FIELD: polymer production. SUBSTANCE: invention provides method for preparing molded polyurethane foam involving reaction in closed mold of foam-forming reactive mixture, which contains (i) isocyanate component, major part of which consists of prepolymer with terminal isocyanate groups constituting 5 to 35% based on the total weight of prepolymer prepared by reaction of stoichiometric excess of one or more di- or polyisocyanates with polyol component including polyoxyalkylene- polyether-polyol part and having unsaturation level below 0.03 mequ/g and number-average equivalent weight ca. 1500 to 5000 Da, and (ii) one or more reactive isocyanate components with isocyanate index 70 to 130, optionally in presence of effective amount of catalysts promoting reaction of (i) and (ii), effective amounts of one or more surfactants, and foaming agent ensuring foam density between 0.016 and 0.064 g/cu. cm. EFFECT: improved physical density of polymer foam. 24 cl, 3 tbl, 4 ex
