| 摘要 |
<p>A process for producing rigid polyurethane foams by reacting a) organic polyisocyanates with b) compounds having at least two hydrogen atoms which are reactive toward isocyanate groups in the presence of c) blowing agents, d) catalysts and, if appropriate, e) auxiliaries and additives, wherein a mixture of b1) from 20 to 60 parts by weight of one or more high-functionality polyether alcohols having functionalities of from 3.5 to 5.5 and a hydroxyl number of from 400 to 550 mg KOH/g, b2) from 1 to 20 parts by weight of one or more polyether alcohols based on aliphatic amines and having functionalities of from 3.5 to 4.5 and a hydroxyl number of from 450 to 900 mg KOH/g, b3) from 10 to 30 parts by weight of one or more polyether alcohols and/or aromatic polyester alcohols having functionalities of from 1.5 to 3 and a hydroxyl number of from 150 to 450 mg KOH/g, and b4) optionally from 1 to 5 parts by weight of water is used as polyol component b). The polyol component b) of the invention has good storage stability and the rigid polyurethane foams obtained have a good surface quality, curing and adhesion.</p> |
