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. 29, 1994
Filed:
Dec. 22, 1992
Erwin Dietz, Kelkheim, DE;
Adolf Kroh, Selters, DE;
Hoechst AG, Frankfurt am, DE;
Abstract
A process for the preparation of 2,9-dimethylquinacridone pigments or mixed crystal pigments or mixtures of 2,9-dimethylquinacridone and quinacridones which in the two outer fused benzene rings can be substituted, characterized by the form of their crystalline particles having an average ratio of length to width of <2:1 and an average particle size of <0.4 .mu.m, by adding to the solution of 2,9-dimethylquinacridone before or during the finishing of the corresponding crude quinacridones of the quinacridones mentioned in water or solvent mixtures at temperatures from about 60.degree. to about 200.degree. C., in each case a compound of the general formula (I) ##STR1## in an amount of about 1 to 20% by weight, in which Q is a quinacridone radical which is unsubstituted or substituted, Y is an --NR.sup.4 R.sup.5 group or the radical of a five-, six- or seven-membered heterocycle which contains one to three hetero atoms and can be substituted, R and R' are hydrogen or alkyl, and R.sup.1 to R.sup.5 are hydrogen and/or alkyl or alkylene, and n is a number from 1 to 4, the pigments themselves thus prepared and their use for the pigmenting of natural or synthetic materials and of lacquer systems.