Antitracking Aramid Yarn
The invention pertains to an aramid filament yarn provided with a finish composition comprising an organic substance, the amount of organic substance in the finish being selected so that the finish has a conductivity from 0.2 mS/cm to 200 mS/cm, measured as a 50 wt % finish composition in water at 20° C., and the amount of the finish on the yarn being selected so that the yarn has a specific electric resistance from 4×104 to 1.2×107 Ohm.cm. The invention further pertains to an ADSS cable reinforced with bundles of said aramid filament yarn, and to a method for making the ADSS cable.
1 . An aramid filament yarn provided with a finish composition at least comprising an organic substance, the finish having a conductivity from 0.2 mS/cm to 200 mS/cm measured as a 50 wt. % finish composition in water at 20° C., and the yarn having a specific electric resistance from 4×10 4 to 1.2×10 7 Ohm.cm.
2 . The aramid filament yarn of claim 1 wherein the conductivity is from 1 mS/cm to 50 mS/cm.
3 . The aramid filament yarn of claim 1 wherein the specific electric resistance is from 7×10 4 to 1×10 6 Ohm.cm.
4 . The aramid filament yarn of claim 1 wherein the yarn comprises 1 to 30 wt. %, preferably 8 to 22 wt. %, of the finish composition
5 . The aramid filament yarn of claim 1 wherein the organic substance contains at least one statically chargeable acid or base group which may be in the form of a salt.
6 . The aramid filament yarn of claim 5 wherein the organic substance contains at least one of a carboxylate, phosphonate, phosphate, sulfonate, sulfate, and amine group or wherein the organic substance is an imidazole derivate or a quarternary ammonium compound.
7 . The aramid filament yarn of claim 6 wherein the organic substance is a salt of an (alkyl)phosphate, an (alkyl)phosphonate, or is a quarternary ammonium compound.
8 . The aramid filament yarn of claim 1 wherein the aramid is poly(p-phenylene terephthalamide) (PPTA).
9 . The aramid filament yarn of claim 8 wherein the aramid has a modulus of >90 GPa.
10 . An ADSS cable reinforced with bundles of the aramid filament yarn of claim 1 .
11 . The ADSS cable of claim 10 wherein the individual yarn bundles have a linear density of 1000 to 40000 dtex.
12 . The ADSS cable of claim 10 wherein the outer jacket is made of a tracking-resistant polymer.
13 . A method for making the ADSS cable of claim 10 wherein aramid filament yarn is treated with a finish composition at least comprising an organic substance, wherein the finish has a conductivity from 0.2 mS/cm to 200 mS/cm measured as a 50 wt. % finish composition in water at 20° C., and the yarn has a specific electric resistance from 4×10 4 to 1.2×10 7 Ohm.cm, and thereafter embedding bundles of the yarn in a cable comprising components that are usual for ADSS cables.