Claims
- 1. A method for restoring in-service electrical distribution cable having a stranded conductor and polyolefin insulation, comprising:
- (i) drying the interstices of said conductor,
- (ii) exposing the interior of said cable to an anti-treeing additive till said additive is absorbed by the insulation,
- (iii) filling the interstices of said stranded conductor with a water block composition comprising
- (A) an Si-H endblocked polydiorganosiloxane fluid having a viscosity of 0.5 to about 100 centistokes at 25.degree. C. and represented by the formula H(R'.sub.2 SiO).sub.x SiR'.sub.2 H wherein R' is independently selected from the group consisting of alkyl radicals having from 1 to 6 carbon atoms and a 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.degree. C. and represented by the formula ##STR12## wherein G denotes an unsaturated radical independently selected from the group consisting of a vinyl group and higher alkenyl radicals represented by the formula --R'''(CH.sub.2).sub.m CH.dbd.CH.sub.2, in which R''' is selected from the group consisting of --(CH.sub.2).sub.p --and --(CH.sub.2) .sub.q CH.dbd.CH--, m is 1, 2, or 3, p is 3 or 6 and q is 3, 4 or 5, R" is independently selected from the group consisting of an alkyl radical having 1 to 6 carbon atoms and a phenyl radical and y has average value of 1 to about 40;
- (C) a siloxane crosslinker selected from the group consisting of short chain linear siloxanes and cyclic siloxanes, said crosslinker containing functionality selected from the group consisting of Si-H and 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 allow the cable to be filled with the combination of (A), (B), (C), (D) and (E) before said combination cures to a non-flowing state, and
- (iv) curing said water block composition to a non-flowing state.
- 2. The method according to claim 1, wherein said siloxane crosslinker (C) is selected from the group consisting of
- (a) linear species represented by the average formula ##STR13## (b) linear species represented by the average formula ##STR14## and (c) cyclic species represented by the formula ##STR15## wherein R' is independently selected from the group consisting of alkyl radicals having from 1 to 6 carbon atoms and a phenyl radical, Q is selected from the group consisting of hydrogen and an unsaturated radical independently selected from the group consisting of a vinyl group and higher alkenyl radicals represented by the formula --R'''(CH.sub.2).sub.m CH.dbd.CH.sub.2, in which R''' is selected from the group consisting of --(CH.sub.2).sub.p --and --(CH.sub.2).sub.q CH.dbd.CH--, m is 1, 2, or 3, p is 3 or 6 and q is 3, 4 or 5, j is 3 to about 100, k is 1 to about 100 and z is 3 to about 6.
- 3. The method according to claim 2, wherein said group G of said component (B) is selected from the group consisting of vinyl and 5-hesenyl radicals.
- 4. The method according to claim 3, wherein R' of said components (A) and (C), and R" of said component (B) are each a methyl radical.
- 5. The method according to claim 4, wherein G of said component (B) is a vinyl radical and said siloxane crosslinker (C) is (MeViSiO).sub.z, in which Me denotes a methyl radical, Vi denotes a vinyl radical and z is on average 3 to about 6.
- 6. The method according to claim 5, wherein x of said component (A) is about 5 to 20 and y of said component (B) is about 5 to 20.
- 7. The method according to claim 6, wherein about 100 parts by weight of component (A), about 54 parts by weight of component (B) and about 0.5 part by weight of component (C) are employed in said water block composition and wherein x is about 15 and y is about 7.
- 8. The method according to claim 7, wherein said hydrosilation catalyst is a chloroplatinic acid complex of divinyltetramethyldisiloxane diluted in dimethylvinylsiloxy endblocked polydimethylsiloxane and said polymerization inhibitor is bis(2-methoxy-1-methylethyl) maleate.
- 9. The method according to claim 8, wherein said antitreeing additive is phenylmethyldimethoxysilane.
- 10. The method according to claim 4, wherein said antitreeing additive is phenylmethyldimethoxysilane.
- 11. The method according to claim 5, wherein said antitreeing additive is phenylmethyldimethoxysilane.
- 12. The method according to claim 6, wherein said antitreeing additive is phenylmethyldimethoxysilane.
- 13. A method for restoring in-service electrical distribution cable having a stranded conductor and polyolefin insulation, comprising:
- (i) drying the interstices of said conductor,
- (ii) filling the interstices of said stranded conductor with a homogeneous mixture of an anti-treeing additive and a water block composition, said water block composition comprising
- (A) an Si-H endblocked polydiorganosiloxane fluid having a viscosity of 0.5 to about 100 centistokes at 25.degree. C. and represented by the formula H(R'.sub.2 SiO) .sub.x SiR'.sub.2 H wherein R' is independently selected from the group consisting of alkyl radicals having from 1 to 6 carbon atoms and a 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.degree. C. and represented by the formula ##STR16## wherein G denotes an unsaturated radical independently selected from the group consisting of a vinyl group and higher alkenyl radicals represented by the formula --R'''(CH.sub.2).sub.m CH.dbd.CH.sub.2, in which R''' is selected from the group consisting of--(CH.sub.2).sub.p --and--(CH.sub.2).sub.q CH.dbd.CH--, m is 1, 2, or 3, p is 3 or 6 and q is 3, 4 or 5, R" is independently selected from the group consisting of an alkyl radical having 1 to 6 carbon atoms and a phenyl radical and y has average value of 1 to about 40;
- (C) a siloxane crosslinker selected from the group consisting of short chain linear siloxanes and cyclic siloxanes, said crosslinker containing functionality selected from the group consisting of Si-H and 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 allow the cable to be filled with the combination of (A), (B), (C), (D) and (E) before said combination cures to a non-flowing state, and
- (iii) curing said water block composition to a non-flowing state.
- 14. The method according to claim 13, wherein said siloxane crosslinker (C) is selected from the group consisting of
- (a) linear species represented by the average formula ##STR17## (b) linear species represented by the average formula ##STR18## and (c) cyclic species represented by the formula ##STR19## wherein R' is independently selected from the group consisting of alkyl radicals having from 1 to 6 carbon atoms and a phenyl radical, Q is selected from the group consisting of hydrogen and an unsaturated radical independently selected from the group consisting of a vinyl group and higher alkenyl radicals represented by the formula --R'''(CH.sub.2).sub.m CH.dbd.CH.sub.2, in which R''' is selected from the group consisting of --(CH.sub.2).sub.p --and--(CH.sub.2).sub.q CH.dbd.CH--, m is 1, 2, or 3, p is 3 or 6 and q is 3, 4 or 5, j is 3 to about 100, k is 1 to about 100 and z is 3 to about 6.
- 15. The method according to claim 14, wherein said group G of said component (B) is selected from the group consisting of vinyl and 5-hexenyl radicals.
- 16. The method according to claim 15, wherein R' of said components (A) and (C), and R" of said component (B) are each a methyl radical.
- 17. The method according to claim 16, wherein G of said component (B) is a vinyl radical and said siloxane crosslinker (C) is (MeViSiO).sub.z, in which Me denotes a methyl radical, Vi denotes a vinyl radical and z is on average 3 to about 6.
- 18. The method according to claim 17, wherein x of said component (A) is about 5 to 20 and y of said component (B) is about 5 to 20.
- 19. The method according to claim 18, wherein about 100 parts by weight of component (A), about 54 parts by weight of component (B) and about 0.5 part by weight of component (C) are employed in said water block composition and wherein x is about 15 and y is about 7.
- 20. The method according to claim 19, wherein said hydrosilation catalyst is a chloroplatinic acid complex of divinyltetramethyldisiloxane diluted in dimethylvinylsiloxy endblocked polydimethylsiloxane and said polymerization inhibitor is bis(2-methoxy-1-methylethyl) maleate.
- 21. The method according to claim 20, wherein said antitreeing additive is phenylmethyldimethoxysilane.
- 22. The method according to claim 16, wherein said antitreeing additive is phenylmethyldimethoxysilane.
- 23. The method according to claim 17 wherein said antitreeing additive is phenylmethyldimethoxysilane.
- 24. The method according to claim 18, wherein said antitreeing additive is phenylmethyldimethoxysilane.
Parent Case Info
This is a continuation-in-part of copending application Ser. No. 041,558, filed on Apr. 23, 1987, now U.S. Pat. No. 4,845,309, patented July 4, 1989.
US Referenced Citations (11)
Foreign Referenced Citations (3)
Number |
Date |
Country |
1640722 |
Sep 1967 |
DEX |
2729368 |
Jun 1977 |
DEX |
3304715 |
Feb 1983 |
DEX |
Non-Patent Literature Citations (1)
Entry |
Eager. IEEE Transaction on Power Apparatus and Systems, vol. PAS-103, No. 8, Aug., 1984, pp. 1997-2005. |
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
41558 |
Apr 1987 |
|