METHOD OF SYNTHESIS OF POLYTETRAFLUOROETHYLENE Russian patent published in 2001 - IPC

FIELD: technology of polymers, organohalide compounds. SUBSTANCE: invention relates to method of synthesis of fluoroplastics. Method of synthesis of polytetrafluoroethylene involves polymerization stage in reactor-polyremizator in liquid medium with preliminary removal of oxygen from reactor volume by inert gas under increased pressure in the presence of oxidative- -reductive system consisting of persulfate and ferrous salt. Addition of persulfate and ferrous salt is carried out successively. Persulfate is added before or simultaneously with feeding tetrafluoroethylene into reactor-polymerizator. Ferrous salt is added in the process of tetrafluoroethylene feeding after making in reactor-polymerizator at least 10% of working pressure used for polymerization process. Polymerization process is carried out at 2-14 ati followed by separation of the end product from mother liquor, its washing out, grinding and drying. Ferrous salt content in liquid medium is from 0.05 to 99.0 mg/l and persulfate content is from 1 to 15 mg/l as measured for ammonium persulfate and at consumption of ferrous salt and persulfate 0.00016-0.26532 and 0.0032-0.04 g/1 kg of tetrafluoroethylene, respectively. Invention provides stabilization of polymerization process and molecular mass of product and increase of yield of the end product to 95-98%. EFFECT: enhanced economy, improved quality, competitive ability, technological effectiveness, increased yield. 22 cl, 2 ex