They provide rubberlike flexibility, toughness (over a wide temperature range), and remain flexible under cold outdoor conditions. Brittleness points range from –60 to –100°C (–76 to –148°F). The compounds have typical dielectric strengths of 600 to 900 V/mil and dielectric constants of 2.1 to 2.4. Depending on grade, maximum continuous operating temperatures, as defined in UL- 1581, range from 105 to 125°C (221 to 257°F). The TPEs also have lower specific gravity than standard flexible vinyl compounds, resulting in lighter wires and cables. Many grades are UL recognized, meeting requirements for outdoor weathering and UV resistance. A representative compound, EL-8431, has a 69 Shore A hardness, a specific gravity of 0.93, tensile strength of 19.8 MPa (2.9 kpsi), ultimate elongation of 650%, maximum continuous operating temperature of 105°C, and oxygen index of 18%.
Teknor Apex, Thermoplastic Elastomer Div., 505 Central Ave., Pawtucket, RI 02861, (866) 438-8737, teknorapex.com