Method for manufacturing an article of footwear

Abstract

The subject of the present invention is a method for manufacturing an article of footwear, the method comprising: manufacturing and providing a first knitted tubular portion (20) comprising at least one fusible portion, and one or more functional components (60; 70; 75); then, forming a footwear component (40) comprising the first knitted tubular portion (20) and the one or more functional components (60; 70; 75), and transforming the footwear component (40) arranged on a preform having a foot shape (50) into an upper (400), the transformation step comprising the step of at least partially thermoforming and fixing the one or more functional components (60; 70; 75) to the first knitted tubular portion (20), the thermoforming and fixing steps being performed in a single step, the single step comprising placing the footwear component (40) under vacuum.

Description

Field of the Invention

[0001] The subject matter of the present invention is a method for manufacturing an article of footwear, in particular an article of footwear for practicing a sport.

[0002] The subject matter of the present invention is a method for manufacturing an article of footwear that implements one or more three-dimensional tubular knitting assemblies for producing an upper including an integral sole portion. Background Art

[0003] Articles of footwear of the prior art typically include two main elements, namely an upper and a sole structure. The upper is fixed to the sole structure and forms an empty space or volume for receiving the foot within the article of footwear to safely and comfortably receive the foot. The sole structure is fixed to the lower region of the upper and is thus positioned between the upper and the ground.

[0004] In an article of footwear (such as for practicing a sport), the sole structure may include a midsole and an outsole, the outer surface of the outsole being intended to come into direct contact with the ground.

[0005] The midsole generally includes a material made of polymeric foam that attenuates the impact response with the ground to reduce the impact resilience exerted on the foot and leg during walking, running or other activities while wearing the article of footwear.

[0006] Furthermore, the midsole may include one or more fluid-filled chambers, one or more shock-absorbing portions or other elements that can attenuate the impact resilience and improve stability, which would otherwise affect the movement of the foot and thus the grip.

[0007] The wear-resistant sole is fixed to the lower surface of the midsole and provides a portion for engaging the sole structure with the ground, the ground-engaging portion being formed of a wear-resistant and durable material, such as for example rubber or synthetic elastomer. The sole structure may also include a lining that is positioned within the foot-receiving volume of the upper and adjacent to the lower surface of the foot to enhance the comfort of the article of footwear.

[0008] The upper generally includes a number of pieces, such as an outer quarter, an inner quarter, a front protective cap, a tongue, a heel, a heel support, a vamp, a tightening device with in particular holes / (eyelets for passing the shoelaces) and shoelaces, a lining and optionally other parts. Some of these pieces may be made of several parts. Thus, the manufacture of the shoe requires assembling these different pieces to form a three-dimensional upper by cutting out these pieces and assembling them flat.

[0009] The upper generally extends along the outer and inner sides of the foot and around the ankle region above the arch of the foot and in the region of the toes.

[0010] In certain applications, such as basketball or, for example, hiking, the upper can extend upward and around the ankle to provide support and additional protection for the ankle. Tightening devices are often incorporated into the upper to adjust the size of the upper, thereby allowing the foot to enter and exit the empty space formed within the upper. The upper can also include a tongue that extends beneath the tightening device, such as a lacing system, to adjust the footwear item, and the upper can include a rear reinforcement element that restricts heel movement. The assembly of these different components / elements / blocks requires a significant amount of time and can lead to errors in the manufacture of the footwear item. As a result, the potential number of errors can be large, complicating the manufacturing process and thus making it more costly.

[0011] Once formed, the upper is thus given volume, in particular by being assembled, for example using seams, at the height of the heel, and the upper is associated in a known manner with a sole element, in particular a sole element that enters into the sole structure, to define the volume of the footwear.

[0012] Thus, the upper can be bonded to the sole element by an adhesive layer; it can be bonded to a relatively rigid insole.

[0013] Alternatively, by shaping the upper using different seams and then assembling the upper to the insole by stitching according to the so-called Strobel technique, the upper can be assembled to the sole element. In this case, the insole is generally soft so that it can be stitched. Thus, the insole forms the sole part or bottom of the upper.

[0014] The time and cost associated with transporting, storing, cutting, and assembling the different parts are significant. In addition, a large amount of waste is generated when cutting and assembling the parts. Footwear items having a large number of components made of different materials are more difficult to recycle because separating the components to recycle them is particularly complex. Thus, by reducing the number of different components in the composition that goes into the shoe, the amount of waste can be reduced, and the efficiency of the method for manufacturing such footwear items as well as the recyclability of the upper can be increased.

[0015] Thus, provisions have been made for the production of footwear items that implement an upper obtained from the manufacture of a three-dimensional knitted tube. These methods first achieve the knitting of an insole upper by knitting a tubular knitted component that is substantially sock-shaped.

[0016] Then, the method includes creating a longitudinal incision in the sole portion of the knitted tubular component and then using this longitudinal incision to lay the knitted tubular component flat to expose an outer surface on which one or more functional components can be laid flat. These functional components, such as logos, reinforcement elements, lace eyelets, hard caps, or vamp or heel reinforcements, are applied to the flat outer surface of the knitted tubular portion and then fixed to each other, for example, by adhesion and / or stitching. Fixing can be carried out by adhesion, for example, manually using an iron. Then the longitudinal incision made in the sole portion is closed, for example, using a seam. Then a footwear component is obtained that includes an insole upper fixed to one or more functional components. The footwear component is placed on a foot-shaped preform and then thermoformed to the foot shape of the preform to form the final upper. Since the size of the preform corresponds to a given foot size, many preforms are required. The preform is made of plastic or composite material. Finally, a sole element such as a midsole is fixed to the sole portion of the upper.

[0017] Creating a longitudinal incision in the sole portion of the knitted tubular portion to lay the knitted tubular portion flat and enable its functionality requires additional steps. In addition, the fact of fixing functional components to the knitted tube arranged in a plane only allows for functionalizing a small area of the knitted tubular component. Despite the longitudinal opening, it is not possible to lay the entire knitted tube flat. Therefore, it is not possible to functionallyize the entire surface of the upper in three dimensions. Moreover, the functional components added during functionalization when flat may be thermally damaged during the next thermoforming process, further restricting the size and / or nature of the functional components that can be used.

[0018] Therefore, there is a need for a method for manufacturing footwear items that enables three-dimensional access to the entire footwear component - intended to form the upper - during its functionalization, without being limited by the size and number of one or more accessible functional areas.

[0019] There is also a need for a method for manufacturing footwear items that limits the number of assembly steps without damaging the implemented functional components.

[0020] There is also a need for a manufacturing method that can shorten the manufacturing time and improve the quality of the obtained upper. Summary of the Invention

[0021] The subject matter of the present invention is a method for manufacturing footwear items that limits the number of components and / or pieces, thereby enabling a significant reduction in manufacturing time, the number of manufacturing steps, limiting assembly errors, and minimizing the amount of waste.

[0022] The subject matter of the present invention is also a method that provides more possibilities in the aesthetic design of the upper and can improve the stability of the upper.

[0023] Accordingly, the subject of the present invention is a method for manufacturing an article of footwear that alleviates the above problems, which comprises the following steps:

[0024] (i) - providing a first knitted tubular part comprising one or more fusible parts, and one or more functional components;

[0025] (ii) - forming a footwear assembly comprising the first knitted tubular part and one or more functional components;

[0026] (iii) - transforming the footwear assembly disposed on a preform having a foot shape into an upper; the transformation step comprising:

[0027] - thermoforming the footwear assembly to follow the foot shape of the preform, and

[0028] - at least partially fixing one or more functional components to the first knitted tubular part.

[0029] Furthermore, the thermoforming and the fixing are carried out in a single step, which single step comprises placing the footwear assembly in a vacuum.

[0030] Advantageously, one or more functional components are fixed to the first knitted tubular part while thermoforming, which can in particular dispense with the steps of cutting into the sole part, flattening, closing the cut, and fixing one or more functional components before the thermoforming step.

[0031] Advantageously, the footwear assembly is placed against the outer surface of the preform.

[0032] Preferably, one or more functional components are disposed on the first knitted tubular part arranged in a three-dimensional manner according to the foot shape, in particular on a preform having a foot shape, in particular on the preform used during the transformation step (iii). Such an arrangement provides more possibilities for personalizing and stabilizing the first knitted tubular part, especially since the entire outer and inner surfaces thereof are fully available.

[0033] During step (ii), one or more functional components may be kept disposed on the first knitted tubular portion and / or the second knitted tubular portion by means of: stitching and / or gluing and / or by fusing, in particular hot fusing, in particular by ultrasound, for example using one or more holding points; in particular by means of one or more seams and / or one or more adhesive points and / or one or more fusion points, such as ultrasound fusion. This arrangement makes it possible to retain the functional components in their functionalized positions. Furthermore, during step (iii), the thermoforming and fixing steps are carried out simultaneously, in particular by applying heat and vacuum placement, optionally in combination with one or more gas flows, in particular water vapour, such that it is possible to avoid carrying out thermoforming on a footwear component that may have undergone heat treatment during functionalization when flat, thereby avoiding damaging the functional components and the first knitted tubular portion.

[0034] Advantageously, the vacuum placement makes it possible to press the footwear component flat against the preform, and the footwear component is held against the preform by suction. Preferably, the vacuum placement is carried out in the moulding volume that receives the footwear component. The moulding volume may be formed between a foot-shaped preform and a back mould (in particular rigid, for example made of multiple parts) or a flexible film, which then follows the shape of the preform (covered by the footwear component).

[0035] The flexible film may be made of a flexible and deformable material, for example made of silicone or polyurethane. By definition, the film is airtight.

[0036] The vacuum placement may also improve the aesthetic appearance of the upper, as well as the mechanical characteristics of the upper. It also makes it possible to fix one or more functional components in the form of a film in a completely regular manner and to fix them well to the textile tubular portion, in particular in order to cover the extended outer surface of the footwear component in order to provide a continuous or discontinuous outer coating.

[0037] The transformation step (iii) by providing heat makes it possible to melt / soften one or more fusible portions. The footwear component is also compressed and pressed flat against the outer surface of the preform. After the footwear component has cooled, in particular at ambient temperature, the footwear component is held against the outer surface of the preform under pressure, and subsequently, the footwear component finally retains the foot shape of the preform. The melting or softening, followed by cooling, of one or more fusible portions makes it possible to impart the foot shape of the preform to the footwear component and optionally to fix one or more functional components to the first tubular portion.

[0038] By definition, thermoforming involves applying heat to a footwear component, and this is done at a sufficient time and temperature to thermoform the footwear component into the shape of a preform foot. Preferably, the temperature applied is greater than or equal to the melting and / or softening temperature of one or more of the first knitted tubular part and / or the second knitted tubular part.

[0039] One or more functional components can be fixed by means of one or more fusible parts included in one or more of the first knitted tubular part and the second knitted tubular part, and / or one or more fusible parts included in the one or more functional components themselves, and / or one or more, in particular at least partially fusible, adhesive means. In the last case, the one or more adhesive means are considered equivalent to one or more functional components having an intermediate fixing function according to the invention.

[0040] One or more functional components according to the invention have at least one function selected from the following functions: shock absorption, reinforcement, adhesion, continuous or discontinuous protective coating, aesthetic appearance, or a combination thereof.

[0041] The first knitted tubular part and / or the second knitted tubular part (defined hereinafter) can be knitted on a double-needle straight-bar knitting machine or a circular knitting machine.

[0042] The step of transforming (iii) a footwear article into an upper includes: simultaneously performing the fixing of one or more functional components, and optionally performing the fixing of the first tubular part and the second tubular part knitted to each other, and thermoforming.

[0043] Preferably, each of the first knitted tubular part and / or the second knitted tubular part is an envelope that includes a sole part (intended to be located under the wearer's foot), an outer part (intended to contact the outer side of the wearer's foot), an inner part (intended to contact the inner side of the wearer's foot), a front part in the extension of the inner part, the outer part and the sole part (intended to cover the front of the foot), and a back part in the extension of the inner part, the outer part and the sole part (intended to cover the back of the foot, and thus cover the heel, and optionally cover the ankle). The envelope can be arranged to cover all or part of the ankle and optionally extend over the ankle.

[0044] The front part of the envelope can include a tongue and a distal pocket intended to receive the toes. The tongue can form a single part with the front part only along the front edge of the tongue, or in addition to the front edge of the tongue, the tongue can be fixed to the front part along its outer edge and inner edge respectively together with the outer part and the inner part.

[0045] The back part can include a pocket configured to receive the heel.

[0046] The envelope preferably defines a volume or empty space intended to accommodate the foot of the wearer.

[0047] In one embodiment, the first knitted tubular part and the knitted envelope have an integral knitted structure such that the envelope and the first knitted tubular part comprise a single knitted piece.

[0048] In one embodiment, the second knitted tubular part and the knitted envelope have an integral knitted structure such that the envelope and the second knitted tubular part are made of a single knitted piece. In this case, the knitted piece forming the second knitted tubular part and the knitted piece forming the first knitted tubular part are fixed to each other, especially during the conversion step (iii), for example by stitching.

[0049] In another embodiment, the first knitted tubular part and the second knitted tubular part are respectively located in an envelope, and the two envelopes respectively have an integral knitted structure with their first knitted tubular part and second knitted tubular part, and the two envelopes have an integral knitted structure with each other, and thus comprise a single knitted piece.

[0050] The first knitted tubular part and / or the second knitted tubular part comprises one or more yarns, especially mechanically assembled by knitting.

[0051] One or more yarns can be independently selected from: one or more monofilament yarns, one or more fibrils, one or more multifilament yarns and combinations thereof.

[0052] The yarn can be a non-meltable yarn, at least partially meltable yarn or completely meltable yarn, or a mixture thereof.

[0053] Thus, the first knitted tubular part and / or the second knitted tubular part (each) comprises one or more at least partially meltable yarns and / or one or more non-meltable yarns.

[0054] By definition, thermoforming involves applying heat to the footwear assembly, and this is done for a sufficient time and at a sufficient temperature to thermoform the footwear assembly into the shape of a prefabricated foot. Preferably, the applied temperature is greater than or equal to the melting and / or softening temperature of one or more thermoformable parts of the first knitted tubular part and / or the second knitted tubular part.

[0055] In transformation step (iii), by providing heat, one or more fusible portions can be melted / softened, and the footwear assembly is also compressed and pressed flat against the outer surface of the preform. After the footwear assembly cools, particularly to ambient temperature, the footwear assembly is held against the outer surface of the preform under pressure, and the footwear assembly then finally retains the foot shape of the preform. The melting or softening of one or more fusible portions, followed by cooling, enables the foot shape of the preform to be imparted to the footwear assembly and, at the same time, fixes one or more functional components to the first tubular portion.

[0056] The duration of step (iii), particularly thermoforming, can be greater than 0 seconds and less than or equal to 30 minutes, particularly less than or equal to 5 minutes.

[0057] Thus, the footwear assembly can comprise one or more materials that are capable of melting upon the application of heat but are not activated during step (iii). Such material or materials are considered non-fusible herein.

[0058] The fusible yarn, particularly at least partially fusible yarn, can be a yarn comprising at least two components, particularly a bicomponent type of yarn, wherein the first component has a melting temperature less than or equal to one or more heating temperatures employed in step (iii), and the second component has a given melting or degradation temperature greater than one or more heating temperatures employed in step (iii).

[0059] The fusible yarn can be a single-component yarn having a melting temperature less than or equal to one or more heating temperatures employed in step (iii).

[0060] The first component can be selected from: polyurethane, particularly thermoplastic polyurethane; polyamide, such as polyamide 6 or polyamide 6-6; polyolefin, such as polypropylene (PP) or polyethylene (PE); preferably selected from polyurethane.

[0061] The first component can be colored or colorless and / or opaque or transparent.

[0062] The second component can be selected from: polyolefin, such as high-density polyethylene; polyamide, such as polyamide 4-6, polyamide 6 or polyamide 6-6; polyester, such as polyethylene terephthalate.

[0063] The bicomponent material can be of the core-sheath type, with the core formed by the second component and the sheath formed by the first component.

[0064] Preferably, one or more heating temperatures applied to the footwear assembly during transformation step (iii) are greater than or equal to 80 °C, more preferably greater than or equal to 90 °C, preferably greater than or equal to 100 °C.

[0065] Preferably, one or more heating temperatures applied to the footwear component during transformation step (iii) are less than or equal to 250 °C, more preferably less than or equal to 200 °C, and preferably less than or equal to 180 °C.

[0066] Preferably, the melting or softening temperature of one or more fusible components is less than or equal to one or more heating temperatures.

[0067] One or more yarns, particularly non-fusible yarns, may comprise one or more materials which may be independently selected from synthetic materials, man-made materials (such as lyocell or viscose), natural materials, mineral materials or inorganic materials and combinations thereof, preferably selected from synthetic materials, man-made materials and natural materials, particularly synthetic materials.

[0068] One or more synthetic materials preferably include: polyesters, particularly polyethylene terephthalate (PET) and polybutylene terephthalate (PBT); polyamides (such as PA 6, PA 6-6, PA 12, PA 4-6); polyolefins (polypropylene, polyethylene, polyether ether ketone (PEEK), ultra-high molecular weight polyethylene (PEUHMW)); aromatic polyamides, particularly meta-aramid or para-aramid or mixtures thereof; vinyl acetate (such as EVA), polyacrylates (such as polyacrylonitrile); elastomers; elastic fibers, or mixtures thereof, preferably if they are polyesters and polyolefins.

[0069] One or more natural materials preferably include: cotton, viscose, linen, sisal, wool, jute, silk and hemp.

[0070] One or more mineral materials or inorganic materials preferably include: carbon, mineral fibers, such as minerals, such as rock wool, glass.

[0071] The diameter of the monofilament yarn is preferably greater than 0.01 mm and less than or equal to 5 mm, more preferably greater than or equal to 0.1 mm and less than or equal to 2 mm.

[0072] The fineness of the multifilament yarn and / or the fiber tow is preferably greater than or equal to 10 dtex and less than or equal to 1000 dtex, more preferably greater than or equal to 30 dtex and less than or equal to 500 dtex.

[0073] The multifilament yarn may be a textured yarn, FDY (fully drawn yarn), DTY (drawn textured yarn) or POY (partially oriented yarn), or a mixture thereof.

[0074] As used herein, the term "longitudinal" shall be understood to mean the direction extending along the length or long axis of the footwear article or the shoe upper. In some cases, the longitudinal direction may extend from the forefoot region to the hindfoot region of the footwear article or the shoe upper.

[0075] One or more first and second knitted tubular parts may also include one or more elastic yarns, in particular made of elastic fibres.

[0076] In the present context, the term "lateral" should be understood to mean the direction extending along the width or short axis of the footwear assembly or upper. Thus, the lateral direction may extend between the inner and outer sides of the footwear item.

[0077] In the present context, the term "vertical" should be understood to mean the direction extending substantially perpendicular to the lateral and longitudinal directions.

[0078] In the present context, the term "thermoforming" should be understood to mean the action of forming by heating the footwear assembly to the foot shape of the preform, i.e. by combining the melting of one or more fusible parts with the subsequent pressing of the footwear assembly flat against the foot shape of the preform, and then by cooling the footwear assembly having the foot shape of the preform, in particular to ambient temperature.

[0079] In one embodiment, step (iii) comprises providing a footwear assembly which has previously been provided on a foot-shaped preform in a moulded volume. The moulded volume is preferably defined by a mould comprising one or more parts, in particular two parts, in particular the outer surface of the preform.

[0080] The moulded volume may also be defined between an airtight and flexible film and the outer surface of the preform.

[0081] The moulded volume is substantially a foot shape complementary to the foot shape of the preform.

[0082] In a variant, during the transition step (iii), one or more gas flows, in particular water vapour, are applied to the footwear assembly in a single step in combination with heat.

[0083] Advantageously, one or more gas flows, in particular water vapour, may enable the heat to be better distributed over the footwear assembly, to make the footwear assembly more flexible, to better follow the shape of the preform and to prevent thermal degradation of the yarn. The water vapour may also allow the transformed textile parts to remain flexible and not have a stiff feel or sensation.

[0084] The combination of these parameters enables the footwear assembly to obtain very good fixation and perfect shaping to the foot shape of the preform. During thermoforming and fixation, one or more gas flows, in particular water vapour, are applied to the footwear assembly, in particular simultaneously.

[0085] A non-exhaustive explanation of these technical effects, without limiting the present invention, would be that water vapor would act as a plasticizer on the textile and / or polymer elements included in the footwear assembly, particularly the first knitted tubular part and / or the second knitted tubular part. In a variant, the method comprises providing a second knitted tubular part, which optionally includes at least one fusible part, and the footwear assembly in step (ii) includes a first knitted tubular part and a second knitted tubular part that are at least partially overlapping and connected to one or more functional components.

[0086] The provision of the second knitted tubular part enables the strengthening of the shoe upper and provides more functionality and stability to the shoe upper.

[0087] The first knitted tubular part can be the same as or different from the second knitted tubular part.

[0088] Preferably, when the footwear assembly is located on the preform, the second tubular part is arranged within the receiving volume of the first knitted tubular part. Of course, this can be reversed depending on the type of footwear item desired, and the first tubular part can be arranged within the receiving volume of the second knitted tubular part to form a footwear assembly arranged on the preform. In the latter case, the first knitted tubular part particularly at least partially forms the inner layer of the shoe upper.

[0089] Preferably, the second knitted tubular part includes an outer surface and an inner surface that are opposite each other, and the inner surface of the second tubular part at least partially covers the outer surface of the preform.

[0090] Preferably, the first knitted tubular part includes an outer surface and an inner surface that are opposite each other, and the inner surface of the first tubular part is arranged to at least partially abut against the outer surface of the second tubular part. Thus, the outer surface of the first knitted tubular part directly leads to the molding volume.

[0091] In a variant, the fixing in step (iii) allows at least partially:

[0092] - Fix the first knitted tubular part and the second knitted tubular part to each other, and

[0093] - Optionally, fix one or more functional components to the second knitted tubular part.

[0094] In a variant, at least one of the one or more functional components is a polymer film that is at least partially fusible.

[0095] The polymer film can be made of one or more materials selected from the above synthetic materials and polyurethane or combinations thereof.

[0096] In one embodiment, the polymer film comprises / is composed of polyurethane.

[0097] In a variant, after step (iii), the film forms a coating (or has dimensions determined such that a coating is formed) that covers at least 10%, preferably at least 25%, more preferably at least 40%, preferably at least 50%, more preferably at least 70%, particularly at least 80%, or 98% to the nearest + / -2% of the outer surface of the upper (or the first knitted tubular part), in particular except for the outer surface of the sole part (other than the first knitted tubular part) of the upper.

[0098] The coating can be continuous or discontinuous, and / or in the form of one or more (identical or different) patterns and / or one or more knitted fabrics, but generally covers the above-mentioned percentage of the outer surface.

[0099] Preferably, this setting is obtained by applying heat, one or more gas flows, particularly water vapor, and vacuum in combination to the footwear assembly during step (iii).

[0100] Advantageously, the method according to the invention enables one or more extended areas of the outer surface of the first knitted tubular part to be functionalized and thus ultimately one or more extended areas of the outer surface of the upper to be functionalized.

[0101] In a variant, at least one of the one or more functional components is selected from: at least partially fusible polymer films, heel reinforcement elements, logos, aesthetic elements, hard caps, reinforcement elements in the lace area, auxiliary knitted tubular parts, textile elements, shock-absorbing elements such as foams, auxiliary knitted tubular components, or combinations thereof.

[0102] In one embodiment, at least one of the one or more functional components is a shock-absorbing element, particularly a foam.

[0103] In one embodiment, at least one of the one or more functional components is selected from: at least partially fusible polymer films, heel reinforcement elements, logos, aesthetic elements, hard caps, reinforcement elements in the lace area, or combinations thereof.

[0104] The textile element can include one or more woven elements, knitted elements, non-woven elements, or combinations thereof.

[0105] The auxiliary knitted tubular part can be the same as or different from the first knitted tubular part. The description regarding the first tubular part or the second tubular part also applies to the auxiliary tubular part.

[0106] In a variant, the method includes providing a knitted tubular assembly, and the first knitted tubular part and the second knitted tubular part have an integral knitted structure with the knitted tubular assembly to form an element made of one knitted piece.

[0107] In this case, the first knitted tubular part and the second knitted tubular part are knitted simultaneously on a knitting machine and are thus made as a single knitted piece.

[0108] Alternatively, but not preferably, the first knitted tubular part is made of a knitted piece different from the knitted piece forming the second knitted tubular part.

[0109] In one variant, the method comprises arranging at least one functional component between the first knitted tubular part and the second knitted tubular part, in particular during step (ii) and / or step (iii).

[0110] In one variant, the first knitted tubular part forms the inner layer of the shoe upper and the second knitted tubular part forms the outer layer of the shoe upper.

[0111] In one variant, the first knitted tubular part comprises one or more at least partially fusible yarns, and the ratio of the weight of the one or more at least partially fusible yarns to the total weight of the first knitted tubular part is greater than or equal to 20%, preferably greater than or equal to 40%, more preferably greater than or equal to 60%, and in particular greater than or equal to 80%.

[0112] In one variant, the second knitted tubular part comprises one or more at least partially fusible yarns, and the ratio of the weight of the one or more at least partially fusible yarns to the total weight of the second knitted tubular part is less than or equal to 80%, preferably less than or equal to 60%, more preferably less than or equal to 40%, and in particular less than or equal to 20%.

[0113] In one variant, the first knitted tubular part comprises an opening area for inserting a foot, and the second knitted tubular part comprises an opening area for inserting a foot. The foot insertion opening areas overlap.

[0114] In one variant, the one or more at least partially fusible yarns form the at least one fusible part which preferably has a melting temperature less than or equal to T1, and T1 is preferably less than or equal to one or more heating temperatures.

[0115] In one variant, step (iii) comprises heating the preform to a heating temperature greater than or equal to Tp, where Tp ≥ T1.

[0116] In one variant, step (iii) comprises heating the moulded volume to a heating temperature greater than or equal to Tvm, where Tvm ≥ T1.

[0117] The temperature Tp and the temperature Tvm can be the same or different.

[0118] The method according to the invention makes it possible to apply different heating temperatures taking into account the nature of the materials of the footwear components.

[0119] In a variant, the upper obtained in step (iii) comprises a sole part, and the method comprises the step of fixing at least one sole element selected from a midsole and a wear-resistant sole to the sole part of the upper.

[0120] In a variant, the preform comprises an internal volume and perforations opening onto its outer surface, the internal volume and the perforations being in fluid connection.

[0121] Preferably, one or more gas flows, in particular water vapour, are sent onto the footwear assembly through the perforations of the preform.

[0122] Advantageously, the arrangement of the perforations of the preform enables heat to be distributed more regularly over the outer surface of the preform and thus enables an upper obtained by thermoforming with a more regular shape to be obtained, and also enables the fixing to be strengthened when one or more fusible parts are used for fixing one or more functional components to the first knitted tubular part and / or the second knitted tubular part and / or for fixing the first knitted tubular part and the second knitted tubular part to one another.

[0123] The preform comprises a sole part (intended to come into contact with the sole part of the envelope defined below), a lateral part (intended to come into contact with the lateral side of the envelope defined below), a medial part (intended to come into contact with the medial side of the envelope defined below), a front part in the extensions of the medial part, the lateral part and the sole part (intended to cover the front of the foot of the envelope defined below), and a rear part in the extensions of the medial part, the lateral part and the sole part (intended to cover the rear of the foot of the envelope defined below and thus to cover the heel and optionally the ankle).

[0124] In a preferred embodiment, the preform comprises perforations located in at least one of the aforementioned parts, in particular in each of the aforementioned parts.

[0125] Preferably, the preform comprises perforations distributed over the entire outer surface of the preform, in particular perforations intended to come into contact with the footwear assembly.

[0126] Preferably, the preform is hollow and comprises an internal volume, and the perforations are through openings which open onto the outer surface of the preform and lead to the internal volume, in particular opening onto the inner surface of the preform.

[0127] Preferably, the perforations comprise substantially circular perforations.

[0128] In a preferred embodiment, the perforations comprise (or consist of) perforations, the maximum dimension of which is included in a circle having a diameter greater than 1 mm, more preferably greater than or equal to 3 mm, preferably greater than or equal to 6 mm, particularly less than or equal to 20 mm, and particularly less than or equal to 10 mm.

[0129] In one embodiment, the ratio of the sum of the surface areas (cm2) of the perforations to the total surface area (cm2) of the outer surface of the preform is less than or equal to 60%, preferably less than or equal to 40%, more preferably less than or equal to 25%, and particularly greater than or equal to 10%.

[0130] This is because heat flows through the footwear assembly and also through the perforations of the preform into its internal volume and, conversely, from its internal volume through the perforations into the footwear assembly.

[0131] In one variant, the outer surface of the preform comprises at least one metal, particularly stainless steel, aluminium, iron or a combination thereof.

[0132] In one embodiment, the preform, particularly its outer surface, comprises / (consists essentially of) at least one metal or ferrous alloy or non-ferrous alloy, particularly selected from stainless steel, iron, aluminium or a combination thereof.

[0133] Specifically, the entire outer surface of the preform comprises at least one metal or at least one metal alloy.

[0134] In one variant, the outer surface of the preform comprises a glass-ceramic material, particularly the outer surface of the preform consists of a glass-ceramic material.

[0135] In one variant, the preform, particularly its outer surface, is subjected to a physical and / or chemical surface treatment.

[0136] This arrangement makes it possible to impart one or more additional thermal and / or mechanical properties to the preform, particularly improving the properties of corrosion resistance, wear resistance or impact resistance, thereby optimizing the use of the preform.

[0137] This arrangement advantageously makes it possible to significantly reduce the time of step (iii).

[0138] In the prior art, when thermoforming is carried out separately from the fixing step using a plastic preform, the thermoforming time is approximately 1 minute and 20 seconds. The inventors have observed that, without changing the footwear assembly, by using a metal preform, this time is divided by two. Description of the Drawings

[0139] The present invention will be better understood by reading the following description of embodiments of the invention given by way of non-limiting example with reference to the accompanying drawings, in which:

[0140] Figure 1 shows a first knitted tubular assembly including a first knitted tubular portion and a second knitted tubular portion;

[0141] Figure 2 shows a second example of a knitted tubular assembly including a first knitted tubular portion and a second knitted tubular portion;

[0142] Figure 3 shows a first example of a footwear assembly disposed on a foot-shaped preform;

[0143] Figure 4 shows Figure 3 a footwear assembly that is disposed on a preform located within a molded volume to perform transformation step (iii);

[0144] Figure 5 shows an example of a footwear item including an upper obtained at the end of transformation step (iii); and

[0145] Figure 6 shows a first example of an upper obtained after transformation step (iii). DETAILED DESCRIPTION

[0146] Figure 1Shows a first example of a knitted tubular assembly 10 made of a single piece 15, which includes a first knitted tubular portion 20 and a second knitted tubular portion 30, each portion being elbow-shaped and bent. Thus, the knitted tubular assembly 10 has a generally U-shape. The first knitted tubular portion 20 and the second knitted tubular portion 30 have an integral knitted structure with the knitted tubular assembly 10. The first knitted tubular portion 20 includes: an open distal end 22, which is preferably closed by stitching before being disposed on a preform; and an open proximal end 24, which defines an insertion area for the foot 26 and a volume 28 for receiving the foot. The second knitted tubular portion 30 includes: a distal end 32, which is closed during the knitting of the tubular assembly 10; and an open proximal end 34, which defines an insertion area for the foot 36 and a volume 38 for receiving the foot. Preferably, the first knitted tubular portion 20 and the second knitted tubular portion 30 include respective heel areas 25, 35, intended to receive the heel of the user. During programming of the knitting machine to knit the knitted tubular assembly 10, the partitioning of the first knitted tubular portion 20 and the second knitted tubular portion 30 is determined according to different knitting patterns (reverse plain knitting, straight plain knitting, ribbing, etc.) and different types of yarns (different due to their nature and / or color and / or their transparency and / or their fineness (dtex)). Thus, the concavity, thickness, appearance, and functionality of one or more of the determined areas can be changed, and this is done independently for the first knitted tubular portion 20 and the second knitted tubular portion 30.

[0147] Alternatively, a single one of the first knitted tubular portion 20 and the second knitted tubular portion 30 may include an elbow-shaped bent portion, such that the tubular assembly 10 has a generally L-shape.

[0148] The first knitted tubular portion 20 includes at least partially fusible yarns disposed in one or more portions. The second knitted tubular portion 30 may also include one or more fusible portions formed of at least partially fusible yarns. For example, the at least partially fusible yarns account for at least 30% and at most 60% of the total weight of the first knitted tubular portion by weight and are distributed throughout the first knitted tubular portion. For example, the at least partially fusible yarns account for at least 50% and at most 80% of the total weight of the second knitted tubular portion by weight and are distributed throughout the second knitted tubular portion. Of course, this arrangement can be changed according to the desired stability and flexibility.

[0149] Figure 2 A second example of the knitted tubular assembly 100 shown also is made of a single piece 150 and includes a first knitted tubular portion 200 and a second knitted tubular portion 300. The knitted tubular assembly 100 is substantially straight, and the first tubular portion 200 and the second tubular portion 300 do not include any elbow-shaped bent portions. Figure 3Shows a first example of a footwear assembly 40 placed on a foot-shaped preform 50.

[0150] The footwear assembly 40 includes Figure 1 the knitted tubular assembly 10 shown. A second tubular portion 30 is disposed within the foot-receiving volume 28 of the first tubular portion 20 such that the first tubular portion 20 and the second tubular portion 30 are overlapping.

[0151] The footwear assembly 40 further includes a functional assembly 60 as a heel reinforcement and a functional assembly 70 as a shock-absorbing shoe back. The functional assembly 60 and the functional assembly 70 are respectively disposed between the first knitted tubular portion 20 and the second knitted tubular portion 30 at the heel height between the shoe back portion and the rear foot portion. The functional assembly 60 extends perpendicular to the longitudinal axis L. Thus, the knitted tubular portions 20 and 30 respectively form an outer layer 80 and an inner layer 90 of the shoe upper 400, which are obtained after the transformation step (iii) and as Figure 6 shown. The footwear assembly 40 further includes a functional assembly 75, which is a polymer film, for example made of meltable polyurethane, sized such that it can cover at least 50% of the outer surface 21 of the first knitted tubular portion 20, particularly the entire outer surface 21, except for the sole portion 27. The step (ii) of shaping the footwear assembly 40 can be completed when the tubular assembly 10 has been placed on the preform 50 or before the tubular assembly is disposed on the preform 50. Then, Figure 4 the footwear assembly 40 placed on the preform 50 is disposed as in Figure 4In the molding volume defined between the outer mold 500 made of two parts 510, 520 and the preform 50 as shown. The part 510 and the part 520 define a volume in the shape of a foot that is complementary to the shape of the foot of the preform 50. Alternatively, the molding volume can also be defined between the outer surface of the preform 50 and a flexible airtight film, which includes a hollow shape that is substantially in the shape of a foot to match the footwear assembly provided on the preform 50. Then, the footwear assembly 40 can undergo the transformation step (iii) to obtain the upper 400, and this transformation step includes: thermoforming the footwear assembly 40 according to the foot shape of the preform 50, fixing the functional components 60, 70 to the first knitted tubular part 20 and the second knitted tubular part 30, fixing the functional component 75 to the first knitted tubular part 20, and at least partially fixing the first knitted tubular part 20 and the second knitted tubular part 30 to each other. Specifically, the inner surface 23 of the first knitted tubular part is arranged to directly abut against the outer surface 31 of the second knitted tubular part 30. The thermoforming and fixing are carried out in a single step and thus simultaneously. Therefore, heat, water vapor, and vacuum are applied to the footwear assembly 40 so as to press the footwear assembly 40, and thus including the functional components 60, 70, and 75, flat against the outer surface 51 of the preform 50. The molding volume is placed in a vacuum so that the footwear assembly 40 can be pressed flat against the outer surface 51, especially the functional component 75 thus perfectly matches the outer surface 21 of the first knitted tubular part 20.

[0152] Since the functional component 75 is fusible, it is fixed on the outer surface 21 of the first tubular part 20. The functional component 60 and the functional component 75 are adhered to the first tubular part 20 and the second tubular part 30 by means of the fusible parts they include, and / or by the fusible parts supported by the functional component 60 and the functional component 75 themselves, and / or using optional fusible adhesion means. Figure 6 The upper 400 as shown includes the functional components 60, 70, and 75, and these components are perfectly integrated, fixed, and shaped into the shape of the foot of the preform 50. There is no need to involve the step of laying the first knitted tubular part 20 flat. Therefore, the entire outer surface and inner surface of the first tubular part 20 and the second tubular part 30 can be functionalized without restricting the size of the functional components. In addition, since the fixing of the functional components and the thermoforming of the footwear assembly 10 are carried out simultaneously, the functional components are not thermally damaged.

[0153] Then, the sole part 450 of the upper 400 is fixed to the sole element 500 to obtain Figure 5The footwear item 1 shown. Thus, the upper 400 can include different knitting zones 401 to 406 of the first knitted tubular portion 20, which appear under the transparent coating 78 resulting from the transformation of the film 75. The zones 401 to 406 differ by their knitting pattern, their color, their elasticity or their stiffness. Thus, the zone 406 corresponds to a knitted unidirectional reinforcement element that strengthens the inner and outer portions of the upper 400.

Claims

1. A method for manufacturing a footwear item (1), comprising the steps of: (i) - providing a first knitted tubular part (20) comprising at least one fusible part and one or more functional components (60; 70; 75), wherein at least one of the functional components is a polymer film (75) that is at least partially fusible; (ii) - forming a footwear component (40) comprising the first knitted tubular part (20) and the one or more functional components (60; 70; 75), wherein during step (ii), the first knitted tubular part and the polymer film are assembled such that the polymer film is arranged and held in a three - dimensional manner on the first knitted tubular part by using one or more holding points, the first knitted tubular part being placed on a preform having a foot shape, and the one or more holding points being formed by at least one of the following: stitching, adhesion, and heat - fusion or a combination thereof; (iii) - transforming the footwear component (40) prepared in step (ii) and disposed on the preform (50) having a foot shape into an upper, the transformation step comprising: - thermo - forming the footwear component (40) to follow the foot shape of the preform (50), and - at least partially fixing the functional components (60; 70; 75) to the first knitted tubular part (20), and wherein the at least partially fusible polymer film (75) is disposed on the first knitted tubular part, and both the first knitted tubular part and the polymer film are arranged in a three - dimensional manner according to the outer surface of the preform having a foot shape, wherein the thermo - forming and the fixing are carried out in a single step, the single step comprising placing the footwear component (40) under vacuum and applying heat to the footwear component to melt or soften the fusible part of the first knitted tubular part and at least the fusible part of the polymer film, wherein the vacuum placement is done in a molding volume that receives the footwear component, wherein step (iii) comprises setting the footwear component, which was previously disposed on the foot - shaped preform in the molding volume, the molding volume being substantially a foot shape complementary to the shape of the preform, the molding volume being defined by a mold comprising a number of parts, and wherein the outer surface of the preform having a foot shape comprises at least one metal.

2. The method according to claim 1, characterized in that during the transformation step (iii), one or more gas flows are applied to the footwear component (40) in combination with heat in a single step.

3. The method according to claim 2, characterized in that the one or more gas flows are water vapor.

4. The method according to claim 1, characterized in that the method comprises providing a second knitted tubular part (30), and The footwear component (40) in step (ii) includes the first and second knitted tubular parts (20; 30) that are at least partially overlapped and connected to one or more functional components (60; 70; 75).

5. The method according to claim 4, wherein, the second knitted tubular part (30) includes at least one fusible part.

6. The method according to claim 4, wherein, the fixing in step (iii) allows at least partial fixing of the first knitted tubular part to the second knitted tubular part (20; 30) to each other.

7. The method according to claim 6, wherein, the fixing in step (iii) allows at least partial fixing of one or more functional components (60; 70; 75) to the second knitted tubular part (30).

8. The method according to claim 4, wherein, the method includes providing a knitted tubular assembly (10), and the first knitted tubular part (20) and the second knitted tubular part (30) have an integral knitted structure with the knitted tubular assembly (10) to form an element made of a knitted block (15).

9. The method according to claim 4, wherein, during step (ii) and / or during step (iii), the method includes disposing at least one functional component (60; 70) between the first knitted tubular part (20) and the second knitted tubular part (30).

10. The method according to claim 4, wherein, the first knitted tubular part (20) forms the outer layer (80) of the shoe upper (400), and the second knitted tubular part (30) forms the inner layer (90) of the shoe upper (400).

11. The method according to claim 4, wherein, the first knitted tubular part (20) includes an opening area for inserting the foot, the second knitted tubular part (30) includes an opening area for inserting the foot, and the opening area for inserting the foot of the first knitted tubular part and the opening area for inserting the foot of the second knitted tubular part are overlapped.

12. The method according to claim 4, wherein, the second knitted tubular part (30) includes one or more at least partially fusible yarns, and the ratio of the weight of the one or more at least partially fusible yarns to the total weight of the second knitted tubular part (30) is less than or equal to 80%.

13. The method according to claim 12, wherein, after step (iii), the polymer film (75) forms a coating (78) that covers at least 50% of the outer surface of the shoe upper (400).

14. The method according to claim 1, wherein, the first knitted tubular part (20) includes one or more at least partially fusible yarns, and the ratio of the weight of the one or more at least partially fusible yarns to the total weight of the first knitted tubular part (20) is greater than or equal to 20%.

15. The method according to claim 1, wherein, at least one of the one or more functional components is selected from: at least partially fusible polymer film, heel reinforcement element, logo, aesthetic element, hard cap, reinforcement element in the lace area, shock-absorbing element, auxiliary knitted tubular part, or a combination thereof.

16. The method according to claim 1, wherein, step (iii) includes heating the preform to a heating temperature greater than or equal to Tp, where Tp ≥ T1 and T1 is greater than or equal to the melting or softening temperature of the at least one fusible part.

17. The method according to claim 1, wherein, step (iii) includes heating the molded volume to a heating temperature greater than or equal to Tvm, where Tvm ≥ T1 and T1 is greater than or equal to the melting or softening temperature of the at least one fusible part.

18. The method according to claim 1, wherein, the upper (400) obtained in step (iii) includes a sole part (450), and the method includes the following step: fixing at least one sole element (500) selected from the midsole and the outsole to the sole part of the upper.

19. The method according to claim 1, wherein, the preform includes an internal volume and perforations opened on the outer surface of the preform, and the internal volume is in fluid connection with the perforations.

20. A footwear article obtained by the method according to claim 1.

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