Cyclic polyester oligomer polymerization
AssigneeGeneral Electric Company
InventorsDaniel J. Brunelle, Thomas G. Shannon
Life of this patent
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Abstract
Cyclic polyester and especially polyarylate oligomers, typically having degrees of polymerization from 2 to about 7, are prepared by reacting a bisphenol such as bisphenol A or 6,6'-dihydroxy-3,3,3',3'-tetramethylspiro(bis)indane with a dicarboxylic acid chloride such as isophthaloyl or terephthaloyl chloride in the presence of a catalyst, under conditions of low concentration. The cyclic oligomers may be polymerized to linear polyesters by contact with a transesterification catalyst at a temperature in the range of about 200.degree.-300.degree. C.
Claims9
A method for preparing a linear polyester which comprises contacting with a transesterification catalyst, at a temperature in the range of about 200.degree.-300.degree. C., a composition comprising cyclic polyester oligomers of the formula ##STR4## wherein each of A.sup.1 and A.sup.2 is a monocyclic divalent aromatic radical, A.sup.3 is a divalent aliphatic or m- or p-linked monocyclic aromatic or alicyclic radical, Y is a single bond or Y is a divalent bridging group and n is from 2 to about 7.
A method for preparing a linear polyester which comprises contacting with a transesterification catalyst, at a temperature in the range of about 200.degree.-300.degree. C., a composition comprising cyclic polyester oligomers of the formula ##STR5## wherein A.sup.3 is m- or p-phenylene and n is from 2 to about 7.
Dependencies are inferred from the claim text.