Purification and adhesion of fluoropolymers
AssigneeE. I. Du Pont de Nemours and Company
InventorsRobert J. Cavanaugh, William H. Tuminello
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Abstract
A process for purifying fluoropolymers by contacting them at temperatures above 140.degree. C. with a liquid perfluorinated cycloalkane. The resulting polymers are particularly useful where polymers with reduced impurities are desirable, such as in medical devices and in parts for the semiconductor manufacturing industry. The liquid perfluorinated cycloalkanes improve the adhesion of fluoropolymer to themselves and other materials.
Claims30
A process for the purification of fluoropolymers, comprising, contacting, at an extraction temperature of about 140.degree. C. or more, a fluoropolymer with a liquid perfluorinated cycloalkane, provided that:
- said fluoropolymer has a melting point of about 200.degree. C. or more;
- said extraction temperature is below said melting point;
- and
- said perfluorinated cycloalkane has a boiling point of about 140.degree. C. or more at atmospheric pressure.
A process for adhering a fluoropolymer surface to another surface, comprising, coating a fluoropolymer surface with a perfluorinated cycloalkane or a solution of a fluoropolymer in a perfluorinated cycloalkane to make a coated fluoropolymer surface, contacting said coated fluoropolymer surface with another surface, and then applying pressure to force said coated fluoropolymer surface and said another surface together, to adhere said fluoropolymer surface to said another surface, provided that:
- the process is carried out at a temperature below the perfluorinated cycloalkane's atmospheric pressure boiling point;
- said perfluorinated cycloalkane has a boiling point of about 140.degree. C. or more at atmospheric pressure;
- and
- said fluoropolymer has a melting point of about 200.degree. C. or more.
Dependencies are inferred from the claim text.