JP6457053B2 - Polarizing plate with protective film and liquid crystal panel - Google Patents

Description

  The present invention relates to a polarizing plate with a protective film and a liquid crystal panel.

  The polarizing plate is widely used as a polarized light supplying element and a polarized light detecting element in a display device such as a liquid crystal display device. As a polarizing plate, the thing of the structure which bonded the protective film on the single side | surface or both surfaces of the polarizer using the adhesive agent is common.

  In order to protect the surface of the polarizing plate at the time of storage or in the manufacturing process constituting the liquid crystal panel, for example, as described in Patent Document 1, a peelable protective film (peeling film or surface protection) is used. In some cases, a polarizing plate with a protective film may be obtained. The protective film is peeled off after the polarizing plate is bonded to the liquid crystal cell.

JP 2006-170383 A

  The peeling of the protective film is caused by applying a force in a direction perpendicular to the film surface to the edge of the protective film (peeling starts), and then a force in the direction of the film surface is applied to the caused portion to cause polarization. It peels from the board. The application of force to the protective film at the time of peeling can be performed by gripping the end of the protective film, or can be performed through the peeling tape attached to the surface of the protective film.

  The force that causes the protective film (hereinafter also referred to as “causing force”) and the force that causes the protective film to peel in the surface direction (hereinafter also referred to as “in-plane peeling force”) are: Although the pressure-sensitive adhesive to be adhered can be reduced by making the pressure-sensitive adhesive weak, there may be a problem that the protective film floats or peels off at an unintended timing. Usually, the causing force is larger than the in-plane peeling force.

  In a polarizing plate with a protective film, an excessive force is required to cause the protective film, and peeling of the protective film may be difficult. As a general structure of a polarizing plate, there exists the structure which bonded the optical film on the polarizing film through the adhesive. Even in a polarizing plate with a protective film composed of a polarizing plate having such a configuration, an excessive force is required to cause the protective film, and it may be difficult to remove the protective film.

  An object of this invention is to provide the polarizing plate with a protective film which can reduce the force required to raise a protective film at the time of peeling of a protective film.

  The present invention provides the following polarizing plate with a protective film, a liquid crystal panel, and a method for producing a polarizing plate with a protective film.

[1] A polarizing plate having a polarizing film and an optical film;
A protective film laminated on the surface of the polarizing plate,
The polarizing film, the optical film, the protective film is a polarizing plate with a protective film laminated in this order,
At least one cross section in the laminating direction has an outermost position P1 of the polarizing film in the direction perpendicular to the laminating direction at at least one end in the direction orthogonal to the laminating direction, and the outermost position of the optical film. The outer position P2 is the following (i) to (iii):
(I) position P1 is outside position P2;
(Ii) The position P1 and the position P2 are the same;
(Iii) The position P1 is inside the position P2, and the distance between the position P1 and the position P2 is 1 μm or less.
A polarizing plate with a protective film that satisfies any of the following relationships.

  [2] The polarizing plate with a protective film according to [1], wherein the polarizing film includes a polarizer and a protective film.

[3] The polarizing plate further includes an adhesive layer,
The polarizing plate with a protective film according to [1] or [2], wherein the polarizing film, the pressure-sensitive adhesive layer, the optical film, and the protective film are laminated in this order.

  [4] The polarizing plate with a protective film according to any one of [1] to [3], wherein the end portion is present on a polished end face.

  [5] The polarizing plate with a protective film according to [4], wherein the polished end surface has a shape in which V-shaped grooves and pointed portions are alternately formed.

  [6] The polarizing plate with a protective film according to [4] or [5], wherein the position P1 and the position P2 satisfy the relationship (i).

[7] A liquid crystal cell, and a polarizing plate with a protective film according to [3],
The liquid crystal panel in which the liquid crystal cell, the polarizing film, the pressure-sensitive adhesive layer, the optical film, and the protective film are laminated in this order.

[8] A step of obtaining a film laminate in which a polarizing film, an optical film, and a protective film are laminated in this order;
Polishing at least one end face of the film laminate, and at the end face, an outermost position P1 of the polarizing film and an outermost position P2 of the optical film with respect to a direction orthogonal to the laminating direction; Are the following (i) to (iii):
(I) position P1 is outside position P2;
(Ii) The position P1 and the position P2 are the same;
(Iii) The position P1 is inside the position P2, and the distance between the position P1 and the position P2 is 1 μm or less.
And a process for satisfying any one of the following conditions: A method for producing a polarizing plate with a protective film.

  According to the polarizing plate with a protective film of the present invention, the force required to cause the protective film can be reduced when the protective film is peeled off.

It is sectional drawing of the lamination direction which shows an example of the polarizing plate with a protective film which concerns on this invention (Example 3). It is sectional drawing of the lamination direction which shows an example of the polarizing plate with a protective film which concerns on this invention. It is sectional drawing of the lamination direction which shows an example of the polarizing plate with a protective film which concerns on this invention (Example 1). It is sectional drawing of the lamination direction which shows an example of the polarizing plate with a protective film which concerns on this invention (Example 2). It is sectional drawing which shows an example of the layer structure of the polarizing plate with a protective film which concerns on this invention. It is sectional drawing which shows an example of the layer structure of the polarizing plate with a protective film which concerns on this invention. It is a schematic perspective view of the end surface processing apparatus which uses the end surface of a polarizing plate laminated body for grinding | polishing process. It is a schematic diagram which shows the peeling method of a protective film. It is a schematic diagram which shows an example of the sticking direction of a peeling tape. It is a schematic diagram which shows an example of the sticking direction of a peeling tape. It is a schematic diagram which shows a peeling angle. 6 is a cross-sectional view in the stacking direction of a polarizing plate with a protective film of Comparative Example 1. FIG. It is sectional drawing of the lamination direction of the polarizing plate with a protective film of the comparative example 2. FIG. It is sectional drawing of the lamination direction of the polarizing plate with a protective film of the comparative example 3. 6 is a schematic diagram showing a method of Evaluation Test 1. FIG. It is a top perspective view which shows a square-shaped polarizing plate with a protective film.

<Polarizing plate with protective film>
(1) Configuration of Polarizing Plate with Protect Film A polarizing plate with a protective film according to the present invention includes a polarizing plate having a polarizing film (A) and an optical film (C), and a protective film laminated on the surface of the polarizing plate ( D), and a polarizing film (A), an optical film (C), and a protective film (D) are laminated in this order. In the polarizing plate, the optical film (C) is laminated by, for example, the pressure-sensitive adhesive layer (B). In this case, the polarizing plate with a protective film includes the polarizing film (A), the pressure-sensitive adhesive layer (B), The optical film (C) and the protective film (D) are laminated in this order.

An example of the layer structure of the polarizing plate with a protective film according to the present invention will be described with reference to FIG.
FIG. 1 shows a cross-sectional view in the laminating direction of a polarizing plate with a protective film. As shown in FIG. 1, a polarizing plate 111 with a protective film includes a separate film 70, a first pressure-sensitive adhesive layer 31, a protective film 22, a polarizer 10, and a laminate composed of the protective film 22 and the polarizer 10. The film 20 corresponds to the polarizing film (A)), the third pressure-sensitive adhesive layer 32 (corresponding to the pressure-sensitive adhesive layer (B)), and the brightness enhancement film 50 (corresponding to the optical film (C)) in the order described above. A polarizing plate 100 that is laminated and a protective film 60 (corresponding to a protective film (D)) that is laminated on the surface of the polarizing plate 100 on the brightness enhancement film 50 side. The protective film 60 is composed of a base film 61 and a second pressure-sensitive adhesive layer 62 laminated thereon, and is laminated and laminated on the polarizing plate 100 via the second pressure-sensitive adhesive layer 62.

At least one cross section in the laminating direction of the polarizing plate with a protective film of the present invention is at the outermost side of the polarizing film (A) with respect to the direction perpendicular to the laminating direction at at least one end in the direction perpendicular to the laminating direction. A position P1 (hereinafter, this position may be simply referred to as “position P1”) and an outermost position P2 of the optical film (C) (hereinafter, this position may also be simply referred to as “position P2”). Are the following (i) to (iii):
(I) position P1 is outside position P2;
(Ii) The position P1 and the position P2 are the same;
(Iii) The position P1 is inside the position P2, and the distance L between the position P1 and the position P2 is 1 μm or less.
Satisfy any relationship. The edge part shown in FIG. 1 of the polarizing plate 111 with a protective film satisfy | fills the relationship of said (iii).

  That the relationship between the position P1 and the position P2 satisfies any one of the above (i) to (iii) is that the position that is inside the position P2 and the distance from the position P2 is 1 μm is the reference point. In this case, the position P1 means to be located outside the reference point.

The said characteristic regarding the position P1 and the position P2 of the polarizing plate with a protective film of this invention is demonstrated more concretely using FIG. The polarizing plate with a protective film is usually rectangular. FIG. 16 is a top perspective view schematically showing a rectangular polarizing plate with a protective film. The square-shaped polarizing plate 110 with a protective film has four end surfaces 110a, 110b, 110c, and 110d (in the present specification, “end surface” means side end surfaces unless otherwise specified). In the polarizing plate 110 with a protective film of the present invention, at least one cross section in the stacking direction (arrow direction) (for example, the cross sections 115 and 116 passing through two opposing end faces, preferably the long side or the short side of the polarizing plate with a protective film). The cross section parallel to the side) is at least one end in a direction orthogonal to the stacking direction (arrow direction) (for example, the end 115b or the end 115d in the case of the cross section 115, the end 116a or the end in the case of the cross section 116). In the part 116 c ), the position P1 and the position P2 are configured so as to satisfy any one of the above (i) to (iii) with respect to the direction orthogonal to the stacking direction. The above-described end portions (for example, the end portions 115b, 115d, 116a, and 116c) are present on any of the end surfaces 110a, 110b, 110c, and 110d.

  The polarizing plate with a protective film of the present invention has an end that satisfies any of the above relationships (i) to (iii), and causes the protective film by starting peeling of the protective film from the end. Can be reduced. The polarizing plate with a protective film preferably has an end surface that satisfies any of the above relationships (i) to (iii) in the entire region. In this case, even if it is a case where peeling of a protection film is started from any edge part of this end surface, the force required in order to cause a protection film can be reduced. Moreover, in the polarizing plate with a protective film, it is more preferable that all the four end faces satisfy the relationship (i) to (iii) in the entire region. In this case, even if it is a case where peeling of a protective film is started from which edge part, the force required in order to cause a protective film can be reduced.

  The end portion of the polarizing plate 111 with a protective film shown in FIG. 1 has a distance L between the position P1 and the position P2 of 1 μm or less and satisfies the relationship (iii) above. In the protective film-attached polarizing plate 111, the positional relationship between the positions P1 and P2 is the same as the relationship shown in FIG. In the polarizing plate 111 with a protective film, the end positions of the polarizing film (A) and the optical film (C) are adjusted so as to satisfy the relationship (iii).

  FIG. 2 is a cross-sectional view showing another example of a polarizing plate with a protective film. The end part shown in FIG. 2 of the polarizing plate 112 with the protective film has a position P1 outside the position P2, and satisfies the relationship (i). The polarizing plate 112 with a protective film is assumed to have the same positional relationship between the positions P1 and P2 as shown in FIG. In the polarizing plate 112 with a protective film, the end positions of the polarizing film (A) and the optical film (C) are adjusted so as to satisfy the relationship (i).

  1 and 2 specifically show the layer structure of the polarizing plate with a protective film and the positional relationship between the positions P1 and P2. Therefore, in the example shown in FIG. 1 or FIG. 2, if the layer configuration of the polarizing plate with a protective film and the positional relationship between the positions P1 and P2 satisfy the relationship shown in FIG. A mode in which other conditions such as the relative thickness of each layer and the relative width of each layer are different from those shown in FIG. 1 or 2 is also included. As shown in FIGS. 1 and 2, the polarizing laminated film (A) and the optical film (C) are laminated via an adhesive layer (the third adhesive layer 32 in FIGS. 1 and 2). In the polarizing plate with a protective film, since the elastic modulus of the adhesive layer is lower than that of the protective film, the adhesive layer easily absorbs the force that causes the protective film, and requires a large force to cause the protective film. There is. In particular, when the storage elastic modulus at a temperature of 20 ° C. of the pressure-sensitive adhesive layer interposed between the polarizing laminate film (A) and the optical film (C) is 0.1 MPa or less, further 0.08 MPa or less. In such a case, the force that causes the protective film is absorbed by the pressure-sensitive adhesive layer, and thus a large force may be required to cause the protective film. According to the present invention, also in the polarizing plate with a protective film, a pressure-sensitive adhesive layer having a storage elastic modulus at a temperature of 20 ° C. of 0.1 MPa or less is interposed between the polarizing laminated film (A) and the optical film (C). The force required to pull up the protective film can be reduced. In addition, the storage elastic modulus at the temperature of 20 degreeC of the adhesive layer interposed between a polarizing laminated film (A) and an optical film (C) is 0.01 MPa or more normally.

  The storage elastic modulus of the pressure-sensitive adhesive layer can be measured using a commercially available rheometer. Specifically, MCR301 manufactured by Anton Paar can be used. The measurement conditions can be as follows. In addition, the storage elastic modulus shown in this specification is a value measured using the apparatus and measurement conditions described herein.

Measuring jig: Parallel plate with a diameter of 25 mm Temperature: 20 ° C
Frequency: 1Hz
Distortion: 1%
Normal force: 0N
Sample shape: a laminate in which the pressure-sensitive adhesive layer is laminated to 210 μm For the polarizing plate with a protective film, the adjustment of the end positions of the polarizing film (A) and the optical film (C) may be performed at the time of lamination, After being laminated, it may be performed by end face processing such as cutting and polishing. If end face processing is performed on a polarizing plate with a protective film, a greater force may be required to cause the protective film. As one of such factors, it is considered that the cross-sectional shape of the protective film changes due to end face processing, and force dispersion is likely to occur. According to the present invention, the force required to pull up the protective film can be reduced even in the polarizing plate with the protective film subjected to end face processing. After the lamination, the protective film-attached polarizing plate may be cut into a shape such as a rectangle or a predetermined size according to the liquid crystal cell. Moreover, in order to improve the dimensional accuracy of a polarizing plate and to make an end surface smooth, the end surface may be polished. When the end face is polished, the end face is likely not to be flush. The end face processing of the polarizing plate with a protective film is usually performed in a state where a plurality of polarizing plates are stacked and pressed from above and below and fixed. In this case, each layer constituting the polarizing plate is temporarily deformed (thinned and spread) by the pressing force from above and below, and the end face is processed in a deformed state. The degree of deformation depends on the magnitude of the pressing force from above and below, the layer configuration and size of the polarizing plate, the thickness of each layer, and the like. Therefore, the end face shape at the time of end face processing is different from the end face shape in a state where the pressing force from above and below is released and the deformation is restored.

  3 and 4 are cross-sectional views showing an example of a polarizing plate with a protective film according to the present invention, which has been subjected to such end face processing. 3 and 4 are different in the protective film 60 in that the angle of the end surface with respect to the surface is an obtuse angle (FIG. 3) or an acute angle (FIG. 4). 3 and 4 specifically show the layer configuration of the polarizing plate with a protective film and the positional relationship between the position P1 and the position P2. Therefore, in the example shown in FIG. 3 or FIG. 4, if the layer configuration of the polarizing plate with a protective film and the positional relationship between the positions P1 and P2 satisfy the relationship shown in FIG. A mode in which other conditions such as the relative thickness of each layer and the relative width of each layer are different from those shown in FIG. 3 or 4 is also included. In the polarizing plates 113 and 114 with protective film, the positional relationship between the positions P1 and P2 is the same as the positional relationship shown in FIG.

  The end faces of the protective film-attached polarizing plates 113 and 114 shown in FIGS. 3 and 4 have shapes in which V-shaped grooves and pointed portions are alternately formed (hereinafter, such shapes are also referred to as “zigzag shapes”). including. The polarizing plates 113 and 114 with a protective film are manufactured by polishing four end surfaces while being pressed and fixed from above and below. The end face (hereinafter also referred to as “polishing end face”) that has been polished so as to be substantially flush with the state of being deformed by pressing from above and below and is pressed (hereinafter also referred to as “polishing end face”) has a V-groove as shown in FIGS. There may be a shape in which the ridges and the pointed portions are alternately formed. The polishing end face is distinguished from an end face having no polishing flaw in that it has a polishing flaw. A polarizing plate with a protective film subjected to such end face polishing can realize high dimensional accuracy.

The pressure-sensitive adhesive layer tends to be a V-shaped groove having a V-shaped cross section when the pressing force is released after polishing because the pressure-sensitive adhesive layer has higher viscoelasticity than the adjacent layer and tends to be deformed by pressing from above and below. . The V-shaped groove is formed at a position where the degree of polishing is larger than the surrounding area. On the other hand, a layer having low viscoelasticity tends to have a small degree of deformation due to pressing from above and below, and therefore, when the pressing force is released after polishing, there is a tendency to form a pointed portion having a pointed cross section. The pointed portion is formed at a position where the degree of polishing is smaller than the surrounding area. The formation position of the V-shaped groove and the pointed portion, the depth of each V-shaped groove, and the height of each pointed portion are adjusted as appropriate by adjusting the material and thickness of each layer, the pressing force from above and below, and the like. be able to.
The polarizing plates 113 and 114 with a protective film shown in FIGS. 3 and 4 have their end surfaces polished so as to satisfy the relationship (i).

  The polarizing plate with a protective film according to the present invention has a relationship of any one of (i) to (iii) above when the protective film is peeled off (normally, the relationship at the time of bonding to the liquid crystal cell is maintained). Having an end that satisfies In particular, when the end surface has a zigzag shape as shown in FIGS. 3 and 4, it is preferable to have an end portion that satisfies the relationship (i). By setting the end portion of the end surface to a position where the peeling of the protective film is started, the force required to cause the protective film can be further reduced.

  Conventionally, when the position where peeling is started is provided on a polished end face and a zigzag end face, an excessive force may be required to lift the protective film. It is expected that the force applied at the time of peeling off the protective film does not efficiently act as a lifting force for the protective film. Even in such a case, the force required for pulling up the protective film can be further reduced by having the end satisfying the relationship (i) and pulling up the protective film from this end. When satisfying the relationship (i), the distance L in the width direction between the position P1 and the position P2 is preferably 20 μm or less, more preferably 1 μm or more and 10 μm or less, and 2 μm or more and 8 μm or less. Is more preferable. In the case where the pressure-sensitive adhesive layer (B) is provided between the polarizing film (A) and the optical film (C), a V-shaped groove tends to be easily formed at the position of the pressure-sensitive adhesive layer (B). There is a tendency to be an end face having a V-shaped groove between the polarizing film (A) and the optical film (C). In addition, although the size of a polarizing plate is not limited, For example, it is a square shape whose length of one side is 5-30 cm.

  The distance L in the width direction between the position P1 and the position P2 can be measured using, for example, a laser microscope capable of observing a three-dimensional surface shape. Specifically, the distance L can be measured in a non-contact manner by scanning the end face shape of the polarizing plate with a protective film with a laser with a 20 × or 50 × objective lens. An example of the laser microscope is LEXT (registered trademark) OLS4100 manufactured by Olympus Corporation.

  3 and 4 show an example in which the polished end face has a zigzag shape, and the case where the deepest part of the V-shaped groove and the top part of the pointed part are straight is shown as a zigzag shape. However, the present invention is not limited to this, and the connecting portion between the deepest portion of the V-shaped groove and the apex of the pointed portion may be a curve or a combination of a curve and a straight line. Further, in the zigzag shape, the deepest part of the V-shaped groove and the top part of the pointed part may be rounded.

  The layer structure of the polarizing plate with a protective film is not limited to the examples shown in FIGS. 5 and 6 illustrate a layer configuration different from the examples shown in FIGS. 5 and 6, although the sectional shape of the end face of the protective film-attached polarizing plate is abbreviated as a straight line, the above description based on FIGS. 1 to 4 is cited.

  The polarizing plate with a protective film shown in FIG. 5 includes a separate film 70, a first pressure-sensitive adhesive layer 31, a protective film 22, a polarizer 10, a protective film 21, and a protective film 22, a polarizer 10, and a protective film. 21), a third pressure-sensitive adhesive layer 32 (corresponding to the pressure-sensitive adhesive layer (B)), and a brightness enhancement film 50 (corresponding to the optical film (C)). Are laminated in the above order, and a protective film 60 (corresponding to the protective film (D)) laminated on the surface of the polarizing plate 100 is provided.

  The polarizing plate included in the polarizing plate with a protective film shown in FIG. 6 does not have the protective film 22 and is shown in FIG. 5 except that the first pressure-sensitive adhesive layer 31 is directly laminated on the surface of the polarizer 10. It has the same layer structure as the polarizing plate. In the polarizing plate with a protective film shown in FIG. 6, a laminated film 20 composed of the polarizer 10 and the protective film 21 corresponds to the polarizing film (A).

  Although illustration is abbreviate | omitted in FIGS. 1-6, in the polarizing film 20, bonding with the polarizer 10 and the protective films 21 and 22 can be performed using an adhesive agent. In this specification, an adhesive layer made of an adhesive is also a constituent element of the polarizing film 20.

(2) Protect film (D)
The protect film 60 includes a base film 61 and a second pressure-sensitive adhesive layer 62 laminated thereon. The protective film 60 is a film for protecting the surface of the polarizing plate 100. For example, after the polarizing plate with a protective film is bonded to an image display element such as a liquid crystal cell or another optical member, the second adhesive that the protective film 60 has. The agent layer 62 is peeled off and removed. The thickness of the protective film is, for example, 30 to 100 μm.

  The resin constituting the base film 61 is, for example, a thermoplastic resin such as a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, a polyester resin such as polyethylene terephthalate or polyethylene naphthalate, or a polycarbonate resin. Can be. Polyester resins such as polyethylene terephthalate are preferable. Although the base film 61 may have a single layer structure or a multilayer structure, it is preferably a single layer structure from the viewpoints of manufacturability and manufacturing cost. The base film 61 may be a uniaxially stretched film or a biaxially stretched film, but is preferably a biaxially stretched film from the viewpoint of the mechanical strength, ease of production, production cost, etc. of the film. .

  For the second pressure-sensitive adhesive layer 62, the description of the first pressure-sensitive adhesive layer 31 and the third pressure-sensitive adhesive layer 32 described later is cited.

(3) Polarizer The polarizer 10 has a property of absorbing linearly polarized light having a vibration surface parallel to the absorption axis and transmitting linearly polarized light having a vibration surface orthogonal to the absorption axis (parallel to the transmission axis). An absorptive polarizer, and a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film can be suitably used. The polarizer 10 is, for example, a step of uniaxially stretching a polyvinyl alcohol resin film; a step of adsorbing a dichroic dye by dyeing the polyvinyl alcohol resin film with a dichroic dye; a dichroic dye being adsorbed It can be produced by a method comprising a step of treating a polyvinyl alcohol resin film with an aqueous boric acid solution; and a step of washing with water after the treatment with the boric acid aqueous solution.

  As the polyvinyl alcohol resin, a saponified polyvinyl acetate resin can be used. Examples of the polyvinyl acetate resin include, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate, copolymers with other monomers copolymerizable with vinyl acetate. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, acrylamides having ammonium groups, and the like.

  The saponification degree of the polyvinyl alcohol resin is usually 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The average degree of polymerization of the polyvinyl alcohol-based resin is usually 1000 to 10000, and preferably 1500 to 5000. The average degree of polymerization of the polyvinyl alcohol resin can be determined according to JIS K 6726.

  What formed such a polyvinyl alcohol-type resin into a film is used as a raw film of the polarizer 10 (polarizing film). The method for forming the polyvinyl alcohol-based resin into a film is not particularly limited, and a known method is employed. The thickness of the polyvinyl alcohol-based raw film is not particularly limited, but in order to make the thickness of the polarizer 10 15 μm or less, a thickness of usually 5 to 35 μm is used, and preferably 20 μm or less. If an attempt is made to stretch a polyvinyl alcohol-based raw film having a thickness of more than 35 μm to obtain a polarizer 10 having a thickness of 15 μm or less, it is necessary to increase the stretching ratio. Even when the thickness of the polarizer 10 is set to 15 μm or less, the temperature is high. Dimensional shrinkage under the environment increases. Moreover, when thickness is less than 5 micrometers, the handleability at the time of extending | stretching falls and it becomes easy to produce malfunctions, such as a cutting | disconnection at the time of polarizer manufacture.

  Uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before, simultaneously with, or after dyeing the dichroic dye. When uniaxial stretching is performed after dyeing, this uniaxial stretching may be performed before boric acid treatment or during boric acid treatment. Moreover, you may uniaxially stretch in these several steps.

  In uniaxial stretching, it may be uniaxially stretched between rolls having different peripheral speeds, or may be uniaxially stretched using a hot roll. Further, the uniaxial stretching may be dry stretching in which stretching is performed in the air, or may be wet stretching in which stretching is performed in a state where a polyvinyl alcohol-based resin film is swollen using a solvent or water. The draw ratio is usually 3 to 8 times.

  As a method for dyeing a polyvinyl alcohol-based resin film with a dichroic dye, for example, a method of immersing the film in an aqueous solution containing the dichroic dye is employed. As the dichroic dye, iodine or a dichroic organic dye is used. In addition, it is preferable that the polyvinyl alcohol-type resin film performs the immersion process to water before a dyeing process.

As the dyeing treatment with iodine, a method of immersing a polyvinyl alcohol resin film in an aqueous solution containing iodine and potassium iodide is usually employed. The content of iodine in this aqueous solution is usually 0.01 to 1 part by weight per 100 parts by weight of water. The content of potassium iodide is usually 0.5 to 20 parts by weight per 100 parts by weight of water. Moreover, the temperature of this aqueous solution is 20-40 degreeC normally. On the other hand, as a dyeing treatment with a dichroic organic dye, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic organic dye is usually employed. The aqueous solution containing the dichroic organic dye may contain an inorganic salt such as sodium sulfate as a dyeing assistant. The content of the dichroic organic dye in this aqueous solution is usually 1 × 10 ⁻⁴ to 10 parts by weight per 100 parts by weight of water. The temperature of this aqueous solution is usually 20 to 80 ° C.

As boric acid treatment after dyeing with a dichroic dye, a method of immersing a dyed polyvinyl alcohol-based resin film in a boric acid-containing aqueous solution is usually employed. When iodine is used as the dichroic dye, the boric acid-containing aqueous solution preferably contains potassium iodide.
The amount of boric acid in the boric acid-containing aqueous solution is usually 2 to 15 parts by weight per 100 parts by weight of water. The amount of potassium iodide in this aqueous solution is usually 0.1 to 15 parts by weight per 100 parts by weight of water. The temperature of this aqueous solution can be 50 ° C. or higher, for example, 50 to 85 ° C.

  The polyvinyl alcohol resin film after the boric acid treatment is usually washed with water. The water washing treatment can be performed, for example, by immersing a boric acid-treated polyvinyl alcohol resin film in water. The temperature of water in the water washing treatment is usually 5 to 40 ° C.

  The polarizer 10 is obtained by performing a drying process after washing with water. The drying process can be performed using a hot air dryer or a far infrared heater. The thickness of the polarizer 10 is 15 μm or less, and preferably 10 μm or less. Setting the thickness of the polarizer 10 to 15 μm or less is advantageous in reducing the thickness of the polarizing plate 100 and, in turn, the image display device. The thickness of the polarizer 10 is usually 2 μm or more (for example, 5 μm or more).

  By the drying process, the moisture content of the polarizer 10 is reduced to a practical level. The moisture content is usually 5 to 20% by weight, and preferably 8 to 15% by weight. When the moisture content is less than 5% by weight, the flexibility of the polarizer 10 is lost, and the polarizer 10 may be damaged or broken after drying. Moreover, when the moisture content exceeds 20% by weight, the thermal stability of the polarizer 10 may be inferior.

(4) Protective film The protective films 21 and 22 that can be laminated on one or both sides of the polarizer 10 are thermoplastic resins having translucency (preferably optically transparent), for example, chain polyolefin resins. (Polypropylene resins, etc.), polyolefin resins such as cyclic polyolefin resins (norbornene resins, etc.); cellulose resins such as triacetyl cellulose and diacetyl cellulose; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; Polycarbonate resins; (meth) acrylic resins such as methyl methacrylate resins; polystyrene resins; polyvinyl chloride resins; acrylonitrile / butadiene / styrene resins; acrylonitrile / styrene resins; polyvinyl acetate resins; salt Polyvinyl resin; Polyamide resin; Polyacetal resin; Modified polyphenylene ether resin; Polysulfone resin; Polyether sulfone resin; Polyarylate resin; Polyamideimide resin; Polyimide resin it can. Among these, it is preferable to use a polyolefin resin or a cellulose resin. In this specification, “(meth) acrylic resin” represents at least one selected from the group consisting of acrylic resins and methacrylic resins. The same applies to other terms with “(meta)”.

  Examples of the chain polyolefin-based resin include a homopolymer of a chain olefin such as a polyethylene resin and a polypropylene resin, and a copolymer composed of two or more chain olefins.

  Cyclic polyolefin resin is a general term for resins that are polymerized using a cyclic olefin as a polymerization unit. Specific examples of cyclic polyolefin resins include ring-opening (co) polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers of cyclic olefins and chain olefins such as ethylene and propylene (typically Are random copolymers), graft polymers obtained by modifying them with unsaturated carboxylic acids or derivatives thereof, and hydrides thereof. Among these, norbornene resins using norbornene monomers such as norbornene and polycyclic norbornene monomers as cyclic olefins are preferably used.

  Cellulosic resins are those in which some or all of the hydrogen atoms in the hydroxyl groups of cellulose obtained from raw material cellulose such as cotton linter and wood pulp (hardwood pulp, conifer pulp) are substituted with acetyl groups, propionyl groups and / or butyryl groups. Further, it refers to a cellulose organic acid ester or a cellulose mixed organic acid ester. For example, cellulose acetate, propionate, butyrate, and mixed esters thereof can be used. Among these, triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, and cellulose acetate butyrate are preferable.

  The (meth) acrylic resin is a polymer containing a structural unit derived from a (meth) acrylic monomer. The polymer is typically a polymer containing a methacrylic acid ester. Preferably, it is a polymer in which the proportion of structural units derived from methacrylic acid esters is 50% by weight or more based on the total structural units. The (meth) acrylic resin may be a methacrylic acid ester homopolymer or a copolymer containing structural units derived from other polymerizable monomers. In this case, the proportion of structural units derived from other polymerizable monomers is preferably 50% or less with respect to the total structural units.

  The methacrylic acid ester that can constitute the (meth) acrylic resin is preferably an alkyl methacrylate. Examples of alkyl methacrylates include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate. And alkyl methacrylate having 1 to 8 carbon atoms in the alkyl group, such as 2-hydroxyethyl methacrylate. Carbon number of the alkyl group contained in the methacrylic acid alkyl ester is preferably 1 to 4. In the (meth) acrylic resin, methacrylic acid esters may be used alone or in combination of two or more.

  As said other polymerizable monomer which can comprise a (meth) acrylic-type resin, the compound which has a polymerizable carbon-carbon double bond in an acrylate ester and another molecule | numerator can be mentioned. Other polymerizable monomers may be used alone or in combination of two or more. As the acrylic acid ester, an acrylic acid alkyl ester is preferable. Examples of the alkyl acrylate ester include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, and cyclohexyl acrylate. And alkyl acrylates having 1 to 8 carbon atoms in the alkyl group such as 2-hydroxyethyl acrylate. Carbon number of the alkyl group contained in the acrylic acid alkyl ester is preferably 1 to 4. In the (meth) acrylic resin, acrylic acid esters may be used alone or in combination of two or more.

  Other compounds having a polymerizable carbon-carbon double bond in the molecule include vinyl compounds such as ethylene, propylene and styrene, and vinylcyan compounds such as acrylonitrile. Other compounds having a polymerizable carbon-carbon double bond in the molecule may be used alone or in combination of two or more.

  Although the thickness of the protective films 21 and 22 is 1-100 micrometers normally, it is preferable that it is 5-60 micrometers from viewpoints, such as intensity | strength and a handleability, and it is more preferable that it is 5-50 micrometers. When the thickness is within this range, the polarizer 10 is mechanically protected, and the polarizer 10 does not contract even when exposed to a humid heat environment, and stable optical characteristics can be maintained.

  The polarizing plate 100 may have a configuration that does not include one or both of the protective films 21 and 22 from the viewpoint of thinning. Further, as a configuration without the protective film 21, an optical film (C) described later may have the function of the protective film 21.

  When a protective film is laminated | stacked only on one side of the polarizer 10, the activity similar to the below-mentioned active energy ray hardening adhesive is provided on the surface on the opposite side to the surface where the protective film in the polarizer 10 is laminated | stacked. A protective layer formed from the energy ray curable resin composition can also be provided. By providing the protective layer, even when the protective film is provided only on one surface of the polarizer 10, curling due to humidity change and deterioration of the polarizer 10 can be more effectively suppressed. In this specification, such a protective layer is also a constituent element of the polarizing film (A).

  When a protective film is bonded to both surfaces of the polarizer 10, these protective films may be made of the same kind of thermoplastic resin or may be made of different types of thermoplastic resins. Moreover, the thickness may be the same or different. Furthermore, they may have the same phase difference characteristics or different phase difference characteristics.

  At least one of the protective films 21 and 22 has a hard coat layer, an antiglare layer, a light diffusing layer, a retardation layer (a quarter wavelength retardation) on the outer surface (the surface opposite to the polarizer 10). A retardation layer having a value), an antireflection layer, an antistatic layer, a surface treatment layer (coating layer) such as an antifouling layer, or an optical layer.

  The protective films 21 and 22 can contain one or more additives. Examples of additives include ultraviolet absorbers, rubber particles, lubricants, dispersants, heat stabilizers, infrared absorbers, antistatic agents, and antioxidants.

(5) Adhesive layer The protective films 21 and 22 can be bonded to the polarizer 10 through an adhesive layer, for example. As the adhesive for forming the adhesive layer, a water-based adhesive, an active energy ray-curable adhesive, or a thermosetting adhesive can be used, preferably an aqueous adhesive or an active energy ray-curable adhesive. .

  Examples of the water-based adhesive include an adhesive made of a polyvinyl alcohol-based resin aqueous solution, an aqueous two-component urethane emulsion adhesive, and the like. Among these, a water-based adhesive composed of a polyvinyl alcohol-based resin aqueous solution is preferably used. Polyvinyl alcohol resins include vinyl alcohol homopolymers obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. A polyvinyl alcohol copolymer obtained by saponifying a polymer, or a modified polyvinyl alcohol polymer obtained by partially modifying the hydroxyl group thereof can be used. The water-based adhesive can contain a crosslinking agent such as an aldehyde compound (glyoxal, etc.), an epoxy compound, a melamine compound, a methylol compound, an isocyanate compound, an amine compound, and a polyvalent metal salt.

  When using a water-based adhesive, it is preferable to carry out a drying step for removing water contained in the water-based adhesive after the polarizer 10 and the protective films 21 and 22 are bonded together. A curing step for curing may be provided after the drying step. The temperature during curing is usually 20 to 45 ° C.

  The active energy ray-curable adhesive refers to an adhesive that cures by irradiating active energy rays such as ultraviolet rays and electron beams, for example, a curable composition containing a polymerizable compound and a photopolymerization initiator, Examples thereof include a curable composition containing a photoreactive resin, a curable composition containing a binder resin and a photoreactive crosslinking agent. An ultraviolet curable adhesive is preferable. Examples of the polymerizable compound include photopolymerizable monomers such as photocurable epoxy monomers, photocurable (meth) acrylic monomers, and photocurable urethane monomers, and oligomers derived from the photopolymerizable monomers. it can. As a photoinitiator, what contains the substance which generate | occur | produces active species like a neutral radical, an anion radical, and a cation radical by irradiation of an active energy ray can be mentioned. As an active energy ray-curable adhesive containing a polymerizable compound and a photopolymerization initiator, a curable composition containing a photocurable epoxy monomer and a cationic photopolymerization initiator, a photocurable (meth) acrylic monomer, and light A curable composition containing a radical polymerization initiator or a mixture of these curable compositions can be preferably used.

As the photocurable epoxy monomer, an alicyclic epoxy compound is preferable. An alicyclic epoxy compound refers to a compound having one or more structures in the molecule forming an oxirane ring together with carbon atoms of the alicyclic ring. An alicyclic epoxy compound may be used individually by 1 type, and may use 2 or more types together. The “structure in which an oxirane ring is formed together with the carbon atom of the alicyclic ring” is a group in which one or a plurality of hydrogen atoms are removed from (CH ₂ ) _m in the structure shown below. In the following formula, m is an integer of 2 to 5.

Accordingly, a compound in which a group in a form in which one or a plurality of hydrogen atoms in (CH ₂ ) _m are removed is bonded to another chemical structure can be an alicyclic epoxy compound. One or more hydrogen atoms in (CH ₂ ) _m may be appropriately substituted with a linear alkyl group such as a methyl group or an ethyl group. Among alicyclic epoxy compounds, alicyclic epoxy compounds having an oxabicyclohexane ring (m = 4 in the above formula) and an oxabicycloheptane ring (m = 5 in the above formula) are excellent in adhesion. It is preferable at the point which shows property. Specific examples of the alicyclic epoxy compounds that are preferably used are shown below.

  When an active energy ray-curable adhesive is used, the polarizer 10 and the protective films 21 and 22 are bonded together, and then a drying process is performed as necessary, followed by irradiation with active energy rays to cure the active energy ray. A curing step for curing the adhesive is performed. Therefore, when an active energy ray-curable adhesive is used, the adhesive layer is the cured product layer. The light source of the active energy ray is not particularly limited, but ultraviolet light having a light emission distribution at a wavelength of 400 nm or less is preferable. Specifically, the low pressure mercury lamp, the medium pressure mercury lamp, the high pressure mercury lamp, the ultrahigh pressure mercury lamp, the chemical lamp, the black light lamp, the micro A wave excitation mercury lamp, a metal halide lamp, etc. can be used.

  In laminating the polarizer 10 and the protective films 21 and 22, in order to improve the adhesion, at least one of these laminating surfaces can be subjected to saponification treatment, corona treatment, plasma treatment or the like. .

  When protective films are bonded to both surfaces of the polarizer 10, the adhesive for bonding these protective films may be the same type of adhesive or different types of adhesives.

(6) Optical film (C)
The polarizing plate 100 has the optical film (C) laminated | stacked on the polarizer 10 through the 3rd adhesive layer 32 (equivalent to an adhesive layer (B)). Representative examples of the optical film (C) are the brightness enhancement film 50 and the retardation film. The optical film (C) may be a protective film as described above.

  The brightness enhancement film 50 is also referred to as a reflective polarizing film, and a polarization conversion element having a function of separating outgoing light from a light source (backlight) into transmitted polarized light and reflected polarized light or scattered polarized light is used. By arranging the brightness enhancement film 50 on the polarizer 10, the emission efficiency of linearly polarized light emitted from the polarizer 10 can be improved by using retroreflected light that is reflected polarized light or scattered polarized light.

  The brightness enhancement film 50 can be, for example, an anisotropic reflective polarizer. An example of the anisotropic reflective polarizer is an anisotropic multiple thin film that transmits linearly polarized light in one vibration direction and reflects linearly polarized light in the other vibration direction, and a specific example thereof is “DBEF” manufactured by 3M. (See JP-A-4-268505). Another example of the anisotropic reflective polarizer is a composite of a cholesteric liquid crystal layer and a λ / 4 plate, and a specific example thereof is “PCF” manufactured by Nitto Denko (see JP-A-11-231130). ). Yet another example of an anisotropic reflective polarizer is a reflective grid polarizer, a specific example of which is a metal grid reflective polarizer that emits reflected polarized light even in the visible light region by finely processing the metal (US Patent). No. 6288840, etc.), and a film obtained by adding metal fine particles to a polymer matrix and stretching (see JP-A-8-184701, etc.).

A surface activation treatment may be performed in advance on the bonding surface of the brightness enhancement film 50 with the third pressure-sensitive adhesive layer 32. Thereby, it can be set as the polarizing plate 100 excellent in wet heat durability which does not produce peeling easily between the 3rd adhesive layer 32 and the brightness improvement film 50 in a wet heat environment.
As the surface activation treatment, dry treatment such as corona treatment, plasma treatment, discharge treatment (glow discharge treatment, etc.), flame treatment, ozone treatment, UV ozone treatment, ionizing active ray treatment (ultraviolet treatment, electron beam treatment, etc.) And wet treatment such as ultrasonic treatment using a solvent such as water and acetone, alkali treatment, and anchor coat treatment. These processes may be performed alone or in combination of two or more. Among these, corona treatment and plasma treatment are preferable for continuously treating a roll-shaped film.

  On the outer surface of the brightness enhancement film 50, a hard coat layer, an antiglare layer, a light diffusion layer, a retardation layer (such as a retardation layer having a retardation value of ¼ wavelength), an antireflection layer, an antistatic layer, and an antifouling layer A surface treatment layer (coating layer) such as a layer or an optical layer may be provided. By forming such a layer, the adhesion to the backlight tape and the uniformity of the display image can be improved. Although the thickness of the brightness enhancement film 50 is usually 10 to 100 μm, it is preferably 10 to 50 μm, more preferably 10 to 30 μm, from the viewpoint of thinning the polarizing plate 100.

(7) Adhesive layer The 1st adhesive layer 31 is an adhesive layer arrange | positioned at the outermost surface of the polarizing plate 100, and attaches a polarizing plate with a protective film to an image display element (for example, liquid crystal cell) or another optical member. Can be used for pasting. The third pressure-sensitive adhesive layer 32 is used for bonding optical films constituting the polarizing plate 100 (for example, an optical film such as the brightness enhancement film 50 and the polarizer 10 or the protective film 21). The first pressure-sensitive adhesive layer 31 and the third pressure-sensitive adhesive layer 32 are pressure-sensitive adhesive compositions mainly composed of a resin such as (meth) acrylic, rubber-based, urethane-based, ester-based, silicone-based, or polyvinylether-based. Can be configured. Especially, the adhesive composition which uses (meth) acrylic resin excellent in transparency, weather resistance, heat resistance, etc. as a base polymer is suitable. The pressure-sensitive adhesive composition may be an active energy ray curable type or a thermosetting type.

  Examples of the (meth) acrylic resin (base polymer) used in the pressure-sensitive adhesive composition include butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, and (meth) acrylic acid 2- A polymer or copolymer having one or more (meth) acrylic acid esters such as ethylhexyl as a monomer is preferably used. The base polymer is preferably copolymerized with a polar monomer. Examples of polar monomers include (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, glycidyl ( Mention may be made of monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group and the like, such as (meth) acrylate.

  The pressure-sensitive adhesive composition may contain only the above base polymer, but usually further contains a crosslinking agent. As a crosslinking agent, a metal ion having a valence of 2 or more, which forms a carboxylic acid metal salt with a carboxyl group; a polyamine compound, which forms an amide bond with a carboxyl group; Examples thereof include epoxy compounds and polyols that form ester bonds with carboxyl groups; polyisocyanate compounds that form amide bonds with carboxyl groups. Of these, polyisocyanate compounds are preferred.

  The active energy ray-curable pressure-sensitive adhesive composition has a property of being cured by irradiation with active energy rays such as ultraviolet rays and electron beams, and has an adhesive property even before irradiation with active energy rays. It is a pressure-sensitive adhesive composition having such a property that it can be adhered to an adherend such as the like and can be cured by irradiation with active energy rays to adjust the adhesion. The active energy ray-curable pressure-sensitive adhesive composition is preferably ultraviolet curable. The active energy ray-curable pressure-sensitive adhesive composition further contains an active energy ray-polymerizable compound in addition to the base polymer and the crosslinking agent. Further, if necessary, a photopolymerization initiator, a photosensitizer and the like may be contained.

  Adhesive composition consists of fine particles for imparting light scattering properties, beads (resin beads, glass beads, etc.), glass fibers, resins other than base polymers, tackifiers, fillers (metal powder and other inorganic powders) Etc.), antioxidants, ultraviolet absorbers, dyes, pigments, colorants, antifoaming agents, corrosion inhibitors, photopolymerization initiators and the like.

  The 1st adhesive layer 31 and the 3rd adhesive layer 32 can be formed by apply | coating the organic solvent dilution liquid of the said adhesive composition on a base material, and making it dry. The substrate can be a polarizer 10, protective films 21, 22, other optical films such as a brightness enhancement film 50, a separate film (for example, a separate film 70), and the like. When the active energy ray-curable pressure-sensitive adhesive composition is used, a cured product having a desired degree of curing can be obtained by irradiating the formed pressure-sensitive adhesive layer with active energy rays.

  Although the thickness of the 1st adhesive layer 31 and the 3rd adhesive layer 32 can be 1-40 micrometers, the dimension change of the polarizing plate 100 is maintained, maintaining the viewpoint of thin film formation of the polarizing plate 100, and favorable workability. From the viewpoint of suppressing the thickness, it is preferably 3 to 25 μm (for example, 3 to 20 μm, more preferably 3 to 15 μm).

(8) Separate film The separate film 70 is a film that is temporarily attached to protect the surface of the first pressure-sensitive adhesive layer 31 until it is bonded to an image display element (for example, a liquid crystal cell) or another optical member. The separate film 70 is usually composed of a thermoplastic resin film that has been subjected to a release treatment on one side, and the release treatment surface is bonded to the first pressure-sensitive adhesive layer 31. The thermoplastic resin constituting the separate film 70 can be, for example, a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, a polyester resin such as polyethylene terephthalate or polyethylene naphthalate, and the like. In order to temporarily protect the surface of the third pressure-sensitive adhesive layer 32 until an optical film such as the brightness enhancement film 50 is pasted, a separate film similar to the above can be pasted. The thickness of the separate film 70 is, for example, 10 to 50 μm.

(9) Method for Producing Polarizing Plate with Protective Film In the method for producing a polarizing plate with a protective film according to the present invention, at least one end in a direction perpendicular to the laminating direction of at least one cross section in the laminating direction is the above ( Lamination is performed so as to satisfy any one of i) to (iii), or end face processing is performed after the lamination. An embodiment of a method for producing a polarizing plate with a protective film having a zigzag end face according to the present invention will be described. The manufacturing method of the polarizing plate with a protective film according to this embodiment includes the following steps:
[A] a first step of obtaining a polarizing plate by laminating the polarizing film (A) and the optical film (C);
[B] a second step of obtaining a film laminate by laminating a protective film on the polarizing plate obtained in the first step;
[C] A third step in which a plurality of film laminates obtained in the second step are stacked to obtain a polarizing plate laminate, and [d] rotation along the length direction of the end face of the obtained polarizing plate laminate. A fourth step of polishing at least one end face of the polarizing plate laminate by moving a polishing tool having a polishing blade, which rotates about an axis, relative to the polarizing plate laminate;
including. Hereinafter, each step will be described in detail.

[First step]
This step is a step of obtaining a polarizing plate by laminating at least the polarizing film (A) and the optical film (C). In this step, the end positions of the polarizing film (A) and the optical film (C) are adjusted, and lamination is performed so as to have an end that satisfies any of the above conditions (i) to (iii). Thus, when the second step is completed, the polarizing plate with a protective film according to the present invention can be obtained.

[Second step]
In this step, a protective film (D) is laminated on the polarizing plate obtained in the first step, and a polarizing film (A), an optical film (C), and a protective film (D) are laminated in this order. It is the process of obtaining the film laminated body.

[Third step]
This step is a step of obtaining a polarizing plate laminate by stacking a plurality of film laminates obtained in the second step where the end face is unpolished. The film laminate is square. The “square shape” is a square or a rectangle, and the size is not particularly limited. The number of film laminates to be stacked is not particularly limited. The film laminate used in this step is usually obtained by cutting a long film laminate.

  Referring to FIG. 7 for explaining a later-described fourth step of polishing the end face of the polarizing plate laminate, a polarizing plate laminate W obtained by stacking a plurality of film laminates has four exposures. Each end surface is constituted by an exposed end surface of each stacked film laminate. The plurality of film laminates are stacked so that their four sides are aligned. The stacking direction of the film laminates is not limited, and each film laminate may be set in the end face processing apparatus so that the protective film 60 is stacked on the upper side and the direction is maintained as it is. Then, the film laminates may be stacked on the end face processing apparatus so that the protective film 60 is stacked on the lower side and the direction is maintained as it is. The stacking of the film laminate can be performed automatically or manually.

[Fourth step]
In this step, the end face of the polarizing plate laminate obtained in the third step is polished with a polishing tool so as to satisfy any of the above relationships (i) to (iii), and a protective film having a polishing end face is attached. This is a step of obtaining a polarizing plate. FIG. 7: is a schematic perspective view for demonstrating an example of the 4th process which grind | polishes the polarizing plate laminated body end surface which concerns on this invention, and an end surface processing apparatus used for this process.

  With reference to FIG. 7, the end surface processing apparatus used for the grinding | polishing process of the polarizing plate laminated body end surface is demonstrated first. For example, as shown in FIG. 7, the end face processing apparatus presses the polarizing plate laminate W from above and below so that the polarizing plate laminate W itself does not move during the polishing process and the stacked polarizing plates are not displaced. The upper presser 420 and the lower presser 421 for fixing in such a manner that the lower presser 421 is supported, and the rotary table 431 that can rotate around the central axis parallel to the laminating direction z of the polarizing plate; A pressing tool 430 which is attached and can be rotated in the same direction as the rotary table 431; two polishing tools (polishing rotary bodies) 410 and 411 for polishing the end surface of the polarizing plate laminate W are provided. Can be things.

In the end face processing apparatus shown in FIG. 7, the polishing tools 410 and 411, which are disk-like rotating bodies provided with cutting blades protruding toward the end face of the laminate at the circumferential portion, are located at the positions of the polishing tools 410 and 411. In a fixed state, the polarizing plate laminate is rotated around a rotation axis extending along the perpendicular direction of the end face of the polarizing plate stack, and the polarizing plate stack is moved in the x direction to cut the end face of the stack. The moving speed of the polarizing plate laminate with respect to the polishing tools 410 and 411 can be set to 100 to 5000 mm / min, for example. The cutting amount of the end face of the polarizing plate laminate can be, for example, an average of 0.5 to 10 mm at each end face. The rotational speed of the polishing tools 410 and 411 can be set to, for example, 1000 to 10000 rpm.

  As shown in FIGS. 1 to 6, a film laminated body having a layer structure in which the uppermost surface is a protective film 60 and the lowermost surface is a separate film 70, the polished end surface is polished according to the rotation direction of the polishing tools 410 and 411. The cross-sectional shape may be different. For example, in the film laminated body, the polishing tools 410 and 411 are polished by rotating in the direction in which the blades are inserted in the order of the optical film 50, the polarizing film 20, and the separate film 70 in the order of the protective film 60. When the process is performed (hereinafter, also referred to as “protective film tip polishing”), as shown in FIG. 3, the angle of the end face with respect to the surface of the protective film 60 tends to become an obtuse angle. On the other hand, when the polishing tools 410 and 411 are rotated in the direction in which the blades are inserted in the order of the polarizing film 20, the optical film 50, and the protect film 60 and then subjected to the polishing process in the order in which the blades enter the separate film 70 first ( Hereinafter, the “protective film post-polishing”) tends to have an acute angle with respect to the surface of the protective film 60 as shown in FIG.

<LCD panel>
The liquid crystal panel according to the present invention includes a liquid crystal cell and the above-mentioned polarizing plate with a protective film according to the present invention laminated on the liquid crystal cell. In the liquid crystal panel, the polarizing plate with a protective film is arranged so that the first pressure-sensitive adhesive layer 31 is on the liquid crystal cell side (after peeling and removing the separate film 70 if it is provided). In the liquid crystal panel, a liquid crystal cell, a polarizing film (A), an adhesive layer (B), an optical film (C), and a protect film (D) are laminated in this order. The liquid crystal panel is used with the protective film 60 peeled off. The polarizing plate with a protective film of the present invention is preferably laminated on the back side of the liquid crystal cell.

FIGS. 8A and 8B are schematic views showing a method for peeling off the protective film. As shown in FIG. 8 (a), the protective film 60 is imparted with a force from the state in which the polarizing plate 110 with the protective film in which the polarizing plate 100 and the protective film 60 are laminated is bonded to the liquid crystal cell 200. Then, as shown in FIG. 8A, the protective film 60 is raised in the direction of arrow A to start peeling. Thereafter, an in-plane peeling force is applied to the protect film 60, and the protect film 60 is peeled in the direction of arrow B as shown in FIG.
The protective film 60 peeled off from the polarizing plate 100 is removed.

  In the peeling method shown in FIGS. 8 (a) and 8 (b), the application of force to the protective film 60 is performed by grasping an end portion (hereinafter also referred to as “peeling start end portion”) at which peeling of the protective film starts. You may carry out through the holding | grip of the peeling tape stuck on the area | region containing the peeling start edge part of a protection film, and this. Further, the application of force to the protection film 60 may be performed manually by an operator or may be performed automatically.

  The peeling start end of the protective film 60 satisfies any one of the above relationships (i) to (iii). When a force is applied to the protective film via the peeling tape, the peeling tape is stuck so as to protrude outward in a region including the peeling start end. 9 and 10 are top views schematically showing an example of the direction in which the release tape is applied on the surface of the protect film 60. FIG. The release tape 310 may be attached so as to include the peel start end portion of the protect film 60, and is attached to an area including the central portion of one end surface of the protect film 60 as shown in FIG. Even if it exists, as shown in FIG. 10, you may affix on the area | region containing the corner part of the protection film 60. FIG. As shown in FIG. 10, the direction of application to the region including one corner portion of the protective film 60 is peeled off as compared to the case of applying to the region including the central portion of one end surface of the protective film 60 as shown in FIG. Since it is easy to balance the time, the cause force and the in-plane peeling force tend to be further reduced. When the protective film 60 is peeled off, the protruding end portion of the peeling tape 310 is gripped directly or with a clip or the like, and the protective film 60 is peeled off by applying a force to the protective film. The release tape 310 may be attached to the protective film 60 before or after the polarizing plate 110 with the protective film is attached to the liquid crystal cell 200.

  The in-plane peeling force of the protective film 60 can also be adjusted by the peeling angle of the protective film 60. As shown in FIG. 11, the peeling angle of the protective film 60 means an angle θ formed by the protective film 60 and the polarizing plate 100 at the peeling portion. The peeling angle of the protective film 60 is preferably 0 ° or more and 90 ° or less, and more preferably 0 ° or more and 30 ° or less, since the in-plane peeling force can be within an appropriate range.

  In the present invention, when the peeling start end of the protective film 60 satisfies any of the above relationships (i) to (iii), the force required to cause the protective film can be reduced.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated further more concretely, this invention is not limited by these examples.

<Example 1>
(1) Production of Polarizer A polyvinyl alcohol film having an average degree of polymerization of about 2400 and a saponification degree of 99.9 mol% or more and a thickness of 20 μm was uniaxially stretched about 4 times in a dry manner and further kept in a tension state. After immersing in pure water of 1 ° C. for 1 minute, it was immersed in an aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.1 / 5/100 at 28 ° C. for 60 seconds. Thereafter, it was immersed in an aqueous solution having a weight ratio of potassium iodide / boric acid / water of 10.5 / 7.5 / 100 at 68 ° C. for 300 seconds. Subsequently, after washing with pure water at 5 ° C. for 5 seconds, drying was performed at 70 ° C. for 180 seconds to obtain a polarizer in which iodine was adsorbed and oriented on a uniaxially stretched polyvinyl alcohol film. The thickness of the polarizer was 7 μm.

(2) Preparation of water-based adhesive Polyvinyl alcohol powder [trade name “KL-318” manufactured by Kuraray Co., Ltd., average polymerization degree 1800] was dissolved in hot water at 95 ° C., and a polyvinyl alcohol aqueous solution having a concentration of 3% by weight was dissolved. Prepared. The resulting aqueous solution was mixed with a crosslinking agent [trade name “Smiles Resin 650” manufactured by Taoka Chemical Industry Co., Ltd.] at a ratio of 1 part by weight to 2 parts by weight of polyvinyl alcohol powder to obtain an aqueous adhesive. .

(3) Production of single-sided protective polarizing plate A single-sided protective polarizing plate with a release film was produced by the following procedure.

While continuously transporting the polarizer obtained in the above ( 1 ), the protective film is continuously unwound from a roll of a protective film [acrylic resin film, manufactured by Sumitomo Chemical Co., Ltd., thickness 20 μm] and subjected to corona treatment. The release film was continuously unwound from a roll of release film [trade name “KC8UX2MW”, TAC film manufactured by Konica Minolta Opto Co., Ltd., thickness 80 μm, no saponification treatment].

  Next, the water-based adhesive obtained in (2) above is injected between the polarizer and the protective film, and pure water is injected between the polarizer and the release film, and passed between the bonding rolls for protection. A laminated film consisting of film / water-based adhesive layer / polarizer / pure water / release film was obtained. Subsequently, the laminated film is transported and subjected to a heat treatment at 80 ° C. for 300 seconds through a drying apparatus to volatilize and remove pure water intervening between the polarizer and the release film as well as drying the aqueous adhesive layer. Thus, a single-sided protective polarizing plate with a release film was obtained. The release film was peeled from the single-side protective polarizing plate with release film to obtain a single-side protective polarizing plate (polarizing film).

(4) Production of single-sided protective polarizing plate with brightness enhancement film Acrylic pressure-sensitive adhesive sheet [manufactured by Lintec Corporation, thickness 15 μm, storage at 20 ° C. on the polarizer surface of the single-sided protective polarizing plate obtained in (3) above. Via an elastic modulus of 0.031 MPa, the brightness enhancement film (trade name “APF”, which is a reflective polarizer manufactured by 3M Co., Ltd.) is parallel to the extension direction of the polarizer and the extension axis of the reflective polarizer is parallel to the extension direction. Then, a single-side protective polarizing plate with a brightness enhancement film was obtained.

(5) Production of single-sided protective polarizing plate with separate film Acrylic pressure-sensitive adhesive sheet with a separate film on the protective film surface of the single-sided protective polarizing plate with the brightness enhancement film obtained in (4) above [manufactured by Lintec Corporation, adhesive The thickness of the agent layer was 20 μm] to obtain a single-side protective polarizing plate with a separate film.

(6) Production of polarizing plate with protective film A protective film [manufactured by Fujimori Kogyo Co., Ltd., thickness 58 μm] is bonded to the brightness enhancement film side to the single-sided protective polarizing plate with a separate film obtained in (5) above. A polarizing plate with a protective film was obtained.

(7) Polishing process Cutting the long polarizing plate with protective film obtained in (6) above with a super cutter (manufactured by Hadano Seiki Co., Ltd., cutting with a blade descending from the top of the film) A polarizing plate with a protective film having a shape is formed, and the four end surfaces thereof are polished using the polishing apparatus shown in FIG. 7, and the clamping pressure between the upper presser 420 and the lower presser 421 shown in FIG. Polishing was performed by polishing. The edge part of the polarizing plate with a protective film obtained after the polishing process was typically shaped as shown in FIG. 3 (the relative thickness of each layer does not match that in FIG. 3). The outermost position P1 in the width direction of the polarizing film 20 and the outermost position P2 in the width direction of the brightness enhancement film 50 satisfy the relationship (i) above, and the distance in the width direction between the position P1 and the position P2 L was 3 μm. The polarizing plate with a protective film had a rectangular shape, and the maximum length of the short side was 6 cm and the maximum length of the long side was 21.6 cm. The distance L in the width direction between the position P1 and the position P2 was measured using a LEXT (registered trademark) OLS4100 manufactured by Olympus Corporation. Specifically, the distance L was measured in a non-contact manner by laser scanning the end face of the polarizing plate with a protective film.

<Example 2>
In the above (3), the same method as in Example 1 except that a cycloolefin polymer film (COP) [trade name: ZF-14, manufactured by Nippon Zeon Co., Ltd., thickness 13 μm] was used as the protective film. A polarizing plate with a protective film (6) was obtained.

  Polishing was performed in the same manner as in Example 1 except that in (7) above, polishing was performed by post-protection film polishing with a clamp pressure of 0.1 MPa. The edge part of the polarizing plate with a protective film obtained after the polishing process was typically shaped as shown in FIG. 4 (the relative thickness of each layer does not match that in FIG. 4). The outermost position P1 in the width direction of the polarizing film 20 and the outermost position P2 in the width direction of the brightness enhancement film 50 satisfy the relationship (i) above, and the distance in the width direction between the position P1 and the position P2 L was 5.5 μm. The polarizing plate with a protective film had a rectangular shape, and the maximum length of the short side was 6 cm and the maximum length of the long side was 11 cm.

<Example 3>
A polarizing plate with a protective film was obtained in the same manner as in Example 2 except that the polishing process (7) was not performed. The edge part of the obtained polarizing plate with a protective film typically had a shape as shown in FIG. 1 (the relative thickness of each layer does not match that in FIG. 1). The outermost position P1 in the width direction of the polarizing film 20 and the outermost position P2 in the width direction of the brightness enhancement film 50 satisfy the relationship (iii) above, and the distance in the width direction between the position P1 and the position P2 L was less than 1 μm. The polarizing plate with a protective film had a rectangular shape, and the maximum length of the short side was 6 cm and the maximum length of the long side was 11 cm.

<Comparative Example 1>
In the above (4), the brightness-enhancing film is bonded to the protective film surface of the single-sided polarizing plate to produce a single-sided polarizing plate with the brightness-enhancing film. In the above (5), an acrylic pressure-sensitive adhesive sheet with a separate film. A polarizing plate with a protective film of (6) above was obtained in the same manner as in Example 1, except that was bonded to the polarizer surface of the single-side protective polarizing plate with a brightness enhancement film.

  Polishing was performed in the same manner as in Example 1 except that in the above (7), the clamp pressure was 0.1 MP. The edge part of the polarizing plate with a protective film obtained after the polishing process was typically shaped as shown in FIG. 12 (the relative thickness of each layer does not match that in FIG. 12). The outermost position P1 in the width direction of the polarizing film 20 is inside the outermost position P2 in the width direction of the brightness enhancement film 50, and the distance L in the width direction between the position P1 and the position P2 is 3.5 μm. Yes, and none of the above relationships (i) to (iii) was satisfied. The polarizing plate with a protective film had a rectangular shape, and the maximum length of the short side was 6 cm and the maximum length of the long side was 11 cm.

<Comparative Example 2>
In the above (7), a polarizing plate with a protective film was obtained in the same manner as in Example 2 except that the clamp pressure was 0.05 MPa. The edge part of the obtained polarizing plate with a protective film typically had a shape as shown in FIG. 13 (the relative thickness of each layer does not match that in FIG. 13). The outermost position P1 in the width direction of the polarizing film 20 is inside the outermost position P2 in the brightness enhancement film 50, and the distance L in the width direction between the position P1 and the position P2 is 2 μm. ) To (iii) none of the relationships was satisfied. The polarizing plate with a protective film had a rectangular shape, and the maximum length of the short side was 6 cm and the maximum length of the long side was 11 cm.

<Comparative Example 3>
In the above (7), a polarizing plate with a protective film was obtained in the same manner as in Example 2 except that the polishing was performed by protective film tip polishing. The end of the cross section at the center of the short side of the obtained polarizing plate with a protective film typically had a shape as shown in FIG. 14 (the relative thickness of each layer does not match that in FIG. 14). The outermost position P1 in the width direction of the polarizing film 20 is inside the outermost position P2 of the brightness enhancement film 50, and the distance L in the width direction between the position P1 and the position P2 is 5 μm. ) To (iii) none of the relationships was satisfied. The polarizing plate with a protective film had a rectangular shape, and the maximum length of the short side was 6 cm and the maximum length of the long side was 11 cm.

[Evaluation Test 1]
Using the polarizing plates with protective film of Examples 1 to 3 and Comparative Examples 1 to 3, an evaluation test for confirming the peelability of the protective film was performed. FIG. 15 is a diagram schematically showing the method of this evaluation test. In this evaluation test, first, the polarizing plate 110 with a protective film was peeled off from the separate film 70 on the lowermost surface, and bonded to the glass plate 330 through the adhesive layer 31 to produce an evaluation sample. Then, on the surface of the protective film, the peeling tape 310 (product) includes this position and the end protrudes outward so that the position where the distance L is measured (the center of the short side) is the peeling start point. Name: Nitto No. 31B, width 25 mm) was affixed. The release tape 310 was attached so that the length of the part attached to the protective film was about 3 cm and the length of the protruding part was about 3 cm. Then, the portion of the peeling tape 310 that protrudes outward was gripped by the clip 320 so as to have an angle of about 90 ° (peeling angle) with respect to the surface direction. The gripping position of the clip 320 was a position approximately 2 cm from the surface of the protective film. Then, without moving the clip, the protective film was peeled off by moving the glass plate 330 on which the polarizing plate was bonded in the surface direction at a speed of 1.2 m / min. The force required to peel off the protective film at this time was measured with a load cell. The measured value at the start of peeling was the force, and the subsequent measured value was defined as the in-plane peeling force. Table 1 shows the measurement results.

  From the results shown in Table 1, the polarizing plates with protective film of Examples 1 to 3 are less prone to the protective film than the polarizing plates with protective film of Comparative Examples 1 and 2, and are excellent in the peelability of the protective film. It was a thing. The protective film-attached polarizing plate of Comparative Example 3 could not peel off the protective film.

[Evaluation Test 2]
Samples for evaluation were prepared in the same manner as in Evaluation Test 1 using the polarizing plates with protective films of Examples 1 to 3 and Comparative Examples 1 to 3. Instead of the release tape used in Evaluation Test 1, a release tape (trade name: Cello Tape (registered trademark), manufactured by Nichiban Co., Ltd., width 24 mm) is used to hold the clip so that the release angle is approximately 180 °. With the glass plate 330 fixed so as not to move, the clip was moved at a speed of 1.0 m / min to peel off the protective film. The polarizing plates with a protective film of Examples 1 to 3 were able to peel off the protective film, but the polarizing plates with a protective film of Comparative Examples 1 to 3 were peeled off from the surface of the protective film and peeled off the protective film. I couldn't.

  DESCRIPTION OF SYMBOLS 10 Polarizer, 20 Polarizing film, 21, 22 Protective film, 31 1st adhesive layer, 32 3rd adhesive layer, 50 Brightness improvement film, 60 Protective film, 61 Base film, 62 2nd adhesive layer, 70 Separate film, 100 Polarizing plate, 110, 111, 112, 113, 114 Polarizing plate with protective film, 200 Liquid crystal cell, 310 Peeling tape, 320 Clip, 330 Glass plate, 410,411 Polishing tool, 420 Upper presser, 421 Lower presser, 431 rotary table.

Claims (8)

A polarizing plate having a polarizing film, an adhesive layer, and an optical film;
A protective film composed of a base film and a second pressure-sensitive adhesive layer, which is laminated on the surface of the polarizing plate and peeled off ;
The polarizing film, the pressure-sensitive adhesive layer, the optical film, the protective film is a polarizing plate with a protective film in which the protective film is laminated in this order,
At least one cross section in the laminating direction has an outermost position P1 of the polarizing film in the direction perpendicular to the laminating direction at at least one end in the direction orthogonal to the laminating direction, and the outermost position of the optical film. The outer position P2 is the following (i ):
(I) Ri outer der the position P1 is the position P2, and the distance position P1 and the position P2 is 2μm or more 20μm or less,
A polarizing plate with a protective film that satisfies this relationship. The polarizing plate with a protective film according to claim 1, wherein the polarizing film includes a polarizer and a protective film. The pressure-sensitive adhesive layer has a storage elastic modulus at a temperature 20 ° C. is 0.1MPa or less, the protective film with the polarizing plate according to claim 1 or 2. The said edge part is a polarizing plate with a protective film of any one of Claims 1-3 which exists in a grinding | polishing end surface. The polarizing plate with a protective film according to claim 4 , wherein the polished end surface has a shape in which V-shaped grooves and pointed portions are alternately formed. A liquid crystal cell, and a polarizing plate with a protective film according to any one of claims 1 to 5 ,
The liquid crystal panel in which the liquid crystal cell, the polarizing film, the pressure-sensitive adhesive layer, the optical film, and the protective film are laminated in this order. Polarizing film, an adhesive layer, and obtaining the optical film, the peeling is removed, the film laminate protective film consisting of a base film with a second adhesive layer are laminated in this order,
In at least one end face of the film laminate, the outermost position P1 of the polarizing film and the outermost position P2 of the optical film with respect to the direction orthogonal to the laminating direction are the following (i):
(I) Ri outer der the position P1 is the position P2, and the distance position P1 and the position P2 is 2μm or more 20μm or less,
And a step of obtaining a polarizing plate with a protective film by polishing so as to satisfy the above relationship. The said adhesive layer is a manufacturing method of the polarizing plate with a protective film of Claim 7 whose storage elastic modulus in temperature 20 degreeC is 0.1 Mpa or less.