JP2013015755A - Production method of polarizing laminate film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of a polarizing laminate film, in which tearing in an orientation direction in a dyeing process can be well suppressed.SOLUTION: The production method of a polarizing laminate film includes steps of: obtaining a laminate film by forming a polyvinyl alcohol resin layer on one surface of a substrate film comprising a thermoplastic resin and a rubber component dispersed in the resin; obtaining an oriented film by uniaxially orienting the laminate film; obtaining a dyed film by dyeing the polyvinyl alcohol resin layer of the oriented film with a dichroic dye; obtaining a crosslinked film by immersing the polyvinyl alcohol resin layer of the dyed film in a solution containing a crosslinking agent to form a polarizer layer; and drying the crosslinked film.

Description

  The present invention relates to a method for producing a polarizing laminate film suitably used as a polarizing plate or a production intermediate thereof.

  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 need for further thinner and lighter polarizing plates.

  For example, in Patent Documents 1 to 4, a thin wall obtained by forming a resin layer made of a polyvinyl alcohol-based resin on one surface of a base film made of a thermoplastic resin, and then performing a stretching treatment, a dyeing treatment, or the like. It is disclosed that a polarizing laminate film having a polarizer layer is used as a polarizing plate or a production intermediate thereof.

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

  In the production of conventional polarizing laminated films, especially when the stretch ratio during stretching is high, the film tears in the stretching direction when the film is wound with a roll such as a nip roll during dyeing of the polyvinyl alcohol resin layer. There was a problem that.

  Then, the objective of this invention is providing the manufacturing method of the light-polarizing laminated film which can suppress well the tear to the extending | stretching direction in a dyeing process.

  The present invention includes a step of forming a polyvinyl alcohol resin layer on one surface of a base film in which a rubber component is dispersed in a thermoplastic resin to obtain a laminated film, and a stretched film by uniaxially stretching the laminated film. A step of obtaining a dyed film by dyeing a polyvinyl alcohol-based resin layer of a stretched film with a dichroic dye, and immersing the polyvinyl alcohol-based resin layer of the dyed film in a solution containing a crosslinking agent to form a polarizer layer Provided is a method for producing a polarizing laminate film comprising a step of forming a crosslinked film and a step of drying the crosslinked film.

  The thermoplastic resin constituting the base film can be, for example, a polypropylene resin such as a propylene homopolymer.

  The rubber component dispersed in the base film is preferably a copolymer containing an ethylene unit. For example, the rubber component is at least one selected from the group consisting of an ethylene unit and a propylene unit, a butene unit, an octene unit, and a styrene unit. It can be a copolymer comprising units. The ethylene unit content in the ethylene copolymer as the rubber component is preferably more than 10% by weight and less than 90% by weight.

  The present invention also provides a polarizing laminate film comprising a base film in which a rubber component is dispersed in a thermoplastic resin, and a polarizer layer having a thickness of 10 μm or less laminated on one surface of the base film. . This polarizing laminated film can be suitably manufactured by the method according to the present invention.

  According to the present invention, in addition to being able to provide a thin polarizing laminated film having a thin polarizer layer, a thermoplastic resin film in which a rubber component is dispersed is used as a base film. The polarizing laminate film can be produced stably and with good yield.

  The polarizing laminated film of the present invention can be suitably applied as a polarizing plate for a liquid crystal display device used for a liquid crystal display device, for example, a mobile terminal, or a production intermediate thereof.

It is a schematic sectional drawing which shows an example of the laminated | multilayer film obtained at a lamination process. It is a schematic sectional drawing which shows an example of the stretched film obtained at a extending process. It is a schematic sectional drawing which shows an example of the dyeing | staining film obtained at a dyeing process. It is a schematic sectional drawing which shows an example of the crosslinked film obtained at a bridge | crosslinking process. It is a schematic sectional drawing which shows an example of a light-polarizing laminated film. It is a schematic sectional drawing which shows an example of a polarizing plate with a protective film.

<Method for producing polarizing laminated film>
The manufacturing method of the light-polarizing laminated film which concerns on this invention includes the following process.

(A) a laminating step of obtaining a laminated film by forming a polyvinyl alcohol-based resin layer on one surface of a base film in which a rubber component is dispersed in a thermoplastic resin;
(B) A stretching process for uniaxially stretching the laminated film to obtain a stretched film;
(C) a dyeing process of obtaining a dyed film by dyeing a polyvinyl alcohol resin layer of a stretched film with a dichroic dye;
(D) A crosslinking step of immersing the polyvinyl alcohol resin layer of the dyed film in a solution containing a crosslinking agent to form a polarizer layer to obtain a crosslinked film, and (e) a drying step of drying the crosslinked film.

  The base film used in the present invention has a high tear strength even after being stretched at a high magnification in the stretching step (b) by dispersing the rubber component, and thus a dyeing step for dyeing the stretched film. The resistance to tearing of the film in the stretching direction in (c) is effectively improved. The present invention is also advantageous in that a desired effect can be obtained without increasing the number of manufacturing steps. Hereinafter, the manufacturing method of the light-polarizing laminated film of this invention is demonstrated in detail, referring FIGS.

(A) Lamination process In this process, with reference to FIG. 1, the film in which the rubber component is disperse | distributed to the thermoplastic resin (blend dispersion) is made into the base film 10, and the polyvinyl alcohol-type resin layer 20 is provided in the one surface. To obtain a laminated film 100.

(Base film)
The thermoplastic resin that is the base of the base film 10 is preferably a thermoplastic resin that is excellent in transparency, mechanical strength, thermal stability, stretchability, and the like. Specific examples of such thermoplastic resins include, for example, chain polyolefin resins; cyclic polyolefin resins; (meth) acrylic resins; polyester resins; cellulose ester resins; polycarbonate resins; A vinyl acetate resin; a polyarylate resin; a polystyrene resin; a polyethersulfone resin; a polysulfone resin; a polyamide resin; a polyimide resin; and a mixture or copolymer thereof.

  From the viewpoint of handleability of the base film 10, the thermoplastic resin is preferably rigid at room temperature and normal pressure (25 ° C., 101.3 kPa). In the case of an amorphous polymer, the term “rigid” means that the glass transition temperature Tg is higher than normal temperature under normal pressure, and in the case of crystalline polymer, the crystallization melting point Tm is higher than normal temperature under normal pressure. Means. In consideration of being subjected to the stretching step (b), a thermoplastic resin having a Tg or Tm of 100 ° C. or higher is suitable.

  As the chain polyolefin-based resin, since it is easy to stably stretch at a high magnification, a polypropylene-based resin (a polypropylene resin that is a homopolymer of propylene, a copolymer mainly composed of propylene, etc.), a polyethylene-based resin ( A polyethylene resin which is a homopolymer of ethylene, a copolymer mainly composed of ethylene, or the like) is preferably used. The chain polyolefin resin is often crystalline, and the polypropylene resin, which is a homopolymer of propylene, has a crystallization 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 crystallization melting point Tm can vary depending on the density and the like, but is generally in the range of 100 to 140 ° C.

  Heat resistance and flexibility of the base film 10 can be obtained by using a polypropylene resin mainly composed of propylene and copolymerized with other types of monomers, and a polyethylene resin mainly composed of ethylene and other types of monomers copolymerized. Can be improved.

  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.

  Examples of other types of monomers copolymerizable with ethylene include α-olefins. As the α-olefin, in addition to propylene, α-olefins having 4 or more carbon atoms are preferably used, and propylene and α-olefins having 4 to 10 carbon atoms are more preferable.

  Among these, as the polypropylene 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. As the polyethylene resin, an ethylene homopolymer, an ethylene-propylene random copolymer, an ethylene-1-butene random copolymer, and an ethylene-propylene-1-butene random copolymer are preferably used.

  The stereoregularity of the polypropylene resin is preferably substantially isotactic or syndiotactic. The base film made of such a propylene-based resin has relatively good handleability and excellent mechanical strength in a high temperature environment.

  When the chain polyolefin resin is composed of a copolymer of a main monomer and another type of monomer (copolymerization component), the content (copolymerization ratio) of the other type of monomer is preferably small. Is preferably 10% by weight or less, and more preferably 8% by weight or less. If the copolymerization ratio is small, the copolymer will be in a state containing many segments crystallized at room temperature and normal pressure, and it tends to be a rigid resin. On the other hand, when there are too many copolymerization ratios, it may become liquid at normal temperature and a normal pressure, or heat resistance may fall conversely. The copolymerization ratio of other types of monomers in the copolymer can be calculated from the mass balance at the time of polymerization, and is described on page 616 of “Polymer Analysis Handbook” (1995, published by Kinokuniya Shoten). It can be determined by performing infrared (IR) spectrum measurement in accordance with the existing method.

  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 of cyclic polyolefin resins include, for example, ring-opening (co) polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers of cyclic olefins and chain olefins such as ethylene and propylene (typical) Random copolymers), graft polymers obtained by modifying them with unsaturated carboxylic acids or their derivatives, and hydrides thereof. Among these, norbornene resins using norbornene monomers such as norbornene and polycyclic norbornene monomers as cyclic olefins are preferably used.

  Examples of commercial products of cyclic polyolefin resins are “Topas” (manufactured by TOPAS ADVANCED POLYMERS GmbH, available from Polyplastics Co., Ltd.), “Arton” (manufactured by JSR Corporation). ), “ZEONOR” (manufactured by ZEON Corporation), “ZEONEX” (manufactured by ZEON Corporation), “APEL” (manufactured by Mitsui Chemicals, Inc.), and the like.

  Examples of the (meth) acrylic resin include poly (meth) acrylic acid esters such as polymethyl methacrylate, methyl methacrylate- (meth) acrylic acid copolymer, and methyl methacrylate- (meth) acrylic acid ester copolymer. Polymer, methyl methacrylate-acrylic acid ester- (meth) acrylic acid copolymer, methyl (meth) acrylate-styrene copolymer (MS resin, etc.), polymer having an alicyclic hydrocarbon group (for example, methacrylic acid) Methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate- (meth) acrylate norbornyl copolymer, etc.). Preferably, it is a poly (meth) acrylate having 1 to 6 carbon atoms in the alkyl moiety, such as poly (meth) acrylate, more preferably methyl methacrylate as a main component (50 to 100% by weight, The methyl methacrylate resin is preferably 70 to 100% by weight.

  The polyester-based resin is a polymer having an ester bond and can be obtained, for example, by polycondensation of a polyvalent carboxylic acid (including an ester thereof) and a polyhydric alcohol. As the polyvalent carboxylic acid, a divalent carboxylic acid is mainly used, and examples thereof include isophthalic acid, terephthalic acid, dimethyl terephthalate, and dimethyl naphthalenedicarboxylate. As the polyhydric alcohol, dihydric alcohol is mainly used, and examples thereof include propanediol, butanediol, neopentyl glycol, cyclohexanedimethanol and the like. Specific examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexane dimethyl terephthalate, polycyclohexane dimethyl naphthalate, etc. It is. These blend resins and copolymers can also be suitably used.

  The cellulose ester resin is an ester of cellulose and a fatty acid. Specific examples of cellulose ester resins include cellulose triacetate, cellulose diacetate, cellulose tripropionate, cellulose dipropionate, copolymers of these, and some hydroxyl groups modified with other substituents. Things. 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 “Fujitac TD80” (manufactured by Fuji Film Co., Ltd.), “Fujitac TD80UF” (manufactured by Fuji Film Co., Ltd.), “Fujitac TD80UZ” (Fuji Film ( Co., Ltd.), “Fujitac TD40UZ” (Fuji Film Co., Ltd.), “KC8UX2M” (Konica Minolta Opto Co., Ltd.), “KC4UY” (Konica Minolta Opto Co., Ltd.), and the like.

  The polycarbonate resin is an engineering plastic made of a polymer in which monomer units are bonded via a carbonate group, and is a resin having high impact resistance, heat resistance, and flame retardancy. Moreover, since it has high transparency, it is suitably used in optical applications. In optical applications, resins called modified polycarbonates in which the polymer skeleton is modified to lower the photoelastic coefficient, copolymerized polycarbonates with improved wavelength dependency, and the like are also commercially available, and these can also be used suitably. Examples of commercially available polycarbonate resins are all "Panlite" (Teijin Chemicals), "Iupilon" (Mitsubishi Engineering Plastics), "SD Polyca" (Sumitomo Dow) )), “Caliver” (Dow Chemical Co., Ltd.).

  The rubber component dispersed in the thermoplastic resin is a resin component having rubber elasticity, and is usually uniformly dispersed in the thermoplastic resin as rubber particles. By mixing and dispersing the rubber component, it is possible to improve the tear strength of the base film and thus the stretched film. The rubber component is not particularly limited as long as it is a resin having rubber elasticity. However, from the viewpoint of compatibility with the thermoplastic resin, the rubber component is preferably composed of the same or similar resin as the thermoplastic resin to be used.

  For example, when the thermoplastic resin is a chain polyolefin-based resin, the rubber component can be a copolymer of two or more monomers selected from ethylene and α-olefin. In this case, the content (polymerization ratio) of each monomer constituting the copolymer is preferably less than 90% by weight, and more preferably less than 80% by weight. If the content of one monomer unit is excessively high, continuous segments of the monomer unit are likely to be formed, and crystallization tends to occur, resulting in loss of rubber elasticity.

  As the rubber component composed of a copolymer of two or more kinds of monomers, various copolymers including an ethylene unit can be suitably used. Among them, in addition to the ethylene unit, a propylene unit, a butene unit, an octene unit can be used. And a copolymer containing one or more units selected from the group consisting of styrene units is more preferably used. The ethylene unit content (polymerization ratio) in the copolymer is preferably more than 10% by weight and less than 90% by weight, more preferably 20% by weight or more and 80% by weight or less, and further preferably 25% by weight or more and 70% by weight. % Or less. In one preferred embodiment of the base film used in the present invention, a polypropylene resin (for example, propylene homopolymer) is used as the thermoplastic resin, and a copolymer containing ethylene units as the rubber component in the above content is used. It is dispersed.

  The content of the ethylene unit in the copolymer can be calculated from the mass balance at the time of polymerization, and the method described on page 616 of the “Polymer Analysis Handbook” (published by Kinokuniya, 1995). According to the above, it can be obtained by performing infrared (IR) spectrum measurement.

  When the thermoplastic resin is a (meth) acrylic resin, it is preferable to contain an acrylic polymer having rubber elasticity as a rubber component from the viewpoint of compatibility. The acrylic polymer is preferably a polymer mainly composed of alkyl acrylate, and may be a homopolymer of alkyl acrylate. Alkyl acrylate is 50% by weight or more and other monomer is 50% by weight or less. And a copolymer thereof.

  As the alkyl acrylate, those having 4 to 8 carbon atoms in the alkyl group are usually used. Examples of other monomers include monofunctional monomers such as alkyl methacrylates such as methyl methacrylate and ethyl methacrylate, styrene monomers such as styrene and alkylstyrene, and unsaturated nitriles such as acrylonitrile and methacrylonitrile. In addition, alkenyl esters of unsaturated carboxylic acids such as allyl (meth) acrylate and methallyl (meth) acrylate, dialkenyl esters of dibasic acids such as diallyl maleate, and alkylene glycol di (meth) acrylate And polyfunctional monomers such as unsaturated carboxylic acid diesters of glycols.

  The rubber component containing the acrylic polymer is preferably in the form of particles, and more preferably particles having a multilayer structure having an acrylic polymer layer. It may have a two-layer structure having a polymer layer mainly composed of alkyl methacrylate outside the acrylic polymer layer (core), and further, the alkyl methacrylate inside the acrylic polymer layer. It may have a three-layer structure having a polymer layer (core) mainly composed of. The acrylic rubber particles having a multilayer structure can be produced, for example, by the method described in JP-B-55-27576.

  The blending amount of the rubber component is preferably 5 to 50% by weight of the thermoplastic resin, more preferably 10 to 45% by weight. When the blending amount of the rubber component is too small, it is difficult to obtain a sufficient effect of improving the tear strength, and when the blending amount of the rubber component is too large, the handleability of the base film tends to be lowered.

  The method for dispersing the rubber component in the thermoplastic resin is not particularly limited. For example, the thermoplastic resin and the rubber component (rubber particles) produced separately are kneaded and dispersed with a plastmill or the like, or the same reaction when preparing the thermoplastic resin. Examples thereof include a reactor blend method in which a rubber component is also prepared in a container to obtain a thermoplastic resin in which the rubber component is dispersed. The reactor blending method is advantageous in improving the degree of dispersion of the rubber component.

  Any appropriate additive may be added to the base film 10 in addition to the thermoplastic resin and the rubber component. Examples of such additives include compatibilizers for improving the dispersibility of rubber components, UV absorbers, antioxidants, lubricants, plasticizers, mold release agents, anti-coloring agents, flame retardants, and nucleating agents. , Antistatic agents, pigments, and colorants. The total content of the thermoplastic resin and the rubber component 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. %. When the total content is less than 50% by weight, the high transparency inherent in the thermoplastic resin may not be sufficiently exhibited.

  As the compatibilizing agent, those having a low molecular weight can be used, but it is more preferable to use a compatibilizing agent composed of a polymer because of concerns such as bleeding. Examples of the compatibilizer made of a polymer include a block copolymer, and specifically include a styrene-ethylene-butene-styrene block copolymer.

  The thickness (before stretching) of the base film 10 in the laminated film 100 is not particularly limited, but is preferably 1 to 500 μm, more preferably 1 to 300 μm, and further preferably 5 to 200 μm from the viewpoint of workability such as strength and handleability. Preferably, 5 to 150 μm is most preferable.

  In order to improve the adhesion with the polyvinyl alcohol-based resin layer 20 on the surface of the base film 10 on which the polyvinyl alcohol-based resin layer 20 is formed, the adhesion is improved by corona treatment, plasma treatment, flame treatment, etc. You may process and may form thin layers, such as a primer layer and an adhesive bond layer.

(Polyvinyl alcohol resin layer)
As a polyvinyl alcohol-type resin which forms the polyvinyl alcohol-type resin layer 20, a polyvinyl alcohol resin and its derivative (s) are mentioned, for example. 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 these, it is preferable to use a polyvinyl alcohol resin.

  The polyvinyl alcohol resin is preferably a completely saponified product. The range of the saponification degree is preferably 80.0 to 100.0 mol%, more preferably 90.0 to 99.5 mol%, still more preferably 94.0 to 99.0 mol%. . When the degree of saponification is less than 80.0 mol%, there is a problem that the water resistance and heat-and-moisture resistance after the polarizing laminated film are remarkably inferior. In addition, when a polyvinyl alcohol-based resin having a saponification degree exceeding 99.5 mol% is used, the dyeing speed is remarkably slow, and a polarizing laminated film having sufficient polarization performance may not be obtained. In some cases, the production takes several times longer than usual.

  The saponification degree as used herein is a unit ratio (mol%) representing the ratio of the acetate group contained in the polyvinyl acetate resin, which is a raw material for the polyvinyl alcohol resin, to a hydroxyl group by the saponification step. Is a numerical value defined by the following formula. It can be determined by the method defined in JIS K 6726 (1994).

Saponification degree (mol%) = (number of hydroxyl groups) ÷ (number of hydroxyl groups + number of acetate groups) × 100
The average degree of polymerization of the polyvinyl alcohol-based resin is not particularly limited, but is preferably 100 to 10,000, more preferably 1500 to 8000, and most preferably 2000 to 5000. The average degree of polymerization here is also a numerical value determined by a method defined by JIS K 6726 (1994).

  If necessary, additives such as a plasticizer and a surfactant may be added to the polyvinyl alcohol-based resin described above. 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 amount of the additive is not particularly limited, but is preferably 20% by weight or less of the polyvinyl alcohol resin.

  The polyvinyl alcohol-based resin layer 20 is preferably such that a polyvinyl alcohol-based resin solution obtained by dissolving a polyvinyl alcohol-based resin in a good solvent is applied to one surface of the base film 10 and the solvent is evaporated by drying. Formed by. According to such a method, the polyvinyl alcohol-based resin layer 20 can be formed thin. As a method of applying the polyvinyl alcohol resin solution to the base film 10, a roll coating method such as a wire bar coating method, reverse coating, and gravure coating, spin coating method, screen coating method, fountain coating method, dipping method, spraying It can select suitably from well-known methods, such as a method. A drying temperature is 50-200 degreeC, for example, Preferably it is 60-150 degreeC. The drying time is, for example, 2 to 20 minutes.

  As described above, before forming the polyvinyl alcohol-based resin layer 20, a primer layer is previously formed on the surface of the base film 10 on the side where the polyvinyl alcohol-based resin layer 20 is formed in order to improve adhesion. You may form. The primer layer can be formed, for example, by applying a solution containing a polyvinyl alcohol-based resin and a crosslinking agent in the same manner as described above and drying.

  In addition, although the polyvinyl alcohol-type resin layer 20 can also be formed by sticking the film which consists of polyvinyl alcohol-type resin on the base film 10, in this case, an adhesive agent is used for sticking between films. be able to.

  The thickness of the polyvinyl alcohol-based resin layer 20 in the laminated film 100 is preferably 3 μm to 50 μm, and more preferably 5 μm to 45 μm. If it is 3 μm or less, it becomes too thin after stretching and the dyeability is significantly deteriorated. If it exceeds 50 μm, the resulting polarizing laminate film becomes thick.

(B) Stretching step This step is a step of obtaining a stretched film 200 by uniaxially stretching the laminated film 100 including the base film 10 and the polyvinyl alcohol-based resin layer 20 (see FIG. 2). The draw ratio of the laminated film 100 can be appropriately selected according to the desired polarization characteristics, but is preferably more than 5 times and 17 times or less, more preferably more than 5 times 8 times the original length of the laminated film 100. Is less than double. When the draw ratio is 5 times or less, the stretched polyvinyl alcohol-based resin layer 20 ′ is not sufficiently oriented, and as a result, the polarization degree of the polarizer layer is not sufficiently high. On the other hand, when the draw ratio exceeds 17 times, the film is easily broken at the time of drawing, and at the same time, the thickness of the film becomes unnecessarily thin, and the workability and handleability in subsequent steps may be reduced. In the present invention, since the base film 10 in which the rubber component as described above is dispersed is used, the obtained stretched film 200 is resistant to tearing in the stretching direction even when the stretch ratio is more than 5 times. High resistance. Therefore, according to the present invention, it is possible to provide a polarizing laminated film having high polarization characteristics and high durability.

  The uniaxial stretching treatment is not limited to stretching in one stage, and can be performed in multiple stages. In this case, it is preferable to perform the stretching treatment so as to obtain a stretching ratio of more than 5 times by combining all stages of the stretching treatment.

  Uniaxial stretching is preferably longitudinal stretching in which stretching is performed in the longitudinal direction (film transport direction) of the laminated film 100. Examples of the longitudinal stretching method include an inter-roll stretching method, a compression stretching method, and a stretching method using a tenter. The uniaxial stretching is not limited to the longitudinal stretching process, and may be oblique stretching or the like.

  As the stretching treatment, either a wet stretching method or a dry stretching method can be adopted. However, the use of the dry stretching method is preferable in that the temperature during stretching can be selected from a wide range.

  The stretching temperature is set in the vicinity of the glass transition temperature Tg or the crystallization melting point Tm of the base film, preferably in the range of [(Tg or Tm) -30 ° C.] to [(Tg or Tm) + 15 ° C.], more Preferably, it is in the range of [(Tg or Tm) −25 ° C.] to [Tg or Tm]. If the stretching temperature is lower than [(Tg or Tm) -30 ° C.], it becomes difficult to stretch at a high magnification exceeding 5 times. If the stretching temperature exceeds [(Tg or Tm) + 15 ° C.], the fluidity of the base film 10 is too high and stretching tends to be difficult. In addition, extending | stretching temperature is in the said range, More preferably, it is 120 degreeC or more. This is because when the stretching temperature is 120 ° C. or higher, there is no difficulty in the stretching treatment even at a high stretching ratio of more than 5 times. The temperature adjustment of the stretching process is usually based on the temperature adjustment of the heating furnace.

  When the thickness of the laminated film 100 is within the above range, the thickness of the uniaxially stretched base film 10 ′ in the stretched film 200 is usually 1 to 300 μm, preferably 1 to 100 μm. In addition, the thickness of the uniaxially stretched polyvinyl alcohol resin layer 20 ′ in the stretched film 200 is preferably 1 to 10 μm, and more preferably 2 to 8 μm. If the thickness of the polyvinyl alcohol-based resin layer 20 ′ is 1 μm or less, it is too thin and the dyeability is remarkably deteriorated. If it exceeds 10 μm, the resulting polarizing laminate film is thick.

(C) Dyeing process This process is a process of obtaining the dyed film 300 by dyeing the polyvinyl alcohol resin layer 20 ′ of the stretched film 200 with a dichroic dye (see FIG. 3). Examples of the dichroic dye 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. These dichroic substances may be used alone or in combination of two or more.

  A dyeing process can be performed by immersing the stretched film 200 whole in the solution (dyeing solution) containing the said dichroic dye, for example. As the staining solution, a solution in which the above dichroic dye 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 dye 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 dye, 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 iodide concentration in the dyeing solution is preferably 0.01 to 20% by weight. 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. A range of 1: 7 to 1:70 is particularly preferable.

  The immersion time of the stretched film 200 in the dyeing solution is not particularly limited, but is preferably in the range of 15 seconds to 15 minutes, and more preferably 30 seconds 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.

  Although the dyeing process can be performed before or simultaneously with the stretching process, the stretching process is performed on the laminated film 100 so that the dichroic dye adsorbed on the polyvinyl alcohol-based resin layer can be favorably oriented. It is preferable to carry out after this.

(D) Crosslinking step In this step, the polyvinyl alcohol resin layer 30 of the dyed film 300 obtained by dyeing with a dichroic dye is subjected to a crosslinking treatment, and the polyvinyl alcohol resin layer is used as the polarizer layer 40. This is a step of obtaining a crosslinked film 400 (see FIG. 4). The crosslinking step can be performed, for example, by immersing the dyed film 300 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. These may be used alone or in combination of two or more.

  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. The concentration of the crosslinking agent in the crosslinking solution is preferably in the range of 1 to 20% by weight, more preferably 6 to 15% by weight.

  Iodide may be added to the crosslinking solution. By adding iodide, the polarization characteristics in the plane of the polarizer layer 40 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 concentration of iodide is preferably 0.05 to 15% by weight, more preferably 0.5 to 8% by weight.

  The immersion time of the dyed film 300 in the crosslinking solution is preferably 15 seconds to 20 minutes, and more preferably 30 seconds to 15 minutes. Moreover, it is preferable that the temperature of a crosslinking solution exists in the range of 10-90 degreeC.

  In addition, a bridge | crosslinking process can also be performed simultaneously with a dyeing process by mix | blending a crosslinking agent in a dyeing solution. Moreover, you may perform a bridge | crosslinking process and an extending process simultaneously.

(E) Drying step The obtained crosslinked film 400 is usually washed and then dried. Thereby, a light-polarizing laminated film is obtained (refer to Drawing 5). The washing can be performed by immersing the crosslinked film 400 in pure water such as ion exchange water or 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. The washing may be a combination of a washing treatment with an iodide solution and a water washing treatment, and a solution in which a liquid alcohol such as methanol, ethanol, isopropyl alcohol, butanol, propanol or the like is appropriately blended may be used.

  Any appropriate method (for example, natural drying, air drying, heat drying) can be adopted as the drying method. 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.

  The polarizing laminated film includes a polarizer layer 40 composed of a polyvinyl alcohol-based resin layer in which a dichroic dye is adsorbed and oriented, and can itself be used as a polarizing plate. According to the method of the present invention, since the thickness of the polarizer layer 40 can be made 10 μm or less, a thin polarizing laminated film can be obtained. Moreover, the polarizing laminated film of this invention is excellent also in polarizing performance and durability.

<Method for producing polarizing plate with protective film>
The polarizing laminate film is useful as an intermediate for producing a polarizing plate having a protective film attached thereto, and by using this, a polarizing plate with a protective film can be efficiently produced with a high yield. . An example of a polarizing plate with a protective film is shown in FIG. The polarizing plate 600 with a protective film shown in the figure has a protective film 50 on the opposite side of the surface of the polarizer layer 40 on which the stretched base film 10 ′ is laminated. In the example of FIG. 6, the base film 10 ′ is peeled and removed, but the polarizing plate with a protective film may have the base film 10 ′.

  A polarizing plate with a protective film can be produced by a method including the following steps using the polarizing laminated film.

(A) The process of bonding the protective film 50 to the surface on the opposite side to the base film 10 'side in the polarizer layer 40 of the polarizing laminated film 500,
(B) A step of peeling and removing the base film 10 ′. Step (B) is an optional step as described above.

  The protective film 50 can be comprised from the resin similar to the resin mentioned above as a thermoplastic resin which comprises a base film. The protective film 50 may be provided with a phase difference by uniaxial stretching or biaxial stretching.

  The protective film 50 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 are caused. Therefore, the thickness of the protective film 50 is preferably 80 μm or less, and more preferably 5 to 60 μm. Further, from the viewpoint of reducing the thickness of the polarizing plate with a protective film, the total thickness of the polarizer layer 40 and the protective film 50 is preferably 100 μm or less, more preferably 90 μm or less, and still more preferably 80 μm or less.

  An optical layer such as a hard coat layer, an antiglare layer, a light diffusion layer, or an antireflection layer can be formed on the surface of the protective film 50 opposite to the polarizer layer 40.

  Bonding of the polarizer layer 40 and the protective film 50 can be performed using an adhesive or an adhesive. Examples of the adhesive include aqueous adhesives such as an aqueous polyvinyl alcohol resin solution and an aqueous two-component urethane emulsion adhesive. When using the cellulose ester-type resin film hydrophilized by the saponification process etc. as the protective film 50, polyvinyl alcohol-type resin aqueous solution is used suitably as an adhesive agent. 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.

  The method of bonding the polarizer layer 40 and the protective film 50 using a water-based adhesive is not particularly limited. For example, casting method, Mayer bar coating method, gravure coating method, comma coater method, doctor plate method The adhesive is uniformly applied to the surface of the polarizer layer 40 and / or the protective film 50 by die coating, dip coating, spraying, etc., and the other film is laminated on the coated surface and pasted using a roll or the like. And a method of drying. In the casting method, the polarizer layer 40 or the protective film 50, which is an object to be coated, is moved in a substantially vertical direction, a substantially horizontal direction, or an oblique direction between the two, and an adhesive is allowed to flow onto the surface. This is a method of spreading.

  After bonding the polarizer layer 40 and the protective film 50, the laminated film is dried in order to remove water contained in the aqueous adhesive. The drying temperature is preferably 30 to 90 ° C. If it is lower than 30 ° C., the polarizer layer 40 and the protective film 50 tend to be peeled off easily. Moreover, there exists a possibility that polarization performance may deteriorate with heat that it is 90 degreeC or more. The drying time can be 10 to 1000 seconds, and particularly from the viewpoint of productivity, it is preferably 60 to 750 seconds, 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 curing temperature is generally set lower than the temperature adopted during drying.

  A photo-curable adhesive can also be used as an adhesive when the polarizer layer 40 and the protective film 50 are bonded together. As a photocurable adhesive agent, the mixture of a photocurable epoxy resin and a photocationic polymerization initiator can be mentioned, for example.

  When using a photocurable adhesive, after bonding the polarizer layer 40 and the protective film 50 in the same manner as described above, the photocurable adhesive is cured by irradiating active energy rays. 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 risk of yellowing of the resin and deterioration of the polarizer layer. 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, the irradiation time is not too long and good productivity can be maintained.

  In addition, in bonding of the polarizer layer 40 and the protective film 50, plasma treatment, corona treatment, and ultraviolet irradiation treatment are performed on the adhesive surface of the polarizer layer 40 and / or the protective film 50 in advance in order to improve adhesion. Surface treatment such as flame (flame) treatment or saponification treatment may be performed as necessary. Examples of the saponification treatment include a method of immersing in an aqueous alkali solution such as sodium hydroxide or potassium hydroxide.

  On the other hand, the pressure-sensitive adhesive used for bonding the polarizer layer 40 and the protective film 50 usually uses an acrylic resin, a styrene resin, a silicone resin, or the like as a base polymer, and an isocyanate compound, an epoxy compound, or aziridine. It consists of a composition to which a crosslinking agent such as a compound 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 is preferably formed as thin as possible without impairing workability and durability, and more preferably 3 to 25 μm. When the thickness of the pressure-sensitive adhesive layer is less than 1 μm, the adhesiveness is lowered, and when it exceeds 40 μm, problems such as the pressure-sensitive adhesive protruding easily occur.

  The method of bonding the polarizer layer 40 and the protective film 50 with the adhesive is not particularly limited, and a solution (adhesive) containing each component including the above-described base polymer on the protective film surface or the polarizer layer surface. After the adhesive composition is applied and dried to form an adhesive layer, the polarizer layer 40 and the protective film 50 may be bonded together, or after the adhesive layer is formed on the separator (release film) The polarizer layer 40 and the protective film 50 may be bonded together by transferring to the protective film surface or the polarizer layer surface.

  In addition, in order to improve adhesiveness, surface treatments, such as a corona treatment, may be previously performed on the bonding surface of the polarizer layer 40 and / or the protective film 50, or one or both surfaces of the pressure-sensitive adhesive layer as necessary. Good.

  The step (B) is a step of peeling and removing the base film 10 ′ from the laminate including the base film 10 ′ / polarizer layer 40 / protective film 50 obtained in the step (A). After the protective film 50 is bonded, the base film 10 ′ may be peeled off as it is, or after the protective film 50 is bonded, the base film 10 is wound up in a roll and then unwound in a subsequent process. 'May be peeled off.

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

(Preparation of polarizing laminated film)
<Example 1>
(1) Production of base film A thermoplastic resin and a rubber component were sequentially prepared in the same reaction vessel by a reactor blend method. Specifically, propylene monomer was fed in the gas phase as a first step using a Ziegler-Natta type catalyst to produce a propylene homopolymer as a thermoplastic resin. After stopping the reaction by stopping the propylene monomer feed, the ethylene monomer and the propylene monomer are fed into the reaction vessel as they are in the gas phase as the second step, and the ethylene-propylene copolymer as a rubber component is fed. Propylene homopolymer produced by dispersing ethylene-propylene copolymer, which is a rubber component, in the form of particles was obtained. The ethylene unit content in the copolymer was determined from the material balance during polymerization and found to be 35% by weight. Further, the content of ethylene units in the entire resin (total of thermoplastic resin and rubber component) is determined according to the method described on page 616 of the Polymer Handbook (published by Kinokuniya Shoten in 1995), and the resin is determined from this value. When the content of the ethylene-propylene copolymer in the whole was calculated, it was 29% by weight (that is, the content of the ethylene-propylene copolymer was 40.8% by weight of the thermoplastic resin).

  The obtained mixed resin was melt-kneaded at 250 ° C. and then melt-extruded at a temperature of 280 ° C. with a T die to obtain a base film having a thickness of 100 μm.

(2) Formation of primer layer Polyvinyl alcohol powder (“Z-200” manufactured by Nippon Synthetic Chemical Industry Co., Ltd., average polymerization degree 1100, average saponification degree 99.5 mol%) was dissolved in 95 ° C. hot water, A polyvinyl alcohol aqueous solution having a concentration of 3% by weight was prepared. The resulting aqueous solution was mixed with 5 parts by weight of a crosslinking agent (“SUMIREZ RESIN 650” manufactured by Sumitomo Chemical Co., Ltd.) with respect to 6 parts by weight of polyvinyl alcohol powder. The obtained mixed aqueous solution was applied onto the corona-treated surface of the base film subjected to the 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. Formed.

(3) Formation of polyvinyl alcohol resin layer Polyvinyl alcohol powder (“PVA124” manufactured by Kuraray Co., Ltd., average polymerization degree 2400, average saponification degree 98.0-99.0 mol%) is dissolved in hot water at 95 ° C. An aqueous polyvinyl alcohol solution having a concentration of 8% by weight was prepared. The obtained aqueous solution was coated on the primer layer using a lip coater, and dried under conditions of 80 ° C. for 2 minutes, 70 ° C. for 2 minutes, and then 60 ° C. for 4 minutes, whereby a base film A laminated film having a polyvinyl alcohol resin layer laminated thereon with a primer layer interposed therebetween was produced. The thickness of the polyvinyl alcohol-based resin layer was 9.8 μm.

(4) Production of stretched film The laminated film was uniaxially stretched 5.8 times at a stretching temperature of 160 ° C. to obtain a stretched film. The obtained stretched film had a thickness of 28.5 μm, and the polyvinyl alcohol resin layer had a thickness of 4.2 μm.

(5) Preparation of polarizing laminated film The stretched film was immersed in a 60 ° C. warm bath for 60 seconds, and then immersed in a dyeing solution at 30 ° C., which is an aqueous solution containing iodine and potassium iodide, for about 150 seconds. The system resin layer was dyed, and then the excess iodine solution was washed away with 10 ° C. pure water. Next, it was immersed for 600 seconds in the 76 degreeC bridge | crosslinking solution which is the aqueous solution containing a boric acid and potassium iodide. 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.

  In each step up to the production of the polarizing laminated film, problems such as tearing of the film after stretching did not occur, and the polarizing laminated film could be produced stably.

<Example 2>
Example 1 except that ethylene monomer and 1-butene monomer were fed to prepare an ethylene-butene copolymer as a rubber component in the second step of “(1) Production of substrate film” in Example 1. In the same manner, a base film having a thickness of 100 μm was produced. The content of ethylene units in the copolymer was 35% by weight. The ethylene unit content in the entire resin was 30% by weight (that is, the ethylene-propylene copolymer content was 42.9% by weight of the thermoplastic resin).

  Using the base film thus obtained, a polarizing laminated film was produced in the same manner as in Example 1. In each step up to the production of the polarizing laminated film, problems such as tearing of the film after stretching did not occur, and the polarizing laminated film could be produced stably.

<Comparative Example 1>
Except having used the 100-micrometer-thick base film (without rubber component) which consists of propylene homopolymers ("Sumitomo Noblen FLX80E4" by Sumitomo Chemical Co., Ltd., melting | fusing point Tm = 163 degreeC), it carried out similarly to Example 1 A laminated film was produced. Next, free end longitudinal uniaxial stretching was performed under the same conditions as in Example 1 to obtain a stretched film having a thickness of 30.1 μm. The thickness of the polyvinyl alcohol resin layer in the stretched film was 4.5 μm.

<Comparative example 2>
A base film (no rubber component) having a thickness of 100 μm made of a propylene-ethylene random copolymer (“Sumitomo Noblen W151” manufactured by Sumitomo Chemical Co., Ltd., melting point Tm = 138 ° C.) containing about 5% by weight of ethylene units was used. A laminated film was produced in the same manner as in Example 1 except that. Next, free end longitudinal uniaxial stretching was performed under the same conditions as in Example 1 to obtain a stretched film having a thickness of 30.1 μm. The thickness of the polyvinyl alcohol resin layer in the stretched film was 4.5 μm.

(Measurement of tear strength of stretched film)
The tear strength of the stretched films obtained in the above examples and comparative examples was measured by the following method. First, from the center of the short side edge part of the stretched film (the center in the film width direction), a cut was made in parallel with the stretching direction using a cutter. Next, using a universal tensile testing machine ("Autograph AG-I" manufactured by Shimadzu Corporation), the stretched film was torn from the base point of the cut, and the tear strength at that time was measured using the same apparatus. The film tearing speed was 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). Until the angle stabilizes, the tear strength often increases. Therefore, in this measurement, this portion was excluded, and an average value of the tear strength in a region where the tear strength was stable was obtained, and this was taken as the tear strength. The results are shown in Table 1.

  As shown in Table 1, it was confirmed that the stretched films of Examples 1 and 2 had higher resistance to tearing in the stretching direction than Comparative Examples 1 and 2.

[Preparation of polarizing plate with protective film]
<Example 3>
Using each of the polarizing laminate films obtained in Examples 1 and 2, a polarizing plate with a protective film was produced by the following procedure. First, polyvinyl alcohol powder (“KL-318” manufactured by Kuraray Co., Ltd., average polymerization degree 1800) was dissolved in hot water at 95 ° C. to prepare a polyvinyl alcohol aqueous solution having a concentration of 3% by weight. The resulting aqueous solution was mixed with 1 part by weight of a crosslinking agent (“SUMIREZ RESIN 650” manufactured by Sumitomo Chemical Co., Ltd.) with respect to 2 parts by weight of polyvinyl alcohol powder to obtain an adhesive solution.

  Next, after applying the adhesive solution on the polyvinyl alcohol resin layer of the polarizing laminated film, a protective film made of triacetyl cellulose (TAC) (“KC4UY” manufactured by Konica Minolta Opto Co., Ltd.) is bonded. Thus, a polarizing plate comprising 5 layers of protective film / adhesive layer / polarizer layer / primer layer / base film was obtained. The base film was peeled from the obtained polarizing plate to prepare a polarizing plate comprising 4 layers of protective film / adhesive layer / polarizer layer / primer layer. The base film could be easily peeled off.

  DESCRIPTION OF SYMBOLS 10 Base film, 10 'Stretched base film, 20 Polyvinyl alcohol-type resin layer, 20' Stretched polyvinyl alcohol-type resin layer, 30 Polyvinyl alcohol-type resin layer dye | stained with dichroic dye, 40 Polarizer Layer, 50 protective film, 100 laminated film, 200 stretched film, 300 dyed film, 400 crosslinked film, 500 polarizing laminated film, 600 polarizing plate with protective film.

Claims (7)

Forming a polyvinyl alcohol resin layer on one surface of a base film in which a rubber component is dispersed in a thermoplastic resin to obtain a laminated film;
Uniaxially stretching the laminated film to obtain a stretched film;
Dyeing the polyvinyl alcohol-based resin layer of the stretched film with a dichroic dye to obtain a dyed film;
Immersing the polyvinyl alcohol-based resin layer of the dyed film in a solution containing a crosslinking agent to form a polarizer layer, and obtaining a crosslinked film;
Drying the crosslinked film;
The manufacturing method of the polarizing laminated film containing this.   The method for producing a polarizing laminated film according to claim 1, wherein the thermoplastic resin is a polypropylene resin.   The method for producing a polarizing laminated film according to claim 1, wherein the thermoplastic resin is a propylene homopolymer.   The method for producing a polarizing laminated film according to claim 1, wherein the rubber component is a copolymer containing an ethylene unit.   The polarizing laminate film according to claim 4, wherein the rubber component is a copolymer including an ethylene unit and one or more units selected from the group consisting of a propylene unit, a butene unit, an octene unit, and a styrene unit. Production method.   The method for producing a polarizing laminated film according to claim 4 or 5, wherein a content of the ethylene unit in the copolymer is more than 10% by weight and less than 90% by weight.   A polarizing laminated film comprising: a base film in which a rubber component is dispersed in a thermoplastic resin; and a polarizer layer having a thickness of 10 μm or less laminated on one surface of the base film.

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