WO2017137409A1

WO2017137409A1 - A method to manufacture a textile product, a use thereof and a device for applying the method

Info

Publication number: WO2017137409A1
Application number: PCT/EP2017/052691
Authority: WO
Inventors: Chris Reutelingsperger
Original assignee: Dsm Ip Assets B.V.
Priority date: 2016-02-08
Filing date: 2017-02-08
Publication date: 2017-08-17

Abstract

The present invention pertains to a method to manufacture a textile product comprising a primary carrier sheet and yarns that form a pile thereon, the method comprising providing a woven web as the primary carrier sheet, stitching the yarns through the woven web to form the pile on a first surface of the web and loops of the yarns at a second surface of the web, and transporting the web along a processing station, at which station a binding layer is provided at the second surface of the web to fasten the yarns to the web, wherein the method further comprises transporting the sheet upstream of the processing station over a first bowed roller, wherein the transport distance between the bowed roller and the centre of the processing station is less than 2 meters. The invention also pertains to a method to use a textile product obtained with the new method and a device for applying the said method

Description

A METHOD TO MANUFACTURE A TEXTILE PRODUCT, A USE THEREOF AND A DEVICE FOR APPLYING THE METHOD

GENERAL FIELD OF THE INVENTION

The present invention pertains to a method to a method to manufacture a textile product comprising a primary carrier sheet and yarns that form a pile thereon, the method comprising providing a web as the primary carrier sheet, stitching the yarns through the web to form the pile on a first surface of the web and loops of the yarns at a second surface of the web, and transporting the web along a processing station, at which station a binding layer is provided at the second surface of the web to fasten the yarns to the web. The invention also pertains to a method to use a textile product obtained with the new method and a device for applying the said method. BACKGROUND ART

In the manufacture of textile products, in particular carpet products such as broadloom carpet, mats, rugs, runners and carpet tiles, which comprise a primary carrier sheet, typically a non-woven textile material (such as a compressed fibrous sheet), and yarns that form a pile thereon, it is needed that the yarns are mechanically bonded to the sheet after application therein. The reason for this is that the application techniques, such as tufting and weaving (together referred to as stitching techniques) leave the yarns to be only loosely bonded to the primary carrier: they can be easily removed by a light pulling force by hand. A binding layer is therefore provided at the back of the primary carrier. With the provision of this binding layer, the ends or loops of the yarns at the back-surface (i.e. the surface opposite of the pile side) get bonded to the primary carrier.

In the art various options for the provision of such a binding layer are known. It is conventional practice to apply latex adhesives, foam backings, and the like, and to thereafter dry and/or cure the applied chemical agents at elevated temperatures by passing the treated textile substrate through a drying oven. In such drying and/or curing operation, the treated substrate is typically supported at each longitudinal edge thereof by one or two tenter chains (or tenter cables) each of which have tenter pins affixed thereto for securing said substrate to the respective tenter chain. Such chains or cables are in turn supported and guided through the oven by tenter rails (or tenter channels) and such chains or cables are in a continuous fashion, circulated or rotated through said oven, thereby transporting the treated substrate therethrough. This conventional method using lateral tenter chains has the important advantage that the tension in the textile product is relatively well-distributed such that no or hardly any local distortions arise. Non-woven webs appear to be ideally suitable to withstand the level of strain that arises due to the transport and action of the tenter chains, such that distortions of the primary carrier and thus of the ultimate pile side (face) of the end product can be prevented or at least minimised. That is why in particular for carpets, wherein local distortion may lead to a deformation of the pattern and thus non-usability of the end product, non-woven primary carriers are in most cases used.

Recent developments have provided for methods that do not need long curing operations and thus, can dispense with the long oven trajectories. One of such methods is known from EP1598476 (assigned to Klieverik Heli). This patent describes a method for manufacturing a textile product as indicated supra. In the method no use is made of a latex to anchor the yarns in place. The primary backing is fed (loops upwards) along a heated roller surface and its underside is pressed against the roller so the yarns and/or a hot melt adhesive applied as a powder will melt. It is described that after cooling, the yarns are firmly anchored to each other and the backing without the need for a latex polymer. In an embodiment pressure may be applied after heating (e.g. by a pressure roller) to the backing and piles in a direction perpendicular to the backing surface (i.e. from below) to press the plasticised yarns together to enhance their mutual adhesion, thus allowing the heated roller to be held at a lower temperature, below that at which the yarns would fuse by heat alone. This method provides the advantage that the intermediate backing can be easily recycled since the yarns and backing sheet can be made from the same polymer. There is no incompatible latex penetrated into the fibre piles. Due to the short processing length, no lateral tenter chains are needed to evenly guide the web along the process line. Simple rollers are used to guide the web. No mention is made of any other special measures to guide the web along the processing station.

WO 2012/076348 (Niaga) describes a method for manufacturing textile products that even improves the anchor strength of the yarn. In this method the first yarn bearing sheet is pressed against the edge of a heated blade, wherein this blade is stationary to provide an additional mechanical force on the molten yarn material in the longitudinal direction (i.e. a direction parallel to the length of the sheet, the process direction, also called machine direction or transport direction), which spreads the material of the yarn whilst it is still molten resulting in a stronger bond between the first sheet and the yarn. Also with this method, due to the short processing length, no lateral tenter chains are needed to evenly guide the web along the process line. Simple rollers are used to guide the web. No mention is made of any other special measures to guide the web along the processing station. In these known methods, as mentioned in the above referred to patent applications, it is preferred to use non-woven primary carriers. Although a woven web is less expensive for use as a primary carrier sheet, such webs are typically also less stable, easier to deform and can even be pulled apart when subjected to uneven (local) strain. Such webs typically distort due to strains that arise by transporting the web through the manufacturing process. Therefore, in particular when using the conventional process using tenter chains, in practice non-woven primary carrier sheets are being used. The more recent developed technologies such as described in EP 1598476 and WO 2012/076348 do not appear to need such tenter chains and in theory, woven primary carrier sheets could be used. However, using these technologies an inhomogeneous binding strength across the surface of the textile product may occur (some yarns are bonded more firmly then others). The reason for this inhomogeneous binding strength is not clear. Still, in many cases it will not be a problem either, in particular for the lower end applications. It may be a problem though for textile products that are prone to great mechanical stress such as entrance mats and carpets in hotel lobbies, airplanes, cruise ships, cars etc. For such high end applications therefore non-woven primary carriers are typically used.

OBJECT OF THE INVENTION It is an object of the invention to provide an adequate method to manufacture a textile product.

SUMMARY OF THE INVENTION In order to meet the object of the invention a method to manufacture a textile product as defined in the GENERAL FIELD OF THE INVENTION section has been devised, wherein the method comprises using a woven web as a primary carrier sheet and transporting the sheet upstream of the processing station over a first bowed roller, wherein the transport distance between the bowed roller and the centre of the processing station is less than 2 meters, in particular less than 1.95, 1.90, 1 .85, 1 .80, 1 .75, 1.70, 1 .65, 1 .60, 1.55, 1 .50, 1 .45, 1.40, 1.35, 1.30, 1 .25, 1.20, 1 .15 or even less than 1 .10 meters.

Surprisingly, when using a relatively unstable woven primary carrier, combined with a bowed roller (also called "bow roller") right before the processing station at which the binding layer is provided to fasten the yarns to the web, many of the prior art disadvantages are overcome or at least mitigated. Tenter chains, which might introduce too much strain for woven webs, appear to be not necessary to guide the web along the processing station, provided that a bowed roller is adjacent the processing station, i.e. within a transport length of 2 meters (i.e. the length over which the web is transported) going from the bowed roller to the centre of the processing station. In this method, the total processing length is thus less than 4 meters, typical for the more recent technologies such as known from EP 1598476 and WO 2012/076348 that do not rely on conventional latex, but typically use polymer adhesive to bind the yarns. It appears that using such short length in combination with a bowed roller, binding strength

inhomogeneity is not or hardly noticeable anymore, even when using a relatively unstable woven primary carrier. The reason for this is not quite clear. In hindsight, one may think that the bowed roller simply evens some existing creases. However, up to the present invention, it was thought that when running a woven web with a pile of yarns creases do not exist at all. First of all, such creases are simply not visible. More importantly however it was generally understood that a woven web with a pile of yarns thereon is principally resistant against creases since the pile yarns would prevent that the carrying web parts would overlap (which is needed to form a crease). Moreover, would such a crease exist, it was expected that it would have been visible. Still, knowing now that a bowed roller solves the problem of inhomogeneous binding, in hindsight, it might be that without using a bowed roller small creases do still exist, and that the bowed roller evens the creases. However, the fact that no mechanical distortion of the web is seen using the bowed roller (which is also called a spreading roller due to its ability to really spread, and thus macroscopically distort a running web) would contradict this. In any case, by using the bowed roller adjacent the processing station, despite the fact that such a roller introduces strain, it is possible to prevent or at least diminish inhomogeneous binding strength, while at the same time preventing that the web is distorted, even when a woven web is being used. This opens the way to use the relatively inexpensive woven primary carriers for high end applications of carpet products.

The invention also pertains to the use of a textile product obtainable in line with the above described method to cover a surface of a building or any other artificial or natural construction.

The invention also pertains to a device for use in manufacturing a textile product comprising a primary carrier sheet and yarns that form a pile thereon, the device comprising an upstream entrance for accepting the primary carrier sheet in the form of a web with the yarns stitched therethrough to form the pile on a first surface of the web and loops of the yarns at a second surface of the web, transporting means for transporting the web along a processing station, at which station binding means are present to provide a binding layer at the second surface of the web to fasten the yarns to the web, wherein the transporting means upstream of the processing station comprise a bowed roller for guiding the web, wherein the transport distance between the bowed roller and the centre of the processing station is less than 2 meters. The device according to the invention is suitable for various types of primary carriers, in particular for woven and non-woven carriers. It appears that the device is also advantageous when using a non-woven primary carrier since the bowed roller, in the current set-up of being positioned relatively close to the processing station, is able to guide the primary carrier with the pile of yarns thereon through the device without needing any tenter chains, whilst at the same time prevent distortion of the web up and until the processing station and hence, prevent distortion of the carpet patterns until the yarns are firmly bonded. DEFINITIONS

A textile product is a product that comprises textile (i.e. material made mainly of natural or artificial fibres, often referred to as thread or yarn), optionally with other components such as backing layers, carrier layers and/or adhesives. Textile products typically comprise an upper layer of pile attached to a backing (where the raised pile fibres are also denoted as the "nap" of the product), but may also be flat weave. Such products can be of various different constructions such as woven, needle felt, knotted, tufted and/or embroidered, though tufted products are the most common type. The pile may be cut (as in a plush carpet) or form loops (as in a Berber carpet).

A woven web is a continuous (i.e. long) length of a sheet-like material, which material is woven from yarns, fibres, tape or other thread-like material.

A polymer yarn is a yarn in which the yarn forming substance is a natural or synthetic thermoplastic polymer. The most widely used polymer yarns for textile products are polyamide and polyester yarns. Polyamide is mostly either PA6 or PA6,6 and the polyester used is mostly polyethylene terephtalate, generally referred to simply as PET. Typically, the polymers used for yarns have a melting point (Tm) of about 220 to 280°C and a glass transition temperature (Tg) of about 150 to about 180°C.

A loop of a yarn is a length of this yarn that may be curved away from the basic part of the yarn (not excluding that the loop is longer than the main part itself). For a textile product, the basic part of the yarn is the part that forms the upper, visible part of the product. For example, for a carpet this is the part of the yarns that forms the pile. For clothing, this is the part of the yarn that forms part of the outer surface of the clothing. The loop is the part that extends from the back surface of the (intermediate) product.

A bowed roller, also called a "banana roller", is a type of "spreader roller" having a curved stationary axle upon which a rotating sleeve(s) is mounted, typically over multiple bearing sets. The axle may have either a fixed or variable bow. The sleeve is typically a one-piece flexible tube of a soft synthetic composite, or may consist of numerous narrow metal shells. The amount of bow is typically between 0.1 and 2% (height of the arc vs length of the roller). A sheet is a substantially two dimensional mass or material, i.e. a broad and thin, typically, but not necessarily, rectangular in form, and inherently has two opposite surfaces.

Stitching is a method of mechanically making a yarn part of an object by stitches or as if with stitches, such as by tufting, knitting, sewing, weaving etc. A hot melt adhesive is a thermoplastic adhesive that is designed to be melted, i.e.

heated to transform from a solid state into a liquid state to adhere materials after solidification. Hot melt adhesives are typically non-reactive, crystalline and comprise low or no amount of solvents so curing and drying are typically not necessary in order to provide adequate adhesion.

EMBODIMENTS OF THE INVENTION

In a first embodiment of the invention, the transport distance between the first bowed roller and the centre of the processing station is less than 1 meter. It appears that with a shorter distance, there is more freedom in the type of bowed roller to use, that is, the type of sleeve, the bow of the axle (i.e. the height of the arc) etc. Apparently, at a shorter distance the type of roller is less critical to arrive at a proper balance between adequate guidance of the web, prevention of distortion of the woven web and a homogenous binding strength of the yarns when processing the web at the processing station. Particularly, the transport distance is less than 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.65, 0.60, 0.55 or even less than 0.5 meters. The distance is preferably above 0.1 meters, or even above 0.15, 0.20, 0.25, 0.30, 0.35, 0.40 or 0.45 meters to provide sufficient space to configure the bowed roller with respect to the processing station and to have sufficient process length at the station.

In another embodiment, at the processing station, a polymer material is present at the second surface of the web and heat is provided to melt the polymer material to provide the binding layer. Although an embodiment is foreseen wherein the polymer material is provided in pre-melted form at the processing station, it appears to be advantageous to have the material present at the second surface in non-melted form, and melt the material by the provision of heat at the processing station. Making sure non-melted material is present at the processing station is less complex than providing melted material to the station. In an embodiment, solid polymer material is applied right before the processing station in the form of a powdered material.

In a further embodiment the heat is provided by contacting a surface of a heated body with the second surface of the web. Providing the heat via contact with a hot body has shown to be an efficacious way of providing the heat needed to melt the polymer material. Although other means could be chosen, such as means that rely on heat influx by radiation, micro-waves, convection etc., applicant recognised that by contacting the web with a heated surface, and thus, relying on heat transfer via conduction, a relatively fast and reliable provision of heat can be arrived at. Moreover, by contacting the second surface of the web with the heated body, a mechanical spreading action of the binding layer can be obtained, possibly leading to a more even and compact binding layer. In yet a further embodiment, the surface of the heated body has a relative speed with respect to the second surface of the web. By the introduction of a relative speed an improved mechanical spreading action can be arrived at. This is even more so when the heated body is stationary.

In yet a further embodiment, the heated body is a stationary plate having a curvature in the transporting direction of the web. With respect to a heating drum as known from EP1598476, a plate has the advantage that the total heat capacity of the heated body is much lower. A drum or roller inherently has a larger volume that has to be heated and kept at its working temperature. In practice, small diameter drums are no option since then the contact length with the product to be heated is too short to obtain sufficient melting of the polymer without burning it. Also, even if it would be possible use a small diameter drum and force the product to travel along 90% of its circumference to provide for sufficient contact length, the primary backing sheet would be mechanically deteriorated by being forced to travel in contact with the drum along its small radius. Although a large heat capacity is advantageous for maintaining a stable working temperature, it is very disadvantageous for a quick start up or adaptation of the heating process. A heating plate offers the advantage of a relatively small heat capacity, which allows for more freedom in operating the manufacturing process. With respect to a blade as known from WO 2012/076348, a plate has the advantage of being better to maintain at a predetermined temperature, especially at high process speeds. The edge of a blade will simply cool down too much when heat is being extracted at a high travelling speed of the product. Only by choosing a material that is able to conduct heat extremely good, and by overheating the blade at its other end, it might be possible to obtain a sufficient high heat flow towards the edge of the blade. Such a process however is not very stable and difficult to control.

In another embodiment the polymer material is comprised in the yarns and/or the woven web. Although it is possible, as disclosed in EP1598476 to use a separately dosed polymer material to be used in forming the binding layer, it it easier to simply use the polymer material as present in the yarns and/or web material as the material to be heated and form the binding layer. By simply choosing a yarn material that can be melted and spread to form a binding layer (which layer does not need to be a homogenous thin layer, but may be for example comprised of discontinuous binding "spots" at each yarn, or bundle of yarns), for which purpose many regular polymer yarn materials will fit, no additional polymer needs to be added in a separate process step which makes the process simpler. The web can also be used to provide the required polymer material to provide the binding layer. For example, by covering the back surface of the primary carrier web with a porous layer of thin thermoplastic fibres (e.g. by laying a sheet of such a porous layer on the back surface, or by in situ constituting such a porous layer on the back surface) it was found that a very durable bond between the yarns and the primary backing can be obtained. Most probably this is due to the fact that the thermoplastic fibres in the layer, after at least partly melting and subsequent cooling (to re-harden the melted material) forms an additional locking means in the form of a (semi) continuous layer that grabs around the ends of the (melted) yarns.

In another embodiment downstream of the processing station the web is transported over a second bowed roller. This embodiment is advantageous in that the processed web is adequately guided and straightened for further processing, which processing may be as simple as winding on a roller after sufficient cool down. Also, if the second bowed roller is positioned within 2 meters, preferably within 1 meter, more preferably within 0.5 meters after the processing station, there is an expected positive effect on the configuration of the web at the processing station itself. In yet another embodiment the first and/or second bowed roller have an adjustable arc. In this embodiment the bow of the axle can be adjusted to arrive at an adequate balance between guidance of the web, prevention of distortion of the woven web and a homogenous binding strength of the yarns, independent of the type of woven web (whether woven from fibre, tape, low-melting polymer, high-melting polymer, type of weave etc.). The adjustment can be arrived at by extending the (net) length over which the roller axle extends, thereby lowering the arc. Easier to implement is an embodiment wherein the length and arc of the roller as such are fixed, but wherein the spatial configuration of the bowed roller is adjustable by rotating the bowed-roller set-up over the imaginary axle that extends between the ends points of the roller. For example, by rotating the bowed roller from a position wherein the arc is upright, over an angle of 90° to a position wherein the arc extends in horizontal direction, the actual tension applied to the web is altered from very high to very low.

In still another embodiment the primary carrier sheet is woven from polymer tape. This type of woven sheet is very inexpensive to produce but also, is mechanically very unstable. Therefore, it is difficult to guide this type of primary carrier through a process without distorting the consistency of the web. Surprisingly, using the current set-up of having a bowed roller within a short transport distance upstream of the processing station wherein the binding layer is provided, a web woven from polymer tape can be used to arrive at a good carpet product.

The invention will now be further explained based on the following figures and examples. EXAMPLES

Figure 1 schematically shows a cross section of a textile product manufactured according to the invention.

Figure 2 schematically shows details of a textile manufacturing process according to the invention.

Example 1 example describes two carpet products which can be made using a process according to the invention. Figure 1

Figure 1 is a schematic representation of respective layers of a laminated textile product 1 manufactured according to the invention, in this case a carpet tile. The tile comprises a primary carrier sheet 2, the so called primary backing, which is a woven polyester backing. The polyester yarns 5 extend from the first surface 3 of this first sheet and are sealed to the second surface 4 of the sheet using the yarn melting method as described with reference to figure 2. The weight of this primary sheet is typically about 400-700 g per m² (including tufted yarns). In order to provide sufficient mechanical stability for use as an end product such as a carpet tile, the product 1 comprises a primary backing sheet 6, in this case a polyester needle felt backing. The weight of this second sheet is typically about 500-1000 g/m². In between the first and second backing is an optional resilient layer 10 (which could for example be a polyester expansion fleece having a weight of 330 g/m², obtainable from TWE, Emsdetten, Germany as Abstandsvliesstof). The three layers (first and second backing and intermediate layer) are laminated together using a glue, which may be a polyester hot melt glue as obtainable from DSM, Geleen, the Netherlands, applied as layers 1 1 and 12 at a weight of about 300 g/m².

Figure 2

Figure 2 schematically shows details of a textile manufacturing process according to the invention. In particular, figure 2 shows the process step wherein the binding layer is created for fastening the yarns to the web (the so called fibre-binding step). In the configuration shown in Figure 2 a rigid curved heating plate 500 is present. In this embodiment the plate is an aluminium plate having a radius of 0.37 meter, a length of 40 cm (in the process direction) and a thickness of 1 cm. The plate is provided with two sided heating by having external canals 501 , 501 ', 502 and 502', which feed a hot oil of 295°C in opposite directions. The oil is heated in heating bath 503, pumped to the plate and returned to the heating bath 503 after circulation through the volume of the plate (conduits external of the plate towards and from the heating bath are not shown in figure 2). The heated outer circumferential (convex) surface 510 of this plate 500 is brought in contact with a textile product to be processed, of which product the first sheet 2 (the so- called primary carrier), which in this case is a woven sheet provided with pile yarns applied via a tufting process, is shown. The first sheet is transported face up such that the pile is directed away from the heating plate 500. In operation, the heating plate is stationary and the product is transported relative to the plate in a direction from entrance 301 to sensor 300.

At about 0.5 meters before the entrance 301 of the heating process a bowed roller 303 is present to guide the sheet (in the form of a continuous web with a width of about 4 meters and a length of about 200 meters) towards the curved heating plate 500. In this particular embodiment the bowed roller is a steel roller provided with a rubber sleeve. The diameter of the roller is 190 mm, and its length is 4400 mm. The height of the arc of the roller is 60 mm. The roller can be spatially configured between two positions. The first one wherein that the arc extends in vertical direction (at 90° with respect to the web) and the second one wherein the arc extends in horizontal direction (at 0° with respect to the web). During the fibre-binding process the spatial configuration is such that the arc extends at an angle between 0 and 90°, typically between 20 and 90°, with respect to the running web. The sheet 2 enters the heating process at position 301. The height of the entrance depends on the vertical position of bowed roller 303. The roller is displaceable in vertical direction, indicated by double arrow A. This way, the contact length between the plate and the sheet can be varied. At the lowermost position of the roller 303, the contact length is at maximum (i.e. the complete length of the curved plate 500), at the highest position of the roller 303, the contact length is at minimum (in this case about one third of the length of the plate 500). At the end of the plate, the sheet 2 is guided by roller 302 towards a calendering nip that consists of cold stationary bar 305 and roller 306. The temperature of the cold bar and roller (which are controlled via CPU 320) is such that the product, in the nip, will have a temperature between the Tg (glass transition temperature) and Tm (melting temperature) of the polymer material in the binding layer. This nip can be used to effect an additional calendering action on the textile product, or actually, the back of the textile product. The position of the bowed roller 303, the heat of the heating bath 503 and the pressure and temperature of the calendering nip (305, 306) are controlled with CPU (central processing unit) 320. This unit controls these various parts using i.a. surface roughness data of the back of the textile product as measured by sensor 300. For this, the sensor is connected to the CPU via line 315. The bath 503, the vertical positioning means of the bowed roller 303 and the calendering nip (305, 306) are connected to the CPU via lines 316, 317 and 318 respectively.

The (intermediate) textile product to be processed with the above described

configuration may consist of a woven primary sheet provided with a cut pile of polyester yarns, tufted into the sheet. The yarns typically have a melting temperature of about 260-280°C. This product is processed using a temperature of the heating element 500 of 285-300°C in order to heat the product. The product, having a width of about 4 meters, corresponding to a width of 4.20 meters of the curved heating element 500, is supplied at a speed of 2 metres per minute or higher. Due to the curved constitution, the pressure with which the product is pulled onto the heating element is about is 1.25

Newton per square centimeter. This way, the loops of the yarns at the second surface of the primary carrier sheet are partly molten to provide a binding material and

mechanically spread over the second surface to form a semi-continuous layer of molten material that locks the yarns into the first sheet. Depending i.a. on the temperature of the heating elements, the vertical position of the bowed roller 303 and the use of the calendering nip, this will result in a second surface having a more or less smoothed surface with some noticeable surface texture.

Downstream (distal) of the curved heating plate 500, at a section where the molten material of the binding layer will be sufficiently solidified, directed to the second surface of the product 2, is an optical surface roughness measurement sensor 300. With this sensor the 2D surface roughness of the second surface can be measured and data corresponding to this surface roughness are send to CPU 320 via line 315. In this CPU, the actual surface roughness data are compared to predetermined values. If the data match these values, no adaptation of the manufacturing process will follow. If however the data indicate that the roughness is either too small (surface too smooth) or too large (surface too rough), the contact length between the product and the plate may be adapted. Also the heating temperatures of the oil may be adjusted by adapting the flow rate of the oil through the plate, or the action of the calendering nip may be adapted in order for a next section of product to meet the predetermined surface roughness data. Further downstream is a second bowed roller 303' to further guide the processed web, for example to a laminating station.

Example 1

This example describes two carpet products (product A and product B) which can be made using a process according to the invention, in particular using the machine set-up as described in conjunction with figure 2. Both products are based on a primary backing made from woven polymer tape. In this backing the warp yarns, which are made of a 1 .0 mm wide polyester tape of 42 Tex, are woven at 1 12 yarns per 10 cm. The weft yarns, made of a 2.0 mm wide polyester tape of 86 Tex, are woven at 59 yarns per 10 cm. This results in a woven sheet having a very low weight of about 100 g/m², relatively inexpensive to produce, and which is stable enough for mechanical handling and guidance over rollers. However, since the warp and weft tapes are very flat and smooth, local strain or tension can lead to significant distortion of the weave pattern and thus, of a pattern of yarns stitched therein. Both carpet products having polyamide yarns tufted therein. These yarns from loops at the back of the primary backing and a pile on the front of the backing. The second one of the carpet products (product B) has an additional layer of meltable polymer fibres at the back of the primary backing. For this, before the polyamide yarns are stitched into the backing, the back surface of this backing is covered with a thin felted fibrous layer. This layer is made by covering the back surface of the primary backing with 5 dTex fibres having a length of about 50 mm, 70% of the fibres being of polyamide (T_m about 220°C) and 30% of the fibres being of a low melting polyester (T_m about 230°C). The fibres are provided in an amount of about 45 g/m². This layer is needle-felted to the primary backing, thereby forming in fact a dual layer primary backing.

Both intermediate products are subjected to the fibre-binding process as described with reference to figure 2. The heat of the plate, together with the fact that the back of the primary backing is pressed against the plate while being fed there along, leads to the (at least partial) melting of the loops of the yarns at the back, and thus to the provision of a binding layer of molten polymer material. For product B, the at least partial melting of the additional felted layer porous layer, leads to additional material available for this binding layer. The molten material is spread and smoothed out over the back of the primary backing due to the fact that the heated plate is stationary with respect to the web that is being transported over the plate. This ultimately results in a binding layer that is able to firmly secure the yarns at the back of the primary backing.

The resulting carpet products have a good and regular face side, showing no distortions visible with the naked human eye. The patterns of the yarns appear to be equal to the patterns as provided in the original tufting process. The textile products were subjected to a tuft bind test according to ASTM D1335-12 ("Standard Test Method for Tuft Bind of Pile Yarn Floor Coverings") in order to establish the actual tuft bind strength, and also whether or not the binding strength was homogenous over the surface of the carpet products. The resulting tuft bind was 24,9 N for the textile product incorporating the additional felted layer and 17,9 N for the textile product without this layer. The tuft bind was even across the surface of the carpet products.

Claims

A method to manufacture a textile product comprising a primary carrier sheet and yarns that form a pile thereon, the method comprising:

providing a woven web as the primary carrier sheet,

stitching the yarns through the woven web to form the pile on a first surface of the web and loops of the yarns at a second surface of the web, transporting the web along a processing station, at which station a binding layer is provided at the second surface of the web to fasten the yarns to the web,

wherein the method comprises transporting the sheet upstream of the processing station over a first bowed roller, wherein the transport distance between the bowed roller and the centre of the processing station is less than 2 meters.

A method according to claim 1 , characterised in that the transport distance between the first bowed roller and the centre of the processing station is less than 1 meter.

A method according to claim 2, characterised in that the transport distance between the first bowed roller and the centre of the processing station is between 0.1 and 0.5 meter.

A method according to any of the preceding claims, characterised in that at the processing station, a polymer material is present at the second surface of the web and heat is provided to melt the polymer material to provide the binding layer.

A method according to claim 4, characterised in that the heat is provided by contacting a surface of a heated body with the second surface of the web.

A method according to claim 5, characterised in that the surface of the heated body has a relative speed with respect to the second surface of the web.

A method according to claim 6, characterised in that the heated body is a stationary plate having a curvature in the transporting direction of the web.

A method according to any of the claims 4 to 7, characterised in that the polymer material is comprised in the yarns and/or the woven web.

A method according to any of the preceding claims, characterised in that downstream of the processing station the web is transported over a second bowed roller.

A method according to any of the preceding claims, characterised in that the first and/or second bowed roller have an adjustable arc.

A method according to any of the preceding claims, characterised in that the primary carrier sheet is woven from polymer tape.

Use of a textile product obtainable according to any of the claims 1 to 1 1 to cover a surface of a building or any other artificial or natural construction.

A device for use in manufacturing a textile product comprising a primary carrier sheet and yarns that form a pile thereon, the device comprising: an upstream entrance for accepting the primary carrier sheet in the form of a web with the yarns stitched therethrough to form the pile on a first surface of the web and loops of the yarns at a second surface of the web, transporting means for transporting the web along a processing station, at which station binding means are present to provide a binding layer at the second surface of the web to fasten the yarns to the web, characterised in that the transporting means upstream of the processing station comprises a bowed roller for guiding the sheet, wherein the transport distance between the bowed roller and the centre of the processing station is less than 2 meters.