DISPERSION CONTAINING TETRAFLUOROETHYLENE COPOLYMER PARTICLE AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To obtain a powder or dispersion having a small mean primary particle diameter and a high number-average molecular weight and being useful as e.g. a binder for batteries by using particles comprising a copolymer obtained by polymerizing tetrafluoroethylene with a fluorinated comonomer and having a specified molecular weight and having a specified mean primary particle diameter. SOLUTION: This powder or dispersion comprises particles having a mean primary particle diameter of 0.01-0.20μm and comprising a copolymer having a number-average molecular weight of 1.0×10<7> to 1.0×10<8> and obtained by polymerizing tetrafluoroethlene with a fluorinated comonomer desirably being chlorotrifluoroethylene, a (perfluoroalkyl)ethylene, a perfluoro(alkyl vinyl ether) or hexafluoropropylene. It is desirable that the copolymer particles have each a core/shell structure in which the core is made from a copolymer in which the content of polymer units derived from the fluorinated comonomer is 0.01-0.5 mol.% and is higher than that of polymer units derived from the fluorinated comonomer in the shell.