Search

US-20260125858-A1 - ARTIFICIAL TURF WITH TRACTION CONTROL AGENT

US20260125858A1US 20260125858 A1US20260125858 A1US 20260125858A1US-20260125858-A1

Abstract

Disclosed is an artificial turf fiber comprising: 1.0 to 10.0 wt % of the fiber a modifier polymer material, the remainder of the fiber including a base polymer material and at least one additive, wherein the modifier polymer material is polyethylene selected from an ultra-low density polyethylene (ULDPE) or a low density polyethylene (LDPE) or a combination thereof, wherein the base polymer material is polyamide, or polyester, or a combination thereof, and wherein the at least one additive includes a compatibilizer.

Inventors

  • Stephan Sick
  • Dario Grochla
  • Anthony David DANIELL

Assignees

  • POLYTEX SPORTBELAGE PRODUKTIONS-GMBH
  • SYNTHETIC TURF RESOURCES

Dates

Publication Date
20260507
Application Date
20241115
Priority Date
20241107

Claims (18)

  1. 1 . An artificial turf fiber comprising: a modifier polymer material in an amount of 1.0 to 10.0% by weight of the fiber, the remainder of the fiber including a base polymer material and at least one additive, wherein the modifier polymer material is polyethylene selected from an ultra-low density polyethylene (ULDPE) or a low density polyethylene (LDPE) or a combination thereof, wherein the base polymer material is polyamide, or polyester, or a combination thereof, and wherein the at least one additive includes a compatibilizer.
  2. 2 . The artificial turf fiber of claim 1 , wherein the compatibilizer forms a boundary layer between the modifier polymer material and the base polymer material, and wherein the modifier polymer material forms elongated thread-like structures inside a continuous phase of the base polymer material.
  3. 3 . The artificial turf fiber of claim 1 , wherein the compatibilizer includes ethylene ethyl acrylate (“EEA”).
  4. 4 . The artificial turf fiber of claim 1 , wherein the compatibilizer includes a polyethylene grafted with maleic anhydride or a combination of polyethylene grafted with maleic anhydride and ethylene ethyl acrylate (“EEA”) or any combination thereof.
  5. 5 . The artificial turf fiber of claim 4 , wherein the polyethylene grafted with maleic anhydride is an ULDPE or LDPE, and more particularly is the same as the polyethylene that is the modifier polymer material.
  6. 6 . The artificial turf of claim 1 , wherein the artificial turf fiber comprises 2.0 to 9.0%, or 2.0 to 8.0%, or 2.0 to 7.0%, or 3.0 to 7.0% of the modifier polymer material.
  7. 7 . The artificial turf fiber of claim 1 , wherein the modifier polymer material is ULDPE.
  8. 8 . The artificial turf fiber of claim 1 , wherein base polymer is one of PA6, PA66, PA11, PA12, PA46, PA610 and PA612, or wherein the base polymer material is polyester homopolymer with a melting point of 160 to 170° C.
  9. 9 . The artificial turf fiber of claim 1 , wherein the compatibilizer is any one of the following: a maleic acid grafted on polyethylene or polyamide; a maleic anhydride grafted on free radical initiated graft copolymer of polyethylene, SEBS, EVA, EPD, or polyproplene with an unsaturated acid or its anhydride such as maleic acid, glycidyl methacrylate, ricinoloxazoline maleinate; a graft copolymer of SEBS with glycidyl methacrylate, a graft copolymer of EVA with mercaptoacetic acid and maleic anhydride; a graft copolymer of EPDM with maleic anhydride; a graft copolymer of polypropylene with maleic anhydride; a polyolefin-graft-polyamide; a polyolefin-graft-polyethylene; a polyolefin-graft-polyamide; a polyacrylic acid type compatibilizer; a polyethylene grafted with maleic anhydride; and ethylene ethyl acrylate, EEA.
  10. 10 . The artificial turf fiber of claim 1 , wherein the compatibilizer is polyethylene grafted with maleic anhydride having a melting point of 105° C.-135° C. as measured by ASTM D3418 or ISO 3146, a crystallization point of 90° C.-110° C. as measured by ASTM D3418, or ISO 3146, a cat softening point of 90° C.-100° C. as measured by ASTM D1525 or ISO 306, a density of 0.80 g/cm3 to 1.00 g/cm3 as measured by ASTM D792 or ISO 1183, and a melt flow index of 1.0-5.0 g/10 min (190° C./2.16 kg), as measured by ASTM D1238 or ISO 1133.
  11. 11 . The artificial turf fiber of claim 1 , wherein a weight percent ratio of the compatibilizer to the modifier polymer material is 2 to 30, or 5 to 20, or 7 to 30.
  12. 12 . The artificial turf fiber of claim 2 , wherein the thread-like structures have a diameter less than 50 micrometers, or less than 10 micrometers, or less than 1 micrometers.
  13. 13 . The artificial turf fiber of claim 2 , wherein the thread-like structures have a length of less than 2 mm.
  14. 14 . An artificial turf comprising an artificial turf backing, and an artificial turf fiber according to any of the previous claims incorporated into the artificial turf backing.
  15. 15 . A method of manufacturing an artificial turf fiber, the method comprising the steps of: creating a polymer mixture, the polymer mixture comprising 1.0 to 10.0 % by its weight a modifier polymer material, the remainder of the polymer mixture including a base polymer material and at least one additive, wherein the modifier polymer material is polyethylene selected from an ultra-low density polyethylene (ULDPE) or a low density polyethylene (LDPE) or a combination thereof, wherein the base polymer material is polyamide, or polyester, or a blend of the polyamide and the polyester, wherein the at least one additive includes a compatibilizer, wherein the polymer mixture comprises domains of the modifier polymer material; extruding the polymer mixture into a monofilament; quenching the monofilament; reheating the monofilament; and stretching the reheated monofilament to reshape the domains of the modifier polymer into threadlike structures and to form the monofilament into an artificial turf fiber;
  16. 16 . The method of claim 15 , wherein the compatibilizer comprises a polyethylene grafted with maleic anhydride or ethylene ethyl acrylate EEA or a combination thereof, wherein the modifier polymer material and the base polymer material are immiscible and the modifier polymer material domains are surrounded by a boundary layer of the compatibilizer and are within a continuous phase of the base polymer material; wherein the polymer domains comprise crystalline fractions and amorphous fractions, and wherein stretching the polymer domains into thread-like structures causes an increase in the size of the crystalline fractions relative to the amorphous fractions.
  17. 17 . The method of claim 15 , wherein the creating of the polymer mixture comprises the steps of: forming a first mixture by mixing the modifier polymer material with the compatibilizer; heating and extruding the first mixture; granulating the extruded first mixture; mixing and heating the granulated first mixture with the base polymer material to form the polymer mixture.
  18. 18 . A method for making artificial turf, the method comprising incorporating the artificial turf fiber of claim 1 into an artificial turf backing.

Description

FIELD OF THE INVENTION The invention relates generally to the field of artificial turf and, more particularly, to an artificial turf fiber that is especially suitable for outdoor sport and recreational venues in hot climates and a method for making the same. BACKGROUND Artificial turf fibers are often made entirely or predominantly from polyethylene (PE) due to its smoothness, elasticity, and relatively low cost compared to other polymers. However, in hot climate regions, artificial turf fibers made from polyamide (PA) are sometimes preferred because they are more resistant to environmental heat, as PA fibers generally have higher melting points than PE fibers. Typically, polyamides such as PA6 or PA6,6 (also known as Nylon 6 and Nylon 6,6) have melting points between 190° C. and 350° C., while PE has a melting point between 115° C. and 135° C. However, PA fibers tend to be more brittle and may feel less comfortable underfoot than PE fibers due to their greater toughness and stiffness. Additionally, PA fibers can retain more heat from sunlight, particularly in warmer climates, which may lead to discomfort for users. PA fibers may also absorb more moisture than PE fibers, resulting in longer drying times after rain or field irrigation. Artificial turf fibers made from polymer blends, such as PE and PA, have been discussed in the patent literature. For example, patent documents CN110777605A, JPH09268514A, CN117801413A, EP3122942 B1, and CN117801413A describe artificial turfs comprising mixtures of PA and PE polymers. Patent document KR102154131B1 describes a method for manufacturing artificial turf fibers with a marble color pattern by preparing a polymer mixture using polymers such as PA, polyethylene terephthalate, and polybutylene terephthalate, combined with a base polymer of PE or polyester (PET), with the base polymer comprising 70 to 90 wt % of the polymer mixture. For instance, CN117801413A describes the use of linear low-density polyethylene (LLDPE) in small amounts with PA, along with a compatibilizer of PE grafted with maleic anhydride (PE-g-MA). Additionally, JP H09268514A describes the use of high-density polyethylene (HDPE) in small amounts with PA and PE-g-MA as a compatibilizer. These patent documents generally describe using large amounts of PE in the polymer blend and/or combinations of specific polymer grades and compatibilizers that may result in artificial turf fibers that are too soft, insufficiently resistant to high temperatures, or prone to faster wear compared to pure PA or PE fibers. A common issue with artificial turf fibers made from PE and PA polymer blends is delamination, where the fibers separate at the interface between PE and PA polymers. This delamination can reduce the lifespan of artificial turf installations using such fibers. SUMMARY OF THE INVENTION Specifically, a three-phase polymer fiber, an artificial turf using said three-phase polymer fiber, and a method of manufacturing the three-phase artificial turf fiber and the artificial turf using said three-phase polymer fiber as specified in the independent claims. Embodiments are given in the dependent claims. Embodiments and examples disclosed herein can freely be combined with each other if they are not mutually exclusive. Embodiments of the invention may overcome or ameliorate at least some of the limitations of the prior art. Embodiments of the artificial turf fiber descried herein may exhibit an improved balance of heat resistance, wear resistance, resilience, softness, and other performance characteristics making it particularly suitable for applications such as sport fields, in particular outdoor sport fields, and recreational parks in hot climate regions of the world. According to embodiments, the artificial turf fiber mainly consists of polyamide (PA) and/or polyester (PET), and a small amount of ULDPE and/or LDPE, whereby the ULDPE and/or LDPE is comprised in the form of thread-like regions within a continuous PA or PET phase. The ULDPE and/or LDPE polymer which is used in a small amount may be referred to hereinafter as the modifier polymer. The PA polymer or the PET polymer which is used in a large amount may be referred to hereinafter as the base polymer. It has been discovered, rather unexpectedly, that combining a small amount of ULDPE (and/or LDPE) (the modifier polymer) with a large amount of PA or PET (the base polymer) and a suitable compatibilizer, then the ULDPE/LDPE forms thread-like structures surrounded by the compatibilizer within a PA or a PET continuous phase. The ULDPE/LDPE thread-like structures provide PA or PET based fibers with an improved balance of heat resistance, resilience and softness compared to existing grades. The fibers are less brittle, free of delamination, and markedly more robust and wear resistant in hot climates than fibers made from PA alone or mixtures of PA with linear low density polyethylene (LLDPE) or with high density polyethylene (HDPE). The bonding of the ULDPE/LD