| 摘要 |
The present invention relates to a process for producing rigid polyurethane foams or rigid polyisocyanurate foams by the reaction of at least one polyisocyanate A), polyetherester polyols B) based on aromatic dicarboxylic acids obtainable by esterification of b1) 10 to 70 mol % of a dicarboxylic acid composition comprising b11) 50 to 100 mol %, based on the dicarboxylic acid composition, of one or more aromatic dicarboxylic acids or derivatives thereof, b12) 0 to 50 mol %, based on said dicarboxylic acid composition b1), of one or more aliphatic dicarboxylic acids or derivatives thereof, b2) 2 to 30 mol % of one or more fatty acids and/or fatty acid derivatives, b3) 10 to 70 mol % of one or more aliphatic or cycloaliphatic diols having 2 to 18 carbon atoms or alkoxylates thereof, b4) 2 to 50 mol % of a polyether polyol having a functionality of not less than 2, prepared by alkoxylating a polyol having a functionality of not less than 2 in the presence of an amine as catalyst, optionally further polyester polyols C) other than those of component B), and at least one polyether polyol D), wherein the mass ratio of total components B) and optionally C) to component D) is at least 7. The present invention also relates to the rigid foams thus obtainable and also to their use for producing sandwich elements having rigid or flexible outer layers. The present invention further relates to the underlying polyol components. |
