From environmental protection to flame retardant: How does magnesium hydroxide reshape the cable industry?
Driven by the global energy transformation and the "dual carbon" goals, the cable industry is undergoing a revolution from material innovation to functional upgrading. Among them, magnesium hydroxide (Mg(OH)₂) has become a key material to ｒｅｐｌａｃｅ traditional flame retardants with its unique environmental protection properties and efficient flame retardant properties. This article will analyze how magnesium hydroxide can promote the transformation of the cable industry towards green and safe directions from three dimensions: technical principles, application scenarios, and market trends.
1. The environmental advantages of magnesium hydroxide: solving the pollution problem of traditional flame retardants
1.1 The dilemma of traditional flame retardant materials
For a long time, the cable industry has relied on brominated flame retardants (such as decabromodiphenyl ether) and halogen-containing compounds to achieve flame retardant effects. However, these materials will produce toxic gases such as dioxins and hydrogen halides when burned, which not only threatens human health, but also causes soil and water pollution. The introduction of regulations such as the EU "RoHS Directive" and China's "Guidelines for the First Batch Application Demonstration of Key New Materials" has further restricted the use of highly polluting flame retardants.
1.2 Green breakthrough of magnesium hydroxide
As an inorganic flame retardant, magnesium hydroxide has the following core advantages:
- Non-toxic and environmentally friendly: only water vapor (H₂O) is released when decomposed at high temperature, and no harmful gas is produced;
- Degradability: the material can be returned to the environment through natural hydrolysis after being discarded, which is in line with the concept of circular economy;
- Raw materials are easy to obtain: mainly extracted from seawater or minerals, and the cost is only 60%-70% of traditional flame retardants.
According to the "2023 Global Flame Retardant Market Report", the application growth rate of magnesium hydroxide in the cable field reached 12.3%, far exceeding the industry average (5.8%).
2. Analysis of flame retardant mechanism: How magnesium hydroxide improves cable safety
2.1 Scientific principles of flame retardant effect
The flame retardant properties of magnesium hydroxide are derived from its unique physical and chemical properties:
1. Endothermic decomposition: At high temperatures of 340°C-490°C, magnesium hydroxide decomposes into magnesium oxide (MgO) and water, absorbing a large amount of heat (heat absorption of 44.8 kJ/mol), reducing the surface temperature of the material;
2. Diluting oxygen: The released water vapor can dilute the concentration of combustible gases and inhibit the combustion chain reaction;
3. Forming a protective layer: The generated magnesium oxide covers the surface of the material, isolating oxygen and preventing the spread of flames.
2.2 Performance optimization technology
In order to improve the compatibility of magnesium hydroxide in cables, the industry adopts two major technical paths:
- Surface modification: Through the treatment of coupling agents such as silane and titanate, the interfacial bonding between magnesium hydroxide and polymer matrix (such as polyethylene, PVC) is enhanced;
- Nano-processing: The magnesium hydroxide particles are refined to 50-100 nanometers, the flame retardant efficiency is increased by more than 30%, while maintaining the flexibility of the cable.
Experimental data show that the limiting oxygen index (LOI) of polyethylene cables with 40% nano magnesium hydroxide added increased from 17% to 32%, reaching the UL94 V-0 flame retardant standard.
3. Application scenarios: comprehensive penetration from power transmission to new energy infrastructure
3.1 High-voltage power cables
In UHV power transmission projects, cables need to withstand long-term high-temperature operation. The magnesium hydroxide flame retardant layer can significantly improve the temperature resistance level of cross-linked polyethylene (XLPE) insulation materials. For example, the 125kV high-voltage cable used by the State Grid in the "West-to-East Power Transmission" project has a flame retardant layer with a magnesium hydroxide addition of 55%, reducing the fire risk by 76%.
3.2 New energy field
- Photovoltaic cables: Magnesium hydroxide is combined with EVA film to enable the components to pass the IEC 62930 fire protection certification at a system voltage of 1500V;
- Electric vehicle charging piles: Flame-retardant cables with magnesium hydroxide added can remain non-melting for 2 hours under arc impact, ensuring charging safety.
3.3 Smart building scenarios
In high-rise buildings, magnesium hydroxide flame-retardant cables are used in fire emergency systems. Its low smoke characteristics (smoke density <15) ensure that the visual distance of personnel evacuation channels increases by more than 3 times when a fire occurs.
IV. Market prospects: a 100 billion track driven by policy and technology
4.1 Policy dividend release
China's "14th Five-Year Plan for New Infrastructure Construction" clearly requires the elimination of halogen-containing flame-retardant cables by 2025, which will bring an average annual market increase of 800,000 tons for magnesium hydroxide. The EU's "Green Agreement" stipulates that all new buildings must use halogen-free flame-retardant materials before 2030.
4.2 Technological innovation trends
- Compounding technology: magnesium hydroxide is used in conjunction with expanded graphite and nanoclay to increase the flame retardant efficiency to 70%;
- Intelligent production: AI algorithms optimize the particle size distribution of magnesium hydroxide, increasing the cable extrusion molding speed by 22%.
According to Grand View Research, the global magnesium hydroxide flame retardant market size will grow from US$980 million in 2023 to US$2.14 billion in 2030, with a compound annual growth rate of 11.7%.
5. Challenges and Solutions
Despite the broad prospects, the application of magnesium hydroxide still faces two major challenges:
1. Excessive filling amount: The traditional process requires the addition of 50%-65% of magnesium hydroxide to meet the standard, which may affect the mechanical properties of the cable;
2. Uneven dispersion: Particle agglomeration causes local flame retardant failure.
The industry is breaking through the following solutions:
- Developing core-shell structure materials: With magnesium hydroxide as the core and coated with silicone shell, the filling amount can be reduced to 35%;
- Supercritical fluid dispersion technology: Using CO₂ supercritical state to achieve uniform distribution of nanoparticles.
From environmental compliance to performance upgrades, magnesium hydroxide is redefining the technical standards of the cable industry. With the continuous breakthroughs in preparation technology and the application scenarios