Methods and systems for manufacturing yarns for synthetic turf

Abstract

Systems and methods for manufacturing synthetic yarns for synthetic turf. The systems and methods include rollers for advancing a plastic sheet forward through a manufacturing process. The plastic sheet is cooled and heated on opposing sides by alternating temperature rollers to pre-form the plastic sheet such that subsequent synthetic yarns made from the sheet will have a curled shape. The plastic sheet is then cut longitudinally by a plurality of slitting blades along the length of the sheet to form a plurality of single strand synthetic yarns. A drawing device then draws and stretches the single strand synthetic yarns to a desired width and thickness, wherein the drawing device includes a drawing oven for heating the yarns, and a plurality of drawing rollers for pulling and stretching the heated yarns. The final product drawn yarns comprise sealed, smooth yarns with desirable rounded edges and a curled tip.

1 . A system for manufacturing single strand synthetic yarns for synthetic turf, comprising:
 a plurality of rollers for advancing a sheet of plastic along a predetermined path within the apparatus;   a slitting component for receiving the plastic sheet and slitting the plastic sheet longitudinally along the length of the sheet to form a plurality of single strand synthetic yarns as the plastic sheet advances along the predetermined path; and   a drawing component positioned along the predetermined path after the slitting component for pulling the plurality of single strand synthetic yarns under tension and heat to stretch and thin the yarns and further to round the edges of the yarns.   
   
   
       2 . The system of  claim 1 , further comprising a plurality of differential temperature rollers for alternatively heating and cooling opposing sides of the plastic sheet before the plastic sheet is cut by the slitting component. 
   
   
       3 . The system of  claim 2 , wherein the plurality of differential temperature rollers alternatively cool one side of the plastic sheet to a temperature of about 25° C. and heat the other side of plastic sheet to a temperature of about 35° C. 
   
   
       4 . The system of  claim 2 , further comprising a reheating component for reheating the plurality of single strand synthetic yarns after the yarns have passed through the drawing component and after the yarns have been cut to predetermined lengths, wherein the reheating causes the ends of the cut yarns to curl. 
   
   
       5 . The system of  claim 1 , wherein the slitting component comprises a plurality of slitting blades that engage and continuously cut the plastic sheet into the plurality of single strand synthetic yarns as the sheet advances along the predetermined path. 
   
   
       6 . The system of  claim 5 , wherein the plurality of slitting blades are spaced apart at a predetermined equal distance between about 1.0 mm to about 6.0 mm. 
   
   
       7 . The system of  claim 5 , wherein the plurality of slitting blades are spaced apart at a plurality of different distances to create single strand synthetic yarns of a corresponding plurality of widths. 
   
   
       8 . The system of  claim 5 , further comprising a first pulling and tensioning roller positioned to contact the plurality of single strand synthetic yarns at a distance less than or equal to 1.0 inch after the slitting blades to maintain tension on the yarns. 
   
   
       9 . The system of  claim 8 , further comprising a second pulling and tensioning roller positioned opposite the first pulling and tensioning roller such that the plurality of single strand synthetic yarns are pinched between the first pulling and tensioning roller and the second pulling and tensioning roller to maintain tension on the yarns. 
   
   
       10 . The system of  claim 9 , wherein the second pulling and tensioning roller is positioned at a predetermined distance from the first pulling and tensioning roller along the predetermined path. 
   
   
       11 . The system of  claim 1 , wherein the plastic sheet advances through the slitting component at a speed of about 16.6 m/min. 
   
   
       12 . The system of  claim 1 , wherein the drawing component includes a drawing oven for heating the plurality of single strand synthetic yarns and a plurality of drawing rollers adapted to stretch and shape the plurality of single strand synthetic yarns. 
   
   
       13 . The system of claim.  12 , wherein the drawing oven heats the single strand synthetic yarns to a temperature between about 90° C. to about 110° C. 
   
   
       14 . The system of  claim 12 , wherein at least one of the plurality of drawing rollers heats the plurality of single strand synthetic yarns and wherein at least one of the plurality of drawing rollers cools the plurality of single strand synthetic yarns after the yarns exit the drawing oven. 
   
   
       15 . The system of  claim 14 , wherein the plurality of single strand synthetic yarns are heated by a heated drawing roller to a temperature between about 90° C. to about 110° C. and are cooled by a cooled drawing roller to a temperature of about 25° C. 
   
   
       16 . The system of  claim 1 , wherein the drawing component pulls the plurality of single strand synthetic yarns under tension with a draw ratio of about 6:1. 
   
   
       17 . The system of  claim 1 , wherein the plastic sheet provided to the slitting component has a width between about 0.5 m to about 3.0 m and a thickness between about 50 microns to about 5.00 microns. 
   
   
       18 . The system of  claim 1 , wherein the plurality of single strand synthetic yarns have a width between about 0.5 mm to about 3.0 mm and a thickness between about 25 microns to about 150 microns after the yarns have been formed by the slitting component and heated and stretched by the drawing component. 
   
   
       19 . The system of  claim 1 , further comprising a winder to wind the plurality of single strand synthetic yarns together to form multiple strand synthetic yarn combinations after the yarns have been drawn by the drawing component and a twister to wrap the multiple strand synthetic yarn combinations around a flanged spool for further processing. 
   
   
       20 . The system of  claim 1 , wherein the plastic sheet comprises linear low density polyethylene (LLDPE), polypropylene, nylon, or any combination thereof. 
   
   
       21 . A system for manufacturing single strand synthetic yarns for synthetic turf, comprising:
 a plurality of pulling and tensioning rollers for advancing a plastic sheet along a predetermined path within the system;   a series of alternating temperature rollers for heating and cooling opposing sides of the plastic sheet as the sheet advances along the predetermined path;   a plurality of slitting blades for slitting the plastic sheet to form a plurality of single strand synthetic yarns after the plastic sheet has passed around the alternating temperature rollers, wherein the slitting blades engage and continuously cut the plastic sheet as the sheet is advanced along the predetermined path;   a drawing oven for heating the plurality of single strand synthetic yarns once the yarns have been cut by the slitting blades, wherein the drawing oven heats the plurality of single strand synthetic yarns to assist in a heated stretching of the yarns; and   a series of drawing rollers adapted for tensionally pulling the plurality of single strand synthetic yarns through the drawing oven to produce the heated stretching of the yarns, wherein the heated stretching elongates and shapes the yarns and additionally rounds the edges of the yarns.   
   
   
       22 . The system of  claim 21 , further comprising a reheating component for reheating the plurality of single strand synthetic yarns after the yarns have passed through the series of drawing rollers and after the yarns have been cut to predetermined lengths, wherein the reheating causes the ends of the cut yarns to curl. 
   
   
       23 . The system of  claim 21 , wherein at least one pulling and tensioning roller is positioned to contact the plurality of single strand synthetic yarns at a distance less than or equal to 1.0 inch after the slitting blades to maintain tension on the yarns. 
   
   
       24 . The system of  claim 21 , wherein at least one drawing roller in the series of drawing rollers heats the plurality of single strand synthetic yarns and wherein at least one drawing roller in the series of drawing rollers cools the plurality of single strand synthetic yarns after the yarns exit the drawing oven. 
   
   
       25 . The system of  claim 21 , wherein the plastic sheet comprises linear low density polyethylene (LLDPE), polypropylene, nylon, or any combination thereof. 
   
   
       26 . A method for manufacturing single strand synthetic yarns for synthetic turf, comprising the steps of:
 advancing a plastic sheet along a predetermined path;   slitting the plastic sheet longitudinally into a plurality of single strand synthetic yarns, wherein the plastic sheet is slit at a set point along the predetermined path as the plastic sheet advances along the predetermined path; and, thereafter,   drawing the plurality of single strand synthetic yarns under tension and heat to stretch and thin the yarns and further to round the edges of the yarns.   
   
   
       27 . The method of  claim 26 , further comprising the step of alternatively heating and cooling opposing sides of the plastic sheet before the sheet is slit into the plurality of single strand synthetic yarns. 
   
   
       28 . The method of  claim 27 , wherein the plastic sheet is alternatively cooled to a temperature of about 25° C. and heated to a temperature of about. 35° C. 
   
   
       29 . The method of  claim 27 , further comprising the step of cutting the plurality of single strand synthetic yarns to desired lengths after the yarns have been drawn and attaching the cut single strand synthetic yarns to a backing. 
   
   
       30 . The method of  claim 29 , further comprising the step of reheating the cut single strand synthetic yarns before the yarns have been attached to the backing to produce a curled shape in the yarns. 
   
   
       31 . The method of  claim 29 , further comprising the step of reheating the cut single strand synthetic yarns after the yarns have been attached to the backing to produce a curled shape in the yarns. 
   
   
       32 . The method of  claim 26 , wherein the plastic sheet advances along the predetermined path at a speed of about 16.6 m/min. 
   
   
       33 . The method of  claim 26 , wherein the step of slitting the plastic sheet includes continuously slitting the sheet at the set point as the plastic sheet advances along the predetermined path. 
   
   
       34 . The method of  claim 26 , wherein before the plastic sheet is slit the sheet has a width between about 0.5 m to about 3.0 m and a thickness between about 50 microns to about 500 microns. 
   
   
       35 . The method of  claim 26 , wherein the plurality of single strand synthetic yarns are slit such that each single strand synthetic yarn has a width of between about 1.0 mm to about 6.0 mm before the plurality of single strand synthetic yarns are drawn. 
   
   
       36 . The method of  claim 26 , wherein the plurality of single strand synthetic yarns have a width between about 0.5 mm to about 3.0 mm and a thickness between about 25 microns to about 150 microns after the yarns have been slit and drawn. 
   
   
       37 . The method of  claim 26 , further comprising the step of contacting and pulling the plurality of single strand synthetic yarns along the predetermined path immediately after the yarns have been slit to maintain tension on the yarns as the yarns progress along the predetermined path, wherein the contacting and pulling occurs at a point along the predetermined path less than or equal to 1.0 inch after the set point at which the plurality of single strand synthetic yarns are slit. 
   
   
       38 . The method of  claim 26 , wherein the plurality of single strand synthetic yarns are drawn at a draw ratio of about 6:1. 
   
   
       39 . The method of  claim 26 , wherein the plurality of single strand synthetic yarns are heated to a temperature between about 90° C. to about 110° C. while being drawn. 
   
   
       40 . The method of  claim 26 , wherein the step of drawing the plurality of single strand synthetic yarns further comprises the step of cooling the plurality of single strand synthetic yarns after the yarns have been heated and stretched. 
   
   
       41 . The method of  claim 40 , wherein the plurality of single strand synthetic yarns are cooled to a temperature of about 25° C. 
   
   
       42 . The method of  claim 26 , further comprising the step of winding the plurality of single strand synthetic yarns together to form multiple strand synthetic yarn combinations after the yarns have been drawn and twisting the multiple strand synthetic yarn combinations together for further processing. 
   
   
       43 . The method of  claim 26 , wherein the plastic sheet comprises linear low density polyethylene (LLDPE), polypropylene, nylon, or any combination thereof. 
   
   
       44 . A single strand synthetic yarn manufactured according to the method described in  claim 26 . 
   
   
       45 . A method for manufacturing single strand synthetic yarns for synthetic turf, comprising the steps of:
 advancing a plastic sheet along a predetermined path;   alternatively heating and cooling opposing sides of the plastic sheet;   slitting the plastic sheet into a plurality of single strand synthetic yarns after the opposing sides of the plastic sheet have been alternatively heated and cooled, wherein the plastic sheet is continuously slit at a set point along the predetermined path as the plastic sheet advances along the predetermined path;   heating the plurality of single strand synthetic yarns once the yarns have been cut from the plastic sheet by the slitting blades, wherein the yarns are heated to assist in a heated stretching of the yarns; and, thereafter   pulling the plurality of single strand synthetic yarns under tension and heat to generate the heated stretching of the yarns, wherein the heated stretching elongates and shapes the yarns and additionally rounds the edges of the yarns.   
   
   
       46 . The method of  claim 45 , further comprising the step of cutting the plurality of single strand synthetic yarns to desired lengths after the yarns have been pulled under tension and heat and attaching the cut single strand synthetic yarns to a backing. 
   
   
       47 . The method of  claim 46 , further comprising the step of reheating the cut single strand synthetic yarns before the yarns have been attached to the backing to produce a curled shape in the yarns. 
   
   
       48 . The method of  claim 46 , further comprising the step of reheating the cut single strand synthetic yarns after the yarns have been attached to the backing to produce a curled shape in the yarns. 
   
   
       49 . The method of  claim 45 , further comprising the step of contacting and pulling the plurality of single strand synthetic yarns along the predetermined path immediately after the yarns are slit to maintain tension on the yarns as the yarns progress along the predetermined path, wherein the contacting and pulling occurs at a point along the predetermined path less than or equal to 1.0 inch after the set point at which the plurality of single strand synthetic yarns are slit. 
   
   
       50 . The method of  claim 45 , wherein the step of pulling the plurality of single strand synthetic yarns under tension and heat further comprises the step of cooling the plurality of single strand synthetic yarns after the yarns have been heated and stretched. 
   
   
       51 . The method of  claim 45 , wherein the plastic sheet comprises linear low density polyethylene (LLDPE), polypropylene, nylon, or any combination thereof. 
   
   
       52 . A single strand synthetic yarn manufactured according to the method described in  claim 45 .