Jacketing Insulations
JACKETS – Applied over primary insulation, shields, cable components or over the cable itself; includes many of the primary insulating materials, containing nylon, neoprene, hypalon, ethylene-propylene rubber, polyurethane, etc. Jackets cover and protect the enclosed wires or core against damage, chemical attack, fire and other harmful elements which may be present in the operating environment.
Common Jacket Types:
- PVC is a thermoplastic inherently flame and abrasion resistant material that is specially compounded for general-purpose applications at temperatures to 105°C.
- TPE is thermoplastic elastomer or TPR. Thermoplastic rubber has mechanical characteristics of thermoset rubbers yet is a thermoplastic. They have excellent ozone and chemical resistance, excellent electrical properties and low water absorption. Temperature range is -70°C to 125°C.
- Polyurethane has exceptional resistance to oil, radiation, fungus, oxidation and ozone. It is unusually tough, has higher tensile strength and elongation, more abrasion resistance and better low temperature flexibility than neoprene. Its major disadvantage is poor resistance to steam, high temperatures and acids. But it has outstanding "memory" properties, making it an ideal jacket material for retractile cords. Since it is an expensive material, it is only specified when other jacket materials will not satisfy the requirements of the application.
- Low Density Polyethylene (LDPE) is a very good insulation in terms of electrical properties. Featuring a low dielectric constant, a stable dielectric constant over all frequencies and a very high insulation resistance, LDPE is fairly flexible. Moisture resistance is excellent, but LDPE is flammable.