Abstract
A shoe, a shoe production system and a method for producing a shoe including the steps: a. providing an upper assembly (2), wherein the upper assembly includes an upper (3) being mounted on a carrier (4), wherein the upper (3) includes a bottom section (5) being made from a thermoplastic polymer upper material; b. providing a sole molding unit (6), wherein the sole molding unit defines a cavity; c. inserting the upper assembly (2) at least partially into the cavity; introducing a midsole polymer composition comprising a molten thermoplastic polymer midsole material which has a melting temperature being equal or higher than the melting temperature of the thermoplastic polymer upper material into the cavity and foaming the molten thermoplastic polymer midsole material inside the cavity to provide a foamed midsole and to establish a material-bonded connection between the upper (3) and the foamed midsole (8).
Claims
1. A method for producing a shoe (1), the method comprising the steps: a. providing an upper assembly (2), wherein the upper assembly comprises an upper (3) being mounted on a carrier (4), wherein the upper (3) comprises a bottom section (5) being made from a thermoplastic polymer upper material; b. providing a sole molding unit (6), wherein the sole molding unit defines a cavity (7); c. inserting the upper assembly (2) at least partially into the cavity (7); and d. introducing a midsole polymer composition comprising a molten thermoplastic polymer midsole material which has a melting temperature equal or higher than the melting temperature of the thermoplastic polymer upper material into the cavity (7) and foaming the molten thermoplastic polymer midsole material inside the cavity (7) to provide a foamed midsole (8) and to establish a material-bonded, in particular fused, connection between the upper (3) and the foamed midsole (8).
2. The method according to claim 1, wherein step d. is performed by supercritical injection foaming.
3. The method according to claim 1, wherein the polymer composition in step d. comprises a physical blowing agent, in particular a physical blowing agent being in a supercritical state.
4. The method according to claim 1, wherein during step d. the bottom section (5) of the upper (3) is at least partially melted, in particular by the thermal energy of the molten thermoplastic polymer midsole material.
5. The method according to claim 1, wherein in step c. the upper assembly (2) is inserted such into the sole molding unit (6) that a closed, and in particular sealed, sole molding compartment (9) is formed being defined by the sole molding unit (6) and the upper assembly (2).
6. The method according to claim 1, wherein after step d. an outsole polymer composition comprising a molten polymer outsole material is introduced into the cavity (7) to provide an outsole (10) being material-bonded, in particular fused, to the foamed midsole (8).
7. The method according to claim 1, wherein the upper assembly (2) provided in step a. is held by a movable robotic arm (11) and wherein step c. is performed by the robotic arm (11).
8. The method according to claim 1, wherein the upper assembly (2) in step a. is provided by applying the molten thermoplastic polymer upper material onto the carrier (4) by means of a nozzle (12) in the form of at least one filament, in particular at least one continuous filament, to provide the upper (3) being mounted on the carrier (4).
9. The method according to claim 8, wherein the at least one filament is applied such on the carrier (4) that it forms a plurality of crossings with itself on the carrier (4) and/or a plurality of loops on the carrier (4), wherein a material-bonded connection is established at at least one crossing between different sections of the at least one filament.
10. The method according to claim 8, wherein the nozzle (12) comprises a material outlet (13) and a plurality of air openings (14, 15) being circumferentially arranged around the material outlet (13), wherein pressurized air is applied in such a manner onto the molten polymer upper material exiting the material outlet (13) that it is applied to the carrier (4) as a helical filament.
11. A shoe (1), in particular having been obtained by the method according to claim 1, the shoe (1) comprising an upper (3) comprising a thermoplastic polymer upper material and a foamed midsole (8) comprising a thermoplastic polymer midsole material, wherein the upper (3) and the foamed midsole (8) are directly material-bonded, in particular fused, with each other.
12. The shoe (1) according to claim 11, wherein the shoe (1) further comprises an intermediate material zone (16) in which the upper (3) and the foamed midsole (2) are directly material-bonded with each other, wherein the intermediate material zone (16) comprises the thermoplastic polymer upper material and the thermoplastic polymer midsole material.
13. The shoe (1) according to claim 12, wherein the intermediate material zone (16) is arranged between a midsole section (17) being devoid of the thermoplastic polymer upper material and an upper section (18) being devoid of the thermoplastic polymer midsole material.
14. The shoe (1) according to claim 12, wherein the intermediate material zone (16) comprises a gradient of the thermoplastic polymer upper material, which extends from the upper section (18) to the midsole section (17), and/or wherein the intermediate material zone (16) comprises a gradient of the thermoplastic polymer midsole material which extends from the midsole section (17) to the upper section (18).
15. The shoe (1) according to claim 11, wherein the melting temperature of the thermoplastic polymer midsole material is equal or higher than the melting temperature of the thermoplastic polymer upper material.
16. A shoe production system (100) configured for performing the method according to claim 1, the shoe production system (100) comprising a sole molding unit (6) which defines a cavity (7) and a movable robotic arm (11) being configured to hold the carrier (4) of the upper assembly (2).
17. The shoe production system (100) according to claim 16, further comprising a depositing unit (19) configured for depositing a thermoplastic polymer upper material on the carrier (4) held by the movable robotic arm (11).
18. The shoe production system (100) according to claim 17, wherein the depositing unit (19) comprises a nozzle (12).
19. The shoe production system (100) according to claim 18, wherein the nozzle (12) comprises a material outlet (13) and a plurality of air openings (14, 15) being circumferentially arranged around the material outlet (13) and configured to apply pressurized air in such a manner onto the molten thermoplastic polymer upper material exiting the material outlet (13) that it is applied to the carrier (4) as a helical filament.
20. The shoe production system (100) according to claim 18, wherein the depositing unit (19) further comprises a melting unit (20) with an extruder with screw (21) and barrel (22), in fluidic communication with the material outlet (13) of the nozzle (12).
Description
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
[0083] The herein described invention will be more fully understood from the detailed description given herein below and the accompanying drawings which should not be considered limiting to the invention described in the appended claims.
[0084] FIG. 1 shows a schematic cross sectional view of an upper assembly being inserted into a cavity of a sole molding unit as it is performed in an embodiment of the invention;
[0085] FIG. 2 shows a schematic view onto a heel edge of a shoe according to an embodiment of the invention and/or having been obtained by the method according to an embodiment of the invention;
[0086] FIG. 3 shows a schematic view of how an upper assembly can be provided according to an embodiment of the invention and/or a show production system according to an embodiment of the invention;
[0087] FIG. 4 shows a schematic top view of a nozzle as it can be used in some embodiments of the invention;
[0088] FIG. 5 shows a schematic perspective view of a nozzle as it can be used in some embodiments of the invention; and
[0089] FIG. 6 shows a detailed view of a depositing unit as it can be used in some embodiments of the invention.
DESCRIPTION OF THE EMBODIMENTS
[0090] FIG. 1 shows an upper assembly 2 which comprises a carrier 4 and an upper 3 being mounted on carrier 4. Carrier 4 can in this embodiment or any other embodiment described herein for example be a last, i.e. a shoe last. Upper 3 further comprises bottom section 5 which is made from a thermoplastic polymer upper material. In this embodiment, the boundary of bottom section 5 is indicated by the dashed line. However, it may in some embodiments well be the case that the bottom section and the rest of the upper are identical, e.g. they may be made from the same material and/or have the same structure, such as a non-woven, knit or woven structure. Upper assembly 2 is partially inserted into cavity 7 (see FIG. 3) defined by sole molding unit 6. Thereby, the upper assembly 2 and the sole molding unit 6 define together sole molding compartment 9. Sole molding compartment 9 is a part of the cavity defined by sole molding unit 6. The upper assembly, in particular upper 3, respectively its bottom section 5, and the sole molding unit 6 form together a fluid tight connection. Typically, when upper assembly 2 is inserted into cavity 7, cavity 7 and therefore also sole molding compartment 9 is filled with air, e.g. ambient air. It may also in this or any other embodiment as described herein be possible to apply a sub-atmospheric pressure to sole molding compartment 9 after partially inserting upper assembly 2 into cavity 7 of sole molding unit 6.
[0091] As a next step, a midsole polymer composition comprising a molten thermoplastic polymer midsole material is introduced into the cavity and thus also into sole molding compartment 9. This introduction may for example occur via injection inlet 24 which opens into cavity 7, respectively sole molding compartment 9. Since upper assembly 2 is partially introduced into cavity 7 and/or the sole molding compartment 9 is defined by upper assembly 2 and sole molding unit 6, the introduced molten thermoplastic polymer composition is provided onto bottom section 5 of upper 3 being introduced into cavity 7. As the molten thermoplastic polymer midsole material has an equal or higher melting temperature than the thermoplastic polymer upper material of bottom section 5 (and optionally of complete upper 3), the bottom section 5 partially or fully melts and a material-bonded connection being a fused connection between upper and the formed foamed midsole occurs without any additional adhesive. Furthermore, during introduction, foaming of the molten thermoplastic polymer midsole material is performed during step d. which provides the foamed midsole. This results in a produced shoe with a foamed midsole being directly material-bonded, i.e. fused, to an upper 3. Subsequently, cooling and/or curing can be performed and the produced shoe can be removed from sole molding unit 6 and carrier 4 can be removed from the produced shoe.
[0092] FIG. 2 shows a shoe 1 which can be obtained by the method according to the invention. Shoe 1 comprises upper 3 and foamed midsole 8. Upper 3 comprises a thermoplastic polymer upper material and foamed midsole 8 comprises a thermoplastic polymer midsole material. In addition, shoe 1 comprises outsole 10 being material-bonded to foamed midsole 8. Outsole 10 can for example be obtained in that after step d. of the method according to the invention, i.e. after foamed midsole 8 is produced and material-bonded to upper 3, a molten polymer outsole material, preferably a molten thermoplastic outsole material is introduced into cavity 7 defined by sole molding unit 6, respectively sole molding compartment 9 onto foamed midsole 8. Introduction of the molten polymer outsole material may for example occur via injection inlet 24 or via an additional separate injection inlet. Only thereafter the thus produced shoe is typically removed from sole molding unit 6 and carrier 4 is removed from upper 3.
[0093] FIG. 2 shows a view of shoe 1 on its heel edge, i.e. as indicated by the coordinate system along longitudinal direction L towards the sole tip of shoe 1. Vertical direction V extends perpendicularly thereto from foamed midsole 8 towards upper 3, respectively in the worn or operative state from the ground to the foot of the wearer. Transversal direction T is perpendicular to both longitudinal direction L and vertical direction V. Shoe 1 further comprises intermediate material zone 16 which is indicated by the two parallel extending dashed lines. When the molten thermoplastic polymer midsole material is introduced, e.g. injected, onto bottom section 5 of upper 3, bottom section 5 at least partially or fully melts and therefore forms upon cooling/and or curing a material-bonded, e.g. fused, connection between foamed midsole 8 and upper 3. Thereby intermediate material zone 16 can be formed, which comprises both the thermoplastic polymer upper material of the upper, respectively bottom section 5 and also the thermoplastic polymer midsole material. In contrast, midsole section 17, i.e. the rest of foamed midsole 8 is devoid of the thermoplastic polymer upper material. Vice versa, upper section 18 of upper 3, i.e. the rest of upper 18, is devoid of the thermoplastic polymer midsole material. Against vertical direction V there is a gradient of the thermoplastic polymer upper material in intermediate material zone 16 extending from upper section 18 to midsole section 17. This gradient is decreasing, i.e. the amount, such as the mass percentage, of the thermoplastic polymer upper material decreases from the intermediate material zone 16 extending from upper section 18 to midsole section 17. Furthermore, there is an opposite gradient in intermediate material zone 16 of the thermoplastic polymer midsole material extending along or in vertical direction V, i.e. from midsole section 17 to upper section 18. The gradient of the thermoplastic polymer midsole material decreases in intermediate material zone 16 from midsole section 17 to upper section 18. The gradient may also in this case be represented by a decreasing amount, e.g. mass percentage, of the thermoplastic polymer midsole material. In some embodiments, the intermediate material zone 16 may extend completely along the transverse direction T and the longitudinal direction L of shoe 1 and for example completely separate midsole section 17 from upper section 18. However, it may generally also be possible that intermediate material zone 16 may extend only along a certain portion of the transverse direction T and/or the longitudinal direction L of shoe 1. For example, the intermediate material zone may only be arranged at the periphery of shoe 1 and thus not in its center.
[0094] FIG. 3 shows a shoe production system 100 when being used to produce a shoe, e.g. for producing a shoe in the method according to the invention. Shoe production system 100 comprises sole molding unit 6, such as sole molding unit 6 as described with respect to FIG. 1, which defines cavity 7 being configured for molding a shoe sole, such as foamed midsole 8. Cavity 7 is defined by sidewalls circumferentially surrounding the cavity and bottom wall delimiting the bottom of the cavity (not visible). As can be seen, the cavity is open at the top portion, which allows to insert upper assembly 2 directly into cavity 7. Furthermore, shoe production system 100 comprises movable robotic arm 11 which holds carrier 4. For example, robotic arm 11 may form a form-locking and/or force-locking engagement with carrier 4. It may for example be possible that robotic arm 11 forms a snap fitting engagement with carrier 4. Robotic arm 11 is configured for moving carrier 4 in the 3-dimensional space. Particularly, it may generally be possible that robotic arm 11 is configured to move carrier 4 along three space axes, such as a vertical axis, a longitudinal axis and a transversal axis. Additionally, or alternatively, it may generally be possible that the movable robotic arm 11 is configured for rotating carrier 4 around a rotation axis. Shoe production system 100 further comprises control unit 23 which is configured to control the movement of robotic arm 11, particularly with respect to nozzle 12 being further comprised in the shown shoe production system 100. Nozzle 12 which may be part of depositing unit (see FIG. 6).
[0095] FIG. 3 depicts how upper assembly 2 can be provided in step a of the method according to the invention. In this embodiment, the molten thermoplastic polymer upper material is applied by nozzle 12 onto carrier 4. The robotic arm moves carrier 4 in the 3 dimensional space with respect to nozzle 4. As can be seen, molten thermoplastic polymer upper material is applied as a filament onto carrier 4 as a helical filament. After the application of the molten thermoplastic polymer upper material is finished, the upper assembly 2 comprising carrier 4 and upper 3 being mounted on carrier 4 is provided. As a next step in the method according to the invention, the upper assembly 2 is at least partially inserted into cavity 7 of sole molding unit 6, for example in the manner as shown in FIG. 1. The insertion may for example be done by movable robotic arm 11 being preferably controlled by control unit 23. After the upper assembly 2 has been inserted into cavity 7, step d. of the method according to the invention is performed, i.e. the midsole polymer composition is introduced into cavity 7 and foaming of the molten thermoplastic polymer midsole material is performed to establish a direct fused connection between upper 3, respectively its bottom section 5, and foamed midsole 8 to produce shoe 1. Thus, the complete shoe can be produced at a single location with a single system and fully automatically.
[0096] FIG. 4 shows a top view of nozzle 12 as it can be used in some embodiments of the invention. Nozzle 12 comprises centrally arranged material outlet 13. Furthermore, nozzle 12 comprises a plurality of air openings 14, 15 (only two openings are referenced for clarity purposes) being circumferentially arranged around material outlet 13. As can be seen, each air opening is arranged such that air being guided through it is guided inwardly, i.e. in the direction of the filament of molten thermoplastic upper material exiting material outlet 13. However, each air opening is also arranged such that pressurized air being guided through the air openings is applied in such a manner on the molten polymer upper material exiting the material outlet (i.e. the filament) that it is applied to the carrier as a helical filament. This is achieved by directing the pressurized air offset to the axis being perpendicular to material outlet 13 and extending through its center along the application direction in which the molten thermoplastic polymer material is applied to the carrier (i.e. in the direction the viewer views onto the nozzle in FIG. 4). This allows to effect a movement of the exiting molten thermoplastic polymer material such that it is applied onto the carrier as a helical filament. FIG. 5 shows a perspective view of nozzle 12 shown in FIG. 4, which further clarifies the configuration of air openings 14 and 15.
[0097] FIG. 6 shows a detailed view of a depositing unit 19 as it can be used in some embodiments of the invention. Depositing unit 19 comprises melting unit 20 which may be an extruder, such as a screw and barrel extruder having screw 21 and barrel 22. Melting unit 20 comprises material inlet 26 through which the thermoplastic polymer upper material can be inserted into melting unit 20 for example as solid granulate. This material is then melted inside melting unit 20 and transported towards nozzle 12 which may be a nozzle as shown in FIGS. 4 and 5. The molten thermoplastic polymer upper material is then applied via material outlet 13 out of nozzle 12. By means of pressurized air being applied through air inlet openings 14, 15 (see FIGS. 4 and 5), the molten thermoplastic polymer upper material is applied to carrier 4 as a helical filament. By moving carrier 4 in the 3-dimensional space, for example by a movable robotic arm (not shown here, see FIG. 3), an upper assembly 2 can be provided. The depositing unit can be controlled by depositing unit control unit 25. It may be possible that depositing unit control unit 25 is in some embodiments included into control unit 23 which controls the movement of movable robotic arm 11 (see FIG. 3).
