Patent · US Expired

Continuous polyamide extraction process

US6320021A · kind A · utility

6Cited by

11References

11Claims

0Family size

Assignee

BASF SE

Inventors

Peter Hildenbrand · Karlsruhe, DE
Reinhard Lang · Neustadt, DE
Alfons Ludwig · Ankum, DE
Gunter Pipper · Bad Dürkheim, DE

Key dates

Filing date	May 11, 2000
Grant date	Nov 20, 2001
Priority date	—
Expiry date	May 11, 2020

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC08G69/46
WIPO fieldMacromolecular chemistry, polymers
WIPO sectorChemistry

Abstract

A process for continuous extraction of polyamide particles in an essentially vertical extraction column using an aqueous extractant comprises using an extraction column that is divided into two zones and performing an extraction with a recirculating 15-40% strength by weight aqueous .epsilon.-caprolactam solution in the first zone and then with countercurrent water at a from 5 to 40.degree. C. lower temperature in the second zone. The process provides for economical extraction of polyamides with a low level of monomers and oligomers.

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