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:
Apr. 13, 2010
Filed:
Jun. 30, 2008
Laura G. Schultz, Evansville, IN (US);
James A. Mahood, Evansville, IN (US);
Brian D. Mullen, Plymouth, MN (US);
Laura G. Schultz, Evansville, IN (US);
James A. Mahood, Evansville, IN (US);
Brian D. Mullen, Plymouth, MN (US);
SABIC Innovative Plastics IP B.V., Bergen op Zoom, NL;
Abstract
Methods for making a branched polycarbonate are disclosed. An interfacial mixture comprising water, a substantially water-immiscible organic solvent, a dihydroxy compound, a polyhydric branching agent, an endcapping agent, a catalyst, and a base is formed. The base and the branching agent are dissolved in the mixture before the dihydroxy compound is added, and the interfacial mixture has a basic pH. The mixture is reacted by adding a carbonate precursor to the mixture while maintaining the pH between about 8 and about 10 to form the branched polycarbonate. The resulting branched polycarbonates may contain more than 1.5 mole % of the THPE; have residual chloride content of 20 ppm or less; and a weight average molecular weight of about 55,000 or less. They may also be highly transparent.