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:
Jul. 18, 1995
Filed:
Feb. 22, 1994
Suriyanarayanan Dorai, Hockessin, DE (US);
William W Goudie, Kennett Square, PA (US);
Sarah E Ochsenhirt, Cincinnati, OH (US);
Dhiren V Patel, Middletown, DE (US);
James R Cavall, Newark, DE (US);
E. I. du Pont de Nemours and Company, Wilmington, DE (US);
Abstract
Polyether glycols, especially poly(tetramethylene ether) glycols, having a narrow molecular weight distribution (e.g., Mw/Mn=1.2 to 1.80), are made by a process which consists of separating the low molecular weight fraction in an ultrafiltration module. In these units, molten PTMEG is fed at temperatures in the range of 30.degree. to 150.degree. C. and pressures ranging between 25 and 1500 psi. The PTMEG retentate from the ultrafiltration unit is also characterized by water content <25 ppm and low to negligible concentration of oligomeric cyclic ethers.