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 PDFInfo
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- 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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- protective film
- iodine
- film
- polarizing plate
- polarizer
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising 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.
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Abstract
Description
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%.
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%.
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.
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.
(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).
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.
(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
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
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.
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
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
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
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
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
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
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
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
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
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
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
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
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
(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.
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(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.
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.
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.
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.
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%.
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%.
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%.
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.
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.
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.
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)”.
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
(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.
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.
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.
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.
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.
Claims (8)
- 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%. - 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.
- 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.
- 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%. - 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.
- 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.
- 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. - 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.
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