Ethylene polymers have been modified by the addition thereto of mineral fillers and organo silanes for the purpose of providing compositions which have improved resistivity to moisture and consequently improved electrical properties as disclosed in U.S. Pat. No. 3,957,719 granted May 18, 1976. For example, organo silanes such as vinyl tris(2-methoxyethoxy) silane have been added to polyethylene compositions containing clay and the resultant compositions suggested for use as insulation about electrical cables. Such compositions, however, have been found deficient when used as insulation about cables carrying high voltage current, on the order of at least five kilovolts. In such cases, it has been found necessary to subject the compositions to a prolonged heat treatment in order that the resultant insulated cables have an acceptable low power factor.
Compositions have also been formulated based on ethylene polymers, mineral fillers and organo titanates and used as insulation about electrical conductors as disclosed in U.S. Pat. No. 4,020,214 granted Apr. 26, 1977. An ethylene polymer composition containing a mineral filler and an organo titanate has not been found acceptable for use as insulation about electrical conductors carrying high voltage current as such composition impairs the transmission efficiency of the insulated electrical conductor.