Silicone water block for electrical cables

Claim 1

A method of extending the serviceable life of a stranded conductor electrical distribution cable comprising: (i) filling the interstices of said conductor with a curable water block composition, and (ii) curing said composition to a non-flowing state, said composition comprising (A) an Si-H endblocked polydiorganosiloxane fluid having a viscosity of 0.5 to about 100 centistokes at 25° C. and represented by the formula H(R' 2 SiO) x (R' 2 Si)H wherein R' is independently selected from alkyl radicals having from 1 to 6 carbon atoms or the phenyl radical and the average value of x is 1 to 40; (B) a polydiorganosiloxane fluid having a viscosity of 0.5 to about 100 centistokes at 25° C. and represented by the formula ##STR12## wherein G denotes unsaturated radicals independently selected from the vinyl group or higher alkenyl radicals represented by the formula --R'"(CH 2 ) m CH═CH 2 , in which R'" denotes --(CH 2 )p-- or --(CH 2 ) q CH═CH--, m is 1, 2, or 3, p is 3 or 6 and q is 3, 4 or 5, R" is independently selected from an alkyl radical having 1 to 6 carbon atoms or a phenyl radical and y is on the average from 1 to about 40; (C) a siloxane crosslinker selected from short chain linear or cyclic siloxanes containing SiH functionality or Si-G functionality, in which G has the above-defined meaning; (D) sufficient hydrosilation catalyst to cure the mixture of (A), (B), and (C); and (E) sufficient polymerization inhibitor to prevent the water block composition from curing to a non-flowing state before the cable is filled with the combination of (A), (B), (C), (D) and (E).

Claim 2

A method of extending the serviceable life of a stranded conductor electrical distribution cable comprising: (i) filling the interstices of said conductor with a curable water block composition, and (ii) curing said composition to a non-flowing state, said composition comprising (A) an Si-H endblocked polydiorganosiloxane fluid having a viscosity of 0.5 to about 100 centistokes at 25° C. and represented by the formula H(R' 2 SiO) x (R' 2 Si)H wherein R' is independently selected from alkyl radicals having from 1 to 6 carbon atoms or the phenyl radical and the average value of x is 1 to 40; (B) a polydiorganosiloxane fluid having a viscosity of 0.5 to about 100 centistokes at 25° C. and represented by the formula ##STR12## wherein G denotes unsaturated radicals independently selected from the vinyl group or higher alkenyl radicals represented by the formula --R'"(CH 2 ) m CH═CH 2 , in which R'" denotes --(CH 2 )p-- or --(CH 2 ) q CH═CH--, m is 1, 2, or 3, p is 3 or 6 and q is 3, 4 or 5, R" is independently selected from an alkyl radical having 1 to 6 carbon atoms or a phenyl radical and y is on the average from 1 to about 40; (C) a siloxane crosslinker selected from short chain linear or cyclic siloxanes containing SiH functionality or Si-G functionality, in which G has the above-defined meaning; (D) sufficient hydrosilation catalyst to cure the mixture of (A), (B), and (C); and (E) sufficient polymerization inhibitor to prevent the water block composition from curing to a non-flowing state before the cable is filled with the combination of (A), (B), (C), (D) and (E).