Optical fiber cable jacket with low modulus of elasticity

Abstract

Embodiments of the disclosure relate to a polymer composition. The polymer composition includes from 0% to 80% by weight of a polyolefin component and from 20% to 100% by weight of a thermoplastic elastomer component. The polymer composition has an elastic modulus of less than 1500 MPa at −40° C. as measured using dynamic mechanical analysis according to ASTM D4065. Further, the polymer composition has a coefficient of thermal expansion as averaged over the temperature range of −40° C. to 25° C. of more than 120×10 −6 /K when measured according to ASTM E831, and the polymer composition has a thermal contraction stress of no more than 4.0 MPa at −40° C. as measured using dynamic mechanical analysis. Additionally, embodiments of an optical fiber cable having a cable jacket made of the polymeric composition are disclosed herein.

What is claimed is: 
     
         1 . An optical fiber cable comprising:
 at least one optical fiber;   a polymeric jacket that surrounds the at least one optical fiber;   wherein the polymeric jacket is formed at least in part from a polymer composition comprising:
 from 0% to 80% by weight of a polyolefin component; 
 from 20% to 100% by weight of a thermoplastic elastomer component; 
 wherein the polymer composition has an elastic modulus of at most 1500 MPa at −40° C. as measured using dynamic mechanical analysis according to ASTM D4065; 
 wherein the polymer composition has a coefficient of thermal expansion as averaged over the temperature range of −40° C. to 25° C. of at least 120×10 −6 /K when measured according to ASTM E831; and 
 wherein the polymer composition has a thermal contraction stress of at most 4.0 MPa at −40° C. as measured using dynamic mechanical analysis. 
   
     
     
         2 . The optical fiber cable of  claim 1 , wherein the polyolefin component comprises at least one of medium-density polyethylene, high-density polyethylene, low-density polyethylene, linear low-density polyethylene, or polypropylene. 
     
     
         3 . The optical fiber cable of  claim 1 , wherein the thermoplastic elastomer component comprises at least one of olefin block copolymers, olefin random copolymers, ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-octene, ethylene-hexene, ethylene-butene, ethylene-vinyl acetate, or styrene-ethylene-butadiene-styrene. 
     
     
         4 . The optical fiber cable of  claim 1 , wherein the coefficient of thermal expansion is at least 160×10 −6 /K. 
     
     
         5 . The optical fiber cable of  claim 4 , wherein the coefficient of thermal expansion is at most 300×10 −6 /K. 
     
     
         6 . The optical fiber cable of  claim 4 , wherein the polymer composition has a thermal contraction stress of at most 2.0 MPa. 
     
     
         7 . The optical fiber cable of  claim 1 , wherein the polymer composition comprises up to 40% by weight of a filler component. 
     
     
         8 . The optical fiber cable of  claim 7 , wherein the filler component comprises a flame retardant additive. 
     
     
         9 . The optical fiber cable of  claim 8 , wherein the flame retardant additive comprises at least one of alumina trihydrate, magnesium hydroxide, boehmite, CaCO 3 , or an intumescent material. 
     
     
         10 . The optical fiber cable of  claim 7 , wherein the filler component comprises at least 2.5% by weight of carbon black for UV protection. 
     
     
         11 . The optical fiber cable of  claim 1 , wherein the polymeric jacket is coextruded with an outer layer of at least one of linear low-density polyethylene, medium-density polyethylene, or high-density polyethylene, and wherein the outer layer is thinner than the polymeric jacket. 
     
     
         12 . The optical fiber cable of  claim 1 , further comprising a buffer tube and a plurality of aramid yarns, wherein the at least one optical fiber is arranged in the buffer tube and wherein the plurality of aramid yarns are disposed around the buffer tube. 
     
     
         13 . The optical fiber cable of  claim 12 , wherein the optical fiber cable does not comprise any glass yarns used as a tensile element. 
     
     
         14 . An optical fiber drop cable comprising:
 at least one optical fiber;   a buffer tube disposed around the at least one optical fiber;   a plurality of tensile yarns disposed around the buffer tube;   a polymeric jacket disposed around the plurality of tensile yarns;   wherein the polymeric jacket is formed at least in part from a polymer composition consisting essentially of:
 from 0% to 80% by weight of a polyolefin component; 
 from 20% to 100% by weight of a thermoplastic elastomer component; and 
 from 0% to 40% by weight of a filler component; 
 wherein the polymer composition has an elastic modulus of 200 MPa to 1500 MPa at −40° C. as measured using dynamic mechanical analysis according to ASTM D4065; and 
 wherein the polymer composition has a coefficient of thermal expansion as averaged over the temperature range of −40° C. to 25° C. of 120×10 −6 /K to 300×10 −6 /K when measured according to ASTM E831. 
   
     
     
         15 . The optical fiber drop cable of  claim 14 , wherein the polymer composition has a thermal contraction stress of at most 4.0 MPa at −40° C. as measured using dynamic mechanical analysis.