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US 5,496,921 AGranted
Melt process for polycarbonate with improved heat stability
AssigneeGE Plastics Japan, Ltd.
InventorsTakeshi Sakashita, Tomoaki Shimoda
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Abstract
Polycarbonates are prepared by inducing the melt polycondensation of an aromatic dihydroxy compound and a diester carbonate in the presence of alkali metal compounds and/or alkaline earth metal compound droxy and adding to the polycarbonate which is the reaction product thereof: a sulfonic acid compound having the formula ##STR1## in an amount of 0.05-10 ppm, based on the polycarbonate, an epoxy compound in an amount of 1-2000 ppm, based on the polycarbonate and a phosphorus compound in an amount of 10-1000 ppm, based on the polycarbonate.
Claims12
A method for preparing polycarbonates comprising
- a) melt polycondensing an aromatic dihydroxy compound and a diester carbonate in the presence of a total amount in the reaction system of 5.times.10.sup.-8 to 8.times.10.sup.-7 mole of an alkali metal compound or an alkaline earth metal compound per mole of the aromatic dihydroxy compound and
- b) adding to the polycarbonate which is the reaction product thereof:
- a sulfonic acid compound of the formula ##STR7## where R.sup.7 is a hydrocarbon group having 1-6 carbons in which the hydrogens may be substituted with halogens, R.sup.8 is a hydrocarbon group with 1-8 carbons in which the hydrogens may be substituted with halogens and n is an integer from 0 to 3 in an amount of 0.05-10 ppm, based on the weight of the polycarbonate,
- an epoxy compound in an amount of 1-2000 ppm, based on the weight of the polycarbonate, and also
- a phosphorus compound in an amount of 10-1000 ppm based on the weight of the polycarbonate.
2 more elements
Dependencies are inferred from the claim text.