JP6339621B2 - Production method of polarizing laminated film and polarizing plate - Google Patents

Production method of polarizing laminated film and polarizing plate Download PDF

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JP6339621B2
JP6339621B2 JP2016079398A JP2016079398A JP6339621B2 JP 6339621 B2 JP6339621 B2 JP 6339621B2 JP 2016079398 A JP2016079398 A JP 2016079398A JP 2016079398 A JP2016079398 A JP 2016079398A JP 6339621 B2 JP6339621 B2 JP 6339621B2
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film
resin
layer
polyvinyl alcohol
drying
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JP2016136281A (en
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雄一朗 九内
雄一朗 九内
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住友化学株式会社
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B29C55/023Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets using multilayered plates or sheets
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B29C55/04Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique
    • B29C55/06Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique parallel with the direction of feed
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B29C55/04Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique
    • B29C55/06Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique parallel with the direction of feed
    • B29C55/065Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique parallel with the direction of feed in several stretching steps
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B5/00Optical elements other than lenses
    • G02B5/30Polarising elements
    • G02B5/3025Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29KINDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2029/00Use of polyvinylalcohols, polyvinylethers, polyvinylaldehydes, polyvinylketones or polyvinylketals or derivatives thereof as moulding material
    • B29K2029/04PVOH, i.e. polyvinyl alcohol
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29KINDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2995/00Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
    • B29K2995/0018Properties of moulding materials, reinforcements, fillers, preformed parts or moulds having particular optical properties, e.g. fluorescent or phosphorescent
    • B29K2995/0034Polarising

Description

  The present invention relates to a polarizing laminate film and a method for producing a polarizing plate.
  A polarizing plate is widely used as a polarization supplying element in a display device such as a liquid crystal display device. Conventionally, a polarizing plate made of a polyvinyl alcohol-based resin and a protective film such as triacetyl cellulose are used as the polarizing plate. The polarizer layer (polarizing film) is required to have high optical performance, and in recent years, with the development of liquid crystal display devices such as notebook personal computers and mobile phones, reduction in thickness and weight is required.
  As an example of a manufacturing method of a polarizing plate, after a film made of a polyvinyl alcohol resin is stretched alone or while being stretched, a polarizing film is produced by performing a dyeing treatment or a crosslinking treatment, and this is laminated on a protective film or the like. Thus, a method for manufacturing a polarizing plate is known (see, for example, Patent Document 1).
  As another example of the manufacturing method of a polarizing plate, after apply | coating the solution containing a polyvinyl alcohol-type resin on the surface of a base film and providing a resin layer, the laminated | multilayer film which consists of a base film and a resin layer are extended | stretched, then A method has been proposed in which a polarizer layer is formed from a resin layer by dyeing to obtain a polarizing laminated film having the polarizer layer (see, for example, Patent Document 2). The method of using this as a polarizing plate as it is, or using the thing which peeled the base film after bonding a protective film to this film as a polarizing plate is disclosed.
  As another example of the method for producing a polarizing plate, a protective film resin and a polyvinyl alcohol-based resin are coextruded to produce a laminated film, and the laminated film is stretched and then dyed to obtain a polarizer layer and a protective film There has been proposed a method of obtaining a polarizing plate made of (see, for example, Patent Document 3).
Japanese Patent Laid-Open No. 11-49878 JP 2000-338329 A JP 2009-258218 A
  However, in the method of producing a polarizing film by subjecting a film made of a polyvinyl alcohol resin alone to stretching, dyeing, and crosslinking, it is difficult to handle a thin film of 50 μm or less because breakage or wrinkles are likely to occur. Therefore, it is difficult to realize a thin polarizing film.
  In the method of providing a resin layer by applying a solution containing a polyvinyl alcohol resin on the surface of the base film, the resin layer is easily shrunk due to drying shrinkage of the solution containing the polyvinyl alcohol resin, so that both ends of the base film are A phenomenon of warping to the resin layer side may occur, and if the base film with the resin layer is continuously flowed in this state, the end of the base film is folded in the drying furnace or at the outlet of the drying furnace. May cause malfunctions.
  In the method of producing a laminated film by co-extrusion of a protective film resin and a polyvinyl alcohol resin, since the extrusion is usually performed by melting the polyvinyl alcohol resin together with a solvent, the end of the base film is caused by drying shrinkage as described above. There may be a problem that the part is folded.
  Then, the objective of this invention is providing the method of manufacturing the polarizing laminated film and polarizing plate which have a thin polarizer layer, without causing the malfunction that the edge part of a base film bends.
The present invention is a method for producing a polarizing laminate film comprising a base film and a polarizer layer formed on one surface of the base film,
A resin film laminating step in which a laminated film is obtained by laminating a resin film made of a polyvinyl alcohol resin having a thickness of 50 μm or less on one surface of the base film;
A stretching step for uniaxially stretching the laminated film;
A method for producing a polarizing laminated film comprising: a dyeing step of forming a polarizer layer by dyeing the resin film of a uniaxially stretched film with a dichroic dye in this order.
  In the resin film bonding step, for example, the resin film is bonded to one surface of the base film via an adhesive layer or an adhesive layer.
  In the resin film bonding step, the thickness of the resin film is preferably 15 μm or more.
The resin film used in the resin film bonding step is preferably
A resin layer forming step of forming a resin layer comprising a polyvinyl alcohol resin on a support;
A first drying step of drying the resin layer formed on the support;
A resin layer separation step of separating the dried resin layer from the support to obtain the resin layer;
It is the resin film manufactured by the manufacturing method which includes the 2nd drying process which dries the peeled resin layer at the drying temperature higher than the temperature in a 1st drying process in this order.
Further, the present invention is a method for producing a polarizing plate comprising a polarizer layer and a protective film formed on one surface of the polarizer layer,
After producing a polarizing laminate film by the production method of the present invention,
A protective film laminating step of laminating a protective film on the surface of the polarizer layer in the polarizing laminated film opposite to the surface on the substrate film side;
A base film peeling step for peeling the base film from the polarizing laminated film in this order.
  According to this invention, the polarizing laminated film and polarizing plate which have a thin polarizer layer can be manufactured, without the edge part of a base film folding in a manufacturing process.
It is a flowchart which shows one Embodiment of the manufacturing method of the light-polarizing laminated film of this invention. It is a flowchart which shows one Embodiment of the manufacturing method of the polarizing plate of this invention. It is a flowchart which shows one Embodiment of the manufacturing method of a polyvinyl alcohol-type resin film.
  Hereinafter, with reference to the drawings, preferred embodiments of a method for producing a polarizing laminate film and a method for producing a polarizing plate according to the present invention will be described in detail.
[Method for producing polarizing laminated film]
FIG. 1 is a flowchart showing an embodiment of a method for producing a polarizing laminated film according to the present invention. The polarizing laminated film manufactured in this embodiment includes a base film and a polarizer layer formed on one surface of the base film. In the manufacturing method of the light-polarizing laminated film of this embodiment, the resin film bonding process (S10) which bonds the resin film which consists of polyvinyl alcohol-type resin to the one surface of a base film, and obtains a laminated film, and the said lamination | stacking A stretching step (S20) for uniaxially stretching the film and a staining step (S30) for forming a polarizer layer by staining the resin film of the laminated film with a dichroic dye are sequentially performed.
  In the present specification, a laminate in which a resin film made of a polyvinyl alcohol resin (hereinafter also referred to as “polyvinyl alcohol resin film”) is bonded to one surface of a base film is referred to as a “laminated film”, a polarizer. A polyvinyl alcohol-based resin film having a function as a “polarizer layer” and a laminate having a polarizer layer on one surface of a substrate film are referred to as a “polarizing laminate film”. And the laminated body provided with the protective film on one surface of a polarizer layer is called "polarizing plate."
  By the above production method, a polarizing laminated film having a sufficient polarizing performance, for example, a polarizer layer having a thickness of 25 μm or less can be obtained on the base film. The thickness of the polarizer layer of the polarizing laminate film obtained by the above production method is preferably 25 μm or less, more preferably 20 μm or less. As will be described later, this polarizing laminated film can also be used as an intermediate product for transferring a polarizer layer to a protective film, and when the substrate film has the function of a protective film, this polarizing film The laminated film can be used as a polarizing plate as it is.
[Production method of polarizing plate]
FIG. 2 is a flowchart showing an embodiment of a method for producing a polarizing plate according to the present invention. The polarizing plate produced in the present embodiment includes a polarizer layer and a protective film formed on one surface of the polarizer layer. The manufacturing method of the polarizing plate of the present embodiment includes a resin film bonding step (S10) in which a polyvinyl alcohol resin film is bonded to one surface of a base film to obtain a laminated film, and the laminated film is uniaxially stretched. After carrying out an extending process (S20) and the dyeing process (S30) which dyes the polyvinyl alcohol system resin film of the lamination film with a dichroic dye, and forms a polarizer layer in order, and obtained a polarizing lamination film , A protective film laminating step (S40) for laminating a protective film on the surface of the polarizer layer opposite to the surface of the polarizer layer on the base film side, and peeling the base film from the polarizing laminate film It has a base film peeling process (S50) in this order.
  By the above production method, a polarizing plate having a sufficient polarization performance on the protective film, for example, a polarizer layer having a thickness of 25 μm or less can be obtained. The thickness of the polarizer layer of the polarizing plate obtained by the above production method is preferably 25 μm or less, more preferably 20 μm or less. This polarizing plate can be used, for example, by being bonded to another optical film or a liquid crystal cell via a pressure-sensitive adhesive.
  Hereafter, each process of S10-S50 in FIG. 1 and FIG. 2 is demonstrated in detail. Each process of S10 to S30 in FIGS. 1 and 2 is the same process.
<Resin film bonding step (S10)>
A polyvinyl alcohol-based resin film is bonded to one surface of the base film. The bonding method of the base film and the polyvinyl alcohol-based resin film is not particularly limited as long as it does not peel off even after the subsequent stretching step (S20) and dyeing step (S30). For example, a pressure-sensitive adhesive layer or an adhesive layer is formed on the bonding surface of a polyvinyl alcohol-based resin film and / or a substrate film, and both are bonded via the pressure-sensitive adhesive layer or the adhesive layer.
(Polyvinyl alcohol resin film)
The thickness of the polyvinyl alcohol-type resin film used in a resin film bonding process shall be 50 micrometers or less. The polyvinyl alcohol-based resin film forms a polarizer layer through a subsequent stretching step and a dyeing step. The polyvinyl alcohol-based resin film in the resin film bonding step (S10), that is, the polyvinyl alcohol-based resin before stretching. When the thickness of the film exceeds 50 μm, since the stretching process and the dyeing process can be handled without bonding to the base film as in the present invention, the merit of the present invention is small. Moreover, when the thickness of a polyvinyl alcohol-type resin film exceeds 50 micrometers, it may be difficult to form the thickness of a polarizer layer into a thin film of 25 micrometers or less. Furthermore, the thickness of the polyvinyl alcohol-based resin film (before stretching) is preferably 10 μm or more, more preferably 15 μm or more. When the thickness of the polyvinyl alcohol resin film is less than 10 μm, it is difficult to obtain the polyvinyl alcohol resin film alone. The thickness of the polyvinyl alcohol resin film is more preferably 15 to 45 μm.
  As a polyvinyl alcohol-type resin which forms a polyvinyl alcohol-type resin film, what saponified polyvinyl acetate-type resin can be used. Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers with other monomers copolymerizable with vinyl acetate. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.
  The polyvinyl alcohol resin is preferably a completely saponified product. The range of the saponification degree is preferably 80.0 mol% to 100.0 mol%, more preferably 90.0 mol% to 100 mol%, and further preferably 94.0 mol% to 100 mol%. Most preferred are those in the mol% range. If the degree of saponification is less than 80.0 mol%, there is a problem that the water resistance and heat-and-moisture resistance after forming the polarizer layer are remarkably inferior.
  The saponification degree as used herein is a unit ratio (mol%) representing the ratio of the acetate group contained in the polyvinyl acetate resin, which is a raw material for the polyvinyl alcohol resin, to a hydroxyl group by the saponification step. Is a numerical value defined by the following formula. It can be determined by the method defined in JIS K 6726 (1994).
Saponification degree (mol%) = (number of hydroxyl groups) ÷ (number of hydroxyl groups + number of acetate groups) × 100
The higher the degree of saponification, the higher the proportion of hydroxyl groups, that is, the lower the proportion of acetate groups that inhibit crystallization.
  The polyvinyl alcohol-based resin may be 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, acrylamide, and the like can be used. The proportion of modification is preferably less than 30 mol%, and more preferably less than 10%. When modification exceeding 30 mol% is performed, it becomes difficult to adsorb the dichroic dye, resulting in a problem that the polarization performance is lowered.
  The average degree of polymerization of the polyvinyl alcohol-based resin is not particularly limited, but is preferably 100 to 10,000, more preferably 1500 to 8000, and most preferably 2000 to 5000. The average degree of polymerization here is also a numerical value determined by a method defined by JIS K 6726 (1994).
  Examples of the polyvinyl alcohol resin having such characteristics include PVA124 (degree of saponification: 98.0 to 99.0 mol%) and PVA117 (degree of saponification: 98.0 to 99.0) manufactured by Kuraray Co., Ltd. Mol%), PVA624 (degree of saponification: 95.0 to 96.0 mol%) and PVA617 (degree of saponification: 94.5 to 95.5 mol%); for example, AH- manufactured by Nippon Synthetic Chemical Industry Co., Ltd. 26 (degree of saponification: 97.0-98.8 mol%), AH-22 (degree of saponification: 97.5-98.5 mol%), NH-18 (degree of saponification: 98.0-99. 0 mol%), and N-300 (degree of saponification: 98.0 to 99.0 mol%); for example, JC-33 (degree of saponification: 99.0 mol% or more) of Nippon Vinegar Pival Co., Ltd. , JM-33 (degree of saponification: 93.5 to 95.5 mol%), JM 26 (degree of saponification: 95.5-97.5 mol%), JP-45 (degree of saponification: 86.5-89.5 mol%), JF-17 (degree of saponification: 98.0-99. 0 mol%), JF-17L (degree of saponification: 98.0 to 99.0 mol%), JF-20 (degree of saponification: 98.0 to 99.0 mol%), and the like. Can be suitably used in the formation of the polyvinyl alcohol-based resin film of the present invention.
  A polyvinyl alcohol resin film is formed by forming the polyvinyl alcohol resin as described above. The method for forming the polyvinyl alcohol-based resin film is not particularly limited. For example, a solvent casting method in which a polyvinyl alcohol resin solution is applied on a support and dried, or a melt extrusion method in which a polyvinyl alcohol resin containing water is melt-kneaded and extruded onto a support by an extruder, And a gel film forming method in which an aqueous polyvinyl alcohol resin solution is discharged into a poor solvent. Among these, a cast method or a melt extrusion method is preferable because a more transparent film can be obtained.
  Hereinafter, preferable embodiment of the manufacturing method of a polyvinyl alcohol-type resin film is described. FIG. 3 shows a flowchart of the method for producing the polyvinyl alcohol-based resin film of the present embodiment. In the present embodiment, a resin layer forming step (S110) for forming a resin layer made of a polyvinyl alcohol-based resin on a support, a first drying step (S120) for drying the resin layer, and the resin layer A resin layer separation step (S130) for separating the substrate from the support to obtain the resin layer, and a second drying step (S140) for drying the resin layer at a temperature higher than the temperature in the first drying step in this order. carry out.
  Examples of the support herein include release films, stainless steel belts, and chill rolls. Examples of the method for forming the resin layer on the support in the resin layer forming step (S110) include the solvent casting method and the melt extrusion method described above. For example, there is a solvent casting method in which a polyvinyl alcohol resin solution obtained by dissolving polyvinyl alcohol resin powder in a good solvent is applied on one surface of a support, and the solvent is evaporated and dried. Is preferred. By forming the polyvinyl alcohol resin layer in this way, it becomes possible to form a polyvinyl alcohol resin layer having a thickness of 10 to 50 μm.
  As a method of coating a polyvinyl alcohol resin solution on a support, roll coating methods such as wire bar coating method, reverse coating method and gravure coating, die coating method, comma coater method, lip coating method, spin coating method, screen Known methods such as a coating method, a fountain coating method, a dipping method, and a spray method can be appropriately selected and employed.
  The polyvinyl alcohol resin solution used in these methods can be obtained, for example, by dissolving the polyvinyl alcohol resin in water heated to 80 to 90 ° C. The solid content concentration of the polyvinyl alcohol-based resin is preferably in the range of 6 wt% to 50 wt%. When the concentration of the solid content is less than 6 wt%, the viscosity becomes too low and the fluidity at the time of forming the resin layer becomes too high, and it becomes difficult to obtain a uniform film. On the other hand, if the concentration of the solid content exceeds 50 wt%, the viscosity becomes too high and the fluidity at the time of forming the resin layer becomes low, so that film formation becomes difficult.
  A plasticizer can be added to the polyvinyl alcohol resin solution. Of these, polyhydric alcohols are preferably used, and examples thereof include ethylene glycol, glycerin, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and trimethylolpropane. A plurality may be combined. In particular, ethylene glycol and glycerin are preferably used. Moreover, if necessary, a blocking agent such as a surfactant can be used in combination.
After the resin layer forming step (S110), in the first drying step (S120), the resin layer formed on the support is dried at a low temperature, usually 60 ° C. or less, to the extent that it can be peeled off from the support. . The degree to which the film can be peeled from the support is such that the coating liquid becomes solid to some extent and can be peeled off as a film. If the moisture content is usually dried to 30% by weight or less, the entire film can be peeled stably. Drying to 20% by weight or less is preferable because it can be more easily peeled off. The moisture content mentioned here indicates the amount of water obtained by the dry weight method, and can be obtained by the following method.
-The PVA film after peeling is allowed to stand at room temperature (approximately 25 ° C, 55% RH) for 30 minutes or more, and then the film weight is measured.
-Then, after taking out after drying for 60 minutes at 105 degreeC, it is left to stand for several minutes until the film temperature returns to normal temperature.
・ After a few minutes, re-measure the film weight.
・ Substitute the obtained value into the following formula.
Moisture content = (weight before drying−weight after drying) / weight before drying × 100 (weight / weight%)
As a specific method for drying the resin layer formed on the support to such an extent that it can be peeled off from the support, for example, in actual production, the drying conditions that reach this peelable state are determined in advance through preliminary experiments. It is preferable to carry out under the conditions. For example, it is preferable to dry in the temperature range of 40 to 60 ° C. for 1 to 30 minutes, and drying at 50 ° C. for about 3 to 20 minutes is more preferable. In the first drying step (S120), drying shrinkage in the resin layer is less likely to occur by drying at a low temperature and drying the resin layer to such an extent that it can be peeled off from the support instead of drying completely. It is also possible to prevent the curling of the end of the body.
  Next, in the resin layer separation step (S130), the resin layer produced in the first drying step is peeled from the support to obtain a resin layer. Then, in the second drying step (S140), the resin layer peeled from the support is dried. In the second drying step (S140), the resin layer is sufficiently dried. Therefore, drying is performed at a drying temperature that is higher than that in the first drying step. The high temperature here is usually 150 ° C. or lower, preferably 120 ° C. or lower, more preferably 100 ° C. or lower, preferably 60 ° C. or higher, more preferably 70 ° C. or higher. There are various drying methods such as a method of blowing hot air, a method of contacting with a hot roll, and a method of heating with an IR heater, all of which can be suitably used. The drying temperature in the first drying step and the second drying step means the atmospheric temperature in the drying furnace in the case of a drying facility provided with a drying furnace such as a method of blowing hot air or an IR heater. In the case of contact-type drying equipment such as a roll, it means the surface temperature of the hot roll. A polyvinyl alcohol-type resin film is manufactured through the above process.
  The polyvinyl alcohol-based resin film produced by the method of this embodiment is a good one with curling suppressed.
(Base film)
As the resin used for the base film, for example, thermoplastic resins excellent in transparency, mechanical strength, thermal stability, stretchability, etc. are used, and an appropriate resin is selected according to their glass transition temperature Tg or melting point Tm. You can choose. It is preferable to use a base film that can be stretched in a temperature range suitable for stretching a polyvinyl alcohol-based resin film laminated thereon.
  Specific examples of thermoplastic resins include polyolefin resins, polyester resins, cyclic polyolefin resins (norbornene resins), (meth) acrylic resins, cellulose ester resins, polycarbonate resins, polyvinyl alcohol resins, vinyl acetate. Resin, polyarylate resin, polystyrene resin, polyethersulfone resin, polysulfone resin, polyamide resin, polyimide resin, and mixtures and copolymers thereof.
  The base film may be a film made of only one kind of the above-mentioned resin, or may be a film made by blending two or more kinds of resins. The base film may be a single layer film or a multilayer film.
  Examples of the polyolefin resin include polyethylene and polypropylene, which are preferable because they can be stably stretched at a high magnification. Moreover, an ethylene-polypropylene copolymer obtained by copolymerizing propylene with ethylene can also be used. Copolymerization can be performed with other types of monomers, and examples of other types of monomers copolymerizable with propylene include ethylene and α-olefins. As the α-olefin, an α-olefin having 4 or more carbon atoms is preferably used, and more preferably an α-olefin having 4 to 10 carbon atoms. Specific examples of the α-olefin having 4 to 10 carbon atoms include linear monoolefins such as 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene and 1-decene; Branched monoolefins such as 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene; vinylcyclohexane and the like. The copolymer of propylene and other monomers copolymerizable therewith may be a random copolymer or a block copolymer. The content of the structural unit derived from the other monomer in the copolymer is determined by infrared (IR) spectrum according to the method described on page 616 of “Polymer Analysis Handbook” (1995, published by Kinokuniya). It can be obtained by measuring.
  Among the above, propylene-based resins constituting the propylene-based resin film include propylene homopolymer, propylene-ethylene random copolymer, propylene-1-butene random copolymer, and propylene-ethylene-1-butene. Random copolymers are preferably used.
  The stereoregularity of the propylene resin constituting the propylene resin film is preferably substantially isotactic or syndiotactic. A propylene-based resin film made of a propylene-based resin having substantially isotactic or syndiotactic stereoregularity has relatively good handleability and excellent mechanical strength in a high-temperature environment.
  The polyester resin is a polymer having an ester bond and is mainly a polycondensate of a polyvalent carboxylic acid and a polyhydric alcohol. As the polyvalent carboxylic acid used, divalent dicarboxylic acid is mainly used, and examples thereof include isophthalic acid, terephthalic acid, dimethyl terephthalate, and dimethyl naphthalenedicarboxylate. In addition, divalent diol is mainly used as the polyhydric alcohol used, and examples thereof include propanediol, butanediol, neopentyl glycol, and cyclohexanedimethanol. Specific examples of the resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexane dimethyl terephthalate, polycyclohexane dimethyl naphthalate, and the like. . These blend resins and copolymers can also be suitably used.
  As the cyclic polyolefin resin, a norbornene resin is preferably used. Cyclic polyolefin resin is a general term for resins that are polymerized using cyclic olefin as a polymerization unit, and is described in, for example, JP-A-1-240517, JP-A-3-14882, JP-A-3-122137, and the like. Resin. Specific examples include ring-opening (co) polymers of cyclic olefins, addition polymers of cyclic olefins, cyclic olefins and α-olefins such as ethylene and propylene (typically random copolymers), And graft polymers obtained by modifying them with an unsaturated carboxylic acid or a derivative thereof, and hydrides thereof. Specific examples of the cyclic olefin include norbornene monomers.
  Various products are commercially available as cyclic polyolefin resins. As specific examples, Topas (registered trademark) (manufactured by Ticona), Arton (registered trademark) (manufactured by JSR Corporation), ZEONOR (registered trademark) (manufactured by Nippon Zeon Corporation), ZEONEX (ZEONEX) (Registered trademark) (manufactured by ZEON CORPORATION) and Apel (registered trademark) (manufactured by Mitsui Chemicals, Inc.).
  Any appropriate (meth) acrylic resin can be adopted as the (meth) acrylic resin. For example, poly (meth) acrylic acid ester such as polymethyl methacrylate, methyl methacrylate- (meth) acrylic acid copolymer, methyl methacrylate- (meth) acrylic acid ester copolymer, methyl methacrylate-acrylic acid ester -(Meth) acrylic acid copolymer, (meth) acrylic acid methyl-styrene copolymer (MS resin, etc.), polymer having an alicyclic hydrocarbon group (for example, methyl methacrylate-cyclohexyl methacrylate copolymer) And methyl methacrylate- (meth) acrylate norbornyl copolymer). Preferably, C1-6 alkyl poly (meth) acrylates, such as poly (meth) acrylate methyl, are mentioned. More preferably, as the (meth) acrylic resin, a methyl methacrylate-based resin containing methyl methacrylate as a main component (50 to 100% by weight, preferably 70 to 100% by weight) is used.
  The cellulose ester resin is an ester of cellulose and a fatty acid. Specific examples of the cellulose ester resin include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. Moreover, these copolymers and those obtained by modifying a part of the hydroxyl group with other types of substituents are also included. Among these, cellulose triacetate is particularly preferable. Many products of cellulose triacetate are commercially available, which is advantageous in terms of availability and cost. Examples of commercially available products of cellulose triacetate include Fujitac (registered trademark) TD80 (manufactured by Fuji Film Co., Ltd.), Fujitac (registered trademark) TD80UF (manufactured by Fuji Film Co., Ltd.), Fujitac (registered trademark) TD80UZ (Fuji Film ( Co., Ltd.), Fujitac (registered trademark) TD40UZ (Fuji Film Co., Ltd.), KC8UX2M (Konica Minolta Opto Co., Ltd.), KC4UY (Konica Minolta Opto Co., Ltd.), and the like.
  The polycarbonate resin is an engineering plastic made of a polymer in which monomer units are bonded via a carbonate group, and is a resin having high impact resistance, heat resistance, and flame retardancy. Moreover, since it has high transparency, it is suitably used in optical applications. In optical applications, resins called modified polycarbonates in which the polymer skeleton is modified in order to lower the photoelastic coefficient, copolymerized polycarbonates with improved wavelength dependency, and the like are commercially available and can be suitably used. Such polycarbonate resins are widely commercially available. For example, Panlite (registered trademark) (Teijin Chemicals Ltd.), Iupilon (registered trademark) (Mitsubishi Engineering Plastics), SD Polyca (registered trademark) (Sumitomo) Dow Co., Ltd.), Caliber (registered trademark) (Dow Chemical Co., Ltd.) and the like.
  Arbitrary appropriate additives other than said thermoplastic resin may be added to the base film. Examples of such additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, and coloring agents. . The content of the thermoplastic resin exemplified above in the base film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, and particularly preferably 70 to 97%. % By weight. This is because, if the content of the thermoplastic resin in the base film is less than 50% by weight, the high transparency inherent in the thermoplastic resin may not be sufficiently exhibited.
  Although the thickness of the base film before stretching can be determined as appropriate, in general, from the viewpoint of workability such as strength and handleability, it is preferably 1 to 500 μm, more preferably 1 to 300 μm, and still more preferably 5 to 5 μm. 200 μm, most preferably 5 to 150 μm.
  The base film may be subjected to corona treatment, plasma treatment, flame treatment, or the like on at least the surface on which the polyvinyl alcohol resin film is bonded in order to improve adhesion with the polyvinyl alcohol resin film. . Moreover, in order to improve adhesiveness, you may form thin layers, such as a primer layer, in the surface at the side by which the polyvinyl alcohol-type resin film of a base film is formed.
(Primer layer)
A primer layer may be formed on the surface of the base film on which the polyvinyl alcohol resin film is bonded. The primer layer is not particularly limited as long as it is a material that exhibits a certain degree of strong adhesion to both the base film and the polyvinyl alcohol-based resin film. For example, a thermoplastic resin excellent in transparency, thermal stability, stretchability, etc. is used. Specific examples include acrylic resins and polyvinyl alcohol resins, but are not limited thereto. Among these, a polyvinyl alcohol resin having good adhesion is preferably used.
  As a polyvinyl alcohol-type resin used as a primer layer, polyvinyl alcohol resin and its derivative (s) are mentioned, for example. Derivatives of polyvinyl alcohol resin include polyvinyl formal, polyvinyl acetal, etc., olefins such as ethylene and propylene, unsaturated carboxylic acids such as acrylic acid, methacrylic acid and crotonic acid, and alkyl esters of unsaturated carboxylic acids. And those modified with acrylamide or the like. Among the above-mentioned polyvinyl alcohol-based resin materials, it is preferable to use a polyvinyl alcohol resin.
  In order to increase the strength of the primer layer, a crosslinking agent may be added to the thermoplastic resin. As the cross-linking agent to be added to the thermoplastic resin, known ones such as organic and inorganic can be used. What is necessary is just to select a more suitable thing suitably with respect to the thermoplastic resin to be used. For example, in addition to low molecular crosslinkers such as epoxy crosslinkers, isocyanate crosslinkers, dialdehyde crosslinkers, metal chelate crosslinkers, high molecular weight polymers such as methylolated melamine resins and polyamide epoxy resins. A crosslinking agent or the like can also be used. When a polyvinyl alcohol resin is used as the thermoplastic resin, it is particularly preferable to use a polyamide epoxy resin, a methylolated melamine, a dialdehyde, a metal chelate crosslinking agent, or the like as the crosslinking agent.
  The thickness of a primer layer becomes like this. Preferably it is 0.05-1 micrometer, More preferably, it is 0.1-0.4 micrometer. If the thickness is less than 0.05 μm, the adhesive force between the base film and the polyvinyl alcohol film is reduced, and if it is greater than 1 μm, the polarizing plate becomes thick.
(Adhesive layer)
The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is usually a composition in which an acrylic resin, a styrene resin, a silicone resin, or the like is used as a base polymer and a crosslinking agent such as an isocyanate compound, an epoxy compound, or an aziridine compound is added thereto. Become. Furthermore, a pressure-sensitive adhesive layer exhibiting light scattering properties can be formed by mixing fine particles in the pressure-sensitive adhesive.
  The thickness of the pressure-sensitive adhesive layer is preferably 1 to 40 μm, but it is preferably applied thinly, and more preferably 3 to 25 μm, as long as the workability and durability characteristics are not impaired. When it is 3 to 25 μm, it has good processability and is also suitable for suppressing the dimensional change of the polarizing film. When the pressure-sensitive adhesive layer is less than 1 μm, the tackiness is lowered, and when it exceeds 40 μm, problems such as the pressure-sensitive adhesive protruding easily occur.
  The method of forming the pressure-sensitive adhesive layer on the base film or the polyvinyl alcohol-based resin film is not particularly limited, and each of the above-mentioned base polymers is included on the base film surface or the polyvinyl alcohol-based resin film surface. After applying the solution containing the components and drying to form an adhesive layer, it may be bonded to a separator or other type of film, or after forming the adhesive layer on the separator, the substrate film surface or polyvinyl You may affix and laminate | stack on the alcohol-type resin film surface. In addition, when forming the pressure-sensitive adhesive layer on the base film or the polyvinyl alcohol-based resin film surface, if necessary, the base film surface or the polyvinyl alcohol-based resin film surface, or one or both of the pressure-sensitive adhesive layer is adhered, For example, corona treatment or the like may be performed.
(Adhesive layer)
Examples of the adhesive constituting the adhesive layer include a water-based adhesive using a polyvinyl alcohol-based resin aqueous solution, a water-based two-component urethane-based emulsion adhesive, and the like. Among these, a polyvinyl alcohol resin aqueous solution is preferably used. Polyvinyl alcohol resins used as adhesives include vinyl alcohol homopolymers obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, as well as other single quantities copolymerizable with vinyl acetate. And vinyl alcohol copolymers obtained by saponifying the copolymer with the polymer, and modified polyvinyl alcohol polymers obtained by partially modifying the hydroxyl groups. A polyhydric aldehyde, a water-soluble epoxy compound, a melamine compound, a zirconia compound, a zinc compound, or the like may be added as an additive to the water-based adhesive. When such a water-based adhesive is used, the adhesive layer obtained therefrom is usually much thinner than 1 μm, and even when the cross section is observed with a normal optical microscope, the adhesive layer is practically not observed.
  The method of laminating the film using the water-based adhesive is not particularly limited, and the adhesive is evenly applied or poured onto the surface of the base film or the polyvinyl alcohol-based resin film, and the other film is applied to the coated surface. The method of laminating | stacking, bonding with a roll etc., and drying is mentioned. Usually, an adhesive agent is apply | coated at the temperature of 15-40 degreeC after the preparation, and the bonding temperature is the range of 15-30 degreeC normally.
  When using a water-system adhesive, after bonding a film, in order to remove the water contained in a water-system adhesive, it is made to dry. The temperature of the drying furnace is preferably 30 ° C to 90 ° C. If it is less than 30 ° C., the adhesive surface tends to be peeled off. If it is 90 ° C. or higher, the optical performance of the polarizer or the like may be deteriorated by heat. The drying time can be 10 to 1000 seconds.
  After drying, it may be further cured at room temperature or slightly higher temperature, for example, at a temperature of about 20 to 45 ° C. for about 12 to 600 hours. The temperature at the time of curing is generally set lower than the temperature adopted at the time of drying.
  Moreover, a photocurable adhesive can also be used as a non-aqueous adhesive. Examples of the photocurable adhesive include a mixture of a photocurable epoxy resin and a photocationic polymerization initiator.
  As a method of laminating a film with a photocurable adhesive, a conventionally known method can be used. For example, casting method, Mayer bar coating method, gravure coating method, comma coater method, doctor plate method, die coating method Examples of the method include applying an adhesive to the adhesive surface of the film by a dip coating method, a spraying method, and the like, and superimposing two films. The casting method is a method in which two films as an object to be coated are moved in a substantially vertical direction, generally in a horizontal direction, or in an oblique direction between the two, and an adhesive is allowed to flow down and spread on the surface. is there.
  After the adhesive is applied to the surface of the film, it is bonded by sandwiching the film with a nip roll or the like. Moreover, the method of pressing this laminated body with a roll etc. and spreading it uniformly can also be used suitably. In this case, a metal, rubber, or the like can be used as the material of the roll. Furthermore, a method in which this laminate is passed between rolls and pressed to spread is preferably employed. In this case, these rolls may be made of the same material or different materials. The thickness of the adhesive layer after being bonded using the nip roll or the like before drying or curing is preferably 5 μm or less and 0.01 μm or more.
  In order to improve adhesiveness, surface treatment such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame (flame) treatment, and saponification treatment may be appropriately performed on the adhesion surface of the film. Examples of the saponification treatment include a method of immersing in an aqueous alkali solution such as sodium hydroxide or potassium hydroxide.
  When a photocurable resin is used as an adhesive, the photocurable adhesive is cured by irradiating active energy rays after laminating the films. The light source of the active energy ray is not particularly limited, but an active energy ray having a light emission distribution at a wavelength of 400 nm or less is preferable. Specifically, the low-pressure mercury lamp, the medium-pressure mercury lamp, the high-pressure mercury lamp, the ultrahigh-pressure mercury lamp, the chemical lamp, and the black light lamp A microwave excitation mercury lamp, a metal halide lamp and the like are preferably used.
The light irradiation intensity to the photocurable adhesive is appropriately determined depending on the composition of the photocurable adhesive and is not particularly limited, but the irradiation intensity in the wavelength region effective for activating the polymerization initiator is 0.1 to 6000 mW / it is preferable that the cm 2. When the irradiation intensity is 0.1 mW / cm 2 or more, the reaction time does not become too long, and when it is 6000 mW / cm 2 or less, the epoxy is generated by the heat radiated from the light source and the heat generated when the photo-curable adhesive is cured. There is little risk of yellowing of the resin or deterioration of the polarizing film. The light irradiation time to the photocurable adhesive is not particularly limited and is applied according to the photocurable adhesive to be cured, but the integrated light amount expressed as the product of the irradiation intensity and the irradiation time. Is preferably set to be 10 to 10,000 mJ / cm 2 . When the cumulative amount of light to the photocurable adhesive is 10 mJ / cm 2 or more, a sufficient amount of active species derived from the polymerization initiator can be generated to allow the curing reaction to proceed more reliably, and at 10,000 mJ / cm 2 or less. In some cases, irradiation time does not become too long and good productivity can be maintained. The thickness of the adhesive layer after irradiation with active energy rays is usually about 0.001 to 5 μm, preferably 0.01 μm or more and 2 μm or less, more preferably 0.01 μm or more and 1 μm or less. .
  When curing a photocurable adhesive on a substrate film or polyvinyl alcohol resin film by irradiation with active energy rays, various functions of the polarizing plate after all steps such as transmittance, hue, and transparency of these films It is preferable to perform the curing under the condition that does not decrease.
<Extension process (S20)>
Here, a laminated film composed of a base film and a polyvinyl alcohol-based resin film is uniaxially stretched. Preferably, uniaxial stretching is performed so that the stretching ratio is more than 5 times and not more than 17 times. More preferably, it is uniaxially stretched so that the stretch ratio is more than 5 times and not more than 8 times. If the draw ratio is 5 times or less, the polyvinyl alcohol-based resin film is not sufficiently oriented, and as a result, the degree of polarization of the polarizer layer may not be sufficiently high. On the other hand, when the draw ratio exceeds 17 times, breakage of the laminated film at the time of stretching tends to occur, so that workability and handling properties in a subsequent process may be deteriorated. The stretching process in the stretching step (S20) is not limited to one-stage stretching, and can be performed in multiple stages. In the case of performing in multiple stages, it is preferable to perform the stretching treatment so that the stretching ratio is more than 5 times by combining all the stages of the stretching treatment.
  In the extending process (S20) in this invention, the longitudinal stretch process performed with respect to the longitudinal direction of a laminated | multilayer film, the horizontal stretch process extended | stretched with respect to the width direction, etc. can be implemented. Examples of the longitudinal stretching method include an inter-roll stretching method and a compression stretching method, and examples of the transverse stretching method include a tenter method.
<Dyeing process (S30)>
Here, the resin layer of the laminated film is dyed with a dichroic dye. Examples of the dichroic dye include iodine and organic dyes. Examples of organic dyes include Red BR, Red LR, Red R, Pink LB, Rubin BL, Bordeaux GS, Sky Blue LG, Lemon Yellow, Blue BR, Blue 2R, Navy RY, Green LG, Violet LB, Violet B, Black H, Black B, Black GSP, Yellow 3G, Yellow R, Orange LR, Orange 3R, Scarlet GL, Scarlet KGL, Congo Red, Brilliant Violet BK, Spura Blue G, Spura Blue GL, Spura Orange GL, Direct Sky Blue, Direct First Orange S, First Black, etc. can be used. One kind of these dichroic substances may be used, or two or more kinds may be used in combination.
  The dyeing step is performed, for example, by immersing the entire stretched film in an aqueous solution (dye solution) containing a dichroic dye. As the staining solution, a solution in which the above dichroic dye is dissolved in a solvent can be used. As a solvent for the dyeing solution, water is generally used, but an organic solvent compatible with water may be further added. The concentration of the dichroic dye is preferably 0.01 to 10% by weight, more preferably 0.02 to 7% by weight, and particularly preferably 0.025 to 5% by weight.
  When iodine is used as the dichroic dye, it is preferable to further add an iodide because the dyeing efficiency can be further improved. Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, and iodide. Examples include titanium. The addition ratio of these iodides is preferably 0.01 to 20% by weight in the dyeing solution. Of the iodides, it is preferable to add potassium iodide. When potassium iodide is added, the ratio of iodine to potassium iodide is preferably in the range of 1: 5 to 1: 100, more preferably in the range of 1: 6 to 1:80 by weight. , Particularly preferably in the range of 1: 7 to 1:70.
  The immersion time of the stretched film in the dyeing solution is not particularly limited, but is usually preferably in the range of 15 seconds to 15 minutes, and more preferably 1 minute to 3 minutes. Moreover, it is preferable that it is in the range of 10-60 degreeC, and, as for the temperature of a dyeing | staining solution, it is more preferable that it exists in the range of 20-40 degreeC.
<Crosslinking process>
Subsequent to the dyeing step, a crosslinking treatment can be performed. The crosslinking treatment is performed, for example, by immersing the stretched film in a solution containing a crosslinking agent (crosslinking solution). Conventionally known substances can be used as the crosslinking agent. Examples thereof include boron compounds such as boric acid and borax, glyoxal, and glutaraldehyde. One kind of these may be used, or two or more kinds may be used in combination.
  As the crosslinking solution, a solution in which a crosslinking agent is dissolved in a solvent can be used. As the solvent, for example, water can be used, but an organic solvent compatible with water may be further included. Although the density | concentration of the crosslinking agent in a crosslinking solution is not limited to this, It is preferable to exist in the range of 1-20 weight%, and it is more preferable that it is 6-15 weight%.
  Iodide may be added to the crosslinking solution. By adding iodide, the in-plane polarization characteristics of the resin layer can be made more uniform. Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, and titanium iodide. Is mentioned. The iodide content is 0.05 to 15% by weight, more preferably 0.5 to 8% by weight.
  The immersion time of the laminated film in the crosslinking solution is usually preferably from 15 seconds to 20 minutes, and more preferably from 30 seconds to 15 minutes. Moreover, it is preferable that the temperature of a crosslinking solution exists in the range of 10-80 degreeC.
<Washing process>
It is preferable to perform a washing step after the crosslinking step. As the washing step, a water washing treatment can be performed. The water washing treatment can be usually performed by immersing the laminated film in pure water such as ion exchange water or distilled water. The water washing temperature is usually in the range of 3 to 50 ° C, preferably 4 to 20 ° C. The immersion time is usually 2 to 300 seconds, preferably 3 to 240 seconds.
  In the washing step, washing treatment with an iodide solution and water washing treatment may be combined, and a solution in which liquid alcohol such as methanol, ethanol, isopropyl alcohol, butanol, propanol or the like is appropriately blended may be used.
<Drying process>
After the cleaning process, a drying process may be performed. Any appropriate method (for example, natural drying, ventilation drying, heat drying) can be adopted as the drying step. For example, the drying temperature in the case of heat drying is usually 20 to 95 ° C., and the drying time is usually about 1 to 15 minutes. Through the above steps, the polyvinyl alcohol-based resin film has a function as a polarizer layer, and a polarizing laminated film having a polarizer layer on one surface of the base film is manufactured.
(Polarizer layer)
Specifically, the polarizer layer is obtained by adsorbing and orienting a dichroic dye on a uniaxially stretched polyvinyl alcohol resin film. The draw ratio is preferably more than 5 times, more preferably more than 5 times and not more than 17 times.
  The thickness of the polarizer layer (the thickness of the stretched polyvinyl alcohol resin film) is preferably 25 μm or less, more preferably 20 μm or less, and preferably 2 μm or more. By setting the thickness of the polarizer layer to 25 μm or less, a thin polarizing laminated film can be formed.
<Protective film bonding step (S40)>
A protective film is bonded to the surface opposite to the surface on the base film side of the polarizer layer in the polarizing laminated film. The method for bonding the polarizer layer and the protective film is not particularly limited. For example, a pressure-sensitive adhesive layer or an adhesive layer is formed on the bonding surface of the polarizer layer and / or the protective film, and both are bonded via the pressure-sensitive adhesive layer or the adhesive layer. Materials suitable as the pressure-sensitive adhesive layer and the adhesive layer are the same as the pressure-sensitive adhesive layer and the adhesive layer described in the above-described column of the resin film bonding step (S10).
(Protective film)
The protective film may be a simple protective film having no optical function, or may be a protective film having both optical functions such as a retardation film and a brightness enhancement film.
  The material of the protective film is not particularly limited, but for example, a cyclic polyolefin resin film, a cellulose acetate resin film made of a resin such as triacetyl cellulose or diacetyl cellulose, polyethylene terephthalate, polyethylene naphthalate, poly Examples of the film that have been widely used in the art include polyester-based resin films made of a resin such as butylene terephthalate, polycarbonate-based resin films, acrylic-based resin films, and polypropylene-based resin films.
  Examples of the cyclic polyolefin-based resin include appropriate commercial products such as Topas (registered trademark) (manufactured by Ticona), Arton (registered trademark) (manufactured by JSR Corporation), ZEONOR (registered trademark) (Nippon ZEON ( ZEONEX (registered trademark) (manufactured by Nippon Zeon Co., Ltd.), Apel (registered trademark) (manufactured by Mitsui Chemicals, Inc.) can be suitably used. When such a cyclic polyolefin resin is formed into a film, a known method such as a solvent casting method or a melt extrusion method is appropriately used. In addition, pre-filmed cyclic polyolefins such as Essina (registered trademark) (manufactured by Sekisui Chemical Co., Ltd.), SCA40 (manufactured by Sekisui Chemical Co., Ltd.), Zeonoa (registered trademark) film (manufactured by Optes Co., Ltd.), etc. A commercial product of a film made of a resin may be used.
  The cyclic polyolefin resin film may be uniaxially stretched or biaxially stretched. An arbitrary retardation value can be imparted to the cyclic polyolefin-based resin film by stretching. Stretching is usually performed continuously while unwinding the film roll, and is stretched in the heating furnace in the roll traveling direction, the direction perpendicular to the traveling direction, or both. The temperature of the heating furnace is usually in the range from the vicinity of the glass transition temperature of the cyclic polyolefin resin to the glass transition temperature + 100 ° C. The draw ratio is usually 1.1 to 6 times, preferably 1.1 to 3.5 times in one direction.
  Since the cyclic polyolefin resin film generally has poor surface activity, the surface to be bonded to the polarizer layer is subjected to surface treatment such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame (flame) treatment, and saponification treatment. Is preferred. Among these, plasma treatment and corona treatment that can be performed relatively easily are preferable.
  Examples of the cellulose acetate-based resin film include commercially available products such as Fujitac (registered trademark) TD80 (manufactured by Fuji Film Co., Ltd.), Fujitac (registered trademark) TD80UF (manufactured by Fuji Film Co., Ltd.), and Fujitac (registered trademark). TD80UZ (Fuji Film Co., Ltd.), Fujitac (registered trademark) TD40UZ (Fuji Film Co., Ltd.), KC8UX2M (Konica Minolta Opto Co., Ltd.), KC4UY (Konica Minolta Opto Co., Ltd.) are preferably used. be able to.
  A liquid crystal layer or the like may be formed on the surface of the cellulose acetate-based resin film in order to improve viewing angle characteristics. Moreover, in order to provide a phase difference, what stretched the cellulose acetate type-resin film may be used. The cellulose acetate-based resin film is usually subjected to a saponification treatment in order to improve the adhesiveness with the polarizing film. As the saponification treatment, a method of immersing in an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide can be employed.
  Optical layers such as a hard coat layer, an antiglare layer, and an antireflection layer can be formed on the surface of the protective film as described above. The method for forming these optical layers on the surface of the protective film is not particularly limited, and a known method can be used.
  The thickness of the protective film is preferably as thin as possible from the demand for thinning, is preferably 90 μm or less, and more preferably 50 μm or less. On the other hand, if it is too thin, the strength is lowered and the processability is poor, and therefore it is preferably 5 μm or more.
<Base film peeling step (S50)>
In the manufacturing method of the polarizing plate of this embodiment, as shown in FIG. 2, a base film peeling process (S50) is performed after the protective film bonding process (S40) which bonds a protective film to a polarizer layer. In the base film peeling step (S50), the base film is peeled from the polarizing laminated film. The peeling method of a base film is not specifically limited, The method similar to the peeling process of the peeling film performed with a normal polarizing plate with an adhesive can be employ | adopted. After the protective film laminating step (S40), it may be peeled off as it is, or after being wound up once in a roll shape, a separate peeling step may be provided and peeled off. Through the above steps, a polarizing plate having a protective film on one surface of the polarizer layer is produced.
(Other optical layers)
In practical use, the polarizing plate can be used as a polarizing plate in which other optical layers are laminated. Moreover, the said protective film may have a function of these optical layers.
  Examples of other optical layers include a reflective polarizing film that transmits certain types of polarized light and reflects polarized light that exhibits the opposite properties, a film with an antiglare function having an uneven shape on the surface, and a surface antireflection function. Examples thereof include an attached film, 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.
  Commercially available products corresponding to reflective polarizing films that transmit certain types of polarized light and reflect polarized light that exhibits the opposite properties include DBEF (available from 3M, Sumitomo 3M Co., Ltd.), APF (Available from 3M, available from Sumitomo 3M Limited). Examples of the viewing angle compensation film include an optical compensation film coated with a liquid crystal compound on the surface of the substrate and oriented, a retardation film made of a polycarbonate resin, and a retardation film made of a cyclic polyolefin resin. Commercially available products corresponding to an optical compensation film coated with a liquid crystal compound on the substrate surface and oriented are WV film (Fuji Film Co., Ltd.), NH film (Shin Nippon Oil Co., Ltd.), NR Examples include films (manufactured by Nippon Oil Corporation). Commercial products corresponding to retardation films made of cyclic polyolefin resins include Arton (registered trademark) film (manufactured by JSR Corporation), Essina (registered trademark) (manufactured by Sekisui Chemical Co., Ltd.), Zeonor ( Registered trademark) film (manufactured by Optes Co., Ltd.).
[Example 1]
<Production of polyvinyl alcohol-based resin film>
A powder of a fully saponified polyvinyl alcohol resin (trade name: PVA124) sold by Kuraray Co., Ltd. was dissolved in 90 ° C. warm water to prepare a polyvinyl alcohol resin aqueous solution having a solid content concentration of 10 wt%. The obtained aqueous polyvinyl alcohol resin solution was applied to a PET substrate having been subjected to a release treatment with a thickness of about 400 μm by a lip coating method. After drying at 50 ° C. for 10 minutes, the polyvinyl alcohol resin film was peeled off from the PET substrate and further dried at 80 ° C. for 5 minutes to obtain a curl-free polyvinyl alcohol resin film. The thickness after drying was 41 μm.
<Resin film bonding process>
A polyvinyl alcohol powder and a crosslinking agent were dissolved in hot water to prepare an aqueous adhesive solution having the following composition. A 110 μm-thick base film made of polypropylene resin (trade name: FLX80E4, manufactured by Sumitomo Chemical Co., Ltd.) is subjected to corona discharge treatment, and the above-mentioned adhesive aqueous solution has a thickness of 0 after drying using a gravure coater. It was applied so as to be about 2 μm. Then, after bonding together the above-mentioned polyvinyl alcohol-type resin film, it was made to dry at 50 degreeC for 3 minutes, and the laminated | multilayer film was obtained. The obtained laminated film was flat and easy to handle.
(Adhesive aqueous solution)
Water: 100 parts by weight, polyvinyl alcohol resin powder (manufactured by Kuraray Co., Ltd., average polymerization degree 18000, trade name: KL-318): 3 parts by weight, polyamide epoxy resin (crosslinking agent, manufactured by Sumika Chemtex Co., Ltd., product) Name: SR650 (30)): 1.5 parts by weight.
<Extension process>
The laminated film was subjected to 5.8 times free end uniaxial stretching at 160 ° C. using a tenter apparatus. The thickness of the stretched polyvinyl alcohol resin film was 18 μm.
<Dyeing process>
Then, after immersing the laminated film in a dyeing solution at 30 ° C., which is a mixed aqueous solution of iodine and potassium iodide, for about 180 seconds to dye the polyvinyl alcohol-based resin film, the excess iodine solution was washed away with 10 ° C. pure water. . Next, it was immersed in a crosslinking solution, which is a mixed aqueous solution of boric acid and potassium iodide at 76 ° C. for 300 seconds. Thereafter, it was washed with pure water at 10 ° C. for 4 seconds, and finally, excess water on the surface was removed with a nip roll. The mixing ratio of the chemical solution in each layer is as follows. The laminated film after dyeing was dried at 80 ° C. for 5 minutes to obtain a polarizing laminated film.
(Dyeing solution)
Water: 100 parts by weight, iodine: 0.6 parts by weight, potassium iodide: 10 parts by weight.
(Crosslinking solution)
Water: 100 parts by weight, boric acid: 9.5 parts by weight, potassium iodide: 5 parts by weight.
<Protective film bonding process>
An aqueous adhesive solution similar to that in the resin film bonding step was prepared. The protective film (TAC: KC4UY manufactured by Konica Minolta Opto Co., Ltd.) is bonded after applying the above-mentioned adhesive aqueous solution to the surface opposite to the surface on the base film side of the polarizer layer of the polarizing laminate film. And the polarizing plate which consists of five layers of a base film, an adhesive bond layer, a polarizer layer, an adhesive bond layer, and a protective film was obtained.
<Base film peeling process>
The upper polarizing plate was dried at 80 ° C. for 5 minutes to obtain a polarizing plate. The base film was peeled from the obtained polarizing plate. The base film was easily peeled off to obtain a polarizing plate comprising 4 layers of an adhesive layer, a polarizer layer, an adhesive layer and a protective film. The thickness of the polarizer layer was 18 μm. The polarizing performance of the obtained polarizing plate was measured with a spectrophotometer (V7100) manufactured by JASCO Corporation. The incident direction of light was from the polarizer layer side. The transmittance correction single transmittance was 41.8%, and the visibility correction polarization degree was 99.997%, which was very excellent in polarization performance, and was sufficiently usable as a polarizing plate.
[Comparative Example 1]
After performing the corona discharge treatment on the same base film as in Example 1, the aqueous polyvinyl alcohol resin solution used in the production of the polyvinyl alcohol-based resin film in Example 1 was directly applied by the gap coating method. Subsequently, drying was carried out continuously at 50 ° C. for 10 minutes and at 80 ° C. for 5 minutes. However, significant shrinkage occurred due to drying shrinkage of the polyvinyl alcohol resin layer, and folding of the edge at the outlet of the drying furnace occurred. did. The obtained polyvinyl alcohol resin layer had a thickness after drying of about 39 μm.

Claims (5)

  1. A method for producing a polarizing laminated film comprising a base film and a polarizer layer formed on one surface of the base film,
    A resin film laminating step of laminating a resin film made of a polyvinyl alcohol resin having a thickness of 15 to 45 μm on one surface of the base film to obtain a laminated film;
    A stretching step of uniaxially stretching the laminated film;
    The manufacturing method of a polarizing laminated film including the dyeing process of dyeing the resin film of a monoaxially stretched laminated film with iodine or an organic dye to form a polarizer layer in this order.
  2.   The manufacturing method of the light-polarizing laminated film of Claim 1 which manufactures a light-polarizing laminated film provided with the said base film and the polarizer layer formed in one surface of the said base film continuously.
  3.   The manufacturing method of the polarizing laminated film of Claim 1 or 2 which bonds the said resin film to one surface of the said base film through an adhesive layer or an adhesive bond layer in the said resin film bonding process. .
  4. The resin film used in the resin film bonding step is
    A resin layer forming step of forming a resin layer comprising a polyvinyl alcohol resin on a support;
    A first drying step of drying the resin layer formed on the support;
    A resin layer separation step of separating the dried resin layer from the support to obtain the resin layer;
    A second drying step of drying the peeled resin layer at a high drying temperature than in the first Drying step, a resin film produced by the method comprising in this order,
    The manufacturing method of the light-polarizing laminated film of any one of Claims 1-3 .
  5. A method for producing a polarizing plate comprising a polarizer layer and a protective film formed on one surface of the polarizer layer,
    After manufacturing a polarizing laminated film with the manufacturing method of any one of Claims 1-4 ,
    A protective film laminating step of laminating a protective film on a surface opposite to the surface on the base film side of the polarizer layer in the polarizing laminated film;
    The manufacturing method of a polarizing plate including the base film peeling process which peels the said base film from the said polarizing laminated film in this order.
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Families Citing this family (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101498822B1 (en) 2012-11-16 2015-03-05 주식회사 엘지화학 Preparing method for thin polarizer, thin polarizer and polarizing plate comprising the same
KR101498823B1 (en) * 2012-11-16 2015-03-05 주식회사 엘지화학 Preparing method for thin polarizer, thin polarizer and polarizing plate comprising the same
WO2014084154A1 (en) * 2012-11-30 2014-06-05 株式会社クラレ Multilayer film
JP2014232126A (en) * 2013-03-19 2014-12-11 日東電工株式会社 Method for manufacturing polarizing plate
CN104395791B (en) * 2013-06-18 2018-03-13 Lg化学株式会社 Thin Polarizer and its manufacture method
KR101555782B1 (en) 2013-06-18 2015-09-24 주식회사 엘지화학 Thin polarizing plate and method for maunfacturing the same
KR101460477B1 (en) 2013-06-18 2014-11-10 주식회사 엘지화학 Oriented laminate, preparing method for thin polarizer, thin polarizer manufactured by using the same and polarizing plate comprising the same
KR101460478B1 (en) 2013-06-18 2014-11-10 주식회사 엘지화학 Oriented laminate, preparing method for thin polarizer, thin polarizer manufactured by using the same and polarizing plate comprising the same
KR101460479B1 (en) * 2013-06-18 2014-11-10 주식회사 엘지화학 Oriented laminate, preparing method for thin polarizer, thin polarizer manufactured by using the same and polarizing plate comprising the same
WO2014204147A1 (en) * 2013-06-18 2014-12-24 주식회사 엘지화학 Stretched laminated body, method for manufacturing thin polarizer, thin polarizer manufactured thereby and polarizing plate containing same
KR101705944B1 (en) * 2013-06-19 2017-02-10 주식회사 엘지화학 Laminate
WO2015099267A1 (en) * 2013-12-27 2015-07-02 주식회사 엘지화학 Thin polarizer with excellent optical properties, manufacturing method therefor and polarizing plate including same
KR101620189B1 (en) 2013-12-27 2016-05-12 주식회사 엘지화학 Thin polarizer having a good optical properties, method for manufacturing thereof and polarizing plate comprising the same
JP6249820B2 (en) * 2014-02-27 2017-12-20 住友化学株式会社 Manufacturing method of polarizing plate and polarizing plate
JP6203143B2 (en) * 2014-07-22 2017-09-27 住友化学株式会社 Manufacturing method of polarizing plate
KR101724799B1 (en) 2014-09-15 2017-04-07 주식회사 엘지화학 Preparing method for thin polarizing plate and polarizing plate using the same
JP6138755B2 (en) * 2014-12-24 2017-05-31 日東電工株式会社 Polarizer
JP6563201B2 (en) * 2015-01-14 2019-08-21 日東電工株式会社 Manufacturing method of polarizing film
CN105223639B (en) * 2015-11-16 2019-06-25 云南云天化股份有限公司 The preparation method of slim Pva Polarizing Film
JP2018106137A (en) * 2016-12-28 2018-07-05 日東電工株式会社 Polarizing film with surface protection film and optical member with surface protection film
JP6714522B2 (en) 2017-01-24 2020-06-24 富士フイルム株式会社 Wavelength conversion film
JP2018180407A (en) * 2017-04-19 2018-11-15 住友化学株式会社 Polarizing plate and liquid crystal panel

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2543748B2 (en) * 1987-07-03 1996-10-16 株式会社クラレ Polarizing film and manufacturing method thereof
JP3342517B2 (en) * 1992-10-27 2002-11-11 株式会社クラレ Method for producing PVA-based film and optical film
JP3251073B2 (en) * 1992-10-27 2002-01-28 株式会社クラレ Film and polarizing film
JP4279944B2 (en) * 1999-06-01 2009-06-17 株式会社サンリッツ Manufacturing method of polarizing plate
JP2001191462A (en) * 1999-11-05 2001-07-17 Tohcello Co Ltd Laminate
JP4421737B2 (en) * 2000-05-10 2010-02-24 株式会社カネカ Optical film made of low-birefringence graft-modified norbornene resin
JP2001343522A (en) * 2000-05-31 2001-12-14 Sumitomo Chem Co Ltd Polarizer film and its manufacturing method
JP2001343521A (en) * 2000-05-31 2001-12-14 Sumitomo Chem Co Ltd Polarizing plate and method for manufacturing the same
US6859241B2 (en) * 2001-10-16 2005-02-22