Intumescent Polyisocyanurate Polyurethane Foams

EG-triethylphosphate (TEP) [17, 65], APP-melamine ammonium phosphate and APP-PA-6 and cyanurate-EG [66] have all been used in intumescent studies on polyisocyanurate-polyurethane (PU) foams. 

TEP-EG filled PU foams [65] showed an overall improvement of their fire behaviour, the LOI increasing and the RHR decreasing with increasing filler content. The best fire performance was obtained using TEP and EG in a synergistic combination. 

Physical-mechanical and morphological characterisation shows that in these polymers the presence of filler causes only slight worsening of physical and mechanical properties. In particular the greatest effect of flame retardants has been seen on the thermal conductivity for EG filled foams. 

The filled foams show an overall improvement of their fire behavionr the higher the filler content the higher the LOI and the lower the RHR. In particnlar, the best fire performances are obtained using both TEP and EG in synergistic combination. 

The fire reaction of filled polyisocyanurate-PU foams has been analysed by use of DIN 4102-2 [22] and LOI tests. The results of the DIN 4102-2 test are reported in Table 7.1. Only the foams filled with EG containing at least 15 wt% of filler, can be classified as B2 materials. Pentane blown foams filled with 25 % of APP and MC cannot be rated as B2. 

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Modesti, M. Lorenzetti, A. Simioni, F. Camino G. Expandable graphite as an intumescent flame retardant in polyisocyanurate-polyurethane foams. Polym. Degrad. Stab. 2002, 77, 195-202. 

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