PRODUCTION OF ASPHALT FOAM

摘要

PURPOSE:To obtain the titled foam having uniform quality and an excellent effect of sound absorbing and sound insulation, by forming a sheet from a foam prepared by expanding a mixture of an aqueous asphalt emulsion and a urethane prepolymer and compressing the sheet by heating from its surface. CONSTITUTION:A foam is produced by mixing an aqueous asphalt emulsion with a urethane prepolymer obtained by reacting a polyether-polyol of an ethylene oxide content >=15wt% with an organic isocyanate and expanding the formed mixture. This foam is cut into a sheet of a desired thickness. This sheet foam is partially compressed by heating from one or both of its surfaces in the direction of its thickness. Thus, an asphalt foam sheet in which only the superficial part has a high density and the inside part retains a low density can be produced. As a result, a sound absorbing effect by the low-density cellular part and a sound- insulating effect by the high-density layer are imparted to the sheet.