JP2005326531A - Polarizing plate equipped with protecting film, manufacturing method therefor, and image display device using polarizing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarizing plate equipped with a protecting film in which the occurrence of a curl is suppressed, and a manufacturing method therefor. <P>SOLUTION: The polarizing plate 31 with a protecting film is formed with a protecting film 22 on one surface of a polarizing plate 21 with an adhesive which is constituted by laminating an adhesive layer 12 and a separator 13 on one surface of a polarizing plate 11, the one surface different from the surface on which the adhesive layer 12 and the separator 13 are laminated, wherein the water content of the polarizing plate 11 before the adhesive layer 12 and the separator 13 are laminated is 2.85wt% to 3.8wt% and also the water content of the polarizing plate 21 with the adhesive is 2wt% to 2.7wt%. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polarizing plate with a protective film having excellent shape stability, a method for producing the same, and an image display device using the same.

  The polarizing plate is produced by attaching a protective layer such as a triacetyl cellulose (TAC) film to a polarizer dyed with dichroic iodine or dye on a PVA (polyvinyl alcohol) film using an adhesive. As the protective layer, it is preferable to use a layer without curling, but curling inevitably occurs in the manufacturing process. Further, with the occurrence of curling, the curling usually occurs also in the final product (polarizing plate with protective film).

  By the way, in recent years, polarizing plates are becoming larger and larger. For this reason, a case has arisen where curling of the polarizing plate causes a problem in bonding to a liquid crystal cell, for example. For this reason, suppressing curling of a polarizing plate as much as possible has been highlighted as an important issue.

  For example, when a protective film is bonded to a polarizing plate with an adhesive, the polarizing plate with an adhesive curls on the plus (+) side (when the adhesive layer and separator are laminated on the upper side of the polarizing plate, If it has been curled), a polarizing plate with a protective film is added to the positive (+) side by attaching a protective film to the surface of the polarizing plate opposite to the surface on which the adhesive layer and separator are laminated. It curls in. Conversely, if the polarizing plate with an adhesive curls on the negative (-) side (if the adhesive layer and separator are laminated on the upper side of the polarizing plate, it will curl in a concave shape), the protective film Even when the curl of the polarizing plate with the protective film is kept within the standard by a method such as tension adjustment, a large curl is generated after the separator is peeled off.

  Accordingly, in order to stably reduce the curl of the polarizing plate as the final form, it is necessary to make a curl suppressed as much as possible when manufacturing the polarizing plate. As a method for suppressing the occurrence of curling, conventionally, a method has been adopted in which the tension of the protective layer of the polarizing plate is adjusted to suppress the curling of the polarizing plate (for example, see Patent Document 1).

However, such a method alone cannot completely prevent curling in the final product state in which the protective film, the pressure-sensitive adhesive layer and the separator are laminated. Moreover, there is a problem that curling occurs when the separator is peeled off even in the stage where the final product is actually used.
JP 2004-117482 A

  The present invention has been made to solve the above-described conventional problems, and its purpose is to bond a protective film to a polarizing plate and to peel a separator laminated on the polarizing plate. However, it is an object to provide a polarizing plate that suppresses the occurrence of curling as much as possible, a manufacturing method thereof, and an image display device including the same.

  In order to solve the above-described conventional problems, the inventors of the present application have made extensive studies on a polarizing plate, a method for manufacturing the polarizing plate, and an image display device including the polarizing plate. As a result, if the curl of the polarizing plate has an asymmetrical configuration (for example, an intermediate product before being the final product (polarizing plate with adhesive)), the moisture content of the original polarizing plate is curled. It was found that it is related to fluctuations. More specifically, in the configuration in which the separator and the polarizing plate are bonded via the pressure-sensitive adhesive layer, the polarizing plate itself expands or contracts as the polarizing plate absorbs or releases moisture. It was found that the curl of the polarizing plate fluctuates. From such knowledge, the control of the moisture content of the original polarizing plate itself in the manufacturing process of the polarizing plate makes it asymmetric even after the application of the adhesive composition to form the adhesive layer. Curling of a polarizing plate (a polarizing plate having a different laminate on one side and the other side) can be adjusted, and the present invention has been completed.

  That is, in order to solve the above-mentioned problem, the polarizing plate with a protective film according to the present invention is a pressure-sensitive adhesive layer of a polarizing plate with a pressure-sensitive adhesive constituted by laminating a pressure-sensitive adhesive layer and a separator on one surface of the polarizing plate. And a polarizing plate with a protective film in which a protective film is provided on the surface on which the separator is laminated and the other surface, and the moisture content of the polarizing plate before lamination of the pressure-sensitive adhesive layer and the separator is 2. 85 wt% to 3.8 wt%, and the moisture content of the polarizing plate with an adhesive is 2 wt% to 2.7 wt%.

  The polarizing plate preferably includes a polarizer and a protective layer having a thickness of 100 μm or less on at least one surface of the polarizer.

  Further, the protective layer is preferably made of a triacetyl cellulose film.

  In order to solve the above-mentioned problems, an optical film according to the present invention includes the polarizing plate with a protective film or the polarizing plate with a protective film after separation of the separator, and an optical functional layer. .

  In order to solve the above problems, a liquid crystal display device according to the present invention includes the polarizing plate with a protective film, the polarizing plate with a protective film after peeling the separator, or an optical film, and a liquid crystal cell. It is characterized by.

  In order to solve the above problems, an image display device according to the present invention includes the polarizing plate with a protective film or the polarizing plate with a protective film after peeling the separator, an optical film, or a liquid crystal display element. It is characterized by.

Moreover, in order to solve the above-mentioned subject, the manufacturing method of the polarizing plate with an adhesive concerning the present invention of the polarizing plate with an adhesive constituted by laminating an adhesive layer and a separator on one side of a polarizing plate On the other side is a method for producing a polarizing plate with a protective film provided with a protective film,
A step of adjusting the moisture content of the polarizing plate to 2.85 wt% to 3.8 wt%, and laminating an adhesive layer and a separator on one surface of the polarizing plate, the moisture content is 2 wt% to 2.7 wt%. % Polarizing plate with adhesive, and a step of attaching a protective film to the other surface of the polarizing plate. At this time, the order of the steps is not limited as long as the moisture content is satisfied. However, after the polarizing plate is made into a polarizing plate with an adhesive, it is preferable to make a polarizing plate with a protective film.

  The step of adjusting the moisture content of the polarizing plate is preferably performed under the condition of leaving for 72 hours or more in an environment of a temperature of 23 ± 5 ° C. and a humidity of 40 to 65% RH.

  The step of adjusting the moisture content of the polarizing plate is preferably performed by immersing the polarizing plate in water.

  In order to solve the above-mentioned problem, the method for producing a polarizing plate with a protective film according to the present invention is a method for producing a polarizing plate with an adhesive in which an adhesive layer and a separator are laminated on one surface of the polarizing plate. And adjusting the moisture content of the polarizing plate to 2.85 wt% to 3.8 wt%, and laminating an adhesive layer and a separator on one surface of the polarizing plate, so that the moisture content is 2 wt% to 2 wt%. And a step of producing a 7 wt% polarizing plate with an adhesive.

  The step of adjusting the moisture content of the polarizing plate is preferably performed under the condition of leaving for 72 hours or more in an environment of a temperature of 23 ± 5 ° C. and a humidity of 40 to 65% RH.

  The step of adjusting the moisture content of the polarizing plate is preferably performed by immersing the polarizing plate in water.

  In order to solve the above problems, the polarizing plate with an adhesive according to the present invention is obtained by the method for producing a polarizing plate with an adhesive described above.

  In order to solve the above problems, the polarizing plate with a protective film according to the present invention is obtained by the method for producing a polarizing plate with a protective film as described above.

  In order to solve the above-described problems, an optical film according to the present invention is characterized by having the polarizing plate with an adhesive or the polarizing plate with a protective film described above and an optical functional layer.

  In order to solve the above-described problems, an image display device according to the present invention includes the polarizing plate with an adhesive, the polarizing plate with a protective film, or the optical film described above.

  The polarizing plate with a protective film according to the present invention has a configuration in which one is a polarizing plate and the other is a separator through the pressure-sensitive adhesive layer in the state of the polarizing plate with the adhesive before bonding the protective film. . In general, this structure is called aging of the pressure-sensitive adhesive layer and is stored in this state for a certain period. However, since the polarizing plate and the separator are made of materials having different moisture absorptions, the degree of shape change due to expansion or contraction due to moisture absorption is different, and the structure tends to cause curling. In the present invention, the moisture content of the polarizing plate before lamination of the pressure-sensitive adhesive layer and the separator is 2.85 wt% to 3.8 wt%, and the moisture content of the polarizing plate with an adhesive is 2 wt% to 2.7 wt%. Since it has a certain configuration, the degree of shape change due to expansion or contraction due to moisture absorption is not greatly different. Thereby, the polarizing plate with a protective film which suppressed generation | occurrence | production of a curl as much as possible in the case of bonding of a protective film and peeling of a separator is obtained.

  Moreover, in the method for producing a polarizing plate with an adhesive according to the present invention, by adjusting the moisture content of the polarizing plate before laminating the adhesive layer and the separator to 2.85 wt% to 3.8 wt%, A polarizing plate with an adhesive having a moisture content of 2 wt% to 2.7 wt% can be produced. With such a polarizing plate with a pressure-sensitive adhesive, curling can be suppressed as much as possible.

  Moreover, in the method for producing a polarizing plate with a protective film according to the present invention, the moisture content is adjusted to 2.85 wt% to 3.8 wt% so that the moisture content is 2 wt% to 2.7 wt%. A polarizing plate with an adhesive is prepared. When the polarizing plate with an adhesive having such a moisture content is used, a polarizing plate with a protective film that suppresses the occurrence of curling as much as possible can be produced when the protective film is bonded and when the separator is peeled off. . Furthermore, according to the present invention, it is particularly effective in suppressing curling in the width direction during manufacturing.

  An embodiment of the present invention will be described with reference to FIGS. However, parts unnecessary for the explanation are omitted, and there are parts shown enlarged or reduced for easy explanation.

  FIG. 1 is a cross-sectional view showing a schematic configuration of a polarizing plate according to the present embodiment. FIG. 2 is a cross-sectional view showing a schematic configuration of a polarizing plate with an adhesive according to the present embodiment. FIG. 3 is a cross-sectional view illustrating a schematic configuration of a polarizing plate with a protective film according to the present embodiment.

  As shown in FIG. 1, the polarizing plate 11 according to the present embodiment has a structure in which protective layers 2 are provided on both surfaces of a polarizer 1. Moreover, the polarizing plate 21 with an adhesive according to the present embodiment has a structure in which an adhesive layer 12 and a separator 13 are sequentially laminated on a polarizing plate 11 as shown in FIG. Furthermore, as shown in FIG. 3, the polarizing plate 31 with a protective film according to the present embodiment has the polarizing plate 21 with a pressure-sensitive adhesive and the protective film 22 opposite to the surface on which the pressure-sensitive adhesive layer 12 and the like are provided. In this structure, the side surface is bonded as an adhesive surface. In the present embodiment, the polarizing plate 11 will be described by taking as an example a structure in which the protective layer 2 is provided on both surfaces of the polarizer 1, but the present invention is not limited to this. That is, the polarizing plate 11 according to the present invention only needs to have a configuration in which the protective layer 2 is provided on at least one surface of the polarizer 1.

  As the polarizer 1 in the polarizing plate 11, an appropriate one that can obtain light in a predetermined polarization state can be used. The polarizer 1 is not particularly limited. For example, iodine and / or a hydrophilic polymer film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, and an ethylene / vinyl acetate copolymer partially saponified film are used. Examples thereof include a polyene oriented film such as a film obtained by adsorbing and stretching a dichroic dye, a polyvinyl alcohol-based dehydrated product, or a polyvinyl chloride dehydrochlorinated product. Among these polarizers 1, a polarizer 1 made of a dichroic substance such as an iodine-adsorbed stretched polyvinyl alcohol film or a dichroic dye is particularly preferable. This is because linearly polarized light having a high degree of polarization can be obtained.

  A polarizer obtained by dyeing a polyvinyl alcohol film with iodine and uniaxially stretching it can be produced, for example, by dyeing polyvinyl alcohol in an aqueous solution of iodine and stretching it 3 to 7 times the original length. If necessary, it can be immersed in an aqueous solution of boric acid or potassium iodide. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. In addition to washing the polyvinyl alcohol film surface with dirt and anti-blocking agents by washing the polyvinyl alcohol film with water, it also has the effect of preventing unevenness such as uneven coloring by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. The film can be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

  Further, the thickness of the polarizer 1 is not particularly limited. However, about 5 to 80 μm is common.

  As a material for forming the protective layer 2, a polymer film excellent in transparency, mechanical strength, thermal stability, isotropy and the like is preferably used. Specifically, for example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, styrene polymers such as polystyrene and acrylonitrile / styrene copolymer (AS resin), cellulose polymers such as diacetyl cellulose and triacetyl cellulose, and polyethers. Examples include sulfone polymers, polycarbonate polymers, polyamide polymers, polyimide polymers, polyolefin polymers, and acrylic polymers such as polymethyl methacrylate. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above Examples include polymer blends. Other examples include acrylic, urethane-based, acrylic-urethane-based, epoxy-based, and silicone-based thermosetting or ultraviolet curable resins.

  Moreover, the polymer film described in JP-A-2001-343529 (WO01 / 37007), for example, (A) a thermoplastic resin having a substituted and / or unsubstituted imide group in the side chain, and (B) a substitution in the side chain And / or a resin composition containing a non-substituted phenyl and a thermoplastic resin having a nitrile group. A specific example is a film of a resin composition containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer. As the film, a film made of a mixed extruded product of the resin composition or the like can be used. Since these films have a small phase difference and a small photoelastic coefficient, problems such as unevenness due to the distortion of the polarizing plate can be eliminated, and since the moisture permeability is small, the humidification durability is excellent.

  As the protective layer 2, a layer having a phase difference as small as possible is better. In consideration of such viewpoints, polarization characteristics, durability, and the like, it is preferable to use a cellulosic polymer. Furthermore, among the cellulose polymers, triacetyl cellulose is preferable. Moreover, you may use the protective layer 2 in which the surface was formed in the fine concavo-convex structure by containing microparticles | fine-particles.

Further, the thickness of the protective layer 2 is preferably 100 μm or less, and more preferably 60 μm or less. For example, in the case of a thin polarizing plate, triacetyl cellulose (TAC) having a thickness of about 40 μm can be used. In this case, it is known that the curl suppressing effect of the present invention is higher than that of a normal polarizing plate (TAC having a thickness of 80 μm). This is because the total thickness (thickness of the polarizing plate 11) is thin, and it is considered that the total thickness (the thickness of the polarizing plate 11) is more susceptible to curling due to moisture variation of the polarizing plate. The moisture permeability of the protective layer 2 is preferably 400 to 1000 g / m ² · 24 h. When a polarizing plate having a protective layer having a relatively high moisture permeability is used, the effect of suppressing curling of the present invention is high. The moisture permeability is the number of g of water vapor passing through a sample of 1 m ² in 24 hours with a relative humidity difference of 40 ° C. and 90% according to a moisture permeability test (cup method) of JIS Z0208.

  Moreover, each protective layer 2 provided on both surfaces of the polarizer 1 may be formed of the same polymer material, or may be formed of different polymer materials.

  Here, an adhesive may be used for bonding the polarizer 1 and the protective layer 2 together. Although it does not restrict | limit especially as an adhesive agent, An isocyanate type adhesive agent, a polyvinyl-alcohol-type adhesive agent, a gelatin-type adhesive agent, a vinyl-type latex type, water-based polyester etc. can be illustrated.

  The adhesive further includes a silane coupling agent, a coupling agent such as a titanium coupling agent, various tackifiers, an ultraviolet absorber, an antioxidant, a heat stabilizer, a hydrolysis stabilizer, and the like. Etc. can also be blended.

  Further, the surface of the protective layer 2 to which the polarizer 1 is not bonded may be subjected to a process for forming a hard coat layer, an antireflection process, an antisticking process, or a process for the purpose of diffusion or antiglare.

  The hard coat treatment is performed for the purpose of preventing scratches on the surface of the polarizing plate 11. For example, it can be formed by a method of adding a cured film excellent in hardness, slipping property, etc. with an appropriate ultraviolet curable resin such as acrylic or silicone to the surface of the protective layer 2. The antireflection treatment is performed for the purpose of preventing reflection of external light on the surface of the polarizing plate 11, and can be achieved by forming an antireflection film or the like according to the conventional art. Further, the anti-sticking treatment is performed for the purpose of preventing adhesion with an adjacent layer.

  The anti-glare treatment is performed for the purpose of preventing the external light from being reflected on the surface of the polarizing plate 11 and hindering the viewing of the light transmitted through the polarizing plate. For example, it can be formed by imparting a fine concavo-convex structure to the surface of the protective layer 2 by an appropriate method such as a roughening method by a sandblasting method or an embossing method or a blending method of transparent fine particles. Examples of the fine particles to be included in the formation of the surface fine concavo-convex structure include conductive materials made of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, and the like having an average particle diameter of 0.5 to 20 μm. In some cases, transparent fine particles such as inorganic fine particles, organic fine particles made of a crosslinked or uncrosslinked polymer, and the like are used. When forming the surface fine uneven structure, the amount of fine particles used is generally about 2 to 70 parts by weight, preferably 5 to 50 parts by weight, based on 100 parts by weight of the transparent resin forming the surface fine uneven structure. The antiglare layer may also serve as a diffusion layer (viewing angle expanding function or the like) for diffusing the light transmitted through the polarizing plate to expand the viewing angle.

  The antireflection layer, antisticking layer, hard coat layer, diffusion layer, antiglare layer, etc. can be provided on the protective layer 2 itself, and separately provided as a separate optical functional layer from the protective layer 2. You can also.

  For example, when the polarizing plate 31 with a protective film according to the present embodiment is applied to a liquid crystal display device, the pressure-sensitive adhesive layer 12 is a polarizing plate with a protective film on a glass substrate constituting a liquid crystal cell in the liquid crystal display device. This is for attaching the plate 31.

  As the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 12, it is possible to use any acrylic, synthetic rubber-based, or rubber-based pressure-sensitive adhesive that can form the pressure-sensitive adhesive layer 12 that is releasably attached to the surface of the polarizing plate 11. However, an acrylic pressure-sensitive adhesive that can easily control the adhesive strength depending on the composition is desirable.

  As an acrylic adhesive, it is preferable that the weight average molecular weight of the base polymer is about 300,000-2,500,000. As the monomer used in the acrylic polymer that is the base polymer of the acrylic pressure-sensitive adhesive, various alkyl (meth) acrylates can be used. Specific examples of such alkyl (meth) acrylates include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and the like. Can be used alone or in combination. In addition, it is preferable to use a small amount of (meth) acrylic acid instead of a part of the alkyl (meth) acrylate in order to impart polarity to the resulting acrylic polymer. Furthermore, glycidyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, N-methylol (meth) acrylamide and the like may be used in combination as the crosslinkable monomer. Further, if desired, other copolymerizable monomers such as vinyl acetate and styrene may be used in combination as long as the adhesive properties of the acrylic polymer are not impaired.

  The pressure-sensitive adhesive can contain a crosslinking agent. Examples of the crosslinking agent include polyisocyanate compounds, polyamine compounds, melamine resins, urea resins, and epoxy resins. Furthermore, a tackifier, a plasticizer, a filler, an antioxidant, an ultraviolet absorber, a silane coupling agent, and the like can be appropriately used for the pressure-sensitive adhesive as necessary.

  The separator 13 is for protecting the pressure-sensitive adhesive layer 12. Examples of the separator 13 include the same polymer film, rubber sheet, paper, cloth, non-woven fabric, net, foamed sheet, metal foil, and laminates thereof as the material forming the protective layer 2. Further, the adhesive surface of the separator 13 with the pressure-sensitive adhesive layer 12 may be coated with an appropriate release agent such as silicone, long-chain alkyl, fluorine, or molybdenum sulfide, if necessary.

  The protective film 22 is not particularly limited, and a film in which an adhesive layer is formed on a conventionally known base film can be employed. As the adhesive layer, a layer made of an adhesive or a pressure-sensitive adhesive can be appropriately employed depending on the application. For example, what has the light peeling adhesive layer stuck on the single side | surface of the base film comprised from the said polymer film so that peeling with respect to the surface of the polarizing plate 21 with an adhesive is mentioned.

  The base film is not particularly limited, and examples thereof include polyester resins, cellulose resins, acetate resins, polyether sulfone resins, polycarbonate resins, polyamide resins, polyimide resins, and polyolefin resins. Examples thereof include transparent polymers such as resins and acrylic resins. The base film can be used as a laminate of one kind or two or more kinds of film materials, and a stretched product of the base film can also be used. Although it does not restrict | limit especially about the thickness of a base film, Generally, it is 500 micrometers or less, Preferably it is about 10-200 micrometers.

  Although the adhesive which comprises the said contact bonding layer is not specifically limited, For example, any adhesive of an acrylic type, a synthetic rubber type, and a rubber type can be used. Among these, an acrylic pressure-sensitive adhesive that can easily control the adhesive force depending on the composition is desirable. As the pressure-sensitive adhesive, a crosslinking agent, a tackifier, a plasticizer, a filler, an antioxidant, an ultraviolet absorber, a silane coupling agent, and the like can be appropriately used as necessary. The adhesive layer can be formed by a transfer method, a direct copy method, a coextrusion method, or the like. The thickness (dry film thickness) of the adhesive layer is not particularly limited, but is usually about 5 to 50 μm.

  Moreover, the peeling process layer can be formed in the protective film 22 on the surface on the opposite side to the formation surface of the adhesive layer of the said base film. Although it does not restrict | limit especially as a forming material of a peeling process layer, For example, a silicone type release agent, a long-chain alkyl type release agent, etc. are mentioned. The thickness of the release treatment layer is not particularly limited, but is usually about 50 μm or less, preferably 25 to 40 μm.

  Next, the manufacturing method of the polarizing plate 21 with an adhesive and the polarizing plate 31 with a protective film according to the present invention will be described.

  The polarizing plate 21 with the pressure-sensitive adhesive according to the present invention includes a step of adjusting the moisture content of the polarizing plate 11 so that the moisture content of the polarizing plate 11 is in the range of 2.85 wt% to 3.8 wt%, and The pressure-sensitive adhesive layer 12 and the separator 13 are sequentially laminated on one surface of the substrate, and the pressure-sensitive adhesive-attached polarizing plate 21 having a moisture content of 2 wt% to 2.7 wt% is manufactured. Moreover, the manufacturing method of the polarizing plate 31 with a protective film which concerns on this invention includes the process of bonding the protective film 22 to the other surface of the said polarizing plate 11 in addition to the said process.

  In the step of adjusting the moisture content of the polarizing plate 11, for example, a method for producing a polarizing plate having the saturated moisture content by storing for a long time in the same humidity environment as the intended saturated moisture content, At the time of production, a method of producing a polarizing plate, a method of immersing in water, a method of spraying water, or the like can be employed so as to achieve a desired moisture content by adjusting the drying conditions.

  When the polarizing plate 11 is stored for a certain period, the polarizing plate 11 having a moisture content in the above range is obtained by leaving it for 72 hours or more in an environment of a temperature of 23 ± 5 ° C. and a humidity of 40 to 65% RH, for example. It is done. The method of adjusting the moisture content by storing such a polarizing plate 11 in the adjustment atmosphere for a certain period of time adjusts the moisture content gently and uniformly without abruptly changing the physical properties of the polarizing plate 11. Therefore, it can be used preferably with little change in optical characteristics. Further, as described above, the method of adjusting the moisture content by immersing in water is a preferable method because the moisture content can be easily and uniformly adjusted in a series of production steps. The type of water to be immersed, the presence / absence of additives, temperature and immersion time are not particularly limited, but it is immersed in pure water at a temperature of 10 to 80 ° C. so as to obtain the moisture content, and the immersion time is 1 second. What is necessary is just to adjust suitably within the range for 10 minutes. Furthermore, the moisture content may be adjusted in a high humidity environment where the relative humidity at a temperature of 10 to 80 ° C. is about 80 to 100% RH without being immersed in water.

  By setting the moisture content of the polarizing plate 11 within the above range before laminating the pressure-sensitive adhesive layer 12 and the like, curling occurs before the polarizing plate 21 with the pressure-sensitive adhesive 21 and the protective film 22 are bonded together and after the separator 13 is peeled off. Can be suppressed as much as possible. Further, the moisture content of the polarizing plate 11 is preferably 2.95 to 3.70 wt%, more preferably 3.05 to 3.65 wt%. Moreover, the moisture content of the polarizing plate 21 with an adhesive is preferably 2.05 to 2.60 wt%, and more preferably 2.10 to 2.50 wt%.

  When the moisture content of the polarizing plate 11 is less than 2.85 wt%, or when the moisture content of the polarizing plate 21 with adhesive is less than 2 wt%, the polarizing plate 11 in which the adhesive layer 12 is formed by application of an adhesive or the like. Absorbs moisture during the temporary storage for aging of the pressure-sensitive adhesive layer 12. For this reason, the polarizing plate with the separator 13 is not preferable because curling ((−) curling) occurs so that the separator 13 is concave.

  In the conventional method, in the case of curling, the product itself can be curled to some extent by adjusting the tension when the polarizing plate with adhesive and the protective film are bonded. . However, if the protective film is strongly applied to correct the curl, the curl becomes even larger when the separator is peeled off, resulting in difficulty in use on the user side.

  On the other hand, when the moisture content of the polarizing plate 11 before forming the adhesive layer 12 is larger than 3.8 wt%, or when the moisture content of the polarizing plate 21 with the adhesive is larger than 2.7 wt%, At the time of temporary storage, curling ((+) curling) occurs so that the separator 13 side is convex, which is not preferable. Furthermore, when a protective film is applied to the polarizing plate with the pressure-sensitive adhesive that has been curled, the curl is further increased, and the curl of the product exceeds a predetermined standard.

  In the present invention, a step of measuring whether or not the moisture content of the polarizing plate 11 is in the range of 2.85 wt% to 3.8 wt% may be included. When the moisture content of the polarizing plate 11 is within the numerical range as a result of the measurement of the moisture content, there is no need to adjust the moisture content.

  The method for laminating the pressure-sensitive adhesive layer 12 and the separator 13 on the polarizing plate 11 to produce the pressure-sensitive adhesive-attached polarizing plate 21 is not particularly limited, and various conventionally known methods can be employed. For example, the prepared pressure-sensitive adhesive composition is applied on the polarizing plate 11 so as to have a predetermined film thickness, and after forming the pressure-sensitive adhesive layer 12, a method of bonding the separator 13 on the pressure-sensitive adhesive layer 12, The prepared pressure-sensitive adhesive composition is coated on the separator 13 so as to have a predetermined film thickness, and after the pressure-sensitive adhesive layer 12 is formed, the polarizing plate 11 is bonded onto the pressure-sensitive adhesive layer 12. When the pressure-sensitive adhesive layer 12 is formed from the pressure-sensitive adhesive composition as described above, it is generally necessary to heat and dry. However, when the pressure-sensitive adhesive layer 12 is formed on the polarizing plate 11, the water content of the polarizing plate 11 taking this into consideration. Since it is necessary to adjust the rate, a method of bonding the polarizing plate 11 after forming the pressure-sensitive adhesive layer 12 on the separator 13 is simple and more preferably used. On the other hand, when the method of directly forming the pressure-sensitive adhesive layer 12 on the polarizing plate 11 is adopted, the moisture content of the polarizing plate 11 is set to a higher moisture content within the above range, depending on the heating and drying conditions. It is preferable.

  Further, the pressure-sensitive adhesive layer 12 is aged by storing for a certain period (usually about 10 days after the application of the pressure-sensitive adhesive composition). During this storage, the moisture content of the polarizing plate with adhesive 21 varies, but in the present invention, since the polarizing plate 11 whose moisture content is controlled in advance within the above range is used, curling occurs. Can be suppressed as much as possible. The moisture content of the polarizing plate 11 and the polarizing plate 21 with the adhesive is such that the polarizing plate 11 and the polarizing plate 21 with the adhesive 21 are in a range of 23 ± 10 ° C. and 40 to 65% RH with little variation due to the environment. The purpose is to adjust to saturated moisture content. Therefore, the polarizing plate with the pressure-sensitive adhesive can be prepared by using the same method as the method for adjusting the water content of the polarizing plate 11 even in the process of manufacturing the polarizing plate 21 with the pressure-sensitive adhesive from the polarizing plate 11 whose water content has been adjusted. You may adjust so that the moisture content of 21 may become in the said range.

  Bonding of the polarizing plate 21 with the adhesive and the protective film 22 is performed using the surface on which the adhesive layer 12 or the like is not laminated as the bonding surface, thereby producing the polarizing plate 31 with the protective film.

  Moreover, it does not specifically limit as a method of laminating | stacking an optical function layer on the polarizing plate 31 with a protective film, and can produce by a conventionally well-known method according to the kind of optical function layer.

  Furthermore, when producing an image display apparatus using the polarizing plate 31 with a protective film which concerns on this invention, or an optical film, it can carry out by a conventionally well-known method. For example, when applying the polarizing plate 31 with a protective film to a liquid crystal display device, the following method is used. That is, first, the separator 13 is peeled off, and the liquid crystal cell and the polarizing plate 31 with a protective film are bonded to each other with the pressure-sensitive adhesive layer 12 as an adhesive surface to produce a liquid crystal display element. Furthermore, a component such as an illumination system is formed on the liquid crystal display element as necessary, and a liquid crystal display device is manufactured by incorporating a drive circuit or the like.

  In addition, the optical film which laminated | stacked the said optical function layer on the polarizing plate 31 with a protective film is also producible also by the system laminated | stacked separately sequentially in the manufacture processes, such as a liquid crystal display device. However, an optical film laminated in advance is excellent in quality stability, assembly work, and the like, and has an advantage that productivity of an image display device and the like can be improved. For the lamination, an appropriate adhesive means such as an adhesive layer can be used. When adhering the polarizing plate 31 with the protective film and other optical films, their optical axes can be arranged at an appropriate angle in accordance with the target retardation characteristics.

  In the above aspect, the polarizing plate 31 with a protective film according to the present invention can be used as a transmission type.

  The polarizing plate 31 with a protective film according to the present invention can also be used as an optical film (not shown) in which other optical functional layers are laminated depending on the application.

  The optical functional layer is not particularly limited. For example, when the separator 13 in the polarizing plate 31 with the protective film is peeled off and the optical functional layer is adhered to the pressure-sensitive adhesive layer 12, a retardation film (1/2 or 1/4 wavelength film or the like) is used. Etc.). These films can use one layer or two or more layers as required. For example, a retardation film can be laminated on the polarizing plate 31 with a protective film of the present invention and used as an elliptically polarizing plate or a circularly polarizing plate.

  Moreover, when using a viewing angle expansion film as an optical function layer, the polarizing plate of a wide viewing angle is obtained by laminating | stacking between the polarizer 1 and the adhesive layer 12, for example.

  The reflective polarizing plate is a polarizing plate with a protective film 31 provided with a reflective layer, and is applied to a reflective liquid crystal display device that reflects and displays incident light from the viewing side (display side). The reflective polarizing plate can be formed by an appropriate method such as attaching a reflective layer made of metal or the like to the protective layer 2 on the side opposite to the side on which the birefringent layer is laminated. For example, one having a foil or a vapor deposition film made of a reflective metal such as aluminum is provided on one surface of the protective film 22 or the like matted as necessary. Moreover, what attached the metal reflective layer by appropriate methods, such as a vapor deposition system and a plating system, on the surface fine concavo-convex structure by the fine particle containing of the said protective layer 2 etc. are mentioned. The reflective layer having the fine concavo-convex structure has the advantage that incident light can be diffused by irregular reflection to prevent reflection and irregular reflection, and to suppress uneven brightness. Further, the fine particle-containing protective layer 2 has an advantage that incident light and its reflected light are diffused when passing through it and light and dark unevenness can be further suppressed. The reflective layer having a fine concavo-convex structure reflecting the surface fine concavo-convex structure of the protective layer 2 is formed by protecting the metal by an appropriate method such as a vapor deposition method such as a vacuum vapor deposition method, an ion plating method, a sputtering method, or a plating method. It can be performed by a method of directly attaching to the surface of the layer 2 or the like.

  In addition, the reflective polarizing plate can be used as a reflective sheet in which a reflective layer is provided on an appropriate film in accordance with the protective layer 2 instead of directly forming the protective polarizing plate 31 with the protective film on the protective layer 2. It can also be used. Since the reflective layer is usually made of metal, the usage pattern in which the reflective surface is covered with the protective layer 2 or a polarizing plate prevents the reflectance from being lowered due to oxidation. Furthermore, it is possible to maintain the initial reflectance over a long period of time and to separately stack the protective layer 2 on the reflective layer.

  The transflective polarizing plate can be obtained by using a transflective reflective layer such as a half mirror that reflects and transmits light with the reflective layer. The transflective polarizing plate is usually provided on the back side of the liquid crystal cell. When a transflective liquid crystal display device equipped with such a transflective polarizing plate is used in a bright environment, external light incident from the viewing side (display surface side) is used as display light and used in a dark environment. In that case, light from a backlight or the like is used as display light. Therefore, power consumption can be reduced.

  An elliptically polarizing plate or a circularly polarizing plate in which a retardation film is further laminated on the polarizing plate 31 with a protective film will be described. As a method of laminating the retardation film on the polarizing plate 31 with the protective film, after the separator 13 is peeled off, it is laminated via the pressure-sensitive adhesive layer 12 or a new adhesive layer is formed on the surface from which the protective film 22 is peeled off. For example, a method in which the protective film 22 is not peeled off, the adhesive layer is provided or the adhesive layer is provided without being provided, and the like is appropriately used. A retardation film or the like is used when changing linearly polarized light into elliptically polarized light or circularly polarized light, changing elliptically polarized light or circularly polarized light into linearly polarized light, or changing the polarization direction of linearly polarized light. In particular, a so-called ¼ wavelength film (also referred to as a λ / 4 plate) is used as a retardation film that changes linearly polarized light into circularly polarized light or changes circularly polarized light into linearly polarized light. A half-wave film (also referred to as a λ / 2 plate) is usually used when changing the polarization direction of linearly polarized light.

  The elliptically polarizing plate compensates (prevents) coloring (blue or yellow) caused by birefringence of the liquid crystal layer of a liquid crystal display device of STN (Super Twisted Nematic) mode, for example, when displaying monochrome without the coloring. Used effectively. Further, the one in which the three-dimensional refractive index is controlled is preferable because it can compensate (prevent) coloring that occurs when the screen of the liquid crystal display device is viewed from an oblique direction. The circularly polarizing plate is effectively used, for example, when adjusting the color tone of an image of a reflective liquid crystal display device in which an image is displayed in color, and also has an antireflection function. Specific examples of the retardation film include a birefringent film obtained by stretching a film made of an appropriate polymer such as polycarbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polypropylene, other polyolefins, polyarylate, and polyamide. And an alignment film of a liquid crystal polymer, and a liquid crystal polymer alignment layer supported by a film. The retardation film may have an appropriate retardation according to the purpose of use, such as those for the purpose of compensating for coloration, viewing angle, etc. due to birefringence of various wavelength films and liquid crystal layers, for example. What laminated | stacked retardation film and controlled optical characteristics, such as retardation, may be used.

  The elliptically polarizing plate and the reflective elliptical polarizing plate are obtained by laminating a protective film-attached polarizing plate 31 or a reflective polarizing plate and a retardation film in an appropriate combination. Such an elliptically polarizing plate or the like can also be formed by sequentially laminating them sequentially in the manufacturing process of the liquid crystal display device so as to be a combination of a (reflection type) polarizing plate and a retardation film. An optical film such as a polarizing plate has an advantage that it can improve the production efficiency of a liquid crystal display device and the like because of excellent quality stability and lamination workability.

  A polarizing plate obtained by bonding a polarizing plate 31 with a protective film and a brightness enhancement film is usually provided on the back side of the liquid crystal cell. The brightness enhancement film reflects a linearly polarized light with a predetermined polarization axis or a circularly polarized light in a predetermined direction when natural light is incident due to a backlight such as a liquid crystal display device or reflection from the back side, and transmits other light. The polarizing plate in which the brightness enhancement film is laminated with the polarizing plate 31 with the protective film allows light from a light source such as a backlight to enter to obtain transmitted light in a predetermined polarization state and transmit light other than the predetermined polarization state. Without being reflected. The light reflected on the surface of the brightness enhancement film is further inverted through a reflective layer provided on the rear side thereof and re-incident on the brightness enhancement film, and a part or all of the light is transmitted as light in a predetermined polarization state. Luminance can be improved by increasing the amount of light transmitted through the improvement film and increasing the amount of light that can be used for liquid crystal image display or the like by supplying polarized light that is difficult to absorb to the polarizer 1. For example, when light is incident through the polarizer 1 from the back side of the liquid crystal cell by using a backlight or the like without using a brightness enhancement film, light having a polarization direction that does not coincide with the polarization axis of the polarizer 1 is It is almost absorbed by the polarizer 1 and does not pass through the polarizer 1. Specifically, although depending on the characteristics of the polarizer 1 used, approximately 50% of the light is absorbed by the polarizer 1, and the amount of light that can be used for liquid crystal image display or the like is reduced accordingly. Becomes darker. The brightness enhancement film allows light having a polarization direction that is absorbed by the polarizer 1 to be reflected once by the brightness enhancement film without being incident on the polarizer 1, and further through a reflection layer or the like provided on the rear side thereof. Inverting and re-entering the brightness enhancement film is repeated, and only the polarized light whose polarization direction is such that the polarization direction of the light reflected and inverted between the two passes through the polarizer 1 is obtained. Is transmitted and supplied to the polarizer 1. Thereby, light, such as a backlight, can be efficiently used for image display of the liquid crystal display device, and the display screen can be brightened.

  A diffusion plate may be provided between the brightness enhancement film and the reflection layer. The light in the polarization state reflected by the brightness enhancement film travels to the reflection layer or the like, but the installed diffusion plate uniformly diffuses the light passing therethrough and simultaneously cancels the polarization state and becomes a non-polarization state. That is, the diffuser plate returns the polarized light to the original natural light state. The light in the non-polarized state, that is, the natural light state is directed to the reflection layer and the like, reflected through the reflection layer and the like, and again passes through the diffusion plate and reenters the brightness enhancement film. In this way, by providing a diffuser plate that returns polarized light to the original natural light state between the brightness enhancement film and the reflective layer, etc., while maintaining the brightness of the display screen, the display screen display unevenness is reduced and uniform. Can provide a bright screen. By providing such a diffuser plate, it is considered that the first incident light has a moderate increase in the number of repetitions of reflection, and in combination with the diffusion function of the diffuser plate, a uniform bright display screen can be provided.

  The brightness enhancement film has a characteristic of transmitting linearly polarized light with a predetermined polarization axis and reflecting other light, such as a multilayered thin film of dielectric material or a multilayered laminate of thin film films having different refractive index anisotropy. Such as those having a cholesteric liquid crystal polymer alignment film or its alignment liquid crystal layer supported on a film substrate, reflecting either left-handed or right-handed circularly polarized light and transmitting other light Appropriate things such as can be used.

  Therefore, in the above-described brightness enhancement film that transmits linearly polarized light having the predetermined polarization axis, the transmitted light is directly incident on the polarizing plate 31 with the protective film so as to be absorbed by the polarizing plate 31 with the protective film. It is possible to transmit efficiently while suppressing loss. On the other hand, a brightness enhancement film of a type that emits circularly polarized light, such as a cholesteric liquid crystal layer, can be incident on the polarizer 1 as it is. Furthermore, when it is desired to suppress absorption loss, it is preferable that the circularly polarized light is linearly polarized through a retardation plate and incident on the polarizing plate 31 with a protective film. Note that circularly polarized light can be converted to linearly polarized light by using a quarter wave plate as the retardation plate.

  A retardation film that functions as a ¼ wavelength film in a wide wavelength range such as a visible light region shows, for example, a retardation layer that functions as a ¼ wavelength film for light-colored light having a wavelength of 550 nm and other retardation characteristics. It can be obtained by a method of superposing a retardation layer, for example, a retardation layer functioning as a ½ wavelength film.

  In addition, the cholesteric liquid crystal layer can also be obtained by reflecting circularly polarized light in a wide wavelength range such as the visible light region by combining two or more layers with different reflection wavelengths and having an overlapping structure. Can do. As a result, transmitted circularly polarized light in a wide wavelength range can be obtained.

  Moreover, the polarizing plate 31 with a protective film may consist of what laminated | stacked the polarizing plate 31 with a protective film, and the optical function layer of 2 layers or 3 layers or more like the said polarization splitting-type polarizing plate. Therefore, a reflective elliptical polarizing plate or a semi-transmissive elliptical polarizing plate in which the above-mentioned reflective polarizing plate or transflective polarizing plate and a retardation film are combined may be used.

  The polarizing plate 31 with a protective film and an optical film including the same according to the present invention can be applied to various image display devices such as a liquid crystal display device and an electroluminescence (EL) display device.

  For example, when applied to a transmissive liquid crystal display device, the liquid crystal display device is configured by providing a liquid crystal cell between a pair of transmissive polarizing plates (or optical films). The transmissive polarizing plate and the liquid crystal cell are bonded with a conventionally known pressure-sensitive adhesive or the like. The front polarizing plate on the display surface side and the rear polarizing plate on the back surface side of the liquid crystal cell may be the same type or different types. When manufacturing a liquid crystal display device, for example, a single layer or an appropriate part such as a diffuser plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffuser plate, or a backlight is placed in an appropriate position. Two or more layers can be arranged.

  As a display mode of the liquid crystal display device, a TN (Twisted Nematic) mode, an STN mode, a VA (Vertical Aligned) mode, or an OCB (Optically self-compensated birefringence) mode can be applied.

  Moreover, the polarizing plate 31 with a protective film of this invention or an optical film is applicable also to an organic electroluminescence display. In general, in an organic EL display device, a transparent electrode, an organic light emitting layer, and a metal electrode are sequentially laminated on a transparent substrate to form a light emitter (organic EL light emitter). Here, the organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative and the like and a light emitting layer made of a fluorescent organic solid such as anthracene, Or, a structure having various combinations such as a laminate of an electron injection layer composed of such a light emitting layer and a perylene derivative, or a laminate of these hole injection layer, light emitting layer, and electron injection layer is known. ing.

  In organic EL display devices, holes and electrons are injected into the organic light-emitting layer by applying a voltage to the transparent electrode and the metal electrode, and the energy generated by recombination of these holes and electrons excites the fluorescent material. Then, light is emitted on the principle that the excited fluorescent material emits light when returning to the ground state. The mechanism of recombination in the middle is the same as that of a general diode, and as can be predicted from this, the current and the emission intensity show strong nonlinearity with rectification with respect to the applied voltage.

  In the organic EL display device, it is sufficient that at least one of the electrodes has transparency in order to extract light emitted from the organic light emitting layer. Usually, a transparent electrode formed of indium tin oxide (ITO) or the like is used as the anode. On the other hand, in order to facilitate electron injection and increase luminous efficiency, it is important to use a material having a small work function for the cathode, and usually metal electrodes such as Mg—Ag and Al—Li are used.

  In the organic EL display device having such a configuration, the organic light emitting layer is formed of a very thin film having a thickness of about 10 nm. For this reason, the organic light emitting layer transmits light almost completely like the transparent electrode. As a result, light that is incident from the surface of the transparent substrate at the time of non-light emission, passes through the transparent electrode and the organic light emitting layer, and is reflected by the metal electrode is again emitted to the surface side of the transparent substrate. The display surface of the organic EL display device looks like a mirror surface.

  In an organic EL display device comprising an organic electroluminescent light emitting device comprising a transparent electrode on the surface side of an organic light emitting layer that emits light upon application of a voltage and a metal electrode on the back side of the organic light emitting layer, the surface of the transparent electrode While providing the polarizing plate 31 with a protective film in the side, a retardation film can be provided between these transparent electrodes and the polarizing plate 31 with a protective film.

  Since the retardation film and the polarizing plate 31 with the protective film have a function of polarizing light incident from the outside and reflected by the metal electrode, there is an effect that the mirror surface of the metal electrode is not visually recognized by the polarization action. In particular, if the retardation film is composed of a ¼ wavelength film and the angle formed by the polarization direction of the polarizing film 31 with the protective film and the retardation film is adjusted to π / 4, the mirror surface of the metal electrode is completely shielded. can do.

  That is, external light incident on the organic EL display device is transmitted only by the linearly polarized light component by the polarizing plate 31 with the protective film. This linearly polarized light is generally elliptically polarized light by the retardation film. In particular, when the retardation film is a ¼ wavelength film and the angle formed by the polarization direction of the polarizing film 31 with the protective film and the retardation film is π / 4, it becomes circularly polarized light.

  This circularly polarized light is transmitted through the transparent substrate, the transparent electrode, and the organic thin film, is reflected by the metal electrode, is again transmitted through the organic thin film, the transparent electrode, and the transparent substrate, and becomes linearly polarized light again on the retardation film. And since this linearly polarized light is orthogonal to the polarization direction of the polarizing plate 31 with a protective film, it cannot permeate | transmit the polarizing plate 31 with a protective film. As a result, the mirror surface of the metal electrode can be completely shielded.

EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, this invention is not limited to a following example, unless the summary is exceeded.
(Example 1)
(Production of polarizer)
The PVA film was stretched 3 times in 30 ° C. iodine and KI aqueous solution and then stretched in boric acid and KI aqueous solution at 55 ° C. to a total stretching ratio of 6 times to obtain a polarizer having a thickness of 25 μm.

(Preparation of polarizing plate)
A TAC film having a thickness of 40 μm was bonded to both surfaces of the polarizer using a PVA adhesive and dried at 80 ° C. for 5 minutes to prepare a polarizing plate.

  Next, the moisture content was adjusted by storing the polarizing plate in an environment of temperature 23 ± 5 ° C. × humidity 40% RH for 10 days. Thereafter, the moisture content of the polarizing plate was measured. The method for measuring the moisture content is as described later.

(Preparation of polarizing plate with adhesive)
A pressure-sensitive adhesive layer having a thickness of 22 μm made of an acrylic pressure-sensitive adhesive is formed on one side of a 38 μm-thick separator (MRF-38 manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.), and the polarizing plate and A polarizing plate with an adhesive was prepared by pasting together.

  After measuring the moisture content and curl amount of the pressure-sensitive adhesive-attached polarizing plate and storing it using a rack (shelf) for 10 days in an environment of 23 ± 5 ° C. × 55% RH for the purpose of aging the pressure-sensitive adhesive The curl amount was measured again.

(Preparation of polarizing plate with protective film)
Next, a protective film with a protective film was prepared by pasting a protective film with a thickness of 60 μm (manufactured by Fujimori Kogyo Co., Ltd .: ZN-6) on the polarizing plate with an adhesive. Furthermore, the curl amount of the polarizing plate with a protective film was measured. Subsequently, the separator was peeled off from the polarizing plate with the protective film, and the curl amount was also measured on the peeled polarizing plate. The measurement results are shown in Table 1 below. The method for measuring the curl amount is as described later.
(Example 2)
In the production of the polarizing plate of Example 1, this embodiment was carried out in the same manner as in Example 1 except that the moisture content was adjusted by storing for 3 days in an environment of temperature 23 ± 5 ° C. × humidity 55% RH. A polarizing plate with a protective film according to Example 2 was produced. Further, the moisture content and curl amount were measured in the same manner as in Example 1.
(Example 3)
In the production of the polarizing plate of Example 1, the present embodiment was carried out in the same manner as in Example 1 except that the moisture content was adjusted by storing for 7 days in an environment of temperature 23 ± 5 ° C. × humidity 55% RH. A polarizing plate with a protective film according to Example 3 was produced. Further, the moisture content and curl amount were measured in the same manner as in Example 1.
Example 4
In the production of the polarizing plate of Example 1, the present embodiment was carried out in the same manner as in Example 1 except that the moisture content was adjusted by storing for 10 days in an environment of temperature 23 ± 5 ° C. × humidity 55% RH. A polarizing plate with a protective film according to Example 4 was produced. Further, the moisture content and curl amount were measured in the same manner as in Example 1.
(Example 5)
In preparation of the polarizing plate of the said Example 1, with a protective film similarly to Example 1 except having adjusted the moisture content by storing for 10 days in the environment of temperature 23 +/- 5 degreeC x humidity 65% RH. A polarizing plate was prepared, and the moisture content and curl amount were measured.
(Example 6)
In preparation of the polarizing plate of the said Example 1, it replaced with drying for 5 minutes at 80 degreeC, without storing in adjustment environment, except having adjusted the moisture content by drying for 5 minutes at 75 degreeC. Then, a polarizing plate with a protective film according to Example 6 was produced in the same manner as Example 1. Further, the moisture content and curl amount were measured in the same manner as in Example 1.
(Example 7)
In the production of the polarizing plate of Example 1, Example 7 was carried out in the same manner as Example 1 except that the moisture content was adjusted by immersing in a 20 ° C. water bath for 25 seconds before laminating the pressure-sensitive adhesive layer. The polarizing plate with a protective film concerning this was produced. Further, the moisture content and curl amount were measured in the same manner as in Example 1.
(Example 8)
In the production of the polarizing plate of Example 1, 80 μm TAC films were bonded to both sides of the polarizer, and in the production of the polarizing plate with an adhesive, in an environment of temperature 23 ± 5 ° C. × humidity 55% RH. A polarizing plate with a protective film according to Example 8 was produced in the same manner as Example 1 except that the moisture content was adjusted by storing for 10 days. Further, the moisture content and curl amount were measured in the same manner as in Example 1.
(Comparative Example 1)
In the production of the polarizing plate of Example 1, a protective film was provided in the same manner as in Example 1 except that it was stored for 10 days in an environment of temperature 23 ± 5 ° C. × humidity 30% RH and the moisture content was adjusted. A polarizing plate was produced. Further, the moisture content and curl amount were measured in the same manner as in Example 1.
(Comparative Example 2)
In the production of the polarizing plate of Example 1, a protective film was provided in the same manner as in Example 1 except that it was stored for 10 days in an environment of temperature 23 ± 5 ° C. × humidity 75% RH and the moisture content was adjusted. A polarizing plate was produced. Further, the moisture content and curl amount were measured in the same manner as in Example 1.
(Comparative Example 3)
In the production of the polarizing plate of Example 1, Example 1 and Example 2 were stored except that the moisture content was not adjusted in the conventional process and stored in an environment of temperature 23 ± 5 ° C. × humidity 55% RH for 2 days. Similarly, a polarizing plate with a protective film was produced. Further, the moisture content and curl amount were measured in the same manner as in Example 1.

(Method of measuring moisture content)
The produced pressure-sensitive adhesive-attached polarizing plate was cut into a size of 100 × 100 mm so that the axis angle of the absorption axis of the polarizing plate was 45 degrees to obtain a sample for measuring moisture content. Furthermore, the initial weight of this sample was measured. Subsequently, this sample was dried at 120 ° C. for 2 hours, the dry weight was measured, and the moisture content was measured by the following formula. The weight was measured three times, and the average value was used.

（カール量の測定方法）
粘着剤付き偏光板、保護フィルム付き偏光板及びセパレータ剥離偏光板のそれぞれについて、偏光板の吸収軸の軸角度が４５度となる様に１５インチサイズに切り出して、カール量測定用のサンプルを得た。これらのサンプルをカールが常に図４（ｂ）の様になるように平面台に置いた状態で各々の最大カール量（ｈ_２）を測定した。サンプルは、セパレータ（または粘着剤層）側を上にしたときに凸状にカールしているときは（＋）カール、凹状にカールしているときは（−）カールとした。

(Measurement method of curl amount)
About each of a polarizing plate with an adhesive, a polarizing plate with a protective film, and a separator-peeling polarizing plate, a sample for curling amount measurement is obtained by cutting into a 15 inch size so that the axis angle of the absorption axis of the polarizing plate is 45 degrees. It was. The maximum curl amount (h ₂ ) of each sample was measured in a state where the curl was always placed on a flat table so that the curl was as shown in FIG. When the sample curled convexly when the separator (or pressure-sensitive adhesive layer) side was up, the sample was (+) curled. When the sample was curled concavely, (-) curled was used.

(Evaluation of curl)
The evaluation of the curl amount measurement result was as follows. That is, regarding the polarizing plate with the adhesive after storage in a rack, the case where the (+) curl was 15 mm or more or the (−) curl was 30 mm or more was regarded as defective (×) from the viewpoint of productivity. About the polarizing plate with a protective film, the case where (+) curl was 20 mm or more or (-) curl was 5 mm or more was regarded as defective. About the polarizing plate after separator peeling, the case where (+) curl was 35 mm or more, or (-) curl was 5 mm or more was set as defective (x). When it did not correspond to any case, it was set as favorable ((circle)).

  As described above, the difference in the curl evaluation value between the respective configurations is mainly due to consideration of the bonding efficiency in bonding with other members forming the image display device. For example, when a protective film is bonded to a polarizing plate with an adhesive, if the polarizing plate with an adhesive is a (−) curl, the protective film and the central portion are bonded together, and then bonded together without problems by pressing the end portion. However, if it is a (+) curl, the end part sticks first, so that wrinkles, floats, air entrapment, etc. are likely to cause problems. Therefore, the amount of curl that can be tolerated by (−) curl increases. On the other hand, the polarizing plate after peeling the separator is assumed to be bonded to another member constituting the image display device using the pressure-sensitive adhesive layer after peeling the separator, so that it is opposite to the polarizing plate with pressure-sensitive adhesive. However, for the same reason, the (−) curl tends to cause the above-mentioned problems. About the polarizing plate with a protective film before separator peeling, the curling after separator peeling was considered and evaluated.

(result)
As apparent from Table 1 below, in Examples 1 to 8, by adjusting the moisture content so that the moisture content of the polarizing plate is within a predetermined range, before and after rack storage. All of the polarizing plate with adhesive, the polarizing plate with protective film, and the polarizing plate after separation of the separator were able to suppress the curl amount to a minimum from the viewpoint of productivity.

It is sectional drawing which shows schematic structure of the polarizing plate which concerns on one Embodiment of this invention. It is sectional drawing which shows schematic structure of the polarizing plate with an adhesive which concerns on the said embodiment. It is sectional drawing which shows schematic structure of the polarizing plate with a protective film which concerns on the said embodiment. It is the model which shows the measuring method of the curl amount roughly, Comprising: The figure (a) shows the case where it curls convexly, The figure (b) shows the case where it curls concavely.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Polarizer 2 Protective layer 11 Polarizing plate 12 Adhesive layer 13 Separator 21 Polarizing plate with adhesive 22 Protective film 31 Polarizing plate with protective film

Claims (16)

With a protective film provided with a protective film on the other side and the side of the polarizing plate with the pressure-sensitive adhesive layer and separator of the polarizing plate with the pressure-sensitive adhesive layered on one side of the polarizing plate A polarizing plate,
In the polarizing plate, the moisture content before lamination of the pressure-sensitive adhesive layer and the separator is 2.85 wt% to 3.8 wt%, and the moisture content of the polarizing plate with the pressure-sensitive adhesive is 2 wt% to 2.7 wt%. A polarizing plate with a protective film.   The polarizing plate with a protective film according to claim 1, wherein the polarizing plate includes a polarizer and a protective layer having a thickness of 100 μm or less on at least one surface of the polarizer.   The said protective layer consists of a triacetyl cellulose film, The polarizing plate with a protective film of Claim 2 characterized by the above-mentioned.   An optical film comprising the polarizing plate with a protective film according to claim 1 or the polarizing plate with a protective film after the separator is peeled off, and an optical functional layer.   It has the polarizing plate with a protective film of any one of Claims 1-3, or the polarizing plate with a protective film after the said separator peeling, or the optical film of Claim 4, and a liquid crystal cell, It is characterized by the above-mentioned. Liquid crystal display element.   The polarizing plate with a protective film according to any one of claims 1 to 3, or the polarizing plate with a protective film after separation of the separator, the optical film according to claim 4, or the liquid crystal display element according to claim 5. An image display device provided. A method for producing a polarizing plate with an adhesive in which an adhesive layer and a separator are laminated on one surface of a polarizing plate,
Adjusting the moisture content of the polarizing plate to 2.85 wt% to 3.8 wt%;
With a pressure-sensitive adhesive comprising a step of laminating a pressure-sensitive adhesive layer and a separator on one surface of the polarizing plate to produce a pressure-sensitive adhesive-coated polarizing plate having a moisture content of 2 wt% to 2.7 wt%. Manufacturing method of polarizing plate.   The step of adjusting the moisture content of the polarizing plate is performed under a condition of leaving for 72 hours or more in an environment of a temperature of 23 ± 5 ° C and a humidity of 40 to 65% RH. Manufacturing method of polarizing plate.   The method for producing a polarizing plate with an adhesive according to claim 7, wherein the step of adjusting the moisture content of the polarizing plate is performed by immersing the polarizing plate in water. A method for producing a polarizing plate with a protective film, in which a protective film is provided on the other side of the polarizing plate with the pressure-sensitive adhesive, which is formed by laminating a pressure-sensitive adhesive layer and a separator on one side of the polarizing plate,
Adjusting the moisture content of the polarizing plate to 2.85 wt% to 3.8 wt%;
A step of laminating an adhesive layer and a separator on one surface of the polarizing plate to produce a polarizing plate with an adhesive having a moisture content of 2 wt% to 2.7 wt%;
A method for producing a polarizing plate with a protective film, comprising: attaching a protective film to the other surface of the polarizing plate.   The process for adjusting the moisture content of the polarizing plate is carried out under conditions of standing for 72 hours or more in an environment of a temperature of 23 ± 5 ° C and a humidity of 40 to 65% RH. Manufacturing method of polarizing plate.   The method for producing a polarizing plate with a protective film according to claim 10, wherein the step of adjusting the moisture content of the polarizing plate is performed by immersing the polarizing plate in water.   The polarizing plate with an adhesive obtained by the manufacturing method of the polarizing plate with an adhesive of any one of Claims 7-9.   The polarizing plate with a protective film obtained by the manufacturing method of the polarizing plate with a protective film of any one of Claims 10-12.   An optical film comprising the polarizing plate with an adhesive according to claim 13 or the polarizing plate with a protective film according to claim 14 and an optical functional layer. The image display apparatus provided with the polarizing plate with an adhesive of Claim 13, the polarizing plate with a protective film of Claim 14, or the optical film of Claim 15.

Images