High perylene pigments

P.R.206 is a mixed crystal type and consists of unsubstituted quinacridone and quinacridone quinone. The ratio between the two components as well as the crystal modification is not yet known. P.R.206 affords a very dull, yellowish shade of red, referred to as maroon. The pigment is considerably weaker than perylene pigments. All commercially available types of P.R.206 are more or less transparent and are used mostly in metallic finishes for automobiles, to which they lend reddish shades of copper. The pigment is often found to be difficult to disperse. The finishes frequently exhibit rheological problems, especially at high pigment concentration. 

The customary method of preparing perylene pigments is by reaction of perylene tetracarboxylic dianhydride with primary aliphatic or aromatic amines in a high boiling solvent. The dianhydride itself is also used as a pigment. Di-methylperylimide may also be obtained by treating the diimide with methyl chloride or dimethyl sulfate. 

Unsymmetrically substituted perylene pigments are a comparatively recent novelty. Selective protonation of the tetra sodium salt of perylene tetracarboxylic acid affords the monosodium salt of perylene tetracarboxylic monoanhydride in high yield. Stepwise reaction with amines produces unsymmetrically substituted perylene pigments [2],... 

Perylene pigments are derived from pentenecarboxylic acid, have high thermostability, but are difficult to disperse in PP (e.g. C.I. Pigment... 

The name perylene pigments refers to a class of high performance pigments made up of N,N -disubstituted perylene-3,4,9,10-tetracarboxylic acid imides or perylene-3,4,9,10-tetracarboxylic acid dianhydride. 

Because of their high opacity, THI pigments do not provide any advantage over azo condensation or perylene pigments for fiber applications. 

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