Low shrink and small bend performing drop cable

Patent metadata

Field	Value
Publication number	US-2020386964-A1
Application number	US-202016891604-A
Country	US
Kind code	A1
Filing date	Jun 3, 2020
Priority date	Jun 6, 2019
Publication date	Dec 10, 2020
Grant date	—

Abstract

An optical fiber drop cable. The optical fiber drop cable includes at least one optical fiber and at least one inner tensile element wound around the at least one optical fiber having a laylength of at least 200 mm. The optical fiber drop cable also includes an interior jacket disposed around the at least one inner tensile element and an exterior jacket having an inner surface and an outer surface. The optical fiber drop cable further includes at least one outer tensile element disposed between the interior jacket and the outer surface of the exterior jacket. Each of the at least one outer tensile element has a laylength of at least 1 m. The exterior jacket includes at least one polyolefin, at least one thermoplastic elastomer, and at least one high aspect ratio inorganic filler. The exterior jacket has an averaged coefficient of thermal expansion of no more than 120(10 −6 ) m/mK.

First claim

What is claimed is:

1 . An optical fiber drop cable, comprising:
at least one optical fiber; at least one inner tensile element, wherein each of the at least one inner tensile element is wound around the at least one optical fiber at a laylength of at least 200 mm along a longitudinal axis of the optical fiber drop cable; an interior jacket disposed around the at least one inner tensile element; an exterior jacket having an inner surface and having an outer surface that defines an outermost surface of the optical fiber drop cable; and at least one outer tensile element, wherein the at least one outer tensile element is disposed between the interior jacket and the outer surface of the exterior jacket and wherein each of the at least one outer tensile element has a laylength of at least 1 m along the longitudinal axis of the optical fiber drop cable; wherein the exterior jacket comprises:
at least one polyolefin;
at least one thermoplastic elastomer; and
at least one high aspect ratio inorganic filler;
wherein the exterior jacket has an averaged coefficient of thermal expansion of no more than 120(10 −6 ) m/mK.

2 . The optical fiber drop cable of claim 1 , wherein each of the at least one outer tensile element is disposed between the inner surface of the exterior jacket and the interior jacket.

3 . The optical fiber drop cable of claim 1 , wherein each of the at least one outer tensile element is disposed between the inner surface and the outer surface of the exterior jacket.

4 . The optical fiber drop cable of claim 1 , wherein the at least one outer tensile element includes at least one strand comprising filaments of at least one of an aramid, a carbon fiber, an ultra-high molecular weight polyethylene, an ethylene chlorotrifluoroethylene, a polybenzimidazole, a perfluoroalkoxy, a polytetrafluoroethylene, a polyphenylene sulfide, a liquid crystal polymer, or a polyphenylene benzobisoxazole.

5 . The optical fiber drop cable of claim 1 , wherein the at least one inner tensile element includes at least one strand comprising filaments of at least one of an aramid, a carbon fiber, an ultra-high molecular weight polyethylene, an ethylene chlorotrifluoroethylene, a polybenzimidazole, a perfluoroalkoxy, a polytetrafluoroethylene, a polyphenylene sulfide, a liquid crystal polymer, or a polyphenylene benzobisoxazole.

6 . The optical fiber drop cable of claim 1 , wherein the at least one polyolefin comprises at least one of medium-density polyethylene, high-density polyethylene, low-density polyethylene, linear low-density polyethylene, or polypropylene.

7 . The optical fiber drop cable of claim 1 , wherein the at least one thermoplastic elastomer comprises at least one of ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-octene, ethylene-hexene, ethylene-butene, ethylene-vinyl acetate, or styrene-ethylene-butadiene-styrene.

8 . The optical fiber drop cable of claim 1 , wherein the exterior jacket comprises from 30% to 60% by weight of the at least one thermoplastic elastomer, from 5% to 30% by weight of the at least one high aspect ratio inorganic filler, and with a remainder being the at least one polyolefin and other additives.

9 . The optical fiber drop cable of claim 8 , wherein the other additives comprise at least one of a compatibilizer, a dispersant, or carbon black.

10 . The optical fiber drop cable of claim 1 , wherein the exterior jacket has a yield stress of at least 5 MPa at 23° C., a strain break of at least 400% at 23° C., and an elastic modulus of less than 2000 MPa at −40° C.

11 . The optical fiber drop cable of claim 1 , wherein the exterior jacket has a thermal contraction stress of 6 MPa or less.

12 . The optical fiber drop cable of claim 1 , wherein the at least one high aspect ratio inorganic filler is a plate-like filler, wherein the plate-like filler is comprised of particles with a length to thickness ratio of at least 5:1 on average and with a width to thickness ratio of at least 5:1 on average.

13 . The optical fiber drop cable of claim 12 , wherein the plate-like filler is at least one of mica, talc, montmorillonite, kaolinite, bentonite, or synthetic clay.

14 . The optical fiber drop cable of claim 1 , wherein the high aspect ratio inorganic filler is a rod-like filler having particles with a length to thickness ratio of at least 5:1 on average.

15 . The optical fiber drop cable of claim 14 , wherein the rod-like filler comprises at least one of wood flour, glass fiber, halloysite, wollastonite, magnesium oxysulfate, or a reinforced fiber.

16 . The optical fiber drop cable of claim 1 , wherein the interior jacket comprises a flame retardant, non-corrosive polymer.

17 . A method of manufacturing a drop cable, comprising the steps of:
moving a buffer tube containing at least one optical fiber along a processing line at a rate of at least 200 m/min; winding at least one inner tensile element around the buffer tube, the at least one inner tensile element having a laylength of at least 200 mm; extruding an interior jacket around the at least one inner tensile element; running at least one outer tensile element along a longitudinal axis of the interior jacket; extruding an exterior jacket over or around the at least one outer tensile element, the exterior jacket comprising a polyolefin component, a thermoplastic elastomer component, and an inorganic filler component.

18 . The method of claim 17 , wherein after the step of extruding the exterior jacket, the at least one outer tensile element is disposed between an inner surface of the exterior jacket and an outer surface of the exterior jacket, the inner surface of the exterior jacket contacting the interior jacket of the drop cable.

19 . The method of claim 17 , further comprising the step of selecting at least one of an aramid, a carbon fiber, an ultra-high molecular weight polyethylene, an ethylene chlorotrifluoroethylene, a polybenzimidazole, a perfluoroalkoxy, a polytetrafluoroethylene, a polyphenylene sulfide, a liquid crystal polymer, or a polyphenylene benzobisoxazole for use as filaments in the at least one the inner tensile element and in the at least one outer tensile element.

20 . The method of claim 17 , further comprising the step of selecting the exterior jacket to have a composition of from 30% to 60% by weight of the thermoplastic elastomer component, from 5% to 30% by weight of the inorganic filler component, and with a remainder being the polyolefin component and other additives.

21 . A cable, comprising:
at least one conductor; a buffer tube surrounding the at least one conductor; a first plurality of inner tensile elements, wherein the first plurality of inner tensile elements are wound around the buffer tube at a laylength of at least 500 mm; an interior jacket disposed around the first plurality of inner tensile elements; a second plurality of outer tensile elements; and an exterior jacket having an outer surface defining an outermost surface of the cable, the exterior jacket comprising:
from 30 wt % to 60 wt % of at least one polyolefin;
from 30 wt % to 60 wt % of at least one thermoplastic elastomer; and
from 5 wt % to 30 wt % of at least one inorganic filler;
wherein the second plurality of outer tensile elements is disposed between the outer surface of the exterior jacket and the interior jacket.

22 . The cable of claim 21 , wherein the first plurality of inner tensile elements and the second plurali

Assignees

• Corning Res & Dev Corp

Inventors

• Cheng Xiaole
• Lail Jason Clay

Classifications

• G02B6/4429

  Means specially adapted for strengthening or protecting the cables · CPC title

• G02B6/4432 Primary

  with fibre reinforcements · CPC title

• G02B6/4431 Primary

  with provision in the protective covering, e.g. weak line, for gaining access to one or more fibres, e.g. for branching or tapping (break-out terminations G02B6/4471) · CPC title

• G02B6/4436

  Heat resistant · CPC title