The composite material based on resin and rubber contains a large amount of organic compounds and has certain flammability. Flame retardants are a class of additives that prevent the ignition of polymeric materials or inhibit flame transfer. It is common and important that the flame retardant is a compound of phosphorus, bromine, chlorine, ruthenium and aluminum. Flame retardants can be divided into two types according to the use method: additive type and reactive type. Additive flame retardants mainly include phosphate esters, halogenated hydrocarbons and cerium oxide. They are blended into the composite material during the processing of the composite material, which is convenient to use and has a large adaptability surface but has an influence on the performance of the composite material. The reactive flame retardant is added to the polymerization system as a raw material in the preparation process of the polymer, and is chemically reacted to the polymer molecular chain, so that the performance of the composite material is less affected, and the flame retardancy is small. lasting. The reactive flame retardant mainly includes a phosphorus-containing polyol and a halogenated acid anhydride.
The flame retardant used in the composite material should have the following properties: 1 high flame retardant efficiency, can give the composite material good self-extinguishing or flame retardancy; 2 has good mutual compatibility, and can be well compatible with the composite material. And easy to disperse; 3 has a suitable decomposition temperature, that is, does not decompose at the processing temperature of the composite material, but can rapidly decompose when the composite material is thermally decomposed to exert a flame retardant effect; 4 non-toxic or low-toxic, odorless, No pollution, no toxic gas is produced during the flame retardant process; 5 when combined with the composite material, does not reduce the mechanical properties, electrical properties, weather resistance and heat distortion temperature of the composite material; 6 good durability, can remain in the composite material for a long time In the products, play its flame retardant effect; 7 sources are widely available at low prices.
The flame retardants of composite materials mainly have the following categories:
1. Brominated flame retardants Brominated flame retardants include aliphatic, alicyclic, aromatic and aromatic-aliphatic bromine-containing compounds. These flame retardants have high flame retardant efficiency and their flame retardant effect is chlorine resistance. Double of the fuel, relatively small amount, has little effect on the mechanical properties of the composite, and can significantly reduce the content of hydrogen halide in the gas, and the flame retardant and the matrix resin have good compatibility, even if it is harsh There is no spray on the condition.
2. Chlorine-based flame retardant Chlorine-based flame retardant is still a widely used flame retardant due to its low personality. Chlorinated paraffin with high chlorine content is an industrially important flame retardant. Due to poor thermal stability, it is only suitable for composite materials with processing temperature below 200 °C, thermal stability of chlorinated alicyclic hydrocarbons and tetrachlorophthalic anhydride. Higher, often used as a flame retardant for unsaturated resins.
3. Phosphorus-based flame retardants and organic phosphides are additive flame retardants. The metaphosphoric acid produced by the combustion of such flame retardants can form stable multimers, covering the surface of the composite material to isolate oxygen and combustibles, and The flame retarding effect is better than that of bromide. To achieve the same flame retardant effect, the amount of bromide is 4-7 times that of phosphide. These flame retardants are mainly phosphorus (phosphonate) and halogenated phosphates and phosphorus halides, etc., widely used in epoxy resin, phenolic resin, polyester, polycarbonate, polyurethane, polyvinyl chloride, polyethylene, Polypropylene, ABS, etc.
4. Inorganic Flame Retardants Inorganic flame retardants are a class of flame retardants classified according to their chemical structure, including cerium oxide, aluminum hydroxide, magnesium hydroxide and zinc borate.