In modern industry, flame retardancy and smoke suppression have become essential safety requirements for plastic and polymer products. As a highly effective, environmentally friendly, and cost-effective inorganic flame retardant filler, aluminum hydroxide is increasingly being used in various polymer systems. It not only offers excellent flame retardancy and smoke suppression, but also excels in color stability, particle size controllability, and operational safety.

1. Flame Retardant Advantages and Working Principles of Aluminum Hydroxide

Aluminum hydroxide's popularity as a flame retardant filler is primarily due to its unique decomposition properties:

Heat-Absorption and Cooling: When temperatures exceed 200°C, aluminum hydroxide decomposes into aluminum oxide and releases water vapor. This process is highly heat-absorbent, effectively lowering the material's surface temperature and slowing down the thermal decomposition of the polymer.

Dilution Gas: The released water vapor dilutes the concentration of combustible gases, suppressing the spread of flames.

Promoting Carbonization: The decomposition residue promotes the formation of a solid carbon layer, further isolating oxygen and heat, improving the material's fire resistance. Aluminum hydroxide also offers numerous advantages, including high whiteness, a well-defined particle size distribution, stable chemical properties, and non-toxicity, making it an environmentally friendly flame retardant.

2. Applications in Various Polymer Systems

Carpet Adhesive and Latex Foam

Aluminum hydroxide was one of the earliest flame-retardant fillers used on a large scale in the carpet industry. Appropriate addition helps products pass rigorous combustion tests (such as the "balling test"). Particle sizes of 15-45 μm are typically used to achieve enhanced flame retardancy while avoiding foam structure collapse.

Unsaturated Polyester and Epoxy Resins

In these thermosetting resins, aluminum hydroxide can significantly increase the oxygen index and reduce smoke generation. Even at high filler loadings (e.g., 40-80%), it maintains excellent electrical properties, making it suitable for electrical insulation. Fine-particle, low-sodium grades offer superior performance.

Other Polymers

Aluminum hydroxide also demonstrates excellent flame retardancy and smoke suppression in polyurethane, PVC, rubber, and glass fiber-reinforced plastics. While it may slightly affect tensile strength, its contribution to improving fire safety far outweighs this limitation.