Aluminum Hydroxide Manufacturer: The Flame Retardant Mechanism of Aluminum Hydroxide

In the flame retardant market, demand for halogen-based flame retardants—once dominant—continues to decline, replaced by halogen-free, low-toxicity alternatives. Among these, aluminum hydroxide produced by aluminum hydroxide manufacturers represents a typical halogen-based flame retardant.

Currently, aluminum hydroxide flame retardants account for over 80% of global inorganic flame retardant consumption. It serves three primary functions: flame retardancy, smoke suppression, and filler material. It produces no secondary pollution during combustion, exhibits synergistic effects with various substances, and is non-volatile, non-toxic, minimally corrosive, and cost-effective. Widely recognized domestically and internationally as an environmentally friendly flame retardant, it is extensively utilized. The flame-retardant mechanism of aluminum hydroxide is as follows:

(1) Heat Absorption and Cooling Effect

At 300-350°C, it undergoes dehydration and absorbs heat. Due to water's high specific heat capacity, its conversion to steam extracts significant thermal energy from the surroundings, thereby suppressing temperature rise in polymers.

(2) Dilution

The steam generated from aluminum hydroxide's dehydration dilutes the concentration of flammable gases and oxygen, preventing combustion.

(3) Coverage

After dehydration, aluminum hydroxide forms an aluminum oxide protective film on combustible surfaces to block oxygen and prevent further combustion.

(4) Carbonization

Under combustion conditions, the flame retardant generates potent dehydrating substances that cause plastics to carbonize without producing flammable volatiles, thereby preventing flame spread. However, as aluminum hydroxide is an inorganic flame retardant, it exhibits performance differences with polymeric materials. Poor affinity between the two leads to uneven dispersion when directly filled. Larger particle sizes also become stress concentration points in the composite, creating weak points that not only limit the amount of polymer that can be added for flame retardancy but also severely impact the product's mechanical properties.

When aluminum hydroxide is used alone, a loading exceeding 60% is required to achieve effective flame retardancy. Such high concentrations adversely affect plastic processing properties and physical-mechanical performance. Therefore, only surface-treated aluminum hydroxide can deliver superior flame retardancy.