Manufacturing process of at least a part of a footwear item, for example a shoe, a sandal, a boot, etc., and in particular a footwear item for the practice of a sport.
Patent Information
- Application Number
- FR2022010476
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2022-10-12
- Publication Date
- 2025-03-21
- Estimated Expiration
- 2042-10-12
Smart Images
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Abstract
Description
Title of the invention: Method for manufacturing at least one part of an item of footwear, for example a shoe, a sandal, a boot, etc., and in particular an item of footwear for practicing a sport.
[0001] The present invention relates to the field of the manufacture of footwear, for example shoes, and in particular to the manufacture of footwear comprising a light and shock-absorbing sole, and in particular footwear for practicing a sport.
[0002] It is known to manufacture a sole in a first step and then to connect the sole to an upper, in particular at least partly made of textile, in a second step. The manufacture of footwear articles with a light and shock-absorbing sole requires numerous steps because the sole is made separately, most often from cross-linked ethylene vinyl acetate (EVA), then assembled by gluing to the upper.
[0003] The disadvantage of this known process is that it requires numerous manual gluing operations, which consume a lot of energy.
[0004] On the other hand, two direct injection processes on rod are already known:
[0005] - injection of thermoplastic, PVC or other elastomers. With this process, The material can be foamed using a chemical or physical foaming agent; however, the disadvantage of this process is that the resulting shoe sole material does not have the expected properties of a lightweight, cushioning sole. The lowest sole density that can be achieved with this process is greater than 0.5 g / cm3. In addition, the cushioning and comfort properties sought for the soles of running shoes, for example, are not achievable with this manufacturing process.
[0006] - direct injection of polyurethane onto the rod. In this case, foaming is obtained by chemical reaction of 2 compounds (Polyol and Isocyanate). The disadvantage of this process is that the density of the sole remains high (>0.35 g / cm3 in the best case).
[0007] Furthermore, the non-thermoplastic nature of polyurethane makes recyclability extremely difficult.
[0008] The invention therefore aims to propose a solution to all or part of these problems.
[0009] To this end, the present invention relates to a method of manufacturing at least one part of an item of footwear, for example a shoe, and in particular an item of footwear for practicing a sport, comprising the following steps: - providing a mold defining an open cavity, a shape of at least a portion of the cavity corresponding to a shape of a sole of the footwear article, the cavity being configured to receive, via at least one injection channel opening into the cavity, a mixture comprising a molten material and a supercritical fluid; - placing a rim of an opening of the open cavity in contact with a docking zone of a surface of at least one part of an upper of the footwear article, so that the surface of the at least one part of the upper ensures a closure of the cavity at the level of contact between the docking zone and the rim; - pressurize the cavity; - inject the mixture into the cavity; - depressurizing the mold cavity, to trigger an expansion of the mixture in the cavity and form the sole in a foamed material resulting from the expansion of the mixture, at least a portion of the surface of the at least a portion of the upper being taken in said foamed material of the sole.
[0010] According to these provisions, the method makes it possible to obtain, in a single injection step, a light and shock-absorbing sole of the footwear article connected to a part of an upper of the footwear article, with good resistance to detachment of the sole and the upper.
[0011] According to these provisions, a pressurization pressure in the cavity followed by a depressurization in the cavity allows an expansion of the mixture and the obtaining of the light and cushioning foamed material of the sole.
[0012] According to these provisions, the density of the sole is between 0.1 g / cm3 and 0.4 g / cm3, preferably between 0.15 g / cm3 and 0.25 g / cm3.
[0013] According to one embodiment, the invention comprises one or more of the following characteristics, alone or in a technically acceptable combination.
[0014] According to one embodiment, a pressurization pressure of the cavity is between 10 and 50 bars, preferably 15 bars.
[0015] According to one embodiment, the method further comprises, prior to the step of pressurizing the cavity, the following step: - placing a cover on the mold so as to form with the mold a closed volume comprising the cavity, and a complementary part of the cavity in said closed volume, the at least one part of the rod being located inside said closed volume, the complementary part and the cavity being located on either side of the closure of the cavity at the level of contact between the docking zone and the rim.
[0016] A pressurization pressure in the complementary part of the closed volume makes it possible to avoid leaks, at the contact between the docking zone and the rim, of a pressurization gas of the cavity.
[0017] According to one embodiment, the method comprises a step of assembling the part of the upper connected to the sole, with another part of the upper, the assembly forming the footwear article.
[0018] According to one embodiment, the assembly step comprises sewing the other part of the upper with the part of the upper connected to the sole.
[0019] According to one embodiment, the method further comprises the following steps, implemented before the step of placing the rim of the opening of the open cavity in contact with the docking zone of a surface of at least one part of a rod: - provide a support having a shape corresponding to the shape of a foot, - covering, at least in part, an external surface of the support with the at least one part of the upper of the footwear article, the at least one part of the surface of the at least one part of the upper covering a part of the external surface of the support corresponding to a sole of said foot, so that after placing the cover on the mold, the closed volume further comprises the support with the at least one part of the upper.
[0020] According to one embodiment, the at least one part of the rod is a complete rod.
[0021] According to one embodiment, the support is made of aluminum, steel, or plastic.
[0022] According to these provisions, the method makes it possible to obtain, in a single injection step and with a single mold, a complete footwear article comprising the sole of the footwear article connected to the complete upper of the shoe.
[0023] According to one embodiment, the mold is in a single part.
[0024] According to one embodiment, the mold comprises at least two parts and the provisioning step includes a step of assembling the at least two parts to form the mold.
[0025] According to one embodiment, the cavity is configured to receive the mixture via at least two injection channels opening into the cavity.
[0026] According to these provisions, the method makes it possible to obtain even more quickly, and with a more homogeneous filling of the mold cavity, a sole of the footwear article connected to a part of the upper of the footwear article.
[0027] According to one embodiment, the mold comprises at least one injection channel.
[0028] According to one embodiment, the support comprises at least one injection channel.
[0029] According to one embodiment, the method comprises a step of gluing at least one part of the surface of at least one part of the rod, the gluing step being carried out before the injection step.
[0030] According to one embodiment, the at least one portion of the surface of the at least one portion of the rod comprises thermofusible wires configured to melt at an injection temperature of the mixture.
[0031] According to these provisions, the resistance to detachment of the sole and the upper is reinforced.
[0032] According to one embodiment, the method further comprises the following steps: - provide inserts configured to be positioned in the mold cavity; - position the inserts in the mold cavity.
[0033] According to one embodiment, the inserts are positioned to be inserted at an external surface of the sole, or to be embedded inside the sole.
[0034] According to these provisions, the abrasion resistance of the sole is reinforced, or the dynamism of the sole is improved, depending on whether the inserts are respectively inserted towards an external portion of the sole, for example with one or more inserts made of rubber or thermoplastic material, or embedded inside the sole, for example with one or more inserts made of carbon plate or thermoplastic material.
[0035] According to one embodiment, at least one part of the surface of the at least one part of the rod is at least partly perforated or open.
[0036] According to these provisions, the resistance to detachment of the sole and the upper is reinforced.
[0037] According to one embodiment, at least one part of the surface of at least one part of the rod is textured or perforated in contact with the docking zone.
[0038] According to these provisions, the resistance to detachment of the sole and the upper is further reinforced.
[0039] According to these provisions, a peel strength greater than 2.5 N / mm is obtained, measured according to the ISO NF EN 1392 standard.
[0040] According to one embodiment, the molten material is an elastomeric thermoplastic polymer.
[0041] According to an exemplary implementation, the thermoplastic polymer is a thermoplastic polyurethane (TPU), or an ether-amide block copolymer (PEBA), or an ethylene vinyl acetate (EVA), or a polyolefin, or an ether-ester block copolymer, or a styrene-based elastomer, or a mixture of these different components.
[0042] According to one embodiment, the supercritical fluid is nitrogen in a supercritical state or carbon dioxide in a supercritical state or a mixture of nitrogen and carbon dioxide in a supercritical state.
[0043] According to one aspect, the invention also relates to an item of footwear, for example a shoe, and in particular an item of footwear for practicing a sport, obtained by the method according to one of the embodiments described above.
[0044] According to another aspect, the invention relates to a device for manufacturing at least one part of a footwear article, the device comprising a mold defining an open cavity, a shape of at least one part of the cavity corresponding to a shape of a sole of the footwear article, the cavity being configured to receive, via at least one injection channel opening into the cavity, a mixture comprising a molten material and a supercritical fluid, a rim of an opening of the open cavity being configured to be placed in contact with a docking zone of a surface of at least one part of an upper of the footwear article, so that the surface of the at least one part of the upper ensures a closure of the cavity at the contact between the docking zone and the rim, so that said device is thus configured to implement the method according to one of the embodiments described above.
[0045] According to one embodiment, the device further comprises a cover configured to be placed on the mold so as to form with the mold a closed volume comprising the cavity, and a complementary part of the cavity in said closed volume, the at least one part of the upper of the footwear article being located inside said closed volume, the complementary part and the cavity being located on either side of the closure of the cavity at the contact between the docking zone and the rim, the device thus being configured to implement the method according to one of the implementation modes described above.
[0046] According to one embodiment, the device further comprises a support having a shape corresponding to a shape of a foot, an external surface of the support being configured to be covered with the at least one portion of the upper of the footwear article, the at least one portion of the surface of the at least one portion of the upper covering a portion of the external surface of the support corresponding to a sole of said foot.
[0047] For a better understanding, an embodiment and / or implementation of the invention is described with reference to the attached drawings representing, by way of non-limiting example, an embodiment or implementation respectively of a device and / or a method according to the invention. The same references in the drawings designate similar elements or elements whose functions are similar.
[0048] [Fig.l] is a perspective view of a mold, in a single part, of the cover corresponding to the mold, and of a shoe upper mounted on a support, before the step of placing the upper on the rim of the mold cavity, according to an embodiment of the invention
[0049] [Fig.2] is a perspective view of a mold, in three parts, of the cover corresponding to the mold, and of a shoe upper mounted on a support, before the step of placing the upper on the edge of the mold cavity, according to an embodiment of the invention
[0050] [Fig.3] is a perspective view of a mold, in one part, of the cover corresponding to the mold, and of a part of an upper of a shoe, before the step of placing the upper part on the rim of the cavity of the mold, according to an embodiment of the invention
[0051] [Fig.4] is a perspective view of the part of the upper connected to a sole obtained after implementing the method according to an embodiment of the invention, and of the shoe obtained after implementing an additional step of assembling the part of the upper with another part of the upper.
[0052] [Fig.5] is a sectional view of a rod with its support, placed on the mold, before the injection step, according to an embodiment of the invention; in this figure the mold cover is shown before its placement on the mold
[0053] [Fig.6] is a sectional view of a rod with its support, placed on the mold, under a cover forming with the mold a closed pressurized space on either side of the edge of the mold cavity, before the injection step, according to the method of implementing the invention of [Fig.5]
[0054] [Fig.7] is a perspective view of a rod with its support, placed on the mold, before the injection step, according to the method of implementing the invention of Figures 5 and 6; in this figure the mold cover is shown before its placement on the mold
[0055] [Fig.8] is a perspective view of the shoe obtained, with the support of the upper, after implementation of the method according to the embodiment of the invention of figures 5, 6, and 7.
[0056] [Fig.9] is a perspective view of a rod support with a seal placed on an area of the support corresponding to a docking area of the surface of the part of the rod, according to the embodiment of the invention corresponding to figures 5, 6, 7 and 8
[0057] [Fig. 10] is a perspective view of an upper with an open surface at the part of the upper intended to be taken in the foamed material of the sole obtained according to an embodiment of the invention
[0058] [Fig. 11] is a perspective view of another upper with a solid surface at the level of the part of the upper intended to be taken in the foamed material of the sole obtained according to an embodiment of the invention
[0059] [Fig. 12] is a perspective view of another upper with a perforated surface at the part of the upper intended to be taken in the foamed material of the sole obtained according to an embodiment of the invention
[0060] [Fig. 13] is a perspective view of another upper with an openwork or textured surface near the docking zone at the level of the part of the upper intended to be taken in the foamed material of the sole obtained according to an embodiment of the invention
[0061] [Fig. 14] is a sectional view of a rod with its support, placed on a mold comprising several injection channels, before the injection step, according to an embodiment of the invention
[0062] [Fig. 15] is a sectional view of a rod with its support, placed on the mold, before the injection step, according to an embodiment of the invention in which an injection channel passes through the support of the rod.
[0063] [Fig. 16] is a perspective view of inserts configured to be placed in the mold cavity so as to be associated with the sole obtained after overmolding with the foamed material, according to one embodiment of the invention.
[0064] [Fig. 17] is a sectional view of an upper with its support placed on the mold before the injection step, with the inserts placed in the mold cavity so as to be incorporated into the foamed material forming the sole, according to one embodiment of the invention.
[0065] [Fig. 18] is a sectional view of an upper with its support placed on the mold, after the injection step, with the inserts placed in the mold cavity and incorporated into the foamed material forming the sole, according to one embodiment of the invention.
[0066] [Fig. 19] is a sequencing diagram of the steps of the method, according to one embodiment of the invention.
[0067] With reference to [Fig. 19], the invention relates to a method 100 for manufacturing at least a part of an article of footwear, for example a shoe 10, shown in FIGS. 4 or 8, using a step 107 of injecting, into a cavity 2 of a mold 1, a supercritical mixture comprising a molten thermoplastic material and a gas in a supercritical state, so as to foam the thermoplastic material in order to obtain satisfactory properties of a foamed material which forms a light and shock-absorbing sole 3 of the shoe 10; in particular, FIGS. 4 or 8 show the part of the shoe 10 obtained at the end of the method 100, with the part 9 of the upper taken in the foamed material of the sole 3. To obtain this result, the cavity 2 has at least in part a shape corresponding to the final shape of the foam sole 3 that it is desired to obtain; this is illustrated in particular in figures 3 and 5.
[0068] In order to foam the molten thermoplastic material to obtain said foamed material which forms the sole 3, the method consists of pressurizing the cavity 2 of the mold 1, in particular by injecting a gas into said cavity 2, before injecting the supercritical mixture into the cavity 2, then depressurizing the cavity 2 in order to trigger expansion and foaming of the thermoplastic mixture in the cavity 2 in order to obtain the foamed material of the sole 3.
[0069] In order for a part 9 of the upper of the shoe 10 to be taken in said foamed material of the sole 3, said part 9 of the upper is suitably placed in the cavity 2 of the mold; for this purpose, as illustrated in Figures 3 and 5, the cavity 2 comprises an opening with a rim 5 on which is placed a zone 6, called the docking zone 6, of a surface 7 of the part of the upper 9, so that the surface 7 of the part of the upper 9 ensures a closure of the cavity at the contact between the docking zone 6 and the rim 5.
[0070] In order to be able to put the cavity 2 of the mold 1 under pressure, in particular by injecting a gas into said cavity 2, it is then essential to ensure sufficient sealing, in particular against gas, of the closure of the cavity 2 at the level of the contact between the docking zone 6 and the rim 5; the thickness of the rod being variable, the rod being able to take complex shapes, with significant dimensional tolerances, it can be difficult to obtain the desired sealing. A particularly advantageous solution can be the use of counter pressure in the zone of the rod 9 which is not immersed in the cavity 2, i.e. in the zone of the rod which is on the other side of the closure relative to the cavity 2. In [Fig.5] in particular, said zone of the rod 9 which is immersed in the cavity 2 is located in the lower part of the figure, and the part of the rod 9 which is not immersed in the cavity is located above the straight line joining the two points of the docking zone 6, designated by the references 5, 6 in figures 5 and 6.
[0071] To create the counter pressure, before the injection step 107 of the supercritical mixture into the cavity 2 of the mold 1, the method 100 comprises for example a step 103bis of placing a cover 13 on the mold 1 so as to form with the mold 1 a closed volume comprising the cavity 2, and a complementary part 14 of the cavity 2 in said closed volume, the complementary part 14 and the cavity 2 being located on either side of the closure of the cavity 2 at the level of the contact between the docking zone 6 and the rim 5. [Fig. 6] in particular shows the cover 13 placed on the mold 1, in order to form the closed volume comprising the cavity 2 on the one hand and the complementary volume 14 on the other hand; the surface 7 of the part of the upper 9 intended to be taken in the foamed material of the sole 3 is located inside the cavity 2 of the mold 1, and the surface of the other part of the rod is located inside the complementary part 14 of the cavity 2 in the closed volume formed by the cover 13 placed on the mold 1. In [Fig.5] in particular the cover 13 of the mold 1 is shown above the mold which corresponds to it, but the person skilled in the art will understand that the method works just as well with a mold 1 above the cover 13 as illustrated by way of example in [Fig.l] in perspective. As illustrated in Figures 5 and 6, gaskets 15 may also be placed at a contact zone between the cover 13 and the mold 1 to ensure appropriate sealing of the closed volume constituted by the cover 13 and the mold 1.
[0072] The complementary part 14 is pressurized, for example by injecting a gas into said complementary part 14 at a pressure similar to the pressure of the cavity 2 so that the sealing defects at the level of the zone 6 and the rim 5 do not create a leak of a pressurizing gas between the cavity 2 and the complementary part 14, the pressure in the complementary part 14 acting as a counter pressure opposing the pressure in the cavity 2. The injection 107 of the supercritical mixture into the cavity 2 can then take place, for example via an injection channel 4 passing through the mold 1, as illustrated in [Fig.6].
[0073] For example, a cavity pressurization pressure is between 5 bars and 50 bars, preferably equal to 15 bars.
[0074] With reference to [Fig. 19], we describe the complete sequence of the steps of the method 100 for manufacturing a shoe 10, according to an embodiment which therefore comprises the following steps:
[0075] - provide 103 a mold 1 defining an open cavity 2, a shape of at least a portion of the cavity 2 corresponding to a shape of a sole 3 of the shoe 10, the cavity 2 being configured to receive, via at least one injection channel 4 opening into the cavity 2, a mixture comprising a molten material and a supercritical fluid; - placing 105 a rim 5 of an opening of the cavity 2 open in contact with a docking zone 6 of a surface 7 of at least one part of an upper 9 of the shoe 10, so that the surface 7 of the at least one part of the upper 9 ensures a closure of the cavity at the level of the contact between the docking zone 6 and the rim 5;
[0076] - pressurize 105bis the cavity 2, in particular by injecting a gas into said cavity 2 ; - inject 107 the mixture into cavity 2;
[0077] -depressurize 108 the cavity 2 of the mold, in particular by evacuating the gas from said cavity 2, to trigger an expansion of the mixture in the cavity 2 and form the sole 3 in a foamed material resulting from the expansion of the mixture, the at least a part of the surface 7 of the at least one part 9 of the upper being taken in said foamed material of the sole 3.
[0078] According to these provisions, the method makes it possible to obtain, in a single injection step 107, a light and shock-absorbing sole of the shoe 10 connected to a part of an upper 9 of the shoe 10, with good resistance to detachment of the sole 3 and the upper 9.
[0079] Pressurization in the cavity 2 followed by depressurization in the cavity 2 allows expansion of the mixture and the production of the light and cushioning foamed material of the sole. Pressurization pressure in the complementary part 14 of the closed volume makes it possible to ensure sealing, in particular against gas, of the closure of the cavity 2, at the level of the contact between the docking zone 6 and the rim 5.
[0080] The molten material is for example an elastomeric thermoplastic polymer.
[0081] According to an exemplary implementation, the thermoplastic polymer is a thermoplastic polyurethane (TPU), or an ether-amide block copolymer (PEBA), or an ethylene vinyl acetate (EVA), or a polyolefin, or an ether-ester block copolymer, or a styrene-based elastomer, or a mixture of these different components.
[0082] The supercritical fluid is for example nitrogen in a supercritical state or carbon dioxide in a supercritical state or a mixture of nitrogen and carbon dioxide in a supercritical state.
[0083] The density of the sole 3 finally obtained is between 0.1 g / cm3 and 0.4 g / cm3, preferably between 0.15 g / cm3 and 0.25 g / cm3.
[0084] Furthermore, the part of the upper 9 taken in the foamed material of the sole 3 makes it possible to obtain a detachment resistance greater than 2.5 N / mm, measured according to the ISO NF EN 1392 standard.
[0085] In particular, step 105bis of pressurizing the cavity 2 may for example comprise the following step:
[0086] - place 103bis a cover 13 on the mold 1 so as to form with the mold 1 a closed volume comprising the cavity 2, and a complementary part 14 of the cavity 2 in said closed volume, at least one part of the rod 9 being located inside said closed volume, the complementary part 14 and the cavity 2 being located on either side of the closure of the cavity 2 at the level of the contact between the docking zone 6 and the rim 5.
[0087] A pressurization pressure in the complementary part 14 of the closed volume makes it possible to avoid leaks, at the level of contact between the docking zone 6 and the rim 5, of a pressurization gas of the cavity 2.
[0088] According to an exemplary implementation, illustrated in [Fig.3], the part 9 of the rod is placed directly on the rim 5 of the opening of the cavity 2 of the mold 1, without using a support 8 to hold the rod.
[0089] In particular, the method may comprise a complementary step of assembling the part of the upper 9 connected to the sole 3 obtained after the depressurization step, with another part 9' of the upper, the assembly forming the shoe 10, as illustrated in [Fig.4]. By way of example, the assembly step may comprise sewing the other part 9' of the upper with the part of the upper 9 connected to the sole 3.
[0090] According to another example of implementation, illustrated in Figures 5 and 6, the part 9 of the upper is first placed on a support 8 so as to cover (102) at least in part an external surface of said support 8, said support 8 having a shape corresponding to a shape of a foot; a part of the surface 7 of the part of the upper 9, intended to be taken in the foamed material of the sole 3, covers a part of the external surface of the support 8 corresponding to a sole of said foot.During the step 105 of placing the part of the rod 9 on the rim 5 of the cavity 2, the part of the rod 9 is thus placed, with the support 8, on the rim 5 of the cavity 2, so that after the placement 103bis of the cover 13 on the mold 1, the closed volume further comprises the support 8 with the part of the rod 9; the surface 7 of the part of the rod 9 intended to be taken in the foamed material of the sole 3 is located inside the cavity 2 of the mold 1, with a corresponding part of the support 8, and the surface of the other part of the rod 9, with another corresponding part of the support 8, is located inside the complementary part 14 of the cavity 2 in the closed volume formed by the cover 13 placed on the mold 1.
[0091] The rod 9 may for example be a complete rod, as illustrated for example in [Fig.7].
[0092] The support 8 can be made, for example, of aluminum, steel, or plastic.
[0093] Thus, the method 100 makes it possible to obtain, in a single injection step 107, a complete shoe 10 comprising a sole 3 of the shoe connected to a complete upper 9 of the shoe 10, as illustrated in [Fig.8].
[0094] The mold 1 is in a single part, or the mold 1 comprises several parts 1', 1”, 1'”, as illustrated in [Fig. 2], and the step of providing 103 the mold 1 comprises a step of assembling the different parts 1', 1”, 1” to form the mold 1. For example, the multi-part mold 1', 1”, 1'” may comprise a mold base 1'”, and two halves 1', 1” of a ring-shaped part of the mold, as illustrated in [Fig. 2]; said two halves 1', 1” are configured to form a ring when assembled, said ring being configured to form the rim 5 of the cavity 2 when it is placed on the bottom 1 ” ' of the mold 1, said rim 5 then being configured to receive the docking zone 6 of the rod portion 9. Furthermore, as illustrated in Figures 5 and 6, one or more gaskets 15' may also be placed at a contact area between the different parts 1', 1”, 1'” of the mold to ensure proper sealing of the mold 1.
[0095] To enable the implementation of the injection step 107, the cavity 2 of the mold is configured to receive, via at least one injection channel 4, 4', 4”, 4”' opening into the cavity 2, the mixture comprising a molten material and a supercritical fluid.
[0096] For example, the mold may comprise an injection channel 4 opening into the cavity 2, as illustrated in [Fig. 6]. According to another example, the injection channel 4 opening into the cavity 2 may pass through the support 8 of the rod 9, as illustrated in [Fig. 15].
[0097] According to yet another example, the cavity 2 is configured to receive the mixture via at least two injection channels 4', 4”, 4”' opening into the cavity 2, as illustrated in [Fig. 14] on which are represented, by way of example, 3 injection channels 4', 4”, 4'”. Thus, the method 100 makes it possible to obtain more quickly, and with a more homogeneous filling of the cavity of the mold, a sole 3 of the shoe 10 connected to a part of the upper 9 of the shoe 10.
[0098] To improve the strength of the connection between the upper 9 and the sole 3, it is in particular possible to provide an additional step of gluing 106 of the part of the surface 7 of the part of the upper 9, the gluing step 106 being carried out before the injection step 107. Alternatively, or in combination with the gluing step 106, the part of the surface 7 of the part of the upper 9 may comprise hot-melt threads configured to melt at an injection temperature of the mixture. Thus, the resistance to detachment of the sole and the upper is reinforced.
[0099] According to an example of implementation of the method, the part of the surface 7 of the part of the upper 9, intended to be taken in the foamed material of the sole 3, is solid as illustrated in [Fig. 1 1]. To reinforce the resistance to detachment, it is also possible to provide that the part of the surface 7 of the part of the upper 9, intended to be taken in the foamed material of the sole 3, is perforated, i.e. the part of the surface 7 comprises holes as illustrated in [Fig. 12] or in [Fig. 3] with for example 3 holes passing through the part of the surface 7 of the part of the upper 9; it is also possible to provide that the part of the surface 7 is at least partly open as illustrated in [Fig. 10] with for example said part of the surface 7 almost completely open except on a part of this surface 7 near the docking zone 6. In the case shown in [Fig.3], on which 3 holes pass through the part of the surface 7 of the part of the rod 9, and on which the part of the rod 9 intended to be taken in the foamed material of the sole 3 is not placed on a support 8, the cover 13 must ensure the closing of the holes or. openings of the part of the surface 7 of the part of the rod 9 during the steps 105bis of pressurizing the cavity 2 and of injecting 107 the mixture into the cavity. For this purpose, the cover 13 may for example, as illustrated in [Fig.3], rest, for example with a substantially flat and plane inner surface, on said part of the surface 7 of the part of the rod 9 so as to close the holes or openings present on this part of the surface 7 of the part of the rod 9.
[0100] Yet another way of reinforcing the resistance to detachment consists in providing that the part of the surface 7 of the part of the upper 9, intended to be taken in the foamed material of the sole 3, is textured or perforated in contact with or near the docking zone 6, as illustrated in [Fig. 13].
[0101] In order to improve the abrasion resistance of the sole 3, or the rigidity of the sole 3, the method 100 may comprise the complementary steps of providing 104 and positioning 104bis one or more inserts 12, 12', 12” configured to be positioned in the cavity 2 of the mold 1;
[0102] For example, the insert(s) 12, 12' shown in [Fig. 16] are positioned to be inserted at an external surface of the sole, as illustrated respectively before and after the step 107 of injecting the mixture into the cavity 2 in FIGS. 17 and 18; according to another example, one or more inserts 12” may be positioned to be embedded inside the sole 3, as illustrated respectively before and after the step 107 of injecting the mixture into the cavity 2 in FIGS. 17 and 18.
[0103] According to these provisions, the abrasion resistance of the sole is reinforced, or a rigidity of the sole is improved, depending on whether respectively the inserts 12, 12' are inserted towards an external portion of the sole 3, for example with inserts 12, 12' made of rubber or thermoplastic material, or whether the insert is or the inserts 12” are embedded inside the sole 3, for example with inserts 12” made of carbon plate or thermoplastic material.
[0104] According to one aspect, the invention also relates to an article of footwear, for example a shoe 10 obtained by the method 100 according to one of the embodiments previously described.
[0105] According to another aspect, the invention also relates to a device comprising a mold 1, and optionally a cover 13, and optionally a support 8, configured to implement the method 100 according to one of the embodiments previously described.
[0106] According to one embodiment, the device comprises a mold 1 defining an open cavity 2, a shape of at least a part of the cavity 2 corresponding to a shape of a sole 3 of the shoe 10, the cavity 2 being configured to receive, via at least one injection channel 4, 4', 4”, 4'” opening into the cavity 2, a mixture comprising a molten material and a supercritical fluid, a rim 5 of an opening of the open cavity 2 being configured to be placed in contact with a docking zone 6 of a surface 7 of at least one part of an upper 9 of the shoe 10, so that the surface 7 of the at least one part of the upper 9 ensures a closure of the cavity at the level of the contact between the docking zone 6 and the rim 5, so that said device is thus configured to implement the manufacturing method 100 according to one of the implementation examples described above.
[0107] According to a complementary exemplary embodiment, the device further comprises a cover 13 configured to be placed on the mold 1 so as to form with the mold a closed volume comprising the cavity 2, and a complementary part 14 of the cavity in said closed volume, the at least one part of the upper 9 of the shoe being located inside said closed volume, the complementary part 14 and the cavity 2 being located on either side of the closure of the cavity 2 at the level of the contact between the docking zone 6 and the rim 5, the device thus being configured to implement the manufacturing method 100, according to one of the embodiments described above.
[0108] According to another complementary exemplary embodiment, the device further comprises a support 8 having a shape corresponding to a shape of a foot, an external surface of the support 8 being configured to be covered with at least one part of the upper 9 of the shoe, the at least one part of the surface 7 of the at least one part of the upper 9 covering a part of the external surface of the support corresponding to a sole of said foot.
Claims
Claims
1. Method (100) for manufacturing at least a part of an article of footwear (10) comprising the following steps: - providing (103) a mold (1) defining an open cavity (2), a shape of at least a part of the cavity (2) corresponding to a shape of a sole (3) of the article of footwear (10), the cavity (2) being configured to receive, via at least one injection channel (4, 4', 4”, 4'”) opening into the cavity (2), a mixture; - placing (105) a rim (5) of an opening of the cavity (2) open in contact with a docking zone (6) of a surface (7) of at least one part of an upper (9) of the footwear article (10), so that the surface (7) of the at least one part of the upper (9) ensures a closure of the cavity at the level of the contact between the docking zone (6) and the rim (5); - pressurizing (105bis) the cavity (2); - injecting (107) the mixture into the cavity (2);- depressurizing (108) the cavity (2) of the mold, to trigger an expansion of the mixture in the cavity (2) and form the sole (3) in a foamed material resulting from the expansion of the mixture, the at least one part of the surface (7) of the at least one part (9) of the upper being taken in said foamed material of the sole (3) the method (100) being characterized in that the mixture comprises a molten material and a supercritical fluid.;
2. Method (100) according to claim 1, further comprising, prior to the step of pressurizing (105bis) the cavity (2), the following step: - placing (103bis) a cover (13) on the mold (1) so as to form with the mold (1) a closed volume comprising the cavity (2), and a complementary part (14) of the cavity (2) in said closed volume, the at least one part of the rod (9) being located inside said closed volume, the complementary part (14) and the cavity (2) being located on either side of the closure of the cavity (2) at the level of the contact between the docking zone (6) and the rim (5).
3. Method (100) according to claim 2, further comprising the following steps, carried out before the step of placing (105) the rim (5) of the opening of the cavity (2) open in contact with the docking zone (6) of a surface (7) of the at least one part of an upper (9): - providing (101) a support (8) having a shape corresponding to a shape of a foot, - covering (102), at least in part, an external surface of the support (8) with the at least one part of the upper (9) of the footwear article (10), the at least one part of the surface (7) of the at least one part of the upper (9) covering a part of the external surface of the support (8) corresponding to a sole of said foot, so that after the placement (103bis) of the cover (13) on the mold (1), the closed volume further comprises the support (8) with the at least one part of the upper (9).
4. Method (100) according to one of claims 1 to 3, in which the cavity (2) is configured to receive the mixture via at least two injection channels (4', 4”, 4'”) opening into the cavity (2).
5. Method (100) according to one of claims 1 to 4, in which the mold (1) comprises at least one injection channel (4).
6. Method (100) according to one of claims 3 to 5, in which the support (8) comprises at least one injection channel (4).
7. Method (100) according to one of claims 1 to 6, comprising a step of gluing (106) at least one part of the surface (7) of at least one part of the rod (9), the gluing step (106) being carried out before the injection step (107).
8. Method (100) according to one of claims 1 to 7, in which the at least part of the surface (7) of the at least part of the rod (9) comprises thermofusible wires configured to melt at an injection temperature of the mixture.
9. Method (100) according to one of claims 1 to 8, further comprising the following steps: - providing (104) inserts (12, 12') configured to be positioned in the cavity of the mold; - positioning (104bis) the inserts (12, 12') in the cavity (2) of the mold.
10. Method (100) according to one of claims 1 to 9, wherein the at least part of the surface (7) of the at least part of the rod (9) is at least partly perforated or open.
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15. Method (100) according to one of claims 1 to 10, in which at least one part of the surface (7) of the at least one part of the rod (9) is textured or perforated in contact with the docking zone (6). Method (100) according to one of claims 1 to 11, in which the molten material is an elastomeric thermoplastic polymer. The method (100) of any one of claims 1 to 12, wherein the supercritical fluid is nitrogen in a supercritical state or carbon dioxide in a supercritical state or a mixture of nitrogen and carbon dioxide in a supercritical state. Footwear article obtained by the method (100) according to one of claims 1 to 13. Device for manufacturing at least one part of a footwear article (10), the device comprising a mold (1), defining an open cavity (2), a shape of at least one part of the cavity (2) corresponding to a shape of a sole (3) of the footwear article (10), the cavity (2) comprising a mixture, injected into the cavity via at least one injection channel (4, 4', 4”, 4”') opening into the cavity (2), a rim (5) of an opening of the open cavity (2) being configured to be placed in contact with a docking zone (6) of a surface (7) of at least one part of an upper (9) of the footwear article (10), so that the surface (7) of the at least one part of the upper (9) ensures a closure of the cavity at the contact between the docking zone (6) and the rim (5), the device being characterized in that the mixture includes a molten material and a supercritical fluid,such that said device is thus configured to implement the method (100) according to one of claims 1 to 13.,