Properties of silicone rubber foam material (foamed silicone rubber)

Silicone rubber foam is widely used. Because of its excellent properties of silicone rubber and foam material, it has the properties of high resilience, aging resistance, and sound absorption, shock absorption and other foam properties. It is mainly used for waterproof, shock absorption, sealing gaskets (sealing grade IP68), sound insulation, insulation, Aviation insulation and other properties. Find a higher case. According to the bubble structure, silicone rubber foam is divided into three types: closed, open and mixed.

Closed cell foaming silicone foam materials have better shockproof cushioning, sound insulation, heat insulation and flame retardant and explosion-proof properties. They are mainly used in automotive field for insulation foam tube for automotive air conditioning, automotive shock absorption, foaming silicone seal gaskets for new energy vehicle batteries, etc.

At present, most automotive interior materials, such as flooring, ceiling, steering wheel, car seat and so on, are polyurethane foam materials. This is because the technology of polyurethane foam is relatively mature, and its performance meets the needs of use. On the other hand, the price of polyurethane foam is low. However, polyurethane foam has poor weatherability and flammability and releases a lot of toxic gases harmful to human body during combustion. Therefore, with the popularization of foamed silica gel materials and the improvement of people's understanding of them, the future foamed silica gel materials are expected to replace traditional polyurethane foaming materials.

Density Selection of 1 Foamed Silica Gel
The density of silicone rubber matrix is 1.17g/cm3. However, through foaming treatment, the density of silicone rubber foam material produced in the current mature process can be 0.16-0.20 g/cm3, which can be used for car seat and headrest. While conventional silicone rubber foam material (density of 0.45 g/cm3) is widely used in sealing, shock absorption and other parts of the gap filling.

Flame Retardant Properties of 2-Foamed Silica Gel
Vertical combustion method is often used to characterize the flame retardancy of polymers. Its combustion mode is very close to the actual situation of object combustion, so it can well reflect the actual flame retardant effect of silicone rubber. The effect of flame retardant dosage on the vertical combustion performance of silicone rubber is shown in Table 2. From Table 2, it can be seen that silicone rubber without flame retardant burns completely; silicone rubber with 40 phr of flame retardant reaches FV-1 grade and has certain self-extinguishing ability; silicone rubber with 80 phr of flame retardant reaches FV-0 grade, showing good self-extinguishing ability.

Electrical Insulation Properties of 3-Foamed Silica Gel
With the increase of the amount of physical filler, the volume resistivity and surface resistivity of silicone rubber decrease, while the dielectric constant and dielectric loss factor increase. It can be seen that the electrical insulation properties of silicone rubber are damaged to a certain extent by adding physical fillers.