Why use silicone rubber for the insulation and sheathing material ?
Rubber has been used as cable insulation and sheathing material long before other insulation such as PVC and PE can to be commonly applied. It remains widely used across domestic and industrial applications.
Initially, natural rubbers were used but these have been largely replaced by various synthetic rubbers. All rubbers are thermoset or cross-linked by a process referred to as Vulcanisation.
As thermoset materials they do not soften or melt when exposed to heat.The principle advantage of all rubber cables over other insulated cables is the excellent flexibility in temperature range. They also have very good water absorption properties. Many rubber cables also have superior abrasion resistance and weathering resistance making them particularly suitable in harsh environments as trailing leads for portable electrical appliances, power tools, pumps and generators. Rubber cables are also compounded to give excellent resistant to oils and other chemicals.
Silicone rubber insulated cables have outstanding thermal range with some suitable for high temperatures up to 200oC and lows down to -90°C. Silicone rubber cables also have excellent flexibility. Whilst silicone rubber insulation doesn’t offer the same mechanical toughness and cut-through resistance when compared to most other elastomers, this can be compensated for with the addition of a glass fibre braid and silicone varnish.