General Electric Company

Richard W Howery

Niles R Rosenquist

Robert Allen Pyles

James L Derudder

Patrick J Mulvey

A thermoplastic molding composition including at least one polycarbonate resin which is a polycarbonate homopolymer or copolymer; and an amount of at least one tetrahalobisphenol A copolymer effective to reduce the yellowness index of the at least one polycarbonate resin as determined after thermally molding the composition into an article. The article molded from the thermoplastic molding composition has a lower yellowness index than that of an article molded from a corresponding thermoplastic molding composition which does not contain any of the at least one tetrahalobisphenol A copolymer.

Color improved polycarbonate compositions and molded articles

A process for separating solid cyclic oligomeric dihydric phenol carbonate from solid high molecular weight linear aromatic polycarbonate which comprises admixing an organic solvent with a composition comprising major quantities of solid high molecular weight linear aromatic polycarbonate and minor quantities of solid cyclic oligomeric dihydric phenol carbonate and separating the cyclic oligomeric dihydric phenol carbonate soluble in the organic solvent from the high molecular weight linear aromatic polycarbonate insoluble in the organic solvent, said organic solvent selected so that a very large fraction of the said solid cyclic oligomer is separated from a very large fraction of the said polycarbonate which remains as a solid in the organic solvent.

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Mt. Vernon, IN, United States of America

Richard W Howery