CN118574953A - Polyvinyl alcohol fiber, fiber structure, and method for producing same - Google Patents
Polyvinyl alcohol fiber, fiber structure, and method for producing same Download PDFInfo
- Publication number
- CN118574953A CN118574953A CN202380017553.5A CN202380017553A CN118574953A CN 118574953 A CN118574953 A CN 118574953A CN 202380017553 A CN202380017553 A CN 202380017553A CN 118574953 A CN118574953 A CN 118574953A
- Authority
- CN
- China
- Prior art keywords
- polyvinyl alcohol
- fiber
- shrinkage
- stretching
- dry
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 229920002451 polyvinyl alcohol Polymers 0.000 title claims abstract description 244
- 239000004372 Polyvinyl alcohol Substances 0.000 title claims abstract description 227
- 239000000835 fiber Substances 0.000 title claims abstract description 222
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 26
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 claims abstract description 39
- 238000009987 spinning Methods 0.000 claims description 47
- 239000004745 nonwoven fabric Substances 0.000 claims description 39
- 238000001035 drying Methods 0.000 claims description 17
- 238000010438 heat treatment Methods 0.000 claims description 17
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 16
- 125000000524 functional group Chemical group 0.000 claims description 16
- 125000005395 methacrylic acid group Chemical group 0.000 claims description 14
- 239000003960 organic solvent Substances 0.000 claims description 11
- 239000004753 textile Substances 0.000 claims description 4
- 235000019422 polyvinyl alcohol Nutrition 0.000 description 217
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 111
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 description 92
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 78
- 239000000178 monomer Substances 0.000 description 28
- 239000002250 absorbent Substances 0.000 description 25
- 238000010521 absorption reaction Methods 0.000 description 25
- 238000004090 dissolution Methods 0.000 description 24
- 229920000642 polymer Polymers 0.000 description 24
- 239000011148 porous material Substances 0.000 description 24
- 238000007127 saponification reaction Methods 0.000 description 24
- 238000000034 method Methods 0.000 description 23
- 239000002904 solvent Substances 0.000 description 23
- 229920001567 vinyl ester resin Polymers 0.000 description 20
- 239000006096 absorbing agent Substances 0.000 description 19
- 230000002745 absorbent Effects 0.000 description 14
- 238000006116 polymerization reaction Methods 0.000 description 13
- 150000003839 salts Chemical class 0.000 description 13
- 238000003756 stirring Methods 0.000 description 13
- BAPJBEWLBFYGME-UHFFFAOYSA-N Methyl acrylate Chemical compound COC(=O)C=C BAPJBEWLBFYGME-UHFFFAOYSA-N 0.000 description 12
- 229920001577 copolymer Polymers 0.000 description 12
- 239000007788 liquid Substances 0.000 description 11
- 210000002700 urine Anatomy 0.000 description 11
- 238000007654 immersion Methods 0.000 description 10
- LVHBHZANLOWSRM-UHFFFAOYSA-N methylenebutanedioic acid Natural products OC(=O)CC(=C)C(O)=O LVHBHZANLOWSRM-UHFFFAOYSA-N 0.000 description 10
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 description 9
- 238000000605 extraction Methods 0.000 description 9
- 239000000463 material Substances 0.000 description 9
- 239000002504 physiological saline solution Substances 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 8
- 238000005259 measurement Methods 0.000 description 8
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 6
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 6
- -1 N-methacrylamide Chemical compound 0.000 description 6
- 238000007334 copolymerization reaction Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- JAHNSTQSQJOJLO-UHFFFAOYSA-N 2-(3-fluorophenyl)-1h-imidazole Chemical compound FC1=CC=CC(C=2NC=CN=2)=C1 JAHNSTQSQJOJLO-UHFFFAOYSA-N 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 4
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 238000001891 gel spinning Methods 0.000 description 4
- 238000002156 mixing Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 239000011780 sodium chloride Substances 0.000 description 4
- 229920002554 vinyl polymer Polymers 0.000 description 4
- 238000002166 wet spinning Methods 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical group N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 3
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 3
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 description 3
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 230000001747 exhibiting effect Effects 0.000 description 3
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 238000007711 solidification Methods 0.000 description 3
- 230000008023 solidification Effects 0.000 description 3
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-Butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 description 2
- OIYTYGOUZOARSH-UHFFFAOYSA-N 4-methoxy-2-methylidene-4-oxobutanoic acid Chemical compound COC(=O)CC(=C)C(O)=O OIYTYGOUZOARSH-UHFFFAOYSA-N 0.000 description 2
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 2
- SOGAXMICEFXMKE-UHFFFAOYSA-N Butylmethacrylate Chemical compound CCCCOC(=O)C(C)=C SOGAXMICEFXMKE-UHFFFAOYSA-N 0.000 description 2
- 229920000742 Cotton Polymers 0.000 description 2
- 241000196324 Embryophyta Species 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 2
- IMROMDMJAWUWLK-UHFFFAOYSA-N Ethenol Chemical compound OC=C IMROMDMJAWUWLK-UHFFFAOYSA-N 0.000 description 2
- JIGUQPWFLRLWPJ-UHFFFAOYSA-N Ethyl acrylate Chemical compound CCOC(=O)C=C JIGUQPWFLRLWPJ-UHFFFAOYSA-N 0.000 description 2
- 239000005977 Ethylene Substances 0.000 description 2
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- NTIZESTWPVYFNL-UHFFFAOYSA-N Methyl isobutyl ketone Chemical compound CC(C)CC(C)=O NTIZESTWPVYFNL-UHFFFAOYSA-N 0.000 description 2
- UIHCLUNTQKBZGK-UHFFFAOYSA-N Methyl isobutyl ketone Natural products CCC(C)C(C)=O UIHCLUNTQKBZGK-UHFFFAOYSA-N 0.000 description 2
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 2
- WHNWPMSKXPGLAX-UHFFFAOYSA-N N-Vinyl-2-pyrrolidone Chemical compound C=CN1CCCC1=O WHNWPMSKXPGLAX-UHFFFAOYSA-N 0.000 description 2
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 2
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 150000008064 anhydrides Chemical class 0.000 description 2
- 210000001124 body fluid Anatomy 0.000 description 2
- 239000010839 body fluid Substances 0.000 description 2
- 239000004202 carbamide Substances 0.000 description 2
- 230000008602 contraction Effects 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- ZWWQRMFIZFPUAA-UHFFFAOYSA-N dimethyl 2-methylidenebutanedioate Chemical compound COC(=O)CC(=C)C(=O)OC ZWWQRMFIZFPUAA-UHFFFAOYSA-N 0.000 description 2
- 229920001971 elastomer Polymers 0.000 description 2
- 238000004049 embossing Methods 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
- SUPCQIBBMFXVTL-UHFFFAOYSA-N ethyl 2-methylprop-2-enoate Chemical compound CCOC(=O)C(C)=C SUPCQIBBMFXVTL-UHFFFAOYSA-N 0.000 description 2
- 239000004744 fabric Substances 0.000 description 2
- 235000013305 food Nutrition 0.000 description 2
- 230000036541 health Effects 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 238000005470 impregnation Methods 0.000 description 2
- 150000002576 ketones Chemical class 0.000 description 2
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical compound [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 150000002734 metacrylic acid derivatives Chemical class 0.000 description 2
- FQPSGWSUVKBHSU-UHFFFAOYSA-N methacrylamide Chemical class CC(=C)C(N)=O FQPSGWSUVKBHSU-UHFFFAOYSA-N 0.000 description 2
- PNJWIWWMYCMZRO-UHFFFAOYSA-N pent‐4‐en‐2‐one Natural products CC(=O)CC=C PNJWIWWMYCMZRO-UHFFFAOYSA-N 0.000 description 2
- 230000000379 polymerizing effect Effects 0.000 description 2
- BOQSSGDQNWEFSX-UHFFFAOYSA-N propan-2-yl 2-methylprop-2-enoate Chemical compound CC(C)OC(=O)C(C)=C BOQSSGDQNWEFSX-UHFFFAOYSA-N 0.000 description 2
- LYBIZMNPXTXVMV-UHFFFAOYSA-N propan-2-yl prop-2-enoate Chemical compound CC(C)OC(=O)C=C LYBIZMNPXTXVMV-UHFFFAOYSA-N 0.000 description 2
- NHARPDSAXCBDDR-UHFFFAOYSA-N propyl 2-methylprop-2-enoate Chemical compound CCCOC(=O)C(C)=C NHARPDSAXCBDDR-UHFFFAOYSA-N 0.000 description 2
- PNXMTCDJUBJHQJ-UHFFFAOYSA-N propyl prop-2-enoate Chemical compound CCCOC(=O)C=C PNXMTCDJUBJHQJ-UHFFFAOYSA-N 0.000 description 2
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 2
- 238000004080 punching Methods 0.000 description 2
- 238000007378 ring spinning Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- 230000001629 suppression Effects 0.000 description 2
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 2
- 239000002759 woven fabric Substances 0.000 description 2
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 description 2
- BQCIDUSAKPWEOX-UHFFFAOYSA-N 1,1-Difluoroethene Chemical compound FC(F)=C BQCIDUSAKPWEOX-UHFFFAOYSA-N 0.000 description 1
- DLKQHBOKULLWDQ-UHFFFAOYSA-N 1-bromonaphthalene Chemical compound C1=CC=C2C(Br)=CC=CC2=C1 DLKQHBOKULLWDQ-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
- OEPOKWHJYJXUGD-UHFFFAOYSA-N 2-(3-phenylmethoxyphenyl)-1,3-thiazole-4-carbaldehyde Chemical compound O=CC1=CSC(C=2C=C(OCC=3C=CC=CC=3)C=CC=2)=N1 OEPOKWHJYJXUGD-UHFFFAOYSA-N 0.000 description 1
- GOXQRTZXKQZDDN-UHFFFAOYSA-N 2-Ethylhexyl acrylate Chemical compound CCCCC(CC)COC(=O)C=C GOXQRTZXKQZDDN-UHFFFAOYSA-N 0.000 description 1
- PGYJSURPYAAOMM-UHFFFAOYSA-N 2-ethenoxy-2-methylpropane Chemical compound CC(C)(C)OC=C PGYJSURPYAAOMM-UHFFFAOYSA-N 0.000 description 1
- GNUGVECARVKIPH-UHFFFAOYSA-N 2-ethenoxypropane Chemical compound CC(C)OC=C GNUGVECARVKIPH-UHFFFAOYSA-N 0.000 description 1
- WDQMWEYDKDCEHT-UHFFFAOYSA-N 2-ethylhexyl 2-methylprop-2-enoate Chemical compound CCCCC(CC)COC(=O)C(C)=C WDQMWEYDKDCEHT-UHFFFAOYSA-N 0.000 description 1
- FVSAFCHCUDOKSI-UHFFFAOYSA-N 2-methylprop-2-enamide;propane-1-sulfonic acid Chemical compound CC(=C)C(N)=O.CCCS(O)(=O)=O FVSAFCHCUDOKSI-UHFFFAOYSA-N 0.000 description 1
- RUMACXVDVNRZJZ-UHFFFAOYSA-N 2-methylpropyl 2-methylprop-2-enoate Chemical compound CC(C)COC(=O)C(C)=C RUMACXVDVNRZJZ-UHFFFAOYSA-N 0.000 description 1
- CFVWNXQPGQOHRJ-UHFFFAOYSA-N 2-methylpropyl prop-2-enoate Chemical compound CC(C)COC(=O)C=C CFVWNXQPGQOHRJ-UHFFFAOYSA-N 0.000 description 1
- OFNISBHGPNMTMS-UHFFFAOYSA-N 3-methylideneoxolane-2,5-dione Chemical compound C=C1CC(=O)OC1=O OFNISBHGPNMTMS-UHFFFAOYSA-N 0.000 description 1
- RTTAGBVNSDJDTE-UHFFFAOYSA-N 4-ethoxy-2-methylidene-4-oxobutanoic acid Chemical compound CCOC(=O)CC(=C)C(O)=O RTTAGBVNSDJDTE-UHFFFAOYSA-N 0.000 description 1
- ZWAPMFBHEQZLGK-UHFFFAOYSA-N 5-(dimethylamino)-2-methylidenepentanamide Chemical compound CN(C)CCCC(=C)C(N)=O ZWAPMFBHEQZLGK-UHFFFAOYSA-N 0.000 description 1
- FLCAEMBIQVZWIF-UHFFFAOYSA-N 6-(dimethylamino)-2-methylhex-2-enamide Chemical compound CN(C)CCCC=C(C)C(N)=O FLCAEMBIQVZWIF-UHFFFAOYSA-N 0.000 description 1
- JTHZUSWLNCPZLX-UHFFFAOYSA-N 6-fluoro-3-methyl-2h-indazole Chemical compound FC1=CC=C2C(C)=NNC2=C1 JTHZUSWLNCPZLX-UHFFFAOYSA-N 0.000 description 1
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 description 1
- OSDWBNJEKMUWAV-UHFFFAOYSA-N Allyl chloride Chemical compound ClCC=C OSDWBNJEKMUWAV-UHFFFAOYSA-N 0.000 description 1
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 description 1
- 206010016654 Fibrosis Diseases 0.000 description 1
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 1
- 239000004831 Hot glue Substances 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 206010021639 Incontinence Diseases 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 compound CC(=C)OC(C)=O HETCEOQFVDFGSY-UHFFFAOYSA-N 0.000 description 1
- 235000003403 Limnocharis flava Nutrition 0.000 description 1
- 244000278243 Limnocharis flava Species 0.000 description 1
- GYCMBHHDWRMZGG-UHFFFAOYSA-N Methylacrylonitrile Chemical compound CC(=C)C#N GYCMBHHDWRMZGG-UHFFFAOYSA-N 0.000 description 1
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 description 1
- CNCOEDDPFOAUMB-UHFFFAOYSA-N N-Methylolacrylamide Chemical compound OCNC(=O)C=C CNCOEDDPFOAUMB-UHFFFAOYSA-N 0.000 description 1
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- OFOBLEOULBTSOW-UHFFFAOYSA-N Propanedioic acid Natural products OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 1
- XBDQKXXYIPTUBI-UHFFFAOYSA-M Propionate Chemical compound CCC([O-])=O XBDQKXXYIPTUBI-UHFFFAOYSA-M 0.000 description 1
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 1
- ZMZDMBWJUHKJPS-UHFFFAOYSA-M Thiocyanate anion Chemical compound [S-]C#N ZMZDMBWJUHKJPS-UHFFFAOYSA-M 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
- KXKVLQRXCPHEJC-UHFFFAOYSA-N acetic acid trimethyl ester Natural products COC(C)=O KXKVLQRXCPHEJC-UHFFFAOYSA-N 0.000 description 1
- 150000003926 acrylamides Chemical class 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000007605 air drying Methods 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 150000001336 alkenes Chemical class 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 150000001491 aromatic compounds Chemical class 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000036760 body temperature Effects 0.000 description 1
- CQEYYJKEWSMYFG-UHFFFAOYSA-N butyl acrylate Chemical compound CCCCOC(=O)C=C CQEYYJKEWSMYFG-UHFFFAOYSA-N 0.000 description 1
- 239000001110 calcium chloride Substances 0.000 description 1
- 229910001628 calcium chloride Inorganic materials 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 238000009960 carding Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 235000014113 dietary fatty acids Nutrition 0.000 description 1
- ZEFVHSWKYCYFFL-UHFFFAOYSA-N diethyl 2-methylidenebutanedioate Chemical compound CCOC(=O)CC(=C)C(=O)OCC ZEFVHSWKYCYFFL-UHFFFAOYSA-N 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- LOKCTEFSRHRXRJ-UHFFFAOYSA-I dipotassium trisodium dihydrogen phosphate hydrogen phosphate dichloride Chemical compound P(=O)(O)(O)[O-].[K+].P(=O)(O)([O-])[O-].[Na+].[Na+].[Cl-].[K+].[Cl-].[Na+] LOKCTEFSRHRXRJ-UHFFFAOYSA-I 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- GMSCBRSQMRDRCD-UHFFFAOYSA-N dodecyl 2-methylprop-2-enoate Chemical compound CCCCCCCCCCCCOC(=O)C(C)=C GMSCBRSQMRDRCD-UHFFFAOYSA-N 0.000 description 1
- 238000000578 dry spinning Methods 0.000 description 1
- 239000000839 emulsion Substances 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
- GLVVKKSPKXTQRB-UHFFFAOYSA-N ethenyl dodecanoate Chemical compound CCCCCCCCCCCC(=O)OC=C GLVVKKSPKXTQRB-UHFFFAOYSA-N 0.000 description 1
- GFJVXXWOPWLRNU-UHFFFAOYSA-N ethenyl formate Chemical compound C=COC=O GFJVXXWOPWLRNU-UHFFFAOYSA-N 0.000 description 1
- AFSIMBWBBOJPJG-UHFFFAOYSA-N ethenyl octadecanoate Chemical compound CCCCCCCCCCCCCCCCCC(=O)OC=C AFSIMBWBBOJPJG-UHFFFAOYSA-N 0.000 description 1
- BLZSRIYYOIZLJL-UHFFFAOYSA-N ethenyl pentanoate Chemical compound CCCCC(=O)OC=C BLZSRIYYOIZLJL-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
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000000194 fatty acid Substances 0.000 description 1
- 229930195729 fatty acid Natural products 0.000 description 1
- 230000004761 fibrosis Effects 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- XUCNUKMRBVNAPB-UHFFFAOYSA-N fluoroethene Chemical compound FC=C XUCNUKMRBVNAPB-UHFFFAOYSA-N 0.000 description 1
- 238000005187 foaming Methods 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 238000001879 gelation Methods 0.000 description 1
- 235000011187 glycerol Nutrition 0.000 description 1
- ZMZDMBWJUHKJPS-UHFFFAOYSA-N hydrogen thiocyanate Natural products SC#N ZMZDMBWJUHKJPS-UHFFFAOYSA-N 0.000 description 1
- 230000002209 hydrophobic effect Effects 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- PBOSTUDLECTMNL-UHFFFAOYSA-N lauryl acrylate Chemical compound CCCCCCCCCCCCOC(=O)C=C PBOSTUDLECTMNL-UHFFFAOYSA-N 0.000 description 1
- 231100000053 low toxicity Toxicity 0.000 description 1
- 230000014759 maintenance of location Effects 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
- XJRBAMWJDBPFIM-UHFFFAOYSA-N methyl vinyl ether Chemical compound COC=C XJRBAMWJDBPFIM-UHFFFAOYSA-N 0.000 description 1
- 239000002480 mineral oil Substances 0.000 description 1
- 235000010446 mineral oil Nutrition 0.000 description 1
- 230000000877 morphologic effect Effects 0.000 description 1
- WFKDPJRCBCBQNT-UHFFFAOYSA-N n,2-dimethylprop-2-enamide Chemical compound CNC(=O)C(C)=C WFKDPJRCBCBQNT-UHFFFAOYSA-N 0.000 description 1
- OMNKZBIFPJNNIO-UHFFFAOYSA-N n-(2-methyl-4-oxopentan-2-yl)prop-2-enamide Chemical compound CC(=O)CC(C)(C)NC(=O)C=C OMNKZBIFPJNNIO-UHFFFAOYSA-N 0.000 description 1
- DNTMQTKDNSEIFO-UHFFFAOYSA-N n-(hydroxymethyl)-2-methylprop-2-enamide Chemical compound CC(=C)C(=O)NCO DNTMQTKDNSEIFO-UHFFFAOYSA-N 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
- ZIWDVJPPVMGJGR-UHFFFAOYSA-N n-ethyl-2-methylprop-2-enamide Chemical compound CCNC(=O)C(C)=C ZIWDVJPPVMGJGR-UHFFFAOYSA-N 0.000 description 1
- SWPMNMYLORDLJE-UHFFFAOYSA-N n-ethylprop-2-enamide Chemical compound CCNC(=O)C=C SWPMNMYLORDLJE-UHFFFAOYSA-N 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- HMZGPNHSPWNGEP-UHFFFAOYSA-N octadecyl 2-methylprop-2-enoate Chemical compound CCCCCCCCCCCCCCCCCCOC(=O)C(C)=C HMZGPNHSPWNGEP-UHFFFAOYSA-N 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000005022 packaging material 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
- 239000002953 phosphate buffered saline Substances 0.000 description 1
- 239000002798 polar solvent Substances 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- UIIIBRHUICCMAI-UHFFFAOYSA-N prop-2-ene-1-sulfonic acid Chemical compound OS(=O)(=O)CC=C UIIIBRHUICCMAI-UHFFFAOYSA-N 0.000 description 1
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-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
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000011550 stock solution Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 150000005846 sugar alcohols Polymers 0.000 description 1
- SJMYWORNLPSJQO-UHFFFAOYSA-N tert-butyl 2-methylprop-2-enoate Chemical compound CC(=C)C(=O)OC(C)(C)C SJMYWORNLPSJQO-UHFFFAOYSA-N 0.000 description 1
- ISXSCDLOGDJUNJ-UHFFFAOYSA-N tert-butyl prop-2-enoate Chemical compound CC(C)(C)OC(=O)C=C ISXSCDLOGDJUNJ-UHFFFAOYSA-N 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
- KOZCZZVUFDCZGG-UHFFFAOYSA-N vinyl benzoate Chemical compound C=COC(=O)C1=CC=CC=C1 KOZCZZVUFDCZGG-UHFFFAOYSA-N 0.000 description 1
- 239000011592 zinc chloride Substances 0.000 description 1
- 235000005074 zinc chloride Nutrition 0.000 description 1
Classifications
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
- D01F6/28—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
- D01F6/34—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds comprising unsaturated alcohols, acetals or ketals as the major constituent
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Artificial Filaments (AREA)
Abstract
The present invention provides a polyvinyl alcohol fiber having sufficient shrinkage and shrinkage stress when absorbing moisture at a temperature of room temperature or more, particularly about 35 ℃. The present invention provides a polyvinyl alcohol fiber, a fiber structure using the polyvinyl alcohol fiber, and a method for producing the polyvinyl alcohol fiber, wherein the polyvinyl alcohol fiber comprises a modified polyvinyl alcohol containing 1 mol% or more of carboxyl groups, and has a birefringence of 0.040 or more.
Description
Technical Field
The present invention relates to a polyvinyl alcohol fiber and a fiber structure containing the same. The present invention also relates to a method for producing a polyvinyl alcohol fiber.
Disposable diapers and incontinence pads as health products, sanitary napkins as living goods, and the like absorb body fluids to keep clean, and thus play an important role in daily life.
Absorbent articles intended for the purpose of absorbing moisture such as body fluids generally have the following structure: the moisture absorber is covered with paper or the like, a part of which is fixed by a hot melt adhesive or the like, and the moisture absorber is provided between a breathable polymer sheet which is in direct contact with the skin of the wearer and a water impermeable nonwoven fabric.
The water absorbent material is made of water-absorbent shrinkable fibers, which absorb water and shrink, thereby ensuring a flow path of water to the water absorbent material, and the water absorbing agent is brought into close contact with the human body to suppress leakage of liquid.
As such a water-absorbent shrinkable fiber, for example, patent document 1 discloses a high-speed shrinkable fiber comprising a modified polyvinyl alcohol containing 0.5 to 10 mol% of a carboxyl group, having a maximum shrinkage of 30% or more in water at 20 ℃, a time required for reaching 30% shrinkage of 10 seconds or less, a shrinkage stress in an as-grown state of 0.15g/d or more, a time until a shrinkage stress of 0.15g/d is developed of 10 seconds or less, and a shrinkage stress in water at 20 ℃ of 30% or more than that in the as-grown state of 0.03g/d or more, a dissolution loss of 45% or less when dispersed in water at 20 ℃, having a poor solubility in water, and shrinking in the presence of water.
Patent document 2 describes a water-absorbent shrinkable polyvinyl alcohol fiber having a shrinkage in water at 30 ℃ of 20 to 50%, a shrinkage in water at 30 ℃ of 0.2 to 0.7 relative to the maximum shrinkage, a wet elastic modulus of 0.1 to 3cN/dtex, and an ash content of 0.2 mass% or less.
Technical literature of the prior art
Patent literature
Patent document 1: japanese patent laid-open No. 62-215011
Patent document 2: japanese patent laid-open No. 2001-2626432
Disclosure of Invention
Technical problem to be solved by the invention
In the use of the health care product or the living product, since the moisture absorber absorbs moisture at about 35 ℃ which is close to the body temperature of the human body, the shrinkage rate of the water-absorbent shrinkable fiber when absorbing moisture at a temperature of at least room temperature or more is important.
Further, since the moisture absorber needs to be entirely contracted, the water-absorbent contractible fiber needs to have a sufficient contraction stress when absorbing moisture at a temperature of at least room temperature or more.
In a state where a large amount of moisture is absorbed by the moisture absorber, the shape of the moisture absorber deforms by its own weight, and the absorber moves between the air-permeable polymer sheet and the nonwoven fabric in the absorbent article. As a result, the moisture absorber may be unevenly present in the absorbent article, and the absorbent article may not sufficiently absorb moisture, resulting in leakage.
In order to prevent such leakage, the water-absorbent contractible fibers are required to retain the contractile stress of the shape of the water absorbent body after absorbing water.
However, the high-speed shrinkable fiber disclosed in patent document 1 may have a dissolution loss of 45% or less when dispersed in water at 20 ℃ and may have insufficient shrinkage stress when absorbing moisture at a temperature of room temperature or higher.
Further, the water-shrinkable polyvinyl alcohol fiber described in patent document 2 has a shrinkage of 20 to 50% in water at 30 ℃.
Therefore, in order to improve the shrinkage and the shrinkage stress, an absorbent article using a combination of water-absorbent shrinkable fibers and rubber threads is used. However, since the rubber thread is in a contracted state from before the absorbent article is used, it is a result of the large volume of the absorbent article before use.
Therefore, there is a demand for a shrinkable fiber having sufficient shrinkage and shrinkage stress when absorbing moisture at a temperature of room temperature or higher, particularly around 35 ℃.
The purpose of the present invention is to provide a polyvinyl alcohol fiber having sufficient shrinkage and shrinkage stress when absorbing moisture at a temperature of room temperature or more, particularly at about 35 ℃. The present invention also provides a fiber structure having at least a part of the polyvinyl alcohol fibers. The present invention also provides a method for producing the polyvinyl alcohol fiber.
Means for solving the technical problems
That is, the present invention includes the following preferred modes.
[1] A polyvinyl alcohol fiber comprising a modified polyvinyl alcohol containing 1 mol% or more of carboxyl groups and having a birefringence of 0.040 or more.
[2] The polyvinyl alcohol fiber according to the item [1], wherein,
The carboxyl group is included in at least one functional group selected from the group consisting of an acrylic group, a methacrylic group, and an itaconic group.
[3] The polyvinyl alcohol fiber according to the item [1] or [2], wherein,
The crystallinity is 30% to 60%.
[4] A fiber structure comprising at least a part of the polyvinyl alcohol-based fiber of any one of [1] to [3 ].
[5] The fiber structure according to the item [4], wherein,
The fiber structure body is non-woven fabrics or textile yarns.
Also, the present invention includes the following preferred modes.
[6] A method for producing a polyvinyl alcohol fiber, wherein,
A spinning dope containing 5 to 30 mass% of a modified polyvinyl alcohol containing 1 mol% or more of carboxyl groups is wet-or dry-wet-spun in a curing bath mainly containing an organic solvent having a curing ability for polyvinyl alcohol, and the total draw ratio in all the steps is 7 times or more at a temperature of 180 ℃ or more in any one of wet drawing, drying, dry drawing and heat treatment.
[7] The method for producing a polyvinyl alcohol fiber according to the item [6], wherein,
The total stretching ratio in all the steps is set to 7 times or more, and the stretching tension is set to 0.40cN/dtex or more.
[8] The method for producing a polyvinyl alcohol fiber according to the item [6] or [7], wherein,
The stretching temperature in the dry stretching step is 180 ℃ or higher.
Effects of the invention
According to the present invention, there are provided a polyvinyl alcohol fiber having sufficient shrinkage and shrinkage stress when absorbing moisture at a temperature of room temperature or more, particularly about 35 ℃, and a fiber structure having at least a part of the polyvinyl alcohol fiber. Also provided is a method for producing a polyvinyl alcohol fiber.
Detailed Description
In the present invention, a polyvinyl alcohol fiber having a modified polyvinyl alcohol containing 1 mol% or more of carboxyl groups and having a birefringence of 0.040 or more (hereinafter, also referred to as "the present polyvinyl alcohol fiber") is used, whereby a water-absorbent shrinkable fiber having a sufficient shrinkage and shrinkage stress when absorbing moisture at a temperature of room temperature or more, particularly about 35 ℃.
Polyvinyl alcohol is obtained by saponifying a vinyl ester polymer obtained by polymerizing a vinyl ester monomer. Examples of the vinyl ester monomer include vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate, and vinyl versatate, and among these, vinyl acetate is preferable.
The vinyl ester polymer is preferably a polymer obtained by using one or more vinyl ester monomers as monomers, more preferably a polymer obtained by using one vinyl ester monomer as monomers. The vinyl ester polymer may be a copolymer of one or more vinyl ester monomers and other monomers copolymerizable therewith.
Examples of the other monomer copolymerizable with the vinyl ester monomer include ethylene; olefins having 3 to 30 carbon atoms such as propylene, 1-butene and isobutylene; acrylic acid or a salt thereof; acrylic esters such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, and stearyl acrylate; methacrylic acid or a salt thereof; methacrylates such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, and stearyl methacrylate; acrylamide derivatives such as acrylamide, N-methacrylamide, N-ethylacrylamide, N-dimethylacrylamide, diacetone acrylamide, acrylamide propane sulfonic acid or a salt thereof, dimethylaminopropyl acrylamide or a salt thereof, and N-methylolacrylamide or a derivative thereof; methacrylamide derivatives such as methacrylamide, N-methyl methacrylamide, N-ethyl methacrylamide, methacrylamide propane sulfonic acid or salt thereof, dimethylaminopropyl methacrylamide or salt thereof, N-hydroxymethyl methacrylamide or derivative thereof; n-vinyl amides such as N-vinyl formamide, N-vinyl acetamide and N-vinyl pyrrolidone; vinyl ethers such as methyl vinyl ether, vinyl ethyl ether, n-propyl vinyl ether, isopropyl vinyl ether, vinyl n-butyl ether, vinyl isobutyl ether, t-butyl vinyl ether, dodecyl vinyl ether, and octadecyl vinyl ether; vinyl cyanide such as acrylonitrile and methacrylonitrile; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl fluoride, and vinylidene fluoride; propylene 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; isopropenyl acetate, and the like. The vinyl ester polymer described above can have structural units derived from one or two or more of these other monomers.
Examples of the modified polyvinyl alcohol containing a carboxyl group include a method of copolymerizing a carboxyl group-containing monomer when polymerizing the vinyl ester monomer or copolymerizing another monomer copolymerizable with the vinyl ester monomer, if necessary, with the vinyl ester monomer, and saponifying the obtained vinyl ester copolymer, and a method of introducing these functional groups into a polyvinyl alcohol synthesized in advance.
The carboxyl group is preferably contained in a functional group such as an acrylic group, a methacrylic group, or an itaconic group, for example, from the viewpoint of copolymerization with a vinyl ester or stability at the time of saponification, and the modified polyvinyl alcohol obtained by copolymerizing a monomer containing these functional groups with the vinyl ester monomer is preferable.
The acrylic group is a residue obtained by removing hydrogen other than a hydroxyl group from acrylic acid, and the hydrogen to be removed is not particularly limited as long as it is a hydroxyl group. The same applies to methacrylic groups and itaconic groups.
Examples of the monomer having an acrylic group in the functional group include acrylic acid or a salt thereof, and acrylic esters such as methyl acrylate, ethyl acrylate, n-propyl acrylate, and isopropyl acrylate. Among them, acrylic acid and methyl acrylate are preferable from the viewpoints of copolymerization with vinyl ester, stability at the time of saponification, and the like.
Examples of the monomer containing a methacrylic group include methacrylic acid or a salt thereof, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, and other methacrylates. Among them, methacrylic acid and methyl methacrylate are preferable from the viewpoints of copolymerization with vinyl ester, stability at the time of saponification, and the like.
Examples of the monomer containing an itaconic acid group include itaconic acid or a salt thereof, itaconic acid esters such as monomethyl itaconate, dimethyl itaconate, monoethyl itaconate and diethyl itaconate, itaconic anhydride and derivatives thereof, and the like. Among them, itaconic acid, monomethyl itaconate, and dimethyl itaconate are preferable from the viewpoints of copolymerization with vinyl esters, stability at the time of saponification, and the like.
Among the monomers, a monomer containing at least one functional group selected from the group consisting of an acrylic group, a methacrylic group, and an itaconic group is preferable.
One or more than two kinds of monomers having these functional groups may be used, but one kind of monomer is preferably used.
In the case of producing the monomer having the functional group and the vinyl ester monomer by copolymerization, the content of carboxyl groups in the obtained modified polyvinyl alcohol can be adjusted by appropriately adjusting the amount of the monomer at the time of copolymerization.
When these functional groups are subsequently introduced into polyvinyl alcohol, the content of the desired functional groups can be obtained by adjusting the amount of polyvinyl alcohol and the amount of the compound having the functional groups.
The carboxyl group in the modified polyvinyl alcohol may be condensed with a hydroxyl group in a molecule or other molecules to form an ester bond in a molecule or between molecules, or may exist as a metal salt with a metal.
In the present invention, the content of carboxyl groups in the modified polyvinyl alcohol (hereinafter, also referred to as "modified amount") is 1 mol% or more in the modified polyvinyl alcohol from the viewpoint of shrinkage when absorbing moisture at room temperature or more and from the viewpoint of water solubility when discarded. The content of the carboxyl group is preferably 1.5 mol% or more, more preferably 2 mol% or more.
The content of carboxyl groups is preferably 20 mol% or less, more preferably 6 mol% or less, further preferably 4 mol% or less, and particularly preferably 3 mol% or less, from the viewpoint of shrinkage stress when absorbing moisture at room temperature or more.
The modified polyvinyl alcohol may contain a functional group other than a carboxyl group, and may be modified with other components as long as the effect of the present invention is not impaired. Examples of the other functional group or component include allylsulfonic acid, vinylpyrrolidone, and ethylene.
The polymerization degree (viscosity average polymerization degree) of the modified polyvinyl alcohol is preferably 2400 or less, more preferably 1800 or less, from the viewpoints of mechanical strength and suppression of insolubilization by saponification. If the polymerization degree is too high, the solubility in water may be lowered, and disposal of the water absorbent after use may be an environmental burden. Further, from the viewpoint of suppressing the decrease in spinning property and the adhesion between fibers, and maintaining the mechanical properties and quality of the fibers and the fiber structure, the polymerization degree is preferably 500 or more, more preferably 700 or more, and particularly preferably 1000 or more.
As described later, the polymerization degree can be determined by measurement in accordance with JIS K6726.
The polyvinyl alcohol fiber comprises the modified polyvinyl alcohol. The polyvinyl alcohol fiber may contain one or more of the modified polyvinyl alcohols, and may contain other polyvinyl alcohols than the modified polyvinyl alcohols. Further, other polymers than polyvinyl alcohol may be contained.
For example, the polyvinyl alcohol fibers include:
(a) A polyvinyl alcohol fiber comprising one or more of the modified polyvinyl alcohols;
(b) And polyvinyl alcohol fibers comprising the modified polyvinyl alcohol and a polyvinyl alcohol having no carboxyl group (hereinafter, sometimes referred to as a polyvinyl alcohol polymer (a)).
Further, when a polymer other than polyvinyl alcohol is contained, examples thereof include:
(c) And a polyvinyl alcohol fiber composed of the modified polyvinyl alcohol, the polyvinyl alcohol polymer (a), or a polyvinyl alcohol fiber composed of the modified polyvinyl alcohol and a polymer other than polyvinyl alcohol (hereinafter, also referred to as "other polymer").
In the above (a), at least one of the kind, the amount of modification, the degree of saponification, and the degree of polymerization of the carboxyl group-containing functional groups of the plurality of modified polyvinyl alcohols is different. In the above (b), the degree of saponification and the degree of polymerization of the modified polyvinyl alcohol and the polyvinyl alcohol polymer (a) may be different or the same.
When the polyvinyl alcohol fiber contains polyvinyl alcohol other than modified polyvinyl alcohol or a polymer other than polyvinyl alcohol, the content of the modified polyvinyl alcohol in the polyvinyl alcohol fiber is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, based on 100% by mass of the total mass of the polyvinyl alcohol fiber.
The polyvinyl alcohol fiber is preferably 100% by mass of the modified polyvinyl alcohol, and more preferably 100% by mass of the modified polyvinyl alcohol.
The polyvinyl alcohol fiber can be produced by spinning these modified polyvinyl alcohols and the like.
The birefringence of the polyvinyl alcohol fiber is 0.040 or more.
The birefringence is affected by the orientation state of the amorphous and crystalline portions of the polymer, the residual stress in the interior, and the like. It is considered that the polyvinyl alcohol fiber having a birefringence of 0.040 or more exhibits high shrinkage and shrinkage stress due to the influence of these alignment states and residual stress when absorbing moisture.
The birefringence of the polyvinyl alcohol fiber is preferably 0.041 or more, more preferably 0.042 or more, and even more preferably 0.045 or more.
The upper limit of the birefringence is not particularly limited, but is usually 0.052 or less.
The saponification degree of the polyvinyl alcohol fiber is preferably 97 mol% or more. More preferably 98 mol% or more, and still more preferably 99 mol% or more. When the saponification degree is less than the above-mentioned value, the mechanical strength of the present polyvinyl alcohol fiber may be poor, and for example, the shape retention of the moisture absorber may be insufficient. When the saponification degree is less than the above-mentioned value, the dissolution rate at about 35 ℃ may be high. When the saponification degree is high, the shrinkage stress may be further increased. The saponification degree is usually 100 mol% or less, preferably 99.5 mol% or less.
As described above, the present polyvinyl alcohol fiber may contain one or two or more kinds of modified polyvinyl alcohol. When the modified polyvinyl alcohol is one type, the modified polyvinyl alcohol having a saponification degree in the above range can be used for spinning by a method described later to produce a desired polyvinyl alcohol fiber.
In the case of using two or more modified polyvinyl alcohols, the addition property is established in the saponification degree of each modified polyvinyl alcohol, and therefore, the saponification degree of each modified polyvinyl alcohol may be determined by measurement or the like in advance, and the saponification degree of the entire polyvinyl alcohol fiber obtained by the following formula (1) may be determined, and the blending amount of the polyvinyl alcohol to be used may be adjusted so that the obtained saponification degree falls within the above-mentioned range.
The saponification degree of polyvinyl alcohol can be usually determined by the method described in JIS K6726.
Degree of saponification (mol%) of polyvinyl alcohol fiber
＝[Σ(ni×Mi)]/100(1)
Ni: saponification degree (mol%) of each modified polyvinyl alcohol
Mi: ratio (mass%) of each modified polyvinyl alcohol in the polyvinyl alcohol fiber
In the case where the polyvinyl alcohol fiber contains a polymer other than modified polyvinyl alcohol, the ratio of the polymer other than modified polyvinyl alcohol in the formula (1) may be substituted into Mi. In addition, when the polymer other than the modified polyvinyl alcohol in ni is polyvinyl alcohol, the saponification degree thereof may be substituted, and when the polymer other than polyvinyl alcohol is other than polyvinyl alcohol, 0 (zero) may be substituted.
From the viewpoints of shrinkage characteristics and water solubility, the crystallinity of the present polyvinyl alcohol fiber is preferably 60% or less, more preferably 50% or less. From the viewpoints of shrinkage stress, fibrosis and mechanical strength, it is preferably 30% or more, more preferably 40% or more.
The crystallinity can be controlled by the polymerization degree, saponification degree, kind of carboxyl group-containing functional group, modification amount, and the like of the modified polyvinyl alcohol constituting the polyvinyl alcohol fiber.
In the production of a polyvinyl alcohol fiber, a spinning dope containing the modified polyvinyl alcohol is prepared. The solvent of the dope may be water, but since a fiber having high mechanical properties and dimensional stability and a substantially circular and homogeneous cross section can be obtained and the water-in-melt temperature can be lowered as compared with the case where the solvent of the dope is water, the solvent of the dope is preferably an organic solvent because the solvent is excellent in water solubility at the time of disposal.
Examples of the organic solvent include polar solvents such as dimethyl sulfoxide (hereinafter, also referred to as "DMSO"), dimethylacetamide, dimethylformamide, and N-methylpyrrolidone, and mixtures of polyhydric alcohols such as glycerin and ethylene glycol, and swellable metal salts thereof with thiocyanate, lithium chloride, calcium chloride, and zinc chloride, and mixtures of these solvents with each other or with water. Especially, DMSO is most preferable from the viewpoints of low-temperature solubility, low toxicity, low corrosiveness, and the like.
The concentration of the polyvinyl alcohol in the spinning dope is in the range of 5 to 30 mass%. Here, the concentration of polyvinyl alcohol is the concentration of modified polyvinyl alcohol when the polyvinyl alcohol fiber contains only modified polyvinyl alcohol, and is the total concentration of both when the polyvinyl alcohol fiber contains modified polyvinyl alcohol and the vinyl alcohol polymer (a).
In the case where the polyvinyl alcohol fiber contains the other polymer, the concentration of the other polymer is not contained in the concentration of the polyvinyl alcohol.
In the case where the solvent of the spinning dope is an organic solvent, it is preferable to dissolve these polymers while stirring under reduced pressure after the substitution with nitrogen gas, from the viewpoints of preventing oxidation, decomposition, crosslinking reaction, and the like, and suppressing foaming. The liquid temperature at the time of ejecting the spinning dope is preferably in the range of 50 to 150 ℃, and the dope is not gelled, decomposed or colored.
When the polyvinyl alcohol fiber contains only the modified polyvinyl alcohol, the solvent is used to adjust the spinning dope of the modified polyvinyl alcohol. When the polyvinyl alcohol fiber contains the modified polyvinyl alcohol and the polyvinyl alcohol polymer (a), the modified polyvinyl alcohol and the polyvinyl alcohol polymer (a) may be mixed in advance at the time of adjusting the spinning dope, and the solvent may be used as the spinning dope, or the liquids containing the modified polyvinyl alcohol and the polyvinyl alcohol polymer (a) may be adjusted using the solvent, and then the liquids may be mixed to obtain the spinning dope.
When the polyvinyl alcohol fiber further contains the other polymer, either one or both of the modified polyvinyl alcohol and the polyvinyl alcohol polymer (a) may be mixed with the other polymer, or the other polymer may be dissolved in the solvent in advance for use.
The polyvinyl alcohol fiber can be produced by spinning the spinning dope adjusted as described above. The spinning method is not particularly limited, and examples thereof include a dry spinning method, a wet spinning method, and a dry-wet spinning method. Among them, it is preferable to spin by wet spinning or dry-wet spinning for the reason of high productivity, and the like, and to spray the curing liquid having curing ability for polyvinyl alcohol. Particularly, in the case of discharging the spinning dope from the multiple holes, the wet spinning method is preferable to the dry-wet spinning method from the viewpoint of preventing adhesion of fibers to each other at the time of discharge. The wet spinning method is a method of directly spraying a spinning dope from a spinning die to a solidifying bath, and the dry-wet spinning method is a method of temporarily spraying a spinning dope from a spinning die to air or an inert gas and then introducing the spinning dope into a solidifying bath. In the present invention, "solidification" means that the dope having fluidity is changed to a solid having no fluidity, and includes both gelation in which the dope composition is solidified without change and solidification in which the dope composition is solidified with change.
In the case where the solvent of the spinning dope is water, for example, a saturated aqueous sodium sulfate solution may be discharged as the curing liquid, and in the case where the solvent of the spinning dope is an organic solvent, for example, the spinning dope may be discharged into a curing bath mainly composed of alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, fatty acid esters such as methyl acetate and ethyl acetate, aromatic compounds such as benzene and toluene, or a mixture of two or more of these, namely, an organic solvent. In order to sufficiently solidify the inside of the fiber, a liquid in which a solvent of the spinning dope is mixed in a solidifying bath is preferably used. The mixing mass ratio of the solvents of the curing bath/spinning dope is preferably 95/5 to 40/60, more preferably 90/10 to 50/50, most preferably 85/15 to 55/45. In addition, by mixing the solvent of the spinning dope with the solidifying bath, the solidifying ability can be adjusted, and the cost of separating and recovering the solvent of the spinning dope from the solidifying bath can be reduced. The temperature of the curing bath is not limited, but in the case where the solvent of the spinning dope is an organic solvent, the curing is generally performed at a temperature of-15 to 30 ℃. The curing bath temperature is preferably-10 to 20 ℃, more preferably-5 to 15 ℃, and particularly preferably 0 to 10 ℃ from the viewpoints of uniform curing and energy saving. In the case where the temperature of the curing bath is outside this temperature range, the tensile strength of the obtained fiber sometimes decreases. In the case where the dope is heated to a high temperature, the solidifying bath is preferably cooled to keep the solidifying bath temperature low.
Next, the fibers separated from the curing bath are wet-stretched as needed. From the viewpoint of mechanical properties of the fiber and prevention of adhesion, it is preferable to perform wet stretching at a wet stretching ratio of 1.5 to 5 times, particularly 2.5 to 4 times, and in order to suppress adhesion of filaments, it is preferable to increase the wet stretching ratio within a range where fuzzing does not occur. In order to increase the wet drawing ratio, it is effective to divide the spinning dope described later into a plurality of stages of 2 stages or more in the extraction and removal step and to perform wet drawing.
In the case where the solvent of the spinning dope is an organic solvent, it is preferable to extract and remove the solvent of the spinning dope from the filaments by bringing the solvent into contact with an extraction bath mainly composed of an organic solvent having a solidifying ability. The wet stretching and the extraction may be performed in the same step. The extraction treatment can shorten the residence time in the extraction bath by allowing the pure solidification liquid to continuously flow in the countercurrent direction to the advancing direction of the filaments. This extraction treatment is preferable because the amount of the solvent of the spinning dope contained in the filaments can be 1% or less, particularly 0.1% or less by mass of the filaments. The contact time is 5 seconds or more, and particularly preferably 15 seconds or more. In order to increase the extraction speed and increase the extraction, it is preferable to loosen the filaments in the extraction bath. The solvent of the spinning dope is replaced with a solvent having a high solidifying ability for polyvinyl alcohol, for example, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, or a hydrophobic oil such as mineral oil, oxidized polyethylene, silicone, fluorine, is adhered in a solution or emulsion form, or is contracted to alleviate contraction stress during drying, which is also effective for preventing adhesion.
In the drying step, the fibers are dried preferably at 180 ℃ or lower, and further dry stretching can improve the mechanical properties of the fibers. The dry stretching conditions can be appropriately selected depending on the properties of the polyvinyl alcohol, in particular, the melting point or the desired water fusing temperature. The stretching ratio of the dry stretching after the drying step is preferably about 1.1 to 12 times, and the dry stretching temperature is preferably 160 to 220 ℃. The dry stretching temperature is preferably 160 to 240 ℃ from the viewpoint of process passability and effect of dry stretching, and more preferably 180 to 220 ℃ from the viewpoint of shrinkage in particular. From the viewpoint of suppressing the inter-fiber adhesion and efficiently stretching, it is preferable to perform the dry stretching in 6 or more stages, and it is particularly preferable to perform the multi-stage stretching at an elevated temperature.
The crystallinity of the polyvinyl alcohol fiber can be set within a desired range by performing heat treatment in the heat treatment step after the dry stretching. The temperature of the heat treatment is preferably 160 to 240 ℃. The heat treatment process and the dry stretching may be performed in the same process.
In the method for producing a polyvinyl alcohol fiber, in any one of the wet stretching, drying, dry stretching and heat treatment steps, the total stretching ratio in all the steps is set to 7 times or more at a temperature of 180 ℃. In any one of the steps of wet stretching, drying, dry stretching and heat treatment, stretching may be performed so that the total stretching ratio becomes 7 times or more.
Further, when the total stretching ratio is set to 7 times or more in any one of the wet stretching, drying, dry stretching and heat treatment, the stretching temperature may be set to 180 ℃ or more, and when the total stretching ratio is set to 7 times or more in any one of the wet stretching, dry stretching and heat treatment, the dry stretching temperature is preferably set to 180 ℃ or more, and the total stretching ratio is preferably set to 7 times or more in any one of the dry stretching and heat treatment from the viewpoint of improving the birefringence of the obtained polyvinyl alcohol fiber.
The total stretch ratio is preferably 7 times or more, more preferably 8 times or more, and still more preferably 9 times or more. The upper limit of the total draw ratio is not particularly limited, but is preferably set in a range where the obtained polyvinyl alcohol fiber does not generate fuzzing, and is usually 20 times or less.
Further, the stretching tension when the total stretching ratio is 7 times or more is preferably 0.40cN/dtex or more from the viewpoint of setting the birefringence of the obtained polyvinyl alcohol fiber to 0.040 or more, and more preferably 0.60cN/dtex or more from the viewpoint of further improving the birefringence. When the birefringence of the obtained polyvinyl alcohol fiber is 0.040 or more, the stretching tension is a stretching tension at which the total stretching ratio in all steps is 7 times or more in any one of the wet stretching, drying, dry stretching and heat treatment steps. The stretching tension in stretching when the total stretching magnification is not more than 7 times and in stretching after the total stretching magnification is more than 7 times is not necessarily the stretching tension.
The upper limit of the stretching tension is not particularly limited, but is preferably set in a range where the obtained fiber does not generate fuzzing, and is usually 2.0cN/dtex or less.
In the method for producing a polyvinyl alcohol fiber of the present invention, the polyvinyl alcohol fiber can be produced by setting the total draw ratio in all steps to 7 times or more at 180 ℃ or more and the draw tension at 180 ℃ or more at 7 times or more, more preferably, the dry draw temperature to 180 ℃ or more and the draw tension at 0.40cN/dtex or more at 180 ℃ or more in any one of the wet draw, dry draw and heat treatment steps.
That is, as an example of the method for producing the polyvinyl alcohol fiber,
The following production method is given: a spinning dope containing 5 to 30 mass% of a modified polyvinyl alcohol containing 1 mol% or more of carboxyl groups is wet-or dry-wet-spun in a curing bath mainly containing an organic solvent having curing ability for polyvinyl alcohol, and the total draw ratio in all the steps is set to 7 times or more at 180 ℃ and the draw tension in all the steps is set to 0.40cN/dtex or more at 180 ℃ or more in any of the steps of wet drawing, drying, dry drawing and heat treatment.
The polyvinyl alcohol fiber preferably has a high shrinkage and a high shrinkage stress when absorbing moisture at room temperature or more. Therefore, the shrinkage of the polyvinyl alcohol fiber at 35℃is preferably 55% or more, more preferably 60% or more, and still more preferably 65% or more.
The shrinkage and shrinkage stress at 35℃means the shrinkage and shrinkage stress when the polyvinyl alcohol fiber absorbs 35℃of water, and artificial urine obtained by adding urea to physiological saline is used as the water.
The shrinkage stress at 35℃is preferably 0.15cN/dtex or more, more preferably 0.2cN/dtex or more, and still more preferably 0.23cN/dtex or more.
The shrinkage of the polyvinyl alcohol fiber at 45℃is preferably 55% or more, more preferably 60% or more, and still more preferably 65% or more.
The shrinkage stress at 45℃is preferably 0.15cN/dtex or more, more preferably 0.2cN/dtex or more, and still more preferably 0.23cN/dtex or more.
The measurement was performed in the same manner as the measurement of the shrinkage rate and shrinkage stress at 45℃except that the temperature of the moisture was set to 45℃in the measurement of the shrinkage rate and shrinkage stress at 35 ℃.
The polyvinyl alcohol fiber rapidly shrinks when absorbing moisture at room temperature or higher, particularly around 35 ℃, and from the viewpoint of securing a flow path for moisture, the shrinkage rate after immersing in artificial urine at 35 ℃ for 30 seconds is preferably 25% or more, more preferably 40% or more.
From the viewpoint of preventing leakage after absorbing moisture, the shrinkage is preferably maintained, and the shrinkage after immersing in artificial urine at 35 ℃ for 60 seconds is preferably 30% or more, more preferably 45% or more.
The shrinkage rate 300 seconds after immersion in artificial urine at 35℃is preferably 40% or more, more preferably 55% or more.
Moreover, the shrinkage rate of 24 hours after immersion in artificial urine at 35 ℃ is preferably maintained in the range of 90% to 110% of the shrinkage rate of 300 seconds.
When the polyvinyl alcohol fiber is used as a part of an absorbent body, the obtained absorbent body is preferably excellent in water absorption and water retention. Therefore, the water absorption capacity of the polyvinyl alcohol fiber after 10 minutes of immersion is preferably 4 times or more, more preferably 6 times or more. The water absorption capacity after 1 hour of immersion is preferably 5 times or more, more preferably 6 times or more.
The dissolution rate is preferably 5% or less, more preferably 3% or less, from the viewpoints of water retention and shrinkage stress.
The water absorption capacity was obtained by immersing the polyvinyl alcohol fiber in a physiological saline solution at 35℃for a predetermined period of time, air-drying the polyvinyl alcohol fiber, measuring the mass of the polyvinyl alcohol fiber, and dividing the mass after immersion by the mass before immersion to obtain a value expressed as a percentage. The water absorption capacity after 1 hour of immersion was the absorption capacity after 1 hour of immersion.
The dissolution rate was a value obtained by measuring the mass of the polyvinyl alcohol fiber after drying at 120℃for 2.5 hours after measuring the absorption rate, and dividing the amount of change in mass before and after drying by the mass before drying by a percentage. In general, after drying, the mass decreases due to evaporation of moisture, and thus the dissolution rate is a decrease in absorbed moisture caused by drying. Therefore, the smaller the dissolution rate, the more excellent the water absorption and shrinkage stress.
When the present polyvinyl alcohol fiber is used for at least a part of a fiber structure to be described later, the present polyvinyl alcohol fiber is preferably water-soluble from the viewpoint of the fiber structure after disposal. Therefore, the melting temperature of the polyvinyl alcohol fiber in water is preferably 80 ℃ or lower, more preferably 60 ℃ or lower, from the viewpoint of water solubility.
The lower limit of the fusing temperature in water is not particularly limited, but may be room temperature or more.
The shrinkage, shrinkage stress, absorptivity and dissolution rate of the polyvinyl alcohol fiber can be controlled by the modification amount, saponification degree and crystallinity of the carboxyl group of the modified polyvinyl alcohol, the concentration of the stock solution in the production process of the polyvinyl alcohol fiber, the stretching temperature, the heat treatment temperature, and the stretching ratio in all the processes.
The tensile strength of the polyvinyl alcohol fiber is preferably 3cN/dtex or more, more preferably 4cN/dtex or more. The upper limit of the tensile strength is not particularly limited, but may be 25cN/dtex or less.
In the method for producing a polyvinyl alcohol fiber, the tensile strength of the polyvinyl alcohol fiber can be set to a desired tensile strength by controlling the stretching conditions such as the stretching temperature and the stretching ratio.
Further, other additives commonly used may be added to the present polyvinyl alcohol fiber. The additive amount is preferably 0.1 to 10 parts by mass based on 100 parts by mass of the total mass of the polyvinyl alcohol fiber.
The fineness of the single fibers of the polyvinyl alcohol fiber is not particularly limited, but fineness of about 0.1 to 1000dtex, particularly about 0.2 to 100dtex, and further about 0.5 to 10dtex can be widely used. The fiber length of the fiber may be appropriately set according to the application, but for example, in the case of processing into paper or textile yarns, the fiber length is preferably set to about 1 to 100 mm. The cross-sectional shape of the polyvinyl alcohol fiber is not limited, but from the viewpoints of water dispersibility, homogeneity of the product, etc., a simple substantially circular fiber is preferable as compared with a complicated shape.
The polyvinyl alcohol fiber is excellent in shrinkage and shrinkage stress when absorbing moisture at room temperature or more, particularly around 35 ℃, and can be used for applications such as moisture absorbers, moisture detection sensors, fishing gear fastening lines, plant grafting fastening lines, root wrapping fastening lines, and food fastening lines. Among them, the fiber structure is particularly preferably used for a moisture absorber. The form of the fibers used as the moisture absorber can be processed into filaments, staple fibers, spun yarns, ropes, woven fabrics, non-woven fabrics, ropes, and the like. The short fibers are used, for example, with a fiber length of 0.1 to 50 mm.
When the polyvinyl alcohol fiber is used as the moisture absorber, the content of the polyvinyl alcohol fiber of the invention in the moisture absorber is preferably 30% by mass or more, more preferably 50% by mass or more, and particularly preferably 70 to 100% by mass, based on 100% by mass of the total mass of the moisture absorber.
The water absorber can be used as a sanitary material, particularly, a liquid-absorbent sanitary material such as a disposable diaper or a physiological product, and among them, the water absorber can be preferably used for a disposable diaper. The form of use of the fibers is not particularly limited, but when the fibers are in the form of a rope or a nonwoven fabric, a remarkable effect can be obtained, and the fibers may be integrated with other fabrics such as a film, a woven fabric, or a nonwoven fabric to be used as a product, or the present polyvinyl alcohol fibers or a fiber structure using the present polyvinyl alcohol fibers may be used as a part of a product. From the viewpoint of obtaining the effect of exhibiting contractility, preventing leakage, and further improving the feeling of fitting to the body, a form of woven yarn or filament is preferably used as the string-like material. For example, by providing a string-like material made of the fibers of the present invention at the end portion of a paper diaper, the moisture absorption performance of the paper diaper can be improved, and leakage can be effectively suppressed.
The polyvinyl alcohol fiber can be used for applications other than the sanitary material, such as a moisture detection sensor, a fishing gear fastening wire, a plant grafting fastening rope, a root wrapping fastening rope, and a food fastening rope.
The method for producing the spun yarn is not particularly limited, but can be produced by a known method for producing a spun yarn, and examples thereof include ring spinning and tow spinning. From the viewpoint of effectively exhibiting the water-absorbent shrinkage property of the polyvinyl alcohol fiber, the thickness of the spun yarn is preferably about 1 to 20 british cotton counts.
In addition, when the polyvinyl alcohol fiber is used as a dry nonwoven fabric, excellent effects such as hand feeling, shrinkage performance, and stuffiness suppression can be obtained. The method for producing the nonwoven fabric is not particularly limited, but examples thereof include a needle punching method, a method of further heating a web formed by mixing heat-fusible fibers, and the like. From the viewpoint of effectively exhibiting the water-absorbent shrinkage performance of the polyvinyl alcohol fiber, it is preferable to use a nonwoven fabric produced without using a binder, and a needle-punched nonwoven fabric is preferable. The thickness of the nonwoven fabric is preferably about 0.5 to 3 mm.
The method for producing the fabric is not particularly limited, but from the viewpoints of hand feel, softness, and the like, a dry nonwoven fabric obtained by treating a web is preferable. As a method for producing a dry nonwoven fabric, for example, a method of opening filaments of polyvinyl alcohol fibers or the like by repulsive action of frictional electrification, or opening crimped or cut short fibers or the like by a carding machine or the like to form a web, and thermocompression bonding the web with a heat embossing roll at an area crimp ratio of 10 to 50%, particularly preferably 10 to 30%, that is, 10 to 50%, particularly preferably 10 to 30% of the surface area of the nonwoven fabric is preferable. By performing the thermocompression bonding treatment on a part of the nonwoven fabric, the mechanical properties and the morphological stability can be improved without impairing the feel, softness and water solubility of the nonwoven fabric. The area of each thermocompression bonding portion is preferably 4cm 2 or less, particularly preferably 2cm 2 or less, further preferably 1cm 2 or less, from the viewpoint of the feel, water solubility, and the like, and is preferably 1mm 2 or more from the viewpoint of the mechanical properties of the nonwoven fabric. The thermocompression bonding temperature is, for example, about 120 to 230 ℃ and the pressure is about 1 to 6 MPa. Further, since the polyvinyl alcohol fibers exhibit adhesion ability by the dry heat treatment, the mechanical properties of the nonwoven fabric can be efficiently improved by joining the fibers by the embossing treatment, and the nonwoven fabric can be easily molded into a desired shape by the thermocompression bonding treatment. For example, the molded article may be formed into a desired shape such as a bag shape or a box shape. As the packaging material, a bag-like material can be preferably used. For example, a pouch having one side of about 3 to 10cm may be formed.
Further, as another method for producing a dry nonwoven fabric, there is a method for producing a nonwoven fabric by entangling by needle punching. In this case, by using a known needle machine, conditions such as needle density, needle type, needle depth, and number of needle strokes are adjusted according to the shape of the fibers, and a dry nonwoven fabric excellent in strength and flexibility can be produced. Entanglement can be optimized by multiple needling machines as desired.
Examples
Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
The artificial urine and physiological saline used in the following measurement were as follows.
Artificial urine: urea in physiological saline was added at a concentration of 2 mass%.
Physiological saline: phosphate buffered saline at a concentration of 0.01 mol/L.
[ Degree of polymerization ]
The measured value of the limiting viscosity [ eta ] of the aqueous solution at 30℃according to JIS K6726 is calculated by the following formula (2). In addition, P is the average degree of polymerization of the polyvinyl alcohol.
logP＝1.613·log([η]×104/8.29) (2)
[ Saponification degree (mol%) ]
The measurement was performed in accordance with JIS K6726.
[ Fiber Strength (cN/dtex) ]
The measurement was performed in accordance with JIS L1013.
[ Birefringence index of polyvinyl alcohol fiber ]
The retardation was obtained by the Berek compensator method in a state where the sample was immersed in α -bromonaphthalene using a commercially available polarizing microscope and a sodium lamp as a light source, and was calculated.
[ Crystallinity (%) of polyvinyl alcohol fiber ]
The heat absorption amount DeltaH (J/g) in the endothermic peak when 10mg of the fiber sample was heated at a rate of 20 ℃/min under nitrogen was measured by using a differential scanning calorimeter (DSC-20) manufactured by Metretolidol, and the crystallinity was calculated from the ratio to the total heat of fusion of the polyvinyl alcohol, i.e., 174.5J/g, by the following formula (3).
Crystallinity (%) =Δh (J/g)/174.5 (J/g) ×100 (3)
[ Water fusing temperature of fiber (. Degree. C.) (Water WTb)
A fiber bundle having a length of 10cm was suspended in artificial urine at 2℃under a load of 2.2mg/dtex, the water temperature was raised at a rate of 2℃per minute, and the temperature at the time when the fiber was dissolved and the load was lowered was set as the in-water fusing temperature.
[ 35 ℃ Water absorption Rate of fiber ]
The fiber was precisely weighed, immersed in physiological saline at 35℃for 1 hour, allowed to stand for 10 minutes to remove the liquid, and the mass was measured. When the mass of the fiber before immersion in the physiological saline is a (g) and the mass after immersion is B (g), the water absorption capacity is calculated by the following formula (4).
Water absorption capacity (multiple) = (B)/(a) (4)
[ Dissolution Rate (%) of fiber ]
The fiber was precisely weighed, immersed in physiological saline at 35℃for 1 hour, allowed to stand for 10 minutes to remove the liquid, and the mass of the fiber after drying at 105℃for 4 hours was measured. When the mass of the fiber before impregnation in the physiological saline is a (g) and the mass after impregnation and drying is C (g), the dissolution rate is calculated by the following formula (5).
Dissolution rate (%) = [ (a) - (C) ]/(a) ×100 (5)
[ Shrinkage (%) of fiber at 35 ℃ ]
A fiber bundle having a length of 10cm was suspended in artificial urine at 2℃under a load of 2.2mg/dtex, the water temperature was raised at a rate of 2℃per minute, and the value obtained by dividing the original length by the length of the fiber at 35℃before the time when the fiber was dissolved and the load was lowered was taken as the shrinkage at 35 ℃.
[ Shrinkage stress at 35 ℃ of fiber (cN/dtex) ]
A fiber bundle having a length of 10cm was fixed at both ends with an initial load of 1/10g/dtex using a hand chuck for unit A, immersed in a water tank, and heated at a rate of 0.9 ℃/min, and stress at 35℃was measured using an Autograph-AG-IS/I/IC/EZGraph.
[ Shrinkage stress at 45 ℃ of fiber (cN/dtex) ]
A fiber bundle having a length of 10cm was fixed at both ends with an initial load of 1/10g/dtex using a hand chuck for unit A, immersed in a water tank, and heated at a rate of 0.9 ℃/min, and stress at 45℃was measured using an Autograph-AG-IS/I/IC/EZGraph.
[ Shrinkage (%) of fiber after 30 seconds ]
A10 cm length of the fiber bundle was suspended in 35℃physiological saline under a load of 0.15mg/dtex, and the shrinkage after 30 seconds was measured.
[ Shrinkage (%) of fiber after 60 seconds ]
A10 cm length of the fiber bundle was suspended in 35℃physiological saline under a load of 0.15mg/dtex, and the shrinkage after 60 seconds was measured.
[ Shrinkage (%) of fiber after 300 seconds ]
A10 cm length of the fiber bundle was suspended in 35℃physiological saline under a load of 0.15mg/dtex, and the shrinkage after 300 seconds was measured.
[ Shrinkage (%) of fiber after 24 hours ]
A10 cm length of the fiber bundle was suspended in 35℃physiological saline under a load of 0.15mg/dtex, and the shrinkage after 24 hours was measured.
[ Leakage-proof property of nonwoven Fabric sheet ]
The spun yarn having a shrinkage yarn British cotton count of 10 counts is obtained by a known method such as ring spinning or tow spinning. Next, a textile yarn of 200mm was sewn on both ends of a 300g/m 2 pulp sheet containing a water absorbent material. Then, artificial urine at 35℃was poured into a 20g pulp sheet and allowed to stand for 1 minute, and the leakage state of the urine thereafter was evaluated as "O" in the case of no leakage and as "X" in the case of leakage.
Example 1
Modified polyvinyl alcohol containing 5.2 mol% of acrylic groups (KURARAY co., ltd. Manufactured "Elvanol 80-18") as a copolymer with methyl acrylate containing a carboxyl group was dissolved in DMSO under stirring at 90 ℃ for 5 hours, thereby obtaining a spinning dope having a polyvinyl alcohol concentration of 22 mass%. The dope was wet-spun in a curing bath of 10 ℃ methanol/dmso=80/20 through a nozzle having a pore number of 40000 and a pore diameter of 0.08mm phi, and wet-heat stretching was performed 3.0 times in a methanol bath of 20 ℃. Next, DMSO in the filaments was extracted with methanol, and then a spin finish was applied, and dried at 140 ℃, and the obtained dried filaments were subjected to dry heat stretching under conditions of 180 ℃ and a dry heat stretching ratio of 3.3 times (total stretching ratio td=10 times). The tensile force at this time was 0.61cN/dtex. Next, the polyvinyl alcohol fiber was produced by dry heat shrinkage at 180℃under a dry heat shrinkage of 1%. The results of measuring the birefringence, crystallinity, in-water fusing temperature, water absorption capacity, dissolution rate, shrinkage stress, and leakage resistance of the nonwoven fabric sheet of the obtained fibers are shown in tables 1 and 2.
Example 2
Modified polyvinyl alcohol containing 2.5 mol% of methacrylic groups (KURARAY co., ltd. Manufactured "ElvanolT-25") as a copolymer with methyl methacrylate having a carboxyl group was dissolved in DMSO under stirring at 90 ℃ for 5 hours, thereby obtaining a spinning dope having a polyvinyl alcohol concentration of 20 mass%. The dope was wet-spun in a curing bath of 10 ℃ methanol/dmso=70/30 through a nozzle having a pore number of 35000 and a pore diameter of 0.08mm phi, and wet-heat stretching was performed 3.0 times in a methanol bath of 20 ℃. Next, DMSO in the filaments was extracted with methanol, and then a spin finish was applied, and dried at 140 ℃, and the obtained dried filaments were subjected to dry heat stretching under conditions of 180 ℃ and a dry heat stretching ratio of 3.3 times (total stretching ratio td=10 times). The tensile force at this time was 0.68cN/dtex. Next, the polyvinyl alcohol fiber was produced by dry heat shrinkage at 180℃under a dry heat shrinkage of 1%. The results of measuring the birefringence, crystallinity, in-water fusing temperature, water absorption capacity, dissolution rate, shrinkage stress, and leakage resistance of the nonwoven fabric sheet of the obtained fibers are shown in tables 1 and 2.
Example 3
Modified polyvinyl alcohol containing 2.5 mol% of methacrylic groups (KURARAY co., ltd. Manufactured "ElvanolT-25") as a copolymer with methyl methacrylate having a carboxyl group was dissolved in DMSO under stirring at 90 ℃ for 5 hours, thereby obtaining a spinning dope having a polyvinyl alcohol concentration of 20 mass%. The dope was wet-spun in a curing bath of 10 ℃ methanol/dmso=70/30 through a nozzle having a pore number of 35000 and a pore diameter of 0.08mm phi, and wet-heat stretching was performed 3.0 times in a methanol bath of 20 ℃. Next, DMSO in the filaments was extracted with methanol, and then a spin finish was applied, and dried at 140 ℃, and the obtained dried filaments were subjected to dry heat stretching at 200 ℃ under a dry heat stretching ratio of 4 times (total stretching ratio td=12 times). The tensile force at this time was 1.15cN/dtex. Next, the polyvinyl alcohol fiber was produced by dry heat shrinkage at 200℃under a dry heat shrinkage of 1%. The results of measuring the birefringence, crystallinity, in-water fusing temperature, water absorption capacity, dissolution rate, shrinkage stress, and leakage resistance of the nonwoven fabric sheet of the obtained fibers are shown in tables 1 and 2.
Example 4
Modified polyvinyl alcohol containing 1.8 mol% of methacrylic acid groups (KURARAY co., ltd. Manufactured "ElvanolT-66") as a copolymer with methyl methacrylate having a carboxyl group was dissolved in DMSO under stirring at 90 ℃ for 5 hours, thereby obtaining a spinning dope having a polyvinyl alcohol concentration of 20 mass%. The dope was wet-spun in a curing bath of 10 ℃ methanol/dmso=70/30 through a nozzle having a pore number of 35000 and a pore diameter of 0.08mm phi, and wet-heat stretching was performed 3.0 times in a methanol bath of 20 ℃. Next, DMSO in the filaments was extracted with methanol, and then a spin finish was applied, and dried at 140 ℃, and the obtained dried filaments were subjected to dry heat stretching under conditions of 190 ℃ and a dry heat stretching ratio of 3.0 times (total stretching ratio td=9 times). The tensile force at this time was 0.64cN/dtex. Next, the polyvinyl alcohol fiber was produced by dry heat shrinkage at 190℃under a dry heat shrinkage of 1%. The results of measuring the birefringence, crystallinity, in-water fusing temperature, water absorption capacity, dissolution rate, shrinkage stress, and leakage resistance of the nonwoven fabric sheet of the obtained fibers are shown in tables 1 and 2.
Example 5
Modified polyvinyl alcohol containing 1.5 mol% of itaconic acid group (KURARAY co., manufactured by ltd. As "KL-118") as a copolymer with itaconic acid containing a carboxyl group was dissolved in DMSO with stirring at 90 ℃ for 5 hours, thereby obtaining a dope having a polyvinyl alcohol concentration of 19 mass%. The dope was dry-wet spun in a solidifying bath of methanol/dmso=80/20 at 5 ℃ through a nozzle having a pore number of 80 and a pore diameter of 0.12mm phi, and wet-heat stretching was performed 3.0 times in a methanol bath at 20 ℃. Next, DMSO in the filaments was extracted with methanol, and then a spin finish was applied, and dried at 120 ℃, and the obtained dried filaments were subjected to dry heat stretching under conditions of 200 ℃ and a dry heat stretching ratio of 3.33 times (total stretching ratio td=10.0 times). The tensile force at this time was 0.69cN/dtex. Next, the polyvinyl alcohol fiber was produced by dry heat shrinkage at 200℃under a dry heat shrinkage of 1%. The results of measuring the birefringence, crystallinity, in-water fusing temperature, water absorption capacity, dissolution rate, shrinkage stress, and leakage resistance of the nonwoven fabric sheet of the obtained fibers are shown in tables 1 and 2.
Example 6
Modified polyvinyl alcohol containing 1.8 mol% of methacrylic acid groups (KURARAY co., ltd. Manufactured "ElvanolT-66") as a copolymer with methyl methacrylate having a carboxyl group was dissolved in DMSO under stirring at 90 ℃ for 5 hours, thereby obtaining a spinning dope having a polyvinyl alcohol concentration of 20 mass%. The dope was wet-spun in a curing bath of 10 ℃ methanol/dmso=70/30 through a nozzle having a pore number of 35000 and a pore diameter of 0.08mm phi, and wet-heat stretching was performed 2.5 times in a methanol bath of 20 ℃. Next, DMSO in the filaments was extracted with methanol, and then a spin finish was applied, and dried at 140 ℃, and the obtained dried filaments were subjected to dry heat stretching under conditions of 180 ℃ and a dry heat stretching ratio of 2.8 times (total stretching ratio td=7 times). The tensile force at this time was 0.43cN/dtex. Next, the polyvinyl alcohol fiber was produced by dry heat shrinkage at 180℃under a dry heat shrinkage of 1%. The results of measuring the birefringence, crystallinity, in-water fusing temperature, water absorption capacity, dissolution rate, shrinkage stress, and leakage resistance of the nonwoven fabric sheet of the obtained fibers are shown in tables 1 and 2.
Example 7
Modified polyvinyl alcohol (polymerization degree 1400) containing 3.0 mol% of acrylic group as a copolymer with methyl acrylate containing carboxyl group of acrylic group was dissolved in DMSO under stirring at 90 ℃ for 5 hours, thereby obtaining a spinning dope having a polyvinyl alcohol concentration of 21 mass%. The dope was dry-wet spun in a solidifying bath of methanol/dmso=80/20 at 5 ℃ through a nozzle having a pore number of 80 and a pore diameter of 0.12mm phi, and wet-heat stretching was performed 3.0 times in a methanol bath at 20 ℃. Next, DMSO in the filaments was extracted with methanol, and then a spin finish was applied, and dried at 120 ℃, and the obtained dried filaments were subjected to dry heat stretching under the conditions of 180 ℃ and a dry heat stretching ratio of 3.3 times (total stretching ratio td=10 times). The tensile force at this time was 0.75cN/dtex. Next, the polyvinyl alcohol fiber was produced by dry heat shrinkage at 180℃under a dry heat shrinkage of 1%. The results of measuring the birefringence, crystallinity, in-water fusing temperature, water absorption capacity, dissolution rate, shrinkage stress, and leakage resistance of the nonwoven fabric sheet of the obtained fibers are shown in tables 1 and 2.
Comparative example 1
Modified polyvinyl alcohol containing 5.2 mol% of acrylic groups (KURARAY co., ltd. Manufactured "Elvanol 80-18") as a copolymer with methyl acrylate containing a carboxyl group was dissolved in DMSO under stirring at 90 ℃ for 5 hours, thereby obtaining a spinning dope having a polyvinyl alcohol concentration of 22 mass%. The dope was wet-spun in a curing bath of 10 ℃ methanol/dmso=80/20 through a nozzle having a pore number of 40000 and a pore diameter of 0.08mm phi, and wet-heat stretching was performed 2.5 times in a methanol bath of 20 ℃. Next, DMSO in the filaments was extracted with methanol, and then a spin finish was applied, and dried at 140 ℃, and the obtained dried filaments were subjected to dry heat stretching under conditions of 180 ℃ and a dry heat stretching ratio of 2.0 times (total stretching ratio td=5 times). The tensile force at this time was 0.31cN/dtex. Next, the polyvinyl alcohol fiber was produced by dry heat shrinkage at 180℃under a dry heat shrinkage of 1%. The results of measuring the birefringence, crystallinity, in-water fusing temperature, water absorption capacity, dissolution rate, shrinkage stress, and leakage resistance of the nonwoven fabric sheet of the obtained fibers are shown in tables 1 and 2.
Comparative example 2
Polyvinyl alcohol (KURARAY co., ltd. Manufactured "27-96") containing no carboxyl group was dissolved in DMSO under stirring at 90 ℃ for 5 hours, thereby obtaining a spinning dope having a polyvinyl alcohol concentration of 21 mass%. The dope was wet-spun in a curing bath of 10 ℃ methanol/dmso=70/30 through a nozzle having a pore number of 40000 and a pore diameter of 0.08mm phi, and wet-heat stretching was performed 3.0 times in a methanol bath of 20 ℃. Next, DMSO in the filaments was extracted with methanol, and then a spin finish was applied, and dried at 165 ℃, and the obtained dried filaments were subjected to dry heat stretching under conditions of 203 ℃ and a dry heat stretching ratio of 2.7 times (total stretching ratio td=8.0 times). The tensile force at this time was 0.40cN/dtex. Next, the polyvinyl alcohol-based high shrinkage fiber was produced by dry heat shrinkage at 203℃under a dry heat shrinkage of 1%. The results of measuring the birefringence, crystallinity, in-water fusing temperature, water absorption capacity, dissolution rate, shrinkage stress, and leakage resistance of the nonwoven fabric sheet of the obtained fibers are shown in tables 1 and 2.
Comparative example 3
Modified polyvinyl alcohol containing 1.5 mol% of itaconic acid group (KURARAY co., manufactured by ltd. As "KL-118") as a copolymer of itaconic acid having a carboxyl group with itaconic acid group was dissolved in DMSO with stirring at 90 ℃ for 5 hours, thereby obtaining a spinning dope having a polyvinyl alcohol concentration of 20 mass%. The dope was dry-wet spun in a solidifying bath of methanol/dmso=80/20 at 5 ℃ through a nozzle having a pore number of 80 and a pore diameter of 0.12mm phi, and wet-heat stretching was performed 1.5 times in a methanol bath at 20 ℃. Next, DMSO in the filaments was extracted with methanol, and then a spin finish was applied, and dried at 120 ℃, and the obtained dried filaments were subjected to dry heat stretching under conditions of 190 ℃ and a dry heat stretching ratio of 3.67 times (total stretching ratio td=5.5 times). The tensile force at this time was 0.34cN/dtex. Next, the polyvinyl alcohol fiber was produced by dry heat shrinkage at 190℃under a dry heat shrinkage of 1%. The results of measuring the birefringence, crystallinity, in-water fusing temperature, water absorption capacity, dissolution rate, shrinkage stress, and leakage resistance of the nonwoven fabric sheet of the obtained fibers are shown in tables 1 and 2.
Comparative example 4
A modified polyvinyl alcohol (polymerization degree: 1600) containing 0.5 mol% of methacrylic acid groups, which was a copolymer with methyl methacrylate having a carboxyl group in methacrylic acid groups, was dissolved in DMSO at 90℃with stirring for 5 hours, thereby obtaining a dope having a polyvinyl alcohol concentration of 20 mass%. The dope was dry-wet spun in a solidifying bath of methanol/dmso=70/30 at 5 ℃ through a nozzle having a pore number of 80 and a pore diameter of 0.1mm phi, and wet-heat stretching was performed 3.0 times in a methanol bath at 20 ℃. Next, DMSO in the filaments was extracted with methanol, and then a spin finish was applied, and dried at 120 ℃, and the obtained dried filaments were subjected to dry heat stretching under the conditions of 180 ℃ and a dry heat stretching ratio of 3.3 times (total stretching ratio td=10 times). The tensile force at this time was 0.60cN/dtex. Next, the polyvinyl alcohol fiber was produced by dry heat shrinkage at 180℃under a dry heat shrinkage of 1%. The results of measuring the birefringence, crystallinity, in-water fusing temperature, water absorption capacity, dissolution rate, shrinkage stress, and leakage resistance of the nonwoven fabric sheet of the obtained fibers are shown in tables 1 and 2.
Comparative example 5
A modified polyvinyl alcohol (polymerization degree: 1600) containing 7.0 mol% of methacrylic acid groups, which was a copolymer with methyl methacrylate having a carboxyl group in methacrylic acid groups, was dissolved in DMSO at 90℃with stirring for 5 hours, thereby obtaining a dope having a polyvinyl alcohol concentration of 24 mass%. The dope was wet-spun in a solidifying bath of methanol/dmso=80/20 at 5 ℃ through a nozzle having a pore number of 80 and a pore diameter of 0.12mm phi, and wet-heat stretching was performed 3.0 times in a methanol bath at 20 ℃. Next, DMSO in the filaments was extracted with methanol, and then a spin finish was applied, and dried at 120 ℃, and the obtained dried filaments were subjected to dry heat stretching under the conditions of 180 ℃ and a dry heat stretching ratio of 3.3 times (total stretching ratio td=10 times). The tensile force at this time was 0.32cN/dtex. Next, the polyvinyl alcohol fiber was produced by dry heat shrinkage at 180℃under a dry heat shrinkage of 1%. The results of measuring the birefringence, crystallinity, in-water fusing temperature, water absorption capacity, dissolution rate, shrinkage stress, and leakage resistance of the nonwoven fabric sheet of the obtained fibers are shown in tables 1 and 2.
Watch (watch)
TABLE 2
As is clear from tables 1 and 2, the polyvinyl alcohol fibers containing the modified polyvinyl alcohol having 1 mol% or more of carboxyl groups and having a birefringence of 0.040 or more are excellent in shrinkage and shrinkage stress at 35 ℃.
For example, as shown in comparative examples 1,3 and 5, in the case of a polyvinyl alcohol fiber having a birefringence of less than 0.040, even if modified polyvinyl alcohol containing 1 mol% or more of carboxyl groups is contained, shrinkage and shrinkage stress are low, and leakage resistance in the case of producing a nonwoven fabric is poor. Moreover, the dissolution rate was also high, and the shrinkage stress was poor in the actual use area.
In comparative example 2, in which the birefringence is less than 0.040 and the modified polyvinyl alcohol containing carboxyl groups is not contained, the shrinkage and shrinkage stress are low, and the leak resistance in the case of producing a nonwoven fabric is poor.
In comparative example 4, which contains a modified polyvinyl alcohol having a carboxyl group content of less than 1 mol%, the shrinkage and shrinkage stress were low even when the birefringence was 0.040 or more, and the leakage-proof property was poor when a nonwoven fabric was produced.
Therefore, when the polyvinyl alcohol fiber is used as a moisture absorber, a flow path of moisture can be ensured and leakage of liquid can be prevented when moisture at room temperature or more, particularly at about 35 ℃.
Claims (8)
1. A polyvinyl alcohol fiber comprising a modified polyvinyl alcohol containing 1 mol% or more of carboxyl groups and having a birefringence of 0.040 or more.
2. The polyvinyl alcohol-based fiber according to claim 1, wherein,
The carboxyl group is included in at least one functional group selected from the group consisting of an acrylic group, a methacrylic group, and an itaconic group.
3. The polyvinyl alcohol-based fiber according to claim 1 or 2, wherein,
The crystallinity is 30% to 60%.
4. A fiber structure, at least a part of which comprises the polyvinyl alcohol fiber according to any one of claims 1 to 3.
5. The fiber structure according to claim 4, wherein,
The fiber structure body is non-woven fabrics or textile yarns.
6. A method for producing a polyvinyl alcohol fiber, wherein,
A spinning dope containing 5 to 30 mass% of a modified polyvinyl alcohol containing 1 mol% or more of carboxyl groups is wet-or dry-wet-spun in a curing bath mainly containing an organic solvent having a curing ability for polyvinyl alcohol, and the total draw ratio in all the steps is 7 times or more at a temperature of 180 ℃ or more in any one of wet drawing, drying, dry drawing and heat treatment.
7. The method for producing a polyvinyl alcohol fiber according to claim 6, wherein,
The total stretching ratio in all the steps is set to 7 times or more, and the stretching tension is set to 0.40cN/dtex or more.
8. The method for producing a polyvinyl alcohol fiber as claimed in claim 6 or 7, wherein,
The stretching temperature in the dry stretching step is 180 ℃ or higher.
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| JP2022014692 | 2022-02-02 | ||
| JP2022-014692 | 2022-02-02 | ||
| PCT/JP2023/003243 WO2023149481A1 (en) | 2022-02-02 | 2023-02-01 | Polyvinyl alcohol-based fiber, fiber structure, and method for producing same |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2656245B2 (en) | 1985-11-01 | 1997-09-24 | 株式会社クラレ | High speed shrink fiber and method for producing the same |
| JPH01168912A (en) * | 1987-12-25 | 1989-07-04 | Nichibi:Kk | Water absorbing shrinkable yarn of polyvinyl alcohol base and production thereof |
| JPH0314613A (en) * | 1989-06-07 | 1991-01-23 | Kuraray Co Ltd | High water-absorption fiber and its production |
| JPH03193910A (en) * | 1989-12-18 | 1991-08-23 | Toray Ind Inc | High-shrinkage polyvinyl alcohol fiber having excellent water resistance and production thereof |
| JP3558191B2 (en) * | 1996-07-25 | 2004-08-25 | 株式会社クラレ | Polyvinyl alcohol fiber and method for producing the same |
| JP2001262432A (en) | 2000-03-16 | 2001-09-26 | Kuraray Co Ltd | Water absorption shrinkable polyvinyl alcohol-based fiber |
| JP2004293022A (en) * | 2002-08-30 | 2004-10-21 | Kuraray Co Ltd | Highly water absorbing polyvinyl alcohol-based fiber and nonwoven fabric made of the same |
| CN112805420B (en) * | 2018-11-01 | 2024-02-06 | 株式会社可乐丽 | Polyvinyl alcohol fiber |
| JP7289233B2 (en) * | 2019-07-17 | 2023-06-09 | 株式会社クラレ | Polyvinyl alcohol fiber |
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