Ciba Specialty Chemicals Corporation

Michael John Lemmons

Terence R Chamberlain

Donald Thomas DeRussy

A process for the manufacture of a pigments form of perylene-3,4,9,10-tetracarboxylic acid N,N'-bis-methylimide having a transparent clean yellowish shade, comprises comminution of a mixture comprising perylene-3,4,9,10-tetracarboxylic acid N,N&#x2032;-bis-methylimide produced by methylation of perylenetetracarboxylic imide with an alkylating agent and perylene-3,4,9,10-tetracarboxylic acid N,N&#x2032;-bis-methylimide produced by the condensation of perylenetetracarboxylic anhydride with methylamine, in the presence of dimerized rosin. The pigments obtainable are notable for their outstanding coloristic and rheological properties and are suitable for use in a variety of applications.

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Fort Thomas, KY, United States of America

Michael John Lemmons