Patent · US Expired

Continuous process for removing unstable components from crude oxymethylene copolymer

US5144005A · kind A · utility

32Cited by

9References

13Claims

0Family size

Assignee

Hoechst GmbH · DE

Inventors

Gunter Sextro · Wiesbaden, DE
Karl-Friedrich Muck · Wiesbaden, DE
Karlheinz Burg
Eberhard Fischer · Königsee, DE

Key dates

Filing date	Feb 4, 1988
Grant date	Sep 1, 1992
Priority date	—
Expiry date	Feb 4, 2008

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC08G2/28
WIPO fieldMacromolecular chemistry, polymers
WIPO sectorChemistry

Abstract

Continuous process for removing unstable components from crude oxymethylene copolymer, which still contains catalysts, monomeric starting materials and unstable components, by treating the copolymer with deactivators, optionally in the presence of auxiliaries, in a pressure zone, and subsequently removing volatile components in a pressure-release zone in the presence or absence of stabilizers, in which process the crude polymer is fully melted in the absence of the deactivators and auxiliaries immediately after completion of the polymerization step, and the deactivators are subsequently incorporated, alone or together with auxiliaries, under pressure into the resultant polymer melt in at least one pressure zone. By this process, degradation is avoided and significantly better properties are obtained.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.