MCA exhibits excellent flame retardant effects in unreinforced PA6, while also being low-cost, halogen-free, and non-precipitating. For GF+PA6, a compound formulation using ADP, MPP, and synergists is typically employed. The flame retardant effect of MCA on PA6 goes beyond the commonly understood physical processes of droplet formation or sublimation endothermic reaction; a more significant flame retardant mechanism exists. This mechanism is primarily manifested in the following aspects:

1. MCA Flame Retardant Sublimation Endothermic Reaction: 

During the decomposition of MCA, a significant amount of heat is absorbed, reducing the heat of the polymer material, lowering the surface temperature of the PA6 material, and isolating it from air to achieve flame retardancy. MCA flame-retardant nylon PA6/Nylon PA66 exhibits a sharp, strong endothermic peak around 350℃, indicating a rapid, endothermic decomposition chemical process occurring at this temperature.

2. Expanded Charcoal Layer Flame Retardancy: 

The flame-retardant mechanism of MCA on PA6 goes beyond the physical effects of sublimation endothermy and accelerated dripping. More importantly, it alters the thermo-oxidative degradation process of PA6, causing it to rapidly char into non-combustible charcoal. This charcoal expands and foams, forming a barrier layer on the nylon substrate surface, preventing PA6 from contacting air and escaping combustibles, thus effectively inhibiting continued combustion. Simultaneously, the non-combustible gases produced during decomposition cause the expanded layer to significantly reduce thermal conductivity, promoting self-extinguishing upon removal of the flame.

3. Melting Point Heat Loss: 

When MCA flame-retards PA6, it accelerates PA6 melting and dripping, carrying away heat and combustibles. Even without melting and dripping, MCA maintains excellent flame-retardant properties for PA6.

MCA flame retardant exerts its flame-retardant effect on PA6/66 through three aspects: heat removal by molten droplets, heat absorption by sublimation, and carbon layer barrier. The flame-retardant effect will be even better if it is compounded with other flame retardants.