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:
Sep. 23, 1980
Filed:
Mar. 26, 1979
Hasso Hertel, Muhlheim am Main, DE;
Adolf Trampusch, Frankfurt am Main, DE;
Hoechst Aktiengesellschaft, , DE;
Abstract
By the present invention there has been found an improved process for the production of water-insoluble azo dyestuffs on the fiber according to the methods of the ice color dyeing, in which the fiber material is at first impregnated with a coupling component in an alkaline medium and thereafter developed by treating it with a developing bath which contains the diazonium compound; the improvement is characterized in that the developing bath contains an alkali metal-tri- or -tetrapolyphosphate and the pH value of the developing bath is greater than 4.5 prior to the coupling and smaller than 9 after the same. As compared with known processes, the novel process has the advantage that in this case there are not used any heavy metal salts, such as chromium and zinc salts, which have an adverse effect on the waste waters, and that besides there are no precipitates of zinc phosphate even in the case of zinc ions being present in the dye baths. The dyeings obtained with the novel process are marked by a good color yield, a good evenness and favorable fastness properties.