WO2014136984A1 - 偏光性積層フィルムの製造方法および偏光板の製造方法 - Google Patents

偏光性積層フィルムの製造方法および偏光板の製造方法 Download PDF

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WO2014136984A1
WO2014136984A1 PCT/JP2014/056383 JP2014056383W WO2014136984A1 WO 2014136984 A1 WO2014136984 A1 WO 2014136984A1 JP 2014056383 W JP2014056383 W JP 2014056383W WO 2014136984 A1 WO2014136984 A1 WO 2014136984A1
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film
laminated film
heating zone
polyvinyl alcohol
polarizing
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PCT/JP2014/056383
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English (en)
French (fr)
Japanese (ja)
Inventor
河村　真一
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住友化学株式会社
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Priority to KR1020157025487A priority Critical patent/KR20150125962A/ko
Publication of WO2014136984A1 publication Critical patent/WO2014136984A1/ja

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B29C55/04—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique
    • B29C55/06—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique parallel with the direction of feed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B29C55/023—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets using multilayered plates or sheets
    • B29C55/026—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets using multilayered plates or sheets of preformed plates or sheets coated with a solution, a dispersion or a melt of thermoplastic material

Definitions

  • the present invention relates to a method for producing a polarizing laminated film and a method for producing a polarizing plate.
  • the polarizing plate is widely used as a polarized light supplying element and a polarized light detecting element in a liquid crystal display device.
  • a polarizing plate a polarizing film made of a polyvinyl alcohol resin and a protective film made of triacetyl cellulose or the like bonded to an adhesive is used.
  • a polarizing film has been produced by stretching and dyeing a polyvinyl alcohol-based resin film (usually about 75 ⁇ m thick), and the thickness of the film after stretching is usually about 30 ⁇ m. Thinning beyond this has been difficult due to productivity problems such as the film during stretching being easily broken.
  • the film thickness can be improved as the stretching ratio of the laminated film is increased.
  • the draw ratio is high to some extent, if the neck-in ratio at the time of drawing is low, the orientation of the polymer chain of the polyvinyl alcohol resin becomes insufficient, and the obtained polarizer layer has sufficient polarization performance. It may not be granted. If the draw ratio is extremely increased in order to increase the orientation of the polymer chain, the film becomes brittle and the mechanical strength decreases. Moreover, it can be difficult in terms of the stretching apparatus to increase the stretching ratio extremely (for example, the stretching apparatus has insufficient torque to increase the stretching ratio extremely).
  • This invention is made
  • the objective is after coating the coating liquid containing a polyvinyl alcohol-type resin on a base film, forming a polyvinyl alcohol-type resin layer, and obtaining a laminated film
  • the method for producing a polarizing laminated film or polarizing plate by making the polyvinyl alcohol resin layer into a polarizer layer by stretching and dyeing the laminated film, the film is laminated at a high neck-in rate without excessively increasing the draw ratio.
  • An object of the present invention is to provide a method capable of stably producing a polarizing laminated film or a polarizing plate which can perform longitudinal uniaxial stretching of a film and thus has good polarizing performance.
  • the present invention includes the following. ⁇ 1> A resin layer forming step of forming a polyvinyl alcohol resin layer by applying a coating liquid containing a polyvinyl alcohol resin on at least one surface of the base film and then drying to form a laminated film.
  • a stretching step of stretching the laminated film to obtain a stretched film A dyeing step of obtaining a polarizing laminated film by dyeing a polyvinyl alcohol-based resin layer of the stretched film with a dichroic dye to form a polarizer layer; With In the stretching step, the laminated film is passed in the order of the first nip roll, the plurality of heating zones, and the second nip roll, and longitudinal uniaxial stretching is performed by a difference in peripheral speed between the first nip roll and the second nip roll, Among the plurality of heating zones, when the heating zone through which the laminated film first passes is the first heating zone and the heating zone having the highest atmospheric temperature in the zone is the second heating zone, the atmosphere in the second heating zone The manufacturing method of the polarizing laminated film whose temperature is 10 degreeC or more higher than the atmospheric temperature in a 1st heating zone.
  • ⁇ 2> The manufacturing method according to ⁇ 1>, wherein the first heating zone is a heating zone having the lowest atmospheric temperature in the zone.
  • ⁇ 3> The manufacturing method according to ⁇ 1> or ⁇ 2>, wherein the second heating zone is a heating zone through which the laminated film passes last.
  • the plurality of heating zones include three or more heating zones,
  • the second heating zone is a heating zone through which the laminated film finally passes,
  • the manufacturing method according to ⁇ 2> wherein among the three or more heating zones, a heating zone closer to the second nip roll has a higher atmospheric temperature.
  • ⁇ 5> The manufacturing method according to any one of ⁇ 1> to ⁇ 4>, wherein the laminated film is stretched at a stretch ratio of more than 5 times.
  • ⁇ 6> The method according to any one of ⁇ 1> to ⁇ 5>, wherein the thickness of the polyvinyl alcohol resin layer of the laminated film is 3 to 30 ⁇ m.
  • ⁇ 7> The method for producing a polarizing laminated film according to any one of ⁇ 1> to ⁇ 6>, wherein the base film is made of a polypropylene resin.
  • ⁇ 8> a step of preparing a polarizing laminate film obtained by the production method according to any one of ⁇ 1> to ⁇ 7>; A step of bonding a protective film on the polarizer layer of the polarizing laminate film to obtain a bonding film; A step of peeling the base film from the bonding film; The manufacturing method of a polarizing plate provided with.
  • the method of the present invention it is possible to perform longitudinal uniaxial stretching of a laminated film with a high neck-in ratio without excessively increasing the draw ratio, so that a polarizing laminated film or a polarizing plate having good polarization performance can be stably produced. Can be manufactured.
  • FIG. 1 is a flowchart showing a preferred embodiment of a method for producing a polarizing laminate film and a method for producing a polarizing plate according to the present invention.
  • FIG. 2 is a side view schematically showing one embodiment of the stretching step.
  • FIG. 3 is a side view schematically showing another embodiment of the stretching step.
  • FIG. 1 is a flowchart showing a preferred embodiment of a method for producing a polarizing laminate film and a method for producing a polarizing plate according to the present invention.
  • the manufacturing method of the light-polarizing laminated film of this embodiment includes the following steps [1] to [3] in this order.
  • Resin layer forming step S10 in which a coating liquid containing a polyvinyl alcohol resin is applied to at least one surface of a base film, and then dried to form a polyvinyl alcohol resin layer to obtain a laminated film.
  • Stretching step S20 that stretches the laminated film to obtain a stretched film.
  • the polarizing plate is bonded to a protective film on the polarizer layer of the polarizing laminate film obtained by carrying out the dyeing step S30 (bonding step S40). Then, it can obtain by peeling and removing a base film from a bonding film (peeling process S50).
  • Resin layer forming step S10 This step is a step of obtaining a laminated film by forming a polyvinyl alcohol-based resin layer on at least one surface of the base film.
  • This polyvinyl alcohol-based resin layer is a layer that becomes a polarizer layer through the stretching step S20 and the dyeing step S30.
  • a polyvinyl alcohol-type resin layer can be formed by applying the coating liquid containing a polyvinyl alcohol-type resin to the single side
  • resin layer formation process S10 is continuously performed, unwinding a base film from the film roll of a elongate base film, and conveying this. Film conveyance can be performed using a guide roll or the like.
  • the base film can be composed of a thermoplastic resin, and among them, it is preferably composed of a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, stretchability and the like.
  • thermoplastic resins include, for example, polyolefin resins such as chain polyolefin resins and cyclic polyolefin resins (norbornene resins, etc.); polyester resins; (meth) acrylic resins; cellulose triacetate, Cellulose ester resins such as cellulose diacetate; Polycarbonate resins; Polyvinyl alcohol resins; Polyvinyl acetate resins; Polyarylate resins; Polystyrene resins; Polyethersulfone resins; Polysulfone resins; Polyamide resins; Resin, and mixtures and copolymers thereof.
  • the base film may have a single-layer structure composed of one resin layer composed of one or two or more thermoplastic resins, or a plurality of resin layers composed of one or two or more thermoplastic resins are laminated. It may be a multilayer structure.
  • Examples of the chain polyolefin-based resin include homopolymers of chain olefins such as polyethylene resins and polypropylene resins, and copolymers composed of two or more chain olefins.
  • a base film made of a chain polyolefin-based resin is preferable in that it is easily stretched stably at a high magnification.
  • the base film is composed mainly of polypropylene resin (polypropylene resin which is a homopolymer of propylene or a copolymer mainly composed of propylene), polyethylene resin (polyethylene resin which is a homopolymer of ethylene or ethylene). It is more preferable to consist of a copolymer).
  • the copolymer mainly composed of propylene which is one example suitably used as a thermoplastic resin constituting the base film, is a copolymer of propylene and another monomer copolymerizable therewith.
  • Examples of other monomers copolymerizable with propylene include ethylene and ⁇ -olefin.
  • ⁇ -olefin an ⁇ -olefin having 4 or more carbon atoms is preferably used, and more preferably an ⁇ -olefin having 4 to 10 carbon atoms.
  • Specific examples of the ⁇ -olefin having 4 to 10 carbon atoms include, for example, linear monoolefins such as 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene and 1-decene; 3 -Branched monoolefins such as methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene; and vinylcyclohexane.
  • the copolymer of propylene and other monomers copolymerizable therewith may be a random copolymer or a block copolymer.
  • the content of the other monomer in the copolymer is, for example, 0.1 to 20% by weight, and preferably 0.5 to 10% by weight.
  • the content of other monomers in the copolymer can be determined by measuring infrared (IR) spectrum according to the method described on page 616 of "Polymer Analysis Handbook" (1995, published by Kinokuniya Shoten). Can be sought.
  • polypropylene resin a propylene homopolymer, a propylene-ethylene random copolymer, a propylene-1-butene random copolymer or a propylene-ethylene-1-butene random copolymer is preferably used.
  • the stereoregularity of the polypropylene resin is preferably substantially isotactic or syndiotactic.
  • a base film made of a polypropylene-based resin having substantially isotactic or syndiotactic stereoregularity has relatively good handleability and excellent mechanical strength in a high temperature environment.
  • the base film may be composed of one type of chain polyolefin-based resin, may be composed of a mixture of two or more types of chain polyolefin-based resins, or may be composed of two or more types of chain polyolefin-based resins. You may be comprised from the copolymer of resin.
  • the cyclic polyolefin resin is a general term for resins that are polymerized using a cyclic olefin as a polymerization unit, and is described, for example, in JP-A-1-240517, JP-A-3-14882, JP-A-3-122137, and the like. Resin.
  • cyclic polyolefin resins include ring-opening (co) polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers of cyclic olefins and chain olefins such as ethylene and propylene (typically Are random copolymers), graft polymers obtained by modifying them with unsaturated carboxylic acids or derivatives thereof, and hydrides thereof.
  • norbornene resins using norbornene monomers such as norbornene and polycyclic norbornene monomers as cyclic olefins are preferably used.
  • cyclic polyolefin resins Various products are commercially available for cyclic polyolefin resins.
  • Examples of commercially available products of cyclic polyolefin resins are trade names, “Topas” (TOPAS ADVANCED POLYMERS GmbH, available from Polyplastics), “Arton” (manufactured by JSR Corporation), Includes “ZEONOR” (manufactured by Nippon Zeon Co., Ltd.), “ZEONEX” (manufactured by Nippon Zeon Co., Ltd.), and “Apel” (manufactured by Mitsui Chemicals, Inc.).
  • film names such as “ESCINA” (manufactured by Sekisui Chemical Co., Ltd.), “SCA40” (manufactured by Sekisui Chemical Co., Ltd.), “ZEONOR FILM” (manufactured by Nippon Zeon Co., Ltd.), etc. You may use the commercial item of the made cyclic polyolefin resin film as a base film.
  • the base film may be composed of one kind of cyclic polyolefin-based resin, may be composed of a mixture of two or more kinds of cyclic polyolefin-based resins, or may be composed of two or more kinds of cyclic polyolefin-based resins. It may be composed of a polymer.
  • the polyester-based resin is a resin having an ester bond, and is generally made of a polycondensate of a polyvalent carboxylic acid or a derivative thereof and a polyhydric alcohol.
  • a polyvalent carboxylic acid or a derivative thereof a divalent dicarboxylic acid or a derivative thereof can be used, and examples thereof include terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalenedicarboxylate.
  • a divalent diol can be used, and examples thereof include ethylene glycol, propanediol, butanediol, neopentyl glycol, and cyclohexanedimethanol.
  • polyester resin is polyethylene terephthalate, which is a polycondensate of terephthalic acid and ethylene glycol.
  • Polyethylene terephthalate is a crystalline resin, but the one in a state before crystallization treatment is more easily subjected to treatment such as stretching. If necessary, it can be crystallized during stretching or by heat treatment after stretching.
  • a copolymerized polyester having a crystallinity lowered (or made amorphous) by further copolymerizing another monomer with a polyethylene terephthalate skeleton is also preferably used.
  • examples of such resins include those obtained by copolymerizing cyclohexanedimethanol and isophthalic acid. Since these resins are also excellent in stretchability, they can be suitably used.
  • polyester resins other than polyethylene terephthalate and copolymers thereof include, for example, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethyl terephthalate, Examples include polycyclohexanedimethyl naphthalate.
  • the base film may be composed of one kind of polyester resin, may be composed of a mixture of two or more kinds of polyester resins, or may be composed of a copolymer of two or more kinds of polyester resins. It may be configured.
  • the (meth) acrylic resin is a resin containing a compound having a (meth) acryloyl group as a main constituent monomer.
  • Specific examples of (meth) acrylic resins include, for example, poly (meth) acrylic acid esters such as polymethyl methacrylate; methyl methacrylate- (meth) acrylic acid copolymer; methyl methacrylate- (meth) acrylic acid Ester copolymer; methyl methacrylate-acrylic ester- (meth) acrylic acid copolymer; (meth) methyl acrylate-styrene copolymer (MS resin etc.); methyl methacrylate and alicyclic hydrocarbon group And a copolymer (for example, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate- (meth) acrylate norbornyl copolymer).
  • a polymer based on a poly (meth) acrylic acid C 1-6 alkyl ester such as poly (meth) acrylic acid methyl is used, and more preferably methyl methacrylate is the main component (50 to 100).
  • (Methyl methacrylate resin) having a weight%, preferably 70 to 100 wt%) is used.
  • the base film may be composed of one (meth) acrylic resin, may be composed of a mixture of two or more (meth) acrylic resins, or may be composed of two or more (meth) acrylic resins. ) It may be composed of a copolymer of acrylic resin.
  • the cellulose ester resin is an ester of cellulose and a fatty acid.
  • Specific examples of the cellulose ester resin include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate.
  • these copolymers and those in which a part of the hydroxyl group is modified with another substituent are also included.
  • cellulose triacetate triacetyl cellulose
  • 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” (Fuji Film Co., Ltd.), “Fujitac TD80UF” (Fuji Film Co., Ltd.), and “Fujitac TD80UZ” (Fuji Film (Fujifilm)). Co., Ltd.), “Fujitac TD40UZ” (manufactured by FUJIFILM Corporation), “KC8UX2M” (manufactured by Konica Minolta Opto Corporation), “KC4UY” (manufactured by Konica Minolta Opto Corporation), and the like.
  • the base film may be composed of one kind of cellulose ester resin, may be composed of a mixture of two or more kinds of cellulose ester resins, or may be composed of two or more kinds of cellulose ester resins. It may be composed of a polymer.
  • 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, flame retardancy, and transparency.
  • the polycarbonate-based resin constituting the base film may be a resin called a modified polycarbonate in which the polymer skeleton is modified in order to lower the photoelastic coefficient, a copolymer polycarbonate having improved wavelength dependency, or the like.
  • Polycarbonate resin is available in various products. Examples of commercially available polycarbonate-based resins are all “Panlite” (manufactured by Teijin Chemicals Ltd.), “Iupilon” (manufactured by Mitsubishi Engineering Plastics), “SD Polyca” (Sumitomo Dow). (Manufactured by Dow Chemical Co., Ltd.).
  • the base film may be composed of one type of polycarbonate-based resin, may be composed of a mixture of two or more types of polycarbonate-based resins, or may be composed of a copolymer of two or more types of polycarbonate-based resins. It may be configured.
  • polypropylene resins are preferably used from the viewpoints of stretchability and heat resistance.
  • any appropriate additive may be added to the base film in addition to the above thermoplastic resin.
  • additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, and coloring agents.
  • the content of the thermoplastic resin 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 content of the thermoplastic resin in the base film is less than 50% by weight, the high transparency inherent in the thermoplastic resin may not be sufficiently exhibited.
  • the thickness of the base film can be determined as appropriate, but generally it is preferably 1 to 500 ⁇ m, more preferably 1 to 300 ⁇ m, further preferably 5 to 200 ⁇ m, and more preferably 5 to 150 ⁇ m from the viewpoint of workability such as strength and handleability. Is most preferred.
  • the coating liquid is preferably a polyvinyl alcohol resin solution obtained by dissolving polyvinyl alcohol resin powder in a good solvent (for example, water).
  • a good solvent for example, water
  • the polyvinyl alcohol resin include polyvinyl alcohol resins and derivatives thereof.
  • Polyvinyl alcohol resin derivatives include polyvinyl formal, polyvinyl acetal, etc., as well as polyvinyl alcohol resins modified with olefins such as ethylene and propylene; unsaturated carboxylic acids such as acrylic acid, methacrylic acid and crotonic acid. Denatured; modified with alkyl ester of unsaturated carboxylic acid; modified with acrylamide.
  • the proportion of modification is preferably less than 30 mol%, and more preferably less than 10 mol%.
  • the proportion of modification is preferably less than 30 mol%, and more preferably less than 10 mol%.
  • the average degree of polymerization of the polyvinyl alcohol-based resin is preferably in the range of 100 to 10000, more preferably in the range of 1000 to 10000, still more preferably in the range of 1500 to 8000, and in the range of 2000 to 5000. Most preferably.
  • the average degree of polymerization can be determined by a method defined in JIS K 6726-1994 “Testing method for polyvinyl alcohol”. If the average degree of polymerization is less than 100, it is difficult to obtain a preferable polarization performance, and if it exceeds 10,000, the solubility in a solvent is deteriorated, and it becomes difficult to form a polyvinyl alcohol-based resin layer.
  • the polyvinyl alcohol resin is preferably a saponified product of a polyvinyl acetate resin.
  • the range of the saponification degree is preferably 80 mol% or more, more preferably 90 mol% or more, and particularly preferably 94 mol% or more. If the degree of saponification is too low, the water resistance and heat-and-moisture resistance may not be sufficient when a polarizing laminate film or a polarizing plate is formed. Further, it may be a completely saponified product (having a saponification degree of 100 mol%), but if the saponification degree is too high, the dyeing speed becomes slow, and the production time is required to give sufficient polarization performance. In some cases, a polarizer layer having sufficient polarization performance may not be obtained. Therefore, the saponification degree is preferably 99.5 mol% or less, more preferably 99.0 mol% or less.
  • the saponification degree can be determined by a method defined in JIS K 6726-1994 “Testing method for polyvinyl alcohol”.
  • polyvinyl acetate-based resin examples include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers with other monomers copolymerizable with vinyl acetate.
  • examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.
  • polyvinyl alcohol resins examples include trade names, “PVA124” (degree of saponification: 98.0 to 99.0 mol%), “PVA117” (manufactured by Kuraray Co., Ltd.) Saponification degree: 98.0 to 99.0 mol%), “PVA117H” (saponification degree: 99.5 mol% or more), “PVA624" (saponification degree: 95.0 to 96.0 mol%) and “PVA617” (degree of saponification: 94.5 to 95.5 mol%); “AH-26” (degree of saponification: 97.0 to 98.8 mol%) manufactured by Nippon Synthetic Chemical Industry Co., Ltd.
  • JM-33 degree of saponification: 93.5 to 95.5 mol%)
  • JM-26 degree of saponification: 95.5 to 97.5 mol%)
  • JP -45 degree of saponification: 86.5 to 89.5 mol%)
  • JF-17 degree of saponification: 98.0 to 99.0 mol%)
  • JF-17L degree of saponification: 98.0 to 99.0 mol%)
  • JF-20 degree of saponification: 98.0 to 99.0 mol%).
  • the coating liquid may contain additives such as a plasticizer and a surfactant as necessary.
  • a plasticizer a polyol or a condensate thereof can be used, and examples thereof include glycerin, diglycerin, triglycerin, ethylene glycol, propylene glycol, and polyethylene glycol.
  • the blending amount of the additive is preferably 20% by weight or less of the polyvinyl alcohol resin.
  • the above coating solution is applied to the base film by wire bar coating method; roll coating method such as reverse coating and gravure coating; die coating method; comma coating method; lip coating method; spin coating method; A fountain coating method; a dipping method; and a known method such as a spray method.
  • the coating liquid to both sides of the base film can be carried out one side at a time using the above method, or the base material can be applied using a dipping method, spray coating method, or other special equipment. It can also be applied to both sides of the film simultaneously.
  • the drying temperature and drying time of the coating layer are set according to the type of solvent contained in the coating solution.
  • the drying temperature is, for example, 50 to 200 ° C., preferably 60 to 150 ° C.
  • the drying temperature is preferably 80 ° C. or higher.
  • the drying time is, for example, 2 to 20 minutes.
  • the polyvinyl alcohol-based resin layer may be formed on only one side of the base film or on both sides. When it is formed on both sides, curling of the polarizing laminate film and the film that may occur during the production of the polarizing plate can be suppressed, and two polarizing plates can be obtained from one polarizing laminated film. This is also advantageous.
  • the thickness of the polyvinyl alcohol-based resin layer in the laminated film is preferably 3 to 30 ⁇ m, and more preferably 5 to 20 ⁇ m. If the polyvinyl alcohol-based resin layer has a thickness within this range, the dichroic dye has good dyeability and excellent polarization performance through a stretching step S20 and a dyeing step S30, which will be described later. A child layer can be obtained. When the thickness of the polyvinyl alcohol-based resin layer exceeds 30 ⁇ m, the thickness of the polarizer layer may exceed 10 ⁇ m. Moreover, when the thickness of the polyvinyl alcohol-based resin layer is less than 3 ⁇ m, the film becomes too thin after stretching and the dyeability tends to deteriorate.
  • At least the surface of the base film on which the polyvinyl alcohol resin layer is formed is subjected to corona treatment and plasma. You may perform a process, a flame
  • a polyvinyl alcohol resin layer may be formed on the base film via a primer layer or an adhesive layer.
  • the primer layer can be formed by applying a primer layer forming coating solution to the surface of the substrate film and then drying it.
  • the primer layer forming coating solution contains a component that exhibits a certain degree of strong adhesion to both the base film and the polyvinyl alcohol-based resin layer.
  • the primer layer-forming coating solution usually contains a resin component that imparts such adhesion and a solvent.
  • a thermoplastic resin excellent in transparency, thermal stability, stretchability, and the like is preferably used, and examples thereof include (meth) acrylic resins and polyvinyl alcohol resins. Among these, polyvinyl alcohol resins that give good adhesion are preferably used.
  • polyvinyl alcohol resin examples include polyvinyl alcohol resins and derivatives thereof.
  • Polyvinyl alcohol resin derivatives include polyvinyl formal, polyvinyl acetal, etc., as well as polyvinyl alcohol resins modified with olefins such as ethylene and propylene; unsaturated carboxylic acids such as acrylic acid, methacrylic acid and crotonic acid. Denatured; modified with alkyl ester of unsaturated carboxylic acid; modified with acrylamide.
  • solvent a general organic solvent or an aqueous solvent capable of dissolving the resin component.
  • solvents include, for example, aromatic hydrocarbons such as benzene, toluene and xylene; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; esters such as ethyl acetate and isobutyl acetate; Chlorinated hydrocarbons such as trichlorethylene and chloroform; alcohols such as ethanol, 1-propanol, 2-propanol and 1-butanol.
  • the primer layer is formed using a primer layer forming coating solution containing an organic solvent
  • the base film may be dissolved, so the solvent should be selected in consideration of the solubility of the base film. Is preferred.
  • the primer layer is preferably formed from a coating solution containing water as a solvent.
  • a crosslinking agent may be added to the primer layer forming coating solution.
  • a suitable crosslinking agent is appropriately selected from known ones such as organic and inorganic based on the type of thermoplastic resin used. Examples of the crosslinking agent include epoxy-based, isocyanate-based, dialdehyde-based, and metal-based crosslinking agents.
  • epoxy-based crosslinking agent either one-component curable type or two-component curable type can be used.
  • isocyanate crosslinking agents include tolylene diisocyanate, hydrogenated tolylene diisocyanate, trimethylolpropane-tolylene diisocyanate adduct, triphenylmethane triisocyanate, methylene bis (4-phenylmethane) triisocyanate, isophorone diisocyanate, and ketoximes thereof.
  • a block thing or a phenol block thing etc. are mentioned.
  • dialdehyde-based crosslinking agent examples include glyoxal, malondialdehyde, succindialdehyde, glutardialdehyde, maleidialdehyde, phthaldialdehyde and the like.
  • metal-based crosslinking agent examples include metal salts, metal oxides, metal hydroxides, and organometallic compounds.
  • metal salt, metal oxide, and metal hydroxide examples include divalent or higher valent metals such as magnesium, calcium, aluminum, iron, nickel, zirconium, titanium, silicon, boron, zinc, copper, vanadium, chromium, and tin. Examples thereof include salts, oxides and hydroxides of metals having a valence.
  • An organometallic compound is a compound having in its molecule at least one structure in which an organic group is bonded directly to a metal atom or an organic group is bonded through an oxygen atom, a nitrogen atom, or the like.
  • the organic group means a monovalent or polyvalent group containing at least a carbon element, and can be, for example, an alkyl group, an alkoxy group, an acyl group, or the like. Further, the bond does not mean only a covalent bond, but may be a coordinate bond by coordination of a chelate compound or the like.
  • organometallic compound examples include an organotitanium compound, an organozirconium compound, an organoaluminum compound, and an organosilicon compound.
  • An organometallic compound may be used individually by 1 type, and may use 2 or more types together.
  • organic titanium compounds examples include titanium orthoesters such as tetranormal butyl titanate, tetraisopropyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, tetramethyl titanate; titanium acetylacetonate, titanium tetraacetylacetonate , Titanium chelates such as polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate, titanium triethanolamate, and titanium ethyl acetoacetate; and titanium acylates such as polyhydroxytitanium stearate.
  • titanium orthoesters such as tetranormal butyl titanate, tetraisopropyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, tetramethyl titanate
  • titanium acetylacetonate titanium tetraacetylacetonate
  • organic zirconium compound examples include zirconium normal propionate, zirconium normal butyrate, zirconium tetraacetylacetonate, zirconium monoacetylacetonate, zirconium bisacetylacetonate, zirconium acetylacetonate bisethylacetoacetate and the like.
  • organoaluminum compound examples include aluminum acetylacetonate and aluminum organic acid chelate.
  • organosilicon compound examples include compounds in which the ligands exemplified above for the organotitanium compound and the organozirconium compound are bonded to silicon.
  • high molecular weight crosslinking agents such as methylolated melamine resins and polyamide epoxy resins can also be used.
  • polyamide epoxy resins include “Smiles Resin 650 (30)” and “Smiles Resin 675” (both trade names) sold by Taoka Chemical Co., Ltd.
  • a polyvinyl alcohol-based resin is used as the resin component forming the primer layer
  • a polyamide epoxy resin, a methylolated melamine resin, a dialdehyde-based crosslinking agent, a metal chelate compound-based crosslinking agent, or the like is preferably used as the crosslinking agent.
  • the ratio of the resin component and the crosslinking agent in the primer layer forming coating solution is within the range of about 0.1 to 100 parts by weight of the crosslinking agent with respect to 100 parts by weight of the resin component. It may be appropriately determined depending on the above, and it is particularly preferable to select from the range of about 0.1 to 50 parts by weight.
  • the primer layer forming coating solution preferably has a solid content concentration of about 1 to 25% by weight.
  • the thickness of the primer layer is preferably about 0.05 to 1 ⁇ m, and more preferably 0.1 to 0.4 ⁇ m.
  • the thickness is less than 0.05 ⁇ m, the effect of improving the adhesion between the base film and the polyvinyl alcohol-based resin layer is small, and when the thickness is more than 1 ⁇ m, it is disadvantageous for thinning the polarizing laminated film and the polarizing plate.
  • the method for applying the primer layer-forming coating solution to the substrate film can be the same as in the case of the coating solution for forming the polyvinyl alcohol-based resin layer.
  • the primer layer is applied to the surface (one side or both sides of the base film) to which the coating liquid for forming the polyvinyl alcohol-based resin layer is applied.
  • the drying temperature and drying time of the coating layer comprising the primer layer forming coating solution are set according to the type of solvent contained in the coating solution.
  • the drying temperature is, for example, 50 to 200 ° C., preferably 60 to 150 ° C. When the solvent contains water, the drying temperature is preferably 80 ° C. or higher.
  • the drying time is, for example, 30 seconds to 20 minutes.
  • the order of application to the base film is not particularly limited, and after forming the primer layer on both sides of the base film, the polyvinyl alcohol resin layer may be formed on both sides. And after forming a primer layer and a polyvinyl alcohol-type resin layer in order on one side of a base film, you may form a primer layer and a polyvinyl alcohol-type resin layer in order on the other side of a base film.
  • Stretching step S20 This step is a step of obtaining a stretched film by longitudinally uniaxially stretching a laminated film composed of a base film and a polyvinyl alcohol-based resin layer.
  • Stretching step S20 is a step of longitudinally uniaxially stretching a laminated film by a roll-to-roll stretching method, that is, the laminated film is transported between two nip rolls installed at a distance while the circumferential speed difference between these two nip rolls. A step of stretching the free end longitudinally uniaxially.
  • the laminated film is stretched in the area between the two nip rolls.
  • the stretching step S20 is typically performed continuously while conveying a long laminated film or continuously unwinding a laminated film from a film roll of a long laminated film and conveying this. . Film conveyance can be performed using a guide roll or the like.
  • FIG. 2 is a side view schematically showing an example of the inter-roll stretching method according to the present invention.
  • the laminated film 10 is conveyed and passed through the first nip roll 1, the heating furnace 20 (heating zone), and the second nip roll 2 in this order.
  • the laminated film 10 heated to a predetermined temperature by the heating furnace 20 is longitudinally uniaxially stretched between the first nip roll 1 and the second nip roll 2 to become a stretched film 15 (applied to the stretched film 15 in FIG. 2).
  • Arrows indicate the film transport direction).
  • the inter-roll stretching shown in FIG. 2 does not have other nip rolls involved in stretching between the first nip roll 1 and the second nip roll 2, and thus is a single-stage stretching.
  • FIG. 2 shows an example in which the heating furnace 20 has three heating zones (chambers) 21, 22, and 23 that can be independently temperature controlled.
  • the heating furnace 20 has three heating zones (chambers) 21, 22, and 23 that can be independently temperature controlled.
  • the second heating is performed.
  • the atmospheric temperature in the zone is made 10 ° C. or higher than the atmospheric temperature in the first heating zone.
  • the difference between the atmospheric temperature in the second heating zone and the atmospheric temperature in the first heating zone is preferably 20 ° C. or higher, more preferably 30 ° C. or higher, and further preferably 40 ° C. or higher.
  • the first heating zone is the heating zone 21
  • the second heating zone is the heating zone 22 and / or the heating zone 23. Note that the first heating zone and the second heating zone are always different heating zones.
  • the neck-in rate associated with stretching between rolls can be increased. This is because the ambient temperature of the first heating zone through which the laminated film 10 first passes is set to be relatively low, and the second heating zone whose ambient temperature is 10 ° C. or more higher than the first heating zone is used as the first nip roll on the upstream side. This is considered to be because the restraining force of the laminated film 10 by the first nip roll 1 is weakened by being provided at a position further away from 1.
  • a longitudinally uniaxially stretched film in which the polymer chain of the polyvinyl alcohol resin constituting the polyvinyl alcohol resin layer is highly oriented is provided. Obtainable. A polarizing laminated film or polarizing plate obtained by dyeing such a stretched film with a dichroic dye exhibits good polarizing performance.
  • the neck-in rate is defined by the following equation.
  • Neck-in rate (%) [(W1-W2) ⁇ W1] ⁇ 100
  • W1 is the width of the laminated film 10 before being subjected to the stretching step S20.
  • W2 is the minimum width of the stretched film 15 after the laminate film 10 is stretched.
  • Examples of the method for constructing a plurality of heating zones include the following (a) and (b).
  • the heating furnace examples include a heating furnace using hot air, and a furnace provided with heaters such as an infrared heater, a halogen heater, and a panel heater that are installed above and below the laminated film and heated by radiant heat.
  • a heating furnace using hot air examples include a furnace provided with heaters such as an infrared heater, a halogen heater, and a panel heater that are installed above and below the laminated film and heated by radiant heat.
  • the 1st and / or 2nd nip rolls 1 and 2 can also be installed in a heating zone, in order to prevent adhesion with a laminated film and a nip roll, installing in the heating zone is preferable.
  • the ambient temperature in the heating zone near the upstream first nip roll 1 is relatively low.
  • the first heating zone is defined as a heating zone having the lowest ambient temperature. It is preferable to do.
  • zones other than the first heating zone may be the heating zone having the lowest atmospheric temperature.
  • the heating zone 21 or 22 can be the heating zone having the lowest ambient temperature, and preferably the heating zone 21 is the heating zone having the lowest ambient temperature.
  • the second heating zone is preferably arranged at a position as far as possible from the first nip roll 1 on the upstream side, for example, the laminated film 10 passes through last.
  • the heating zone is preferably the second heating zone.
  • a zone other than the heating zone through which the laminated film 10 passes last may be set as the second heating zone.
  • the heating zone 22 or 23 can be the second heating zone, and preferably the heating zone 23 is the second heating zone.
  • heating zones There may be a plurality of heating zones provided between the first nip roll 1 and the second nip roll 2, for example, it may be constituted by two heating zones, or it may be constituted by three heating zones as in the example of FIG. It may be made up of four or more heating zones.
  • FIG. 3 is an example in the case of having four heating zones.
  • the heating zone 21, 22 or 23 (preferably the heating zone 21 or 22, more preferably the heating zone 21) can be the heating zone having the lowest ambient temperature.
  • the heating zone 22, 23 or 24 (preferably the heating zone 23 or 24, more preferably the heating zone 24) can be set as the second heating zone.
  • the atmospheric temperature of the heating zone in which stretching is performed is set to a temperature that exhibits fluidity to such an extent that the entire polyvinyl alcohol-based resin layer and the base film can be stretched.
  • the range of the melting point of the film ⁇ 30] ° C. to the melting point of the base film + 30 ° C. more preferably the range of the melting point of the base film ⁇ 30] ° C. to the melting point of the base film + 5 ° C. More preferably, it is in the range of [melting point of substrate film ⁇ 25] ° C. to [melting point of substrate film] ° C.
  • the melting point means the highest melting point among melting points of the plurality of resin layers.
  • the ambient temperature is within the above range, and more preferably 120 ° C. or higher.
  • the draw ratio of the laminated film 10 can be appropriately selected according to the desired polarization characteristics, it is preferably more than 5 times the original length of the laminated film, and preferably 8 times or less.
  • the draw ratio is 5 times or less, the polyvinyl alcohol-based resin layer is not sufficiently oriented, and the degree of polarization of the polarizer layer may not be sufficiently high.
  • the draw ratio exceeds 8 times, the film is likely to be broken during stretching, and the thickness of the stretched film becomes unnecessarily thin, and the workability and handleability in subsequent processes may be reduced.
  • the stretching step S20 can include a heat setting treatment step as a subsequent step of the longitudinal uniaxial stretching treatment.
  • the heat setting process is a process of performing a heat treatment at a temperature equal to or higher than the crystallization temperature while maintaining the tensioned state with the end of the stretched film held by a clip. By this heat setting treatment, crystallization of the polyvinyl alcohol-based resin layer is promoted.
  • a heat treatment method a method similar to the heating method in the heating zone described above can be used in a state where the end of the stretched film is held by a clip.
  • the temperature of the heat setting treatment is preferably in the range of [atmosphere temperature of the second heating zone] ° C. to [atmosphere temperature of the second heating zone ⁇ 80] ° C., and [atmosphere temperature of the second heating zone] ° C. to [ It is more preferable that the ambient temperature in the second heating zone is ⁇ 50] ° C.
  • the heat setting treatment step When the heat setting treatment step is performed between the first nip roll 1 and the second nip roll 2, it can be performed in any heating zone other than the first heating zone and the second heating zone.
  • the heat setting treatment can also be performed in the heating zone after passing through the second nip roll.
  • it When carrying out the heat setting treatment step, it is typically carried out in a heating zone through which the laminated film passes last.
  • Dyeing step S30 the polyvinyl alcohol-based resin layer of the stretched film is dyed with a dichroic dye and adsorbed and oriented to form a polarizer layer. Through this step, a polarizing laminated film in which a polarizer layer is laminated on one side or both sides of a base film is obtained.
  • the dyeing step S30 is typically performed continuously while conveying a long stretched film or continuously unwinding a stretched film from a film roll of a long stretched film and transporting the stretched film. . Film conveyance can be performed using a guide roll or the like.
  • dichroic dye examples include iodine and dichroic organic dyes.
  • dichroic organic dye examples include, for example, 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, Splat Blue G, Splat Blue GL, Splat Orange GL , Direct Sky Blue, Direct First Orange S, First Black, etc.
  • a dichroic dye may be used individually by 1 type, and may use 2 or more types together.
  • the dyeing step can be performed by immersing the entire stretched film in a solution (dye solution) containing a dichroic dye.
  • a solution in which the above dichroic dye is dissolved in a solvent can be used.
  • 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 in the dyeing solution is preferably 0.01 to 10% by weight, more preferably 0.02 to 7% by weight, and further preferably 0.025 to 5% by weight. preferable.
  • iodine When iodine is used as the dichroic dye, it is preferable to further add an iodide to the dyeing solution containing iodine because the dyeing efficiency can be further improved.
  • 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 in the dyeing solution is preferably 0.01 to 20% by weight. Of the iodides, it is preferable to add potassium iodide.
  • 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. Preferably, it is in the range of 1: 7 to 1:70.
  • the immersion time of the stretched film in the dyeing solution is usually in the range of 15 seconds to 15 minutes, preferably 30 seconds to 3 minutes.
  • 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.
  • Embodiments in this case are as follows: 1) In the stretching step S20, after the stretching process is performed at a lower ratio than the target, the stretching process is performed so that the total stretching ratio becomes the target ratio during the dyeing process in the dyeing process S30.
  • the dyeing step S30 can include a cross-linking treatment step performed subsequent to the dyeing treatment.
  • the crosslinking treatment can be performed by immersing the dyed film in a solution containing a crosslinking agent (crosslinking solution).
  • a crosslinking agent conventionally known substances can be used, and examples thereof include boron compounds such as boric acid and borax, glyoxal, and glutaraldehyde.
  • a crosslinking agent may be used individually by 1 type, and may use 2 or more types together.
  • the crosslinking solution can be a solution in which a crosslinking agent is dissolved in a solvent.
  • a 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, and more preferably in the range of 6 to 15% by weight.
  • the crosslinking solution can contain iodide.
  • iodide By adding iodide, the polarization performance in the plane of the polarizer layer can be made more uniform.
  • 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 in the crosslinking solution is preferably 0.05 to 15% by weight, and more preferably 0.5 to 8% by weight.
  • the immersion time of the dyed film in the crosslinking solution is usually 15 seconds to 20 minutes, and preferably 30 seconds to 15 minutes.
  • the temperature of the crosslinking solution is preferably in the range of 10 to 90 ° C.
  • the crosslinking treatment can be performed simultaneously with the dyeing treatment by blending a crosslinking agent in the dyeing solution. Further, a stretching process may be performed during the crosslinking process.
  • the specific mode for carrying out the stretching treatment during the crosslinking treatment is as described above.
  • the washing process usually includes a water washing process.
  • the water washing treatment can be performed by immersing the film after the dyeing treatment or after the crosslinking treatment in pure water such as ion exchange water or distilled water.
  • the water washing temperature is usually 3 to 50 ° C, preferably 4 to 20 ° C.
  • the immersion time in water is usually 2 to 300 seconds, preferably 3 to 240 seconds.
  • the washing step may be a combination of a water washing step and a washing step with an iodide solution.
  • liquids such as methanol, ethanol, isopropyl alcohol, butanol, and propanol can be appropriately contained in the cleaning liquid used in the water cleaning step and / or the cleaning process using the iodide solution.
  • any appropriate method such as natural drying, blow drying, or heat drying can be adopted as the drying step performed after the washing step.
  • the drying temperature is usually 20 to 95 ° C.
  • the drying time is usually about 1 to 15 minutes.
  • the polarizing laminated film obtained as described above can be used as a polarizing element as it is, and is also useful as an intermediate for producing a polarizing plate comprising a polarizer layer and a protective film.
  • the thickness of the polarizer layer of the polarizing laminate film is 10 ⁇ m or less, preferably 7 ⁇ m or less. By setting the thickness of the polarizer layer to 10 ⁇ m or less, a thin polarizing laminated film can be formed.
  • the manufacturing method of the polarizing plate of this invention is the process of preparing the above-mentioned polarizing laminated film, bonding process S40 which bonds a protective film on the polarizer layer of a polarizing laminated film, and obtains a bonding film, bonding A peeling step S50 for peeling and removing the base film from the film is included in this order.
  • Pasting step S40 This step is a step of obtaining a bonding film by bonding a protective film on the polarizer layer of the polarizing laminated film, that is, on the surface opposite to the substrate film side of the polarizer layer.
  • the protective film can be bonded to the polarizer layer using an adhesive or a pressure-sensitive adhesive.
  • a protective film is normally bonded on the polarizer layers on both surfaces. In this case, these protective films may be the same type of protective film or different types of protective films.
  • the protective film is, for example, a polyolefin resin such as a chain polyolefin resin (such as a polypropylene resin) or a cyclic polyolefin resin (such as a norbornene resin); a cellulose ester resin such as cellulose triacetate or cellulose diacetate;
  • the film may be a polyester resin such as terephthalate, polyethylene naphthalate or polybutylene terephthalate; a polycarbonate resin; a (meth) acrylic resin; or a mixture or copolymer thereof. Examples of commercially available products such as cyclic polyolefin resins and films thereof, and cellulose triacetate are as described above.
  • the protective film may be a protective film having both optical functions such as a retardation film and a brightness enhancement film.
  • a retardation film provided with an arbitrary retardation value by stretching a resin film made of the above material (uniaxial stretching or biaxial stretching) or forming a liquid crystal layer or the like on the film; can do.
  • An optical layer such as a hard coat layer, an antiglare layer, or an antireflection layer can be formed on the surface of the protective film opposite to the polarizer layer.
  • the method for forming these optical layers on the surface of the protective film is not particularly limited, and a known method can be used.
  • the optical layer may be formed in advance on the protective film prior to the bonding step S40, or may be formed after the bonding step S40 or after the peeling step S50 described later.
  • plasma treatment, corona treatment, ultraviolet irradiation treatment, flame (flame) is applied to the surface of the protective film on the polarizer layer side in order to improve adhesion to the polarizer layer.
  • Treatment, saponification treatment, and other surface treatments can be performed, and among these, plasma treatment, corona treatment, or saponification treatment is preferably performed.
  • plasma treatment, corona treatment, or saponification treatment is usually performed.
  • a saponification process is normally performed.
  • the saponification treatment include a method of immersing in an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide.
  • the thickness of the protective film is preferably thin, but if it is too thin, the strength decreases and the processability is poor. On the other hand, when too thick, problems, such as transparency falling and the curing time required after bonding, will arise. Therefore, the thickness of the protective film is preferably 90 ⁇ m or less, more preferably 5 to 60 ⁇ m, and still more preferably 5 to 50 ⁇ m. From the viewpoint of thinning the polarizing plate, the total thickness of the polarizer layer and the protective film is preferably 100 ⁇ m or less, more preferably 90 ⁇ m or less, and further preferably 80 ⁇ m or less.
  • a water-based adhesive or a photocurable adhesive can be used as the adhesive.
  • the water-based adhesive include an adhesive made of a polyvinyl alcohol-based resin aqueous solution and a water-based two-component urethane emulsion adhesive.
  • a cellulose ester resin film that has been surface-treated (hydrophilized) by a saponification treatment or the like is used as a protective film, it is preferable to use a water-based adhesive composed of an aqueous polyvinyl alcohol resin solution.
  • Polyvinyl alcohol resins include vinyl alcohol homopolymers obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith.
  • a polyvinyl alcohol copolymer obtained by saponifying a polymer or a modified polyvinyl alcohol polymer obtained by partially modifying the hydroxyl group thereof can be used.
  • the water-based adhesive can include additives such as polyvalent aldehydes, water-soluble epoxy compounds, melamine compounds, zirconia compounds, and zinc compounds. When an aqueous adhesive is used, the thickness of the adhesive layer obtained therefrom is usually 1 ⁇ m or less.
  • a water-based adhesive is applied onto the polarizer layer and / or protective film of the polarizing laminated film, and these films are bonded through the adhesive layer, preferably pressed and bonded using a bonding roll or the like.
  • a pasting process is carried out by making it.
  • the coating method of the water-based adhesive (same for the photo-curable adhesive) is not particularly limited, and casting method, Meyer bar coating method, gravure coating method, comma coater method, doctor plate method, die coating method, dip coating method A conventionally known method such as a spraying method can be used.
  • drying can be performed, for example, by introducing the film into a drying furnace.
  • the drying temperature (drying furnace temperature) is preferably 30 to 90 ° C. When it is lower than 30 ° C., the protective film tends to be peeled off from the polarizer layer. If the drying temperature exceeds 90 ° C., the polarizing performance of the polarizer layer may be deteriorated by heat.
  • the drying time can be about 10 to 1000 seconds. From the viewpoint of productivity, the drying time is preferably 60 to 750 seconds, and more preferably 150 to 600 seconds.
  • a curing step of curing for about 12 to 600 hours at room temperature or a slightly higher temperature, for example, a temperature of about 20 to 45 ° C. may be provided.
  • the curing temperature is generally set lower than the drying temperature.
  • the photocurable adhesive refers to an adhesive that cures when irradiated with active energy rays such as ultraviolet rays.
  • an adhesive containing a polymerizable compound and a photopolymerization initiator, an adhesive containing a photoreactive resin, and a binder examples include those containing a resin and a photoreactive cross-linking agent.
  • the polymerizable compound include photopolymerizable monomers such as a photocurable epoxy monomer, a photocurable acrylic monomer, and a photocurable urethane monomer, and oligomers derived from the photopolymerizable monomer.
  • a photoinitiator what contains the substance which generate
  • an adhesive containing a photocurable epoxy monomer and a photocationic polymerization initiator can be preferably used.
  • a drying process is performed as necessary (such as when the photocurable adhesive contains a solvent), and then light is irradiated by activating active energy rays.
  • a curing step for curing the curable adhesive is performed.
  • 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.
  • 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 the irradiation intensity in the wavelength region effective for activating the polymerization initiator is 0.1 to 6000 mW / cm 2. It is preferable to set to. When the irradiation intensity is 0.1 mW / cm 2 or more, the reaction time does not become too long, and when the irradiation intensity is 6000 mW / cm 2 or less, the light emitted from the light source and the light generated by the heat generated when the photocurable adhesive is cured. There is little risk of yellowing of the curable adhesive and deterioration of the polarizer layer.
  • the light irradiation time for the photocurable adhesive is also determined appropriately depending on the composition of the photocurable adhesive, and the integrated light amount expressed as the product of the irradiation intensity and the irradiation time is 10 to 10,000 mJ / cm 2. It is preferable to set to. When the integrated light quantity is 10 mJ / cm 2 or more, a sufficient amount of active species derived from the polymerization initiator can be generated to advance the curing reaction more reliably, and when it is 10000 mJ / cm 2 or less, the irradiation time is long. It does not become too much, and good productivity can be maintained.
  • the thickness of the adhesive layer after irradiation with active energy rays is usually about 0.001 to 5 ⁇ m, preferably 0.01 to 2 ⁇ m, more preferably 0.01 to 1 ⁇ m.
  • the pressure-sensitive adhesive that can be used for bonding the protective film is usually based on an acrylic resin, styrene resin, silicone resin, or the like, and a crosslinking agent such as an isocyanate compound, an epoxy compound, or an aziridine compound. It consists of the added adhesive composition. Furthermore, it can also be set as the adhesive layer which contains microparticles
  • the thickness of the pressure-sensitive adhesive layer can be 1 to 40 ⁇ m, but it is preferably applied thinly, as long as it does not impair the workability and durability characteristics, and specifically 3 to 25 ⁇ m. A thickness of 3 to 25 ⁇ m has good processability and is suitable for suppressing dimensional change of the polarizer layer.
  • the pressure-sensitive adhesive layer is less than 1 ⁇ m, the tackiness is lowered, and when it exceeds 40 ⁇ m, problems such as the pressure-sensitive adhesive protruding easily occur.
  • the protective film In the method of bonding the protective film to the polarizer layer using the pressure-sensitive adhesive, after the pressure-sensitive adhesive layer is provided on the protective film surface, it may be bonded to the polarizer layer, or the pressure-sensitive adhesive layer on the surface of the polarizer layer. After providing, you may paste a protective film here.
  • the method for forming the pressure-sensitive adhesive layer is not particularly limited, and a pressure-sensitive adhesive composition (pressure-sensitive adhesive solution) containing each component including the above-mentioned base polymer is applied to the protective film surface or the polarizer layer surface.
  • a pressure-sensitive adhesive composition pressure-sensitive adhesive solution
  • the protective film and the polarizer layer may be bonded together, or after forming the pressure-sensitive adhesive layer on the separator (release film), the pressure-sensitive adhesive layer is applied to the surface of the protective film. Or you may make it transfer on a polarizing film surface, and then affix a protective film and a polarizer layer.
  • surface treatment such as corona treatment may be applied to the protective film surface or the polarizer layer surface, or one or both surfaces of the pressure-sensitive adhesive layer as necessary. Good.
  • Peeling step S50 This step is a step of removing the substrate film from the bonded film obtained by bonding the protective film. Through this step, a polarizing plate in which a protective film is laminated on the polarizer layer can be obtained.
  • the polarizing laminated film has a polarizer layer on both sides of the base film, and a protective film is bonded to both of these polarizer layers, this peeling step S50 allows the two polarizing laminate films to be removed. A sheet of polarizing plate is obtained.
  • the method of peeling and removing the base film is not particularly limited, and can be peeled by the same method as the separator (peeling film) peeling step performed by a normal pressure-sensitive adhesive polarizing plate.
  • the base film may be peeled off as it is, or after the bonding step S40, it may be wound up into a roll and peeled off in the subsequent step.
  • the polarizing plate produced as described above can be used as an optical film in which other optical layers are laminated in practical use.
  • the protective film may have the function of such an optical layer.
  • a reflective polarizing film that transmits a certain kind of polarized light and reflects polarized light having the opposite properties; a film with an antiglare function having an uneven shape on the surface; a film with a surface antireflection function A reflective film having a reflective function on the surface; a transflective film having both a reflective function and a transmissive function; and a viewing angle compensation film.
  • DBEF (manufactured by 3M, Sumitomo 3M Co., Ltd. in Japan) can be used as a commercial product corresponding to a reflective polarizing film that transmits certain types of polarized light and reflects polarized light that exhibits the opposite properties.
  • APF (manufactured by 3M, available from Sumitomo 3M Limited in Japan).
  • the viewing angle compensation film examples include an optical compensation film in which a liquid crystal compound is applied to the substrate surface, and is oriented / fixed, a retardation film made of a polycarbonate resin, a retardation film made of a cyclic polyolefin resin, and the like. .
  • WV film manufactured by Fujifilm Corporation
  • NH film JX Nippon Mining & Metals. Energy Co., Ltd.
  • NR Film manufactured by JX Nippon Oil & Energy Corporation
  • a long base film having a three-layer structure in which a resin layer composed of a propylene homopolymer (“Sumitomo Noblen FLX80E4” manufactured by Sumitomo Chemical Co., Ltd., melting point Tm 163 ° C.) is disposed on a multilayer extruder It was produced by the coextrusion molding used.
  • the total thickness of the base film was 100 ⁇ m, and the thickness ratio (FLX80E4 / W151 / FLX80E4) of each layer was 3/4/3.
  • 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., and the concentration was 8% by weight.
  • a polyvinyl alcohol aqueous solution was prepared and used as a coating liquid for forming a polyvinyl alcohol-based resin layer.
  • the base film surface opposite to the surface on which the polyvinyl alcohol-based resin layer is formed is treated in the same manner as described above to sequentially form a primer layer and a polyvinyl alcohol-based resin layer on both surfaces of the base film.
  • stretched film (stretching process) Using the stretching apparatus shown in FIG. 2, while continuously transporting the laminated film prepared in (3) above, a longitudinal uniaxial stretching process (free end uniaxial stretching in the film transport direction) is performed by stretching between rolls, A stretched film was prepared.
  • the ambient temperatures in the heating zones 21, 22, and 23 were 100 ° C, 120 ° C, and 150 ° C, respectively.
  • the draw ratio in the drawing step was 5.80 times, and the polyvinyl alcohol resin layer in the drawn film had a thickness of 4.4 ⁇ m on one side and 4.6 ⁇ m on the other side. Moreover, it was 61.0% when the neck-in rate was measured about the obtained stretched film based on the said formula.
  • the adhesive aqueous solution was applied on both polarizer layers, and then the saponification treatment was applied to the bonding surface.
  • a film transparent protective film made of triacetylcellulose (TAC) (“KC4UY” manufactured by Konica Minolta Opto Co., Ltd.), thickness 40 ⁇ m] on the polarizer layer and passing between a pair of laminating rolls It bonded and produced the bonding film which consists of layer structure of TAC / polarizer layer / primer layer / base material film / primer layer / polarizer layer / TAC (bonding process).
  • TAC triacetylcellulose
  • the laminated film is peeled off at the interface between the base film and the primer layer, and a film composed of TAC / polarizer layer / primer layer / base film and a polarizing plate composed of primer layer / polarizer layer / TAC. Then, the base film was peeled off from the former film and removed to obtain another polarizing plate. In the process of peeling the base film, no troubles such as breakage occurred.
  • Example 2 In the stretching step, a polarizing laminated film was produced in the same manner as in Example 1 except that the atmospheric temperatures in the heating zones 21, 22, and 23 were 100 ° C, 120 ° C, and 140 ° C, respectively (stretching ratio in the stretching step) Is 5.80 times). When the neck-in rate of the stretched film was measured based on the above formula, it was 60.8%.
  • ⁇ Comparative Example 1> In the stretching step, a polarizing laminated film was produced in the same manner as in Example 1 except that the atmospheric temperatures in the heating zones 21, 22, and 23 were 150 ° C, 150 ° C, and 100 ° C, respectively (stretching ratio in the stretching step) Is 5.80 times). It was 58.0% when the neck-in rate was measured about the stretched film based on the said formula.
  • the method of the present invention it is possible to perform longitudinal uniaxial stretching of a laminated film with a high neck-in ratio without excessively increasing the draw ratio, so that a polarizing laminated film or a polarizing plate having good polarization performance can be stably produced. Can be manufactured.

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  • Engineering & Computer Science (AREA)
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  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Dispersion Chemistry (AREA)
  • Polarising Elements (AREA)
  • Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Nonlinear Science (AREA)
  • Liquid Crystal (AREA)
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  • Crystallography & Structural Chemistry (AREA)
PCT/JP2014/056383 2013-03-07 2014-03-05 偏光性積層フィルムの製造方法および偏光板の製造方法 WO2014136984A1 (ja)

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JP2011150313A (ja) * 2009-12-21 2011-08-04 Sumitomo Chemical Co Ltd 偏光板の製造方法
JP2012230282A (ja) * 2011-04-27 2012-11-22 Konica Minolta Advanced Layers Inc λ／４位相差フィルムの製造方法、長尺状偏光板、及び液晶表示装置

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Publication number Priority date Publication date Assignee Title
JP2011150313A (ja) * 2009-12-21 2011-08-04 Sumitomo Chemical Co Ltd 偏光板の製造方法
JP2012230282A (ja) * 2011-04-27 2012-11-22 Konica Minolta Advanced Layers Inc λ／４位相差フィルムの製造方法、長尺状偏光板、及び液晶表示装置

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