Fillers
In the area of fillers, aluminium oxides Al₂O₃ as well as aluminium oxide trihydrates Al(OH)₃ (ATH) and AlO(OH) boehmites (AMH) are used.
Thermally Conductive Fillers
Aluminium oxides are used as thermally conductive fillers. A relevant thermal conductivity is the last key property that does not exist in plastics - yet! Electrically insulating plastics filled with aluminium oxide acquire thermal conductivity through heat conduction via phonon vibrations. The decisive influencing factor here is the packing density of the alumina in the plastics. The higher the density, the higher the thermal conductivity of the material.
Mipri can draw on a broad product portfolio here.
Applications
Materials filled with alumina can already be found in the field of thermally conductive pastes, which are used as a heat-transferring medium in gaps. Various potting resins and high performace plastics also contain alumina.
Fillers –
Alumina hydrates
Aluminium oxide hydrates are used in various ways in the field of fillers. On the one hand, as halogen-free flame retardant and smoke suppressant fillers for plastic, rubber and special applications.
On the other hand, however, mostly in combination with other fillers, they are also used in the field of thermally conductive plastics.
Aluminium oxide trihydrate (ATH) and boehmite (AMH) fillers decompose by heat into aluminium oxide and water. They are also characterised by the fact that they are non-toxic and non-corrosive.
Flame retardants
Alumina trihydrate is the most widely used and increasingly important environmentally friendly flame retardant on the market. Thermal decomposition starts at about 200°C, making it suitable for a wide range of plastics and rubber applications. For polymers processed at higher temperatures, boehmite (AMH), is the agent of choice. It is thermally stable up to >300°C and offers excellent mechanical properties, high heat capacity.
