초록 ▼

An improved method of manufacturing surface-crosslinked superabsorbent polymer particles is disclosed. The superabsorbent polymer particles are surface crosslinked using about 20 to about 35 wt % of 1,3-propanediol as a cosolvent in a surface-crosslinking step. The use of 1,3-propanediol as a cosolv

An improved method of manufacturing surface-crosslinked superabsorbent polymer particles is disclosed. The superabsorbent polymer particles are surface crosslinked using about 20 to about 35 wt % of 1,3-propanediol as a cosolvent in a surface-crosslinking step. The use of 1,3-propanediol as a cosolvent reduces the amount of surface-crosslinking agent required to adequately surface crosslink the superabsorbent polymer, and reduces or eliminates the fouling of process equipment attributed to previous cosolvents used in a surface crosslinking step.

대표청구항 ▼

What is claimed is: 1. A method of surface cross-linking a superabsorbent polymer comprising the steps of: (a) providing superabsorbent polymer particles; (b) forming a surface-crosslinker composition comprising ethylene glycol diglycidyl ether, water, and 20 to 35 wt % of 1,3-propanediol as a coso

What is claimed is: 1. A method of surface cross-linking a superabsorbent polymer comprising the steps of: (a) providing superabsorbent polymer particles; (b) forming a surface-crosslinker composition comprising ethylene glycol diglycidyl ether, water, and 20 to 35 wt % of 1,3-propanediol as a cosolvent; (c) applying the solution of (b) to the surfaces of (a) to provide surface-treated superabsorbent polymer particles; and (d) heating the surface-treated superabsorbent polymer particles at 25�� C. to 150�� C. for 15 to 180 minutes to form surface crosslinks in the vicinity of the surface of the surface-treated superabsorbent polymer particles, wherein the amount of ethylene glycol diglycidyl ether in (b) is at least 5 wt % less than the ethylene glycol diglycidyl ether used when propylene glycol is a cosolvent to achieve a predetermined degree of surface crosslinking. 2. The method of claim 1 wherein step (c) is performed prior to step (d). 3. The method of claim 1 wherein steps (c) and (d) are performed simultaneously. 4. The method of claim 1 wherein the amount of ethylene glycol diglycidyl ether in (b) is at least 10 wt % less than the ethylene glycol diglycidyl ether used when propylene glycol is used as a cosolvent to achieve a predetermined degree of surface crosslinking. 5. The method of claim 1 wherein the amount of ethylene glycol diglycidyl ether in (b) is 5 wt % to 25 wt % less than the ethylene glycol diglycidyl ether used when propylene glycol is used as a cosolvent to achieve a predetermined degree of surface crosslinking. 6. The method of claim 1 wherein the surface-crosslinking solution comprises 25 to 30 wt % of the 1,3-propanediol. 7. The method of claim 1 wherein the surface-crosslinking solution is free of propylene glycol. 8. The method of claim 1 wherein the surface-crosslinker solution consists essentially of ethylene glycol diglycidyl ether, water, and 1,3-propanediol. 9. The method of claim 1 wherein the surface crosslinks are formed by essentially only the ethylene glycol diglycidyl ether. 10. The method of claim 1 wherein the superabsorbent polymer comprises a neutralized lightly crosslinked acrylic-type resin containing at least 10% acidic monomer units selected from the group consisting of a carboxylate, sulfonate, sulfate, and phosphate group. 11. The method of claim 1 wherein the superabsorbent polymer comprises polyacrylic acid neutralized 50 to 100 mole percent. 12. A surface-crosslinked superabsorbent polymer prepared by the method of claim 1.