Artificial turf fiber with undulated boundary lines

Abstract

The invention relates to an extruded artificial turf fiber ( 100; 800 - 1200; 2100 - 2500 ). The fiber comprises: first and second end portions ( 1605, 1608 ); and a middle portion ( 2001, 1901 ) having a curved cross-sectional shape, wherein the curved cross-sectional shape is defined by a first boundary line ( 1222 ) and a second boundary line ( 1226 ) opposite the first boundary line, wherein the first boundary line consists of first uninterrupted undulations and the second boundary consists of second uninterrupted undulations, and wherein either: a width of the curved cross-sectional shape as measured between the first and second boundary lines is constant along a length of the curved cross-sectional shape, or the first uninterrupted undulations have a phase offset from the second uninterrupted undulations and/or the first and second uninterrupted undulations have different, equal or modulated spatial frequencies

1 . An extruded artificial turf fiber ( 100 ;  800   1200 ;  2100 - 2500 ) comprising:
 first and second end portions ( 1605 ,  1608 ); and   a middle portion ( 2001 ,  1901 ) having a curved cross-sectional shape,
 wherein the curved cross-sectional shape is defined by a first boundary line ( 1222 ) and a second boundary line ( 1226 ) opposite the first boundary line, 
 wherein the first boundary line consists of first uninterrupted undulations and the second boundary consists of second uninterrupted undulations, and 
 wherein either:
 a width of the curved cross-sectional shape as measured between the first and second boundary lines is constant along a length of the curved cross-sectional shape, or 
 the first uninterrupted undulations have a phase offset from the second uninterrupted undulations and/or the first and second uninterrupted undulations have different, equal or modulated spatial frequencies. 
 
   
     
     
         2 . The extruded artificial turf fiber of  claim 1 , wherein the first and second end portions are thicker than the middle portion. 
     
     
         3 . The extruded artificial turf fiber of  claim 1 , wherein the fiber curved cross-sectional shape as measured between the first and second boundary lines along the length of the curved cross-sectional shape has a non-constant width. 
     
     
         4 . The extruded artificial turf fiber of  claim 3 , wherein widths of the first and second end portions of the fiber are greater than a maximum of the non-constant width of the curved cross-sectional shape of the middle portion. 
     
     
         5 . The extruded artificial turf fiber of  claim 1 , wherein the first and second end portions have curved cross-sectional shapes, and wherein the curved cross-sectional shapes of the first and second end portions are defined by respective boundary lines consisting of third uninterrupted undulations. 
     
     
         6 . The extruded artificial turf fiber of  claim 5 , wherein the third uninterrupted undulations comprise a spatial frequency that is different than the spatial frequencies of the first and/or second uninterrupted undulations. 
     
     
         7 . The extruded artificial turf fiber of  claim 1 , wherein the curved cross-sectional shape of the middle portion 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 Q.   
     
     
         8 . The extruded artificial turf fiber of  claim 1 ,
 wherein the first boundary line is an outer, convex boundary line and the second boundary line is an inner, concave boundary line,   wherein at least 70%, in particular at least 80%, e.g., 100% of the undulations of the outer boundary line are defined by first circles having a same first diameter, and   wherein at least 70%, in particular at least 80%, e.g., 100% of the undulations of the inner boundary line are defined by second circles having a same second diameter.   
     
     
         9 . The extruded artificial turf fiber of  claim 1 , wherein a center of the middle portion of the fiber comprises a thickening that forms a rounded protrusion to at least one side of the fiber. 
     
     
         10 . The extruded artificial turf fiber of  claim 1 , wherein the first boundary line comprises at least one spine that is continuous with neighboring first uninterrupted undulations, wherein the at least one spine is positioned on an outer half of the middle portion of the fiber, and wherein an amplitude of the spine is larger than amplitudes of the neighboring first uninterrupted undulations. 
     
     
         11 . The extruded artificial turf fiber of  claim 1 , wherein the fiber is formed from a polymer mixture, 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 artificial turf fiber has a marbled appearance. 
     
     
         12 . The extruded artificial turf fiber of  claim 11 , wherein the first phase forms polymer beads within the second phase. 
     
     
         13 . The extruded artificial turf fiber of  claim 11 , wherein the polymer mixture further comprises a nucleating agent and/or a compatibilizer. 
     
     
         14 . The extruded artificial turf fiber of  claim 11 , wherein the first polymer is any one of the following: polyamide, polyethylene terephthalate, and polybutylene terephthalate, and wherein the second polymer is any one of the following: polyethylene, polypropylene, and a mixture thereof. 
     
     
         15 . An artificial turf comprising:
 a carrier; and
 a plurality of artificial turf fibers, each artificial turf fiber comprising the extruded artificial turf fiber of  any one of the previous claims  integrated into the carrier and protruding therefrom to form the artificial turf.