CN115308821B - Polyester film for protecting polarizer - Google Patents
Polyester film for protecting polarizer Download PDFInfo
- Publication number
- CN115308821B CN115308821B CN202211005534.4A CN202211005534A CN115308821B CN 115308821 B CN115308821 B CN 115308821B CN 202211005534 A CN202211005534 A CN 202211005534A CN 115308821 B CN115308821 B CN 115308821B
- Authority
- CN
- China
- Prior art keywords
- polyester film
- polarizing plate
- protecting
- film
- elastic modulus
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 229920006267 polyester film Polymers 0.000 title claims abstract description 403
- 239000004973 liquid crystal related substance Substances 0.000 claims abstract description 116
- 230000005540 biological transmission Effects 0.000 claims abstract description 76
- 238000010521 absorption reaction Methods 0.000 claims abstract description 33
- 239000010410 layer Substances 0.000 claims description 37
- 238000010438 heat treatment Methods 0.000 claims description 28
- 238000001816 cooling Methods 0.000 claims description 18
- 210000002858 crystal cell Anatomy 0.000 claims description 16
- 239000011247 coating layer Substances 0.000 claims description 11
- 239000010408 film Substances 0.000 description 161
- 230000001681 protective effect Effects 0.000 description 111
- 238000004519 manufacturing process Methods 0.000 description 53
- 238000000034 method Methods 0.000 description 31
- 230000015572 biosynthetic process Effects 0.000 description 15
- 230000000052 comparative effect Effects 0.000 description 14
- -1 polarizing plate Substances 0.000 description 13
- 229920000139 polyethylene terephthalate Polymers 0.000 description 13
- 239000005020 polyethylene terephthalate Substances 0.000 description 13
- 238000005266 casting Methods 0.000 description 12
- 229920005989 resin Polymers 0.000 description 11
- 239000011347 resin Substances 0.000 description 11
- 238000005259 measurement Methods 0.000 description 10
- 229920001225 polyester resin Polymers 0.000 description 10
- 239000004645 polyester resin Substances 0.000 description 10
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 9
- OFOBLEOULBTSOW-UHFFFAOYSA-N Malonic acid Chemical compound OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 8
- 239000011521 glass Substances 0.000 description 8
- 239000002346 layers by function Substances 0.000 description 7
- 230000008569 process Effects 0.000 description 7
- 229920002284 Cellulose triacetate Polymers 0.000 description 6
- KKEYFWRCBNTPAC-UHFFFAOYSA-N Terephthalic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 description 6
- NNLVGZFZQQXQNW-ADJNRHBOSA-N [(2r,3r,4s,5r,6s)-4,5-diacetyloxy-3-[(2s,3r,4s,5r,6r)-3,4,5-triacetyloxy-6-(acetyloxymethyl)oxan-2-yl]oxy-6-[(2r,3r,4s,5r,6s)-4,5,6-triacetyloxy-2-(acetyloxymethyl)oxan-3-yl]oxyoxan-2-yl]methyl acetate Chemical compound O([C@@H]1O[C@@H]([C@H]([C@H](OC(C)=O)[C@H]1OC(C)=O)O[C@H]1[C@@H]([C@@H](OC(C)=O)[C@H](OC(C)=O)[C@@H](COC(C)=O)O1)OC(C)=O)COC(=O)C)[C@@H]1[C@@H](COC(C)=O)O[C@@H](OC(C)=O)[C@H](OC(C)=O)[C@H]1OC(C)=O NNLVGZFZQQXQNW-ADJNRHBOSA-N 0.000 description 6
- 239000011248 coating agent Substances 0.000 description 6
- 238000000576 coating method Methods 0.000 description 6
- 239000007788 liquid Substances 0.000 description 6
- 150000002009 diols Chemical class 0.000 description 5
- 230000009477 glass transition Effects 0.000 description 5
- 239000002245 particle Substances 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 4
- 238000005886 esterification reaction Methods 0.000 description 4
- 238000011156 evaluation Methods 0.000 description 4
- QQVIHTHCMHWDBS-UHFFFAOYSA-N isophthalic acid Chemical compound OC(=O)C1=CC=CC(C(O)=O)=C1 QQVIHTHCMHWDBS-UHFFFAOYSA-N 0.000 description 4
- 238000002360 preparation method Methods 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- 239000000758 substrate Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 229920002799 BoPET Polymers 0.000 description 3
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 3
- ZMANZCXQSJIPKH-UHFFFAOYSA-N Triethylamine Chemical compound CCN(CC)CC ZMANZCXQSJIPKH-UHFFFAOYSA-N 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 238000005520 cutting process Methods 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 239000008188 pellet Substances 0.000 description 3
- 238000006068 polycondensation reaction Methods 0.000 description 3
- 229920000728 polyester Polymers 0.000 description 3
- 229920000642 polymer Polymers 0.000 description 3
- 230000008646 thermal stress Effects 0.000 description 3
- 239000006097 ultraviolet radiation absorber Substances 0.000 description 3
- DNIAPMSPPWPWGF-VKHMYHEASA-N (+)-propylene glycol Chemical compound C[C@H](O)CO DNIAPMSPPWPWGF-VKHMYHEASA-N 0.000 description 2
- YPFDHNVEDLHUCE-UHFFFAOYSA-N 1,3-propanediol Substances OCCCO YPFDHNVEDLHUCE-UHFFFAOYSA-N 0.000 description 2
- 229940035437 1,3-propanediol Drugs 0.000 description 2
- PXGZQGDTEZPERC-UHFFFAOYSA-N 1,4-cyclohexanedicarboxylic acid Chemical compound OC(=O)C1CCC(C(O)=O)CC1 PXGZQGDTEZPERC-UHFFFAOYSA-N 0.000 description 2
- SVTBMSDMJJWYQN-UHFFFAOYSA-N 2-methylpentane-2,4-diol Chemical compound CC(O)CC(C)(C)O SVTBMSDMJJWYQN-UHFFFAOYSA-N 0.000 description 2
- 229920001634 Copolyester Polymers 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 239000004372 Polyvinyl alcohol Substances 0.000 description 2
- 235000010724 Wisteria floribunda Nutrition 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- WNLRTRBMVRJNCN-UHFFFAOYSA-N adipic acid Chemical compound OC(=O)CCCCC(O)=O WNLRTRBMVRJNCN-UHFFFAOYSA-N 0.000 description 2
- 230000032683 aging Effects 0.000 description 2
- ADCOVFLJGNWWNZ-UHFFFAOYSA-N antimony trioxide Chemical compound O=[Sb]O[Sb]=O ADCOVFLJGNWWNZ-UHFFFAOYSA-N 0.000 description 2
- 239000012298 atmosphere Substances 0.000 description 2
- WERYXYBDKMZEQL-UHFFFAOYSA-N butane-1,4-diol Chemical compound OCCCCO WERYXYBDKMZEQL-UHFFFAOYSA-N 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000008602 contraction Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000007334 copolymerization reaction Methods 0.000 description 2
- XBZSBBLNHFMTEB-UHFFFAOYSA-N cyclohexane-1,3-dicarboxylic acid Chemical compound OC(=O)C1CCCC(C(O)=O)C1 XBZSBBLNHFMTEB-UHFFFAOYSA-N 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000010030 laminating Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- SLCVBVWXLSEKPL-UHFFFAOYSA-N neopentyl glycol Chemical compound OCC(C)(C)CO SLCVBVWXLSEKPL-UHFFFAOYSA-N 0.000 description 2
- BDJRBEYXGGNYIS-UHFFFAOYSA-N nonanedioic acid Chemical compound OC(=O)CCCCCCCC(O)=O BDJRBEYXGGNYIS-UHFFFAOYSA-N 0.000 description 2
- 239000012788 optical film Substances 0.000 description 2
- XNGIFLGASWRNHJ-UHFFFAOYSA-N phthalic acid Chemical compound OC(=O)C1=CC=CC=C1C(O)=O XNGIFLGASWRNHJ-UHFFFAOYSA-N 0.000 description 2
- WLJVNTCWHIRURA-UHFFFAOYSA-N pimelic acid Chemical compound OC(=O)CCCCCC(O)=O WLJVNTCWHIRURA-UHFFFAOYSA-N 0.000 description 2
- 229920003207 poly(ethylene-2,6-naphthalate) Polymers 0.000 description 2
- 239000011112 polyethylene naphthalate Substances 0.000 description 2
- 229920000166 polytrimethylene carbonate Polymers 0.000 description 2
- 229920002451 polyvinyl alcohol Polymers 0.000 description 2
- 229960004063 propylene glycol Drugs 0.000 description 2
- 235000013772 propylene glycol Nutrition 0.000 description 2
- CXMXRPHRNRROMY-UHFFFAOYSA-N sebacic acid Chemical compound OC(=O)CCCCCCCCC(O)=O CXMXRPHRNRROMY-UHFFFAOYSA-N 0.000 description 2
- TYFQFVWCELRYAO-UHFFFAOYSA-N suberic acid Chemical compound OC(=O)CCCCCCC(O)=O TYFQFVWCELRYAO-UHFFFAOYSA-N 0.000 description 2
- DNIAPMSPPWPWGF-GSVOUGTGSA-N (R)-(-)-Propylene glycol Chemical compound C[C@@H](O)CO DNIAPMSPPWPWGF-GSVOUGTGSA-N 0.000 description 1
- 229940043375 1,5-pentanediol Drugs 0.000 description 1
- RTBFRGCFXZNCOE-UHFFFAOYSA-N 1-methylsulfonylpiperidin-4-one Chemical compound CS(=O)(=O)N1CCC(=O)CC1 RTBFRGCFXZNCOE-UHFFFAOYSA-N 0.000 description 1
- GBURUDXSBYGPBL-UHFFFAOYSA-N 2,2,3-trimethylhexanedioic acid Chemical compound OC(=O)C(C)(C)C(C)CCC(O)=O GBURUDXSBYGPBL-UHFFFAOYSA-N 0.000 description 1
- JZUMVFMLJGSMRF-UHFFFAOYSA-N 2-Methyladipic acid Chemical compound OC(=O)C(C)CCCC(O)=O JZUMVFMLJGSMRF-UHFFFAOYSA-N 0.000 description 1
- BBITXNWQALLODC-UHFFFAOYSA-N 2-[4-(4-oxo-3,1-benzoxazin-2-yl)phenyl]-3,1-benzoxazin-4-one Chemical compound C1=CC=C2C(=O)OC(C3=CC=C(C=C3)C=3OC(C4=CC=CC=C4N=3)=O)=NC2=C1 BBITXNWQALLODC-UHFFFAOYSA-N 0.000 description 1
- POAOYUHQDCAZBD-UHFFFAOYSA-N 2-butoxyethanol Chemical compound CCCCOCCO POAOYUHQDCAZBD-UHFFFAOYSA-N 0.000 description 1
- XCSGHNKDXGYELG-UHFFFAOYSA-N 2-phenoxyethoxybenzene Chemical compound C=1C=CC=CC=1OCCOC1=CC=CC=C1 XCSGHNKDXGYELG-UHFFFAOYSA-N 0.000 description 1
- WMRCTEPOPAZMMN-UHFFFAOYSA-N 2-undecylpropanedioic acid Chemical compound CCCCCCCCCCCC(C(O)=O)C(O)=O WMRCTEPOPAZMMN-UHFFFAOYSA-N 0.000 description 1
- VPWNQTHUCYMVMZ-UHFFFAOYSA-N 4,4'-sulfonyldiphenol Chemical compound C1=CC(O)=CC=C1S(=O)(=O)C1=CC=C(O)C=C1 VPWNQTHUCYMVMZ-UHFFFAOYSA-N 0.000 description 1
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- 239000005041 Mylar™ Substances 0.000 description 1
- ALQSHHUCVQOPAS-UHFFFAOYSA-N Pentane-1,5-diol Chemical compound OCCCCCO ALQSHHUCVQOPAS-UHFFFAOYSA-N 0.000 description 1
- KZTYYGOKRVBIMI-UHFFFAOYSA-N S-phenyl benzenesulfonothioate Natural products C=1C=CC=CC=1S(=O)(=O)C1=CC=CC=C1 KZTYYGOKRVBIMI-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- KDYFGRWQOYBRFD-UHFFFAOYSA-N Succinic acid Natural products OC(=O)CCC(O)=O KDYFGRWQOYBRFD-UHFFFAOYSA-N 0.000 description 1
- XDODWINGEHBYRT-UHFFFAOYSA-N [2-(hydroxymethyl)cyclohexyl]methanol Chemical compound OCC1CCCCC1CO XDODWINGEHBYRT-UHFFFAOYSA-N 0.000 description 1
- YIMQCDZDWXUDCA-UHFFFAOYSA-N [4-(hydroxymethyl)cyclohexyl]methanol Chemical compound OCC1CCC(CO)CC1 YIMQCDZDWXUDCA-UHFFFAOYSA-N 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 239000001361 adipic acid Substances 0.000 description 1
- 235000011037 adipic acid Nutrition 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- JFCQEDHGNNZCLN-UHFFFAOYSA-N anhydrous glutaric acid Natural products OC(=O)CCCC(O)=O JFCQEDHGNNZCLN-UHFFFAOYSA-N 0.000 description 1
- FNGGVJIEWDRLFV-UHFFFAOYSA-N anthracene-1,2-dicarboxylic acid Chemical compound C1=CC=CC2=CC3=C(C(O)=O)C(C(=O)O)=CC=C3C=C21 FNGGVJIEWDRLFV-UHFFFAOYSA-N 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- KDYFGRWQOYBRFD-NUQCWPJISA-N butanedioic acid Chemical compound O[14C](=O)CC[14C](O)=O KDYFGRWQOYBRFD-NUQCWPJISA-N 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 150000001925 cycloalkenes Chemical class 0.000 description 1
- LNGJOYPCXLOTKL-UHFFFAOYSA-N cyclopentane-1,3-dicarboxylic acid Chemical compound OC(=O)C1CCC(C(O)=O)C1 LNGJOYPCXLOTKL-UHFFFAOYSA-N 0.000 description 1
- INSRQEMEVAMETL-UHFFFAOYSA-N decane-1,1-diol Chemical compound CCCCCCCCCC(O)O INSRQEMEVAMETL-UHFFFAOYSA-N 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000000539 dimer Substances 0.000 description 1
- OREAFAJWWJHCOT-UHFFFAOYSA-N dimethylmalonic acid Chemical compound OC(=O)C(C)(C)C(O)=O OREAFAJWWJHCOT-UHFFFAOYSA-N 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 229940093476 ethylene glycol Drugs 0.000 description 1
- XXMIOPMDWAUFGU-UHFFFAOYSA-N hexane-1,6-diol Chemical compound OCCCCCCO XXMIOPMDWAUFGU-UHFFFAOYSA-N 0.000 description 1
- 229940051250 hexylene glycol Drugs 0.000 description 1
- PNDPGZBMCMUPRI-UHFFFAOYSA-N iodine Chemical compound II PNDPGZBMCMUPRI-UHFFFAOYSA-N 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 229940097364 magnesium acetate tetrahydrate Drugs 0.000 description 1
- XKPKPGCRSHFTKM-UHFFFAOYSA-L magnesium;diacetate;tetrahydrate Chemical compound O.O.O.O.[Mg+2].CC([O-])=O.CC([O-])=O XKPKPGCRSHFTKM-UHFFFAOYSA-L 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- ABMFBCRYHDZLRD-UHFFFAOYSA-N naphthalene-1,4-dicarboxylic acid Chemical compound C1=CC=C2C(C(=O)O)=CC=C(C(O)=O)C2=C1 ABMFBCRYHDZLRD-UHFFFAOYSA-N 0.000 description 1
- DFFZOPXDTCDZDP-UHFFFAOYSA-N naphthalene-1,5-dicarboxylic acid Chemical compound C1=CC=C2C(C(=O)O)=CC=CC2=C1C(O)=O DFFZOPXDTCDZDP-UHFFFAOYSA-N 0.000 description 1
- VAWFFNJAPKXVPH-UHFFFAOYSA-N naphthalene-1,6-dicarboxylic acid Chemical compound OC(=O)C1=CC=CC2=CC(C(=O)O)=CC=C21 VAWFFNJAPKXVPH-UHFFFAOYSA-N 0.000 description 1
- RXOHFPCZGPKIRD-UHFFFAOYSA-N naphthalene-2,6-dicarboxylic acid Chemical compound C1=C(C(O)=O)C=CC2=CC(C(=O)O)=CC=C21 RXOHFPCZGPKIRD-UHFFFAOYSA-N 0.000 description 1
- 229940117969 neopentyl glycol Drugs 0.000 description 1
- 239000002736 nonionic surfactant Substances 0.000 description 1
- JFNLZVQOOSMTJK-KNVOCYPGSA-N norbornene Chemical compound C1[C@@H]2CC[C@H]1C=C2 JFNLZVQOOSMTJK-KNVOCYPGSA-N 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 125000000914 phenoxymethylpenicillanyl group Chemical group CC1(S[C@H]2N([C@H]1C(=O)*)C([C@H]2NC(COC2=CC=CC=C2)=O)=O)C 0.000 description 1
- 229920001707 polybutylene terephthalate Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- YXTFRJVQOWZDPP-UHFFFAOYSA-M sodium;3,5-dicarboxybenzenesulfonate Chemical compound [Na+].OC(=O)C1=CC(C(O)=O)=CC(S([O-])(=O)=O)=C1 YXTFRJVQOWZDPP-UHFFFAOYSA-M 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 125000001273 sulfonato group Chemical group [O-]S(*)(=O)=O 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- WVLBCYQITXONBZ-UHFFFAOYSA-N trimethyl phosphate Chemical compound COP(=O)(OC)OC WVLBCYQITXONBZ-UHFFFAOYSA-N 0.000 description 1
- 238000009281 ultraviolet germicidal irradiation Methods 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
- G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
- G02B1/14—Protective coatings, e.g. hard coatings
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
- B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
- B29C55/04—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique
- B29C55/06—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique parallel with the direction of feed
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/18—Manufacture of films or sheets
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
- G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
- G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
-
- 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
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/133528—Polarisers
Landscapes
- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Optics & Photonics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Nonlinear Science (AREA)
- Manufacturing & Machinery (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mathematical Physics (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Chemistry (AREA)
- Polymers & Plastics (AREA)
- Medicinal Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Polarising Elements (AREA)
- Laminated Bodies (AREA)
- Liquid Crystal (AREA)
- Surface Treatment Of Optical Elements (AREA)
- Devices For Indicating Variable Information By Combining Individual Elements (AREA)
Abstract
Providing: a polyester film for protecting a polarizing plate, which is laminated on one surface of a polarizing plate and can suppress warpage of a liquid crystal panel, satisfies the following characteristics (1) and (2). (1) The shrinkage force F f of the polyester film in the direction parallel to the transmission axis of the polarizing plate is 800N/m to 9000N/m, and (2) the ratio (F f/Fv) of the shrinkage force F f of the polyester film in the direction parallel to the transmission axis of the polarizing plate to the shrinkage force F v of the polyester film in the direction parallel to the absorption axis of the polarizing plate is 2.5 to 12.0.
Description
The present application is a divisional application of application number 201880057327.9, entitled "polarizer protective film, polarizing plate, and liquid crystal display device", having application number 2018, 09, 12.
Technical Field
The invention relates to a polarizer protective film, a polarizing plate and a liquid crystal display device.
Background
Liquid crystal display devices are in increasing demand for liquid crystal televisions, liquid crystal displays of personal computers, and the like. In general, a liquid crystal display device is constituted by a liquid crystal cell in which a transparent electrode, a liquid crystal layer, a color filter, and the like are sandwiched between glass plates, and 2 polarizing plates provided on both sides thereof, each polarizing plate being constituted by sandwiching a polarizing plate (also referred to as a polarizing film) between 2 optical films (for example, a polarizing plate protective film and a retardation film).
Accordingly, in recent years, as the thickness of a liquid crystal television screen becomes thinner and larger, backlight using LEDs is started to be used as a light source, and as the thickness of a glass substrate used for a liquid crystal panel becomes thinner than 0.7mm, there is a problem that display unevenness occurs, and improvement thereof is demanded.
The mechanism of occurrence of display unevenness is thought to occur mainly due to shrinkage of the polarizing plate, and when the polarizing plate is placed under high temperature and high humidity, shrinkage force acts in the alignment direction in order to alleviate alignment, and as a result, the liquid crystal panel warps and expands on the backlight unit side, thereby causing display unevenness.
Conventionally, as in patent documents 1 and 2 below, since the thickness of a glass substrate used in a liquid crystal panel is as thick as 0.7mm or more, shrinkage of a polarizing plate can be suppressed due to high rigidity of glass, and therefore, warpage of the liquid crystal panel does not occur and display unevenness does not become a problem.
Therefore, attempts have been made to improve the warpage of liquid crystal panels, which occurs when glass substrates are made thinner than 0.7mm, with optical films.
For example, in the case of using a cycloolefin resin as a polarizer protective film, improvement of warpage of a liquid crystal panel is insufficient, and drying property of a water gel used for bonding to a polarizer is poor, and thus there is a problem of productivity reduction.
In addition, when conventional triacetyl cellulose (TAC) is used as a polarizer protective film, there is a problem in that the liquid crystal panel warps.
Prior art literature
Patent literature
Patent document 1: japanese patent laid-open No. 2008-107499
Patent document 2: japanese patent laid-open No. 2009-198666
Disclosure of Invention
Problems to be solved by the invention
The present invention has been made in view of the above-described problems and circumstances, and an object of the present invention is to provide: a polarizer protective film, a polarizing plate and a liquid crystal display device capable of suppressing warpage of a liquid crystal panel.
Solution for solving the problem
In order to solve the above problems, the present inventors have studied the causes of the problems and the like, and have found that: the present invention has been completed based on the finding that the warping of a liquid crystal panel can be improved by setting the shrinkage force of a polyester film for protecting a polarizing plate in a specific range in a direction parallel to the light transmission axis of the polarizing plate.
In detail, the liquid crystal display device is generally laminated as follows: on one surface of the liquid crystal cell, a polarizing plate is laminated so that the transmission axis direction of the polarizing plate is parallel to the longitudinal direction of the liquid crystal display device, and on the other surface, a polarizing plate is laminated so that the absorption axis direction of the polarizing plate is parallel to the longitudinal direction of the liquid crystal display device. As a result of intensive studies using various commercially available liquid crystal display devices, the present inventors have found that: the polarizing plate having a long side in the absorption axis direction of the polarizing plate having a large shrinkage force is shrunk, and thus a problem of a shape factor of curling is easily generated (curling is easily generated in the long side direction in general); the problem is that the polarizing plate side of the upper and lower polarizing plates disposed in the cross prism has a convex light transmission axis on the long side of the polarizing plate in the liquid crystal panel due to the influence of the asymmetric configuration of the upper and lower polarizing plates in the liquid crystal panel.
Further, as a result of intensive studies, it was revealed that the shrinkage force in the longitudinal direction of the polarizing plate in which the transmission axis of the polarizing plate is a long side can be controlled according to the residual strain of the protective film, and it was found that the curling of the liquid crystal panel can be controlled by the shrinkage force.
Here, a method for measuring the shrinkage force of a polyester film for protecting a polarizing plate is described. In general, the shrinkage force of a film is a force in the shrinkage direction during temperature increase measured by setting an initial length with a very small load in a low temperature state at the start of a test using TMA or the like and maintaining the initial length. However, in the heating process, thermal expansion (hereinafter, abbreviated as thermal expansion) occurs due to an increase in the free volume and occupied volume of the polymer by heating together with shrinkage (hereinafter, abbreviated as thermal shrinkage) occurring due to recovery of residual strain associated with conformational change of the polymer, and therefore, in a temperature region around the glass transition temperature (for example, about-tg+50℃) of the polyester film, a relationship of thermal shrinkage < thermal expansion is often generated, and therefore, expansion occurs as a whole of the film, and no shrinkage force is observed.
The results of the study showed that, in the case where no shrinkage force was generated during TMA warming, shrinkage force was also generated during TMA cooling. This is because the strain caused by thermal expansion changes reversibly, and therefore returns to the original state after the temperature is raised and cooled, but only the amount of thermal shrinkage that has shrunk during the temperature raising process is cooled in a small-sized state, and therefore thermal stress is generated during the cooling process. That is, the thermal shrinkage rate of the film may be replaced with the strain of the thermal stress, and the shrinkage force after cooling may be expressed by the following formula. The heat shrinkage in the present invention includes a change in the moisture content in the heat treatment.
Shrinkage force (N/m) =thickness (mm) of film×elastic modulus (N/mm 2) ×heat shrinkage (%) 100×1000
That is, representative invention is as follows.
Item 1.
A polyester film for protecting a polarizing plate, which is laminated on one surface of a polarizing plate and satisfies the following characteristics (1) and (2).
( 1) The shrinkage force F f of the polyester film in the direction parallel to the light transmission axis of the polarizing plate is 800N/m or more and 9000N/m or less (wherein the shrinkage force F f (N/m) is the thickness (mm) x elastic modulus (N/mm 2) x the heat shrinkage rate (%) of heat treatment at 80 ℃ for 30 minutes is 100 x 1000). Here, the elastic modulus is the elastic modulus of the polyester film in the direction parallel to the light transmission axis of the polarizing plate, and the heat shrinkage rate is the heat shrinkage rate of the polyester film in the direction parallel to the light transmission axis of the polarizing plate. )
( 2) The ratio (F f/Fv) of the shrinkage force F f of the polyester film in the direction parallel to the light transmission axis of the polarizing plate to the shrinkage force F v of the polyester film in the direction parallel to the absorption axis of the polarizing plate is 2.5 to 12.0 (wherein the shrinkage force F v (N/m) is the thickness (mm) x elastic modulus (N/mm 2) x of the polyester film and the heat shrinkage rate (%) of heat treatment at 80 ℃ for 30 minutes is/(100 x 1000). Here, the elastic modulus is the elastic modulus of the polyester film in the direction parallel to the absorption axis of the polarizing plate, and the heat shrinkage rate is the heat shrinkage rate of the polyester film in the direction parallel to the absorption axis of the polarizing plate. )
Item 2.
The polyester film for protecting a polarizing plate according to item 1, which further satisfies the following feature (3).
(3) The direction in which the heat shrinkage rate of the polyester film becomes maximum is substantially parallel to the direction parallel to the light transmission axis of the polarizing plate.
Item 3.
The polyester film for protecting a polarizing plate according to item 1 or 2, wherein the polyester film has a retardation of 3000 to 30000 nm.
Item 4.
The polyester film for protecting a polarizing plate according to any one of claims 1 to 3, wherein the thickness of the polyester film is 40 to 200. Mu.m.
Item 5.
The polyester film for protecting a polarizing plate according to any one of items 1 to 4, wherein the polyester film has a hard coat layer, an antireflection layer, a low reflection layer, an antiglare layer or an antireflection antiglare layer on a surface opposite to a surface on which the polarizing plate is laminated.
Item 6.
A polyester film for protecting a polarizing plate, which is laminated on one surface of a polarizing plate and satisfies the following characteristics (1) and (2).
( 1) The shrinkage force F TD of the TD of the polyester film is not less than 800N/m and not more than 9000N/m (wherein, the shrinkage force F TD (N/m) is the thickness (mm) x elastic modulus (N/mm 2) x the heat shrinkage rate (%) of heat treatment at 80 ℃ for 30 minutes is not more than 100 x 1000). Here, the elastic modulus is the elastic modulus of the TD of the polyester film, and the heat shrinkage is the heat shrinkage of the TD of the polyester film. )
( 2) The ratio (F TD/FMD) of the shrinkage force F TD of the TD of the polyester film to the shrinkage force F MD of the MD of the polyester film is 2.5 to 12.0 (wherein the shrinkage force F MD (N/m) is the thickness (mm) x elastic modulus (N/mm 2) x 100 x 1000 of the polyester film at 80 ℃ after 30 minutes heat treatment. Here, the elastic modulus is the elastic modulus of the MD of the polyester film, and the heat shrinkage is the heat shrinkage of the MD of the polyester film. )
Item 7.
The polyester film for protecting a polarizing plate according to item 6, which further satisfies the following feature (3).
(3) The direction in which the heat shrinkage of the polyester film becomes maximum is substantially parallel to TD.
Item 8.
A polarizing plate comprising a polarizing plate and the polyester film for protecting a polarizing plate according to any one of claims 1 to 7 laminated on at least one surface of the polarizing plate.
Item 9.
A polarizing plate comprising a polarizing plate and the polyester film for protecting a polarizing plate according to any one of claims 1 to 7 laminated on one surface of the polarizing plate, wherein the polarizing plate has no film on the other surface of the polarizing plate.
Item 10.
The polarizing plate according to item 8 or 9, wherein the polarizing plate has a rectangular shape, and the long side of the polarizing plate is parallel to the light transmission axis thereof.
Item 11.
A liquid crystal display device includes: a backlight light source; and a liquid crystal cell disposed between 2 polarizing plates, at least one of the 2 polarizing plates being the polarizing plate according to any one of claims 8 to 10.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, there may be provided: a polarizer protective film, a polarizing plate and a liquid crystal display device capable of suppressing warpage of a liquid crystal panel.
Detailed Description
The polyester film for protecting a polarizing plate of the present invention is a polarizing plate protecting film formed of a polyester film and laminated on at least one surface of a polarizing plate (for example, a film formed of polyvinyl alcohol and a dye).
In the present specification, the shrinkage force of the polyester film in the direction parallel to the transmission axis of the polarizing plate means the shrinkage force of the polyester film in the direction parallel to the transmission axis of the polarizing plate laminated on one side of the polyester film.
The heat shrinkage of the polyester film in the direction parallel to the light transmission axis of the polarizing plate means the heat shrinkage of the polyester film in the direction parallel to the light transmission axis of the polarizing plate laminated on one side of the polyester film.
The elastic modulus of the polyester film in the direction parallel to the light transmission axis of the polarizing plate means the elastic modulus of the polyester film in the direction parallel to the light transmission axis of the polarizing plate laminated on one side of the polyester film.
The shrinkage force of the polyester film in the direction parallel to the absorption axis of the polarizing plate is the shrinkage force of the polyester film in the direction parallel to the absorption axis of the polarizing plate laminated on one side of the polyester film.
The heat shrinkage of the polyester film in the direction parallel to the absorption axis of the polarizing plate means the heat shrinkage of the polyester film in the direction parallel to the absorption axis of the polarizing plate laminated on one side of the polyester film.
The elastic modulus of the polyester film in the direction parallel to the absorption axis of the polarizing plate means the elastic modulus of the polyester film in the direction parallel to the absorption axis of the polarizing plate laminated on one side of the polyester film.
The direction parallel to the transmission axis of the polarizer is sometimes simply referred to as the transmission axis direction of the polarizer. The direction parallel to the absorption axis of the polarizing plate may be simply referred to as the absorption axis direction of the polarizing plate.
The polyester film for protecting a polarizing plate of the present invention preferably has a relationship in which the direction parallel to the light transmission axis of the polarizing plate and the direction in which the heat shrinkage rate of the polyester film is maximum are substantially parallel. The substantial parallelism means that the absolute value of the angle between the light transmission axis direction of the polarizing plate and the direction in which the heat shrinkage rate of the polyester film becomes maximum (hereinafter, may be simply referred to as the slope of the heat shrinkage rate) is allowed to be 15 degrees or less. The slope of the heat shrinkage is preferably 12 degrees or less, more preferably 10 degrees or less, further preferably 8 degrees or less, further preferably 6 degrees or less, particularly preferably 4 degrees or less, and most preferably 2 degrees or less. The smaller the slope of the heat shrinkage, the more preferable, and therefore, the lower limit is 0 degrees. If the slope of the heat shrinkage ratio of the polyester film is large, warpage in the oblique direction of the polarizing plate including the polyester film is generated, and the effect of reducing the warpage of the liquid crystal panel tends to be small.
When the ratio (F f/Fv) of the shrinkage force F f of the polyester film to the shrinkage force F v of the polyester film in the direction parallel to the light transmission axis of the polarizing plate to the absorption axis of the polarizing plate is 2.5 to 12.0, the absolute value of the angle between the direction parallel to the light transmission axis of the polarizing plate and the direction in which the thermal shrinkage rate of the polyester film is maximum is 40 degrees or less, and the warpage of the liquid crystal panel can be reduced. The angle is preferably 35 degrees or less.
The heat shrinkage of the polyester film, the gradient of the heat shrinkage of the polyester film, and the direction in which the heat shrinkage of the polyester film becomes maximum can be measured by the method used in examples described later.
In general, in a liquid crystal display device, 2 polarizing plates are arranged in a crossed prism relationship. If 2 polarizers are arranged in a crossed prismatic relationship, normally the light does not pass through the 2 polarizers. However, the shrinkage or warpage of the polarizing plate may cause complete cross prism disintegration, resulting in light leakage. From the viewpoint of suppressing light leakage, it is preferable that the smaller the angle between the direction in which the thermal shrinkage rate of the polarizer protective film becomes maximum and the transmission axis of the polarizer is.
The polyester film for protecting a polarizing plate of the present invention preferably has a shrinkage force F f in a direction parallel to the light transmission axis of the polarizing plate of 800N/m or more and 9000N/m or less. If the lower limit of F f is less than 800N/m, the warpage of the liquid crystal panel may not be sufficiently reduced. If the upper limit of F f exceeds 9000N/m, the shrinkage force is too strong, and there is a concern that the liquid crystal panel may warp in the opposite direction. The preferable range of the shrinkage force is 900N/m or more and 8000N/m or less, more preferably 1000N/m or more and 8000N/m or less, still more preferably 1100N/m or more and 8000N/m or less, still more preferably 1200N/m or more and 8000N/m or less. The upper limit is preferably 6000N/m or less, 5500N/m or less, or 4800N/m or less.
The shrinkage force F f is the shrinkage force of the polyester film in the direction parallel to the light transmission axis of the polarizing plate, and is defined as the thickness (mm) of the polyester film x the elastic modulus (N/mm 2) x the heat shrinkage (%) at 80℃for 30 minutes/100X 1000.
Here, the elastic modulus refers to the elastic modulus of the polyester film in a direction parallel to the light transmission axis of the polarizing plate. The heat shrinkage ratio is the heat shrinkage ratio of the polyester film in the direction parallel to the light transmission axis of the polarizing plate (heat shrinkage ratio in 80 ℃ C. 30 minutes heat treatment).
The shrinkage force of the polyester film in the direction parallel to the absorption axis of the polarizing plate was set to F v. The shrinkage force F v is defined as the thickness (mm) of the polyester film x the elastic modulus (N/mm 2) x the heat shrinkage (%) at 80℃after heat treatment for 30 minutes/(100X 1000). Here, the elastic modulus is the elastic modulus of the polyester film in a direction parallel to the absorption axis of the polarizing plate. The heat shrinkage ratio is the heat shrinkage ratio of the polyester film in the direction parallel to the absorption axis of the polarizing plate (heat shrinkage ratio in 80 ℃ C. 30 minutes heat treatment).
In the polyester film for protecting a polarizing plate of the present invention, F f/Fv is preferably 1.0 or more and 12.0 or less. More preferably 2.5 to 12.0. When the lower limit value of F f/Fv is less than 1.0, the warpage of the liquid crystal panel may not be sufficiently reduced. If the upper limit of F f/Fv exceeds 12.0, thermal deformation in one direction becomes large, and stress is applied to the protective film and the retardation film laminated on the surface of the polarizer opposite to the surface on which the polyester film for protecting the polarizer is laminated, which may deteriorate display quality. In addition, the stability of the film formation is lowered, and breakage may occur.
As a method of controlling the shrinkage force within the range of the above formula, there is given: and a method of re-stretching the film while controlling the winding tension of the film after the completion of the heat treatment step after the film stretching.
In the polyester film for protecting a polarizing plate of the present invention, the elastic modulus of the polyester film in the light transmission axis direction of the polarizing plate is preferably 1000 to 9000N/mm 2. The shrinkage force of the polyester film can be controlled by the elastic modulus, but in order to increase the elastic modulus of the polyester film in the transmission axis direction of the polarizing plate, it is necessary to highly orient the polyester film in the transmission axis direction of the polarizing plate and to increase crystallinity. Therefore, if the elastic modulus of the polyester film in the light transmission axis direction of the polarizing plate exceeds 9000N/mm 2, the polyester film may be easily broken, and therefore, the upper limit is preferably 9000N/mm 2, more preferably 8000N/mm 2, and further preferably 7000N/mm 2. On the other hand, when the orientation is low and the crystallinity is low, there is a concern that the film is deformed due to the roll irregularities resulting from uneven thickness when the film is wound into a roll, and the flatness is poor. Thus, the lower limit of the elastic modulus is preferably 1000N/mm 2, more preferably 1500N/mm 2, still more preferably 1800N/mm 2. The elastic modulus can be measured by the method used in examples described later.
In the polyester film for protecting a polarizing plate of the present invention, the heat shrinkage of the polyester film in the light transmission axis direction at 80℃for 30 minutes is preferably 0.10 to 5.0%. The lower limit of the heat shrinkage is preferably 0.10% or more, more preferably 0.15% or more, and most preferably 0.20% or more. The upper limit of the heat shrinkage is preferably 4.5% or less, more preferably 4.0% or less, still more preferably 3.0% or less, still more preferably 2% or less, and most preferably 1.4% or less. When the heat shrinkage is less than 0.10%, that is, in the range of 0.01 to 0.099%, it may be difficult to control the heat shrinkage without fluctuation. In order to increase the heat shrinkage to more than 5.0%, it is necessary to further lower the crystallinity and the glass transition temperature, and thus, there is a concern that defects such as poor flatness may occur. The heat shrinkage can be measured by the method used in examples described later.
The thickness of the polyester film for protecting a polarizing plate of the present invention is preferably 40 to 200. Mu.m, more preferably 40 to 100. Mu.m, still more preferably 40 to 80. Mu.m. If the thickness of the polyester film is less than 40 μm, the film tends to be broken easily, and further, the film tends to have poor flatness due to insufficient rigidity. In the case of a thin film, the elastic modulus and the heat shrinkage ratio of the polyester film in the light transmission axis direction of the polarizing plate need to be increased according to the thickness, but as described above, there is an upper limit for each parameter, and therefore, a lower limit is substantially 40 μm. In addition, when the film thickness exceeds 200 μm, the fluctuation of the elastic modulus and the heat shrinkage of the polyester film in the light transmission axis direction of the polarizing plate becomes large, and there is a concern that control thereof becomes difficult, and the cost also increases. The thickness of the polyester film can be measured by the method used in examples described later.
In the polyester film for protecting a polarizing plate of the present invention, the in-plane retardation is preferably in a specific range from the viewpoint of suppressing rainbow unevenness observed on the screen of a liquid crystal display device. The lower limit of the in-plane retardation is preferably 3000nm or more, 5000nm or more, 6000nm or more, 7000nm or more, or 8000nm or more. The upper limit of the in-plane retardation is preferably 30000nm or less, more preferably 18000nm or less, and still more preferably 15000nm or less. In particular, from the viewpoint of film formation, the in-plane retardation is preferably less than 10000nm and 9000 nm.
The retardation of the polyester film may be obtained by measuring the refractive index and the thickness in the biaxial directions, or may be obtained by using a commercially available automatic birefringence measuring apparatus such as KOBRA-21ADH (from prince measuring instruments Co., ltd.). The refractive index can be obtained by an Abbe refractometer (measurement wavelength 589 nm).
The polyester film for protecting a polarizing plate of the present invention has a ratio (Re/Rth) of the in-plane retardation (Re) to the retardation in the thickness direction (Rth) of preferably 0.2 or more, preferably 0.3 or more, preferably 0.4 or more, more preferably 0.5 or more, and still more preferably 0.6 or more. The greater the ratio (Re/Rth) of the in-plane retardation to the thickness-direction retardation, the more isotropic the birefringence becomes, and the less likely the occurrence of iridescent stains due to the observation angle becomes. In the completely uniaxial (uniaxially symmetric) film, the ratio (Re/Rth) of the retardation amount to the retardation amount in the thickness direction is 2.0, and therefore, the upper limit of the ratio (Re/Rth) of the retardation amount to the retardation amount in the thickness direction is preferably 2.0. The upper limit of Re/Rth is preferably 1.2 or less. The thickness-direction retardation is an average of the retardation obtained by multiplying 2 birefringence Δ Nxz and Δ Nyz when the film is viewed in cross section in the thickness direction by the film thickness d.
In the polyester film for protecting a polarizing plate of the present invention, the NZ coefficient of the polyester film is preferably 2.5 or less, more preferably 2.0 or less, further preferably 1.8 or less, further preferably 1.6 or less, from the viewpoint of further suppressing iridescent stains. In addition, in the completely uniaxial (uniaxially symmetric) film, the NZ coefficient is 1.0, and therefore, the lower limit of the NZ coefficient is 1.0. However, as the film becomes closer to a completely uniaxial (uniaxially symmetric) film, the mechanical strength in the direction perpendicular to the orientation direction tends to be significantly lowered, and therefore, attention is required.
The NZ coefficient is represented by |ny-nz|/|ny-nx|, where Ny means a refractive index in the slow axis direction of the polyester film, nx means a refractive index in a direction orthogonal to the slow axis (a refractive index in the fast axis direction), and NZ means a refractive index in the thickness direction. The orientation axis of the film was obtained by a molecular orientation meter (Oji Keisokukiki Co., ltd., MOA-6004 type molecular orientation meter), and the refractive indices (Ny, nx, ny > Nx) in the direction of the orientation axis and the two axes orthogonal thereto, and the refractive index (Nz) in the thickness direction were obtained by an Abbe refractive index meter (ATAGOCO., LTD., NAR-4T, measurement wavelength 589 nm). The thus obtained value is substituted into |ny-nz|/|ny-nx| to obtain the Nz coefficient.
In the polyester film of the present invention, the value of ny—nx of the polyester film is preferably 0.05 or more, more preferably 0.07 or more, still more preferably 0.08 or more, still more preferably 0.09 or more, and most preferably 0.1 or more, from the viewpoint of further suppressing iridescent stains. The upper limit is not particularly limited, but in the case of a polyethylene terephthalate film, the upper limit is preferably about 1.5.
The polyester film of the present invention can be obtained from any polyester resin. The type of the polyester resin is not particularly limited, and any polyester resin obtained by condensing a dicarboxylic acid with a diol may be used.
Examples of the dicarboxylic acid component that can be used in the production of the polyester resin include terephthalic acid, isophthalic acid, phthalic acid, 2, 5-naphthalenedicarboxylic acid, 2, 6-naphthalenedicarboxylic acid, 1, 4-naphthalenedicarboxylic acid, 1, 5-naphthalenedicarboxylic acid, dibenzoic acid, diphenoxyethane dicarboxylic acid, diphenylsulfone carboxylic acid, anthracene dicarboxylic acid, 1, 3-cyclopentanedicarboxylic acid, 1, 3-cyclohexanedicarboxylic acid, 1, 4-cyclohexanedicarboxylic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, malonic acid, dimethyl malonic acid, succinic acid, 3-diethylsuccinic acid, glutaric acid, 2-dimethylglutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, azelaic acid, dimer acid, sebacic acid, suberic acid, dodecanedicarboxylic acid, and the like.
Examples of the diol component that can be used for producing the polyester resin include ethylene glycol, propylene glycol, hexylene glycol, neopentyl glycol, 1, 2-cyclohexanedimethanol, 1, 4-cyclohexanedimethanol, decanediol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 2-bis (4-hydroxyphenyl) propane, and bis (4-hydroxyphenyl) sulfone.
The dicarboxylic acid component and the diol component constituting the polyester resin may each be 1 or 2 or more. Examples of suitable polyester resins constituting the polyester film include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and more preferably polyethylene terephthalate and polyethylene naphthalate, but these may further contain other copolymerization components. These resins are excellent in transparency and also excellent in thermal characteristics and mechanical characteristics. In particular, polyethylene terephthalate is a suitable material because it can achieve a high elastic modulus and can control the heat shrinkage more easily.
When it is necessary to highly increase the heat shrinkage of the polyester film, it is desirable to add a copolymerization component to reduce the crystallinity moderately. In addition, since the rate of elastic strain and permanent strain is high for deformation in the vicinity of the glass transition temperature or less, it is generally difficult to highly increase the heat shrinkage rate. Therefore, it is also preferable to introduce a component having a low glass transition temperature as needed. Specifically, 1, 2-propanediol, 1, 3-propanediol, and the like are mentioned.
(Imparting functional layer)
The polarizing plate using the polyester film for protecting a polarizing plate of the present invention is desirably integrated with a glass plate of a liquid crystal cell in a state where the heat shrinkage ratio of the polyester film remains, and therefore, when a functional layer such as an easy-to-adhere layer, a hard coat layer, an antiglare layer, an antireflection layer, a low reflection preventing layer, an antireflection antiglare layer, a low reflection antiglare layer, or an antistatic layer is provided, a drying temperature is set low or a method with a small thermal history such as UV irradiation or electron beam irradiation is used. In addition, when these functional layers are provided in the film-forming step of the polyester film, the polarizing plate of the present invention can be integrated with the glass plate of the liquid crystal cell without impairing the improved heat shrinkage.
The functional layers such as the easy-to-adhere layer, the hard coat layer, the antiglare layer, the antireflection layer, the low reflection preventing layer, the antireflection antiglare layer, the low reflection antiglare layer, and the antistatic layer are preferably laminated on the surface of the polyester film opposite to the surface on which the polarizing plate is laminated, and the shrinkage force F f、Fv in the state in which these functional layers are laminated has the above-described condition.
(Method for producing oriented polyester film)
The polyester film used in the present invention can be produced according to a general production method of a polyester film. For example, the following methods can be mentioned: the polyester resin is melted, extruded into a sheet shape, and molded into an unoriented polyester, which is stretched in the machine direction by a speed difference of rolls at a temperature equal to or higher than the glass transition temperature, and then stretched in the transverse direction by a tenter, and heat-treated (heat-set). Either uniaxially or biaxially stretched films. Preferably, a uniaxially stretched film which is strongly stretched mainly in the transverse direction or a uniaxially stretched film which is strongly stretched mainly in the machine direction may be slightly stretched in a direction perpendicular to the main stretching direction. MD is abbreviated as MachineDirection, and in this specification, the MD may be referred to as a film flow direction, a longitudinal direction, or a machine direction. In addition, TD is abbreviated as TransverseDirection, and is sometimes referred to as a width direction or a transverse direction in this specification.
The polyester film is preferably adjusted in film thickness, elastic modulus and heat shrinkage so that the shrinkage force F f becomes 800N/m or more and 9000N/m or less.
(Method for adjusting elastic modulus of polyester film)
The elastic modulus of the polyester film used as the polarizer protective film may be adjusted by a conventionally known method of stretching the polyester film when the direction of the transmission axis of the polarizer coincides with the MD at the time of film formation of the polyester film, and may be adjusted by a conventionally known method of stretching the polyester film when the direction of the transmission axis of the polarizer coincides with the TD at the time of film formation of the polyester film.
Specifically, when the direction is the stretching direction, the stretching ratio can be increased, and when the direction is orthogonal to the stretching direction, the stretching ratio can be set low.
(Method for adjusting Heat shrinkage of polyester film)
When the heat shrinkage ratio of the polyester film used as the protective film for the polarizing plate is in accordance with the MD of the polyester film, the heat shrinkage ratio of the MD can be adjusted by a conventionally known method of stretching the polyester film, and when the light transmission axis direction of the polarizing plate is in accordance with the TD of the polyester film, the heat shrinkage ratio of the TD can be adjusted by a conventionally known method of stretching the polyester film.
In the case of adjusting the MD heat shrinkage of the polyester film, for example, the following adjustment can be performed: a method of expanding the interval between the jig for fixing the end in the width direction of the film and the adjacent jig in the cooling process after stretching/heat fixing, thereby stretching in the MD; the adjustment can be performed by narrowing the jig interval to contract in the MD. In addition, in the case of cutting or separating the film from the jig for fixing the end portion in the width direction of the film in the cooling process after stretching/heat fixing, the force for pulling the film is adjusted so that the film is stretched or contracted in the MD, and the adjustment can be performed. In the off-line process after film formation, when the temperature is raised for the purpose of providing a functional layer or the like, the thermal shrinkage rate changes during the temperature raising and cooling, and therefore, the stretching or shrinking in the MD can be adjusted by adjusting the force for pulling the film.
In the case of adjusting the heat shrinkage ratio of the TD of the polyester film, for example, the adjustment can be performed as follows: a method of stretching in the TD by expanding the interval between a jig for fixing the end in the width direction of the film and a jig located on the opposite side in the width direction during cooling after stretching/heat fixing; the adjustment can be performed by narrowing the interval to contract along TD.
The elastic modulus and the heat shrinkage ratio of the polyester film are preferably adjusted so that the shrinkage force ratio (F f/Fv) is 1.0 or more and 12.0 or less, more preferably 2.5 or more and 12.0 or less, with respect to the shrinkage force F v.
(Method for adjusting the slope of the Main shrinkage axis of polyester film)
The slope of the principal axis of shrinkage of the polyester film used as the protective film for a polarizing plate can be adjusted in the cooling process after stretching and heat treatment of the polyester film by a tenter or in the off-line process after film formation as disclosed in PCT/JP2014/073451 (WO 2015/037527). Specifically, in the cooling step, shrinkage due to stretching and thermal stress due to cooling, which are not completely removed in the hot setting step, occur, and depending on the balance between both in the film flow direction, the shrinkage main axis is inclined due to the upstream side or downstream side. In order to reduce the gradient of the principal axis of shrinkage, it is necessary to adjust the shrinkage force in the film flow direction (the total of the shrinkage force due to stretching and the shrinkage force due to cooling) so as to be uniform in the cooling step. In order to make it uniform, it is desirable to perform shrinkage in the film flow direction in a temperature region where the shrinkage force is high, or to perform stretching in the film flow direction in a temperature region where the shrinkage force is low. The method for performing the shrinkage or stretching may be a conventionally known method. In addition, when cutting or separating the film end, shrinkage is freely performed in the width direction at a temperature region or less after cutting/separating, and the heat shrinkage rate at a temperature region or less becomes small, and therefore, attention is required.
The polarizing plate has the polyester film for protecting a polarizing plate of the present invention laminated on at least one surface of the polarizing plate. A film having no birefringence such as a TAC film, an acrylic film, or a norbornene film is preferably laminated on the other surface of the polarizing plate. Alternatively, a polarizing plate in which no film is laminated on the other surface of the polarizing plate is also preferable from the viewpoint of thickness. In the above case, the film may not be laminated on the other surface of the polarizing plate, but a coating layer may be laminated on the polarizing plate. The coating layer may be a functional layer such as a hard coat layer or a retardation film formed by coating.
When a film other than a polyester film for protecting a polarizing plate and a coating layer of the present invention are laminated on a polarizing plate, the film other than the polyester film for protecting a polarizing plate, the shrinkage force of the coating layer, and the film other than the polyester film for protecting a polarizing plate, in the direction parallel to the light transmission axis of the polarizing plate, and the shrinkage force of the coating layer, in the direction parallel to the absorption axis of the polarizing plate, are each preferably not more than the value of F f of the polyester film for protecting a polarizing plate, and more preferably not more than the value of F v of the polyester film for protecting a polarizing plate. The shrinkage force of the film other than the polyester film for protecting a polarizing plate and the coating layer in the direction parallel to the light transmission axis of the polarizing plate, and the shrinkage force of the film other than the polyester film for protecting a polarizing plate and the coating layer in the direction parallel to the absorption axis of the polarizing plate are preferably 250N/m or less, more preferably 200N/m or less. The shrinkage force of the film or coating layer other than the polyester film for protecting the polarizing plate can be measured in the same manner as in the case of the polyester film. Namely, the film or coating layer has a thickness (mm) x elastic modulus (N/mm 2) x heat shrinkage (%) at 80℃for 30 minutes/100X 1000.
Industrially, a polarizing plate is obtained by laminating a long product of a polarizing plate and a long product of a polyester film for protecting a polarizing plate in a roll-to-roll manner with an adhesive. Further, the polarizing plate is generally manufactured by stretching in the machine direction, and thus has an absorption axis in the MD and a transmission axis in the TD.
Therefore, from the viewpoint of industrially producing a polarizing plate, the polyester film for protecting a polarizing plate of the present invention is preferably the following (1) or (2).
(1) The shrinkage force F TD of the TD of the polyester film is more than 800N/m and less than 9000N/m.
Wherein the shrinkage force F TD (N/m) is the thickness (mm) of the polyester film multiplied by the elastic modulus (N/mm 2) multiplied by the heat shrinkage (%) of 80 ℃ after 30 minutes heat treatment, 100X 1000. Here, the elastic modulus and the heat shrinkage ratio are the elastic modulus and the heat shrinkage ratio of TD of the polyester film, respectively.
(2) The ratio (F TD/FMD) of the shrinkage force F TD of the TD of the polyester film to the shrinkage force F MD of the MD of the polyester film is preferably 2.5 to 12.0.
Wherein the shrinkage force F MD (N/m) is the thickness (mm) of the polyester film multiplied by the elastic modulus (N/mm 2) multiplied by the heat shrinkage (%) of 80 ℃ after 30 minutes heat treatment, 100X 1000. Here, the elastic modulus and the heat shrinkage ratio are the elastic modulus in MD and the heat shrinkage ratio in MD of the polyester film, respectively.
In the polyester film for protecting a polarizing plate of the present invention, it is preferable that the direction in which the heat shrinkage rate of the polyester film becomes maximum is substantially parallel to TD.
The substantially parallel state means that the absolute value of the angle between the direction in which the heat shrinkage of the polyester film is maximum and the TD direction (the gradient of the heat shrinkage) is allowed to be 15 degrees or less. The slope of the heat shrinkage is preferably 12 degrees or less, more preferably 10 degrees or less, further preferably 8 degrees or less, further preferably 6 degrees or less, particularly preferably 4 degrees or less, and most preferably 2 degrees or less. The smaller the slope of the heat shrinkage, the more preferable, and therefore, the lower limit is 0 degrees.
When the ratio (F TD/FMD) of the shrinkage force F TD of the TD of the polyester film to the shrinkage force F MD of the MD of the polyester film is 2.5 to 12.0, the absolute value of the angle between the direction in which the thermal shrinkage rate of the polyester film is maximum and the TD is 40 degrees or less, and the warpage of the liquid crystal panel can be reduced. The angle is preferably 35 degrees or less.
As described above, in the case of industrially manufacturing a polarizing plate in the form of a roll-to-roll or the like, F TD corresponds to F f, and therefore, the preferable range of F TD is the same as that of F f. Since F TD/FMD corresponds to F f/Fv, the preferable ranges thereof are the same. The "elastic modulus of the TD of the polyester film" corresponds to the "elastic modulus of the polyester film in the light transmission axis direction of the polarizing plate", and therefore, the preferable ranges of the two are the same. The "heat shrinkage ratio of the TD of the polyester film when heat-treated at 80℃for 30 minutes" corresponds to the "heat shrinkage ratio of the polyester film when heat-treated at 80℃for 30 minutes" in the light transmission axis direction of the polarizing plate, and therefore, the preferable ranges thereof are the same.
The liquid crystal display device includes at least: a backlight light source; and a liquid crystal cell disposed between the 2 polarizing plates. At least one of the 2 polarizing plates is preferably a polarizing plate in which the polyester film for protecting a polarizing plate of the present invention is a polarizing plate protecting film. Both of the foregoing 2 polarizing plates of the liquid crystal display device may use the polarizing plate of the present invention.
The polyester film for protecting a polarizing plate of the present invention is preferably used in the position of the polarizing plate protecting film on the light source side, starting from the polarizing plate of the polarizing plate on the visible side and/or from the polarizing plate of the polarizing plate on the light source side.
In general, a liquid crystal display device has a rectangular shape (2 polarizing plates used in the liquid crystal display device are also rectangular), and one polarizing plate has a long side parallel to an absorption axis and the other polarizing plate has a long side parallel to a light transmission axis, and the absorption axes are arranged in a perpendicular relationship to each other. In general, a polarizing plate having a long side parallel to the absorption axis is used as a visible side polarizing plate of a liquid crystal display device, and a polarizing plate having a long side parallel to the transmission axis is used as a light source side polarizing plate of a liquid crystal display device. From the viewpoint of suppressing warpage of the liquid crystal panel, it is preferable to use at least the polarizing plate of the present invention as a polarizing plate having a long side in parallel relation to the light transmission axis. In addition, it is also preferable to use the polarizing plate of the present invention for both of the polarizing plate having a long side in parallel relation to the light transmission axis and the polarizing plate having a long side in parallel relation to the absorption axis.
Examples
The present invention will be described more specifically with reference to examples, but the present invention is not limited to the examples described below, and can be modified and implemented as appropriate within the scope of the gist of the present invention, and they are included in the scope of protection of the present invention.
(1) Force of contraction F f
The shrinkage force F f of the polyester film was calculated by the following formula. The thickness, elastic modulus, and heat shrinkage of the polyester film were measured values described below. The elastic modulus is the elastic modulus of the polyester film in a direction parallel to the transmission axis of the polarizer. The heat shrinkage is the heat shrinkage of the polyester film in a direction parallel to the transmission axis of the polarizer.
Shrinkage force F f (N/m) =thickness (mm) x elastic modulus (N/mm 2) x heat shrinkage (%) of the polyester film after 30 minutes heat treatment at 80 ℃ per 100 x 1000
(2) Force of contraction F v
The shrinkage force F v of the polyester film was calculated by the following formula. The thickness, elastic modulus, and heat shrinkage of the polyester film were measured values described below. The elastic modulus is the elastic modulus of the polyester film in a direction parallel to the absorption axis of the polarizer. The heat shrinkage is the heat shrinkage of the polyester film in a direction parallel to the absorption axis of the polarizer.
Shrinkage force F v (N/m) =thickness (mm) x elastic modulus (N/mm 2) x heat shrinkage (%) of the polyester film after 30 minutes heat treatment at 80 ℃ per 100 x 1000
(3) Film thickness
The thickness (mm) of the polyester film was measured by an electrometer (Fine Liu off co., miritoron D) after standing at 25 ℃ for 168 hours under 50RH%, and the unit was converted into mm.
(4) Elastic modulus of polyester film
The elastic modulus of the polyester film was evaluated by a dynamic viscoelasticity measuring device (DMS 6100) manufactured by Seiko Instruments Inc. in accordance with JIS-K7244 (DMS) after standing at 25℃for 168 hours under 50 RH%. Under the conditions of a stretching mode, a driving frequency of 1Hz, a distance between chucks of 5mm and a heating rate of 2 ℃/min, the temperature dependence at 25-120 ℃ is measured, and the average storage modulus at 30-100 ℃ is taken as the elastic modulus. In this way, the elastic modulus of the polyester film in the direction parallel to the transmission axis of the polarizer and the elastic modulus of the polyester film in the direction parallel to the absorption axis of the polarizer were measured for the polyester film. The measurement was performed by using a single polyester film (a single polyester film for protecting a polarizing plate).
(5) Polyester film heat shrinkage and heat shrinkage gradient
After the polyester film was allowed to stand at 25℃for 168 hours in a 50RH% environment, a circle having a diameter of 80mm was drawn, and the diameter of the circle was measured at 1 degree intervals by an Image measuring apparatus (Image measuring IM6500 manufactured by KEYENCE Co., ltd.) as the length before treatment. Then, after heat treatment was performed for 30 minutes in a gill aging oven set at 80 ℃, the heat treatment was performed for 10 minutes in an atmosphere set at 25 ℃ at room temperature, and the heat treatment was evaluated at 1 ° intervals by the same method as before, to obtain a length after the treatment. The treatment polyester film was carried out alone (the polarizing plate protective polyester film alone).
The heat shrinkage was evaluated for each angle by the following calculation formula.
Heat shrinkage = (length before treatment-length after treatment)/length before treatment×100
Thus, the heat shrinkage of the polyester film in the direction parallel to the transmission axis of the polarizer and the heat shrinkage of the polyester film in the direction parallel to the absorption axis of the polarizer were obtained.
Among the above, 360 ° was evaluated at 1 ° intervals, and the direction in which the heat shrinkage rate was the greatest was specified, and the absolute value of the angle between this direction and the light transmission axis direction of the polarizing plate was taken as the gradient of the heat shrinkage rate. The slope of the heat shrinkage is defined by a narrow angle from the transmission axis direction of the polarizing plate, and is in the range of 0 to 90 °.
(6) Warpage of liquid crystal panel
The liquid crystal panels produced in each example and comparative example were subjected to heat treatment with a gill aging oven set at 80 ℃ for 30 minutes, then cooled in an atmosphere set at room temperature of 25 ℃ and 50% rh for 30 minutes, and then the convex side was set down, placed on a horizontal plane, and the height at 4 was measured with a tape measure, and the maximum value was taken as the warpage amount. The amount of warpage was evaluated as follows.
O: 0mm or more and less than 2.0mm
Delta: 2.0mm or more and 3.0mm or less
X: exceeding 3.0mm
(7) Refractive index of polyester film
The slow axis direction of the film was determined by a molecular orientation meter (Oji Keisokukiki Co., ltd., MOA-6004 type molecular orientation meter), and the film was cut into a rectangle of 4 cm. Times.2 cm so that the slow axis direction was parallel to the long side of the sample for measurement, and the rectangle was used as the sample for measurement. For this sample, the refractive index of the two orthogonal axes (refractive index in the slow axis direction: ny, fast axis (refractive index in the direction orthogonal to the slow axis direction): nx) and refractive index in the thickness direction (Nz) were obtained by an Abbe refractometer (ATAGO CO., LTD. Co., NAR-4T, measurement wavelength 589 nm). These values were used to determine the NZ coefficient.
The retardation is defined by the product (Δnxy×d) of the refractive index anisotropy (Δnxy= |nx-ny|) of two orthogonal axes on the film and the film thickness d (nm), and is a scale indicating optical isotropy and anisotropy. The anisotropy of refractive index (Δnxy) of the biaxial was determined by the following method. The slow axis direction of the film was determined by a molecular orientation meter (Oji Keisokukiki Co., ltd., MOA-6004 type molecular orientation meter), and the film was cut into a rectangle of 4 cm. Times.2 cm so that the slow axis direction was parallel to the long side of the sample for measurement, and the rectangle was used as the sample for measurement. For this sample, the refractive index of the two orthogonal axes (refractive index in the slow axis direction: ny, refractive index in the direction orthogonal to the slow axis direction: nx) and the refractive index in the thickness direction (Nz) were obtained by an Abbe refractometer (ATAGO CO., LTD. Co., NAR-4T, measurement wavelength 589 nm), and the absolute value of the refractive index difference in the two axes (|Nx-Ny|) was used as the anisotropy of the refractive index (. DELTA.Nxy). The thickness D (nm) of the film was measured by an electrometer (Fine Liu off co., product, miritoron 1245D) and the unit was converted into nm. The retardation (Re) was obtained from the product (DeltaNxy×d) of the anisotropy of refractive index (DeltaNxy) and the thickness d (nm) of the film.
(8) Thickness direction retardation (Rth)
The thickness-direction retardation is a parameter indicating an average of retardation amounts obtained by multiplying 2 birefringence Δ Nxz (= |nx-nz|) and Δ Nyz (= |ny-nz|) in the cross section in the film thickness direction by the film thickness d, respectively. By the same method as the measurement of retardation, nx, ny, nz and film thickness d (nm) were obtained, and the average value of (Δ Nxz ×d) and (Δ Nyz ×d) was calculated to obtain the retardation in the thickness direction (Rth).
PREPARATION EXAMPLE 1-polyester A
The esterification reaction tank was warmed up, and 86.4 parts by mass of terephthalic acid and 64.6 parts by mass of ethylene glycol were charged at 200℃and 0.017 parts by mass of antimony trioxide, 0.064 parts by mass of magnesium acetate tetrahydrate and 0.16 parts by mass of triethylamine as a catalyst were charged while stirring. Then, the temperature was raised under pressure, the esterification reaction was carried out under pressure at 0.34MPa and 240℃to return the esterification reaction tank to normal pressure, and 0.014 parts by mass of phosphoric acid was added. Further, the temperature was raised to 260℃over 15 minutes, and 0.012 parts by mass of trimethyl phosphate was added thereto. Then, after 15 minutes, the resultant esterification reaction product was transferred to a polycondensation reaction tank, and after 15 minutes, the polycondensation reaction was carried out at 280℃under reduced pressure.
After the completion of the polycondensation reaction, the mixture was filtered through a NASLON-unit filter having a 95% cutoff diameter of 5. Mu.m, extruded into strands from a nozzle, cooled and solidified with cooling water previously subjected to filtration (pore diameter: 1 μm or less), and cut into pellets. The intrinsic viscosity of the obtained polyethylene terephthalate resin (A) was 0.62dl/g, and the polyethylene terephthalate resin was substantially free of inactive particles and internal precipitated particles. (hereinafter abbreviated as PET (A))
PREPARATION EXAMPLE 2-polyester B
10 Parts by mass of dried ultraviolet absorber (2, 2' - (1, 4-phenylene) bis (4H-3, 1-benzoxazin-4-one) and 90 parts by mass of PET (A) (intrinsic viscosity of 0.62 dl/g) containing no particles were mixed, and a kneading extruder was used to obtain ultraviolet absorber-containing polyethylene terephthalate resin (B) (hereinafter abbreviated as PET (B))
Preparation example 3 preparation of adhesion modified coating liquid
The water-dispersible sulfonate-metal salt-containing copolyester resin having a composition of 46 mol% of terephthalic acid, 46 mol% of isophthalic acid and 8 mol% of sodium 5-sulfoisophthalate as a dicarboxylic acid component (based on the entire dicarboxylic acid component), 50 mol% of ethylene glycol and 50 mol% of neopentyl glycol as a diol component (based on the entire diol component) was prepared by a conventional method. Then, after mixing 51.4 parts by mass of water, 38 parts by mass of isopropyl alcohol, 5 parts by mass of n-butyl cellosolve and 0.06 parts by mass of a nonionic surfactant, stirring by heating to 77 ℃, adding 5 parts by mass of the above water-dispersible sulfonate-group-containing copolymerized polyester resin, continuing stirring until the blocks of the resin disappear, and cooling the resin aqueous dispersion to room temperature to obtain a uniform water-dispersible copolymerized polyester resin liquid having a solid content of 5.0% by mass. Further, 3 parts by mass of aggregate silica particles (manufactured by FUJI SILYSIA CHEMICAL ltd. SILYSIA 310) were dispersed in 50 parts by mass of water, and then 0.54 part by mass of an aqueous dispersion of SILYSIA 310 was added to 99.46 parts by mass of the water-dispersible copolyester resin liquid, followed by stirring and adding 20 parts by mass of water, to obtain an adhesive modified coating liquid.
Example 1
Production of polyester film 1 for protecting polarizing plate
90 Parts by mass of PET (A) resin pellets containing no particles and 10 parts by mass of PET (B) resin pellets containing an ultraviolet absorber, which were raw materials for an intermediate layer of a base film, were dried at 135℃for 6 hours under reduced pressure (1 Torr), and then fed to an extruder 2 (for an intermediate layer II), and PET (A) was dried by a conventional method, and fed to an extruder 1 (for an outer layer I and an outer layer III), respectively, and dissolved at 285 ℃. The 2 polymers were each filtered through a stainless steel sintered filter medium (nominal filtration accuracy 10 μm particles 95% cut-off), laminated with 2 kinds of 3-layer joint blocks, extruded from a nozzle into a sheet, and then wound on a casting drum (casting drum) having a surface temperature of 30℃by an electrostatic casting method to be cooled and solidified, thereby producing an unstretched film. At this time, the ratio of the thicknesses of the layer I, layer II, and layer III was 10:80:10, the discharge amount of each extruder was adjusted.
Then, the adhesion-modified coating liquid was applied to both sides of the unstretched PET film by a reverse roll method so that the coating amount after drying was 0.08g/m 2, and then dried at 80℃for 20 seconds.
The unstretched film having the coating layer formed thereon was introduced into a tenter stretcher, and the end of the film was introduced into a hot air zone at 105℃while being held by a jig, and stretched to 4.0 times in TD. Subsequently, the film cooled to 100℃was stretched by 1.0% in the width direction after heat treatment at 180℃for 30 seconds, and then, the film cooled to 60℃was pulled by a tension of 350N/m by opening a jig for fixing both ends of the film, and a large-diameter roll of a uniaxially oriented PET film having a film thickness of about 80 μm was collected, and the obtained large-diameter roll was divided by 3 equal portions to obtain 3 slit rolls (L (left side), C (center), R (right side)). The polyester film 1 for protecting a polarizing plate was obtained from a slit roll located at R. The direction of maximum heat shrinkage of the polyester film 1 for protecting a polarizing plate deviates from TD by 7.0 degrees.
< Manufacturing of liquid Crystal Panel >)
On one side of a polarizing plate including PVA, iodine, and boron, the polarizing plate protective polyester film 1 is attached so that the light transmission axis of the polarizing plate is parallel to the TD of the polarizing plate protective polyester film 1. Further, a TAC film (80 μm thick, manufactured by Fuji film Co., ltd.) was adhered to the opposite surface of the polarizing plate to prepare a light source side polarizing plate.
The liquid crystal panel was taken out from a 46-inch IPS type liquid crystal television in which a glass substrate having a thickness of 0.4mm was used for the liquid crystal cell. The light source side polarizing plate was peeled off from the liquid crystal panel, and instead of this, the light source side polarizing plate produced by the above was stuck to the liquid crystal cell via PSA so that the transmission axis of the polarizing plate was aligned with the transmission axis direction (parallel to the horizontal direction) of the light source side polarizing plate before peeling off.
The light source-side polarizing plate was attached to the liquid crystal cell so that the polarizer protective mylar 1 and the liquid crystal cell were on the distal side (opposite side). The visible-side polarizing plate is formed by laminating TAC films on both surfaces of a polarizing plate, and is attached to a liquid crystal cell so that the absorption axis direction of the polarizing plate is parallel to the horizontal direction.
Example 2
Production of polyester film 2 for protecting polarizing plate
A polyester film 2 for protecting a polarizing plate was obtained in the same manner as the polyester film 1 for protecting a polarizing plate, except that the film cooled to 100 ℃ was stretched by 1.5% in the width direction in the film formation of the polyester film 1 for protecting a polarizing plate of example 1. For the polyester film 2 for protecting a polarizing plate, the deviation in the direction from TD, in which the heat shrinkage rate becomes maximum, was 6.5 degrees.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 1, except that the polarizing plate protective polyester film 1 was replaced with the polarizing plate protective polyester film 2 in example 1.
Example 3
Production of polyester film 3 for protecting polarizing plate
A polarizing plate protective film 3 was obtained in the same manner as in the polarizing plate protective polyester film 1 of example 1 except that the film cooled to 100 ℃ was stretched by 1.7% in the width direction in the film formation of the polarizing plate protective polyester film 1. For the polyester film 3 for protecting a polarizing plate, the deviation in the direction from TD, in which the heat shrinkage rate becomes maximum, was 5.3 degrees.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 1 except that the polarizing plate protective polyester film 1 was replaced with the polarizing plate protective polyester film 3 in example 1.
Example 4
Production of polyester film 4 for protecting polarizing plate
In the film formation of the polyester film 1 for protecting a polarizing plate of example 1, a film cooled to 100℃was stretched 2.0% in the width direction, and a hard coat layer coating liquid was applied to one side of the polyester film at a time before heat treatment at 180℃for 30 seconds after stretching 4 times in the TD, to obtain a polarizing plate protecting film 4 in the same manner as the polyester film 1 for protecting a polarizing plate. For the polyester film 4 for protecting a polarizing plate, the deviation in the direction from TD, in which the heat shrinkage rate becomes maximum, was 4.8 degrees.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 1 except that the polarizing plate protective polyester film 1 was replaced with the polarizing plate protective polyester film 4 in example 1.
Example 5
Production of polyester film 5 for protecting polarizing plate
A polyester film for protecting a polarizing plate 5 was obtained in the same manner as the polyester film for protecting a polarizing plate 4 except that the rotation speed of the casting roll was adjusted so that the thickness of the stretched film was 160. Mu.m. For the polyester film 5 for protecting a polarizing plate, the deviation in the direction from TD, in which the heat shrinkage rate becomes maximum, was 4.8 degrees.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 1 except that the polarizing plate protective polyester film 1 was replaced with the polarizing plate protective polyester film 5 in example 1.
Example 6
Production of polyester film 6 for protecting polarizing plate
A polarizing plate protective polyester film 6 was obtained in the same manner as in the polarizing plate protective polyester film 1 of example 1 except that the film cooled to 100 ℃ was stretched by 1.5% in the flow direction in the film formation of the polarizing plate protective polyester film 1. For the polyester film 6 for protecting a polarizing plate, the deviation in the direction from MD in which the heat shrinkage ratio was the greatest was 9.0 degrees.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 1, except that the light source-side polarizing plate of example 1 was produced by using the polarizing plate protective polyester film 6 instead of the polarizing plate protective polyester film, and bonding the polarizing plate so that the transmission axis of the polarizing plate and the MD of the polarizing plate protective polyester film 6 became parallel.
Example 7
Production of polyester film 7 for protecting polarizing plate
A polarizing plate protective polyester film 7 was obtained in the same manner as in the polarizing plate protective polyester film 1 of example 1 except that the film cooled to 100 ℃ was stretched by 1.7% in the flow direction in the film formation of the polarizing plate protective polyester film 1. For the polyester film 7 for protecting a polarizing plate, the deviation in the direction from MD in which the heat shrinkage rate was the greatest was 8.3 degrees.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 6 except that the polarizing plate protective polyester film 6 was replaced with the polarizing plate protective polyester film 7 in example 6.
Example 8
Production of polyester film 8 for protecting polarizing plate
A polarizing plate protective polyester film 8 was obtained in the same manner as the polarizing plate protective polyester film 1 in example 1 except that the film cooled to 100 ℃ was stretched by 2.0% in the flow direction in the film formation of the polarizing plate protective polyester film 1. For the polyester film 8 for protecting a polarizing plate, the deviation in the direction in which the heat shrinkage rate becomes maximum was 7.0 degrees from MD.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 6 except that the polarizing plate protective polyester film 6 was replaced with the polarizing plate protective polyester film 8 in example 6.
Example 9
Production of polyester film 9 for protecting polarizing plate
A polyester film for protecting a polarizing plate 9 was obtained in the same manner as the polyester film for protecting a polarizing plate 8 except that the rotation speed of the casting roll was adjusted so that the thickness of the stretched film was 160. Mu.m. For the polyester film 9 for protecting a polarizing plate, the deviation in the direction in which the heat shrinkage rate becomes maximum was 7.0 degrees from MD.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 6 except that the polarizing plate protective polyester film 6 was replaced with a polarizing plate protective polyester film 9 in example 6.
Example 10
Production of polyester film 10 for protecting polarizing plate
A polarizer protective film 10 was obtained in the same manner as in the polarizer protective polyester film 6 except that the stretching operation in the TD was changed to stretching operation in the MD by 4.0 times and stretching operation in the TD by 1.0 times. For the polyester film 10 for protecting a polarizing plate, the deviation in the direction from MD in which the heat shrinkage rate becomes maximum was 8.7 degrees.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 6 except that the polarizing plate protective polyester film 6 was replaced with the polarizing plate protective polyester film 10 in example 6.
Example 11
Production of polyester film 11 for protecting polarizing plate
A polarizing plate protective polyester film 11 was obtained in the same manner as in the polarizing plate protective polyester film 10 except that the film cooled to 100 ℃ was stretched by 1.7% in the flow direction in the film formation of the polarizing plate protective polyester film 10 of example 10. For the polyester film 11 for protecting a polarizing plate, the deviation in the direction from MD in which the heat shrinkage ratio was the greatest was 7.5 degrees.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 10 except that in example 10, the polarizing plate protective polyester film 10 was replaced with the polarizing plate protective polyester film 11.
Example 12
Production of polyester film 12 for protecting polarizing plate
A polarizing plate protective polyester film 12 was obtained in the same manner as in the polarizing plate protective polyester film 10 except that the film cooled to 100 ℃ was stretched 5.0% in the width direction in the film formation of the polarizing plate protective polyester film 10 of example 10. For the polyester film 12 for protecting a polarizing plate, the deviation in the direction from TD, in which the heat shrinkage rate becomes maximum, was 1.8 degrees.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 1 except that the polarizing plate protective polyester film 1 was replaced with the polarizing plate protective polyester film 12 in example 1.
Example 13
Production of polyester film 13 for protecting polarizing plate
A polyester film 13 for protecting a polarizing plate was obtained in the same manner as the polyester film 4 for protecting a polarizing plate except that the rotation speed of the casting roll was adjusted so that the thickness of the stretched film was 60. Mu.m. The direction of maximum heat shrinkage was deviated from TD by 4.8 degrees for the polarizer protective polyester film 13.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 1 except that the polarizing plate protective polyester film 1 was replaced with the polarizing plate protective polyester film 13 in example 1.
Example 14
Production of polyester film 14 for protecting polarizing plate
In the cooling step after stretching 1.7% in the width direction, the film was passed without changing the width of the jig for fixing the both ends of the film, and a polarizer protective film 14 was obtained in the same manner as in the polarizer protective film 3. The direction of maximum heat shrinkage of the polyester film 14 for protecting a polarizing plate was deviated from TD by 33.0 degrees.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 3, except that the polarizer protective film 1 was replaced with the polarizer protective film 14.
Comparative example 1
Production of polyester film 15 for protecting polarizing plate
The polarizing plate protective film 15 was obtained in the same manner as the polarizing plate protective film 1 except that the rotation speed of the casting roll was adjusted so that the thickness of the stretched film became 200 μm, and the film was passed without changing the widths of the jigs for fixing the both ends of the film in the cooling step after stretching and heat fixing. For the polyester film 15 for protecting a polarizing plate, the deviation in the direction from MD in which the heat shrinkage ratio becomes maximum was 20.0 degrees.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 1 except that the polarizer protective film 1 was replaced with the polarizer protective film 15, and the light source side polarizing plate was produced by bonding the polarizer so that the transmission axis of the polarizer and the MD of the polarizer protective film became parallel.
Comparative example 2
Production of polyester film 16 for protecting polarizing plate
In the cooling step after stretching/heat fixing, the polarizer protective film 16 was obtained in the same manner as in the polarizer protective film 1 except that the clamps for fixing both ends of the film were released at 95 ℃ without performing a 1.0% stretching treatment in the width direction. For the polyester film 16 for protecting a polarizing plate, the deviation in the direction in which the heat shrinkage ratio becomes maximum was 1.0 degree from MD.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 1 except that the polarizer protective film 1 was replaced with the polarizer protective film 16, and the light source side polarizing plate was produced by bonding the polarizer so that the transmission axis of the polarizer and the MD of the polarizer protective film became parallel.
Comparative example 3
Production of polyester film 17 for protecting polarizing plate
A polyester film 17 for protecting a polarizing plate was obtained in the same manner as the polyester film 1 for protecting a polarizing plate except that the rotation speed of the casting roll was adjusted so that the thickness of the film after stretching was 50. Mu.m. For the polyester film 17 for protecting a polarizing plate, the deviation in the direction in which the heat shrinkage ratio becomes maximum was 7.0 degrees from TD.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 1 except that the polarizing plate protective polyester film 1 was replaced with the polarizing plate protective polyester film 17 in example 1.
Comparative example 4
Production of polyester film 18 for protecting polarizing plate
A polyester film 18 for protecting a polarizing plate was obtained in the same manner as the polyester film 11 for protecting a polarizing plate except that the rotation speed of the casting roll was adjusted so that the thickness of the stretched film was 160. Mu.m. For the polyester film 18 for protecting a polarizing plate, the deviation in the direction from MD in which the heat shrinkage rate becomes maximum was 6.5 degrees.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 11 except that the polarizing plate protective polyester film 11 was replaced with the polarizing plate protective polyester film 18 in example 11.
Comparative example 5
Production of polyester film 19 for protecting polarizing plate
A polarizing plate protective polyester film 19 was obtained in the same manner as the polarizing plate protective polyester film 1 except that the rotational speed of the casting roll was adjusted so that the thickness of the stretched film was 160 μm, and the film cooled to 100℃was stretched by 1.0% in the flow direction in the film production of the polarizing plate protective polyester film 1 of example 1. For the polyester film 19 for protecting a polarizing plate, the deviation in the direction from MD in which the heat shrinkage rate becomes maximum was 11.0 degrees.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 1, except that the light source-side polarizing plate of example 1 was produced by using the polarizing plate protective polyester film 19 instead of the polarizing plate protective polyester film, and bonding the polarizing plate so that the light transmission axis of the polarizing plate and the TD of the polarizing plate protective polyester film 19 were parallel.
Comparative example 6
Production of polyester film 20 for protecting polarizing plate
A polyester film for protecting a polarizing plate 20 was obtained in the same manner as the polyester film for protecting a polarizing plate 19 except that the rotation speed of the casting roll was adjusted so that the thickness of the film after stretching was 80. Mu.m. For the polyester film 20 for protecting a polarizing plate, the deviation in the direction from MD in which the heat shrinkage rate becomes maximum was 11.0 degrees.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in comparative example 5 except that the polarizing plate protective polyester film 19 was replaced with the polarizing plate protective polyester film 20 in comparative example 5.
Comparative example 7
Production of polyester film 21 for protecting polarizing plate
A polarizer protective film 21 was obtained in the same manner as the polarizer protective film 20. For the polyester film 21 for protecting a polarizing plate, the deviation in the direction from MD in which the heat shrinkage rate becomes maximum was 11.0 degrees.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 1, except that the light source-side polarizing plate of example 1 was produced by using the polarizing plate protective polyester film 21 instead of the polarizing plate protective polyester film 1 and bonding the polarizing plate so that the transmission axis of the polarizing plate and the MD of the polarizing plate protective polyester film 21 become parallel.
Comparative example 8
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 1, except that the polarizer protective film 15 was attached so that the light transmission axis of the polarizer and the TD of the polarizer protective film were parallel to each other, to thereby produce a light source side polarizing plate.
Comparative example 9
Production of polyester film 22 for protecting polarizing plate
A polarizing plate protective polyester film 22 was obtained in the same manner as the polarizing plate protective polyester film 1 except that the rotational speed of the casting roll was adjusted so that the thickness of the stretched film was 160 μm, and the film cooled to 100℃was stretched by 1.0% in the flow direction in the film production of the polarizing plate protective polyester film 1 of example 1. For the polyester film 22 for protecting a polarizing plate, the deviation in the direction from MD in which the heat shrinkage rate becomes maximum was 11.0 degrees.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 1, except that the light source-side polarizing plate of example 1 was produced by using the polarizing plate protective polyester film 22 instead of the polarizing plate protective polyester film 1 and bonding the polarizing plate so that the transmission axis of the polarizing plate and the MD of the polarizing plate protective polyester film 22 became parallel.
Comparative example 10
Production of polyester film 23 for protecting polarizing plate
A polarizing plate protective polyester film 23 was obtained in the same manner as in the polarizing plate protective polyester film 10 except that the film cooled to 100 ℃ was stretched by 2.0% in the flow direction in the film formation of the polarizing plate protective polyester film 10 of example 10. For the polyester film 23 for protecting a polarizing plate, the deviation in the direction from MD in which the heat shrinkage ratio became maximum was 4.5 degrees.
< Manufacturing of liquid Crystal Panel >)
A liquid crystal panel was produced in the same manner as in example 10 except that the polarizing plate protective polyester film 10 was replaced with the polarizing plate protective polyester film 23 in example 10.
TABLE 1
From the results shown in table 1, it was confirmed that the polarizing plate using the polarizing plate protective film of the present invention can suppress warpage of the panel as compared with the polarizing plate of the comparative example.
(Example 1A-example 5A, example 13A)
In addition to using the polarizing plates having the same configuration as the light source side polarizing plates used in the respective examples 1 to 5 and 13 as the light source side polarizing plates and the visible side polarizing plates, the evaluation was performed separately in the same manner as in examples 1 to 5 and 13, and in this case, in the same manner as in examples 1 to 5 and 13 of table 1, good results (o) were obtained in the evaluation of warpage of the panel. The light source side polarizing plate and the visible side polarizing plate were attached to the liquid crystal cell so that the polarizer protective polyester film and the liquid crystal cell were on the distal side (opposite side).
(Example 1B-example 5B, example 13B)
In examples 1A to 5A and 13A, the evaluation was performed separately in the same manner as in examples 1A to 5A and 13A except that a TAC film was not used as the polarizing plate protective film on the liquid crystal cell side, and in this case, good results (o) were obtained in the evaluation of warpage of the panel in the same manner as in examples 1A to 5A and 13A.
Industrial applicability
According to the present invention, there may be provided: a polarizer protective film, a polarizing plate and a liquid crystal display device capable of suppressing warpage of a liquid crystal panel.
Claims (34)
1. A polyester film for protecting a polarizing plate, which is laminated on one surface of a polarizing plate and satisfies the following characteristics (1), (2) and (3),
(1) The shrinkage force F f of the polyester film in the direction parallel to the light transmission axis of the polarizing plate is 800N/m or more and 9000N/m or less, wherein the shrinkage force F f is the thickness of the polyester film x the elastic modulus x the heat shrinkage percentage by 30 minutes heat treatment at 80 ℃ is ≡100 x 1000, the elastic modulus is the elastic modulus of the polyester film in the direction parallel to the light transmission axis of the polarizing plate, the heat shrinkage percentage is the heat shrinkage percentage of the polyester film in the direction parallel to the light transmission axis of the polarizing plate, the shrinkage force F f is N/m, the thickness of the polyester film is mm, the elastic modulus is N/mm 2,
(2) The ratio F f/Fv of the shrinkage force F f of the polyester film in the direction parallel to the light transmission axis of the polarizing plate to the shrinkage force F v of the polyester film in the direction parallel to the absorption axis of the polarizing plate is 2.5 to 12.0, wherein the shrinkage force F v is the thickness of the polyester film x the elastic modulus x the heat shrinkage percentage of the polyester film after heat treatment at 80 ℃ for 30 minutes ≡100 x 1000, wherein the elastic modulus is the elastic modulus of the polyester film in the direction parallel to the absorption axis of the polarizing plate, the heat shrinkage percentage is the heat shrinkage percentage of the polyester film in the direction parallel to the absorption axis of the polarizing plate, the shrinkage force F v is N/m, the thickness of the polyester film is mm, the elastic modulus is N/mm 2,
(3) The elastic modulus of the polyester film in a direction parallel to the transmission axis of the polarizing plate is 1500N/mm 2 or more and 7000N/mm 2 or less.
2. A polyester film for protecting a polarizing plate, which is laminated on one surface of a polarizing plate and satisfies the following characteristics (1), (2) and (3),
(1) The shrinkage force F TD of the TD of the polyester film is more than 800N/m and less than 9000N/m, wherein the shrinkage force F TD is the thickness of the polyester film multiplied by the elastic modulus multiplied by the heat shrinkage rate%100×1000 after 30 minutes of heat treatment at 80 ℃, the elastic modulus is the elastic modulus of the TD of the polyester film, the heat shrinkage rate is the heat shrinkage rate of the TD of the polyester film, the shrinkage force F TD is N/m, the thickness of the polyester film is mm, the elastic modulus is N/mm 2,
(2) The ratio F TD/FMD of the shrinkage force F TD of the TD of the polyester film to the shrinkage force F MD of the MD of the polyester film is 2.5 to 12.0, wherein the shrinkage force F MD is the thickness of the polyester film x the thermal shrinkage rate%100 x 1000 of the heat treatment at 80 ℃ for 30 minutes, the elastic modulus is the elastic modulus of the MD of the polyester film, the thermal shrinkage rate is the thermal shrinkage rate of the MD of the polyester film, the shrinkage force F MD is N/m, the thickness of the polyester film is mm, the elastic modulus is N/mm 2,
(3) The elastic modulus of the polyester film in the TD direction is more than 1500N/mm 2 and less than 7000N/mm 2.
3. The polyester film for protecting a polarizing plate according to claim 1, wherein an absolute value of an angle between a direction in which a heat shrinkage rate of the polyester film becomes maximum and a direction parallel to a light transmission axis of the polarizing plate is 40 degrees or less.
4. The polyester film for protecting a polarizing plate according to claim 1, wherein an absolute value of an angle between a direction in which a heat shrinkage rate of the polyester film becomes maximum and a direction parallel to a light transmission axis of the polarizing plate is 35 degrees or less.
5. The polyester film for protecting a polarizing plate according to claim 1, wherein an absolute value of an angle between a direction in which a heat shrinkage rate of the polyester film becomes maximum and a direction parallel to a light transmission axis of the polarizing plate is 33 degrees or less.
6. The polyester film for protecting a polarizing plate according to claim 1, wherein an absolute value of an angle between a direction in which a heat shrinkage rate of the polyester film becomes maximum and a direction parallel to a light transmission axis of the polarizing plate is 15 degrees or less.
7. The polyester film for protecting a polarizing plate according to claim 2, wherein an absolute value of an angle between a direction in which a heat shrinkage rate of the polyester film becomes maximum and a TD direction is 40 degrees or less.
8. The polyester film for protecting a polarizing plate according to claim 2, wherein an absolute value of an angle between a direction in which a heat shrinkage rate of the polyester film becomes maximum and a TD direction is 35 degrees or less.
9. The polyester film for protecting a polarizing plate according to claim 2, wherein an absolute value of an angle between a direction in which a heat shrinkage rate of the polyester film becomes maximum and a TD direction is 33 degrees or less.
10. The polyester film for protecting a polarizing plate according to claim 2, wherein an absolute value of an angle between a direction in which a heat shrinkage rate of the polyester film becomes maximum and a TD direction is 15 degrees or less.
11. The polyester film for protecting a polarizing plate according to claim 1, wherein the ratio F f/Fv is 3.2 or more.
12. The polyester film for protecting a polarizing plate according to claim 1, wherein the ratio F f/Fv is 11.1 or less.
13. The polyester film for protecting a polarizing plate according to claim 2, wherein the ratio F TD/FMD is 3.2 or more.
14. The polyester film for protecting a polarizing plate according to claim 2, wherein the ratio F TD/FMD is 11.1 or less.
15. The polyester film for protecting a polarizing plate according to claim 1, wherein the shrinkage force F f of the polyester film is 1000N/m or more.
16. The polyester film for protecting a polarizing plate according to claim 2, wherein the shrinkage force F TD of the polyester film is 1000N/m or more.
17. The polyester film for protecting a polarizing plate according to claim 1, wherein the polyester film has a shrinkage force F f of 4800N/m or less.
18. The polyester film for protecting a polarizing plate according to claim 2, wherein the polyester film has a shrinkage force F TD of 4800N/m or less.
19. The polyester film for protecting a polarizing plate according to claim 1, wherein the shrinkage force F f of the polyester film is 2064N/m or less.
20. The polyester film for protecting a polarizing plate according to claim 2, wherein the shrinkage force F TD of the polyester film is 2064N/m or less.
21. The polyester film for protecting a polarizing plate according to claim 1 or 2, wherein the retardation of the polyester film is 3000nm or more and 30000nm or less.
22. The polyester film for protecting a polarizing plate according to claim 1 or 2, wherein the polyester film is stretched in the TD direction.
23. The polyester film for protecting a polarizing plate according to claim 1 or 2, wherein the polyester film is stretched in the TD direction and then stretched again in the same direction in a cooling step after heat fixing.
24. The polyester film for protecting a polarizing plate according to claim 2, wherein the polyester film is stretched in the same direction in a cooling step after stretching in the TD direction and heat fixing, and a direction parallel to the light transmission axis of the polarizing plate is parallel to the TD direction of the polyester film.
25. The polyester film for protecting a polarizing plate according to claim 1 or 2, wherein the thickness of the polyester film is 40 to 200 μm.
26. The polyester film for protecting a polarizing plate according to claim 1 or 2, wherein the thickness of the polyester film is 40 to 100 μm.
27. The polyester film for protecting a polarizing plate according to claim 1, wherein the polyester film has a hard coat layer, an antireflection layer, a low reflection layer, an antiglare layer, or an antireflection antiglare layer on a surface opposite to a surface on which the polarizing plate is laminated.
28. A polarizing plate comprising a polarizing plate and the polyester film for protecting a polarizing plate according to claim 2 laminated on at least one surface of the polarizing plate.
29. A polarizing plate comprising a polarizing plate and the polyester film for protecting a polarizing plate according to claim 1 or 2 laminated on one surface of the polarizing plate, wherein the polarizing plate has no film on the other surface of the polarizing plate.
30. A polarizing plate comprising a polarizing plate and the polyester film for protecting a polarizing plate according to claim 1 or 2 laminated on one surface of the polarizing plate, wherein the polarizing plate has no film but a coating layer on the other surface of the polarizing plate.
31. The polarizing plate of claim 28, wherein a direction parallel to a transmission axis of the polarizing plate is parallel to a TD direction of the polyester film.
32. The polarizing plate according to any one of claims 28 to 31, wherein the polarizing plate has a rectangular shape, and the long side of the polarizing plate is parallel to the light transmission axis thereof.
33. A liquid crystal display device includes: a backlight light source; and a liquid crystal cell disposed between the 2 polarizing plates,
At least one of the 2 polarizing plates is the polarizing plate according to any one of claims 28 to 31.
34. A liquid crystal display device includes: a backlight light source; and a liquid crystal cell disposed between the 2 polarizing plates,
One of the 2 polarizing plates is the polarizing plate of claim 32.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211005534.4A CN115308821B (en) | 2017-09-15 | 2018-09-12 | Polyester film for protecting polarizer |
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2017177630 | 2017-09-15 | ||
| JP2017-177630 | 2017-09-15 | ||
| CN202211005534.4A CN115308821B (en) | 2017-09-15 | 2018-09-12 | Polyester film for protecting polarizer |
| CN201880057327.9A CN111051937B (en) | 2017-09-15 | 2018-09-12 | Polarizer protective film, polarizing plate and liquid crystal display device |
| PCT/JP2018/033793 WO2019054406A1 (en) | 2017-09-15 | 2018-09-12 | Polarizer protective film, polarizing plate, and liquid crystal display device |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201880057327.9A Division CN111051937B (en) | 2017-09-15 | 2018-09-12 | Polarizer protective film, polarizing plate and liquid crystal display device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115308821A CN115308821A (en) | 2022-11-08 |
| CN115308821B true CN115308821B (en) | 2024-05-24 |
Family
ID=65722819
Family Applications (3)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201880057327.9A Active CN111051937B (en) | 2017-09-15 | 2018-09-12 | Polarizer protective film, polarizing plate and liquid crystal display device |
| CN202010291212.5A Active CN111443416B (en) | 2017-09-15 | 2018-09-12 | Polarizing plate and liquid crystal display device |
| CN202211005534.4A Active CN115308821B (en) | 2017-09-15 | 2018-09-12 | Polyester film for protecting polarizer |
Family Applications Before (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201880057327.9A Active CN111051937B (en) | 2017-09-15 | 2018-09-12 | Polarizer protective film, polarizing plate and liquid crystal display device |
| CN202010291212.5A Active CN111443416B (en) | 2017-09-15 | 2018-09-12 | Polarizing plate and liquid crystal display device |
Country Status (5)
| Country | Link |
|---|---|
| JP (4) | JP6708996B2 (en) |
| KR (2) | KR102453214B1 (en) |
| CN (3) | CN111051937B (en) |
| TW (2) | TWI744551B (en) |
| WO (1) | WO2019054406A1 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR102621169B1 (en) * | 2019-01-11 | 2024-01-05 | 산진 옵토일렉트로닉스 (난징) 컴퍼니 리미티드 | Preparation Method of Polarizing Plate |
| KR102662107B1 (en) | 2019-01-11 | 2024-05-02 | 산진 옵토일렉트로닉스 (난징) 컴퍼니 리미티드 | Preparation Method of Polarizing Plate |
| KR20200087435A (en) | 2019-01-11 | 2020-07-21 | 주식회사 엘지화학 | Polarizing Plate |
| WO2021200367A1 (en) * | 2020-03-31 | 2021-10-07 | 東洋紡株式会社 | Polyester film for protecting polarizer, polarizer, and liquid crystal display device |
| WO2022009725A1 (en) | 2020-07-07 | 2022-01-13 | 東洋紡株式会社 | Liquid crystal display device |
| CN112164324B (en) * | 2020-09-04 | 2022-07-15 | 中国科学技术大学 | Organic light emitting display device with changing polarization state of emergent light |
| KR20230095970A (en) * | 2020-10-23 | 2023-06-29 | 도요보 가부시키가이샤 | Polyethylene terephthalate-based resin film, polarizing plate using the same, transparent conductive film, touch panel and image display device |
| WO2023248877A1 (en) * | 2022-06-22 | 2023-12-28 | 東洋紡株式会社 | Polyester film for protecting polarizer, polarizing plate, and liquid crystal display device |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001098089A (en) * | 1999-09-29 | 2001-04-10 | Fuji Photo Film Co Ltd | Polyester carrier and silver halide photographic sensitive material |
| JP2004099754A (en) * | 2002-09-10 | 2004-04-02 | Teijin Ltd | Optical film |
| JP2004226799A (en) * | 2003-01-24 | 2004-08-12 | Konica Minolta Holdings Inc | Polarizing plate protective film, polarizing plate, and material for image display |
| CN101208189A (en) * | 2005-06-10 | 2008-06-25 | 富士胶片株式会社 | Cellulose acylate film, process for producing the same, polarizing plate, retardation film, optical compensating film, antireflection film, and liquid-crystal display |
| CN101849207A (en) * | 2007-12-07 | 2010-09-29 | 日东电工株式会社 | Liquid crystal panel and liquid crystal display device |
| JP2013200435A (en) * | 2012-03-26 | 2013-10-03 | Mitsubishi Plastics Inc | Polyester film for polarizing plate-protection |
| CN105143967A (en) * | 2013-04-19 | 2015-12-09 | 东洋纺株式会社 | Liquid-crystal display, polarizing plate, and polarizer-protecting film |
| JP2016141058A (en) * | 2015-02-03 | 2016-08-08 | 東レ株式会社 | Biaxially oriented polyester film and method for producing the same |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008107499A (en) | 2006-10-24 | 2008-05-08 | Fujifilm Corp | Polarizing plate and liquid crystal display device |
| JP2009198666A (en) | 2008-02-20 | 2009-09-03 | Fujifilm Corp | Method of manufacturing polarizing plate, polarizing plate, and liquid crystal display using the polarizing plate |
| US8512833B2 (en) * | 2008-05-16 | 2013-08-20 | Skc Co., Ltd | Heat-shrinkable polyester film |
| JP2011028251A (en) * | 2009-06-26 | 2011-02-10 | Fujifilm Corp | Phase difference film, polarizing plate, and liquid crystal display device |
| JP2013109116A (en) * | 2011-11-21 | 2013-06-06 | Konica Minolta Advanced Layers Inc | Method for manufacturing polarizing film protection film, polarizing film protection film, polarizing plate and liquid crystal display device using the same |
| JP2013181063A (en) * | 2012-02-29 | 2013-09-12 | Nitto Denko Corp | Self-rolling adhesive film |
| US10539717B2 (en) * | 2012-12-20 | 2020-01-21 | Samsung Sdi Co., Ltd. | Polarizing plates and optical display apparatuses including the polarizing plates |
| JP5990128B2 (en) * | 2013-05-01 | 2016-09-07 | 富士フイルム株式会社 | Liquid crystal display |
| WO2015137446A1 (en) * | 2014-03-13 | 2015-09-17 | 富士フイルム株式会社 | Liquid crystal display device |
| JP6378540B2 (en) * | 2014-05-26 | 2018-08-22 | 富士フイルム株式会社 | Polyester film, method for producing polyester film, polarizing plate, image display device and liquid crystal display device |
| JPWO2015190190A1 (en) * | 2014-06-11 | 2017-04-20 | コニカミノルタ株式会社 | Liquid crystal display |
| US11137522B2 (en) * | 2014-09-30 | 2021-10-05 | Nitto Denko Corporation | One-side-protected polarizing film, pressure-sensitive-adhesive-layer-attached polarizing film, image display device, and method for continuously producing same |
| JP6205089B1 (en) | 2016-03-31 | 2017-09-27 | 東洋紡株式会社 | Liquid crystal display |
-
2018
- 2018-09-12 WO PCT/JP2018/033793 patent/WO2019054406A1/en active Application Filing
- 2018-09-12 JP JP2019542260A patent/JP6708996B2/en active Active
- 2018-09-12 CN CN201880057327.9A patent/CN111051937B/en active Active
- 2018-09-12 CN CN202010291212.5A patent/CN111443416B/en active Active
- 2018-09-12 KR KR1020207010201A patent/KR102453214B1/en active IP Right Grant
- 2018-09-12 KR KR1020207011074A patent/KR102468284B1/en active IP Right Grant
- 2018-09-12 CN CN202211005534.4A patent/CN115308821B/en active Active
- 2018-09-14 TW TW107132377A patent/TWI744551B/en active
- 2018-09-14 TW TW109113144A patent/TWI805917B/en active
-
2020
- 2020-02-10 JP JP2020020389A patent/JP7322736B2/en active Active
- 2020-04-13 JP JP2020071555A patent/JP7288878B2/en active Active
-
2023
- 2023-07-20 JP JP2023118266A patent/JP2023143934A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001098089A (en) * | 1999-09-29 | 2001-04-10 | Fuji Photo Film Co Ltd | Polyester carrier and silver halide photographic sensitive material |
| JP2004099754A (en) * | 2002-09-10 | 2004-04-02 | Teijin Ltd | Optical film |
| JP2004226799A (en) * | 2003-01-24 | 2004-08-12 | Konica Minolta Holdings Inc | Polarizing plate protective film, polarizing plate, and material for image display |
| CN101208189A (en) * | 2005-06-10 | 2008-06-25 | 富士胶片株式会社 | Cellulose acylate film, process for producing the same, polarizing plate, retardation film, optical compensating film, antireflection film, and liquid-crystal display |
| CN101849207A (en) * | 2007-12-07 | 2010-09-29 | 日东电工株式会社 | Liquid crystal panel and liquid crystal display device |
| JP2013200435A (en) * | 2012-03-26 | 2013-10-03 | Mitsubishi Plastics Inc | Polyester film for polarizing plate-protection |
| CN105143967A (en) * | 2013-04-19 | 2015-12-09 | 东洋纺株式会社 | Liquid-crystal display, polarizing plate, and polarizer-protecting film |
| JP2016141058A (en) * | 2015-02-03 | 2016-08-08 | 東レ株式会社 | Biaxially oriented polyester film and method for producing the same |
Also Published As
| Publication number | Publication date |
|---|---|
| TWI744551B (en) | 2021-11-01 |
| JP2020144376A (en) | 2020-09-10 |
| TWI805917B (en) | 2023-06-21 |
| CN115308821A (en) | 2022-11-08 |
| KR20200046111A (en) | 2020-05-06 |
| TW201920394A (en) | 2019-06-01 |
| JPWO2019054406A1 (en) | 2020-04-02 |
| CN111443416B (en) | 2022-06-17 |
| CN111443416A (en) | 2020-07-24 |
| JP2020091494A (en) | 2020-06-11 |
| JP2023143934A (en) | 2023-10-06 |
| KR102468284B1 (en) | 2022-11-17 |
| JP7322736B2 (en) | 2023-08-08 |
| CN111051937B (en) | 2022-08-26 |
| CN111051937A (en) | 2020-04-21 |
| KR102453214B1 (en) | 2022-10-11 |
| JP6708996B2 (en) | 2020-06-10 |
| TW202030241A (en) | 2020-08-16 |
| JP7288878B2 (en) | 2023-06-08 |
| KR20200054241A (en) | 2020-05-19 |
| WO2019054406A1 (en) | 2019-03-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN115308821B (en) | Polyester film for protecting polarizer | |
| CN111443417B (en) | Liquid crystal display device having a light shielding layer | |
| JP6303544B2 (en) | Liquid crystal display device and polarizing plate | |
| JP2022048363A (en) | Polyester film for polarizer protection, polarizing plate, and liquid crystal display device | |
| WO2023248877A1 (en) | Polyester film for protecting polarizer, polarizing plate, and liquid crystal display device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |