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:
Nov. 01, 1994
Filed:
Dec. 15, 1992
Oke Brauer, Walsrode, DE;
Bernd Haase, Walsrode, DE;
Dieter Herzog, Walsrode, DE;
Lutz Riechardt, Walsrode, DE;
Gerd Sonnenberg, Walsrode, DE;
Dietrich Tegtmeier, Bergisch-Gladbach, DE;
Wolff Walsrode AG, Walsrode, DE;
Abstract
The present invention relates to a process for producing methyl hydroxyalkyl cellulose ethers by alkalisation and etherification of celluloses, rinsing the methyl hydroxyalkyl cellulose ethers with water at higher temperatures and recovering the short-chain cellulose ethers that are soluble in the wash water, wherein the wash water containing sodium chloride and organic by-products is passed across a first stage of a membrane filtration having a molecular cut size of 200 to 150,000 Dalton, is concentrated during this process and passes across a second stage of a membrane filtration.