Artificial turf fiber and method of manufacturing thereof

Abstract

A method of manufacturing an artificial turf fiber includes extruding a polymer mixture through at least one fiber profile opening of an extrusion plate to form an artificial turf fiber, where the fiber profile opening includes first and second end portion openings and a curved middle portion opening has at least one spine opening proximate to at least one end portion opening, allowing the extruded polymer mixture to travel along a distance between the fiber profile opening to a quenching unit, where the at least one spine opening is sized and positioned such that a net polymer mass flow in the extruded polymer mixture from a position of the spine opening to the at least one end portion of the fiber proximate the spine opening occurs before the fiber is quenched, and quenching the extruded polymer mixture in the quenching unit to form the artificial turf fiber.

1 . A method of manufacturing an artificial turf fiber, comprising:
 extruding a polymer mixture through at least one fiber profile opening of an extrusion plate to form an artificial turf fiber, the fiber profile opening including:
 first and second end portion openings, and 
 a curved middle portion opening connected with the first and second end portion openings, the curved middle portion having at least a first spine opening proximate to the first end portion opening and a second spine opening proximate to the second end portion opening; 
   allowing the extruded polymer mixture to travel along a distance between the at least one fiber profile opening of the extrusion plate to a quenching unit, wherein the first and second spine openings are sized and positioned such that a net polymer mass flow in the extruded polymer mixture from a position of the first spine opening to a first end portion of the fiber and from a position of the second spine opening to a second end portion of the fiber occurs before the fiber is quenched; and   quenching the extruded polymer mixture in the quenching unit to form the artificial turf fiber.   
     
     
         2 . The method of  claim 1 ,
 wherein the first spine opening is positioned in the middle portion opening on a first arc length defined by a first angle of less than or equal to 60°, or between 35°-55°, or between 40°-50°, or at 45°, wherein the first arc length is measured along the curved middle portion opening from the first end portion opening,   wherein the second spine opening is positioned in the middle portion opening on a second arc length defined by a second angle of less than or equal to 60°, or between 35°-55°, or between 40°-50°, or at 45°, wherein the second arc length is measured along curved middle portion opening from the second end portion opening.   
     
     
         3 . The method of  claim 1 , wherein the net polymer mass flow mitigates or prevents a reduction in width of the first and second end portions of the quenched fiber in comparison to a width of the end portion openings of the extrusion plate, thereby increasing dimensional stability and/or mitigating or preventing curling of an end of the quenched fiber. 
     
     
         4 . The method of  claim 1 ,
 wherein the fiber comprises a first spine created by extruding the polymer mass through the first spine opening and comprises a second spine created by extruding the polymer mass through the second spine opening.   
     
     
         5 . The method of  claim 4 ,
 wherein the ratio of an area of the first spine opening to an area of the first end portion opening is larger than the ratio of a cross-sectional area of the first spine of the fiber to a cross-sectional area of the first end portion of the quenched fiber, the first end portion of the fiber being created by extruding the polymer mass through the first end portion opening; and   wherein the ratio of an area of the second spine opening to an area of the second end portion opening is larger than the ratio of a cross-sectional area of the second spine of the fiber to a cross-sectional area of the second end portion of the quenched fiber, the second end portion of the fiber being created by extruding the polymer mass through the second end portion opening.   
     
     
         6 . The method of  claim 4 , wherein an amplitude of the first spine of the fiber is less than an amplitude of the first spine opening, and wherein an amplitude of the second spine of the quenched fiber is less than an amplitude of the second spine opening. 
     
     
         7 . The method of  claim 1 , wherein the width of the first end portion opening is larger than the width of the first end portion of the extruded fiber, and wherein the width of the second end portion opening is larger than the width of the second end portion of the extruded fiber. 
     
     
         8 . The method of  claim 1 , wherein the quenched fiber comprises no spines at positions of the first and second spine openings. 
     
     
         9 . The method of  claim 1 , wherein the curved middle portion opening has two opposing longitudinal contours, wherein at least one of the contours comprises or consists of uninterrupted undulations. 
     
     
         10 . The method of  claim 1 , wherein the curved middle portion opening has a shape of one or more sinusoidal waves. 
     
     
         11 . The method of  claim 1 , wherein the curved middle portion opening has a shape of an arc, wherein in particular the shape of the middle portion opening comprises one of: an arc of a segment of a circle, an arc of a segment of an ellipse, an arc of a segment of a horseshoe, an arc of a segment of a U, or an arc of a segment of a Ω. 
     
     
         12 . The method of  claim 11 , wherein a radius of curvature of the middle portion opening decreases from a center of the middle portion opening towards the end portion openings. 
     
     
         13 . The method of  claim 1 , wherein the polymer mixture comprises a polyethylene or a polyethylene-polyamide blend, wherein the quenching unit is a water bath, wherein the distance between the extrusion plate openings and the quenching unit is 3.0-5.0 cm, and wherein a temperature of the water bath is 28° C.-34° C.; or,
 wherein the polymer mixture comprises polyamide as a main polymer component or consists of polyamide, wherein the quenching unit is a water bath, wherein the distance between the extrusion plate openings and the quenching unit is 2.0-4.0 cm, and wherein a temperature of the water bath is 18° C.-20° C. 
 
     
     
         14 . The method of  claim 1 , wherein the polymer mixture is at least a two-phase polymer mixture, wherein a first phase of the polymer mixture comprises a first polymer and a first dye and a second phase of the polymer mixture comprises a second polymer and a second dye, wherein a color of the second dye is different than a color of the first dye, wherein the second polymer is of a same or of a different type as the first polymer, wherein the first and the second phases are immiscible, and wherein the extruded fiber has a marbled appearance. 
     
     
         15 . An extrusion plate for artificial turf fibers, the extrusion plate comprising:
 at least one fiber profile opening, the fiber profile opening including:
 first and second end portion openings, and 
 a curved middle portion opening connected with the first and second end portion openings, having at least a first spine opening proximate to the first end portion opening and a second spine opening proximate to the second end portion opening. 
   
     
     
         16 . Use of the extrusion plate of  claim 15  for mitigating or preventing a reduction in width of end portions of a fiber, thereby increasing dimensional stability and/or for mitigating or preventing curling of an end of the fiber after the fiber is formed upon extruding a polymer mixture through the openings of the extrusion plate. 
     
     
         17 . A system comprising:
 the extrusion plate of  claim 15 ;   at least one fiber formed by extruding a polymer mass through the at least one fiber profile opening, in particular one of the fibers of claims  18 - 19 ; and optionally a quenching unit.   
     
     
         18 . An extruded artificial turf fiber having a cross-sectional profile comprising first and second end portions connected via a curved middle portion, wherein the middle portion comprises at least a first spine proximate to the first end portion and comprises at least a second spine proximate to the second end portion. 
     
     
         19 . The artificial turf fiber of  claim 18 , wherein a width of the curved middle portion as measured between first and second boundary lines of the curved middle portion, excluding a center of the middle portion, is:
 constant along a longitudinal direction of the curved middle portion, or   monotonically increasing along the longitudinal direction of the curved middle portion from either or both end portions towards the center of the middle portion.   
     
     
         20 . An artificial turf comprising:
 a carrier; and   a plurality of artificial turf fibers of  claim 18  integrated into the carrier and protruding therefrom to form the artificial turf.