Process for the preparation of carbodiimide-isocyanurate foams

A process for the preparation of a foam characterized by carbodiimide and isocyanurate linkages which comprises condensing an organic polyisocyanate in the presence of a catalyst system comprising based on 100 parts by weight of organic polyisocyanate

• a. from 0.1 part to 10 parts by weight of an s-triazine compound selected from the group consisting of 2,4,6-tris(diethanolamino)-s-triazine, 2,4,6-tris(diisopropanolamino)-s-triazine, 2,4,6-tris(dibutanolamino)-s-triazine, 2,4,6-tris(N-methylethanolamino)-s-triazine, and unsymmetrically substituted triazines of the formula:
• ##SPC2##
• wherein R is hydrogen or lower alkyl of from 1 to 10 carbon atoms, R.sup.1 is CR.sub.2 CR.sub.2 OH or lower alkyl of from 1 to 12 carbon atoms, X is NR.sub.2, alkoxy of from 1 to 12 carbon atoms, phenoxy, alkyl of from 1 to 12 carbon atoms, phenyl, hydroxyl, halogen, aziridyl, pyrrolidyl, piperidyl, or N-alkylpiperazyl,
• b. from 1 part to 6 parts by weight of a 1,3,5-tris(N,N-dialkylaminoalkyl)-s-hexahydrotriazine or the alkylene oxide and water adducts thereof, and
• c. from 0.01 part to 5 parts by weight of a phenolic compound selected from the group consisting of phenol, methylphenols and halophenols.