Binder for electrode material, comprises tetrafluoroethylene group polymer microparticles having specific diameter and specific gravity, and has preset extrusion pressure when mixed with extrusion adjuvant

摘要

A binder comprises tetrafluoroethylene group polymer microparticles having a mean particle diameter of 0.2 Microm or less and a specific gravity of 2.2 or less. The microparticles are mixed with 17 wt.% extrusion adjuvant. The extrusion pressure of the mixture measured at a contraction ratio of 100/1 and an extrusion rate of 18 +- 2 mm/minute by a rheometer, is 220 kg/cm 2> or more.