ELECTRET HAVING IMPROVED STABILITY

摘要

In a process for the production of an electret composed of a high molecular weight base material by applying to the base material a high D. C. potential at a high temperature, cooling the material while continuing the application of the potential, and then removing the electric potential, the improvement which comprises covering the opposite surfaces of the base material before polarizing the base material with thin films of a different high molecular weight material having a higher electrical insulating property than that of the base material prior to the application of the electric potential.