Patent ID: 7345116

Claim:
A method for preparing an optically clear thermoplastic resin composition comprising the steps of: (a) melting a polycarbonate and a polyester to form a molten mixture, wherein the polyester comprises structural units derived from terephthalic acid and a mixture of 1,4-cyclohexane dimethanol and ethylene glycol, and said ethylene glycol is greater than 60 mole percent based on total moles of 1,4-cyclohexane dimethanol and ethylene glycol, (b) extruding said molten mixture in an extruder to form an extrudate, wherein the extruder is a low torque extruder comprising a plurality of screw elements extending from an upstream feed end to a downstream exit end, and wherein screw elements disposed between the feed end and a first kneading block are progressively compressed in the direction of the first kneading block to increase fill at the first kneading block, and wherein molten mixture is formed and extruded without addition of supplemental catalyst; and (c) molding the extrudate into an optically clear thermoplastic resin composition.