Devolatilization
AssigneeNovacor Chemicals (International) S.A.
InventorsSteven M. Krupinski, James T. McQueen
Life of this patent
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Abstract
A polymer melt may be devolatilized to less than 500, preferably less than 150 ppm of residual volatile material by injecting into the melt an amount of a super critical fluid greater than the amount of residual volatile material in the melt, typically not more than about 10 weight %, and passing the melt through a flash chamber devolatilizer at a pressure of 12 mm of Hg or less at a temperature of from 200.degree. to 350.degree. C.
Claims23
A process for reducing the amount of residual monomer, and solvent to less than 300 parts per million in a polymer or polymer blend containing less than 5 weight % of such residual monomer, and solvent which process comprises:
- (i) heating and maintaining said polymer or polymer blend as a melt at a temperature from 200.degree.-270.degree. C.;
- (ii) injecting into said melt an amount of a non-oxidizing super critical fluid greater than the amount of residual monomer, and solvent but less than 5 weight %, said injection being at temperatures of from 200.degree. to 270.degree. C. and pressures to dissolve the super critical fluid in said melt;
- and
- (iii) maintaining said melt at a temperature from 200.degree.-270.degree. C. while exposing said polymer to a pressure maintained at less than 8 Torr.
Dependencies are inferred from the claim text.