Preparation of a pigmentary form of perylene-3,4,9,10-tetracarboxylic acid diimide
AssigneeBASF SE
InventorsHelmut Hoch, Heinrich Hiller
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Abstract
A process for the preparation of pigmentary forms of perylene-3,4,9,10-tetracarboxylic acid diimide, wherein the diimide is converted to the leuco compound and the latter is oxidized in aqueous suspension, either with exposure to shearing forces in the presence of surfactants, or in the absence of shearing forces and in the presence of non-ionic surfactants, or of mixtures of non-ionic and anionic surfactants. The perylenetetracarboxylic acid diimide pigments give deep, brilliant and transparent full-shade colorations. In white reductions, they give distinctly reddish colorations.
Claims11
A process for the preparation of a pigmentary form of perylene-3,4,9,10-tetracarboxylic acid diimide, which gives brilliant, transparent and reddish colorations, wherein crude perylenetetracarboxylic acid diimide is formed into the leuco compound by reaction with an alkali metal dithionite in the presence of an alkali metal hydroxide and said leuco compound is then oxidized in an aqueous suspension either in the presence of a surfactant at from 20.degree. to 100.degree. C. or with exposure to shearing forces in the presence of a surfactant at from 20.degree. to 100.degree. C.
A process for the preparation of a pigmentary form of perylene-3,4,9,10-tetracarboxylic acid diimide, which gives brilliant, transparent and reddish colorations, wherein the crude perylenetetracarboxylic acid diimide is converted to the leuco compound and the latter is then oxidized in an aqueous suspension in the absence of shearing forces and in the presence of a non-ionic surfactant or of a mixture of a non-ionic and an anionic surfactant at from 40.degree. to 100.degree. C.
Dependencies are inferred from the claim text.