OPTICAL FIBER CABLE PROVIDED WITH STABILIZED WATERBLOCKING MATERIAL

摘要

A cable of this invention includes a core comprising a plurality of coated optical fibers and a filling composition of matter which is disposed about the fibers. Typically, the fibers and the filling material are disposed within a tubular member which is disposed within a sheath system. The sheath system includes longitudinally extending strength members and a plastic jacket. The filling composition which fills interstices in the core is one which includes an oil constituent which is a relatively high molecular weight aliphatic hydrocarbon. The aliphatic hydrocarbon is a synthetic oil such as polyalphaolefin or mineral oil. A relatively large percent by weight of an antioxidant system is used to prevent thermal oxidative degradation of the filling material as well as of materials in contact with the filling material. Advantageously, for stabilization and metal deactivation, the composition includes zinc dialkyldithiophosphate or diaryldithiophosphate. A styrene-ethylene propylene copolymer is also included in order to reduce oil separation of the filling material. A fumed silica is used to impart gel properties to the material.