Rigid polyurethane foams with improved flame resistance

The effect of the amount of the modified silicates and commercial flame retardants on the properties of rigid polyurethane foams (SPPUR) was investigated. The foams were prepared in a one-step process from two-component system: polyol premix and isocyanate. The mechanical and physical properties as well as flame resistance of the prepared rigid foams were evaluated. The structure of foams was analyzed using optical microscope. It was found that the polyurethane foam containing ammonium polyphosphate (APP), triethyl phosphate (TEP) and halloysite modified with melamine-formaldehyde resin (HALM) had the lowest flammability (class V-1, LOI = 23.5 %) while the reference sample was not classified in the UL94 test (LOI = 19.7 %).