TW201307069A - Method for producing polarizing laminate film - Google Patents

Abstract

The present invention provides a method for producing polarizing laminate film having a base film comprising a thermoplastic resin in which a rubber component is dispersed and a polarizer layer which is laminated on one surface of the base film, wherein the method comprises: a step of obtaining a laminate film by forming a polyvinyl alcohol resin layer on one surface of a base film comprising a thermoplastic resin in which a rubber component is dispersed; a step of obtaining a stretched film by uniaxially stretching the laminate film; a step of obtaining a colored film by coloring the polyvinyl alcohol resin layer of the stretched film with a dichroic colorant; a step of obtaining a cross-linked film by forming a polarizer layer from the polyvinyl alcohol resin layer by immersing the polyvinyl alcohol resin layer in a solution containing a cross-linking agent and then cross-linking the polyvinyl alcohol resin; and a step of drying the cross-linked film.

Description

Method for producing polarizing laminated film

The present invention relates to a method for producing a polarizing laminated film which is suitable for use as a polarizing plate or an intermediate thereof.

The polarizing plate is widely used as a polarizing supply element or a polarized detecting element in a liquid crystal display device. The polarizing plate has been a protective film composed of cellulose triacetate or the like on one surface or both surfaces of a polarizing film made of a polyvinyl alcohol-based resin. In recent years, a notebook personal person accompanying a liquid crystal display device has been used. With regard to the development of mobile devices such as computers and mobile phones, and the development of large-scale televisions, polarizers have been required to be thinner and lighter.

For example, in JP-2000-338329-A, JP-2009-93074-A, JP-2009-98653-A, and JP-2003-43257-A, it is disclosed in a substrate film composed of a thermoplastic resin. A resin layer made of a polyvinyl alcohol-based resin is formed on one surface, and then subjected to a stretching treatment and a dyeing treatment to obtain a polarizing laminate film containing a thin polarizer layer, and used as a polarizing plate or an intermediate thereof.

In the production of the polarizing laminated film of the related art, particularly in the case where the stretching ratio at the time of the stretching treatment is high, when the polyvinyl alcohol-based resin layer is dyed, the film may be taken up by a roll such as a nip roll. The problem of cracking of the film in the direction of extension.

Accordingly, an object of the present invention is to provide a method for producing a polarizing laminated film which can satisfactorily suppress fragmentation in a stretching direction in a dyeing step.

The present invention encompasses the following items.

[1] A method for producing a polarizing laminated film comprising: a base film obtained by dispersing a rubber component in a thermoplastic resin; and a polarizer layer laminated on one side of the base film. The production method includes a step of forming a polyvinyl alcohol-based resin layer on one surface of a base film formed by dispersing a rubber component in a thermoplastic resin to obtain a laminated film, and stretching the laminated film to a uniaxial direction to obtain an expanded film. a step of dyeing the polyvinyl alcohol-based resin layer of the stretched film with a dichroic dye to obtain a dyed film; and immersing the polyvinyl alcohol-based resin layer of the dyed film in a solution containing a crosslinking agent, a step of crosslinking the polyvinyl alcohol-based resin, forming a polarizer layer from the polyvinyl alcohol-based resin layer to obtain a crosslinked film, and drying the crosslinked film.

[2] The method for producing a polarizing laminate film according to [1], wherein the thermoplastic resin is a polypropylene resin.

[3] The method for producing a polarizing laminate film as set forth in [1], wherein the thermoplastic resin is a polymer of propylene alone.

[4] The method for producing a polarizing laminated film according to any one of [1] to [3] wherein the rubber component is a copolymer containing an ethylene unit.

[5] The method for producing a polarizing laminate film as set forth in [4], wherein the rubber component contains ethylene unit, propylene unit, butene unit, octene unit A copolymer of one or more units selected from the group consisting of a unit and a styrene unit.

[6] The method for producing a polarizing laminate film as set forth in [4] or [5], wherein the content of the aforementioned ethylene unit in the copolymer exceeds 10% by weight and is less than 90% by weight.

[7] A polarizing laminate film comprising a base material 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 side of the base film.

According to the present invention, in addition to providing a thin polarizing layer film having a thin layer of a polarizer layer, and using a thermoplastic resin film in which a rubber component is dispersed as a base film, it is possible to effectively suppress the stretching direction in the dyeing step. The rupture can produce a polarizing laminate film with excellent yield and stability.

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

<Method for Producing Polarized Laminated Film>

The method for producing a polarizing laminate film of the present invention comprises the following steps.

(a) a step of forming a polyvinyl alcohol-based resin layer on one side of a base film obtained by dispersing a rubber component in a thermoplastic resin to obtain a laminated film; (b) uniaxially stretching the laminated film to obtain a stretched film The step of stretching; (c) dyeing the polyvinyl alcohol-based resin layer of the stretched film with dichroic dye a dyeing step of obtaining a dyed film; (d) immersing the polyvinyl alcohol-based resin layer of the dyed film in a solution containing a crosslinking agent to crosslink the polyvinyl alcohol-based resin to form a polyvinyl alcohol-based resin layer a polarizing member layer to obtain a crosslinking step of the crosslinked film; and (e) a drying step of drying the crosslinked film.

Since the base film used in the present invention has a rubber component dispersed therein, even if it has a high tensile strength after being stretched at a high magnification in the stretching step (b), the dyeing step of the dyeing of the stretched film can be effectively improved ( c) Crack resistance of the film in the direction of the medium extension. This is advantageous in that the present invention does not increase the number of manufacturing steps and also achieves the desired effect. Hereinafter, the method for producing the polarizing laminated film of the present invention will be described in detail with reference to the first to fourth drawings.

(a) Lamination step

In this step, referring to Fig. 1, a film composed of a rubber component dispersed (mixed and dispersed) in a thermoplastic resin is used as the base film 10, and a polyvinyl alcohol-based resin layer 20 is formed on one surface thereof to obtain a laminated film. 100.

(substrate film)

The thermoplastic resin forming the base of the base film 10 is preferably a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, and ductility. Specific examples of such a thermoplastic resin include a linear polyolefin resin; a cyclic polyolefin resin; a (meth)acrylic resin; a polyester resin; a cellulose ester resin; a polycarbonate resin; Vinyl alcohol resin; vinyl acetate resin; polyarylate resin; polystyrene resin; polyether oxime resin; polyfluorene resin; polyamine resin; polyimine resin; a mixture or a copolymer or the like.

From the viewpoint of the handleability of the base film 10, the thermoplastic resin is preferably rigid at normal temperature and normal pressure (25 ° C, 101.3 kPa). The rigidity means that the glass transition temperature Tg is higher than normal temperature at normal pressure in the case of a non-crystalline polymer, and the crystallization melting point Tm is higher than normal temperature at normal pressure in the case of a crystalline polymer. If it is considered to be supplied to the stretching step (b), it is preferably a thermoplastic resin having a Tg or Tm of 100 ° C or more.

The linear polyolefin resin is preferably stretched at a high rate, and it is preferably a polypropylene resin (a polypropylene resin of a single polymer of propylene, a copolymer mainly composed of propylene, or the like) or a polyethylene resin (for example). A polyethylene resin of a single polymer of ethylene, a copolymer mainly composed of ethylene, or the like). The linear polyolefin resin is mostly in the case of crystallinity, and the polypropylene resin of the individual polymer of propylene has a crystallization melting point Tm of about 150 to 180 °C. In the case of a polyethylene resin of a single polymer of ethylene, the crystallization melting point Tm may vary depending on the density or the like, but is in the range of about 100 to 140 °C.

The heat resistance and softness of the base film 10 can be improved by using a polypropylene-based resin mainly composed of propylene and copolymerized with another monomer or a polyethylene-based resin mainly composed of ethylene and copolymerized with other kinds of monomers. Sex.

Examples of other kinds of monomers copolymerizable with propylene include ethylene and α-olefin. The α-olefin is preferably an α-olefin having 4 or more carbon atoms, 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. a branched monoolefin such as 3-methyl-1-butene, 3-methyl-1-pentene or 4-methyl-1-pentene; ethylene cyclohexane or the like. The copolymer of propylene and other monomers copolymerizable therewith may be a random copolymer or Block copolymer.

Other types of monomers copolymerizable with ethylene include, for example, an α-olefin. The α-olefin is preferably a olefin having 4 or more carbon atoms, more preferably propylene, and still more preferably an α-olefin having 4 to 10 carbon atoms, in addition to propylene.

Among the above, the polypropylene resin is preferably used: a propylene individual polymer, a propylene-ethylene random copolymer, a propylene-1-butene random copolymer, and a propylene-ethylene-1-butene random copolymer. . Further, as the polyethylene resin, an ethylene individual polymer, 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 essentially an isotactic polymer or a syndiotactic polymer. The base film composed of the propylene resin is excellent not only in handleability but also in mechanical strength in a high temperature environment.

When the linear polyolefin resin is composed of a copolymer of a main monomer and another monomer (copolymerization component), the content (copolymerization ratio) of the other monomer is preferably a small amount, and specifically, it is preferably 10% by weight or less, more preferably 8% by weight or less. When the copolymerization ratio is small, the copolymer forms a state containing a large amount of crystallized segments at normal temperature and normal pressure, and thus a rigid resin is easily formed. On the other hand, when the copolymerization ratio is too high, a liquid form is formed under normal temperature and normal pressure, and conversely, heat resistance may be lowered. The copolymerization ratio of other kinds of monomers in the copolymer, in addition to the calculation of the increase or decrease of the substance during the polymerization, can also be carried out in accordance with the "Handbook of Polymer Analysis" (issued in 1995, issued by Kiyuki Ueya Electric Co., Ltd.). The method was determined by measuring with an infrared (IR) spectrum.

Cyclic polyolefin resin is a polymerization of a cyclic olefin as a polymerization unit A general term for the resin, for example, a resin contained in JP-01-240517-A, JP-03-14882-A, JP-03-122137-A, or the like. Specific examples of the cycloolefin-based resin include a ring-opening (co)polymer of a cyclic olefin, an addition polymer of a cyclic olefin, and a copolymer of a cyclic olefin and a linear olefin such as ethylene or propylene (which is representative). It is a random copolymer), and the above-mentioned cyclic copolymers modified with unsaturated carboxylic acids and derivatives thereof, and the like. Among them, the cyclic olefin is preferably a borneol-based resin obtained by using a borneol-based monomer such as a norbornene or a polycyclic norbornene-based monomer.

Examples of the products of the cyclic polyolefin resin are "Topas" (manufactured by TOPAS ADVANCED POLYMERS GmbH, available from Japan Polyplastics Co., Ltd.), "ARTON" (manufactured by Japan JSR Corporation), and "ZEONOR" (Japan Zeon). Manufactured by the company, "ZEONEX" (made by Zeon Corporation of Japan), "APEL" (manufactured by Mitsui Chemicals, Inc.), etc., all of which are trade names.

Examples of the (meth)acrylic resin include poly(meth)acrylate such as polymethyl methacrylate, methyl methacrylate-(meth)acrylic acid copolymer, and methyl methacrylate-(methyl). Acrylate copolymer, methyl methacrylate-acrylate-(meth)acrylic acid copolymer, methyl (meth)acrylate-styrene copolymer (MS resin, etc.), alicyclic hydrocarbon group-containing polymer ( For example, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate-methacrylate methacrylate copolymer, and the like. It is preferably poly(methyl) acrylate or the like, the alkyl moiety of which is a poly(meth)acrylic acid alkyl ester having 1 to 6 carbon atoms, more preferably methyl methacrylate as a main component (50 to 100 weight). More preferably, the methyl methacrylate resin is preferably from 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 compound thereof) with a polyhydric alcohol. The polycarboxylic acid mainly uses a divalent carboxylic acid such as isophthalic acid, terephthalic acid, dimethyl terephthalate or dimethyl naphthalate. The polyol mainly uses a dihydric alcohol such as propylene glycol, butanediol, neopentyl glycol, cyclohexanedimethanol or the like. Specific examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, and polybutylene terephthalate. Trimethyl ester, triamethylene naphthalate, dimethyl dimethyl terephthalate, cyclohexane dimethyl phthalate, and the like. These mixed resins or copolymers may also be suitably used.

The cellulose ester resin is an ester of cellulose and a fatty acid. Specific examples of the cellulose ester-based resin include triacetate cellulose, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate, and examples thereof include copolymers and a part of hydroxyl groups thereof, and other substituents. Modifiers, etc. Among them, particularly preferred is cellulose triacetate. There are a variety of commercially available products of cellulose triacetate which are advantageous from the point of availability and cost. Examples of the sales of the cellulose triacetate include "FUJITAC TD80" (manufactured by Fujifilm Co., Ltd.), "FUJITAC TD80UF" (manufactured by Fujifilm Co., Ltd.), "FUJITAC TD80UZ" (manufactured by Fujifilm Co., Ltd.), " FUJITAC TD40UZ" (manufactured by Fujifilm Co., Ltd.), "KC8UX2M" (manufactured by Konica Minolta Opto Products Co., Ltd.), "KC4UY" (manufactured by Konica Minolta Opto Products Co., Ltd., Japan), etc., all of which are trade names.

The polycarbonate resin is an engineering plastic composed of a polymer that permeates a monomer unit bonded through a carbonate group, and has high impact resistance, heat resistance, and resistance. Flammable resin. At the same time, it is suitable for use in optical applications because of its high transparency. In optical applications, in order to reduce the photoelastic coefficient, there are modified polymer skeletons, such as modified polycarbonate resins, and copolymerized polycarbonates with improved wavelength dependence, which are commercially available and suitable for use. Use. Examples of polycarbonate resin-selling products include "Panlite" (Emperor Chemical Co., Ltd.), "Iupilon" (Mitsubishi Industrial Plastics Co., Ltd.), "SD Polyca" (Sumitomo Ceramics Co., Ltd.), and "Calibre" (Tao) Chemical company), etc., all of which are trade names.

The rubber component dispersed in the thermoplastic resin has a rubber-elastic resin component, and generally the rubber particles are uniformly dispersed in the thermoplastic resin. By mixing and dispersing the rubber component, the tensile strength of the substrate film and even the film can be increased. 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, it is preferably one composed of the same or similar resin as the thermoplastic resin to be used.

For example, when the thermoplastic resin is a linear polyolefin resin, the rubber component may be a copolymer of two or more monomers selected from ethylene and an α-olefin. In this case, the content (polymerization ratio) of each monomer constituting the copolymer is preferably less than 90% by weight, more preferably less than 80% by weight. When the content of one type of monomer unit is excessively high, the monomer unit is easily formed into a continuous segment and is easily crystallized, and the rubber elasticity is lost.

The rubber component composed of the copolymer of the above two or more kinds of monomers can be suitably used in various copolymers including ethylene units, and among them, ethylene units, propylene units, butene units, and octene units are preferably used. And a copolymer of one or more selected units selected from the group consisting of styrene units. The The content (polymerization ratio) of the ethylene unit 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, still more preferably 25% by weight or more and 70% by weight or less. the following. A preferred embodiment of the substrate film used in the present invention is a polypropylene resin (for example, a propylene alone polymer) as a thermoplastic resin in which a copolymer as a rubber component is dispersed, wherein the copolymer The ethylene unit is contained in the above content.

The content of the ethylene unit in the copolymer can be calculated by adding or subtracting the substance during the polymerization, and can also be borrowed according to the method described in the "Handbook of Polymer Analysis" (1995, issued by Kiyoshiya Shoten). It was determined by performing infrared (IR) spectrum measurement.

In the case of a thermoplastic resin-based (meth)acrylic resin, from the viewpoint of mutual solubility, an acrylic polymer containing rubber rubber as a rubber component is preferable. The acrylic polymer may be a polymer mainly composed of an alkyl acrylate, and a single polymer of an alkyl acrylate may be a copolymer of 50% by weight or more of an alkyl acrylate and 50% by weight or less of another monomer.

The alkyl acrylate generally uses an alkyl group having a carbon number of 4 to 8. Examples of the other monomer mentioned above include alkyl methacrylate such as methyl methacrylate and ethyl methacrylate, styrene monomers such as styrene and alkyl styrene, acrylonitrile and methyl group. Examples of the monofunctional monomer such as an unsaturated nitrile such as acrylonitrile include an unsaturated carboxylic acid ester such as (meth)acrylic acid acrylate and (meth)acrylic acid methacrylic acid ester. a polyfunctional monomer such as a dibasic acid of a dibasic acid such as dipropylene maleate or an unsaturated carboxylic acid diester of a glycol such as an alkanediol di(meth)acrylate .

The rubber component containing the acrylic polymer is preferably in the form of particles, preferably It is a particle of a multilayer structure containing a layer of an acrylic polymer. A two-layer structure having a layer of a polymer mainly composed of an alkyl methacrylate on the outer side of the layer (core) of the acrylic polymer may have an alkyl methacrylate on the inner side of the layer of the acrylic polymer. A three-layer structure of a layer (core) of a polymer in which an ester is a main component may also be used. The acrylic rubber particles having a multilayer structure can be produced, for example, by the method described in JP-55-27576-B.

The blending amount of the rubber component is preferably from 5 to 50% by weight, more preferably from 10 to 45% by weight, based on the thermoplastic resin. When the blending amount of the rubber component is too small, the effect of sufficiently improving the tensile strength tends to be insufficient, and when the blending amount of the rubber component is too large, the handleability of the base film tends to be lowered.

The method of dispersing the rubber component in the thermoplastic resin is not particularly limited, and examples thereof include a method in which a thermoplastic resin and a rubber component (rubber particles) produced separately are mixed by an plastomill or the like, and In the case of preparing a thermoplastic resin, a rubber component is prepared in the same reaction vessel to obtain a thermoplastic resin resin mixture method in which a rubber component is dispersed. The reactor mixing method is advantageous in increasing the degree of dispersion of the rubber component.

In the base film 10, any appropriate additives may be added in addition to the thermoplastic resin and the rubber component. Such an additive may, for example, be a mutual solvent which improves the dispersibility of a rubber component, an ultraviolet absorber, an antioxidant, a slip agent, a plasticizer, a mold release agent, a coloring inhibitor, a flame retardant, a nucleating agent, and an anti Chargers, pigments, and colorants. The total content of the thermoplastic resin and the rubber component in the substrate film is preferably from 50 to 100% by weight, more preferably from 50 to 99% by weight, still more preferably from 60 to 98% by weight, particularly preferably from 70 to 97% by weight. When the total content is less than 50% by weight, the thermoplastic resin may have The high transparency and the like cannot be fully expressed.

The mutual solvent may also be a low-molecular one. However, it is preferable to use a mutual solvent composed of a polymer because of the concern of bleeding or the like. Examples of the mutual solvent composed of the polymer include a block copolymer and the like, and specific examples thereof include a styrene-ethylene-butylene-styrene block copolymer.

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

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 the adhesion to the polyvinyl alcohol-based resin layer 20, corona treatment, plasma treatment, flame treatment, or the like may be applied. The adhesion is improved, or a thin layer of a primer layer, an adhesive layer, or the like is formed.

(polyvinyl alcohol resin layer)

The polyvinyl alcohol-based resin forming the polyvinyl alcohol-based resin layer 20 is, for example, a polyvinyl alcohol resin or a derivative thereof. Examples of the derivative of the polyvinyl alcohol resin include, for example, polyethylene formaldehyde and polyvinyl acetaldehyde, and examples thereof include an olefin such as ethylene or propylene, acrylic acid, methacrylic acid or crotonic acid. Those which are not saturated with carboxylic acid, unsaturated carboxylic acid alkyl ester, acrylamide or the like. Among them, a polyvinyl alcohol resin is preferably used.

The polyvinyl alcohol-based resin is preferably a completely saponified one. The degree of saponification is preferably in the range of 80.0 to 100.0 mol%, more preferably 90.0 to 99.5 mol%, still more preferably 94.0 to 99.0 mol%. If the degree of saponification is less than 80.0 mol%, the water resistance and moisture resistance will be significantly deteriorated after the polarizing laminated film is formed. Good situation. At the same time, when a polyvinyl alcohol-based resin having a degree of saponification of more than 99.5 mol% is used, the dyeing speed is remarkably slowed, so that a polarizing laminated film having sufficient polarizing properties cannot be obtained, and there is also production. It takes a few times as much time as usual.

Here, the degree of saponification is a ratio of a hydroxyl group which changes the acetic acid group contained in the polyvinyl acetate-based resin, which is contained in the polyvinyl acetate-based resin, by a saponification step, and is expressed by a unit ratio (% by mole). The value defined by the statement. That is, it can be obtained by the method specified in JIS K 6726 (1994).

Degree of saponification (% by mole) = (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 from 100 to 10,000, more preferably from 1,500 to 8,000, still more preferably from 2,000 to 5,000. The average degree of polymerization herein is a value determined in accordance with the method specified in JIS K 6726 (1994).

The above polyvinyl alcohol-based resin may be further added with an additive such as a plasticizer or a surfactant in accordance with the necessity. As the plasticizer, a polyhydric alcohol, a condensate thereof, or the like can be used, for example, glycerin, propylene glycol, triglycerol, ethylene glycol, propylene glycol, polyethylene glycol, or the like. The blending amount of the additive is not particularly limited, but is preferably 20% by weight or less of the polyvinyl alcohol-based resin.

The polyvinyl alcohol-based resin solution obtained by dissolving a polyvinyl alcohol-based resin in a good solvent is preferably applied to one side of the base film 10, and dried to evaporate the solvent to form a polyvinyl alcohol-based resin layer 20. According to this method, the thin polyvinyl alcohol-based resin layer 20 can be formed. The method of applying the polyvinyl alcohol-based resin solution to the base film 10 can be carried out by a roll coating method such as a bar coating method, a reverse coating method, a gravure coating method, or the like. A method generally selected from the methods such as a method, a screen printing coating method, a fountain coating method, an impregnation method, and a spray coating method are appropriately selected. The drying temperature is, for example, 50 to 200 ° C, preferably 60 to 150 ° C. The drying time is, for example, 2 to 20 minutes.

As described above, before the formation of the polyvinyl alcohol-based resin layer 20, a primer layer for the purpose of improving the adhesion can be formed on the surface of the base film 10 on the side where the polyvinyl alcohol-based resin layer 20 is formed. For example, a solution containing a polyvinyl alcohol-based resin and a crosslinking agent can be applied in the same manner as described above and dried to form a primer layer.

Further, the polyvinyl alcohol-based resin layer 20 may be formed by laminating a film made of a polyvinyl alcohol-based resin on the base film 10, and in this case, an adhesive may be used in the film.

The thickness of the polyvinyl alcohol-based resin layer 20 in the laminated film 100 is preferably 3 μm or more and 50 μm or less, and more preferably 5 μm or more and 45 μm or less. When it is 3 μm or less, the film is too thin after stretching, and the dyeability is remarkably deteriorated. When it exceeds 50 μm, the polarizing laminated film obtained is thickened.

(b) Extension steps

This step is a step of uniaxially stretching the laminated film 100 including the base film 10 and the polyvinyl alcohol-based resin layer 20 to obtain the stretched film 200 (refer to FIG. 2). The stretching ratio of the laminated film 100 can be appropriately selected in accordance with the desired polarizing characteristics, but is preferably more than 5 times and 17 times or less, more preferably more than 5 times and 8 times or less with respect to the original length of the laminated film 100. When the stretching ratio is 5 or less, the stretched polyvinyl alcohol-based resin layer 20' cannot be completely aligned, and as a result, the degree of polarization of the polarizer layer cannot be sufficiently improved. On the other hand, if extended When the magnification is higher than 17 times, the film is likely to be broken at the time of stretching, and at the same time, the thickness of the film is made thinner than necessary, and the workability and workability in the subsequent step are reduced. In the present invention, since the base film 10 dispersed with the rubber component as described above is used, even when the expansion ratio exceeds 5 times, the obtained stretched film 200 has high resistance to cracking in the extending direction. Therefore, according to the present invention, it is possible to provide a polarizing laminated film which exhibits high polarization characteristics while having high durability.

The uniaxial extension processing is not limited to one extension, and may be performed in multiple stages. In this case, it is preferable to carry out the stretching treatment at a stretching ratio of more than 5 times in total of all the stages of the stretching treatment.

The uniaxial stretching is preferably a longitudinal extension of the extension to the longitudinal direction of the laminated film 100 (film transport direction). Examples of the longitudinal stretching method include a roll stretching method, a compression stretching method, and a stretching method using a tenter. At the same time, the uniaxial stretching is not limited to the longitudinal stretching treatment, and may be oblique stretching or the like.

The stretching process may be either a wet stretching method or a dry stretching method, but when the dry stretching method is used, it is preferable since the temperature during stretching can be selected from a wide range.

The stretching temperature may be set in the vicinity of the glass transition temperature Tg or the crystallization melting point Tm of the substrate film, preferably in the range of [(Tg or Tm) -30 ° C] to [(Tg or Tm) + 15 ° C], more preferably [(Tg or Tm) - 25 ° C] to the range of [Tg or Tm]. If the extension temperature is lower than [(Tg or Tm) -30 °C], it will be difficult to extend the magnification of more than 5 times. If the elongation temperature exceeds [(Tg or Tm) + 15 ° C], the fluidity of the base film 10 is too large, so that it is difficult to extend. The tendency. Further, the stretching temperature is in the above range, and more preferably at 120 °C. When the stretching temperature is 120 ° C or more, it is not difficult to extend the stretching treatment at a stretching ratio of more than 5 times. Generally, the temperature adjustment of the elongation treatment is performed by the temperature adjustment of the heating furnace.

When the thickness of the laminated film 100 is in the above range, the thickness of the uniaxially stretched base film 10' in the stretched film 200 is generally from 1 to 300 μm, more preferably from 1 to 100 μm. Further, the thickness of the uniaxially stretched polyvinyl alcohol-based resin layer 20' in the stretched film 200 is preferably from 1 to 10 μm, more preferably from 2 to 8 μm. When the thickness of the expanded polyvinyl alcohol-based resin layer 20' is 1 μm or less, the dyeability is remarkably deteriorated, and when it exceeds 10 μm, the obtained polarizing laminated film is made thick.

(c) Dyeing step

This step is a step of dyeing the polyvinyl alcohol-based resin layer 20' of the stretched film 200 with a dichroic dye to obtain a dyed film 300 (refer to Fig. 3). Examples of the dichroic dye include iodine and an organic dye. For the organic dye, for example, red dye BR, red dye LR, red dye R, pink dye LB, ruby dye BL, red wine dye GS, sky blue dye LG, lemon yellow dye, blue dye BR, blue Dye 2R, Navy Blue Dye RY, Green Dye LG, Purple Dye LB, Purple Dye B, Black Dye H, Black Dye B, Black Dye GSP, Yellow Dye 3G, Yellow Dye R, Orange Dye LR, Orange Dye 3R, Gorilla Red dye GL, scarlet dye KGL, Congo red dye, bright purple dye BK, ultra blue dye G (suprablue G), ultra blue dye GL, super orange dye GL, direct blue dye, direct light orange dye S (direct fast orange S), light fast black dye Wait. These dichroic substances may be used alone or in combination of two or more.

For example, the entire stretch film 200 can be immersed in a solution (dye solution) containing the above-described dichroic dye, whereby the dyeing step can be carried out. As the dyeing solution, a solution in which the above dichroic dye is dissolved in a solvent can be used. The solvent of the dyeing solution can generally be water, but an organic solvent which is miscible with water can be further added. The concentration of the dichroic dye is preferably from 0.01 to 10% by weight, more preferably from 0.02 to 7% by weight, particularly preferably from 0.025 to 5% by weight.

Since the dyeing efficiency can be further improved by using iodine in the dichroic dye, it is preferred to add the iodide to the dyeing solution containing iodine. Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, cesium iodide, calcium iodide, tin iodide, and titanium iodide. The concentration of the iodide in the dyeing solution is preferably from 0.01 to 20% by weight. Among the iodides, potassium iodide is preferably added. 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, and particularly preferably in the range of 1:7 to 1:70. The scope.

The time during which the stretched film 200 is immersed in the dyeing solution is not particularly limited, and is preferably in the range of 15 seconds to 15 minutes, more preferably in the range of 30 seconds to 3 minutes. Further, the temperature of the dyeing solution is preferably in the range of 10 to 60 ° C, more preferably in the range of 20 to 40 ° C.

Further, the dyeing step may be performed before or at the same time as the stretching step, but the dichroic dye adsorbed on the polyvinyl alcohol-based resin layer may be favorably aligned, and it is preferred to carry out the stretching step after the laminated film 100 is subjected to the stretching step.

(d) Cross-linking step

In this step, the polyvinyl alcohol-based resin layer 30 of the dyed film 300 obtained by dyeing the dichroic dye is subjected to a crosslinking treatment to crosslink the polyvinyl alcohol-based resin, whereby the polyvinyl alcohol-based resin layer can be used. The step of forming the polarizer layer 40 and obtaining the crosslinked film 400 (refer to Fig. 4). The crosslinking step can be carried out, for example, by immersing the dyed film 300 in a solution containing a crosslinking agent (crosslinking solution). As the crosslinking agent, those known in the art can be used. For example, a boron compound such as boric acid or borax, and glyoxal or glutaraldehyde. One type of these species may be used alone, or two or more types may be used in combination.

As the crosslinking solution, a solution in which a crosslinking agent is dissolved in a solvent can be used. The solvent may be used, for example, water, but may contain an organic solvent which is miscible with water. 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.

The cross-linking solution can be added with iodide. The polarization characteristics inside the surface of the polarizer layer 40 can be made more uniform by the addition of iodide. Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, cesium iodide, calcium iodide, tin iodide, and titanium iodide. The concentration of the iodide is preferably from 0.05 to 15% by weight, more preferably from 0.5 to 8% by weight.

The time during which the dyed film 300 is immersed in the crosslinking solution is preferably from 15 seconds to 20 minutes, more preferably from 30 seconds to 15 minutes. Further, the temperature of the crosslinking solution is preferably in the range of 10 to 90 °C.

Further, the crosslinking step and the dyeing step can be carried out simultaneously by blending the crosslinking agent in the dyeing solution. In addition, the crosslinking step and the stretching step can also be carried out simultaneously.

(e) drying step

The obtained crosslinked film 400 is generally dried after being washed. Thereby, a polarizing laminated film can be obtained (refer to Fig. 5). The washing can be carried out by immersing the crosslinked film 400 in pure water such as ion-exchanged water or distilled water. The water washing temperature is usually from 3 to 50 ° C, preferably from 4 to 20 ° C. The immersion time is generally from 2 to 300 seconds, preferably from 5 to 240 seconds. The washing may be carried out by washing with an iodide solution and washing with water, and a solution of a liquid alcohol blended with methanol, ethanol, isopropanol, butanol or propanol may be suitably used.

The drying method may be any suitable method (such as natural drying, air drying, and heat drying). For example, the drying temperature during heat drying is generally from 20 to 95 ° C, and the drying time is usually from about 1 to 15 minutes.

The polarizing laminated film system includes a polarizer layer 40 composed of a polyvinyl alcohol-based resin layer that adsorbs a dichroic dye, and can be used as a polarizing plate itself. According to the method of the present invention, the thickness of the polarizer layer 40 can be made 10 μm or less, so that a thin polarizing laminated film can be obtained. Further, the polarizing laminated film of the present invention is excellent in both polarizing performance and durability.

<Method of Manufacturing Polarizing Plate with Protective Film>

The above polarizing laminated film is also useful as an intermediate for producing a polarizing plate attached to a protective film, and by using the polarizing laminated film, the polarizing plate with the protective film can be efficiently manufactured and produced. good. An example of a polarizing plate with a protective film can be as shown in Fig. 6. The polarizing plate 600 with a protective film shown in the figure has a protective film 50 on the side opposite to the surface on which the layered substrate film 10' is laminated in the polarizer layer 40. In the example of Fig. 6, the base film 10' is peeled off, and the polarizing plate with the protective film may have the base film 10'.

Using the above polarizing laminate film and by the method comprising the following steps A polarizing plate with a protective film can be produced.

(A) a step of bonding the protective film 50 to the surface of the polarizer layer 40 of the polarizing laminated film 500 on the side opposite to the side of the base film 10', and (B) a step of peeling off the base film 10'. Further, the step (B) is a step as described above.

The protective film 50 whose thermoplastic resin constituting the base film can be composed of the same resin as the above-mentioned resin. The protective film 50 may be imparted to the phase difference by uniaxial stretching or biaxial stretching.

The protective film 50 is preferably thinner, but if it is too thin, the strength is lowered and the workability is deteriorated. On the other hand, when it is too thick, there is a problem that the transparency is reduced or the curing time required after lamination is lengthened. Therefore, the thickness of the protective film 50 is preferably 80 μm or less, more preferably 5 to 60 μm. Moreover, 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 from the viewpoint of the thickness reduction of the polarizing plate with a protective film.

On the surface of the protective film 50 opposite to the polarizer layer 40, an optical layer such as a cured film layer, an anti-glare layer, a light-diffusing layer, an anti-reflection layer or the like may be formed.

The bonding of the polarizer layer 40 and the protective film 50 can be carried out using an adhesive or an adhesive. The subsequent agent may, for example, be a water-based adhesive such as a polyvinyl alcohol-based resin aqueous solution or an aqueous two-component urethane-based emulsion adhesive. When the cellulose ester-based resin film hydrophilized by a saponification treatment or the like is used as the protective film 50, a polyvinyl alcohol-based resin aqueous solution is suitably used as the adhesive. In the polyvinyl alcohol-based resin used as an adhesive, in addition to the single vinyl acetate The polyvinyl acetate of the sole polymer is subjected to a saponification treatment of a vinyl alcohol homopolymer, and a vinyl alcohol copolymer obtained by subjecting a copolymer of vinyl acetate and another monomer copolymerizable therewith to a saponification treatment. And a modified polyvinyl alcohol-based polymer obtained by modifying a part of the hydroxyl groups. Additives such as a polyvalent aldehyde, a water-soluble epoxy compound, a melamine-based compound, a zirconia compound, and a zinc compound may be added to the aqueous binder.

The method of bonding the polarizer layer 40 and the protective film 50 with a water-based adhesive is not particularly limited, and examples thereof include a casting method, a bar coating method, a gravure coating method, and a comma coating method. , a doctor blade coating method, a die coating method, an impregnation coating method, a spray method, or the like, and an adhesive is uniformly applied to the surface of the polarizer layer 40 and/or the protective film 50, and the other film is superposed on the coated surface to be a roller or the like. Make it fit and dry. The casting method is a method in which the polarizer layer 40 or the protective film 50 of the object to be coated is moved in an oblique direction slightly in the vertical direction, in the horizontal direction, or in the oblique direction therebetween, and an adhesive is applied to the surface thereof to diffuse.

After the polarizer layer 40 is bonded to the protective film 50, the laminated film is dried in order to remove water contained in the aqueous adhesive. The drying temperature is preferably from 30 to 90 °C. If it is less than 30 ° C, the polarizer layer 40 and the protective film 50 tend to be easily peeled off. Further, when the temperature is 90 ° C or more, the polarizing performance is deteriorated due to heat. The drying time may be from 10 to 1,000 seconds, and particularly preferably from 60 to 750, more preferably from 150 to 600 seconds from the viewpoint of productivity. After drying, it may be cured at room temperature or slightly higher than room temperature, for example, at a temperature of about 20 to 45 ° C for about 12 to 600 hours. The curing temperature is generally set to be lower than the temperature used for drying.

A photocurable adhesive can also be used as the adhesive for bonding the polarizer layer 40 and the protective film 50. The photocurable adhesive may, for example, be a mixture of a photocurable epoxy resin and a photocationic polymerization initiator.

When a photocurable adhesive is used, the polarizer layer 40 and the protective film 50 are bonded together in the same manner as described above, and then cured by an active energy ray to cure the photocurable adhesive. The light source of the active energy ray is not particularly limited, but is preferably an active energy ray having a light-emitting distribution at a wavelength of 400 nm or less, and specifically, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, Chemical lamps, black lamps, microwave excited mercury lamps, metal halide lamps, and the like.

The light irradiation intensity of the photocurable adhesive can be appropriately determined depending on the composition of the photocurable adhesive, and is not particularly limited, but it is preferably 0.1 to 6000 mW in the wavelength range effective for activating the polymerization initiator. /cm ² . When the irradiation intensity is 0.1 mW/cm ² or more, the reaction time is not excessively long, and when the irradiation intensity is 6,000 mW/cm ² or less, yellowing of the epoxy resin occurs due to heat generation of the radiant heat of the light source and hardening of the photocurable adhesive. There are fewer concerns about degradation of the polarizer layer. The light irradiation time of the photocurable adhesive agent is not particularly limited as long as it can be suitably used in accordance with the cured photocurable adhesive, but it is preferable that the integrated light amount represented by the product of the irradiation intensity and the irradiation time is 10 to Set in the mode of 10000mJ/cm ² . When the total amount of light of the photocurable adhesive is 10 mJ/cm ² or more, the amount of active species produced by the polymerization initiator can be sufficiently increased, and the curing reaction can be surely performed. When the amount is 10000 mJ/cm ² or less, The irradiation time is not too long and good productivity can be maintained.

Further, in the bonding of the polarizer layer 40 and the protective film 50, in order to improve the adhesion, the plasma treatment, the corona treatment, and the ultraviolet irradiation may be performed on the surface of the polarizer layer 40 and/or the protective film 50 as needed. Surface treatment such as treatment, flame treatment, saponification treatment, and the like. The saponification treatment may be carried out by immersing in an aqueous alkali solution such as sodium hydroxide or potassium hydroxide.

On the other hand, the adhesive used for bonding the polarizer layer 40 and the protective film 50 is generally an acrylic resin, a styrene resin, a polyoxymethylene resin or the like as a base polymer, and an isocyanate compound is added thereto. A composition of a crosslinking agent such as an epoxy compound or an aziridine compound. The composite may contain fine particles and serve as an adhesive layer for exhibiting light scattering properties.

The thickness of the adhesive layer is preferably from 1 to 40 μm, but it is preferably a thin layer, more preferably from 3 to 25 μm, insofar as the workability, durability, and the like are not impaired. If the thickness of the adhesive layer is less than 1 μm, the adhesiveness is lowered. If it exceeds 40 μm, the adhesive may leak.

The method of bonding the polarizer layer 40 and the protective film 50 with an adhesive is not particularly limited, and a solution containing the components of the base polymer may be applied to the surface of the protective film or the surface of the polarizer layer ( After the adhesive composition is dried to form an adhesive layer, the polarizer layer 40 is bonded to the protective film 50, and an adhesive layer may be formed on the separation layer (release film), and then transferred to a protective film. The polarizer layer 40 is bonded to the protective film 50 on the surface or on the surface of the polarizer layer.

At the same time, in order to improve the adhesion, it is necessary to perform surface treatment such as corona treatment on the bonding surface of the polarizer layer 40 and/or the protective film 50 or on one or both sides of the adhesive layer.

The above step (B) is a step of peeling off the base film 10' by the laminate comprising the base film 10'/polarizer layer 40/protective film 50 obtained in the step (A). The base film 10' may be directly peeled off immediately after the protective film 50 is bonded, or may be temporarily rolled up into a roll shape after the protective film 50 is bonded, and then the substrate film may be circumscribed in the subsequent step. 10' peel off.

(Example)

Hereinafter, the present invention will be specifically described by way of Examples, but the present invention is not limited by the Examples.

[Production of polarizing laminated film] <Example 1>

(1) Fabrication of substrate film

The thermoplastic resin and the rubber component were sequentially adjusted in the same reactor by a reactor mixture method. Specifically, a propylene monomer as a first step is fed in a gas phase using a Ziegler-Natta catalyst and a propylene-individual polymer of a thermoplastic resin is produced. After the propylene monomer feed is terminated and the reaction is stopped, the ethylene monomer and the propylene monomer as the second step are directly fed in the gas phase in the reaction vessel to produce an ethylene-propylene copolymer of a rubber component. A propylene individual polymer obtained by dispersing an ethylene-propylene copolymer of a rubber component in the form of particles. The content of the ethylene unit in the copolymer was 35 wt% as calculated from the increase or decrease of the substance at the time of polymerization. In addition, the content of the ethylene unit in the total resin (total of the thermoplastic resin and the rubber component) can be obtained by the method described in the "Handbook of Polymers" (published by Kiyoshiya Shoten, 1995) on page 616. When calculating the content of the ethylene-propylene copolymer in the entire resin, the result is 29% by weight, (that is, the content of the ethylene-propylene copolymer is 40.8% by weight of the thermoplastic resin).

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

(2) Formation of the bottom layer

First, polyvinyl alcohol powder ("Z-200" manufactured by Nippon Synthetic Chemical Industry Co., Ltd., average polymerization degree 1100, average saponification degree 99.5%) was dissolved in hot water at 95 ° C to prepare a polyvinyl alcohol having a concentration of 3% by weight. Aqueous solution. Then, 5 parts by weight of a crosslinking agent ("SUMIREZ Resin 650" manufactured by Sumitomo Chemical Co., Ltd.) was mixed with 6 parts by weight of the polyvinyl alcohol powder in the obtained aqueous solution. The resulting mixed aqueous solution was applied to a corona-treated surface of the substrate film subjected to corona treatment by a micro gravure coater, and then dried at 80 ° C for 10 minutes to form a bottom layer having a thickness of 0.2 μm.

(3) Formation of a polyvinyl alcohol-based resin layer

First, polyvinyl alcohol powder ("PVA124" manufactured by Kuraray Co., Ltd., average polymerization degree 2400, average saponification degree: 98.0 to 99.0 mol%) was dissolved in hot water at 95 ° C to prepare a concentration of 8 wt%. Aqueous vinyl alcohol solution. The obtained aqueous solution was applied to the above-mentioned underlayer by a nozzle coater, and dried at 80 ° C for 2 minutes, at 70 ° C for 2 minutes, and then at 60 ° C for 4 minutes, thereby preparing a substrate film. A laminate film of a polyvinyl alcohol-based resin layer is laminated on the bottom layer. The thickness of the polyvinyl alcohol-based resin layer was 9.8 μm.

(4) Production of stretch film

The laminated film was stretched uniaxially at a stretching temperature of 160 ° C by 5.8 times from the longitudinal axis of the free end to obtain an expanded film. The thickness of the obtained stretched film was 28.5 μm, and the thickness of the polyvinyl alcohol-based resin layer was 4.2 μm.

(5) Production of polarizing laminated film

After immersing the above-mentioned stretched film in a warm bath of 60 ° C for 60 seconds, it was immersed in a 30 ° C dyeing solution containing an aqueous solution of iodine and potassium iodide for about 150 seconds to dye the polyvinyl alcohol-based resin layer, and then 10 ° C. Rinse excess iodine solution with pure water. Next, it was immersed in a 76 ° C crosslinking solution containing an aqueous solution of boric acid and potassium iodide for 600 seconds. Thereafter, the film was further washed with pure water of 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, defects such as film breakage after stretching do not occur, and thus a polarizing laminated film can be produced stably.

<Example 2>

In addition to the ethylene monomer and the 1-butene monomer, the ethylene component and the 1-butene monomer are fed in the second step of the "(1) production of the base film" of the first embodiment, and the rubber component is prepared as an ethylene-butene copolymer. A substrate film having a thickness of 100 μm was produced in the same manner as in Example 1. The content of the ethylene unit in the copolymer was 35% by weight. The content of the ethylene unit in the entire resin was 30% by weight (that is, the content of the ethylene-propylene copolymer was 42.9% by weight of the thermoplastic resin).

Using the thus obtained base film, 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, defects such as film breakage after stretching do not occur, and a polarizing laminated film can be produced stably.

<Comparative Example 1>

The same operation as in Example 1 was carried out except that a base film (no rubber component) having a thickness of 100 μm was formed using propylene alone polymer (Sumitomo Noblen FLX80E4 manufactured by Sumitomo Chemical Co., Ltd., melting point Tm = 163 ° C). Make a laminate film. Thereafter, the free end longitudinal axis uniaxial stretching treatment was carried out under the same conditions as in Example 1 to obtain an expanded film having a thickness of 30.1 μm. The thickness of the polyvinyl alcohol-based resin layer in the obtained stretched film was 4.5 μm.

<Comparative Example 2>

A substrate film having a thickness of 100 μm (without rubber) using 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 A laminate film was produced in the same manner as in Example 1 except for the component. Thereafter, the free end longitudinal axis uniaxial stretching treatment was carried out under the same conditions as in Example 1 to obtain an expanded film having a thickness of 30.1 μm. The thickness of the polyvinyl alcohol-based resin layer in the obtained stretched film was 4.5 μm.

(Measurement of stretch film tensile strength)

The tensile strength of the stretched film obtained in the above Examples and Comparative Examples was measured by the following method. First, the slit is cut in parallel with the extending direction by the blade at the center of the short edge portion of the stretched film (the center in the width direction of the film). Next, using a universal testing machine ("Autograph AG-I" manufactured by Shimadzu Corporation, Japan), the stretched film was stretched from the base of the slit, and the tensile strength at this time was measured by the same apparatus. The speed at which the film was stretched was 300 mm/min. The tensile strength at each tensile distance (ie, the distance from the base point of the slit) can be measured by the operation of the measurement, but when the tensile strength is measured using a tensile tester, When the stretching distance is reached to a certain extent until the tensile angle of the film is stabilized, the tensile strength is much higher. Therefore, in this measurement, the portion was excluded, and the average value of the tensile strength in the range of the tensile strength stability was determined, and this was taken as the tensile strength. The results are shown in Table 1.

As shown in Table 1, in the stretched films of Examples 1 and 2, compared with Comparative Examples 1 and 2, it was confirmed that the film was highly resistant to cracking in the relative extension direction.

[Production of polarizing plate with protective film] <Example 3>

Using the polarizing laminate films obtained in Examples 1 and 2, a polarizing plate with a protective film was produced in the following order. Polyvinyl alcohol powder ("KL-318" manufactured by Kuraray Co., Ltd., Japan, average degree of polymerization 1800) was dissolved in hot water at 95 ° C to prepare a polyvinyl alcohol aqueous solution having a concentration of 3% by weight. Then, the crosslinking agent ("SUMIREZ Resin 650" manufactured by Sumitomo Chemical Co., Ltd.) was mixed with 1 part by weight of the polyvinyl alcohol powder in the obtained aqueous solution to obtain an adhesive solution.

Next, it is coated on the polyvinyl alcohol-based resin layer of the polarizing laminated film. After the adhesive solution is applied to a protective film made of cellulose triacetate (TAC) ("KC4UY" manufactured by Konica Minolta Opto Products Co., Ltd., Japan), a protective film/adhesive layer/polarizer is obtained. A polarizing plate composed of 5 layers of a layer/underlayer/substrate film. The base film was peeled off from the obtained polarizing plate, and a polarizing plate composed of four layers of a protective film/adhesive layer/polarizer layer/underlayer was produced. The base film can be easily peeled off.

10‧‧‧Base film

10'‧‧‧Extended base film

20‧‧‧Polyvinyl alcohol resin layer

20'‧‧‧Extended polyvinyl alcohol resin layer

30‧‧‧Dichromatic pigment dyed polyvinyl alcohol resin layer

40‧‧‧ polarizer layer

50‧‧‧Protective film

100‧‧‧ laminated film

200‧‧‧Extended film

300‧‧‧Stained film

400‧‧‧crosslinked film

500‧‧‧Polarized laminated film

600‧‧‧Polarizer with protective film

Fig. 1 is a schematic cross-sectional view showing an example of a laminated film obtained in a lamination step.

Fig. 2 is a schematic cross-sectional view showing an example of the stretched film obtained in the stretching step.

Fig. 3 is a schematic cross-sectional view showing an example of a dyed film obtained in the dyeing step.

Fig. 4 is a schematic cross-sectional view showing an example of a crosslinked film obtained in the crosslinking step.

Fig. 5 is a schematic cross-sectional view showing an example of a polarizing laminated film.

Fig. 6 is a schematic cross-sectional view showing an example of a polarizing plate with a protective film.

10'‧‧‧Extended base film

40‧‧‧ polarizer layer

500‧‧‧Polarized laminated film

Claims (7)

A method for producing a polarizing laminate film comprising: a base film obtained by dispersing a rubber component in a thermoplastic resin; and a polarizer layer laminated on one side of the base film, the production method The step of forming a polyvinyl alcohol-based resin layer on one side of a base film formed by dispersing a rubber component in a thermoplastic resin to obtain a laminated film; and extending the laminated film to a uniaxial direction to obtain an expanded film; a step of dyeing the polyvinyl alcohol-based resin layer of the stretched film with a dichroic dye to obtain a dyed film; and immersing the polyvinyl alcohol-based resin layer of the dyed film in a solution containing a crosslinking agent to cause the aforementioned A step of crosslinking a polyvinyl alcohol-based resin to form a polarizer layer from the polyvinyl alcohol-based resin layer to obtain a crosslinked film, and drying the crosslinked film. The method for producing a polarizing laminate film according to claim 1, wherein the thermoplastic resin is a polypropylene resin. The method for producing a polarizing laminate film according to claim 1, wherein the thermoplastic resin is a propylene individual polymer. The method for producing a polarizing laminate film according to any one of claims 1 to 3, wherein the rubber component is a copolymer containing an ethylene unit. The manufacturer of the polarizing laminated film described in claim 4 of the patent application scope The rubber component is a copolymer containing one or more selected from the group consisting of an ethylene unit, a propylene unit, a butene unit, an octene unit, and a styrene unit. The method for producing a polarizing laminate film according to the fourth aspect of the invention, wherein the content of the ethylene unit in the copolymer is more than 10% by weight and less than 90% by weight. A polarizing laminate film comprising a base material 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 side of the base film.