Mechanism of action of melamine flame retardants

Flame retardants work by interfering with one of the three components that initiate and/or support combustion: heat, fuel, and oxygen. Melamine has excellent flame retardant properties because it can interfere with the combustion process in many different ways at all stages. In the initial stage, melamine can delay ignition by causing a heat sink through endothermic dissociation. In the case of melamine salts, melamine itself undergoes endothermic sublimation at approximately 350 ° C. Another larger radiator effect is generated by the subsequent decomposition of melamine vapor.

Melamine can be considered a 'low-quality fuel', with a combustion heat of only 40% of hydrocarbons. In addition, the nitrogen produced by combustion will act as an inert diluent. Another source of inert diluents is ammonia released during the decomposition or partial self condensation of melamine, which does not sublime.

Melamine can also make a significant contribution to the formation of the carbon layer during the expansion process. The carbon layer acts as a barrier between oxygen and polymer decomposition gases. The multi ring structure formed during the self condensation process of melamine enhances the stability of coke. Combined with the phosphorus enhancer melamine, the stability of carbon can be further improved by forming nitrogen and phosphorus substances. Finally, melamine can serve as a foaming agent for coke, enhancing the thermal insulation function of the coke layer.

Metal hydroxide flame retardants are a commonly used series of halogen-free flame retardants. These mineral compounds are used for polyolefins TPE、PVC、 Rubber, thermosetting plastics, and some engineering polymers (such as polyamide) can also be used.

The flame retardant formula they provide meets appropriate standards for many applications. The combustion products produced by this formula have low opacity, low toxicity, and minimal corrosiveness. When mixed appropriately, inorganic hydroxides provide a cost-effective method for achieving low smoke flame retardant formulations.

In addition, inorganic hydroxides are easy to handle and relatively non-toxic. Aluminum trihydroxide (ATH), magnesium dihydroxide (MDH), and various other inorganic hydroxides are replacing halogenated and phosphorus containing flame retardants due to their long-term impact on the environment.