| 摘要 |
<p>Window surfaces are rendered water and rain repellent by applying a polysilicane in admixture with carbon black and an abrasive cleaning agent having a particle size larger than that of the carbon black. The cleaning agent may be e.g. rouge, cerium oxide, very fine silica or diatomaceous earth, or the fluorides of calcium, barium, strontium and lithium, and may constitute from one-twentieth to ten times the weight of the carbon black. The polysilicanes used are those consisting only of carbon, silicon and hydrogen, and having not less than one Si-Si linkage and one or more aryl or alkyl radicals attached to one of the linked silicon atoms, e.g. tetraethyldiamyldisilicane, diethyltetraamyldisilicane and octaamyltrisilicane. The composition, which is applied by rubbing, may include a hydrocarbon solvent. A coating of wax may subsequently be applied. Specification 648,428 is referred to</p> |
