Sun Chemical Corporation

John Britanak

Brian L Thompson

Daphne J Rice

Edward H Sung

Mark W Johnson

Richard Kent Faubion

Wengan Wu

Tracie Tibbs

Zhijian Shen

Daphne Rice

A method for preparing a pigment composition for a plastics colorant is disclosed. The pigment composition is prepared by mixing a press cake of the pigment with a liquid containing a selected type of dispersant before the resulting slurry is dried. Thus prepared pigment composition has improved dispersibility in a thermoplastic or thermoset resin and greatly reduces the filter pressure rise in the molding systems for preparing masterbatches or various plastic compositions for molding, fiber, film and sheet.

Pigments with improved dispersibility

2,5-di(p-methoxyanilino)terephthalic acid crystal types I and II are made by controlling the pH during the recovery of the oxidized product of the condensation of dimethylsuccinyl succinate with p-methoxyaniline. The resulting 2,5-di(p-methoxyanilino)-terephthalic acid can be converted into 2,9-dimethoxyquinacridone or a solid solution thereof having controlled characteristics.

2,5-di(methoxyanilino) terephthalic acid polymorphs and quinacridones realized therefrom

Crude indanthrone is milled, with or without other additives, to reduce and normalize particle size and distribution to a sub-pigmentary, near amorphous, state. The resulting highly aggregated crude powder is then treated with a heterogeneous solvent system of water and an alkyl ester of an aromatic carboxylic acid, such as methyl benzoate, to de-aggregate and grow the particles back to a pigmentary size. The conditions of the solvent treatment can be controlled with respect to temperature, time, and solvent ratio such that the desired properties of strength, shade, and dispersability are optimized.

Conditioning method for indanthrone pigments

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Summerville, SC, United States of America

John Britanak