Abstract: A process for the preparation of a hard foam containing urethane groups or containing urethane and isocyanurate groups involves reactinga) an organic and/or modified organic polyisocyanate withb) at least one high-molecular-weight compound containing at least two reactive hydrogen atoms and, if desired,c) a low-molecular-weight chain extender and/or cross-linking agent,in the presence ofd) a blowing agent,e) a catalyst and, if desired,f) assistants and/or additives,where the blowing agent (d) used is at least one organic carboxylic acid, preferably an aliphatic monocarboxylic acid, alone or in combination with water and/or a physical blowing agent, and the catalyst (e) used is a polyisocyanurate catalyst, preferably an alkali metal salt or ammonium salt of an organic carboxylic acid or tris(dialkylaminoalkyl)-s-hexahydrotriazine.

Abstract: This invention relates to an urethane group containing polyisocyanurate foam produced from a polyisocyanate and a polyhydroxy compound, wherein the polyhydroxy compound is the reaction mixture of a hydroxyl group containing amine which is at least difunctional and is selected from the group consisting of a secondary amine, a tertiary amine, and a mixture thereof, and a naphthenic acid, or a mixture of said reaction mixture and a conventional polyol, the reaction conditions are a temperature between 0.degree. C. and 150.degree. C. and an amino equivalent to carboxylic equivalent of 0.3:1 to 50:1.