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. 30, 1993
Filed:
Jun. 17, 1992
Wolfgang Wernet, Kobe, JP;
Joseph Berger, Basle, CH;
Ciba-Geigy Corporation, Ardsley, NY (US);
Abstract
Mixtures of salts of organic dicarboxylic acids and organic compounds of non-salt character, dissolved in a C.sub.1 -C.sub.4 alkanol, can be concentrated or separated with a semipermeable membrane made from a copolyimide which contains a first aromatic diamine radical (1) and a second aromatic diamine radical (2) which carries --SO.sub.3 M groups, wherein M is H.sym., a mono-to trivalent metal cation or an ammonium cation. The first amine radical (1) and/or the second diamine radical (2) contains C.sub.1 -C.sub.4 alkyl groups in both o-positions to at least one amino group. These copolyamides are also radiation-sensitive (self-crosslinking) and can be used for the production of protective layers or relief images, development being carried out in an aqueous alkaline medium.