PU foam has a wide range of uses and involves various fields of the national economy. Due to its special structure, that is, the oxygen involvement rate is extremely high, and its flame retardant treatment is particularly important. Then, it is best to modify it from its structure. Generally, an isocyanurate structure can be introduced into the PU chain to improve the carbonization tendency of the system and reduce its flammability. However, the application of this method is limited, and the commonly used flame retardants are additive or reactive.

①Additional flame retardants—generally liquid halogen-containing phosphates and phosphonates. The solid flame retardants are melamine, red phosphorus, zinc borate, chlorinated paraffin, ATH, TBC, etc. No matter what kind of flame retardant is required to have good compatibility with each component in PU, there will be no “core burning” phenomenon.

②Reactive flame retardants—mainly all kinds of liquid and solid phosphorus-containing or halogen-containing polyol flame retardant polyethylene basic knowledge ①Generally speaking, flame retardants suitable for PP can be used in PE processing technology, however, due to the difference in structure, thermal stability and pyrolysis temperature, some aromatic brominated flame retardants (such as decabromodiphenyl ether) have better application effect in PE, especially in LDPE.

It should also be pointed out here that chlorine-based flame retardants such as chlorinated paraffin and disclose (product trade name of Western Petrochemical Company in the United States) will have better application effects on some occasions. For example, the application of decline in the PE insulation layer for cables makes PE have excellent voltage resistance and flame retardant effect. Some literature report that when chlorine-based flame retardants are used in combination with brominated flame-retardants, there will be some synergistic effect, although it is not obvious, the flame-retardant effect is better than that when they are used alone.