Abstract: A process for the production of composite bodies of polyurethane foams and covering layers, which includes at least partly lining a mold with a covering layer, and filling the mold with a reaction mixture which reacts to form a polyurethane foam. The reaction mixture which forms a polyurethane foam consists of a polyisocyanate component, a component consisting of at least one organic compound having at least two isocyanate reactive groups, blowing agents, and salts with water of crystallization as additives for improving the bond between the foam and the covering layer.

Abstract: The present invention relates to reactive systems comprising(a) a storable mixture of (i) a polyisocyanate component comprising at least one organic polyisocyanate, and (ii) an epoxide component stabilized by heating in the presence of an alkylating agent, wherein said heating is optionally carried out in the further presence of part of the polyisocyanate component (i),(b) an isocyanate-reactive component containing at least two isocyanate-reactive groups in a quantity such that 0.1 to 0.9 isocyanate-reactive groups are present for every isocyanate group in component (a), wherein at least 10% by weight of component (b) comprises compounds having a molecular weight greater than about 2000,(c) optionally, tertiary amines in a quantity such that the total storable mixture contains at least 0.005 mole of tertiary amine nitrogen atoms for each 100 g of the total amount of the storable mixture, and, optionally,(d) other auxiliaries and additives.

Abstract: The present invention is directed to a process for the preparation of molded polyurethane articles having densities of about 0.8 to 1.4 g/cm.sup.3 and a flex moduli according to DIN 53,457 of at least about 1800 N/mm.sup.

Abstract: The present invention is directed to a process for the production of a molded article having a compact surface layer and a gross density above 900 kg/m.sup.3 via the reaction injection molding technique, comprising introducing a reaction mixture into a closed mold, said reaction mixture comprising:(a) a polyisocyanate component consisting of at least one polyisocyanate in which all the isocyanate groups are aromatically bound,(b) compounds having molecular weights of from 400 to 12,000 and having at least two isocyanate reactive hydrogen atoms,(c) water, in a quantity of at least 0.

Abstract: This invention relates to a process for the production of polyurethane foams in closed molds using mixtures of organic polyisocyanates with certain compounds which liberate carbon dioxide under the catalytic influence of basic compounds. In this process a mixture of polyisocyanates and compounds which liberate carbon dioxide under the catalytic influence of basic compounds is reacted with organic compounds containing hydrogen atoms which are reactive with isocyanate groups, which organic compounds are mixed with basic compounds and/or have basic compounds chemically built into them. The process is suitable for the production of any polyurethane foams in a closed mold, but is preferably applied to the production of semi-hard and particularly of hard polyurethane foams having a dense outer skin.