Patent ID: 10865257

Abstract:
To provide a production method for an aqueous emulsion of modified polytetrafluoroethylene which is environmentally friendly and which is suitable for producing a stretched porous body having excellent breaking strength. A production method for an aqueous emulsion of modified polytetrafluoroethylene, which is a method to obtain an aqueous emulsion of modified polytetrafluoroethylene particles having an average primary particle diameter of from 0.10 to 0.30 μm, by subjecting tetrafluoroethylene and a perfluoroalkyl ethylene to emulsion polymerization in an aqueous medium, using a polymerization initiator, in the presence of a fluorinated anionic surfactant having a LogPOW of from 2.4 to 3.4, wherein the amount of the perfluoroalkyl ethylene to be used, is from 120 to 3,000 ppm to the final production amount of the modified polytetrafluoroethylene; at the initiation of the emulsion polymerization, the entire amount of the perfluoroalkyl ethylene is permitted to be present, and, as the polymerization initiator, either one or both of a combination of a bromate and a bisulfite or sulfite, and a combination of a permanganate and oxalic acid, are used.