Basf Aktiengesellschaft

Ludwig Gall

Wolfgang Fabian

A new pigmentary form of perylene-3,4,9,10-tetracarboxylic acid diimide of the formula ##STR1## which has a specific surface area (measured by the BET method) of from 5 to 20 m.sup.2 /g and a maximum in the particle size distribution at from 0.2 to 1.mu. in length and from 0.1 to 0.4.mu. in width, the mean ratio of length to width being from 4:1 to 1:1, and the proportion of particles between these size limits being at least 50% of the total distribution. The pure shade of the new pigmentary from gives strongly yellowish red colorations which are very pure and very bright. The new pigment also has a good hiding power, which is from 2 to 3 times as great as that of the pigments of the prior art.

Perylene-3,4,9,10-tetracarboxylic acid diimide pigment, its manufacture

A new pigmentary form of perylene-3,4,9,10-tetracarboxylic acid diimide of the formula ##STR1## which has a specific surface area (measured by the BET method) of from 10 to 35 m.sup.2 /g and a maximum in the particle size distribution at from 0.1 to 0.5 .mu.m, the proportion of particles between these sizes being at least 50% of the total distribution and the mean ratio of length to width being from 3:1 to 1:1. The pure shade of the new pigmentary form gives strongly yellowish red colorations which are very pure and very bright. The new pigmentary form also has a good hiding power, which is from 2 to 3 times as great as that of the pigmentary forms of the prior art.

Growing community of inventors

Frankenthal, Germany

Ludwig Gall