Magnesium oxide_magnesium hydroxide_magnesium carbonate manufacturer-Zehui Group
Magnesium hydroxide (Mg(OH)₂) primarily functions as a flame retardant, smoke suppressant, and safety enhancer in wire and cable sheaths. As an important inorganic flame-retardant additive, it is particularly suitable for scenarios with high environmental and safety requirements. Its specific roles are as follows:
The Role of Magnesium Hydroxide in Wire and Cable Sheaths
1. Efficient Flame Retardancy to Prevent Fire Spread
- Endothermic Cooling for Flame Retardancy: Magnesium hydroxide decomposes at high temperatures (2Mg(OH)₂ → MgO + 2H₂O↑), a process that absorbs a large amount of heat. This effectively lowers the surface temperature of the cable sheath, delaying the thermal decomposition and combustion rate of the material.
- Diluting Oxygen and Combustibles: The water vapor generated during decomposition dilutes the oxygen concentration around the cable and weakens the flammable gases produced by combustion, inhibiting the sustained burning of the flame and thus preventing the fire from spreading along the cable.
- Forming a Flame-Retardant Barrier: The magnesium oxide (MgO) produced after decomposition is a high-temperature-resistant inert solid. It forms a dense ceramic-like thermal insulation layer on the surface of the cable sheath, isolating heat and oxygen, further preventing the internal material from burning, and achieving a “self-extinguishing” effect.
2. Smoke Suppression and Toxicity Reduction to Lower Fire Hazards
- Reducing Smoke Generation: Compared with traditional halogenated flame retardants, magnesium hydroxide produces almost no toxic smoke or corrosive gases (such as hydrogen halides) during combustion. It significantly reduces smoke concentration in fires, minimizing secondary injuries caused by smoke asphyxiation or impaired visibility.
- Inhibiting Toxic Gas Release: Its decomposition products are water and magnesium oxide, both non-toxic and harmless substances. This avoids the release of toxic gases (such as carbon monoxide and cyanides) when the cable burns, improving safety at the fire scene.
3. Enhancing Material Mechanics and Environmental Adaptability
- Improving Sheath Mechanical Properties: As a filler, magnesium hydroxide can combine with the base materials of cable sheaths (such as polyethylene, polyvinyl chloride, rubber, etc.), enhancing the material’s hardness, tensile strength, and wear resistance, and reducing damage to the sheath during installation or use.
- Aging and Corrosion Resistance: Magnesium hydroxide has good chemical stability, resisting erosion from environmental factors such as acids, alkalis, and moisture. It delays the aging rate of the sheath material, extending the service life of the cable, especially in complex environments such as humid or outdoor settings.
4. Meeting Environmental and Compliance Requirements
- Halogen-Free and Environmental Characteristics: Magnesium hydroxide is a halogen-free flame retardant, containing no halogen elements such as chlorine or bromine. It complies with environmental regulations such as EU RoHS and REACH, avoiding the harm to the environment and human body caused by toxic and harmful substances generated during combustion of traditional halogenated flame retardants. It is suitable for green products such as low-smoke halogen-free cables.
- Adapting to Safety Standards: In fields with extremely high fire safety requirements such as construction, rail transit, and ships, using cable sheaths containing magnesium hydroxide can meet relevant flame retardant grades (such as UL94 V-0, IEC 60332, etc.), ensuring the safe operation of electrical systems.
Summary
Through multiple roles such as flame retardancy, smoke suppression, enhancing mechanical properties, and meeting environmental compliance, magnesium hydroxide has become an indispensable functional additive in wire and cable sheaths. Especially in application scenarios emphasizing halogen-free, low toxicity, and high safety, it effectively improves the fire protection capability and service life of cables, providing important guarantees for the safe and stable operation of electrical systems.
