EP3947818B1

EP3947818B1 - Artificial turf and method for producing it

Info

Publication number: EP3947818B1
Application number: EP20721122.8A
Authority: EP
Inventors: Marco Antonio RADICI
Original assignee: Radici Pietro Industries & Brands SpA
Current assignee: Radici Pietro Industries & Brands SpA
Priority date: 2019-04-04
Filing date: 2020-04-01
Publication date: 2023-07-12
Anticipated expiration: 2040-04-01
Also published as: EP3947818C0; EP3947818A1; IT201900005068A1; WO2020202234A1

Description

Technical field of the invention

The present invention relates to an artificial turf mat and a production process of an artificial turf mat.

State of the art

By artificial turf mat it is meant a mat comprising artificial strings that simulate the natural turf, usually used in the making of surfaces used for sports use (e.g. soccer fields, baseball fields, etc.) and/or for decorative use (e.g. gardens).
In the making of the aforesaid surfaces typically the artificial turf mats are laid on a rigid and compact substrate, for example in clay or concrete. Furthermore, typically a layer of, typically granular, material called infill (which can be made with various materials such as for example rubber granulate, also recycled, sand, vegetable material such as cork and/or coconut, etc.) is spread on the artificial turf mat between the artificial strings. The infill structurally stabilizes the artificial turf mat and/or it improves its aesthetic quality, making it looks more like to the natural turf (since it facilitates the upright maintenance of the artificial strings) and/or it facilitates its sports use, improving its performance properties (for example in terms of elastic response of the mat).
US2017/0152619 A1 describes an artificial turf mat comprising a dampening layer made of polymeric material, to which the artificial strings are fixed by tufting techniques. The dampening layer is arranged in vertically outermost and top position of the mat with respect to the other structural layers of the mat (in other words, the dampening layer is the first of the layers that make up the mat proceeding from top to bottom). The infill is arranged between the artificial strings of the mat directly in contact with the dampening layer and/or dispersed in the dampening layer. ITPI20090136A1 , US2003039773A1 and WO2008072073A2 disclose a respective artificial turf structure.

Summary of the invention

The Applicant has found that the known artificial turf mats have some drawbacks and/or can be improved in one or more aspects.
Firstly, according to the Applicant, the dampening layer of the known artificial turf mats, such as those described in US2017/0152619 A1 , given its vertically outermost and top position, is directly subjected to the interaction with the users and/or to the action of the atmospheric agents and/or to the solar radiation which can lead to mechanical and/or thermal and/or electromagnetic (e.g. UV) actions of the dampening layer. The mechanical actions can in turn cause, even significant and/or rapid, abrasion and/or wear of the dampening layer and/or of the artificial turf mat. Furthermore, the infills located in direct contact with the dampening layer or even interpenetrated in the dampening layer (as for example described in US2017/0152619 A1 ), can contribute, due to the nature of the materials used for the infills themselves (e.g. sand, coconut, etc.), to the aforesaid wear phenomena of the dampening layer, for example by increasing the abrasion.
The thermal actions can cause an excessive thermal rise of the dampening layer, especially when the artificial turf mat is used for outdoor surfaces and/or in the warmer seasons. These thermal and/or solar radiation actions, especially UV, can lead to a deterioration and/or degradation of the dampening layer and/or of the artificial turf mat (e.g. of one or more of the polymeric materials that make them up). According to the Applicant, one or more of the aforesaid actions (and in particular when present in synergy) can lead to the damaging of the dampening layer and/or of the artificial turf mat and/or to the possible decrease (up to the loss) of the performance properties of the latters (e.g. in terms of absorption and/or restitution of the actions undergone by the dampening layer) and/or to the possible annoyance and/or comfort decrease for the users.
This in turn may lead over time to a decrease/loss of ergonomics or safety of the mat for the users and/or the possible loss of the necessary regulatory requirements (e.g. FIFA standards) with consequent need for maintenance and/or replacement actions (and therefore related costs).
Object of the present invention is to provide an artificial turf mat that solves one or more of the aforesaid drawbacks.
Object of the present invention is to provide an artificial turf mat able to provide the appropriate performance properties (e.g. in terms of absorption and/or restitution of the actions undergone and/or of ergonomics for the user) and which is at the same time sturdy and/or compact and/or reliable and/or resistant (e.g. to the wear, to the high temperatures, to the atmospheric agents, etc.).
According to the Applicant the problem of achieving one or more of these objects is solved by an artificial turf mat and/or by a production process of an artificial turf mat according to the attached claims and/or having one or more of the following features. According to an aspect the invention relates to an artificial turf mat according to claim 1.
According to an aspect the invention relates to a production process of an artificial turf mat according to claim 11.
By dampening pad it is meant a layer of material (with cohesive structure, for example not granular, in order to be woven by the artificial strings) able of significantly improving the overall properties of the artificial turf mat as regards the absorption of the mechanical shock and/or the restitution of the energy and/or in terms of allowed maximum vertical (e.g. temporary and reversible) deformation, for example according to the FIFA qualification tests for the artificial turf pitches. According to the Applicant, the presence of the dampening pad allows to obtain an appropriate absorption and/or an appropriate restitution of the mechanical actions undergone by the artificial turf mat. In fact, the artificial turf surfaces, especially those used for sports use, have to meet multiple performance requirements, for example in terms of an appropriate balance between elasticity and rigidity of the obtained surface, to allow the practice of the sports activities (e.g. correct bounce of the ball) while keeping ergonomics and safety for the users (e.g. correct elasticity to limit annoyances and/or injuries to the users). In this way the appropriate performance properties (possibly in synergy with the infill) are given to the artificial turf surface. According to the Applicant, the support ply and the protective ply, arranged at opposite sides of the dampening pad (typically at respectively the upper face and the lower face when the artificial turf mat is installed in an artificial turf surface), create a protection for both the sides of the dampening pad, for example against atmospheric agents, abrasion, solar radiation, etc. In fact, the dampening pad is not in direct contact with the outside. Moreover, in use, the dampening pad is never (thanks to the aforesaid positioning of the support and protective plies) in direct contact with the infill, decreasing or eliminating the abrasion of the infill on the dampening pad. This allows to limit the damaging and/or the wear of the dampening pad and therefore a possible decrease and/or loss of the aforesaid performance properties.
According to the Applicant, one between the support ply and the protective ply (typically the protective ply with the mat arranged in an artificial turf surface) provides, thanks to its positioning at a face of the dampening pad, a protection for the dampening pad itself from the direct solar radiation. In this way, the aforesaid excessive temperature increase and the direct exposure to the UV rays of the dampening pad are limited and, consequently, the aforesaid phenomena dependent on them in terms of deterioration and/or degradation of the dampening pad and/or of the artificial turf mat, therefore limiting the damaging and the possible drop/loss of performance properties of the latters.
According to the Applicant, the artificial strings that pass through all three the support ply, the dampening pad and the protective ply allow to link together the aforesaid three elements with a single industrial phase of tufting. In this way, the sturdiness and/or the resistance and/or the compactness of the artificial turf mat are further improved, while keeping the process industrially simple and/or fast and/or cheap. The terms above, below, superiorly, inferiorly refer to a normal positioning of an artificial turf mat installed to make an artificial turf surface.
The present invention in one or more of the aforesaid aspects can have one or more of the following preferred features.
Preferably said dampening pad is made of polymeric material, more preferably of (solid) polymeric foam, even more preferably with closed cells. According to the Applicant these types of materials facilitates the making of the dampening pad having the desired performance properties.
Preferably making said composite layer comprises providing one among said support ply and said protective ply and (e.g. directly) applying on said one among said support ply and said protective ply a (e.g. liquid) mixture precursor of said dampening pad.
Preferably making said composite layer comprises laying another among said support ply and said protective ply on said dampening pad or on said mixture, at opposite side with respect to said one among said support ply and said protective ply.
Preferably making said composite layer comprises thermosetting said mixture to transform it into said dampening pad. The phase of thermosetting of the mixture can be performed before or after the aforesaid phase of laying of the another among the support ply and the protective ply on the dampening pad (if the thermosetting has already been performed) or on the mixture (and therefore formerly to the phase of thermosetting). According to the Applicant it is possible to make in both cases the composite layer having the desired performance properties (e.g. desired performance properties of the dampening pad and/or of the support and protective plies).
According to the Applicant the phases disclosed in the former three paragraphs allow the making of the composite layer in simple, fast and cheap manner.
Preferably making said composite layer comprises, more preferably before said applying on said one among said support ply and said protective ply said mixture, foaming said mixture. Preferably said foaming the mixture comprises adding to the mixture a foaming additive (such as for example a surfactant and/or a blowing agent). In this way the making of the dampening pad having the desired performance properties is facilitated.
Preferably said dampening pad has viscoelastic properties, more preferably it is made of viscoelastic material. Without limiting to any theory, by viscoelastic properties it is meant the ability of a material to withstand a given action (e.g. absorb the energy impressed by a shock) while keeping the ability to return, once the action has ceased, to its undeformed configuration owned before of the given action (e.g. absorb the action by deforming in non-permanent way) introducing an appropriate delay between the ceased of the action and the complete recovery of the undergone deformation. The viscoelastic materials, unlike the totally elastic materials, typically do not return the whole energy absorbed during a shock phenomenon, such as for example the fall of a user, the running, etc., but part of the absorbed energy is dissipated in viscous phenomena within the material itself. According to the Applicant, this feature facilitates the dampening effect of the pad (and therefore of the whole mat) since the user experiences a less abrupt and/or less intense impact in which part of the energy has been dissipated and, therefore, not returned.
Preferably said dampening pad is made of a material obtained by emulsion. Preferably said mixture is an emulsion.
Preferably said dampening pad is made of a polymeric material obtained by emulsion polymerization. Preferably said mixture is obtained by emulsion polymerization.
Preferably said dampening pad is made of a polymeric material obtained by solution polymerization. Preferably said mixture is obtained by solution polymerization.
Preferably said dampening pad is made of one or more of the following materials: styrene-butadiene rubber latex (SBR latex), styrene-butadiene latex (SBL), natural latex, polyurethane material (e.g. sorbothane), ethylene-propylene-diene-monomer rubber (EPDM), polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), polyamide (PA), even more preferably styrene-butadiene rubber latex. According to the Applicant, these materials provide the desired and appropriate performance properties, for example in terms of response to the shocks in viscoelastic deformation regime, etc. According to the Applicant, the presence of the protective ply according to the present invention allows the use of a dampening pad in latex, even when having limited mechanical and/or thermal and/or to the UV radiation resistance. Preferably making said composite layer, more preferably thermosetting said mixture, comprises cross-linking said mixture. In this way, it is produced the dampening mat having the desired performance properties, for example mechanical properties in terms of apportionment between elastic response and viscous response at a given action (e.g. relatively to the viscoelastic behaviour).
In one embodiment said mixture contains one or more cross-linking additives (e.g. sulphur or zinc oxide).
In this way it is facilitated the cross-linking of the mixture during the thermosetting phase for improving the (e.g. elastic and/or viscous) properties of the dampening mat to obtain the desired performance properties. According to the Applicant, it is possible, even by acting on the content of cross-linking additives, to vary the cross-linking degree of the completed dampening pad to obtain and/or regulate its performance properties (e.g. increasing the predominance of the elastic response over the viscous one at a given action and/or vice-versa) to optimize the pad to any different applicative needs.
Preferably a thickness of said dampening pad is greater than or equal to 1 mm, more preferably greater than or equal to 2 mm, even more preferably greater than or equal to 3 mm, and/or less than or equal to 17 mm, more preferably less than or equal to 15 mm, even more preferably less than or equal to 12 mm. According to the Applicant, this range of thicknesses allows to give the mat the desired performance properties while at the same time limiting the encumbrance of the mat and/or the use of material and therefore the related costs.
Preferably thermosetting said mixture comprises subjecting said mixture to a first temperature for a first time interval. Preferably said first temperature is greater than or equal to 100°C, more preferably greater than or equal to 120°C, and/or less than or equal to 190°C, more preferably less than or equal to 170°C. Preferably said first time interval is greater than or equal to 5 minutes, and/or less than or equal to 10 minutes.
In this way the thermosetting of the mixture is facilitated in order to properly make the dampening pad having the desired performance properties.
Preferably said protective ply has ability of absorption and/or retainment of liquid substances, typically of water. In this way, in use, the protective ply tends to remain wet. According to the Applicant the polymeric materials for example described in US2017/0152619 A1 for the making of the dampening layer (i.e. PVC, PE, PP, PA, EPDM) have a poor ability of absorption of the water, and therefore the pad remains basically dry. The aforesaid technical feature according to the present invention instead allows, with the protective ply wet, to further limit the aforesaid overheating (e.g. by radiation and/or conduction) of the dampening pad, thereby reducing the aforesaid phenomena of deterioration and/or of degradation and/or of damaging of the latter and/or of the artificial turf mat. Furthermore, in the making of the composite layer, it can be facilitated for example the application on the protective ply (for example by pouring) of the mixture precursor of the dampening pad, since the protective ply allows the penetration and the retainment of the mixture (typically water based).
According to the invention, said protective ply is made of non-woven fabric (preferably felt), more preferably obtained by needle-punching. Optionally (for increasing the resistance of the ply) finishing processes such as resin coating or heat setting can be carried out.
According to the invention, said protective ply is made of fibres of polymeric material (e.g. PP, PET, PE, etc.). In this way the ability of absorption and/or retainment of liquid substances of the protective ply is enhanced.
Preferably a thickness of said protective ply is greater than or equal to 0,5 mm, more preferably greater than or equal to 1 mm, and/or less than or equal to 6 mm, more preferably less than or equal to 5 mm. In this way the protective ply is sufficiently sturdy to protect the dampening pad from the aforesaid phenomena of damaging, while limiting the thickness of the protective ply and therefore the related cost and/or weight and/or not to degrade the performance properties provided by the dampening pad.
According to the invention, said protective ply is made of warp and weft fabric or knitted fabric, made by fibres of polymeric material (e.g. PP, PET, PA -e.g. Nylon-, etc.). Preferably a thickness of said protective ply, more preferably when made of warp and weft fabric, is greater than or equal to 0,1 mm, more preferably greater than or equal to 0,3 mm, and/or less than or equal to 5 mm, more preferably less than or equal to 3 mm. For this fabric these thicknesses are sufficient to make a protective ply sufficiently sturdy to protect the dampening pad.
Preferably said artificial strings have respective free end portions which protrude from said protective ply. Preferably said weaving by tufting said artificial yarn in said composite layer comprises making respective free end portions of said artificial strings which protrude from said protective ply. In this way, when the mat is correctly positioned in an artificial turf surface, the protective ply is arranged in vertically outermost position to protect the dampening pad. In this way, when the protective ply has also ability of absorption and/or retainment of liquid substances, the latter is suitably arranged to facilitate the absorption of the water (e.g. rain) possibly present on the artificial turf mat to keep it wet.
Preferably said artificial turf mat comprises a further dampening pad, more preferably arranged at (e.g. in contact with) said support ply, more preferably at opposite side with respect to said dampening pad. In this way the performance properties of the mat are further increased. In this way the use of infill can be further limited.
Preferably said further dampening pad has at least one of, more preferably all, the features of said dampening pad. In this way the production of the further dampening pad is facilitated (for example by using the same materials and/or precursor mixtures and/or machineries used for the production of the dampening pad).
Preferably said artificial strings are made of one or more of the following materials: polypropylene (PP), polyethylene (PE).
Preferably said artificial strings have one or more of the following structures: fibrillated structure, smooth monofilament structure, texturized monofilament structure. In this way the artificial turf mats have the desired mechanical properties (e.g. in terms of absorption of the actions) and/or the desired textures (e.g. to look as much as possible to a natural turf mat).
Preferably each of said artificial strings has a mass per unit of length greater than or equal to 400 dtex, more preferably greater than or equal to 1500 dtex, and/or less than or equal to 6000 dtex, more preferably less than or equal to 2500 dtex.
In case of artificial strings having fibrillated structure, each artificial string has a mass per unit of length greater than or equal to 2000 dtex, more preferably greater than or equal to 4000 dtex, and/or less than or equal to 10000 dtex, more preferably less than or equal at 8000 dtex.
Preferably a length of each respective free end portion of said artificial strings is greater than or equal to 10 mm and/or less than or equal to 65 mm. In this way the artificial turf mats have the desired mechanical properties and/or aesthetic features. Preferably said support ply and/or said protective ply is/are arranged in direct contact with said dampening pad. In this way the mat is rationally made, improving its sturdiness and/or compactness.
Preferably said support ply is made of warp and weft fabric. In this way the weaving by tufting of the artificial strings is facilitated.
In one alternative embodiment said support ply is made of non-woven fabric (e.g. felt, fiberglass, spun-bond, etc.) or knitted fabric.
Preferably said support ply is made of a material selected in the following group: polyethylene (PE), polypropylene (PP), polyamide (PA) (e.g. nylon), polyethylene terephthalate (PET).
Preferably a thickness of said support ply is greater than or equal to 0,1 mm, more preferably greater than or equal to 0,5 mm, and/or less than or equal to 2 mm, more preferably less than or equal to 1,5 mm. In this way the support ply is sufficiently sturdy while limiting the encumbrance and/or the weight of the latter.
Preferably said artificial turf mat comprises a fixing coating for fixing in position said artificial strings, more preferably (directly) applied on said support ply, even more preferably at opposite side with respect to said dampening pad. In this way the fixing coating blocks in position the curved portion of the artificial strings (typically formed in the tufting phase at the support ply) reducing the possibility of unthreading of the artificial strings themselves.
Preferably a thickness of said fixing coating is greater than or equal to 0,1 mm, more preferably greater than or equal to 0,3 mm, and/or less than or equal to 1,5 mm, more preferably less than or equal to 1 mm.
The fixing coating is in this way sturdy without exceeding in the consumption of material and therefore in the costs and/or in the overall weight of the mat.
Preferably said production process comprises, more preferably subsequently to said weaving by tufting, (e.g. directly) applying on said support ply, more preferably at opposite side of the support ply with respect to the dampening pad, a further (liquid) mixture precursor of a fixing coating. Preferably said production process comprises, subsequently to said applying said further mixture, thermosetting (e.g. cross-linking) said further mixture to transform it into said fixing coating. In this way the fixing coating, once hardened, facilitates the maintenance in position of the totality of artificial strings (e.g. incorporating the curved portion of each artificial string). Preferably said fixing coating is made of a material obtained by emulsion. Preferably said further mixture is an emulsion.
Preferably said fixing coating is made of a polymeric material obtained by emulsion polymerization. Preferably said further mixture is obtained by emulsion polymerization.
Preferably said fixing coating is made of a polymeric material obtained by solution polymerization. Preferably said further mixture is obtained by solution polymerization. Preferably said fixing coating is made of one or more of the following materials: styrene-butadiene rubber latex, styrene-butadiene latex, polyurethane material, polyvinyl chloride (PVC), polyethylene (PE), glue. According to the Applicant these materials can be arranged in fluid form (e.g. liquid, granular) on the support ply and incorporate, once thermoset (or anyway thermally treated), the curved portions of the artificial strings to fix the latters in position.
Preferably said thermosetting said further mixture comprises subjecting said further mixture to a second temperature for a second time interval. Preferably said second temperature is greater than or equal to 90°C, and/or less than or equal to 130°C. Preferably said second time interval is greater than or equal to 5 minutes, and/or less than or equal to 10 minutes.
In this way the thermosetting of the further mixture is obtained in an industrial way. According to an aspect the invention relates to an artificial turf surface comprising an artificial turf mat according to the present invention.
Preferably said artificial turf surface comprises a substrate, more preferably compact, on which said artificial turf mat lays. In this way a support for the whole surface is made.
Preferably said artificial turf surface comprises an infill layer arranged above said artificial turf mat (e.g. above the protective ply, between the artificial strings). In this way the performance and/or aesthetic properties of the artificial turf surface, in particular of the artificial turf mat, are furtherly improved for example in terms of mechanical strength and/or adhesion for the users and/or resemblance to the natural turf.
Preferably said infill layer has a mass per unit area greater than or equal to 4 kg/m², more preferably greater than or equal to 6 kg/m² and/or less than or equal to 40 kg/m², more preferably less than or equal to 30 kg/m². Thanks to the presence of the dampening pad the needed mass per unit area of the infill layer is significantly limited, with same performances provided to the artificial turf surface.
Preferably said infill layer is made of granules made of one or more (more preferably at least two) of the following materials: (siliceous) sand, polymeric material (such as SBR rubber, possibly recycled and ennobled by encapsulation with polyurethane material), natural material (e.g. coconut, cork, etc.). In this way the infill layer is suitably made.

Brief description of the drawings

Figure 1 schematically shows an artificial turf mat according to the present invention;
Figures 2a, 2b, 2c schematically show three subsequent steps of a production process of an artificial turf mat according to the present invention;
Figure 3 schematically shows an artificial turf surface according to the present invention.

Detailed description of some embodiments of the invention

The features and the advantages of the present invention will be further clarified in the following detailed description of some embodiments of the present invention, presented by way of non-limiting example, with reference to the attached figures.
In the figures with the number 1 is exemplarily indicated an artificial turf mat comprising a support ply 2, a protective ply 3 and a dampening pad 4 interposed between the support ply 2 and the protective ply 3. Exemplarily the support ply 2 and the protective ply 3 are arranged in direct contact with the dampening pad 4.
The artificial turf mat 1 comprises artificial strings 5 woven by tufting to the support ply 2, to the dampening pad 4 and to the protective ply 3 so that all the artificial strings 5 completely pass through the support ply 2, dampening pad 4 and protective ply 3.
Exemplarily the dampening pad 4 is made of closed cell solid polymeric foam of SBR rubber latex having viscoelastic properties. Exemplarily the SBR latex is obtained by emulsion polymerization.
Exemplarily a thickness S1 of the dampening pad 4 is equal to about 8 mm.
In one not shown embodiment the dampening pad can comprise a solid substrate and an open reticular structure, arranged directly above the solid substrate, made of a plurality of filaments fixed to each other to form a tangle having a three-dimensional development (as for example described in US2017/0152619 A1 ). In this embodiment the protective ply is arranged directly above the open reticular structure and the support ply is arranged below the solid substrate (in contact with the latter). Exemplarily the protective ply 3 is in felt made by needle-punching with fibres of polypropylene (PP) or polyester (PET) and it has a thickness S2 equal to about 2 mm.
In alternative, not shown, embodiments the protective ply can be made of warp and weft fabric or knitted fabric, with a thickness exemplarily equal to about 0,5 mm. Exemplarily the artificial turf mat 1 comprises artificial strings 5 all identical to each other and all having smooth monofilament structure and made of polypropylene (PP) or polyethylene (PE).
In the shown example each artificial string 5 comprises two free end portions 6 which protrude from the protective ply 3, two intermediate portions 7 (contiguous with the two end portions 6) which pass through the protective ply, the dampening pad and the support ply, and a curved portion 8 (contiguous with the two intermediate portions 7) protruding from the support ply 2 (figs. 1 and 3).
Exemplarily each end portion 6 of each artificial string 5 has a length L equal to about 50 mm.
In one not shown embodiment (which may not provide the use of infill), each end portion of each artificial string has a length equal to about 12 mm.
In one not shown embodiment (which may not provide the use of infill), the artificial strings comprise a first plurality of strings having a smooth monofilament structure and a second plurality of strings having a textured monofilament structure. The textured structure strings create a twisted structure that facilitates the dampening of the actions in combination with, or in place of, the infill layer. In this embodiment the twisted textured strings averagely remain more proximal to the protective ply and a length of the end portions of the smooth strings starting from the aforesaid twisted structure is about 12 mm.
Exemplarily each artificial string 5 has a mass per unit of length equal to about 2000 dtex.
Exemplarily the support ply 2 is of warp and weft fabric made of PP and it has a thickness S3 equal to about 1 mm.
Exemplarily the artificial turf mat 1 comprises a fixing coating 9 for fixing in position the artificial strings 5, directly applied on the support ply 2, at opposite side with respect to the dampening pad 4.
Exemplarily the fixing coating 9 is made of (not foamed) SBR rubber latex obtained by emulsion polymerisation. Exemplarily the fixing coating 9 has a thickness S4 equal to about 0,6 mm.
In figures 2a, 2b and 2c there are shown schematically, and purely by way of example, phases of a production process of an artificial turf mat according to the present invention.
Exemplarily the process comprises making a composite layer 99 comprising the support ply 2, a dampening pad 4 and a protective ply 3, wherein the dampening pad 4 is interposed between the support ply 2 and the protective ply 3.
With reference to figure 2a, exemplarily the process initially comprises providing the protective ply 3, for example carried out by a coil 80, and a liquid mixture 10 precursor of the dampening pad 4. The mixture 10 (e.g. LAITEX NF-5617 of LAIEX^™) is exemplarily obtained by emulsion polymerization and it is arranged in the tank 200 at the foaming and spreading station 100.
In some cases, the mixture may also contain an inert filling material (e.g. silica or calcium carbonate).
Exemplarily (fig. 2a) it is provided foaming the mixture 10, for example by adding a foaming additive (e.g. surfactant), at the foaming and spreading station 100.
After the foaming of the mixture 10, the process exemplarily comprises, at the foaming and spreading station 100, directly applying (e.g. pouring) onto the protective ply 3 the foamed liquid mixture 10, released from the tank 200. The ability of absorption and/or retainment of liquid substances of the protective ply 3 facilitates the application of the mixture 10, since the penetration and the retainment of the latter on the protective ply 3 is facilitated.
In one not shown embodiment, the liquid mixture 10 is directly poured onto the support ply 2 instead of onto the protective ply 3.
Subsequently the process exemplarily comprises thermosetting the mixture 10 to transform it into the dampening pad 4. Exemplarily thermosetting the mixture 10 comprises cross-linking the mixture. Exemplarily thermosetting the mixture 10 comprises maintaining a first set, consisting of the protective ply 3 (or of the support ply 2, in the alternative embodiment) and of the mixture 10 applied on it, in an oven 101 thermostated at a first temperature T1 equal to about 135°C for a first time interval equal to about 10 minutes. Subsequently (fig. 2b) the process exemplarily comprises laying the support ply 2 (or the protective ply 3, in the alternative embodiment) on the dampening pad 4, at opposite side of the dampening pad 4 with respect to the protective ply 3 (or to the support ply 2) for making the composite layer 99.
It is therefore provided weaving by tufting, at the tufting station 102 (for example comprising a tufting machine marketed by the Cobble^™), an artificial yarn 90 in the composite layer 99 to obtain artificial strings 5 which entirely pass through the composite layer 99.
Typically weaving by tufting the artificial yarn 90 in the composite layer 99 comprises making respective free end portions 6 of the artificial strings 5 which protrude from the protective ply 3, by the cut of the loops of yarn 90.
Subsequently (fig. 2c) the production process exemplarily comprises directly applying on the support ply 2, at opposite side of the support ply 2 with respect to the dampening pad 4, a further liquid mixture 20, precursor of a fixing coating 9. The further mixture 20 is exemplarily obtained by emulsion polymerization and it is applied onto the support ply by spreading through the application cylinder 500. Exemplarily the production process comprises, subsequently to applying the further mixture 20, cross-linking the further mixture 20 to transform it into the fixing coating 9, for example by subjecting a second set, consisting of the protective ply 3, dampening pad 4, support ply 2, artificial strings 5 and the further mixture 20, to a second temperature T2, equal to about 120°C, for a second time interval equal to about 7 minutes. The second set is subjected to the second temperature T2 thanks to the oven 101, in which the second set is inserted again. In this step of the process, the oven 101 is suitably thermostated to be able to heat the second set according to a desired temperature distribution. Exemplarily a first portion 101a of the oven 101, facing the further mixture 20 (e.g. the upper one), is thermostated at the second temperature T2, while a second portion 101b of the oven 101, i.e. the one facing the artificial strings 5 (e.g. the lower one), is instead thermostated at a third temperature T3 of about 50°C. Exemplarily the second set is preheated in a pre-oven 103 before being inserted into the oven 101.
In use, the artificial turf mat 1 is typically installed to make an artificial turf surface 400 such as that shown in figure 3.
Exemplarily the artificial turf surface 400 comprises a compact clay substrate 401 (for example as known), on which the artificial turf mat 1 is laid.
Exemplarily the artificial turf surface 400 comprises an infill layer 402 arranged above the artificial turf mat 1, in particular above the protective ply 3, between the free end portions 6 of the artificial strings 5.
Exemplarily the infill layer 402 is made of granular polymeric material (such as SBR rubber granules, recycled and ennobled by encapsulation with polyurethane material) and it has a mass per unit area equal to about 10 kg/m².
In one not shown embodiment the infill layer can be made by a stabilizing first sub-layer (e.g. of silica sand) above which a performance second sub-layer is arranged (e.g. of ennobled granular polymeric material).
Exemplarily, in case of horizontal drainage, the artificial turf surface comprises a draining layer 403 (typically composed of a ply of waterproof material and of a draining system, not shown) arranged directly above the substrate 401 and below the artificial turf mat 1. Alternatively, the artificial turf surface can have a vertical drainage (wherein the water leaks into the ground).

Claims

Artificial turf mat (1) comprising:
- a support ply (2);

- a dampening pad (4);

- a protective ply (3),
wherein said dampening pad (4) is interposed between said support ply (2) and said protective ply (3);

- artificial strings (5) woven by tufting to said support ply (2), dampening pad (4) and protective ply (3) so that all said artificial strings (5) pass entirely through said support ply (2), dampening pad (4) and protective ply (3),
characterized in that said protective ply (3) is made of fibres of polymeric material and in that said protective ply (3) is made of non-woven fabric or warp and weft fabric or knitted fabric.
Mat (1) according to claim 1, wherein said dampening pad (4) is made of polymeric material, and wherein said dampening pad (4) has viscoelastic properties.
Mat (1) according to claim 1 or 2, wherein said dampening pad (4) is made of solid polymeric foam with closed cells.
Mat (1) according to any one of the previous claims, wherein said dampening pad (4) is made of one or more of the following materials: styrene-butadiene rubber latex, styrene-butadiene latex, natural latex, polyurethane material, ethylene-propylene-diene-monomer rubber, polyvinyl chloride, polyethylene, polypropylene, polyamide.
Mat (1) according to any one of the previous claims, wherein a thickness (S1) of said dampening pad (4) is greater than or equal to 1 mm and less than or equal to 17 mm.
Mat (1) according to any one of the previous claims, wherein said protective ply (3) has ability of absorption and/or retainment of liquid substances, wherein said protective ply (3) is made of felt, and wherein a thickness (S2) of said protective ply (3) is greater than or equal to 0.5 mm and less than or equal to 6 mm.
Mat (1) according to any one of the previous claims, wherein said support ply (2) is made of warp and weft fabric, wherein said support ply (2) is made of a material selected in the following group: polyethylene, polypropylene, polyamide, polyethylene terephthalate and wherein a thickness (S3) of said support ply (2) is greater than or equal to 0.1 mm and less than or equal to 2 mm.
Mat (1) according to any one of the previous claims, wherein said support ply (2) and/or said protective ply (3) is/are arranged in direct contact with said dampening pad (4).
Mat (1) according to any one of the previous claims, wherein said artificial strings (5) have respective free end portions (6) which protrude from said protective ply (3), wherein a length (L) of each respective free end portion (6) of said artificial strings (5) is greater than or equal to 10 mm and less than or equal to 65 mm.
Mat (1) according to any one of the previous claims, wherein said artificial turf mat (1) comprises a fixing coating (9) for fixing in position said artificial strings (5), applied on said support ply (2), at opposite side with respect to said dampening pad (4), wherein a thickness (S4) of said fixing coating (9) is greater than or equal to 0.1 mm and less than or equal to 1 mm, and wherein said fixing coating (9) is made of one or more of the following materials: styrene-butadiene rubber latex, styrene-butadiene latex, polyurethane material, polyvinyl chloride, polyethylene, glue.
Production process of an artificial turf mat (1), the process comprising:
- making a composite layer (99) comprising a support ply (2), a dampening pad (4) and a protective ply (3), wherein said dampening pad (4) is interposed between said support ply (2) and said protective ply (3);

- weaving by tufting an artificial yarn (90) in said composite layer (99) to obtain artificial strings (5) which pass entirely through said composite layer (99), characterized in that said protective ply (3) is made of fibres of polymeric material and in that said protective ply (3) is made of non-woven fabric or warp and weft fabric or knitted fabric.
Production process according to claim 11, wherein said protective ply is made of non-woven fabric, preferably felt, obtained by needle-punching, wherein making said composite layer (99) comprises providing one among said support ply (2) and said protective ply (3) and applying on said one among said support ply (2) and said protective ply (3) a mixture (10) precursor of said dampening pad (4), wherein making said composite layer (99) comprises laying another among said support ply (2) and said protective ply (3) on said dampening pad (4) or on said mixture (10), at opposite side with respect to said one among said support ply and said protective ply and wherein making said composite layer (99) comprises thermosetting said mixture (10) to transform it into said dampening pad (4).
Production process according to claim 12, wherein making said composite layer (99) comprises, before applying on said one among said support ply (2) and said protective ply (3) said mixture (10), foaming said mixture (10), wherein said foaming the mixture (10) comprises adding to the mixture (10) a foaming additive, wherein thermosetting said mixture (10) comprises cross-linking said mixture (10), and wherein said mixture (10) is obtained by emulsion polymerization or by solution polymerization.
Production process according to any one of claims from 11 to 13, wherein said weaving by tufting said artificial yarn (90) in said composite layer (99) comprises making respective free end portions (6) of said artificial strings (5) which protrude from said protective ply (3), wherein said production process comprises, subsequently to said weaving by tufting, applying on said support ply (2), at opposite side of the support ply (2) with respect to the dampening pad (4), a further mixture (20) precursor of a fixing coating (9), wherein said production process comprises, subsequently to said applying said further mixture (20), thermosetting said further mixture (20) to transform it into said fixing coating (9).
Artificial turf surface (400) comprising an artificial turf mat (1) according to any one of claims from 1 to 10, wherein said artificial turf surface (400) comprises an infill layer (402) arranged above said artificial turf mat (1) and wherein said infill layer (402) has a mass per unit area greater than or equal to 4 kg/m² and less than or equal to 40 kg/m².