TECHNICAL FIELD

The present invention relates to artificial turf mat for sports purposes, such as football and hockey. In particular, the invention relates to biodegradable infill material for artificial turf mat.

BACKGROUND

Increasing demand for high quality playing surfaces and intense competition for field accessibility has given rise to a new generation of turf systems that replicate the look and feel of lush natural grass.

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.

The infill materials of such artificial turfs are of high importance. For example, US10059836B1 provides an eco-friendly infill material. However, such an infill material is not biodegradable. For example, the infill material may move (e.g. during sport activities) to a neighboring field (e.g. agricultural field), and contaminate said field. Making a biodegradable infill material for artificial turf while still keeping the same quality of such turf is challenging.

The present invention aims to resolve at least some of the problems mentioned above.

SUMMARY OF THE INVENTION

In a first aspect, the present invention relates to a biodegradable infill material for artificial turf mat for sports purposes such as football and hockey, according to claim 1. Preferred embodiments of the biodegradable infill material are provided in claims 2 to 9.

The biodegradable infill material comprises polybutylene adipate terephthalate (PBAT). It is an advantage of embodiments of the present invention that the infill material is biodegradable. It is an advantage of embodiments of the present invention that the biodegradable material degrades in soil, preferably within sixty days. It is an advantage of embodiments of the present invention that the biodegradable material meets the Echa standard of biodegradability. It is an advantage of embodiments of the present invention that all particles comprising the biodegradable infill material are biodegradable.

The infill material has a predetermined material density. The infill material is foamed to obtain a foaming material. It is an advantage of embodiments of the present invention that the bulk density is reduced. It is an advantage of embodiments of the present invention that the surface area is increased.

Particles of the infill material are adapted to have a spherical shape, a cylindrical shape, a trilobal shape, or a star shape, triangular shape, or any other suitable shape. It is an advantage of embodiments of the present invention that a low bulk density is obtained due to said shape.

The infill material may further comprise a natural filling material. It is an advantage of embodiments of the present invention that the natural filling material increases the surface area of the infill material, and reduces the polymer content. It is an advantage of embodiments of the present invention that an increased degradation rate is achieved.

It is an advantage of embodiments of the present invention that the biodegradable infill material is free of heavy metals and thus safe and healthy to play on e.g. contact with the human body. It is an advantage of embodiments of the present invention that contamination is prevented, in case some of the infill material moves during sport activities to a neighboring field e.g. agricultural field, and therefore cleaning costs of said field are reduced. It is an advantage of embodiments of the present invention that the infill is eco-friendly.

In a second aspect, the present invention relates to an artificial turf mat, according to claim 10.

The artificial turf mat comprises a mat base, a plurality of artificial turf fibers, and a biodegradable infill material according to the first aspect of the present invention. The plurality of artificial fibers is implanted in the base. The biodegradable infill material is homogeneously spread on the base. The infill material may encompass the fibers on the mat base. The biodegradable infill may be fixed on the mat base by adhesive means, or other suitable fixing means. A first bottom layer of infill may be fixed, while a second top layer may be free to move. The fibers may be mono- or multifilament fibers.

It is an advantage of embodiments of the present invention that the artificial turf mats comprising the biodegradable infill materials are safe and healthy to walk on, and are suitable for sport games.

In a third aspect, the present invention relates to a method for producing a biodegradable infill material, according to claim 11. Preferred embodiments of the method are provided in claim 12 to 14.

The method comprises the steps of providing polybutylene adipate terephthalate (PBAT). The method further comprises extruding said PBAT at temperatures between 150°C and 200°C. The method further comprises the step of foaming the PBAT using reactive foaming agents or by injecting inert gasses such as N2 or Co2 gasses to obtain a foaming material. The method further comprises shaping the foaming material. It is an advantage of embodiments of the present invention that a low bulk density is obtained.

The method may further comprise providing a natural filling material. The method may further comprise the step of homogeneously mixing the natural filling material and the foaming material, such that a biodegradable infill material according to the first aspect of the present invention is obtained.

It is an advantage of embodiments of the present invention that a biodegradable infill material with low bulk density is obtained.

In a fourth aspect, the present invention relates to a method for producing an artificial turf mat.

The method comprises the steps of providing a mat base, and providing a plurality of artificial turf fibers. The method further comprises implanting the fibers in the base. The method further comprises providing a biodegradable infill material according to the first aspect of the present invention. The method further comprises placing the biodegradable infill material on the base, so as to obtain an artificial turf mat comprising a biodegradable infill material, according to the second aspect of the present invention. The method may further comprise the step of fixing at least some of the biodegradable infill material on the artificial turf mat.

In a fifth aspect, the present invention relates to use according to claim 15 of a biodegradable infill material according to the first aspect of the present invention, and/or use of an artificial turf mat, according to the second aspect of the present invention, and/or use of a method for producing an artificial turf mat according to the third aspect of the present invention, for sport activities for sport activities.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a biodegradable infill material for artificial turf mat, suitable for sports purposes such as football and hockey.

Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, term definitions are included to better appreciate the teaching of the present invention.

As used herein, the following terms have the following meanings:

"A", "an", and "the" as used herein refers to both singular and plural referents unless the context clearly dictates otherwise. By way of example, "a contaminant" refers to one or more than one contaminant.

"Comprise," "comprising," and "comprises" and "comprised of" as used herein are synonymous with "include", "including", "includes" or "contain", "containing", "contains" and are inclusive or open-ended terms that specifies the presence of what follows e.g. component and do not exclude or preclude the presence of additional, non-recited components, features, element, members, steps, known in the art or disclosed therein.

The recitation of numerical ranges by endpoints includes all numbers and fractions subsumed within that range, as well as the recited endpoints. In a first aspect, the present invention relates to a biodegradable infill material for artificial turf mat for sports purposes such as football and hockey.

In a preferred embodiment, the biodegradable infill material comprises polybutylene adipate terephthalate (PBAT). The polymer of the infill material is a biodegradable and compostable biopolymer. The infill material has a predetermined material density. The infill material is foamed to obtain a foaming material such that the material density is reduced from 1.26 to 1.00 g/cm ³ , preferably reduced to lower than 0.95 g/cm ³ . The polymer of the foaming material is also biodegradable. The infill material is adapted to degrade in soil, preferably within sixty days.

In a preferred embodiment, the infill material meets the Echa standard of biodegradability. For example, said infill material is biodegradable.

In a preferred embodiment, the foaming material is foamed by reactive foaming agents. This may be for example achieved using a combination of an organic citric acid and calcium carbonate (CaCo3), or by injecting inert gasses such as N2 or Co2 gasses. Foaming increases the surface area, and reduces the bulk density.

In a preferred embodiment, said foaming agents are preferably between 1% and 3% of the infill material.

In a preferred embodiment, said infill material may further comprise Polyhydroxyalkanoates (PHA). Preferably, said PHA is Poly(3-hydroxybutyrate-co-3- hydroxyvalerate) PHBV. For example, the PHA is added to the PBAT.

In a preferred embodiment, said infill material may comprise between 50% and 100% PBAT, and between 0% and 50% PHBV. Preferably, between 60% and 95% PBAT, and between 5% and 40% PHBV. More preferably, between 70% and 93% PBAT, and between 7% and 30% PHBV. Even more preferably, between 80% and

91% PBAT, and between 9% and 20% PHBV. Most preferably, around 90% PBAT and around 10% PHBV. For example, the two are mixed together with these proportions. The inventors noticed that the infill material becomes stiffer for higher PHBV ratio, however were still able to obtain an infill material with ratio of PBAT: PHBV of 50:50. The inventors also noticed that adding PHBV allows the bulk density of the infill material to be lowered, since it has a better and more stable foaming. For example, adding PHBV allows the infill material to foam in a better and more stable way.

In a preferred embodiment, the percentage of PBAT: PHBV: foaming agent is between 50-99:0-50: 1-3, preferably 60-95: 10-40: 1-3, more preferably between 89:9:2

In a preferred embodiment, particles of the infill material are adapted in shape and size to obtain a low bulk density. For example, said particles may have a spherical shape, a cylindrical shape, an elliptical shape, a trilobal shape, a star shape, triangular shape, round shape, stick-like shape, or any other shape that allows a low bulk density.

In a preferred embodiment, the biodegradable infill material may further comprise a natural filling material. For example, organic filling material. The natural filling material may comprise vermiculite, wood fibers, grass fibers, leaf fibers, coconut powder, clay, talcum, silica's, or diatomaceous earth, or a combination thereof. The natural filling material increases the surface area of the infill material, and therefore decreases the polymer content. This is advantageous in increasing the degradation rate. The biodegradable material may comprise bio-based or biodegradable or compostable polymers or additives, such as starch, polylactic acid, Polyvinylalcohol, or cellulose.

In a preferred embodiment, particles of the natural filling material and particles of the foaming material are adapted such that the bulk density is reduced. For example, said particles are adapted in shape and size such that the bulk density is reduced. For example, by increasing the air-filled spaces between the particles. Since the bulk density is reduced, the time needed for degradation of the biodegradable infill material is reduced.

In a preferred embodiment, the bulk density of the biodegradable infill material may be between 0.2 and 0.6 g/cm ³ , preferably between 0.3 and 0.5 g/cm ³ . More preferably, between 0.39 and 0.42 g/cm ³ . The inventors have noticed that said bulk density depends on the process. For example, the bulk density may be reduced when a different process is chosen, for example when underwater granulation is used.

In a preferred embodiment, particles of the foaming material may for example be spherical having a particle diameter between 1 and 5 mm. The particle diameter for both types of materials is for example adapted so as to obtain a low bulk density. In a preferred embodiment, the natural filling material and the foaming material, and any other materials comprised in the biodegradable infill material, are homogeneously mixed e.g. particles in the natural filling material and particles in the foaming material are homogeneously distributed, e.g. equally distributed, e.g. partially or completely randomly distributed.

In a preferred embodiment, the biodegradable infill material is free of heavy metals and thus safe and healthy to play on e.g. contact with the human body. The biodegradable infill material also prevents contamination, in case some of the infill material moves during sport activities to a neighboring field e.g. agricultural field. Therefore, such a biodegradable infill material is eco-friendly.

In a preferred embodiment, the infill material is adapted to provide similar strength and elasticity properties, similar damping properties, similar abrasion properties, as well as similar water retaining properties, to fields with natural grass.

In a preferred embodiment, the biodegradable infill material may sit on a layer comprising sand. Particles in the sand may not mix with the biodegradable infill material. The sand may have a granulometry set between 0.1 and 2.0 mm, preferably between 0.315 and 1.0 mm. The sand particles are preferably round.

In a second aspect, the present invention relates to an artificial turf mat for sports purposes such as football and hockey, using a biodegradable infill material, according to the first aspect of the present invention.

In a preferred embodiment, the artificial turf mat may be used for sporting, recreational, or ornamental purposes. For example, the mat according to the invention may be used as surface on which sporting activities can be played such as football, rain soccer, tennis, hockey, American football, golf, athletics, rugby, baseball and other sports that are played on such mats in general.

In a preferred embodiment, the artificial turf mat comprises a mat base, a plurality of artificial turf fibers, and a biodegradable infill material according to the first aspect of the present invention. The mat base may for example be a carpet or a mat, or any other base adapted to receive the plurality of artificial turf fibers, e.g. by sewing them to the carpet, or e.g. fixing them through holes or recesses or other means adapted to receive and fix said fibers on the carpet, or e.g. sticking or gluing them or e.g. implanting them in another suitable mechanism. The mat is further adapted to receive the biodegradable infill material. The mat is further adapted for humans to walk thereon. For example, the mat is safe and healthy to walk on e.g. to play on.

In a preferred embodiment, the mat base may have one side to receive the fibers, and another side that touches the ground. For example, the side that touches the ground has friction with the ground e.g. by making it of a suitable material, so as to fix the mat base in place e.g. to reduce the movement of the base.

In a preferred embodiment, the plurality of fibers is fixed on the mat base, such that for example each fiber has a part in the mat or below the mat, so as to fix the fiber in place. For example, a sufficiently big part of each fiber is in the mat or below the mat e.g. at least 10% or e.g. at least 20%, so as to fix the fibers in place.

In a preferred embodiment, the fibers are spread on the mat homogeneously e.g. spaced similarly from one another.

In a preferred embodiment, the fibers are tufted or woven such that the fibers protrude from one side of the mat. Most preferably, the fibers are tufted. For example, the fibers protrude through the infill material. The fibers maybe from a synthetic material. Said fibers may not be blown away by the wind.

In a preferred embodiment, the biodegradable infill material is homogeneously spread on the base. The biodegradable infill material encompasses the fibers e.g. surround the fibers from most directions e.g. from all directions, such e.g. that the base is completely covered by the biodegradable infill material. The infill may at least partially be fixed, e.g. at least a first layer e.g. a first bottom layer on the base, e.g. to prevent the base from being exposed after a long use when the infill is spread or moved around by the feet of e.g. football players. There is preferably no contact between e.g. the feet of the players and the base. The biodegradable infill material may be fixed, at least a first layer, e.g. a first bottom layer by e.g. adhesive means e.g. gluing said infill. A second top layer may be free to move e.g. may not be fixed. In a preferred embodiment, the fibers may be mono- or multifilament fibers.

In a third aspect, the present invention relates to a method for producing a biodegradable infill material. In a preferred embodiment, the method is for producing a biodegradable infill material, wherein the biodegradable infill material is according to embodiments of the first aspect of the present invention.

In a preferred embodiment, the method comprises the step of providing polybutylene adipate terephthalate PBAT.

In a preferred embodiment, the method may further comprise the step of providing Polyhydroxyalkanoates (PHA). Preferably, providing Poly(3-hydroxybutyrate-co-3- hydroxyvalerate) PHBV.

In a preferred embodiment, the method may further comprise the step of providing the infill material having between 50% and 100% PBAT, and between 0% and 50% PHBV. Preferably, between 60% and 95% PBAT, and between 5% and 40% PHBV. More preferably, between 70% and 93% PBAT, and between 7% and 30% PHBV. Even more preferably, between 80% and 91% PBAT, and between 9% and 20% PHBV. Most preferably, around 90% PBAT and around 10% PHBV.

In a preferred embodiment, the method further comprises the step of extruding said PBAT at temperatures between 150°C and 200°C, preferably between 160°C and 185°C.

In a preferred embodiment, the method further comprises foaming the PBAT using reactive foaming agents, such as a combination of an organic citric acid and calcium carbonate CaCo3, or by injecting inert gasses (e.g. N2 or CO2) to obtain a foaming material. Preferably, said foaming agents are preferably between 1% and 3% of the infill material.

In a preferred embodiment, the method further comprises the step of shaping the foaming material, for example such that particles of the foaming material may have a particle diameter between 1 and 5 mm. During the step of shaping, the shape and the size are adapted so as to obtain a low bulk density.

In a preferred embodiment, the method may further comprise the step of providing a natural filling material. For example, providing vermiculite, wood fibers, grass fibers, coconut powder, clay, talcum, silica's, diatomaceous earth, starch, cellulose, polyvinylalcohol, or polylactic acid or a combination thereof. In a preferred embodiment, the method may further comprise the step of homogeneously mixing the foaming material and the natural filling material, such that a biodegradable infill material according to the first aspect of the present invention is obtained.

In a preferred embodiment, the method may further comprise shaping the natural filling material. During said step of shaping, the shape and size are adapted so as to obtain a low bulk density.

In a preferred embodiment, the method may further comprise softening the biodegradable infill material.

In a fourth aspect, the present invention relates to a method for producing an artificial turf mat.

In a preferred embodiment, the method comprises the steps of providing a mat base, and providing a plurality of artificial turf fibers, according to the second aspect of the present invention. In a preferred embodiment, the method further comprises implanting the fibers in the base.

In a preferred embodiment, the method further comprises providing a biodegradable infill material according to the first aspect of the present invention.

In a preferred embodiment, the method further comprises placing the biodegradable infill material on the base, so as to obtain an artificial turf mat comprising a biodegradable infill material, according to the second aspect of the present invention. Implanting and placing may be done manually or by machines. The method preferably comprises placing and spreading the biodegradable infill material homogeneously on the base.

In a preferred embodiment, the method may further comprise the step of fixing at least some of the biodegradable infill material on the artificial turf mat. The step may comprise fixing at least a first layer of biodegradable infill material e.g. a basic layer, e.g. to cover e.g. permanently the base of the artificial turf mat.

In a preferred embodiment, the method may further comprise the step of providing a layer comprising sand sitting below the biodegradable infill material. In a fifth aspect, the present invention relates to use of a biodegradable infill material according to the first aspect of the present invention, and/or use of an artificial turf mat, according to the second aspect of the present invention, and/or use of a method for producing an artificial turf mat according to the third aspect of the present invention, for sport activities.

The preceding description gives details of certain embodiments of the present invention. It will, however, be clear that no matter how detailed the above turns out to be in text, the invention may be applied in many ways. It should be noted that the use of certain terminology when describing certain characteristics or aspects of the invention should not be interpreted as implying that the terminology herein is defined again to be restricted to specific characteristics or aspects of the invention to which this terminology is coupled.