Verfahren zur Polymerisation von Tetrafluoraethylen

摘要

Gaseous tetrafluorethylene is polymerized in aqueous emulsion and monomer and emulsifying agent are introduced progressively at rates such that the concentration of emulsifying agent is proportional to the total surface area of the polymer particles, whereby at least 60% of the surface area of the particles is continously covered with emulsifying agent. Preferred emulsifying agents are alkali or ammonium salts of fluoro- or chlorofluoro-aliphatic C6+ carboxylic acids. Monomer and emulsifier are added continuously or in batches and in the latter case together or alternately using at least 3 additions. Catalyst may be potassium persulphate-ferrous sulphate, succinyl peroxide or glutaryl peroxide and there may also be present paraffin oil and a buffering agent.