METHOD OF PREPARING AQUEOUS DISPERSION OF TETRAFLUOROETHYLENE COPOLYMER Russian patent published in 2000 - IPC

FIELD: chemistry of polymers. SUBSTANCE: aqueous dispersion of tetrafluoroethylene copolymer with 10-18 mole % of hexafluoropropylene is prepared by aqueous emulsion copolymerization of said monomers in the presence of perfluorinated emulsifier, water-soluble initiator by optional addition of pH value regulator and introduction of mixture consisting of 70-75 mole % of hexafluoropropylene and 25-30 mole % of tetrafluoroethylene followed by additional feeding. Additional feeding is carried out by mixture of monomers which contains 8-11 mole % of hexafluoropropylene and 89- 92 mole % of tetrafluoroethylene, and process is conducted at 65-76 C and pressure of 0.7-1.5 MPa. The resulting polymer dispersions prepared under conditions as mentioned above are concentrated to form high grade suspensions. EFFECT: high quality characteristics of the resulting copolymer. 5 cl, 25 ex, 2 tbl