Abstract: The invention relates to a process for producing rigid polyurethane foams by reacting a) polyisocyanates with b) compounds having at least hydrogen atoms which are reactive toward isocyanate groups, in the presence of c) blowing agents, wherein the compounds having at least hydrogen atoms which are reactive toward isocyanate groups comprise bi1) at least one polyether alcohol which has been initiated by means of sucrose and/or sorbitol and has a functionality of greater than 4 and a hydroxyl number in the range from 400 to 550 mg KOH/h, bi2) at least one polyether alcohol which has been initiated by means of TDA and has a hydroxyl number in the range from 120 to 240 mg KOH/g and an aromatics content in the range from 6.

Abstract: The invention relates to a process for production of composite elements composed of at least one outer layer a) and of an rigid isocyanate-based foam b), where between the outer layer a) and the rigid isocyanate-based foam b) an adhesion promoter c) has been applied, and where the outer layer a) is continuously moved and the adhesion promoter c) and the starting material for the rigid isocyanate-based foam b) are applied successively to the outer layer, which comprises applying the adhesion promoter c) by means of a rotating plate which has been installed horizontally or with a deviation of up to 15° from horizontal, preferably parallel to the outer layer.

Abstract: The invention relates to a process for producing rigid polyurethane foams by reacting a) polyisocyanates with b) compounds having at least two hydrogen atoms reactive toward isocyanate groups, in the presence of c) catalysts, and d) blowing agents, where, among the compounds having at least two hydrogen atoms reactive toward isocyanate groups, there is at least one graft polyol present capable of preparation via in-situ polymerization of ethylenically unsaturated monomers in polyether alcohols.