Process for producing rigid polyurethane foams

摘要

The invention relates to a process for producing polyurethanes by reacting
a) polyisocyanates withb) compounds having at least two hydrogen atoms which are reactive toward isocyanate groups,

wherein the compounds b) having at least two hydrogen atoms which are reactive toward isocyanate groups comprise at least one polyether alcohol b1) which has been prepared by reaction of an aromatic amine b1a) with propylene oxide using an amine b1b) which is different from b1a) as catalyst.

主权项

1. A process for producing a polyurethane, the process comprising:
reacting an aromatic amine b1a) with propylene oxide and from 0 to 10% by weight of ethylene oxide relative to a total of propylene and ethylene oxide to obtain at least one polyether alcohol b1) having at least two hydrogens reactive to isocyanate, wherein the reaction of the aromatic amine with propylene oxide and optional ethylene oxide is catalyzed with dimethylethanolamine or imidazole, an amount of the catalyst amine is from 0.1 to 2.5% by mass based on the weight of all starting components, the aromatic amine b1a) is selected from the group consisting of aniline, toluenediamine (TDA), methylenedianiline (MDA) and polymethylenedianiline (PMDA), then reacting compounds b having at least two hydrogen atoms which are reactive toward isocyanate groups, with polyisocyanates a) to yield the polyurethane; wherein the compounds b) having at least two hydrogen atoms which are reactive toward isocyanate groups comprise the at least one polyether alcohol b1).