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:
Apr. 24, 1990
Filed:
Mar. 29, 1989
Hartmut Behringer, Erftstadt, DE;
Heinrich Rehberg, Hurth, DE;
Hoechst Aktiengesellschaft, , DE;
Abstract
Azo Pigments are made by subjecting a diazo component to an azo coupling reaction with the equivalent quantity of a coupling component difficultly soluble at less than 65.degree. C. in the aqueous/acid and aqueous/neutral pH-ranges. More specifically, an aqueous/acid-solution of the diazo component is continuously mixed at a temperature of less than 65.degree. C. within a period of less than 1 minute with the aqueous/alkaline solution of the coupling component and a predetermined pH between 2 and 9 is established by controlling the flow of the mass streams of diazo component and coupling component; in this way a portion of the coupling component is caused to undergo immediate reaction to the azo pigment to be made whereas the balance portion of the coupling component simultaneously commences precipitating as finely crystalline reactive matter, which is reacted in a post-reaction phase with unreacted diazo component to give the azo pigment to be made.