Flexible polyurethane foam having a high fire resistance

Abstract

A flexible highly elastical polyurethane foam having a density ranging between 25 and 150 kg/m.sup.3 and a relatively high fire resistance obtained by the reaction of an isocyanate and/or a chemically modified derivate thereof with a highly molecular reactive polyol in presence of a catalytic agent, of a cross-linker, and/or an extender, of water as blast means and of a fire retardant, characterized in that said fire retardant comprises at least one of the following components: (1) linear urea-formol oligomer mixture having the general formula NH.sub.2 --CO--NH--[CH.sub.2 --NH--CO--NH].sub.n --CH.sub.2 --NH--CO--NH.sub.2, wherein n can have the value from 0 to 50; (2) urea in powdered form of which the particles are at least partially recovered by a less soluble film, as well as sulfur as of a resin; (3) dicyandiamide having the general formula: ##STR1##

Dependencies are inferred from the claim text.