Cable material halogen-free: magnesium hydroxide meets TUV flame retardant standards
With the continuous improvement of environmental awareness, cable materials are developing towards a greener, safer, and more sustainable direction. Among them, "halogen-free" has become one of the important trends in the cable material industry.
Among numerous halogen-free flame retardant materials, magnesium hydroxide has gradually become an ideal choice to ｒｅｐｌａｃｅ halogenated flame retardants due to its excellent flame retardant properties and environmentally friendly characteristics. Especially in meeting TUV flame retardant standards, magnesium hydroxide has demonstrated significant advantages, providing more reliable technical support for the cable industry.
1、 Why do cable materials need to be halogen-free?
Cables are widely used in fields such as construction, power, communication, and rail transit, and their safety is directly related to public safety. Bromine or chlorine flame retardants are often added to traditional cable materials. Although these halogenated materials can effectively suppress combustion, once a fire occurs, they will release a large amount of toxic halogenated gases and thick smoke at high temperatures, which not only cause great harm to human health, but also affect the efficiency of escape and rescue.
Based on this, higher requirements have been put forward internationally for the environmental protection and safety performance of cables. For example:
The EU RoHS directive restricts the use of hazardous substances;
The IEC 60754 standard specifies the amount of halogen gas released during cable combustion;
The TUV certification system takes the flame retardant performance and low smoke and non toxicity of cables as the core evaluation indicators.
In this context, the "halogen-free" transformation of cable materials is imperative.
2、 Magnesium hydroxide: representative of environmentally friendly flame retardants
Magnesium hydroxide (Mg (OH) ₂) is a white powdery inorganic compound with good thermal stability and flame retardant effect. It absorbs a large amount of heat and releases water vapor during thermal decomposition, thereby playing a role in cooling and diluting combustible gases. Meanwhile, its decomposition product is magnesium oxide, which does not produce toxic gases and conforms to modern environmental protection concepts.
1. The flame retardant principle is clear and effective
The flame retardant effect of magnesium hydroxide is mainly reflected in three aspects:
Heat absorption and cooling: Within the temperature range of 250-350 ℃, magnesium hydroxide begins to dehydrate and decompose, absorbing a large amount of heat and reducing the surface temperature of the material.
Dilute oxygen: The released water vapor can dilute the oxygen concentration in the combustion zone and suppress flame spread.
Forming a protective layer: The decomposed magnesium oxide adheres to the surface of the material, forming a dense carbonized layer that further isolates oxygen and heat.
This dual flame retardant mechanism of physics and chemistry enables it to exhibit stable fire resistance in cable materials.
2. Environmentally friendly and non-toxic, in line with development trends
Magnesium hydroxide does not contain any halogen components and does not release toxic gases or black smoke during combustion, meeting the current global requirements for "green building materials" and "low smoke and halogen-free" products. In addition, its wide range of raw material sources and relatively moderate prices also enhance its feasibility in industrial applications.
3、 How to meet TUV flame retardant standards?
TUV is a strict cable testing and certification system developed by the German Technical Supervision Association (T Ü V), widely used in European and international markets. For cable materials, TUV certification means that the product meets high standards in terms of flame retardancy, fire resistance, low smoke and non-toxic properties.
1. Flame retardant grade meets the standard
The TUV standard has clear requirements for vertical combustion testing (such as IEC 60332-1) and bundled combustion testing (IEC 60332-3) of cables. Magnesium hydroxide as the main flame retardant, combined with other functional additives, can easily pass these tests for cable materials.
2. Good smoke density control
The TUV standard stipulates that the smoke generated during cable combustion should not be too thick to ensure visibility at the fire scene. Magnesium hydroxide releases water vapor during combustion, with extremely low smoke density, fully meeting TUV's requirements for low smoke performance.
3. The halogen content test is qualified
TUV certification explicitly prohibits the use of halogen flame retardants. Magnesium hydroxide itself does not contain halogens and does not generate halide gases after cable combustion, so it can smoothly pass halogen content testing to ensure product certification qualifications.
4、 The practical application of magnesium hydroxide in cable materials
At present, magnesium hydroxide has been widely used in various types of cable materials, especially in the following categories of products:
1. Low smoke halogen-free flame retardant polyolefin (LSZH)
This is currently the most mainstream environmentally friendly cable sheath material. Magnesium hydroxide, as the main flame retardant filler, can endow materials with excellent flame retardant properties and mechanical strength, while maintaining good processability.
2. Cables for rail transit
Subway, high-speed rail and other transportation vehicles have extremely high safety requirements for cables, which must have good flame retardant, low smoke, and non-toxic characteristics. The cable material modified with magnesium hydroxide has been successfully applied in multiple urban rail transit projects.
3. Building electrical wiring
In residential and office buildings, the safety performance of electrical wiring directly affects personal safety. More and more wire manufacturers are choosing magnesium hydroxide as a flame retardant to meet the new national standards and consumers' demand for a healthy living environment.
The halogen-free process of cable materials is not only a reflection of technological progress, but also a fusion of social responsibility and environmental protection concepts. Magnesium hydroxide, as an efficient and environmentally friendly halogen-free flame retardant, not only meets TUV flame retardant standards, but also brings higher safety levels and market competitiveness to the cable industry.