JP2022182000A - Method for manufacturing polarizer piece - Google Patents

Abstract

To provide a method for manufacturing a polarizer piece, capable of preventing a dent from being generated in a polarizer to manufacture the polarizer piece excellent in appearance.SOLUTION: A method for manufacturing a polarizer piece comprises the steps of: bonding a long-sized surface protection film having a plurality of first through holes to a long-sized polarizer to form a laminate; subjecting parts of the polarizer exposed from the plurality of first through holes to decolorization to form a plurality of non-polarization parts; winding the laminate including the polarizer having the plurality of non-polarization parts in a roll state; and cutting a plurality of polarizer pieces including the non-polarization part from the polarizer. The surface protection film includes a second through hole positioned between a first through hole positioned at one end in the width direction in the plurality of first through holes and one end edge of the surface protection film in the width direction.SELECTED DRAWING: Figure 5

Description

The present invention relates to a method for manufacturing a polarizer piece.

In recent years, due to the rapid spread of smart phones and touch panel type information processing devices, there is a demand for further improvements in camera performance and the like. In addition, a polarizing plate having partial polarizing performance is required in order to cope with the diversification of the shape and high functionality of image display devices. As such a polarizing plate, a polarizer having a non-polarizing portion formed by chemical treatment is known.
As a method for producing a polarizing plate having a non-polarizing portion, after bonding a surface protective film having a plurality of through holes to a long polarizer intermediate, chemically decolorize the portion of the polarizer intermediate exposed through the through holes. A non-polarizing portion is formed by treatment, and then the laminate including the structure of the surface protective film/polarizer intermediate is wound into a roll, and then a plurality of polarizers including the non-polarizing portion are cut from the polarizer intermediate. is proposed (for example, Patent Document 1). However, when a laminate including a surface protective film having a plurality of through-holes is wound into a roll, dents (hole marks) may occur in the polarizer intermediate due to tight winding.

JP 2018-31954 A

The present invention has been made to solve the above-described conventional problems, and a main object thereof is to provide a polarizer even when a laminate including a surface protective film having a plurality of first through holes is wound into a roll. It is an object of the present invention to provide a method for manufacturing a polarizer piece which can suppress the occurrence of dents and which can manufacture a polarizer piece having an excellent appearance.

A method for manufacturing a polarizer piece according to an embodiment of the present invention provides a surface protective film having a long shape, and a plurality of first first surfaces arranged at intervals in a width direction orthogonal to a long direction of the surface protective film. A step of bonding a surface protective film having through holes to a long polarizer having a dichroic substance to form a laminate, and a portion of the polarizer exposed from the plurality of first through holes, Decolorizing through the first through holes to form a plurality of non-polarizing portions on the polarizer; and Winding into a roll a laminate including the polarizer on which the plurality of non-polarizing portions are formed. and a step of cutting out a plurality of polarizer pieces each including the non-polarizing portion from the polarizer after the winding, wherein the surface protective film cuts out from the polarizer at one end in the width direction of the plurality of first through holes. and a second through hole positioned between one edge in the width direction of the surface protection film.
In one embodiment, the opening areas of the plurality of first through holes are substantially the same, and the opening area of the second through holes is different from the opening area of each of the first through holes. is 0.5 or more.
In one embodiment, the opening areas of the plurality of first through holes are substantially the same, and the opening area of the second through holes is different from the opening area of each of the first through holes. is less than 0.5, and a plurality of the second through holes are arranged at intervals in the longitudinal direction.
In one embodiment, the surface protection film includes a first through hole positioned at the other end in the width direction among the plurality of first through holes, and the other edge in the width direction of the surface protection film. It further has a third through hole located between.
In one embodiment, the gap in the width direction between the first through hole and the second through hole located at one end in the width direction, and the second through hole and one end of the surface protection film Each of the widthwise intervals between edges is equal to or less than the widthwise interval between adjacent first through holes among the plurality of first through holes.

According to the embodiment of the present invention, it is possible to suppress the occurrence of dents on the polarizer due to the local increase in the roll hardness (roll internal stress) of the laminate wound into a roll, and the polarization excellent in appearance. Can produce offal pieces.

1 is a schematic diagram showing one embodiment of a method for manufacturing a polarizer piece of the present invention; FIG. FIG. 2 is a schematic perspective view of the first surface protection film of FIG. 1; FIG. 2 is a schematic cross-sectional view in a direction parallel to the width direction of the laminate of FIG. 1; FIG. 4 is a schematic cross-sectional view showing a state in which the first surface protection film is removed from the laminate of FIG. 3; FIG. 4 is an enlarged plan view of a main part of the laminate of FIG. 3; FIG. 4 is an enlarged plan view of a main part of a laminate according to another embodiment of the present invention; FIG. 6 is an enlarged plan view of a main part of a laminate according to still another embodiment of the present invention; FIG. 6 is an enlarged plan view of a main part of a laminate according to still another embodiment of the present invention; FIG. 6 is an enlarged plan view of a main part of a laminate according to still another embodiment of the present invention; FIG. 6 is an enlarged plan view of a main part of a laminate according to still another embodiment of the present invention; FIG. 4 is an enlarged plan view of a main part of a laminate according to a comparative example of the invention; FIG. 5 is an enlarged plan view of a main part of a laminate according to another comparative example of the invention;

Although representative embodiments of the present invention will be described below, the present invention is not limited to these embodiments.

A. Outline of method for producing polarizer piece FIG. 1 is a schematic diagram showing one embodiment of the method for producing a polarizer piece of the present invention; FIG. 2 is a schematic perspective view of the surface protective film of FIG. 1; 3 is a schematic cross-sectional view in a direction parallel to the width direction of the laminate of FIG. 1; FIG. 4 is a schematic cross-sectional view of a state in which the first surface protective film is removed from the laminate of FIG. 3; 5 is an enlarged plan view of a main part of the laminate of FIG. 3. FIG.

In the manufacturing method of the polarizer piece of the illustrated example, a long surface protective film 1 having a plurality of first through holes 1a is attached to a long polarizer 21 having a dichroic substance to form a laminate. 4 (laminated body forming step); the portion of the polarizer 21 exposed from the plurality of first through holes 1a is decolorized through the first through holes 1a, and the polarizer 21 has a plurality of non- A step of forming the polarizing portion 21a (polarizer decolorization treatment step); ); and a step of cutting out a plurality of polarizer pieces 210 each including the non-polarizing portion 21a from the polarizer 21 after winding (a step of cutting out the polarizer pieces). The surface protective film 1 has one end edge E1 and the other end edge E2 in the width direction perpendicular to the longitudinal direction. The plurality of first through holes 1a are arranged at intervals in the width direction of the surface protective film 1 . The surface protection film 1 has a first through hole 1a positioned at one end in the width direction of the plurality of first through holes 1a and a second through hole positioned between one end edge E1 in the width direction of the surface protection film 1. It further has 1b. After bonding a surface protective film having a plurality of through holes to a polarizer, when the obtained laminate is wound into a roll, the roll hardness (roll internal stress) of the laminate locally decreases due to tight winding. may be higher. In particular, the roll internal stress tends to concentrate at the ends of the roll of the laminate, and the hardness tends to be high. In this case, there is a possibility that the polarizer may be dented at a portion (specifically, an end portion, etc.) where stress is concentrated in the roll of the laminate. On the other hand, according to the above-described method, the surface protection film 1 has the first through holes 1a located at one end in the width direction and the surface protection film 1 in addition to the plurality of first through holes 1a used for the decolorization treatment. 1 and the second through hole 1b located between one end edge E1 of the laminate 4, it is possible to suppress the concentration of the roll internal stress on one end of the roll 5 of the laminate 4, and the roll 5 of the laminate 4 can be suppressed. It is possible to suppress the local increase in the hardness (internal stress of the roll). In other words, it is possible to improve the uniformity of hardness (roll internal stress) in the roll 5 . As a result, it is possible to suppress the occurrence of dents on the polarizer 21 included in the roll 5 of the laminate 4, and a plurality of polarizer pieces 210 having a non-polarizing portion 21a and having an excellent appearance can be obtained from the polarizer 21. can be cut out.

The widthwise dimension of the laminate 4 is typically 500 mm to 2000 mm, preferably 1000 mm to 1500 mm.
The shape of the first through hole 1a in plan view can be appropriately changed according to the shape required for the non-polarizing portion 21a. Examples of the planar shape of the first through hole 1a include a circle, an oval, a square, a rectangle, a rhombus, and the like, preferably a circle. A plan view shape of the second through hole 1b is not particularly limited. Examples of the shape of the second through-hole 1b in plan view include circular, elliptical, square, rectangular, rhombic, and the like, preferably circular.

In one embodiment of the present invention, in the step of cutting out polarizer pieces, a plurality of one type of polarizer pieces 210 having substantially the same configuration are cut out from one sheet of polarizer 21 film. In this embodiment, the plurality of first through holes 1a of the surface protection film 1 are arranged at substantially equal intervals in the width direction, and the opening area of each of the plurality of first through holes 1a is substantially essentially identical to each other. In the step of cutting out the polarizer pieces, a plurality of two or more types of polarizer pieces 210 having substantially different configurations may be cut out from one film of the polarizer 21 . In this case, the plurality of first through holes 1a may be arranged at different intervals in the width direction, and the opening areas of the plurality of first through holes 1a may be different from each other.

In one embodiment of the present invention, the surface protection film 1 has rows 1A of a plurality of first through holes 1a arranged at substantially equal intervals in the width direction of the surface protection film 1. It has a plurality of them spaced apart in the direction. In this case, in the step of performing the decolorization treatment through the polarizer 21, a row composed of a plurality of non-polarizing portions 21a arranged at equal intervals in the width direction is arranged in the longitudinal direction of the polarizer 21. A plurality of them can be formed at intervals. Therefore, it is possible to increase the number of polarizer pieces 210 that can be cut out from the elongated polarizer 21, and to improve the manufacturing efficiency of the polarizer pieces 210. FIG. The longitudinal spacing between adjacent rows 1A is typically 10 mm to 500 mm, preferably 20 mm to 400 mm.

One second through hole 1b may be provided for one row 1A, or a plurality of second through holes 1b may be provided for one row 1A. In the case where one second through hole 1b is provided for one row 1A, the second through hole 1b has the width of the plurality of first through holes 1a included in the row 1A, as shown in FIGS. It may be positioned so as to overlap with the imaginary line passing collectively in the direction, or may be displaced from the imaginary line in the longitudinal direction as shown in FIG. 8 .

When one second through hole 1b is provided for one row 1A, the opening area of the second through hole 1b is preferably 0.1 or more with respect to the opening area of each first through hole 1a, for example. is 0.5 or more, more preferably 1.0 or more, still more preferably 1.5 or more, for example, 5.0 or less, preferably 3.0 or less. The opening area of the through-hole (the first through-hole 1a or the second through-hole 1b) is the area of the through-hole in the cross section of the surface protective film 1 cut in the plane direction orthogonal to the thickness direction. The opening area of the second through-hole 1b for each first through-hole 1a (the opening area of one second through-hole 1b/the opening area of one first through-hole 1a; hereinafter, the opening area ratio of the second through-hole 1b and ) is at least the above lower limit, particularly at least 0.5, it is possible to stably suppress a local increase in the hardness (internal stress of the roll) of the roll 5 of the laminate 4 . When the opening area ratio of the second through-holes 1b is equal to or less than the above upper limit, the space for providing the second through-holes 1b in the surface protective film 1 can be reduced, and the product of the polarizer 21 (the polarizer piece 210) can be reduced. The outer margin portion can be made smaller.

Further, as shown in FIG. 9, when a plurality of second through holes 1b are provided for one row 1A, even if the opening area ratio of the second through holes 1b is less than 0.5, the laminate Local increase in the hardness (roll internal stress) of the roll 5 of 4 can be stably suppressed. The plurality of second through holes 1b are arranged at intervals in the longitudinal direction of the surface protective film 1 . The number of second through holes 1b provided for one row 1A is, for example, 2-10, preferably 2-8. In this case, the opening area ratio of the second through holes 1b is preferably less than 0.5, more preferably 0.3 or less, still more preferably 0.2 or less, for example 0.01 or more, preferably is 0.5 or less. If the opening area ratio of the second through holes 1b is within the above range, the hardness (roll internal stress) of the roll 5 of the laminate 4 is locally increased while the margin portion of the polarizer 21 outside the product can be made smaller. can be stably suppressed.

In one embodiment of the present invention, the widthwise interval L2 between the first through hole 1a located at one end in the width direction of the plurality of first through holes 1a and the second through hole 1b, and the Each of the widthwise intervals L3 between the two through holes 1b and one edge E1 of the surface protection film 1 is the widthwise interval between the first through holes 1a adjacent to each other among the plurality of first through holes 1a. L1 or less. A widthwise distance L1 between the first through holes 1a adjacent to each other is typically 10 mm to 400 mm, preferably 20 mm to 300 mm. An interval L4 between the first through-hole 1a positioned at one end in the width direction of the plurality of first through-holes 1a and one edge E1 of the surface protection film 1 is equal to or larger than the interval L1 between the adjacent first through-holes 1a. , the positional balance of the plurality of first through holes 1a is poor, and the uniformity of the positions of the plurality of first through holes 1a is reduced. Therefore, roll internal stress tends to concentrate on one end of the roll 5 of the laminate 4 . On the other hand, when the second through holes 1b are provided so as to satisfy the intervals L2 and L3, the plurality of first through holes 1a and the second through holes 1b are arranged in a well-balanced manner. Concentration of roll internal stress on one end of the roll 5 of 4 can be stably suppressed.

In one embodiment of the present invention, as shown in FIGS. 8 and 10, the surface protective film 1 includes a first through hole 1a positioned at the other end in the width direction among the plurality of first through holes 1a, It further has a third through hole 1c located between the other widthwise edge E2 of the surface protection film 1 and the third through hole 1c. When the surface protection film 1 has the third through-holes 1c, it is possible to suppress the concentration of the roll internal stress on the other end of the roll 5 of the laminate 4, and the hardness (roll internal stress) of the roll 5 of the laminate 4 increases. Local heightening can be suppressed more stably. When the surface protection film 1 has a plurality of rows 1A of the first through holes 1a spaced apart in the longitudinal direction, the third through holes 1c are arranged in one row 1A in the same manner as the second through holes 1b. One row may be provided for one row 1A, or a plurality of rows may be provided for one row 1A.

The details of the method for manufacturing the polarizer piece will be described below with reference to FIGS. 1 to 5. FIG.
In one embodiment of the present invention, the surface protective film 1 is attached to the polarizing plate 2 including the polarizer 21 and the protective layer 22 to form the laminate 4 (laminate formation step), and then the polarizer 21 is partially decolorized to form a plurality of non-polarizing portions 21a (polarizer decolorization treatment step), and after winding the laminate 4 into a roll (laminate winding step), the polarizer 21 A plurality of polarizing plate pieces 20 each including a polarizer piece 210 including a non-polarizing portion 21a are cut out from the substrate (step of cutting out polarizing plate pieces). In this embodiment, the polarizing plate 2 having the protective layer 22 attached in advance to the polarizer 21 is prepared, but the timing of providing the protective layer 22 is not particularly limited. The surface protective film 1 is attached to the polarizer 21 to which the protective layer 22 is not attached, and the protective layer 22 is attached to the polarizer 21 after partial decolorization of the polarizer 21 and before winding the laminate 4. Alternatively, the protective layer 22 may be attached to the polarizer 21 after the laminate 4 is wound and before the polarizing plate pieces 20 are cut out. A piece of protective layer 220 may be applied to 210 .

B. Step of Forming Laminate In the step of forming the laminate, more specifically, after the second surface protective film 3 is laminated to the protective layer 22 provided in the polarizing plate 2 by roll-to-roll, the surface protective film 1 described above is applied. is attached to the polarizer 21 included in the polarizing plate 2 by roll-to-roll to form the laminate 4 . “Roll-to-roll” refers to laminating roll-shaped films while aligning their longitudinal directions while conveying them. In the following, the surface protection film 1 is distinguished from the second surface protection film 3 as the first surface protection film 1 . By bonding the second surface protective film 3 to the polarizing plate 2 before the first surface protective film 1, the first through holes 1a of the first surface protective film 1 are transferred to the polarizer 21 as dents. can be suppressed.

The laminate 4 has a laminated structure of first surface protective film 1 /polarizer 21 /protective layer 22 /second surface protective film 3 . In addition, after bonding the first surface protective film 1 to the polarizer 21, the second surface protective film 3 can also be bonded to the protective layer 22, without using the second surface protective film 3. 1 of the surface protective film 1 can also be attached to the polarizer 21 .

B-1. Polarizing Plate The polarizing plate 2 has an elongated shape and can typically be wound into a roll. The polarizing plate 2 includes a polarizer 21 and a protective layer 22 bonded via any suitable adhesive layer (adhesive layer, adhesive layer: not shown).

B-1-1. Polarizer Any appropriate polarizer can be employed as the polarizer 21 . For example, the resin film forming the polarizer 21 may be a single-layer resin film or a laminate of two or more layers. A resin film forming the polarizer 21 contains a dichroic substance. Dichroic substances include, for example, iodine and organic dyes. Dichroic substances can be used alone or in combination. Among the dichroic substances, iodine is preferred. For example, when the non-polarizing portion 21a is formed by chemical decolorization, the iodine complex contained in the polarizer 21 can be appropriately reduced, and the non-polarizing portion 21a can be provided with properties suitable for use in the camera section, for example. be.

A specific example of a polarizer composed of a single-layer resin film is a PVA-based resin film that has been dyed with iodine and stretched (typically, uniaxially stretched). The dyeing with iodine is performed by, for example, immersing the PVA-based film in an aqueous iodine solution. The draw ratio of the uniaxial drawing is preferably 3 to 7 times. Stretching may be performed after the dyeing treatment, or may be performed while dyeing. Moreover, you may dye after extending|stretching. If necessary, the PVA-based resin film is subjected to swelling treatment, cross-linking treatment, washing treatment, drying treatment, and the like. For example, by immersing the PVA-based resin film in water and washing it with water before dyeing, it is possible not only to wash away stains and anti-blocking agents on the surface of the PVA-based film, but also to swell the PVA-based resin film to prevent uneven dyeing. etc. can be prevented.

Specific examples of the polarizer obtained using a laminate include a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a resin substrate and the resin A polarizer obtained by using a laminate with a PVA-based resin layer formed by coating on a substrate can be mentioned. A polarizer obtained by using a laminate of a resin base material and a PVA-based resin layer formed by coating on the resin base material is obtained, for example, by applying a PVA-based resin solution to the resin base material and drying the resin base material. forming a PVA-based resin layer thereon to obtain a laminate of a resin substrate and a PVA-based resin layer; stretching and dyeing the laminate to use the PVA-based resin layer as a polarizer; obtain. In one embodiment of the present invention, preferably, a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin is formed on one side of the resin substrate. Stretching typically includes immersing the laminate in an aqueous boric acid solution for stretching. Furthermore, stretching may further include stretching the laminate in air at a high temperature (eg, 95° C. or higher) before stretching in an aqueous boric acid solution, if necessary. In addition, in one embodiment of the present invention, the laminate is preferably subjected to drying shrinkage treatment to shrink the laminate by 2% or more in the width direction by heating while conveying in the longitudinal direction. Typically, the manufacturing method of the present embodiment includes subjecting the laminate to an in-air auxiliary stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment in this order. By introducing auxiliary stretching, it is possible to improve the crystallinity of PVA and achieve high optical properties even when PVA is coated on a thermoplastic resin. At the same time, by increasing the orientation of PVA in advance, it is possible to prevent problems such as deterioration of orientation and dissolution of PVA when immersed in water in the subsequent dyeing process or stretching process, resulting in high optical properties. can be achieved. Furthermore, when the PVA-based resin layer is immersed in a liquid, disturbance of the orientation of the polyvinyl alcohol molecules and deterioration of the orientation can be suppressed as compared with the case where the PVA-based resin layer does not contain a halide. This can improve the optical properties of the polarizer obtained through treatment steps such as dyeing treatment and underwater stretching treatment in which the laminate is immersed in a liquid. Furthermore, the optical properties can be improved by shrinking the laminate in the width direction by drying shrinkage treatment. The obtained resin substrate/polarizer laminate may be used as it is (that is, the resin substrate may be used as a protective layer for the polarizer), or the resin substrate may be peeled off from the resin substrate/polarizer laminate. Then, any appropriate protective layer may be laminated on the release surface according to the purpose. Details of the method for manufacturing such a polarizer are described in, for example, Japanese Patent Application Laid-Open No. 2012-73580 and Japanese Patent No. 6470455. These publications are incorporated herein by reference in their entireties.

The polarizer 21 is preferably composed of a laminate of two or more layers, and more preferably composed of a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate.

The thickness of the polarizer 21 is preferably 15 μm or less, more preferably 12 μm or less, still more preferably 10 μm or less, particularly preferably 8 μm or less, and typically 1 μm or more, preferably 3 μm or more.

The polarizer 21 preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The single transmittance of the polarizer 21 is, for example, 41.5% to 46.0%, preferably 43.0% to 46.0%, more preferably 44.5% to 46.0%. . The degree of polarization of the polarizer 21 is preferably 97.0% or higher, more preferably 99.0% or higher, still more preferably 99.9% or higher.

B-1-2. Protective Layer Protective layer 22 is formed of any suitable film that can be used as a protective layer for polarizer 21 . Specific examples of the material that is the main component of the film include cellulose-based resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, and polysulfone-based resins. , polystyrene-based, polynorbornene-based, polyolefin-based, (meth)acrylic-based, and acetate-based transparent resins. Thermosetting resins such as (meth)acrylic, urethane, (meth)acrylic urethane, epoxy, and silicone, or ultraviolet curable resins may also be used. In addition, "(meth)acrylic resin" refers to acrylic resin and/or methacrylic resin. In addition, for example, a glassy polymer such as a siloxane-based polymer can also be used. Further, polymer films described in JP-A-2001-343529 (WO01/37007) can also be used. Materials for this film include, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in a side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and nitrile group in a side chain. can be used, for example, a resin composition comprising an alternating copolymer of isobutene and N-methylmaleimide and an acrylonitrile/styrene copolymer. The polymer film can be, for example, an extrudate of the resin composition.

The protective layer 22 preferably contains a (meth)acrylic resin. As the (meth)acrylic resin, for example, a (meth)acrylic resin having a glutarimide structure is used. (Meth)acrylic resins having a glutarimide structure, for example, JP-A-2006-309033, JP-A-2006-317560, JP-A-2006-328329, JP-A-2006-328334, JP-A-2006 -337491, JP 2006-337492, JP 2006-337493, JP 2006-337569, JP 2007-009182, JP 2009-161744, JP 2010-284840 It is described in the publication. These descriptions are incorporated herein by reference.

The thickness of the protective layer 22 is typically 300 μm or less, preferably 100 μm or less, more preferably 5 μm to 80 μm, still more preferably 10 μm to 60 μm. In addition, when the surface treatment is performed, the thickness of the protective layer 22 is the thickness including the thickness of the surface treatment layer.

B-2. First Surface Protection Film The first surface protection film 1 has a long shape and can be typically wound into a roll. A plurality of first through holes 1a and second through holes 1b are formed in advance in the first surface protection film 1 as described above. Moreover, the 3rd through-hole 1c is previously formed in the 1st surface protection film 1 as needed. The method of forming the through-hole is not particularly limited, and examples thereof include mechanical processing, laser processing, etching processing by chemical reaction, and the like. The first surface protective film 1 has a substrate 11 and an adhesive layer 12 .

Substrate 11 is formed of any suitable film. Specific examples of the material that is the main component of the film include ester resins such as polyethylene terephthalate resins, cycloolefin resins such as norbornene resins, olefin resins such as polypropylene, polyamide resins, and polycarbonate resins. , copolymer resins thereof, and the like, preferably ester-based resins. When the material of the base material 11 is an ester resin, the hardness of the first surface protection film 1 can be improved, and deformation of the through holes during transportation and/or lamination can be suppressed.

The thickness of the base material 11 is typically 20 μm to 250 μm, preferably 30 μm to 150 μm.

Adhesive layer 12 is formed from any appropriate adhesive (pressure sensitive adhesive). Examples of adhesives include (meth)acrylic adhesives, urethane adhesives, and silicone adhesives, and preferably (meth)acrylic adhesives. A "(meth)acrylic pressure-sensitive adhesive" refers to an acrylic pressure-sensitive adhesive and/or a methacrylic pressure-sensitive adhesive.

The thickness of the adhesive layer 12 is typically 1 μm to 20 μm, preferably 3 μm to 10 μm.

Such a first surface protective film 1 is attached to the polarizing plate 2 by bringing the adhesive layer 12 into contact with the polarizer 21 . With the first surface protection film 1 attached to the polarizing plate 2 , the substrate 11 is positioned on the side opposite to the polarizer 21 with respect to the adhesive layer 12 .

B-3. Second Surface Protection Film The second surface protection film 3 has a long shape and can be typically wound into a roll. The second surface protection film 3 can be described in the same manner as the first surface protection film 1 except that it does not have through holes (first through hole 1a, second through hole 1b and third through hole 1c). . The second surface protection film 3 has a substrate 31 that can be described in the same manner as the substrate 11 and an adhesive layer 32 that can be described in the same manner as the adhesive layer 12 . Such a second surface protective film 3 is attached to the polarizing plate 2 by bringing the adhesive layer 32 into contact with the protective layer 22 . With the second surface protective film 3 attached to the polarizing plate 2 , the substrate 31 is located on the side opposite to the protective layer 22 with respect to the adhesive layer 32 .

C. Polarizer Decolorization Treatment Step Next, the laminate 4 is subjected to a chemical decolorization treatment, and a treatment liquid (typically, a basic solution) is applied to the portions of the polarizer 21 exposed from the plurality of first through holes 1a. Contact is made via the first through hole 1a. The contact of the basic solution with the polarizer 21 is typically carried out by immersing the laminate 4 in the basic solution while transporting it, as shown in FIG. After the layered product 4 is immersed in the basic solution, the layered product 4 may be washed by being immersed in a washing liquid (for example, water, alcohol, and a mixed solvent thereof) while being transported.

When the polarizer 21 contains iodine as the dichroic substance, when a predetermined portion of the polarizer 21 is brought into contact with a basic solution, the iodine content of the contact portion is easily reduced, and the contact portion is selectively non-existent. A polarizing portion 21a can be formed. As a result, a predetermined portion of the polarizer 21 can be decolorized, and a plurality of non-polarized portions 21a can be formed in the polarizer 21 . When the iodine complex is destroyed to form the non-polarized portion, iodine may remain in the non-polarized portion. Then, as the polarizer is used, an iodine complex is formed again, and the non-polarizing portion may no longer have the desired properties. On the other hand, when the non-polarizing portion 21a is formed by contacting the basic solution and the polarizer 21, iodine itself is absorbed into the polarizer 21 (substantially, the non-polarizing portion 21a) as the basic solution is removed. ). As a result, the change in characteristics of the non-polarizing portion 21a due to the use of the polarizer 21 can be suppressed.

The content of the dichroic substance (typically iodine) in the non-polarizing portion 21a is preferably 1.0% by weight or less, more preferably 0.5% by weight or less, and even more preferably 0.2% by weight or less. is. If the content of the dichroic substance in the non-polarizing portion is within this range, the desired transparency can be sufficiently imparted to the non-polarizing portion 21a. For example, when a non-polarizing section is made to correspond to a camera section of an image display device, extremely excellent photographing performance can be achieved in terms of both brightness and color. On the other hand, the lower limit of the content of the dichroic substance in the non-polarizing portion 21a is usually below the detection limit. When iodine is used as the dichroic substance, the iodine content can be obtained from, for example, a calibration curve prepared in advance using standard samples from X-ray intensities measured by fluorescent X-ray analysis.

The difference between the content of the dichroic substance in the portion of the polarizer 21 other than the non-polarizing portion 21a and the content of the dichroic substance in the non-polarizing portion 21a is preferably 0.5% by weight or more, more preferably 1% by weight or more. If the content difference is within such a range, a non-polarizing portion having desired transparency can be formed.

The transmittance of the non-polarized portion 21a (for example, the transmittance measured with light having a wavelength of 550 nm at 23° C.) is preferably 50% or more, more preferably 60% or more, still more preferably 75% or more, and particularly preferably 90%. That's it. With such a transmittance, the non-polarized portion has desired transparency. As a result, when the polarizing plate is arranged so that the non-polarizing portion corresponds to the camera portion of the image display device, it is possible to prevent adverse effects on the photographing performance of the camera.

A basic solution includes a basic compound and a solvent that disperses and/or dissolves the basic compound. Any appropriate basic compound can be used as the basic compound. Basic compounds include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide, alkaline earth metal hydroxides such as calcium hydroxide, inorganic alkali metal salts such as sodium carbonate, and acetic acid. Examples include organic alkali metal salts such as sodium, aqueous ammonia, and the like. These basic compounds can be used alone or in combination. Among the basic compounds, alkali metal and/or alkaline earth metal hydroxides are preferred, and sodium hydroxide, potassium hydroxide and lithium hydroxide are more preferred. When the basic compound contains an alkali metal and/or alkaline earth metal hydroxide, the iodine complex can be efficiently ionized, and the non-polarizing portion can be formed more easily.

Any suitable solvent can be used as the solvent. Examples of solvents include water, alcohols such as ethanol and methanol, ethers, benzene, chloroform, and mixed solvents thereof. Among the solvents, water and alcohol are preferred. When the solvent contains water and/or alcohol, the iodide ions can be smoothly transferred from the polarizer 21 to the solvent, and can be easily removed as the basic solution is removed.

The concentration of the basic solution is, for example, 0.01N-5N, preferably 0.05N-3N, more preferably 0.1N-2.5N. If the concentration of the basic solution is in such a range, the iodine concentration in the portion of the polarizer 21 exposed from the first through hole 1a can be efficiently reduced, and the iodine complex in the polarizer 21 excluding this portion can be ionized. can be suppressed.

D. Post-treatment Step of Decolorization Treatment In one embodiment of the present invention, a post-treatment step is included after the decolorization treatment of the polarizer. When the portion of the polarizer 21 exposed from the plurality of first through holes 1a is brought into contact with a treatment liquid (typically, a basic solution) to form the non-polarization portion 21a, the non-polarization portion 21a is formed with an alkali metal and/or Metal salts of alkaline earth metals can be formed. These can generate hydroxide ions, and the generated hydroxide ions act (decompose/reduce) a dichroic substance (for example, an iodine complex) existing around the non-polarized portion 21a to (low concentration region) can be widened. Therefore, by performing a post-treatment step to reduce the metal salts of alkali metals and/or alkaline earth metals, the expansion of the non-polarized regions over time can be suppressed, and the desired shape of the non-polarized regions can be maintained. it is conceivable that.

Borate is a representative example of the metal salt capable of generating hydroxide ions. A borate is obtained by, for example, neutralizing the boric acid used in the stretching treatment described above with a basic solution (typically a solution of an alkali metal hydroxide and/or an alkaline earth metal hydroxide). can be generated by Borate (metaborate) can be hydrolyzed to generate hydroxide ions, for example, when the polarizer is placed in a humidified environment.

In the post-treatment step, a post-treatment liquid (typically, an acidic solution) is brought into contact with the non-polarized portions 21a exposed from the plurality of first through-holes 1a through the first through-holes 1a. The contact of the acid solution with the non-polarized portion 21a is typically carried out by immersing the laminate 4 in the acid solution while being transported, as shown in FIG. After the layered product 4 is immersed in the acid solution, the layered product 4 may be washed by being immersed in a washing liquid (for example, water, alcohol, or a mixed solvent thereof) while being transported.

When a post-treatment liquid (typically an acidic solution) is brought into contact with the non-polarizing portion 21a, the metal salt of the alkali metal and/or the alkaline earth metal is transferred to the post-treatment liquid (typically the acidic solution). It is possible to reduce the content of metal salts of alkali metals and/or alkaline earth metals in the non-polarizing portion 21a. In particular, when the post-treatment liquid is an acidic solution, the alkali metal and/or alkaline earth metal hydroxide remaining on the non-polarizing portion 21a is neutralized to chemically remove the alkali metal and/or alkaline earth metal. can be removed to

The content of the alkali metal and/or alkaline earth metal salt in the non-polarizing portion 21a after the post-treatment step is preferably 3.6% by weight or less, more preferably 2.5% by weight or less, and even more preferably 1% by weight. 0% by weight or less, and particularly preferably 0.5% by weight or less.

The acidic solution contains an acidic compound and a solvent that disperses and/or dissolves the acidic compound. Any appropriate acidic compound can be used as the acidic compound. Examples of acidic compounds include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, hydrogen fluoride and boric acid, and organic acids such as formic acid, oxalic acid, citric acid, acetic acid and benzoic acid. Acidic compounds can be used alone or in combination. Among the acidic compounds, inorganic acids are preferred, and hydrochloric acid, sulfuric acid and nitric acid are more preferred.

Any suitable solvent can be used as the solvent. The solvent is as described in the above section C, “Polarizer decolorization treatment step”.

The concentration of the acid solution is, for example, 0.01N-5N, preferably 0.05N-3N, more preferably 0.1N-2.5N.

E. Laminate Winding Step Next, the laminate 4 including the polarizer 21 formed with the plurality of non-polarizing portions 21a is continuously rolled into a roll by a rotating shaft (not shown) while applying any appropriate winding tension. take up effectively. A roll 5 of laminate 4 is thereby formed. In the roll 5, the first surface protective film 1 of the laminate 4 is positioned radially outward of the roll 5 with respect to the polarizing plate 2 to which the first surface protective film 1 is attached, and the second The surface protective film 3 is positioned radially inside the roll 5 with respect to the polarizing plate 2 to which the second surface protective film 3 is attached.

The winding tension is typically 50N-300N, preferably 70N-250N.
When the winding tension is equal to or less than the above upper limit, it is possible to stably suppress the occurrence of dents on the roll. When the winding tension is equal to or higher than the above lower limit, it is possible to suppress the occurrence of winding misalignment in the roll.

The length of the laminate 4 to be wound (rolling length) is typically 50 m to 6000 m, preferably 150 m to 4000 m. When the winding length is equal to or less than the above upper limit, it is possible to suppress excessive increase in the stress applied to the center of the roll. When the winding length is equal to or more than the above lower limit, productivity of the polarizing plate piece can be improved.

F. Step of Cutting out Polarizer Piece Next, after part of the laminate 4 is pulled out from the roll 5 , the first surface protection film 1 is removed (typically peeled off) from the pulled out laminate 4 . Thereafter, a detection unit (typically, a camera) (not shown) detects the position of the non-polarization portion 21a, and sets a cutout line C based on the detected position of the non-polarization portion 21a. Next, the polarizing plate 2 is cut out along the cutout line C using a punching blade (not shown). Thereby, the polarizing plate piece 20 is cut out from the polarizing plate 2 . The polarizer piece 20 includes a polarizer piece 210 including a non-polarizing portion 21 a and a protective layer piece 220 . In other words, the polarizer piece 210 including the non-polarized portion 21 a is cut out from the polarizer 21 .

The planar view shape of the polarizing plate piece 20 corresponds to the cutout line C described above, and may be any appropriate shape. Examples of the planar shape of the polarizing plate piece 20 include a circle, an ellipse, a square, a rectangle, a rhombus, and the like, preferably a rectangle. A polarizer piece 210 having a rectangular shape has a long side and a short side. The long side direction of the polarizer piece 210 may be substantially parallel to the absorption axis direction of the polarizer 21 or may cross the absorption axis direction of the polarizer 21 . As used herein, the expression “substantially parallel” includes cases in which the angle formed by two directions is 0°±7°, preferably 0°±5°, and more preferably 0°±3 °.

After that, the above operation is repeated, and the punching blade (not shown) is moved to cut out the next polarizing plate piece 20 from the polarizing plate 2 . In one embodiment of the present invention, a punching blade (not shown) is moved linearly from one width direction to the other to sequentially cut out polarizing plate pieces 20 from polarizing plate 2 . After the polarizing plate pieces 20 have been cut out from the polarizing plate 2 in one row in the width direction, the polarizing plate 2 is conveyed by a predetermined feeding pitch, and the next row is cut out. The operation of cutting out in a row in the width direction and the transportation of the polarizing plate 2 by one pitch after the operation are regarded as one cycle. can be cut out.

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these Examples. In addition, the measuring method of each characteristic is as follows.

(1) Roll hardness measurement On the surface of the rolls of the laminates obtained in Examples and Comparative Examples, a roll hardness measuring device (manufactured by Tapio, measuring method; deceleration measurement of a small hammer, measurement pitch; Seconds)) were brought into contact with each other, and 1080 points were measured at a pitch of 1 mm from one end to the other end in the axial direction of the roll. Table 1 shows the maximum roll hardness, the minimum roll hardness, and their difference (Gap).
Further, the laminate was pulled out from the roll, the first surface protection film was peeled off, and the number of dents having a diameter of 1 mm or more per 1 m ² of the polarizer was visually counted. Then, the number of dents was evaluated according to the following criteria. Table 1 shows the results.
○: 1 or less dents △: 2 to 4 dents ×: 5 or more dents

[Example 1]
1. Preparation of Polarizing Plate As a thermoplastic resin substrate, a long amorphous isophthalic copolymerized polyethylene terephthalate film (thickness: 100 μm, width: 3900 mm) having a Tg of about 75° C. was used. was subjected to corona treatment.
Polyvinyl alcohol (degree of polymerization: 4,200, degree of saponification: 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOSEFIMER") were mixed at a ratio of 9:1, and 100 parts by weight of PVA-based resin. was added with 13 parts by weight of potassium iodide and dissolved in water to prepare an aqueous PVA solution (coating solution).
The above PVA aqueous solution was applied to the corona-treated surface of the resin base material and dried at 60° C. to form a PVA-based resin layer having a thickness of 13 μm, thereby producing a laminate.
The resulting laminate was uniaxially stretched 2.4 times in the machine direction (longitudinal direction) in an oven at 130° C. (in-air auxiliary stretching treatment).
Next, the laminate was immersed in an insolubilizing bath (an aqueous boric acid solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40° C. for 30 seconds (insolubilizing treatment).
Then, the finally obtained polarizer is added to a dyeing bath (iodine aqueous solution obtained by blending iodine and potassium iodide at a weight ratio of 1:7 with respect to 100 parts by weight of water) at a liquid temperature of 30 ° C. It was immersed for 60 seconds while adjusting the concentration so that the single transmittance (Ts) was a desired value (dyeing treatment).
Next, it was immersed for 30 seconds in a cross-linking bath at a liquid temperature of 40°C (an aqueous solution of boric acid obtained by blending 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with respect to 100 parts by weight of water). (crosslinking treatment).
After that, while immersing the laminate in an aqueous solution of boric acid (boric acid concentration: 4% by weight, potassium iodide concentration: 5% by weight) at a liquid temperature of 70° C., the laminate was moved vertically (longitudinally) between rolls with different peripheral speeds. Uniaxial stretching was performed so that the stretching ratio was 5.5 times (underwater stretching treatment).
After that, the laminate was immersed in a washing bath (aqueous solution obtained by blending 4 parts by weight of potassium iodide with 100 parts by weight of water) at a liquid temperature of 20° C. (washing treatment).
Thereafter, while drying in an oven maintained at about 90° C., it was brought into contact with a heating roll made of SUS whose surface temperature was maintained at about 75° C. (dry shrinkage treatment).
Thus, a polarizer having a thickness of about 5 μm was formed on the resin substrate.
An acrylic resin film (thickness: 40 μm) having a glutarimide structure as a protective layer was attached to the surface of the obtained polarizer (the surface opposite to the resin substrate) via an ultraviolet curable adhesive. rice field. Specifically, the curable adhesive was applied so as to have a total thickness of about 2.0 μm, and was bonded using a roll machine. After that, UV rays were irradiated from the acrylic resin film side to cure the adhesive. Then, the resin substrate was peeled off to obtain a polarizing plate (width: 1300 mm) having a structure of acrylic resin film (protective layer)/polarizer.

2. First surface protective film On one surface of a long ester resin film (base material, thickness: 38 μm, width: 1300 mm), an acrylic pressure-sensitive adhesive is applied to a thickness of 5 μm, and the first A surface protective film was obtained. A Pinnacle (registered trademark) blade was used to form first through holes having a diameter of 3 mm in the first surface protective film at intervals of 220 mm in the width direction. Rows in which a plurality of first through holes are aligned in the width direction were formed at intervals of 310 mm in the longitudinal direction. Further, as shown in FIG. 5, a diameter A second through hole of 3 mm was formed. The second through-holes were arranged so as to overlap an imaginary line collectively passing through the plurality of first through-holes included in each row in the width direction.

3. Second surface protective film On one surface of a long ester resin film (base material, thickness 38 μm, width: 1300 mm), an acrylic adhesive is applied so that the thickness is 5 μm, and the second surface A protective film was obtained.

4. Production of Laminate and Roll After bonding the second surface protective film to the protective layer of the polarizing plate, the first surface protective film was bonded to the polarizer of the polarizing plate. As a result, a long laminate having a configuration of first surface protective film/polarizing plate/second surface protective film was obtained.
Next, the long laminate was wound up by a rotating shaft under conditions of a winding tension of 240 N and a winding length of 4000 m. Thus, a laminate roll was obtained.

[Example 2]
As shown in FIG. 6, a laminate roll was obtained in the same manner as in Example 1, except that the diameter of the second through holes was changed to 5 mm.

[Example 3]
As shown in FIG. 7, a laminate roll was obtained in the same manner as in Example 1, except that the diameter of the second through holes was changed to 1 mm.

[Example 4]
As shown in FIG. 9, in the same manner as in Example 1, except that a plurality of second through-holes having a diameter of 1 mm were formed so as to be aligned in the longitudinal direction corresponding to each row of the first through-holes. A roll of laminate was obtained.

[Example 5]
As shown in FIG. 10, in addition to the plurality of second through holes, a plurality of third through holes having a diameter of 1 mm are formed in the longitudinal direction corresponding to each row of the first through holes. A laminate roll was obtained in the same manner as in Example 4. The plurality of third through holes are positioned between the first through hole positioned at the other end in the width direction among the number of first through holes in each row and the other edge in the width direction of the first surface protection film. did.

[Example 6]
As shown in FIG. 8, the second through holes are formed by shifting in the longitudinal direction from a virtual line that collectively passes through the plurality of first through holes included in the row, and the third through holes with a diameter of 3 mm are formed. , except that it was formed between the first through hole located at the other end in the width direction of the plurality of first through holes in each row and the other edge in the width direction of the first surface protective film. A laminate roll was obtained in the same manner as in 1. Also, the third through-hole was formed to be shifted to the opposite side of the first through-hole with respect to the above imaginary line.

[Comparative Example 1]
As shown in FIG. 11, a laminate roll was obtained in the same manner as in Example 1, except that the first surface protection film did not have the second through holes.

[Comparative Example 2]
As shown in FIG. 12, a laminate roll was obtained in the same manner as in Comparative Example 1, except that the positions of the plurality of first through holes were changed.

[evaluation]
As is clear from Table 1, by forming the second through hole at a predetermined position, it is possible to suppress a local increase in the hardness (roll internal stress) of the roll of the laminate, and the polarizer has dents. It turns out that what happens can be suppressed.

The method for producing a polarizer piece of the present invention is suitably used for producing a polarizer used in an image display device (liquid crystal display device, organic EL device) with a camera such as a mobile phone such as a smart phone, a notebook PC, a tablet PC, and the like. be done.

REFERENCE SIGNS LIST 1 first surface protective film 1a first through hole 1b second through hole 1c third through hole 2 polarizing plate 21 polarizer 21a non-polarizing portion 22 protective layer 3 second surface protective film

Claims (5)

A long surface protective film having a plurality of first through-holes spaced apart in a width direction orthogonal to the longitudinal direction of the surface protective film, a dichroic substance being added to the surface protective film a step of forming a laminate by bonding it to a long polarizer having;
a step of decolorizing the portion of the polarizer exposed from the plurality of first through holes through the first through holes to form a plurality of non-polarizing portions in the polarizer;
winding a laminate including a polarizer in which the plurality of non-polarizing portions are formed into a roll;
After the winding, a step of cutting out a plurality of polarizer pieces including the non-polarized portion from the polarizer,
The surface protection film is
The polarizer further has a second through-hole positioned between a first through-hole positioned at one end in the width direction of the plurality of first through-holes and one edge in the width direction of the surface protection film. How to make pieces. opening areas of the plurality of first through holes are substantially the same, and
2. The method of manufacturing a polarizer piece according to claim 1, wherein the opening area of the second through holes is 0.5 or more with respect to the opening area of each of the first through holes. opening areas of the plurality of first through holes are substantially the same, and
The opening area of the second through holes is less than 0.5 with respect to the opening area of each of the first through holes,
2. The method of manufacturing a polarizer piece according to claim 1, wherein a plurality of said second through-holes are arranged at intervals in said longitudinal direction. The surface protection film is
Further having a third through hole positioned between a first through hole positioned at the other end in the width direction among the plurality of first through holes and the other edge in the width direction of the surface protection film, A method for manufacturing a polarizer piece according to any one of claims 1 to 3. The distance in the width direction between the first through hole located at one end in the width direction and the second through hole, and the width direction between the second through hole and one edge of the surface protection film. is less than or equal to the widthwise interval between adjacent first through holes among the plurality of first through holes. Method.

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