Techniques for making non-halogenated flame retardant polyolefin tape for use in a cable

Abstract

A tape manufacturing system includes an extruder having a die that defines an elongated opening. The extruder provides molten NHFR polyolefin material through the die. The system further includes a cooling assembly, coupled to the extruder, that receives the extruded NHFR polyolefin material from the extruder and cools the extruded NHFR polyolefin material so that the extruded NHFR polyolefin material hardens into a contiguous sheet, and a cutting assembly that receives the contiguous sheet and cuts the contiguous sheet lengthwise to form multiple parallel feeds of NHFR polyolefin tape. The extruder, the cooling assembly and the cutting assembly operate simultaneously in a continuous manner so that the sheet of NHFR polyolefin material is unbroken between the cooling assembly and the cutting assembly. In general, the system is cost effective since multiple, unlimited length feeds of NHFR polyolefin tape can be made at the same time.

What is claimed is:  
     
         1 . A method for making non-halogenated flame retardant polyolefin tape, comprising the steps of: 
 extruding molten non-halogenated flame retardant polyolefin material through a die that defines an elongated opening;    cooling the extruded non-halogenated flame retardant polyolefin material SO that the extruded non-halogenated flame retardant polyolefin material hardens into a contiguous sheet of non-halogenated flame retardant polyolefin material; and    cutting the contiguous sheet of non-halogenated flame retardant polyolefin material lengthwise to form multiple parallel feeds of non-halogenated flame retardant polyolefin tape, wherein the steps of extruding, cooling and cutting are performed simultaneously in a continuous manner so that the sheet of non-halogenated flame retardant polyolefin material is unbroken before the step of cutting.    
     
     
         2 . The method of  claim 1 , further comprising the step of: 
 simultaneously winding each of the multiple parallel feeds on a respective core to form multiple rolls of non-halogenated flame retardant polyolefin tape.    
     
     
         3 . The method of  claim 2  wherein the step of simultaneously winding includes the step of concurrently forming, as the multiple rolls, multiple spools of non-halogenated flame retardant polyolefin tape.  
     
     
         4 . The method of  claim 2  wherein the step of simultaneously winding includes the step of concurrently forming, as the multiple rolls, multiple pads of non-halogenated flame retardant polyolefin tape.  
     
     
         5 . The method of  claim 1  wherein the die defines the elongated opening such that the elongated opening has a rectangular shape which is at least 150 times longer in length than in width, and wherein the step of extruding includes the step of: 
 pushing the molten non-halogenated flame retardant polyolefin material through the elongated opening having the rectangular shape which is at least 150 times longer in length than in width.  
 
     
     
         6 . The method of  claim 1 , further comprising the steps of: 
 drying non-halogenated flame retardant polyolefin compound to extract moisture from the non-halogenated flame retardant polyolefin compound; and    providing the dried non-halogenated flame retardant polyolefin compound to an extruder to form the molten non-halogenated flame retardant polyolefin material for the step of extruding.    
     
     
         7 . The method of  claim 1 , further comprising the step of: 
 stretching and annealing the feeds of non-halogenated flame retardant polyolefin material in a lengthwise direction to orient molecules within the non-halogenated flame retardant polyolefin material such that tensile strength of the feeds is greater in the lengthwise direction than in a widthwise direction.    
     
     
         8 . A roll of non-halogenated flame retardant polyolefin tape made by a method comprising the steps of: 
 extruding molten non-halogenated flame retardant polyolefin material through a die that defines an elongated opening;    cooling the extruded non-halogenated flame retardant polyolefin material so that the extruded non-halogenated flame retardant polyolefin material hardens into a contiguous sheet of non-halogenated flame retardant polyolefin material;    cutting the contiguous sheet of non-halogenated flame retardant polyolefin material lengthwise to form multiple parallel feeds of non-halogenated flame retardant polyolefin tape, the steps of extruding, cooling and cutting being performed simultaneously in a continuous manner so that the sheet of non-halogenated flame retardant polyolefin material is unbroken before the step of cutting; and    winding a feed of the non-halogenated flame retardant polyolefin tape on a core to form the roll of non-halogenated flame retardant polyolefin tape.    
     
     
         9 . A non-halogenated flame retardant polyolefin tape manufacturing system for making non-halogenated flame retardant polyolefin tape, comprising: 
 an extruder having a die that defines an elongated opening, the extruder providing molten non-halogenated flame retardant polyolefin material through the die;    a cooling assembly, coupled to the extruder, that receives the extruded non-halogenated flame retardant polyolefin material from the extruder and cools the extruded non-halogenated flame retardant polyolefin material so that the extruded non-halogenated flame retardant polyolefin material hardens into a contiguous sheet of non-halogenated flame retardant polyolefin material; and    a cutting assembly that receives the contiguous sheet of non-halogenated flame retardant polyolefin material and cuts the contiguous sheet of non-halogenated flame retardant polyolefin material lengthwise to form multiple parallel feeds of non-halogenated flame retardant polyolefin tape, wherein the extruder, the cooling assembly and the cutting assembly operate simultaneously in a continuous manner so that the sheet of non-halogenated flame retardant polyolefin material is unbroken between the cooling assembly and the cutting assembly.    
     
     
         10 . The non-halogenated flame retardant polyolefin tape manufacturing system of  claim 9 , further comprising: 
 a winding assembly that simultaneously winds each of the multiple parallel feeds on a respective core to form multiple rolls of non-halogenated flame retardant polyolefin tape.    
     
     
         11 . The non-halogenated flame retardant polyolefin tape manufacturing system of  claim 10  wherein the winding assembly is configured to concurrently form, as the multiple rolls, multiple spools of non-halogenated flame retardant polyolefin tape.  
     
     
         12 . The non-halogenated flame retardant polyolefin tape manufacturing system of  claim 10  wherein the winding assembly is configured to concurrently form, as the multiple rolls, multiple pads of non-halogenated flame retardant polyolefin tape.  
     
     
         13 . The non-halogenated flame retardant polyolefin tape manufacturing system of  claim 9  wherein the die of the extruder defines the elongated opening such that the elongated opening has a rectangular shape which is at least 150 times longer in length than in width.  
     
     
         14 . The non-halogenated flame retardant polyolefin tape manufacturing system of  claim 9 , further comprising: 
 a drying assembly, coupled to the extruder, that dries the non-halogenated flame retardant polyolefin compound to extract moisture from the non-halogenated flame retardant polyolefin compound, and provides the dried non-halogenated flame retardant polyolefin compound to the extruder.    
     
     
         15 . The non-halogenated flame retardant polyolefin tape manufacturing system of  claim 9 , further comprising: 
 an orienting and annealing assembly, disposed between the cutting assembly and the winding assembly, that orients and anneals the feeds of non-halogenated flame retardant polyolefin material in a lengthwise direction to orient molecules within the non-halogenated flame retardant polyolefin material such that tensile strength of the feeds is greater in the lengthwise direction than in a widthwise direction.    
     
     
         16 . A method for making a cable, the method comprising the step of: 
 providing a set of conductors;    providing non-halogenated flame retardant polyolefin tape;    wrapping the non-halogenated flame retardant polyolefin tape around the set of conductors; and    extruding a jacket around the wrapped set of conductors to form the cable.    
     
     
         17 . The method of  claim 16  wherein the step of providing the non-halogenated flame retardant polyolefin tape includes the steps of: 
 extruding molten non-halogenated flame retardant polyolefin material through a die that defines an elongated opening;  
 cooling the extruded non-halogenated flame retardant polyolefin material so that the extruded non-halogenated flame retardant polyolefin material hardens into a contiguous sheet of non-halogenated flame retardant polyolefin material; and  
 cutting the contiguous sheet of non-halogenated flame retardant polyolefin material lengthwise to form multiple parallel feeds of non-halogenated flame retardant polyolefin tape.  
 
     
     
         18 . A cable, comprising: 
 a set of conductors;    non-halogenated flame retardant polyolefin tape wrapped around the set of conductors; and    a jacket extruded around the wrapped set of conductors.    
     
     
         19 . The cable of  claim 18  wherein the non-halogenated flame retardant polyolefin tape is made by a method comprising the steps of: 
 extruding molten non-halogenated flame retardant polyolefin material through a die that defines an elongated opening;  
 cooling the extruded non-halogenated flame retardant polyolefin material so that the extruded non-halogenated flame retardant polyolefin material hardens into a contiguous sheet of non-halogenated flame retardant polyolefin material;  
 cutting the contiguous sheet of non-halogenated flame retardant polyolefin material lengthwise to form multiple parallel feeds of non-halogenated flame retardant polyolefin tape; and  
 simultaneously winding each of the multiple parallel feeds on a respective core.  
 
     
     
         20 . A cable manufacturing system for making a cable, comprising: 
 a conductor source that provides a set of conductors;    an non-halogenated flame retardant polyolefin tape source that provides non-halogenated flame retardant polyolefin tape;    a feed assembly that wraps the non-halogenated flame retardant polyolefin tape around the set of conductors; and    an extruding assembly that extrudes a jacket around the wrapped set of conductors to form the cable.    
     
     
         21 . The cable manufacturing system of claim  20  wherein the non-halogenated flame retardant polyolefin tape source includes: 
 an extruder having a die that defines an elongated opening, the extruder providing molten non-halogenated flame retardant polyolefin material through the die;  
 a cooling assembly, coupled to the extruder, that receives the extruded non-halogenated flame retardant polyolefin material from the extruder and cools the extruded non-halogenated flame retardant polyolefin material so that the extruded non-halogenated flame retardant polyolefin material hardens into a contiguous sheet of non-halogenated flame retardant polyolefin material; and  
 a cutting assembly that receives the contiguous sheet of non-halogenated flame retardant polyolefin material and cuts the contiguous sheet of non-halogenated flame retardant polyolefin material lengthwise to form multiple parallel feeds of non-halogenated flame retardant polyolefin tape.