WO2022085726A1 - Polarizing plate, method for manufacturing same, and method for manufacturing display device - Google Patents

Polarizing plate, method for manufacturing same, and method for manufacturing display device 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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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/en
Priority to JP2022557585A priority patent/JPWO2022085726A1/ja
Priority to KR1020237013137A priority patent/KR20230067679A/en
Publication of WO2022085726A1 publication Critical patent/WO2022085726A1/en

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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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Abstract

A polarizing plate according to the present invention is formed by laminating a polarizer, a first protective film disposed on one surface of the polarizer, a second protective film disposed on the other surface of the polarizer, and a release film disposed on a surface of the first protective film on the opposite side to the polarizer. An extinction coefficient A2 of the second protective film for light with a wavelength of 9.4 μm is 1.0×102 to 4.5×102/μm. In a cross-section of the polarizing plate conforming to the lamination direction, a straight line connecting an end point P1 of the release film at a cut end surface on the opposite side to the first protective film and an end point P2 of the polarizer at the cut end surface on the second protective film side has an angle φ of inclination 0.5-10° with respect to the lamination direction.

Description

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A polarizing plate and a method for manufacturing the same, and a method for manufacturing a display device.
　本発明は、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に関する。 The present invention relates to a polarizing plate, a method for manufacturing the same, and a method for manufacturing a display device.
　液晶パネルや有機ＥＬパネルなどの表示パネルは、通常、偏光板を含む。偏光板は、偏光子と、それを挟持する２つの保護フィルム（光学フィルム）とを含む。このような偏光板は、偏光子と２つの保護フィルムとをロールトゥロールで貼り合わせた後、得られる積層体を、表示パネルに適した大きさに切断（切断加工）して製造される。 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.
　積層体の切断加工は、従来は、刃物を用いた切断法が用いられている。しかしながら、刃物による切断加工の場合、切断加工時にフィルム屑などの異物が生じやすい。そのような異物が付着した保護フィルムは、表示パネルに表示欠陥を発生させることがある。 Conventionally, a cutting method using a blade has been used for cutting the laminated body. However, in the case of cutting with a cutting tool, foreign matter such as film scraps is likely to be generated during cutting. A protective film to which such foreign matter adheres may cause display defects on the display panel.
　そこで、近年では、レーザー光を用いて偏光板を切断加工することが行われている（例えば、特許文献１および２参照）。例えば、材質の異なる複数の樹脂層の積層フィルムの切断方法として、樹脂層の種類に応じて、波長の異なるレーザー光を用いて切断する方法が知られている（例えば特許文献１）。また、レーザー光で、途中の深さまで切断した後、物理的に引き裂いて切断する方法などが知られている（例えば特許文献２）。 Therefore, in recent years, the polarizing plate has been cut and processed using laser light (see, for example, Patent Documents 1 and 2). For example, as 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). Further, there is known 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).
特開２０１９－９８４００号公報Japanese Unexamined Patent Publication No. 2019-98400 特開２０１２－３０２４３号公報Japanese Unexamined Patent Publication No. 2012-30243
　ところで、偏光板に用いられる２つの保護フィルムの種類や組み合わせには、種々のものがあり、レーザー光の吸収性も大きく異なることがある。例えば、特許文献１および２では、偏光子の一方の面上にセルローストリアセテートフィルム（ＴＡＣ）、他方の面上にシクロオレフィン樹脂フィルムが積層された積層体を、レーザー光で切断して得られる。しかしながら、そのような偏光板を用いて製造された表示装置は、表示画面の端部に表示ムラを生じやすいという問題があった。 By the way, there are various types and combinations of the two protective films used for the polarizing plate, and the absorption of laser light may differ greatly. For example, in 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. However, 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.
　また、特許文献１の方法では、レーザー光の種類を使い分ける必要があり、特許文献２の方法では、レーザー光による切断法と物理的な切断法とを併用することから、生産性が低いという問題もあった。 Further, in the method of Patent Document 1, it is necessary to use different types of laser light, and in the method of Patent Document 2, since the cutting method by laser light and the physical cutting method are used in combination, there is a problem that productivity is low. There was also.
　本発明は上記事情に鑑みてなされたものであり、生産性を低下させることなく、レーザー光での切断加工が可能であり、かつ表示装置の端部の表示ムラを抑制できる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を提供することを目的とする。 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.
　本発明は、以下の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に関する。 The present invention relates to the following polarizing plate and a method for manufacturing the same, and a method for manufacturing a display device.
　本発明の偏光板は、偏光子と、前記偏光子の一方の面に配置された第１保護フィルムと、前記偏光子の他方の面に配置された第２保護フィルムと、前記第１保護フィルムを挟んで前記偏光子とは反対側の面に配置された剥離フィルムとが積層された偏光板であって、前記第２保護フィルムの、ＡＴＲ法で測定される波長９．４μｍの光の吸光係数Ａ２は、１．０×１０２～４．５×１０２／μｍであり、前記偏光板は、切断端面を有し、前記偏光板の、前記積層方向に沿った断面において、前記切断端面における、前記剥離フィルムの前記第１保護フィルムとは反対側の端点Ｐ１と、前記偏光子の前記第２保護フィルム側の端点Ｐ２とを結んだ直線の、前記積層方向に対する傾斜角度は、０．５～１０°である。 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 μm measured by the ATR method of the second protective film. The coefficient A2 is 1.0 × 10 2 to 4.5 × 10 2 / μm, 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 °.
　本発明の偏光板の製造方法は、偏光子と、前記偏光子の一方の面に配置された第１保護フィルムと、前記偏光子の他方の面に配置された第２保護フィルムと、前記第１保護フィルムの前記偏光子とは反対側の面に配置された剥離フィルムとを含む積層体であって、前記第１保護フィルムの、ＡＴＲ法で測定される波長９．４μｍの光の吸光係数Ａ１と、前記第２保護フィルムの、ＡＴＲ法で測定される波長９．４μｍの光の吸光係数Ａ２との比Ａ１／Ａ２が１～５である積層体を準備する工程と、前記剥離フィルム側から前記積層体にレーザー光を照射して、前記積層体を、前記積層体の積層方向に沿って切断する工程とを有する。 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. 1 A laminate containing a release film arranged on the surface of the protective film opposite to the polarizing element, and the absorption coefficient of light of the first protective film having a wavelength of 9.4 μm measured by the ATR method. A step of preparing a laminate in which the ratio A1 / A2 of A1 to the absorption coefficient A2 of the light having a wavelength of 9.4 μm measured by the ATR method of the second protective film is 1 to 5, and the release film side. It has a step of irradiating the laminated body with a laser beam to cut the laminated body along the laminating direction of the laminated body.
　本発明の表示装置の製造方法は、表示素子の少なくとも一方の面に、本発明の偏光板を、前記第２保護フィルムが前記表示素子側となるように貼り付ける工程を含む。 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.
　本発明によれば、表示装置において光漏れを生じることなく、レーザー光による切断性を高めることができる光学フィルム、偏光板および液晶表示装置を提供することができる。 According to the present invention, it is possible to provide 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.
図１ＡおよびＢは、従来の偏光板を用いた表示装置の製造工程の一部を示す断面図である。1A and 1B are cross-sectional views showing a part of a manufacturing process of a display device using a conventional polarizing plate. 図２ＡおよびＢは、従来の他の偏光板を用いた表示装置の製造工程の一部を示す断面図である。2A and 2B are cross-sectional views showing a part of a manufacturing process of a display device using another conventional polarizing plate. 図３ＡおよびＢは、本実施の形態に係る偏光板を用いた表示装置の製造工程の一部を示す断面図である。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. 図４Ａは、本実施の形態に係る偏光板の構成を示す断面図であり、図４Ｂは、図４Ａの切断面の拡大図である。4A is a cross-sectional view showing the configuration of the polarizing plate according to the present embodiment, and FIG. 4B is an enlarged view of the cut surface of FIG. 4A. 図５Ａ～Ｃは、本実施の形態に係る偏光板の製造工程を示す断面図である。5A to 5C are cross-sectional views showing a manufacturing process of the polarizing plate according to the present embodiment. 図６は、本実施の形態に係る表示装置の構成を示す断面図である。FIG. 6 is a cross-sectional view showing the configuration of the display device according to the present embodiment.
　本発明者らは、レーザー光で切断した従来の偏光板（例えば特許文献１または２の偏光板）を用いた表示装置において、表示画面の端部に表示ムラが生じる原因を検討したところ、レーザー光による切断後の偏光板の切断端面の傾斜角度が関係することを見出した。すなわち、端部の表示ムラを生じるメカニズムは明らかではないが、以下のように推測される。 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.
　図１Ａ～２Ｂは、従来の偏光板を用いた表示装置の製造工程の一部を示す断面図である。図３ＡおよびＢは、本実施の形態に係る偏光板を用いた表示装置の製造工程の一部を示す断面図である。 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.
　（切断端面の傾斜角度φの影響）
　表示装置を作製する際、レーザー光で切断された剥離フィルム付き偏光板Ｐを、表示素子Ｃ上に粘着剤（不図示）などを介して押圧しながら貼り付ける。
　このとき、特許文献１または２のように、偏光子１を挟む２つの保護フィルム２および３のレーザー光の吸収性の差が大きすぎると（具体的には、保護フィルム３のレーザー光の吸収性が保護フィルム２のレーザー光の吸収性よりも極端に低いと）、偏光板Ｐの切断端面に傾斜（表示素子Ｃの表面に近づくにつれて広がるような傾斜（プラス方向の傾斜））が形成されやすい（図１Ａ参照）。このように切断端面が傾斜した偏光板Ｐを表示素子Ｃに押圧しながら貼り付けると、貼り付け後も傾斜が残るため（図１Ｂ参照）、バックライトからの光が屈折される等により表示画面の端部に表示ムラを生じやすい。 (Effect of tilt angle φ of cut end face)
When manufacturing a display device, a polarizing plate P with a release film cut by a laser beam is attached onto a display element C while being pressed via an adhesive (not shown) or the like.
At this time, as in Patent Document 1 or 2, if the difference in laser light absorbency between the two protective films 2 and 3 sandwiching the polarizing element 1 is too large (specifically, the absorption of laser light by the protective film 3). When the property is extremely lower than the absorption of laser light of the protective film 2), an inclination (inclination that expands as it approaches the surface of the display element C (inclination in the plus direction)) is formed on the cut end surface of the polarizing plate P. Easy (see Figure 1A). When the polarizing plate P having an inclined cut end face is attached to the display element C while being pressed, the inclination remains even after the attachment (see FIG. 1B), so that the light from the backlight is refracted and the display screen is displayed. Display unevenness is likely to occur at the edges of the.
　一方、切断端面が傾斜していない偏光板Ｐを表示素子Ｃに押圧しながら貼り付けると（図２Ａ参照）、貼り付け後には、偏光板Ｐの切断端面が上記と逆方向（マイナス方向）に傾斜しやすい（図２Ｂ参照）。そのため、上記と同様に、表示画面の端部に表示ムラを生じやすい。 On the other hand, when the polarizing plate P whose cut end surface is not inclined is attached while being pressed against the display element C (see FIG. 2A), the cut end surface of the polarizing plate P is attached in the opposite direction (minus direction) to the above after the attachment. Easy to tilt (see FIG. 2B). Therefore, similarly to the above, display unevenness is likely to occur at the edge of the display screen.
　これに対して本発明では、表示素子Ｃへ貼り付ける前の偏光板１０の切断端面の傾斜を緩やかにする（図３Ａ参照）。具体的には、各フィルムの積層方向に沿った断面において、偏光板１０の切断端面の傾斜角度を０．５～１０°に調整する（後述する図４Ｂ参照）。それにより、表示素子Ｃへ貼り付けた後の偏光板の切断端面の傾斜角度をほぼ０°に近づけることができる（表示素子Ｃの表面に対してほぼ垂直にできる）ため（図３Ｂ参照）、切断端面の傾斜角度（形状）に起因する表示画面の端部の表示ムラを抑制できる。 On the other hand, in the present invention, 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.
　（レーザー切断に起因する内部応力の影響）
　また、図２Ａのような従来の偏光板（傾斜角度φ＝０°）では、保護フィルムに切断による内部応力がほとんど残留していない。そのため、吸湿などにより偏光子が膨張しようとする際に、保護フィルムが収縮しようとする力がほとんど生じないため、偏光板の切断端面の傾斜角度φが、（切断端面の）表示素子Ｃとの接点を起点として上記マイナス方向に大きくなりやすい（湿度変化による傾斜角度φの変化量が大きい）。一方で、図１Ａのような偏光板（φが過大）では、保護フィルムにレーザー切断による大きな内部応力が残留している。そのため、吸湿などにより偏光子が膨張しようとする力に対して保護フィルムが収縮しようとする力が大きくなりすぎて、上記プラス方向に傾斜角度φが変化しやすい。
　これに対し、図３Ａのような本発明の偏光板では、保護フィルムにレーザー切断による内部応力が適度に残留している。そのため、吸湿などにより偏光子が膨張しようとする力を打ち消す方向に収縮しようとする力が適度に生じやすく、表示素子Ｃとの接点を中心として上記マイナス方向にも上記プラス方向にも大きくなりにくい（湿度変化による傾斜角度φの変化量が少ない）。それにより、湿熱耐久後の光学ムラもさらに低減できる。 (Effect of internal stress caused by laser cutting)
Further, in the conventional polarizing plate (tilt angle φ = 0 °) as shown in FIG. 2A, almost no internal stress due to cutting remains in the protective film. Therefore, when the polarizing element tries to expand due to moisture absorption or the like, almost no force is generated to shrink the protective film, so that the inclination angle φ of the cut end face of the polarizing plate is different from that of the display element C (of the cut end face). It tends to increase in the above-mentioned negative direction starting from the contact point (the amount of change in the tilt angle φ due to humidity change is large). On the other hand, in the polarizing plate (φ is excessive) as shown in FIG. 1A, a large internal stress due to laser cutting remains in the protective film. Therefore, the force that the protective film tends to shrink becomes too large with respect to the force that the polarizing element tends to expand due to moisture absorption or the like, and the inclination angle φ tends to change in the positive direction.
On the other hand, in the polarizing plate of the present invention as shown in FIG. 3A, the internal stress due to laser cutting remains moderately on the protective film. Therefore, a force that tends to contract in a direction that cancels the force that the polarizing element tends to expand due to moisture absorption or the like is likely to be appropriately generated, and it is difficult to increase in the negative direction or the positive direction centering on the contact point with the display element C. (The amount of change in the tilt angle φ due to changes in humidity is small). As a result, the optical unevenness after the endurance of moist heat can be further reduced.
　偏光板１０の切断端面の傾斜角度は、任意の方法で調整することができる。中でも、偏光板１０の切断端面の傾斜角度は、第１保護フィルム１２および第２保護フィルム１３のレーザー光の吸光性やそれらの比によって調整することが好ましい。具体的には、第１保護フィルム１２および第２保護フィルム１３のレーザー光の吸光性の比を適度に小さくすること；すなわち、第２保護フィルム１３の波長９．４μｍの光の吸光係数を適度に大きくし（１．０×１０２～４．５×１０２／μｍとし）、かつ第１保護フィルム１２の吸光係数Ａ１と第２保護フィルム１３の吸光係数Ａ２との比Ａ１／Ａ２を適度に小さくすることが好ましい。以下、本発明の構成について説明する。 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 μm 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 / μm). It is preferable to make it small. Hereinafter, the configuration of the present invention will be described.
　１．偏光板
　図４Ａは、本実施の形態に係る偏光板１０の構成を示す断面図であり、図４Ｂは、図４Ａの切断面の拡大図である。なお、図４ＡおよびＢでは、接着層の図示を省略している。 1. 1. Polarizer FIG. 4A is a cross-sectional view showing the configuration of the polarizing plate 10 according to the present embodiment, and FIG. 4B is an enlarged view of the cut surface of FIG. 4A. In FIGS. 4A and 4B, the illustration of the adhesive layer is omitted.
　図４ＡおよびＢに示されるように、本実施の形態に係る偏光板１０は、偏光子１１、その一方の面に配置された第１保護フィルム１２、他方の面に配置された第２保護フィルム１３、および、第１保護フィルム１２を介して偏光子１１と反対側の面に配置された剥離フィルム１４を含む。なお、偏光子１１と第１保護フィルム１２または第２保護フィルム１３との間には、それぞれ接着層（不図示）が配置されている。 As shown in FIGS. 4A and 4B, the polarizing plate 10 according to the present embodiment 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.
　１－１．偏光子１１
　偏光子１１は、一定方向の偏波面の光だけを通す素子であり、ポリビニルアルコール系偏光フィルムである。ポリビニルアルコール系偏光フィルムには、ポリビニルアルコール系フィルムにヨウ素を染色させたものと、二色性染料を染色させたものとがある。 1-1. Polarizer 11
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.
　ポリビニルアルコール系偏光フィルムは、ポリビニルアルコール系フィルムを一軸延伸した後、ヨウ素または二色性染料で染色したフィルム（好ましくはさらにホウ素化合物で耐久性処理を施したフィルム）であってもよいし；ポリビニルアルコール系フィルムをヨウ素または二色性染料で染色した後、一軸延伸したフィルム（好ましくは、さらにホウ素化合物で耐久性処理を施したフィルム）であってもよい。偏光子の吸収軸は、最大延伸方向と平行である。 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.
　偏光子１１の厚みは、５～４０μｍであることが好ましく、偏光板を薄型化するため等から、５～３０μｍであることがより好ましい。 The thickness of the polarizing element 11 is preferably 5 to 40 μm, and more preferably 5 to 30 μm in order to reduce the thickness of the polarizing plate.
　１－２．第１保護フィルム１２
　第１保護フィルム１２は、偏光子１１の一方の面上、具体的には偏光子１１と剥離フィルム１４との間に配置されている。第１保護フィルム１２は、表示装置にしたときに、偏光子１１を介して表示素子とは反対側（表示素子から離れている側）に配置される。 1-2. 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.
　第１保護フィルム１２を構成する樹脂は、特に制限されず、透明性を有し、かつ第１保護フィルム１２と第２保護フィルム１３の吸光係数の比Ａ１／Ａ２が一定以下となるような樹脂であればよい。そのような樹脂の例には、ポリエステル樹脂、（メタ）アクリル樹脂、セルロースエステル樹脂（ＴＡＣフィルムなど）、シクロオレフィン樹脂などが含まれる。中でも、第１保護フィルムは、（メタ）アクリル樹脂またはシクロオレフィン樹脂を含むことが好ましい。 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.
　（（メタ）アクリル樹脂）
　（メタ）アクリル樹脂は、メチルメタクリレートに由来する構造単位を含む重合体であることが好ましい。当該重合体は、メチルメタクリレートと共重合可能なモノマーに由来する構造単位をさらに含んでもよい。メチルメタクリレートと共重合可能な他のモノマーの例には、２－エチルヘキシルメタクリレートなどのメチルメタクリレート以外の炭素原子数１～１８のアルキル（メタ）アクリレート；（メタ）アクリル酸などのα，β－不飽和酸；マレイン酸、フマル酸、イタコン酸などの不飽和ジカルボン酸；スチレン、α－メチルスチレンなどのスチレン類；無水マレイン酸；マレイミド、Ｎ－フェニルマレイミドなどのマレイミド類；グルタル酸無水物などが含まれる。 ((Meta) acrylic 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; α, β-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 α-methylstyrene; maleic anhydride; maleimides such as maleimide and N-phenylmaleimide; included.
　上記共重合体を構成する全構造単位に対する、メタクリル酸メチル由来の構造単位の含有割合は、５０質量％以上であることが好ましく、７０質量％以上であることがより好ましい。 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.
　（シクロオレフィン樹脂）
　シクロオレフィン樹脂は、後述する第２保護フィルム１３に含まれるシクロオレフィン樹脂と同様のものを使用することができる。すなわち、第１保護フィルムに含まれるシクロオレフィン樹脂の組成は、第２保護フィルムに含まれるシクロオレフィン樹脂の組成と同じであってもよいし、異なってもよい。 (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.
　（メタ）アクリル樹脂およびシクロオレフィン樹脂の重量平均分子量は、後述するシクロオレフィン樹脂の重量平均分子量と同様の範囲としうる。 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.
　（厚み）
　第１保護フィルム１２の厚みは、特に制限されないが２０～７０μｍであることが好ましく、３０～６０μｍであることがより好ましい。 (Thickness)
The thickness of the first protective film 12 is not particularly limited, but is preferably 20 to 70 μm, and more preferably 30 to 60 μm.
　１－３．第２保護フィルム１３
　第２保護フィルム１３は、偏光子１１の他方の面に配置されている。具体的には、第２保護フィルム１３は、表示装置にしたときに、表示素子と偏光子１１との間（偏光子１１よりも表示素子に近い側）に配置される。 1-3. 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.
　第２保護フィルム１３の材料は、第１保護フィルム１２と第２保護フィルム１３の吸光係数の比Ａ１／Ａ２が、１～５となるものであることが好ましい。Ａ１／Ａ２が１以上であると、より短時間で偏光板の切断がしやすい。一方、Ａ１／Ａ２が５以下であると、第２保護フィルム１３が適度なレーザー光の吸収性を有するため（第２保護フィルム１３のレーザー光の吸収性が第１保護フィルム１２に対して低すぎないため）、切断による収縮量を少なくしうる。それにより、得られる偏光板１０の切断端面１０ａの傾斜角度も小さくしやすい。同様の観点から、吸光係数の比Ａ１／Ａ２は、１．５～５．０であることが好ましく、２．０～４．５であることがより好ましい。 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. When A1 / A2 is 1 or more, it is easy to cut the polarizing plate in a shorter time. On the other hand, when A1 / A2 is 5 or less, 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. From the same viewpoint, the ratio A1 / A2 of the absorption coefficient is preferably 1.5 to 5.0, more preferably 2.0 to 4.5.
　第２保護フィルム１３の波長９．４μｍの光の吸光係数Ａ２は、上記の通り、１．０×１０２～４．５×１０２／μｍであることが好ましい。吸光係数Ａ２が１．０×１０２／μｍ以上であると、レーザー光を適度に吸収しうるため、レーザー光による切断性を高めることができる。第２保護フィルム１３の吸光係数Ａ２は、透明性が損なわれにくく、かつ表示装置における光漏れを生じにくくする観点では、１．５×１０２～４．０×１０２／μｍであることがより好ましく、２．０×１０２～３．５×１０２／μｍであることがより好ましい。 As described above, the extinction coefficient A2 of the light having a wavelength of 9.4 μm of the second protective film 13 is preferably 1.0 × 10 2 to 4.5 × 10 2 / μm. When the absorption coefficient A2 is 1.0 × 10 2 / μm 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 / μm 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 / μm.
　第１保護フィルム１２の吸光係数Ａ１および第２保護フィルム１３の吸光係数Ａ２は、それぞれ以下の方法で測定することができる。
　顕微ＦＴＩＲ（Ａｇｉｌｅｎｔ製「ＵＭＡ６００」および「ＦＴＳ３０００」）を用いてＡＴＲ法（全反射測定法；Attenuated Total Reflection）にて、入射光径：１００μｍ、プリズム：Ｇｅ（入射角４５°）、検出器：ＭＣＴ－Ａ、分解能：４．０ｃｍ－１、積算：６４回の条件で、赤外吸収スペクトルを測定した。得られた赤外吸収スペクトルから、波長９．４μｍに相当する部分（周波数１０４１ｃｍ－１）の吸光度を読み取る。そして、下記式に基づいて、フィルムの吸光係数を求めることができる。
　吸光係数（／μｍ）＝吸光度×ｌｏｇｅ１０／フィルムの厚み（μｍ）
　フィルムの吸光係数は、主に、フィルムの組成によって調整することができる。 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.
By ATR method (Attenuated Total Reflection) using microscopic FTIR (Agient's "UMA600" and "FTS3000"), incident light diameter: 100 μm, 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 μm is read. Then, the extinction coefficient of the film can be obtained based on the following formula.
Absorption coefficient (/ μm) = Absorbance x loge10 / Film thickness (μm)
The extinction coefficient of the film can be adjusted mainly by the composition of the film.
　第２保護フィルム１３の組成は、上記の吸収特性を満たすものであればよく、特に制限されないが、シクロオレフィン樹脂を含むことが好ましく、光吸収材料をさらに含むことがより好ましい。すなわち、第２保護フィルム１３は、シクロオレフィン樹脂と、光吸収材料とを含むことが好ましい。 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.
　１－３－１．シクロオレフィン樹脂
　シクロオレフィン樹脂は、ノルボルネン系単量体に由来する構造単位を含む重合体である。ノルボルネン系単量体は、下記式（１）で表される。
Figure JPOXMLDOC01-appb-C000001
 1-3-1. Cycloolefin resin Cycloolefin resin is a polymer containing structural units derived from norbornene-based monomers. The norbornene-based monomer is represented by the following formula (1).
Figure JPOXMLDOC01-appb-C000001
　式（１）のＲ１～Ｒ４は、それぞれ水素原子、ハロゲン原子、炭化水素基、または極性基を表す。 R 1 to R 4 of the formula (1) represent a hydrogen atom, a halogen atom, a hydrocarbon group, or a polar group, respectively.
　ハロゲン原子の例には、フッ素原子、塩素原子などが含まれる。 Examples of halogen atoms include fluorine atoms and chlorine atoms.
　炭化水素基は、炭素原子数が１～１０、好ましくは１～４、より好ましくは１または２の炭化水素基である。炭化水素基の例には、メチル基、エチル基、プロピル基、ブチル基などのアルキル基が含まれる。炭化水素基は、酸素原子、窒素原子、硫黄原子またはケイ素原子を含む連結基（例えばカルボニル基、イミノ基、エーテル結合、シリルエーテル結合、チオエーテル結合など）の２価の連結基をさらに有していてもよい。 The hydrocarbon group is a hydrocarbon group having 1 to 10, preferably 1 to 4, more preferably 1 or 2 carbon atoms. Examples of 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.
　極性基の例には、カルボキシ基、ヒドロキシ基、アルコキシ基、アルコキシカルボニル基、アリロキシカルボニル基、アミノ基、アミド基、およびメチレン基などの連結基（－（ＣＨ２）ｎ－、ｎは１以上の整数）を介してこれらの基が結合した基が含まれる。中でも、アルコキシカルボニル基およびアリールオキシカルボニル基が好ましく、アルコキシカルボニル基がより好ましい。 Examples of 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. Of these, an alkoxycarbonyl group and an aryloxycarbonyl group are preferable, and an alkoxycarbonyl group is more preferable.
　中でも、Ｒ１～Ｒ４のうち少なくとも１つは、極性基であることが好ましい。極性基を有するノルボルネン系単量体に由来する構造単位を含むシクロオレフィン樹脂は、例えば溶液流延法で製膜する際に、溶剤に溶解させやすく、得られるフィルムのガラス転移温度も高めやすいためである。一方、溶融製膜法では、極性基を有するノルボルネン系単量体に由来する構造単位を含まないシクロオレフィン樹脂であってよい。 Above all, it is preferable that at least one of 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. On the other hand, in the melt film forming method, a cycloolefin resin containing no structural unit derived from a norbornene-based monomer having a polar group may be used.
　また、Ｒ１～Ｒ４のうち、Ｒ１およびＲ２の両方（またはＲ３およびＲ４の両方）は、水素原子であってもよい。 Further, among R 1 to R 4 , both R 1 and R 2 (or both R 3 and R 4 ) may be hydrogen atoms.
　式（１）のｐは、０～２の整数を示す。第２保護フィルムの耐熱性を高める観点では、ｐは、１～２であることが好ましい。 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.
　式（１）で表されるノルボルネン系単量体の具体例を、以下に示す。このうち、極性基を有するノルボルネン系単量体の例には、以下のものが含まれる。 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.
Figure JPOXMLDOC01-appb-C000002
Figure JPOXMLDOC01-appb-C000002
　極性基を有しないノルボルネン系単量体の例には、以下のものが含まれる。
Figure JPOXMLDOC01-appb-C000003
 Examples of norbornene-based monomers having no polar group include:
Figure JPOXMLDOC01-appb-C000003
　ノルボルネン系単量体に由来する構造単位の含有量は、シクロオレフィン樹脂を構成する全構造単位に対して５０～１００モル％でありうる。 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.
　シクロオレフィン樹脂は、ノルボルネン系単量体に由来する構造単位と共重合可能な他の単量体に由来する構造単位をさらに含んでいてもよい。共重合可能な他の単量体の例には、（上記ノルボルネン系単量体が極性基を有する場合は）極性基を有しないノルボルネン系単量体や、シクロブテン、シクロペンテン、シクロヘプテン、シクロオクテン、ジシクロペンタジエンなどのノルボルネン骨格を有しないシクロオレフィン系単量体などが含まれる。 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.
　シクロオレフィン樹脂としては、市販品を用いてもよい。市販品の例には、ＪＳＲ社製のアートン（ＡＲＴＯＮ：登録商標）Ｇ、アートンＦ、アートンＲ、およびアートンＲＸが含まれる。 As the 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.
　シクロオレフィン樹脂の重量平均分子量Ｍｗは、特に制限されないが、２万～３０万であることが好ましく、３万～２５万であることがより好ましく、４万～２０万であることがさらに好ましい。シクロオレフィン樹脂の重量平均分子量Ｍｗが上記範囲にあると、成形加工性を損なうことなく、第２保護フィルム１３の機械的特性を高めうる。 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. When 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.
　シクロオレフィン樹脂の重量平均分子量Ｍｗは、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）により測定することができる。
　具体的には、測定装置としては、ゲル浸透クロマトグラフィー（東ソー社製ＨＬＣ８２２０ＧＰＣ）、カラムとしては、東ソー社製 ＴＳＫ－ＧＥＬ Ｇ６０００ＨＸＬ－Ｇ５０００ＨＸＬ－Ｇ５０００ＨＸＬ－Ｇ４０００ＨＸＬ－Ｇ３０００ＨＸＬ直列を用いる。
　そして、試料２０±０．５ｍｇをテトラヒドロフラン１０ｍｌに溶解し、０．４５ｍｍのフィルターで濾過する。この溶液を上記カラム（温度４０℃）に１００ｍｌ注入し、検出器ＲＩ、温度４０℃で測定し、スチレン換算して、重量平均分子量を求める。 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.
　シクロオレフィン樹脂のガラス転移温度Ｔｇは、通常、１１０℃以上であることが好ましく、１１０～３５０℃であることがより好ましく、１２０～２５０℃であることがより好ましい。シクロオレフィン樹脂のＴｇが１１０℃以上であると、高温条件下でも変形が起こりにくい。Ｔｇが３５０℃以下であると、成形加工性が損なわれにくく、成形加工時のシクロオレフィン樹脂の熱劣化をより抑制しうる。 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. When the Tg of the cycloolefin resin is 110 ° C. or higher, deformation is unlikely to occur even under high temperature conditions. When 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.
　ガラス転移温度は、ＤＳＣ（Ｄｉｆｆｅｒｅｎｔｉａｌ Ｓｃａｎｎｉｎｇ Ｃｏｌｏｒｉｍｅｔｒｙ：示差走査熱量法）を用いて、ＪＩＳ Ｋ ７１２１－２０１２に準拠した方法で測定することができる。 The glass transition temperature can be measured by a method compliant with JIS K7121-2012 using DSC (Differential Scanning Colorimetry).
　シクロオレフィン樹脂の含有量は、特に制限されないが、第２保護フィルム１３に対して５０質量％以上であることが好ましく、７０～９９質量％であることがより好ましい。 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.
　１－３－２．光吸収材料
　光吸収材料は、通常、カルボニル基を有する化合物であることが好ましく、エステル化合物または（メタ）アクリル重合体粒子であることがより好ましい。 1-3-2. Light Absorbent Material The light absorption material is usually preferably a compound having a carbonyl group, more preferably an ester compound or (meth) acrylic polymer particles.
　＜エステル化合物＞
　エステル化合物は、糖エステル化合物、重縮合エステル化合物、多価アルコールエステル化合物のいずれであってもよい。 <Ester compound>
The ester compound may be any of a sugar ester compound, a polycondensation ester compound, and a polyhydric alcohol ester compound.
　（糖エステル化合物）
　糖エステル化合物は、単糖、二糖または三糖のＯＨ基の全部または一部をエステル化した化合物である。そのような糖エステル化合物は、下記式（ＦＡ）で表される化合物であることが好ましい。
Figure JPOXMLDOC01-appb-C000004
 (Sugar ester compound)
Glycoester compounds are compounds in which all or part of the OH groups of monosaccharides, disaccharides or trisaccharides are esterified. Such a sugar ester compound is preferably a compound represented by the following formula (FA).
Figure JPOXMLDOC01-appb-C000004
　式（ＦＡ）のＲ１～Ｒ８は、置換もしくは無置換のアルキルカルボニル基、または置換もしくは無置換のアリールカルボニル基を表わす。Ｒ１～Ｒ８は、互いに同じであっても、異なってもよい。 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.
　置換もしくは無置換のアルキルカルボニル基は、炭素原子数２以上の置換もしくは無置換のアルキルカルボニル基であることが好ましい。置換もしくは無置換のアルキルカルボニル基の例には、メチルカルボニル基（アセチル基）、エチルカルボニル基などが含まれる。アルキル基が有する置換基の例には、フェニル基などのアリール基が含まれる。 The substituted or unsubstituted alkylcarbonyl group is preferably a substituted or unsubstituted alkylcarbonyl group having 2 or more carbon atoms. Examples of substituted or unsubstituted alkylcarbonyl groups include methylcarbonyl groups (acetyl groups), ethylcarbonyl groups and the like. Examples of substituents contained in alkyl groups include aryl groups such as phenyl groups.
　置換もしくは無置換のアリールカルボニル基は、炭素原子数７以上の置換もしくは無置換のアリールカルボニル基であることが好ましい。アリールカルボニル基の例には、フェニルカルボニル基が含まれる。アリール基が有する置換基の例には、メチル基などのアルキル基が含まれる。 The substituted or unsubstituted arylcarbonyl group is preferably a substituted or unsubstituted arylcarbonyl group having 7 or more carbon atoms. Examples of arylcarbonyl groups include phenylcarbonyl groups. Examples of substituents contained in aryl groups include alkyl groups such as methyl groups.
　式（ＦＡ）のＲ１～Ｒ８の例には、以下のものが含まれる。
Figure JPOXMLDOC01-appb-C000005
 Examples of formulas (FA) R 1 to R 8 include:
Figure JPOXMLDOC01-appb-C000005
　糖エステル化合物の平均置換度は、３～６であることが好ましい。糖エステル化合物の平均置換度は、原料となる糖のＯＨ基の総数のうちエステル化された平均割合を示す。 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.
　（多価アルコールエステル化合物）
　多価アルコールエステルは、２価以上の脂肪族多価アルコール（好ましくは２～２０価の脂肪族多価アルコール）とモノカルボン酸とのエステル化物である。 (Multivalent alcohol ester compound)
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.
　多価アルコールの例には、アドニトール、アラビトール、エチレングリコール、ジエチレングリコール、トリエチレングリコール、テトラエチレングリコール、１，２－プロパンジオール、１，３－プロパンジオール、ジプロピレングリコール、トリプロピレングリコール、１，２－ブタンジオール、１，３－ブタンジオール、１，４－ブタンジオール、ジブチレングリコール、１，２，４－ブタントリオール、１，５－ペンタンジオール、１，６－ヘキサンジオール、ヘキサントリオール、ガラクチトール、マンニトール、３－メチルペンタン－１，３，５－トリオール、ピナコール、ソルビトール、トリメチロールプロパン、トリメチロールエタン、キシリトールなどが含まれ、好ましくはトリエチレングリコール、テトラエチレングリコール、ジプロピレングリコール、トリプロピレングリコール、ソルビトール、トリメチロールプロパン、キシリトールである。 Examples of polyhydric alcohols include adonitol, arabitol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2. -Butanediol, 1,3-butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, galactitol , Mannitol, 3-methylpentane-1,3,5-triol, pinacol, sorbitol, trimethylolpropane, trimethylolethane, xylitol and the like, preferably triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene and the like. Glycol, sorbitol, trimethylolpropane, xylitol.
　モノカルボン酸は、特に制限されず、酢酸、プロピオン酸などの脂肪族モノカルボン酸、シクロペンタンカルボン酸、シクロヘキサンカルボン酸などの脂環族モノカルボン酸、安息香酸、トルイル酸などの芳香族モノカルボン酸のいずれであってもよい。 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.
　多価アルコールエステル化合物に用いられるカルボン酸は１種類でもよいし、２種以上の混合であってもよい。また、多価アルコール中のＯＨ基は、全てエステル化してもよいし、一部をＯＨ基として残っていてもよい。 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.
　糖エステル化合物および多価アルコールエステル化合物の分子量は、第２保護フィルムの製造方法にもよるが、シクロオレフィン樹脂との良好な相溶性を得られやすくする観点では、適度に低いことが好ましい。具体的には、糖エステル化合物やエステル化合物の分子量は、例えば３００～１５００、好ましくは６００～１２００としうる。 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. Specifically, the molecular weight of the sugar ester compound or the ester compound can be, for example, 300 to 1500, preferably 600 to 1200.
　（重縮合エステル化合物）
　重縮合エステル化合物は、ジカルボン酸とジオールを反応させて得られる構造単位を含む重縮合体（重合体）である。 (Polycondensation ester compound)
The polycondensation ester compound is a polycondensate (polymer) containing a structural unit obtained by reacting a dicarboxylic acid with a diol.
　ジカルボン酸は、芳香族ジカルボン酸、脂肪族ジカルボン酸、脂環式ジカルボン酸のいずれであってもよく、好ましくは芳香族ジカルボン酸である。ジカルボン酸は、１種類であっても、２種類以上の混合物であってもよい。芳香族ジカルボン酸と脂肪族ジカルボン酸とを混合することが好ましい。 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.
　ジオールは、芳香族ジオール、脂肪族ジオール、脂環式ジオールのいずれであってもよく、好ましくは脂肪族ジオール、より好ましくは炭素原子数１～４のジオールである。ジオールは、１種類であっても、２種類以上の混合物であってもよい。 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.
　すなわち、重縮合エステル化合物は、芳香族ジカルボン酸を含むジカルボン酸と、炭素原子数１～８のジオールとを反応させて得られる構造単位を含むことが好ましく、芳香族ジカルボン酸と脂肪族ジカルボン酸とを含むジカルボン酸と、炭素原子数１～８のジオールとを反応させて得られる構造単位を含むことがより好ましい。重縮合エステルの分子の両末端は、封止されていても、封止されていなくてもよい。 That is, 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.
　これらのエステル化合物のうち、分子量が適度に低く、シクロオレフィン樹脂との相溶性に優れる点では、糖エステル化合物が特に好ましい。 Among these ester compounds, the sugar ester compound is particularly preferable in that the molecular weight is moderately low and the compatibility with the cycloolefin resin is excellent.
　＜（メタ）アクリル重合体粒子＞
　（メタ）アクリル重合体粒子は、（メタ）アクリレート類に由来する構造単位を含む重合体の粒子であり、好ましくはメチルメタクリレートに由来する構造単位を含む重合体の粒子である。 <(Meta) acrylic polymer particles>
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.
　メチルメタクリレートに由来する構造単位を含む重合体は、他の共重合モノマーに由来する構造単位をさらに含んでもよい。他の共重合モノマーの例には、メタクリル酸メチル以外の炭素原子数１～１８のアルキル（メタ）アクリレート；（メタ）アクリル酸などのα，β－不飽和酸；マレイン酸、フマル酸、イタコン酸などの不飽和ジカルボン酸；スチレン、α－メチルスチレンなどのスチレン類；（ポリ）エチレングリコールジ（メタ）アクリレート、ブタンジオールジ（メタ）アクリレート、エチレングリコールジ（メタ）アクリレート、トリエチレングリコールジ（メタ）アクリレート、テトラエチレングリコールジ（メタ）アクリレートなどの（メタ）アクリル基を２個以上有する多官能（メタ）アクリル酸エステル類；アリル（メタ）アクリレート、アリルアルキル（メタ）アクリレートなどのアリルアルキル（メタ）アクリレート類などの多官能モノマー類などが含まれる。 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; α, β-unsaturated acids such as (meth) acrylic acid; maleic acid, fumaric acid, and itacon. Unsaturated dicarboxylic acids such as acids; styrenes such as styrene and α-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.
　中でも、上記重合体は、架橋重合体であること、すなわち、メチルメタクリレートに由来する構造単位と、多官能モノマーに由来する構造単位とを含む共重合体であることが好ましく；メチルメタクリレートに由来する構造単位と、スチレン類に由来する構造単位と、多官能モノマー類に由来する構造単位とを含む共重合体であることがより好ましい。 Above all, 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.
　第２保護フィルム１３のレーザー光の吸収率を高める観点では、カルボニル基を含む（メタ）アクリレート類に由来する構造単位の含有量が一定以上であることが好ましい。そのような観点から、メチルメタクリレートに由来する構造単位の合計は、重合体を構成する全構造単位に対して３０モル％以上であることが好ましく、５０～８０モル％であることがより好ましい。 From the viewpoint of increasing the absorption rate of the laser light of the second protective film 13, it is preferable that the content of the structural unit derived from the (meth) acrylates containing a carbonyl group is a certain level or more. From such a viewpoint, 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.
　多官能性モノマー由来の構造単位の含有量は、重合体を構成する全構造単位の合計に対して３～５０モル％であることが好ましく、１０～３５モル％であることがより好ましい。 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.
　（メタ）アクリル重合体粒子は、シクロオレフィン樹脂との屈折率差が０．０１以下の重合体であることが好ましい。そのような（メタ）アクリル重合体粒子は、得られる第２保護フィルムの透明性を低下させにくい。 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.
　シクロオレフィン樹脂と（メタ）アクリル重合体粒子の屈折率は、それぞれ波長５５０ｎｍの光の屈折率でありうる。波長５５０ｎｍの光の屈折率は、例えば、各成分を単独で含むサンプルフィルムを作製し、当該サンプルフィルムの波長５５０ｎｍの光の屈折率を、堀場製分光エリプソメーターＵＶＳＥＬを用いて測定することにより求めることができる。 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.
　（メタ）アクリル重合体粒子のＴｇは、８０℃以上であることが好ましい。（メタ）アクリル重合体粒子のＴｇは、上記と同様に、ＪＩＳＫ ７１２１－２０１２またはＡＳＴＭＤ ３４１８－８２に準拠して測定することができる。 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.
　（メタ）アクリル重合体粒子の平均粒子径は、特に制限されないが、例えば５０～５００ｎｍであることが好ましい。平均粒子径が上記範囲内であると、レーザー光の吸収率を高めつつ、フィルムの表面に適度な大きさの凹凸を形成しうるため、滑り性を付与しうる。（メタ）アクリル重合体粒子の平均粒子径は、上記観点から、０．０７～０．２８μｍであることがより好ましい。 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 μm.
　第２保護フィルム１３における（メタ）アクリル重合体粒子の平均粒子径は、以下の方法で測定することができる。まず、第２保護フィルム１３を切断し、得られる切断面をＴＥＭ観察する。そして、任意の粒子１００個の粒子について、粒子径を測定する。粒子径は、前述と同様に、ＴＥＭ撮影によって得た粒子１００個の円相当径として測定する。そして、得られた粒子径の平均値を「平均粒子径」とする。なお、ＴＥＭ画像において、明度が視野の平均明度×１５０％以上の部分を、粒子と判断する。 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.
　光吸収材料の含有量は、第２保護フィルム１３と第１保護フィルム１２の吸光係数の比Ａ１／Ａ２が上記範囲を満たし、かつ第２保護フィルム１３の吸光係数Ａ２が上記範囲を満たすように設定されうる。 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.
　例えば、第２保護フィルム１３における光吸収材料の質量基準の含有量は、第１保護フィルム１２における光吸収材料の質量基準の含有量よりも多いことが好ましい。 For example, 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.
　具体的には、光吸収材料の含有量は、樹脂に対して０．５～１０質量％であることが好ましい。光吸収材料の含有量が上記範囲であると、第２保護フィルム１３の吸光係数Ａ２を上記範囲にしつつ、吸光係数の比Ａ１／Ａ２を上記範囲に調整しやすい。それにより、第２保護フィルム１３のレーザー光による切断性を適度に高めつつ、得られる偏光板１０の切断端面１０ａの傾斜角度を上記範囲に調整しやすい。同様の観点から、光吸収材料の含有量は、樹脂に対して１～６質量％であることがより好ましい。 Specifically, the content of the light absorbing material is preferably 0.5 to 10% by mass with respect to the resin. When 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. As a result, it is easy to adjust the inclination angle of the cut end surface 10a of the obtained polarizing plate 10 within the above range while appropriately improving the cutability of the second protective film 13 by the laser beam. From the same viewpoint, the content of the light absorbing material is more preferably 1 to 6% by mass with respect to the resin.
　１－３－３．他の成分
　第２保護フィルム１３は、必要に応じて無機微粒子などの他の成分をさらに含んでいてもよい。 1-3-3. Other components The second protective film 13 may further contain other components such as inorganic fine particles, if necessary.
　無機微粒子は、第２保護フィルム１３の滑り性を高める機能を有する。無機微粒子を構成する無機材料の例には、二酸化珪素（ＳｉＯ２）、二酸化チタン、酸化アルミニウム、酸化ジルコニウムなどの酸化物が含まれる。中でも、フィルムのヘイズの増大を少なくしうる点などから、二酸化ケイ素が好ましい。二酸化ケイ素粒子の市販品の例には、アエロジルＲ８１２、Ｒ９７２（日本アエロジル社製）、ＮａｎｏＴｅｋ ＳｉＯ２（シーアイ化成社製）などが含まれる。 The inorganic fine particles have a function of increasing the slipperiness of the second protective film 13. Examples of 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.
　無機微粒子の平均一次粒子径は、５～５０ｎｍであることが好ましい。無機微粒子の平均一次粒子径が５ｎｍ以上であると、フィルムの表面を粗面化することができるので、滑り性を付与しやすく、５０ｎｍ以下であると、ヘイズの増大を抑制しやすい。無機微粒子の平均一次粒子径は、５～３０ｎｍであることがより好ましい。第２保護フィルム１３における無機微粒子の平均一次粒子径は、上記と同様の方法で測定することができる。 The average primary particle diameter of the inorganic fine particles is preferably 5 to 50 nm. When the average primary particle diameter of the inorganic fine particles is 5 nm or more, the surface of the film can be roughened, so that slipperiness is easily imparted, and when it is 50 nm or less, an increase in haze is likely to be suppressed. 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.
　無機微粒子の含有量は、特に制限されないが、第２保護フィルム１３に対して０～５質量％、好ましくは０～２質量％としうる。 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.
　１－３－４．物性
　（全光線透過率）
　第２保護フィルム１３の全光線透過率は、十分な光透過性を有していれば特に制限されないが、８０％以上であることが好ましく、８５％以上であることがより好ましく、８８％以上であることがさらに好ましい。第２保護フィルム１３の全光線透過率は、ＪＩＳ　Ｋ７３６１－１：１９９７に準拠して測定することができる。 1-3-4. Physical characteristics (total light transmittance)
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.
　第２保護フィルム１３の全光線透過率は、例えば光吸収材料の含有量などによって調整されうる。第２保護フィルム１３の全光線透過率を高くするためには、例えば光吸収材料の含有量を一定以下とすることが好ましい。 The total light transmittance of the second protective film 13 can be adjusted by, for example, the content of the light absorbing material. In order to increase the total light transmittance of the second protective film 13, for example, the content of the light absorbing material is preferably set to a certain level or less.
　（位相差ＲｏおよびＲｔ）
　第２保護フィルム１３は、その用途に応じた位相差値ＲｏおよびＲｔを有しうる。例えば、第２保護フィルム１３の測定波長５９０ｎｍ、２３℃５５％ＲＨの環境下で測定される面内方向の位相差Ｒｏは、４０ｎｍ≦Ｒｏ≦６０ｎｍを満たすことが好ましく、厚み方向の位相差Ｒｔは、１１５ｎｍ≦Ｒｔ≦１４５ｎｍを満たすことが好ましい。そのような第２保護フィルム１３は、例えばＶＡ方式の液晶セルと組み合わされる位相差フィルムとして好適である。 (Phase difference Ro and Rt)
The second protective film 13 may have retardation values Ro and Rt depending on its use. For example, 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.
　ＲｏおよびＲｔは、それぞれ下記式で定義される。
　式（２ａ）：Ｒｏ＝（ｎｘ－ｎｙ）×ｄ
　式（２ｂ）：Ｒｔ＝（（ｎｘ＋ｎｙ）／２－ｎｚ）×ｄ
　（式中、
　ｎｘは、第２保護フィルム１３の面内遅相軸方向（屈折率が最大となる方向）の屈折率を表し、
　ｎｙは、第２保護フィルム１３の面内遅相軸に直交する方向の屈折率を表し、
　ｎｚは、第２保護フィルム１３の厚み方向の屈折率を表し、
　ｄは、第２保護フィルム１３の厚み（ｎｍ）を表す。） Ro and Rt are defined by the following equations, respectively.
Equation (2a): Ro = (nx-ny) × d
Equation (2b): Rt = ((nx + ny) /2-nz) × d
(During the ceremony,
nx represents the refractive index of the second protective film 13 in the in-plane slow phase axial direction (direction in which the refractive index is maximized).
ny represents the refractive index in the direction orthogonal to the in-plane slow phase axis of the second protective film 13.
nz represents the refractive index of the second protective film 13 in the thickness direction.
d represents the thickness (nm) of the second protective film 13. )
　第２保護フィルム１３の面内遅相軸とは、フィルム面において屈折率が最大となる軸をいう。光学フィルムの面内遅相軸は、自動複屈折率計アクソスキャン（ＡｘｏＳｃａｎＭｕｅｌｌｅｒ Ｍａｔｒｉｘ Ｐｏｌａｒｉｍｅｔｅｒ：アクソメトリックス社製）により確認することができる。 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).
　ＲｏおよびＲｔの測定は、以下の方法で行うことができる。
　１）第２保護フィルム１３を２３℃５５％ＲＨの環境下で２４時間調湿する。この光学フィルムの平均屈折率をアッベ屈折計で測定し、厚みｄを市販のマイクロメーターを用いて測定する。
　２）調湿後の第２保護フィルム１３の、測定波長５９０ｎｍにおける位相差Ｒｏ及びＲｔを、それぞれ自動複屈折率計アクソスキャン（ＡｘｏＳｃａｎＭｕｅｌｌｅｒ Ｍａｔｒｉｘ Ｐｏｌａｒｉｍｅｔｅｒ：アクソメトリックス社製）を用いて、２３℃５５％ＲＨの環境下で測定する。 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.
　第２保護フィルム１３の位相差ＲｏおよびＲｔは、主として延伸倍率によって調整することができる。第２保護フィルム１３の位相差ＲｏおよびＲｔを高くするためには、延伸倍率を高くすることが好ましい。 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.
　（厚み）
　第２保護フィルム１３の厚みは、特に制限されないが、２０～７０μｍであることが好ましく、３０～４５μｍであることがより好ましい。また、第２保護フィルム１３の厚みｔ２と第１保護フィルム１２の厚みｔ１の比ｔ１／ｔ２は、特に制限されないが、例えば１～５でありうる。 (Thickness)
The thickness of the second protective film 13 is not particularly limited, but is preferably 20 to 70 μm, more preferably 30 to 45 μm. 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.
　１－３－５．製造方法
　第１保護フィルム１２および第２保護フィルム１３は、任意の方法で製造されてよく、例えば溶融流延法または溶液流延法で製造されうる。 1-3-5. Manufacturing Method 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.
　溶融流延法では、熱可塑性樹脂組成物の熱溶融物を流延した後、冷却固化させて、流延膜を得る。具体的には、Ａ１）熱可塑性樹脂組成物を準備する工程、Ａ２）熱可塑性樹脂組成物の熱溶融物を流延した後、冷却固化する工程、および、必要に応じてＡ３）得られた膜状物を延伸する工程を経て得ることができる。 In the melt casting method, a hot melt of a thermoplastic resin composition is cast and then cooled and solidified to obtain a cast film. Specifically, 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.
　Ａ１）の工程では、保護フィルムの構成成分をドライブレンド後、二軸押出機などで溶融混練して、ペレットを得る。 In the step A1), 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.
　Ａ２）の工程では、準備した熱可塑性樹脂組成物のペレットを、それぞれ二軸押出機などで溶融混練した後、流延ダイから流延させる。溶融流延における熱溶融温度は、樹脂のガラス転移温度をＴｇとしたとき、（Ｔｇ＋３０）～（Ｔｇ＋７０）℃としうる。 In the step A2), 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.
　Ａ３）の工程では、延伸は、求められる光学特性に応じて行えばよく、幅方向（ＴＤ方向）、搬送方向（ＭＤ方向）、斜め方向のうち一以上の方向に延伸することが好ましい。 In the step A3), 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.
　延伸倍率は、求められる光学性能に応じて設定され、例えば低位相差のフィルムとして機能させる観点では、１．０１～１．３倍とすることができる。延伸倍率は、（延伸後のフィルムの延伸方向大きさ）／（延伸前のフィルムの延伸方向大きさ）として定義される。延伸温度（延伸時の乾燥温度）は、（Ｔｇ－２０）～（Ｔｇ＋３０）℃であることが好ましい。 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.
　（溶液流延法）
　溶液流延法では、保護フィルムの構成成分を溶剤に溶解させた溶液（ドープ）を流延した後、乾燥させて、流延膜を得る。具体的には、Ｂ１）シクロオレフィン樹脂、光吸収材料、および溶剤を含むドープを準備する工程、Ｂ２）得られたドープを支持体上に流延した後、乾燥および剥離して流延膜を得る工程、および必要に応じてＢ３）得られた流延膜を延伸する工程を経て製造されうる。 (Solution casting method)
In the solution casting method, 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. Specifically, 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).
　Ｂ１）の工程では、シクロオレフィン樹脂および光吸収材料を、溶媒に溶解または分散させて、ドープを調製する。用いられる溶媒は、少なくともシクロオレフィン樹脂を溶解させうる有機溶媒（良溶媒）を含む。良溶媒の例には、メチレンクロライドなどの塩素系有機溶媒や；酢酸メチル、酢酸エチル、アセトン、テトラヒドロフランなどの非塩素系有機溶媒が含まれ、好ましくはメチレンクロライドである。用いられる溶媒は、流延膜の支持体からの剥離性を高める観点などから、メタノール、エタノールなどの炭素原子数１～４の脂肪族アルコールなどの貧溶媒をさらに含んでいてもよい。 In the step B1), 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. Examples of 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.
　Ｂ２）の工程では、得られたドープを、例えば流延ダイから吐出させて、支持体上に流延する。次いで、支持体上に流延されたドープから溶媒を蒸発させた後、剥離して流延膜を得る。 In the step B2), 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.
　Ｂ３）の工程では、得られた流延膜を延伸する。延伸倍率や延伸温度は、上記Ａ３）の工程と同様としうる。 In the step B3), the obtained flow film is stretched. The stretching ratio and stretching temperature can be the same as in the step of A3) above.
　１－４．剥離フィルム１４
　剥離フィルム１４は、第１保護フィルム１２を保護するフィルムであり、使用時には剥離される。 1-4. Release film 14
The release film 14 is a film that protects the first protective film 12, and is peeled off during use.
　剥離フィルム１４の種類は、特に制限されず、使用時に剥離可能なものであればよい。剥離フィルム１４の波長９．４μｍの光の吸光係数は、特に制限されないが、通常、第２保護フィルム１３よりは高く、かつ第１保護フィルム１２と同程度か、それよりも高いことが多い。剥離フィルム１４は、例えば離型処理が施された剥離フィルムであり、その例には、アクリルフィルム、ポリカーボネートフィルム、ポリエステルフィルム、フッ素樹脂フィルムなどのプラスチックフィルムが含まれる。 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 μm 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.
　（厚み）
　剥離フィルム１４の厚みは、第１保護フィルム１２を保護できるものであればよく、特に制限されないが、例えば２０～６０μｍであることが好ましく、３０～５０μｍであることがより好ましい。 (Thickness)
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 μm, and more preferably 30 to 50 μm.
　１－５．接着層
　接着層（不図示）は、偏光子１１と第１保護フィルム１２との間、または、偏光子１１と第２保護フィルム１３との間に配置されており、それらを接着させる。 1-5. 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.
　接着層を構成する接着剤は、特に制限されず、完全ケン化型ポリビニルアルコール水溶液（水糊）を乾燥させたものであるか、または、活性エネルギー線硬化性接着剤の硬化物でありうる。活性エネルギー線硬化性接着剤は、光ラジカル重合を利用した光ラジカル重合型組成物、光カチオン重合を利用した光カチオン重合型組成物、またはそれらの併用物のいずれであってもよい。 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.
　接着層の厚みは、例えば０．０１～１０μｍ、好ましくは０．０３～５μｍ程度でありうる。 The thickness of the adhesive layer can be, for example, 0.01 to 10 μm, preferably about 0.03 to 5 μm.
　１－６．物性
　（傾斜角度）
　上記のような構成を有する偏光板１０は、レーザー光で切断された切断端面１０ａを有する（図４Ｂ参照）。そして、上記積層方向Ｌ０（偏光板１１の厚み方向）に沿った偏光板１１の断面（具体的には、積層方向Ｌ０に沿い、かつ切断端面１０ａと直交する断面）において、偏光板１１の切断端面１０ａの、剥離フィルム１４の第１保護フィルム１２とは反対側の端点Ｐ１と、偏光子１１の第２保護フィルム１５側の端点Ｐ２とを結んだ直線Ｌ１の、積層方向Ｌ０に対する傾斜角度φが０．５～１０°である。傾斜角度φが０．５°以上であると、偏光板１１を、第２保護フィルム１３側が表示素子側となるように表示素子に貼り付けて押圧した際に、切断端面１０ａの傾斜をほぼゼロにしやすい。それにより、表示装置にしたときに、環境湿熱が変化しても、偏光板１０の切断端面１０ａの形状に起因する光漏れを抑制できる。同様の観点から、上記傾斜角度φは、１～１０°であることがより好ましく、６～８°であることがさらに好ましい。 1-6. Physical characteristics (tilt angle)
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 φ with respect to the relative is 0.5 to 10 °. When the inclination angle φ 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 φ is more preferably 1 to 10 °, further preferably 6 to 8 °.
　偏光板１０の切断端面１０ａの観察は、光学顕微鏡により行うことができる。具体的には、偏光板１０の切断端面１０ａと直交するように切断したサンプルの切断面を、光学顕微鏡により観察して得られる画像から傾斜角度を測定する。 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.
　２．偏光板の製造方法
　図５Ａ～Ｃは、本実施の形態に係る偏光板１０の製造方法を示す断面図である。 2. 2. Method for manufacturing a polarizing plate FIGS. 5A to 5C are cross-sectional views showing a method for manufacturing a polarizing plate 10 according to the present embodiment.
　図５Ａ～Ｃに示されるように、本実施の形態に係る偏光板１０の製造方法は、１）偏光子１１、第１保護フィルム１２、第２保護フィルム１３、および剥離フィルム１４を含む積層体２０を準備する工程（図５Ａ参照）、および２）剥離フィルム１４側から積層体２０にレーザー光を照射して、積層体２０を積層方向（厚み方向）に沿って切断する工程とを有する（図５ＢおよびＣ参照）。 As shown in FIGS. 5A to 5C, the method for manufacturing the polarizing plate 10 according to the present embodiment 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).
　１）の工程について
　まず、偏光子１１、第１保護フィルム１２、第２保護フィルム１３、および剥離フィルム１４を含む積層体２０を準備する（図５Ａ参照）。 Regarding the step 1), first, 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).
　偏光子１１と第１保護フィルム１２または第２保護フィルム１３との貼り合わせは、上記接着剤を用いて、ロールトゥロールで行うことができる。 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.
　２）の工程について
　次いで、得られた積層体２０の表面（具体的には剥離フィルム１４の表面）にレーザー光を照射して、積層体２０を、積層方向に沿って切断する（図５ＢおよびＣ参照）。 Regarding the step 2) Next, 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).
　レーザー光による切断は、レーザー光Ｌを、剥離フィルム１４側から積層体２０に照射して行う。本実施の形態では、第１保護フィルム１２と第２保護フィルム１３の吸光係数の比Ａ１／Ａ２が適切に調整されている（従来よりも第２保護フィルム１３の吸光係数Ａ２が適度に大きくなっている）。それにより、切断時に過剰なエネルギーを要しないため、レーザー光Ｌの照射側のフィルム（特に第１保護フィルム１２）の収縮量を少なくすることができる。そのため、切断後の偏光板１０の切断端面１０ａの傾斜角度φを、従来よりも小さくすることができる（図５Ｃ参照）。 Cutting by laser light is performed by irradiating the laminated body 20 with laser light L from the release film 14 side. In the present embodiment, 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). As a result, since excessive energy is not required at the time of cutting, the amount of shrinkage of the film on the irradiation side of the laser beam L (particularly, the first protective film 12) can be reduced. Therefore, the inclination angle φ of the cut end surface 10a of the polarizing plate 10 after cutting can be made smaller than before (see FIG. 5C).
　３．表示装置およびその製造方法
　本実施の形態に係る表示装置は、表示素子、およびその少なくとも一方の面上に配置された偏光板を有する。 3. 3. Display device and method for manufacturing the display device The display device according to the present embodiment includes a display element and a polarizing plate arranged on at least one surface thereof.
　表示素子の種類は、特に限定されず、有機ＥＬ表示素子や液晶表示素子でありうる。本実施の形態では、表示素子は、液晶表示素子であることが好ましい。 The type of display element is not particularly limited, and may be an organic EL display element or a liquid crystal display element. In the present embodiment, the display element is preferably a liquid crystal display element.
　図６は、本実施の形態に係る表示装置の構成を示す断面図である。 FIG. 6 is a cross-sectional view showing the configuration of the display device according to the present embodiment.
　図６に示されるように、本実施の形態に係る表示装置１００は、液晶表示素子３０（表示素子）、液晶表示素子３０の一方の面（例えば視認側）に配置された第１偏光板４０、および液晶表示素子３０の他方の面（例えばバックライト側）に配置された第２偏光板５０を含む。 As shown in FIG. 6, the display device 100 according to the present embodiment 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. , And a second polarizing plate 50 arranged on the other surface (for example, the backlight side) of the liquid crystal display element 30.
　液晶表示素子３０は、２つの透明基板３１および３１と、それらの間に配置された液晶層３２とを有しうる。液晶表示素子３０の表示モードは、特に制限されず、例えばＳＴＮ（Super-Twisted Nematic）、ＴＮ（Twisted Nematic）、ＯＣＢ（Optically Compensated Bend）、ＨＡＮ（Hybridaligned Nematic）、ＶＡ（Vertical Alignment、ＭＶＡ（Multi-domain Vertical Alignment）、ＰＶＡ（Patterned Vertical Alignment））、ＩＰＳ（In-Plane-Switching）などでありうる。中でも、ＶＡモードが好ましい。 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.
　第１偏光板４０および第２偏光板５０のうち一方または両方は、本実施の形態に係る偏光板１０である。本実施の形態では、第１偏光板４０および第２偏光板５０の両方が、本実施の形態に係る偏光板１０である。本実施の形態に係る偏光板１０は、第２保護フィルム１３が液晶表示素子３０側となるように配置されることが好ましい。 One or both of the first polarizing plate 40 and the second polarizing plate 50 is the polarizing plate 10 according to the present embodiment. In 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.
　このように構成された表示装置は、表示素子の少なくとも一方の面に、本実施の形態に係る偏光板１０を貼り付ける工程を経て製造される。貼り付けは、偏光板１０の第２保護フィルム１３が、表示素子側となるように押圧して行うことができる。 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.
　本実施の形態に係る表示装置１００では、液晶表示素子３０に貼り付けられた偏光板１０の切断端面１０ａは、上記積層方向とほぼ平行（液晶表示素子３０の表面に対してほぼ垂直）であり、ほとんど傾斜していない。そのため、偏光板１０の切断端面１０ａの傾斜角度に起因する端部の表示ムラを抑制できる。また、そのような偏光板１０は、貼り付け前の偏光板の切断端面の傾斜角度φ≒０°である従来の偏光板（図２Ａ）やφが大きすぎる偏光板（図１Ａ）と比べて、使用環境の湿熱条件の変化による傾斜角度φの変化も少ない。そのため、湿熱保存後の端部の表示ムラもさらに抑制できる。 In the display device 100 according to the present embodiment, 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 φ≈0 ° of the cut end surface of the polarizing plate before attachment is large or a polarizing plate having an excessively large φ (FIG. 1A). There is little change in the tilt angle φ 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.
　以下、実施例により本発明を具体的に説明するが、本発明はこれらに限定されるものではない。 Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto.
　１．第１保護フィルムおよび第２保護フィルムの材料
　（１）樹脂
　シクロオレフィン樹脂Ａ（ＣＯＰ－Ａ、Ｔｇ：１６２℃、Ｍｗ：１０００００、エチレン：単位１：単位２＝５０：２８：２２モル比）
Figure JPOXMLDOC01-appb-C000006
 　シクロオレフィン樹脂Ｂ（ＣＯＰ－Ｂ、Ｔｇ：１７０℃、Ｍｗ：１０００００）
Figure JPOXMLDOC01-appb-C000007
 　（メタ）アクリル樹脂（Ａｃｒ）：ポリメチルメタクリレート（ＰＭＭＡ、Ｔｇ：１１０℃、Ｍｗ：３０００００） 1. 1. Materials for the first protective film and the second protective film (1) Resin Cycloolefin resin A (COP-A, Tg: 162 ° C., Mw: 100,000, ethylene: unit 1: unit 2 = 50: 28: 22 molar ratio)
Figure JPOXMLDOC01-appb-C000006
 Cycloolefin resin B (COP-B, Tg: 170 ° C., Mw: 100,000)
Figure JPOXMLDOC01-appb-C000007
 (Meta) Acrylic resin (Acr): Polymethylmethacrylate (PMMA, Tg: 110 ° C., Mw: 300,000)
　樹脂のＴｇおよびＭｗは、以下の方法で測定した。 The Tg and Mw of the resin were measured by the following method.
　［ガラス転移温度（Ｔｇ）］
　樹脂のガラス転移温度を、ＤＳＣ（Ｄｉｆｆｅｒｅｎｔｉａｌ Ｓｃａｎｎｉｎｇ Ｃｏｌｏｒｉｍｅｔｒｙ：示差走査熱量法）を用いて、ＪＩＳ Ｋ ７１２１－２０１２に準拠して測定した。 [Glass transition temperature (Tg)]
The glass transition temperature of the resin was measured using DSC (Differential Scanning Colorimetry) according to JIS K 7121-2012.
　［重量平均分子量（Ｍｗ）］
　樹脂の重量平均分子量（Ｍｗ）を、ゲル浸透クロマトグラフィー（東ソー社製ＨＬＣ８２２０ＧＰＣ）、カラム（東ソー社製 ＴＳＫ－ＧＥＬ  Ｇ６０００ＨＸＬ－Ｇ５０００ＨＸＬ－Ｇ５０００ＨＸＬ－Ｇ４０００ＨＸＬ－Ｇ３０００ＨＸＬ  直列）を用いて測定した。試料２０±０．５ｍｇをテトラヒドロフラン１０ｍｌに溶解し、０．４５ｍｍのフィルターで濾過した。この溶液をカラム（温度４０℃）に１００ｍｌ注入し、検出器ＲＩ温度４０℃で測定し、スチレン換算して、重量平均分子量を求めた。 [Weight average molecular weight (Mw)]
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.
　（２）光吸収材料
　光吸収材料Ａ：
Figure JPOXMLDOC01-appb-C000008
 　光吸収材料Ｂ：メタクリル酸メチル（ＭＭＡ）／スチレン（Ｓｔ）／エチレングリコールジメタクリレート（ＥＧＤＭＡ）（７０／１０／２０モル比）共重合体粒子（屈折率１．５１、平均粒子径０．１４μｍ） (2) Light-absorbing material Light-absorbing material A:
Figure JPOXMLDOC01-appb-C000008
 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 μm) )
　２．第１保護フィルムの作製または準備
　＜フィルム１０１の作製＞
　（光吸収材料添加液の調製）
　メチレンクロライド９５質量部を密閉容器に投入し、撹拌しながら光吸収材料Ａを４．５質量部加えた。その後、ディゾルバーで５０分間撹拌混合した。得られた混合液２０００ｇを、高圧分散装置（商品名：超高圧ホモジナイザーＭ１１０－Ｅ／Ｈ、Ｍｉｃｒｏｆｌｕｉｄｉｃｓ　Ｃｏｒｐｏｒａｔｉｏｎ　製）に通し、１７５ＭＰａで１回処理することで、光吸収材料分散液を調製した。これを、日本精線（株）製のファインメットＮＦで濾過し、光吸収材料添加液を調製した。 2. 2. Preparation or preparation of the first protective film <Production of film 101>
(Preparation of light-absorbing material additive solution)
95 parts by mass of methylene chloride was put into a closed container, and 4.5 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.
　（ドープの調製）
　下記組成のドープを調製した。まず、加圧溶解タンクにメチレンクロライドとエタノールを添加した。これに、乾燥したアクリル樹脂と、上記光吸収材料添加液（光吸収材料）を撹拌しながら投入し、加熱し、撹拌しながら、完全に溶解させた。これを、安積濾紙（株）製の安積濾紙Ｎｏ．２４４を使用して濾過し、ドープを調製した。
　ジクロロメタン：３００質量部
　エタノール：４３質量部
　ＰＭＭＡ（ポリメチルメタクリレート）：６０質量部
　光吸収材料添加液（光吸収材料Ａ）：６０質量部 (Preparation of dope)
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 Light absorption material additive liquid (light absorption material A): 60 parts by mass
　（製膜）
　次いで、無端ベルト流延装置を用い、ドープを、温度２２℃、１５００ｍｍ幅でステンレスベルト支持体上に均一に流延した。ステンレスバンド支持体上で、残留溶剤量が４５％になるまで溶媒を蒸発させ、張力が１６２Ｎ／ｍとなるように剥離速度を調整しながらステンレスバンド支持体上から剥離した。剥離して得られた流延膜を、３５℃で溶媒を蒸発させながら縦延伸装置で延伸した。１．２ｍ幅にスリットし、その後、テンターで幅方向に１．１倍に延伸しながら、１３５℃の温度で乾燥させた。その後巻き取り、厚み４０μｍのフィルム１０１を得た。 (Film formation)
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 μm.
　＜フィルム１０２～１０４の作製＞
　光吸収材料の種類および含有量を表１に示されるように変更した以外はフィルム１０１と同様にしてフィルム１０２～１０４を得た。 <Manufacturing of films 102 to 104>
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.
　＜フィルム１０５＞
　東洋紡株式会社コスモシャイン（登録商標） <Film 105>
Toyobo Co., Ltd. Cosmo Shine (registered trademark)
　＜フィルム１０６＞
　アセチル基の置換度２．９２、粘度平均重合度３００のセルローストリアセテート（ＴＡＣ）１００質量部、エチルフタリルエチルグリコレート２質量部、トリフェニルフォスフェイト１０質量部、塩化メチレン３５０質量部、エタノール５０質量部を密閉容器に入れ、混合物をゆっくり攪拌しながら徐々に昇温し、６０分かけて４５℃まで上げ溶解した。容器内は１．２気圧となった。このドープを安積濾紙（株）製の安積濾紙Ｎｏ．２４４を使用して濾過した後、２４時間静置しドープ中の泡を除いた。 <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. 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.
　また、これとは別に、上記セルローストリアセテート５質量部、チヌビン３２６（ＢＡＳＦジャパン（株）製）３質量部、チヌビン１０９（ＢＡＳＦジャパン（株）製）７質量部、チヌビン１７１（ＢＡＳＦジャパン（株）製）５質量部、及びＡＥＲＯＳＩＬ　２００Ｖ（日本アエロジル（株）製）１質量部を塩化メチレン９０質量部とエタノール１０質量部を混合し撹拌溶解し、紫外線吸収剤溶液を調製した。上記ドープ１００質量部に対して紫外線吸収剤溶液を２質量部の割合で加え、スタチックミキサーにより十分混合した後、ダイからステンレスベルト上にドープ温度３５℃で流延した。ステンレスベルトの裏面から３５℃の温度の温水を接触させて温度制御されたステンレスベルト上で１分間乾燥した後、更にステンレスベルトの裏面に、１５℃の冷水を接触させて１５秒間保持した後、ステンレスベルトから剥離した。 Separately from this, 5 parts by mass of the above cellulose triacetate, 3 parts by mass of tinubin 326 (manufactured by BASF Japan Ltd.), 7 parts by mass of tinubin 109 (manufactured by BASF Japan Ltd.), and tinubin 171 (manufactured by BASF Japan Ltd.). 5 parts by mass of AEROSIL and 1 part by mass of AEROSIL (manufactured by Nippon Aerosil Co., Ltd.) were mixed with 90 parts by mass of methylene chloride and 10 parts by mass of ethanol and dissolved by stirring to prepare an ultraviolet absorber solution. 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.
　剥離時のウェブ中の残留溶媒量は７０質量％であった。次いで剥離したウェブの両端を固定しながら１２０℃で１０分間乾燥させ、厚み８０μｍのフィルム１０６を得た。 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 μm.
　得られたフィルム１０１～１０６の吸光係数Ａ１を、以下の方法で測定した。 The absorption coefficient A1 of the obtained films 101 to 106 was measured by the following method.
　［吸光係数］
　得られたフィルムについて、顕微ＦＴＩＲ（Ａｇｉｌｅｎｔ製「ＵＭＡ６００」および「ＦＴＳ３０００」）を用いてＡＴＲ法にて、入射光径：１００μｍ、プリズム：Ｇｅ（入射角４５°）、検出器：ＭＣＴ－Ａ、分解能：４．０ｃｍ－１、積算：６４回の条件で、赤外吸収スペクトルを測定した。得られた赤外吸収スペクトルから、波長９．４μｍに相当する部分（周波数１０４１ｃｍ－１）の吸光度を読み取った。そして、下記式に基づいて、フィルムの吸光係数を求めた。
　吸光係数（／μｍ）＝吸光度×ｌｏｇ１０／フィルムの厚み（μｍ） [Absorption coefficient]
With respect to the obtained film, an incident light diameter: 100 μm, a prism: Ge (incident angle 45 °), a detector: MCT-A, by ATR method using a microscopic FTIR (“UMA600” and “FTS3000” manufactured by Agilent). The infrared absorption spectrum was measured under the conditions of resolution: 4.0 cm -1 and 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 μm was read. Then, the extinction coefficient of the film was determined based on the following formula.
Absorption coefficient (/ μm) = Absorbance x log10 / Film thickness (μm)
　得られたフィルム１０１～１０６の組成および物性を、表１に示す。 Table 1 shows the composition and physical characteristics of the obtained films 101 to 106.
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000009
　３．第２保護フィルムの作製
　＜フィルム２０１の作製＞
　（ペレットの調製）
　光吸収材料Ａの含有量がＣＯＰ－Ａに対して２．８質量％となるように、ＣＯＰ－Ａと光吸収材料Ａとを、真空ナウターミキサーで混合し、乾燥した後、２軸式押し出し機を用いて溶融し、樹脂混合物のペレットを得た。 3. 3. Preparation of second protective film <Production of film 201>
(Preparation of pellets)
COP-A and light absorbing material A are mixed with a vacuum nouter mixer and dried so that the content of the light absorbing material A is 2.8% by mass with respect to COP-A. It was melted using an extruder to obtain pellets of the resin mixture.
　（流延）
　得られたペレットを、窒素雰囲気下で押出し機に供給し、溶融流延した。そして、溶融押出したフィルムを、冷却ロールで冷却した後、１６０℃１４０％で延伸し、剥離ロールで剥離し、厚み４０μｍのフィルム２０１を得た。 (Hypersalivation)
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 μm.
　＜フィルム２０２の作製＞
　光吸収材料の含有量を表２に示されるように変更した以外はフィルム２０１と同様にしてフィルム２０２を得た。 <Manufacturing of film 202>
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.
　＜フィルム２０３および２０７の作製＞
　ＣＯＰ－Ａ：１００質量部を、ＣＯＰ－Ａ：５０質量部とＣＯＰ－Ｂ：５０質量部の混合物に変更し、かつ光吸収材料の含有量を表２に示されるように変更した以外はフィルム２０１と同様にしてフィルム２０３および２０７を得た。 <Manufacturing of films 203 and 207>
Film except that COP-A: 100 parts by mass was changed to a mixture of COP-A: 50 parts by mass and COP-B: 50 parts by mass, and the content of the light absorbing material was changed as shown in Table 2. Films 203 and 207 were obtained in the same manner as in 201.
　＜フィルム２０４の作製＞
　延伸温度を１８０℃、延伸倍率を２００％に変更した以外はフィルム２０１と同様にしてフィルム２０４を得た。 <Manufacturing of film 204>
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%.
　＜フィルム２０５＞
　光吸収材料の種類および含有量を表２に示されるように変更した以外はフィルム２０１と同様にしてフィルム２０５を得た。 <Film 205>
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.
　＜フィルム２０６および２０８の作製＞
　光吸収材料を添加せず、かつ延伸条件を調整してフィルムの厚みを表２に示されるように変更した以外はフィルム２０１と同様にしてフィルム２０６および２０８を得た。 <Manufacturing of films 206 and 208>
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.
　＜フィルム２０９の作製＞
　（光吸収材料添加液の調製）
　メチレンクロライド９５質量部を密閉容器に投入し、撹拌しながら光吸収材料Ａを２．８質量部加えた。その後、ディゾルバーで５０分間撹拌混合した。得られた混合液２０００ｇを、高圧分散装置（商品名：超高圧ホモジナイザーＭ１１０－Ｅ／Ｈ、Ｍｉｃｒｏｆｌｕｉｄｉｃｓ　Ｃｏｒｐｏｒａｔｉｏｎ　製）に通し、１７５ＭＰａで１回処理することで、光吸収材料分散液を調製した。これを、日本精線（株）製のファインメットＮＦで濾過し、光吸収材料添加液を調製した。 <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.
　（ドープの調製）
　下記組成のドープを調製した。まず、加圧溶解タンクにメチレンクロライドとエタノールを添加した。これに、ＣＯＰ－Ａ（シクロオレフィン樹脂）、上記光吸収材料添加液（光吸収材料）を撹拌しながら投入し、加熱し、撹拌しながら、完全に溶解させた。これを、安積濾紙（株）製の安積濾紙Ｎｏ．２４４を使用して濾過し、ドープを調製した。
　ジクロロメタン：３００質量部
　エタノール：１９質量部
　ＣＯＰ－Ｂ（シクロオレフィン樹脂）：１００質量部
　光吸収材料添加液（光吸収材料Ａ）：９８質量部 (Preparation of dope)
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): 100 parts by mass Light absorption material additive liquid (light absorption material A): 98 parts by mass
　（製膜）
　次いで、無端ベルト流延装置を用い、ドープを、温度３３℃、１５００ｍｍ幅でステンレスベルト支持体上に均一に流延した。ステンレスベルトの温度は３０℃に制御した。ステンレスベルト支持体上に流延したドープ中の残留溶媒量が３０質量％になるまで溶媒を蒸発させた後、剥離張力１３０Ｎ／ｍで、ステンレスベルト支持体上から剥離した。
　剥離して得られた流延膜を、１６０℃（樹脂のＴｇ－１０℃）の条件下で幅方向（ＴＤ方向）に延伸率５０％で延伸した。延伸開始時の残留溶剤は１０質量％であった。次いで、乾燥ゾーンを多数のローラーで搬送させながら、１３０℃で乾燥させた。その後、巻き取り、厚み４０μｍのフィルム２０９を得た。 (Film formation)
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. Then, 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 μm.
　得られたフィルム２０１～２０９の吸光係数Ａ２を、上記と同様の方法で測定した。また、得られたフィルム２０１～２０９の平均吸収率を、以下の方法で測定した。 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.
　［平均吸収率］
　上記方法で、フィルムの吸光度を測定した。
　　吸光度＝吸光係数（／μｍ）×フィルムの厚み（μｍ）／ｌｏｇ１０
　得られた値を、下記式に当てはめて、平均吸収率を測定した。
　　平均吸収率（％）＝１００－１０^（２－吸光度） [Average absorption rate]
The absorbance of the film was measured by the above method.
Absorbance = extinction coefficient (/ μm) × film thickness (μm) / log10
The obtained value was applied to the following formula, and the average absorption rate was measured.
Average absorption rate (%) = 100-10 ^ (2-absorbance)
　得られたフィルム２０１～２０９の組成および物性を、表２に示す。 Table 2 shows the composition and physical characteristics of the obtained films 201 to 209.
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000010
　３．偏光板の作製
　＜実施例１～９および比較例１～６＞
　（偏光子の作製）
　重合度２４００、ケン化度９９．７モル％のポリビニルアルコール樹脂フィルム（ＰＶＡ）を準備した。当該フィルムを、３０℃のヨウ素水溶液中で染色しながらフィルム搬送方向に３倍に延伸し、次いで、６０℃の４質量％ホウ酸、５質量％のヨウ化カリウム水溶液中で、総延伸倍率が元長の６倍となるように延伸した。さらに、延伸したフィルムを３０℃の２質量％のヨウ化カリウム水溶液中に数秒浸漬することで洗浄した。得られた延伸フィルムを９０℃で乾燥し、厚み２５μｍの偏光子を得た。 3. 3. Fabrication of Polarizing Plate <Examples 1 to 9 and Comparative Examples 1 to 6>
(Manufacturing of a modulator)
A polyvinyl alcohol resin film (PVA) having a degree of polymerization of 2400 and a degree of saponification of 99.7 mol% was prepared. The film was stretched 3 times in the film transport direction while being dyed in an aqueous iodine solution at 30 ° C., and then in a 4% by mass boric acid and 5% by mass potassium iodide aqueous solution at 60 ° C., the total draw ratio was It was stretched to be 6 times the original length. Further, 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 μm.
　（積層体の作製）
　表３の第１保護フィルムの一方の面に、剥離フィルムとして厚み４０μｍのポリエチレンテレフタレートフィルム（ＰＥＴフィルム）を、接着剤で貼り付けた。この第１保護フィルムの他方の面上に、偏光子および表３の第２保護フィルムを、アクリル系紫外線硬化型接着剤を介して積層し、貼り合わせて、積層体を作製した。接着層の厚みは、１μｍであった。 (Preparation of laminated body)
A polyethylene terephthalate film (PET film) having a thickness of 40 μm 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 μm.
　（積層体の切断）
　得られた積層体の剥離フィルムの表面に、波長９．４μｍの炭酸ガスレーザーを照射して積層体を切断し、偏光板を得た。切断条件は、周波数２０ｋＨｚ、出力：５９Ｗ、速度：６０ｍ／分とした。 (Cut of laminated body)
The surface of the release film of the obtained laminate was irradiated with a carbon dioxide laser having a wavelength of 9.4 μm 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.
　（評価）
　得られた偏光板の切断部の断面形状、生産性および表示特性を、以下の方法で評価した。 (evaluation)
The cross-sectional shape, productivity and display characteristics of the cut portion of the obtained polarizing plate were evaluated by the following methods.
　１）偏光板の切断端面の形状
　得られた偏光板の切断端面と直交し、かつフィルムの積層方向（偏光板の厚み方向）に沿って裁断機で切り出した。切り出した面における、偏光板のレーザー切断端面の傾斜角度φを光学顕微鏡により観察した（図４Ｂ参照）。そして、上記断面において、レーザー切断部における、剥離フィルムの第１保護フィルムとは反対側の端点Ｐ１と、偏光子の第２保護フィルム側の端点Ｐ２とを結ぶ直線Ｌ１の、積層方向Ｌ０に対するなす角度φを測定した。 1) Shape of the cut end face of the polarizing plate The film was cut out by a cutting machine at right angles to the cut end face of the obtained polarizing plate and along the laminating direction of the film (thickness direction of the polarizing plate). The inclination angle φ of the laser-cut end surface of the polarizing plate on the cut surface was observed with an optical microscope (see FIG. 4B). Then, in the above cross section, the stacking direction L 0 of the straight line L1 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 in the laser cutting portion. The angle φ with respect to the object was measured.
　２）生産性
　得られた積層体をレーザー光により切断して、３００×２１０×０．１ｍｍの偏光板を１００枚準備した。それぞれの偏光板について、ＰＥＴフィルムの剥離性を粘着テープによる９０°剥離試験により測定し、以下の基準で評価した。
　◎：剥離不良なし
　○：剥離できるが、剥離残りが僅かにあるが問題とならないレベル
　△：剥離できるが、剥離残りが時々発生し、やや問題となるレベル
　×：剥離できるが、剥離残りが多くの偏光板で発生し、問題となるレベル
　○以上であれば良好と判断した。 2) Productivity The obtained laminate was cut with a laser beam to prepare 100 polarizing plates having a size of 300 × 210 × 0.1 mm. For each polarizing plate, the peelability of the PET film was measured by a 90 ° peeling test using an adhesive tape, and evaluated according to the following criteria.
⊚: No peeling failure ○: Peelable, but there is a small amount of peeling residue but not a problem level △: Peeling is possible, but peeling residue sometimes occurs and is a little problematic level ×: Peeling is possible, but there is a lot of peeling residue If the level is above the problematic level ○, it is judged to be good.
　３）表示特性
　ＶＡ型液晶表示装置であるＳＯＮＹ社製４０型ディスプレイＫＬＶ－４０Ｊ３０００にあらかじめ貼合されていた偏光板を注意深く剥がした。そして、もともと貼られていた偏光板の透過軸と一致するように、レーザーカットした偏光板を貼り付け、液晶表示装置を作製した。具体的には、液晶セル（液晶表示素子）のガラス基板上に、レーザーカットした偏光板を、その第２保護フィルムがガラス基板側となるように、粘着剤を介して配置し、押圧して貼り付けた。それにより、液晶表示装置を得た。 3) Display characteristics The polarizing plate previously attached to the 40-inch display KLV-40J3000 manufactured by Sony Corporation, which is a VA type liquid crystal display device, was carefully peeled off. Then, a laser-cut polarizing plate was attached so as to coincide with the transmission axis of the originally attached polarizing plate, and a liquid crystal display device was manufactured. Specifically, a laser-cut polarizing plate is placed on the glass substrate of the liquid crystal cell (liquid crystal display element) via an adhesive so that the second protective film is on the glass substrate side, and pressed. I pasted it. As a result, a liquid crystal display device was obtained.
　そして、得られた液晶表示装置を６０℃９０ＲＨ％の環境下で５００時間保存した。そして、保存前（初期）と保存後（湿熱耐久後）のそれぞれについて、表示装置の全画面を黒表示させた状態で暗室にて目視観察し、表示画面の端部の表示ムラ（光漏れ）を評価した。保存前（初期）と保存後（湿熱耐久後）の端部の表示ムラは、それぞれ以下の基準で評価した。 Then, 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.
　（初期）
　◎：正面方向から４５°の角度からの目視評価で光漏れが観測されない
　○：正面方向から４５°の角度からの目視評価で光漏れがわずかに観測されるが、問題ないレベル
　△：正面方向から４５°の角度からの目視評価で光漏れが観測され、問題となるレベル
　×：正面方向から４５°の角度からの目視評価で光漏れが顕著に観測され、問題となるレベル
　○以上であれば良好と判断した。 (initial)
⊚: No light leakage is observed by visual evaluation from an angle of 45 ° from the front direction ○: Light leakage is slightly observed by visual evaluation from an angle of 45 ° from the front direction, but there is no problem level △: Front direction Light leakage is observed by visual evaluation from an angle of 45 ° from, and is a problematic level. ×: Light leakage is significantly observed by visual evaluation from an angle of 45 ° from the front, and it is a problematic level. It was judged to be good.
　（保存後）
　◎：保存前と同様に、正面方向から４５°の角度からの目視評価で光漏れが観測されない
　○：保存前と比べ、正面方向から４５°の角度からの目視評価で光漏れがわずかに観測されるが、問題ないレベル
　△：保存前と比べ、正面方向から４５°の角度からの目視評価で光漏れが観測され、問題となるレベル
　×：保存前と比べ、正面方向から４５°の角度からの目視評価で光漏れが顕著に観測され、問題となるレベル
　○以上であれば良好と判断した。 (After saving)
⊚: 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. Δ: Light leakage is observed by visual evaluation from an angle of 45 ° from the front compared to before storage, and 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.
　実施例１～９および比較例１～６の評価結果を、表３に示す。
Figure JPOXMLDOC01-appb-T000011
 The evaluation results of Examples 1 to 9 and Comparative Examples 1 to 6 are shown in Table 3.
Figure JPOXMLDOC01-appb-T000011
　表３に示されるように、第２保護フィルムの吸光係数Ａ２が一定以下であり、かつ第１保護フィルムと第２保護フィルムの吸光係数の比Ａ１／Ａ２が一定以下である実施例１～９の偏光板は、いずれもレーザー切断部の切断端面の傾斜角度φが、０．５～１０°と小さいことがわかる。そして、これらの偏光板を用いた液晶表示装置は、画面の端部の表示ムラが抑制され、偏光板のＰＥＴフィルムの剥離性も良いことがわかる。 As shown in Table 3, Examples 1 to 9 in which the extinction coefficient A2 of the second protective film is not more than a certain value and the ratio A1 / A2 of the extinction coefficient of the first protective film to the second protective film is not more than a certain value. It can be seen that all of the polarizing plates of No. 1 have a small inclination angle φ of the cut end face of the laser cutting portion of 0.5 to 10 °. It can be seen that the liquid crystal display device using these polarizing plates suppresses display unevenness at the edge of the screen and has good peelability of the PET film of the polarizing plate.
　これに対し、第１保護フィルムと第２保護フィルムの吸光係数の比Ａ１／Ａ２が大きい比較例１および３の偏光板は、いずれもレーザー切断部の切断端面の傾斜角度φが、１２°以上と大きいことがわかる。そして、これらの偏光板を用いた液晶表示装置は、初期の端部の表示ムラが生じることがわかる。また、第２保護フィルムの吸光係数Ａ２が１．０×１０２～４．５×１０２／μｍの範囲を超える比較例２の偏光板は、レーザー切断部の切断端面の傾斜角度φが０．５°未満と小さいことから、液晶表示装置に貼合した際、押し圧の影響により、貼り付け後の切断端面の傾斜角度が貼合面に対して直角でなくなるため、当該偏光板を用いた液晶表示装置は、初期の端部の表示ムラが生じることがわかる。 On the other hand, 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 φ 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 / μm, the inclination angle φ of the cut end surface of the laser cut portion is 0. Since it is as small as less than 5.5 °, when it is attached to a liquid crystal display device, the tilt angle of the cut end surface after attachment is not perpendicular to the attached surface due to the influence of pressing pressure, so the polarizing plate is used. It can be seen that the liquid crystal display device that had been used had an initial display unevenness at the end.
　また、偏光板の初期の切断端面の傾斜角度φが０°に近い比較例２の液晶表示装置では、主に湿熱保存後の端部の表示ムラが生じやすく（図２Ａ参照）；偏光板の初期の切断端面の傾斜角度φが１０°を超える比較例１の液晶表示装置では、主に初期の端部の表示ムラが生じることがわかる（図１Ａ参照）。 Further, in the liquid crystal display device of Comparative Example 2 in which the inclination angle φ of the initial cut end surface of the polarizing plate is close to 0 °, display unevenness of the end portion is likely to occur mainly after moist heat storage (see FIG. 2A); It can be seen that in the liquid crystal display device of Comparative Example 1 in which the inclination angle φ of the initial cut end surface exceeds 10 °, display unevenness of the initial end portion mainly occurs (see FIG. 1A).
　また、偏光板の初期の切断端面の傾斜角度φが極端に大きい比較例３および４の液晶表示装置では、初期および湿熱保存後のいずれにおいても表示ムラを抑制しきれないことがわかる。これは、初期の切断端面の傾斜角度φが１０°を超えて著しく大きいことにより、表示ムラが発生した状態のままとなること、および、吸湿時の偏光子の膨張しようとする力に対して保護フィルムの収縮しようとする力が大きくなりすぎることによると考えられる。 Further, it can be seen that the liquid crystal display devices of Comparative Examples 3 and 4 in which the inclination angle φ 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 φ 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.
　本出願は、２０２０年１０月２３日出願の特願２０２０－１７８１７３に基づく優先権を主張する。当該出願明細書に記載された内容は、すべて本願明細書に援用される。 This application claims priority based on Japanese Patent Application No. 2020-178173 filed on October 23, 2020. All the contents described in the application specification are incorporated in the application specification.
　本発明によれば、生産性を低下させることなく、レーザー光での切断加工が可能であり、かつ表示装置の端部の表示ムラを抑制できる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を提供することができる。 According to the present invention, 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.
　１０　偏光板
　１０ａ　切断端面
　１１　偏光子
　１２　第１保護フィルム
　１３　第２保護フィルム
　１４　剥離フィルム
　２０　積層体
　３０　液晶表示素子
　４０　第１偏光板
　５０　第１偏光板
　１００　表示装置
　Ｌ　レーザー光
　φ　傾斜角度 10 Polarizing plate 10a Cut end face 11 Polarizer 12 First protective film 13 Second protective film 14 Release film 20 Laminated body 30 Liquid crystal display element 40 First polarizing plate 50 First polarizing plate 100 Display device L Laser light φ Tilt angle

Claims (8)

  1. 　偏光子と、前記偏光子の一方の面に配置された第１保護フィルムと、前記偏光子の他方の面に配置された第２保護フィルムと、前記第１保護フィルムを挟んで前記偏光子とは反対側の面に配置された剥離フィルムとが積層された偏光板であって、
    　前記第２保護フィルムの、ＡＴＲ法で測定される波長９．４μｍの光の吸光係数Ａ２は、１．０×１０２～４．５×１０２／μｍであり、
    　前記偏光板は、切断端面を有し、
    　前記偏光板の、前記積層方向に沿った断面において、
    　前記切断端面における、前記剥離フィルムの前記第１保護フィルムとは反対側の端点Ｐ１と、前記偏光子の前記第２保護フィルム側の端点Ｐ２とを結んだ直線の、前記積層方向に対する傾斜角度は、０．５～１０°である、
    　偏光板。     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 polarizing element with the first protective film interposed therebetween. Is a polarizing plate in which a release film arranged on the opposite surface is laminated.
    The extinction coefficient A2 of the light having a wavelength of 9.4 μm measured by the ATR method of the second protective film is 1.0 × 10 2 to 4.5 × 10 2 / μm.
    The polarizing plate has a cut end face and has a cut end face.
    In the cross section of the polarizing plate along the stacking direction,
    The inclination angle of the straight line connecting the end point P1 of the release film opposite to the first protective film and the end point P2 of the polarizing element on the second protective film side of the cut end surface with respect to the stacking direction is , 0.5-10 °,
    Polarizer.
  2. 　前記第１保護フィルムの、ＡＴＲ法で測定される波長９．４μｍの光の吸光係数Ａ１と、前記第２保護フィルムの、ＡＴＲ法で測定される波長９．４μｍの光の吸光係数Ａ２との比Ａ１／Ａ２は、１～５である、
    　請求項１に記載の偏光板。     The extinction coefficient A1 of the light having a wavelength of 9.4 μm measured by the ATR method of the first protective film and the extinction coefficient A2 of the light having a wavelength of 9.4 μm measured by the ATR method of the second protective film. The ratios A1 / A2 are 1-5,
    The polarizing plate according to claim 1.
  3. 　前記第１保護フィルムは、（メタ）アクリル樹脂またはシクロオレフィン樹脂を含む、
    　請求項１または２に記載の偏光板。     The first protective film contains a (meth) acrylic resin or a cycloolefin resin.
    The polarizing plate according to claim 1 or 2.
  4. 　前記第２保護フィルムは、シクロオレフィン樹脂を含む、
    　請求項１～３のいずれか一項に記載の偏光板。     The second protective film contains a cycloolefin resin.
    The polarizing plate according to any one of claims 1 to 3.
  5. 　前記第２保護フィルムは、エステル化合物および（メタ）アクリル重合体粒子からなる群より選ばれる一以上の光吸収材料をさらに含む、
    　請求項４に記載の偏光板。     The second protective film further comprises one or more light absorbing materials selected from the group consisting of ester compounds and (meth) acrylic polymer particles.
    The polarizing plate according to claim 4.
  6. 　前記第２保護フィルムにおける前記光吸収材料の質量基準の含有量は、前記第１保護フィルムにおける前記光吸収材料の質量基準の含有量よりも多い、
    　請求項５に記載の偏光板。     The mass-based content of the light-absorbing material in the second protective film is higher than the mass-based content of the light-absorbing material in the first protective film.
    The polarizing plate according to claim 5.
  7. 　偏光子と、前記偏光子の一方の面に配置された第１保護フィルムと、前記偏光子の他方の面に配置された第２保護フィルムと、前記第１保護フィルムの前記偏光子とは反対側の面に配置された剥離フィルムとを含む積層体であって、前記第１保護フィルムの、ＡＴＲ法で測定される波長９．４μｍの光の吸光係数Ａ１と、前記第２保護フィルムの、ＡＴＲ法で測定される波長９．４μｍの光の吸光係数Ａ２との比Ａ１／Ａ２が１～５である積層体を準備する工程と、
    　前記剥離フィルム側から前記積層体にレーザー光を照射して、前記積層体を、前記積層体の積層方向に沿って切断する工程と
    　を有する、
    　偏光板の製造方法。     The polarizing element, the first protective film arranged on one surface of the polarizing element, the second protective film arranged on the other surface of the polarizing element, and the polarizing element of the first protective film are opposite to each other. A laminate including a release film arranged on the side surface, wherein the first protective film has an absorption coefficient A1 of light having a wavelength of 9.4 μm measured by the ATR method, and the second protective film has a light absorption coefficient A1. A step of preparing a laminate having a ratio A1 / A2 to the absorption coefficient A2 of light having a wavelength of 9.4 μm measured by the ATR method of 1 to 5.
    It comprises a step of irradiating the laminated body with a laser beam from the release film side to cut the laminated body along the laminating direction of the laminated body.
    Method for manufacturing a polarizing plate.
  8. 　表示素子の少なくとも一方の面に、請求項１～６のいずれか一項に記載の偏光板を、前記第２保護フィルムが前記表示素子側となるように貼り付ける工程を含む、
    　表示装置の製造方法。     A step of attaching the polarizing plate according to any one of claims 1 to 6 to at least one surface of the display element so that the second protective film is on the display element side.
    How to manufacture a display device.
PCT/JP2021/038792 2020-10-23 2021-10-20 Polarizing plate, method for manufacturing same, and method for manufacturing display device WO2022085726A1 (en)

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