Abstract: Increasing the endcap level to a level greater than about 90% for Optical Quality (OQ) Melt Polycarbonate significantly reduces the as-molded static charge for injection molded parts for Optical Disc applications. The use of resins with higher endcap levels in combination with antistatic additives provides a highly robust formulation suitable for even the most demanding emerging formats as Digital Versatile Disc (DVD) and in all commercial Optical media molding machines. Thus, optical quality polycarbonates are prepared by performing a base-catalyzed polymerization of a diaryl carbonate and a dihydric phenol under conditions effective to produce a polycarbonate product having an endcap level of 90% or greater.

Abstract: Increasing the endcap level to a level greater than about 90% for Optical Quality (OQ) Melt Polycarbonate significantly reduces the as-molded static charge for injection molded parts for Optical Disc applications. The use of resins with higher endcap levels in combination with antistatic additives provides a highly robust formulation suitable for even the most demanding emerging formats as Digital Versatile Disc (DVD) and in all commercial Optical media molding machines. Thus, optical quality polycarbonates are prepared by performing a base-catalyzed polymerization of a diaryl carbonate and a dihydric phenol under conditions effective to produce a polycarbonate product having an endcap level of 90% or greater.

Abstract: Blow moldable polycarbonate is produced by first producing a polycarbonate preform by a melt transesterification process. The polycarbonate preform comprises 2.1 to 10 mole percent polyfunctional branching agent, based on the total moles of polycarbonate in the polycarbonate preform. The polycarbonate preform is then melt equilibrated with a second polycarbonate to produce a blow moldable grade.

Abstract: UV stabilized polycarbonates are provided having chemically combined polyhydric phenol benzotriazole carbonate units, such as 1,1-bis(4-hydroxyphenyl)-1-[4-hydroxy-3-(N-2-benzotriazole)phenyl]ethane carbonate units and methods for making. Incorporation of the polyhydric phenol benzotriazole functional units into the polycarbonate backbone can be achieved by redistribution or transesterification under melt polymerization conditions.

Abstract: The efficiency of a redistribution catalyst during polycarbonate redistribution is improved by employing an extruder screw design that provides a melt seal between the extruder throat and the vacuum port. A melt seal exists when the free volume within the extruder is sufficiently filled with molten resin so as to prevent the passage of gases between sections of the extruder.

Abstract: The present invention is directed to a method for effecting the redistribution of polycarbonate and polycarbonate blends utilizing a tetraorganophosphonium carboxylate salt.

Abstract: A process for the redistribution of an organic polycarbonate composition. The process involves melt equilibrating a starting polycarbonate composition (which may be a single polycarbonate or a mixture of polycarbonates, and may be or include recycled polycarbonate) having an initial weight average molecular weight in the presence of a carbonate redistribution catalyst and in the absence of branching agents, under conditions such that a redistributed polycarbonate composition is formed having a weight average molecular weight different from, and typically lower than, the initial weight.

Abstract: Pigmented polycarbonate compositions which are substantially stable with respect to molecular weight and melt viscosity are prepared by blending a redistributed polycarbonate with titanium dioxide free from polysiloxane coatings (i.e., "unpacified" titanium dioxide).

Abstract: Spirobiindanol polydiorganosiloxane compounds are prepared by the reaction of an .alpha., .omega.-dichloropolydiorganosiloxane with a spirobiindane bisphenol in the presence of an acid acceptor. They are useful as intermediates in the preparation of copolysiloxanecarbonates.

Abstract: Copolysiloxanecarbonate compositions are prepared by the reaction of a carbonate precursor such as phosgene with a mixture of bisphenols including a spirobiindane bisphenol, at least one of said bisphenols containing polydiorganosiloxane moieties. The reaction may take place in one step or sequentially. The products are characterized by low processing temperature, low orientational birefringence and high ductility.