Halogen-free flame retardants are flame retardants that do not produce toxic gases (such as hydrogen halide, etc.) when burned. They are composite formula systems with metal oxides as the main components, and add a variety of inorganic substances and organic compounds. Halogen-free flame retardants are widely used in many fields because of their characteristics of non-ignition, non-explosion, less smoke, less toxicity and excellent flame retardancy. The following is an overview of halogen-free flame retardants and their applications:
First, the types of halogen-free flame retardants
Phosphorus based flame retardants
Inorganic phosphorus flame retardants: such as red phosphorus, ammonium polyphosphate, etc. They decompose into phosphoric acid, metaphosphate and other substances during combustion, promote the formation of carbon layer, and generate free radical catcher to terminate the combustion chain reaction.
Organophosphorus flame retardants: such as phosphate esters, phosphonate esters, phosphorus heterocyclic compounds. This kind of flame retardant has the characteristics of low smoke, non-toxic and high efficiency, and is an important direction of flame retardant research in recent years.
Intumescent flame retardant
Mainly with nitrogen and phosphorus as the main components, heat expansion to form a porous carbon layer, so as to block heat and oxygen, to achieve the purpose of flame retardant. This type of flame retardant has the advantages of low smoke, non-toxic, non-corrosive gas generation.
Silicon-based flame retardant
Including silicone flame retardants, polysilboroxane flame retardants and so on. Silicon-based flame retardants can form an insulating layer during combustion, preventing heat exchange and contact with combustible gases, while promoting the generation of carbon and improving the flame retardancy of the material.
Inorganic metal flame retardants
Such as magnesium hydroxide, aluminum hydroxide and so on. This type of flame retardant can absorb a lot of heat during the combustion process, reduce the temperature around the burning object, and produce water vapor, which plays the role of flame retardant and smoke reduction.
Nitrogen based flame retardants
Such as melamine, melamine cyanuric acid and so on. Nitrogen flame retardants can release nitrogen and other inert gases in the combustion process, diluting the oxygen concentration in the combustion area, thus inhibiting the combustion.
Bio-based flame retardants
It is prepared by introducing different phosphorus groups on the main chain of vegetable oil, which has the advantages of biodegradability and non-toxic, and is an important direction of future flame retardant research.
Second, the application of halogen-free flame retardants
Electronic and electrical appliance field
Halogen-free flame retardants are widely used in the flame retardant treatment of wire and cable, circuit board, motor and other components in electronic and electrical equipment. They can effectively improve the flame retardant properties of materials and reduce the risk of fire.
Building materials field
Adding halogen-free flame retardants to building materials can improve its fire resistance, reduce smoke and toxic gas emissions during fire, and ensure people’s life safety.
Vehicle field
The interior trim parts, wire and cable parts in vehicles such as automobiles and aircraft are often treated with halogen-free flame retardants to improve their flame retardant performance and reduce fire hazards.
Textile field
Halogen-free flame retardants are also used in textile fields, such as flame retardant clothing, curtains, etc. They can effectively improve the flame retardancy of textiles and reduce the risk of fire.
Other fields
In addition, halogen-free flame retardants are also used in paint coatings, rubber products and other fields to improve their flame retardant performance and safety.
In summary, there are many kinds of halogen-free flame retardants, each with its own unique properties and advantages. They are widely used in electronic appliances, building materials, vehicles, textiles and other fields, and play an important role in improving the flame retardant performance and safety of materials.
