Tree retardant additive composition for polymeric insulation

A method of stabilizing a polymeric insulated electrical conductor against water treeing and electrical treeing which comprises:

• coating an electrical conductor with an insulating effective amount of polymeric insulating composition, said composition consisting essentially of a homogeneous mixture of a polymeric component and a water treeing and electrical treeing inhibitor consisting essentially of (1) a silane having the formula:
• ##STR7## wherein R.sub.1, R.sub.2 and R.sub.3 are the same or different and are (ZC.sub.n H.sub.2n).sub.y XR.sub.4, C.sub.1 to C.sub.8 alkyl, C.sub.1 to C.sub.8 alkoxy, C.sub.1 to C.sub.8 acyloxy, C.sub.2 to C.sub.8 alkenyl, C.sub.6 to C.sub.18 aryl or substituted aryl or C.sub.6 to C.sub.18 aryloxy or substituted aryloxy,
• R.sub.4 is C.sub.1 to C.sub.8 alkyl, C.sub.6 to C.sub.18 aryl or substituted aryl, or hydrogen,
• Z is methylene, O, NH or S;
• X is O, NH or S, n is 1 to 8 and y is 1 to 5 when Z is O and X is O, NH or S, and n is 2 and y is 1 when Z is methylene and X is O, NH or S, and (2) an unsubstituted or an aryl-substituted C.sub.lO -C.sub.20 fatty acid, said aryl substituent being a C.sub.6 to C.sub.18 aryl or substituted aryl, said silane and said fatty acid each being provided in an amount which when combined with the other provides a combined amount which is effective to inhibit water treeing and electrical treeing in said polymeric composition and which does not adversely affect the insulating properties of said polymeric composition, whereby said insulated electrical conductor exhibits water treeing and electrical treeing inhibition when exposed to an environment subject to water treeing and electrical treeing conditions, wherein the ratio of silane to fatty acid is in the range of about 3:1 to about 1:1, respectively.

A water tree and an electrical tree inhibitor composition for polymeric compositions consisting essentially of:

• (a) a silane having the formula:
• ##STR8## wherein R.sub.1, R.sub.2 and R.sub.3 are the same or different and are (ZC.sub.n H.sub.2n).sub.y XR.sub.4, C.sub.1 to C.sub.8 alkyl, C.sub.1 to C.sub.8 alkoxy, C.sub.1 to C.sub.8 acyloxy, C.sub.2 to C.sub.8 alkenyl, C.sub.6 to C.sub.18 aryl or substituted aryl or C.sub.6 to C.sub.18 aryloxy or substituted aryloxy,
• R.sub.4 is C.sub.1 to C.sub.8 alkyl, C.sub.6 to C.sub.18 aryl or substituted aryl or hydrogen,
• Z is methylene, O, NH or S;
• X is O, NH or S, n is 1 to 8 and y is 1 to 5 when Z is O and X is O, NH or S, and n is 2 and y is 1 when Z is methylene and X is O, NH or S, and
• (b) an unsubstituted or an aryl substituted C.sub.1O to C.sub.20 fatty acid, said aryl substituent being a C.sub.6 to C.sub.18 aryl or substituted aryl,
• said silane and said fatty acid each being provided in an amount which when combined with the other provides a combined amount which is effective to inhibit water treeing and electrical treeing in polymeric compositions and which does not adversely affect the electrical insulating properties of polymeric compositions, wherein the ratio of silane to fatty acid is in the range of about 3:1 to about 1:1, respectively.