Waterproof optical fiber cable

Abstract

An optical fiber cable comprising a water blocking layer, an optical fiber disposed inside the water blocking layer and a water blocking material filling the space between the water blocking layer and the optical fiber, the water blocking material comprising a grease having a worked penetration of .[.85.]. .Iadd.300 .Iaddend.to 475 as measured according to ASTM-D-712 at room temperature.

What is claimed is: 
     
       1. An optical fiber cable comprising a water blocking layer, an optical fiber disposed inside the water blocking layer and a water blocking material filling the space between the water blocking layer and the optical fiber, the water blocking material comprising a grease having a worked penetration of .Badd..[.150.]..Baddend. .Iadd.300 .Iaddend.to 450 at room temperature and of at least 85 at -30° C. as measured according to ASTM-D-217, said grease comprising an organic liquid having a viscosity at 40° C. of 6 to 5000° c.st. and 3 to 35 parts by weight per 100 parts by weight of said organic liquid of a thickener. 
     
     
       2. An optical fiber cable as defined in claim 1 wherein the water blocking material further comprises a water absorbing agent in an amount of 10 to 400 parts by weight per 100 parts by weight of the grease. 
     
     
       3. An optical fiber cable as defined in claim 1 wherein the grease is at least one member selected from the group consisting of calcium soap grease, aluminum soap grease, lithium soap grease, calcium complex soap grease, aluminum complex soap grease, bentonite grease, and polyurea grease.