Artificial turf and production method

Abstract

The present invention provides a method for producing an artificial turf (1000). The method comprises the steps of creating a polymer mixture, such as a polymer mixture (400), where the polymer mixture is at least a three-phase system. The polymer mixture comprises a first polymer, a second polymer, and a compatibilizer. The first polymer is polyamide (PA) and the second polymer is polyethylene (PE). The first polymer is present in an amount of 0.125 weight percent to 5 weight percent, the second polymer is present in an amount of 60 weight percent to 97 weight percent, and the compatibilizer is present in an amount of 0.375 weight percent to 15 weight percent. The first polymer and the second polymer are immiscible, and the first polymer forms polymer beads surrounded by the compatibilizer within the second polymer.

Description

[Technical field]

[0001] The present invention relates to the production of artificial grass and artificial turf, also called synthetic grass. The present invention further relates to the production of fibers that mimic grass, and in particular to the product and production method of artificial grass fibers based on polymer blends, and to artificial grass carpets made from these artificial grass fibers. [Background technology]

[0002] Artificial turf or synthetic grass is a surface composed of fibers used to replace grass. The structure of the artificial turf is designed so that the artificial turf has a similar appearance to grass. Typically, artificial turf is used as a surface for sports, stadiums, or playgrounds, such as soccer, American football, rugby, tennis, golf, etc. Additionally, artificial turf is frequently used in landscaping applications.

[0003] The advantage of using artificial turf is that it eliminates the need to care for the grass playing or landscaping surface, such as regular mowing, digging, fertilizing, and watering. Watering may be difficult, for example, due to local restrictions on water use. In other climate zones, grass regrowth and reformation of closed grass cover is slower compared to damage to natural grass surfaces caused by playing and / or exercising on the ground. Although artificial turf grounds do not require the same care and effort to maintain, they may require some maintenance, such as dirt and debris must be cleaned and brushed periodically. This may be done to help the fibers stand up after being stepped on during playing or exercising. It may be beneficial if an artificial turf playing field can withstand high mechanical wear and tear, resist UV, withstand thermal cycling or thermal aging, and resist interaction with chemicals and various environmental conditions throughout a normal use period of 5 to 15 years. It is therefore beneficial if the artificial turf has a long service life, is durable, and maintains its playing and surface properties and appearance throughout its use period.

[0004] US patent application US2010 / 0173102 A1 discloses an artificial turf characterized in that the material for the cladding has a hydrophilicity different from the hydrophilicity of the material used for the core. Summary of the Invention

[0005] The invention provides in the independent claims a method for producing an artificial lawn. Embodiments are given in the dependent claims.

[0006] In one aspect, the present invention provides a method for manufacturing an artificial grass carpet. The method includes the step of creating a polymer mixture. A polymer mixture as used herein includes a mixture of different types of polymers, and in some cases includes a polymer mixture to which various additives have been added. The term "polymer mixture" may also be replaced with the term "master batch" or "compound batch". The polymer mixture is at least a three-phase system. A three-phase system as used herein includes a mixture that is separated into at least three distinct phases. The polymer mixture includes a first polymer, a second polymer, and a compatibilizer. These three items form the phases of a three-phase system. If there is an additional polymer or compatibilizer added to the system, the three-phase system may increase to a system of four, five, or more phases. The first polymer and the second polymer are immiscible. The first polymer forms polymer beads surrounded by the compatibilizer within the second polymer.

[0007] The method further comprises the step of extruding the polymer mixture into a monofilament. To effect this extrusion, the polymer mixture may, for example, be heated. The method further comprises the step of quenching the monofilament. During this step, the monofilament is cooled. The method further comprises the step of reheating the monofilament. The method further comprises the step of stretching the reheated filament to transform the polymer beads into thread-like regions and form the monofilament into an artificial turf fiber. During this step, the monofilament is stretched. This makes the monofilament longer, and in this process the polymer beads are stretched and elongated. Depending on the amount of stretching, the polymer beads become more elongated.

[0008] In this specification, the "thread region" is also referred to as the "fiber region."

[0009] The method further comprises incorporating the artificial turf fibers into an artificial turf substrate. In some examples, the artificial turf substrate is a fabric or a fabric mat.

[0010] The incorporation of the artificial grass fibers into the artificial grass substrate can be performed, for example, by tufting the artificial grass fibers into the artificial grass substrate and tying the tufted artificial grass fibers to the artificial grass substrate. For example, the artificial grass fibers can be inserted into the substrate using needles and tufted in the manner in which carpet can be tufted. If loops of artificial grass fibers are formed, the loops can be cut during the same step. The method further includes a step of tying the artificial grass fibers to the artificial grass substrate. In this step, the artificial grass fibers are tied or attached to the artificial grass substrate. This can be performed in various ways, such as gluing or coating the surface of the artificial grass substrate to hold the artificial grass fibers in place. This can be performed, for example, by coating the surface or a portion of the artificial grass substrate with a material such as latex or polyurethane.

[0011] The incorporation of the artificial grass fibers into the artificial grass substrate can alternatively be carried out, for example, by weaving the artificial grass fibers into the artificial grass substrate (or fiber mat) during the manufacture of the artificial grass carpet. This technique for producing artificial grass is known from US patent application US20120125474 A1.

[0012] The term "polymer bead" or "bead" may refer to a localized region, such as a droplet, of a polymer that is immiscible in a second polymer. The polymer beads may be round or spherical or ovoid in some instances, but they may also be irregularly shaped. In some instances, the polymer beads typically have a size of about 0.1 to 3 micrometers, preferably 1 to 2 micrometers, in diameter. In other instances, the polymer beads are larger. They may have a size, for example, with a diameter of up to 50 micrometers.

[0013] In some instances, the drawn monofilaments may be used directly as artificial turf fibers. For example, the monofilaments may be extruded as tapes or other shapes.

[0014] In other instances, the artificial turf fibers may be bundles or groups of several drawn monofilament fibers that are generally cabled, twisted, or tied together. In some cases, the bundles are rewound with so-called rewinding yarns, which hold the bundle of yarns together and prepare it for a subsequent tufting or weaving process.

[0015] The size of the monofilament may be, for example, 50 to 600 micrometers in diameter. The yarn weight can usually reach 50 to 3000 dtex.

[0016] The embodiment may have the advantage that the second polymer and any immiscible polymer cannot peel off from each other. The thread-like regions are embedded in the second polymer. Therefore, they cannot peel off. The use of the first and second polymers allows the properties of the artificial grass fiber to be tailored. For example, a softer plastic can be used for the second polymer to give the artificial grass a softer feel, more like natural grass. A stiffer plastic can be used for the first polymer or other immiscible polymer to give the artificial grass a higher resilience and stability, and the ability to bounce back after being stepped on or pressed down.

[0017] A further advantage may be that in some cases the thread-like regions are concentrated in the central region of the monofilament during the extrusion process, which concentrates the stiffer material in the center of the monofilament and a greater amount of the softer plastic in the outer surface or outer region of the monofilament, which may result in an artificial turf fiber with more grass-like properties.

[0018] A further advantage may be that the artificial grass fibers have improved long term resilience, which may reduce the maintenance needs of the artificial grass and reduce the need to brush the fibers as they will more naturally regain their shape and stand up after use or being stepped on.

[0019] In another embodiment, the polymer beads include crystalline and amorphous portions. The polymer mixture is likely to be heated during the extrusion process, and a portion of the first polymer and a portion of the second polymer may also have more amorphous or more crystalline structures in various regions. By stretching the polymer beads into thread-like regions, the size of the crystalline portion relative to the amorphous portion in the first polymer may be enlarged. For example, this may make the first polymer stiffer than when it has an amorphous structure. This may result in an artificial turf with higher stiffness and the ability to bounce back when pressed down. Also, in some cases, stretching the monofilament may make a larger portion of the structure of the second polymer or other additional polymer more crystalline.

[0020] In a specific example of this, the first polymer may be a polyamide and the second polymer may be a polyethylene. Stretching the polyamide increases the crystalline regions making it harder. This is also true for other plastic polymers.

[0021] In another embodiment, the step of forming the polymer mixture comprises mixing the first polymer with the compatibilizer to form a first mixture. The step of forming the polymer mixture further comprises heating the first mixture. The step of forming the polymer mixture further comprises extruding the first mixture. The step of forming the polymer mixture further comprises extruding the first mixture. The step of forming the polymer mixture further comprises granulating the extruded first mixture. The step of forming the polymer mixture further comprises mixing the granulated first mixture with the second polymer. The step of forming the polymer mixture further comprises heating the granulated first mixture with the second polymer to form the polymer mixture. This particular method of forming a polymer mixture can be advantageous because it allows for very precise control over how the first polymer and the compatibilizer are dispersed within the second polymer. For example, the size or shape of the extruded first mixture can determine the size of the polymer beads within the polymer mixture.

[0022] In the above-mentioned method of making the polymer mixture, for example, the so-called single screw extrusion method can be used. As an alternative to this, the polymer mixture can also be made by combining all of its constituent components at once. For example, the first polymer, the second polymer, and the compatibilizer can all be added together at the same time. Other raw materials such as additional polymers or other additives can also be combined at the same time. The amount of mixing of the polymer mixture can then be increased, for example, by using a twin screw feed for extrusion. In this case, the desired dispersion of the polymer beads can be achieved by using the appropriate mixing ratio or amount.

[0023] In another embodiment, the polymer mixture is at least a four-phase system. The polymer mixture comprises at least a third polymer. The third polymer is immiscible with the second polymer. The third polymer further forms polymer beads within the second polymer surrounded by the compatibilizer.

[0024] In another embodiment, the step of preparing the polymer mixture comprises mixing a first polymer and a third polymer with a compatibilizer to form a first mixture. The step of preparing the polymer mixture further comprises heating the first mixture. The step of preparing the polymer mixture further comprises extruding the first mixture. The step of preparing the polymer mixture further comprises granulating the extruded first mixture. The step of preparing the polymer mixture further comprises mixing the first mixture with the second polymer. The step of preparing the polymer mixture further comprises heating the first mixture with the second polymer to form the polymer mixture. This method may provide a precise means of preparing the polymer mixture and controlling the size and distribution of the polymer beads using two different polymers. Alternatively, the first polymer may be used to prepare a granule with a compatibilizer separately from preparing the third polymer with the same or different compatibilizer. The granule may then be mixed with the second polymer to prepare the polymer mixture.

[0025] As an alternative to this, the polymer blend may be made by adding the first polymer, the second polymer, the third polymer, and the compatibilizer all together at the same time and then mixing them more vigorously, for example, a twin screw feed may be used in the extruder.

[0026] In another embodiment, the third polymer is a polar polymer.

[0027] In another embodiment, the third polymer is a polyamide.

[0028] In another embodiment, the third polymer is polyethylene terephthalate, also commonly abbreviated as PET.

[0029] In another embodiment, the third polymer is polybutylene terephthalate, also commonly abbreviated as PBT.

[0030] In another embodiment, the polymer blend comprises between 1% and 30% by weight of the combined first and third polymers, in this example the remainder of the weight may be made up by components such as the second polymer, the compatibilizer, and any other additional additives placed in the polymer blend.

[0031] In another embodiment, the polymer blend comprises between 1 and 20 weight percent of the combined first and third polymers. Again, in this example, the remainder of the weight of the polymer blend may be made up of the second polymer, the compatibilizer, and any other additional additives.

[0032] In another embodiment, the polymer blend comprises between 5% and 10% by weight of the combined first and third polymers. Again, in this example, the remainder of the weight of the polymer blend may be made up of the second polymer, the compatibilizer, and any other additional additives.

[0033] In another embodiment, the polymer mixture comprises between 1% and 30% by weight of the first polymer, in this example, the remainder of the weight may be made up, for example, by the second polymer, the compatibilizer, and any other additional additives.

[0034] In another embodiment, the polymer blend comprises between 1% and 20% by weight of the first polymer, in this example, the remainder of the weight may be made up of the second polymer, the compatibilizer, and any other additional additives mixed into the polymer blend.

[0035] In another embodiment, the polymer blend comprises between 5% and 10% by weight of the first polymer, this example may have the remainder of the weight made up by the second polymer, the compatibilizer, and any other additional additives blended into the polymer blend.

[0036] In another embodiment, the first polymer is a polar polymer.

[0037] In another embodiment, the first polymer is a polyamide.

[0038] In another embodiment, the first polymer is polyethylene terephthalate, commonly known by the abbreviation PET.

[0039] In another embodiment, the first polymer is polybutylene terephthalate, also known by the common abbreviation PBT.

[0040] In another embodiment, the second polymer is a non-polar polymer.

[0041] In another embodiment, the second polymer is polyethylene.

[0042] In another embodiment, the second polymer is polypropylene.

[0043] In another embodiment, the second polymer is a mixture of the polymers previously described that can be used for the second polymer.

[0044] In another embodiment, the compatibilizer is any one of the following: maleic acid grafted onto polyethylene or polyamide; maleic anhydride grafted onto free radical initiated graft copolymers of polyethylene, SEBS, EVA, EPD, or polypropylene with unsaturated acids or anhydrides such as maleic acid, glycidyl methacrylate, maleic acid ricinol oxazoline, etc.; graft copolymers of SEBS with glycidyl methacrylate, graft copolymers of EVA with mercaptoacetic acid and maleic anhydride; graft copolymers of EPDM with maleic anhydride; graft copolymers of polypropylene with maleic anhydride; polyolefin graft polyamide polyethylene or polyamide; polyacrylic acid type compatibilizers, or ethylene ethyl acrylate copolymer (EEA), also called ethylene ethyl acrylate.

[0045] According to a preferred embodiment, the compatibilizer is maleic acid grafted to polyethylene, or ethylene ethyl acrylate (EEA).

[0046] According to some embodiments, between 0.5 and 1 weight percent of the polymer mixture can consist of EEA.

[0047] For example, the EEA used as a compatibilizer may have a comonomer content (by weight) of 15% to 25% ethyl acrylate (EA), especially 18% to 23% EA.

[0048] According to a preferred embodiment, the EEA has a density of about 0.90 g / cm3 to 1.0 g / cm3, for example 0.90 g / cm3 to 0.96 g / cm3 (ASTM D792). Preferably, the EEA used as a compatibilizer has a melt flow index ((g / 10 min @ 190°C / 2.16 kg) (ASTM D1238)) of 20 to 22, in particular 20.5 to 21.5.

[0049] In one embodiment, the compatibilizer is maleic anhydride grafted polyethylene (also called maleic anhydride grafted polyethylene).

[0050] According to some embodiments, between 0.5 and 1 weight percent of the polymer blend may consist of maleic anhydride grafted polyethylene.

[0051] In a preferred embodiment, the maleic anhydride grafted polyethylene has a viscosity of 0.83 to 1.03 g / cm as measured by the displacement method (i.e., ASTM D792, ISO 1183 test method). 3 Density of preferably 0.93 g / cm 3 and / or a melt flow index measured at 190° C. / 2.16 kg (i.e., ASTM D1238, ISO 1133 test method) of 1.575 g / 10 min to 1.925 g / 10 min, preferably 1.75 g / 10 min.

[0052] In one embodiment, the first polymer is present in an amount of 0.1 to 30 weight percent of the second polymer. In another embodiment, the first polymer is present in an amount less than or equal to 10 weight percent of the second polymer, preferably in an amount of 0.4 to 10 weight percent of the second polymer, and more preferably in an amount of 0.5 weight percent of the second polymer. In yet another embodiment, the first polymer is present in an amount of 0.1 to 5 weight percent of the second polymer, preferably in an amount of 0.4 to 5 weight percent of the second polymer, and more preferably in an amount of 0.4 to 1 weight percent of the second polymer.

[0053] In another embodiment, the polymer blend comprises 80-90% by weight of the second polymer, in this example the balance of the weight may be made up of the first polymer, optionally the second polymer if a second polymer is present in the polymer blend, the compatibilizer, and any other chemicals or additives added to the polymer blend.

[0054] In another embodiment, the polymer mixture further comprises any one of waxes, matting agents, UV stabilizers, flame retardants, antioxidants, pigments, and combinations thereof. These listed additional ingredients can be added to the polymer mixture to provide other desired properties to the artificial grass fibers, such as flame retardancy, a green color so that the artificial grass more closely resembles grass, and better stability in the sun.

[0055] In another embodiment, creating the artificial turf fiber includes weaving monofilaments into the artificial turf fiber, i.e., in some instances, the artificial turf fiber is not a single monofilament, but rather a combination of many fibers.

[0056] In another embodiment, the artificial turf fibers are yarns.

[0057] In another embodiment, the method further comprises bundling the stretched monofilaments together to create artificial turf fibers.

[0058] In another embodiment, the method further comprises braiding, knotting, or spinning a plurality of monofilaments together to create the artificial turf fiber. A plurality of monofilaments, for example 4 to 8, can be formed or finished into a yarn.

[0059] In another aspect, the present invention provides the production of artificial turf by any one of the aforementioned methods.

[0060] In another aspect, the present invention provides an artificial turf comprising an artificial turf substrate and artificial turf fibers tufted onto the artificial turf substrate. The artificial turf substrate can be, for example, a fabric or other flat structure to which fibers can be tufted. The artificial turf fiber has at least one monofilament. Each of the at least one monofilament includes a first polymer in the form of a thread-like region. Each of the at least one monofilament includes a second polymer, and the thread-like region is embedded in the second polymer. Each of the at least one monofilament includes a compatibilizer that surrounds each of the thread-like regions and separates the at least one first polymer from the second polymer. This artificial turf can have the advantage of being extremely durable because the thread-like regions are embedded in the second polymer via the compatibilizer. Thus, they cannot be peeled off. The second polymer surrounds the first polymer, providing a firm artificial turf that is soft and feels similar to real grass. The artificial turf described herein is different from artificial turf that is co-extruded. In co-extrusion, a core, typically 50 to 60 micrometers in diameter, may be surrounded by an outer cover or exterior material having a diameter of about 200 to 300 micrometers. In this artificial turf, there are multiple thread-like regions of the first polymer. The thread-like regions may not extend along the entire length of the monofilament. The artificial turf may also have properties or characteristics provided by any of the steps of the method described above.

[0061] In another embodiment, the thread-like region has a diameter less than 20 micrometers.

[0062] In another embodiment, the thread-like region has a diameter less than 10 micrometers.

[0063] In another embodiment, the thread-like region has a diameter between 1 and 3 micrometers.

[0064] In another embodiment, the artificial turf fibers extend a predetermined length beyond the artificial turf substrate, and the thread-like regions have a length that is less than half of the predetermined length.

[0065] In another embodiment, the thread-like region has a length of less than 2 mm.

[0066] According to another embodiment of the present disclosure, which may be combined with one or more of the embodiments described above, a method for producing an artificial turf comprises the steps of preparing a polymer mixture, where the polymer mixture is at least a three-phase system. The polymer mixture comprises a first polymer, a second polymer, and a compatibilizer. The first polymer is polyamide (PA) and the second polymer is polyethylene (PE). The first polymer is included in an amount of 0.125 weight percent to 5 weight percent, the second polymer is included in an amount of 60 weight percent to 97 weight percent, and the compatibilizer is included in an amount of 0.375 weight percent to 15 weight percent. The first polymer and the second polymer are immiscible, and the first polymer forms polymer beads surrounded by the compatibilizer within the second polymer.

[0067] In a preferred embodiment, the polyamide is nylon (e.g., nylon 6). However, the scope of the present disclosure includes other polyamides, including both naturally and synthetically occurring polyamides. For example, polyamides of the present disclosure can include naturally occurring polyamides (i.e., proteins), such as wool and silk, and synthetically created polyamides, such as aramid and sodium poly(aspartate).

[0068] In another preferred embodiment, the second polymer is a polyethylene, such as a polyethylene resin produced by DOW®. However, the scope of the present disclosure encompasses other polyethylenes, such as biopolyethylenes (i.e., polyethylenes produced / provided from renewable resources rather than fossil fuels). For example, the scope of the present disclosure includes polyethylenes produced from sugar cane, where high and low density polyethylenes are produced from bioethanol derived from sugar cane. Embodiments of the present disclosure also contemplate polyethylenes made from other feedstocks, such as wheat grain and sugar beets.

[0069] Increasing the content of the compatibilizer in the PA / PE polymer mixture, preferably comprising a first polymer present in an amount of 0.125 to 5 weight percent, a second polymer present in an amount of 60 to 97 weight percent, and a compatibilizer present in an amount of 0.375 to 15 weight percent, has the technical effect of changing the flow characteristics of the mixture to make the mass of the mixture more uniform, thereby making the pressure and temperature of the mixture more uniform during processing of the mixture, avoiding fluctuations in energy consumption, and preventing the mixture from separating during and after extrusion from a nozzle plate or die. The compatibilizer and the first polymer (e.g., polyamide) may be present in the formulation in a defined ratio of about 5 parts to 1 part (5:1 part) to about 2:1 part, more preferably in a defined ratio of about 4:1 to 2.5:1, and even more preferably in a defined ratio of about 3:1.

[0070] According to one embodiment, the compatibilizer preferably comprises ethylene ethyl acrylate (i.e., a copolymer consisting of a basic resin produced by catalytic copolymerization of ethylene and ethyl acrylate). According to another embodiment, the compatibilizer comprises maleic anhydride. The polymer mixture embodiments of the present disclosure have the technical effect of faster separation at the nozzle plate and / or die (i.e., faster separation when extruding the mixture from the nozzle plate and / or die), or in other words, provide a more efficient and more uniform extrusion stage that produces monofilaments with less wasted material, and can also provide the technical effect of artificial turf fibers having greater polarity, better abrasion resistance, better elongation at break, better recovery and tensile strength, better suitability for incorporation into artificial turf substrates, and / or better suitability as field hockey yarns. Additionally, the polymer mixtures of the present invention including ethylene ethyl acrylate compatibilizers also have the technical effect of optimizing the service life of artificial turf fiber making machines, particularly extending the service life and / or use of extrusion machines and / or components such as nozzle plates and / or dies, and extending the time between cleaning (e.g. ultrasonic cleaning) of such components. For example, embodiments of the disclosed polymer mixtures extend the time between cleaning of nozzles and / or dies from 2-3 days when an anhydride compatibilizer is used to 2-3 weeks when an ethylene ethyl acrylate compatibilizer is used.

[0071] In another embodiment, the step of preparing the polymer mixture comprises the steps of forming a first mixture by mixing the first polymer with the compatibilizer, heating the first mixture, extruding the first mixture, granulating the extruded first mixture, mixing the granulated first mixture with the second polymer, and heating the granulated first mixture with the second polymer to form the polymer mixture.

[0072] In another embodiment, the method may further include extruding the polymer mixture into a monofilament, quenching the monofilament, reheating the monofilament, stretching the reheated monofilament to transform the polymer beads into a fiber region and forming the monofilament into an artificial turf fiber. The fiber region includes the first polymer and is at least partially surrounded by the compatibilizer and separated from the second polymer by the compatibilizer. The fiber region is centrally located, so that the fiber region does not peel off after formation. The method may also further include incorporating the artificial turf fiber into an artificial turf substrate.

[0073] In yet another embodiment, the polyethylene of the second polymer comprises at least a first linear low density polyethylene (LLDPE) and a second LLDPE, the first LLDPE having a melt flow rate of about 0.9 g / 10 min to about 1.1 g / 10 min as measured according to DIN EN ISO 1133 190° C. / 2.16 kg, and the second LLDPE having a melt flow rate of about 2.2 g / 10 min to about 2.4 g / 10 min as measured according to DIN EN ISO 1133 190° C. / 2.16 kg. Suitable exemplary embodiments of LLDPE are manufactured by DOW®.

[0074] In one embodiment, the first LLDPE and the second LLDPE each have a viscosity of about 0.90 g / cm 3 to about 0.93 g / cm 3 , preferably about 0.91 g / cm 3 to about 0.925 g / cm 3 According to one embodiment, the first LLDPE has a density of 0.917 g / cm 3 and the second LLDPE has a density of 0.922 g / cm 3 has a density of

[0075] In another embodiment, the first and second LLDPEs are preferably present in the formulation in a defined ratio of about 1 part to 20 parts (1:20 parts) to about 1:2 parts, more preferably about 1:20 to 1:3. The preferred ratio has the technical effect of reducing the separation of the PA, which is important for imparting the final product with adequate wear resistance. The preferred ratio ensures that the melt flow index (MFI) of the formulation (i.e., the mixture) approaches an optimal MFI, which in one embodiment corresponds to the MFI of the second LLDPE. Separation is particularly relevant when pressure drops occur at the extrusion nozzle plate and / or die.

[0076] In one embodiment, the weight ratio of the first LLDPE and the second LLDPE is between 1:20 and 1:3 and the melt flow rate of the blend of the first LLDPE and the second LLDPE is from about 1.95 g / 10 min to about 2.25 g / 10 min, measured according to DIN EN ISO 1133 190° C. / 2.16 kg.

[0077] According to another embodiment, the polyethylene of the second polymer further comprises high density polyethylene (HDPE), the HDPE having a melt flow rate of about 3.9 g / 10 min to about 4.1 g / 10 min as measured according to DIN EN ISO 1133 190° C. / 2.16 kg, and the HDPE is present in an amount of 0.1 weight percent to 15 weight percent. In yet another embodiment, the HDPE has a melt flow rate of about 0.93 g / cm 3 to about 0.97 g / cm 3 , preferably about 0.95 g / cm 3 to about 0.96 g / cm 3 has a density of

[0078] In one embodiment, the polymer mixture further comprises a processing aid additive. The processing aid additive has the technical effect of reducing the viscosity of the polymer mixture (also called the processing mixture melt) during processing to reduce or prevent deposits from accumulating on extruder components such as the extruder screw, extruder housing, and nozzle and / or die plate. The processing aid additive may comprise a fluoropolymer-based processing additive, a siloxane, or a combination thereof. The processing aid additive may be included in an amount of 0.1 weight percent to 1.0 weight percent.

[0079] Conventional processing aid additives, such as products by BYK-Altana and 3M (e.g., Dynamar®), contain long-chain polyfluoropolymers, such as long-chain polyfluoroalkyl compounds. Although there are currently environmental concerns about the use of short-chain polyfluoropolymers (e.g., short-chain polyfluoroalkyl substances (PFAS)), it is difficult to distinguish analytically between long-chain polyfluoropolymers and short-chain polyfluoropolymers, and as a result, artificial turf fibers are only tested for the presence of fluorine. When the presence of fluorine is detected, regulatory agencies usually conclude that short-chain PFAS is likely to be present at least as an impurity. Therefore, one advantage of using only siloxanes as processing aid additives is that, in addition to obtaining fluorine-free formulations and fluorine-free products, it also eliminates any doubt about whether the formulations and products contain short-chain polyfluoropolymers, thereby reducing any concerns that the products are harmful to the environment.

[0080] In a preferred embodiment, the processing aid additive of the present disclosure is a siloxane. In another embodiment, the siloxane is included in the polymer mixture in an amount of 0.5 wt% to result in a fluorine-free mixture and fiber product. In addition to addressing environmental / toxicological concerns, the use of siloxane as a processing aid additive can also reduce deposits that may occur during processing of PA / PE blends (i.e., mixtures). As described above, compatibilizers can reduce deposits, but deposits can still accumulate on processing machinery components, such as those associated with the extrusion process. Using only siloxane formulations has the technical effect of extending die and / or nozzle life from about 24 hours to up to 72 hours.

[0081] In yet another embodiment, the polymer blend may further include a polymeric protection blend having at least one of a hindered amine light stabilizer, an antioxidant, an oxygen scavenger, a third LLDPE, and / or a filler and a pigment. The polymeric protection blend may be included in an amount of 3.0 weight percent to 15.0 weight percent. In one embodiment, the protection blend may be included in about 10 weight percent of the polymer blend, and the protection blend itself may include: (1) 14 weight percent of the hindered amine light stabilizer, antioxidant, and oxygen scavenger; (2) 45-65 weight percent of the third LLDPE (e.g., a polymeric carrier); and (3) 31-41 weight percent of the filler and pigment.

[0082] In another embodiment, the polymer blend comprises 0.125 to 5 weight percent of the first polymer, 0.375 to 15 weight percent of a compatibilizer, 3 to 15 weight percent of a polymeric protection blend including at least one of a hindered amine light stabilizer, an antioxidant, an oxygen scavenger, a third LLDPE, a filler, and a pigment, and 0.1 to 1.0 weight percent of a processing aid additive, the processing aid additive being a fluoropolymer-based processing additive, a siloxane, or a combination thereof. The second polymer comprises 20 to 75 weight percent of a first linear low density polyethylene (LLDPE), the first LLDPE having a melt flow rate of about 0.9 g / 10 min to about 1.1 g / 10 min as measured according to DIN EN ISO 1133 at 190° C. / 2.16 kg, 5 to 25 weight percent of a second LLDPE, the second LLDPE having a melt flow rate of about 2.2 g / 10 min to about 2.4 g / 10 min as measured according to DIN EN ISO 1133 at 190° C. / 2.16 kg, and 0.01 to 15 weight percent of a high density polyethylene (HDPE), the HDPE having a melt flow rate of about 3.9 g / 10 min to about 4.1 g / 10 min as measured according to DIN EN ISO 1133 at 190° C. / 2.16 kg.

[0083] According to yet another embodiment, the polymer blend comprises 0.25 to 2.5 weight percent of a first polymer, 0.75 to 7.5 weight percent of a compatibilizer, 4 to 11 weight percent of a polymeric protection blend including at least one of a hindered amine light stabilizer, an antioxidant, an oxygen scavenger, a third LLDPE, a filler, and a pigment, and 0.15 to 0.75 weight percent of a processing aid additive, where the processing aid additive is a fluoropolymer-based processing additive, a siloxane, or a combination thereof. The second polymer comprises 55 to 70 weight percent of a first linear low density polyethylene (LLDPE), the first LLDPE having a melt flow rate of about 0.9 g / 10 min to about 1.1 g / 10 min as measured according to DIN EN ISO 1133 190° C. / 2.16 kg, 10 to 20 weight percent of a second LLDPE, the second LLDPE having a melt flow rate of about 2.2 g / 10 min to about 2.4 g / 10 min as measured according to DIN EN ISO 1133 190° C. / 2.16 kg, and 8 to 14 weight percent of a high density polyethylene (HDPE), the HDPE having a melt flow rate of about 3.9 g / 10 min to about 4.1 g / 10 min as measured according to DIN EN ISO 1133 190° C. / 2.16 kg.

[0084] In one embodiment, the polymer beads include crystalline and amorphous portions, and stretching the polymer beads into fibrous (ie, thread-like) regions increases the size of the crystalline portions relative to the amorphous portions.

[0085] According to one embodiment of the present disclosure, the monofilament includes a circular bulge that includes a core (e.g., a cylindrical core) and two lobes extending from the circular bulge. In another embodiment, the step of extruding the polymer mixture into a monofilament includes co-extruding the polymer mixture with a liquid cladding polymer component. Upon co-extrusion, the polymer mixture forms a cylindrical core and the liquid cladding polymer component forms a cladding surrounding the core.

[0086] In one embodiment, the cladding has a non-circular profile. The scope of the present disclosure includes opposed and / or non-opposed protrusions of the cladding. In one embodiment, the profile of at least one of the protrusions includes a concave side. However, the scope of the present disclosure includes protrusions or portions of protrusions having a profile with a non-concave side (e.g., a convex side or a straight side).

[0087] In general, the core / cladding structure may have the advantage that the core can be optimized to provide a desired degree of elasticity or stiffness of each blade of artificial turf as a whole, while the cladding can be designed to provide specific surface properties, such as softness and appearance. In particular, the core may include a core polymer and / or thread polymer that provides the artificial turf fibers with sufficient stiffness so that the desired restoring force of the artificial turf blades produced from these artificial turf fibers is achieved. In the specific case where a soft cladding polymer is selected and the core polymer is the same polymer as the cladding polymer, the restoring force of the artificial turf fiber comes only from the thread-like region, and the thread polymer should be selected accordingly.

[0088] The miscibility of the core and cladding polymers may obviate the need for additional interface materials to provide a sufficient amount of intimacy between the core and cladding. During fabrication from a fluid state, the core and cladding polymers can mix together to form a quasi-integral transition zone between the core and cladding that provides mechanical stability comparable to that of a single component fiber.

[0089] When an appropriate non-circular geometry is selected, the non-circular profile of the cladding can increase the surface area to mass ratio of each artificial grass fiber compared to a simple circular cylindrical fiber. Thus, artificial grass produced from these artificial grass fibers can feature improved coverage per unit area that would otherwise be achieved by producing artificial grass with a higher leaf density. According to embodiments of the present invention, improved coverage can be achieved with less polymer consumption, thereby reducing production costs.

[0090] According to another embodiment of the present disclosure, the monofilament includes a circular bulge and two lobes extending from the circular bulge. In one embodiment, the monofilament shape including the circular bulge and the two lobes is formed upon extrusion of the mixture through a nozzle plate or die.

[0091] Each monofilament may be a cylindrical polymer fiber, where the term "cylindrical" refers to a generally right circular cylinder, i.e., a cylinder whose primary axis is oriented perpendicular to its reference plane or cross-section. Specifically, each fiber produced may be a non-circular cylinder, i.e., have a non-circular cross-section. Examples of non-circular cross-sections include ellipses or polygons. It should be understood that the cross-sections of the core and cladding may be selected independently of each other, and that each of the core and cladding may have a non-circular cross-section. In a non-limiting example, an elliptical core is surrounded by a bean-shaped cladding. In another non-limiting example, the fiber has a circular core and a cladding with two protrusions extending outward from the core for a length of at least the diameter of the core.

[0092] According to an embodiment, the profile of at least one of the protrusions comprises a wavy section over at least 60% of one side of said at least one protrusion. A wavy section is understood here as a part of the fiber profile that contains repetitive elements that are small compared to the overall dimensions of the fiber. In the scope of the present disclosure, this is considered to be the case if at least two instances (i.e. one repetition) of a repetitive element are contained in each of the at least one wavy protrusion and if, for each of the at least one wavy protrusion, its amplitude is not greater than 25 percent of the maximum thickness of said protrusion.

[0093] The corrugations can further increase the surface area to mass ratio and thus contribute to the benefits mentioned above. Another beneficial effect can be that the diffuse light scattering of artificial grass produced from artificial grass fibers with a wavy profile is increased compared to fibers with a smooth surface. In addition, the corrugations can increase the resilience of the fibers. The corrugations can also reduce the adhesion of liquids (e.g. rainwater) to the fibers by providing a guide edge for the droplets, i.e. the corrugations can increase the fiber surface while reducing the liquid contact surface. Thus, artificial grass produced from artificial grass fibers with a wavy profile can be produced more efficiently and have a shorter drying time during use.

[0094] According to an embodiment, the wavy section spans one side of the non-circular profile, and the non-circular profile does not include any further wavy section other than the wavy side. In one example, the fiber is bilateral and includes one smooth surface (the smooth side of the profile, e.g., straight or concave) and one grooved surface (the wavy side). In addition to the aforementioned general advantages of the wavy section, the one-sided wavy section may more closely resemble the leaf structure found in natural grass, which may beneficially contribute to the properties of the artificial grass produced with such fibers. In such an artificial grass, a portion of the grooved surface of each fiber may appear on the grass surface in a stochastic distribution. This can give the grass a less homogeneous and less matte appearance. In addition, the use of such grass for example in sports activities can locally give the artificial grass blade a defined orientation, so that the oriented contact area is easily distinguishable from its stochastically oriented environment.

[0095] In a further aspect, the present invention relates to an artificial turf comprising an artificial turf substrate; and an artificial turf yarn comprising a plurality of fibers, each of the plurality of fibers comprising a polyamide fiber region substantially surrounded by a compatibilizer comprising ethylene ethyl acrylate and polyethylene, the compatibilizer being located between the polyamide and the polyethylene such that the fiber regions are centrally located and do not delaminate.

[0096] It will be understood that one or more of the above-mentioned embodiments of the present invention may be combined, unless the combined embodiments are mutually exclusive. [Brief description of the drawings]

[0097] In the following, by way of example only, embodiments of the invention are explained in more detail with reference to the drawings, in which:

[0098] [Figure 1] 1 shows a flow chart illustrating an example of a method for producing artificial turf. [Diagram 2] 1 shows a flow chart illustrating one method of making a polymer mixture. [Diagram 3] 1 shows a flow chart illustrating a further example of how to make a polymer mixture. [Figure 4] FIG. 1 shows a diagram illustrating a cross section of a polymer mixture. [Diagram 5] Further examples of polymer mixtures are given below. [Figure 6] 1 illustrates the extrusion of a polymer mixture into a monofilament. [Figure 7] A cross section of a small segment of the monofilament is shown. [Figure 8] 1 illustrates the effect of stretching a monofilament. [Figure 9] 1 shows an electron microscope image of a cross section of a drawn monofilament. [Figure 10] 1 shows an example of a cross section of an example of artificial turf. [Figure 11] 1 shows a radial cross-section of a monofilament for producing artificial grass fibers according to one embodiment of the present disclosure. [Figure 12] 1 shows a radial cross-section of a monofilament for producing artificial grass fibers according to another embodiment of the present disclosure. [Figure 13] 1 illustrates a cross-sectional profile of a wavy artificial grass fiber according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0099] Similarly numbered elements in these figures are equivalent elements or perform the same function. An element described earlier is not necessarily described in a later figure if the function is equivalent.

[0100] FIG. 1 shows a flow chart illustrating an example of a method for producing an artificial turf. First, in step 100, a polymer mixture is made. The polymer mixture is at least a three-phase system. The polymer mixture comprises a first polymer. The polymer mixture further comprises a second polymer and a compatibilizer. The first polymer and the second polymer are immiscible. In other examples, there may be additional polymers, such as a third, fourth, or even fifth polymer, that are also immiscible with the second polymer. There may also be additional compatibilizers used in combination with the first polymer or in combination with additional third, fourth, or fifth polymers. The first polymer forms polymer beads surrounded by the compatibilizer. The polymer beads may also be formed by additional polymers that are not miscible with the second polymer.

[0101] The polymer beads are surrounded by a compatibilizer and are in or mixed with the second polymer. Next, in step 102, the polymer mixture is extruded into a monofilament. Then, in step 104, the monofilament is quenched or rapidly cooled. Then, in step 106, the monofilament is reheated. In step 108, the reheated monofilament is stretched to transform the polymer beads into thread-like regions and form the monofilament into an artificial turf fiber. Additional steps may be performed on the monofilament to form the artificial turf fiber. For example, the monofilament may be spun or knitted into a yarn having desired properties. Next, in step 110, the artificial turf fiber is incorporated into an artificial turf substrate. Step 110 may be, for example, but is not limited to, tufting or weaving the artificial turf fiber into the artificial turf substrate. Then, in step 112, the artificial turf fiber is tied to the artificial turf substrate. For example, the artificial turf fiber may be glued or held in place by a coating or other material. Step 112 is an optional step. For example, if the artificial turf fibers are woven into an artificial turf substrate, step 112 may not need to be performed.

[0102] FIG. 2 shows a flow chart illustrating one method of making a polymer mixture. In this example, the polymer mixture is a three-phase system and includes a first polymer, a second polymer, and a compatibilizer. The polymer mixture may also include other additives such as additives to impart color, or provide flame or UV resistance, or improve the flow properties of the polymer mixture. First, in step 200, a first mixture is formed by mixing the first polymer with the compatibilizer. Additional additives may also be added during this step. Next, in step 202, the first mixture is heated. Next, in step 204, the first mixture is extruded. Then, in step 206, the extruded first mixture is then granulated or chopped into small pieces. Next, in step 208, the granulated first mixture is mixed with a second polymer. At this time, additional additives may also be added to the polymer mixture. Finally, in step 210, the granulated first mixture is heated with the second polymer to form the polymer mixture. The heating and mixing may be performed simultaneously.

[0103] FIG. 3 shows a flow chart illustrating a further example of how to make a polymer mixture 100. In this example, the polymer mixture additionally comprises at least a third polymer. The third polymer is immiscible with the second polymer, and the polymer mixture is at least a four-phase system. The third polymer further forms polymer beads surrounded by a compatibilizer with the second polymer. First, in step 300, a first mixture is formed by mixing the first polymer and the third polymer with a compatibilizer. At this point, additional additives may also be added to the first mixture. Next, in step 302, the first mixture is heated. The heating and mixing of the first mixture may occur simultaneously. Next, in step 304, the first mixture is extruded. Next, in step 306, the extruded first mixture is granulated or chopped into small pieces. Next, in step 308, the first mixture is mixed with a second polymer. At this time, additional additives may also be added to the polymer mixture. Then, finally, in step 310, the heated first mixture and the second polymer are heated to form a polymer mixture. The heating and mixing may occur simultaneously.

[0104] FIG. 4 shows a diagram illustrating a cross section of a polymer mixture 400. The polymer mixture 400 comprises a first polymer 402, a second polymer 404, and a compatibilizer 406. The first polymer 402 and the second polymer 404 are immiscible. The first polymer 402 is not as abundant as the second polymer 404. The first polymer 402 is shown surrounded by the compatibilizer 406 and dispersed within the second polymer 404. The first polymer 402 surrounded by the compatibilizer 406 forms many polymer beads 408. Depending on how well the polymer mixture was mixed and the temperature, the polymer beads 408 may be spherical or ovoid in shape, or they may be irregularly shaped. The polymer mixture 400 is an example of a three-phase system. The three phases are the domains of the first polymer 402. The second phase domain is the compatibilizer 406, and the third phase domain is the second polymer 404. The compatibilizer 406 separates the first polymer 402 from the second polymer 404 .

[0105] FIG. 5 shows a further example of a polymer mixture 500. The example shown in FIG. 5 is similar to that shown in FIG. 4, however, the polymer mixture 500 additionally comprises a third polymer 502. Here, some of the polymer beads 408 consist of the third polymer 502. The polymer mixture 500 shown in FIG. 5 is a four-phase system. The four phases are composed of a first polymer 402, a second polymer 404, a third polymer 502, and a compatibilizer 406. The first polymer 402 and the third polymer 502 are not miscible with the second polymer 404. The compatibilizer 406 separates the first polymer 402 from the second polymer 404 and the third polymer 502 from the second polymer 404.

[0106] In this example, the same compatibilizer 406 is used for both the first polymer 402 and the third polymer 502. In other examples, different compatibilizers 406 may be used for the first polymer 402 and the third polymer 502.

[0107] FIG. 6 illustrates the extrusion of a polymer mixture into a monofilament. A quantity of polymer mixture 600 is shown. Within the polymer mixture 600, there are a number of polymer beads 408. The polymer beads 408 may be made of one or more polymers that are not miscible with the second polymer 404, and are also separated from the second polymer 404 by a compatibilizer. A screw, piston, or other device is used to force the polymer mixture 600 into holes 604 in a plate 602. This causes the polymer mixture 600 to be extruded into a monofilament 606. The monofilament 606 is shown as also including polymer beads 408. The second polymer 404 and the polymer beads 408 are extruded together. In some instances, the second polymer 404 is not as viscous as the polymer beads 408, which will tend to concentrate in the center of the monofilament 606. This may result in desirable properties for the final artificial turf fiber, as the thread-like regions may concentrate in the core region of the monofilament 606.

[0108] 7 shows a cross-section of a small segment of monofilament 606. The monofilament is again shown as including a second polymer 404 with polymer beads 408 mixed in. The polymer beads 408 are separated from the second polymer 404 by a compatibilizer 406, not shown. To form a thread-like structure, a portion of the monofilament 606 is heated and then stretched along the length of the monofilament 606. This is illustrated by arrow 700, which indicates the direction of stretching.

[0109] Figure 8 illustrates the effect of stretching a monofilament 606. In Figure 8, an example of a cross-section of a stretched monofilament 606 is shown. The polymer bead 408 in Figure 7 has been stretched into a thread-like structure 800. The amount of deformation of the polymer bead 408 will depend on how much the monofilament 606' has been stretched.

[0110] An example may concern the production of artificial turf, also called synthetic grass. In particular, the invention concerns the production of fibers that mimic grass. The fibers consist of a first and a second polymer that are not miscible and have different material properties, such as hardness, density, polarity, and a compatibilizer.

[0111] In the first stage, the first polymer is mixed with the compatibilizer. Color pigments, UV and heat stabilizers, processing aids, and other materials known in the art as such may be added to the mixture. This may result in a granular material consisting of a two-phase system in which the first polymer is surrounded by the compatibilizer.

[0112] In the second stage, a three-phase system is formed by adding a second polymer to the mixture, whereby in this example the amount of the second polymer is about 80-90 weight percent of the three-phase system, the amount of the first polymer is 5% to 10% by weight, and the amount of the compatibilizer is 5% to 10% by weight. The use of extrusion techniques results in a mixture of droplets or beads of the first polymer surrounded by the compatibilizer, dispersed in a polymer matrix of the second polymer. In practical implementations, a so-called masterbatch is formed, which includes granules of the first polymer and the compatibilizer. In this specification, the masterbatch may also be referred to as a "polymer mixture". The granule mixture is melted and a mixture of the first polymer and the compatibilizer is formed by extrusion. The resulting strands are broken into granules. The resulting granules and the granules of the second polymer are then used in a second extrusion to produce thick fibers that are then drawn into the final fiber.

[0113] The melt temperature used during extrusion depends on the type of polymer and the compatibilizer used, however, the melt temperature is usually between 230°C and 280°C.

[0114] Monofilaments, which may also be called filaments or fibrillated tapes, are produced by sending the mixture through a fiber production extrusion line, where the molten mixture passes through an extrusion tool, i.e. a spinneret plate or wide slot nozzle, to form a molten stream in the form of a filament or tape, where it is quenched or cooled in a water spinning bath, and where it is dried and drawn by passing through heated godets and / or heated ovens rotating at different rotational speeds.

[0115] The monofilament or tape is then annealed on-line in a second stage passing through an additional heated oven and / or a set of heated godets.

[0116] By this procedure, the beads or droplets of the first polymer surrounded by the compatibilizer are stretched longitudinally to form small fibrous linear structures which, however, remain completely embedded in the polymer matrix of the second polymer.

[0117] 9 shows a microscope image of a cross-section of a drawn monofilament produced using one example of the method described above. The horizontal white stripes in the drawn monofilament 606 are thread-like structures 800. Several of these thread-like structures are labeled 800. The thread-like structures 800 may be seen to form small linear structures of a first polymer within a second polymer.

[0118] The resulting fibers can have multiple advantages: softness combined with durability and long-term resilience. If the polymers have different stiffness and flexural properties, the fibers can exhibit better resilience (meaning that the fiber bounces back when stepped on). In the case of a stiff first polymer, small linear fiber structures built into the polymer matrix provide polymer reinforcement for the fibers.

[0119] Boundary separation of the composite material formed by the first and second polymers is avoided by the fact that short fibers of the second polymer are embedded in the matrix provided by the first polymer. Furthermore, complex co-extrusion requiring several extrusion heads to feed one composite spinneret tool is not required.

[0120] The first polymer may be a polar material such as a polyamide, while the second polymer may be a non-polar polymer such as polyethylene. Alternatives for the first polymer are polyethylene terephthalate (PET) or polybutylene terephthalate (PBT), and alternatives for the second polymer are polypropylene. Finally, a material consisting of three polymers (for example PET, PA and PP) is possible, where PP creates the matrix and the others create fibrous linear structures independent of each other. The compatibilizer may be maleic anhydride grafted to polyethylene or polyamide.

[0121] FIG. 10 shows an example of a cross-section of an example of an artificial turf 1000. The artificial turf 1000 comprises an artificial turf substrate 1002. The artificial turf fibers 1004 are tufted into the artificial turf substrate 1002. A coating 1006 is shown on the bottom of the artificial turf substrate 1002. The coating can function to tie or secure the artificial turf fibers 1004 to the artificial turf substrate 1002. The coating 1006 may be optional. For example, the artificial turf fibers 1004 may alternatively be woven into the artificial turf substrate 1002. Various types of glues, coatings, or adhesives may be used for the coating 1006. The artificial turf fibers 1004 are shown extending a distance 1008 above the artificial turf substrate 1002. The distance 1008 is essentially the pile height of the artificial turf fibers 1004. The length of the thread-like region in the artificial grass fibers 1004 is half or less than the distance 1008 .

[0122] According to another embodiment of the present disclosure, which may be combined with one or more of the previously described embodiments, a method for manufacturing an artificial lawn, such as an artificial lawn 1000, comprises the steps of preparing a polymer mixture, such as a polymer mixture 400, where the polymer mixture is at least a three-phase system. The polymer mixture comprises a first polymer, a second polymer, and a compatibilizer. The first polymer is polyamide (PA) and the second polymer is polyethylene (PE). The first polymer is included in an amount of 0.125 weight percent to 5 weight percent, the second polymer is included in an amount of 60 weight percent to 97 weight percent, and the compatibilizer is included in an amount of 0.375 weight percent to 15 weight percent. The first polymer and the second polymer are immiscible, and the first polymer forms polymer beads surrounded by the compatibilizer within the second polymer.

[0123] The method may further include extruding the polymer mixture into a monofilament, quenching the monofilament, reheating the monofilament, and stretching the reheated monofilament to transform the polymer beads into a fibrous region and form the monofilament into an artificial turf fiber. The fibrous region includes a first polymer and is at least partially surrounded by a compatibilizer and separated from a second polymer by the compatibilizer. The fibrous region is centrally located such that the fibrous region does not delaminate after formation. The method may further include incorporating the artificial turf fiber into an artificial turf substrate.

[0124] In one embodiment, the polyamide is preferably nylon (e.g., nylon 6). However, the scope of the present disclosure encompasses other polyamides and may include both naturally and synthetically occurring polyamides. For example, the polyamides of the present disclosure may include naturally occurring polyamides (e.g., proteins), such as wool and silk, and synthetically created polyamides, such as aramid and sodium poly(aspartate).

[0125] In a preferred embodiment, the second polymer is a polyethylene, such as a polyethylene resin produced by DOW®, although the scope of the present disclosure encompasses other polyethylenes, such as renewable polyethylene (i.e., polyethylene produced / provided from renewable resources rather than fossil fuels). For example, the scope of the present disclosure includes polyethylene produced from sugar cane, where high and low density polyethylene is produced from bioethanol derived from sugar cane. Embodiments of the present disclosure also contemplate polyethylene made from other feedstocks, such as wheat grain and sugar beets.

[0126] Surprisingly, the applicant has found that increasing the content of the compatibilizer in the PA / PE polymer mixture, preferably comprising a first polymer present in an amount of 0.125 to 5 weight percent, a second polymer present in an amount of 60 to 97 weight percent, and a compatibilizer present in an amount of 0.375 to 15 weight percent, advantageously changes the flow characteristics of the mixture, making the mass of the mixture more uniform, thereby making the pressure and temperature of the mixture more uniform during processing of the mixture, avoiding fluctuations in energy consumption, and preventing the mixture from separating during and after extrusion from the nozzle and / or die plate. The compatibilizer and the first polymer (e.g., polyamide) may be present in the formulation in a defined ratio of about 5 parts to 1 part (5:1 part) to about 2:1 part, more preferably in a defined ratio of about 4:1 to 2.5:1, and even more preferably in a defined ratio of about 3:1.

[0127] According to another embodiment, the compatibilizer preferably comprises ethylene ethyl acrylate (i.e., a copolymer consisting of a basic resin produced by catalytic copolymerization of ethylene and ethyl acrylate). However, the scope of the present disclosure encompasses other compatibilizers, such as maleic anhydride, as disclosed above. The polymer mixture embodiments of the present disclosure can also provide the advantageous effect of faster separation at the nozzle and / or die plate (i.e., faster separation when the mixture is extruded from the nozzle and / or die plate), or in other words, a more efficient and more uniform extrusion stage that produces monofilaments with less waste material, and the advantageous effect of artificial turf fibers having greater polarity, better abrasion resistance, better elongation at break, better recovery and tensile strength, better suitability for incorporation into artificial turf substrates, and / or better suitability as field hockey yarn. Additionally, the polymer mixtures of the present invention, including ethylene ethyl acrylate compatibilizers, also optimize the service life of artificial turf fiber manufacturing machines, particularly extending the service life and / or use of extrusion machines and / or components such as nozzles and / or die plates, and extending the time between cleaning of such components (e.g., extending the time between ultrasonic cleaning). For example, embodiments of the disclosed polymer mixtures extend the time between cleaning of nozzles and / or dies from 2-3 days when using an anhydride compatibilizer to 2-3 weeks when using an ethylene ethyl acrylate compatibilizer.

[0128] In one embodiment, the weight ratio of the compatibilizer to the first polymer ranges from 2:1 to 4:1, preferably 3:1.

[0129] In yet another embodiment, the polyethylene of the second polymer comprises at least a first linear low density polyethylene (LLDPE) and a second LLDPE, the first LLDPE having a melt flow rate of about 0.9 g / 10 min to about 1.1 g / 10 min as measured according to DIN EN ISO 1133 190° C. / 2.16 kg and the second LLDPE having a melt flow rate of about 2.2 g / 10 min to about 2.4 g / 10 min as measured according to DIN EN ISO 1133 190° C. / 2.16 kg. Suitable exemplary embodiments of the LLDPE are manufactured by DOW®.

[0130] In one embodiment, the first LLDPE and the second LLDPE each have a viscosity of about 0.90 g / cm 3 to about 0.93 g / cm 3 , preferably about 0.91 g / cm 3 to about 0.925 g / cm 3 According to one embodiment, the first LLDPE has a density of 0.917 g / cm 3 and the second LLDPE has a density of 0.922 g / cm 3 has a density of

[0131] In another embodiment, the first and second LLDPEs are preferably present in the formulation in a defined ratio of about 1 part to 20 parts (1:20 parts) to about 1:4 parts, more preferably about 1:20 to 1:3 parts. The preferred ratio has the beneficial effect of reducing the separation of the PA, which is important to provide the final product with adequate wear resistance. The preferred ratio ensures that the melt flow index (MFI), also called melt index, of the formulation approaches an optimal MFI, which in one embodiment corresponds to the MFI of the second LLDPE. The reduction of separation is particularly relevant when pressure drops occur in the extrusion nozzle and / or die.

[0132] Table 1 shows seven sample formulations, each having a particular weight ratio of the first LLDPE to the second LLDPE, a calculated MFI, a measured MFI, and a precision between the calculated and measured MFI. The MFI of a particular sample depends on the MFI of the first and second LLDPEs. [Table 1]

[0133] In one embodiment, the weight ratio of the first LLDPE to the second LLDPE is between 1:20 and 1:3 and the melt flow index (also called melt flow rate) of the blend of the first LLDPE and the second LLDPE is from about 1.95 g / 10 min to about 2.25 g / 10 min when measured according to DIN EN ISO1133 190° C. / 2.16 kg.

[0134] According to another embodiment, the polyethylene of the second polymer further comprises high density polyethylene (HDPE), the HDPE having a melt flow rate of about 3.9 g / 10 min to about 4.1 g / 10 min as measured according to DIN EN ISO 1133 190° C. / 2.16 kg, and the HDPE is present in an amount of 0.1 weight percent to 15 weight percent. In yet another embodiment, the HDPE has a melt flow rate of about 0.93 g / cm 3 to about 0.97 g / cm 3 of about 0.95 g / cm 3 to about 0.96 g / cm 3 has a density of

[0135] In one embodiment, the polymer mixture further comprises a processing aid additive. The processing aid additive advantageously reduces the viscosity of the polymer mixture (also called the processing mixture melt) during processing, reducing or preventing the accumulation of deposits on extruder components such as the extruder screw, extruder housing, and nozzle and / or die plate. The processing aid additive may comprise a fluoropolymer-based processing additive, a siloxane, or a combination thereof. The processing aid additive may be included in an amount of 0.1 weight percent to 1.0 weight percent.

[0136] Conventional processing aid additives, such as products by BYK-Altana and 3M (e.g., Dynamar®), contain long-chain polyfluoropolymers, such as long-chain polyfluoroalkyl compounds. Although there are currently environmental concerns about the use of short-chain polyfluoropolymers (e.g., short-chain polyfluoroalkyl substances (PFAS)), it is difficult to distinguish analytically between long-chain polyfluoropolymers and short-chain polyfluoropolymers, and as a result, artificial turf fibers are only tested for the presence of fluorine. When the presence of fluorine is detected, regulatory agencies usually conclude that short-chain PFAS is likely to be present at least as an impurity. Therefore, one advantage of using only siloxanes as processing aid additives is that, in addition to obtaining fluorine-free formulations and fluorine-free products, it also eliminates any doubt about whether the formulations and products contain short-chain polyfluoropolymers, thereby reducing any concerns that the products are harmful to the environment.

[0137] In a preferred embodiment, the processing aid additive of the present disclosure is a siloxane. In another embodiment, the siloxane is included in the polymer mixture in an amount of 0.5 wt% to result in a fluorine-free mixture and fiber product. In addition to addressing environmental / toxicological concerns, the use of siloxane as a processing aid additive can also reduce deposits that may occur during processing of PA / PE blends (i.e., mixtures). As described above, compatibilizers can reduce deposits, but deposits can still accumulate on processing machinery components, such as those associated with the extrusion process. Using only siloxane formulations has the technical effect of extending die and / or nozzle life from about 24 hours to up to 72 hours.

[0138] In yet another embodiment, the polymer blend may further include a polymeric protection blend having at least one of a hindered amine light stabilizer, an antioxidant, an oxygen scavenger, a third LLDPE, and / or a filler and a pigment. The polymeric protection blend may be included in an amount of 3.0 weight percent to 15.0 weight percent. In one embodiment, the protection blend may be included in about 10 weight percent of the polymer blend, and the protection blend itself may include: (1) 14 weight percent of the hindered amine light stabilizer, antioxidant, and oxygen scavenger; (2) 45-65 weight percent of the third LLDPE (e.g., a polymeric carrier); and (3) 31-41 weight percent of the filler and pigment.

[0139] In another embodiment, the polymer blend comprises 0.125 to 5 weight percent of the first polymer, 0.375 to 15 weight percent of a compatibilizer, 3 to 15 weight percent of a polymeric protection blend including at least one of a hindered amine light stabilizer, an antioxidant, an oxygen scavenger, a third LLDPE, a filler, and a pigment, and 0.1 to 1.0 weight percent of a processing aid additive, the processing aid additive being a fluoropolymer-based processing additive, a siloxane, or a combination thereof. The second polymer comprises 20 to 75 weight percent of a first linear low density polyethylene (LLDPE), the first LLDPE having a melt flow rate of about 0.9 g / 10 min to about 1.1 g / 10 min as measured according to DIN EN ISO 1133 at 190° C. / 2.16 kg, 5 to 25 weight percent of a second LLDPE, the second LLDPE having a melt flow rate of about 2.2 g / 10 min to about 2.4 g / 10 min as measured according to DIN EN ISO 1133 at 190° C. / 2.16 kg, and 0.01 to 15 weight percent of a high density polyethylene (HDPE), the HDPE having a melt flow rate of about 3.9 g / 10 min to about 4.1 g / 10 min as measured according to DIN EN ISO 1133 at 190° C. / 2.16 kg.

[0140] According to yet another embodiment, the polymer blend comprises 0.25 to 2.5 weight percent of a first polymer, 0.75 to 7.5 weight percent of a compatibilizer, 4 to 11 weight percent of a polymeric protection blend including at least one of a hindered amine light stabilizer, an antioxidant, an oxygen scavenger, a third LLDPE, a filler, and a pigment, and 0.15 to 0.75 weight percent of a processing aid additive, where the processing aid additive is a fluoropolymer-based processing additive, a siloxane, or a combination thereof. The second polymer comprises 55 to 70 weight percent of a first linear low density polyethylene (LLDPE), the first LLDPE having a melt flow rate of about 0.9 g / 10 min to about 1.1 g / 10 min as measured according to DIN EN ISO 1133 190° C. / 2.16 kg, 10 to 20 weight percent of a second LLDPE, the second LLDPE having a melt flow rate of about 2.2 g / 10 min to about 2.4 g / 10 min as measured according to DIN EN ISO 1133 190° C. / 2.16 kg, and 8 to 14 weight percent of a high density polyethylene (HDPE), the HDPE having a melt flow rate of about 3.9 g / 10 min to about 4.1 g / 10 min as measured according to DIN EN ISO 1133 190° C. / 2.16 kg.

[0141] In one embodiment, the polymer beads include crystalline and amorphous portions, and stretching the polymer beads into fibrous (ie, thread-like) regions increases the size of the crystalline portions relative to the amorphous portions.

[0142] In another embodiment, preparing the polymer mixture includes forming a first mixture by mixing a first polymer with a compatibilizer, heating the first mixture, extruding the first mixture, granulating the extruded first mixture, mixing the granulated first mixture with a second polymer, and heating the granulated first mixture with the second polymer to form the polymer mixture.

[0143] FIG. 11 shows a radial cross section of a monofilament 1100 for producing artificial grass fibers according to one embodiment of the present disclosure. The radial cross section (i.e., cut end) is oriented perpendicular to the central axis of the monofilament 1100. It comprises a circular bulge 1101 containing a cylindrical core 1102, and a non-circular cladding 1104 surrounding the core 1102. The core 1102 comprises a core polymer 1106, and a thread-like (i.e., fiber) region 1108 embedded in the core polymer 1106. The thread-like region is formed from a thread polymer, which is preferably a polymer with high bending stiffness or hardness. In one embodiment, the thread-like region is formed from a first polymer 402 (see, e.g., FIG. 4). In one embodiment, the first polymer is a polyamide, preferably nylon (e.g., nylon 6). The thread-like region spans the core polymer 1106 axially and at random radial positions and / or orientations.

[0144] The core polymer 1106 occupies the majority of the core volume and may be any polymer that is miscible with the cladding polymer that forms the cladding 1104. Because the core polymer 1106 occupies the largest portion of the core 1102, it is preferably chosen to be a relatively inexpensive material. In one embodiment, the core polymer 1106 is the second polymer 404 (see, e.g., FIG. 4). In one embodiment, the second polymer is polyethylene (e.g., polyethylene resin). The core polymer 1106 may be immiscible with the yarn polymer 1108. In this case, although not shown in FIG. 11, the fiber region is surrounded by a compatibilizer (as illustrated by FIG. 4 showing that the compatibilizer 406 (FIG. 4) surrounds the fiber region 402) and has the ability to emulsify the yarn polymer 1108 with the liquid core polymer 1106. In one preferred embodiment, the compatibilizer (e.g., compatibilizer 406) surrounding the fiber region 1108 is ethylene ethyl acrylate. However, the scope of the present disclosure encompasses other compatibilizers, such as maleic anhydride. After fabrication, the thread-like regions remain intimately attached to the core polymer 1106 within the solidified monofilament 1100.

[0145] According to one embodiment of the present disclosure, the monofilament 1100 includes two lobes 1110a, 1110b. The two lobes are lobes of a non-circular cladding 1104 that surrounds a core 1102.

[0146] In another embodiment, extruding the polymer mixture into a monofilament includes co-extruding the polymer mixture (e.g., polymer mixture 400, FIG. 4) with a liquid cladding polymer component (not shown). Upon co-extrusion, the polymer mixture forms a cylindrical core 1102 (e.g., a liquid cylindrical core) and the liquid cladding polymer component forms a cladding 1104 surrounding the core 1102.

[0147] In one embodiment, the cladding 1104 has a non-circular profile, such as the non-circular profile illustrated by Figure 11 having two lobes 1110a, 1110b. Although Figure 11 shows a cladding having a non-circular profile illustrated with two opposing lobes 1110a, 1110b, the scope of the present invention encompasses cladding having any type of non-circular profile, including one or more lobes. The scope of the present disclosure also encompasses opposing and / or non-opposing lobes.

[0148] In one embodiment, as shown, the profile of at least one of the protrusions includes a concave side (see, e.g., FIG. 12, 1210). However, the scope of the present disclosure includes protrusions or portions of protrusions having a profile with a non-concave side (e.g., a convex side or a straight side).

[0149] In one embodiment, the cladding 1104 is formed by a cladding polymer chosen to be miscible with the core polymer 1106 in a fluid state. The cladding polymer may be the same as the core polymer 1106. The annular cylindrical zone or area where the cladding polymer meets the core polymer 1106 is an interface layer (not shown) where both polymers are intermixed with each other. Thus, the interface layer may bond the core 1106 and cladding 1104 together with stronger long-range forces than would normally occur in an arrangement with merely a tight bond.

[0150] The cladding 1104 is preferably formed from a polymer such as polyethylene, which can provide soft and smooth surface properties. The cladding 1104 can include additives that support its function of interfacing with the environment and / or the user. Typical additives to the cladding 1104 can be, for example, pigments to provide a particular color, matting agents, UV stabilizers, flame retardant materials such as aramid fibers or intumescent additives, antioxidants, fungicides, and / or waxes to increase the softness of the cladding 1104.

[0151] Providing additives in the cladding 1104 may have the advantage that these can remain outside the core 1102. In this way, a smaller content of expensive additive material per unit mass is required. As an example, since only the cladding 1104 is visible from the outside, there is no need to add pigments to the core 1102. As a more specific example, it may be beneficial to add green pigments, colorants, and waxes to the cladding 1104 to more closely resemble natural grass blades.

[0152] The non-circular profile of the cladding 1104 may be symmetrical or irregular, polygonal, elliptical, lenticular, flat, pointed or elongated. The cladding 1104 preferably resembles a blade of grass by surrounding a circular cylindrical core 1102 with two convex segments extending in two opposite directions from the geometric center of the monofilament and two protrusions 1110a, 1110b, which may be flat protrusions, extending in another two opposite directions from the geometric center of the monofilament. The convex segments and protrusions 1110a, 1110b may be joined alternately by convex segments such as convex side segment 1112. When the two protrusions 1110a, 1110b are substantially flat compared to the diameter of the core with the cladding surrounding the core, they can also increase the biomimetic properties of the monofilament 1110 and can increase the surface area to mass ratio of each monofilament 1100, thereby providing improved surface coverage in artificial turf produced from artificial turf fibers based on such monofilaments 1110.

[0153] In one embodiment, monofilament 1100, which may also be referred to as filament, may be produced by sending a core polymer mixture, such as polymer mixture 400, and a cladding polymer component to a fiber production co-extrusion line (not shown). The two polymer melt components are prepared separately from each other and then merge together at a co-extrusion tool, i.e., a spinneret plate, to form two melt streams into a filament, which is quenched or cooled in a water spinning bath, dried and drawn by passing through heated godets rotating at different rotational speeds and / or heated ovens.

[0154] FIG. 12 shows a radial cross-section of a monofilament 1200 for producing artificial grass fibers according to another embodiment of the present disclosure. The radial cross-section (i.e., cut end) is oriented perpendicular to the central axis of the monofilament 1200. The monofilament 1200 includes a polymer 1202 and a thread-like (i.e., fiber) region 1204 embedded in the polymer 1202. The thread-like region is formed from a thread polymer, which is preferably a polymer with high bending stiffness or hardness. In one embodiment, the thread-like region is formed from a first polymer 402 (see, e.g., FIG. 4). In one embodiment, the first polymer is a polyamide, preferably nylon (e.g., nylon 6). The thread-like region spans the polymer 1202 axially and at random radial positions and / or orientations. In one embodiment, the polymer 1202 is a second polymer 404 (see, e.g., FIG. 4). In one embodiment, the second polymer is polyethylene (e.g., polyethylene resin).

[0155] The polymer 1202 may be immiscible with the yarn polymer 1204. In this case, although not shown in FIG. 12, the fiber regions are surrounded by a compatibilizer (as illustrated by FIG. 4 showing compatibilizer 406 (FIG. 4) surrounding the fiber regions 402) and have the ability to emulsify the yarn polymer 1204 with the liquid polymer 1202. In a preferred embodiment, the compatibilizer (e.g., compatibilizer 406) surrounding the fiber regions 1204 is ethylene ethyl acrylate. In another embodiment, the compatibilizer is maleic anhydride. After fabrication, the thread regions remain intimately attached to the polymer 1202 within the solidified monofilament 1200.

[0156] According to one embodiment of the present disclosure, the monofilament 1200 includes a circular bulge 1206 and two lobes 1208a, 1208b extending from the circular bulge 1206. In one embodiment, the shape of the monofilament 1200 including the circular bulge 1206 and the two lobes 1208a, 1208b is formed upon extrusion of the mixture through a nozzle plate or die.

[0157] In one embodiment, as shown, the profile of at least one of the protrusions includes a concave side (see, e.g., FIG. 12, 1210). However, the scope of the present disclosure includes protrusions or portions of protrusions having a profile with a non-concave side (e.g., a convex side or a straight side).

[0158] The profile of the monofilament 1200 may be symmetrical or irregular; polygonal, elliptical, lenticular, flat, pointed or elongated. The circular bulge 1206 and the two flat protrusions 1208a, 1208b extending in opposite directions from the geometric center of the monofilament are preferably shaped to resemble blades of grass. When the two protrusions 1208a, 1208b are substantially flat compared to the approximate diameter of the circular bulge 1206, the biomimetic properties of the monofilament 1200 can also be increased, and the surface area to mass ratio of each monofilament 1200 can be increased, correspondingly providing improved surface coverage in artificial turf produced from artificial turf fibers based on such monofilaments 1200.

[0159] 13 shows a cross-sectional profile of a wavy artificial grass fiber 1300 with a central circular bulge 1302 and two lobes 1304a, 1304b with rounded tips 1306, according to one embodiment of the disclosure. The circular bulge 1302 may include a core, such as the cylindrical core 1102 of FIG. 11, however, the scope of the disclosure encompasses circular bulges 1302 that do not include a cylindrical core. According to one embodiment, the wavy artificial grass fiber 1300 is a wavy version of the artificial grass fiber 1100, and in another embodiment, the wavy artificial grass fiber 1300 is a wavy version of the artificial grass fiber 1200.

[0160] The profile extends over an overall thickness t between the forward portion of the central bulge 1302 and the rearward portion of the tip 1306 of the protrusion. The distance between the two tips 1306 is the overall width w of the fiber 1300. Both protrusions may have a profile with one straight side 1308 and one wavy side 1310 opposite the straight side 1308 with multiple notches along a straight reference line. Considering that the fiber extends axially (i.e., into and out of the 2d drawing), this profile corresponds to a protrusion with one flat side and one grooved side. However, the scope of the present disclosure encompasses one or more protrusions having a profile or a portion of a profile with a straight side 1308, a wavy side 1310, a convex side (not shown) and / or a concave side (shown as optional concave side 1312).

[0161] The protrusions may include angles between 100 and 180 degrees. In the non-limiting example shown, the protrusions subtend an angle of about 135 degrees toward the wavy side 1310 of the profile. Both protrusions have a radial extension of about three times the thickness of the bulge 1302. Assuming, for demonstration purposes only, an exemplary overall profile width w=1.35 mm, and an overall thickness t=0.45 mm, the profile of FIG. 13 has a radial extension of about 0.216 mm. 2 Exemplary average density is 0.92 g / mm 2 In practice, this corresponds to a yarn weight of approximately 2000 dtex.

[0162] In one embodiment, the profile of at least one of the protrusions includes an undulating section 1310 across at least 60% of one side of the protrusion.

[0163] In yet another embodiment, the coextrusion is carried out at an operating temperature between 180 and 270°C.

[0164] According to another embodiment, the first polymer and the second polymer are polymers formed from renewable resources. For example, the first polymer may be a renewable polyamide (e.g., protein) such as wool and silk, and the second polymer may be a renewable polyethylene such as polyethylene produced from sugar cane, where high and low density polyethylene is produced from bioethanol derived from sugar cane. Embodiments of the present disclosure also contemplate polyethylene made from other feedstocks such as wheat grain and sugar beet.

[0165] Suitable carbon sources for the renewable resources to form the first and / or second polymers can be provided by manufacturing processes or any other natural or artificial materials or processes that can be used to produce the desired substances. For example, the polymers may be made from renewable resources such as polysaccharides, e.g., cellulose, starch, chitosan, lignin, and proteins, e.g., wool, silk, and gelatin, oils, and microbially produced poly(esters), e.g., PHAs. Any type of carbon source used to produce a material whose 14C atom content is similar or essentially identical to the 14C content of the biomass of currently living organisms is called a renewable carbon source. Atmospheric CO2 is a source of radioactive carbon C14. Fossil (petroleum-based) carbon sources contain smaller amounts of the radioactive C14 isotope and can therefore be distinguished from renewable (bio-based) carbon sources by performing isotopic analysis (radiocarbon dating). After 5700 years, roughly half of all 14C atoms decay.

[0166] According to one embodiment, the compatibilizer is maleic anhydride grafted polyethylene.

[0167] According to some embodiments, the maleic anhydride grafted polyethylene is 0.5 to 1 weight percent of the polymer blend.

[0168] According to a preferred embodiment, the maleic anhydride grafted polyethylene has a viscosity of 0.83 to 1.03 g / cm3 as measured by the displacement method (i.e., ASTM D792, ISO 1183 test method). 3 Density of preferably 0.93 g / cm 3 and / or a melt flow index measured at 190° C. / 2.16 kg (i.e., ASTM D1238, ISO 1133 test method) of 1.575 g / 10 min to 1.925 g / 10 min, preferably 1.75 g / 10 min.

[0169] According to some embodiments, the first polymer is present in an amount of 0.1 to 30 weight percent of the second polymer. In other embodiments, the first polymer is present in an amount less than or equal to 10 weight percent of the second polymer, preferably 0.4 to 10 weight percent of the second polymer, and more preferably 0.5 weight percent of the second polymer. In yet other embodiments, the first polymer is present in an amount of 0.1 to 5 weight percent of the second polymer, preferably 0.4 to 5 weight percent of the second polymer, and more preferably 0.4 to 1.0 weight percent of the second polymer.

[0170] According to another embodiment, the present disclosure provides an artificial turf produced by the steps of: preparing a polymer mixture, where the polymer mixture is at least a three-phase system, where the polymer mixture comprises a first polymer, a second polymer, and a compatibilizer, where the first polymer is polyamide (PA) and the second polymer is polyethylene (PE), where the first polymer is present in an amount of 0.125 weight percent to 5 weight percent, the second polymer is present in an amount of 60 weight percent to 97 weight percent, and the compatibilizer is present in an amount of 0.375 weight percent to 15 weight percent, where the first polymer and the second polymer are immiscible, and the first polymer forms polymer beads surrounded by the compatibilizer within the second polymer; extruding, quenching, reheating, and stretching the polymer mixture to transform the polymer beads into fibrous regions and form monofilaments into artificial turf fibers; and incorporating the artificial turf fibers into an artificial turf substrate. The compatibilizer is preferably ethylene ethyl acrylate (EEA) or maleic anhydride grafted polyethylene.

[0171] In one embodiment, the artificial turf fibers extend a predetermined length beyond the artificial turf substrate and the fiber region has a length that is less than half of the predetermined length.

[0172] In another embodiment, the fiber region has a length less than 2 mm.

[0173] According to another embodiment, the present disclosure provides an artificial turf comprising an artificial turf substrate; and an artificial turf yarn comprising a plurality of fibers, each of the plurality of fibers comprising a polyamide fiber region substantially surrounded by a compatibilizer comprising ethylene ethyl acrylate and polyethylene. The compatibilizer is located between the polyamide and the polyethylene, such that the fiber region is centrally located and does not delaminate.

[0174] In another embodiment, the fibrous region has a diameter between 1 and 3 micrometers and a length less than 2 mm.

[0175] In another embodiment, each of the plurality of fibers comprises a monofilament, the monofilament having a diameter between 170 micrometers and 600 micrometers.

[0176] In another embodiment, the artificial turf yarn comprises a plurality of yarn bundles, each of which comprises some of the fibers of the plurality of fibers twisted together and wrapped with a rewinding yarn.

[0177] [Explanation of symbols] 100 Create a polymer mixture 102 Extrusion of polymer mixture into monofilament 104 Quenching monofilament 106 Reheating monofilament 108 Stretching the reheated monofilament to transform the polymer beads into thread-like regions and form the monofilament into artificial turf fibers. 110 Incorporating artificial grass fibers into artificial grass carpet 112 Optionally tie the artificial grass fibers into an artificial grass carpet 200 Forming a first mixture by mixing a first polymer with a compatibilizer 202 Heat the first mixture 204 Extrude the first mixture 206 Granulating the extruded first mixture 208 Mixing the granulated first mixture with a second polymer 210 Heating the granulated first mixture with a second polymer to form a polymer mixture. 300 Forming a first mixture by mixing a first polymer and a third polymer with a compatibilizer. 302 Heat the first mixture 304 Extrude the first mixture 306 Granulating the extruded first mixture 308 Mixing the first mixture with a second polymer 310 Heating the mixed first mixture with a second polymer to form a polymer mixture. 400 Polymer Mixture 402 1st Polymer 404 2nd Polymer 406 Compatibilizer 408 Polymer Beads 500 Polymer Mixture 502 3rd Polymer 600 Polymer Mixture 602 Plate 604 holes 606 Monofilament 606' Drawn Monofilament 700 Stretching direction 800 Thread-like Structure 1000 Artificial Grass 1002 Artificial Grass Carpet 1004 Artificial grass fiber (pile) 1006 Coating 1008 Pile height 1100 Monofilament 1101 Circular bulge 1102 Core 1104 Cladding 1106 Core Polymer 1108 Textiles 1110 Protrusion 1112 Convex Segment 1200 Monofilament 1202 Polymer 1204 Textiles 1206 Circular Bulge 1208 Protrusion 1212 Convex Segment 1300 Textile 1302 Circular Bulge 1304 Protrusion 1306 Tip 1308 Straight side 1310 Wavy side 1312 Concave side

Claims

1. creating a polymer mixture, wherein said polymer mixture is at least a three-phase system, wherein said polymer mixture comprises a first polymer, a second polymer, and a compatibilizer, wherein said first polymer and said second polymer are immiscible, and wherein said first polymer forms polymer beads surrounded by said compatibilizer within said second polymer; extruding the polymer mixture into monofilaments; quenching the monofilament; reheating the monofilament; stretching the reheated monofilament to transform the polymer beads into a fiber region and form the monofilament into an artificial turf fiber, the fiber region comprising the first polymer, the fiber region being at least partially surrounded by the compatibilizer and separated from the second polymer by the compatibilizer, the fiber region being centrally located such that the fiber region does not delaminate after formation; Incorporating the artificial grass fiber into an artificial grass base A method for producing an artificial lawn comprising:

2. 10. The method of claim 1, wherein the first polymer comprises a polyamide and the second polymer comprises a polyethylene, the first polymer is present in an amount of 0.125 weight percent to 5 weight percent, the second polymer is present in an amount of 60 weight percent to 97 weight percent, and the compatibilizer is present in an amount of 0.375 weight percent to 15 weight percent.

3. 10. The method of any one of the preceding claims, wherein the compatibilizer is included in an amount of 0.5 to 1.0 weight percent.

4. 10. The method of any one of the preceding claims, wherein the compatibilizer is maleic anhydride grafted polyethylene.

5. 4. The method of claim 1, wherein the compatibilizer is or comprises ethylene ethyl acrylate.

6. 10. The method of any one of the preceding claims, wherein the polyethylene of the second polymer comprises at least a first linear low density polyethylene (LLDPE) and a second LLDPE, the first LLDPE having a melt flow rate of from about 0.9 g / 10 min to about 1.1 g / 10 min as measured according to DIN EN ISO 1133 190°C / 2.16 kg and the second LLDPE having a melt flow rate of from about 2.2 g / 10 min to about 2.4 g / 10 min as measured according to DIN EN ISO 1133 190°C / 2.16 kg.

7. 7. The method of claim 6, wherein the weight ratio of the first LLDPE to the second LLDPE is between 1:20 and 1:3, and the melt flow rate of the mixture of the first LLDPE and the second LLDPE is from about 1.95 g / 10 min to about 2.25 g / 10 min as measured according to DIN EN ISO 1133 190° C. / 2.16 kg.

8. 8. The method of claim 6 or 7, wherein the polyethylene of the second polymer further comprises high density polyethylene (HDPE), the HDPE having a melt flow rate of from about 3.9 g / 10 min to about 4.1 g / 10 min as measured according to DIN EN ISO 1133 190° C. / 2.16 kg, and the HDPE is present in an amount of from 0.1 weight percent to 15 weight percent.

9. 2. The method of any preceding claim, wherein the polymer mixture further comprises a processing aid additive, the processing aid additive comprising a fluoropolymer-based processing additive, a siloxane, or a combination thereof, the processing aid additive being present in an amount of 0.1 weight percent to 1.0 weight percent.

10. 10. The method of any preceding claim, wherein the polymer blend further comprises a polymer protection blend comprising at least one of a hindered amine light stabilizer, an antioxidant, an oxygen scavenger, a third LLDPE, a filler, and a pigment, the polymer protection blend being present in an amount of 3.0 weight percent to 15.0 weight percent.

11. The polymer mixture comprises: 0.125 to 5 weight percent of said first polymer; 0.375 to 15 weight percent of said compatibilizer; 3 to 15 percent by weight of a polymeric protective mixture comprising at least one of a hindered amine light stabilizer, an antioxidant, an oxygen scavenger, a third LLDPE, a filler, and a pigment; and 0.1 to 1.0 weight percent of a processing aid additive, wherein the processing aid additive comprises a fluoropolymer-based processing additive, or a siloxane; It consists of: The second polymer is 20 weight percent to 75 weight percent of a first linear low density polyethylene (LLDPE), the first LLDPE having a melt flow rate of about 0.9 g / 10 min to about 1.1 g / 10 min as measured according to DIN EN ISO 1133 190° C. / 2.16 kg; 5 weight percent to 25 weight percent of a second LLDPE, the second LLDPE having a melt flow rate of about 2.2 g / 10 min to about 2.4 g / 10 min as measured according to DIN EN ISO 1133 190° C. / 2.16 kg; and 0.01 weight percent to 15 weight percent of high density polyethylene (HDPE), the HDPE having a melt flow rate of about 3.9 g / 10 min to about 4.1 g / 10 min as measured according to DIN EN ISO 1133 190° C. / 2.16 kg; 2. A method according to any preceding claim, comprising:

12. The polymer mixture comprises: 0.25 to 2.5 weight percent of said first polymer; 0.75 to 7.5 weight percent of said compatibilizer; 4 to 11 percent by weight of a polymeric protective mixture comprising at least one of a hindered amine light stabilizer, an antioxidant, an oxygen scavenger, a third LLDPE, a filler, and a pigment; and 0.15 to 0.75 weight percent of a processing aid additive, wherein the processing aid additive comprises a fluoropolymer-based processing additive, or a siloxane; It consists of: The second polymer is 55 weight percent to 70 weight percent of a first linear low density polyethylene (LLDPE), the first LLDPE having a melt flow rate of about 0.9 g / 10 min to about 1.1 g / 10 min as measured according to DIN EN ISO 1133 190° C. / 2.16 kg; 10 weight percent to 20 weight percent of a second LLDPE, the second LLDPE having a melt flow rate of about 2.2 g / 10 min to about 2.4 g / 10 min as measured according to DIN EN ISO 1133 190° C. / 2.16 kg; and 8 weight percent to 14 weight percent high density polyethylene (HDPE), the HDPE having a melt flow rate of about 3.9 g / 10 min to about 4.1 g / 10 min as measured according to DIN EN ISO 1133 190° C. / 2.16 kg; 2. A method according to any preceding claim, comprising:

13. 10. The method of any preceding claim, wherein the polymer beads comprise crystalline and amorphous portions, and stretching the polymer beads into the fibrous region increases the size of the crystalline portions relative to the amorphous portions.

14. The step of forming the polymer mixture comprises: forming a first mixture by combining said first polymer with said compatibilizing agent; heating the first mixture; extruding the first mixture; granulating the extruded first mixture; mixing the granulated first mixture with the second polymer; and heating the granulated first mixture with the second polymer to form the polymer mixture.

13. The method of any preceding claim, comprising:

15. 2. The method of any one of the preceding claims, wherein the drawn monofilament comprises a circular bulge and two lobes extending in opposite directions from the circular bulge.

16. 10. The method of claim 1, wherein the step of extruding the polymer mixture into a monofilament comprises co-extruding the polymer mixture with a liquid cladding polymer component, the polymer mixture forming a cylindrical core and the liquid cladding polymer component forming a cladding surrounding the core, the cladding having a non-circular profile.

17. 17. The method of claim 16, wherein the step of co-extruding further comprises forming the cladding with two lobes extending in opposite directions from the core.

18. The method of claim 16 , wherein the profile of at least one of the protrusions includes a concave side.

19. The method of claim 16 , wherein the profile of at least one of the protrusions includes an undulating section across at least 60% of a side of the at least one protrusion.

20. 10. The method of any preceding claim, wherein the first polymer and the second polymer are polymers formed from renewable resources.

21. An artificial turf fiber comprising a fiber region of a first polymer, the fiber region being substantially surrounded by a compatibilizer and a second polymer, the compatibilizer being located between the first polymer and the second polymer, such that the fiber region is centrally located and does not delaminate.

22. 22. The artificial grass fiber of claim 21, wherein the compatibilizer is maleic anhydride grafted polyethylene or ethylene ethyl acrylate.

23. the first polymer comprises a polyamide and the second polymer comprises a polyethylene; the first polymer is present in an amount of 0.125 weight percent to 5 weight percent; the second polymer is present in an amount of 60 weight percent to 97 weight percent; The compatibilizer is present in an amount of 0.375 to 15 weight percent, particularly in an amount of 0.5 to 1.0 weight percent.

23. The artificial grass fiber of any one of claims 21 to 22.

24. Artificial turf substrate; and A plurality of artificial grass fibers according to any one of claims 21 to 23. Equipped with artificial turf.

25. An artificial lawn obtainable by the manufacturing method according to any one of claims 1 to 20.

26. 26. The artificial turf of claim 24 or 25, wherein the artificial turf fibres extend a predetermined length beyond the artificial turf substrate, and the fibre regions have a length that is less than half of the predetermined length.

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