ARTIFICIAL TURF AND METHOD FOR PRODUCING A TURF OF THIS TYPE

Description

[0001] The present invention firstly relates to an artificial turf comprising a ground fabric made from synthetic ground warp yarns and synthetic weft yarns and a number of plastic blades of grass protruding from the ground fabric in the shape of pile burls which succeed one another in the warp direction and which each comprise two pile legs. Secondly, the present invention relates to a method for producing artificial turf of this type.

[0002] Artificial turf is being used increasingly often as a replacement for natural turf because:

• the climatic conditions are not always suitable for natural turf;
• the load to which the natural turf is subjected (during sports events) damages the playing field, which makes it necessary to leave considerable intervals before using the playing field again;
• natural turf requires a lot of care and attention.

[0003] It is well known to produce artificial turf in which plastic fibers (blades of grass) are connected to a carrier material in which the plastic blades of grass preferably protrude from the carrier material at right angles. The plastic blades of grass are generally hard and smooth plastic fibers, such as polyolefins (polyethylene, polypropylene and mixtures) or polyamides.

[0004] Usually, the carrier material is a textile cloth through which the plastic blades of grass are tufted. This means that a plastic blade of grass is pushed through the cloth by means of a needle to form a loop. On the other side of the textile cloth, a hook takes over the loop which has been produced and takes this loop to the desired level. The loop is then usually cut through, resulting in the formation of two upright blades of grass.

[0005] When producing artificial turf in accordance with the above-described manner, the yarns, and particularly those which form the blades of grass, constitute the main costs of the product. Solutions which result in artificial turf with the same performance while using less yarn will considerably reduce the cost price and are therefore interesting from an economic point of view.

[0006] International patent application WO 2004057111 describes the refinement of distributing the plastic blades of grass uniformly across the carrier material by selecting the distance between the rows of piles and the distance between the piles in the same row to be approximately equal and, in addition, to select this distance to be at least 10 mm. This means that only a limited number of yarns have to be used to achieve an optimum distribution. Artificial turf of this type has the drawback that, in order to keep the distance between the rows of blades of grass at at least 10 mm, the plastic blades of grass themselves have to be made from relatively thick filaments or from a considerable number of filaments (e.g. 8 x 1500 dtex or 8 x 2000 dtex), which are thus inserted into the artificial turf in the same position. This even distribution of large numbers of filaments ultimately results in a distribution of the plastic blades of grass in the artificial turf which is not really uniform on a monofilament level. The limit on the number of blades of grass in the artificial turf by means of the abovementioned large intermediate distance, in combination with the relatively large blades (e.g. determined by the number of filaments), results in a considerable consumption of grass blade material in order to achieve certain playing properties, such as for example a maximum roll of the ball. This means that a ball on a field which is rolled onto the turf from a height of 1 meter at an angle of 45° has to come to a standstill within a certain distance, e.g. 8 meters or 10 meters, in order to approach the characteristics of natural turf.
Furthermore, it should be noted that the process of tufting the plastic blades of grass currently has the limitation that not less than 120 tufts per meter can be produced in the tuft cloth direction so that there are sufficient loops on the hook and so that, when the subsequent tufts are produced, the pile of the previous loops is not pulled back resulting in very irregular pile or no pile at all. This makes it impossible to produce artificial turf with tuft densities below 10 000 tufts/m² having an even spacing between the various tuft rows.

[0007] JP A-51-47165 provide a method for manufacturing an artificial turf which comprises a double fabric structure incorporating flat pile yarns. According to JP A-51-47165, the surface of the base fabric is fully and efficiently covered by the pile yarns and a better appearance and cushion similar to the natural turf are realized in spite of that the mass thereof is relatively small.

[0008] Product leaflet Textile Industry SRX82 Van de Wiele, July 1985 describes a synthetic grass obtained by face-to-face weaving method and comprising a ground fabric and a number of plastic blades of grass protruding from the ground fabric which are tied up into the ground fabric e.g. by means of a W weave.

[0009] It is an object of the invention to provide an artificial turf which uses fewer plastic blades of grass and has properties, such as for example regarding roll of the ball, which are similar to the known artificial turf.

[0010] The object of the invention is achieved by providing an artificial turf consisting of a ground fabric made from synthetic ground warp yarns and synthetic weft yarns and a number of plastic blades of grass protruding from the ground fabric in the shape of pile burls which succeed one another in the warp direction and which each comprise two pile legs, in which at least three and at most nine weft yarns are inserted between two successive pile legs of a pile burl, and at least three weft yarns between the pile legs of successive pile burls. In particular, the two pile legs of a pile burl are tied up around a different weft yarn which are both situated between these two pile legs.

[0011] The main difference to the prior art is the fact that, during tufting, the pile legs of a tuft burl (the two legs of a cut tuft loop) lean against one another and are thus situated at virtually the same spot in the cloth. On the back of the tuft cloth, the pile leg of a tuft loop is connected to a pile leg of a subsequent tuft burl, the second pile leg of which also leans against said leg. In this manner, pile warp yarn runs along the back of the fabric in the tuft direction over virtually the entire length of the tufted cloth. With the artificial turf according to the invention, the distance on the back over which pile yarn extends is virtually half the total length. This leads to a significant saving in raw material for the pile warp yarns because there is both less material on the back and also because fewer blades of grass are required to achieve the same performance of the artificial turf due to the improved distribution of the plastic blades of grass.

[0012] With a preferred artificial turf according to the invention, the plastic blades of grass protruding from the ground fabric are tied up into the ground fabric by means of a W weave. In this case, the part of the plastic blade of grass which runs on the back of the fabric does not run from one pile leg to the other pile leg on the back of the fabric, but is tied up over one or more weft yarns on the side of the artificial turf pile. This has the advantage that the plastic blades of grass are fastened well in the ground fabric.

[0013] With a more preferred artificial turf, for each pile burl, the plastic blade of grass is tied up over at least two weft yarns which are situated between the pile legs of this pile burl on the side of the artificial turf of the fabric. This is in particular achieved by means of a 5/12 W weave in which there are 5 weft yarns between the two pile legs of a pile burl.

[0014] According to another preferred embodiment of the artificial turf according to the invention, for each pile burl, the plastic blade of grass is tied up over three weft yarns which are situated between the pile legs of this pile burl on the side of the artificial turf of the fabric. This is in particular achieved by means of a 7/16 W weave in which there are 7 weft yarns between the two pile legs of a pile burl.

[0015] In a particular embodiment of the artificial turf, the pile legs of adjacent rows of piles are offset with respect to one another. This is preferably achieved by means of a satin weave, thus resulting in a further improvement of the distribution of the pile burls. Examples thereof are: 5/12 W weave in satin 6; 7/16 W weave in satin 4; 7/16 W weave in satin 8. This method makes it possible to produce the artificial turf in a more efficient manner for an even distribution than without this offset.
In the case of an artificial turf with 6400 blades of grass/m² and with equidistant rows in both directions, 80 rows of piles/m will be distributed in the weft direction (determined by the weaving reed) and 40 pile burls/m (being 80 pile legs/m) will be used in the warp direction with the method without offset.
By using an offset, it is possible to produce the same 6400 blades of grass/m² using 160 rows of piles/m in the weft direction and only 20 pile burls/m, being 40 pile legs/m, if the pile legs of the adjacent row are offset by half the distance between two pile legs. As a result of the offset, there are only 80 pile legs per row in the warp direction. In the next row, over half a distance between two pile legs, are again 80 pile legs per row. Only half as many weft yarns are required in order to achieve these 20 pile tufts/m and consequently the fabric is produced twice as fast.
By applying the same method using 113 rows of piles/m and 28.25 pile burls/m, resulting in 56.5 pile legs/m, an even better uniform distribution is achieved in the two directions with in each case 56.5 artificial turf blades/m. Compared to the method using 80 rows of piles/m without offset, this method still uses a significantly smaller number of weft yarns per running meter and the artificial turf can still be produced more quickly for an even distribution.

[0016] In a most preferred embodiment of the artificial turf according to the invention, said turf is woven according to a face-to-face weaving method.

[0017] It is another object of the present patent application to provide a method for producing an artificial turf comprising a ground fabric and a number of plastic blades of grass protruding from the ground fabric, in which a bottom and a top fabric are woven according to a face-to-face weaving method, in which the fabrics are made from synthetic weft yarns, synthetic ground warp yarns and grass blade-forming pile warp yarns by means of which pile burls with in each case two pile legs are formed alternately in both fabrics, in which, in each fabric, each pile leg of a pile burl of a plastic blade of grass in a row in the warp direction is separated by at least three and at most nine weft yarns from the next pile leg of a plastic blade of grass in this row, and at least three weft yarns between the pile legs of successive pile burls.

[0018] After a pile burl has been formed in the one fabric, a pile burl is formed in the other fabric using the face-to-face weaving technique before the plastic grass blade yarn again forms pile in the one fabric. If the two pile legs of the pile burl in the other fabric are also separated by at least three weft yarns from one another, there are also at least three weft yarns between the pile legs of successive pile burls in the same fabric. (With 5/12 W weave, there are seven weft yarns inbetween; with 7/16 W weave, there are nine weft yarns inbetween).

[0019] Compared to the known techniques for producing artificial turf, the method according to the invention offers the following advantages:

• When using, both during weaving and during tufting, plastic blades of grass of the same thickness and the same pile burl density, the plastic blades of grass (the consumption of which is nearly identical in both situations) in the artificial turf according to the invention are distributed over twice as many evenly distributed physical points, as a result of which the performance of the artificial turf improves for the same amount of material (this means that in order to achieve the same performance of the artificial turf, the pile burl density can be reduced which results in a lower consumption of plastic grass blade material);
• When using, both during weaving and during tufting, plastic blades of grass of the same thickness and the same pile burl density, the method according to the invention uses less material as the distance between the two pile legs of a pile burl is only half that of the distance between the pile legs during tufting, as a result of which the material consumption on the back is reduced;
• When using relatively thick yarns with a relatively low pile burl density and if weaving is carried out at a consumption of pile material which corresponds to the consumption of pile material of tufted artificial turf, said relatively thick integrally formed yarns will result in a better stiffness, a better resilience and a better roll of the ball than is the case when the pile legs of the tufts are placed next to one another. The improved properties and equal consumption again result in less raw material being required in order to achieve the same performance of the artificial turf;
• The plastic blades of grass used are usually composed of several filaments which are bundled. The relatively thick plastic grass yarn may be composed of relatively thick filaments of which fewer are ultimately required. This further increases the resilience and playing properties, as a result of which the material consumption can be reduced further while retaining the same playing properties.

[0020] According to a preferred method according to the invention, the purpose of the method is to produce an artificial turf as described above.

[0021] In the detailed description given below, the abovementioned characteristics and advantages of an artificial turf and the method for producing it according to the invention are explained in more detail. The purpose of this description is only to explain the general principles of the present invention in more detail and therefore nothing in this description should be interpreted as limiting the area of application of the invention or of the patent rights claimed in the claims.

[0022] Reference numerals are used in this description to refer to the attached figures 1 to 3, in which:

• figure 1 shows a diagrammatic representation of an artificial turf with tufted blades of artificial grass according to the prior art;
• figure 2 shows a cross section through the artificial turf represented in figure 1;
• figure 3 shows a diagrammatic representation of an artificial turf according to the invention.

[0023] Due to their high durability, artificial turfs are being used increasingly often in sports these days. In addition, heavily used artificial turfs do not suffer from a loss of quality due to weather conditions or due to being played on, so that such fields can be played on virtually without restriction.

[0024] The prior-art artificial turf pitches are composed of tufted artificial turf. This known artificial turf, as illustrated in figures 1 and 2, comprises a base fabric and a number of plastic blades of grass (5) protruding from this base fabric. The plastic blades of grass (5) are connected to the base fabric (for example a textile cloth) by means of reciprocating tuft needles and hooks, onto which the tuft burls are transferred from the needles. However, this known technique has the drawback that in each case two tuft legs (5) of a plastic blade of grass are positioned right next to one another, which indeed do not act a single blade of grass of double thickness due to the limited distance between them. This can be seen in figure 2.

[0025] The artificial turf (1) according to the present invention and as illustrated in figure 3 consists of a ground fabric and a number of plastic blades of grass (2) protruding out of the ground fabric in the shape of pile burls which succeed one another in the warp direction and which each comprise two pile legs. The ground fabric consists of synthetic, moisture-resistant ground warp yarns and weft yarns (3). In addition to the plastic blades of grass and the weft yarns, it is also possible to provide tension warp yarns (4) in the ground fabric, which ensure that the weft yarns are layered, as well as binding warp yarns (not illustrated in the figure) which regularly intersect with each other, the weft yarns being situated between the intersecting binding warp yarns.

[0026] The invention is characterized by the fact that at least three and at most nine weft yarns (3) are inserted between two successive pile legs (2a). In the case of the artificial turf illustrated in figure 3, five weft yarns (3) are inserted between two successive pile legs. This is preferably achieved by means of the technique of the W weave in face-to-face weaving: this means that the plastic blades of grass consist of pile burls which each consist of two pile legs, with at least three weft yarns (3) and at most nine weft yarns being present between the pile legs and there also being at least five weft yarns and at most eleven weft yarns between the pile legs of successive pile burls. Each pile leg (2a) is tied up around a different weft yarn (3a) which are both situated between the two pile legs. Furthermore, the plastic grass blade section (2b) which connects the two pile legs to one another is tied up in the ground fabric over at least one additional weft yarn (3b) between the two pile legs.

[0027] When artificial turf is woven in accordance with the method according to the invention and according to the face-to-face weaving technique in a W weave, the two pile legs (2a) of a tuft are separated from one another over a number weft yarns and therefore over a certain distance. The pile yarn (the plastic blade of grass) then moves to the other fabric in order to also insert two pile legs (2a) in a W weave as a plastic blade of grass (2) and to return to the first fabric in order to insert two pile legs (2a) at a distance from one another as a plastic blade of grass (2), again in W weave.
Where the two pile legs together form one tuft (one blade of grass) in one location during tufting, according to the method of the present invention, the same amount of pile is produced in two locations which are a distance apart. With the same material consumption as in the prior art and with the same distance between the rows in the warp direction for weaving as between the needles during tufting, in accordance with the method according to the invention there will be blades of grass in twice as many locations in the warp direction compared to the tufted turf where the blades of grass are situated in the direction in which the tuft cloth moves.
When turf is woven according to the current 1/2V technique, the two pile legs are also next to one another separated by one weft yarn, as a result of which the two pile legs are virtually next to one another and appear as a single blade of grass. Compared to this prior art, the method of the invention offers the same advantages as the prior art with respect to tufting, especially if the 1/2V technique is used for intermediate distances between the pile legs of more than 10 mm.

[0028] Furthermore, only that part of the plastic blade of grass which runs between two upright plastic blades of grass of the same pile burl runs on the back of the fabric, while there is no material on the back between two upright plastic blades of grass from a different pile burl, thus resulting in a further reduction in the consumption of material.

Claims

1. An artificial turf (1) comprising a ground fabric made from synthetic ground warp yarns and synthetic weft yarns and a number of plastic blades of grass (2) protruding from the ground fabric in the shape of pile burls which succeed one another in the warp direction (K) and which each comprise two pile legs (2a) characterized in that at least three and at most nine weft yarns (3) are inserted between two successive pile legs (2a) of a pile burl, and at least three weft yarns between the pile legs of successive pile burls.

2. The artificial turf (1) as claimed in claim 1, characterized in that the plastic blades of grass (2) protruding from the ground fabric are tied up into the ground fabric by means of a W weave.

3. The artificial turf (1) as claimed in claim 1 or 2, characterized in that, for each pile burl, the plastic blade of grass (2) is tied up over at least two weft yarns (3) which are situated between the pile legs (2a) of this pile burl on the side of the artificial turf of the fabric.

4. The artificial turf (1) as claimed in one of the preceding claims, characterized in that, for each pile burl, the plastic blade of grass (2) is tied up over three weft yarns (3) which are situated between the pile legs (2a) of this pile burl on the side of the artificial turf of the fabric.

5. The artificial turf (1) as claimed in one of the preceding claims, characterized in that the pile legs (2a) of adjacent rows of piles are offset with respect to one another.

6. The artificial turf (1) as claimed in one of the preceding claims, characterized in that said turf (1) is woven according to a face-to-face weaving method.

7. A method for producing an artificial turf (1) comprising a ground fabric and a number of plastic blades of grass (2) protruding from the ground fabric, characterized in that a bottom and a top fabric are woven according to a face-to-face weaving method, in which the fabrics are made from synthetic weft yarns (3), synthetic ground warp yarns and grass blade-forming pile warp yarns (2) by means of which pile burls with in each case two pile legs (2a) are formed alternately in both fabrics, in which, in each fabric, cach pile leg of a pile burl of a plastic blade of grass (2) in a row in the warp direction (K) is separated by at least three and at most nine weft yarns (3) from the next pile leg of a plastic blade of grass (2) in this row, and at least three weft yarns between the pile legs of successive pile burls.

8. The method as claimed in claim 7, characterized in that the purpose of said method is to produce an artificial turf (1) as claimed in claim 1 to 6.

Ansprüche

1. Kunstrasen (1), umfassend ein Grundgewebe, das aus synthetischen Grundkettfäden und synthetischen Schussfäden und einer Anzahl von Kunststoffgrashalmen (2), die von dem Grundgewebe in Form von Polnoppen vorstehen, hergestellt ist, die aufeinander in Kettrichtung (K) folgen und die jeweils zwei Polschenkel (2a) umfassen, dadurch gekennzeichnet, dass mindestens drei und höchstens neun Schussfäden (3) zwischen zwei aufeinander folgenden Polschenkeln (2a) der Polnoppe und mindestens drei Kettfäden zwischen den Polschenkeln der darauf folgenden Polnoppen eingetragen werden.

2. Kunstrasen (1) nach Anspruch 1, dadurch gekennzeichnet, dass die Kunststoffgrashalme (2), die aus dem Grundgewebe vorstehen, im Grundgewebe mittels einer W-Bindung abgebunden sind.

3. Kunstrasen (1) nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass für jede Polnoppe der Kunststoffgrashalm (2) über mindestens zwei Schussfäden (3) umschlungen ist, die zwischen den Polschenkeln (2a) dieser Polnoppe auf der Seite des Kunstrasens des Gewebes gelegen sind.

4. Kunstrasen (1) nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass für jede Polnoppe der Kunststoffgrashalm (2) über drei Schussfäden (3) umschlungen ist, die zwischen den Polschenkeln (2a) dieser Polnoppe auf der Seite des Kunstrasens des Gewebes gelegen sind.

5. Kunstrasen (1) nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Polschenkel (2a) benachbarter Polreihen in Bezug aufeinander versetzt sind.

6. Kunstrasen (1) nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass der Rasen (1) gemäß einem Doppelstück-Webverfahren gewebt wird.

7. Verfahren zur Herstellung eines Kunstrasens (1), umfassend ein Grundgewebe und eine Anzahl von Kunststoffgrashalmen (2), die von dem Grundgewebe vorstehen, dadurch gekennzeichnet, dass ein unteres und ein oberes Gewebe gemäß einem Doppelstück-Webverfahren gewebt werden, wobei die Gewebe aus synthetischen Schussfäden (3), synthetischen Grundkettfäden und grashalmbildenden Polkettfäden (2) hergestellt sind, mit denen Polnoppen mit jeweils zwei Polschenkeln (2a) abwechselnd in beiden Geweben gebildet werden, wobei in jedem Gewebe jeder Polschenkel einer Polnoppe eines Kunststoffgrashalms (2) in einer Reihe in Kettschussrichtung (K) durch mindestens drei und höchstens neun Schussfäden (3) vom nächsten Polschenkel eines Kunststoffgrashalms (2) in dieser Reihe und mindestens drei Schussfäden von den Polschenkeln der nachfolgenden Polnoppen getrennt ist.

8. Verfahren nach Anspruch 7, dadurch gekennzeichnet, dass das Verfahren das Herstellen eines Kunstrasens (1) nach einem der Ansprüche 1 bis 6 bezweckt.

Revendications

1. Gazon artificiel (1) comprenant un tissu de fond constitué de fils de chaîne de fond synthétiques et de fils de trame synthétiques et d'un certain nombre de brins plastiques de gazon (2) qui font saillie à partir du tissu de fond sous la forme de noeuds de poil qui se succèdent les uns les autres dans la direction de la chaîne (K) et qui comprennent chacun deux jambes de poil (2a), caractérisé en ce qu'au moins trois et au plus neuf fils de trame (3) sont insérés entre deux jambes de poil successives (2a) d'un noeud de poil, et au moins trois fils de trame entre les jambes de poil de noeuds de poil successifs.

2. Gazon artificiel (1) selon la revendication 1, caractérisé en ce que les brins plastiques de gazon (2) qui font saillie à partir du tissu de fond sont entrelacés dans le tissu de fond au moyen d'une armure W.

3. Gazon artificiel (1) selon la revendication 1 ou 2, caractérisé en ce que, pour chaque noeud de poil, le brin plastique de gazon (2) est entrelacé sur au moins deux fils de trame (3) qui sont situés entre les jambes de poil (2a) de ce noeud de poil sur le côté du gazon artificiel du tissu.

4. Gazon artificiel (1) selon l'une quelconque des revendications précédentes, caractérisé en ce que, pour chaque noeud de poil, le brin plastique de gazon (2) est entrelacé sur trois fils de trame (3) qui sont situés entre les jambes de poil (2a) de ce noeud de poil sur le côté du gazon artificiel du tissu.

5. Gazon artificiel (1) selon l'une quelconque des revendications précédentes, caractérisé en ce que les jambes de poil (2a) de rangées voisines de poils sont décalées les unes par rapport aux autres.

6. Gazon artificiel (1) selon l'une quelconque des revendications précédentes, caractérisé en ce que ledit gazon (1) est tissé selon un procédé de tissage à double face.

7. Procédé de production d'un gazon artificiel (1) comprenant un tissu de fond et un certain nombre de brins plastiques de gazon (2) qui font saillie à partir du tissu de fond, caractérisé en ce qu'un tissu inférieur et un tissu supérieur sont tissés selon un procédé de tissage à double face, dans lequel les tissus sont constitués de fils de trame synthétiques (3), de fils de chaîne de fond synthétiques et de fils de chaîne de poil de formation de brins de gazon (2) au moyen desquels des noeuds de poil présentant dans chaque cas deux jambes de poil (2a) sont formées alternativement dans les deux tissus, dans lequel, dans chaque tissu, chaque tige de poil d'un noeud de poil d'un brin plastique de gazon (2) dans une rangée dans la direction de la chaîne (K) est séparée par au moins trois et au plus neuf fils de trame (3) de la tige de poil suivant d'un brin plastique de gazon (2) dans cette rangée, et par au moins trois fils de trame entre les jambes de poil de noeuds de poil successifs.

8. Procédé selon la revendication 7, caractérisé en ce que l'objectif dudit procédé est de produire un gazon artificiel (1) selon les revendications 1 à 6.

Drawing