Blended Elastomer Systems for Specialty Cable Jackets

Ethylene vinyl acetate (EVM), having vinyl acetate levels from 40 to 90%, is a specialty elastomer that is used in specialty cable jackets with the key features providing oil resistance, high heat resistance, and FRNC properties.  The rapid development of oil exploration and the increasing usage of non-fossil energy resources have resulted in more severe service conditions for electrical cables, involve in all of these activities.

In off-shore oil drilling facilities, located north of the Arctic Circle, cable jacket materials have to keep their flexibility during severe low temperature conditions, while being resistant against modern drilling fluids.  For oil exploration in environmentally sensitive areas, easily biodegradable drilling fluids of an ester type have to be used, which are known to cause degradation in contact with rubber parts.

In these cases, one elastomer alone can not meet the specification requirements, thus polymer blends need to be used.  This paper deals with the development of blends of EVM with EPDM or HNBR, with respect to improved mechanical properties, higher degree of fluid resistance, and flexibility at very low temperatures.

Starting formulations have been developed for off-shore drilling, for arctic installation and shipboard, for ester-MUD drilling, for windmill cable, and for solar panel cable applications.