EP3371366B1

EP3371366B1 - A method to manufacture a textile product, a use thereof, the product itself, and a device for applying the method

Info

Publication number: EP3371366B1
Application number: EP16793825.7A
Authority: EP
Inventors: Chris Reutelingsperger
Original assignee: DSM IP Assets BV
Current assignee: Covestro Netherlands BV
Priority date: 2015-11-05
Filing date: 2016-11-04
Publication date: 2019-12-25
Anticipated expiration: 2036-11-04
Also published as: AU2016348719A1; DK3371366T3; US20180320310A1; MX2018005521A; WO2017077043A1; KR20180079416A; BR112018009021A8; EP3371366A1; JP2019501680A; BR112018009021A2; CN108350649A

Description

GENERAL FIELD OF THE INVENTION

The present invention pertains to a method to manufacture a textile product, in particular a carpet product such as broadloom carpet, carpet tiles, mats and rugs, comprising a first sheet having polyamide yarns fastened to this sheet to form a pile thereon, the method comprising providing the sheet, stitching the polyamide yarns through the sheet to form the pile on a first surface of the sheet, the pile extending for a predetermined length from this first surface, and to form loops of the yarns at a second surface of the sheet, and fastening the yarns to the sheet by creating a layer of fused material on the second surface of the sheet using heat. The invention also pertains to a method to use a textile product obtained with the new method, the textile product itself and a device for applying the said method.

BACKGROUND ART

Traditionally textile products such as carpet products are made by firstly forming an intermediate material of yarns being stitched, typically tufted or woven, into a primary backing (the first sheet), and optionally cut, to form a pile on top of the first surface this primary backing, and loops of the yarns on the second surface (the back side) of this backing. In such an intermediate layer, the yarns can be pulled out of the backing by using a light pulling force, for example by pulling on a yarn by hand. In order to create a textile product wherein the yarns are adequately mechanically anchored in the primary backing, a layer of fused material may be created on the back surface of the primary backing. The fused layer may be a simple molten and thereafter solidified thermoplastic material (such as hot melt adhesive), a cured layer of resin (such as latex), or a hardened layer of a rubbery substance (such as a bituminous material) etc. By creating such a fused layer, the loops of the yarns are anchored to the primary backing and therewith adequately mechanically attached to withstand normal mechanical loads. In order to create the fused layer, the intermediate product with the starting material for the fused layer is normally transported through a long oven (50-100 meters), typically at 180-200°C in order to create an adequate fused layer.
EP 1598476 (Klieverik Heli ) describes a method in which no latex or bituminous layer is used to anchor the yarns to the primary backing. The layer of molten material is created by feeding the backing (yarn upwards) along a heated roller surface while its underside is pressed against the roller so the yarns will at least partly melt to form a layer of fused material, the layer optionally incorporating an adhesive applied in the form of a powder before the back side of the primary backing is processed using the heated roller. In the application it is stated that after cooling the yarns are firmly anchored to each other and the backing without the need for a latex polymer. One embodiment teaches that 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 smear 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 actually directly fuse by heat alone. This method provides the advantage that the intermediate backing can be easily recycled since the yarns and primary backing can be made from the same polymer. There is no incompatible latex or bituminous material penetrated into the fibre piles.
WO 2012/076348 (Niaga ) describes a method for manufacturing textile products that even improves the anchor strength of the yarn with respect to the method as described in EP 1598476 . In this method, when the primary backing is pressed against the heated surface, a relative speed between the primary backing and the heated surface is introduced. Due to this relative speed, an additional mechanical force is provided on the molten material in the machine direction (i.e. the direction of transport of the primary backing). This force spreads the material of the yarn whilst it is still molten resulting in a more homogenous layer of fused material and thus a stronger overall bond between the primary backing and the yarns. Though in theory in many cases an additional secondary support layer may no longer be necessary, this document does teach that such a support layer may still be useful, especially if it comprises a reactive adhesive relying on thermally reversible reactions between reactive molecules present at the interface between the textile product and the carrier material.
A research disclosure (RD591084) was also published anonymously on 25 June 2013 describing certain methods for manufacturing carpets using a method as described here above in combination with polyester hot melt glues.
For high end applications polyamide yarns are often used for the pile of textile products. Polyamide (PA or nylon) are very resistant to wear and abrasion, have good mechanical properties even at elevated temperatures, and have good chemical resistance. However, polyamide has a very low stain resistance whereas polyester (used for yarns in non-high end applications) generally has a good stain resistance.

OBJECT OF THE INVENTION

It is an object of the invention to provide for a method to manufacture a textile product using polyamide yarns, wherein the polyamide yarns have an improved staining resistance.

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 during creating of the layer of fused material, at least the distal half of the length of the pile is maintained at a temperature at least 70°C below the melting temperature of the polyamide.
Without being bound to theory, this invention was based on a couple of recognitions. First of all, it was recognised that in all polyamide yarns, the polyamide material is at least to some part amorphous. As is commonly known, the amorphous part of polyamide can be oriented or non-oriented (see for example Appl Spectrosc. 2005 Jul;59(7):897-903).The number of amino and acid groups available for stains to attach to, is believed to be higher in the non-oriented amorphous zones. Heat setting generally increases the percentage of this stain sensitive non-oriented amorphous part. In the traditional manufacturing technologies, heat is used to create the fused layer, typically well above 180°C, whereby due to a heat flux to the yarns, even the distal (top) half part of the pile is heated to temperatures such that this heat setting typically occurs. This means that the pile yarns have a decreased resistance towards staining when compared with the starting yarn material. Applicants found that by keeping the temperature of at least the distal half of the length of the pile (when a pile has a mixed height, the distal half of the length of the highest pile is relevant) at a temperature of at least 70°C, preferably at least 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99°C or more, below the melting temperature of the polyamide during a period wherein the layer of fused material is created, heat setting as described here above can be prevented or at least significantly reduced, such that at least this top half of the pile has a improved stain resistance when compared to traditionally made textile products, in particular carpet products such as broadloom carpet, carpet tiles, mats (such as entrance mats and car mats) and rugs.
The invention is also directed to the use of a textile product obtainable according to the invention to cover a surface of a building or any other artificial or natural construction. The invention is also directed to a device for use in manufacturing a textile product comprising a first sheet having polyamide yarns fastened to this sheet to form a pile thereon, the yarns being stitched through the sheet to form the pile on a first surface of the sheet, the pile extending for a predetermined length from this first surface, and loops of the yarns at a second surface of the sheet, wherein the device comprises respectively a heating means for heating the second surface of the sheet, a means for creating a mass of fused material on the second surface of the sheet, and cooling means for cooling at least the distal half of the length of the pile to a temperature at least 70°C, preferably at least 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99°C or more, below the melting temperature of the polyamide during creating the mass of fused material.
The invention is also directed to a textile product comprising a sheet having a top surface and a bottom surface, the textile product having polyamide yarns stitched through this sheet to form a pile on the surface of the sheet, the pile extending for a predetermined length from this first surface, the yarns being fastened to the bottom surface of the sheet by forming a layer of fused polyamide material on this bottom surface, the yarns in the pile have a decreased amorphous content with respect to yarns of the same polyamide annealed at a temperature of about 43°C (i.e. between 40 and 45°C) below the melting temperature of the polyamide for 1 hour.

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. Laminated 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).
Polyamide yarns are yarns containing at least 10% of polyamide material, preferably at least 20, 30, 40, 50, 60, 70, 80, 85, 90, 95 up to 100% of polyamide.
Polyamide (PA or nylon) is the generic name for all long-chain fiber-forming polyamides with recurring amide groups. Depending on the type of PA, melting temperatures may range from 190 to 350°C, typically between 220 and 260° for polyamides used for making yarns for textile materials such as carpet (mainly PA6 and PA66). PA is always at least partly amorphous (either completely amorphous or semi-crystalline). PA6 (nylon 6), also called polycaprolactam, is a polymer developed by Paul Schlack to reproduce the properties of PA66 (nylon 6,6). Like PA66, it is a semicrystalline polyamide. Unlike most other nylons, PA6 is not a condensation polymer, but instead is formed by ring-opening polymerization. It's melting temperature is around 220°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 product.
A sheet is a substantially two dimensional mass or material, i.e. 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 layer is a thickness of material, laid on or spread over a surface. A layer may be inhomogeneous with respect to thickness and may be discontinuous in the sense that it may have holes in it.
A laminate is a structure comprising multiple stacked layers mechanically connected to each other.
Resilient means to be able to deform and automatically return to the original configuration.
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.
Fibrous means consisting basically out of fibres. The term "basically" in this respect means that the basic mechanical constitution is arranged out of fibres: the fibres may however be impregnated or otherwise treated or combined with a non-fibrous material such that the end material also comprises other constituents than fibres. Typical fibrous sheets are woven and non-woven textile products, or combinations thereof.

EMBODIMENTS OF THE INVENTION

In a first embodiment of the method according to the invention the distal half of the length of the pile is maintained at a temperature at least 100°C below the melting temperature of the polyamide. It was found that although 70°C is already well below the melting temperature, and thus, heat setting was expected to be not or hardly present, the method could be improved by maintaining the temperature of the yarns at least 100°C below the melting temperature of the polyamide. Apparently, heat setting still occurs to some relevant extent even in the range of 70-100 degrees celsius below the melting temperature of the polyamide. It is found that the heat setting can be prevented substantially completely when the temperature is maintained at 125 - 150°C below the melting temperature of the polyamide.
In a second embodiment the at least distal half of the length of the pile is maintained at the temperature below the melting temperature of the polyamide using cooling means. Such cooling means may for example be a chilled roller contacted with the pile side of the first sheet, or a blower for blowing cold gas over this pile side, while the back of the sheet is heated in order to form the fused layer. However, any other passive or active means for maintaining the temperature of the pile at a temperature as defined according to the invention may be used instead.
In another embodiment, for fastening the yarns to the sheet, the second surface of the sheet is contacted with a surface of a hot body to at least partly melt the loops of the yarns to create the mass of fused material. In this embodiment the layer of fused layer to anchor the yarns is created using methods as known for example from EP 1598476 , WO 2014/198731 , US 2002/132084 , US 5556684 , US 2012/0219751 , EP 2172589 and WO 2012/076348 . To applicant's surprise, even when using such a method wherein a hot surface is used to actually melt the polyamide in the loops of the yarns, the temperature of the pile (at least the distal half of the pile) can be kept below a temperature where heat setting significantly influences the stain resistance of the polyamide. This can be done using either active cooling means, or depending mainly on the height of the pile, the density of pile, the exact materials used, and the required time of contact with heated surface to create the layer of fused material, by simply relying on the heat transport through the pile (by conduction, radiation and/or convection) being too slow to heat up the top half of pile above the critical temperature regarding inducing a staining problem.
In a further embodiment the surface of the hot body has a relative speed (and thus moves at a relative speed greater than 0 m/s) with respect to the second surface of the first sheet. As such, the use of a hot body that has a relative speed with respect to the second surface during the melting process of the yarns is known from WO 2012/076348 . It now appears that this feature is ideally suitable for use in a method wherein the yarns are polyamide yarns, aiming at an increased stain resistance of the pile. In a further embodiment the surface of the hot body is stationary, whereas the first sheet is transported along the hot body.
In an embodiment wherein the textile product is a laminate of the first sheet and a second sheet, after the second surface of the first sheet has been processed according to any of the embodiments as described supra, an adhesive is applied to this second surface to which adhesive the second sheet is adhered. In a further embodiment the adhesive is a hot melt adhesive, for example a hot melt adhesive that comprises at least 50% by weight of a polymer chosen from the group consisting of polyurethane, polycarbonate, polyester, polyamide, poly(ester-amide), polyolefine, mixtures thereof and/or copolymers thereof.
In a further embodiment of the laminated textile product, an intermediate layer is provided between the first sheet and the second sheet wherein the intermediate layer is resilient to allow local deformation of this layer along the second surface of the first sheet or along the surface of the second sheet adjacent to the intermediate layer. This embodiment appears to be suitable to prevent or at least mitigate a common problem of laminated textile products: internal strain in the laminate, in particular due to the influence of moist, temperature or other environmental variables. Internal strain on its turn may lead to various problems. With carpet tiles for example, internal strain may lead to the problem of curl: the edges or corners of the tiles tend to curl up. Curling of edges or corners is a problem since the edges in general to not coincide with an edge of the surface to be covered, and thus, the curled up edges or corners may lead to irregularities in center areas of the covered surface. With broadloom carpet, internal strain may lead to deformation such that interstices are formed at the joint of two sections of carpet. Also, for any laminated textile product, internal strain may lead to bulges and local excessive wear. An important reason for the occurrence of internal strain is that the laminate inherently comprises different layers (note: the term "layer" or "sheet" does not exclude that the layer or sheet is actually constituted out different sublayers) that need to provide very different properties to the textile product: the first sheet (the primary backing) needs to stably bear the pile yarns. The second sheet (the secondary backing) in general provides dimensional stability to the textile product. For this reason, the structure of the different layers is inherently different. And thus, even when for example the first and second sheet are made of the same material, the occurrence of internal strain due to different deformations by the action of moist and temperature, is inherently present. The problem is even increased when different materials are being used for constituting the sheets, in particular when these materials per se expand and contract differently due to moist and or temperature. In the present invention, the pile yarns are polyamide yarns, whereas the polymer used for the primary and secondary backing is mostly polyester. These polymers have totally different deformation characteristics due to moist and temperature. It has now been surprisingly found that this problem can be solved or at least mitigated when using a resilient layer as described here above in between the first and second sheet. Without being bound to theory, it is believed that due to the resilient properties as defined here above, it is provided that each of the sheets may expand or contract ("deform") in the horizontal direction independently of an expansion or contraction of the other sheet, and thus, that no (or only low) internal strain (which may lead to curl or other deformation) may arise. This can be understood as follows: due to the resiliency of the intermediate layer which allows local deformation of the material in this layer along the surface of at least one sheet, the horizontal deformation of (one of) the sheet(s) may now be locally absorbed by the intermediate layer, without mechanical forces being transferred directly from the first sheet to the second sheet or vice versa.
In yet another embodiment the intermediate layer is a fibrous layer. Fibres can be easily assembled to form a stable layer, and still provide for the option of local deformation. For example when fibres are entangled but not mechanically connected at the sites were fibres cross, deformation may stay locally, while the layer as a whole has significant mechanical stability.
In still another embodiment the intermediate layer is a non woven layer. Non woven layers are easy to assemble, even when using very short fibres and are therefore economically attractive. While short fibres may prevent deformation to be easy transferred over distances considerably longer than the fibres themselves, long fibres, due to the non-woven arrangement (for example meandering like a river) may also be perfectly capable of allowing local deformation and not transferring forces to the neighbouring areas.
In a further embodiment the intermediate layer is a knitted layer. A knitted layer, although the fibres are in essence endless, appears to be perfectly suitable to allow only local deformation. Like a tubular knitted sock that fits every curve of a foot, a knitted layer can easily deform locally without transferring forces to neighboring areas. A knitted layer for use in the present invention is for example Caliweb®, obtainable from TWE, Emsdetten, Germany.

EXAMPLES

Figure 1 schematically shows a cross section of a textile product manufactured according to the invention
Figure 2 schematically shows a configuration for applying a yarn melting process
Figure 3 schematically shows details of an active cooling means
Figure 4 schematically represents a laminating configuration
Example 1 provides process parameters for a method according to the invention
Example 2 is an example of a specific laminated textile product according to the invention
Example 3 provides a method to establish dirt retaining properties of carpet.
Example 4 provides a method to determine whether or not the textile product is a product according to the invention.

Figure 1
Figure 1 is a schematic representation of respective layers of an embodiment of a laminated textile product manufactured according to the invention, in this case a carpet tile. The tile comprises a first sheet 2, the so called primary backing, which may be a tufted nonwoven sealed polyester backing. The polyamide 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 first sheet is typically about 500-800 g per m². In order to provide mechanical stability, the tile 1 comprises a second sheet 6, in this case a polyester needle felt backing. The weight of this second sheet is typically about 700-900 g/m². In between the first and second sheet 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 sheet 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 11 and 12 at a weight of about 300 g/m².
Figure 2
Figure 2 which schematically represents a configuration for applying a yarn melting process (also called a fibre-binding process) for use in the present invention. In the configuration shown in Figure 2 a first heating block 500 and a second heating block 501 are present, in order to heat the heating elements, also denoted as heating blades or heating bodies, 505 and 506 respectively. These heating elements have a working surface 515 and 516 respectively, which surfaces are brought in contact with a product to be processed, typically a primary carrier to which yarns are applied via a stitching process such as tufting. The working surfaces both have a working width of 18 mm, and the intermediate distance is 26 mm. The back surface of the product is brought in contact with the working surfaces of the heating elements. In order to be able and apply adequate pressure for the product to be processed, an actively cooled Teflon support 520 is present which is used to counteract a pushing force applied to the heating elements and at the same time cool the polyamide pile yarns. In operation, the heating elements are moved relatively to the product as indicated by arrow X. Typically, the heating elements are stationary and the product is forced to travel between the working surfaces and the Teflon support in a direction indicated with X.
The (intermediate) textile product to be processed with the above described configuration (the product itself is not shown in Figure 2) consists of a primary sheet provided with a cut pile of polyamide yarns, tufted into the sheet. The yarns consist almost 100% of PA6 and typically have a melting temperature of about 220°C. This product is processed using a temperature of the first heating element of 180-200°C, in order to pre-heat the product. The second heating element is kept at a temperature about 15°C above the melting temperature of the polyamide yarns. To keep the temperatures at the required level, the heating blocks and heating elements are provided with layers of insulating material 510, 511, 512 and 513 respectively. The product is supplied at a speed of 12 mm per second (0.72 metre per minute) or higher, and the pressure applied with the heating elements is about 1.35 Newton per square centimetre. This way, the PA yarns are melted and form a layer of molten material on the second surface of the primary backing. By using the cooled Teflon plate, the temperature of the pile, at least the top half of this pile is kept at about 95°C during this melting process. After the melting process, the molten layer is cooled down and forms a layer of fused PA material.
Downstream of the heating blocks, at both sides of the transport path 200 of the intermediate textile product to be processed, is a further active cooling means 300. In this embodiment, the means 300 comprise inverted domes 301 and 302. Through these domes, cold cooling air can be blown towards the textile product, in order to actively cool the heated surface of the textile product.
Figure 3
Figure 3 schematically shows details of another embodiment of the invention. In this embodiment, the heating bodies 505 and 506 are arranged around a circular support 520' which is actively cooled to a temperature of about 90°C. The intermediate textile product 2 is transported with its second surface 4 towards the heating bodies, while the product 2 is lying with its first surface on the rotating support drum 520'. At the downstream side of the drum 520', the intermediate product is transported along transport path 200 and encounters active cooling means 300'. In this embodiment, the cooling means is a Teflon@ coated aluminum stationary massive beam 305 having a thickness of 20 mm, kept at a temperature below the glass transition temperature of the polyester yarns, typically below 120°C. The beam has a length L₁ of 80 mm in the transport direction, and is situated at a distance L₂ of 76 mm from heating body 505. The beam is pressed against the second surface 4 of the textile product 2 to provide for an additional calendaring action. This way, the process may lead to a product having a smooth and glossy back surface at the sites where the stitched yarns extend from this back surface.
Figure 4
Figure 4 schematically represents a laminating configuration for applying a second sheet, in this case a dimensionally stable secondary backing sheet, to the back of the first sheet that is produced with a method as described in conjunction with Figure 2. In this embodiment the term target sheet denotes either the separate resilient layer and second sheet applied one after the other in that order, or the combined laminate of them both applied together to the first sheet. Both the second sheet and the resilient layer may be of polyester. In this figure a first roller 600 is depicted on to which roller is wound a 2 metre wide web of the said (pre-fabricated) product made according to the method described in conjunction with Figure 2. The product is unwound from the roller 600 to have its back-side 217 to come into contact with a second roller 601. This roller is provided to apply a layer of hot melt adhesive (HMA) 219 to the back side 217. For this, a bulk amount of HMA 219 is present and heated between the rollers 601 and 602. The thickness of this layer can be adjusted by adjusting the gap between these two rollers. Downstream of the site of HMA application is the target sheet 215, which sheet is unwound from roller 603. This sheet is pressed against the hot and tacky adhesive and cooled in the unit 700. This unit consists of two belts 701 and 702 which on the one hand press the target sheet 215 against the primary product, and on the other hand cools down the adhesive to below its solidification temperature. The resulting end product 201 (corresponding to textile product 1 of Figure 1) is thereafter wound on roller 604. In an alternative embodiment the fibre-binding process as described in relation with Figure 2 and the lamination process take place in line. In that case, the fibre-binding set-up as shown in Figure 2 could be placed between roller 600 and roller 601. In this embodiment the applied HMA is the polyester of Example D as described in the Research Disclosure RD591084 as mentioned herein before. A suitable temperature of the roller 601 at the site where this HMA is applied to the back-side of the primary backing is 140°C. By having a gap of 2 mm, the HMA, at a web speed of 2m/min, roller 602 not revolving and roller 601 having a circumferential speed of ± 1.6 m/min, will be applied with a thickness of about 500g/m². This is adequate to glue the target sheet 215 to the primary backing (i.e. the first sheet).
The hot melt adhesive may be optionally provided as a layer having a thickness of less than 1 mm, usefully less than 0.5 mm, more usefully from 0.2 to 0.4 mm. Whereas in the prior art carpets on the market, the hot melt layer typically has a thickness well above 1 mm, applicant found that when reducing the thickness of this layer to 1 mm or below an adequate adhesion can still be obtained. Therefore, the adhesive layer present in textile products of the present invention may have preferred mean thickness of from 50 microns to 1 mm, more preferably from 0.1 mm to 0.8 mm, most preferably from 0.2 mm to 0.4 mm. The amount of HMA used to form the adhesive layer in textile products of the present invention may be from 0.01 to 1000 g/m² of HMA per area of the adhesive layer. In another embodiment the HMA may be applied in an amount of from 0.05 to 800 g/m². In a still yet other embodiment HMA may be applied in an amount from 0.1 to 600 g/m².

Example 1

Example 1 provides process parameters for a method according to the invention. In this example, the process parameters for a set up as depicted in figure 3 are given. The textile product is heated with heating body 505 to a temperate of 235°C. At the position where the product leaves the nip between heating element 505 and roller 520', the temperature of the top of the pile (as measured using an IR camera) is about 95°C (about 125°C below the melting point of PA). When the product arrives at the cooling beam, its temperature at the side bearing the layer of fused material is still around 160°C. The beam actively cools this hot surface very quickly, due to the intensive contact, to a temperature of about 100°C at the end of the length L₁ of the beam. This temperature is reached within 10 seconds after the second surface is heated with heating body 505.

Example 2

Example 2 is an example of a specific laminated textile product according to the invention. Reference numbers refer to parts corresponding to the textile product as shown in Figure 1. The textile product of this example comprises a first sheet 2 (the primary backing), which is a 100% polyester non-woven having a weight of 120 g/m² obtained from Freudenberg Vliesstoffe SE & Co. KG Neuenburg, Germany. This primary backing is tufted with a cut pile of 100% PA6 yarns (available from Aquafil (Cartersville, Georgia, USA). The polyamide yarns 5 extend from the first surface 3 of the primary backing and are sealed to the second surface 4 of the primary backing using the fibre binding method as described with reference to Figure 2. The total weight of this tufted sheet is about 700 g/m². In order to provide mechanical stability, the textile product comprises a secondary backing (second sheet 6), in this case a backing of a polyester needle felt backing fleece obtained as Qualitex Nadelvlies from TWE, Emsdetten, Germany. The weight of this second sheet is about 900 g/m². The layers are glued together using a polyester hot melt glue from DSM, Geleen, The Netherlands (available under the trade name Uralac®), applied at a weight of about 300 g/m² (which is the same amount as typically used for textile products having polyamide yarns tufted to the primary backing and processed with the same fibre binding method). The total weight of the carpet tile is thus about 1.9 kg/m². The laminated textile product appears to be very durable and resistant against delamination.

Example 3

A piece of carpet made in accordance with example 2 was tested regarding its properties to retain dirt (or, to let go dirt). In this method a piece of carpet having dimensions of 180 x 600 mm is firstly intensively contacted with dirt, by adding 15 grams of so called "VNTF" dirt (a standard type of dirt, a predetermined mixture of pigmented organic and inorganic solid materials, mineral oil, and quartz crystal sand, standardized by the Organisation of Dutch Carpet Producers; available from the TFI Institute in Aachen, Germany), and fixing the dirt in a Tetrapod machine (see Journal of the Textile Institute Transactions, Volume 56, ) during 800 rotations. After this, the carpet is cleaned in a standardised way using a machine as described in EP2198263 (titled "A method for testing the impact of a cleaning process on a property of a fabric, an apparatus for use in such a method, and use of said method or apparatus for labelling a fabric"), in particular with reference to figures 1, 2 and 3 of this patent application. In this case a vacuum cleaner was used to collect the dirt. The amount of collected dirt was measured by weighing with an accuracy of 0.0001 gram. The experiment was done four times with pieces of carpet made according to example 2. As a control, the same type of carpet was used for the control experiments, albeit that the control carpet was previously annealed for 10 minutes in an oven at 170°C. This annealing step corresponds to a (minimal) annealing step when a carpet is made using a traditional technique where the carpet as a whole is heated in an oven to fix the secondary backing. In each experiment both carpet types were treated in the same tetrapod machine, and both pieces of carpet were cleaned in the same machine. The results of the amounts of dirt released by the carpets are indicated in Table 1 below. Table 1 Amount of dirt extracted (grams)

Experiment PA carpet, heat annealed PA carpet of the invention

1 4.1014 6.0891

2 5.4162 6.6511

3 6.1916 6.6508

4 6.1331 7.0993
From this experiment it can be concluded that a PA carpet made according to the invention has better dirt release properties than traditional carpet and therefore can be qualified as a low stain carpet.

Example 4

Example 4 provides a method to determine whether or not the textile product is a product according to the invention. In this method the polyamide material which is the same as the material used for the yarns in the textile product is subjected to an annealing temperature well below 180°C. This temperature is chosen since it is a typical temperature for any conventional backing oven used to fuse a secondary backing to a textile material and is about 43°C below the melting temperature of a typical PA used for making carpet. The fact that the amorphous content of the material after 1 hour of annealing is below that of the same material annealed at 180°C, demonstrates that such a material processed according to the method of the invention will also lead to a product according to the invention.
Depicted in Table 2 are the results from the annealing experiment of PA6 material tycially used for yarns of carpet products. The material is presented as non-fiber bondend fibers, and heated for 1h at different temperatures as indicated. The lowest temperature is about 150 °C below the melting temperature of the polyamide. The middle-temperature is slightly over 70°C below the melting temperature. With a differential scanning calorimeter device, the Tg (glass transition temperature) and Tm (melting temperature) of the material is measured after the heat treatment. Table 2 Tg and Tm for PA6 material annealed at different temperatures.

Temperature [°C] Tg [°C] Tm [°C]

70 56.7 223.3

150 53.2 223.3

180 50.9 221.3
The measurements show that at 180°C (about 43°C below the melting temperature of the polyamide used), the Tg and Tm drop and thus that fibers are more amorphous, in line with theory. This means that the fibers, by staying at least 70°C below the melting temperature of the polyamide, remain higher in crystallinity.

Claims

A method to manufacture a textile product comprising a first sheet having polyamide yarns fastened to this sheet to form a pile thereon, the method comprising:
- providing the sheet,

- stitching the polyamide yarns through the sheet to form the pile on a first surface of the sheet, the pile extending for a predetermined length from this first surface, and to form loops of the yarns at a second surface of the sheet,

- fastening the yarns to the sheet by creating a layer of fused material on the second surface of the sheet using heat,
characterised in that during creating the layer of fused material, at least the distal half of the length of the pile is maintained at a temperature at least 70°C below the melting temperature of the polyamide.
A method according to claim 1, characterised in that the distal half of the length of the pile is maintained at a temperature at least 100°C below the melting temperature of the polyamide.
A method according to any of the preceding claims, characterised in that the at least distal half of the length of the pile is maintained at the temperature below the melting temperature of the polyamide using cooling means.
A method according to any of the preceding claims, characterised in that for fastening the yarns to the sheet, the second surface of the sheet is contacted with a surface of a hot body to at least partly melt the loops of the yarns to create the mass of molten material.
A method according to claim 4, characterised in that the surface of the hot body has a relative speed with respect to the second surface of the first sheet.
A method according to claim 5, characterised in that the surface of the hot body is stationary, whereas the first sheet is transported along the hot body.
A method according to any of the preceding claims, wherein the textile product is a laminate of the first sheet and a second sheet, characterised in that after the second surface of the first sheet has been processed according to any of the preceding claims, an adhesive is applied to this second surface to which adhesive the second sheet is adhered.
A method according to claim 7, characterised in that the adhesive is a hot melt adhesive.
A method according to claim 8, characterised in that the hot melt adhesive comprises at least 50% by weight of a polymer chosen from the group consisting of polyurethane, polycarbonate, polyester, polyamide, poly(ester-amide), polyolefine, mixtures thereof and/or copolymers thereof.
A method according to any of the claims 7 to 9, characterised in that an intermediate layer is provided between the first sheet and the second sheet wherein the intermediate layer is resilient to allow local deformation of this layer along the second surface of the first sheet or along the surface of the second sheet adjacent to the intermediate layer.
A method according to claim 10, characterised in that the intermediate layer is a fibrous layer.
A method according to claim 11, characterised in that the intermediate layer is a non woven layer.
A method according to claim 12, characterised in that the intermediate layer is a knitted layer.
Use of a textile product obtainable according to any of the claims 1 to 13 to cover a surface of a building or any other artificial or natural construction.
A textile product comprising a sheet having a top surface and a bottom surface, the textile product having polyamide yarns stitched through this sheet to form a pile on the surface of the sheet, the pile extending for a predetermined length from this first surface, the yarns being fastened to the bottom surface of the sheet by forming a layer of fused polyamide material on this bottom surface, characterised in that the yarns in the pile have a decreased amorphous content with respect to yarns of the same polyamide annealed at a temperature of between 40 and 45°C below the melting temperature of the polyamide for 1 hour.