| 摘要 |
The invention relates to a process for preparing silicone liquids having water repellant properties, which are used in the construction field for limiting the intrusion of water in vertical or heavily pitched surfaces, such as: facades, vertical masonry, walls, pillars, said process consisting in treating the product resulting from the distillation of dimethyldiclorosilane, containing 20...24% Si, 43...47% Cl, 5...10% dimethyldichlorosilane and 90...95% chlorinated siloxane oligomers, with methyl alcohol containing 0.05% water at most or with anhydrous ethyl alcohol, at a temperature of 10...30°C, in a chlorine/alcohol mass ratio of 1/1.1, the hydrogen chloride being removed by means of a dry nitrogen flow, at a temperature of 10...30°C, the resulting poly-alcoxysiloxane mixture containing 26...31% silicon being subjected to dilution with medium-volatile aromatic or alphatic hydrocarbons down to a concentration of 5...20% silicone substance, finally being passed over solid sodium carbonate. A lower NOx content is ensured as the silicone liquids can be applied on surfaces even in closed spaces, the films limiting the intrusion of water. The costs are reduced and the service life of the buildings is increased by applying the silicone liquids.
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