With the improvement of people's living standards and fire safety awareness, as well as the rapid growth of urban population, flame retardant and refractory materials are playing an increasingly important role in many areas of national production and life. Silicone rubber has unique chemical stability, high and low temperature resistance, weather resistance and insulation properties. At the same time, it has less smoke and non-toxicity during combustion, low combustion heat value, and slow flame propagation speed, making it suitable for aerospace, electronic appliances, and power transmission. And other fields have been widely used.
Due to the high bond energy of the Si-O bond in silicone rubber, the silicone rubber itself has good thermal stability. In addition, when burned under a high-temperature flame, the Si-O bond will transform into a continuous, oxidation-resistant, and insulating network. Silica-like silicon dioxide SiO2 ash covers the surface, which effectively prevents further ablation. In addition, the flue gas produced during the combustion of the silicone rubber matrix is mainly CO2 and H20 produced by the combustion of the side chain groups. It does not produce toxic gases and will not pollute the environment. The use of silicone polymers to prepare ceramic flame-retardant refractory materials has unique advantages in terms of process and raw material selection, as well as the high temperature resistance and mechanical properties of ceramic products.
Ceramic fire-resistant silicone rubber is a new type of fire-resistant material. It is a fire-resistant and flame-retardant material prepared by adding inorganic mineral powder fillers, structure control agents and other additives to the silicone rubber matrix. This material has general characteristics at room temperature. The excellent performance of the polymer can form a hard ceramic protective layer when it encounters high temperature or flame burning, and it can form a hard ceramic protective layer, which can isolate the flame and prevent fire, thus ensuring the normal power and communication in the event of a fire. jobs.
2. Characteristics of ceramicized refractory silicone rubber:
1 Form a self-supporting ceramic body in the flame
When rubber materials containing inorganic fillers are exposed to flames, the rubber will be degraded or burned. After the degradation or combustion products volatilize, inorganic residues or ash with less strength will be left behind. These residues are usually not agglomerated or self-supporting, and even broken into granules or powder, so they have no fire protection effect. When specially designed and formulated ceramized rubber is exposed to flame, depending on the rubber type and formula adjustment, it can be ceramized in the range of 500～800℃ or above, and sintered into a porous self-supporting ceramic body, in a certain period of time (0.5 ～2h) The integrity of the structure can be maintained, and the effect of "passive fire protection" can be brought into full play, and valuable time can be gained for fire safety.
2 Has a certain strength, good thermal shock resistance
The sintered body after ceramization is relatively hard, has a ceramic sound when it is knocked, and has a certain flexural strength and press-through strength. The bending strength of the ceramized silicone rubber specimen is much greater than that of ordinary silicone rubber, and it increases significantly with the increase of temperature. The fire-fighting process is simulated by spraying water on the high-temperature ablated test piece, and the sintered body of ceramized silicone rubber does not burst, showing good thermal shock resistance.
3 Halogen-free, low smoke, low toxicity, self-extinguishing, environmental protection
Ceramic fire-resistant silicone rubber can achieve flame-retardant and self-extinguishing effect without adding halogen flame retardants. The flame retardancy is UL94V-0 and the oxygen index can be as high as 38. Under the ablation of the flame, the smoke was completely cut off after being burned for a few minutes. In the subsequent ablation process, no more smoke was produced by itself. The combustion of ceramic silicon rubber produces carbon dioxide, water and silicon dioxide, all of which are non-toxic substances.
4 Good electrical performance
The electrical properties of the optimized ceramic silicone rubber—the volume resistivity before sintering is not less than 1015Ω•cm. As the sintering temperature increases, the volume resistivity decreases. After burning at 1000℃ for 30 minutes, the volume resistivity decreases. It is 107Ω•cm.
5 Easy to process
The production equipment of ceramicized fire-resistant silicone rubber is the same as that of ordinary silicone rubber. The rubber compound has good extrusion performance and molding performance. It can be directly extruded and vulcanized into wires and cables with silicone rubber wire and cable equipment without additional equipment. The production process of the fire-resistant cable is simplified and the cost is reduced.
Third, the application of ceramic fire-resistant silicone rubber
Ceramic fire-resistant silicone rubber has rubber elasticity at room temperature. After fire, it will not become brittle and fall off like mica tape. It can pass spray and vibration tests. Considering that the major fires in many major civil buildings in my country in recent years are related to wires and cables, there is a great demand for fire-resistant cables for civil buildings. At present, ceramic silicon rubber will be widely used and developed in medium and low-voltage fire-resistant cables.
When ceramicized fire-resistant silicone rubber is used as a firewall, it can form a refractory ceramic layer under high-temperature flames to prevent flame penetration. The use of flame-retardant ceramicized silicone rubber firewalls in aircraft can prevent flames from spreading in the cabin.
In addition, it has other very wide applications, such as fire doors, fire boards, building fire-proof coatings, fire-proof high-temperature treatment materials, high-temperature fire-insulation layers for rocket launch platforms, etc.
Four, typical product data
Five, use method and operation
1. Start mixing on an open mill for about 3-5 minutes, so that the rubber can be rolled and mixed evenly.
2. Add color paste and mix evenly (if necessary), then add vulcanizing agent, hit ten to fifteen rolls, so that the vulcanizing agent is evenly dispersed in the rubber, and the surface of the rubber becomes smooth.
3. Lower the roll and eject the film. Separate the two pieces with adhesive paper.
The curing temperature is 170℃-350℃, and the specific setting is determined according to the equipment, extrusion speed and cable specifications.
Security and storage
* From the date of production, it should be stored at room temperature for six months; it is recommended to use it within three months. If it exceeds three months, the product mixing time should be appropriately extended.
* Please wear protective glasses and gloves when operating this product.
* Store in a dry and cool place, away from direct sunlight.
* Keep out of reach of children.
* Before use, please read the product instructions and product safety data sheet carefully.
* Packed in 20KG carton, lined with plastic bag.
Instructions for industrial use
1. The user is obliged to understand the scope of application and use of the product.
2. The inspection report we shipped with the goods is only based on the vulcanization conditions and testing methods of Dongguan Langsheng Material Technology Co., Ltd. It cannot be used as the standard for the silicone rubber compound of Dongguan Langsheng Material Technology Co., Ltd., and cannot be accepted as a customer. Acceptance basis of Sheng Material Technology Co., Ltd. products.
3. Due to the different testing and production conditions, we cannot guarantee that both parties can get the same test results. It is recommended that users use the data tested under their own testing conditions as a reference for performance.
4. Any of the above performance data and applicable suggestions are only a reference for the performance of the products of Dongguan Langsheng Material Technology Co., Ltd., and not a guarantee for the effectiveness or generality of Dongguan Langsheng Material Technology Co., Ltd. under a specific application.
5. We reserve the right to change the product data, if there is any change, without notice.