Preparation of polyurethane foams modified with melamine-formaldehyde precondensates

摘要

A process for the preparation of polyurethane foams modified with melamine-formaldehyde precondensates, in which the precondensates employed are storage-stable, aqueous 40-85% strength by weight resin solutions which are obtained by condensing melamine with formaldehyde in a molar ratio of 1:1.1-1.75 in aqueous solution at a pH which, at least periodically, is above 8, and at from 60 to 130 DEG C., until one part by volume of resin solution can be diluted with from 0.5 to 4 parts by volume of water at 20 DEG C. without causing a persisting cloudiness.