Properties and applications of inorganic low smoke halogen-free flame retardants
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First, performance characteristics
Environmentally friendly and non-toxic
It does not contain halogen, does not release toxic gases (such as hydrogen halide, dioxins, etc.) during combustion, meets the requirements of environmental protection regulations, and is suitable for areas with strict environmental protection requirements.
Low smoke, no halogen
Low smoke generation during combustion, reducing the harm to personnel and equipment during fire, especially suitable for confined Spaces or crowded places.
High thermal stability
The decomposition temperature is high (such as the decomposition temperature of aluminum hydroxide is about 200-300 ° C, and magnesium hydroxide is about 340-490 ° C), which can still maintain the flame retardant effect under high temperature environment.
High flame retardant efficiency
By absorbing heat, diluting combustible gas, forming carbonization layer and other mechanisms, the flame can be effectively prevented from spreading.
Synergistic effect
It can be combined with other flame retardants (such as phosphorus, nitrogen) to improve the flame retardant efficiency and reduce the amount of a single flame retardant.
Mechanical properties have little effect
Some inorganic flame retardants (such as nano silica, silicate) can enhance the mechanical properties of the material, such as strength, toughness, etc.
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Second, the main use
Wire and cable
Instead of halogenated flame retardants, it is used in power cables, communication cables, data cables, etc., to improve fire safety and reduce the release of toxic smoke during fire.
Building material
Used for fire-proof board, insulation materials, wall materials, etc., to improve the fire rating of buildings and meet the building safety code.
Electronic appliance
As a flame retardant filler for circuit boards, shells, connectors and other materials, to prevent the release of toxic gases during electrical fires and ensure personnel safety.
transportation
It is used in the interior materials, seats, wires and cables of vehicles such as automobiles, high-speed railways and aircraft to improve the fire safety of vehicles.
textile
Used for fireproof clothing, curtains, carpets, etc., to reduce the release of smoke and toxic gases during fire and protect personnel safety.
Other fields
It can also be used in aerospace, military equipment, new energy batteries and other fields to meet the strict requirements for fire prevention and environmental protection.
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Third, common types of inorganic low-smoke halogen-free flame retardants
hydroxides
Aluminum hydroxide (ATH), magnesium hydroxide (MDH) : endothermic decomposition, release of crystal water, form aluminum oxide/magnesium oxide coating, isolation of oxygen.
Borates
Zinc borate (ZB) : both flame retardant, smoke suppression, anti-drip function, often combined with other flame retardants.
Metal oxides
Antimony trioxide (Sb₂O₃), magnesium oxide (MgO), alumina (Al₂O₃) : as a synergist or direct flame retardant, to improve the flame retardant properties of the material.
Silicon-based flame retardant
Silicates (such as montmorillonite, kaolin), nano-silica (SiO₂) : form a physical barrier, isolate heat and oxygen, and enhance the carbonization of materials.
Phosphorus based inorganic flame retardants
Red phosphorus, ammonium polyphosphate (APP) : When burned, phosphoric acid is generated to promote carbon formation and isolate oxygen.
other
Expandable graphite (EG), zinc stannate, ammonium molybdate, etc. : Through expansion, heat absorption, synergistic flame retardant and other mechanisms to improve the fire performance of materials.
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Fourth, application advantages
High safety: reduce the release of toxic smoke and gas during fire and reduce the risk of casualties.
Strong environmental protection: in line with RoHS, REACH and other environmental regulations, suitable for export products.
Stable performance: does not decompose at high temperature, suitable for long-term high temperature environment.
Low cost: wide source of raw materials, relatively low price, with economic.
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Fifth, development trend
Nanometer: Through nanotechnology to improve the dispersion and efficiency of flame retardants, reduce the amount of addition.
Combination technology: a variety of flame retardants synergistic use, improve the flame retardant effect, reduce costs.
Surface modification: improve the compatibility of flame retardants and substrates, and improve the mechanical properties of materials.
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Inorganic low-smoke halogen-free flame retardants with their environmental protection and high efficiency characteristics are gradually becoming the research and application hotspot in the field of flame retardant materials, and will play an important role in more fields in the future.
