Glade Squires, OMYA (distributor for Italmatch), presented new PIN FRs based on mineral phosphites (magnesium, calcium, aluminium). These products offer a high phosphorus content and combine two flame retardant mechanisms: water release and polyphosphoric acid which contributes to intumescence and char formation.
Effectiveness is improved by combining forms of phosphorus at different valent states. UL94-V0 was achieved in a number of tested polymers (polypropylene, polyethylene HDPE – LDPE – LLDPE, EVA) at loadings of 22-32%. Blooming (migration) was not detectable after 42 days and corrosion of processing equipment was considerably lower than a reference halogenated FR system.