Patent ID: 7528214
Filing Date: 2009-05-05
Classification: C08G

Abstract:
1. A method for producing a transparent article, the method comprising the steps of: melt transesterifying a monomer mixture in the presence of a transesterification catalyst, said monomer mixture comprising a hydroquinone, at least one aromatic dihydroxy compound other than the hydroquinone, and a carbonic acid diester to produce a hydroquinone polycarbonate copolymer product comprising greater than 45 mole percent of structural units derived from the hydroquinone, wherein the transesterification catalyst is in an amount of 1×10 heating the hydroquinone polycarbonate copolymer product to a processing temperature of 5° C. to 20° C. above a maximum melting melt temperature for the hydroquinone polycarbonate copolymer product for a period of time effective to render the hydroquinone polycarbonate copolymer product transparent upon cooling to an ambient temperature; and cooling the hydroquinone polycarbonate copolymer product to the ambient temperature to produce the transparent article.