Abstract: Thermoplastic materials having a low dielectric loss tangent and loss index are bonded together using radio frequency energy by employing a polyvinyl chloride buffer above and below the materials being bonded while applying pressure and rf energy. The polyvinyl chloride is a highly plasticized polyvinyl chloride which has a bonding temperature lower than the bonding temperature of the material being bonded. In spite of the fact that the bonding temperature of the polyvinyl chloride is lower than the bonding temperature of the low loss material an effecitve bond is produced between the low loss material.