A new group of liquid reactive nitrogen and nitrogen-phosphorus flame retardants for self-extinguishing polyurethane expanded polymers. Part. II. Applications to flexible polyurethane foams

A method is described to produce self-extinguishing flexible polyurethane foams (PTPUR) containing new liquid reactive nitrogen-phosphorus flame retardants based on melamine. Selected property data of the foams are given. Since the nitrogen flame retardants produce an autocatalytic effect, PTPUR can be prepared with only minor amounts of a catalyst or none. Thus the toxic and volatile amine catalysts can be eliminated. Sodium lauryl sulfate (Table 1) proved to be the best surfactant to prepare PTPUR containing the new nitrogen and nitrogen-phosphorus flame retardants (Table 1). The density of PTPUR was 32-70 kg/m(3). The oxygen index of the resulting PTPUR rose from 19.5 to 23.1% (no bromine compounds) (Tables 2, 3) and to 24.9% (with bromine compounds added) (Table 5) and the flammability of the PTPUR measured in terms of the length of burnt sample fell from 150 to 28 mm (Table 5). Organotin catalysts are antagonistic to bromine compounds and suppress their effectivity; their amounts should not exceed 1%. In most cases, the PTPUR were harder as the proportion of the flame retardants was increased in the polyol mixture. A drawback to the flame retardants is the PTPUR plastics strain that rises as the proportion of the flame retardants is increased (Tables 2-5).