Process for preparing an aqueous polymer dispersion

US5756574A · kind A · utility

Assignee

• BASF SE

Inventors

• Roland Baumstark · Neustadt, DE
• Robert Rupaner · Ludwigshafen, DE

Key dates

• Filing date: Apr 3, 1997
• Grant date: May 26, 1998
• Expiry date: Apr 3, 2017

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08F6/006
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

A process for the preparation of an aqueous polymer emulsion, in which an aqueous emulsion of a polymer which contains at least one chemically bonded monomer having at least one ethylenically unsaturated group is produced in a manner known per se so that the total content of free monomers having at least one ethylenically unsaturated double bond, ie. monomers of this type which are not chemically bonded, in the aqueous polymer emulsion is from >0 to .ltoreq.1% by weight, based on the polymer content of the aqueous polymer emulsion, and this residual monomer content is then reduced by the action of a free radical redox initiator system comprising at least one oxidizing agent and at least one reducing agent, wherein the redox initiator system comprises, as the reducing agent, one which is present, in aqueous solution, in at least two tautomeric forms in equilibrium with one another (for example aminoiminomethanesulfinic acid and/or the salts thereof).