Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2004-02-20
2009-12-08
Boykin, Terressa M (Department: 1796)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
C502S162000, C502S164000, C528S198000, C528S204000
Reexamination Certificate
active
07629431
ABSTRACT:
A polycarbonate prepolymer for solid state polymerization, which is produced by an oxidative carbonylation reaction of an aromatic dihydroxy compound, a monohydric phenol having a boiling point of 330° C. or below, carbon monoxide and oxygen, the polycarbonate prepolymer being characterized by that (a) a ratio of aryl carbonate groups and hydroxyl groups each constituting terminal groups of the prepolymer is from 2:8 to 8:2, and (b) a molecular weight distribution (Mw/Mn) is from 1.1 to 2.1; and a process of producing polycarbonates including a step of solid state-polymerizing the prepolymer so as to increase the molecular weight thereof. According to the present invention, the prepolymer having a controlled molecular weight distribution suitable for solid state polymerization is provided, and a high quality polycarbonate is efficiently produced in environmentally friend manner.
REFERENCES:
patent: 6399738 (2002-06-01), Ito
patent: 90/07536 (1990-07-01), None
Boykin Terressa M
Idemitsu Kosan Co. Ltd.
Oblon, Spivak McClelland, Maier & Neustadt, L.L.P.
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