Preparation of bead-form expandable styrene polymers

US5290819A · kind A · utility

Assignee

• BASF SE

Inventors

• Michael Witt · Ludwigshafen, DE
• Manfred Walter · Nuremberg, DE

Key dates

• Filing date: Jun 17, 1993
• Grant date: Mar 1, 1994
• Expiry date: Jun 17, 2013

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08J2325/06
• WIPO field: Other special machines
• WIPO sector: Mechanical engineering

Abstract

Bead-form expandable styrene polymers are obtained by suspension polymerization of styrene with addition of from 1 to 10% by weight of C.sub.3 - to C.sub.7 -hydrocarbons and/or carbon dioxide as blowing agent and, if desired, conventional additives, using, as suspension stabilizer, a mixture of magnesium pyrophosphate, a sulfonate group-containing extender and an alkali metal carboxylate or alkaline earth metal carboxylate, the magnesium pyrophosphate being prepared immediately before the polymerization by combining an aqueous solution of alkali metal pyrophosphate with at least the stoichiometrically necessary amount of a magnesium salt.