Patent Application
20230220595
The invention relates to a method for manufacturing a product that is waterproof and provided with a cavity, such as a glove, a shoe, a sports shoe or a backpack.
Cavity is understood to be a hollow space open on one side that, for example, there is in a glove or a sports shoe to insert a hand or a foot, and an inner hollow space of a backpack to accommodate the objects that the user wants to store therein, which can be accessed for example by opening a zipper or lifting a flap.
The invention also relates to a product that can be obtained from said method and to a system for carrying out said method.
In the fashion sector, and particularly in sportswear, the existence of products such as gloves, footwear and backpacks that are waterproof, and optionally also windproof and breathable (permeable to water vapour), is well-known.
Most of these products are produced by first making an outer structure of the product in a leather material or similar, textile material, or a combination thereof, which is not waterproof, by stitching several portions of the material connected by conventional needle and thread stitching together.
Subsequently, a pre-constructed inner mould, lining or form is arranged, produced from a waterproof and breathable membrane material. This inner mould, lining or form is introduced and fixed inside the outer structure to deliver waterproofness to the product. In some cases, this inner mould, lining or form is partially or completely attached to the interior of the outer structure by means of a discontinuous adhesive layer of thermoplastic applied to the outer surface of the inner mould, lining or form, which then melts under pressure and temperature and is attached to the inner surface of the outer structure.
Thus, it is usual for waterproof and breathable gloves and footwear to be manufactured in the indicated manner by stitching together portions of leather or textile materials, thus generating a series of seams between the portions. For example, to manufacture the outer structure of a glove, two portions are cut in the shape of a hand template, one portion for the face that will cover the palm and another portion for the face that will cover the knuckles, with attachment seams along the length of the perimeter, including the space between the fingers. The joint seams between portions comprise a series of stitches that inevitably leave holes as the stitch thread passes, so that the articles or products, if they are not sealed, are no longer waterproof and windproof at the seams.
However, at present it is not possible to seal these seams using sealing methods used for conventional products or articles of this type due to the fact that the radius of the seam and the dimension of the seams are generally too small for feasible manufacture. Thus, it would be desirable to provide a method for performing this sealing and thus obtaining products or articles provided with a cavity such as gloves, footwear and backpacks completely waterproof and that were compatible with the option that the products were breathable and windproof.
The object of the invention provides a method for manufacturing a product or article that is waterproof and provided with a cavity (open or closed but accessible) such as a glove, a shoe or a backpack.
The method object of the invention is characterised by firstly preparing a structure with the shape and outer surface of the product to be manufactured, attaching portions of laminated material such as laminated natural or synthetic leather, or a laminated material based on leather, a laminated textile material, or a laminated substrate, using conventional stitching methods, creating seams provided with stitches at the edges for attachment between the portions. On this structure a waterproof and windproof sealing is performed following the rest of the steps of the method.
As a clarification, it is noted that a laminated leather is a tanned leather to which a plastic sheet or membrane is adhered to the grain of the leather (the upper portion) with heat and pressure, achieving uniformity on the entire surface of the leather. A laminated textile material is that formed by a fabric to which a plastic sheet or membrane is adhered, on the unseen face thereof. Both laminated leather and laminated textile or laminated substrate are materials that are waterproof, and in many cases they can also be windproof and breathable.
Among the laminated materials that are envisaged, it is worth mentioning that the laminated (natural or synthetic) leather materials or those based on leather include laminated natural leather, laminated synthetic leather, and other types of laminated materials similar to laminated leather, such as bicast leather or reconstituted leather materials. Bicast leather laminate is made of solid pieces of leather that are given an artificial coating and subsequently the plastic sheet or membrane is added. In contrast, reconstituted leather ones, also called consolidated leather or mixed leather, comprise a layered structure of a paper fibre or support covered with a layer of shredded leather fibres mixed with a polyurethane binder that is embossed with a texture similar to leather. Reconstituted leather is also referred to as engineering leather by some manufacturers, as it is an advanced material made with up to 50% traditional leather fibres, which retains the appearance of traditional leather but is endowed with greater resistance to scratches, scuffs and has controlled stretch, enabling it to maintain the initially given shape thereof, according to specific manufacturing methods.
Laminated textiles and laminated substrates can be formed, in the structure that is attached to the plastic sheet or membrane, by natural or synthetic fibres, woven or non-woven, and the laminated substrates can also have a synthetic matrix on which fibres of synthetic natural origin are arranged.
In accordance with the method of the invention, once the structure has been created, a thermally-curable silicone compound material, also known as crosslinking silicone, is subsequently applied to the seams, preferably with the aid of a paintbrush or a brush, while this silicone compound is in an uncured liquid state. By spreading the thermally-curable silicone compound on the seams, including the edges or ends of the portions that face to form the seam, some of the compound remains on the stitches generated by stitching the portions.
Stitch is understood to be each one of the holes made with a needle, awl or other similar instrument, in the fabric, leather or other material that is being stitched. It should be mentioned that the seams themselves, where the edges of the portions are attached, are on the inner face or surface of the structure of the product or article, that which is not seen from the outside when the user normally uses it. Therefore, in order to apply the thermally-curable silicone compound, the outer structure has to be turned inside-out in order to apply it well to all seams.
Then, once the silicone compound has been applied to the seams, the structure is arranged inside a chamber or oven and subjected to a curing temperature of the silicone compound material, preferably comprised between 115° C. and 150° C., for a period also preferably between 2 and 30 minutes, and more preferably between 5 and 20 minutes, to cure the silicone compound. The curing temperature and time will depend on the features of the thermally-curable silicone compound. For example, there are silicone compounds that cure at 150° C. in 30 minutes and others that when cured at 150° C., do so in just 10 minutes.
Simultaneously at the beginning of the heating, a vacuum is also performed by sucking the air from the chamber or oven that is outside the structure into the structure (towards the cavity thereof) through the seams thereof, and from there said air is extracted outside, specifically out of the chamber or oven wherein the structure is located turned inside out. This is carried out by means of pumping means and this vacuum operation causes the curable silicone compound, in liquid state, to enter and penetrate into the seam stitch holes of the structure.
Once the compound is fully cured by means of heating to the curing or crosslinking temperature, the orifices or holes of the stitches are filled with a soft and flexible silicone gel, but very dimensionally stable with temperature. The silicone gel penetrates at least a depth from the beginning of the hole equivalent to 30% of the total depth of the hole (total thickness that crosses the stitch) when a vacuum is performed. The beginning of the hole (hole in the inner surface of the stitched structure) is where the compound is applied in liquid state, having turned the structure inside out, leaving on the outside the surface that corresponds to the inner surface of the stitched structure of the product in its normal use, and leaving on the inside the outer surface of the outer structure of the product (glove, shoe, backpack, etc.), and by the action of the vacuum to which the structure is subjected inside the chamber or oven, the silicone compound material goes into the holes of the stitches until they are plugged, and the same happens in the spaces that may exist in the seam between the edges of two stitched portions.
It should be noted that, preferably, the simultaneous application of temperature and vacuum by extraction of air on the turned inside out structure is performed, as has been said, in an oven or chamber, but specifically, in said oven or chamber the structure is arranged fitted with a certain tightness on a hollow inner mould or skeleton the outer surface of which reproduces the inner shape of the structure.
The hollow inner mould or skeleton is provided with a plurality of vacuum openings that communicate the outside of the inner mould or skeleton with the inner cavity thereof, the vacuum openings being crossed by the air from outside the structure (the air from inside the chamber or oven) that is sucked into the structure when a vacuum is performed. The vacuum openings of the inner mould or skeleton may be configured as through holes, as meshes of a net from which the inner mould or skeleton is made, or as elongated slits. Meshes are understood to be the quadrilaterals or polygons formed by ropes, threads or wires that intersect and are knotted at the apexes thereof, which constitute a network.
The hollow inner mould can be formed by a metal frame provided with holes or slits, or by a structure of wire or threads that form a mesh network. Alternatively, it can be formed by a body generated with a 3D printer in which the slits, meshes or holes that form the vacuum openings are already generated, for example, said body being able to be made of a plastic material resistant to the curing temperature of the silicone compound material so that the shape thereof remains stable despite heating.
Thus, in the oven or chamber, the heated air that externally surrounds the inner mould or skeleton is sucked by pumping means into the inner hollow of the mould to then expel it out of the oven or chamber, thus creating a vacuum inside the inner mould or skeleton. As the stitched structure is turned inside out on the inner mould or skeleton, the hot air sucked in through the vacuum openings of the inner mould or skeleton is also introduced through the stitch holes of the seams of the structure inside the mould and thus the silicone compound material is also introduced into the stitch holes and in the spaces that remain in the seams between the edges of the stitched portions. The ideal situation is that a moment is reached when no more air it is able to be pulled inside, which will indicate that the stitch holes and the spaces between portions of the seams are completely blocked by the silicone gel.
The inner mould or skeleton, in addition to enabling the creation of a vacuum within the inside out turned structure, also serves as a support for said turned structure when the thermally-curable silicone compound, in liquid state, is applied to it with a paintbrush or a brush, on all the seams (including all stitches and gaps between the edges of two stitched portions). The compound must be applied in all the meeting points between facing portions of laminated material (leather or similar, textile or substrate) from which the stitched structure is made, in addition to in all the stitches of the seams, to guarantee correct sealing once the process is finished.
The temperature causes the silicone compound material to cure and acquire the solid and flexible state thereof, and the vacuum causes said material to fill the stitch holes to a great extent, entering to a depth of at least 30% of the total depth or length of each hole (equivalent to the thickness of the portion or portions of the laminated material), while it is curing, so that the stitched structure is sealed at the seams thereof.
Finally, the structure already sealed at the seams thereof is removed, it is turned the right way round and it can already be said that the outer structure of the product is waterproof, without visually appreciating the sealing performed so that the aesthetics of the product is not seen affected. If the material of the stitched portions of laminated material was windproof and breathable, the structure sealed at the seams thereof will continue to be so, since the method does not affect these intrinsic features of the material used for manufacturing the product. Depending on the design of the final product, the necessary finishing operations will be performed on the structure, such as putting a soft inner lining, a rubber or closure on the wrist portion (in the case of a glove), etc.
In addition to the method of the invention described above, a second aspect of the invention consists of a product that is waterproof and provided with a cavity, such as a glove, a shoe, a sports shoe or a backpack, characterised in that the product is made of portions of laminated material such as laminated natural or synthetic leather, and/or a laminated material based on leather, and/or a laminated textile material, and/or a laminated substrate, and in that it can be obtained by the method described above. The obtainable product exhibits the sealing of the seams of the outer structure that is part of the product.
According to a feature of the product object of the invention, the seam stitch holes of the product (the seams of the outer structure thereof) are partially or completely filled with a thermally-cured silicone compound, with a filling depth of at least 30% of the sum of the thicknesses of the portions of laminated material attached at the seam. It is possible to plug the holes of the stitches and the spaces between the edges of the portions that form the seams with higher percentages of occupation of the hole, being able to plug 50% of the depth of the hole of a stitch and even achieve that the entire hole of the stitch is filled with cured silicone gel.
According to a third aspect of the invention, a system for manufacturing a product that is waterproof and provided with a cavity, such as a glove, a shoe, a sports shoe or a backpack, is also disclosed, wherein the product comprises a structure with the shape and outer surface of the product, provided with a cavity, the structure being made up of portions of laminated material such as laminated natural or synthetic leather, and/or a laminated material based on leather, and/or a laminated textile material, and/or a laminated substrate, the portions being stitched and attached together by corresponding seams.
The system object of the invention is characterised in that it comprises:
at least one hollow inner mould or skeleton the outer surface of which reproduces the inner shape of the structure of the product, the inner mould or skeleton being provided with a plurality of vacuum openings that communicate the outside of the inner mould or skeleton with the cavity thereof;
a chamber or an oven with room to arrange inside the at least one hollow inner mould or skeleton, provided with heating means, and
pumping means to create the vacuum inside the inner mould or skeleton, capable of being activated when the at least one hollow inner mould or skeleton is arranged inside the chamber or oven, sucking the air from outside the inner mould or skeleton into the cavity thereof through the vacuum openings and extracting said sucked air out of the cavity and the chamber or oven.
In a first embodiment, the system object of the invention comprises a chamber or oven inside of which one or more hollow inner moulds or skeletons are arranged.
In a second embodiment, the system object of the invention is characterised in that it comprises a plurality of hollow inner moulds or skeletons arranged on a conveyor belt, band or strap in which each hollow inner mould or skeleton is connected to respective pumping means suitable for creating a vacuum inside the respective inner mould or skeleton, and in that the chamber or oven extends longitudinally in the direction of advance of the conveyor belt, band or strap and is configured with two ends provided with means to enable the inlet and outlet of a group of the plurality of inner moulds or skeletons to/from the chamber or oven.
The attached drawings illustrate, by way of non-limiting example, portions of the stitched structure from which a product provided with a cavity, such as a glove, is manufactured according to the method object of the invention, as well as two embodiments of the system for manufacturing the product. In said drawings:
Laminated leather is a tanned leather to which a plastic sheet or membrane 22 is adhered to the grain of the leather 21 (the upper portion) with heat and pressure, achieving uniformity on the entire surface of the leather. Similarly, a laminated textile material is that formed by a fabric (which would be comparable to the grain of the leather 21) to which a plastic sheet or membrane 22 adheres, on the non-visible face thereof. Laminated leather and laminated textile material are waterproof materials, and in many cases they are also windproof and breathable (permeable to water vapour), so it is very advantageous to manufacture products or articles from them such as gloves, shoes, sports shoes (for example, for sports practice), boots or backpacks so that these products also exhibit these properties.
The portions 2 are intended to be made of any one of the following laminated materials: laminated leathers or leather-based laminates, including laminated natural leathers, laminated synthetic leathers, and other types of laminated materials similar to laminated leather, such as bicast leather or reconstituted leather materials; laminated textile materials and laminated substrates, the structure that is attached to the plastic sheet or membrane being able to be formed by natural or synthetic fibres, woven or non-woven, and the laminated substrates being able to further exhibit a synthetic matrix on which fibres of synthetic natural origin are arranged.
To carry out the manufacture of these products, first a structure 10 is made with the shape of the product by stitching portions 2 of laminated material attached together by corresponding seams 3, that is, joining the portions 2, facing them or partially overlapping them and stitching them together so that they stay together.
This structure 10 is the part of the product that will remain on the outside once finished, with the shape and surface thereof, that is, as an outer structure of the glove, shoe, or backpack that is manufactured. When joining the portions 2 by means of seams 3, it must be taken into account that when passing the thread that holds the portions 2 together, the needle or tool creates stitches 4 in the portions 2 of laminated material. These stitches 4 are the holes through which the thread passes but which at the same time represent a path for the inlet of water, wind and water vapour, so if they are not properly sealed, the product being manufactured will no longer be waterproof. The same happens with the edges 31 of the facing or overlapping portions 2 that form the seams 3, since it is also necessary to seal them.
A dashed line in
In order to carry out the correct sealing of the stitches 4 and of the edges 31 of the seams 3, the stitched structure 10 with the shape of the product and formed by a plurality of portions 2 attached by seams, is turned inside out.
The portion of structure 10 shown in
To apply the thermally-curable silicone compound material, in uncured liquid state 5, on the seams 3, the structure 10 turned inside out is fitted tightly on a hollow inner mould or skeleton 7 the outer surface of which reproduces the inner shape of the product (particularly, the inner shape of the structure 10), such as those shown in
The hollow inner mould or skeleton 7, which can be metallic or made of a plastic material resistant to the curing temperature of the silicone compound material, is provided with vacuum openings, configured as through holes 71 in
After applying the thermally-curable silicone compound material, in uncured liquid state 5, the structure 10 is simultaneously subjected to a heating operation at a curing temperature of said silicone compound material and to a vacuum operation. The vacuum operation consists of sucking the air from outside the structure 10 into the structure 10 by means of pumping means 9 and subsequently extracting it from the inside out, as shown in
What is achieved with the simultaneous heating and vacuum operations is that as the silicone compound material, initially in uncured liquid state 5, cures, becoming a silicone gel that is soft and flexible but very dimensionally stable with temperature, the silicone compound material enters and penetrates the holes of the stitches 4 of the seams 3 by the vacuum created, by which the silicone compound material is pushed by the air outside the stitched structure into the holes of the stitches 4. By creating the vacuum in the chamber or oven 8, in which the structure 10 with applications is located, air is extracted from inside this structure 10 with applications; in fact, air is extracted from inside the inner mould 7 which causes the curable silicone compound, in uncured liquid state 5, to enter and penetrate the holes of the stitches 4 of the seams 3.
With the pumping means 9, the air from the chamber or oven 8 that is outside the structure 10 of the product is sucked in and directed towards the cavity of the hollow inner mould or skeleton 7. The through holes 71, the meshes 72 or the slits 73 of the hollow inner mould 7 lead the air from inside the chamber or oven 8 into the inner mould 7 and from there it is extracted out of the oven 8 or chamber, so that the liquid silicone compound is initially introduced, by effect of the vacuum created, through the stitches 4 and spaces between the meeting points of the laminated portions 2.
The curing temperature and time will depend on the features of the thermally-curable silicone compound. For example, there are silicone compound that cure at 150° C. in 30 minutes and others that when cured at 150° C., do so in just 10 minutes. In most cases, the temperature in the chamber or oven 8 will be comprised between 115 and 150° C. and the curing will take between 2 and 30 min.
Once the silicone compound is fully cured by heating to the curing or crosslinking temperature, the orifices or holes of the stitches 4 are filled with a silicone gel 6 that is soft and flexible, but very dimensionally stable as mentioned above. The silicone gel 6 has penetrated at least to a depth from the beginning of the hole equivalent to 30% of the total depth of the hole (depth is the total thickness that crosses the stitch 4) when a vacuum is created. Thus,
In this way, the structure 10 of stitched portions 2 is already entirely a waterproof structure, since the seams 3 have been perfectly sealed with the silicone gel 6. To finish making the product, the structure 10 will be removed from the inner mould or skeleton 7, it will be turned the right way round to put the structure of stitched portions with the sealed seams 3 the right way round and the finishing operations that are required will be carried out, such as putting a soft inner lining, a rubber or closure on the wrist portion, etc.
The system comprises one or more hollow inner moulds or skeletons 7 as those explained above, provided with through holes 71 or meshes 72 that cross it and communicate the outside of the hollow inner mould or skeleton 7 with the cavity thereof; pumping means 9 to create the vacuum inside each inner mould or skeleton 7; and a chamber or an oven 8 with room to arrange inside one or more hollow inner moulds or skeletons 7, the oven 8 having heating means 81 to reach the curing temperature of the silicone compound material initially in uncured liquid state 5.
| Number | Date | Country | Kind |
|---|---|---|---|
| P202030596 | Jun 2020 | ES | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/ES2021/070439 | 6/15/2021 | WO |
