Low cost, high performance, flexible, water-swellable reinforcement for communications cable

Abstract

A low cost, high performance, water-swellable, flexible reinforcement member that can be used for both optical and copper communications cable. The water-swellable reinforcement members made according to the preferred process are more rigid than known reinforcement members, but are less rigid than glass pultruded rods. Communications cables utilizing these members are lightweight, water-swellable and exhibit an improved combination of strength and flexibility compared to traditional communications cables. Further, these communication cables may then be installed into underground ducts using more economical and faster installation techniques.

1 - 19 . (canceled)  
   
   
       20 . A method of forming a flexible reinforcement member for use in a communications cable, the method comprising: 
 providing a plurality of high modulus fibers or fibrous material, said fibers or fibrous material comprising fibers selected from the group consisting of a plurality of sized or unsized aramid fibers and a plurality of sized or unsized poly(p-phenylene-2,6-benzobisoxazole) (PBO) fibers, sized or unsized carbon fibers or sized or unsized high tenacity, linearized polyethylene fiber, and a plurality of sized or unsized high silica glass fibers;    coating said fibers or fibrous material with a low molecular weight primary saturant, said low molecular weight primary saturant having a melting point below approximately 300 degrees Celsius and a melt viscosity of less than approximately 1000 centipoise, wherein the weight of said low molecular weight primary saturant on said fibers or fibrous material comprises between 0.1 and 35 percent of the flexible reinforcement member; and    coating said fibers or fibrous material with a high molecular weight, nonwater-based, water-swellable polymer topcoat.    
   
   
       21 . The method of  claim 20 , wherein coating said fibers or fibrous material with said low molecular weight primary saturant comprises introducing said low molecular weight primary saturant to an application device, said low molecular weight primary saturant comprising a blend of a low molecular weight microcrystalline wax and a high molecular weight, high melt viscosity thermoplastic or thermoplastic elastomeric material, wherein said blend is between at least about 0.1 and about 99.9 percent by weight of said low molecular weight microcrystalline wax and between at least about 0.1 and about 99.9 percent by weight of said high molecular weight, high melt viscosity thermoplastic or thermoplastic elastomeric material.  
   
   
       22 . The method of  claim 21 , wherein introducing said low molecular weight primary saturant to an application device comprises introducing said low molecular weight primary saturant to an immersion bath.  
   
   
       23 . The method of  claim 20 , wherein coating said fibers or fibrous material with said high molecular weight, nonwater-based, water-swellable polymer topcoat comprises introducing said high molecular weight, nonwater-based, water-swellable polymer topcoat onto said low molecular weight primary saturant.  
   
   
       24 . The method of  claim 21 , wherein introducing said low molecular weight primary saturant to said application device and wherein coating said fibers or fibrous material with said high molecular weight, nonwater-based, water-swellable polymer topcoat comprises: 
 introducing said low molecular weight primary saturant to a first application device;    melting said low molecular weight primary saturant within said first application device at a temperature sufficient to maintain said low molecular weight primary saturant at a viscosity of less than about 1000 centipoise;    introducing said fibers or fibrous material to said first application device to coat said low molecular weight primary saturant onto said fibers or fibrous material to form a coated member;    removing said coated member from said first application device;    introducing said coated member to a stripper die to remove an excess of said low molecular weight primary saturant from said fibers or fibrous material;    introducing said coated member to a high molecular weight, nonwater-based, water-swellable polymer topcoat material contained within a second application device to form a top-coated member;    removing said top-coated member from said second application device;    introducing said top-coated member to a second stripper die to remove an excess of said high molecular weight, nonwater-based, water-swellable polymer topcoat material from said top-coated member; and    cooling said top-coated member to form said flexible reinforcement member.    
   
   
       25 . The method of  claim 24 , wherein introducing said low molecular weight primary saturant to a first application device comprises: 
 introducing a low molecular weight mineral wax selected from the group consisting of a low molecular weight microcrystalline wax, a low molecular weight polyalphaolefin wax, a low molecular weight polyethylene wax, a low molecular weight polyethylene wax, a low molecular weight maleated polypropylene polymer and blends thereof.    
   
   
       26 . A method of forming a flexible reinforcement member for use in a communications cable, the method comprising: 
 providing a high modulus fiber material, said fiber material selected from the group consisting of a plurality of sized or unsized aramid fibers and a plurality of sized or unsized poly(p-phenylene-2,6-benzobisoxazole) (PBO) fibers, sized or unsized carbon fibers or sized or unsized high tenacity, linearized polyethylene fiber, and a plurality of sized or unsized high silica glass fibers wherein said high modulus fiber material is pre-coated with a high molecular weight, nonwater-based, water-swellable polymer topcoat; and    coating said fiber material with a low molecular weight primary saturant, said low molecular weight primary saturant having a melting point below approximately 300 degrees Celsius and a melt viscosity of less than approximately 1000 centipoise, wherein the weight of said low molecular weight primary saturant on said fiber material comprises between about 0.1 and about 35 percent of the flexible reinforcement member.    
   
   
       27 . The method of  claim 26 , wherein coating said fiber material with said low molecular weight primary saturant comprises introducing said low molecular weight primary saturant to an application device, said low molecular weight primary saturant comprising a blend of a low molecular weight microcrystalline wax and a high molecular weight, high melt viscosity thermoplastic or thermoplastic elastomeric material, wherein said blend is between at least about 0.1 and about 99.9 percent by weight of said low molecular weight microcrystalline wax and between at least about 0.1 and about 99.9 percent by weight of said high molecular weight, high melt viscosity thermoplastic or thermoplastic elastomeric material.  
   
   
       28 . The method of  claim 27 , wherein coating said fiber material with said low molecular weight primary saturant comprises introducing said low molecular weight primary saturant to an immersion bath.  
   
   
       29 . The method of  claim 28 , wherein the water absorbency for the reinforcement member is between about 349 to about 438 percent by weight.  
   
   
       30 . The method of  claim 26 , wherein said high modulus fiber material is pre-coated with said high molecular weight, nonwater-based, water-swellable polymer topcoat selected from the group consisting of ethylene vinyl acetate (EVA) polymers, block copolymers of polybutylene terepthalate, copolymers of long chain polyether glycols, thermoplastic elastomers, olefins, urethanes, polypropylene, polyethylene, polyurethane, low molecular weight mineral wax, polyacrylamides and blends thereof.  
   
   
       31 . The method of  claim 21 , wherein said high molecular weight, high melt viscosity thermoplastic or thermoplastic elastomeric material includes a styrene butadiene rubber material.  
   
   
       32 . The method of  claim 25 , wherein introducing said coated member to said high molecular weight, nonwater-based, water-swellable polymer topcoat material contained within said second application device comprises introducing said coated member to a high molecular weight, nonwater-based, water-swellable polymer topcoat material selected from the group consisting of ethylene vinyl acetate (EVA) polymers, block copolymers of polybutylene terepthalate, copolymers of long chain polyether glycols, thermoplastic elastomers, olefins, urethanes, polypropylene, polyethylene, polyurethane, low molecular weight mineral wax, polyacrylamides and blends thereof.  
   
   
       33 . The method of  claim 24 , wherein the weight of said low molecular weight primary saturant on said fibers or fibrous material comprises between about 10 and about 35 percent of the flexible reinforcement member and wherein the weight of said high molecular weight, nonwater-based, water-swellable polymer topcoat comprises between about 1 and about 25 percent of the flexible reinforcement member.  
   
   
       34 . The method of  claim 27 , wherein said high molecular weight, high melt viscosity thermoplastic or thermoplastic elastomeric material comprises a styrene butadiene rubber material.