laus Rathburger, George H. Luh GmbH, presented applications of expandable graphite as a high-performance PIN FR component in applications including textile fire safety, metal fire protection and fire seals (in cable voids, around doors).
Expandable graphite consists of multiple mono-atomic layers of graphite (graphene), to which an acid and an oxidising agent are added so that if heated (to c. 200°C) the layers of graphene expand apart, increasing volume by 200 – 300 times.
This generates a thick intumescent layer, which can insulate against heat (structural protection) and inhibit burning (flame retardancy), and can also reduce smoke emissions by up to 50%. The use of organic acids (e.g. acetic acid, instead of the more generally used sulphuric acid) can avoid acidity in fire from sulphur release.
Klaus Rathburger, sees a continuing movement by customers towards non-halogenated flame retardants. They are not stepping back from flame retardants, because fire safety continues to be demanded both by regulation and by product manufacturers. However, they are looking for new, alternative solutions, with performance packages of PIN flame retardants and synergists with specific functions for different polymers.