DIFFUSION FILM, ELECTRODE HAVING THE DIFFUSION FILM, AND PROCESS FOR PRODUCING DIFFUSION FILM

摘要

A diffusion film comprising unburned polytetrafluoroethylene (PTFE), burned PTFE, and a conductive substance; an electrode comprising the diffusion layer (film) and a catalyst layer disposed on a surface thereof; and a process for producing a diffusion film which comprises dispersing unburned PTFE, burned PTFE, and a conductive substance into a dispersion liquid, subsequently removing the dispersion liquid, adding a liquid lubricant, kneading the mixture, subsequently rolling the mixture (preferably rod-shape preform) to form a film, and then removing the liquid lubricant. Preferably, the diffusion film has an unburned-PTFE content of 1 to 30 wt.% and a burned-PTFE content of 5 to 30 wt.%. The conductive substance desirably comprises a combination of graphite and carbon black. Thus, a diffusion film which has evenness of properties throughout and is suitable for mass production can be provided at low cost.