Abstract: A method of manufacturing polyurethane foams comprising the steps of mixing a polyol and an organic isocyanate without causing them to substantially react with each other thereby to obtain a nonreacted mixture, mixing the nonreacted mixture with a foaming agent, a catalyst, a foam stabilizer and other necessary additives such as a pigment, a fire retardant and a filler, and injecting the resultant mixture to a mold to cause the resultant mixture to foam and crosslink. The polyol and the organic isocyanate may be preliminarily mixed with a gas such as an inert gas or air. The nonreacted mixture containing the polyol and organic isocyanate may be subjected to aging at a temperature of -10.degree. to 25.degree. C. for 12 to 27 hours.

Abstract: A method of producing polyurethane foam slab by allowing a urethane foam stock solution in a tank to expand in a reduced pressure. The flatness of the top of the polyurethane foam is secured by providing a lifting jig or a plate within the tank, or by rotating the tank. An apparatus for carrying out the method is also provided.

Abstract: A method of manufacturing asphalt foam comprising the steps of preparing polyether polyol containing 15 mole % or more of ethylene oxide, preparing urethane prepolymer by making the polyether polyol react with organic isocyanate, and obtaining asphalt foam by mixing the urethane prepolymer with (i) a silicone oil and (ii) an aqueous emulsion of asphalt to obtain an asphalt foam having a five cell structure and excellent water repellancy.

Abstract: An asphalt foam having open cells wherein asphalt mixed with an alkali metal silicate is fixed to the wall of the open cells. The asphalt foam is useful for a joint filler, a vehicle floor material, etc. A method of producing the asphalt foam, which comprises the steps of impregnating an open cell foam sheet with an aqueous mixture consisting of asphalt emulsion and an aqueous solution of an alkali metal silicate, and drying the impregnated foam sheet.