Flame retardant additives are a very important business sector, with annual world sales estimated at over 1.5m. tonnes and a value of about €2bn. The importance of some minerals as flame retardants - such as aluminium hydroxide - is well known and has been discussed in some recent
IM articles (
see IM August 2007). What is not so well recognised is that nearly all of the main commercial products are derived, at least in part, from mineral resources, a link which is discussed in this article.
Two types of flame retardant (FR) additive can be recognised (primary and secondary) and both types are included in the discussion.
Primary FR additives are those that are capable of significantly reducing the flammability of polymers in their own right. The main commercial products of this type are:
Metal hydroxides and related products, principally aluminium hydroxide;
Phosphorus and organic and inorganic phosphates;
Halogen...