Bridged, water-soluble copolymers, their preparation and their use

US4981913A · kind A · utility

Assignee

• BASF SE

Inventors

• Dietmar Moench · Weinheim, DE
• Andreas Stange · Mannheim, DE
• Joerg Liebe · Bischofswerda, DE
• Heinrich Hartman · Schifferstadt, DE
• Franz Merger · Bischofswerda, DE
• Manfred Schwartz · Bischofswerda, DE

Key dates

• Filing date: Sep 20, 1989
• Grant date: Jan 1, 1991
• Expiry date: Sep 20, 2009

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08F2810/50
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Bridged, water-soluble copolymers are obtainable by PA1 (A) copolymerization of a monomer mixture of PA2 (a) from 50 to 99 mol % of acrylamide and/or methacrylamide, PA2 (b) from 50 to 1 mol % of a monoethylenically unsaturated monomer containing actual groups and PA2 (c) from 0 to 20 mol % of monomers which differ from (a) and (b), PA1 in the presence of a polymerization initiator under conditions such that the acetal groups of the monomers (b) undergo virtually no hydrolysis, PA1 (B) hydrolysis of the acetal groups of the monomers (b), present as copolymerized units in the copolymers (A), PA1 (C) condensation of the copolymers (B) containing aldehyde groups at a pH above 5, at most to a degree such that the resulting condensates are still water-soluble and PA1 (D) stopping of the condensation reaction by adding acid until the pH reaches 3 or less, and are used as paper stock additives in papermaking for increasing the wet strength of paper.