The manufacture of dioxazine pigments in a finely divided form

摘要

In an Example, (2), polyvinyl chloride is mixed with dioctyl phthalate and a dyestuff of the formula and, optionally, titanium dioxide and the mixture is gelatinized and rolled to give a violet, foil.ALSO:Dioxazine pigments are conditioned by grinding the damp or dry crude pigment with an organic liquid extractable with water until the desired particle size of the pigment is obtained and at least sufficient liquid is then removed to obtain the pigment in a pulverulent form. Organic liquids specified are methanol, ethanol, butanol, amyl alcohol, isopropanol, acetone, methyl ethyl ketone, diacetone alcohol, dioxane tetrahydrofurane, morpholine, pyridine, piperidine, diethylamine, formic acid and acetic acid. A dispersing agent may be present during grinding.