PIN FR solutions with phosphorus, nitrogen organo-clay and nano-silica enables UL94-V0 in epoxy at 30% loading.
The authors tested a PIN combination of organically modified sodium montmorillonite (OMMT), amino-functionalised nano silica (nano-silica) and intumescent PIN FR (IFR: ammonium polyphosphate, melamine and pentaerythritol) in epoxy resin. In all cases, total PIN FR loading was 30% w/w. Optimal LOI (28% compared to 19% for neat epoxy), as well as IL94-V0 (4 mm) was achieved with a combination of all three PIN FR components: 27% IFR, 1.5% OMMT, 1.5% nano-silica. The authors conclude that well dispersed OMMT and nano-silica act in synergy to improve the performance of standard PIN intumescent flame retardant in epoxy, by facilitating formation of more compact and continuous char.
“Combination effect of organically modified montmorillonite and nano-silica on reducing the fire hazards of intumescent flame-retarded epoxy resins”, L. Yan et al., J Vinyl Addit Technol. 2020;26:490–501, https://dx.doi.org/10.1002/vnl.21764