Aluminum Hydroxide (ATH) is the most widely used halogen-free flame retardant filler in the world. It is highly cost-effective and functions as a non-toxic flame retardant, smoke suppressant, and arc tracking inhibitor.

Flame Retardant Mechanism ATH’s mechanism is primarily physical, based on its high water content:

1. Endothermic Decomposition: This is the main mechanism. At its decomposition temperature (~220°C), ATH undergoes a powerful endothermic reaction, releasing 34.6% of its weight as non-flammable water vapor.

2. Cooling (Heat Sink): This large-scale water release dramatically cools the polymer substrate below its ignition temperature.

3. Gas Dilution: The massive volume of water vapor dilutes the concentration of flammable gases and oxygen at the flame front, effectively suffocating the fire.

4. Insulating Char: The remaining (alumina) residue forms a protective, insulating ash layer on the polymer surface.

Key Application Areas

• Wire & Cable: Extensively used in cable insulation and jacketing compounds (e.g., XLPE, PVC, rubber) where high filler loadings are acceptable.

• Thermosets: A standard FR for unsaturated polyester (UP) and epoxy resins in applications like electrical panels, construction, and solid surface materials (e.g., artificial marble).

• TPEs & Rubber: Used in various thermoplastic elastomers and rubber compounds (e.g., EPDM).

• Note: Its use is limited to polymers processed below its ~220°C decomposition temperature.