Catalysts which stabilize hydrohalocarbon blowing agent in polyisocyanurate foam formulations during polymerization

A process for preparing polyurethane modified polyisocyanurate foam comprising the step of:

• reacting polyol with polyisocyanate in the presence of a blowing agent which consists essentially of a hydrohalocarbon blowing agent, surfactant, and catalyst for polymerization of said polyol and said polyisocyanate wherein said catalyst is selected from the group consisting of hydroxyalkylammonium carboxylates of the formula ##STR8## where n.gtoreq.2;
• R.sub.1, R.sub.2, R.sub.3, R.sub.4, and R.sub.5 are the same or different and selected from hydrogen or alkyl having 1 to 18 carbon atoms;
• and X.sup.- is R.sub.6 CO.sub.2.sup.- where R.sub.6 is ##STR9## where R.sub.7, R.sub.8, and R.sub.9 are the same or different and selected from hydrogen, bromine, chlorine, alkyl having 1 to 18 carbon atoms, or substituted alkyl or alkoxy having 2 to 18 carbon atoms of the formula
• --(O).sub.a --CH.sub.2 --CR.sub.10 R.sub.11 Cl
• where R.sub.10 and R.sub.11 are the same or different and selected from hydrogen, bromine, chlorine, aryl, or alkyl having 1 to 8 carbons and a is 0 or 1 and substituted triazines of the formula
• C.sub.3 H.sub.6 N.sub.3 --[(R.sub.12 R.sub.13 C).sub.n NR.sub.14 R.sub.15 ].sub.3
• where n.gtoreq.2;
• R.sub.12 and R.sub.13 are the same or different and selected from hydrogen and alkyl having 1 to 18 carbon atoms;
• and R.sub.14 and R.sub.15 are the same or different and selected from alkyl having 1 to 18 carbon atoms, cycloalkyl having 1 to 18 carbon atoms, or aryl having 1 to 18 carbon atoms.