Preparation of flexible, soft polyurethane foams having viscoelastic, structure-borne soundproofing properties, and polyoxyalkylene-polyol mixtures which can be used for this purpose

摘要

The present invention relates to a process for the preparation of flexible, soft polyurethane foams having viscoelastic, structure-borne soundproofing properties in a temperature range of from -20° C. to + 80° C. by reactingPPa) a polyoxyalkylene-polyol mixture containingPPai) block polyoxypropylene- polyoxyethylene-polyol mixture having a hydroxyl number of from 14 to 65 and containing from 2 to 9% by weight of terminal ethylene oxide units, based on the weight of the polyoxypropylene units, prepared by anionic polymerization, at elevated temperatures, of 1,2-propyleneoxide onto an initiator molecule mixture having a mean functionality of from 2.3 to 2.8, comprising water and glycerol and/or trimethylolpropane, and polymerization of acylene oxide onto the resultant polyoxypropylene adduct, andPPaii) one or more difunctional and/or trifunctional polyoxypropylene-polyoxyethylene-polyol containing from 60 to 85% by weight of oxyethylene units, based on the total weight of polymerized alkylene oxide units, and having a hydroxyl number of from 20 to 80, andPPb) if desired low-molecular-weight chain extenders withPPc) organic and/or modified organic polyisocyanates in the presence ofPP d) catalysts, PPe) blowing agents, preferably water, and, if desired, PPf) auxiliaries and/or additives,PPand to the polyoxyalkylene-polyol mixtures (a) which can be used for this purpose.