Method of converting fluorine-containing polymer into lower molecular weight polymer
AssigneeCentral Glass Company, Limited
InventorsMinoru Aramaki, Hisazi Nakano, Masahiro Kubo
Life of this patent
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Abstract
A fluoropolymer, e.g. polytetrafluoroethylene, is easily and efficiently converted into a lower molecular weight polymer in the form of a fine powder by subjecting the fluoropolymer to contact reaction with a gas comprising molecular fluorine or a suitable fluoride such as nitrogen trifluoride or xenon difluoride at a temperature between the melting temperature of the fluoropolymer and 600.degree. C., extracting a hot reaction gas produced by the contact reaction from the reactor and cooling the extracted reaction gas to a temperature not high than 100.degree. C. to thereby precipitate the molecular weight reduced fluoropolymer contained in the hot reaction gas as vapor.
Claims11
A method of converting a fluorine-containing solid polymer into a lower molecular weight polymer in the form of fine particles, comprising the steps of:
- heating a fluorine-containing solid polymer in a reactor to a temperature not lower than the melting temperature of the fluorine-containing polymer and not higher than 600.degree. C. and subjecting the heated fluorine-containing polymer to contact reaction with a fluorinating gas while maintaining the gas phase in the reactor at a temperature in the range from 200.degree. to 550.degree. C. such that a lower molecular weight polymer is formed by reaction of the fluorinating gas with the fluorine-containing polymer and a major portion of the lower molecular weight polymer exists as a gas phase in a hot reaction gas produced by the contact reaction, said fluorinating gas comprising at least one fluorine source material selected from the group consisting of molecular fluorine, nitrogen trifluoride, halogen fluorides and fluorides of rare gas elements;
- extracting said hot reaction gas from the reactor;
- and
- cooling the extracted reaction gas to a temperature not higher than 100.degree. C. thereby precipitating submicron particles of the lower molecular weight polymer from the reaction gas.
Dependencies are inferred from the claim text.