Superabsorbent polymer having a capacity increase

May 12, 2014

US Patent No.: 8,647,317 B2
Inventor(s): Gonglu Tian, Greensboro, NC, US; David L. Bergman, Jr., Greensboro, NC, US; and Yaru Shi, Greensboro, NC, US.
Company: Evonik Stockhausen, LLC, Greensboro, NC, US.
Filed: 2/18/13
Issued: 2/11/14

A particulate superabsorbent polymer composition comprising a superabsorbent polymer comprising: a) at least one monomer selected from an ethylenically unsaturated carboxylic acid, ethylenically unsaturated carboxylic acid anhydride, salts or derivatives thereof based on the superabsorbent polymer; b) from about 0.001% by weight to about 5% by weight of a first internal crosslinking agent and second internal crosslinking agent, based on the monomer of a) wherein the first internal crosslinking agent comprises a silane compound comprising at least one vinyl group or allyl group and at least one Si—O bond wherein the vinyl group or allyl group is directly attached to a silicon atom; and c) a salt forming cation wherein the superabsorbent polymer has a degree of neutralization of greater than about 25%; wherein elements a), b) and c) are polymerized into a crosslinked hydrogel, which is then prepared into superabsorbent polymer particles; and the particulate superabsorbent polymer composition further comprises a surface coating comprising ethylene carbonate, aluminum sulfate and maleated polypropylene, wherein said particulate superabsorbent polymer composition has a Centrifuge Retention Capacity of from 25 g/g to about 55 g/g as set forth herein in the Centrifuge Retention Capacity Test.