WO2015159645A1 - Plaque de polarisation et dispositif d'affichage à cristaux liquides - Google Patents

Plaque de polarisation et dispositif d'affichage à cristaux liquides Download PDF

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Publication number
WO2015159645A1
WO2015159645A1 PCT/JP2015/058461 JP2015058461W WO2015159645A1 WO 2015159645 A1 WO2015159645 A1 WO 2015159645A1 JP 2015058461 W JP2015058461 W JP 2015058461W WO 2015159645 A1 WO2015159645 A1 WO 2015159645A1
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polarizing plate
protective film
film
plate protective
polarizer
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PCT/JP2015/058461
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English (en)
Japanese (ja)
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美典 玉川
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コニカミノルタ株式会社
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Priority to KR1020167028297A priority Critical patent/KR20160132453A/ko
Priority to JP2016513684A priority patent/JPWO2015159645A1/ja
Publication of WO2015159645A1 publication Critical patent/WO2015159645A1/fr

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • 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
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133528—Polarisers

Definitions

  • the present invention relates to a polarizing plate and a liquid crystal display device. More specifically, the present invention relates to a polarizing plate having high polarizer stability and a liquid crystal display device having the polarizing plate and having excellent bend unevenness resistance.
  • the liquid crystal display device is composed of a liquid crystal cell having a structure in which a transparent electrode, a liquid crystal layer, a color filter, etc. are sandwiched between a pair of glass plates, and two polarizing plates provided on the surface side of each glass plate, Each polarizing plate is sandwiched between, for example, an optical film having two polarizers made of a polyvinyl alcohol-based resin, for example, a polarizing plate protective film located outside and a retardation film disposed on the liquid crystal cell side. It has been configured.
  • a polarizing plate protective film constituting this polarizing plate mainly, it has high transparency, saponification treatment with an alkaline aqueous solution, and using a polyvinyl alcohol-based adhesive, good adhesion with a polarizer is obtained.
  • Cellulose ester films have been mainly used because they are easy to be formed.
  • the polarizing plate protective film is a thin film that is insufficient to prevent polarizer deterioration, and further improvements are made. It turned out to be necessary.
  • thinning the glass plate used in the liquid crystal cell has a great effect on the thinning of the display device and is in the direction of adoption.
  • thinning the glass plate newly causes bend unevenness. It is coming. Bend unevenness is a phenomenon in which bending due to contraction and extension occurs in a polarizer or the like composed of a polyvinyl alcohol resin due to humidity fluctuations in a high or low humidity environment, and as a result, display unevenness develops. It has been found that this phenomenon tends to occur when the glass plate is thinned.
  • the present invention has been made in view of the above-described problems and situations, and a solution to the problem is a polarizing plate having high polarizer stability and display unevenness (bend unevenness) when stored in a high temperature and high humidity environment. It is an object of the present invention to provide a liquid crystal display device in which the occurrence of the above is suppressed.
  • the present inventor has a structure in which a polarizer composed of a polyvinyl alcohol-based resin is sandwiched between a polarizing plate protective film and a retardation film in the course of examining the cause of the above-described problem.
  • a polarizing plate wherein the polarizing plate protective film contains a copolymer (A) of at least an aromatic vinyl monomer and an unsaturated carboxylic acid monomer or an unsaturated dicarboxylic acid anhydride monomer, and the film thickness is specified.
  • the polarizer has a high polarizer stability when stored in a high-temperature and high-humidity environment, and is a liquid crystal. It has been found that a polarizing plate capable of suppressing the occurrence of display unevenness (bend unevenness) when provided in a display device is obtained.
  • a polarizer composed of a polyvinyl alcohol-based resin, a polarizing plate configured to be sandwiched between a polarizing plate protective film and a retardation film
  • the polarizing plate protective film contains a copolymer (A) of an aromatic vinyl monomer and an unsaturated carboxylic acid monomer or an unsaturated dicarboxylic acid anhydride monomer, and has a thickness in the range of 20 to 60 ⁇ m.
  • a polarizing plate, wherein the polarizer has a thickness in the range of 5.0 to 15 ⁇ m.
  • the polarizing plate protective film further comprises an acid, alcohol, metal salt, nonionic surfactant, and nonreactive quaternary ammonium salt type surfactant having a linear or branched alkyl group having 8 to 22 carbon atoms. 2. At least one compound selected from agents is contained within a range of 0.1 to 1.0% by mass with respect to the total mass of the copolymer (A). Polarizer.
  • the polarizing plate protective film further comprises at least one selected from core / shell type acrylic fine particles, styrene-butadiene copolymer, styrene-conjugated diene copolymer, and butyl acrylate compound.
  • the polarizing plate according to any one of items 1 to 5, which is contained within a range of 0.5 to 5.0% by mass with respect to the total mass of
  • the degree of decrease in the degree of polarization (%) represented by the following formula (1) of the sample subjected to the forced degradation treatment for 120 hours in an environment of 80 ° C. and 90% RH with respect to the untreated sample is 1.0% or less.
  • the polarizing plate according to any one of items 1 to 8 is provided on at least one surface side of a liquid crystal cell having a glass plate having a thickness in the range of 0.3 to 0.7 mm on the surface.
  • a liquid crystal display device comprising a retardation film surface constituting the polarizing plate and the glass plate bonded together.
  • the polarizing plate protective film disposed at a position adjacent to the polarizer contains at least a copolymer of an aromatic vinyl monomer and an unsaturated carboxylic acid monomer or an unsaturated dicarboxylic anhydride monomer. It is characterized by doing.
  • a film composed of a resin having a large amount of hydroxy groups such as cellulose ester is likely to contain moisture, and when a polarizing plate is constructed, it affects the adjacent polarizers and the like. Become.
  • display unevenness unevenness
  • the stability of the polarizer in a high-temperature and high-humidity environment is reduced.
  • the improvement in (bend unevenness) and the stability of the polarizer could not be achieved at the same time.
  • the hydroxyl group of each carboxylic acid monomer is hydrogen-bonded, thereby causing moisture in the film.
  • the presence of the hydroxy group prevents the pH fluctuation of the adjacent polarizer, prevents the collapse of cross-linking by boric acid, etc., and high polarizer stability Can be realized.
  • the heat resistance can be improved due to the presence of the hydroxy group interaction.
  • a polarizing plate protective film having a film thickness in the range of 20 to 60 ⁇ m can be constituted by a copolymer (A) of an aromatic vinyl monomer and an unsaturated carboxylic acid monomer or an unsaturated dicarboxylic acid anhydride monomer. Based on excellent water resistance and heat resistance, even if the polarizer is thinned (within a thickness of 5.0 to 15 ⁇ m), the deterioration and shrinkage of the polarizer can be suppressed. As a result, the liquid crystal display device When incorporated in the liquid crystal display, the liquid crystal panel is less likely to warp and display unevenness (bend unevenness) can be improved.
  • Schematic sectional view showing an example of the configuration of a polarizing plate provided with a polarizing plate protective film Schematic sectional view showing a part of the configuration of a liquid crystal display device provided with a polarizing plate
  • the polarizing plate of the present invention has a configuration in which a polarizer made of polyvinyl alcohol resin is sandwiched between a polarizing plate protective film and a retardation film, and the polarizing plate protective film comprises at least an aromatic vinyl monomer and an unsaturated carboxylic acid. Containing a copolymer (A) with an acid monomer or an unsaturated dicarboxylic acid anhydride monomer, the film thickness being in the range of 20-60 ⁇ m, and the film thickness of the polarizer being in the range of 5.0-15 ⁇ m It is characterized by being within.
  • This feature is a technical feature common to the inventions according to claims 1 to 10.
  • a polarizing plate protective film is further used as a peeling aid from the viewpoint of more manifesting the intended effect of the present invention, and a linear or branched alkyl group having 8 to 22 carbon atoms.
  • At least one compound selected from acids, alcohols, metal salts, nonionic surfactants and nonreactive quaternary ammonium salt type surfactants having the following, with respect to the total mass of the copolymer (A):
  • a copolymer (A) composed of an aromatic vinyl monomer and an unsaturated carboxylic acid monomer or an unsaturated dicarboxylic anhydride monomer is contained in the range of 0.1 to 1.0% by mass.
  • the aromatic vinyl monomer contained in the polarizing plate protective film is styrene in that a polarizing plate having more excellent heat resistance and polarizer stability can be obtained.
  • the unsaturated carboxylic acid monomer contained in the protective film for polarizing plate is methacrylic acid, or the unsaturated dicarboxylic acid anhydride monomer is maleic anhydride. It is preferable at the point which can obtain the polarizing plate which has child stability.
  • the polarizing plate protective film further comprises at least one selected from core / shell type acrylic fine particles, styrene-butadiene copolymer, styrene-conjugated diene copolymer and butyl acrylate compound.
  • the content within the range of 0.5 to 5.0% by mass with respect to the total mass of (A) is preferable from the viewpoint of obtaining a polarizing plate protective film having excellent brittleness resistance and toughness.
  • the polarizing plate protective film and the polarizer are bonded with an active energy ray-curable adhesive, and even in the polarizing plate protective film produced using an aromatic vinyl monomer, the polarizer and the stable It is preferable from the standpoint that a polarizing plate having excellent adhesion can be produced without causing delamination and that a desired degree of polarization stability can be obtained.
  • the degree of decrease in the degree of polarization (%) represented by the formula (1) in the sample after being stored for 120 hours in an environment of 80 ° C. and 90% RH is 1.0%
  • the polarizing plate of the present invention is formed on at least one surface side of a liquid crystal cell having a glass plate having a thickness in the range of 0.3 to 0.7 mm on the surface.
  • the retardation film surface to be bonded and the glass plate are bonded to each other.
  • the polarizing plate of the present invention is disposed on both surfaces of the liquid crystal cell, and the retardation film surface and the glass plate constituting the polarizing plate. Is preferable from the viewpoint that the characteristics of the polarizing plate of the present invention can be sufficiently exhibited and display unevenness (bend unevenness) of the liquid crystal display device can be suppressed due to high water resistance.
  • ⁇ is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.
  • the polarizing plate of the present invention is characterized by having a polarizing plate protective film having a specific configuration and a polarizer.
  • the polarizing plate of the present invention preferably has a configuration in which a polarizer is sandwiched between a polarizing plate protective film and a retardation film, and the polarizing plate protective film and the polarizer are bonded by an active energy ray-curable adhesive. It is a preferable aspect that it is the structure which has an active energy ray hardening-type resin layer to do.
  • FIG. 1 is a schematic sectional view showing an example of the configuration of a polarizing plate provided with a polarizing plate protective film according to the present invention.
  • a polarizing plate 101 has a polarizing plate protective film 102 containing a copolymer (A) of an aromatic vinyl monomer and an unsaturated carboxylic acid monomer or an unsaturated dicarboxylic anhydride monomer on the surface side. and, in its lower part has a radiation-curable resin layer 103A 1.
  • the radiation-curable resin layer 103A 1 is a layer that functions to adhere the polarizer protective film 102 and the polarizer 104 configured, the active energy ray, for example, a material that is cured by irradiating ultraviolet rays or the like Has been.
  • the thickness of the polarizing plate protective film 102 is in the range of 20 to 60 ⁇ m, and the thickness of the polarizer 104 is in the range of 5.0 to 15 ⁇ m. To do.
  • a certain retardation value is laminated to constitute the polarizing plate 101.
  • the polarizing plate protective film according to the present invention is disposed on the surface side opposite to the surface in contact with the liquid crystal cell with the polarizer in between when constituting the polarizing plate.
  • the surface in contact with the liquid crystal cell in the present invention is the lower surface of the retardation film 105, which will be described in detail later with reference to FIG. 2, and is opposite to the surface with the polarizer 104 interposed therebetween.
  • the polarizing plate protective film 102 according to the present invention is installed on the surface. That is, the polarizing plate protective film which concerns on this invention is an optical film located in the surface side among two types of optical films which comprise the polarizing plate of this invention.
  • an antiglare layer for example, an antiglare layer, an antireflection layer, an antifouling layer may be used as necessary.
  • Various functional layers such as a hard coat layer may be provided.
  • the polarizing plate of the present invention is disposed on at least one surface side of a liquid crystal cell having a glass plate having a thickness in the range of 0.3 to 0.7 mm on the surface. Is characterized in that the retardation film surface and the glass plate are laminated, and as a more preferred embodiment, the polarizing plate of the present invention is arranged on both surfaces of the liquid crystal cell to constitute the polarizing plate. It is a preferable configuration that the retardation film surface and the glass plate are bonded together.
  • FIG. 2 is a schematic cross-sectional view showing an example of the configuration of the polarizing plate panel 106 provided with the polarizing plate 101 of the present invention described above.
  • the configuration in which the polarizing plates are arranged on both surfaces of the liquid crystal cell is shown as an example. .
  • a polarizing plate panel 106 is formed by sandwiching the liquid crystal cell 107 between the retardation film 105A constituting the polarizing plate 101A described in FIG. 1 and the retardation film 105B constituting the polarizing plate 101B. Yes.
  • the liquid crystal cell 107 has a configuration in which glass plates 109 ⁇ / b> A and 109 ⁇ / b> B are disposed on both surfaces of the liquid crystal layer 108.
  • the polarizing plate protective film 102A in the polarizing plate 101A on the upper surface side of the liquid crystal cell 107, is disposed on the surface portion as an optical film. Further, a retardation film 105A is disposed below the polarizer 104A, and this is referred to as a retardation film T2.
  • the polarizing plate 101A, the polarizing plate protective film 102A and the polarizer 104A is, are bonded through a radiation-curable resin layer 103A 1, similarly retardation film 105A and the polarizer 104A is active energy ray They are bonded through the cured resin layer 103A 2.
  • the retardation film 105A and the glass plate 109A of the liquid crystal cell 107 are bonded via an adhesive layer or the like.
  • a polarizing plate 101B is disposed on the opposite surface of the liquid crystal cell 107, and a polarizing plate protective film 102B is disposed as an optical film from the outermost surface. In the present invention, this is referred to as a polarizing plate protective film T4. Further, a retardation film 105B is disposed on the liquid crystal cell side of the polarizer 104B, and this is referred to as a retardation film T3.
  • the polarizing plate 101B, a polarizing plate protective film 102B and the polarizer 104B is, are bonded through a radiation-curable resin layer 103B 1, the polarizer 104B is similarly to the retardation film 105B, an active energy ray They are bonded through the cured resin layer 103B 2.
  • the retardation film 105B and the glass plate 109B of the liquid crystal cell 107 are bonded via an adhesive layer or the like.
  • the polarizing plate having the polarizing plate protective film defined in the present invention is disposed on at least one surface side of the liquid crystal cell 107, and on the other side, the polarizing plate is not applicable to the present invention.
  • both of the polarizing plates 101A and 101B arranged on both surfaces of the liquid crystal cell 107 are polarizing plates having the characteristics defined in the present invention.
  • the polarizing plate protective film according to the present invention is characterized by containing a copolymer (A) of an aromatic vinyl monomer and an unsaturated carboxylic acid monomer or an unsaturated dicarboxylic acid anhydride monomer.
  • the polarizing plate protective film according to the present invention is characterized by containing the copolymer (A).
  • the copolymer (A) Preferably, 30 mol% or more of the thermoplastic resin constituting the polarizing plate protective film is present in the present invention. It is preferable that it is comprised with the copolymer (A) which concerns on this, More preferably, it is 50 mol% or more, More preferably, it is 70 mol% or more, Most preferably, it is 90 mol% or more.
  • the monomer constituting the copolymer is also referred to as “to unit”.
  • the aromatic vinyl monomer has a function of increasing the water resistance of the copolymer (A).
  • the aromatic vinyl monomer is preferably a styrene compound.
  • the styrenic compound examples include styrene; alkyl-substituted styrenes such as ⁇ -methylstyrene, ⁇ -methylstyrene, and p-methylstyrene; halogen-substituted styrenes such as 4-chlorostyrene and 4-bromostyrene; p- Hydroxystyrenes such as hydroxystyrene, ⁇ -methyl-p-hydroxystyrene, 2-methyl-4-hydroxystyrene, 3,4-dihydroxystyrene; vinylbenzyl alcohols; p-methoxystyrene, p-tert-butoxystyrene, alkoxy-substituted styrenes such as m-tert-butoxystyrene; vinyl benzoic acids such as 3-vinylbenzoic acid and 4-vinylbenzoic acid; 4-vinylbenzyl acetate
  • styrene and ⁇ -methylstyrene are preferable, and styrene is particularly preferable because it is compatible with other styrene resins and (meth) acrylic resins.
  • aromatic vinyl monomers may be used alone or in combination of two or more.
  • Examples of the unsaturated carboxylic acid monomer applicable to the present invention include acrylic acid, acetylene carboxylic acid, 1-adamantal carboxylic acid, benzoic acid, desodium benzoate, 9-anthracene carboxylic acid, isopentanoic acid, isobutyric acid, Undecanoic acid, 10-undecanoic acid, 4-ethylbenzoic acid, ethyl oleic acid, 2-ethylhexanoic acid, 2-ethylbutyric acid, octanoic acid, formic acid, crotonic acid, cinnamic acid, acetic acid, tetramethylammonium acetate, cyclobutanecarboxylic Acid, cyclopropanecarboxylic acid, cyclopropylacetic acid, cyclohexanecarboxylic acid, cyclopentanecarboxylic acid, diphenylacetic acid, 2,4-dimethylbenz
  • unsaturated dicarboxylic acid anhydride monomers include maleic acid anhydride, methylmaleic acid anhydride, 1,2-dimethylmaleic acid anhydride, ethylmaleic acid anhydride, and phenylmaleic acid anhydride.
  • Examples of such other copolymerizable monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethyl (meth) acrylate, and 2-ethylhexyl.
  • Examples thereof include alkyl (meth) acrylates such as methacrylate, maleimides such as N-phenylmaleimide, N-methylmaleimide and N-cyclohexylmaleimide, and glycidyl group-containing monomers such as glycidyl methacrylate.
  • alkyl (meth) acrylates such as methyl (meth) acrylate are preferable.
  • Other monomer components may be used alone or in combination of two or more.
  • the copolymer (A) has at least an aromatic vinyl monomer and an unsaturated carboxylic acid monomer or an unsaturated dicarboxylic anhydride monomer, and the aromatic vinyl in the copolymer (A).
  • the monomer ratio is preferably in the range of 5 to 95 mol%, more preferably in the range of 30 to 95 mol%, still more preferably in the range of 50 to 95 mol%, and particularly preferably 75. Within the range of ⁇ 90 mol%.
  • the ratio of the unsaturated carboxylic acid monomer or the unsaturated dicarboxylic acid anhydride monomer is in the range of 5 to 95 mol%, more preferably in the range of 5 to 70 mol%, still more preferably 5 to 50 mol%. And particularly preferably in the range of 10 to 25 mol%.
  • the other monomer can be selected in a range that does not impair the object effects of the invention, and can be copolymerized, for example, in the range of 0 to 30 mol%.
  • Synthesis of copolymer (A) A well-known manufacturing method can be used for preparation of the copolymer (A) based on this invention.
  • general polymerization methods for unsaturated carboxylic acid polymers include radical solution polymerization using radical heat and initiator, radical suspension polymerization, radical emulsion polymerization, anionic polymerization using organometallic compounds, and transition metal complexes. Examples thereof include coordination anionic polymerization, cationic polymerization using Lewis acid, and the like.
  • Examples of the synthesis method using an aromatic vinyl monomer and an unsaturated carboxylic acid monomer or an unsaturated dicarboxylic anhydride monomer include, for example, JP-A-7-011081, JP-A-7-118508, 7-216184, JP-A-9-302173, JP-A-11-106579, JP-A-11-16751, JP-A 2000-178385, JP-A 2004-204064, JP-A 2004-2004. No. 3004344, JP-A No. 2004-339282, JP-A No. 2005-290207, JP-A No. 2006-124523, JP-A 2009-185141, JP-A 2010-024452, JP-A 2013-104402. It can be prepared with reference to the synthesis method described in the publication Kill.
  • the molecular weight of the copolymer (A) according to the present invention is preferably in the range of 50,000 to 450,000, preferably in the range of 100,000 to 400,000, as the weight average molecular weight measured by GPC described below. More preferably, it is more preferably in the range of 150,000 to 300,000.
  • the weight average molecular weight is 450,000 or less, it is easy to dissolve in a solvent when forming a film by the solution casting method, and sufficient fluidity can be obtained when forming a film by the melt casting method. it can. Moreover, if a weight average molecular weight is 50,000 or more, the drawing process suitability can be obtained.
  • the weight average molecular weight (Mw) of the copolymer (A) according to the present invention is gel permeation chromatography (HLC8220GPC manufactured by Tosoh Corporation), column (TSK-GEL G6000HXL-G5000HXL-G5000HXL-G4000HXL-G3000HXL series) manufactured by Tosoh Corporation. Can be measured.
  • copolymer (A) 20 ⁇ 0.5 mg is dissolved in 10 ml of tetrahydrofuran and filtered through a 0.45 mm filter. 100 ml of this filtrate is injected into the above column having a column temperature of 40 ° C., measured at a detector RI temperature of 40 ° C., and a weight average molecular weight in terms of styrene is measured.
  • the polarizing plate protective film according to the present invention is provided with, for example, a peeling aid, an antistatic agent, an antioxidant, an ultraviolet absorber, and slipperiness, as necessary, within a range that does not impair the object effects of the present invention.
  • Various additives such as fine particles (matting agent) and impact reinforcement for enhancing toughness can be further contained.
  • the polarizing plate protective film containing the aromatic vinyl (for example, styrene) copolymer according to the present invention has high adhesion to the metal support used when casting the dope in the film forming step. With respect to this phenomenon, for the purpose of stably peeling from the metal support, suppressing unnecessary elongation at the time of peeling, and uniforming the thickness of the resulting film, the polarizing plate protective film is provided with a peeling aid or a charge. It is preferable to contain an inhibitor.
  • the stripping aid is not particularly limited, but is an acid, alcohol, metal salt, nonionic surfactant, and nonreactive quaternary ammonium salt having a linear or branched alkyl group having 8 to 22 carbon atoms. It is possible to contain at least one compound selected from the type surfactants in the range of 0.1 to 1.0% by mass relative to the total mass of the copolymer (A) according to the present invention. It is preferable from the viewpoint of improving the peelability to the body.
  • Examples of the acid having a linear or branched alkyl group having 8 to 22 carbon atoms, which is the above-described peeling aid, include alkyl sulfonates and alkyl benzene sulfonates.
  • Examples of the salt include sodium salt, potassium salt, amine salt, ammonium salt, phosphonium salt and the like.
  • Specific examples include sodium decylsulfonate, sodium decylbenzenesulfonate, potassium decylbenzenesulfonate, sodium dodecylsulfonate, potassium dodecylsulfonate, sodium dodecylbenzenesulfonate, potassium dodecylbenzenesulfonate, tetrabutyl dodecylbenzenesulfonate.
  • Examples of the alcohol include, for example, octan-1-ol, nonan-1-ol, decan-1-ol, undecan-1-ol, dodecan-1-ol, tridecan-1-ol, and tetradecan-1-ol.
  • octadecan-1-ol stearyl alcohol is preferred.
  • nonionic surfactant examples include polyoxyalkylene glycols such as polyoxyethylene polyoxypropylene glycol, polyoxyalkylene styrenated phenyl ethers such as polyoxyethylene styrenated phenyl ether, and polyoxyethylene tridecyl ether.
  • nonionic surfactants such as polyoxyalkylene glycols such as polyoxyethylene lauryl ether, polyoxyethylene sorbitan monococoate, polyoxyethylene sorbitan monostearate and polyoxyalkylene fatty acid esters such as polyoxyethylene hydrogenated castor oil These may be used alone or in combination of two or more. Examples of these commercially available products include Epan manufactured by Daiichi Kogyo Seiyaku Co., Ltd., and electro stripper manufactured by Kao Corporation.
  • non-reactive quaternary ammonium salt type surfactant as a peeling aid, and among them, a non-reactive quaternary ammonium salt type surfactant having 2 or less methyl groups is useful.
  • the surfactant include non-reactive quaternary ammonium salt type surfactants having one methyl group, such as polyoxypropylene methyldiethylammonium chloride, methyldiethyl (2-methoxyethyl) ammonium chloride, octyl.
  • Examples include bispolyoxyethylene methylammonium chloride, lauryl bispolyoxyethylene methylammonium chloride, oleyl bispolyoxyethylene methylammonium chloride, and polyoxyethylene dodecyl monomethylammonium chloride.
  • Non-reactive quaternary ammonium having two methyl groups examples include aliphatic alkyl quaternary ammonium salts such as octyl dimethyl ethyl ammonium ethyl sulfate, lauryl dimethyl ethyl amine.
  • Nium ethyl sulfate, palmityldimethylethylammonium ethyl sulfate, didecyldimethylammonium chloride, distearyldimethylammonium chloride, lauryldimethylbenzylammonium chloride, stearyldimethylhydroxyethylammonium paratoluenesulfonate, alkylbenzyldimethylammonium chloride, ethyldimethyl (2- Methoxyethyl) ammonium chloride and the like are preferably used.
  • the surfactant contains an alkylene oxide group.
  • alkylene oxide group those contained in either or both of an anionic component and a cationic component of the surfactant can be used.
  • examples of those containing an alkylene oxide group include polyoxypropylene methyl diethyl ammonium chloride, methyl diethyl (2-methoxyethyl) ammonium chloride, octyl bis polyoxyethylene methyl ammonium chloride, and lauryl bis polyoxyethylene methyl ammonium chloride. It is also preferable to use oleyl bis polyoxyethylene methylammonium chloride, polyoxyethylene dodecyl monomethylammonium chloride, or ethyldimethyl (2-methoxyethyl) ammonium chloride. These surfactants may be used alone or in combination of two or more.
  • non-reactive quaternary ammonium salt type surfactants commercially available products can be used.
  • the trade name “ADEKA COAL CC-36” (number of methyl groups: 1, manufactured by ADEKA Corporation), “ADEKA COAL” CC-42 ”(number of methyl groups: 1 product, manufactured by ADEKA Corporation), trade name“ cationic L-207 ”(number of methyl groups: 1 product, manufactured by NOF Corporation), trade name“ Katiogen ES-L ”( Number of methyl groups: 2, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), trade name “Katiogen ES-O” (number of methyl groups: 2, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), trade name “Katiogen ES-OW” ( Number of methyl groups: 2 (Daiichi Kogyo Seiyaku Co., Ltd.), trade name “Katiogen ES-WS-L-9” (2
  • antioxidant In the polarizing plate protective film according to the present invention, a conventionally known antioxidant can be used for the purpose of imparting stability.
  • the antioxidant in particular, lactone, sulfur, phenol, double bond, hindered amine, and phosphorus compounds can be preferably used.
  • the phenolic compound preferably has a 2,6-dialkylphenol structure.
  • “Irganox 1076”, “Irganox 1010” commercially available from BASF Japan Ltd., and commercially available from ADEKA Corporation.
  • “Adeka Stub AO-50” etc. which can be mentioned.
  • Examples of the phosphorus compound include “Sumizer GP” commercially available from Sumitomo Chemical Co., Ltd., “ADK STAB PEP-24G”, “ADK STAB PEP-36”, and “ADK STAB 3010” commercially available from ADEKA Corporation.
  • “IRGAFOS P-EPQ” commercially available from BASF Japan Ltd.
  • “GSY-P101” commercially available from Sakai Chemical Industry Co., Ltd.
  • Irgafos XP40, Irgafos XP60 commercially available from BASF Japan Ltd., etc. Is mentioned.
  • hindered amine compound examples include “Tinvin 144” and “Tinvin 770” commercially available from BASF Japan, and “ADK STAB LA-52” commercially available from ADEKA.
  • sulfur compound examples include “Sumilizer TPL-R” and “Sumilizer TP-D” commercially available from Sumitomo Chemical Co., Ltd.
  • the above-mentioned double bond compound is commercially available from Sumitomo Chemical Co., Ltd. under the trade names of “Sumilizer GM” and “Sumilizer GS”.
  • the polarizing plate protective film according to the present invention preferably contains an ultraviolet absorber from the viewpoint of improving the weather resistance.
  • ultraviolet absorbers include benzotriazole-based, 2-hydroxybenzophenone-based, and salicylic acid.
  • ultraviolet absorbers such as phenyl ester and triazine.
  • 2- (5-methyl-2-hydroxyphenyl) benzotriazole 2- [2-hydroxy-3,5-bis ( ⁇ , ⁇ -dimethylbenzyl) phenyl] -2H-benzotriazole
  • 2- (3 Triazoles such as 5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone And benzophenones.
  • UV absorbers Commercially available products of these ultraviolet absorbers may be used, for example, Tinuvin 109, Tinuvin 171, Tinuvin 234, Tinuvin 326, Tinuvin 327, Tinuvin 328, Tinuvin 928, etc. manufactured by BASF Japan, or 2,2 '-Methylenebis [6- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol] (molecular weight 659; examples of commercially available products are manufactured by ADEKA Corporation LA31) can be preferably used.
  • UV absorbers having a molecular weight of 400 or more are less likely to volatilize at a high boiling point and are difficult to disperse during high temperature molding of a polarizing plate protective film. It is preferable from the viewpoint of imparting the property.
  • the ultraviolet absorber having a molecular weight of 400 or more partially overlaps with the above-mentioned exemplary compounds.
  • 2- [2-hydroxy-3,5-bis ( ⁇ , ⁇ -dimethylbenzyl) phenyl] -2- Benzotriazoles such as benzotriazole, 2,2-methylenebis [4- (1,1,3,3-tetrabutyl) -6- (2H-benzotriazol-2-yl) phenol], bis (2,2,6 , 6-tetramethyl-4-piperidyl) sebacate, hindered amines such as bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, and 2- (3,5-di-t-butyl) -4-hydroxybenzyl) -2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl), 1- [2- [3- (3,5-di-t- Butyl Molecules such as 4-hydroxyphenyl)
  • 2- [2-hydroxy-3,5-bis ( ⁇ , ⁇ -dimethylbenzyl) phenyl] -2-benzotriazole and 2,2-methylenebis [4- (1,1,3,3- Tetrabutyl) -6- (2H-benzotriazol-2-yl) phenol] is particularly preferred.
  • a matting agent in the polarizing plate protective film according to the present invention, a matting agent can be added for the purpose of imparting slipperiness.
  • any inorganic compound or organic compound may be used as long as it is a material that does not impair the transparency of the obtained polarizing plate protective film and has heat resistance in the film forming process.
  • These matting agents can be used alone or in combination of two or more.
  • silicon dioxide fine particles are particularly preferably used from the viewpoint of excellent transparency (haze).
  • silicon dioxide fine particles include Aerosil 200V, Aerosil R972V, Aerosil R972, R974, R812, 200, 300, R202, OX50, TT600, NAX50 (above, Nippon Aerosil Co., Ltd.), Sea Hoster KEP-10, Sea Hoster Trade names such as KEP-30, Seahoster KEP-50 (Nippon Shokubai Co., Ltd.), Silo Hovic 100 (Fuji Silysia), Nip Seal E220A (Nihon Silica Kogyo), Admafine SO (Admatex) A commercially available product having the same can be preferably used.
  • the shape of the matting agent particles can be used without any particular limitation, such as indefinite shape, needle shape, flat shape, and spherical shape.
  • the use of spherical particles is particularly preferable because a film having high transparency can be obtained.
  • the size of the matting agent particles is preferably smaller than the wavelength of visible light because the light is scattered and the transparency is lowered when the particle size is close to the wavelength of visible light. It is preferable that it is 2 or less. However, if the size of the matting agent particles is too small, the effect of improving the slipping property may not be exhibited. Therefore, the particle diameter is particularly preferably in the range of 80 to 180 nm.
  • the particle size means the size of the aggregate when the particle is an aggregate of primary particles.
  • a particle when a particle is not spherical, it means the diameter of a circle corresponding to the projected area.
  • the polarizing plate protective film according to the present invention may contain core / shell type acrylic fine particles, styrene-conjugated diene compound or butyl acrylate compound as an impact reinforcing material in order to enhance impact resistance.
  • the core-shell type acrylic fine particles are obtained by polymerizing a mixture of 80 to 98.9% by mass of methyl methacrylate, 1 to 20% by mass of alkyl acrylate and 0.01 to 0.3% by mass of a polyfunctional grafting agent.
  • the styrene-conjugated diene compound is preferably a styrene-butadiene copolymer.
  • the copolymer may be a rubbery elastic body or elastic organic fine particles. Specifically, it is preferably a core / shell type elastic organic fine particle.
  • the core part is preferably composed of a soft polymer; and the shell part covering the periphery of the core part is preferably composed of another polymer having high compatibility with the copolymer according to the present invention and other resins.
  • the soft polymer includes a structural unit derived from a conjugated diene monomer and, if necessary, a structural unit derived from another monomer.
  • the conjugated diene monomer include 1,3-butadiene (hereinafter sometimes simply referred to as “butadiene”), isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, -Chloro-1,3-butadiene, myrcene and the like are included, and butadiene and isoprene are preferable.
  • Examples of other monomers include styrene components such as styrene and ⁇ -methylstyrene.
  • the content ratio of the structural unit derived from the conjugated diene monomer in the soft polymer is usually 50% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more.
  • Examples of other polymers include copolymers of acrylonitrile and styrene, and polymers mainly composed of methacrylic acid esters such as methyl methacrylate.
  • the volume average particle diameter of the elastic organic fine particles is preferably 0.35 ⁇ m or less, more preferably in the range of 0.01 to 0.35 ⁇ m, and still more preferably in the range of 0.05 to 0.30 ⁇ m. is there. If the volume average particle diameter is 0.01 ⁇ m or more, sufficient impact absorbability can be imparted to the film, and if the volume average particle diameter is 0.35 ⁇ m or less, the transparency of the resulting film is unlikely to be impaired.
  • Examples of commercially available elastic organic fine particles include Methbrene C-140A and C-215A (manufactured by Mitsubishi Rayon Co., Ltd.), Tuffprene 126, Asaflex 800, Asaflex 825 (manufactured by Asahi Kasei Chemicals Corporation). , TR2000, TR2250 (above, manufactured by JSR Corporation) and the like.
  • Examples of other rubber-like elastic bodies include acrylate-based rubber-like polymers, and rubber-like polymers containing acrylate-based polymers containing butyl acrylate as the main component are preferred.
  • the rubber-like elastic body using butyl acrylate may be an elastic body particle or a structure in which two kinds of polymers are layered.
  • a typical example is a grafted rubber elastic component of alkyl acrylate such as butyl acrylate and styrene, and a hard resin layer made of polymethyl methacrylate or a copolymer of methyl methacrylate and alkyl acrylate to form a layer with a core / shell structure.
  • elastic particles are examples of elastic particles.
  • the content of the impact reinforcing material is preferably 0.1 to 10% by mass, and more preferably 1 to 5% by mass with respect to the total amount with the copolymer (A) and other resins.
  • the refractive index is the same as that of the styrene-acrylonitrile copolymer used in the present invention, or the difference in refractive index is within a range of ⁇ 0.01. It is preferable from the viewpoint that the transparency of the film can be maintained.
  • the degree of polarization obtained by the lower formula (1) of the untreated polarizing plate is set to 1 (%), and the forced deterioration treatment is performed for 120 hours in an environment of 80 ° C. and 90% RH.
  • the degree of polarization obtained by the following formula (1) after application is defined as the degree of polarization 2
  • the degree of decrease in the degree of polarization represented by the following formula (2) is preferably 1.0% or less.
  • it is 1.0% or less including 0%, and particularly preferably 0.6% or less including 0%.
  • Degree of decrease in polarization degree (%) polarization degree 1 (%) ⁇ polarization degree 2 (%) Specifically, the degree of polarization in the present invention can be determined according to the following method.
  • thermoplastic resin constituting the polarizing plate protective film according to the present invention may be composed of a copolymer (A) of an aromatic vinyl monomer and an unsaturated carboxylic acid monomer or an unsaturated dicarboxylic anhydride monomer.
  • the polarizing plate protective film according to the present invention is an acid, alcohol, metal salt, nonionic surfactant and nonreactive quaternary ammonium salt having a linear or branched alkyl group having 8 to 22 carbon atoms.
  • polarizing plate protective film Containing at least one compound selected from type surfactants in a range of 0.1 to 1.0% by mass relative to the total mass of the copolymer (A), 3) Use of styrene as the aromatic vinyl monomer constituting the polarizing plate protective film, 4) Use methacrylic acid as the unsaturated carboxylic acid monomer contained in the polarizing plate protective film, or use maleic anhydride as the unsaturated dicarboxylic acid anhydride monomer, 5) The polarizing plate protective film and the polarizer are bonded with an active energy ray-curable adhesive, 6) Forming a polarizing plate protective film by a solution casting method, This can be achieved by appropriately selecting or combining the respective means.
  • the method of forming a film of a styrene-methacrylic acid copolymer by a solution film forming method prevents the penetration of moisture into the film by hydrogen bonding of hydroxy groups of methacrylic acid.
  • the group By the presence of the group, it is possible to suppress the pH fluctuation of the adjacent polarizer and to prevent the breakage of the cross-linking by boric acid, and by containing the highly hydrophobic styrene, High polarizer stability can be realized.
  • the film casting method can be preferably selected from a solution casting method or a melt casting method. Applying it can control the distribution state of the resin to suppress panel bend and obtain a uniform and smooth surface. Furthermore, the degree of polarization of the polarizer constituting the polarizing plate in a high temperature and high humidity environment It is preferable from the viewpoint of suppressing the decrease.
  • the production of the polarizing plate protective film according to the present invention includes the step of preparing a dope by dissolving the copolymer (A) according to the present invention, other resins and additives in a solvent, and filtering the prepared dope.
  • the film is cast on a belt-shaped or drum-shaped metal support to form a web, the formed web is peeled from the metal support to form a film, the film is stretched and dried, and the film is dried. After the film is cooled, it is performed by each process such as a process of winding in a roll.
  • the dissolution step is a dissolution pot in which the copolymer (A) and other additives according to the present invention are stored in an organic solvent mainly composed of a good solvent for the copolymer (A).
  • the dope which is the main solution is prepared by mixing, stirring and dissolving to prepare the dope, or mixing the resin solution containing the copolymer (A) with a solution in which other additives are dissolved in a solvent. It is a process to do.
  • the organic solvent useful for preparing the dope is limited as long as it dissolves the copolymer (A) and other additives at the same time. Can be used.
  • methylene chloride as a non-chlorinated organic solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro- 2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, nitroethane, etc.
  • methylene chloride, methyl acetate, ethyl acetate, and acetone can be preferably used as the main solvent.
  • the dope preferably contains a linear or branched aliphatic alcohol having 1 to 4 carbon atoms in the range of 1 to 40% by mass. If the proportion of alcohol in the dope is 40% by mass or less, the web will gel, and peeling from the metal support will be easy, and if the proportion of alcohol is 1% by mass or more, the non-chlorine organic solvent There is also a role of promoting dissolution of the copolymer (A) according to the present invention and other additives in the system.
  • a dope having an alcohol concentration in the range of 0.5 to 15.0 mass% is formed from the viewpoint of improving the flatness of the obtained polarizing plate protective film.
  • a filming method can be applied.
  • the concentration of the copolymer (A) and other additives according to the present invention in a concentration of 15 to 45 masses in a solvent containing methylene chloride and a linear or branched aliphatic alcohol having 1 to 4 carbon atoms. It is preferable that it is the dope composition melt
  • linear or branched aliphatic alcohol having 1 to 4 carbon atoms examples include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol. .
  • methanol and ethanol are preferable because they contribute to the stability of the dope, have a relatively low boiling point and good drying properties.
  • a method carried out at normal pressure a method carried out below the boiling point of the main solvent, a method carried out under pressure above the boiling point of the main solvent, JP-A-9 -95544, JP-A-9-95557, JP-A-9-95538, etc., a method of cooling and dissolving, and JP-A-11-21379, a method of performing at high pressure
  • Various dissolution methods such as, for example, can be used, but a method of pressurizing at a temperature equal to or higher than the boiling point of the main solvent is preferred.
  • the concentration of the copolymer (A) according to the present invention in the dope is preferably in the range of 10 to 40% by mass.
  • Various additives are added to the dope during or after dissolution of the copolymer (A) according to the present invention to dissolve and disperse it, and then filtered through a filter medium, defoamed, and sent to the next step with a liquid feed pump.
  • the filtration of the dope it is preferable to filter the dope with, for example, a filter medium having a 90% collection particle diameter of 10 to 100 times the average particle diameter of the fine particles with a main filter equipped with a leaf disk filter.
  • the filter medium used for filtration preferably has a low absolute filtration accuracy.
  • the absolute filtration accuracy is too small, the filter medium is likely to be clogged, and the filter medium must be frequently replaced. There is a problem of lowering productivity.
  • the filter medium used for the dope preferably has an absolute filtration accuracy of 0.008 mm or less, more preferably in the range of 0.001 to 0.008 mm, and more preferably in the range of 0.003 to 0.006 mm.
  • the filter medium is more preferable.
  • the filter medium is made of plastic fibers such as polypropylene and Teflon (registered trademark), and is made of metal such as stainless steel fibers that do not lose fibers.
  • the filter medium is preferable.
  • the dope flow rate during filtration is in the range of 10 to 80 kg / (h ⁇ m 2 ), and preferably in the range of 20 to 60 kg / (h ⁇ m 2 ).
  • the dope flow rate during filtration is 10 kg / (h ⁇ m 2 ) or more, the filtration efficiency is excellent in production suitability, and the dope flow rate during filtration is 80 kg / (h ⁇ m 2).
  • the pressure applied to the filter medium is appropriate, and the filter medium is not damaged, which is preferable.
  • the filtration pressure is preferably 3500 kPa or less, more preferably 3000 kPa or less, and even more preferably 2500 kPa or less.
  • the filtration pressure can be controlled by appropriately selecting the filtration flow rate and the filtration area.
  • FIG. 3 is a schematic diagram showing an example of a flow of a solution casting film forming step applicable to the production of the polarizing plate protective film according to the present invention.
  • the dope prepared in the charging tank 41 is fed to the stock tank 42 after removing large aggregates with a filter 44. Thereafter, the dope is fed from the stock kettle 42 to the main dope dissolving kettle 1 and various additive solutions are added to prepare the main dope.
  • the main dope is filtered by the main filter 3, and a matting agent dispersion liquid, an ultraviolet absorbent additive liquid and the like are added in-line through the conduit 16 to the main dope.
  • the main dope may contain about 10 to 50% by weight of recycled material.
  • the return material is, for example, a product obtained by finely pulverizing the polarizing plate protective film according to the present invention.
  • the raw material of the polarizing plate protective film exceeding the specified value is used.
  • the raw material of the resin used for the dope preparation those obtained by pelletizing the copolymer (A) according to the present invention and other additives in advance can be preferably used.
  • the metal support 31 in the casting (casting) step preferably has a mirror-finished surface, and the metal support 31 is preferably a stainless steel belt or a drum whose surface is plated with a casting.
  • the cast width can be in the range of 1 to 4 m, preferably in the range of 1.5 to 3 m, more preferably in the range of 2 to 2.8 m.
  • the surface temperature of the metal support 31 in the casting step is set in the range of ⁇ 50 ° C. to the temperature at which the solvent boils and does not foam, more preferably in the range of ⁇ 30 to 100 ° C. A higher temperature is preferable because the web can be dried faster, but if the temperature is too high, the web may foam or the flatness may deteriorate.
  • a preferable surface temperature of the metal support 31 is appropriately determined within a temperature range of 0 to 100 ° C., and more preferably within a range of 5 to 30 ° C.
  • the method for controlling the temperature of the metal support is not particularly limited, and there are a method of blowing warm air or cold air, and a method of bringing hot water into contact with the back side of the metal support. It is preferable to use warm water from the viewpoint that heat can be efficiently transferred and the time until the temperature of the metal support becomes constant can be shortened.
  • the pressurizing die 30 having a structure that can adjust the shape of the slit portion of the base portion and easily make the film thickness uniform is preferable.
  • the pressure die 30 includes a coat hanger die and a T die, and any of them is preferably used. In order to increase the deposition rate, a method may be used in which two or more pressure dies 30 are provided on the metal support 31 in the transport direction and the dope amount is divided and stacked.
  • Solvent evaporation step A web (hereinafter, the dope is cast on the casting metal support 31 and the formed dope film is referred to as a web) is heated on the casting metal support 31; This is a step of evaporating the solvent.
  • the method of transferring heat from the back side with a liquid is preferable from the viewpoint of good drying efficiency. It is also preferable to combine the above methods.
  • the web on the metal support 31 after casting is preferably dried on the metal support 31 in an atmosphere of 40 to 100 ° C. In order to maintain an atmosphere of 40 to 100 ° C., a method of applying hot air of this temperature to the upper surface of the web or heating by a heating means using radiant heat such as infrared rays is preferable.
  • Peeling step This is a step of peeling the web that has been in a film state due to evaporation of the solvent on the metal support 31 at the peeling position 33 shown in FIG.
  • the peeled web is made into a film and then sent to the subsequent drying and stretching steps.
  • the amount of residual solvent at the time of peeling on the metal support 31 at the time of peeling is the amount of residual solvent represented by the following formula (Z) depending on the strength of drying conditions, the length of the metal support, and the like. (%) Is preferably peeled in the range of 50 to 120% by mass. When peeling under conditions with more residual solvent, since the web is too soft, the flatness at the time of peeling is impaired, and slippage and vertical lines due to peeling tension are likely to occur, so the amount of residual solvent at the time of peeling (%) Is determined by a balance between economic speed and quality.
  • the residual solvent amount (%) of the web is defined by the following formula (Z).
  • Residual solvent amount (%) [(mass before web heat treatment ⁇ mass after web heat treatment) / (mass after web heat treatment)] ⁇ 100 Note that the heat treatment at the time of measuring the residual solvent amount is a heat treatment at 115 ° C. for 1 hour.
  • the peeling tension when peeling the metal support from the film is usually preferably in the range of 196 to 245 N / m. However, if wrinkles are likely to occur during peeling, the tension is 190 N / m or less. Can also be peeled off.
  • the temperature at the peeling position 33 on the metal support 31 is preferably in the range of ⁇ 50 to 40 ° C., more preferably in the range of 10 to 40 ° C., and in the range of 15 to 30 ° C. Is most preferable.
  • the drying step can be performed by dividing it into a preliminary drying step and a main drying step.
  • the web obtained by peeling from the metal support is dried.
  • the web may be dried while being conveyed by a large number of rollers arranged above and below, or may be dried while being conveyed while fixing both ends of the web with clips like a tenter dryer. .
  • the means for drying the web is not particularly limited, and can be performed by general hot air, infrared rays, a heating roller, microwave, or the like, but it is preferably performed by hot air from the viewpoint of simplicity.
  • the drying temperature in the web drying step is preferably a glass transition temperature (Tg) of the polarizing plate protective film of ⁇ 5 ° C. or lower, and it is effective to perform a heat treatment within a range of 5 to 20 minutes at a temperature of 100 ° C. or higher. Is. Drying is performed at a drying temperature in the range of 100 to 200 ° C, more preferably in the range of 110 to 160 ° C.
  • Tg glass transition temperature
  • the polarizing plate protective film according to the present invention can control the orientation of molecules in the film by being subjected to a stretching treatment, and can improve planarity and impart toughness.
  • the stretching operation may be performed in multiple stages. Moreover, when performing biaxial stretching, you may perform simultaneous biaxial stretching and the method of extending
  • stepwise means that, for example, stretching can be performed independently in the longitudinal direction and the width direction with different stretching directions, and stretching in the same direction is divided into multiple stages and different directions. It is also possible to add this stretching to any stage.
  • simultaneous biaxial stretching includes stretching in one direction and contracting the other while relaxing the tension.
  • the amount of residual solvent in the film at the start of stretching is preferably in the range of 2 to 10% by mass.
  • the amount of residual solvent in the film at the time of stretching is 2% by mass or more, the deviation of the film thickness is small, which is preferable from the viewpoint of flatness, and if it is 10% by mass or less, the surface unevenness is reduced and the flatness is reduced. Improved and preferable.
  • the polarizing plate protective film according to the present invention has (Tg + 15) when the glass transition temperature of the film is defined as Tg in the MD direction or TD direction, preferably in the TD direction so that the film thickness after stretching is in a desired range. ) To (Tg + 50) ° C. is preferably stretched. When stretched in the above temperature range, the stretching stress can be reduced, and the haze of the film can be kept low. Moreover, generation
  • the stretching temperature is preferably in the range of (Tg + 20) to (Tg + 40) ° C.
  • the polarizing plate protective film according to the present invention preferably stretches the web within a range of 1.01 to 10 times at least in the MD direction or TD direction. That is, the stretching range is preferably in the range of 1.1 to 10 times the original width, and more preferably in the range of 1.2 to 8.0 times. If it is in the said range, a film will become toughness, a film can be thinned, and the flatness of a film can be improved.
  • peeling is preferably performed at a peeling tension of 130 N / m or more, particularly preferably 150 to 170 N / m. Since the web after peeling is in a high residual solvent state, stretching in the MD direction can be performed by maintaining the same tension as the peeling tension. As the web dries and the residual solvent amount decreases, the stretch ratio in the MD direction decreases.
  • the stretching in the MD direction can be performed using a roller stretching machine utilizing a difference in the peripheral speed of the roller, and the stretching ratio can be calculated from the rotational speed of the belt-shaped metal support and the operating speed of the roller stretching machine.
  • a drying method (referred to as a tenter method), among them, a clip tenter method using a clip and a pin tenter method using a pin are preferably used.
  • stretching in the TD direction stretching in the width direction of the film at a stretching speed of 250 to 500% / min is preferable from the viewpoint of improving the flatness of the film.
  • the stretching speed is 250% / min or more, the planarity is improved and the film can be processed at a high speed, which is preferable from the viewpoint of productivity, and if it is 500% / min or less, the film is broken. Therefore, the stretching process can be stably performed, which is preferable.
  • More preferable stretching speed is in the range of 300 to 400% / min.
  • the stretching speed is defined by the following formula (E).
  • the in-plane retardation value Ro and the retardation value Rt in the thickness direction of the polarizing plate protective film according to the present invention are measured using an automatic birefringence meter Axoscan (Axo Scan Mueller Matrix Polarimeter: manufactured by Axometrics). 23 ° C., under an environment of 55% RH, subjected to three-dimensional refractive index measured at a wavelength of 590 nm, the refractive index will be described later resulting n x, n y, it can be calculated from n z.
  • the polarizing plate protective film according to the present invention has a retardation value (Rt) defined by the following formula (ii) within a range of the retardation value (Ro) defined by the following formula (i) of 0 to 70 nm.
  • the range of ⁇ 50 to 10 nm is preferable particularly when the polarizing plate protective film does not require retardation.
  • it can be set as desired in-plane retardation value Ro and retardation value Rt by extending
  • n x represents a refractive index in the direction x in which the refractive index is maximized in the plane direction of the film.
  • n y in-plane direction of the film, the refractive index in the direction y perpendicular to the direction x.
  • nz represents the refractive index in the thickness direction z of the film.
  • d represents the thickness (nm) of the film.
  • the residual solvent is removed from the web that has been subjected to the stretching treatment and dried.
  • the web may be dried while being conveyed by a large number of rollers arranged above and below, or may be dried while being conveyed while fixing both ends of the web with clips like a tenter dryer. .
  • the amount of residual solvent in the web is preferably 2% by mass or less.
  • the means for drying the web is not particularly limited, and can be performed by general hot air, infrared rays, a heating roller, microwave, or the like, but it is preferably performed by hot air from the viewpoint of simplicity.
  • the drying temperature in the main drying step is preferably a glass transition temperature (Tg) of the polarizing plate protective film of ⁇ 5 ° C. or lower, and it is effective to perform a heat treatment within a range of 10 to 60 minutes at a temperature of 100 ° C. or higher. It is. Drying is performed at a drying temperature in the range of 100 to 200 ° C, more preferably in the range of 110 to 160 ° C.
  • Tg glass transition temperature
  • ⁇ Knurling> After performing a predetermined heat treatment or cooling treatment, it is preferable to provide a slitter and take off the end portion before winding to obtain a good winding shape. Furthermore, it is preferable to apply a knurling process to both ends of the width.
  • a concavo-convex structure can be formed at both ends of the polarizing plate protective film by pressing a heated embossing roller against the formed polarizing plate protective film. Fine irregularities (embossing) are formed at both ends of the embossing roller, and by pressing this, irregularities can be formed at both ends of the polarizing plate protective film, and the ends can be made bulky.
  • the height of the knurling at both width ends is preferably in the range of 4 to 20 ⁇ m, and the width is preferably in the range of 5 to 20 mm.
  • the knurling process is preferably provided after the drying process and before winding in the film forming process of the polarizing plate protective film.
  • Winding step This is a step of winding as a film after the amount of residual solvent in the web is 2% by mass or less. By making the residual solvent amount 0.4% by mass or less, good dimensional stability is obtained. A film can be obtained.
  • a winding method As a winding method, a commonly used one may be used, and there are a constant torque method, a constant tension method, a taper tension method, a program tension control method with a constant internal stress, etc., and these may be used properly.
  • the polarizing plate protective film according to the present invention can be formed by a melt casting method in addition to the solution casting method described above.
  • the melt casting method the film composition containing the copolymer (A) according to the present invention and other additives is heated and melted to a temperature showing fluidity, and then the fluid melt is cast. This is a method for forming a polarizing plate protective film.
  • the melt extrusion method is preferable from the viewpoint of mechanical strength and surface accuracy.
  • the plurality of raw materials used in the melt extrusion method that is, the copolymer (A) according to the present invention and other additives are preferably kneaded in advance and pelletized.
  • Pelletization can be performed by a known method.
  • the copolymer (A) according to the present invention and other additives are supplied to an extruder by a feeder and mixed using a uniaxial or biaxial extruder. It can be pelletized by smelting, extruding into a strand form from a die, water cooling or air cooling, and then cutting.
  • Additives may be mixed before being supplied to the extruder, or may be supplied by individual feeders.
  • a small group of additives such as particles and antioxidants are preferably mixed in advance in order to mix uniformly.
  • the extruder is preferably processed at as low a temperature as possible within a range that can be pelletized so that the shearing force is suppressed and deterioration of the copolymer (A) or the like (for example, molecular weight reduction, coloring, gel formation, etc.) does not occur.
  • the copolymer (A) or the like for example, molecular weight reduction, coloring, gel formation, etc.
  • Film formation is performed using the pellets obtained as described above.
  • the raw material powder can be directly fed to the extruder with a feeder to form a film without pelletization.
  • the melting temperature when extruding the above pellets using a single-screw or twin-screw type extruder is in the range of 200 to 300 ° C.
  • a polarizing plate protective film can be formed by casting into a film, nip the film with a cooling roller and an elastic touch roller, and solidifying the film on the cooling roller.
  • the copolymer (A) or the like is supplied from the supply hopper to the extruder, it is preferable to prevent oxidative decomposition or the like of the material under vacuum or reduced pressure or in an inert gas atmosphere.
  • the extrusion flow rate is preferably stabilized by introducing a gear pump or the like.
  • a stainless fiber sintered filter is preferably used as a filter used for removing foreign substances.
  • the stainless steel fiber sintered filter is an integrated filter that creates an intricately intertwined state of the stainless steel fiber body and then compresses and sinters the contact area. The density is adjusted by the thickness and amount of compression of the stainless steel fiber. In addition, the filtration accuracy can be controlled.
  • Additives such as antioxidants and matting agent particles may be previously mixed with the copolymer (A) or the like, or may be added and kneaded in the middle of the extruder. In order to add uniformly, it is preferable to use a mixing apparatus such as a static mixer.
  • the polarizing plate protective film temperature on the elastic touch roller side when the polarizing plate protective film is nipped between the cooling roller and the elastic touch roller is preferably in the range of Tg to (Tg + 110 ° C.) of the film.
  • the elastic touch roller having an elastic body on the surface is also referred to as a pinching rotary body, and is not particularly limited, and a commercially available roller can be appropriately selected and used.
  • the film obtained as described above is stretched by the same stretching operation as in the solution casting method after passing through the step of contacting the cooling roller.
  • the stretching method a known roller stretching machine or tenter can be preferably used.
  • the stretching temperature is usually preferably in the temperature range of Tg to (Tg + 60) ° C. of the resin constituting the film.
  • the ends Before winding, the ends may be slit and trimmed to the product width, and the knurling process (embossing process) may be applied to both ends to prevent sticking and scratching during winding.
  • the knurling method can be performed by heating or pressurizing using a metal roller having an uneven pattern at the end or a metal ring having an uneven pattern on the side as described above.
  • the polarizing plate protective film has deform
  • the haze is preferably 1.0% or less, and more preferably 0.5% or less.
  • the haze is measured with a haze meter (turbidity meter) (model: NDH 2000, manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS K-7136.
  • the total light transmittance of the polarizing plate protective film according to the present invention is preferably 90% or more, and more preferably 93% or more.
  • the total light transmittance can be measured in accordance with JIS K 7375: 2008 “Plastics—Determination of total light transmittance and total light reflectance”.
  • the equilibrium water content at 25 ° C. and relative humidity 55% is preferably 3.0% by mass or less, and more preferably 2.0% by mass or less.
  • the equilibrium moisture content is preferable to easily cope with a change in humidity and to hardly change the optical characteristics and dimensions.
  • the polarizing plate protective film according to the present invention preferably has a long length, and specifically, preferably has a length of about 100 to 10,000 m, and is wound in a state of being laminated in a roll shape. Further, the width of the polarizing plate protective film according to the present invention is preferably 1 m or more, more preferably 1.4 m or more, and particularly preferably in the range of 1.4 to 4 m.
  • the film thickness is in the range of 20-60 ⁇ m. When the film thickness is 20 ⁇ m or more, a certain level of film strength and retardation can be expressed. When the film thickness is 60 ⁇ m or less, the film has a desired retardation, and can be applied to thin the polarizing plate and the display device, and the bend unevenness and the thin film can be balanced.
  • the moisture permeability at 40 ° C. and 90% RH is preferably 300 g / m 2 ⁇ day or less, more preferably 250 g / m 2 ⁇ day or less.
  • a range of 200 g / m 2 ⁇ day is particularly preferable for suppressing bend unevenness. This is for suppressing a change in the size of the polarizer due to the transmitted water in a high temperature and high humidity environment.
  • the moisture permeability is measured under the conditions of 40 ° C. and 90% RH in accordance with the method described in JIS Z 0208: 1976 “Moisture permeability test method for moisture-proof packaging material (cup method)”.
  • the moisture permeability of the polarizing plate protective film can be adjusted by, for example, the content of an aromatic vinyl monomer, for example, a styrene monomer, in the constituent unit of the copolymer (A) according to the present invention.
  • an aromatic vinyl monomer for example, a styrene monomer
  • the content ratio of the structural unit derived from the aromatic vinyl monomer in the polymer (A) according to the present invention may be set large.
  • the tear strength of the polarizing plate protective film according to the present invention at 23 ° C. and 55% RH is preferably 15 mN or more, more preferably 20 mN or more, and further preferably 30 mN or more.
  • the upper limit of the tear strength is about 50 mN.
  • the tear strength of the polarizing plate protective film can be measured by the following method.
  • the polarizing plate protective film is cut into a size of width 50 mm ⁇ length 64 mm to prepare a sample film.
  • the sample film is conditioned for 24 hours in an environment of 23 ° C. and 55% RH, and the Elmendorf tear strength is measured in accordance with ISO 6383-2: 1983. Specifically, the Elmendorf tear strength can be measured using, for example, a light load tear tester manufactured by Toyo Seiki Co., Ltd. The tear strength was determined for each of the cases of tearing in the film length direction (MD direction) and film width direction (TD direction) in an environment of 23 ° C. and 55% RH. Calculated as a value.
  • the tear strength of the polarizing plate protective film can be adjusted by, for example, the molecular weight of the copolymer (A) or other resin.
  • the molecular weight of the copolymer (A) or other resin may be increased.
  • a functional layer having various functions can be provided on at least one surface of the film.
  • the functional layer include a hard coat layer, an antistatic layer, a back coat layer, an antireflection layer, a slippery layer, an adhesive layer, an antiglare layer, and a gas barrier layer.
  • the polarizing plate protective film according to the present invention has high toughness and is less likely to cause thermal shrinkage unevenness, and thus has excellent resistance to heat treatment when a functional layer is provided.
  • the hard coat layer can be formed of a cured product of an actinic radiation curable compound.
  • an actinic radiation curable compound a component containing a monomer having an ethylenically unsaturated double bond can be preferably used.
  • the actinic radiation curable compound include an ultraviolet curable compound and an electron beam curable compound, but an ultraviolet curable compound that is cured by ultraviolet irradiation is superior in mechanical film strength (abrasion resistance, pencil hardness). preferable.
  • an ultraviolet curable urethane acrylate resin for example, an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, or an ultraviolet curable epoxy resin is preferable. Used. Of these, UV curable acrylate resins are preferred.
  • the hard coat layer is formed by applying a hard coat layer forming coating solution containing an actinic radiation curable compound and a photopolymerization initiator on the polarizing plate protective film according to the present invention, and then curing it by irradiation with actinic radiation. Can be formed.
  • the photopolymerization initiator examples include acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, ⁇ -amyloxime ester, thioxanthone, and derivatives thereof, but are not particularly limited thereto.
  • the hard coat layer forming coating solution preferably further contains inorganic fine particles or organic fine particles as necessary.
  • inorganic fine particles include silicon oxide, titanium oxide, aluminum oxide, tin oxide, indium oxide, ITO, zinc oxide, zirconium oxide, magnesium oxide, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, and hydration.
  • Calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate are included, and preferably silicon oxide, titanium oxide, aluminum oxide, zirconium oxide, magnesium oxide and the like are used.
  • organic fine particles examples include polymethacrylic acid methyl acrylate resin powder, acrylic styrene resin powder, polymethyl methacrylate resin powder, and silicone resin powder.
  • the average particle diameter of the fine particles is not particularly limited, but is preferably in the range of 0.01 to 5 ⁇ m in consideration of forming an antiglare layer and the like in addition to the hard coat layer. More preferably, it is in the range of 01 to 1.0 ⁇ m. Further, two or more kinds of fine particles having different particle diameters may be mixed and used.
  • the average particle diameter of the fine particles can be measured by, for example, a laser diffraction particle size distribution measuring device.
  • the content ratio of the fine particles is preferably blended so as to be in the range of 10 to 400 parts by mass, more preferably in the range of 50 to 200 parts by mass with respect to 100 parts by mass of the ultraviolet curable compound.
  • These hard coat layers for example, using a known wet coating method such as a gravure coater, a dip coater, a reverse coater, a wire bar coater, a die coater, an ink jet method, a coating composition for forming a hard coat layer is applied, It can be formed by heating and drying after coating and applying a curing treatment by ultraviolet irradiation.
  • a known wet coating method such as a gravure coater, a dip coater, a reverse coater, a wire bar coater, a die coater, an ink jet method
  • a coating composition for forming a hard coat layer is applied, It can be formed by heating and drying after coating and applying a curing treatment by ultraviolet irradiation.
  • the film thickness after drying of the hard coat layer is in the range of 0.1 to 30 ⁇ m, preferably 1 to 20 ⁇ m, particularly preferably 6 to 15 ⁇ m, as the average film thickness.
  • any light source that emits ultraviolet rays as an active energy ray can be used without limitation.
  • a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used.
  • Irradiation conditions vary depending on each lamp, but the irradiation amount of active energy rays is usually within a range of 5 to 500 mJ / cm 2 , preferably within a range of 5 to 200 mJ / cm 2 .
  • an antireflection layer may be further provided on the upper surface of the hard coat layer.
  • the polarizing plate protective film according to the present invention can be used as an antireflection film having an external light antireflection function.
  • the antireflection layer is preferably laminated in consideration of the refractive index, the film thickness, the number of layers, the layer order, and the like so that the reflectance is reduced by optical interference.
  • the antireflection layer is composed of a low refractive index layer having a refractive index lower than that of the support (the above-mentioned optical film), or a combination of a high refractive index layer having a refractive index higher than that of the support and a low refractive index layer. Is preferred.
  • an antireflection layer composed of three or more refractive index layers, and three layers having different refractive indexes from the support side are divided into medium refractive index layers (high refractive index layers having a higher refractive index than the support).
  • medium refractive index layers high refractive index layers having a higher refractive index than the support.
  • the layer configuration of the antireflection film using the polarizing plate protective film according to the present invention the following configurations are conceivable, but are not limited thereto.
  • Polarizing plate protective film / hard coat layer / low refractive index layer Polarizing plate protective film / hard coat layer / medium refractive index layer / low refractive index layer
  • the refractive index of the silica-based fine particles is preferably lower than the refractive index of the polarizing plate protective film as a support, and is preferably in the range of 1.30 to 1.45 at 23 ° C. and a wavelength of 550 nm.
  • the silica-based fine particles preferably include at least one kind of particles having an outer shell layer and porous or hollow inside.
  • the particles having the outer shell layer and having a porous or hollow interior are preferably hollow silica-based fine particles.
  • the film thickness of the low refractive index layer is preferably 5 nm to 0.5 ⁇ m, more preferably 10 nm to 0.3 ⁇ m, and most preferably 30 nm to 0.2 ⁇ m.
  • the low refractive index layer can be formed by applying and drying a coating solution for forming a low refractive index layer, followed by curing.
  • the coating solution for forming a low refractive index layer contains the silica-based fine particles, and may further contain an organosilicon compound represented by the following formula (S), a hydrolyzate thereof, or a polycondensate thereof.
  • R represents an alkyl group having 1 to 4 carbon atoms.
  • tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane and the like are preferably used.
  • the coating solution for the low refractive index layer may further contain a solvent, a silane coupling agent, a curing agent, a surfactant and the like as necessary.
  • the polarizing plate protective film which concerns on this invention is the structure currently bonded on the one surface of the polarizer at least using the active energy ray hardening-type adhesive agent.
  • a cellulose ester phase difference film is similarly applied to the surface of the polarizer opposite to the surface on which the polarizing plate protective film is bonded, using an active energy ray-curable adhesive. It is preferable from the viewpoint of handleability, reworkability, and optical characteristics, and also preferable from the viewpoint of simplification of the bonding process.
  • the outer films T1 and T4 are films with low moisture permeability and the inner films T2 and T3 (retardation film) are cellulose ester films, It is preferable from the viewpoint that the influence of moisture can be reduced and internal moisture can be easily released, and the durability of the polarizing plate against humidity fluctuations is improved overall.
  • the polarizing plate of the present invention has a structure in which the polarizer is sandwiched between the polarizing plate protective film according to the present invention and the cellulose ester phase difference film, which improves durability, suppresses bend unevenness, and is excellent. From the viewpoint of imparting high visibility to the liquid crystal display device, this is a preferred embodiment.
  • the polarizing plate protective film on the viewing side is an antiglare layer or a clear hard coat layer, an antireflection layer, an antistatic layer, an antifouling layer, etc. It is preferable to provide a functional layer.
  • the polarizing plate protective film according to the present invention has a particularly high effect of suppressing variation in heat shrinkage after coating. Therefore, even if the functional layer is formed by coating, and then heated and dried to perform ultraviolet irradiation, Shrinkage is small, and generation of wrinkles in the film and cracks in the functional layer can be suppressed.
  • the polarizer which is the main component of the polarizing plate of the present invention, is an element that passes only light having a plane of polarization in a certain direction, and a typical known polarizer is a polyvinyl alcohol polarizing film.
  • the polyvinyl alcohol polarizing film includes those obtained by dyeing iodine on a polyvinyl alcohol film and those obtained by dyeing a dichroic dye.
  • the polarizer it is possible to use a polarizer obtained by forming a polyvinyl alcohol aqueous solution into a film and dyeing it by uniaxial stretching or dyeing and then uniaxially stretching, and then preferably performing a durability treatment with a boron compound.
  • the film thickness of the polarizer is in the range of 5 to 15 ⁇ m, and particularly preferably in the range of 5 to 10 ⁇ m.
  • the ethylene unit content described in JP 2003-248123 A, JP 2003-342322 A, etc. is in the range of 1 to 4 mol%
  • the polymerization degree is in the range of 2000 to 4000
  • saponification Ethylene-modified polyvinyl alcohol having a degree in the range of 99.0 to 99.99 mol% is also preferably used.
  • an ethylene-modified polyvinyl alcohol film having a hot water cutting temperature in the range of 66 to 73 ° C. is preferably used.
  • a polarizer using this ethylene-modified polyvinyl alcohol film is excellent in polarization performance and durability, and has little color unevenness, and is particularly preferably used for a large liquid crystal display device.
  • the polarizing plate of the present invention is preferably a thin film, and the thickness of the polarizer is particularly preferably in the range of 2 to 15 ⁇ m from the viewpoint of achieving both the strength of the polarizing plate and the reduction of the thickness.
  • a thin film polarizer for example, a method described in Japanese Patent Application Laid-Open No. 2011-10061, Japanese Patent No. 4691205, Japanese Patent No. 4751481, Japanese Patent No. 4804589, and the like can be used. Is preferably produced.
  • the polarizing plate of the present invention can be produced by a general method.
  • the surface of the polarizing plate protective film according to the present invention to be bonded to the polarizer is subjected to surface treatment such as corona treatment, plasma treatment, or excimer light treatment, and is then immersed in an iodine solution and drawn at least one of the polarizers. Attached to the surface using an active energy ray-curable adhesive.
  • the retardation film and the polarizer which will be described below, are similarly bonded with an active energy ray-curable adhesive.
  • the retardation film is a cellulose ester film
  • the surface may be saponified.
  • the direction of bonding with the polarizer is preferably bonded so that, for example, the absorption axis of the polarizer and the slow axis of the polarizing plate protective film are orthogonal to each other.
  • Another polarizing plate protective film can be bonded to the other surface of the polarizer.
  • a conventional polarizing plate protective film commercially available cellulose ester films (for example, Konica Minoltak KC8UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC4FR, KC4KR, KC4DR, KC4SR, KC8UY, KC6UY, KC, KC8UE, KC8UY-HA, KC8UX-RHA, KC8UXW-RHA-C, KC8UXW-RHA-NC, KC4UXW-RHA-NC, and the like, manufactured by Konica Minolta Co., Ltd.) are preferably used.
  • Phase difference film On one surface of the polarizer, it is preferable to dispose retardation films as T2 and T3 in order to improve visibility such as widening the viewing angle and improving contrast provided in the VA liquid crystal auxiliary display device.
  • the retardation film is not particularly limited, but is preferably a cellulose ester film, for example.
  • cellulose esters constituting the cellulose ester film include cellulose triacetate, cellulose diacetate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate benzoate, cellulose acetate propionate benzoate, cellulose propionate, and cellulose butyrate.
  • the cellulose ester preferably has a total acyl group substitution degree in the range of 1.5 to 2.5, and more preferably satisfies the following formulas (a) and (b).
  • Formula (a) 2.0 ⁇ X + Y ⁇ 2.5
  • Formula (b) 0 ⁇ Y ⁇ 1.5
  • X represents the degree of substitution of the acetyl group
  • Y represents the degree of substitution of the propionyl group, butyryl group, or a mixture thereof.
  • the weight average molecular weight (Mw) of the cellulose ester is preferably 75,000 or more, more preferably 100,000 to 1,000,000, from the viewpoint of film strength and appropriate viscosity during film formation. It is particularly preferable that it is ⁇ 500,000.
  • the cellulose ester film may be a single layer film or a laminated film.
  • the cellulose ester film is a laminated film, it is a laminate of a core layer mainly composed of a cellulose ester having a low degree of substitution and a skin layer mainly composed of a cellulose ester having a high degree of substitution disposed on both sides thereof. It is preferable.
  • the cellulose ester having a low degree of substitution preferably satisfies the above formulas (a) and (b), and the cellulose ester having a high degree of substitution preferably has a total acyl group substitution degree of more than 2.5, and preferably 2.7. More preferably, it is within the range of -2.98, and it is particularly preferable that all the acyl groups contained in the cellulose ester are acetyl groups.
  • the retardation of the retardation film can be set according to the type of liquid crystal cell to be combined.
  • the retardation value Ro in the in-plane direction measured at a wavelength of 590 nm under an environment of 23 ° C. and 55% RH of the retardation film is preferably in the range of 30 to 150 nm, and the retardation in the thickness direction
  • the value Rt is preferably in the range of 70 to 300 nm.
  • a retardation film having a retardation value in the above range can be preferably used as a retardation film such as a VA liquid crystal cell.
  • Ro and Rt are defined as described above.
  • the thickness of the retardation film is not particularly limited, but is preferably in the range of 10 to 250 ⁇ m, more preferably in the range of 10 to 100 ⁇ m, and particularly preferably in the range of 30 to 60 ⁇ m. preferable.
  • the polarizing plate protective film according to the present invention described above and at least one surface side of the polarizer are preferably bonded with an active energy ray-curable adhesive.
  • the retardation film and the polarizer are similarly bonded with an active energy ray-curable adhesive.
  • they are bonded by the same type of active energy ray-curable adhesive.
  • the productivity is high.
  • the deformation of the polarizing plate can be suppressed, and excellent flatness can be obtained.
  • the active energy ray-curable adhesive applicable to the production of the polarizing plate of the present invention includes a photo radical polymerization composition utilizing photo radical polymerization, a photo cation polymerization composition utilizing photo cation polymerization, and a photo radical.
  • polymerization and photocationic polymerization together can be mentioned.
  • the photo-radical polymerization composition examples include a specific ratio of a radical polymerizable compound containing a polar group such as a hydroxy group and a carboxy group described in JP-A-2008-009329 and a radical polymerizable compound not containing a polar group. And the like are known.
  • the radical polymerizable compound is preferably a compound having an ethylenically unsaturated bond capable of radical polymerization.
  • the compound having an ethylenically unsaturated bond capable of radical polymerization include a compound having a (meth) acryloyl group.
  • the compound having a (meth) acryloyl group examples include an N-substituted (meth) acrylamide compound and a (meth) acrylate compound.
  • (Meth) acrylamide means acrylamide or methacrylamide.
  • cationic photopolymerization type composition as described in JP 2011-028234 A, ( ⁇ ) cationic polymerizable compound, ( ⁇ ) photo cationic polymerization initiator, ( ⁇ ) wavelength longer than 380 nm
  • active energy ray-curable adhesive composition containing each of the components of a photosensitizer exhibiting maximum absorption in the light of ( ⁇ ) and a naphthalene-based photosensitization aid.
  • active energy ray-curable adhesives may be used.
  • an ultraviolet curable adhesive as described in the above publication is preferably used.
  • Pretreatment process In the pretreatment step, an easy adhesion treatment is performed on the surface of the polarizing plate protective film adhered to the polarizer. As illustrated in FIG. 1, when bonding the respective polarizing plate protective film 102 and the retardation film 105 on both surfaces of the polarizer 104, through the active energy ray-curable adhesive 103A 1 and 103A 2 are respectively An easy adhesion treatment is performed on the adhesion surfaces of the polarizing plate protective film 102 and the retardation film 105.
  • the surface side of each film subjected to easy adhesion treatment is treated as a bonding surface with the polarizer 104.
  • the layer 103A 1 and bonding a surface, subjected to easy adhesion treatment include corona treatment, plasma treatment, and excimer light treatment.
  • the active energy ray-curable adhesive is applied to at least one surface side of the adhesive surfaces of the polarizer 104 and the polarizing plate protective film 102.
  • an active energy ray hardening-type adhesive directly on the surface of a polarizer or a polarizing plate protective film
  • various wet coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater can be applied.
  • the method of pressing with a roller etc. and spreading it uniformly can also be applied.
  • attachment process is given at the bonding process.
  • the bonding step for example, when the active energy ray-curable adhesive is applied to the surface of the polarizer 104 in the previous adhesive application step, the polarizing plate protective film 102 is superimposed thereon.
  • the polarizer 104 is superimposed thereon.
  • the polarizer 104 and the polarizing plate protective film 102 are overlapped with each other in that state.
  • the active energy ray-curable adhesive is bonded to both surfaces of the polarizer.
  • the polarizing plate protective film 102 and the retardation film 105 are superposed through the applied active energy ray-curable adhesive.
  • a polarizing plate protective film when superimposed on both sides, for example, one side of a polarizer, a polarizing plate protective film and a retardation film are provided on the polarizer side and the polarizing plate protective film side, and on both sides of the polarizer.
  • a roller or the like As the material of the roller, metal, rubber or the like can be used.
  • the rollers arranged on both sides may be made of the same material or different materials.
  • the applied active energy ray-curable adhesive is irradiated with active energy rays, and a cationic polymerizable compound (eg, epoxy compound or oxetane compound) or a radical polymerizable compound (eg, acrylate compound, acrylamide).
  • a cationic polymerizable compound eg, epoxy compound or oxetane compound
  • a radical polymerizable compound eg, acrylate compound, acrylamide
  • Examples of active energy rays that can be used for curing include visible light, ultraviolet rays, X-rays, and electron beams. However, since they are easy to handle and have a sufficient curing rate, And ultraviolet rays are preferably used.
  • a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used.
  • An ArF excimer laser, a KrF excimer laser, an excimer lamp, synchrotron radiation, or the like can also be used.
  • an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a xenon arc, and a metal halide lamp are preferably used.
  • the electron beam 50 to 1000 keV emitted from various electron beam accelerators such as Cockloft Walton type, Bande graph type, resonance transformation type, insulation core transformation type, linear type, dynamitron type, and high frequency type, preferably 100
  • An electron beam having an energy in the range of up to 300 keV can be mentioned.
  • the acceleration voltage is preferably in the range of 5 to 300 kV, more preferably in the range of 10 to 250 kV. If the acceleration voltage is 5 kV or more, the electron beam can reach the adhesive sufficiently to obtain desired curing conditions, and if the acceleration voltage is 300 kV or less, the irradiation energy and the penetration force may become excessively strong. Without damaging the transparent polarizing plate protective film and the polarizer.
  • the irradiation dose is in the range of 5 to 100 kGy, more preferably in the range of 10 to 75 kGy. If the irradiation dose is 5 kGy or more, the active energy ray-curable adhesive is sufficiently cured, and if it is 100 kGy or less, the polarizing plate protective film and the polarizer are not damaged, and a desired adhesive strength is obtained. Can do.
  • the dose of ultraviolet rays is preferably in accumulated light amount is within the range of 50 ⁇ 1500mJ / cm 2, and even more preferably in the range of 100 ⁇ 500mJ / cm 2.
  • the line speed depends on the curing time of the active energy ray-curable adhesive, but is preferably in the range of 1 to 500 m / min, more preferably 5 to 300 m / min, and further Preferably, it is within the range of 10 to 100 m / min.
  • the line speed is 1 m / min or more, appropriate productivity can be secured, damage to the transparent polarizing plate protective film can be suppressed, and a polarizing plate excellent in durability can be produced.
  • the line speed is 500 m / min or less, the resulting adhesive is sufficiently cured, and the desired adhesiveness can be obtained.
  • the thickness of the active energy ray-curable adhesive layer is not particularly limited, but is usually in the range of 0.01 to 10 ⁇ m, preferably 0.5 to 5 ⁇ m. Within range.
  • ⁇ Liquid crystal display device> In the liquid crystal display device of the present invention, at least the first polarizing plate A, the liquid crystal cell, and the second polarizing plate B are arranged in this order from the viewing surface side, and the first polarizing plate A from the viewing surface side. Is composed of a polarizing plate protective film T1, a polarizer and a retardation film T2, and a second polarizing plate B is composed of a retardation film T3, a polarizer and a polarizing plate protective film T4, and constitutes the polarizing plate of the present invention.
  • the polarizing plate protective film is a polarizing plate protective film T1 constituting the polarizing plate A or a polarizing plate protective film T4 constituting the polarizing plate B, and any of the polarizing plate protective film T1 and the polarizing plate protective film T4 Is preferably a polarizing plate protective film having a structure defined in the present invention.
  • the viewing side surface of the polarizing plate protective film T1 has a functional layer such as a hard coat layer, an antireflection layer, or an antiglare layer.
  • the polarizing plate protective film according to the present invention is excellent in water resistance, heat resistance, flatness and the like, the glass substrate constituting the liquid crystal cell is formed into a thin film by providing the liquid crystal display device with the polarizing plate of the present invention. As a result, it is possible to obtain a liquid crystal display device in which thinning is achieved.
  • glass substrate examples include soda lime glass, silicate glass, and the like, and preferably silicate glass, specifically, silica glass or borosilicate glass. More preferably.
  • the glass constituting the glass substrate is preferably a non-alkali glass that does not substantially contain an alkali component, specifically, a glass having an alkali component content of 1000 ppm or less.
  • the content of the alkali component in the glass substrate is preferably 500 ppm or less, and more preferably 300 ppm or less.
  • substitution of cations occurs on the film surface, and soda blowing phenomenon tends to occur. Thereby, the density of the film surface layer tends to be lowered, and the glass substrate is easily damaged.
  • the thickness of the glass substrate of the liquid crystal cell constituting the liquid crystal display device is preferably in the range of 0.4 to 0.6 mm. Such a thickness is preferable in that it can contribute to the formation of a thin liquid crystal display device.
  • the glass substrate can be formed by a known method such as a float method, a down draw method, an overflow down draw method or the like. Of these, the overflow downdraw method is preferred because the surface of the glass substrate does not come into contact with the molded member during molding and the surface of the resulting glass substrate is hardly damaged.
  • Such a glass substrate can also be obtained as a commercial product.
  • non-alkali glass AN100 (thickness 500 ⁇ m) manufactured by Asahi Glass Co., Ltd.
  • glass substrate EAGLE XG (r) Slim (thick manufactured by Corning) 300 ⁇ m, 400 ⁇ m, etc.
  • glass substrates (thickness 100 to 200 ⁇ m) manufactured by Nippon Electric Glass Co., Ltd.
  • the polarizing plate of the present invention By using the polarizing plate of the present invention, even if the screen using the thin film glass substrate for a liquid crystal cell is a large-screen liquid crystal display device of 30 type or more, display unevenness (bend unevenness) is suppressed and the front surface is suppressed. A liquid crystal display device having excellent visibility such as contrast can be obtained.
  • the mode (driving method) of the liquid crystal display device is not particularly limited, and liquid crystal display devices of various drive modes such as STN, TN, OCB, HAN, VA (MVA, PVA), IPS, OCB, and the like can be used.
  • a VA (MVA, PVA) type liquid crystal display device is preferable.
  • the direction of bonding of the polarizing plate in the VA mode liquid crystal display device can be performed with reference to JP-A-2005-234431.
  • a liquid crystal display device having excellent visibility such as unevenness of the liquid crystal display device can be obtained even for a liquid crystal display device with a large screen of 30 type or more. be able to.
  • Example 1 Synthesis of Copolymer (A) >> [Synthesis of Copolymer A1]
  • monomers 93.6 parts by mass (90 mol%) of styrene, 7.2 parts by mass (10 mol%) of acrylic acid, 29.4 parts by mass of ethylbenzene, and 3.3 parts by mass of 2-ethylhexanol are mixed.
  • 0.04 parts by mass of 2,2-bis (4,4-ditertiary butyl peroxide) propane was added to the liquid, and this polymerization liquid was added to a polymerization apparatus having a 5.0 L complete mixing reactor. Charged continuously at 1.67 L / hr. At this time, the temperature of the complete mixing reactor was adjusted to 135 ° C.
  • the polymer solution continuously discharged from the polymerization reactor is supplied to a vent type screw type extruder having a reduced pressure of 2.7 to 4.0 kPa to remove volatile matter, and the pellet-shaped copolymer A1 is removed.
  • the composition ratio of the monomer units in the copolymer A1 was 90 mol% for the styrene monomer and 10 mol% for the acrylic acid monomer, and the weight average molecular weight measured by GPC was 300,000.
  • Elecut S-412-2 (manufactured by Takemoto Yushi Co., Ltd.): sodium dodecylbenzenesulfonate 1-2: Epan 750 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): nonionic surfactant, polyalkylene Oxide block, ethylene oxide content: 50% 1-3: Stearyl alcohol ⁇ Preparation of impact reinforcement >> The following impact reinforcement was prepared as a compound (2) which is an additive described in Table 1 described later.
  • Ammonium persulfate (abbreviation: APS) 0.36 g was added, and after stirring for 5 minutes, methyl methacrylate (abbreviation: MMA) 1657 g, n-butyl acrylate (abbreviation: BA) 21.6 g, allyl methacrylate (abbreviation: ALMA) 1.68 g A mixture of monomers consisting of 1 and 2 was added all at once, and after detecting the exothermic peak, the mixture was further held for 20 minutes to complete the polymerization of the innermost hard layer.
  • MMA methyl methacrylate
  • BA n-butyl acrylate
  • ALMA allyl methacrylate
  • n-OM n-octyl mercaptan
  • the polymer latex thus obtained was put into a 3% by weight sodium sulfate aqueous solution, salted out and coagulated, then repeatedly dehydrated and washed, and then dried to obtain a three-layer structure.
  • Particles 1 which are acrylic particles were obtained.
  • the average particle size determined by the absorbance method was 100 nm.
  • the obtained emulsion polymerization liquid of elastic organic fine particles was salted out and solidified with calcium chloride, washed with water and dried to obtain particles 2 which are powdery elastic organic fine particles.
  • the volume average particle diameter of the elastic organic fine particles was 0.260 ⁇ m.
  • composition of dope 1 Copolymer A1 (styrene: 90 mol%, acrylic acid: 10 mol%, weight average molecular weight: 300,000) 100 parts by mass UV absorber 2- (2H-benzotriazol-2-yl) -6- (1-methyl-1 -Phenylethyl) -4- (1,1,3,3-tetramethylbutyl) phenol (Ti928 manufactured by BASF Japan) 3.0 parts by weight Matting agent R812 (manufactured by Nippon Aerosil Co., Ltd., silica particles, average particle size 8 nm) 0.30 parts by mass Compound (1): Compound 1-1 Peeling aid (Elecut S-412-2, sodium dodecylbenzenesulfonate, manufactured by Takemoto Yushi Co., Ltd.) 0.35 parts by mass Compound (2): Compound 2- 1 Impact reinforcement agent (styrene-butadiene copolymer) 1.0 part by mass Dichloromethane The dope 1 prepared 50 parts
  • the peeled film-like product was dried at a drying temperature of 135 ° C. while evaporating the solvent at 35 ° C. and stretching it 1.25 times in the width direction (TD direction) by tenter stretching.
  • the residual solvent amount at the start of stretching by zone stretching was 20.0%, and the residual solvent amount at the start of stretching by tenter was 8.0%.
  • a relaxation treatment was performed at 130 ° C. for 5 minutes, and then drying was completed while conveying a drying zone at 120 ° C. and 140 ° C. with a number of rollers.
  • the obtained film was slit to a width of 1.5 m, a knurling process having a width of 10 mm and a height of 5 ⁇ m was applied to both ends of the film, and then wound around a core to prepare a polarizing plate protective film 1.
  • the produced polarizing plate protective film 1 had a film thickness of 40 ⁇ m and a winding length of 4000 m.
  • Polarizer protective films 2 to 13 were produced in the same manner as in the production of the polarizing plate protective film 1 except that the copolymer A1 used for preparing the dope was changed to A2 to A13, respectively.
  • Polarizer protective films 14 and 15 were produced in the same manner except that the thickness of the polarizing plate protective film 4 was changed from 40 ⁇ m to 25 ⁇ m and 60 ⁇ m.
  • a polarizing plate protective film 16 was prepared in the same manner as in the production of the polarizing plate protective film 4 except that the compound (1) peeling aid (compound 1-1) and the compound (2) impact reinforcing agent were omitted.
  • a polarizing plate protective film 17 was produced in the same manner as in the production of the polarizing plate protective film 4 except that the compound (1) peeling aid (compound 1-1) was omitted.
  • Polarizing Plate protective films 27-30 In the production of the polarizing plate protective film 4, the amount of compound 2-1 (styrene-butadiene copolymer), which is an impact reinforcing agent for compound (2), was 0.3% by mass with respect to copolymer A4. Polarizing plate protective films 27 to 30 were produced in the same manner except that the content was changed to 2.5% by mass, 4.5% by mass, and 6.0% by mass.
  • a polarizing plate protective film 31 was produced by the melt casting method shown below.
  • the obtained pellets were put into a single screw extruder and melt kneaded at 250 ° C. in a nitrogen atmosphere. Then, it extruded from the die
  • Polarizing plate protective films 32 and 33 In the production of the polarizing plate protective film 4, polarizing plate protective films 32 and 33 were produced in the same manner except that the film thickness was changed from 40 ⁇ m to 18 ⁇ m and 65 ⁇ m, respectively.
  • Table 1 shows the structure of each polarizing plate protective film produced as described above.
  • a polarizing plate was produced according to the following method using each of the produced polarizing plate protective films.
  • This uniaxially stretched film was washed with water and dried to obtain a polarizer having a thickness of 10 ⁇ m.
  • the draw ratio was adjusted to produce polarizers having thicknesses of 3 ⁇ m, 5 ⁇ m, 15 ⁇ m, and 20 ⁇ m.
  • 3,4-Epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate 45 parts by mass Epolide GT-301 (alicyclic epoxy resin manufactured by Daicel Chemical Industries) 40 parts by mass 1,4-butanediol diglycidyl ether 15 parts by mass Triarylsulfonium hexafluorophosphate 2.3 parts by mass 9,10-dibutoxyanthracene 0.1 parts by mass 1,4-diethoxynaphthalene 2.0 parts by mass (3) Production of retardation film 1 A retardation film 1 (for T2 and T3) was produced according to the method described below.
  • a main dope having the following composition was prepared. First, after adding methylene chloride and ethanol to the pressure dissolution tank, the cellulose acetate, sugar ester 1, polycondensation ester, retardation increasing agent 1 and fine particle additive solution 1 having an acetyl group substitution degree of 2.40 are added with stirring. did. This was heated and dissolved completely with stirring. The obtained solution was used as Azumi filter paper No. manufactured by Azumi Filter Paper Co., Ltd. The main dope was prepared by filtration using 244.
  • ⁇ Composition of main dope> Methylene chloride 365 parts by weight Ethanol 50 parts by weight Cellulose acetate (acetyl substitution degree 2.40) 84 parts by weight Sugar ester 1: Saccharose benzoate having an average substitution degree of 5.5 10 parts by weight Polycondensation ester: (phthalic acid / adipic acid / 1 , 2-propanediol 25/75/100 molar ratio condensate with both ends sealed with benzoate groups, molecular weight 440) 3 parts by weight Retardation increasing agent (compound A below) 3 parts by weight addition of fine particles 1 part by mass of liquid 1
  • the obtained main dope was cast (cast) on a stainless belt support, and the solvent was evaporated until the amount of residual solvent in the formed web reached 75% by mass.
  • the obtained web was peeled from the stainless steel belt support with a peeling tension of 130 N / m.
  • the web obtained by peeling was stretched 30% in the width direction using a tenter while being heated at 150 ° C.
  • the residual solvent at the start of stretching was 15% by mass.
  • the drying zone was transported while being held by a large number of rolls to finish drying.
  • the drying temperature was 130 ° C. and the transport tension was 100 N / m.
  • a retardation film 1 having a dry film thickness of 35 ⁇ m was obtained.
  • the prepared polarizing plate protective film 1 was prepared as a polarizing plate protective film, and one surface side of the polarizing plate protective film 1 was subjected to corona discharge treatment in the same manner as described above.
  • the prepared active energy ray-curable adhesive liquid is applied to the surface side of the polarizing plate protective film 1 subjected to corona discharge treatment with a bar coater so that the film thickness after curing is about 3 ⁇ m. An active energy ray-curable adhesive layer was formed.
  • a polarizer bonded to one side of the retardation film 1 is bonded onto the active energy ray-curable adhesive layer of the polarizing plate protective film, and as shown in FIG. 1, the polarizing plate protective film 1 (10) Polarizing plate 1 in which / active energy ray-curable adhesive layer (103A 1 ) / polarizer (104) / active energy ray-curable adhesive layer (103A 2 ) / retardation film 1 (105) is laminated in this order Obtained.
  • the number in a parenthesis has shown the code number of each applicable structural member in FIG.
  • the polarizing plate 1 was disposed so that the slow axis of the retardation film 1 (105) and the absorption axis of the polarizer (104) were orthogonal to each other.
  • the polarizing plate 1 is configured so that the accumulated light amount is 750 mJ / cm 2 from the phase difference film 1 side using an ultraviolet irradiation device with a belt conveyor (the lamp uses a D bulb manufactured by Fusion UV Systems). Each active energy ray-curable adhesive layer was cured by irradiating with ultraviolet rays.
  • polarizing plates 32 to 35 In the production of the polarizing plate 4, polarizing plates 32 to 35 were produced in the same manner except that the polarizers having thicknesses of 3 ⁇ m, 5 ⁇ m, 15 ⁇ m, and 20 ⁇ m were used instead of the 10 ⁇ m thick polarizer, respectively. did.
  • polarizer a 10 ⁇ m-thick polarizer similar to that used for the production of the polarizing plate 4 was used.
  • the retardation film 1 was bonded to one side of the polarizer, and the polarizing plate protective film 4 was bonded to the back side of the polarizer to prepare a polarizing plate 36.
  • Step 1 Corona discharge treatment was performed on the surfaces of the retardation film 1 and the polarizing plate protective film 4.
  • the conditions for the corona discharge treatment were a corona output intensity of 2.0 kW and a line speed of 18 m / min.
  • Step 2 A polarizer having a thickness of 10 ⁇ m was immersed in a polyvinyl alcohol adhesive tank having a solid content of 2% by mass for 1 to 2 seconds.
  • Step 3 Excess polyvinyl alcohol adhesive adhered to the polarizer in Step 2 was lightly wiped off and placed on the retardation film 1 treated in Step 1. Subsequently, the polarizing plate protective film 4 was arrange
  • Step 4 A polarizing plate protective film 4 is placed on the side of the polarizer opposite to the side on which the retardation film 1 of the laminate produced in Step 3 is placed, the pressure is 20 to 30 N / cm 2 , and the conveyance speed is Bonding was performed at about 2 m / min.
  • Process 5 The laminated body which bonded the polarizer produced in the process 4, the phase difference film 1, and the polarizing plate protective film 4 in the 80 degreeC dryer was dried for 2 minutes, and the polarizing plate 36 was produced.
  • a VA liquid crystal cell (107) having two glass substrates having a thickness of 0.5 mm and a liquid crystal layer disposed therebetween was prepared. Then, the prepared polarizing plate 1 (101A and 1010B) is attached to both sides of the prepared liquid crystal cell (107) via a 25 ⁇ m thick double-sided tape (substrate-less tape MO-3005C) manufactured by Lintec.
  • the liquid crystal display panel (106) was obtained by pasting together so as to have the structure shown in FIG. As shown in FIG. 3, the lamination was performed such that the retardation films 1 (105A and 105B) of the polarizing plates 1 (101A and 1010B) were in contact with the glass substrate of the liquid crystal cell (107).
  • the polarizing plate protective film (102A) is the polarizing plate protective film T1 referred to in the present invention
  • the polarizing plate protective film (102B) is the polarizing plate protective film T4 referred to in the present invention.
  • the retardation film (105A) in contact with the liquid crystal cell (107) is the retardation film T2 referred to in the present invention
  • the retardation film (105B) is the retardation film T3 referred to in the present invention.
  • the produced liquid crystal display panel 1 (106) was arranged, and the liquid crystal display device 1 was produced.
  • the absorption axis of the polarizing plate of the attached liquid crystal display panel 1 (106) was the same direction as the absorption axis of the polarizing plate previously stuck.
  • the number in a parenthesis has shown the code number of the corresponding structural member in FIG.
  • liquid crystal display devices 2 to 38 In the production of the liquid crystal display device 1, the liquid crystal display device 2 is similarly manufactured except that the polarizing plates 1 (101A and 1010B) constituting the liquid crystal display panel 1 (106) are changed to the polarizing plates 2 to 38, respectively. ⁇ 38 were produced.
  • each polarizing plate was allowed to stand for 120 hours in an environment of 80 ° C. and 90% RH, and then left for 24 hours in an environment of 23 ° C. and 55% RH, and the degree of polarization 2 (%) was calculated in the same manner. .
  • the degree of polarization decrease 2 was obtained according to the following formula (3), and this was determined as the stability of the polarizer.
  • a scale force deterioration 2
  • Each liquid crystal display device was left in an environment of 40 ° C. and 95% RH for 24 hours.
  • the liquid crystal display device displaying black in a 40 ° C. dry environment, the difference between the luminance near the four vertices of the display screen and the luminance near the center of the display screen (image unevenness between the central portion and the peripheral portion) was visually observed and evaluated for bend unevenness resistance based on the following criteria.
  • a film prepared from a copolymer (A) composed of the aromatic vinyl monomer defined in the present invention and an unsaturated carboxylic acid monomer or unsaturated dicarboxylic anhydride monomer is high in the forced deterioration test. It can be seen that it has stability and has an excellent resistance to vent unevenness when it is provided in a liquid crystal display device.
  • a polarizing plate using a polarizing plate protective film prepared from an aromatic vinyl monomer defined in the present invention and a copolymer (A) composed of an unsaturated carboxylic acid monomer or an unsaturated dicarboxylic acid anhydride monomer It can be seen that when the thickness of the polarizer is in the range of 5.0 to 15 ⁇ m, both the polarizer stability and the resistance to bent unevenness in a high temperature and high humidity environment are excellent.
  • the polarization degree fluctuation range in a high temperature and high humidity environment is more than 1.0, and the film thickness of the polarizer is as described above. It can be seen that the occurrence of uneven venting is significant in the liquid crystal display device using the polarizing plate 35 that is not less than the specified range.
  • the thickness of the polarizing plate protective film in the sample in which the thickness of the polarizing plate protective film is changed from 18 to 65 ⁇ m, the thickness is 25 ⁇ m (polarizing plate 14), 40 ⁇ m (polarizing plate 4), 60 ⁇ m ( The polarizing plate 15) exhibits an excellent effect, but the polarizing plate 37 using a polarizing plate protective film having a film thickness of 18 ⁇ m, or the polarizing plate 38 using a polarizing plate protective film having a film thickness of 65 ⁇ m. Then, it can be seen that the stability of the polarizer and the resistance to bent unevenness are slightly deteriorated.
  • the polarizing plate or the liquid crystal display device of the present invention when the effects of the polarizing plates 1, 4, 7, and 11 to 13 are verified, styrene is used as the aromatic vinyl monomer (the polarizing plate 4 and the polarizing plate 9). Comparison), using methacrylic acid as an unsaturated carboxylic acid monomer (comparison between polarizing plate 4 and polarizing plates 1 and 14), using maleic anhydride as an unsaturated dicarboxylic acid anhydride monomer (polarizing plate 7, It can be seen that the comparison of the polarizing plates 12 and 13 exhibits a more excellent effect.
  • a compound (compound) selected from acids, alcohols, metal salts, nonionic surfactants and nonreactive quaternary ammonium salt type surfactants having a linear or branched alkyl group having 8 to 22 carbon atoms It can be seen that by adding (1)), the isolation performance is improved and the foreign matter failure resistance is improved.
  • the polarizing plate 4 and the polarizing plate 31 are compared, it can be seen that, by applying the solution casting method as the method for forming the polarizing plate protective film, the foreign matter failure resistance and the polarizer stability are more excellent.
  • the adhesive method (polarizing plate 4) with the active energy ray curable adhesive is superior to the water paste method (polarizing plate 36) as the bonding method, so that the polarizer stability and vent unevenness resistance are more excellent. I understand.
  • the present invention was constructed in which the polarizing plate protective film having a film thickness in the range of 20 to 60 ⁇ m was used and the thickness of the polarizer was in the range of 5.0 to 15 ⁇ m with the monomer configuration according to the present invention.
  • the polarizing plate can provide a liquid crystal display device that is excellent in polarizer stability, includes the same, and suppresses occurrence of display unevenness (bend unevenness).
  • Example 2 ⁇ Production of polarizing plate> [Production of Polarizing Plate 51]
  • a polarizing plate 51 was produced in the same manner except that the polarizing plate protective film 3 was used instead of the retardation film 1 as the retardation film (105).
  • Zeone ZF14 film (film thickness: 100 ⁇ m) manufactured by Nippon Zeon Co., Ltd. was used.
  • liquid crystal display devices 51 to 55 were produced in the same manner as described in Example 1.
  • the polarizing plate of the present invention has high polarizer stability when stored in a high-temperature and high-humidity environment, and can be applied to various drive-type liquid crystal display devices. Even so, it is possible to obtain a liquid crystal display device having excellent visibility such as unevenness of the liquid crystal display device.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Nonlinear Science (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Polarising Elements (AREA)
  • Liquid Crystal (AREA)
  • Paints Or Removers (AREA)
  • Adhesives Or Adhesive Processes (AREA)

Abstract

La présente invention concerne : une plaque de polarisation qui présente une grande stabilité de polarisation dans les cas où la plaque de polarisation est stockée dans un environnement à haute température et à humidité élevée ; et un dispositif d'affichage à cristaux liquides sans irrégularités d'affichage (irrégularités dues à la flexion). Une plaque de polarisation selon l'invention présente une configuration dans laquelle un polariseur, qui est fait d'une résine d'alcool polyvinylique, est retenu entre un film de protection de plaque de polarisation et un film de retard. Ladite plaque de polarisation est caractérisée en ce que : le film de protection de plaque de polarisation contient un copolymère (A) d'au moins un monomère de vinyle aromatique et d'un monomère d'acide carboxylique insaturé ou d'un monomère anhydride d'acide dicarboxylique insaturé, et il présente une épaisseur de film dans la plage allant de 20 à 60 µm ; et le polariseur présente une épaisseur de film dans la plage allant de 5,0 à 15 µm.
PCT/JP2015/058461 2014-04-16 2015-03-20 Plaque de polarisation et dispositif d'affichage à cristaux liquides WO2015159645A1 (fr)

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JP2017203984A (ja) * 2016-05-10 2017-11-16 住友化学株式会社 光学フィルム、及びこれを用いたフレキシブルデバイス
WO2018008579A1 (fr) * 2016-07-06 2018-01-11 デンカ株式会社 Composition de résine pour films protecteurs de polariseur, et film protecteur de polariseur
JP2018155813A (ja) * 2017-03-15 2018-10-04 日東電工株式会社 偏光子保護フィルムの製造方法
WO2020027085A1 (fr) * 2018-07-31 2020-02-06 コニカミノルタ株式会社 Film optique, plaque de polarisation et procédé de production de film optique
WO2020026960A1 (fr) * 2018-07-31 2020-02-06 コニカミノルタ株式会社 Film optique, film protecteur de plaques de polarisation, et plaque de polarisation
JP2021033058A (ja) * 2019-08-23 2021-03-01 コニカミノルタ株式会社 光学フィルム用ドープの製造方法、光学フィルム用ドープ、光学フィルム、偏光板および光学フィルムの製造方法

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KR102112863B1 (ko) * 2016-12-23 2020-05-19 삼성에스디아이 주식회사 편광판 및 이를 포함하는 광학표시장치

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JP2010096919A (ja) * 2008-10-15 2010-04-30 Asahi Kasei Chemicals Corp 光学フィルム
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Publication number Priority date Publication date Assignee Title
JP2017203984A (ja) * 2016-05-10 2017-11-16 住友化学株式会社 光学フィルム、及びこれを用いたフレキシブルデバイス
WO2018008579A1 (fr) * 2016-07-06 2018-01-11 デンカ株式会社 Composition de résine pour films protecteurs de polariseur, et film protecteur de polariseur
JPWO2018008579A1 (ja) * 2016-07-06 2019-04-25 デンカ株式会社 偏光子保護フィルム用樹脂組成物、偏光子保護フィルム
JP2018155813A (ja) * 2017-03-15 2018-10-04 日東電工株式会社 偏光子保護フィルムの製造方法
WO2020027085A1 (fr) * 2018-07-31 2020-02-06 コニカミノルタ株式会社 Film optique, plaque de polarisation et procédé de production de film optique
WO2020026960A1 (fr) * 2018-07-31 2020-02-06 コニカミノルタ株式会社 Film optique, film protecteur de plaques de polarisation, et plaque de polarisation
JPWO2020027085A1 (ja) * 2018-07-31 2021-08-02 コニカミノルタ株式会社 光学フィルム、偏光板、および光学フィルムの製造方法
JPWO2020026960A1 (ja) * 2018-07-31 2021-08-05 コニカミノルタ株式会社 光学フィルム、偏光板保護フィルムおよび偏光板
JP7314942B2 (ja) 2018-07-31 2023-07-26 コニカミノルタ株式会社 光学フィルム、偏光板保護フィルムおよび偏光板
JP7533217B2 (ja) 2018-07-31 2024-08-14 コニカミノルタ株式会社 光学フィルム、偏光板、および光学フィルムの製造方法
JP2021033058A (ja) * 2019-08-23 2021-03-01 コニカミノルタ株式会社 光学フィルム用ドープの製造方法、光学フィルム用ドープ、光学フィルム、偏光板および光学フィルムの製造方法
JP7379933B2 (ja) 2019-08-23 2023-11-15 コニカミノルタ株式会社 光学フィルム用ドープの製造方法および光学フィルムの製造方法

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