ARTIFICIAL TURF SYSTEM INCLUDING TWO ELASTIC LAYERS AND A GEOGRID

Abstract

An artificial turf system (100, 500) comprises an artificial turf layer (102), an upper elastic layer (104) positioned below the artificial turf layer, and a geogrid (106). The geogrid is positioned between the first elastic layer and a lower elastic layer. The lower elastic layer (108) is positioned below the geogrid.

Claims

1. An artificial turf system (100, 500) comprising: an artificial turf layer (102); an upper elastic layer (104) positioned below the artificial turf layer; a geogrid (106) positioned between the first elastic layer and a lower elastic layer; and the lower elastic layer (108) positioned below the geogrid.

2. The artificial turf system according to claim 1, wherein the artificial turf is free of an infill layer (508) or comprises an infill layer (508) having a height of less than 1 cm.

3. The artificial turf system according to claim 1, wherein the upper and/or the lower elastic layer has a height of 0.8 cm to 4.0 cm, more preferably 2.5 to 3.0 cm.

4. The artificial turf system according to claim 1, wherein the elasticity of the upper and the lower elastic layers and the thickness of the geogrid are adapted to each other such that the lower surface of the upper elastic layer (104) and the upper surface of the lower elastic layer (108) contact each other except at regions where the ribs (112, 114) of the geogrid separate the upper and the lower elastic layer.

5. The artificial turf system according to claim 1, wherein the upper and/or the lower elastic layer is made of a mixture of elastic granules (204) and a binder (202).

6. The artificial turf system according to claim 5, the binder being a polyurethane binder.

7. The artificial turf system according to claim 5, the mixture further comprising fibers (302).

8. The artificial turf system of claim 7, wherein the fibers are non-stretchable.

9. The artificial turf system of claim 7, wherein the fibers have a random orientation within the binder.

10. The artificial turf system of claim 7, wherein the fibers have a length of at least 1 cm, preferably of at least 2 cm.

11. The artificial turf system of claim 7, wherein more than 60% of the fibers have a length of 1-5 cm, preferably 3-4 cm.

12. The artificial turf system of claim 7, wherein the fibers have different lengths and wherein, preferably, the difference between the length of the shortest 10% of the fibers and the length of the longest 10% of the fibers is at least 3 cm, preferably at least 4 cm.

13. The artificial turf system of claim 7, wherein the fibers are plant fibers, synthetic fibers, or a mixture of plant fibers and synthetic fibers.

14. The artificial turf system of claim 7, the fibers being selected from the group consisting of jute fibers, hemp fibers, corn silk fibers, flax fibers, bamboo fibers, kapok fibers, sisal fibers, coconut fibers, cotton fibers, cellulose fibers, polyethylene fibers, polyamide fibers, polypropylene fibers, nylon fibers, polyester fibers, glass fibers, fibers made of rubber, fibers made of Ethylen-Propylen-Dien (EPDM) rubber, Styrene Butadiene Rubber (SBR)) and mixtures thereof.

15. The artificial turf system of claim 7, the fibers comprising synthetic fibers comprising a nucleating agent.

16. The artificial turf system of claim 15, the nucleating agent being be an inorganic substance selected from the group consisting of talcum, kaolin, calcium carbonate, magnesium carbonate, silicate, silicic acid, silicic acid ester, aluminum trihydrate, magnesium hydroxide, meta- and/or polyphosphates, and coal fly ash.

17. The artificial turf system of claim 15, the nucleating agent being an organic substance selected from the group consisting of 1,2-cyclohexane dicarbonic acid salt, benzoic acid, benzoic acid salt, sorbic acid, and sorbic acid salt.

18. A method for manufacturing an artificial turf system (100, 500) comprising: placing (402) a lower elastic layer (108) on a base layer (110); placing (404) a geogrid (106) on the lower elastic layer (108); placing (406) an upper elastic layer (104) on the geogrid; and placing (408) an artificial turf (102) on the upper elastic layer.

19. The method of claim 18, wherein the placing of the lower elastic layer is performed by applying a first liquid polyurethane reaction mixture on the base layer and allowing the first reaction mixture to solidify into the lower elastic layer; and wherein the placing of the upper elastic layer is performed by applying a second liquid polyurethane reaction mixture on the geogrid and allowing the second reaction mixture to solidify into the upper elastic layer.

20. The method of claim 18, wherein the placing of the lower elastic layer is performed by laying first prefabricated elastic tiles on the base layer; wherein the placing of the upper elastic layer is performed by laying second prefabricated elastic tiles on the geogrid.

Description

[0074] The following embodiments of the invention are explained in greater detail, by way of example only, making reference to the following figures:

[0075] FIG. 1A is a cross-sectional view of an artificial turf system;

[0076] FIG. 1B is another cross-sectional view of the artificial turf system depicted in FIG. 1A;

[0077] FIG. 2 is a schematic, cross-sectional view of a lower e-layer comprising elastic granules;

[0078] FIG. 3 is a schematic, cross-sectional view of a lower e-layer comprising elastic granules and fibers;

[0079] FIG. 4 is a flowchart of a method of producing an artificial turf system;

[0080] FIG. 5 is a schematic, cross-sectional view of an artificial turf system comprising a fill layer; and

[0081] FIG. 6 illustrates the installation of the individual layers of an artificial turf system.

DETAILED DESCRIPTION

[0082] FIG. 1A is a cross-sectional view of an artificial turf system 100. It comprises an artificial turf layer 102, an upper e-layer 104, a geogrid 106, and a lower e-layer 108. The geogrid comprises multiple nodes 114 corresponding to regions where two groups of parallel ribs intersect and are connected to each other. FIG. 1A shows a cross-section of the artificial turf system that was cut along one 112 of the ribs. The artificial turf system 100 is installed on top of a base layer 110. The base layer can be, for example, stone, sand, concrete, wood, or any other type of material or material mixture.

[0083] FIG. 1B is another cross-sectional view of the artificial turf system 100 depicted in FIG. 1A that was cut at another position. The cross-sectional view depicts the cross-section of multiple ribs outside of a node region. The thin line 116 illustrates that the lower surface of the upper e-layer 104 and the upper surface of the lower e-layer 108 contact each other, thereby embedding and mechanically fixing the geogrid 106.

[0084] FIG. 2 is a schematic, cross-sectional view of a lower e-layer 108 comprising elastic granules 204 that are randomly distributed and embedded in a binder 202, e.g., a solidified PU reaction mixture. The elastic granules can be, for example, rubber granules, such as EPDM or SBR rubber granules.

[0085] According to some embodiments, the composition of the upper e-layer 104 (not shown in FIG. 2) is identical to the composition of the lower e-layer depicted in FIG. 2. According to other embodiments, the composition of the lower e-layer is different from the composition of the upper e-layer. For example, the lower e-layer 108 can comprise additional fillers, such as sand and/or chalk, that are absent in the upper e-layer or that are contained to a significantly lesser extent (e.g., at least 10% less by weight, or at least 20% less by weight) in the upper e-layer than in the lower e-layer. The additional fillers may reduce the costs of the material but increase the brittleness of the material, whereby an increased brittleness in the lower layer is more acceptable as already the upper elastic layer may largely absorb the shock of impacting objects.

[0086] FIG. 3 is a schematic, cross-sectional view of a lower e-layer 208 that comprises elastic granules 204 and fibers 306. The granules and fibers are randomly distributed and embedded in a binder 202.

[0087] FIG. 4 is a flowchart of a method of producing an artificial turf system 100, e.g., an artificial turf system as depicted in FIG. 1 or 5. The method described in the following is graphically illustrated in greater detail in FIG. 6.

[0088] First, in step 402, a lower e-layer 108 is placed on a base layer 110. The lower e-layer 108 can be created using an in-situ PU foam generation method as described, for example, in WO2018002203A1, EP3263620A1, or EP3216919A1. Alternatively, prefabricated, elastic PU tiles or lanes can be placed on the base layer 110 for providing the lower e-layer. Optionally, the lower e-layer can be glued, tacked, nailed, or otherwise fixed to the base.

[0089] Next, in step 404, a geogrid 106 is placed on the lower e-layer 108. Preferably, this step is performed after the lower e-layer has completely cured. In some embodiments, the geogrid may be applied while the in situ—generated lower e-layer is still liquid, such that some portions of the geogrid, e.g., the lower 2-4 mm of the geogrid, are embedded in the lower e-layer.

[0090] Next, in step 406, an upper e-layer 104 is placed on the geogrid. The upper e-layer can be applied, for example, in the form of a liquid PU reaction mass that embeds upper portions of the geogrid and contacts the surface of the lower e-layer where the lower e-layer is not covered by ribs or nodes of the geogrid. This may be advantageous, as the geogrid is fixed in between the two e-layers particularly firmly. This may prevent any relative movement of the geogrid and the e-layers without the need for an extra working step, e.g., without the need for applying an adhesive layer on top of the geogrid and the upper surface of the lower e-layer for ensuring that the geogrid and the upper e-layer do not change their position relative to each other.

[0091] Again, the upper e-layer 104 can be created using an in situ PU foam generation method as described, for example, in WO2018002203A1, EP3263620A1, or EP3216919A1.

[0092] Alternatively, prefabricated, elastic PU tiles or lanes can be placed on the geogrid for providing the upper e-layer. Optionally, the upper e-layer can be glued, tacked, nailed, or otherwise fixed on top of the geogrid.

[0093] Next, in step 408, an artificial turf layer 102 is placed on the upper e-layer. According to some embodiments, the artificial turf layer 102 is applied after the upper e-layer has hardened. If the e-layer is provided in the form of prefabricated tiles or lanes, the e-layer has already hardened at the production site. Applying the artificial turf on top of a hardened upper e-layer may ease the installation process, as the workers can freely walk over the upper e-layer. According to other embodiments, the artificial turf layer 102 is installed before the upper e-layer has completely cured. In this case, the liquid PU reaction mixture that is used for providing the upper e-layer may contact the lower side of the artificial turf layer. According to preferred embodiments, the artificial turf comprises a PU-based backing. This may be advantageous, as the backing and the upper e-layer both consist of urethane and may therefore have similar polarity. This may increase the fixation of the artificial turf layer on top of the upper e-layer.

[0094] FIG. 5 is a schematic, cross-sectional view of an artificial turf system 500 according to an exemplary embodiment of the invention. The artificial turf system 500 comprises an artificial turf layer 102 that is installed on top of an upper e-layer 104, a geogrid 106, and a lower e-layer 108, which are also part of the artificial turf system 500 and which have been described already with reference to FIG. 1. The artificial turf layer 102 comprises a plurality of artificial turf fibers 504, which are incorporated in a carrier structure, e.g. a carrier layer 118. The carrier layer can be, for example, a fiber mesh made of synthetic and/or plant-based fibers. The lower side of the carrier can be completely or partially covered by a backing 502, e.g., a latex-based or PU-based backing. The backing 502 incorporates at least some portions of the fibers 504, thereby firmly fixing the fibers in the carrier. The backing 502 is configured to fix a portion of the fibers, and may in addition have a cushioning effect from the forces transmitted and received from above by players or other activities occurring on the artificial turf system 500. In some embodiments, the carrier mesh 118 is formed by interwoven parts of the synthetic artificial turf fibers.

[0095] Optionally, the artificial turf layer 102 can comprise an infill layer 508. The infill layer comprises a plurality of infill granules 506, e.g., sand, organic granules, rubber granules, or mixtures thereof. The infill layer provides some extra elasticity. However, as the two e-layers already provide elastic support for the elastic turf, an artificial turf system 100, 500 is preferably free of an infill layer or comprises only a very thin infill layer, e.g., a layer of only 0.5 cm in height. This may reduce installation and maintenance costs, because the infill granules 506 may be blown away or may leave the artificial turf system as a result of the frequent use of the artificial turf system. In addition, it may be difficult or impossible to separate the infill from debris that may accumulate between the fibers over the years. To the contrary, the elastic granules or other elastic elements that constitute or are incorporated in the lower and/or upper e-layer cannot leave the e-layer or intermix with debris. Hence, using the two e-layers instead of an infill layer may reduce maintenance effort and may increase the life of the artificial turf system.

[0096] In one embodiment, the artificial turf fibers 504 are arranged in the carrier structure 118—e.g., a textile plane—by means of tufting. Tufting is a type of textile weaving in which an artificial turf fiber (which may be a monofilament or a bundle of multiple monofilaments) is inserted in or through the carrier structure 118. After the inserting is done, some parts of the artificial turf fibers 504, exposed to a lower side of the carrier structure 118, are mechanically fixed by the elastic backing 502. Other parts of the artificial turf fibers 504 are fixed by the carrier structure 118 and still further parts of the artificial turf fibers protrude from the upper surface of the carrier and form the visible artificial turf fibers.

[0097] In one embodiment, the backing 502 may be formed by applying an elastic binding agent—e.g., latex or a PU reaction mixture—onto the lower side of the carrier after the fibers are tufted or otherwise integrated into the carrier. The elastic binding agent can be any kind of fluid that is capable of solidifying after a predefined setting (or hardening) time into a solid layer or film. The fluid, also referred to as an elastic binding composition, may solidify into a film or layer by a drying process or by a chemical reaction resulting in a solidification of the fluid into a solid backing. Such a chemical reaction can be, for example, a polymerization.

[0098] FIG. 5 shows a large hole 510 in a base layer 110 that may have been created as the result of frequent freeze-thaw cycles. For example, several materials that are commonly used as a base layer, such as concrete or concrete-stone mixtures, may show significant signs of decay after several years of use, in particular in climate zones with frequent freeze-thaw cycles. The applicant has observed that some types of artificial turf layers that are directly installed on top of a base layer 110 may be damaged or even torn apart when a ball or the foot of a player hits the artificial turf layer just above such a hole 510. The absence of the base layer at the point of impact implies that the artificial turf layer has to absorb and withstand the impacting force on its own. This requires a mechanical strength that may not be supported by all types of artificial turf systems, in particular not by cheaper artificial turf variants. Using two e-layers and a geogrid may provide sufficient support to protect cheap, lightweight artificial turf variants from damage caused by objects that hit the artificial turf just above a hole in the base layer. This is because the impact is homogeneously distributed by the geogrid over a large surface area.

[0099] Preferably, embodiments of the artificial turf system 100, 500 have drainage holes or other means for providing effective drainage of water. They offer an effective manner of providing for a level playing surface, but also provide for a playing surface that has enough cushion to simulate real grass playing surfaces.

LIST OF REFERENCE NUMBERS

[0100] 100 artificial turf system [0101] 102 artificial turf layer [0102] 104 upper e-layer [0103] 106 geogrid [0104] 108 lower e-layer [0105] 110 base layer [0106] 112 rib of geogrid [0107] 114 node of geogrid [0108] 118 carrier structure [0109] 202 binder [0110] 204 elastic granules [0111] 306 fiber [0112] 402-408 steps [0113] 500 artificial turf system [0114] 502 backing [0115] 504 artificial turf fibers [0116] 506 infill granules [0117] 508 infill layer [0118] 510 hole in the base layer