COMPOSITION FOR PREPARING FOAM PLASTIC Russian patent published in 1997 - IPC

FIELD: manufacture of building materials. SUBSTANCE: foaming composition comprises the following components, wt.-%: polyethylene, 60-70; azodicarbonamide, 3-5; vulcanic rock selected from pumice, perlite, vulcanic slag or their mixtures, 0.1-36.9; and the same rock previously treated with aqueous sodium hydroxide solution with concentration 40-80 g/l at temperature of 80-100 C at S to L ratio of 1:(2.7-5) for 1 or 2 h followed by drying of residue after decantation of liquid phase, 0.1-24.9. EFFECT: improved strength characteristics and heat resistance. 5 tbl