In recent years, with the increase in the production of plastic products and the improvement of safety standards,flame retardantGenerally speaking, flame retardant materials can be divided into organic flame retardant materials and inorganic flame retardant materials. Among them, organic flame retardant materials are mainly halogen additives, and inorganic materials not only have a certain flame retardant effect, but also produce hydrogen chloride and prevent smoke. In addition, inorganic flame retardant materials are non-toxic, non-corrosive and inexpensive. The consumption of inorganic flame retardant materials in the United States, Japan and other countries exceeds 60%, however, the consumption of inorganic flame retardant materials in China is less than 10%.
① halogen flame retardant
Halogen flame retardants are not only the largest output, but also the most widely used. The material added with the flame retardant can release hydrogen halide during the combustion process and obtain free radicals, thereby preventing the transmission of the combustion chain, thereby generating free radicals with low activity to slow down the combustion. Halogen flame retardants are generally used in thermoplastic materials and thermosetting materials. They are not only compatible with polymer materials, but also easy to use. Therefore, they are welcomed by the market and are widely used in automobiles, packaging, textiles and other industries.
② Phosphorus-based flame retardant
Inorganic phosphorus flame retardant mainly includes phosphate, red phosphorus, etc. Red phosphorus is widely used. Red phosphorus is a good flame retardant. However, in practical application, red phosphorus flame retardant materials are easy to oxidize and release harmful and toxic gases, and dust generated by combustion is easy to cause explosion. There is a certain risk in resin mixing and molding. Therefore, phosphorus flame retardant materials are subject to certain use restrictions. The improved red phosphorus flame retardant is added with metal hydroxide, which solves the problem of polymer material toxicity to a certain extent.
③ Nitrogen flame retardant
Commonly used varieties include melamine, melamine cyanurate (MCA), etc. Synergistic agents are often added. Nitrogen/phosphorus is the most commonly used synergistic flame retardant system, which is mainly used in PA, PU, PO, PET, PS, PVC and other resins.
Melamine cyanurate is a nitrogen-containing halogen-free environmentally friendly flame retardant, especially suitable for PA6 and PA66 without filler, with powder and granular forms. When the flame retardant polyamide foam with this product burns, the carbon foam layer formed protects the polymer and insulates oxygen.
④ Metal oxide flame retardant
Metal oxide flame retardant is mainly to have the essence of flame retardant inorganic elements in the form of elemental or compound added to the flame retardant substrate, in a physical dispersion state and polymer fully mixed, in the gas phase or condensed phase through chemical or physical changes to play a flame retardant effect.
Aluminum hydroxide is the most popular flame retardant for inorganic hydroxides, mainly used for elastomers, thermosetting resins and thermoplastics with processing temperatures below 200°C. Aluminum hydroxide flame retardant plastic in the flame smoke is a prominent advantage.
Magnesium hydroxide is a kind of inorganic flame retardant with better thermal stability, which is still stable over 300 ℃. It is widely used in many artificial rubber, resin, including engineering plastics and other resins under high temperature processing. It plays the role of flame retardant and smoke elimination in the polymer system. With ATH compound use, complement each other, its flame retardant effect is better than alone.