Blue dye with particularly high purity and positive triboelectric control effect

US7621967B2 · kind B2 · utility

Assignee

• Clariant Produkte (Deutschland) GmbH · DE

Inventors

• Eduard Michel · Frankfurt, DE
• Ruediger Baur · Niedernhausen, DE
• Hans-Tobias Macholdt · Darmstadt, DE
• Norbert Kohl · Munster, DE

Key dates

• Filing date: Oct 21, 2003
• Grant date: Nov 24, 2009
• Expiry date: May 8, 2025

Classification

• Technology area (CPC G): Physics
• CPC primary: G03G9/0912
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

A dye base sulfate and method of making are described. The dye base sulphate of formula (I) is produced with a residual amine content of less than 2000 ppm, as determined by HPLC, by precipitation of the dye base, made by Friedel-Crafts alkylation, substitution and hydrolysis, as the dye base sulphate is a) taken up in water and subjected to a first steam distillation then filtered and optionally dried at 50 to 180° C., b) the pressed cake is treated with water or the optionally dried dye base sulphate is moistened with water, c) subjected to a further steam distillation and filtration and d) dried at 50 to 180° C.