ARTIFICIAL TURF AND METHOD OF MANUFACTURING

Abstract

A method of manufacturing an artificial turf provides for moving a carrier mesh through an air gap formed between a first electrode and a second electrode of a dielectric barrier discharge device, applying a dielectric barrier discharge to a backside of the carrier mesh for plasma-activating the backside, and applying a backing layer to the plasma-activated backside of the carrier mesh for providing the artificial turf.

Claims

1-23. (canceled)

24. A method of manufacturing an artificial turf, comprising: moving a carrier mesh through an air gap formed between a first electrode and a second electrode of a dielectric barrier discharge device, wherein the carrier mesh includes a backside, and wherein the carrier mesh includes fibers integrated such that a portion of the fibers are exposed on the backside; applying a dielectric barrier discharge to the backside of the carrier mesh for plasma-activating the backside; and applying a backing layer to the plasma-activated backside of the carrier mesh for providing the artificial turf.

25. The method of claim 24, wherein the first and second electrodes are elongated in a first direction, and wherein the carrier mesh is moved in a second direction that is perpendicular to the first direction.

26. The method of claim 24, wherein the carrier mesh includes a frontside, wherein the first electrode is adjacent to the backside, wherein the second electrode is adjacent to the frontside, and wherein the second electrode is at least partially encased in a dielectric, the dielectric extending at least in a direction towards the first electrode.

27. The method of claim 24, wherein the second electrode is a metal cylinder which is at least partially encased in a dielectric.

28. The method of claim 24, wherein the dielectric comprises a plastic material.

29. The method of claim 24, wherein the dielectric has a thickness of at least 0.2 cm.

30. The method of claim 24, wherein the dielectric is shaped as a hollow cylinder with circular or ellipsoid cross section, wherein the second electrode is elongated along a major axis of the dielectric, and wherein the dielectric is in contact with the frontside of the carrier mesh.

31. The method of claim 24, wherein the second electrode is at least partially encased in the dielectric and is configured to be rotatable about its longitudinal axis.

32. The method of claim 31, wherein rotating the second electrode with the dielectric moves the carrier mesh through the air gap formed between the first electrode and the second electrode.

33. The method of claim 24, wherein the moving of the carrier mesh through the air gap comprises moving the carrier mesh through the air gap at at least one of a manually-adjustable and automatically-adjustable speed.

34. The method of claim 24, wherein the applying the dielectric barrier discharge comprises applying the dielectric barrier discharge at an energy density of at least 0.1 J/cm.sup.2.

35. The method of claim 24, further comprising manually or automatically adjusting a gap between the first electrode and second electrode.

36. The method of claim 35, wherein the gap is adjusted such that a distance between the first electrode and the outer surface of the dielectric at least partially enchasing the second electrode is greater than 0 mm.

37. The method of claim 24, wherein the first electrodes are positioned such that a distance between the first electrode and a surface of the backside of the carrier mesh and the fiber portions protruding therefrom is below 10 mm.

38. The method of claim 24, wherein the applying of the dielectric barrier discharge further comprises controlling the dielectric barrier discharge device to continuously apply the dielectric barrier discharge for plasma-activating the backside.

39. The method of claim 24, wherein the first electrode is a single wire or a set of two or more wires.

40. The method of claim 24, wherein the first electrode is a conductive profile or a set of two or more of said profiles.

41. The method of claim 24, wherein the first electrode is a set of two or more conductive wires or profiles galvanically decoupled from each other.

42. The method of claim 24, wherein the method is part of a continuously executed, inline roll-to-roll production process comprising: unrolling a carrier mesh roll; tufting the fibers into the unrolled carrier mesh; performing the method according to claim 24 for providing the artificial turf; and forming an artificial turf roll from the provided artificial turf.

43. An artificial turf, comprising: a carrier mesh including a backside, wherein the carrier mesh includes fibers integrated such that a portion of the fibers are exposed on the backside; and a backing layer positioned on the backside of the carrier mesh and connected to the backside via a plasma-discharge-assisted homogeneous distribution of binding forces between a backside surface of the carrier mesh and the backing layer.

44. The artificial turf of claim 43, wherein the homogeneous distribution of binding forces between the backside of the carrier mesh and the backing layer is the result of a homogenous distribution of ions forming covalent bonds between the backside of the carrier mesh and the backing layer.

45. The artificial turf of any one of claim 43, wherein a tuft binding force is determined by pre-processing the artificial turf according to DIN EN 13744 and then determining the tuft withdrawal force according to FIFA Test Method 26, whereby the tuft binding force is at least 40 N.

46. A method of manufacturing an artificial turf, comprising: moving a carrier through an air gap formed between a first electrode and a second electrode of a dielectric barrier discharge device; applying a dielectric barrier discharge to one side of the carrier for plasma-activating the side; and using the plasma-activated carrier for manufacturing the artificial turf.

Description

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

[0073] The following embodiments of the invention are explained in greater detail, by way of example only, making reference to the drawings in which:

[0074] FIG. 1 shows a production line system for manufacturing an artificial turf, according to an embodiment of the present invention;

[0075] FIG. 2 illustrates a portion of the carrier mesh of FIG. 1 after exiting the fiber inserter of FIG. 1, according to an embodiment of the invention;

[0076] FIG. 3 illustrates a portion of the carrier mesh of FIG. 1 after exiting the dispensing unit of FIG. 1, according to an embodiment of the invention;

[0077] FIG. 4 shows a y-z cross section of the DBD device of FIG. 1, and the control unit 114 of FIG. 1, according to an embodiment of the invention;

[0078] FIG. 5 shows a z-x cross-sectional view of the DBD device of FIG. 1, according to an embodiment of the invention;

[0079] FIG. 6 shows an overhead perspective view of the DBD device of FIG. 1, according to an embodiment of the invention which uses two wires as first electrodes;

[0080] FIG. 7 illustrates a method for method of manufacturing an artificial turf, according to an embodiment of the invention;

[0081] FIG. 8 is an illustration of the plasma activation process using a metal bar; and

[0082] FIGS. 9A and 9B show experimental data obtained for samples of artificial turf.

DETAILED DESCRIPTION OF THE INVENTION

[0083] The descriptions of the various embodiments of the present invention have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

[0084] FIG. 1 shows a production line system 100 for manufacturing an artificial turf, according to an embodiment of the present invention. The system includes a fiber inserter 102 configured to receive an artificial turf carrier mesh 104 and artificial turf fiber 106, and insert the artificial turf fiber 106 into the carrier mesh 104, by, for example, weaving or tufting the fiber into the carrier mesh 104. In some embodiments, the fibers include polyethylene or polypropylene and the carrier mesh comprises polypropylene. In other embodiments, the carrier mesh is or comprises a mixture of different polymer fibers, e.g., polypropylene fibers, polyethylene fibers and/or polyamide fibers.

[0085] The carrier mesh is also referred to as primary backing. The production line system 100 includes a conveyor assembly 107, including conventional rollers 108, as well other conventional components used in conveyor assemblies, such as drive systems (not shown) for driving one or more of the rollers 108, transport platforms (not shown), etc., configured in combination to move the carrier mesh to (and or through) each processing station, such as through the fiber inserter processing station 102.

[0086] FIG. 2 illustrates a portion of the carrier mesh 104 at location 110 in the system 100 after exiting the fiber inserter 102, according to an embodiment of the invention. In the embodiment illustrated, the carrier mesh 104 includes fibers 106 that have been tufted into the carrier mesh 104. It can be seen that a small loop of tuft fiber 202 extends (i.e., is exposed) on a backside 204 of the carrier mesh 104. Each series of the most closely spaced exposed tuft fibers 202 form a tuft row 210. The distance between two tuft rows can be, for example, 0.2 cm to 2.0 cm, e.g. about 0.25 cm, 0.5 cm or 1.0 cm. The tufted fibers 106 form a pile surface 206 on a front side 208 of the carrier mesh 104.

[0087] Referring again to FIG. 1, the system 100 includes a dielectric barrier discharge (DBD) device 112 and a control unit 114. As will be discussed in further detail below in conjunction with FIG. 4, the control unit 114 is configured to control the DBD device 112 to apply a dielectric barrier (i.e., plasma) discharge to the backside 204 of the carrier mesh 104 as the carrier mesh 104 moves through the DBD device 112 for plasma-activating the backside 204 in preparation for applying a backing layer, also referred to in the art as a secondary backing or secondary backing layer, by a dispensing unit 116.

[0088] As noted, the dispensing unit 116 applies a backing layer to the plasma-activated backside 204 of the carrier mesh 104. FIG. 3 illustrates a portion of the carrier mesh at location 119 of the system 100, after exiting the dispensing unit 116, according to an embodiment of the invention. FIG. 3 is identical to FIG. 2, with the additional feature of a backing layer coating 302 (e.g., a polyurethane or a colloidal latex backing layer coating) that has been applied to the plasma-activated backside 204 by the dispensing unit 116. The backing layer coating 302, also referred to as a backing layer 302, covers tufted regions (i.e., those regions containing the loops 202), well as the other remaining non-tufted regions of the plasma-activated backside 204 of the carrier mesh 104.

[0089] Referring again to FIG. 1, the dispensing unit 116 is configured to coat the plasma-activated backside 204 of the carrier mesh 104 with a polyurethane or latex 118. In one embodiment, the latex 118 is a colloidal latex, however, the polyurethane may be applied as a liquid or a foam. In the exemplary embodiment illustrated, the dispensing unit 116 is a lick roll including a rotating element 122 used to apply the polyurethane or colloidal latex 118 to the plasma-activated backside 204 of the carrier mesh 104. However, the scope of the invention includes other means of applying the coating 302. For example, and in another exemplary embodiment, the dispensing unit 116 is configured as a knife-over-roll dispensing unit (not shown) for first applying the polyurethane or the colloidal latex onto the plasma-activated backside 204 and then leveling the applied material using the conventional knife-over-roll process. When a knife-over-roll technique is used, the greige good typically has a different orientation, such that the side from which the fibers protrude faces downwards, allowing to apply the liquid backing by pouring or spraying it onto the opposite, upwards-facing side.

[0090] The system 110 may optionally include an anti-blistering applicator 122, configured in one embodiment as a spray bar. However, the scope of the invention covers any apparatus/process of applying a preferably small amount of anti-blistering agent 124 to the polyurethane or colloidal latex coating (i.e., to the backing layer coating 302) on the backside 204 of the carrier mesh 104. As illustrated, the applicator 122 is configured to wet a region 126 of the backing layer 302 with the anti-blistering agent 124.

[0091] Th system optionally includes a heater 128. The heater has an entrance 130 and an exit 132. The applicator 122 may be configured such that the wet region 126 is a distance 134 from the entrance 130 of the heater 128. The system 100 is configured to control the distance 134, via moving the heater 128 or the applicator 122, to control the time period between application of the anti-blistering agent 122 to any region of the carrier mesh 104 and entry of this region into the heater 128 via entrance 130. Time periods may vary depending upon ambient environmental conditions, such as ambient temperatures, relative humidity, etc. In one embodiment, the heater 128 and/or the applicator 122 are configured to be moveably-adjustable along the path of motion of the carrier mesh 104 on the conveyor assembly 107 for adjusting, either manually by an operator or automatically by the system (e.g., by the control unit 114, based upon operator input and/or sensor data), the distance 134.

[0092] The heater 128 is configured to remove water from the backing layer coating 302, thereby curing it for forming a solid backing layer 136. In one embodiment, when the artificial turf carrier mesh 104 exits the heater 128, the manufacturing of the artificial turf by the system 100 is complete, although in additional optional embodiments, the artificial turf fibers 106 may be trimmed after leaving the heater 128. Furthermore, in other embodiments, the backing layer coating 302 may cure before reaching the heater 128 and/or applicator 122, as a result of conditions of the ambient environment, which may be controlled by an operator, and/or length of time after being applied by the dispensing unit 116, and thus the manufacturing of the artificial turf by the system 100 is considered complete before reaching the heater 128 or the applicator 122. In one embodiment, the artificial turf mesh 104 with the integrated fibers 106 and the backing layer 302 exiting the dispensing unit 116 is the manufactured artificial turf of the present invention. In other embodiments, the artificial turf mesh 104 with the integrated fibers 106 and the backing layer 302 exiting the applicator 122 or the heater 128 is the manufactured artificial turf of the present invention.

[0093] The heater 128 may function in different ways. In the illustrated exemplary embodiment, the heater 128 has a first heat control element 138 and a second heat control element 140. The first heat control element 138 generates forced air 142 with a first temperature range and the second heat control element 140 generates forced air 144 with a second temperature range. In this way, the temperature of the backside 204 can be controlled to be different from that of the frontside 206 during the curing process. This may lead to effective removal of water from the backing layer coating 302 while protecting the artificial turf fibers 106 against high temperatures.

[0094] The manufacturing process and the system for manufacturing an artificial turf depicted in FIG. 1 comprises a fiber inserter 102. However, according to other embodiments (not shown), the artificial turf is manufacture in a roll-to-roll process and the system is free of a fiber inserter 102 or the fiber inserter is not used. For example, the manufacturing process described with reference to FIG. 1 may start with unrolling a roll of greige good (a carrier mesh comprising the already integrated fibers, but being free of a backing layer) and the unrolled greige good is fed into the air gap of the dielectric barrier discharge device. Then, the backside of the greige good (opposite to the side from which the fibers protrude) is plasma-activated using a dielectric barrier discharge technique, the liquid backing is applied onto the plasma-activated backside, optionally dried in an oven, and then rolled up to provide a roll of artificial turf.

[0095] FIG. 4 shows a y-z cross section of the DBD device 112 of FIG. 1, and the control unit 114, according to an embodiment of the invention. The DBD device 112 includes a first electrode 402 and a second electrode 404, and is illustrated with the carrier mesh 104 partially occupying an air gap g 405 formed between the first and second electrodes 402, 404, as discussed further below. The first and second electrodes 402, 404 are oriented parallel to one another (i.e., both electrodes are elongated in a same first direction 406, or in other words, have longitudinal axes of symmetry, also referred to as major axes of symmetry, that are oriented in the same first direction).

[0096] In one embodiment, the first electrode 402 is adjacent to the backside 204 (also referred to as the backside surface 204) of the carrier mesh 104, the second electrode 404 is adjacent to the frontside 208 of the carrier mesh 104, and the second electrode 404 is at least partially encased in a dielectric 408. In embodiments, the dielectric 408 is formed of (homogeneously-distributed) dielectric plastic material. In one embodiment, and as measured from the second electrode 404, the dielectric extends a width/thickness in at least in a second direction 412 (i.e., in the z direction) towards the first electrode 402, where the second direction 412 is perpendicular to the first direction 406. In an embodiment, the air gap g 405 is formed between a bottom edge 413 of the dielectric (i.e., the edge or surface closest to the first electrode 402) and the first electrode. As illustrated, the air gap g 405 is partially occupied by the carrier mesh 104 with the integrated fibers 106, which is being fed though the air gap 405 by the conveyor assembly 107.

[0097] The conveyor assembly 107 is configured to move the carrier mesh 104 with the integrated fibers 106 in a third direction 414 (i.e., into or out of the plane of FIG. 4) that is orthogonal to both the first and second directions 406, 412. In one embodiment, the conveyor assembly 107 transports the carrier mesh 104 through the air gap 405 at a speed between 5-15 m/min, preferably between 6-12 m/min, and more preferably between 6-9 m/min. In one embodiment, the speed is dependent upon one or more parameters of the dispensing unit 116 (e.g., a rate at which the backing layer 302 is applied to the plasma-activated backside 204 of the carrier mesh 104).

[0098] In another embodiment, the conveyor assembly 107 is configured to move the carrier mesh 104 through the air gap 405 at a manually-adjustable and/or an automatically-adjustable speed. For example, the speed may be adjusted by operator input to the control unit 114, and/or the control unit 114 may include software that is configured to automatically determine and/or adjust the speed of the conveyor assembly 107 based upon data input by an operator and/or upon data collected from system sensors, e.g., rate of application of the backing layer mixture 118 from the dispensing unit 116 and/or power applied to the backside 204 of the carrier mesh 104 as a plasma discharge from the DBD device 112. Optionally, the system 112 may comprise one or more distance sensors configured to identify if the carrier mesh comprises any elevations or attached objects which might, upon reaching the first electrode, collide and potentially damage the first electrode. In this case, the controller operatively coupled to the distance sensor(s) to increase the width of the air gap or to stop the movement of the carrier mesh as to prevent the first electrodes being damaged. The distance sensors can be, for example, optical sensors, e.g., cameras, or laser-based distance sensors, or ultrasonic signal-based distance sensors, capacitive distance sensors, etc.

[0099] In one embodiment, a single electrode, i.e., the first electrode 402 of the DBD device 112, is electrically coupled to the control unit 114 via a power lead 416. The power lead 114 supplies a voltage to the first electrode, resulting in the DBD device 112 generating a plasma discharge, also referred to as a dielectric barrier discharge, that is directed to (i.e., applied to) the backside 204 of the carrier mesh 104 for plasma-activating the backside 204. In other embodiments, two or more power leads 416 (not shown) are coupled between the control unit 114 and two or more positions along the first electrode 402.

[0100] In another embodiment, the DBD device 112 includes a support structure 418 that is configured to be non-electrically (e.g., mechanically) coupled to the first electrode 402 at one or more positions along the first electrode 402, or as illustrated, at two end points 420 of the first electrode 402, for supporting a positioning of the first electrode 402 with respect to the second electrode 404 and with respect to the bottom edge 413 of the dielectric 408 that at least partially encases the second electrode 404, and for setting a width of the air gap g 405. In one embodiment, the support structure 418 is configured to be manually adjustable in at least a vertical direction (i.e., in the z direction 412). Control of the support structure 418 by the control unit 114 will be discussed in more detail further below.

[0101] In some embodiments, the thickness of the dielectric 408 is between 0.2 cm to 10.0 cm, e.g., about 2.0-3.0 cm. In other embodiments, given a known carrier mesh width wc 422, as measured from the backside 204 to the frontside 208 of the carrier mesh 104 in a state when the frontside of the carrier mesh rests on a surface, e.g. a roll, and the fiber portions to form the turf are compressed, the air gap g 405 has a width which results in a distance rg 424 measured between the backside 204 of the carrier mesh and the first electrode 402 that is typically less than 1.0 cm, e.g. less than 0.5 cm and preferably less than 0.3 cm. Preferably, the distance 424 of the first electrode(s) is chosen such that a direct contact of the first electrode(s) and the carrier mesh is avoided. However, applicant has observed that due to the uneven surface and the tuft rows, direct contact may not always be avoided, and in some use case scenarios, even a distance 424 of 0 mm, i.e., a basically contact-based configuration of the plasma discharge device, may successfully be used. Surprisingly, applicant has observed that even in case the first electrode occasionally or continuously touches the surface of the carrier mesh, the plasma activation effect is nevertheless distributed homogeneously over the whole length of the first electrode(s), and hence homogeneously over the whole area of the carrier mesh treated. This may be the result of the use of the dielectric enchasing the second electrode, because this dielectric typically has a higher dielectric constant than the material (greige good, carrier) transported through the air gap and prevents the first electrodes to discharge in case the first electrode(s) occasionally or continuously contact the greige good or carrier.

[0102] In embodiments, the first electrode 402, also referred to as a counter electrode, the second electrode 404 and the carrier mesh 104 each have at length 1 426 of 4 meters. However, the scope of the invention covers counter electrodes, electrodes and/or carrier meshes having different lengths (i.e., smaller and larger).

[0103] In one embodiment, the dielectric 408 is a hollow cylinder (or a partial cylinder) that is centered about and extended along a cylinder of metal used as the second electrode 404. However, the scope of the invention includes dielectrics having other shapes, such as elliptical or rectangular. In other embodiments, and particularly for hollow-cylindrically-shaped dielectrics having the second electrode 404 positioned at their respective longitudinal (i.e., major) axes of symmetry, the second electrode 404 including the dielectric 408 surrounds (or at least partially surrounds) the second electrode 404 and is vertically positioned (i.e., positioned in the z direction 412) within the DBD device 112 such that the frontside 206 of the carrier mesh 104 makes contact with the bottom edge 413 (or surface) of the dielectric (i.e., edge (or surface) closest to the first electrode 402) such that the complete cylinder 408 rotates about its longitudinal axis as the carrier mesh 104 is moved through the air gap 405 of the DBD device 112 by the conveyor assembly 107.

[0104] In one embodiment, the static frictional force between the frontside 208 of the carrier mesh 104 and the dielectric 408 is large enough to cause the dielectric 408 to rotate about the second electrode 404 as the carrier mesh 104 is moved through the air gap 405 of the DBD device 112 by the conveyor assembly 107 without any slippage between the portions of the dielectric 408 in contact with the frontside 208 of the carrier mesh 104 and the frontside 208 of the carrier mesh 104. Advantageously, neither the frontside 208 of the carrier mesh 104, nor the dielectric 408 surrounding the second electrode 404, build up a static electrical charge. However, if there is slippage (i.e., relative motion) between the carrier mesh 104 and those surface portions of the dielectric in contact with the carrier mesh 104, then the dynamic frictional forces cause by one material contacting and moving with respect to a second material may generate heat, static electricity, and a static voltage potential between the two materials, thereby compromising a uniform distribution of the dielectric barrier discharge (i.e., the plasma discharge) across the backside 204 of the carrier mesh 104, as well as compromising application of the discharge at desired controlled voltages and/or desired controlled temperatures.

[0105] The control unit 114 includes a controller 426, a positioning system 428, and a power source 430, such as a transformer. The controller 426 is configured to control the DBD device 112 for applying a dielectric barrier discharge to the backside 204 of the carrier mesh 104 as the carrier mesh 104 moves through the air gap 405 for plasma-activating the backside 204. In one embodiment, the controller 426 controls the DBD device 112 to continuously apply a plasma discharge to the backside 204 of the mesh 104 as the mesh 104 moves through the air gap 405. In one embodiment, the controller 426 is configured to enable the power source 430 to apply, via one or more power switches (not shown), a voltage of up to and including 40 kV to the first electrode 402 of the DBD device 112 via the power lead 416.

[0106] In an exemplary embodiment, the controller 426 controls the DBD device 112 to continuously apply a plasma discharge to the backside 204 of the mesh 104 as the mesh 104 moves through the air gap 405 at an energy density of between 0.5 J cm.sup.2 and 0.6 J/cm.sup.2. In one embodiment, the DBD device 112 delivers the plasma discharge at a power between 500 and 600 Watts as the conveyor assembly 107 moves the mesh at a speed of 6 m/min for applying an energy density of between 0.5 J cm.sup.2 and 0.6 J/cm.sup.2 to the backside 204 of the mesh 104. The energy density can be adjusted by controlling the speed of the conveyor assembly 107 and the applied power. For example, decreasing the applied power and/or increasing the conveyor speed reduces the energy density applied to the backside 204 of the mesh 104.

[0107] In one embodiment, the control unit 114 is configured to control the dielectric barrier discharge device 122 to apply the dielectric barrier discharge for plasma-activating the backside 204 by enabling the formation of covalent bonds between the backside 204 and the backing layer coating 302, as applied by the dispensing unit 116 after the backside 204 is plasma-activated, for providing increased binding between the fibers 106 of the carrier mesh 104 and the applied backing layer 302. In particular, the portions of the fibers exposed on the backside of the carrier mesh (e.g., for fibers tufted into the carrier mesh, as illustrated by FIG. 2, portions of the fibers 202 exposed in the tuft rows 210 on the backside of the carrier mesh), are activated by the plasma discharge (i.e., by the bombardment of the mesh backside 204 (i.e., the backside surface) by high energy ions from the plasma formed in the air gap 405), or in other words, enabling the mesh backside 204 (at an atomic/molecular level) to be receptive to the formation of covalent bonds with the backing layer 302, which is applied shortly thereafter.

[0108] In contrast to a corona discharge system, the dielectric 408 of the DBD device 112 limits current flow and distributes the plasma discharge more uniformly over the backside 204 of the carrier mesh 104, thereby enabling the formation of a more homogeneous distribution of covalent binding between the backside 204 and applied backing layer 302, resulting in an overall improvement in the strength of attachment between the backing layer 302 and the fibers 106 of the carrier mesh.

[0109] In one embodiment, the system 100 is configured, e.g., via selection of the speed of the conveyor assembly 107 and/or selection of distances between the DBD device 112 and the dispensing unit 116, such that the dispensing unit 116 applies the backing layer coating to a portion of the plasma-activated backside 204 of the carrier mesh 104 within a few hours or preferably a few minutes after plasma activation of that portion by the DBD device 112, so that a significant number of plasma-enhanced receptive sites are still available for forming respective covalent bonds with the backing layer 302 when applied. In one embodiment, a maximum time period for applying the backing layer 302 to a portion of the plasma-activated backside 204 of the carrier mesh 104 is 5 minutes after plasma activation of that portion by the DBD device 112.

[0110] In yet another embodiment, the positioning system 428 is coupled to the support structure 418 of the DBD device 112 for moving the support structure 418 in at least a vertical up-down direction (in direction 412). In one embodiment, the positioning system 428 is a distributed positioning system 428 that includes one or more of servos, actuators, switches (mechanical and/or electrical), signal/control lines for transmitting electrical, pneumatic and/or hydraulic control signals for operating the servos and actuators, and sensors, or any combination thereof, distributed throughout the system 100 for moving components of the system 100, such as moving the support structure 418 for adjusting/setting the width of the air gap 405. In other embodiments, the positioning system 428 is configured to also adjust/set other system parameters, without moving any of the system components, such as adjusting/setting the speed of the conveyor assembly 107 for moving the carrier mesh 104, via control/power signals to electrical motors for driving the conveyor assembly 107.

[0111] The controller 426 may be configured, e.g., with a user input interface, such that an operator may manually enter data that instructs the controller 426 to adjust the air gap 405, via the positioning system 428, to a desired width. The desired width of the air gap 405 may be based upon one or more of: the voltage to be applied to the first electrode 402, the speed at which the carrier mesh 104 is moved through the air gap 405, the thickness of the dielectric 408, the type of material of the dielectric 408 and/or carrier mesh 104, the width wc 422 of the carrier mesh, the distance rg 424 measured between the backside 204 of the carrier mesh 104 and the first electrode 402, or the ambient environment of the DBD device 112 (e.g., ambient temperature, humidity, etc.), or any combination thereof.

[0112] In another embodiment, or in addition to the embodiment of the controller 426 being configured with a user interface, the controller 426 includes software that is configured to automatically determine a desired width of the air gap 405 based on, e.g., operator input to the controller 426, as described above, and/or on data collected by system sensors (not shown) of the distributed positioning system 428. For example, the distribute positioning system 428 may optionally include a motion sensor and/or a width sensor for detecting the speed of the carrier mesh 104 through the air gap 405 and/or the width wc 422 of the carrier mesh 100 integrated with the fibers 106. Motion sensors are well known in the art and will not be discussed in further detail.

[0113] In one embodiment, a width sensor includes a vertically-moveable mechanical arm that moves in a vertical direction 412 as it remains in contact with the backside 204 of the carrier mesh 104 at a location in the system 100 before the carrier mesh 104 enters the air gap 405. Based on a current vertical position of the moveable arm, a known average width of the carrier mesh 104 integrated with the fibers 106, and the speed of the mesh 104 along the conveyor assembly 107, the controller 426 determines the desired width of the air gap 405 and instructs the positioning system 428 to continuously adjust the air gap width such that the distance rg 424 measured between the backside 204 of the carrier mesh 104 and the first electrode 402 is constant, or essentially constant.

[0114] Since carrier meshes may have some width irregularities, the controller 426, using the data received from the width sensor, corrects for width irregularities, thereby ensuring that the distance rg 424 remains essentially at a constant desired value when the plasma discharge is applied to the mesh 104 as the mesh 104 moves through the air gap 405.

[0115] In other embodiments, the width sensor of the positioning system 428 is a camera that captures images of either the backside 204 of the carrier mesh 104 or the entire carrier mesh 104 (bounded by the front and backsides 208, 204), as the carrier mesh 104 moves past the camera before the mesh 104 enters the air gap 405. The controller 426 receives the captured images, and using, e.g., edge detection software, detects the vertical position of the backside 204 (and/or frontside 208) of the mesh 104, determines width irregularities in the mesh 104, and instructs the positioning system 428 to adjust the position of the first electrode 402 to keep the distance rg 424 at an essentially constant desired value as the mesh 104 moves through the air gap 405 to receive the plasma discharge.

[0116] As mentioned above, the system 112 may comprise one or more distance sensors for identifying the distance of elevations or objects which might collide with the first electrode. The controller may be configured to adjust the width of the airgap, e.g. via the position of the first electrode, based on the measurement data obtained from the distance sensors, such that a collision is prevented.

[0117] In embodiments in which the carrier mesh 104 includes the fibers 106 tufted into the backside 204, the distance rg 424 is measured between the portions of the fibers elevated above the backside 204 of the mesh 104 (as a result of the fibers being tufted into the mesh 104) and the first electrode 402. In one embodiment, the backside 204 forms a non-planar surface, where the tuft rows 210 form tufted regions elevated above the other non-tufted regions of the carrier mesh 104. However, the scope of the present invention covers carrier meshes 104 including other types of fiber integration. For example, in another embodiment, the carrier mesh 104 includes fibers incorporated by weaving the fibers into the carrier mesh. Whether the fibers are woven or tufted into the carrier mesh 104, the scope of the present invention covers planar and non-planar carrier mesh backsides 204. In one embodiment, the carrier mesh 104 is positioned on the carrier assembly 107 such that the tuft rows 210 are parallel to the direction of motion of the carrier mesh 104 though the DBD device 112.

[0118] FIG. 5 shows a z-x cross-sectional view of the DBD device 112 of FIG. 1, according to an embodiment of the invention. Reference numbers that are the same as those used in conjunction with FIGS. 1 and 4 reference the same elements. For ease of illustration, the support structure 418 and power lead 416 are not shown.

[0119] As illustrated, the DBD device 112 includes the second electrode 404 surrounded by the dielectric 408, formed as a hollow cylinder of dielectric material having a bottom edge 413 (i.e., portion of dielectric surface) contacting the frontside 208 of the carrier mesh 104. The whole cylinder comprising the second electrode and the dielectric is rotatable about the longitudinal axis of the whole cylinder. The DBD device 112 includes the first electrode 402, and may optionally include one or more additional first electrodes, all aligned parallel to one another (all longitudinally extended in the same direction). In the exemplary embodiment as illustrated, the DBD device 112 includes two additional first electrodes 502 and 504. However, the scope of the invention covers other embodiments having any number of parallel oriented first electrodes. Although not shown, each of the optional first electrodes 502 and 504 are coupled to the support structural 418 for support and vertical location adjustment, and with the power supply 430 via the power lead 416. Preferably, the first electrodes are galvanically decoupled from each other.

[0120] Advantageously, by using two (or more) parallel first electrodes, e.g., 402, 502, 504, plasma activation of the backside 204, as well as binding between the backside 204 and the applied backing layer 302, is increased due to the increase in total surface area provided by the additional first electrodes, resulting in an increase in the volume of air in the portion of the air gap 405 (that is not occupied by the mesh 104, (i.e., the volume contained within the distance rg 424)) that is transformed into a plasma before the transformation is halted by plasma saturation within the air gap. That is, the volume of air in the gap that can be transformed into a plasma is limited by the number of first electrodes, independent of increasing the applied power above a maximum value corresponding to the onset of plasma saturation. For example, a DBD device including one first electrode may result in maximum binding at 600 Watts, with no appreciable improvement in binding at powers greater than 600 Watts. However, a DBD device having two or more first electrodes operating at 600 Watts has a greater volume of air in the gap before plasma saturation of the gap occurs, and thus an improvement in binding at 600 Watts in comparison, and a possible additional improvement in binding for powers greater the 600 Watts up to a higher maximum power limit. A further advantage may be that in case the voltage field of one first electrode partially breaks down or is reduced due to a contact with the carrier mesh and a resulting partial discharge, the voltage field to the other first electrode(s) remains unaffected, thereby ensuring that the plasma-activation is

[0121] According to additional embodiments, a system of the present invention includes the dielectric barrier discharge device 112, the conveyor assembly 107, the control unit 114 and the dispensing unit 116 of FIG. 1, either formed as a separate production line system independent of the production line system 100, or formed as a system including the individual components 112, 107, 114, and 116 (or alternatively the individual components 112, 114 and 116) configured not as a production line or part of a production line.

[0122] FIG. 6 shows an overhead perspective view of the DBD device 112 of FIG. 1, according to an embodiment of the invention. The DBD device 112 includes two first electrodes 602, 604, where each first electrode is the same as the first electrode 402 (FIG. 4), the dielectric 408 formed as a cylinder that completely surrounds (i.e., encases) the second electrode 404, which is not visible, and the air gap 405 through which the carrier mesh 104 (not shown) is moved. The two first electrodes 602, 604 preferably are parallel metal wires galvanically decoupled from each other.

[0123] FIG. 7 illustrates a method 700 for method of manufacturing an artificial turf, according to an embodiment of the invention.

[0124] In step 702, a carrier mesh 104 is moved through an air gap 405 formed between a first electrode 402 and a second electrode 404 of a dielectric barrier discharge device 112. The carrier mesh 104 includes a backside 204, and the carrier mesh 104 includes fibers 106 integrated such that a portion 202 of the fibers 106 are exposed on the backside 204.

[0125] In step 704, a dielectric barrier discharge is applied to the backside 204 of the carrier mesh 104 for plasma-activating the backside 204.

[0126] In step 706, a backing layer 302 is applied to the plasma-activated backside 204 of the carrier mesh 104 for providing an artificial turf.

[0127] FIG. 8 is an illustration of the plasma activation process. It shows the side of a carrier mesh 960 comprising the tuft rows while the carrier mesh is moved through the air gap between the first electrode 958 and the surface of the dielectric (below the carrier mesh, not shown). In the depicted example, the first electrode is a metal profile having the shape of a rod and being held at a specific, short distance from the surface of the carrier mesh via electrically conductive bars 954. The depicted rod may have a diameter of e.g., 0.2 to 3 mm. The bars may be attached to a frame 956 and may be connected via a cable 952 to a voltage source. As can be inferred from FIG. 8, the first electrode may in some spots be in direct contact with the carrier mesh. Nevertheless, applicant has observed that the plasma activation results in an improved tuft bind and that this effect is homogeneously distributed over the whole surface of the plasma-treated carrier mesh.

[0128] FIGS. 9A and 9B show experimental data obtained for five different artificial turfs. Some properties and process parameters are indicated in respective columns, e.g., stitches per meter, the applied power, the conveyor speed etc. The voltage used for the plasma activation of the turfs 1-5 was, respectively: 32.2 kV, 33 kV, 33.6 kV, 33.6 kV and 33.6 kV. Some turfs comprised smooth fibers, others comprised texturized fibers as indicated in column sample fiber type.

[0129] After having plasma-activated the turfs, the liquid polyurethane backing was applied and solidified in an oven. Then, the tuft withdrawal force was measured. Some measurements were performed 24 h after the manufacturing process. Other tuft withdrawal force measurements were performed after 14 days of immersing the sample in a 70 C. water-bath (simulated aging) or after 4 weeks (incubation in dry state, no water-bath). The time point of performing the respective measurement is also indicated in the column sample fiber type.

[0130] The tuft withdrawal force measurements were performed as specified in FIFA Test Method 26 (Test Manual I-Test Methods: 2015 Edition-FIFA Quality Programme for Football Turf), page 81. The FIFA test 26 comprises selecting and withdrawing one whole tuft and measure the force required to completely withdraw the tuft along a predefined path.

[0131] For example, a first section of the first artificial turf was plasma-activated using a dielectric barrier discharge machine. The machine was configured to generate a voltage field of 32.2 kV between the first and second electrodes for applying 500 Watts only onto a first section of the carrier mesh. Two other sections of the same first artificial turf were not plasma-treated (0 Watts) and used as controls. The tuft withdrawal force of the first section of the first artificial turf was measured at different times (lines 1, 4, 7) after the manufacturing process. Likewise, the tuft withdrawal force of the two other sections of the first artificial turf used as controls was measured at different times (lines 2+3, 5+6, 8+9) after the manufacturing process.

[0132] Three measurements were made on each of the three different sections of the artificial turf (bundle withdrawal force for sample 1, sample 2 and sample 3).

[0133] In addition, the average and standard deviation were computed for the measurement values obtained for each section of the first and the four other artificial turfs. As shown, the average force required to pull out a fiber from the carrier mesh in the plasma activated section is 56 N 24 h after the manufacturing, and the average force required to pull out a fiber from the carrier mesh in the non-plasma activated control sections is 34 and 37 N 24 h after the manufacturing of the first artificial turf. The measurements were repeated after 14 days of aging in a 70 C. water bath and after 4 weeks after manufacturing (storing the artificial turf in dry state, no water-bath). The water-based aging process comprised immersing the five artificial turfs in hot water (70 C.) in accordance with DIN EN 13744. According to DIN EN 13744, the artificial turf to be tested is to be completely immersed in a water bath having a temperature of 70 C. plus/minus 2 C. for 334 to 338 hours (14 days). Then, the artificial turf sections to be tested were taken out of the water and prepared for performing a tuft withdrawal force test as specified in FIFA Test Method 26 (Test Manual I-Test Methods: 2015 Edition-FIFA Quality Programme for Football Turf), page 81.

[0134] A second artificial turf was plasma-activated and used for collecting tuft withdrawal measuring data analogously, whereby the dielectric barrier discharge device was configured to apply 600 Watt on a first section of the second artificial turf while two other sections were not plasma-treated and used as controls. As for the first artificial turf, three measurements each were made on three different sections of the artificial turf (i.e., a section plasma-activated by application of the plasma discharge at 600 Watts, and two control sections (1 and 2) that did not receive the plasma discharge (i.e., 0 Watts)). As shown, the average force required to pull out a fiber from the carrier mesh in the plasma activated section is 68 N 24 h after the manufacturing, and the average force required to pull out a fiber from the carrier mesh in the non-plasma activated control sections 1 and 2 is 35 and 39 N 24 h after the manufacturing.

[0135] A third, fourth and fifth artificial turf was (partially) plasma-treated and analyzed for obtaining tuft withdrawal measurement data as described above, whereby 700 Watts were used to plasma-activate the first section of the respective turf.

[0136] The measurement results show that the fibers of the plasma-activated sections of the artificial turfs are bound more strongly to the backing-layers in comparison to the fibers of the control sections (non-activated sections), with the rate of increase in tuft-binding per unit applied power decreasing as the applied power approaches 700 Watts. A further increase in applied power results in negligible increase in tuft-binding, due to plasma-saturation of the gap. This observation was observed consistently in the measurement data obtained from all five artificial turfs shortly and several weeks after the manufacturing. In general, artificial turfs having fibers of smaller gauge, smaller pile height, and smaller number of fiber stiches per meter resulted in weaker tuft binding. The plasma-activation consistently resulted in a tremendous improvement of tuft binding over the non-activated sections.

[0137] A comparison of the tuft withdrawal forces observed 24 h after manufacturing with the test data obtained 14 days and 4 weeks after manufacturing further reveals that the tuft binding was stable and did not significantly deteriorate during the 14 days water bath at 70 C. or during the 4 weeks storage in dry state.

[0138] A comparison of the standard deviations of the bundle withdrawal forces of the untreated and the plasma-treated pieces of the artificial turfs (see the two rightmost columns and the line mean of standard deviation) also reveals that the standard deviation of the plasma-treated samples was significantly smaller than that of the non-treated controls. This implies that the plasma-activation was able to provide a tuft bind which was not only significantly stronger than in the un-treated controls, but which was also more homogeneously distributed compared to the tuft bind of the untreated controls.

[0139] Furthermore, a long-time test for the turf number 3 for the section treated with 700 Watt was performed seven weeks after production (not shown). The tuft withdrawal force obtained after seven weeks was basically identical to the tuft withdrawal forces measured after two weeks, showing that the plasma activation resulted in a stable, long-lasting enhancement of the tuft bind.