Blue G, Spura Blue GL, Spura Orange GL, Direct Sky Blue, Direct First Orange S, First Black, etc. can be used. One kind of these dichroic substances may be used, or two or more kinds may be used in combination.

  A dyeing process is performed by immersing the whole extending | stretching laminated | multilayer film which consists of a base film and a resin layer in the solution (dyeing solution) containing the said dichroic substance, for example. As the staining solution, a solution in which the above dichroic substance is dissolved in a solvent can be used. As a solvent for the dyeing solution, water is generally used, but an organic solvent compatible with water may be further added. The concentration of the dichroic substance is preferably 0.01 to 10% by weight, more preferably 0.02 to 7% by weight, and particularly preferably 0.025 to 5% by weight.

  When iodine is used as the dichroic substance, it is preferable to further add iodide to the dyeing solution containing iodine because 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 iodide. Examples include titanium. The addition ratio of these iodides is preferably 0.01 to 10% by weight in the dyeing solution. Of the 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 by weight. , Particularly preferably in the range of 1: 7 to 1:70.

  The immersion time of the stretched laminated film in the dyeing solution is not particularly limited, but it is usually preferably in the range of 15 seconds to 15 minutes, more preferably 1 minute to 3 minutes. Moreover, it is preferable that it is in the range of 10-60 degreeC, and, as for the temperature of a dyeing | staining solution, it is more preferable that it exists in the range of 20-40 degreeC.

[Other processes]
A crosslinking process can be performed after the dyeing process (S40) shown in FIG. The crosslinking step can be performed, for example, by immersing the dyed film in a solution containing a crosslinking agent (crosslinking solution). Conventionally known substances can be used as the crosslinking agent. Examples thereof include boron compounds such as boric acid and borax, glyoxal, and glutaraldehyde. One kind of these may be used, or two or more kinds may be used in combination.

  As the crosslinking solution, a solution in which a crosslinking agent is dissolved in a solvent can be used. As the solvent, for example, water can be used, but an organic solvent compatible with water may be further included. Although the density | concentration of the crosslinking agent in a crosslinking solution is not limited to this, It is preferable to exist in the range of 1 to 10 weight%, and it is more preferable that it is 2 to 6 weight%.

  Iodide may be added to the crosslinking solution. By adding iodide, the in-plane polarization characteristics of the resin layer 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. Is mentioned. The iodide content is 0.05 to 15% by weight, more preferably 0.5 to 8% by weight.

  The immersion time of the stretched laminated film in the crosslinking solution is usually preferably from 15 seconds to 20 minutes, and more preferably from 30 seconds to 15 minutes. Moreover, it is preferable that the temperature of a crosslinking solution exists in the range of 10-80 degreeC.

  In the cross-linking step, the cross-linking step and the dyeing step (S40) can be simultaneously performed by blending a cross-linking agent into the dyeing solution.

  After the dyeing step (S40) and the crosslinking step are completed, it is preferable to finally perform a washing step and a drying step. As the washing step, a water washing treatment can be performed. A water washing process can be normally performed by immersing the stretched laminated film which passed through the dyeing process (S40) and the bridge | crosslinking process in pure water, such as ion-exchange water and distilled water. The water washing temperature is usually in the range of 3 to 50 ° C, preferably 4 to 20 ° C. The immersion time is usually 2 to 300 seconds, preferably 5 to 240 seconds.

  In the washing step, washing treatment with an iodide solution and water washing treatment may be combined, and a solution in which liquid alcohol such as methanol, ethanol, isopropyl alcohol, butanol, propanol or the like is appropriately blended may be used.

  It is preferable to perform a drying process after the washing process. Any appropriate method (for example, natural drying, ventilation drying, heat drying) can be adopted as the drying step. For example, the drying temperature in the case of heat drying is usually 20 to 95 ° C., and the drying time is usually about 1 to 15 minutes. Through the above treatment, the resin layer has a function as a polarizer layer, and a polarizing film is obtained.

  The polarizing laminate film produced through the above steps can be used as a polarizing plate as it is, or can be used for the polarizing plate production step shown in FIG.

<Production method of polarizing plate>
Hereinafter, a preferred embodiment of a method for producing a polarizing plate of the present invention will be described in detail with reference to the drawings.

  FIG. 2 is a flowchart showing a method for manufacturing a polarizing plate according to the present invention. As in the manufacturing method of the polarizing laminated film shown in FIG. 1, first, through the first stretching step (S10), the resin layer forming step (S20), the second stretching step (S30), and the dyeing step (S40), A polarizing laminated film is produced. Thereafter, in the polarizer layer of the polarizing laminated film, a bonding step (S50) for obtaining a multilayer film by pasting a protective film on the surface opposite to the stretched substrate film side, and a stretched substrate film from the multilayer film And a peeling step (S60) for peeling are performed in this order. The manufacturing method for manufacturing the polarizing laminated film through the steps S10 to S40 is the same as the content described above with reference to FIG. 1 and therefore will not be described. Hereinafter, for each step of S50 and S60, This will be described in detail.

[Bonding process (S50)]
In the bonding process (S50) shown in FIG. 2, a protective film is bonded to the surface on the opposite side of the stretched base film side of the polarizing laminated film to obtain a multilayer film. As a method of bonding a protective film, the method of bonding a polarizing laminated film and a protective film with an adhesive, and the method of bonding a polarizing laminated film and a protective film with an adhesive are mentioned.

(Protective film)
The protective film used in the present invention comprises a polyolefin resin such as a chain polyolefin resin (polypropylene resin, etc.), a cyclic polyolefin resin (norbornene resin, etc.); a resin such as cellulose triacetate or cellulose diacetate. Cellulose ester-based resin films; films that have been widely used in this field, such as polyester-based resin films, polycarbonate-based resin films, and acrylic-based resin films made of resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate Can be mentioned.

  As the cyclic polyolefin-based resin, appropriate commercial products such as “Topas (registered trademark)” (manufactured by TOPAS ADVANCED POLYMERS GmbH, available from Polyplastics Co., Ltd.), “Arton” (registered) Trademark) "(manufactured by JSR Corporation)," ZEONOR "(registered trademark) (manufactured by ZEON Corporation)," ZEONEX (registered trademark) (ZEONEX) "(manufactured by ZEON Corporation)," “Apel (registered trademark)” (manufactured by Mitsui Chemicals, Inc.) can be suitably used. When such a cyclic polyolefin resin is formed into a film, a known method such as a solvent casting method or a melt extrusion method is appropriately used. In addition, “Essina (registered trademark)” (manufactured by Sekisui Chemical Co., Ltd.), “SCA40” (manufactured by Sekisui Chemical Co., Ltd.), “Zeonor (registered trademark) film” (manufactured by Nippon Zeon Co., Ltd.), etc. A commercial product of a film made of a cyclic polyolefin resin formed in advance may be used.

  The cyclic polyolefin resin film may be uniaxially stretched or biaxially stretched. An arbitrary retardation value can be imparted to the cyclic polyolefin-based resin film by stretching. Stretching is usually performed continuously while unwinding the film roll, and is stretched in a heating furnace in a roll flow direction, a direction perpendicular to the flow direction, or both. The temperature of the heating furnace is usually in the range from near the phase transition temperature of the cyclic polyolefin resin to the phase transition temperature + 100 ° C. The draw ratio is usually 1.1 to 6 times, preferably 1.1 to 3.5 times in one direction.

  Since the cyclic polyolefin resin film is generally inferior in surface activity, surface treatment such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame (flame) treatment, saponification treatment is performed on the surface to be bonded to the polarizing laminated film. Is preferred. Among these, plasma treatment and corona treatment that can be performed relatively easily are preferable.

  As the cellulose ester-based resin film, appropriate commercial products such as “Fujitac (registered trademark) TD80” (manufactured by Fuji Film Co., Ltd.), “Fujitac (registered trademark) TD80UF” (Fuji Film ( Co., Ltd.), “Fujitac (registered trademark) TD80UZ” (Fuji Film Co., Ltd.), “Fujitac (registered trademark) TD40UZ” (Fuji Film Co., Ltd.), “KC8UX2M” (Konica Minolta Opto Co., Ltd.) ), “KC4UY” (manufactured by Konica Minolta Opto Co., Ltd.) can be suitably used.

  A liquid crystal layer or the like may be formed on the surface of the cellulose ester resin film in order to improve viewing angle characteristics. Moreover, what extended | stretched the cellulose-ester-type resin film in order to provide a phase difference may be used. The cellulose ester resin film is usually subjected to a saponification treatment in order to enhance the adhesiveness with the polarizing laminated film. As the saponification treatment, a method of immersing in an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide can be employed.

  When the protective film as described above is in a roll state, the films tend to adhere to each other and easily cause blocking. Therefore, preferably, the roll end is subjected to uneven processing, or a ribbon is inserted into the end. A protective film is pasted and rolled.

  The thickness of the protective film is preferably thin, but if it is too thin, the strength is lowered and the processability is poor. On the other hand, when it is too thick, problems such as a decrease in transparency and a longer curing time after lamination occur. Therefore, the thickness of the protective film is preferably 80 μm or less, and more preferably 5 to 60 μm. Further, since there is a demand for thinning including panels and modules from the market, the polarizing plate and the protective film may have a total thickness of 100 μm or less because the polarizing plate is also required to be thin. More preferably, it is 90 micrometers or less, More preferably, it is 80 micrometers or less.

  In addition, an optical layer such as a hard coat layer, an antiglare layer, or an antireflection layer can be directly formed on the surface of the protective film. The method for forming these optical layers on the surface of the protective film is not particularly limited, and a known method can be used.

(Adhesive)
The pressure-sensitive adhesive used for laminating the protective film and the polarizing laminated film is usually based on an acrylic resin, styrene resin, silicone resin or the like, and there are isocyanate compounds, epoxy compounds, aziridine compounds, etc. It consists of a composition to which a crosslinking agent is added. Furthermore, it can also be set as the adhesive layer which contains microparticles | fine-particles and shows light-scattering property.

  The thickness of the pressure-sensitive adhesive layer is preferably 1 to 40 μm, but it is preferably applied thinly, and more preferably 3 to 25 μm, as long as the workability and durability characteristics are not impaired. When it is 3 to 25 μm, it has good processability and is also suitable for suppressing the dimensional change of the polarizing film. When the pressure-sensitive adhesive layer is less than 1 μm, the tackiness is lowered, and when it exceeds 40 μm, problems such as the pressure-sensitive adhesive protruding easily occur.

  In the method of bonding the protective film to the polarizing laminated film with an adhesive, after the adhesive layer is provided on the protective film surface, the protective film may be bonded to the polarizing laminated film surface or adhered to the polarizing laminated film surface. After providing the agent layer, a protective film may be bonded here.

  The method for forming the pressure-sensitive adhesive layer is not particularly limited, and a solution containing each component including the above-mentioned base polymer is applied to the protective film surface or the polarizing laminated film surface, and dried to be a pressure-sensitive adhesive. After forming the layer, the protective film and the polarizing laminated film may be bonded together, or after forming the pressure-sensitive adhesive layer on the separator, it may be transferred and laminated on the protective film surface or the polarizing laminated film surface. Good. Further, when forming the pressure-sensitive adhesive layer on the protective film or the polarizing laminated film surface, if necessary, the protective film or the polarizing laminated film surface, or one or both of the pressure-sensitive adhesives are subjected to an adhesion treatment such as corona treatment. You may give it.

(adhesive)
Examples of the adhesive used for bonding the protective film and the polarizing laminated film include a water-based adhesive using a polyvinyl alcohol-based resin aqueous solution, a water-based two-component urethane-based emulsion adhesive, and the like. When using the cellulose ester-type resin film hydrophilized by the saponification process etc. as a protective film, polyvinyl alcohol-type resin aqueous solution is used suitably as a water-based adhesive for bonding with a polarizing laminated film. Polyvinyl alcohol resins used as adhesives include vinyl alcohol homopolymers obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, as well as other single quantities copolymerizable with vinyl acetate. And vinyl alcohol copolymers obtained by saponifying the copolymer with the polymer, and modified polyvinyl alcohol polymers obtained by partially modifying the hydroxyl groups. A polyhydric aldehyde, a water-soluble epoxy compound, a melamine compound, a zirconia compound, a zinc compound, or the like may be added as an additive to the water-based adhesive. When such an aqueous adhesive is used, the adhesive layer obtained therefrom is usually 1 μm or less, and even when the cross section is observed with a normal optical microscope, the adhesive layer is practically not observed.

  The method of laminating the polarizing laminate film and the protective film using the water-based adhesive is not particularly limited. For example, casting method, Meyer bar coating method, gravure coating method, comma coater method, doctor plate method The adhesive is uniformly applied to the surface of the polarizing laminated film and / or the protective film by the die coating method, the dip coating method, the spraying method, etc. The method of drying etc. are mentioned. The casting method is a method for spreading a polarizing laminated film or a protective film, which is an object to be coated, by moving an adhesive on the surface while moving it in a substantially vertical direction, a substantially horizontal direction, or an oblique direction between them. It is a method to make it. Usually, an adhesive agent is apply | coated at the temperature of 15-40 degreeC after the preparation, and the bonding temperature is the range of 15-30 degreeC normally.

  When using a water-based adhesive, after laminating the polarizing laminate film and the protective film, the multilayer film is dried to remove water contained in the water-based adhesive. The temperature of the drying furnace is preferably 30 ° C to 90 ° C. When the temperature is lower than 30 ° C., the polarizing laminated film surface and the protective film surface tend to be easily peeled off. If it is 90 ° C. or higher, the optical 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 drying, it may be further cured for about 12 to 600 hours at room temperature or a slightly higher temperature, for example, a temperature of about 20 to 45 ° C. The temperature at the time of curing is generally set lower than the temperature adopted at the time of drying.

  After the adhesive is applied to the surface of the polarizing laminated film or the protective film, the polarizing laminated film and the protective film are bonded together by being sandwiched by a nip roll or the like through the adhesive application surface. There is also a method in which an adhesive is dropped between the polarizing laminated film and the protective film in a state where the polarizing laminated film and the protective film are overlapped, and then the multilayer film is pressed with a roll or the like to spread it uniformly. It can be preferably used. In this case, a metal, rubber, or the like can be used as the material of the roll. Furthermore, after dropping an adhesive agent between a light-polarizing laminated film and a protective film, a method of passing this multilayer film between rolls and pressurizing and spreading it is also preferably employed. In this case, these rolls may be made of the same material or different materials. The thickness of the adhesive layer after being bonded using the nip roll or the like before drying or curing is preferably 5 μm or less and 0.01 μm or more.

  The adhesive surface of the polarizing laminate film and / or protective film is appropriately subjected to surface treatment such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame (flame) treatment, saponification treatment, etc. in order to improve adhesion. Also good. Examples of the saponification treatment include a method of immersing in an aqueous alkali solution such as sodium hydroxide or potassium hydroxide.

  Moreover, a photocurable adhesive can also be used as an adhesive at the time of bonding a polarizing laminated film and a protective film. Examples of the photocurable adhesive include a mixture of a photocurable epoxy resin and a photocationic polymerization initiator.

  When a photocurable resin is used as an adhesive, the photocurable adhesive is cured by irradiating active energy rays after joining the polarizing laminate film and the protective film. 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, the low-pressure mercury lamp, the medium-pressure mercury lamp, the high-pressure mercury lamp, the ultrahigh-pressure mercury lamp, the chemical lamp, and the black light lamp A microwave excitation mercury lamp, a metal halide lamp and the like are preferably used.

The light irradiation intensity to the photocurable adhesive is appropriately determined depending on the composition of the photocurable adhesive and is not particularly limited, but the irradiation intensity in the wavelength region effective for activating the polymerization initiator is 0.1 to 6000 mW / it is preferable that the cm ^2. When the irradiation intensity is 0.1 mW / cm ² or more, the reaction time does not become too long, and when it is 6000 mW / cm ² or less, the epoxy is generated by the heat radiated from the light source and the heat generated when the photo-curable adhesive is cured. There is little possibility of causing yellowing of the resin and deterioration of the polarizing laminated film. The light irradiation time to the photocurable adhesive is not particularly limited and is applied according to the photocurable adhesive to be cured, but the integrated light amount expressed as the product of the irradiation intensity and the irradiation time. Is preferably set to be 10 to 10,000 mJ / cm ² . When the cumulative amount of light to the photocurable adhesive is 10 mJ / cm ² or more, a sufficient amount of active species derived from the polymerization initiator can be generated to allow the curing reaction to proceed more reliably, and at 10,000 mJ / cm ² or less. In some cases, irradiation time does not become too long and good productivity can be maintained. The thickness of the adhesive layer after irradiation with active energy rays is usually about 0.001 to 5 μm, preferably 0.01 μm or more and 2 μm or less, more preferably 0.01 μm or more and 1 μm or less.

  When curing a photocurable adhesive by irradiation with active energy rays, curing is performed under conditions that do not deteriorate the functions of the polarizing plate, such as the degree of polarization of the polarizing laminate film, the transmittance and hue, and the transparency of the protective film. It is preferable.

[Peeling step (S60)]
In the manufacturing method of the polarizing plate of this invention, as shown in FIG. 2, the extending | stretching base film is made from a multilayer film after the bonding process (S50) which bonds a protective film to a polarizing laminated film, and obtains a multilayer film. The peeling process (S60) which peels is performed. The peeling method of a extending | stretching base film is not specifically limited, It can peel by the method similar to the peeling process of the peeling film performed with a normal polarizing plate with an adhesive. After the pasting step (S50), it may be peeled off as it is, or after the protective film pasting step (S50), once wound up in a roll, and then unwinding in the subsequent step, the peeling step (S60). May be performed.

[Other processes]
The polarizing plate produced through the above steps may be used as it is as a polarizing plate for a liquid crystal display device, or may be used as an optical film through a step of further laminating another optical layer in practical use. Moreover, the said protective film may have a function of these optical layers. Examples of other optical layers include a reflective polarizing film that transmits certain types of polarized light and reflects polarized light that exhibits the opposite properties, a film with an antiglare function having an uneven shape on the surface, and a surface antireflection function. Examples thereof include an attached film, a reflective film having a reflective function on the surface, a transflective film having both a reflective function and a transmissive function, and a viewing angle compensation film.

  As a commercial product corresponding to a reflective polarizing film that transmits a certain kind of polarized light and reflects polarized light having the opposite property, for example, “DBEF” (manufactured by 3M, Sumitomo 3M Co., Ltd.) ), “APF” (manufactured by 3M, available from Sumitomo 3M Limited). Examples of the viewing angle compensation film include an optical compensation film coated with a liquid crystal compound on the surface of the substrate and oriented, a retardation film made of a polycarbonate resin, and a retardation film made of a cyclic polyolefin resin. Commercially available products corresponding to an optical compensation film in which a liquid crystal compound is coated on the substrate surface and oriented are “WV film” (Fuji Film Co., Ltd.) and “NH film” (New Japan). Petroleum Co., Ltd.), “NR Film” (manufactured by Nippon Oil Corporation), and the like. In addition, commercially available products corresponding to retardation films made of cyclic polyolefin-based resins include “Arton (registered trademark) film” (manufactured by JSR Corporation), “Essina (registered trademark)” (manufactured by Sekisui Chemical Co., Ltd.). ), “ZEONOR (registered trademark) film” (manufactured by Nippon Zeon Co., Ltd.), and the like.

  According to the above manufacturing method, a thin polarizing laminated film and polarizing plate can be manufactured, so it is useful for mobile terminals that require thinness, and in addition, exhibits excellent polarization performance and is mounted on a display device. There is an advantage that a high contrast ratio can be obtained.

<Liquid crystal display device>
A polarizing laminate sheet manufactured by the manufacturing method shown in FIG. 1 or a liquid crystal display device including a polarizing plate manufactured by the manufacturing method shown in FIG. 2 can be configured. The liquid crystal display device can be manufactured according to a conventionally known method. That is, the liquid crystal display device is generally formed by appropriately assembling a liquid crystal cell, a polarizing plate, and other components such as a lighting system as necessary, and further incorporating a drive circuit. The liquid crystal display device according to the present invention is not particularly limited except that the polarizing plate manufactured by the manufacturing method according to the present invention is used, and is similar to the conventional one. As the liquid crystal cell, any type such as a TN type or an STN type can be used.

  A liquid crystal display device can be configured by disposing a polarizing plate on one side or both sides of a liquid crystal cell and further using a backlight or a reflection plate as appropriate in an illumination system. In such a liquid crystal display device, at least one of the polarizing plates disposed on one side or both sides of the liquid crystal cell is a polarizing plate manufactured by the manufacturing method according to the present invention. When providing polarizing plates on both sides, they may be the same or different. In addition to the above, the liquid crystal display device can be configured by combining appropriate elements such as a diffusion plate, an antireflection film, a protective plate, a prism array, and a lens array sheet.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated further more concretely, this invention is not limited by these examples.

[Example 1]
(Base film)
An unstretched polypropylene (PP) film (melting point: 163 ° C.) having a thickness of 110 μm was formed into a base film by an extruder.

(First stretching step)
Using a tenter, the base film was uniaxially stretched in the width direction at a stretch ratio of 2 times at a temperature of 160 ° C. to obtain a stretched base film.

(Primer layer formation process)
Polyvinyl alcohol powder (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., average polymerization degree 1100, average saponification degree 99.5 mol%, trade name: Z-200) was dissolved in 95 ° C. hot water, and the concentration was 3% by weight. An aqueous solution was prepared. The resulting aqueous solution was mixed with 5 parts by weight of a crosslinking agent (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumirez (registered trademark) resin 650) with respect to 6 parts by weight of polyvinyl alcohol powder. The obtained mixed aqueous solution was coated on a stretched substrate film subjected to corona treatment using a micro gravure coater and dried at 80 ° C. for 10 minutes to form a primer layer having a thickness of 0.2 μm.

(Resin layer forming process)
Using polyvinyl alcohol powder, PVA124 (manufactured by Kuraray Co., Ltd., average polymerization degree 2400, average saponification degree 98.0-99.0 mol%) was dissolved in hot water at 95 ° C. and the concentration was 8% by weight. An aqueous polyvinyl alcohol solution was prepared. The obtained aqueous solution was coated on the primer layer using a lip coater, and continuously dried at 80 ° C. for 2 minutes, 70 ° C. for 2 minutes, and 60 ° C. for 4 minutes, and stretched base film, primer layer A three-layer laminated film composed of a resin layer was prepared.

(Second stretching step)
The laminated film was uniaxially stretched in the flow direction at a stretching temperature of 160 ° C. at a stretching ratio of 5.8 times to obtain a stretched laminated film. The obtained stretched laminated film had a thickness of 28.5 μm.

(Measurement of tear strength)
The tear strength of the stretched laminated film obtained in Example 1 was measured by the following method. First, an incision was made in the stretching direction in the second stretching step from the center of the short side edge of the stretched laminated film (the center in the width direction of the film) using a cutter. Next, using a universal tensile testing machine (manufactured by Shimadzu Corporation, Autograph AG-I), the stretched laminated film was torn from the base point of the cut, and the tear strength at that time was measured using the same apparatus. The speed at which the stretched laminated film was torn was set to 300 mm / min. This measurement gives the tear strength at each tear distance (distance of the film torn from the base point of the cut), but in the tear strength measurement using a tensile tester, it reaches a certain tear distance and tears the film. Until the angle stabilizes, the tear strength often increases. Therefore, in this measurement, except for the portion where the strength is high, an average value of the tear strength in a region where the tear strength is stable was obtained and used as the tear strength. The tear strength of the stretched laminated film of Example 1 was 0.065 N, which showed good characteristics that were not easily torn. The results are shown in Table 1.

(Dyeing process)
Thereafter, the stretched laminated film is dipped in a 60 ° C. warm bath for 60 seconds, dyed by dipping in a dyeing solution that is a mixed aqueous solution of iodine and potassium iodide at 30 ° C. for about 150 seconds, and then excess with 10 ° C. pure water. The iodine solution was washed away. Next, it was immersed in a mixed aqueous solution of boric acid and potassium iodide at 76 ° C. for 600 seconds. Thereafter, the film was washed with pure water at 10 ° C. for 4 seconds, and finally dried at 50 ° C. for 300 seconds to obtain a polarizing laminated film. The laminated film was not torn in the dyeing process, and the polarizing laminated film could be produced stably. The results are shown in Table 1.

[Example 2]
Example except that an unstretched polypropylene (PP) film (melting point: 163 ° C.) having a thickness of 240 μm was used as a base film, and a stretched base film was obtained by uniaxially stretching in the width direction at a stretch ratio of 4 times. A stretched laminated film was obtained in the same manner as in 1.

  The stretched laminated film had a film thickness of 29.8 μm and a tear strength of 0.081 N, and exhibited very good characteristics that were not easily torn. The results are shown in Table 1.

  Then, in the stretched laminated film according to this example, the same treatment as in Example 1 including the dyeing process was performed to produce a polarizing laminated film. In the dyeing process, the laminated film was not torn, and the polarizing laminated film could be produced stably. The results are shown in Table 1.

[Example 3]
Example except that an unstretched polypropylene (PP) film (melting point: 163 ° C.) having a thickness of 300 μm was used as a base film, and a stretched base film was obtained by uniaxially stretching in the width direction at a stretch ratio of 5 times. A stretched laminated film was obtained in the same manner as in 1.

  The stretched laminated film had a film thickness of 30.4 μm and a tear strength of 0.102 N, which showed very good characteristics that were not easily torn. The results are shown in Table 1.

  Then, in the stretched laminated film according to this example, the same treatment as in Example 1 including the dyeing process was performed to produce a polarizing laminated film. In the dyeing process, the laminated film was not torn, and the polarizing laminated film could be produced stably. The results are shown in Table 1.

[Comparative Example 1]
An unstretched polypropylene (PP) film (melting point: 163 ° C.) having a thickness of 110 μm was used as a base film. A stretched laminated film was obtained in the same manner as in Example 1 except that this substrate film was not subjected to fixed-end uniaxial stretching.

  The stretched laminated film had a film thickness of 34.0 μm and a tear strength of 0.041 N, and was easily torn in the longitudinal direction. After that, it was difficult to carry out the dyeing process stably. The results are shown in Table 1.

[Example 4]
Using the polarizing laminate film obtained in Example 3, a polarizing plate was prepared by the following method.

(Bonding process)
A polyvinyl alcohol powder (manufactured by Kuraray Co., Ltd., average polymerization degree 1800, trade name: KL-318) was dissolved in hot water at 95 ° C. to prepare an aqueous solution having a concentration of 3% by weight. The resulting aqueous solution was mixed with 1 part by weight of a crosslinking agent (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumirez (registered trademark) Resin 650) with respect to 2 parts by weight of polyvinyl alcohol powder to obtain an adhesive solution. A protective film (manufactured by Konica Minolta Opto Co., Ltd.) was applied after applying the above-mentioned polyvinyl alcohol-based adhesive on the surface of the polarizer layer of the polarizing laminate film obtained in Example 3 opposite to the surface on the base film side. TAC: KC4UY) was bonded to obtain a polarizing plate comprising five layers of a protective film, an adhesive layer, a polarizer layer, a primer layer, and a stretched substrate film.

(Peeling process)
The stretched substrate film was peeled from the obtained polarizing plate. The stretched substrate film was easily peeled off to obtain a polarizing plate comprising four layers of a protective film, an adhesive layer, a polarizer layer, and a primer layer.

Claims (6)

A first stretching step of stretching the base film in the width direction to obtain a stretched base film;
A resin layer forming step of obtaining a laminated film by forming a resin layer made of a polyvinyl alcohol-based resin on one surface of the stretched substrate film;
A second stretching step to obtain a stretched laminated film by uniaxially stretching the laminated film in the flow direction;
Dyeing the resin layer of the stretched laminated film with a dichroic dye to form a polarizer layer, and obtaining a polarizing film, in this order,
In the plane of the laminated film, the width direction and the flow direction are vertical.
Manufacturing method of polarizing laminated film.   The manufacturing method of the light-polarizing laminated film of Claim 1 whose draw ratio in a 2nd extending process is 5 times or more.   The method for producing a polarizing laminated film according to claim 1 or 2, wherein the first stretching step is a fixed-end uniaxial stretching step, and the second stretching step is a free-end uniaxial stretching step.   The manufacturing method of the polarizing laminated film in any one of Claims 1-3 in which the said base film consists of chain | strand-shaped polyolefin resin. In the said polarizer layer of the polarizing laminated film manufactured by the method in any one of Claims 1-4, a protective film is bonded on the surface on the opposite side to the said extending | stretching base film side, and a multilayer film is obtained. A bonding process;
A peeling step of peeling the stretched substrate film from the multilayer film;
In this order.   A liquid crystal display device comprising a polarizing plate produced by the production method according to claim 5 and a liquid crystal cell.

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