The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 24, 2004
Filed:
Oct. 16, 2002
James Manio Silva, Clifton Park, NY (US);
Pierre-Andre Bui, Clifton Park, NY (US);
Thomas Joseph Fyvie, Schenectady, NY (US);
David Michel Dardaris, Ballston Spa, NY (US);
General Electric Company, Niskayuna, NY (US);
Abstract
A new method of converting oligomeric chloroformates to high molecular weight polycarbonate is presented. By carefully controlling the relative concentrations and amounts of hydroxyl and chloroformate groups present in the oligomeric polycarbonate, the method of the invention provides for the efficient preparation of polycarbonate while minimizing phosgene usage. The product polycarbonates prepared by the method of the invention are fully capped with no additional phosgene required beyond that needed to prepare the oligomeric chloroformate starting material. The method of the present invention provides polycarbonates having non-detectable levels (<5 ppm) of aromatic hydroxyl endgroups, low polydispersity, and low levels of residual monomer and endcap, thereby obviating the need for monomer and endcap recycle.