초록 ▼

Surface-treated superabsorbent polymer particles obtained by mixing 100 parts by weight of superabsorbent polymer particles with 0.001 to 10 parts by weight of a hydroxyalkylamide, and heating the surface-treated superabsorbent polymer particles to crosslink molecular chains existing at least in the

Surface-treated superabsorbent polymer particles obtained by mixing 100 parts by weight of superabsorbent polymer particles with 0.001 to 10 parts by weight of a hydroxyalkylamide, and heating the surface-treated superabsorbent polymer particles to crosslink molecular chains existing at least in the vicinity of the surfaces of the superabsorbent polymer particles is disclosed. Surface crosslinking the superabsorbent polymer particles with a hydroxyalkylamide substantially increases both the rate of liquid absorption and the quantity of liquid absorbed and retained by the superabsorbent particles.

대표청구항 ▼

1. Superabsorbent polymer particles comprising 100 parts by weight of a water-absorbing resin and about 0.001 to about 10 parts by weight of a hydroxyalkylamide, wherein the hydroxyalkylamide is present at surfaces of the water-absorbing resin and crosslinks polymer chains at the surfaces of the wat

1. Superabsorbent polymer particles comprising 100 parts by weight of a water-absorbing resin and about 0.001 to about 10 parts by weight of a hydroxyalkylamide, wherein the hydroxyalkylamide is present at surfaces of the water-absorbing resin and crosslinks polymer chains at the surfaces of the water-absorbing resin. 2. The particles of claim 1 wherein the particles contain about 0.01 to about 4 parts by weight of the hydroxyalkylamide, per 100 parts by weight of the water-absorbing resin. 3. The particles of claim 1 wherein the particles contain about 0.4 to about 2 parts by weight of the hydroxyalkylamide, per 100 parts by weight of the water-absorbing resin. 4. The particles of claim 1 wherein the hydroxyalkylamide has the structurewherein A is a bond, hydrogen, a monovalent or polyvalent organic radical selected from the group consisting of a saturated or unsaturated alkyl radical containing 1 to 60 carbon atoms, aryl, tri-C 1-4alkyleneamine, and an unsaturated radical containing one or more ethylenic groups; R1, selected independently, are hydrogen, straight or branched chain C1-5alkyl, or straight or branched chain C1-5hydroxyalkyl; R2, selected independently, are radicals selected from the group consisting of hydrogen and straight or branched C1-5alkyl, or the R2radicals are joined to form, together with carbon atoms, a cycloalkyl ring; p and p′, independently, are an integer 1 to 4; n is an integer having a value of 1 or 2, and n′ is an integer having a value of 0 to 2; or when n′ is 0, a polymer or copolymer, wherein n is greater than 1 formed from the hydroxyalkylamide when A is an unsaturated radical. 5. The particles of claim 4 wherein the hydroxyalkylamide has the structurewherein R 1is H or C1-5hydroxyalkyl, m is 0-8, and one of the R2radicals on the beta carbon is H and the other is H or a C1-5alkyl, and q and q′, independently, are an integer 1 to 3. 6. The particles of claim 4 wherein the hydroxyalkylamide has the structurewherein both R 2groups are H or both R2groups are —CH3. 7. The particles of claim 1 wherein the hydroxyalkylamide has the structurewhere R 3is a divalent radical selected from the group consisting of an alkylene radical containing 1 to 4 carbon atoms and arylene. 8. The particles of claim 1 wherein the hydroxyalkylamide is selected from the group consisting of bis[N,N-di(ß-hydroxyethyl)]adipamide, bis[N,N-di(ß-hydroxypropyl)]succinamide, bis[N,N-di(ß-hydroxyethyl)]azelamide, bis[N-N-di(ß-hydroxypropyl)]adipamide, bis[N-methyl-N-(ß-hydroxyethyl)]oxamide, and mixtures thereof. 9. The particles of claim 1 wherein the hydroxyalkylamide has the structure 10. The particles of claim 1 wherein the hydroxyalkylamide has the structure 11. The particles of claim 1 the hydroxyalkylamide has a structure L—A—L, wherein A is selected from the group consisting of (CH2)n, CH═CH, and CH2OCH2, L, independently, is selected from the group consisting of —C(═O)N(CH3)CH2CH2OH, —C(═O)NHCH2CH2OH, and —C(═O)N(CH2CH2OH)2, and n is 0, 1, 2, 3, or 4. 12. The particles of claim 11 wherein the hydroxyalkylamide is selected from the group consisting of bis[N-methyl-N-(ß-hydroxyethyl)]succinamide, bis[N-methyl-N-(ß-hydroxyethyl)]glutaramide, bis[N-methyl-N-(ß-hydroxyethyl)]succinamide/glutaramide, bis[N,N-(dihydroxyethyl)]succinamide, bis[N,N-(dihydroxyethyl)]glutaramide, bis[N,N-(dihydroxyethyl)]succinamide/glutaramide, bis[N,N-(dihydroxyethyl)]succinamide/glutaramide/adipamide, bis[N,N-(dihydroxyethyl)]glutaramide/adipamide, and mixtures thereof. 13. The particles of claim 11 wherein the hydroxyalkylamide comprises a reaction product of a reaction between (a) ethanolamine, diethanolamine, 2-(methylamino)ethanol, and mixtures thereof, and (b) a diethyl or a dimethyl ester of succinic acid, glutaric acid, malenic acid, oxalic acid, adipic acid, maleic acid, and mixtures thereof. 14. The particles of claim 1 wherein the water-absorbing resin comprises an a cidic water-absorbing resin. 15. The particles of claim 14 wherein the acidic water-absorbing resin is a neutralized, lightly crosslinked acrylic-type resin containing at least 10% acidic monomer units. 16. The particles of claim 15 wherein the acidic monomer units have a carboxylate, sulfonate, sulfate, or phosphate group. 17. The particles of claim 14 wherein the acidic monomer units are selected from the group consisting of acidic water-absorbing resin include acrylic acid, methacrylic acid, ethacrylic acid, α-chloroacrylic acid, α-cyanoacrylic acid, ß-methylacrylic acid, α-phenylacrylic acid, ß-acryloxypropionic acid, sorbic acid, α-chlorosorbic acid, angelic acid, cinnamic acid, p-chlorocinnamic acid, ß-stearylacrylic acid, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid, maleic acid, fumaric acid, tricarboxyethylene, 2-methyl-2-butene dicarboxylic acid, maleamic acid, N-phenyl maleamide, maleamide, maleic anhydride, fumaric anhydride, itaconic anhydride, citraconic anhydride, mesaconic anhydride, methyl itaconic anhydride, ethyl maleic anhydride, diethylmaleate, methylmaleate, maleic anhydride, vinylsulfonic acid, allyl sulfonic acid, vinyl toluene sulfonic acid, styrene sulfonic acid, an acrylic sulfonic acid, a methacrylic sulfonic acid, sulfoethyl acrylate, sulfoethyl methacrylate, sulfopropyl acrylate, 2-vinyl-4-ethylbenzene, 2-allylbenzene sulfonic acid, 1-phenylethylene sulfonic acid, sulfopropyl methacrylate, 2-hydroxy-3-methacryloxypropyl sulfonic acid, 2-acrylamide-2-methylpropane sulfonic acid, sulfated polyvinylalcohol, sulfated hydroxyethyl acrylate, sulfated hydroxypropyl methacrylate, methacryloxyethyl phosphate, and mixtures thereof. 18. The particles of claim 14 wherein the acidic water-absorbing resin is selected from the group consisting of a starch-acrylic acid graft copolymers, a saponified vinyl acetate-acrylic ester copolymer, a hydrolyzed acrylonitrile copolymer, a hydrolyzed acrylamide copolymer, an ethylene-maleic anhydride copolymer, an isobutylene-maleic anhydride copolymer, poly(vinylsulfonic acid), poly(vinylphosphonic acid), poly(vinylphosphoric acid), poly(vinylsulfuric acid), sulfonated polystyrene, poly(aspartic acid), poly(lactic acid), and mixtures thereof, neutralized 20 to 100 mole percent with a base. 19. The particles of claim 1 wherein the water-absorbing resin is polyacrylic acid neutralized 50 to 100 mole percent. 20. The particles of claim 1 wherein the water-absorbing resin comprises a basic water-absorbing resin. 21. The particles of claim 20 wherein the basic water-absorbing resin is a neutralized, lightly crosslinked resin containing at least 10% basic monomer units. 22. The particles of claim 20 wherein the basic water-absorbing resin is selected from the group consisting of a poly(vinylamine), a poly(alkylaminoalkyl (meth)acrylamide, a polyethylenimine, a poly(allylamine), a poly(allylguanidine), a poly(dimethylallylammonium hydroxide), a quaternized polystyrene, a guanidine-modified polystyrene, a quaternized poly(meth)acrylamide or ester analog thereof, a poly(vinylguanidine), and mixtures thereof. 23. The particles of claim 1 wherein the water-absorbing resin comprises a mixture of an acidic water-absorbing resin and a basic water-absorbing resin. 24. The particles of claim 1 wherein the water-absorbing resin comprises multicomponent superabsorbent polymer particles. 25. The particles of claim 1 having an absorption under a load of 0.7 psi after one hour of at least 20 grams of 0.9% saline per gram of particles. 26. The particles of claim 1 having an AUL at 0.7 psi of greater than 15 and a CRC of less than 32.4. 27. The particles of claim 1 having an AUL at 0.7 psi or greater than 20. 28. The particles of claim 27 having a CRC of less than 31.5. 29. Surface crosslinked superabsorbent polymer particles obtained by mixing 100 parts, by weight, of a superabsorbent polymer with about 0.001 to about 10 parts, by weight, of a hydroxyalkyl amide to form surface-treated superabsorbent polymer particles, then heating the surface-treated superabsorbent particles at about 90° C. to about 170° C. for about 60 to about 180 minutes to form surface crosslinks on the surface-treated superabsorbent polymer particles. 30. A method of preparing surface crosslinked superabsorbent polymer particles comprising: (a) providing 100 parts by weight of superabsorbent polymer particles; (b) forming a solution comprising about 0.5% to about 50% by weight of a hydroxyalkylamide in a solvent capable of solubilizing the hydroxyalkylamide; (c) applying the solution of (b) to surfaces of (a) to provide surface-treated superabsorbent polymer particles having about 0.001 to about 10 parts, by weight, of the hydroxyalkylamide per 100 parts, by weight, of superabsorbent polymer particles in the vicinity of the surfaces of the superabsorbent polymer particles; and (d) heating the surface-treated superabsorbent polymer particles at about 90° C. to about 170° C. for about 60 to about 180 minutes to form surface crosslinks in the vicinity of the surface of the superabsorbent polymer particles. 31. The method of claim 30 wherein step (c) is performed prior to step (d). 32. The method of claim 30 wherein steps (c) and (d) are performed simultaneously. 33. The method of claim 30 wherein the hydroxyalkylamide solution of step (b) further comprises a second surface crosslinking agent selected from the group consisting of a diol, a triol, a polyol, a divalent metal, a trivalent metal, a diglycidyl ether, a diamine, a halohydrin, a polyisocyanate, a dihaloalkane, a polyfunctional aziridine compound, a dialdehyde, a disulfonate ester, a diester, a multifunctional acid halide, an organic titanate, a melamine resin, a hydroxymethyl urea, and mixtures thereof. 34. The method of claim 33 wherein the second surface crosslinking agent comprises ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, ethylene glycol diglycidyl ether, and mixtures thereof. 35. The method of claim 30 wherein the hydroxyalkylamide solution of step (b) further comprises a second surface crosslinking agent capable of forming surface crosslinks on the superabsorbent polymer particles at a temperature of about 90° C. to about 160° C. 36. A method of preparing surface crosslinked superabsorbent polymer particles comprising: (a) polymerizing a mixture containing (i) unsaturated polymerizable monomers having acid groups or basic groups, and (ii) a polyfunctional crosslinking agent, dissolved in (iii) a solvent comprising water to form a superabsorbent polymer hydrogel; (b) adding a sufficient amount of a hydroxyalkylamide to the superabsorbent polymer hydrogel to provide about 0.001 to about 10 parts, by weight, of the ß-hydroxyalkylamide per 100 parts, by weight, of the superabsorbent polymer; and (c) heating the product of step (b) at about 90° C. to about 170° C. to dry the superabsorbent polymer hydrogel, form superabsorbent polymer particles, and form crosslinks on the surface of the superabsorbent polymer particles. 37. Surface crosslinked superabsorbent polymers prepared by the method of claim 36. 38. An article comprising the superabsorbent particles of claim 1. 39. The article of claim 38 wherein the article is a diaper or a catamenial device.