WO2018087668A1

WO2018087668A1 - Artificial turf with water retaining base

Info

Publication number: WO2018087668A1
Application number: PCT/IB2017/056977
Authority: WO
Inventors: John Penninck
Original assignee: Sports And Leisure Group Nv
Priority date: 2016-11-09
Filing date: 2017-11-08
Publication date: 2018-05-17
Also published as: BE1024290B1; EP3538712A1

Abstract

The present invention relates to an artificial turf mat that Is appropriate for sports fields, comprising: (i) a backing provided with a plurality of artificial turf fibres, and (ii) a water-retaining base layer provided between said artificial turf fibres. The artificial turf mat according to the invention offers Improved water characteristics and a constant elasticity.

Description

ARTIFICIAL TURF WITH WATER RETAINING BASE

TECHNICAL FIELD The present invention relates to artificial turf mats for sports purposes, such as football and hockey. In particular, the invention relates to an artificial turf with improved water characteristics and a constant elasticity.

BACKGROUND

Artificial turfs are usually provided as mats of polyethylene or propylene fibres with a pile height of 10 to 60 mm, in which filling as reinforcing element is applied to the mat to keep the polyethylene or polypropylene fibres in an upright position. The filling can be composed of sand and/or granular rubber grains.

In order to avoid difficulties when uniformly applying the sand and the granular rubber grains over a sports field, systems have been developed in which such reinforcing elements are integrated in the artificial turf mat. For example, NL 105451 discloses, an artificial turf appropriate for sports fields, composed of a carrier, onto which artificial turf fibres have first been applied. The artificial turf is further processed as a result of which a material with damping characteristics is present onto and/or into the mat to approach the characteristics of a natural grass field.

WO 2016/024044 discloses artificial turfs with artificial turf fibres into which rubber- coated monofilament base fibres have been processed to provide a sufficient strength and elasticity. In this way, the artificial turf fibres stay in a vertical position without having to add a granular sowing material.

For certain sports, water is applied to the filed before a competition. Such fields are developed in a specific way and are referred to by the term 'water field'. For use as a playing field, it is important that a layer of water has first been applied. The most important advantages of a water field are the speed and the consistent rolling of the ball. Moreover, burns when falling and sliding onto this ground also belong to the past. For this reason, the use of a water field is also appropriate in other sports, especially contact sports such as football, rugby, etc. An important shortcoming of the present water fields is however that the amount of water on the field significantly decreases after about 10 min., as a result of which the playing characteristics of the field do not remain constant. In water fields according to the state of the art, the origin of a falling ball will for example already exceed the test threshold of 40 cm after 15 min. Therefore, the playing field will have to be sprayed several times during a competition. Also, at a decreasing amount of water on the field, the ball speed also decreases, reducing the playing quality.

The present invention aims to offer a solution for one or more of the said problems or defects.

SUMMARY

Thereto, the invention offers an artificial turf mat according to claim 1.

In a first aspect, the invention provides an artificial turf mat that is appropriate for sports fields, comprising : (i) a back layer provided with a multitude of artificial turf fibres, and (ii) a water-retaining base layer provided between said artificial turf fibres.

This has the advantage that (i) the field is much more appropriate for retaining water, as a result of which the playing and ball characteristics remain constant for a longer period; (ii) the water consumption of a water field with the artificial turf mat according to the invention is considerably reduced; (iii) the field characteristics of the complete playing field are kept constant within predefined limits; and (iv) the field allows for high-quality technical characteristics, a maximum manoeuvrability, an excellent playing comfort and ball speed.

In a second aspect, the present invention provides for a method for producing an artificial turf mat, comprising the steps:

- providing a plurality of artificial turf fibres at a first side of a ground cloth;

- providing a water-retaining base layer at said first side of said ground cloth; and - coating a second side of said ground cloth, opposite to said first side. In a third aspect, the invention provides for a use of an artificial turf mat according to the first aspect of the invention, in which water is applied to said artificial turf mat. DESCRIPTION OF THE FIGURES

The explicit characteristics, advantages and objectives of the present invention will become clear for the skilled worker in the technical domain of the invention from the following detailed description of the embodiment of the invention and the attached figures. The figures are only illustrative of the invention, and are in no case limitative of the invention.

Figure 1 to 3 illustrate a simplified view of an artificial turf mat according to the invention and of its ball and water characteristics.

Figure 1 is a schematic view of an artificial turf mat according to the present invention.

Figure 2 is a schematic view of the height of the ball bounce in time, in which Figure 2A is an illustration of an artificial turf mat according- to the state of the art, and in which Figure 2B is an illustration of an artificial turf mat according to the invention.

Figure 3 is a schematic view of the height of the moisture content in time, in which Figure 3A is an illustration of an artificial turf mat according to the state of the art, and in which Figure 3B is an illustration of an artificial turf mat according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

Unless otherwise specified, all terms used in the description of the invention, including technical and scientific terms, shall have the meaning as they are generally understood by the worker in the technical field of the invention. For a better understanding of the description of the invention, the following terms are explained specifically. "A", "an" and "the" refer in the document to both the singular and the plural form unless clearly understood differently in the context. "A segment" means for example one or more than one segment. When "approximately" or "about" are used in the document together with a measurable quantity, a parameter, a period or moment, etc., variations of +/-20% or less, preferably +/-10% or less, more preferably +/-5% or less, still more preferably or less, and even still more preferably +/-0.1% or less than and of the cited value are meant, as far as such variations apply to the invention that is described. It will however be clearly understood that the value of the quantity at which the term "approximately" or "about" is used, is itself specified.

The terms "include", "including", "consist", "consisting", "provide with", "contain", "containing", "comprise", "comprising" are synonyms and are inclusive of open terms that indicate the presence of what follows, and that do not exclude or prevent the presence of other components, characteristics, elements, members, steps, known from or described in the state of the art.

The citation of numeric intervals by means of end points includes all integers, fractions and/or real numbers between the end points, including these end points.

In a first aspect, the invention provides an artificial turf mat that is appropriate for sports fields, comprising : (i) a back layer provided with a multitude of artificial turf fibres, and (ii) a water-retaining base layer provided between said artificial turf fibres. Preferably, said water-retaining base layer is comprised of multifilament fibres. In an alternative embodiment, said water-retaining base layer can be comprised of another water-retaining, elastic material, such as a foam or a spongy material. A first advantage is that, contrary to sand, granular rubber or monofilament fibres, the multifilament fibres are much more appropriate for retaining water. The multifilament fibres form capillary spaces in which the water can be retained much better. In this way, the water field can regulate its moisture content autonomously. Irrespective of the weather conditions, the moisture content remains optimal during the entire length of a competition, namely at least one hour. A second advantage of the invention is that the multifilament fibres offer enough volume for supporting the artificial turf fibres. In this way, adding a filling material such as sand and/or rubber granulate is no longer necessary. Because the multifilament fibres are inserted between the artificial turf fibres during the production of the artificial turf mat, a uniform distribution of the multifilament fibres can be carried out much more accurately. In this way, the field characteristics can be kept constant within predefined limits over the complete playing field.

A third advantage is that a water field with the artificial turf mat according to the invention allows for high-quality technical playing characteristics, a maximum manoeuvrability and an excellent playing comfort. Moreover, the speed of the ball on a water field is further improved.

A fourth advantage is that the playing field must be sprayed must less, as a result of which the water consumption is reduced considerably. Test results show that the water consumption decreases at least 50%, and experience data show that a water saving up to 70% is realized.

In a preferred embodiment, the present invention provides for an artificial turf mat according to the first aspect of the invention, in which said multifilament fibres are provided with a density of at least 1,000,000 multifilament fibres per square meter. The density of multifilament fibres, expressed per square meter, can be calculated by multiplying the number of tufts per square meter, as determined according to IS01763, by the number of filaments per tuft. The density of multifilament fibres should then be determined as the average of 20 tufts out of an artificial turf mat of 200 mm x 200 mm. Preferably, said artificial turf mat is provided with a density of at least 2,500,000 multifilament fibres per square meter and more preferably of 2,500,000 to 25,000,000 multifilament fibres per square meter. Still more preferably, said artificial turf mat is provided with a density of 3,000,000 multifilament fibres per square meter to 30,000,000 multifilament fibres per square meter, and still more preferably with a density of 4,000,000 multifilament fibres per square meter to 20,000,000 multifilament fibres per square meter, or even with a density of 5,000,000 multifilament fibres per square meter to 15,000,000 multifilament fibres per square meter. More preferably, said artificial turf mat is provided with a density of 6,000,000, 7,000,000, 8,000,000, 9,000,000, 10,000,000, 11,000,000, 12,000,000, 13,000,000, 14,000,000, 15,000,000, 16,000,000, 17,000,000 or 18,000,000 multifilament fibres per square meter, or any value in between. In this way, an advantageous optimum has been found between water-retaining characteristics on the one hand and elasticity on the other hand. Moreover, it seems that at higher densities, the sliding characteristics of the artificial turf mat deteriorate, and at predefined densities, no unnecessary amounts of material are used for production.

In conjunction with an optimal density of the multifilament fibres as described above, the present invention provides for an artificial turf mat according to the first aspect of the invention, in which said multifilament fibres are provided with a linear weight of 1 to 100 dtex per filament. Preferably, said multifilament fibres are provided with a weight of 5 to 50 dtex, and more preferably 10 to 30 dtex per filament and most preferably 15 to 30 dtex per filament. A sufficiently thin thickness of the multifilament fibres allows to provide a larger amount of multifilament fibres in the artificial turf mat as well as to provide a larger specific surface, as a result of which better water-retaining characteristics are obtained. In a preferred embodiment, said monofilament fibres comprise fibrillated yarns. Fibrillated yarns are produced in the form of a band with a width of 10 to 15 mm, followed by incision thereof (fibrillation). Preferably, the weight of the fibrillated yarns is situated between 500 and 5,000 dtex, and more preferably between 800 and 2.000 dtex and most preferably equal to 1,000, 1,250, 1,500, 1,750, 2,000, 2,500, 2,750, or 3,000 dtex, or any value in between. In a preferred embodiment, said multifilament fibres comprise BCF (bulked continuous filaments) yarns. Preferably, the weight of the BCF yarns is situated between 500 and 5,000 dtex, and more preferably between 500 and 1,500 dtex and most preferably equal to 800, 900, 1,000, 1,100, 1,200, 1,300, 1,400, or 1,500 dtex, or any value in between. Still more preferably, said BCF yarns is comprised of. Dtex is a measure for linear mass density of fibres and is defined as the weight in gram per 10,000 meters. In a preferred embodiment, the present invention provides for an artificial turf mat according to the first aspect of the invention, in which said water-retaining water base layer is provided with a specific surface weight of 50 gsm to 500 gsm, determined according to ISO 8543. More preferably,. said water-retaining base layer is provided with a specific surface weight of 150 gsm to 350 gsm. Most preferably, said water-retaining base layer is provided with a specific surface weight of 150 gsm, 175 gsm, 200 gsm, 225 gsm, 250 gsm, 275 gsm, 300 gsm, 325 gsm or 350 gsm, or any value in between. This offers the advantage that a sufficiently high density is obtained to provide for good water-retaining characteristics. When the density of the water-retaining layer become too high, the artificial turf mat however becomes to slippery which is detrimental for good sporting characteristics of the artificial turf mat.

In a preferred embodiment, the present invention provides for an artificial turf mat according to the first aspect of the invention, in which said multifilament fibres are connected to said back layer, preferably by means of tufts. This offers an improved solidity to the artificial turf mat so that the multifilament fibres do not come loose from the artificial turf mat after a while and the field characteristics can be retained. In one embodiment, the pool yarns are attached by tufting.

In a preferred embodiment, the present invention provides for an artificial turf mat according to the first aspect of the invention, in which the multifilament fibres of the water-retaining base layer are twined with the monofilament fibres representing the artificial turf fibres. This is advantageous because the monofilament fibres can thus be kept more easily in the upright position.

In a preferred embodiment, the present invention provides for an artificial turf mat according to the first aspect of the invention, in which said multifilament fibres are provided with a non-circular section. Such sections are more appropriate for retaining water in the water- retaining base layer. More preferably, said multifilament fibres are provided with a trilobal section. In a preferred embodiment, the present invention provides for an artificial turf mat according to the first aspect of the inventio, in which said multifilament fibres are provided with a tensile strength of at least 10 N per multifilament yarn and preferably equal to 20, 25, 30, 35, 40, 50, 75, 100, 125 or 150 N per multifilament yarn, or any value in between. As a result, the fibres are more resistant to damage.

In a preferred embodiment, the present invention provides for an artificial turf mat according to the first aspect of the invention, in which said multifilament fibres are provided in at least 5 filaments per fibre, more preferably at least 25 filaments per. fibre and still more preferably at least 50 filaments per fibre. Most preferably, said multifilament fibres comprise 75, 100, 125, 150, 175 or 200 filaments per fibre. This offers the advantage that more and finer capillary spaces are created in the multifilament fibres, as a result of which improved water-retaining characteristics are obtained.

In a preferred embodiment, the present invention provides for an artificial turf mat according to the first aspect of the present invention, in which said multifilament fibres are straight or curled. This offers the advantage that the layer of multifilament fibres becomes bulkier and shows better elasticity characteristics. Also, water is better retained in a layer with curled multifilament fibres. In a preferred embodiment, the present invention provides for an artificial turf mat according to the first aspect of the invention, in which said monofilament fibres are textured.

In a preferred embodiment, the present invention provides for an artificial turf mat according to the first aspect of the invention, in which said multifilament fibres are twined. Twined multifilament fibres have a higher tensile strength compared to non-twined multifilament fibres, and thus ensure a better retainability of the field characteristics. Moreover, twined multifilament fibres can be processed more easily when tufting. In a preferred embodiment, the present invention provides for an artificial turf mat according to the first aspect of the invention, in which said multifilament fibres are made of polyethylene, polypropylene, ethylene-propylene copolymer, polyamide, polyester, polyurethane or a blend of one or more of said polymers. Preferably, said multifilament fibres are made of a polymer with hydrophilic characteristics such as polyamide, polyester, polyurethane or a blend thereof. Still more preferably, said multifilament fibres are made of polyamide, preferably polyamide-6, polyamide-6,6 or polyamide-12. Next to water-retaining characteristics, polyamide also shows a high strength, as a result of which the fibres are more resistant to damage. Moreover, polymers with hydrophilic characteristics offer a better anchoring in a latex which can be applied as a back layer. Thus, a pool anchoring of more than 25 N, more than 30 N, and even more than 35 N can be obtained.

In a preferred embodiment, the present invention provides for an artificial turf mat according to the first aspect of the invention, in which said multifilament fibres form' a layer with a height P_w of 2 to 50 mm, determined according to ISO 2549. Preferably, said multifilament fibres form a layer with a height P_w of 5 to 30 mm and more preferably of 10 to 20 mm. Most preferably, said layer of multifilament fibres is provided with a height P_w of 10 mm, 11 mm, 12 mm, 13 mm or 14 mm, or any value in between.

In a preferred embodiment, the present invention provides for an artificial turf mat according to the first aspect of the invention, in which said monofilament fibres are provided with a tensile strength of at least 50 N and preferably equal to 60 N, 70 N, 80 N, 90 N, 100 N, 110 N, 120 N, 130 N, 140 N or 150 N, or any value in between. As a result, the fibres are better resistant to damage. In a preferred embodiment, the present invention provides for an artificial tuft mat according to the first aspect of the invention, in which said monofilament fibres are provided with a thickness of 50 to 200 pm. Preferably, said monofilament fibres are provided with a thickness of 75 to 150 pm, and more preferably with a thickness of 80, 90, 100, 110, 120, 130 or 140 pm. The artificial turf fibres can be composed of both monofilament, multifilament yarns as well as fibrillated yarns. In a preferred embodiment, the present invention provides for an artificial turf mat according to the first aspect of the invention, in which said artificial turf fibres are composed of monofilament fibres. Preferably, said monofilament fibres are provided with a thickness varying between 1,000 and 15,000 dtex, and preferably between 3,000 and 10,000 dtex, and still more preferably between 5,000 and 9,000 dtex. Most preferably, the thickness of said monofilament fibres is equal to 6,000, 6,500, 7,000, 7,500 or 8,000 dtex, or any value in between. In a preferred embodiment, the present invention provides for an artificial turf mat according to the first aspect of the invention, in which said artificial turf mat is made of polyethylene, polypropylene, ethylene-propylene copolymer, polyamide, polyester, polyurethane or a blend of one or more of said polymers. Preferably, said monofilament fibres are made of a polymer with hydrophilic characteristics such as polyamide, polyester, polyurethane or a blend thereof. Still more preferably, said monofilament fibres are made of polyamide, preferably polyamide-6, polyamide-6,6 or polyamide-12. Next to hydrophilic, water-retaining characteristics, polyamide also shows a high strength, as a result of which the fibres are better resistant to damage.

Preferably, said monofilament fibres are tufted in a textile layer in the back layer. In one embodiment, said monofilament, the gauge of the tufting machine is 3/16" (4.67 mm) and the number of stiches per row is 15 to 50 per 10 cm. The gauge of the tufting machine is a measure for the distance between the tufting needles. In one embodiment, the thickness of the tufting machine is 5/32 " (3.97 mm) and the number of stiches per row is 15 to 50 per 10 cm. In one embodiment, the gauge of the tufting machine is 5/16" (7.9 mm) and the number of stitches per row is 10 to 50 per 10 cm. In one embodiment, the gauge of the tufting machine is 5/8" (15.8 mm) and the number of stitches per row is 10 to 50 per 10 cm. In one embodiment, the gauge of the tufting machine is 3/8" (9.53 mm) and the number of stitches per row is 10 to 50 per 10 cm. In one embodiment, the gauge of the tufting machine is 3/4" (19.6 mm) and the number of stitches per row is 10 to 50 per 10 cm. The gauge of the tufting machine refers to the number of needles per inch and corresponds to the number of stitches per inch in one direction perpendicular to rows. The number of stitches per row is influenced by the size of the needles in the stitching machine and the thickness of the yarns. In one embodiment, the pool yarns are woven and the distance between successive pool yarns on row is 1 to 10 mm and the distance between adjacent rows is 1 to 10 mm. In one embodiment, the pool yarns are attached by means of Matrix weaving and the difference between successive pool yarn bundles in the direction of the rows is 5 to 20 mm and the interspace between adjacent pool yarn bundles in the direction perpendicular to rows is 5 to 20 mm. In one embodiment, the pool yarns are attached by tufting and the distance between successive pool yarns per row is 3 to 15 mm and the interspace between adjacent rows is 3 to 25 mm. In one embodiment, the pool yarns are attached by Matrix tufting and the distance between successive pool yarn bundles in the direction of the rows is 5 to 15 mm and the interval between adjacent pool yarn bundles in the direction perpendicular to rows is 5 to 20 mm.

In a preferred embodiment, the present invention provides for an artificial turf mat according to the first aspect of the invention, in which monofilament fibres are provided with a height P situated between 5 and 100 mm, determined according to ISO 2549, preferably between 10 and 75 mm. Preferably, said monofilament fibres form a layer with a height P_K of 5 to 30 mm and more preferably of 10 to 20 mm. Most preferably, said layer of monofilament fibres are provided with a height P_K of 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm or 16 mm, or any value in between. In a preferred embodiment, the present invention provides for an artificial turf mat according to the first aspect of the invention, in which said artificial turf mat has a pool weight of 500 to 3.000 gsm, determined according to ISO 8543, preferably of 1,000 to 2,500 gsm, and more preferably of 1,500 to 2,000 gsm.

In a preferred embodiment, the present invention provides for an artificial turf mat according to the first aspect of the invention, in which said back layer is made of a ground cloth and a coating. Preferably, said ground cloth is made of polypropylene with a weight of 100 to 500 gsm. Still preferably, said ground cloth is a tuft cloth or a tissue. Preferably, said ground cloth is fibre- reinforced, preferably with glass fibres. This allows to meet the high mechanical requirements on the artificial turf mat. This is especially desired in a hockey field. Preferably, said coating is a latex coating with a weight of 500 to 2.000 gsm, more preferably of 1.000 to 1.500 gsm. Preferably, said latex comprises a carboxylated styrene-butadiene latex with chalk filling, dispersing means, antioxidants, antibacteria, colouring and thickening means. In an alternative embodiment, said coating is comprised as a polyolefin hotmelt coating, an ethyl vinyl acetate (EVA) dispersion or a polyurethane coating.

In a preferred embodiment, the present invention provides for an artificial turf mat according to the first aspect of the invention, in which said back layer is permeable. Preferably, the artificial turf mat has a permeability of 1,10^"4 to 10, 10^"4 m/s, determined according to EN 12616, more preferably of 3,10^"4 to 8,10^"4 m/s, and most preferably of 5,10^"4 m/s, 6,10^"4 m/s or 7,10^"4 m/s. In a preferred embodiment, the present invention provides for an artificial turf mat according to the first aspect of the invention, in which said artificial turf mat has a weight of 1,500 to 10,000 gsm, as determined according to ISO 8543, preferably 2,500 to 5,000 gsm, and more preferably 3,000 to 3,500 gsm. In a preferred embodiment, the present invention provides for an artificial turf mat according to the first aspect of the invention, in which said artificial turf mat is free of granular filling material. By using multifilament fibres in the artificial turf mat, no further filling material is needed. This ensures more uniform characteristics of the playing field.

In a second aspect, the present invention provides for a method for producing an artificial turf mat, comprising the steps: - providing a plurality of artificial turf fibres at a first side of a ground cloth;

- providing a water-retaining base layer at said first side of said ground cloth; and

- coating a second side of said ground cloth, opposite to said first side. In a preferred embodiment, the present invention provides for a method according to the second aspect of the invention, in which said water-retaining base layer is composed of multifilament fibres.

In a preferred embodiment, the present invention provides for a method according to the second aspect of the invention, in which said multifilament fibres at said first side of said ground cloth have a density of at least 1,000,000 multifilament fibres per square meter.

In a preferred embodiment, the present invention provides for a method, in which the artificial turf mat according to the first aspect of the invention is produced by means of tri-dimensional or 3D weaving.

In a third aspect, the invention provides for a use of an artificial turf mat according to the first aspect of the invention, in which water is applied to said artificial turf mat. Preferably, at least 1 litre of water per square meter is applied to said artificial turf mat. This corresponds to a height of the water layer of at least 1 mm. Preferably, 3 to 5 litres of water per square meter is applied to said artificial turf mat, as a result of which a water layer with a height of 3 to 5 mm is obtained. EXAMPLE

The invention will now be further illustrated by means of the following example, without however being limited thereto. A UV-stable polypropylene tuft cloth 21 with glass fibre of 300 gsm is provided as a base cloth or ground cloth 21 and is tufted with 7,000 dtex polyamide monofilament fibres 3a, 3b, 3c, 3d, 3e and 1.350 dtex polyamide multifilament fibres 4a, 4b, 4c, 4d with 84 filaments per fibre made of trilobal BCF yarn. The monofilament fibres are provided with a tensile strength of 116 N and tear strength of 130%. The multifilament fibres are provided with a tensile strength of 33 N and tear strength of 78%. The ground cloth is linearly tufted with a gauge of 3/16", 380 stitches per meter, 79.800 tufts per m², and 15.002.400 filaments per m². The pool height P is 13 mm and the pool weight is 1,750 gsm. At the lower side of the ground cloth, a carboxylated styrene-butadiene latex is applied and set, as a result of which a latex layer 22 of 1,200 gsm is obtained . The ground cloth 21 and the latex layer 22 together form the back layer or backing 2 of the artificial turf mat 1. The pool anchoring of polyamide mono- and multifilament fibres in the set styrene- butadiene latex is determined as 38 N.

This has been schematically shown in Figure 1. Figure 1A shows a glass fibre- reinforced ground cloth 21 in which monofilament fibres 3 and multifilament fibres 4 are tufted with the pool at the same side of the tuft cloth 21. The monofilament fibres 3 and multifilament fibres 4 are provided with different pool heights, respectively P_K and P_w. In this way, the multifilament fibres 4 form a bulky filling between the monofilament fibres 3. In this way, the monofilament fibres 3 are kept in an upright position and protrude out of the bul ky filling to show the grass effect. The bulky filling provides for the water-regulating characteristics of the artificial turf mat according to the invention. Figure IB shows a preferred embodiment, in which the multifilament fibres 4 are twined with the monofilament fibres 3.

The field characteristics of the artificial turf mat have been tested and the results have been shown in Figure 2 and 3. Figure 2 is a schematic view of the height of the ball bounce in time, in which Figure 2A is an illustration of an artificial turf mat according to the state of the art, and in which Figure 2B is an illustration of an artificial turf mat according to the invention. The tests have been carried out in accordance to EN 12235. The results show that the ball bounce (expressed in meter, Y-axis) at a water field with artificial mat according to the invention for 1 hour (expressed in minutes, X-axis) remains under the FIH threshold, see Figure 2B. A water field with artificial turf mat according to the state of the art however shows an increasing ball bounce exceeding the FIH threshold of 40 cm already after about 15 min, see Figure 2A. Moreover, the results show that the ball bounce during the test of 1 hour remains substantially constant, indicating that constant playing and ball characteristics can be guaranteed during a competition of 1 hour. A water field according to the state of the art however (Figure 2A) shows an increasing ball bounce during the test, indicating that the ball and playing characteristics continuously change during a competition.

Figure 3 is a schematic view of the height of the moisture content in time, in which Figure 3A is an illustration of an artificial turf mat according to the state of the art, and in which Figure 3B is an illustration of an artificial turf mat according to the invention. The results show that the moisture content (expressed in % of the initial moisture content, Y-axis) in an artificial turf mat according to the present invention remain relatively constant over the period of 1 hour (expressed in minutes, X-axis). More specifically, during the period, the moisture content does at no time decrease under 90% of the initial content. A water field according to the state of the art however (Figure 3A) shows a continuously decreasing moisture content during the test, and the moisture content finally decreases to almost 60% of the initial moisture content. Experience data show that with a water field with artificial turf mat according to the invention, a water saving of at least 50% to 70% can be realized compared to an artificial turf mat according to the state of the art.

Claims

An artificial turf mat comprising : (i) a backing provided with a plurality of artificial turf fibres, and (ii) a water-retaining base layer provided between said artificial turf fibres, characterised in that said water-retaining base layer is comprised of multifilament fibres.

The artificial turf mat of claim 1, in which said water-retaining base layer is provided with a specific surface weight of 50 gsm to 500 gsm, as determined according to ISO 8543.

The artificial turf mat of claim 2, in which said multifilament fibres are provided with a weight of 1 to 100 dtex per filament.

The artificial turf mat of claim 2 or 3, in which said multifilament fibres are provided with a density of 2,500,000 to 20,000,000 multifilament fibres per square meter.

The artificial turf mat of any one of the claims 2 to 4, in which said multifilament fibres are connected to said backing.

The artificial turf mat of at least any one of the claims 2 to 5, in which said multifilament fibres are provided with a trilobal cross-section.

The artificial turf mat of at least any one of the claims 2 to 6, in which said multifilament fibres are twined.

The artificial turf mat of any one of the claims 1 to 7, in which said artificial turf fibres and/or said water-retaining base layer are made of polyamide.

The artificial turf mat of any one of the claims 1 to 8, in which said artificial turf fibres are comprised of monofilament fibres.

10. The artificial turf mat of any one of the claims 1 to 9, in which said backing is comprised of a ground cloth and a latex coating.

11. The artificial turf mat of any one of the claims 1 to 10, in which said backing is permeable.

12. The artificial turf mat of any one of the claims 1 to 11, in which said artificial turf mat is free of granular filling material .

13. A method for producing an artificial turf mat, comprising the steps:

- providing a water-retaining base layer at said first aide of said ground cloth, in which said water-retaining base layer is comprised of multifilament fibres; and

- coating a second side of said ground cloth, opposite to said first side. 14. The method of claim 13, in which said water-retaining base layer is provided with a specific surface weight of 50 gsm to 500 gsm, as determined according to ISO 8543.

15. A use of an artificial turf mat of any one of the claims 1 to 12, in which water is applied to said artificial turf mat.