IMPROVEMENTS IN AND RELATING TO FABRIC BONDING

Abstract: A method for making a shaped object is disclosed. A mould (14) is disposed between two layers of fabric (10a, 10b), with joining layer (12) layer therebetween. The upper fabric layer (10b) has a greater surface are a than the lower layer (10a), so that the final garment has a natural curvature. Further embodiments respectively describe how garment inserts may be joined by a vacuum draw-down process (figure 10) and by the use of adhesive cups (figure 12).

Description: IMPROVEMENTS IN AND RELATING TO FABRIC BONDING The present application relates in general to the field of fabric bonding. One aspect of the invention is related to mass-produced specialist gloves and related covers. Another aspect relates to siliconised materials, non-stick materials such as polytetrafluoroethylene (PTFE) and other materials which cannot readily be joined with adhesive or by welding. The technique is applicable throughout fabric technology, but a particular application in the formation of airbags is given as an example. The application relates to new methods for constructing such goods which results in an easy to use product at an economical cost. Specialist protective clothing, such as gloves and boots and liners are required for many applications. For example, waterproof gloves are used in the outdoor leisure industry; heat insulated gloves are used for handling very hot or cold items in industry and fireproof gloves are used by firemen. It is known to mass produce gloves for these industries by joining together two flat fabric sheets, for example, according to the method of Patent Application WO 99/64240 to Liteliner, being a continuation in part of US Serial Number 08/697648 (now US Patent 5,766,400). Such gloves are two-dimensional, with two correspondingly shaped pieces of fabric joined by seams. A hand is three dimensional, with an opposed thumb, and so these two- dimensional gloves do not fit well and limit the free flexing of fingers. Therefore, two dimensional gloves are typically made oversized. This results in them being very bulky, with considerable excess material and not particularly flexible. Gloves which more accurately fit the shape of the hand are of course everyday items, but are made from several or many piece of material with multiple seams. (An exception is the method used to make latex gloves; however, this is applicable only to materials which can be formed from a spray and is not usable with waterproof breathable fabrics) An item with multiple seams has, in general, less mechanical strength and durability of waterproofing than a comparable item with one seam. Needless to say, configuring the sealing apparatus of WO99/64240 to produce a glove with multiple seals would not be cost effective. One aim of the present invention is to provide articles and methods of' making articles which are more accurately shaped to fit the three dimensional shape of a user whilst requiring a minimum number of seams. Furthermore, the joining technique disclosed in WO99/64240 and many other fabric joining techniques require piece of material to be joined along a flat (i.e. two-dimensional) intersection. A further aim of the present invention is to provide three- dimensional articles and method of making such articles which involve two-dimensional joins, thereby enabling the articles to made with a range of joining techniques. According to a first aspect of the present invention there is provided a method for making a shaped object from sheets of synthetic material comprising the steps of: (a) placing a first sheet of material in proximity to a second sheet of material such that the edges of the first and second sheets of material correspond; and (b) sealing together the edges of said sheets of material; characterised in that a mould is disposed between the first and second sheets of material, the mould having an upper surface for contact with the first sheet of material and a lower surface for contact with the second sheet of material, the mould being shaped such that the surface area of the upper and lower surfaces are different and also being shaped such that the first and second sheets of material are in contact where they are to be sealed together or are separated only by layers intended to be incorporated into the final seam. Preferably, the first sheet of material will be placed against the mould by laying a first edge of the first sheet of material along one part of the mould and then moving sequentially across the mould, pressing the rest of the first sheet of material against the mould progressively. In one embodiment, the first sheet is pressed sequentially from one edge of the mould. Alternatively, the first sheet is pressed progressively from a high point of the mould to a low point. More preferably, a progressive tool will be used to press said first sheet of material against the mould and the second sheet of material. Alternatively or additionally, vacuum draw-down may be used to bring a sheet of material into contact with the mould. The first and second sheets of material may be separated where they are to be sealed together by a thermoplastic joining film. The shaped object may be selected from a group including gloves, boots, jackets and trousers. According to a second aspect of the present invention there is provided a shaped object comprising two sheets of flexible material, the edges of which correspond, joined around part of their perimeter by a waterproof seal, wherein one sheet of flexible material is of greater surface area than the other sheet of material. The shaped object may be selected from a group including gloves, boots, jackets and trousers. According to a third aspect of the present invention there is provided a method of making a composite garment comprising the steps of: (a) forming a laminate of a synthetic membrane and a fabric sheet, the synthetic membrane having an adhesive layer thereon; (b) joining edges of two fabric sheets or two parts of the same fabric sheet to each other around part of their perimeter so as to form an insert for a garment; (c) inverting said insert for a garment and placing said insert for a garment within an outer layer of a garment; (d) placing a shaped inner layer of a garment within said insert, said inner layer having an adhesive layer thereon; (e) lasting the inner layer and insert to the outer layer of a garment and applying heat thereto so as to melt the adhesive layers and form a composite garment. The edges of two fabric sheets or two parts of the same fabric sheet may be joined using a thermoplastic joining layer. According to a fourth aspect of the present invention there is provided a method of making a composite garment, the method comprising the steps of: (a) forming a garment shaped fibrous layer around a mould, (b) placing a garment liner around said garment shaped fibrous layer, the garment liner having a surface in contact with the garment shaped fibrous layer, the surface having a thermally activated adhesive thereon; and (c) heat activating the thermally activated adhesive, thereby joining the garment liner to the garment shaped fibrous layer. The garment may be placed within an outer garment layer. The garment shaped fibrous layer may be formed around a mould using the method of the first aspect. The present invention aims to provide a better shaped glove, or other shaped fabric product, using a simple sealing method related to that of O99/64240 and minimal, preferably one, sealing steps. A further aim of the invention is to provide an improved manufacturing process for a garment, according to the fifth aspect. According to a fifth aspect of the invention, there is provided a method for forming a garment, the method comprising the steps of: - providing an outer surface of a first insert with an adhesive; - placing the first insert over a moulding, said moulding having a hollow centre and perforations formed in a surface thereof; - placing a second insert over the first insert; - reducing the pressure within the moulding, thereby drawing the second insert towards the first insert, and; - bonding the first and second inserts together. The adhesive may be scattercoated on the outer surface of the first insert. The adhesive may be applied to the first insert before or after it is placed over the moulding. According to a sixth aspect of the invention, there is provided a method for forming a garment, the method comprising the steps of: - placing a first insert over a moulding, said moulding having a hollow centre and perforations formed in a surface thereof; - providing an inner surface of a second insert with an adhesive; - placing the second insert over the first insert; - reducing the pressure within the moulding, thereby drawing the second insert towards the first insert, and; - bonding the first and second inserts together. The adhesive may be scatter coated on the inner surface of the second insert. The adhesive is preferably a heat sensitive adhesive, for example a thermoplastic. The method may include the additional step of heating the first and second inserts, subsequent to the step of drawing the inserts together. The heating may be accomplished by applying Infra Red radiation to the inserts. Alternatively, the heat may be applied to the inserts via the moulding. According to a seventh aspect of the invention, there is provided a method of forming a garment, said method comprising the steps of: - placing a first insert over a moulding; - providing at least one protruding portion of the first insert with one or more adhesive cups; - placing a second insert over the first insert including the one or adhesive cups, and; - bonding the first and second inserts together. The garment may be a glove, in which case the moulding is hand-shaped and the protruding portions are digits of the glove. The adhesive cups may be thimble-shaped. They preferably extend to a distance no further than the first joint from the tip of a finger. In another embodiment, the garment may be a sock or a lining for a boot, in which case the mould is in the shape of a foot. The protruding portion may be the toe-cap region, and the adhesive cups preferably extend no further than the balls of the feet. Adhesive cups may also be provided over a heel region. The adhesive cups may be manufactured from molten adhesive by a dip process. Alternatively, they may be pre-formed from a sheet adhesive. At the present time a wide variety of techniques are known for the joining of fabric material sheets. A subset of these techniques are also suitable for forming airtight or watertight seals. Fabrics are conventionally joined by stitching seams together and, if a waterproof seal is required, taping the seams. Recent innovations such as WO 99/64240 (to LiteLiner Technology) have led to improvements in waterproof joins for fibrous but non-containable fabric composites. However, there remain important categories of material for which there is currently no convenient joining process which can be applied economically on an industrial scale. This applies particularly to siliconised fabrics or fabrics containing or coated with polytetrafluraethane (PTFE) . These categories of materials are made in sheets and there is no economically viable way presently known to join these sheets together in a mechanically strong and waterproof seal. One aim of the present invention is to provide a mechanically strong method for joining sheet materials in general. The method being particularly relevant for joining of materials such as siliconised or PTFE fabrics which cannot readily be joined by adhesive or conventional welding techniques. A particular technological field where this lack of a industrially effective joining technique is felt is the airbag industry. Currently, concern is growing in the airbag manufacturing industry about litigation cases, with airbag manufacturers being held responsible for abrasive damage being caused to passengers when air-bags are activated. Therefore, it would be desirable to make air bags from the smoothest possible materials such as siliconised fabrics, PTFE or fluorocarbon sheets. However, this has so far proved difficult. In order to use these materials it is necessary to devise an economically viable and substantially airtight joining technique to form the sheets into a bag. An additional aim of the present invention is therefore to provide a method of joining sheets of materials together which is suitable for joining together smooth fabrics for use in airbags. At the present time, airbags are made from smoothly woven fibrous materials and recent innovation has tended towards finding smooth coatings for airbags rather than new materials for the airbags per se. Recent examples of such developments are described in, for example, US5, 928,721 to Milliken and US5,881,776 to Safety Components Fabric Technologies. According to an eighth aspect of the present invention there is provided a method of joining sheet materials wherein two sheet materials have join regions to be joined to each other, the method comprising the steps of: (a) forming a plurality of holes in the join regions of two material sheets; (b) arranging said material sheets so that the join regions are in face to face contact with a thermoplastic joining layer which separates them; (c) applying heat to said join regions in such a way as to cause the thermoplastic joining layer to melt and flow through holes; and (d) allowing the thermoplastic joining layer to cool, forming a bond between the material sheets. Preferably, the material sheets are siliconised materials. Alternatively, the material sheets may be PTFE-containing materials. The plurality of holes may be formed using a pulsed laser. The plurality of holes may be formed using a perforating member. Alternatively, the plurality of holes may be formed using ultrasound. Preferably, heat will be applied to the region of material sheets which are to be joined by an RF source. The material sheets may be underlaid and overlaid with further thermoplastic joining layers. Covering layers may be situated between the regions of material which are to be joined and a source of said heat to prevent unwanted adhesion. According to a ninth aspect of the present invention there is provided a method of joining sheet materials wherein two sheet materials have join regions to be joined to each other, the method comprising the steps of: (a) forming a plurality of holes in the join regions of two material sheets; (b) arranging said material sheets so that the join regions are in face to face contact; and (c) applying a molten thermoplastic material to said join regions in such a way as to cause the molten thermoplastic material to melt and flow through holes; and (d) allowing the thermoplastic material to cool, forming a bond between the material sheets. Preferably, the molten thermoplastic material consists of two thermoplastic sheets in face to face contact with the join regions so the both join regions are sandwiched between the thermoplastic sheets, wherein said thermoplastic sheets are then melted. According to a tenth aspect of the present invention there is provided an article comprising two or more sheets of material joined using the method of the eighth or ninth aspect. According to an eleventh aspect of the present invention there is provided an airbag made by joining two sheets of low- friction material to each other using the method of the eighth or ninth aspect. The first aspect of the invention will now be illustrated with reference to the following Figures in which: Figure 1 is an exploded cross-sectional view of a composite fabric seam assembly according to the present invention; Figure 2 shows the mould for use in the present invention; Figure 3 shows a glove according to the present invention whilst worn from a) the side; b) underneath; c) looking down on and d) edge on; Figure 4 shows, in perspective view, a glove according to the present invention without a hand therein and at rest; Figure 5 is a perspective view of a glove end on, showing the gussets between two fingers; Figure 6 shows progressive tooling according to the present invention from a) above and b) end on; Figure 7 shows a cross-section through a seam joined using a thermoplastic joiner layer; Figure 8 shows a cross-section through a waterproof insert; and Figure 9 shows a cross-section through a comfort insert. Figure 10 shows a moulding in accordance with one embodiment of the invention. Figure 11 shows a bonding method in accordance with one embodiment of the invention. Figure 12 shows a bonding method in accordance with an embodiment of the invention. Figure 13 shows a bonding method in accordance with the invention. Figure 14 shows a plan view of a sheet material joining assembly; Figure 15 shows a close-up plan view of a plurality of holes in sheet material; Figures 16a through 16d shows various conformations of material and joining layer in cross-section envisaged by the present invention; and Figure 17 shows a cross-section of a join formed between two sheets of material. 1 Figures 18 and 19 show apparatus for forming microholes in a sheet material The present invention is a shaped garment or other cover and a method for manufacturing the same. By way of an example, a glove and method of manufacturing the glove will be shown. Figure 1 is an exploded cross-sectional view of the various layers of material which are assembled around a mould to produce the final product. Fabric pieces cut into the shape of a glove 10a, 10b are overlaid and underlaid with membranes 11a, lib. A thermoplastic joiner film 12 is sandwiched between the glove shape 10a, 10b and as in WO 99/64240 is positioned so as to straddle the edges of the glove shape 10a, 10b. An optional mesh fabric layer 13 can be used. Additional layers for specialised applications eg tie layers to reduce approved mechanical strength should be used where required. Alternatively, only one layer might be used above and below the mould. For example, an aramid fibre material with a waterproof scrim might be used for each of ' the top and bottom sheets. The layers of fabric are assembled around a glove shaped mould 14. The example mould shown in Figure 2 has a flat underside and curved upper surface. This means that when material is fitted over and under this mould, there is a larger surface area of material overlaying the top surface than underlying the bottom surface. The method by which the material is fitted over the mould is important and is described further below. The layers of fabric are then joined together. In one example, non-containable fibres as defined in WO99/64240 may be joined using induced melting of the joiner layer substantially as described in WO99/64240. The resulting glove is then trimmed and, for many applications, turned inside out. Alternatively any fabric joining technique suitable for the type of material used may be employed. In some embodiments no joining layer will be required. As there is a larger surface area of material above the mould, the resulting glove tends to curve, more naturally fitting the shape of a real hand. In particular, the thumb sits naturally below the line of the other fingers and, by selection of appropriate design parameters, sits in the correct opposable position of a hand. The resulting glove is shown in Figures 3 and 4. Glove 30 has a surface 31 made from a non-containable fabric eg, KEVLAR® brand aramid. The upper surface 31 is joined to the lower surface (not shown) via an encapsulated seam 33. It can be seen from the diagram that this glove has a fold line 35 which is above the thumb, therefore when this glove is worn the thumb will sit naturally at the appropriate angle to make it most comfortable to wear and use. A second design feature is most clearly seen in Figure 5. The upper material surface 31 is folded down the gap between two fingers thereby forming a gusset 34. This contrasts with the arrangement in a simple glove made from two pieces placed flat on top of each other before seaming. In the previously known form, the material fingers have to be much wider than a wearers fingers; as there is no slack in the material when it is welded, they have to be wide to encompass the full circumference of the wearers finger. Such gloves are hard for the wearer to flex. In the present invention, although the lower material surface 32 is simply a two-dimensional cut out, the upper surface 31, being folded down, has slack once the mould is removed, leaving it in the shape of a finger, with appropriate gussetting to allow the fingers to be flexed. As a result of this, the glove is substantially more flexible and easy to use than the previously known two-dimensional form. The process has the additional benefit of being more economical than the prior techniques. The reduced cost results from a reduced amount of fabric used and a reduced amount of joiner is required, due to the shorter joing seam at the perimeter. In order to achieve the features of (a) having more material in the top surface than the lower surface, thereby disposing the glove to fit the curve of a hand and (b) of having a gusset structure between fingers, a new method of positioning the material has been devised. A simple construction process could use a tool to press the top material layers down, onto the mould, against the lower material layers. This would, however, lead to creasing and stretching in the material. A better finished product would be prepared by allowing the upper material to be moved across the mould with a progressive drawing tool. An example arrangement is shown in Figure 6 which shows two fingers 36 of the mould from above. Individual tools 40 are engaged to press the material down onto the mould sequentially running in one direction across the mould. In Figure 6b, one finger can be seen end-on and in cross-section through line AA. By automatically placing consecutive tools in turn, the material flows across the mould. The tools may be shaped as in Figure 6b so that they push the material downwards as well as pressing it against the mould, further helping it to flow across the mould. This invention allows the production of gloves and boots and other shaped items to be made using a simple one-step sealing technology. Alternatively, a progressive tool may be used to sequentially press down the fabric starting from the highest point on the mould (for example the centre of the back of the hand) , and progressively moving outwards to the lower points. Instead of using a number of consecutive tools, it may be possible to use a one piece tool. Alternatively, vacuum draw-down might be used to pull the upper layer down over and around the mould, as described later. Although one specific sealing technology and one specific arrangement of fabric layers is described here, it will be clear to one skilled in the art that many other joining techniques could be used and many types of fabrics joined. An important benefit of the present invention is that the junction region between the upper and lower fabric layers is flat, making it easy to apply a press to the junction. The resulting materials are well-shaped to be used on real three-dimensional objects such as hands and feet and so the invention has provided an economic method of producing high quality garments and inserts for garments. There is additionally disclosed herein an improvement to the construction of shaped garments made using a lasting process. Within the prior art it is known to form linings within garments such as boots using a lasting process and known to use this to form boots having a waterproof, breathable fabric such as microporous PTFE therein. These materials can be difficult to work with. For example, PTFE membranes with microscopically minute pores are readily broken and rendered non-waterproof by sewing or stitching. One solution to the problem of incorporating such a membrane within a garment is disclosed in US Patent Number 4,520,056 to Jackrel. In this construction, a glove or other garment involves an inner insulating layer and an external covering layer sewn to the inner insulating layer around the wrist portion wherein a gas-permeable liquid impermeable membrane is confined within the recess between the inner and outer layers but left unattached to either layer. Were this membrane to be sewn to either the inner or external layer its waterproof properties would be damaged. A construction such as this does however remain limited in terms of mechanical rigidity. It would therefore be desirable to join the waterproof layer to the inner or outer layers of a garment without damaging the waterproof layer. US Reissue Patent 34,890 to Gore Enterprise Holdings Inc provides a shoe with a sock-like waterproof liner joined to the outer of the shoe only round the ankle portion. US Patent 5,766,400 and PCT Application WO 98/09011 both to Liteliner LLC disclose methods of producing pre-f bricated multi-layered products in which a thermo- plastic joining film strategically placed between layers and melted in place is used to enhance bonding. This technology provides very strong joins, but can be difficult to use for gloves which need to tolerate high temperatures. For example, gloves in the fire industry must withstand temperatures well in excess of 100 °C; however, thermoplastic films with melting temperatures above around 80°C have been found by us to be hard to use in forming these products as it is difficult to get them to melt in si tu and form an appropriate strength bond. Therefore, it would also be desirable to provide a method for joining fabric materials to each other and to synthetic films which is better adapted for use in high temperature applications. Figures 7 to 9 illustrate an alternative configuration; in this example, the garment is a boot. This boot comprises an outer waterproof insert which fits- within a standard shoe and an inner insert which is a comfort insert that fits within the waterproof layer. The teaching of the prior art documents referenced above is that there is no good way to fixably join the waterproof insert to the comfort insert and outside of the shoe. We herein propose a method of better joining the layers of a multilayer garment, enclosing a waterproof breathable membrane therein. Figure 7 shows a cross-section through a waterproof insert 20. The hydrophilic or microporous membrane 21 may be joined to a fibrous backing fabric 22 using the techniques of WO99/64240 to Lineliner. A seam may be formed at the location shown in Figure 8 by then joining the fabric layers 22 to each other using either a thermoplastic adhesive 23, using the technique of US Patent 5,766,400 or PCT Application 98/09011 or 99/64240, or using any other joining technique appropriate to the materials. By putting a scatter coat adhesive 24 on the microporous membrane 21 the insert can be readily joined to a comfort insert 25 which is lasted therein and consists of comfort layer such as foam or felt 26a overlaid with a face fabric 26b and joined by an appropriate method. In the comfort insert there is no waterproof layer to be damaged and so stitching 27 may be used to join these layers. The resulting product is a comfortable waterproof shoe in which individual layers therein are joined to each other rather than being free to move, improving the lifespan of the product and reducing any discomfort for the wearer due to movement of the layers. It will be clear to one skilled in the art that this construction can be used to provide many different types of article such as gloves, boots, jackets, socks, shirts, trousers etc. A further embodiment is now described. A prefabricated inner glove made from a layer of any type of fibrous material (aramid, acrylic, wool, cotton etc.) is placed around a 3D mould using the technique of the first or second embodiment of the present invention. Alternatively a 2D mould could be used and the fabric might be simply placed around the mould. A glove liner laminate comprising a plurality of layers selected from membranes (particularly waterproof, breathable membranes) and tricots and coated with scattercoat adhesive is placed around the inner glove, with the adhesive in contact with the inner glove. The adhesive is then activated by heating, giving a finished glove liner assembly. The glove liner assembly is then placed within a known outer glove, selected depending on the end use of the glove, by standard glove manufacturing techniques. Figure 10 shows a moulding 110 in the shape of a hand. The figure shows a section 111 cut away from the moulding in order to display the interior of the moulding. The moulding is hollow, and the surface of the moulding 112 is covered in perforations 113. Attached to the base of the moulding is a tube 116 which is attached to a vacuum pump (not shown) . A second tube 117 is optionally provided, attached to a compressor for providing a pressure (not shown) . The moulding is attached to a steel plate by means of a steel tube weld 118. Figure 11 shows the moulding used in the manufacturing process. In use, a preformed or knitted comfort insert is placed over the moulding 110. A second insert 122, for example a waterproof, fireproof or gas-proof insert, to be placed over the comfort insert on the moulding is provided with adhesive on its internal surface. The adhesive is a heat sensitive adhesive such as a thermoplastic, and is scatter coated on the internal surface. The second insert is placed over the comfort insert, and a clamp (not shown) is provided around the wrist portion of the two inserts to provide an airtight seal between the two layers. The clamp may be of any suitable type, for example an elastic band, or an inflatable collar. The clamp prevents air from being drawn in between the two inserts when the vacuum pump is activated. The vacuum pump is activated by a foot-operated valve (not shown) . The vacuum pump, attached to the moulding via tube 116, causes the pressure to be lowered within the moulding. The resulting effect is that the outer insert is drawn down onto the comfort insert, providing a good contact between the two inserts. Subsequently, heat is applied to the inserts in order to raise the temperature, thereby melting the scattercoat adhesive and bonding the two inserts together. The heat may be supplied by any suitable source, for example an infra red radiation source. Alternatively, the moulding may be provided with heating elements in order to heat the inserts form the inside, or hot air may be used. When the inserts are bonded, the vacuum is released. The glove may then be blown off the moulding by increasing the pressure inside the moulding via a compressor (not shown) attached to the moulding via tube 117. As an alternative to the vacuum pump, a simple cylinder may be used to reduce the pressure in the moulding. The same cylinder could also be used to supply the increased pressure with the moulding. In an alternative method, the scattercoat adhesive may be added to the external surface of the comfort insert, instead of, or in addition to, the inside of second insert. In this case, the adhesive may be applied to the comfort insert before or after it is in position on the moulding. If required, further layers may be provided in the garment. This aspect of the invention is intended to embrace the joining of any two suitable fabrics layers by the techniques described herein. In this regard, although the term "insert" has been used in order to describe the second layer of fabric, placed over the comfort insert, it is evident that the above method can be used to bond a single insert to an outer layer of a glove, such as a leather or fabric layer. In addition, although the above embodiment discloses the formation of a glove, it will be obvious to one skilled in the art that the techniques can be applied to other articles . In particular, a sock, or lining for a boot or shoe could be made with the above techniques, using a moulding in the shape of a foot. It is clear that the features of the first aspect of the invention can be combined with the fifth aspect above. Specifically, the comfort insert, the second insert (eg a waterproof, fireproof or gas-proof insert) or any additional layers may be formed using the techniques of the first aspect of the invention. By using the perforated moulding in place of moulding 14, and using an upper fabric sheet with a greater surface area than the lower fabric sheet, a layer or insert with natural curvature can be obtained. The moulding fixed to a sheet may be used with adapted joiner films and upper and lower membranes so that the 3-d layer is fabricated in si tu, prior to the vacuum drawn bonding technique. Alternatively, the perforated moulding may be detachable from the sheet and tubes, so that the techniques of the first aspect can be carried out in an appropriate location. Subsequently, the moulding may be fixed to the bench and the vacuum drawing technique enacted. As another alternative, it may be preferable to form the 3-d shaped layers on a separate moulding, placing them onto the perforated moulding when they are formed. There will now be described an embodiment in accordance with a seventh aspect of the invention. Figure 12 shows an inner layer 120 of a glove formed in accordance with the first aspect of the invention, or by any previously known technique. The inner layer is placed over a moulding, and adhesive cups 121 are placed over the ends of the fingers on the layer 120, to form the structure shown at 120a. An outer layer 122 is then placed over the layer including the adhesive cups, and heat is applied in order to bond the outer layer to the inner layer. As before, the heat can be applied from an infra-red source, or alternatively via heating elements disposed within the mould. The adhesive cups are made from a thermoplastic material, and can be formed from molten adhesive in a dip process, or preformed from adhesive sheet materials. If a dip process is used, the moulding and inner layers themselves may be dipped into the molten adhesive. Alternatively, a second mould may be used for the dip process, with the cups being transferred onto the inner layer thereafter. The adhesive cups are preferably formed to be no deeper than the typical distance from the tip of a finger to the first joint of the finger. This is because the cups provide additional structural strength to the finished glove, and increase the rigidity of the finger. In order to maintain the flexibility in the fingers, it is important that the adhesive cups do not extend beyond the first joint. A typical distance would be 16mm to 19mm. The concept of adhesive cups can also be used to provide protective regions of the garment. For example, needle-proof gloves can be made by placing cups of needle-proof plastics or turtle skin over the adhesive cups. The outer layer can then be placed over the needle-proof cups and bonded thereto, either via additional adhesive cups or by other means. It is envisaged that open ended cups may be used as part of the above process. Cups of this type would enable greater sensitivity to be retained in the glove. Open ended protective regions and open-ended adhesive cups may be used in any combination with the described method. The above techniques are not limited to the manufacture of gloves. Other garments may be made using the adhesive cups over the protruding portions of an inner layer. In particular, the method is applicable to the formation of socks, and linings for boots and shoes. Figure 13 shows a boot lining 130 which is provided with first and second adhesive cups 131 and 132. The first adhesive cup is formed over the toe-cap region of the lining, and extends to a point not beyond the point of flexing on the foot. The second adhesive cup 132 is provided over the heel area. A second layer 134 may be placed over the first layer 130 and the adhesive cups 131 and 132. Alternatively, the layer 130 could be bonded directly to the inside of a boot. The layers bonded may be any type of fabric layer. For example, the inner layers 120, 130 may be comfort inserts, and the layers 122, 134 may be outermost layers of gloves or socks. Alternatively, the layers may be intermediate layers in a multilayered garment. The methods disclosed herein are suitable for manufacturing multilayer garments, incorporating fireproof, waterproof, or gas proof, comfort inserts, and outer cover layers. The adhesive cups provide a strong bond between two layers of material, without resorting to stitching. Further, by restricting the size of the adhesive cups so that they do not extend beyond the joint of the foot or finger, the garment remains flexible and functional. The garments have the added benefit that the adhesive cups can be used to provide extra protection for the fingertips, toes or heels of a person wearing the garment. It is evident that the embodiments of the first, fifth and seventh aspects may be combined in order to form a process which includes the steps of vacuum drawing a second insert towards a first insert and bonding the two together, and subsequently bonding an outer layer over the combined inserts via a number of adhesive cups. The assembly can take place on any suitable mouldings, and in particular the whole process can take place on the perforated moulding of figure 10. The final garment can be blown from the moulding by the application of pressure to the inside of the moulding. Figure 14 shows in plan view apparatus for joining sheets of material. Upon a backing plate 1 are laid the sheets of fabric 2,3 which are to be joined. Joining sheets and cover sheets not shown in Figure 1 may be added underneath, above and between the sheets as discussed below. The method of the present invention begins by forming a plurality of microscopic holes 5, through the sheets of material. In this illustration these holes are placed all the way up to the edge 4 of the sheets, however, they may readily be placed anywhere within a sheet of material. The microscopic holes are preferably made with a pulsed laser which can readily and automatically make such holes. In one example, a 5-lOmm strip of fabric is perforated with holes .004 inches (0.1mm) wide, spaced .008-.012 inches (0.2 to 0.3mm) apart in a regular grid using a pulsed laser and a numerically controlled coordinate table. Clearly, there is considerable scope for variation in the size and distribution of holes. Figure 15 shows a close-up of a region of Figure 14 showing how a plurality of holes can be laid out in an array. No restriction is envisaged on the layout of array. The array configuration, hole spacing hole size, laser type, power and pulse width will be selected depending on the method of manufacture, the particular materials and the particular configuration in which materials are to be joined. Figure 16a shows one configuration of the present invention. Two sheets of material 2 and 3 to be joined are laid flat, separated by a joining layer 6. The sheets of materials have had microholes made in them 5. The joiner film is made from a thermoplastic material. The assembly is then heated, melting the thermoplastic joiner film which then proceeds to flow out of the holes 5, forming the configuration shown in Figure 17. As shown in Figure 17, the plastic joining material can flow outwith the circumference of the holes forming a structure which behaves mechanically like a rivet. Therefore once it is cooled a mechanically strong bond is formed between sheets 2 and 3. Furthermore, as the thermoplastic joining material is continuous, an airtight seal can readily be produced. An alternative arrangement has the thermoplastic sheets placed so that they extend beyond the edges of the fabric sheets, and over lap at these points. When the joiner sheets are melted, they merge at the edges of the fabric to provide an continuous thermoplastic sheet around both fabric sheets. Numerous variations to this configuration are envisaged. For example, Figure 16b shows a configuration identical to that in Figure 16a, other than that top and bottom layers made from a non-stick material, are put in place to allow heating and machinery to come into close contact with the sheets to be joined, but without actually coming into direct contact with the thermoplastic joining film therefore becoming stuck. Figure 16c shows a configuration where the joining film is present not just between the sheets to be joined but above and below them as well, improving waterproofing. Figure 16d shows a configuration where the joining layer is above, below and between the sheets and there is also provided a non-stick coating layer 7 above and below. In another embodiment, the thermoplastic joining layer is not positioned between the sheets to be joined before heating. In this embodiment, the sheets to be joined are placed in contact and thermoplastic joining layers are placed around the sandwiched sheets. Heat is applied so that the thermoplastic joining layer remains molten sufficiently long to enable the thermoplastic joining layers to pass through the holes and join with each other and so set to form a solid bond when the heat source is removed. Indeed, in this configuration, the thermoplastic material may be applied to the join already molten. Heating may be by any of a number of means. It is particularly envisaged that RF heating techniques be used. Alternatively, any heating methods suitable for melting the joining layer can be used. In the example Figures, the holes are made before laying the sheets above and below the joining film. However, it will be clear to one skilled in the art that it would be possible to make the holes in si tu and melt the joining layer 6, in a single manufacturing step using an appropriately configured laser. In the present invention, the solidified thermoplastic joining layer functions like a very high density of small rivets. In the example of Figure 14, holes are made around a perimeter of two sheets of material in order to form bag suitable for use as an airbag. By allowing airbags to be made from smooth materials a substantial improvement in the safety of air bags will be achieved. The joining layer will serve to form an airtight bond as it will flow throughout the whole region of the join between the two sheets. This technique will allow the use of totally airtight materials such as PTFE in airbags. The joining layer may be shaped to correspond to the shape of the join between sheets Instead of using a laser, mechanical means might be used to make the plurality of microholes. For example, perforating members or fine ultrasound beams may be used to make the microholes. Figures 18 and 19 show a rotating wheel 10 with a plurality of teeth 11. An ultrasound horn 12 emits ultrasound onto a sheet of fabric which is interspersed between the horn 12 and wheel 10, leading to formation of microholes. The wheel 10 might be mechanically milled or may be electronically machined or etched in a fine pattern. Two sheets made of the same material may be joined to each other, alternatively composites may be made. For example, a silicon type coating might be joined to a rip stop woven material. Further modifications may be made within the scope of the invention herein intended.

Claims: Claims 1. A method for making a shaped object from sheets of synthetic material comprising the steps of: (c) placing a first sheet of material in proximity to a second sheet of material such that the edges of the first and second sheets of material correspond; and (d) sealing together the edges of said sheets of material; characterised in that a mould is disposed between the first and second sheets of material, the mould having an upper surface for contact with the first sheet of material and a lower surface for contact with the second sheet of material, the mould being shaped such that the surface areas of the upper and lower surfaces are different and also being shaped such that the first and second sheets of material are in contact where they are to be sealed together or are separated only by layers intended to be incorporated into the final seam. 2. The method of claim 1 wherein the first sheet of material is placed against the mould by laying a first edge of the first sheet of material along one side of the mould and subsequently pressing the rest of the first sheet of material against the mould progressively. 3. The method as claimed in claim 1 or claim 2, wherein a progressive tool is used to press said first sheet of material against the mould and the second sheet of material. 4. The method as claimed in any preceding claim, wherein vacuum draw-down is used to bring a sheet of material into contact with the mould. 5. The method as claimed in any preceding claim, wherein first and second sheets of material are separated where they are to be sealed together by a thermoplastic joining film. 6. The method as claimed in any preceding claim wherein the shaped object is selected from the group comprising gloves, boots, jackets and trousers. 7. A shaped object comprising two sheets of flexible material, the edges of which correspond, joined around part of their perimeter by a waterproof seal, wherein one sheet of flexible material is of greater surface area than the other sheet of material. 8. The shaped object as claimed in claim 7, wherein shape of the object is selected from the group comprising gloves, boots, jackets and trousers. 9. A method of making a composite garment comprising the steps of: - forming a laminate of a synthetic membrane and a fabric sheet, the synthetic membrane having an adhesive layer thereon; - joining edges of two fabric sheets or two parts of the same fabric sheet to each other around part of their perimeter so as to form an insert for a garment; (c) inverting said insert for a garment and placing said insert for a garment within an outer layer of a garment; (d) placing a shaped inner layer of a garment within said insert, said inner layer having an adhesive layer thereon; (e) lasting the inner layer and insert to the outer layer of a garment and applying heat thereto so as to melt the adhesive layers and form a composite garment. 10. The method as claimed in claim 9 wherein the edges of the two fabric sheets or two parts of the same fabric sheet are joined using a thermoplastic joining layer. 11. A method of making a composite garment, the method comprising the steps of: - forming a garment shaped fibrous layer around a mould, -placing a garment liner around said glove shaped fibrous layer, the garment liner having a surface in contact with the garment shaped fibrous layer, the surface having a thermally activated adhesive thereon; and - heat activating the thermally activated adhesive, thereby joining the garment liner to the garment shaped fibrous layer. 12. The method as claimed in claim 11 wherein the garment is placed within an outer garment layer. ■ 13. The method as claimed in claim 11 or claim 12 wherein the garment shaped fibrous layer is formed around a mould using the method as claimed in claim 1. 4. A method for forming a garment, the method comprising the steps of: - providing an outer surface of a first insert with an adhesi e; - placing the first insert over a moulding, said moulding having a hollow centre and perforations formed in a surface thereof; - placing a second insert over the first insert; - reducing the pressure within the moulding, thereby drawing the second insert towards the first insert, and; - bonding the first and second inserts together. 15. The method as claimed in claim 14, wherein the adhesive is scattercoated on the outer surface of the first insert. 16. A method for forming a garment, the method comprising the steps of: - placing a first insert over a moulding, said moulding having a hollow centre and perforations formed in a surface thereof; - providing an inner surface of a second insert with an adhesive; - placing the second insert over the first insert; - reducing the pressure within the moulding, thereby drawing the second insert towards the first insert, and; - bonding the first and second inserts together. 17. A method as claimed in claim 16 above wherein the adhesive may be scatter coated on the inner surface of the second insert. 18. A method as claimed in any of claims 14 to 17 wherein the adhesive is a thermoplastic. 19. The method as claimed in any of claims 14 to 17 wherein the method includes the additional step of heating the first and second inserts, subsequent to the step of drawing the inserts together. 20. The method as claimed in claim 19 wherein the heating is accomplished by applying Infra Red radiation to the inserts. 21. The method as claimed in claim 19 wherein the heat is applied to the inserts via the moulding. 22. A method of forming a garment, said method comprising the steps of: - placing a first insert over a moulding; - providing at least one protruding portion of the first insert with one or more adhesive cups; - placing a second insert over the first insert including the one or adhesive cups, and; - bonding the first and second inserts together. 23. A method as claimed in claim 22 wherein the garment formed is a glove. 24. A method as claimed in claim 22 or claim 23 wherein the moulding is hand-shaped and the protruding portions are digits of the glove. 25. A method as claimed in any of claims 22 to 24, wherein the adhesive cups are thimble-shaped. 26. A method as claimed in any of claims 22 to 25 wherein the adhesive cups extend to a distance no further than the first joint from the tip of a finger. 27. A method as claimed in claim 22 wherein the garment formed is a sock or a lining for a boot. 28. A method as claimed in any of claims 22 or claim 27 wherein the mould is in the shape of a foot, and the protruding portion is the toe-cap region. 29. A method as claimed in any of claims 22, 27, and 28 wherein the adhesive cups extend no further than the balls of the feet. 30. A method as claimed in any of claims 22 or 27 to 29 wherein adhesive cups are provided over a heel region. 31. A method as claimed in any of claims 22 to 30, wherein the adhesive cups are manufactured from molten adhesive by a dip process. 32. A method as claimed in any of claims 22 to 30 wherein the adhesive cups are pre-formed from a sheet adhesive. 33. A garment manufactured by the method of any of claims 14 to 32. 34. A method of joining sheet materials wherein two sheet materials have join regions to be joined to each other, the method comprising the steps of: - forming a plurality of holes in the join regions of two material sheets; - arranging said material sheets so that the join regions are in face to face contact with a thermoplastic joining layer which separates them; - applying heat to said join regions in such a way as to cause the thermoplastic joining layer to melt and flow through holes; and - allowing the thermoplastic joining layer to cool, forming a bond between the material sheets. 35. The method as claimed in claim 34, wherein the material sheets are siliconised materials. 36. The method as claimed in claim 34, wherein the material sheets are PTFE-containing materials. 37. The method as claimed in any of claims 34 to 36, wherein the plurality of holes may be formed using a pulsed laser. 38. The method as claimed in any of claims 34 to 36, wherein the plurality of holes may be formed using a perforating member. 39. The method as claimed in any of claims 34 to 38, wherein heat is applied to the region of material sheets which are to be joined by an RF source. 40 . The method as claimed in any of claims 34 to 39, wherein the material sheets are underlaid and overlaid with further thermoplastic joining layers. 41. The method as claimed in any of claims 34 to 40, wherein Covering layers are situated between the regions of material which are to be joined and a source of said heat . 42. A method of joining sheet materials wherein two sheet materials have join regions to be joined to each other, the method comprising the steps of: (a) forming a plurality of holes in the join regions of two material sheets; (b) arranging said material sheets so that the join regions are in face to face contact; and (c) applying a molten thermoplastic material to said join regions in such a way as to cause the molten thermoplastic material to melt and flow through holes; and (d) allowing the thermoplastic material to cool, forming a bond between the material sheets. 43. The method as claimed in claim 42, wherein the molten thermoplastic material consists of two thermoplastic sheets in face to face contact with the join regions so that the both join regions are sandwiched between the thermoplastic sheets, wherein said thermoplastic sheets are then melted. 44. An article comprising two or more sheets of material joined using the method of any of claims 34 to 43. 5. An airbag comprising two or more sheets of material joined using the method of any of claims 34 to 43.

Inventors: CLARK ROBERT, CLARK, ROBERT
Applicants: CLARK ROBERT, LITE LINER TECHNOLOGY EUROP LT, CLARK, ROBERT, LITE LINER TECHNOLOGY EUROPE LIMITED
Application year: 2001
Main classification: A41D1
IPC codes: A41D19, A41D27, A41H43, B29C51, B29C53, B29C65