CN116547345A - Polyvinyl alcohol film, and polarizing film and polarizing plate using same - Google Patents
Polyvinyl alcohol film, and polarizing film and polarizing plate using same Download PDFInfo
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- CN116547345A CN116547345A CN202180079402.3A CN202180079402A CN116547345A CN 116547345 A CN116547345 A CN 116547345A CN 202180079402 A CN202180079402 A CN 202180079402A CN 116547345 A CN116547345 A CN 116547345A
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- Prior art keywords
- film
- pva
- pva film
- mass
- stretching
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- 239000004372 Polyvinyl alcohol Substances 0.000 title claims abstract description 226
- 229920002451 polyvinyl alcohol Polymers 0.000 title claims abstract description 226
- 239000010408 film Substances 0.000 claims abstract description 315
- 238000005481 NMR spectroscopy Methods 0.000 claims abstract description 28
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 claims abstract description 24
- 239000004327 boric acid Substances 0.000 claims abstract description 24
- 239000007864 aqueous solution Substances 0.000 claims abstract description 19
- 239000012788 optical film Substances 0.000 claims abstract description 16
- 230000008961 swelling Effects 0.000 claims description 35
- 239000013078 crystal Substances 0.000 claims description 9
- 238000006116 polymerization reaction Methods 0.000 claims description 9
- 230000001681 protective effect Effects 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 abstract description 23
- 238000011282 treatment Methods 0.000 description 153
- 239000007788 liquid Substances 0.000 description 81
- 238000000034 method Methods 0.000 description 57
- 238000001035 drying Methods 0.000 description 38
- 206010042674 Swelling Diseases 0.000 description 34
- 238000004043 dyeing Methods 0.000 description 33
- 239000011550 stock solution Substances 0.000 description 33
- NLKNQRATVPKPDG-UHFFFAOYSA-M potassium iodide Chemical compound [K+].[I-] NLKNQRATVPKPDG-UHFFFAOYSA-M 0.000 description 30
- 238000004132 cross linking Methods 0.000 description 29
- 150000001875 compounds Chemical class 0.000 description 27
- 238000010438 heat treatment Methods 0.000 description 22
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 21
- 238000004140 cleaning Methods 0.000 description 20
- 239000004094 surface-active agent Substances 0.000 description 17
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical compound [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 description 16
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 16
- 229910052796 boron Inorganic materials 0.000 description 16
- 229910052740 iodine Inorganic materials 0.000 description 16
- 239000011630 iodine Substances 0.000 description 16
- -1 ethylene, propylene, 1-butene Chemical class 0.000 description 15
- 239000000178 monomer Substances 0.000 description 15
- 239000004014 plasticizer Substances 0.000 description 11
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 description 10
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 10
- 229920001290 polyvinyl ester Polymers 0.000 description 9
- 239000000243 solution Substances 0.000 description 9
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 8
- 238000005259 measurement Methods 0.000 description 8
- 238000005406 washing Methods 0.000 description 8
- 239000004973 liquid crystal related substance Substances 0.000 description 7
- 239000002994 raw material Substances 0.000 description 7
- 229920001567 vinyl ester resin Polymers 0.000 description 7
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 description 6
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 6
- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 6
- 239000003431 cross linking reagent Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 239000000155 melt Substances 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- 238000007127 saponification reaction Methods 0.000 description 6
- 239000002904 solvent Substances 0.000 description 6
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 6
- 238000005266 casting Methods 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- 230000005281 excited state Effects 0.000 description 5
- 238000001125 extrusion Methods 0.000 description 5
- 238000001914 filtration Methods 0.000 description 5
- 230000010287 polarization Effects 0.000 description 5
- 229920000642 polymer Polymers 0.000 description 5
- 150000003839 salts Chemical class 0.000 description 5
- 230000003068 static effect Effects 0.000 description 5
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 4
- 239000005977 Ethylene Substances 0.000 description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 4
- 239000000853 adhesive Substances 0.000 description 4
- 230000001070 adhesive effect Effects 0.000 description 4
- 238000007664 blowing Methods 0.000 description 4
- 229910021538 borax Inorganic materials 0.000 description 4
- 235000011187 glycerol Nutrition 0.000 description 4
- 229910052739 hydrogen Inorganic materials 0.000 description 4
- 239000001257 hydrogen Substances 0.000 description 4
- 239000004328 sodium tetraborate Substances 0.000 description 4
- 235000010339 sodium tetraborate Nutrition 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 239000002981 blocking agent Substances 0.000 description 3
- 238000004090 dissolution Methods 0.000 description 3
- 230000001771 impaired effect Effects 0.000 description 3
- 230000001965 increasing effect Effects 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- 150000003460 sulfonic acids Chemical class 0.000 description 3
- 229920002554 vinyl polymer Polymers 0.000 description 3
- IKHGUXGNUITLKF-UHFFFAOYSA-N Acetaldehyde Chemical compound CC=O IKHGUXGNUITLKF-UHFFFAOYSA-N 0.000 description 2
- ZTQSAGDEMFDKMZ-UHFFFAOYSA-N Butyraldehyde Chemical compound CCCC=O ZTQSAGDEMFDKMZ-UHFFFAOYSA-N 0.000 description 2
- 229920002284 Cellulose triacetate Polymers 0.000 description 2
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 description 2
- IMROMDMJAWUWLK-UHFFFAOYSA-N Ethenol Chemical group OC=C IMROMDMJAWUWLK-UHFFFAOYSA-N 0.000 description 2
- DKNPRRRKHAEUMW-UHFFFAOYSA-N Iodine aqueous Chemical compound [K+].I[I-]I DKNPRRRKHAEUMW-UHFFFAOYSA-N 0.000 description 2
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 description 2
- AOMUHOFOVNGZAN-UHFFFAOYSA-N N,N-bis(2-hydroxyethyl)dodecanamide Chemical compound CCCCCCCCCCCC(=O)N(CCO)CCO AOMUHOFOVNGZAN-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
- 150000001241 acetals Chemical group 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 150000008064 anhydrides Chemical class 0.000 description 2
- 239000003945 anionic surfactant Substances 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 2
- 125000004432 carbon atom Chemical group C* 0.000 description 2
- 229920006217 cellulose acetate butyrate Polymers 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- ILRSCQWREDREME-UHFFFAOYSA-N dodecanamide Chemical compound CCCCCCCCCCCC(N)=O ILRSCQWREDREME-UHFFFAOYSA-N 0.000 description 2
- 230000002708 enhancing effect Effects 0.000 description 2
- 150000002148 esters Chemical class 0.000 description 2
- FJKIXWOMBXYWOQ-UHFFFAOYSA-N ethenoxyethane Chemical compound CCOC=C FJKIXWOMBXYWOQ-UHFFFAOYSA-N 0.000 description 2
- 150000002170 ethers Chemical class 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 229940031957 lauric acid diethanolamide Drugs 0.000 description 2
- 230000005415 magnetization Effects 0.000 description 2
- 239000002736 nonionic surfactant Substances 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 150000002894 organic compounds Chemical class 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- ILJSQTXMGCGYMG-UHFFFAOYSA-N triacetic acid Chemical compound CC(=O)CC(=O)CC(O)=O ILJSQTXMGCGYMG-UHFFFAOYSA-N 0.000 description 2
- ZIBGPFATKBEMQZ-UHFFFAOYSA-N triethylene glycol Chemical compound OCCOCCOCCO ZIBGPFATKBEMQZ-UHFFFAOYSA-N 0.000 description 2
- 230000037303 wrinkles Effects 0.000 description 2
- 239000004711 α-olefin Substances 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
- OZCMOJQQLBXBKI-UHFFFAOYSA-N 1-ethenoxy-2-methylpropane Chemical compound CC(C)COC=C OZCMOJQQLBXBKI-UHFFFAOYSA-N 0.000 description 1
- UZKWTJUDCOPSNM-UHFFFAOYSA-N 1-ethenoxybutane Chemical compound CCCCOC=C UZKWTJUDCOPSNM-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
- 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
- PGYJSURPYAAOMM-UHFFFAOYSA-N 2-ethenoxy-2-methylpropane Chemical compound CC(C)(C)OC=C PGYJSURPYAAOMM-UHFFFAOYSA-N 0.000 description 1
- GNUGVECARVKIPH-UHFFFAOYSA-N 2-ethenoxypropane Chemical compound CC(C)OC=C GNUGVECARVKIPH-UHFFFAOYSA-N 0.000 description 1
- 125000003903 2-propenyl group Chemical group [H]C([*])([H])C([H])=C([H])[H] 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
- RPNUMPOLZDHAAY-UHFFFAOYSA-N Diethylenetriamine Chemical compound NCCNCCN RPNUMPOLZDHAAY-UHFFFAOYSA-N 0.000 description 1
- SNRUBQQJIBEYMU-UHFFFAOYSA-N Dodecane Natural products CCCCCCCCCCCC SNRUBQQJIBEYMU-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
- VQTUBCCKSQIDNK-UHFFFAOYSA-N Isobutene Chemical group CC(C)=C VQTUBCCKSQIDNK-UHFFFAOYSA-N 0.000 description 1
- HETCEOQFVDFGSY-UHFFFAOYSA-N Isopropenyl acetate Chemical group CC(=C)OC(C)=O HETCEOQFVDFGSY-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
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 1
- WHNWPMSKXPGLAX-UHFFFAOYSA-N N-Vinyl-2-pyrrolidone Chemical compound C=CN1CCCC1=O WHNWPMSKXPGLAX-UHFFFAOYSA-N 0.000 description 1
- 208000012868 Overgrowth Diseases 0.000 description 1
- 229920006197 POE laurate Polymers 0.000 description 1
- 238000006124 Pilkington process Methods 0.000 description 1
- OFOBLEOULBTSOW-UHFFFAOYSA-N Propanedioic acid Natural products OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 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
- 150000003926 acrylamides Chemical class 0.000 description 1
- 239000003522 acrylic cement Substances 0.000 description 1
- 230000000996 additive effect Effects 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
- 238000004458 analytical method Methods 0.000 description 1
- 239000007798 antifreeze agent Substances 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
- 230000003078 antioxidant effect Effects 0.000 description 1
- 239000012736 aqueous medium Substances 0.000 description 1
- 230000000740 bleeding effect Effects 0.000 description 1
- 150000001639 boron compounds Chemical class 0.000 description 1
- 150000007942 carboxylates Chemical group 0.000 description 1
- 150000001732 carboxylic acid derivatives Chemical group 0.000 description 1
- 150000001735 carboxylic acids Chemical class 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000001413 cellular effect Effects 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 230000003750 conditioning effect Effects 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- SWXVUIWOUIDPGS-UHFFFAOYSA-N diacetone alcohol Chemical compound CC(=O)CC(C)(C)O SWXVUIWOUIDPGS-UHFFFAOYSA-N 0.000 description 1
- 229940105990 diglycerin Drugs 0.000 description 1
- GPLRAVKSCUXZTP-UHFFFAOYSA-N diglycerol Chemical compound OCC(O)COCC(O)CO GPLRAVKSCUXZTP-UHFFFAOYSA-N 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 239000012153 distilled water Substances 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
- 125000003438 dodecyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 229940071161 dodecylbenzenesulfonate Drugs 0.000 description 1
- 238000010828 elution Methods 0.000 description 1
- 230000007613 environmental effect Effects 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
- MEGHWIAOTJPCHQ-UHFFFAOYSA-N ethenyl butanoate Chemical compound CCCC(=O)OC=C MEGHWIAOTJPCHQ-UHFFFAOYSA-N 0.000 description 1
- GLVVKKSPKXTQRB-UHFFFAOYSA-N ethenyl dodecanoate Chemical group 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 group 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
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- XUCNUKMRBVNAPB-UHFFFAOYSA-N fluoroethene Chemical compound FC=C XUCNUKMRBVNAPB-UHFFFAOYSA-N 0.000 description 1
- 230000008014 freezing Effects 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 230000003993 interaction Effects 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
- 125000001449 isopropyl group Chemical group [H]C([H])([H])C([H])(*)C([H])([H])[H] 0.000 description 1
- 229940116335 lauramide Drugs 0.000 description 1
- VZCYOOQTPOCHFL-UPHRSURJSA-N maleic acid Chemical compound OC(=O)\C=C/C(O)=O VZCYOOQTPOCHFL-UPHRSURJSA-N 0.000 description 1
- 239000011976 maleic acid Substances 0.000 description 1
- 230000000873 masking effect Effects 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 239000002609 medium Substances 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 1
- XJRBAMWJDBPFIM-UHFFFAOYSA-N methyl vinyl ether Chemical compound COC=C XJRBAMWJDBPFIM-UHFFFAOYSA-N 0.000 description 1
- LVHBHZANLOWSRM-UHFFFAOYSA-N methylenebutanedioic acid Natural products OC(=O)CC(=C)C(O)=O LVHBHZANLOWSRM-UHFFFAOYSA-N 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- QQGJWWNPACORPU-UHFFFAOYSA-N n,n-dimethylpropan-1-amine;prop-2-enamide Chemical compound NC(=O)C=C.CCCN(C)C QQGJWWNPACORPU-UHFFFAOYSA-N 0.000 description 1
- 125000004108 n-butyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- RQAKESSLMFZVMC-UHFFFAOYSA-N n-ethenylacetamide Chemical compound CC(=O)NC=C RQAKESSLMFZVMC-UHFFFAOYSA-N 0.000 description 1
- ZQXSMRAEXCEDJD-UHFFFAOYSA-N n-ethenylformamide Chemical compound C=CNC=O ZQXSMRAEXCEDJD-UHFFFAOYSA-N 0.000 description 1
- UZZYXUGECOQHPU-UHFFFAOYSA-M n-octyl sulfate Chemical compound CCCCCCCCOS([O-])(=O)=O UZZYXUGECOQHPU-UHFFFAOYSA-M 0.000 description 1
- 125000004123 n-propyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 229920002114 octoxynol-9 Polymers 0.000 description 1
- 229940067739 octyl sulfate Drugs 0.000 description 1
- 239000003002 pH adjusting agent Substances 0.000 description 1
- HVAMZGADVCBITI-UHFFFAOYSA-M pent-4-enoate Chemical compound [O-]C(=O)CCC=C HVAMZGADVCBITI-UHFFFAOYSA-M 0.000 description 1
- 229920006267 polyester film Polymers 0.000 description 1
- 230000000379 polymerizing effect Effects 0.000 description 1
- 229920002503 polyoxyethylene-polyoxypropylene Polymers 0.000 description 1
- 229920001451 polypropylene glycol Polymers 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- POSICDHOUBKJKP-UHFFFAOYSA-N prop-2-enoxybenzene Chemical compound C=CCOC1=CC=CC=C1 POSICDHOUBKJKP-UHFFFAOYSA-N 0.000 description 1
- AAYRWMCIKCRHIN-UHFFFAOYSA-N propane-1-sulfonic acid;prop-2-enamide Chemical compound NC(=O)C=C.CCCS(O)(=O)=O AAYRWMCIKCRHIN-UHFFFAOYSA-N 0.000 description 1
- 238000012797 qualification Methods 0.000 description 1
- 238000011002 quantification Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 125000004079 stearyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- IAHFWCOBPZCAEA-UHFFFAOYSA-N succinonitrile Chemical compound N#CCCC#N IAHFWCOBPZCAEA-UHFFFAOYSA-N 0.000 description 1
- 150000005846 sugar alcohols Polymers 0.000 description 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 1
- UZZYXUGECOQHPU-UHFFFAOYSA-N sulfuric acid monooctyl ester Natural products CCCCCCCCOS(O)(=O)=O UZZYXUGECOQHPU-UHFFFAOYSA-N 0.000 description 1
- 239000002352 surface water Substances 0.000 description 1
- 125000000999 tert-butyl group Chemical group [H]C([H])([H])C(*)(C([H])([H])[H])C([H])([H])[H] 0.000 description 1
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
- HGBOYTHUEUWSSQ-UHFFFAOYSA-N valeric aldehyde Natural products CCCCC=O HGBOYTHUEUWSSQ-UHFFFAOYSA-N 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
- KOZCZZVUFDCZGG-UHFFFAOYSA-N vinyl benzoate Chemical group C=COC(=O)C1=CC=CC=C1 KOZCZZVUFDCZGG-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
- G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
- G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
- G02B1/14—Protective coatings, e.g. hard coatings
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
-
- 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
- C08J2329/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal, or ketal radical; Hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Derivatives of such polymer
- C08J2329/02—Homopolymers or copolymers of unsaturated alcohols
- C08J2329/04—Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
Landscapes
- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Materials Engineering (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Manufacture Of Macromolecular Shaped Articles (AREA)
- Polarising Elements (AREA)
Abstract
Provided are a PVA film which can suppress breakage during uniaxial stretching even when the maximum stretching speed is high in uniaxial stretching in the production of an optical film such as a polarizing film, and a polarizing film and a polarizing plate obtained using the PVA film. A polyvinyl alcohol film wherein the amount of bound amorphous component calculated from the relaxation curve obtained by pulse NMR measurement in a 3 mass% boric acid heavy aqueous solution at 50 ℃ is set to (A2) 50℃ The bound amorphous component calculated from the relaxation curve obtained by pulse NMR measurement in a 3 mass% boric acid heavy aqueous solution at 30℃was set as (A2) 30℃ Time, (A2) 50℃ Relative (A2) 30℃ Ratio ((A2) 50℃ /(A2) 30℃ ) 020 to 065.
Description
Technical Field
The present invention relates to a polyvinyl alcohol film, and a polarizing film and a polarizing plate using the same.
Background
A polarizing plate having light transmitting and light blocking functions is the same as a liquid crystal for changing the polarization state of light as a basic constituent of a Liquid Crystal Display (LCD). LCDs are used in a wide range of small devices such as calculators and wristwatches, notebook computers, liquid crystal displays, liquid crystal color projectors, liquid crystal televisions, car navigation systems, cellular phones, and metering devices used indoors and outdoors.
Polarizing plates are generally manufactured by the following operations: a polarizing film is produced by dyeing a polyvinyl alcohol film (hereinafter, sometimes abbreviated as "PVA") and uniaxially stretching the film, and if necessary, further fixing the film with a boron compound or the like, and then a protective film such as a cellulose Triacetate (TAC) film is attached to the surface of the polarizing film. In recent years, the speed of these manufacturing processes has been increased with a view to improving the manufacturing efficiency of optical films such as polarizing films. Accordingly, in the process of producing an optical film such as a polarizing film, there are many cases where a PVA film is stretched at a higher speed than in the prior art.
On the other hand, patent document 1 describes: a polarizing film excellent in shrinkage force and hue is obtained by using a PVA film having a crystal structure obtained by pulse NMR measurement in a specific range. Patent document 2 describes that: a polarizing film excellent in polarizing performance and shrinkage force is obtained by using a PVA film having a crystal structure obtained by pulse NMR measurement in a specific range.
Prior art literature
Patent literature
Patent document 1: japanese patent No. 6408909
Patent document 2: international publication No. 2019/151206
Disclosure of Invention
Problems to be solved by the invention
As described above, in the process of producing an optical film such as a polarizing film, the PVA film is often stretched at a higher speed than before. Accordingly, there is a demand for a PVA film that can suppress breakage during uniaxial stretching even when the maximum stretching speed of uniaxial stretching during manufacturing of an optical film such as a polarizing film is high. However, when a conventional PVA film is uniaxially stretched, if the maximum stretching speed is set to be high, the PVA film cannot follow the deformation speed during stretching, and the stress during stretching increases and breaks, which is a problem. In addition, in the prior art, no study has been made on the relationship between the fracture at the time of uniaxial stretching of such a PVA film and the crystal structure of the PVA film.
Accordingly, an object of the present invention is to provide a PVA film capable of suppressing breakage during uniaxial stretching even when the maximum stretching speed is high in manufacturing an optical film such as a polarizing film, and a polarizing film and a polarizing plate obtained using the PVA film.
Means for solving the problems
The present inventors have conducted intensive studies and as a result, found that: the present invention has been completed by further conducting further research based on the finding that the above-described problems can be achieved by adjusting the ratio of the bound amorphous (bound amorphous) components of the PVA film to a specific range.
Namely, the present invention relates to:
[1]a PVA film having a bound amorphous component calculated from a relaxation curve obtained by pulse NMR measurement in a 3% by mass boric acid heavy aqueous solution at 50℃as (A2) 50℃ The bound amorphous component calculated from the relaxation curve obtained by pulse NMR measurement in a 3 mass% boric acid heavy aqueous solution at 30℃was set as (A2) 30℃ Time, (A2) 50 DEG C relative to (A2) 30℃ Ratio ((A2) 50℃ /(A2) 30℃ ) 0.20 to 0.65;
[2]according toThe aforementioned [1]]The PVA film, wherein (A2) is as described above 50℃ The amount of the crystal component calculated from the relaxation curve obtained by pulse NMR measurement in a 3 mass% boric acid heavy aqueous solution at 50 ℃ was set to 15 or less as (A1) 50℃ Time, (A2) 50℃ Relative (A1) 50℃ Ratio ((A2) 50℃ /(A1) 50℃ ) 0.60 to 1.6;
[3] the PVA film according to any one of the above [1] to [3], having a swelling degree of 170 to 220%;
[4] the PVA film according to the aforementioned [1] or [2], wherein the polymerization degree of PVA contained in the PVA film is from 2,000 to 2,700;
[5] the PVA film according to any one of the above [1] to [4], which is a raw film for producing an optical film;
[6] the PVA film of the aforementioned [5], wherein the optical film is a polarizing film;
[7] a polarizing film produced using the PVA film according to the above [6 ];
[8] A polarizing plate obtained by adhering a protective film to at least one side of the polarizing film according to item [7 ].
Effects of the invention
According to the present invention, it is possible to provide a PVA film capable of suppressing breakage at the time of uniaxial stretching even when the maximum stretching speed of uniaxial stretching is high at the time of producing an optical film such as a polarizing film, and a polarizing film and a polarizing plate produced using such a PVA film.
Drawings
Fig. 1 is a schematic view of a PVA in a PVA film, with crystallized portions, bound amorphous portions, and amorphous portions.
Detailed Description
The present invention will be specifically described below.
< PVA film >
(pulse NMR)
Regarding the PVA film of the present invention, the bound amorphous component amount calculated from the relaxation curve obtained in the pulse NMR measurement performed in a 3 mass% boric acid heavy aqueous solution at 50℃was set to (A2) 50℃ Will be based on 3 mass% boric acid at 30 DEG CThe bound amorphous component amount calculated from the relaxation curve obtained in the pulse NMR measurement performed in the aqueous solution was set to (A2) 30℃ Time, (A2) 50 DEG C relative to (A2) 30℃ Ratio ((A2) 50℃ /(A2) 30℃ ) 0.20 to 0.65. (A2) 50℃ /(A2) 30℃ Preferably 0.20 or more. (A2) 50℃ /(A2) 30℃ Preferably 0.65 or less. If (A2) 50℃ /(A2) 30℃ If the amount is less than 0.20, the PVA film may be dissolved in the stretching tank to be broken. On the other hand, if (A2) 50℃ /(A2) 30℃ If the amount is more than 0.65, the PVA film may be subjected to excessive tension to break. As a pair (A2) 50℃ /(A2) 30℃ The method of setting the value to 0.20 to 0.65 includes: a filtration method of the film-forming raw liquid (for example, the thickness of mesh of a mesh filter); and a method of properly adjusting the surface temperature of a support to which the film-forming stock solution is cast, the temperature of hot air blown to the non-contact surface side of the film-forming stock solution cast on the support, the dew point of the hot air, the drying temperature, the heat treatment temperature, and the like.
PVA film of the present invention (A2) 50℃ Preferably 15 or less, more preferably 13 or less. If (A2) 50℃ If the amount is more than 15, the PVA film tends to be easily broken by applying excessive tension thereto. The amount of the crystalline component calculated from the relaxation curve obtained by pulse NMR measurement in a 3% by mass boric acid heavy aqueous solution at 50℃was set to (A1) 50℃ Time, (A2) 50℃ Relative (A1) 50℃ Ratio ((A2) 50℃ /(A1) 50℃ ) Preferably 0.60 to 1.6. (A2) 50℃ /(A1) 50℃ Preferably 0.60 or more, more preferably 0.80 or more, and still more preferably 1.0 or more. (A2) 50℃ /(A1) 50℃ Preferably 1.6 or less, more preferably 1.4 or less, and still more preferably 1.3 or less. If (A2) 50℃ /(A1) 50℃ If the ratio is less than 0.60, it tends to be difficult to exhibit sufficient optical properties, and if (A2) 50℃ /(A1) 50℃ If the amount is more than 1.6, excessive tension may be applied to the PVA film, which may cause breakage. As a film to be PVA (A2) 50℃ The method is set to 15 or less or will (A2) 50℃ /(A1) 50℃ The method of 0.60 to 1.6 includes: a filtration method of the film-forming raw liquid (for example, the thickness of mesh of a mesh filter); and a method of properly adjusting the surface temperature of a support to which the film-forming stock solution is cast, the temperature of hot air blown to the non-contact surface side of the film-forming stock solution cast on the support, the dew point of the hot air, the drying temperature, the heat treatment temperature, and the like.
PVA film of the present invention (A1) 30℃ Preferably 20 or more, more preferably 25 or more. (A1) 30℃ Preferably 35 or less, more preferably 32 or less.
PVA film of the present invention (A2) 30℃ Preferably 15 or more, more preferably 20 or more. (A2) 30℃ Preferably 24 or less, more preferably 23 or less.
PVA film of the present invention (A3) 30℃ Preferably 40 or more, more preferably 42 or more. (A3) 30℃ Preferably 60 or less, more preferably 55 or less.
PVA film of the present invention (A1) 50℃ Preferably 3 or more, more preferably 5 or more. (A1) 50℃ Preferably 15 or less, more preferably 13 or less.
PVA film of the present invention (A2) 50℃ Preferably 5 or more, more preferably 7 or more. As described above, (A2) 50℃ Preferably 15 or less, more preferably 13 or less.
PVA film of the present invention (A3) 50℃ Preferably 70 or more, more preferably 73 or more. (A3) 50℃ Preferably 95 or less, more preferably 90 or less.
As a PVA film to be used in the present invention (A1) 30℃ 、(A2) 30℃ 、(A3) 30℃ 、(A1) 50℃ 、(A2) 50℃ And (A3) 50℃ The methods in the above range include: a filtration method of the film-forming raw liquid (for example, the thickness of mesh of a mesh filter); and a method of properly adjusting the surface temperature of a support to which the film-forming stock solution is cast, the temperature of hot air blown to the non-contact surface side of the film-forming stock solution cast on the support, the dew point of the hot air, the drying temperature, the heat treatment temperature, and the like.
Here, pulsed NMR andthe general NMR used for the structure determination of an organic compound is different from that used for the structure determination of an organic compound, and can be used for measuring the molecular mobility in a system 1 Analysis method of relaxation time of H nucleus. In addition, in pulse NMR, the presence ratio of each moving component in the system can be determined by utilizing the high quantitative property.
In a pulse NMR measurement apparatus, there is a static magnetic field generated by an electromagnet in the apparatus. In the static magnetic field, the orientation of the nuclear spins of the hydrogen nuclei is oriented in a direction along the static magnetic field. When a pulsed magnetic field is applied in this state, the nuclear spins of the hydrogen nuclei tilt 90 ° from the direction of the static magnetic field (excited state). Thereafter, the orientation of the excited nuclear spins macroscopically returns to the original direction along the static magnetic field. The process of restoring the orientation of nuclear spins from the excited state to the original state is called "T 2 Relaxation ", the time required for this process is referred to as the relaxation time (tau). In the case of relaxation of a single component, the magnetization (y) at time (t) uses the intensity (a) in the excited state, the relaxation time (tau), and constants (y 0, w), and is expressed by the following formula.
y＝y0+a×exp(-1/W×(t/tau) W )
W is called a weibull coefficient, and when w=1, the formula is called Exp type, and when w=2, the formula is Gauss type. In the case of a general polymer, a range of 1.ltoreq.W.ltoreq.2 is used.
At T 2 In the case of relaxation, the hydrogen nuclei undergo energy exchange from the excited state with other hydrogen nuclei while attenuating to the original state. Therefore, when the molecular mobility of the sample is high, the interactions between protons that are close to each other are small, and therefore, energy decay of the whole system is less likely to occur, and the relaxation time becomes long. Accordingly, when the molecular mobility of the sample is low, the relaxation time becomes short. Therefore, if the polymer is crystalline, the relaxation time of the crystalline component becomes short and the relaxation time of the amorphous component becomes long. Furthermore, the boundary portion between the crystalline component and the amorphous component, that is, the bound amorphous component (see fig. 1), exhibits a relaxation time intermediate between the two components.
In general X-ray measurement and the like, only the amount of the crystalline component and the amount of the amorphous component can be measured, but in pulse NMR, measurement of the amount of the crystalline component and the amount of the amorphous component can be performed, and measurement of the amount of the bound amorphous component can also be performed. In particular, in pulse NMR, the presence ratio of each mobile component is determined based on the mobility of the crystalline polymer which is not obtained in the X-ray measurement. The aforementioned presence ratio becomes a value that more accurately reflects various properties sought for the PVA film. Therefore, by using pulse NMR, the properties of the PVA film can be evaluated extremely appropriately.
In the actual crystalline polymer, the above-mentioned crystalline component, the bound amorphous component, and the amorphous component are mixed. Therefore, when the PVA film containing the crystalline polymer is subjected to pulse NMR measurement, the resulting relaxation curve is observed as the sum of a relaxation component derived from a crystalline component having a short relaxation time, a relaxation component derived from an amorphous component having a long relaxation time, and a relaxation component derived from a bound amorphous component having a relaxation time in the middle of both.
In the present invention, a relaxation curve obtained by a linear least square method is fitted in the following equation. When tau1 is the relaxation time of the crystalline component, tau2 is the relaxation time of the bound amorphous component, and tau3 is the relaxation time of the amorphous component, the magnetization (y) of the entire sample at time (t) is expressed by the following expression using the constant y0 and a1, a2, and a3 in the excited state.
y＝y0+a1×exp(-1/W1×(t/tau1) W1 )+a2×exp(-1/W2×(t/tau2) W2 )+a3×exp(-1/W3×(t/tau3) W3 )
As a result of the intensive verification, the following equation was used in which the crystalline component and the bound amorphous component were each gaussian-type relaxation (w1, w2=2) and the amorphous component was fixed to Exp-type relaxation (w3=1) as a equation (fitting function equation) that allows fitting between films produced under each film formation condition with good reproducibility.
y＝y0+a1×exp(-0.5×(t/tau1) 2 )+a2×exp(-0.5×(t/tau2) 2 )+a3×exp(-t/tau3)
In the present invention, A1, A2, A3 and tau1, tau2, tau3, y0 derived from the above formula are obtained, and the ratio (%) of each component to the total of A1, A2, and A3 (a1+a2+a3) is defined as the crystalline component amount (A1), the bound amorphous component amount (A2), and the amorphous component amount (A3), respectively. For example, the value of the bound amorphous component amount (A2) is represented by a2/(a1+a2+a3) ×100.
(degree of swelling)
The swelling degree of the PVA film of the present invention is preferably 170% or more. The swelling degree of the PVA film is preferably 220% or less. If the swelling degree is less than 170%, uneven swelling tends to occur, and the dyeing tends to be uneven. If the swelling degree is more than 220%, wrinkles tend to occur in the process, which is not preferable. Examples of the method for adjusting the swelling degree of the PVA film to these ranges include a method for appropriately adjusting the heat treatment temperature, the time of contact with the heat treatment roller, and the like.
The swelling degree is an index showing the water retention ability of the PVA film when immersed in water, and can be determined as a percentage by dividing the mass of the PVA film after being immersed in water at 30℃for 30 minutes by the mass of the PVA film after being dried at 105℃for 16 hours.
(PVA)
Examples of the PVA included in the PVA film of the present invention include PVA obtained by saponifying a polyvinyl ester obtained by polymerizing one or more of vinyl esters such as vinyl acetate, vinyl formate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl tertiary carboxylate, vinyl laurate, vinyl stearate, vinyl benzoate, and isopropenyl acetate. Among the vinyl esters, vinyl acetate is preferred from the viewpoints of ease of production, ease of acquisition, cost and the like of PVA.
The polyvinyl ester is preferably a polyvinyl ester obtained by using only 1 or 2 or more kinds of vinyl esters as monomers, more preferably a polyvinyl ester obtained by using only 1 kind of vinyl esters as monomers, and if the effect of the present invention is not impaired, it may be a copolymer of 1 or 2 or more kinds of vinyl esters and other monomers copolymerizable therewith.
Examples of the other monomer copolymerizable with the vinyl ester include alpha-olefins having 2 to 30 carbon atoms such as ethylene, propylene, 1-butene and isobutylene; (meth) acrylic acid or a salt thereof; (meth) acrylic esters such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (meth) acrylate, and the like; (meth) acrylamide derivatives such as (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-dimethyl (meth) acrylamide, diacetone (meth) acrylamide, (meth) acrylamide propane sulfonic acid or a salt thereof, (meth) acrylamide propyldimethylamine or a salt thereof, and N-hydroxymethyl (meth) acrylamide or a derivative thereof; n-vinylamides such as N-vinylformamide, N-vinylacetamide and N-vinylpyrrolidone; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether and stearyl vinyl ether; ethylene cyanide such as (meth) acrylonitrile; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl fluoride, and vinylidene fluoride; allyl compounds such as allyl acetate and allyl chloride; maleic acid or a salt, ester or anhydride thereof; itaconic acid or a salt, ester or anhydride thereof; vinyl silyl compounds such as vinyl trimethoxy silane; unsaturated sulfonic acids, and the like. The polyvinyl ester may have a structural unit derived from 1 or 2 or more monomers among the other monomers.
The proportion of the structural units derived from other monomers in the polyvinyl ester is preferably 15 mol% or less, more preferably 10 mol% or less, and still more preferably 5 mol% or less, based on the number of moles of all the structural units constituting the polyvinyl ester.
As the other monomer, ethylene is preferable. The polarization performance of the resulting polarizing film is sometimes improved by copolymerizing ethylene. The content of the ethylene unit in the PVA is preferably 0.5 mol% or more, more preferably 1 mol% or more, and still more preferably 1.5 mol% or more. The content of the ethylene unit is preferably 8 mol% or less, more preferably 5 mol% or less.
In the case where other monomers are monomers such as (meth) acrylic acid, unsaturated sulfonic acid, and the like, which are likely to promote water solubility of the resulting PVA, the proportion of structural units derived from these monomers in the polyvinyl ester is preferably 5 mol% or less, more preferably 3 mol% or less, based on the number of moles of all structural units constituting the polyvinyl ester, in order to prevent dissolution of PVA when the resulting PVA film is used as a raw material film for producing a polarizing film, and the like.
If the effect of the present invention is not impaired, PVA may be modified with 1 or 2 or more graft copolymerizable monomers. Examples of the graft copolymerizable monomer include unsaturated carboxylic acids or derivatives thereof; unsaturated sulfonic acid or derivatives thereof; alpha-olefins having 2 to 30 carbon atoms, and the like. The proportion of the structural unit derived from the graft copolymerizable monomer in the PVA is preferably 5 mol% or less based on the number of moles of all the structural units constituting the PVA.
Some of the hydroxyl groups in the PVA may be crosslinked or uncrosslinked. In addition, a part of hydroxyl groups in the PVA may be reacted with an aldehyde compound such as acetaldehyde or butyraldehyde to form an acetal structure, or may not be reacted with these compounds to form an acetal structure.
The polymerization degree of PVA is preferably 2000 or more, more preferably 2200 or more, and still more preferably 2400 or more. In the case where the polymerization degree is less than 2000, the durability of the resulting polarizing film tends to be lowered. The polymerization degree of PVA is preferably 2700 or less, more preferably 2650 or less, and still more preferably 2600 or less. When the polymerization degree exceeds 2700, the production cost increases and the process qualification at the time of film formation tends to be deteriorated. The polymerization degree of PVA referred to in the present specification means an average polymerization degree measured in accordance with JIS K6726-1994.
The saponification degree of PVA is preferably 98 mol% or more, more preferably 98.5 mol% or more, and still more preferably 99 mol% or more from the viewpoint of water resistance of the polarizing film. If the saponification degree is less than 98 mol%, the water resistance of the resulting polarizing film tends to be poor. The saponification degree of PVA in the present specification means: the PVA has a proportion (mol%) of the total mole number of the structural unit (typically, vinyl ester unit) capable of being converted into a vinyl alcohol unit by saponification and the vinyl alcohol unit. The saponification degree can be measured as described in JISK 6726-1994.
(plasticizer)
The PVA film of the present invention preferably contains a plasticizer. Examples of the plasticizer include polyhydric alcohols such as ethylene glycol, glycerin, propylene glycol, diethylene glycol, diglycerin, triethylene glycol, tetraethylene glycol, and trimethylolpropane, and the PVA film of the present invention may contain 1 or 2 or more of these plasticizers. Among these, glycerin is preferred from the viewpoint of improving the stretchability.
The plasticizer content in the PVA film of the present invention is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and still more preferably 5 parts by mass or more, per 100 parts by mass of PVA. By setting the content of the plasticizer to 1 part by mass or more, the stretchability of the PVA film can be further improved. On the other hand, the content of the plasticizer is preferably 20 parts by mass or less, more preferably 17 parts by mass or less, and still more preferably 15 parts by mass or less, based on 100 parts by mass of PVA. When the plasticizer content is 20 parts by mass or less, the PVA film is prevented from being too soft and the handleability is prevented from being lowered.
(surfactant)
The PVA film of the present invention preferably comprises a surfactant. The film forming property of the PVA film is improved by producing the PVA film by using a film forming stock solution containing a surfactant. As a result, the PVA film can be easily peeled from the metal roll or belt used for film formation while suppressing occurrence of thickness unevenness of the PVA film. In the case of producing a PVA film from a film-forming stock solution containing a surfactant, the resulting PVA film contains a surfactant.
The type of the surfactant is not particularly limited, but from the viewpoint of peelability of the PVA film from the metal roll or the belt, and the like, an anionic surfactant and a nonionic surfactant are preferable.
The anionic surfactant is preferably a carboxylic acid type such as potassium laurate; sulfate esters such as polyoxyethylene lauryl ether sulfate and octyl sulfate; sulfonic acid type such as dodecylbenzenesulfonate.
As the nonionic surfactant, for example, alkyl ether type surfactants such as polyoxyethylene oleyl ether are suitable; alkylphenyl ethers such as polyoxyethylene octylphenyl ether; alkyl esters such as polyoxyethylene laurate; alkylamines such as polyoxyethylene lauryl amino ether; alkylamide type such as polyoxyethylene lauramide; polypropylene glycol ethers such as polyoxyethylene polyoxypropylene ether; alkanolamide type such as lauric acid diethanolamide and oleic acid diethanolamide; and allylphenyl ethers such as polyoxyalkylene allylphenyl ether.
These surfactants may be used alone or in combination of 1 or more than 2.
The content of the surfactant in the PVA film of the present invention is preferably 0.01 part by mass or more, more preferably 0.02 part by mass or more, and still more preferably 0.05 part by mass or more, based on 100 parts by mass of PVA. When the content of the surfactant is 0.01 parts by mass or more, the film forming property and peeling property of the PVA film are further improved. On the other hand, the content of the surfactant in the PVA film is preferably 0.5 parts by mass or less, more preferably 0.3 parts by mass or less, and still more preferably 0.2 parts by mass or less, based on 100 parts by mass of PVA. When the content of the surfactant is 0.5 parts by mass or less, bleeding of the surfactant to the surface of the PVA film and blocking are easily suppressed, and deterioration of handleability is easily suppressed.
(other Components)
The PVA film of the present invention may further contain, if necessary, an antioxidant, an antifreeze agent, a pH adjuster, a masking agent, an anti-coloring agent, an oil agent, a surfactant described later, and the like.
(shape, etc.)
The shape of the PVA film of the present invention is not particularly limited, but is preferably a long film. This enables a more uniform PVA film to be produced continuously and easily, and can be used continuously even when a polarizing film is produced using the PVA film. The length (length in the longitudinal direction) of the long film is not particularly limited, and may be appropriately set according to the application or the like, and may be set in a range of 5 to 30,000m, for example.
The width of the PVA film of the present invention is not particularly limited, and may be appropriately set according to the use of the PVA film, polarizing film produced therefrom, and the like. In recent years, from the viewpoint of increasing the screen size of liquid crystal televisions and liquid crystal displays, it is preferable to use a PVA film having a width of 3m or more, more preferably 4m or more, in advance for these applications. On the other hand, if the width of the PVA film is too wide, it is easy to make uniaxial stretching itself difficult to uniformly proceed in the case of producing a polarizing film by using a device which has been put into practical use, and therefore, the width of the PVA film is preferably 7m or less.
The thickness of the PVA film of the present invention is desirably 30 to 60. Mu.m. If the thickness is less than 30 μm, the processability during stretching is deteriorated, and if it is 60 μm or more, it is not preferable as a polarizing plate for a thin display.
< method for producing PVA film >
In the present invention, the method for producing the PVA film is not particularly limited, and the following method can be employed: a method of forming a film using a film-forming raw liquid obtained by adding a solvent, an additive, or the like to PVA and homogenizing the same, a film-forming method using a casting film method, a wet film-forming method (spraying out a poor solvent), a dry-wet film-forming method, a gel film-forming method (a method of obtaining a PVA film by once cooling and gelling the film-forming raw liquid and then extracting and removing the solvent), or a combination thereof; a melt extrusion film-forming method of forming a film by obtaining the film-forming stock solution by using an extruder or the like and extruding the film-forming stock solution from a T die or the like; any method such as inflation molding. Among these, the casting film forming method and the melt extrusion film forming method are preferable because they can obtain a homogeneous film with good productivity. Hereinafter, a casting film forming method or a melt extrusion film forming method of a PVA film will be described.
In the case of producing a PVA film by a casting film-forming method or a melt extrusion film-forming method, the film-forming stock solution is cast into a film on a support such as a metal roll or a metal belt, and the film is formed by heating to remove a solvent, thereby solidifying the film-forming stock solution. The cured film is peeled from the support, dried by a drying roll, a drying furnace, or the like as necessary, and further heat-treated and wound up as necessary, whereby a long PVA film in a roll form can be obtained.
The volatile fraction (water content) of the film-forming stock solution varies depending on the film-forming method, film-forming conditions, and the like. If the evaporation fraction of the film-forming stock solution is too low, the following tends to occur: the viscosity of the film-forming stock solution becomes too high, and it is difficult to filter and defoam the film-forming stock solution, and it is difficult to produce a PVA film having few impurities and defects. The volatile fraction is preferably 50% by mass or more, more preferably 55% by mass or more, and still more preferably 60% by mass or more. On the other hand, if the evaporation rate of the film-forming stock solution is too high, the following tends to occur: the concentration of the film-forming stock solution becomes too low, and it is difficult to industrially produce PVA films. The volatile fraction is preferably 95% by mass or less, more preferably 90% by mass or less, and still more preferably 85% by mass or less.
Here, the term "volatile fraction of the film forming stock solution" in the present invention refers to a volatile fraction obtained by the following formula.
Volatile fraction (mass%) of film-forming stock solution = { (Wa-Wb)/Wa } ×100
(wherein Wa represents the mass (g) of the film-forming stock solution; wb represents the mass (g) of the film-forming stock solution obtained by drying Wa (g) in an electrothermal drier at 105 ℃ for 16 hours).
The method for adjusting the film-forming stock solution is not particularly limited, and examples thereof include: for example, a method of dissolving PVA and additives such as plasticizers and surfactants in a dissolution tank or the like; and a method in which, when PVA in a water-containing state is melt-kneaded using a single-screw extruder or a twin-screw extruder, the PVA is melt-kneaded together with a plasticizer, a surfactant, or the like.
Examples of the liquid medium used for preparing the film-forming stock solution include water, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, ethylene glycol, glycerin, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, trimethylolpropane, ethylenediamine, diethylenetriamine, and the like, and one or more of these may be used. Among them, water is suitable from the viewpoint of environmental burden and recyclability.
When a PVA film is produced by a casting film-forming method or a melt extrusion film-forming method, when a film-forming stock solution is cast into a film on a support such as a metal roll or a metal belt, it is preferable to filter the film-forming stock solution in advance. The filtration method of the membrane-forming stock solution is preferably filtration by a mesh filter. The mesh size of the mesh filter used is preferably 180 mesh or more, more preferably 200 mesh or more. The mesh size of the mesh filter used is preferably 330 mesh or less, more preferably 320 mesh or less. If the mesh size is larger than 180 mesh, undissolved substances in the stock solution tend to remain in the film as impurities. On the other hand, if the mesh size is smaller than 330 mesh, the crystallization process of the PVA film during drying is affected, and the ratio of the amount of bound amorphous component of the PVA film (A2) 50℃ /(A2) 30℃ And do not tend to satisfy the above range.
The surface temperature of the support to be cast into the film stock solution is preferably 85 ℃ or higher, more preferably 88 ℃ or higher, and still more preferably 90 ℃ or higher. The surface temperature of the support to be cast into the film stock solution is preferably 100 ℃ or less, more preferably 99 ℃ or less, and still more preferably 98 ℃ or less. When the surface temperature of the support is not in the range of 85 to 100 ℃, there is a ratio (A2) of the amount of bound amorphous component of the PVA film 50℃ /(A2) 30℃ It is difficult to satisfy the above-described range.
The drying rate can be adjusted by uniformly blowing hot air having a wind speed of 1 to 10 m/sec to all regions of the PVA film on the surface side not in contact with the support while heating a film-forming stock solution (hereinafter, abbreviated as PVA film in some cases) cast on the support. The temperature of the hot air blown against the non-contact surface side is preferably 80 ℃ or higher, more preferably 85 ℃ or higher, and still more preferably 88 ℃ or higher. The temperature of the hot air blown against the non-contact surface side is preferably 110 ℃ or lower, more preferably 105 ℃ or lower, and still more preferably 99 ℃ or lower. If the hot air temperature exceeds 110 ℃, the following tends to occur: PVA crystals in PVA film overgrow, ratio of bound amorphous component amount of PVA film (A2) 50℃ /(A2) 30℃ It is difficult to satisfy the above range. On the other hand, if the hot air temperature is lower than 80 ℃, the production process speed of the PVA film tends to be low.
The dew point of hot air blown to the non-contact surface side is also important from the viewpoint of controlling the crystallinity of the PVA film. The dew point of hot air blown to the non-contact surface side is preferably 10 ℃ or higher, more preferably 14 ℃ or higher. The dew point of hot air blown to the non-contact surface side is preferably 20 ℃ or lower, and more preferably 18 ℃ or lower. If the dew point is higher than 20 ℃, the following tends to occur: crystal overgrowth of PVA film, ratio of bound amorphous component amount of PVA film (A2) 50℃ /(A2) 30℃ It is difficult to satisfy the above range. If the dew point is lower than 10 ℃, the film surface quality may be impaired by dew condensation in the cooling portion around the manufacturing apparatus.
The PVA film is preferably dried to a volatile fraction of 5 to 50 mass% on a support, then peeled off, and further dried as needed. The drying method is not particularly limited, and a method of bringing the dried product into contact with a drying furnace or a drying roll is exemplified. In the case of drying the film by a plurality of drying rolls, it is preferable to make the surfaces of the film uniform by alternately contacting the drying rolls with one surface and the other surface of the film. The number of the drying rolls is preferably 3 or more, more preferably 4 or more, and still more preferably 5 or more. The number of drying rolls is preferably 30 or less. The temperature of the drying furnace or the average temperature of the drying roller (average value of the surface temperature of the drying roller) is preferably 110 ℃ or less, more preferably 100 ℃ or less, still more preferably 90 ℃ or less, and still more preferably 85 ℃ or less. If the temperature of the drying furnace or the average temperature of the drying roller is too high, the following tends to occur: the crystal growth of PVA film is aggravated, the ratio of the amount of bound amorphous component of PVA film (A2) 50℃ /(A2) 30℃ It is difficult to satisfy the above range. On the other hand, the temperature of the drying oven or the average temperature of the drying roller is preferably 40 ℃ or higher, more preferably 45 ℃ or higher, and still more preferably 50 ℃ or higher. If the temperature of the drying furnace or the average temperature of the drying roller is too low, the following tends to occur: the crystal growth of the PVA film became insufficient, the ratio of the amount of bound amorphous components of the PVA film (A2) 50℃ /(A2) 30℃ It is difficult to satisfy the above-mentioned rangeAnd (5) enclosing.
The dried PVA film may be further heat treated as needed. The strength, swelling degree, complex refractive index, and the like of the PVA film can be adjusted by performing the heat treatment. The surface temperature of the heat treatment roller for performing the heat treatment is preferably 60 ℃ or higher. The surface temperature of the heat treatment roller is preferably 135 ℃ or less, more preferably 130 ℃ or less. If the surface temperature of the heat treatment roller is too high, the following tends to occur: the amount of heat applied becomes excessive, the size of the platelets in the PVA film becomes large, and the ratio of the amount of bound amorphous components of the PVA film (A2) 50℃ /(A2) 30℃ It is difficult to satisfy the above range. The time for which the PVA film is contacted with the heat treating roller is preferably 1 second or more, more preferably 2 seconds or more. The time of contact with the heat treatment roller is preferably 60 seconds or less, more preferably 30 seconds or less.
The PVA film thus produced is further subjected to a humidity conditioning treatment, cutting of both ends (edges) of the film, and the like as needed, and wound up in a roll form on a paper sheet or a cylindrical core, and then subjected to a humidity-proof package to form a product.
The volatile fraction of the PVA film finally obtained by the above-described series of processes is not necessarily limited. The volatile fraction of the PVA film is preferably 1 mass% or more, more preferably 2 mass% or more. The volatile fraction of the PVA film is preferably 5 mass% or less, more preferably 4 mass% or less.
< method for producing optical film >
The PVA film of the present invention is used as a raw film in the production of an optical film. Examples of the optical film include a polarizing film, a viewing angle improving film, a retardation film, and a brightness enhancing film, and the PVA film of the present invention can be suitably used as a raw material film in producing a polarizing film. Hereinafter, a method for producing a polarizing film will be specifically described as an example of a method for producing an optical film.
The polarizing film can be generally produced by using a PVA film as a raw film and subjecting the film to a swelling step, a dyeing step, a crosslinking step, a stretching step, a fixing step, and other treatment steps. Specific examples of the treatment liquid used in each step include a swelling treatment liquid used in a swelling treatment, a dyeing treatment liquid (dyeing liquid) used in a dyeing treatment, a crosslinking treatment liquid used in a crosslinking treatment, a stretching treatment liquid used in a stretching treatment, a fixing treatment liquid used in a fixing treatment, a cleaning treatment liquid (cleaning liquid) used in a cleaning treatment, and the like.
Each processing step that can be employed in the manufacturing method for manufacturing a polarizing film is described below. In the method for manufacturing a polarizing film, 1 or 2 or more of the following treatments may be omitted, the same treatment may be performed a plurality of times, or other treatments may be performed simultaneously.
(washing treatment before swelling treatment)
The PVA film is preferably subjected to a washing treatment before the swelling treatment. By such a washing treatment before the swelling treatment, the anti-blocking agent or the like adhering to the PVA film can be removed, and contamination of each treatment liquid in the production process of the polarizing film by the anti-blocking agent or the like can be prevented. The cleaning treatment is preferably performed by immersing the PVA film in a cleaning treatment liquid, or by blowing a cleaning treatment liquid onto the PVA film. As the cleaning treatment liquid, for example, water can be used. The temperature of the cleaning treatment liquid is preferably in the range of 20 to 40 ℃. The removal of the anti-blocking agent or the like adhering to the PVA film is easily performed by setting the temperature of the cleaning treatment liquid to 20 ℃ or higher. In addition, by setting the temperature of the cleaning treatment liquid to 40 ℃ or lower, dissolution of a part of the surface of the PVA film, sticking of films to each other, and degradation of the handleability can be prevented. The temperature of the cleaning liquid is more preferably 22℃or higher, still more preferably 24℃or higher, and particularly preferably 26℃or higher. The temperature of the cleaning liquid is more preferably 38 ℃ or lower, still more preferably 36 ℃ or lower, and particularly preferably 34 ℃ or lower.
(swelling treatment)
The swelling treatment may be performed by immersing the PVA film in a swelling treatment liquid such as water. The temperature of the swelling treatment liquid is preferably 20℃or higher, more preferably 22℃or higher, and still more preferably 24℃or higher. The temperature of the swelling treatment liquid is preferably 40 ℃ or lower, more preferably 38 ℃ or lower, and further preferably 36 ℃ or lower. The time for immersing in the swelling treatment liquid is, for example, preferably 0.1 minutes or more, more preferably 0.5 minutes or more. The time for immersing in the swelling treatment liquid is, for example, preferably 5 minutes or less, more preferably 3 minutes or less. The water used as the swelling treatment liquid is not limited to pure water, and may be an aqueous solution in which various components such as a boron-containing compound are dissolved, or may be a mixture of water and an aqueous medium. The type of the boron-containing compound is not particularly limited, and boric acid or borax is preferable from the viewpoint of handling properties. When the swelling treatment liquid contains a boron-containing compound, the concentration of the boron-containing compound is preferably 6 mass% or less from the viewpoint of improving the stretchability of the PVA film.
(dyeing treatment)
The dyeing treatment may be performed using an iodine-based dye as a dichroic dye, and the dyeing timing may be any stage before, during, or after the stretching treatment. The dyeing treatment is preferably performed by immersing the PVA film in a dyeing treatment liquid using a solution (suitably an aqueous solution) containing iodine-potassium iodide as the dyeing treatment liquid. The concentration of iodine in the dyeing treatment liquid is preferably in the range of 0.005 to 0.2 mass%, and potassium iodide/iodine (mass) is preferably in the range of 20 to 100. The temperature of the dyeing treatment liquid is preferably 20 ℃ or higher, more preferably 25 ℃ or higher. The temperature of the dyeing treatment liquid is preferably 50 ℃ or lower, more preferably 40 ℃ or lower. The dyeing liquid may contain a boron-containing compound such as boric acid as a crosslinking agent. If a dichroic dye is previously contained in the PVA film used as the raw material film, the dyeing treatment can be omitted. In addition, a boron-containing compound such as boric acid and borax may be contained in advance in the PVA film used as the raw material film.
(crosslinking treatment)
In the production of the polarizing film, for the purpose of firmly adsorbing the dichroic dye to the PVA film or the like, it is preferable to perform a crosslinking treatment after the dyeing treatment. The crosslinking treatment may be performed by using a solution (suitably an aqueous solution) containing a crosslinking agent as the crosslinking treatment liquid, and immersing the PVA film in the crosslinking treatment liquid. As the crosslinking agent, 1 or 2 or more kinds of boron-containing compounds such as boric acid and borax can be used. If the concentration of the crosslinking agent in the crosslinking treatment liquid is too high, the following tends to occur: if the crosslinking reaction is excessively performed, it is difficult to sufficiently stretch the film after the subsequent stretching treatment, and if the crosslinking reaction is excessively performed, the effect of the crosslinking treatment tends to be lowered. The concentration of the crosslinking agent in the crosslinking treatment liquid is preferably 1% by mass or more, more preferably 1.5% by mass or more, and still more preferably 2% by mass or more. The concentration of the crosslinking agent in the crosslinking treatment liquid is preferably 6% by mass or less, more preferably 5.5% by mass or less, and still more preferably 5% by mass or less.
In order to inhibit the dichroic dye from eluting from the PVA film after the dyeing treatment, the crosslinking treatment liquid may contain an iodine-containing compound such as potassium iodide. If the concentration of the iodine-containing compound in the crosslinking treatment liquid is too high, the heat resistance of the resulting polarizing film tends to be lowered, although the reason is not clear. If the amount is too small, the effect of suppressing elution of the dichroic dye tends to be lowered. The concentration of the iodine-containing compound in the crosslinking treatment liquid is preferably 1% by mass or more, more preferably 1.5% by mass or more, and still more preferably 2% by mass or more. The concentration of the iodine-containing compound in the crosslinking treatment liquid is preferably 6% by mass or less, more preferably 5.5% by mass or less, and still more preferably 5% by mass or less.
If the temperature of the crosslinking treatment liquid is too high, the polarizing film obtained by eluting the dichroic dye tends to be likely to suffer from uneven dyeing, and if it is too low, the effect of the crosslinking treatment may be reduced. The temperature of the crosslinking treatment liquid is preferably 20℃or higher, more preferably 22℃or higher, and still more preferably 25℃or higher. The temperature of the crosslinking treatment liquid is preferably 45℃or lower, more preferably 40℃or lower, and still more preferably 35℃or lower.
In each of the above-described treatments, the PVA film may be stretched differently from the stretching treatment described later. By performing such stretching (pre-stretching), wrinkles can be prevented from occurring on the surface of the PVA film. From the viewpoint of polarization performance of the obtained polarizing film, etc., the total stretching magnification of the pre-stretching (magnification obtained by multiplying the stretching magnification in each process) is preferably 4 times or less, more preferably 3.5 times or less, depending on the original length of the PVA film of the raw material before stretching. From the viewpoint of polarization performance of the obtained polarizing film, the total stretching magnification of the pre-stretching is preferably 1.5 times or more depending on the original length of the PVA film of the raw material before stretching. The stretching ratio in the swelling treatment is preferably 1.1 times or more, more preferably 1.2 times or more, and still more preferably 1.4 times or more. The stretching ratio in the swelling treatment is preferably 3 times or less, more preferably 2.5 times or less, and still more preferably 2.3 times or less. The stretch ratio in the dyeing treatment is preferably 2 times or less, more preferably 1.8 times or less, and still more preferably 1.5 times or less. The stretch ratio in the dyeing treatment is preferably 1.1 times or more. The stretching ratio in the crosslinking treatment is preferably 2 times or less, more preferably 1.5 times or less, and still more preferably 1.3 times or less. The stretching ratio in the crosslinking treatment is preferably 1.05 times or more.
(stretching treatment)
The stretching treatment may be performed by either a wet stretching method or a dry stretching method. In the case of the wet stretching method, a solution (suitably an aqueous solution) containing a boron-containing compound such as boric acid may be used as the stretching treatment liquid, and the stretching treatment liquid may be used, or the dyeing treatment liquid or a fixing treatment liquid described later may be used. In the case of the dry stretching method, the PVA film after water absorption may be used and may be used in air. Among these, the wet stretching method is preferable, and the uniaxial stretching is more preferable in an aqueous solution containing boric acid. When the stretching treatment liquid contains a boron-containing compound, the concentration of the boron-containing compound in the stretching treatment liquid is preferably 1.5 mass% or more, more preferably 2.0 mass% or more, and still more preferably 2.5 mass% or more, from the viewpoint of improving the stretchability of the PVA film. When the stretching treatment liquid contains a boron-containing compound, the concentration of the boron-containing compound in the stretching treatment liquid is preferably 7 mass% or less, more preferably 6.5 mass% or less, and further preferably 6 mass% or less, from the viewpoint of improving the stretchability of the PVA film.
The stretching treatment liquid preferably contains an iodine-containing compound such as potassium iodide. If the concentration of the iodine-containing compound in the stretching treatment liquid is too high, the resulting polarizing film tends to be significantly bluish in hue, and if it is too low, the heat resistance of the resulting polarizing film tends to be lowered although the reason is not clear. The concentration of the iodine-containing compound in the stretching treatment liquid is preferably 2% by mass or more, more preferably 2.5% by mass or more, and still more preferably 3% by mass or more. The concentration of the iodine-containing compound in the stretching treatment liquid is preferably 8 mass% or less, more preferably 7.5 mass% or less, and still more preferably 7 mass% or less.
If the temperature of the stretching treatment liquid is too high, the PVA film tends to be dissolved and softened and easily broken, and if it is too low, the stretchability tends to be lowered. The temperature of the stretching treatment liquid is preferably 50℃or higher, more preferably 52.5℃or higher, and still more preferably 55℃or higher. The temperature of the stretching treatment liquid is preferably 70 ℃ or lower, more preferably 67.5 ℃ or lower, and still more preferably 65 ℃ or lower. The preferable range of the stretching temperature in the case of stretching by the dry stretching method is also as described above.
The stretching ratio in the stretching treatment is preferably 1.2 times or more, more preferably 1.5 times or more, and still more preferably 2 times or more, from the viewpoint that a polarizing film or the like having more excellent polarizing performance can be obtained at a high time. Further, from the viewpoint of the polarizing performance of the resulting polarizing film, the total stretching ratio (ratio obtained by multiplying the stretching ratio in each step) including the stretching ratio of the above-described pre-stretching is preferably 5.5 times or more, more preferably 5.7 times or more, still more preferably 5.9 times or more, depending on the original length of the PVA film of the raw material before stretching. The upper limit of the stretching ratio is not particularly limited, and if it is too high, stretching fracture is likely to occur, so that it is preferably 8 times or less.
The method of stretching by uniaxial stretching is not particularly limited, and uniaxial stretching in the longitudinal direction and transverse uniaxial stretching in the width direction may be employed. In the case of manufacturing a polarizing film, uniaxial stretching in the longitudinal direction is preferable from the viewpoint of obtaining a polarizing film excellent in polarization performance. The uniaxial stretching in the longitudinal direction can be performed by using a stretching device having a plurality of rolls parallel to each other and changing the peripheral speed between the rolls.
In the present invention, the maximum stretching speed (%/min) in the case of stretching treatment by uniaxial stretching is not particularly limited, but is preferably 200%/min or more, more preferably 300%/min or more, and still more preferably 400%/min or more. Here, the maximum stretching speed means: when stretching a PVA film in two or more stages using 3 or more rolls having different peripheral speeds, the stretching speed is the fastest in the stages. When the stretching treatment of the PVA film is performed in 1 stage, not in two or more stages, the stretching speed in the stage becomes the maximum stretching speed. The stretching speed means: an increase in the length of the PVA film increased by stretching relative to the length of the PVA film before stretching per unit time. For example, a stretch speed of 100%/min means: the PVA film was deformed from the length before stretching to a speed of 2 times the length at 1 minute. The larger the maximum stretching speed is, the more the stretching treatment (uniaxial stretching) of the PVA film can be performed at a high speed, and as a result, the productivity of the polarizing film is improved, which is preferable. On the other hand, if the maximum stretching speed becomes too high, excessive tension may be applied locally to the PVA film during the stretching treatment (uniaxial stretching) of the PVA film, and stretch breaking may easily occur. From this point of view, the maximum stretching speed is preferably not more than 900%/min.
(fixing treatment)
In manufacturing the polarizing film, in order to firmly adsorb the dichroic dye to the PVA film, it is preferable to perform a fixing treatment. The fixing treatment may be performed by using a solution (suitably an aqueous solution) containing 1 or 2 or more kinds of boron-containing compounds such as boric acid and borax as the fixing treatment liquid, and immersing the PVA film (suitably a PVA film after the stretching treatment) in the fixing treatment liquid. The fixing treatment liquid may contain an iodine-containing compound or a metal compound, if necessary. The concentration of the boron-containing compound in the fixation treatment liquid is preferably 2% by mass or more, more preferably 3% by mass or more. The concentration of the boron-containing compound in the fixation treatment liquid is preferably 15 mass% or less, more preferably 10 mass% or less. The temperature of the fixing treatment liquid is preferably 15℃or higher, more preferably 25℃or higher. The temperature of the fixing treatment liquid is preferably 60℃or lower, more preferably 40℃or lower.
(washing treatment after dyeing treatment)
After the dyeing treatment, the PVA film after the stretching treatment is preferably subjected to a cleaning treatment. The cleaning treatment may be performed by immersing the PVA film in a cleaning treatment liquid, or by blowing a cleaning treatment liquid onto the PVA film. As the cleaning treatment liquid, for example, water can be used. The water is not limited to pure water, and may contain an iodine-containing compound such as potassium iodide. In this case, the concentration of the boron-containing compound is preferably 2.0 mass% or less.
The temperature of the cleaning treatment liquid is preferably in the range of 5 to 40 ℃. By setting the temperature to 5 ℃ or higher, breakage of the PVA film due to freezing of moisture can be suppressed. In addition, the optical characteristics of the resulting polarizing film are improved by setting the temperature to 40 ℃ or lower. The temperature of the cleaning liquid is more preferably 7℃or higher, and still more preferably 10℃or higher. The temperature of the cleaning liquid is more preferably 38 ℃ or lower, and still more preferably 35 ℃ or lower.
Specific methods for producing the polarizing film include a method of dyeing a PVA film, stretching the PVA film, and crosslinking and/or fixing the PVA film. Preferable examples include a method in which a PVA film is sequentially subjected to a swelling treatment, a dyeing treatment, a crosslinking treatment, a stretching treatment (in particular, a uniaxial stretching treatment), and a washing treatment. The stretching treatment may be performed in any treatment step preceding the above step, or may be performed in two or more stages.
The PVA film subjected to each of the treatments described above is subjected to a drying treatment, whereby a polarizing film can be obtained. The method of the drying treatment is not particularly limited, and examples thereof include a contact method in which the film is brought into contact with a heating roller, a method in which the film is dried in a hot air dryer, a float method in which the film is dried by hot air while being floated, and the like.
< polarizing film, polarizing plate >
The polarizing film of the present invention is suitably used as a polarizing plate by adhering an optically transparent protective film having mechanical strength to both sides or one side thereof. As the protective film, a cellulose Triacetate (TAC) film, a Cellulose Acetate Butyrate (CAB) film, an acrylic film, a polyester film, or the like can be used. Examples of the adhesive used for the adhesion include PVA-based adhesives and urethane-based adhesives, and among them, PVA-based adhesives are preferable.
The polarizing plate obtained in the above-described manner can be used as a component of an LCD by being attached to a glass substrate after an acrylic adhesive or the like is applied. The retardation film, the viewing angle improving film, the brightness enhancing film, and the like may be bonded together.
Examples
The present invention will be specifically described with reference to the following examples, but the present invention is not limited to these examples at all. The following examples, comparative examples and reference examples show the respective measurement methods used.
< quantification of crystalline component amount (A1), bound amorphous component amount (A2) and amorphous component amount (A3) >)
Samples (100 mg) obtained from PVA films obtained in examples and comparative examples below were cut into a size of about 5mm by 5mm, and then stored in NMR tubes having an inner diameter of 10 mm. Then, a3 mass% boric acid heavy aqueous solution was prepared as a measurement solvent, and 500. Mu.L of the measurement solvent was supplied into the NMR tube containing the sample. Thereafter, the sample was incubated at 30℃or 50℃for 30 minutes and then subjected to pulse NMR measurement under the following conditions to obtain a relaxation curve.
(pulse NMR measurement conditions)
Measurement device: NMRAnalyzermq20the minispec
(manufactured by BRUKER Co., ltd.)
Pulse series: solid-Eco process
Pulse amplitude: 7.22 mu s
Pulse repetition time: 1s
Dummy Shoot：0
Pulsed Atten：0dB
Cumulative number of times: 300 times
Measuring temperature: 30 ℃ or 50 DEG C
Gain: 70-110 dB (according to the observation intensity of the sample)
The obtained relaxation is subjected to the methodThe relaxation curves were fitted to determine the amount of crystalline component (A1), the amount of bound amorphous component (A2) and the amount of amorphous component (A3) of the PVA film. At this time, after standing at 30℃for 30 minutes, pulse NMR measurement was performed to determine the amount of crystalline component (A1), the amount of bound amorphous component (A2) and the amount of amorphous component (A3) from the relaxation curve thus obtained as (A1), respectively 30℃ 、(A2) 30℃ And (A3) 30℃ . After standing at 50℃for 30 minutes, pulse NMR measurement was performed to obtain a crystalline component (A1), a bound amorphous component (A2) and an amorphous component (A3) based on the relaxation curve obtained thereby, which were defined as (A1) 50℃ 、(A2) 50℃ And (A3) 50℃ . And, calculate (A2) based on the obtained value 50℃ /(A2) 30℃ And (A2) 50℃ /(A1) 50℃ 。
< measurement of swelling degree of PVA film >
About 1.5g of a test piece was cut out from the PVA film obtained in the following examples or comparative examples. Next, the test piece was immersed in 1000g of distilled water at 30 ℃. After dipping for 30 minutes, the test piece was taken out, and after sucking the surface water with a filter paper, the mass (We) thereof was measured. Subsequently, the test piece was put into a hot air dryer, dried at 105℃for 16 hours, and then the mass (Wf) thereof was measured. The swelling degree of the PVA film was determined from the obtained masses We and Wf by the following formula.
Swelling degree (%) = (We/Wf) ×100
< evaluation of tensile fracture at high-speed stretching >
The stretch break at high-speed stretching was evaluated based on the number of breaks of PVA film at the time of producing a polarizing film in the following examples or comparative examples. That is, the maximum stretching speed of uniaxial stretching in the stretching treatment at the time of producing the polarizing film was set to be high (600%/min), the case where the number of breaks of the PVA film was 0 times within 60 minutes was evaluated as "a", the case where it was 1 time was evaluated as "B", the case where it was 2 times was evaluated as "C", and the case where it was 3 times or more was evaluated as "D".
Example 1
A film-forming stock solution (volatile fraction: 66 mass%) was prepared by melt-mixing 100 parts by mass of PVA (having a saponification degree of 99.9 mol%, and a polymerization degree of 2400), 10 parts by mass of glycerin as a plasticizer, 0.1 part by mass of lauric acid diethanolamide as a surfactant, and 217.6 parts by mass of water using a melt extruder. Then, the film-forming stock solution was filtered through a 270-mesh filter, and then discharged from the T die into a film form on a support (surface temperature: 98 ℃) to form a PVA film on the support. The entire surface of the PVA film, which was not in contact with the support, was dried by blowing hot air at a temperature of 98 c and a dew point of 14 degrees, at a speed of 5 m/sec, to obtain a PVA film (moisture content: 32 mass%). Next, the PVA film was peeled off from the support, and after further drying from the first drying roller to the final drying roller (19 th drying roller) located immediately before the heat treatment roller, the PVA film was peeled off from the final drying roller so that one surface and the other surface of the PVA film alternately contact each drying roller. At this time, the surface temperature of each drying roller from the first drying roller to the final drying roller was set at 75 ℃. Further, the PVA film was peeled from the final drying roll, and heat treatment was performed so that one surface of the PVA film was alternately contacted with each heat treatment roll. At this time, the heat treatment was performed using 2 heat treatment rolls, the surface temperatures of the heat treatment rolls were 108℃and the contact time between the PVA film and the heat treatment rolls was 12 seconds. Thus, a PVA film (width: 1200 mm) having a thickness of 30 μm was obtained.
The obtained PVA film was cut into 650mm wide, and the film was sequentially subjected to swelling treatment, dyeing treatment, crosslinking treatment, stretching treatment, washing treatment, and drying treatment, to continuously produce a polarizing film. The swelling treatment was carried out by uniaxial stretching to 2.00 times in the longitudinal direction while immersing in pure water (swelling treatment liquid) at 25 ℃. The dyeing treatment was performed by uniaxial stretching to 1.26 times in the longitudinal direction while immersing the substrate in a potassium iodide/iodine aqueous dyeing solution (dyeing treatment solution) (potassium iodide/iodine (mass ratio) =23, iodine concentration 0.03 to 0.05 mass%) at a temperature of 32 ℃. In the dyeing treatment, the iodine concentration in the dyeing treatment liquid is adjusted to be in the range of 0.03 to 0.05 mass% so that the monomer transmittance of the polarizing film obtained after uniaxial stretching in the stretching treatment is in the range of 43.5% ± 0.2%. The crosslinking treatment was carried out by uniaxially stretching the impregnated side to 1.19 times in the longitudinal direction in an aqueous boric acid solution (crosslinking treatment liquid) at 32 ℃. The stretching treatment was carried out by uniaxial stretching to 2.00 times in the longitudinal direction while immersing the substrate in an aqueous boric acid/potassium iodide solution (stretching solution) (boric acid concentration: 2.8 mass% and potassium iodide concentration: 5 mass%) at 55 ℃. The maximum stretching speed of uniaxial stretching in this stretching treatment was 600%/min. The washing treatment was performed by immersing in an aqueous solution of potassium iodide/boric acid (washing treatment liquid) (potassium iodide concentration 3 to 6 mass% and boric acid concentration 1.5 mass%) at 22 ℃ for 12 seconds without stretching.
Examples 2 to 4 and comparative examples 1 and 2
PVA film production and evaluation were performed in the same manner as in example 1 except that the conditions for producing the PVA film (mesh size of the mesh filter, surface temperature of the support, hot air temperature on the surface not in contact with the support, hot air dew point on the non-contact surface, temperature of the heat treatment roller, film thickness, etc.) were changed as shown in Table 1. The results are shown in Table 1.
From the above results, it can be seen that: the PVA film of the present invention can suppress breakage during uniaxial stretching even when the maximum stretching speed is set to a high speed (600%/min) during uniaxial stretching in producing an optical film such as a polarizing film.
Claims (8)
1. A polyvinyl alcohol film wherein the amount of bound amorphous component calculated from the relaxation curve obtained by pulse NMR measurement in a 3 mass% boric acid heavy aqueous solution at 50 ℃ is set to (A2) 50℃ ，
The bound amorphous component calculated from the relaxation curve obtained by pulse NMR measurement in a 3 mass% boric acid heavy aqueous solution at 30℃was set as (A2) 30℃ In the time-course of which the first and second contact surfaces,
(A2) 50℃ relative (A2) 30℃ Ratio ((A2) 50℃ /(A2) 30℃ ) 0.20 to 0.65.
2. The polyvinyl alcohol film according to claim 1, wherein the (A2) 50℃ Is not more than 15 and is not more than,
the amount of the crystal component calculated from the relaxation curve obtained by pulse NMR measurement in a 3% by mass boric acid heavy aqueous solution at 50℃was set to A1 50℃ In the time-course of which the first and second contact surfaces,
(A2) 50℃ relative (A1) 50℃ Ratio ((A2) 50℃ /(A1) 50℃ ) 0.60 to 1.6.
3. The polyvinyl alcohol film according to claim 1 or 2, having a swelling degree of 170 to 220%.
4. The polyvinyl alcohol film according to any one of claims 1 to 3, wherein the polyvinyl alcohol contained in the polyvinyl alcohol film has a polymerization degree of 2,000 to 2,700.
5. The polyvinyl alcohol film according to any one of claims 1 to 4, which is a raw film for producing an optical film.
6. The polyvinyl alcohol film according to claim 5, wherein the optical film is a polarizing film.
7. A polarizing film produced using the polyvinyl alcohol film according to claim 6.
8. A polarizing plate comprising a protective film attached to at least one side of the polarizing film according to claim 7.
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| JP2020-196400 | 2020-11-26 | ||
| JP2020196400 | 2020-11-26 | ||
| PCT/JP2021/042861 WO2022113959A1 (en) | 2020-11-26 | 2021-11-22 | Polyvinyl alcohol film, polarizing film using same, and polarizing plate |
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| JP (1) | JPWO2022113959A1 (en) |
| KR (1) | KR20230112129A (en) |
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| JPS648909U (en) | 1987-07-06 | 1989-01-18 | ||
| JP6420153B2 (en) * | 2013-08-09 | 2018-11-07 | 株式会社クラレ | Vinyl alcohol polymer film |
| CN107000270B (en) * | 2014-12-12 | 2019-08-13 | 株式会社可乐丽 | Polyvinyl alcohol film and its manufacturing method |
| KR101819414B1 (en) * | 2016-08-10 | 2018-01-16 | 스미또모 가가꾸 가부시키가이샤 | A polarizing film |
| WO2019054487A1 (en) * | 2017-09-15 | 2019-03-21 | 株式会社クラレ | Polyvinyl alcohol film and method for manufacturing same |
| US11859063B2 (en) * | 2018-03-30 | 2024-01-02 | Sekisui Chemical Co., Ltd. | Poly(vinyl alcohol) film and production method for polarizing film |
| EP3904437A4 (en) * | 2018-12-28 | 2022-09-21 | Kuraray Co., Ltd. | Water-soluble film and package |
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