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With the progress and development of modern science and technology, the use of silicone rubber in medicine will have broader prospects.

Foam silicone rubber is based on condensation-type hydroxy-terminated silicone rubber as the base material, hydroxy hydrogen-containing silicone oil as the blowing agent, vinyl platinum complex as the catalyst (heated catalyst is dibutyl tin dilaurate), in A sponge-like elastomer with holes formed by foaming and vulcanization at room temperature. In order to improve the quality of the foam, some other components must be added, such as silicone oil, so that the vulcanization process generates more gas; improve the feel of the foam and reduce the density. The addition of diphenyl silicon diol can not only control the structure of the foam, but also control the viscosity increase of the rubber compound during storage, but its amount should not be too much, otherwise it will affect the electrical properties of the foam. In order to improve the physical and mechanical properties of the foam, transparent silicone rubber can also be added. The amount of the chloroplatinic acid vinyl complex of the catalyst should not be too much, which is convenient for operation, otherwise it will increase the viscosity and is not conducive to the operation; when the amount of the catalyst is insufficient, the vulcanization is incomplete, the foam surface is sticky, and the elasticity is not Good, soft and plastic with poor strength.

Foam silicone rubber is liquid before vulcanization, suitable for potting material. The foam after vulcanization can be used for a long time at -60 ~ 159 ℃, after 150 ℃, 72 hours old, or a 60 ~ ten 70 ℃ ten times cold and hot alternating use, the foam still maintains the original performance.

Foam silicone rubber has high thermal stability, good thermal insulation, insulation, moisture resistance, and shock resistance, especially good vibration resistance at high frequencies, so it is an ideal lightweight packaging material. It is used for various electronic components, instruments, instruments, flight instrument wheels, etc. It can play the role of "three protection" protection against moisture, shock, and corrosion. In addition, it can also be used as a filling material for thermal insulation interlayer and float in a salt fog atmosphere. Materials and sealing materials. Foamed silicone rubber can also be used as a filling, repairing and clothing material for orthopedic surgery in medicine.

In order to meet the fire protection requirements of transmission lines, flame retardant room temperature vulcanized foam silicone rubber DC3-6548 was developed. This kind of foamed silicone rubber is mainly used for fireproof sealing of wire and cable passages (such as holes in roofs, walls, buildings, etc.). The flame retardant performance is very good. Its limiting oxygen index is 39 (most plastics have a limiting oxygen index of only 20. ), With a service life of up to 50 years. This flame-retardant room temperature vulcanized foamed silicone rubber has been widely used in nuclear power plants, electronic computer centers, offshore oil production equipment and other harsh environmental conditions, or places with particularly high fire requirements.

Two-component condensation type room temperature vulcanized silicone rubber Two-component condensation type room temperature vulcanized silicone rubber is the most common type of room temperature vulcanized silicone rubber. Its raw rubber is usually hydroxyl-terminated polysiloxane, and then combined with other complexing agents and catalysts. Combined to form a compound, the viscosity of this compound can range from 100 centistokes to one million centistokes.

Two-component room temperature vulcanized silicone rubber vulcanization reaction is not initiated by moisture in the air, but by the catalyst. Generally, the silicon raw rubber, filler, and cross-linking agent are packaged as one component, and the catalyst is packaged as another component alone, or in other combinations, but the catalyst and cross-linking agent must be packaged separately. Regardless of the packaging method used, curing only begins when the two components are completely mixed together. The commonly used cross-linking agent is ethyl orthosilicate and the catalyst is dibutyltin dilaurate. And add appropriate fillers and additives according to the nature of the desired final product. In many countries, dibutyltin dilaurate is a medium-toxic substance. It is forbidden to add dibutyltin in food bags and plasma bags, which has basically been replaced by low-toxic octyltin.

The curing time of the two-component condensation type room temperature vulcanized silicone rubber mainly depends on the type, amount and temperature of the catalyst. The more the amount of catalyst, the faster the sulfidation, and the shorter the shelving time. At room temperature, the shelving time is generally a few hours, if you want to extend the shelving time of the rubber, you can use the cooling method. Two-component condensation type room temperature vulcanized silicon rafters need about one day to fully cure at room temperature, but only need 1 hour at 150 ℃. The synergistic effect of the accelerator γ-aminopropyltriethoxysilane can significantly increase the curing speed.

Two-component room temperature vulcanized silicone rubber can maintain elasticity for a long time within a temperature range of 65 ~ 250 ℃, and has excellent electrical properties and chemical stability, water resistance, ozone resistance, weather resistance, combined with simple usage, strong process applicability Therefore, it is widely used as potting and molding materials. Various electronic and electrical components are coated and potted with room temperature vulcanized silicone rubber, which can protect against moisture (anticorrosion, shockproof, etc.). It can improve performance and stabilize parameters. Two-component room temperature vulcanized silicone rubber is particularly suitable for deep filling The sealing material has a faster vulcanization time, which is superior to the single-component room temperature vulcanized silicone rubber.