JP2016061805A - Production method of polarizer having non-polarizing part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method by which a high-quality polarizer having a non-polarizing part can be efficiently produced.SOLUTION: The production method of a polarizer having a non-polarizing part includes: a step of subjecting a long polarizing film laminate, which includes a polarizer and a surface protective film disposed on one surface side of the polarizer and has an exposed part where the polarizer is exposed on the one surface side, to a wet process; and a process liquid removal step of removing a process liquid used in the wet process. The process liquid removal step is carried out while the polarizing film laminate is conveyed with the exposed part facing downward.SELECTED DRAWING: None

Description

  The present invention relates to a method for manufacturing a polarizer having a non-polarizing portion.

  Some image display devices such as mobile phones and notebook personal computers (PCs) are equipped with internal electronic components such as cameras. Various studies have been made for the purpose of improving the camera performance and the like of such an image display device (for example, Patent Documents 1 to 6). However, with the rapid spread of smartphones and touch panel type information processing devices, further improvements in camera performance and the like are desired. Further, in order to cope with diversification and high functionality of the shape of the image display device, there is a demand for a polarizing plate partially having polarization performance. In order to realize these demands industrially and commercially, it is desired to manufacture an image display device and / or its components at an acceptable cost. Matters are left behind.

JP 2011-81315 A JP 2007-241314 A US Patent Application Publication No. 2004/0212555 Korean Published Patent No. 10-2012-0118205 Korean Patent No. 10-1293210 JP 2012-137738 A

  The present invention has been made to solve the above-described conventional problems, and a main object thereof is to provide a manufacturing method capable of efficiently manufacturing a polarizer having a high-quality non-polarizing portion.

The manufacturing method of the polarizer which has a non-polarization part of the present invention is provided with a polarizer and a surface protection film arranged on one side of the polarizer, and has an exposed part where the polarizer is exposed on the one side. Including a step of wet-treating the long polarizing film laminate and a treatment liquid removal step of removing the treatment liquid used in the wet treatment, wherein the treatment liquid removal step faces the polarizing film laminate downward It is carried out while being conveyed.
In one embodiment, the angle which conveys the polarizing film laminated body in the said process liquid removal process is 0 degree-90 degrees.
In one embodiment, the treatment liquid removal step includes horizontally transporting the polarizing film laminate.
In one embodiment, the treatment liquid removing step is performed such that the polarizing film laminate is inclined and conveyed, and an exposed portion of the polarizing film laminate that is inclined and conveyed is opposed to the treatment liquid removing unit.
In one embodiment, the treatment liquid removing step is performed in combination with a blower, an air blow, an air knife, and wiping.

  Polarizing film laminate having a polarizer and a surface protective film disposed on one side of the polarizer, and having an exposed portion where the polarizer is exposed on the one side for the purpose of performing wet treatment only on a desired portion A wet process may be performed using a body. The surface protective film is required to have a certain thickness in order to sufficiently protect the polarizer. In such a case, for example, the processing liquid used for the wet processing may remain in the exposed portion. Depending on the type of the treatment liquid, there is a possibility of adversely affecting the characteristics of the polarizer. Further, when the remaining treatment liquid evaporates, water marks and the like remain on the surface of the polarizer, which may adversely affect the appearance. Therefore, development of a method for producing a polarizer that is excellent in the properties and appearance of the polarizer and that has high production efficiency is desired.

  According to the manufacturing method of the present invention, there is provided a manufacturing method capable of efficiently manufacturing a polarizer having a high-quality non-polarizing portion even when a polarizing film laminate having a surface protective film is used. In the manufacturing method of this invention, the removal process of the process liquid used by the wet process is performed, conveying so that the exposed part of a polarizing film laminated body may face downward. As a result, the treatment liquid remaining in the exposed portion of the polarizing film laminate may fall according to gravity, preventing the treatment liquid from remaining in the exposed portion and preventing the treatment liquid from reattaching to the exposed portion in the treatment liquid removing step. . Although the treatment liquid remains, problems may occur in the characteristics and appearance of the obtained polarizer. In the present invention, these problems can be prevented, and a polarizer having a high-quality non-polarizing part is efficiently produced. can do.

It is a schematic sectional drawing of the polarizing film laminated body used by one Embodiment of this invention. It is a schematic sectional drawing of the surface protection film used by one embodiment of this invention. It is a schematic perspective view of the surface protection film by one Embodiment of this invention. It is a schematic perspective view explaining bonding of the surface protection film and a polarizing plate in the manufacturing method of the polarizer using the surface protection film by one Embodiment of this invention. It is the schematic which shows the process liquid removal process of the polarizing film laminated body performed by one Embodiment of this invention. It is the schematic which shows the process liquid removal process of the polarizing film laminated body performed by another embodiment of this invention.

  Hereinafter, although preferable embodiment of this invention is described, this invention is not limited to these embodiment.

  The manufacturing method of the polarizer which has a non-polarization part of the present invention is provided with a polarizer and a surface protection film arranged on one side of the polarizer, and has an exposed part where the polarizer is exposed on the one side. It includes a step of wet-treating the long polarizing film laminate and a treatment liquid removal step of removing the treatment liquid used in the wet treatment. In the manufacturing method of this invention, a process liquid removal process is performed, conveying a polarizing film laminated body so that an exposed part may face downward. By performing the treatment liquid removing step while conveying the exposed portion downward, the treatment liquid remaining in the exposed portion can fall due to gravity. Therefore, in the treatment liquid removal step, the treatment liquid remaining on the exposed portion of the polarizing film laminate can be removed and the removed treatment liquid can be prevented from reattaching to the exposed portion. Conventionally, when a surface protection film having a certain thickness is used, not only the treatment liquid cannot be completely removed in the treatment liquid removal step, but the treatment liquid is reattached, and the properties and appearance of the obtained polarizer are impaired. There was a problem. However, in the production method of the present invention, the treatment liquid that could remain conventionally is removed and the re-adhesion of the treatment liquid is prevented, so that adverse effects on the properties and appearance of the polarizer can be prevented. In addition, although the polarizer before forming a non-polarization part is an intermediate body of the polarizer which has a non-polarization part obtained by the manufacturing method of this invention strictly, it is only called a polarizer in this specification. A person skilled in the art can easily understand from the description of the present specification whether "polarizer" means an intermediate or a polarizer having a non-polarization part obtained by the production method of the present invention. be able to.

A. Process for Producing Polarized Film Laminate In the method for producing a polarizer of the present invention, an exposed portion comprising a polarizer and a surface protective film disposed on one side of the polarizer, and the polarizer exposed on the one side. Wet treatment is performed using a polarizing film laminate having the following. Since this polarizing film laminate has an exposed portion where the polarizer is exposed, in the wet processing, only the exposed portion of the polarizer is subjected to the wet processing.

  FIG. 1 is a schematic cross-sectional view of a polarizing film laminate used in one embodiment of the present invention. The polarizing film laminate 100 is long and has a surface protective film (hereinafter also referred to as a first surface protective film) 50 having a through hole 61, a polarizer 10, a protective film 20, and a second surface. The protective film 30 is provided in this order. In this embodiment, a polarizing plate including a polarizer 10 and a protective film 20 that protects the polarizer 10 is used. However, a polarizer having a form other than the form of a polarizing plate (for example, a single resin film) A certain polarizer, a resin substrate / polarizer laminate) may be used. The surface protection film 50 has through holes 61 arranged at predetermined intervals (that is, in a predetermined pattern) in the longitudinal direction and / or the width direction. The surface protective film 50 used in the present invention has through holes 61 that are continuously arranged at least in the longitudinal direction. The polarizing film laminate 100 has an exposed portion 51 where the polarizer 10 is exposed from the through hole 61. The exposed portions 51 are arranged at predetermined intervals in at least the long direction of the long polarizer 10. The surface protection films 50 and 30 are laminated via an adhesive layer made of any appropriate adhesive (not shown). In this specification, “long shape” means an elongated shape having a sufficiently long length with respect to the width. For example, an elongated shape having a length that is 10 times or more, preferably 20 times or more the width. Including.

  FIG. 2 is a schematic cross-sectional view of a surface protective film used in one embodiment of the present invention. The surface protection film 50 is long and has a resin film 70 and an adhesive layer 80 provided on one surface of the resin film 70. The surface protective film 50 has through-holes 61 penetrating the resin film 70 and the pressure-sensitive adhesive layer 80 arranged at predetermined intervals (that is, in a predetermined pattern) in the longitudinal direction and / or the width direction. The arrangement pattern of the through holes 61 can be appropriately set according to the purpose. FIG. 3 is a schematic perspective view of a surface protective film according to one embodiment of the present invention. For example, as shown in FIG. 3, the through holes 61 can be arranged at substantially equal intervals in both the longitudinal direction and the width direction. Note that “substantially equidistant in both the longitudinal direction and the width direction” means that the spacing in the longitudinal direction is equal and the spacing in the width direction is equal. The interval in the scale direction and the interval in the width direction need not be equal. For example, when the interval in the longitudinal direction is L1 and the interval in the width direction is L2, L1 = L2 may be satisfied, or L1 ≠ L2.

  FIG. 4 is a schematic perspective view illustrating the bonding of the surface protective film and the polarizing plate in the method for producing a polarizer using the surface protective film according to one embodiment of the present invention. The polarizing film laminate 100 can be produced by laminating a long surface protective film 50 on the surface of the long polarizer 10. In one embodiment, a polarizing film laminate is produced using a surface protective film having a long polarizer and a long pressure-sensitive adhesive layer. By using a surface protective film having an adhesive layer, a polarizing film laminate can be produced by roll-to-roll as shown in FIG. Furthermore, when the polarizing film laminated body 100 is provided with the 2nd protective film 30, the elongate 2nd surface protective film 30 can be laminated | stacked by roll to roll. The second surface protective film may be bonded together with the surface protective film having the through hole, or may be bonded before the surface protective film having the through hole is bonded, and the surface protective film having the through hole is bonded. You may bond together after bonding. It goes without saying that the same procedure can be applied to a polarizer having a form other than that of the polarizing plate (for example, a polarizer that is a single resin film, a laminate of a resin base material / polarizer).

A-1. Production of Polarizer Any appropriate polarizer may be employed as the polarizer 10 used in the polarizing film laminate 100. The polarizer is typically composed of a resin film. The resin film is typically a polyvinyl alcohol resin (hereinafter referred to as “PVA resin”) film containing a dichroic substance such as iodine or an organic dye. The resin film (typically, PVA resin film) constituting the polarizer may be a single film, or a resin layer (typically, PVA resin layer) formed on the resin substrate. ).

  As the polarizer, a polarizer containing iodine is preferable. When the polarizer contains iodine as a dichroic substance, it is possible to reduce the iodine concentration in the exposed portion by immersion in a basic solution described later, and as a result, selectively form a non-polarizing portion only in the exposed portion. it can. Therefore, a non-polarizing part can be selectively formed in a predetermined part of the polarizer with very high production efficiency without complicated operation.

  The polarizer can be made by any suitable method. When the polarizer is a single PVA-based resin film, the polarizer can be produced by a method well known and commonly used in the art. When the polarizer is a PVA-based resin layer formed on a resin base material, the polarizer can be produced, for example, by a method described in JP 2012-73580 A. This publication is incorporated herein by reference in its entirety.

  The thickness of the polarizer can be set to any appropriate value. The thickness is preferably 30 μm or less, more preferably 25 μm or less, still more preferably 20 μm or less, and particularly preferably less than 10 μm. On the other hand, the thickness is preferably 0.5 μm or more, more preferably 1 μm or more. With such a thickness, a polarizer having excellent durability and optical characteristics can be obtained. Moreover, when an alkali process is included as a wet process, a non-polarizing part can be formed favorably, so that thickness is thin. For example, when forming a non-polarization part by decoloring by alkali treatment, the contact time of a process liquid and a resin film (polarizer) can be shortened.

  When producing a polarizing film laminated body using a polarizing plate, in one embodiment, a protective film is bonded together to the single side | surface or both surfaces of the polarizer which is a single resin film. In another embodiment, a protective film is bonded to the polarizer surface of the resin base material / polarizer laminate, the resin base material is then peeled off, and further separated from the release surface of the resin base material as necessary. The protective film can be bonded. In this specification, the term “protective film” means a polarizer protective film as described above, and is different from a surface protective film (a film that temporarily protects a polarizing plate during operation). Bonding of the protective film can be typically performed by roll-to-roll.

  Examples of the material for forming the protective film include cellulose resins such as diacetyl cellulose and triacetyl cellulose, (meth) acrylic resins, cycloolefin resins, olefin resins such as polypropylene, and ester resins such as polyethylene terephthalate resins. , Polyamide resins, polycarbonate resins, and copolymer resins thereof.

  The thickness of the protective film is preferably 10 μm to 100 μm. The protective film is typically laminated on the polarizer via an adhesive layer (specifically, an adhesive layer or an adhesive layer). The adhesive layer is typically formed of a PVA adhesive or an activated energy ray curable adhesive. The pressure-sensitive adhesive layer is typically formed of an acrylic pressure-sensitive adhesive.

  Moreover, the polarizing plate may further have any appropriate optical functional layer depending on the purpose. Representative examples of the optical functional layer include a retardation film (optical compensation film) and a surface treatment layer.

A-2. Production of Surface Protective Film The surface protective film 50 is provided with a through hole 61 corresponding to a position where a non-polarizing portion of a polarizer (polarizer intermediate) is formed. In one embodiment, the surface protective film is a laminate having any appropriate resin film and an adhesive layer provided on one surface of the resin film, and the resin film and the adhesive layer (Surface protective film in FIG. 2).

  For example, as described above, the through holes 61 of the surface protective film 50 can be arranged at substantially equal intervals in both the longitudinal direction and the width direction (FIG. 3). Alternatively, the through holes 61 may be arranged at substantially equal intervals in the length direction and at different intervals in the width direction; they are arranged at different intervals in the length direction and substantially in the width direction. In general, they may be arranged at equal intervals (both not shown). When the through holes are arranged at different intervals in the longitudinal direction or the width direction, the intervals between the adjacent through holes may be all different, or only a part (the interval between specific adjacent through holes) may be different. Good. Further, a plurality of regions may be defined in the longitudinal direction of the surface protection film 50, and the interval between the through holes 61 in the longitudinal direction and / or the width direction may be set for each region. When only one size polarizer is cut from one long polarizer, the through holes 61 can be arranged at substantially equal intervals in both the long direction and the width direction. With such a configuration, it is easy to control the cutting of the polarizer to a predetermined size in accordance with the size of the image display device, and the yield can be improved. Furthermore, since the position of the non-polarizing part of the obtained polarizer can be set accurately, the position of the non-polarizing part in the obtained polarizer of a predetermined size can be controlled well. As a result, since the variation in the position of the non-polarizing portion for each obtained polarizer of a predetermined size is reduced, it is possible to obtain a polarizer of a predetermined size with no quality variation.

In one embodiment, the through hole 61 has a straight line connecting adjacent through holes in the longitudinal direction substantially parallel to the longitudinal direction, and a straight line connecting adjacent through holes in the width direction. Are arranged so as to be substantially parallel to the width direction. In another embodiment, the through-hole 61 has a straight line connecting adjacent through holes in the longitudinal direction substantially parallel to the longitudinal direction, and a straight line connecting adjacent through-holes in the width direction. Are arranged to have a predetermined angle θ _W with respect to the width direction. In yet another embodiment, the through hole 61 has a straight line connecting through holes adjacent in the longitudinal direction having a predetermined angle θ _L with respect to the longitudinal direction, and the through holes adjacent in the width direction. Are arranged so as to have a predetermined angle θ _W with respect to the width direction. θ _L and / or θ _W is preferably more than 0 ° and not more than ± 10 °. Here, “±” means to include both clockwise and counterclockwise directions with respect to the reference direction (long direction or width direction). By immersing the polarizing film laminate including the surface protective film having the through holes in this manner in a basic solution, the non-polarizing portion is formed in a desired pattern while the long polarizing film laminate is being conveyed by a roll. Can be formed. As a result, it is possible to form the non-polarizing portion by precisely controlling the arrangement pattern over the entire long polarizer. Further, when a plurality of sizes of polarizers are cut from one long polarizer by forming the non-polarizing parts with a desired arrangement pattern, the non-polarizing parts in the longitudinal direction and / or the width direction are cut. The interval can be changed according to the size of the polarizer to be cut. Here, depending on the image display apparatus, in order to improve the display characteristics, it may be required to dispose the polarizer at a maximum offset of about 10 ° with respect to the long side or the short side of the apparatus. Since the absorption axis of the polarizer is expressed in the longitudinal direction or the width direction, the positional relationship between the non-polarizing part and the absorption axis in such a case can be obtained by forming the non-polarizing part using the above surface protective film. Can be controlled uniformly over the entire long polarizer, and a final product with excellent axial accuracy (and therefore excellent optical properties) can be obtained. Therefore, the direction of the absorption axis of the cut polarizer (for example, cutting in the longitudinal direction and / or the width direction, punching) can be precisely controlled to a desired angle, and for each polarizer Variation in the direction of the absorption axis can be remarkably suppressed. It goes without saying that the arrangement pattern of the through holes is not limited to the illustrated example. For example, in the through hole 61, a straight line connecting adjacent through holes in the longitudinal direction has a predetermined angle θ _L with respect to the long direction, and a straight line connecting adjacent through holes in the width direction is It may be arranged to be substantially parallel to the direction. Further, a plurality of regions may be defined in the longitudinal direction of the surface protective film 50, and θ _L and / or θ _W may be set for each region.

  Arbitrary appropriate shapes may be employ | adopted for the planar view shape of the through-hole of a 1st surface protection film according to the objective. Specific examples include a circle, an ellipse, a square, a rectangle, and a rhombus.

  The through hole of the first surface protective film is formed by, for example, mechanical punching (for example, punching, engraving blade punching, plotter, water jet) or removal of a predetermined portion of the first surface protective film (for example, laser ablation or chemical Dissolution).

  The first surface protective film is preferably a film having a high hardness (for example, elastic modulus). This is because the deformation of the through-hole during conveyance and / or bonding can be prevented. Surface protective film forming materials include ester resins such as polyethylene terephthalate resins, cycloolefin resins such as norbornene resins, olefin resins such as polypropylene, polyamide resins, polycarbonate resins, and copolymer resins thereof. Etc. Preference is given to ester resins (especially polyethylene terephthalate resins). Such a material has an advantage that the elastic modulus is sufficiently high and deformation of the through-hole hardly occurs even when tension is applied during conveyance and / or bonding.

  The thickness of the first surface protective film is preferably 20 μm to 250 μm, more preferably 30 μm to 150 μm. If the thickness of the surface protective film is in the above range, the depth of the exposed portion becomes deep and the treatment liquid is prevented from remaining excessively while maintaining the protective effect of the polarizer in the manufacturing process of the polarizer. obtain.

The elastic modulus of the first surface protective film is preferably 2.2 kN / mm ^{2 to} 4.8 kN / mm ² . If the elastic modulus is within the above range, the depth of the exposed portion becomes deep and the treatment liquid can be prevented from remaining excessively while maintaining the protective effect of the polarizer in the manufacturing process of the polarizer. The elastic modulus is measured according to JIS K 6781.

  The tensile elongation of the first surface protective film is preferably 90% to 170%. If the tensile elongation of the surface protective film is within the above range, the depth of the exposed portion may be increased and the treatment liquid may remain excessively while maintaining the protective effect of the polarizer in the manufacturing process of the polarizer. Can be suppressed. The tensile elongation is measured according to JIS K 6781.

  Moreover, as above-mentioned, the polarizing film laminated body 100 may be equipped with the 2nd surface protection film 30 in the side by which the said surface protection film is not arrange | positioned. As the second surface protective film, a film similar to the surface protective film can be used except that no through-hole is provided. Furthermore, as the second surface protective film, a soft (eg, low elastic modulus) film such as a polyolefin (eg, polyethylene) film can be used. By using the second surface protective film, the polarizer can be further appropriately protected. Specifically, when immersed in a basic solution, the polarizing plate (polarizer / protective film) can be further appropriately protected, and as a result, the non-polarizing part can be formed more satisfactorily. .

  Any appropriate pressure-sensitive adhesive layer can be adopted as the pressure-sensitive adhesive layer as long as the effects of the present invention are obtained. Examples of the base resin for the pressure-sensitive adhesive include acrylic resins, styrene resins, and silicone resins. Acrylic resins are preferred from the viewpoints of chemical resistance, adhesion for preventing the treatment liquid from entering during immersion, flexibility in the adherend, and the like. Moreover, the pressure-sensitive adhesive may contain a crosslinking agent, and examples of the crosslinking agent that can be included in the pressure-sensitive adhesive include isocyanate compounds, epoxy compounds, and aziridine compounds. The pressure-sensitive adhesive may contain, for example, a silane coupling agent. The formulation of the pressure-sensitive adhesive can be appropriately set according to the purpose.

  The pressure-sensitive adhesive layer can be formed by any appropriate method. Specific examples include a method of applying a pressure-sensitive adhesive solution on a resin film and drying, a method of forming a pressure-sensitive adhesive layer on a separator, and transferring the pressure-sensitive adhesive layer to the resin film. Examples of the coating method include roll coating methods such as reverse coating and gravure coating, spin coating methods, screen coating methods, fountain coating methods, dipping methods, and spray methods.

  The thickness of the pressure-sensitive adhesive layer is preferably 5 μm to 60 μm, more preferably 5 μm to 30 μm. If the thickness is too thin, the adhesiveness becomes insufficient, and bubbles or the like may enter the adhesive interface. If the thickness is too thick, problems such as sticking out of the adhesive easily occur. The thickness of the pressure-sensitive adhesive layer can be adjusted together with the thickness of the resin film so that the thickness of the surface protective film falls within the above range.

B. Wet treatment process In the manufacturing method of this invention, a wet process is performed using the polarizing film laminated body obtained by said process. Thereby, a wet process can be performed only to the desired part of a polarizer. Specifically, when an alkali treatment with a basic solution is performed as a wet treatment, the alkali treatment can be performed only on a portion exposed from the surface protective film of the polarizer, and a non-polarizing portion can be formed only on this portion. it can. Further, in the manufacturing method of the present invention, the processing liquid removal process described later is performed while the exposed portion is conveyed downward, so that not only the processing liquid is removed but also the removed processing liquid is reapplied to the exposed portion. It can also prevent adhesion. Therefore, adverse effects on the properties and appearance of the obtained polarizer can be prevented.

  The contact method between the treatment liquid and the polarizing film laminate in the wet treatment is not particularly limited, and examples include immersion in the treatment liquid, dropping of the treatment liquid, application, or spraying. Immersion is preferred because of its excellent production efficiency. In addition, the contact time between the polarizing film laminate and the treatment liquid can be set to any appropriate time depending on conditions such as the purpose of the wet treatment, the concentration of the treatment liquid, the thickness of the polarizing film laminate, and the like.

  There is no restriction | limiting in particular as a wet process in which the said polarizing film laminated body can be provided, The wet process which can be used at the manufacturing process of a polarizer is mentioned. Typically, in a method for producing a polarizer having a non-polarizing part, a wet treatment using a basic solution, a wet treatment using an acidic solution, and cleaning after the wet treatment using a basic solution and / or an acidic solution. Process.

  When performing the wet process by immersion, when a polarizing film laminated body is carried out from a processing bath, it may be conveyed so that an exposed part may face downward. When immersing in the treatment liquid, the orientation of the polarizing film laminate when carrying it into the treatment liquid is not particularly limited, and the polarizing film laminate may be transported so that the exposed portion faces upward, so that it faces downward. It may be conveyed. When performing the wet process by immersion, the angle which conveys a polarizing film laminated body in a liquid is 0 degree-90 degrees, for example. In one embodiment, the wet treatment can be performed by conveying the polarizing film laminate so that the exposed portion faces downward. In this case, it is preferable that the polarizing film laminate is brought into contact with the treatment liquid while being inclined and conveyed. This is because the treatment liquid sufficiently enters the downward exposed portion of the polarizing film laminate by performing the inclined conveyance, and the effect obtained by performing the wet treatment is sufficiently obtained. It is preferable to carry the inclined conveyance at the time of carrying in to a process liquid inclinedly so that an exposed part may face down a polarizing film laminated body. In addition, in this specification, inclined conveyance means conveying a polarizing film laminated body at an angle exceeding 0 degree.

  The inclination angle when the polarizing film laminate is conveyed in an inclined manner can be adjusted by any appropriate means. For example, it can be adjusted by adjusting the position of a roll for conveying the film.

  Moreover, when performing an immersion process, when carrying out a polarizing film laminated body from a process liquid, it is preferable to carry out a polarizing film laminated body so that an exposed part may face downward. By carrying out the polarizing film laminate so that the exposed portion faces downward, the polarizing film laminate can be carried out and the processing liquid in the exposed portion can be removed.

B-1. Wet treatment (basic treatment) using basic solution
The wet treatment using the basic solution (hereinafter, also referred to as alkali treatment) can be performed by bringing the polarizing film laminate and the basic solution into contact with each other. The exposed portion can be decolored by a wet treatment using a basic solution, and a non-polarized portion can be formed by the decolorization. As the polarizer used in the polarizing film laminate, a polarizer containing iodine is preferable. When the polarizer contains iodine as a dichroic substance, the exposed portion of the polarizer is brought into contact with the basic solution to reduce the iodine concentration in the exposed portion. As a result, only the exposed portion is selectively unpolarized. The part can be formed. Therefore, it is possible to selectively form the non-polarizing portion in a predetermined portion of the polarizer with very high manufacturing efficiency without complicated operation. When iodine remains in the polarizer, even if the iodine complex is destroyed to form a non-polarizing part, the iodine complex is formed again with the use of the polarizer, and the non-polarizing part has the desired characteristics. There is a risk that it will disappear. In the present embodiment, iodine itself is removed from the polarizer (substantially the non-polarizing part) by removing the basic solution described later. As a result, it is possible to prevent a change in the characteristics of the non-polarizing part accompanying the use of the polarizer.

  The wet treatment using the basic solution can be performed by any appropriate means as described above. When a long polarizing film laminate is used as the polarizing film laminate, since the decoloring treatment can be performed while the polarizing film laminate is being transported, soaking is preferable from the viewpoint that the production efficiency is remarkably increased. . As described above, by using the first surface protective film (and the second surface protective film as necessary), the iodine concentration is not reduced in the portion other than the exposed portion of the polarizing film laminate, so that the non-immersion by immersion. A polarizing part can be formed. Specifically, by immersing the polarizing film laminate in the basic solution, only the exposed portion of the polarizing film laminate contacts the basic solution.

  The formation of the non-polarizing part by the basic solution will be described in more detail. After contact with the exposed portion of the polarizer in the polarizing film laminate, the basic solution penetrates into the exposed portion. The iodine complex contained in the exposed part is reduced by the base contained in the basic solution to become iodine ions. When the iodine complex is reduced to iodine ions, the polarization performance of the exposed portion is substantially lost, and a non-polarized portion is formed in the exposed portion. Moreover, the transmittance | permeability of an exposed part improves by reduction | restoration of an iodine complex. Iodine that has become iodine ions moves from the exposed portion into the solvent of the basic solution. As a result, by removing the basic solution described later, iodine ions are also removed from the exposed portion together with the basic solution. In this way, a non-polarizing portion is selectively formed in a predetermined portion of the polarizer, and the non-polarizing portion is stable without change over time. A portion where the basic solution is not desired by adjusting the material, thickness and mechanical properties of the first surface protective film, the concentration of the basic solution, and the immersion time of the polarizing film laminate in the basic solution, etc. (As a result, a non-polarizing part is formed in an undesired part) can be prevented.

  Any appropriate basic compound can be used as the basic compound contained in the basic solution. Examples of basic compounds include hydroxides of alkali metals such as sodium hydroxide, potassium hydroxide and lithium hydroxide, hydroxides of alkaline earth metals such as calcium hydroxide, inorganic alkali metal salts such as sodium carbonate, acetic acid Organic alkali metal salts such as sodium, aqueous ammonia and the like can be mentioned. The basic compound contained in the basic solution is preferably an alkali metal hydroxide, more preferably sodium hydroxide, potassium hydroxide, or lithium hydroxide. By using a basic solution containing an alkali metal hydroxide, the iodine complex can be ionized efficiently, and a non-polarizing part can be formed more easily. These basic compounds may be used alone or in combination of two or more.

  Any appropriate solvent can be used as the solvent of the basic solution. Specific examples include water, alcohols such as ethanol and methanol, ethers, benzene, chloroform, and mixed solvents thereof. Since iodine ions migrate to the solvent satisfactorily and iodine ions can be easily removed in the subsequent removal of the basic solution, the solvent is preferably water or alcohol.

  The concentration of the basic solution is, for example, 0.01N to 5N, preferably 0.05N to 3N, and more preferably 0.1N to 2.5N. When the concentration of the basic solution is in such a range, the iodine concentration inside the polarizer can be efficiently reduced, and ionization of the iodine complex in a portion other than the exposed portion can be prevented.

  The liquid temperature of the basic solution is, for example, 20 ° C to 50 ° C. The contact time between the polarizing film laminate (substantially, the exposed portion of the polarizer) and the basic solution depends on the thickness of the polarizer, the type of basic compound contained in the basic solution used, and the basic compound. For example, 5 seconds to 30 minutes.

  The basic solution can be removed by any appropriate means as necessary after contact with the exposed portion of the polarizer (after formation of the non-polarizing portion). Specific examples of the method for removing the basic solution include suction removal, natural drying, heat drying, air drying, reduced pressure drying, a treatment liquid removing step and washing described later. The drying temperature in the case of removing the basic solution by drying is, for example, 20 ° C to 100 ° C.

B-2. Wet treatment (acid treatment) using acidic solution
A wet treatment using an acidic solution (hereinafter also referred to as an acid treatment) can be performed by bringing the polarizing film laminate and the acidic solution into contact with each other. The wet treatment using the acidic solution is preferably performed in combination with the alkali treatment, and the wet treatment with the acidic solution is preferably performed after the alkali treatment. After the alkali treatment, the basic solution remaining in the non-polarizing part can be removed to a better level by contacting with an acidic solution. Moreover, the dimensional stability and durability of a non-polarizing part can improve by making it contact with an acidic solution.

  The contact between the polarizing film laminate and the acidic solution can be performed by any appropriate means. Specifically, immersion of the polarizing film laminate in an acidic solution, or dropping, application or spraying of an acidic solution onto the polarizing film laminate can be mentioned. The contact with the acidic solution is preferably immersion, as in the case of the contact with the basic solution. The contact with the acidic solution may be performed after removing the basic solution or may be performed without removing the basic solution.

  Any appropriate acidic compound can be used as the acidic compound contained in the acidic solution. Examples of the acidic compound include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and hydrogen fluoride, and organic acids such as formic acid, oxalic acid, citric acid, acetic acid, and benzoic acid. The acidic compound contained in the acidic solution is preferably an inorganic acid, more preferably hydrochloric acid, sulfuric acid, or nitric acid. These acidic compounds may be used alone or in combination.

  As the solvent for the acidic solution, those exemplified as the solvent for the basic solution can be used. The density | concentration of the said acidic solution is 0.01N-5N, for example, Preferably it is 0.05N-3N, More preferably, it is 0.1N-2.5N.

  The liquid temperature of the acidic solution is, for example, 20 ° C to 50 ° C. The contact time between the polarizing film laminate (substantially, the exposed portion of the polarizer) and the acidic solution depends on the thickness of the resin film (polarizer), the type of acidic compound contained in the acidic solution used, and the acidic compound. For example, 5 seconds to 30 minutes. As needed, after making a polarizing film laminated body and an acidic solution contact, you may remove immediately.

  The acidic solution can be removed by any appropriate means as necessary after contact with the exposed portion of the polarizer. Specific examples of the method for removing the acidic solution include suction removal, natural drying, heat drying, blown drying, reduced pressure drying, a treatment liquid removal step and washing described later. When removing an acidic solution by drying, it can be performed, for example, by transporting the polarizing film laminate in an oven. The drying temperature is, for example, 20 ° C. to 100 ° C., and the drying time is, for example, 5 seconds to 600 seconds.

B-3. Washing Washing can be performed to remove the treatment liquid and foreign matter adhering to the polarizing film laminate surface in each step. For example, in the manufacturing method of this invention, it can carry out after the said alkali treatment and / or acid treatment.

  Examples of the liquid used for washing include water (pure water), alcohols such as methanol and ethanol, acidic aqueous solutions, and mixed solvents thereof. Preferably, it is water. The cleaning may be performed once, or a plurality of cleanings may be performed as one step.

  The treatment liquid after washing can be removed by any appropriate means as necessary. Specific examples of the method for removing the treatment liquid after washing include suction removal, natural drying, heat drying, air drying, reduced pressure drying, and a treatment liquid removal step described later.

C. Process liquid removal process The process liquid removal process in this invention is performed conveying a polarizing film laminated body so that an exposed part may face downward. By conveying the exposed portion downward, the treatment liquid falls according to gravity, so that the removal efficiency of the treatment liquid can be improved and the re-adhesion of the treatment liquid during the removal step can be prevented. Therefore, it can be prevented that the properties and appearance of the obtained polarizer are adversely affected by the remaining or reattachment of the treatment liquid.

  Regarding the conveyance of the polarizing film laminate in the treatment liquid removing step, the conveyance angle is preferably 0 ° (that is, horizontal) to 90 °, and more preferably 0 ° to 45 °. When the angle which conveys a polarizing film laminated body is in said range, the removal efficiency of the processing liquid in an exposure part improves, and it can further prevent reattachment of the processing liquid to an exposure part.

  In one embodiment, a process liquid removal process includes conveying a polarizing film laminated body horizontally so that an exposed part may face down. By horizontally transporting the polarizing film laminate so that the exposed part faces downward, the processing liquid in the exposed part falls according to gravity, and the processing liquid remaining in the exposed part can be more easily removed. Furthermore, since the polarizing film laminate is horizontal, it is possible to satisfactorily prevent re-adhesion of the removed processing liquid to the exposed portion.

  When the polarizing film laminate is transported horizontally so that the exposed portion faces downward, the treatment liquid can be efficiently removed only by transportation, but the removal efficiency of the treatment liquid can be further increased by using any appropriate draining means. It is possible to improve and prevent the treatment liquid from reattaching to the exposed portion. In this case, it is preferable to use any appropriate absorbent material such as cloth, waste or sponge, an air knife, an air blow or the like as the draining means. When transported horizontally so that the exposed portion faces downward, the processing liquid can be efficiently removed by gravity. By combining this conveying method with any appropriate absorbent material, air knife, air blower or other draining means, the removal liquid removed from the exposed part can be appropriately removed by the draining means. It is possible to satisfactorily prevent re-adhesion of the treatment liquid to the surface.

  Moreover, in another embodiment, a process liquid removal process includes carrying out inclination conveyance of the polarizing film laminated body upwards so that an exposed part may face downward. FIG. 5 is a schematic view showing a treatment liquid removal step of the polarizing film laminate performed according to one embodiment of the present invention. The polarizing film laminate 100 can be lifted from the treatment bath while being conveyed upward so that the exposed portion 51 faces downward. When transported in this manner, the processing liquid remaining in the exposed portion can be accumulated on the lower wall surface of the through hole forming the exposed portion even when the processing liquid cannot be discharged outside the exposed portion. Therefore, it is possible to prevent the treatment liquid from reattaching to the surface of the polarizer in the exposed portion. In this case, it is preferable to use any appropriate draining means together with the upward inclined conveyance. FIG. 6 is a schematic view showing a treatment liquid removal step of the polarizing film laminate performed according to another embodiment of the present invention. In this embodiment, the polarizing film laminate 100 is provided with the draining means 400 so that the exposed portion 51 is conveyed downward, and is opposed to the exposed portion. For example, when a blower is used as the draining means 400, by blowing wind from below, it is possible to blow wind from the blower 400 to the processing liquid remaining in the exposed portion and flowing downward according to gravity, and blow off the processing liquid. The treatment liquid removal effect can be further improved.

  Examples of draining means used when the polarizing film laminate is inclined and conveyed upward so that the exposed portion faces downward include a blower, an air blow, an air knife, and the like. This is because by using these draining means, it is possible to remove the processing liquid flowing downward according to gravity, and the processing liquid can be removed satisfactorily.

  Furthermore, in another embodiment, a process liquid removal process includes conveying a polarizing film laminated body horizontally so that an exposed part may face downward, and carrying out slant conveyance upwards. By including these two types of conveyance, the treatment liquid remaining in the exposed portion can be removed better. When two types of conveyance are included, the order of these conveyances is not particularly limited, and these conveyances may be combined a plurality of times. For example, when the polarizing film laminate is transported horizontally so that the exposed portion faces downward, and then inclined transport is performed upward, most of the processing liquid remaining in the exposed portion is removed by gravity by the initial horizontal transport. be able to. Furthermore, the treatment liquid remaining after being transported horizontally can be sufficiently removed by upwardly tilted transport. Further, by performing further horizontal conveyance after the upward inclined conveyance, the treatment liquid adhering to the wall surface below the exposed portion can be dropped according to gravity and can be sufficiently removed from the exposed portion. Further, by repeatedly performing these transport steps, it is possible to further prevent the treatment liquid from remaining in the exposed portion. When these transports are used in combination, draining means suitable for each transport may be further combined. As described above, after removing most of the treatment liquid, the remaining treatment liquid can be efficiently removed, so that the polarizing film laminate is conveyed horizontally so that the exposed portion faces downward, and then the inclined conveyance upwards. It is preferable that the inclined conveyance is performed so that the exposed portion and the draining means face each other.

  Further, the treatment liquid removal step may further include a treatment liquid removal step by means other than those described above. For example, the drying process mentioned later and the process liquid removal process which contacts cloth, waste, and a sponge roll from the surface by the side of the surface protection film of a polarizing film laminated body are mentioned. These steps are preferably performed after the treatment liquid removing step which is performed while transporting so that the exposed portion of the polarizing film laminate is directed downward. In the treatment liquid removal step that is performed while transporting the exposed portion of the polarizing film laminate so as to face downward, when there is a treatment solution that could not be removed, the treatment solution is more sufficiently removed by these other removal steps. Can be removed.

D. Other Steps The production method of the present invention may include any appropriate steps other than those mentioned in the above items A to C. For example, a drying process etc. are mentioned.

  As a drying means, it can carry out by arbitrary appropriate methods. Examples of the drying means include an oven, an air blow, and an air knife. The drying temperature and the drying time can be set to any appropriate values depending on the thickness and characteristics of the polarizing film laminate.

  After the necessary steps are completed, the first surface protective film (and the second surface protective film, if present) can be peeled from the polarizing film laminate.

E. As described above, the production method of the present invention includes a step of wet-treating the long polarizing film laminate and a treatment liquid removal step of removing the treatment liquid used in the wet treatment. . The treatment liquid removing step is performed while conveying the polarizing film laminate so that the exposed portion faces downward. By carrying out the treatment liquid removing process while conveying the exposed portion of the polarizing film laminate downward, the treatment liquid remaining in the exposed portion of the polarizing film laminate is removed and the removed treatment liquid is within the exposed portion. It can be prevented from reattaching to the surface. The treatment liquid remaining on the exposed portion can adversely affect the characteristics and appearance of the exposed portion. However, in the manufacturing method of the present invention, it is possible to prevent the treatment liquid from remaining and re-adhering in the exposed portion, and therefore, it is possible to prevent the adverse effect on the characteristics and appearance of the polarizer, and high quality A polarizer having a polarizing portion may be provided. The polarizer having a non-polarizing portion of the present invention is suitably used for an image display device with a camera (liquid crystal display device, organic EL device) such as a mobile phone such as a smartphone, a notebook PC, or a tablet PC. When applied to these, the non-polarizing part may correspond to the camera hole part of these devices. When the non-polarizing part corresponds to the camera hole part, not only the transparency of the camera hole part is ensured, but also the brightness and color at the time of shooting are optimized, and the image obtained is prevented from being distorted. This can contribute to improving the camera performance of the display device. The polarizer having a non-polarizing part of the present invention is not only a receiving electronic device such as an image or a monitor (for example, a camera device having a photographing optical system), but also a transmitting electronic device such as an LED light or an infrared sensor. It can also be suitably used for an image display device that ensures the transparency to the naked eye and the straightness of light.

  The single transmittance (Ts) of the obtained polarizer (excluding the non-polarized part) is preferably 39% or more, more preferably 39.5% or more, still more preferably 40% or more, and particularly preferably 40.5% or more. It is. The theoretical upper limit of the single transmittance is 50%, and the practical upper limit is 46%. Further, the single transmittance (Ts) is a Y value measured with a 2 degree visual field (C light source) of JIS Z8701 and corrected for visibility, for example, using a microspectroscopic system (Lambda Vision, LVmicro). Can be measured. The degree of polarization of the polarizer (excluding the non-polarized part) is preferably 99.9% or more, more preferably 99.93% or more, and further preferably 99.95% or more.

  The transmittance of the non-polarizing part (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, further preferably 75% or more, Particularly preferably, it is 90% or more. With such transmittance, desired transparency as a non-polarizing portion can be ensured. As a result, when the polarizer is arranged so that the non-polarizing part corresponds to the camera part of the image display device, it is possible to prevent an adverse effect on the photographing performance of the camera.

  Any appropriate shape can be adopted as the planar view shape of the non-polarizing part as long as it does not adversely affect the camera performance of the image display device using the polarizer. The planar view shape of the non-polarizing portion corresponds to the shape of the through hole of the first surface protective film.

  In one embodiment, the absorption axis of the polarizer is substantially parallel to the longitudinal direction or the width direction, and both ends of the polarizer are slit in parallel to the longitudinal direction. With such a configuration, by performing a cutting operation with reference to the end face of the polarizer, a plurality of polarizers having a non-polarizing portion and having an absorption axis in an appropriate direction can be easily manufactured. .

  The polarizer can be provided as a polarizing plate practically. The polarizing plate has a polarizer and a protective film disposed on at least one side of the polarizer (not shown). Practically, the polarizing plate has an adhesive layer as the outermost layer. The pressure-sensitive adhesive layer is typically the outermost layer on the image display device side. A separator is temporarily attached to the pressure-sensitive adhesive layer so as to be peeled off, and the pressure-sensitive adhesive layer is protected until actual use, and roll formation is possible.

  The polarizing plate may further have any appropriate optical functional layer depending on the purpose. Representative examples of the optical functional layer include a retardation film (optical compensation film) and a surface treatment layer. For example, a retardation film can be disposed between the protective film and the pressure-sensitive adhesive layer. The optical characteristics (for example, refractive index ellipsoid, in-plane retardation, thickness direction retardation) of the retardation film can be appropriately set according to the purpose, characteristics of the image display device, and the like. For example, when the image display device is an IPS mode liquid crystal display device, there are a retardation film in which the refractive index ellipsoid is nx> ny> nz and a retardation film in which the refractive index ellipsoid is nz> nx> ny. Can be placed. The retardation film may also serve as a protective film. In this case, the protective film can be omitted. Conversely, the protective film may have an optical compensation function (that is, may have an appropriate refractive index ellipsoid, an in-plane retardation and a thickness direction retardation depending on the purpose). “Nx” is the refractive index in the direction in which the refractive index in the film plane is maximum (ie, the slow axis direction), and “ny” is the refractive index in the direction perpendicular to the slow axis in the film plane. “Nz” is the refractive index in the thickness direction.

  The surface treatment layer may be disposed on the viewing side of the polarizing plate. Typical examples of the surface treatment layer include a hard coat layer, an antireflection layer, and an antiglare layer. For example, the surface treatment layer is preferably a layer having a low moisture permeability for the purpose of improving the humidification durability of the polarizer. The hard coat layer is provided for the purpose of preventing scratches on the surface of the polarizing plate. The hard coat layer can be formed by, for example, a method of adding a cured film excellent in hardness, slipping properties, etc., to an appropriate ultraviolet curable resin such as acrylic or silicone. The hard coat layer preferably has a pencil hardness of 2H or more. The antireflection layer is a low reflection layer provided for the purpose of preventing reflection of external light on the surface of the polarizing plate. As the antireflection layer, for example, a thin layer type for preventing reflection by using a canceling effect of reflected light by the interference action of light as disclosed in JP-A-2005-248173, JP-A-2011-2759 The surface structure type which expresses a low reflectance by giving a fine structure to the surface as disclosed in (1). The antiglare layer is provided for the purpose of preventing external light from being reflected on the surface of the polarizing plate and hindering the viewing of the light transmitted through the polarizing plate. The antiglare layer is formed, for example, by imparting a fine concavo-convex structure to the surface by an appropriate method such as a roughening method by a sandblasting method or an embossing method, or a blending method of transparent fine particles. The antiglare layer may also serve as a diffusion layer (viewing angle expanding function or the like) for diffusing the light transmitted through the polarizing plate to expand the viewing angle. Instead of providing the surface treatment layer, the same surface treatment may be applied to the surface of the protective film on the viewing side.

  The polarizer of the present invention is suitably used for an image display device with a camera (liquid crystal display device, organic EL device) such as a mobile phone such as a smartphone, a notebook PC, or a tablet PC.

DESCRIPTION OF SYMBOLS 10 Polarizer 20 Protective layer 30 2nd surface protective film 50 1st surface protective film 70 Resin film 80 Adhesive layer 100 Polarizing film laminated body 400 Draining means

Claims (5)

A step of wet-treating a long polarizing film laminate comprising a polarizer and a surface protective film disposed on one side of the polarizer, and having an exposed portion where the polarizer is exposed on the one side; A treatment liquid removal step for removing the treatment liquid used in the wet treatment,
The manufacturing method of the polarizer which has a non-polarizing part by which this process liquid removal process is performed, conveying this polarizing film laminated body so that an exposed part may face downward.   The manufacturing method of the polarizer which has a non-polarizing part of Claim 1 whose angle which conveys the polarizing film laminated body in the said process liquid removal process is 0 degree-90 degrees.   The manufacturing method of the polarizer which has a non-polarizing part of Claim 1 or 2 with which the said process liquid removal process includes conveying the said polarizing film laminated body horizontally.   4. The process according to claim 1, wherein the treatment liquid removal step is performed so that the polarizing film laminate is conveyed in an inclined manner, and the exposed portion of the polarizing film laminated body that is inclined and conveyed is opposed to the treatment liquid removing unit. A method for producing a polarizer having a non-polarizing part as described in 1.   The manufacturing method of the polarizer which has a non-polarizing part in any one of Claim 1 to 4 with which the said process liquid removal process is performed in combination with a blower, an air blow, an air knife, and wiping off.

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