| 摘要 |
PROBLEM TO BE SOLVED: To easily restore the appearance and the function of a construction material colored and polluted by a dyeing agent by applying a decolorizing solution containing an oxidative alkaline component to polluted points and carrying out partial decolorization for the polluted points. SOLUTION: A decolorizing solution containing an oxidative alkaline component is applied to polluted points to carry out partial decolorization for the polluted points. The decolorization method of the polluted material is carried out by penetrating a soft material such as tissue paper and cloth with a removing solution and either applying the solution to the polluted points or penetrating the points with the solution. Duration of such a process is kept about 3-5 minutes continuously. The decolorization solution employed for the method is an aqueous solution containing at least a hypochlous acid salt. The decolorization solution preferably contains 1-10 wt.% of hypochlorous acid salt and is alkaline with pH 12.5-13. In the case pH is 12.5 or lower, the decolorization capability is lowered and in the case pH is 13 or higher, the solution causes excess irritation on the skin, so that it is not preferable. Further, the decolorization solution may contain NaOH, KOH. Furthermore, the decolorization solution preferably contains a surfactant.
|
