Infill for artificial turf

Abstract

The present invention relates generally to the field of filler particles for artificial turf. More particularly, the present invention relates to filler particles for artificial turf, the particles comprising a salt-impregnated substrate and free of thermoplastic material, the substrate comprising a cellulosic and / or hemicellulosic material, the particles having a size of about 512 mm. 3 and the particles have a salt content of at least 5% by weight, the salt being dispersed throughout the particles. The invention also relates to methods of making the infill particles of the invention, and to artificial turf systems comprising these particles.

Description

[Technical field]

[0001] The present invention generally relates to filler particles for artificial turf. More specifically, the present invention relates to filler particles for artificial turf, the particles being made from organic materials. The present invention also relates to a method for producing the filler particles of the present invention, and to an artificial turf system comprising these particles. [Background technology]

[0002] Artificial turf has become an important alternative to natural grass in several types of environments. Football uses artificial turf in most cases, both indoors and outdoors. Although artificial turf systems can vary in their design and manufacture, they generally all share common components. The artificial turf fiber (or turf pile or artificial turf) itself is usually made from polyethylene glycol (PE) with a primary backing material of polypropylene (PP) that provides the structure and spacing into which the artificial turf fibers are woven. A secondary backing of polyurethane (PU) can be applied and cured to bond the pile to the backing. Such a backing forms a "turf carpet".

[0003] There are several different types of artificial turf systems, including hybrid, first generation (1G), second generation (2G), and third generation (3G) turf systems. Hybrid turf or reinforced natural turf is turf created by combining natural grass with synthetic reinforcing fibers. First generation artificial turf systems contain short artificial turf fibers. First generation artificial turf systems have been largely supplanted by second and third generation artificial turf systems. Second generation artificial turf systems have longer fibers (e.g., 13-24 mm height) and sand infill.

[0004] Third generation systems typically contain even longer fibres (e.g. 30-60mm in height) and two types of infill, namely "stabilising infill" (typically sand) and "performance infill". Typically the stabilising infill is placed as an underlayer between the artificial turf fibres and the performance infill is placed on top of the stabilising infill as an overlayer between the artificial turf fibres. The stabilising infill functions to keep the artificial turf fibres vertical during use and the performance infill functions to mimic the feel of a natural grass floor, for example by providing precise levels of impact resistance, rolling resistance and rebound. Currently the performance infill used in most artificial turf systems is styrene-butadiene rubber (SBR) (also known as crumb rubber), which is derived from used automobile tyres. If required, shock pads can be provided under the turf carpet to provide further support.

[0005] In a typical artificial grass pitch measuring 106 x 71 metres with SBR as the performance infill, 49% of the total weight is made up of stabilised infill (sand) and 44% of the total weight is made up of the performance infill (SBR). The remainder is the plastic-based grass itself, i.e. the grass carpet and the artificial grass fibres.

[0006] The environmental impact of artificial turf systems is therefore often dominated by the infill material. The performance infill market is dominated by SBR, with approximately 83% of installations incorporating this material. Sand is also a large component of 3G turf systems as a stabilised infill, but requires significantly less energy and processing for recycling compared to SBR. It is estimated that 10% of infill leaks out of artificial turf systems each year, i.e. is dispersed into the wider environment.

[0007] Since SBR is resistant to biodegradation and is ecotoxic, leakage of SBR granules has been shown to cause significant environmental problems. Therefore, there is a need to provide a filler that is biodegradable after leakage from artificial turf, is not ecotoxic, and has a lower environmental impact.

[0008] Cork granules are one of the few known natural infill alternatives. However, they are not ideal for all applications as they are expensive and tend to degrade over time on artificial turf at a faster rate than rubber, meaning the infill needs to be replenished more regularly over the life of the artificial turf. Summary of the Invention

[0009] The present invention provides an infill for artificial turf that meets the above-mentioned needs. The infill of the present invention is demonstrated to have achieved FIFA Quality PRO and FIFA Quality certification (by meeting the performance requirements outlined in EN15330-1:2013) based on tests conducted in the accredited FIFA Laboratory-Sports Research Institute (see Example 3).

[0010] In particular, the present invention relates to infill particles for artificial turf, having a salt content of at least 5% by weight, preferably at least 10% by weight, and having a surface area of ​​about 512 mm 3 and the filler particles are made of wood.

[0011] The inventors have surprisingly found that wood has technical properties comparable to those of SBR granules. The filler particles of the invention therefore constitute a product capable of performing the functions of SBR without the attendant environmental damage caused by leakage of the filler.

[0012] The particles are impregnated with a high content of salt. The level of salt in the filler particles of the present invention contributes to the particles behaving stably and not degrading too quickly (resistant to decomposition and disintegration). Without wishing to be bound by theory, this efficacy is brought about by the salt's ability to repel microorganisms and fungi, thereby giving the filler particles resistance to biodegradation, and the salt also contributes to the particles' resistance to UV radiation. The salt also makes the particles denser, which gives them better properties as a filler (e.g. for sports pitches) than wood that is not impregnated with a high concentration of salt. Even in high concentrations, the salt is not harmful to the environment and is not toxic to humans or other animals that may come into contact with the filler, nor is it harmful to the wider environment.

[0013] The infill has been demonstrated to be stable on artificial turf for at least 5 years and is predicted to be stable for 10 years. The lifespan of artificial turf (i.e., turf carpet containing artificial turf fibers) is approximately 10 years, thus reducing the need to replace or replenish the infill of the present invention over the lifespan of the artificial turf, unlike cork and other known organic infills.

[0014] Throughout this specification, where the terms "comprising", "comprise", and "comprises" are used, the terms "consisting of", "consist", and "consists" are also intended as alternatives.

[0015] "Infill" means any solid particle suitable for use on an artificial turf. Particles suitable for use on an artificial turf may be particles that mimic the properties of natural grass or a natural turf floor as part of a turf system. The properties mimicked may be ball rebound, ball roll, shock absorption, vertical deformation, foot roll resistance, and / or water permeability.

[0016] Thus, in some embodiments, the infill of the present invention is an infill for artificial turf (e.g., artificial football turf). In a preferred embodiment, the infill of the present invention is for (or suitable for, or suitable for use on) an artificial turf (e.g., artificial football turf) having artificial turf fibers (preferably monofilament fibers, fibrillated fibers, monofilament fibers with stems, or a combination thereof) having a height of about 25 to 70 mm (preferably a height of about 30 to 50 mm, more preferably a height of about 40 mm). More preferably, the infill of the present invention is for (or suitable for, or suitable for use on) an artificial turf (or artificial football turf) having artificial turf fibers that are monofilament turf fibers and have a height of about 40 mm. In a preferred embodiment, the infill of the present invention is for (or suitable for, or suitable for use on) a third generation (3G) artificial turf. In other words, in a preferred embodiment, the infill of the present invention is a third generation (3G) artificial turf infill.

[0017] In a preferred embodiment, the infill of the present invention is a performance infill, preferably a performance infill for (or suitable for or suitable for use on) artificial turf, more preferably a performance infill for (or suitable for or suitable for use on) third generation artificial turf.

[0018] The filler particles (or fillers) of the present invention may be referred to simply as "particles." [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a graph showing the particle size of the filler particles. [Diagram 2] Figure 2A shows a new, unused filler particle, Figure 2B shows the same type of particle after the filler particle was subjected to 20,200 cycles of simulated wear, and Figure 2C shows a particle of the same composition after the filler particle was subjected to 40,200 cycles of simulated wear. [Diagram 3]FIG. 3 shows the results of Example 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The filler particles of the present invention include a substrate (also called a base material) impregnated with salt. In the present invention, the substrate is preferably wood. However, more broadly, it is also contemplated herein that the substrate comprises (or is formed from, or consists of, or consists essentially of) other cellulosic and / or hemicellulosic materials. Thus, when wood is discussed herein, it should be understood that other cellulosic and / or hemicellulosic materials (including lignocellulosic materials) are contemplated. Examples of such other non-wood substrates include nut shells, olive stones, cork, coconut, walnut shells, and / or corn cobs.

[0021] The present invention therefore also relates to infill particles for artificial turf, the particles having a salt content of at least 5% by weight, preferably at least 10% by weight, and having a surface area of ​​about 512 mm 3 and the filler particles are made of cellulosic and / or hemicellulosic materials.

[0022] The wood of the filler particles may be whole wood or raw wood. Preferably, the wood is not reconstituted or processed wood. For example, preferably, the wood is not formed from compressed or blended sawdust.

[0023] Preferably, the filler particles do not contain non-biodegradable materials.

[0024] Preferably, the filler particles (or substrate) do not contain thermoplastic materials. Composite filler particles in the art may contain thermoplastic materials, the purpose of which is to bond the substituents of the particles together. However, thermoplastic materials are disadvantageous for use in filler particles, as they are potentially damaging to the environment (thermoplastic materials used in filler particles may be synthetic and non-biodegradable). In contrast, the method of making filler particles of the present invention allows salt treatment without the need to break down the natural structure of cellulosic or hemicellulosic materials and then recombine the fibers. This means that there is no need to use thermoplastic materials, which is beneficial.

[0025] Most preferably, the substrate of the filler particles consists (or consists essentially) of wood (or cellulose and / or hemicellulose) material.

[0026] The filler particles of the present invention may be genetically engineered, raw material, or man-made, preferably raw material.

[0027] The salt is an inorganic salt, typically comprising, consisting of, or essentially consisting of a chloride salt. In a preferred embodiment, the salt is sodium chloride, magnesium chloride, calcium chloride, potassium chloride, sodium sulfate, magnesium sulfate, calcium sulfate, potassium sulfate, or a mixture thereof. In a more preferred embodiment, the salt is sodium chloride, magnesium chloride, calcium chloride, potassium chloride, or a mixture thereof. In a more preferred embodiment, the salt is composed of or essentially composed of sodium chloride, i.e., the inorganic salt component is at least 95% NaCl, preferably at least 98% NaCl.

[0028] In some embodiments, the salt content (or salt concentration) of the filler particles is at least (or at most) about 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50% by weight. Preferably, the salt content (or salt concentration) of the filler particles is at least about 7%, at least about 10%, at least about 15%, at least about 20%, at least about 30%, or at least about 40% by weight. Preferably, the salt content of the filler particles is about 10-55% by weight, such as 10-40%, 20-50%, or 30-50% by weight, and in some preferred embodiments about 20-35% by weight. For the avoidance of doubt, the term "% by weight" refers to the % (percentage) of the total weight of the filler particles including the salt as a constituent. Instead of the term "% by weight", the terms "% weight", "% by mass" or "% mass" can equally be used.

[0029] The weight % of salt is calculated based on dry particles, e.g. particles that have been under dry ambient conditions for at least one week. Dry ambient conditions may be those found in a building at normal room temperature (e.g. 20 degrees Celsius) and normal humidity conditions, e.g. 30-50% humidity (e.g. 40% humidity).

[0030] In some embodiments, the salt content (or salt concentration) of the filler particles is at least (or at most) about 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49 or 50% by volume. Preferably, the salt content (or salt concentration) of the filler particles is at least about 5% by volume, or at least about 10% by volume. Preferably, the salt content is about 5-15% by volume. For the avoidance of doubt, the term "% by volume" refers to the % of the total volume of the filler particles that includes the salt as a component. Instead of the term "% by volume", the term "% volume" may be used.

[0031] The volume percent of salt is calculated based on dry particles, eg, particles that have been under dry ambient conditions for at least one week.

[0032] The size of the filler particles can be conveniently defined by the volume of the particle, which may be up to about 512, 500, 400, 343, 300, 216, 200, 175, 125, 120, 115, 110, 105, 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, or 10 mm. 3 The volume of the filler particles may be at least about 0.001, 0.008, 0.01, 0.1, 1, 2, 3, 4, or 5 mm 3 Preferably, the volume of the filler particles is about 0.008 mm 3 ~Approx. 64mm 3 , or about 0.008 mm 3 ~approx. 125mm 3 More preferably, the volume of the filler particles is about 0.1 mm 3 ~approx. 125mm 3 Most preferably, the volume of the filler particles is about 0.5 mm 3 ~Approx. 64mm 3 , for example, about 1 mm 3~ approx. 10 or 20 mm 3 , especially about 8 mm 3 Volume should be understood as the size of a particle measured or calculated from its dimensions; the volume of a particle is not reduced merely because it may contain pores (i.e., voids). Thus, a preferred particle, each of which is a 2 mm cube, may be 8 mm 3 It has a volume of

[0033] Preferably, the filler particles are about 0.001 mm 3 ~Approx. 512mm 3 , more preferably about 0.008 mm 3 ~approx. 125mm 3 , more preferably about 1 mm 3 ~Approx. 64mm 3 , more preferably about 1 mm 3 ~approx. 27mm 3 It has a volume of

[0034] Most preferably, the filler particles have dimensions of 2×2×2 mm and a diameter of about 8 mm. 3 It is a cube having a volume of 1×1×1 mm. As demonstrated herein, particles having dimensions of 2×2×2 mm are particularly suitable for use as infill for artificial turf. It is demonstrated herein that such particles are resistant to degradation on artificial turf for a long period (at least 5 years, possibly 10 years or more), but advantageously degrade quickly in soil. Such particles are also demonstrated herein to be resistant to freezing down to -18°C. The 2×2×2 mm size itself is also particularly suitable for artificial turf, being particularly complementary to the size and spacing of grass fibers typically found on artificial turf carpets. Particles of 2×2×2 mm size can also be efficiently manufactured. Particles that are 1×1×1 mm cubes are also very preferred and exhibit excellent performance as infill. As rectangular parallelepipeds with the same dimensions, cubes having dimensions of 0.5-4×0.5-4×0.5-4 mm are generally preferred.

[0035] As demonstrated herein, the rounding of the corners of the particles reduces the rolling and slipping of boots on the turf, and therefore salt-treated particles with rounded corners are particularly advantageous as infill for artificial turf.As demonstrated herein, such rounding can be achieved simply by the wear of the particles during use on the artificial turf, and therefore rounding does not need to be performed during the manufacture of the particles, thus reducing production costs.Nevertheless, rounding of the corners of the cube / rectangle can be performed during the manufacture of the particles, if desired, as described elsewhere herein.

[0036] The filler particles can be any shape, preferably any shape suitable for use on artificial turf, more preferably any shape suitable for use on third generation artificial turf. The filler particles can be any polyhedral shape. In a preferred embodiment, the filler particles have the shape (or approximate shape) of a cube, a rectangular prism, a sphere, an ellipsoid, a spheroid, an ovoid, or a pyramid, such as a tetrahedron or a square pyramid. In a preferred embodiment, the filler particles have the shape (or approximate shape) of a rectangular prism or a cube, more preferably a cube. Thus, the particles are preferably (approximately) equal in their three dimensions. Preferably, one dimension does not exceed 1.5 times the length of any other dimension.

[0037] In other embodiments, particles with dimensions such as elongated or flat cuboids, for example 1x2x2mm, may be preferred.Other preferred shapes include 1x1x4mm, 1x1x2mm, 2x4x4mm, and 2x2x4mm.Such particles can make artificial turf less slippery (for example, by providing more rolling resistance) compared to cubic filler particles.

[0038] The shape of the rectangular prism particles is preferably flat rather than elongated, in other words one dimension is smaller than the other two dimensions which are the same or nearly the same (rather than one dimension larger than the other two as in the case of elongated prisms / particles).

[0039] In another preferred embodiment, the particles are spheres or spheroids, with a preferred diameter of 0.5 to 4 mm, preferably 1 to 2 mm.

[0040] Particles are three-dimensional bodies, and for three-dimensional objects, the aspect ratio is understood to be the ratio of the longest dimension to the shortest dimension. Rectangular prisms are contemplated where two dimensions are the same, one longer or shorter than the other two, or where all three dimensions are different. Thus, rectangular prism particles may define an aspect ratio of at least (or at most) 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, or 10:1. Preferably, the aspect ratio is between 1:1 and 10:1, more preferably between 2:1 and 10:1, more preferably between 2:1 and 5:1.

[0041] In some embodiments, the filler particles have width to thickness dimensions in the range of about (0.5 mm to 5 mm) x (0.5 mm to 5 mm), hi some embodiments, the filler particles have cross-sectional and / or length dimensions of about 1 mm to about 5 mm.

[0042] In some embodiments, the filler particles have a length between 1 mm and 5 mm and / or an aspect ratio between 3:1 and 7:1.

[0043] In some preferred embodiments, the filler particles of the present invention have a smooth or polished surface. A "smooth or polished" surface according to the present invention is a surface that has been treated to reduce roughness and / or to soften the sharpness or angle of edges and corners.

[0044] In some embodiments, the vertices (or corners) of the treated filler particle shape are rounded. Filler particles of the present invention with rounded vertices (or corners) can be advantageous because the roundness improves the rolling resistance of the turf in which the filler is distributed. Rolling resistance refers to the ability of the turf to resist the rolling movement of the sole (or foot or boot) when pushing down on the turf. Preferably, the filler particles have a cuboid or rectangular shape with rounded corners.

[0045] In some embodiments, some of the outer pores of the filler particles of the present invention are sealed so as not to provide an open channel from the outside of the particle to the inside of the particle.At least 10%, 20%, 30%, 50% or 70% of the pores that open to the surface of the particle can be preferably sealed.The pores of the filler particles of the present invention can be sealed by grinding the particle.

[0046] The water absorption of the filler particles of the present invention can be reduced compared to raw wood particles of the same size. The water absorption of the filler particles of the present invention can be reduced by having a smooth or polished surface. Alternatively or additionally, the water absorption of the filler particles of the present invention can be reduced by impregnating them with oil or preservatives.

[0047] Nevertheless, it is preferred that the particles are able to absorb some water so that they behave like a sponge and can mimic the conditions of a traditional grass pitch in different weather conditions, i.e. harder in dry weather and softer in rain.

[0048] The filler particles of the present invention may (or may not) be impregnated with an oil or preservative, which acts as a protective coating (e.g., a waterproof coating) for the filler particle and which acts to improve retention of salts within the particle.

[0049] Thus, in a preferred embodiment, the oil is a natural oil (i.e., plant-derived) and the preservative is a natural preservative. In a preferred embodiment, the oil is linseed oil (e.g., cold-pressed linseed oil). Alternative oils include tung oil, olive oil, rapeseed oil or sunflower oil.

[0050] In preferred embodiments, the filler particles do not include a coating. In preferred embodiments, the filler particles do not contain (or are not coated with) glycerol, xylitol or sorbitol, and more preferably do not contain polyols. In some preferred embodiments, the filler particles do not contain potassium acetate, sodium formate, sodium acetate, urea, sodium chloride, and / or calcium chloride.

[0051] However, in some embodiments, in addition to the salt, a glycerol (glycerin) coating may be applied, usually in a separate application step.

[0052] The salt treatment process significantly increases the density / weight of the wood, which provides superior properties compared to unsalted wood, in particular this allows the particles to meet the density requirements set by FIFA for packing. Thus, for example, the density of the dry particles is increased by 20-60%, preferably at least 30%, by the addition of salt. Preferably, the dry particles have a density of 0.3-0.7 g / ml, more preferably 0.4-0.7 g / ml, in some embodiments 0.65-0.70 g / ml.

[0053] In some embodiments, the particles have a moisture content of about 16-20% when packaged for sale or applied to a turf system or placed on a pitch (which can still be considered dry particles). The filler particles of the present invention typically have a density higher than (or about the same as) pure water, so that the filler particles tend to sink when in pure water. It should be understood that although the (dry) particles may initially float due to the buoyancy of the wood, when placed in water (e.g., after 30 minutes), water is taken up and the particles then become denser than water and sink. The salt content makes the wet particles denser than water, despite the fact that wood is naturally buoyant in water.

[0054] Overall, the density of the particles depends on the saturation and salt content, and therefore on the amount of salt added to the substrate particles, as well as the ambient or environmental conditions that affect how much moisture is present (taken up) in the particles. Generally, densities vary from 0.5 g / ml to over 1.0 g / ml (e.g., up to 1.1, 1.2 or 1.4 g / ml).

[0055] The wood of the particles may be, for example, natural or raw wood, as opposed to engineered wood products which may be formed from reconstituted chips or plies, which may have non-wood binders such as resins or adhesives.

[0056] The wood of the particles may be softwood or hardwood, with hardwood being preferred.

[0057] Suitable softwoods include Araucaria, Cedar (Cedrus decastes), Celery Top Pine (Phyllocladus asplenifolia), Cypress (Chamaecyparis obtusifolius, Cypress cypress, Cypress serrata, etc.), Douglas Fir (Picea quinquefolia), European Yew (Taxus baccata), Fir (Abies), Hemlock (Tsuga aralia), Huon Pine, Macquarie Pine (Lagarostrobus franklinii), Kauri (Agathis australis), Queensland Japanese Kauri (Agathis australis), and Japanese Cedar (Prunus persica). These include kauri (Agathis robusta), Japanese torreya (Torreya nucifera), larch (Larix ardisiacus), pine (Pinus ardisiacus), red cedar (such as Juniperus or Red Cedar), coast redwood (Sequoia sempervirens), rimu (Dacridium capresinum), spruce (Pikea ardisiacus), Japanese cedar (Cryptomeria japonica), white cedar (such as Thuja occidentalis or Chamaecyparis obtusifolia), or Nootka cypress (Chamaecyparis albicilla).

[0058] Suitable hardwoods include birch (Betula), alder (Alnus), ash (Fraxinus), aspen (Populus), Australian red cedar (Tuna ciliata), boxelder (Acer negundo), boxwood (Boxwood), Brazilian walnut (Ocotea porosa), Brazilwood (Caesalpinia echinata), Aesculus, Catalpa, Ceylon satinwood (Chloroxylon sweetenia), cherry (Prunus), chestnut (Castanea), coachwood (Ceratopetalum apetalum), corkwood (Laithoneria florida), These include poplar, dogwood (Cornus), ebony (Diospyros), elm (Ulumus), eucalyptus, European crabapple (Malus sylvestris), European pear (Pyrus communis), ironwood, kingwood (Dalbergia cearenus), lacewood, mahogany (Sweetania, Haya, Tuna, Entandrophragma, Chukrasia, Cedrera, Guarea, Carapa, Melia, etc.), maple (Acer), marblewood (Marmaroxylon racemosum), oak (Quercus), walnut (Juglans), or willow (Salix).

[0059] In some preferred embodiments, the softwood is spruce (Pikea), more preferably Sitka spruce (Pikea sithensis).

[0060] In some particularly preferred embodiments, the hardwood is a birch (Betula), such as American birch, preferably gray birch (Betula populifolia), black birch (Betula nigra), paper birch (Betula papyrifera), sweet birch (Betula lenta), Virginia roundleaf birch (Betula uber) or yellow birch (Betula alleghaniensis). In some preferred embodiments, the birch is a European birch, preferably silver birch (Betula pendula) or most preferably downy birch (Betula pubescens).

[0061] Birch is preferred as a substrate for the filler particles of the present invention due to its particularly advantageous properties, as demonstrated in the examples. Birch is also particularly advantageous because it has a uniform structure throughout the body, allowing for the production of uniform particles. This is important because it provides consistency in physical properties between batches of filler particles. This homogeneity is in contrast to more heterogeneous woods, such as southern yellow pine, which is harder and more compact toward the center of the tree but softer and less compact in the outer layers. Thus, woods such as southern yellow pine are not as ideal for making filler particles as other woods, particularly birch, preferably European birch.

[0062] Birch wood, which is used as the preferred substrate for the filler particles of the present invention, also has improved properties in terms of energy return (it provides greater "bounce back") than other woods such as, for example, southern yellow pine.

[0063] Preferably, the plurality of filler particles of the present invention are homogenous in size, e.g., at least 70, 80 or 90% of the particles have a volume that is within 20%, preferably within 10%, e.g., 5% (plus or minus) of the average volume.

[0064] The filler particles of the present invention are resistant to biodegradation on artificial turf. Biodegradation is the decomposition of organic matter by microorganisms such as bacteria and fungi. In fact, almost all biological compounds and materials undergo a biodegradation process. However, the importance lies in the speed of such processes, such as days, weeks, years or centuries. Since organic matter is particularly susceptible to biodegradation, the level of resistance of the organic filler to biodegradation is important in determining the lifespan of the organic filler.

[0065] The filler particles of the present invention are demonstrated herein to be stable on artificial turf for at least 5 years, and are expected to last for at least 10 years (in contrast, when the filler particles are placed in soil, they are completely biodegraded within 3 months).This is particularly beneficial, as it means that the filler of the present invention is commercially useful as a filler for artificial turf.

[0066] The particles are preferably stable, eg, capable of retaining their functional properties and structure when placed on an artificial turf for at least five years.

[0067] For an artificial turf system to function during cold weather, it is important that the infill (including performance infill) does not freeze, otherwise the surface will not mimic the conditions of a normal grass floor. Frozen infill does not have the same advantageous properties as non-frozen infill. It is therefore desirable for any infill particles to be resistant to freezing to low temperatures.

[0068] The filler particles of the present invention are freeze-resistant. Without wishing to be bound by theory, this may be due to the high salt content (or salt concentration) of the filler particles, and may also be due to the wood of the filler particles. The filler particles of the present invention are freeze-resistant, i.e., do not freeze down to -10, -15, or -18°C.

[0069] In certain events taking place on artificial turf, pyrotechnics and / or fireworks may be used (e.g., during breaks in play at sporting events). For this to be feasible, it is important that the artificial turf is fire resistant. As the infill makes up a large part of the artificial turf, it is important that the infill is fire resistant in these circumstances.

[0070] Thus, in embodiments, the filler particles of the present invention are fire resistant or non-combustible. In embodiments, the filler particles of the present invention are substantially fire resistant or completely fire resistant. In embodiments, the filler particles of the present invention are more fire resistant than the corresponding non-salted or unmodified versions of the particles.

[0071] The filler particles of the present invention are preferably less susceptible to degradation by UV radiation than untreated wood of the same size.

[0072] The filler particles used in accordance with the present invention may comprise filler particles of two or more shapes, in a preferred embodiment, the two or more shapes are selected from the group consisting of cubes, rectangular prisms, spheres, ellipsoids, spheroids, ovoids and pyramids.

[0073] The filler particles used according to the present invention may include two or more sizes of filler particles. In some embodiments, the plurality of filler particles of the present invention may include a first type of filler particles and a second type of filler particles, and the first type of filler particles has a volume at least two or three times the size of the second type of filler particles. For example, cubes of two different sizes can be used together, such as a 1mm x 1mm x 1mm cube and a 2mm x 2mm x 2mm cube.

[0074] The particles of the present invention may be used with a second particle made from a different substrate. In a preferred embodiment, the second particle is sand, e.g., silica sand.

[0075] The artificial turf system of the present invention can include a lower layer of particles and an upper layer of particles, the upper layer including the particles of the present invention, and the lower layer including a second particle type suitable for use as an artificial turf infill. In a preferred embodiment, the second particle type is sand. In a preferred embodiment, the sand is silica sand. In such a configuration, the infill particles of the present invention can be referred to as a performance infill, and the second particle type (e.g., sand) is a stabilizing infill.

[0076] In some embodiments, the filler particles have a packing factor of about 1.5, 2, 2.5 or 3, preferably about 2. Packing factor is a measure of the total volume of a packed group of particles divided by the total volume of all individual particles. Thus, the added volume in a collection of particles (compared to the total volume of all individual particles) is the empty space between the packed particles.

[0077] The filling factor therefore reflects the volume of air present between the particles. The air between the particles contributes to the softness and technical properties of the infill (and of the turf surface when the infill is applied to it). It may therefore be advantageous to have a filling factor of more than 1. In particular, the infill particles of the invention may have a filling factor of 1 to 3, 1.5 to 2.5 or about 2.

[0078] The present invention also provides a method for producing the filler particles of the present invention, the method comprising the steps of: 3 The method includes immersing particles having a volume of up to 1000 μm in a salt solution and, optionally, drying the immersed particles.

[0079] In the present invention, wood is generally a preferred example of a cellulose and / or hemicellulose particle. The present invention therefore also relates to a method for producing the filler particles of the present invention, which comprises producing filler particles made of cellulosic and / or hemicellulose materials and having a size of about 512 mm. 3 In one embodiment, the method comprises immersing particles having a volume of up to 100 μm in a salt solution and, optionally, drying the immersed particles.

[0080] In embodiments, the wood particles are up to about 512, 500, 400, 343, 300, 216, 200, 175, 125, 120, 115, 110, 105, 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15 or 10 mm 3 The volume of the wood particles is at least about 0.001, 0.008, 0.01, 0.1, 1, 2, 3, 4 or 5 mm 3 Preferably, the volume of the wood particles is about 0.008 mm 3 ~Approx. 64mm 3 , or about 0.008 mm 3 ~approx. 125mm 3 More preferably, the volume of the wood particles is about 0.1 mm 3 ~approx. 125mm 3Most preferably, the volume of the wood particles is about 0.5 mm 3 ~Approx. 64mm 3 , for example, about 1 mm 3 ~ approx. 10 or 20 mm 3 , especially about 8 mm 3 Volume should be understood as the size of a particle measured or calculated from its dimensions; the volume of a particle is not reduced merely because it may contain pores (i.e., voids). Thus, a preferred particle, each of which is a 2 mm cube, may be 8 mm 3 Preferably, the wood particles have a volume of about 0.001 mm 3 ~Approx. 512mm 3 , more preferably about 0.008 mm 3 ~approx. 125mm 3 , more preferably about 1 mm 3 ~Approx. 64mm 3 , more preferably about 1 mm 3 ~approx. 27mm 3 It has a volume of

[0081] The preferred characteristics of the particles defined above apply mutatis mutandis to this method.

[0082] In some embodiments, the wood particles have corners and edges, and the corners and edges are rounded.

[0083] The soaking step is sufficient to provide the particles with a salt content as described herein, i.e., at least 5% by weight, preferably at least 10% by weight salt. The soaking step may be sufficient to cause the salt to penetrate throughout the particles.

[0084] The particles are immersed in salt water, where the water preferably has a salt concentration of at least about 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350 or 360 g / L (i.e. grams per liter). Preferably, the salt solution is a saturated salt solution, the exact concentration at which saturation is reached depending on the temperature of the water. Preferably, the salt concentration is between 300 and 400 g / L, more preferably between 320 and 380 g / L, for example about 360 g / L.

[0085] Prior to and / or during immersion the salt solution (brine) is preferably heated, for example to at least 50° C., at least 70 or 75° C., or to about boiling point. A preferred temperature is 70-80° C., for example about 75° C. Conveniently the water can be heated prior to the addition of the salt and then the particles can be added to the brine / salt solution.

[0086] The rate of uptake of a liquid (e.g., water or salt water) by a wood sample can increase with a decrease in liquid viscosity and with an increase in the surface area and permeability of the wood. The viscosity of the liquid (e.g., salt water) can be decreased and the surface area (e.g., due to cellulose and hemicellulose expansion) and permeability (e.g., due to pore expansion) of the wood can be increased by increasing the temperature of the liquid and the wood, respectively. Thus, by salting wood particles in salt water at elevated temperatures, the rate of salt uptake by the particles is significantly increased compared to the same procedure at ambient temperature (i.e., the salt uptake step can be as fast as, e.g., 15 minutes when performed at elevated temperatures, as opposed to days or weeks when performed at ambient temperatures). Immersion in a heated salt solution is usually, but not always, preferred.

[0087] In the immersion method of the present invention, the liquid not only passes through the wood fibers / pores, but also penetrates the cellulose and hemicellulose portions between the fibers / pores. This is facilitated by the use of hot liquid, as it allows the cellulose and hemicellulose portions of the wood to expand as described above. Immersion of the wood substrate in hot salt water results in the formation of wood particles with salt dispersed throughout the particle. The dispersion of salt throughout the particles of the present invention is advantageous, for example, compared to simply coating the surface of the particle with salt. For example, by dispersing salt throughout the particle, the particles of the present invention can retain a higher amount of salt compared to particles that are simply coated with salt. Furthermore, the dispersion of salt throughout the particle means that the beneficial properties of the salt described herein can be exhibited throughout the particle, for example, in terms of resistance to decomposition and resistance to freezing. Thus, by dispersing salt throughout the filler particles of the present invention, the beneficial properties associated with salt impregnation are enhanced.

[0088] The dipping method in the present invention is different from coating in which only the surface of the particle is coated with little penetration into the inner part of the particle.

[0089] Thus, in the filler particles of the present invention, the salt is dispersed (substantially or completely) throughout the particle, or, in other words, the entire particle (or whole or all) is impregnated with the salt.

[0090] In some preferred embodiments, the soaking step is for about 5-60 minutes, preferably about 5-10, 10-15, 15-20, 20-25, 25-30, 30-35, 35-40, 40-45, 45-50, 50-55, or 55-60 minutes. In some embodiments, the soaking step is for at least 10 minutes, at least 15 minutes, or at least 20 minutes, more preferably at least 10 minutes. In some embodiments, the soaking step is for about 10-40 minutes, preferably about 15-35 or 20-35 minutes, more preferably about 30 minutes.

[0091] The method for producing filler particles of the present invention may further include, for example, a step of polishing the surfaces of the filler particles after the drying step.

[0092] As used herein, "polishing" refers to the process of creating a smooth surface on the filler particles of the present invention by abrasion and / or mechanical stress / pressure. As well as a smooth surface, polishing results in rounding of any edges / vertices and corners present on the particle. As discussed elsewhere herein, this can have beneficial properties in terms of performance and in sealing pores to prevent water ingress during use.

[0093] Methods of polishing, for example polishing of wood, are well known in the art. For example, it is well known to smooth the surface of wood by sanding using sandpaper. Sanding can be done mechanically using a sander or a sanding machine with sandpaper attached. To round off the corners of cubes and / or to polish grains, a belt machine using sandpaper grade 200 can be conveniently used. A suitable machine is known as a wild belt sanding machine, for example the SANDTEQ-W-200 of the HOMAG group. "Sanding" and "sanding" are used synonymously herein.

[0094] Another method of abrading the filler particles of the present invention is to subject the particles to multiple cycles of abrasion (e.g., 20,200 or 40,200 cycles) using an abrasion simulation device, such as a Lisport (i.e., Lisport Classic) abrasion simulation device.

[0095] The polishing step thus results in the production of filler particles of the invention having a smooth or polished surface, which reduces the water absorption of the filler particles, which is advantageous since water absorption is associated with the degradation of filler particles made of organic materials.

[0096] Without wishing to be bound by theory, it is understood that reduced water absorption may be achieved by blocking the pores of the particles (or more specifically the pores of the wood from which the particles are constructed) through the sanding process. Thus, the sanding step may seal a portion of the outer pores of the filler particles of the present invention.

[0097] Methods for obtaining wood particles (e.g., for use in salt treatment processes) are known in the art. For example, wood particles can be obtained by wood milling. Alternatively, wood particles can be obtained by cutting wood particles from wooden planks or veneers. Wooden planks and veneers can be cut using one or more well-known bladed tools, such as saws, e.g., scroll saws, hack saws, jig saws, circular saws, miter saws, reciprocating saws, or trimming saws. Most suitably, a band saw (e.g., a Shpatchbond Sag HBS261) can be used to cut the wooden planks to size. If necessary, a guillotine cutter can be used to precisely cut the particles (e.g., after cutting using a powerful instrument such as a band saw), and the spacing of the blades of the guillotine cutter can be adjusted to achieve the desired dimensions of the wood particles cut from the planks. Thus, a band saw can be used to produce wood of the desired grain size in two dimensions, and then the grains themselves can be produced by cutting to the desired grain size in the third dimension using a guillotine.

[0098] In the present invention, wood is generally a preferred example of cellulose and / or hemicellulose particles, therefore the above method also applies to obtaining particles made of other cellulosic and / or hemicellulose materials.

[0099] In a further aspect, the present invention provides a method for producing wood infill particles for artificial turf, the method comprising cutting wood into particles having a diameter of about 512 mm per particle. 3 (Preferably 1 to 8 mm 3), which particles are rectangular, preferably cubic, and then sanding (grinding) the cut particles to round their corners. The preferred features of the particles and cutting and grinding methods described elsewhere herein apply mutatis mutandis to this aspect of the invention.

[0100] In the present invention, wood is generally a preferred example of cellulose and / or hemicellulose particles. The above method therefore also applies to the production of particles made of other cellulosic and / or hemicellulose materials for artificial turf.

[0101] In embodiments, the rounded particles are up to about 512, 500, 400, 343, 300, 216, 200, 175, 125, 120, 115, 110, 105, 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, or 10 mm. 3 The rounded particles have a volume of at least about 0.001, 0.008, 0.01, 0.1, 1, 2, 3, 4, or 5 mm. 3 Preferably, the volume of the rounded particles is about 0.008 mm. 3 ~Approx. 64mm 3 , or about 0.008 mm 3 ~approx. 125mm 3 More preferably, the volume of the rounded particles is about 0.1 mm 3 ~approx. 125mm 3 Most preferably, the volume of the rounded particles is about 0.5 mm 3 ~Approx. 64mm 3 , for example, about 1 mm 3 ~ approx. 10 or 20 mm 3 , especially about 8 mm 3 Volume should be understood as the size of a particle measured or calculated from its dimensions; the volume of a particle is not reduced merely because it may contain pores (i.e., voids). Thus, a preferred particle, each of which is a 2 mm cube, may be 8 mm 3Preferably, the rounded particles have a volume of about 0.001 mm. 3 ~Approx. 512mm 3 , more preferably about 0.008 mm 3 ~approx. 125mm 3 , more preferably about 1 mm 3 ~Approx. 64mm 3 , more preferably about 1 mm 3 ~approx. 27mm 3 It has a volume of

[0102] The rounded particles described above can be impregnated with salt (eg, by the impregnation method described elsewhere herein) to produce the filler particles of the present invention.

[0103] The terms "synthetic turf" and "artificial turf" are used interchangeably herein.

[0104] "Artificial turf infill" or "infill for artificial turf" means an infill suitable for (or suitable for use on) artificial turf, i.e., as part of an artificial turf system. "Artificial turf" means man-made, manufactured or synthetic turf suitable for sports activities. Examples of artificial turf include hybrid, first generation (1G), second generation (2G) and third generation (3G) turf. These terms are well known in the art and are described above.

[0105] The infill of the present invention is suitable for all artificial or synthetic surfaces. In a preferred embodiment, the infill of the present invention is suitable for use on first, second or third generation artificial turf, preferably third generation artificial turf.

[0106] Thus, in a further aspect, the present invention provides an artificial turf system comprising an artificial turf carpet comprising artificial turf fibers, and a plurality of infill particles of the present invention.

[0107] In a preferred embodiment, the plurality of infill particles are evenly distributed across the artificial turf.

[0108] In a preferred embodiment, the artificial turf system further comprises sand.

[0109] The artificial turf system can be any artificial turf system suitable for sports. In a preferred embodiment, the artificial turf system is an artificial turf system for (or suitable for) ball games, preferably association football or soccer.

[0110] In a preferred embodiment, the turf carpet includes a backing. The turf carpet may include (in addition to the artificial turf fibers) a primary backing and a secondary backing. In some embodiments, the primary backing is polypropylene (PP) and the secondary backing is polyurethane (PU) or latex.

[0111] The artificial turf carpet comprises artificial turf fibers. The terms "fiber" and "pile" are used interchangeably herein. The artificial turf fibers can be any fibers suitable for use as part of an artificial turf system. The artificial turf fibers can be monofilament fibers, fibrillated fibers, monofilament fibers with stems, or combinations thereof, preferably monofilament fibers. In a preferred embodiment, the artificial turf fibers include or consist of polypropylene, polyethylene, nylon (polyamide), or combinations thereof. In an embodiment, the artificial turf fibers have a height of about 25-70 mm. In a preferred embodiment, the artificial turf fibers have a height of about 25-30, 30-35, 35-40, 40-45, 45-50, 55-60, 60-65, or 65-70 mm. In a preferred embodiment, the artificial turf fibers have a height of about 30-50 mm, preferably about 40 mm.

[0112] In the artificial grass system of the present invention, the infill particles are distributed between the artificial grass fibers. In other words, the infill particles are arranged between the artificial grass fibers. Alternatively, the infill particles are distributed or arranged between the grains of the artificial grass fibers (i.e., the points where the fibers protrude from, emanate from, or are attached to the (underlying) artificial grass carpet). The infill particles can be arranged at any point between the fibers, for example, at any point between the fibers in the horizontal or vertical direction.

[0113] In one aspect, the invention provides a grass or turf floor or football pitch comprising a filler particle or a plurality of filler particles of the invention. In some embodiments, the grass or turf floor or football pitch (further) comprises sand.

[0114] The invention provides filler particles produced by any of the inventive methods disclosed herein, the filler particles having the characteristics of the inventive filler particles defined herein.

[0115] In a further aspect, the present invention provides the use of a filler particle of the present invention or a plurality of filler particles of the present invention as infill for artificial turf. In an embodiment, the artificial turf is third generation (3G) artificial turf.

[0116] The invention will now be further described in the following non-limiting examples, with reference to the following figures:

[0117] FIG. 1 provides a graphical representation of the data in Table 18.

[0118] FIG. 2 shows images of filler particles of the invention, each made of birch wood measuring 2×2×2 mm, with a salt content of 30.5% by weight. FIG. 2A shows new, unused filler particles. Note that these particles have a rough, salt-rich surface. FIG. 2B shows the same type of particles after subjecting the filler particles to 20,200 cycles on a Lisport (i.e., Lisport Classic) wear simulation machine. Note that the particles are visibly smooth, polished, and shiny. FIG. 2C shows particles of the same composition after subjecting the filler particles to 40,200 cycles on a Lisport (i.e., Lisport Classic) wear simulation machine. Note that the appearance of the particles is essentially unchanged compared to the particles in FIG. 2B.

[0119] Figure 3 shows the results of Example 4 - this is an image of the infill particles of the present invention (each made of birch wood, 2x2x2mm size, salt content 30.5% by weight) after 5 years on artificial turf in harsh weather conditions. As Figure 3 shows, the infill particles are still stable. EXAMPLES

[0120] Example 1 - Cutting wood planks to produce granules • Using a standard band saw (Spatchbond Sag HBS261) a 100x100x5000mm thick board was cut to 2mm in two dimensions. • A guillotine cutter with a cutting window and support of 500 x 30 mm was then used to precisely cut 2 x 2 x 2 mm cubes. Ten high performance blades were arranged with a gap of 2 mm between them, achieving a cutting speed of 100 m per minute.

[0121] Example 2 - Salting of wood particles to produce filler particles of the present invention Example 2A - Methodology and Results process 1. Add water to a large container. 2. Add salt to the water. 3. Incubate with heat (e.g., 75°C) until all salts are dissolved. 4. Add wood granules (particles) to the saltwater. 5. Soak for at least 15 minutes. 6. Drain off the water and collect the wet granules. 7. Place the wet granules on a table to dry.

[0122] Table 1 - "2mm granules" means granules with a particle size of 2 x 2 x 2 mm, and "1mm granules" means granules with a particle size of 1 x 1 x 1 mm. [Table 1]

[0123] measurement ● Density of 1mm wet granules: 0.63g / ml ● Density of 2mm wet granules: 0.67g / ml ● Density of salt: 1.25g / ml ● Density of 30% w / v salt solution: ○ 1.12g / ml (density of salt solution during mixing (mass / volume of 1 liter container)) 1.15g / ml (density at the start of the salting process) ○ 1.17g / ml (density of remaining water after removing wet salt treatment granules) Density of dried salt-free 2mm granules: 0.326g / ml ● Density of dried salt-treated 2mm granules: 0.426g / ml ● Density of dried salt-free 1mm granules: 0.264g / ml ● Density of dried salt-treated 1mm granules: 0.325g / ml ● Density of all plates: 0.62g / ml (weight / volume of 3mm plywood)

[0124] Comparison of salt water and volumetric residual water ● Salt water: ○ Volume = 5.8 liters, Density = 1.12 g / ml (5 liters of water and 1.25 liters of salt equals 5.8 liters of liquid) ● Residual water: ○ Volume = 3.8 liters Density = 1.17 g / ml (represents approximately 4% of the water evaporated) ● Water absorbed into the granules: ○ This gives 1.95 liters or 0.585 liters (736 grams) of salt. ● 3 liters of dry granules were added; dry mass before salting process = 960 grams, after soaking in brine = 1620 grams; difference 660 grams (ok compared to 736 grams given some evaporation and precipitation of salt).

[0125] Conclusion and Discussion All measurements show good salt saturation. • Increase in temperature results in faster dissolution of salt. • Smaller particles tend to agglomerate more, absorb more water and require longer drying.

[0126] Example 2B - Calculation of salt content in dried salted 2mm granules Volume % Calculation To calculate the volume percent of salt in the dried salted particles, the following formula can be used: (x)*density of salt + (1-x)*density of dry unsalted granules = density of dry salted granules where 100*x is the volume % of salt in the dry salted granule (i.e. the % of the total volume of the granule that is composed of salt).

[0127] Therefore, the following densities apply: Density of dried salt-free 2mm granules = 0.326g / ml Density of dried salt-treated 2mm granules = 0.426g / ml Density of salt = 1.25g / ml Putting the above values ​​into the formula, we get: (x)*1.25+(1-x)*0.326=0.426 Therefore, x = 0.104. Therefore, the volume percent of salt in the dried salt-treated 2 mm granules is 10.4 volume percent.

[0128] Calculating mass percent (i.e. weight percent) [Table 2]

[0129] Therefore, the mass % of salt in the dry salted 2mm granule (i.e. the % of the total mass of the granule that consists of salt) is 0.130 / 0.426=0.305=30.5 mass % (i.e. weight %).

[0130] Example 2C - Calculation of salt content in dried salted 1mm granules Volume % Calculation The same formula as provided in Example 2B can be used. (x)*density of salt + (1-x)*density of dry unsalted granules = density of dry salted granules where 100*x is the volume % of salt in the dry salted granule (i.e. the volume % of the granule that is composed of salt).

[0131] Therefore, the following densities are applied to the formula: Density of dried salt-free 1mm granules: 0.264g / ml Density of dried salt-treated 1mm granules: 0.325g / ml Density of salt = 1.25g / ml From now on, (x)*1.25+(1-x)*0.264=0.325 Therefore, x = 0.0619. Therefore, the volume percent of salt in the dry salted 1 mm granules is 6.19 volume percent.

[0132] Calculating mass percent [Table 3]

[0133] Therefore, the mass % of salt in a dried salted 1 mm granule is 0.07738 / 0.325=23.8 mass % (i.e. weight %).

[0134] Example 3 - Sport Lab testing of the inventive filling material according to the performance requirements outlined in EN15330-1:2013 This example provides data from tests carried out by Sports Lab Ltd to confirm the suitability of the infill particles of the present invention for use on artificial turf. The tests presented below were carried out in accordance with BS EN15530-1:2013 (Surfaces for sports areas - Artificial turf and needle punch surfaces primarily intended for outdoor use).

[0135] BS EN15530-1:2013 is a document published by the British Standards Institution (BSI) in 2013, which provides a selection of tests to be carried out to meet the requirements of infills for artificial turf. Each test is itself described in detail in a separate published document, and each of these documents is designated with a specific "EN number" for clear and unambiguous identification. The EN numbers for each test carried out on the infill particles are given in Table 18.

[0136] The properties of the infill particles were also tested after simulated wear on a Lisport (i.e., Lisport Classic) wear simulation machine. The Lisport wear simulation machine comprises two heavy rollers with rounded 13 mm nylon studs. The machine traverses the sample (i.e., the artificial turf with infill) for a given number of cycles. The studs compress the sample, simulating the wear caused by years of sports use.

[0137] The particles tested consisted of birch wood pieces measuring 2x2x2 mm and had a salt content of 30.5% by weight as calculated in Example 2.

[0138] [Table 4]

[0139]

Table 5

[0140]

Table 6

[0141]

Table 7

[0142]

Table 8

[0143]

Table 9

[0144]

Table 10

[0145]

Table 11

[0146]

Table 12

[0147]

Table 13

[0148]

Table 14

[0149]

Table 15

[0150] [Table 16]

[0151] [Table 17]

[0152] Table 18 shows the results of screening a collection of filler particles of the present invention (birch wood, size 2x2x2mm) to determine particle size distribution. The results below confirm that the particles have the claimed particle size. For a graph of the data in Table 18, see Figure 1.

[0153] [Table 18]

[0154] [Table 19]

[0155] conclusion The products submitted were tested in accordance with the performance requirements outlined in EN15330-1:2013. Based on the test results, the products supplied met all performance requirements of EN15330-1:2013 for surfaces designed primarily for football.

[0156] Table 20 shows the technical results of the filler particles of the present invention. Each was made of birch wood with a size of 2x2x2 mm and was subjected to 40,200 cycles on a Lisport (i.e., Lisport Classic) wear simulation machine. An image of the particles after 40,200 cycles is shown in Figure 2C. It can be noted that the particles are visibly smooth, polished, and shiny. This method not only simulates abrasion, but is also a preferred method for providing particles of the invention with rounded corners, which may be preferred in some cases.

[0157] [Table 20]

[0158] [Table 21]

[0159] Example 4 - Stability of infill particles of the present invention in artificial turf A batch of the inventive filler particles made from birch wood, each having dimensions of 2x2x2mm and a salt content of 30.5% by weight, was placed on a patch of artificial grass outdoors in Stavanger, Norway, and left for a period of five years. After these five years, the batch of filler particles was analyzed and found to still be stable (Figure 3), which is quite impressive considering the harsh weather conditions in Stavanger.

[0160] Example 5 - Stability of filler particles of the present invention in soil A batch of filler particles of the present invention made of birch wood, each having dimensions of 2x2x2mm and a salt content of 30.5% by weight, was placed in outdoor soil in Stavanger, Norway. After three months, the soil was analyzed and it was found that the filler particles had completely decomposed in the soil.

Claims

1. 1. An artificial turf infill particle, the particle comprising a salt-impregnated substrate, the particle being free of thermoplastic material, the substrate comprising a cellulosic and / or hemicellulosic material, the particle having an area of ​​about 512 mm 3 3. A filler particle having a volume of up to 2000g, said particle having a salt content of at least 5% by weight, said salt being dispersed throughout said particle.

2. 10. The filler particle of claim 1, wherein the substrate consists essentially of cellulosic and / or hemicellulosic materials.

3. 10. The filler particle of claim 1, wherein the substrate is comprised of a cellulosic and / or hemicellulosic material.

4. The filler particle of any one of claims 1 to 3, wherein the particle is a manufactured filler particle.

5. A filler particle according to any one of claims 1 to 3, wherein the particle has a salt content of at least 20% by weight.

6. The particles are 0.001 mm 3 ~512mm 3 The filler particle according to any one of claims 1 to 3, having a volume of

7. The particles are 0.008 mm 3 ~125mm 3 The filler particle according to any one of claims 1 to 3, having a volume of

8. The particles are 1 mm 3 ~27mm 3 The filler particle according to any one of claims 1 to 3, having a volume of

9. 4. Filler particles according to any one of claims 1 to 3, wherein the particles have the shape of a cube, a rectangular prism, a sphere, an ellipsoid, a spheroid, an ovoid or a pyramid, preferably a cube, more preferably a cube with dimensions of 2mm x 2mm x 2mm.

10. 4. The filler particle of claim 1, wherein the particle has corners, the corners being rounded.

11. 4. The filler particle of any one of claims 1 to 3, wherein the particle has a smooth or polished surface.

12. The filler particles according to any one of claims 1 to 3, wherein the substrate is wood.

13. 13. The filler particle of claim 12, wherein the wood is natural wood or raw wood.

14. 14. The filler particle of claim 13, wherein the wood is softwood or hardwood.

15. 15. The filler particle of claim 14, wherein the wood is birch wood.

16. Filler particles according to any one of claims 1 to 3, wherein the particles are impregnated with an oil or a preservative.

17. 17. The filler particle of claim 16, wherein the oil is a natural oil and the preservative is a natural preservative.

18. 20. The filler particle of claim 17, wherein the oil is linseed oil.

19. 13. A plurality of filler particles, each filler particle being as defined in claim 1, said plurality of particles comprising more than one shape of filler particles and / or more than one size of filler particles.

20. 20. The plurality of filler particles of claim 19, wherein the two or more shapes are selected from the group consisting of cubes, rectangular prisms, spheres, ellipsoids, spheroids, ovoids, and pyramids.

21. 21. The plurality of filler particles of claim 19 or claim 20 comprising a first type of filler particles and a second type of filler particles, the first type of filler particles having a volume at least two or three times the size of the second type of filler particles.

22. 10. A method for producing the filler particles of claim 1, comprising the steps of: Particles comprising a substrate comprising cellulosic and / or hemicellulosic materials, the substrate being free of thermoplastic materials, the substrate being approximately 512 mm 3 immersing particles having a volume of up to 100 μm in a salt solution; and Optionally, drying the soaked particles.

23. The method of claim 22 further comprising polishing the particles.

24. 24. A method according to claim 22 or claim 23, wherein the salt solution is heated to at least 50°C, preferably to about 75°C.

25. 24. The method of claim 22 or 23, wherein the particles are maintained in the salt solution for at least 10 minutes.

26. An artificial turf system comprising an artificial turf carpet comprising artificial turf fibers and a plurality of infill particles according to any one of claims 1 to 3.

27. 27. The artificial turf system of claim 26, further comprising sand.

28. 24. The method of claim 22 or 23, obtaining particles prior to the immersion step; The step of obtaining particles may include cutting the cellulosic and / or hemicellulosic material to obtain particles having a diameter of about 512 mm per particle. 3 forming particles having a volume up to 100 mm and having a rectangular parallelepiped, preferably cubic, shape, and then polishing the cut particles to round their corners.

29. Use of a filler particle according to any one of claims 1 to 3 or a plurality of filler particles according to any one of claims 19 to 20 as infill for artificial turf.

Images