Jackets and Insulation
PVC is referred to as vinyl or polyvinyl chloride. PVC comes in two basic forms: rigid and flexible. The rigid form of PVC is used in construction for pipe and other applications, It can be made softer and more flexible by the addition of plasticizers, In this form, it is used in electrical cable insulation. Before PVC can be made into finished products, it always requires conversion into a compound by the incorporation of additives such as heat stabilizers, UV stabilizers, plasticizers, impact modifiers, thermal modifiers, flame retardants, pigments etc. depending on the need. There are many varieties of PVC based on applicability and electrical properties requirements.
PE is a very good insulator in terms of electrical properties with a stable dielectric constant over all frequencies and very high insulation resistance with good moisture resistance. In terms of flexibility, polyethylene is rated stiff to very hard, depending on molecular weight and density with low density being the most flexible, with high-density being hard. Flame retardant formulations are available.
This material has excellent electrical properties, temperature range and chemical resistance. It is not suitable for installation in nuclear radiation environment. Teflon does not have good high voltage characteristics. FEP Teflon is extrudable in a manner similar to PVC and Polyethylene. This means that long wire and cable lengths are available. TFE Teflon is extrudable in a hydraulic ram type process. Lengths are limited due to amount of material in the ram, thickness of the insulation, and perform size. TFE must be extruded over a silver or nickel-coated wire. The nickel and silver-coated designs are rated 260° C and 200° C maximum, respectively. The cost of Teflon is approximately 8 to 10 times more per pound than PVC compounds.
Polypropylene has similar electrical properties like polyethylene and primarily used as an insulation material. Being harder than polyethylene, polypropylene is suitable for thin wall insulations. UL maximum temperature rating may be 60° C or 80° C. Most UL styles call for 60° C maximum. The dielectric constant is 2.25 for solid.
This is a very soft insulation which has a temperature range from -80° C to 200° C. It has excellent electrical properties plus ozone resistance, low moisture absorption, weather resistance, and radiation resistance. It typically has low mechanical strength and poor scuff resistance.
The temperature range of this material can vary from -55° C to 90° C. The actual range would depend on the formulation used. Neoprene is both oil resistant and sunlight resistant, making it ideal for many outdoor applications. The most stable colors are Black, Dark Brown, and Gray. The electrical properties are not as good as other insulation materials. Because of this, thicker insulation should be used. Typical designs where this material is used are lead wire insulation and cable jackets.
This material is used primarily as a cable jacket material. It has excellent oxidation, oil, and ozone resistance. Some formulations also have good flame resistance. It is a hard material with excellent abrasion resistance. It has outstanding "memory" properties, making it an ideal jacket material for retractile cords.