WO2022085726A1 - 偏光板およびその製造方法、ならびに表示装置の製造方法 - Google Patents

偏光板およびその製造方法、ならびに表示装置の製造方法 Download PDF

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Publication number
WO2022085726A1
WO2022085726A1 PCT/JP2021/038792 JP2021038792W WO2022085726A1 WO 2022085726 A1 WO2022085726 A1 WO 2022085726A1 JP 2021038792 W JP2021038792 W JP 2021038792W WO 2022085726 A1 WO2022085726 A1 WO 2022085726A1
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Prior art keywords
protective film
polarizing plate
film
light
polarizing
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PCT/JP2021/038792
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English (en)
French (fr)
Japanese (ja)
Inventor
淳 原
崇 南條
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コニカミノルタ株式会社
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Priority to CN202180071096.9A priority Critical patent/CN116324943A/zh
Priority to JP2022557585A priority patent/JPWO2022085726A1/ja
Priority to KR1020237013137A priority patent/KR20230067679A/ko
Publication of WO2022085726A1 publication Critical patent/WO2022085726A1/ja

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B23/00—Layered products comprising a layer of cellulosic plastic substances, i.e. substances obtained by chemical modification of cellulose, e.g. cellulose ethers, cellulose esters, viscose
    • B32B23/20—Layered products comprising a layer of cellulosic plastic substances, i.e. substances obtained by chemical modification of cellulose, e.g. cellulose ethers, cellulose esters, viscose comprising esters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
    • B32B27/325—Layered products comprising a layer of synthetic resin comprising polyolefins comprising polycycloolefins
    • 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
    • G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
    • G02B1/14—Protective coatings, e.g. hard coatings
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/003—Light absorbing elements
    • 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
    • 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
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements

Definitions

  • the present invention relates to a polarizing plate, a method for manufacturing the same, and a method for manufacturing a display device.
  • Display panels such as liquid crystal panels and organic EL panels usually include a polarizing plate.
  • the polarizing plate includes a polarizing element and two protective films (optical films) sandwiching the polarizing element.
  • Such a polarizing plate is manufactured by laminating a polarizing element and two protective films by roll-to-roll, and then cutting (cutting) the obtained laminate to a size suitable for a display panel.
  • the polarizing plate has been cut and processed using laser light (see, for example, Patent Documents 1 and 2).
  • a method for cutting a laminated film of a plurality of resin layers having different materials a method of cutting using laser light having a different wavelength depending on the type of the resin layer is known (for example, Patent Document 1).
  • a method of cutting to a depth in the middle with a laser beam and then physically tearing and cutting for example, Patent Document 2.
  • Patent Documents 1 and 2 a laminate obtained by laminating a cellulose triacetate film (TAC) on one surface of a polarizing element and a cycloolefin resin film on the other surface is cut by laser light.
  • TAC cellulose triacetate film
  • a display device manufactured using such a polarizing plate has a problem that display unevenness is likely to occur at the edge of the display screen.
  • the present invention has been made in view of the above circumstances, and is a polarizing plate capable of cutting with a laser beam without deteriorating productivity and capable of suppressing display unevenness at the end of a display device, and manufacturing thereof. It is an object of the present invention to provide a method as well as a method of manufacturing a display device.
  • the present invention relates to the following polarizing plate and a method for manufacturing the same, and a method for manufacturing a display device.
  • the polarizing plate of the present invention comprises a polarizing element, a first protective film arranged on one surface of the polarizing element, a second protective film arranged on the other surface of the polarizing element, and the first protective film. It is a polarizing plate in which a release film arranged on the surface opposite to the polarizing element is laminated, and the absorption of light having a wavelength of 9.4 ⁇ m measured by the ATR method of the second protective film.
  • the coefficient A2 is 1.0 ⁇ 10 2 to 4.5 ⁇ 10 2 / ⁇ m, and the polarizing plate has a cut end face, and the cut end face of the polarizing plate in a cross section along the stacking direction.
  • the inclination angle of the straight line connecting the end point P1 on the side opposite to the first protective film of the release film and the end point P2 on the second protective film side of the polarizing element with respect to the stacking direction is 0. It is 5 to 10 °.
  • the method for manufacturing a polarizing plate of the present invention comprises a polarizing element, a first protective film arranged on one surface of the polarizing element, a second protective film arranged on the other surface of the polarizing element, and the first protective film.
  • the method for manufacturing a display device of the present invention includes a step of attaching the polarizing plate of the present invention to at least one surface of the display element so that the second protective film is on the display element side.
  • an optical film, a polarizing plate and a liquid crystal display device capable of improving the cutting property by laser light without causing light leakage in the display device.
  • 1A and 1B are cross-sectional views showing a part of a manufacturing process of a display device using a conventional polarizing plate.
  • 2A and 2B are cross-sectional views showing a part of a manufacturing process of a display device using another conventional polarizing plate.
  • 3A and 3B are cross-sectional views showing a part of a manufacturing process of a display device using a polarizing plate according to the present embodiment.
  • 4A is a cross-sectional view showing the configuration of the polarizing plate according to the present embodiment
  • FIG. 4B is an enlarged view of the cut surface of FIG. 4A.
  • 5A to 5C are cross-sectional views showing a manufacturing process of the polarizing plate according to the present embodiment.
  • FIG. 6 is a cross-sectional view showing the configuration of the display device according to the present embodiment.
  • the present inventors have investigated the cause of display unevenness at the edge of a display screen in a display device using a conventional polarizing plate cut by laser light (for example, the polarizing plate of Patent Document 1 or 2). It was found that the inclination angle of the cut end face of the polarizing plate after cutting with light is related. That is, although the mechanism that causes display unevenness at the edges is not clear, it is presumed as follows.
  • FIGS. 1A and 1B are cross-sectional views showing a part of a manufacturing process of a display device using a conventional polarizing plate.
  • 3A and 3B are cross-sectional views showing a part of a manufacturing process of a display device using a polarizing plate according to the present embodiment.
  • the inclination of the cut end face of the polarizing plate 10 before being attached to the display element C is made gentle (see FIG. 3A). Specifically, the inclination angle of the cut end face of the polarizing plate 10 is adjusted to 0.5 to 10 ° in the cross section along the laminating direction of each film (see FIG. 4B described later). As a result, the inclination angle of the cut end surface of the polarizing plate after being attached to the display element C can be made close to almost 0 ° (it can be made substantially perpendicular to the surface of the display element C) (see FIG. 3B). It is possible to suppress display unevenness at the edge of the display screen due to the tilt angle (shape) of the cut end face.
  • the inclination angle of the cut end face of the polarizing plate 10 can be adjusted by any method. Above all, the inclination angle of the cut end surface of the polarizing plate 10 is preferably adjusted by the absorbance of the laser light of the first protective film 12 and the second protective film 13 and their ratio. Specifically, the ratio of the absorbance of the laser light of the first protective film 12 and the second protective film 13 is appropriately reduced; that is, the extinction coefficient of the light having a wavelength of 9.4 ⁇ m of the second protective film 13 is appropriately reduced.
  • the ratio A1 / A2 of the extinction coefficient A1 of the first protective film 12 to the extinction coefficient A2 of the second protective film 13 is moderately increased (1.0 ⁇ 10 2 to 4.5 ⁇ 10 2 / ⁇ m). It is preferable to make it small.
  • the configuration of the present invention will be described.
  • FIG. 4A is a cross-sectional view showing the configuration of the polarizing plate 10 according to the present embodiment
  • FIG. 4B is an enlarged view of the cut surface of FIG. 4A.
  • the illustration of the adhesive layer is omitted.
  • the polarizing plate 10 includes a polarizing element 11, a first protective film 12 arranged on one surface thereof, and a second protective film arranged on the other surface. 13 and a release film 14 arranged on the surface opposite to the polarizing element 11 via the first protective film 12.
  • An adhesive layer (not shown) is arranged between the polarizing element 11 and the first protective film 12 or the second protective film 13.
  • the polarizing element 11 is an element that allows only light on a plane of polarization in a certain direction to pass through, and is a polyvinyl alcohol-based polarizing film.
  • the polyvinyl alcohol-based polarizing film includes a polyvinyl alcohol-based film dyed with iodine and a polyvinyl alcohol-based film dyed with a dichroic dye.
  • the polyvinyl alcohol-based polarizing film may be a film obtained by uniaxially stretching a polyvinyl alcohol-based film and then dyeing it with iodine or a bicolor dye (preferably a film further subjected to a durability treatment with a boron compound); polyvinyl.
  • An alcohol-based film may be a film that has been dyed with iodine or a bicolor dye and then uniaxially stretched (preferably a film that has been further subjected to a durability treatment with a boron compound).
  • the absorption axis of the modulator is parallel to the maximum stretching direction.
  • the thickness of the polarizing element 11 is preferably 5 to 40 ⁇ m, and more preferably 5 to 30 ⁇ m in order to reduce the thickness of the polarizing plate.
  • First protective film 12 The first protective film 12 is arranged on one surface of the polarizing element 11, specifically between the polarizing element 11 and the release film 14. The first protective film 12 is arranged on the side opposite to the display element (the side away from the display element) via the polarizing element 11 when the display device is used.
  • the resin constituting the first protective film 12 is not particularly limited, and is a resin having transparency and having an extinction coefficient ratio A1 / A2 of the first protective film 12 and the second protective film 13 being constant or less. It should be. Examples of such resins include polyester resins, (meth) acrylic resins, cellulose ester resins (TAC films and the like), cycloolefin resins and the like. Above all, the first protective film preferably contains a (meth) acrylic resin or a cycloolefin resin.
  • the (meth) acrylic resin is preferably a polymer containing a structural unit derived from methyl methacrylate.
  • the polymer may further contain structural units derived from a monomer copolymerizable with methyl methacrylate.
  • Examples of other monomers copolymerizable with methylmethacrylate are alkyl (meth) acrylates with 1-18 carbon atoms other than methylmethacrylate, such as 2-ethylhexylmethacrylate; ⁇ , ⁇ -non, such as (meth) acrylic acid.
  • Saturated acid unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid; styrenes such as styrene and ⁇ -methylstyrene; maleic anhydride; maleimides such as maleimide and N-phenylmaleimide; included.
  • the content ratio of the structural unit derived from methyl methacrylate with respect to all the structural units constituting the copolymer is preferably 50% by mass or more, and more preferably 70% by mass or more.
  • Cycloolefin resin As the cycloolefin resin, the same cycloolefin resin contained in the second protective film 13 described later can be used. That is, the composition of the cycloolefin resin contained in the first protective film may be the same as or different from the composition of the cycloolefin resin contained in the second protective film.
  • the weight average molecular weight of the (meth) acrylic resin and the cycloolefin resin can be in the same range as the weight average molecular weight of the cycloolefin resin described later.
  • the thickness of the first protective film 12 is not particularly limited, but is preferably 20 to 70 ⁇ m, and more preferably 30 to 60 ⁇ m.
  • Second protective film 13 The second protective film 13 is arranged on the other surface of the polarizing element 11. Specifically, the second protective film 13 is arranged between the display element and the polarizing element 11 (the side closer to the display element than the polarizing element 11) when the display device is used.
  • the material of the second protective film 13 is preferably one in which the ratio A1 / A2 of the absorption coefficients of the first protective film 12 and the second protective film 13 is 1 to 5.
  • A1 / A2 is 1 or more, it is easy to cut the polarizing plate in a shorter time.
  • the second protective film 13 has an appropriate absorption of laser light (the absorption of laser light of the second protective film 13 is lower than that of the first protective film 12). (Because it is not too much), the amount of shrinkage due to cutting can be reduced. As a result, the inclination angle of the cut end surface 10a of the obtained polarizing plate 10 can be easily reduced.
  • the ratio A1 / A2 of the absorption coefficient is preferably 1.5 to 5.0, more preferably 2.0 to 4.5.
  • the extinction coefficient A2 of the light having a wavelength of 9.4 ⁇ m of the second protective film 13 is preferably 1.0 ⁇ 10 2 to 4.5 ⁇ 10 2 / ⁇ m.
  • the absorption coefficient A2 is 1.0 ⁇ 10 2 / ⁇ m or more, the laser light can be appropriately absorbed, so that the cutting property by the laser light can be improved.
  • the absorption coefficient A2 of the second protective film 13 is 1.5 ⁇ 10 2 to 4.0 ⁇ 10 2 / ⁇ m from the viewpoint that transparency is not easily impaired and light leakage in the display device is less likely to occur. More preferably, it is 2.0 ⁇ 10 2 to 3.5 ⁇ 10 2 / ⁇ m.
  • the absorption coefficient A1 of the first protective film 12 and the absorption coefficient A2 of the second protective film 13 can be measured by the following methods, respectively.
  • ATR method Attenuated Total Reflection
  • FTIR FT-IR
  • incident light diameter 100 ⁇ m
  • prism Ge (incident angle 45 °)
  • detector The infrared absorption spectrum was measured under the conditions of MCT-A, resolution: 4.0 cm -1 , integration: 64 times. From the obtained infrared absorption spectrum, the absorbance of the portion (frequency 1041 cm -1 ) corresponding to the wavelength of 9.4 ⁇ m is read.
  • the extinction coefficient of the film can be obtained based on the following formula.
  • Absorption coefficient (/ ⁇ m) Absorbance x loge10 / Film thickness ( ⁇ m)
  • the extinction coefficient of the film can be adjusted mainly by the composition of the film.
  • the composition of the second protective film 13 may be any as long as it satisfies the above absorption characteristics, and is not particularly limited, but preferably contains a cycloolefin resin, and more preferably contains a light absorption material. That is, the second protective film 13 preferably contains a cycloolefin resin and a light absorbing material.
  • Cycloolefin resin is a polymer containing structural units derived from norbornene-based monomers.
  • the norbornene-based monomer is represented by the following formula (1).
  • R 1 to R 4 of the formula (1) represent a hydrogen atom, a halogen atom, a hydrocarbon group, or a polar group, respectively.
  • halogen atoms include fluorine atoms and chlorine atoms.
  • the hydrocarbon group is a hydrocarbon group having 1 to 10, preferably 1 to 4, more preferably 1 or 2 carbon atoms.
  • hydrocarbon groups include alkyl groups such as methyl group, ethyl group, propyl group and butyl group.
  • the hydrocarbon group further has a divalent linking group of a linking group containing an oxygen atom, a nitrogen atom, a sulfur atom or a silicon atom (eg, a carbonyl group, an imino group, an ether bond, a silyl ether bond, a thioether bond, etc.). May be.
  • polar groups include linking groups such as carboxy group, hydroxy group, alkoxy group, alkoxycarbonyl group, allyloxycarbonyl group, amino group, amide group, and methylene group (-(CH 2 ) n- , n is 1 A group to which these groups are bonded via the above integer) is included.
  • linking groups such as carboxy group, hydroxy group, alkoxy group, alkoxycarbonyl group, allyloxycarbonyl group, amino group, amide group, and methylene group (-(CH 2 ) n- , n is 1
  • alkoxycarbonyl group and an aryloxycarbonyl group are preferable, and an alkoxycarbonyl group is more preferable.
  • R 1 to R 4 is a polar group.
  • a cycloolefin resin containing a structural unit derived from a norbornene-based monomer having a polar group is easily dissolved in a solvent, for example, when forming a film by a solution casting method, and the glass transition temperature of the obtained film is easily increased. Is.
  • a cycloolefin resin containing no structural unit derived from a norbornene-based monomer having a polar group may be used.
  • both R 1 and R 2 may be hydrogen atoms.
  • P in the equation (1) indicates an integer of 0 to 2. From the viewpoint of increasing the heat resistance of the second protective film, p is preferably 1 to 2.
  • norbornene-based monomer represented by the formula (1) Specific examples of the norbornene-based monomer represented by the formula (1) are shown below. Among these, examples of norbornene-based monomers having a polar group include the following.
  • Examples of norbornene-based monomers having no polar group include:
  • the content of the structural unit derived from the norbornene-based monomer can be 50 to 100 mol% with respect to all the structural units constituting the cycloolefin resin.
  • the cycloolefin resin may further contain a structural unit derived from a norbornene-based monomer and a structural unit derived from another copolymerizable monomer.
  • examples of other copolymerizable monomers include norbornene-based monomers having no polar group (if the above-mentioned norbornene-based monomer has a polar group), cyclobutene, cyclopentene, cycloheptene, cyclooctene, etc. Cycloolefin-based monomers having no norbornene skeleton such as dicyclopentadiene are included.
  • cycloolefin resin a commercially available product may be used.
  • examples of commercial products include JSR's Arton (ARTON: Registered Trademark) G, Arton F, Arton R, and Arton RX.
  • the weight average molecular weight Mw of the cycloolefin resin is not particularly limited, but is preferably 20,000 to 300,000, more preferably 30,000 to 250,000, and even more preferably 40,000 to 200,000.
  • the weight average molecular weight Mw of the cycloolefin resin is in the above range, the mechanical properties of the second protective film 13 can be enhanced without impairing the molding processability.
  • the weight average molecular weight Mw of the cycloolefin resin can be measured by gel permeation chromatography (GPC). Specifically, gel permeation chromatography (HLC8220GPC manufactured by Tosoh Corporation) is used as the measuring device, and TSK-GEL G6000HXL-G5000HXL-G5000HXL-G4000HXL-G3000HXL series manufactured by Tosoh Corporation is used as the column. Then, 20 ⁇ 0.5 mg of the sample is dissolved in 10 ml of tetrahydrofuran and filtered through a 0.45 mm filter. 100 ml of this solution is injected into the above column (temperature 40 ° C.), measured with a detector RI at a temperature of 40 ° C., converted to styrene, and the weight average molecular weight is obtained.
  • GPC gel permeation chromatography
  • the glass transition temperature Tg of the cycloolefin resin is usually preferably 110 ° C. or higher, more preferably 110 to 350 ° C., and even more preferably 120 to 250 ° C.
  • the Tg of the cycloolefin resin is 110 ° C. or higher, deformation is unlikely to occur even under high temperature conditions.
  • the Tg is 350 ° C. or lower, the molding processability is not easily impaired, and the thermal deterioration of the cycloolefin resin during the molding process can be further suppressed.
  • the glass transition temperature can be measured by a method compliant with JIS K7121-2012 using DSC (Differential Scanning Colorimetry).
  • the content of the cycloolefin resin is not particularly limited, but is preferably 50% by mass or more, and more preferably 70 to 99% by mass with respect to the second protective film 13.
  • the light absorption material is usually preferably a compound having a carbonyl group, more preferably an ester compound or (meth) acrylic polymer particles.
  • the ester compound may be any of a sugar ester compound, a polycondensation ester compound, and a polyhydric alcohol ester compound.
  • sugar ester compound Glycoester compounds are compounds in which all or part of the OH groups of monosaccharides, disaccharides or trisaccharides are esterified.
  • a sugar ester compound is preferably a compound represented by the following formula (FA).
  • R 1 to R 8 in the formula (FA) represent a substituted or unsubstituted alkylcarbonyl group or a substituted or unsubstituted arylcarbonyl group.
  • R 1 to R 8 may be the same as or different from each other.
  • the substituted or unsubstituted alkylcarbonyl group is preferably a substituted or unsubstituted alkylcarbonyl group having 2 or more carbon atoms.
  • substituted or unsubstituted alkylcarbonyl groups include methylcarbonyl groups (acetyl groups), ethylcarbonyl groups and the like.
  • substituents contained in alkyl groups include aryl groups such as phenyl groups.
  • the substituted or unsubstituted arylcarbonyl group is preferably a substituted or unsubstituted arylcarbonyl group having 7 or more carbon atoms.
  • arylcarbonyl groups include phenylcarbonyl groups.
  • substituents contained in aryl groups include alkyl groups such as methyl groups.
  • the average degree of substitution of the sugar ester compound is preferably 3 to 6.
  • the average degree of substitution of the sugar ester compound indicates the average ratio of esterified to the total number of OH groups of the raw sugar.
  • the polyhydric alcohol ester is an esterified product of a divalent or higher aliphatic polyhydric alcohol (preferably a divalent to 20-valent aliphatic polyhydric alcohol) and a monocarboxylic acid.
  • polyhydric alcohols examples include adonitol, arabitol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2.
  • the monocarboxylic acid is not particularly limited, and is an aliphatic monocarboxylic acid such as acetic acid and propionic acid, an alicyclic monocarboxylic acid such as cyclopentanecarboxylic acid and cyclohexanecarboxylic acid, and an aromatic monocarboxylic acid such as benzoic acid and toluyl acid. It may be any of the acids.
  • the carboxylic acid used in the polyhydric alcohol ester compound may be one kind or a mixture of two or more kinds. Further, all the OH groups in the polyhydric alcohol may be esterified, or a part of them may remain as OH groups.
  • the molecular weights of the sugar ester compound and the polyhydric alcohol ester compound depend on the method for producing the second protective film, but are preferably moderately low from the viewpoint of facilitating good compatibility with the cycloolefin resin.
  • the molecular weight of the sugar ester compound or the ester compound can be, for example, 300 to 1500, preferably 600 to 1200.
  • the polycondensation ester compound is a polycondensate (polymer) containing a structural unit obtained by reacting a dicarboxylic acid with a diol.
  • the dicarboxylic acid may be any of an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, and an alicyclic dicarboxylic acid, and is preferably an aromatic dicarboxylic acid.
  • the dicarboxylic acid may be one kind or a mixture of two or more kinds. It is preferable to mix the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid.
  • the diol may be any of an aromatic diol, an aliphatic diol, and an alicyclic diol, preferably an aliphatic diol, and more preferably a diol having 1 to 4 carbon atoms.
  • the diol may be one kind or a mixture of two or more kinds.
  • the polycondensation ester compound preferably contains a structural unit obtained by reacting a dicarboxylic acid containing an aromatic dicarboxylic acid with a diol having 1 to 8 carbon atoms, and the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid are preferable. It is more preferable to contain a structural unit obtained by reacting a dicarboxylic acid containing the above with a diol having 1 to 8 carbon atoms. Both ends of the molecule of the polycondensation ester may or may not be sealed.
  • the sugar ester compound is particularly preferable in that the molecular weight is moderately low and the compatibility with the cycloolefin resin is excellent.
  • the (meth) acrylic polymer particles are polymer particles containing structural units derived from (meth) acrylates, and are preferably polymer particles containing structural units derived from methyl methacrylate.
  • the polymer containing a structural unit derived from methyl methacrylate may further contain a structural unit derived from another copolymerization monomer.
  • Examples of other copolymerized monomers include alkyl (meth) acrylates having 1 to 18 carbon atoms other than methyl methacrylate; ⁇ , ⁇ -unsaturated acids such as (meth) acrylic acid; maleic acid, fumaric acid, and itacon.
  • Unsaturated dicarboxylic acids such as acids; styrenes such as styrene and ⁇ -methylstyrene; (poly) ethylene glycol di (meth) acrylates, butanediol di (meth) acrylates, ethylene glycol di (meth) acrylates, triethylene glycol di
  • Polyfunctional (meth) acrylic acid esters having two or more (meth) acrylic groups such as (meth) acrylate and tetraethylene glycol di (meth) acrylate; allyl such as allyl (meth) acrylate and allylalkyl (meth) acrylate.
  • Polyfunctional monomers such as alkyl (meth) acrylates are included.
  • the polymer is preferably a crosslinked polymer, that is, a copolymer containing a structural unit derived from methyl methacrylate and a structural unit derived from a polyfunctional monomer; derived from methyl methacrylate. It is more preferable that the copolymer contains a structural unit, a structural unit derived from styrenes, and a structural unit derived from polyfunctional monomers.
  • the content of the structural unit derived from the (meth) acrylates containing a carbonyl group is a certain level or more.
  • the total amount of structural units derived from methyl methacrylate is preferably 30 mol% or more, more preferably 50 to 80 mol%, based on all the structural units constituting the polymer.
  • the content of the structural units derived from the polyfunctional monomer is preferably 3 to 50 mol%, more preferably 10 to 35 mol%, based on the total of all the structural units constituting the polymer.
  • the (meth) acrylic polymer particles are preferably a polymer having a refractive index difference of 0.01 or less from the cycloolefin resin. Such (meth) acrylic polymer particles do not easily reduce the transparency of the obtained second protective film.
  • the refractive index of the cycloolefin resin and the (meth) acrylic polymer particles can be the refractive index of light having a wavelength of 550 nm, respectively.
  • the refractive index of light having a wavelength of 550 nm is determined, for example, by preparing a sample film containing each component independently and measuring the refractive index of light having a wavelength of 550 nm of the sample film using a spectroscopic ellipsometer UVSEL manufactured by Horiba. be able to.
  • the Tg of the (meth) acrylic polymer particles is preferably 80 ° C. or higher.
  • the Tg of the (meth) acrylic polymer particles can be measured in accordance with JISK7121-2012 or ASTMD3418-82 in the same manner as described above.
  • the average particle size of the (meth) acrylic polymer particles is not particularly limited, but is preferably 50 to 500 nm, for example. When the average particle size is within the above range, it is possible to form irregularities of an appropriate size on the surface of the film while increasing the absorption rate of the laser light, so that slipperiness can be imparted. From the above viewpoint, the average particle size of the (meth) acrylic polymer particles is more preferably 0.07 to 0.28 ⁇ m.
  • the average particle size of the (meth) acrylic polymer particles in the second protective film 13 can be measured by the following method. First, the second protective film 13 is cut, and the obtained cut surface is observed by TEM. Then, the particle diameter is measured for 100 arbitrary particles. The particle size is measured as the equivalent circle diameter of 100 particles obtained by TEM imaging in the same manner as described above. Then, the average value of the obtained particle diameters is defined as the "average particle diameter". In the TEM image, a portion having a brightness of 150% or more of the average brightness of the visual field is determined to be a particle.
  • the content of the light absorbing material is such that the ratio A1 / A2 of the absorption coefficient of the second protective film 13 and the first protective film 12 satisfies the above range, and the absorption coefficient A2 of the second protective film 13 satisfies the above range. Can be set.
  • the mass-based content of the light-absorbing material in the second protective film 13 is preferably higher than the mass-based content of the light-absorbing material in the first protective film 12.
  • the content of the light absorbing material is preferably 0.5 to 10% by mass with respect to the resin.
  • the content of the light absorbing material is in the above range, it is easy to adjust the ratio A1 / A2 of the absorption coefficient to the above range while keeping the absorption coefficient A2 of the second protective film 13 in the above range.
  • the content of the light absorbing material is more preferably 1 to 6% by mass with respect to the resin.
  • the second protective film 13 may further contain other components such as inorganic fine particles, if necessary.
  • the inorganic fine particles have a function of increasing the slipperiness of the second protective film 13.
  • the inorganic material constituting the inorganic fine particles include oxides such as silicon dioxide (SiO 2 ), titanium dioxide, aluminum oxide, and zirconium oxide. Of these, silicon dioxide is preferable because it can reduce the increase in haze of the film.
  • examples of commercially available silicon dioxide particles include Aerosil R812, R972 (manufactured by Nippon Aerosil Co., Ltd.), NanoTek SiO2 (manufactured by CI Kasei Co., Ltd.) and the like.
  • the average primary particle diameter of the inorganic fine particles is preferably 5 to 50 nm.
  • the average primary particle diameter of the inorganic fine particles is more preferably 5 to 30 nm.
  • the average primary particle diameter of the inorganic fine particles in the second protective film 13 can be measured by the same method as described above.
  • the content of the inorganic fine particles is not particularly limited, but may be 0 to 5% by mass, preferably 0 to 2% by mass with respect to the second protective film 13.
  • the total light transmittance of the second protective film 13 is not particularly limited as long as it has sufficient light transmittance, but is preferably 80% or more, more preferably 85% or more, and 88% or more. Is more preferable.
  • the total light transmittance of the second protective film 13 can be measured according to JIS K7361-1: 1997.
  • the total light transmittance of the second protective film 13 can be adjusted by, for example, the content of the light absorbing material.
  • the content of the light absorbing material is preferably set to a certain level or less.
  • the second protective film 13 may have retardation values Ro and Rt depending on its use.
  • the in-plane phase difference Ro measured in an environment where the measurement wavelength of the second protective film 13 is 590 nm and 23 ° C. 55% RH preferably satisfies 40 nm ⁇ Ro ⁇ 60 nm, and the phase difference Rt in the thickness direction. Preferably satisfies 115 nm ⁇ Rt ⁇ 145 nm.
  • Such a second protective film 13 is suitable as a retardation film to be combined with, for example, a VA type liquid crystal cell.
  • the in-plane slow phase axis of the second protective film 13 refers to the axis having the maximum refractive index on the film surface.
  • the in-plane slow-phase axis of the optical film can be confirmed by an automatic birefringence meter Axoscan (AxoScan Mueller Matrix Polarimeter: manufactured by Axometrics).
  • the measurement of Ro and Rt can be performed by the following method. 1) The second protective film 13 is humidity-controlled for 24 hours in an environment of 23 ° C. and 55% RH. The average refractive index of this optical film is measured with an Abbe refractometer, and the thickness d is measured with a commercially available micrometer. 2) The phase difference Ro and Rt of the second protective film 13 after humidity control at a measurement wavelength of 590 nm were measured at 23 ° C. and 55% by using an automatic birefringence meter Axoscan (AxoScan Mueller Matrix Polarimeter: manufactured by Axometrics). Measured in an RH environment.
  • the phase difference Ro and Rt of the second protective film 13 can be adjusted mainly by the draw ratio. In order to increase the phase difference Ro and Rt of the second protective film 13, it is preferable to increase the draw ratio.
  • the thickness of the second protective film 13 is not particularly limited, but is preferably 20 to 70 ⁇ m, more preferably 30 to 45 ⁇ m.
  • the ratio t1 / t2 of the thickness t2 of the second protective film 13 and the thickness t1 of the first protective film 12 is not particularly limited, but may be, for example, 1 to 5.
  • the first protective film 12 and the second protective film 13 may be manufactured by any method, and may be manufactured by, for example, a melt casting method or a solution casting method.
  • a hot melt of a thermoplastic resin composition is cast and then cooled and solidified to obtain a cast film.
  • A1 a step of preparing a thermoplastic resin composition
  • A2) a step of casting a thermal melt of the thermoplastic resin composition and then cooling and solidifying it, and, if necessary, A3) obtained. It can be obtained through a step of stretching a film-like substance.
  • the constituent components of the protective film are dry-blended and then melt-kneaded with a twin-screw extruder or the like to obtain pellets.
  • the prepared pellets of the thermoplastic resin composition are melt-kneaded by a twin-screw extruder or the like, and then cast from a casting die.
  • the thermal melting temperature in the melt casting can be (Tg + 30) to (Tg + 70) ° C., where Tg is the glass transition temperature of the resin.
  • the stretching may be performed according to the required optical characteristics, and it is preferable to stretch in one or more of the width direction (TD direction), the transport direction (MD direction), and the diagonal direction.
  • the draw ratio is set according to the required optical performance, and can be 1.01 to 1.3 times, for example, from the viewpoint of functioning as a low phase difference film.
  • the stretch ratio is defined as (the size of the film after stretching in the stretching direction) / (the size of the film before stretching in the stretching direction).
  • the stretching temperature drying temperature at the time of stretching is preferably (Tg-20) to (Tg + 30) ° C.
  • a solution (dope) in which the constituents of the protective film are dissolved in a solvent is cast and then dried to obtain a casting film.
  • B1 a step of preparing a dope containing a cycloolefin resin, a light absorbing material, and a solvent, and B2) the obtained dope is cast on a support, then dried and peeled to form a cast film. It can be produced through a step of obtaining and, if necessary, a step of stretching the obtained cast film B3).
  • the cycloolefin resin and the light-absorbing material are dissolved or dispersed in a solvent to prepare a dope.
  • the solvent used contains at least an organic solvent (good solvent) capable of dissolving the cycloolefin resin.
  • good solvents include chlorine-based organic solvents such as methylene chloride; non-chlorine-based organic solvents such as methyl acetate, ethyl acetate, acetone and tetrahydrofuran, preferably methylene chloride.
  • the solvent used may further contain a poor solvent such as an aliphatic alcohol having 1 to 4 carbon atoms such as methanol and ethanol from the viewpoint of enhancing the peelability of the cast film from the support.
  • the obtained dope is discharged from, for example, a casting die and spread onto the support.
  • the solvent is then evaporated from the dope cast on the support and then stripped to give a cast film.
  • the obtained flow film is stretched.
  • the stretching ratio and stretching temperature can be the same as in the step of A3) above.
  • the release film 14 is a film that protects the first protective film 12, and is peeled off during use.
  • the type of the release film 14 is not particularly limited as long as it can be peeled off at the time of use.
  • the extinction coefficient of light having a wavelength of 9.4 ⁇ m of the release film 14 is not particularly limited, but is usually higher than that of the second protective film 13 and often equal to or higher than that of the first protective film 12.
  • the release film 14 is, for example, a release film that has been subjected to a mold release treatment, and examples thereof include plastic films such as acrylic films, polycarbonate films, polyester films, and fluororesin films.
  • the thickness of the release film 14 may be any as long as it can protect the first protective film 12, and is not particularly limited, but is preferably, for example, 20 to 60 ⁇ m, and more preferably 30 to 50 ⁇ m.
  • Adhesive layer The adhesive layer (not shown) is arranged between the polarizing element 11 and the first protective film 12 or between the polarizing element 11 and the second protective film 13, and adheres them.
  • the adhesive constituting the adhesive layer is not particularly limited, and may be a dried completely saponified polyvinyl alcohol aqueous solution (water glue) or a cured product of an active energy ray-curable adhesive.
  • the active energy ray-curable adhesive may be any of a photoradical polymerization type composition utilizing photoradical polymerization, a photocationic polymerization type composition utilizing photocationic polymerization, or a combination thereof.
  • the thickness of the adhesive layer can be, for example, 0.01 to 10 ⁇ m, preferably about 0.03 to 5 ⁇ m.
  • the polarizing plate 10 having the above configuration has a cut end face 10a cut by a laser beam (see FIG. 4B). Then, in the cross section of the polarizing plate 11 along the stacking direction L 0 (thickness direction of the polarizing plate 11) (specifically, the cross section along the stacking direction L 0 and orthogonal to the cut end face 10a), the polarizing plate 11 The stacking direction L 0 of the straight line L1 connecting the end point P1 of the cut end surface 10a on the side opposite to the first protective film 12 of the release film 14 and the end point P2 of the polarizing element 11 on the second protective film 15 side.
  • the inclination angle ⁇ with respect to the relative is 0.5 to 10 °.
  • the inclination angle ⁇ is 0.5 ° or more, when the polarizing plate 11 is attached to the display element so that the second protective film 13 side is the display element side and pressed, the inclination of the cut end surface 10a is almost zero. Easy to do. As a result, even if the environmental moist heat changes when the display device is used, light leakage due to the shape of the cut end face 10a of the polarizing plate 10 can be suppressed. From the same viewpoint, the inclination angle ⁇ is more preferably 1 to 10 °, further preferably 6 to 8 °.
  • the cut end face 10a of the polarizing plate 10 can be observed with an optical microscope. Specifically, the inclination angle is measured from an image obtained by observing the cut surface of the sample cut so as to be orthogonal to the cut end surface 10a of the polarizing plate 10 with an optical microscope.
  • FIGS. 5A to 5C are cross-sectional views showing a method for manufacturing a polarizing plate 10 according to the present embodiment.
  • the method for manufacturing the polarizing plate 10 is as follows: 1) A laminate including a polarizing element 11, a first protective film 12, a second protective film 13, and a release film 14. It has a step of preparing 20 (see FIG. 5A) and a step of 2) irradiating the laminated body 20 with laser light from the release film 14 side to cut the laminated body 20 along the stacking direction (thickness direction) (see FIG. 5A). See FIGS. 5B and C).
  • a laminate 20 including a polarizing element 11, a first protective film 12, a second protective film 13, and a release film 14 is prepared (see FIG. 5A).
  • the polarizing element 11 and the first protective film 12 or the second protective film 13 can be bonded by roll-to-roll using the above adhesive.
  • the surface of the obtained laminate 20 (specifically, the surface of the release film 14) is irradiated with laser light to cut the laminate 20 along the lamination direction (FIGS. 5B and 5B). See C).
  • Cutting by laser light is performed by irradiating the laminated body 20 with laser light L from the release film 14 side.
  • the ratio A1 / A2 of the extinction coefficient of the first protective film 12 and the second protective film 13 is appropriately adjusted (the extinction coefficient A2 of the second protective film 13 is appropriately larger than before). ing).
  • the amount of shrinkage of the film on the irradiation side of the laser beam L can be reduced. Therefore, the inclination angle ⁇ of the cut end surface 10a of the polarizing plate 10 after cutting can be made smaller than before (see FIG. 5C).
  • the display device according to the present embodiment includes a display element and a polarizing plate arranged on at least one surface thereof.
  • the type of display element is not particularly limited, and may be an organic EL display element or a liquid crystal display element.
  • the display element is preferably a liquid crystal display element.
  • FIG. 6 is a cross-sectional view showing the configuration of the display device according to the present embodiment.
  • the display device 100 is a first polarizing plate 40 arranged on one surface (for example, the visual recognition side) of the liquid crystal display element 30 (display element) and the liquid crystal display element 30.
  • a second polarizing plate 50 arranged on the other surface (for example, the backlight side) of the liquid crystal display element 30.
  • the liquid crystal display element 30 may have two transparent substrates 31 and 31 and a liquid crystal layer 32 arranged between them.
  • the display mode of the liquid crystal display element 30 is not particularly limited, and is, for example, STN (Super-Twisted Nematic), TN (Twisted Nematic), OCB (Optically Compensated Bend), HAN (Hybridaligned Nematic), VA (Vertical Alignment, MVA (Multi)). -domainVerticalAlignment), PVA (PatternedVerticalAlignment)), IPS (In-Plane-Switching), etc. Above all, the VA mode is preferable.
  • first polarizing plate 40 and the second polarizing plate 50 is the polarizing plate 10 according to the present embodiment.
  • both the first polarizing plate 40 and the second polarizing plate 50 are the polarizing plates 10 according to the present embodiment.
  • the polarizing plate 10 according to the present embodiment is preferably arranged so that the second protective film 13 is on the liquid crystal display element 30 side.
  • the display device configured as described above is manufactured through a step of attaching the polarizing plate 10 according to the present embodiment to at least one surface of the display element.
  • the attachment can be performed by pressing the second protective film 13 of the polarizing plate 10 so as to be on the display element side.
  • the cut end surface 10a of the polarizing plate 10 attached to the liquid crystal display element 30 is substantially parallel to the stacking direction (almost perpendicular to the surface of the liquid crystal display element 30). , Almost not tilted. Therefore, it is possible to suppress display unevenness at the end portion due to the inclination angle of the cut end surface 10a of the polarizing plate 10. Further, such a polarizing plate 10 is compared with a conventional polarizing plate (FIG. 2A) in which the inclination angle ⁇ 0 ° of the cut end surface of the polarizing plate before attachment is large or a polarizing plate having an excessively large ⁇ (FIG. 1A). There is little change in the tilt angle ⁇ due to changes in the moist heat conditions of the usage environment. Therefore, it is possible to further suppress display unevenness at the edges after storage in moist heat.
  • the Tg and Mw of the resin were measured by the following method.
  • Glass transition temperature (Tg) The glass transition temperature of the resin was measured using DSC (Differential Scanning Colorimetry) according to JIS K 7121-2012.
  • the weight average molecular weight (Mw) of the resin was measured using gel permeation chromatography (HLC8220GPC manufactured by Tosoh Corporation) and a column (TSK-GEL G6000HXL-G5000HXL-G5000HXL-G4000HXL-G3000HXL series manufactured by Tosoh Corporation). A sample of 20 ⁇ 0.5 mg was dissolved in 10 ml of tetrahydrofuran and filtered through a 0.45 mm filter. 100 ml of this solution was injected into a column (temperature 40 ° C.), measured at a detector RI temperature of 40 ° C., converted to styrene, and the weight average molecular weight was determined.
  • Light-absorbing material A Light absorbing material B: Methyl methacrylate (MMA) / styrene (St) / ethylene glycol dimethacrylate (EGDMA) (70/10/20 molar ratio) copolymer particles (refractive index 1.51, average particle diameter 0.14 ⁇ m) )
  • MMA Methyl methacrylate
  • St styrene
  • EGDMA ethylene glycol dimethacrylate
  • a dope having the following composition was prepared. First, methylene chloride and ethanol were added to the pressurized dissolution tank. The dried acrylic resin and the above-mentioned light-absorbing material additive liquid (light-absorbing material) were added thereto with stirring, heated, and completely dissolved while stirring. This is referred to as Azumi Filter Paper No. manufactured by Azumi Filter Paper Co., Ltd. Filtration was performed using 244 to prepare a dope.
  • Dichloromethane 300 parts by mass Ethanol: 43 parts by mass PMMA (polymethylmethacrylate): 60 parts by mass
  • the dope was then uniformly cast on the stainless steel belt support at a temperature of 22 ° C. and a width of 1500 mm using an endless belt casting device.
  • the solvent was evaporated on the stainless band support until the residual solvent amount reached 45%, and the solvent was peeled off from the stainless band support while adjusting the peeling speed so that the tension became 162 N / m.
  • the cast film obtained by peeling was stretched by a longitudinal stretching device while evaporating the solvent at 35 ° C.
  • the slits were slit to a width of 1.2 m, and then dried at a temperature of 135 ° C. while being stretched 1.1 times in the width direction with a tenter. Then, the film was wound to obtain a film 101 having a thickness of 40 ⁇ m.
  • Films 102 to 104 were obtained in the same manner as the film 101 except that the type and content of the light absorbing material were changed as shown in Table 1.
  • ⁇ Film 106> Cellulose triacetate (TAC) with a degree of substitution of 2.92 and an average degree of polymerization of 300, 100 parts by mass, ethylphthalyl ethyl glycolate, 2 parts by mass, triphenylphosphate, 10 parts by mass, methylene chloride, 350 parts by mass, ethanol 50.
  • TAC Cellulose triacetate
  • the mass portion was placed in a closed container, the temperature of the mixture was gradually raised while stirring slowly, and the temperature was raised to 45 ° C. over 60 minutes to dissolve.
  • the pressure inside the container was 1.2 atm.
  • This dope was applied to Azumi Filter Paper No. manufactured by Azumi Filter Paper Co., Ltd. After filtering using 244, it was allowed to stand for 24 hours to remove bubbles in the dope.
  • An ultraviolet absorber solution was added in a proportion of 2 parts by mass with respect to 100 parts by mass of the above-mentioned dope, and after sufficiently mixing with a static mixer, the solution was poured from a die onto a stainless steel belt at a dope temperature of 35 ° C. After contacting hot water at a temperature of 35 ° C from the back surface of the stainless belt and drying it on a temperature-controlled stainless belt for 1 minute, contact cold water at 15 ° C with the back surface of the stainless belt and holding it for 15 seconds. It peeled off from the stainless steel belt.
  • the amount of residual solvent in the web at the time of peeling was 70% by mass. Then, the peeled web was dried at 120 ° C. for 10 minutes while fixing both ends to obtain a film 106 having a thickness of 80 ⁇ m.
  • the absorption coefficient A1 of the obtained films 101 to 106 was measured by the following method.
  • Table 1 shows the composition and physical characteristics of the obtained films 101 to 106.
  • the obtained pellets were supplied to an extruder under a nitrogen atmosphere and melt-cast. Then, the melt-extruded film was cooled with a cooling roll, stretched at 160 ° C. and 140%, and peeled off with a peeling roll to obtain a film 201 having a thickness of 40 ⁇ m.
  • a film 202 was obtained in the same manner as the film 201 except that the content of the light absorbing material was changed as shown in Table 2.
  • a film 204 was obtained in the same manner as the film 201 except that the stretching temperature was changed to 180 ° C. and the stretching ratio was changed to 200%.
  • a film 205 was obtained in the same manner as the film 201 except that the type and content of the light absorbing material were changed as shown in Table 2.
  • Films 206 and 208 were obtained in the same manner as in Film 201 except that no light absorbing material was added and the thickness of the film was changed as shown in Table 2 by adjusting the stretching conditions.
  • ⁇ Making film 209> (Preparation of light-absorbing material additive solution) 95 parts by mass of methylene chloride was put into a closed container, and 2.8 parts by mass of the light absorbing material A was added while stirring. Then, the mixture was stirred and mixed with a dissolver for 50 minutes. A light absorbing material dispersion was prepared by passing 2000 g of the obtained mixed solution through a high-pressure disperser (trade name: ultra-high pressure homogenizer M110-E / H, manufactured by Microfluidics Corporation) and treating once at 175 MPa. This was filtered through Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a light absorbing material additive solution.
  • a high-pressure disperser trade name: ultra-high pressure homogenizer M110-E / H, manufactured by Microfluidics Corporation
  • a dope having the following composition was prepared. First, methylene chloride and ethanol were added to the pressurized dissolution tank. COP-A (cycloolefin resin) and the above-mentioned light-absorbing material additive liquid (light-absorbing material) were added thereto with stirring, heated, and completely dissolved while stirring. This is referred to as Azumi Filter Paper No. manufactured by Azumi Filter Paper Co., Ltd. Filtration was performed using 244 to prepare a dope.
  • Dichloromethane 300 parts by mass
  • Ethanol 19 parts by mass
  • COP-B cycloolefin resin
  • the dope was then uniformly cast on the stainless steel belt support at a temperature of 33 ° C. and a width of 1500 mm using an endless belt casting device.
  • the temperature of the stainless steel belt was controlled to 30 ° C.
  • the solvent was evaporated until the amount of the residual solvent in the dope cast on the stainless belt support became 30% by mass, and then the solvent was peeled off from the stainless belt support at a peeling tension of 130 N / m.
  • the cast film obtained by peeling was stretched in the width direction (TD direction) under the condition of 160 ° C. (Tg-10 ° C. of the resin) at a stretch ratio of 50%.
  • the residual solvent at the start of stretching was 10% by mass.
  • the drying zone was dried at 130 ° C. while being conveyed by a large number of rollers. Then, the film was wound to obtain a film 209 having a thickness of 40 ⁇ m.
  • the absorption coefficient A2 of the obtained films 201 to 209 was measured by the same method as described above. Moreover, the average absorption rate of the obtained films 201 to 209 was measured by the following method.
  • Table 2 shows the composition and physical characteristics of the obtained films 201 to 209.
  • the stretched film was washed by immersing it in a 2% by mass potassium iodide aqueous solution at 30 ° C. for several seconds.
  • the obtained stretched film was dried at 90 ° C. to obtain a polarizing element having a thickness of 25 ⁇ m.
  • a polyethylene terephthalate film (PET film) having a thickness of 40 ⁇ m was attached as a release film to one surface of the first protective film in Table 3 with an adhesive.
  • a polarizing element and the second protective film of Table 3 were laminated on the other surface of the first protective film via an acrylic ultraviolet curable adhesive, and bonded to each other to prepare a laminated body.
  • the thickness of the adhesive layer was 1 ⁇ m.
  • the surface of the release film of the obtained laminate was irradiated with a carbon dioxide laser having a wavelength of 9.4 ⁇ m to cut the laminate to obtain a polarizing plate.
  • the cutting conditions were a frequency of 20 kHz, an output of 59 W, and a speed of 60 m / min.
  • the obtained liquid crystal display device was stored in an environment of 60 ° C. and 90 RH% for 500 hours. Then, before storage (initial) and after storage (after moist heat endurance), visually observe in a dark room with the entire screen of the display device displayed in black, and display unevenness (light leakage) at the edge of the display screen. was evaluated.
  • the display unevenness at the edges before storage (initial) and after storage (after moist heat durability) was evaluated according to the following criteria.
  • ⁇ Light leakage is not observed by visual evaluation from an angle of 45 ° from the front as before storage
  • ⁇ Light leakage is slightly observed by visual evaluation from an angle of 45 ° from the front compared to before storage. However, there is no problem.
  • ⁇ Light leakage is observed by visual evaluation from an angle of 45 ° from the front compared to before storage
  • a problematic level ⁇ An angle of 45 ° from the front compared to before storage. Light leakage was remarkably observed in the visual evaluation from the above, and it was judged to be good if the level was above the problematic level.
  • the polarizing plates of Comparative Examples 1 and 3 having a large ratio A1 / A2 of the extinction coefficient between the first protective film and the second protective film have an inclination angle ⁇ of the cut end face of the laser cutting portion of 12 ° or more. It turns out that it is big. Then, it can be seen that the liquid crystal display device using these polarizing plates causes display unevenness at the initial end portion. Further, in the polarizing plate of Comparative Example 2 in which the absorption coefficient A2 of the second protective film exceeds the range of 1.0 ⁇ 10 2 to 4.5 ⁇ 10 2 / ⁇ m, the inclination angle ⁇ of the cut end surface of the laser cut portion is 0.
  • the liquid crystal display devices of Comparative Examples 3 and 4 in which the inclination angle ⁇ of the initial cut end surface of the polarizing plate is extremely large cannot completely suppress the display unevenness both in the initial stage and after the moist heat storage. This is because the inclination angle ⁇ of the initial cut end face is remarkably large beyond 10 °, so that the display unevenness remains in the state, and the force to expand the polarizing element at the time of moisture absorption. It is considered that the force of the protective film to shrink becomes too large.
  • a polarizing plate capable of cutting with laser light without reducing productivity and capable of suppressing display unevenness at the end of the display device, a method for manufacturing the same, and a method for manufacturing the display device. Can be provided.

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