Olefinic Elastomers for Wire and Cable Applications

摘要

Polymeric insulations and jacketing materials provide a reliable, cost-effective means of protecting cables, wires, and fibers used in today's power and data transmission applications. The choice of polymeric coating for a particular application is dictated by numerous factors including the electrical, environmental, and physical property requirements of the cable. Plastic and elastomeric compounds are two of the most common classes of materials used in the majority of wire and cable constructions. Polyethylene, one of the most popular plastics being used in the wire and cable industry due to its good performance and relatively low cost, maintains a large market share. Complementary to plastics, cables made using elastomeric compounds have their own distinct performance attributes due to their particular polymeric architecture.Elastomers are polymers that exhibit extreme elastic extensibility and flexibility when subjected to relatively low mechanical stress. Comparison of the polymeric architecture of polyethylene with three common commercially available elastomers (ethylene-octene (EO) (or -butene (EB)), chlorinated polyethylene (CM), and EPDM (ethylene propylene diene terpolymer) reveals the similarities and differences of these various classes of materials and provides insight into their performance characteristics. All of these polymers have a saturated backbone structure, but the flexibility, tactile nature, and performance of the compounds are very different. The more amorphous elastomeric EO/EB, CM, or EPDM materials tend to produce compounds that are more flexible than polyethylene compounds.This paper will provide an overview of the role of these elastomeric polymers in wire and cable applications and discuss the similarities and differences of the materials due to their polymer architecture. Emphasis will be on the elastomer resins. Structure-property relationships will be highlighted to help explain the major benefits and deficiencies that each polymer type offers for the wire and cable industry.Elastomers can participate in a broad range of applications, including thermoplastic or thermoset systems, such as jacketing, insulation, bedding, low-smoke zero halogen, and low-voltage insulation. Technical data on the use of these polymers in typical wire and cable applications will be presented for illustrative purposes.