TWI682199B - Method for manufacturing polarizing plate - Google Patents

Abstract

The present invention provides a method for manufacturing a polarizing plate having an excellent appearance. The manufacturing method of the polarizing plate of the present invention includes the steps of obtaining a laminate of a long resin substrate and a polyvinyl alcohol-based resin layer formed on one side of the resin substrate; the step of stretching the laminate; and the polyethylene The step of dyeing the alcohol-based resin layer; the step of trimming the widthwise end of the laminate before dyeing; and, after stretching and dyeing, attaching a long protective film to the polyvinyl alcohol-based resin layer A step of. The end surface of the laminate in the longitudinal direction at the time of lamination is a cut surface formed by cutting edges.

Description

Method for manufacturing polarizing plate

The invention relates to a method for manufacturing polarizing plates.

Background technique

In a liquid crystal display device as a representative image display device, polarizing films are arranged on both sides of the liquid crystal cell due to its image forming method. As a method of manufacturing a polarizing film, for example, a method is proposed in which a laminate having a resin base material and a polyvinyl alcohol (PVA)-based resin layer is stretched and subjected to dyeing treatment to obtain a polarizing film on the resin base material ( For example, Patent Document 1). According to this method, a thin polarizing film can be obtained, which can contribute to the thinning of the image display device in recent years, and thus attracts attention.

The above-mentioned polarizing film is usually attached to a protective film and used as a polarizing plate. When a polarizing film (laminate) formed on the resin substrate is bonded to a protective film, there is a problem that the end portion is easily bent or wrinkled. Therefore, it is proposed to remove the end of the laminate before bonding the protective film (Patent Document 2). However, according to this method, there is a problem that the obtained polarizing plate has a poor appearance.

Advanced technical literature Patent Literature

Patent Literature 1 Japanese Patent Laid-Open No. 2000-338329

Patent Document 2 Japanese Patent No. 5124704 Specification

Summary of the invention

The present invention is made to solve the above-mentioned problems, and its object is to provide a method for manufacturing a polarizing plate having an excellent appearance.

The manufacturing method of the polarizing plate of the present invention includes the steps of obtaining a laminate of a long resin substrate and a polyvinyl alcohol-based resin layer formed on one side of the resin substrate; the step of stretching the laminate; The step of dyeing the polyvinyl alcohol-based resin layer; the step of cutting the edge of the width direction of the laminate before the dyeing; and the sticking on the polyvinyl alcohol-based resin layer after the stretching and dyeing In the step of closing the long-shaped protective film, the end surface of the laminate in the longitudinal direction at the time of the bonding is the cut surface formed by the cut edge.

In one embodiment, the aforementioned trimming is performed before the aforementioned stretching.

In one embodiment, the method further includes the step of winding the laminated body into a roll shape, and performing the above-mentioned trimming after the winding.

In one embodiment, after the stretching, the step of winding the laminated body into a roll shape is further included, and the cutting is performed after the winding.

In one embodiment, the stretching is longitudinal uniaxial stretching.

In one embodiment, the stretching is aerial stretching.

According to other aspects of the present invention, a polarizing plate is provided. This polarizing plate is obtained by the above-mentioned manufacturing method.

According to the present invention, by trimming before dyeing, the In the film bonding step, it is possible to effectively prevent foreign materials from being mixed between the PVA-based resin layer and the protective film. Specifically, by dyeing, the PVA-based resin layer becomes brittle due to cross-linking (for example, due to iodine). When trimming is performed in this state, trimming chips are likely to form, and the trimming chips will become foreign objects when they are bonded. Therefore, by trimming before dyeing, it is possible to effectively prevent the mixing of foreign substances and the generation of air bubbles accompanying the mixing of foreign substances. As a result, a polarizing plate excellent in appearance can be obtained.

10‧‧‧Layered body

10a‧‧‧Cutting piece, width end

11‧‧‧Resin base material

12‧‧‧Polyvinyl alcohol resin layer (polarizing film)

20‧‧‧ lengthwise

FIG. 1 is a partial cross-sectional view of a laminate according to an embodiment of the present invention.

FIG. 2 is an external perspective view showing an example of the trimming step of the present invention.

Ways to implement the invention

Hereinafter, one embodiment of the present invention will be described, but the present invention is not limited to these embodiments.

The method for manufacturing a polarizing plate of the present invention includes the steps of obtaining a laminate of a long resin substrate and a PVA-based resin layer formed on one side of the resin substrate (lamination step); and the step of stretching the laminate ( Stretching step); step of dyeing the PVA-based resin layer (dyeing step); step of trimming the width-direction end of the laminate (trimming step); and laminating a long strip on the PVA-based resin layer The step of protecting the film (laminating step). Hereinafter, each step will be described.

A. Stacking steps

FIG. 1 is a partial cross-sectional view of a laminate according to a preferred embodiment of the present invention. The laminate 10 has a resin base 11 and a polyvinyl alcohol-based resin layer 12. The laminate 10 is produced by stacking a polyvinyl alcohol-based resin layer 12 on a long resin base 11. As a method of forming the polyvinyl alcohol-based resin layer 12, any appropriate method can be adopted. In one embodiment In the formula, a coating liquid containing a polyvinyl alcohol-based resin (hereinafter referred to as “PVA-based resin”) is applied over the entire surface of the resin substrate 11 and dried to form the PVA-based resin layer 12.

As a material for forming the above-mentioned resin base material, any appropriate material can be used. For example, ester resins such as polyethylene terephthalate resins, olefin resins such as cycloolefin resins and polypropylene, (meth)acrylic resins, polyamide resins, and polycarbonate resins can be cited. Resin, its copolymer resin.

The glass transition temperature (Tg) of the resin substrate is preferably 120°C or lower, more preferably 100°C or lower. This is because, when the laminate is stretched, the crystal of the PVA-based resin layer can be suppressed, and the stretchability can be sufficiently ensured. As a result, a polarizing film having excellent optical characteristics (for example, polarization degree) can be manufactured. On the other hand, the glass transition temperature of the resin substrate is preferably 60° C. or higher. In addition, the glass transition temperature (Tg) is a value determined according to JIS K 7121.

The thickness of the resin substrate is preferably 20 μm to 300 μm, more preferably 50 μm to 200 μm. The surface of the resin substrate may be subjected to surface modification treatment (for example, corona treatment, etc.), or an easy adhesion layer may be formed. According to this treatment, a laminate having excellent adhesion between the resin base material and the PVA-based resin layer can be obtained.

As the PVA-based resin forming the PVA-based resin layer, any appropriate resin may be used. For example, polyvinyl alcohol and ethylene-vinyl alcohol copolymer can be mentioned. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. The ethylene-vinyl alcohol copolymer is obtained by saponifying the ethylene-vinyl acetate copolymer. The saponification degree of the PVA-based resin is usually 85 mol% to 100 mol%, preferably 95.0 mol% to 99.95 mol%, and more preferably 99.0 mol% to 99.93 mol%. The degree of saponification can be determined in accordance with JIS K 6726-1994. By using a PVA-based resin having such a degree of saponification, a polarizing film excellent in durability can be obtained. If the degree of saponification is too high, there is a risk of gelation.

The average degree of polymerization of the PVA-based resin can be appropriately selected according to the purpose. The average polymerization degree is usually 1000 to 10000, preferably 1200 to 4500, and more preferably 1500 to 4300. It should be noted that the average degree of polymerization can be obtained in accordance with JIS K 6726-1994.

As the coating liquid, a solution obtained by dissolving the PVA-based resin in a solvent is typically used. Examples of the solvent include polyhydric alcohols such as water, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, various diols, and trimethylolpropane. Amines such as ethylenediamine and diethylenetriamine. These can be used alone or in combination of two or more. Among these, water is preferable. The PVA-based resin concentration of the solution can be set to any appropriate value. For example, it is set according to the degree of polymerization and saponification of the PVA-based resin. The concentration of the PVA-based resin in the solution is, for example, 3 to 20 parts by weight relative to 100 parts by weight of the solvent.

The coating liquid may contain additives. Examples of additives include plasticizers and surfactants. Examples of the plasticizer include polyhydric alcohols such as ethylene glycol and glycerin. Examples of surfactants include nonionic surfactants. These can be used to further improve the uniformity, dyeability, and stretchability of the obtained PVA-based resin layer. In addition, as an additive, for example, an easily-adhesive component may be mentioned. By using an easily adhesive component, the adhesion between the resin substrate and the PVA-based resin layer can be improved. As a result, for example, defects such as peeling of the PVA-based resin layer from the resin base material can be suppressed, and dyeing and water stretching described below can be performed satisfactorily. As an easily-adhesive component, for example, modified PVA such as acetylacetyl-modified PVA can be used.

As a coating method of the coating liquid, any appropriate method can be adopted. For example, a bar coating method, a spin coating method, a wire bar coating method, a dip coating method, a die coating method, a curtain coating method, a spray coating method, a blade coating method (comma coating method, etc.), etc. are mentioned. Coating liquid The coating/drying temperature is, for example, 20°C or higher, preferably 50°C or higher.

The thickness of the PVA-based resin layer is preferably 3 μm to 40 μm, and more preferably 3 μm to 20 μm. The width of the laminate can be set to any appropriate value. Typically, it is 1500 mm or more, preferably 2000 mm to 5000 mm.

B. Stretching step

As a method for stretching the laminate, any appropriate method can be adopted. Specifically, it may be fixed-end stretching (for example, a method using a tenter stretching machine), or may be free-end stretching (for example, a layered body is uniaxially stretched between rolls having different peripheral speeds) method). In addition, it may be simultaneous biaxial stretching (for example, a method using a simultaneous biaxial stretching machine) or successive biaxial stretching. The stretching of the laminate can be performed in one stage or in multiple stages. When carried out in multiple stages, the stretching magnification of the laminate to be described later is the product of the stretching magnifications of each stage.

As the stretching direction of the laminate, any appropriate direction can be selected. In one embodiment, stretching is carried out along the longitudinal direction of the elongated laminate. Specifically, the laminate is transported in the longitudinal direction, which is the transport direction (MD). In other embodiments, stretching is performed in the width direction of the elongated laminate. Specifically, the laminate is transported in the longitudinal direction to a direction (TD) orthogonal to the transport direction (MD).

The stretching method is not particularly limited, and for example, it may be an in-air stretching method or an underwater stretching method while immersing the laminate in a stretching bath.

The stretching temperature of the laminate can be set to any appropriate value according to the material of the resin substrate, the stretching method, and the like. When using the air stretching method, the stretching temperature is preferably above the glass transition temperature (Tg) of the resin substrate, more preferably the resin substrate The glass transition temperature (Tg) + 10 ℃ or more, particularly preferably Tg + 15 ℃ or more. On the other hand, the stretching temperature of the laminate is preferably 170° C. or lower. By stretching at such a temperature, it is possible to suppress the rapid advancement of the crystal of the PVA-based resin, and to suppress defects caused by the crystal (for example, to hinder the orientation of the PVA-based resin layer caused by stretching).

When the underwater stretching method is adopted as the stretching method, the liquid temperature of the stretching bath is preferably 40°C to 85°C, more preferably 50°C to 85°C. With such a temperature, it is possible to perform stretching at a high rate while suppressing the dissolution of the PVA-based resin layer. Specifically, as described above, the glass transition temperature (Tg) of the resin base material is preferably 60° C. or higher from the relationship with the formation of the PVA-based resin layer. At this time, when the stretching temperature is lower than 40°C, the plasticization of the resin base material by water may be taken into consideration, and there is a possibility that the stretching cannot be performed well. On the other hand, the higher the temperature of the stretching bath, the higher the solubility of the PVA-based resin layer, and there is a possibility that excellent optical characteristics may not be obtained. The immersion time of the laminate in the stretching bath is preferably 15 seconds to 5 minutes.

When the underwater stretching method is used, it is preferable to immerse the laminate in a boric acid aqueous solution and perform stretching (boric acid underwater stretching). By using a boric acid aqueous solution as a stretching bath, the PVA-based resin layer can be given rigidity that can withstand tension applied during stretching and water resistance that does not dissolve in water. The boric acid aqueous solution is preferably obtained by dissolving boric acid and/or borate in water as a solvent. The boric acid concentration is preferably 1 part by weight to 10 parts by weight relative to 100 parts by weight of water. By setting the boric acid concentration to 1 part by weight or more, the dissolution of the PVA-based resin layer can be effectively suppressed, and a polarizing film with higher characteristics can be produced. In addition to boric acid or borate, an aqueous solution obtained by dissolving a boron compound such as borax, glyoxal, glutaraldehyde or the like in a solvent can also be used.

The stretching ratio of the laminate is preferably 1.5 times to 3.5 times, and more preferably 2 times to 3 times the original length of the laminate.

The above-mentioned aerial drawing is preferably performed before dyeing described later.

C. Dyeing steps

The above dyeing is typically performed by dyeing the PVA-based resin layer with a dichroic substance. It is preferably performed by adsorbing the dichroic substance to the PVA-based resin layer. Examples of the adsorption method include: a method of immersing a PVA-based resin layer (laminate) in a dyeing liquid containing a dichroic substance; a method of coating the dyeing liquid on the PVA-based resin layer; and spraying the dyeing liquid Method for PVA-based resin layer, etc. The method of immersing the PVA-based resin layer in the dyeing liquid is preferred. This is because the dichroic substance can be adsorbed well.

Examples of the dichroic substance include iodine and organic dyes. These can be used alone or in combination of two or more. The dichroic substance is preferably iodine. When iodine is used as the dichroic substance, the dyeing solution is preferably an aqueous iodine solution. The compounding amount of iodine is preferably 0.1 part by weight to 0.5 part by weight with respect to 100 parts by weight of water. In order to improve the solubility of iodine in water, it is preferable to mix iodide in an iodine aqueous solution. 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. . Among these, potassium iodide is preferable. The compounding amount of the iodide is preferably 0.02 to 20 parts by weight, more preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of water.

In order to suppress the dissolution of the PVA-based resin, the temperature of the dyeing liquid during dyeing is preferably 20°C to 50°C. When the PVA-based resin layer is immersed in the dyeing solution, in order to ensure the transmittance of the PVA-based resin layer, the immersion time is preferably 5 seconds to 5 minutes. In addition, the dyeing conditions (concentration, liquid temperature, immersion time) can be set so that the polarization degree or the monomer transmittance of the polarizing film finally obtained is within a predetermined range. In one embodiment, when the immersion is set so that the polarization degree of the obtained polarizing film is 99.98% or more between. In other embodiments, the immersion time is set so that the monomer transmittance of the obtained polarizing film is 40% to 44%.

D. Trimming steps

Fig. 2 is an external perspective view showing an example of a trimming step. As shown in FIG. 2, before the above dyeing, the width-direction ends 10 a and 10 a of the laminate 10 are trimmed along the longitudinal direction 20 of the laminate 10. The trimming sheet 10a obtained by trimming includes the resin base material and the PVA-based resin layer. The trimming width (width of the trimming piece) is typically 10 mm to 1000 mm. In one embodiment, the width of the trimming edge is set so that the width of the laminate at the time of bonding described later corresponds to the width of the protective film described later. By matching the widths of the two in this way, wrinkles at the ends in the width direction can be eliminated, and the laminate and the protective film can be stably bonded.

By trimming before dyeing, it is possible to more effectively prevent foreign matter from being mixed between the PVA-based resin layer and the protective film in the bonding step with the protective film described later. Specifically, the PVA-based resin layer is cross-linked by dyeing (for example, due to iodine) and becomes brittle. When trimming is performed in this state, trimming chips are likely to occur, and the trimming chips will become foreign objects when they are bonded. Therefore, by trimming before dyeing, it is possible to more effectively prevent the mixing of foreign substances and the generation of air bubbles accompanying the mixing of foreign substances. As a result, a polarizing plate excellent in appearance can be obtained.

It is preferable to perform the trimming before the stretching. By trimming before stretching, it is possible to more effectively prevent foreign materials from being mixed between the PVA-based resin layer and the protective film in the bonding step with the protective film described later. Specifically, when trimming is performed in a state where the orientation of the PVA-based resin layer is increased due to stretching, burrs are likely to occur at the trimming end, and the burrs may become a foreign substance during bonding. In addition, the PVA-based resin layer in a state with high orientation is likely to crack, and it may become difficult to cut edges. Therefore, by pulling Trimming before stretching can achieve good edge trimming, and effectively prevents the mixing of foreign matter and the generation of bubbles accompanying the mixing of foreign matter. As a result, a polarizing plate excellent in appearance can be obtained. Furthermore, the irregularities such as wrinkles, bends, and tightness can be removed, and when embossing is formed on the widthwise end of the laminate in advance, the wrinkles, bends, and tightness can be removed before the embossing or the like is stretched Because of unevenness, it can be stretched stably.

On the basis of the above, by trimming before stretching, a polarizing film having extremely excellent optical characteristics can be obtained. Specifically, when stretching is performed using the difference in circumferential speed between the rollers (longitudinal uniaxial stretching), the edge in the width direction is trimmed before stretching, so that the L/W increases, and the orientation of the polarizing film obtained /Optical characteristics will be significantly improved. In addition, L represents the distance between stretches (distance to which tension is applied by the difference in circumferential speed between rollers), and W represents the width of the laminate.

As a method of trimming the laminate, any appropriate method can be adopted. For example, the elongated laminate may be trimmed while being wound along its longitudinal direction, or may be trimmed without being wound. Examples of trimming (cutting) means include cutting blades such as circular blades and disk blades, and lasers. It should be noted that it is preferable to remove the trimmed pieces by winding or suction.

E. Other

In addition to the above, the above-mentioned layered body may be suitably subjected to a process for forming a polarizing film of the PVA-based resin layer. Examples of the treatment for forming the polarizing film include insolubilization treatment, cross-linking treatment, cleaning treatment, and drying treatment. In addition, the number, timing, and order of these processes are not particularly limited.

The above-mentioned insolubilization treatment is typically performed by immersing a PVA-based resin layer in an aqueous solution of boric acid. By performing insolubilization treatment, PVA resin The layer imparts water resistance. The concentration of the boric acid aqueous solution is preferably 1 part by weight to 4 parts by weight with respect to 100 parts by weight of water. The liquid temperature of the insolubilization bath (boric acid aqueous solution) is preferably 20°C to 50°C. Preferably, the insolubilization treatment is performed before the water stretching and the dyeing treatment.

The above-mentioned cross-linking treatment is typically performed by immersing the PVA-based resin layer in a boric acid aqueous solution. By performing the cross-linking treatment, it is possible to impart water resistance to the PVA-based resin layer. The concentration of the boric acid aqueous solution is preferably 1 part by weight to 5 parts by weight with respect to 100 parts by weight of water. In addition, when the cross-linking treatment is performed after the above-mentioned dyeing treatment, it is preferable to further compound iodide. By compounding iodide, elution of iodine adsorbed on the PVA-based resin layer can be suppressed. The compounding amount of the iodide is preferably 1 part by weight to 5 parts by weight with respect to 100 parts by weight of water. Specific examples of iodide are as described above. The liquid temperature of the cross-linking bath (boric acid aqueous solution) is preferably 20°C to 60°C.

The above-mentioned cleaning treatment is typically performed by immersing a PVA-based resin layer in an aqueous potassium iodide solution. The drying temperature of the above-mentioned drying treatment is preferably 30°C to 100°C.

In one embodiment, the laminate is wound into a roll shape to form an original roll, and after the winding, the trimming is performed. The winding tension is typically 300N to 600N. Winding may be performed so that the PVA-based resin layer becomes the inside (core material side), or may be performed so that the PVA-based resin layer becomes the outside. When the laminate is wound up in the manufacturing process of the polarizing film, for example, when the laminate has local unevenness in film thickness, curling or wrinkling occurs. Such problems are likely to occur at the ends in the width direction. Therefore, by performing the above-mentioned trimming after winding, for example, it is possible to stably stretch. In addition, since the trimming is performed after winding, the original roll of the same width can be used regardless of the width of the bonded protective film, which contributes to the improvement of productivity.

In one embodiment, after the stretching, the layering The step of winding the body into a roll shape is to perform the above-mentioned trimming after winding. By performing the above-mentioned trimming after winding, for example, as described above, it is possible to stably stretch. In addition, since the trimming is performed after winding, the original roll of the same width can be used regardless of the width of the bonded protective film, which contributes to the improvement of productivity. In addition, when sufficient stretching is performed by the above-mentioned stretching (for example, the stretching ratio exceeds 5 times), even the portion (adhesion portion) where the laminates are joined to each other by continuous processing of the laminate is immersed in the dyeing When in a groove or the like, the deformation of the adhesion portion can also be suppressed, and the breakage of the joint portion can be suppressed.

F. Fitting steps

After the above dyeing and stretching, a protective film is laminated on the PVA-based resin layer (polarizing film) of the laminate. Specifically, a long protective film is laminated on the PVA-based resin layer so that the longitudinal directions of the two are aligned. In one embodiment, at the time of bonding, the end surface of the laminate in the longitudinal direction is a cut surface formed by the above-mentioned cut edge. Specifically, between the above-mentioned dyeing step and the bonding step, substantially no new trimming process is applied to the laminate.

The width of the protective film can be set to any appropriate value. Typically, it is 500 mm or more and 3000 mm or less, preferably 1000 mm or more and 2500 mm or less.

As the protective film, any appropriate resin film can be used. Examples of the material for forming the protective film include cellulose resins such as triacetyl cellulose (TAC), cycloolefin resins such as norbornene resins, olefin resins such as polyethylene and polypropylene, and polyester resins. (Meth) acrylic resin. In addition, "(meth)acrylic resin" means acrylic resin and/or methacrylic resin.

The thickness of the protective film is typically 10 μm to 100 μm. It should be noted that the protective film may be subjected to various surface treatments. The protective film not only functions as a protective film for the polarizing film, but also functions as a retardation film or the like.

Use any suitable adhesive or adhesive for the bonding of the protective film. In one embodiment, an adhesive is coated on the surface of the polarizing film, and the protective film is attached. As the adhesive, it can be an aqueous adhesive or a solvent adhesive. Aqueous adhesives are preferably used.

As the above-mentioned water-based adhesive, any appropriate water-based adhesive may be used. A water-based adhesive containing PVA-based resin is preferably used. The average degree of polymerization of the PVA-based resin contained in the water-based adhesive is preferably about 100 to 5,000, and more preferably 1,000 to 4,000, from the viewpoint of adhesiveness. The average saponification degree is preferably about 85 mol% to 100 mol% from the viewpoint of adhesiveness, and more preferably 90 mol% to 100 mol%.

The PVA-based resin contained in the water-based adhesive preferably contains an acetyl group. This is because the adhesion between the PVA-based resin layer and the protective film is excellent and the durability is excellent. The acetoacetyl group-containing PVA-based resin can be obtained, for example, by reacting the PVA-based resin with diketene by an arbitrary method. The degree of modification of the acetoacetyl group containing the acetoacetyl PVA resin is typically 0.1 mol% or more, preferably about 0.1 mol% to 40 mol%, and more preferably 1 mol%~ 20 mol%, Tejia is 2 mol%~7 mol%. It should be noted that the degree of modification of the acetylacetonyl group is a value measured by NMR.

The resin concentration of the water-based adhesive is preferably 0.1% by weight to 15% by weight, and more preferably 0.5% by weight to 10% by weight.

The thickness of the adhesive at the time of application can be set to any appropriate value. For example, to obtain an adhesive layer with a desired thickness after heating (drying) Setting. The thickness of the adhesive layer is preferably 10 nm to 300 nm, more preferably 10 nm to 200 nm, and particularly preferably 20 nm to 150 nm.

Preferably, after the protective film is attached to the PVA-based resin layer, heating is performed. The heating temperature is preferably 50°C or higher, more preferably 60°C or higher, and particularly preferably 80°C or higher. It should be noted that the heating performed after bonding the protective film may also serve as the above-mentioned drying treatment.

G. Stripping steps

In one embodiment, the resin substrate is peeled from the PVA-based resin layer (polarizing film). Preferably, before peeling off the resin base material, the width direction end of the polarizing film laminate formed by laminating a protective film on the laminate is trimmed. At the junction of the widthwise end of the laminate and the protective film, joint failure (for example, wrinkles) is likely to occur, and this part is removed by trimming to achieve excellent peelability of the resin substrate. Specifically, it is possible to prevent the above-mentioned defective joint portion from being a starting point to cause a peeling defect (for example, breakage) of the resin base material, and it is possible to peel the resin base material well. As a result, a polarizing plate with a more excellent appearance can be obtained.

H. Polarizer

The polarizing plate of the present invention includes the polarizing film and the protective film disposed on one side of the polarizing film. The polarizing film is substantially a PVA-based resin film obtained by adsorption orientation of a dichroic substance. The thickness of the polarizing film is preferably 10 μm or less, more preferably 7 μm or less, and particularly preferably 5 μm or less. On the other hand, the thickness of the polarizing film is preferably 0.5 μm or more, and more preferably 1.0 μm or more. The polarizing film preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The monomer transmittance of the polarizing film is preferably 40.0% or more, more preferably 41.0% or more, still more preferably 42.0% or more, and particularly preferably 43.0% or more. The polarization degree of the polarizing film is preferably 99.8% or more, and more preferably 99.9% or more. One step is better than 99.95%.

Industrial availability

The polarizing plate of the present invention can be suitably used as a liquid crystal panel of a liquid crystal television, a liquid crystal display, a mobile phone, a digital camera, a video camera, a portable game machine, a car navigation system, a photocopier, a printer, a facsimile machine, a clock, a microwave oven, etc. 3. Anti-reflection film for organic EL devices.

10‧‧‧Layered body

10a‧‧‧Cutting piece, width end

20‧‧‧ lengthwise

Claims (7)

A method for manufacturing a polarizing plate, comprising the steps of: obtaining a laminate of an elongated resin substrate and a polyvinyl alcohol-based resin layer formed on the entire surface of one side of the resin substrate; stretching the laminate; Dyeing the polyvinyl alcohol-based resin layer; before the dyeing, trimming the edges of the laminate in the width direction; and after the stretching and dyeing, bonding the long length on the polyvinyl alcohol-based resin layer In the strip-shaped protective film, the longitudinal end face of the laminate at the time of lamination is a cut surface formed by the cut edge. The manufacturing method according to claim 1, wherein the aforementioned trimming is performed before the aforementioned stretching. The manufacturing method according to claim 1, further comprising the step of winding the laminated body into a roll shape, and performing the aforementioned trimming after the winding. The manufacturing method according to claim 1, wherein after the stretching, the step of winding the laminated body into a roll shape is further included, and the edge trimming is performed after the winding. The manufacturing method according to claim 1, wherein the aforementioned stretching is longitudinal uniaxial stretching. The manufacturing method according to claim 1, wherein the aforementioned stretching is aerial stretching. A polarizing plate obtained by the manufacturing method according to claim 1.

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