Wrapping yarn for artificial turf

Abstract

An artificial turf wrapping yarn made of polyethylene or polyethylene-polyamide polymer mixture with a compatibilizer. The wrapping yarn is adapted for wrapping around a plurality of turf fiber monofilaments to form a bundle of the turf fiber monofilaments and protect their integrity during securing the bundle of the turf fiber monofilaments to a carrier of the artificial turf.

1 . An artificial turf wrapping yarn made of polyethylene or a polyethylene-polyamide polymer mixture with a compatibilizer. 
     
     
         2 . The wrapping yarn of  claim 1 , wherein the wrapping yarn is adapted for wrapping a plurality of turf fiber monofilaments to form a bundle of the turf fiber monofilaments and protect their integrity during securing the bundle of the turf fiber monofilaments to a carrier of the artificial turf. 
     
     
         3 . The wrapping yarn of  claim 2 , wherein the plurality of the turf fiber monofilaments are made of the same type of material like the wrapping yarn, in particular polyethylene, or a polyethylene-polyamide polymer mixture with a compatibilizer. 
     
     
         4 . The wrapping yarn of  claim 1 ,
 wherein the polyethylene in the polyethylene wrapping yarn comprises HDPE or HMPE or a combination thereof,   wherein in particular the polyethylene-polyamide polymer mixture in the wrapping yarn or in the turf fiber monofilaments comprises 70% to 95%, or 80% to 90% PE by weight, 0.1% to 2% by weight of a compatibilizing agent, and the balance of the polymer mixture is polyamide.   
     
     
         5 . The wrapping yarn of  claim 1 , wherein the wrapping yarn comprises a bundle of individual wrapping yarn monofilaments, preferably from about 20 to 50 individual wrapping yarn monofilaments, more preferably 30 to 40 individual wrapping yarn monofilaments. 
     
     
         6 . The wrapping yarn of  claim 5 , wherein each of the individual wrapping yarn monofilaments has a cross section with a diameter of less than 50 micrometer, in particular 20 to 30 micrometers. 
     
     
         7 . The wrapping yarn of  claim 1 , wherein the wrapping yarn is texturized, wherein in particular the wrapping yarn is texturized so that it shrinks upon being cut and temperature treated—starting from a maximum expanded state—to less than 60% of its original length when wrapping the fiber bundle, in particular to less than 50% of its original length, for example to less than 30% or less than 20% of its original length. 
     
     
         8 . The wrapping yarn of  claim 1 , wherein the wrapping yarn is a bundle of multiple wrapping yarn monofilaments, the said monofilaments being formed by extruding the individual wrapping yarn monofilaments from an extruder through a plurality of extrusion nozzle openings and bundling the extruded individual wrapping yarn monofilaments to form the wrapping yarn. 
     
     
         9 . The wrapping yarn of  claim 1 , wherein the wrapping yarn has a weight of less than 50 g, preferably less than 40 g per 10.000 m of the wrapping yarn. 
     
     
         10 . The wrapping yarn of  claim 1 , wherein the wrapping yarn is made of polyethylene which
 has an MFI (Melt flow index/melt flow rate) of at least 1.0 g/min, in particular from 1.0 g/min to 200 g/min, in particular from 3.0 g/min to 50 g/min, in particular from 5.0 g/min to 30 g/min, in particular from 15.0 g/min to 30 g/min measured according to the ISO standard 1133-1 at 190° C. and a weight of 2.16 kg, and/or   has a density below 0.925 g/cm 3 .   
     
     
         11 . The wrapping yarn of  claim 1 , wherein the wrapping yarn comprises a nucleating agent, in particular sorbic acid. 
     
     
         12 . The wrapping yarn of  claim 1 , wherein the wrapping yarn comprises a radically crosslinked polyethylene. 
     
     
         13 . An artificial turf fiber bundle, comprising:
 a plurality of turf fiber monofilaments, the plurality of artificial turf fiber preferably comprising at least 3, more preferably 5 to 10, and most preferably 6 to 8 turf fiber monofilaments, and   the wrapping yarn of  claim 1 , wherein the wrapping yarn is wrapped around the plurality of the turf fiber monofilaments such that a bundle of artificial turf fiber is formed,   wherein the turf fiber monofilaments comprise polyethylene or a polyethylene-polyamide mixture with a compatibilizer.   
     
     
         14 . An artificial turf comprising:
 a plurality of artificial turf fibers which are integrated in bundles at puncture points in a carrier, and   the wrapping yarn according to  claim 1 ,   wherein the wrapping yarn is integrated into the carrier at the puncture points.   
     
     
         15 . The artificial turf of  claim 14 , wherein the length of the wrapping yarn between the puncture points and the ends of the wrapping yarn comprises a plurality of texturized wrapping yarn fibers, and/or wherein in particular the wrapping yarn fibers have a length of less than 60% of the length of the artificial turf fibers, in particular of 30% of the length of the artificial turf fibers, preferably to less than 20% of the length of the artificial turf fibers, and more preferably to less than 10% of the length of the artificial turf fibers. 
     
     
         16 . A method for manufacturing a wrapping yarn for artificial turf, the method comprising:
 extruding polyethylene or a polyethylene-polyamide mixture with a compatibilizer, into a plurality of monofilaments; and   bundling the plurality of monofilaments together to form the wrapping yarn.   
     
     
         17 . The method of  claim 16 , wherein the extrusion of the wrapping yarn monofilaments is performed at a temperature of at least 190° C., in particular at least 230° C., in particular 240° C. to 260° C. 
     
     
         18 . A method of manufacturing artificial turf by using the wrapping yarn of  claim 1  or the artificial turf fiber bundle of  claim 13 , the method comprising:
 providing a plurality of turf fiber monofilaments; 
 using the wrapping yarn to wrap around a plurality of turf fiber monofilaments to form a continuous turf fiber bundle of turf fiber monofilaments wrapped with the wrapping yarn; 
 tufting the continuous turf fiber bundle through a carrier to form loops of the turf fiber bundle on a front side of the carrier; and 
 cutting the loops to form a plurality of free end fibers per loop pointing out from the carrier to form a grass-like artificial turf surface, 
 wherein in particular the wrapping yarn that is wrapped around each bundle upon being cut shrinks to less than 30% of its original length when wrapping the fiber bundle, preferably to less than 20% of its original length, and more preferably to less than 10% of its original length. 
 
     
     
         19 . The method of  claim 18 , further comprising:
 after the tufting, applying a liquid backing onto a lower side of the carrier for fixing portions of the artificial turf fibers and portions of the wrapping yarn in the carrier, the lower side being the side opposed to the side to which the cut artificial turf fibers emerge; and   applying heat for letting the applied liquid backing solidify.