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US 4,229,565 AGranted
Preparation of polyarylates from dihydric phenols, aromatic dicarboxylic acid and a chlorinating agent
AssigneeUnion Carbide Corporation
InventorsHugh C. Gardner, Markus Matzner
Life of this patent
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Abstract
High molecular weight, thermally stable polyarylates are prepared directly from dihydric phenols, aromatic dibasic acids and a chlorinating agent without isolating an acyl halide intermediate. An organic phosphite can be added to reduce color formation.
Claims13
A method for preparing polyarylates which comprises:
- (a) mixing at least one aromatic dicarboxylic acid having 8 to about 20 carbon atoms with a stoichiometric excess of a chlorinating agent,
- (b) heating the mixture from (a) at a temperature of about 25.degree. to about 180.degree. C., until essentially all of the dicarboxylic acid groups are reacted,
- (c) removing unreacted chlorinating agent,
- (d) determining the amount of active chlorine in the resultant mixture,
- (e) adding an approximately stoichiometric amount of at least one dihydric phenol, based on the amount of active chlorine present, and
- (f) polymerizing the mixture from step (e) until a polyarylate having a reduced viscosity of at least 0.4 in p-chlorophenol at 49.degree. C. at a concentration of 0.2 g/dl. forms.
3 more elements
Dependencies are inferred from the claim text.