- Flame Retardants
The most important flame retardants, which are also used as fillers, are aluminum trihydrate (ATH) and magnesium hydroxide (MDH). In addition, antimony trioxide (ATO) is used in large quantities as a synergist with halogenated flame retardants and PVC. Aluminum oxide hydrate (AlOOH or Boehmite) also acts as a synergist in conjunction with metal phosphinates.
Aluminum hydroxide or aluminum trihydrate (ATH) already decomposes at around 200 °C.
Therefore, it only can be used with plastics processed at lower temperatures such as PVC, polyethylene, ethylene/vinyl acetate-copolymers and thermosets.
Aluminum oxide hydrate (AlooH) or Boehmite decomposes at 320 °C. It can therefore be used in engineering thermoplastics and is synergistic with metal phosphinates. It iss also used in printed circuit boards.
Magnesium hydroxide (MDH) decomposes at around 300 °C.
Its main applications are polypropylene, polyamides and wire & cable.
Zinc borate may partly substitute antimony trioxide in thermoplastics, inhibits afterglow and acts as a smoke suppressant. 4ZnO . B2O3 .H2O, which decomposes at 415 °C, is suitable for engineering plastics.
Zinc hydroxystannate is used as a smoke suppressant for PVC, unsaturated polyesters and elastomers.