Artificial turf field

Abstract

Artificial turf field, and related installation method, comprising:an artificial turf mat comprising a backing support and artificial fibres attached thereto, andan infill interspersed between the artificial fibres above the backing support, wherein the infill comprises:a first layer substantially made of one or more soft granular organic materials.a second layer above the first layer and substantially made of one or more hard granular inorganic materials anda third layer above the second layer and substantially made of one or more soft granular organic materials.

Description

TECHNICAL FIELD OF THE INVENTIONThe present invention relates to an artificial turf field, e.g. for sport use, having an infill.STATE OF THE ARTArtificial turf fields for sport use (e.g., fields for soccer, American football, rugby, baseball, etc.) are known.Typically, the artificial turf field comprises an artificial turf mat laid above a rigid and compact substrate, for example made of clay or asphalt, possibly with the interposition of a shock absorber pad and / or other functional layers.The artificial turf mat comprises a backing support and artificial fibres attached thereto, e.g. by way of tufting, to imitate natural grass.A granular material, called infill, is typically interspersed between the artificial fibres above the backing support. The infill structurally stabilizes the synthetic turf mat and / or improves its aesthetic quality, making it more similar to natural grass (since it helps keeping the artificial fibres upright), and / or facilitates its sport use, improving its performance properties.

[0006] The patents US2013243976A1, WO2024125947A1, US2024084523A1, WO2006109110A1, WO2007010324A1, US2018080183A1, WO2007077193A1, KR100919458B1, EP3868955A1, US2024159000A1, US2010055461A1, WO2020188609A1, WO2014049531A3, WO2011024066A2, WO2008125895A1, WO2021171172A1 and ITMI20131235A1 disclose artificial turf fields with an infill.SUMMARY OF THE INVENTION

[0007] The Applicant has faced the problem of providing an artificial turf field having an infill entirely made of natural material, i.e. inorganic and / or organic material, to the benefit of the environment and / or to facilitate the disposal of the infill at the end of its life cycle, while at the same time providing the desired characteristics of the field over time, in terms of mechanical performance (e.g. shock absorption, rolling / bouncing of the ball, safety, etc) and / or water retention.

[0008] One or more of the above problems are solved by an artificial turf field in accordance with the appended claims and / or having the following characteristics.

[0009] According to an aspect the invention relates to an artificial turf field comprising:

[0010] an artificial turf mat comprising a backing support and artificial fibres attached thereto, and

[0011] an infill interspersed between the artificial fibres above the backing support.

[0012] Preferably the infill comprises a first layer substantially made of one or more soft granular organic materials.

[0013] Preferably the infill comprises a second layer (directly) above the first layer and substantially made of one or more hard granular inorganic materials.

[0014] Preferably the infill comprises a third layer (directly) above the second layer and substantially made of one or more soft granular organic materials.

[0015] In one aspect the invention relates to a method for installing an artificial turf field.

[0016] The method comprises:

[0017] laying down an artificial turf mat comprising a backing support and artificial fibres attached thereto, and, subsequently,

[0018] interspersing an infill between the artificial fibres.

[0019] Preferably said interspersing comprises spreading above the artificial turf mat a first layer substantially made of one or more soft granular organic materials.

[0020] Preferably said interspersing comprises, subsequently, spreading a second layer (directly) above the first layer, said second layer being substantially made of one or more hard granular inorganic materials.

[0021] Preferably said interspersing comprises, subsequently, spreading a third layer (directly) above the second layer, said third layer being substantially made of one or more soft granular organic materials.

[0022] The term “organic” refers to any solid material involving organic life or created from or by organic life, in particular vegetables and animals.

[0023] The term “inorganic” refers to any solid material involving neither organic life nor the products created from or by organic life, such as minerals, glass, etc.

[0024] The term “granular” or the like refer to a flowable material consisting of small particles of any shape, e.g. rounded, oval, irregular, etc.

[0025] The relative terms “hard” and “soft” when used in combination mean that the soft material has a hardness lower than the hardness of the hard material, independently by the method used for measuring it.

[0026] A hardness scale according to the standard ASTM D2240 type A scale (“Shore A”) can be used to measure hardness. In this case, “soft” may possibly mean a Shore A hardness lower than or equal to 40, preferably lower than or equal to 35, more preferably lower than or equal to 30, and / or higher than or equal to 10, preferably higher than or equal to 15, more preferably higher than or equal to 20. Conversely, “hard” may possibly mean a Shore A hardness higher than or equal to 90, preferably higher than or equal to 95, more preferably equal to 100. As regards hard material, the standard ASTM D2240 type D scale (“Shore D”) can be used to measure hardness. In this case, “hard” may possibly mean a Shore D hardness higher than or equal to 70, preferably higher than or equal to 80, more preferably higher than or equal to 90, e.g. equal to 100.

[0027] The expression “layer substantially made of” means that at least 60% by volume, preferably at least 70% by volume, even more preferably at least 80% by volume, of the layer is made of the specified material(s).

[0028] The expression “layer essentially made of” means that at least 90% by volume, preferably at least 95% by volume, of the layer is made of the specified material(s).

[0029] The expression “layer entirely made of” means that at least 98% by volume, preferably at least 99% by volume, even more preferably 100% by volume, of the layer is made of the specified material(s).

[0030] The expressions “layer directly above or below another layer (or the backing support)” means that the two layers (or the pair layer / backing) are contactingly adjacent one to the other (i.e. no further layer / s or materials is / are interposed in between).

[0031] It is noted that when any given layer of infill (e.g. the first or third layer) comprises two or more different materials, such materials can be mixed together before spreading the layer or they can be spread separately in different layers one above the other (in the latter case a certain degree of intermixing may subsequently occur after use of the field).

[0032] It is also noted that in the multi-layer infill structure of the present invention the separation interface between two contactingly adjacent layers is physically clear cut immediately after the spreading of the layers, but thereafter it may become less clear due to a partial intermixing of the materials of the two layers following the use of the field and / or maintenance operations and / or rain falls.

[0033] The Applicant (without restricting to any theory) believes that the specific configuration wherein a layer of soft material (the first layer) is placed below a layer of hard material (the second layer) allows an effective distribution onto the first layer of the mechanical forces acting on top of the infill, at a greater extent with respect to a normal arrangement wherein the soft material layer (aimed at absorbing the mechanical shock) is placed above a hard material layer (aimed at stabilizing the artificial fibers). While in the normal arrangement the soft material layer may receive more directly any mechanical stress acting on the infill, in the arrangement of the present invention the soft material layer (the first layer) below the hard material layer (the second layer) may receive any mechanical shock less directly, since the shock is transferred by the hard material layer, which distribute the shock over a larger area of the first layer.

[0034] In this way the overall performance is improved, especially in terms of shock absorption and / or deformation characteristics.

[0035] The Applicant has surprisingly verified that the hard second layer contributes to anchor the deeper, softer first layer firmly to the artificial turf mat, substantially preventing the first layer from mixing with the other layers. The infill system may thus maintain its properties over time, with reduced movement and settlement post-installation of the different layers (however, some ongoing maintenance, e.g. via top-dressing, may still be required).

[0036] The Applicant has also found that the layer of soft material (the third layer) on top of the first and second layers allows to improve the safety of the turf field, since the third layer (the layer in contact with the users) softens the physical interaction between the users and the turf field.

[0037] The present invention can have one or more of the following preferred features.

[0038] Preferably a height of said artificial fibers is greater than or equal to 30 mm, more preferably greater than or equal to 50 mm, even more preferably greater than or equal to 60 mm, and / or less than or equal to 90 mm, more preferably less than or equal to 80 mm. In this way the artificial turf mimics the natural grass.

[0039] Preferably a total thickness of said infill is greater than or equal to 20 mm, more preferably greater than or equal to 30 mm, even more preferably greater than or equal to 40 mm, and / or less than or equal to 80 mm, more preferably less than or equal to 70 mm. In this way the artificial turf mimics the natural grass topsoil.

[0040] Preferably, said soft granular organic materials are selected in the following group: cork, olive pits, corn cobs, rice husks, nut shells (e.g., walnut, almond, pecan), coconut husks, wood fibers, peat moss, bamboo fibers, leather, soybean hulls, sunflower seed shells, flax seeds, and hemp shives.

[0041] Preferably said first layer is substantially, or essentially, or entirely, made of cork and / or coconut husks, even more preferably of cork.

[0042] Preferably a total thickness of said first layer is greater than or equal to 10 mm, more preferably greater than or equal to 15 mm, and / or less than or equal to 30 mm, more preferably less than or equal to 20 mm.

[0043] The Applicant has verified that a first layer made of these materials, in particular cork, and / or having the above thicknesses, provides optimal cushioning, load absorption and mimics the softer soil in natural grass systems.

[0044] Preferably, said hard granular inorganic materials are selected in the following group: sand (e.g. silica sand, quartz sand, and / or coloured sand), calcium carbonate, zeolites, volcanic ash, perlite, clay minerals, crushed stone, recycled glass granules, diatomaceous earth, mica flakes.

[0045] Preferably said second layer is substantially, or essentially, or entirely, made of sand.

[0046] Preferably a total thickness of said second layer is greater than or equal to 20 mm, more preferably greater than or equal to 25 mm, and / or less than or equal to 40 mm, more preferably less than or equal to 35 mm.

[0047] Preferably said second layer consists of a first sub-layer and a second sub-layer directly (i.e. in contact with the first sub-layer) on top of the first sub-layer.

[0048] Preferably a thickness of each of said first and / or second sub-layer is greater than or equal to 10 mm, more preferably greater than or equal to 15 mm, and / or less than or equal to 20 mm.

[0049] Preferably said first sub-layer is substantially, or essentially, or entirely, made of sand having granulometric size comprised between 0.2 mm to 1.0 mm.

[0050] Preferably said second sub-layer is substantially, or essentially, or entirely, made of sand having granulometric size comprised between 1.0 mm to 1.6 mm.

[0051] The Applicant has verified that a second layer made of sand and / or having the above structure and / or thicknesses, provides optimal structural support and stability (limiting in particular the movement of the underlaying material) and porosity.

[0052] Preferably said third layer is substantially, or essentially, or entirely, made of cork and / or coconut husks and / or olive pits, even more preferably of cork and / or olive pits, e.g. a mixture of cork and olive pits.

[0053] Preferably said third layer contains more than 30%, preferably more than 40%, in volume of cork, and more than 30%, preferably more than 40%, in volume of olive pits.

[0054] Preferably a total thickness of said third layer is greater than or equal to 5 mm, more preferably greater than or equal to 10 mm, and / or less than or equal to 20 mm, more preferably less than or equal to 15 mm.

[0055] The Applicant has verified that a third layer made of these materials and / or having the above thicknesses, provides optimal field interaction and enhances player comfort, stud penetration for grip, and / or ball behaviour.

[0056] In one embodiment the first layer is directly above the backing support (i.e. the first layer is the bottom layer of the whole infill).

[0057] In one embodiment the infill may comprise a fourth layer (preferably directly) below the first layer, preferably directly above the backing support, substantially made of one or more hard granular inorganic materials. Preferably said fourth layer is substantially, or essentially, or entirely, made of sand. Preferably a total thickness of said fourth layer is greater than or equal to 5 mm, and / or less than or equal to 15 mm, more preferably less than or equal to 10 mm.

[0058] The fourth layer raises the artificial fibers, thus facilitating to fill in the soft material / s of the first layer, which are typically made of large and low-density granules.

[0059] In one embodiment said first and / or third layer may comprise a quantity (e.g. more than 5% and / or less than 40% or 30% in volume) of one or more fibrous materials, more preferably selected in the group: coir from coconut fibers, cotton fibers, jute, hemp, flax, sisal, leather and kenaf. Said one or more fibrous materials may contribute to stabilize the infill, limiting the movement of the various materials and / or the intermixing of the different layers.BRIEF DESCRIPTION OF THE FIGURE

[0060] FIG. 1 schematically shows a vertical cross-sectional view of the artificial turf field according to an embodiment of the present invention.DETAILED DESCRIPTION OF SOME EMBODIMENTS OF THE INVENTION

[0061] The features and the advantages of the present invention will be further apparent from the following detailed description of some embodiments, presented by way of non-limiting example of the present invention, with reference to the attached figure.

[0062] In the figure, the reference number 1 refers to an artificial turf field in accordance with the present invention.

[0063] The artificial turf field 1 (shown only schematically) comprises an artificial turf mat 2 laid above a rigid substrate 3, for example made of clay or asphalt or an artificial structure made of crates. Optionally, a shock absorber pad 4 and / or other functional layers can be interposed between the substrate 3 and the mat 2.

[0064] The artificial turf mat 2 comprises a backing support 5, such as a woven fabric (e.g., polyester, PP, or glassfibre), and artificial fibres 6 attached thereto (e.g. by tufting) to mimic the natural grass. The artificial turf mat 2 may comprise a secondary backing (not shown), such as a latex or polyurethane coating, on a downward face of the backing to fix the fibers to the backing support to ensure adequate pull-out resistance to the fibers.

[0065] The artificial turf field comprises an infill 7 interspersed between the artificial fibres above the backing support.

[0066] In the exemplary embodiment, the height H of the artificial fibers (considering the portion protruding from the backing support 5 as shown by the double arrow in FIG. 1) is equal to about 65 mm.

[0067] The infill 7 comprises:

[0068] a first layer 8 entirely made of cork granules (Shore A hardness equal to 20) and having a thickness of about 15 mm.

[0069] a second layer 9 directly above the first layer 8 and entirely made of sand (Shore A hardness equal to 100) and having a total thickness of about 30 mm; and

[0070] a third layer 10 directly above the second layer 9 and entirely made of a mixture of about 50% in volume of cork granules and about 50% in volume of olive pit granules (Shore A hardness equal to 25), and having a total thickness of about 10 mm.

[0071] Alternatively, the third layer 10 may consist, at least upon installation, of a first sub-layer, 5 mm thick, entirely made of cork granules and, directly above the latter, a second sub-layer, 5 mm thick, entirely made of olive pit granules.

[0072] Exemplarily the second layer 9 consists of a first sub-layer 9′ and a second sub-layer 9″ directly on top of the first sub-layer 9′ (the figure shows a dashed separation line between the two sub-layers).

[0073] Exemplarily a thickness of each sub-layer of the second layer 9 is equal to 15 mm.

[0074] Exemplarily the first sub-layer 9′ is entirely made of sand having granulometric size comprised between 0.2 mm to 1.0 mm and the second sub-layer is entirely made of sand having granulometric size comprised between 1.0 mm to 1.6 mm.

[0075] Exemplarily the infill 7 comprises a fourth layer 11 directly below the first layer 8 and directly above the backing support 5 entirely made of sand and having a thickness of about 5 mm.

[0076] The total thickness of the infill 7 is about 60 mm.

[0077] The Applicant has experimentally verified that such an artificial turf field, after simulated wear test, shows satisfactory stability of the cork layer 8, which remains in position, locked in place by the upper layer 9, in particular by its sub-layer 9′ of fine sand.

[0078] Performance tests conducted by the Applicant show minimal variation compared to the unworn turf field, that demonstrate the efficiency of the soft layer 8.

Claims

1. Artificial turf field comprising:an artificial turf mat comprising a backing support and artificial fibres attached thereto, andan infill interspersed between the artificial fibres above the backing support, wherein the infill comprises:a first layer substantially made of one or more soft granular organic materials.a second layer above the first layer and substantially made of one or more hard granular inorganic materials anda third layer above the second layer and substantially made of one or more soft granular organic materials.

2. The field according to claim 1, wherein said second layer is directly above the first layer and said third layer is directly above the second layer.

3. The field according to claim 1, wherein said one or more soft granular organic materials have a Shore A hardness lower than or equal to 40 and / or higher than or equal to 10 and said one or more hard granular inorganic materials have a Shore A hardness higher than or equal to 90.

4. The field according to claim 1, wherein said first layer is essentially or entirely made of said one or more soft granular organic materials, said second layer is essentially or entirely made of said one or more hard granular inorganic materials and said third layer is essentially or entirely made of said one or more soft granular organic materials.

5. The field according to claim 1, wherein said soft granular organic materials are selected in the following group: cork, olive pits, corn cobs, rice husks, nut shells, coconut husks, wood fibers, peat moss, bamboo fibers, leather, soybean hulls, sunflower seed shells, flax seeds, and hemp shives.

6. The field according to claim 1, wherein said first layer is essentially or entirely made of cork.

7. The field according to claim 1, wherein a total thickness of said first layer is greater than or equal to 10 mm, and / or less than or equal to 30 mm.

8. The field according to claim 1, wherein said hard granular inorganic materials are selected in the following group: sand, calcium carbonate, zeolites, volcanic ash, perlite, clay minerals, crushed stone, recycled glass granules, diatomaceous earth, mica flakes and wherein a total thickness of said second layer is greater than or equal to 20 mm, and / or less than or equal to 40 mm.

9. The field according to claim 1, wherein said second layer is essentially or entirely made of sand.

10. The field according to claim 1, wherein said second layer consists of a first sub-layer and a second sub-layer directly on top of the first sub-layer, wherein a thickness of each of said first and / or second sub-layer is greater than or equal to 10 mm, and / or less than or equal to 20 mm, wherein said first sub-layer is substantially or essentially or entirely made of sand having granulometric size comprised between 0.2 mm to 1.0 mm and wherein said second sub-layer is substantially or essentially or entirely made of sand having granulometric size comprised between 1.0 mm to 1.6 mm.

11. The field according to claim 1, wherein said third layer is substantially or essentially or entirely made of cork and / or coconut husks and / or olive pits.

12. The field according to claim 1, wherein said third layer contains more than 30% in volume of cork, and more than 30% in volume of olive pits.

13. The field according to claim 1, wherein a total thickness of said third layer is greater than or equal to 5 mm and / or less than or equal to 20 mm.

14. The field according to claim 1, wherein the infill comprises a fourth layer below the first layer and directly above the backing support, the fourth layer being substantially or essentially or entirely made of sand and having a total thickness greater than or equal to 5 mm and less than or equal to 15 mm.

15. Method for installing an artificial turf field, the method comprising:laying down an artificial turf mat comprising a backing support and artificial fibres attached thereto, and, subsequently,interspersing an infill between the artificial fibres,wherein said interspersing comprises:spreading above the artificial turf mat a first layer substantially made of one or more soft granular organic materials;subsequently, spreading a second layer above the first layer, said second layer being substantially made of one or more hard granular inorganic materials: andsubsequently, spreading a third layer above the second layer, said third layer being substantially made of one or more soft granular organic materials.

Images