| 摘要 |
PROBLEM TO BE SOLVED: To provide a frame-retarding agent of wood and an anticorrosive agent of steel consisting of an oversaturated colloidal silica soln. produced by deflocculating a silica gel in water in the presence of at least a gas selected from hydrogen, methane and nitrogen at a specified temp. SOLUTION: An autoclave having 500 ml volume is filled with 250 ml water and 10 g silica gel powder, into which methane gas is supplied and sealed to 1 MPA gage pressure. The autoclave is heated to 300 deg.C and then cooled to room temp. to obtain an oversaturated colloidal silica soln. As for the flame resistance treating agent of wood, the concn. of the soln. is controlled and the resultant solution is then applied on wood or impregnated into wood. As for the anticorrosive agent of steel, the aq. soln. is directly used, or the environment of colloidal silica production is constructed from water, gas and silica gel to obtain the anticorrosive effect.
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