Surface-treated superabsorbent polymer particles
AssigneeBASK Aktiengesellschaft
InventorsDavid Eckert, Peter W. Carrico, Michael A. Mitchell
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Abstract
Surface-tested 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.
Claims34
Superabsorbent polymer particles comprising 100 parts by weight of a water-absorbing resin and about 0.01 to about 2 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.
Surface crosslinked superabsorbent polymer particles obtained by mixing 100 parts, by weight, of a superabsorbent polymer with about 0.2 to about 2 parts, by weight, of a hydroxyalkylamide 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.
A method of preparing surface crosslinked superabsorbent polymer particles comprising:
- (a) providing 100 parts by weight of super-absorbent 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 0.2 to about 2 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;
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- (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.
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 0.01 to about 2 parts, by weight, of the β-hydroxyalkylamide per 100 parts, by weight, of the superabsorbent polymer;
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- (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.
Dependencies are inferred from the claim text.