KR20160000459A - Method for manufacturing polarizing plate - Google Patents

Abstract

A method for producing a polarizing plate according to the present invention is a method for producing a polarizing plate comprising a polarizing laminated plate in which a polarizing plate protective film is laminated on one surface and a protective film of a pressure sensitive adhesive is laminated on the other surface, To prepare a polarizing plate in which a protective film is laminated on both surfaces. Further, in the method of producing a polarizing plate according to the present invention, it is preferable that, when cutting the polarizing laminate, the upper surface of the adhesive protective film is covered with a covering sheet.

Description

METHOD FOR MANUFACTURING POLARIZING PLATE [0002]

The present invention relates to a method for producing a polarizing plate which is less prone to cracking.

BACKGROUND ART A polarizing plate is widely used as a polarized light supplying element, a polarized light detecting element, and the like in a liquid crystal display. As such a polarizing plate, conventionally, a polarizer protective film made of triacetyl cellulose (TAC) is adhered to a polarizer obtained by adsorbing and orienting a dichroic dye on a polyvinyl alcohol (PVA) film has been used 2010-211213 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2010-276673 (Patent Document 2)].

The production process of the polarizing plate generally comprises a lamination process of each layer and a cutting process.

The lamination step is a step of laminating a polarizer, a polarizer protective film, a pressure-sensitive adhesive, a polarizing plate protective film, a pressure-sensitive adhesive protective film and the like, or a retardation plate as required. Usually, a polarizing plate protective film is laminated on one side and a pressure-sensitive adhesive protective film is laminated on the other side. The cutting step is a step of cutting the laminate obtained in the laminating step to a desired dimension to obtain a polarizing plate in which a protective film is laminated on both surfaces.

Cutting of the laminate in the cutting step is usually performed by cutting the polarizing plate protective film from the surface of the polarizing plate protective film. This is because when the polarizing plate in which protective films are laminated on both surfaces is in the form of a product, it is common that the polarizing plate protective film side becomes the surface and the pressure-sensitive adhesive protective film side becomes the back side. (Surface) of each layer. Usually, the thus obtained polarizing plate is shipped in a state in which a polarizing plate protective film is laminated on one side and a protective film of a pressure-sensitive adhesive is laminated on the other side, and is bonded to the liquid crystal cell in a liquid crystal panel manufacturing factory. When bonding the polarizing plate and the liquid crystal cell, the polarizing plate is adhered to the liquid crystal cell with an adhesive which appears by peeling the adhesive protective film laminated on the polarizing plate. In a liquid crystal panel manufacturing factory, defects are usually observed in a state in which a polarizing plate protective film is laminated on a laminate of a polarizing plate and a liquid crystal cell. For this reason, if there is a defect in the polarizing plate protective film, the entire bonded product may be discarded, and care must be taken so that the polarizing plate protective film is not scratched during production of the polarizing plate. On the other hand, with respect to the pressure-sensitive adhesive protective film which is peeled off when the polarizing plate is attached to the liquid crystal cell, slight scratches are allowed.

In recent years, as the performance of mobile information terminals such as mobile phones, smart phones, and liquid crystal display devices having touch panels has been improved, the polarizing plates used therefor have not been able to be used under more severe conditions Is required.

According to the study of the present inventor, it has been found that when water adheres to the polarizing plate due to condensation or the like, cracks (cracks) are likely to occur. Such an idea is that, for example, when a portable information terminal such as a cellular phone or a smart phone is used to enter a room where the room has been cooled from outside in the summer, or to go out of the room where the room was heated in winter, There is a fear that it will happen when you go.

Thus, the present inventors have studied to produce a polarizing plate in which cracking does not occur even when water adheres due to condensation or the like, thereby completing the present invention.

That is, a problem to be solved by the present invention is to provide a method for obtaining a polarizing plate which is less prone to cracking even when water adheres thereto.

In order to solve the above problems, the present invention provides the following means.

[1] A polarizing plate in which a polarizing plate protective film is laminated on one surface and a pressure-sensitive adhesive protective film is laminated on the other surface is cut so that a predetermined size is obtained by putting a blade on the surface of the pressure-sensitive adhesive protective film side , And a protective film is laminated on both surfaces.

[2] The method according to [1], wherein, when cutting the polarizing laminate, the upper surface of the pressure-sensitive adhesive protective film is covered with a covering sheet.

[3] The method according to [1] or [2], wherein the polarizing plate is formed of a protective film fixed to the surface of at least one of the polarizer and the polarizer.

[4] The method according to [1] or [2], wherein the polarizing plate is formed of at least one retardation plate and a protective film fixed to the surface of at least one of the polarizer and the polarizer.

According to the polarizing plate manufacturing method of the present invention, it is possible to obtain a polarizing plate in which cracking is less likely to occur even when moisture adheres.

The method for producing a polarizing plate cut to a predetermined size according to the present invention (hereinafter, simply referred to as " the manufacturing method of the present invention ") is a method in which a polarizing plate protective film is laminated on one surface, The polarizing laminate laminated with the protective film is cut by cutting a blade on the surface of the protective film side of the pressure-sensitive adhesive.

(Polarizer protective film)

The polarizing plate protective film is a film for protecting the surface of the polarizing plate from damage, abrasion, and the like. The polarizing plate protective film is bonded to the polarizing plate by weak adhesiveness. As described above, the polarizing plate protective film remains on the surface of the polarizing plate even after the liquid crystal cell and the polarizing plate are bonded, but is peeled off when a general consumer uses the liquid crystal display. The polarizing plate protective film is preferably easy to handle and has transparency to some extent. The polarizing plate protective film is preferably formed of a resin such as a polyethylene-based resin, a polypropylene-based resin, or a polyethylene terephthalate-based resin, and a pressure-sensitive adhesive. The polarizing plate protective film may be a single layer or may have a multilayer structure in which two or more resin layers are laminated. The polarizing plate protective film usually has a thickness of about 40 탆 to about 150 탆, preferably about 45 탆 to 70 탆.

As the polarizing plate protective film, a resin film on which a pressure-sensitive adhesive is coated on the surface and a resin film having self-adhesive property are commercially available. Specific examples of commercially available products include commercially available products such as a surfactant (manufactured by Sun Aikaken Co., Ltd.) having a surface of a polyethylene resin film coated with an adhesive, an E-mask (Nitto Denko Co., (Manufactured by Fujimori Kogyo Co., Ltd.), which is coated with a pressure-sensitive adhesive on the surface of a polyethylene terephthalate resin film, and Toretek (manufactured by Toray Film Kako Co., Ltd.), which is made of a polyethylene resin having self- .

(Adhesive protective film)

The pressure-sensitive adhesive protective film is a film for protecting the pressure-sensitive adhesive layer provided on the surface of the polarizing plate. When the pressure-sensitive adhesive layer is exposed without being protected, dust may adhere to the polarizing plate before the polarizing plate is actually used, or the polarizing plate may stick to an unintended portion. To prevent this, a pressure-sensitive adhesive protective film is used.

The pressure-sensitive adhesive protective film is not particularly limited as long as it is a release-treated plastic film. For example, a film obtained by processing a thermoplastic resin (polyethylene terephthalate, polyethylene naphtholate, polyethylene, polypropylene or the like) And the like. As such a pressure-sensitive adhesive protective film, a commercially available pressure-sensitive adhesive protective film which can be used as a release film usually has a thickness of about 15 μm to 80 μm, preferably about 20 μm to 50 μm.

(Pressure-sensitive adhesive layer)

The polarizing plate of the present invention has a pressure-sensitive adhesive layer on the side where the pressure-sensitive adhesive protective film is laminated. Such a pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive which has been conventionally used for bonding a liquid crystal cell and a polarizing plate. Examples of such a pressure-sensitive adhesive include acrylic, rubber, urethane, silicone, and polyvinyl ether adhesives. Further, an adhesive such as an active energy ray curable type or a thermosetting type may be used. Among these, acrylic pressure-sensitive adhesives having an acrylic resin excellent in transparency, weather resistance, heat resistance and the like as a base polymer are suitable.

The acrylic pressure-sensitive adhesive is not particularly limited, and examples thereof include (meth) acrylic acid ester-based polymers such as butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate and 2-ethylhexyl (Meth) acrylic acid ester as a base polymer. Further, (meth) acryl means "acrylic" or "methacryl". As the monomer constituting the polymer of the copolymer system, a polar monomer is preferably included. Examples of the polar monomer include monomers having a functional group such as a carboxyl group, a hydroxyl group, an amide group, an amino group and an epoxy group, and specific examples thereof include (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, Ethyl, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate and the like.

The acrylic pressure sensitive adhesive may be used alone or in combination with a crosslinking agent. Examples of the cross-linking agent include a polyvalent metal salt forming a carboxylic acid metal salt with a carboxyl group, a polyamine compound forming an amide bond with a carboxyl group, a polyepoxy compound or polyol compound forming an ester bond with a carboxyl group, And polyisocyanate compounds that form amide bonds. Of these, polyisocyanate compounds are suitably used.

The active energy ray-curable pressure-sensitive adhesive is a pressure-sensitive adhesive having a property of curing by irradiation of active energy rays such as ultraviolet rays or electron beams. The pressure-sensitive adhesive has stickiness even before irradiation with active energy rays and adheres to an adherend such as a film, And has the property that the adhesion can be adjusted by curing by irradiation. As the active energy radiation curable pressure sensitive adhesive, an ultraviolet curable pressure sensitive adhesive is preferable. The active energy ray-curable pressure-sensitive adhesive usually contains an acrylic pressure-sensitive adhesive and an active energy ray-polymerizable compound as a main component. In addition, a crosslinking agent may be added, or a photo polymerization initiator or photosensitizer may be added as needed.

In addition to the crosslinking agent, additives such as a natural resin, a synthetic resin, a tackifier resin, an antioxidant, an ultraviolet absorber, a dye, a pigment, a defoaming agent, a corrosion inhibitor and a polymerization initiator good. By using these additives, the adhesive force, cohesive force, viscosity, elastic modulus, glass transition temperature and the like of the pressure-sensitive adhesive can be adjusted.

The pressure-sensitive adhesive layer preferably has a thickness of 1 占 퐉 to 40 占 퐉. It is preferable to apply a thin layer within a range that does not impair the processability and durability of the laminate. In view of maintaining better processability and suppressing the dimensional change of the polarizing plate, the thickness is more preferably 3 m to 25 m. If the thickness of the pressure-sensitive adhesive layer is too small, the pressure-sensitive adhesive property is deteriorated. If the pressure-sensitive adhesive layer is too thick, the pressure-sensitive adhesive is likely to come out from the laminated plate.

(Polarizer)

The polarizing plate has a function of converting natural light into linearly polarized light. In general, the polarizing plate is a lamination of a polarizer protective film fixed on the surface of at least one of a polarizer and a polarizer, and other functional films or functional sheets may be laminated if necessary. Examples of the polarizer include the following (a) and (b).

(a) Adsorption and orientation of a dichroic dye on a film of a polyvinyl alcohol (PVA) resin, a polyvinyl acetate resin, an ethylene / vinyl acetate (EVA) resin, a polyamide resin or a polyester resin.

(b) a polyvinyl alcohol / polyvinylene copolymer having a molecular chain in which a dichroic dehydration product of polyvinyl alcohol (polyvinylene) is oriented in a molecularly oriented polyvinyl alcohol film.

The polyvinyl alcohol-based resin is usually obtained by saponifying a polyvinyl acetate-based resin. The saponification degree is usually 85 mol% or more, preferably 90 mol% or more, and more preferably 99 mol% to 100 mol%. Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and a copolymer with other monomers copolymerizable with vinyl acetate, such as ethylene-vinyl acetate copolymer. Examples of other monomers include unsaturated carboxylic acids, olefins, vinyl ethers, and unsaturated sulfonic acids.

The molecular weight of the polyvinyl alcohol-based resin is not particularly limited, and is preferably about 1,000 to 10,000, and more preferably about 1,500 to 5,000.

The polyvinyl alcohol may be modified. Examples of the modified polyvinyl alcohol include polyvinylformal modified with aldehydes, polyvinyl acetal, polyvinyl butyral, and the like.

As the starting material for the production of the polarizer, an unoriented film of the polyvinyl alcohol-based resin having a thickness of preferably 20 m to 100 m, more preferably 30 m to 80 m is used. The width of the film is preferably from about 1500 mm to about 4000 mm on an industrial scale. This unstretched film is subjected to, for example, a swelling process, a dyeing process, a crosslinking process, and a washing process in this order, uniaxial stretching in a process up to the crosslinking process, and finally drying to obtain a polarizer. The polarizer usually has a thickness of 5 mu m to 50 mu m, preferably 5 mu m to 30 mu m.

Examples of the dichroic dye used in the dyeing step include iodine and organic dyes. Examples of the 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, H, Black B, Black GSP, Yellow 3G, Yellow R, Orange LR, Orange 3R, Scarlet GL, Scarlet KGL, Congo-red, Brilliant Violet BK, Supra Blue G, Supra Blue GL, Supra Orange GL, Direct First Orange S, and First Black. These dichroic dyes may be used alone, or two or more dyes may be used in combination.

As the cross-linking agent used in the cross-linking step, conventionally known materials can be used. Examples thereof include boron compounds such as boric acid and borax, and glyoxal and glutaraldehyde. These crosslinking agents may be used alone or in combination of two or more.

Next, the polarizer protective film will be described. Polarizers are low in strength and prone to tearing. The polarizer protective film is a film for protecting the polarizer and is fixed to at least one of the polarizers.

Examples of the polarizer protective film include films conventionally used in the related art. Examples of the polarizer protective film include a cycloolefin resin film, a cellulose acetate resin film, a polyester resin film (e.g., polyethylene terephthalate, polyethylene naphthalate, Butylene terephthalate and the like), a polycarbonate resin film, an acrylic resin film, and a polypropylene resin film.

The polarizer protective film is preferably transparent and has excellent chemical resistance, more preferably a cellulose acetate resin film. The cellulose acetate resin is a part or completely acetic acid esterified product of cellulose, and examples thereof include triacetyl cellulose (TAC), diacetyl cellulose, and cellulose acetate propionate.

(Manufactured by Fuji Photo Film Co., Ltd.), Fuji Tack (registered trademark) TD80UF (manufactured by Fuji Photo Film Co., Ltd.), Fuji Photo Film (registered trademark) by Fuji Photo Film Co., TD80UZ (manufactured by Fuji Film), KC8UX2M (manufactured by Konica Minolta Opto), and KC4UY (manufactured by Konica Minolta Opto).

The polarizer protective film may be adhered to at least one surface of the polarizer. When the polarizer protective film is fixed to both surfaces of the polarizer, both polarizer protective films may be the same or may be different polarizer protective films. For example, triacetyl cellulose may be fixed on both sides of the polarizer, triacetyl cellulose may be fixed on one side, and another polarizer protective film may be fixed on the other side. The other polarizer protective film is not particularly limited, but a cycloolefin based resin film is preferably used.

The cycloolefin resin is commercially available and is commercially available from, for example, Topas (registered trademark) (manufactured by Ticona), ATON (registered trademark) (manufactured by JSR Corporation), ZEONOR (registered trademark) ZEONEX (registered trademark) (manufactured by Nippon Zeon Co., Ltd.) and APEL (registered trademark) (manufactured by Mitsui Chemicals, Inc.).

When the cycloolefin resin is produced into a film, known methods such as a solvent casting method and a melt extrusion method are suitably used. (Manufactured by Sekisui Chemical Co., Ltd.), SCA40 (manufactured by Sekisui Chemical Co., Ltd.), Zeonoa (registered trademark) film (manufactured by Optesis Co., Ltd.) A commercially available product of the cycloolefin-based resin film produced may be used.

The polarizer protective film usually has a thickness of about 10 to 150 占 퐉, preferably about 20 to 100 占 퐉.

(Retardation plate)

In producing a polarizing plate, a retardation plate is often used as a functional film or a functional sheet to be laminated, if necessary, together with a polarizer and a polarizer protective film. The retardation plate is adopted depending on the characteristics required for the liquid crystal panel and the liquid crystal display device.

When the polarizing plate is used as an elliptically polarizing plate, for example, a 1/4 wavelength plate is provided as the retardation plate. When the polarizing plate is used as a linearly polarizing plate, for example, a biaxial retardation film having an optical compensation function, a non-oriented film having a surface protective function, and the like are employed.

The 1/4 wave plate is a plate (film) showing a phase difference of almost 1/4 wavelength (90 degrees) with respect to any one of the wavelength regions of visible light (380 nm to 780 nm), and linearly polarized light and circularly polarized light And has a function of compensating the viewing angle of the liquid crystal cell.

The material constituting the phase difference plate is not particularly limited and examples thereof include (meth) acrylic resins (methyl methacrylate resins and the like), olefin resins, polyvinyl chloride resins, cellulose resins, styrene resins, acrylonitrile (AS resin), a polyvinyl acetate resin, a polyvinylidene chloride resin, a polyamide resin, a polyacetal resin, a polybutadiene resin, a polybutadiene resin, Based resin, a polycarbonate-based resin, a modified polyphenylene ether resin, a polyester-based resin (such as polyethylene terephthalate and polybutylene terephthalate), a polysulfone-based resin, a polyether sulfone- , A polyimide-based resin, an epoxy-based resin, and an oxetane-based resin. These resins may contain additives in such a range as not to impair transparency and fixability.

When a phase difference plate is used, the phase difference plate may be a single layer or two or more layers. When two or more retardation plates are laminated, different retardation plates may be used using the same retardation plate, but usually different retardation plates are used. In the case of using the same retarder, it is usually used by changing the respective axis angles, but they may be used at the same axis angle. The retardation plate usually has a thickness of about 10 to 100 mu m, preferably about 20 to 80 mu m.

(Lamination step)

A polarizing plate in which a polarizing plate protective film is laminated on one surface and a pressure-sensitive adhesive protective film is laminated on the other surface can be obtained by the above-mentioned polarizing plate protective film, pressure sensitive adhesive protective film, polarizer, polarizer protective film, Or a functional sheet, and is cut into a fabric before the polarizing plate is obtained.

In the polarizing laminate, the polarizer, the polarizer protective film and other functional films or functional sheets are generally adhered with an adhesive or a pressure-sensitive adhesive. The adhesive and the pressure-sensitive adhesive are not limited as long as they do not impair the function of the polarizing plate. For example, an adhesive containing a polyvinyl alcohol resin, an epoxy resin, a urethane resin, a cyanoacrylate resin, an acrylamide resin, And a pressure-sensitive adhesive.

As one of preferable adhesives, an adhesive of a non-solvent type can be mentioned. The adhesive of the solventless form includes a curable compound (monomer, oligomer, or the like) that does not contain a significant amount of solvent but reacts and cures upon irradiation with active energy rays (for example, ultraviolet rays, visible rays, , An adhesive exhibiting a fixing function by curing of a curable compound. These adhesives usually contain a polymerization initiator together with a curable compound.

The laminate as the raw material is constituted according to the intended use of the polarizing plate, and examples thereof include a polarizing plate protective film / polarizing plate (polarizer protective film / polarizer) / pressure-sensitive adhesive layer / pressure-sensitive adhesive protective film, a polarizing plate protective film / polarizing plate Polarizer / retarder / retarder) / pressure-sensitive adhesive layer / pressure-sensitive adhesive protective film, polarizer protective film / polarizer (polarizer protective film / polarizer / first retardation plate / second retardation plate) Protective film / polarizer (polarizer protective film / polarizer / polarizer protective film / retarder) / pressure-sensitive adhesive layer / pressure-sensitive adhesive protective film / polarizer protective film / polarizer protective film Film, a polarizing plate protective film / polarizing plate (polarizer protective film / polarizer / polarizer protective film / first retardation plate / second retardation plate) / pressure sensitive adhesive layer / pressure sensitive adhesive protective film. Further, the polarizer, the polarizer protective film and the substrate of the adhesive or pressure-sensitive adhesive for fixing the retarder are not shown.

The thickness of the laminate (raw material) thus obtained is appropriately set according to the use of the polarizing plate as a product, and is usually about 100 to 600 占 퐉, preferably about 150 to 400 占 퐉.

The laminate (raw material) is usually produced by using a long sheet wound on a roll as a raw material and subjecting it to various treatments continuously or intermittently. In the present invention, usually, as a step during the production of a laminate (raw fabric), the laminate is cut so as to become a short laminate before the cutting step. The obtained laminated body (raw material) is larger than the desired polarizing plate and has a size capable of obtaining a plurality of polarizing plates, for example, 4 to 80 sheets.

(Cutting process)

Next, the cutting step in the manufacturing method of the present invention will be described.

The cutting step is a step of cutting the laminate (raw end) to obtain a polarizing plate of a predetermined dimension in which a protective film is laminated on both surfaces. In the manufacturing method of the present invention, in the cutting step, the laminate (raw material) is cut by cutting a blade on the surface of the protective film side of the pressure-sensitive adhesive. A polarizer can be obtained in which a blade is put on the surface of the pressure-sensitive adhesive protective film side and the laminate (raw material) is cut so that cracks are unlikely to occur even when water adheres. As shown in the comparative example to be described later, when a laminate (raw material) is cut by cutting a blade on the surface of the polarizing plate protective film side, cracks are liable to occur due to adhesion of water. As described above, when cutting the laminate (raw fabric), the ease of occurrence of cracks due to the adhesion of moisture varies depending on which surface the blade is laid on.

Here, the " surface on the side of the pressure-sensitive adhesive protective film " means the outermost surface on the side where the pressure-sensitive adhesive protective film is present in the layer of the polarizer, and when the layered product In the case of cutting another object (for example, a cover sheet described later) on a laminate (raw material) on which the adhesive protective film is placed on the upper side, the upper surface of the object.

As described above, if there is a defect in the polarizing plate protective film, the entire bonded product (liquid crystal panel) obtained is subjected to disposal in the defect inspection in the liquid crystal panel manufacturing factory. Therefore, at the time of producing the polarizing plate, Care must be taken to avoid scarring. On the other hand, for a pressure-sensitive adhesive protective film to be peeled off when a polarizing plate is adhered to a liquid crystal cell, slight scratches are allowed. Therefore, at the time of manufacturing the polarizing plate in the present invention, it is preferable to treat the polarizing plate protective film so that the polarizing plate protective film is usually on the upper surface side as in the conventional method, and to cut the upper and lower sides of the laminate Do. In this cutting step, care must be taken to prevent scratches on the lower surface of the polarizing plate protective film.

It is preferable to cover the upper surface of the pressure-sensitive adhesive protective film with a covering sheet so as to prevent contamination (such as full contamination) on the surface when cutting the laminate (raw end).

The cover sheet is not limited as long as it is a material sheet which can be cut together with the laminate (fabric), and examples of the cover sheet include films made of resin (polyethylene film, polypropylene film, etc.), cloth (woven fabric, And the like. When the upper surface of the pressure sensitive adhesive protective film is covered with the covering sheet, it is preferable that the covering sheet is put on the upper surface of the pressure sensitive adhesive protective film to remove air bubbles between the pressure sensitive adhesive protective film and the covering sheet.

The laminate (raw material) is cut by a conventional cutting machine, and is not particularly limited. For example, in a batch mode, a laminate (raw material) having a size according to a cutter (typically about 500 mm x 500 mm to 1000 mm x 1000 mm) is prepared and the surface of the pressure- ) Is fixed to the cutter, and if necessary, covered with a covering film, and cut to a desired size. Further, in the manufacturing method of the present invention, since the laminate (raw material) is cut by cutting the blade on the surface of the pressure-sensitive adhesive protective film side, the blade used for cutting is preferably a blade (so-called guillotine blade) .

Example

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

(Example 1)

A polarizer protective film (thickness: 44 占 퐉) made of triacetyl cellulose having a hard coat layer on its surface was attached to one surface of a polarizer (thickness of 29 占 퐉) having iodine adsorbed and oriented on long polyvinyl alcohol with a polyvinyl alcohol resin adhesive Respectively. A polarizing plate protective film was bonded to the surface of the polarizer protective film. The polarizing plate protective film used was a polyethylene terephthalate resin film (thickness 49 탆) coated with an acrylic pressure-sensitive adhesive. Then, an acrylic pressure-sensitive adhesive was applied to the other surface of the polarizer so as to have a thickness of 15 mu m to obtain a layered product A.

Acrylic pressure-sensitive adhesive was applied on one surface of a retardation plate (Sumikitrite SES430270, thickness 33 占 퐉, manufactured by Sumitomo Chemical Co., Ltd.) having an in-plane retardation of 270 nm made of a stretched film of norbornene resin so as to have a thickness of 5 占 퐉. The retardation plate having an in-plane retardation of 270 nm is referred to as a " first retardation plate ".

The surface of the first retardation plate coated with the acrylic pressure-sensitive adhesive of the laminate A was bonded to the surface to which the pressure-sensitive adhesive was not applied.

Further, an acrylic pressure-sensitive adhesive was applied on one surface of a retardation plate (Sumikitrite SES430140, thickness 28 占 퐉, manufactured by Sumitomo Chemical Co., Ltd.) having an in-plane retardation of 140 nm so as to have a thickness of 15 占 퐉 to form a pressure-sensitive adhesive layer. The retardation plate having an in-plane retardation of 140 nm is referred to as a " second retardation plate ". On the pressure-sensitive adhesive layer formed on the second phase difference plate, a pressure-sensitive adhesive protective film (thickness of 38 mu m) formed of polyethylene terephthalate resin was bonded. The surface of the thus-obtained "second retardation plate to which the pressure-sensitive adhesive protective film was bonded" on which the pressure-sensitive adhesive layer was not formed was bonded with the surface to which the acrylic pressure-sensitive adhesive of the "first retardation plate laminated to the laminate A" .

Each layer was laminated in this way and the obtained laminate was cut to obtain a protective film of polarizing plate protective film / polarizer protective film / polarizer / acrylic pressure sensitive adhesive / first retardation plate / acrylic pressure sensitive adhesive / second retardation plate / pressure sensitive adhesive layer / pressure sensitive adhesive protective film (Raw material) (800 mm x 500 mm, thickness 256 m) having a laminated structure was obtained.

Subsequently, the obtained laminate (fabric) was put on the folded-back laminate of the cutter so that the adhesive protective film was the upper face, and the end was fixed with a tape. The upper part of the laminate (fabric) fixed with the tape was covered with a polyethylene film and was manually pressed to remove air bubbles formed between the pressure-sensitive adhesive protective film and the polyethylene film, and then the guillotine blade was put on a polyethylene film to form a laminate ) Was cut to obtain a polarizing plate of 90 mm 占 51 mm.

The obtained polarizing plate was dried at 80 캜 for 1 hour, dried and allowed to stand at 23 캜 for 15 minutes under a humidity of 55% RH. Subsequently, the polarizing plate was immersed in water (23 DEG C) for 30 minutes, and the presence of cracks was observed using a loupe and a microscope, but no cracks were observed.

(Example 2)

A polarizing plate was obtained in the same manner as in Example 1 except that the laminate (fabric) obtained in Example 1 was cut without being covered with a polyethylene film.

With respect to the obtained polarizing plate, the presence or absence of cracks was observed in the same procedure as in Example 1, but no cracks were observed at all.

(Comparative Example 1)

A polarizing plate was obtained in the same manner as in Example 1, except that the laminate (raw material) obtained in Example 1 was placed on the folded laminate of the cutter so that the polarizing plate protective film was on the upper face and cut without covering with a polyethylene film.

With respect to the obtained polarizing plate, the presence or absence of cracks was observed using a loupe and a microscope in the same procedure as in Example 1, and a large number of fine cracks were generated in the periphery of the polarizing plate.

The polarizing plate obtained by the production method of the present invention hardly causes cracks even when water adheres thereto, and is used, for example, in a portable information terminal such as a cellular phone or a smart phone.

Claims (4)

A polarizing plate protective film laminated on one surface and a pressure sensitive adhesive protective film laminated on the other surface of the pressure sensitive adhesive laminate is cut so as to have a predetermined size by putting a blade on the surface of the pressure sensitive adhesive protective film side, Wherein a protective film is laminated on the polarizing plate. The method according to claim 1, wherein when the polarizing laminate is cut, the upper surface of the pressure-sensitive adhesive protective film is covered with a cover sheet. The method according to claim 1 or 2, wherein the polarizing plate is formed of a protective film fixed on at least one surface of the polarizer and the polarizer. The method according to claim 1 or 2, wherein the polarizing plate is formed of at least one retardation plate and a protective film fixed to the surface of at least one of the polarizer and the polarizer.