JP2009251213A - Method of manufacturing polarizing plate roll - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method capable of restraining a curl without increasing process steps, when manufacturing in a rolled manner an asymmetric polarizing plate bonded with a polarizer protection layer only on one face of a polarizer. <P>SOLUTION: A polarizing plate is bonded with the polarizer protection layer 2 on one face of the polyvinyl alcohol polarizer 1, is provided directly with a pressure-sensitive adhesive layer 7 comprising a single or plurality of layers, on the other face of the polarizer 1, is bonded with a separation film 9 on a surface of the outermost pressure-sensitive adhesive layer 8, and is bonded with a separable protective film 6 on a surface of the polarizer protection layer 2. The protective film 6 has shearing adhesive force of ≤80 N/625 mm<SP>2</SP>to the polarizer protection layer 2, and the polarizing plate roll is rolled to bring the protective film 6 into an inside thereof, when manufacturing the polarizing plate roll by rolling the polarizing plate roll-likely. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  In the present invention, a polarizer protective layer is bonded to one side of a polarizer made of a polyvinyl alcohol-based resin, an adhesive layer is directly provided on the other side of the polarizer, and an adhesive provided on the other side of the polarizer. The agent layer is a single layer or a plurality of layers, a separate film is bonded to the outermost pressure-sensitive adhesive layer surface, and a peelable protective film is bonded to the surface of the polarizer protective layer Is rolled up into a roll shape to produce a polarizing plate roll. More specifically, the present invention relates to a method for manufacturing a polarizing plate with curling suppressed in a roll shape.

  In a liquid crystal display device, a polarizing plate is used as a component for extracting linearly polarized light from light emitted from a light source and making it incident on a liquid crystal cell and detecting linearly polarized light emitted from the liquid crystal cell. A polarizing plate is usually constituted by laminating a polarizer protective layer on at least one surface of a polarizer made of a polyvinyl alcohol resin to which a dichroic dye is adsorbed and oriented. In addition, an adhesive layer is provided on one side of the polarizing plate for bonding to a liquid crystal cell or other optical member, and the surface is covered with a separate film to protect it until use. It is distributed in a configuration in which a peelable protective film having an agent layer is provided. Furthermore, generally a polarizing plate is manufactured in the state wound by the elongate roll shape.

  In this specification, the protective film is bonded to the surface of the polarizer protective layer on one side in this way, and the separate film is bonded to the surface of the pressure-sensitive adhesive layer on the other side, which is manufactured in a rolled state. The polarizing plate is referred to as a “polarizing plate roll”, and a product cut from the polarizing plate to a predetermined size is referred to as a “polarizing plate product”. The term “polarizing plate” is a polarizer made of a polyvinyl alcohol resin as an essential element, and a polarizer protective layer made of a transparent resin film is laminated on at least one surface thereof, and a liquid crystal cell or other surface is laminated on one surface. It refers to a state in which a pressure-sensitive adhesive layer for bonding to an optical member is provided, and in some cases, it may be used to include a polarizing plate roll or a polarizing plate product as described above.

  About the above polarizing plates, it is known that a phenomenon of warping toward one surface, that is, curling is likely to occur. In particular, as shown in JP-A-10-186133 (Patent Document 1), a polarizer protective layer made of a transparent resin is provided on one side of a polyvinyl alcohol-based polarizer film, and a pressure-sensitive adhesive layer is provided directly on the other side. Recently, thinned polarizing plates are being adopted recently, and it is known that curling is more likely to occur in such a configuration in which the polarizer protective layer on one side of the polarizer film is omitted. In view of suitability for bonding to a liquid crystal cell, a polarizing plate with little curling or a constant curling direction is desired.

  When the layers constituting the polarizing plate are bonded together, curling is likely to occur due to stress generated particularly when the protective film is bonded. In order to suppress or correct curl, a method of performing a special surface treatment on the constituent layer of the polarizing plate, a method of providing a layer having an anti-curling function on the polarizing plate, and the like are known. For example, in JP-A-2006-251224 (Patent Document 2), when a polarizing plate is produced by applying a protective film made of a transparent resin on both sides of a polarizer, one protective film is subjected to curl correction treatment. Then, after the polarizer and the protective film are bonded together, or after the polarizer and the protective film are bonded together, the surface of one of the protective films is subjected to curl correction treatment, or both of the protective films have different treatment strengths. After applying the correction treatment, the polarizer and the protective film are bonded together, or after the polarizer and the protective film are bonded together, the surfaces of both protective films are subjected to curl correction processing with different processing strengths. Is disclosed. Here, as the curl correction treatment, specifically, a method of applying water vapor or solvent vapor to the surface of the protective film that does not contact the polarizer, a method of applying a solvent to the surface of the protective film that does not contact the polarizer, and a protective film The method of apply | coating a polymer solution to the surface which does not contact a polarizer is illustrated. In the method disclosed in Patent Document 2, a process for performing curl correction processing is required, and the manufacturing cost is increased accordingly.

  JP-A-2005-338367 (Patent Document 3) uses a protective film and a separate film having a strong shear adhesive force to the polarizing plate, and adjusts the ratio of the shear adhesive force of the protective film and the separate film to the polarizing plate. A method for suppressing curling is disclosed. The method disclosed in Patent Document 3 is effective for a polarizing plate in which a polarizer protective layer is bonded to both sides of a polarizer, but an asymmetrical structure in which a polarizer protective layer is bonded to only one side of a polarizer. The effect of the polarizing plate is small. Further, in the method disclosed in Patent Document 3, curling of the polarizing plate is suppressed by the balance of the strong shearing adhesive force between the protective film and the separating film. Therefore, if the separating film is peeled off before being attached to the liquid crystal cell, the polarizing plate Curling is likely to occur.

Japanese Patent Laid-Open No. 10-186133 JP 2006-251224 A JP 2005-338367 A

  Then, the objective of this invention is the said polarizing plate roll which can suppress a curl, without increasing a process in manufacturing the asymmetrical polarizing plate by which the polarizer protective layer is bonded only to the single side | surface of a polarizer in roll shape. It is in providing the manufacturing method of.

That is, in the present invention, a polarizer protective layer is bonded to one side of a polarizer made of polyvinyl alcohol resin, a pressure-sensitive adhesive layer is directly provided on the other side of the polarizer, and provided on the other side of the polarizer. The pressure-sensitive adhesive layer is one layer or a plurality of layers, a separate film is bonded to the outermost pressure-sensitive adhesive layer surface, and a peelable protective film is bonded to the surface of the polarizer protective layer. A polarizing plate roll is manufactured by winding a polarizing plate, wherein the protective film is composed of a protective film having a shearing adhesive force of 80 N / 625 mm ² or less with respect to the polarizer protective layer. A method for producing a polarizing plate roll, which is wound with the inner side facing up, is provided.

  As one form of the layer structure of the polarizing plate produced by the method of the present invention, a polarizer protective layer is bonded to one side of the polarizer, and a pressure-sensitive adhesive layer is directly provided on the other side of the polarizer. A separate film is bonded to the surface of the layer, and a peelable protective film is bonded to the surface of the polarizer protective layer.

  As another form of the layer structure of the polarizing plate produced by the method of the present invention, a polarizer protective layer is bonded to one side of the polarizer, and a pressure-sensitive adhesive layer is directly provided on the other side of the polarizer. A retardation film, an outer pressure-sensitive adhesive layer, and a separate film are bonded in this order to the surface of the pressure-sensitive adhesive layer, and a peelable protective film is bonded to the surface of the polarizer protective layer. Can also be mentioned.

  According to the present invention, the curling of a product can be suppressed without increasing the number of steps in manufacturing an asymmetric polarizing plate in which a polarizer protective layer is bonded only on one side of the polarizer in a roll shape. . In addition, the curl of the polarizing plate product is prevented from changing greatly even if the separated film is peeled and removed immediately before the product cut into the predetermined size from the polarizing plate roll obtained is bonded to a liquid crystal cell or other optical member. can do.

  Hereinafter, the present invention will be described in detail with appropriate reference to the accompanying drawings. An example of the layer structure of a polarizing plate roll or polarizing plate product produced according to the present invention is shown in FIG. 1, and another example of the layer structure is shown in FIG.

  In the example shown in FIG. 1, a polarizer protective layer 2 made of a transparent resin film is bonded to one side of a polarizer 1, and an adhesive layer 8 is provided on the other side of the polarizer 1. It is configured. Then, a peelable protective film 6 is bonded to the surface of the polarizer protective layer 2, and a separate film 9 is bonded to the surface of the pressure-sensitive adhesive layer 8 to constitute a polarizing plate roll or a polarizing plate product 10. ing.

  On the other hand, in the example shown in FIG. 2, a polarizer protective layer 2 made of a transparent resin film is bonded to one surface of the polarizer 1, and the retardation film 3 is interposed on the other surface of the polarizer 1 via an adhesive layer 7. Is bonded, and the outer pressure-sensitive adhesive layer 8 is further provided on the surface thereof to constitute the polarizing plate 5. Then, a peelable protective film 6 is bonded to the surface of the polarizer protective layer 2, and a separate film 9 is bonded to the surface of the outer pressure-sensitive adhesive layer 8 to constitute a polarizing plate roll or a polarizing plate product 11. Has been.

  Thus, in the present invention, the polarizer protective layer 2 is bonded to one side of the polarizer 1, the adhesive layer 7 or 8 is directly provided on the other side of the polarizer 1, and the other side of the polarizer 1. The pressure-sensitive adhesive layer provided on the surface side is one layer or a plurality of layers, and a separate film 9 is bonded to the surface of the outermost pressure-sensitive adhesive layer 8, and can be peeled off from the surface of the polarizer protective layer 2. The polarizing plate 4 or 5 to which the protective film 6 is bonded is wound up in a roll shape to manufacture the polarizing plate roll 10 or 11. FIG. 1 shows an example in which the pressure-sensitive adhesive layer provided on the other side of the polarizer 1 is one layer, and FIG. 2 shows that the pressure-sensitive adhesive layer provided on the other side of the polarizer 1 has two layers. Although an example was shown, for example, two or more retardation films 3 may be laminated to form a broadband circularly polarizing plate. In that case, the retardation films are also bonded via an adhesive layer. Therefore, the pressure-sensitive adhesive layer has three or more layers. Even in such a case, the separate film 9 is bonded to the surface of the outermost pressure-sensitive adhesive layer 8.

  Here, the polarizer 1 is an optical element having a property of absorbing linearly polarized light having a vibration plane parallel to the optical axis and transmitting linearly polarized light having a vibration plane orthogonal to the optical axis. Specific examples of the polarizer 1 include those made of a polyvinyl alcohol-based resin film that is uniaxially stretched and has a dichroic dye adsorbed and oriented. As the dichroic dye, iodine or a dichroic organic dye is used. The polyvinyl alcohol resin constituting the polarizer 1 is not only polyvinyl alcohol, which is a saponified product of polyvinyl acetate, but also a copolymer of vinyl acetate and other monomers copolymerizable therewith, such as ethylene or unsaturated carboxylic acid. It may be a vinyl alcohol copolymer which is a saponified polymer.

  A polarizing plate 4 shown in FIG. 1 includes a polarizer 1, a polarizer protective layer 2 bonded to one surface of the polarizer 1, and an adhesive layer 8 provided on the other surface of the polarizer 1. Yes. A peelable protect film 6 is bonded to the surface of the polarizer protective layer 2, and a separate film 9 is bonded to the surface of the pressure-sensitive adhesive layer 8 to obtain a polarizing plate roll or a polarizing plate product 10.

  A polarizing plate 5 shown in FIG. 2 includes a polarizer 1, a polarizer protective layer 2 provided on one surface of the polarizer 1, and a retardation film 3 bonded to the other surface of the polarizer 1 via an adhesive layer 7. And an outer pressure-sensitive adhesive layer 8 provided on the surface of the retardation film 3. Also in this case, a peelable protective film 6 is bonded to the surface of the polarizer protective layer 2, and a separate film 9 is bonded to the surface of the outer pressure-sensitive adhesive layer 8, so that a polarizing plate roll or a polarizing plate product is obtained. 11.

  In the above, the polarizer protective layer 2 provided on one surface of the polarizer 1 can be composed of a transparent resin film, specifically, a cellulose resin film such as triacetyl cellulose or diacetyl cellulose, or an acrylic resin. A film, a cyclic olefin resin film, or the like is used. Triacetyl cellulose is particularly preferred. The polarizer 1 and the polarizer protective layer 2 are usually bonded using an adhesive. Examples of the adhesive include a water-based adhesive made of an aqueous solution of a polyvinyl alcohol resin, and a solventless adhesive containing a curable component.

  Moreover, the retardation film 3 shown in FIG. 2 is an optical element having optical anisotropy, for example, polyvinyl alcohol, polycarbonate, polyester, polyarylate, polyimide, polyolefin, polystyrene, polysulfone, polyethersulfone, Stretching a polymer film made of polyvinylidene fluoride / polymethyl methacrylate, liquid crystal polyester, acetyl cellulose, cyclic polyolefin, saponified ethylene-vinyl acetate copolymer, polyvinyl chloride, etc. to about 1.0 to 6 times. The stretched film etc. which are obtained by these are mentioned. The stretching may be uniaxial stretching or biaxial stretching.

  Examples of retardation films include uniaxial retardation films, wide viewing angle retardation films, low photoelasticity retardation films, temperature-compensated retardation films, and coating retardation films. Can be used in the invention. Commercially available products called coated retardation films include “LC film” (a rod-shaped liquid crystal with twisted orientation) and “NH film” (a rod-shaped liquid crystal with tilted orientation) sold by Nippon Oil Corporation. "WV film" (disc-shaped liquid crystal with tilted orientation) sold by Fujifilm Co., Ltd., "VAC film" (fully biaxially oriented retardation film) sold by Sumitomo Chemical Co., Ltd. And "new-VAC film" (biaxially oriented retardation film).

  When laminating the retardation film 3, as shown in FIG. 2, the retardation film 3 is applied to the pressure-sensitive adhesive layer 7 provided on the opposite side of the polarizer protective layer 2 bonded to one side of the polarizer 1. paste. As described above, the retardation film 3 may be composed of a plurality of sheets. In this case, the retardation films are also bonded to each other via the adhesive layer. In the example of FIG. 2, the pressure-sensitive adhesive layer 7 provided on one surface of the polarizer 1 becomes an adhesive for pasting the retardation film 3 in this way. On the other hand, the pressure-sensitive adhesive layer 8 (in the example of FIG. 1, which is provided on one surface of the polarizer 1) in the example of FIGS. It becomes an adhesive for bonding to an optical member. There are acrylic, urethane, and rubber adhesives. Among these, transparent and optically isotropic ones may be selected and used. Among these, an acrylic pressure-sensitive adhesive is preferably used.

  In the polarizing plate roll or polarizing plate product 10 or 11, the protective film 6 outside the polarizer protective layer 2 and the separate film 9 outside the pressure-sensitive adhesive layer 8 are used for inspecting the polarizing plate product 10 or 11, or the polarizing plate product. It is provided for the purpose of protecting the polarizing plate 4 or 5 and the pressure-sensitive adhesive layer 8 when the 10 or 11 is transported or stored. That is, the protect film 6 is provided for the purpose of protecting the surface of the polarizing plate 4 or 5 and is on the side opposite to the surface where the polarizing plate 4 or 5 is bonded to the liquid crystal cell. The protective film 6 is peeled off after the polarizing plate 4 or 5 is bonded to the liquid crystal cell. Further, the separate film 9 is provided thereon for the purpose of covering the pressure-sensitive adhesive layer 8, and the pressure-sensitive adhesive layer 8 has a surface side for bonding the polarizing plate product 10 or 11 to a liquid crystal cell or another optical member. Become. And the separate film 9 provided on it is peeled and removed immediately before bonding to a liquid crystal cell or another optical member.

  The protective film 6 is usually composed of a transparent base resin film provided with an adhesive layer on the surface. Moreover, the separate film 9 is normally comprised with the transparent resin film in which the mold release process was performed, and the mold release process surface is bonded together to the adhesive layer 8. FIG. As the resin film constituting the protect film 6 and the separate film 9, for example, a film made of polyester such as polyethylene terephthalate or polyethylene naphthalate can be used.

  In the present invention, when the polarizing plate on which the protective film 6 and the separate film 9 are bonded is wound up in a roll shape, the protective film 6 is shown in a schematic sectional view in FIG. Is wound so that the inner side is the inner side and the separate film 9 is the outer side.

When the shear adhesive force of the protective film 6 to the polarizer protective layer 2 exceeds 80 N / 625 mm ² , the stress generated when the protective film 6 is bonded to the polarizer protective layer 2 is difficult to be relaxed, and a predetermined dimension from the polarizing plate roll. In some cases, the curled polarizing plate product 10 or 11 may become larger. In particular, when the separate film 9 is peeled and removed immediately before the polarizing plate 4 or 5 is bonded to a liquid crystal cell or another optical member, the curl that has been suppressed to some extent by the separate film 9 may be further increased. .

Further, when the shear adhesive force of the protective film 6 to the polarizer protective layer 2 exceeds 80 N / 625 mm ² , the shear adhesive force is large even when the protective film 6 is placed inside when the polarizing plate is rolled. The curl does not occur in the normal curl direction, and the reverse curl cannot be prevented by the storage over time and the reverse curl generated in the manufacturing process cannot be corrected.

  Here, the normal curl means a state where the side of the separate film 9 is convex, and the reverse curl means a state where the side of the separate film 9 is concave. If the curl is positive, when the separate film 9 is peeled off and bonded to the liquid crystal cell on the pressure-sensitive adhesive layer 8 side, the pressure-sensitive adhesive layer 8 side facing the liquid crystal cell is curled and convex. The pressure-sensitive adhesive layer 8 can be spread on the surface of the liquid crystal cell, and defects such as floating and peeling are unlikely to occur. On the other hand, in the case of reverse curling, when the separate film 9 is peeled off and bonded to the liquid crystal cell on the pressure-sensitive adhesive layer 8 side, the pressure-sensitive adhesive layer 8 side facing the liquid crystal cell is curled and concave. Swelling occurs at the portion, and even when pressed at the time of bonding to the liquid crystal cell, the central portion cannot be sufficiently bonded, and floating defects are likely to occur.

Therefore, in the present invention, the protective film 6 having a shear adhesive strength with respect to the polarizer protective layer 2 of 80 N / 625 mm ² or less is used. Thereby, the stress which arises when bonding the protective film 6 to the polarizer protective layer 2 can be relieved. Further, when the polarizing plate roll is wound, the protective film 6 is set to the inner side to generate a wrinkle in the normal curl direction, preventing reverse curl due to storage over time and the protective film 6 to protect the polarizer protective layer 2. Corrects the reverse curl that is likely to occur when pasting to the surface. There is no particular limitation on the lower limit of the shear adhesive force of the protective film 6 to the polarizer protective layer 2, but it is generally preferable that the positive curl of the polarizing plate product 10 or 11 due to curling does not become strong, for example, the polarizer protective layer It is preferable that the shear adhesive strength with respect to 2 is 20 N / 625 mm ² or more.

  As described above, the protect film 6 is formed by providing a pressure-sensitive adhesive layer on the surface of a transparent resin film. The pressure-sensitive adhesive used for the protective film 6 is configured using a polymer such as acrylic, urethane, or rubber similar to that described above for the pressure-sensitive adhesive layers 7 and 8. Of these, an acrylic pressure-sensitive adhesive is preferably used because of its excellent transparency. Acrylic adhesives are generally based on one or more acrylate esters such as butyl acrylate, ethyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, and polar monomers are copolymerized therewith. Composed of polymer. Examples of polar monomers include (meth) acrylic acid, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, and glycidyl. Mention may be made of monomers having a carboxyl group, a hydroxyl group, an amino group, an epoxy group and the like, such as (meth) acrylate. Moreover, crosslinking agents, such as a polyisocyanate compound, an epoxy compound, and an aziridine compound, are mix | blended with the adhesive.

In order to obtain a protective film having a relatively low shear adhesive force to the polarizer protective layer 2 of 80 N / 625 mm ² or less as defined in the present invention, for example, the base resin film of the protective film is made of an elastic modulus. It is possible to take measures such as constituting with a low material, or constructing the adhesive layer provided on the base resin film with an adhesive having a low storage elastic modulus. Resin films provided with a pressure-sensitive adhesive layer that can serve as a protective film are commercially available from various manufacturers, so select a resin film that satisfies the value specified in the present invention for the shear adhesive strength to the polarizer protective layer 2. Can be used. As such a protective film, for example, “AS3-303” and “AS3-304” sold by Fujimori Kogyo Co., Ltd., “SAT-4238T-JSL” sold by Sanei Kaken Co., Ltd., Examples include “PT-PET814 / S” sold by Tac Kasei Co., Ltd. and “ANO-7 / S” sold by Teijin DuPont Films Ltd. (all trade names). In any of these, an acrylic pressure-sensitive adhesive layer is formed on the surface of a polyethylene terephthalate film.

  Here, the measuring method of the shear adhesive force with respect to the polarizer protective layer 2 of the protective film 6 is demonstrated based on FIG. 4A and 4B are diagrams schematically showing a state in which the shear adhesive force is measured, in which FIG. 4A is a longitudinal sectional view and FIG. 4B is a plan view.

First, as shown in FIG. 1, the polarizer protective layer 2 is bonded to one side of the polarizer 1, and the pressure-sensitive adhesive layer 8 and the separate film 9 are bonded to the other side of the polarizer 1 in this order. The polarizer protective layer 2 is bonded to one side of the polarizer 1 as shown in FIG. 2 or the polarizer 1, and the retardation film 3 is interposed on the other side of the polarizer 1 via the adhesive layer 7. Is prepared, and further, a polarizing plate 5 in which the pressure-sensitive adhesive layer 8 and the separate film 9 are bonded in this order on the surface is prepared (both states in which the protect film 6 is not bonded), and a separate film is prepared. 9 is peeled off, and the pressure-sensitive adhesive layer 8 is bonded to the glass plate 15 and fixed. In addition, what is necessary is just to use for the following measurements, after peeling off the protective film, when the polarizing plate 4 or 5 of the state in which the protective film 6 was bonded is bonded to the glass plate 15. FIG. On the other hand, the protective film 6 to be bonded onto the polarizer protective layer 2 is cut into a rectangle of 100 mm × 25 mm. The protective film 6 cut in this way is bonded on the pressure-sensitive adhesive layer side so that only the bonded portion of 25 mm × 25 mm overlaps the polarizer protective layer 2 of the polarizing plate 4 or 5 for measuring the shear adhesive force. A sample. Then, under an environment of a temperature of 23 ° C. and a relative humidity of 50%, the protective film 6 was pulled to the side not bonded to the polarizer protective layer 2 (in the direction of arrow P) at a pulling speed of 0.25 mm / min. The maximum load is the shear adhesive strength. Since the area where the shearing force is applied is 25 mm × 25 mm = 625 mm ² , the shearing adhesive force is expressed by a load per 625 mm ² (unit: N).

  Next, a method for measuring the curl amount will be described with reference to FIG. FIG. 5 is a perspective view schematically showing a curled amount measurement state of a polarizing plate product cut to a predetermined size from a polarizing plate roll. First, the polarizing plate 21 to which the protective film is bonded is cut into a 90 mm × 50 mm rectangle to obtain a curl measurement sample. Then, the curled sample is placed on a reference surface 25 (for example, a flat surface on a desk) with its convex surface down. In FIG. 5, the surface when it is assumed that there is no curl in the sample is displayed as a virtual surface 23 represented by a square ABCD. One of the four corners in the virtual plane 23 is at position A1 in the curled sample, in position C1 in the sample with another corner C curled, and in the sample with the other corners B and D curled. B1 and B1 are at the same position, B1 and B are the same position, and D1 and D are also displayed at the same position (that is, it corresponds to a state in which B and D do not float in the four corners of the sample) ). In practice, however, three or four of the four corners of the sample may be raised. Thus, the height H from the reference plane is measured for each of the four corners A1, B1, C1, and D1 of the sample. The maximum value of the floating heights of these four corners is determined, and the maximum value is set as the curl amount of the sample.

  Then, the curl amount at which the separation film 9 side in FIG. 1 or FIG. In this case, as described above, when the separate film 9 is peeled off and bonded to the liquid crystal cell on the adhesive layer 8 side, the adhesive layer 8 side facing the liquid crystal cell is curled and convex. The pressure-sensitive adhesive layer 8 can be spread on the surface of the liquid crystal cell by pressing at the time of bonding, and even if the absolute value of the curl amount is somewhat large, defects such as lifting and peeling do not occur. However, even if it is a positive curl, if its absolute value becomes too large, it cannot be completely bonded to the liquid crystal cell up to the end, and the end tends to peel off.

  On the other hand, the curl amount in which the separate film 9 side in FIG. 1 or FIG. In this case, as described above, when the separate film 9 is peeled off and attached to the liquid crystal cell on the adhesive layer 8 side, the adhesive layer 8 side facing the liquid crystal cell is curled and concave. For this reason, a bulge is generated at the central portion of the polarizing plate, and the central portion cannot be sufficiently bonded even when pressed at the time of bonding to the liquid crystal cell, often resulting in a floating defect. However, even if it is reverse curl, if its absolute value is small, it can be sufficiently bonded to the liquid crystal cell by pressing during bonding.

  In order to prevent a problem caused by the curling of the polarizing plate when it is bonded to the liquid crystal cell, the curling amount of the polarizing plate product measured as described above is in the range of −2 mm to +3 mm. Is preferred. The amount of curl varies depending on the size of the polarizing plate or the polarizing plate product. Here, the curl amount is measured by cutting into a 90 mm × 50 mm rectangle. In order to spread the agent layer 8 and make it closely adhere to the liquid crystal cell, it is preferable that the curl amount is in the above range even if the sizes are different.

  EXAMPLES The present invention will be described below with reference to comparative examples as appropriate, but the present invention is not limited to these examples. Here, the polarizing plate having the layer structure shown in FIG. 2 was produced in a roll shape. As the protective film 6, the following commercially available products were used (the names in “” are trade names). In either case, an acrylic pressure-sensitive adhesive layer is formed on the surface of a 38 μm thick polyethylene terephthalate film, and the adhesive strength is adjusted depending on the type of the acrylic pressure-sensitive adhesive.

“AS3-304”: manufactured by Fujimori Industry Co., Ltd. It was 74N / 625mm < ² > when the shearing adhesive force with respect to a polarizer protective layer (triacetylcellulose film) was measured by the method mentioned later.
“SAT-4238T-JSL”: Sanei Kaken Co., Ltd. It was 56N / 625mm < ² > when the shearing adhesive force with respect to a polarizer protective layer (triacetylcellulose film) was measured by the method mentioned later.
“AS3-303”: manufactured by Fujimori Industry Co., Ltd. It was 40N / 625mm < ² > when the shearing adhesive force with respect to a polarizer protective layer (triacetylcellulose film) was measured by the method mentioned later.
“NBO-0424”: manufactured by Fujimori Industry Co., Ltd. It was 106 N / 625mm < ² > when the shearing adhesive force with respect to a polarizer protective layer (triacetylcellulose film) was measured by the method mentioned later.

[Reference example]
(A) Production of polarizing plate roll First, triacetyl cellulose is used on one side of a polarizer 1 having a thickness of 23 μm made of polyvinyl alcohol to which iodine is adsorbed and oriented, through an adhesive made of an aqueous solution of a polyvinyl alcohol resin. A polarizer protective layer 2 having a thickness of 40 μm was bonded, and a retardation film 3 having a thickness of 25 μm was bonded to the other surface of the polarizer 1 via an acrylic adhesive layer 7 having a thickness of 15 μm. Further, on the surface of the retardation film 3, a sheet-like pressure-sensitive adhesive in which an acrylic pressure-sensitive adhesive layer 8 having a thickness of 25 μm is formed on a separate film 9 made of polyethylene terephthalate having a thickness of 38 μm is provided on the pressure-sensitive adhesive layer 8 side. And a general protective film 6 was bonded to the polarizer protective layer 2 side to prepare a polarizing plate roll 11 having a layer structure shown in FIG.

(B) Measurement of Shear Adhesive Force of Protect Film A 200 mm × 120 mm rectangular sample was cut from the obtained polarizing plate roll 11, the separate film 9 was peeled off, and the glass [Corning Japan Co., Ltd. ) And then fixed to “# 1737” obtained from). Then, after peeling off the protective film 6 provided in advance on the cut polarizing plate, each of the protective films shown above was cut into a 100 mm × 25 mm rectangle as shown in FIG. The sample was bonded so that the 25 mm bonded portion overlapped with the polarizer protective layer 2 of the polarizing plate to obtain a sample for measuring the shear adhesive force. The sample was allowed to stand at room temperature for 2 weeks, and then the protective film 6 was protected using a tensile tester [“AG-1” manufactured by Shimadzu Corporation] in an environment of a temperature of 23 ° C. and a relative humidity of 55%. The shearing adhesive strength was measured by pulling to the side not bonded to the polarizer protective layer 2 (arrow P direction) at a pulling speed of 0.25 mm / min.

[Example 1]
In (a) of the reference example, “AS3-304” manufactured by Fujimori Kogyo Co., Ltd. was bonded to the surface of the polarizer protective layer 2 as a protective film 6 on the pressure-sensitive adhesive layer side, and as shown in FIG. Then, the protective film 6 was wound inside so that a polarizing plate roll 11 was produced. This was stored at room temperature for 2 weeks and then cut into a 90 mm × 50 mm rectangle to produce a sample for curl measurement. Then, the curl amount was measured by the method shown in FIG. 5 for each of the state where the separate film 9 on the adhesive layer 8 side was attached and the state where the separate film 9 was peeled off. The results are shown in Table 1 together with the shear adhesive strength of the protective film.

[Example 2]
The protective film 6 was changed to “SAT-4238T-JSL” manufactured by Sanei Kaken Co., Ltd., and a polarizing plate roll was produced and evaluated in the same manner as in Example 1 except for that. The results are shown in Table 1.

[Example 3]
The protective film 6 was changed to “AS3-303” manufactured by Fujimori Kogyo Co., Ltd., and a polarizing plate roll was prepared and evaluated in the same manner as in Example 1 except for the above. The results are shown in Table 1.

[Comparative Example 1]
The protective film 6 was changed to “NBO-0424” manufactured by Fujimori Kogyo Co., Ltd., and a polarizing plate roll was prepared and evaluated in the same manner as in Example 1 except for the above. The results are shown in Table 1.

  From Table 1, it can be seen that the polarizing plates obtained in Examples 1 to 3 have a smaller curl amount than the polarizing plate obtained in Comparative Example 1, and are within an allowable range of −2 mm to +3 mm. In particular, the polarizing plate obtained in Comparative Example 1 has a larger amount of curl in the state where the separation film is peeled off than in the state where the separation film is attached, whereas the polarization obtained in Examples 1 to 3 The curl amount of the plate hardly changed between the state with the separate film attached and the state with the separate film peeled off. Therefore, according to the method of the present invention, it is possible to produce a polarizing plate in which the curl amount is suppressed.

[Example 4]
A polarizing plate product having a predetermined size is cut from the polarizing plate roll obtained in Examples 1 to 3 and Comparative Example 1 described above, the separation film 9 is peeled off, and the adhesive layer 8 side is attached to a glass substrate for a liquid crystal cell. Combined and pressed with a hand roller. As a result, in Comparative Example 1, even when pressed with a hand roller, the central part of the polarizing plate was not sufficiently adhered to the glass, and floating and bubbles were observed. On the other hand, the thing of Examples 1-3 was adhere | attached favorably to glass.

It is a cross-sectional schematic diagram which shows an example of the laminated constitution of the polarizing plate roll thru | or polarizing plate product manufactured by the method of this invention. It is a cross-sectional schematic diagram which shows the example of another layer structure of the polarizing plate roll thru | or polarizing plate product manufactured by the method of this invention, and shows the layer structure of the polarizing plate roll produced in Examples 1-3 and the comparative example 1. It is also a cross-sectional schematic diagram. It is a cross-sectional schematic diagram which expands and shows the state which winds up a polarizing plate roll. It is a figure which shows typically the state which measures the shearing adhesive force with respect to the polarizer protective film of a protective film, (A) is a longitudinal cross-sectional view, (B) is a top view. It is a perspective view which shows typically the curl amount measurement state of the polarizing plate product cut to the predetermined dimension from the polarizing plate roll.

Explanation of symbols

1 ... Polarizer,
2 ... Polarizer protective layer,
3 ... retardation film,
4, 5 ... Polarizing plate,
6 …… Protect film,
7,8 …… Adhesive layer,
9 …… Separate film,
10, 11 ... Polarizing plate roll or polarizing plate product,
15 …… Glass plate,
21 ... Curled polarizing plate product,
23 …… A virtual surface on the reference surface assuming that the polarizing plate product is not curled,
25 …… Reference plane,
A, B, C, D ... Four corners of the polarizing plate product on the virtual surface,
A1, B1, C1, D1 ... Four corners of curled polarizing plate products
H: Curl height (height from the reference surface to the four corners of the polarizing plate product).

Claims (3)

A polarizer protective layer is bonded to one side of a polarizer made of polyvinyl alcohol resin, a pressure-sensitive adhesive layer is directly provided on the other side of the polarizer, and a pressure-sensitive adhesive layer is provided on the other side of the polarizer. Is a single layer or a plurality of layers, and a separate film is bonded to the outermost pressure-sensitive adhesive layer surface, and a polarizing film having a peelable protective film bonded to the surface of the polarizer protective layer. A method of manufacturing a polarizing plate roll by winding it into a roll,
The protective film has a shear adhesive force to the polarizer protective layer of 80 N / 625 mm ² or less,
A method of manufacturing a polarizing plate roll, wherein the protective film is wound inside.   A polarizer protective layer is bonded to one side of the polarizer, a pressure-sensitive adhesive layer is directly provided on the other side of the polarizer, and a separate film is bonded to the surface of the pressure-sensitive adhesive layer. The method according to claim 1, wherein a polarizing plate having a peelable protective film bonded to the surface is wound up in a roll shape.   A polarizer protective layer is bonded to one side of the polarizer, and a pressure-sensitive adhesive layer is directly provided on the other side of the polarizer. A retardation film, an outer pressure-sensitive adhesive layer, and a separate film are formed on the surface of the pressure-sensitive adhesive layer. The method according to claim 1, wherein the polarizing plate is bonded in order, and a polarizing plate having a peelable protective film bonded to the surface of the polarizer protective layer is rolled up.

Images