WO2019188735A1 - Method for manufacturing polarizer - Google Patents

Method for manufacturing polarizer Download PDF

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Publication number
WO2019188735A1
WO2019188735A1 PCT/JP2019/011952 JP2019011952W WO2019188735A1 WO 2019188735 A1 WO2019188735 A1 WO 2019188735A1 JP 2019011952 W JP2019011952 W JP 2019011952W WO 2019188735 A1 WO2019188735 A1 WO 2019188735A1
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WO
WIPO (PCT)
Prior art keywords
laminate
polarizer
protective film
resin layer
thickness
Prior art date
Application number
PCT/JP2019/011952
Other languages
French (fr)
Japanese (ja)
Inventor
聡司 三田
友斗 猿橋
森　拓也
Original Assignee
日東電工株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 日東電工株式会社 filed Critical 日東電工株式会社
Priority to JP2020509929A priority Critical patent/JP6964181B2/en
Priority to KR1020207024866A priority patent/KR20200136375A/en
Priority to CN201980021084.8A priority patent/CN111902750B/en
Publication of WO2019188735A1 publication Critical patent/WO2019188735A1/en

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B29C55/04—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique
    • B29C55/08—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique transverse to the direction of feed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • B32B27/306—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers comprising vinyl acetate or vinyl alcohol (co)polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/023—Optical properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04—Interconnection of layers
    • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements

Definitions

  • the present invention relates to a method for manufacturing a polarizer.
  • polarizers substantially polarizing plates including a polarizer
  • a polarizer is typically manufactured by dyeing a polyvinyl alcohol (PVA) resin film with a dichroic substance such as iodine (for example, Patent Documents 1 and 2).
  • PVA polyvinyl alcohol
  • iodine for example, Patent Documents 1 and 2.
  • the polarizer is also required to be thinner.
  • process protective films may be used in the manufacture of thin polarizers to prevent such breakage (for example, Patent Documents 3 and 4). ).
  • the process protection film is bonded to a polyvinyl alcohol (PVA) -based resin layer (or a laminate including a PVA-based resin layer) that temporarily forms a polarizer during the manufacturing process of the polarizer, and the surface protection is performed after the polarizer is manufactured.
  • PVA polyvinyl alcohol
  • the film is replaced with a film (the surface protective film is also peeled off when the polarizer is actually used).
  • the process protective film there are problems such as peeling of the process protective film during the manufacturing process and breakage or breakage of the film end due to curling of the polarizer, and breakage of the polarizer when the process protective film is replaced. is there.
  • the present invention has been made to solve the above-mentioned problems, and its main purpose is to peel off the process protective film and the curl of the polarizer during the manufacturing process, and to break the polarizer when the process protective film is replaced.
  • An object of the present invention is to provide a method for manufacturing a prevented thin polarizer.
  • the process protective film is temporarily attached to the substrate side of the laminate including the polyvinyl alcohol-based resin layer and the substrate; and the process protective film is temporarily attached. And dyeing the laminated body to make the polyvinyl alcohol-based resin layer a polarizer.
  • the thickness of the polyvinyl alcohol-based resin layer is 5 ⁇ m or less, the thickness of the base material is 40 ⁇ m or less, and the total thickness T1 of the laminate is 45 ⁇ m or less; (N / 25 mm) or more; the total thickness T1 of the laminate and the thickness T2 of the process protective film satisfy the relationship of the following formula (1): T1 / T2 ⁇ 1.0 (1).
  • the high speed peeling force of the said process protective film is 5 times or less of the said low speed peeling force.
  • the polyvinyl alcohol-based resin layer is stretched before temporarily attaching the process protection film to the laminate.
  • the substrate is an optical functional film.
  • a method for producing a thin polarizer comprising temporarily attaching a process protective film to a laminate comprising a polyvinyl alcohol-based resin layer and a substrate, the thickness of the process protective film and the thickness of the laminate
  • the thickness of the process protective film and the thickness of the laminate By optimizing the relationship with the total thickness and the low-speed peel force of the process protection film, it prevents the process protection film from peeling and the curling of the polarizer during the manufacturing process, and preventing the polarizer from breaking when the process protection film is replaced. can do.
  • a thin polarizer can be manufactured efficiently.
  • A. Manufacturing method of polarizer A-1. Outline of Method for Producing Polarizer A method for producing a polarizer according to an embodiment of the present invention involves temporarily attaching a process protective film to a substrate side of a laminate including a polyvinyl alcohol (PVA) resin layer and a substrate. And dyeing the laminate (substantially the PVA resin layer) to which the process protective film is temporarily attached, and using the PVA resin layer as a polarizer.
  • PVA polyvinyl alcohol
  • the manufacturing method includes a step of preparing a laminate including a PVA-based resin layer and a base material, a process protective film temporary attachment process, a stretching process, a dyeing process, a swelling process, a crosslinking process, a washing process, It includes a drying step and a step of removing the step protective film (a step of replacing the step protective film with the surface protective film).
  • a process in which the laminate is provided can be performed in any appropriate order and timing except that the dyeing process, the crosslinking process, and the drying process are performed after the temporary attachment process of the process protective film. Accordingly, the steps may be performed in the order described above, or may be performed in an order different from the above. If necessary, one step may be performed a plurality of times. Furthermore, you may perform processes (for example, insolubilization process) other than the above at arbitrary appropriate timings.
  • the thickness of the PVA-based resin layer of the laminate to which the process protective film is temporarily attached is 5 ⁇ m or less, preferably 4 ⁇ m or less, more preferably 3 ⁇ m or less, and further preferably 2 ⁇ m. Or less, particularly preferably 1.5 ⁇ m or less.
  • the thickness of the PVA resin layer is preferably 0.5 ⁇ m or more, more preferably 0.6 ⁇ m or more, and further preferably 0.8 ⁇ m or more.
  • the thickness of the base material of the laminated body on which the process protective film is temporarily attached is 40 ⁇ m or less, preferably 35 ⁇ m or less, more preferably 30 ⁇ m or less.
  • the thickness of the substrate can be, for example, 15 ⁇ m or more.
  • the total thickness T1 of the laminate on which the process protection film is temporarily attached is 45 ⁇ m or less, preferably 40 ⁇ m or less, and more preferably 35 ⁇ m or less.
  • the total thickness T1 of the laminate may be, for example, 16 ⁇ m or more.
  • the total thickness T1 of the laminate on which the process protection film is temporarily attached and the thickness T2 of the process protection film satisfy the relationship of the following formula (1): T1 / T2 ⁇ 1.0 (1).
  • T1 / T2 is preferably 0.95 or less, and more preferably 0.90 or less.
  • T1 / T2 can be, for example, 0.30 or more. If T1 / T2 is in such a range, even if a polarizer is produced from a very thin PVA resin layer using a process protective film, a polarizer (substantially laminated) Body) can be satisfactorily prevented.
  • the thickness T2 of the process protective film any appropriate thickness can be adopted as long as the desired T1 / T2 is realized.
  • the thickness T2 of the process protection film is, for example, 30 ⁇ m to 100 ⁇ m, preferably 35 ⁇ m to 80 ⁇ m.
  • the low-speed peel force of the process protective film is 0.12 (N / 25 mm) or more, preferably 0.14 (N / 25 mm) or more.
  • the low speed peeling force of the process protection film can be, for example, 0.25 (N / 25 mm) or less. If the low-speed peel force of the process protective film is in such a range, even if a polarizer is produced from a very thin PVA-based resin layer using the process protective film, the polarizer in the manufacturing process (substantially Therefore, curling of the laminate can be prevented satisfactorily.
  • the high speed peel force of the process protective film is preferably 5 times or less, more preferably 4 times or less, and further preferably 3 times or less of the above low speed peel force.
  • the high speed peeling force of the process protective film is preferably 0.8 times or more, more preferably 1.0 times or more of the above low speed peeling force. If the ratio of the high-speed peeling force to the low-speed peeling force of the process protective film is within such a range, the process protective film can be effectively prevented while curling the polarizer (substantially a laminate) during the production process. It is possible to satisfactorily prevent the polarizer from being broken when it is peeled off.
  • the process protection film typically includes a main body film and an adhesive layer.
  • the low speed peel force and the high speed peel force of the process protective film can be controlled by adjusting the constituent material and thickness of the main body film and the constituent material and thickness of the pressure-sensitive adhesive layer.
  • the peeling force can be measured according to JIS Z 0237. Specifically, the peeling force is defined as a force when the process protection film is cut into a length of 120 mm and a width of 25 mm to form a measurement sample, and the measurement sample is peeled at an angle of 180 °.
  • “low speed peel force” refers to the peel force when the peel speed is 300 mm / min in the above measurement
  • “high speed peel force” refers to the peel force when the peel speed is 30000 mm / min.
  • Laminate The laminate includes a PVA resin layer and a substrate as described above.
  • PVA-based resin layer examples include polyvinyl alcohol and ethylene-vinyl alcohol copolymer.
  • Polyvinyl alcohol is obtained by saponifying polyvinyl acetate.
  • the ethylene-vinyl alcohol copolymer can be obtained by saponifying an ethylene-vinyl acetate copolymer.
  • the saponification degree of the PVA resin is usually 85 mol% or more and less than 100 mol%, preferably 95.0 mol% to 99.95 mol%, more preferably 99.0 mol% to 99.93 mol%. is there.
  • the degree of saponification can be determined according to JIS K 6726-1994. By using a PVA-based resin having such a saponification degree, a polarizer having excellent durability can be obtained. If the degree of saponification is too high, there is a risk of gelation.
  • the average degree of polymerization of the PVA resin can be appropriately selected according to the purpose.
  • the average degree of polymerization is usually 1000 to 10,000, preferably 1200 to 4500, and more preferably 1500 to 4300.
  • the average degree of polymerization can be determined according to JIS K 6726-1994.
  • the PVA resin layer may be formed by laminating a PVA resin film and a base material, or may be formed by applying and drying a coating liquid containing the PVA resin on the base material.
  • the substrate may be a substrate used only for the production of a polarizer (a substrate for producing a polarizer) or an optical functional film. Good.
  • the substrate is a substrate for preparing a polarizer, the substrate is typically peeled off after the polarizer is manufactured.
  • a base material is an optical function film, the said base material can be used as it is, without peeling even after polarizer production.
  • the substrate is an optical functional film, (i) a PVA-based resin layer is formed on the optical functional film to produce a laminate, and a process protective film is temporarily attached to the optical functional film side of the laminate.
  • the optical functional film is bonded to the PVA-based resin layer side of the laminate including the PVA-based resin layer and the polarizer-forming substrate, and the polarizer-producing substrate / PVA-based resin layer / optical
  • a laminated body of functional films is produced, and a substrate for preparing a polarizer is peeled and removed from the laminated body to produce a laminated body of PVA-based resin layer / optical functional film, and process protection is provided on the optical functional film side of the laminated body.
  • a film may be temporarily attached.
  • thermoplastic resin When the base material is a base material for producing a polarizer, any appropriate thermoplastic resin can be adopted as a constituent material of the base material.
  • the thermoplastic resin 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. Is mentioned.
  • Preferred are norbornene resins and amorphous polyethylene terephthalate resins. An amorphous (non-crystallized) polyethylene terephthalate resin is preferable, and an amorphous (hard to crystallize) polyethylene terephthalate resin is more preferable.
  • the substrate is an optical functional film
  • the optical functional film include a retardation film, a polarizer protective film, and a brightness enhancement film.
  • the stretching direction may be the longitudinal direction (MD direction) of the laminate, or the width direction (TD direction) of the laminate.
  • the stretching method may be dry stretching, wet stretching, or a combination thereof.
  • the stretching direction can correspond to the absorption axis direction of the obtained polarizer.
  • the PVA resin layer is stretched before temporarily attaching the process protection film to the laminate. Therefore, the thickness of the PVA-based resin layer described in the above section A-1 is typically a thickness after stretching, and may be equal to the thickness of the finally obtained polarizer.
  • a PVA-based resin layer is formed on the optical functional film to produce a laminate, the laminate is stretched, and a process protective film is temporarily attached to the optical functional film side of the stretched laminate.
  • a laminate including a PVA resin layer and a polarizer preparation substrate is stretched, and an optical functional film is bonded to the PVA resin layer side of the stretched laminate to produce a polarizer.
  • a laminate of the base material / PVA resin layer / optical functional film is prepared, and the polarizer preparation base material is peeled off from the laminate to prepare a laminate of PVA resin layer / optical functional film.
  • a process protective film may be temporarily attached to the optical functional film side of the body.
  • a PVA-based resin layer is formed on the optical functional film precursor to produce a laminate, and the laminate is stretched to stretch the PVA-based resin layer and to convert the optical functional film from the optical functional film precursor.
  • a laminate of PVA resin layer / optical functional film may be produced.
  • Such a configuration is suitable when the optical functional film is a retardation film.
  • A-4. Swelling process The swelling process is usually performed before the dyeing process.
  • a swelling process is performed by immersing a laminated body (substantially PVA-type resin layer) in a swelling bath, for example.
  • a swelling bath water such as distilled water or pure water is usually used.
  • the swelling bath may contain any appropriate other component other than water. Examples of other components include alcohols and other solvents, surfactants and other additives, and iodides.
  • Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, and titanium iodide. Etc. Preferably, potassium iodide is used.
  • the temperature of the swelling bath is, for example, 20 ° C. to 45 ° C.
  • the immersion time is, for example, 10 seconds to 300 seconds.
  • Process Protection Film Temporary Attachment Process The process protection film temporary attachment process is performed before the dyeing process as described in the above section A-1.
  • the thickness and peeling force of the process protective film are as described in the above section A-1.
  • the thickness of a process protection film is the thickness of a main body film.
  • main film As a constituent material of the process protection film (main film), a material having a high Young's modulus is preferable. This is because a so-called strong film can be realized.
  • the Young's modulus of the process protective film is preferably 1000 MPa or more.
  • the constituent material of the process protective film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polypropylene (PP), and cycloolefin resin (COP).
  • PET polyethylene terephthalate
  • PEN polyethylene naphthalate
  • PP polypropylene
  • COP cycloolefin resin
  • the pressure-sensitive adhesive for the process protective film does not contain either an antistatic agent or a surfactant, or both. With such an adhesive, contamination of the dyeing bath and / or crosslinking bath due to elution can be prevented, and a polarizer having no variation in quality can be obtained.
  • the dyeing process is performed after the temporary attachment process of the process protective film as described in the above section A-1.
  • the dyeing step is a step of dyeing the PVA resin layer with a dichroic substance. Preferably, it is carried out by adsorbing a dichroic substance.
  • adsorption method for example, a method of immersing a laminate (substantially, a PVA resin layer) in a staining solution containing a dichroic substance, or a method of immersing the laminate (substantially, a PVA resin layer)
  • a method of immersing the laminate substantially, a PVA resin layer
  • examples thereof include a method of applying a staining solution, a method of spraying the staining solution onto a laminate (substantially, a PVA resin layer), and the like.
  • it is a method of immersing the laminate (substantially, the PVA resin layer) in the dyeing solution. It is because a dichroic substance can adsorb
  • the dichroic substance examples include iodine and dichroic dyes. Preferably, it is iodine.
  • iodine is used as the dichroic substance
  • an aqueous iodine solution is preferably used as the staining solution.
  • the iodine content of the aqueous iodine solution is preferably 0.04 to 5.0 parts by weight with respect to 100 parts by weight of water.
  • an iodide As the iodide, potassium iodide is preferably used.
  • the iodide content is preferably 0.3 to 15 parts by weight with respect to 100 parts by weight of water.
  • the liquid temperature during staining of the staining liquid can be set to any appropriate value, for example, 20 ° C. to 50 ° C.
  • the immersion time is, for example, 5 seconds to 5 minutes.
  • a boron compound is usually used as a crosslinking agent.
  • the boron compound include boric acid and borax. Preferably, it is a boric acid.
  • the boron compound is usually used in the form of an aqueous solution.
  • the boric acid concentration of the boric acid aqueous solution is, for example, 1% by weight to 15% by weight, and preferably 1% by weight to 10% by weight.
  • the boric acid aqueous solution may further contain an iodide such as potassium iodide, or a zinc compound such as zinc sulfate or zinc chloride.
  • the crosslinking step can be performed by any appropriate method.
  • a method of immersing a laminate (substantially, a PVA resin layer) in an aqueous solution containing a boron compound a method of applying an aqueous solution containing a boron compound to a laminate (substantially, a PVA resin layer), Or the method of spraying the aqueous solution containing a boron compound on a laminated body (substantially PVA-type resin layer) is mentioned. It is preferable to immerse in an aqueous solution containing a boron compound.
  • the temperature of the solution used for crosslinking is, for example, 25 ° C. or higher, preferably 30 ° C. to 85 ° C., more preferably 40 ° C. to 70 ° C.
  • the immersion time is, for example, 5 seconds to 800 seconds, and preferably 8 seconds to 500 seconds.
  • washing step can typically be performed after the crosslinking step.
  • the cleaning step is typically performed by immersing the laminate in a cleaning solution.
  • a typical example of the cleaning liquid is pure water. Potassium iodide may be added to pure water.
  • the temperature of the cleaning liquid is, for example, 5 ° C to 50 ° C.
  • the immersion time is, for example, 1 second to 300 seconds.
  • the drying step can be performed by any appropriate method. Examples of the drying method include natural drying, air drying, reduced pressure drying, and heat drying. Heat drying is preferably used. In the case of performing heat drying, the heating temperature is, for example, 30 ° C. to 100 ° C. The drying time is, for example, 20 seconds to 10 minutes. The drying may be performed in multiple stages (for example, two stages).
  • a polarizer can be produced on the substrate. Thereafter, an adhesive application step or the like may be performed before the process protective film is removed.
  • Step Protection Film Removal After the production of the polarizer, the step protection film is removed (typically peeled off). Typically, after the process protective film is peeled off, the surface protective film is bonded to the peeled surface. That is, after the polarizer is produced, the process protection film is replaced with a surface protection film. When the base material of the laminate is peeled and removed, the optical functional film is bonded to the opposite side of the base material (and the process protection film) of the laminate, and then the process protection film and the base material are peeled from the laminate. The surface protective film is bonded to the release surface.
  • the iodine content of the polarizer obtained by the production method of the present invention can be appropriately set according to the thickness of the polarizer from the viewpoint of providing sufficient polarization performance and optimum transmittance.
  • the iodine content is preferably 5.0 wt% to 13.0 wt%; when the thickness of the polarizer is 3 ⁇ m or less
  • the iodine content is preferably 10.0% to 25.0% by weight.
  • the “iodine content” means the amount of all iodine contained in the polarizer (PVA resin layer).
  • Iodine exists in the form of iodine ions (I ⁇ ), iodine molecules (I 2 ), polyiodine ions (I 3 ⁇ , I 5 ⁇ ), etc. in the polarizer.
  • Iodine content means the amount of iodine encompassing all these forms.
  • the iodine content can be calculated, for example, by a calibration curve method of fluorescent X-ray analysis.
  • the polarizer obtained by the production method of the present invention is typically used in a state where a protective film is laminated on one side or both sides thereof (that is, as a polarizer). 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.
  • any appropriate resin film is used as the protective film.
  • the resin film forming material include (meth) acrylic resins, cellulose resins such as diacetyl cellulose and triacetyl cellulose, cycloolefin resins such as norbornene resins, olefin resins such as polypropylene, and polyethylene terephthalate resins. And ester resins such as polyamide resins, polycarbonate resins, and copolymer resins thereof.
  • the “(meth) acrylic resin” refers to an acrylic resin and / or a methacrylic resin.
  • the present invention will be specifically described by way of examples, but the present invention is not limited to these examples.
  • the measuring method of each characteristic is as follows.
  • peeling force Measured according to JIS Z 0237 The Specifically, the process protective film used in the examples and comparative examples was cut into a length of 120 mm and a width of 25 mm to obtain a measurement sample. The measurement sample was affixed to the substrate side of the laminate of the substrate / polarizer obtained in the examples and comparative examples, and a tensile tester (product name “TE-702 high-speed peel tester” manufactured by Tester Sangyo Co., Ltd.). ) was used to measure the peel force when peeled at a peel angle of 180 °. For the low speed peel force, the peel force was measured when the peel speed was 300 mm / min.
  • the high-speed peeling force measured the peeling force when the peeling speed was 30000 mm / min.
  • Peeling of process protective film In the production methods of Examples and Comparative Examples, the presence or absence of peeling of the process protective film was confirmed by visual observation and evaluated according to the following criteria. The presence or absence of peeling was confirmed at two points after the crosslinking step and after the drying step. ⁇ : No peeling is observed ⁇ : Peeling is recognized (3) Curl In the production methods of Examples and Comparative Examples, the process protective film / substrate / polarizer after the drying process (that is, from the drying oven) The amount of warpage in the width direction (TD) of the laminate was measured and evaluated according to the following criteria.
  • Warpage amount is less than 50 mm
  • Warpage amount is 50 mm or more (4) Breaking
  • the conveyance speed after the cleaning step was set to 20 m / min or more.
  • the presence or absence of breakage of the laminate (polarizing plate) when the process protective film was peeled off after the drying process was visually confirmed and evaluated according to the following criteria. ⁇ : No breakage is observed
  • the obtained pressure-sensitive adhesive composition was applied to a 38 ⁇ m PET film (manufactured by Mitsubishi Chemical Polyester, T100) so that the thickness after drying was 5 ⁇ m, and dried at 130 ° C. for 1 minute to form a pressure-sensitive adhesive layer.
  • the process protection film A which has the structure of a main body film (PET film) / adhesive layer was produced.
  • the low speed peel force of the process protective film A was 0.14 (N / 25 mm), and the high speed peel force was 0.17 (N / 25 mm).
  • a process protective film B was produced in the same manner as in Production Example 1 except that Mitsubishi Chemical Polyester “T100-75” (thickness 75 ⁇ m) was used as the main body film (PET film).
  • the low speed peel force of the process protective film B was 0.12 (N / 25 mm), and the high speed peel force was 0.45 (N / 25 mm).
  • a commercially available PET film with a pressure-sensitive adhesive layer (manufactured by Fujimori Kogyo Co., Ltd., product name “AS3-304”, main body film thickness 38 ⁇ m, pressure-sensitive adhesive layer thickness 20 ⁇ m) was used as it was as a process protective film C.
  • the low speed peel force of the process protective film C was 0.11 (N / 25 mm), and the high speed peel force was 2.20 (N / 25 mm).
  • the obtained acrylic polymer solution (40% by weight) was diluted to 20% by weight with ethyl acetate, and polyoxyethylene nonylphenyl as a surfactant having an aromatic ring with respect to 100 parts by weight of the solid content in this solution.
  • Ammonium ether sulfate (trade name “Hitenol N-08”, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 0.1 parts by weight, hexamethylene diisocyanate isocyanurate as a crosslinking agent (trade name “Coronate HX”, manufactured by Nippon Polyurethane Industry Co., Ltd.) 5 parts by weight and 0.03 part by weight of dibutyltin dilaurate (trade name “OL-1”, manufactured by Tokyo Fine Chemical Co., Ltd.) were added as a crosslinking catalyst.
  • a process protective film D was produced in the same manner as in Production Example 1 except that a pressure-sensitive adhesive layer having a thickness of 10 ⁇ m was formed using this pressure-sensitive adhesive composition.
  • the low speed peel force of the process protective film D was 0.09 (N / 25 mm), and the high speed peel force was 1.23 (N / 25 mm).
  • Process protective film E A commercially available self-adhesive polyethylene film (manufactured by Toray Film Processing Co., Ltd., product name “Tretec # 30 7332”, thickness of main body film 30 ⁇ m) was used as it was and was designated as process protective film E.
  • the low speed peel force of the process protective film E was 0.08 (N / 25 mm), and the high speed peel force was 0.07 (N / 25 mm).
  • thermoplastic resin substrate an amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 ⁇ m) having a water absorption of 0.75% and Tg of 75 ° C. was used.
  • IPA copolymerized PET film thickness: 100 ⁇ m
  • One side of the substrate was subjected to corona treatment, and polyvinyl alcohol (degree of polymerization 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (degree of polymerization 1200, degree of acetoacetyl modification 4.6) were applied to this corona-treated surface.
  • a saponification degree of 99.0 mol% or more, an aqueous solution containing 9: 1 ratio of Nippon Gosei Kagaku Kogyo Co., Ltd., trade name “Gosefimer Z200”) was applied and dried at 25 ° C. to a thickness of 11 ⁇ m.
  • a PVA resin layer was formed to prepare a laminate. The obtained laminate was stretched in the air 4.5 times in a direction perpendicular to the longitudinal direction of the laminate at 140 ° C. using a tenter stretching machine (stretching treatment). By the said extending
  • the laminated body which has the structure of the process protective film A / base material / PVA type-resin layer was bonded together to the base material side of this laminated body, and the process protective film A of the manufacture example 1 was bonded together.
  • the obtained laminate was immersed in a dyeing bath (an aqueous solution having an iodine concentration of 1.4% by weight and a potassium iodide concentration of 9.8% by weight) at a liquid temperature of 25 ° C. for 12 seconds and dyed (dyeing treatment).
  • a cleaning bath pure water
  • a crosslinking bath an aqueous solution having a boron concentration of 1% by weight and a potassium iodide concentration of 1% by weight
  • crosslinking treatment an aqueous solution having a boron concentration of 1% by weight and a potassium iodide concentration of 1% by weight
  • the laminate was immersed for 3 seconds in a washing bath (aqueous solution having a potassium iodide concentration of 1% by weight) having a liquid temperature of 25 ° C. (second washing treatment).
  • the laminate was dried in an oven at 60 ° C. for 21 seconds (first drying treatment), and further dried in an oven at 50 ° C. for 60 seconds (second drying treatment).
  • Example 2 A laminate having the structure of a base material / PVA resin layer (thickness 6 ⁇ m) was produced in the same manner as in Example 1, and this laminate was stretched in the same manner as in Example 1 to obtain a base material / PVA resin layer (thickness). A laminate having a structure of 1.2 ⁇ m) was produced. A brightness enhancement film (manufactured by Nitto Denko Corporation, product name “APF-V3”) is bonded to the PVA resin layer side of the laminate, and then the substrate is peeled and removed to obtain a brightness enhancement film / PVA resin layer ( A laminate having a thickness of 1.2 ⁇ m was produced.
  • a brightness enhancement film manufactured by Nitto Denko Corporation, product name “APF-V3”
  • a laminate having the structure of a brightness enhancement film / polarizer (thickness: 1.2 ⁇ m) was produced in the same manner as in Example 1 except that this laminate was used.
  • the obtained laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.
  • Example 3 A laminate having the structure of substrate / polarizer (thickness 2.5 ⁇ m) was produced in the same manner as in Example 1 except that the process protective film B of Production Example 2 was used. The obtained laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.
  • Example 1 Except having used the process protection film C of the manufacture example 3, it carried out similarly to Example 1, and produced the laminated body which has a structure of a base material / polarizer (thickness 2.5 micrometers). The obtained laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.
  • Example 2 A laminate having the structure of a substrate / polarizer (thickness: 2.5 ⁇ m) was produced in the same manner as in Example 1 except that the process protective film D of Production Example 4 was used. The obtained laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.
  • Example 3 A laminate having the structure of a base material / polarizer (thickness: 2.5 ⁇ m) was produced in the same manner as in Example 1 except that the process protective film E of Production Example 5 was used. The obtained laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.
  • Example 4 A laminate having the structure of substrate / polarizer (thickness: 2.5 ⁇ m) was produced in the same manner as in Example 1 except that the process protective film was not used. The obtained laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.
  • Polarizers obtained by the manufacturing method of the present invention are used for liquid crystal panels such as liquid crystal televisions, liquid crystal displays, mobile phones, digital cameras, video cameras, portable game machines, car navigation systems, copy machines, printers, fax machines, watches, and microwave ovens. Can be widely applied to.

Abstract

Provided is a method which is for manufacturing a thin polarizer and which prevents the peeling-off of a process protection film and curling of the polarizer during a manufacturing process, and also prevents fracturing of the polarizer during the reattachment of the process protection film. This method for manufacturing a polarizer comprises: temporarily attaching a process protection film to a substrate side of a laminate including a polyvinyl alcohol-based resin layer and a substrate so that the process protection film can be peeled off; and dyeing the laminate to which the process protection film is temporarily attached, and making the polyvinyl alcohol-based resin layer a polarizer. The thickness of the polyvinyl alcohol-based resin layer is 5 μm or less, the thickness of the substrate is 40 μm or less, and the total thickness T1 of the laminate is 45 μm or less; the low-speed peeling force of the process protection film is 0.12 (N/25mm) or more; and the total thickness T1 of the laminate and the thickness T2 of the process protection film satisfy the relationship of expression (1): T1/T2≤1.0∙∙∙(1).

Description

偏光子の製造方法Manufacturing method of polarizer
　本発明は、偏光子の製造方法に関する。 The present invention relates to a method for manufacturing a polarizer.
　代表的な画像表示装置である液晶表示装置には、その画像形成方式に起因して、液晶セルの両側に偏光子（実質的には、偏光子を含む偏光板）が配置されている。偏光子は、代表的には、ポリビニルアルコール（ＰＶＡ）系樹脂フィルムをヨウ素等の二色性物質で染色することにより製造される（例えば、特許文献１および２）。近年、画像表示装置の薄型化の要望が高まっている。そのため、偏光子についても、さらなる薄型化が求められている。しかし、偏光子が薄くなればなるほど製造時に破断しやすいので、薄い偏光子の製造においてはそのような破断を防止するためにいわゆる工程保護フィルムが用いられる場合がある（例えば、特許文献３および４）。工程保護フィルムは、偏光子の製造工程の間一時的に偏光子を形成するポリビニルアルコール（ＰＶＡ）系樹脂層（またはＰＶＡ系樹脂層を含む積層体）に貼り合わせられ、偏光子作製後に表面保護フィルムに貼り換えられる（表面保護フィルムもまた、偏光子の実際の使用時には剥離除去される）。このような工程保護フィルムの使用においては、製造工程中の工程保護フィルムの剥がれおよび偏光子のカールによるフィルム端部の破損や破断、ならびに工程保護フィルムの貼り換え時の偏光子の破断という問題がある。 In a liquid crystal display device, which is a typical image display device, polarizers (substantially polarizing plates including a polarizer) are arranged on both sides of a liquid crystal cell due to the image forming method. A polarizer is typically manufactured by dyeing a polyvinyl alcohol (PVA) resin film with a dichroic substance such as iodine (for example, Patent Documents 1 and 2). In recent years, there has been an increasing demand for thinner image display devices. For this reason, the polarizer is also required to be thinner. However, since the thinner the polarizer, the easier it is to break during manufacturing, so-called process protective films may be used in the manufacture of thin polarizers to prevent such breakage (for example, Patent Documents 3 and 4). ). The process protection film is bonded to a polyvinyl alcohol (PVA) -based resin layer (or a laminate including a PVA-based resin layer) that temporarily forms a polarizer during the manufacturing process of the polarizer, and the surface protection is performed after the polarizer is manufactured. The film is replaced with a film (the surface protective film is also peeled off when the polarizer is actually used). In the use of such a process protective film, there are problems such as peeling of the process protective film during the manufacturing process and breakage or breakage of the film end due to curling of the polarizer, and breakage of the polarizer when the process protective film is replaced. is there.
特許第５０４８１２０号公報Japanese Patent No. 5048120 特開２０１３－１５６３９１号公報JP 2013-156391 A 特開２０１２－１３３２９５号公報JP 2012-133295 A 特開２０１２－１３３２９６号公報JP 2012-133296 A
　本発明は上記課題を解決するためになされたものであり、その主たる目的は、製造工程中の工程保護フィルムの剥がれおよび偏光子のカール、ならびに工程保護フィルムの貼り換え時の偏光子の破断が防止された薄型偏光子の製造方法を提供することにある。 The present invention has been made to solve the above-mentioned problems, and its main purpose is to peel off the process protective film and the curl of the polarizer during the manufacturing process, and to break the polarizer when the process protective film is replaced. An object of the present invention is to provide a method for manufacturing a prevented thin polarizer.
　本発明の偏光子の製造方法は、ポリビニルアルコール系樹脂層と基材とを含む積層体の該基材側に工程保護フィルムを剥離可能に仮着すること；および、該工程保護フィルムが仮着された積層体を染色して、該ポリビニルアルコール系樹脂層を偏光子とすること；を含む。該ポリビニルアルコール系樹脂層の厚みは５μｍ以下であり、該基材の厚みは４０μｍ以下であり、該積層体の総厚みＴ１は４５μｍ以下であり；該工程保護フィルムの低速剥離力は０．１２（Ｎ／２５ｍｍ）以上であり；該積層体の総厚みＴ１と該工程保護フィルムの厚みＴ２とは下記式（１）の関係を満たす：
　　　　Ｔ１／Ｔ２≦１．０　　・・・（１）。
　１つの実施形態においては、上記工程保護フィルムの高速剥離力は、上記低速剥離力の５倍以下である。
　１つの実施形態においては、上記ポリビニルアルコール系樹脂層は、上記工程保護フィルムを上記積層体に仮着する前に延伸されている。
　１つの実施形態においては、上記基材は光学機能フィルムである。 In the method for producing a polarizer of the present invention, the process protective film is temporarily attached to the substrate side of the laminate including the polyvinyl alcohol-based resin layer and the substrate; and the process protective film is temporarily attached. And dyeing the laminated body to make the polyvinyl alcohol-based resin layer a polarizer. The thickness of the polyvinyl alcohol-based resin layer is 5 μm or less, the thickness of the base material is 40 μm or less, and the total thickness T1 of the laminate is 45 μm or less; (N / 25 mm) or more; the total thickness T1 of the laminate and the thickness T2 of the process protective film satisfy the relationship of the following formula (1):
T1 / T2 ≦ 1.0 (1).
In one embodiment, the high speed peeling force of the said process protective film is 5 times or less of the said low speed peeling force.
In one embodiment, the polyvinyl alcohol-based resin layer is stretched before temporarily attaching the process protection film to the laminate.
In one embodiment, the substrate is an optical functional film.
　本発明の製造方法によれば、ポリビニルアルコール系樹脂層と基材とを含む積層体に工程保護フィルムを仮着することを含む薄型偏光子の製造方法において、工程保護フィルムの厚みと積層体の総厚みとの関係ならびに工程保護フィルムの低速剥離力を最適化することにより、製造工程中の工程保護フィルムの剥がれおよび偏光子のカール、ならびに工程保護フィルムの貼り換え時の偏光子の破断を防止することができる。その結果、薄型偏光子を効率よく製造することができる。 According to the production method of the present invention, in a method for producing a thin polarizer comprising temporarily attaching a process protective film to a laminate comprising a polyvinyl alcohol-based resin layer and a substrate, the thickness of the process protective film and the thickness of the laminate By optimizing the relationship with the total thickness and the low-speed peel force of the process protection film, it prevents the process protection film from peeling and the curling of the polarizer during the manufacturing process, and preventing the polarizer from breaking when the process protection film is replaced. can do. As a result, a thin polarizer can be manufactured efficiently.
　以下、本発明の実施形態について説明するが、本発明はこれらの実施形態には限定されない。 Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments.
Ａ．偏光子の製造方法
Ａ－１．偏光子の製造方法の概略
　本発明の実施形態による偏光子の製造方法は、ポリビニルアルコール（ＰＶＡ）系樹脂層と基材とを含む積層体の基材側に工程保護フィルムを剥離可能に仮着すること；および、工程保護フィルムが仮着された積層体（実質的には、ＰＶＡ系樹脂層）を染色して、ＰＶＡ系樹脂層を偏光子とすること；を含む。代表的には、当該製造方法は、ＰＶＡ系樹脂層と基材とを含む積層体を準備する工程、工程保護フィルムの仮着工程、延伸工程、染色工程、膨潤工程、架橋工程、洗浄工程、乾燥工程、および、工程保護フィルムの除去工程（工程保護フィルムから表面保護フィルムへの貼り換え工程）を含む。積層体が供される各工程は、染色工程、架橋工程および乾燥工程が工程保護フィルムの仮着工程の後に行われること以外は、任意の適切な順序およびタイミングで行われ得る。したがって、各工程を上記の順序で行ってもよく、上記とは異なる順序で行ってもよい。必要に応じて、１つの工程を複数回行ってもよい。さらに、上記以外の工程（例えば、不溶化工程）を任意の適切なタイミングで行ってもよい。 A. Manufacturing method of polarizer A-1. Outline of Method for Producing Polarizer A method for producing a polarizer according to an embodiment of the present invention involves temporarily attaching a process protective film to a substrate side of a laminate including a polyvinyl alcohol (PVA) resin layer and a substrate. And dyeing the laminate (substantially the PVA resin layer) to which the process protective film is temporarily attached, and using the PVA resin layer as a polarizer. Typically, the manufacturing method includes a step of preparing a laminate including a PVA-based resin layer and a base material, a process protective film temporary attachment process, a stretching process, a dyeing process, a swelling process, a crosslinking process, a washing process, It includes a drying step and a step of removing the step protective film (a step of replacing the step protective film with the surface protective film). Each process in which the laminate is provided can be performed in any appropriate order and timing except that the dyeing process, the crosslinking process, and the drying process are performed after the temporary attachment process of the process protective film. Accordingly, the steps may be performed in the order described above, or may be performed in an order different from the above. If necessary, one step may be performed a plurality of times. Furthermore, you may perform processes (for example, insolubilization process) other than the above at arbitrary appropriate timings.
　本発明の実施形態においては、工程保護フィルムが仮着される積層体のＰＶＡ系樹脂層の厚みは５μｍ以下であり、好ましくは４μｍ以下であり、より好ましくは３μｍ以下であり、さらに好ましくは２μｍ以下であり、特に好ましくは１．５μｍ以下である。当該ＰＶＡ系樹脂層の厚みは、好ましくは０．５μｍ以上であり、より好ましくは０．６μｍ以上であり、さらに好ましくは０．８μｍ以上である。本発明の実施形態によれば、工程保護フィルムを用いてこのように非常に薄いＰＶＡ系樹脂層から偏光子を作製する場合であっても、製造工程中の工程保護フィルムの剥がれおよび偏光子（実質的には、積層体）のカール、ならびに工程保護フィルムの貼り換え時の偏光子の破断を防止することができる。結果として、非常に薄い偏光子を効率よく製造することができる。さらに、工程保護フィルムが仮着される積層体の基材の厚みは４０μｍ以下であり、好ましくは３５μｍ以下であり、より好ましくは３０μｍ以下である。当該基材の厚みは、例えば１５μｍ以上であり得る。さらに、工程保護フィルムが仮着される積層体の総厚みＴ１は４５μｍ以下であり、好ましくは４０μｍ以下であり、より好ましくは３５μｍ以下である。当該積層体の総厚みＴ１は、例えば１６μｍ以上であり得る。当該基材の厚みおよび当該積層体の総厚みＴ１をこのような範囲とすることにより、所望のＴ１／Ｔ２（後述）を容易に実現することができる。 In the embodiment of the present invention, the thickness of the PVA-based resin layer of the laminate to which the process protective film is temporarily attached is 5 μm or less, preferably 4 μm or less, more preferably 3 μm or less, and further preferably 2 μm. Or less, particularly preferably 1.5 μm or less. The thickness of the PVA resin layer is preferably 0.5 μm or more, more preferably 0.6 μm or more, and further preferably 0.8 μm or more. According to the embodiment of the present invention, even when a polarizer is produced from such a very thin PVA-based resin layer using a process protective film, peeling of the process protective film during the production process and the polarizer ( Substantially, the curling of the laminate) and the breakage of the polarizer when the process protection film is replaced can be prevented. As a result, a very thin polarizer can be efficiently manufactured. Furthermore, the thickness of the base material of the laminated body on which the process protective film is temporarily attached is 40 μm or less, preferably 35 μm or less, more preferably 30 μm or less. The thickness of the substrate can be, for example, 15 μm or more. Furthermore, the total thickness T1 of the laminate on which the process protection film is temporarily attached is 45 μm or less, preferably 40 μm or less, and more preferably 35 μm or less. The total thickness T1 of the laminate may be, for example, 16 μm or more. By setting the thickness of the base material and the total thickness T1 of the laminate in such a range, desired T1 / T2 (described later) can be easily realized.
　さらに、本発明の実施形態においては、工程保護フィルムが仮着される積層体の総厚みＴ１と工程保護フィルムの厚みＴ２とは下記式（１）の関係を満たす：
　　　　Ｔ１／Ｔ２≦１．０　　・・・（１）。
Ｔ１／Ｔ２は、好ましくは０．９５以下であり、より好ましくは０．９０以下である。Ｔ１／Ｔ２は、例えば０．３０以上であり得る。Ｔ１／Ｔ２がこのような範囲であれば、工程保護フィルムを用いて非常に薄いＰＶＡ系樹脂層から偏光子を作製する場合であっても、製造工程中の偏光子（実質的には、積層体）のカールを良好に防止することができる。工程保護フィルムの厚みＴ２は、上記所望のＴ１／Ｔ２が実現される限りにおいて任意の適切な厚みが採用され得る。工程保護フィルムの厚みＴ２は、例えば３０μｍ～１００μｍであり、好ましくは３５μｍ～８０μｍである。 Furthermore, in the embodiment of the present invention, the total thickness T1 of the laminate on which the process protection film is temporarily attached and the thickness T2 of the process protection film satisfy the relationship of the following formula (1):
T1 / T2 ≦ 1.0 (1).
T1 / T2 is preferably 0.95 or less, and more preferably 0.90 or less. T1 / T2 can be, for example, 0.30 or more. If T1 / T2 is in such a range, even if a polarizer is produced from a very thin PVA resin layer using a process protective film, a polarizer (substantially laminated) Body) can be satisfactorily prevented. As the thickness T2 of the process protective film, any appropriate thickness can be adopted as long as the desired T1 / T2 is realized. The thickness T2 of the process protection film is, for example, 30 μm to 100 μm, preferably 35 μm to 80 μm.
　さらに、本発明の実施形態においては、工程保護フィルムの低速剥離力は０．１２（Ｎ／２５ｍｍ）以上であり、好ましくは０．１４（Ｎ／２５ｍｍ）以上である。工程保護フィルムの低速剥離力は、例えば０．２５（Ｎ／２５ｍｍ）以下であり得る。工程保護フィルムの低速剥離力がこのような範囲であれば、工程保護フィルムを用いて非常に薄いＰＶＡ系樹脂層から偏光子を作製する場合であっても、製造工程中の偏光子（実質的には、積層体）のカールを良好に防止することができる。工程保護フィルムの高速剥離力は、上記低速剥離力の好ましくは５倍以下であり、より好ましくは４倍以下であり、さらに好ましくは３倍以下である。工程保護フィルムの高速剥離力は、上記低速剥離力の好ましくは０．８倍以上であり、より好ましくは１．０倍以上である。工程保護フィルムの高速剥離力の低速剥離力に対する比率がこのような範囲であれば、製造工程中の偏光子（実質的には、積層体）のカールを良好に防止しつつ、工程保護フィルムを剥離除去する際の偏光子の破断を良好に防止することができる。ここで、工程保護フィルムは、代表的には本体フィルムと粘着剤層とを含む。工程保護フィルムの低速剥離力および高速剥離力は、本体フィルムの構成材料および厚み、ならびに、粘着剤層の構成材料および厚みを調整することにより制御され得る。なお、剥離力は、ＪＩＳ　Ｚ　０２３７に準じて測定され得る。具体的には、剥離力は、工程保護フィルムを長さ１２０ｍｍおよび幅２５ｍｍに切り出して測定試料とし、当該測定試料を角度１８０°で剥離する際の力として定義される。本明細書において「低速剥離力」とは、上記の測定において剥離速度が３００ｍｍ／ｍｉｎの場合の剥離力をいい、「高速剥離力」とは、剥離速度が３００００ｍｍ／ｍｉｎの場合の剥離力をいう。 Furthermore, in the embodiment of the present invention, the low-speed peel force of the process protective film is 0.12 (N / 25 mm) or more, preferably 0.14 (N / 25 mm) or more. The low speed peeling force of the process protection film can be, for example, 0.25 (N / 25 mm) or less. If the low-speed peel force of the process protective film is in such a range, even if a polarizer is produced from a very thin PVA-based resin layer using the process protective film, the polarizer in the manufacturing process (substantially Therefore, curling of the laminate can be prevented satisfactorily. The high speed peel force of the process protective film is preferably 5 times or less, more preferably 4 times or less, and further preferably 3 times or less of the above low speed peel force. The high speed peeling force of the process protective film is preferably 0.8 times or more, more preferably 1.0 times or more of the above low speed peeling force. If the ratio of the high-speed peeling force to the low-speed peeling force of the process protective film is within such a range, the process protective film can be effectively prevented while curling the polarizer (substantially a laminate) during the production process. It is possible to satisfactorily prevent the polarizer from being broken when it is peeled off. Here, the process protection film typically includes a main body film and an adhesive layer. The low speed peel force and the high speed peel force of the process protective film can be controlled by adjusting the constituent material and thickness of the main body film and the constituent material and thickness of the pressure-sensitive adhesive layer. The peeling force can be measured according to JIS Z 0237. Specifically, the peeling force is defined as a force when the process protection film is cut into a length of 120 mm and a width of 25 mm to form a measurement sample, and the measurement sample is peeled at an angle of 180 °. In this specification, “low speed peel force” refers to the peel force when the peel speed is 300 mm / min in the above measurement, and “high speed peel force” refers to the peel force when the peel speed is 30000 mm / min. Say.
　以下、各工程について説明するが、上記のとおり各工程は任意の適切な順序で行われ得、記載順序に限定されるものではない。 Hereinafter, although each process will be described, each process can be performed in any appropriate order as described above, and is not limited to the description order.
Ａ－２．積層体
　積層体は、上記のとおり、ＰＶＡ系樹脂層と基材とを含む。 A-2. Laminate The laminate includes a PVA resin layer and a substrate as described above.
Ａ－２－１．ＰＶＡ系樹脂層
　ＰＶＡ系樹脂層を形成するＰＶＡ系樹脂としては、例えば、ポリビニルアルコール、エチレン－ビニルアルコール共重合体が挙げられる。ポリビニルアルコールは、ポリ酢酸ビニルをケン化することにより得られる。エチレン－ビニルアルコール共重合体は、エチレン－酢酸ビニル共重合体をケン化することにより得られる。ＰＶＡ系樹脂のケン化度は、通常８５モル％以上１００モル％未満であり、好ましくは９５．０モル％～９９．９５モル％、さらに好ましくは９９．０モル％～９９．９３モル％である。ケン化度は、ＪＩＳ　Ｋ　６７２６－１９９４に準じて求めることができる。このようなケン化度のＰＶＡ系樹脂を用いることによって、耐久性に優れた偏光子を得ることができる。ケン化度が高すぎる場合には、ゲル化してしまうおそれがある。 A-2-1. PVA-based resin layer Examples of the PVA-based resin forming the PVA-based resin layer include polyvinyl alcohol and ethylene-vinyl alcohol copolymer. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. The ethylene-vinyl alcohol copolymer can be obtained by saponifying an ethylene-vinyl acetate copolymer. The saponification degree of the PVA resin is usually 85 mol% or more and less than 100 mol%, preferably 95.0 mol% to 99.95 mol%, more preferably 99.0 mol% to 99.93 mol%. is there. The degree of saponification can be determined according to JIS K 6726-1994. By using a PVA-based resin having such a saponification degree, a polarizer having excellent durability can be obtained. If the degree of saponification is too high, there is a risk of gelation.
　ＰＶＡ系樹脂の平均重合度は、目的に応じて適切に選択され得る。平均重合度は、通常１０００～１００００であり、好ましくは１２００～４５００、さらに好ましくは１５００～４３００である。なお、平均重合度は、ＪＩＳ　Ｋ　６７２６－１９９４に準じて求めることができる。 The average degree of polymerization of the PVA resin can be appropriately selected according to the purpose. The average degree of polymerization is usually 1000 to 10,000, preferably 1200 to 4500, and more preferably 1500 to 4300. The average degree of polymerization can be determined according to JIS K 6726-1994.
　ＰＶＡ系樹脂層は、ＰＶＡ系樹脂フィルムと基材とを積層して形成されてもよく、上記ＰＶＡ系樹脂を含む塗布液を基材に塗布および乾燥して形成されてもよい。 The PVA resin layer may be formed by laminating a PVA resin film and a base material, or may be formed by applying and drying a coating liquid containing the PVA resin on the base material.
Ａ－２－２．基材
　積層体に工程保護フィルムが仮着される時点において、基材は、偏光子作製のみに用いられる基材（偏光子作製用基材）であってもよく、光学機能フィルムであってもよい。基材が偏光子作製用基材である場合、当該基材は、代表的には、偏光子作製後に剥離除去される。基材が光学機能フィルムである場合、当該基材は、偏光子作製後も剥離されずにそのまま用いられ得る。さらに、基材が光学機能フィルムである場合、（ｉ）光学機能フィルム上にＰＶＡ系樹脂層を形成して積層体を作製し、当該積層体の光学機能フィルム側に工程保護フィルムを仮着してもよく；（ｉｉ）ＰＶＡ系樹脂層と偏光子作製用基材とを含む積層体のＰＶＡ系樹脂層側に光学機能フィルムを貼り合わせて偏光子作製用基材／ＰＶＡ系樹脂層／光学機能フィルムの積層体を作製し、当該積層体から偏光子作製用基材を剥離除去してＰＶＡ系樹脂層／光学機能フィルムの積層体を作製し、当該積層体の光学機能フィルム側に工程保護フィルムを仮着してもよい。 A-2-2. Substrate At the time when the process protective film is temporarily attached to the laminate, the substrate may be a substrate used only for the production of a polarizer (a substrate for producing a polarizer) or an optical functional film. Good. When the substrate is a substrate for preparing a polarizer, the substrate is typically peeled off after the polarizer is manufactured. When a base material is an optical function film, the said base material can be used as it is, without peeling even after polarizer production. Furthermore, when the substrate is an optical functional film, (i) a PVA-based resin layer is formed on the optical functional film to produce a laminate, and a process protective film is temporarily attached to the optical functional film side of the laminate. (Ii) The optical functional film is bonded to the PVA-based resin layer side of the laminate including the PVA-based resin layer and the polarizer-forming substrate, and the polarizer-producing substrate / PVA-based resin layer / optical A laminated body of functional films is produced, and a substrate for preparing a polarizer is peeled and removed from the laminated body to produce a laminated body of PVA-based resin layer / optical functional film, and process protection is provided on the optical functional film side of the laminated body. A film may be temporarily attached.
　基材が偏光子作製用基材である場合、基材の構成材料としては、任意の適切な熱可塑性樹脂が採用され得る。熱可塑性樹脂としては、例えば、ポリエチレンテレフタレート系樹脂等のエステル系樹脂、ノルボルネン系樹脂等のシクロオレフィン系樹脂、ポリプロピレン等のオレフィン系樹脂、ポリアミド系樹脂、ポリカーボネート系樹脂、これらの共重合体樹脂等が挙げられる。好ましくは、ノルボルネン系樹脂、非晶質のポリエチレンテレフタレート系樹脂である。好ましくは、非晶質の（結晶化していない）ポリエチレンテレフタレート系樹脂であり、より好ましくは、非晶性の（結晶化しにくい）ポリエチレンテレフタレート系樹脂である。 When the base material is a base material for producing a polarizer, any appropriate thermoplastic resin can be adopted as a constituent material of the base material. Examples of the thermoplastic resin 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. Is mentioned. Preferred are norbornene resins and amorphous polyethylene terephthalate resins. An amorphous (non-crystallized) polyethylene terephthalate resin is preferable, and an amorphous (hard to crystallize) polyethylene terephthalate resin is more preferable.
　基材が光学機能フィルムである場合、光学機能フィルムの具体例としては、位相差フィルム、偏光子保護フィルム、輝度向上フィルムが挙げられる。 When the substrate is an optical functional film, specific examples of the optical functional film include a retardation film, a polarizer protective film, and a brightness enhancement film.
Ａ－３．延伸工程
　延伸工程において、積層体は、代表的には３倍～７倍に一軸延伸される。延伸方向は、積層体の長手方向（ＭＤ方向）であってもよく、積層体の幅方向（ＴＤ方向）であってもよい。延伸方法は、乾式延伸であってもよく、湿式延伸であってもよく、これらを組み合せてもよい。また、架橋工程、膨潤工程、染色工程等を行う際に積層体を延伸してもよい。なお、延伸方向は、得られる偏光子の吸収軸方向に対応し得る。 A-3. Stretching step In the stretching step, the laminate is typically uniaxially stretched 3 to 7 times. The stretching direction may be the longitudinal direction (MD direction) of the laminate, or the width direction (TD direction) of the laminate. The stretching method may be dry stretching, wet stretching, or a combination thereof. Moreover, you may extend | stretch a laminated body, when performing a bridge | crosslinking process, a swelling process, a dyeing process, etc. The stretching direction can correspond to the absorption axis direction of the obtained polarizer.
　代表的には、ＰＶＡ系樹脂層は、工程保護フィルムを積層体に仮着する前に延伸されている。したがって、上記Ａ－１項に記載のＰＶＡ系樹脂層の厚みは、代表的には延伸後の厚みであり、最終的に得られる偏光子の厚みと同等であり得る。この場合、（ｉ）光学機能フィルム上にＰＶＡ系樹脂層を形成して積層体を作製し、当該積層体を延伸し、延伸後の積層体の光学機能フィルム側に工程保護フィルムを仮着してもよく；（ｉｉ）ＰＶＡ系樹脂層と偏光子作製用基材とを含む積層体を延伸し、延伸後の積層体のＰＶＡ系樹脂層側に光学機能フィルムを貼り合わせて偏光子作製用基材／ＰＶＡ系樹脂層／光学機能フィルムの積層体を作製し、当該積層体から偏光子作製用基材を剥離除去してＰＶＡ系樹脂層／光学機能フィルムの積層体を作製し、当該積層体の光学機能フィルム側に工程保護フィルムを仮着してもよい。さらに、光学機能フィルム前駆体上にＰＶＡ系樹脂層を形成して積層体を作製し、当該積層体を延伸することにより、ＰＶＡ系樹脂層を延伸するとともに光学機能フィルム前駆体から光学機能フィルムを形成し、結果として、ＰＶＡ系樹脂層／光学機能フィルムの積層体を作製してもよい。このような構成は、光学機能フィルムが位相差フィルムである場合に好適である。 Typically, the PVA resin layer is stretched before temporarily attaching the process protection film to the laminate. Therefore, the thickness of the PVA-based resin layer described in the above section A-1 is typically a thickness after stretching, and may be equal to the thickness of the finally obtained polarizer. In this case, (i) a PVA-based resin layer is formed on the optical functional film to produce a laminate, the laminate is stretched, and a process protective film is temporarily attached to the optical functional film side of the stretched laminate. (Ii) A laminate including a PVA resin layer and a polarizer preparation substrate is stretched, and an optical functional film is bonded to the PVA resin layer side of the stretched laminate to produce a polarizer. A laminate of the base material / PVA resin layer / optical functional film is prepared, and the polarizer preparation base material is peeled off from the laminate to prepare a laminate of PVA resin layer / optical functional film. A process protective film may be temporarily attached to the optical functional film side of the body. Furthermore, a PVA-based resin layer is formed on the optical functional film precursor to produce a laminate, and the laminate is stretched to stretch the PVA-based resin layer and to convert the optical functional film from the optical functional film precursor. As a result, a laminate of PVA resin layer / optical functional film may be produced. Such a configuration is suitable when the optical functional film is a retardation film.
Ａ－４．膨潤工程
　膨潤工程は、通常、染色工程の前に行われる。膨潤工程は、例えば、積層体（実質的には、ＰＶＡ系樹脂層）を膨潤浴に浸漬することにより行われる。膨潤浴としては、通常、蒸留水、純水等の水が用いられる。膨潤浴は、水以外の任意の適切な他の成分を含んでいてもよい。他の成分としては、アルコール等の溶媒、界面活性剤等の添加剤、ヨウ化物等が挙げられる。ヨウ化物としては、例えば、ヨウ化カリウム、ヨウ化リチウム、ヨウ化ナトリウム、ヨウ化亜鉛、ヨウ化アルミニウム、ヨウ化鉛、ヨウ化銅、ヨウ化バリウム、ヨウ化カルシウム、ヨウ化錫、ヨウ化チタン等が挙げられる。好ましくは、ヨウ化カリウムが用いられる。膨潤浴の温度は、例えば、２０℃～４５℃である。また、浸漬時間は、例えば、１０秒～３００秒である。 A-4. Swelling process The swelling process is usually performed before the dyeing process. A swelling process is performed by immersing a laminated body (substantially PVA-type resin layer) in a swelling bath, for example. As the swelling bath, water such as distilled water or pure water is usually used. The swelling bath may contain any appropriate other component other than water. Examples of other components include alcohols and other solvents, surfactants and other additives, and iodides. Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, and titanium iodide. Etc. Preferably, potassium iodide is used. The temperature of the swelling bath is, for example, 20 ° C. to 45 ° C. The immersion time is, for example, 10 seconds to 300 seconds.
Ａ－５．工程保護フィルムの仮着工程
　工程保護フィルムの仮着工程は、上記Ａ－１項に記載のとおり、染色工程の前に行われる。工程保護フィルムの厚みおよび剥離力は、上記Ａ－１項で説明したとおりである。また、工程保護フィルムの厚みは、本体フィルムの厚みである。工程保護フィルム（本体フィルム）の構成材料としては、ヤング率の高い材料が好ましい。いわゆる腰の強いフィルムを実現することができるからである。工程保護フィルムのヤング率は、好ましくは１０００ＭＰａ以上である。工程保護フィルムの構成材料の具体例としては、ポリエチレンテレフタレート（ＰＥＴ）、ポリエチエレンナフタレート（ＰＥＮ）、ポリプロピレン（ＰＰ）、シクロオレフィン系樹脂（ＣＯＰ）が挙げられる。また、工程保護フィルムの粘着剤としては、帯電防止剤または界面活性剤のいずれか、あるいはそれらの両方を含まないことが好ましい。このような粘着剤であれば、溶出による染色浴および／または架橋浴の汚染を防止することができ、品質にばらつきのない偏光子を得ることができる。 A-5. Process Protection Film Temporary Attachment Process The process protection film temporary attachment process is performed before the dyeing process as described in the above section A-1. The thickness and peeling force of the process protective film are as described in the above section A-1. Moreover, the thickness of a process protection film is the thickness of a main body film. As a constituent material of the process protection film (main film), a material having a high Young's modulus is preferable. This is because a so-called strong film can be realized. The Young's modulus of the process protective film is preferably 1000 MPa or more. Specific examples of the constituent material of the process protective film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polypropylene (PP), and cycloolefin resin (COP). In addition, it is preferable that the pressure-sensitive adhesive for the process protective film does not contain either an antistatic agent or a surfactant, or both. With such an adhesive, contamination of the dyeing bath and / or crosslinking bath due to elution can be prevented, and a polarizer having no variation in quality can be obtained.
Ａ－６．染色工程
　染色工程は、上記Ａ－１項に記載のとおり、工程保護フィルムの仮着工程の後に行われる。染色工程は、ＰＶＡ系樹脂層を二色性物質で染色する工程である。好ましくは二色性物質を吸着させることにより行う。当該吸着方法としては、例えば、二色性物質を含む染色液に積層体（実質的には、ＰＶＡ系樹脂層）を浸漬させる方法、積層体（実質的には、ＰＶＡ系樹脂層）に当該染色液を塗工する方法、当該染色液を積層体（実質的には、ＰＶＡ系樹脂層）に噴霧する方法等が挙げられる。好ましくは、染色液に積層体（実質的には、ＰＶＡ系樹脂層）を浸漬させる方法である。二色性物質が良好に吸着し得るからである。 A-6. Dyeing process The dyeing process is performed after the temporary attachment process of the process protective film as described in the above section A-1. The dyeing step is a step of dyeing the PVA resin layer with a dichroic substance. Preferably, it is carried out by adsorbing a dichroic substance. As the adsorption method, for example, a method of immersing a laminate (substantially, a PVA resin layer) in a staining solution containing a dichroic substance, or a method of immersing the laminate (substantially, a PVA resin layer) Examples thereof include a method of applying a staining solution, a method of spraying the staining solution onto a laminate (substantially, a PVA resin layer), and the like. Preferably, it is a method of immersing the laminate (substantially, the PVA resin layer) in the dyeing solution. It is because a dichroic substance can adsorb | suck favorably.
　上記二色性物質としては、例えば、ヨウ素、二色性染料が挙げられる。好ましくは、ヨウ素である。二色性物質としてヨウ素を用いる場合、染色液としては、ヨウ素水溶液が好ましく用いられる。ヨウ素水溶液のヨウ素の含有量は、水１００重量部に対して、好ましくは０．０４重量部～５．０重量部である。ヨウ素の水に対する溶解度を高めるため、ヨウ素水溶液にヨウ化物を配合することが好ましい。ヨウ化物としては、ヨウ化カリウムが好ましく用いられる。ヨウ化物の含有量は、水１００重量部に対して、好ましくは０．３重量部～１５重量部である。 Examples of the dichroic substance include iodine and dichroic dyes. Preferably, it is iodine. When iodine is used as the dichroic substance, an aqueous iodine solution is preferably used as the staining solution. The iodine content of the aqueous iodine solution is preferably 0.04 to 5.0 parts by weight with respect to 100 parts by weight of water. In order to increase the solubility of iodine in water, it is preferable to add an iodide to the aqueous iodine solution. As the iodide, potassium iodide is preferably used. The iodide content is preferably 0.3 to 15 parts by weight with respect to 100 parts by weight of water.
　染色液の染色時の液温は、任意の適切な値に設定することができ、例えば、２０℃～５０℃である。染色液に積層体（実質的には、ＰＶＡ系樹脂層）を浸漬させる場合、浸漬時間は、例えば、５秒～５分である。 The liquid temperature during staining of the staining liquid can be set to any appropriate value, for example, 20 ° C. to 50 ° C. When the laminate (substantially, the PVA resin layer) is immersed in the staining solution, the immersion time is, for example, 5 seconds to 5 minutes.
Ａ－７．架橋工程
　架橋工程においては、通常、架橋剤としてホウ素化合物が用いられる。ホウ素化合物としては、例えば、ホウ酸、ホウ砂等が挙げられる。好ましくは、ホウ酸である。架橋工程においては、ホウ素化合物は、通常、水溶液の形態で用いられる。 A-7. Crosslinking step In the crosslinking step, a boron compound is usually used as a crosslinking agent. Examples of the boron compound include boric acid and borax. Preferably, it is a boric acid. In the crosslinking step, the boron compound is usually used in the form of an aqueous solution.
　ホウ酸水溶液を用いる場合、ホウ酸水溶液のホウ酸濃度は、例えば、１重量％～１５重量％であり、好ましくは１重量％～１０重量％である。ホウ酸水溶液には、ヨウ化カリウム等のヨウ化物、硫酸亜鉛、塩化亜鉛等の亜鉛化合物をさらに含有させてもよい。 When a boric acid aqueous solution is used, the boric acid concentration of the boric acid aqueous solution is, for example, 1% by weight to 15% by weight, and preferably 1% by weight to 10% by weight. The boric acid aqueous solution may further contain an iodide such as potassium iodide, or a zinc compound such as zinc sulfate or zinc chloride.
　架橋工程は、任意の適切な方法により行うことができる。例えば、ホウ素化合物を含む水溶液に積層体（実質的には、ＰＶＡ系樹脂層）を浸漬する方法、ホウ素化合物を含む水溶液を積層体（実質的には、ＰＶＡ系樹脂層）に塗布する方法、または、ホウ素化合物を含む水溶液を積層体（実質的には、ＰＶＡ系樹脂層）に噴霧する方法が挙げられる。ホウ素化合物を含む水溶液に浸漬することが好ましい。 The crosslinking step can be performed by any appropriate method. For example, a method of immersing a laminate (substantially, a PVA resin layer) in an aqueous solution containing a boron compound, a method of applying an aqueous solution containing a boron compound to a laminate (substantially, a PVA resin layer), Or the method of spraying the aqueous solution containing a boron compound on a laminated body (substantially PVA-type resin layer) is mentioned. It is preferable to immerse in an aqueous solution containing a boron compound.
　架橋に用いる溶液の温度は、例えば、２５℃以上であり、好ましくは３０℃～８５℃、さらに好ましくは４０℃～７０℃である。浸漬時間は、例えば、５秒～８００秒であり、好ましくは８秒～５００秒である。 The temperature of the solution used for crosslinking is, for example, 25 ° C. or higher, preferably 30 ° C. to 85 ° C., more preferably 40 ° C. to 70 ° C. The immersion time is, for example, 5 seconds to 800 seconds, and preferably 8 seconds to 500 seconds.
　本発明の実施形態によれば、架橋工程における工程保護フィルムの剥がれを良好に防止することができる。 According to the embodiment of the present invention, it is possible to satisfactorily prevent the process protective film from peeling off in the crosslinking process.
Ａ－８．洗浄工程
　洗浄工程は、代表的には、架橋工程以降に行われ得る。洗浄工程は、代表的には、積層体を洗浄液に浸漬させることにより行われる。洗浄液の代表例としては、純水が挙げられる。純水にヨウ化カリウムを添加してもよい。 A-8. Washing step The washing step can typically be performed after the crosslinking step. The cleaning step is typically performed by immersing the laminate in a cleaning solution. A typical example of the cleaning liquid is pure water. Potassium iodide may be added to pure water.
　洗浄液の温度は、例えば５℃～５０℃である。浸漬時間は、例えば１秒～３００秒である。 The temperature of the cleaning liquid is, for example, 5 ° C to 50 ° C. The immersion time is, for example, 1 second to 300 seconds.
Ａ－９．乾燥工程
　乾燥工程は、任意の適切な方法により行うことができる。乾燥方法としては、例えば、自然乾燥、送風乾燥、減圧乾燥、加熱乾燥等が挙げられる。加熱乾燥が好ましく用いられる。加熱乾燥を行う場合、加熱温度は、例えば、３０℃～１００℃である。また、乾燥時間は、例えば、２０秒～１０分間である。なお、乾燥は多段階（例えば、二段階）で行ってもよい。 A-9. Drying step The drying step can be performed by any appropriate method. Examples of the drying method include natural drying, air drying, reduced pressure drying, and heat drying. Heat drying is preferably used. In the case of performing heat drying, the heating temperature is, for example, 30 ° C. to 100 ° C. The drying time is, for example, 20 seconds to 10 minutes. The drying may be performed in multiple stages (for example, two stages).
　本発明の実施形態によれば、乾燥後の工程保護フィルムの剥がれおよび偏光子（実質的には、積層体）のカールを良好に防止することができる。 According to the embodiment of the present invention, it is possible to satisfactorily prevent peeling of the process protective film after drying and curling of the polarizer (substantially a laminate).
　以上のようにして、基材上に偏光子が作製され得る。この後、工程保護フィルムが除去されるまでの間に、粘着剤の塗布工程などが行われてもよい。 Thus, a polarizer can be produced on the substrate. Thereafter, an adhesive application step or the like may be performed before the process protective film is removed.
Ａ－１０．工程保護フィルムの除去工程
　偏光子作製後、工程保護フィルムは除去（代表的には、剥離）される。代表的には、工程保護フィルムの剥離後、剥離面に表面保護フィルムが貼り合わせられる。すなわち、偏光子作製後、工程保護フィルムは表面保護フィルムに貼り換えられる。積層体の基材が剥離除去される場合には、積層体の基材（および工程保護フィルム）と反対側に光学機能フィルムが貼り合わせされ、次いで、工程保護フィルムおよび基材が積層体から剥離除去され、当該剥離面に表面保護フィルムが貼り合わせられる。 A-10. Step Protection Film Removal Step After the production of the polarizer, the step protection film is removed (typically peeled off). Typically, after the process protective film is peeled off, the surface protective film is bonded to the peeled surface. That is, after the polarizer is produced, the process protection film is replaced with a surface protection film. When the base material of the laminate is peeled and removed, the optical functional film is bonded to the opposite side of the base material (and the process protection film) of the laminate, and then the process protection film and the base material are peeled from the laminate. The surface protective film is bonded to the release surface.
Ｂ．偏光子
　本発明の製造方法により得られる偏光子のヨウ素含有量は、十分な偏光性能と最適な透過率とを付与する観点から、偏光子の厚みに応じて適切に設定され得る。例えば、偏光子の厚みが３μｍを超えて５μｍ以下である場合には、ヨウ素含有量は好ましくは５．０重量％～１３．０重量％であり；偏光子の厚みが３μｍ以下である場合には、ヨウ素含有量は好ましくは１０．０重量％～２５．０重量％である。本明細書において「ヨウ素含有量」とは、偏光子（ＰＶＡ系樹脂層）中に含まれるすべてのヨウ素の量を意味する。より具体的には、偏光子中においてヨウ素はヨウ素イオン（Ｉ－）、ヨウ素分子（Ｉ２）、ポリヨウ素イオン（Ｉ３ －、Ｉ５ －）等の形態で存在するところ、本明細書におけるヨウ素含有量は、これらの形態をすべて包含したヨウ素の量を意味する。ヨウ素含有量は、例えば、蛍光Ｘ線分析の検量線法により算出することができる。 B. Polarizer The iodine content of the polarizer obtained by the production method of the present invention can be appropriately set according to the thickness of the polarizer from the viewpoint of providing sufficient polarization performance and optimum transmittance. For example, when the thickness of the polarizer is more than 3 μm and 5 μm or less, the iodine content is preferably 5.0 wt% to 13.0 wt%; when the thickness of the polarizer is 3 μm or less The iodine content is preferably 10.0% to 25.0% by weight. In this specification, the “iodine content” means the amount of all iodine contained in the polarizer (PVA resin layer). More specifically, iodine exists in the form of iodine ions (I − ), iodine molecules (I 2 ), polyiodine ions (I 3 − , I 5 − ), etc. in the polarizer. Iodine content means the amount of iodine encompassing all these forms. The iodine content can be calculated, for example, by a calibration curve method of fluorescent X-ray analysis.
Ｃ．偏光板
　本発明の製造方法により得られる偏光子は、代表的には、その片側または両側に保護フィルムが積層された状態で（すなわち、偏光板として）使用される。実用的には、偏光板は、最外層として粘着剤層を有する。粘着剤層は、代表的には画像表示装置側の最外層となる。粘着剤層には、セパレーターが剥離可能に仮着され、実際の使用まで粘着剤層を保護するとともに、ロール形成を可能としている。 C. Polarizer The polarizer obtained by the production method of the present invention is typically used in a state where a protective film is laminated on one side or both sides thereof (that is, as a polarizer). 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.
　保護フィルムとしては、任意の適切な樹脂フィルムが用いられる。樹脂フィルムの形成材料としては、例えば、（メタ）アクリル系樹脂、ジアセチルセルロース、トリアセチルセルロース等のセルロース系樹脂、ノルボルネン系樹脂等のシクロオレフィン系樹脂、ポリプロピレン等のオレフィン系樹脂、ポリエチレンテレフタレート系樹脂等のエステル系樹脂、ポリアミド系樹脂、ポリカーボネート系樹脂、これらの共重合体樹脂等が挙げられる。なお、「（メタ）アクリル系樹脂」とは、アクリル系樹脂および／またはメタクリル系樹脂をいう。 Any appropriate resin film is used as the protective film. Examples of the resin film forming material include (meth) acrylic resins, cellulose resins such as diacetyl cellulose and triacetyl cellulose, cycloolefin resins such as norbornene resins, olefin resins such as polypropylene, and polyethylene terephthalate resins. And ester resins such as polyamide resins, polycarbonate resins, and copolymer resins thereof. The “(meth) acrylic resin” refers to an acrylic resin and / or a methacrylic resin.
　以下、実施例によって本発明を具体的に説明するが、本発明はこれら実施例によって限定されるものではない。なお、各特性の測定方法は以下の通りである。 Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. In addition, the measuring method of each characteristic is as follows.
（１）剥離力
　ＪＩＳ　Ｚ　０２３７に準じて測定した。具体的には以下のとおりである：実施例および比較例で用いた工程保護フィルムを長さ１２０ｍｍおよび幅２５ｍｍに切り出して測定試料とした。当該測定試料を、実施例および比較例で得られた基材／偏光子の積層体の基材側に貼り付け、引張試験機（テスター産業社製、製品名「ＴＥ－７０２高速剥離試験機」）を用いて剥離角度１８０°で引き剥がした際の剥離力を測定した。低速剥離力は、剥離速度が３００ｍｍ／ｍｉｎの場合の剥離力を測定した。高速剥離力は、剥離速度が３００００ｍｍ／ｍｉｎの場合の剥離力を測定した。
（２）工程保護フィルムの剥がれ
　実施例および比較例の製造方法において、工程保護フィルムの剥がれの有無を目視により確認し、下記の基準で評価した。なお、剥がれの有無は、架橋工程後および乾燥工程後の２つの時点で確認した。
　　　　○：剥がれは認められない
　　　　×：剥がれが認められる
（３）カール
　実施例および比較例の製造方法において、乾燥工程後の（すなわち、乾燥オーブンから出てきた）工程保護フィルム／基材／偏光子の積層体の幅方向（ＴＤ）の反り量を測定し、以下の基準で評価した。
　　　　○：反り量が５０ｍｍ未満である
　　　　×：反り量が５０ｍｍ以上である
（４）破断
　実施例および比較例の製造方法において、洗浄工程後の搬送速度を２０ｍ／ｍｉｎ以上に設定した。乾燥工程後に工程保護フィルムを剥離した際の積層体（偏光板）の破断の有無を目視により確認し、以下の基準で評価した。
　　　　○：破断は認められない
　　　　×：破断が認められる (1) Peeling force Measured according to JIS Z 0237. Specifically, the process protective film used in the examples and comparative examples was cut into a length of 120 mm and a width of 25 mm to obtain a measurement sample. The measurement sample was affixed to the substrate side of the laminate of the substrate / polarizer obtained in the examples and comparative examples, and a tensile tester (product name “TE-702 high-speed peel tester” manufactured by Tester Sangyo Co., Ltd.). ) Was used to measure the peel force when peeled at a peel angle of 180 °. For the low speed peel force, the peel force was measured when the peel speed was 300 mm / min. The high-speed peeling force measured the peeling force when the peeling speed was 30000 mm / min.
(2) Peeling of process protective film In the production methods of Examples and Comparative Examples, the presence or absence of peeling of the process protective film was confirmed by visual observation and evaluated according to the following criteria. The presence or absence of peeling was confirmed at two points after the crosslinking step and after the drying step.
○: No peeling is observed ×: Peeling is recognized (3) Curl In the production methods of Examples and Comparative Examples, the process protective film / substrate / polarizer after the drying process (that is, from the drying oven) The amount of warpage in the width direction (TD) of the laminate was measured and evaluated according to the following criteria.
○: Warpage amount is less than 50 mm ×: Warpage amount is 50 mm or more (4) Breaking In the production methods of Examples and Comparative Examples, the conveyance speed after the cleaning step was set to 20 m / min or more. The presence or absence of breakage of the laminate (polarizing plate) when the process protective film was peeled off after the drying process was visually confirmed and evaluated according to the following criteria.
○: No breakage is observed ×: Breakage is observed
［製造例１］
　常法を用いて、アクリル酸２－エチルヘキシル（５５重量部）、酢酸ビニル（４５重量部）およびアクリル酸（３重量部）を共重合してアクリル系ポリマーを得た。当該アクリル系ポリマーをトルエンで希釈し、２０重量％トルエン溶液を調製した。当該トルエン溶液に、アクリル系ポリマー１００重量部に対してエポキシ系架橋剤（テトラッドＣ、三菱瓦斯化学製）を２重量部配合し、粘着剤組成物を得た。得られた粘着剤組成物を、３８μｍのＰＥＴフィルム（三菱化学ポリエステル製，Ｔ１００）に乾燥後の厚みが５μｍとなるように塗布し、１３０℃で１分間乾燥して粘着剤層を形成した。このようにして、本体フィルム（ＰＥＴフィルム）／粘着剤層の構成を有する工程保護フィルムＡを作製した。工程保護フィルムＡの低速剥離力は０．１４（Ｎ／２５ｍｍ）であり、高速剥離力は０．１７（Ｎ／２５ｍｍ）であった。 [Production Example 1]
Using an ordinary method, 2-ethylhexyl acrylate (55 parts by weight), vinyl acetate (45 parts by weight) and acrylic acid (3 parts by weight) were copolymerized to obtain an acrylic polymer. The acrylic polymer was diluted with toluene to prepare a 20 wt% toluene solution. In the toluene solution, 2 parts by weight of an epoxy crosslinking agent (Tetrad C, manufactured by Mitsubishi Gas Chemical) was blended with 100 parts by weight of the acrylic polymer to obtain an adhesive composition. The obtained pressure-sensitive adhesive composition was applied to a 38 μm PET film (manufactured by Mitsubishi Chemical Polyester, T100) so that the thickness after drying was 5 μm, and dried at 130 ° C. for 1 minute to form a pressure-sensitive adhesive layer. Thus, the process protection film A which has the structure of a main body film (PET film) / adhesive layer was produced. The low speed peel force of the process protective film A was 0.14 (N / 25 mm), and the high speed peel force was 0.17 (N / 25 mm).
［製造例２］
　本体フィルム（ＰＥＴフィルム）として三菱化学ポリエステル製「Ｔ１００－７５」（厚み７５μｍ）を用いたこと以外は製造例１と同様にして工程保護フィルムＢを作製した。工程保護フィルムＢの低速剥離力は０．１２（Ｎ／２５ｍｍ）であり、高速剥離力は０．４５（Ｎ／２５ｍｍ）であった。 [Production Example 2]
A process protective film B was produced in the same manner as in Production Example 1 except that Mitsubishi Chemical Polyester “T100-75” (thickness 75 μm) was used as the main body film (PET film). The low speed peel force of the process protective film B was 0.12 (N / 25 mm), and the high speed peel force was 0.45 (N / 25 mm).
［製造例３］
　市販の粘着剤層付ＰＥＴフィルム（藤森工業（株）製、製品名「ＡＳ３－３０４」、本体フィルムの厚み３８μｍ、粘着剤層の厚み２０μｍ）をそのまま用い、工程保護フィルムＣとした。工程保護フィルムＣの低速剥離力は０．１１（Ｎ／２５ｍｍ）であり、高速剥離力は２．２０（Ｎ／２５ｍｍ）であった。 [Production Example 3]
A commercially available PET film with a pressure-sensitive adhesive layer (manufactured by Fujimori Kogyo Co., Ltd., product name “AS3-304”, main body film thickness 38 μm, pressure-sensitive adhesive layer thickness 20 μm) was used as it was as a process protective film C. The low speed peel force of the process protective film C was 0.11 (N / 25 mm), and the high speed peel force was 2.20 (N / 25 mm).
［製造例４］
　攪拌羽根、温度計、窒素ガス導入管、冷却器を備えた四つ口フラスコに、２－エチルヘキシルアクリレート２００重量部、２－ヒドロキシエチルアクリレート８重量部、重合開始剤として２，２´－アゾビスイソブチロニトリル０．４重量部、溶剤として酢酸エチル３１２重量部を仕込み、緩やかに撹拌しながら窒素ガスを導入し、フラスコ内の液温を６５℃付近に保って６時間重合反応を行い、アクリル系ポリマー溶液（４０重量％）を調製した。得られたアクリル系ポリマー溶液（４０重量％）を酢酸エチルで２０重量％に希釈し、この溶液中の固形分１００重量部に対して、芳香族環を有する界面活性剤としてポリオキシエチレンノニルフェニルエーテル硫酸アンモニウム（商品名「ハイテノールＮ－０８」、第一工業製薬社製）０．１重量部、架橋剤としてヘキサメチレンジイソシアネートのイソシアヌレート体（商品名「コロネートＨＸ」、日本ポリウレタン工業社製）５重量部、架橋触媒としてジラウリン酸ジブチルスズ（商品名「ＯＬ－１」、東京ファインケミカル社製）０．０３重量部を加えた。さらに、架橋遅延剤としてアセチルアセトンを全溶剤量に対して３重量部、および、界面活性剤として２，４，７，９－テトラメチル－５－デシン４，７－ジオールのポリエーテル化物（商品名「サーフィノール４８５」、エアープロダクツ社製）１．０重量部を加えた。そして、混合撹拌を行い、アクリル系粘着剤組成物を調製した。この粘着剤組成物を用いて厚み１０μｍの粘着剤層を形成したこと以外は製造例１と同様にして工程保護フィルムＤを作製した。工程保護フィルムＤの低速剥離力は０．０９（Ｎ／２５ｍｍ）であり、高速剥離力は１．２３（Ｎ／２５ｍｍ）であった。 [Production Example 4]
In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, and condenser, 200 parts by weight of 2-ethylhexyl acrylate, 8 parts by weight of 2-hydroxyethyl acrylate, and 2,2′-azobis as a polymerization initiator Charge 0.4 parts by weight of isobutyronitrile and 312 parts by weight of ethyl acetate as a solvent, introduce nitrogen gas while gently stirring, and perform a polymerization reaction for 6 hours while maintaining the liquid temperature in the flask at around 65 ° C. An acrylic polymer solution (40% by weight) was prepared. The obtained acrylic polymer solution (40% by weight) was diluted to 20% by weight with ethyl acetate, and polyoxyethylene nonylphenyl as a surfactant having an aromatic ring with respect to 100 parts by weight of the solid content in this solution. Ammonium ether sulfate (trade name “Hitenol N-08”, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 0.1 parts by weight, hexamethylene diisocyanate isocyanurate as a crosslinking agent (trade name “Coronate HX”, manufactured by Nippon Polyurethane Industry Co., Ltd.) 5 parts by weight and 0.03 part by weight of dibutyltin dilaurate (trade name “OL-1”, manufactured by Tokyo Fine Chemical Co., Ltd.) were added as a crosslinking catalyst. Further, 3 parts by weight of acetylacetone as a crosslinking retarder with respect to the total amount of solvent, and 2,4,7,9-tetramethyl-5-decyne 4,7-diol as a surfactant (trade name) 1.0 part by weight of “Surfinol 485” (manufactured by Air Products) was added. And mixing stirring was performed and the acrylic adhesive composition was prepared. A process protective film D was produced in the same manner as in Production Example 1 except that a pressure-sensitive adhesive layer having a thickness of 10 μm was formed using this pressure-sensitive adhesive composition. The low speed peel force of the process protective film D was 0.09 (N / 25 mm), and the high speed peel force was 1.23 (N / 25 mm).
［製造例５］
　市販の自己粘着型ポリエチレンフィルム（東レフィルム加工社製、製品名「トレテック＃３０　７３３２」、本体フィルムの厚み３０μｍ）をそのまま用い、工程保護フィルムＥとした。工程保護フィルムＥの低速剥離力は０．０８（Ｎ／２５ｍｍ）であり、高速剥離力は０．０７（Ｎ／２５ｍｍ）であった。 [Production Example 5]
A commercially available self-adhesive polyethylene film (manufactured by Toray Film Processing Co., Ltd., product name “Tretec # 30 7332”, thickness of main body film 30 μm) was used as it was and was designated as process protective film E. The low speed peel force of the process protective film E was 0.08 (N / 25 mm), and the high speed peel force was 0.07 (N / 25 mm).
［実施例１］
　熱可塑性樹脂基材として、吸水率０．７５％、Ｔｇ７５℃の非晶質のイソフタル酸共重合ポリエチレンテレフタレート（ＩＰＡ共重合ＰＥＴ）フィルム（厚み：１００μｍ）を用いた。基材の片面に、コロナ処理を施し、このコロナ処理面に、ポリビニルアルコール（重合度４２００、ケン化度９９．２モル％）およびアセトアセチル変性ＰＶＡ（重合度１２００、アセトアセチル変性度４．６％、ケン化度９９．０モル％以上、日本合成化学工業社製、商品名「ゴーセファイマーＺ２００」）を９：１の比で含む水溶液を２５℃で塗布および乾燥して、厚み１１μｍのＰＶＡ系樹脂層を形成し、積層体を作製した。
　得られた積層体を、テンター延伸機を用いて、１４０℃で積層体の長手方向と直交する方向に４．５倍空中延伸した（延伸処理）。当該延伸により、ＰＶＡ系樹脂層の厚みは２．５μｍとなった。
　この積層体の基材側に、製造例１の工程保護フィルムＡを貼り合わせ、工程保護フィルムＡ／基材／ＰＶＡ系樹脂層の構成を有する積層体を作製した。
　得られた積層体を液温２５℃の染色浴（ヨウ素濃度１．４重量％およびヨウ化カリウム濃度９．８重量％の水溶液）に１２秒間浸漬させ、染色した（染色処理）。
　次いで、積層体を液温２５℃の洗浄浴（純水）に６秒間浸漬させた（第１洗浄処理）。
　次いで、液温６０℃の架橋浴（ホウ素濃度１重量％およびヨウ化カリウム濃度１重量％の水溶液）に１６秒間浸漬させた（架橋処理）。
　次いで、積層体を液温２５℃の洗浄浴（ヨウ化カリウム濃度１重量％の水溶液）に３秒間浸漬させた（第２洗浄処理）。
　次いで、積層体を６０℃のオーブンで２１秒間乾燥させ（第１乾燥処理）、さらに、５０℃のオーブンで６０秒間乾燥させた（第２乾燥処理）。
　最後に、工程保護フィルムＡを剥離除去して、基材／偏光子（厚み２．５μｍ）の構成を有する積層体を得た。
　得られた積層体を上記（２）～（４）の評価に供した。結果を表１に示す。 [Example 1]
As a thermoplastic resin substrate, an amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 μm) having a water absorption of 0.75% and Tg of 75 ° C. was used. One side of the substrate was subjected to corona treatment, and polyvinyl alcohol (degree of polymerization 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (degree of polymerization 1200, degree of acetoacetyl modification 4.6) were applied to this corona-treated surface. %, A saponification degree of 99.0 mol% or more, an aqueous solution containing 9: 1 ratio of Nippon Gosei Kagaku Kogyo Co., Ltd., trade name “Gosefimer Z200”) was applied and dried at 25 ° C. to a thickness of 11 μm. A PVA resin layer was formed to prepare a laminate.
The obtained laminate was stretched in the air 4.5 times in a direction perpendicular to the longitudinal direction of the laminate at 140 ° C. using a tenter stretching machine (stretching treatment). By the said extending | stretching, the thickness of the PVA-type resin layer became 2.5 micrometers.
The laminated body which has the structure of the process protective film A / base material / PVA type-resin layer was bonded together to the base material side of this laminated body, and the process protective film A of the manufacture example 1 was bonded together.
The obtained laminate was immersed in a dyeing bath (an aqueous solution having an iodine concentration of 1.4% by weight and a potassium iodide concentration of 9.8% by weight) at a liquid temperature of 25 ° C. for 12 seconds and dyed (dyeing treatment).
Next, the laminate was immersed in a cleaning bath (pure water) having a liquid temperature of 25 ° C. for 6 seconds (first cleaning treatment).
Subsequently, it was immersed in a crosslinking bath (an aqueous solution having a boron concentration of 1% by weight and a potassium iodide concentration of 1% by weight) at a liquid temperature of 60 ° C. for 16 seconds (crosslinking treatment).
Next, the laminate was immersed for 3 seconds in a washing bath (aqueous solution having a potassium iodide concentration of 1% by weight) having a liquid temperature of 25 ° C. (second washing treatment).
Next, the laminate was dried in an oven at 60 ° C. for 21 seconds (first drying treatment), and further dried in an oven at 50 ° C. for 60 seconds (second drying treatment).
Finally, the process protective film A was peeled and removed to obtain a laminate having a base material / polarizer (thickness: 2.5 μm) structure.
The obtained laminate was subjected to the evaluations (2) to (4) above. The results are shown in Table 1.
［実施例２］
　実施例１と同様にして基材／ＰＶＡ系樹脂層（厚み６μｍ）の構成を有する積層体を作製し、この積層体を実施例１と同様に延伸して基材／ＰＶＡ系樹脂層（厚み１．２μｍ）の構成を有する積層体を作製した。この積層体のＰＶＡ系樹脂層側に輝度向上フィルム（日東電工社製、製品名「ＡＰＦ－Ｖ３」）を貼り合わせ、次いで、基材を剥離除去して、輝度向上フィルム／ＰＶＡ系樹脂層（厚み１．２μｍ）の構成を有する積層体を作製した。この積層体を用いたこと以外は実施例１と同様にして、輝度向上フィルム／偏光子（厚み１．２μｍ）の構成を有する積層体を作製した。得られた積層体を実施例１と同様の評価に供した。結果を表１に示す。 [Example 2]
A laminate having the structure of a base material / PVA resin layer (thickness 6 μm) was produced in the same manner as in Example 1, and this laminate was stretched in the same manner as in Example 1 to obtain a base material / PVA resin layer (thickness). A laminate having a structure of 1.2 μm) was produced. A brightness enhancement film (manufactured by Nitto Denko Corporation, product name “APF-V3”) is bonded to the PVA resin layer side of the laminate, and then the substrate is peeled and removed to obtain a brightness enhancement film / PVA resin layer ( A laminate having a thickness of 1.2 μm was produced. A laminate having the structure of a brightness enhancement film / polarizer (thickness: 1.2 μm) was produced in the same manner as in Example 1 except that this laminate was used. The obtained laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.
［実施例３］
　製造例２の工程保護フィルムＢを用いたこと以外は実施例１と同様にして、基材／偏光子（厚み２．５μｍ）の構成を有する積層体を作製した。得られた積層体を実施例１と同様の評価に供した。結果を表１に示す。 [Example 3]
A laminate having the structure of substrate / polarizer (thickness 2.5 μm) was produced in the same manner as in Example 1 except that the process protective film B of Production Example 2 was used. The obtained laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.
［比較例１］
　製造例３の工程保護フィルムＣを用いたこと以外は実施例１と同様にして、基材／偏光子（厚み２．５μｍ）の構成を有する積層体を作製した。得られた積層体を実施例１と同様の評価に供した。結果を表１に示す。 [Comparative Example 1]
Except having used the process protection film C of the manufacture example 3, it carried out similarly to Example 1, and produced the laminated body which has a structure of a base material / polarizer (thickness 2.5 micrometers). The obtained laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.
［比較例２］
　製造例４の工程保護フィルムＤを用いたこと以外は実施例１と同様にして、基材／偏光子（厚み２．５μｍ）の構成を有する積層体を作製した。得られた積層体を実施例１と同様の評価に供した。結果を表１に示す。 [Comparative Example 2]
A laminate having the structure of a substrate / polarizer (thickness: 2.5 μm) was produced in the same manner as in Example 1 except that the process protective film D of Production Example 4 was used. The obtained laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.
［比較例３］
　製造例５の工程保護フィルムＥを用いたこと以外は実施例１と同様にして、基材／偏光子（厚み２．５μｍ）の構成を有する積層体を作製した。得られた積層体を実施例１と同様の評価に供した。結果を表１に示す。 [Comparative Example 3]
A laminate having the structure of a base material / polarizer (thickness: 2.5 μm) was produced in the same manner as in Example 1 except that the process protective film E of Production Example 5 was used. The obtained laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.
［比較例４］
　工程保護フィルムを用いなかったこと以外は実施例１と同様にして、基材／偏光子（厚み２．５μｍ）の構成を有する積層体を作製した。得られた積層体を実施例１と同様の評価に供した。結果を表１に示す。 [Comparative Example 4]
A laminate having the structure of substrate / polarizer (thickness: 2.5 μm) was produced in the same manner as in Example 1 except that the process protective film was not used. The obtained laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１から明らかなように、本発明の実施例の製造方法によれば、製造工程中の工程保護フィルムの剥がれおよび偏光子のカール、ならびに工程保護フィルムの貼り換え時の偏光子の破断を良好に防止することができる。 As is clear from Table 1, according to the production method of the example of the present invention, the peeling of the process protective film and the curl of the polarizer during the production process, and the breakage of the polarizer when the process protective film is replaced are good. Can be prevented.
　本発明の製造方法により得られた偏光子は、液晶テレビ、液晶ディスプレイ、携帯電話、デジタルカメラ、ビデオカメラ、携帯ゲーム機、カーナビゲーション、コピー機、プリンター、ファックス、時計、電子レンジ等の液晶パネルに幅広く適用させることができる。 Polarizers obtained by the manufacturing method of the present invention are used for liquid crystal panels such as liquid crystal televisions, liquid crystal displays, mobile phones, digital cameras, video cameras, portable game machines, car navigation systems, copy machines, printers, fax machines, watches, and microwave ovens. Can be widely applied to.

Claims (4)

  1. 　ポリビニルアルコール系樹脂層と基材とを含む積層体の該基材側に工程保護フィルムを剥離可能に仮着すること、および、
    　該工程保護フィルムが仮着された積層体を染色して、該ポリビニルアルコール系樹脂層を偏光子とすること、を含み、
    　該ポリビニルアルコール系樹脂層の厚みが５μｍ以下であり、該基材の厚みが４０μｍ以下であり、該積層体の総厚みＴ１が４５μｍ以下であり、
    　該工程保護フィルムの低速剥離力が０．１２（Ｎ／２５ｍｍ）以上であり、
    　該積層体の総厚みＴ１と該工程保護フィルムの厚みＴ２とが下記式（１）の関係を満たす、偏光子の製造方法：
    　　　　Ｔ１／Ｔ２≦１．０　　・・・（１）。     Temporarily attaching the process protective film to the substrate side of the laminate including the polyvinyl alcohol-based resin layer and the substrate so as to be peelable; and
    Dyeing the laminate on which the process protective film is temporarily attached, and using the polyvinyl alcohol-based resin layer as a polarizer,
    The polyvinyl alcohol-based resin layer has a thickness of 5 μm or less, the base material has a thickness of 40 μm or less, and the total thickness T1 of the laminate is 45 μm or less,
    The low-speed peel force of the process protective film is 0.12 (N / 25 mm) or more,
    A method for producing a polarizer, wherein the total thickness T1 of the laminate and the thickness T2 of the process protective film satisfy the relationship of the following formula (1):
    T1 / T2 ≦ 1.0 (1).
  2. 　前記工程保護フィルムの高速剥離力が、前記低速剥離力の５倍以下である、請求項１に記載の製造方法。 The manufacturing method according to claim 1, wherein the high-speed peeling force of the process protective film is 5 times or less of the low-speed peeling force.
  3. 　前記ポリビニルアルコール系樹脂層が、前記工程保護フィルムを前記積層体に仮着する前に延伸されている、請求項１または２に記載の製造方法。 The manufacturing method according to claim 1 or 2, wherein the polyvinyl alcohol-based resin layer is stretched before temporarily attaching the process protective film to the laminate.
  4. 　前記基材が光学機能フィルムである、請求項１から３のいずれかに記載の製造方法。 The manufacturing method according to any one of claims 1 to 3, wherein the substrate is an optical functional film.
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