Water-swellable hydrophilic polymers

US5684104A · kind A · utility

Assignee

• Cassella Aktiengesellschaft · DE

Inventors

• Rüdiger Funk · Niedernhausen, DE
• Fritz Engelhardt · Frankfurt am Main, DE
• Ulrich Riegel · Landstuhl, DE
• Michael Wessling · Maintal, DE

Key dates

• Filing date: Jul 18, 1996
• Grant date: Nov 4, 1997
• Expiry date: Jul 18, 2016

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08F251/00
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Method for avoiding network defects due to unwanted secondary reactions during the polymerization in water-swellable hydrophilic polymers which contain polymers prepared by free radical (co)polymerization of one or more hydrophilic monomers of the formula I ##STR1## wherein R.sup.1 is hydrogen, methyl or ethyl, R.sup.2 is the group --COOR.sup.4, the sulphonyl group, the phosphonyl group, the phosphonyl group-esterified by (C.sub.1 -C.sub.4)-alkanol or a group of the formula ##STR2## R.sup.3 is hydrogen, methyl, ethyl or the carboxyl group, R.sup.4 is hydrogen, amino or hydroxy-(C.sub.1 -C.sub.4)-alkyl and R.sup.5 is the sulphonyl group, the phosphonyl group or the carboxyl group, or grafting (co)polymerization of one or more hydrophilic monomers of the formula I onto a grafting base, using a free radical initiator which forms three or more free radical sites per molecule.