Process for the preparation of polyacetal copolymers

US5587449A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Dietrich Fleischer · Darmstadt, DE
• Michael Hoffmockel · Niedernhausen, DE
• Karl-Friedrich Muck · Wiesbaden, DE
• Gunter Sextro · Wiesbaden, DE

Key dates

• Filing date: Aug 31, 1995
• Grant date: Dec 24, 1996
• Expiry date: Aug 31, 2015

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G2/28
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

In the process for the preparation, with simultaneous end group stabilization, of polyacetal copolymers in a homogeneous phase and working up thereof, cyclic formaldehyde oligomers are copolymerized with cyclic acetals in the presence of an initiator in a polymerization reactor and immediately thereafter the initiator is deactivated by addition of basic substances, the unstable chain ends being degraded down to 0.01% to 1% in the presence of residual monomer, the product losing the majority of the residual monomer at the reactor outlet by letting down into a pelletizing device and the residual monomer which remains and the impurities dissolved in the product being removed by extraction with solvents and the product being pelletized, after drying and stabilization.