Abstract
The invention pertains to a method to manufacture a textile product comprising a first sheet having polyester yarns fastened to this sheet to form a pile thereon, the method comprising providing the sheet, stitching the polyester yarns through the sheet to form the pile on a first surface of the sheet and loops of the yarns at a second surface of the sheet, contacting the second surface of the sheet with a surface of a hot body to at least partly melt the loops of the yarns to fasten the yarns to the sheet, wherein the second surface is actively cooled to force the temperature to be below the glass transition temperature of the polyester yarns within 60 seconds after the contacting of the second surface with the hot body. The invention also pertains to a device for applying this method.
Claims
1. A method to manufacture a textile product comprising a first sheet having polyester yarns fastened to this sheet to form a pile thereon, the method comprising: providing the sheet, stitching the polyester yarns through the sheet to form the pile on a first surface of the sheet and loops of the yarns at a second surface of the sheet, contacting the second surface of the sheet with a surface of a hot body to at least partly melt the loops of the yarns to fasten the yarns to the sheet, characterised in that the second surface is cooled to force the temperature to be below the glass transition temperature of the polyester yarns within 60 seconds after the contacting of the second surface with the hot body.
2. A method according to claim 1, wherein the second surface is actively cooled.
3. A method according to claim 1, wherein the second surface is cooled to force the temperature to be below the glass transition temperature of the polyester yarns within 30 seconds after the contacting of the second surface with the hot body.
4. A method according to claim 1, wherein the surface is actively cooled by contacting the second surface with a cold body.
5. A method according to claim 4, wherein the cold body is a stationary beam having a contacting surface that runs in essence parallel to the second surface.
6. A method according claim 4, wherein the cold body is maintained at a temperature below the glass transition temperature of the polyester yarns by actively cooling the body using convection and/or conduction.
7. A method according to claim 1, wherein the surface of the hot body has a relative speed with respect to the second surface of the first sheet.
8. A method according to claim 7, wherein the surface of the hot body is stationary, whereas the first sheet is transported along the hot body.
9. A method according to claim 1, 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.
10. A method according to claim 9, wherein the adhesive is a hot melt adhesive.
11. A method according to claim 10, wherein 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.
12. A method according to claim 9, wherein 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.
13. A method according to claim 12, wherein the intermediate layer is a knitted layer.
14. A method according to claim 9, wherein each of the first sheet, the second sheet, the adhesive and resilient layer are made of polyester.
15. Use of a textile product obtainable according to claim 1 to cover a surface of a building or any other artificial or natural construction.
16. A device for use in manufacturing a textile product comprising a first sheet having polyester 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 and loops of the yarns at a second surface of the sheet, the device comprising: a hot body that can be heated to above a melting temperature of the polyester yarns, means for contacting the second surface of the sheet with the hot body, transport means for transporting the sheet along the hot body while the second surface is in contact therewith, and cooling means for cooling the second surface to a temperature below the glass transition temperature of the polyester yarns within 60 seconds after the second surface is in contact with the hot body, and downstream of the cooling means, a means for applying a layer of adhesive to the second surface.
17. A device according to claim 16, wherein the cooling means is an active cooling means.
Description
EXAMPLES
[0032] FIG. 1 schematically shows a cross section of a textile product manufactured according to the invention
[0033] FIG. 2 schematically shows a configuration for applying a yarn melting process
[0034] FIG. 3 schematically shows details of an active cooling means
[0035] FIG. 4 schematically represents a laminating configuration
[0036] Example 1 provides process parameters for a method according to the invention
[0037] Example 2 is an example of a specific laminated textile product according to the invention
FIG. 1
[0038] FIG. 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 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 FIG. 2. The weight of this first sheet is typically about 500-800 g per m.sup.2. 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/m.sup.2. 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/m.sup.2, 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/m.sup.2.
FIG 2
[0039] FIG. 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 FIG. 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, a Teflon support 520 is present which is used to counteract a pushing force applied to the heating elements. In operation, the heating elements are moved relatively to the product, as indicated with 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.
[0040] The (intermediate) textile product to be processed with the above described configuration (the product itself is not shown in FIG. 2) consists of a 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 first heating element of 200-220° 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 polyester 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.
[0041] Downstream of the heating blocks, at both sides of the transport path 200 of the intermediate textile product to be processed, is an 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. Although depending on the glass transition temperature of the polyester one dome may be sufficient, in this embodiment, in order to cool the heated surface fast enough, preferably within 60 seconds after the textile product has been fully heated with heating body 505, two domes are used.
FIG. 3
[0042] FIG. 3 schematically shows details of an active cooling means according to a preferred embodiment of the invention. In this embodiment, the heating bodies 505 and 506 are arranged around a circular support 520′. 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 3 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 L.sub.1 of 80 mm in the transport direction, and is situated at a distance L.sub.2 of 76 mm from heating body 505. Depending on the process speed, the beam needs to be actively cooled to prevent that its temperature rises too much. Such cooling means for example exist of cooling fins in combination with a blower for cold air, or internal canals for flushing the beam with a cooling liquid. At process speeds below 1-2 meters/minute active cooling of the beam is generally not required. Above a process speed of 3 m/min, active cooling is usually required. The beam is pressed against the second surface 4 of the textile product 2 to provide for an additional calendering action. Roller 307 is used to counteract the pressing action and provide for the option to use a high pressing force. 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.
FIG. 4
[0043] FIG. 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 FIG. 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 FIG. 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. In practice other means for applying a layer of adhesive could be applied, such as using a row of dosing needles, using a doctor blade, spraying, dosing fine particulate adhesive grains, etc. 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 FIG. 1) is thereafter wound on roller 604. In an alternative embodiment the fibre-binding process as described in relation with FIG. 2 and the lamination process take place in line. In that case, the fibre-binding set-up as shown in FIG. 2 could be placed between roller 600 and roller 601 (in which case roller 600 holds an intermediate textile product, of which the yarns are to be bound by melting). In the shown embodiment of FIG. 4, 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 2 m/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 500 g/m.sup.2. This is adequate to glue the target sheet 215 to the primary backing (i.e. the first sheet).
[0044] 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/m.sup.2 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/m.sup.2. In a still yet other embodiment HMA may be applied in an amount from 0.1 to 600 g/m.sup.2.
Example 1
[0045] 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 FIG. 3 are given. At a process speed of 1 m/min, the cooling beam 305 is not actively cooled. During the process, the beam will obtain an equilibrium temperature which is low enough to be able and actively cool intermediate product 2 such that the temperature at the second surface is forced to be below the glass transition temperature of the polyester (typically below 150° C.). The textile product is heated with heating body 505 to a temperate of 260° C. When the product arrives at the cooling beam, its temperature is still above the glass transition temperature, namely around 190° C. The beam actively cools the surface very quickly, due to the intensive contact, to a temperature of about 145° C. at the end of the length L.sub.1 of the beam. This temperature is reached within 10 seconds after the second surface is heated with heating body 505. This is well below 60 seconds which are typically needed to prevent that molten PET can rearrange to arrive at a surface that is less favourable for gluing.
Example 2
[0046] 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 FIG. 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/m.sup.2 obtained from Freudenberg Vliesstoffe SE & Co. KG Neuenburg, Germany. This primary backing is tufted with a cut pile of 100% PET yarns obtained from Pharr Yarns LLC, McAdenville, N.C., USA, at 12 needles per inch. The polyester 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 FIG. 2. The total weight of this tufted sheet is about 700 g/m.sup.2. 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/m.sup.2. 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/m.sup.2 (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/m.sup.2. The laminated textile product appears to be very durable and resistant against delamination.
