Method for the production of N,N'-dialkyl perylene-3,4,9,10-tetracarboxylic acid diimides in a transparent pigment form

摘要

Preparation of N,N'-dimethyl-perylene-3,4,9,10-tetracarbodiimide (I) involves reacting the dianhydride (II) with NOTLESS 2 mole monomethylamine (III)/mole (II) and NOTLESS 3 times its mass of water at 50-200 degrees C and distilling off unreacted (III). The crude pigment is milled in liquid, aqueous (organic) medium at a power density of over 1.5 kW/l and stirrer peripheral velocity of over 12 m/s, using balls with a diameter 0.9 mm and the pigment is isolated. Pigment dispersant(s) and/or surfactant(s) are added at any time but at the latest during wet milling. In the preparation of N,N'-dimethyl-perylene-3,4,9,10-tetracarbodiimide (I) by reacting perylene-3,4,9,10-tetracarboxylic dianhydride (II) with monomethylamine (III), NOTLESS 2 mole (III)/mole (II) and at least 3 times the mass of water with respect to (II) are used. Reaction is carried out at 50-200 degrees C and unreacted (III) is distilled off. The resultant crude pigment is wet milled in a liquid, aqueous or aqueous-organic medium in a stirred ball mill with a power density of over 1.5 kW/l mill capacity and stirrer peripheral velocity of over 12 m/s, using balls with a diameter 0.9 mm and the resultant pigment is isolated. Additive(s) selected from pigment dispersants and surfactants are added at any time during the process but at the latest during wet milling.