Surface treatment of poly(tetrafluoroethylene) and perfluoroethylene-propylene by radiation grafting

Ito, Naoki*; Mase, Atsushi*; Seko, Noriaki; Tamada, Masao; Sakata, Eiji*; Kogi, Yuichiro*

Polytetrafluoroethylene (PTFE) and perfluoro ethylene-propylene (PFEP) have many desirable properties for application to electronic devices, such as low dielectric constant and loss tangent. However, the weak adhesion of the polymer to various metals, associated with the chemical inertness of the fluorine resin surface, fails to satisfy many of the industry requirements. Surface treatment of PTFE and PFEP by radiation-induced graft polymerization was carried out to improve the adhesion. Peel adhesion strengths of 10.3 N/cm and 14.5 N/cm were attained for PTFE/Cu and PFEP/Cu, respectively by the treatment. In addition, the dielectric function of grafted PTFE and grafted PFEP remained almost unchanged after the graft polymerization.