RIGID, DIMENSIONALLY STABLE POLYURETHANE FOAMS AND A PROCESS FOR THE PRODUCTION OF SUCH FOAMS IN WHICH THE FOAM PRESSURE IS REDUCED

Rigid foams are made by reacting a polyisocyanate with an isocyanate-reactive composition which includes at least one isocyanate-reactive compound, preferably, an amine-initiated polyol and more preferably, an amine-initiated polyether polyol and a second, different polyol in the presence of a blowing agent composition which includes water and a catalyst composition which includes two different blowing catalysts, preferably, pentamethyldiethylenetriamine and bis(2-dimethylamino-ethyl)ether. Las espumas rigidas se preparan haciendo reaccionar un poliisocianato con una composicion reactiva con isocianato que incluye al menos un compuesto reactivo con isocianato, preferiblemente, un poliol iniciado en amina y, mas preferiblemente, un poliol de polieter iniciado en amina y un segundo poliol diferente en presencia de una composicion de un agente de soplado que incluye agua y una composicion de catalizador que incluye dos catalizadores de soplado diferentes, preferiblemente pentametildietilentriamina y bis(2-dimetilaminoetil) eter.