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. 28, 1989
Heinrich Rehberg, Bruhl, DE;
Hartmut Behringer, Erftstadt, 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/netural pH-ranges. More specifically, an aqueous/alkaline solution of the coupling component is continuously mixed in a first reaction step with an aqueous solution of acetic acid, boric acid, phosphoric acid, hydrochloric acid or sulfuric acid at a temperature lower than 65.degree. C. within a period of less than 1 minute, during which the coupling component commenences precipitating at least partially as reactive matter; next, the suspension obtained is continuously mixed, in a second reaction step immediately following the first reaction step, with an aqueous/acid solution of the diazo component at a temperature of less than 65.degree. C. within a period of less than 1 minute, and a predetermined pH between 2 and 9 is established by controlling the flow of the mass streams of diazo component and coupling component whereby a portion of the coupling component is caused to undergo immediate reaction to the azo pigment to be made; the balance portion of the coupling component is ultimately reacted in a postreaction phase with unreacted diazo component to the azo pigment to be made.