Silane functional stabilizers for extending long-term electrical power cable performance

Abstract

Provided are methods for extending the life of in-service electrical cable having polymeric insulation, comprising injecting a dielectric enhancement fluid composition into the cable, wherein the composition comprises: (a) one or more organoalkoxysilane functional additives (voltage stabilizer-based, hindered amine light stabilizer (HALS)-based, and/or UV absorber-based); and (b) a catalyst suitable to catalyze hydrolysis and condensation of (a), the injected composition providing for rapid initial permeation of (a) into the insulation, and extended retention of subsequent condensation products of (a) in the insulation. Additionally provided are innovative silyl functional ferrocenes (e.g., containing a ferrocene moiety and a silyl function hydrolysable to silanol) having utility as functional voltage stabilizing additives in the methods.

1 . A method for extending the useful life of in-service electrical cable, comprising injecting a dielectric enhancement fluid composition into at least one section of an electrical cable having a stranded conductor encased in a polymeric insulation jacket, and having an average operating temperature T, the composition comprising:
 (a) at least one organoalkoxysilane functional additive selected from the group consisting of
 (i) a voltage stabilizer-based alkoxysilane compound of Formula 1 
   
       
         
           
           
               
               
           
         
         wherein: 
         m is 1-4; 
         A is a linear or branched alkylene radical containing from 1 to 10 carbon atoms, or one of 
       
       
         
           
           
               
               
           
         
         where S 3 , S 4  and S 5  are linear or branched alkylene radicals containing a total of between 3 and 10 carbon atoms; 
         T is oxygen or sulfur; 
         X is a linear or branched alkyl radical containing from 1 to 5 carbon atoms; 
         Y is C 1 -C 4  acyloxy, C 1 -C 4  alkyloxy, amino, amino-oxy or silyloxy; and n is one, two or three,
 (ii) a hindered amine light stabilizer (HALS)-based alkoxylsilane of formula (XI) 
 
       
       
         
           
           
               
               
           
         
         wherein:
 m+n is a number from 1 to 40, n varies from zero to 50% of the sum m+n; 
 A is —O—: 
 T 1  and T 4  which can be identical or different are methyl, methoxy, ethoxy or OH; 
 T 2  is trimethylene or is also a direct bond if A is —O— and T 1  and T 4  are methyl; 
 T 3  is methyl, C 7 -C 9  alkyl or cyclohexyl; 
 T 5  is C 1 -C 12  alkyl; 
 X 1  is as defined for T 1  or is a group (CH 3 ) 3  SiO—; and 
 X 2  is hydrogen, methyl, ethyl, a group (CH 3 ) 3  Si— or, if n is zero and T 1  and X 1  are methyl, 
 X 2  is also a group of the formula (XIII) 
 
       
       
         
           
           
               
               
           
         
         and, if m+n is a number from 3 to 10, X 1  and X 2  together can also be a direct bond, and 
         (iii) a UV absorber-based alkoxysilane compound of formula (IA) or (IIA) 
       
       
         
           
           
               
               
           
         
         wherein:
 G 1  and G 6  are hydrogen; 
 G 2  and G 7  are independently H, cyano, CF 3 —, fluoro, —CO-G 3 , or E 3 SO 2 —; 
 G 3  is straight or branched chain alkyl of 1 to 24 carbon atoms, straight or branched chain alkenyl of 2 to 18 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbon atoms, phenyl, or said phenyl or said phenylalkyl substituted on the phenyl ring by 1 to 4 alkyl of 1 to 4 carbon atoms; 
 E 1  is phenylalkyl of 7 to 15 carbon atoms, phenyl, or said phenyl or said phenylalkyl substituted on the phenyl ring by 1 to 4 alkyl groups of 1 to 4 carbon atoms each; 
 E 2  and E 9  are independently straight or branched alkyl chain of 1 to 24 carbon atoms, straight or branched chain alkenyl of 2 to 18 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbon atoms, phenyl, or said phenyl or said phenylalkyl substituted on the phenyl ring by 1 to 3 alkyl of 1 to 4 carbon atoms: or E 2  is said alkyl of 1 to 24 carbon atoms or said alkenyl of 2 to 18 carbon atoms substituted by one or more —OH, —OCOE 11 , —OE 4 , —NCO, —NH 2 , —NHCOE 11 , —NHE 4  or —N(E 4 ) 2 , or mixtures thereof, where E 4  is straight or branched chain alkyl of 1 to 24 carbon atoms: or said alkyl or said alkenyl interrupted by one or more —O—, —NH—, or —NE 4 — groups or mixtures thereof and which can be unsubstituted or substituted by one or more —OH, —OE 4 , or —NH 2  groups or mixtures thereof; 
 E 11  is hydrogen, straight or branched chain alkyl of 1 to 18 carbon atoms, straight or branched chain alkenyl of 2 to 18 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, aryl of 6 to 14 carbon atoms or phenylalkyl of 7 to 15 carbon atoms; 
 E 3  is alkyl of 1 to 20 carbon atoms, hydroxyalkyl of 2 to 20 carbon atoms, alkenyl of 3 to 18 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbon atoms, aryl of 6 to 10 carbon atoms or said aryl substituted by one or two alkyls of 1 to 4 carbon atoms or 1,1,2,2-tetrahydroperfluoroalkyl where the perfluoroalkyl moiety is of 6 to 16 carbon atoms; 
 L is methylene; and 
 with the proviso that at least one of E 1 , E 2  and E 9  contains a group -T 1 -Si(OR 2 ) m (R 1 ) 3-n , -T 1 -X—CO—X-T 2 -Si(OR 2 ) n (R 1 ) 3-n , -T 1 -CO—X-T 2 -Si(OR 2 ) n (R 1 ) 3-n , —X-T 1 -Si(OR 2 ) n (R 1 ) 3-n  or —X-T 1 -X—CO—X-T 2 -Si(OR 2 ) n (R 1 ) 3-n ; 
 where, for E 1 , E 2  and E 9 , T 1  and T 2  are independently alkylene of 2 or 3 carbon atoms, R 1  and R 2  are independently alkyl of 1 to 6 carbon atoms or phenyl, n is 1, 2, or 3, and X is —O—, —NE 4 — or —NH—; and 
 (b) at least one catalyst suitable to catalyze hydrolysis and condensation of the at least one functional additive of (a), 
 wherein the at least one organoalkoxysilane functional additive of (a) comprises:
 at least one of the voltage stabilizer-based alkoxysilane compounds of Formula (1) of (i) or 
 at least one of the UV absorber-based alkoxysilane compounds of formula (IA) or (IIA) of (iii), and 
 
 wherein the injected composition provides for both initial permeation of the at least one functional additive into the polymeric insulation, and extended retention of subsequent condensation products of the at least one functional additive in the cable insulation. 
 
       
     
     
         2 . The method of  claim 1 , wherein the cable section has a stranded conductor surrounded by a conductor shield encased in a polymeric insulation jacket with an outer insulation shield, and having an interstitial void volume in the region of the conductor, and wherein injecting comprises injecting the dielectric enhancement fluid composition into the interstitial void volume, and/or into the space between the polymeric insulation jacket and the outer insulation shield. 
     
     
         3 . The method of  claim 1 , wherein the dielectric enhancement fluid composition further comprises
 (c) at least one water-reactive organosilane material selected from
 (i) an organosilane monomer having at least two water-reactive groups, 
 (ii) the organosilane monomer (i) where at least one of the water-reactive groups is substituted with a condensable silanol group, 
 (iii) an oligomer of the above organosilane monomer (i), and/or 
 (iv) a co-oligomer of the above organosilane monomer (i) with a different organosilane monomer, and wherein the catalyst provides for covalent binding of the at least one functional additive of (a) to the at least one water-reactive material (c) upon hydrolysis and condensation thereof. 
   
     
     
         4 . The method of  claim 3 , wherein the organosilane monomer of (i) has a diffusion coefficient at least about 15 times greater than the diffusion coefficient of a tetramer thereof, the diffusion coefficient being determined at the average operating temperature T of the at least one section of the in-service electrical cable. 
     
     
         5 . The method of  claim 3 , wherein the dielectric enhancement fluid composition further comprises:
 (d) a non-water-reactive organic material which has a diffusion coefficient of less than about 10 −9  cm 2 /sec and an equilibrium concentration of at least about 0.005 gm/cm 3  in said polymeric insulation, the diffusion coefficient and the equilibrium concentration being determined at the average operating temperature T; and/or   (e) an organic compound having an equilibrium concentration in the polymeric insulation at 55° C. which is less than 2.25 times the equilibrium concentration at 22° C.   
     
     
         6 . The method of  claim 4 , wherein the dielectric enhancement fluid composition further comprises:
 (d) a non-water-reactive organic material which has a diffusion coefficient of less than about 10 −9  cm 2 /sec and an equilibrium concentration of at least about 0.005 gm/cm 3  in said polymeric insulation, the diffusion coefficient and the equilibrium concentration being determined at the average operating temperature T; and/or   (e) an organic compound having an equilibrium concentration in the polymeric insulation at 55° C. which is less than 2.25 times the equilibrium concentration at 22° C.   
     
     
         7 . The method of  claim 3 , wherein the at least one water-reactive organosilane material is/are organoalkoxysilanes. 
     
     
         8 . The method of  claim 7 , wherein the organoalkoxysilanes are selected from:
 (3-methylphenyl)methyldimethoxysilane,   di(4-methylphenyl)dimethoxysilane,   dimethyldi-n-butoxysilane   (4-methylphenyl)methyldimethoxysilane,   3-cyanopropylmethyldimethoxysilane   3-cyanobutylmethyldimethoxysilane   phenethyltrimethoxysilane,   p-tolylethyl)methyldimethoxysilane,   (p-styrylethyl)trimethoxysilane,   phenylmethyldimethoxysilane   3-(2,4-dinitrophenylamino)propyltriethoxysilane, or   3-(triethoxysilylpropyl) p-nitrobenzamide.   
     
     
         9 . The method of  claim 8 , wherein the organoalkoxysilanes are (p-tolylethyl)methyldimethoxysilane, 3-cyanopropylmethyldimethoxysilane, dimethyldi-n-butoxysilane, or 3-cyanobutylmethyldimethoxysilane. 
     
     
         10 . The method of  claim 4 , wherein the at least one water-reactive organosilane material is/are organoalkoxysilanes. 
     
     
         11 . The method of  claim 10 , wherein the organoalkoxysilanes are selected from:
 (3-methylphenyl)methyldimethoxysilane,   di(4-methylphenyl)dimethoxysilane,   dimethyldi-n-butoxysilane   (4-methylphenyl)methyldimethoxysilane,   3-cyanopropylmethyldimethoxysilane   3-cyanobutylmethyldimethoxysilane   phenethyltrimethoxysilane,   p-tolylethyl)methyldimethoxysilane,   (p-styrylethyl)trimethoxysilane,   phenylmethyldimethoxysilane   3-(2,4-dinitrophenylamino)propyltriethoxysilane, or   3-(triethoxysilylpropyl) p-nitrobenzamide.   
     
     
         12 . The method of  claim 11 , wherein the organoalkoxysilanes are (p-tolylethyl)methyldimethoxysilane, 3-cyanopropylmethyldimethoxysilane, dimethyldi-n-butoxysilane, or 3-cyanobutylmethyldimethoxysilane. 
     
     
         13 . The method of  claim 1 , wherein the organoalkoxysilane functional additives are derived from at least one stabilizing functionality selected from the group consisting of;
 hydroxyphenyl benzotriazole chromophores,   N-Alkoxy 2,2,6,6-tetramethyl piperidine light stabilizers, and   ferrocene backbones.   
     
     
         14 . (canceled) 
     
     
         15 . The method of  claim 1  wherein the voltage stabilizer-based alkoxysilane compound of Formula 1 is at least one organoalkoxysilane compound selected from the group consisting of 
       
         
           
           
               
               
           
         
       
     
     
         16 . The method of  claim 1 , wherein the composition further comprises an organoalkoxysilane functional additive derived from a hindered phenolic antioxidant backbone. 
     
     
         17 . The method of  claim 1 , where the at least one organoalkoxysilane functional additive has a PE retention of at least 0.2%. 
     
     
         18 . The method of  claim 1 , where the at least one organoalkoxysilane functional additive permeates into the cable insulation reaching at least 90% of saturation in less than 500 hours at 55° C. 
     
     
         19 . The method of  claim 1 , where the at least one organoalkoxysilane functional additive has a diffusivity in PE greater than 5.0×10 −9  cm 2 /s at 55° C. and a PE retention of at least 0.40 wt % at 5,000 hours at 55° C. 
     
     
         20 .- 23 . (canceled) 
     
     
         24 . A compound of Formula 1 
       
         
           
           
               
               
           
         
         wherein, 
         m is 1-4; 
         A is a linear or branched alkylene radical containing from 1 to 10 carbon atoms, or one of 
       
       
         
           
           
               
               
           
         
         where S 3 , S 4  and S 5  are linear or branched alkylene radicals containing a total of between 3 and 10 carbon atoms; 
         T is oxygen or sulfur: 
         X is a linear or branched alkyl radical containing from 1 to 5 carbon atoms, and preferably the methyl radical; 
         Y is C 1 -C 4  alkyloxy, amino, amino-oxy or silyloxy, and preferably C 1 -C 2  alkyloxy; and 
         n is one, two or three. 
       
     
     
         25 . The compound of  claim 24 , wherein the compound is at least one selected from the group consisting of 
       
         
           
           
               
               
           
         
       
       and combinations thereof. 
     
     
         26 . The method of  claim 1 , wherein the compound of formula (IA) is 
       
         
           
           
               
               
           
         
       
     
     
         27 . A method for extending the useful life of in-service electrical cable, comprising injecting a dielectric enhancement fluid composition into at least one section of an electrical cable having a stranded conductor encased in a polymeric insulation jacket, and having an average operating temperature T, the composition comprising:
 (a) at least one UV absorber-based alkoxysilane compound of formula (I) or (II)   
       
         
           
           
               
               
           
         
       
       wherein:
 G 1  and G 6  are independently hydrogen or halogen; 
 G 2  and G 7  are independently H, cyano, perfluoroalkyl of 1 to 12 carbon atoms, fluoro, chloro, —CO-G 3 , —COOG 3 , —CONHG 3 , —CON(G 3 ) 2 , E 3 SO—, E 3 SO 2 —, —PO(C 6 H 5 ) 2 , 
 
       
         
           
           
               
               
           
         
       
       O—CO—NH-T 2 -Si(OR 2 ) n (R 1 ) 3-n  or CO—X-T 1 -Si(OR 2 ) n (R 1 ) 3-n ,
 or G 7  is also hydrogen, 
 or G 2  may also be hydrogen when E 1  is a group of formula (IV) or (V) (see below); 
 T 1  and T 2  are independently alkylene of 1 to 18 carbon atoms, preferably alkylene of 2 or 3 carbon atoms, or alkylene-phenylene-alkylene of 8 to 20 carbon atoms; 
 R 1  and R 2  are independently alkyl of 1 to 18 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, aryl of 6 to 10 carbon atoms or phenylalkyl of 7 to 20 carbon atoms, preferably alkyl of 1 to 6 carbon atoms or phenyl; 
 n is 1, 2 or 3; 
 X is —O—, —NE 4 — or —NH—; 
 G 3  is hydrogen, straight or branched chain alkyl of 1 to 24 carbon atoms, straight or branched chain alkenyl of 2 to 18 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbon atoms, phenyl, or said phenyl or said phenylalkyl substituted on the phenyl ring by 1 to 4 alkyl of 1 to 4 carbon atoms; 
 E 1  is hydrogen, straight or branched chain alkyl of 1 to 24 carbon atoms, straight or branched chain alkenyl of 2 to 24 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbon atoms, phenyl, or said phenyl or said phenylalkyl substituted on the phenyl ring by 1 to 4 alkyl of 1 to 4 carbon atoms or by one or more of the following groups -T 1 -Si(OR 2 ) n (R 1 ) 3-n , -T 1 -X—CO—X-T 2 -Si(OR 2 ) n (R 1 ) 3-n , -T 1 -CO—X-T 2 -Si(OR 2 ) n (R 1 ) 3-n , —X-T 1 -Si(OR 2 ) n (R 1 ) 3-n , or —X-T 1 -X—CO—X-T 2 -Si(OR 2 ) n (R 1 ) 3-n , 
 or E 1  is alkyl of 1 to 24 carbon atoms substituted by one or two hydroxy groups, 
 or E 1  is a group of formula (IV) or (V): 
 
       
         
           
           
               
               
           
         
       
       wherein:
 E 27  and E 28  are independently alkyl of 1 to 18 carbon atoms, or cycloalkyl of 5 to 12 carbon atoms, 
 E 22 , E 23 , E 24 , E 25  and E 26  are independently hydrogen, halogen, straight or branched alkyl of 1 to 18 carbon atoms, alkenyl of 2 to 18 carbon atoms, said alkyl or said alkenyl substituted by one or more halogen, —OCOE 11 , —OE 4 , —NCO, —NHCOE 11 , or —NE 7 E 8 , or mixtures thereof, where E 4  is straight or branched chain alkyl of 1 to 24 carbon atoms or straight or branched chain alkenyl of 2 to 18 carbon atoms; or said alkyl or said alkenyl interrupted by one or more —O—, —NH— or —NE 4 — groups or mixtures thereof and which can be unsubstituted or substituted by one or more —OH, —OE 4  or —NH 2 , or mixtures thereof, or 
 E 22 , E 23 , E 24 , E 25  and E 26  are independently phenyl, —OH, —OCOE 11 , —OE 29 , —NCO, —NHCOE 11 , or —NE 7 E 8 , cyano, nitro, perfluoroalkyl of 1 to 12 carbon atoms, —COG 3 , —COOG 3 , —CON(G 3 ) 2 , —CONHG 3 , E 3 S—, E 3 SO—, E 3 SO 2 —, —P(O)(C 6 H 5 ) 2 , —P(O))OG 3 ) 2 , —SO 2 —X 1 -E 29 , where X 1  is —O—, —NH— or —NE 4 —; 
 E 29  is straight or branched chain alkyl of 1 to 24 carbon atoms, straight or branched chain alkenyl of 2 to 18 carbon atoms, said alkyl or said alkenyl substituted by one or more —OH, —OCOE 11 , —OE 4 , —NCO, —NHCOE 11 , —NE 7 E 8 , phthalimido, 
 
       
         
           
           
               
               
           
         
       
       or mixtures thereof, where E 4  is straight or branched chain alkyl of 1 to 24 carbon atoms or alkenyl of 2 to 18 carbon atoms; or said alkyl or said alkenyl interrupted by one or more —O—, —NH— or —NE 4 — groups or mixtures thereof and which can be unsubstituted or substituted by one or more —OH, —OE 4  or —NH 2 , or mixtures thereof, or E 29  is phenyl or phenylalkyl of 7 to 15 carbon atoms, or said phenyl or said phenylalkyl substituted by one to three alkyl groups of 1 to 4 carbon atoms;
 E 2  and E 9  are independently hydrogen, straight or branched alkyl chain of 1 to 24 carbon atoms, straight or branched chain alkenyl of 2 to 18 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbon atoms, phenyl, or said phenyl or said phenylalkyl substituted on the phenyl ring by one to three alkyl of 1 to 4 carbon atoms or by one or more of the following groups -T 1 -Si(OR 2 ) n (R 1 ) 3-n , -T 1 -X—CO—X-T 2 -Si(OR 2 ) n (R 1 ) 3-n , -T 1 -CO—X-T 2 -Si(OR 2 ) n (R 1 ) 3-n , —X-T 1 -Si(OR 2 ) n (R 1 ) 3-n  or —X-T 1 -X—CO—X-T 2 -Si(OR 2 ) n (R 1 ) 3-n ; or E 2  and E 9  are independently said alkyl of 1 to 24 carbon atoms or said alkenyl of 2 to 18 carbon atoms substituted by one or more —OH, —OCOE 11 , —OE 4 , —NCO, —NH 2 , —NHCOE 11 , —NHE 4  or —N(E 4 ) 2 , or mixtures thereof, where E 4  is straight or branched chain alkyl of 1 to 24 carbon atoms; or said alkyl or said alkenyl interrupted by one or more —O—, —NH— or —NE 4 — groups or mixtures thereof and which can be unsubstituted or substituted by one or more —OH, —OE 4  or —NH 2  groups or mixtures thereof, or 
 E 1 , E 2  and E 9  are also independently -T 1 -Si(OR 2 ) n (R 1 ) 3-n , -T 1 -X—CO—X-T 2 -Si(OR 2 ) n (R 1 ) 3-n  or -T 1 -CO—X-T 2 -Si(OR 2 ) n (R 1 ) 3-n ; 
 E 11  is hydrogen, straight or branched chain alkyl of 1 to 18 carbon atoms, straight or branched chain alkenyl of 2 to 18 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, aryl of 6 to 14 carbon atoms or phenylalkyl of 7 to 15 carbon atoms; 
 L is alkylene of 1 to 12 carbon atoms, alkylidene of 2 to 12 carbon atoms, benzylidene, p-xylylene, cycloalkylidene of 5 to 12 carbon atoms or α,α,α′,α′-tetramethyl-m-xylylene; 
 E 3  is alkyl of 1 to 20 carbon atoms, said alkyl substituted by alkoxycarbonyl of 2 to 9 carbon atoms, hydroxyalkyl of 2 to 20 carbon atoms, alkenyl of 3 to 18 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, phenylalkyl of 7 to 15 carbon atoms, aryl of 6 to 10 carbon atoms or said aryl substituted by one or two alkyl of 1 to 4 carbon atoms or 1,1,2,2-tetrahydroperfluoroalkyl where the perfluoroalkyl moiety is of 6 to 16 carbon atoms; 
 E 5  and E 8  are independently the same as E 2 ; or E 5  and E 8  are independently hydrogen,—X-E 1 , —X—CO-E 2 , —X—CO—X 1 , —X-T 1 -Si(OR 2 ) n (R 1 ) 3-n  or X-T 1 -X—CO—X-T 2 -Si(OR 2 ) n (R 1 ) 3-n , where X 1  is —NH-E 4  or —X-E 2 ; 
 with the proviso that at least one of G 2 , G 7 , E 1 , E 2 , E 5 , E 8  and E 9  contains a group -T 1 -Si(OR 2 ) n (R 1 ) 3-n , -T 1 -X—CO—X-T 2 -Si(OR 2 ) n (R 1 ) 3-n , -T 1 -CO—X-T 2 -Si(OR 2 ) n (R 1 ) 3-n , —X-T 1 -Si(OR 2 ) n (R 1 ) 3-n  or —X-T 1 -X—CO—X-T 2 -Si(OR 2 ) n (R 1 ) 3-n ; where T 1  and T 2  are independently alkylene of 1 to 18 carbon atoms or alkylene-phenylene-alkylene of 8 to 20 carbon atoms, and R 1  and R 2  are independently alkyl of 1 to 18 carbon atoms, cycloalkyl of 5 to 12 carbon atoms, aryl of 6 to 10 carbon atoms or phenylalkyl of 7 to 20 carbon atoms, preferably alkyl of 1 to 3 carbon atoms or phenyl, and n is 1, 2 or 3; and 
 (b) at least one catalyst suitable to catalyze hydrolysis and condensation of the at least one functional additive of (a), and 
 wherein the injected composition provides for both initial permeation of the at least one functional additive into the polymeric insulation, and extended retention of subsequent condensation products of the at least one functional additive in the cable insulation. 
 
     
     
         28 . The method of  claim 27 , wherein the compound of formula (I) is at least one compound selected from the group consisting of: 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         
           
           
               
               
           
         
       
       and combinations thereof. 
     
     
         29 . The method of  claim 28 , wherein the compound of formula (I) is