The applications of guanidine carbonate, guanidine phosphate, and amino sulfonamide guanidine in flame retardancy are as follows:

The flame-retardant mechanism of nitrogen-based flame retardants and common nitrogen-based flame retardants is as follows:

It is generally believed that nitrogen-based flame retardants, when heated, undergo thermal decomposition, releasing non-combustible gases such as ammonia, nitrogen, deep nitrogen oxides, and water vapor. The generation of these gases and the endothermic decomposition of the flame retardant absorb a significant amount of heat, greatly reducing the surface temperature of the polymer.

Moreover, these non-combustible gases, such as nitrogen, not only serve to dilute the oxygen in the air and reduce the concentration of flammable gases produced by the thermal decomposition of high polymers but also react with oxygen in the air to generate nitrogen, water, and deep oxides. This not only consumes oxygen on the material surface but also achieves a good flame-retardant effect.

Currently common nitrogen-based flame retardants include three main categories: melamine, dicyandiamide, guanidine salts (guanidine carbonate, guanidine phosphate, condensed guanidine phosphate, and amino sulfonamide guanidine), and their derivatives, especially phosphate derivatives.

1.Melamine:

Melamine is commonly used as a foaming component in the production of expandable fire-resistant coatings. In addition to being used as a standalone flame retardant, it is often used in combination with acids to produce derived salts. These are widely used in the fields of thermoplastic and thermosetting plastics such as PE, PP, and PVC.

2.Dicyandiamide:

Dicyandiamide is mainly used in the production of guanidine salt flame retardants, either as a replacement for melamine or in combination with melamine. A mixture of dicyandiamide and melamine in specific proportions, added at 5%, can achieve a flame-retardant effect of UL94 V-0 for polyamide. This flame retardant has minimal impact on the tear strength of materials and is also used in the manufacture of fire-resistant adhesives for wood.

3.Guanidine salts (Guanidine carbonate, Guanidine phosphate, Amino sulfonamide guanidine):

Guanidine salts, besides being used as intermediates in pharmaceuticals and dyes, are commonly used as flame retardants for cellulose-based materials such as wood, paper, and cardboard. These flame retardants have long-lasting flame-retardant properties, lower hygroscopicity compared to inorganic flame retardants, and good decorative performance. Therefore, they are widely used in the production of high-quality decorative wood. Additionally, they can be used as a component in expandable fire-resistant coatings as a foaming agent.