Abstract: Ammonium sulfate powder is employed, alone, or in conjunction with a weakly basic powder to neuturalize the acidity of the sulfate, as a flame retardant for isocyanate-based foams and, in particular, rigid and flexible polyurethane foams.

Abstract: A blend of liquid hydrocarbon and halogenated aliphatic hydrocarbon is used as a blowing agent. The blowing agent is particularly useful to replace chlorofluorocarbons as blowing agents in isocyanate-based foams.

Abstract: A highly flame retardant and substantially non-combustible polyisocyanurate foam having low friability and no bursting characteristics and method for preparing the same. The method includes the step of reacting an isocyanate having an average isocyanate equivalent weight between about 135 and 145 with a polyether polyol having a hydroxyl number between about 300 and about 600 and a hydroxyl functionality of at least 3. The compounds are combined in amounts to provide NCO/OH equivalent ratio between about 10 and about 50 and are reacted in the presence of a chlorofluorocarbon blowing agent and a catalyst having the general formula: ##STR1## wherein R is a hydrocarbon having between about 1 and about 2 carbon atoms, R' is an alcohol radical having between about 2 and about 3 carbon atoms, and R" is selected from the group consisting of hydrogen and an alkane group having between 1 and 8 carbon atoms.