Quinacridone quinone pigments

The exact physical properties of P.O.49, i.e., mainly the crystal modification of this quinacridone/quinacridone quinone pigment remain to be published. P.O.49, like P.R.209, is a specialty product for metallic shades. It is used to produce shades of gold in finishes, which are considerably more yellowish than those of P.O.48. 

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. 

A third yellow derivative, quinacridonequinone (XV), made as shown in Scheme V or directly from the oxidation of quinacridone, is also not weatherfast by itself. However, chemists at Du Pont found that solid solutions of the quinone with quinacridone leads to pigments with improved fastness properties (30-32). 

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