METHOD OF PRODUCING TETRAFLUOROETHYLENE COPOLYMERS WITH 12-15 MOL % OF HEXAFLUOROPROPYLENE Russian patent published in 1998 - IPC

FIELD: polymer production. SUBSTANCE: invention relates to electroinsulating, chemically stable, and heat resistant materials in aviation, construction, equipment for drilling deep oil wells, as protection films and coatings in chemical industry, etc. Tetrafluoroethylene copolymers with 12-15 mol % hexafluoropropylene are produced through copolymerization of indicated monomers in fluorine-containing solvent or in monomer mass at elevated pressure in presence of perflourinated radical-type initiator. Monomer mixture charge consists of 80-86 mol % hexafluoropropylene and 14-20 mol % tetrafluoroethylene. In the course of copolymerization, content of monomers is replenished: before 50-70 wt % of total amount of replenishing mixture is consumed under specified working pressure, replenishing mixture contains 12-15 mol % hexafluoropropylene and 85-88 mol % tetrafluoroethylene. Further, process pressure is raised by 0.1-0.2 MPa and replenishing is effected with mixture containing 8-11 mol % hexafluoropropylene and 89-92 mol % tetrafluoroethylene. As perflourinated initiator, utilized may be perfluorocyclohexanoyl peroxide (at 45-47 C and working pressure 1.4-1.5 MPa), or perfluoropropionyl peroxide (25-30 C and 1.1-1.3 MPa), or perfluoro-2-methyl-3-oxahexanoyl peroxide (25- 30 C and 1.1-1.3 MPa). Fluorine-containing solvent is ocatfluorocyclobutane that is ozone-safe solvent. EFFECT: increased productivity of process. 6 cl, 1 tbl