WATER-EXCLUDING FILLING COMPOSITIONS

摘要

This invention relates to hydrophobic mineral oil-based compositions and to the use of such compositions as filling compositions particularly for telecommunication cable splice cases. It has been found that filling composition comprising a fluid mineral oil and a hydrophobic fumed silica has excellent water-exclusion properties. Fumed silica can be rendered hydrophobic by treating its surface, and has excellent properties for use as a hydrophobic filling compound, without having the disadvantages of petrolatumbased compositions generally available. The use of a fumed silica thickener having a hydrophobic surface provides a filling composition having improved water-excluding properties and a very low water content compared to similar compositions containing untreated, hydrophilic fumed silica. Resistance to oil separation can be further improved by the addition of a low molecular weight polymeric thickener which is soluble in the mineral oil: depolymerized butyl rubber is preferred.