WO2009068848A2

WO2009068848A2 - Zip fastener

Info

Publication number: WO2009068848A2
Application number: PCT/GB2008/003864
Authority: WO
Inventors: Shigeyoshi Takazawa; Meirion Williams; Steven Thomas
Original assignee: Ykk Europe Limited
Priority date: 2007-11-30
Filing date: 2008-11-26
Publication date: 2009-06-04
Also published as: GB0723494D0; WO2009068848A3

Abstract

A zip fastener (1) has a fabric tape (5, 6) having coupling elements (7, 8) on an edge of the tape (5, 6). A coating (16, 18) of a transparent thermoplastics material is provided on at least one surface (20, 22) of the tape (5, 6). A pattern (26) may be printed on the tape surface (20, 22) and covered by the transparent layer (16, 18). Also described is coating layer having an embossed or three dimensional pattern on the coating upper surface.

Description

Title: Zip Fastener

DESCRIPTION

The present invention relates to a zip fastener and more particularly to a zip fastener in which the fastener tapes have a coating of plastics material.

Most usually a zip fastener tape is woven or knitted, for example of polyester thread, and fastener elements are crimped or moulded onto a reinforced edge of the tape, or a continuous coil which forms the fastener elements is woven or knitted into the tape or stitched to the tape surface at the edge of the tape.

In one method of forming a waterproof fastener, coupling elements formed by a continuous coil of plastics fibre are mounted on one surface of the tape, near the tape edge, and a polymer layer such as a rubber or neoprene layer is extruded onto the other surface of the tape to form a waterproof coating. The polymer layers on each tape abut to form a seal when the coupling elements are engaged to close the fastener. The coating is black, which limits the usefulness of the fastener to industrial use, some sportswear or a limited range of fashion goods.

EP-A-1057423 and EP-A-1175842 show a waterproof fastener having coil type coupling elements and waterproof layers which abut in a plane perpendicular to the plane of the tapes.

US-A-5709766, EP-A-1150586 and EP-A-1629740 describe a process for laminating a polyurethane coating to a fabric layer by applying an intermediate coating of bonding material. A multilayer polyurethane coating may be used. The coating layers are applied to the joined fastener tapes and then slit along the centre line of the fastener.

WO02/063988 suggests extruding a coating layer over the complete fastener, that is on both surfaces, to encapsulate the fastener, before slitting the layers.

It is well known to dye the fastener tape for fashion use. A single colour dyeing process is well known and provides colour-fast tapes. For patterned tapes, a pattern can be printed on to the tape. However printed patterns, particularly ones printed using ink-jet printing, tend to fade during prolonged use.

A first aspect of the present invention provides a zip fastener having a woven or knitted fabric tape having coupling elements thereon, wherein a coating of a transparent thermoplastics material is applied to at least one surface of the tape.

Preferably the thermoplastics material is extruded onto the tape surface.

Preferably the thermoplastics material is polyurethane.

Preferably the tape has a pattern printed on the tape surface.

It has now been found that coating the printed surface with a transparent thermoplastics layer provides a more durable pattern. It is believed that the pattern is partially absorbed into the thermoplastics layer. Using a transparent thermoplastics layer provides other advantages. For example, it is possible to incorporate a thermochromic dye or a pearlescent material into the polymer forming the transparent layer.

Surprisingly, it has also been found that in a waterproof fastener, in which the transparent layers on the respective tapes abut above the line of the fastener elements, the line of joining of the elements tends to be less visible. This is particularly so with layers which form a lip which, in the unclosed state of the fastener, extends beyond the edge of the tape and over the line of the fastener elements so that when the fastener is closed the lips abut to form a raised shape, particularly a generally triangular shape, above the line of the elements. Presumably this is due to the effects of refraction or reflection by the transparent layer.

It has also been found that it is possible to texture the surface of the polymer coating on the fastener tape, for example by passing the tape under a roller die as it leaves the extrusion head. This technique may also be used when applying a neoprene or rubber coating, providing a textured surface which is more easily gripped.

The present invention is applicable to waterproof fasteners but is not limited thereto.

Other aspects and preferred features of the invention will be apparent from the following description and the accompanying claims.

The invention will be further described by way of example with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a first embodiment of a zip fastener according to the invention;

Figure 2 is a cross-section along the line N-Il of Figure 1 ;

Figure 3 is a cross section through a second embodiment of the invention, similar to the cross-section of Figure 2;

Figures 4a and 4b show cross-sections through a third embodiment of the invention, similar to the cross-sections of Figure 2, Figure 4a showing the fastener stringers separated and Figure 4b showing the stringers joined to form a chain;

Figure 5 illustrates a manufacturing process of the invention;

Figures 6a and 6b illustrate a fourth embodiment of a zip fastener of the invention, and

Figure 7 illustrates a roller of the apparatus of Figure 5.

Referring to Figures 1 and 2, a zip fastener 1 is shown of the general type described in EP-A-1150586 the contents of which are incorporated herein by reference. The fastener 1 comprises a chain 2 formed of two stringers 3, 4. Each stringer comprises a tape 5, 6 of woven polyester fabric. A continuous coil 7,- 8 forming coupling elements is stitched or woven into the tape edge 9, 10, as well known in the art. The coils 7, 8 are mounted on the underside 12, 14 of each tape 5, 6. A layer 16, 18 of transparent thermoplastics material, in this case polyurethane, is extruded onto the upper surface 20, 22 of each tape 5, 6. Other thermoplastics which could be used include polyethylene, polypropylene and polyvinylchloride. The thermoplastics material bonds to the tape during an extrusion process, which will be described hereinafter.

Typically, the finished fastener will include a slider, for opening and closing the chain, and end stops for limiting the movement of the slider. Such features are well known in the art and need not be described further here.

Fastener 1 is of the waterproof type. The layers 16, 18 form a waterproof membrane and abut at a plane 24, perpendicular to the plane of the tapes 5, 6. The present invention is applicable to other waterproof fastener types, such as described in EP-A- 1057423, the contents of which are incorporated herein by reference, but is not limited to waterproof fasteners perse, or fasteners using continuous coil type coupling elements.

Polyurethane layers 16, 18 are substantially transparent. The upper surfaces 20, 22 of the tapes 5, 6 are provided with a printed pattern 26, in this case numerals, by ink-jet printing onto the tape surface 20, 22 prior to application of the polyurethane layers 16, 18.

As noted above, a polymer coating layer 16, 18 may be applied to other types of zip fastener.

Referring to Figure 3, this shows a second embodiment of the zip fastener of the invention, in which the coating layers 16', 18' are applied to tapes 5', 6' having fastener elements 40, 42 crimped or moulded on to the tape edge 9', 10'. Also, as seen in Figure 3, the polymer layer 16', 18' does not extend over the coupling elements.

In the further embodiment of Figures 4a and 4b, which is similar to the fastener shown in EP-A-1057423, the coating layers 16, 18 are applied to the separated stringers 3,4. The coating layers form sealing lips 16a, 18a, which extend laterally beyond the edges 9, 10 of the tape 5,6 and over the continuous coil fastener elements 7, 8. The lips 16a, 18a extend up at an angle to the plane of the fastener tapes 5, 6 and abut to form a raised area A, that is raised above the general plane P-P of the stringers 3,4 to form an inverted V shape or triangular shape when the fastener stringers 3, 4 are joined (Figure 4b). This raised region A has been found to reduce the visibility of the join line of the coiled elements when the tape is viewed from the upper side. Also, as shown in this embodiment, the coating layer 16, 18 may extend beyond the outer edge 44, 46 of the tape 5, 6. The coating layer may also extend over the underside of the tape 5, 6.

To manufacture a fastener of the invention, the tape is fed through an extrusion die set under tension and the thermoplastic coating extruded under pressure onto the surface of the fastener tape to cause the thermoplastics to bond to the tape.

Referring to Figure 5 a fastener chain 2 comprising tapes 5, 6 and meshing coils 8, 10 is fed through an ink jet printing machine 30, where a pattern 26 is printed onto the upper surfaces 20, 22 of the tapes 4, 6. After the ink is set, the chain is drawn through an extrusion die set 36, tensioned by rollers 34 and a layer 16, 18 of transparent polyurethane is extruded onto the upper surfaces 20, 22 of the tapes 4, 6, over the printed pattern 26. Thereafter the stringer is fed to a slitting machine 38 where the coating layer is slit at the joining plane 24. As noted in the description of the embodiment of Figures 4a and 4b, the stringers 3, 4 may be fed though the production apparatus separately, or in parallel but separated from one another.

Also, the printing stages and the slitting stages may take place separately to the extrusion stage, for example in different locations.

Also shown in Figure 5, is an embossment stage 48 for forming a three dimensional pattern or relief on the upper surface of the polymer coating layer. Stage 48 comprises a roller 50 having a textured surface, that is having a three dimensional surface pattern which may be a regular pattern or random, which is pressed against the upper surface of the polymer layer 16, 18 as it leaves the extrusion head 36, the chain 2 being supported from below by an anvil 51. The polymer layer 16, 18 is still soft as it exits the extruder 36 and so a pattern is formed in the upper surface of the layer 16, 18. As noted above, this embossment step may be used with the prior art neoprene or rubber coated fasteners as well, the fastener being fed though an extrusion head 36 to apply the neoprene layer and then underneath the pressure roller 50 to apply an embossment to the surface of the neoprene layer. With a thermoplastics coating layer 16, 18, the embossment stage may be performed at a later time, the thermoplastics layer being heated before embossing the pattern on the layer.

Referring to Figures 6a and 6b, these show another embodiment of the invention in which a polymer coating layer 16", 18", in this case neoprene, has been extruded onto the surface of the tape 5, 6. Thereafter, the surface of the polymer layer is embossed, for example by passing the heated layer under a roller 50 having a textured surface to form a three dimensional pattern 50 in the surface 52 of the thermoplastics layer, such as described with reference to Figure 5 above. Pattern 56 consists of ridges 58 and grooves 60 running diagonally across the upper surface 52. These can be formed by corresponding helical grooves and ridges 62, 64 formed in the surface of the roller 50 of Figure 5, as illustrated in Figure 7. The embossment may be done at the point of extruding the neoprene layer onto the tape 5, 6, while the layer is still soft, or sometime thereafter if a thermoplastics polymer which can be readily reheated and softened is used. By embossing the surface of the coating layer, that is forming a three dimensional pattern in the surface, the slipperiness of the layer is reduced, which will facilitate stitching or bonding the coated tape to a substrate as well as providing an attractive surface. As mentioned, this embossment process is applicable to rubber or neoprene coatings as well as to the thermoplastic coatings described above.

Claims

1. A zip fastener having a fabric tape having coupling elements thereon, wherein a coating of a transparent thermoplastics material is provided on at least one surface of the tape.

2. A zip fastener as claimed in claim 1 , wherein the thermoplastics material is extruded on to the tape surface.

3. A zip fastener as claimed in claim 1 or 2, wherein the thermoplastics material is polyurethane.

4. A zip fastener as claimed in claim 1 , 2 or 3, wherein the tape has a pattern printed on to the tape surface underneath the coating.

5. A zip fastener as claimed in any one of claims 1 to 4, wherein a thermochromic dye is incorporated in the coating.

6. A zip fastener as claimed in any one of claims 1 to 4, wherein a pearlescent material is incorporated in the coating.

7. A zip fastener as claimed in any one of claims 1 to 6, wherein the coating forms a waterproof layer, the coating layer being provided on each tape of the fastener and the layers abutting at a centre line of the fastener to form a seal.

8. A method of applying a coating to a zip fastener tape, the method comprising feeding the tape through an extrusion die and extruding a layer of transparent thermoplastic material on to the tape.

9. A method as claimed in claim 8, wherein the tape incorporates a pattern.

10. A method as claimed in claim 9, wherein the pattern is printed onto the tape.

11. A method as claimed in claim 10, wherein the pattern is printed by ink-jet printing.

12. A zip fastener having a waterproof polymer coating formed on a surface of a tape of the fastener, wherein a pattern is embossed in the surface of the coating.

13. A zip fastener as claimed in claim 12, wherein the polymer is neoprene.

14. A method of manufacturing a zip fastener, the method comprising feeding a tape of the fastener through an extrusion die and extruding a polymer coating on to a surface of the tape to form a waterproof layer, and feeding the tape under a pressure roller having a textured surface to emboss a pattern into the surface of the polymer layer.

15. A method as claimed in claim 14, wherein the pressure roller is positioned at an outlet of the extrusion die.

16. A method as claimed in claim 14 or 15, wherein the polymer is neoprene.