US20240003080A1

US20240003080A1 - Carpet in synthetic grass and method of making of said carpet in synthetic grass

Info

Publication number: US20240003080A1
Application number: US18/252,043
Authority: US
Inventors: Maurizio Gilardi; Nikolaos Sarris
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-11-10
Filing date: 2021-11-08
Publication date: 2024-01-04
Also published as: WO2022101761A1; EP4244421A1

Abstract

A carpet in synthetic grass of an entirely synthetic or hybrid type including a support extending mainly along a plane and defining an upper face and a lower face opposite the upper face, a plurality of synthetic grass threads constraint to the support to define fixing portions protruding from the lower face, glue spread on the fixing portions, a geotextile membrane in non-woven fabric arranged in correspondence with the lower face to cover the support on that side and in contact with the glue on the fixing portions, in which the geotextile membrane is included in the carpet in percentages between 0.5% and 3.5% with respect to the total weight of the carpet.

Description

The present invention relates to a carpet in synthetic grass and method of making said carpet in synthetic grass of the type specified in the preamble of the first claim. In particular, the present invention relates to a fully synthetic or hybrid type of recyclable carpet in synthetic grass and the related making method which allows the carpet to be produced.
As is known, carpets in synthetic grass are composed of synthetic fibres, usually green in colour and which simulate natural grass, and a horizontal support, called backing, which supports these synthetic fibres.
The conventional methods of making such carpets can be manifold.
A first method, for example, mainly comprises two phases: the tufting phase and the fixing phase of the synthetic fibres to the backing.
Tufting consists in the stitching of synthetic fibres, in a horizontal line or zig zag, to a mesh backing that can be closed or open.
The nets, usually in polypropylene, with closed mesh are intended for the production of entirely synthetic carpets, while the open mesh nets are intended for the production of hybrid carpets in which it is possible to grow, in addition, natural grass. Regardless of the type of carpet, the fixing of the tufts of synthetic fibres involves the spreading of a fluid glue (coating) consisting of thermosetting polymeric material, for example latex or polyurethane, or thermoplastic, such as polyethylene and polypropylene, to block the tufts of the synthetic fibres in the lower part under the primary backing. The fluid glue is applied over the entire surface of the backing in order to make it waterproof.
Following passage in the oven to stabilize the glue, holes are applied to the backing. These holes can have diameters between 5-6 mm and allow the vertical flow of water through them.
The known technique described comprises some important drawbacks.
Considering the distribution of the holes in the available space of the backing, the water flow is usually equal to 0.17% of the surface and, therefore, excessively reduced. In the event of severe thunderstorms, the possibility of play is impaired because the water takes more hours to drain. The excess water above the synthetic carpet is transported by horizontal flow, following the slope of the field, transporting the granular infill material especially if the infill is light and floats in the water such as cork, rice husk, corn cob and more.
The method described above, of course, is not recommended for the manufacture of carpets intended for hybrid grass systems as the latter involve root penetration to the underlying plant substrate and require much higher porosity. Not even the application of numerous holes allows the roots to penetrate the backing due to the surface tension of the water which prevents gas exchange if deposited on a perforated but flat surface.
A second fixing method is constituted by finger coating.
The latter consists in the spreading of thermosetting fluid to the backing arranged in rows, in correspondence with the lower part of the tufts of the synthetic fibres by means of a grid or rake that limits the application of the fluid glue exclusively above the rows of the sewn tufts, thus leaving the space between the rows without fluid glue.
However, taking into account the high quantity of fluid glue necessary to fix the tufts of the fibres and the reduced distance between the rows of tufts, the glue also flows laterally, beyond the rows of synthetic tufts, and occupies a large part of the space between the rows of the tufts.
This lateral outflow leaves only a few millimetres of the backing without spreading, less than 30% of the totality of the surface, partially improving the draining capacity of the backing, in the part without spreading. However, the main drawback is given by the fact that the remaining part is waterproofed by the fluid glue and, in the case of closed backing, the 30% of draining backing is certainly better than the method previously described, but in some cases insufficient as, for example, for example, in case it is necessary to allow the outflow of water during severe summer storms. The spreading method with thermosetting fluid glue is also applied to carpets manufactured for hybrid grass systems with the application of glue, to a very small extent, on the entire surface (light coating) or partially on the seam line of the synthetic tufts (finger coating) as previously described, to avoid obstructing the holes in the net from which the roots must then pass, but with a poor result as regards the fixing of the tufts of the synthetic fibres to the backing.
A further drawback of light coating or finger coating systems applied on hybrid carpets is given by the fact that the coating of thermosetting material on the backing makes the latter rigid and this rigidity makes the whole system harder and, therefore, with very low shock absorption. and often not in line with market and regulatory standards.
A third method of fixing the fibres is given by thermo-bounding.
It consists in the heat setting of the synthetic fibres to the primary backing, immediately after sewing, by means of a heated calender with the aid of a second backing in non-woven geotextile. This second backing is heated to high temperatures in such a way as to block the synthetic fibres creating a “sandwich” structure and preventing the synthetic fibres and any glue from coming into contact with the calender.
The calender then heats the fibres and any glue, causing a partial fusion, so the synthetic fibres adhere to each other through the glue which consists of grains or crushed fibres of thermoplastic material, such as polyethylene and polypropylene. Any thermoplastic grains, in fact, partially melt and contribute to the thermo-fixing by adherence of the grains to the synthetic fibres, to the primary backing, where the tufts of the synthetic fibres have been sewn, and to the secondary backing also necessary to be able to heat the fibres and any grains trapped between the two supports.
The method favours the drainage of water over the entire surface as the water penetrates through the porosity of both backings and between the spaces of the grains which, while melting, leave numerous cavities for water drainage. However, even this method has some drawbacks.
The partial fusion necessary to make the tufts of the synthetic fibres weld with a strength greater than 30/35 N, makes them weaker and, therefore, they break more easily at the base, or rather near the melting point.
Furthermore, the synthetic fibres are curled by the application of excessive heat, similar to the point of their fusion, losing their aesthetic properties and, finally, the synthetic carpet made with heat sealing shows the synthetic fibres excessively crushed.
This last drawback has the effect of increasing the difficulties inherent in the subsequent “combing”, during the laying of the granular infill, which is necessary to allow the infill material to penetrate and lift the fibres that must necessarily protrude on the surface.
Furthermore, once the part subjected to heat setting has cooled down, the carpets thus produced cause at least part of the backings to undergo localized shrinkage which substantially entails the creation of a wrinkled carpet support surface. Wrinkling can therefore involve problems during the drafting and use of the carpets themselves.
In addition, the known heat-setting methods provide for the use of multiple backings and materials and most of the materials involved in making the carpet are not recyclable. Therefore, once used, the carpet cannot in any way be redeveloped or recycled for other uses.
In this situation, the technical task underlying the present invention is to devise a carpet in synthetic grass and a method of making said carpet capable of substantially obviating at least part of the aforementioned drawbacks.
Within the scope of said technical task, an important object of the invention is to obtain a carpet in synthetic grass, whether it is entirely synthetic or hybrid, which is substantially recyclable for other uses.
Furthermore, a further object of the invention is to provide a carpet that does not have wrinkles along the supporting surface.
A further aim of the invention is to obtain a method of making a carpet in synthetic grass which makes the latter suitable both for the production of exclusively synthetic carpets and for the production of hybrid carpets.
Another important object of the invention is to devise a method that allows to obtain a carpet in synthetic grass capable of providing correct drainage for the surface defined by the backing and the fibres even in the presence of extreme climatic situations such as summer storms.
A further object is also to provide a carpet that comprises a distribution of synthetic grass in good condition and capable of allowing the subsequent processing to which a carpet according to the invention is usually subjected.
In conclusion, a further object is to provide a method of making a synthetic turf carpet that is economical and extremely performing in terms of surface drainage.
The technical task and the specified aims are achieved by a carpet in synthetic grass and method of making said carpet as claimed in the annexed claim 1.
Preferred technical solutions are highlighted in the dependent claims.

The characteristics and advantages of the invention are clarified below by the detailed description of preferred embodiments of the invention, with reference to the accompanying drawings, in which:

- the FIG. 1 shows a diagram of a carpet in synthetic grass according to the invention;
- the FIG. 2 illustrates the passage of a carpet between the pressure means and the heating surface of an apparatus for the realization of a method of making a carpet in synthetic grass in accordance with the invention in which it is evident that the pressing means and heating go into direct contact with the substrate; And
- the FIG. 2 is a diagram of operation of an apparatus for the realization of a method of making a carpet in synthetic grass according to the invention. In the present document, the measurements, values, shapes and geometric references (such as perpendicularity and parallelism), when associated with words like “about” or other similar terms such as “approximately” or “substantially”, are to be considered as except for measurement errors or inaccuracies due to production and/or manufacturing errors, and, above all, except for a slight divergence from the value, measurements, shape, or geometric reference with which it is associated. For instance, these terms, if associated with a value, preferably indicate a divergence of not more than 10% of the value.

Moreover, when used, terms such as “first”, “second”, “higher”, “lower”, “main” and “secondary” do not necessarily identify an order, a priority of relationship or a relative position, but can simply be used to clearly distinguish between their different components.
Unless otherwise specified, as results in the following discussions, terms such as “treatment”, “computing”, “determination”, “calculation”, or similar, refer to the action and/or processes of a computer or similar electronic calculation device that manipulates and/or transforms data represented as physical, such as electronic quantities of registers of a computer system and/or memories in, other data similarly represented as physical quantities within computer systems, registers or other storage, transmission or information displaying devices.
The measurements and data reported in this text are to be considered, unless otherwise indicated, as performed in the International Standard Atmosphere ICAO (ISO 2533:1975).
With reference to the Figures, the carpet in synthetic grass according to the invention is globally indicated with the number 1.
The carpet 1 can be used for the flooring of an exclusively synthetic grass pitch or a hybrid grass pitch, that is, made up of synthetic grass and natural grass.
The carpet 1, moreover, preferably comprises at least one support 2 and some threads 3.
The support 2 is substantially preferably a geometric element in which two dimensions are of orders of magnitude greater than the third. An example of this type is given by a plate or a membrane. Substantially, therefore, the support extends mainly along a plane.
Therefore, the support 2 defines an upper face 2 a and a lower face 2 b.
The upper and lower faces 2 a, 2 b are opposite to each other and, conventionally, since the support 2 is included in a carpet 1 for flooring, the lower face 2 b is the face suitable for being attached to the ground, while the upper face 2 a is the face exposed and covered with the infill in place.
The support 2 preferably comprises, in particular, a net 20. Said net 20 is, for example, a fabric or a membrane consisting of a plurality of holes suitable for allowing the passage of objects inside it. The meshes of the net 20 can be more or less extended according to the use of the carpet 1.
Preferably the mesh 20 is a conventional mesh of the type used for the common backing of carpet in synthetic grasses and comprises narrow meshes if the carpet 1 is used for purely synthetic grass pitches and extended for hybrid grass pitches. In a preferred but not exclusive embodiment, the net 20 is made up of a fabric. The fabric is preferably made of non-biodegradable polymeric material and more preferably of polyester or alternatively polypropylene or preferably high-density polyethylene.
It is also preferably made from a plurality of overlapping and mutually woven weaves, each having a base weft which is periodically repeated along substantially the entire fabric. Furthermore, each weave has a base weft of different dimensions compared to the other weaves along the expansion plane of the fabric itself. In particular, it consists of three, and alternatively more than three or even only two, intertwining each with a base, that is a portion of minimum dimensions that is repeated periodically along substantially the entire fabric, of different dimensions, in particular width in the plane of the fabric. This solution follows that the weaves with base wefts of larger dimensions periodically overlap the weaves with base wefts of smaller dimensions, creating a three-dimensional and jagged surface as previously described.
The fabric can also have openings having average dimensions of the main orthogonal diameters, between 2 mm and 0.5 mm, more preferably between 1.5 mm and 0.5 mm. In particular, the openings can have different average dimensions of the main orthogonal diameters and the smaller diameter can have a length between mm and 0.4 mm, so as to prevent the passage of sand and, at the same time, allow the passage of the roots.
The weight of the fabric is preferably between 20 g/m²and 350 g/m²and more preferably between 250 g/m²and 350 g/m².
Said fabric can also be primed with vinyl or acrylic glue.
Preferably the fabric is a warp knitted fabric made with warp-knit looms, or rather a Raschel-type machine.
The filaments that make up the fabric, preferably in polyester, can have a mass between 600 dtex and 800 dtex.
The threads 3 are preferably synthetic grass threads of a known type. The threads 3 are preferably constrained to the support 2 in such a way as to define fixing portions 30, protruding from the lower face 2 b of the support 2.
Therefore, they mainly protrude towards the upper face 2 a so as to simulate natural grass blades.
Preferably the threads 3 are sewn onto the support 2 in such a way as to be U-shaped around portions of the support 2. In this case, the central portion of the threads 2 protrudes from the lower face 2 b of the support 2 defining the aforementioned fixing portions 30. In detail, the threads 3 are preferably collected in tufts whose ends are inserted inside two adjacent links in such a way as to trap one side of a mesh between the two ends of the tuft. The free ends of the wires 3 therefore protrude from the upper face 2 a like grass, while the central part of them is arranged in a U shape on the lower face 2 b.
Preferably, the fixing portion 30 of each wire 3 protrudes from the lower face 2 b by a maximum of 5-6 mm.
The support 2, both for fields with exclusively synthetic or hybrid grass, preferably also comprises a geotextile membrane 4.
The geotextile membrane 4 is preferably made of non-woven fabric.
Preferably, but not necessarily, the membrane 4 has a weight of between 20 g/m²and 300 g/m²and more preferably between 100 g/m²and 220 g/m², and/or preferably a density between 1 g/cm³and 3 g/cm³preferably between 1.2 g/cm³and 1.5 g/cm³.
The geotextile membrane 4 is a known type membrane and can be arranged in correspondence with the lower face 2 b of the support 2 in such a way as to cover the support 2 on that side.
Preferably, the geotextile membrane 4 includes polymeric material, for example polyester.
In general, preferably, the carpet 1 also includes a glue 5.
The glue 5 is preferably spread on the fixing portions 30 of the threads 3. In particular, preferably, the glue 5 is arranged in correspondence with the side of the lower face 2 b of the support 2.
In this way, preferably, if the carpet 1 also includes the geotextile membrane 4, the glue 5 defines a layer between the support 2 and the geotextile membrane 4, even more in detail, between the fixing portions 30 and the membrane 4.
Therefore, the membrane 4 is preferably arranged in correspondence with the lower face 2 b in contact with the glue 5 on the fixing portions 30.
The glue 5 is preferably thermoplastic polymeric material. However, other materials could be used equivalently.
In a preferred embodiment, the carpet 1 comprises a support 2, or backing, consisting of polypropylene, threads 3 consisting of polyethylene, a glue 5 consisting of polyethylene and a geotextile membrane 4 consisting of polyester.
In general, among all the components of the carpet 1, typically the geotextile membrane 4 alone is not recyclable or difficult to recycle.
Advantageously, the making method as described below allows a carpet 1 to be made in which, with respect to the total weight of the carpet 1, the geotextile membrane 4 is in percentages of between 0.5% and 3.5%. Even more in detail, the geotextile membrane 4 is included in the carpet 1 in percentages between 1% and 3% of the total weight. More conveniently, the geotextile membrane 4 is included in the carpet 1 in percentages by weight of approximately 2%.
This low incidence of the geotextile membrane 4 on the carpet 1 implies that the carpet 1, unlike common carpets, is entirely recyclable.
The making method which allows the aforesaid fabric 1 to be made is preferably made by means of an apparatus 10.
This apparatus 10 is at least able to press the belt 1 from opposite directions along the faces 2 a, 2 b of the support 2.
This action can be undertaken by a plurality of different apparatuses such as presses or rollers or the like.
The apparatus 10 can therefore comprise a plurality of elements in series suitable to allow the realization of the method 1.
The apparatus 10 preferably defines a sliding trajectory 1 a.
The sliding trajectory 1 a is substantially defined by the trajectory assumed by the carpet 1 along the construction line of the apparatus 10.
More in detail, preferably, the sliding trajectory 1 a is defined by the movement line of the support 2. Therefore, the apparatus 10 can comprise direction means 11, adapted to direct the carpet 1 in such a way as to define the sliding trajectory 1 a. Said direction means 11 can be tracks on which the support 2 slides in a controlled manner, or rollers adapted to convey the carpet 1 along predetermined directions. Preferably, the direction means 11 comprise one or more rollers. The latter are, in particular, adapted to receive the support 2 comprising the wires 3, for example directly from an external apparatus.
This external apparatus, not included in the apparatus 10, can be a power supply apparatus 20.
By feeding apparatus 20 we simply mean an apparatus suitable for feeding the apparatus 10 with at least the support 2 on which the threads 3 are constrained. For example, the feeding apparatus 20 can include a sewing device suitable for sewing, first of the threads 3 arriving at the apparatus 10 on the support 2 so as to prepare them for subsequent processing.
Furthermore, the power supply apparatus 20 can include tensioning means, even just simple rollers, suitable for tensioning the support 2 provided to the apparatus 10. Alternatively, or together with the tensioning means, the direction means 11 can also tension themselves the support 2 including the threads 3.
Among the external apparatuses, not included in the apparatus 10, there is also a reception apparatus 30.
The reception apparatus 30 is simply adapted to receive the carpet 1 at the end of the workings carried out by the apparatus 10. Therefore, like the feeding apparatus also the reception apparatus 30 can include tensioning means for maintaining the carpet 1 in tension.
Furthermore, the apparatus 10 can include direction means 11 close to the reception means 30 in such a way as to replace or cooperate with the tensioning means possibly present in the reception apparatus 30.
In conclusion, preferably, between the external apparatuses, known in the current state of the art, suitable for collaborating with the apparatus 10 there is also a conveying apparatus 40.
The conveying apparatus 40 is preferably adapted to convey the geotextile membrane 4 onto the support 2 in such a way as to combine the support 2 and the membrane 4.
In particular, preferably, the conveying apparatus 40 is adapted to convey the geotextile membrane along the sliding direction 1 a of the support 2. Such apparatuses are, in any case, extremely well known to those skilled in the art. Likewise, the way in which the apparatus 10 and the external apparatuses 20, 30, cooperate is extremely well known to the skilled in the art.
The apparatus 10 preferably comprises at least gluing means 12 and heating means 13.
The gluing means 12 are suitable for spreading glue 5 on the support 2, in particular on the fixing portion 30 above the net 20.
They preferably comprise a container 120 and deposition means 121. The container 120 is a casing suitable for containing and storing glue 5. Preferably, the glue 5 is arranged inside the casing 120 in solid granular form. The latter, as already mentioned, can be polyethylene, but also polypropylene. The container 120 can be fixed or even interchangeable on the apparatus 10.
Preferably, the container 120 is able to interface with the deposition means 121 and to release at least part of its contents onto the said deposition means 121.
The deposition means 121 are, in fact, preferably suitable for depositing glue 5 on the carpet 1. In detail, they are preferably suitable for depositing thermoplastic material in liquid form, preferably exclusively on the fixing portions 30 defined by the threads 3 intertwined or sewn on the support 2.
Preferably the deposition means 121 deposit glue 5 only on the intermediate parts of the wires 3 without coming into contact with the mesh 20, or rather with the lower face 2 b of the underlying support 2.
More in detail, the deposition means 121 preferably take the glue 5 in solid granular form from the container 120 and heat it to melt it.
Obviously, the melting temperature varies according to the thermoplastic material in use.
For example, in the case of polypropylene, the melting temperatures can be around 130° C. In general, the deposition means 121 preferably bring the thermoplastic glue to temperatures between 70° C. and 160° C.
Preferably, the deposition means 121 comprise a roller operatively connected to the container 120. The container 120 releases, for example by gravity, glue 5 onto the surface of the roller which, placed at the appropriate temperature as indicated above, melts the glue and deposits it on the carpet. 1.
The roller is preferably placed not in direct contact with the lower face 2 b of the support 2, but in contact exclusively with the fixing portions 30, protruding from the lower face 2 b.
However, the arrangement means 121 could comprise a heated plate arranged on the sliding line 1 a or other devices which ensure a controlled deposition of the glue.
Preferably, the arrangement means 121 are spaced at least 1 mm from the lower surface 2 b of the support 2 which slides along the sliding path 1 a. More conveniently, the sliding means 121 are arranged at a distance even less than 10 mm, more preferably still between 3 mm and 7 mm, in a preferred example they are arranged at about 5 mm from the support 2 so as not to touch the lower face 2 b of the support 2 itself.
Specifically, this last sentence means that the glue application surfaces 5, such as the lateral surface of the rollers or the base area of a heated plate, are spaced from the support 2 which slides along the sliding path 1 a according to the distances indicated.
Obviously, the distance is medium from the surface and there may be irregular elements of the support 3 which exceed, by tolerance, the said distances. Advantageously, the sliding means 121 can also be oscillating at least along a predetermined direction. In detail, preferably, the sliding means 121 oscillate perpendicularly to the sliding trajectory 1 a or parallel to the sliding direction 1 a.
In this, the glue 5 is distributed on the support 2, in detail on the fixing portions 30, by brushing the same. In other words, the sliding means 121 thus created define a brush effect which increases the effectiveness of the glue 5 on the fixing portions 30.
The heating means 13, preferably, are arranged along the sliding trajectory 1 a. In particular, preferably, the heating means 13 define a heating surface 13 a. The latter is suitable for heating the carpet 1 to temperatures equal to at least 100° C. More conveniently, the heating means 13 heat the carpet 1 to temperatures preferably between 120° C. and 180° C., equal to about 160° C. Preferably, this temperature is maintained for a time interval ranging from 1 to 15 s.
Preferably the heating surface 13 a is adapted to come into contact exclusively with the fixing portions 30 and/or with the geotextile membrane 4 of the support 2. It is configured not to adhere directly to the lower face 2 b.
As for the direction means 11, also the heating means 13 can be of variable shapes and sizes.
Preferably the heating means 13 comprise a roller heated to the indicated temperatures and the heating surface 13 a corresponds to the lateral surface of the roller.
Alternatively, the heating means 13 can comprise a plate on which the carpet 1 passes according to the configurations described above.
The pressing means 14 are also preferably arranged along the sliding trajectory 1 a and are able to press the carpet 1 starting from the free ends of the threads 3, or from the upper face 2 a of the support 2.
Preferably, the pressing means 14 they work in contrast to the heating surface 13 a. In particular, the pressure means 14 press the upper face 2 a.
Preferably, the pressure means 14 are also adapted to pressurize the carpet 1 in such a way as to put only the fixing portions 30 of the threads 3 under direct pressure and not the remaining surface of the lower face 2 b of the support.
This occurs because preferably the pressure means 14 do not allow the lower face 2 b to come into contact with the heating surface 13 a.
In the preferred embodiment, the pressure means 14 are configured to prevent the heating surface 13 a from coming into contact with the lower surface 2 b during the passage in correspondence with the pressure means 14.
Furthermore, even more in detail, the means for pressure 14 are configured in such a way as to prevent the geotextile membrane 4 from coming into contact with the lower surface 2 b by exerting a direct pressure on the latter.
In order to achieve this configuration, it is sufficient, for example, that the distance between the heating surface and the pressure means 14 is greater than the thicknesses defined by the support 2, fixing portions 30 and geotextile membrane 4.
Preferably, the pressure means 14 are further spaced by a length equal to at least part of the threads 3 protruding from the upper surface, as shown in FIG. 2 , in such a way that the fixing portions 30 are squeezed towards the support 2 without the pressure means 14 reaching even the upper surface of the support 2.
For this purpose, preferably, the pressure means 14 comprise a roller. This roller is preferably not heated, but cooled, and is arranged at a suitable distance, as previously described, from the heating means 13. Preferably, in particular, the pressure means 14 are arranged at least 2 mm from the heating means 13.
Also, in this case the pressure means 14 could be of a different type.
They could comprise a plate, or they could be controllable devices such as jacks or pistons or comprise elastic elements, for example springs, to exert the desired pressure on the carpet 1.
The heating means 13 and pressure 14 also serve to make the membrane adhere geotextile 4 to the remaining part of the carpet 1.
In other words, preferably, the pressure 14 and heating means 13 are configured not to come into contact with the support 2 of the carpet 1 while they each perform their own function.
The apparatus 10 further comprises cooling means 15.
The cooling means 15 are substantially similar to the heating means 13. Therefore, they are preferably arranged along the sliding trajectory 1 a.
In particular, preferably, the cooling means 15 define a cooling surface 15 a.
The latter is suitable for cooling the carpet 1 to temperatures equal to a maximum of 10° C. More conveniently, the cooling means 15 cool the carpet 1 to temperatures preferably between 2° C. and 8° C., equal to about 5° C. Preferably, this temperature is maintained for a time interval ranging from 1 to 15 s.
Preferably the cooling surface 15 a is adapted to come into contact exclusively with the fixing portions 30 and/or with the geotextile membrane 4 of the support 2. It is configured not to adhere directly to the lower face 2 b.
Like the heating means 13, the cooling means 15 can also be of variable shapes and sizes.
Preferably, the cooling means 15 comprise a water-cooled roller at the indicated temperatures and the cooling surface 15 a corresponds to the lateral surface of the roller.
Alternatively, the cooling means 15 can comprise a plate on which the carpet 1 passes according to the configurations described above.
The cooling means 15, in particular, by cooling in the indicated manner prevent the support 2 from wrinkling, considerably improving the yield of the carpet 1.
The operation of the apparatus 10 previously described in structural terms is as follows.
The apparatus 10 is connected, for example, to various external apparatuses including a power supply apparatus 20, from which it receives a support 2 on which wires 3 are suitably constrained, a conveying apparatus 40, from which it receives the geotextile membrane 4 from lay on the fixing portions 30 from the side facing the lower surface 2 b of the support 2, and a reception apparatus 30 adapted to substantially receive the carpet 1 once the workings by the apparatus 10 have been completed. Substantially, therefore, the power supply apparatus 20 is preferably upstream of the apparatus 10, the reception apparatus 30 is downstream of the apparatus 10. The conveying apparatus 40 is, on the other hand, configured to convey the geotextile membrane 4 onto the support 2 following the past of the support 2 and of the wires 3 in correspondence of the gluing means 12 and before the heating means 13. Therefore, the glue 5 is usually arranged between the fixing portions 30 and the geotextile membrane 4.
The direction means 11 place the support 2 under tension and define a sliding trajectory 1 a along which the support 2 and, at the end of the processing, the actual carpet 1 slides.
The deposition means 12 meanwhile take glue 5 in solid granular form from the container 120 and deposit it along the fixing portions 30.
Once the glue 5, now in liquid form, has been spread on the fixing portions 30 arranged on the side of the support 2 comprising the lower surface 2 b, the support 2 receives the geotextile membrane from the part corresponding to the lower surface 2 b in such a way that the geotextile membrane 4 rests on the glue 5 arranged on the fixing portions 30.
Furthermore, the support assembly 2, threads 3 and membrane 4, passes in correspondence with the heating means 13 which preferably heat the geotextile membrane 4, the glue 5 and the fixing portions 30 through the heating surface 13 a. The heating occurs substantially by conduction along the geotextile membrane 4 in such a way as not to put the lower face 2 b of the support 2 under direct pressure. This is possible thanks to or rather to the fact that the heating surface does not touch the lower face 2 b.
Finally, the pressure means 14 exert on the fixing portions 30, through the geotextile membrane 4, a pressure towards the support 2 without the heating surface 13 a acting in opposition to the pressure means 14 coming into contact with the lower face 2 a of the support 2.
The pressure means 14 then presses the upper face 2 a in such a way that the lower face 2 b does not touch the heating surface 13 a or in such a way that the geotextile membrane 4 is pushed against the fixing portions 30, but not directly against the lower face 2 b of the support 2.
The method of making a carpet 1 in synthetic grass is, as mentioned, preferably made by the apparatus 10, and comprises at least a step for constraining the threads 3 to the support 2, a spreading phase and a pressing phase.
The constraining phase of the threads 3 on the support 2 can be undertaken by means of machines or apparatuses of a known type for sewing. It consists in the arrangement of the threads 3, for example grouped in tufts, around support portions 2 and, in particular, of mesh 20.
In the spreading phase, the glue 5 is spread exclusively on the fixing portions 30. This spreading can take place, as described, by means of oscillating deposition means 121 to improve the effectiveness of the spreading.
This step is preferably carried out when the components of the carpet 1 pass through part of the deposition means 11.
In the pressing phase the apparatus 10 preferably presses exclusively the fixing portions 30 towards the support 2 without placing the lower face 2 b of the support 2.
This last phase preferably takes place when support 2, wires 3 pass between the heating means 13 and the pressure means 14 according to the configurations described above.
The method also includes other phases: a heating phase and a joining phase.
In the heating phase, the carpet 1 is heated and this phase takes place after the spreading phase. Preferably it is heated to temperatures above 100° C.
Furthermore, the heating phase is preferably immediately preceding the pressing phase.
The joining phase preferably takes place exclusively if the support 3 also comprises the geotextile membrane 4. In the preferred embodiment, the method also includes the joining phase.
Preferably in the joining phase the geotextile membrane 4 is arranged in correspondence with the lower face 2 b of the support 2 in such a way as to cover it entirely, but without coming into contact with it.
In fact, the junction points are preferably constituted by the fixing portions 30, on which the glue 5 is distributed from the spreading phase, on which the geotextile membrane 4 is substantially rested.
Preferably the joining phase is performed between the spreading step and the heating step. Furthermore, preferably, the actual junction of the textile membrane 4 with the fixing portions 30 takes place during the heating and pressing phase.
In conclusion, before the carpet 1 is conveyed to a reception apparatus 30, the method provides for a cooling phase. As already mentioned, the cooling phase has the purpose of avoiding the onset of wrinkling on the surface of the support 2.
In particular, the cooling phase is preferably carried out after the pressing phase. Basically, in the cooling phase the carpet 1 is cooled to maximum temperatures equal to 10° C.
The carpet in synthetic grass 1 and relative method for making said synthetic grass carpet according to the invention achieve important advantages.
In fact, the carpet 1 is entirely recyclable while guaranteeing excellent performance in use. In fact, the method as described allows to reduce above all the geotextile membrane content so as to make the carpet 1 sufficiently resistant, but at the same time recyclable, as already mentioned.
In particular, the fact of avoiding wrinkling by cooling, allows to reduce the thickness of the membrane with the consequent possibility of reducing the weight contribution thereof and to create entirely recyclable carpets 1.
Furthermore, the method allows to realize without any difference or substantial modification carpets 1 for fields with exclusively synthetic grass or hybrid grass, or rather mixed with natural grass.
This advantage is achieved without any modification in the main manufacturing phases of the carpet.
Furthermore, the method makes it possible to make a carpet 1 in synthetic grass capable of offering greater drainage than carpets of the known art.
The fact of not placing the lower face 2 b of the support 2 under direct pressure and of compressing the fixing portions 30 within predetermined limits, for example, by the distances of the rollers of the apparatus 10 with respect to the support 2, as previously described, avoids deposition of the glue 5 in the lower face portion of the support 2 comprised between the fixing portions 30 or around them.
In this way, the permeability of the mesh 20 that makes up the support 2, or possibly of the mesh 20 and of the geotextile membrane 4, is entirely preserved, but the correct junction between the wires 3 and the support 2 is guaranteed as the glue 5 can punctually percolate in the fibers.
In addition to what has been said, a further advantage of the method according to the invention is given by the fact that the reduced pressures to which the entire carpet 1 is subjected allow to wear or bend in a limited way the fibers protruding from the upper face 2 a of the support. 2. Therefore, the method allows to make carpets with greater resistance and easy installation.
The invention is susceptible of variants falling within the scope of the inventive concept defined by the claims.
In particular, before the spreading phase, a pre-heating phase could be envisaged. In the pre-heating phase, the pre-heating means 16 could heat the support 2 and the threads 3 in such a way as to further facilitate the spreading. In this case, the apparatus 10 could also comprise the pre-heating means 16.
These pre-heating means 16 could substantially be made with an IR lamp positioned in such a way as to heat the lower surface 2 b of the support 2 passing in correspondence with of the pre-heating means 16 along the sliding trajectory 1 a.
In this context, all the details can be replaced by equivalent elements and the materials, shapes and dimensions can be any.

Claims

1. A carpet in synthetic grass of an entirely synthetic or hybrid type comprising:

a support extending mainly along a plane and defining an upper face and a lower face opposite to said upper face,

a plurality of threads of synthetic grass constraint to said support to define fixing portions protruding from said lower face,

glue spread on said portions of fastening,

a geotextile membrane in non-woven fabric arranged at said lower face to cover said support on that side and in contact with said glue on said fixing portions,

wherein said geotextile membrane is comprised in said carpet in percentages between 0.5% and 3.5% with respect to the total weight of said carpet.

2. A method of making a carpet in synthetic grass by means of an apparatus,

said carpet comprising at least

glue spread on said fixing portions,

a geotextile membrane in non-woven fabric arranged in correspondence with said lower face to cover said support in that side and in contact with said glue said fixing portions,

and said method comprising:

constraining said wires on said support to define said fixing portions,

spreading said glue exclusively on said fixing portions,

splicing, after said spreading, said geotextile membrane with said glue on said fixing portions to couple said membrane with said support along said face,

heating said carpet to temperatures equal to at least 100° C. after said spreading step,

pressing exclusively said fixing portions towards said support without coming into contact with at least said lower face,

and

cooling said carpet to maximum temperatures equal to 10° C. after said pressing.

3. The method according to claim 2, wherein in said phase of constraint of said threads are sewn on said support such that said threads are arranged in a U around said portions of support, the central portion of said threads protruding from said lower face of said support defining said fixing portions.

4. The method according to claim 3, wherein said apparatus comprises gluing means configured to realize said step of spreading and wherein said glue is a thermoplastic polymer and is deposited on said support in liquid form.

5. The method according to claim 4, wherein said gluing means comprise at least one container including said glue in solid granular form and deposition means configured to withdraw said thermoplastic glue in the form solid granular from said container and to heat it bringing it to fusion.

6. The method according to claim 5, wherein said deposition means are constituted by a roller placed not in direct contact with said lower face of said support, but in contact with said fixing portions protruding from said lower face, said deposition means being also oscillating at least along a predetermined direction to realize a brush effect on said fixing portions.

7. A The method according to claim 5, wherein said apparatus comprises direction means adapted to define a sliding trajectory for said carpet along which said support slides in said apparatus and wherein said deposition means are spaced from said sliding trajectory by at least 1 mm.

8. A The method according to claim 2, wherein said apparatus comprises heating means arranged along said sliding trajectory and defining a heating means capable of heating said carpet to realize said heating phase, and wherein in said pressing phase a pressure is exerted in opposition to said heating surface.

9. The method according to claim 8, wherein said apparatus comprises pressure means arranged along said sliding trajectory pressing said fixing portions towards said support in contrast to said heating surface and configured such that none of said pressure means and said heating surface comes into contact with said support.

10. A The method according to claim 2, wherein said apparatus comprises cooling means arranged along said sliding trajectory and defining a heating surface capable of cooling said belt to realize said cooling phase, and in which said cooling means are water-cooled to a maximum temperature equal to 5° C.

11. The method according to claim 6, wherein said apparatus comprises direction means adapted to define a sliding trajectory for said carpet along which said support slides in said apparatus and wherein said deposition means are spaced from said sliding trajectory by at least 1 mm.

12. The method according to claim 11, wherein said apparatus comprises heating means arranged along said sliding trajectory and defining a heating means capable of heating said carpet to realize said heating phase, and wherein in said pressing phase a pressure is exerted in opposition to said heating surface.

13. The method according to claim 12, wherein said apparatus comprises pressure means arranged along said sliding trajectory pressing said fixing portions towards said support in contrast to said heating surface and configured such that none of said pressure means and said heating surface comes into contact with said support.