System and method for manufacturing article of footwear including sole structure

Abstract

A method of forming a cushioning element. The method includes placing a first sheet adjacent an outer surface of a first mold portion, the first mold portion including a first mold cavity. The method includes pressing a portion of a first sheet into a first mold portion and into a first mold cavity with a molding tool, wherein at least a portion of the molding tool extends into the first mold cavity. The method includes applying a negative pressure to the first mold cavity to draw the portion of the first sheet into the first mold cavity, and joining a second sheet to the first sheet to form the cushioning element.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the priority of U.S. Patent Application No. 18 / 490,395, filed on October 19, 2023, and International Application No. PCT / US2023 / 077321, filed on October 19, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure generally relates to systems and methods for manufacturing footwear articles including a sole structure, and more particularly to systems and methods for manufacturing a sole structure incorporating a fluid - filled bladder (such as a cushioning element). Background Art

[0004] This section provides background information related to the present disclosure, which is not necessarily prior art.

[0005] Footwear articles typically include an upper and a sole structure. The upper can be formed of any suitable material to receive, secure, and support a foot on the sole structure. The upper can cooperate with laces, straps, or other fasteners to adjust the fit of the upper around the foot. A bottom portion of the upper adjacent to the bottom surface of the foot is attached to the sole structure.

[0006] The sole structure typically includes a layered arrangement extending between a ground surface and the upper. One layer of the sole structure includes an outsole that provides wear resistance and frictional attachment to the ground surface. The outsole can be formed of rubber or other materials that impart durability and wear resistance as well as enhanced frictional attachment to the ground surface. Another layer of the sole structure includes a midsole disposed between the outsole and the upper. The midsole provides cushioning for the foot and can be partially formed of a polymeric foam material that elastically compresses under an applied load to cushion the foot by attenuating ground reaction forces. The midsole can additionally be coupled to or alternatively incorporate a fluid - filled bladder, such as a cushioning element, to increase the durability of the sole structure and to provide cushioning to the foot by elastically compressing under an applied load to attenuate ground reaction forces. Generally, the design of the bladder focuses on balancing the support and cushioning characteristics for the foot, which are related to the responsiveness of the bladder when elastically compressed under an applied load. Brief Description of the Drawings

[0007] The drawings described herein are for illustrative purposes only of selected configurations and are not intended to limit the scope of the present disclosure.

[0008] Figure 1 is a perspective view of a system according to the present disclosure.

[0009] Figures 2A to 2F shows images of various molding tools according to the present disclosure.

[0010] Figure 3A Shows an image of a forming tool according to the present disclosure.

[0011] Figure 3B Is Figure 3A A perspective view of a region of the forming tool.

[0012] Figure 4A Is for Figure 1 A perspective view of an upper die part and a lower die part in a system.

[0013] Figure 4B Is for Figure 1 A perspective view of the lower die part in a system.

[0014] Figures 5A to 5K Shows Figure 1 The configurations and aspects of the system at various stages of a thermoforming process.

[0015] Figures 6A to 6B Shows an image of a buffer element manufactured using the method according to the present disclosure.

[0016] Figure 7A Includes two line graphs, each graph illustrating a comparison of a series of wall thickness measurements at different positions of buffer elements formed without a forming tool with a series of wall thickness measurements at different positions of four buffer elements formed according to the system and / or method of the present disclosure.

[0017] Figure 7B Includes two line graphs, each graph illustrating a comparison of a series of wall thickness measurements at different positions of buffer elements formed with a forming tool with a series of wall thickness measurements at different positions of buffer elements formed according to the system and / or method of the present disclosure.

[0018] Figure 8 Includes a line graph illustrating a comparison of a series of wall thickness measurements at different positions of two buffer elements formed without a forming tool with a series of wall thickness measurements at different positions of buffer elements formed according to the system and / or method of the present disclosure.

[0019] Figure 9 Is a cross-sectional view of buffer elements formed with and without the forming tool according to the present disclosure, each marked with corresponding wall thickness measurements at various positions of each buffer element.

[0020] Figure 10 Is a cross-sectional view of other buffer elements formed with and without the forming tool according to the present disclosure, each marked with corresponding wall thickness measurements at various positions of each buffer element.

[0021] Figure 11 Cross-sectional views of other buffer elements formed with and without the forming tool according to the present disclosure, each with corresponding wall thickness measurements marked at various positions of each buffer element.

[0022] In all the figures, corresponding reference numerals represent corresponding parts. Detailed Description

[0023] Example configurations will now be described more fully with reference to the accompanying drawings. The example configurations are provided so that this disclosure will be thorough and will fully convey the scope of the disclosure to those of ordinary skill in the art. Specific details, such as examples of specific components, devices, and methods, are set forth to provide a thorough understanding of the configurations of the present disclosure. It will be apparent to those of ordinary skill in the art that specific details need not be employed, and the example configurations may be embodied in many different forms and that the specific details and example configurations should not be construed as limiting the scope of the present disclosure.

[0024] The terminology used herein is for the purpose of describing particular example configurations only and is not intended to be limiting. As used herein, the singular articles "a", "an", and "the" may also be intended to include the plural forms, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "includes", and "having" are inclusive and thus specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein should not be construed as necessarily requiring them to be performed in the particular order discussed or illustrated, unless specifically identified as an order of performance. Additional or alternative steps may be employed.

[0025] When an element or layer is referred to as "on another element or layer", "engaged to", "connected to", "attached to", or "coupled to" another element or layer, it may be directly on the other element or layer, engaged, connected, attached, or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as "directly on another element or layer", "directly engaged to", "directly connected to", "directly attached to", or "directly coupled to" another element or layer, intervening elements or layers may not be present. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" versus "directly between", "adjacent" versus "directly adjacent", etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0026] The terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers, and / or sections. These elements, components, regions, layers, and / or sections should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or section from another region, layer, or section. Unless the context clearly indicates otherwise, terms such as "first", "second", and other numerical terms do not imply an order or sequence. Thus, without departing from the teachings of the exemplary configurations, the first element, component, region, layer, or section discussed below may be referred to as the second element, component, region, layer, or section.

[0027] In the following discussion, unless otherwise specified, when used to describe a numerical value, the terms "about", "approximately", "substantially", etc. mean a variation of + / −10% of that value.

[0028] The present disclosure relates to a system for thermoforming one or more cushioning elements, such as Figure 1 the system 100 shown in, which improves the wall thickness uniformity of the cushioning element and reduces the amount of material used during the thermoforming process.

[0029] Figure 1 An exemplary thermoforming system 100 in accordance with aspects disclosed herein is illustrated. The system 100 may include an upper die portion 102 having a plurality of die cavities, a lower die portion 103 having a plurality of die cavities, a first sheet, a second sheet, and a forming tool 108 having a plurality of protrusions. As will be discussed further in detail below, by using the forming tool 108 and / or by uniquely configuring its protrusions within the die cavities of the upper die portion 102 or the lower die portion 103, the system 100 may be capable of forming one or more cushioning elements having improved wall thickness uniformity and / or including less material than conventional cushioning elements.

[0030] The system 100 may further include a sheet feeder or conveyor system 110 for introducing the first sheet and the second sheet between the upper die portion 102 and the lower die portion 103 during thermoforming and for conveying the formed sheet (i.e., the cushioning element) out of the die portions 102, 103 after processing.

[0031] In some cases, system 100 can be a robot-controlled thermoforming system and can also include at least one robotic arm, such as robotic arm 112. Robotic arm 112 can be capable of positioning the forming tool 108 (including its protrusions) to a set position in the upper die section 102 or the lower die section 103 during the thermoforming process. Robotic arm 112 can also include an end effector, which can be configured to hold the forming tool 108. In the case of using an end effector, the end effector can be custom-designed and / or specially selected to ensure that the forming tool 108 is accurately positioned in the die cavity of the upper die section 102 or the lower die section 103 as required.

[0032] System 100 can also include one or more vacuum systems, one or more heating systems, and / or one or more cooling systems to facilitate the thermoforming process. The vacuum system can be used to expose the first sheet and the second sheet to a negative pressure (e.g., below atmospheric pressure). This pressure differential also enables system 100 to form the sheet into the shape required for the cushioning element. As Figure 1 shown, the vacuum system 114 can be coupled to the upper die section 102 to pull the sheet into one or more die cavities of the upper die section 102, or the vacuum system 116 can be coupled to the lower die section 103 to pull the sheet into one or more die cavities of the lower die section 103. Vacuum systems suitable for system 100 are known in the art.

[0033] The heating systems 118, 120 can be used to expose the sheet to thermal energy (e.g., from about 125°C to about 225°C, such as from about 145°C to about 205°C, or from about 165°C to about 185°C) to make the sheet flexible (i.e., by raising the temperature of the sheet) to form into a cushioning element. If system 100 includes one or more heating systems, the heating systems 118, 120 can be positioned within system 100 as needed, for example, above the upper die section 102 or, for example, below the lower die section 103, as Figure 1 shown. The heating systems 118, 120 can also be used to expose the forming tool 108 to thermal energy, and in some cases, this exposure can improve the thermoforming of the cushioning element and / or the ability of the forming tool 108 to process the first sheet and / or the second sheet. Heating systems suitable for use are known in the art.

[0034] The cooling systems 122, 124 can be used to lower and / or maintain the temperature of certain components of system 100. If system 100 includes one or more cooling systems, the cooling systems 122, 124 can be positioned within system 100 as needed, for example, above the upper die section 102 or, for example, below the lower die section 103, as Figure 1As shown. The cooling systems 122, 124 can also be used to reduce the temperature of the forming tool 108, and in some cases, such exposure can improve the thermoforming of the cushioning element and / or the ability of the forming tool 108 to process the first sheet and / or the second sheet. Suitable cooling systems are known in the art.

[0035] In addition to the foregoing, the system 100 can also include one or more additional components and / or systems, such as but not limited to monitoring devices, external heating or cooling systems, hydraulic systems, safety mechanisms, or any other components and / or systems that will be incorporated into a single-sheet or double-sheet thermoforming system to ensure efficient and reliable operation.

[0036] In some aspects, the system of the present disclosure includes a forming tool, such as Figure 1 the forming tool 108 shown in. In some aspects, the system herein includes only one forming tool or can include multiple forming tools. Any suitable forming tool for the thermoforming process can be used. However, in some cases, the forming tool can include a base layer and a plurality of protrusions extending from the base layer. In these cases, each protrusion can correspond to at least one cushioning element. That is, the number, arrangement, and / or shape of the protrusions can be the same as the number, arrangement, and / or shape of the die cavities of the upper die part or the lower die part of the system. As will be discussed in further detail below, the number, arrangement, and / or shape of different groups of corresponding die cavities between the die parts directly correspond to the number, arrangement, and / or shape of the cushioning elements formed during the thermoforming process.

[0037] The number of protrusions on the forming tool can range from 1 protrusion to 40 protrusions, such as 8 protrusions to 32 protrusions, or 16 protrusions to 24 protrusions. The number of protrusions on the forming tool can be at least 4, at least 6, at least 8, at least 10, at least 12, at least 14, at least 16, at least 18, at least 20, at least 22, at least 24, at least 26, at least 28, at least 30, at least 32, at least 34, at least 36, at least 38, or at least 40 protrusions.

[0038] Regardless of the number of protrusions, in some cases, each of the plurality of protrusions can be arranged on the forming tool in any manner (e.g., spaced apart, grouped together in a region, etc.), and in some cases, it can be arranged according to the arrangement of the die cavities of the die parts 102, 103. For example, Figure 2AIllustrated is an exemplary forming tool, forming tool 200, which includes a base layer 202 and protrusions 220a to 280d that are spaced apart on the tool 200 but not arranged by region. In other instances, the forming tool may include multiple regions, each region including two or more protrusions, and in some cases, these regions may further enable a thermoforming system to simultaneously form multiple cushioning elements. Figure 2B Also illustrated is an exemplary forming tool, forming tool 200, which includes a base layer 202 and protrusions 220a to 280d arranged by regions 220, 240, 260, and 280 on the tool 200.

[0039] Regardless of the number or arrangement of the protrusions, in some cases, each of the multiple protrusions may have an irregular three-dimensional shape, such as a tube shape or a shape corresponding to the sole structure of a shoe. The tube shape may be, but is not limited to, a rectangular tube shape, a U-shaped tube, an L-shaped tube, and / or an H-shaped tube. Figures 2C to 2F Illustrated is an exemplary forming tool including protrusions having various arrangements, numbers, and / or shapes.

[0040] Regardless of the number, arrangement, and / or shape of the protrusions, in some cases, the multiple protrusions may be uniformly designed to include one or more features (e.g., length, width, height, curvature, grooves, depressions, etc.) such that each protrusion is identical to each other. In other cases, the multiple protrusions may be individually designed to include one or more features such that at least one protrusion is different from another protrusion.

[0041] In some cases, the length of the protrusion may be in the range from 4 cm to 10 cm, such as 5 cm to 9 cm or 6 cm to 8 cm. In some cases, the width of the protrusion may be in the range from 4 cm to 10 cm, such as 5 cm to 9 cm or 6 cm to 8 cm. In some cases, the height of the protrusion may be in the range from 1.5 cm to 8 cm, such as 3 cm to 6.5 cm or 4.5 cm to 5 cm.

[0042] Figure 3A Illustrated is a forming tool 300, which includes a base layer 302 and multiple protrusions 320a to 380d, each protrusion having a substantially rectangular tube shape, each protrusion being individually designed to include one or more features, and each protrusion being arranged by regions 320, 340, 360, and 380 on the forming tool 300. Figure 3B Provided is Figure 3A a detailed and close-up view of region 320 of the forming tool 300.

[0043] In region 320, protrusions 320a, 320b, 320c, and 320d are arranged on the base layer 302 such that a space can be provided between protrusions 320a and 320b, a space can be provided between protrusions 320b and 320c, and a space can be provided between protrusions 320c and 320d. The width of each of these spaces can be uniform, or in some cases, the width of each of these spaces can vary. Whether the spaces are uniform or variable, the width of the spaces can be in the range from 0.5 cm to 4 cm, such as 1.5 cm to 3 cm.

[0044] Protrusions 320a, 320b, 320c, and 320d can have heights, widths, and lengths that are consistent or different relative to each other, and in some cases, these heights, widths, and lengths can be optimized or designed according to the mold cavity and / or a plurality of buffer elements. For example, in order to produce a plurality of buffer elements with varying lengths, the lengths of protrusions 320a and 320d can be longer than the lengths of protrusions 320b and 320c, or vice versa.

[0045] Now turning to protrusion 320a, protrusion 320a includes four side surfaces 322a, 324a, 326a, 328a and an outermost surface 330a that faces away from the molding tool and the base layer 302 and includes four edges 332a, 334a, 336a, 338a. As shown, each side surface 322a, 324a, 326a, 328a is substantially aligned with and corresponds to exactly one edge 332a, 334a, 336a, 338a of the outermost surface 330a.

[0046] In some cases, protrusion 320a can be centered along the longitudinal axis A1 - A1 of region 320 such that the outermost surface 330a of protrusion 320a can extend symmetrically along the latitudinal axis A2 - A2. In these cases, the outermost surface 330a can also include two end portions and a central portion, for example, located between the two end portions at the intersection of axes A1 - A1 and A2 - A2.

[0047] Along the outermost surface 330a, protrusion 320a can extend from the base layer 302 to have a uniform height, or can extend from the base layer 302 to have a varying height. In the case where protrusion 320a has a varying height along the outermost surface 330a, protrusion 320a can undulate or bend along the latitudinal axis A2 - A2 such that the central portion of the outermost surface 330a can be recessed or protruded relative to the base layer 302. That is, due to the central region being recessed or protruded, the two end portions of the outermost surface 330a that are close to the edges 332a and 336a of the outermost surface and correspond to the side surfaces 322a and 326a diverge towards the central portion.

[0048] It should be understood that the above discussion regarding region 310 and / or protrusion 320a applies to any region, protrusion, surface, and / or edge of the forming tool as described herein, and each region, protrusion, surface, and / or edge of the forming tool can be optimized independently. That is, each of these individual components of the forming tool can be optimized individually without relying on the optimization of another component.

[0049] The material of the forming tool can be selected based on the barrier film used and / or the desired thermoforming process sequence. That is, the forming tool 108 can be formed from commercially available plug assist materials optimized for single- and / or double-sheet plug assist thermoforming. For example, commercially available plug assist materials can include one or more materials such as polymeric materials or materials comprising one or more metals. In some cases, the commercially available plug assist materials can have a density in the range from about 50 lb / ft 3 (800.923 kg / m 3 ) to about 60 lb / ft 3 (961.108 kg / m 3) a density within the range of and / or having a thermal conductivity of about 0.10 BTU / hr-ft-°F (0.17 W / m°K). In some cases, commercially available plunger assist materials can have a coefficient of thermal expansion of about 20 x 10-6 in / in / °F (36 x 10-6 m / m / °C) and / or have a compressive strength within the range from about 13,000 psi (about 89 MPa) to about 14,000 psi (about 97 MPa), such as from about 13,250 psi (about 91 MPa) to about 13,750 psi (about 95 MPa), or from about 13,400 psi (about 92 MPa) to about 13,600 psi (about 94 MPa). In some cases, commercially available plunger assist materials can have an operating temperature within the range from about 300°F (about 148°C) to about 400°F (about 205°C), such as from about 325°F (about 162°C) to about 375°F (about 190°C), or from about 340°F (about 171°C) to about 360°F (about 182°C). As used herein, the term "operating temperature" refers to the highest temperature at which a commercially available plunger assist material can be used for an extended period of time without significant change in performance. Commercially available plunger assist materials can be most compatible with or can exhibit enhanced properties with barrier films including multiple layers and / or barrier films including crystalline polyethylene terephthalate (CPET), polyethylene terephthalate (PET), ethylene vinyl alcohol (EVOH), low density polyethylene (LDPE), thermoplastic polyurethane (TPU), and / or combinations thereof. In some examples, commercially available plunger assist materials can include, consist essentially of, or consist of FLXT composite foam manufactured by CMT Materials, LLC (Attleboro, Massachusetts).

[0050] In some aspects, the systems of the present disclosure include die sections, such as Figure 1 the upper die section 102 and the lower die section 103 shown in Figure 4A illustrated that can be in Figure 1The die parts 402, 403 used in the thermoforming system. The upper die part 402 may include an upper part 402a and a lower part 402b. The lower part 402b has a flat or substantially flat bottom surface 402c. And the lower die part 403 may include a lower part 403a and an upper part 403b. The upper part 403b has a flat or substantially flat top surface 403c facing the bottom surface 402c of the upper die part. The bottom surface 402c and the top surface 403c may each include a plurality of die cavities provided therein. In some cases, the upper part 402a of the upper die part 402 and / or the lower part 403a of the lower die part 403 may be connected to a negative pressure source, such as vacuum systems 414, 416, to pull a sheet (not shown) into one or more die cavities of the upper die part 402 and the lower die part 403 respectively.

[0051] In some cases, when the upper die part and the lower die part are in a closed configuration during the thermoforming process, the bottom surface 402c of the upper die part 402 may be aligned with the top surface 403c of the lower die part 403. This alignment enables a die cavity of the upper die part 402 to correspond to a die cavity of the lower die part 403. That is, the alignment of the upper die part 402 and the lower die part 403 forms different sets of corresponding die cavities between the die parts 402, 403. In these cases, a different set of corresponding die cavities corresponds to a buffer element. That is, the number, arrangement, shape, and / or characteristics of the different sets of corresponding die cavities directly correspond to the number, arrangement, shape, and / or characteristics of the buffer element. For example, Figure 4B is provided Figure 4A A top view of the top surface 403c of the lower die part 403 of. As shown, the top surface 403c includes sixteen die cavities 403d to 403s, which are aligned with eight die cavities of the bottom surface (not shown) to generate sixteen different sets of corresponding die cavities between the upper die part 402 and the lower die part 403. These sixteen different sets of corresponding die cavities may form Figure 8 the buffer element shown in

[0052] The bottom surface 402c and the top surface 403c may include from 1 to 40 mold cavities, such as from 8 to 36 mold cavities, or from 12 to 24 mold cavities. The bottom surface 402c and the top surface 403c may include at least 1, at least 2, at least 4, at least 6, at least 8, at least 10, at least 12, at least 14, at least 16, at least 18, at least 20, at least 22, at least 24, at least 26, at least 28, at least 30, at least 32, at least 34, at least 36, at least 38, or at least 40 mold cavities.

[0053] Regardless of the number of mold cavities, in some cases, each of the plurality of mold cavities may be arranged in any manner (e.g., spaced apart, grouped together) on the upper mold part 402 or the lower mold part 403, and in some cases, may be arranged to correspond to protrusions on the molding tool. For example, 16 mold cavities may be arranged on the bottom surface 402c or the top surface 403c in a 4 by 4 mold cavity configuration, or for example, 24 mold cavities may be arranged on the bottom surface 402c or the top surface 403c in a 4 by 6 mold cavity configuration (or vice versa, in a 6 by 4 mold cavity configuration).

[0054] Regardless of the number or arrangement of the mold cavities, in some cases, each of the plurality of mold cavities may have an irregular shape, such as a partial tube shape or a shape corresponding to the sole structure of a shoe. The partial tube shape may be, but is not limited to, a partial cylindrical tube shape, a partial rectangular tube shape, a partial U - shaped tube, a partial L - shaped tube, and / or a partial H - shaped tube. In other cases, the innermost surface of the mold cavity may have a wavy curvature, and in some instances, the mold cavity corresponds to a molding tool or a protrusion on a molding tool, as discussed above with respect to Figures 3A to 3B discussed.

[0055] In some aspects, the system of the present disclosure includes two sheets, such as Figures 5A to 5KThe first sheet 504 and the second sheet 506 shown in . The sheets can have various thicknesses (measured by sheet gauge), and these thicknesses can be selected according to the desired thickness of the cushioning element. In some instances, the first sheet can have a greater thickness than the thickness of the second sheet, or in another instance, the second sheet can have a greater thickness than the thickness of the first sheet. It is also contemplated that the first sheet can have a thickness equal to the thickness of the second sheet. In some instances, the first sheet and / or the second sheet can have a sheet gauge of about 20 thou (0.508 mm) to about 90 thou (2.286 mm), such as about 35 thou (0.889 mm) to about 75 thou (1.905 mm), or about 50 thou (1.270 mm) to about 60 thou (1.524 mm). In other instances, the first sheet and / or the second sheet can have a sheet gauge less than about 90 thou (2.286 mm), less than about 85 thou (2.159 mm), less than about 80 thou (2.032 mm), less than about 75 thou (1.905 mm), less than about 70 thou (1.778 mm), less than about 65 thou (1.651 mm), less than about 60 thou (1.524 mm), less than about 55 thou (1.397 mm), less than about 50 thou (1.270 mm), less than about 45 thou (1.143 mm), less than about 40 thou (1.016 mm), less than about 35 thou (0.889 mm), less than about 30 thou (0.762 mm), less than about 25 thou (0.635 mm), or less than about 20 thou (0.508 mm). As used herein, the term "thou" refers to one thousandth of an inch, i.e., 0.001 inches (0.0254 mm).

[0056] The system of the present disclosure can be configured to form a cushioning element using the above components. For example, during a thermoforming process, the system can be configured to introduce a first sheet between an upper die portion and a lower die portion, introduce a forming tool between the upper die portion and the lower die portion at a set position of the die cavity relative to the lower die portion, press the forming tool into the first sheet, and introduce a second sheet between the upper die portion and the lower die portion. In some cases, after introducing the second sheet, the system can also be configured to position a second forming tool between the upper die portion and the lower die portion at a set position of the die cavity relative to the upper die portion, and press the second forming tool into the second sheet. It should be understood that in other instances, the system can be configured to introduce the first sheet and the second sheet simultaneously or sequentially between the upper die portion and the lower die portion, or can be configured to perform the steps associated with forming the second sheet before the steps associated with forming the first sheet.

[0057] Figures 5A to 5K These exemplary configurations of the system (system 500) at various stages of the thermoforming process are illustrated in accordance with an embodiment of the present disclosure.

[0058] Figure 5A System 500 is illustrated prior to the introduction of a first sheet 504 and a second sheet 506 between an upper die portion (not shown) and a lower die portion (not shown). As shown, system 500 may include a sheet feeder or conveyor system 510 that can be used to introduce sheets 504, 506 between the die portions. In some instances, system 500 may also include heating systems 518, 520 that subject the first sheet 504 and the second sheet 506 to thermal energy prior to their introduction between the die portions, as Figure 5B shown. This thermal energy raises the temperature of sheets 504, 506 to a temperature that is optimal for forming and melting.

[0059] Figure 5C System 500 is illustrated configured to first introduce a first sheet 504 between an upper die portion 502 and a lower die portion 503. In other instances, although not shown, system 500 may be configured to introduce the first sheet 504 and the second sheet 506 between the upper die portion 502 and the lower die portion 503 simultaneously or sequentially. As discussed with respect to Figure 4A the upper die portion 502 may include an upper portion 502a and a lower portion 502b, the lower portion 502b having a flat or substantially flat bottom surface 502c, and the lower die portion 503 may include a lower portion 503a and an upper portion 503b, the upper portion 503b having a flat or substantially flat top surface 503c that faces the bottom surface of the upper die portion 502. The bottom surface 502c and the top surface 503c may each include a plurality of die cavities disposed therein, such as die cavities 503d to 503s on the top surface 503c.

[0060] When system 500 is in an open configuration, the first sheet 504 may be introduced between the upper die portion 502 and the lower die portion 503 and positioned adjacent to the top surface 503c such that the plane of the sheet 504 is generally aligned with the top surface 503c. As used herein, the term "open configuration" refers to the upper die portion and the lower die portion being configured to form a gap between the die portions. In this configuration, the gap is large enough to allow the components of the system (e.g., the first sheet, the second sheet, the forming tool, etc.) to enter the system.

[0061] As Figure 5DAs shown, once the first sheet 504 is positioned adjacent to the top surface 503c, the first sheet 504 can then contact the top surface 503c. That is, the system 500 can be configured to move the lower die part 503 towards the first sheet 204 such that the first sheet 204 can contact the top surface 503c. In some cases, the first sheet 504 can be simultaneously exposed to a negative pressure environment (e.g., below atmospheric pressure) by the vacuum system 514 so that the sheet 504 is drawn into one or more die cavities (not shown) of the lower die part 503.

[0062] In other cases, the forming tool 508 can be introduced into the system 500 between the upper die part 502 and the lower die part 503 such that when pressed into the first sheet 504, the forming tool 508 is in a set position relative to the die cavities (not shown) of the lower die part 503. Once in the set position, the forming tool 508 can be held in the set position for a period of time ranging from about 0.10 s to about 2 s, such as from about 0.25 s to about 1.75 s, or from about 0.50 s to about 1.25 s. In the case where the forming tool 508 includes a plurality of protrusions, once the forming tool 508 is introduced into the system 500, each protrusion can be in a set position relative to one die cavity of the lower die part 503. When the forming tool 508 is positioned between the upper die part 502 and the lower die part 503, in some cases, the first sheet 504 can be simultaneously exposed to a negative pressure environment (e.g., below atmospheric pressure) by the vacuum system 514 so that the sheet 504 is drawn into one or more die cavities (not shown) of the lower die part 503.

[0063] Figure 5E A detailed and close-up view of a single protrusion 508a of the forming tool 508 in a set position relative to a single die cavity 503d of the lower die part 503 is provided.

[0064] As Figure 5E shown, the set position of the protrusion 508a can be in the z-position relative to the die cavity. As used herein, the term "z-position" describes the spatial orientation of the protrusion relative to the die (e.g., die surface and / or die cavity) after the forming tool is introduced into the system. Referring to a three-dimensional Cartesian coordinate system including an origin (reference point), x-axis, y-axis, and z-axis, the term "z-position" refers to the position of the lowest point of the protrusion relative to the die cavity (or a reference point on the die, such as the die surface) along the z-axis. Relative to the reference point, the z-position can be in the range of about -18 mm to about -10 mm, such as about -16 mm to about -14 mm, or about -15 mm to about -12.5 mm, where the reference point is at the surface of the die and is equal to 0.

[0065] Once the forming tool is positioned at the set position, the forming tool can be pressed (or extended) into the first sheet at an offset distance relative to the surface of the mold cavity. That is, the outermost surface of the forming tool can be positioned at an offset distance away from the inner surface of the first cavity. In the case where the forming tool includes a plurality of protrusions, after the forming tool is pressed into the first sheet, each protrusion can be located at an offset distance D1 - D1 relative to the surface of the mold cavity 503d, as Figure 5F shown. As used herein, the term "offset distance" refers to the minimum distance between the protrusion and the surface of the mold cavity. This distance is measured after the forming tool is pressed into the first sheet (or the second sheet). The offset distance can be in the range of about 0.1 mm to about 20 mm, such as about 1 mm to about 15 mm, or about 5 mm to about 10 mm.

[0066] Without being bound by any particular theory, the set position and / or the offset distance can ensure that the forming tool 508 imparts the desired characteristics to the cushioning element (e.g., wall thickness uniformity, less material, etc.).

[0067] When the system 500 is in the open configuration, the forming tool 508 can be removed from the lower mold part 503. In some cases, the forming tool 508 can be removed from the lower mold part 503 after a time period of about 0.10 s to about 2 s (such as about 0.25 s to about 1.75 s, or about 0.50 s to about 1.25 s).

[0068] In some cases, after the forming tool 508 is removed from the lower mold part 503, the first sheet can be exposed to a negative pressure environment (e.g., below atmospheric pressure) by the vacuum system 516 so that the sheet 504 is drawn into the mold cavities 503d to 503k of the lower mold part 503, as Figure 5G shown. It should be understood that the above discussion regarding the forming tool 508 or the relationship between the forming tool 508 and the mold cavities 503d to 503s can be applied to any forming tool described herein or the relationship between any forming tool and any other mold cavity / mold cavities.

[0069] Thereafter, the second sheet 506 can be introduced between the upper mold part 502 and the lower mold part 503 and positioned adjacent to the bottom surface of the upper mold part 502 such that the plane of the sheet 506 is generally aligned with the bottom surface of the upper mold part 502, as Figure 5H shown. Once the second sheet 506 is positioned relative to the bottom surface of the upper mold part 502, the second sheet 506 can then be brought into contact with the bottom surface. That is, the system 500 can be configured to move the upper mold part 502 such that the second sheet 506 can be brought into contact with the bottom surface of the upper mold part 502. As Figure 5IAs shown, in some cases, the forming tool 528 can then be introduced into the system 500 between the upper die part 502 and the lower die part 503 such that when pressed into the second sheet 506, the forming tool is in a set position relative to the die cavity of the upper die part 502. In cases where the forming tool 528 includes a plurality of protrusions, once the forming tool is introduced into the system 500, each protrusion can be located at a predetermined position relative to one die cavity of the upper die part 502. In other cases, the second sheet 506 can be exposed to a low-pressure environment (e.g., below atmospheric pressure) to draw the sheet 506 into the die cavity of the upper die part 502.

[0070] Go to Figure 5J , once the second sheet 506 is introduced and positioned, the upper die part 502 and the lower die part 503 can be configured in a closed configuration. As used herein, the term "closed configuration" means that the upper die part and the lower die part are configured such that the bottom surface of the upper die part and the top surface of the lower die part are pressed against each other. In some instances, when the system 500 is in the closed configuration, the system 500 can be adapted to cause the first sheet 504 to partially bond to the second sheet 506 around the perimeter of each different set of corresponding die cavities formed between the upper die part and the lower die part. The system 500 can also be adapted to inject a fluid (such as a gas) into a portion of each partially bonded perimeter and seal (e.g., by adhesive bonding and / or thermal bonding) each partially bonded perimeter to form a cushioning element. Once formed, the cushioning element can include the fluid and / or the first sheet 504 and the second sheet 506, consist essentially of the fluid and / or the first sheet 504 and the second sheet 506, or consist of the fluid and / or the first sheet 504 and the second sheet 506, and the fluid and / or the first sheet 504 and the second sheet 506 cooperate to define a geometry or three-dimensional shape (e.g., thickness, width, and length), as will be discussed below.

[0071] Go to Figure 5K , once the cushioning element is formed, the upper die part 502 and the lower die part 503 can be configured in an open configuration to allow the formed cushioning element to leave the system 500 for further processing, such as cooling, trimming, inflating, and / or sealing the cushioning element.

[0072] Using the system described above, a method of forming one or more cushioning elements can be performed. For example, as Figures 5C to 5GAs shown, the method can include placing a first sheet 504 adjacent to an outer surface 503c of a first mold part 503, and the first mold part 503 can include a first cavity 503d. Then, a portion of the first sheet 504 can be pressed into the first mold part 503 and into the first cavity 503d by using a forming tool 508, and at least a portion of the forming tool 508 can extend into the first cavity 503d. To pull a portion of the first sheet 508 into the first cavity 503d, a negative pressure such as from a vacuum system 514 can be applied to the first cavity 503d.

[0073] In some cases, as Figures 5H to 5I shown, the method can further include placing a second sheet 506 adjacent to an outer surface 502c of a second mold part 502, and the second mold part 502 can include a second mold cavity (not shown). A portion of the second sheet 506 can be pressed into the second mold part 502 and into the second mold cavity by using a second forming tool 528, and at least a portion of the second forming tool 528 can extend into the second mold cavity. In some examples, to pull a portion of the second sheet 506 into the second mold cavity, a negative pressure such as from a vacuum system 516 can be applied to the second mold cavity. As Figures 5H to 5J shown, the second sheet 506 can be joined to the first sheet 504 to form a cushioning element, which can then be inflated (e.g., filled with a fluid).

[0074] After forming the cushioning element, each of the plurality of cushioning elements can have a three-dimensional shape suitable for a sole structure of a footwear article. In some examples, each of the plurality of fluid-filled cushioning elements can have an irregular three-dimensional shape, such as a tube shape. The tube shape can be, but is not limited to, a cylindrical tube shape, a rectangular tube shape, a U-shaped tube, an L-shaped tube, and / or an H-shaped tube.

[0075] Figures 6A to 6B is an image of a cushioning element 600 manufactured using the method of the present disclosure, each cushioning element having a cylindrical tube shape. As shown, eight cushioning elements 602, 604, 606, 608, 610, 612, 614, 616 are joined to each other at discrete locations, namely web regions 603, 605, 607, 609, 611, 613, 615. In these examples, a cushioning element (such as 602) can include a top surface 602a, a bottom surface (not shown), a first side surface 602b, and a second side surface 602c, where the first side surface 602b and the second side surface 602c are disposed between the top surface 602a and the bottom surface and are opposite to each other. Although not shown, in some examples, the top surface, the bottom surface, the first side surface, and / or the second side surface can each further include two end regions and a central region located between the two end regions.

[0076] After forming the cushioning elements, each of the plurality of cushioning elements can include one or more materials suitable for a sole structure of a footwear article. These one or more materials can correspond to one or more materials of the first sheet and the second sheet. In some instances, one or more materials of the first sheet and the second sheet can be barrier films. In these instances, the first sheet and the second sheet can each be made of an elastomeric material including one or more thermoplastic polymers and / or one or more crosslinkable polymers. In one instance, the elastomeric material can include one or more thermoplastic elastomeric materials, such as one or more thermoplastic polyurethane (TPU) copolymers, one or more ethylene-vinyl alcohol (EVOH) copolymers, and the like.

[0077] As used herein, "polyurethane" refers to copolymers (including oligomers) containing urethane groups (-N(C=O)O-). In addition to urethane groups, these polyurethanes can contain additional groups, such as esters, ethers, ureas, urethanes, biurets, carbodiimides, oxazolidines, isocyanurates, uretdiones, carbonates, and the like. In one aspect, one or more of the polyurethanes can be produced by polymerizing one or more isocyanates with one or more polyols to produce copolymer chains having (-N(C=O)O-) bonds.

[0078] Examples of suitable isocyanates for producing polyurethane copolymer chains include diisocyanates, such as aromatic diisocyanates, aliphatic diisocyanates, and combinations thereof. Examples of suitable aromatic diisocyanates include toluene diisocyanate (TDI), adducts of TDI with trimethylolpropane (TMP), methylene diphenyl diisocyanate (MDI), xylene diisocyanate (XDI), tetramethylbenzene diisocyanate (TMXDI), hydrogenated xylene diisocyanate (HXDI), naphthalene 1,5-diisocyanate (NDI), 1,5-tetrahydronaphthalene diisocyanate, p-phenylene diisocyanate (PPDI), 3,3'-dimethyl diphenyl-4,4'-diisocyanate (DDDI), 4,4'-dibenzyl diisocyanate (DBDI), 4-chloro-1,3-phenylene diisocyanate, and combinations thereof. In some embodiments, the copolymer chains are substantially free of aromatic groups.

[0079] In certain instances, the polyurethane polymer chains are produced from diisocyanates including HMDI, TDI, MDI, H12 aliphatic compounds, and combinations thereof. In one aspect, thermoplastic TPU can include polyester-based TPU, polyether-based TPU, polycaprolactone-based TPU, polycarbonate-based TPU, polysiloxane-based TPU, or combinations thereof.

[0080] In another example, the polymer layer can be formed from one or more of the following: EVOH copolymers, poly(vinyl chloride), polyvinylidene polymers and copolymers (e.g., polyvinylidene chloride), polyamides (e.g., amorphous polyamides), amide-based copolymers, acrylonitrile polymers (e.g., acrylonitrile-methyl acrylate copolymers), polyethylene terephthalate, polyetherimide, polyacrylic imide, and other polymeric materials known to have a relatively low gas permeability. Blends of these materials, as well as blends with the TPU copolymers described herein and optionally combinations including polyimides and crystalline polymers are also suitable.

[0081] The first sheet and the second sheet can be multilayer films comprising two or more layers. The first sheet and the second sheet can each independently comprise alternating layers of one or more TPU copolymer materials and one or more EVOH copolymer materials, wherein the total number of layers in each of the first sheet and the second sheet comprises at least four (4) layers, at least ten (10) layers, at least twenty (20) layers, at least forty (40) layers, and / or at least sixty (60) layers.

[0082] The first and second sheets can comprise, consist essentially of, or consist of one or more barrier materials. As used herein, the term "barrier material" refers to a material that comprises, consists essentially of, or consists of one or more gas barrier compounds. The gas barrier compound can be a polymeric gas barrier compound (i.e., a gas barrier polymer), or can be a non-polymeric gas barrier compound, such as an inorganic gas barrier compound. The barrier material can be a polymeric barrier material that comprises, consists essentially of, or consists of one or more gas barrier polymers. The barrier material can be a polymeric barrier material that comprises, consists essentially of, or consists of a mixture of one or more non-gas barrier polymers and one or more gas barrier polymers, or the barrier material comprises, consists essentially of, or consists of a mixture of one or more non-gas barrier polymers and one or more non-polymeric gas barrier compounds. The barrier material can comprise, consist essentially of, or consist of a non-polymeric barrier material, i.e., a material that comprises, consists essentially of, or consists of non-polymeric gas barrier compounds. The barrier material can be present in a structure in a region that comprises a polymeric material and a non-polymeric barrier material, such as a polymeric film coated with one or more layers of non-polymeric barrier material. The gas transmission rate of the portion of the buffer element that comprises the barrier material can be less than 4 or less than 3 or less than 2 cubic centimeters per square meter per atmosphere per day. When measured at 23 degrees Celsius and 0% relative humidity, for a barrier film having a thickness of from about 72 microns to about 320 microns, the gas transmission rate of the barrier film can be less than 4 or less than 3 or less than 2 cubic centimeters per square meter per atmosphere per day. When measured at 23 degrees Celsius and 0% relative humidity, for a film having a thickness of from about 72 microns to about 320 microns, the gas transmission rate of the barrier film is from about 0.1 to about 3, or from about 0.5 to about 3, or from about 0.5 to about 3 cubic centimeters per square meter per atmosphere per day, including from about 0.1 to about 3, or from 0.5 to about 3, or from 0.5 to about 3 cubic centimeters per square meter per atmosphere per day. The gas transmission rate, such as the oxygen or nitrogen transmission rate, can be measured using ASTM D1434.

[0083] The barrier material may comprise one or more non-polymeric gas barrier compounds, consist essentially of one or more non-polymeric gas barrier compounds, or consist of one or more non-polymeric gas barrier compounds, and the non-polymeric gas barrier compounds include one or more inorganic gas barrier compounds. The one or more inorganic gas barrier compounds may be selected from the forms of carbon, silica, silicate, clay, metal, and any combination thereof. The metal may include metal oxides or metal alloys. The one or more inorganic gas barrier compounds may take the form of fibers, particles, platelets, or a combination thereof. The fibers, particles, or platelets may be nanostructured, including nanofibers, nanoparticles, nanoplates, and combinations thereof. Examples of inorganic barrier compounds include carbon fibers, glass fibers, glass flakes, silica particles, silica platelets, silica flakes, silicate particles, silicate platelets, silicate flakes, calcium carbonate particles, clay particles, clay platelets, mica platelets, talc particles, carbon black particles, graphite particles, graphite platelets, graphite flakes, metal particles, metal platelets, metal flakes, etc. The barrier material may include an inorganic gas barrier component composed of all the inorganic gas barrier compounds present in the barrier material. The inorganic gas barrier component may be composed of one or more clays. Suitable clays include bentonite, montmorillonite, kaolinite, and mixtures thereof. Optionally, in addition to the one or more non-polymeric gas barrier compounds, the barrier material may further include one or more additional components, such as polymers, processing aids, colorants, or any combination thereof. When one or more inorganic gas barrier compounds are included in the barrier material, the total concentration of the inorganic gas barrier component present in the barrier material may be less than 60 wt% of the barrier material, or less than 40 wt%, or less than 20 wt%.

[0084] One or more gas barrier compounds of the barrier material may comprise one or more gas barrier polymers, consist essentially of one or more gas barrier polymers, or consist of one or more gas barrier polymers. The barrier material may be a thermoplastic material, meaning that the polymeric components of the barrier material consist of one or more thermoplastic polymers, optionally including thermoplastic polymers that are not gas barrier polymers. The barrier material may comprise one or more thermoplastic gas barrier polymers, consist essentially of one or more thermoplastic gas barrier polymers, or consist of one or more thermoplastic gas barrier polymers. The barrier material includes a gas barrier polymer component consisting of all the gas barrier polymers present in the barrier material. The gas barrier polymer component of the barrier material may consist of gas barrier polymers of one or more single classes of polymers, such as one or more polyolefins. The gas barrier polymer component may consist of gas barrier polymers having similar or identical chemical structures, such as one or more ethylene-vinyl alcohol copolymers. Optionally, the barrier material may also include one or more non-polymeric additives, such as one or more fillers, processing aids, colorants, or any combination thereof; or one or more non-polymeric barrier compounds, such as one or more inorganic barrier compounds. Many gas barrier polymers are known in the art. Examples of gas barrier polymers include vinyl polymers such as vinylidene chloride polymers, acrylic polymers such as acrylonitrile polymers, polyamides, epoxy polymers, amine polymers, polyolefins such as polyethylene and polypropylene, their copolymers (such as ethylene-vinyl alcohol copolymers), and their mixtures. When the barrier material comprises one or more gas barrier polymers, consists essentially of one or more gas barrier polymers, or consists of one or more gas barrier polymers, the one or more gas barrier polymers may be selected from vinyl polymers, acrylic polymers, amide polymers, imide polymers, epoxy polymers, olefin polymers, any of their homopolymers, any of their copolymers, and any of their mixtures. One or more gas barrier polymers may comprise one or more thermoplastic gas barrier polymers, consist essentially of one or more thermoplastic gas barrier polymers, or consist of one or more thermoplastic gas barrier polymers. Examples of thermoplastic gas barrier polymers include thermoplastic vinyl homopolymers and copolymers, thermoplastic acrylic homopolymers and copolymers, thermoplastic amine homopolymers and copolymers, thermoplastic polyolefin homopolymers and copolymers, and their mixtures. One or more gas barrier polymers may comprise one or more thermoplastic polyethylene copolymers, consist essentially of one or more thermoplastic polyethylene copolymers, or consist of one or more thermoplastic polyethylene copolymers. One or more gas barrier polymers may comprise one or more thermoplastic ethylene-vinyl alcohol copolymers, consist essentially of one or more thermoplastic ethylene-vinyl alcohol copolymers, or consist of one or more thermoplastic ethylene-vinyl alcohol copolymers.The thermoplastic ethylene-vinyl alcohol copolymer can be an ethylene-vinyl alcohol copolymer having an ethylene content of from about 28 mol% to about 44 mol%, or from about 32 mol% to about 44 mol%. The one or more gas barrier polymers can include, consist essentially of, or consist of one or more polyethyleneimines, polyacrylic acids, polyethylene oxides, polyacrylamides, polyamidoamines, or any combination thereof.

[0085] The barrier material (including the first barrier material, the second barrier material, etc.) can have a low gas permeability. For example, when forming a single-layer film consisting essentially of the barrier material, for a film having a thickness of from about 72 microns to about 320 microns, the single-layer film can have a low gas permeability of less than 4 cm³ / m² / atm / day when measured at 23 degrees Celsius and 0% relative humidity, and can be measured using ASTM D1434.

[0086] The barrier material can include, consist essentially of, or consist of one or more gas barrier compounds. The one or more gas barrier compounds can include, consist essentially of, or consist of one or more gas barrier polymers, or can include one or more non-polymeric gas barrier compounds, including one or more inorganic gas barrier compounds. The barrier material can include, consist essentially of, or consist of a combination of at least one gas barrier polymer and at least one inorganic gas barrier compound. The combination of at least one gas barrier polymer and at least one inorganic gas barrier compound can include a blend or mixture, or can include a composite in which fibers, particles, or platelets of the inorganic gas barrier compound are surrounded by the gas barrier polymer.

[0087] Regardless of the shape of the buffer element, each of the plurality of buffer elements formed by the systems and methods herein can have improved wall thickness uniformity and can include less material than conventional buffer elements, as Figures 7A to 11 shown by the data and measurements presented. Without being bound by a particular theory, these features can be imparted by the spatial positioning of the forming tool as described herein.

[0088] The following clauses provide exemplary configurations of systems and methods for forming one or more buffer elements using the thermoforming process described above.

[0089] Clause 1. A method of forming a buffer element, the method comprising: placing a first sheet adjacent to an outer surface of a first die portion, the first die portion including a first die cavity; using a forming tool to press a portion of the first sheet into the first die portion and into the first die cavity, wherein at least a portion of the forming tool extends into the first die cavity; applying a negative pressure to the first die cavity to draw the portion of the first sheet into the first die cavity; and joining a second sheet to the first sheet to form the buffer element.

[0090] Clause 2. The method according to Clause 1, wherein pressing the portion of the first sheet into the first die portion includes extending the portion of the forming tool into the first cavity until an outermost surface of the forming tool is positioned about 0.1 mm to about 4 mm away from an inner surface of the first cavity.

[0091] Clause 3. The method according to Clause 1, wherein an innermost surface of the first cavity has a wavy curvature.

[0092] Clause 4. The method according to Clause 3, wherein when viewed from a favorable position adjacent to an opening of the first cavity, the innermost surface of the first cavity has: (1) a recessed first portion; (2) a protruding second portion that is laterally adjacent to the recessed first portion; and (3) a recessed third portion that is laterally adjacent to the protruding second portion on a side opposite to the recessed first portion of the protruding second portion.

[0093] Clause 5. The method according to Clause 4, wherein, when viewed from a favorable position at the innermost surface of the first cavity, the portion of the forming tool that extends into the first cavity has: (1) a protruding first portion that is vertically aligned with the recessed first portion of the first cavity; (2) a recessed second portion that is vertically aligned with the protruding second portion of the first cavity; and (3) a protruding third portion that is vertically aligned with the recessed third portion of the first cavity.

[0094] Clause 6. The method according to Clause 5, wherein a vertical space between the innermost surface of the first cavity and the outermost surface of the forming tool is the same throughout a length of the portion of the forming tool that extends into the first cavity.

[0095] Clause 7. The method according to clause 1, wherein before joining the second sheet to the first sheet, the method further comprises: placing the second sheet adjacent to an outer surface of a second die portion, the second die portion including a second die cavity; using a second forming tool to press a portion of the second sheet into the second die portion and into the second die cavity, wherein at least a portion of the second forming tool extends into the second die cavity; and applying a negative pressure to the second die cavity to pull the portion of the second sheet into the second die cavity.

[0096] Clause 8. The method according to clause 1, wherein before joining the second sheet to the first sheet, the method further comprises: placing the second sheet adjacent to an outer surface of a second die portion, the second die portion including a second die cavity; using a second forming tool to press a portion of the second sheet into the second die portion and into the second die cavity, wherein at least a portion of the second forming tool extends into the second die cavity.

[0097] Clause 9. The method according to clause 1, wherein the first die includes a plurality of first cavities spaced apart from each other along a longitudinal axis of the first die portion, wherein a length of each first die cavity extends transversely to the longitudinal axis.

[0098] Clause 10. The method according to clause 9, wherein the first die portion includes four first die cavities, wherein each of two inner longitudinal die cavities of the four first die cavities has a greater length and height than each of two outer longitudinal die cavities of the four first die cavities.

[0099] Clause 11. The method according to clause 1, wherein before joining the second sheet to the first sheet, the method further comprises exposing the first sheet or the second sheet to thermal energy in a range from about 125 °C to about 225 °C.

[0100] Clause 12. The method according to clause 1, further comprising inflating the buffer element.

[0101] Clause 13. The method according to clause 1, wherein the first sheet is thinner than the second sheet.

[0102] Clause 14. The method according to clause 1, wherein the first sheet or the second sheet includes a barrier film, the barrier film including an elastomeric material, the elastomeric material including one or more thermoplastic polymers or one or more crosslinkable polymers.

[0103] Clause 15. The method according to Clause 1, wherein the forming tool comprises a foam material having a compressive strength in the range from about 90 MPa to about 97 MPa or a service temperature in the range from about 149 °C to about 204 °C.

[0104] Clause 16. The method according to Clause 1, wherein the buffer element has a cylindrical tube shape and comprises a top surface, a bottom surface, a first side surface and a second side surface, the first side surface and the second side surface being disposed between the top surface and the bottom surface and opposite to each other.

[0105] Clause 17. The method according to Clause 15, wherein at least a part of the bottom surface has a thickness in the range from about 0.75 mm to about 0.95 mm, or wherein at least a part of the first side surface or the second side surface has a thickness in the range from about 0.45 mm to about 0.7 mm.

[0106] Clause 18. The method according to Clause 16, wherein the difference between the thickness of at least a part of the first side surface or the second side surface and the thickness of at least a part of the bottom surface is less than about 0.1 mm.

[0107] Clause 19. A system for thermoforming a buffer element, the system comprising: an upper die part having a plurality of die cavities; a lower die part having a plurality of die cavities; and a forming tool, wherein the system is configured to: introduce a first sheet between the upper die part and the lower die part; introduce the forming tool between the upper die part and the lower die part at a set position relative to the die cavity of the lower die part; press the forming tool into the first sheet; and introduce a second sheet between the upper die part and the lower die part.

[0108] Clause 20. The system according to Clause 19, wherein the system is further configured to: introduce a second forming tool between the upper die part and the lower die part at a set position relative to the die cavity of the upper die part; and press the second forming tool into the second sheet.

Claims

1. A method of forming a cushioning element, the method comprising: placing a first sheet adjacent to an outer surface of a first mold portion, the first mold portion comprising a first mold cavity; pressing a portion of the first sheet material into the first mold portion and into the first mold cavity using a forming tool, wherein at least a portion of the forming tool extends into the first mold cavity; applying negative pressure to the first mold cavity to draw the portion of the first sheet into the first mold cavity; A second sheet of material is joined to the first sheet of material to form the cushioning element.

2. The method of claim 1 , wherein pressing the portion of the first sheet into the first mold portion comprises extending the portion of the forming tool into the first cavity until an outermost surface of the forming tool is positioned about 0.1 mm to about 4 mm away from an inner surface of the first cavity. The method according to claim 1 , wherein an innermost surface of the first cavity has a wavy curvature.

4. The method of claim 3, wherein the innermost surface of the first cavity, when viewed from a vantage point adjacent to an opening of the first cavity, has: (1) a concave first portion; (2) a convex second portion laterally adjacent to the concave first portion; and (3) A concave third portion laterally adjacent to the convex second portion at a side of the convex second portion opposite to the concave first portion.

5. The method of claim 4, wherein, from a vantage point at the innermost surface of the first cavity, the portion of the molding tool extending into the first cavity has: (1) a convex first portion vertically aligned with the concave first portion of the first cavity; (2) a recessed second portion vertically aligned with the protruding second portion of the first cavity; and (3) a convex third portion vertically aligned with the concave third portion of the first cavity. 6 . The method of claim 5 , wherein the vertical space between the innermost surface of the first cavity and the outermost surface of the forming tool is the same throughout the length of the portion of the forming tool extending into the first cavity.

7. The method according to claim 1, wherein before joining the second sheet to the first sheet, the method further comprises: placing the second sheet adjacent to an outer surface of a second mold portion, the second mold portion comprising a second mold cavity; pressing a portion of the second sheet into the second mold portion and into the second mold cavity using a second forming tool, wherein at least a portion of the second forming tool extends into the second mold cavity; as well as Negative pressure is applied to the second mold cavity to draw the portion of the second sheet into the second mold cavity.

8. The method according to claim 1, wherein before joining the second sheet to the first sheet, the method further comprises: placing the second sheet adjacent to an outer surface of a second mold portion, the second mold portion comprising a second mold cavity; A portion of the second sheet is pressed into the second mold portion and into the second mold cavity using a second forming tool, wherein at least a portion of the second forming tool extends into the second mold cavity.

9. The method of claim 1, wherein the first mold comprises a plurality of first cavities spaced apart from one another along a longitudinal axis of the first mold portion, wherein a length of each first mold cavity extends transverse to the longitudinal axis.

10. The method of claim 9, wherein the first mold portion comprises four first mold cavities, wherein each of two inner longitudinal mold cavities of the four first mold cavities has a greater length and height than each of two outer longitudinal mold cavities of the four first mold cavities.

11. The method of claim 1, wherein prior to bonding the second sheet to the first sheet, the method further comprises exposing the first sheet or the second sheet to thermal energy in a range from about 125°C to about 225°C.

12. The method of claim 1, further comprising inflating the cushioning element.

13. The method of claim 1, wherein the first sheet is thinner than the second sheet.

14. The method of claim 1, wherein the first sheet or the second sheet comprises a barrier film comprising an elastomeric material comprising one or more thermoplastic polymers or one or more cross-linkable polymers.

15. The method of claim 1, wherein the forming tool comprises a foam material having a compressive strength in a range from about 90 MPa to about 97 MPa or a use temperature in a range from about 149°C to about 204°C.

16. The method according to claim 1, wherein the cushioning element has a cylindrical tube shape and includes a top surface, a bottom surface, a first side surface, and a second side surface, the first side surface and the second side surface being disposed between the top surface and the bottom surface and opposite to each other.

17. The method of claim 15, wherein at least a portion of the bottom surface has a thickness in a range from about 0.75 mm to about 0.95 mm, or wherein at least a portion of the first side surface or the second side surface has a thickness in a range from about 0.45 mm to about 0.7 mm. 18 . The method of claim 16 , wherein a thickness of the at least a portion of the first side surface or the second side surface and a thickness of the at least a portion of the bottom surface have a difference of less than about 0.1 mm.

19. A system for thermoforming a cushioning element, the system comprising: an upper mold portion having a plurality of mold cavities; a lower mold portion having a plurality of mold cavities; as well as Molding tool, wherein the system is configured to: introducing a first sheet between the upper mold portion and the lower mold portion; introducing the forming tool between the upper mold part and the lower mold part at a set position relative to the mold cavity of the lower mold part; pressing the forming tool into the first sheet; as well as A second sheet is introduced between the upper mould section and the lower mould section.

20. The system of claim 19, wherein the system is further configured to: introducing a second molding tool between the upper mold portion and the lower mold portion at a set position relative to the mold cavity of the upper mold portion; and The second forming tool is pressed into the second sheet.

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