IMPROVED ARTIFICIAL TURF FILL COMPOSITION

Abstract

An infill composition for artificial turf comprising particles comprising 20% and 40% by weight of natural rubber relative to the particles of the composition, at least one mineral filler, one plant filler, and at least one crosslinking agent, wherein the plant filler is cactus fiber or powder.

Description

IMPROVED ARTIFICIAL TURF FILL COMPOSITION TECHNICAL SECTOR The present invention relates to infill compositions for artificial turf that do not generate microplastics during their useful life. BACKGROUND OF THE INVENTION Artificial turf has emerged as a versatile and durable solution for numerous applications, from sports fields to recreational areas and landscaping. The evolution of this technology has been driven by the constant pursuit of replicating the qualities of natural grass. In this context, artificial turf infill has become a crucial component for improving the stability, safety, and aesthetics of these synthetic surfaces. To date, the predominant infill for artificial turf fields is obtained primarily from recycled tires, using petroleum-derived rubbers known as Styrene-Butadiene Rubber (SBR). SBR is known for its durability, abrasion resistance, and ability to withstand harsh environmental conditions, making it suitable for use in products requiring strength and flexibility. Among the measures adopted by the European Union to limit the manufacture and sale of products that generate polluting particles in the air and water, the restriction on granular infill used in synthetic sports surfaces stands out. The European Commission identifies this type of infill as "the largest source of intentional microplastics in the environment." These microplastic particles originate from the degradation of this synthetic infill. Among the products affected by the restriction, the granular infill used in synthetic sports surfaces stands out, recognized by the European Commission as "the largest source of intentional microplastics in the environment." Given this situation and with the aim of adopting more sustainable practices, the urgent need to develop alternatives has arisen. In response, the goal is to create a substitute product made from natural rubber, thus helping to mitigate the environmental impact associated with microplastics derived from conventional infill systems in artificial turf fields. EXPLANATION OF THE INVENTION The present invention focuses on preventing the generation of microplastics in the environment caused by the degradation of artificial turf fields. The formulated composition consists exclusively of environmentally friendly and sustainable elements, thus addressing the environmental problem associated with microplastic generation. The invention relates to an artificial turf filler composition comprising particles comprising between 20% and 40% by weight of natural rubber relative to the composition particles, at least one mineral filler, one vegetable filler, and at least one crosslinking agent, wherein the vegetable filler is cactus fiber or powder. PREFERRED EMBODIMENT OF THE INVENTION The first aspect of the invention relates to an artificial turf filler composition comprising particles comprising between 20% and 40% by weight of natural rubber relative to the composition particles, at least one mineral filler, one vegetable filler, and at least one crosslinking agent, wherein the vegetable filler is cactus fiber or powder. Surprisingly, the presence of a crosslinking agent in the composition particles not only contributes to their structural stability but also significantly improves their mechanical strength and durability under the conditions of use in artificial turf installations. This controlled pre-vulcanization of natural rubber results in more cohesive particles with a lower tendency to degrade, reduced dust emissions, and greater preservation of their physical properties over time. All of this is achieved without compromising the material's biodegradability, and it also prevents the generation of microplastics at the end of its useful life. Surprisingly, the incorporation of cactus fiber or powder yields particles with a bio-based carbon content, determined by radiocarbon (C14) analysis, exceeding 85%, as well as rapid biodegradation exceeding 30%, assessed according to OECD Guide 301 B: CO₂ Evolution (Modified Sturm Test). In the preferred embodiment, the cactus fiber or powder is derived from the prickly pear cactus (Opuntia ficus-indica). Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by a person skilled in the art to which this invention pertains. Similar or equivalent methods and materials to those described herein may also be used in the practice or testing of the present invention. The term "particles" refers to an individual portion or unit of the filler composition. Likewise, the terms particle, granule, and pellet are used interchangeably. The term "natural rubber," also known as latex, refers to rubber composed primarily of isoprene polymers derived from natural sources. Natural rubber is produced by a polymerization reaction that occurs in nature, such as in the Hevea brasiliensis tree, and is obtained as an aqueous solution by extraction from the bark. From a chemical standpoint, natural rubber is a natural polymer. The term "mineral filler" refers to inorganic solid materials, such as fine particles or mineral powders, used to modify the physical, chemical, or mechanical properties of the resulting composite material. These compounds, when mixed with polymers, can improve their strength, increase their density, and, for example, in the specific case of the invention, when mixed with rubber, act as a rubber elasticity reducer. The term "crosslinking agent" refers to a chemical substance that allows bonds to form between polymer chains, generating a more stable three-dimensional structure. In another preferred embodiment of the composition of the invention, the composition particles comprise between 35 and 70% mineral filler by weight. The mineral filler contained in the composition particles of the invention is selected from the group consisting of calcium carbonate, silica, talc, kaolin, titanium dioxide, barite, mica, bentonite, wollastonite, or mixtures thereof. In another preferred embodiment of the composition of the invention, the composition particles comprise between 0.5 and 5% crosslinking agent by weight relative to the composition particles. In the most preferred embodiment, the composition particles comprise between 0.5 and 3% crosslinking agent by weight relative to the composition particles. The crosslinking agent contained in the composition particles of the invention is selected from the group of sulfur, organic peroxides, or mixtures thereof. Preferably, the crosslinking agent contained in the particles is sulfur. In another preferred embodiment of the invention, the particles of the composition of the first aspect of the invention comprise between 5 and 25% by weight of plant material, preferably comprising between 5 and 20% by weight of the particles of the composition. Additionally, the particles of the composition of the first aspect of the invention also comprise an auxiliary additive. The term "auxiliary component" refers to an additive that facilitates the handling and mixing of the substances in the composition. In this particular case, the auxiliary component refers to metal oxides. In a more preferred embodiment, the auxiliary component is zinc oxide, calcium oxide, or magnesium oxide. In the most preferred embodiment, the auxiliary component is zinc oxide. The auxiliary component functions as a process aid, facilitating the mixing of the composition and achieving the appropriate particle size, thus facilitating the overall mechanical process. In another more preferred embodiment of the invention, the particles of the composition of the first aspect of the invention comprise between 0.1 and 5% by weight of auxiliary component relative to the particles of the composition. In the most preferred embodiment of the invention, the particles of the composition of the first aspect of the invention comprise between 0.2 and 2% by weight of auxiliary component relative to the particles of the composition. Additionally, the particles of the composition according to the first aspect of the invention comprise a metallic stearate. The incorporation of this metallic stearate is intended to improve the processability of the composition, acting as an internal lubricant and facilitating both the handling and the homogeneous mixing of the various components. It also contributes to better flowability and stability of the material during its processing in different types of industrial machinery, reducing friction and energy consumption. In a preferred embodiment, the metallic stearate is selected from zinc stearate, calcium stearate, or magnesium stearate. In the most preferred embodiment, the metallic stearate is calcium stearate. In another more preferred embodiment of the invention, the particles of the composition of the first aspect of the invention comprise between 2 and 10% by weight of metallic stearate relative to the particles of the composition.In the most preferred embodiment of the invention, the particles of the composition of the first aspect of the invention comprise between 5 and 10% by weight of metallic stearate relative to the particles of the composition. Certain ranges are presented with numerical values ​​preceded by the term "approximately." The term "approximately" is used in this document to provide literal support for the exact number it precedes, as well as for a number close to or approximately the number preceding the term. To determine whether a number is close to or approximately the number specifically recited, the unrecited close or approximate number may be a number that, in the context in which it is presented, provides the substantial equivalent of the specifically recited number. In the most preferred embodiment, the composition of the first aspect of the invention has a density between 0.95 and 3 g / cm3, preferably between 0.95 and 1.5 g / cm3. In a preferred embodiment, the particles of the composition according to the first aspect of the invention have a size between 1 and 8 mm, more preferably between 1.5 and 4.5 mm. The particle size is determined by methods known and customary in the field of art, for example, by sieving. In the compositions of the invention, at least 40% by weight of the components is of renewable origin. The term "renewable origin" refers to those that come from natural sources that can be regenerated or replaced in a relatively short period of time. Some examples of these materials are naturally occurring polymers, minerals, or products resulting from the agricultural industry, such as nut shells or similar materials, wood, or natural fibers, such as cotton, flax, or hemp. Having adequately described the nature of the present invention, as well as the means of implementing it, it is not considered necessary to extend its explanation so that any person skilled in the art may understand its scope and the advantages derived from it. It is specified that, in its essence, it may be carried out in other embodiments that differ in detail from those provided by way of example, and that these are also covered by the protection sought, provided they do not alter, change, or modify its fundamental principle. EXAMPLES By way of illustration, but not limitation, different embodiments of infill compositions for artificial turf are described below, as well as the processes used in their preparation. These descriptions provide a more detailed and specific view of the formulations and methods, serving as representative, but not restrictive, examples of the wide variety of compositions and procedures that can be applied in the manufacture of sustainable infills for synthetic sports surfaces. The mixing of the compositions described in the previous examples is carried out in a kneader or Banbur-type mixer, in which the different components are progressively incorporated. First, the natural rubber is introduced for mastication, a process that lasts for 3 to 5 minutes. Next, the fillers are added, and in a final stage, the sulfur, zinc oxide, and pigment are incorporated. The mixture is subjected to shearing and pressure for approximately 15 minutes, reaching a temperature between 140°C and 146°C, thus ensuring adequate homogenization of the composition. Sheets or plates of material are then obtained using a calender or rollers, and subsequently crushed to obtain particles of the desired size.

Claims

1. An infill composition for artificial turf comprising particles containing between 20% and 40% by weight of natural rubber relative to the particles of the composition, at least one mineral filler, one plant filler, and at least one crosslinking agent, wherein the plant filler is cactus fiber or powder.

2. The composition according to the preceding claim, wherein the particles of the composition further comprise an auxiliary component.

3. The composition according to any of the preceding claims, wherein the crosslinking agent is sulfur.

4. The composition according to any of the preceding claims, wherein the particles of the composition contain between 0.5% and 5% by weight of a crosslinking agent relative to the particles of the composition.

5. The composition according to any of the preceding claims, wherein the auxiliary component is zinc oxide. 6.The composition according to any of the preceding claims, wherein the particles of the composition further comprise a metallic stearate.

7. The composition according to any of the preceding claims, wherein the particles of the composition comprise between 0.1 and 5% by weight of an auxiliary component relative to the particles of the composition.

8. The composition according to any of the preceding claims, wherein the particles of the composition comprise between 35 and 70% by weight of mineral filler relative to the particles of the composition.

9. The composition according to any of the preceding claims, wherein the particles of the composition comprise between 5 and 25% by weight of plant-based filler relative to the particles of the composition. 10.The composition according to any of the preceding claims, wherein the mineral filler is selected from calcium carbonate, silica, talc, kaolin, titanium dioxide, barite, mica, bentonite, wollastonite, or mixtures thereof.

11. The composition according to any of the preceding claims, wherein the composition has a density between 0.95 and 3 g / cm³.

12. The composition according to any of the preceding claims, wherein the particles of the composition have a size between 1 and 8 mm.

13. The composition according to any of the preceding claims, wherein at least 40% by weight of the components of the composition are of renewable origin.

14. The composition according to any of the preceding claims, wherein the particles of the composition further comprise a coloring agent.