PVC, according to the hardness and performance of the material generally have 7 levels (SG1-SG7), the density of 1.4 g/cm³ or so. SG4 below the general soft products, in the moulding of a large number of plasticisers, mainly used for the production of artificial leather, wire and cable insulation, seals, etc. SG5 above the hard products, mainly used for making a variety of pipes, such as drainage, electricians, postal and electrical pipes and pipe fittings, a variety of PVC moulding shrinkage rate of 0.6-1.5%, has good mechanical properties, its electrical properties are excellent, and has a self-extinguishing, acid and alkali resistance is very strong, chemical stability, low price, is a very common application of general-purpose plastics. But because of its use temperature is not high, up to about 80 ℃, hindering its development.

Rubber insulation material is elastic closed-cell elastic material, with soft, resistant to winding, cold, heat, flame retardant, waterproof, low thermal conductivity, shock absorption, sound absorption and other excellent performance, neat and beautiful appearance, can be widely used in central air-conditioning, construction, chemical industry, textile, metallurgy, dissemination, vehicles, electrical appliances, and other industries and part of all kinds of hot and cold media pipelines, containers, can achieve to reduce the effect of cold loss and heat loss. Plus the construction is simple, and the product does not contain fibre dust, will not breed any mould and other harmful substances, so it is a cross-century new generation of insulation materials.