The Amazing Flame Retardant Effect of Melamine: Scientific Mechanisms and Practical Applications

Uncovering the Mechanisms of Flame Retardancy

The unique physical and chemical properties of melamine are the key to its success in the field of flame retardancy. When this insoluble and non-melting powdery substance is dispersed in the prepolymers of thermoplastic and thermosetting resins, its unique sublimation phenomenon becomes the key to flame retardancy. When heated to 350°C, melamine sublimates instead of melting, a temperature much lower than the ignition temperature of most plastics. Therefore, the heat absorbed during the sublimation process is considered an important source of flame retardancy for melamine. In fact, every kilogram of melamine sublimation can absorb up to -963kJ of heat, which means that for a substrate containing 20% melamine, its temperature can drop by 115°C, which is crucial for preventing plastic from igniting.

The combustion heat of melamine's volatiles is only 40%~45% that of plastic, and the degradation product nitrogen gas has a dual effect of heat dissipation and diluting oxygen concentration. The sublimated particles not only capture free radicals in the flame zone, but also further degrade into dicyandiamide at 610°C, which has a more significant heat absorption effect, thus greatly improving the gas phase flame retardancy efficiency of melamine.

Melamine in Flame Retardant Plastics: From Polyurethane to Polyolefin

A Strong Assistant for Flame Retardant Polyurethane

In the field of flame retardant polyurethane, melamine performs particularly well. It not only increases the heat capacity of polyurethane foam, reduces the surface temperature during combustion, but also effectively slows down the generation and combustion rate of combustible gases. In the initial stage of combustion, the reaction of melamine with isocyanate fragments can also suppress the generation of smoke, providing comprehensive flame retardant protection for polyurethane. Experimental data show that the addition of melamine significantly reduces the key parameters such as heat release rate, smoke release rate, and specific extinction area during the combustion process of flexible polyurethane foam, and the residual ash after combustion contains more nitrogen-containing substances, indicating that melamine also plays a role in promoting the generation of rigid substances in the condensed phase.

A New Choice for Polyolefin Flame Retardancy

For flame retardant treatment of materials such as polyolefin, melamine also shows considerable potential. Although a melamine dosage of over 60% is required for ideal flame retardancy when used alone, the combination of sulfur-based benzothiazole and diisopropyl benzene additives can greatly reduce the dosage to around 25, while achieving LOI values between 27% and 29% and UL 94 levels as high as V-2 to V-0, providing a new approach for flame retardant treatment of polyolefin materials.

Conclusion

As a global leader in the melamine industry, China not only has an absolute advantage in production capacity and output, but also constantly explores and expands the application fields of melamine. Its unique flame retardant mechanism not only provides powerful protection for the fire safety of materials such as plastics, but also injects new vitality into the industry's sustainable development. In the future, with the continuous progress of technology and the continuous expansion of the market, we have reason to believe that the Chinese melamine industry will usher in a more brilliant tomorrow.