Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2006-10-17
2006-10-17
Boykin, Terressa (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
C528S196000, C528S198000
Reexamination Certificate
active
07122613
ABSTRACT:
A method for the manufacture of a polycarbonate which comprises reacting a carbonate precursor with a dihydroxy compound in the presence of an aqueous base in an inert organic solvent optionally containing a molecular weight regulator to form an oligomeric polycarbonate, wherein the reaction between the dihydroxy compound and the carbonate precursor is about 80 to about 99% completed; removing the inert organic solvent and the aqueous base to isolate the oligomeric polycarbonate; and transesterifying the isolated oligomeric polycarbonate to form a polymeric polycarbonate at a temperature and pressure effective to remove trace amounts of residual solvent. This method eliminates some of the problems of the prior art such as the removal of solvent from high molecular weight polycarbonate, which is both cumbersome, energy intensive and expensive.
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Jos Peemans Rudy Francois Alain
Kamps Jan Henk
Schipper Eugène Theodorus Wilhelmus Maria
Zirkzee Hendricus Franciscus
Boykin Terressa
General Electric Company
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