JP4101540B2 - Ethylene-modified polyvinyl alcohol film - Google Patents
Ethylene-modified polyvinyl alcohol film Download PDFInfo
- Publication number
- JP4101540B2 JP4101540B2 JP2002078889A JP2002078889A JP4101540B2 JP 4101540 B2 JP4101540 B2 JP 4101540B2 JP 2002078889 A JP2002078889 A JP 2002078889A JP 2002078889 A JP2002078889 A JP 2002078889A JP 4101540 B2 JP4101540 B2 JP 4101540B2
- Authority
- JP
- Japan
- Prior art keywords
- film
- ethylene
- modified pva
- polarizing
- degree
- 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.)
- Expired - Lifetime
Links
- 229920002451 polyvinyl alcohol Polymers 0.000 title claims description 38
- 239000004372 Polyvinyl alcohol Substances 0.000 title claims description 35
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 68
- 238000005520 cutting process Methods 0.000 claims description 39
- 238000006116 polymerization reaction Methods 0.000 claims description 18
- 239000005977 Ethylene Substances 0.000 claims description 16
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims description 15
- 238000007127 saponification reaction Methods 0.000 claims description 15
- NLKNQRATVPKPDG-UHFFFAOYSA-M potassium iodide Chemical compound [K+].[I-] NLKNQRATVPKPDG-UHFFFAOYSA-M 0.000 description 36
- 239000007864 aqueous solution Substances 0.000 description 28
- 230000010287 polarization Effects 0.000 description 27
- 238000010438 heat treatment Methods 0.000 description 26
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 24
- 239000004973 liquid crystal related substance Substances 0.000 description 24
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 21
- 239000004327 boric acid Substances 0.000 description 21
- 238000001035 drying Methods 0.000 description 19
- 238000002834 transmittance Methods 0.000 description 17
- 238000000034 method Methods 0.000 description 14
- 238000004043 dyeing Methods 0.000 description 12
- 235000011187 glycerol Nutrition 0.000 description 12
- 238000011282 treatment Methods 0.000 description 12
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 description 12
- 241000694440 Colpidium aqueous Species 0.000 description 11
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 11
- ILJSQTXMGCGYMG-UHFFFAOYSA-N triacetic acid Chemical compound CC(=O)CC(=O)CC(O)=O ILJSQTXMGCGYMG-UHFFFAOYSA-N 0.000 description 9
- -1 vinyl halides Chemical class 0.000 description 9
- 150000003839 salts Chemical class 0.000 description 8
- 239000000243 solution Substances 0.000 description 8
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 7
- 229910052751 metal Inorganic materials 0.000 description 7
- 239000002184 metal Substances 0.000 description 7
- 230000008961 swelling Effects 0.000 description 7
- 238000012360 testing method Methods 0.000 description 7
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical compound [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 description 6
- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 6
- 239000000975 dye Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 229910052740 iodine Inorganic materials 0.000 description 6
- 239000011630 iodine Substances 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- 239000000178 monomer Substances 0.000 description 6
- 239000004094 surface-active agent Substances 0.000 description 6
- 229920001567 vinyl ester resin Polymers 0.000 description 6
- 239000011592 zinc chloride Substances 0.000 description 6
- 235000005074 zinc chloride Nutrition 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- RTZKZFJDLAIYFH-UHFFFAOYSA-N ether Substances CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 5
- 230000001681 protective effect Effects 0.000 description 5
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 description 4
- 239000000853 adhesive Substances 0.000 description 4
- 230000001070 adhesive effect Effects 0.000 description 4
- 238000005187 foaming Methods 0.000 description 4
- 239000002904 solvent Substances 0.000 description 4
- 229920002554 vinyl polymer Polymers 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- IMROMDMJAWUWLK-UHFFFAOYSA-N Ethenol Chemical group OC=C IMROMDMJAWUWLK-UHFFFAOYSA-N 0.000 description 3
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 239000003945 anionic surfactant Substances 0.000 description 3
- 150000002148 esters Chemical group 0.000 description 3
- 238000001125 extrusion Methods 0.000 description 3
- 239000012467 final product Substances 0.000 description 3
- 125000001449 isopropyl group Chemical group [H]C([H])([H])C([H])(*)C([H])([H])[H] 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 239000002736 nonionic surfactant Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 229920005989 resin Polymers 0.000 description 3
- 239000011347 resin Substances 0.000 description 3
- 150000005846 sugar alcohols Polymers 0.000 description 3
- 230000000007 visual effect Effects 0.000 description 3
- BYEAHWXPCBROCE-UHFFFAOYSA-N 1,1,1,3,3,3-hexafluoropropan-2-ol Chemical compound FC(F)(F)C(O)C(F)(F)F BYEAHWXPCBROCE-UHFFFAOYSA-N 0.000 description 2
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-Butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 description 2
- UZKWTJUDCOPSNM-UHFFFAOYSA-N 1-ethenoxybutane Chemical compound CCCCOC=C UZKWTJUDCOPSNM-UHFFFAOYSA-N 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 2
- SOGAXMICEFXMKE-UHFFFAOYSA-N Butylmethacrylate Chemical compound CCCCOC(=O)C(C)=C SOGAXMICEFXMKE-UHFFFAOYSA-N 0.000 description 2
- 229920002284 Cellulose triacetate Polymers 0.000 description 2
- VQTUBCCKSQIDNK-UHFFFAOYSA-N Isobutene Chemical compound CC(C)=C VQTUBCCKSQIDNK-UHFFFAOYSA-N 0.000 description 2
- BAPJBEWLBFYGME-UHFFFAOYSA-N Methyl acrylate Chemical compound COC(=O)C=C BAPJBEWLBFYGME-UHFFFAOYSA-N 0.000 description 2
- WHNWPMSKXPGLAX-UHFFFAOYSA-N N-Vinyl-2-pyrrolidone Chemical compound C=CN1CCCC1=O WHNWPMSKXPGLAX-UHFFFAOYSA-N 0.000 description 2
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 2
- UWHCKJMYHZGTIT-UHFFFAOYSA-N Tetraethylene glycol, Natural products OCCOCCOCCOCCO UWHCKJMYHZGTIT-UHFFFAOYSA-N 0.000 description 2
- ZJCCRDAZUWHFQH-UHFFFAOYSA-N Trimethylolpropane Chemical compound CCC(CO)(CO)CO ZJCCRDAZUWHFQH-UHFFFAOYSA-N 0.000 description 2
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 2
- 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 2
- 150000001639 boron compounds Chemical class 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 229920001727 cellulose butyrate Polymers 0.000 description 2
- 238000007872 degassing Methods 0.000 description 2
- 229940105990 diglycerin Drugs 0.000 description 2
- GPLRAVKSCUXZTP-UHFFFAOYSA-N diglycerol Chemical compound OCC(O)COCC(O)CO GPLRAVKSCUXZTP-UHFFFAOYSA-N 0.000 description 2
- FJKIXWOMBXYWOQ-UHFFFAOYSA-N ethenoxyethane Chemical compound CCOC=C FJKIXWOMBXYWOQ-UHFFFAOYSA-N 0.000 description 2
- 239000000155 melt Substances 0.000 description 2
- FQPSGWSUVKBHSU-UHFFFAOYSA-N methacrylamide Chemical compound CC(=C)C(N)=O FQPSGWSUVKBHSU-UHFFFAOYSA-N 0.000 description 2
- RQAKESSLMFZVMC-UHFFFAOYSA-N n-ethenylacetamide Chemical compound CC(=O)NC=C RQAKESSLMFZVMC-UHFFFAOYSA-N 0.000 description 2
- ZQXSMRAEXCEDJD-UHFFFAOYSA-N n-ethenylformamide Chemical compound C=CNC=O ZQXSMRAEXCEDJD-UHFFFAOYSA-N 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 239000004014 plasticizer Substances 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- POSICDHOUBKJKP-UHFFFAOYSA-N prop-2-enoxybenzene Chemical compound C=CCOC1=CC=CC=C1 POSICDHOUBKJKP-UHFFFAOYSA-N 0.000 description 2
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 2
- KAKVFSYQVNHFBS-UHFFFAOYSA-N (5-hydroxycyclopenten-1-yl)-phenylmethanone Chemical compound OC1CCC=C1C(=O)C1=CC=CC=C1 KAKVFSYQVNHFBS-UHFFFAOYSA-N 0.000 description 1
- FFJCNSLCJOQHKM-CLFAGFIQSA-N (z)-1-[(z)-octadec-9-enoxy]octadec-9-ene Chemical compound CCCCCCCC\C=C/CCCCCCCCOCCCCCCCC\C=C/CCCCCCCC FFJCNSLCJOQHKM-CLFAGFIQSA-N 0.000 description 1
- LPMBTLLQQJBUOO-KTKRTIGZSA-N (z)-n,n-bis(2-hydroxyethyl)octadec-9-enamide Chemical compound CCCCCCCC\C=C/CCCCCCCC(=O)N(CCO)CCO LPMBTLLQQJBUOO-KTKRTIGZSA-N 0.000 description 1
- BQCIDUSAKPWEOX-UHFFFAOYSA-N 1,1-Difluoroethene Chemical compound FC(F)=C BQCIDUSAKPWEOX-UHFFFAOYSA-N 0.000 description 1
- LAYAKLSFVAPMEL-UHFFFAOYSA-N 1-ethenoxydodecane Chemical compound CCCCCCCCCCCCOC=C LAYAKLSFVAPMEL-UHFFFAOYSA-N 0.000 description 1
- QJJDJWUCRAPCOL-UHFFFAOYSA-N 1-ethenoxyoctadecane Chemical compound CCCCCCCCCCCCCCCCCCOC=C QJJDJWUCRAPCOL-UHFFFAOYSA-N 0.000 description 1
- OVGRCEFMXPHEBL-UHFFFAOYSA-N 1-ethenoxypropane Chemical compound CCCOC=C OVGRCEFMXPHEBL-UHFFFAOYSA-N 0.000 description 1
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 1
- JAHNSTQSQJOJLO-UHFFFAOYSA-N 2-(3-fluorophenyl)-1h-imidazole Chemical compound FC1=CC=CC(C=2NC=CN=2)=C1 JAHNSTQSQJOJLO-UHFFFAOYSA-N 0.000 description 1
- OEPOKWHJYJXUGD-UHFFFAOYSA-N 2-(3-phenylmethoxyphenyl)-1,3-thiazole-4-carbaldehyde Chemical compound O=CC1=CSC(C=2C=C(OCC=3C=CC=CC=3)C=CC=2)=N1 OEPOKWHJYJXUGD-UHFFFAOYSA-N 0.000 description 1
- GOXQRTZXKQZDDN-UHFFFAOYSA-N 2-Ethylhexyl acrylate Chemical compound CCCCC(CC)COC(=O)C=C GOXQRTZXKQZDDN-UHFFFAOYSA-N 0.000 description 1
- PGYJSURPYAAOMM-UHFFFAOYSA-N 2-ethenoxy-2-methylpropane Chemical compound CC(C)(C)OC=C PGYJSURPYAAOMM-UHFFFAOYSA-N 0.000 description 1
- RUMACXVDVNRZJZ-UHFFFAOYSA-N 2-methylpropyl 2-methylprop-2-enoate Chemical compound CC(C)COC(=O)C(C)=C RUMACXVDVNRZJZ-UHFFFAOYSA-N 0.000 description 1
- CFVWNXQPGQOHRJ-UHFFFAOYSA-N 2-methylpropyl prop-2-enoate Chemical compound CC(C)COC(=O)C=C CFVWNXQPGQOHRJ-UHFFFAOYSA-N 0.000 description 1
- 125000003903 2-propenyl group Chemical group [H]C([*])([H])C([H])=C([H])[H] 0.000 description 1
- RWHRFHQRVDUPIK-UHFFFAOYSA-N 50867-57-7 Chemical class CC(=C)C(O)=O.CC(=C)C(O)=O RWHRFHQRVDUPIK-UHFFFAOYSA-N 0.000 description 1
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 description 1
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 1
- OSDWBNJEKMUWAV-UHFFFAOYSA-N Allyl chloride Chemical compound ClCC=C OSDWBNJEKMUWAV-UHFFFAOYSA-N 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 description 1
- FERIUCNNQQJTOY-UHFFFAOYSA-M Butyrate Chemical compound CCCC([O-])=O FERIUCNNQQJTOY-UHFFFAOYSA-M 0.000 description 1
- FERIUCNNQQJTOY-UHFFFAOYSA-N Butyric acid Natural products CCCC(O)=O FERIUCNNQQJTOY-UHFFFAOYSA-N 0.000 description 1
- RPNUMPOLZDHAAY-UHFFFAOYSA-N Diethylenetriamine Chemical compound NCCNCCN RPNUMPOLZDHAAY-UHFFFAOYSA-N 0.000 description 1
- JIGUQPWFLRLWPJ-UHFFFAOYSA-N Ethyl acrylate Chemical compound CCOC(=O)C=C JIGUQPWFLRLWPJ-UHFFFAOYSA-N 0.000 description 1
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 1
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 description 1
- DKNPRRRKHAEUMW-UHFFFAOYSA-N Iodine aqueous Chemical compound [K+].I[I-]I DKNPRRRKHAEUMW-UHFFFAOYSA-N 0.000 description 1
- HETCEOQFVDFGSY-UHFFFAOYSA-N Isopropenyl acetate Chemical compound CC(=C)OC(C)=O HETCEOQFVDFGSY-UHFFFAOYSA-N 0.000 description 1
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 description 1
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 description 1
- GYCMBHHDWRMZGG-UHFFFAOYSA-N Methylacrylonitrile Chemical compound CC(=C)C#N GYCMBHHDWRMZGG-UHFFFAOYSA-N 0.000 description 1
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 description 1
- CNCOEDDPFOAUMB-UHFFFAOYSA-N N-Methylolacrylamide Chemical compound OCNC(=O)C=C CNCOEDDPFOAUMB-UHFFFAOYSA-N 0.000 description 1
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 1
- 229920006197 POE laurate Polymers 0.000 description 1
- OFOBLEOULBTSOW-UHFFFAOYSA-N Propanedioic acid Natural products OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 1
- QYKIQEUNHZKYBP-UHFFFAOYSA-N Vinyl ether Chemical class C=COC=C QYKIQEUNHZKYBP-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 125000005396 acrylic acid ester group Chemical group 0.000 description 1
- 239000003522 acrylic cement Substances 0.000 description 1
- 150000001336 alkenes Chemical class 0.000 description 1
- 150000003973 alkyl amines Chemical class 0.000 description 1
- 125000005907 alkyl ester group Chemical group 0.000 description 1
- 150000005215 alkyl ethers Chemical class 0.000 description 1
- 125000000129 anionic group Chemical group 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000009529 body temperature measurement Methods 0.000 description 1
- CQEYYJKEWSMYFG-UHFFFAOYSA-N butyl acrylate Chemical compound CCCCOC(=O)C=C CQEYYJKEWSMYFG-UHFFFAOYSA-N 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 150000001732 carboxylic acid derivatives Chemical class 0.000 description 1
- 229920002301 cellulose acetate Polymers 0.000 description 1
- BPHHNXJPFPEJOF-UHFFFAOYSA-J chembl296966 Chemical compound [Na+].[Na+].[Na+].[Na+].[O-]S(=O)(=O)C1=CC(S([O-])(=O)=O)=C(N)C2=C(O)C(N=NC3=CC=C(C=C3OC)C=3C=C(C(=CC=3)N=NC=3C(=C4C(N)=C(C=C(C4=CC=3)S([O-])(=O)=O)S([O-])(=O)=O)O)OC)=CC=C21 BPHHNXJPFPEJOF-UHFFFAOYSA-J 0.000 description 1
- 238000004040 coloring Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000007334 copolymerization reaction Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- DSARWKALPGYFTA-UHFFFAOYSA-L disodium 4-hydroxy-7-[(5-hydroxy-6-phenyldiazenyl-7-sulfonatonaphthalen-2-yl)carbamoylamino]-3-phenyldiazenylnaphthalene-2-sulfonate Chemical compound [Na+].[Na+].[O-]S(=O)(=O)C1=CC2=CC(NC(=O)NC=3C=C4C=C(C(N=NC=5C=CC=CC=5)=C(O)C4=CC=3)S([O-])(=O)=O)=CC=C2C(O)=C1N=NC1=CC=CC=C1 DSARWKALPGYFTA-UHFFFAOYSA-L 0.000 description 1
- DDLNJHAAABRHFY-UHFFFAOYSA-L disodium 8-amino-7-[[4-[4-[(4-oxidophenyl)diazenyl]phenyl]phenyl]diazenyl]-2-phenyldiazenyl-3,6-disulfonaphthalen-1-olate Chemical compound [Na+].[Na+].NC1=C(C(=CC2=CC(=C(C(=C12)O)N=NC1=CC=CC=C1)S(=O)(=O)[O-])S(=O)(=O)[O-])N=NC1=CC=C(C=C1)C1=CC=C(C=C1)N=NC1=CC=C(C=C1)O DDLNJHAAABRHFY-UHFFFAOYSA-L 0.000 description 1
- NJDNXYGOVLYJHP-UHFFFAOYSA-L disodium;2-(3-oxido-6-oxoxanthen-9-yl)benzoate Chemical compound [Na+].[Na+].[O-]C(=O)C1=CC=CC=C1C1=C2C=CC(=O)C=C2OC2=CC([O-])=CC=C21 NJDNXYGOVLYJHP-UHFFFAOYSA-L 0.000 description 1
- VTEBSADXXKSKOE-UHFFFAOYSA-L disodium;4-[[2,4-diamino-5-[[3-[[2,4-diamino-5-[(4-sulfonatophenyl)diazenyl]phenyl]diazenyl]phenyl]diazenyl]phenyl]diazenyl]benzenesulfonate Chemical compound [Na+].[Na+].NC1=CC(N)=C(N=NC=2C=C(C=CC=2)N=NC=2C(=CC(N)=C(N=NC=3C=CC(=CC=3)S([O-])(=O)=O)C=2)N)C=C1N=NC1=CC=C(S([O-])(=O)=O)C=C1 VTEBSADXXKSKOE-UHFFFAOYSA-L 0.000 description 1
- GMSCBRSQMRDRCD-UHFFFAOYSA-N dodecyl 2-methylprop-2-enoate Chemical compound CCCCCCCCCCCCOC(=O)C(C)=C GMSCBRSQMRDRCD-UHFFFAOYSA-N 0.000 description 1
- YRIUSKIDOIARQF-UHFFFAOYSA-N dodecyl benzenesulfonate Chemical compound CCCCCCCCCCCCOS(=O)(=O)C1=CC=CC=C1 YRIUSKIDOIARQF-UHFFFAOYSA-N 0.000 description 1
- 229940071161 dodecylbenzenesulfonate Drugs 0.000 description 1
- UYMKPFRHYYNDTL-UHFFFAOYSA-N ethenamine Chemical class NC=C UYMKPFRHYYNDTL-UHFFFAOYSA-N 0.000 description 1
- YCUBDDIKWLELPD-UHFFFAOYSA-N ethenyl 2,2-dimethylpropanoate Chemical compound CC(C)(C)C(=O)OC=C YCUBDDIKWLELPD-UHFFFAOYSA-N 0.000 description 1
- GLVVKKSPKXTQRB-UHFFFAOYSA-N ethenyl dodecanoate Chemical compound CCCCCCCCCCCC(=O)OC=C GLVVKKSPKXTQRB-UHFFFAOYSA-N 0.000 description 1
- GFJVXXWOPWLRNU-UHFFFAOYSA-N ethenyl formate Chemical compound C=COC=O GFJVXXWOPWLRNU-UHFFFAOYSA-N 0.000 description 1
- AFSIMBWBBOJPJG-UHFFFAOYSA-N ethenyl octadecanoate Chemical compound CCCCCCCCCCCCCCCCCC(=O)OC=C AFSIMBWBBOJPJG-UHFFFAOYSA-N 0.000 description 1
- UIWXSTHGICQLQT-UHFFFAOYSA-N ethenyl propanoate Chemical compound CCC(=O)OC=C UIWXSTHGICQLQT-UHFFFAOYSA-N 0.000 description 1
- NKSJNEHGWDZZQF-UHFFFAOYSA-N ethenyl(trimethoxy)silane Chemical compound CO[Si](OC)(OC)C=C NKSJNEHGWDZZQF-UHFFFAOYSA-N 0.000 description 1
- SUPCQIBBMFXVTL-UHFFFAOYSA-N ethyl 2-methylprop-2-enoate Chemical compound CCOC(=O)C(C)=C SUPCQIBBMFXVTL-UHFFFAOYSA-N 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- XUCNUKMRBVNAPB-UHFFFAOYSA-N fluoroethene Chemical compound FC=C XUCNUKMRBVNAPB-UHFFFAOYSA-N 0.000 description 1
- 108010025899 gelatin film Proteins 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 1
- 150000002497 iodine compounds Chemical class 0.000 description 1
- 125000000959 isobutyl group Chemical group [H]C([H])([H])C([H])(C([H])([H])[H])C([H])([H])* 0.000 description 1
- PBOSTUDLECTMNL-UHFFFAOYSA-N lauryl acrylate Chemical compound CCCCCCCCCCCCOC(=O)C=C PBOSTUDLECTMNL-UHFFFAOYSA-N 0.000 description 1
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- VRVDFJOCCWSFLI-UHFFFAOYSA-K trisodium 3-[[4-[(6-anilino-1-hydroxy-3-sulfonatonaphthalen-2-yl)diazenyl]-5-methoxy-2-methylphenyl]diazenyl]naphthalene-1,5-disulfonate Chemical compound [Na+].[Na+].[Na+].COc1cc(N=Nc2cc(c3cccc(c3c2)S([O-])(=O)=O)S([O-])(=O)=O)c(C)cc1N=Nc1c(O)c2ccc(Nc3ccccc3)cc2cc1S([O-])(=O)=O VRVDFJOCCWSFLI-UHFFFAOYSA-K 0.000 description 1
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Landscapes
- Manufacture Of Macromolecular Shaped Articles (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、偏光フィルムの製造原料として有用な、偏光性能が高く、耐久性能が良好で、かつ色斑の少ないエチレン変性ポリビニルアルコールフィルムに関する。
【０００２】
【従来の技術】
光の透過および遮蔽機能を有する偏光板は、光のスイッチング機能を有する液晶とともに、液晶ディスプレイ（ＬＣＤ）の基本的な構成要素である。このＬＣＤの適用分野も、開発初期の頃の電卓および腕時計などの小型機器から、近年では、ラップトップパソコン、ワープロ、液晶カラープロジェクター、車載用ナビゲーションシステム、液晶テレビ、パーソナルホンおよび屋内外の計測機器などの広範囲に広がり、従来品以上に偏光性能や耐久性能が高く、色斑が少ない大面積の偏光板が求められている。
【０００３】
偏光板は、一般にポリビニルアルコール系重合体フィルム（以下、ポリビニルアルコール系重合体を「ＰＶＡ」、ポリビニルアルコール系重合体フィルムを「ＰＶＡフィルム」と略記することがある）を一軸延伸させて染色するか、または染色して一軸延伸した後、ホウ素化合物で固定処理を行うことにより（染色と固定処理が同時の場合もある）得られた偏光フィルムに、三酢酸セルロース（ＴＡＣ）フィルムや酢酸・酪酸セルロース（ＣＡＢ）フィルムなどの保護膜を貼り合わせた構成となっている。
【０００４】
【発明が解決しようとする課題】
近年液晶ディスプレイの用途が高精細のパソコンモニターや家庭用テレビジョンなどに広がり、従来よりもコントラストや耐久性の要求が高まっており、より高い偏光性能や、耐久性能が求められるようになっている。
【０００５】
さらに、外観的には均一に見えるＰＶＡフィルムであっても、これにより得られる偏光フィルムには外部から判別困難な色斑が内在していることがある。この色斑は保護膜などを積層した最終製品（偏光板）でないと確認しにくい。この最終製品において色斑が発現すると、良品である保護膜などの副資材も不良品として廃棄されることになるので、製造上の大きな損失となる。従来色斑を減少させる方法として、特開平６−１３８３１９号公報などに記載されているように、ポリビニルアルコールフィルムの厚み斑や複屈折斑を減少させるという観点から検討がなされてきた。ポリビニルアルコールフィルムの厚み斑や複屈折斑を減少させることにより、色斑はある程度減少して当時の要求レベルを満足することは可能となったが、近年の性能が向上した最終製品（偏光板および液晶ディスプレイ装置）で問題となるようなレベルの色斑を減少させることは困難であることが分かってきた。
【０００６】
また、液晶ディスプレイ装置の大型化に伴い大面積の偏光フィルムが要求されるようになってきた。従来の液晶ディスプレイ装置は表示面積が比較的小さく偏光板単独で用いられていたため色斑は問題になりにくかったが、表示面積が大面積の場合には、表示面積全体の均一性が要求されることや、視野角補正フィルムなど他のフィルムと組み合わせて用いられることが多くなってきたことなどの理由により、色斑の問題が顕在化してきた。前記したように、これまではフィルムの各種構造や物性を調整することにより色斑の低減を図ってきたが、この方法だけでは十分ではなく、フィルムの各種構造や物性の調整に加えて、ポリマー構造を特定の範囲に制御することが必要であるとの結論に達した。
【０００７】
そこで、本発明の目的は、偏光性能や耐久性能が良好で、色斑が少なく、液晶ディスプレイの大型化に対応可能な偏光フィルムの製造原料として有用なポリビニルアルコールフィルムを提供することにある。
【０００８】
【課題を解決するための手段】
本発明者らは上記課題を解決するために鋭意検討した結果、エチレン単位の含有量１〜４モル％、重合度２０００〜４０００、けん化度９９．０〜９９．９９モル％のエチレン変性ポリビニルアルコールから製膜され、熱水切断温度が６６〜７３℃であるエチレン変性ポリビニルアルコールフィルムを見出し、本発明を完成した。このエチレン変性ポリビニルアルコールフィルムは、偏光性能および耐久性能に優れているうえに、色斑が少なく、液晶ディスプレイの大型化に対応可能な偏光フィルムの製造原料として有用である。
また、本発明のエチレン変性ポリビニルアルコールフィルムは、フィルムのＴＤ方向に５ｃｍ離れた二点間の熱水切断温度の差が１℃以下であることが、色斑を低減させるうえでさらに好ましく、さらにフィルムのＴＤ方向に１ｃｍ離れた二点間の熱水切断温度の差が０．５℃以下であることが、色斑を低減させるうえでさらに一層好ましく、さらにまたフィルムの厚みが１０〜５０μｍであることが色斑を低減させるうえで特に好ましい。
【０００９】
【発明の実施の形態】
本発明において用いられるエチレン変性ポリビニルアルコール（エチレン変性ＰＶＡ）としては、エチレンとビニルエステル系モノマーとを共重合して得られたエチレン−ビニルエステル系重合体をけん化し、ビニルエステル単位をビニルアルコール単位としたものを用いることができる。このビニルエステル系モノマーとしては、例えば、ギ酸ビニル、酢酸ビニル、プロピオン酸ビニル、バレリン酸ビニル、ラウリン酸ビニル、ステアリン酸ビニル、安息香酸ビニル、ピバリン酸ビニル、バーサティック酸ビニル等を挙げることができ、これらのなかでも酢酸ビニルを用いるのが好ましい。
【００１０】
エチレン変性ＰＶＡにおけるエチレン単位の含有量（エチレンの共重合量）は、１〜４モル％であり、好ましくは１．５〜３モル％であり、より好ましくは２〜３モル％である。エチレン単位の含有量が１モル％未満の場合には、得られる偏光フィルムにおける偏光性能および耐久性能の向上効果や色斑の低減効果が小さくなり、好ましくない。一方、エチレン単位の含有量が４モル％を超えると、エチレン変性ＰＶＡの水との親和性が低くなり、フィルム膜面の均一性が低下して、偏光フィルムの色斑の原因となりやすいため不適である。
【００１１】
さらに、エチレンとビニルエステル系モノマーを共重合させる際には、必要に応じて、共重合可能なモノマーを発明の効果を損なわない範囲内（好ましくは１５モル％以下、より好ましくは５モル％以下の割合）で共重合させることもできる。
【００１２】
このようなビニルエステル系モノマーと共重合可能なモノマーとしては、例えば、プロピレン、１−ブテン、イソブテン等の炭素数３〜３０のオレフィン類；アクリル酸およびその塩；アクリル酸メチル、アクリル酸エチル、アクリル酸ｎ−プロピル、アクリル酸ｉ−プロピル、アクリル酸ｎ−ブチル、アクリル酸ｉ−ブチル、アクリル酸ｔ−ブチル、アクリル酸２−エチルへキシル、アクリル酸ドデシル、アクリル酸オクタデシル等のアクリル酸エステル類；メタクリル酸およびその塩；メタクリル酸メチル、メタクリル酸エチル、メタクリル酸ｎ−プロピル、メタクリル酸ｉ−プロピル、メタクリル酸ｎ−ブチル、メタクリル酸ｉ−ブチル、メタクリル酸ｔ−ブチル、メタクリル酸２−エチルへキシル、メタクリル酸ドデシル、メタクリル酸オクタデシル等のメタクリル酸エステル類；アクリルアミド、Ｎ−メチルアクリルアミド、Ｎ−エチルアクリルアミド、Ｎ，Ｎ−ジメチルアクリルアミド、ジアセトンアクリルアミド、アクリルアミドプロパンスルホン酸およびその塩、アクリルアミドプロピルジメチルアミンおよびその塩、Ｎ−メチロールアクリルアミドおよびその誘導体等のアクリルアミド誘導体；メタクリルアミド、Ｎ−メチルメタクリルアミド、Ｎ−エチルメタクリルアミド、メタクリルアミドプロパンスルホン酸およびその塩、メタクリルアミドプロピルジメチルアミンおよびその塩、Ｎ−メチロールメタクリルアミドおよびその誘導体等のメタクリルアミド誘導体；Ｎ−ビニルホルムアミド、Ｎ−ビニルアセトアミド、Ｎ−ビニルピロリドン等のＮ−ビニルアミド類；メチルビニルエーテル、エチルビニルエーテル、ｎ−プロピルビニルエーテル、ｉ−プロピルビニルエーテル、ｎ−ブチルビニルエーテル、ｉ−ブチルビニルエーテル、ｔ−ブチルビニルエーテル、ドデシルビニルエーテル、ステアリルビニルエーテル等のビニルエーテル類；アクリロニトリル、メタクリロニトリル等のニトリル類；塩化ビニル、塩化ビニリデン、フッ化ビニル、フッ化ビニリデン等のハロゲン化ビニル類；酢酸アリル、塩化アリル等のアリル化合物；マレイン酸およびその塩またはそのエステル；イタコン酸およびその塩またはそのエステル；ビニルトリメトキシシラン等のビニルシリル化合物；酢酸イソプロペニル、Ｎ−ビニルホルムアミド、Ｎ−ビニルアセトアミド、Ｎ−ビニルピロリドン等のＮ−ビニルアミド類を挙げることができる。
【００１３】
前記エチレン変性ＰＶＡフィルムを構成するエチレン変性ＰＶＡの重合度は、偏光フィルムのＰＶＡの重合度は偏光性能と耐久性の点から２０００〜４０００であり、２２００〜３５００が好ましく、２５００〜３０００が特に好ましい。エチレン変性ＰＶＡの重合度が２０００より小さい場合には、偏光フィルムの偏光性能や耐久性能が低下し、好ましくない。また、重合度が４０００より大きいと、重合時の生産性が低くなり工業的に好ましくないうえに、水との親和性が低くなる場合があり、フィルム膜面の均一性が低下して、偏光フィルムの色斑の原因となりやすいため好ましくない。
【００１４】
前記エチレン変性ＰＶＡの重合度は、ＧＰＣ測定から求めた重量平均重合度である。この重量平均重合度は、単分散ＰＭＭＡを標品として移動相に２０ミリモル／リットルのトリフルオロ酢酸ソーダを加えたヘキサフルオロイソプロパノール（ＨＦＩＰ）を用い、４０℃でＧＰＣ測定を行って求めた値である。
【００１５】
エチレン変性ＰＶＡフィルムを構成するエチレン変性ＰＶＡのけん化度は、偏光フィルムの偏光性能および耐久性の点から９９．０〜９９．９９モル％であり、９９．９〜９９．９９モル％がより好ましく、９９．９５〜９９．９９モル％が特に好ましい。けん化度が９９．０モル％より低い場合には、偏光フィルムの耐久性が低下し、好ましくない。また、けん化度が９９．９９モル％を超えると、エチレン変性ＰＶＡの製造時に樹脂の着色等の問題があり、製造に著しい困難を伴う。
前記けん化度とは、けん化によりビニルアルコール単位に変換され得る単位の中で、実際にビニルアルコール単位にけん化されている単位の割合を示したものである。なお、エチレン変性ＰＶＡのけん化度は、ＪＩＳ記載の方法により測定を行った。
【００１６】
エチレン変性ＰＶＡを使用してエチレン変性ＰＶＡフィルムを製造する方法として、水を含むエチレン変性ＰＶＡを使用した溶融押出方式による製膜法の他に、例えばエチレン変性ＰＶＡを溶剤に溶解したエチレン変性ＰＶＡ溶液を使用して、流延製膜法、湿式製膜法（貧溶媒中への吐出）、ゲル製膜法（エチレン変性ＰＶＡ水溶液を一旦冷却ゲル化した後、溶媒を抽出除去し、エチレン変性ＰＶＡフィルムを得る方法）、およびこれらの組み合わせによる方法などを採用することができる。これらのなかでも流延製膜法および溶融押出製膜法が、良好なエチレン変性ＰＶＡフィルムを得る観点から好ましい。得られたエチレン変性ＰＶＡフィルムは、必要に応じて乾燥および熱処理が施される。
【００１７】
エチレン変性ＰＶＡフィルムを製造する際に使用されるエチレン変性ＰＶＡを溶解する溶剤としては、例えば、ジメチルスルホキシド、ジメチルホルムアミド、ジメチルアセトアミド、Ｎ−メチルピロリドン、エチレングリコール、グリセリン、プロピレングリコール、ジエチレングリコール、トリエチレングリコール、テトラエチレングリコール、トリメチロールプロパン、エチレンジアミン、ジエチレントリアミン、グリセリン、水などを挙げることができ、これらのうち１種または２種以上を使用することができる。これらのなかでも、ジメチルスルホキシド、水、またはグリセリンと水の混合溶媒が好適に使用される。
【００１８】
エチレン変性ＰＶＡフィルムを製造する際に使用されるエチレン変性ＰＶＡ溶液または水を含むエチレン変性ＰＶＡにおけるエチレン変性ＰＶＡの割合はエチレン変性ＰＶＡの重合度に応じて変化するが、２０〜７０重量％が好適であり、２５〜６０重量％がより好適であり、３０〜５５重量％がさらに好適であり、３５〜５０重量％が最も好適である。エチレン変性ＰＶＡの割合が７０重量％を超えるとエチレン変性ＰＶＡ溶液または水を含むエチレン変性ＰＶＡの粘度が高くなり過ぎて、フィルムの原液を調製する際に濾過や脱泡が困難となり、異物や欠点のないフィルムを得ることが困難となる。また、エチレン変性ＰＶＡの割合が２０重量％より低いとエチレン変性ＰＶＡ溶液または水を含むエチレン変性ＰＶＡの粘度が低くなり過ぎて、目的とする厚みを有するＰＶＡフィルムを製造することが困難になる。また、このエチレン変性ＰＶＡ溶液または水を含むエチレン変性ＰＶＡには、必要に応じて可塑剤、界面活性剤、二色性染料などを含有させてもよい。
【００１９】
エチレン変性ＰＶＡフィルムを製造する際に可塑剤として、多価アルコールを添加することが好ましい。多価アルコールとしては、例えば、エチレングリコール、グリセリン、プロピレングリコール、ジエチレングリコール、ジグリセリン、トリエチレングリコール、テトラエチレングリコール、トリメチロールプロパンなどを挙げることができ、これらのうち１種または２種以上を使用することができる。これらの中でも延伸性向上効果からジグリセリンやエチレングリコールやグリセリンが好適に使用される。
【００２０】
多価アルコールの添加量としてはエチレン変性ＰＶＡ１００重量部に対し１〜３０重量部が好ましく、３〜２５重量部がさらに好ましく、５〜２０重量部が最も好ましい。１重量部より少ないと、染色性や延伸性が低下する場合があり、３０重量部より多いと、エチレン変性ＰＶＡフィルムが柔軟になりすぎて、取り扱い性が低下する場合がある。
【００２１】
エチレン変性ＰＶＡフィルムを製造する際には、界面活性剤を添加することが好ましい。界面活性剤の種類としては特に限定はないが、アニオン性またはノニオン性の界面活性剤が好ましい。アニオン性界面活性剤としては、たとえば、ラウリン酸カリウムなどのカルボン酸型、オクチルサルフェートなどの硫酸エステル型、ドデシルベンゼンスルホネートなどのスルホン酸型のアニオン性界面活性剤が好適である。ノニオン性界面活性剤としては、たとえば、ポリオキシエチレンオレイルエーテルなどのアルキルエーテル型、ポリオキシエチレンオクチルフェニルエーテルなどのアルキルフェニルエーテル型、ポリオキシエチレンラウレートなどのアルキルエステル型、ポリオキシエチレンラウリルアミノエーテルなどのアルキルアミン型、ポリオキシエチレンラウリン酸アミドなどのアルキルアミド型、ポリオキシエチレンポリオキシプロピレンエーテルなどのポリプロピレングリコールエーテル型、オレイン酸ジエタノールアミドなどのアルカノールアミド型、ポリオキシアルキレンアリルフェニルエーテルなどのアリルフェニルエーテル型などのノニオン性界面活性剤が好適である。これらの界面活性剤の１種または２種以上の組み合わせで使用することができる。
【００２２】
界面活性剤の添加量としては、エチレン変性ＰＶＡ１００重量部に対して０．０１〜１重量部が好ましく、０．０２〜０．５重量部がさらに好ましく、０．０５〜０．３重量部が最も好ましい。０．０１重量部より少ないと、製膜性や剥離性向上の効果が現れにくく、１重量部より多いと、界面活性剤がエチレン変性ＰＶＡフィルムの表面に溶出してブロッキングの原因になり、取り扱い性が低下する場合がある。
【００２３】
本発明のエチレン変性ＰＶＡフィルムの熱水切断温度は６６〜７３℃であり、６８〜７３℃が好ましく、７０℃〜７３℃がさらに好ましい。エチレン変性ＰＶＡフィルムの熱水切断温度が６６℃よりも低い場合には、溶解しかけたフィルムを延伸するような状態となり分子配向が起こりにくいため、偏光フィルムの偏光性能が不十分になる。熱水切断温度が７３℃より高いと、フィルムが延伸されにくくなり、偏光フィルムの偏光性能が低くなるため好ましくない。
エチレン変性ＰＶＡフィルムに乾燥および熱処理を施す際に、その処理の温度および時間を変化させることにより、フィルムの熱水切断温度を調整することができる。
【００２４】
本発明のエチレン変性ＰＶＡフィルムは、フィルムのＴＤ方向に５ｃｍ離れた二点間の熱水切断温度の差が１℃以下であることが好ましく、０．８℃以下であることがさらに好ましく、０.５℃以下であることが特に好ましい。熱水切断温度の差が１℃を超えると、エチレン変性ＰＶＡフィルムから偏光フィルムを作成した際に色斑が目視で目立ちやすくなり、液晶ディスプレイ装置に組み込んだ際に色調変化が起こりやすくなるため好ましくない。５ｃｍ離れた二点間の熱水切断温度の差を１℃以下にするには、フィルムのＴＤ方向にかかる熱履歴を均一にする公知の方法を適宜組み合わせて行えば良い。例えば、フィルムのＴＤ方向の樹脂温度、ドラム温度、ロール温度、乾燥温度、熱処理温度などを均一にする方法が挙げられる。本発明においては、フィルムのＴＤ方向の個々の熱履歴が均一でなくとも、最終的に得られたフィルムのＴＤ方向に５ｃｍ離れた二点間の熱水切断温度の差が１℃以下であればよい。
【００２５】
本発明のエチレン変性ＰＶＡフィルムは、さらにフィルムのＴＤ方向に１ｃｍ離れた二点間の熱水切断温度の差が０．５℃以下であることが好ましく、０．４℃以下であることがさらに好ましく、０.３℃以下であることが特に好ましい。熱水切断温度の差が０．５℃を超えると、エチレン変性ＰＶＡフィルムから偏光フィルムを作成した際に色斑が目視で目立ちやすくなり、液晶ディスプレイ装置に組み込んだ際に色調変化が起こりやすくなるため好ましくない。１ｃｍ離れた二点間の熱水切断温度の差を０．５℃以下にするには、フィルムのＴＤ方向にかかる熱履歴を均一にする公知の方法を適宜組み合わせて行えば良い。例えば、フィルムのＴＤ方向の樹脂温度、ドラム温度、ロール温度、乾燥温度、熱処理温度などを均一にする方法が挙げられる。本発明においては、フィルムのＴＤ方向の個々の熱履歴が均一でなくとも、最終的に得られたフィルムのＴＤ方向に１ｃｍ離れた二点間の熱水切断温度の差が０．５℃以下であればよい。
【００２６】
本発明のエチレン変性ＰＶＡフィルムは厚みが１０〜５０μｍであることが好ましく、２０〜４０μｍであることがさらに好ましい。厚みが１０μｍより小さいと、フィルム強度が低すぎて均一な延伸が行いにくく、偏光フィルムの色斑が発生しやすい。厚みが５０μｍを超えると、エチレン変性ＰＶＡフィルムを一軸延伸して偏光フィルムを作成した際に端部のネックインによる厚み変化が発生し易くなり、偏光フィルムの色斑が強調されやすいので好ましくない。
【００２７】
また、本発明のエチレン変性ＰＶＡフィルムから偏光フィルムを製造するには、例えばエチレン変性ＰＶＡフィルムを染色、一軸延伸、固定処理、乾燥処理をし、さらに必要に応じて熱処理を行えばよく、染色、一軸延伸、固定処理の操作の順番に特に制限はない。また、一軸延伸を二回またはそれ以上行っても良い。
【００２８】
染色は、一軸延伸前、一軸延伸時、一軸延伸後のいずれでも可能である。染色に用いる染料としては、ヨウ素−ヨウ化カリウム；ダイレクトブラック １７、１９、１５４；ダイレクトブラウン ４４、１０６、１９５、２１０、２２３；ダイレクトレッド ２、２３、２８、３１、３７、３９、７９、８１、２４０、２４２、２４７；ダイレクトブルー １、１５、２２、７８、９０、９８、１５１、１６８、２０２、２３６、２４９、２７０；ダイレクトバイオレット ９、１２、５１、９８；ダイレクトグリーン １、８５；ダイレクトイエロー ８、１２、４４、８６、８７；ダイレクトオレンジ ２６、３９、１０６、１０７などの二色性染料などが、１種または２種以上の混合物で使用できる。通常染色は、ＰＶＡフィルムを上記染料を含有する溶液中に浸漬させることにより行うことが一般的であるが、ＰＶＡフィルムに混ぜて製膜するなど、その処理条件や処理方法は特に制限されるものではない。
【００２９】
一軸延伸は、湿式延伸法または乾熱延伸法が使用でき、ホウ酸水溶液などの温水中（前記染料を含有する溶液中や後記固定処理浴中でもよい）または吸水後のエチレン変性ＰＶＡフィルムを用いて空気中で行うことができる。延伸温度は、特に限定されないが、エチレン変性ＰＶＡフィルムを温水中で延伸（湿式延伸）する場合は３０〜９０℃が好適であり、また乾熱延伸する場合は５０〜１８０℃が好適である。また一軸延伸の延伸倍率（多段の一軸延伸の場合には合計の延伸倍率）は、偏光フィルムの偏光性能の点から４倍以上が好ましく、特に５倍以上が最も好ましい。延伸倍率の上限は特に制限はないが、８倍以下であると均一な延伸が得られやすいので好ましい。延伸後のフィルムの厚さは、２〜２０μｍが好ましく、５〜１５μｍがより好ましい。
【００３０】
エチレン変性ＰＶＡフィルムへの上記染料の吸着を強固にすることを目的に、固定処理を行うことが多い。固定処理に使用する処理浴には、通常、ホウ酸および／またはホウ素化合物が添加される。また、必要に応じて処理浴中にヨウ素化合物を添加してもよい。
【００３１】
得られた偏光フィルムの乾燥処理は、３０〜１５０℃で行うのが好ましく、５０〜１５０℃で行うのがより好ましい。
【００３２】
以上のようにして得られた偏光フィルムは、通常、その両面または片面に、光学的に透明で、かつ機械的強度を有した保護膜を貼り合わせて偏光板として使用される。保護膜としては、三酢酸セルロース（ＴＡＣ）フィルム、酢酸・酪酸セルロース（ＣＡＢ）フィルム、アクリル系フィルム、ポリエステル系フィルムなどが使用される。また、貼り合わせのための接着剤としては、ＰＶＡ系の接着剤やウレタン系の接着剤などを挙げることができるが、なかでもＰＶＡ系の接着剤が好適である。
【００３３】
以上のようにして得られた偏光板はアクリル系等の粘着剤をコートした後、ガラス基板に貼り合わせて液晶ディスプレイ装置の部品として使用され、あるいは位相差フィルムや視野角向上フィルム、輝度向上フィルム等と貼り合わせて用いられる。
【００３４】
【実施例】
以下、実施例を挙げて本発明を具体的に説明するが、本発明はこれらにより何ら限定されるものではない。なお、実施例中の熱水切断温度、ならびに偏光フィルムの透過率、偏光度および２色性比は以下の方法により評価した。
【００３５】
熱水切断温度の測定
エチレン変性ＰＶＡフィルムを長さ５ｃｍ、幅方向に幅５ｍｍの大きさに切断した。フィルムの下部に幅方向の断面積１ｍｍ２当たり１ｇの重りを取り付けて水中に吊るした。水を１分間当たり３℃の速さで加熱し、フィルムが溶解して切断する温度を測定した。
偏光フィルムの透過率、偏光度および２色性比の測定：
偏光フィルムを島津製作所製の分光光度計ＵＶ−２２００（積分球付属）を用い、日本電子機械工業会規格（ＥＩＡＪ）ＬＤ−２０１−１９８３に準拠して、Ｃ光源、２度視野にて測定・計算して透過率（Ｔ）と偏光度（Ｖ）を求めた。さらに必要に応じて下式から２色性比（Ｒｄ）を求めた。
Ｒｄ＝ｌｏｇ（Ｔ−Ｔ×Ｖ）／ｌｏｇ（Ｔ＋Ｔ×Ｖ）
【００３６】
実施例１
エチレン単位の含有量２．５モル％、けん化度９９．９５モル％、重合度２４００のエチレン変性ＰＶＡ１００重量部に、グリセリン１０重量部および水１７０重量部を含浸させたものを溶融混練し、脱泡後、Ｔダイから金属ロールに溶融押出し、製膜した。乾燥および熱処理後に得られたエチレン変性ＰＶＡフィルムは厚みが４０μｍであり、フィルムの熱水切断温度の平均値は７０℃であった。
【００３７】
このようにして得られたエチレン変性ＰＶＡフィルムを予備膨潤、染色、一軸延伸、固定処理、乾燥、熱処理の順番で連続的に処理して偏光フィルムを作成した。すなわち、前記エチレン変性ＰＶＡフィルムを３０℃の水中に６０秒間浸して予備膨潤し、ホウ酸濃度４０ｇ／リットル、ヨウ素濃度０．４ｇ／リットル、ヨウ化カリウム濃度６０ｇ／リットルの３５℃の水溶液中に２分間浸した。続いて、ホウ酸濃度４％の５５℃の水溶液中で６倍に一軸延伸を行い、ヨウ化カリウム濃度６０ｇ／リットル、ホウ酸濃度４０ｇ／リットル、塩化亜鉛濃度１０ｇ／リットルの３０℃の水溶液中に５分間浸漬して固定処理を行った。この後、エチレン変性ＰＶＡフィルムを取り出し、定長下、４０℃で熱風乾燥し、さらに１００℃で５分間熱処理を行った。
【００３８】
得られた偏光フィルムの透過率は４４．３４％、偏光度は９９．４６％であり、計算により求めた二色性比は４９．１３であった。得られた偏光フィルムを延伸軸方向（０度）に対して平行状態に配置した２枚の偏光板の間に１０度の角度で置いたところ、偏光フィルムの幅方向に対して中央部と端部の輝度の差が小さく、色斑も小さく良好であった。これを一軸延伸した方向を固定して、６０℃、９０％ＲＨの環境で耐湿熱性試験を行った。２４時間後の偏光フィルムの透過率は４６．５０％、偏光度は９１．２４％であり、計算により求めた二色性比は２７．２７であった。
【００３９】
得られた偏光フィルムに、４％のポリビニルアルコール水溶液を用い、トリアセテートフィルムを貼り合わせて偏光板を得た。得られた偏光板を延伸軸方向（０度）に対して平行状態に配置した２枚の偏光板の間に１０度の角度で置いたところ、偏光板の幅方向に対して中央部と端部の輝度の差が小さく、色斑も小さく良好であった。
【００４０】
実施例２
エチレン単位の含有量２．１モル％、けん化度９９．９２モル％、重合度３０００のエチレン変性ＰＶＡ１００重量部に、グリセリン１０重量部および水２００重量部を含浸させたものを溶融混練し、脱泡後、Ｔダイから金属ロールに溶融押出し、製膜した。乾燥および熱処理後に得られたエチレン変性ＰＶＡフィルムの厚みは３５μｍであり、フィルムの熱水切断温度の平均値は６８℃であった。
【００４１】
このようにして得られたエチレン変性ＰＶＡフィルムを予備膨潤、染色、一軸延伸、固定処理、乾燥、熱処理の順番で連続的に処理して偏光フィルムを作成した。すなわち、前記エチレン変性ＰＶＡフィルムを３０℃の水中に６０秒間浸して予備膨潤し、ホウ酸濃度４０ｇ／リットル、ヨウ素濃度０．４ｇ／リットル、ヨウ化カリウム濃度６０ｇ／リットルの３５℃の水溶液中に２分間浸した。続いて、ホウ酸濃度４％の５５℃の水溶液中で６倍に一軸延伸を行い、ヨウ化カリウム濃度６０ｇ／リットル、ホウ酸濃度４０ｇ／リットル、塩化亜鉛濃度１０ｇ／リットルの３０℃の水溶液中に５分間浸漬して固定処理を行った。この後、エチレン変性ＰＶＡフィルムを取り出し、定長下、４０℃で熱風乾燥し、さらに１００℃で５分間熱処理を行った。
【００４２】
得られた偏光フィルムの透過率は４３．６３％、偏光度は９９．８５％であり、計算により求めた二色性比は５３．５１であった。得られた偏光フィルムを延伸軸方向（０度）に対して平行状態に配置した２枚の偏光板の間に１０度の角度で置いたところ、偏光フィルムの幅方向に対して中央部と端部の輝度の差が小さく、色斑も小さく良好であった。これを一軸延伸した方向を固定して、６０℃、９０％ＲＨの環境で耐湿熱性試験を行った。２４時間後の偏光フィルムの透過率は４５．２１％、偏光度は９６．８２％であり、計算により求めた二色性比は３６．３４であった。
【００４３】
得られた偏光フィルムに、４％のポリビニルアルコール水溶液を用いて、トリアセテートフィルムを貼り合わせて偏光板を得た。得られた偏光板を延伸軸方向（０度）に対して平行状態に配置した２枚の偏光板の間に１０度の角度で置いたところ、偏光板の幅方向に対して中央部と端部の輝度の差が小さく、色斑も小さく良好であった。
【００４４】
比較例１
けん化度９９．９５モル％、重合度２４００のＰＶＡ１００重量部に、グリセリン１０重量部および水１７０重量部を含浸させたものを溶融混練し、脱泡後、Ｔダイから金属ロールに溶融押出し、製膜した。乾燥および熱処理後に得られたＰＶＡフィルムの厚みは４０μｍであり、フィルムの熱水切断温度の平均値は７０℃であった。
【００４５】
前記ＰＶＡフィルムを予備膨潤、染色、一軸延伸、固定処理、乾燥、熱処理の順番で連続的に処理して偏光フィルムを作成した。すなわち、前記ＰＶＡフィルムを３０℃の水中に６０秒間浸して予備膨潤し、ホウ酸濃度４０ｇ／リットル、ヨウ素濃度０．４ｇ／リットル、ヨウ化カリウム濃度４０ｇ／リットルの３５℃の水溶液中に２分間浸した。続いて、ホウ酸濃度４％の５５℃の水溶液中で５．８倍に一軸延伸を行い、ヨウ化カリウム濃度４０ｇ／リットル、ホウ酸濃度４０ｇ／リットル、塩化亜鉛濃度１０ｇ／リットルの３０℃の水溶液中に５分間浸漬して固定処理を行った。この後、ＰＶＡフィルムを取り出し、定長下、４０℃で熱風乾燥し、さらに１００℃で５分間熱処理を行った。
【００４６】
得られた偏光フィルムの透過率は４３．５２％、偏光度は９９．７６％であり、計算により求めた二色性比は４９．０３であった。得られた偏光フィルムを延伸軸方向（０度）に対して平行状態に配置した２枚の偏光板の間に１０度の角度で置いたところ、偏光フィルムの幅方向に対して中央部と端部の輝度の差が大きく、また色斑も大きく大型液晶ディスプレイ用の偏光フィルムとして不良であった。これを一軸延伸した方向を固定して、６０℃、９０％ＲＨの環境で耐湿熱性試験を行った。２４時間後の偏光フィルムの透過率は４７．９９％、偏光度は８５．５１％であり、計算により求めた二色性比は２２．９３であった。
【００４７】
得られた偏光フィルムに、４％のポリビニルアルコール水溶液を用いて、トリアセテートフィルムを貼り合わせ、偏光板を得た。得られた偏光板を延伸軸方向（０度）に対して平行状態に配置した２枚の偏光板の間に１０度の角度で置いたところ、偏光板の幅方向に対して中央部と端部の輝度の差が大きく、色斑も大きく大型液晶ディスプレイ用の偏光膜として不良であった。
【００４８】
比較例２
エチレン単位の含有量２．５モル％、けん化度９９．９５モル％、重合度２４００のエチレン変性ＰＶＡ１００重量部に、グリセリン１０重量部および水１７０重量部を含浸させたものを溶融混練し、脱泡後、Ｔダイから金属ロールに溶融押出し、製膜した。乾燥および熱処理後に得られたエチレン変性ＰＶＡフィルムの厚みは４０μｍであり、フィルムの熱水切断温度の平均値は７５℃であった。
【００４９】
このようにして得られたエチレン変性ＰＶＡフィルムを予備膨潤、染色、一軸延伸、固定処理、乾燥、熱処理の順番で連続的に処理して偏光フィルムを作成した。すなわち、前記エチレン変性ＰＶＡフィルムを３０℃の水中に６０秒間浸して予備膨潤し、ホウ酸濃度４０ｇ／リットル、ヨウ素濃度０．４ｇ／リットル、ヨウ化カリウム濃度６０ｇ／リットルの３５℃の水溶液中に２分間浸した。続いて、ホウ酸濃度４％の６０℃の水溶液中で５．８倍に一軸延伸を行い、ヨウ化カリウム濃度６０ｇ／リットル、ホウ酸濃度４０ｇ／リットル、塩化亜鉛濃度１０ｇ／リットルの３０℃の水溶液中に５分間浸漬して固定処理を行った。この後、エチレン変性ＰＶＡフィルムを取り出し、定長下、４０℃で熱風乾燥し、さらに１００℃で５分間熱処理を行った。
【００５０】
得られた偏光フィルムの透過率は５２．３６％、偏光度は７３．０４％であり、計算により求めた二色性比は１９．８２であった。得られた偏光フィルムを延伸軸方向（０度）に対して平行状態に配置した２枚の偏光板の間に１０度の角度で置いたところ、偏光フィルムの幅方向に対して中央部と端部の輝度の差が大きく、また色斑も大きく大型液晶ディスプレイ用の偏光フィルムとして不良であった。これを一軸延伸した方向を固定して、６０℃、９０％ＲＨの環境で耐湿熱性試験を行った。２４時間後の偏光フィルムの透過率は８５．４９％、偏光度は１２．６２％であり、計算により求めた二色性比は７．６９であった。
【００５１】
得られた偏光フィルムを４％のポリビニルアルコール水溶液を用いて、トリアセテートフィルムを貼り合わせ、偏光板を得た。得られた偏光板を延伸軸方向（０度）に対して平行状態に配置した２枚の偏光板の間に１０度の角度で置いたところ、偏光板の幅方向に対して中央部と端部の輝度の差が大きく、色斑も大きく大型液晶ディスプレイ用の偏光膜として不良であった。
【００５２】
比較例３
エチレン単位の含有量２．５モル％、けん化度９９．９５モル％、重合度２４００のエチレン変性ＰＶＡ１００重量部に、グリセリン１０重量部および水１７０重量部を含浸させたものを溶融混練し、脱泡後、Ｔダイから金属ロールに溶融押出し、製膜した。乾燥および熱処理後に得られたエチレン変性ＰＶＡフィルムの厚みは４０μｍであり、フィルムの熱水切断温度の平均値は６５℃であった。
【００５３】
このようにして得られたエチレン変性ＰＶＡフィルムを予備膨潤、染色、一軸延伸、固定処理、乾燥、熱処理の順番で連続的に処理して偏光フィルムを作成した。すなわち、前記エチレン変性ＰＶＡフィルムを３０℃の水中に６０秒間浸して予備膨潤し、ホウ酸濃度４０ｇ／リットル、ヨウ素濃度０．４ｇ／リットル、ヨウ化カリウム濃度６０ｇ／リットルの３５℃の水溶液中に２分間浸した。続いて、ホウ酸濃度４％の６０℃の水溶液中で５．８倍に一軸延伸を行い、ヨウ化カリウム濃度５０ｇ／リットル、ホウ酸濃度４０ｇ／リットル、塩化亜鉛濃度１０ｇ／リットルの３０℃の水溶液中に５分間浸漬して固定処理を行った。この後、エチレン変性ＰＶＡフィルムを取り出し、定長下、４０℃で熱風乾燥し、さらに１００℃で５分間熱処理を行った。
【００５４】
得られた偏光フィルムの透過率は４４．３４％、偏光度は９８．４２％であり、計算により求めた二色性比は３８．７８であった。得られた偏光フィルムを延伸軸方向（０度）に対して平行状態に配置した２枚の偏光板の間に１０度の角度で置いたところ、偏光フィルムの幅方向に対して中央部と端部の輝度の差が大きく、また色斑も大きく大型液晶ディスプレイ用の偏光膜として不良であった。これを一軸延伸した方向を固定して、６０℃、９０％ＲＨの環境で耐湿熱性試験を行った。２４時間後の偏光フィルムの透過率は５３．０３％、偏光度は３５．１２％であり、計算により求めた二色性比は３．２０であった。
【００５５】
得られた偏光フィルムに、４％のポリビニルアルコール水溶液を用いて、トリアセテートフィルムを貼り合わせ、偏光板を得た。得られた偏光板を延伸軸方向（０度）に対して平行状態に配置した２枚の偏光板の間に１０度の角度で置いたところ、偏光板の幅方向に対して中央部と端部の輝度の差が大きく、色斑も大きく大型液晶ディスプレイ用の偏光膜として不良であった。
【００５６】
比較例４
エチレン含有量２．５モル％、けん化度９９．９５モル％、重合度１７００のエチレン変性ＰＶＡ１００重量部に、グリセリン１０重量部および水１７０重量部を含浸させたものを溶融混練し、脱泡後、Ｔダイから金属ロールに溶融押出し、製膜した。乾燥および熱処理後に得られたエチレン変性ＰＶＡフィルムの厚みは４０μｍであり、フィルムの熱水切断温度の平均値は７０℃であった。
【００５７】
このようにして得られたエチレン変性前記ＰＶＡフィルムを予備膨潤、染色、一軸延伸、固定処理、乾燥、熱処理の順番で連続的に処理して偏光フィルムを作成した。すなわち、前記エチレン変性ＰＶＡフィルムを３０℃の水中に６０秒間浸して予備膨潤し、ホウ酸濃度４０ｇ／リットル、ヨウ素濃度０．４ｇ／リットル、ヨウ化カリウム濃度６０ｇ／リットルの３５℃の水溶液中に２分間浸した。続いて、ホウ酸濃度４％の６０℃の水溶液中で５．８倍に一軸延伸を行い、ヨウ化カリウム濃度６０ｇ／リットル、ホウ酸濃度４０ｇ／リットル、塩化亜鉛濃度１０ｇ／リットルの３０℃の水溶液中に５分間浸漬して固定処理を行った。この後、エチレン変性ＰＶＡフィルムを取り出し、定長下、４０℃で熱風乾燥し、さらに１００℃で５分間熱処理を行った。
【００５８】
得られた偏光フィルムの透過率は４３．６１％、偏光度は９９．７５％であり、計算により求めた二色性比は４９．４３であった。得られた偏光フィルムを延伸軸方向（０度）に対して平行状態に配置した２枚の偏光板の間に１０度の角度で置いたところ、偏光フィルムの幅方向に対して中央部と端部の輝度の差が大きく、また色斑も大きく大型液晶ディスプレイ用の偏光膜として不良であった。これを一軸延伸した方向を固定して、６０℃、９０％ＲＨの環境で耐湿熱性試験を行った。２４時間後の偏光フィルムの透過率は５５．９８％、偏光度は３０．０５％であり、計算により求めた二色性比は２．９５であった。
【００５９】
得られた偏光フィルムに、４％のポリビニルアルコール水溶液を用いて、トリアセテートフィルムを貼り合わせ、偏光板を得た。得られた偏光板を延伸軸方向（０度）に対して平行状態に配置した２枚の偏光板の間に１０度の角度で置いたところ、偏光板の幅方向に対して中央部と端部の輝度の差が大きく、色斑も大きく大型液晶ディスプレイ用の偏光膜として不良であった。
【００６０】
比較例５
エチレン含有量２．５モル％、けん化度９８．５モル％、重合度２４００のエチレン変性ＰＶＡ１００重量部に、グリセリン１０重量部および水１７０重量部を含浸させたものを溶融混練し、脱泡後、Ｔダイから金属ロールに溶融押出し、製膜した。乾燥および熱処理後に得られたエチレン変性ＰＶＡフィルムの厚みは４０μｍであり、フィルムの熱水切断温度の平均値は７０℃であった。
【００６１】
このようにして得られたエチレン変性ＰＶＡフィルムを予備膨潤、染色、一軸延伸、固定処理、乾燥、熱処理の順番で連続的に処理して偏光フィルムを作成した。すなわち、エチレン変性ＰＶＡフィルムを３０℃の水中に６０秒間浸して予備膨潤し、ホウ酸濃度４０ｇ／リットル、ヨウ素濃度０．４ｇ／リットル、ヨウ化カリウム濃度６０ｇ／リットルの３５℃の水溶液中に２分間浸した。続いて、ホウ酸濃度４％の６０℃の水溶液中で５．９倍に一軸延伸を行い、ヨウ化カリウム濃度５０ｇ／リットル、ホウ酸濃度４０ｇ／リットル、塩化亜鉛濃度１０ｇ／リットルの３０℃の水溶液中に５分間浸漬して固定処理を行った。この後、エチレン変性ＰＶＡフィルムを取り出し、定長下、４０℃で熱風乾燥し、さらに１００℃で５分間熱処理を行った。
【００６２】
得られた偏光フィルムの透過率は４４．２３％、偏光度は９９．４８％であり、計算により求めた二色性比は４８．５１であった。得られた偏光フィルムを延伸軸方向（０度）に対して平行状態に配置した２枚の偏光板の間に１０度の角度で置いたところ、偏光フィルムの幅方向に対して中央部と端部の輝度の差が大きく、また色斑も大きく大型液晶ディスプレイ用の偏光膜として不良であった。これを一軸延伸した方向を固定して、６０℃９０％ＲＨの環境で耐湿熱性試験を行った。２４時間後の偏光フィルムの透過率は５５．０１％、偏光度は３７．５１％であり、計算により求めた二色性比は３．８３であった。
【００６３】
得られた偏光フィルムを４％のポリビニルアルコール水溶液を用いて、トリアセテートフィルムを貼り合わせ、偏光板を得た。得られた偏光板を延伸軸方向（０度）に対して平行状態に配置した２枚の偏光板の間に１０度の角度で置いたところ、偏光板の幅方向に対して中央部と端部の輝度の差が大きく、色斑も大きく大型液晶ディスプレイ用の偏光膜として不良であった。
【００６４】
実施例３
実施例１において、幅方向の熱履歴を変えた以外は実施例１と同様にしてエチレン変性ＰＶＡフィルムを作成した。得られたフィルムの熱水切断温度の平均値は７０℃であり、また、該フィルムの幅方向の熱水切断温度を幅１ｃｍ毎に測定したところ、フィルムのＴＤ方向に５ｃｍ離れた二点間の熱水切断温度の差は最も大きい場所で０．４℃であり、フィルムのＴＤ方向に１ｃｍ離れた二点間の熱水切断温度の差は最も大きい場所で０．２℃であった。このフィルムを用い、実施例１と同様にして偏光フィルムを作成したところ、目視観察による色斑は非常に小さく、非常に良好であった。
【００６５】
実施例４
実施例１において、幅方向の熱履歴を変えた以外は実施例１と同様にしてエチレン変性ＰＶＡフィルムを作成した。得られたフィルムの熱水切断温度の平均値は７０℃であり、また、該フィルムの幅方向の熱水切断温度を幅１ｃｍ毎に測定したところ、フィルムのＴＤ方向に５ｃｍ離れた二点間の熱水切断温度の差は最も大きい場所で０．６℃であり、フィルムのＴＤ方向に１ｃｍ離れた二点間の熱水切断温度の差は最も大きい場所で０．３℃であった。このフィルムを用い、実施例１と同様にして偏光フィルムを作成したところ、目視観察による色斑は小さく、良好であった。
【００６６】
実施例５
実施例１において、幅方向の熱履歴を変えた以外は実施例１と同様にしてエチレン変性ＰＶＡフィルムを作成した。得られたフィルムの熱水切断温度の平均値は７０℃であり、また、該フィルムの幅方向の熱水切断温度を幅１ｃｍ毎に測定したところ、フィルムのＴＤ方向に５ｃｍ離れた二点間の熱水切断温度の差は最も大きい場所で０．９℃であり、フィルムのＴＤ方向に１ｃｍ離れた二点間の熱水切断温度の差は最も大きい場所で０．５℃であった。このフィルムを用い、実施例１と同様にして偏光フィルムを作成したところ、目視観察による色斑は小さく、使用可能なレベルであった。
【００６７】
【発明の効果】
本発明によれば、偏光フィルムにしたときに偏光性能が良好で、色斑を低減することが可能なエチレン変性ＰＶＡフィルムが得られる。そして、このエチレン変性ＰＶＡフィルムを用いて、色斑が少なく大型の液晶ディスプレイ用として好適な偏光フィルムを得ることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ethylene-modified polyvinyl alcohol film that is useful as a raw material for producing a polarizing film, has high polarization performance, good durability performance, and few color spots.
[0002]
[Prior art]
A polarizing plate having a light transmission and shielding function is a basic component of a liquid crystal display (LCD) together with a liquid crystal having a light switching function. This LCD can be applied to small devices such as calculators and wristwatches in the early days of development, and in recent years, laptop computers, word processors, liquid crystal color projectors, in-vehicle navigation systems, liquid crystal televisions, personal phones, and indoor and outdoor measuring devices. There is a need for a polarizing plate with a large area that spreads over a wide area, has higher polarization performance and durability than conventional products, and has less color spots.
[0003]
The polarizing plate is generally dyed by uniaxially stretching a polyvinyl alcohol polymer film (hereinafter, the polyvinyl alcohol polymer may be abbreviated as “PVA” and the polyvinyl alcohol polymer film as “PVA film”). Or, after dyeing and uniaxially stretching, and fixing with a boron compound (the dyeing and fixing may be simultaneous), a cellulose triacetate (TAC) film or cellulose acetate / butyrate (CAB) A protective film such as a film is laminated.
[0004]
[Problems to be solved by the invention]
In recent years, the use of liquid crystal displays has expanded to high-definition personal computer monitors and home televisions, and demands for contrast and durability have increased, and higher polarization performance and durability performance have been demanded. .
[0005]
Furthermore, even if it is a PVA film that looks uniform in appearance, the resulting polarizing film may have color spots that are difficult to distinguish from the outside. This color spot is difficult to confirm unless it is a final product (polarizing plate) in which a protective film or the like is laminated. When color spots appear in the final product, a secondary material such as a protective film, which is a good product, is discarded as a defective product, resulting in a large manufacturing loss. As a conventional method for reducing color spots, studies have been made from the viewpoint of reducing thickness spots and birefringence spots on a polyvinyl alcohol film, as described in JP-A-6-138319. By reducing the thickness spots and birefringence spots on the polyvinyl alcohol film, it became possible to reduce the color spots to some extent to meet the level required at the time, but the final product (polarizing plate and It has been found difficult to reduce the level of color spots that can cause problems in liquid crystal display devices.
[0006]
In addition, a large-area polarizing film has been demanded with an increase in size of a liquid crystal display device. The conventional liquid crystal display device has a relatively small display area and is used alone with a polarizing plate, so that color spots are not a problem. However, when the display area is large, the entire display area is required to be uniform. In addition, the problem of color spots has become apparent due to the fact that it has been increasingly used in combination with other films such as viewing angle correction films. As described above, until now, color spots have been reduced by adjusting various structures and physical properties of the film, but this method is not sufficient, and in addition to adjusting various structures and physical properties of the film, polymer It was concluded that it was necessary to control the structure to a certain range.
[0007]
Therefore, an object of the present invention is to provide a polyvinyl alcohol film that is useful as a raw material for producing a polarizing film that has good polarization performance and durability performance, little color spots, and can cope with an increase in the size of a liquid crystal display.
[0008]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have found that ethylene-modified polyvinyl alcohol having an ethylene unit content of 1 to 4 mol%, a polymerization degree of 2000 to 4000, and a saponification degree of 99.0 to 99.99 mol%. And an ethylene-modified polyvinyl alcohol film having a hot water cutting temperature of 66 to 73 ° C. was found, and the present invention was completed. This ethylene-modified polyvinyl alcohol film is excellent in polarization performance and durability performance, has few color spots, and is useful as a raw material for producing a polarization film that can cope with an increase in the size of a liquid crystal display.
In addition, the ethylene-modified polyvinyl alcohol film of the present invention is more preferably a difference in hot water cutting temperature between two points 5 cm away in the TD direction of the film is 1 ° C. or less in order to reduce color spots, The difference in hot water cutting temperature between two points 1 cm apart in the TD direction of the film is more preferably 0.5 ° C. or less in order to reduce color spots, and the film thickness is 10 to 50 μm. It is particularly preferable for reducing color spots.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
As the ethylene-modified polyvinyl alcohol (ethylene-modified PVA) used in the present invention, an ethylene-vinyl ester polymer obtained by copolymerizing ethylene and a vinyl ester monomer is saponified, and the vinyl ester unit is converted into a vinyl alcohol unit. Can be used. Examples of the vinyl ester monomers include vinyl formate, vinyl acetate, vinyl propionate, vinyl valelate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate, vinyl versatate, and the like. Of these, vinyl acetate is preferably used.
[0010]
The ethylene unit content (ethylene copolymerization amount) in the ethylene-modified PVA is 1 to 4 mol%, preferably 1.5 to 3 mol%, more preferably 2 to 3 mol%. When the content of the ethylene unit is less than 1 mol%, the effect of improving the polarization performance and durability performance and the effect of reducing color spots in the resulting polarizing film are reduced, which is not preferable. On the other hand, if the ethylene unit content exceeds 4 mol%, the affinity of ethylene-modified PVA with water is lowered, the uniformity of the film film surface is lowered, and it is liable to cause color spots on the polarizing film. It is.
[0011]
Further, when copolymerizing ethylene and a vinyl ester monomer, if necessary, the copolymerizable monomer is within a range not impairing the effects of the invention (preferably 15 mol% or less, more preferably 5 mol% or less. Can also be copolymerized.
[0012]
Examples of monomers copolymerizable with such vinyl ester monomers include olefins having 3 to 30 carbon atoms such as propylene, 1-butene and isobutene; acrylic acid and salts thereof; methyl acrylate, ethyl acrylate, Acrylic acid esters such as n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate, etc. Methacrylic acid and salts thereof; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-methacrylic acid 2- Ethylhexyl, dodecyl methacrylate, methacrylate Methacrylic acid esters such as octadecyl acid; acrylamide, N-methylacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide, diacetoneacrylamide, acrylamidepropanesulfonic acid and its salt, acrylamidopropyldimethylamine and its salt, N- Acrylamide derivatives such as methylolacrylamide and its derivatives; methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, methacrylamidepropanesulfonic acid and its salts, methacrylamidepropyldimethylamine and its salts, N-methylolmethacrylamide and its Methacrylamide derivatives such as derivatives; N-vinyl such as N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone Mido; Vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, stearyl vinyl ether; acrylonitrile, methacrylonitrile, etc. Nitriles; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl fluoride and vinylidene fluoride; allyl compounds such as allyl acetate and allyl chloride; maleic acid and its salts or esters; itaconic acid and its salts or its Esters; Vinylsilyl compounds such as vinyltrimethoxysilane; N-vinylamines such as isopropenyl acetate, N-vinylformamide, N-vinylacetamide, and N-vinylpyrrolidone Mention may be made of mids.
[0013]
The degree of polymerization of ethylene-modified PVA constituting the ethylene-modified PVA film is that the degree of polymerization of PVA of the polarizing film is 2000 to 4000, preferably 2200 to 3500, particularly preferably 2500 to 3000 from the viewpoint of polarization performance and durability. . When the degree of polymerization of ethylene-modified PVA is less than 2000, the polarizing performance and durability performance of the polarizing film are lowered, which is not preferable. On the other hand, if the degree of polymerization is greater than 4000, the productivity during polymerization is low and industrially unfavorable, and the affinity with water may be low, and the uniformity of the film film surface may be reduced, resulting in polarization. This is not preferable because it tends to cause color spots on the film.
[0014]
The degree of polymerization of the ethylene-modified PVA is a weight average degree of polymerization determined from GPC measurement. This weight average degree of polymerization is a value obtained by performing GPC measurement at 40 ° C. using hexafluoroisopropanol (HFIP) in which 20 mmol / liter sodium trifluoroacetate is added to the mobile phase using monodispersed PMMA as a standard. is there.
[0015]
The saponification degree of the ethylene-modified PVA constituting the ethylene-modified PVA film is 99.0 to 99.99 mol%, more preferably 99.9 to 99.99 mol%, from the viewpoint of the polarizing performance and durability of the polarizing film. 99.95-99.99 mol% is particularly preferable. When the saponification degree is lower than 99.0 mol%, the durability of the polarizing film is lowered, which is not preferable. On the other hand, when the degree of saponification exceeds 99.99 mol%, there is a problem such as coloring of the resin during the production of ethylene-modified PVA, and the production is accompanied with remarkable difficulty.
The saponification degree indicates the proportion of units that are actually saponified to vinyl alcohol units among units that can be converted to vinyl alcohol units by saponification. The saponification degree of ethylene-modified PVA was measured by the method described in JIS.
[0016]
As a method for producing an ethylene-modified PVA film using ethylene-modified PVA, in addition to a film forming method by a melt extrusion method using ethylene-modified PVA containing water, for example, an ethylene-modified PVA solution in which ethylene-modified PVA is dissolved in a solvent , Casting film forming method, wet film forming method (discharging into poor solvent), gel film forming method (after cooling and gelling ethylene-modified PVA aqueous solution, solvent is extracted and removed, ethylene-modified PVA A method for obtaining a film), a method using a combination of these, and the like can be employed. Among these, the casting film forming method and the melt extrusion film forming method are preferable from the viewpoint of obtaining a good ethylene-modified PVA film. The obtained ethylene-modified PVA film is subjected to drying and heat treatment as necessary.
[0017]
Examples of the solvent for dissolving the ethylene-modified PVA used in producing the ethylene-modified PVA film include dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, ethylene glycol, glycerin, propylene glycol, diethylene glycol, and triethylene. Glycol, tetraethylene glycol, trimethylolpropane, ethylenediamine, diethylenetriamine, glycerin, water and the like can be mentioned, and one or more of these can be used. Among these, dimethyl sulfoxide, water, or a mixed solvent of glycerin and water is preferably used.
[0018]
The ratio of ethylene-modified PVA in the ethylene-modified PVA solution or water-containing ethylene-modified PVA used in producing the ethylene-modified PVA film varies depending on the degree of polymerization of ethylene-modified PVA, but is preferably 20 to 70% by weight. 25 to 60% by weight is more preferred, 30 to 55% by weight is more preferred, and 35 to 50% by weight is most preferred. When the proportion of ethylene-modified PVA exceeds 70% by weight, the viscosity of ethylene-modified PVA solution or ethylene-modified PVA containing water becomes too high, making filtration and defoaming difficult when preparing a stock solution of the film. It is difficult to obtain a film without any defects. On the other hand, when the proportion of ethylene-modified PVA is lower than 20% by weight, the viscosity of ethylene-modified PVA containing ethylene-modified PVA solution or water becomes too low, and it becomes difficult to produce a PVA film having a desired thickness. Further, this ethylene-modified PVA solution or ethylene-modified PVA containing water may contain a plasticizer, a surfactant, a dichroic dye, or the like, if necessary.
[0019]
When producing an ethylene-modified PVA film, it is preferable to add a polyhydric alcohol as a plasticizer. Examples of the polyhydric alcohol include ethylene glycol, glycerin, propylene glycol, diethylene glycol, diglycerin, triethylene glycol, tetraethylene glycol, trimethylolpropane, etc., and one or more of these are used. can do. Among these, diglycerin, ethylene glycol, and glycerin are preferably used because of the effect of improving stretchability.
[0020]
The addition amount of the polyhydric alcohol is preferably 1 to 30 parts by weight, more preferably 3 to 25 parts by weight, and most preferably 5 to 20 parts by weight with respect to 100 parts by weight of the ethylene-modified PVA. When the amount is less than 1 part by weight, the dyeability and stretchability may be lowered. When the amount is more than 30 parts by weight, the ethylene-modified PVA film becomes too flexible and the handleability may be lowered.
[0021]
When producing an ethylene-modified PVA film, it is preferable to add a surfactant. The type of the surfactant is not particularly limited, but an anionic or nonionic surfactant is preferable. As the anionic surfactant, for example, a carboxylic acid type such as potassium laurate, a sulfate type such as octyl sulfate, and a sulfonic acid type anionic surfactant such as dodecylbenzenesulfonate are suitable. Nonionic surfactants include, for example, alkyl ether types such as polyoxyethylene oleyl ether, alkylphenyl ether types such as polyoxyethylene octylphenyl ether, alkyl ester types such as polyoxyethylene laurate, and polyoxyethylene laurylamino. Alkylamine type such as ether, alkylamide type such as polyoxyethylene lauric acid amide, polypropylene glycol ether type such as polyoxyethylene polyoxypropylene ether, alkanolamide type such as oleic acid diethanolamide, polyoxyalkylene allyl phenyl ether, etc. Nonionic surfactants such as allyl phenyl ether type are preferred. These surfactants can be used alone or in combination of two or more.
[0022]
The addition amount of the surfactant is preferably 0.01 to 1 part by weight, more preferably 0.02 to 0.5 part by weight, and 0.05 to 0.3 part by weight with respect to 100 parts by weight of the ethylene-modified PVA. Most preferred. If the amount is less than 0.01 parts by weight, the effect of improving the film forming property and peelability is hardly exhibited, and if the amount is more than 1 part by weight, the surfactant elutes on the surface of the ethylene-modified PVA film and causes blocking. May decrease.
[0023]
The hot water cutting temperature of the ethylene-modified PVA film of the present invention is 66 to 73 ° C, preferably 68 to 73 ° C, and more preferably 70 to 73 ° C. When the hot water cutting temperature of the ethylene-modified PVA film is lower than 66 ° C., the melted film is stretched and molecular orientation hardly occurs, so that the polarizing performance of the polarizing film becomes insufficient. When the hot water cutting temperature is higher than 73 ° C., the film is not easily stretched, and the polarizing performance of the polarizing film is lowered, which is not preferable.
When the ethylene-modified PVA film is subjected to drying and heat treatment, the hot water cutting temperature of the film can be adjusted by changing the temperature and time of the treatment.
[0024]
In the ethylene-modified PVA film of the present invention, the difference in hot water cutting temperature between two points 5 cm apart in the TD direction of the film is preferably 1 ° C. or less, more preferably 0.8 ° C. or less, It is particularly preferable that the temperature is not higher than 0.5 ° C. When the difference in hot water cutting temperature exceeds 1 ° C., color spots are likely to be noticeable when a polarizing film is prepared from an ethylene-modified PVA film, and color tone changes easily when incorporated into a liquid crystal display device. Absent. In order to set the difference in hot water cutting temperature between two points 5 cm apart to 1 ° C. or less, a known method for making the thermal history in the TD direction of the film uniform may be appropriately combined. For example, a method of making the resin temperature in the TD direction of the film, the drum temperature, the roll temperature, the drying temperature, the heat treatment temperature and the like uniform can be mentioned. In the present invention, even if the individual thermal history in the TD direction of the film is not uniform, the difference in hot water cutting temperature between two points 5 cm apart in the TD direction of the finally obtained film should be 1 ° C. or less. That's fine.
[0025]
In the ethylene-modified PVA film of the present invention, the difference in hot water cutting temperature between two points 1 cm away from each other in the TD direction of the film is preferably 0.5 ° C. or less, more preferably 0.4 ° C. or less. The temperature is preferably 0.3 ° C. or less. When the difference in hot water cutting temperature exceeds 0.5 ° C., color spots are easily noticeable when a polarizing film is prepared from an ethylene-modified PVA film, and color tone changes easily when incorporated in a liquid crystal display device. Therefore, it is not preferable. In order to set the difference in hot water cutting temperature between two points 1 cm apart to 0.5 ° C. or less, known methods for making the thermal history in the TD direction of the film uniform may be appropriately combined. For example, a method of making the resin temperature in the TD direction of the film, the drum temperature, the roll temperature, the drying temperature, the heat treatment temperature and the like uniform can be mentioned. In the present invention, even if the individual thermal history in the TD direction of the film is not uniform, the difference in hot water cutting temperature between two points 1 cm apart in the TD direction of the finally obtained film is 0.5 ° C. or less. If it is.
[0026]
The ethylene-modified PVA film of the present invention preferably has a thickness of 10 to 50 μm, and more preferably 20 to 40 μm. If the thickness is less than 10 μm, the film strength is too low to perform uniform stretching, and color spots of the polarizing film are likely to occur. When the thickness exceeds 50 μm, when a polarizing film is prepared by uniaxially stretching an ethylene-modified PVA film, a thickness change due to neck-in at the end tends to occur, and color spots of the polarizing film are easily emphasized, which is not preferable.
[0027]
In order to produce a polarizing film from the ethylene-modified PVA film of the present invention, for example, the ethylene-modified PVA film is dyed, uniaxially stretched, fixed, and dried, and further subjected to heat treatment as necessary. There is no restriction | limiting in particular in the order of operation of a uniaxial stretching and a fixing process. Moreover, you may perform uniaxial stretching twice or more.
[0028]
Dyeing can be performed before uniaxial stretching, during uniaxial stretching, or after uniaxial stretching. As dyes used for dyeing, iodine-potassium iodide; direct black 17, 19, 154; direct brown 44, 106, 195, 210, 223; direct red 2, 23, 28, 31, 37, 39, 79, 81 , 240, 242, 247; Direct Blue 1, 15, 22, 78, 90, 98, 151, 168, 202, 236, 249, 270; Direct Violet 9, 12, 51, 98; Direct Green 1, 85; Direct Dichroic dyes such as yellow 8, 12, 44, 86, 87; direct orange 26, 39, 106, 107 can be used in one kind or a mixture of two or more kinds. Ordinary dyeing is generally performed by immersing the PVA film in a solution containing the above-mentioned dye, but the processing conditions and processing method are particularly limited, such as mixing with the PVA film to form a film. is not.
[0029]
For uniaxial stretching, wet stretching or dry heat stretching can be used, using warm water such as an aqueous boric acid solution (in a solution containing the dye or in a fixing treatment bath described later) or an ethylene-modified PVA film after water absorption. Can be done in air. The stretching temperature is not particularly limited, but is preferably 30 to 90 ° C. when the ethylene-modified PVA film is stretched (wet stretching) in warm water, and 50 to 180 ° C. is suitable for dry heat stretching. Further, the stretching ratio of uniaxial stretching (the total stretching ratio in the case of multi-stage uniaxial stretching) is preferably 4 times or more, and most preferably 5 times or more from the viewpoint of the polarizing performance of the polarizing film. The upper limit of the stretching ratio is not particularly limited, but it is preferably 8 times or less because uniform stretching is easily obtained. 2-20 micrometers is preferable and, as for the thickness of the film after extending | stretching, 5-15 micrometers is more preferable.
[0030]
Fixing treatment is often performed for the purpose of strengthening the adsorption of the dye to the ethylene-modified PVA film. Usually, boric acid and / or boron compounds are added to the treatment bath used for the fixing treatment. Moreover, you may add an iodine compound in a processing bath as needed.
[0031]
It is preferable to perform the drying process of the obtained polarizing film at 30-150 degreeC, and it is more preferable to carry out at 50-150 degreeC.
[0032]
The polarizing film obtained as described above is usually used as a polarizing plate by attaching a protective film optically transparent and having mechanical strength on both sides or one side. As the protective film, a cellulose triacetate (TAC) film, an acetic acid / cellulose butyrate (CAB) film, an acrylic film, a polyester film, or the like is used. In addition, examples of the adhesive for bonding include a PVA-based adhesive and a urethane-based adhesive, among which a PVA-based adhesive is preferable.
[0033]
The polarizing plate obtained as described above is coated with an acrylic adhesive or the like and then bonded to a glass substrate and used as a component of a liquid crystal display device, or a retardation film, a viewing angle improving film, a brightness improving film. Etc. and used together.
[0034]
【Example】
Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, the hot-water cutting temperature in an Example, the transmittance | permeability of a polarizing film, a polarization degree, and dichroism ratio were evaluated with the following method.
[0035]
Hot water cutting temperature measurement
The ethylene-modified PVA film was cut into a length of 5 cm and a width of 5 mm in the width direction. 1mm cross-sectional area in the width direction at the bottom of the film 2 A weight of 1 g per hit was attached and hung in water. Water was heated at a rate of 3 ° C. per minute, and the temperature at which the film dissolved and cut was measured.
Measurement of transmittance, polarization degree and dichroic ratio of polarizing film:
Using a spectrophotometer UV-2200 (attached to an integrating sphere) manufactured by Shimadzu Corporation, the polarizing film is measured with a C light source and a two-degree field of view according to the Japan Electronic Machinery Manufacturers Association (EIAJ) LD-201-1983. The transmittance (T) and the degree of polarization (V) were obtained by calculation. Further, the dichroic ratio (Rd) was determined from the following equation as needed.
Rd = log (T−T × V) / log (T + T × V)
[0036]
Example 1
100 parts by weight of ethylene-modified PVA having an ethylene unit content of 2.5 mol%, a saponification degree of 99.95 mol%, and a polymerization degree of 2400 is melt-kneaded and impregnated with 10 parts by weight of glycerin and 170 parts by weight of water. After foaming, it was melt-extruded from a T die to a metal roll to form a film. The ethylene-modified PVA film obtained after drying and heat treatment had a thickness of 40 μm, and the average hot water cutting temperature of the film was 70 ° C.
[0037]
The ethylene-modified PVA film thus obtained was continuously processed in the order of pre-swelling, dyeing, uniaxial stretching, fixing treatment, drying, and heat treatment to prepare a polarizing film. That is, the ethylene-modified PVA film is pre-swelled by immersing in 30 ° C. water for 60 seconds, and is immersed in a 35 ° C. aqueous solution having a boric acid concentration of 40 g / liter, an iodine concentration of 0.4 g / liter, and a potassium iodide concentration of 60 g / liter. Soaked for 2 minutes. Subsequently, it was uniaxially stretched 6 times in an aqueous solution at 55 ° C. with a boric acid concentration of 4%, and in an aqueous solution at 30 ° C. with a potassium iodide concentration of 60 g / liter, a boric acid concentration of 40 g / liter, and a zinc chloride concentration of 10 g / liter. For 5 minutes, and fixed. Thereafter, the ethylene-modified PVA film was taken out, dried with hot air at 40 ° C. under a constant length, and further subjected to heat treatment at 100 ° C. for 5 minutes.
[0038]
The transmittance of the obtained polarizing film was 44.34%, the degree of polarization was 99.46%, and the dichroic ratio determined by calculation was 49.13. When the obtained polarizing film was placed at an angle of 10 degrees between two polarizing plates arranged in parallel to the stretching axis direction (0 degree), the central part and the end part of the polarizing film in the width direction. The difference in luminance was small, and the color spots were small and good. The direction in which this was uniaxially stretched was fixed, and a moisture and heat resistance test was performed in an environment of 60 ° C. and 90% RH. The transmittance of the polarizing film after 24 hours was 46.50%, the degree of polarization was 91.24%, and the dichroic ratio determined by calculation was 27.27.
[0039]
A polarizing plate was obtained by bonding a triacetate film to the obtained polarizing film using a 4% polyvinyl alcohol aqueous solution. The obtained polarizing plate was placed at an angle of 10 degrees between two polarizing plates arranged in parallel to the stretching axis direction (0 degree). The difference in luminance was small, and the color spots were small and good.
[0040]
Example 2
100 parts by weight of ethylene-modified PVA having an ethylene unit content of 2.1 mol%, a saponification degree of 99.92 mol%, and a polymerization degree of 3000 is impregnated with 10 parts by weight of glycerin and 200 parts by weight of water, and kneaded. After foaming, it was melt-extruded from a T die to a metal roll to form a film. The thickness of the ethylene-modified PVA film obtained after drying and heat treatment was 35 μm, and the average hot water cutting temperature of the film was 68 ° C.
[0041]
The ethylene-modified PVA film thus obtained was continuously processed in the order of pre-swelling, dyeing, uniaxial stretching, fixing treatment, drying, and heat treatment to prepare a polarizing film. That is, the ethylene-modified PVA film is pre-swelled by immersing it in water at 30 ° C. for 60 seconds and placed in a 35 ° C. aqueous solution having a boric acid concentration of 40 g / liter, an iodine concentration of 0.4 g / liter, and a potassium iodide concentration of 60 g / liter. Soaked for 2 minutes. Subsequently, it was uniaxially stretched 6 times in an aqueous solution at 55 ° C. with a boric acid concentration of 4%, and in an aqueous solution at 30 ° C. with a potassium iodide concentration of 60 g / liter, a boric acid concentration of 40 g / liter, and a zinc chloride concentration of 10 g / liter. For 5 minutes, and fixed. Thereafter, the ethylene-modified PVA film was taken out, dried with hot air at 40 ° C. under a constant length, and further subjected to heat treatment at 100 ° C. for 5 minutes.
[0042]
The transmittance of the obtained polarizing film was 43.63%, the degree of polarization was 99.85%, and the dichroic ratio determined by calculation was 53.51. When the obtained polarizing film was placed at an angle of 10 degrees between two polarizing plates arranged in parallel to the stretching axis direction (0 degree), the central part and the end part of the polarizing film in the width direction. The difference in luminance was small, and the color spots were small and good. The direction in which this was uniaxially stretched was fixed, and a moisture and heat resistance test was performed in an environment of 60 ° C. and 90% RH. The transmittance of the polarizing film after 24 hours was 45.21%, the degree of polarization was 96.82%, and the dichroic ratio determined by calculation was 36.34.
[0043]
A polarizing plate was obtained by bonding a triacetate film to the obtained polarizing film using a 4% polyvinyl alcohol aqueous solution. The obtained polarizing plate was placed at an angle of 10 degrees between two polarizing plates arranged in parallel to the stretching axis direction (0 degree). The difference in luminance was small, and the color spots were small and good.
[0044]
Comparative Example 1
100 parts by weight of PVA having a saponification degree of 99.95 mol% and a polymerization degree of 2400 was melt-kneaded with 10 parts by weight of glycerin and 170 parts by weight of water, and after defoaming, melt extrusion from a T die to a metal roll was performed. Filmed. The thickness of the PVA film obtained after drying and heat treatment was 40 μm, and the average hot water cutting temperature of the film was 70 ° C.
[0045]
The PVA film was continuously processed in the order of preliminary swelling, dyeing, uniaxial stretching, fixing treatment, drying, and heat treatment to prepare a polarizing film. That is, the PVA film is pre-swelled by immersing it in water at 30 ° C. for 60 seconds, and is placed in a 35 ° C. aqueous solution having a boric acid concentration of 40 g / liter, an iodine concentration of 0.4 g / liter, and a potassium iodide concentration of 40 g / liter for 2 minutes. Soaked. Subsequently, uniaxial stretching was performed 5.8 times in a 55 ° C. aqueous solution having a boric acid concentration of 4%, and the potassium iodide concentration was 40 g / liter, the boric acid concentration was 40 g / liter, and the zinc chloride concentration was 10 g / liter. Fixing was performed by immersing in an aqueous solution for 5 minutes. Thereafter, the PVA film was taken out, dried with hot air at 40 ° C. under a constant length, and further subjected to heat treatment at 100 ° C. for 5 minutes.
[0046]
The transmittance of the obtained polarizing film was 43.52%, the degree of polarization was 99.76%, and the dichroic ratio determined by calculation was 49.03. When the obtained polarizing film was placed at an angle of 10 degrees between two polarizing plates arranged in parallel to the stretching axis direction (0 degree), the central part and the end part of the polarizing film in the width direction. The difference in luminance was large and color spots were large, which was a poor polarizing film for large liquid crystal displays. The direction in which this was uniaxially stretched was fixed, and a moisture and heat resistance test was performed in an environment of 60 ° C. and 90% RH. The transmittance of the polarizing film after 24 hours was 47.9%, the degree of polarization was 85.51%, and the dichroic ratio determined by calculation was 22.93.
[0047]
A triacetate film was bonded to the obtained polarizing film using a 4% polyvinyl alcohol aqueous solution to obtain a polarizing plate. The obtained polarizing plate was placed at an angle of 10 degrees between two polarizing plates arranged in parallel to the stretching axis direction (0 degree). The difference in luminance was large and color spots were large, which was a poor polarizing film for large liquid crystal displays.
[0048]
Comparative Example 2
100 parts by weight of ethylene-modified PVA having an ethylene unit content of 2.5 mol%, a saponification degree of 99.95 mol%, and a polymerization degree of 2400 is melt-kneaded and impregnated with 10 parts by weight of glycerin and 170 parts by weight of water. After foaming, it was melt-extruded from a T die to a metal roll to form a film. The thickness of the ethylene-modified PVA film obtained after drying and heat treatment was 40 μm, and the average hot water cutting temperature of the film was 75 ° C.
[0049]
The ethylene-modified PVA film thus obtained was continuously treated in the order of pre-swelling, dyeing, uniaxial stretching, fixing treatment, drying, and heat treatment to prepare a polarizing film. That is, the ethylene-modified PVA film is pre-swelled by immersing in 30 ° C. water for 60 seconds, and is immersed in a 35 ° C. aqueous solution having a boric acid concentration of 40 g / liter, an iodine concentration of 0.4 g / liter, and a potassium iodide concentration of 60 g / liter. Soaked for 2 minutes. Subsequently, uniaxial stretching was performed 5.8 times in a 60 ° C. aqueous solution with a boric acid concentration of 4%, and 30 ° C. with a potassium iodide concentration of 60 g / liter, a boric acid concentration of 40 g / liter, and a zinc chloride concentration of 10 g / liter. Fixing was performed by immersing in an aqueous solution for 5 minutes. Thereafter, the ethylene-modified PVA film was taken out, dried with hot air at 40 ° C. under a constant length, and further subjected to heat treatment at 100 ° C. for 5 minutes.
[0050]
The transmittance of the obtained polarizing film was 52.36%, the degree of polarization was 73.04%, and the dichroic ratio determined by calculation was 19.82. When the obtained polarizing film was placed at an angle of 10 degrees between two polarizing plates arranged in parallel to the stretching axis direction (0 degree), the central part and the end part of the polarizing film in the width direction. The difference in brightness was large, and the color spots were large, which was a poor polarizing film for large liquid crystal displays. The direction in which this was uniaxially stretched was fixed, and a moisture and heat resistance test was performed in an environment of 60 ° C. and 90% RH. The transmittance of the polarizing film after 24 hours was 85.49%, the degree of polarization was 12.62%, and the dichroic ratio determined by calculation was 7.69.
[0051]
The obtained polarizing film was bonded to a triacetate film using a 4% polyvinyl alcohol aqueous solution to obtain a polarizing plate. The obtained polarizing plate was placed at an angle of 10 degrees between two polarizing plates arranged in parallel to the stretching axis direction (0 degree). The difference in luminance was large and color spots were large, which was a poor polarizing film for large liquid crystal displays.
[0052]
Comparative Example 3
100 parts by weight of ethylene-modified PVA having an ethylene unit content of 2.5 mol%, a saponification degree of 99.95 mol%, and a polymerization degree of 2400 is melt-kneaded and impregnated with 10 parts by weight of glycerin and 170 parts by weight of water. After foaming, it was melt-extruded from a T die to a metal roll to form a film. The thickness of the ethylene-modified PVA film obtained after drying and heat treatment was 40 μm, and the average hot water cutting temperature of the film was 65 ° C.
[0053]
The ethylene-modified PVA film thus obtained was continuously treated in the order of pre-swelling, dyeing, uniaxial stretching, fixing treatment, drying, and heat treatment to prepare a polarizing film. That is, the ethylene-modified PVA film is pre-swelled by immersing in 30 ° C. water for 60 seconds, and is immersed in a 35 ° C. aqueous solution having a boric acid concentration of 40 g / liter, an iodine concentration of 0.4 g / liter, and a potassium iodide concentration of 60 g / liter. Soaked for 2 minutes. Subsequently, uniaxial stretching was performed 5.8 times in a 60 ° C. aqueous solution with a boric acid concentration of 4%, and the potassium iodide concentration was 50 g / liter, the boric acid concentration was 40 g / liter, and the zinc chloride concentration was 10 g / liter. Fixing was performed by immersing in an aqueous solution for 5 minutes. Thereafter, the ethylene-modified PVA film was taken out, dried with hot air at 40 ° C. under a constant length, and further subjected to heat treatment at 100 ° C. for 5 minutes.
[0054]
The transmittance of the obtained polarizing film was 44.34%, the degree of polarization was 98.42%, and the dichroic ratio determined by calculation was 38.78. When the obtained polarizing film was placed at an angle of 10 degrees between two polarizing plates arranged in parallel to the stretching axis direction (0 degree), the central part and the end part of the polarizing film in the width direction. The difference in luminance was large and color spots were large, which was a poor polarizing film for large liquid crystal displays. The direction in which this was uniaxially stretched was fixed, and a moisture and heat resistance test was performed in an environment of 60 ° C. and 90% RH. The transmittance of the polarizing film after 24 hours was 53.03%, the degree of polarization was 35.12%, and the dichroic ratio determined by calculation was 3.20.
[0055]
A triacetate film was bonded to the obtained polarizing film using a 4% polyvinyl alcohol aqueous solution to obtain a polarizing plate. The obtained polarizing plate was placed at an angle of 10 degrees between two polarizing plates arranged in parallel to the stretching axis direction (0 degree). The difference in luminance was large and color spots were large, which was a poor polarizing film for large liquid crystal displays.
[0056]
Comparative Example 4
100 parts by weight of ethylene-modified PVA having an ethylene content of 2.5 mol%, a saponification degree of 99.95 mol%, and a degree of polymerization of 1700 is impregnated with 10 parts by weight of glycerin and 170 parts by weight of water, and after degassing The film was melt-extruded from a T die to a metal roll to form a film. The thickness of the ethylene-modified PVA film obtained after drying and heat treatment was 40 μm, and the average hot water cutting temperature of the film was 70 ° C.
[0057]
The ethylene-modified PVA film thus obtained was successively treated in the order of pre-swelling, dyeing, uniaxial stretching, fixing treatment, drying, and heat treatment to prepare a polarizing film. That is, the ethylene-modified PVA film is pre-swelled by immersing in 30 ° C. water for 60 seconds, and is immersed in a 35 ° C. aqueous solution having a boric acid concentration of 40 g / liter, an iodine concentration of 0.4 g / liter, and a potassium iodide concentration of 60 g / liter. Soaked for 2 minutes. Subsequently, uniaxial stretching was performed 5.8 times in a 60 ° C. aqueous solution with a boric acid concentration of 4%, and 30 ° C. with a potassium iodide concentration of 60 g / liter, a boric acid concentration of 40 g / liter, and a zinc chloride concentration of 10 g / liter. Fixing was performed by immersing in an aqueous solution for 5 minutes. Thereafter, the ethylene-modified PVA film was taken out, dried with hot air at 40 ° C. under a constant length, and further subjected to heat treatment at 100 ° C. for 5 minutes.
[0058]
The transmittance of the obtained polarizing film was 43.61%, the degree of polarization was 99.75%, and the dichroic ratio determined by calculation was 49.43. When the obtained polarizing film was placed at an angle of 10 degrees between two polarizing plates arranged in parallel to the stretching axis direction (0 degree), the central part and the end part of the polarizing film in the width direction. The difference in luminance was large and color spots were large, which was a poor polarizing film for large liquid crystal displays. The direction in which this was uniaxially stretched was fixed, and a moisture and heat resistance test was performed in an environment of 60 ° C. and 90% RH. The transmittance of the polarizing film after 24 hours was 55.98%, the degree of polarization was 30.05%, and the dichroic ratio determined by calculation was 2.95.
[0059]
A triacetate film was bonded to the obtained polarizing film using a 4% polyvinyl alcohol aqueous solution to obtain a polarizing plate. The obtained polarizing plate was placed at an angle of 10 degrees between two polarizing plates arranged in parallel to the stretching axis direction (0 degree). The difference in luminance was large and color spots were large, which was a poor polarizing film for large liquid crystal displays.
[0060]
Comparative Example 5
100 parts by weight of ethylene-modified PVA having an ethylene content of 2.5 mol%, a degree of saponification of 98.5 mol%, and a degree of polymerization of 2400 was melt-kneaded with 10 parts by weight of glycerin and 170 parts by weight of water, and after degassing The film was melt-extruded from a T die to a metal roll to form a film. The thickness of the ethylene-modified PVA film obtained after drying and heat treatment was 40 μm, and the average hot water cutting temperature of the film was 70 ° C.
[0061]
The ethylene-modified PVA film thus obtained was continuously processed in the order of pre-swelling, dyeing, uniaxial stretching, fixing treatment, drying, and heat treatment to prepare a polarizing film. That is, the ethylene-modified PVA film is pre-swelled by immersing it in water at 30 ° C. for 60 seconds. Soaked for a minute. Subsequently, uniaxial stretching was performed 5.9 times in a 60 ° C. aqueous solution with a boric acid concentration of 4%. Fixing was performed by immersing in an aqueous solution for 5 minutes. Thereafter, the ethylene-modified PVA film was taken out, dried with hot air at 40 ° C. under a constant length, and further subjected to heat treatment at 100 ° C. for 5 minutes.
[0062]
The transmittance of the obtained polarizing film was 44.23%, the degree of polarization was 99.48%, and the dichroic ratio determined by calculation was 48.51. When the obtained polarizing film was placed at an angle of 10 degrees between two polarizing plates arranged in parallel to the stretching axis direction (0 degree), the central part and the end part of the polarizing film in the width direction. The difference in luminance was large and color spots were large, which was a poor polarizing film for large liquid crystal displays. The direction in which this was uniaxially stretched was fixed, and a moisture and heat resistance test was performed in an environment of 60 ° C. and 90% RH. The transmittance of the polarizing film after 24 hours was 55.01%, the degree of polarization was 37.51%, and the dichroic ratio determined by calculation was 3.83.
[0063]
The obtained polarizing film was bonded to a triacetate film using a 4% polyvinyl alcohol aqueous solution to obtain a polarizing plate. The obtained polarizing plate was placed at an angle of 10 degrees between two polarizing plates arranged in parallel to the stretching axis direction (0 degree). The difference in luminance was large and color spots were large, which was a poor polarizing film for large liquid crystal displays.
[0064]
Example 3
In Example 1, an ethylene-modified PVA film was prepared in the same manner as in Example 1 except that the heat history in the width direction was changed. The average value of the hot water cutting temperature of the obtained film was 70 ° C., and the hot water cutting temperature in the width direction of the film was measured every 1 cm in width. The difference in hot water cutting temperature was 0.4 ° C. at the largest place, and the difference in hot water cutting temperature between two points 1 cm apart in the TD direction of the film was 0.2 ° C. Using this film, a polarizing film was prepared in the same manner as in Example 1. As a result, the color spots by visual observation were very small and very good.
[0065]
Example 4
In Example 1, an ethylene-modified PVA film was prepared in the same manner as in Example 1 except that the heat history in the width direction was changed. The average value of the hot water cutting temperature of the obtained film was 70 ° C., and the hot water cutting temperature in the width direction of the film was measured every 1 cm in width. The difference in hot water cutting temperature was 0.6 ° C. at the largest location, and the difference in hot water cutting temperature between two points 1 cm apart in the TD direction of the film was 0.3 ° C. at the largest location. Using this film, a polarizing film was prepared in the same manner as in Example 1. As a result, the color spots by visual observation were small and good.
[0066]
Example 5
In Example 1, an ethylene-modified PVA film was prepared in the same manner as in Example 1 except that the heat history in the width direction was changed. The average value of the hot water cutting temperature of the obtained film was 70 ° C., and the hot water cutting temperature in the width direction of the film was measured every 1 cm in width. The difference in hot water cutting temperature was 0.9 ° C. at the largest location, and the difference in hot water cutting temperature between two points 1 cm apart in the TD direction of the film was 0.5 ° C. at the largest location. Using this film, a polarizing film was produced in the same manner as in Example 1. As a result, the color spots by visual observation were small and usable.
[0067]
【The invention's effect】
According to the present invention, it is possible to obtain an ethylene-modified PVA film that has good polarization performance when made into a polarizing film and can reduce color spots. And using this ethylene modified PVA film, there can be obtained a polarizing film suitable for a large-sized liquid crystal display with few color spots.
Claims (4)
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| JP2002078889A JP4101540B2 (en) | 2002-03-20 | 2002-03-20 | Ethylene-modified polyvinyl alcohol film |
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| Application Number | Priority Date | Filing Date | Title |
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| JP2002078889A JP4101540B2 (en) | 2002-03-20 | 2002-03-20 | Ethylene-modified polyvinyl alcohol film |
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| US7479312B2 (en) * | 2005-07-07 | 2009-01-20 | Konica Minolta Opto, Inc. | Retardation film, polarizing plate, and liquid crystal display device |
| KR100837427B1 (en) * | 2006-06-30 | 2008-06-12 | 주식회사 엘지화학 | Polyvinylalcohol film and polarizing film |
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