| US 7,541,420 B2 | ||
| Method for making molded polycarbonate articles with improved color | ||
| Sjef Berndsen, Rilland (Netherlands); Hans Peter Brack, Herrliberg (Switzerland); Bernd Jansen, Bergen Op Zoom (Netherlands); Jan Henk Kamps, Bergen op Zoom (Netherlands); Edward Kung, Bergen op Zoom (Netherlands); Daniel Lowery, Schenectady, N.Y. (US); Patrick Joseph McCloskey, Watervliet, N.Y. (US); Paul Michael Smigelski, Jr., Schenectady, N.Y. (US); and Dennis Willemse, Roosendaal (Netherlands) | ||
| Assigned to Sabic Innovative Plastics IP B.V., Bergen op Zoom (Netherlands) | ||
| Filed on Mar. 20, 2007, as Appl. No. 11/688,533. | ||
| Claims priority of provisional application 60/806312, filed on Jun. 30, 2006. | ||
| Prior Publication US 2008/0004407 A1, Jan. 03, 2008 | ||
| Int. Cl. C08G 64/00 (2006.01); C08G 63/02 (2006.01) | ||
| U.S. Cl. 528—196 [524/115; 524/130; 524/133; 525/394; 525/471; 528/198; 528/425; 548/471; 548/472] | 26 Claims |
| 1. A method for preparing a molded article comprising the steps of:
(a) obtaining a polycarbonate resin, said polycarbonate having been made by a transesterification reaction using an ester-substituted
diaryl carbonate such that the polycarbonate is susceptible to the formation of internal ester linkages (IEL) having the structure
 (b) molding the polycarbonate resin to form the article, wherein the polycarbonate resin, the molding conditions or both are
selected to control the amount of IEL formed during the molding process to a level of less than 0.4 mol %.
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