METHOD OF PROCESSING COPOLYMERS OF TETRAFLUOROETHYLENE-BASED Russian patent published in 1995 - IPC

FIELD: processes for preparing copolymers. SUBSTANCE: the production process is simplified by reducing pressure and shortening the process time. The process for preparing tetrafluoroethylene copolymers by is carried out by copolymerizing tetrafluoroethylene with hexafluoropropylene and perfluoromethyl vinyl ether in the presence of a radial initiator and a fluorinated surface active agent. Perfluoropolyether is added which is selected from the group consisting of CF₃O{[CF₂-CFO (CF₃)]_n[CF₂O]_m}CF₃ wherein n/m=40, CF₃O[(CF₂CF₂O)_n(CF₂O)_m] CF₃ wherein n/m=0.6-0.7, C₃F₇[(CF(CF₃)- CF₂O)_n C₂F₅ wherein n= 13, m. w. 500-2400. Perfluorpolyether is used in an amount of 0.25-0.99 ml/l of an aqueous solution of the emulsifier. Perfluoropolyether is added to an aqueous phase as an aqueous microemulsion in admixture with a fluorinated surface active agent is prepared. The microemulsion is prepared at 60-90 C followed by addition of the other ingredients and aqueous emulsion copolymerization. The content of tetrafluoroethylene in a monomer mixture is 37 mole % by copolymerization with hexafluoropropylene, and 88.43-98.4 mole % by copolymerization with perfluoromethylvinyl ether. EFFECT: improved process for preparing copolymers. 2 cl