The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 06, 2001
Filed:
Nov. 29, 1999
Applicant:
Inventor:
Tohru Takekoshi, Scotia, NY (US);
Assignee:
General Electric Company, Schenectady, NY (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C08F 6/00 ;
U.S. Cl.
CPC ...
C08F 6/00 ;
Abstract
Polyethersulfones derived from dihydroxybiphenyls or dihydroxybenzenes, especially 4,4′-dihydroxybiphenyl, are isolated by crystallization from a solvent, preferably a water-immiscible aromatic solvent. Crystallization may be achieved by cooling from the reaction temperature to a temperature in the range of about 20-100° C., optionally with the use of a crystallization aid such as preformed polyethersulfone crystals. The crystallized polyethersulfone is then separated by filtration and by-product salts are removed therefrom by extraction with water.