Aluminum trihydrate (also known as aluminum hydrate, alumina hydrate, aluminum hydroxide, or ATH) is a filler, extender pigment, and bodying agent in oil- and water-borne paint that does not greatly affect the color of the paint. This is an 8-micron median particle size extender that is a white to tan colored powder and can be added to paint to impart transparency to the paint film.
Alumina trihydrate (AI2O3•3H2O) is the most widely used flame retardant in commercial coatings due to its versatility and low cost. It can be used in a wide range of paint binders at processing temperatures below 220°C. ATH is non-toxic, halogen-free, chemically inert, and has low abrasiveness. Additional benefits are acid resistance and smoke suppression. At about 220°C, ATH begins to decompose endothermically releasing approximately 35% of its weight as water vapor.
AI2O3•3H2O + HEAT —–> AI2O3 + 3 H2O
Alumina trihydrate acts as a heat sink thereby retarding pyrolysis and reducing the burning rate. The water vapor released has an added effect of diluting combustion gases and toxic fumes.
| Specifications | |
| Physical Properties | |
| Median Particle Size | 8 microns |
| Sieve Residue >45 microns (+325 mesh) | 0.15% |
| Brightness, L | 91 |
| Specific Gravity | 2.42 g/cm3 |
| Oil Absorption | 19 mL/100g |
| Bulk Density, Loose | 50 lbs./ft3 |
| Bulk Density, Packed | 70 lbs./ft3 |
| pH | 8 |
| Chemical Analysis (Typical) | |
| Al(OH)3 | 99.5% |
| Na2O | 0.30% |
| SiO2 | 0.005–0.02% |
| Fe2O3 | 0.009–0.02% |
| Free Moisture | 0.25% |
The information herein is believed to be correct and reliable; however, no warranty is given concerning the accuracy of the data, merchantability, or fitness for a particular use.