| 摘要 |
PROBLEM TO BE SOLVED: To produce a foam having high durability by foaming an inorganic foaming raw material and starting the hardening immediately after the end of foaming of the inorganic foam. SOLUTION: A thermosetting composition is prepared by adding and mixing 100 pts.wt. of SiO2 -Al2 O3 reactive inorganic powder composed of 5-85 wt.% SiO2 such as fly ash and 90-10 wt.% Al2 O3 , 0.2-450 pts.wt. of an alkali metal silicate expressed by the formula M2 O.nSiO2 [M is K, Na or Li; (n)=0.05-8], 35-1500 pts.wt. of water and 0.01-2 pts.wt. of a foaming agent consisting of peroxide or metal powder having particle diameters of <=200μm. Further, when needed, <=10 pts.wt. of a foaming auxiliary such as calcium stearate, <=700 pts.wt. of an inorganic filler such as silica sand and <=10 wt.% of a reinforcing fiber are compounded. A paste of a foaming material of the composition is cast into a mold, vibration is applied to degas, and then heat is applied to start foaming. The curing reaction is started immediately after a specific time has passed and foaming is completed, and thereby an inorganic foam having closed-cell is formed.
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