WO2016002504A1 - Method for producing polarizing plate having protective films on both surfaces thereof - Google Patents

Method for producing polarizing plate having protective films on both surfaces thereof Download PDF

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Publication number
WO2016002504A1
WO2016002504A1 PCT/JP2015/067316 JP2015067316W WO2016002504A1 WO 2016002504 A1 WO2016002504 A1 WO 2016002504A1 JP 2015067316 W JP2015067316 W JP 2015067316W WO 2016002504 A1 WO2016002504 A1 WO 2016002504A1
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Prior art keywords
protective film
iodine
film
polarizing plate
polarizer
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PCT/JP2015/067316
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French (fr)
Japanese (ja)
Inventor
雄一朗 九内
Original Assignee
住友化学株式会社
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Application filed by 住友化学株式会社 filed Critical 住友化学株式会社
Priority to CN201580035235.7A priority Critical patent/CN106662690B/en
Priority to KR1020167036462A priority patent/KR102441217B1/en
Priority to JP2015536325A priority patent/JPWO2016002504A1/en
Publication of WO2016002504A1 publication Critical patent/WO2016002504A1/en

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    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00Optical elements other than lenses
    • G02B5/30Polarising elements

Definitions

  • the present invention relates to a method for producing a polarizing plate with a double-sided protective film in which protective films are bonded to both surfaces of an iodine-based polarizer, and more specifically, a protective film having a low moisture permeability is sequentially bonded to both surfaces of an iodine-based polarizer.
  • the present invention relates to a method for producing a polarizing plate with a double-sided protective film.
  • the polarizing plate has been widely used in display devices such as liquid crystal display devices, especially in recent years for various mobile devices such as smartphones.
  • As a polarizing plate the thing of the structure which bonded the protective film on the single side
  • the polarizer itself has low heat and humidity resistance, and its polarization characteristics are likely to deteriorate in a wet and heat environment.
  • a triacetyl cellulose film has been used as a protective film for protecting a polarizer, but since a triacetyl cellulose film has high moisture permeability, a polarizing plate using this film as a protective film is particularly iodine-based as a polarizer. In the case of using a polarizer, there has been a problem that the heat and humidity resistance is still insufficient.
  • a protective film with low moisture permeability is bonded to both sides of the iodine polarizer, moisture penetration from the outside is reduced, so that the moisture and heat resistance of the polarizing plate can be improved.
  • a conventional polarizing plate with a double-sided protective film using a protective film with low moisture permeability on both sides is cross-linked when subjected to a heat resistance test that is exposed to a higher temperature environment than a general wet heat resistance test. It is the inventor of the present invention that light leakage occurs under Nicol (a phenomenon in which red color light leaks from the polarizing plate and the polarizing plate appears red, also referred to as red discoloration), or polarization characteristics deteriorate. It became clear by examination. This problem of poor heat resistance becomes more conspicuous as the thickness of the iodine polarizer is smaller.
  • the present invention is a polarizing plate in which a protective film having low moisture permeability is bonded to both surfaces of an iodine-based polarizer, and a method for producing a polarizing plate with a double-sided protective film that combines heat and moisture resistance, And it aims at provision of the polarizing plate with a double-sided protective film which combines heat-and-moisture resistance and heat resistance.
  • This invention provides the manufacturing method of the polarizing plate with a double-sided protective film shown below, and the polarizing plate with a double-sided protective film.
  • a polarizing plate with a double-sided protective film is obtained by laminating a second protective film on the outer surface of the iodine-type polarizer in the polarizing plate with a single-sided protective film including the iodine-type polarizer and the first protective film laminated on one side thereof.
  • Including a step of obtaining The first protective film and the second protective film is a thermoplastic film of less moisture permeability 150 g / m 2/24 hr or, The manufacturing method of the polarizing plate with a double-sided protective film whose moisture content of the said iodine type polarizer when bonding a said 2nd protective film is less than 8 weight%.
  • a method for producing a polarizing plate with a double-sided protective film which is a polarizing plate in which a protective film having low moisture permeability is bonded to both sides of an iodine-based polarizer, which has both moisture heat resistance and heat resistance.
  • the polarizing plate which bonded the protective film with low moisture permeability on both surfaces of an iodine type polarizer Comprising:
  • the polarizing plate with a double-sided protective film which has both heat-and-moisture resistance and heat resistance can be provided.
  • the manufacturing method of the polarizing plate with a double-sided protective film according to the present invention may include the following steps as shown in FIG.
  • Step S10 of preparing a polarizing plate with a single-sided protective film including an iodine-based polarizer and a first protective film laminated on one side thereof (hereinafter also referred to as “polarizing plate with a single-sided protective film S10”), and (2) Step S20 for obtaining a polarizing plate with a double-sided protective film by bonding the second protective film to the outer surface of the iodine-based polarizer in the polarizing plate with a single-sided protective film (hereinafter referred to as “Polarizer production step S20 with double-sided protective film”). Also called).
  • the first protective film and the second protective film are sequentially bonded to the iodine polarizer.
  • the 1st protective film bonded to one side of an iodine type polarizer, and the 2nd protective film bonded to the other side as a moisture permeability using a thermoplastic resin film of low moisture permeability is not more than 150g / m 2 / 24hr.
  • the water content of the iodine-based polarizer when the second protective film is bonded to the iodine-based polarizer is less than 8% by weight.
  • a protective film with low moisture permeability is bonded to both surfaces of the iodine-based polarizer to form a polarizing plate.
  • the moisture content of the iodine-based polarizer is during the process of manufacturing the polarizing plate with a double-sided protective film, and is in any stage before the second protective film is bonded to the iodine-based polarizer.
  • This can be achieved by providing a step S30 (hereinafter also referred to as “moisture percentage reduction step S30”) for performing a moisture percentage reduction process on the film including the polarizer (see FIG. 1).
  • Polarizing plate preparation process S10 with a single-sided protective film This step is a step of preparing (preparing) a polarizing plate 100 with a single-sided protective film as shown in FIG. 2, for example, including the iodine-based polarizer 5 and the first protective film 10 laminated on one side thereof. As shown in FIG. 2, the first protective film 10 is usually bonded (adhered and fixed) to one surface of the iodine-based polarizer 5 via the first adhesive layer 15.
  • the iodine-based polarizer 5 is a polarizer in which iodine is adsorbed and oriented as a dichroic dye. Specifically, the iodine-based polarizer 5 is obtained by adsorbing and orienting iodine to a uniaxially stretched polyvinyl alcohol resin layer (or film). Can be.
  • the thickness of the iodine-based polarizer 5 can be, for example, 30 ⁇ m or less, and further 20 ⁇ m or less, but in particular for mobile devices, it is preferably 10 ⁇ m or less from the viewpoint of thinning the polarizing plate with a double-sided protective film, More preferably, it is 8 ⁇ m or less.
  • the thickness of the iodine-based polarizer 5 is usually 2 ⁇ m or more.
  • the concentration of iodine is increased, and the concentration of iodine complex existing in the vicinity of the interface with the protective film laminated on both sides is also increased. It is easy to receive. Therefore, the heat-and-moisture resistance tends to be lower as the thickness of the iodine-based polarizer 5 is smaller.
  • the thickness of the iodine-type polarizer 5 is reduced and the concentration of iodine is further increased, the iodine-type polarizer 5 is easily affected by moisture remaining in the iodine-type polarizer and heat resistance is likely to be lowered.
  • the heat-and-moisture resistance and heat resistance are likely to be lower as the thickness of the iodine-based polarizer 5 is smaller.
  • the present invention is particularly advantageous when the thickness of the iodine-based polarizer 5 is small.
  • a saponified polyvinyl acetate resin can be used as the polyvinyl alcohol resin constituting the polyvinyl alcohol resin layer.
  • the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith.
  • examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth) acrylamides having an ammonium group.
  • (meth) acryl means at least one selected from acrylic and methacrylic. The same applies to cases such as “(meth) acryloyl”.
  • a film obtained by forming a film of the polyvinyl alcohol resin constitutes the iodine polarizer 5.
  • the method for forming the polyvinyl alcohol-based resin is not particularly limited, and can be formed by a known method, but it is easy to obtain the iodine-based polarizer 5 having a small thickness, and the iodine-based polarization of the thin film in the process. Since the handleability of the child 5 is also excellent, a method of forming a film by coating a solution of a polyvinyl alcohol resin as described later on the base film is preferable.
  • the degree of saponification of the polyvinyl alcohol-based resin can be in the range of 80.0 to 100.0 mol%, preferably in the range of 90.0 to 99.5 mol%, more preferably 94.0. It is in the range of ⁇ 99.0 mol%.
  • the degree of saponification is less than 80.0 mol%, the water resistance and heat-and-moisture resistance of the resulting polarizing plate with a double-sided protective film are lowered.
  • a polyvinyl alcohol-based resin having a saponification degree exceeding 99.5 mol% is used, the iodine dyeing speed becomes slow, the productivity decreases, and the iodine-based polarizer 5 having sufficient polarization performance cannot be obtained. There is.
  • the degree of saponification is the unit ratio (mol%) of the ratio of acetate groups (acetoxy groups: —OCOCH 3 ) contained in polyvinyl acetate resin, which is a raw material for polyvinyl alcohol resins, to hydroxyl groups by the saponification process.
  • the following formula: Saponification degree (mol%) 100 ⁇ (number of hydroxyl groups) ⁇ (number of hydroxyl groups + number of acetate groups) Defined by The degree of saponification can be determined according to JIS K 6726-1994. The higher the degree of saponification, the higher the proportion of hydroxyl groups, and thus the lower the proportion of acetate groups that inhibit crystallization.
  • the polyvinyl alcohol resin may be a modified polyvinyl alcohol partially modified.
  • the proportion of modification is preferably less than 30 mol%, and more preferably less than 10%. When modification exceeding 30 mol% is performed, it is difficult to adsorb iodine, and it is difficult to obtain an iodine-based polarizer 5 having sufficient polarization performance.
  • the average degree of polymerization of the polyvinyl alcohol-based resin is preferably 100 to 10,000, more preferably 1500 to 8000, and further preferably 2000 to 5000.
  • the average degree of polymerization of the polyvinyl alcohol resin can also be determined according to JIS K 6726-1994.
  • the first protective film 10 has a light-transmitting property (preferably optically clear) a thermoplastic resin, and the moisture permeability is less film 150g / m 2 / 24hr.
  • the moisture permeability including the moisture permeability of the second protective film described later, is a temperature of 40 ° C. and a relative humidity of 90 measured according to JIS Z 0208-1976 “Moisture permeability test method for moisture-proof packaging materials (cup method)”. Percent moisture permeability.
  • Moisture permeability is preferably 100g / m 2 / 24hr or less.
  • the moisture permeability of the first protective film 10 below 150g / m 2 / 24hr, or used as moisture permeability is lower in the thermoplastic resin constituting the film, or by increasing the thickness of the film, onto the film
  • a barrier layer having low moisture permeability may be provided.
  • the thermoplastic resin constituting the first protective film 10 is not particularly limited as long as the above moisture permeability can be achieved. However, since the moisture permeability is low and the thickness of the first protective film 10 can be reduced, a chain polyolefin resin (polypropylene type) is used. Resins), polyolefin resins such as cyclic polyolefin resins (norbornene resins, etc.); polyester resins such as polyethylene terephthalate resins; polycarbonate resins; (meth) acrylic resins; polystyrene resins; A mixture, copolymer or the like is preferably used.
  • the first protective film 10 can also be a protective film having an optical function such as a retardation film and a brightness enhancement film.
  • a retardation film provided with an arbitrary retardation value by stretching a film made of the thermoplastic resin (uniaxial stretching or biaxial stretching) or by forming a liquid crystal layer or the like on the film. It can be.
  • chain polyolefin resin examples include a homopolymer of a chain olefin such as a polyethylene resin and a polypropylene resin, and a copolymer composed of two or more chain olefins.
  • Cyclic polyolefin-based resin is a general term for resins that are polymerized using cyclic olefins as polymerization units.
  • Specific examples of 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.
  • 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 dicarboxylic acid or a derivative thereof can be used, and examples thereof include terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalenedicarboxylate.
  • a diol can be used as the polyhydric alcohol, and examples thereof include ethylene glycol, propanediol, butanediol, neopentyl glycol, and cyclohexanedimethanol.
  • polyester resin examples include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethyl terephthalate, and polycyclohexanedimethyl naphthalate.
  • Polycarbonate resin is made of a polymer in which monomer units are bonded via a carbonate group.
  • the polycarbonate-based resin may be a resin called a modified polycarbonate having a modified polymer skeleton, a copolymer polycarbonate, or the like.
  • the (meth) acrylic resin is a resin containing a compound having a (meth) acryloyl group as a main constituent monomer.
  • Specific examples of the (meth) acrylic resin 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-acrylate ester- (meth) acrylic acid copolymer; (meth) methyl acrylate-styrene copolymer (MS resin, etc.); methyl methacrylate and alicyclic hydrocarbon group And a copolymer with the compound (for example, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate- (meth) acrylate norbornyl copolymer, etc.).
  • 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 used as a main component (50 to 100). % Methyl methacrylate-based resin is used.
  • a surface treatment layer such as a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, and an antifouling layer is provided on the surface of the first protective film 10 opposite to the iodine-based polarizer 5. It can also be formed.
  • the method for forming the surface treatment layer is not particularly limited, and a known method can be used.
  • the first protective film 10 may contain one or more additives such as a lubricant, a plasticizer, a dispersant, a heat stabilizer, an ultraviolet absorber, an infrared absorber, an antistatic agent, and an antioxidant. it can.
  • the thickness of the first protective film 10 is preferably 90 ⁇ m or less, more preferably 50 ⁇ m or less, and even more preferably 30 ⁇ m or less, from the viewpoint of thinning the polarizing plate with a double-sided protective film.
  • the thickness of the 1st protective film 10 is 5 micrometers or more normally from a viewpoint of intensity
  • the first adhesive layer 15 is a layer for bonding and fixing the first protective film 10 to one surface of the iodine-based polarizer 5.
  • the adhesive that forms the first adhesive layer 15 is an active energy ray-curable adhesive (preferably containing a curable compound that is cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays).
  • active energy ray-curable adhesive preferably containing a curable compound that is cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays.
  • the curable compound can be a cationic polymerizable curable compound or a radical polymerizable curable compound.
  • the cationic polymerizable curable compound include an epoxy compound (a compound having one or more epoxy groups in the molecule) and an oxetane compound (one or two or more oxetane rings in the molecule). Or a combination thereof.
  • the radical polymerizable curable compound include (meth) acrylic compounds (compounds having one or more (meth) acryloyloxy groups in the molecule) and radical polymerizable double bonds. Other vinyl compounds or combinations thereof can be mentioned.
  • a cationic polymerizable curable compound and a radical polymerizable curable compound may be used in combination.
  • the active energy ray-curable adhesive usually further includes a cationic polymerization initiator and / or a radical polymerization initiator for initiating a curing reaction of the curable compound.
  • the polarizing plate 100 with a single-sided protective film may be prepared in advance or manufactured by any method. The following can be mentioned as a manufacturing method.
  • Resin layer forming step S10-1 for 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, followed by drying.
  • Stretching step S10-2 for stretching a laminated film to obtain a stretched film
  • Dyeing step S10-3 for dyeing the polyvinyl alcohol resin layer of the stretched film with iodine to form an iodine polarizer to obtain a polarizing laminated film
  • a bonding step S10-4 for obtaining a multilayer film by laminating the first protective film 10 on the iodine-based polarizer of the polarizing laminated film, and a polarizing plate with a single-side protective film by peeling and removing the base film from the multilayer film Peeling step S10-5 to obtain 100.
  • this step is a step of obtaining laminated film 200 by forming polyvinyl alcohol-based resin layer 6 on at least one surface of base film 30.
  • the polyvinyl alcohol resin layer 6 is a layer that becomes the iodine polarizer 5 through the stretching step S10-2 and the dyeing step S10-3.
  • the polyvinyl alcohol-based resin layer 6 can be formed by applying a coating liquid containing a polyvinyl alcohol-based resin to one or both surfaces of the base film 30 and drying it.
  • the method of forming the polyvinyl alcohol-based resin layer by such coating is advantageous in that a thin film iodine-based polarizer 5 can be easily obtained.
  • the base film 30 can be composed of a thermoplastic resin, and 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; System resins; and mixtures and copolymers thereof.
  • the base film 30 may have a single-layer structure made of one resin layer made of one kind or two or more kinds of thermoplastic resins, or a plurality of resin layers made of one kind or two or more kinds of thermoplastic resins. A laminated multilayer structure may be used.
  • the base film 30 is preferably made of a resin that can be stretched at a stretching temperature suitable for stretching the polyvinyl alcohol-based resin layer 6 in the stretching step S10-2 described later.
  • the base film 30 can contain an additive.
  • the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, an anti-coloring agent, a flame retardant, a nucleating agent, an antistatic agent, a pigment, and a coloring agent.
  • the thickness of the base film 30 is usually 1 to 500 ⁇ m, preferably 1 to 300 ⁇ m, more preferably 5 to 200 ⁇ m, and still more preferably 5 to 150 ⁇ m from the viewpoints of strength and handleability.
  • the coating liquid applied to the base film 30 is preferably a polyvinyl alcohol resin solution obtained by dissolving a polyvinyl alcohol resin powder in a good solvent (for example, water).
  • a good solvent for example, water
  • the details of the polyvinyl alcohol resin are as described above.
  • the coating liquid may contain additives such as a plasticizer and a surfactant as necessary.
  • the coating liquid is applied to the base film 30 by a wire bar coating method; a roll coating method such as reverse coating or gravure coating; a die coating method; a comma coating method; a lip coating method; a spin coating method;
  • the method can be appropriately selected from a method such as a fountain coating method, a dipping method, and a spray method.
  • 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 polyvinyl alcohol-based resin layer 6 may be formed only on one side of the base film 30 or on both sides. When formed on both sides, curling of the film that may occur during the production of the polarizing laminated film 400 (see FIG. 6) can be suppressed, and two polarizing plates can be obtained from one polarizing laminated film 400. It is also advantageous in terms of efficiency.
  • the thickness of the polyvinyl alcohol-based resin layer 6 in the laminated film 200 is preferably 3 to 30 ⁇ m, and more preferably 5 to 20 ⁇ m. If the polyvinyl alcohol-based resin layer 6 has a thickness within this range, it passes through the stretching step S10-2 and the dyeing step S10-3, which will be described later, and has good iodine dyeability, excellent polarization performance, and is sufficiently thin ( For example, an iodine-based polarizer 5 having a thickness of 10 ⁇ m or less can be obtained.
  • At least the surface of the base film 30 on the side where the polyvinyl alcohol resin layer 6 is formed is provided. Corona treatment, plasma treatment, flame (flame) treatment or the like may be performed. For the same reason, the polyvinyl alcohol-based resin layer 6 may be formed on the base film 30 via a primer layer or the like.
  • the primer layer can be formed by applying a primer layer forming coating solution onto the surface of the base film 30 and then drying it.
  • This coating solution includes a component that exhibits a certain degree of strong adhesion to both the base film 30 and the polyvinyl alcohol-based resin layer 6, and usually includes a resin component that provides such adhesion and a solvent.
  • a resin component 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. More preferably, it is a polyvinyl alcohol resin.
  • As the solvent a general organic solvent or an aqueous solvent capable of dissolving the resin component is usually used, but it is preferable to form the primer layer from a coating solution containing water as a solvent.
  • a crosslinking agent may be added to the primer layer forming coating solution.
  • the crosslinking agent include epoxy-based, isocyanate-based, dialdehyde-based, metal-based (for example, metal salts, metal oxides, metal hydroxides, organometallic compounds), and polymer-based crosslinking agents.
  • a polyvinyl alcohol resin is used as the resin component for forming the primer layer
  • a polyamide epoxy resin, a methylolated melamine resin, a dialdehyde crosslinking agent, a metal chelate compound crosslinking agent, or the like is preferably used.
  • the thickness of the primer layer is preferably about 0.05 to 1 ⁇ m, 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 30 and the polyvinyl alcohol-based resin layer 6 is small, and when the thickness is more than 1 ⁇ m, it is disadvantageous for thinning the polarizing plate with a double-sided protective film.
  • the method of applying the primer layer forming coating solution to the base film 30 can be the same as the coating solution for forming the polyvinyl alcohol-based resin layer.
  • the drying temperature of the coating layer made of the primer layer forming coating solution is, for example, 50 to 200 ° C., and preferably 60 to 150 ° C. When the solvent contains water, the drying temperature is preferably 80 ° C. or higher.
  • this process is a process of extending the laminated film 200 to obtain a stretched film 300 composed of the stretched base film 30 ′ and the polyvinyl alcohol-based resin layer 6 ′.
  • the stretching process is usually uniaxial stretching.
  • the draw ratio of the laminated film 200 can be appropriately selected according to the desired polarization characteristics, but is preferably more than 5 times and not more than 17 times, more preferably more than 5 times the original length of the laminated film 200. 8 times or less.
  • the draw ratio is 5 times or less, the polyvinyl alcohol resin layer 6 ′ is not sufficiently oriented, and the degree of polarization of the iodine polarizer 5 may not be sufficiently high.
  • the draw ratio exceeds 17 times, the film is likely to be broken during stretching, and the thickness of the stretched film 300 becomes unnecessarily thin, and the workability and handleability in subsequent processes may be reduced.
  • the stretching process is not limited to one-stage stretching, and can be performed in multiple stages.
  • all of the multi-stage stretching processes may be performed continuously before the dyeing step S10-3, or the second and subsequent stretching processes may be performed as a dyeing process and / or a crosslinking process in the dyeing process S10-3. You may do it at the same time.
  • the stretching treatment may be longitudinal stretching that extends in the film longitudinal direction (film transport direction), and may be lateral stretching or oblique stretching that extends in the film width direction.
  • Examples of the longitudinal stretching method include inter-roll stretching using a roll, compression stretching, stretching using a chuck (clip), and the like, and examples of the lateral stretching method include a tenter method.
  • As the stretching treatment either a wet stretching method or a dry stretching method can be adopted.
  • the stretching temperature is set to be equal to or higher than the temperature at which the polyvinyl alcohol-based resin layer 6 and the entire base film 30 can be stretched, and preferably the phase transition temperature (melting point or glass transition temperature) of the base film 30. It is in the range of ⁇ 30 ° C. to + 30 ° C., more preferably in the range of ⁇ 30 ° C. to + 5 ° C., and still more preferably in the range of ⁇ 25 ° C. to + 0 ° C.
  • the phase transition temperature means the highest phase transition temperature among the phase transition temperatures exhibited by the plurality of resin layers.
  • the stretching temperature is lower than the phase transition temperature of ⁇ 30 ° C., it is difficult to achieve a high-magnification stretching of more than 5 times, or the fluidity of the base film 30 is too low and the stretching process tends to be difficult.
  • the stretching temperature exceeds + 30 ° C. of the phase transition temperature, the fluidity of the base film 30 is too large and stretching tends to be difficult. Since it is easier to achieve a high draw ratio of more than 5 times, the drawing temperature is within the above range, and more preferably 120 ° C. or higher.
  • a zone heating method for example, a method in which hot air is blown and heated in a stretching zone such as a heating furnace adjusted to a predetermined temperature
  • a heater heating method a method in which infrared heaters, halogen heaters, panel heaters and the like are installed above and below the laminated film 200 and heated by radiant heat
  • the zone heating method is preferable from the viewpoint of the uniformity of the stretching temperature.
  • a preheat treatment step for preheating the laminated film 200 may be provided.
  • the preheating method the same method as the heating method in the stretching process can be used.
  • the preheating temperature is preferably in the range of ⁇ 50 ° C. to ⁇ 0 ° C. of the stretching temperature, and more preferably in the range of ⁇ 40 ° C. to ⁇ 10 ° C. of the stretching temperature.
  • a heat setting treatment step may be provided after the stretching treatment in the stretching step S10-2.
  • the heat setting process is a process in which heat treatment is performed at a temperature equal to or higher than the crystallization temperature while maintaining the tensioned state with the end of the stretched film 300 held by a clip.
  • the crystallization of the polyvinyl alcohol-based resin layer 6 ' is promoted by this heat setting treatment.
  • the temperature of the heat setting treatment is preferably in the range of ⁇ 0 ° C. to ⁇ 80 ° C. of the stretching temperature, and more preferably in the range of ⁇ 0 ° C. to ⁇ 50 ° C. of the stretching temperature.
  • this step is a step in which the polyvinyl alcohol resin layer 6 ′ of the stretched film 300 is dyed with iodine and adsorbed and oriented to form the iodine polarizer 5.
  • a polarizing laminated film 400 in which the iodine-based polarizer 5 is laminated on one surface or both surfaces of the base film 30 ′ is obtained.
  • the dyeing step can be performed by immersing the stretched film 300 in a solution containing iodine (dyeing solution).
  • a solution containing iodine a solution in which iodine is dissolved in a solvent can be used.
  • the solvent water is generally used, but an organic solvent compatible with water may be further added.
  • the iodine concentration in the dyeing solution is preferably 0.01 to 10% by weight, more preferably 0.02 to 7% by weight.
  • iodide examples 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 1: 5 to 1: 100, more preferably 1: 6 to 1:80, by weight.
  • the temperature of the dyeing solution is preferably 10 to 60 ° C., more preferably 20 to 40 ° C.
  • the dyeing step S10-3 can be performed before the stretching step S10-2, or these steps can be performed at the same time, but it is possible to satisfactorily orient iodine adsorbed on the polyvinyl alcohol-based resin layer. It is preferable to perform the dyeing step S10-3 after performing at least some stretching treatment on the laminated film 200 so as to be able to do so.
  • the dyeing step S10-3 can include a cross-linking treatment step performed subsequent to the dyeing treatment.
  • the crosslinking treatment can be performed by immersing a dyed film in a solution (crosslinking solution) in which a crosslinking agent is dissolved in a solvent.
  • a crosslinking agent include boron compounds such as boric acid and borax, glyoxal, and glutaraldehyde. Only 1 type may be used for a crosslinking agent and it may use 2 or more types together.
  • a solvent for the crosslinking solution water can be used, but it may further contain an organic solvent compatible with water.
  • the concentration of the crosslinking agent in the crosslinking solution is preferably 1 to 20% by weight, more preferably 6 to 15% by weight.
  • the crosslinking solution can further contain iodide.
  • iodide By adding the iodide, the polarization performance in the plane of the iodine-based polarizer 5 can be made more uniform. Specific examples of iodide are the same as described above.
  • the concentration of iodide in the crosslinking solution is preferably 0.05 to 15% by weight, more preferably 0.5 to 8% by weight.
  • the temperature of the crosslinking solution is preferably 10 to 90 ° C.
  • the crosslinking treatment can be performed simultaneously with the dyeing treatment by blending a crosslinking agent in the dyeing solution. Moreover, you may perform the process immersed in a crosslinking solution 2 or more times using 2 or more types of crosslinking solutions from which a composition differs.
  • 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 washing step may be a combination of a water washing step and a washing step with an iodide solution.
  • any appropriate method such as natural drying, blow drying, and heat drying can be adopted.
  • the drying temperature is usually 20 to 95 ° C.
  • the first adhesive layer 15 is formed on the iodine-based polarizer 5 of the polarizing laminated film 400, that is, on the surface opposite to the base film 30 ′ of the iodine-based polarizer 5. It is the process of obtaining the multilayer film 500 by bonding the 1st protective film 10 through.
  • the adhesive that forms the first adhesive layer 15 is as described above.
  • the first protective film 10 is usually bonded to the both surfaces of the iodine type polarizer 5.
  • these first protective films 10 may be the same type of protective film or different types of protective films.
  • the iodine type polarizer 5 is attached to the 1st protective film 10 through the active energy ray hardening adhesive used as the 1st adhesive layer 15.
  • the adhesive layer is cured by irradiating with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays.
  • active energy rays are preferable, and as a light source in this case, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, a metal halide lamp, or the like can be used.
  • the first protective film 10 may be laminated on the iodine polarizer 5 through the aqueous adhesive and then dried by heating.
  • This step is a step of peeling and removing the base film 30 ′ from the multilayer film 500. Through this step, the same polarizing plate 100 with a single-sided protective film as in FIG. 2 is obtained.
  • the peeling step S 50 Two polarizing plates with a single-sided protective film 100 can be obtained from one polarizing laminated film 400.
  • the method for peeling and removing the base film 30 ′ is not particularly limited, and can be peeled by the same method as the peeling step of a separator (peeling film) performed with a normal pressure-sensitive adhesive polarizing plate.
  • the substrate film 30 ′ may be peeled off immediately after the bonding step S10-4, or wound once in a roll after the bonding step S10-4, and peeled off while being unwound in the subsequent steps. May be.
  • the polarizing plate with a double-sided protective film is obtained by bonding the 2nd protective film 20 to the outer surface of the iodine type polarizer 5 in the polarizing plate 100 with a single-sided protective film.
  • An example of the layer structure of the polarizing plate with a double-sided protective film is shown in FIG.
  • the second protective film 20 is usually bonded (adhered and fixed) to the iodine-based polarizer 5 via the second adhesive layer 25.
  • the outer surface of the iodine-based polarizer 5 means a surface of the iodine-based polarizer 5 opposite to the first protective film 10, and a polarizing plate 100 with a single-sided protective film through a step of peeling and removing the base film 30 ′. Means the surface of the iodine-based polarizer 5 exposed by peeling off the base film 30 ′.
  • the second protective film 20 similarly to the first protective film 10, having a light transmitting property (a preferably optically clear) a thermoplastic resin, and moisture permeability by the following film 150 g / m 2/24 hr or is there.
  • a protective film having both optical functions such as a retardation film and a brightness enhancement film may be used.
  • the surface treatment layer that the second protective film 20 may have and the thickness, material, and the like of the film the above description of the first protective film 10 is cited.
  • the first protective film 10 and the second protective film 20 may be protective films made of the same kind of resin or may be protective films made of different kinds of resins.
  • the adhesive forming the second adhesive layer 25 can be an active energy ray curable adhesive or an aqueous adhesive, like the first adhesive layer 15, but preferably an ultraviolet curable adhesive or the like. It is an active energy ray-curable adhesive.
  • moisture is supplied to the iodine-based polarizer 5, so that the moisture content of the iodine-based polarizer 5 when the second protective film 20 is bonded may not be less than 8% by weight. is there.
  • the adhesive forming the second adhesive layer 25 may have the same composition as the adhesive forming the first adhesive layer 15, or may have a different composition.
  • Moisture content reduction step S30 The manufacturing method of the polarizing plate with a double-sided protective film according to the present invention is as described above so that the moisture content of the iodine-based polarizer 5 when the second protective film 20 is bonded is less than 8% by weight.
  • a moisture content reducing step S30 is performed at any one or more stages before the polarizing plate-preparing step with a double-sided protective film S20.
  • the moisture content reduction step S ⁇ b> 30 is a step of performing a process of reducing the moisture content of the iodine polarizer 5 on the film including the iodine polarizer 5.
  • An example of the timing at which the moisture content reduction step S30 is performed is as follows. 1) After sticking the 1st protective film 10 on the single side
  • the moisture content reducing step S30 is preferably performed at a stage where the surface of the iodine-based polarizer 5 is exposed, for example, before the bonding step S10-4 or after the peeling step S10-5. .
  • the moisture content reduction step S30 and the polarizing plate with a double-sided protective film are produced.
  • the moisture content reduction step S30 may be performed again during this interval.
  • a moisture absorption suppressing means after finishing a method involving temporarily pasting a peelable moisture-proof film on the exposed surface of the iodine-based polarizer 5 or a process involving forming a film including the iodine-based polarizer 5 having an exposed surface.
  • Examples include a method of winding a film in a roll shape as soon as possible to suppress the entry of moisture from the outside, and a method of further packing the roll film with a moisture-proof film such as an aluminum laminate.
  • the method of winding in a roll shape is particularly advantageous when the film to be wound has a base film, and the base film has a low moisture permeability.
  • the polarizing plate with a double-sided protective film is produced before moisture content becomes 8% by weight or more due to moisture absorption.
  • the process may be designed so that
  • the moisture content reduction step S30 takes into account 8 in consideration of the moisture absorption rate of the iodine-based polarizer 5.
  • the moisture content may be lowered sufficiently lower than the weight%.
  • the moisture content when bonding the 2nd protective film 20 is less than 8 weight%, without taking a special means between moisture content reduction process S30 and polarizing plate preparation process S20 with a double-sided protective film. It is possible to
  • a water-based adhesive can be used for laminating the iodine-based polarizer 5 and the first protective film 10, but when the water-based adhesive is used, moisture is supplied to the iodine-based polarizer 5. Therefore, it is preferable to perform the moisture content reduction step S30 after the first protective film 10 is bonded and before the second protective film 20 is bonded. In addition, this moisture content reduction process S30 does not need to be the first moisture content reduction process S30.
  • the moisture content of the iodine-based polarizer 5 when the second protective film 20 is bonded is preferably less than 6% by weight, and more preferably 5% by weight or less.
  • the specific method for reducing the moisture content is not particularly limited. For example, a method of blowing dry air, a method of passing through a humidity control zone adjusted to low humidity, a method of passing through a hot air drying furnace, an infrared heater, etc. And a method of heating using a simple heating device, and combinations thereof.
  • the polarizing plate with a double-sided protective film includes an iodine-based polarizer 5, a first protective film 10 laminated on one surface thereof, and a first laminated film on the other surface. 2 protective film 20.
  • the 1st protective film 10 and the 2nd protective film 20 are bonded (adhesion fixation) to the iodine type polarizer 5 through the 1st adhesive bond layer 15 and the 2nd adhesive bond layer 25, respectively.
  • the moisture content of the iodine polarizer 5 is less than 8% by weight, preferably less than 6% by weight, and more preferably 5% by weight or less.
  • the first protective film 10 and the second protective film 20 both moisture permeability 150 g / m 2/24 hr or less, preferably 100 g / m 2/24 hr or less of the thermoplastic resin film is used.
  • the above description is cited for specific configurations of the iodine-based polarizer 5, the first protective film 10, and the second protective film 20.
  • the polarizing plate with a double-sided protective film according to the present invention can be preferably produced by the method described above.
  • the polarizing plate with a double-sided protective film according to the present invention has a moisture content of less than 8% by weight of the iodine-based polarizer 5 and is laminated with a low moisture-permeable protective film on both surfaces. Even when the thickness of the film is small (for example, 10 ⁇ m or less in thickness), it has both heat and moisture resistance.
  • the polarizing plate with a double-sided protective film can be suitably applied to an image display device such as a liquid crystal display device or an organic EL device.
  • the polarizing plate with a double-sided protective film When applied to a liquid crystal display device, the polarizing plate with a double-sided protective film according to the present invention may be a polarizing plate disposed on the front (viewing) side of the liquid crystal cell, or disposed on the back (backlight) side. It may be a polarizing plate.
  • the polarizing plate with a double-sided protective film is a pressure-sensitive adhesive layer that is laminated on the first protective film 10 or the second protective film 20 and is bonded to another member (for example, a liquid crystal cell when applied to a liquid crystal display device). May be provided.
  • the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is usually based on a (meth) 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 is added thereto. It consists of an adhesive composition. Furthermore, it can also be set as the adhesive layer which contains microparticles
  • the thickness of the pressure-sensitive adhesive layer is usually 1 to 40 ⁇ m, preferably 3 to 25 ⁇ m.
  • the polarizing plate with a double-sided protective film can further include another optical layer laminated on the first protective film 10 or the second protective film 20.
  • a reflective polarizing film that transmits a certain kind of polarized light and reflects polarized light that exhibits the opposite properties
  • a film with an antiglare function having a concavo-convex 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
  • a viewing angle compensation film is another optical layer laminated on the first protective film 10 or the second protective film 20.
  • Example 1 (1) Primer layer forming step Polyvinyl alcohol powder (“Z-200” manufactured by Nippon Synthetic Chemical Industry Co., Ltd., average polymerization degree 1100, saponification degree 99.5 mol%) was dissolved in 95 ° C. hot water, A polyvinyl alcohol aqueous solution having a concentration of 3% by weight was prepared. The resulting aqueous solution was mixed with a crosslinking agent (“Smiles Resin 650” manufactured by Taoka Chemical Co., Ltd.) at a ratio of 5 parts by weight to 6 parts by weight of the polyvinyl alcohol powder to form a primer layer forming coating solution. Got.
  • a crosslinking agent (“Smiles Resin 650” manufactured by Taoka Chemical Co., Ltd.)
  • the substrate film having a thickness of 90 ⁇ m made of polypropylene (melting point: 163 ° C., moisture permeability: 15g / m 2 / 24hr) was subjected to corona treatment on one surface of, using a small-diameter gravure coater on the corona-treated surface above
  • the primer layer-forming coating solution was applied and dried at 80 ° C. for 10 minutes to form a primer layer having a thickness of 0.2 ⁇ m.
  • a crosslinking treatment was performed by immersing in a crosslinking aqueous solution (containing 5.7 parts by weight of boric acid and 12 parts by weight of potassium iodide per 100 parts by weight of water) for 60 seconds. Thereafter, it was washed with pure water at 10 ° C. for 10 seconds. Finally, it was dried at 50 ° C. for 60 seconds and then at 80 ° C.
  • a polarizing laminated film composed of a base film / iodine polarizer.
  • the moisture content of the iodine-type polarizer of the polarizing laminated film at the end of drying was 0.4% by weight.
  • the iodine polarizer had a thickness of 5.6 ⁇ m.
  • the surface of the iodine polarizer opposite to the base film has removability so that moisture content in the air can be absorbed and moisture content of the iodine polarizer can be suppressed.
  • the low moisture resistance film polyolefin resin film of moisture permeability 30g / m 2 / 24hr
  • the first protective film was bonded to the peeled surface.
  • the first protective film the moisture permeability is 16g / m 2 / 24hr, using thermoplastic resin film 23 ⁇ m thick made of cyclic polyolefin resin (Nippon Zeon's "ZF-14").
  • the first protective film is bonded using a small-diameter gravure coater so that the thickness after curing the ultraviolet curable adhesive (“KR-75T” manufactured by ADEKA Co., Ltd.) on the one side is about 1.0 ⁇ m.
  • this is bonded to the release surface using a bonding roll, and then irradiated with ultraviolet light with a cumulative amount of 200 mJ / cm 2 from the base film side using a high-pressure mercury lamp and bonded. This was done by curing the agent layer.
  • polarizing plate with double-sided protective film peeling step and polarizing plate with double-sided protective film
  • peeling step and polarizing plate with double-sided protective film Immediately after peeling the base film from the multilayer film produced in (5) above, a second protective film is bonded to the peeled surface, and the first protective film / adhesive layer / iodine polarizer / adhesive.
  • a polarizing plate with a double-sided protective film comprising a layer / second protective film was obtained.
  • the second protective film, the moisture permeability is 16g / m 2 / 24hr, using thermoplastic resin film 23 ⁇ m thick made of cyclic polyolefin resin (Nippon Zeon's "ZF-14").
  • the second protective film is bonded using a small-diameter gravure coater so that the thickness after curing the ultraviolet curable adhesive (“KR-75T” manufactured by ADEKA Co., Ltd.) is about 1.0 ⁇ m on one side. After coating, this is bonded to the release surface using a bonding roll, and then irradiated with ultraviolet light with an integrated light amount of 200 mJ / cm 2 from the second protective film side using a high-pressure mercury lamp. This was done by curing the adhesive layer. The moisture content of the iodine-type polarizer when bonding the second protective film was 0.5% by weight.
  • Example 2 A polarizing plate with a double-sided protective film was produced in the same manner as in Example 1, except that the final drying treatment (moisture content reduction step) was performed at 50 ° C. for 60 seconds and then at 65 ° C. for 60 seconds. .
  • the moisture content of the iodine-based polarizer when the second protective film was bonded was 4.6% by weight.
  • Example 3 In the same manner as in Example 2, a polarizing plate with a double-sided protective film was produced.
  • the moisture content of the iodine-based polarizer when the second protective film is bonded is 4.4% by weight, and the visibility correction polarization degree Py of the polarizing plate with a double-sided protection film is 99.995%, and the visibility correction single transmission is performed.
  • the rate Ty was 40.9%.
  • the moisture permeability is 63 g / m 2/24 hr or, using a thermoplastic resin film having a thickness of 80 ⁇ m made of an acrylic resin, an ultraviolet curable adhesive ((Ltd.) ADEKA manufactured A polarizing plate with a double-sided protective film was produced in the same manner as in Example 2 except that “KR-15P”) was used.
  • the moisture content of the iodine-based polarizer is 4.2% by weight
  • the visibility correction polarization degree Py of the polarizing plate with a double-sided protection film is 99.994%
  • the visibility correction single transmission was 41.4%.
  • the first protective film uses an ultraviolet curable adhesive (“KR-15P” manufactured by ADEKA), and the second protective film uses “KR-75T” manufactured by an ultraviolet curable adhesive ADEKA.
  • Example 2 Except having used, it carried out similarly to Example 2, and produced the polarizing plate with a double-sided protective film.
  • the moisture content of the iodine-based polarizer is 4.8% by weight, and the visibility correction polarization degree Py of the polarizing plate with the double-sided protection film is 99.994%, and the visibility correction single transmission.
  • the rate Ty was 41.4%.
  • Example 1 A polarizing plate with a double-sided protective film was produced in the same manner as in Example 1 except that the final drying treatment (moisture content reduction step) was performed at 40 ° C. for 60 seconds and then at 50 ° C. for 60 seconds. .
  • the moisture content of the iodine-type polarizer when bonding the second protective film was 10.7% by weight.
  • ⁇ Comparative example 2> A polarizing plate with a double-sided protective film was produced in the same manner as in Example 1 except that the final drying treatment (moisture content reduction step) was performed at 40 ° C. for 120 seconds. The moisture content of the iodine-type polarizer when bonding the second protective film was 12.5% by weight.
  • the moisture permeability of the films and the moisture content of the iodine polarizer were measured by the following methods.
  • Moisture Permeability Moisture permeability at a temperature of 40 ° C. and a relative humidity of 90% was measured according to JIS Z 0208-1976 “Method of testing moisture permeability of moisture-proof packaging material (cup method)”.
  • Moisture content of iodine-based polarizer The relationship between the moisture content measured by a near-infrared moisture meter ("IRMA1100S" manufactured by Chino Co., Ltd.) and the moisture content obtained by the dry weight method is a linear expression. A calibration curve to be expressed is obtained in advance from both moisture percentages obtained for a plurality of iodine-based polarizer samples having different moisture percentages, and the moisture percentage measured by a near-infrared moisture percentage meter is measured by the dry weight method using the calibration curve. In terms of the moisture content by the above, this was used as the moisture content of the iodine polarizer.
  • the degree of light leakage was visually confirmed for the polarizing plate with a double-sided protective film after the heat resistance test. Specifically, two sample pieces of 10 cm ⁇ 20 cm were cut out from the polarizing plate with a double-sided protective film after the heat resistance test, and these samples were bonded to both surfaces of the glass plate using an adhesive. At this time, the second protective film side was set to the glass plate side, and the sample pieces arranged on both surfaces were set to have a crossed Nicols positional relationship. And the backlight was applied from the one polarizing plate side in the dark room, and the visual evaluation of red discoloration was performed according to the following evaluation criteria. The results are shown in Tables 1 and 2.
  • A The black state is maintained and redness cannot be recognized visually.
  • B Clear red discoloration is observed.

Abstract

A method for producing a polarizing plate having protective films on both surfaces thereof, which comprises: a step for separating and removing a base film from a multilayer film that comprises the base film, an iodine-based polarizer and a first protective film in this order; and a step for bonding a second protective film on the outer surface of the iodine-based polarizer. The first and second protective films are composed of a thermoplastic resin film having a water vapor permeability of 150 g/m2/24 hr or less. The moisture percentage of the iodine-based polarizer when the second protective film is bonded thereto is less than 8% by weight. Also provided is a polarizing plate having protective films on both surfaces thereof, which is obtained by laminating thermoplastic resin films having a water vapor permeability of 150 g/m2/24 hr or less on both surfaces of an iodine-based polarizer that has a moisture percentage of less than 8% by weight.

Description

両面保護フィルム付偏光板の製造方法Manufacturing method of polarizing plate with double-sided protective film
 本発明は、ヨウ素系偏光子の両面に保護フィルムを貼合した両面保護フィルム付偏光板の製造方法に関し、より詳しくは、ヨウ素系偏光子の両面に透湿度の低い保護フィルムを逐次的に貼合して両面保護フィルム付偏光板を製造する方法に関する。 The present invention relates to a method for producing a polarizing plate with a double-sided protective film in which protective films are bonded to both surfaces of an iodine-based polarizer, and more specifically, a protective film having a low moisture permeability is sequentially bonded to both surfaces of an iodine-based polarizer. The present invention relates to a method for producing a polarizing plate with a double-sided protective film.
 偏光板は、液晶表示装置等の表示装置、とりわけ近年ではスマートフォンのような各種モバイル機器に広く用いられている。偏光板としては、偏光子の片面又は両面に、接着剤を用いて保護フィルムを貼合した構成のものが一般的である。 The polarizing plate has been widely used in display devices such as liquid crystal display devices, especially in recent years for various mobile devices such as smartphones. As a polarizing plate, the thing of the structure which bonded the protective film on the single side | surface or both surfaces of the polarizer using the adhesive agent is common.
 偏光子それ自体は、耐湿熱性が低く、湿熱環境下で偏光特性が劣化しやすい。従来、偏光子を保護する保護フィルムにはトリアセチルセルロースフィルムが用いられてきたが、トリアセチルセルロースフィルムは透湿度が高いため、これを保護フィルムに用いた偏光板は、特に偏光子としてヨウ素系偏光子を使用する場合において耐湿熱性がなお十分でないという問題があった。 The polarizer itself has low heat and humidity resistance, and its polarization characteristics are likely to deteriorate in a wet and heat environment. Conventionally, a triacetyl cellulose film has been used as a protective film for protecting a polarizer, but since a triacetyl cellulose film has high moisture permeability, a polarizing plate using this film as a protective film is particularly iodine-based as a polarizer. In the case of using a polarizer, there has been a problem that the heat and humidity resistance is still insufficient.
 そこで、偏光板の耐湿熱性を改善するために、トリアセチルセルロースフィルムに代えて、例えばノルボルネン系樹脂フィルムのような透湿度の低い保護フィルムをヨウ素系偏光子に貼合することが提案されている〔例えば、特開2004-245925号公報(特許文献1)の段落[0005]〕。 Therefore, in order to improve the moisture and heat resistance of the polarizing plate, it has been proposed to bond a protective film having a low moisture permeability such as a norbornene resin film to the iodine polarizer instead of the triacetyl cellulose film. [For example, paragraph [0005] of JP-A-2004-245925 (Patent Document 1)].
特開2004-245925号公報JP 2004-245925 A
 透湿度の低い保護フィルムをヨウ素系偏光子の両面に貼合すれば、外部からの水分の侵入が低減されるため、偏光板の耐湿熱性を高めることができる。しかしながらその一方で、このような透湿度の低い保護フィルムを両面に用いた従来の両面保護フィルム付偏光板は、一般の耐湿熱性試験よりも高い温度環境下に晒す耐熱性試験を実施すると、クロスニコル下での光漏れ(退色して偏光板から赤色領域の光が漏れて偏光板が赤く見える現象。赤変ともいう。)が生じたり、偏光特性が低下したりすることが本発明者の検討により明らかとなった。この耐熱性不良の問題は、ヨウ素系偏光子の厚みが小さいほど顕著である。 If a protective film with low moisture permeability is bonded to both sides of the iodine polarizer, moisture penetration from the outside is reduced, so that the moisture and heat resistance of the polarizing plate can be improved. However, on the other hand, a conventional polarizing plate with a double-sided protective film using a protective film with low moisture permeability on both sides is cross-linked when subjected to a heat resistance test that is exposed to a higher temperature environment than a general wet heat resistance test. It is the inventor of the present invention that light leakage occurs under Nicol (a phenomenon in which red color light leaks from the polarizing plate and the polarizing plate appears red, also referred to as red discoloration), or polarization characteristics deteriorate. It became clear by examination. This problem of poor heat resistance becomes more conspicuous as the thickness of the iodine polarizer is smaller.
 そこで本発明は、ヨウ素系偏光子の両面に透湿性の低い保護フィルムを貼合した偏光板であって、耐湿熱性と耐熱性とを兼備する両面保護フィルム付偏光板を製造するための方法、及び耐湿熱性と耐熱性とを兼備する両面保護フィルム付偏光板の提供を目的とする。 Therefore, the present invention is a polarizing plate in which a protective film having low moisture permeability is bonded to both surfaces of an iodine-based polarizer, and a method for producing a polarizing plate with a double-sided protective film that combines heat and moisture resistance, And it aims at provision of the polarizing plate with a double-sided protective film which combines heat-and-moisture resistance and heat resistance.
 本発明は、以下に示す両面保護フィルム付偏光板の製造方法、及び両面保護フィルム付偏光板を提供する。 This invention provides the manufacturing method of the polarizing plate with a double-sided protective film shown below, and the polarizing plate with a double-sided protective film.
 [1]基材フィルム、ヨウ素系偏光子及び第1保護フィルムをこの順で含む多層フィルムから基材フィルムを剥離除去して、片面保護フィルム付偏光板を得る工程と、
 前記片面保護フィルム付偏光板におけるヨウ素系偏光子の外面に第2保護フィルムを貼合して、両面保護フィルム付偏光板を得る工程と、
を含み、
 前記第1保護フィルム及び前記第2保護フィルムは、透湿度150g/m2/24hr以下の熱可塑性樹脂フィルムであり、
 前記第2保護フィルムを貼合するときの前記ヨウ素系偏光子の水分率が8重量%未満である、両面保護フィルム付偏光板の製造方法。
[1] A step of peeling and removing the base film from the multilayer film including the base film, the iodine-based polarizer and the first protective film in this order to obtain a polarizing plate with a single-side protective film;
Bonding a second protective film to the outer surface of the iodine-based polarizer in the polarizing plate with a single-sided protective film to obtain a polarizing plate with a double-sided protective film;
Including
The first protective film and the second protective film is a thermoplastic film of less moisture permeability 150 g / m 2/24 hr or,
The manufacturing method of the polarizing plate with a double-sided protective film whose moisture content of the said iodine type polarizer when bonding a said 2nd protective film is less than 8 weight%.
 [2]活性エネルギー線硬化性接着剤を用いて前記第2保護フィルムを前記ヨウ素系偏光子の外面に貼合する、[1]に記載の製造方法。 [2] The production method according to [1], wherein the second protective film is bonded to the outer surface of the iodine polarizer using an active energy ray-curable adhesive.
 [3]前記ヨウ素系偏光子は、その厚みが10μm以下である、[1]又は[2]に記載の製造方法。 [3] The manufacturing method according to [1] or [2], wherein the iodine polarizer has a thickness of 10 μm or less.
 [4]ヨウ素系偏光子及びその片面に積層される第1保護フィルムを含む片面保護フィルム付偏光板におけるヨウ素系偏光子外面に第2保護フィルムを貼合して、両面保護フィルム付偏光板を得る工程を含み、
 前記第1保護フィルム及び前記第2保護フィルムは、透湿度150g/m2/24hr以下の熱可塑性樹脂フィルムであり、
 前記第2保護フィルムを貼合するときの前記ヨウ素系偏光子の水分率が8重量%未満である、両面保護フィルム付偏光板の製造方法。
[4] A polarizing plate with a double-sided protective film is obtained by laminating a second protective film on the outer surface of the iodine-type polarizer in the polarizing plate with a single-sided protective film including the iodine-type polarizer and the first protective film laminated on one side thereof. Including a step of obtaining
The first protective film and the second protective film is a thermoplastic film of less moisture permeability 150 g / m 2/24 hr or,
The manufacturing method of the polarizing plate with a double-sided protective film whose moisture content of the said iodine type polarizer when bonding a said 2nd protective film is less than 8 weight%.
 [5]活性エネルギー線硬化性接着剤を用いて前記第2保護フィルムを前記ヨウ素系偏光子の外面に貼合する、[4]に記載の製造方法。 [5] The production method according to [4], wherein the second protective film is bonded to the outer surface of the iodine polarizer using an active energy ray-curable adhesive.
 [6]前記ヨウ素系偏光子は、その厚みが10μm以下である、[4]又は[5]に記載の製造方法。 [6] The manufacturing method according to [4] or [5], wherein the iodine polarizer has a thickness of 10 μm or less.
 [7]ヨウ素系偏光子とその両面に積層される保護フィルムとを含み、
 両面に積層される保護フィルムはいずれも、透湿度150g/m2/24hr以下の熱可塑性樹脂フィルムであり、
 前記ヨウ素系偏光子の水分率が8重量%未満である、両面保護フィルム付偏光板。
[7] An iodine-based polarizer and a protective film laminated on both sides thereof,
Any protective film to be laminated on both sides, a thermoplastic resin film of less moisture permeability 150g / m 2 / 24hr,
A polarizing plate with a double-sided protective film, wherein the iodine polarizer has a moisture content of less than 8% by weight.
 [8]前記ヨウ素系偏光子は、その厚みが10μm以下である、[7]に記載の両面保護フィルム付偏光板。 [8] The polarizing plate with a double-sided protective film according to [7], wherein the iodine-based polarizer has a thickness of 10 μm or less.
 本発明によれば、ヨウ素系偏光子の両面に透湿性の低い保護フィルムを貼合した偏光板であって、耐湿熱性と耐熱性とを兼備する両面保護フィルム付偏光板を製造するための方法、及び、ヨウ素系偏光子の両面に透湿性の低い保護フィルムを貼合した偏光板であって、耐湿熱性と耐熱性とを兼備する両面保護フィルム付偏光板を提供することができる。 According to the present invention, a method for producing a polarizing plate with a double-sided protective film, which is a polarizing plate in which a protective film having low moisture permeability is bonded to both sides of an iodine-based polarizer, which has both moisture heat resistance and heat resistance. And the polarizing plate which bonded the protective film with low moisture permeability on both surfaces of an iodine type polarizer, Comprising: The polarizing plate with a double-sided protective film which has both heat-and-moisture resistance and heat resistance can be provided.
本発明に係る両面保護フィルム付偏光板の製造方法の好ましい一例を示すフローチャートである。It is a flowchart which shows a preferable example of the manufacturing method of the polarizing plate with a double-sided protective film which concerns on this invention. 片面保護フィルム付偏光板の層構成の一例を示す概略断面図である。It is a schematic sectional drawing which shows an example of the laminated constitution of the polarizing plate with a single-sided protective film. 片面保護フィルム付偏光板準備工程の好ましい一例を示すフローチャートである。It is a flowchart which shows a preferable example of a polarizing plate preparation process with a single-sided protective film. 樹脂層形成工程で得られる積層フィルムの層構成の一例を示す概略断面図である。It is a schematic sectional drawing which shows an example of the laminated constitution of the laminated | multilayer film obtained at a resin layer formation process. 延伸工程で得られる延伸フィルムの層構成の一例を示す概略断面図である。It is a schematic sectional drawing which shows an example of the laminated constitution of the stretched film obtained at a extending process. 染色工程で得られる偏光性積層フィルムの層構成の一例を示す概略断面図である。It is a schematic sectional drawing which shows an example of the laminated constitution of the light-polarizing laminated film obtained at a dyeing process. 貼合工程で得られる多層フィルムの層構成の一例を示す概略断面図である。It is a schematic sectional drawing which shows an example of the laminated constitution of the multilayer film obtained at a bonding process. 本発明に係る両面保護フィルム付偏光板の層構成の一例を示す概略断面図である。It is a schematic sectional drawing which shows an example of the layer structure of the polarizing plate with a double-sided protective film which concerns on this invention.
 <両面保護フィルム付偏光板の製造方法>
 本発明に係る両面保護フィルム付偏光板の製造方法は、図1に示されるとおり、下記の工程を含むものであることができる。
<Method for producing polarizing plate with double-sided protective film>
The manufacturing method of the polarizing plate with a double-sided protective film according to the present invention may include the following steps as shown in FIG.
 (1)ヨウ素系偏光子及びその片面に積層される第1保護フィルムを含む片面保護フィルム付偏光板を準備する工程S10(以下、「片面保護フィルム付偏光板準備工程S10」ともいう)、及び
 (2)片面保護フィルム付偏光板におけるヨウ素系偏光子外面に第2保護フィルムを貼合して、両面保護フィルム付偏光板を得る工程S20(以下、「両面保護フィルム付偏光板作製工程S20」ともいう)。
(1) Step S10 of preparing a polarizing plate with a single-sided protective film including an iodine-based polarizer and a first protective film laminated on one side thereof (hereinafter also referred to as “polarizing plate with a single-sided protective film S10”), and (2) Step S20 for obtaining a polarizing plate with a double-sided protective film by bonding the second protective film to the outer surface of the iodine-based polarizer in the polarizing plate with a single-sided protective film (hereinafter referred to as “Polarizer production step S20 with double-sided protective film”). Also called).
 上記のとおり本発明においては、第1保護フィルムと第2保護フィルムは、ヨウ素系偏光子に対して逐次的に貼合される。その際、得られる両面保護フィルム付偏光板の耐湿熱性を向上させるために、ヨウ素系偏光子の一方の面に貼合される第1保護フィルム及び他方の面に貼合される第2保護フィルムとして、透湿度が150g/m2/24hr以下である低透湿度の熱可塑性樹脂フィルムを用いる。 As described above, in the present invention, the first protective film and the second protective film are sequentially bonded to the iodine polarizer. In that case, in order to improve the heat-and-moisture resistance of the polarizing plate with a double-sided protective film obtained, the 1st protective film bonded to one side of an iodine type polarizer, and the 2nd protective film bonded to the other side as a moisture permeability using a thermoplastic resin film of low moisture permeability is not more than 150g / m 2 / 24hr.
 また、得られる両面保護フィルム付偏光板の耐熱性を向上させるために、ヨウ素系偏光子に第2保護フィルムを貼合するときのヨウ素系偏光子の水分率を8重量%未満とする。本発明では、耐湿熱性を向上させるために、ヨウ素系偏光子の両面に透湿度の低い保護フィルムを貼合して偏光板とするのであるが、
a)透湿度の低い保護フィルムを両面に適用すると、ヨウ素系偏光子中の水分が外部に放散されにくく、水分がヨウ素系偏光子の中にたまってしまうこと、
b)耐熱性試験における赤変や偏光特性の低下は、このヨウ素系偏光子中に残留する水分によって引き起こされること
などの状況から、上記のとおり第2保護フィルムを貼合するときのヨウ素系偏光子の水分率を管理することが有効である。ヨウ素系偏光子の水分率は、実施例の項に記載の方法に従って測定される。
Moreover, in order to improve the heat resistance of the polarizing plate with a double-sided protective film obtained, the water content of the iodine-based polarizer when the second protective film is bonded to the iodine-based polarizer is less than 8% by weight. In the present invention, in order to improve the heat and moisture resistance, a protective film with low moisture permeability is bonded to both surfaces of the iodine-based polarizer to form a polarizing plate.
a) When a protective film with low moisture permeability is applied to both sides, moisture in the iodine-based polarizer is difficult to dissipate to the outside, and moisture accumulates in the iodine-based polarizer,
b) Iodine-based polarized light when the second protective film is bonded as described above from the situation such as redness in the heat resistance test and deterioration of polarization characteristics caused by moisture remaining in the iodine-based polarizer. It is effective to control the moisture content of the child. The moisture content of the iodine-based polarizer is measured according to the method described in the Examples section.
 ヨウ素系偏光子の水分率は、両面保護フィルム付偏光板を製造する工程中であって、ヨウ素系偏光子に第2保護フィルムを貼合する前のいずれかの段階に、(3)ヨウ素系偏光子を含むフィルムに対して水分率低減処理を施す工程S30(以下、「水分率低減工程S30」ともいう)を設けることによって達成することができる(図1参照)。 The moisture content of the iodine-based polarizer is during the process of manufacturing the polarizing plate with a double-sided protective film, and is in any stage before the second protective film is bonded to the iodine-based polarizer. This can be achieved by providing a step S30 (hereinafter also referred to as “moisture percentage reduction step S30”) for performing a moisture percentage reduction process on the film including the polarizer (see FIG. 1).
 以下、図2~図8を参照しながら各工程について説明する。
 (1)片面保護フィルム付偏光板準備工程S10
 本工程は、ヨウ素系偏光子5及びその片面に積層される第1保護フィルム10を含む、例えば図2に示されるような片面保護フィルム付偏光板100を準備(用意)する工程である。図2に示されるように、第1保護フィルム10は通常、第1接着剤層15を介してヨウ素系偏光子5の片面に貼合(接着固定)される。
Hereinafter, each step will be described with reference to FIGS.
(1) Polarizing plate preparation process S10 with a single-sided protective film
This step is a step of preparing (preparing) a polarizing plate 100 with a single-sided protective film as shown in FIG. 2, for example, including the iodine-based polarizer 5 and the first protective film 10 laminated on one side thereof. As shown in FIG. 2, the first protective film 10 is usually bonded (adhered and fixed) to one surface of the iodine-based polarizer 5 via the first adhesive layer 15.
 〔ヨウ素系偏光子〕
 ヨウ素系偏光子5は、二色性色素としてヨウ素を吸着配向させた偏光子であり、具体的には、一軸延伸されたポリビニルアルコール系樹脂層(又はフィルム)にヨウ素を吸着配向させたものであることができる。ヨウ素系偏光子5の厚みは例えば30μm以下、さらには20μm以下であることができるが、とりわけモバイル機器用においては、両面保護フィルム付偏光板の薄型化の観点から10μm以下であることが好ましく、8μm以下であることがより好ましい。ヨウ素系偏光子5の厚みは通常、2μm以上である。
[Iodine polarizer]
The iodine-based polarizer 5 is a polarizer in which iodine is adsorbed and oriented as a dichroic dye. Specifically, the iodine-based polarizer 5 is obtained by adsorbing and orienting iodine to a uniaxially stretched polyvinyl alcohol resin layer (or film). Can be. The thickness of the iodine-based polarizer 5 can be, for example, 30 μm or less, and further 20 μm or less, but in particular for mobile devices, it is preferably 10 μm or less from the viewpoint of thinning the polarizing plate with a double-sided protective film, More preferably, it is 8 μm or less. The thickness of the iodine-based polarizer 5 is usually 2 μm or more.
 ヨウ素系偏光子5の厚みが小さくなると、ヨウ素の濃度がより高くなり、両面に積層される保護フィルムとの界面近傍に存在するヨウ素錯体の濃度も高くなるために、外部から侵入する水分の影響を受けやすい。従って、ヨウ素系偏光子5の厚みが小さいほど耐湿熱性は低くなりやすい。また、ヨウ素系偏光子5の厚みが小さくなってヨウ素の濃度がより高くなると、ヨウ素系偏光子中に残存する水分の影響を受けやすくなり、耐熱性も低くなりやすい。このように、ヨウ素系偏光子5の厚みが小さいほど耐湿熱性及び耐熱性が低くなりやすいところ、本発明は、ヨウ素系偏光子5の厚みが小さい場合にとりわけ有利である。 When the thickness of the iodine-based polarizer 5 is reduced, the concentration of iodine is increased, and the concentration of iodine complex existing in the vicinity of the interface with the protective film laminated on both sides is also increased. It is easy to receive. Therefore, the heat-and-moisture resistance tends to be lower as the thickness of the iodine-based polarizer 5 is smaller. Moreover, when the thickness of the iodine-type polarizer 5 is reduced and the concentration of iodine is further increased, the iodine-type polarizer 5 is easily affected by moisture remaining in the iodine-type polarizer and heat resistance is likely to be lowered. As described above, the heat-and-moisture resistance and heat resistance are likely to be lower as the thickness of the iodine-based polarizer 5 is smaller. However, the present invention is particularly advantageous when the thickness of the iodine-based polarizer 5 is small.
 ポリビニルアルコール系樹脂層を構成するポリビニルアルコール系樹脂としては、ポリ酢酸ビニル系樹脂をケン化したものを用いることができる。ポリ酢酸ビニル系樹脂としては、酢酸ビニルの単独重合体であるポリ酢酸ビニルのほか、酢酸ビニルとこれに共重合可能な他の単量体との共重合体が例示される。酢酸ビニルに共重合可能な他の単量体としては、例えば、不飽和カルボン酸類、オレフィン類、ビニルエーテル類、不飽和スルホン酸類、アンモニウム基を有する(メタ)アクリルアミド類等が挙げられる。 As the polyvinyl alcohol resin constituting the polyvinyl alcohol resin layer, a saponified polyvinyl acetate resin can be used. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth) acrylamides having an ammonium group.
 本明細書において「(メタ)アクリル」とは、アクリル及びメタクリルから選択される少なくとも一方を意味する。「(メタ)アクリロイル」などというときについても同様である。 In this specification, “(meth) acryl” means at least one selected from acrylic and methacrylic. The same applies to cases such as “(meth) acryloyl”.
 上記ポリビニルアルコール系樹脂を製膜したものがヨウ素系偏光子5を構成する。ポリビニルアルコール系樹脂を製膜する方法は特に限定されるものではなく、公知の方法で製膜することができるが、厚みの小さいヨウ素系偏光子5を得やすく、工程中における薄膜のヨウ素系偏光子5の取扱性にも優れることから、後述するようなポリビニルアルコール系樹脂の溶液を基材フィルム上に塗工して製膜する方法が好ましい。 A film obtained by forming a film of the polyvinyl alcohol resin constitutes the iodine polarizer 5. The method for forming the polyvinyl alcohol-based resin is not particularly limited, and can be formed by a known method, but it is easy to obtain the iodine-based polarizer 5 having a small thickness, and the iodine-based polarization of the thin film in the process. Since the handleability of the child 5 is also excellent, a method of forming a film by coating a solution of a polyvinyl alcohol resin as described later on the base film is preferable.
 ポリビニルアルコール系樹脂のケン化度は、80.0~100.0モル%の範囲であることができるが、好ましくは90.0~99.5モル%の範囲であり、より好ましくは94.0~99.0モル%の範囲である。ケン化度が80.0モル%未満であると、得られる両面保護フィルム付偏光板の耐水性及び耐湿熱性が低下する。ケン化度が99.5モル%を超えるポリビニルアルコール系樹脂を使用した場合、ヨウ素の染色速度が遅くなり、生産性が低下するとともに十分な偏光性能を有するヨウ素系偏光子5が得られない場合がある。 The degree of saponification of the polyvinyl alcohol-based resin can be in the range of 80.0 to 100.0 mol%, preferably in the range of 90.0 to 99.5 mol%, more preferably 94.0. It is in the range of ˜99.0 mol%. When the degree of saponification is less than 80.0 mol%, the water resistance and heat-and-moisture resistance of the resulting polarizing plate with a double-sided protective film are lowered. When a polyvinyl alcohol-based resin having a saponification degree exceeding 99.5 mol% is used, the iodine dyeing speed becomes slow, the productivity decreases, and the iodine-based polarizer 5 having sufficient polarization performance cannot be obtained. There is.
 ケン化度とは、ポリビニルアルコール系樹脂の原料であるポリ酢酸ビニル系樹脂に含まれる酢酸基(アセトキシ基:-OCOCH3)がケン化工程により水酸基に変化した割合をユニット比(モル%)で表したものであり、下記式:
 ケン化度(モル%)=100×(水酸基の数)÷(水酸基の数+酢酸基の数)
で定義される。ケン化度は、JIS K 6726-1994に準拠して求めることができる。ケン化度が高いほど、水酸基の割合が高いことを示しており、従って結晶化を阻害する酢酸基の割合が低いことを示している。
The degree of saponification is the unit ratio (mol%) of the ratio of acetate groups (acetoxy groups: —OCOCH 3 ) contained in polyvinyl acetate resin, which is a raw material for polyvinyl alcohol resins, to hydroxyl groups by the saponification process. The following formula:
Saponification degree (mol%) = 100 × (number of hydroxyl groups) ÷ (number of hydroxyl groups + number of acetate groups)
Defined by The degree of saponification can be determined according to JIS K 6726-1994. The higher the degree of saponification, the higher the proportion of hydroxyl groups, and thus the lower the proportion of acetate groups that inhibit crystallization.
 ポリビニルアルコール系樹脂は、一部が変性されている変性ポリビニルアルコールであってもよい。例えば、ポリビニルアルコール系樹脂をエチレン、プロピレン等のオレフィン;アクリル酸、メタクリル酸、クロトン酸等の不飽和カルボン酸;不飽和カルボン酸のアルキルエステル、(メタ)アクリルアミド等で変性したものが挙げられる。変性の割合は30モル%未満であることが好ましく、10%未満であることがより好ましい。30モル%を超える変性を行った場合には、ヨウ素を吸着しにくくなり、十分な偏光性能を有するヨウ素系偏光子5が得られにくい傾向がある。 The polyvinyl alcohol resin may be a modified polyvinyl alcohol partially modified. For example, polyvinyl alcohol resins modified with olefins such as ethylene and propylene; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; alkyl esters of unsaturated carboxylic acids, (meth) acrylamide, and the like. The proportion of modification is preferably less than 30 mol%, and more preferably less than 10%. When modification exceeding 30 mol% is performed, it is difficult to adsorb iodine, and it is difficult to obtain an iodine-based polarizer 5 having sufficient polarization performance.
 ポリビニルアルコール系樹脂の平均重合度は、好ましくは100~10000であり、より好ましくは1500~8000であり、さらに好ましくは2000~5000である。ポリビニルアルコール系樹脂の平均重合度もJIS K 6726-1994に準拠して求めることができる。 The average degree of polymerization of the polyvinyl alcohol-based resin is preferably 100 to 10,000, more preferably 1500 to 8000, and further preferably 2000 to 5000. The average degree of polymerization of the polyvinyl alcohol resin can also be determined according to JIS K 6726-1994.
 〔第1保護フィルム〕
 第1保護フィルム10は、透光性を有する(好ましくは光学的に透明な)熱可塑性樹脂からなり、かつ透湿度が150g/m2/24hr以下のフィルムである。透湿度は、後述する第2保護フィルムの透湿度も含めて、JIS Z 0208-1976「防湿包装材料の透湿度試験方法(カップ法)」に準拠して測定される温度40℃、相対湿度90%での透湿度である。透湿度は、好ましくは100g/m2/24hr以下である。
[First protective film]
The first protective film 10 has a light-transmitting property (preferably optically clear) a thermoplastic resin, and the moisture permeability is less film 150g / m 2 / 24hr. The moisture permeability, including the moisture permeability of the second protective film described later, is a temperature of 40 ° C. and a relative humidity of 90 measured according to JIS Z 0208-1976 “Moisture permeability test method for moisture-proof packaging materials (cup method)”. Percent moisture permeability. Moisture permeability is preferably 100g / m 2 / 24hr or less.
 第1保護フィルム10の透湿度を150g/m2/24hr以下にする手段としては、フィルムを構成する熱可塑性樹脂に透湿性が低いものを用いたり、フィルムの厚みを大きくしたり、フィルム上に透湿性の低いバリア層を設けたりすることが挙げられる。 As a means for the moisture permeability of the first protective film 10 below 150g / m 2 / 24hr, or used as moisture permeability is lower in the thermoplastic resin constituting the film, or by increasing the thickness of the film, onto the film For example, a barrier layer having low moisture permeability may be provided.
 第1保護フィルム10を構成する熱可塑性樹脂は、上記透湿度を達成できる限り特に制限されないが、透湿性が低く、第1保護フィルム10の厚みを小さくできることから、鎖状ポリオレフィン系樹脂(ポリプロピレン系樹脂等)、環状ポリオレフィン系樹脂(ノルボルネン系樹脂等)のようなポリオレフィン系樹脂;ポリエチレンテレフタレート系樹脂のようなポリエステル系樹脂;ポリカーボネート系樹脂;(メタ)アクリル系樹脂;ポリスチレン系樹脂;又はこれらの混合物、共重合物等が好ましく用いられる。 The thermoplastic resin constituting the first protective film 10 is not particularly limited as long as the above moisture permeability can be achieved. However, since the moisture permeability is low and the thickness of the first protective film 10 can be reduced, a chain polyolefin resin (polypropylene type) is used. Resins), polyolefin resins such as cyclic polyolefin resins (norbornene resins, etc.); polyester resins such as polyethylene terephthalate resins; polycarbonate resins; (meth) acrylic resins; polystyrene resins; A mixture, copolymer or the like is preferably used.
 第1保護フィルム10は、位相差フィルム、輝度向上フィルムのような光学機能を併せ持つ保護フィルムであることもできる。例えば、上記熱可塑性樹脂からなるフィルムを延伸(一軸延伸又は二軸延伸等)したり、該フィルム上に液晶層等を形成したりすることにより、任意の位相差値が付与された位相差フィルムとすることができる。 The first protective film 10 can also be a protective film having an optical function such as a retardation film and a brightness enhancement film. For example, a retardation film provided with an arbitrary retardation value by stretching a film made of the thermoplastic resin (uniaxial stretching or biaxial stretching) or by forming a liquid crystal layer or the like on the film. It can be.
 鎖状ポリオレフィン系樹脂としては、ポリエチレン樹脂、ポリプロピレン樹脂のような鎖状オレフィンの単独重合体のほか、2種以上の鎖状オレフィンからなる共重合体を挙げることができる。 Examples of the chain polyolefin resin include a homopolymer of a chain olefin such as a polyethylene resin and a polypropylene resin, and a copolymer composed of two or more chain olefins.
 環状ポリオレフィン系樹脂は、環状オレフィンを重合単位として重合される樹脂の総称である。環状ポリオレフィン系樹脂の具体例を挙げれば、環状オレフィンの開環(共)重合体、環状オレフィンの付加重合体、環状オレフィンとエチレン、プロピレンのような鎖状オレフィンとの共重合体(代表的にはランダム共重合体)、及びこれらを不飽和カルボン酸やその誘導体で変性したグラフト重合体、並びにそれらの水素化物等である。中でも、環状オレフィンとしてノルボルネンや多環ノルボルネン系モノマー等のノルボルネン系モノマーを用いたノルボルネン系樹脂が好ましく用いられる。 Cyclic polyolefin-based resin is a general term for resins that are polymerized using cyclic olefins as polymerization units. Specific examples of 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. Among these, norbornene resins using norbornene monomers such as norbornene and polycyclic norbornene monomers as cyclic olefins are preferably used.
 ポリエステル系樹脂はエステル結合を有する樹脂であり、多価カルボン酸又はその誘導体と多価アルコールとの重縮合体からなるものが一般的である。多価カルボン酸又はその誘導体としてはジカルボン酸又はその誘導体を用いることができ、例えばテレフタル酸、イソフタル酸、ジメチルテレフタレート、ナフタレンジカルボン酸ジメチル等が挙げられる。多価アルコールとしてはジオールを用いることができ、例えばエチレングリコール、プロパンジオール、ブタンジオール、ネオペンチルグリコール、シクロヘキサンジメタノール等が挙げられる。 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. As the polyvalent carboxylic acid or a derivative thereof, a dicarboxylic acid or a derivative thereof can be used, and examples thereof include terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalenedicarboxylate. A diol can be used as the polyhydric alcohol, and examples thereof include ethylene glycol, propanediol, butanediol, neopentyl glycol, and cyclohexanedimethanol.
 ポリエステル系樹脂の具体例は、ポリエチレンテレフタレート、ポリブチレンテレフタレート、ポリエチレンナフタレート、ポリブチレンナフタレート、ポリトリメチレンテレフタレート、ポリトリメチレンナフタレート、ポリシクロへキサンジメチルテレフタレート、ポリシクロヘキサンジメチルナフタレートを含む。 Specific examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethyl terephthalate, and polycyclohexanedimethyl naphthalate.
 ポリカーボネート系樹脂は、カルボナート基を介してモノマー単位が結合された重合体からなる。ポリカーボネート系樹脂は、ポリマー骨格を修飾したような変性ポリカーボネートと呼ばれる樹脂や、共重合ポリカーボネート等であってもよい。 Polycarbonate resin is made of a polymer in which monomer units are bonded via a carbonate group. The polycarbonate-based resin may be a resin called a modified polycarbonate having a modified polymer skeleton, a copolymer polycarbonate, or the like.
 (メタ)アクリル系樹脂は、(メタ)アクリロイル基を有する化合物を主な構成モノマーとする樹脂である。(メタ)アクリル系樹脂の具体例は、例えば、ポリメタクリル酸メチルのようなポリ(メタ)アクリル酸エステル;メタクリル酸メチル-(メタ)アクリル酸共重合体;メタクリル酸メチル-(メタ)アクリル酸エステル共重合体;メタクリル酸メチル-アクリル酸エステル-(メタ)アクリル酸共重合体;(メタ)アクリル酸メチル-スチレン共重合体(MS樹脂等);メタクリル酸メチルと脂環族炭化水素基を有する化合物との共重合体(例えば、メタクリル酸メチル-メタクリル酸シクロヘキシル共重合体、メタクリル酸メチル-(メタ)アクリル酸ノルボルニル共重合体等)を含む。好ましくは、ポリ(メタ)アクリル酸メチルのようなポリ(メタ)アクリル酸C1-6アルキルエステルを主成分とする重合体が用いられ、より好ましくは、メタクリル酸メチルを主成分(50~100重量%、好ましくは70~100重量%)とするメタクリル酸メチル系樹脂が用いられる。 The (meth) acrylic resin is a resin containing a compound having a (meth) acryloyl group as a main constituent monomer. Specific examples of the (meth) acrylic resin 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-acrylate ester- (meth) acrylic acid copolymer; (meth) methyl acrylate-styrene copolymer (MS resin, etc.); methyl methacrylate and alicyclic hydrocarbon group And a copolymer with the compound (for example, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate- (meth) acrylate norbornyl copolymer, etc.). Preferably, 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 used as a main component (50 to 100). % Methyl methacrylate-based resin is used.
 第1保護フィルム10におけるヨウ素系偏光子5とは反対側の表面には、ハードコート層、防眩層、反射防止層、帯電防止層、防汚層のような表面処理層(コーティング層)を形成することもできる。表面処理層を形成する方法は特に限定されず、公知の方法を用いることができる。 A surface treatment layer (coating layer) such as a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, and an antifouling layer is provided on the surface of the first protective film 10 opposite to the iodine-based polarizer 5. It can also be formed. The method for forming the surface treatment layer is not particularly limited, and a known method can be used.
 第1保護フィルム10は、滑剤、可塑剤、分散剤、熱安定剤、紫外線吸収剤、赤外線吸収剤、帯電防止剤、酸化防止剤のような添加剤を1種又は2種以上含有することができる。 The first protective film 10 may contain one or more additives such as a lubricant, a plasticizer, a dispersant, a heat stabilizer, an ultraviolet absorber, an infrared absorber, an antistatic agent, and an antioxidant. it can.
 第1保護フィルム10の厚みは、両面保護フィルム付偏光板の薄型化の観点から、好ましくは90μm以下、より好ましくは50μm以下、さらに好ましくは30μm以下である。第1保護フィルム10の厚みは、強度及び取扱性の観点から、通常5μm以上である。 The thickness of the first protective film 10 is preferably 90 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less, from the viewpoint of thinning the polarizing plate with a double-sided protective film. The thickness of the 1st protective film 10 is 5 micrometers or more normally from a viewpoint of intensity | strength and a handleability.
 〔第1接着剤層〕
 第1接着剤層15は、ヨウ素系偏光子5の一方の面に第1保護フィルム10を接着固定するための層である。第1接着剤層15を形成する接着剤としては、紫外線、可視光、電子線、X線のような活性エネルギー線の照射によって硬化する硬化性化合物を含有する活性エネルギー線硬化性接着剤(好ましくは紫外線硬化性接着剤)や、ポリビニルアルコール系樹脂のような接着剤成分を水に溶解又分散させた水系接着剤であることができる。
[First adhesive layer]
The first adhesive layer 15 is a layer for bonding and fixing the first protective film 10 to one surface of the iodine-based polarizer 5. The adhesive that forms the first adhesive layer 15 is an active energy ray-curable adhesive (preferably containing a curable compound that is cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays). Can be a water-based adhesive in which an adhesive component such as an ultraviolet curable adhesive) or a polyvinyl alcohol-based resin is dissolved or dispersed in water.
 上記硬化性化合物は、カチオン重合性の硬化性化合物やラジカル重合性の硬化性化合物であることができる。カチオン重合性の硬化性化合物としては、例えば、エポキシ系化合物(分子内に1個又は2個以上のエポキシ基を有する化合物)や、オキセタン系化合物(分子内に1個又は2個以上のオキセタン環を有する化合物)、又はこれらの組み合わせを挙げることができる。ラジカル重合性の硬化性化合物としては、例えば、(メタ)アクリル系化合物(分子内に1個又は2個以上の(メタ)アクリロイルオキシ基を有する化合物)や、ラジカル重合性の二重結合を有するその他のビニル系化合物、又はこれらの組み合わせを挙げることができる。カチオン重合性の硬化性化合物とラジカル重合性の硬化性化合物とを併用してもよい。活性エネルギー線硬化性接着剤は通常、上記硬化性化合物の硬化反応を開始させるためのカチオン重合開始剤及び/又はラジカル重合開始剤をさらに含む。 The curable compound can be a cationic polymerizable curable compound or a radical polymerizable curable compound. Examples of the cationic polymerizable curable compound include an epoxy compound (a compound having one or more epoxy groups in the molecule) and an oxetane compound (one or two or more oxetane rings in the molecule). Or a combination thereof. Examples of the radical polymerizable curable compound include (meth) acrylic compounds (compounds having one or more (meth) acryloyloxy groups in the molecule) and radical polymerizable double bonds. Other vinyl compounds or combinations thereof can be mentioned. A cationic polymerizable curable compound and a radical polymerizable curable compound may be used in combination. The active energy ray-curable adhesive usually further includes a cationic polymerization initiator and / or a radical polymerization initiator for initiating a curing reaction of the curable compound.
 片面保護フィルム付偏光板100は、あらかじめ用意されたものであってもよいし、任意の方法によって製造されたものであってもよい。製造方法としては、次のものを挙げることができる。 The polarizing plate 100 with a single-sided protective film may be prepared in advance or manufactured by any method. The following can be mentioned as a manufacturing method.
 i)公知の方法によって製造された単体(単独)フィルムからなるヨウ素系偏光子5の片面に第1保護フィルム10を貼合する方法、及び
 ii)図3に示されるような、下記の工程を含む製造方法。
i) a method of laminating the first protective film 10 on one side of an iodine-based polarizer 5 made of a single (single) film manufactured by a known method, and ii) the following steps as shown in FIG. Manufacturing method including.
 基材フィルムの少なくとも一方の面にポリビニルアルコール系樹脂を含有する塗工液を塗工した後、乾燥させることによりポリビニルアルコール系樹脂層を形成して積層フィルムを得る樹脂層形成工程S10-1、
 積層フィルムを延伸して延伸フィルムを得る延伸工程S10-2、
 延伸フィルムのポリビニルアルコール系樹脂層をヨウ素で染色してヨウ素系偏光子を形成し、偏光性積層フィルムを得る染色工程S10-3、
 偏光性積層フィルムのヨウ素系偏光子上に第1保護フィルム10を貼合して多層フィルムを得る貼合工程S10-4、及び
 多層フィルムから基材フィルムを剥離除去して片面保護フィルム付偏光板100を得る剥離工程S10-5。
Resin layer forming step S10-1 for 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, followed by drying.
Stretching step S10-2 for stretching a laminated film to obtain a stretched film,
Dyeing step S10-3 for dyeing the polyvinyl alcohol resin layer of the stretched film with iodine to form an iodine polarizer to obtain a polarizing laminated film;
A bonding step S10-4 for obtaining a multilayer film by laminating the first protective film 10 on the iodine-based polarizer of the polarizing laminated film, and a polarizing plate with a single-side protective film by peeling and removing the base film from the multilayer film Peeling step S10-5 to obtain 100.
 〔樹脂層形成工程S10-1〕
 図4を参照して本工程は、基材フィルム30の少なくとも一方の面にポリビニルアルコール系樹脂層6を形成して積層フィルム200を得る工程である。このポリビニルアルコール系樹脂層6は、延伸工程S10-2及び染色工程S10-3を経てヨウ素系偏光子5となる層である。ポリビニルアルコール系樹脂層6は、ポリビニルアルコール系樹脂を含有する塗工液を基材フィルム30の片面又は両面に塗工し、乾燥させることにより形成することができる。このような塗工によりポリビニルアルコール系樹脂層を形成する方法は、薄膜のヨウ素系偏光子5を得やすい点で有利である。
[Resin layer forming step S10-1]
Referring to FIG. 4, this step is a step of obtaining laminated film 200 by forming polyvinyl alcohol-based resin layer 6 on at least one surface of base film 30. The polyvinyl alcohol resin layer 6 is a layer that becomes the iodine polarizer 5 through the stretching step S10-2 and the dyeing step S10-3. The polyvinyl alcohol-based resin layer 6 can be formed by applying a coating liquid containing a polyvinyl alcohol-based resin to one or both surfaces of the base film 30 and drying it. The method of forming the polyvinyl alcohol-based resin layer by such coating is advantageous in that a thin film iodine-based polarizer 5 can be easily obtained.
 基材フィルム30は熱可塑性樹脂から構成することができ、中でも透明性、機械的強度、熱安定性、延伸性等に優れる熱可塑性樹脂から構成することが好ましい。このような熱可塑性樹脂の具体例は、例えば、鎖状ポリオレフィン系樹脂、環状ポリオレフィン系樹脂(ノルボルネン系樹脂等)のようなポリオレフィン系樹脂;ポリエステル系樹脂;(メタ)アクリル系樹脂;セルローストリアセテート、セルロースジアセテートのようなセルロースエステル系樹脂;ポリカーボネート系樹脂;ポリビニルアルコール系樹脂;ポリ酢酸ビニル系樹脂;ポリアリレート系樹脂;ポリスチレン系樹脂;ポリエーテルスルホン系樹脂;ポリスルホン系樹脂;ポリアミド系樹脂;ポリイミド系樹脂;及びこれらの混合物、共重合物を含む。 The base film 30 can be composed of a thermoplastic resin, and is preferably composed of a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, stretchability and the like. Specific examples of such 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; System resins; and mixtures and copolymers thereof.
 基材フィルム30は、1種又は2種以上の熱可塑性樹脂からなる1つの樹脂層からなる単層構造であってもよいし、1種又は2種以上の熱可塑性樹脂からなる樹脂層を複数積層した多層構造であってもよい。基材フィルム30は、後述する延伸工程S10-2において、ポリビニルアルコール系樹脂層6を延伸するのに好適な延伸温度で延伸できるような樹脂で構成されることが好ましい。 The base film 30 may have a single-layer structure made of one resin layer made of one kind or two or more kinds of thermoplastic resins, or a plurality of resin layers made of one kind or two or more kinds of thermoplastic resins. A laminated multilayer structure may be used. The base film 30 is preferably made of a resin that can be stretched at a stretching temperature suitable for stretching the polyvinyl alcohol-based resin layer 6 in the stretching step S10-2 described later.
 基材フィルム30は、添加剤を含有することができる。添加剤の具体例は、紫外線吸収剤、酸化防止剤、滑剤、可塑剤、離型剤、着色防止剤、難燃剤、核剤、帯電防止剤、顔料、及び着色剤を含む。 The base film 30 can contain an additive. Specific examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, an anti-coloring agent, a flame retardant, a nucleating agent, an antistatic agent, a pigment, and a coloring agent.
 基材フィルム30の厚みは通常、強度や取扱性等の点から1~500μmであり、好ましくは1~300μm、より好ましくは5~200μm、さらに好ましくは5~150μmである。 The thickness of the base film 30 is usually 1 to 500 μm, preferably 1 to 300 μm, more preferably 5 to 200 μm, and still more preferably 5 to 150 μm from the viewpoints of strength and handleability.
 基材フィルム30に塗工する塗工液は、好ましくはポリビニルアルコール系樹脂の粉末を良溶媒(例えば水)に溶解させて得られるポリビニルアルコール系樹脂溶液である。ポリビニルアルコール系樹脂の詳細は、上述のとおりである。塗工液は必要に応じて、可塑剤、界面活性剤等の添加剤を含有していてもよい。 The coating liquid applied to the base film 30 is preferably a polyvinyl alcohol resin solution obtained by dissolving a polyvinyl alcohol resin powder in a good solvent (for example, water). The details of the polyvinyl alcohol resin are as described above. The coating liquid may contain additives such as a plasticizer and a surfactant as necessary.
 上記塗工液を基材フィルム30に塗工する方法は、ワイヤーバーコーティング法;リバースコーティング、グラビアコーティングのようなロールコーティング法;ダイコート法;カンマコート法;リップコート法;スピンコーティング法;スクリーンコーティング法;ファウンテンコーティング法;ディッピング法;スプレー法等の方法から適宜選択することができる。 The coating liquid is applied to the base film 30 by a wire bar coating method; a roll coating method such as reverse coating or gravure coating; a die coating method; a comma coating method; a lip coating method; a spin coating method; The method can be appropriately selected from a method such as a fountain coating method, a dipping method, and a spray method.
 塗工層(乾燥前のポリビニルアルコール系樹脂層)の乾燥温度及び乾燥時間は塗工液に含まれる溶媒の種類に応じて設定される。乾燥温度は、例えば50~200℃であり、好ましくは60~150℃である。溶媒が水を含む場合、乾燥温度は80℃以上であることが好ましい。 The drying temperature and drying time of the coating layer (polyvinyl alcohol-based resin layer before drying) 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.
 ポリビニルアルコール系樹脂層6は、基材フィルム30の一方の面のみに形成してもよいし、両面に形成してもよい。両面に形成すると偏光性積層フィルム400(図6参照)の製造時に発生し得るフィルムのカールを抑制できるとともに、1枚の偏光性積層フィルム400から2枚の偏光板を得ることができるので、生産効率の面でも有利である。 The polyvinyl alcohol-based resin layer 6 may be formed only on one side of the base film 30 or on both sides. When formed on both sides, curling of the film that may occur during the production of the polarizing laminated film 400 (see FIG. 6) can be suppressed, and two polarizing plates can be obtained from one polarizing laminated film 400. It is also advantageous in terms of efficiency.
 積層フィルム200におけるポリビニルアルコール系樹脂層6の厚みは、好ましくは3~30μmであり、より好ましくは5~20μmである。この範囲内の厚みを有するポリビニルアルコール系樹脂層6であれば、後述する延伸工程S10-2及び染色工程S10-3を経て、ヨウ素の染色性が良好で偏光性能に優れ、かつ十分に薄い(例えば厚み10μm以下の)ヨウ素系偏光子5を得ることができる。 The thickness of the polyvinyl alcohol-based resin layer 6 in the laminated film 200 is preferably 3 to 30 μm, and more preferably 5 to 20 μm. If the polyvinyl alcohol-based resin layer 6 has a thickness within this range, it passes through the stretching step S10-2 and the dyeing step S10-3, which will be described later, and has good iodine dyeability, excellent polarization performance, and is sufficiently thin ( For example, an iodine-based polarizer 5 having a thickness of 10 μm or less can be obtained.
 塗工液の塗工に先立ち、基材フィルム30とポリビニルアルコール系樹脂層6との密着性を向上させるために、少なくともポリビニルアルコール系樹脂層6が形成される側の基材フィルム30の表面に、コロナ処理、プラズマ処理、フレーム(火炎)処理等を施してもよい。また同様の理由で、基材フィルム30上にプライマー層等を介してポリビニルアルコール系樹脂層6を形成してもよい。 Prior to the application of the coating liquid, in order to improve the adhesion between the base film 30 and the polyvinyl alcohol resin layer 6, at least the surface of the base film 30 on the side where the polyvinyl alcohol resin layer 6 is formed is provided. Corona treatment, plasma treatment, flame (flame) treatment or the like may be performed. For the same reason, the polyvinyl alcohol-based resin layer 6 may be formed on the base film 30 via a primer layer or the like.
 プライマー層は、プライマー層形成用塗工液を基材フィルム30の表面に塗工した後、乾燥させることにより形成することができる。この塗工液は、基材フィルム30とポリビニルアルコール系樹脂層6との両方にある程度強い密着力を発揮する成分を含み、通常は、このような密着力を付与する樹脂成分と溶媒とを含む。樹脂成分としては、好ましくは透明性、熱安定性、延伸性等に優れる熱可塑樹脂が用いられ、例えば(メタ)アクリル系樹脂、ポリビニルアルコール系樹脂等が挙げられる。中でも、良好な密着力を与えるポリビニルアルコール系樹脂が好ましく用いられる。より好ましくは、ポリビニルアルコール樹脂である。溶媒としては通常、上記樹脂成分を溶解できる一般的な有機溶媒や水系溶媒が用いられるが、水を溶媒とする塗工液からプライマー層を形成することが好ましい。 The primer layer can be formed by applying a primer layer forming coating solution onto the surface of the base film 30 and then drying it. This coating solution includes a component that exhibits a certain degree of strong adhesion to both the base film 30 and the polyvinyl alcohol-based resin layer 6, and usually includes a resin component that provides such adhesion and a solvent. . As the resin component, 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. More preferably, it is a polyvinyl alcohol resin. As the solvent, a general organic solvent or an aqueous solvent capable of dissolving the resin component is usually used, but it is preferable to form the primer layer from a coating solution containing water as a solvent.
 プライマー層の強度を上げるために、プライマー層形成用塗工液に架橋剤を添加してもよい。架橋剤の具体例は、エポキシ系、イソシアネート系、ジアルデヒド系、金属系(例えば、金属塩、金属酸化物、金属水酸化物、有機金属化合物)、高分子系の架橋剤を含む。プライマー層を形成する樹脂成分としてポリビニルアルコール系樹脂を使用する場合は、ポリアミドエポキシ樹脂、メチロール化メラミン樹脂、ジアルデヒド系架橋剤、金属キレート化合物系架橋剤等が好適に用いられる。 In order to increase the strength of the primer layer, a crosslinking agent may be added to the primer layer forming coating solution. Specific examples of the crosslinking agent include epoxy-based, isocyanate-based, dialdehyde-based, metal-based (for example, metal salts, metal oxides, metal hydroxides, organometallic compounds), and polymer-based crosslinking agents. When a polyvinyl alcohol resin is used as the resin component for forming the primer layer, a polyamide epoxy resin, a methylolated melamine resin, a dialdehyde crosslinking agent, a metal chelate compound crosslinking agent, or the like is preferably used.
 プライマー層の厚みは、0.05~1μm程度であることが好ましく、0.1~0.4μmであることがより好ましい。0.05μmより薄くなると、基材フィルム30とポリビニルアルコール系樹脂層6との密着力向上の効果が小さく、1μmより厚くなると、両面保護フィルム付偏光板の薄型化に不利である。 The thickness of the primer layer is preferably about 0.05 to 1 μm, more preferably 0.1 to 0.4 μm. When the thickness is less than 0.05 μm, the effect of improving the adhesion between the base film 30 and the polyvinyl alcohol-based resin layer 6 is small, and when the thickness is more than 1 μm, it is disadvantageous for thinning the polarizing plate with a double-sided protective film.
 プライマー層形成用塗工液を基材フィルム30に塗工する方法は、ポリビニルアルコール系樹脂層形成用の塗工液と同様であることができる。プライマー層形成用塗工液からなる塗工層の乾燥温度は、例えば50~200℃であり、好ましくは60~150℃である。溶媒が水を含む場合、乾燥温度は80℃以上であることが好ましい。 The method of applying the primer layer forming coating solution to the base film 30 can be the same as the coating solution for forming the polyvinyl alcohol-based resin layer. The drying temperature of the coating layer made of the primer layer forming coating solution is, for example, 50 to 200 ° C., and preferably 60 to 150 ° C. When the solvent contains water, the drying temperature is preferably 80 ° C. or higher.
 〔延伸工程S10-2〕
 図5を参照して本工程は、積層フィルム200を延伸して、延伸された基材フィルム30’及びポリビニルアルコール系樹脂層6’からなる延伸フィルム300を得る工程である。延伸処理は通常、一軸延伸である。
[Stretching step S10-2]
With reference to FIG. 5, this process is a process of extending the laminated film 200 to obtain a stretched film 300 composed of the stretched base film 30 ′ and the polyvinyl alcohol-based resin layer 6 ′. The stretching process is usually uniaxial stretching.
 積層フィルム200の延伸倍率は、所望する偏光特性に応じて適宜選択することができるが、好ましくは、積層フィルム200の元長に対して5倍超17倍以下であり、より好ましくは5倍超8倍以下である。延伸倍率が5倍以下であると、ポリビニルアルコール系樹脂層6’が十分に配向しないため、ヨウ素系偏光子5の偏光度が十分に高くならないことがある。一方、延伸倍率が17倍を超えると、延伸時にフィルムの破断が生じ易くなるとともに、延伸フィルム300の厚みが必要以上に薄くなり、後工程での加工性及び取扱性が低下するおそれがある。 The draw ratio of the laminated film 200 can be appropriately selected according to the desired polarization characteristics, but is preferably more than 5 times and not more than 17 times, more preferably more than 5 times the original length of the laminated film 200. 8 times or less. When the draw ratio is 5 times or less, the polyvinyl alcohol resin layer 6 ′ is not sufficiently oriented, and the degree of polarization of the iodine polarizer 5 may not be sufficiently high. On the other hand, when the draw ratio exceeds 17 times, the film is likely to be broken during stretching, and the thickness of the stretched film 300 becomes unnecessarily thin, and the workability and handleability in subsequent processes may be reduced.
 延伸処理は、一段での延伸に限定されることはなく多段で行うこともできる。この場合、多段階の延伸処理のすべてを染色工程S10-3の前に連続的に行ってもよいし、二段階目以降の延伸処理を染色工程S10-3における染色処理及び/又は架橋処理と同時に行ってもよい。このように多段で延伸処理を行う場合は、延伸処理の全段を合わせて5倍超の延伸倍率となるように延伸処理を行うことが好ましい。 The stretching process is not limited to one-stage stretching, and can be performed in multiple stages. In this case, all of the multi-stage stretching processes may be performed continuously before the dyeing step S10-3, or the second and subsequent stretching processes may be performed as a dyeing process and / or a crosslinking process in the dyeing process S10-3. You may do it at the same time. Thus, when performing a extending | stretching process in multistage, it is preferable to perform an extending | stretching process so that it may become a draw ratio more than 5 times combining all the stages of an extending | stretching process.
 延伸処理は、フィルム長手方向(フィルム搬送方向)に延伸する縦延伸であることができるほか、フィルム幅方向に延伸する横延伸又は斜め延伸等であってもよい。縦延伸方式としては、ロールを用いて延伸するロール間延伸、圧縮延伸、チャック(クリップ)を用いた延伸等が挙げられ、横延伸方式としては、テンター法等が挙げられる。延伸処理は、湿潤式延伸方法、乾式延伸方法のいずれも採用できる。 The stretching treatment may be longitudinal stretching that extends in the film longitudinal direction (film transport direction), and may be lateral stretching or oblique stretching that extends in the film width direction. Examples of the longitudinal stretching method include inter-roll stretching using a roll, compression stretching, stretching using a chuck (clip), and the like, and examples of the lateral stretching method include a tenter method. As the stretching treatment, either a wet stretching method or a dry stretching method can be adopted.
 延伸温度は、ポリビニルアルコール系樹脂層6及び基材フィルム30全体が延伸可能な程度に流動性を示す温度以上に設定され、好ましくは基材フィルム30の相転移温度(融点又はガラス転移温度)の-30℃から+30℃の範囲であり、より好ましくは-30℃から+5℃の範囲であり、さらに好ましくは-25℃から+0℃の範囲である。基材フィルム30が複数の樹脂層からなる場合、上記相転移温度は該複数の樹脂層が示す相転移温度のうち、最も高い相転移温度を意味する。 The stretching temperature is set to be equal to or higher than the temperature at which the polyvinyl alcohol-based resin layer 6 and the entire base film 30 can be stretched, and preferably the phase transition temperature (melting point or glass transition temperature) of the base film 30. It is in the range of −30 ° C. to + 30 ° C., more preferably in the range of −30 ° C. to + 5 ° C., and still more preferably in the range of −25 ° C. to + 0 ° C. When the base film 30 consists of a plurality of resin layers, the phase transition temperature means the highest phase transition temperature among the phase transition temperatures exhibited by the plurality of resin layers.
 延伸温度を相転移温度の-30℃より低くすると、5倍超の高倍率延伸が達成されにくいか、又は、基材フィルム30の流動性が低すぎて延伸処理が困難になる傾向にある。延伸温度が相転移温度の+30℃を超えると、基材フィルム30の流動性が大きすぎて延伸が困難になる傾向にある。5倍超の高延伸倍率をより達成しやすいことから、延伸温度は上記範囲内であって、さらに好ましくは120℃以上である。 When the stretching temperature is lower than the phase transition temperature of −30 ° C., it is difficult to achieve a high-magnification stretching of more than 5 times, or the fluidity of the base film 30 is too low and the stretching process tends to be difficult. When the stretching temperature exceeds + 30 ° C. of the phase transition temperature, the fluidity of the base film 30 is too large and stretching tends to be difficult. Since it is easier to achieve a high draw ratio of more than 5 times, the drawing temperature is within the above range, and more preferably 120 ° C. or higher.
 延伸処理における積層フィルム200の加熱方法としては、ゾーン加熱法(例えば、熱風を吹き込み所定の温度に調整した加熱炉のような延伸ゾーン内で加熱する方法。);ロールを用いて延伸する場合において、ロール自体を加熱する方法;ヒーター加熱法(赤外線ヒーター、ハロゲンヒーター、パネルヒーター等を積層フィルム200の上下に設置し輻射熱で加熱する方法)等がある。ロール間延伸方式においては、延伸温度の均一性の観点からゾーン加熱法が好ましい。 As a heating method of the laminated film 200 in the stretching process, a zone heating method (for example, a method in which hot air is blown and heated in a stretching zone such as a heating furnace adjusted to a predetermined temperature); And a method of heating the roll itself; a heater heating method (a method in which infrared heaters, halogen heaters, panel heaters and the like are installed above and below the laminated film 200 and heated by radiant heat) and the like. In the inter-roll stretching method, the zone heating method is preferable from the viewpoint of the uniformity of the stretching temperature.
 延伸工程S10-2に先立ち、積層フィルム200を予熱する予熱処理工程を設けてもよい。予熱方法としては、延伸処理における加熱方法と同様の方法を用いることができる。予熱温度は、延伸温度の-50℃から±0℃の範囲であることが好ましく、延伸温度の-40℃から-10℃の範囲であることがより好ましい。 Prior to the stretching step S10-2, a preheat treatment step for preheating the laminated film 200 may be provided. As the preheating method, the same method as the heating method in the stretching process can be used. The preheating temperature is preferably in the range of −50 ° C. to ± 0 ° C. of the stretching temperature, and more preferably in the range of −40 ° C. to −10 ° C. of the stretching temperature.
 また、延伸工程S10-2における延伸処理の後に、熱固定処理工程を設けてもよい。熱固定処理は、延伸フィルム300の端部をクリップにより把持した状態で緊張状態に維持しながら、結晶化温度以上で熱処理を行う処理である。この熱固定処理によってポリビニルアルコール系樹脂層6’の結晶化が促進される。熱固定処理の温度は、延伸温度の-0℃~-80℃の範囲であることが好ましく、延伸温度の-0℃~-50℃の範囲であることがより好ましい。 Further, a heat setting treatment step may be provided after the stretching treatment in the stretching step S10-2. The heat setting process is a process in which heat treatment is performed at a temperature equal to or higher than the crystallization temperature while maintaining the tensioned state with the end of the stretched film 300 held by a clip. The crystallization of the polyvinyl alcohol-based resin layer 6 'is promoted by this heat setting treatment. The temperature of the heat setting treatment is preferably in the range of −0 ° C. to −80 ° C. of the stretching temperature, and more preferably in the range of −0 ° C. to −50 ° C. of the stretching temperature.
 〔染色工程S10-3〕
 図6を参照して本工程は、延伸フィルム300のポリビニルアルコール系樹脂層6’をヨウ素で染色してこれを吸着配向させ、ヨウ素系偏光子5とする工程である。本工程を経て基材フィルム30’の片面又は両面にヨウ素系偏光子5が積層された偏光性積層フィルム400が得られる。
[Dyeing step S10-3]
With reference to FIG. 6, this step is a step in which the polyvinyl alcohol resin layer 6 ′ of the stretched film 300 is dyed with iodine and adsorbed and oriented to form the iodine polarizer 5. Through this step, a polarizing laminated film 400 in which the iodine-based polarizer 5 is laminated on one surface or both surfaces of the base film 30 ′ is obtained.
 染色工程は、ヨウ素を含有する溶液(染色溶液)に延伸フィルム300を浸漬することにより行うことができる。染色溶液としては、ヨウ素を溶媒に溶解した溶液を使用できる。溶媒としては、一般的には水が使用されるが、水と相溶性のある有機溶媒がさらに添加されてもよい。染色溶液におけるヨウ素の濃度は、好ましくは0.01~10重量%であり、より好ましくは0.02~7重量%である。 The dyeing step can be performed by immersing the stretched film 300 in a solution containing iodine (dyeing solution). As the staining solution, a solution in which iodine is dissolved in a solvent can be used. As the solvent, water is generally used, but an organic solvent compatible with water may be further added. The iodine concentration in the dyeing solution is preferably 0.01 to 10% by weight, more preferably 0.02 to 7% by weight.
 染色効率を向上できることから、染色溶液にヨウ化物をさらに添加することが好ましい。ヨウ化物としては、例えばヨウ化カリウム、ヨウ化リチウム、ヨウ化ナトリウム、ヨウ化亜鉛、ヨウ化アルミニウム、ヨウ化鉛、ヨウ化銅、ヨウ化バリウム、ヨウ化カルシウム、ヨウ化錫、ヨウ化チタン等が挙げられる。染色溶液におけるヨウ化物の濃度は、好ましくは0.01~20重量%である。ヨウ化物の中でも、ヨウ化カリウムを添加することが好ましい。ヨウ化カリウムを添加する場合、ヨウ素とヨウ化カリウムとの割合は重量比で、好ましくは1:5~1:100であり、より好ましくは1:6~1:80である。染色溶液の温度は、好ましくは10~60℃であり、より好ましくは20~40℃である。 It is preferable to further add iodide to the dyeing solution because dyeing efficiency can be improved. Examples of 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. When potassium iodide is added, the ratio of iodine to potassium iodide is preferably 1: 5 to 1: 100, more preferably 1: 6 to 1:80, by weight. The temperature of the dyeing solution is preferably 10 to 60 ° C., more preferably 20 to 40 ° C.
 なお、染色工程S10-3を延伸工程S10-2の前に行ったり、これらの工程を同時に行ったりすることも可能であるが、ポリビニルアルコール系樹脂層に吸着させるヨウ素を良好に配向させることができるよう、積層フィルム200に対して少なくともある程度の延伸処理を施した後に染色工程S10-3を実施することが好ましい。 The dyeing step S10-3 can be performed before the stretching step S10-2, or these steps can be performed at the same time, but it is possible to satisfactorily orient iodine adsorbed on the polyvinyl alcohol-based resin layer. It is preferable to perform the dyeing step S10-3 after performing at least some stretching treatment on the laminated film 200 so as to be able to do so.
 染色工程S10-3は、染色処理に引き続いて実施される架橋処理工程を含むことができる。架橋処理は、架橋剤を溶媒に溶解した溶液(架橋溶液)中に染色されたフィルムを浸漬することにより行うことができる。架橋剤としては、例えば、ホウ酸、ホウ砂のようなホウ素化合物、グリオキザール、グルタルアルデヒド等が挙げられる。架橋剤は1種のみを使用してもよいし2種以上を併用してもよい。架橋溶液の溶媒としては、水が使用できるが、水と相溶性のある有機溶媒をさらに含んでもよい。架橋溶液における架橋剤の濃度は、好ましくは1~20重量%であり、より好ましくは6~15重量%である。 The dyeing step S10-3 can include a cross-linking treatment step performed subsequent to the dyeing treatment. The crosslinking treatment can be performed by immersing a dyed film in a solution (crosslinking solution) in which a crosslinking agent is dissolved in a solvent. Examples of the crosslinking agent include boron compounds such as boric acid and borax, glyoxal, and glutaraldehyde. Only 1 type may be used for a crosslinking agent and it may use 2 or more types together. As a solvent for the crosslinking solution, water can be used, but it may further contain an organic solvent compatible with water. The concentration of the crosslinking agent in the crosslinking solution is preferably 1 to 20% by weight, more preferably 6 to 15% by weight.
 架橋溶液はヨウ化物をさらに含むことができる。ヨウ化物の添加により、ヨウ素系偏光子5の面内における偏光性能をより均一化させることができる。ヨウ化物の具体例は上記と同様である。架橋溶液におけるヨウ化物の濃度は、好ましくは0.05~15重量%であり、より好ましくは0.5~8重量%である。架橋溶液の温度は、好ましくは10~90℃である。 The crosslinking solution can further contain iodide. By adding the iodide, the polarization performance in the plane of the iodine-based polarizer 5 can be made more uniform. Specific examples of iodide are the same as described above. The concentration of iodide in the crosslinking solution is preferably 0.05 to 15% by weight, more preferably 0.5 to 8% by weight. The temperature of the crosslinking solution is preferably 10 to 90 ° C.
 なお架橋処理は、架橋剤を染色溶液中に配合することにより、染色処理と同時に行うこともできる。また、組成の異なる2種以上の架橋溶液を用いて、架橋溶液に浸漬する処理を2回以上行ってもよい。 The crosslinking treatment can be performed simultaneously with the dyeing treatment by blending a crosslinking agent in the dyeing solution. Moreover, you may perform the process immersed in a crosslinking solution 2 or more times using 2 or more types of crosslinking solutions from which a composition differs.
 染色工程S10-3の後、後述する貼合工程S10-4の前に洗浄工程及び乾燥工程を行うことが好ましい。洗浄工程は通常、水洗浄工程を含む。水洗浄処理は、イオン交換水、蒸留水のような純水に染色処理後の又は架橋処理後のフィルムを浸漬することにより行うことができる。水洗浄温度は、通常3~50℃、好ましくは4~20℃である。洗浄工程は、水洗浄工程とヨウ化物溶液による洗浄工程との組み合わせであってもよい。洗浄工程の後に行われる乾燥工程としては、自然乾燥、送風乾燥、加熱乾燥等の任意の適切な方法を採用し得る。例えば加熱乾燥の場合、乾燥温度は通常20~95℃である。 It is preferable to perform a washing step and a drying step after the dyeing step S10-3 and before the bonding step S10-4 described later. 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 washing step may be a combination of a water washing step and a washing step with an iodide solution. As a drying process performed after the washing process, any appropriate method such as natural drying, blow drying, and heat drying can be adopted. For example, in the case of heat drying, the drying temperature is usually 20 to 95 ° C.
 〔貼合工程S10-4〕
 図7を参照して本工程は、偏光性積層フィルム400のヨウ素系偏光子5上、すなわち、ヨウ素系偏光子5の基材フィルム30’とは反対側の面に第1接着剤層15を介して第1保護フィルム10を貼合することで多層フィルム500を得る工程である。第1接着剤層15を形成する接着剤については上述のとおりである。
[Bonding step S10-4]
Referring to FIG. 7, in this step, the first adhesive layer 15 is formed on the iodine-based polarizer 5 of the polarizing laminated film 400, that is, on the surface opposite to the base film 30 ′ of the iodine-based polarizer 5. It is the process of obtaining the multilayer film 500 by bonding the 1st protective film 10 through. The adhesive that forms the first adhesive layer 15 is as described above.
 なお、偏光性積層フィルム400が基材フィルム30’の両面にヨウ素系偏光子5を有する場合は通常、両面のヨウ素系偏光子5上にそれぞれ第1保護フィルム10が貼合される。この場合、これらの第1保護フィルム10は同種の保護フィルムであってもよいし、異種の保護フィルムであってもよい。 In addition, when the polarizing laminated film 400 has the iodine type polarizer 5 on both surfaces of the base film 30 ′, the first protective film 10 is usually bonded to the both surfaces of the iodine type polarizer 5. In this case, these first protective films 10 may be the same type of protective film or different types of protective films.
 活性エネルギー線硬化性接着剤を用いて第1保護フィルム10を貼合する場合、第1接着剤層15となる活性エネルギー線硬化性接着剤を介して第1保護フィルム10をヨウ素系偏光子5上に積層した後、紫外線、可視光、電子線、X線のような活性エネルギー線を照射して接着剤層を硬化させる。中でも紫外線が好適であり、この場合の光源としては、低圧水銀灯、中圧水銀灯、高圧水銀灯、超高圧水銀灯、ケミカルランプ、ブラックライトランプ、マイクロウェーブ励起水銀灯、メタルハライドランプ等を用いることができる。水系接着剤を用いる場合は、水系接着剤を介して第1保護フィルム10をヨウ素系偏光子5上に積層した後、加熱乾燥させればよい。 When bonding the 1st protective film 10 using an active energy ray hardening adhesive, the iodine type polarizer 5 is attached to the 1st protective film 10 through the active energy ray hardening adhesive used as the 1st adhesive layer 15. FIG. After the lamination, the adhesive layer is cured by irradiating with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays. Among them, ultraviolet rays are preferable, and as a light source in this case, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, a metal halide lamp, or the like can be used. In the case of using an aqueous adhesive, the first protective film 10 may be laminated on the iodine polarizer 5 through the aqueous adhesive and then dried by heating.
 ヨウ素系偏光子5に第1保護フィルム10を貼合するにあたり、第1保護フィルム10及び/又はヨウ素系偏光子5の貼合面には、ヨウ素系偏光子5との接着性を向上させるために、プラズマ処理、コロナ処理、紫外線照射処理、フレーム(火炎)処理、ケン化処理のような表面処理(易接着処理)を行うことができ、中でも、プラズマ処理、コロナ処理又はケン化処理を行うことが好ましい。 In bonding the first protective film 10 to the iodine-based polarizer 5, in order to improve the adhesion with the iodine-based polarizer 5 on the bonding surface of the first protective film 10 and / or the iodine-based polarizer 5. In addition, surface treatment (easily adhesion treatment) such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame (flame) treatment, and saponification treatment can be performed. Among them, plasma treatment, corona treatment or saponification treatment is performed. It is preferable.
 〔剥離工程S10-5〕
 本工程は、多層フィルム500から基材フィルム30’を剥離除去する工程である。この工程を経て、図2と同様の片面保護フィルム付偏光板100が得られる。偏光性積層フィルム400が基材フィルム30’の両面にヨウ素系偏光子5を有し、これら両方のヨウ素系偏光子5に第1保護フィルム10を貼合した場合には、この剥離工程S50により、1枚の偏光性積層フィルム400から2枚の片面保護フィルム付偏光板100が得られる。
[Peeling step S10-5]
This step is a step of peeling and removing the base film 30 ′ from the multilayer film 500. Through this step, the same polarizing plate 100 with a single-sided protective film as in FIG. 2 is obtained. When the polarizing laminated film 400 has the iodine-based polarizer 5 on both surfaces of the base film 30 ′, and the first protective film 10 is bonded to both the iodine-based polarizers 5, the peeling step S 50 Two polarizing plates with a single-sided protective film 100 can be obtained from one polarizing laminated film 400.
 基材フィルム30’を剥離除去する方法は特に限定されるものでなく、通常の粘着剤付偏光板で行われるセパレータ(剥離フィルム)の剥離工程と同様の方法で剥離できる。基材フィルム30’は、貼合工程S10-4の後、そのまますぐ剥離してもよいし、貼合工程S10-4の後、一度ロール状に巻き取り、その後の工程で巻き出しながら剥離してもよい。 The method for peeling and removing the base film 30 ′ is not particularly limited, and can be peeled by the same method as the peeling step of a separator (peeling film) performed with a normal pressure-sensitive adhesive polarizing plate. The substrate film 30 ′ may be peeled off immediately after the bonding step S10-4, or wound once in a roll after the bonding step S10-4, and peeled off while being unwound in the subsequent steps. May be.
 (2)両面保護フィルム付偏光板作製工程S20
 本工程にて、片面保護フィルム付偏光板100におけるヨウ素系偏光子5の外面に第2保護フィルム20を貼合することにより、両面保護フィルム付偏光板が得られる。両面保護フィルム付偏光板の層構成の一例を図8に示す。図8に示される両面保護フィルム付偏光板600のように、第2保護フィルム20は通常、第2接着剤層25を介してヨウ素系偏光子5に貼合(接着固定)される。ヨウ素系偏光子5の外面とは、ヨウ素系偏光子5における第1保護フィルム10とは反対側の面を意味し、基材フィルム30’を剥離除去する工程を経て片面保護フィルム付偏光板100を作製する場合には、基材フィルム30’の剥離除去によって露出したヨウ素系偏光子5の表面を意味する。
(2) Polarizing plate making process S20 with double-sided protective film
At this process, the polarizing plate with a double-sided protective film is obtained by bonding the 2nd protective film 20 to the outer surface of the iodine type polarizer 5 in the polarizing plate 100 with a single-sided protective film. An example of the layer structure of the polarizing plate with a double-sided protective film is shown in FIG. Like the polarizing plate 600 with a double-sided protective film shown in FIG. 8, the second protective film 20 is usually bonded (adhered and fixed) to the iodine-based polarizer 5 via the second adhesive layer 25. The outer surface of the iodine-based polarizer 5 means a surface of the iodine-based polarizer 5 opposite to the first protective film 10, and a polarizing plate 100 with a single-sided protective film through a step of peeling and removing the base film 30 ′. Means the surface of the iodine-based polarizer 5 exposed by peeling off the base film 30 ′.
 第2保護フィルム20もまた、第1保護フィルム10と同様、透光性を有する(好ましくは光学的に透明な)熱可塑性樹脂からなり、かつ透湿度が150g/m2/24hr以下のフィルムである。位相差フィルム、輝度向上フィルムのような光学機能を併せ持つ保護フィルムであってもよい。第2保護フィルム20が有し得る表面処理層及びフィルムの厚み、材質等については、第1保護フィルム10について述べた上の記載が引用される。第1保護フィルム10と第2保護フィルム20とは、互いに同種の樹脂からなる保護フィルムであってもよいし、異種の樹脂からなる保護フィルムであってもよい。 Also the second protective film 20, similarly to the first protective film 10, having a light transmitting property (a preferably optically clear) a thermoplastic resin, and moisture permeability by the following film 150 g / m 2/24 hr or is there. A protective film having both optical functions such as a retardation film and a brightness enhancement film may be used. Regarding the surface treatment layer that the second protective film 20 may have and the thickness, material, and the like of the film, the above description of the first protective film 10 is cited. The first protective film 10 and the second protective film 20 may be protective films made of the same kind of resin or may be protective films made of different kinds of resins.
 第2接着剤層25を形成する接着剤は、第1接着剤層15と同様、活性エネルギー線硬化性接着剤又は水系接着剤であることができるが、好ましくは紫外線硬化性接着剤のような活性エネルギー線硬化性接着剤である。水系接着剤を用いると、ヨウ素系偏光子5に水分を供給することになるため、第2保護フィルム20を貼合するときのヨウ素系偏光子5の水分率が8重量%未満とならないことがある。第2接着剤層25を形成する接着剤は、第1接着剤層15を形成する接着剤と同じ組成を有していてもよいし、異なる組成を有していてもよい。 The adhesive forming the second adhesive layer 25 can be an active energy ray curable adhesive or an aqueous adhesive, like the first adhesive layer 15, but preferably an ultraviolet curable adhesive or the like. It is an active energy ray-curable adhesive. When the water-based adhesive is used, moisture is supplied to the iodine-based polarizer 5, so that the moisture content of the iodine-based polarizer 5 when the second protective film 20 is bonded may not be less than 8% by weight. is there. The adhesive forming the second adhesive layer 25 may have the same composition as the adhesive forming the first adhesive layer 15, or may have a different composition.
 (3)水分率低減工程S30
 本発明に係る両面保護フィルム付偏光板の製造方法は、第2保護フィルム20を貼合するときのヨウ素系偏光子5の水分率を8重量%未満とするために、上で説明したような両面保護フィルム付偏光板を製造する工程中、両面保護フィルム付偏光板作製工程S20の前のいずれか1以上の段階で実施される水分率低減工程S30を含む。水分率低減工程S30は、ヨウ素系偏光子5を含むフィルムに対してヨウ素系偏光子5の水分率を低減させる処理を施す工程である。
(3) Moisture content reduction step S30
The manufacturing method of the polarizing plate with a double-sided protective film according to the present invention is as described above so that the moisture content of the iodine-based polarizer 5 when the second protective film 20 is bonded is less than 8% by weight. In the process of manufacturing a polarizing plate with a double-sided protective film, a moisture content reducing step S30 is performed at any one or more stages before the polarizing plate-preparing step with a double-sided protective film S20. The moisture content reduction step S <b> 30 is a step of performing a process of reducing the moisture content of the iodine polarizer 5 on the film including the iodine polarizer 5.
 水分率低減工程S30を実施するタイミングの例を挙げれば、次のとおりである。
 1)単体(単独)フィルムからなるヨウ素系偏光子5の片面に第1保護フィルム10を貼合して片面保護フィルム付偏光板100を得た後、第2保護フィルム20を貼合する方法にあっては、第1保護フィルム10の貼合前、貼合後(両面保護フィルム付偏光板作製工程S20の直前を含む)又はこれらの双方。ただし、単体(単独)フィルムの状態で水分率を下げるとヨウ素系偏光子5が裂けたり、破断したりしやすくなるため、好ましくは第1保護フィルム10の貼合後である。
An example of the timing at which the moisture content reduction step S30 is performed is as follows.
1) After sticking the 1st protective film 10 on the single side | surface of the iodine type polarizer 5 which consists of a single-piece | unit (single) film, and obtaining the polarizing plate 100 with a single-sided protective film, the method of bonding the 2nd protective film 20 is carried out. If it exists, before pasting of the 1st protective film 10, after pasting (including immediately before polarizing plate production process S20 with double-sided protective film), or both. However, if the moisture content is lowered in the state of a single (single) film, the iodine-based polarizer 5 is easily torn or broken, and therefore preferably after the first protective film 10 is bonded.
 2)図3に示される方法に従って片面保護フィルム付偏光板100を得た後、第2保護フィルム20を貼合する方法にあっては、染色工程S10-3後、貼合工程S10-4後、剥離工程S10-5後(両面保護フィルム付偏光板作製工程S20の直前を含む)、又はこれらの2以上の段階。水分率を低減させやすいことから、水分率低減工程S30は、ヨウ素系偏光子5の表面が露出している段階、例えば貼合工程S10-4前や、剥離工程S10-5後に行うことが好ましい。 2) After obtaining the polarizing plate 100 with a single-side protective film according to the method shown in FIG. 3, in the method of laminating the second protective film 20, after the dyeing step S10-3, after the laminating step S10-4 After the peeling step S10-5 (including immediately before the polarizing plate production step S20 with double-sided protective film), or two or more of these steps. Since it is easy to reduce the moisture content, the moisture content reducing step S30 is preferably performed at a stage where the surface of the iodine-based polarizer 5 is exposed, for example, before the bonding step S10-4 or after the peeling step S10-5. .
 例えば上記2)において貼合工程S10-4の前に水分率低減工程S30を実施する場合のように、上記1)又は2)にかかわらず、水分率低減工程S30と両面保護フィルム付偏光板作製工程S20との間に比較的長いインターバルがあるときには、このインターバル中の吸湿によって第2保護フィルム20の貼合時に水分率が8重量%以上になることがないよう、吸湿抑制手段を講じるか、又はこのインターバル中に再度の水分率低減工程S30を実施してもよい。 For example, as in the case of performing the moisture content reduction step S30 before the bonding step S10-4 in the above 2), regardless of the above 1) or 2), the moisture content reduction step S30 and the polarizing plate with a double-sided protective film are produced. When there is a relatively long interval between step S20, take moisture absorption suppression means so that the moisture content does not become 8% by weight or more when the second protective film 20 is bonded due to moisture absorption during this interval, Alternatively, the moisture content reduction step S30 may be performed again during this interval.
 吸湿抑制手段としては、ヨウ素系偏光子5の露出面に剥離可能な防湿性フィルムを仮貼合する方法や、露出表面を有するヨウ素系偏光子5を含むフィルムの形成を伴う工程を終えた後のできるだけ早いうちにフィルムをロール状に巻回して外部からの水分の侵入を抑制する方法、ロール状のフィルムをアルミラミネートのような防湿性フィルムでさらに梱包する方法等が挙げられる。ロール状に巻回する方法は、巻回されるフィルムが基材フィルムを有しており、この基材フィルムが透湿性の低いものである場合に特に有利である。あるいは、以上のような吸湿抑制手段を特段講じることなく、ヨウ素系偏光子5の吸湿速度を考慮して、吸湿によって水分率が8重量%以上となる前に両面保護フィルム付偏光板作製工程S20を実施できるよう工程を設計してもよい。 As a moisture absorption suppressing means, after finishing a method involving temporarily pasting a peelable moisture-proof film on the exposed surface of the iodine-based polarizer 5 or a process involving forming a film including the iodine-based polarizer 5 having an exposed surface. Examples include a method of winding a film in a roll shape as soon as possible to suppress the entry of moisture from the outside, and a method of further packing the roll film with a moisture-proof film such as an aluminum laminate. The method of winding in a roll shape is particularly advantageous when the film to be wound has a base film, and the base film has a low moisture permeability. Alternatively, without taking the above-described moisture absorption suppressing means, taking into consideration the moisture absorption rate of the iodine-based polarizer 5, the polarizing plate with a double-sided protective film is produced before moisture content becomes 8% by weight or more due to moisture absorption. The process may be designed so that
 また、例えば水分率低減工程S30と両面保護フィルム付偏光板作製工程S20との間に比較的長いインターバルがあるときには、ヨウ素系偏光子5の吸湿速度を考慮して、水分率低減工程S30において8重量%よりも十分低めに水分率を下げておいてもよい。この方法によっても、水分率低減工程S30と両面保護フィルム付偏光板作製工程S20との間で特段の手段を講じることなく、第2保護フィルム20を貼合するときの水分率を8重量%未満にすることが可能である。 For example, when there is a relatively long interval between the moisture content reduction step S30 and the polarizing plate production step S20 with a double-sided protective film, the moisture content reduction step S30 takes into account 8 in consideration of the moisture absorption rate of the iodine-based polarizer 5. The moisture content may be lowered sufficiently lower than the weight%. Also by this method, the moisture content when bonding the 2nd protective film 20 is less than 8 weight%, without taking a special means between moisture content reduction process S30 and polarizing plate preparation process S20 with a double-sided protective film. It is possible to
 上述のように、ヨウ素系偏光子5と第1保護フィルム10との貼合に水系接着剤を用いることができるが、水系接着剤を用いると、ヨウ素系偏光子5に水分を供給することになるため、第1保護フィルム10を貼合してから第2保護フィルム20を貼合までの間に水分率低減工程S30を行うことが好ましい。なお、この水分率低減工程S30は最初の水分率低減工程S30である必要はない。 As described above, a water-based adhesive can be used for laminating the iodine-based polarizer 5 and the first protective film 10, but when the water-based adhesive is used, moisture is supplied to the iodine-based polarizer 5. Therefore, it is preferable to perform the moisture content reduction step S30 after the first protective film 10 is bonded and before the second protective film 20 is bonded. In addition, this moisture content reduction process S30 does not need to be the first moisture content reduction process S30.
 耐熱性の観点から、第2保護フィルム20を貼合するときのヨウ素系偏光子5の水分率は、6重量%未満であることが好ましく、5重量%以下であることがより好ましい。水分率を低減させるための具体的方法は特に制限されず、例えば、乾燥エアーを吹き付ける方法、低湿度に調整された調湿ゾーンを通過させる方法、熱風乾燥炉を通過させる方法、赤外線ヒーターのような加熱装置を用いて加熱する方法、及びこれらの組み合わせを挙げることができる。 From the viewpoint of heat resistance, the moisture content of the iodine-based polarizer 5 when the second protective film 20 is bonded is preferably less than 6% by weight, and more preferably 5% by weight or less. The specific method for reducing the moisture content is not particularly limited. For example, a method of blowing dry air, a method of passing through a humidity control zone adjusted to low humidity, a method of passing through a hot air drying furnace, an infrared heater, etc. And a method of heating using a simple heating device, and combinations thereof.
 <両面保護フィルム付偏光板>
 本発明に係る両面保護フィルム付偏光板は、図8に示されるように、ヨウ素系偏光子5と、その一方の面に積層される第1保護フィルム10と、他方の面に積層される第2保護フィルム20とを含むものである。通常、第1保護フィルム10、第2保護フィルム20はそれぞれ、第1接着剤層15、第2接着剤層25を介してヨウ素系偏光子5に貼合(接着固定)される。
<Polarizing plate with double-sided protective film>
As shown in FIG. 8, the polarizing plate with a double-sided protective film according to the present invention includes an iodine-based polarizer 5, a first protective film 10 laminated on one surface thereof, and a first laminated film on the other surface. 2 protective film 20. Usually, the 1st protective film 10 and the 2nd protective film 20 are bonded (adhesion fixation) to the iodine type polarizer 5 through the 1st adhesive bond layer 15 and the 2nd adhesive bond layer 25, respectively.
 本発明に係る両面保護フィルム付偏光板において、ヨウ素系偏光子5の水分率は8重量%未満であり、好ましくは6重量%未満、より好ましくは5重量%以下である。また、第1保護フィルム10及び第2保護フィルム20にはともに、透湿度150g/m2/24hr以下、好ましくは100g/m2/24hr以下の熱可塑性樹脂フィルムが用いられる。ヨウ素系偏光子5、第1保護フィルム10及び第2保護フィルム20の具体的構成については、上の記載が引用される。 In the polarizing plate with a double-sided protective film according to the present invention, the moisture content of the iodine polarizer 5 is less than 8% by weight, preferably less than 6% by weight, and more preferably 5% by weight or less. Further, the first protective film 10 and the second protective film 20 both moisture permeability 150 g / m 2/24 hr or less, preferably 100 g / m 2/24 hr or less of the thermoplastic resin film is used. The above description is cited for specific configurations of the iodine-based polarizer 5, the first protective film 10, and the second protective film 20.
 本発明に係る両面保護フィルム付偏光板は、上で説明した方法によって好適に製造することができる。本発明に係る両面保護フィルム付偏光板は、ヨウ素系偏光子5の水分率が8重量%未満であり、かつ低透湿度の保護フィルムを両面に積層したものであるので、ヨウ素系偏光子5の厚みが小さい(例えば厚み10μm以下の)場合であっても、耐湿熱性及び耐熱性を兼備したものとなる。両面保護フィルム付偏光板は、液晶表示装置や有機EL装置のような画像表示装置に好適に適用することができる。液晶表示装置に適用する場合において、本発明に係る両面保護フィルム付偏光板は、液晶セルの前面(視認)側に配置される偏光板であってもよいし、背面(バックライト)側に配置される偏光板であってもよい。 The polarizing plate with a double-sided protective film according to the present invention can be preferably produced by the method described above. The polarizing plate with a double-sided protective film according to the present invention has a moisture content of less than 8% by weight of the iodine-based polarizer 5 and is laminated with a low moisture-permeable protective film on both surfaces. Even when the thickness of the film is small (for example, 10 μm or less in thickness), it has both heat and moisture resistance. The polarizing plate with a double-sided protective film can be suitably applied to an image display device such as a liquid crystal display device or an organic EL device. When applied to a liquid crystal display device, the polarizing plate with a double-sided protective film according to the present invention may be a polarizing plate disposed on the front (viewing) side of the liquid crystal cell, or disposed on the back (backlight) side. It may be a polarizing plate.
 両面保護フィルム付偏光板は、第1保護フィルム10又は第2保護フィルム20上に積層される、他の部材(例えば液晶表示装置に適用する場合における液晶セル)に貼合するための粘着剤層を備えていてもよい。粘着剤層を形成する粘着剤は通常、(メタ)アクリル系樹脂、スチレン系樹脂、シリコーン系樹脂等をベースポリマーとし、そこに、イソシアネート化合物、エポキシ化合物、アジリジン化合物のような架橋剤を加えた粘着剤組成物からなる。さらに微粒子を含有して光散乱性を示す粘着剤層とすることもできる。粘着剤層の厚みは通常、1~40μmであり、好ましくは3~25μmである。 The polarizing plate with a double-sided protective film is a pressure-sensitive adhesive layer that is laminated on the first protective film 10 or the second protective film 20 and is bonded to another member (for example, a liquid crystal cell when applied to a liquid crystal display device). May be provided. The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is usually based on a (meth) 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 is added thereto. It consists of an adhesive composition. Furthermore, it can also be set as the adhesive layer which contains microparticles | fine-particles and shows light-scattering property. The thickness of the pressure-sensitive adhesive layer is usually 1 to 40 μm, preferably 3 to 25 μm.
 また両面保護フィルム付偏光板は、第1保護フィルム10又は第2保護フィルム20上に積層される他の光学層をさらに備えることができる。他の光学層としては、ある種の偏光光を透過し、それと逆の性質を示す偏光光を反射する反射型偏光フィルム;表面に凹凸形状を有する防眩機能付フィルム;表面反射防止機能付フィルム;表面に反射機能を有する反射フィルム;反射機能と透過機能とを併せ持つ半透過反射フィルム;視野角補償フィルム等が挙げられる。 The polarizing plate with a double-sided protective film can further include another optical layer laminated on the first protective film 10 or the second protective film 20. As another optical layer, a reflective polarizing film that transmits a certain kind of polarized light and reflects polarized light that exhibits the opposite properties; a film with an antiglare function having a concavo-convex 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.
 以下、実施例及び比較例を示して本発明をさらに具体的に説明するが、本発明はこれらの例によって限定されるものではない。 Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.
 <実施例1>
 (1)プライマー層形成工程
 ポリビニルアルコール粉末(日本合成化学工業(株)製の「Z-200」、平均重合度1100、ケン化度99.5モル%)を95℃の熱水に溶解し、濃度3重量%のポリビニルアルコール水溶液を調製した。得られた水溶液に架橋剤(田岡化学工業(株)製の「スミレーズレジン650」)をポリビニルアルコール粉末6重量部に対して5重量部の割合で混合して、プライマー層形成用塗工液を得た。
<Example 1>
(1) Primer layer forming step Polyvinyl alcohol powder (“Z-200” manufactured by Nippon Synthetic Chemical Industry Co., Ltd., average polymerization degree 1100, saponification degree 99.5 mol%) was dissolved in 95 ° C. hot water, A polyvinyl alcohol aqueous solution having a concentration of 3% by weight was prepared. The resulting aqueous solution was mixed with a crosslinking agent (“Smiles Resin 650” manufactured by Taoka Chemical Co., Ltd.) at a ratio of 5 parts by weight to 6 parts by weight of the polyvinyl alcohol powder to form a primer layer forming coating solution. Got.
 次に、ポリプロピレンからなる厚み90μmの基材フィルム(融点:163℃、透湿度:15g/m2/24hr)の片面にコロナ処理を施した後、そのコロナ処理面に小径グラビアコーターを用いて上記プライマー層形成用塗工液を塗工し、80℃で10分間乾燥させることにより、厚み0.2μmのプライマー層を形成した。 Next, the substrate film having a thickness of 90μm made of polypropylene (melting point: 163 ° C., moisture permeability: 15g / m 2 / 24hr) was subjected to corona treatment on one surface of, using a small-diameter gravure coater on the corona-treated surface above The primer layer-forming coating solution was applied and dried at 80 ° C. for 10 minutes to form a primer layer having a thickness of 0.2 μm.
 (2)積層フィルムの作製(樹脂層形成工程)
 ポリビニルアルコール粉末((株)クラレ製の「PVA124」、平均重合度2400、ケン化度98.0~99.0モル%)を95℃の熱水に溶解し、濃度8重量%のポリビニルアルコール水溶液を調製し、これをポリビニルアルコール系樹脂層形成用塗工液とした。
(2) Production of laminated film (resin layer forming step)
Polyvinyl alcohol powder (“PVA124” manufactured by Kuraray Co., Ltd., average polymerization degree 2400, saponification degree 98.0 to 99.0 mol%) was dissolved in hot water at 95 ° C., and a polyvinyl alcohol aqueous solution having a concentration of 8% by weight. This was used as a coating liquid for forming a polyvinyl alcohol resin layer.
 上記(1)で作製したプライマー層を有する基材フィルムのプライマー層表面にダイコーターを用いて上記ポリビニルアルコール系樹脂層形成用塗工液を塗工した後、80℃で20分間乾燥させることにより、プライマー層上にポリビニルアルコール系樹脂層を形成して、基材フィルム/プライマー層/ポリビニルアルコール系樹脂層からなる積層フィルムを得た。 By applying the polyvinyl alcohol-based resin layer forming coating solution to the surface of the primer layer of the base film having the primer layer prepared in (1) above using a die coater, and then drying at 80 ° C. for 20 minutes. Then, a polyvinyl alcohol-based resin layer was formed on the primer layer to obtain a laminated film composed of base film / primer layer / polyvinyl alcohol-based resin layer.
 (3)延伸フィルムの作製(延伸工程)
 上記(2)で作製した積層フィルムに対し、フローティングの縦一軸延伸装置を用いて160℃で5.3倍の自由端一軸延伸を実施し、延伸フィルムを得た。延伸後のポリビニルアルコール系樹脂層の厚みは5.1μmであった。
(3) Production of stretched film (stretching process)
The laminated film produced in the above (2) was subjected to 5.3 times free end uniaxial stretching at 160 ° C. using a floating longitudinal uniaxial stretching apparatus to obtain a stretched film. The thickness of the stretched polyvinyl alcohol resin layer was 5.1 μm.
 (4)偏光性積層フィルムの作製(染色工程)
 上記(3)で作製した延伸フィルムを、ヨウ素とヨウ化カリウムとを含む30℃の染色水溶液(水100重量部あたりヨウ素を0.6重量部、ヨウ化カリウムを10重量部含む)に約180秒間浸漬してポリビニルアルコール系樹脂層の染色処理を行った後、10℃の純水で余分な染色水溶液を洗い流した。
(4) Production of polarizing laminated film (dyeing process)
The stretched film prepared in the above (3) is added to a dyeing aqueous solution at 30 ° C. containing iodine and potassium iodide (containing 0.6 parts by weight of iodine and 10 parts by weight of potassium iodide per 100 parts by weight of water). After immersing for 2 seconds, the polyvinyl alcohol-based resin layer was dyed, and the excess dyeing aqueous solution was washed away with pure water at 10 ° C.
 次に、ホウ酸を含む78℃の第1架橋水溶液(水100重量部あたりホウ酸を10.4重量部含む)に120秒間浸漬し、次いで、ホウ酸及びヨウ化カリウムを含む70℃の第2架橋水溶液(水100重量部あたりホウ酸を5.7重量部、ヨウ化カリウムを12重量部含む)に60秒間浸漬して架橋処理を行った。その後、10℃の純水で10秒間洗浄した。最後に50℃で60秒間、次いで80℃で60秒間乾燥させることにより(水分率低減工程)、基材フィルム/ヨウ素系偏光子からなる偏光性積層フィルムを得た。乾燥終了時点での偏光性積層フィルムが有するヨウ素系偏光子の水分率は、0.4重量%であった。また、ヨウ素系偏光子の厚みは5.6μmであった。 Next, it is immersed for 120 seconds in a first aqueous crosslinked solution at 78 ° C. containing boric acid (containing 10.4 parts by weight boric acid per 100 parts by weight of water), and then a 70 ° C. aqueous solution containing boric acid and potassium iodide. 2 A crosslinking treatment was performed by immersing in a crosslinking aqueous solution (containing 5.7 parts by weight of boric acid and 12 parts by weight of potassium iodide per 100 parts by weight of water) for 60 seconds. Thereafter, it was washed with pure water at 10 ° C. for 10 seconds. Finally, it was dried at 50 ° C. for 60 seconds and then at 80 ° C. for 60 seconds (moisture content reduction step) to obtain a polarizing laminated film composed of a base film / iodine polarizer. The moisture content of the iodine-type polarizer of the polarizing laminated film at the end of drying was 0.4% by weight. The iodine polarizer had a thickness of 5.6 μm.
 空気中の水分を吸湿してヨウ素系偏光子の水分率が上昇することを抑制できるよう、ヨウ素系偏光子における基材フィルムとは反対側の面に、再剥離性を有し、透湿度の低い防湿性フィルム(透湿度30g/m2/24hrのポリオレフィン系樹脂フィルム)を、乾燥後すぐに貼合した。これによりヨウ素系偏光子は、低透湿度の基材フィルム及び防湿性フィルムで挟まれるため、低水分率を維持できる。 The surface of the iodine polarizer opposite to the base film has removability so that moisture content in the air can be absorbed and moisture content of the iodine polarizer can be suppressed. the low moisture resistance film (polyolefin resin film of moisture permeability 30g / m 2 / 24hr), was stuck after drying quickly. Thereby, since an iodine type polarizer is pinched | interposed by the base film and moisture proof film of a low moisture permeability, it can maintain a low moisture content.
 (5)多層フィルムの作製(貼合工程)
 上記(4)で作製した防湿性フィルム付の偏光性積層フィルムから防湿性フィルムを剥離しながらすぐに(1分以内に)、その剥離面に第1保護フィルムを貼合した。第1保護フィルムには、透湿度が16g/m2/24hrであり、環状ポリオレフィン系樹脂からなる厚み23μmの熱可塑性樹脂フィルム(日本ゼオン(株)製の「ZF-14」)を用いた。第1保護フィルムの貼合は、その片面に紫外線硬化性接着剤((株)ADEKA製の「KR-75T」)を硬化後の厚みが1.0μm程度となるように小径グラビアコーターを用いて塗工した後、これを、貼合ロールを用いて上記剥離面に貼合し、その後、高圧水銀ランプを用いて、基材フィルム側から200mJ/cm2の積算光量で紫外線を照射して接着剤層を硬化させることにより行った。
(5) Production of multilayer film (bonding process)
Immediately (within 1 minute) while peeling the moisture-proof film from the polarizing laminated film with the moisture-proof film prepared in (4) above, the first protective film was bonded to the peeled surface. The first protective film, the moisture permeability is 16g / m 2 / 24hr, using thermoplastic resin film 23μm thick made of cyclic polyolefin resin (Nippon Zeon's "ZF-14"). The first protective film is bonded using a small-diameter gravure coater so that the thickness after curing the ultraviolet curable adhesive (“KR-75T” manufactured by ADEKA Co., Ltd.) on the one side is about 1.0 μm. After coating, this is bonded to the release surface using a bonding roll, and then irradiated with ultraviolet light with a cumulative amount of 200 mJ / cm 2 from the base film side using a high-pressure mercury lamp and bonded. This was done by curing the agent layer.
 (6)両面保護フィルム付偏光板の作製(剥離工程及び両面保護フィルム付偏光板作製工程)
 上記(5)で作製した多層フィルムから基材フィルムを剥離しながらすぐに、その剥離面に第2保護フィルムを貼合して、第1保護フィルム/接着剤層/ヨウ素系偏光子/接着剤層/第2保護フィルムからなる両面保護フィルム付偏光板を得た。第2保護フィルムには、透湿度が16g/m2/24hrであり、環状ポリオレフィン系樹脂からなる厚み23μmの熱可塑性樹脂フィルム(日本ゼオン(株)製の「ZF-14」)を用いた。第2保護フィルムの貼合は、その片面に紫外線硬化性接着剤((株)ADEKA製の「KR-75T」)を硬化後の厚みが1.0μm程度となるように小径グラビアコーターを用いて塗工した後、これを、貼合ロールを用いて上記剥離面に貼合し、その後、高圧水銀ランプを用いて、第2保護フィルム側から200mJ/cm2の積算光量で紫外線を照射して接着剤層を硬化させることにより行った。第2保護フィルムを貼合するときのヨウ素系偏光子の水分率は、0.5重量%であった。
(6) Preparation of polarizing plate with double-sided protective film (peeling step and polarizing plate with double-sided protective film)
Immediately after peeling the base film from the multilayer film produced in (5) above, a second protective film is bonded to the peeled surface, and the first protective film / adhesive layer / iodine polarizer / adhesive. A polarizing plate with a double-sided protective film comprising a layer / second protective film was obtained. The second protective film, the moisture permeability is 16g / m 2 / 24hr, using thermoplastic resin film 23μm thick made of cyclic polyolefin resin (Nippon Zeon's "ZF-14"). The second protective film is bonded using a small-diameter gravure coater so that the thickness after curing the ultraviolet curable adhesive (“KR-75T” manufactured by ADEKA Co., Ltd.) is about 1.0 μm on one side. After coating, this is bonded to the release surface using a bonding roll, and then irradiated with ultraviolet light with an integrated light amount of 200 mJ / cm 2 from the second protective film side using a high-pressure mercury lamp. This was done by curing the adhesive layer. The moisture content of the iodine-type polarizer when bonding the second protective film was 0.5% by weight.
 <実施例2>
 染色工程最後の乾燥処理(水分率低減工程)の条件を、50℃で60秒間、次いで65℃で60秒間としたこと以外は実施例1と同様にして、両面保護フィルム付偏光板を作製した。第2保護フィルムを貼合するときのヨウ素系偏光子の水分率は、4.6重量%であった。
<Example 2>
A polarizing plate with a double-sided protective film was produced in the same manner as in Example 1, except that the final drying treatment (moisture content reduction step) was performed at 50 ° C. for 60 seconds and then at 65 ° C. for 60 seconds. . The moisture content of the iodine-based polarizer when the second protective film was bonded was 4.6% by weight.
 <実施例3>
 実施例2と同様にして、両面保護フィルム付偏光板を作製した。第2保護フィルムを貼合するときのヨウ素系偏光子の水分率は4.4重量%であり、両面保護フィルム付偏光板の視感度補正偏光度Pyは99.995%、視感度補正単体透過率Tyは40.9%であった。
<Example 3>
In the same manner as in Example 2, a polarizing plate with a double-sided protective film was produced. The moisture content of the iodine-based polarizer when the second protective film is bonded is 4.4% by weight, and the visibility correction polarization degree Py of the polarizing plate with a double-sided protection film is 99.995%, and the visibility correction single transmission is performed. The rate Ty was 40.9%.
 <実施例4>
 第1保護フィルム及び第2保護フィルムとして、透湿度が63g/m2/24hrであり、アクリル系樹脂からなる厚み80μmの熱可塑性樹脂フィルムを用い、紫外線硬化性接着剤((株)ADEKA製の「KR-15P」)を用いた以外は、実施例2と同様にして、両面保護フィルム付偏光板を作製した。第2保護フィルムを貼合するときのヨウ素系偏光子の水分率は4.2重量%であり、両面保護フィルム付偏光板の視感度補正偏光度Pyは99.994%、視感度補正単体透過率Tyは41.4%であった。
<Example 4>
As the first protective film and second protective film, the moisture permeability is 63 g / m 2/24 hr or, using a thermoplastic resin film having a thickness of 80μm made of an acrylic resin, an ultraviolet curable adhesive ((Ltd.) ADEKA manufactured A polarizing plate with a double-sided protective film was produced in the same manner as in Example 2 except that “KR-15P”) was used. When the second protective film is bonded, the moisture content of the iodine-based polarizer is 4.2% by weight, the visibility correction polarization degree Py of the polarizing plate with a double-sided protection film is 99.994%, and the visibility correction single transmission. The rate Ty was 41.4%.
 <実施例5>
 第1保護フィルムとして、透湿度が63g/m2/24hrであり、アクリル系樹脂からなる厚み80μmの熱可塑性樹脂フィルムを、第2保護フィルムとして、透湿度が16g/m2/24hrであり、環状ポリオレフィン系樹脂からなる厚み23μmの熱可塑性樹脂フィルム(日本ゼオン(株)製の「ZF-14」)を用いた。第1保護フィルムは、紫外線硬化性接着剤((株)ADEKA製の「KR-15P」)を用い、第2保護フィルムは、紫外線硬化性接着剤(株)ADEKA製の「KR-75T」を用いた以外は、実施例2と同様にして、両面保護フィルム付偏光板を作製した。第2保護フィルムを貼合するときのヨウ素系偏光子の水分率は4.8重量%であり、両面保護フィルム付偏光板の視感度補正偏光度Pyは99.994%、視感度補正単体透過率Tyは41.4%であった。
<Example 5>
As the first protective film, a moisture permeability of 63 g / m 2/24 hr or, a thermoplastic resin film having a thickness of 80μm made of an acrylic resin, a second protective film, the moisture permeability is 16g / m 2 / 24hr, A thermoplastic resin film having a thickness of 23 μm made of cyclic polyolefin resin (“ZF-14” manufactured by Nippon Zeon Co., Ltd.) was used. The first protective film uses an ultraviolet curable adhesive (“KR-15P” manufactured by ADEKA), and the second protective film uses “KR-75T” manufactured by an ultraviolet curable adhesive ADEKA. Except having used, it carried out similarly to Example 2, and produced the polarizing plate with a double-sided protective film. When the second protective film is bonded, the moisture content of the iodine-based polarizer is 4.8% by weight, and the visibility correction polarization degree Py of the polarizing plate with the double-sided protection film is 99.994%, and the visibility correction single transmission. The rate Ty was 41.4%.
 <比較例1>
 染色工程最後の乾燥処理(水分率低減工程)の条件を、40℃で60秒間、次いで50℃で60秒間としたこと以外は実施例1と同様にして、両面保護フィルム付偏光板を作製した。第2保護フィルムを貼合するときのヨウ素系偏光子の水分率は、10.7重量%であった。
<Comparative Example 1>
A polarizing plate with a double-sided protective film was produced in the same manner as in Example 1 except that the final drying treatment (moisture content reduction step) was performed at 40 ° C. for 60 seconds and then at 50 ° C. for 60 seconds. . The moisture content of the iodine-type polarizer when bonding the second protective film was 10.7% by weight.
 <比較例2>
 染色工程最後の乾燥処理(水分率低減工程)の条件を、40℃で120秒間としたこと以外は実施例1と同様にして、両面保護フィルム付偏光板を作製した。第2保護フィルムを貼合するときのヨウ素系偏光子の水分率は、12.5重量%であった。
<Comparative example 2>
A polarizing plate with a double-sided protective film was produced in the same manner as in Example 1 except that the final drying treatment (moisture content reduction step) was performed at 40 ° C. for 120 seconds. The moisture content of the iodine-type polarizer when bonding the second protective film was 12.5% by weight.
 <比較例3>
 染色工程最後の乾燥処理(水分率低減工程)後に防湿性フィルムを貼合することなく、25℃55%RHの環境下で約2日間保管してヨウ素系偏光子の水分率を平衡含水率付近まで上昇させ、その後、第1及び第2保護フィルムを貼合したこと以外は実施例2と同様にして、両面保護フィルム付偏光板を作製した。第2保護フィルムを貼合するときのヨウ素系偏光子の水分率は、15.3重量%であった。
<Comparative Example 3>
After the final drying process (moisture content reduction process) in the dyeing process, the moisture content of the iodine-based polarizer is kept near the equilibrium moisture content by storing it for about 2 days in an environment of 25 ° C and 55% RH without laminating a moisture-proof film. Then, a polarizing plate with a double-sided protective film was produced in the same manner as in Example 2 except that the first and second protective films were bonded. The moisture content of the iodine-based polarizer when the second protective film was bonded was 15.3% by weight.
 各実施例及び比較例におけるフィルムの透湿度及びヨウ素系偏光子の水分率は次の方法で測定した。 In the examples and comparative examples, the moisture permeability of the films and the moisture content of the iodine polarizer were measured by the following methods.
 (1)透湿度
 JIS Z 0208-1976「防湿包装材料の透湿度試験方法(カップ法)」に準拠して温度40℃、相対湿度90%での透湿度を測定した。
(1) Moisture Permeability Moisture permeability at a temperature of 40 ° C. and a relative humidity of 90% was measured according to JIS Z 0208-1976 “Method of testing moisture permeability of moisture-proof packaging material (cup method)”.
 (2)ヨウ素系偏光子の水分率
 近赤外水分率計((株)チノー製の「IRMA1100S」)により測定される水分率と乾燥重量法によって得られる水分率との関係を1次式で表す検量線を、水分率が異なる複数のヨウ素系偏光子サンプルについて得られる両水分率からあらかじめ求めておき、近赤外水分率計により測定される水分率を上記検量線を用いて乾燥重量法による水分率に換算して、これをヨウ素系偏光子の水分率とした。なお、乾燥重量法による水分率は、乾燥前の試料の重量をW0、同試料を105℃、1時間の条件で乾燥させたときの重量をW1とするとき、下記式:
 水分率(重量%)=100×(W0-W1)/W0
で定義される。
(2) Moisture content of iodine-based polarizer The relationship between the moisture content measured by a near-infrared moisture meter ("IRMA1100S" manufactured by Chino Co., Ltd.) and the moisture content obtained by the dry weight method is a linear expression. A calibration curve to be expressed is obtained in advance from both moisture percentages obtained for a plurality of iodine-based polarizer samples having different moisture percentages, and the moisture percentage measured by a near-infrared moisture percentage meter is measured by the dry weight method using the calibration curve. In terms of the moisture content by the above, this was used as the moisture content of the iodine polarizer. The moisture content by the dry weight method is expressed by the following formula when the weight of the sample before drying is W0 and the weight when the sample is dried at 105 ° C. for 1 hour is W1:
Moisture content (% by weight) = 100 × (W0−W1) / W0
Defined by
 〔両面保護フィルム付偏光板の耐湿熱性及び耐熱性の評価〕
 (1)耐湿熱性の評価
 実施例1及び2、比較例1~3で作製した両面保護フィルム付偏光板について、65℃90%RHの環境下に500時間静置する耐湿熱性試験後の視感度補正偏光度Pyと試験前のPyとを、吸光光度計(日本分光(株)製の「V7100」)を用いて測定し、両者の差ΔPy(試験前のPy-試験後のPy)から耐湿熱性を評価した。ΔPyの絶対値が小さいほど耐湿熱性が高い。結果を表1に示す。Pyの測定にあたっては、第2保護フィルム側に入射光が照射されるように両面保護フィルム付偏光板サンプルをセットした。なお、耐湿熱性試験後の視感度補正偏光度Pyは、耐湿熱性試験後、23℃55%RHの環境下に約12時間静置してから測定した。
[Evaluation of wet heat resistance and heat resistance of polarizing plate with double-sided protective film]
(1) Evaluation of moisture and heat resistance About the polarizing plates with a double-sided protective film produced in Examples 1 and 2 and Comparative Examples 1 to 3, the visibility after a moisture and heat resistance test of standing in an environment of 65 ° C. and 90% RH for 500 hours The corrected polarization degree Py and the Py before the test were measured using an absorptiometer (“V7100” manufactured by JASCO Corporation), and the moisture resistance was determined from the difference ΔPy between the two (Py before the test−Py after the test). Thermal properties were evaluated. The smaller the absolute value of ΔPy, the higher the heat and moisture resistance. The results are shown in Table 1. In measuring Py, a polarizing plate sample with a double-sided protective film was set so that incident light was irradiated to the second protective film side. In addition, the visibility correction | amendment polarization degree Py after a heat-and-moisture resistance test measured after leaving still in a 23 degreeC55% RH environment for about 12 hours after a heat-and-moisture resistance test.
 耐湿熱性試験(及び下記の耐熱性試験)前のPyは、各実施例及び比較例についていずれも99.995%であった。また、同吸光光度計を用いて測定される視感度補正単体透過率Tyは、各実施例及び比較例についていずれも41.6%であった。 Py before the wet heat resistance test (and the following heat resistance test) was 99.995% for each Example and Comparative Example. Moreover, the visibility-corrected single transmittance Ty measured using the same absorptiometer was 41.6% for each of the examples and the comparative examples.
 (2)耐熱性の評価
 実施例1及び2、比較例1~3で作製した両面保護フィルム付偏光板について、85℃dryの環境下に500時間静置する耐熱性試験を行うことにより、上記耐湿熱性の評価と同様にして、ΔPy(試験前のPy-試験後のPy)から耐熱性を評価した。ΔPyの絶対値が小さいほど耐熱性が高い。結果を表1に示す。
(2) Evaluation of heat resistance The polarizing plate with a double-sided protective film produced in Examples 1 and 2 and Comparative Examples 1 to 3 was subjected to a heat resistance test that was allowed to stand in an environment of 85 ° C. dry for 500 hours. The heat resistance was evaluated from ΔPy (Py before the test−Py after the test) in the same manner as the evaluation of the moist heat resistance. The smaller the absolute value of ΔPy, the higher the heat resistance. The results are shown in Table 1.
 (3)促進条件下における耐湿熱性の評価
 実施例3~5で作製した両面保護フィルム付偏光板について、80℃、90%RHの環境下に48時間静置する耐湿熱性試験を、前記(1)耐湿熱性の評価と同様の方法で行った。結果を表2に示す。
(3) Evaluation of moisture and heat resistance under accelerated conditions The polarizing plate with double-sided protective film produced in Examples 3 to 5 was subjected to the moisture and heat resistance test in which the plate was allowed to stand for 48 hours in an environment of 80 ° C. and 90% RH. ) It was performed by the same method as the evaluation of heat and humidity resistance. The results are shown in Table 2.
 (4)促進条件下における耐熱性の評価
 実施例3~5で作製した両面保護フィルム付偏光板について、105℃、dryの環境下に48時間静置する耐熱性試験を、前記(2)耐熱性の評価と同様の方法で行った。結果を表2に示す。
(4) Evaluation of heat resistance under accelerated conditions The polarizing plate with a double-sided protective film produced in Examples 3 to 5 was subjected to the heat resistance test of standing at 105 ° C. in a dry environment for 48 hours. The same method as the evaluation of sex was performed. The results are shown in Table 2.
 また、耐熱性試験後の両面保護フィルム付偏光板について、光漏れ(赤変)の程度を目視で確認した。具体的には、耐熱性試験後の両面保護フィルム付偏光板から10cm×20cmの試料片を2つ切り出し、これらの試料をガラス板の両面に粘着剤を用いて貼合した。この際、第2保護フィルム側がガラス板側になるようにし、かつ、両面に配置した試料片はクロスニコルの位置関係になるようにした。そして、暗室にて一方の偏光板側からバックライトを当て、下記の評価基準に従って赤変の目視評価を行った。結果を表1及び表2に示す。 Further, the degree of light leakage (redness) was visually confirmed for the polarizing plate with a double-sided protective film after the heat resistance test. Specifically, two sample pieces of 10 cm × 20 cm were cut out from the polarizing plate with a double-sided protective film after the heat resistance test, and these samples were bonded to both surfaces of the glass plate using an adhesive. At this time, the second protective film side was set to the glass plate side, and the sample pieces arranged on both surfaces were set to have a crossed Nicols positional relationship. And the backlight was applied from the one polarizing plate side in the dark room, and the visual evaluation of red discoloration was performed according to the following evaluation criteria. The results are shown in Tables 1 and 2.
 A:真っ黒の状態を保ち、目視で赤変が認識できない、
 B:明らかな赤変が認められる。
A: The black state is maintained and redness cannot be recognized visually.
B: Clear red discoloration is observed.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
 5 ヨウ素系偏光子、6 ポリビニルアルコール系樹脂層、6’ 延伸されたポリビニルアルコール系樹脂層、10 第1保護フィルム、15 第1接着剤層、20 第2保護フィルム、25 第2接着剤層、30 基材フィルム、30’ 延伸された基材フィルム、100 片面保護フィルム付偏光板、200 積層フィルム、300 延伸フィルム、400 偏光性積層フィルム、500 多層フィルム、600 両面保護フィルム付偏光板。 5 iodine polarizer, 6 polyvinyl alcohol resin layer, 6 ′ stretched polyvinyl alcohol resin layer, 10 first protective film, 15 first adhesive layer, 20 second protective film, 25 second adhesive layer, 30 base film, 30 ′ stretched base film, 100 polarizing plate with single-sided protective film, 200 laminated film, 300 stretched film, 400 polarizing laminated film, 500 multilayer film, 600 polarizing plate with double-sided protective film.

Claims (8)

  1.  基材フィルム、ヨウ素系偏光子及び第1保護フィルムをこの順で含む多層フィルムから基材フィルムを剥離除去して、片面保護フィルム付偏光板を得る工程と、
     前記片面保護フィルム付偏光板におけるヨウ素系偏光子の外面に第2保護フィルムを貼合して、両面保護フィルム付偏光板を得る工程と、
    を含み、
     前記第1保護フィルム及び前記第2保護フィルムは、透湿度150g/m2/24hr以下の熱可塑性樹脂フィルムであり、
     前記第2保護フィルムを貼合するときの前記ヨウ素系偏光子の水分率が8重量%未満である、両面保護フィルム付偏光板の製造方法。
    Removing the base film from the multilayer film including the base film, the iodine-based polarizer and the first protective film in this order to obtain a polarizing plate with a single-side protective film;
    Bonding a second protective film to the outer surface of the iodine-based polarizer in the polarizing plate with a single-sided protective film to obtain a polarizing plate with a double-sided protective film;
    Including
    The first protective film and the second protective film is a thermoplastic film of less moisture permeability 150 g / m 2/24 hr or,
    The manufacturing method of the polarizing plate with a double-sided protective film whose moisture content of the said iodine type polarizer when bonding a said 2nd protective film is less than 8 weight%.
  2.  活性エネルギー線硬化性接着剤を用いて前記第2保護フィルムを前記ヨウ素系偏光子の外面に貼合する、請求項1に記載の製造方法。 The manufacturing method according to claim 1, wherein the second protective film is bonded to the outer surface of the iodine-based polarizer using an active energy ray-curable adhesive.
  3.  前記ヨウ素系偏光子は、その厚みが10μm以下である、請求項1又は2に記載の製造方法。 The manufacturing method according to claim 1, wherein the iodine-based polarizer has a thickness of 10 μm or less.
  4.  ヨウ素系偏光子及びその片面に積層される第1保護フィルムを含む片面保護フィルム付偏光板におけるヨウ素系偏光子外面に第2保護フィルムを貼合して、両面保護フィルム付偏光板を得る工程を含み、
     前記第1保護フィルム及び前記第2保護フィルムは、透湿度150g/m2/24hr以下の熱可塑性樹脂フィルムであり、
     前記第2保護フィルムを貼合するときの前記ヨウ素系偏光子の水分率が8重量%未満である、両面保護フィルム付偏光板の製造方法。
    A step of obtaining a polarizing plate with a double-sided protective film by laminating a second protective film on the outer surface of the iodine-based polarizer in the polarizing plate with a single-sided protective film including the iodine-type polarizer and the first protective film laminated on one side thereof. Including
    The first protective film and the second protective film is a thermoplastic film of less moisture permeability 150 g / m 2/24 hr or,
    The manufacturing method of the polarizing plate with a double-sided protective film whose moisture content of the said iodine type polarizer when bonding a said 2nd protective film is less than 8 weight%.
  5.  活性エネルギー線硬化性接着剤を用いて前記第2保護フィルムを前記ヨウ素系偏光子の外面に貼合する、請求項4に記載の製造方法。 The manufacturing method according to claim 4, wherein the second protective film is bonded to an outer surface of the iodine-based polarizer using an active energy ray-curable adhesive.
  6.  前記ヨウ素系偏光子は、その厚みが10μm以下である、請求項4又は5に記載の製造方法。 The manufacturing method according to claim 4 or 5, wherein the iodine polarizer has a thickness of 10 µm or less.
  7.  ヨウ素系偏光子とその両面に積層される保護フィルムとを含み、
     両面に積層される保護フィルムはいずれも、透湿度150g/m2/24hr以下の熱可塑性樹脂フィルムであり、
     前記ヨウ素系偏光子の水分率が8重量%未満である、両面保護フィルム付偏光板。
    Including an iodine-based polarizer and a protective film laminated on both sides thereof,
    Any protective film to be laminated on both sides, a thermoplastic resin film of less moisture permeability 150g / m 2 / 24hr,
    A polarizing plate with a double-sided protective film, wherein the iodine polarizer has a moisture content of less than 8% by weight.
  8.  前記ヨウ素系偏光子は、その厚みが10μm以下である、請求項7に記載の両面保護フィルム付偏光板。 The polarizing plate with a double-sided protective film according to claim 7, wherein the iodine-based polarizer has a thickness of 10 μm or less.
PCT/JP2015/067316 2014-07-04 2015-06-16 Method for producing polarizing plate having protective films on both surfaces thereof WO2016002504A1 (en)

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Cited By (6)

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JP6306675B1 (en) * 2016-11-28 2018-04-04 住友化学株式会社 Method for producing polarizing laminated film with protective film and method for producing polarizing plate
WO2020116074A1 (en) * 2018-12-07 2020-06-11 住友化学株式会社 Polarizing plate and display device
EP3761084A4 (en) * 2018-02-28 2021-11-17 Nitto Denko Corporation Polarizing film laminate for powered vehicle, and optical display panel in which said polarizing film laminate is used

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JP6321999B2 (en) * 2014-03-06 2018-05-09 住友化学株式会社 Manufacturing method of polarizing plate
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59159109A (en) * 1983-03-01 1984-09-08 Sumitomo Chem Co Ltd Polarizing plate having excellent durability
JP2011090336A (en) * 2000-07-10 2011-05-06 Nitto Denko Corp Method of producing polarizing plate
JP2014012819A (en) * 2012-06-08 2014-01-23 Nitto Denko Corp Active energy ray-curable adhesive composition, polarizing film and production method of the same, and optical film and image display device

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001343521A (en) * 2000-05-31 2001-12-14 Sumitomo Chem Co Ltd Polarizing plate and method for manufacturing the same
JP2002090546A (en) * 2000-07-10 2002-03-27 Nitto Denko Corp Polarizing plate and method for manufacturing the same
JP4306270B2 (en) 2003-02-12 2009-07-29 住友化学株式会社 Polarizing plate, manufacturing method thereof, optical member, and liquid crystal display device
JP5502023B2 (en) * 2010-09-03 2014-05-28 日東電工株式会社 Method for producing optical film laminate roll having polarizing film
JP4691205B1 (en) * 2010-09-03 2011-06-01 日東電工株式会社 Method for producing optical film laminate including thin high-performance polarizing film
JP6203143B2 (en) * 2014-07-22 2017-09-27 住友化学株式会社 Manufacturing method of polarizing plate
JP7240400B2 (en) * 2019-01-25 2023-03-15 杉金光電(蘇州)有限公司 Method for producing polarizing plate and adhesive composition for polarizing plate

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59159109A (en) * 1983-03-01 1984-09-08 Sumitomo Chem Co Ltd Polarizing plate having excellent durability
JP2011090336A (en) * 2000-07-10 2011-05-06 Nitto Denko Corp Method of producing polarizing plate
JP2014012819A (en) * 2012-06-08 2014-01-23 Nitto Denko Corp Active energy ray-curable adhesive composition, polarizing film and production method of the same, and optical film and image display device

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CN108121027A (en) * 2016-11-28 2018-06-05 住友化学株式会社 The manufacturing method of polarizability stacked film and the manufacturing method of polarization plates with protective film
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