In recent years, new types of refractory materials – ceramic refractory silicone rubber and ceramic refractory silicone rubber composite belt are used in the production of refractory cables, which basically solve the problems of the above two kinds of refractory cables.
1. Characteristics of ceramic refractory silicone rubber
Ceramic refractory silicone rubber is made by adding functional materials to high temperature heat vulcanization (HTV) silicone rubber. High and low temperature resistance, ozone aging resistance, weather aging resistance, excellent electrical insulation performance and good processing performance; under high temperature flame ablation, the silicone rubber composite mixture added with functional materials forms a hard ceramic armor protective layer, It can play the role of flame isolation, fire prevention, insulation, heat insulation, water insulation and earthquake resistance, thus ensuring the smooth flow of electricity and communication in case of fire.
2. The mechanism of fire resistance and fire resistance of ceramic refractory silicone rubber
Ordinary polymer materials are turned into ashes after flame ablation, and cannot be turned into ceramic objects; ceramic fireproof and refractory silicone rubber can be sintered at a flameless high temperature above 500 °C and flame ablation above 620 °C. The longer the ablation time and the higher the temperature, the more obvious the ceramization effect is, and the ablation temperature can reach up to 3000 ℃; ceramicized fire-resistant and refractory silicone rubber can be produced using conventional rubber processing equipment. The finished product has all the properties of silicone rubber and has good processability.
It is a composite material that can be porcelainized at high temperature by adding silicone rubber. It maintains all the characteristics of silicone rubber at room temperature. When encountering flameless high temperature above 500 ℃ and flame ablation above 620 ℃, it will be transformed into inorganic ceramics. This kind of ceramic material has the advantages of ceramic insulation, heat insulation, fire insulation, water insulation, shock resistance, and small thermal weight loss.
Ceramic fire-resistant and refractory silicone rubber is non-toxic and odorless at room temperature, has good softness and elasticity, and excellent moisture resistance and water absorption resistance. It has the characteristics of silicone rubber. Ceramic refractory silicone rubber can be burned by flames After burning for 2-4 minutes, it starts to sinter into a hard ceramic-like armored shell. The insulating layer of this hard ceramic-like armored shell can effectively prevent the flame from continuing to burn; and it is completely broken after being burned for about 2 minutes. Smoke, in the next ablation process, no smoke itself will be generated; the smoke generated within the first 2 minutes is also halogen-free, non-toxic, and harmless; the smoke is mainly solid smoke generated after the combustion of organic silicon, The burnt ceramic-like material is a hard and uniform honeycomb shell. Such an object has excellent insulation, heat insulation, fire resistance and fire resistance, and can also withstand shock and vibration, and prevent water infiltration. It ensures the smooth flow of the line in the case of spraying and vibration.
Ceramic refractory silicone rubber composite belt
The ceramic refractory silicone rubber composite tape is made by attaching ceramic fire-resistant and refractory silicone rubber to the high-temperature-resistant glass fiber cloth according to a certain thickness through the bonding process, after cutting, and wrapping it on the fire-resistant and refractory wire and cable.
Characteristics of ceramic refractory silicone rubber and ceramic refractory silicone rubber composite belt:
1. Excellent electrical insulation: can reach the electrical properties of XLPE and EPDM: volume resistivity can reach 2×1015Ω·cm, breakdown strength 22-25KV/mm, dielectric loss tangent 10-3, dielectric constant δ: 2-3.5, can be used for insulation;
2. Excellent high and low temperature resistance: long-term working temperature -70~200°C, service life can reach 5-50 years according to different environmental conditions; it starts to harden above 350°C, and can be used for a long time in a static environment;
3. Resistance to ozone and ultraviolet rays: no need to add anti-aging agents and antioxidants, and the service life can reach more than 30-50 years at room temperature;
4. Special surface properties: water absorption rate 0.17%, with extremely low hygroscopicity and water absorption, good anti-mildew performance, non-stick to many materials;
5. Environmentally friendly: halogen-free, heavy metal-free, non-toxic, tasteless, and has no impact on the human body and the environment;
6. Good chemical corrosion resistance, waterproof and oil resistance;
7. Excellent hydrophobicity, pollution flashover resistance and creepage resistance;
8. Good processing performance: easy to process such as mixing, forming, calendering, extrusion, molding, etc., and the fluidity of the rubber material is good;
9. Smoke toxicity is currently the highest grade ZA1 among polymer materials, especially cable materials, that is, the smoke after combustion is inhaled by mice for 30 minutes, and there is no change within three days;
10. Good heat insulation, thermal conductivity 0.09W/Mk, especially after ablation, the interior is a uniform honeycomb shape, which has better fire resistance and heat insulation;
11. Good flame retardancy: the flame retardancy can reach UL94V-0 level, the oxygen index is above 28, and the highest can reach above 40.5;
12. After high-temperature combustion, it can be fired into a ceramic shape to form a hard ceramic armor to protect the smooth flow of the circuit. This is the most “revolutionary” feature of ceramic fire-resistant and refractory silicone rubber. The higher the temperature, the longer the ablation time, and the ceramic armor The harder the body; it is better than the mica tape, which becomes hard and brittle after burning and falls off easily;
13. The fire-resistant and fire-resistant wire and cable produced by ceramic fire-proof and fire-resistant silicone rubber and ceramic fire-proof and fire-resistant silicone rubber compound tape can reach the A-level standard of GB12666.6, that is, burn in a flame of 950~1000℃ for 90min, 3A fuse No fusing; it can also reach the highest level of C W Z of the British BS6387, that is, C—burning in a flame at 950°C for 3 hours, W—water spray, Z—vibration;
14. Small density (1.42-1.45), low price and high cost performance;
15. Based on the above characteristics, it can completely replace mica tape, not only for low-voltage fire-resistant and fire-resistant cables, but also for medium and high-voltage fire-resistant and fire-resistant wires and cables.
Post time: Mar-20-2023