Filling materials for electrical and light waveguide communications cables
AssigneeSiecor Corporation
InventorNaren I. Patel
Life of this patent
Estimating the term…
Abstract
Disclosed are materials used to fill electrical and light waveguide transmitting communications cables to make them waterproof. The filling materials have superior waterproofing, dielectric and handling characteristics and are made from compounds of styrene-ethylene-butylene-styrene, styrene-butadiene-styrene or styrene-isoprene-styrene type block copolymers dissolved in paraffinic or naphthenic type mineral oils with a minimal content of aromatic hydrocarbons, inorganic hollow microspheres and, if desired, an additive such as low molecular weight polyethylene or glycerol hydroxy stearate.
Claims4
A communications cable comprising a plurality of conductors arranged to define a plurality of interstices therebetween, a jacket circumferentially surrounding said conductors, and a filling material filling at least a portion of such interstices, said filling material being comprised of styrene block copolymer rubber, mineral oil and inorganic hollow microspheres, wherein:
- (a) the amount and type of said block copolymer rubber is either:
- (i) 1 to 30 percent by weight of styrene-ethylene-butylene-styrene block copolymer having a styrene to rubber ratio of approximately 0.4 and a specific gravity of approximately 0.9;
- (ii) 7 to 10 percent by weight of styrene-butadiene-styrene block copolymer having a styrene to rubber ratio of approximately 0.39 and a specific gravity of approximately 0.94;
- or
- (iii) 8 to 12 percent by weight of styrene-isoprene-styrene block copolymer having a styrene to rubber ratio of approximately 0.16 and a specific gravity of approximately 0.92;
- (b) wherein said mineral oil is either:
- (i) 60 to 80 percent by weight of paraffinic mineral oil having a viscosity-gravity constant (ASTM D 2501-67) of approximately 0.78 to 0.85 with a minimum of 65 percent paraffinic carbon atoms and a maximum of 5 percent aromatic carbon atoms;
- or
- (ii) 60 to 80 percent by weight of naphthenic mineral oil having a viscosity-gravity constant (ASTM D 2501-67) of approximately 0.78 to 0.85 with a minimum of 35 percent naphthenic carbon atoms and a maximum of 5 percent aromatic carbon atoms;
- and
- (c) said inorganic hollow microspheres are either:
- (i) 1 to 20 percent by weight of inorganic hollow microspheres made from glass, having a particle diameter between 10 and 200 microns and a particle density range of approximately 0.1 to 0.3 g/cm.sup.3 ;
- or
- (ii) 1 to 35 percent by weight of inorganic hollow microspheres made from ceramic materials, having a particle diameter between 60 and 325 microns and a particle density of approximately 0.6 g/cm.sup.3.
Dependencies are inferred from the claim text.