Because of its unique properties, silicone rubber has been gradually applied in many fields. Compared with ordinary rubber, the Si-O bond in silicone rubber has higher energy and is not easy to break, which makes silicone rubber has excellent heat and cold resistance. It can be used for a long time within 250~300℃, but also has low temperature flexibility. It will not harden and become brittle even if the temperature is reduced to -50℃. With the expansion of the social demand for electricity, such materials as silicone rubber are widely used in wires, cables and electrical components because of their excellent electrical insulation properties.

At the same time, the scope of its use has been expanded from the application of insulating products to conductive or semi-conductive products. Silicone rubber as insulation, moisture, shock and perfusion and filling material, compared with other insulating materials, excellent electrical insulation properties, the dielectric loss, voltage resistance, arc resistance, corona resistance and volume resistivity and other parameters on top in the insulation material, and their electrical performance is affected by temperature and frequency is small. Electrical insulation is rarely reduced even after immersion in water.

Volume resistivity
Volume resistivity (volume resistance, refers to the resistance per unit cubic volume, used to characterize the size of the conductivity of the material, and the reciprocal relationship between the conductivity, is an important indicator of the insulation performance of the material, according to the size of the volume resistivity, the material is divided into conductor (ρ V< 10-8 ω.cm), semiconductor (10-8 ω.cm< Rho v< 108 ω.cm) and insulation (ρ v> 10-8 Ω. Cm). Silicon rubber as an excellent insulator material, its volume resistivity can be maintained at 1014 ω.cm~1016 ω.cm, far beyond the requirements of ordinary polymer material insulation.

Breakdown voltage strength
Breakdown voltage strength refers to the fact that when the electric field increases to a certain extent, the dielectric suddenly changes from an insulating state to a conductive state. It is a measure of the material's ability to withstand high voltage without generating dielectric breakdown, and the unit is kV/mm. During the test, the sample is placed between electrodes and the applied voltage is slowly increased through a series of steps until electrical breakdown occurs, at which point the voltage strength is recorded. The higher the breakdown voltage of a substance is, the better its quality as an insulator is. As an excellent insulator material, silicon rubber has a breakdown voltage strength of 15~30kV/mm, which can meet most applications.

The tangent of dielectric constant and dielectric loss Angle
Dielectric constant: The ratio of the capacitance of a capacitor of the same size made of an insulating material to a vacuum medium, indicated by the letter ε. It represents the degree of polarization of the material under the action of an electric field. Used as an insulating medium requires a smaller ε, used as a capacitor requires a larger material ε.

Tangent value of dielectric loss Angle: tangent value of tangent of residual Angle of phase Angle δ between sine wave voltage applied to dielectric and current of the same frequency - tanδ. The smaller tanδ is, the smaller the energy loss is. Generally, the tangent value of the loss Angle of silicone rubber is less than 10-3.