Polyurethane foam preparation comprises reacting isocyanates with isocyanate reactive compounds in the presence of substituted imidazole catalyst(s)

Polyurethane foam preparation comprises reacting isocyanates with isocyanate reactive compounds in the presence of substituted imidazole catalyst(s) Preparation of polyurethane (PU) foams comprises reacting: (a) isocyanates; (b) isocyanate reactive compounds of mol. wt. 500-8500; and optionally (c) chain extenders and/or crosslinkers of mol. wt. 60-499; in the presence of (d) propellants; and (e) imidazole catalysts of formula (I); and optionally (f) aids and/or additives; R = 1-20C alkyl; R , R = phenyl, halogen, H, 1-4C alkoxy, N-mono or N,N-dialkylamino where the alkyl has 1-4C, , N-mono or N,N-dialkylaminoalkylene where the alkyl has 1-4C and the alkylene has 2-4C; X = 1-6C hydrocarbon or phenyl; A = H, OH or NRZ; Y = H, 2-4C hydroxyalkyl or 2-20C hydroxypolyalkyl; and Z = H, -4C alkyl, phenyl, 2-4C hydroxyalkyl or 2-20C hydroxypolyalkyl. Independent claims are included for the preparation of PU foams as above by reacting 2,4- and/or 2,6-toluylene diisocyanate and/or 4,4'-, 2,2'- and/or 2,4'-diphenylmethane diisocyanate in the presence of 0.02-0.08 wt.% triethylene diamine and 0.05-0.3 wt.% of at least one aminoalkyl and/or an aminophenyl imidazole of formulae (I) or (II) as catalyst and also the use of triethylene diamine and of at least one aminoalkyl and/or an aminophenyl imidazole in a wt. ratio of 1.6-0.06:1 in the preparation of PU foams. R4 = R except halogen and alkoxy; X = 2-6C hydrocarbon or phenyl; A = OH or NYZ. Die Erfindung betrifft ein Verfahren zur Herstellung von Schaumstoffen auf Basis von Polyurethanen durch Umsetzung von (a) Isocyanaten mit (b) gegenüber Isocyanaten reaktiven Verbindungen mit einem Molekulargewicht von 500 bis 8500 und gegebenenfalls (c) Kettenverlängerungs- und/oder Vernetzungsmitteln mit einem Molekulargewicht von 60 bis 499 in Gegenwart von (d) Treibmitteln und (e) Katalysatoren sowie gegebenenfalls (f) Hilfs- und/oder Zusatzstoffen, wobei man als Katalysatoren (e) Imidazole der folgenden Struktur einsetzt: DOLLAR F1