Due to 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 have excellent heat resistance and cold resistance. It can be used for a long time in 250 ~ 300 ℃, and it also has low temperature flexibility. Even if the temperature is reduced to - 50 ℃, it will not become hard and brittle. With the expansion of power demand, silicone rubber is widely used in wires, cables and electrical components due to its excellent electrical insulation properties.
At the same time, its application range is also extended from insulating products to conductive or semi conductive products. Compared with other insulating materials, silicone rubber has excellent electrical insulation performance. Its dielectric loss, voltage resistance, arc resistance, corona resistance, volume resistivity and other parameters are among the best in insulating materials, and their electrical performance is little affected by temperature and frequency. Even after being soaked in water, the electrical insulation is rarely reduced. The general performance parameters are as follows.
In view of many small partners do not know about the electrical properties of sealant, Xiaobian now introduces how the electrical properties of silicone rubber are and what role it plays in various properties of sealant.
Volume resistivity
Volume resistance refers to the resistance per unit cubic volume, which is used to characterize the conductivity of the material and has a reciprocal relationship with the conductivity. It is an important index of the insulation performance of the material. According to the volume resistivity, the material is divided into conductor (ρ V & lt; 10-8 Ω. Cm), semiconductor (10-8 Ω. CM & lt; ρ V & lt; 108 Ω. Cm) and insulator (ρ V & gt; 10-8 Ω. Cm). As an excellent insulator material, the volume resistivity of silicone rubber can be kept in the range of 1014 Ω. Cm ~ 1016 Ω. Cm, which is far beyond the requirements of ordinary polymer insulator.
Test standard for volume resistivity of silicone rubber: GB / T 1692
Breakdown voltage strength
Breakdown voltage strength refers to the sudden change of dielectric from insulating state to conducting state when the electric field increases to a certain extent. It is a measure of the material's resistance to high voltage without producing dielectric breakdown, and its unit is kV / mm. During the test, place the sample between the electrodes and slowly increase the applied voltage through a series of steps until the electric breakdown occurs. Record the voltage strength at this time. The higher the breakdown voltage strength of the material, the better the quality of the material as insulator. As an excellent insulator material, the breakdown voltage strength of silicone rubber is generally 15 ~ 30KV / mm, which can meet most applications.
Test standard for dielectric strength of silicone rubber: GB / T 1695
Dielectric constant and dielectric loss tangent
Dielectric constant: the ratio of the capacitance of the capacitor with insulating material as the medium and vacuum as the medium, expressed by the letter ε. It shows the polarization degree of the material under the action of electric field. It needs a smaller ε when it is used as insulating medium and a larger ε when it is used as capacitor.
Tangent value of dielectric loss angle: the tangent value Tan δ of the residual angle δ of the phase angle between the applied voltage and the current of the same frequency when the sine wave voltage is applied to the dielectric. Its physical meaning is:
The smaller Tan δ is, the smaller energy loss is. Generally, the tangent value of loss angle of silicone rubber is less than 10-3.
Test standard for dielectric constant and dielectric loss tangent of silicone rubber: GB / T 1693
As the leading brand of silicone sealant industry, Baiyun chemical has rich experience in R & D and application in various fields, especially in the field of electrical equipment, and launched a number of indoor and outdoor component protection adhesives, such as:
1. Sma232 series for 4G antenna protection
Good electrical corrosion resistance, good insulation performance, long service life;
It has low surface energy, i.e. good hydrophobicity. Water drops can roll off at any time on the surface of silica gel, which is not easy to form conductive water film, so as to avoid electric shock;
Resistant to high and low temperature, acid and alkali. It can be used in different harsh environments for a long time.
2. Skf323 / skf452 series adhesive for power supply protection
Excellent flame retardant performance, UL certified, up to UL94V-0, no smoke or toxic gas will be emitted when burning;
It will not release small molecules after complete curing;
Widely used in all kinds of electronic and electrical components fixation and flame retardant, insulation, sealing and waterproof.
3. Smg261 glue for circuit board coating series
The transparency is good, and the components coated on PCB circuit board can be seen clearly;
One component, neutral room temperature curing, without heating, fast curing;
It has excellent waterproof, anti leakage and anti loose performance, good insulation;
It can be used in hybrid integrated circuit, automobile electronic control board, electronic circuit board, aviation instrument, soft printed circuit board, computer control board, industrial control board, semiconductor crystal circuit protection, home appliance controller, outdoor LED display screen;
As a new generation of polymer materials widely used, silicone rubber insulation materials will greatly promote the progress of silicone rubber technology with the rapid development of silicone industry in China, and the comprehensive performance of silicone rubber insulation materials will be further improved. In the face of new historical opportunities, Baiyun chemical will never forget its original mind, keep its mission in mind, grasp the needs of customers, strive to develop new products, always stay in the forefront of the industry, and dedicate the best products to mankind.
Author: BYOnline source: Guangzhou Baiyun Chemical Industry Co., Ltd
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