VERFAHREN ZUR HERSTELLUNG VON MODIFIZIERTEN TETRAFLUORAETHYLEN-DISPERSIONSPOLYMERISATEN

Process for the preparation of extrudable tetrafluoroethylene polymers in the form of pastes, by polymerization of tetrafluoroethylene in the presence of customary catalysts, dispersing and modifying agents and, optionally, anticoagulants, and also possibly by preparing an aqueous seed dispersion, consisting of dispersed particles, beforehand. Of polytetrafluoroethylene or of a copolymer based on tetrafluoroethylene and a fluorolefin compound and containing at least 90% by weight of polytetrafluoroethylene units, as well as by subsequent coagulation and drying, characterized in that the polymerization of tetrafluoroethylene is carried out in the presence of, 0005 to 1.5% by weight (relative to the tetrafluoroethylene used, without taking into account any previous dispersion of seeding) of a perfluorinated vinyl ether of the formula ** (formula) ** where N-0 to 4, or of a mixture of these perfluorinated vinyl ethers, as ag modifying entity (Machine-translation by Google Translate, not legally binding)