Abstract: 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.
Abstract: 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.
December 23, 1985
Date of Patent:
August 11, 1987
General Electric Company
Richard W. Howery, Niles R. Rosenquist, Robert A. Pyles, Patrick J. Mulvey