Multi-Purpose Sports Surface

This application claims the benefit of priority under 35 U.S.C. § 119(e) to U.S. Patent Application Provisional Application Ser. No. 63/641,466, entitled “MULTI-PURPOSE SPORTS SURFACE”, filed May 2, 2024, which is hereby expressly incorporated by reference herein for all purposes.

The present disclosure relates generally to the field of sports surface constructions. More particularly, the present disclosure relates to a synthetic turf system used for sport courts.

In the rapidly growing sport of pickleball, courts are traditionally constructed using hard surface materials like asphalt or concrete. While these materials are economically viable and durable, they come with a host of significant drawbacks. Firstly, the risk of injuries is heightened on such hard surfaces, with common injuries including soft tissue damage and fractures, which are especially problematic among older players. The inherent rigidity of materials like asphalt and concrete fails to adequately absorb shocks, potentially exacerbating joint and muscle injuries.

Furthermore, these impermeable surfaces contribute to elevated surface temperatures, negatively impacting player comfort and exacerbating the urban heat island effect, thereby contributing to local climate warming. Environmental impacts extend beyond temperature issues, as the impermeability of these materials hinders water percolation, leading to inefficient water management and runoff problems that carry pollutants to local water bodies.

From an aesthetic standpoint, traditional hard courts offer little appeal, providing a functional yet uninviting playing environment. Additionally, the playability of the game is affected on hard surfaces due to inconsistent ball bounce and the abrasive nature of these courts, which can lead to quicker wear of balls and equipment.

On the other hand, the typical synthetic turf infill system consists of a shock pad under artificial turf, using rubber, sand or a combination of these materials as infill. The standard synthetic turf infill system effectively manages shock attenuation. However, the unbound particles of the standard infill will absorb the force and move. Furthermore, the standard synthetic turf infill system does not have enough elasticity, potential energy, for a ball (e.g., a tennis ball or pickleball) to bounce to the required height.

Given these challenges with traditional pickleball court surfaces, there exists a clear need for a court surface that not only reduces injury risk, lowers surface temperatures, and provides environmental benefits through improved water management but also enhances aesthetic appeal and ensures consistent playability. The present invention has many of the same characteristics of standard synthetic turf systems while adding the element of elasticity or springiness that facilitates required ball bounce and playing characteristics.

The present disclosure envisages a synthetic turf covering for use in sports courts. The synthetic turf covering includes a foundation having a topside and a bottom side; a plurality of grass-like pile filaments attached to and extending upward from the topside of the foundation; and a particulate infill disposed between the grass-like pile filaments, where the particulate infill includes both elastic and inelastic particles bound with a suitable organic or inorganic binder.

In one embodiment, a portion of the grass-like pile filaments are above the bound infill in order to give it a more natural look of grass as well as provide cushioning. In another embodiment, the bound resilient particles of the infill provide a softer surface as well as shock attenuation and springiness.

In one embodiment, the foundation includes materials selected from the group consisting of ground, gravel, sand, rubber, and combinations thereof.

In one embodiment, the foundation is angled to facilitate drainage. In still further aspects, the disclosed playing surface assemblies can be permeable to moisture.

In one embodiment, the binder initiates a curing process upon hydration. The binder creates a bound infill material. Specifically, binding the particles allows the infill to absorb force making it a safer playing surface while allowing a return of the energy to the ball for proper bounce. The bound aspect gives the surface a sort of “trampoline” effect. In contrast, the typical turf infill system consists of a shock pad under turf, rubber, sand or a combination of these materials. The standard system effectively manages shock attenuation. However, the unbound particles absorb the force and transfer the energy from particle to particle via friction and infill movement. For example, as a system standard turf install does not have enough elasticity, potential energy, for a sports ball (e.g., a pickleball) to bounce to the required height.

In one embodiment, the sport surface is a sports court. In another embodiment, the sport surface is a pickleball court that provides adequate ball bounce from the surface. In another embodiment, the sport surface is a pickleball court that provides adequate cushioning for shock absorption, without adversely affecting the ball bounce height.

In one embodiment, the infill is bound by a suitable organic or inorganic binder. A typical organic binder is selected from at least one member of the group consisting of a phenolic resole resin or phenolic novolac resin, urethanes (for example polyol resins, e.g., phenolic resin, dissolved in petroleum solvents which are cross-linkable with a polymeric isocyanate using an amine catalyst), alkaline modified resoles set by esters, melamine, and furans. Typical inorganic binders include silicates, e.g., sodium silicate, phosphates, e.g., polyphosphate glass, borates, or mixtures thereof, e.g., silicate and phosphate. Typical binders for the present invention also may be selected from polymer/cement combinations and MDF cement.

In some embodiments, the infill layer coating composition includes a binder component and a particle component. The binder component may include a cementitious binder that includes Portland cement, such as white cement or grey cement, alone or in combination with one or more supplementary cementitious materials (SCMs), such as fly ash, metakaolin, pumice, natural pozzolan, slag, or silica fume. Alternatively, or in addition to the cementitious binder, the binder component may comprise a polymer binder, such as an acrylic binder that includes an acrylic resin and/or polymer. Other polymer binders include, but are not limited to, polyvinyl alcohol (PVA), alkyd resins, polyurethane, and other materials typically used to bind particles.

Some embodiments also include geopolymer binders or cements, hydraulic cements, supplementary cementitious materials (SCMs), hydraulic concrete mixtures, and solid concrete powders including microspheroidal glassy particles as defined herein. According to some embodiments, a geopolymer cement is used, which may include a cementitious reagent as disclosed herein. The geopolymer cement may further include an ambient cure reagent, and a solid or liquid hardener. An example geopolymer cement mixture may include 40-70 wt. % cementitious reagent, 15-25 wt. % ambient cure reagent, and 5-45 wt. % solid aggregate. Some embodiments also relate to geopolymer binders or cements, hydraulic cements, supplementary cementitious materials (SCMs), hydraulic concrete mixtures, and solid concrete powders including microspheroidal glassy particles as defined herein.

In the present invention, the term “geopolymer binder” or “geopolymer cement” relates to a mixture that sets and hardens due to polycondensation. The overall hardening process is known as the “geopolymerization” process. These reactions often occur at low temperatures. The term “geopolymer” includes a material in the dry state, obtained following the hardening of a mixture containing finely ground materials (i.e. generally an alumino-silicate source) and a saline solution (i.e. an activation solution), said mixture being capable of setting and hardening over time. The hardening of the geopolymer is the result of the dissolution/polycondensation of the finely ground materials of the geopolymeric mixture in a saline solution such as a high-pH saline solution (i.e. the activation solution).

According to an implementation a method of producing geopolymer-bound infill may include providing a geopolymer binder. The geopolymer binder may include a geopolymer precursor, magnesium oxide as an alkali activator. The method may further include mixing the geopolymer binder with water. The geopolymer precursor may include a material containing amorphous silicates of one or more of calcium, aluminum, and magnesium. The geopolymer precursor may include one or more of: slag cements; fly ash; metakaolin; fumed silica; and rice husks. The geopolymer binder may include between about 10% to about 95% of the geopolymer precursor by weight of the geopolymer binder. The magnesium oxide may include magnesium oxide calcined to exhibit a caustic magnesia activity neutralization time of between about 9 seconds to about 30 seconds using a 1.0N acetic acid. The magnesium oxide may exhibit a magnesium oxide purity from between about 75% to about 99%. The geopolymer binder may include between about 1% to about 50% magnesium oxide by weight of the geopolymer binder. The geopolymer binder may further include a co-alkali activator. The co-alkali activator may include one or more of: sodium silicate; potassium silicate; sodium metasilicate having a formula NaSiO; .nHO, where n=one of 5, 6, 8, 9; sodium hydroxide; sodium aluminate; sodium carbonate; hydrated lime; quick lime; dolime; hydrated dolime; potassium oxide; lithium oxide; alumina; iron oxide; nickel oxide; copper oxide; sodium lactate; ordinary Portland cement; and calcium gluconate. The geopolymer binder may include an amount of co-alkali activator that is equal to or less than an amount of the magnesium oxide by weight.

In one embodiment, the geopolymer binder composition is a precursor composition of a geopolymer. In other words, it comprises ingredients (e.g., aluminosilicate, alkaline silicate, water, alkaline base, metakaolin, etc.) which geopolymerize together (by polycondensation) to form a geopolymer, also known as geopolymer material, as defined in the invention.

In one embodiment, the geopolymer binder is an aluminosilicate geopolymer composition. In another embodiment, the geopolymer binder is a geopolymer composition comprising water, silicon (Si), aluminum (Al), oxygen (O), and at least one element selected from potassium (K), sodium (Na), lithium (Li), cesium (Cs), and calcium (Ca), and preferably selected from potassium (K) and sodium (Na). In another embodiment, the geopolymer binder composition may comprise at least an aluminosilicate, an alkali metal silicate, water, and optionally an alkaline base. In one embodiment, the aluminosilicate can be selected from metakaolins (i.e. calcined kaolins), fly ash, blast furnace slag, swelling clays such as bentonite, calcined clays, any type of compound comprising aluminum and silica fume, zeolites, and a mixture thereof.

In the invention, “metakaolin” means a calcined kaolin or a dehydroxylated aluminosilicate. It is preferably obtained by dehydration of kaolin or of a kaolinite. This dehydration is conventionally obtained by calcination.

In one embodiment, the geopolymer composition may comprise from 5% to 50% by weight approximately of aluminosilicate, and preferably from 10% to 35% by weight approximately of aluminosilicate, relative to the total weight of the geopolymer composition.

In one embodiment, the binder can be polymer based or cementitious materials, such as Portland cement, silica fume (microsilica), fly ash, lime, etc. In one embodiment, the binder is powdered or liquid solution polymer binders that are designed to bind soil and other particles such as DirtGlue® polymers produced by GES/Global Environmental Solutions.

The term “particle” as used herein refers to any shaped single element of the materials and volume specified. The mean size of the particles refers to the largest dimension of a given particle and the mean is the arithmetic mean. Preferably the mean size of the particles will lie between 0.5 mm and 5 mm and preferably no particles will have dimensions greater than 10 mm. Alternatively, the particles may be defined in terms of mesh size as defined by EN 933-1 In one embodiment at least 90% by weight of the particles are retained by a 0.5 mm sieve, while at least 90% of particles will pass through a 5 mm sieve. In one embodiment, the particulate infill comprises particles with a granule size ranging from about 0.2 mm to 6 mm. In another embodiment, the particulate infill comprises particles with a granule size ranging from about 0.5 mm to 5 mm. In another embodiment, the particulate infill comprises particles with a granule size ranging from 1 mm to 5 mm.

The particles may be of any shape, both defined and undefined, similar, different or random. The particle shape will depend on the process of manufacture and on the intended functional performance. In certain embodiments, one or a combination of any of spherical, cuboidal, cylindrical, lozenge or lenticular shapes may be chosen.

In one embodiment, the particulate infill is applied to a depth that is between 10% and 95% of the average height of the grass-like filaments.

The height of the infill may vary by design and also the pile height. A typical infill height is from about 10 mm to about 50 mm. The infill height is designed to provide adequate weight of the infill per square area of the infill to provide a stabilized playing surface.

In one embodiment, the particulate infill particles are applied at about ¼ lbs to about 9 lbs per square foot, depending on specific infill materials bulk density. For example, a particulate infill that includes cork particles will have a lower bulk density than an all sand infill.

As indicated above, the infill may comprise various relative amounts of binder, infill particle material and further optional components as determined by the required properties. In one embodiment, the infill comprises from 50 to 99 wt % of the particle material and from 1 to 50 wt. % binder, from 2 to 15 wt. % binder, more preferably from 5 wt % to 10 wt % binder.

In certain embodiments, the composition comprises a mixture of from 25 to 95 volume percent resilient particles and from 5 to 75 volume percent fine sand interspersed among the pile elements, wherein said resilient particles comprise cork granules or rubber particles, wherein said rubber is natural rubber or a synthetic rubber selected from the group consisting of styrene-butadiene rubber, butyl rubber, cis-polyisoprene rubber, neoprene rubber, nitrile rubber and urethane rubber.

In one embodiment, the particulate infill comprises materials selected from the group consisting of sand, rubber granules, cork granules, polymer beads, ceramic beads, zeolite powder, bio-based material, crushed coral, diatomaceous earth, vermiculate particles, soil, and combinations thereof.

A “bio-based material” as used herein is a material wholly or partly derived from materials of biological origin. In particular, bio-based materials can be materials which predominantly (>50 wt. %) comprise or consist of biodegradable and/or compostable materials, and, in some embodiments, materials only consisting of compostable materials. Examples include cork particles and fragments of fruit pits and nut shells.

In one embodiment, the particulate infill substantially comprises cork particles mixed with liquid or dry powdered binder, which cure upon hydration. In one embodiment, the particulate infill is substantially homogeneous.

The present disclosure also envisages a method for installing a synthetic turf covering on a sports court. The method includes the steps of providing a foundation with a topside and a bottom side; attaching a plurality of grass-like pile filaments to the topside of the foundation such that the filaments extend upward; dispersing a particulate infill among the grass-like pile filaments, the particulate infill comprising elastic and inelastic particles and a binder; and applying a liquid to the particulate infill to initiate curing of the binder.

In one embodiment, the particulate infill is applied to a depth that is between 10% and 95% of the average height of the grass-like filaments.

In one embodiment, the foundation comprises materials selected from the group consisting of ground, gravel, sand, rubber, and combinations thereof.

In one embodiment, the particulate infill further comprises materials selected from the group consisting of sand, rubber granules, cork granules, polymer beads, ceramic beads, zeolite powder, crushed coral, diatomaceous earth, vermiculate particles, soil, and combinations thereof. In another embodiment, the particulate infill further comprises materials selected from the group consisting of cork, hemp, bamboo, and coconut coir (fiber).

In one embodiment, the particulate infill is substantially homogeneous.

In one embodiment, the grass-like pile filaments are made from materials selected from the group consisting of polyethylene, nylon, and polypropylene.

In one embodiment, the backing layer comprises a woven or non-woven fabric coated with a rubber-type material.

In one embodiment, the playing surface assembly has a surface impact attenuation (gmax) ranging from 100 to 250. In another embodiment, the playing surface assembly has a surface impact attenuation (gmax) ranging from 150 to 250. In another embodiment, the playing surface assembly has a surface impact attenuation (gmax) at least 100. In another embodiment, the playing surface assembly has a surface impact attenuation (gmax) at most 200. In another embodiment, the playing surface assembly has a surface impact attenuation (gmax) ranging from 50-200.

In one embodiment, the Gmax value of the playing field for lower impact sports would be selected to be within a range of about 115-200, with a more preferred range being about 135-165. For higher impact sports, a preferred Gmax value of the playing field would be about 90-160, with a more preferred range being about 100-145. In another embodiment, the Gmax value of the playing field be selected to be within a range of about 50 to about 160. In another embodiment, the Gmax value of the playing field be selected to be within a range of about 80 to about 145. In another embodiment, the Gmax value of the playing field be selected to be within a range of about 115 to about 200. In another embodiment, the Gmax value of the playing field be selected to be within a range of about 135 to about 165.

In one embodiment, the playing surface assembly has drainage, according to ASTM BS 7044 Method 4 (Determination of infiltration rate-buffered ponding-type infiltrometer) of greater than 10, 15, 20 inches of water per hour (in/hr) or more, preferably, greater than 25 in/hr. In another embodiment, the playing surface assembly has drainage of 10-60 in/hr. In another embodiment, the playing surface assembly has drainage of at least 5, 10, 15, 20 or more in/hr.

In one embodiment, the backing layer is flexible enough to conform to the topography of the underlying foundation.

In the following detailed description of exemplary embodiments of the disclosure, specific exemplary embodiments in which the disclosure may be practiced are described in sufficient detail to enable those skilled in the art to practice the disclosed embodiments. For example, specific details such as specific method orders, structures, elements, and connections have been presented herein. However, it is to be understood that the specific details presented need not be utilized to practice embodiments of the present disclosure. It is also to be understood that other embodiments may be utilized and that logical, architectural, programmatic, mechanical, electrical and other changes may be made without departing from general scope of the disclosure. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims and equivalents thereof.

References within the specification to “one embodiment,” “an embodiment,” “embodiments”, or “one or more embodiments” are intended to indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. The appearance of such phrases in various places within the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Further, various features are described which may be exhibited by some embodiments and not by others. Similarly, various requirements are described which may be requirements for some embodiments but not other embodiments.

Ranges can be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. Optionally, in some aspects, when values are approximated by use of the antecedent “about,” it is contemplated that values within up to 15%, up to 10%, up to 5%, or up to 1% (above or below) of the particularly stated value can be included within the scope of those aspects. Similarly, in some optional aspects, when values are approximated by use of the term “substantially” or “substantially equal,” it is contemplated that values within up to 15%, up to 10%, up to 5%, or up to 1% (above or below) of the particular value can be included within the scope of those aspects. As used herein, the terms “optional” or “optionally” mean that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

illustrates an exemplary embodiment of a synthetic turf covering or sport surfacing, in accordance with an embodiment of the present disclosure. In an embodiment, the synthetic turf coveringcomprises multiple layers and components, where each layer and component contribute to the overall performance and utility of the covering.

In accordance with an embodiment of the present disclosure the synthetic turf coveringis provided on a foundation layer. The foundation layeris a structural base and is composed of various materials that may include, but are not limited to, bare ground, paving, gravel, sand, rubber, or a combination thereof with stones or similar aggregates. In accordance with one or more embodiments, the aforementioned materials are selected to ensure appropriate support and drainage for the synthetic turf covering. In alternative embodiments, foundation layermight comprise engineered composites designed to optimize load distribution and water management. Options could include recycled materials, geotextiles, and advanced polymers that complement or replace the traditional materials to provide enhanced performance characteristics.

As used herein, the “performance characteristics” of the playing surface assembly can include, for example and without limitation, g-max, head injury criterion (HIC), Advanced Artificial Athlete (AAA) (e.g., vertical deformation, force reduction, and energy restitution), shear vane, rotational traction, and combinations thereof. Other exemplary performance characteristics of the playing surface assembly include moisture content (measured as volumetric water content), friction (measured in accordance with the procedure of ASTM F1015-03), and ball bounce and pace, which can be determined using conventional video analysis in accordance with conventional methods. Optionally, a playability assessment tool can measure certain performance properties of playing surfaces as disclosed herein. The playability assessment tool can determine a quantifiable playability score for fields (e.g., sports fields, surfaces or turf). The playability of a field, or sports surface, relates to the way in which objects and players interact with the surface. Various factors, including the surface hardness, stability, strength, moisture, composition, and other factors can affect the overall playability of a surface.