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. 19, 1988
Filed:
Nov. 13, 1986
Ernst Spietschka, Idstein, DE;
Adolf Kroh, Selters, DE;
Hoechst Aktiengesellschaft, Frankfurt am Main, DE;
Abstract
A process for preparing the high-hiding form of the .gamma.-crystal modification of unsubstituted linear transquinacridone having improved tinctorial strength and producing a coating of higher gloss, which comprises carrying out (a) the known cyclization of 2,5-diphenylaminoterephthalic acid in highly concentrated polyphosphoric acid or in acid polyphosphoric acid ester to the quinacridone and/or (b) the known hydrolysis of the quinacridone melt obtained in (a) and/or (c) the known aqueous alkali extraction of the quinacridone obtained in (b) and/or (d) the known finishing of the quinacridone obtained in (a) in the presence of 0.5 to 10 percent by weight, based on quinacridone, of surface-active agents.