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:
Mar. 25, 1997
Filed:
Sep. 14, 1995
Manfred Urban, Wiesbaden, DE;
Gerhard Wilker, M orfelden-Walldorf, DE;
Hoechst Aktiengescellschaft, , DE;
Abstract
A process for the preparation of 4,10-dibromoanthanthrone pigment, which comprises first subjecting the crude 4,10-dibromoanthanthrone pigment, which is in the coarsely crystalline state, to wet milling in an aqueous medium in a stirred ball mill which is operated at a power density of more than 2.5 kW per liter of milling space and at a peripheral stirrer speed of more than 12 m/s under the action of grinding media with a diameter of less than 1.0 mm, until the desired degree of fine division is reached (millbase suspension), and then isolating the resulting pigment in a conventional manner; or subjecting the prepigment obtained in the wet milling to a treatment at elevated temperature (finish) in an aqueous medium, an aqueous-organic medium or a liquid aromatic compound, and then isolating the pigment.