Introduction to silicone foam
Silicone foam material (also known as: silicone foam / foamed silica gel) is a porous, low density, compressible polymer elastomer made of silicon rubber, filler, vulcanization accelerator, styrofoam, etc. as raw materials, mixed uniformly, and then made by a special process under high pressure and high temperature. Because of the high elasticity of silicone rubber, and the sound insulation, shock absorption and other properties of foam materials, it is widely used in life, mostly used as vibration damping gasket, sealing gasket, sound absorbing material, insulation layer material, airline insulation material. According to the cell structure, silicone foam is divided into three types: closed-cell type, open-cell type and mixed type.
Closed-cell foamed silicone foam material has the characteristics of good shockproof cushioning, sound insulation, heat insulation and flame retardant explosion-proof, and it is mainly used in the automotive field for heat insulation foam pipes for automotive car air conditioners, automobile shock absorption, and foamed silicone sealing gaskets for new energy vehicle batteries. The interior materials of many automobiles today, such as floors, ceilings, steering wheels, car seats, etc., are polyurethane foam materials, on the one hand, because the technology of polyurethane foam materials is relatively mature, and the performance meets the use standards; On the other hand, it is because of the lower price of polyurethane foam materials. However, polyurethane foam materials have poor weather resistance, are flammable and release a large number of toxic gases harmful to the human body during combustion. Therefore, with the promotion of silicone foam materials and the improvement of people's awareness, silicone foam materials are expected to replace traditional polyurethane foam foam materials in the future.
Properties of silicone foam
The density of silicone foam
The density of the silicone foam matrix is 1.17g/cm3. However, through foaming treatment, the density of silicone foam materials prepared in the current mature process can be as low as 0.16-0.20 g/cm3, which can be used for car seats, headrests and other components; Conventional silicone rubber foam materials (density 0.45 g/cm3) are widely used for gap filling in sealing, shock absorption and other parts.
Flame retardant properties of silicone foam
According to scientific experimental research data, silicone foam with flame retardant has good flame retardant performance, and the flame retardant grade can reach UL94-V0, which can be applied to electric vehicles, which can well reduce problems caused by combustion.
Electrical insulation properties of silicone foam
With the increase of the amount of physical filler, the volume resistivity and surface resistivity of silicone rubber showed a decreasing trend, and the dielectric constant and dielectric loss factor showed an overall increasing trend. It can be seen that the addition of physical filler damages the electrical insulation properties of silicone rubber to a certain extent.
Application of silicone foam in electric vehicle industry
The battery cell is the source of kinetic energy of pure electric vehicles, the safety hazards of the battery cell seriously endanger the safety of the whole vehicle, the battery cell will produce a certain amount of heat when working, and can produce a certain thermal expansion and contraction effect at different temperatures, resulting in a certain expansion of the cell, long-term grid friction between the cells, which is likely to cause damage to the battery resulting in ineffective rechargeable batteries, and even uncontrollable in severe cases. In addition, the output voltage of the battery pack reaches above 200V, and it is stipulated that the rechargeable battery shell must be sealed and waterproof to avoid short circuit caused by water seepage, and the waterproof level of the rechargeable battery shell is specified to be IP67.
Silicone foam has high reduction characteristics, avoids deformation caused by thermal expansion and contraction of rechargeable battery cells in the whole process of battery charging, charging and discharging, and has excellent durability, low reduction, impact digestion and absorption and flame retardancy (UL 94 V0 grade). At the same time, silica gel also has good waterproof performance, as well as the following properties, so it is widely used in the buffer insulation of new energy cells and the sealing of the outer frame.
1. At different temperatures, the performance of silicone foam is stable, and the performance of the product sealing ring is stable 2. Excellent waterproof sealing, no water penetration when the goods are used out3. Long-term reduction damage is small, and there is a certain working ability to curb shrinking deformation 4. Excellent flame retardant performance, which can effectively prevent the risk caused by thermal effects in battery work 5. Thickness and strength can be designed according to different standards, and the sealing ring must be well matched with the shell and low internal stress. It can effectively avoid the application of the sealing ring bending and arching silicone foam gasket in the outer frame sealing of new energy power lithium batteries.
For silicone foam, please check the details:
https://www.siliconefoam.net/product-firm-cellular-silicone-iota-ht-820-.html
