Basf Aktiengesellschaft

Hoechst Celanese Corporation

Thomas H Majette

Ulrich Riegel

Norbert Herfert

Volker Frenz

Guy T Woodrum

William E Volz

James Hill

Described is a water-absorbent composition containing from 30 to 100% by weight, based on the water-absorbent composition, of water-insoluble water-swellable hydrogels characterized by the following features:

Absorbent compositions

This invention is a method for converting fine particles of superabsorbent polymers into larger particles. The invention is primarily directed to aqueous solution processes for preparing superabsorbent polymers. In such aqueous solution polymerization methods, the polymerization reaction product is a high viscosity gel which is dried and ground into particles. In this grinding step, a portion of the product is produced as undesired fine particles having poor absorbency and poor fabrication properties; i.e. they 'gel block' and dust. According to the invention, fine superabsorbent polymer particles (up to about 3 parts) are mixed with the high viscosity reaction product gel (100 parts) containing about 20 parts by weight of superabsorbent polymer and water (5 parts per part of recycled particles) to form a mixture with improved rheological properties. The resulting mixture can be processed at a higher rate than a reaction product gel of equal solids content which results in a higher product yield and increased productivity.

Process for the conversion of fine superabsorbent polymer particles into

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Portsmouth, VA, United States of America

Thomas H Majette