METHOD OF MANUFACTURING POROUS ACOUSTIC MATERIAL

摘要

PROBLEM TO BE SOLVED: To provide a method of manufacturing a porous acoustic material which does not require the prolonging of the hardening time of a slurry in order to suppress the development of the crack, has high strength and high durability. SOLUTION: The method of manufacturing the porous acoustic material consists in allowing many air bubbles to exist in an aqueous raw material slurry prepared by using siliceous raw material containing cement and calcareous raw material as main raw materials and compounding a polyoxyethylene alkyl ether sulfate as a surfactant and a thickener therewith and half hardening the raw material slurry by hydration reaction at the maximum curing temperature regulated to 75 to 95 deg.C in the state that bubble films are formed between the air bubbles by the contact of the plural adjacent air bubbles with each other by the effect of the surfactant and the thickener and subjecting the half hardened material to normal hardening by autoclave curing to annihilate the bubble films between the air bubbles and in which the total volume of the open cells occupies >=30% of the entire volume.