The primary significance of coating ammonium polyphosphate (APP) with melamine resin

The primary significance of coating ammonium polyphosphate (APP) with melamine resin includes the following aspects:

1. Enhanced Water Resistance – The melamine resin coating forms a hydrophobic barrier, reducing APP’s solubility in water and improving its stability in humid environments.
2. Improved Compatibility with Polymer Matrices – The coated APP disperses more uniformly in various polymers (e.g., polyolefins, epoxy resins), enhancing the overall performance of flame-retardant composites.
3. Increased Thermal Stability – The resin layer delays the decomposition of APP at high temperatures, ensuring more effective flame retardancy during combustion.
4. Reduced Migration and Leaching – The encapsulation minimizes the tendency of APP to migrate or leach out from the polymer matrix, prolonging the flame-retardant effect.
5. Synergistic Flame Retardancy – Melamine resin itself acts as a char-forming agent, working synergistically with APP to enhance intumescent flame retardancy and promote the formation of a stable, insulating char layer.
6. Better Processing Performance – Coated APP exhibits reduced acidity, preventing corrosion of processing equipment and improving handling during manufacturing.

Overall, melamine resin-coated APP offers superior durability, efficiency, and compatibility in flame-retardant applications, making it widely used in plastics, coatings, and textiles.