Patent Application
20190153679
The invention relates to artificial turf, in particular to artificial turfs with infill and also infill for artificial turf.
Artificial turfs are known as a carpet structure resembling natural grass. The structure consists of a fabric to which fibers are tufted and fixed at the bottom side of the fabric. The fibers are monofilamented or twisted yarns of polyethylene or other thermoplastic materials. The fabrics are woven goods made of polypropylene and the fixing material which glues the fibers to the fabric are mixtures of SBR latices and fillers such as calcium carbonate or polyurethane-based adhesives.
Artificial turfs are used as sports fields whereas the carpets are laid onto a substructure of rubber granules acting as a shock damping layer or onto a substructure that comprises an elastic layer (e-layer). The carpet structure is filled with sand and rubber granules in order to keep the structure in place so that the carpet does not slip and the fibers stay in an upright position. The filling material is also referred to as infill or infill material. Typically in use is SBR-rubber or EPDM-rubber, both elastomeric materials in irregularly granulated form. The SBR-rubber is commonly sourced from used tires.
An advantage of using artificial turf is that it eliminates the need to care for a grass playing or landscaping surface, like regular mowing, scarifying, fertilizing and watering. Watering can be e.g. difficult due to regional restrictions for water usage. In other climatic zones the re-growing of grass and re-formation of a closed grass cover is slow compared to the damaging of the natural grass surface by playing and/or exercising on the field. Artificial turf fields though they do not require a similar attention and effort to be maintained, may require some maintenance such as having to be cleaned from dirt and debris and having to be brushed regularly. This may be done to help fibers stand-up after being stepped down during the play or exercise. Throughout the typical usage time of 5-15 years it may be beneficial if an artificial turf sports field can withstand high mechanical wear, can resist UV, can withstand thermal cycling or thermal ageing, can resist inter-actions with chemicals and various environmental conditions. It is therefore beneficial if the artificial turf has a long usable life, is durable, and keeps its playing and surface characteristics as well as appearance throughout its usage time.
The infill of synthetic turfs plays a predominant role concerning the mechanical properties of the complete turf structure. These properties determine the damping of a bouncing ball and running or jumping athletes. It is also desirable that the uppermost structure of a turf would not cause injuries of the athletes, such as burns, scratches, skin abrasions, etc. Filling a synthetic turf only with sand would have an unpleasant effect of energy-sapping, comparable to running on dry sand on a beach. To avoid such uncomfortable attitudes infill systems are commonly in use. At least two layers built up such infill systems, whereas the sand layer is laid first on top of the carpet topping (the opposite side of the backing) and a second layer or elastomeric material laid onto the sand. The elastomeric material normally consists of ground rubber, whereas the particles are coarser than the sand grains. The thickness of an infill system is such that only a small proportion of the grass fibers exceed the infill layer in height. The complete structure then resembles freshly mowed natural grass.
The FIFA (Federation Internationale de Football Associaton) has set up quality standards in their ‘Quality Concept for Football Turf, Handbook of Requirements, January 2012 Edition.’ In this handbook, the standards are described as well as the test methods. For synthetic turf infill systems, the following holds:
According to the FIFA standards the tests are carried out with a so-called advanced artificial athlete—Triple A, a Lisport wear tester and a rotational resistance tester. Artificial turf or artificial grass is surface that is made up of fibers which is used to replace grass. The structure of the artificial turf is designed such that the artificial turf has an appearance which resembles grass. Typically, artificial turf is used as a surface for sports such as soccer, American football, rugby, tennis, golf, for playing fields, or exercise fields. Furthermore, artificial turf is frequently used for landscaping applications.
Artificial turf may be manufactured using techniques for manufacturing carpets. For example, artificial turf fibers which have the appearance of grass blades may be tufted or attached to a backing. Often times artificial turf infill is placed between the artificial turf fibers. Artificial turf infill is a granular material that covers the bottom portion of the artificial turf fibers. The use of artificial turf infill may have a number of advantages. For example, artificial turf infill may help the artificial turf fibers stand up straight. Artificial turf infill may also absorb impact from walking or running and provide an experience similar to being on real turf. The artificial turf infill may also help to keep the artificial turf carpet flat and in place by weighting it down.
United States patent application US 2010/0151158 discloses a method for recycling synthetic turf that includes agglomerating a plurality of synthetic turf fragments and extruding the agglomerated material. The method produces a recycled material for use as infill in a synthetic turf. The agglomerate is extruded and may be in a spherical, cylindrical, oval, or football shaped. The pellets may also be of an irregular shape. The irregular shape may be used to aid tight packing of the granules.
The invention provides for an artificial turf surface, a method, and the use of an agglomerate as infill for artificial turf. Embodiments are given in the dependent claims.
Examples may provide for an artificial turf infill that is at least partially made from an agglomerate comprising one or more non-elastomeric thermoplastics. The agglomerate is formed into irregularly shaped grains. A “grain” as used herein encompasses a small part or portion of a material that is hard.
Normally, non-elastomeric thermoplastics would be too hard and rigid to use as an artificial turf infill. However, forming them into grains that have fibrous extensions makes them flexible. When the grains are distributed in the pile of the artificial turf, the grains have a tendency to pack loosely because of the fibrous extensions. This produces voids or free space between the grains which makes the resultant infill more elastic although it has been manufactured from non-elastomeric thermoplastics.
In various examples, the agglomerate may be formed my one or more non-elastomeric thermoplastics and an additional additives such as a pigment powder.
In some examples, the artificial turf infill that is at least partially made from an agglomerate of at least two non-elastomeric thermoplastics.
In other examples, material used to form the artificial turf infill is provided as an agglomerate. An extrusion process or an agglomeration process is then used to form the material into the grains with fibrous extensions.
In one aspect, the invention provides for an artificial turf surface comprising an artificial turf carpet with a pile. The artificial turf carpet comprises a backing. The artificial turf carpet further comprises artificial grass fibers. The artificial grass fibers are tufted into the backing. The artificial turf grass fibers form the pile. The artificial grass fibers are secured to the backing.
The artificial turf surface further comprises an artificial turf infill which is distributed within the pile. The artificial turf infill may also be described as being distributed between the artificial grass fibers. The artificial turf infill comprises irregularly shaped grains. The grains comprise an agglomerate comprising at least one type of non-elastomeric thermoplastic. Alternatively the grains can be described as comprising an agglomerate comprising at least one type of non-elastomeric thermoplastic. At least a portion of the grains have fibrous extensions.
In some examples all or a majority of the grains have the fibrous extensions. In other examples at least 40% 50%, 60%, 70%, 80%, or 90% of the grains have the fibrous extensions. A fibrous extension as used herein encompasses a region of the grain that is substantially narrower than another portion of the grain. The material of the grain may be rigid, but the fibrous extension is narrow enough that the fibrous extension is able to flex or bend.
The use of the irregularly shaped grains as the artificial turf infill may have several benefits. One potential benefit is that the non-elastomeric thermoplastics can be used. Normally the artificial turf infill is made up of an elastomeric material or material which is easily pushed aside so that the artificial turf surface has lifelike properties such as mimicking the give of a real turf surface which has dirt or sand within it. The irregularly shaped grains have the benefit that there may be air pockets and the packing ratio of the artificial turf infill is reduced. This allows the hard non-elastomeric thermoplastics to be used and still have the properties which realistically mimic a real turf surface.
In another embodiment, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% of the irregularly shaped grains have a curved profile. Increasing the proportion of irregularly shaped grains with a curved profile may have the effect of increasing the amount of cavities or voids formed within the artificial turf infill. This may in turn provide for better shock absorption by the artificial turf infill.
In another embodiment, at least 40%, 50%, 60%, 70%, 80%, or 90% of the grains have the fibrous extensions. This embodiment may be beneficial because increasing the number or amount of fibrous extensions may provide for better shock absorption by the grains.
In another embodiment, in at least 50%, 70%, or 90% of the portion of the grains the fibrous extensions comprise at least 30% of the weight of the grains. This embodiment may be beneficial because increasing the number or amount of fibrous extensions may provide for better shock absorption by the grains.
In another embodiment, the at least one type of non-elastomeric thermoplastic is viscoelastic at temperatures below 100° C.
In another embodiment, the at least one type of non-elastomeric thermoplastic comprise recycled artificial turf fibers. Recycled artificial turf fibers are equivalent to artificial grass fibers. The recycled artificial turf fibers are artificial turf fibers which have been removed from a previously installed artificial turf surface. The use of the non-elastomeric thermoplastics from recycled artificial turf fibers may have the benefit that the reuse of the thermoplastic reduces the amount of waste which is deposited in landfills. It may also have the benefit that the recycled artificial turf fibers may have additives which would be useful for the artificial turf infill. For instance, the recycled artificial turf fibers may be colored green. Having the artificial turf infill a green color may be beneficial in making the artificial turf surface more lifelike looking. It may also have the benefit that the recycled artificial turf fibers have other additives such as UV protection which will increase the longevity of the artificial turf infill.
In another embodiment, the irregularly shaped grains have a longitudinally stretched out and curved volume expansion with ratios of length to diameter/cross sectioned within 1:2 to 1:50.
In another embodiment, the irregularly shaped grains have a longitudinally stretched out and curved volume expansion with ratios of length to diameter/cross-section within any one of the following: 1:4 to 1:50, 1:8 to 1:50, 1:16 to 1:50, and 1:32 to 1:50. This embodiment may be beneficial because as the irregualry shaped grains become narrower with respect to their length the irregularly shaped grains may become more flexible.
In another embodiment, the irregularly shaped grains have a sieve size between 0.2 mm and 12 mm. In this embodiment the irregularly shaped grains have been selected such that they pass through a first sieve with an opening of 12 mm or less. The irregularly shaped grains are further selected such that they are captured by a sieve with openings of 0.2 mm or greater. The opening of the first sieve remains greater than the opening of the second sieve.
In another embodiment the irregularly shaped grains have a sieve size below 12 mm. In this embodiment the irregularly shaped grains have been selected such that they pass through a sieve with an opening of 12 mm or less.
In another embodiment, the irregularly shaped grains have a thickness between 0.5 mm and 2 mm.
In another embodiment, the at least one type of non-elastomeric thermoplastic comprise any one of the following: at least one thermoplastic polymer, a polyolefin, waste plastic, fibrous waste plastic, pre-consumer yarn, post-consumer yarn recovered from synthetic sports fields, artificial turf fiber, recovered waste plastic, recycled packaging material, poly ethylene food packaging, poly ethylene, polypropylene, a poly ethylene and poly propylene mixture, LLDPE, HDPE, LDPE, MDPE, PP, PE, a polyolefin, and combinations thereof. This embodiment may be beneficial because thermoplastic which would normally be disposed of may be used for manufacturing a high quality artificial turf surface.
In another embodiment, the artificial turf surface further comprises a sand layer between the backing and the artificial turf infill. The use of the sand layer between the backing and the artificial turf infill may further serve to improve the replication of natural turf surface properties by the artificial turf surface. The use of the sand layer may also reduce the amount of artificial turf infill which is required to be used.
In another embodiment, the majority of the irregularly shaped grains have a curved profile. The curved profile may be in a cross-sectional view of the irregularly shaped grain. Having a curved profile may be beneficial because it may reduce how closely the irregularly shaped grains can be packed next to each other. Having them less dense may be beneficial because the artificial turf infill will have a more springy or elastic profile although the agglomerate is made of a non-elastomeric thermoplastic.
In another embodiment, the fibrous extensions of the irregularly shaped grains interlock with any one of the following: the artificial grass fibers, the fibrous extensions of other irregularly shaped grains, and combinations thereof. This embodiment may be beneficial because the interlocking of the fibrous extensions may serve to hold the irregularly shaped grains in the same position with respect to each other, and also possibly to help hold their position relative to the artificial grass fibers. This may for example have the benefit of reducing the splash effect when a ball hits an artificial turf surface. Splash is when the impact of a ball or other object causes artificial turf infill to fly up above the surface of the artificial turf surface. It resembles the splash of an object hitting a puddle of water.
In another embodiment, at least a portion of the fibrous extensions are branched. The branching of the fibrous extensions may be beneficial because it may make the fibrous extensions more flexible. The branching may also produce hook like structures that enable the irregularly shaped grains to better interlock either with themselves or artificial grass fibers.
In another embodiment, the artificial turf surface further comprises a top infill layer. The irregularly shaped grains are between the backing and the top infill layer.
In another embodiment, the top infill layer comprises regularly shaped granules. The regularly shaped granules may for example have round, oval, a rounded, or bead shaped appearance. The use of the regularly shaped granules may be beneficial because it may have the effect of reducing the friction between an object sliding on the artificial turf surface and the irregularly shaped grains.
In another embodiment, the regularly shaped granules comprises at least 50%, 70%, 90%, or 95% of the top infill layer by weight. This embodiment may be beneficial because as the amount of the regularly shaped granules increases in the top infill layer the friction between an object sliding on the artificial turf surface is further reduced.
In another embodiment, the top infill layer consists of the regularly shaped granules.
For example, the regularly shaped grains could be made from an agglomerate that is similar or has an equivalent composition to the irregularly shaped grains. In other examples the regularly shaped granules could be made from a elastomeric compound such as crumb rubber or other materials conventionally used as artificial turf infill. For example, the elastomeric granulates used for artificial turf infill could be placed on the surface artificial turf infill formed by the irregularly shaped grains. This may reduce the amount of elastomeric granulates that are used. As a smaller amount of the elastomeric granulate is used, it may reduce the splash effect when a ball or other object impacts the artificial turf surface.
In another embodiment, the regularly shaped granules comprise any one of the following: a least one thermoplastic polymer, a polyolefin, waste plastic, fibrous waste plastic, pre-consumer yarn, post-consumer yarn recovered synthetic sports fields, artificial turf fiber, recovered waste plastic, recycled packaging material, poly ethylene food packaging, EPDM, LLDPE, HDPE, LDPE, MDPE, PP, PE, a polyolefin, an elastomeric compound, rubber, crumb rubber, and combinations thereof.
In another embodiment, the top infill comprises elongated granules. In some examples, the elongated granules may comprise an elastic or flexible material. The use of the elongated granulates in the top infill may have several advantages. First, the elongated shape may help the top infill to remain above or covering the infill made from the irregularly shaped grains. The elongated shape may, in some examples, result in less friction between a person or object sliding on the artificial turf. The use of the elongated granules may also reduce the splash effect when a ball or other object impacts the artificial turf surface.
In another embodiment, the elongated granulate are formed from any one of the following: an elastomeric compound, shavings from a block of an elastomeric compound, rubber, crumb rubber, EPDM, and combinations thereof.
In another embodiment the elongated granulate are shavings formed from a block of an elastomeric compound. The use of the shavings from an elastomeric compound may make the artificial turf surface appear more realistic. The use of shavings from an elastomeric compound may also make the shaving have a fiber like structure that helps to keep them in place and reduce the splash effect.
In another embodiment, the top infill comprises at least 40%, 50%, 60%, 70%, 80%, 90%, or 95% of the elongated granules by weight. This embodiment may be beneficial because it may provide for an artificial turf surface that is less likely to damage or irritate the skin of a player when sliding on the playing surface. The reduction of the splash effect may also increase with a larger proportion of the elongated granules in the top infill.
In another embodiment, the top infill consists of the elongated granules. This embodiment may have the benefit of further reducing the splash effect.
In another embodiment, the artificial turf surface further comprises a sand layer between the backing and the artificial turf infill. The artificial turf surface further comprises a top infill layer, wherein the irregularly shaped grains are between the backing and the top infill layer. The top infill comprises irregularly shaped granulate. The irregularly shaped granulate comprises shavings from a block of an elastomeric compound. This embodiment may be beneficial because the irregularly shaped granulate may provide shock absorbency and also may reduce the friction between an object sliding on the artificial turf surface and the irregularly shaped grains.
In another aspect, the invention provides for a method of manufacturing an artificial turf system. An artificial turf system as used herein encompasses the components which are supplied to manufacture an artificial turf surface.
The method comprises providing an artificial turf carpet with a pile. The artificial turf carpet comprises a backing. The artificial turf carpet further comprises artificial grass fibers. The artificial grass fibers are tufted into the backing. The artificial grass fibers form the pile surface. The artificial grass fibers are secured to the backing.
The method further comprises agglomerating the at least one type of non-elastomeric plastic into an agglomerate for forming irregularly shaped grains to provide an infill for the artificial turf carpet.
In another embodiment, the agglomeration of the at least one type of non-elastomeric thermoplastic into the agglomerate and the forming of the irregularly shaped grains form the agglomerate is performed using an agglomerator. An agglomerator as used herein is a device which applies heat and pressure to agglomerate multiple thermoplastics into a single structure. The agglomerator may also cut or break the agglomeration into the irregularly shaped grains.
The use of an agglomerator may be beneficial because it may provide for an inexpensive means of manufacturing irregularly shaped grains.
In another embodiment, the agglomerator is a friction agglomerator. The friction agglomerator may have one or more moving portions which use friction to generate the heat necessary to form the agglomerate.
In another embodiment, the agglomerator is a disc agglomerator. The disc agglomerator may have one or more rotating discs which receive the heated non-elastomeric thermoplastic and agglomerate them into the agglomerate and form the irregularly shaped grains at the same time.
In another embodiment, the forming of the irregularly shaped grains from the agglomerate is performed using an extruder. The use of an extruder may be beneficial because the properties of the irregularly shaped grains may be precisely controlled. An extruder as used herein encompasses a device which heats the at least one type of non-elastomeric thermoplastic and then forces them through an orifice to extrude them. There may also be a device which cuts the extruded agglomerate into the irregularly shaped grains. The material extruded from the extruder may be referred to as an extrudate. However, the extrudate is the agglomerate.
In another embodiment, the extruder comprises any one of the following: an underwater pelletizing system, a water ring pelletizing system, a strand pelletizing system, and a hot-cut pelletizing system.
In another embodiment, the extruder optionally comprises a pelletizer or granulation system to additionally form the shape of the irregularly shaped trains.
In another embodiment, the forming of the irregularly shaped grains is performed using an extruder. The use of an extruder may be beneficial because it may allow for precise control of the properties of the irregularly shaped grains such as the length, the amount of curvature of the grain, and the relative size distribution.
In another embodiment, the extruder comprises an extrusion die plate. The extrusion die plate has at least one orifice for extruding the agglomerate. The at least one orifice has a first portion and an opposing portion. The first portion is rough. The opposing portion is smooth to form irregularly shaped grains that have a curved profile. The first portion, which is rough, causes a breaking or slowing effect as the agglomerate is extruded. This causes the resulting irregularly shaped grain to have a curved profile. This may be beneficial in that it may cause the irregularly shaped grains to pack less densely. This may cause them to have a more elastic behavior although they are made from a non-elastomeric thermoplastic.
In another embodiment, the extruder comprises multiple orifices. The multiple orifices have at least two distinct sizes. This embodiment may be beneficial because the size distribution of the irregularly shaped grains and their relative frequency can be precisely controlled.
In another embodiment, the multiple orifices may have an irregular shape or profile. The use of the irregular shape or profile may have the benefit of producing grains of agglomerate that are irregularly shaped.
In another embodiment, the extruder comprises a cutting system for cutting irregularly shaped grains.
In another embodiment, the cutting system of the extruder is configured for producing irregularly shaped grains with varying lengths. This may for instance be achieved by controlling how often the cutting system cuts off extrudate (the agglomerate) that is being extruded. By varying the times between when the agglomerate is cut or choosing a distribution of times the relative size distribution of the irregularly shaped grains can be controlled.
In another embodiment, the method further comprises mixing at least one additive into the agglomerate before forming the irregularly shaped grains. This may be beneficial in adding various properties to the irregularly shaped grains such as flame retardants, UV protection, or dyes to color to change the appearance of the artificial turf infill.
In another embodiment, the at least one additive comprises any one of the following: a colorant or dye, a UV stabilizer, a flame retardant, a filler, a blowing agent, an anti-seize agents, a lubricant, compatibilizer, a binding agent, and combinations thereof.
In another embodiment, the method further comprises recycling used artificial turf to provide the at least one of the at least one type of non-elastomeric thermoplastic. This may be beneficial in that it may reduce the environmental impact of installing a new artificial turf surface. It may also have the benefit that the thermoplastic recovered from the used artificial turf may have additives such as colorants or UV stabilizers or flame retardants that are already present. This may reduce the cost of manufacturing a new artificial turf surface.
In another embodiment the agglomerate at least comprises 80%, 90%, 95%, or 99% by weight the at least one type of non-elastomeric thermoplastic. In other words the agglomerate is at least 80%, 90%, 95%, or 99% (by weight) made from the at least one non-elastomeric thermoplastic. Increasing the amount of the non-elastomeric thermoplastic may have the benefit of increasing the mechanical stability of the fibrous extensions. If other materials such as sand or elastomeric materials are mixed into the agglomerate the irregularly shaped grains may be structurally compromised.
In another embodiment the agglomerate consists of the at least one type of non-elastomeric thermoplastic. This embodiment may be beneficial because the agglomerate is completely made from the at least one type of non-elastomeric thermoplastic. Although the agglomerate is made from the non-elastomeric thermoplastic it is flexible due to the fibrous extensions. The fibrous extensions are less likely to break apart when formed entirely from the at least one type of non-elastomeric thermoplastic.
In another embodiment the irregularly shaped grains consist of the agglomerate. This may provide for better structural integrity of the irregularly shaped grains.
In another aspect, the invention provides for a method of manufacturing an artificial turf surface. The method comprises a method of manufacturing an artificial turf system according to an embodiment. The method further comprises installing the artificial turf carpet. The method further comprises distributing the irregularly shaped grains within the pile and between the artificial grass fibers to form the artificial turf.
In another embodiment, the method of manufacturing the artificial turf surface comprises distributing a sand layer within the pile before distributing the irregularly shaped grains.
In another aspect, the invention provides for use of an agglomerate as infill for artificial turf. The agglomerate comprises irregularly shaped grains formed for at least one type of non-elastomeric thermoplastic. At least a portion of the grains may have fibrous extensions.
It is understood that one or more of the aforementioned embodiments of the invention may be combined as long as the combined embodiments are not mutually exclusive.
In the following embodiments of the invention are explained in greater detail, by way of example only, making reference to the drawings in which:
Like numbered elements in these figures are either equivalent elements or perform the same function. Elements which have been discussed previously will not necessarily be discussed in later figures if the function is equivalent.
Within the pile 104 and between the artificial grass fibers 108 is spread an artificial turf infill 114. In this case the infill 114 comprises irregularly shaped grains 116. The irregularly shaped grains are formed from an agglomerate comprising at least one type of non-elastomeric thermoplastic. The non-elastomeric thermoplastics may also be thermoplastic polymers. The use of the irregularly shaped grains causes voids 118 between a number of the irregularly shaped grains 116. These voids provide give and elasticity to the irregularly shaped grains 116 that are made of what is considered normally a rigid thermoplastic. This enables a material which would normally be unsuitable for making artificial turf infill function well. The artificial turf infill 114 may provide for helping the artificial grass fibers 108 to stay rigid and in the correct position. They may also provide for shock absorption or other physical properties which help the artificial turf surface 100 more approximate the properties of a real turf surface.
The irregularly shaped grains in
In the above table it can be see that the agglomerate infill made from the irregularly shaped grains has a shock absorbency that is comparable to the SBR infill made from recycled black crumb rubber. In fact, the larger grains (greater than 2.5 mm) surprisingly showed shock absorbency that was greater than the SBR infill material for all three impacts.
The following examples are several possible practical examples of artificial turf surfaces that use the irregularly shaped grains as artificial turf infill. Artificial turf infill made from irregularly shaped grains is referred to as “polymer agglomerate.” All weights refer to the amount of material distributed on the surface of an artificial turf carpet. The polymer agglomerate is placed on top of the sand layer. The term e-layer refers to a substructure made of a shock absorptive layer of rubber granulate, matting, or other material under the artificial turf carpet.
In the 5 above examples, the numerical values may be varied by up to 10%, 20, or 30% to produce alternative examples.
In examples 1 through 3, so size distribution of the polymer agglomerate is given. It is understood that any sieve size between 1 and 12.5 mm may be used to sort agglomerate for these two examples.
In examples 4 and 5: Grains that pass through the 2.5 mm sieve are used for example 4. The grains that are caught by the 2.5 mm sieve, but pass through a 12.5 mm sieve are used for example 5.
| Number | Date | Country | Kind |
|---|---|---|---|
| 16180026.3 | Jul 2016 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2017/068145 | 7/18/2017 | WO | 00 |
