Novel four components self-layering fire retardant systems designed on steel
Epoxy/Silicone self-stratifying coatings
Evidences of layering behavior were exhbited on steel, with a concentration grafdient of silicone from the subtrate to the interface with the air. The system was also tested in combination with various fire retardant fillers dispersed in the epoxy phase (iron oxide, calcium carbonate or a phosphorus based additive), however the results were not as conclusive as they were when the system was applied on PC. With calcium carbonate, phase separation occurred and evidences of orientation of the phases were noted. Moreover, calcium carbonate was found in the epoxy phase whereas it migrated to the silicone layer when applied on PC.
Epoxy/Fluoropolymer self-stratifying coatings
Epoxy/fluoropolymer system diluted in BuAc: xylene (1:1) applied on steel also gave conclusive results: a perfect stratification was obtained with the unfilled system and also when iron oxide was incorporated in the epoxy phase. The fluoropolymer migrated to the upper layer of the film and the epoxy layer to the substrate.