CN117247648A - Water-absorbent resin and method for producing same - Google Patents
Water-absorbent resin and method for producing same Download PDFInfo
- Publication number
- CN117247648A CN117247648A CN202210732265.5A CN202210732265A CN117247648A CN 117247648 A CN117247648 A CN 117247648A CN 202210732265 A CN202210732265 A CN 202210732265A CN 117247648 A CN117247648 A CN 117247648A
- Authority
- CN
- China
- Prior art keywords
- water
- absorbent resin
- segment
- polymer
- absorbent
- 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
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- 239000002250 absorbent Substances 0.000 title claims abstract description 160
- 229920005989 resin Polymers 0.000 title claims abstract description 131
- 239000011347 resin Substances 0.000 title claims abstract description 131
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 21
- 239000007788 liquid Substances 0.000 claims abstract description 48
- 238000006243 chemical reaction Methods 0.000 claims abstract description 30
- 239000002245 particle Substances 0.000 claims abstract description 29
- 239000003431 cross linking reagent Substances 0.000 claims abstract description 25
- 238000010526 radical polymerization reaction Methods 0.000 claims abstract description 20
- 238000004132 cross linking Methods 0.000 claims abstract description 17
- 239000011342 resin composition Substances 0.000 claims abstract description 12
- 229920013730 reactive polymer Polymers 0.000 claims abstract description 10
- -1 polyethylene chain Polymers 0.000 claims description 53
- 239000000178 monomer Substances 0.000 claims description 35
- 229920006226 ethylene-acrylic acid Polymers 0.000 claims description 30
- 229920000642 polymer Polymers 0.000 claims description 19
- 229920002125 Sokalan® Polymers 0.000 claims description 18
- 239000004584 polyacrylic acid Substances 0.000 claims description 18
- 239000004698 Polyethylene Substances 0.000 claims description 15
- 229920000573 polyethylene Polymers 0.000 claims description 15
- 230000014759 maintenance of location Effects 0.000 claims description 14
- 238000000034 method Methods 0.000 claims description 11
- 239000007864 aqueous solution Substances 0.000 claims description 10
- 239000003505 polymerization initiator Substances 0.000 claims description 9
- QHZOMAXECYYXGP-UHFFFAOYSA-N ethene;prop-2-enoic acid Chemical group C=C.OC(=O)C=C QHZOMAXECYYXGP-UHFFFAOYSA-N 0.000 claims description 7
- 238000012216 screening Methods 0.000 claims description 6
- 125000004435 hydrogen atom Chemical group [H]* 0.000 claims description 4
- 230000008569 process Effects 0.000 claims description 2
- 238000010521 absorption reaction Methods 0.000 description 29
- 239000000243 solution Substances 0.000 description 23
- 230000002745 absorbent Effects 0.000 description 22
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 20
- RTZKZFJDLAIYFH-UHFFFAOYSA-N ether Substances CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 16
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 15
- 230000000052 comparative effect Effects 0.000 description 14
- 239000006096 absorbing agent Substances 0.000 description 12
- 239000000499 gel Substances 0.000 description 11
- 230000000694 effects Effects 0.000 description 10
- 230000035699 permeability Effects 0.000 description 10
- 239000002253 acid Substances 0.000 description 9
- 239000011260 aqueous acid Substances 0.000 description 9
- 150000001875 compounds Chemical class 0.000 description 7
- 238000006116 polymerization reaction Methods 0.000 description 7
- 238000002360 preparation method Methods 0.000 description 7
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 6
- 239000002202 Polyethylene glycol Substances 0.000 description 6
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 6
- 239000003999 initiator Substances 0.000 description 6
- 238000002156 mixing Methods 0.000 description 6
- 238000006386 neutralization reaction Methods 0.000 description 6
- 230000000704 physical effect Effects 0.000 description 6
- 229920001223 polyethylene glycol Polymers 0.000 description 6
- FKNQFGJONOIPTF-UHFFFAOYSA-N Sodium cation Chemical compound [Na+] FKNQFGJONOIPTF-UHFFFAOYSA-N 0.000 description 5
- 238000001035 drying Methods 0.000 description 5
- 229920000831 ionic polymer Polymers 0.000 description 5
- 239000004745 nonwoven fabric Substances 0.000 description 5
- 235000011121 sodium hydroxide Nutrition 0.000 description 5
- 229910001415 sodium ion Inorganic materials 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 210000002700 urine Anatomy 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
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 4
- KUDUQBURMYMBIJ-UHFFFAOYSA-N 2-prop-2-enoyloxyethyl prop-2-enoate Chemical compound C=CC(=O)OCCOC(=O)C=C KUDUQBURMYMBIJ-UHFFFAOYSA-N 0.000 description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 4
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 4
- 239000000084 colloidal system Substances 0.000 description 4
- 239000000835 fiber Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 230000003472 neutralizing effect Effects 0.000 description 4
- 239000003960 organic solvent Substances 0.000 description 4
- 239000000047 product Substances 0.000 description 4
- 239000011780 sodium chloride Substances 0.000 description 4
- 229920003169 water-soluble polymer Polymers 0.000 description 4
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 3
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 3
- 125000003700 epoxy group Chemical group 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- ZIUHHBKFKCYYJD-UHFFFAOYSA-N n,n'-methylenebisacrylamide Chemical compound C=CC(=O)NCNC(=O)C=C ZIUHHBKFKCYYJD-UHFFFAOYSA-N 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 238000010298 pulverizing process Methods 0.000 description 3
- 150000003254 radicals Chemical class 0.000 description 3
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- 238000010998 test method Methods 0.000 description 3
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- UWFRVQVNYNPBEF-UHFFFAOYSA-N 1-(2,4-dimethylphenyl)propan-1-one Chemical compound CCC(=O)C1=CC=C(C)C=C1C UWFRVQVNYNPBEF-UHFFFAOYSA-N 0.000 description 2
- INQDDHNZXOAFFD-UHFFFAOYSA-N 2-[2-(2-prop-2-enoyloxyethoxy)ethoxy]ethyl prop-2-enoate Chemical compound C=CC(=O)OCCOCCOCCOC(=O)C=C INQDDHNZXOAFFD-UHFFFAOYSA-N 0.000 description 2
- SEFYJVFBMNOLBK-UHFFFAOYSA-N 2-[2-[2-(oxiran-2-ylmethoxy)ethoxy]ethoxymethyl]oxirane Chemical compound C1OC1COCCOCCOCC1CO1 SEFYJVFBMNOLBK-UHFFFAOYSA-N 0.000 description 2
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- VVJKKWFAADXIJK-UHFFFAOYSA-N Allylamine Chemical compound NCC=C VVJKKWFAADXIJK-UHFFFAOYSA-N 0.000 description 2
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 2
- FBPFZTCFMRRESA-FSIIMWSLSA-N D-Glucitol Natural products OC[C@H](O)[C@H](O)[C@@H](O)[C@H](O)CO FBPFZTCFMRRESA-FSIIMWSLSA-N 0.000 description 2
- 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 2
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- BAPJBEWLBFYGME-UHFFFAOYSA-N Methyl acrylate Chemical compound COC(=O)C=C BAPJBEWLBFYGME-UHFFFAOYSA-N 0.000 description 2
- FAIIFDPAEUKBEP-UHFFFAOYSA-N Nilvadipine Chemical compound COC(=O)C1=C(C#N)NC(C)=C(C(=O)OC(C)C)C1C1=CC=CC([N+]([O-])=O)=C1 FAIIFDPAEUKBEP-UHFFFAOYSA-N 0.000 description 2
- GLUUGHFHXGJENI-UHFFFAOYSA-N Piperazine Chemical compound C1CNCCN1 GLUUGHFHXGJENI-UHFFFAOYSA-N 0.000 description 2
- 239000004372 Polyvinyl alcohol Substances 0.000 description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 2
- 229920001131 Pulp (paper) Polymers 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 229920002472 Starch Polymers 0.000 description 2
- 229910052783 alkali metal Inorganic materials 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 125000004432 carbon atom Chemical group C* 0.000 description 2
- 150000001768 cations Chemical class 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- GPLRAVKSCUXZTP-UHFFFAOYSA-N diglycerol Chemical compound OCC(O)COCC(O)CO GPLRAVKSCUXZTP-UHFFFAOYSA-N 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- STVZJERGLQHEKB-UHFFFAOYSA-N ethylene glycol dimethacrylate Substances CC(=C)C(=O)OCCOC(=O)C(C)=C STVZJERGLQHEKB-UHFFFAOYSA-N 0.000 description 2
- 239000004088 foaming agent Substances 0.000 description 2
- 125000003010 ionic group Chemical group 0.000 description 2
- 229920000554 ionomer Polymers 0.000 description 2
- ZXEKIIBDNHEJCQ-UHFFFAOYSA-N isobutanol Chemical compound CC(C)CO ZXEKIIBDNHEJCQ-UHFFFAOYSA-N 0.000 description 2
- 229910052744 lithium Inorganic materials 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 239000011777 magnesium Substances 0.000 description 2
- FPYJFEHAWHCUMM-UHFFFAOYSA-N maleic anhydride Chemical compound O=C1OC(=O)C=C1 FPYJFEHAWHCUMM-UHFFFAOYSA-N 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 239000002504 physiological saline solution Substances 0.000 description 2
- 229920000768 polyamine Polymers 0.000 description 2
- 229920000223 polyglycerol Polymers 0.000 description 2
- 229920005862 polyol Polymers 0.000 description 2
- 150000003077 polyols Chemical class 0.000 description 2
- 229920002451 polyvinyl alcohol Polymers 0.000 description 2
- 229910052700 potassium Inorganic materials 0.000 description 2
- 239000011591 potassium Substances 0.000 description 2
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 2
- 229910052708 sodium Inorganic materials 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- 239000000600 sorbitol Substances 0.000 description 2
- 239000008107 starch Substances 0.000 description 2
- 235000019698 starch Nutrition 0.000 description 2
- IMNIMPAHZVJRPE-UHFFFAOYSA-N triethylenediamine Chemical compound C1CN2CCN1CC2 IMNIMPAHZVJRPE-UHFFFAOYSA-N 0.000 description 2
- YFHICDDUDORKJB-UHFFFAOYSA-N trimethylene carbonate Chemical compound O=C1OCCCO1 YFHICDDUDORKJB-UHFFFAOYSA-N 0.000 description 2
- STGNLGBPLOVYMA-MAZDBSFSSA-N (E)-but-2-enedioic acid Chemical compound OC(=O)\C=C\C(O)=O.OC(=O)\C=C\C(O)=O STGNLGBPLOVYMA-MAZDBSFSSA-N 0.000 description 1
- ZZXUZKXVROWEIF-UHFFFAOYSA-N 1,2-butylene carbonate Chemical compound CCC1COC(=O)O1 ZZXUZKXVROWEIF-UHFFFAOYSA-N 0.000 description 1
- PQUXFUBNSYCQAL-UHFFFAOYSA-N 1-(2,3-difluorophenyl)ethanone Chemical compound CC(=O)C1=CC=CC(F)=C1F PQUXFUBNSYCQAL-UHFFFAOYSA-N 0.000 description 1
- DZSVIVLGBJKQAP-UHFFFAOYSA-N 1-(2-methyl-5-propan-2-ylcyclohex-2-en-1-yl)propan-1-one Chemical compound CCC(=O)C1CC(C(C)C)CC=C1C DZSVIVLGBJKQAP-UHFFFAOYSA-N 0.000 description 1
- NEBBLNDVSSWJLL-UHFFFAOYSA-N 2,3-bis(2-methylprop-2-enoyloxy)propyl 2-methylprop-2-enoate Chemical compound CC(=C)C(=O)OCC(OC(=O)C(C)=C)COC(=O)C(C)=C NEBBLNDVSSWJLL-UHFFFAOYSA-N 0.000 description 1
- AOBIOSPNXBMOAT-UHFFFAOYSA-N 2-[2-(oxiran-2-ylmethoxy)ethoxymethyl]oxirane Chemical compound C1OC1COCCOCC1CO1 AOBIOSPNXBMOAT-UHFFFAOYSA-N 0.000 description 1
- SBWOBTUYQXLKSS-UHFFFAOYSA-N 3-(2-methylprop-2-enoyloxy)propanoic acid Chemical compound CC(=C)C(=O)OCCC(O)=O SBWOBTUYQXLKSS-UHFFFAOYSA-N 0.000 description 1
- WHNPOQXWAMXPTA-UHFFFAOYSA-N 3-methylbut-2-enamide Chemical compound CC(C)=CC(N)=O WHNPOQXWAMXPTA-UHFFFAOYSA-N 0.000 description 1
- CYUZOYPRAQASLN-UHFFFAOYSA-N 3-prop-2-enoyloxypropanoic acid Chemical compound OC(=O)CCOC(=O)C=C CYUZOYPRAQASLN-UHFFFAOYSA-N 0.000 description 1
- LWLOKSXSAUHTJO-UHFFFAOYSA-N 4,5-dimethyl-1,3-dioxolan-2-one Chemical compound CC1OC(=O)OC1C LWLOKSXSAUHTJO-UHFFFAOYSA-N 0.000 description 1
- UHIIHYFGCONAHB-UHFFFAOYSA-N 4,6-dimethyl-1,3-dioxan-2-one Chemical compound CC1CC(C)OC(=O)O1 UHIIHYFGCONAHB-UHFFFAOYSA-N 0.000 description 1
- DBCAQXHNJOFNGC-UHFFFAOYSA-N 4-bromo-1,1,1-trifluorobutane Chemical compound FC(F)(F)CCCBr DBCAQXHNJOFNGC-UHFFFAOYSA-N 0.000 description 1
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 description 1
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- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- 239000004604 Blowing Agent Substances 0.000 description 1
- 229920003043 Cellulose fiber Polymers 0.000 description 1
- 229920000742 Cotton Polymers 0.000 description 1
- 239000004971 Cross linker Substances 0.000 description 1
- LCGLNKUTAGEVQW-UHFFFAOYSA-N Dimethyl ether Chemical compound COC LCGLNKUTAGEVQW-UHFFFAOYSA-N 0.000 description 1
- JIGUQPWFLRLWPJ-UHFFFAOYSA-N Ethyl acrylate Chemical compound CCOC(=O)C=C JIGUQPWFLRLWPJ-UHFFFAOYSA-N 0.000 description 1
- 239000001856 Ethyl cellulose Substances 0.000 description 1
- ZZSNKZQZMQGXPY-UHFFFAOYSA-N Ethyl cellulose Chemical compound CCOCC1OC(OC)C(OCC)C(OCC)C1OC1C(O)C(O)C(OC)C(CO)O1 ZZSNKZQZMQGXPY-UHFFFAOYSA-N 0.000 description 1
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 1
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 description 1
- 241001125831 Istiophoridae Species 0.000 description 1
- JLVVSXFLKOJNIY-UHFFFAOYSA-N Magnesium ion Chemical compound [Mg+2] JLVVSXFLKOJNIY-UHFFFAOYSA-N 0.000 description 1
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 description 1
- 229920000881 Modified starch Polymers 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- OFOBLEOULBTSOW-UHFFFAOYSA-N Propanedioic acid Natural products OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 1
- UIIMBOGNXHQVGW-DEQYMQKBSA-M Sodium bicarbonate-14C Chemical compound [Na+].O[14C]([O-])=O UIIMBOGNXHQVGW-DEQYMQKBSA-M 0.000 description 1
- DWAQJAXMDSEUJJ-UHFFFAOYSA-M Sodium bisulfite Chemical compound [Na+].OS([O-])=O DWAQJAXMDSEUJJ-UHFFFAOYSA-M 0.000 description 1
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- 150000001340 alkali metals Chemical class 0.000 description 1
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- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 1
- PWVIXLWCGVNTLB-UHFFFAOYSA-K aluminum 2,2-dihydroxyacetate Chemical compound [Al+3].OC(O)C([O-])=O.OC(O)C([O-])=O.OC(O)C([O-])=O PWVIXLWCGVNTLB-UHFFFAOYSA-K 0.000 description 1
- 125000003277 amino group Chemical group 0.000 description 1
- ROOXNKNUYICQNP-UHFFFAOYSA-N ammonium peroxydisulfate Substances [NH4+].[NH4+].[O-]S(=O)(=O)OOS([O-])(=O)=O ROOXNKNUYICQNP-UHFFFAOYSA-N 0.000 description 1
- VAZSKTXWXKYQJF-UHFFFAOYSA-N ammonium persulfate Chemical compound [NH4+].[NH4+].[O-]S(=O)OOS([O-])=O VAZSKTXWXKYQJF-UHFFFAOYSA-N 0.000 description 1
- 229910001870 ammonium persulfate Inorganic materials 0.000 description 1
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- LSXWFXONGKSEMY-UHFFFAOYSA-N di-tert-butyl peroxide Chemical compound CC(C)(C)OOC(C)(C)C LSXWFXONGKSEMY-UHFFFAOYSA-N 0.000 description 1
- 125000004386 diacrylate group Chemical group 0.000 description 1
- 125000004177 diethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- HGVHMIAKUYLQLL-UHFFFAOYSA-N ethene;propane-1,2,3-triol Chemical group C=C.OCC(O)CO HGVHMIAKUYLQLL-UHFFFAOYSA-N 0.000 description 1
- 229920001249 ethyl cellulose Polymers 0.000 description 1
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- 239000012467 final product Substances 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 238000009775 high-speed stirring Methods 0.000 description 1
- 229920001477 hydrophilic polymer Polymers 0.000 description 1
- 125000001165 hydrophobic group Chemical group 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 1
- 229920002521 macromolecule Polymers 0.000 description 1
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 1
- 239000000347 magnesium hydroxide Substances 0.000 description 1
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 1
- 229910001425 magnesium ion Inorganic materials 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
- 238000005259 measurement Methods 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- FQPSGWSUVKBHSU-UHFFFAOYSA-N methacrylamide Chemical compound CC(=C)C(N)=O FQPSGWSUVKBHSU-UHFFFAOYSA-N 0.000 description 1
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- 239000000203 mixture Substances 0.000 description 1
- 235000019426 modified starch Nutrition 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- OOUWNHAYYDNAOD-UHFFFAOYSA-N n-[(dimethylamino)methyl]prop-2-enamide Chemical class CN(C)CNC(=O)C=C OOUWNHAYYDNAOD-UHFFFAOYSA-N 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- PNJWIWWMYCMZRO-UHFFFAOYSA-N pent‐4‐en‐2‐one Natural products CC(=O)CC=C PNJWIWWMYCMZRO-UHFFFAOYSA-N 0.000 description 1
- 150000002978 peroxides Chemical class 0.000 description 1
- JRKICGRDRMAZLK-UHFFFAOYSA-L peroxydisulfate Chemical compound [O-]S(=O)(=O)OOS([O-])(=O)=O JRKICGRDRMAZLK-UHFFFAOYSA-L 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 229920002401 polyacrylamide Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 239000011736 potassium bicarbonate Substances 0.000 description 1
- 235000015497 potassium bicarbonate Nutrition 0.000 description 1
- 229910000028 potassium bicarbonate Inorganic materials 0.000 description 1
- 229910000027 potassium carbonate Inorganic materials 0.000 description 1
- 235000011181 potassium carbonates Nutrition 0.000 description 1
- TYJJADVDDVDEDZ-UHFFFAOYSA-M potassium hydrogencarbonate Chemical compound [K+].OC([O-])=O TYJJADVDDVDEDZ-UHFFFAOYSA-M 0.000 description 1
- 235000011118 potassium hydroxide Nutrition 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 1
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 description 1
- 239000012966 redox initiator Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229940047670 sodium acrylate Drugs 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 235000017550 sodium carbonate Nutrition 0.000 description 1
- 235000010267 sodium hydrogen sulphite Nutrition 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 150000005846 sugar alcohols Polymers 0.000 description 1
- 229920001169 thermoplastic Polymers 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
- ZIBGPFATKBEMQZ-UHFFFAOYSA-N triethylene glycol Chemical compound OCCOCCOCCO ZIBGPFATKBEMQZ-UHFFFAOYSA-N 0.000 description 1
- 229940096522 trimethylolpropane triacrylate Drugs 0.000 description 1
- 210000002268 wool Anatomy 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
- C08L33/02—Homopolymers or copolymers of acids; Metal or ammonium salts thereof
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/04—Acids; Metal salts or ammonium salts thereof
- C08F220/06—Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/30—Sulfur-, selenium- or tellurium-containing compounds
- C08K2003/3045—Sulfates
- C08K2003/3081—Aluminum sulfate
Abstract
The present invention provides a water-absorbent resin and a method for producing the same, which comprises subjecting a water-absorbent resin composition to a radical polymerization reaction to obtain a gel. The gel is crushed and screened to obtain water-absorbent resin particles. The water-absorbent resin particles are subjected to a surface crosslinking reaction with a surface crosslinking agent and a reactive polymer to obtain a water-absorbent resin. The water-absorbent resin has excellent liquid flow conductivity.
Description
Technical Field
The present invention relates to a water-absorbent resin and a method for producing the same, and more particularly, to a water-absorbent resin having a preferable liquid flow conductivity and a method for producing the same.
Background
The water-absorbent resin has wide applicability such as agricultural or horticultural water retention agents, dew condensation inhibitors in construction materials, materials for removing water from petroleum, outer water-proof coating agents in electric cables, personal hygiene products (e.g., paper diapers, feminine hygiene products, disposable wipes, etc.), and paper diapers are used as bulk materials.
The absorption properties of a diaper depend on the absorption rate, the absorption capacity and the dryness. In recent years, paper diapers have been aimed at thinning by reducing the amount of pulp (hydrophilic fibers) and increasing the amount of water-absorbent resin, so that thinning of paper diapers is achieved by increasing the proportion of water-absorbent resin in the absorbent structure of the paper diapers. However, the reduced amount of hydrophilic fiber results in a reduced water storage space in a short period of time, and the liquid penetration rate is slowed down, so that the liquid is not absorbed and leaks. In addition, the water-absorbent resin must have a high permeability to liquid in addition to a good absorption rate. If the permeability of the liquid is poor, the water-absorbent resin may clog the gaps between the particles when absorbing the liquid, and a colloid clogging phenomenon may be formed, which may cause the liquid to flow out of the absorber of the diaper, and further, the absorption performance of the diaper may be lowered.
Therefore, it is one of the important points in the current research in the art to improve the absorption rate and permeability of the water-absorbent resin. In the conventional method, polyvalent metal cations (polyvalent metal cation) may be used for surface modification or aluminum dihydroxyacetate may be used to enhance the liquid flow conductivity of the water-absorbent resin. It is also possible to use a thermoplastic polymer such as polyethylene or polypropylene in the heat treatment step or to add an azo compound containing an amino group as a foaming agent to an aqueous acid group-containing monomer solution to enhance the liquid permeability of the water-absorbent resin. In addition, the encapsulated foaming agent (encapsulated blowing agent) or the water-soluble alkoxysilane compound is added into the acid group-containing monomer aqueous solution, so that the prepared water-absorbent resin has better absorption rate or good colloid stability respectively. In addition, conventionally, the water-soluble polyvalent metal powder, the adhesive and the water-absorbent resin are mixed to improve the diffusivity and the liquid permeability of the water-absorbent resin after absorbing the liquid.
In addition, the existing water-absorbent resin is subjected to surface cross-linking treatment, and further bridging is carried out on the surface of the water-absorbent resin, so that the effects of improving the absorption rate, improving the colloid strength, improving the caking resistance, improving the liquid permeability and the like are achieved. For example, the conventional method comprises dispersing a water-absorbent resin and a crosslinking agent in an organic solvent to perform a surface crosslinking treatment; or mixing inorganic powder into the water-absorbent resin for crosslinking treatment; or adding a crosslinking agent and then treating with steam; or performing surface treatment by using an organic solvent, water and polyalcohol; or surface treatment with an organic solvent, water, or an ether compound. However, the conventional surface treatment method can improve the absorption rate and the water absorption capacity under pressure, but the retention of the water-absorbent resin may be greatly reduced, and the effect of practical application may be reduced.
In view of the above, there is a need for providing a water-absorbent resin and a method for producing the same, which can achieve both of an improvement in the liquid flow conductivity and the water absorption capacity under pressure of the water-absorbent resin, and which can maintain a high retention force.
Disclosure of Invention
In one aspect, the present invention provides a method for producing a water-absorbent resin, which comprises the step of improving the liquid flow conductivity of the water-absorbent resin by reacting a polymer with a surface crosslinking reaction.
Another aspect of the present invention provides a water-absorbent resin produced by the above aspect.
According to one aspect of the present invention, there is provided a method for producing a water-absorbent resin. The method comprises subjecting the water-absorbent resin composition to a radical polymerization reaction to obtain a gel. The water-absorbent resin composition comprises an aqueous unsaturated monomer solution, a polymerization initiator and a radical polymerization crosslinking agent. Then, pulverizing and screening the gel to obtain a plurality of water-absorbent resin particles; and subjecting the water-absorbent resin particles to a surface crosslinking reaction with a surface crosslinking agent and a reactive polymer to obtain the water-absorbent resin, wherein the reactive polymer comprises a polyethylene segment and a polyacrylic acid segment.
According to an embodiment of the present invention, the above-mentioned reactive polymer is an ethylene acrylic acid polymer comprising a polyethylene segment represented by the following formula (1) and a polyacrylic segment represented by the following formula (2),
wherein M is a hydrogen atom, a group IA element or a group IIA element; and is also provided with
The polyethylene segment is 80 to 99wt% and the polyacrylic segment is 1 to 20wt% based on 100wt% of the ethylene acrylic acid polymer.
According to an embodiment of the present invention, the weight of the polyacrylic acid segment is 8wt% to 20wt% based on 100wt% of the weight of the polyethylene segment in the reaction polymer.
According to an embodiment of the present invention, the amount of the reactive polymer added is 0.01 to 10% by weight based on 100% by weight of the water-absorbent resin particles.
According to another aspect of the present invention, there is provided a water-absorbent resin produced by the above method, and the water-absorbent resin has a T20 value of not more than 180 seconds.
According to an embodiment of the present invention, the water-absorbent resin has a liquid flow conductivity of not less than 30X 10 - 7 cm 3 -s/g。
According to an embodiment of the present invention, the retention force of the water-absorbent resin is more than 20g/g.
The water-absorbent resin and the manufacturing method thereof can achieve the effects of improving the liquid flow conductivity and the water absorption rate under pressure of the water-absorbent resin and simultaneously can maintain the higher retention force of the water-absorbent resin by the reaction polymer participating in the surface cross-linking reaction, so the water-absorbent resin has practical applicability.
Detailed Description
As used herein, "about", "near" or "substantially" generally means within 20 percent, or within 10 percent, or within 5 percent of the stated value or range.
In view of the foregoing, the present invention provides a water-absorbent resin and a method for producing the same, which can achieve the effect of improving the liquid flow conductivity and the water absorption capacity under pressure of the water-absorbent resin by the reaction of a polymer and a surface crosslinking reaction, and can maintain a high retention force of the water-absorbent resin, thereby achieving practical applicability.
The method for producing a water-absorbent resin according to the present invention comprises subjecting a water-absorbent resin composition to a radical polymerization reaction to obtain a gel. In some embodiments, the water-absorbent resin composition includes an aqueous unsaturated monomer solution, a polymerization initiator, and a free radical polymerization crosslinking agent.
In some embodiments, the aqueous solution of the unsaturated monomer in the water-absorbent resin composition includes an acid-based monomer having an unsaturated double bond, such as acrylic acid. In some embodiments, the aqueous unsaturated monomer solution may be methacrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, marlin acid (maleic acid), maleic anhydride, fumaric acid (fumaric acid), and fumaric anhydride. The aqueous unsaturated monomer solution may include, but is not limited to, one monomer, and two or more of the above-mentioned aqueous monomer solutions may be selected.
In some embodiments, the concentration of the aqueous unsaturated monomer solution may be, but is not limited to, 20wt% to 55wt%, preferably 30wt% to 45wt%. Generally, when the concentration of the aqueous acid-based monomer solution is 20wt% to 55wt%, the viscosity of the polymerized product is moderate, the mechanical processing is easy, and the reaction heat in the free radical polymerization reaction is easy to control.
In other embodiments, other hydrophilic monomers having unsaturated double bonds may be optionally added, such as acrylamide, methacrylamide, 2-carboxyethyl acrylate, 2-carboxyethyl methacrylate, methyl acrylate, ethyl acrylate, dimethylacrylamide, and chlorinated acrylamido trimethylamine. However, the amount of the hydrophilic monomer to be added is not to deteriorate the physical properties (e.g., retention and absorption rate) of the water-absorbent resin.
In some embodiments, the aqueous acid-based monomer solution may be polymerized directly; or the neutralization agent is utilized to carry out partial neutralization, so that the acid-based monomer aqueous solution becomes neutral or weak acid, and then the polymerization reaction is carried out. In such embodiments, the neutralizing agent comprises an alkali metal or alkaline earth metal group hydroxide or carbonate compound (e.g., sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate), an amine compound, and combinations thereof. In some embodiments, the neutralization concentration of the aqueous acid-based monomer solution is 45 mole% to 85 mole%. When the neutralization concentration of the acid-based monomer aqueous solution is in the above range, the acid-based monomer aqueous solution may have a pH value suitable for radical polymerization, and may reduce the damage caused by careless contact with the human body. It is added that the neutralization concentration described herein is defined as the ratio of the number of moles of the basic solution to the number of moles of the aqueous acid-based monomer solution, and can also be regarded as the percentage of the acid groups of the aqueous acid-based monomer solution that are neutralized.
In some embodiments, the aqueous acid-based monomer solution has a pH of not less than 5.5, preferably from 5.5 to 7.0, more preferably from 5.5 to 6.5. If the pH of the aqueous acid-based monomer solution is 5.5 to 7.0, a large amount of unreacted monomers are less likely to remain in the aqueous solution after polymerization, and the physical properties of the water-absorbent resin to be produced later are better and the absorption amount is larger.
In some embodiments, a water-soluble polymer may be optionally added to the water-absorbent resin composition to reduce the production cost. In some embodiments, the water-soluble polymer comprises partially or fully saponified polyvinyl alcohol, polyethylene glycol, polyacrylic acid, polyacrylamide, starch or starch derivatives (e.g., methylcellulose acrylate, ethylcellulose, etc.), preferably starch and partially or fully saponified polyvinyl alcohol, alone or in combination. In the foregoing examples, the molecular weight of the water-soluble polymer is not limited, and the amount of the water-soluble polymer to be added is usually 0 to 20% by weight, preferably 0 to 10% by weight, more preferably 0 to 5% by weight, based on the amount of the unsaturated monomer aqueous solution taken as 100% by weight, in order not to deteriorate the physical properties of the water-absorbent resin.
The prepolymerization starts with the decomposition of the polymerization initiator to generate radicals. In some embodiments, the polymerization initiator is suitably used in an amount of 0.001 to 10wt%, preferably 0.1 to 5wt%, based on 100wt% of the aqueous unsaturated monomer solution. If the amount of the polymerization initiator is within the above range, the rate of radical polymerization is appropriate, the economic efficiency is good, the heat of reaction is easily controlled, and the formation of gel-like solids due to excessive polymerization can be avoided.
In some embodiments, the polymerization initiator comprises a thermal decomposition type initiator, a redox type initiator, and combinations thereof. In some embodiments, the thermally decomposed initiator comprises a peroxide [ e.g., hydrogen peroxide, di-tert-butyl peroxide, a peroxy amide or persulfate (including ammonium and alkali metal salts) ] and an azo compound [ e.g., 2-azobis (2-amidinopropane) dihydrochloride, 2-azobis (N, N-dimethylene isobutyridine) dihydrochloride ]. In some embodiments, the redox initiator comprises an acidic sulfite, ascorbic acid, or a ferrous salt. The polymerization initiator is preferably used in combination with a thermal decomposition type initiator and a redox type initiator, which are first allowed to react to generate radicals, and when the radicals are transferred to the monomer, the progress of the polymerization is initiated, and a large amount of heat released from the polymerization increases the temperature of the reaction system. When the reaction system reaches a specific temperature, the decomposition of the thermal decomposition initiator can be further initiated to make the polymerization more complete, so that excessive unreacted monomers can be avoided.
The radical polymerization crosslinking agent in the water-absorbent resin composition can provide the water-absorbent resin composition with an appropriate degree of crosslinking, thereby improving the workability of the water-absorbent resin composition after the polymerization reaction. In some embodiments, the free radical polymerization crosslinking agent may be selected from compounds containing two or more unsaturated double bonds, such as N, N-bis (2-propenyl) amine, N, N-methydiacrylamide, N, N-methydrylene bisacrylamide, acrylic acid propylene ester, ethylene glycol diacrylate, polyethylene glycol diacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, glycerol trimethacrylate, glycerol ethylene oxide-added triacrylate or trimethacrylate, trimethylol propane triacrylate, N, N, N-tris (2-propenyl) amine, ethylene glycol diacrylate, polyoxyethylene glycerol triacrylate, diethyl polyoxyethylene glycerol triacrylate, triethylene glycol diacrylate, and the like. In some embodiments, the free radical polymerization crosslinking agent may be selected from compounds containing two or more epoxy groups, such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, diglycerol polyglycidyl ether, and the like. Two or more radical polymerization crosslinking agents may be used singly or in combination.
In some embodiments, the free radical polymerization crosslinker is present at 0.001wt% to 5wt%, preferably 0.01wt% to 3wt%, based on 100wt% aqueous acid-based monomer solution. If the amount of the radical polymerization crosslinking agent added is within the above-mentioned range, the aqueous polymer solution after the reaction has a moderate viscosity, is relatively easy to machine, and the subsequent water-absorbent resin obtained has a large absorption amount, i.e., the water-absorbent resin has a good performance.
In some embodiments, the radical polymerization reaction described above may be performed in a batch reaction vessel or a conveyor reactor.
In some embodiments, the gel may optionally be cut with a grinder to a particle size of no more than 20mm, preferably no more than 10mm, prior to the screening step. In some embodiments, the screening step first screens out gels having a particle size of less than 2.0mm, preferably 0.05mm to 1.50mm. The gel with the particle size of more than 2.0mm is returned to the reactor for re-shredding. The particle size is controlled within the above range to avoid the generation of higher amounts of fines in the back-end process, and to provide good thermal conductivity to avoid excessive residual monomer in the final product. Generally, the narrower the particle size distribution of the gel, the better the physical properties and the benefits of the subsequent drying process.
In some embodiments, the gel may optionally be subjected to a drying process prior to subsequent operations. In some embodiments, the drying process is performed at a temperature of 100 ℃ to 180 ℃. The drying process is carried out by utilizing the temperature range, so that the drying time can be effectively controlled, and the crosslinking degree can be effectively controlled, thereby avoiding a large amount of unreacted monomers from remaining.
Next, the method for producing the water-absorbent resin comprises pulverizing and screening the gel to obtain water-absorbent resin particles. In some embodiments, the particle diameter of the water-absorbent resin particles is selected to be 0.06mm to 1.00mm, preferably 0.10mm to 0.85mm. Controlling the particle diameter of the water-absorbent resin particles to the above-mentioned range can reduce the amount of fine powder of the finished product and can make the absorption performance of the water-absorbent resin better. Similarly, the narrower the particle size distribution of the water-absorbent resin, the better the physical properties.
Then, the water-absorbent resin particles, the surface cross-linking agent and the reaction polymer are subjected to a surface cross-linking reaction to obtain the water-absorbent resin. Because the water-absorbent resin is a hydrophilic polymer which is not dissolved, the inside of the resin has a uniform bridging structure, and further bridging is needed on the surface of the resin in order to improve the absorption rate, the colloid strength, the anti-caking property, the body permeability and other characteristics. The surface crosslinking reaction is performed by using a surface crosslinking agent having a functional group capable of reacting with an acid group. In addition, in order to further improve the liquid flow conductivity of the water-absorbent resin produced, the present invention adds a reactive polymer such as an ionic polymer (ionomer) to collectively perform a surface crosslinking reaction.
In some embodiments, the surface cross-linking agent includes a polyol, a polyamine, a compound having two or more epoxy groups, and an alkylene carbonate, where the polyol may be, for example, glycerol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, and propylene glycol; the polyamine may be, for example, ethylenediamine, diethylenediamine, and triethylenediamine; the epoxy group-containing compound may be, for example, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, and diglycerol polyglycidyl ether; alkylene carbonates can be, for example, ethylene glycol carbonate, 4-methyl-1, 3-dioxolan-2-one, 4, 5-dimethyl-1, 3-dioxolan-2-one, 4-dimethyl-1, 3-dioxolan-2-one, 4-ethyl-1, 3-dioxolan-2-one, 1, 3-dioxan-2-one, 4, 6-dimethyl-1, 3-dioxan-2-one and 1, 3-dioxan-2-one. The reaction may be carried out by mixing two or more surface crosslinking agents singly or in combination. In addition, the surface cross-linking agent can be directly added according to the selected surface cross-linking agent, or the surface cross-linking agent is firstly prepared into aqueous solution or hydrophilic organic solution and then added. Hydrophilic organic solvents include, but are not limited to, methanol, ethanol, propanol, isobutanol, acetone, methyl ether, diethyl ether, and the like.
In some embodiments, the surface cross-linking agent is added in an amount of 0.001 to 10wt%, preferably 0.005 to 5wt%, based on 100wt% of the water-absorbent resin particles. When the amount of the surface cross-linking agent added is within the above range, the surface of the water-absorbent resin can be provided with a bridging structure, thereby achieving a preferable absorption performance.
The water-absorbent resin and the reaction polymer are uniformly mixed to effectively achieve the effect of the invention, so that a mixing device with better mixing effect is needed. In some embodiments, the mixing device may be a V-type mixer, a column mixer, a high-speed stirring mixer, a screw mixer, a gas flow mixer, a double arm kneader, a double arm conical mixer, a ribbon mixer, a close-ended mixer, a pulverizing kneader, a rotating mixer, or a screw extruder.
The ionic polymer is a polymer comprising a repeating unit composed of ionic units in a macromolecule of electrically neutral repeating units, wherein the ionic groups are part of the actual polymer backbone. In some embodiments, the ionic group may be, for example, a carboxylic acid group. In such embodiments, the ionic polymer may be an ethylene-acrylic acid compound (EAA) comprising a polyethylene segment having the following formula (1) and a compound having a polyacrylic acid segment having the following formula (2),
wherein M is a hydrogen atom, a group IA element (e.g., lithium, sodium, or potassium), or a group IIA element (e.g., calcium or magnesium). In this example, the polyethylene segment is 80 to 99wt% and the polyacrylic segment is 1 to 20wt% based on 100wt% of the ethylene acrylic acid polymer.
In other embodiments, the ionic polymer may be an ethylene acrylic acid compound having the following formula (3):
wherein M is a hydrogen atom, a group IA element (e.g., lithium, sodium, or potassium), or a group IIA element (e.g., calcium or magnesium). In some embodiments, M is preferably a group IA element.
In some embodiments, the weight of the polyacrylic acid segment (i.e., formula (2)) is 8wt% to 20wt% in the ethylene acrylic acid compound, based on 100wt% of the weight of the polyethylene segment (i.e., formula (1)). In the ethylene acrylic acid compound, the polyethylene chain segment is a hydrophobic group, and the polyacrylic acid chain segment is a hydrophilic group, so that the ethylene acrylic acid compound is easier to absorb water. Therefore, if the polyethylene segment is too large (for example, the weight of the polyacrylic acid segment is less than 8 wt%), the absorption capacity of the water-absorbent resin is lowered; on the other hand, if the polyacrylic acid segment is too large (for example, the weight of the polyacrylic acid segment is more than 20 wt%), the ionic polymer itself absorbs moisture in the atmosphere to generate caking, and the mixing effect with the water-absorbent resin particles is poor, so that the desired effect of the present invention cannot be achieved.
In some embodiments, the reactive polymer is added in an amount of 0.01 to 10% by weight based on 100% by weight of the water-absorbent resin particles. When the amount of the reactive polymer to be added is within the above range, the effect of improving the absorption capacity (for example, the absorption capacity under pressure) of the water-absorbent resin can be effectively obtained.
In some embodiments where the ionomer is an ethylene acrylic acid compound, the surface cross-linking reaction described above comprises heat treating at a temperature of 150 ℃ to 210 ℃. The ethylene acrylic acid compound can be completely melted by heat treatment at the above temperature, and a water-absorbent resin having a good quality, that is, a water-absorbent resin having a good water-absorbing ability can be obtained.
As described above, the present invention can produce a water-absorbent resin which can have liquid flow conductivity (saline flow conductivity, SFC) which can be used for evaluating liquid permeability. When the water-absorbent resin has a good liquid permeability, the problems of rewet, poor dryness and leakage of the absorbent body can be reduced. The liquid flow conductivity means that the water-absorbent resin has liquid permeability under high pressure after absorbing liquid, and when a further liquid enters the absorber, the further liquid easily passes through the water-absorbent resin having absorbed the liquid and diffuses into the other water-absorbent resin having not absorbed the liquid. The water-absorbent resin of the present invention has a liquid flow conductivity of not less than 30X 10 -7 cm 3 S/g, preferably not less than 40X 10 -7 cm 3 -s/g。
Further, the water-absorbent resin should have a good retention force (Centrifuge Retention Capacity, CRC) and a water absorption capacity under pressure (absorption against pressure, AAP) to ensure that the water-absorbent resin is not damaged or the ability to absorb liquid is not affected by the pressure applied to the absorber from the outside after absorbing the liquid. In some embodiments, the retention force of the water-absorbent resin of the present invention is not less than 20g/g, preferably not less than 25g/g. In some embodiments, the water-absorbent resin of the present invention has a water absorption capacity under pressure of more than 15g/g, preferably more than 20g/g, more preferably more than 23g/g.
In addition, the ability of the dried water-absorbent resin to absorb a liquid when it is initially contacted with the liquid can be expressed as a T20 value. When the water-absorbent resin has a low T20 value, it means that the dried water-absorbent resin easily absorbs the liquid. The T20 value of the water-absorbent resin of the present invention is not more than 180 seconds, preferably not more than 160. Incidentally, the T20 value is defined as the time required for 1g of the water-absorbent resin to absorb 20g of physiological saline and 0.01% by weight of an aqueous alcohol ethoxylate having 12 to 14 carbon atoms under a pressure of 0.3 psi. In some embodiments, the T20 value of the water-absorbent resin of the present invention is less than 180 seconds, preferably less than 160 seconds. The water absorbent resin has a low T20 value and high liquid flow conductivity, can reduce the rewet amount of the absorber, and improves the dryness of the diaper.
The absorbent body is formed into a sheet-like absorbent body by using the water-absorbent resin and the hydrophilic fiber of the present invention. In practice, the absorbent body may be placed on a liquid impermeable Polyethylene (PE) film, and a liquid permeable nonwoven fabric may be used as the top sheet; or fixing the water absorbent resin to the pulp fiber material (air) and/or the nonwoven fabric. The pulp fibers may be comminuted wood pulp, cross-linked cellulose fibers, cotton, wool, vinyl acetate fibers, and the like. Generally, the content of the water-absorbent resin (or referred to as core concentration) in the absorbent is 20 to less than 100wt%, preferably 40 to less than 100wt%, more preferably 50 to less than 100wt%, based on 100wt% of the absorbent. The effect of the present invention can be more remarkably exhibited by using the water-absorbent resin having such a high core concentration. In general, the basis weight (weight per unit area) of the absorbent is 0.01g/cm 2 To 0.30g/cm 2 And the thickness of the absorber is not more than 30mm.
The following examples are given to illustrate the present invention and are not to be construed as limiting the invention, but rather to enable various changes and modifications to be made therein without departing from the spirit and scope of the invention.
Preparation of the reaction Polymer
Production example 1
1180g of ethylene acrylic acid compound (CAS No.9010-86-0, available from Aldrich-Sigma, containing 18wt% of polyacrylic acid segments), 118g of sodium hydroxide and 5g of pure water were mixed at 150℃for 30 minutes using a ten-thousand horsepower machine (Banbury mixer) to prepare an ethylene acrylic acid compound (A) having a sodium ion neutralization.
PREPARATION EXAMPLES 2 to 3
Production example 1 was repeated except that the ethylene acrylic acid compound of production example 2 contained 15wt% of a polyacrylic acid segment (CAS No.9010-77-9, available from Aldrich-Sigma, containing 15wt% of a polyacrylic acid segment); preparation example 3 an ethylene acrylic acid compound (B) having a neutralized sodium ion and an ethylene acrylic acid compound (C) having a neutralized magnesium ion were prepared, respectively, by substituting 172g of magnesium hydroxide for sodium hydroxide.
PREPARATION EXAMPLES 4 to 5
Production example 1 was repeated, except that an ethylene acrylic acid compound (ex Exxon) was used, in which production example 4 was Escor having 10wt% of a polyacrylic acid segment TM 5080, while preparation 5 is Escor containing 7.5wt% polyacrylic acid segment TM 5020 to obtain ethylene acrylic acid compounds (D) and (E) having a neutralizing sodium ion, respectively.
Preparation of Water absorbent resin
Example 1
503.12g of 48wt% aqueous sodium hydroxide solution was slowly charged into a 2000c.c. conical flask containing 621.03g of acrylic acid and 670.74g of water, the dropping ratio of sodium hydroxide/acrylic acid was in the range of 0.85 to 0.95 for 2 hours, and the temperature of the in-flask neutralization reaction system was maintained in the range of 15 to 40 ℃ to obtain an aqueous unsaturated monomer solution having a monomer concentration of 42wt%, wherein 70mol% of the acrylic acid was partially neutralized to sodium acrylate, and the pH was 5.69.
Next, 1.36g of N, N' -methylenebisacrylamide (radical polymerization crosslinking agent) was added to the aqueous unsaturated monomer solution, and the temperature was maintained at about 20 ℃. Then, 0.35g of hydrogen peroxide, 4.15g of sodium bisulfite and 4.15g of ammonium persulfate were added as polymerization initiators to carry out radical polymerization.
The gel obtained by the reaction is cut by a cutting pulverizer, and the gel with the particle size of less than 2mm diameter is screened. Then, the mixture was dried at 130℃for 2 hours. And then screening with a sieve having a fixed particle diameter of 0.1mm to 0.85mm to obtain water-absorbent resin particles.
Then, 200g of the water-absorbent resin particles obtained above were weighed, 2.5g of a surface cross-linking agent, which was an aqueous solution of ethylene glycol, aluminum sulfate and water mixed in a volume ratio of 1:0.5:2, and 0.1g of an ethylene acrylic acid compound (A) having a neutralizing sodium ion were added, and heat treatment was carried out at 160℃for 1 hour, and after cooling, the water-absorbent resin was obtained.
Examples 2 to 6
The water-absorbent resins of examples 2 to 6 were produced by using the similar process steps as in example 1. Except that the ethylene acrylic acid compound (A) of example 2 was used in an amount of 1.0g; example 3 was modified with 0.1g of ethylene acrylic acid compound (B); example 4 was modified with 0.1g of ethylene acrylic acid compound (C); example 5 was modified with 0.1g of ethylene acrylic acid compound (D); example 6 4.63g of polyethylene glycol 600-diacrylate (UM 82-080, manufactured by Nissan chemical Co., ltd.) was used as a radical polymerization crosslinking agent in place of N, N' -methylenebisacrylamide.
Comparative examples 1 to 6
The water-absorbent resins of comparative examples 1 to 6 were also produced by using the similar process steps as in example 1. Except that comparative example 1 used an unneutralized ethylene acrylic acid compound (CAS No.9010-86-0, available from Aldrich-Sigma, containing 18wt% polyacrylic acid segment) instead of the ethylene acrylic acid compound (A) having a neutralized sodium ion; comparative example 2 was prepared using 0.1g of ethylene acrylic acid compound (E); comparative example 3 without the addition of ethylene acrylic acid compound; comparative example 45 g of ethylene acrylic acid compound (E) was used; comparative example 5 was heat treated at 140 c; comparative example 6 was heat treated at a temperature of 250 c.
Evaluation method
To evaluate the properties of the water-absorbent resin of the present invention, the physical properties thereof were analyzed by the following test methods, and the following measurement conditions were carried out at room temperature of 23.+ -. 2 ℃ and relative air humidity of 45.+ -. 10% unless otherwise specified. The water-absorbent resin should be thoroughly mixed before analysis.
Holding force
Retention (Centrifuge Retention Capacity, CRC) was tested according to the test method specified ERT 441.3 (10) by the european nonwoven fabric institute (European Disposables and Nonwovens Association, EDANA). The retention test results of the water-absorbent resins are shown in Table 1.
Water absorption capacity under pressure
Water absorption under pressure (absorption against pressure, AAP) was tested according to EDANA specification ERT442.3 (10) and tested for 60 minutes at a pressure of 4.9kPa for 0.9% aqueous sodium chloride solution. The test results of the water absorption capacity under pressure of the water-absorbent resin are shown in Table 1.
Liquid flow conductivity
Liquid flow conductivity (saline flow conductivity, SFC, unit: 10) -7 cm 3 Sec/g) was measured and calculated according to the method described in U.S. patent No. 5,562,646, which measured the flow conductivity of a 0.118M aqueous sodium chloride solution at a pressure of 0.3psi after the water-absorbent resin was first placed in Jayco synthetic urine for 60 minutes. The flow conductivity of the water-absorbent resin is shown in Table 1.
T20 value
T20 value (in seconds) was measured and calculated according to the method described in U.S. Pat. No.9,285,302, which was based on the time required for 1g of the water-absorbent resin to absorb 20g of physiological saline and 0.01wt% of an aqueous alcohol ethoxylate having 12 to 14 carbon atoms at a pressure of 0.3 psi. The average results of the three replicates are shown in table 1.
TABLE 1
Preparation of absorbent body
10.0 g of a water-absorbent resin and 10.0 g of crushed wood pulp were mixed and molded using an absorber molding machine, and a 400 mesh (38 μm) metal mesh was formed, and the absorber area was 160 square centimeters (8 cm. Times.20 cm). The formed absorber is placed over a polyethylene film and then a nonwoven fabric is placed. Next, the absorbent body was pressed with a pressure of 18.39kPa (area 160 square centimeters, weight 30 kg) for 5 minutes, and the four sides were stuck with white glue, to obtain an absorbent body for test.
Examples 7 to 12 and comparative examples 6 to 10
Examples 7 to 12 the absorbent bodies prepared in the above-described manner with the water-absorbent resins of examples 1 to 6, respectively; comparative examples 7 to 12 absorbent bodies were prepared in the same manner as described above with respect to the water-absorbent resins of comparative examples 1 to 6, respectively. The basis weight and thickness of the absorber are shown in table 2.
Rewet performance of absorbent body
The lower the rewet (i.e., dryness) of the absorbent body, the better the urine resistance of the water-absorbent resin. The test method was to place a weight of 4.8kPa (area 160 square centimeters, weight 7.8 kg) on the absorbent bodies prepared in the above examples 7 to 12 and comparative examples 7 to 12, drop 180 ml of synthetic urine (Jayco synthetic urine described in U.S. patent publication No. 20040106745) at the center point 3 times (30 minutes each time interval), and remove the weight above the absorbent body after the addition for another 30 minutes. Then, 30 pieces of filter paper (8 cm. Times.20 cm) of which the total weight W1 was measured in advance were placed on the absorber, and immediately a weight of 4.8kPa was placed on the absorber for 5 minutes, so that the filter paper was made to absorb the permeated liquid. Then, the weight W2 of 30 sheets of filter paper was measured. The synthetic urine rewet of the absorber is (W2-W1). The test results are shown in Table 2.
TABLE 2
According to the above test results, in examples 1 to 6, water-absorbent resins having both higher liquid flow conductivity and lower T20 value can be obtained by using a specific amount of an ethylene acrylic acid compound having a neutralizing metal ion to participate in the surface crosslinking reaction, as compared with comparative examples 1 to 6. In other words, the water-absorbent resins of examples 1 to 6 were excellent not only in liquid flow conductivity but also in liquid diffusibility and conductivity in a dry state. Further, the absorbent bodies according to examples 7 to 12, that is, the absorbent bodies produced with the water-absorbent resins of examples 1 to 6, may have a liquid rewet amount of less than 3.0g, which is significantly lower than that of comparative examples 7 to 12, indicating that the dryness is also superior.
Therefore, according to the method for producing a water-absorbent resin of the present invention, the reaction polymer is used to participate in the surface crosslinking reaction of the water-absorbent resin particles, so that the liquid flow conductivity and the liquid diffusibility of the water-absorbent resin in a dry state can be effectively improved, and the high retention of the water-absorbent resin can be maintained, thereby achieving practical applicability.
While the present invention has been described with reference to several embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended that the invention be limited only by the terms of the appended claims.
Claims (7)
1. A method for producing a water-absorbent resin, comprising:
performing radical polymerization on a water-absorbent resin composition to obtain a gel, wherein the water-absorbent resin composition comprises an unsaturated monomer aqueous solution, a polymerization initiator and a radical polymerization crosslinking agent;
crushing and screening the gel to obtain a plurality of water-absorbent resin particles; and
the water-absorbent resin particles are subjected to surface crosslinking reaction with a surface crosslinking agent and a reaction polymer to obtain the water-absorbent resin, wherein the reaction polymer comprises a polyethylene chain segment and a polyacrylic acid chain segment.
2. The method according to claim 1, wherein the reactive polymer is an ethylene acrylic acid polymer comprising the polyethylene segment represented by the following formula (1) and the polyacrylic acid segment represented by the following formula (2),
wherein M is a hydrogen atom, a group IA element or a group IIA element; and is also provided with
The polyethylene segment is 80 to 99wt% and the polyacrylic segment is 1 to 20wt% based on 100wt% of the ethylene acrylic acid polymer.
3. The method according to claim 1, wherein the weight of the polyacrylic acid segment is 8 to 20% by weight based on 100% by weight of the polyethylene segment in the reaction polymer.
4. The method for producing a water-absorbent resin according to claim 1, wherein the amount of the reactive polymer added is 0.01 to 10% by weight based on 100% by weight of the water-absorbent resin particles.
5. A water-absorbent resin, characterized by being produced by the process for producing a water-absorbent resin according to any one of claims 1 to 4, wherein the T20 value of the water-absorbent resin is not more than 180 seconds.
6. The water-absorbent resin according to claim 5, wherein the water-absorbent resin has a liquid flow conductivity of not less than 30X 10 -7 cm 3 -s/g。
7. The water-absorbent resin according to claim 5, wherein the retention force of the water-absorbent resin is more than 20g/g.
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